JPS63259576A - Color copying machine - Google Patents

Abstract

PURPOSE:To prevent a misalignment generated at the time of synthesizing a color, by providing independently a control means for controlling a position, on a scanning optical system, a photosensitive body and a transfer body being non-driving bodies, respectively. CONSTITUTION:As for a photosensitive body belt 1, a scanning optical system 4 and a transfer belt 9, servo-motors 21-23 being driving sources are provided separately and independently, respectively, encoders 24-26 are provided additionally, the servo-motor 22 is disposed under the control of a motor control board 27, and also, the servo-motor 21 and the servomotor 23 are placed under the control of a motor board 28. Accordingly, the scanning optical system, the photosensitive body and the transfer body being non-driving bodies are controlled separately and independently, respectively, and an exact and arbitrary control operation can be executed. In such a way, the misalignment of the three is prevented completely.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention sequentially performs multiple color separation exposure of a color document on a photoreceptor by repeatedly scanning with a scanning optical system, and converts the latent image formed on the photoreceptor into The present invention relates to a color copying machine in which, after each development is performed with an opposing complementary color toner, the image is repeatedly transferred onto a transfer sheet held by a transfer member that is conveyed in contact with the photoreceptor.

(Prior art) In general, a color copying machine is equipped with a transfer drum or a transfer belt that is placed in opposing contact with a photoreceptor drum, and a scanning optical system that scans the original is placed on the photoreceptor drum to separate and expose the color original in multiple colors. are performed sequentially. Then, this latent image is developed each time with opposing complementary color toner, and the toner image of each color is generally transferred repeatedly onto a transfer paper held on a transfer drum or a transfer belt. In such color copying machines, in order to prevent color misregistration, that is, transfer misalignment, and improve copy quality, it is necessary to synchronize the driving of the scanning optical system, photosensitive drum, and transfer drum or transfer belt. This is very important.

For this reason, conventionally, detection signals from a scanning sensor that detects the scanning start position of the scanning optical system, a transfer paper sensor that detects the trailing edge of the transfer paper, or a detection signal from a transfer paper size setting circuit that sets the size of the transfer paper have been used. The transfer start time and transfer end time are detected based on the transfer signal, and the transfer is performed so that the leading edge of the transfer paper matches the leading edge of each color toner image formed on the photoreceptor drum between these transfer start time and transfer end time. A device in which the rotational speed of the drum is variably controlled is known.

However, in such conventional color copying machines, the scanning optical system, photoconductor, and transfer body, which are non-driving bodies, are not controlled independently, resulting in misalignment during color composition (color overlapping). Sometimes. Further, since each of the non-driving bodies cannot operate independently, wasteful waiting time often occurs.

(Purpose) Therefore, the present invention has been devised to reliably prevent misalignment of the scanning optical system, photoreceptor, and transfer member as non-driving members, and to improve copying efficiency by eliminating wasted time. The purpose is to provide a color copying machine with

(Structure) In order to achieve the above object, the present invention includes separate driving sources for the scanning optical system, the photoconductor, and the transfer body as non-driving bodies, and the scanning optical system repeatedly By scanning, a color original is sequentially exposed to multiple color separations on the photoconductor, and after each latent image formed on the photoconductor is developed with opposing complementary color toner, it is reciprocated in contact with the photoconductor. In a color copying machine that repeatedly transfers images onto a transfer paper held by a transferred transfer body, each drive source has three servo control devices each independently provided with a control means for controlling the position of a non-driving body. It is characterized by the fact that it is attached.

In a device with such a configuration, the scanning optical system, photoreceptor, and transfer member, which are non-driving members, are each controlled separately and independently, making it possible to perform precise and arbitrary control operations. ing.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 shows the overall configuration of a color copying machine to which the present invention is applied. A photoreceptor belt 1 is provided in the center of the main body of the copying machine, and is transported in six directions indicated by arrows. As the photoreceptor belt 1, oPC1Se type, ZnO type, etc. are used, but it is not limited to the belt-shaped photoreceptor as in this embodiment, but a drum-shaped one can also be adopted. Further, a charger 2 and an eraser 3 are provided around the photoreceptor belt 1, and a scanning optical system 4 is provided at the next stage. This scanning optical system 4 is well known and is composed of a lamp, a plurality of mirrors, an imaging lens, etc., and scans from a home position to a length corresponding to the length of the document, and returns to the home position again. It is a repeated action. A color separation filter 5 is provided in the optical path of the scanning optical system 4. Further, a developing device 6 is provided downstream of the imaging position formed by the scanning optical system 4. This developing device 6 is
In addition to the black developer 6B for black and white copies, there is a magenta developer 6M for color copies.

It consists of a cyan developer 6C and a yellow developer 6Y. As each developing device, either a one-component type or a two-component type can be adopted.

Furthermore, a roller static eliminator 7 is disposed downstream of the developing device 6, and immediately after that, a transfer paper 8 is held and driven in one direction (for monochrome copying such as black and white copying).
Alternatively, a transfer belt 9 formed of an endless belt that is driven to move back and forth (for color copying) is provided. The transfer belt 9 holds the transfer paper 8 fed from the transfer paper cassette 10 by the paper feed rollers 11 and the registration rows 512, and performs one or more transfers. Belt materials include y, electric material (polyester film, vinylidene tetrafluoride, nylon, etc.)
is used. The transfer belt 9 is arranged such that its transfer section is close to the photoreceptor belt 1, and a transfer charge t-13 for transferring a toner image is arranged at the transfer section. Further, the transfer belt 9 is swingably installed so as to be separated from the transfer section as shown by a dashed line by a solenoid or the like (not shown). Furthermore, at a position slightly away from the transfer area,
A static eliminator 14 for removing residual charges is disposed, and a separation claw 15 for separating the transfer paper on the transfer belt 9 is swingably provided on the back (left side in the drawing) of the static eliminator 14. It is being Furthermore, a guide plate 16 for guiding the separated transfer paper is disposed immediately after the separating claw 15 so as to be close thereto. This guide plate 16 is
It extends to the fixing device 17. Note that reference numeral 18 indicates a transfer belt cleaning device for scraping off residual toner on the transfer belt 9, and reference numeral 19 indicates a cleaning device for scraping off residual toner on the photoreceptor belt 1.

Next, the control system of such a copying machine will be explained with reference to FIG.

A servo motor 21 serves as a drive source for the photoreceptor belt 1, scanning optical system 4, and transfer belt 9.
, 22 and 23 are provided separately and independently. Encoders 24, 25, and 26 are attached to each of the servo motors 21, 22, and 23, and the servo motor 22 is placed under the control of a motor control board 27, and the servo motor 21J5 and the servo motor 23
J3 is under the control of the motor control board 28.

Further, the scanning optical system 4 is attached with a scanning home sensor 30 that detects the scanning start time, that is, the home position position, and a detection signal from the scanning home sensor 30 is input to the main control board 31. Further, a position marker 32 indicating the home position is attached to the transfer belt 9, and this position marker 32 is detected by a transfer belt home sensor 33, and the detection signal is also input to the main control board 31. There is. A scanner running start signal, a photoreceptor belt speed command signal, a transfer belt reference signal, etc. are communicated between the main control board 31 and the motor control board 27, and the motor control board 27 and the motor control board 28 A transfer belt position command signal, a transfer belt speed command signal, a photoreceptor belt speed command signal, a clock pulse signal, etc. are communicated between the two.

Furthermore, the main control board 31 includes:
An operation/display control board 34 is connected,
Between the operation/display control board 34 and the main control board 31, a transfer paper size signal, a number of copies signal, a variable magnification signal, and a color/monochrome copy mode signal are communicated.

In the apparatus in this embodiment, a light image of the document is exposed onto the photoreceptor belt 1, which is transported at a constant speed, by scanning the document with the scanning optical system 4. The latent image formed is developed in the developing device 6 to obtain a toner image, and this toner image is transferred to the transfer paper 8 that is transported while being held on the transfer belt 9, thereby obtaining a copy. becomes. The transfer paper 9 is sent out from a transfer paper cassette 10 by a paper feed roller 11 and a registration roller 12 and placed on the transfer belt 9, and is transferred by an electric field generated from a transfer charger 13 at a transfer section. The transfer belt 9 and the photoreceptor belt 1 are transported in the same direction and at the same speed.

After the transfer paper 8 has been transferred, residual charges are removed by a static eliminator 14, and then it is peeled off from the transfer belt 9 by a separation claw 15, heated and fixed by a fixing device 17, and then discharged from the machine. Ru. In this case, during color copying, scanning is performed repeatedly to sequentially perform multi-color separation exposure of the color original onto the photoreceptor belt 1, and each latent image is developed with complementary color toner and repeatedly transferred to the transfer paper 8. becomes.

The transfer belt 9 is driven in one direction during monochrome copying such as black-and-white copying, but is moved back and forth in the following manner during color copying.

That is, when the transfer of the first color is completed, the transfer belt 9
is swung by a solenoid or the like (not shown) to the position shown by the dashed line and removed from the transfer section, then transported in the opposite direction, and the transfer paper 8 is returned to a position where its leading edge does not touch the transfer section and then stopped.

Then, after the transfer belt 9 is returned to the position where it contacts the transfer section again, the second color transfer is performed. When performing such reverse conveyance and second color transfer, since the first transfer has already been performed on the transfer paper 8, it will be electrostatically attracted to the transfer belt 9 side, and it will be misaligned with respect to the transfer belt 9. It is transported in one piece without causing any damage. In addition, when using a large-sized transfer paper, it is temporarily received in a transfer paper holder 20 provided so as to extend from the front end portion (left end portion in the drawing) of the transfer belt 9. By repeating these steps, color synthesis is performed and a final color image is obtained.

In such a copying operation, the transfer belt 9, photoreceptor belt 1, and scanning optical system 4 are each controlled by an independent servo motor, so that good synchronization is achieved and the three Misalignment is completely prevented. Furthermore, depending on the size of the transfer paper 8, the reverse conveyance speed (return speed) of the transfer belt 9 is changed, the movement amount (distance 1ift) of the transfer belt 9 is changed, and a short return of the scanning optical system 4 is performed. By allowing the copying process to be performed arbitrarily, the copying operation can be executed efficiently.

However, regarding such operations and operation control, the second
This will be explained using figures. FIG. 2 is a timing chart showing the operation control during color copying, in which the timing chart on the photoreceptor belt 1 is controlled based on the reference pulse, the detection output of the transfer belt home sensor 33, and the detection output of the scanning home sensor 30. The relationship between the image formation timing of each color image of Y, M, and C, the operation timing of the transfer belt 9, and the speed relationship are shown. Here, L is the maximum movement amount of the transfer belt 9, ! is the size (length) of the transfer paper 8, t is the scanning time, t2 is the return time of the scanning optical system 4, R is the distance the photoreceptor belt 1 is transported during the return of the scanning optical system 4, vo is the length of the photoreceptor The transport speed of the belt 1 is shown respectively.

First, when making a color copy, after setting the set sheet number magnification data and setting the size (length) of the transfer paper 8,
When the print switch is turned on, a copying operation is started, and first, static elimination and charging of the photoreceptor belt 1 are started.

Next, at the start timing of the scanning optical system 4, exposure scanning detected by the scanning home sensor 30 is started, and the electrostatic latent image of the color component on the photoreceptor belt 1, which is rotating at a constant speed ■o, is Image is created. Then, when the development start timing comes, the developing device starts developing complementary color toner corresponding to the image, and the electrostatic latent image is developed. Thereafter, when a time t3 seconds has elapsed since the scanning start time of the scanning optical system 4 in order to determine the transfer timing, the transfer belt 9
The transfer operation to the transfer paper 8 held above is started. The speed of the transfer belt 9 at this time is the speed of the photoreceptor belt 1 (■). The speed is the same as that of And this time t3
is a reference position of the transfer belt 9 detected by the transfer belt home sensor 33, and the leading edge of the transfer paper 8 on the transfer belt 9 is located at a position corresponding to the leading edge of the image.

On the other hand, when 11 seconds (corresponding to the length according to the original size and the transfer paper size) have elapsed from the time when the above-mentioned scanning optical system 4 starts scanning, the original scanning is finished and the scanning optical system 4 is operated by the servo motor. 22 starts the return operation. and,
From the time when the scanning optical system 4 starts scanning,
When the time t1+t3 seconds has elapsed, the scanning optical system 4
The return operation of is completed. After this, servo motor 2
2 rotates in the normal direction, this scanning optical system 4 immediately starts scanning operation,
An electrostatic latent image of the next color component is created without waiting for rotation. During this scanning, unlike the beginning, when the time ti + t3 elapses and the transfer ends, variable speed control of the transfer belt 9 is performed until the next transfer start time, and the photoreceptor belt 1 rotates at a faster speed. be done. This is within the return time t of the scanning optical system 4 considered on the photoreceptor belt 1, and during this time the transfer paper is moved by a length Li). Then, when time t1+t2+t3 elapses, it is time to start transfer, and variable control of the speed of the transfer belt 9 is completed, and the photoreceptor belt 1
The speed of V.

The transfer operation is possible as follows. The following is controlled in the same way.

That is, in the overall control by reference pulses, transfer is performed based on the transfer belt position signal detected by the transfer drum home sensor 33 and the scanning start timing signal of the scanning optical system 4 detected by the scanning home sensor 30. The start time and transcription end time are controlled. Then, the speed of the transfer belt 9 is variably controlled between the transfer end time and the next transfer start time, so that the leading edge of the transfer paper 8 is aligned with the leading edge of the image. This means that in the relationship between the speed of the photoreceptor belt 1 and the speed of the transfer belt] to 9, the transfer belt 9 returns during the return time t2.
It is variably controlled so that it moves a length (Ll) within.

In the embodiment shown in FIG. 4, in which the same components as those in the embodiment shown in FIG. has been adopted.

(Effects) As described above, the present invention provides a three-servo control system in which control means for position control are independently provided for the scanning optical system, photoconductor, and transfer body as non-driving bodies. Because it is equipped with a mounting bracket, it is possible to completely prevent positional shift during color composition regardless of the circumference or length of the photoconductor and transfer body, and it is also possible to adjust the position at any time to avoid wasted waiting time. The operations of each can be controlled, making it possible to improve copying efficiency.

Further, even when changing the magnification at an appropriate magnification ratio, operation control corresponding to the change can be executed, making zooming possible.

[Brief explanation of drawings]

1 and 2 are block diagrams and timing charts of the operation control system, FIG. 3 is a schematic diagram showing the overall configuration of a copying machine according to an embodiment of the present invention, and FIG. 4 is a block diagram and timing chart of an operation control system. FIG. 1 is a schematic configuration explanatory diagram showing the entire copying machine in the embodiment. 1... Photoreceptor belt, 4... Scanning optical system,
9... Transfer belt, 21.22.23... Servo motor, 27.28... Control board, 30... Scanning home sensor, 31... Main control board, 33... Transfer belt home sensor. Pa,,′

Claims (1)

[Scope of Claims] 1. Separate drive sources are provided for the scanning optical system, the photoconductor, and the transfer body as non-driving bodies, and the scanning optical system repeatedly scans the photoconductor. A color original is sequentially subjected to multi-color separation exposure, and the latent image formed on the photoconductor is developed each time with opposing complementary color toner, and then a transfer body is transferred back and forth so as to be in contact with the photoconductor. In a color copying machine that repeatedly transfers images onto a held transfer paper, the scanning optical system, the photoreceptor, and the transfer member as the driving sources are each independently provided with control means for controlling their positions. A color copying machine characterized by: 2. The color copying machine according to claim 1, wherein the scanning optical system as a driving source, the control means attached to the photoreceptor and the transfer member are composed of three servo control devices. . 3. The color copying machine according to claim 1 or 2, wherein the transfer body is formed of a belt body that is rotated in forward and reverse directions.