|
PatentVote.com: Vote on your favourite invention!
|
|
 |
Title: Computer responsive postage meter
Description: Description:
FIELD OF THE INVENTION This invention relates generally to postage metering, and particularly concerns secured electronic calculating and postage printing equipment for achieving postage metering security in a computer-controlled high volume mailing operation. BACKGROUND AND SUMMARY OF THE INVENTION It is conventional for high volume mailers to avail themselves of the high speeds offered by modern electronic digital computers and chain printers, in order to reduce costs and increase their output. A typical prior art installation includes a computer which receives information as to the weight and destination of a package, and is programmed to calculate the required postage. A high speed computer output printer is slaved to the computer to print out the destination information on an address label which is subsequently affixed to the package. The computer also provides the calculated postage amount information to shipping department employees in some form which enables them to affix the proper amount of postage to the package. The most common way of accomplishing this is for the high speed printer to receive the postage amount information from the computer, and print it directly on the address label for the information of the employees who subsequently affix postage. This printing is not an actual government-authorized postage impression of the kind provided by a postage meter. The print impression made in a prior art installation as described above includes only the postage amount without any authorized postage validation symbols, and is provided for information only. Thereafter authorized postage of like amount must be affixed by an employee by affixing postage stamps or using a conventional manually controlled mechanical postage meter. The intervention of a human being, 3,255,439 of a mechanical postage metering device, slows down a high volume mailing operation of the kind described. Therefore it is desirable to have the authorized postage impression printed automatically in response to the computer-generated postage calculation. It is not enough, however, simply to connect the data output lines of the computer. to the input of some insecurely housed apparatus capable of printing authorized postage impressions, as suggested by U.S. Pat. No. 3,225,439 of L. G. Simjian. In accordance with applicable postal security regulations, there must be some secure means of accounting which assures postal officials that all the postage used is paid for. Normally a descending register is filled with a pre-paid postage credit balance, the register is decremented by the amount of postage dispensed, and the postage dispenser is locked when the postage balance falls too low. Subsequently the register can be recharged under secured conditions. It is also possible to extend postage credit to the user, keeping track of a debit balance which increases by the amount of the postage used, and billing the user subsequently. Those skilled in the computer arts will readily appreciate that it is possible to program the computer itself to take care of either type of bookkeeping described above. Such a solution is unsatisfactory, however, because digital computers are so easily re-programmed that an unscrupulous individual could thereby accomplish postal fraud. This invention contemplates, therefore, that the desired computer control of postage printing be achieved in conjunction with some form of secure, fixed-program postal accounting equipment. One approach which is within the contemplation of this invention is to use a mechanical postage meter which comprises a secure housing containing authorized postage printing means, a mechanical descending register for storing the postal credit balance, and mechanical guaranteeing for gauranteeing that all printed postage amounts are decremented from the register, all of which is conventional. The mechanical meter is modified in accordance with this invention, however, to provide it with an electrically actuated meter controller device connected to respond to electrical signals from the computer, and to translate those signals into a mechanical input for controlling all meter functions. (A system using a lever and clutch mechanism in an electrically actuated meter is shown in U.S. Pat. No. 3,692,988). The latter approach meets all security requirements, but is considered too slow to meet the speed requirements of some high volume mailing operations. When used in conjunction with an electronic digital computer and high speed printer, it may be necessary for the postage printer to produce approximately two or three postage impressions per second, and mechanical postage meters do not appear capable of withstanding such operating rates over a reasonable lifetime. In order to achieve longer operating lifetimes and/or higher operating speeds, a preferred form of the invention employs fast-acting electrically driven printing means, electrical means for storing the postage balance, and electrical calculating means for changing the postage balance in accordance with the amount of postage printed. The postage printing means is enclosed within a secure housing, and the electronic control circuitry, or at least that portion of it which bears the responsibility for postal security, is enclosed within the same housing or alternatively is in a separate secure housing and connected to the postage printer by means of secure electrical cable and connector devices. Equipment in accordance with this aspect of the invention can be used for printing various different kinds of numerical indicia under computer control. For example it is adapted for various non-postage applications having similar security problems, e.g. printing paychecks. It is also within the contemplation of this invention to provide appropriate security means which make it practical to use a high speed printer directly for postage printing, after appropriate modifications such as replacing standard print characters by special authorized postage symbols. That approach, however, has a number of disadvantages, one of which relates to the character size limitation of standard high speed printing equipment. It also involves undesirable interference with the electrical interface between the computer and the high speed printer, i.e. breaking into the electrical cable which connects the computer and the high speed printer in order to insert special circuitry for performing postal security functions. Therefore a preferred form of this invention provides a separate auxiliary printing mechanism which is arranged in one of several ways to print authorized postage impressions upon the address labels that are fed through the high speed printer. The high speed printer and the postage printer are both controlled ultimately by the computer, but they have individual electrical connections thereto, and therefore, only the connection to the postage printer need be designed with postal security problems in mind. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a computer-responsive authorized postage printing system in accordance with one embodiment of this invention, wherein an otherwise conventional high speed computer output printer is modified to print an authorized postage symbol, and is connected to so under control of an electronic postage metering circuit connected between the computer and the printer. FIG. 1A is an illustration of an authorized postage impression made by the apparatus of FIG. 1. FIG. 2 is a block diagram of an alternative embodiment of a computer-responsive authorized postage printing system in accordance with this invention, in which a self-contained mechanical postage meter is arranged to print upon the same paper web as a computer-driven high speed printer, and an automatic meter controller accepts computer instructions in electrical form and translates them into a mechanical input to the postage meter. FIG. 3 is a block diagram of another alternative embodiment of a computer-responsive authorized postage printing system in accordance with this invention, which uses a separate electrically actuated postage printer and electrical postal accounting equipment. Both the postage printer and at least that portion of the electronic circuitry which has responsibility for postal accounting are contained within a common secure housing. FIG. 4 is a block diagram of still another alternative embodiment of a postage printing system in accordance with this invention, in which electronic metering circuitry and an electrically actuated authorized postage printer are enclosed in separate secured housings and connected by a secured cable and secured electrical connector means. The postage printer is mounted piggy-back fashion upon a high speed computer output printer. FIG. 5 is a perspective view of an exemplary physical realization of a high speed printer and piggy-back postage printer mounted thereon, as illustrated in FIG. 4. FIG. 6 is an enlarged perspective view of the piggy-back postage printer and the supporting structure for mounting it on the high speed printer. FIG. 7 is another perspective view of the piggy-back postage printer. FIG. 8 is a perspective view of the printing mechanism of the piggy-back postage printer. FIG. 9 is a top plan view, with parts broken away and sectioned for clarity of illustration, of the piggy-back printer. FIG. 10 is an elevation view of the ribbon advance mechanism of the piggy-back printer. FIG. 11 is a front elevational view of the control panel of the electronic meter of FIGS. 3 of 4. FIG. 12 is a simplified block diagram of the circuitry of the electronic meter. FIGS. 13A through 13D comprise a more detailed block diagram of the same circuitry, when fitted together as shown in FIG. 13E. FIGS. 14 through 34 depict a more detailed view of the circuitry of FIG. 13, and associated timing and addressing diagrams for this circuitry. FIG. 14 shows a diagram including a plot of the clock, gray code counter polling the polling signals with respect to time. FIG. 15 depicts a diagram of the addressing signals plotted with respect to time. FIG. 16 illustrates a table of address allocation and arithmetic unit functions. FIG. 17 shows a circuit diagram for the gray code counter and the memory addressing counter. FIG. 18 depicts a circuit diagram for the polling circuit, the last address decoder and the combination lock switch. FIG. 19 illustrates a diagram of part of the control logic circuitry. FIG. 20 shows a diagram of the memory circuit. FIG. 21 depicts a diagram of the memory address decoder and memory input buffer circuitry. FIG. 22 illustrates a diagram for the arithmetic unit circuitry and memory output buffer circuitry. FIG. 23 shows a diagram for the insufficient postage decoder circuit, part of the interrupts and status indicator circuit and the arithmetic control circuit. FIG. 24 depicts a diagram for postage buffer circuitry. FIG. 25 illustrates a diagram of the print buffer circuitry. FIG. 26 shows a diagram for variable print module control circuitry and Binary Coded Decimal error detection circuitry. FIG. 27 depicts a diagram of the print wheel logic circuitry. FIG. 28 illustrates a diagram of the interfacing circuitry of the computer for this system. FIG. 29 shows a diagram of the meter status circuitry. FIG. 30 depicts a diagram for the memory power supply and voltage sensing circuits. FIG. 31 illustrates a diagram of the control power supply and initialization circuitry. FIG. 32 shows a diagram of the display switching control circuit. FIG. 33 depicts a diagram of the display logic control circuitry; and FIG. 34 illustrates a diagram of the direct memory read control logic circuitry. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 reference numeral 10 generally designates a high speed computer output printer, for example a chain printer such as the IBM Model 1403. The printer 10 is conventional in every respect, except that it is modified to include a type element for printing an authorized postage validation symbol. A web of mailing label paper 14 is pulled through the high speed printer during printing by means of the conventional paper tractor mechanism (not indicated), and the printer is capable of printing thereon both conventional alphanumeric symbols and the authorized postage symbol on command of a conventional programmable electronic digital computer 16. In modifying the high speed printer 10 to include the authorized postage validation symbol, one of the less frequently used conventional symbol print elements may be easily removed from the printing chain and replaced by a validation symbol print element. As printed by the modified chain printer 10, an authorized postage impression would appear as illustrated in FIG. 1A. This postage impression includes a dollar postage amount 11 and a pair of authorized postage symbols 12 before and after it. The postage amount 11 is printed by the conventional type elements used for general electronic data processing print-out purposes, and the validation symbols 12 are printed by the special substitute type element. The computer 16 is programmed to receive destination and package weight information, and from that information to calculate the amount of postage 11. Then the computer 16 transmits signals to the high speed printer 10 which cause it to print the address (not shown) and the calculated amount of postage 11 on the paper web 14, using conventional alphanumeric type elements. In addition, the printer 10, upon receiving an appropriate signal from the computer 16, prints the postage symbols 12 adjacent the postage amount 11 to validate the latter as an authorized postage impression. The paper web 14 is designed to be separated into individual mailing labels and then attached to individual packages for mailing purposes, as is presently conventional in high volume mailing operations. The high speed printer 10 is enclosed within a secured housing 18, along with an electronic postage metering circuit 20 which stores postal accounting information, recognizes the amount of postage calculated by the computer, and makes sure that the postage balance is altered by the amount of postage 11 every time that a computer instruction is sent to printer 10 for printing of the authorized postage validating symbol 12. The purpose of secured housing 18 is to make sure that no such command can reach the high speed printer 10 to cause it to print the authorized postage validating symbol 12 without an appropriate change in the postal accounting balance of circuit 20. To accomplish this, the secured housing 18 prevents access to the metering circuit 20 and the high speed printer 10. The term "secured housing" as used herein means a housing which either cannot be opened by unauthorized persons or cannot be opened by such persons without detection, or without engaging in counterfeiting. An example of a secured housing which is preferred for use with the present invention is the type which is currently employed in conventional mechanical postage meters. Such a housing cannot be opened without cutting a security closure which is protected by a lead seal having an authorized government impression thereon. Therefore in order to have access to the postage balance register of such a postage meter, a postage thief would either have to counterfeit the seal or leave behind telltale alterations of the security closures. The electronic meter 20 must be inserted into the electrical path between the computer 16 and high speed printer 10, because the computer must not be permitted to send any control signals to the high speed printer which are not monitored by the postage metering circuit 20. Otherwise, a dishonest computer programmer could easily redesign software so that computer 16 could access the authorized postage validating symbol 12 on the high speed printer 10 without causing the meter 20 to alter the postage balance by the proper amount. If every computer instruction reaching the high speed printer 10 passes through the meter 20, however, there will be an appropriate change in the postage balance for every postal amount printed. The need for splicing the electronic meter 20 into the cable 28 leading to the high speed printer 10 is, however, a disadvantage of the embodiment of FIG. 1. Both the manufactures and renters of computer installations frown upon the splicing of foreign circuits into the data cables between computers and peripheral equipment. Such splicing might also avoid various performance guarantees, since the manufacturers do not wish to be responsible for malfunctions that could conceivably have been caused by the foreign circuits. Another disadvantage of the approach illustrated in FIG. 1 is the fact that it causes difficulties for service personnel who maintain the printer 10 and meter 20. When repairs are required which necessitate opening the secure housing 18, special arrangements must be made with the postal authorities. The housing 18 may be designed to permit loading of paper 14, however, and other normal operating procedures, without the need for opening the housing or special supervision by postal authorities. For example, the paper 14 may be fed in through an opening in the housing 18 which is too small to permit tampering with the metering circuit 20 and electrical connection 22. Another disadvantage of the FIG. 1 embodiment relates to the fact that conventional high speed printer design places an upper limit on the size of type elements which can be used therein. Consequently the special postage validating symbol 12 may be too small for maximum visibility to postal employees handling the mail. An alternative embodiment of the invention which avoids these problems is seen in FIG. 2. There a computer 116 is connected by an uninterrupted cable 128 directly to a totally conventional, unmodified high speed printer 110. No foreign equipment is connected electrically to the printer, and there are no changes in its type elements. A conventional mechanical authorized postage metering and printing device 111 similar in internal design to mechanical postage meter devices that are in common use today, is installed near the high speed printer 110, and is arranged to print on the same continuous web of paper 114 as the high speed printer. The device 111 includes a mechanical postage printer 112 and mechanical postage registers 120 enclosed in a conventional secured housing 118. The mechanical postage meter and printing device 111 may be located either upstream or downstream from the high speed printer 110, relative to the direction of paper motion. The placement of the mechanical postage meter 111 in relation to the direction of paper motion determines whether the postage impression is printed before or after the address information printed by the high speed printer 110. In either case, the computer 116 is programmed to take account of the difference in location between the high speed printer and the postage printer, and actuates them in the appropriate time relationship, so that the matching address and postage amount are printed on the same mailing label, i.e. the same region of paper web 114. The meter and printer device 111 of this embodiment differs from conventional mechanical postage meters in that selecting the amount of postage and tripping the print mechanism is accomplished by a solenoid-actuated mechanism 130, instead of manually. (See U.S. Pat. No. 2,692,988). The solenoid-actuated mechanism in turn is driven by electrical signals coming over leads 132 and 134 from the computer 116 and additional electronic hardware 136 which may be required to interface the computer with the postage meter actuating solenoids. A disadvantage of the embodiment illustrated in FIG. 2 is that it is difficult to design a mechanical postage meter and printer device which can operate at speeds compatible with a high speed printer and electronic digital computer, unless the postage amount remains fixed between printing impressions. Two types of mechanical postage printers, both motor-driven, are commonly employed in this type of meter. One of these, the rotary type, cannot develop a great enough angular velocity without introducing dynamic problems; and the other type, the flat bed printer, has so much mass for the motor to accelerate all at once that is unsuitable for high speed operation. In addition, the rotating mechanical type of register mechanisms which are used for postage accounting in mechanical meters are not capable of high operating speeds. These factors slow down the print cycle of conventional postage meters to such an extent that insufficient time is left for changing the postage under wheels, if the mailing labels are to be printed at a rate compatible with electronic data processing equipment. In order to achieve such compatibility, preferred embodiments of the invention, illustrated in FIGS. 3 and 4 respectively, are designed to employ low inertia segmented flat bed postage printing mechanism driven directly by solenoids for high speed electrical actuation, and electronic digital techniques for high speed postage accounting. In the embodiment of FIG. 3 a solenoid-actuated authorized postage printer 212 and an electronic postage metering circuit 220 are both contained within a secured housing 218. The electronic meter 220 operates in response to the postage calculations performed by a computer 216, as represented by the arrow 232, and, as indicated by the arrow 234, drives solenoids 238 which cause the mechanism 212 to print a postage impression. The solenoid-actuated printer 212 acts on the same paper web 214 as a computer-responsive high speed printer 210, which is directly responsive to the computer 216 as indicated by the arrow 228. An advantage of the embodiment of FIG. 3 is that no secured electrical connectors or cables are required, since the security-sensitive electronic circuitry is enclosed within the same secured housing 218 as the postage printer 212. But a disadvantage of the embodiment of FIG. 3 is that putting the digital circuitry 220 within the same housing as the solenoids 238 exposes the digital circuitry to electrical noise. The approach illustrated in FIG. 4 avoids the electrical noise problem, and is most highly preferred. In this embodiment a solenoid-actuated postage printer 312 and its actuating solenoids 338 are enclosed in a first secured housing 318, while electronic metering circiutry 320 is enclosed in a separate secured housing 418 and connected to the solenoids 338 by a secured electrical cable 322 and secured connector 324. "Secured electrical connectors are cables" are defined as those which cannot be disconnected by unauthorized persons or cannot be disconnected by such persons without leaving traces or requiring counterfeiting. Connectors of this type are commercially available. See for example the XAC series of connectors made by Winchester Electronics of Oakville, Connecticut; these connectors have housings which are assembled by pairs of threaded fasteners having diametral holes. If a wire is passed through the diametral holes of both fasteners, and the ends of the wire are secured together by a lead seal having a government authorized impression, the threaded fasteners cannot be turned to disassemble the connector without violating the seal. Secured electrical cables are also commercially available; they are simply conventional conductor cables electrically shielded by a braided metal wire sheath, and the internal electrical conductors are connected to terminals inside the secured concector 324, which prevents anyone from disconnecting the cable 322 from the secured connector without dissassembling the secured connector. The other end of the cable 322 is similarly connected inside the secured housing 318. The metering circuitry 320 is effectively isolated by the metal housings 318 and 418 from electrical noise generated by the solenoids 338, yet a secured electrical relationship between the meter and the printer 312 is maintained. In this embodiment, a computer 316 provides calculated postage amount data to the electronic meter 320 as indicated by the arrow 332. The meter 320 has exclusive control over the print solenoids 338 by virtue of the second connection, and will not permit any amount of postage to be printed without simultaneously effecting a corresponding change in the electronically stored postage balance. Here again, the postage printer 312 and a high speed printer 310 act upon the same web of paper 314 in a known time relationship. The high speed printer 310 responds to instructions from the computer 316, as indicated by arrow 328. An advantageous feature shared by the embodiments of FIGS. 1, 3 and 4 is that through the use of electric digital techniques, useful feedback information is available from the postage printers 10, 212 and 312 to the electronic metering circuits 20, 220 and 320, and to the computers 16, 216 and 316, as indicated by the output arrows 40, 42 and 240, 242 and 340, 342 respectively. As a result, the computer can be advised of any error conditions existing in the postage printer before printing occurs. The computer then can take appropriate remedial steps as has been programmed. Such error conditions will be discussed more fully below, in connection with the specific electronic meter circuitry illustrated in FIGS. 12 and 13. Because the embodiment in FIG. 4 separates the printing components 312 and 338 from the electronics 320, it facilitates mounting the printer 312 and actuating solenoids 338 in piggyback fashion atop the high speed printer 310, as symbolized schematically in FIG. 4 by the placement of the housing 318 directly over the printer 310. Such piggy-back placement of the postage printer as an auxiliary mechanism mounted on the high speed printer has the advantage of closer correlation of the two printing mechanism in time and in space. The closer correlation in time eases the problem of printing the address and postage impression at different times. Thus in the embodiment of FIG. 4 the printing stations are separated by a relatively small number of print lines. The correlation in space makes for a more compact and convenient installation, since a postage printer mounted directly on the high speed printer does not occupy any additional floor space, and does not introduce the problem of a vulnerable paper web passing across the intervening space between the two printing devices. FIGS. 5 and 6 illustrate a high speed computer output printer 310 with the auxiliary postage printing mechanism 312 mounted in piggy-back fashion thereon. The computer output printer 310 may be any standard form of high speed printer of the kind which is normally driven by an electronic digital computer in conventional data processing installations. The particular high speed printer 310 illustrated in FIG. 5 is basically a standard IBM Model 1403 chain printer, which has been modified only to the extent necessary to mount the postage printer 312 thereon. The high speed printer 310 and the postage printer 312 receive their data inputs from the same digital computer (not shown), but they arrive over separate data input cables 328 and 322 respectively. The chain printer 310 impresses printed data upon paper web 314 in response to computer-generated signals received over data cable 328. The paper is advanced through the printer line-by-line by means of conventional paper tractors (not shown) acting upon sprocket holes 426 along either edge of the paper web. For mailing label applications, the paper web 314 comprises a backing sheet 428 which has the sprocket holes 426 punched therein and is wide enough to engage the paper tractors on either side of the postage printer 312, plus a centrally located front strip 430 which is narrower and consists of a series of individual mailing labels 430.1, 430.2, etc. Printing by the chain printer 310 takes place somewhat below the level of the postage printer 312, and after each segment of the mailing label strip 430 is completed the paper web 314 is pulled upwardly by the tractors. At a somewhat higher location within the printing station of the high speed printer 310, the postage printer 312 makes its printing impression upon the same mailing label strip 430, in response to a computer-generated data input which arrives over the data cable 322 and advises the postage printer of the computer-calculated amounts of postage required for each package. Because of their different print locations along the path of the paper web 314, there is a time difference between the related printing operations of printers 310 and 312, of which the computer must be programmed to take account. After both printing mechanisms 310 and 312 have finished printing their respective impressions thereon, the label strip 430 is separated from the backing sheet 428 and divided into individual mailing labels 430.1, 430.2, etc. which are then affixed to respective packages for mailing. The convention frame structure of an IBM Model 1403 chain printer 310 includes a pair of upper and lower frame members 422 and 423 respectively which extend horizontally across the printing station, and are used as the basic support for the piggy-back postage printer 312. A pair of side bars 432 are each bolted at their upper ends to the upper frame member 422 and at their lower ends to the lower frame member 423 of the main printer 310. At their lower ends, these side brackets 432 are formed with rearwardly projecting bar-supporting lugs 434 which receive the opposite ends of a threaded bar 436, and forwardly projecting hinge lugs 438 which interengage with hinge lugs 440 formed on a pair of end brackets 422. Hinge pins 444 and 446 pass downwardly through vertical holes which are drilled through all the hinge lugs 438 and 440 to secure the end brackets 422 to the side brackets 432 at either side of the printing station (see also FIGS. 7 and 9). The postage printer 312 is supported on a pair of slide rails 448 which extend horizontally between the two end brackets 422, and permit the postage printer 312 to slide horizontally to a position of printing relationship with the label strip 430. Set screws 450 hold the printer 312 in place after initial adjustment. As seen in FIGS. 6 and 9, a special platen assembly 452 for cooperating with the postage printer 312 is located directly behind the paper web 314, and is supported, with provision for lateral position adjustment, by threaded engagement with the bar 436 and clamping engagement with the lower frame member 423. The threaded engagement with the bar 436 is accomplished by a pair of upwardly and rearwardly extending tapped lugs 454. The clamping engagement with the lower frame member 423 is accomplished by front and rear plates 456 and 458 respectively which surround the lower frame member 423. Bolts 460 passing through the front plate 456 are threaded to the rear plate 458 to secure them in clamping relationship about the lower frame member 423. The actual platen surface is a hard rubber insert 462 which is received within an appropriate recess on the front surface of the front clamping plate 456. An inked ribbon 464 passes entirely around the outside of the postage printer housing 318 and downwardly between the postage printer mechanism 312 and the paper print-out sheet 314, in order to provide ink for postage impressions. As seen in FIGS. 6, 9 and 10, the ribbon 464 is advanced continuously by a roller 466 journaled between plates 468 and 469 and driven by a ribbon advance motor 470 secured to the plate 468. Both plates 468 and 469 are mounted on the exterior of the housing 318. Idler rollers 472 are rotatably mounted upon links 474 by a shaft 476, and the links in turn are pivotally mounted upon a shaft 478 journaled between the mounting plates 468 and 469. Torsion springs 480 are wrapped around shaft 478 and react against pins 481 and shaft 476 for biasing the idler rollers 472 against the ink ribbon 464 to maintain driving engagement with the motor-driven roller 466. With reference to FIGS. 7, 8 and 9, the postage printer 312 comprises a plurality of individual type segments 500 for printing the postage impression, including several which incorporate variable numerical information 501 to form the amount of postage. In the particular example illustrated, there are eight type segments 500, four of which (500.1 through 500.4) are of the variable numerical kind, allowing for a maximum postage amount of $99.99. The remainder of the type segments (500.5 through 500.8) are dedicated exclusively to non-variable information including an authorized government postage validation symbol 502 and an identification 506 of the city and country in which the mailer is located. The type segments 500 print through a window 508 formed on the undeside of the secure housing 318. The window 508 is just large enough to permit the type segments 500 to protrude therethrough for printing purposes, and does not admit the introduction of any tools which might be used to tamper with the mechanism inside the housing 318. The electrical signals for setting the variable numerical information on type segments 500.1 through 500.4, and for firing the print solenoids 338, arrive over the armored cable 322 entering one side of the secured housing 318. For a more complete understanding of the modifications necessary to mount the postage printer 312 upon a conventional high speed, computer-driven chain printer, see copending U.S. Pat. application Ser. No. 195,729, entitled "Computer-Responsive Supplemental Printer," filed the same day as this application by Lupkas, Freeman and Check, and assigned to the assignee of this application. FIGS. 8 and 9 illustrate the type of solenoid-actuated segmented printing mechanism which is preferred for rapid, computer-controlled printing of postage impressions in accordance with this invention. The paper web 314 comprising separable labels 314.1, 314,2 and the inked ribbon 464 are fed between the platen 462 and the printing segments 500. Each segment is first driven through a printing stroke by its respective solenoid 338, and subsequently is retracted by its respective return spring 522. For a more detailed description of the solenoidactuated printing mechanism, refer to the Lupkas, Freeman and Check application cited above. This type of printing mechanism is much faster than those used in mechanical postage meters, and has a much longer life when operated at speeds which are compatible with a computerdriven chain printer. It is not as fast as the chain printer 310, but compatability in this application does not require equality of speeds. In printing address labels for high volume mailing, a typical application requires the chain printer 310 to print several lines of address information on each label. If the output of the chain printer in such an application is considered in labels (rather than lines) per second, since the postage printing mechanism 312 need only make one printing impression per label, it is compatible in terms of speed if it can run at about two or three postage impressions per second. In contrast to conventional motor-driven postage printers, the solenoid-driven mechanism 312 is capable of achieving such speeds even if the postage amount is changed for every print impression. FIG. 8 illustrates the difference between the non-variable type segments 500.5 through 500.8 and the variable segments 500.1 through 500.4. Non-variable type segments 500.5 - 500.8 are solid slugs which contain only the type faces 523 for the fixed information in the postage impression. The other printing segments 500.1 - 500.4 are formed with hollow interiors 524 which open through windows 525. Surrounding the windows 525 are type faces for a continuation of the fixed information, but in addition type wheels 526 protrude through the windows 525 for printing purposes. These wheels contain respective sets of numerical type faces and are rotatable to select the number printed. The wheels 526 are part of respective number selection modules 528 received within the hollow interiors 524 of slugs 500.1 - 500.8. These modules include solenoid means (not shown) for number wheel rotation and electrical leads 530 for the input of number selection commands and the output of signals for verifying the angular positions of the number wheels. The variable information modules 528 are of a type available commercially from the Practical Automation Company of Shelton, Connecticut. The output leads 530 provide a data feedback circuit which can be used to send information back to the computer verifying that the number wheels 526 have been rotated to the desired position, so that the computer can determine whether its postage selection instructions have been carried out before it prints the postage. This is one type of information which is carried back to the electronic metering circuitry 220 or 320 and to the computer 216 or 316 by the feedback lines 240, 242 or 340, 342 of FIGS. 3 or 4. FIG. 11 shows the control and display panel 598 of the electronic meter 220 or 320. The meter includes a special type of self-scrambling combination lock switch which is used for recharging the postage credit balance under secure conditions. (See U.S. Pat. Nos. 3,664,231 and 3,034,329) The switch is manually operated by a knob 599 when the correct lock combination is entered on a keyboard 602. There is also an on-off switch 600, three indicator lights 604, 606 and 608 for power on, meter ready and insufficient postage respectively, a numerical display 610 which preferably has a ten digit capacity, and a set of display selector buttons 612, 614 and 616 which determine respectively whether the numerical display 610 shall show the amount in the ascending postage register, the descending postage register or the number of mailings recorded by a piece counter. Two additional buttons 618 and 620 are intended respectively to light up all the display elements for test purposes, or to turn the display off entirely. With reference to FIG. 12, in general terms the metering circuitry 220 or 320 of FIGS. 3 or 4 comprises postage printing circuitry 700 for driving print solenoids 238 or 338, and for providing the computer 216 or 316 with feedback information as to the condition of the variable number wheels 526 (FIG. 8). It also comprises accounting circuitry 702 which keeps track of the postal balance and alters that balance in response to the printing of postage. The electronic meter also comprises sequence control circuitry 706 which provides a hard-wired (i.e. fixed) program for stepping the electronic postage meter through a required series of operations. The sequence control circuitry 706 and the postal accounting circuitry 702 (non-volatile memory and arithmetric unit) both operate in response to timing circuitry 708 in order to achieve synchronous operation. Display circuitry 710 indicates the contents of the various postal accounting balances at a given time. A print confirmation circuit 711 advises the computer as to whether postage printing has been accomplished. All of the circuits in FIG. 8 are energized by power supply circuitry 712; and circuits 700, 702, 706 and 711 communicate with the computer through an appropriate interface 714. As used hereinafter in this description, the following definitions shall apply: Machine cycle -- eight gray code counter states or one address duration. Meter cycle -- duration of generation of entire sequence of 32 addresses. Mode -- any of three control states which generates a meter cycle. They are (1) ENTER POSTAGE, (2) ADD FUNDS and (3) CYCLE. ENTER POSTAGE -- mode in which postage amount to be printed is added to the ascending register and subtracted from the descending register. The piece counter is incremented by one. ADD FUNDS -- mode in which a fixed postage amount is added to the descending register - other registers remain unchanged. CYCLE -- mode in which all registers remain unchanged -- this mode is used principally in accessing memory contents for readout. It is also entered through the initialization procedure. Insufficient Postage -- an indicator which signals that the contents of the descending register are below the maximum amount the meter is capable of printing in one postage field. Polling -- process by which priority of the control states (modes) is implemented. A sequential check of modes is made until one is selected. In normal operation the following sequence takes place: One meter cycle in CYCLE mode takes place due to initialization. At least one free machine cycle follows before the next mode may be initiated. The mode may be any one of the three unless inhibited due to postage depletion or similar condition. Every meter cycle has at least one free machine cycle following it to allow polling. Use of this free machine cycle is also utilized in asynchronously reading meter memory contents, one 4 bit word at a time. The minimum access rate is one word per meter cycle although in practice register contents would be read out in sequence without intervening meter cycles. To fetch master memory contents, the computer feeds into the meter the address of the word it wants to read and a read command. At the end of the then current meter cycle, the meter will read the memory location and put the contents in the interface. To read the complete register, the computer has to generate the address sequence of the register, reading the contents one BCD digit at a time. As seen in greater detail in FIG. 13, the computer interface circuitry 714 comprises conventional hardware 798 (16 bit output port with strobe) which is designed to translate the timing and/or data code format of the computer into any other timing and/or data code format that may be employed by the electronic postage meter 220 or 320 (i.e., match the transmission lines to and from the computer). It also includes a computer status register 800 which accepts commands and postage amount data from the computer for use by the meter, and a meter status register 802 which accepts status indications and stored data from the meter circuitry and generates interrupts for use by the computer. The printing circuitry 700 includes the print solenoids 238 or 338 which drive the fixed and variable type segments 500.1-500.8; and solenoid 801 for operating a mechanism which locks the segments except during postage printing; switches 803 which sense the condition of the locking mechanism and the print segments 500.1 -500.8 to provide information needed by the print confirmation circuit 711; a circuit 805 which fires the solenoids 801 and 238 or 338 in a predetermined sequence; the variable number wheel modules 528, one for each variable digit of the postage amount, which rotate the number printing wheels 526 to select the postage digits in response to computer-generated electrical commands; and a buffer 804 which stores the calculated postage amount both for use by the variable modules 528 in setting the number wheels 526 and also for use by the postal accounting circuitry 702 in altering the postage balances. The postal accounting circuitry 702 comprises a memory 806 which includes an ascending postage register 808, a descending postage register 810, and a piece counter 812 which keeps track of the number of postage impressions made. In a preferred embodiment of the invention, the memory 806 is of the complementary metal oxide semiconductor (C/MOS) integrated circuit type, and requires a back-up battery 813 to preserve storage during A.C. power failures. The current drain of such memories is extremely small and storage would remain intact even if a power failure lasted for very long intervals. Memory addressing is done by a decoder circuit 814 whenever information is loaded into or fetched from the ascending or descending registers or the piece counter section of the memory 806. An arithmetic unit 816 is used to perform postal accounting calculations, i.e., substracting the amount of postage from the descending register 810 and adding it to the ascending register 808 when printing occurs, and adding postage to the descending register 810 when the meter is recharged. The arithmetic unit 816 includes buffers 818 into which the ascending and descending register contents (from memory 806) and the postage amount (from print buffer 804) are loaded prior to arithmetic operations. There is also an insufficient postage decoder circuit 820 which tests the content of the descending register 810 and determines when the postal credit balance falls below a predetermined threshold. This could be done, for example, by comparing the proposed amount of postage in the print buffer 804 with the remaining postage balance in the descending register 810. In a preferred embodiment of the invention, however, the circuit is simplified by using the same insufficient postage criterion that has long been employed in mechanical postage meters: i.e. whenever the descending postage credit balance equals or falls below the maximum amount of postage that the meter is capable of printing, in this instance $99.99, the balance is insufficient. For recharging the meter, there is the combination lock switch 860 which is operated by the knob 599 and keyboard 602 seen in FIG. 11. When the meter user pays a required sum, postal authorities give out the combination of the lock, permitting the meter user to operate the switch 860 once, which recharges the descending postage register 810 by a fixed increment equal to the sum paid. Thereafter the lock automatically rescrambles the combination so that another payment must be made to obtain the next combination from the postal authorities. The sequence control circuitry 706 includes a clock 822 which comprises a time base oscillator 824 (Digital Equipment Corp., Model No. 401) producing a pulse stream for driving a Gray code counter 826. The Gray code approach is employed to take advantage of its single bit transition characteristic, which provides a clean output for driving following circuitry. The output of the Gray counter 826 is used to drive a memory addressing counter 828, the count cycle of which is numerically equal to the total number of addresses in the memory 806. In a particular embodiment of the invention, for example, the capacity of the memory 806 is 32 addresses, each of which stores a single binarycoded decimal digit. Sixteen of those addresses are required for the ascending register 808, eight for the descending register 810, and eight for the piece counter 812. The memory addressing counter 828 steps through a sequence of all 32 memory addresses when driven by the Gray code counter 826. In order to make sure that each memory address count sequence of the circuit 828 is synchronized with the start of a Gray code count sequence of the circuit 826, an AND gate 830 ordinarily blocks the Gray count from reaching the memory addressing counter. However, when the Gray count reaches 0, a decoder circuit 832 sets a count starting flip-flop 834 which then enables the AND gate 830, permitting the Gray counter 826 to drive the memory addressing counter 828 via lead 831. At the end of a complete memory addressing sequence of circuit 828, the last memory address is decoded by a circuit 836 which then energizes a lead 837 to reset the count starting flip-flop 834. The sequence control circuitry 706 also includes a polling circuit 838 which is driven by the Gray code counter 826 and continually tests for three commands in the following priority sequence: (1) postage printing, (2) addition of funds to recharge the descending postage balance, and (3) display read-out. When one of these three operating modes is selected by the polling circuit 838, it sends the relevant mode command over a lead 840 to control logic circuitry 842 which then carries out the indicated activities in a hard-wired program sequence. The sequence control circuitry 706 also includes an initialization circuit 844 which includes circuitry 846 and 848 wired for fixed-program start-up and shut-down routines respectively. The display circuitry 710 includes the display selector panel switches 612-620 of FIG. 11, by means of which the user can request ascending or descending register or piece-counter information to be fetched from the memory 806 and displayed on the read-out 610, and can also test or blank the read-out 610. The latter circuit includes a buffer 852 to hold the display data fetched from the memory 806, and a decoder 854 for translating the data into a form suitable for use by the read-out 610. The power supply circuitry 712 includes main power supplies 856. These provide operating voltages required by all the circuits in FIG. 12; and are controlled by the on/off switch 600. There is also a voltage sensing circuit 858 which determines when there is a power failure or low voltage condition which might produce an error in the computations carried out by the arithmetic unit 816. When an out-of-tolerance voltage condition occurs, appropriate signals are sent to the initialization circuit 844 and meter status register 802. Panel indicator light 604 responds to the main power supplies 856 by indicating whether power is on. Panel light 606 responds to the voltage sensor circuit 858 by indicating whether the meter is ready for operation. Finally, panel light 608 responds to decoder 820 by indicating that an insufficient postage condition has occurred. The operation of the circuit of FIG. 13 will now be described. When the computer 216 or 316 calculates a postage amount to be printed on a mailing label, it transmits that information to the interface hardware 798. The interface hardware then translates the postage data into the data code format employed by the electronic postage meter circuit 220 or 320, and sends it to a data storage portion 862 of the computer status register 800. From there the postage amount is transmitted to the postage buffer 804 over a cable 864. The computer also stores a postage setting request in a command section 866 of the computer status register 800. That register in turn sends a printer signal to the control logic 842 over a lead 866. The control logic then issues an enter postage command over a lead 868 which causes the variable print modules 528 to be set to number positions representing the postage amount then contained in the print buffer 804. A data feedback line 870 carries back a signal from the variable modules 528 to convey print module status information to an interrupt and status indications section 872 of the meter status register 802, so that the computer will know when the print wheels 526 are properly set. If they are not properly set, that fact is reported back to the computer by the meter status register 802 and interface hardware 798. As a result, the computer does not issue a print command until the problem is resolved. But if the computer receives an indication that the variable print modules 528 are set to the proper numerical values, then it issues a print command which is transmitted through the interface hardware 798 and the command section 807 of the computer status register 800, and then over lead 874 to the first priority section of the polling circuit 838. The polling circuit enters the first priority printing mode, and sends a print mode command over the lead 840 to the control logic 842, which then issues print instructions over a lead 876. If a NAND gate 878 is not disabled, the print command passes through the gate and traverses leads 879 and 881 to the solenoid sequencing circuit 805. The latter then fires the solenoid 801 to unlock the print segments 500, and also fires the print solenoids 238 or 338 in sequential relationship (for a disclosure of the sequencing circuit 805, refer to the Lupkas, et al application cited above). The signal on lead 879 is also conveyed over lead 880 to the arithmetic unit 816 and causes it to perform a subtraction operation deducting the amount of postage from the descending register balance. In order to perform this operation, the arithmetic unit buffers 818 receive the postage amount information over a cable 882 from the print buffer, and they also receive the contents of the descending register 810 over a memory fetch cable 884. The necessary memory addressing operation to access the descending register is carried out by the memory address decoder 814 in response to address information received over a cable 886 via a data gate 905 and counter 828. The control logic circuit enables the gate 905 and arithmetic unit 816 by means of leads 904 and 894, respectively. The arithmetic unit 816 carries out its calculation and reloads the decremented postage balance back into the descending register section 810 of the memory 806 over a cable 895. Once again, the memory address decoder 814 performs the addressing function during loading, responding to the address information on the cable 886, while control signals arrive over leads 904 and 894 from control logic 842. In similar fashion, the amount of postage is added to the ascending register 808. The piece counter 812 is incremented each time the "enter postage" mode is initiated. Summarizing the printing operation, the computer command for setting the variable number wheels goes directly over lead 866 to the control logic 842, so that the setting function is carried out off-line with respect to the polling circuit 838. Then there is a feedback output over lead 870 to the computer to verify correct number wheel setting. Subsequently a print command goes over lead 874 to the polling circuit 838. When there is no higher priority operating mode requested, the print mode is entered and the control logic 842 issues a command which simultaneously fires the print solenoids 238 or 338, initiates the postage subtraction operation of arithmetic unit 816, increments the piece counter 812 and adds the postage amount to the ascending register. These operations cannot be carried out, however, unless the insufficient postage decoder 820 detects an adequate postage balance remaining in the descending register 810, and therefore enables the NAND gate 878. If the postal credit balance is insufficient, the output from the decoder 820 inhibits the NAND gate 878. As a result, the print solenoids are not fired, the postage balance is not decremented, the ascending register is not incremented and the piece counter is not incremented. In addition, the decoder output goes over a lead 896 to turn on the insufficient postage panel indicator light, and goes over a lead 898 to convey an insufficient postage indication back to the interrupt and status indication section 872 of the meter status register 802. The computer programmer can then use this indication to initiate any desired program routine. In a preferred embodiment of the postage printer, the print segments 500.1-500.8 are normally locked, for additional postage security, by the locking mechanism controlled by solenoid 801. The latter is unlocked only at the time that postage printing is initiated, and then locked again after printing. The switches 803 serve to sense the locked and unlocked condition of the lock mechanism, and also sense when print segments 500.1-500.8 respectively advance to print impact position upon energization of the print solenoids 238 or 338. For a complete disclosure of the locking mechanism, the solenoid 801 and the switches 803, refer to the Lupkas, et al application cited hereinbefore. When the print mechanism is unlocked by solenoid 801, switches 803 issue a signal on a lead 940 to set a lock mechanism flip-flop 942. The set output of that flip-flop then resets each one of a group of print segment flip-flops 944.1-944.8, associated with the print segments 500.1-500.8 respectively. Then the print segment flip-flops 944 wait to detect the movement of the print segments 500 to their print impact positions. As each print segment 500 advances to print impact position, a respective lead 946.1-946.8 is energized by the associated print confirmation switch 803 to set the associated print segment flipflop 944. All the set outputs of these flip-flops 944 lead to an eight-input NAND gate 948. The output of the NAND gate passes through a delay circuit 950 and is controlled by a coincidence gate 952. After printing the solenoid 801 is de-energized, and thus the loocking mechanism is relocked, causing one of the sensing switches 803 to issue another signal on a lead 952 which resets the flip-flop 942. The reset output of that flip-flop then enables coincidence gate 952. Upon the enabling of gate 952, the print confirmation circuit 711 can determine whether all the print segments 500.1-500.2 were successfully driven to print impact position during the preceding print operation. If all the print segments 500 have been driven to print impact position, the print confirmation switches 803 will have set all the flip-flops 944, and there will be no output from the NAND gate 948. Accordingly there will be no output from the print confirmation circuit 711 on its print segment status output lead 954. On the other hand, if any one or more of the print segments 500 fail to advance to print impact position, the corresponding flip-flops 944 will not be set. Consequently there will be an output from the NAND gate 948. This output, delayed by circuit 950, will pass through coincidence gate 952 when the latter is enabled at the end of the print operation, resulting in an output on lead 954 by which the print confirmation circuit 711 advises the interrupt and status indication section 872 of the meter status register 802 that postage printing has not been successfully carried out as ordered by the computer. The computer can then carry out any appropriate alarm subroutine dictated by the programmer. The next higher priority operating mode of the polling circuit 838 is the addition of funds to recharge the descending register 810 when an insufficient postage condition occurs. In order to avoid the need for carrying the postage printing mechanism and the accounting circuitry to a Post Office for recharging this invention contemplates the use of the selfscrambling combination lock switch 860. Such locks were previously developed for remote recharging of conventional postage meters. A mechanical combination lock of this type, which employs mutilated gears for scrambling, is disclosed in U.S. Pat. No. 3,034,329 of R. C. Pitney, and is suitable for use in the switch 860 of this circuit. As a preferable alternative, however, one might employ a keyboard-operated self-scrambling combination lock device as described in U.S. Pat. No. 3,664,231 issued May 23, 1972 by Walter J. Hanson, and assigned to the same assignee as the present application. Briefly, the Hanson device matches a hole pattern punches in a movable tape with a keyboardentered combination. If the combination is correct, the lock is released once, permitting the switch 860 to operate one time. Thereafter the tape is advanced to a new position, and consequently the switch cannot be operated without obtaining the next lock combination from postal officials. The result of each lock opening operation is to close the combination switch 860, sending a signal over a lead 900 to the second priority section of the polling circuit 838. This causes an add funds mode signal to be transmitted to the control logic 842 over the lead 840. An add funds signal is then transmitted from the control logic 842 over a lead 902 to the arithmetic unit 816. The effect of that signal is to cause a predetermined increment of postage, equal in amount to the payment made to the postal authorities in order to obtain the lock combination, to be added to the descending register balance. The descending register portion 810 of the memory 806 is accessed and then reloaded with the new postage balance by the memory address decoder 814 in response to an addressing control signal arriving over a lead 904 from the control logic 842. The addressing control signal enables gate 905 during the memory addressing count sequence of circuit 828. The third priority operating mode of the polling circuit 838 is the reading out of information into the panel display 610. This operating mode is entered in response to one of the manually operated panel switches 612-618, which determine whether the display is to show the contents of the ascending register, descending register or piece counter sections of the memory 806, or to light up a test display which energizes all read-out elements. Any of these switches generates a signal (represented by arrow 619) which causes the polling circuit 838 to enter mode No. 1. The switch 620 cancels the read-out operating mode entirely. In response to a read-out mode signal on the lead 840 coming from the polling circuit 838, the control logic 842 sends a signal over address control lead 904 which enables gate 905 during the memory addressing count sequence. Memory contents are sequentially read out on cable 884. The signal on lead 906 from the control logic 842 strobes the selected information into the read-out 610. The preferred form of display for this circuit is a lightemitting diode array with built-in integrated circuit decoding logic 854. The computer can also access the memory contents at will, and fetch data therefrom to use for any purpose that the programmer desires. In order to accomplish this, the computer inserts the desired memory address into the data section 862, and also sends a memory reading instruction to command section 807 of the computer status register 800, which in turn sends a read memory signal over a lead 912 directly to the control logic 842, bypassing the polling circuit 838. The control logic 842 in turn sends a signal over the lead 892 to enable the data gate 888, admitting the computer-generated memory address arriving over cable 889 to the memory address decoder 814. This results in fetching the requested ascending register, descending register, or piece counter data from the memory 806 over cable 884, and inserting it into a data portion 914 of the meter status register 802. Then a computer can obtain the desired information from the meter status register. There is a possibility of arithmetic error if postage computations are performed when the logic voltage levels supplied by the main power supply circuits 856 are not within tolerance. In order to make sure that all arithmetic computations take place under proper voltage conditions, and thus avoid postal accounting errors, the start-up program section 746 of the initialization circuit 844 does not turn on until it gets a signal over a lead 915 from the voltage sensor circuit 858 indicating that all logic levels are within tolerance. The initialization circuit 844 produces a start signal on a lead 916 which turns on the memory address decoder 814 and also makes sure that the gate controlling flip-flop 834 is initially reset. In the event of a power failure, low voltage condition or shut-down of the meter, the voltage sensor 858 indicates a power-off situation to the shut-down program section 848 of the initialization circuit 844. At that time, the initialization circuit sends a stop signal on a lead 918 to a NAND gate 920. The NAND gate inhibits the stop signal if the polling circuit 838 signals over a lead 922 that an arithmetic calculation is currently in progress; i.e. the meter is in mode No. 1 or 2. Under those circumstances, calculation is allowed to proceed to completion. The power supplies 856 are designed with enough capacitance to allow operation at proper voltage levels for sufficient time to complete any arithmetic operation that may be in progress, even after total power failure. But after the present calculation is concluded, the polling circuit 838 and lead 922 cause NAND gate 920 to pass the stop signal out over line 921 in order to turn off the memory address decoder 814 and thereby preserve the memory contents unchanged for the duration of the power failure or other abnormal condition. An additional lead 924 coming from the voltage sensor 858 lights up the meter-ready panel indicator light 606 when the logic voltages come up to required levels, and another lead 926 conveys the same meter-ready indication to the interrupt and status indication section 87 Other info: Inventors: Check, Jr., Frank T. (Orange, CT, US) Eckert, Jr., Alton B. (Norwalk, CT, US) Hinman, Bruce E. (Ridgefield, CT, US) Jones, Jr., Howell A. (Fairfield, CT, US) Lupkas, Raymond R. (Trumbull, CT, US) McFiggans, Robert B. (Stamford, CT, US) Application Number: 406898 Filing Date: 1973-10-16 Publication_date: 1976-02-10 Assignee: Pitney-Bowes, Inc. (Stamford, CT) Primary Class(es): 705/402 346/33R, 361/56, 380/52, 705/410 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Springborn, Harvey E. Assistant Examiner: Woods, Paul R. Attorney: Soltow, Jr.; William D., Scribner; Albert W., Salzman; Robert S. |
|