CA1056443A - Synchronizing control apparatus for electrophotographic apparatus utilizing digital computer - Google Patents
Synchronizing control apparatus for electrophotographic apparatus utilizing digital computerInfo
- Publication number
- CA1056443A CA1056443A CA210,239A CA210239A CA1056443A CA 1056443 A CA1056443 A CA 1056443A CA 210239 A CA210239 A CA 210239A CA 1056443 A CA1056443 A CA 1056443A
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- Prior art keywords
- recording element
- path
- processing stations
- along
- web
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-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
- G03G21/14—Electronic sequencing control
- G03G21/145—Electronic sequencing control wherein control pulses are generated by the mechanical movement of parts of the machine, e.g. the photoconductor
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Control Or Security For Electrophotography (AREA)
- Combination Of More Than One Step In Electrophotography (AREA)
- Controlling Sheets Or Webs (AREA)
- Controlling Rewinding, Feeding, Winding, Or Abnormalities Of Webs (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The recording element of an electrophotograpic copier is provided with a plurality of equally spaced timing marks or other indicia along one edge thereof.
Sensing means, positioned adjacent to the path along which the recording element is advanced during the electro-photographic copying process, act to sense the passage of the marks and to generate signals from which the position of each image area of the recording element can be accurately determined. The output signals from the sensing means are fed to a logic and control apparatus (e.g. a programmed digital computer) which controls the activation of the various processing stations in timed relation with the receipt of signals.
The recording element of an electrophotograpic copier is provided with a plurality of equally spaced timing marks or other indicia along one edge thereof.
Sensing means, positioned adjacent to the path along which the recording element is advanced during the electro-photographic copying process, act to sense the passage of the marks and to generate signals from which the position of each image area of the recording element can be accurately determined. The output signals from the sensing means are fed to a logic and control apparatus (e.g. a programmed digital computer) which controls the activation of the various processing stations in timed relation with the receipt of signals.
Description
BACKGROU~ O~ IIIE IN~'ENTION
-This invention relates to apparatus for controlling the operation of the various processing stations of eLectro~
photographic copying apparatus.
In a common form of electrophotographic copying apparatus, a toner image of an information medium, such as a document, is formed on a photoconductive recording element, and then transferred to a paper copy sheet. To initially form the toner ima~e on the recording element, the latter is transported along a path past a plurality of processing stations, each of which is selectively operable to perform one of the steps of the electrophotographic copying process. Such stations include:
a charging station at which a.uniform charge is deposited on the photoconductive surface of the recording element; an ex-posure station at which the charged photoconductive surface is imagewise exposed to actinic radiation from the medium to create an electrostatic image of the medium in the recording element;
a developing station at which the electrostatic image is con-tacted with finely divided charged markin~ particles (i.e.
toner) to render the electrostatic image visible; a transfer station at which a copy sheet is advanced into contact with the toner-bearing surface of the recording element to transfer the toner particles, in image configuration, to the copy sheet; and a cleaning station at which residual toner is removed from the surface of the recording element so that the recording element may be recycled through the electrophotographic process.
In electrophotographic apparatus which process the recording element automatically, it is necessary to precisely control the activation and the deactivation of the various proces-sing stations in timed relation with the movement of the recording element. Otherwise, the copy sheet, for instance, couLd be advanced to the transfer station before or after the toner image arrives thereat, the result being imperfect registration of the transferred toner image with the edges of the co~y sheet. To provide such contrd, it is, of course, necessary that the control device be continuously updated on the precise position of the recording element during its travel along the path past the processing stations.
In applications in which the recording element is continually recycled, it is typically constructed in the form of a drum or an endless web. When in a drum configur-ation, the recording element is mounted for rotation on a driven shaft, and synchronization of the operation of the various processing stations with movement of the drum is commonly controlled by a bank of cams which also rotate~, with the drive shaft. Because both the recording element and the cam bank are fixedly mounted on the drive shaft, the position of each cam always reflects the precise posi-tion of the recording element. Thus, synchronizing the actuation of the proce.ssing stations is straight for-ward. However, when the recording element is an endless web configuration, such synchronization is not as simple.
When in a web configuration, the recording element is trained about a plurality of spaced rollers and is driven by either a sprocket or a friction drive mechanism.
By using a sprocket drive, it is relatively simple to correlate the position of the recording element with the angular position of the sprocket drive shaft as long as there is substantially no slippage between the sprocket and the web. However, in any sprocket drive, there is atendency ~ -2-,;............................. ~
:-. , : ,. . .
~OS6443 f`or the driving sprocket to eventually tear or enlarge the web perforations whjch it drivingly engages. As the web perforations enlarge, control of -the position of the recording element diminishes because there is a slippage between the driving sprocket and the web. While the friction drive approach has little tendency to tear -2a-the web, there is even more of a tendency for the web to slip relative to the roll by which it is frictionally engaged and driven. Thus, the position of the shaft of the drive roll cannot be correlated with web position and, hence, cannot be used to synchronize the operation of the various processing stations.
One approach to the above problem has been to place a timing mark on one edge of the recording element and to use the mark to generate a signal to activate a cam bank, which operates independently of the web movement to control the operation of the processing stations. See, for instance U.S. Patent No. 3,606,532. In essence, this approach pro-vides the processing station control apparatus with an update of the web position at the start of each copy cycle,A disadvantage of this approach, however, is that registra-tion problems will still exist if there is any slippage be-tween the web and the friction drive after initiation of the timing cycle by the timing mark. Also, when the web defines several frame areas, a separate cam bank and multiple switch arrangement is needed for each frame area of the web. Such a complex electro-mechanical control system is subject to reliability problems.
SUMMARY OF THE INVENTION
An object of the invention, therefore is to provide an improved method and apparatus for synchronizing the actuation of the various processing stations which comprise an electrophotographic copying apparatus with the movement of the recording element.
~ -3-~05649~3 According to a preferred embodiment of the invention, one edge of the recording element of an electrophotographic copier is provided with indicia, such as a plurality of perforations, which serve as timing marks. Sensing means, fixed,ly positioned adjacent the path along which the record-ing element is advanced, sense the passage of the indicia and produce clock -3a-:, :
. . .
10564~3 pulses in response thereto. Such clock pulses provide a logic and control unit, preferably including a digital Compu1ter which is programmed to actuate the various pro-cessing stations according to a predetermined sequence, with :Lnformation from which it accurately determines the position and rate of movement of the image frame of the recording element. Using this position information, the logic and control unit synchronizes the operation of the various processing stations with the movement of the record-ing element along its path.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure l is an illustration of an electrophotographic copying apparatus embodying the invention;
Figure 2 is a partial perspective view showing in detail a portion of the photoconductive recording element of the Fig. l apparatus;
Figure 3 is a block diagram of the various components of the logic and control unit shown in Figure l;
Figure 4 is a diagram which shows the timing cycle ;;
of the appara~us shown in Figure l.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
To better understand the present invention, the operation of an electrophotographic copier embodying the invention will be briefly described. It is to be under-stood, however, that the apparatusof the present invention could be used with equal facility and advantage in ~t~er copying machines and, therefore, the following description of apparatusrelated to, but not forming a part of, the . ~ , . . . . .. .
lOS6~43 invention is provided f`or illustrative purposes only.
Elect:rophoto,~raphic Apparatus Reference is now made to Figure 1 wherein an electro-photographic copier embodying the invention is schematically illustrated. As shown, the copier includes a reusable photo-conductive recording element 10 which is in the form of an -4a-~05~443 endless web 16. 'I`he recording element is a multi-layer structure, including a conductive layer disposed between a photocondllctive layer and a transparen-t support. Pre-ferably, the conductive layer is transparent to permit exposure of the pho-toconductive layer from both sides thereof. Means (not shown) are provided for electrically grounding the conductive layer. The photoconductive layer may be formed from, for instance, a heterogeneous photo-conductive composition of the type disclosed in U.S.
Patent 3,615,414 issued October 24, 1971.
Web 16 is trained about transport rollers 4-9, at least one of which is continupusly rotatably driven to frictionally engage the transparent support of web 16 to continuously advance the web in a clockwise direction, as viewed in Figure 1. The dimensions of web 16 define several image areas or frames which are spacedly arranged side-by-side. The splice by which web 16 is rendered end-less is, by means of the control apparatus of the invention, always maintained at an interframe position so as not to interfere with and degrade image formation and quality.
, Arranged at fixed locations adjacent to the path along which recording element 10 is advanced are the various processihg s*ations which collectively serve to form a transferable toner image on the various image areas of the recording element. Such stations include: a changing station 18, at which a uniform charge is deposited on the photo-conductive layer of recording element 10 to initiate the copying process; an exposure station 20 at which the uni-~/ .
~ _5_ ~056443 formly charged surface of the recording element is image-wise exposed to an information medium 13, such as a document, to selectively dissipate the charge on the recording element and thereby form a latent electrostatic image of the information medium; and a developing station 22 at which electroscopic toner particles are applied to the recording element to render visible the electrostatic image borne thereby. Also positioned adjacent the path of the re-cording elcment arç: a transfer station 24 at which the developedimage is transferred in imagewise confi~uration to a paper copy sheet, and a cleaning station 17 which serves to remove residuaL toner particles from the recording element following transfer. In addition to the above stations, more details of which are provided hereinbelow, the copying apparatus in-cludes an auxiliary erase lamp 33 which, when actuated, flood exposes the photoconductive layer of the web to dissipate and thereby prevent development of, any undesired charge pro-duced on the recording element during the initial start-up or shut-down of the copier, and a post development erase lamp 23 which, when actuated, serves to flood expose the photoconductive -~
layer of the recording element immediately after development to reduce photoconductor "fatigue" and to facilitate transfer of the toner image.
In addition to those processing stations physically positioned adjacent to the path of the recording element, the copying apparat~s also includes a pair of copy sheet fee~ing stations 21 and 27, a registration station~l9 at which a copy sheet advanced from stations 21 or 27 is placed in registration with a toner image advancing toward the transfer station 24, and a fusing station 30 at which the transferred toner image is permanently fixed to the copy sheet.
` Although not shown, charging station 18 typically comprises a corona generator, such as disclosed in the commonly assigned U.S. patpRt 3,527,941. Charging station 18 operates under the control of a logic and control unit 9, hereinafter referred to as the "LCU", as do all other stations and accessories of the copying apparatus. Control of station 18 by the LCU is effected via lead 18a.
Exposure station 20 preferably comprises a pair of se~ectively energizable xenon flash lamps 14 which are arranged parallel to one another outs~ e opposing edges of the information 1~)56443 m~dium 13. When energized by the LCU via leads 14a. lamps 14 momentarily illuminate the information medium and image there-of is projected by lens 15 upon the uniformly charged photo-conductive surface of web 16. Because of the intense output of lamps 14 imagewise exposure of web 16 is accomplished "on the fly", i.e. without stopping the web. As will become more apparent from the description of the LCU, the LCU is capable of storing inormation concerning the total number of copies produced by the copying apparatus. Due to this capability and other features of the LCU discussed below, the LCU can be used to periodically increase the output power of the flash lamp to compensate for any loss of photocond~ tor speed with usage of the web.
Developing station 22 may comprise a double magnetic brush apparatus, such as disclosed in the commonly assigned U.S. Patent 3,543,720, issued to Drexler et al. LCU 9 can be used to automatically controL the electrical bias of the magnetic brushes, which acS às development electrodes, in accordance with thé charge density in the background areas of the electrostatic image. Sensing o~ such charge density may be effected by positioning a metal plate (not shown) adjacent to the web path, upstream ~rom the developing station, monitoring the charge induced thereon, and feeding a signal proportional thereto to the LCU. The LCU can properly bias the magnetic brushes via lead 22a. Alternatively, the bias level can be ... .
manually set through the LCU.
~ ransfer station 24 may comprise,as shown, a pair of corona generators 25 and 26. Corona generator 25 acts to charge the paper copy sheet so as to render it attractive to the toner image. Assuming the toner particles are initially charged to a positive polarity so as to be attracted to the negative charge deposited by the primary charger 18,then the corona generator 25 should be powered by a negative D.C.
105fi443 power supply. Cororla generator 26 is known as a "detacking corona" and serves to neutralize the electrostatic forces bonding the copy sheet to the web 16 following image trans-fer. As shown the detacking corona is powered by a positively biased A.C. power supply. LCU control o$ both power supplies of the transfer station is effected via lead 25a.
Following transfer of the toner image to a copy sheet, the latter is stripped from web 16 as the web bends sharply over small transport roll 8. Vacuum transport 29 delivers the copy sheet to the nip of a roller fusing device 30 which comprises an internally heated fusing roll 30c which selectively cooperates with a pressure roll 30b. The latter is movable into engagement with fusing roll 30c in response to a signal provided by the LCU on lead 30à.
After fusing, the copy sheet follows either of the paths labeled 31 or 32 in exiting from the machine to either a hopper 34 or a copy handling accessory 36, such as a sorter. LCU 9 can be used to control the path followed by the copy sheet via a signal applied to lead 36a which controls a movable deflector plate in the paper path.
Cleaning station 17 may include an erase lamp, D.C.-biased A.C. corona and a vacuum cleaner (see Fig. 4), all of which operate under the control of the control apparatus of the invention.
As mentioned above, the various processing stations of the Fig. 1 apparatus , in addition to the other components of the copying apparatus discussed hereinbelow, are selec-tively activated by and operate under the control of logic and control unit 9. 'I`his unit, the LCU, preferablyincludes a digital computer 74 (see Fig. 2) -8a-, lOS6443 which is programmed to control the operation of the various work stations according to a predetermined sequence and in timed relation with the receipt of signals indicative of the rate of' movement and the instantaneous position of the recording element. Such signals are generated by trans-ducers 76a and 76b which are fixedly arranged rel~ative to ' the web path and which sense indicia carried by the record-ing element, preferably in the form of perforations. These signals provide the computer with up-to-date information (which may also appropriately be called "real time" informa-tion) regarding the precise location of each image area of the recording element, and are used by the computer to determine when certain work activit,~es should commence and terminate. The output of the LCU selectively controls such activities accordingly. The manner in which the LCU derives position information from the recording element and uses such information to control the operation of the various work stations is described in detail below.
R ordin~_Element As mentioned above, the length of web 16 is such as to~ enable a plurality of copies, such as six, to be made each time the web is cycled through the electrophotographic process. Assuming web 16 defines six image or frame areas, this means that each frame area occupies approximately a degree se~ment of the web. Actually, each frame area is slightly less than 60 degrees to allow for a small inter-frame area.
As shown in Fig. 2, one edge of web 16 is provided with two parallel rows of equally spaced indicia, shown as _g_ ~ . . .
~5t~443 perforations 16a and 16b. Perforations 15a and 16b are hereinafter occasionally referred to as "F" and "C"
perfs, respectively.
-9a~
: " " . - ' ~ .' `
105~443 I`he number of F perfs on the web exactly equals the number of frame areas, and each F perf is located at a predetermined posi1ion with regard to each frame area. As will be seen below, each F perf cooperates with transducer 76a to pr~vide the l.CU with information regarding the position of the leading edge of all the image areas on the recording element.
Also, it is the F perf which signals the LCU to initiate flash exposure and to feed a copy sheet to the transfer station 24. The C perfs, in effect, finely divide each frame area of the web into a plurality of increments, for instance, fifty-one. As will be seen below, the C perfs cooperate with transducer 76b to provide the LCU with clock pulses from which it determines web speed, and hence, frame position after it departs from the exposure station. As will be seen below, the LCU comprises counting means (e.g.
a shift register) for counting incoming F and C perf signals and means for actuating the various stations in response to a predetermined F and C perf count. Each time an F perf is received by the LCU, the C perf is reset to zero.
Electromechanical Transducers As shown in Figs. 1 and 2, the copying apparatus includes a pair of electromechanical transducers 76a and 76b which are fixedly arranged relative to web 16 to sense the passage of the F and C perfs, respectively. Transducers 76a and 76b are commonly referred to as "bimorph sensors".
Bimorph sensors which are suitable for use in the present invention are described in commonly assigned U.S.
Patent 3,723,650 in the name of Bradley et al, issued March 27, 1973. Briefly, each bimorph sensor includes a piezoele-ctrical crystal -10-. ~.. . . .
~os~43 82 which hcls attclched thereto a single step sensor 83element, the distcll end 84 of which bears on and slides against the moving web member 16. When a perforation in the web member 16 moves beneath the distal end of the sensor element, the end abruptly drops over the leading edge of the perforation and distorts or otherwise induces nechanical movement of its associated transducer. As the web member 16 continues to move the sensor element 83 is foreced out of the perforation by engagement with the trailing edge of the perforation, and once again the sensor element distorts its associated piezoelectric trans-ducer. By means of electrodes or other suitable current collecting means attached to the sensors, voltage signals generated by the distortion of the transducer are trans-mitted to the computer 74. Other types of perforation sen-sors which produce output signals such as optical perfora-tion sensors or other types of ceramic transducers respon-sive to compression, bending or other forms of physical distortion, may be substituted for the depicted bimorph sensors.
Logic and Control Unit Turning now to Fig. 3, there is shown in block diagram form the Logic and Control Unit which interfaces with the various processing stations and the bimorph sensors.
As indicated above the LCU preferably comprises a program-mable digital computer 74. The LCU could, however, be hardwired logic circuitry which would include shift regis-ters, counters and decoding matrixes. An example of such hardwired logic which could be adapted for use with the pre-sent structure is shown in commonly assigned U.S. Patent3,732,005 to Lloyd. In such patent, -105t;443 there is disclosed a control apparatus for an electrophoto-graphic machine which in response to clock pulses timed from the motor drive shaft of such machine produces control signals for actuating and deactuating work stations in timed relation to movement of the web. Ihe disclosed apparatus includes counters and decoding matrixes. However, it has been determined, in accordance with the invention, that a miniature digital computer is especially adaptable to provide the functions of the LCU mentioned above, in addi-tion to other copier functions. For instance a computer can periodically interrogate a toner concentration moni-toring device and actuate a toner replenishing mechanism atan appropriate time. Further, it can be used to periodically interrogate paper jam and misfeed detectors in the copy machine and shut down the machine if necessary. Further, it can monitor the number of copies made, compare this number with the number of copies requested and inactivate the machine at the appropriate time. Various other func-tions which the computer may serve are discussed later herein.
Computer 74 may take various forms known in the art, some of which are commercially available as programmable mini-computers and programmable micro-processors. The Model 8080 Micro Computer manufactured by Intel Corporation of Santa Clara, California is an example of a suitable micro-processor. The GEPAC 30, manufactured by the General Electric Corporation; the Interdate Model I and the Varian Data Machine Model 520/i are specific examples of suitable mini-computers. The instructions and methods of programming such devices is set forth in the textbook, "Mini-Computers for Engineers and Scientists", by ravin~ ~. Korn, publishcd by Mc~raw ~lill Book Company, (1973).
Microprocessors are similar to mini-computers, but there are some basic differences. For instance, a micro-processor, unlike a mini-computer, is generally fabricated with only one or a small number of inte~rated circuits. Moreover, it does not have a very high computing storage memory and, hence, is relatively inexpensive. ~lowever, its speed is fast enough to make it entirely suitable for controlling all work operations of a very high speed electrophotographic apparatus. As is well known, the current microprocessors require a read and write memory (RAM), for data storage; a read only memory (ROM), for program storage; and circuits for obtaining access to the apparatus under the control of the microprocessor. It is becoming quite common to convert all the hard-wired logic I functions into programs whi~h are stored in the ROM. The ,, functions disclosed by the hard-wired logic in the above-referenced Lloyd disclosure all can be performed by a micro-~ processor.
With respect to the Intel microprocessor, Model 8080, such a device operates on a word size of one byte or eight bits and has an instruction time of between two and six microseconds, and used a memory size of 65,536 bytes. The number of in-structions which implement such microprocessor is 48; and it ~` has interrupt capability, address models of operation, and five 8-bit registers in addition to a program control register and an unlimited stack. The above-discussed RAM and ROM are stand-ard with this unit. More particularly, the Intel 8080 contains instructions registers, local memory, arithmetic output and input-output buffers. Of course, there are a number of other , suitable microprocessors.
..
..
105~443 out of the most popular is Intel 4004 microprocessor. This microprocessor contains f`ive functional stations, address register and stack with an address-incrementing circuit, a set of 16 four-bit arithmetic and logic unit, and eight-bit instruction register and decoder and peripheral circuitry.
The following material discloses how to translate hard-wired logic into microprocessor sequences: John B.
Peatman, "Design of Digital Systems," pp. 211-216 and secs.
6-6, 6-7, McGraw-Hill Book Co., 1972; "MCS-4 Microcomputer Set User's Manual," Intel Corp., July 1972; and "8080, 8-bit Parallel Central Processor Unit", Intel Corp., November 1972.
As shown in Fig. 3, computer 74 comprises a temporary data storage memory 90, a central processing unit 92, a timing and cycle control unit 94, and a stored control program 96. The temporary data storage memory stores such information as the number of copies requested for each maching operation, the total number of copies made by a - .-particular recording element, etc. Some of the information stored by memory(j90 need only to be stored for one machine operation. The number of copies requested is exemplary of such information. Other information stored by memory 90 must be stored for several machine operations. The total number of copies produces by a particular recording element is exemplary of this type of information. Thus, the tempo-rary data storage memory includes both a volatile and a non-volatile Read/Write Memory (RAM). The control program 96 may be embodied by a commercially available Read Only Memory (ROM). The ROM would contain the operational ' , .
, ,: , 10~64~3 progrRm in the fonm of instructions and fixed binary numbers corrcsponding to numeric constants. Such programs are permanently stored in the ROM and, of course, cannot be altered by computer operation. Preferably, the ROM is programmed at the point of manufacture and the instructions programmed provide the required control functions such as sequential sctuation of the processing stations, jam recovery, operator observable logic and machine timing. For a specific example, the total ROM
capacity could be approximately 5,000 words, with each word being 8 bits in length. Data input to the computer and the computer output is performed sequentially according to the control program.
Input d~ta from the bimorph sensors is fed to the central processing unit through an interrupt signal processor 104 (dis-closed below). Other input signals such as the output signals of a toner monitoring device, paper misfeed sensors, copy count sensors, are applied to the central processing unit through an input signal buffer 100 and a multiplexe~. The output data and oontrol signals are applied to storage latches 106 (e.g. con-ventional flip-flops) which provide inputs to suitable output drivers 10~ directly coupled to the Ieads for the processing station. More specifically, the output signals rom the LCU are logic level, digital signals which are buffered and amplified to provide drive signals to various clutches, brakes, solenoids, power switches and numeric displays of the copying apparatus.
The LCU processing functions can be progra~ned by merely changing the instructions stored in the computer memory. This provides a flexible machine logic and timing arrangement and extends the 105f~443 LC~' capabilit~ to include the capacity for perfor~ing service diagnostics.
(omputer Interrupt ~ s noted above, -the lC~ controls, by a counting technique, -the copying cycle and activates the processing stations which perform the required operation in the processing of each active and inactive image area on the web. Also noted, is the fact that the mechanism for selecting the appropriate input signal processing technique is a program stored in the LCU computer. Since the computer 74 cannot operate on all inputs and outputs simultaneously, a technique for selecting those signals to be processed, during each phase of the copy cycle, has been developed. Again, the F perf and C perf are the key factors to selecting the appropriate control programs. As mentioned above, the F perf and C perf signals are counted and stored in the memory 90 of the LCU computer. The location of active and inactive image areas along the web path can be determined from the F perf and C perf count.
Thus, those signals critical to the process, that should be occurring at any particular count in the cycle, can be selected for processing by the LCU. Other none critical signals are processed periodically, when the LCU is not required to recognize a C perf or F perf signal. The C
perf and F perf signals override other inputs to the LCU
computer, by interrupting the computer; thus, the occur-rence of these signals is always detected by the LCU. The use of a computer interrupt is well known in the computer art. For a complete explanation of this technique, see the above-referenced test, "Mini-Computers for Engineers and Scientists."
--16_ 105t~443 Operation As indicated above, proper sequencing of machine control signals is critical to the production of high quality copies and to prevent paper misfeeds, misregis-tration and erratic operation. The primary approach for controlling the timed sequence of events and their relationship to each other is, as noted above, to sense -~
the location of the image areas of the web as they contin-ually cycle, and to synchronize the various control J mechanisms with the movement of the image areas. The ~`
technique for accomplishing this, as previously noted, is to sense equally spaced perforations formed in the edge of web 16, such perforations occupying a known position relative to each irnage area. The web member, as noted above, is preferably divided into 6 image frames, each designated by an F perf, and the space between each F
perf is subdivided into 51 increments by 51 C perfs.
Machine sequencing control is implemented in the LCU by converting signal timing and combinational logic require-ments to programs that control the LCU computer. These control programs establish the basic operating mode and sequence of events for the machine subsystems.
The electrophotographic cycle is initiated by actua-tion of switches on a conventional operator's control panel (not shown). The appropriate switch on the panel may be selected for one or two-sided copying. The LCU 9 accepts input signals from the operator's panel, sotres the signals in the compu-ter memory 90, and decodes the signals to sel-ect the program which will initiate and control the electro-photographic cycle. In addition to selecting a machineoperating -17_ , ~ . , ~05~443 mode, the operator input panel is also used to select a quantity of copies. I`his information, also stored in the LCll computer memory 9Q, is compared to the quantity of copies completed during the cycling of the machine. Upon delivery of the requested number of copies, the LCU develops output signals to deactivate the copying mode.
During the copying cycle, the F and C perf signals pro-vided by the bimorph sensors are the primary control signal inputs to the LCU, and provide the synchronizing signals for the control of events. The LCU computer counts F perfs and C perfs and stores this information, together with fixed data, (e.g. the maximum number of active image ele-ments and the distance between adjacent C perfs on the web). The LCU computer determines where each active and inactive image element is with respect to the F perf sensor. This information is combined with knowledge of the spacing between various processing stations along the web path to develop control signals which activate these pro-cessing stations at the required point in the cycle. Thus, the speed of web 16 need not be precisely known. The length of web 16, the spacing between perforations, and the location of the processing stations relative to the F perf sensor must be known and fixed.
Reference is now made to Fig. 4 wherein a typical copy cycle consi$ting of a single copy is used to illus-trate when, during the movement of the recording element certain events occur, and the duration of such occurrences.
The angular spacing of the various processing stations shown in Fig. 4 is equivalent to the linear spacing between such stations in the Fig. 1 apparatus. The film path is represented . .
~OSt~443 by the inner ircular path of the annulus of Fig. 4. It is assumed that web 16 defines six image areas, each sub-tending an arc or approximately 60 degrees. Actually, each image area subtends an arc of slightly less than 60 degrees to allow for an interframe spacing, one of which includes the splice in the recording element. Because of its six image areas, web 16 is provided with six equally spaced F perfs, each occupying the same location with regard to its associated image area. The area between each F perf is subdivided, as noted above, by 51 C perfs, thus dividing the entire recording element into a total of 606 increments. The letters A - J are used to indicate the location at which various events occur as the leading edge of an image area passes such locations during its clockwise movement around the endless path. The signals developed by the LCU computer during the copy cycle are indicated in timed sequence in Table I. As shown in Table I, as the leading edge of the image frame passes position A, certain processing stations are turned ON.
These include those stations which remain ON throughout the copying cycle, as well as those whch are only required for the initial portion of the copying cycle. The system components which remain ON continuously include the post-development erase lamp 23 and the various components of the cleaning station 17 which, as shown, may include an erase lamp, a corona and a cleaning vacuum. As the re-cording element passes point B, the C perf count stored by memory 90 is reset to zero by the F perf pulse. From this point on, all events are controlled simply by counting a specific number of F and C perfs and controlling the 3~ -19-.
105~443 events according to the number of F and C perf`s counted, and whether or not the requested number of copies has bee!n made.
-19a-TAB~E
SEQUENCE OF EVENTS FOR SINGLE COPY RUN
FILM POSITION
.
A START Switch Actuated System Operate ON
Primary Charger ON
Auxiliary Erase Lamp ON
B Reset C Perforation Count to Zerc.
C Illumination Power Supply "Initiated" ::
~ D Flash Exposure : .
E Auxiliary Erase Lamp OFF
Monitor Enable ON
F Auxiliary Erase Lamp ON
primar~ Charger OFF
~ G .Paper Feed .~` . .
H Transfer Charger ON
: Detact Charger ON
: ' .
: I Transfer Charger OFF
. Detact Charger OFF
' . .
STOP
System Operate OFF
Auxiliary Erase Lamp OFF
.
~5~443 Table II illustrates the infor~lat ion stored in the LCU during a multiple-copy cycle. A Run 1ip-Elop and a PRINT flip-flop, although not shown, will be unders~ood ~o be ~ocated in the central processing unit 92 o the computer 7~. These flip-flops are actuated and, as shown in Table IX, are switched to a logical "1" by depressing the START button.
When the stored C count first reaches 51 and an F perforation is detected, the ~CU stores a logical 1 in a five-bit shi~t register disposed in the processor 92 which counts and stores the number of F perforations sensed. At the same time as when the third F perforation signal ls fed to the five-bit shit register, ~ first binary signal is sellt to an 8-bit paper shift register. At this time, the computer not only causes an image of a document to be exposed on the web, but also causes a first copy sheet to be fed to the transfer station. Thus, three "F"
perf signals must be ~ensed before a developed toner image area is disposed adjacent the transfer station. The 8-bit shift register, of course, counts and stores the number of copy sheets fed. As shown in Table II, i ten or more copies are to be made, both shit registers will become ~ull. The machine will continue to imagewise expose the recording element until the number of copies requested equals the number stored in the 'copies requested"counter (in Table II, it is ten). At this time, a time-out cycle will commence, causing the PRINT flip-flop to be reset to a zero state. In this state, further exposure of the recording element is inhibited. During the time-out cycle, successive F perforations signals clear the ' 105f~443 shifts registers as indicated in the table. As successive F perforations are detected, copy sheets are fed into the transfer station. At the end of the cycle, the machine is set in a stand-by mode.
." , . .
_22-10564~3 T~B~
SEQUENCE OF EVENTS FOR MULTIPLE COPY, ONE-SIDE COPY MODE
RUN PRINT SHIFTSHIFT C F
FLIP-FLOP FLIP-FLOP REGISTER REGISTER COUNT COUNT
.
St~rt 1 1 O O any O
. 1 1 0001100000000 51 2 0011100000001 51. 3 .
1 1111111111111 . 51 10 .. . .
O 11000 11111110 . 51 . 13 O 00000 11111000. 15 lOS6443 Miseellall~o!ls LCU F~lnctiolls .
In addition to controlling the operation of the various processing stations, the LCU computer 74 can be used, with suitable sensing elements, to detect copy sheet jams and copy sheet misfeeds.
Paper Jam and Misfeed Lo~ic The paper path is shown iQ Figure 1. As discussed with ~spect to the timing diagram (Figure 4), the paper feeding is initiated by the LCU 9. Paper registration is accomplished by mechanical means and is controlled by the registration mechanism 19. A number of sensors may be located along the paper path to detect paper feeding or mis-feeds and produce signals to the LCU at properly selected positions. These signals may include (1) leading edge detector in the paper feed mechanism, (2) transfer jam detector, (3) side exit/top exit jam detectors, (4) sorter jam detection. The jam signals are monitored by the LCU
computer and in the event of a paper jam, the computer 74 is programmed to develop control signals for a machine shut-down with indication-to the operator to check the paper path.
The machine jam ~tection logic incorporates signal sensing and control which reduces the potential of mechanism damage caused by a paper jam.
In the copying mode, the flow of paper from the supply to the exits under nominal conditions is completely predictable. The time between ini~iation of paper feed and the arrival of paper at any of these paper sensing switcllcs can be expressed in terms of film perforation signals (F ar~d C perfs.). The film per~oration signal count is stored in the computer and at designated perforation count in~ervals, the paper sensing switches are interrogated. If paper has not arrived at the sensing switch within the nominal perforation count interval, a jam is detected.
Likewise, if paper has not cleared a switch within a specified perforation count interval, a jam is indicated. It should be noted that the paper jam detection is not based on time measurement. It is based on perforation counting by the computer, i.e. the flow of paper through the machine is ex-pressed in terms of perforation counts.
If a copy sheet is not fed from the paper supplies 21 and 27, the failure is classed as a "misfeed". This failure need not result in a machine shutdown. If a single misfeed occurs, the computer 74 adjusts the paper shift register contents to account for the loss of one copy in the control logic. If two consecutive misfeeds occur, the paper in the paper path completes the transition through the printed to an exit and the machine is shut down. The number of copies processed and delivered is stored in the LCU computer 74 and a check paper path indicator is turned ON. The operator would normally clear the misfeed sheets and restart the copy cycle. Since the delivered count is stored during the misfeed recovery, the cycle restarts where it left off and the number of copies required to complete the run are delivered to the exit.
: .
While the invention has been disclosed with particular reference to preferred embodiments, it should be apparent that many modifications can be made to the apparatus and method disclosed without substantially departing from the spirit of the invention. For instance, while particular reference has been made to a recording element in the form of an endless flexible web, it should be apparent that the invention would have utility with any recording element format, including drum and open-ended webs. The inventive concept 10is to use indicia on the recording element, regardless of its format, to continuously update the control mechanism s which selectively actuates the processing stations with the position of each active area of the recording element as it moves along its predetermined path. Also, while reference has been made to a recording element comprising six image areas, each identified by a F perf and subdivided by 51 C perfs, it should be apparent that these numbers merely are illustrative of a preferred recording element. Obviously, the more C perfs, the more precise the recording element 20position can be determined. Preferably, however, the number of C perfs should exceed 20 per image area on the recording element.
.. . . .
.. . . .
-This invention relates to apparatus for controlling the operation of the various processing stations of eLectro~
photographic copying apparatus.
In a common form of electrophotographic copying apparatus, a toner image of an information medium, such as a document, is formed on a photoconductive recording element, and then transferred to a paper copy sheet. To initially form the toner ima~e on the recording element, the latter is transported along a path past a plurality of processing stations, each of which is selectively operable to perform one of the steps of the electrophotographic copying process. Such stations include:
a charging station at which a.uniform charge is deposited on the photoconductive surface of the recording element; an ex-posure station at which the charged photoconductive surface is imagewise exposed to actinic radiation from the medium to create an electrostatic image of the medium in the recording element;
a developing station at which the electrostatic image is con-tacted with finely divided charged markin~ particles (i.e.
toner) to render the electrostatic image visible; a transfer station at which a copy sheet is advanced into contact with the toner-bearing surface of the recording element to transfer the toner particles, in image configuration, to the copy sheet; and a cleaning station at which residual toner is removed from the surface of the recording element so that the recording element may be recycled through the electrophotographic process.
In electrophotographic apparatus which process the recording element automatically, it is necessary to precisely control the activation and the deactivation of the various proces-sing stations in timed relation with the movement of the recording element. Otherwise, the copy sheet, for instance, couLd be advanced to the transfer station before or after the toner image arrives thereat, the result being imperfect registration of the transferred toner image with the edges of the co~y sheet. To provide such contrd, it is, of course, necessary that the control device be continuously updated on the precise position of the recording element during its travel along the path past the processing stations.
In applications in which the recording element is continually recycled, it is typically constructed in the form of a drum or an endless web. When in a drum configur-ation, the recording element is mounted for rotation on a driven shaft, and synchronization of the operation of the various processing stations with movement of the drum is commonly controlled by a bank of cams which also rotate~, with the drive shaft. Because both the recording element and the cam bank are fixedly mounted on the drive shaft, the position of each cam always reflects the precise posi-tion of the recording element. Thus, synchronizing the actuation of the proce.ssing stations is straight for-ward. However, when the recording element is an endless web configuration, such synchronization is not as simple.
When in a web configuration, the recording element is trained about a plurality of spaced rollers and is driven by either a sprocket or a friction drive mechanism.
By using a sprocket drive, it is relatively simple to correlate the position of the recording element with the angular position of the sprocket drive shaft as long as there is substantially no slippage between the sprocket and the web. However, in any sprocket drive, there is atendency ~ -2-,;............................. ~
:-. , : ,. . .
~OS6443 f`or the driving sprocket to eventually tear or enlarge the web perforations whjch it drivingly engages. As the web perforations enlarge, control of -the position of the recording element diminishes because there is a slippage between the driving sprocket and the web. While the friction drive approach has little tendency to tear -2a-the web, there is even more of a tendency for the web to slip relative to the roll by which it is frictionally engaged and driven. Thus, the position of the shaft of the drive roll cannot be correlated with web position and, hence, cannot be used to synchronize the operation of the various processing stations.
One approach to the above problem has been to place a timing mark on one edge of the recording element and to use the mark to generate a signal to activate a cam bank, which operates independently of the web movement to control the operation of the processing stations. See, for instance U.S. Patent No. 3,606,532. In essence, this approach pro-vides the processing station control apparatus with an update of the web position at the start of each copy cycle,A disadvantage of this approach, however, is that registra-tion problems will still exist if there is any slippage be-tween the web and the friction drive after initiation of the timing cycle by the timing mark. Also, when the web defines several frame areas, a separate cam bank and multiple switch arrangement is needed for each frame area of the web. Such a complex electro-mechanical control system is subject to reliability problems.
SUMMARY OF THE INVENTION
An object of the invention, therefore is to provide an improved method and apparatus for synchronizing the actuation of the various processing stations which comprise an electrophotographic copying apparatus with the movement of the recording element.
~ -3-~05649~3 According to a preferred embodiment of the invention, one edge of the recording element of an electrophotographic copier is provided with indicia, such as a plurality of perforations, which serve as timing marks. Sensing means, fixed,ly positioned adjacent the path along which the record-ing element is advanced, sense the passage of the indicia and produce clock -3a-:, :
. . .
10564~3 pulses in response thereto. Such clock pulses provide a logic and control unit, preferably including a digital Compu1ter which is programmed to actuate the various pro-cessing stations according to a predetermined sequence, with :Lnformation from which it accurately determines the position and rate of movement of the image frame of the recording element. Using this position information, the logic and control unit synchronizes the operation of the various processing stations with the movement of the record-ing element along its path.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure l is an illustration of an electrophotographic copying apparatus embodying the invention;
Figure 2 is a partial perspective view showing in detail a portion of the photoconductive recording element of the Fig. l apparatus;
Figure 3 is a block diagram of the various components of the logic and control unit shown in Figure l;
Figure 4 is a diagram which shows the timing cycle ;;
of the appara~us shown in Figure l.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
To better understand the present invention, the operation of an electrophotographic copier embodying the invention will be briefly described. It is to be under-stood, however, that the apparatusof the present invention could be used with equal facility and advantage in ~t~er copying machines and, therefore, the following description of apparatusrelated to, but not forming a part of, the . ~ , . . . . .. .
lOS6~43 invention is provided f`or illustrative purposes only.
Elect:rophoto,~raphic Apparatus Reference is now made to Figure 1 wherein an electro-photographic copier embodying the invention is schematically illustrated. As shown, the copier includes a reusable photo-conductive recording element 10 which is in the form of an -4a-~05~443 endless web 16. 'I`he recording element is a multi-layer structure, including a conductive layer disposed between a photocondllctive layer and a transparen-t support. Pre-ferably, the conductive layer is transparent to permit exposure of the pho-toconductive layer from both sides thereof. Means (not shown) are provided for electrically grounding the conductive layer. The photoconductive layer may be formed from, for instance, a heterogeneous photo-conductive composition of the type disclosed in U.S.
Patent 3,615,414 issued October 24, 1971.
Web 16 is trained about transport rollers 4-9, at least one of which is continupusly rotatably driven to frictionally engage the transparent support of web 16 to continuously advance the web in a clockwise direction, as viewed in Figure 1. The dimensions of web 16 define several image areas or frames which are spacedly arranged side-by-side. The splice by which web 16 is rendered end-less is, by means of the control apparatus of the invention, always maintained at an interframe position so as not to interfere with and degrade image formation and quality.
, Arranged at fixed locations adjacent to the path along which recording element 10 is advanced are the various processihg s*ations which collectively serve to form a transferable toner image on the various image areas of the recording element. Such stations include: a changing station 18, at which a uniform charge is deposited on the photo-conductive layer of recording element 10 to initiate the copying process; an exposure station 20 at which the uni-~/ .
~ _5_ ~056443 formly charged surface of the recording element is image-wise exposed to an information medium 13, such as a document, to selectively dissipate the charge on the recording element and thereby form a latent electrostatic image of the information medium; and a developing station 22 at which electroscopic toner particles are applied to the recording element to render visible the electrostatic image borne thereby. Also positioned adjacent the path of the re-cording elcment arç: a transfer station 24 at which the developedimage is transferred in imagewise confi~uration to a paper copy sheet, and a cleaning station 17 which serves to remove residuaL toner particles from the recording element following transfer. In addition to the above stations, more details of which are provided hereinbelow, the copying apparatus in-cludes an auxiliary erase lamp 33 which, when actuated, flood exposes the photoconductive layer of the web to dissipate and thereby prevent development of, any undesired charge pro-duced on the recording element during the initial start-up or shut-down of the copier, and a post development erase lamp 23 which, when actuated, serves to flood expose the photoconductive -~
layer of the recording element immediately after development to reduce photoconductor "fatigue" and to facilitate transfer of the toner image.
In addition to those processing stations physically positioned adjacent to the path of the recording element, the copying apparat~s also includes a pair of copy sheet fee~ing stations 21 and 27, a registration station~l9 at which a copy sheet advanced from stations 21 or 27 is placed in registration with a toner image advancing toward the transfer station 24, and a fusing station 30 at which the transferred toner image is permanently fixed to the copy sheet.
` Although not shown, charging station 18 typically comprises a corona generator, such as disclosed in the commonly assigned U.S. patpRt 3,527,941. Charging station 18 operates under the control of a logic and control unit 9, hereinafter referred to as the "LCU", as do all other stations and accessories of the copying apparatus. Control of station 18 by the LCU is effected via lead 18a.
Exposure station 20 preferably comprises a pair of se~ectively energizable xenon flash lamps 14 which are arranged parallel to one another outs~ e opposing edges of the information 1~)56443 m~dium 13. When energized by the LCU via leads 14a. lamps 14 momentarily illuminate the information medium and image there-of is projected by lens 15 upon the uniformly charged photo-conductive surface of web 16. Because of the intense output of lamps 14 imagewise exposure of web 16 is accomplished "on the fly", i.e. without stopping the web. As will become more apparent from the description of the LCU, the LCU is capable of storing inormation concerning the total number of copies produced by the copying apparatus. Due to this capability and other features of the LCU discussed below, the LCU can be used to periodically increase the output power of the flash lamp to compensate for any loss of photocond~ tor speed with usage of the web.
Developing station 22 may comprise a double magnetic brush apparatus, such as disclosed in the commonly assigned U.S. Patent 3,543,720, issued to Drexler et al. LCU 9 can be used to automatically controL the electrical bias of the magnetic brushes, which acS às development electrodes, in accordance with thé charge density in the background areas of the electrostatic image. Sensing o~ such charge density may be effected by positioning a metal plate (not shown) adjacent to the web path, upstream ~rom the developing station, monitoring the charge induced thereon, and feeding a signal proportional thereto to the LCU. The LCU can properly bias the magnetic brushes via lead 22a. Alternatively, the bias level can be ... .
manually set through the LCU.
~ ransfer station 24 may comprise,as shown, a pair of corona generators 25 and 26. Corona generator 25 acts to charge the paper copy sheet so as to render it attractive to the toner image. Assuming the toner particles are initially charged to a positive polarity so as to be attracted to the negative charge deposited by the primary charger 18,then the corona generator 25 should be powered by a negative D.C.
105fi443 power supply. Cororla generator 26 is known as a "detacking corona" and serves to neutralize the electrostatic forces bonding the copy sheet to the web 16 following image trans-fer. As shown the detacking corona is powered by a positively biased A.C. power supply. LCU control o$ both power supplies of the transfer station is effected via lead 25a.
Following transfer of the toner image to a copy sheet, the latter is stripped from web 16 as the web bends sharply over small transport roll 8. Vacuum transport 29 delivers the copy sheet to the nip of a roller fusing device 30 which comprises an internally heated fusing roll 30c which selectively cooperates with a pressure roll 30b. The latter is movable into engagement with fusing roll 30c in response to a signal provided by the LCU on lead 30à.
After fusing, the copy sheet follows either of the paths labeled 31 or 32 in exiting from the machine to either a hopper 34 or a copy handling accessory 36, such as a sorter. LCU 9 can be used to control the path followed by the copy sheet via a signal applied to lead 36a which controls a movable deflector plate in the paper path.
Cleaning station 17 may include an erase lamp, D.C.-biased A.C. corona and a vacuum cleaner (see Fig. 4), all of which operate under the control of the control apparatus of the invention.
As mentioned above, the various processing stations of the Fig. 1 apparatus , in addition to the other components of the copying apparatus discussed hereinbelow, are selec-tively activated by and operate under the control of logic and control unit 9. 'I`his unit, the LCU, preferablyincludes a digital computer 74 (see Fig. 2) -8a-, lOS6443 which is programmed to control the operation of the various work stations according to a predetermined sequence and in timed relation with the receipt of signals indicative of the rate of' movement and the instantaneous position of the recording element. Such signals are generated by trans-ducers 76a and 76b which are fixedly arranged rel~ative to ' the web path and which sense indicia carried by the record-ing element, preferably in the form of perforations. These signals provide the computer with up-to-date information (which may also appropriately be called "real time" informa-tion) regarding the precise location of each image area of the recording element, and are used by the computer to determine when certain work activit,~es should commence and terminate. The output of the LCU selectively controls such activities accordingly. The manner in which the LCU derives position information from the recording element and uses such information to control the operation of the various work stations is described in detail below.
R ordin~_Element As mentioned above, the length of web 16 is such as to~ enable a plurality of copies, such as six, to be made each time the web is cycled through the electrophotographic process. Assuming web 16 defines six image or frame areas, this means that each frame area occupies approximately a degree se~ment of the web. Actually, each frame area is slightly less than 60 degrees to allow for a small inter-frame area.
As shown in Fig. 2, one edge of web 16 is provided with two parallel rows of equally spaced indicia, shown as _g_ ~ . . .
~5t~443 perforations 16a and 16b. Perforations 15a and 16b are hereinafter occasionally referred to as "F" and "C"
perfs, respectively.
-9a~
: " " . - ' ~ .' `
105~443 I`he number of F perfs on the web exactly equals the number of frame areas, and each F perf is located at a predetermined posi1ion with regard to each frame area. As will be seen below, each F perf cooperates with transducer 76a to pr~vide the l.CU with information regarding the position of the leading edge of all the image areas on the recording element.
Also, it is the F perf which signals the LCU to initiate flash exposure and to feed a copy sheet to the transfer station 24. The C perfs, in effect, finely divide each frame area of the web into a plurality of increments, for instance, fifty-one. As will be seen below, the C perfs cooperate with transducer 76b to provide the LCU with clock pulses from which it determines web speed, and hence, frame position after it departs from the exposure station. As will be seen below, the LCU comprises counting means (e.g.
a shift register) for counting incoming F and C perf signals and means for actuating the various stations in response to a predetermined F and C perf count. Each time an F perf is received by the LCU, the C perf is reset to zero.
Electromechanical Transducers As shown in Figs. 1 and 2, the copying apparatus includes a pair of electromechanical transducers 76a and 76b which are fixedly arranged relative to web 16 to sense the passage of the F and C perfs, respectively. Transducers 76a and 76b are commonly referred to as "bimorph sensors".
Bimorph sensors which are suitable for use in the present invention are described in commonly assigned U.S.
Patent 3,723,650 in the name of Bradley et al, issued March 27, 1973. Briefly, each bimorph sensor includes a piezoele-ctrical crystal -10-. ~.. . . .
~os~43 82 which hcls attclched thereto a single step sensor 83element, the distcll end 84 of which bears on and slides against the moving web member 16. When a perforation in the web member 16 moves beneath the distal end of the sensor element, the end abruptly drops over the leading edge of the perforation and distorts or otherwise induces nechanical movement of its associated transducer. As the web member 16 continues to move the sensor element 83 is foreced out of the perforation by engagement with the trailing edge of the perforation, and once again the sensor element distorts its associated piezoelectric trans-ducer. By means of electrodes or other suitable current collecting means attached to the sensors, voltage signals generated by the distortion of the transducer are trans-mitted to the computer 74. Other types of perforation sen-sors which produce output signals such as optical perfora-tion sensors or other types of ceramic transducers respon-sive to compression, bending or other forms of physical distortion, may be substituted for the depicted bimorph sensors.
Logic and Control Unit Turning now to Fig. 3, there is shown in block diagram form the Logic and Control Unit which interfaces with the various processing stations and the bimorph sensors.
As indicated above the LCU preferably comprises a program-mable digital computer 74. The LCU could, however, be hardwired logic circuitry which would include shift regis-ters, counters and decoding matrixes. An example of such hardwired logic which could be adapted for use with the pre-sent structure is shown in commonly assigned U.S. Patent3,732,005 to Lloyd. In such patent, -105t;443 there is disclosed a control apparatus for an electrophoto-graphic machine which in response to clock pulses timed from the motor drive shaft of such machine produces control signals for actuating and deactuating work stations in timed relation to movement of the web. Ihe disclosed apparatus includes counters and decoding matrixes. However, it has been determined, in accordance with the invention, that a miniature digital computer is especially adaptable to provide the functions of the LCU mentioned above, in addi-tion to other copier functions. For instance a computer can periodically interrogate a toner concentration moni-toring device and actuate a toner replenishing mechanism atan appropriate time. Further, it can be used to periodically interrogate paper jam and misfeed detectors in the copy machine and shut down the machine if necessary. Further, it can monitor the number of copies made, compare this number with the number of copies requested and inactivate the machine at the appropriate time. Various other func-tions which the computer may serve are discussed later herein.
Computer 74 may take various forms known in the art, some of which are commercially available as programmable mini-computers and programmable micro-processors. The Model 8080 Micro Computer manufactured by Intel Corporation of Santa Clara, California is an example of a suitable micro-processor. The GEPAC 30, manufactured by the General Electric Corporation; the Interdate Model I and the Varian Data Machine Model 520/i are specific examples of suitable mini-computers. The instructions and methods of programming such devices is set forth in the textbook, "Mini-Computers for Engineers and Scientists", by ravin~ ~. Korn, publishcd by Mc~raw ~lill Book Company, (1973).
Microprocessors are similar to mini-computers, but there are some basic differences. For instance, a micro-processor, unlike a mini-computer, is generally fabricated with only one or a small number of inte~rated circuits. Moreover, it does not have a very high computing storage memory and, hence, is relatively inexpensive. ~lowever, its speed is fast enough to make it entirely suitable for controlling all work operations of a very high speed electrophotographic apparatus. As is well known, the current microprocessors require a read and write memory (RAM), for data storage; a read only memory (ROM), for program storage; and circuits for obtaining access to the apparatus under the control of the microprocessor. It is becoming quite common to convert all the hard-wired logic I functions into programs whi~h are stored in the ROM. The ,, functions disclosed by the hard-wired logic in the above-referenced Lloyd disclosure all can be performed by a micro-~ processor.
With respect to the Intel microprocessor, Model 8080, such a device operates on a word size of one byte or eight bits and has an instruction time of between two and six microseconds, and used a memory size of 65,536 bytes. The number of in-structions which implement such microprocessor is 48; and it ~` has interrupt capability, address models of operation, and five 8-bit registers in addition to a program control register and an unlimited stack. The above-discussed RAM and ROM are stand-ard with this unit. More particularly, the Intel 8080 contains instructions registers, local memory, arithmetic output and input-output buffers. Of course, there are a number of other , suitable microprocessors.
..
..
105~443 out of the most popular is Intel 4004 microprocessor. This microprocessor contains f`ive functional stations, address register and stack with an address-incrementing circuit, a set of 16 four-bit arithmetic and logic unit, and eight-bit instruction register and decoder and peripheral circuitry.
The following material discloses how to translate hard-wired logic into microprocessor sequences: John B.
Peatman, "Design of Digital Systems," pp. 211-216 and secs.
6-6, 6-7, McGraw-Hill Book Co., 1972; "MCS-4 Microcomputer Set User's Manual," Intel Corp., July 1972; and "8080, 8-bit Parallel Central Processor Unit", Intel Corp., November 1972.
As shown in Fig. 3, computer 74 comprises a temporary data storage memory 90, a central processing unit 92, a timing and cycle control unit 94, and a stored control program 96. The temporary data storage memory stores such information as the number of copies requested for each maching operation, the total number of copies made by a - .-particular recording element, etc. Some of the information stored by memory(j90 need only to be stored for one machine operation. The number of copies requested is exemplary of such information. Other information stored by memory 90 must be stored for several machine operations. The total number of copies produces by a particular recording element is exemplary of this type of information. Thus, the tempo-rary data storage memory includes both a volatile and a non-volatile Read/Write Memory (RAM). The control program 96 may be embodied by a commercially available Read Only Memory (ROM). The ROM would contain the operational ' , .
, ,: , 10~64~3 progrRm in the fonm of instructions and fixed binary numbers corrcsponding to numeric constants. Such programs are permanently stored in the ROM and, of course, cannot be altered by computer operation. Preferably, the ROM is programmed at the point of manufacture and the instructions programmed provide the required control functions such as sequential sctuation of the processing stations, jam recovery, operator observable logic and machine timing. For a specific example, the total ROM
capacity could be approximately 5,000 words, with each word being 8 bits in length. Data input to the computer and the computer output is performed sequentially according to the control program.
Input d~ta from the bimorph sensors is fed to the central processing unit through an interrupt signal processor 104 (dis-closed below). Other input signals such as the output signals of a toner monitoring device, paper misfeed sensors, copy count sensors, are applied to the central processing unit through an input signal buffer 100 and a multiplexe~. The output data and oontrol signals are applied to storage latches 106 (e.g. con-ventional flip-flops) which provide inputs to suitable output drivers 10~ directly coupled to the Ieads for the processing station. More specifically, the output signals rom the LCU are logic level, digital signals which are buffered and amplified to provide drive signals to various clutches, brakes, solenoids, power switches and numeric displays of the copying apparatus.
The LCU processing functions can be progra~ned by merely changing the instructions stored in the computer memory. This provides a flexible machine logic and timing arrangement and extends the 105f~443 LC~' capabilit~ to include the capacity for perfor~ing service diagnostics.
(omputer Interrupt ~ s noted above, -the lC~ controls, by a counting technique, -the copying cycle and activates the processing stations which perform the required operation in the processing of each active and inactive image area on the web. Also noted, is the fact that the mechanism for selecting the appropriate input signal processing technique is a program stored in the LCU computer. Since the computer 74 cannot operate on all inputs and outputs simultaneously, a technique for selecting those signals to be processed, during each phase of the copy cycle, has been developed. Again, the F perf and C perf are the key factors to selecting the appropriate control programs. As mentioned above, the F perf and C perf signals are counted and stored in the memory 90 of the LCU computer. The location of active and inactive image areas along the web path can be determined from the F perf and C perf count.
Thus, those signals critical to the process, that should be occurring at any particular count in the cycle, can be selected for processing by the LCU. Other none critical signals are processed periodically, when the LCU is not required to recognize a C perf or F perf signal. The C
perf and F perf signals override other inputs to the LCU
computer, by interrupting the computer; thus, the occur-rence of these signals is always detected by the LCU. The use of a computer interrupt is well known in the computer art. For a complete explanation of this technique, see the above-referenced test, "Mini-Computers for Engineers and Scientists."
--16_ 105t~443 Operation As indicated above, proper sequencing of machine control signals is critical to the production of high quality copies and to prevent paper misfeeds, misregis-tration and erratic operation. The primary approach for controlling the timed sequence of events and their relationship to each other is, as noted above, to sense -~
the location of the image areas of the web as they contin-ually cycle, and to synchronize the various control J mechanisms with the movement of the image areas. The ~`
technique for accomplishing this, as previously noted, is to sense equally spaced perforations formed in the edge of web 16, such perforations occupying a known position relative to each irnage area. The web member, as noted above, is preferably divided into 6 image frames, each designated by an F perf, and the space between each F
perf is subdivided into 51 increments by 51 C perfs.
Machine sequencing control is implemented in the LCU by converting signal timing and combinational logic require-ments to programs that control the LCU computer. These control programs establish the basic operating mode and sequence of events for the machine subsystems.
The electrophotographic cycle is initiated by actua-tion of switches on a conventional operator's control panel (not shown). The appropriate switch on the panel may be selected for one or two-sided copying. The LCU 9 accepts input signals from the operator's panel, sotres the signals in the compu-ter memory 90, and decodes the signals to sel-ect the program which will initiate and control the electro-photographic cycle. In addition to selecting a machineoperating -17_ , ~ . , ~05~443 mode, the operator input panel is also used to select a quantity of copies. I`his information, also stored in the LCll computer memory 9Q, is compared to the quantity of copies completed during the cycling of the machine. Upon delivery of the requested number of copies, the LCU develops output signals to deactivate the copying mode.
During the copying cycle, the F and C perf signals pro-vided by the bimorph sensors are the primary control signal inputs to the LCU, and provide the synchronizing signals for the control of events. The LCU computer counts F perfs and C perfs and stores this information, together with fixed data, (e.g. the maximum number of active image ele-ments and the distance between adjacent C perfs on the web). The LCU computer determines where each active and inactive image element is with respect to the F perf sensor. This information is combined with knowledge of the spacing between various processing stations along the web path to develop control signals which activate these pro-cessing stations at the required point in the cycle. Thus, the speed of web 16 need not be precisely known. The length of web 16, the spacing between perforations, and the location of the processing stations relative to the F perf sensor must be known and fixed.
Reference is now made to Fig. 4 wherein a typical copy cycle consi$ting of a single copy is used to illus-trate when, during the movement of the recording element certain events occur, and the duration of such occurrences.
The angular spacing of the various processing stations shown in Fig. 4 is equivalent to the linear spacing between such stations in the Fig. 1 apparatus. The film path is represented . .
~OSt~443 by the inner ircular path of the annulus of Fig. 4. It is assumed that web 16 defines six image areas, each sub-tending an arc or approximately 60 degrees. Actually, each image area subtends an arc of slightly less than 60 degrees to allow for an interframe spacing, one of which includes the splice in the recording element. Because of its six image areas, web 16 is provided with six equally spaced F perfs, each occupying the same location with regard to its associated image area. The area between each F perf is subdivided, as noted above, by 51 C perfs, thus dividing the entire recording element into a total of 606 increments. The letters A - J are used to indicate the location at which various events occur as the leading edge of an image area passes such locations during its clockwise movement around the endless path. The signals developed by the LCU computer during the copy cycle are indicated in timed sequence in Table I. As shown in Table I, as the leading edge of the image frame passes position A, certain processing stations are turned ON.
These include those stations which remain ON throughout the copying cycle, as well as those whch are only required for the initial portion of the copying cycle. The system components which remain ON continuously include the post-development erase lamp 23 and the various components of the cleaning station 17 which, as shown, may include an erase lamp, a corona and a cleaning vacuum. As the re-cording element passes point B, the C perf count stored by memory 90 is reset to zero by the F perf pulse. From this point on, all events are controlled simply by counting a specific number of F and C perfs and controlling the 3~ -19-.
105~443 events according to the number of F and C perf`s counted, and whether or not the requested number of copies has bee!n made.
-19a-TAB~E
SEQUENCE OF EVENTS FOR SINGLE COPY RUN
FILM POSITION
.
A START Switch Actuated System Operate ON
Primary Charger ON
Auxiliary Erase Lamp ON
B Reset C Perforation Count to Zerc.
C Illumination Power Supply "Initiated" ::
~ D Flash Exposure : .
E Auxiliary Erase Lamp OFF
Monitor Enable ON
F Auxiliary Erase Lamp ON
primar~ Charger OFF
~ G .Paper Feed .~` . .
H Transfer Charger ON
: Detact Charger ON
: ' .
: I Transfer Charger OFF
. Detact Charger OFF
' . .
STOP
System Operate OFF
Auxiliary Erase Lamp OFF
.
~5~443 Table II illustrates the infor~lat ion stored in the LCU during a multiple-copy cycle. A Run 1ip-Elop and a PRINT flip-flop, although not shown, will be unders~ood ~o be ~ocated in the central processing unit 92 o the computer 7~. These flip-flops are actuated and, as shown in Table IX, are switched to a logical "1" by depressing the START button.
When the stored C count first reaches 51 and an F perforation is detected, the ~CU stores a logical 1 in a five-bit shi~t register disposed in the processor 92 which counts and stores the number of F perforations sensed. At the same time as when the third F perforation signal ls fed to the five-bit shit register, ~ first binary signal is sellt to an 8-bit paper shift register. At this time, the computer not only causes an image of a document to be exposed on the web, but also causes a first copy sheet to be fed to the transfer station. Thus, three "F"
perf signals must be ~ensed before a developed toner image area is disposed adjacent the transfer station. The 8-bit shift register, of course, counts and stores the number of copy sheets fed. As shown in Table II, i ten or more copies are to be made, both shit registers will become ~ull. The machine will continue to imagewise expose the recording element until the number of copies requested equals the number stored in the 'copies requested"counter (in Table II, it is ten). At this time, a time-out cycle will commence, causing the PRINT flip-flop to be reset to a zero state. In this state, further exposure of the recording element is inhibited. During the time-out cycle, successive F perforations signals clear the ' 105f~443 shifts registers as indicated in the table. As successive F perforations are detected, copy sheets are fed into the transfer station. At the end of the cycle, the machine is set in a stand-by mode.
." , . .
_22-10564~3 T~B~
SEQUENCE OF EVENTS FOR MULTIPLE COPY, ONE-SIDE COPY MODE
RUN PRINT SHIFTSHIFT C F
FLIP-FLOP FLIP-FLOP REGISTER REGISTER COUNT COUNT
.
St~rt 1 1 O O any O
. 1 1 0001100000000 51 2 0011100000001 51. 3 .
1 1111111111111 . 51 10 .. . .
O 11000 11111110 . 51 . 13 O 00000 11111000. 15 lOS6443 Miseellall~o!ls LCU F~lnctiolls .
In addition to controlling the operation of the various processing stations, the LCU computer 74 can be used, with suitable sensing elements, to detect copy sheet jams and copy sheet misfeeds.
Paper Jam and Misfeed Lo~ic The paper path is shown iQ Figure 1. As discussed with ~spect to the timing diagram (Figure 4), the paper feeding is initiated by the LCU 9. Paper registration is accomplished by mechanical means and is controlled by the registration mechanism 19. A number of sensors may be located along the paper path to detect paper feeding or mis-feeds and produce signals to the LCU at properly selected positions. These signals may include (1) leading edge detector in the paper feed mechanism, (2) transfer jam detector, (3) side exit/top exit jam detectors, (4) sorter jam detection. The jam signals are monitored by the LCU
computer and in the event of a paper jam, the computer 74 is programmed to develop control signals for a machine shut-down with indication-to the operator to check the paper path.
The machine jam ~tection logic incorporates signal sensing and control which reduces the potential of mechanism damage caused by a paper jam.
In the copying mode, the flow of paper from the supply to the exits under nominal conditions is completely predictable. The time between ini~iation of paper feed and the arrival of paper at any of these paper sensing switcllcs can be expressed in terms of film perforation signals (F ar~d C perfs.). The film per~oration signal count is stored in the computer and at designated perforation count in~ervals, the paper sensing switches are interrogated. If paper has not arrived at the sensing switch within the nominal perforation count interval, a jam is detected.
Likewise, if paper has not cleared a switch within a specified perforation count interval, a jam is indicated. It should be noted that the paper jam detection is not based on time measurement. It is based on perforation counting by the computer, i.e. the flow of paper through the machine is ex-pressed in terms of perforation counts.
If a copy sheet is not fed from the paper supplies 21 and 27, the failure is classed as a "misfeed". This failure need not result in a machine shutdown. If a single misfeed occurs, the computer 74 adjusts the paper shift register contents to account for the loss of one copy in the control logic. If two consecutive misfeeds occur, the paper in the paper path completes the transition through the printed to an exit and the machine is shut down. The number of copies processed and delivered is stored in the LCU computer 74 and a check paper path indicator is turned ON. The operator would normally clear the misfeed sheets and restart the copy cycle. Since the delivered count is stored during the misfeed recovery, the cycle restarts where it left off and the number of copies required to complete the run are delivered to the exit.
: .
While the invention has been disclosed with particular reference to preferred embodiments, it should be apparent that many modifications can be made to the apparatus and method disclosed without substantially departing from the spirit of the invention. For instance, while particular reference has been made to a recording element in the form of an endless flexible web, it should be apparent that the invention would have utility with any recording element format, including drum and open-ended webs. The inventive concept 10is to use indicia on the recording element, regardless of its format, to continuously update the control mechanism s which selectively actuates the processing stations with the position of each active area of the recording element as it moves along its predetermined path. Also, while reference has been made to a recording element comprising six image areas, each identified by a F perf and subdivided by 51 C perfs, it should be apparent that these numbers merely are illustrative of a preferred recording element. Obviously, the more C perfs, the more precise the recording element 20position can be determined. Preferably, however, the number of C perfs should exceed 20 per image area on the recording element.
.. . . .
.. . . .
Claims (13)
1. In an electrophotographic copier comprising a recording element having at least one photosensitive image area, means for advancing the recording element along a predetermined path past a plurality of processing stations which are spaced along such path and which sequentially act upon such image area to produce a visible image on the surface thereof, apparatus for selectively actuating the processing stations in timed relation with the movement of the image area to produce such image, said apparatus including:
(a) means defining a plurality of spaced timing indicia on the recording element, (b) first transducer means positioned adjacent such path and responsive to said timing indicia to generate clock pulses at a frequency proportional to the rate at which the recording element is advanced; and (c) logic and control means responsive to said clock pulses for selectively controlling the actuation of the processing stations in timed relation with the movement of the recording element
(a) means defining a plurality of spaced timing indicia on the recording element, (b) first transducer means positioned adjacent such path and responsive to said timing indicia to generate clock pulses at a frequency proportional to the rate at which the recording element is advanced; and (c) logic and control means responsive to said clock pulses for selectively controlling the actuation of the processing stations in timed relation with the movement of the recording element
2 The invention as set forth in Claim 1 wherein said timing indicia comprise means defining perforations in the recording element.
3. The invention as set forth in Claims 1 or 2 wherein said timing indicia are equally spaced and are arranged in a linear array along at least one edge of the recording element, said array being parallel to the path along which the recording element is advanced.
4. The invention as set forth in Claim 1 wherein said logic and control means comprises means for counting and storing the number of clock pulses and means responsive to the clock pulse count for selectively actuating selected processing stations in accordance with the clock pulse count.
5. The invention as set forth in Claim 4 wherein said counting means forms a part of a digital computer which is programmed to control the actuation of the processing stations according to a predetermined sequence, the rate at which said sequence is effected being determined by the rate at which said logic and control means receives clock pulses from said transducer means.
6. The invention as set forth in Claim 5 further comprising means for resetting the clock pulse count to zero after a predetermined number of timing indicia have been advanced past said transducer means.
7. The invention as set forth in Claim 6 wherein said resetting means comprises means defining an indicium on the recording element, and a second transducer means fixedly positioned adjacent the recording element path for sensing said indicium and for generating a reset signal in response thereto.
8. The invention as set forth in Claim 7 wherein said logic and control means further comprises means for counting and storing reset signals and means for selectively actuating selected processing stations in accordance with the reset signal count.
9. The invention as set forth in Claim 7 wherein the recording element comprises an endless photoconductive web which is adapted to have a plurality of images formed thereon at predetermined locations along the length thereof, and wherein each reset indicium occupies a predetermined pos-ition with respect to one of said image locations.
10. The invention as set forth in Claim 9 wherein said timing indicia and reset indicia are arranged in parallel linear arrays adjacent to one edge of said web.
11. The invention as set forth in Claim 4 wherein said copier further comprises means for advancing an image receiving member along a predefined path, at least a portion of which is substantially co-extensive with the recording element path, and said processing stations include a trans-fer station, positioned adjacent the co-extensive portions of the recording element and receiving member paths, for transferring said visible image from the recording element to the receiving sheet, and wherein said apparatus further includes a plurality of sensors positioned along the receiving member path for sensing the movement of the receiving member along such predefined path and for generating signals as the receiving element moves therepast, and wherein said logic and control means is responsive to said signals to permit continued operation of the copier so long as each of said signals is received by said logic and control means within a predetermined range in clock pulse count.
12. In an electrophotographic method for forming a toner image on an image area of an electrophotographic recording element, the improvement comprising:
(a) advancing a recording element having a plurality of spaced timing marks thereon along a predetermined path past a plurality of selectively actuatable processing stations;
(b) sensing the rate of movement of said timing marks past a fixed location along the path of the recording element;
(c) counting the number of timing marks sensed; and (d) selectively actuating selected processing stations in accordance with the number of timing marks counted.
(a) advancing a recording element having a plurality of spaced timing marks thereon along a predetermined path past a plurality of selectively actuatable processing stations;
(b) sensing the rate of movement of said timing marks past a fixed location along the path of the recording element;
(c) counting the number of timing marks sensed; and (d) selectively actuating selected processing stations in accordance with the number of timing marks counted.
13. The method of Claim 12 wherein the first step comprises advancing an endless photoconductive web along said path, said web having a plurality of image areas and first and second sets of perforations formed along at least one edge thereof for controlling the actuation of the processing stations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA313,194A CA1111490A (en) | 1973-10-01 | 1978-10-12 | Recording element for electrophotographic copier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US40222373A | 1973-10-01 | 1973-10-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1056443A true CA1056443A (en) | 1979-06-12 |
Family
ID=23591040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA210,239A Expired CA1056443A (en) | 1973-10-01 | 1974-09-27 | Synchronizing control apparatus for electrophotographic apparatus utilizing digital computer |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5733788B2 (en) |
| BE (1) | BE820601A (en) |
| CA (1) | CA1056443A (en) |
| CH (2) | CH588100A5 (en) |
| DE (1) | DE2446919C3 (en) |
| GB (2) | GB1483468A (en) |
| IT (1) | IT1022468B (en) |
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| JPS5230423A (en) * | 1975-09-03 | 1977-03-08 | Hitachi Ltd | Control device for copying machine |
| JPS5939742B2 (en) * | 1975-10-03 | 1984-09-26 | キヤノン株式会社 | Copy machine control device |
| DE2714481A1 (en) * | 1976-04-15 | 1978-01-12 | Xerox Corp | XEROGRAPHIC REPRODUCTION DEVICE WITH ERROR DETECTION SYSTEM |
| US4110032A (en) * | 1976-12-20 | 1978-08-29 | International Business Machines Corporation | Copy production machines having supply sheet pick retry |
| JPS53102745A (en) * | 1977-02-21 | 1978-09-07 | Ricoh Co Ltd | Correcting method of degrees of fatigue of photosensitive body of electrophotographic copying machine |
| JPS53108435A (en) * | 1977-03-04 | 1978-09-21 | Ricoh Co Ltd | Program control for compensating fatigue of photosensitive element of zeorgraphic apparatus |
| JPS6016622B2 (en) * | 1977-03-31 | 1985-04-26 | 株式会社リコー | Copy machine jam detection method |
| DE2858799C2 (en) * | 1977-04-06 | 1995-02-02 | Canon Kk | Electrostatic copier with microcomputer stored programme control |
| JPS53124437A (en) * | 1977-04-06 | 1978-10-30 | Canon Inc | Image former having computer |
| DE2814722C2 (en) * | 1977-04-06 | 1994-06-30 | Canon Kk | Printer or electrophotographic recorder |
| JPS53124438A (en) * | 1977-04-06 | 1978-10-30 | Canon Inc | Image former having computer |
| JPS53149037A (en) * | 1977-05-31 | 1978-12-26 | Canon Inc | Image forming system |
| JPS547329A (en) * | 1977-06-20 | 1979-01-20 | Ricoh Co Ltd | Input data erasing method in computer controlling of copying machines |
| JPS5410745A (en) * | 1977-06-27 | 1979-01-26 | Sharp Corp | Copying apparatus |
| JPS5429642A (en) * | 1977-08-10 | 1979-03-05 | Ricoh Co Ltd | Controlling system by multimicrocomputer system of copying machines |
| JPS5429641A (en) * | 1977-08-10 | 1979-03-05 | Ricoh Co Ltd | Control system by multimicrocompuer system of copying machines |
| US4196476A (en) * | 1977-08-30 | 1980-04-01 | Xerox Corporation | Reproduction machine with selectively disclosable programs |
| JPS5442149A (en) * | 1977-09-09 | 1979-04-03 | Canon Inc | Image former |
| JPS5445136A (en) * | 1977-09-17 | 1979-04-10 | Ricoh Co Ltd | Copying apparatus |
| JPS5449146A (en) * | 1977-09-27 | 1979-04-18 | Ricoh Co Ltd | Control method by multimicrocomputer system of copying machines |
| JPS5450329A (en) * | 1977-09-28 | 1979-04-20 | Ricoh Co Ltd | Copier control device using plural micro-computers |
| JPS5477882A (en) * | 1977-12-02 | 1979-06-21 | Canon Kk | Control device |
| JPS5512985A (en) * | 1979-01-26 | 1980-01-29 | Olympus Optical Co Ltd | Electrophotography device |
| JPS54137350A (en) * | 1978-04-18 | 1979-10-25 | Olympus Optical Co Ltd | Zerographic apparatus |
| JPS54143655A (en) * | 1978-04-28 | 1979-11-09 | Canon Inc | Method and apparatus for image forming |
| JPS5529864A (en) * | 1978-08-24 | 1980-03-03 | Canon Inc | Copying apparatus |
| JPS5529865A (en) * | 1978-08-24 | 1980-03-03 | Canon Inc | Copying apparatus |
| AU531958B2 (en) * | 1978-10-02 | 1983-09-15 | Tetras S.A. | Table top copy machine |
| JPS55108216U (en) * | 1979-01-23 | 1980-07-29 | ||
| JPS55100569A (en) * | 1979-01-26 | 1980-07-31 | Toshiba Corp | Control method of copying machine |
| JPS55164837A (en) * | 1979-06-08 | 1980-12-22 | Canon Inc | Copying apparatus |
| JPS5655871A (en) * | 1979-10-13 | 1981-05-16 | Canon Inc | Detecting device for electric potential |
| DE3038367C2 (en) * | 1979-10-13 | 1994-06-23 | Canon Kk | Electrophotographic device |
| JPS5655870A (en) * | 1979-10-13 | 1981-05-16 | Canon Inc | Detecting device for electric potential |
| JPS5666883A (en) * | 1979-11-05 | 1981-06-05 | Ricoh Co Ltd | Copying method |
| JPS56134042U (en) * | 1981-03-05 | 1981-10-12 | ||
| JPS5844452A (en) * | 1982-07-12 | 1983-03-15 | Canon Inc | Controlling method for image formation |
| JPS5824159A (en) * | 1982-07-13 | 1983-02-14 | Toshiba Corp | Electrophotographic copying machine |
| JPS5927857U (en) * | 1982-08-11 | 1984-02-21 | トヨタ自動車株式会社 | Impregnation treatment equipment |
| JPS58179857A (en) * | 1982-11-29 | 1983-10-21 | Canon Inc | Image forming device |
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| JPS58179866A (en) * | 1982-11-29 | 1983-10-21 | Canon Inc | Image forming device |
| JPS58130348A (en) * | 1982-12-27 | 1983-08-03 | Canon Inc | Controlling method of copying machine or the like |
| JPS58130349A (en) * | 1982-12-27 | 1983-08-03 | Canon Inc | Controlling method of copying machine or the like |
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| JPS6090360A (en) * | 1984-03-02 | 1985-05-21 | Canon Inc | Image forming device |
| JPS60156076A (en) * | 1984-03-02 | 1985-08-16 | Canon Inc | Image forming apparatus |
| JPS6090365A (en) * | 1984-03-02 | 1985-05-21 | Canon Inc | Image processing device |
| JPS6035756A (en) * | 1984-03-02 | 1985-02-23 | Canon Inc | Image forming device |
| JPS6063567A (en) * | 1984-04-06 | 1985-04-11 | Canon Inc | Image forming device having computer |
| JPS60136764A (en) * | 1984-05-31 | 1985-07-20 | Canon Inc | Image processor |
| JPS60136765A (en) * | 1984-05-31 | 1985-07-20 | Canon Inc | Image processor |
| JPS60136763A (en) * | 1984-05-31 | 1985-07-20 | Canon Inc | Image processor |
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| KR920007712B1 (en) * | 1987-06-15 | 1992-09-15 | 후지 제록스 가부시끼가이샤 | Recording apparatus |
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| US3700906A (en) * | 1970-03-16 | 1972-10-24 | Eastman Kodak Co | Magnetically controlled machine programmer |
| US3659109A (en) * | 1970-03-16 | 1972-04-25 | Eastman Kodak Co | Photosensitive controlled machine programmer |
| US3698805A (en) * | 1971-10-21 | 1972-10-17 | Eastman Kodak Co | Control apparatus for electrophotographic apparatus |
-
1974
- 1974-09-27 CA CA210,239A patent/CA1056443A/en not_active Expired
- 1974-09-30 CH CH1316974A patent/CH588100A5/xx not_active IP Right Cessation
- 1974-09-30 CH CH1316874A patent/CH588101A5/xx not_active IP Right Cessation
- 1974-09-30 IT IT2790274A patent/IT1022468B/en active
- 1974-10-01 GB GB4261174A patent/GB1483468A/en not_active Expired
- 1974-10-01 GB GB905277A patent/GB1483470A/en not_active Expired
- 1974-10-01 DE DE19742446919 patent/DE2446919C3/en not_active Expired
- 1974-10-01 BE BE149128A patent/BE820601A/en not_active IP Right Cessation
- 1974-10-01 JP JP11326574A patent/JPS5733788B2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5733788B2 (en) | 1982-07-19 |
| IT1022468B (en) | 1978-03-20 |
| DE2446919B2 (en) | 1978-12-21 |
| DE2446919C3 (en) | 1979-08-23 |
| CH588100A5 (en) | 1977-05-31 |
| CH588101A5 (en) | 1977-05-31 |
| GB1483468A (en) | 1977-08-17 |
| BE820601A (en) | 1975-04-01 |
| AU7379374A (en) | 1976-04-01 |
| GB1483470A (en) | 1977-08-17 |
| DE2446919A1 (en) | 1975-04-17 |
| JPS5062644A (en) | 1975-05-28 |
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