JPS647385B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic copying machine provided with means for removing optical memory generated on a photoreceptor for forming an image.

Conventionally, in electrophotographic copying machines, it is necessary to perform various operations such as when copying paper jams, when cleaning areas contaminated with developer, etc., or when replacing or repairing photoreceptors and other consumable parts.
I had to open the front door of the copying machine and reach inside to treat the problem. Alternatively, it has sometimes been necessary to remove the rear or upper exterior, and sometimes even unrelated parts within the main body. Therefore, recently, a copying machine has appeared in which the main body can be separated vertically from one end along the copying machine feeding/conveying path, and it has become possible to considerably alleviate the above-mentioned difficulties.

However, since separation is possible in this manner, the photoreceptor is exposed to external light during separation, resulting in a large change in the characteristics of the portion of the photoreceptor exposed to the light. Therefore, when the separated upper and lower parts of the copying machine main body are closed again and a copy is made, an optical memory effect occurs, causing problems. For example, because not enough charge is placed on the photoreceptor, the first few copies may show white areas corresponding to the photoreceptor parts exposed to external light, or the colors of the formed images may become pale. There will be negative effects.

In particular, when a user encounters a paper jam, separates the top and bottom of such a copying machine, removes the jammed paper, closes it again, and makes a copy, the user is unable to output blank copy paper. I must say that this is extremely inconvenient for them.

In view of the above drawbacks, the present invention makes it possible to separate the copying machine main body substantially along the paper conveyance path, reliably detects this separation operation, and based on this detection,
An object of the present invention is to provide an electrophotographic copying machine equipped with a means for removing optical memory of a photoreceptor caused by exposure to external light.

As mentioned above, the photoreceptor is exposed to external light mainly when the upper and lower parts of the main body are separated and opened due to a paper jam or maintenance. Upon detection of this, the optical memory removing means is energized.

Here, when separating the upper and lower parts of the copying machine main body, the power supply to the main parts inside the copying machine is generally stopped for safety reasons. Therefore, according to the present invention, in order to detect that the copying machine main body is opened, the power supply to the image forming means etc. is cut off.
The power supply to the means for detecting vertical separation according to the present invention is not cut off.

In particular, the power switch is connected in series with a door switch, etc. for opening the main body of the copying machine vertically. Therefore, the door switch is opened in connection with the vertical separation, and in response, a part of the copying machine is opened for safety. The power supply will be cut off.

Therefore, in the present invention, the detection switch for detecting the closing state is connected to the control circuit of the optical memory removing means via a power circuit separate from the power switch and the similar switch. In other words, in connection with the separation operation of the copying machine main body, only the power supply to the image forming means etc. is cut off, and the means for detecting the separation operation is
By continuing the power supply, the optical memory removing means is driven in conjunction with the power supply to the copying machine. As a result, the optical memory removal operation is performed only when the copying machine main body is separated.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a copying machine according to the present invention, and FIG. 2 is an external view showing the main body of the copying machine separated into upper and lower parts. In the figure, reference numeral 1 denotes a drum-shaped photoreceptor that is rotationally driven in the direction of the arrow. On the circumferential surface of the photoreceptor 1, various copying processes for image formation are arranged facing each other. Reference numeral 2 denotes a corona charger for uniformly charging a photoreceptor disposed facing around the rotating circumference of the photoreceptor 1; 3 a corona charger for exposing an image of an original 5 on an original platen 4 to the uniformly charged surface of the photoreceptor; 6 is an illumination device that illuminates the original 5; 7 is a developing device that visualizes the electrostatic latent image formed on the surface of the photoreceptor 1 as a toner image after image exposure; 8 is a system that a corona charger for electrostatically transferring the toner image onto the copy paper 9 sent by the
Reference numeral 10 denotes a corona charger for eliminating charges remaining on the photoreceptor 1, and 11 denotes an optical charge remover using a lamp. In the copying machine shown in FIG. 1, the developing device 7 also serves as a cleaning device to remove toner remaining on the surface of the photoreceptor. or,
12 is a heat fixing roller for fixing the toner image on the copy paper 9, and 13 is a discharge roller for discharging the copy paper 9 after fixing.

In the copying machine shown in FIG. 1, in order to separate the copy paper 9 into upper and lower parts along the conveyance path (the part indicated by the dotted line), the upper part 15 and the lower part 16 It has a structure that allows it to rotate against the other direction. Various copying processes provided around the photoreceptor 1 are attached to the upper part 15 of the copying machine main body, and only a corona charger for transfer is attached to the lower part 16 side. In this case, upper and lower rollers of the conveyance system are provided respectively. Between the upper part 15 and lower part 16 of the copying machine main body,
A spring 17 is attached, and the upper part 15
is always urged upward around the support shaft 14.
Further, the upper part 15 is fixed to the upper part 16 by a locking member 18 provided on the upper part 15 being locked with a locking member (not shown) provided in the lower part 16. That is, when the locking member 18 is released, the upper portion 15 is opened by the biasing force of the spring 17 as shown in FIG. At this time, a part 1a of the photoreceptor 1 attached to the upper part 15 is exposed to external light 19, and optical memory is generated in that part.

In addition, 20 in the figure is a micro switch that detects opening/closing of the upper part 15, and is attached to the lower part 16. 21 is a power switch, and 22 is a door switch. The door switch 22 is opened when the exterior of the copying machine (not shown) is removed, and this exterior is removed when, for example, the upper part 15 is opened. The power switch 21 is connected in series with the door switch 22 to the power supply circuit, and if any of them is opened for safety, it cuts off the power supply to, for example, the image forming means in the main body of the copying machine, and As shown in Figure 5, the power supply for copy control +
V ₀ is also blocked.

Particularly, in the copying machine of the present invention, the heat fixing roller 1 is
2 and copy paper 9 are driven at the same time. Therefore, the heat fixing roller 12 does not require a transmission clutch or the like for rotation control and is directly connected to the main motor. The above-mentioned transport system also has a similar configuration.

Next, a specific example of optical memory removal according to the present invention in the copying machine configured as described above will be described in detail. First, the copying operation of the copying machine of the present invention will be explained. When the copy switch is pressed, the photoreceptor 1 starts rotating. A synchronization disk 23 in which a synchronization slit is formed is provided coaxially with the photoreceptor 1, and upon receiving a signal from this synchronization disk 23,
The copying control circuit performs various copying processes (image forming means) for sequentially and repeatedly forming images on the photoreceptor 1.
drive and control. This copying control circuit is conventionally well known and is used to sequentially control a copying machine. First, the corona charger 2 is driven to sequentially and uniformly charge the photoreceptor 1. Then, when the image formation start tip of the photoreceptor 1 reaches the exposure start position,
The movement of the original platen 4 is started, and at the same time, image exposure is performed on the photoreceptor 1 via the optical system 3. Next, the latent image formed by the image exposure is visualized as a toner image when it reaches the position of the developing device 7, and is transferred onto the copy paper 9 fed through the conveyance system by the action of the transfer corona charger 8. The toner image is transferred. After this transfer, the remaining charge on the photoreceptor 1 is removed by a corona charger 10 for charge removal, and further the charge is optically removed by an optical charge remover 11. Then, when the photoreceptor 1 passes through the corona charger 2, if it reaches the developing device 7 without being corona charged and without being image exposed, the residual toner is removed and it is ready for the next image formation. In other words, one copy is made by the photoreceptor 1 rotating twice.

On the other hand, the copy paper on which the toner image has been transferred is peeled off from the photoreceptor 1, passes through a heat fixing roller 12, is fixed, and is discharged from the copying machine via a paper discharge roller 13. During the copying operation described above, the copy paper 9
If paper is jammed in the conveyance path, the upper part 15 of the copying machine main body is released from the lower part 16 by releasing the locking member 18, and the jammed paper is removed. In this case, since the copying machine main body upper part 15 is separated along the conveyance system, it can be easily removed. After this removal, the upper part of the copier main body 1
5 to the lower part 16. In this case, when the upper part 15 is opened, a part 1a of the photoreceptor 1 is irradiated with external light 19, and a light memory effect acts on this part. In order to remove this optical memory, a detection switch 20 that detects changes from the closed state to the open state and from the open state, which is connected to the upper and lower parts of the copying machine main body, reliably detects the state and outputs the signal signal. , in response to this, the optical memory removing means is driven by power supply.

Next, the optical memory removing device for the photoreceptor 1 will be described in detail.

FIG. 3 is a diagram showing a specific example of the drive circuit of the optical memory removal device. The apparatus of the present invention drives each copying process to remove the optical memory. In other words, the synchronizing disk 23 is used, and each copying process described above is driven by signals from the disk 23. As shown in FIG. 4, the synchronous disk 23 has seven slits Pa ^-0 to ^{Pa -6} formed therein, and the slits are detected by a detector consisting of a light emitting diode 24 and a phototransistor 25. Note that the synchronous disk 23 is shown without the slit for copying. In the synchronization disk 23, the position of the slit Pa ^-0 corresponds to the start position (standby position) of the photoreceptor 1, and determines the image forming start tip of the photoreceptor.

In the circuit diagram of FIG. 3, +V is a constant voltage power supply from the power supply circuit 60 as shown in the circuit diagram of FIG. The power supply circuit 60 is provided to supply power for removing the optical memory without going through the power switch 21 and the door switch 22.

The emitter output of the photo transistor 25 in FIG. The other input terminal of the AND gate 27 is supplied with the output of the MB 26 . When the MB26 receives the slit signal PA from the synchronous disk 23, its output becomes "H" for a certain period of time.
The slit signal PA ^-6 is output by the rotation of step 3.
The time is set to be slightly longer than the period t during which PA ^-0 is output. That is, the slits Pa ^-6 and Pa ^-0 are spaced close to each other, and the starting position of the photoreceptor 1 is detected. Therefore, if the signal PA ^- 0 of the slit Pa ^- ₀ is detected while the output of MB26 is "H",
The AND gate 27 opens and outputs a signal SPS indicating the starting position of the photoreceptor via the inverter 28. The output of the inverter 28 is supplied to the set input terminal S of the flip-flop 29.
The flip-flop 29 has a set output terminal,
Outputs initial reset signal IRA. The reset input terminal R of the flip-flop 29 is supplied with an integral output from which power +V is supplied to an integral circuit consisting of a resistor and a capacitor via a switch 20 that directly detects the closing of the upper and lower parts of the copying machine main body. . The flip-flop 29 and the following flip-flops are set or reset when an "L" signal is supplied to each input terminal. In the integrating circuit of resistor R and capacitor C,
When input from the power plug 61, the power switch 2
1 and the door switch 22, and the power supply +V supplied via the detection switch 20 is applied thereto. Therefore, when the detection switch 20 detects separation of the copying machine main body, that is, an open state, its contact opens and the charge in the capacitor C is discharged through the resistor. "L" is supplied to the reset input terminal R of the flip-flop 29, and the flip-flop 29 is reset. In other words, a separated state has been detected.

Next, when the detection switch 20 detects closing, that is, the closing of the copying machine body, the connection point between the resistor R and the capacitor C of the integrating circuit gradually rises from "L" to "H" due to the supply of +V. Therefore,
The flip-flop 29 is released from the reset state and receives an "L" signal (SPS signal) at the set input terminal.
is set, and a signal "H" is output from the set output terminal.

Therefore, the flip-flop 29 outputs a detection signal related to the detection of the vertical separation of the copying machine main body by the detection switch 20.

Further, the output of the AND gate 27 is supplied to one input terminal of a NAND gate 30, and the output terminals A and C of a binary counter (hereinafter referred to as a counter) 31 are supplied to the other input terminal of the NAND gate 30. The output of a NAND gate 32 that inputs a signal is supplied. The counter 31 is a counter that is reset when the initial reset signal IRA is "L", and counts up by one when the output from the NAND gate 30 is "L". In other words,
The counter 31 counts every time the signal SPS is output. Therefore, when the counter 31 counts "5", the output terminals A and C become "H",
The output of the NAND gate 32 is inverted to "L" and subsequent counting is stopped. nand gate 32
The output of the inverter 33 becomes the signal ISB. This signal ISB is a signal that is inverted to "H" when the start position detection signal of the photoreceptor 1 is counted five times, and is used as a stop signal for the optical memory removing means.

On the other hand, the slit detection signal PA is input to the decimal counter 34 and counted. Decimal counter 3
4 includes a decoder, and the decoded output is used as a driving signal for each copying process. Decimal counter 34
is AND gate 3 with input signals IRA and SPS.
It is reset by a signal from slit signal PA-1, and when it counts six slit signals, it is reset and starts counting from slit signal PA ^-1 .

Signals and signals from the above decimal counter 34
Each copying process is controlled by ISB and IRA. In other words, control is performed to remove the optical memory of the photoreceptor 1. Examples of the drive circuit are shown in FIGS. 6a to 6f. In FIG. 6a, signal ISB is applied to the set input terminal of flip-flop 36, which provides the set output of flip-flop 36 to the base of transistor 37. The emitter of the transistor 37 is grounded, and the collector is connected to the power supply + via the main motor relay 38.
V ₀ is supplied. Also, flip-flop 3
The reset input terminal 6 is supplied with a signal (slit Pa ^-6 ) from the decimal counter 34 via an amplifier 39 and a differentiating circuit 40. When the signal ISB is "H", the flip-flop 36 is differentiated at the falling edge of the signal, and the reset input terminal becomes "L" and is reset. When the main motor relay 38 is supplied with power +V ₀ , it closes its contacts, and the main motor MM shown in FIG.
power is supplied to rotate the photoreceptor 1. At this time, the fixing roller 12 and the conveyance system are also rotated at the same time.

Also, in FIG. 6b, the signal from the decimal counter 34 is supplied to the set input terminal of a flip-flop 43 via an inverter 41 and a differentiating circuit 42. The signal is inputted together with the signal ISB to a NAND gate 44, and the output of this NAND gate 44 is supplied to the reset input terminal of the flip-flop 43 through an AND gate 45 which inputs the signal IRA to one input terminal. The set output of flip-flop 43 is supplied to the base of transistor 46, and
It controls the switching of 6. The emitter of the transistor 46 is grounded, and the collector is supplied with power +V via a relay 47 that supplies power to the high voltage generating circuit CHVU of the corona charger 2 shown in FIG.

Similarly, in FIG. 6c, in order to light the lamp CL of the illumination device 6 (see FIG. 5), its relay 50 is driven via the transistor 49 which is made conductive by the set output of the flip-flop 48. The set and reset input terminals of flip-flop 48 are supplied with the signals ISB and IRA through a circuit similar to that of FIG. 6b, surrounded by dotted lines.

In addition, the high voltage generation circuits THVU, DHVU and static elimination lamp DL of the transfer corona charger 8, the static elimination corona charger 10, and the optical static elimination device 11 in FIGS. 6d to 6f are as follows:
By setting each flip-flop 51, 54, 57, each transistor 52, 55, 5
Power supply + to each relay 53, 56 and 59 via 8
It is driven by supplying V ₀ .

In the circuit configuration as described above, the removal operation of the optical memory according to the present invention will be explained with reference to the time chart of FIG. Therefore, after opening the upper part 15 of the copying machine main body due to paper jam etc. and removing the jammed paper,
When the upper part 15 is closed to the lower part 16, the detection switch 20 is closed. At this time, even if the power switch 21 and the door switch 22 are open, the detection switch 20 is closed, so that the +V power is supplied to the resistor and capacitor circuit, and the reset state of the flip-flop 29 is released. The output Q of this flip-flop 29, that is, the signal IRA is at "L". At the same time, the counter 31
is reset and the signal ISB is inverted to "L", and at the same time the flip-flop 36 is set. Therefore, the main motor relay 38
The power +V ₀ from the outlet 61 can be supplied to the MM. Therefore, by closing the power switch 21 and door switch 22, the motor
MM rotates, causing the photoreceptor 1 to rotate. Due to this rotation of the photoreceptor 1, a slit signal PA is output through the synchronizing disk 23, and this is sent to the decimal counter 34.
will be counted. Therefore, the slit signal PA ^-6
is output and then PA ^- ₀ is output, MB2
6 outputs an "H" signal, AND gate 27 is opened and flip-flop 29 is set via inverter 28. At this time, the flip-flop 29 is set via the inverter 28. At this time, the gate 35 is opened by the output of the inverter 28, that is, the signal SPS and the set output signal IRA of the flip-flop 29, and the decimal counter 34 is reset. In other words, the rotation start position of the photoreceptor 1 is detected, and thereafter the operation of removing the optical memory of the photoreceptor is performed. This is to search for the start position of the photoreceptor 1 when the photoreceptor 1 is not stopped at the start position due to a paper jam or the like. The signal SPS that detects this start position is counted by the counter 31.
As a result, the counter 31 counts "1".

After the above, when the start position of the photoreceptor is detected, the decimal counter 34 is reset and starts counting the next slit signal. Therefore, when the image forming start tip corresponding to the start position of the photoreceptor 1 faces the corona charger 2 in synchronization with the rotation of the photoreceptor 1, the slit signal PA ^-1 of the disk 23 is output. This causes the decimal counter 34 to count and output a signal. In response to this signal, the flip-flop 43 is set, and the power +V ₀ is supplied to the relay 47 connected to the high voltage generating circuit CHVU, and the corona charger 2 uniformly charges the photoreceptor 1 from the leading edge where image formation starts.

Next, when the image forming start tip of the photoreceptor 1 reaches the exposure start position, the slit signal PA ^-2 is output.
The signal sets flip-flop 48 and energizes relay 50. Therefore, the exposure lamp CL is turned on and exposure is performed through the optical system. At this time, the document table 4 is not moved and is stopped at the initial position, and the light from the lamp 50 is transmitted to the photoreceptor 1.
The lower surface 4a of the original platen 4 is formed to cause diffused reflection so that the light is irradiated on the document table 4.

On the other hand, in the same manner as described above, each relay 53, 56, 59 is energized by the image formation start tip of the photoreceptor facing each of the transfer corona charger 8, the charge eliminating corona charger 10, and the optical charge remover 11. The above devices are driven in sequence. When the photoreceptor 1 rotates once and its start position (image formation start tip) reaches the start position, a signal SPS is output, which causes the decimal counter 34 to output a signal SPS.
will be reset. Further, since the output of the NAND gate 32 is always "H", the counter 31 receives a signal via the NAND gate 30 in response to the "H" signal from the AND gate 27, and counts this signal. At this time, the counter 31 counts "2" together with the earlier initial signal. here,
In the flip-flop 36 for driving the main motor relay 38, a reset signal is applied to the reset input terminal of the flip-flop 36 via the differentiating circuit 40 in response to a signal before the start position of the photoreceptor 1 is detected.
However, the signal ISB applied to the set input terminal of the flip-flop 36 remains "L" until the signal SPS is output five times and the counter 31 counts "5". is not reset,
The set state is maintained.

After that, the photoconductor 1 rotates, and if it rotates four times from the time when the first signal SPS was output, the counter 31
counts “5”. As a result, the output of the NAND gate 32 is inverted to "L", and the inverter 3
The signal ISB is inverted to "H" through the signal ISB. Therefore, the output of the NAND gate 32 becomes "L", and from now on, the start position signal SPS due to the rotation of the photoconductor is
The counter 31 never counts. This prevents malfunctions by not counting the rotation of the photoreceptor 1 during normal copying operations.

Subsequently, the signal ISB is inverted to "H", and since the photoreceptor continues to rotate, the starting position faces the corona charger 2, and a signal is output. As a result, the output of the NAND gate 44 becomes the signal
Since ISB is "H", it is inverted to "L", the reset terminal of the flip-flop 43 becomes "L", the flip-flop 43 is reset, and the operation of the corona charger 2 is stopped. Similarly, the lamp CL is turned off when the signal is received, the operation of the transfer corona charger 8 is stopped when the signal is received, the operation of the charge eliminating corona charger 10 is stopped when the signal is received, and the lamp CL is turned off when the signal is received.
DCL is turned off.

Photoconductor 1 continues to rotate and the slit signal is
When PA ^-6 is output, the accompanying signal is 10
It is output from the advance counter 34. This signal is applied to the reset input terminal of the flip-flop 36 via the amplifier 39 and the differentiating circuit 40, so that the flip-flop 36 is reset since the set input terminal is at "H". Therefore, the drive of the main motor relay 38 is stopped, the main motor MM is stopped, and the starting position of the photoreceptor 1 is brought to match the starting position and stopped. When the above-described operation is completed, the optical memory effect caused by opening the upper part 15 of the copying machine main body is removed.

In addition to paper jams, the upper part 15 of the copying machine main body is opened for maintenance and the like. in this case,
After opening the power switch 21 or the door switch 22, the upper part 15 and the lower part 16 are separated, and after the maintenance is completed, the upper part 15 and the lower part 16 are closed. This separation operation causes flip-flop 29
is reset when it is opened, and is set after the optical memory removal operation, detects the separation state at that time, and outputs the signal. Then, when the detection switch 20 and the power switch 21 or the door switch 22 are closed again, driving is performed to eliminate the optical memory effect described above. In other words, the reset terminal of flip-flop 29 is
The level becomes "L", and the flip-flop 29 for recognizing the open state is reset. Therefore,
When the signal IRA becomes "L", it is output as an open signal, and the above-described operation is executed in the same manner as the power is supplied by the closing operation of the copying machine main body.

By providing a differential circuit connected to the reset input terminal of the flip-flop 29, if the outlet 61 is unplugged, the flip-flop 29 is reset when the outlet 61 is inserted again. Therefore, power is supplied to the main motor MM, and if the power switch 21 and the door switch 22 are closed, the optical memory removal operation starts. In other words, when the outlet 61 is plugged in or unplugged, the optical memory removal operation is performed at the same time as the separation operation.

Therefore, the upper part 15 and lower part 16 of the copying machine main body
When performing optical memory removal only for separation of
A backup power source using a battery may be used as the power source +V in FIGS. 3 and 6. That is, by separating the detection switch 20, the detection switch 20 opens and closes, and in response to this opening and closing, the flip-flop 2
9 will be reset to remember the separation state. Therefore, the optical memory removal operation is executed by supplying power to the main motor MM, but
Even if the outlet 61 is unplugged, the flip-flop 29 is not reset and the optical memory removal operation is not executed.

In the above explanation, the photoreceptor 1 is rotated four times, and the corona chargers 2, 8, 10 and the lamp are rotated each time.
Although CL and DCL are driven, the number of times is not necessarily limited to this, as it changes depending on the conditions of various devices including the photoreceptor 1, the intensity of the external light 19, its irradiation time, the expected safety factor, etc. .

Further, in the above explanation, the corona charger 2 is driven to uniformly charge the photoreceptor 1 to the polarity required for image formation, and then so-called uniform exposure is performed, but the charged charges are discharged by this exposure. . However, in order to charge the photoreceptor 1 to the polarity required for image formation,
Even if the corona charger 2 is not driven, the transfer corona charger 8 may be driven. Therefore, at least the corona charger 8 for transfer and the corona charger 1 for neutralization are provided.
0 and optical static eliminator 11, the object of the present invention can be achieved. In other words, the corona charger 2 and the lamp CL need not be driven by the signal from the decimal counter 34, and the circuits shown in FIGS. 6b and 6c can be omitted.

Next, an example will be described.

Organic semiconductor photoreceptor 1 as external light 19
After irradiating at 3000 lx for 5 minutes, it was rotated at a circumferential speed of 150 mm/sec. When this photoreceptor 1 was charged with a corona charger 2 with a discharge voltage of 7.2 k and a current of 1.2 mA, its surface potential increased to 40 to 60% of the charged potential of 500 V before irradiation due to the optical memory effect. decreased.

Subsequently, for optical memory removal according to the present invention,
Corona charger for transfer 8, corona charger for charge removal 10
After driving the optical static eliminator 11 and rotating the photoreceptor once, driving the corona charger 2 in the same manner as described above,
Upon charging, the surface potential of the photoreceptor was restored to approximately 85%.

After repeating the above operation four times, the surface potential of the photoreceptor is restored to about 95% by charging in the same way, and even if copies are made at this point, the quality is almost the same as before irradiation. No difference was observed.

As explained hereinafter, according to the electrophotographic copying machine of the present invention, in connection with the separation operation of the copying machine where external light is irradiated and optical memory is generated on the photoreceptor, by detecting the closed state of the copying machine rather than the open state, Since the optical memory removal means is driven in conjunction with the power supply to the copying machine main body, there is no need to provide a special means for detecting optical memory generated on the photoreceptor in the copying machine, and the copying machine main body is used for jam processing, etc. Optical memory can be reliably removed not only when separating for maintenance or other reasons.

In particular, if the separation of the copying machine body is detected reliably and the optical memory removal means is driven only when this separation is detected, and no optical memory is generated, the above-mentioned unnecessary driving can be eliminated, making it more effective. Optical memory can be removed.

Therefore, when using the copying machine, the main body of the copying machine is always kept in a normal state, and the copying quality after opening and the copying before opening can be maintained at the same quality.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of an electrophotographic copying machine according to the present invention, FIG. 2 is an external view showing the main body of the copying machine separated into upper and lower parts, and FIG. 3 is a control circuit for removing an optical memory according to the present invention. A circuit diagram showing one specific example, FIG. 4 is a plan view showing an example of a synchronous disk, FIG. 5 is a power supply circuit configuration diagram showing an example of the power supply according to FIG. 3, and FIGS. 6 a to f. 7 is a circuit configuration diagram showing an example of a drive circuit for driving each copying process, and FIG. 7 is a time chart for explaining the operation of FIGS. 4 and 6. 1: Photoreceptor, 2: Corona charger, 6: Illumination device, 8: Corona charger for transfer, 9: Copy paper, 1
0: Corona charger for static elimination, 11: Optical static eliminator, 1
5, 16: Upper and lower parts of the copying machine body, 17: Spring, 19: External light, 20: Detection switch, 2
1: Power switch, 22: Door switch, 38:
Main motor relay, 47, 53, 56: Relay for driving high voltage generation circuit, 50, 59: Relay for driving lamp, 60: Power supply circuit, 61: Outlet,
MM: Main motor, CHVU, THVU,
DHVU: High voltage generation circuit, SPS: Photoconductor start position signal, IRA: Initial reset signal,
ISB: (5 pieces) count signal of signal SPS.

Claims (1)

[Scope of Claims] 1. A photoreceptor, an image forming means disposed around the photoreceptor for repeatedly forming images on the photoreceptor, and a device that houses the photoreceptor and the image forming means and is capable of substantially copying. a copying machine main body configured to be separable along a paper conveyance path; means for cutting off power supply to the image forming means by opening the top and bottom of the copying machine main body; A means for supplying power to some circuits regardless of whether the machine body is opened up or down, and a means for detecting when the copying machine body changes from an open state to a closed state in connection with the separation operation of the copying machine main body. a detection means that is supplied with power by the power supply means and outputs a signal in response to detection of a separated state of the copying machine; and irradiation of external light to the photoreceptor in connection with separation of the copying machine main body. In order to remove the optical memory generated by the above, the photoreceptor is driven to rotate a plurality of times, and the rotating photoreceptor is charged, and a part of the image forming means is operated to remove the charged charge. and a control means for energizing the optical memory removing means in response to power supply to the image forming means after the copying machine main body is in the closed state, and outputting a detection signal from the upper and lower separation by the detecting means. An electrophotographic copying machine characterized by: