JPS6325668B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an image processing device. To explain an example of the copying process of a copying machine to which the present invention is applied, the surface of a photosensitive drum having a photosensitive member consisting of a conductive layer, a photoconductive layer, and an insulating layer is first charged by a primary charger as the drum rotates. The document is pre-charged (for example, positively charged), and then as the document table (or optical system) moves, an optical image is scanned and projected, and at the same time, the charge is removed by a recharger using alternating current (or direct current with the opposite polarity to the pre-charger). An electrostatic latent image is formed depending on the brightness of the optical image. Further, the latent image is entirely exposed to light to form a high-contrast electrostatic latent image, which is then made visible by a developer mainly containing toner in a developing device. Thereafter, the visible image is easily transferred by a corona discharge having the same polarity as the toner (for example, negative if the previous charge is positive), and is then transferred to plain paper, where it is fixed on a transfer machine by a heater while being conveyed. . On the other hand, developer such as colored particles remaining on the surface of the photosensitive drum after transfer is removed by a cleaning blade, and residual charges are removed by a lamp and a corona discharger, making it possible to repeat the photosensitive drum. By repeating the copying process as described above, a desired number of copies can be obtained. Among such devices, one is known in which the copying sequence is controlled by a microcomputer. Further, in order to always obtain stable images, there is a known device that detects when the amount of developer is running low and automatically replenishes it. However, since conventional recording agent control is executed independently of the copying sequence, for example, at the beginning of the operation of the developer motor, the detection of the concentration or amount of developer is unstable, resulting in Agent replenishment control may become unstable and malfunction. The present invention eliminates the above drawbacks and makes it possible to prevent malfunctions in developer replenishment control. The operation of an example of a copying machine according to the present invention will be explained below with reference to FIGS. 1 and 2. First, when the main switch 10 is turned on, it takes a short time (approximately 4 seconds here) to reset the digital control circuit and start up other electrical systems, and then rotates the photosensitive drum 15, which will be described later. A clock pulse generation mechanism is provided as part of the drive system to generate approximately 16 clock pulses. Therefore, when this photosensitive drum 15 starts rotating, it first receives 16 clock pulses (hereinafter referred to as
(written as 16CPetc), the drum rotates once or almost once. This can be considered a step before starting the copying process, and can be omitted in some cases to ensure that a high-quality copy is made when the copying process begins. Here, if the copy button 13 is turned on, the copying process will proceed directly. First, when you turn on copy button 13,
The photosensitive drum 15 rotates by 16 CP plus 3 CP, and then the document table 2 with the original placed on the document table glass 5 starts to be illuminated by the illumination lamp 16, and its image is transferred to the reflection mirror 17 and the in-mirror lens 18. As a result, an image is formed on the drum 15 at the exposure section 19. The photosensitive drum is equipped with a seamless photosensitive member on the circumference of the drum to increase the efficiency of surface use. The surface of the photosensitive drum 15, that is, the photosensitive layer covered with a transparent insulating layer, is first charged to + by a corona current from a positive charger 21 which supplies a high voltage of + from a high voltage power supply 20. Subsequently, when reaching the exposure section 19, the image of the subject illuminated by the illumination lamp 16 is slit-exposed onto the photosensitive drum 15, as described above. At the same time, from the high voltage power supply 20
AC high voltage is supplied. AC charging is performed by an AC charger 22. Then, a high-contrast electrostatic latent image is formed on the drum surface by full-face exposure using the full-face exposure lamp 23, and the next development process begins. The developing device 24 includes a container 26 in which a developer 25 is placed, a pump 27 that stirs the developer and pushes it up to the developing electrode section, a developing electrode 28, and, if there is a fog on the image developed on the drum, the fog is removed. Therefore, the electrostatic latent image formed on the photosensitive drum 15, which consists of an electrode roller 29 that rotates very close to the drum and one end of which is grounded, is caused by the developer being pushed up onto the developing electrode 28 by the pump 27. Developed with toner in 25.
Next, a post charger 30 receives a high voltage charge from a high voltage power source 20 and apertures excess developer on the photosensitive drum 15 without disturbing the image. Next, the transfer paper 7 fed from the paper feed section is brought into close contact with the photosensitive drum 15, and the image on the photosensitive drum 15 is transferred onto the transfer paper 7 by the electric field generated by the high voltage from the high power source 20 by the transfer charger 31. Ru. After the transfer, the transfer paper 7 is separated by a separation belt 32 and guided to a drying and fixing section 33. The remaining toner developer on the photosensitive drum 15 is wiped off by the edge portion 35 of the blade cleaner 34 that is pressed against it, and the next cycle is repeated again. The developer wiped with the blade cleaner 34 is applied to the photosensitive drum 1.
5 is guided to the developing device 24 through grooves 36 (FIG. 3) provided at both ends of the film, and is used again for development. Here, turn on the main switch 10 mentioned earlier, and the drum will rotate for an amount equivalent to 16 CP, and that 16 CP +
To explain why the document table 2 starts moving only after the drum has rotated by 3 CP, this machine uses an endless type photosensitive drum, and therefore no image can be formed on any surface of the photosensitive drum. We are now able to contribute to Therefore, if you want to increase the number of copies per hour by eliminating unnecessary rotations as much as possible, if some toner remains in the blade cleaner edge 35 during the first rotation of the drum, for example, In the worst case, the photosensitive drum may dry out and stick to the drum if it is not used for a week, and in that case, it is necessary to clean the photosensitive drum before forming a latent image. Next is 3CP, which is because there are 10 charging steps before the slit exposure in the copying process mentioned earlier, and the cleaner edge part mentioned above is added to the first copy. This process is based on the idea that avoiding this will make the machine more reliable. The transfer paper 7 is stored in a cassette 6, which is removably attached to a paper feed section at the lower left of the machine, and various types are prepared depending on the size of the transfer paper. When the document table reaches a predetermined position, an actuating piece 161 (FIG. 4) fixed to the document table activates the detection means on the main body side and outputs a signal, causing the constantly rotating paper feed roller 40 to operate. descends and comes into contact with the uppermost transfer paper in the cassette 6, and by movement with the separating claw 39, one transfer paper is separated and sent out from the cassette 6. However, the register rollers 41 and 42 in the immediate vicinity are the paper feed roller 40.
The transfer paper 7 is fed out from the cassette 6 and its leading edge touches the register roller 4.
The guides 43 and 4 are in contact with the contact parts of 1 and 42.
Create slack between 4. Then, when the paper feed roller is about to rise, the register rollers 41 and 42 are moved again at the leading edge of the image on the photosensitive drum.
rotates, and the transfer paper 7 is sent at a speed that matches the circumferential speed of the photosensitive drum 15. Next, the movement of the document table will be explained. Place the original to be copied on the original platen glass 5 with its leading edge aligned with the leading edge A of the glass, press it with the pusher cover 3 (Fig. 1), and press the copy button 13 (Fig. 1).
The drum starts rotating and starts working at the same time. The document table 2 moves to the left in FIG. 1 in synchronization with the circumferential speed of the photosensitive drum 15 in response to the document table start signal after 9CP from the clock pulse generating mechanism, and performs slit exposure. When the exposure is completed, the document table 2 stops moving to the left and immediately returns to the opposite direction, that is, to the right, in response to a signal from the document table 2 itself according to the size of the paper in the cassette. The time required for this return is loss time during copying, so it is desirable that it be short. In this machine, the return speed is approximately four times the forward speed to increase copying efficiency. Since the return speed is high as described above, a shock is likely to occur when stopping, but in this machine, the brake mechanism absorbs the shock and quickly stops the document table 2 at a predetermined position. A counting device (not shown) linked to the copy button 13 makes it easy to make multiple copies of the same document in succession. Restarting the document table during continuous copying is performed immediately after the document table 2 stops at a predetermined home position. The copy button is on the number of copies setting device (Figure 1)
The power will remain on until the number of sheets of copy paper set in is fed. Furthermore, the copying machine of this embodiment is capable of making copies of various sizes from the maximum B4 size to the minimum B5 size. In such a case, the document table 2 is the maximum copy size for any copy size.
If the machine were to travel a distance of B4, the number of copies per unit time would be small, resulting in a large time loss. Therefore, this copier supports various copy sizes (for example, A4,
B5) document platen reversal signal generating member 48A,
It has a plurality of B and C (Fig. 4), and the copying cycle is changed to correspond to each copying size, thereby increasing the copying efficiency. The above-mentioned differences in cycles depending on the copy size are determined by signals from the cassettes 6 for each size. Next, the suspension state and restart after copying is completed will be described. If the power is left on after all copying operations have been completed, the photosensitive drum 15 will constantly rotate, and if the high-voltage power is left on, this is not desirable in terms of the durability of the photosensitive drum 15 and the blade cleaner 34. . Therefore, in the copying machine of this embodiment, if a certain copying operation is completed and the next copying operation is not performed even after a certain period of time has passed, the drum will automatically stop and take a pause even if the main switch 10 is ON. It's starting to go into a state. This time is set longer than the time required for the transferred transfer paper 7 to be discharged outside the machine and for the entire surface of the photosensitive drum 15 to be cleaned. To perform copying during this pause state, press the copy button 13 of the operation unit 9, and everything will return to the state before the pause, the drum will rotate, and the document table 2 will begin to move forward after 9CP. Copy button 1 during this pause
When 3 is pressed, the high voltage power supply 20 is turned on and the photoreceptor 15 starts rotating. Before the copy button 13 is pressed, the potential on the photoreceptor 15 is maintained at a uniform potential by the AC static eliminator 22.
Press the next copy button 13 there - Charger 3
When the 0 and + transfer chargers 31 are inserted and the photoreceptor 15 begins to rotate, the space between the - charger 30 and the + transfer charger 31 is charged to +, and after the - charger, the potential is neutralized by the + charger 31. be harmonized. Therefore, there is an extreme potential difference on the photoreceptor 15 with the vicinity of the charger 30 as a boundary, and if this area enters the image forming area, it will have an adverse effect on the image. The distance from the AC static eliminator 22 where image formation begins to this charger 30 is converted into the number of clocks, and the number of clocks that does not affect the image is 9CP. FIG. 4 shows the drive system and signal generator. At the upper end of the rear frame 50 are members 73, 7 to which control signal magnetic sensing elements 48, 71, 72 are attached.
4 is fixed. (Figures 2 and 3) Magnetic detection elements 48 are installed on the guide rail mounting bases 73 and 74.
A, 71, 72, 48B, 48C are fixed and magnets 161, 162 are attached to the document table 2.
A control signal is issued sequentially by When the copy button is pressed and the document table 2 starts moving forward, the magnet 161 and the element 71 first issue a paper feeding command. Furthermore, the document table moves forward and each copy size (B5, A4, B4)
After the exposure of the magnet 161 is completed, the magnet 161
When reaching B or 48C, a reversal command is issued, and the document table 2 moves from forward movement to backward movement. The double movement progresses and magnet 1
When the document plate 62 reaches the element 72, a stop command causes the document table 2 to stop at a predetermined position. The size switching command is issued by the cassette 6. The clock pulse generation mechanism is the main motor _M1
A gear 113 is integrally fixed to a sprocket wheel 112 which is driven from a sprocket wheel 85 attached to a sprocket wheel 85 via a chain 86, and the gear 113 is fixed to an arm 114 holding a clock pulse generating magnet 163. The magnet is engaged with the gear 115, which rotates the magnet, and the magnetic detection element 164 fixed to the rear frame 50 and the magnet generate clock pulses at regular intervals synchronized with the rotational speed of the main motor _M1 . Next, we will discuss the operation when paper feeding is defective. The copying machine of this embodiment has a jam detection means for checking whether the transfer paper has completed a predetermined process (feeding, transfer, separation, fixing) and has been ejected from the machine within a predetermined time. If the transfer paper stops due to an accident during the above process and is not ejected outside the machine after a predetermined period of time, the machine is stopped to prevent accidents such as fire. The method of detecting the arrival of transfer paper is to push up a JAM detection roller 180 installed coaxially with the paper ejection roller when the transfer paper passes through the fixing heater 124 and reaches the paper ejection roller 46. Then, the lever 181 is pushed upward to the left, and the magnet 130 attached to the tip of the lever 181 is also pushed up, moving away from the fixed magnetic sensing element 129 and outputting a signal. When a jam is detected, the fuser heater turns off.
Since the main motor M stops, the drum 95 stops, but the document table 2 remains in a predetermined position (home position).
It will stop after returning to that point. When stopped, the upper cover 127, which can be opened around the hinge 131 in FIG. 1, opens vertically together with the duct 128. In this state, there is nothing left on the hot plate 124, and if a jam occurs in the fixing section, the upper cover 124
If you open 7, you can easily remove the transfer paper by hand. Next, the shaft 13 together with the separation part including the hot plate 124
2, and is normally held in place by a locking mechanism 133. By removing the locking mechanism after opening the top cover 127, the shaft 132 can be rotated.
The transfer paper path after the register rollers 41 and 42 is opened, and the jammed transfer paper can be easily removed by hand. At this time, the separation belt 32 separates from the photosensitive drum 15, so that it is easy to take out the transfer paper jammed in the separation section. After removing the jammed transfer paper, the jam release operation is performed and the upper cover 127 is closed, thereby restoring the entire machine to its original state. Next, a method of attaching the cassette 6 to the main body 1 will be described. Cassette stand 144 fixed to the aircraft body
When the fixed part 145 of the cassette 6 is placed on top and the cassette is pushed into the machine, the spring 149 with the roller 148 moves the cassette 6 so that the protruding part 146 at the bottom of the cassette comes into contact with the positioning plate 147 of the cassette stand.
is pressed into place. At this time, the cam 150 and the cassette stand 144 provided on the cassette side wall
Micro switch 151, MS1, installed in
152, MS2 outputs a cassette loading signal and a size signal. Next, FIG. 6 shows the overall circuit configuration for controlling the operation of each device in this copying machine. computer I ₁ ,
Signals are input as input signal groups to I ₂ , I ₄ , and I ₈ from the aforementioned magnetic sensing elements, microswitches, and the like. Signals for driving pulse transformers, small lamps, solenoids, electromagnetic clutches, etc. are outputted from _O1 to _O15 as an output group. At the center is a microcomputer that processes signals from the input signal group, and because the microcomputer performs time-series processing, it must read one input signal from many input signal groups. Therefore, a part of the output of the microcomputer (hereinafter referred to as probe signal) is passed through the input signal group, and used as a probe signal to determine which input signal to read. The microcomputer reads one signal from I1 to I8. The microcomputer processes the read information and performs the processing in Figures 11 and 12, which will be described later.
The signals are sequentially output to the output terminals θ1 to θ15 according to the flowchart shown in the figure. This output signal is input to the output control circuit (FIG. 16), subjected to logic processing, and then output as an output signal group to drive each load. The microcomputer will be explained with reference to FIG. FIG. 7 is an internal circuit block diagram of the TEXAS microcomputer TMS-1000.
Among them, the ROM is a read-only memory in which the contents of the sequence shown in FIGS. 11 and 12, which will be described later, of the copying device are pre-ordered in code and are stored in each address, and the contents can be retrieved each time the address is set. The control contents are stored in 8-bit binary code in order from address 0 to the final required address. RAM is a read/write memory that temporarily stores data, etc. during program execution, and is a memory that stores a set of binary codes. More specifically, as shown in FIG. 8, each bit is constituted by a flip-flop, a set is selected by an address designation signal, and data is written to or read from a plurality of flip-flops within the set. The address in RAM at which information is stored is specified by the X register and Y register. The CPU also has an ALU that has addition/subtraction logical operation functions that decode input data and process the data.
Program counter PC for specifying the address of instructions stored in ROM, Page address register PA for specifying page addresses of instructions stored in ROM, Page buffer PB for changing pages in ROM, Calling subroutines ,
Subroutine return register SR for storing the original return address after subroutine execution is completed,
It consists of an accumulator AR, which temporarily stores the ID operation results for decoding the instructions stored in the ROM. Input terminals I ₁ , I ₂ , I ₄ , I ₈ are connected to K, INPUT, and output terminals O ₁ to O ₁₅ are connected to O,
Connected to ROUTPUT. To give an overview, the CPU first specifies the address of the ROM where the sequence is programmed, the contents of the specified address are read into the CPU through the data line, the CPU decodes this, and according to the decoded contents, the program starts from power-on. In chronological order, sometimes
Processing data within the CPU itself, sometimes storing data in the CPU to a specified address in RAM, inputting data at a specified address in RAM to the CPU, sometimes performs sequence control by outputting data in the CPU to the output signal line of the output section or inputting it into the CPU from the input signal line of the input section. The basic timing for TMS1000 program processing is shown in FIG. The several μsec clock φ (from osc in FIG. 8) shown in FIG. 9 is the basis of program processing. In other words, it takes two clocks to decode the program counter.
It takes two clocks to specify the decoded ROM address, and at the same time the program counter PC is
1, it takes one clock to decode one program instruction in the ROM, and one clock to write it to the RAM, so one instruction is completed in a total of six clocks. The programmed instructions following the above address are executed at similar time intervals. (Input Port) The number of status signals input from the copying machine is large, and since the number of bits of the input port of the computer is 4 bits, the number of bits cannot be equal to 4 bits, so the matrix circuit shown in FIG. 15 is provided as a converter. Table 1 shows the relationship between probe terminals θ1-3 and input ports _I1 - _I8 .

[Table] CLKP is the clock pulse (generated in synchronization with the photoconductor), PEP is the paper out signal, LEP is the liquid out signal, CSTP is the copy button, CBHP is the platen home position, TSC is the toner supply command, PDP is the Paper detection signal (transfer paper), B5, A4, and B4BP are document table reversal signals for each paper size, MS1 and MS2 are micro switches (for paper size detection), and JAMK is a JAM undetectable signal. The input port _I1 is used to input the drum clock CLKP and the idle time signal LDEN (described later). In Table 1, the status from the input signal group changes moment by moment, but the computer reads θ1,
Output a probe signal to either θ2 or θ3,
(These θ1, θ2, and θ3 signals are never output at the same time) Read the desired state signal in 4 bits (I ₁ , I ₂ , I ₄ , I ₈ in parallel) and determine which bit's content is 1 or 0. do. By repeating this operation in chronological order, it becomes possible to judge the input state signal that changes from moment to moment. FIG. 15 shows an input matrix circuit. 30
0 to 308, 310, 311, 313, and 314 are NAND gates, 309 is an inverter, and 312 is an OR gate. The terminal numbers of the circuit correspond to the numbers in FIG. This will be explained using an example of data reading when there is no paper in the cassette and lighting of the paper out indicator lamp. This paper-out signal is obtained from a combination of a lamp and a light-receiving element installed near the cassette attachment of the main body. When the paper runs out, the resistance of the light-receiving element decreases and the detection circuit outputs a paper-out signal (PEP=1). Therefore, the input 3' of the NAND gate 300 of the matrix circuit becomes 0 level. On the other hand, a probe signal θ1 from the microcomputer shown in FIG. 6 is input to 4' of the NAND 300. This PEP signal will be read from the input terminal of _I2 with θ1 set. Reading of other input signals follows Table 1. In the control flow, reading paper etc. is shown in Figure 11.
It is executed in SUBLP of STEP 8, and this STEP 8
As the program progresses, θ1 is set to 1 level each time SUBLP is passed, and θ1 is immediately reset to 0 level when reading is completed. The time from when θ1 is set to when reading is completed is approximately 60 μsec. While this θ1 is set, the other reading probe signals θ2 and θ3 are at 0 level. That is, since θ1 is now set, Fig. 15
Input 4' of NAND300 becomes 0 level, 30
The output of 0 becomes 1. The output of NAND308 is 0
level. This is because the other inputs of 308, ie, the outputs of 303 and 307, are at the 1 level because θ2 and θ3 are not set. The output 24' line of this 308 is input to the microcomputer shown in FIG. 6 and read by the SUBLP program. The read data is stored at address 0 BIT1 (hereinafter referred to as (0, 1)) of the Y register in the RAM area shown in FIG. SUB LP
It is determined whether BIT1 is 0 or 1, and when it is 0, a paper out signal is output as 1 level to θ13 in FIG. 1st
6 When level 1 is output to Figure 34', the buffer inverter 427 turns on, and the output 4 of 427
0 is the 0 level, and the paper out indicator lamp lights up. If there is paper in the cassette, see Figure 15 30.
Since input 3' of 0 is at level 1, 30
The output of 0 is 0 level because θ1 is read at 1 level, and the output of 308 is 1 level, as shown in Figure 8.
BIT1 of RAM is level 1. When BIT1 is at 1 level, it is determined that there is paper, so no paper out signal is output to θ13. In each program step, the data of other input groups is read and judged in the same way, but
Figure 15 Input group signals of matrix circuit and logic gate 310 are OR of PEP, CBHP, BP signals, 3
11 is the OR of LEP, TSC, MS1 signals, 313 is
OR of CSTP, PDP, MS2, JAMK signals
This is what supplies the CPU. The feature of this matrix circuit embodiment is that the original table reversal signals for each paper size, ie, B5, A4, and B4, are input to the OR circuit, and only one reversal position signal is provided on the matrix. Originally, the input signals to be controlled should be 11, but
In this case, the number of probe signals must be increased by one, and there is a limit to the load to be controlled, so only three probe signals can be used. However, at the same time, we focused on the fact that the document platen reversal signals for different paper sizes are not input, so we developed a method (described later) that stores the paper size in the RAM area in the size subroutine and thereby distinguishes the document platen reversal position signal. We are hiring. This has the effect of requiring only three probe signals. Next, the output circuit will be explained with reference to FIG. The terminal numbers of the circuit correspond to those in FIG. In FIG. 16, a circuit composed of an inverter 402, an inverter 405, a resistor 401, a resistor 406, a capacitor 403, and a capacitor 404 is a 5KHz oscillator. This oscillator uses a triax (not shown) to drive an AC load such as a main motor, and a pulse transformer for the triax trigger. , an oscillator for driving the triac. Therefore, AND gates 409, 410, 41
1, 412, and 413 are all pulse transformer loads. The output 52 is the 4-second timer output from the time the power is turned on. 26' is a main motor signal.
This signal is at 0 level for 4 seconds after power-on, and 4
It will be level 1 in seconds. The output of the inverter 407 remains at 1 level for 4 seconds. On the other hand, the other input 31' of the AND 408 is a developing unit motor signal, which outputs a level 1 from the time the power is turned on until the start of post-processing.
Therefore, these AND signals output 1 level for 4 seconds from the time the power is turned on. After that, it will never reach level 0. 37, the document table moves forward and a paper feeding signal is inputted before it reaches the reversal position of B5. When a paper feed signal is input, 37 becomes 0 level. On the other hand, the level 27 becomes 1 level when the document table moves forward. Therefore AND41
5 outputs a paper feed signal only when the document table moves forward, and when the document table moves backward, the signal is input at the same position as when moving forward, but since 27 is at the 0 level at that time.
1 level is not output to AND415. Inverters 416 to 429 are Darlington transistors for driving loads,
Drives the load at input 1 level. Next, the contents of the loads on the inverters 416 to 429 will be shown. Table 2 Inverter 416 is connected to the full exposure lamp (AEXP), 417 is connected to the front exposure lamp (PEXP), 418 is connected to the AC static eliminator (HVAC) main motor (DRMD), 419 is connected to the document platen advance motor (CBFW), 420 is the reverse motor (CBRV), 421 is the + primary charger, - charger, + transfer charger (HVDC), original exposure lamp (IEXP), 422 is the blank exposure lamp (BEXP), and 423 is the developer motor. (DVLD), 424 is power hold relay (PHCD), 425 is paper feed clutch, paper feed counter (PESD/CNTD), 426 is toner out indicator lamp (TEL), 427 is paper (PEL), 428 is connected to the liquid (LEL), and 429 is connected to the JAM indicator lamp (JAML). The paper feed clutch is used to lower the paper feed roller 40, which is constantly rotating, onto the paper after the main switch is turned on, and the power hold relay is used to turn on the switch PHLD shown in FIG. 23-2. As shown in the time charts of FIGS. 13 and 14, the blank exposure is performed by lighting the exposure lamp (IEXP) in substantially the opposite direction to eliminate the difference in the surface potential of the photoreceptor. The paper feed counter counts the number of copies that have been completed, and is incremented by 1 every time the CNTD signal is sent, and is compared with the set number of sheets, and when the number is equal, outputs a copy end signal (turns off the copy button). 13 and 14 show time charts of input signals and output loads. Since it is clear from the figure, the explanation will be omitted. FIG. 10 shows a system flowchart of sequence control, and FIGS. 11 and 12 show more detailed flowcharts. FIG. 10 clearly shows the outline of power-on, process execution, and standby. The terms "front rotation" and "back rotation" correspond to pre-treatment and post-treatment of the photosensitive drum surface. By pre-treatment, the drum surface,
It wipes away toner adhering to the blade and contributes to the formation of a good latent image. Also, post-treatment can remove residual toner on the drum surface before it dries.
Also, by keeping the charger in operation during pre-treatment and post-treatment, it is possible to reduce uneven potential on the drum surface. In this example, the blade remains in contact with the drum from beginning to end, but by making contact and non-contact depending on whether the power is turned on or off, the blade marks on the drum surface can be reduced. (Reset) Following the power-on, the power-up preset signal (PU-RS) is activated for approximately 4 seconds after the power is turned on, as a timing to judge how long the copying machine has been left unused before the power is turned on, and as a time to issue a command to reset the entire circuit. )make. These four seconds are created by a program. That is, as mentioned above, the number of clocks required to execute one instruction among the instruction group stored in the ROM is six clocks. This clock frequency is set to 300KHz by the OSC shown in FIG. That is, the time of one clock is T=1/
f [seconds], it becomes about 3.3 [μsec], and with 6 clocks it becomes about 20 [μsec]. Therefore, it takes 20 [μsec] to execute one instruction.
Create a 4 second timer with 200000 instructions. In other words, following power-on, RAM area Y address 1 is
15, put 15 in 2, 15 in 3, 10 in 4, first
Subtract the number 15 in RAM area 1 to 0
Repeat until. If it becomes 0, RAM area 2
Subtract 1 from the 15 contained in to make it 14. next,
Enter 15 again into RAM area 1, which is set to 0.
Then, the subtraction of RAM area 1 is repeated until it becomes 0. 1 from the contents of RAM area 2 every time it becomes 0
, and each time the area of RAM2 becomes 0,
Subtract 1 from area 3 and then use RAM areas 1, 2,
Repeat until 3 and 4 are all 0. The numerical value of the RAM area is determined so that the number of instructions during this period is approximately 200,000. Note that, in addition to this embodiment, a method for realizing this 4-second timer is shown in FIG. The method shown in FIG. 20a is an oscillator that oscillates a signal at intervals of, for example, one second. A certain output signal of the microcomputer is used to read the oscillator signal into the microcomputer. For example, if the oscillator is used for one second, the microcomputer only needs to count four times, and the number of program steps can be extremely reduced. Further, the method shown in FIG. 20b is a method of counting clocks generated in synchronization with the photoreceptor and when the frequency is relatively low. The method shown in FIG. 20c is a method in which the microprocessor driving clock frequency is reduced to a low frequency using a frequency divider and this frequency is counted.
This method is effective when creating a highly accurate timer. Also, since this copier will not be used for a long time, toner tends to stick to the cleaning blade if it is left unused, so if it is left unused for more than 7 hours, pre-processing should be performed more often (approximately 40 seconds) than usual. It's becoming like that. Figure 21-1 shows the external circuit configuration for that purpose.
Figure -2 shows the time chart. The circuit configuration is CR
It consists of a timer circuit, reset circuit, delay circuit, comparison circuit, and driver circuit. To explain the operation, when this copier is in operation, the main switch (SW) is on, so the CR timer capacitor is charged via DC 24V.
If the charging time is 30 seconds or more, the capacitor will charge up, and this capacitor has extremely low leakage current. When the main switch is turned off, the capacitor starts discharging.
If the standing time exceeds 7 hours (time for the toner to stick to the cleaning blade), the potential of the capacitor will drop and the next time the main switch is turned on, the comparator (CMP) will be activated by a potential input below a predetermined level, and the delay circuit will cause the time ( The output transistor is turned on for approximately 10 seconds) and the long-time leaving signal LDEN signal is output. When the delay time ends, the reset circuit activates and starts charging the capacitor again. On the other hand, if the left time is less than 7 hours, the capacitor potential is above the specified level, so the comparator does not operate, and the output transistor is OFF and the capacitor is charged again. Start charging. The setting time is determined by the capacitance of the capacitor. After turning on the power, first execute STEP 1 using the method described above,
The developer motor turns on. (STEP 2) This developer motor can also pour developer into the vicinity of the contact between the blade and the drum surface, thereby dissolving the dried toner on the blade and drum and facilitating cleaning during pre-treatment. Next, in STEP 3, the JAM detection circuit is disabled (hereinafter referred to as JAM
(referred to as murder). JAM killing is often performed when performing maintenance services on this copying machine to check the sequence operation without sending any paper. In computer control, unless the JAM detection circuit is disabled in this case, the JAM indicator lamp will operate and the sequence will stop, making it impossible to confirm the sequence. Therefore, in this embodiment, if CP1 is short-circuited to ground before power is turned on in FIG. 8, the output of the inverter 210 becomes high level (hereinafter written as 1), and the matrix circuit (FIG. 15) Enter 21'. On the other hand, 1 level is inputted from the output terminal 52 to the matrix circuit 1' for 4 seconds after the power is turned on. accordingly
The output of NAND314 is at 0 level for 4 seconds.
During this time, the output of AND310 is at 1 level. This is because the 4-second timer is created only by a microcomputer program, so θ1, θ2, θ3
This is because no probe signal is being output from the Then, the output of NAND312 becomes 0 level. STEP 3 reads this 0 level. As will be described later, the information read in STEP 3 is stored in the RAM and used when determining whether the transfer paper has arrived in STEP 38 of FIG. 12. Next, the process proceeds to STEP 4, and it is determined whether the aforementioned 4-second timer has timed up. When the time has expired, the process proceeds to STEP 5, and the load of the main motor etc. is turned on. In STEP 6, the LDEN signal is output for about 90 seconds after the power is turned on by the above-mentioned leaving time measuring circuit shown in Fig. 21, so the
After seconds, the computer reads the LDEN signal from the RAM.
A flag is set on one stroke of .At this time, the photoreceptor is not rotating yet, so CLKP is not input. Furthermore, after the 4 second timer ends, AND201
Since the PURS signal is at 0 level, even if the 1 level of the LDEN signal is input, the output of AND201 is at 0 level, so the output of OR gate 202 is that only the clock pulse CLKP signal generated in synchronization with the photosensitive drum is input to the computer. be done. After the 4-second timer ends, the content of the data read in STEP 6 is determined in STEP 7, and if the standing time is 7 hours or more, the drum is further rotated in STEPs 8 and 9 and pretreatment is performed for 40 seconds. During this time, it is ON in STEP 5.
Only the old load is being driven. If the leaving time is less than 7 hours, the preprocessing 40 second timer does not operate and the process moves to STEP10. Here, while the 40 second timer is not up, subroutines SUB CBRV, SUB LP, and SUB SIZE are executed. This SUB CBRV, SUB LP, SUB SIZE is 40
While the second timer is operating, a routine is used to constantly detect when the document table comes into contact with the document table and moves out of its normal position, if paper is not inserted into the paper cassette, or if a cassette with a different paper size is replaced midway through. It is. These steps will also be used in subsequent steps.
There are SUBROUTENs everywhere. The 40 second timer is based on counting 80 clock pulses (CLKP) (one clock time is approximately 0.5 seconds) generated in synchronization with the photoreceptor mentioned above. When the 40 seconds process is completed, STEP 10, 1
Count 10 CLKPs at step 1. As mentioned above, this copying machine performs one revolution of preprocessing regardless of whether preprocessing is performed for 40 seconds. If pre-processing is performed for 40 seconds, perform one rotation of pre-processing after this, and if pre-processing is not performed for 40 seconds,
After completing PURS, preprocessing is performed once. In STEP 11
Determine whether CLKP has been counted to 10. This is to prevent the copy operation from starting until at least 10 clocks have been counted, in case the copy button is pressed during preprocessing. FIG. 17 shows details of STEP 10 and STEP 11. In Figure 17, 10 in STEP10-1
Clock counting is started, clock reading is started in STEP 10-2, and it is determined whether the clock signal CLKP is at 1 level or 0 level. If CLKP is now at level 1, the process proceeds to STEP 10-4, where it is determined whether the document table is at the home position before scanning. If it is not in the correct position, the document platen back motor
Outputs the ON signal (θ6 output in Figure 8). Furthermore, it determines the paper size, monitors the loading of the cassette, and determines the presence or absence of liquid and displays a warning. If CLKP reaches 0 level, STEP10-7, STEP10-
Proceed to step 8 and repeat the same process. If CLKP reaches level 1 again, it means that 1 clock has been counted, so repeat this and reach 10 in STEP 10-12.
Determine whether the clock has been counted. While counting 10 clocks, the clock is 1
Whether it is level or 0 level, other controls are always possible continuously. This control method has since become the basic control method when performing other controls while reading CLKP. This method is particularly effective when it is necessary to perform other tasks while counting clocks, such as when detecting the protrusion of a document table from its home position. In other words, even if the document glass is reversed by the reverse position signal, the home position is detected, and the document glass back motor is turned off, the document glass still protrudes from the home position (because the user of this machine touched the document glass). )Sometimes. However, in order to correct this jump, the clock's 0 level or 1
If you want to detect the protrusion of the document platen when the level is set,
For example, if you create a program that detects pop-up only when the 0 level is detected, the document table back motor will be turned on when the document table is at the 0 level and an attempt is made to return the document table to the stop position, but in the middle of returning, the clock changes to the 1 level. Even if the original platen back motor remains ON, there is a risk that the back motor will be overloaded. Next, after the CLKP10 count ends, STEP 12 is executed to check whether the copy button is pressed. If the copy button is not pressed, the remaining 6 clocks of one rotation of preprocessing will be counted.
Execute STEP13 and STEP14. If the copy button has been pressed, proceed to STEP 21 and execute the copy process. After completing one rotation of pretreatment, proceed to STEP 15.
The main motor, high voltage AC, turned on in STEP 15,
Turn off all but blank exposure. The process then proceeds to the post-processing step described above. During this post-processing, the potential on the photoreceptor is made uniform. During this post-processing, a power hold signal is generated to maintain power supply to the control circuit even if the main switch is turned off. Even during post-processing, STEP 16 is executed to detect whether the copy button is pressed and to make two revolutions of the drum for post-processing, that is, to count 32 clocks. If the copy button is on, the process advances to step 21. When the post-processing is completed, the copying machine goes into standby mode. This is why all loads are turned off in STEP 19. During standby, it must always detect whether the copy button is pressed.
This is executed in STEP 20. Copying machines are often left in this standby mode for long periods of time, but since the temperature inside the machine is higher than the room temperature, toner adhering to the cleaning blade tends to stick. Therefore, there is a possibility that the next image formation will be adversely affected. Therefore, during standby, the clock is counted using the means shown in FIG. 20, and after several minutes have elapsed, the main switch is turned off. Next, when you press the copy button, STEP 12, 16,
Determine it in 20 and proceed to STEP 21. STEP 2
The load shown in 1 is turned on and the drum rotates. Then, 9 clocks are counted in order to avoid the drum area that adversely affects the image. STEP 22 is a step for determining whether the copy command is interrupted by pressing the stop button. If the process is not interrupted, in step 24, after 9 clocks have been counted, the CBFW signal is output from the output terminal θ5 to move the document table forward. The minimum paper size is B5, so the document table first reaches the B5 inversion position. Then, the signal B5BP is output. Incidentally, the paper feed signal PESP is obtained from a Hall element provided at a position before the reversal position of B5 as the document table moves.
When B5BP is confirmed in STEP 26, the SUBTSL routine is executed in STEP 27 to detect the developer concentration. If the developer concentration is low at this point,
Set the no toner flag in RAM and use it for sequence processing described later. Next, in the paper size determination routine of STEP 28, it is determined which paper size cassette is currently installed. As mentioned above, this is the micro switch MS
1. A paper size signal is created by combining MS2. There are four possible combinations, but this copying machine uses three sizes, so the remaining one is used as a signal when no cassette is installed. When the paper size is determined in STEP 28, the size flag is set in the RAM and the process branches to one of the flows related to B5, A4, and B4 sizes (FIG. 12). It is recommended that the drum surface be cleaned by rotating the drum for 9 clocks or more after pressing the copy button. Details regarding B4 size are given below. In STEP 84 of FIG. 12, the process waits for B5 to pass through the reversal position. A magnet provided on the document table for detecting the inverted position of the document table has a certain width.
Therefore, it takes a certain amount of time (several hundred milliseconds) for the document table to pass over the Hall element. During this time, the microcomputer executes the previous paper size determination routine. Then, it waits for a sheet of paper size other than the desired size to pass through the reversal position. That is, for A4 size, the fall and rise of the signal of the B5 back position detection Hall element are detected, and for A4 size
For the larger B4 size, its passage is determined by detecting the falling and rising edges of the signal of the Hall element for B5 and A4 reversal position detection (STEP 84, 8)
5,86). Then, in STEP 87, when it is determined that the document glass has reached the reverse position of B4, in STEP 88, the document glass advance signal CBFW and the blanking lamp are output.
Turn off BEXP and output reverse signal CBRV. Next, STEP 89 is the retention jam detection routine PDP
In step 1, when the document table reaches the reverse position of B4, it is determined whether the paper detector 180 (Fig. 1) detects paper or not. When this occurs, the progress of the process STEP is stopped, a stagnation alarm is issued, and the next paper feed is stopped. This is effective during continuous copying. If the paper is not retained, it is determined in STEP 90 whether the document table has returned to the home position, and when it has returned, the document table stops moving backward (STEP 91), and the process proceeds to a paper delay jam determination routine PDP2 (STEP 92). Note that the subroutine TSSD is executed between determining B4BP and the original platen stop position. This routine resets the flag set in the RAM in the TSL routine of STEP 27 when the developer concentration is restored in executing STEPs 87 and 90. Also, the JAM detection PDP2 routine in STEP 92 is a delayed JAM detection, and since it has been determined in STEP 89 that the previous sheet is not stuck, this time the transfer paper that is currently being transferred and is about to be ejected is jammed inside the machine. Detects cases where the paper is not delivered due to an error or an error in feeding the paper. That is, if the transfer paper has not reached the JAM detector at the time of STEP 92, a delay alarm is issued and the next paper feed is stopped or the machine is stopped. STEP92
If it is determined that there is no JAM, STEP 93
Proceed to , and check the copy button to determine whether you want to copy one copy or multiple copies. Assuming that one copy is to be made, STEP 94 and STEP 95 are executed to count 7 clocks. This is a program that prepares the timing for entering the post-processing step. Relatively short sheets such as B5 size paper are ejected earlier than B4 sheets, so they enter post-processing in less than 7 clocks. Note that even if the paper size is different, post-processing always begins when the trailing edge of the paper finishes passing through the paper ejection roller. Also, the timing can be changed so that the post-processing starts regardless of the paper size, for example, the timing can be changed so that the post-processing starts at which clock from the back position of the document table B5. In STEP 96, it is determined that there is no toner to be supplied. This is a routine TEL. This judgment is made in STEP 27.
If the flag that was set when the developer concentration is low in the back position of B5 cannot be reset because the developer concentration is still low in the SUB TSSD such as STEP 87 or STEP 90, the concentration is determined again and developed immediately before starting post-processing. If the liquid is too thin, it will issue an alarm that there is no toner. Since it takes a long time from the back position of B5 to the start of post-processing, even if the developer concentration is low, if there is replenishment toner, the concentration will return to the specified level immediately after replenishment. The input signal TSC at this time becomes a signal that the toner is thin for a long time, that is, a signal that there is no toner to be replenished. This is explained in detail in Figure 19-1.
The ATR circuit and the flowchart of FIG. 19-2. Figure 19-2 shows the B5 size.
In FIG. 19-1, 501 is a developer concentration determining circuit, and if the concentration of the developer is low, the output of 501 becomes 1 level. On the other hand, the toner supply area is
This is the period from when the document table moves forward to when post-processing begins.
If there is no toner supply area, for example, if the main switch is repeatedly turned on and off, a low toner signal may be output each time. This is because the liquid concentration is determined by irradiating the liquid passing through the slit with a lamp, receiving it with a light receiving element, and detecting the change in the resistance value of the light receiving element. In this case, when the main switch is turned on, the developer motor starts rotating and the lamp lights up before the liquid flows into the slit. This is equivalent to the fact that the resistance of the light receiving element is small and the concentration of the liquid is low. I will supply it. So, turn on the main switch,
If you turn it off repeatedly, the developer concentration will become abnormally high.
This will have a negative effect on the image. Even if the current concentration of the liquid is low and the output of 501 is 1, the signal TSC will be transmitted to the transistor 50.
Since 6 is ON, it is shorted to ground. This is because θ7 is at the 0 level compared to the signal from the microcomputer, so the inverter 5
The output of 08 becomes 1, and the transistor 506 becomes
This is because it is turned on. On the other hand, when the document table moves forward in STEP 25-1, a toner replenishment enable signal is output in the next STEP. Therefore, the output of the inverter 508 becomes 0 level for the first time at this time, and the transistor 506 becomes
It is turned OFF, the output level 1 of the operational amplifier 501 is supplied to the transistor 502, and the toner supply solenoid 503 is activated. However, when there is no toner, the output of the operational amplifier 501 is 1, and the output of the inverter 505 is 0, and a signal indicating that the toner is thin is read into the microcomputer through the matrix circuit. That is,
In the TSL routine of STEP 27, the toner out flag is memorized in the RAM area and in STEP 30 and 41.
The TSSD routine does not reset that flag.
After the JAM judgment ends, when post-processing starts, immediately before that
STEP 50 TEL routine (in B4 size
The RAM that was set earlier in STEP 96)
Determine the setting of the flag within the area to indicate that there is no toner. After completing JAM detection and toner out determination
Moving from STEP 50 or 96 to the step shown in FIG. 11, post-processing is started and the above-described operations are repeated. That is, the present invention includes a photoreceptor for forming a latent image;
A plurality of process means for image formation, including a developing means for developing the latent image formed on the photoreceptor with a developer, a source for generating a timing signal for operating the process means, and a concentration of the developer. or a detection means for detecting the amount (ATR 501), a replenishment means for replenishing the developer (toner supply solenoid 503), and various control signals for operating the process means based on a timing signal from the timing signal generation source. a first control means (microcomputer) that outputs a second control means (transistor 502) that controls replenishment of the developer based on a detection signal from the detection means;
The first control means outputs a developer replenishment enable signal to enable replenishment control by the second control means (STEP 25-2 in FIG. 19-2), and
The control means performs developer replenishment control to bring the developer into a desired state based on the developer replenishment enable signal when the detection signal from the detection means is a signal indicating an inappropriate state. This is an image processing device characterized by: According to the present invention, the first control means for controlling a plurality of process means including the developing means outputs a signal for enabling the second control means for controlling developer replenishment. It becomes possible to perform replenishment control while avoiding periods when the detection of the concentration or amount of developer is unstable, and it is possible to prevent malfunctions in developer replenishment control. We have just explained one-sheet copying, but in the case of multiple-sheet copying, the document table reaches the home position and the STEP
If it is determined in step 93 that the copy button is pressed, the process moves to FIG. 11 and the document platen advance signal is sent again.
Turn it on and repeat the same process. So far, B4
Although we have explained the size sequence, it is the same for other B5 and A4 sizes, and the only difference is the JAM detection method, so we will omit the explanation. The JAM detection method will be explained in detail with reference to FIG. In B5 size (Figure 18-1), first
After the document table reaches the home position in STEP 30, the routine of FIG. ), in STEP 48, another 4 clocks are counted and it is determined whether the transfer paper has reached the paper detector 180. Note that when the signal has been reached, the signal from the Hall element 129 is at 0 level as shown in FIG. 23C. (Transfer paper delay) If the paper arrives at the paper detector 180, it indicates that the transfer paper is being fed normally. On the other hand, the B4 size is as shown in Figure 18-2 (described above). This operation is shown in a time chart as shown in Fig. 18-3. Therefore B5
For size, use clock, and for B4 size, use B4
The reverse position signal and stop position signal are used.
In this way, since jam detection is performed by selectively using the clock and the signal on the document table depending on the paper size, it is possible to perform convenient discrimination control even when the jam discrimination and load operation are similar. Furthermore, as shown in FIG. 18-3, when B5 is used to continuously copy a large number of sheets, the delay is determined by B5BP, and only the last copy is clocked. In addition, in this embodiment, a clock is used to detect JAM for B5 and A4 sizes, but the above-mentioned
A frequency-divided version of the microcomputer's drive clock φ or an external low-frequency oscillator can be used. In this embodiment, CP1 (JAMK) in Figure 8 is shorted to ground to disable these JAM detection operations, but it is also possible to electrically input the number of copies etc. from the outside. This can be done using the numeric keypad. In other words, JAM killing, liquid killing (ignoring signal LEP discrimination), paper killing, JAM killing,
Liquid killing, paper killing (ignoring signal PEP discrimination)
Encode the input signal for
A flag is set at a specific address within the area, and a step is provided in advance to jump this step immediately before the jam discrimination, liquid, and paper discrimination step during the program, and when the program is executed at this step, the RAM is The corresponding killing data storage address is read and it is determined whether the flag is 1 or 0. When it is 0, the program proceeds to each determination step, and when it is 1, the program jumps the determination step and proceeds to the next sequence step. Furthermore, in the present invention, even if the magnetic detection element for B5, A4, etc. is damaged, the document table is automatically returned to the longest paper size. If the magnetic detection element that detects the document platen reversal signal for the longest paper size is damaged, the document platen advance motor may be overloaded because there is no reversal input. When the document table moves forward, the time from when the document table moves forward to the reverse position of the document table for the longest paper size is fixed for any paper size, so a timer for this fixed time is created by counting CLKP. Therefore, since the paper size flag is stored in memory as mentioned above, a predetermined inversion signal (predetermined
If ) does not appear when counting CLKP, the document platen will be automatically reversed. This timer is the CLKP mentioned above.
count, use an external low frequency generator,
A frequency obtained by dividing the microcomputer drive clock φ is used. Table 2 shows an example of the flow shown in FIGS. 11 and 12 in program code, and since the command words are clear in the user's manual of TMS1000, they are omitted. Next, the power supply circuit shown in FIG. 22 which supplies the microprocessor computer will be explained. This circuit is
It consists of a 15V stabilized power supply circuit and a 15V shutoff circuit. In this copying machine, even if the main switch is turned off during the post-processing after the copying operation is finished, the post-processing is executed to the end and then the drum rotation and load energization are stopped. If so, a control step is provided to issue a power hold signal. This copying machine includes a power transformer for supplying DC to the control circuit and other DC loads. A 24V rectifier circuit is used on the secondary side of this power transformer, but a very large capacitor (for example, 2200 μF) is inserted in the smoothing circuit of this rectifier circuit. On the other hand, on the primary side, this power transformer is ON,
A line where AC100V is supplied by the main switch for OFF, and the main switch is OFF during post-processing.
There are lines that supply 100V AC even if the The signal that drives this circuit is the aforementioned power hold PHLD signal so that AC100V is supplied even if the main switch is turned off during post-processing. The cleaning blade can be removed from the drum by turning off the PHLD, and then brought into contact with the drum by turning on the power. Now, if the main switch is turned off during post-processing, a power hold signal is output, and the power hold signal is turned off after post-processing, the primary side of the power transformer will be turned off, and the rectifier circuit on the secondary side of the power transformer will also be turned off. However, because the smoothing capacitor in the smoothing circuit has a large capacity, the discharge time is long (about several hundred milliseconds). Moreover, there is ample margin in the operating range of the power supply voltage of the microcomputer. Therefore, if the power supply voltage waveform drops in a gentle curve around the voltage at which the microcomputer begins to malfunction, the microcomputer's RAM, ROM, etc. will begin to malfunction. At this time
If a power hold signal is issued due to an incorrect output from RAM or ROM, the AC100V line mentioned above will become active again even though the main switch has been turned off and rotation has ended. In this case, of course, other microcomputer
There are also invalid values in the RAM area, which causes display lamps such as the JAM indicator lamp to light up, adversely affecting operation. FIG. 22 shows a shutoff circuit that eliminates this drawback. In the figure, 601 is a resistor for flowing the Chener current, 602 is a 20V Chener diode, and 605
is an NPN transistor, 604 is a transistor collector resistor, 607 is an NPN transistor, 60
6 is a transistor collector resistor, 608 is a voltage drop resistor, 611 is a 16V Chener diode, 6
10 is a silicon diode 609 is a control transistor. To explain the operation, the circuit composed of the resistor 608, the transistor 609, and the Zener diode 611 is a known constant voltage circuit, so the explanation will be omitted. The chainer voltage of the chainer diode 602 is about 20V, and the base current is supplied to the transistor 605 through the resistor 601. Now +24V
is input to this circuit (the input is connected to a circuit that smoothes the transformer output, and the 15V output is connected to the computer power supply terminal), that is, while post-processing is being performed,
A chener current flows through the chener diode 602, the transistor 605 becomes conductive, and the resistor 60
A current flows through transistor 4, and the collector of the transistor is at almost zero potential. On the other hand, since no base current is supplied to the base of the transistor 607 through the resistor 604, the transistor 607 is in a non-conductive state. Therefore, only the chener current supplied to 611 flows through the resistor 606, a 16V chener voltage is maintained across both ends of the chener diode 612, and a 15V constant voltage is supplied to the output. However, as mentioned above, the post-processing is completed, a power hold signal is output from the control circuit, and the +24V power supply gradually decreases. +24V
When the voltage is around 20V, the Chener diode 6
02 becomes non-conductive, transistor 605 becomes non-conductive, transistor 607 becomes conductive, the collector of transistor 607 has a potential of approximately 0V, no chiener current flows through 611, and the output voltage becomes 0V. A diode 610 is provided to block a reverse voltage momentarily applied between the base and emitter of the transistor 609 at this time. In this way, when the +24V voltage reaches around +20V, the power supply to the load is forcibly stopped. Therefore, even if the discharge time constant of the smoothing circuit is extremely large, it is effective for a control circuit having a memory circuit.

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【table】 [Brief explanation of the drawing]

FIG. 1 is an external perspective view of an example of a copying machine according to the present invention, FIG. 2 is a vertical cross-sectional view of FIG. 1, FIG. 3 is a cross-sectional view of FIG. 1, and FIG. 4 shows the driving relationship of the copying machine. 5 is a perspective view of the cassette, FIG. 6 is a control circuit diagram, FIG. 7 is a block diagram of the microcomputer, FIG. 8 is a RAM area diagram, and FIG. 9 is a basic time chart of the microcomputer. 1st
Figure 0 is a system flowchart of the operation of the copying machine in Figure 1, Figures 11 and 12 are detailed flowcharts of Figure 10, Figure 13 is an operation timing chart for B5 size, and Figure 14 is the operation for B4 size. Timing chart, Figure 15 is an input matrix circuit diagram, Figure 16 is an output control circuit diagram, Figure 17 is a control flowchart for clock 1 level and 0 level, Figure 18-1 is a B5 size jam detection flowchart, Figure 18-2 is a B4 size jam detection flowchart, Figure 18-3 is a jam detection timing chart, Figure 19-1 is an ATR flowchart, Figure 19-2 is an ATR circuit,
Figure 0 is the clock generation diagram, Figure 21-1 is the measurement circuit when left unused, Figure 21-2 is the operation time chart of Figure 21-1, Figure 22 is the power supply circuit, and Figure 23 is the input of Figure 6. This is an example of a sensor circuit, and I ₁ ,
I ₂ , I ₄ , I ₈ are input terminals to the computer, O ₁ to _{O 15}
are output terminals to the computer, A4BP, B4
BP, B5BP are document platen reversal position signals, MS ₁ , MS ₂
is the cassette size signal, DDP is the paper detection signal,
TSC is a toner concentration signal, and TSE is a toner replenishment enable signal.

Claims (1)

[Scope of Claims] 1. A photoreceptor for forming a latent image, a plurality of process means for image formation including a developing means for developing the latent image formed on the photoreceptor with a developer, and the process means A source that generates a timing signal for operating the timing signal, a detection means that detects the concentration or amount of the developer, a replenishment means that replenishes the developer, and a process means that generates a timing signal based on the timing signal from the timing signal generation source. a first control means for outputting various control signals for operating the above; and a second control means for controlling replenishment of the developer based on a detection signal from the detection means; The second control means outputs a developer replenishment enable signal to enable replenishment control by the second control means, and when the detection signal from the detection means is a signal indicating an inappropriate state, An image processing apparatus that performs developer replenishment control to bring the developer into a desired state based on a developer replenishment enable signal.