JP2501844Y2 - Copier control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a control device for a copying machine, which forms an electrostatic latent image on a photoconductor, then develops the phenomenon, and transfers the image to a recording sheet. 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 copied onto 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.

In a multicolor copying machine, an image of an original is color-separated, and the series of steps of charging, exposing, developing, transferring, and cleaning as described above are repeatedly executed for each color separation, and the image of each separated color is the same. By forming the image on the recording paper in an overlapping manner, the same multicolored print as the image of the original is obtained.

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, a document table 102 is provided on the upper surface of the main body 101, and a scan unit 103 is provided below the document 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, and the like, and the lamp 104 and the first mirror 105 are integrated.
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 yellow color,
Further, since the photosensitive drum 111 is charged in advance by the charger 112, the optical image is an electrostatic latent image corresponding to the yellow color of the original on the surface of the photosensitive drum 111. Then, 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 transfer completed portion.

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, a pulley 142 is axially supported by the shaft 132 via a bearing 141. A movable pawl (not shown) driven by a solenoid or the like is provided on the pulley 142 side, and when the pawl is driven to engage a pin 143 provided on the sprocket 133, the rotation of the shaft 132 causes the pulley 142 to rotate. Is transmitted to the photosensitive drum.
It is designed to rotate synchronously in a predetermined relationship with 111. 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 configuration described above, 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 is constant, and the photosensitive drum 111 is also fixed. Since the transfer drum 115 and the transfer drum 115 rotate in opposite directions synchronously, 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. Allows color copying by multicolor 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. There is a drawback that the color shifts to cause color shift.

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.

With such a device, it is possible to reliably prevent the occurrence of color misregistration, and since the scanning unit, the photosensitive drum, and the transfer drum are interlocked by electrical timing, there is no secular change in the positional relationship between them, and it is complicated. There is an advantage that the original can be easily reduced / enlarged and copied without requiring any special mechanical mechanism, and the copy efficiency can be improved by adopting the short scan or the like.

[Problems to be Solved by the Invention] However, in the above-described conventional configuration, the transfer drum is rotated so that the transfer drum acceleration / deceleration control is performed and the leading edge of the transfer paper and the electrostatic latent image formation start point coincide with each other. Since acceleration / deceleration control is performed, if an error occurs in the rotary encoder, the transfer start point and the latent image formation start point shift, and the positional relationship with the document image shifts. Since a color shift occurs due to the formation of a latent electric image, it is no longer possible to obtain a copy image that is faithful to the original image, and the electric motor, which is the power source of the transfer drum, is controlled to be in an accelerated state even when the transfer cycle ends. However, there is a problem in that an accident such as a burnout of the motor winding or its drive circuit occurs, which makes maintenance work thereafter extremely difficult.

The present invention has been made in view of such circumstances, and an object thereof is to provide a copying machine control device capable of obtaining a copied image faithful to an original image and preventing accidents such as burnout of an electric motor. Especially.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an optical scanning system (9) for scanning an original image, and the optical scanning system which rotates in synchronization with the scanning of the optical scanning system. A photosensitive drum (1) for forming an electrostatic latent image corresponding to, developing means (5C, 5Y, 5M) for developing an electrostatic latent image on the photosensitive drum, and rotating in synchronization with the photosensitive drum, A transfer drum drive motor (22) for driving the transfer drum, and a transfer drum drive in a control device of a copying machine, comprising a transfer drum (6) for transferring a developed image developed by the developing means onto a recording sheet. Reference signal generating means (28) arranged on the rotation shaft of the motor and generating a reference signal indicating the reference position of rotation of the transfer drum drive motor (28).
A), and pulse generating means (60) arranged at the grip position of the recording paper of the transfer drum and generating a pulse signal indicating the grip timing of the recording paper by the transfer drum,
Pulse signal (TRS) generated from the pulse generating means
And a reference signal (TP
Z) and a control means (2) for measuring the time interval and determining whether or not the measured time interval is within a specified range and stopping the copying operation of the copying machine if the measured time interval is not within the specified range.
3) and are provided.

[Operation] While measuring the time interval between the pulse signal generated from the pulse generating means and indicating the grip timing of the recording paper and the reference signal indicating the reference position of the rotation of the transfer drum drive motor generated from the reference signal generating means, Since the control means for determining whether or not the measurement time interval is within the specified range and stopping the copying operation of the copying machine when the measured time interval is not within the specified range is provided, the synchronous relationship between the transfer drum drive motor and the transfer drum is maintained. When the condition is out of the normal state, the copying operation of the copying machine is immediately stopped automatically, which can prevent accidents such as burning of the transfer drum drive motor.

[Embodiment] Hereinafter, the present invention will be described in detail based on an embodiment.

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, and serves as an exposure light source at the same speed as the peripheral speed V of the photosensitive drum 1 below the original placing table 8 from the left side of the table to the right side of the table along the lower surface. The first moving mirror 11 that reciprocates together with the document illumination lamp 10 to scan the downward document surface on the table 8 through the table 8 and the peripheral speed of the photosensitive drum 1
Second and third mirrors 12, 13 reciprocating at 1/2 speed,
When a print start button (not shown) is pressed, the movable optical systems 10 and 11 reciprocate to scan the original image sequentially through the table 8 from left to right. L is the first mirror 11 → the second mirror 12 → the third mirror 13 →
Images are sequentially formed on the path of the fourth 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. Let me
By rotating the rotating shaft by 90 degrees, each filter is positioned in the optical path of the scanning light L. Further, the filter device 15 and the color developing devices 5Y, 5M, 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 In the case of 15G, 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 tram 1, and the transfer paper sent from the paper supply unit (not shown) to the drum 6 is grippered. It is held by 17, 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, charging, exposure, development, and development are performed for each color separation image of the document.
A series of image forming processes of transfer and cleaning are repeatedly executed to produce a color print.

In this case, the image formation process for the first color separation image is started by the print start button, but for the second and third colors, the print restart signal is sent to the internal circuit when the previous process is completed. When generated, the image forming process is started.

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 surface of the photosensitive drum as a yellow toner image having a complementary color relationship with blue.
The yellow toner image is transferred onto the surface of the transfer paper 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. The magenta toner image is formed on the tram surface, the yellow toner image is first transferred to the magenta toner image, and subsequently, the magenta toner image is superposed and transferred onto the transfer paper surface wound around the drum 6.

During 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 of the original image is a cyan toner image complementary to 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 paper 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 printouts are output from the output tray.

The moving optical system, the photosensitive drum 1 and the transfer drum 6 described above are given power for movement or rotation by independent motors. That is, the moving optical system 10, 11
The power source of is supplied by a motor 18 (hereinafter referred to as a CRG motor 18) via a pulley 19 and a wire 20. 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). And these CR
The G motor 18, the PR motor 21, and the TR motor 22 are controlled by the servo controller 23. The servo controller 23 is further controlled by a master controller 24 as its upper control means. The master controller 24 receives signals 1MS and PRZ signals described later from the servo controller 23, and controls the entire copy cycle and executes abnormality diagnosis processing.
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 CRG motor 18 includes a rotary encoder 26A for generating a rotation pulse signal CRZ indicating that the motor 18 has made one rotation, and a CRZ.
The rotary encoder 26B that generates one pulse signal CRB for each predetermined rotation angle of the motor 18 and the phase of the signal CRB
A pulse generator 26 including a rotary encoder 26C that generates pulse signals CRA different by 90 degrees 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 rotated once, and a predetermined rotation of the PR motor 21. A rotary encoder 27B that generates one pulse signal PRB for each angle, and a rotary encoder 27C that generates a pulse signal PRA whose phase is 90 degrees different from the signal PRB.
A pulse generator 27 consisting of and 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. Further, IMO is the starting point of the electrostatic latent image formation and is located at a position deviated from PRO by α degrees.

Further, as shown in detail in FIG. 4, the rotation shaft of the TR motor 22 is one per rotation of the motor 22 (however, since there is a speed reduction mechanism between the TR motor 22 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, a rotary encoder 28B that generates one pulse signal TRB for each predetermined rotation angle of the TR motor 22, and the above signals. A pulse generator 28 including a TRB and a rotary encoder 28C that generates a pulse signal TRB having a phase difference of 90 degrees is attached. Further TR motor
The transfer drum 6 driven by 22 is provided with an actuator 6A projecting at a portion corresponding to the position of the gripper 17 on the inner peripheral surface thereof, and the sensor 6B fixed to the frame is actuated so that the transfer paper grip timing It is configured to take out the signal TRS.

In the following, the pulse generator including the actuator 6A and the sensor 6B is referred to as a TR sensor 60.

The servo controller 23 outputs the output signal TR of this TR sensor 60.
By counting the output signal of the encoder 28B or 28C with S as the reference, the grip timing of the transfer paper is predicted, and the time until the grip position at the predicted timing actually reaches the transfer start point PO (distance or The position) is calculated, and the speed of the TR motor 22 is accelerated or decelerated so that the latent image formation start point IMO and the transfer start point PO coincide with each other.

In FIG. 1, a switch 29 provided at a position separated from the home position of the moving optical systems 10 and 11 in the operation direction by a predetermined distance detects a scanning start timing of an image. Hereinafter, the operation timing of the 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 a CRG motor 18, a PR motor 21, and a T motor.
It is composed of three systems of synchronous servo circuits 30, 31, 32 for independently controlling the rotation state of the R motor 22 to a target rotation state, and a control circuit 33 for controlling these in a predetermined synchronization relationship.

Each of the synchronous servo circuits 30 to 32 will be described as a representative of the synchronous servo circuit 30 of the CRG motor 18.
OR gates 301 and 302, FV converter 303, sync compensator 304, F
It is composed of a V converter 305, an error amplifier 306, a direction discriminator 307, an overcurrent detector 308, and a PWM chipper 309, and its control circuit input is output from the speed command generator 330 of the control circuit 33. Speed command pulse SCP composed of A-phase and B-phase signals whose phase difference differs by 90 degrees, and position pulse PCP composed of UP signal and DOWN signal output from position command generator 331 of control circuit 33. , A gate-off pulse GOFF for shutting off the output gate of the PWM checker 309 is input. As the output to the control circuit side, the overcurrent detection signal of the overcurrent detector 309 and the rotation direction of the CRG motor 18 detected by the direction discriminator 307 are either the forward rotation (UP) or the reverse rotation (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,
The CRZ is 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 transmitted via the OR gate 333 of the control circuit 33 to the microprocessor (CP
U) 334 interrupt signal is input, and if an overcurrent flows in the CRG motor 18, the CPU 334 interrupt process
Emergency stop control of the G motor 18 is performed. 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
Only (P) is input from the speed command generator. As for the TR motor 22, since the acceleration / deceleration control of the TR motor 22 needs to be performed in order to make the transfer start point coincide with the latent image formation start point as described later, the speed command pulse SCP
(T) and position command pulse PCP (T) are used for acceleration / deceleration command generator 3
It is input from 36.

In addition, the TR motor 22
The rotation direction detection signals RPU, PPD and the output signal TRZ of the pulse generator 28A are input to the transfer drum rotation angle detector 337, and the current rotation angle of the TR drum 6 is detected by these signals. 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, an operation that includes a switch for setting a known copy mode such as the number of copies, paper size, reduction / enlargement ratio, etc., a copy start switch, an error display lamp, a switch for setting a diagnostic command for maintenance and inspection, etc. Since the panel is connected to the master controller 24, these various types of switch information are sent to the master controller 2 via the serial data input / output port 338.
It is designed to send and receive to and from 4.

Here, the operation of the cyclic servo circuit of the CRG motor 18 will be described as a representative as follows.

First, if only the speed command pulse SCP (C) is input without giving the position command pulse PCP (C), the pulse SCP
Direction discriminator 300 based on the phase difference between A phase and 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 fed through the OR gate 301 to the synchronization compensator.
It is input to the FV converter 303 while being input to 304. 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, the 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 309 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. As a result, 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. Therefore, in the synchronization compensator 304, the count value gradually decreases as the CRG motor 18 rotates, but the analog conversion voltage of the count value is input to the error amplifier 306 as a synchronization error signal.
The output current of the WM chipper 309 is also changed by this synchronization error signal. 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,
Phase of the pulse PCP (C) and output pulse of the direction discriminator 307
An error voltage corresponding to the deviation from the phase of RPU or RPD is output from the synchronization compensator 304, and by varying the output current to the CRG motor 18 so that the error voltage becomes zero,
The position of the moving optical system is controlled to the target position.

In the above-mentioned configuration, a series of copying cycles of the following steps are executed. That is, Fig. 6 shows CRG
Rotation angles of motor 18, PR motor 21, and TR motor 22 θCRG, θ
It is a time chart showing PR, θTR and their synchronization relationship,
The horizontal axis represents time and the vertical axis represents the 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, when the moving optical system reaches the position of the REG sensor 29 and the scanning start timing signal SNSR is output from the sensor 29,
An electrostatic latent image is sequentially formed from the electrostatic latent image formation start position IMO of the photosensitive drum 1 which is defined by the generation timing of this signal. On the other hand, the TR motor 22, which is the power source of the transfer drum 6,
Although it is started almost at the same time as the PR motor 21, at the timing T when the signal SNSR is output, the time until the grip timing signal TRS of the transfer paper is generated is predicted and calculated, and the transfer drum is judged from the predicted value. 6 rotation speed VP
If R is a velocity at which the latent image formation start point IMO and the transfer point PO coincide, as shown by the velocity change line i. It 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. After tp time, the control for reducing the speed of the motor 22 is started. On the contrary, as indicated by the speed change line ii, the signal TR
When the time to S is longer than the normal value, the acceleration control of the TR motor 22 is started after tp 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 multicolor print without color misregistration, in addition to the position control of the transfer start point by the acceleration / deceleration control of the TR motor 22 as described above, the synchronous control of the PR motor 21 and the CRG motor 18 is performed. Position control for the moving optical system to start from the regular home position, PR motor 21 and TR motor for matching the latent image formation start point IMO and the scan start timing
It is necessary to control the starting position of 22 and further control when an abnormality occurs such as when the signals PRZ and TRZ are not output.

 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, a 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 provided inside the servo controller 23. Has been. 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, the output signal SNSR of the REG sensor 29 that is operated when the moving optical systems 10 and 11 are moved in the scanning direction of the original image at any of the above-mentioned timings and the optical system returns to the stop position.
As a reference, the time ND from the reference timing to the generation timing of the reference signal CRZ is measured with reference to the generation timing of the reference signal CRZ.

Then, when the optical systems 10 and 11 return to the stop position, the time when NS = C−ND ... (1) is generated after the reference signal CRZ is generated is measured by the rotation pulse CRA or CRB,
The CRG motor 18 is stopped in NS time after the signal CRZ is generated.

As a result, the position where the REG sensor 29 operates and the optical system 1
The distance from the stop position of 0 and 11 is always controlled so that NS + ND = 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 activated before the start and end of a series of copying cycles, and the signal PR
The signal PRA (or PRB) and the signal TRA (or TRB) are counted with Z and TRS respectively as the reference, 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 By stopping the TR 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 with the signal PRZ as a reference, and the PR motor 21 is stopped when the count value reaches a predetermined value NstP. Let the TR motor 22
About the signal 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 TRS, and the gripper 17
After reaching the count value NPO that passes through the transfer point PO, the TR motor 22 is controlled to stop when it reaches the count value “NPO + NSTP”, which is the count value NSTP when the PR motor 21 is stopped. There is.

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 or 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 by using the start timing of the moving optical system as a starting point, and when the measured time reaches the next copying start time, the moving optical system is restarted to form an electrostatic latent image of the next color. However, in this case, the synchronous relationship between the moving optical system and the photosensitive drum 1 is deviated for each color copying cycle due to the uneven rotation cycle of the photosensitive drum 1 and the accuracy of the soft timer for the clock. However, there has been a problem that the deviation is accumulated and the density unevenness for each color is further increased.

Therefore, in this embodiment, a counter that counts the signal PRA or PRB with the signal PRZ as the reference angle is provided inside the servo controller 23, and as shown in the time chart of FIG. 10, the exposure value indicated by the count value of this counter is set. The moving optical system is activated each time the rotation angle θB of the drum 1 reaches the constant rotation angle L1.

With this arrangement, even if the rotation period of the photosensitive drum 1 becomes uneven, as long as the position where the signal PRZ is generated and the latent image formation start point IMO are held in a relationship of α degrees as shown in FIG. ,
The synchronous relationship between the moving optical system and the photosensitive drum 1 is always kept constant, and a copied 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 signal SN of the REG sensor 29.
Acceleration / deceleration control is performed so that the transfer start point PO and the latent image formation start point IMO match with SR as a reference.
The TR sensor 60 that generates S has low accuracy and the TR motor 22
There is a 1: 6 gear between the transfer drum 6 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.
Signal TRA or the signal TRZ that first appears after the occurrence of
TRB is counted, 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 1 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 7. Therefore, at the start of image scanning, the developing 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 and the transfer drum 6 are used.
Since the moving optical system and the moving optical system are controlled by independent motors and their servo loops, it is necessary to perform position control for matching the respective relationships to normal positions before the start of the copying cycle. 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 the abnormalities of the pulse signals of the PR drum and the TR drum include those shown in the abnormal state system diagrams of FIGS. 12 to 13.

That is, the PR drum 1 system is shown in FIG.
As shown in (b) and (b), the number of pulses per rotation of the drum of the signals PRA, PRB, PRZ is reduced due to poor resolution of the rotary encoder, PR motor 21, defective DC power supply voltage LV, failure of the synchronous servo circuit 31, etc. Abnormal phenomenon in which the number of pulses per drum rotation decreases due to an increase in input voltage, abnormal input voltage to the optical sensor of the rotary encoder, poor connection, mechanical overload to the PR motor 21 rotation mechanism system, or failure of the synchronous servo circuit 31. There is.

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. In addition, when the moving optical system is stopped at the position of "C-NS = ND" in FIG. 7, it is stopped at a position that is abnormally close to the stopper side after passing the position of NS due to the mixing of noise,
Alternatively, 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 result in burnout of the motor winding or burnout of its drive circuit.

Therefore, in the present embodiment, if the following situation occurs, it is determined that an abnormal situation has occurred, the copying operation is immediately stopped, and a display (not shown) on the operation panel displays a message corresponding to the content of the abnormality ( For example, U- shown in FIG. 12 and FIG.
1, U-2, U-3). With this, when an abnormality occurs, it is possible to easily infer what causes the abnormality, and it is possible to appropriately deal with 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. Measure the time te until the PR motor 21 and TR motor 22 stop, based on the clock signal of the specified frequency, 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
If it is, for example, 17.2 seconds or more, it is determined that an error has occurred in the signals PRZ, PRA, TRZ, TRA for position control,
These motors 21 and 22 are forcibly stopped and the subsequent copying operation is stopped.

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

(B) During positioning operation The diagnostic mode is set by maintenance personnel, and Fig. 14 (b)
Even if the moving optical system returns to the home position when the origin alignment command is input by one reciprocating movement of the moving optical system by the CRG motor 18 or when the origin is aligned before a series of copying cycles as shown in, the PR motor If the TR motor 22 does not stop even after the elapse of Te time (about 9 seconds) from the scan start timing t1 or more, it is determined that an abnormal situation has occurred as described above, and the subsequent copying operation 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, after the PR motor 21 is started, the length TB of one cycle of the signal PRZ is measured based on the clock signal of the predetermined frequency, and if it is not within the range of the upper limit value and the lower limit value, it is abnormal. Then, the subsequent copying operation is stopped.

In this case, as shown in the time chart of FIG.
Immediately before the color copying cycle, the origin alignment control of the photosensitive drum 1 and the transfer drum 6 is performed in advance. 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) is a flowchart showing the processing of the CPU 334 for detecting the cycle abnormality of the signal PRZ. In addition,
“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 is performed when the PR motor 21 is in the rotating state. It is executed only in "Mode 1" of and the lower limit value <TB
<If there is no relation of the upper limit value, the gate off signal of the PWM chopper in the synchronous servo circuit 31 is issued, the rotation of the PR motor 21 is immediately stopped, and the error information indicating that the signal PRZ is abnormal is output to the master controller 24 Sent to.

(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 immediately after this, the time interval TC1 with the signal TRZ that first appears is measured based on the clock signal of a predetermined frequency, and the upper limit value is set. If it is outside the range of the lower limit value, it is determined that the synchronizing relationship between the signals TRS and TRZ is not a normal relationship, and the subsequent copying operation is stopped.

Similarly, the signal until a new signal TRS appears after Tc1
TRZ time interval TC2 is measured by the previous period clock signal,
If it is not within the range between the upper limit value and the lower limit value, it is determined as abnormal.

FIG. 19 is a flowchart showing the process of the CPU 334 for detecting such an abnormal state. The "mode 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
Is abnormal, a gate-off signal of the PWZM chopper in the synchronous servo circuit 32 is issued to immediately stop the rotation of the TR motor 22, and information on 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 corresponding to the target value of the rotation speed is input from the control circuit 33, the up / down counter 231 counts up the command pulse train. When the count value of the counter 231 increases, the DA converter 2 that converts the count value of the counter 231 into an analog voltage
The output voltage of 32 also rises. Since the output voltage of the DA converter 232 is applied to, for example, the TR motor 22 via the amplifier 233, T
The R motor 22 is activated and sequentially accelerated. When the TR motor 22 is activated, the signal TRA (or TRB) will be generated from the pulse generator 22 coupled to its rotating shaft. This signal
Since TRA is input to the down count input of the counter 231, when the rotation amount of the TR motor 22 reaches the rotation amount corresponding to the command pulse train, the count value of the counter 231 becomes zero and T
The R motor 22 stops.

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 with the TR motor 22 mechanically locked, the counter 231
Is used to immediately shut off the voltage to the TR motor 22 and stop the subsequent copying operation when an overflow output occurs.

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

(7) Abnormal stop position of the moving optical system As described above, the moving optical system is changed to "C-NS = ND" in FIG.
When stopping at the position, the motor stops as a position exceeding the NS position and abnormally approaches the stopper side due to noise mixing, or collides with the stopper, and the electric motor as the power source is still controlled to the acceleration state. This may result in burnout of the motor winding and burnout of its drive circuit.

Therefore, in this embodiment, after the operation of the REG sensor 29,
The CPU 334 of the control circuit 33 is provided with measuring means for measuring the distance to the stop position of the moving optical system by counting the pulse signals CRA and CRB. Therefore, since the measuring means has the pulse signals CRA and CRB and their phases differ by 90 degrees,
The direction of movement 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 time. Then, measure the distance to the stop position. 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 the first copy, or immediately before a series of copying cycles, and compares it with a predetermined value.

For example, an actuator 9 that supports the moving optical systems 10 and 11.
The distance B between 0 and the stopper 91 is the 22nd at the regular stop position.
As shown in the figure, for example, it is designed so that B = 5 mm, and when the actuator 90 returns from the scanning end position to the stop position, after the REG sensor 29 operates, it stops at a distance advanced by NS, and B = The position of the moving optical systems 10 and 11 is controlled by the CPU 334 so that the distance becomes 5 mm.

However, if a reading error or noise of the pulse signal CRA or CRB occurs, the CRG motor 18 is still under acceleration control in a state of passing the regular stop position and colliding with the stopper 91. Therefore, the CPU 334 reads the measured value θi of the measuring means immediately before a series of copying cycles and determines whether or not the absolute value | θi−θs | of the difference from the position θS of the stopper 91 is, for example, 3.5 mm or more or less. If 3.5 mm or more, or less, it is determined that an abnormality has occurred in the pulse signal CRA, CRB generation mechanism or the reading mechanism, and the subsequent copying operation is stopped, and an abnormality is displayed to notify maintenance personnel of this. I do.

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 perform an operation corresponding to the command, and the result is diagnosed. I am making it possible.

FIG. 23 is a state transition diagram showing the transition of the operation state of this embodiment, the right side of the diagram after the initialization state is the copy mode,
The left side shows the state transition of the diagnostic mode.

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 this, the status of each servo loop is read by the master controller 24 through the serial data line 25, and if the status is normal, the system ready status is entered, and the copy start command is input, and the copy cycle for each color is sequentially performed. 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, it waits for a diagnostic command, and when a diagnostic command for alignment of the CRG motor 18, PR motor 21, TR motor 22 and the moving optical system is input, it is based on the input diagnostic command. Position alignment operation. When a diagnostic command for a pulse generator such as a rotary encoder or a sensor is input, the corresponding motor is rotated, and the servo controller 23 is diagnosed as to whether or not the signal of the pulse generator coupled to the motor is correct. Then, the controller 24 is caused to return the resulting information to the controller 24.

For example, in the P1 mode, which diagnoses the input / output signals to / from the pulse generator of each drum, the moving optical system and PR drum
1, TR drum 6 is rotated, REG sensor 29 output signal SNSR
Also, the rising or falling timing of the output signal TRS of the PRZ and TR sensor 60 is detected, and the detection information is returned to the master controller at that time. In addition, in the P2 and P4 modes for diagnosing the rotation state and alignment operation of the moving optical system, PR drum 1 and TR drum 6, the alignment operation of the moving optical system (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.

[Advantages of the Invention] As described above, according to the present invention, an optical scanning system for scanning an original image and an electrostatic latent image corresponding to the original image, which rotates in synchronization with the scanning of the optical scanning system. A photosensitive drum for forming an electrostatic latent image on the photosensitive drum, a developing unit for developing an electrostatic latent image on the photosensitive drum, a transfer drum that rotates in synchronization with the photosensitive drum, and transfers the developed image developed by the developing unit onto recording paper. And a transfer drum drive motor for driving the transfer drum, and a reference position of rotation of the transfer drum drive motor, which is disposed on a rotation shaft of the transfer drum drive motor. A reference signal generating means for generating a reference signal, and a pulse generating means arranged at a grip position of the recording paper of the transfer drum, for generating a pulse signal indicating a grip timing of the recording paper by the transfer drum,
The time interval between the pulse signal generated by the pulse generating means and the reference signal generated by the reference signal generating means is measured, and it is determined whether or not the measured time interval is within a specified range. If it is not within the range, the control means for stopping the copying operation of the copying machine is provided. Therefore, if the synchronous relationship between the transfer drum drive motor and the transfer drum is out of the normal state, the copying operation of the copying machine is immediately started. Since it is automatically stopped, it is possible to prevent accidents such as burnout of the transfer drum drive motor.

[Brief description of drawings]

FIG. 1 is an overall block diagram showing an embodiment of the present invention, and FIG.
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.
14 is a time chart for explaining the abnormality detection operation of the PR motor and 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 all sections 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 control mechanism in a conventional copying machine. 1 ... Photosensitive drum, 3 ... Charger, 4 ... Exposure part, 5C, 5
Y, 5M …… Developer, 6 transfer drums, 8 …… Original platen, 9
...... Document 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, 26-28 ... Pulse generator, 29 ... REG sensor, 30-31 ... Synchronous servo circuit, PO ... Transfer point , IMO ... Latent image formation start point, 60 ... T
R sensor, 230 ... synchronization compensator, 231 ... up-down counter, 334 ... microprocessor, 338 ... serial data input / output port.

Claims (1)

(57) [Scope of utility model registration request] 1. An optical scanning system for scanning an original image; a photosensitive drum which rotates in synchronization with scanning of the optical scanning system to form an electrostatic latent image corresponding to the original image; A control device for a copying machine, comprising: a developing unit that develops an electrostatic latent image; and a transfer drum that rotates in synchronization with the photosensitive drum and that transfers the developed image developed by the developing unit onto a recording sheet. A transfer drum driving motor for driving the transfer drum; reference signal generating means disposed on a rotation shaft of the transfer drum driving motor for generating a reference signal indicating a reference position for rotation of the transfer drum driving motor; A pulse generating unit that is arranged at a grip position of the recording paper on the transfer drum and that generates a pulse signal indicating a grip timing of the recording paper by the transfer drum; The time interval between the reference signal generated by the reference signal generator and the reference signal generated by the reference signal generating means, and whether or not the measured time interval is within a specified range. And a control unit for stopping the copying operation.