A digital mark printer

Abstract: An improved digital mark-printer operated under control of a microprocessor and control program. A main shaft including a printing head with a plurality of numeral wheels is driven by drive circuits and the position of the shaft and wheels are sensed by sensor circuits, all under control of the microprocessor.

Description: The present invention relates to a digital mark-printer according to claim 1 or 2. Similar printing functions are disclosed in UK Patent Application No. 2166389 in which a postage printing mechanism is provided with settable postage printing elements such as print wheels, driven by a drive mechanism such as stepping motors at different operating speeds to set the postage printing elements to selected postage value to be printed, a control system such as a microcomputer controls the drive mechanism and its speed of operation, a position detecting system such as an amplifier comparator, opto-interruptor, slotted disc is coupled between postage value selection and the postage printing mechanism and is further coupled to the control system, for detecting the actual setting of the postage printing mechanism settable postage printing element setting and allowing control means to verify the setting and the control system us operable in response to print element setting error information to control the speed at which the drive mechanism operates to drive the postage printing mechanism settable postage printing elements to a selected postage value. In operation the speed of setting is increased after each setting operation and when improper setting is detected the setting speed is reduced. The postage meter is then operated for the duration of its use at the highest possible setting speed where no error is encountered. However in this prior proposal, there are difficulties arising from movably mounted motors which must rotate together with the main shaft which we have sought to overcome to provide a compact arrangement of rotating parts. A primary object of the present invention is to provide a fully automatic mark-changeable printer which through control of stored program in a micro-processor system can print a date mark, cost mark, etc., with more print marks available than in the prior art. A further object of the present invention is to provide an electro-mechanically integrated, fully automatic digital mark-printer system which is computerised so that it can cooperate with other peripheral equipment to provide an unmanned duly automatic system for use in business. The above and other objects and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. Fig. 1 is a block diagram of a digital mark-printer in accordance with the present invention; Fig. 2 is a perspective view of the overall digital mark-printer of an embodiment in accordance with the present invention; Fig. 3 is a perspective view of a roller printing head of an embodiment in accordance with the present invention; Fig. 4 is a perspective view of the settable mechanism of the roller printing head according to Fig. 2 wherein for clarity, only one numerical wheel set with its respective driver is shown; Figs. 5 to 7 are cross-sectional views of different arrangements of a wheel driver for eight, ten, twelve numeral wheels according to Fig. 2; Figs. 8A and 8B are side elevational views of a preferred embodiment of the present invention, Fig. 8A showing a ready state, Fig. 8B showing a printing state; Fig. 9 is a perspective view of the digital mark-printer of another embodiment of the present invention; Fig. 10 shows a plan view of main shaft and numeral wheel driving system according to Fig. 9; Fig. 11 is a partially exploded perspective view of the settable mechanism of the roller printing head in accordance with Fig. 9; and Fig. 12 is a cross-sectional view taken on line 12 - 12 in Fig. 10. Referring to Fig. 1, a central processing unit (abbreviated as CPU hereinafter) 10 basically comprises a main control program 101, a microprocessor main control module 102, a display interface circuit 103 connected to a monitor 14, a printer interface circuit 105 connected to a printer 12. In practice, if necessary, it may further comprise a weighing scale interface circuit 104 connected to a weighing scale 11, an asynchronous interface circuit 106 connected to a payment system 13, a host interface circuit 107 connected to a modem 15A as well as a remote host 15, and a driver/sensor module interface circuit 108. The CPU 10 is electrically connected to a parallel bus interface circuit 20 through a parallel bus. The parallel bus interface circuit 20 comprises a sensor circuit 21 and a driver circuit 24. The sensor circuit 20 includes a keyboard interface circuit 22 connected to a keyboard 221 and a driver index interface circuit 23. The driver circuit 24 includes a first driver circuit 25, connected to a conveying driver 251 and an auxiliary driver 252, and a second driver circuit 25A. The second driver circuit 25A electrically connected to a main driver 256, a first wheel driver 253A, a second wheel driver 253B,... and an Nth wheel driver 253N. The driver index interface circuit 23 electrically connected to a first wheel driver indexer 231, a second wheel driver indexer 232, an Nth wheel driver indexer 233, etc., a main driver indexer 234, a conveying driver indexer 235 and an auxiliary driver indexer 236. For the purpose of understanding the operation of the present invention, postal material will be processed, as an example, by the system of the present invention. When postal material is disposed on an electronic weighing scale 11 before entering the system of this invention, its weight can be displayed on the screen of the CRT 14 by the CPU 10. In the meantime, the CPU 10 can accept instructions input from the keyboard 221 through the keyboard interface circuit 22. The CPU 10 then calculates the proper postage based on the available data and displays it on the screen of the CRT 14. The customer can then pay for the postage by inserting a specially-designed card in the payment system 13 or by some other device for inserting coins, whereby the CPU 10 will actuate the first driver circuit 25 and the second driver circuit 25A through the driver circuit 24, and consequently activate the conveying driver 251 and auxiliary drier 252 to move and bring the postal material to a proper position for printing. At this moment, the wheel drivers 253A, 253B,... 253N are also actuated and rotate their respective numerical wheels. The CPU 10 instructs each of the wheel drivers to rotate a certain angle in cooperation with the data from the respective wheel driver indexer 231, 232, 233, etc., until each desired number is respectively attained and then she CPU 10 activates the first driver circuit 25 and second driver circuit 25A thereby rotating the main driver 256 and postmarking and imprinting the date and postage on the postal material. Furthermore, the main driver 256 is restored to its home position for the next working cycle by sensing the main driver indexer 234. Turning now to Fig. 2, a first embodiment of this invention is shown. The device includes a conveying system 250 and a postmark printing system 27 wherein the conveying system 250 is arranged above and below a conveying reference surface A1, including a main driving means of the conveying system, for example a stepper motor 251 driving a first roller 2512 and a second roller 2513 through timing belts 2510 and 2511 respectively. Referring to Figs. 8A and 8B, installed is an idle roller 2514 with a stretching spring above the first roller 2512, and an idle roller 2515 above the second roller 2513. The postmark printing system is shown in Figs. 3 and 4, including a main shaft driving means, e.g. second stepper motor 256, pulleys 2561, 2563, a timing belt 2562, a main shaft 2505, on which a plurality of second racks 2504 are slidably mounted, a plurality of stepper motors 253A,... 253N for driving their respective numeral wheels 271, 272 through their respective related gears 253A4... 253N4, ink-printing means 40, a printing head 27, and an idle roller 2516 thereof (see Figs. 2, 3, 4, 8A and 8B). The printing head 27, as seen in Fig. 3, includes a postmark wheel means 271 for imprinting postage, a postmark wheel means 272 for imprinting accepted date, and a graphical postmark means 273 for imprinting advertising marks. Referring to Fig. 4, the postmark wheel means 271 further comprises a numeral wheel 2711, a gear 2712 attached therewith, a first rack 2713 engaged with the gear 2712, a guiding bar 2714 for the rack 2713 to move thereon, and a hooking arm 2715. The lower end of the hooking arm is secured to a recess 2506 of a second rack 2504. In order to restore the main shaft 2505 to its home position after the completion of postmarking, an encoder 234A and a main driver indexer 234 are disposed near the driving portion of the second stepper motor 256. Similarly, in order to assure that the stepper motor 253A properly drives the corresponding character wheel 2711, an encoder 253A1 and a first wheel driver indexer 231 are disposed thereon. Prior to the entering of postal material into the conveying system, the printing head 27 is zeroed to its home position (not shown) wherein a motor 251 is the prime driving source of the conveying system. As shown in Figs. 8A and 8B, disposed between the first roller 2512 and printing head 27 is a phototransistor conveying driver indexer 235 whereby after postal material 10 passes through the indexer 235, the CPU 10 will actuate the printing head 27. Below the printing head 27 is a third idle wheel 2516 with stretching spring in order that the postal material 10 be in close contact with the numeral wheel 271 of the printing head 27, as shown in Fig. 8B. As to the ink applied to the numeral wheel 271, it will be applied by a printing ink means 40, as shown in Figs. 8A and 8B. An ink wheel 41 is secured to a spring 42 and kept apart for a small gap from the printing head 27 by an adjusting screw 43 so that only when the protruding part of the numeral wheel passes by will the ink wheel 41 have proper contact therewith. During each cycle of operation, the printing head 27 will, driven by a solenoid 48 and a pump 44, cause the ink wheel 41 to be provided with suitable amount of ink. As can be seen in Fig. 8B, when the postal material 10 is advanced to be printed by the printing head 27, due to the spring effect of the first, second, and third idle wheels 2514, 2515, 2516, the printing effect is equal regardless of the thickness of the printed postal material. This is an advantage of the present invention over prior art. The disclosure thus far is related only to a printing head with one numeral wheel. In practical operation, however, the device works with four numeral wheels, or more than four numeral wheels arranged as two or more parallel sets, wherein one set functions as date numeral wheel, and the other as postal charge numeral wheel, as shown in Figs. 2 and 3. Various arrangements between a plurality of stepper motors 253A - 253F and their related second racks 2504A - 2504F for each set of character wheels are shown in Figs. 5, 6 and 7, respectively. As seen from Fig. 5, four stepper motors 253A - 253D are disposed within a square frame. Two sets in this arrangement will drive eight numeral wheels 271. Similarly, ten character wheels and twelve character wheels may also be driven by a pair of five and six stepper motors arranged as illustrated in Figs. 6 and 7, respectively. As can be understood, more character wheels can be arranged as necessary. A relatively smaller diameter portion 2505B of the main shaft 2505 of the printing head is located near the driving gear 253A4, as shown in Fig. 4. As will be seen from the drawing, the outer perimeter of the relatively smaller diameter portion 2505B, comes flush with the dented base 2502 of the second rack 2504, so that after respective stepper motors 253A - 253N are located at their proper positions and the main shaft 2505 of the printing head rotates, the second racks 2504 and the relatively smaller diamter portions 2505B can dip through the driving gear 253A4. In other words, the second rack 2504 for driving the character wheels of the printing head 27 can slide axially along the main shaft 2505, and also can rotate together with the main shaft 2505 after reaching its proper position, thus easing the work of the printing head 27 and reducing the very complicated mechanism needed in the prior art. This is a further important advantage of the present invention. Another embodiment of the present invention is shown in Figs. 9 to 12. The numeral wheel driving means includes a stepper motor 252 and a coupler shaft 2521, the coupler shaft 2521 connecting the stepper motor 252 to a screw rod 2523 to make the screw rod 2523 rotate together with the stepper motor 252. A screw block 2522 is rotatably mounted on the screw rod 2523, and a solenoid seat 314 is further installed on the screw block 2522 (as shown in Fig. 10). Numeral wheel drivers 253A - 253N are disposed on both sides of the solenoid seat 314. The numeral wheel drivers are plural solenoids 253A, 253B,... 253N which can extend or retract their piston rod according to commands from CPU to engage with or disengage from the second racks 2504 for setting the corresponding numeral wheels 271A, 271B,... 271N (as shown in Figs. 9, 10 and 12). As shown in Fig. 10, when driving means driving circuit 25 activates the stepper motor 252 to rotate clockwise, urging the solenoid seat 314 to move forward (as indicated by arrow A), the solenoid 253N will extend its piston rod into dents 2502 of the second rack 2504 in proper position thus moving the second rack 2504 forward until it is signalled to stop by a CPU pulse signal. Therefore, the numeral wheel 271N is rotated to a desired numeral position. For example, when "2" is the desired numeral in numeral wheel 271, the solenoid 253A will keep its shaft pin in a retracted state and move together with the solenoid seat 314. When it reaches the 11th dent 2502 of the second rack 2504, the solenoid 253A will now extend its piston rod into the 11th dent, urging the second rack 2504 to drive the numeral wheel 271 from "1" to "2". Other numeral positions can be acquired in a similar manner. The numeral wheel can be driven in another manner. When "2" is the desired numeral, the solenoid 253A can extend its piston rod into the first dent 2502 of the second rack 2504 at the beginning, and then move together with the solenoid seat 314 to make the second rack 2504 move forward. When the solenoid 253A moves to the original position of the second dent, it then retracts its piston rod and stays that way until the end position. Therefore, the numeral wheel 271 is driven from "1" to "2" by the second rack 2504. Other numerals can be achieved by a similar way. In reverse, when the numeral wheel 271 is to return to its original position, the solenoids 253 all retract their piston rods and the stepper motor 252 rotates counterclockwise to move the solenoid seat 314 back to the home position, whereby the solenoid 253 can urge against the projections 2503 at the end of the second racks 2504 to bring the second racks 2504 as well as all numeral wheels back to their home positions for next working cycle. Referring to Fig. 9, a coaxial pulley 2573 is disposed between the pulleys 2572 and 2574, whereby through pulleys 2571, 2572, 2573 and belts 2510A, 2561, the motor 251 of the conveying means can drive the shaft 2563 of the brake clutch 2564 of the main shaft driving means 256. When postal material 10 moves through a location sensing means (not shown), the solenoid 234 of the brake clutch 2564 (see Fig. 9) is activated to rotate the shaft 2565 of the brake clutch 2564 for one turn and stop the shaft 2565 in its original position. Accordingly, the driving gear 2566 to which the shaft 2565 connects rotates and urges another driving gear 2567 to rotate. As a result, through the shaft 2565, the printing head 27 is rotated for one turn and stopped where it was, whereby the postal material is imprinted between the printing head 27 and the idle roller 2516 disposed thereunder and carried away by conveying pulley 2513 and idle roller 2515. Then, the motor 251 of the conveying means is instructed to stop. As various possible embodiments might be made without departing from the invention as defined by the claims, it is to be understood that all matter herein described or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Claims: A digital mark-printer comprising: a central processing unit (CPU) (10) including a main control program (101) having a micro-processor main control module (102); a parallel bus (120); a parallel bus interface circuit means (20) connected to said central processing unit (10) through said parallel bus (120), including a sensor circuit means (21) and a driver circuit means (24); said sensor circuit means (21) including a keyboard interface circuit means (22) and a driver index interface circuit means (23); said driver circuit means (24) including a first driver circuit means (25) and a second driver circuit means (25A); a main shaft (2505) including a printing head (27) having a plurality of numeral wheel means (271), driven by said first and second driver circuit means (25, 25A) and said driver index interface circuit means (23); the main shaft (2505) further including; a plurality of gears (2712) concentrically attached to the plurality of numeral wheels (2711); a plurality of first racks (2713) geared with said plurality of gears (2712), each first rack (2713) having a hook arm member (2715); a plurality of guiding bars (2714) on which said hook arm members (2715) slide; and a plurality of second racks (2504) having a plurality of recesses (2506), one end of each recess being secured to a corresponding hook arm member (2715); a wheel driver means (253) including a plurality of stepper motors (253A-N) each having a driving gear means (253A4-N4), said main shaft (2505) having smaller diameter portions near said gear means (253A4-N4), said wheel driver means (253), engaged with second racks (2504) for driving said second racks (2504), driving said hook arms (2715) of said first racks (2713), and driving said numeral wheels (2711) according to commands from said CPU(10); the outer perimeter of the smaller diameter portions of the main shaft (2505) flushes with dent bases of the second racks (2504), so that after respective stepper motors (253A-N) are located at their proper positions and the main shaft (2505) of the printing head (27) rotates, the second racks (2504) and the portions of the main shaft (2505) can slip through the driving gears (253A4) to allow rotation of the main shaft (2505) without obstruction during a print cycle. A digital mark-printer comprising: a central processing unit (CPU) (10) including a main control program (101) having a micro-processor main control module (102); a parallel bus (120); a parallel bus interface circuit means (20) connected to said central processing unit (10) through said parallel bus (120), including a sensor circuit means (20) and a driver circuit means (24); said sensor circuit means (20) including a keyboard interface circuit means (22) and a driver index interface circuit means (23); said driver circuit means (24) including a first driver circuit means (25) and a second driver circuit means (25A); a main shaft (2505) including a printing head (27) having a plurality of numeral wheel means (271), driven by said first and second driver circuit means (25, 25A) and said driver index interface circuit means (23); the main shaft (2505) further including; a plurality of gears (2712) concentrically attached to the plurality of numeral wheels (2711); a plurality of first racks (2713) geared with said plurality of gears (2712), each first rack (2713) having a hook arm member (2715); a plurality of guiding bars (2714) on which said hook arm members (2715) slide; and a plurality of second racks (2504) having a plurality of recesses (2506), one end of each recess being secured to a corresponding hook arm member (2715); said wheel driver means (253) including a stepper motor (252), a corresponding coupler shaft (2521) associated with said stepper motor (252), a screw rod (2523) coaxially connected to said coupler shaft (2521), a screw block (2522) mounted on said screw rod (2533), a set of solenoid seats (314) installed on said screw block (2522), and a plurality of solenoids (253A-N) disposed on both sides of each of said solenoid seats (314), said solenoids (253A-N) each having a piston rod (2533A-N) which can be extended into or retracted from dents (2502) of said second rack (2504) for urging said second rack (2504) to drive said numeral wheel (2711) according to commands from said CPU (10), wherein when said driver circuit means (25) activates said stepper motor (252) to rotate and urge said solenoid seats (314) to move forward via said coupler shaft (2521), screw rod (2523) and screw block (2522), said solenoids (253A-N) extending their piston rod (2533A-N) into or retract their piston rod (2533A-N) from the dents (2502) of said second racks (2504) according to commands from said CPU (10) to move said second racks (2504) for setting said numeral wheels (2711) to desired positions. A digital mark-printer as claimed in claim 1 or 2, wherein: said conveying driver means included: a first belt (2510, 2511); a first pulley (2512); a second pulley connected to said first pulley (2512) by said first belt (2511); a first stepper motor (251) for driving said first pulley (2512); a first idle pulley (2514) in peripheral contact with said first pulley (2512) to provide for frictional conveying force; a second idle pulley (2515) in peripheral contact with said second pulley (2513) to provide for frictional conveying force; and said main shaft driver means includes: a second belt (2562); a third pulley (2561); a fourth pulley (2563) connected to said third pulley (2561) by said second belt (2562) and coaxially engaged with said main shaft (2505); and a second stepper motor (256) for driving said third pulley (2561) and consequently driving said main shaft (2503) to rotate for one cycle and then restore to its home position for a next working cycle. A digital mark-printer as claimed in any of the claims 1 to 3, wherein said sensor circuit means (22) further includes: a set of slotted disks (234A) and a read-out well (234) used to restore said main shaft (2505) and said wheel driver means to their home positions upon completion of a working cycle.

Inventors: WU SHENG-JUNG, WU, SHENG-JUNG
Applicants: WU SHENG JUNG, WU, SHENG-JUNG
Application year: 1990
Main classification: G07B17
IPC codes: G07B17