JPH0820837B2 - Copy 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 having a belt photoreceptor having a seam.

(Prior Art) Since the belt photosensitive member in this type of copying machine has a seam, the image forming area on the belt is determined so as to be at equal intervals for each size, avoiding the seam of the belt photosensitive member. Therefore, even in a copying machine in which the position of the latent image formed on the photoconductor changes due to zooming, the image forming position must be constant regardless of zooming. For this reason, conventionally, in a copying machine in which the position of the latent image formed on the photoconductor changes due to zooming, it is necessary to change all the application timings of the electrical load required for the formation with the change in the latent image formation position. Was there. Therefore, the control program is complicated and the control efficiency is poor.

(Object) The present invention has been made based on such a background, and has a simple control program and is capable of forming an image by avoiding the seam of the photoconductor belt by position control with good control efficiency. The purpose is to provide.

(Structure) Therefore, the present invention is characterized in that the counting start position of the timing pulse is changed according to the movement of the latent image position.

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a copying machine according to the present invention, which comprises a copying machine main body A and a circulating type document feeder (hereinafter referred to as RDF) B. A copying operation using these will be described.

The copying operation is started by setting the required copying style on the operation unit provided in the main body A of the copying machine and pressing the start button. Here, the copy operation when using RDF will be described.

The RDF has a document tray 201, and a document placed on the document tray 201 is fed by a document feeding belt 202, and is fed onto a contact glass 101 through a document feeding path 203. Then, the original is illuminated by the flash lamp 102 over the entire surface.
The flash lamp power supply 103 is charged in advance by a control device described later and emits light at a predetermined timing.

The reflected light from the original is reflected by the first mirror 104 and the through lens 1
05, the belt photosensitive member 107 is exposed by the second mirror 106.
The photoreceptor 107 is uniformly charged by a charger 108, and forms an electrostatic latent image by exposure. The electrostatic latent image on the photoconductor 107 is erased by the eraser 109 to remove unnecessary charges, developed by the developing device 110, and sent to the transfer unit.
Then, the developed document image is transferred to the transfer paper by the transfer charger 111. This transfer sheet is
The sheet is fed by any one of 3, 114, passes through the conveyance path 115, and is sent to the transfer unit at a timing with the original image by the registration roller 116.

The transfer sheet on which the image is formed passes through the conveyor belt 117 and the fixing device 1
It is fixed by 18, and is transported to the paper discharge toilet 119.

The original on the contact glass 101 is transported by the original transport belt 204.
Is sent out after the light irradiation is completed, and the document discharge roller 206
Is returned to the original tray 201 again. Document discharge roller 2
06 can be rotated in the forward and reverse directions.When the front and back sides of the original are to be the same as in the original state, the original discharge roller 206 is rotated in the reverse direction after the trailing edge of the original has passed through the original switching claw 205, and the original is fed through the forward conveyance path 207. When it is desired to eject the original document and to reverse it, the original document ejection roller 206 is driven as it is and ejected from the reverse conveyance path 208.

Since the belt photoconductor 107 has a seam, the image forming areas on the belt are determined so as to avoid the seam of the belt photoconductor 107 and be evenly spaced for each size.

FIG. 2 is a diagram showing an example of the arrangement of image forming areas (segments) of the belt photosensitive member cut and developed at the seams. In the example of the figure, five A4 segments indicated by the one-dot chain line, four B4 segments indicated by the broken line, and three A3 segments indicated by the two-dot chain line are determined so as to have equal intervals.

FIG. 3 is a control block diagram for forming an image on the belt photoconductor 107, which is shown together with the belt photoconductor 107. Hereinafter, this operation will be described.

As shown above, during image formation, to avoid seams,
Prior to image formation, it is necessary to determine the image forming area on the photoconductor 107. Therefore, a synchronization mark 2 (see FIG. 2) is provided at a fixed distance from the seam 1 (see FIG. 2) on the edge of the belt photosensitive member 107 so that the mark sensor 17 can detect it. To determine the image formation area, the photoconductor 10
It is necessary to drive 7 and detect this mark. Therefore, the drive signal from the output port 13 is input to the motor control circuit 14, and the motor control circuit 14 drives the photoconductor drive motor 15. An encoder 16 is integrally attached to the photoconductor drive motor 15, and outputs a number of pulses proportional to the moving distance of the belt photoconductor 107. The pulse signal is input to the motor control circuit 14 and is used to rotate the photoconductor drive motor 15 at a constant speed. Furthermore, the pulse is input to the frequency dividing circuit 12, and after being divided by a predetermined frequency dividing ratio, the CPU 1
Input to 0 and counted by CPU10. Since this signal is proportional to the amount of movement of the photoconductor 107, the image forming area is determined by this count value.

As an example, the determination of the A4 segment will be specifically described.

The number of pulses in one round of the photoconductor 107 is n ₀ . This is the number of pulses from when the sync mark 2 on the photoconductor is detected by the mark sensor 17 and input as a mark signal to the input port 11 until the next mark signal is detected.

A value obtained by dividing the number of pulses n ₀ by 5 which is the number of A4 segments is the width of the image area of the A4 segment. The pulse value at the beginning of the image area is given by the following equation.

Pulse value at the beginning of A4 segment = a + n x (n _0/5 )
n = 0,1,2,3,4 The latent image forming operation in the next copying operation will be described.

When the head value of the segment reaches a predetermined value, a sequence operation starts, and a counter for sequence control starts operating. This counter performs a count-up operation by the pulse signal from the frequency dividing circuit 12, but it is not cleared by the mark signal, and the count-up operation is performed until the sequence is completed.

The operation will be sequentially described below.

When the counter starts operating and the count value reaches the value of CNT0, the output port 13 outputs a signal to the power pack 18, and the transfer charger 111 and the separation charger 120 start operating. Further, the photoconductor 107 rotates and the count value is CNT.
When the value becomes 1, the charger 108 operates by the same operation as described above to uniformly charge the photoconductor 107. When the count further progresses and the count value becomes CNT2, a charge start signal is input to the flash power supply 103 by the output port 13 and the electric charge is stored in the capacitor in the flash power supply 103 in order to turn on the flash lamp 102. Then, by sending a flash signal to the flash power supply 103, the flash lamp 102 is turned on to illuminate the original set on the contact glass 101, and the reflected light is reflected by the first mirror 104, the through lens 105, and the second mirror 106. Then, the photoconductor 107 is exposed to light. The flash signal at this time is output when the count value is CNT3. In addition, the exposed image area is
The charge of the unnecessary portion is removed by 109, and a latent image is formed.
Shown in the figure.

The solid line shows the same magnification and the dotted line shows the variable magnification. Photoconductor 10
In each case above 7, the leading position of image formation is set to E1,
Shown as E2. In this way, the projection position of the document moves during zooming. However, since the photoconductor 107 has a seam, the position where an image is formed must be constant regardless of the magnification. Therefore, the charging charger for image formation is turned on, the start of document feeding, the start of charging of the flash power source, etc. are compared at the same magnification,
It is necessary to shift the timing corresponding to the distances of E1 and E2, but in order to simplify it, it is sufficient to shift the start position of the sequence operation by the number of pulses corresponding to the distances of E1 and E2.
That is, when the number of pulses corresponding to the movement of the position from the magnification during zooming and [Delta] d, the number of pulses of the start of the A4 segment a + Δd + n × (n 0/5) n = 0,1,2,3, 4, so the start position of the sequence moves by Δd, so
It is not necessary to move at the timing of other electric loads to be moved, and control efficiency is improved.

(Effect) The present invention is as described above, and according to the copy control device of the present invention, the latent image is formed by avoiding the seam of the photoconductor belt without having to move the timing of all electric loads. Therefore, the control efficiency of the copying machine can be remarkably improved.

[Brief description of drawings]

1 is a schematic view of a copying machine to which the present invention is applied, FIG. 2 is a view showing a latent image position on a belt photosensitive member, FIG. 3 is a control block diagram according to an embodiment of the present invention, and FIG. The figure shows the movement of the latent image forming position during zooming.

Continuation of the front page (56) Reference JP 59-140461 (JP, A) JP 54-74749 (JP, A) JP 60-64374 (JP, A) JP 62-184483 (JP , A) JP 59-140466 (JP, A) JP 62-124570 (JP, A) JP 62-124569 (JP, A) JP 60-257439 (JP, A) JP 60-35974 (JP, A) JP-A 60-218670 (JP, A) JP-A 59-75237 (JP, A) JP-A 62-150267 (JP, A) JP-A 54-15751 (JP, A) A) JP 59-111168 (JP, A) JP 59-75237 (JP, A) JP 60-6061 (JP, A) JP 50-152715 (JP, A) JP 60 -230126 (JP, A) Actually opened 60-56054 (JP, U) JP 57-10424 (JP, B2) JP 62-13660 (JP, B2)

Claims (1)

[Claims] 1. A belt-shaped photoreceptor exposed by optical writing means, a plurality of electric loads for forming an image on the exposed belt-shaped photoreceptor, and rotation of the belt-shaped photoreceptor. Timing pulse generating means for generating a series of timing pulses, counting means for counting the timing pulses generated by the timing pulse generating means, and control for controlling the operation of the plurality of electric loads according to the count value by the counting means A copying control device for an electrophotographic copying machine, in which the formation position of the electrostatic latent image formed on the belt-shaped photosensitive member changes by a predetermined amount during zooming. The image forming areas are distributed at equal intervals while avoiding the seams of the belt-shaped photoconductors and correspond to the electrostatic latent image formation position that changes according to the magnification change. It is possible to increase or decrease the number of pulses corresponding to the movement of the image forming start position from the time of equal magnification to the count value of the timing pulse by the counting unit, and control so that the image forming start position written by the writing unit becomes constant. Characteristic copy control device.