JPS60107048A - Exposing position control device for color copying machine - Google Patents

Abstract

PURPOSE:To set exactly the exposing position on a photosensitive body, and to prevent a shift of a multiple transfer by stopping a color separation filter at a reference position, and thereafrer, displacing it in accordance with a correction quantity. CONSTITUTION:A filter provided between a photosensitive body and a lens is displaced by an angle theta clockwise or counterclockwise, corrects an overdelay or an overadvance of scanning, and prevents the generation of a shift of an image. A correction quantity X of an image shift on the photosensitive drum is derived. from a correcting angle theta displaced from the reference position of the filter and a thickness (t) of the filter. When a refractive index of air in the optical path, and a refractive index of the filter are denoted as n0 and n1, respectively, the correction quantity X is derived from an expression ( I ). theta' in the expression ( I ) is determined by an expression (II). This X corresponds to a shift generated in the incident position to the filter and an emitting position from the filter on the basis of displacing the filter by an angle theta from the reference position, and the image shift can be prevented by selecting an angle Q in accordance with a position variation of the scanning system and the photosensitive drum, etc.

Description

Detailed Description of the Invention (Technical Field) The present invention is capable of accurately setting the exposure position of photosensitive potted soil by stopping a color separation filter at a reference position and then displacing it in accordance with the amount of correction. The present invention relates to an exposure position control device for a color copying machine that prevents misalignment.

(Prior Art) In a conventional color copying machine, for example, an original rlz+ is passed through a plurality of times (for example, three times corresponding to the three primary colors of red, green, and blue), and the same number of charging steps, fogging steps,
There is a method in which a transferred image is obtained through a development process and a transfer process, and then the image is fixed to obtain a single sheet of color coffee. This color intermediate copying mK is equipped with a mechanical synchronization means such as a cam to synchronize the operations of the scanning system, photosensitive drum, and transfer drum. I try not to.

However, in conventional color copying machines, the scanning system, photosensitive drum, and transfer drum are synchronized using mechanical synchronization means such as cams, which makes the structure of the device itself complicated and As a result, it becomes difficult to maintain constant accuracy due to mechanical play and the like. Also, when changing the magnification, it is necessary to switch between constant scanning and concealment.
This has the disadvantage that the device becomes even more complicated and larger.

(Objects and Structure of the Invention) The present invention has been made in view of the above, and in order to accurately prevent the shift of the weight of the transferred image without complicating or increasing the size of the device, it is possible to change the position of the scanning system. is corrected by the displacement of the color separation filter, and during this correction, after displacing the color separation filter by a predetermined displacement amount (larger than the fine adjustment displacement amount) from the position of the preceding color separation operation, the subsequent color separation filter is The present invention provides an exposure position control device for a color separation scalar copying machine, which stops a color separation filter in a color separation operation at a predetermined reference position.

Hereinafter, the exposure position control device for a color copying machine according to the present invention will be explained in detail.

(Example) Fig. 1 and Fig. 2 0), (B), and C) show an example of ``Non-explosion'', in which a platen 2 on which the original Tachibana 1 is placed is provided at the top of the copying machine, A scanning system 4 for scanning WaI is provided at the bottom thereof. The scanning system 4 includes a light source lamp 4a and mirrors 4b, 4e, and 4d.

4e, a lens 4f, and a color separation filter 6. The color separation filter 6 has green, blue, )” #O7
4 routers 5a, 5b, 5c at intervals of 1200 7ya 7to6
One end of the shaft 6m is a belt 8 that transmits the drive of the step motor 7.
It is linked with. Each filter 5a, 5b, 5c has an actuator 10c, 10d, 10ee at the tip thereof, and a photosen v9 consisting of one light emitting diode and a phototransistor.
When one of the actuators 106, 10d, and 10e engages, a position signal for that filter is generated. Further, a light source lamp 4a and a mirror 4b are placed on a carriage 5. As is clear from FIG.

A photosen length 12 consisting of a light emitting diode 12a and a phototransistor 12b is fixed to one end of the tube 5 at a fixed position through which the sensor actuator 10& passes. Further, a photosensitive drum 13 is provided below the scanning system 4 and is exposed to scanning light.
It is in contact with The transfer drum 14 is provided with a sensor actuator 10b on its outer periphery as shown in FIG. In addition to the configuration described above, in which the drive shaft 15 of the transfer drum 14 is provided with a pulse generator 16, there is also a feeder for supplying copy paper 17 to the transfer section 13a. A paper tray 18 is provided,
There is a charged corotron 19 around the photosensitive dodim 13.
, a mackerel slit 20, and a developing section 21 that develops the electrostatic latent image on the photosensitive drum 13 (corresponding to green, blue, and red, there are magenta, yellow, and red developing KB 21 a).
.

21b and 21c), and a cleaner 22 for removing toner from the photosensitive drum 13 after transfer. Furthermore, a transport belt 2 is provided at a stage subsequent to the transfer section 13 &
3 and a fixing section 24, and a control 529 (for example, a microcomputer) for controlling the operation thereof is provided at a predetermined position inside the copying machine. [1] The @ section 29 has an input interface 29a for inputting sensor signals from various sensors T (including the C sensor 12 and 17) in the extraction box or operation command signals from a console (not shown), and input signals. ROM that stores the programs necessary for the arithmetic processing of
29 b, and a CP that performs predetermined calculations based on the glogram.
U 290, an RAI system 29d that temporarily stores results and data, and an enlarged console (not shown) that controls various control objects of the copying machine (including step 7) based on the calculation results. The operation of the genus 〇 or higher having an output interface 29e that outputs a control signal to the display section will be explained.

After placing the document 1 on the platen 2, turn on the start key (not shown) on the console (not shown), and the control unit 2
The scanning system 4 scans the original under the control of 9. During the first document scan, the green filter 5a of the color separation filter 6
is placed in the optical path, and the photosensitive drum 13 is exposed to the green component of the scanning light.The developing section 21a develops the latent image by the exposure with magenta toner, and this developed image is fed from the paper feed tray 18. The copy paper 17 held by the transfer drum 14 is transferred at the transfer section 13'a. After that, when the second document scan is performed, the color separation filter 60 and the blue filter 5b are placed in the optical path, and the photosensitive drum 13 is exposed to the blue component of the scanning light. 21b is developed with yellow toner, and this developed image is transferred to the copy paper 17 gripped by the transfer drum 14 in the transfer section 13a.Finally, when the third document scan is performed, the color separation filter 6 and the defilter are 5c is placed in the optical path, and the photosensitive drum 13 is exposed to the red component in the scanning light.The developing section 21e develops a latent image based on this exposure with cyan toner, and this developed image is held by the transfer drum 14, and the photosensitive drum 13 is exposed to the red component in the scanning light. The original copy paper 17 undergoes the final transfer◎ The control of the color separation filter 6 will be explained below in detail with reference to Fig. 3 (a), (b), and f. - Fig. 3 0) shows the scanning transfer drum, This shows a case where the photosensitive drums are synchronized.Prior to the start of document scanning, the transfer drum 14 is synchronized with the photosensitive drum 1.
3, the seventh actuator 10b provided on the transfer drum 14 blocks the light from the light emitting diode 17m and turns on the photo sensor T17 (time t1).
.

As a result, a pulse detection start signal is input to the control unit 29, and the pulse signal of the pulse generator 16 is counted.When the scanning system 4 has scanned a certain distance, the sensor provided at one end of the carriage 5 The actuator 10m blocks the light from the light emitting diode 12m and turns on the photo sensor 12 (time t). When the photosensor 12 is turned on, the control section 29 finishes counting the pulse signals, compares the counted value n with a predetermined value N, and, based on the determination of N-n, outputs no control signal. Therefore, the color separation filter 6 that puts the filter 5m, 5b, or 5a into the optical path does not receive a displacement command for color shift correction.

Next, 3rd @←) Indicates a case where the forward scanning system is ahead of schedule. ・Prior to the start of document scanning, when the transfer drum 14 rotates, the photosensor 17 turns on and starts counting pulse signals, and the photosensor 12 ◎The control unit 29 compares the counted value with a predetermined value N, and outputs a control signal according to the difference between k(N and pN-) to control the step motor 33. The filters 5a and 5b are rotated clockwise to perform color separation through the belt 8.7.The filters 5a and 5b are exposed in the optical path of the Iltero.

Alternatively, 5c is rotated clockwise by a predetermined displacement amount from a reference position (described later) (based on a positive control signal). FIG. 3 t-t shows a case where the scanning system 4 is behind schedule, and since the count value P and the predetermined value N are P)N, the color separation filter 60 comes out into the optical path. filter 5a.

5b or 5c is rotated counterclockwise by a predetermined displacement amount from the reference position (based on a negative control signal). As is clear from the above description, the filters 5a, 5b, 6, or 5C are displaced clockwise or counterclockwise by an angle θ to correct delays or excessive scan advances and prevent image shifts from occurring. The correction amount X of the image shift on the photosensitive drum 13 is calculated by the correction angle θ of displacement of the color separation filters 5a, 5b, and 5a from the reference positions and the thickness t of the filters. The relationship between X, θ, and t is shown in FIG. 4 ('r) and (b).

The refractive index of the air in the optical path is 16, and the color separation filter is 5 m.
b, if the refractive index in 5a is nl, then x = tπFs・B
θl in the above equation is determined from θ′ w 131-” (”!JL+ 1110).

This X is the color separation filter 5a, 5b, or 5
This corresponds to the deviation that occurs between the incident position and the output position of the color separation filter 5a, 5h or 5c due to the displacement of c from the reference position by the correction angle θ, and the difference between the scanning system 4 and the photosensitive drum 13
Alternatively, image shift can be prevented by selecting the correction angle θ according to the positional variation with respect to the transfer drum J4. The color separation filters 5a, 5b, 5a are grooved so as to be rotationally driven by a step motor 7, and are rotated by a displacement amount corresponding to the above-mentioned pulse number count from a stopped reference position.

The filter 6 has a predetermined displacement angle (for example, 1
After being rotated by 20°-19M (θ is the maximum correction displacement angle), when it is detected that the color separation filter of the subsequent color separation operation has passed through the photo sensor 9 based on the operation of the photo sensor +j9, the color separation filter to stop. This stop position is used as a reference position, and from this reference position it is displaced by an amount of displacement according to the counted value of the number of pulses mentioned above. ◎Hereafter, this amount of displacement is controlled by Le1.
, (b) I will explain it to you in detail. Assume that exposure is now being performed using the filter 5a. When the scanning system 4 finishes scanning the document surface and enters the return operation (Fig. 5 (a)
area JL), the filter 6 has the above-mentioned displacement angle (120°-
Rotate clockwise by θM) and move to the area (1) in Figure 5 (b).
)), when the filter 5b enters the optical path and the sensor actuator 10d passes the photosen 'v''9, it stops (region (I+) in Fig. 5(b)).This stopping position is the reference position. , gi adjustment movement is performed from this reference position to a corrected displacement position based on the pulse count value. In FIG. 5(b).

C is a gentle movement in the counterclockwise direction, and D is a subtle movement in the clockwise direction. Here, the amount of movement of B is 1t of movement of A.
The reason why υ is larger than i is because the complete adjustment movement 11 of C is in the anti-chronological direction, so the movement of B increases the amount of displacement required to rotate clockwise and displace to the reference position. be.

〔Effect of the invention〕

As explained above, according to the exposure position control device for a color first copying machine according to the present invention, the variation in the position of the scanning system is corrected by the displacement of the color separation filter, and at the time of correction, the color separation filter is After a predetermined displacement amount (larger than the fine adjustment displacement amount) from the color separation operation position, the color separation filter for the subsequent color separation operation is stopped at a predetermined reference position, and then the corresponding color is By displacing the decomposition filter in accordance with the amount of correction, it is possible to accurately prevent the weight shift of multiple transfer images without complicating or increasing the size.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the structure of an exposure position control device for a color close-up camera according to the present invention. Figure 2 (A) is an explanatory diagram showing the scanning system and photosensor. is an explanatory diagram showing the color separation filter and step motor ◎Figure 3 ('r) ~ (
-9 is a time chart showing operations. Figure 4 (a) (cl.
) is a time chart showing the relationship between the amount of rotation of the mirror and the amount of correction of the incident position on the photosensitive drum. Explanation of symbols l... Original, 2... Platen, 4... Scanning system, 6
... Color separation filter, 7... Step, motor, 9.
...Photosensor, 12...Photosen? , 13... Photosensitive drum, 14... Transfer drum, 17... Photo sensor, 21... Developing section. Forgive me! MA Fuji Xerox Co., Ltd. Agent Patent attorney Shin Matsubara 2 Patent attorney Jo Muraki Junma Patent attorney Taira 1) Yudo Tadashi Patent attorney Atsushi Ueshima - Patent attorney Hitoshi Suzuki Figure 1 Figure 2 Figure 3 (a) Baraya Shimo issue Figure 4 (a) (b)

Claims (1)

[Scope of Claims] In a color copying machine that obtains one color copy by fixing multiple transfer images obtained by repeating the steps of document scanning, exposure, development, and transfer a number of times according to the number of color separations, a transfer means is provided. Alternatively, means for outputting a reference timing signal when the photoreceptor reaches a predetermined position; means for outputting a position signal according to the position of the scanning system when the reference timing signal is output; and the color color separation filter means having a plurality of color separation filters according to the number of separations; and after displacing the color separation filter means by a predetermined amount of displacement from the position of the preceding color separation operation, 9. An exposure position control device for a color copying machine, comprising: control means for stopping a color separation filter at a predetermined reference position and then displacing the color separation filter in accordance with the position signal.