JPS6319671A - Color image recorder - Google Patents

Abstract

PURPOSE:To eliminate a color shift at the time of color superposition by providing an adjusting means which adjusts the image formation start timing of plural image formation units. CONSTITUTION:The image formation timing adjusting means 1 adjusts the timing by using a microcomputer and uses a timing standard based upon the rotation of an image formation body provided to the 1st image formation unit. Then, a rotary disk 9B is coupled with the rotating shaft of the image formation body 11 and a sensor 9A is fitted on this rotary disk 9B. A cut part 9 is formed as part of the rotary disk 9B and the sensor 9A passes by the cut part 9C, so the rotational position of the image formation body 11 is detected optically or magnetically. An elapsed time is counted on the basis of a signal obtained when the sensor passes by the cut part 9C, i.e. a drum index signal to detect image formation time points T2 and T3. Thus, a color shift is effectively and securely removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a color image recording device suitable for application to an electrophotographic color copying machine having a plurality of photosensitive drums.

[Background of the Invention] In an electrophotographic color copying machine that records color image information by forming an electrostatic latent image corresponding to color image information on a photoreceptor drum and developing this image, it is used for this purpose. The number of photosensitive drums that can be removed is usually one.

In contrast to such color image recording apparatuses, a color image recording apparatus has been proposed that uses a plurality of photosensitive drums to record color images.

In this type of color image recording device, color image information is separated into a plurality of color information, an electrostatic latent image is formed for each separated color information, and this is sequentially developed to superimpose the color images. The purpose is to obtain a desired color image. Therefore, photosensitive drums, that is, image forming bodies, are provided corresponding to the number of color information to be separated, and corresponding color separated images are supplied to each of them.

For example, color image information is divided into three complementary colors: yellow Y1, magenta Mz, and cyan cy.
In the case where the image forming body is divided into two parts for recording, three image forming bodies can be used.

FIG. 8 shows a schematic configuration of one example.

In this example, three image forming units 10-30 are provided. The first image forming unit 10 is for recording a yellow color image, the intermediate image forming unit 20 is for recording a magenta color image, and the last image forming unit 30 is for recording a cyan color image. This is for recording color images.

These image forming units 10 to 30 are arranged in the order shown in the figure with predetermined intervals maintained in the lateral direction. Therefore, this type of apparatus is called a multi-unit color image recording apparatus.

Since the image forming units 10 to 30 each have the same configuration, only the configuration of the first image forming unit 10 will be described.

In the figure, 11 indicates a drum-shaped image forming body,
A photoconductive photoreceptor surface layer made of selenium or the like is formed on its surface, so that an electrostatic image (electrostatic latent image) corresponding to an optical image can be formed.

The following members are sequentially arranged on the circumferential surface of the image forming body 11 in the direction of rotation thereof.

The surface of the image forming body 11 is charged in a negative manner by a charger 12, and the fully charged surface of the image forming body 11 is subjected to image exposure based on a yellow color separation image (the optical signal thereof is indicated by 14). .

After image exposure, the image is developed by a developing device 15. This developing device 15 is filled with a yellow toner developer. This developer adheres only to the area that has been latently imaged by the yellow color separation image, and selective development processing is performed.

The color image completely developed on the image forming body 11 is transferred onto a recording paper (transfer paper) P by a transfer device 16.

Note that 17 indicates a static eliminator and a cleaning device, and the static eliminator is composed of one or a combination of a static eliminator lamp and a corona discharger for defrosting.

The cleaning device is composed of a cleaning blade and a fur brush, and is used to remove residual toner adhering to the drum surface after the color image of the image forming member 11 has been transferred.

The recording paper P after the image transfer is conveyed by the first general feed roller 42 to the second image forming unit 20 provided at the subsequent stage.

In this second full-forming unit 20, the latent electrostatic image is developed using a color-separated image based on magenta, and is transferred onto the recording paper P that has been completely conveyed.

Similarly, the cyan electrostatic image completely formed by the third image forming unit 30 is developed and transferred onto the recording paper P.

By sequentially performing such development and transfer processing, a desired color image is recorded on the recording paper P.

Note that the developing device 2 provided in the second image forming unit 20
5 is completely filled with magenta toner developer.

This developer also adheres only to the area that has been latent imaged by the magenta color separation image, and selective development processing is performed. Therefore, the developing device 35 of the third image forming unit 30 is filled with cyan toner developer.

When the development and fixing processing based on all color separation images is completed,
A fixing process is performed by a fixing device 45 provided at the final stage, and then the recording paper P is discharged.

Note that 40 is a cassette containing recording paper P.

As the charger 12 described above, a scorotron corona discharger or the like can be used. This is because stable charging can be applied to the image forming body 11 with less influence from previous charging.

As image exposure, image exposure obtained by an optical scanning device (laser beam scanner) using laser light is used.

This is because when a laser beam scanning device is used, a small and inexpensive semiconductor laser can be used as the light source of the image recording device, and a clear color image can be recorded.

FIG. 9 shows an example of the developing device 15 used in the above.

In the figure, 51 indicates a housing, and a cylindrical sleeve 52 is rotatably housed within this housing 51. A magnetic roll having 8 N and S poles is provided within the sleeve 52 . A layer regulating piece 54 is provided on the outer peripheral surface of the sleeve 52.
is pressed against the sleeve 52, and the layer thickness of the developer adhering to the sleeve 52 is regulated to a predetermined thickness. The predetermined thickness is 1
A curvature of 0 to 500 μm refers to a predefined value.

Inside the housing 51 are roughly the first and second stirring members 5.
5.56 is provided. The developer reservoir in the developing agent reservoir 59 is moved by a first stirring member 55 that rotates counterclockwise and a first stirring member 55 that rotates counterclockwise.
The developer mixture is thoroughly stirred and mixed by a second stirring member 56 that rotates in the opposite direction to the stirring member 55 so as to overlap with each other, and the developer mixture that has been stirred and mixed is transferred to the sleeve 52 that rotates in opposite directions and magnetically. Due to the rotational conveying force of the roll 53, developer particles are adhered to and conveyed to the surface of the sleeve 52.

The electrostatic latent image formed on the image forming body 11 is developed in a non-contact manner by the developer deposited on the image forming body 11.

Note that during development, a developing bias signal that can be fully supplied from the power source 60 is applied to the sleeve 52.

The developing bias signal consists of a DC component from the power source 60 selected to have approximately the same potential as the potential of the non-exposed portion of the image forming body 11, and an AC component superimposed thereon. As a result, the sleeve 52
Only the toner T in the upper developer layer is selectively transferred to the surface of the image forming body 11, which has been formed into a latent image, and is deposited on the surface, and development processing is performed.

Note that 57 is a replenishment toner container, and 58 is a toner replenishment roller. 61 indicates a development area.

[Problems to be Solved by the Invention] Incidentally, in the multiple color image recording apparatus configured as described above, each of the image forming units 10 to 30 performs development and development with the respective color separation images superimposed. Since the image is transferred, if the transfer timings of the previous transferred image and the next transferred image do not match, the registration of the recorded image will deteriorate significantly.

That is, as shown in FIG. 8, the relative distance between the first image forming unit 10 and the second image forming unit 20 is L.
2. When the relative distance between the first image forming unit 10 and the third image forming unit 30 is L3, the image forming body 11
．． When the circumferential speed of the image forming apparatus 21 is V (m/5ee), the image forming timing of the second and third image forming units 20, 30 must be as shown in FIG.

In other words, when explaining based on the start timing of image forming processing such as development and transfer processing in the first image forming unit 10, when the image forming processing is executed in the first image forming unit 10, T2=L2/ The image forming process of the second image forming unit 20 is executed at a timing after V, and roughly from the start timing of the image forming process of the first image forming unit 10, the third image forming process is executed at a timing after T3=L3/V The image forming process of the image forming unit 30 can be completed.

Therefore, if the start timing of this image forming process is shifted even slightly, the registration will deteriorate. These values T2. It is normal for T3 to be slightly off.

In the case of a color image, if the image formation timing (transfer timing) is shifted, color shift occurs.

For example, as shown in FIG. 11, when recording the letter T in black, the second and third image forming units are placed at the same position as the yellow color separation image transferred by the first image forming unit 10. The image forming units 20 and 30 transfer the magenta and cyan color separation images, and then the entire image is recorded as one black character.

On the other hand, the second and third image formation start timings are ΔT2. If there is a shift in the image forming process for each of the eight T3 areas, the color of the image in the shifted area ΔT will not be black.

Therefore, in the multiple color image recording apparatus as described above, if the image formation start timings of the image forming units 10 to 30 do not exactly match, the registration during color overlapping will deteriorate significantly and color misregistration will occur. Occur. This leads to deterioration in the quality of recorded images.

In order to avoid such a situation, it is necessary to configure the image forming timing in each unit so that it can be adjusted independently.

However, in the color image recording apparatuses of this type that have been proposed so far, no means has been taken to independently adjust the timing of image formation.

Therefore, the present invention solves these problems, and particularly proposes a color image recording apparatus that eliminates color misregistration caused by image formation timing.

[Technical means for solving the problem] In order to solve the above-mentioned problem, in this invention, a plurality of image forming units of different colors are arranged on the recording paper conveyance path, and the recording paper is conveyed once. A color image recording apparatus that obtains a plurality of color images is characterized in that it is provided with an adjusting means for adjusting the image formation start timing of the plurality of image forming units.

A microcomputer can be used as the adjustment means.

[Function] Even if the image forming timing deviates from the design value due to part precision or variations during assembly, by adjusting the image forming timing using the adjustment means, the image forming timing of each image forming unit will match, and the image forming timing will be correct during color overlapping. Color shift can be eliminated.

[Example] Next, an example of a color image recording device according to the present invention will be described.
A case in which the present invention is applied to the multi-layer color image recording apparatus as described above will be described in detail with reference to FIG. 1 and subsequent figures. Therefore, a detailed explanation of the multiple color image recording apparatus, which is the premise of this invention, will be omitted.

FIG. 1 shows an example of an image forming timing adjusting means 1 that can be used in a color image recording apparatus according to the present invention.

In this example, a microcomputer is used to adjust the timing, and the timing reference is the rotation of the image forming body 11 provided in the first image forming unit 10.

Therefore, as shown in FIG. 2, a rotating disk 9B is connected to the rotating shaft of the image forming body 11, and a sensor 9A as shown is attached to this rotating disk 9B. Rotating disk 9B
A notch 9C as shown in the third factor is formed in a part of the sensor 9A, and when the sensor 9A crosses this notch 9C, the rotational position of the rotating disk 9B, and therefore the image forming body 11, is optically or Magnetically detected.

If the elapsed time is counted based on No. 18, that is, the drum index signal obtained by crossing the notch 9C in this way, image forming timing T2.
T3 can be detected.

This means that the drum index signal can also be used as a timing adjustment signal.

FIG. 1 shows an example of an adjusting means 1 using the drum index signal described above, which includes second and third image forming timing adjusting sections LM and IC.

Each timing adjustment section IM, IC is composed of a counter 2.5 and a power supply control circuit 3.6, and a clock of a predetermined frequency is supplied from a clock generator 8 to the clock terminal of each counter 2.5, and the clock is cleared. A drum index signal detected by the sensor 9A is supplied to one terminal.

Each of the counters 2 and 5 is provided with a preset terminal, and a preset value P2. It is designed so that a count output can be obtained when counting up to P3.

Preset value P2. P3 is the above-mentioned period T2. Although it can be set to a value corresponding to T3, this preset value P2. Since the timing at which the counter output is obtained differs by adjusting P3, the image forming timing can be finely adjusted individually based on this.

The power supply control circuit 3.6 is controlled by the counter output. That is, the power supply control signals SM and SC shown in FIG. 4 are generated at the timing when the counter output is obtained, and thereby the actual bias power supply (60 in FIG. 9) is controlled to be in the on state for a predetermined period ( (See Figure 4).

FIG. 5 shows an example of a control system for realizing adjustment of image forming timing. In this example, fine adjustment is attempted to be achieved by a microcomputer as described above.

In the figure, 81 is a CPU, 82 is a ROM in which a control program is stored, and 83 is a RAM for storing various data. Data for timing adjustment keyed in from the operation/display unit 90 provided in the device is taken into the CPU 81 via the I10 port 85 and predetermined data processing is executed, and the data after data processing is sent to the I10 port 86. The information is displayed on a display section provided in the operation/display section 90 via the display section 90.

FIG. 7 shows an example of the arrangement of the operation/display section 90.
92 is a copy switch, and 92 is a numeric keypad.The number of copies set here can be digitally displayed on a display section 93. 94 is a program key, and 95 is a switch for switching between magenta and cyan.

The program key 94 is a key used when adjusting the timing, and the changeover switch 95 is a switch for selecting which image forming timing is to be adjusted.

Note that 96 is a copy density selection switch, and the selected copy density is displayed on the display section 97 in stages.

Now, an example of a control program for timing adjustment as described above will be explained in detail with reference to FIG.

When the control program is started, if the operation of the program key (P key) is checked (step 101), then the operation status of the selection switch 95 can be determined. Each time the selection switch is operated, the magenta adjustment mode and the cyan adjustment mode are alternately selected (step 102). This mode determination is made by checking the presence or absence of a magenta adjustment mode flag to determine whether the mode is magenta adjustment mode or cyan adjustment mode.

As a result of the determination, if it is the magenta adjustment mode, the preset value P2 is entered from the numeric keypad 92, thereby changing the image forming timing and displaying this preset value (steps 103 to 105).

Next, the operating state of the copy switch 91 could be determined,
When operated, the preset value P2 input immediately before is updated as the image formation start timing (step 10).
6,107).

Similarly, when the cyan adjustment mode is fully selected in step 102, the image formation start timing is changed to the keyed-in new preset value P3, and at the same time, that value is fully displayed (steps 111 to 113). Then, the image formation start timing is updated in accordance with this changed preset value P3.

Therefore, when a color shift as shown in Fig. 11 occurs, determine which color is shifted by how much from the color shift state of the recorded image, and use the results to change the necessary preset values using the procedure described above. Just do it.

In the above description, a microcomputer is used to adjust the timing of starting image formation, but normal preset processing that does not use a microcomputer may be used.

In general, in the above description, the keys on the operation/display section 90 are also used as timing adjustment keys, but a dedicated adjustment key may also be provided. In that case, the adjustment key may be provided at any location. For example, when the front door for copy adjustment of the apparatus is opened, it may be provided on a part of the adjustment panel, or it may be provided on a part of a control board on which circuit elements for a microcomputer are arranged.

[Effects of the Invention] As explained above, according to the present invention, since the adjustment means that can adjust the timing of starting image formation in the image forming unit is provided, parts mounting may be performed due to factors such as accuracy or assembly variations. The number marked is distance L2. Even if L3 or drum circumferential speed V does not match the designed values, the occurrence of color misregistration can be effectively and reliably eliminated.

Therefore, according to the present invention, it is possible to easily obtain a recorded image with clear image quality and no color shift.

For this reason, the present invention is extremely suitable for application to a multi-layer color image recording apparatus as shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of the timing adjustment means used in the color image recording device according to the present invention, FIG. 2 is a plan view showing the relationship between the image forming body and the index sensor, and FIG. 3 is a side view thereof. Figure 4 is a waveform diagram for explaining timing adjustment, Figure 5 is a system diagram of a control system for timing adjustment, Figure 6 is an example of the control flowchart, and Figure 7 is an operation/display. 8 is a configuration diagram showing an example of a multi-unit color image recording device, FIG. 9 is a sectional view of a developing device used in this device, FIG. 10 is a diagram showing image formation timing, and FIG. FIG. 11 is an explanatory diagram of color shift. 10 to 30... Image forming unit 11.21.31... Photosensitive drum serving as an image forming member 15.25.35... Developing device P... Recording body 1... Adjusting means 1M, IC. ...Adjustment unit 2.5...Counter 3.6...Power control circuit 9A...Index sensor SM, SC...Power control signal Patent applicant Konishiroku Photo Industry Co., Ltd. Figure 1 M 2 Figure A: Figure 3: 4vA Figure 9: Theory

Claims (2)

[Claims] (1) In a color image recording device in which a plurality of image forming units of different colors are arranged on a recording paper conveyance path and a plurality of color images are obtained by conveying the recording paper once, image formation by the plurality of image forming units is performed. A color image recording device comprising an adjusting means for adjusting start timing. (2) The color image recording apparatus according to claim 1, wherein a microcomputer is used as the adjustment means.