JPH06105365B2 - Copier control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a copying machine, which forms an electrostatic latent image on a photoconductor, develops the electrostatic latent image, and transfers the image onto recording paper. is there.

[Prior Art] As is well known, in this type of copying machine, a photoconductor is charged to provide photosensitivity.

An electrostatic latent image is created by exposing the photoreceptor to a light image.

Develop the electrostatic latent image with toner.

The developed image is transferred to recording paper.

Clean the photoconductor.

The image read from the original is recorded on the recording paper by executing the series of steps described above.

Further, in a multicolor copying machine, the image of the original is color-separated, and the above-described series of steps of charging, exposure, development, transfer, and cleaning are repeatedly performed for each color-separated image, and the image of each separated color is the same. The same multicolor print as the image of the original is obtained by superposing on the recording paper.

In such a single-color or multi-color copying machine, in order to match the positional relationship between the original image and the copied image, or the positional relationship of each color, the image scanning start timing of the optical scanning mechanism that is moved along the original image surface. It is necessary to exactly match the electrostatic latent image formation start position on the photoconductor and the transfer start position on the recording paper.

Therefore, in this type of copying machine, the light source, the movable mirror, the photosensitive drum, the transfer drum, and the like need to be accurately driven at a predetermined timing to form an image. A control device for controlling is provided.

Here, FIG. 24 is a schematic configuration diagram showing a configuration of a conventional multicolor copying machine. In the figure, the document table 1 is provided on the upper surface of the main body 101.
02 is provided, and a scan unit 103 is provided below the original table 102. Scan unit 103
Is composed of a lamp 104, first and second mirrors 105 and 106, a filter / lens unit 107, third and fourth mirrors 108 and 109, etc., and the lamp 104 and the first mirror 105 are integrated into the drawing.
It is configured to be movable in the A and B directions. Further, the second mirror 106 is configured to move at a speed that is half of the speed of the lamp 104 and the first mirror 105, corresponding to the movement of the lamp 104 and the first mirror 105.

Then, when copying is performed, first, when the lamp 104 and the first mirror 105 are moved in the direction of arrow A, the surface of the photosensitive drum 111 that is rotationally driven in the clockwise direction is irradiated with an optical image. In this case, the filter / lens unit 107 is switched so as to transmit light other than the yellow color, and the photosensitive drum 111 is charged in advance by the charger 112, so the optical image is the surface of the photosensitive drum 111. At, the electrostatic latent image corresponds to the yellow color of the original. And
Yellow toner is attached to the electrostatic latent image by the developing unit 113, whereby a yellow toner image is formed on the photosensitive drum 111.

On the other hand, the paper delivered from the paper cassette 114 is wound around the transfer drum 115 rotating counterclockwise and conveyed between the photosensitive drum 111 and the transfer drum 115, whereby the yellow toner image is transferred to the transfer drum 115. Transferred to the upper paper. Then, the surface of the photosensitive drum 111 is sequentially cleaned by the cleaning device 116 from the portion where the transfer is completed.

When the transfer of the yellow toner image is completed as described above, next, the filter / lens unit 107 is switched so as to transmit a color other than magenta, and the developing section 117 for magenta is selected. Then, the filter / lens unit 107 is switched so as to transmit a color other than cyan, and the developing section 118 for cyan is selected to perform the same transfer operation. When the transfer of the three primary colors is completed in this way, a composite image of each color of yellow, magenta, and cyan is formed on the surface of the paper on the transfer drum 115. Next, the sheet on the transfer drum 115 is fixed to the fixing device 12 by the belt 121.
The color image formed on the surface of the sheet by being conveyed to the sheet 2 by the fixing device 122 is reliably fixed to the sheet. Then, the fixed paper is ejected to the tray 123, whereby the series of color copying operations is completed.

FIG. 25 is a perspective view showing the outline of the position control mechanism of each movable part in the copying machine described above. Reference numeral 131 shown in the figure is a chain to which the driving force of a motor (not shown) is transmitted, and meshes with the sprocket 133. 132, sprocket 13
3 is a shaft to which the gear 134 is attached with the same axis center, and 135 is a shaft to which the transfer drum 115 and the gear 136 are attached. In the above configuration, when the sprocket 133 rotates, the gear 134 and the photosensitive drum
Gear that meshes with gear 134 as 111 rotates
136 rotates and the shaft 135 rotates, which causes the transfer drum 115 to rotate. In this case, the gears 134 and 136 have the same pitch diameter, and as a result, the photosensitive drum 111 and the transfer drum 115 rotate in opposite directions at the same speed and synchronously. Also, on the transfer drum 115,
The paper winding position is constantly controlled by the claw 137 for controlling the paper winding position.

On the other hand, the shaft 132 is attached to the pulley via the bearing 141.
142 is pivotally supported. A movable claw (not shown) driven by a solenoid or the like is provided on the pulley 142 side, and when the claw is driven to engage a pin 143 provided on the sprocket 133, the rotation of the shaft 132 is changed to the pulley.
142 is transmitted to the photosensitive drum 11 by the pulley 142.
It is designed to rotate synchronously in a predetermined relationship with 1. The rotation of the pulley 142 is transmitted to the pulley 148 via the wire 144, and the rotation of the pulley 148 is transmitted to the scan unit 103 via the shaft, the pulley, the wire, and the like. As a result, when the pulley 142 rotates, the lamp 104 and the like move in the direction of arrow A corresponding to the rotation of the photosensitive drum 111. When the driving claw is disengaged from the pin 143, the lamp 104 and the like are returned in the arrow B direction by the urging force of a spring (not shown).

According to the above-mentioned configuration, since the scan unit 103 and the photosensitive drum 111 are mechanically interlocked with each other, the position of the electrostatic latent image formed on the photosensitive drum 111 becomes constant,
Further, since the photosensitive drum 111 and the transfer drum 115 are synchronously rotated in opposite directions and the winding position of the paper on the transfer drum 115 is constant, the positions of the images of the respective colors transferred on the paper are the same. As a result, color copying is normally performed by multi-color printing without causing color misregistration.

However, if the positions of the images of the respective colors transferred onto the paper are misaligned, color misregistration occurs and the finish becomes difficult to see. Therefore, the scan unit 103 and the photosensitive drum 111
Also, the drive position relationship of the transfer drum 115 needs to be controlled extremely accurately.

However, in the above-mentioned control device, since the moving parts are all interlocked mechanically, the initial position of each part of the moving part may fluctuate due to aging, etc., and as a result, the formation position of the electrostatic latent image, etc. However, there is a drawback in that the color shift occurs and the color shift occurs.

Therefore, in order to prevent such color misregistration and the like, a scanning unit that is movably provided on a predetermined linear trajectory, a photosensitive drum that rotates in a predetermined relationship with the movement of the scanning unit, and a photosensitive drum A drive motor is provided for each of the transfer drums that rotate in a predetermined relationship, and the scanning unit, the photosensitive drum, and the transfer drum are configured to be individually driven by the drive motors. On the other hand, there has been proposed an apparatus in which pulse encoders for detecting the amount of rotation thereof are provided, and each of the drive motors is controlled based on the output of the pulse encoder.

According to such a device, the occurrence of color misregistration can be reliably prevented, and since the scanning unit, the photosensitive drum, and the transfer drum are interlocked with each other by electrical timing, there is no secular change in the positional relationship between them, and it is complicated. It is possible to easily reduce and enlarge originals without the need for a special mechanical mechanism.
Further, there is an advantage that the efficiency of copying can be improved by adopting the short scan or the like.

[Problems to be Solved by the Invention] However, in the above-described configuration, the transfer drum has the transfer start point and the latent image formation start point based on the grip timing signal of the transfer sheet output in synchronization with the rotation of the drum 6. Acceleration / deceleration control is performed so that and coincide with each other.

However, the sensor for generating the timing signal has low accuracy, and a 1: m gear is usually interposed between the motor as a power source and the transfer drum. Therefore, there is a problem that the transfer start point and the latent image formation start point are deviated from each other.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device for a copying machine, which can match the latent image formation start point and the transfer start point with high accuracy.

[Means for Solving the Problems] The present invention provides a pulse generating means for generating a pulse signal in synchronization with the rotation of the transfer means, and a timing signal representing the grip timing of the transfer paper in synchronization with the rotation of the transfer means. A timing pulse generating means for generating and a control means for counting the pulse signal after generation of the timing signal, recognizing a time point when the count value reaches a predetermined value as a reference point up to a transfer start point, and controlling a transfer operation. And are provided.

[Operation] The control means counts the pulse signal after the generation of the grip timing signal, recognizes the time when the count value reaches a predetermined value as a reference point up to the transfer start point, and controls the transfer operation. In this case, since the pulse generating means is composed of high-precision pulse generating means such as a rotary encoder, its accuracy is high. Therefore, the latent image formation start point and the transfer start point can be matched with high accuracy.

[Examples] Hereinafter, the present invention will be described in detail based on Examples.

FIG. 1 is an overall configuration diagram of a three-color separation type multicolor copying machine to which the present invention is applied. In the figure, 1 is a drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) which is rotationally driven around an axis 2 in a direction of an arrow at a peripheral speed V, 3 is a charger for imparting photosensitivity to the photosensitive drum 1, Reference numeral 4 denotes an exposure unit, and 5Y, 5M, and 5C are color toner developing devices corresponding to decomposed light, and in the case of this embodiment, yellow, magenta, and cyan color toner developing devices, respectively. Reference numeral 6 is a transfer drum, and 7 is a photosensitive drum cleaner.

Reference numeral 8 denotes a document placing table, and the document G is placed on the table 8 with its image surface facing downward. Reference numeral 9 denotes an original scanning optical system that exposes the photosensitive drum 1 below the original table 8.
Along the lower surface, from the left side of the table to the right side of the table, reciprocating at the same speed as the peripheral speed V of the photosensitive drum 1 together with the document illumination lamp 10 as an exposure light source, scans the downward document surface on the table 8 through the table 8. 1/2 of the peripheral speed of the first moving mirror 11 and the photosensitive drum 1
The second and third mirrors 12 and 13 reciprocating at a speed of 4 and a fixed mirror 14, and a print start button (not shown)
When is pressed, the moving optical systems 10 and 11 reciprocate to scan the original image sequentially from the left to the right through the table 8, and the scanning light L thereof is the first mirror 11 → the second mirror 12 → the third mirror. 13 → 4th
Images are sequentially formed on the path of the mirror 14 by the exposure unit 4 on the surface of the photosensitive drum 1 which is rotationally driven.

Reference numeral 15 is a color separation filter device, and four filters of a blue light transmission filter 15B, a green light transmission filter 15G, a red light transmission filter 15R, and a neutral filter 15N are radially attached and held at 90-degree intervals with respect to the rotation axis. Each filter is positioned in the optical path of the scanning light L by rotationally driving the rotation axis by 90 degrees. Also,
The filter device 15 and the color developing devices 5Y, 5M and 5C are associated with each other, and when the blue filter 15B is switched in the optical path of the scanning light L, the yellow toner developing device 5Y and the green filter 15G are connected. In this case, the magenta toner developing device 5M operates, and in the case of the red filter 15R, the cyan toner developing device 5C operates.

On the other hand, the transfer drum 6 is rotationally driven around the shaft 16 in the direction of the arrow at the same peripheral speed as the photosensitive drum 1, and the transfer paper sent from the paper supply unit (not shown) to the drum 6 is grippered. The drum 6 is held by the drum 6, and rotates together with the drum 6 while being wound around the peripheral surface of the drum 6.

Therefore, when the document G is set on the table 8 and the print start button is pressed, a series of image forming processes of charging, exposing, developing, transferring, and cleaning are repeatedly executed for each color separation image of the document to create a color print. To be done.

In this case, the print start button starts the image forming process for the first color separation image, but the second
For the color and the third color, the image forming process is started by generating a print restart signal in the internal circuit when the previous process is completed.

That is, assuming that the color separation is performed in the order of blue, green, and red, the blue filter 15B intervenes in the exposure optical path during the first image formation, and the yellow toner developing device 5Y operates, The blue component image of the original image is formed on the photosensitive drum surface as a yellow toner image having a complementary color relationship with blue, and the yellow toner image is transferred onto the transfer paper surface wound around the peripheral surface of the transfer drum 6.

At the time of the second image formation, the green filter 15G intervenes in the exposure optical path and the magenta toner developing device 5M operates so that the green component image of the original image is exposed as a magenta toner image having a complementary color relationship with green. Formed on the drum surface, the magenta toner image is transferred to the yellow toner image first,
Further, it is continuously superposed and transferred onto the transfer paper surface wound around the drum 6.

At the time of the third image formation, the red filter 15R intervenes in the photosensitive optical path, and the cyan toner developing device 5C operates so that the red component image of the original image is a cyan toner image having a complementary color relationship with red. The cyan toner image is formed on the transfer paper surface onto which the yellow and magenta toner images have already been transferred.

In this manner, the same multicolor image as the original image is compositely formed on the transfer paper surface by the superimposed transfer of the toners of the respective colors. After the repeated transfer process is completed, the transfer sheet held on the drum 6 is separated from the drum 6 and sent to a fixing device (not shown) by a conveying device (not shown) to be fixed. , Multi-colored print is output from the output tray.

The moving optical system, the photosensitive drum 1, and the transfer drum 6 described above.
Are powered by independent motors for movement or rotation. That is, the power source of the moving optical systems 10 and 11 is given by the motor 18 (hereinafter referred to as the CRC motor 18) via the pulley 19 and the wire 20. Also,
The power source of the photosensitive drum 1 and the transfer drum 6 is a motor 21.
(Hereinafter, PR motor 21) and motor 22 (hereinafter, TR motor)
22) respectively. And these CRG
Motor 18, PR motor 21, TR motor 22 are servo controllers
Controlled by 23. The servo controller 23 is further controlled by a master controller 24 as its upper control means. The master controller 24 uses the signals described below.
Upon receiving the IMS and PRZ signals and the like from the servo controller 23, the control of the entire copy cycle and the abnormality diagnosis processing are executed. The servo controller 23 and the master controller 24 are connected by a serial data line 25 in addition to the above signal lines.

On the other hand, pulse generators 26, 27, 28 for generating pulse signals synchronized with the rotations of the respective motors are attached to the respective rotary shafts of the CRG motor 18, the PR motor 21, and the TR motor 22. That is, as shown in detail in FIG. 2, the rotary shaft of the CR motor 18 has a rotary encoder 26A that generates a rotation pulse signal CRZ indicating that the motor 18 has made one rotation, and a predetermined rotation angle of the CRZ motor 18. A pulse generator 26 including a rotary encoder 26B for generating a pulse signal CRB for each and a rotary encoder 26C for generating a pulse signal CRA having a phase difference of 90 degrees from the signal CRB is attached. Similarly,
As shown in detail in FIG. 3, the rotary shaft of the PR motor 21 includes a rotary encoder 27A that generates a rotation pulse signal PRZ indicating that the photosensitive drum 1 has made one rotation, and the PR motor 21.
A pulse generator 27 including a rotary encoder 27B for generating one pulse signal PRB for each predetermined rotation angle and a rotary encoder 27C for generating a pulse signal PRA having a phase difference of 90 degrees from the signal PRB is attached. . In this case, PRO of the photosensitive drum 1 in FIG. 3 is the rotation start point of the drum 1, and the encoder 27A is attached so that the signal PRZ is generated at the rotation timing substantially corresponding to this rotation start point PRO. 1MO is the starting point of electrostatic latent image formation, and P
It is at a position that is offset from the RO by α degrees.

Further, as shown in FIG. 4 in detail, the rotating shaft of the TR motor 22 is one per rotation of the motor 22 (however, the TR motor is
Since there is a deceleration mechanism between the transfer drum 6 and the transfer drum 6, a rotary encoder 28A that outputs pulse signals TRZ of 6 per rotation of the transfer drum 6 at equal intervals, and a predetermined rotation angle of the TR motor 22. A pulse generator 28 including a rotary encoder 28B for generating one pulse signal TRB and a rotary encoder 28C for generating a pulse signal TRB having a phase difference of 90 degrees from the signal TRB is attached. Further TR motor 22
An actuator 6A protruding from a portion corresponding to the position of the gripper 17 is provided on the inner peripheral surface of the transfer drum 6 driven by, and the sensor 6B fixed to the frame is operated to generate a grip timing signal of the transfer paper. It is configured to eject the TRS.

In the following, the pulse generator including the actuator 6A and the sensor 6B is referred to as a TR sensor 60. Servo controller
The 23 counts the output signal of the encoder 28B or 28C with reference to the output signal TRS of the TR sensor 60 to predict the grip timing of the transfer paper, and the grip position at the predicted timing is the transfer start point PO.
The time (distance or time) required to reach is reached, and the speed of the TR motor motor 22 is accelerated or decelerated so that the latent image formation start point IMO and the transfer start point PO match.

In FIG. 1, a switch 29 provided at a position separated from the home position of the moving optics 10 and 11 in the operation direction by a predetermined distance detects the scanning start timing of the image. , REG sensor) 29 is used as the scanning start timing.

FIG. 5 is a block diagram showing the detailed configuration of the servo controller 23, which is roughly classified into CRG motor 18, PR motor 21, and TR.
The system is composed of three systems of synchronous servo circuits 30, 31, 32 for independently controlling the rotation state of the motor 22 to a target rotation state, and a control circuit 33 for controlling these in a predetermined synchronization relationship.

The synchronous servo circuits 30 to 32 will be described by taking the synchronous servo circuit 30 of the CRG motor 18 as a representative. The direction discriminator 300, the OR gates 301 and 302, the FV converter 303, the synchronous compensator 304, FV.
Converter 305, error amplifier 306, direction discriminator 307, overcurrent detector
308, a PWM chipper 309, and its control circuit input is composed of A-phase and B-phase signals output from the speed command generator 330 of the control circuit 33 with a phase difference of 90 degrees. The speed command pulse SCP, the position pulse PP composed of the UP signal and the POWN signal output from the position command generator 331 of the control circuit 33, and the gate off pulse GOFF for shutting off the output gate of the PWM checker 309 are input. ing. Further, as an output to the control circuit side, the overcurrent detection signal of the overcurrent detector 309 and the rotation direction of the CRC motor 18 detected by the direction discriminator 307 are either forward rotation (UP) or reverse rotation direction (DOWN). The rotation direction detection signals RPU and RPD indicating that are output.
Further, the output signal CRZ of the pulse generator 26A is output to the control circuit 33 side as it is. These signals RPU, RPD, and CRZ are input to the optical system position detector 332 of the control circuit 33, so that the image scanning positions of the moving optical systems 10 and 11 are detected. Further, the overcurrent detection signal OC is sent to the control circuit 33.
Microprocessor (CPU) 33 through OR gate 333
When the CRG motor 18 is input as an interrupt signal of 4 and an overcurrent flows in the CRG motor 18, an emergency stop control of the CRG motor 18 is performed by the interrupt processing of the CPU 334. The OR gate 333 is also input with overcurrent detection signals of the PR motor 21 and the TR motor 22.

In this case, since the PR motor 21 does not perform position control but only speed control, no position control pulse is input to the synchronous servo circuit 31, and the speed command SCP (P)
Only input from the speed command generator. Further, regarding the TR motor 22, since it is necessary to perform acceleration / deceleration control of the TR motor 22 in order to match the transfer start point with the latent image formation start point as described later, the speed command pulse SCP (T) and the position The command pulse PCP (T) is input from the acceleration / deceleration command generator 336.

Further, in order to perform the acceleration / deceleration control in this case, the rotation direction detection signals RPU, PPD of the TR motor 22 and the output signal TRZ of the pulse generator 28A are input to the transfer drum rotation angle detector 337, and the TR drum is detected by these signals. The current rotation angle of 6 is detected. Then, the rotation angle detection signal causes the CPU 334 to generate an acceleration / deceleration command pulse from the generator 336 such that the transfer start point and the latent image formation start point coincide with each other.

Although the basic operation of the control circuit 33 is controlled by the CPU 334, the CPU 334 executes the control operation based on the control program and control parameters stored in the ROM 335, 336 or the RAM 337. In this case, the number of copies, paper size,
Switch for setting well-known copy mode such as reduction / enlargement ratio, copy start switch, error indicator lamp,
Since the operation panel provided with switches and the like for setting diagnostic commands for maintenance and inspection is connected to the master controller 24, information on these various switches is sent to the master controller 24 via the serial data input / output port 338. It is designed to be sent and received between people.

The operation of the synchronous servo circuit of the CRG motor 18 will be described representatively as follows.

First, if only the speed command pulse SCP (C) is input without giving the position command pulse PCP (C), the pulse SCP
The direction discriminator 300 is determined by the phase difference between the A phase and the B phase in (C).
Discriminates the rotation command direction and generates a command pulse SPA corresponding to the command direction. That is, in the case of the forward rotation direction, the period corresponding to the target speed commanded by the speed command pulse
Outputs SPA, and outputs SPB with a cycle corresponding to the same target speed in the case of reverse rotation.

Of these signals, the signal SPA is sent through the OR gate 301 to the synchronization compensator 30.
4 and the FV converter 303. Further, the signal SPB is input to the synchronization compensator 304 via the OR gate 302 and the FV converter 303.

When the signal SPA or SPB is input, the FV converter 303 converts the signal into a voltage signal corresponding to the cycle, and inputs the voltage signal to the error amplifier 306 as a speed command.

On the other hand, the synchronization compensator 304 is configured to convert the up / down counter and its count value into an analog signal, and then perform non-linear conversion using a route amplifier, and input the analog signal to the error amplifier 304 as a synchronization error signal. The output signal of the OR gate 301 is input to the up count input of the up / down counter, and the output signal of the OR gate 302 is input to the down count input.

Therefore, speed command pulse SCP (C) corresponding to the target speed
Is input, the speed command of voltage corresponding to the cycle of the pulse SCP (C) and the synchronization error signal are input to the error amplifier 306. Therefore, the error amplifier 306 controls the conduction angle of the PWM chopper 309 by these input signals,
A current corresponding to the target speed is applied to the CRG motor 18. As a result, when the CRG motor 18 starts to rotate, the pulse generators 26A, 26B input signals CRA, CRB having a cycle proportional to the rotation speed thereof.

Then, the direction discriminator 307 outputs the pulse signal RPU or RPD corresponding to the current rotation direction of the CRG motor 18 by the phase delay of these signals CRA and CRB and having a cycle proportional to the rotation speed. . The signals RPU and RPD are input to the FV converter 305, converted into a voltage signal corresponding to the cycle, and input to the error amplifier 306 as a speed feedback signal. Thus, the deviation between the speed command voltage signal and the speed feedback signal is detected by the error amplifier 306, and the output current of the PWM chopper 309 is controlled so that the deviation becomes zero. On the other hand, the output signal RPU of the direction discriminator 307 is input to the OR gate 302, and the RPD is input to the OR gate 301. As a result, when the CRG motor 18 starts to rotate in the normal direction, the signal RPU is input to the down count input of the synchronization compensator 304. On the contrary, when the rotation starts in the reverse direction, the signal RPD is input to the up count input. For this reason, C
The count value gradually decreases as the RG motor 18 rotates, but since the analog-converted voltage of the count value is input to the error amplifier 306 as a synchronization error signal, the output current of the PWM chopper 309 also depends on this synchronization error signal. It is variable. As a result of such control, the CRG motor 18 rotates at a phase synchronized with the speed command pulse SCP (C) and at a speed corresponding to the command speed.

On the other hand, when the phase command pulse PCP (C) is input, the phase of the pulse PCP (C) and the output pulse RP of the direction discriminator 307
An error voltage corresponding to the deviation from the phase of U or RPD is output from the synchronization compensator 304, and C is set so that the error voltage becomes zero.
The position of the moving optical system is controlled to the target position by changing the output current to the RG motor 18.

In the above-mentioned configuration, a series of copying cycles of the following steps are executed. That is, FIG. 6 shows the rotation angles θCRG, θP of the CRG motor 18, PR motor 21, and TR motor 22.
7 is a time chart showing R and θTR and their synchronization relationships, where the horizontal axis represents time and the vertical axis represents rotation angle.

First, if the PR motor 21 is activated and the signal PRZ is generated, the CRG motor 18 is activated after t time. Then, the moving optical system reaches the position of the REG sensor 29, and the sensor 2
When the scanning start timing signal SNSR is output from 9, the electrostatic latent image is sequentially formed from the electrostatic latent image formation start position IMO of the photosensitive drum which is defined by the generation timing of this signal.
On the other hand, the TR motor 22 that is the power source of the transfer drum 6 is started almost at the same time as the PR motor 21, but at the timing T when the signal SNSR is output, the time until the grip timing signal TRS of the transfer sheet is generated. Is predicted and calculated, and if the rotational speed V _PR of the transfer drum 6 is a speed at which the latent image formation start point IMO and the transfer point PO coincide with each other based on the predicted value, , Is accelerated in the same acceleration state. However, when it is determined that the time to the signal TRS is shorter than the normal value as shown by the speed change line iii, that is, when the grip timing of the transfer paper is determined to be too early, it is necessary to match the normal timing. control is started to decelerate the speed of the motor 22 after t _P time. On the contrary, as shown by the speed change line ii, the signal TRS
If the time until is longer than the normal value, the acceleration control of the TR motor 22 is started after t _P time so as to match the normal timing. This acceleration / deceleration control is performed by changing the cycle of the acceleration / deceleration command pulse output from the acceleration / deceleration command generator 336 shown in FIG.

As a result, the latent image formation start point IMO and the transfer start point PO coincide with each other, and an image having no color shift is transferred and formed. In multicolor copying, such a process is repeated three times to form a multicolor print.

Next, in order to form a multicolored print without color shift,
As described above, in addition to the position control of the transfer start point by the acceleration / deceleration control of the TR motor 22, the synchronous control of the PR motor 21 and the CRG motor 18 and the position for starting the movement of the moving optical system from the regular home position Control, control of the starting position of PR motor 21 and TR motor 22 to match the latent image formation start point IMO and scanning start timing, and also when an abnormal condition such as when signals PRZ and TRZ are not output Need to control.

Hereinafter, the control contents will be described in detail for each control item.

(1) Position Control of Moving Optical System As described above, the moving optical system transmits power for movement through the wire and the pulley. Therefore, when returning the moving optical system to the stop position (starting position at the time of copying start), the stop position of the moving optical system shifts for each copy cycle due to the state change of the power transmission mechanism and the like, and the copy is restarted. When this happens, the run-up distance of the moving optical system becomes different, and the positional relationship between the original image and the copied image or the positional relationship between the respective colors does not match, resulting in a color shift in the multicolor copying machine. Therefore, in order to prevent such color misregistration, it is necessary to constantly control the stop position of the moving optical system to the regular stop position.

Therefore, in the embodiment of FIG. 1, the measuring means for measuring the time from the actuation timing of the REG sensor 29 to the stop of the moving optical system by counting the rotation pulse signal CRB or CRA is an internal servo controller 23. It is provided in. Specifically, it is incorporated in the control program of the CPU 334. Then, the measurement using this measuring means is carried out at every predetermined time, such as immediately before the start of copying the first sheet or immediately before shifting to a series of copying cycles.

Specifically, at any of the above times, the moving optical system
10 and 11 are moved in the scanning direction of the original image, and the generation timing of the output signal SNSR of the REG sensor 29 that operates when the optical system returns to the stop position is used as a reference, and as shown in FIG. measuring the time N _D to the generation timing of the reference signal CRZ.

Then, when the optical systems 10 and 11 return to the stop position, the reference signal C
The from RZ occurs _{N S = C-N D ...} (1) to become time measured by the rotation pulse CRA or CRB,
After generation after N _S time of the signal CRZ stopping the CRG motor 18.

As a result, the position where the REG sensor 29 operates and the optical system 10,
The distance from the stop position of 11 is always controlled so that N _S + N _D = C.

As a result, even if the power transmission mechanism such as the wire 20 for moving the moving optical system changes in state, the starting positions of the optical systems 10 and 11 are always the same, and the positional deviation or color deviation of the copied image is eliminated.

(2) Controlling the start position of the PR motor and TR motor On the peripheral surface of the transfer drum 6, as shown in FIG. 4, a plastic net 61 for electrostatically adsorbing the transfer paper corresponds to the maximum length of the transfer paper. It is formed only for the length. By the way, if the image forming area of the photosensitive drum 1 is stopped at the portion of the plastic net 61, a transfer abnormality, that is, a so-called interruption occurs at the time of transfer. Therefore, it is necessary to stop and control the PR motor 21 and the TR motor 22 so that the electrostatic latent image forming area of the photosensitive drum 1 and the plastic net 61 do not match.
Further, this relationship needs to be returned to the normal positional relationship even when the relationship between the two is deviated due to a paper jam.

Therefore, in this embodiment, the PR motor 21 and the TR motor 22 are started before the start and end of a series of copying cycles, and the signal PRZ
The signal PRA (or PRB) and the signal TRA (or TRB) are counted with reference to TRS and TRS respectively, and when the electrostatic latent image forming area and the plastic net 61 are in a positional relationship such that they do not overlap, the PR motor 21 and TR By stopping the motor 22, the start position relationship between both motors is controlled.

That is, for the PR motor 21, as shown in the time chart of FIG. 8, the signal PRA (or
PRB) is counted, the PR motor 21 is stopped when the count value reaches a predetermined value N _stP , and the TR motor 22 has a signal TR as shown in the time chart of FIG.
The signal TRA (or TRB) is counted from the generation timing of the signal TRZ that first appears after the rise of S, and the count when the PR motor 21 is stopped after the gripper 17 reaches the count value N _P0 that passes the transfer point PO The TR motor 22 is controlled so as to be stopped when the count value "N _PO + N _STP " obtained by adding the value N _STP is reached.

As a result, the photosensitive drum 1 and the transfer drum 6 are controlled in a positional relationship such that the electrostatic latent image forming area and the plastic net 61 do not overlap each other. Then, this position control is performed immediately before and at the end of a series of copying cycles.

Therefore, even if a paper jam or the like occurs and the positional relationship between the photosensitive drum 1 and the transfer drum 6 is deviated, after the paper jam is removed, the positional relationship is controlled to be normal and a multicolor copy image with good image quality is formed. It

(3) Start-up synchronization control of the moving optical system and the photosensitive drum When the start-up timing of the moving optical system and the photosensitive drum 1 is out of sync, the exposure point IMO shifts, so the photosensitive drum surface in the electrostatic latent image forming area Since the degree of fatigue of partially varies, density unevenness occurs and the image quality deteriorates. Conventionally, time is measured starting from the start timing of the moving optical system, and when the measured time reaches the copy start time of the next color, the moving optical system is started again and an electrostatic latent image of the next color is formed. However, in this case, the synchronous relationship between the moving optical system and the photosensitive drum 1 may be changed in each copying cycle depending on the unevenness of the rotation cycle of the photosensitive drum 1 and the accuracy of the soft timer for timing. There is a problem in that the deviations are accumulated, and the deviations are accumulated to further increase the density unevenness for each color.

Therefore, in the present embodiment, the signal P
A counter for counting RA or PRB is provided inside the servo controller 23, and as shown in the time chart of FIG. 10, the rotation angle θ _B of the photosensitive drum 1 indicated by the count value of this counter reaches a constant rotation angle L1. The moving optical system is activated each time.

By doing so, even if the rotation cycle of the photosensitive drum 1 becomes uneven, the generation position of the signal PRZ and the latent image formation start point IMO are set to the third value.
As shown in the figure, as long as the relationship of α degrees is maintained, the synchronous relationship between the moving optical system and the photosensitive drum 1 is always kept constant, and a copy image without density unevenness can be obtained.

(4) Transfer start position control As described above, the transfer drum 6 outputs six signals TRS per one rotation of the drum 6 and the output direction SNSR of the REG sensor 29.
The transfer start point PO and the latent image formation start point IMO are controlled with reference to
The TR sensor 60 that generates the noise is low in accuracy, and a 1: 6 gear is interposed between the TR motor 22 and the transfer drum 6. Therefore, even if the gear shifts by one tooth, the transfer start point PO and the latent image formation start point IMO will shift.

Therefore, in this embodiment, as shown in FIG. 11, the signal TRA or TR based on the signal TRZ that first appears after the signal TRS is generated.
B is counted, and it is determined that the time when the count value reaches the value corresponding to the regular transfer point PO is the transfer point PO, and the transfer start position is controlled.

As a result, the latent image formation start point IMO and the transfer start point coincide with each other with high accuracy.

(5) Acceleration / deceleration control of the transfer drum The gripper 17 of the transfer drum 6 is adjusted so that the leading end position of the transfer paper coincides with the latent image formation start point IMO at the transfer start point PO.
It is necessary to be held and transported by. Therefore, at the start of image scanning, the current position of the gripper 17 is detected, and that position is detected at the transfer point PO at the latent image formation start point IM.
It is necessary to control the rotational speed of the transfer drum 6 so as to match O. Conventionally, the position error of the gripper 17 is detected at the image scanning start timing, and the acceleration / deceleration control of the transfer drum 6 is immediately executed based on this position error. However, in this case, since the rotational speed of the transfer drum 6 changes immediately before the gripping operation of the transfer paper,
There was a problem of causing mis-grip.

Therefore, in the present embodiment, as described with reference to FIG. 6, after the gripper position error is detected at the scanning start timing, the acceleration / deceleration control of the transfer drum 6 is started from tP time after the time when the grip operation is actually ended. Is executed, and the process is completed before the transfer point PO is reached. This is achieved by providing a soft timer inside the servo controller 23 for measuring the tP time.

As a result, the acceleration / deceleration control of the transfer drum can be performed without misgripping.

(6) Abnormality Countermeasure As described above, in the present embodiment, the photosensitive drum 1, the transfer drum 6 and the moving optical system are controlled by independent motors and their servo loops. It is necessary to control the position to adjust the position to the normal position. However, this position control is executed based on pulse signals (PRZ, TRZ, etc.) synchronized with the rotation of each motor. Therefore, if an abnormality occurs in these pulse signals or their signal paths, not only positioning becomes impossible, but also the motor remains in an accelerated state even after passing the specified position. It may lead to serious accidents such as burning.

Causes of abnormality in the pulse signal system of the PR drum and the TR drum include those shown in the abnormal state system diagrams of FIGS. 12 to 13.

That is, regarding the system of the PR drum 1, as shown in FIGS. 12 (a) and 12 (b), poor resolution of the rotary encoder,
The number of pulses per rotation of the signals PRA, PRB, and PRZ per drum rotation increases due to a failure of the PR motor 21, a rise in the DC power supply voltage LV, a failure of the synchronous servo circuit 31, or an abnormal input voltage to the optical sensor of the rotary encoder. Poor connection, PR motor
Mechanical overload, synchronous servo circuit for 21 rotating mechanical systems
There is an abnormal phenomenon that the number of pulses per drum rotation decreases due to 31 failures.

The TR drum 6 system is also shown in Fig. 13 (a)-
As shown in (c), the drum 1 of the signals TRA, TRB, and TRZ is caused by defective resolution of the rotary encoder, defective TR motor 22, rise of DC power supply voltage, failure of the synchronous servo circuit 32, and the like.
Abnormality in which the number of pulses per drum decreases due to an increase in the number of pulses per rotation, mechanical overload on the TR motor 22, failure of the synchronous servo circuit 32, abnormal voltage of the optical sensor of the rotary encoder, connection failure, etc. There is a phenomenon. Further, when the moving optical system is stopped at the position of “C−N _S = N _D ” in FIG. 7, the moving optical system may stop at a position that is abnormally close to the stopper side after passing the position of N _S due to noise mixing. Or, a situation may occur in which the motor collides with the stopper and the electric motor as a power source is controlled to be in an accelerated state thereafter, which may cause burnout of the motor winding or burnout of its drive circuit.

Therefore, in this embodiment, if the following situation occurs,
It is determined that there is an abnormal situation, the copying operation is immediately stopped, and a display corresponding to the content of the abnormality is displayed on the display (not shown) of the operation panel (for example, U-1 shown in FIGS. 12 and 13).
U-2, U-3) are performed. As a result, when an abnormality has occurred, it is possible to easily infer what causes the abnormality, and it is possible to take appropriate measures against this.

(6-1) When the photosensitive drum 1 or the transfer drum 6 does not stop even at the end of the copying cycle (a) Normal copying cycle As shown in FIG. 14 (a), the CRG motor 18 moves the moving optical system. Time until the PR motor 21 and TR motor 22 stop with the signal PRZ generated at the timing t1 immediately before switching to the rotation direction to return to the home position as the timing start point
te is measured based on a clock signal of a predetermined frequency, and if te is 17.2 seconds or longer, a signal for position control
It is determined that an abnormality has occurred in PRZ, PRA, TRZ, TRA, etc., and these motors 21, 22 are forcibly stopped, and the copying operation thereafter is stopped.

This abnormality detection processing is performed every time a series of copying cycles is completed.

(B) Positioning operation When the diagnostic mode is set by the maintenance personnel and the origin alignment command is input by one reciprocating motion of the moving optical system by the CRG motor 18, as shown in Fig. 14 (b), or a series of copying. If the PR motor 21 and TR motor 22 do not stop even after the Te time (about 9 seconds) has elapsed from the scan start sensor t1 even when the moving optical system returns to the home position during the origin adjustment before the cycle, Similarly, it is determined that an abnormal situation has occurred, and the copying operation thereafter is stopped.

(6-2) Abnormal cycle of the signal PRZ The signal PRZ is important for accurately adjusting the latent image formation starting point IMO. Therefore, as shown in FIG. 15, one cycle of length T _B of the signal PRZ after activation of the PR motor 21 is measured based on the clock signal of a predetermined frequency, if not within the range between the upper limit value and the lower limit value It is determined to be abnormal, and the subsequent copying operation is stopped.

In this case, as shown in the time chart of FIG. 16, the origin position alignment control of the photosensitive drum 1 and the copy cycle 6 is performed immediately before the three-color copy cycle. The signal PRZ that appears first in this origin position alignment control is shorter than the cycle of the signal PRZ that appears after the timing from the start timing of the PR motor 21. Therefore, this first signal PRZ
Is judged to be abnormal only when it exceeds the upper limit.

FIG. 17 (a) shows C for detecting the period abnormality of this signal PRZ.
The process of PU334 is shown with the flowchart. The "mode 0" in the first step indicates that the mode is when the speed of the PR motor 21 is zero as shown in FIG. 7B, and the process of this flowchart indicates that the PR motor 21 is in the rotating state. Only at the time of "mode 1", the lower limit value <T
If there is no relation of _B <upper limit value, PWM in the synchronous servo circuit 31
The chopper gate-off signal is issued, the rotation of the PR motor 21 is immediately stopped, and abnormality information indicating that an abnormality has occurred in the signal PRZ is transmitted to the master controller 24.

(6-3) Abnormal synchronization between TRS and TRZ The signals TRS and TRZ are important for accurately aligning the latent image formation start point IMO and the transfer point PO. Abnormalities in these signals occur due to abnormalities in the encoder and excess / shortage of motor voltage.

Therefore, as shown in FIG. 18, the signal TRS once rises and then falls, and the time interval T _C1 with the signal TRZ that appears first immediately after this is measured based on the clock signal of a predetermined frequency, and the upper limit value is obtained. If it is out of the range between the lower limit value and the lower limit value, it is determined that the synchronizing relationship between the signals TRS and TRZ is not a normal relationship, and the copying operation thereafter is stopped.

Signal TRZ until a new signal TRS appears normally after T _c1
The time interval T _C2 is measured by the clock signal, and if it is not within the range between the upper limit value and the lower limit value, it is determined to be abnormal.

FIG. 19 is a flowchart showing the process of the CPU 334 for detecting such an abnormal state. The "mold 0" in the first step indicates that the speed of the TR motor 22 is zero, and the processing of this flowchart is executed only in the "mode 1" when the TR motor 22 is in the rotating state. TC1, TC2
In the abnormal expression, the gate off signal of the PWM chopper in the synchronous servo circuit 32 is issued to immediately stop the rotation of the TR motor 22, and the information of the abnormal synchronization of the signals TRS and TRZ is transmitted to the master controller 24.

(6-4) Locking the TR motor The above-mentioned CRG motor 18, PR motor 21, and TR motor 22 are applied with their motor currents adjusted by the synchronization compensator 230 provided in the servo controller 23 as shown in FIG. The deceleration is controlled. That is, when the command pulse train from the control circuit 33 corresponding to the target value of the rotation speed is input, the up / down counter 231 counts up / down the command pulse train. When the count value of the counter 231 increases, the output voltage of the DA converter 232 that converts the count value of the counter 231 into an analog voltage also increases. Since the output voltage of the DA converter 232 is applied to the TR motor 22, for example, via the amplifier 233, the TR motor 22 is activated and sequentially accelerated. TR motor
When the 22 starts up, the pulse generator 22 connected to its rotary axis
From which the signal TRA (or TRB) is generated. Since this signal TRA is input to the down-count input of the counter 231, the count value of the counter 231 becomes zero and the TR motor 22 stops when the rotation amount of the TR motor 22 reaches the rotation amount corresponding to the command pulse train.

In the servo controller 23, the rotation of each motor is made to reach the target value by such a synchronization compensator. However, the transfer drum 6 is provided with a gripper 17 for gripping the transfer paper on its peripheral surface, and the transfer is completed. A release cam (not shown) for peeling off the transfer paper is arranged so as to face the peripheral surface. Therefore, if the gripper 17 and the release cam mesh with each other or the gripper 17 meshes with another protrusion of the frame for some reason, the rotation of the TR motor 22 is locked. Then, since the signal TRA or TRB is not output, the count value of the up-down counter 231 does not decrease at all, the applied voltage of the TR motor 22 remains in the accelerated state, and an accident such as burnout of the winding or the drive circuit is caused. cause.

Therefore, in the present embodiment, as shown in the flowchart of FIG. 21, when the next command pulse train is input to the counter 231 while the TR motor 22 is mechanically locked, the counter 231 immediately overflows is used, When an overflow output occurs, the voltage to the TR motor 22 is immediately cut off and the subsequent copying operation is stopped.

This makes it possible to prevent accidents such as burning of the TR motor 22 and its drive circuit.

(7) Abnormal stop position of moving optical system As described above, the moving optical system is changed to "C-N _S =" in FIG.
When stopping at the position of the N _D ", past the position of the N _S collide or stopped at a position abnormally close to the stopper side, or the stopper by mixing of noise, even after motor acceleration as a power source There is a risk that the motor may be controlled to be in a state, and the motor winding may be burned or its drive circuit may be burned.

Therefore, in this embodiment, after the REG sensor 29 is actuated, the distance to the stop position of the moving optical system is set to the pulse signals CRA and C.
The CPU 334 of the control circuit 33 is provided with a measuring unit that measures by counting RB. Therefore, the measuring means has a phase difference of 90 degrees between the pulse signals CRA and CRB, so the moving direction of the moving optical system is determined depending on which phase is advanced, and if it is moving toward the stop position. ,
The pulse signal CRA or CRB is counted with the operation timing of the REG sensor 29 as the measurement start point, and the distance to the stop position is measured. Then, the measured value is stored until the next measuring time.

The CPU 334 reads the measured value of the measuring means at the time when the power of the copying machine is turned on, immediately before the start of copying the first sheet, or immediately before moving to a series of copying cycles, and compares it with a predetermined value.

For example, an actuator 90 that supports the moving optical systems 10 and 11.
The distance B between the stopper 91 and the stopper 91 is designed so that, for example, B = 5 mm at the regular stop position as shown in FIG. 22, and when the actuator 90 returns from the scan end position to the stop position, the REG sensor after operation 29, it stops at the advanced distance N _S, the position control of the movable optical system 10, 11 by CPU334 such that B = 5 mm is carried out.

However, if an error in reading the pulse signal CRA or CRB or noise occurs, it will pass the normal stop position and the stopper
A situation occurs in which the CRG motor 18 is still under acceleration control in the state of collision with 91. Therefore, the CPU 334 reads the measured value θi of the measuring means immediately before a series of copying cycles, and the absolute value of the difference from the position θS of the stopper 91 | θi−θs | −, for example,
If it is 3.5mm or more or less, it is compared and if it is 3.5mm or less, it is determined that an abnormality has occurred in the pulse signal CRA, CRB generating mechanism or the reading mechanism, and the subsequent copying operation is stopped. At the same time, an abnormality is displayed to inform the maintenance staff of this.

As a result, serious accidents such as burnout of the motor winding and its drive circuit are prevented. This measurement is performed at predetermined time intervals, such as when the power of the copying machine is turned on, immediately before the start of copying the first sheet, or immediately before shifting to a series of copying cycles.

(8) Copy Mode and Diagnostic Mode The servo controller 23 executes the alignment control and abnormality processing described above.

Therefore, if an abnormality occurs in any of the servo loops for a total of three motors, its diagnosis becomes difficult. Therefore, in this embodiment, the master controller 24 is provided with a diagnostic mode and a copy mode, and when the diagnostic mode is selected and a diagnostic command is given, the servo controller 23 is caused to execute the operation corresponding to the command, and the result is displayed. It is possible to diagnose.

FIG. 23 is a state transition diagram showing the transition of the operating state of the present embodiment, and the right side of the figure after the initialization state shows the copy mode and the left side shows the diagnostic mode state transition.

In the copying mode, the fixing device is in a ready state until the temperature of the fixing device reaches a predetermined temperature or the like, but when the ready state ends, cleaning of the photosensitive drum and system initialization are performed. After that, the status of each serve loop is read into the master controller 24 through the serial data line 25, and if the status is normal, the system is ready, and the copy start command is input to sequentially execute the copy cycle for each color. When the copying operation for all colors is completed, the cycle ends and the system returns to the system ready state. However, if there is an abnormality in any of the servo loops, the abnormality detection signal causes an abnormal stop state.

On the other hand, in the diagnostic mode, waiting for a diagnostic command,
When a diagnostic command for alignment of the CRG motor 18, PR motor 21, TR motor 22 and the moving optical system is input, the alignment operation is executed based on the input diagnostic command. Also,
When a diagnostic command for a pulse generator or sensor such as a rotary encoder is input, rotate the corresponding motor,
The servo controller 23 is made to diagnose whether the signal of the pulse generator or the like coupled thereto is correct, and the resulting information is returned to the controller 24.

For example, in the P1 mode for diagnosing the input / output signals with the pulse generator of each drum, the moving optical system and the PR drum 1,
The TR drum 6 is rotated to detect the rising or falling timing of the output signals SNSR and PRZ of the REG sensor 29 and the output sensor TRS of the TR sensor 60, and the detection information is returned to the master controller 24 at that time. Also, moving optics, PR
Positioning operation of the moving optical system in P2 and P4 modes for diagnosing the rotation state and alignment operation of the drum 1 and TR drum 6 (P
4 mode) until the stop command or emergency stop command is input from the operation panel. The PR drum 1 and TR drum 6 are executed until a stop command or an emergency stop command is input from the operation panel.

Therefore, without using a special measuring device, it is possible to perform diagnosis of the entire apparatus and trace a failed portion at the time of occurrence of an abnormality only by inputting a diagnostic command from the operation panel.

The copying machine of this embodiment is capable of copying at a magnifying power by making the moving speed of the moving optical system relatively slower than the rotational speeds of the photosensitive drum and the transfer drum, and in the opposite case, the reducing magnification. Can be copied.

As described above, according to the present invention, the pulse generating means for generating the pulse signal synchronized with the rotation of the transfer means and the timing signal representing the grip timing of the transfer sheet in synchronization with the rotation of the transfer means are provided. A timing pulse generating means for generating and a control means for counting the pulse signal after generation of the timing signal, recognizing a time point when the count value reaches a predetermined value as a reference point up to a transfer start point, and controlling a transfer operation. Since the and are provided, the latent image formation start point and the transfer start point can be matched with each other with high accuracy.

[Brief description of drawings]

FIG. 1 is an overall block diagram showing an embodiment of the present invention.
4 to 4 are detailed configuration diagrams of a pulse generator that generates pulses in synchronization with the rotations of the CRG motor, PR motor, and TR motor, FIG. 5 is a detailed configuration diagram of the servo controller, and FIG. 6 is one copy cycle. 7 is a time chart for explaining the origin alignment control of the moving optical system, FIG. 8 is a time chart for explaining the start alignment control of the photosensitive drum, and FIG. FIG. 9 is a time chart for explaining the start alignment control of the transfer drum, FIG. 10 is a time chart for explaining the start synchronous control of the moving optical system and the photosensitive drum, and FIG. 11 is the transfer start point of the transfer drum. Time chart to explain the control,
Fig. 12 to Fig. 13 are abnormal phenomenon system diagrams showing the abnormal phenomena of the pulse generators of the PR motor system and TR motor system and their causes.
FIG. 14 is a time chart for explaining the abnormality detection operation of the PR motor and the TR motor, FIG. 15 is a time chart for explaining the abnormality detection operation of the signal synchronized with the rotation of the photosensitive drum, and FIG. 16 is a multicolor A time chart for explaining the operation of the entire section of the copying cycle, FIG. 17 is a flow chart for performing the abnormality detection operation of FIG. 15, and FIG. 18 is an explanation of the abnormality detection operation of the signal synchronized with the rotation of the transfer drum. FIG. 19 is a flow chart for carrying out the abnormality detection operation of FIG. 18, FIG. 20 is a circuit diagram showing the configuration of a synchronous compensator of the motor, and FIG. 21 is a mechanical lock of the motor. Time chart for explaining the abnormality detection operation at the
22 is a sectional view showing the positional relationship between the optical scanning mechanism and the stopper, FIG. 23 is a state transition diagram showing the state transition between the copy mode and the diagnostic mode, and FIG. 24 is a schematic configuration diagram showing the configuration of a conventional copying machine. FIG. 25 is a perspective view showing the structure of a movable part position control mechanism in a conventional copying machine. 1 ... Photosensitive drum, 3 ... Charger, 4 ... Exposure part, 5C, 5
Y, 5M …… Developer, 6 …… Transfer drum, 8 …… Original platen, 9 …… Original scanning optical system, 11 to 14 …… Mirror, 15 ……
Color separation filter device, 17 …… gripper, 18 …… CRG motor, 19 …… pulley, 20 …… belt, 21 …… PR motor, 22
...... TR motor, 23 …… Servo controller, 24 …… Master controller, 25 …… Serial data line, 26 to 28
...... Pulse generator, 29 …… REG sensor, 30 to 30 …… Synchronous servo circuit, PO …… Transfer point, IMO …… Latent image formation start point, 6
0 …… TR sensor, 230 …… sync compensator, 231 …… up / down counter, 334 …… microprocessor, 338 …… serial data input / output port.

Front Page Continuation (56) References JP-A-60-121465 (JP, A) JP-A-60-218673 (JP, A) JP-A-54-86344 (JP, A) JP-A-61-158344 (JP , A) JP 61-158345 (JP, A) JP 61-278876 (JP, A) Actual development Sho 60-36651 (JP, U) JP-B 3-65552 (JP, B2) JP-B 4-39670 (JP, B2) JP-B 4-48391 (JP, B2) JP-B 3-30148 (JP, B2)

Claims (1)

[Claims] 1. An optical scanning mechanism for scanning an image surface of a document, a photoconductor that rotates in synchronization with scanning of the optical scanning mechanism, and forms an electrostatic latent image corresponding to the document image; In a control device of a copying machine, which comprises a developing means for developing an electrostatic latent image and a means for transferring the image developed by the developing means onto a recording paper, a pulse for generating a pulse signal synchronized with the rotation of the transferring means. Generating means, a timing pulse generating means for generating a timing signal representing a grip timing of the transfer sheet in synchronization with the rotation of the transfer means, and counting the pulse signal after the generation of the timing signal, and the count value is a predetermined value. The control device of the copying machine is characterized in that the control device controls the transfer operation by recognizing the time point when the transfer start point is reached as a reference point up to the transfer start point.