JPS59226341A - Controller of exposure position for copying machine - Google Patents

Abstract

PURPOSE:To prevent the deviation of overlapping of transferred images with simple constitution by detecting the variation of the position of a scanning system with the light of a light source passing through a lens, which is moved together with the optical scanning system, and displacing a mirror for exposure to compensate the variation of the position of the scanning system. CONSTITUTION:A light source 7 is lit by a timing signal for arrival of a transfer means at a prescribed position, and the image of the light source 7 is focused on a linear sensor 11 through a lens 10, which is moved together with a carriage 5 of the optical scanning system as one body, to detect the variation of the position of the carriage 5. A step motor is operated in accordance with this detection output, and the mirror for exposure is displaced to compensate the variance of the position of the carriage 5. Consequently, the deviation of overlapping of transferred images for individual colors or the like is prevented with a simple constitution without making the device complicated neither large-scale.

Description

Detailed Description of the Invention (Technical Field) The present invention determines the exposure position on a photosensitive drum by changing the angle of an exposure mirror. Regarding a control device.

(Prior art) Conventional multi-transfer type copying machines scan the document surface multiple times (for example, three times corresponding to the three primary colors of red, green, and blue), and perform the same number of charging steps, exposure steps, and development steps. In some cases, a transferred image is obtained through a transfer process, and then the image is fixed to obtain a single copy. This multiple transfer type copying machine is provided with a mechanical ft synchronization means such as a cam to synchronize the operations of the scanning system, photosensitive drum, and transfer drum. This ensures that no discrepancies occur.

However, in conventional multi-transfer copying machines, the scanning system, photosensitive drum,
Since the three parts of the transfer drum are synchronized, the structure of the apparatus itself is complicated, and as a result, it is difficult to maintain constant accuracy due to mechanical play and the like. Since the scanning speed must still be changed when changing the magnification, there is a disadvantage that the apparatus becomes even more complicated and larger.

(Objects and Structure of the Invention) The present invention has been made in view of the above, and is intended to prevent light from a light source from shifting in the size of a transferred image without complicating or increasing the size of the device. An exposure position for a copying machine in which fluctuations in the position of the scanning system are detected by the light received through a lens that moves with the scanning system, and the exposure mirror is displaced based on the detection results to correct the fluctuations in the position of the scanning system. A control device is provided. Hereinafter, the exposure position control device for a copying machine according to the present invention will be explained in detail.

(Embodiment) Figures 1 and 2 ((), ←), (c), and 2) show an embodiment of the present invention, in which a platen 2 on which a document 1 is placed is provided at the top of the copying machine. At the bottom, there is a scanning system 4 (light source lamp 4at mirror 4b+4ct4d+) that scans the original 1.
4es lens 4f.

and green, blue, and red color separation filters 4
A light source lamp 4a and a mirror 4b are mounted on a carriage 5). As is clear from FIG. 2(A), a box 6 is provided at one end of the platen 2, and a position detection light source 7 is provided within the box 6. Further, a slit 8 is provided below the box 6 for transmitting the light from the light source 7 to the outside. Furthermore, a lens mount 9 is fixed to one end of the carriage 5, and a position detection lens 10 is set on the lens mount 9, and the position detection lens 10 moves together with the carriage 5. Furthermore, a lens 10 is provided below the light source 7.
Linear sensor 11 (9 sensors 1laX+
11b, 11c+11d+11e+11f, 11g, 1
1h, 1li) are provided so that the position of the carriage 5 can be detected. A photosensitive drum 12 is provided below the scanning system 4 and is exposed to light by the scanning system.
It is in contact with the transfer drum 13 at a distance of 2 m. As shown in FIG. 2 ←), the transfer drum 13 is provided with a sensor actuator 17 on its outer periphery, which engages with a photosensor 20 consisting of a light emitting diode 18 and a phototransistor 19 to indicate the position of the carriage 5 to the photosensor 20. Output the reference timing signal to be checked. When the reference timing signal is output, if the light source 7 illuminates the sensor lie at the center position of the linear sensor 11 through the lens 10, the scanning system 4. The positions and speeds of the photosensitive drum 12 and the transfer drum 13 are set so that they are synchronized. In addition to the above configuration, the paper feed tray 22 that supplies the copy paper 21 to the transfer section 12a is enclosed, and around the photosensitive drum 12 there is a charging corotron 23, an exposure slit 24, and an electrostatic latent film of the photosensitive drum 12. Developing section 25 that develops images (magenta, yellow, -/an developing section 25 corresponding to green, blue, and red)
a.

25b and 211), and a cleaner 27 for removing toner from the photosensitive drum 12 after transfer. Further, the mirror 4e mentioned above is as shown in FIG. 2(C).
Mirror carriage 2 rotated by rotating shaft 29
A gear 30 is fixed to the rotating shaft 29, and the gear 30 meshes with a worm gear 31. The worm gear 31 is connected to a step motor 33 via a shaft 32. Furthermore, a transport belt 34 and a fixing section 35 are provided downstream of the transfer section 12a, and
A control section 36 (eg, an Eva microcomputer) for controlling the operation of the copying machine 3 is provided at an appropriate position within the copying machine. Control part 3
6 is the sensor signal of various sensors in the copying machine (including the linear sensor 11 and the photo sensor 20) or the console (
an input interface 36a that inputs operation command signals from a computer (not shown); a ROM 36b that stores programs necessary for arithmetic processing of input signals; a CPU 36c that performs predetermined calculations based on the programs; RAM 36 d for temporarily storing information and data, etc.;
(including the step motor 33) or a display section of a console (not shown).

To explain the operation in the above configuration, when the start key (not shown) of the console (not shown) is turned on after placing the original 1 on the platen 2, the scanning system 4 starts scanning the original under the control of the control unit 36. Perform scanning. During the first document scanning, a green filter (not shown) is placed in the optical path, and the photosensitive drum 12 is exposed to the green component in the scanning light. The developing section 25a develops the latent image resulting from the exposure using magenta toner, and the developed image is transferred to the copy paper 21 fed from the paper feed tray 22 and held by the transfer drum 13 at the transfer section 12a. Thereafter, when the second document scan is performed, a blue filter (not shown) is placed in the optical path, and the photosensitive drum 12 is exposed to the blue component of the scanning light. The latent image formed by the path light is transferred to the developing section 25b.
is developed with yellow toner, and this developed image is transferred to the copy paper 21 held by the transfer drum 13 at the transfer section 12a. Finally, when the third document scan is performed, a red filter (not shown) is placed in the optical path, and the photosensitive drum 12 is exposed to the red component in the scanning light. The developing section 25c develops the latent image based on this exposure using cyan toner, and the copy paper 21, which is still gripped by the transfer drum 13, undergoes the final transfer of this developed image.

When the photosensitive drum 12 and the transfer drum 13 rotate during exposure based on the first to third document scans, and the sensor actuator 17 engages with the photosensor 20 and turns on the sensor 20, the control that inputs it A control signal from the section 36 turns on the light source 7 in the box 6 and emits light downward through the slit 8. Carriage 5 at that point
The position at which light is focused onto the linear sensor 11 via the position detection lens 10 provided at one end of the linear sensor 11 differs depending on the position of the linear sensor 11 . When the linear sensor 11 is turned on, its sensor signal is input to the control unit 36, and the control signal from the control unit 36 is output to the step motor 33 to adjust the angle of the mirror 4e according to the position of the carriage 5. A detailed explanation will be given below using the time chart shown in FIG. FIG. 3 0) shows a case where the carriage 5 moves at a predetermined timing and the central sensor lie of the linear sensor 11 is turned on.

When the photo sensor 20 is turned on while the carriage 5 is moving, the light from the light source 7 is transmitted to the linear sensor 1 by the position detection lens lO.
One of the sensors reaches sensor lie.

When the linear sensor signal lie is input to the control section 36, the control section 36 controls the scanning system 4, the photosensitive dosing shim 12, and the transfer drum 13.
It is determined that the mirrors 4e and 4e are synchronized, and no control signal is output to the mirror 4e. Next, in FIG. 3 ←), since the carriage 5 was delayed by the predetermined timing, the focusing position of the light by the position detection lens 10 was shifted, and the sensor l of the linear sensor 11
The case where the part la is turned on is shown. When the sensor 20 is turned on and the sensor lla is turned on, the control unit 36 determines that the movement of the carriage 5 is delayed by a predetermined timing, outputs a control signal of four positive pulses, and performs a step. The motor 33 is driven. Therefore, the mirror 4e is displaced counterclockwise by an angle θ to compensate for the scanning delay and prevent image shift. Finally, Figure 3 f → shows carriage 5.
is ahead of a predetermined timing, the focusing position of the light by the position detection lens 10 is shifted, and when the sensor 2o is turned on, the sensor lli of the near sensor 11 is turned on. When the sensor signal of the sensor lli is determined by the controller 36 to be ahead of the scanning timing, the
The control signal of negative pulses is output clockwise at an angle θ
The advance of the scan is compensated for by displacing the mirror 4e by the same amount. As a result, the exposure position by the mirror 4eK and the transfer position onto the copy paper 21 match, and it is possible to avoid multiple displacements of multiple transferred images. Similarly, the displacement of the mirror 4e is shown in the relationship shown in FIG. 4 as follows.

e = "tan-" 2 L where θ is the displacement angle of the mirror 4e, L is the distance between the mirror 4e and the photosensitive drum 12, and e is the amount of displacement of the latent image. Incidentally, sufficient correction can be made when e≦1.5 or so. Also, in the above explanation, we have explained the case where lla or 11i in the beam knee V sensor is turned on, but l
lb.

Even when 11c, lld, 11f, 11g, and llb are each turned on, it is possible to output the number of pulse control signals corresponding to each sensor and displace the mirror 4e according to the advance or delay of scanning.

In the above embodiment, the linear sensor 11 was composed of sensors lla to lli, but the linear sensor 1
If the total length of 1 is 2 sub, then 10 m and 200
sensors are required. Furthermore, the magnification of the image of the light source 7 on the linear sensor 11 can be controlled by adjusting the position of the lens 10, but the magnification must be determined according to the width of the slit 8 and the resolution of the linear sensor 11. Furthermore, although the above embodiments have been described with respect to a multi-transfer copying machine, the present invention can also be applied as a registration lane correction device for a monochrome copying machine, and can also be applied to adjusting an optical system during assembly.

(Effects of the Invention) As explained above, according to the exposure position control device for a copying machine according to the present invention, fluctuations in the position of the scanning system are detected by receiving light from a sound source through a lens that moves together with the scanning system. Since the exposure mirror is displaced based on the detection result to correct the positional fluctuation of the scanning system, it is possible to prevent severe scratches V on the transferred image without complicating or increasing the size of the apparatus.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the structure of an exposure position control device for a copying machine according to the present invention. FIG. 2B), (-) is an explanatory diagram showing a scanning system lens and a linear sensor. FIG. 2C→ is an im-chart showing the sensor actuator provided on the transfer drum and the sensor provided on the outer periphery of the transfer drum. FIG. 4 is an explanatory diagram showing the relationship between the amount of rotation of the mirror and the amount of compensation for the incident position on the photosensitive drum. Explanation of symbols: 1: Original, 2: Platen, 4: Scanning system, 5: Carriage, 6: Box,
7...Light source for position detection, 8...Slit,
9... Lens mount, 10... Position detection lens, 11... Linear sensor, 12... Photosensitive drum, 12a... Transfer section, 13... Transfer drum, 17... Actuator for sensor , 20...
Photo sensor, 21... Copy paper, 25...
・Developing section, 28...Mirror carriage, 29...
・Rotating shaft, 30... Gear, 31...
Worm gear, 32...shaft, 33...step motor, 36...control unit. Figure 2Figure 2

Claims (1)

[Scope of Claims] In a sheet copying machine that converts copies into copies through each process of document scanning, exposure, preservation, transfer, and fixing, when the transfer means reaches a predetermined position, a basic timing signal is activated. means for outputting a position signal corresponding to the position of the scanning system by receiving light from a light source through a lens that moves together with the scanning system when the timing signal is output; 1. An exposure position control device for a copying machine, comprising means for displacing an exposure mirror based on.