JPS60113221A - Exposure position controller for copying machine - Google Patents

Abstract

PURPOSE:To prevent deviation of an overlap of multiple transfer images by returning an exposure position adjusting member to the original position before adjustment, displacing the member by a specific extent and then returning and rotating the member, and stopping the member through the operation of a sensor and them performing the adjustment. CONSTITUTION:When the carriage 5 of a scanning system moves at specific timing and light from a light source 7 reaches the sensor 11, a control part 36 judges that the scanning system 4, a photosensitive drum 12, and a transfer drum 13 synchronize with one another, and does not output a control signal for displacing a glass plate 40 for exposure position adjustment. When the carriage 5 deviates, the sensor 11 turns on, the control part 36 outputs a pulse to drive a motor 33, and the adjusting glass plate 40 is displaced to compensate image deviation. When the glass plate 40 is displaced in said process, it is displaced by a specific extent after scanning and then rotates in the opposite direction to engage an actuator 43 with the sensor 46, which is turned on to stop the glass plate 40.

Description

[Detailed Description of the Invention] [Technical Field] The present invention aims to move a transparent plate for exposure position adjustment to a reference stop position in order to prevent accumulation of errors in control amounts due to repeated control and to perform highly accurate adjustment operations. The present invention relates to an exposure position control device for a copying machine that adjusts the exposure position from

[Background technology]

2. Description of the Related Art As an exposure position control device for a copying machine, one that adjusts the exposure position using a transparent plate has been proposed. This exposure position control device for copying machines mainly consists of a scanning system, a photosensitive drum, and a transfer drum. A transparent plate is provided to adjust the

In the above configuration, when document scanning is started, the scanning system
The state of movement of the photosensitive drum and the transfer drum is detected, and the exposure position of the photosensitive drum is adjusted by changing the angle of the transparent plate through which the scanning light passes, thereby reducing the overlap of multiple transfer images. This is to prevent misalignment.

However, according to this exposure position control device for copying machines, errors based on the accuracy of the drive unit (for example, a step motor) that rotates the transparent plate and the torque transmission system accumulate during repeated copying, resulting in・After use, the accuracy of angle adjustment becomes less accurate and the weights of multiple transferred images tend to shift.

[Object and structure of the invention]

The present invention has been made in view of the above, and in order to prevent the accumulation of errors in the control amount due to repeated copying operations, and to prevent the shift of the weight of multiple transferred images even during long-term use.
The transparent plate installed between the exposure mirror and the photosensitive drum is returned from the adjustment position of the previous exposure operation to the original position before adjustment, and after being displaced by a prescribed angle in a prescribed direction from this original position, it is moved in the opposite direction. To provide an exposure position control device for a copying machine, which gives a return rotation of 1, stops by the operation of a sensor placed at a reference position during the return rotation, and performs adjustment according to the control amount from this stop position. be.

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

〔Example〕

Figures 1 and 2 (A), ←) 1 (C) are the present invention 041
As an example, a platen 2 on which a document 1 is placed is provided at the top of the copying machine, and a scanning system 4 that scans the document 1 is provided at the bottom of the platen 2.
(Composed of light source lamp 4az, mirrors 4b, 4c, 4d, 4e lenses 4f, and green, blue, and red color separation filters 4g; light source lamp 4a and mirrors 2-4b are placed in the carrier and mount 5). It is provided.

As is clear from FIG. 2(A), a hole 6 is provided at one end of the carriage 5.

A position detection light source 7 is provided inside the jig 6, and the light source 7 moves together with the carrier and jig 5. Further, a slit 8 is provided below the box 6 for radiating the light from the light source 7 to the outside, and a lens mount 9 is fixed at a predetermined position of the moving path of the carriage 5, for example, at the center thereof. A position detection lens 10 is set, and below the lens 10 there are 9 sensor sensors 11 (9 sensors lla, ll).
b, llc, lid, Ile.

11f, l1g, llb, 1lit) are provided so that the position Rt of the carriage 5 can be detected.

Further, a glass plate 4o for adjusting the exposure position is provided between the exposure lens 4c and the exposure lens 24. This exposure position adjustment glass plate 4o is supported by a glass support member 41, as shown in FIG.
It is fixed to the step motor 33 via a shaft 42't- connected to the motor 1, and is rotatable by the drive of the step motor 33. Further, a sensor actuator 43 is provided at one end of the glass support member 41 that supports the glass plate 4 for adjusting the exposure position, and a light emitting diode that emits a signal when the glass plate 40 is in the sensor operating position. A photosensor 46 consisting of a phototransistor 44 and a phototransistor 45 is provided. A photosensitive drum 12 that is exposed to scanning light is provided below the scanning system 4, and is in contact with the transfer drum 13 at a transfer portion 12a.

As shown in FIG. 2(c), the transfer drum 13 is provided with a sensor actuator 17 on its outer periphery, and a photo sensor 20 consisting of a light emitting diode 18 and a phototransistor 19.
The reference timing signal for confirming the position of the carriage 5 is output in addition to the photosensor. When the reference timing signal is output, if the light source 7 illuminates the sensor 1letffl at the center position of the linear sensor 11 through the lens 1o, the positions and speeds of the scanning system 4, photosensitive trim 12, and transfer drum 13 are adjusted so that they are synchronized. is set. In addition to the above configuration, the copy paper 21t-
A paper feed tray 22 for supplying paper is provided, and a photosensitive drum 1 is also provided.
Surrounding area 2 is a charging corotron 23 and an exposure slit 24.
and a developing section 25 (which develops the electrostatic latent image on the photosensitive drum 12)
Compatible with green, blue, and red. 125 m of magenta, yellow, and cyan development.

25b and 25c), and a cleaner 27 for removing toner from the photosensitive drum 12 after transfer. Furthermore, a transport belt 34 is provided after the transfer section 12m.
and a fixing section 35, and a control section 36 (for example, a microcomputer) for controlling the operation thereof is provided at an appropriate position within the copying machine 3. The control unit 36 includes an input interface 36g that inputs sensor signals from various sensors (including the linear sensor 11 and photo sensor 20i) in the copying machine 3 and operation command signals from a console (not shown), and arithmetic processing of the input signals. ROM that stores the programs necessary for
36b and 0P that performs predetermined calculations based on the program.
U36c and RA that temporarily stores calculation results and data.
M 36 d and various control objects of the copying machine 3 (including the light source lamp 7 and the step motor 331) based on the calculation results.
, or an output ink face 36e for outputting control signals to a display on a console (not shown).

To explain the operation in the above configuration, after placing the original 1 on the platen 2, when the start key (not shown) of the console (not shown) is turned on, the scanning system 4 is controlled by the control unit 36. scans the original. During the ``1st original optical scanning, a green filter (not shown) is placed in the optical path, and the photosensitive drum 12 is exposed to green components in the scanning light.The latent image resulting from this exposure is transferred to the developing section 25.
The copy paper 21, which is developed with magenta toner a 'bX' and is fed from the paper feed tray 22 and gripped by the transfer drum 13, undergoes transfer in the transfer section 12a. After that, when the second document scan is performed, a blue filter (not shown) is placed in the optical path, and the photosensitive drum 1
2 is exposed by the blue component in the scanning light. The developing section 25b develops the latent image resulting from the exposure using electrotoner, and the developed image is transferred onto the copy paper 21 held by the transfer drum 13 at the transfer section 12a. When the third document scan is finally 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 developed image is applied to the copy paper 22 held by the transfer drum 13.
receives the final transcription.

Based on the first to third scans of the document, the control that inputs the rotation of the photosensitive drum 12 and transfer drum 13 during exposure, and the sensor actuator 17 engaging with the photosensor 20 and turning on the sensor 20. The light source 7 in the box 6 is turned on by a control signal from the section 36, and emits light to the linenase/sustainer 11 through the slit 8 and the lens 10t.

As a result, 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 360 is output to the step motor 33. Adjust to angle 1.

A detailed explanation will be given below using the time chart shown in FIG. 1g3 (a) shows a case where the carriage 5 moves at a predetermined timing and the sensor lie of the linear sensor 11 is turned on. Carry, Ji5 is moving Photosenna 2
0 is turned on, the light from the light source 7 reaches the sensor lie of the linear sensor 11. The linear sensor signal 11e is the control unit 3
6, the control unit 36 controls the scanning system 4 and the photosensitive drum 12.
It is determined that the transfer drum 13 is synchronized, and a control signal for displacing the exposure position adjusting glass plate 40t is not output. Next, FIG. 3(b) shows a case where the carriage 5 moves beyond a predetermined timing, so that among the linear sensors 1 and 1, the sensor lla is turned on. When the sensor 20 is turned on and the sensor l1m is turned on, the control unit 36
determines that the movement of the carry and mover 5 is delayed by a predetermined timing, and outputs a control signal of 4 positive pulses to drive the step motor 33t. Therefore, the exposure position adjusting glass plate 40 is displaced counterclockwise by an angle θ to fully compensate for the scanning delay and prevent image shift from occurring. Finally, FIG. 3(c) shows a case where the carriage 5 is ahead of the predetermined timing, so when the sensor 20 is turned on, the sensor lli of the linear sensor 11 is turned on. When the control unit 36 determines that the timing of scanning is advancing based on the signal, it outputs a control signal of four negative pulses, displacing the glass plate 40 for adjusting the exposure position by an angle θ clockwise, and thereby advancing the scanning. As a result, the exposure position and the transfer position to the copy paper 21 match, and it is possible to avoid multiple displacement of the multiple rotation f image.
The figure shows the relationship between the rotation angle of the exposure position adjusting glass plate 40 and the amount of correction of the exposure position. Glass plate 40 for adjusting exposure position
Assuming that the thickness of t1 is 01, the amount of deviation X when the exposure position adjusting glass plate 40 is rotated by an angle θ is the refractive index in air? If no and fc, then the following is true.

x = t・□・self(θ−θ′) Possible θ θ′=aln (−auxiliary “, =θ) 1 The amount of deviation x from the previously detected position of the scanning system and the photoreceptor or transfer drum The displacement angle θ, that is, the rotation angle of the step motor, is given according to the amount of misalignment, and even if there is misalignment between the scanning system and the photoreceptor or transfer drum, it is possible to always obtain good copies without color misregistration during transfer. can.

The thickness t of the exposure position adjusting glass plate 40 may be determined from the step angle of the step motor and the correction amount.

Next, the exposure position adjustment glass plate 4o, which was displaced in the previous exposure operation to completely correct the deviation of the exposure position on the photosensitive drum, is returned to its original position before adjustment, and further The adjustment operation will be explained based on FIG. 5(a).

The exposure position adjustment glass plate 40 is at the reference position (5th
(in Fig. 0) When the scanning system 4 starts scanning, a deviation in the exposure position between the scanning system 4 and the photosensitive drum 12 is detected by the above-described operation, and a control signal corresponding to the amount of deviation is sent to the step motor 33. The step motor 33t-, [moves]. In addition, the glass plate 40 for adjusting the exposure position is shown in FIG.
As shown in (11) of b), the angle changes and the exposure position is adjusted (in this example, it is adjusted counterclockwise). When the scanning of the document surface is completed, the exposure position adjustment glass plate 40
is rotated in the opposite direction by an amount of displacement equal to the amount of displacement during the previous exposure position adjustment and returned to the original position before adjustment (Fig. 5 (
b) 01D). That is, since the position of the exposure position adjusting glass plate 40 after the change is not constant but fluctuates, the initial conditions will be different when rotating in the opposite direction, and even if you try to return to the reference position, there will be differences in accuracy, kinetic inertia, etc. It is inevitable that some deviation will occur. Therefore, the glass plate 40 for adjusting the exposure position is rotated clockwise by a certain pulse (a certain amount of movement) ((ψ) in FIG. 5(a)), and then rotated counterclockwise, and the exposure position By engaging the sensor actuator 43 provided on the adjustment glass plate 40 with the entire photo sensor 46 and turning on the sensor 46'ft, the exposure position adjustment glass plate 40 is stopped (as shown in FIG. 5(A)). @).

This position where the exposure position adjustment glass plate 40 stops is the reference position, and the next exposure scan starts, and the exposure position is adjusted by a control signal corresponding to the new exposure position shift amount (
For example, in (ii)' of Fig. 5←), in this case, adjust clockwise), and then the above operation is repeated.

By rotating the glass plate 4 in a certain direction by a certain number of pulses and then reversing it in this manner, the initial conditions at the time of reversal can be made the same.
0 accurately at the reference position.

The number of moving steps and moving direction of the step motor 33 related to the above changes in the exposure position adjusting glass plate 40 are stored in advance in the ROM 36 b of the control unit 36 as a control program, and when the scanning system 4 returns, the above-mentioned series of steps are stored in advance as a control program. Adjustment operation for a predetermined angle change is performed by accurately returning the exposure position adjustment glass plate 40 to a predetermined reference position and waiting by the stop operation ((iii) 4v) (v) in FIG. 5()). Now you can start. In addition, (i) in Figure 5 (b)
The operations )' to ω' correspond to the middle to (ψ) in FIG. 5(a), except that the adjustment displacement in (ii)' is clockwise, so a detailed explanation will be omitted.

In addition, Fig. 5 (c) and 5) are based on the movement of the carriage 5.
The scanning exposure timing and the adjustment timing of the glass plate 40 are shown in FIG.
-Qy correspond to the states with the same symbols in FIG.

〔Effect of the invention〕

As described above, according to the exposure position control device for a copying machine according to the present invention, the transparent plate provided between the exposure mirror and the photosensitive drum is returned from the adjustment position of the previous exposure operation to the original position before adjustment. After displacing the original position by a predetermined angle in a predetermined direction, a return rotation is applied in the opposite direction, and during the return rotation, a sensor placed at a reference position of 1 t is activated to stop the movement, and from this stop position, according to the control amount. Since the adjustment is performed, it is possible to prevent the accumulation of errors in the control amount due to repeated copying operations, and it is possible to prevent deviations in the overlap of multiple transfer images even when used for a long period of time.

[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. 2(a) is an explanatory diagram showing the scanning system, lens, and linear sensor. FIG. 2(b) is an explanatory diagram showing a transparent plate for exposure position adjustment and a step motor. FIG. 2(c) is an explanatory diagram showing a sensor actuator provided on the transfer drum and a sensor provided on the outer periphery of the transfer drum. FIG. 3 is an explanatory diagram showing the relationship with the rotation angle of the glass plate for exposure position adjustment. FIGS. 5(a) and 5(b) are explanatory diagrams showing the operation of returning the light-transmitting plate for exposure position adjustment to a predetermined position. FIG. 5(c) is a time chart showing the operation of the scanning system 4. FIG. 5) is a time chart showing the operation of the transparent plate for exposure position adjustment. 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...Lens for position detection, 11...Linear sensor, 12...Photosensitive drum, 13...Transfer drum, 17...Senna actuator, 20.
... Photo sensor, 21 ... copy paper, 25 ... developing section, 36 ... control section, 40 ... glass plate for adjusting exposure position, 41 ... glass support member, 43 ... sensor i actuator for 44... light emitting diode, 4
5... Phototransistor, 46... Photosensor, Fig. 1 Fig. 2 Fig. 2 Fig. 2 c) ())) Fig. 3 36 --------
---------f Ct A No. 2 - 6 [Drum 1 and Mbui A4 2 T Linear] No. 43 No. 11 (b) (〃)' tiiif wo/)'

Claims (1)

[Scope of Claims] In a copying machine that obtains a copy through each process of document scanning, exposure, transfer, and fixing, means for outputting a reference timing signal when a transfer means reaches a predetermined position; means for outputting a position signal corresponding to the position of the scanning system when the signal is output; and an exposure means located between the exposure mirror and the photosensitive drum to adjust the original position on the photosensitive drum by changing the angle thereof. A transparent plate for position adjustment, and a control means for controlling an angle change of the transparent plate for exposure position adjustment based on the position signal, and the control means is configured to move the transparent plate for exposure position adjustment in advance of the light transmission plate for exposure position adjustment. a first control step of returning the exposure operation from the adjustment position to the original position before adjustment; a second control step of displacing the exposure operation in a predetermined direction by a predetermined angle; and a second control step of displacing the exposure operation by a predetermined angle in a predetermined direction. a third control step in which the device is displaced from the position in the opposite direction to the aforementioned direction and stopped by actuation of a senna placed at a reference position; and a third control step in which the device is displaced by an angle corresponding to the position signal from the stopped position by the actuation of the senna. An exposure position control device for a copying machine, characterized in that it performs each of the control steps in step 4.