JPH0882985A - Color image forming device - Google Patents

Abstract

PURPOSE: To adjust timing for exposing an image in accordance with circumferential speed of an image forming body and the fluctuation and the change of the position of an image exposing means so as to accurately superpose a toner images in a color image forming device on each other in which plural image exposing means are provided in the vicinity of the image forming body and the toner images are superposed. CONSTITUTION: A signal from a temperature sensor detecting the temperature of a photoreceptor 10 and a supporting member 20 is inputted to a CPU, and the rotating speed of the photoreceptor 10 is controlled by the controlling program of a ROM and a clock signal based on the table of a photoreceptor speed on temperature information, and at the same time, the respective exposing timings of respective LED arrays constituting the respective image exposing means, that is, the LEDs 1 to 4 are adjusted in accordance with an interval of mutual image exposing positions by a reading timing controlling circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic system in which a plurality of image exposing means and developing means are arranged on the peripheral surface of an image forming body so that toner images are superposed during one rotation of the image forming body. The present invention relates to a color image forming apparatus.

[0002]

2. Description of the Related Art As a method for forming a multicolor image, a monochromatic toner image formed on each photoconductor is intermediately transferred by equipping the photoconductor with the same number of images as necessary, a charger and a developing device. A device that creates a color image by superimposing it on an image (A)
A device (B) for forming a color image by repeating charging, image exposure and development for each color by rotating one photosensitive member a plurality of times, or charging and image exposure for each color within one rotation of one photosensitive member. In addition, an apparatus (C) and the like for forming a color image by sequentially performing development are known.

However, the above-mentioned device (A) has a drawback that the volume of the device is increased because a plurality of photoconductors and intermediate transfer members are required, while the device (B) has a charging means, an image exposing means and a photoconductor. However, there is a restriction that the size of the formed image is limited to the surface area of the photoreceptor or less, though the volume is reduced.

Although the device (C) enables high-speed image formation, it is necessary to dispose a plurality of sets of a charger, an image exposing means and a developing device within one circumference of the photosensitive member. A function and performance capable of superimposing the toner images of the respective colors formed by the image exposing means and the developing device with high accuracy are required.

[0005]

The accuracy of the superposition of a plurality of toner images depends mainly on the accuracy of the image exposure timing on the image forming body when forming the respective toner images, but the image exposure timing itself. Also varies depending on the change in the peripheral speed of the image forming body, and due to the inclination and non-linearity of the LED array used as the exposure optical system, the overlay is incomplete and local so-called color misregistration occurs, resulting in high quality. I can't get a color image.

As a result of solving these problems and improving the present invention, the timing of image exposure is individually adjusted for a plurality of image exposure means in accordance with the change in the peripheral speed of the image forming body and the positional relationship of the image exposure means. It is an object of the present invention to provide a color image forming apparatus capable of forming a high quality color image by automatically adjusting the toner images, thereby accurately superimposing the toner images of the respective colors.

[0007]

The above object is to provide a plurality of charging means, image exposing means, and developing means in the vicinity of the image forming body, and repeat charging, image exposing and developing to form an image on the image forming body. In a color image forming apparatus that performs batch transfer on a transfer material after forming toner images in a superposed manner, the plurality of image exposure units sets the distance between image exposure positions to be substantially the same,
A color image forming apparatus (first invention) characterized in that the timing of image exposure at each exposure position is adjusted by changing the peripheral speed of the image forming body, a plurality of charging means near the image forming body, and image exposure. Means and a developing means, the toner image is repeatedly formed on the image forming body by repeating charging, image exposure and development, and then the plurality of images are formed on the transfer material by batch transfer. A color image forming apparatus (second invention) and a drum shape, wherein the exposure means adjusts the image exposure timing at each exposure position proportionally from the initial setting value according to the distance between the image exposure positions. A plurality of charging means, image exposing means, and developing means are disposed in the vicinity of the image forming body, and charging, image exposing and developing are repeated to form a toner image on the image forming body in a superimposed manner, and then the transfer material is formed. Performing batch transfer In the image forming apparatus, the angular velocity of the image forming body, the image front end by the image exposing means, and the timing of image exposure in the main scanning direction are controlled on the basis of a common reference clock (first color image forming apparatus. 3 invention).

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of each embodiment of the present invention, the structure of a color image forming apparatus common to each invention will be described with reference to FIGS. 1, 2 and 3.

Reference numeral 10 denotes a drum-shaped image forming body, that is, a photosensitive drum, which is a transparent conductive layer on the outer periphery of a cylindrical substrate formed of a transparent member such as optical glass or transparent acrylic resin.
An organic photosensitive layer (OPC) is applied.

A flange 10A at one end of the photosensitive drum 10 has a guide pin 30 provided in a cartridge 30 described later.
The flange 10B at the other end is supported by P, and the flange 10B at the other end is fitted onto a plurality of guide rollers 40R provided on the substrate 40 of the apparatus main body to mesh the outer gear 10G with the drive gear 40G. Rotated clockwise with the layers grounded.

Reference numeral 11 denotes a scorotron charger, which is a photosensitive drum 10.
The above-mentioned organic photoconductor layer is charged by a grid held at a predetermined potential and corona discharge by a discharge wire to give a uniform potential to the photoconductor drum 10.

Reference numeral 12 denotes L arranged in the axial direction of the photosensitive drum 10.
In an exposure optical system composed of an ED and a self-occurring lens, image signals of respective colors read by a separate image reading device are sequentially taken out from a memory and inputted to the respective exposure optical systems 12 as electric signals. It

Each of the exposure optical systems 12 is mounted on a columnar support member 20 which is fixed to a substrate 40 of the main body of the apparatus by using a guide pin 40P1 as a guide, and the photoconductor drum 10 is mounted.
Is housed inside the base body of.

Numerals 13Y to 13K are developing devices for accommodating each of yellow (Y), magenta (M), cyan (C) and K (black) developers, each having a predetermined gap with respect to the peripheral surface of the photosensitive drum 10. Developing sleeve 130 that rotates in the same direction while maintaining
It has.

Each of the developing devices is in a non-contact state by applying a developing bias voltage to the electrostatic latent image formed on the photosensitive drum 10 formed by the charging by the charging device 11 and the image exposure by the exposure optical system 12 described above. Reverse development with.

Next, the process of the color image forming apparatus in this apparatus will be described.

The original image is temporarily stored in an image reading device, which is separate from the present device, as an image read by the image pickup device or an image edited by a computer as an image signal for each color of Y, M, C and K. Are stored and stored in.

When the photoconductor drive motor is started by the start of image recording, the drive gear 40G is rotated to rotate the photoconductor drum 10 in the clockwise direction, and at the same time, the photoconductor is driven by the charging action of the charger 11 (Y). Application of electric potential to the drum 10 is started.

After the photosensitive drum 10 is applied with an electric potential,
In the exposure optical system 12 (Y), the exposure by the electric signal corresponding to the first color signal, that is, the yellow (Y) image signal is started, and the yellow (Y) of the original image is formed on the photosensitive layer on the surface by the rotational scanning of the drum. ) Form an electrostatic latent image corresponding to the image.

The latent image is reversely developed by the developing device 13 (Y) with the developer on the developing sleeve in a non-contact state, and a yellow (Y) toner image is formed in accordance with the rotation of the photosensitive drum 10.

Then, the photoconductor drum 10 is further given a potential on the yellow (Y) toner image by the charging action of the charger 11 (M), and the second color signal of the exposure optical system 12 (M), that is, Exposure with an electric signal corresponding to the magenta (M) image signal is performed, and non-contact reversal development by the developing device 13 (M) causes a magenta (M) toner image on the yellow (Y) toner image. Will be sequentially stacked.

By the same process, a cyan (C) toner image corresponding to the third color signal is further generated by the charging device 11 (C), the exposure optical system 12 (C) and the developing device 13 (C), and the charging device. 11 (K), exposure optical system 12 (K) and developing device 13
By (K), a black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed, and a color toner image is formed on the peripheral surface of the photosensitive drum 10 within one rotation.

Photoreceptor drum 10 by each of these exposure optical systems
The exposure of the organic photosensitive layer is conducted from the inside of the drum through the above-mentioned transparent substrate. Therefore, the exposure of the image corresponding to the second, third, and fourth color signals is performed without any influence of the toner image previously formed, and is equivalent to that of the image corresponding to the first color signal. It is possible to form an electrostatic latent image. The stabilization of the temperature inside the photosensitive drum 10 and the prevention of the temperature rise due to the heat generation of each exposure optical system 12 use a material having good thermal conductivity for the supporting member 20, and use a heater 201 when the temperature is low, When the temperature is high, it can be suppressed to a level without any trouble by taking measures such as radiating heat to the outside through the heat pipe 202. Further, during the developing action by each developing device, a developing bias in which direct current or further alternating current is applied to the developing sleeve 10 is applied,
Jumping development is performed by a one-component or two-component developer housed in the developing device, and non-contact reversal development is performed on the photosensitive drum 10 whose grounding the transparent conductive layer.

Thus, the color toner image formed on the peripheral surface of the photosensitive drum 10 is transferred to the transfer paper which is conveyed from the paper feed cassette 15 in the transfer device 14A and is fed in synchronization by the driving of the timing roller 16. It

The transfer paper on which the toner image has been transferred is a static eliminator.
In 14B, the charge is removed and the toner is separated from the peripheral surface of the drum. After the toner is fused in the fixing device 17, the toner is discharged via the paper discharge roller 18 onto the tray above the device.

On the other hand, the photosensitive drum 10 from which the transfer paper has been separated removes and cleans the residual toner in the cleaning device 19 to continue the formation of the toner image of the original image, or temporarily stops the toner image of the new original image. Formation.

The photoconductor drum 10, the charging devices 11, the developing devices 13, and the cleaning device 19 are housed in a cartridge 30 and integrated with each other, except for a supporting member 20 having an exposure optical system 12. It is configured to be removable inside.

That is, the cartridge 30 is housed in a frame 50 shown in FIG.

The structure in which the supporting member 20 is left at the time of attachment / detachment is a heater.
201, heat pipe 202, lead wire 20 for operating the LED
It has a feature that the optical system 12 and the optical system 12 can be fixed to the supporting member 20 despite the rotation of the photoconductor and the attachment / detachment of the photoconductor. It can also be used to determine the axis of the photosensitive drum 10 as described below.

When mounted, the gantry 50 comprises a side plate 50A and a pair of support pedestals 50B. The cartridge 30 is placed and slid horizontally along the guide rails 51 inside the main body in a locked state.

The mount 50 is a guide pin that supports the photosensitive drum 10 in the cartridge 30 when it is inserted into the apparatus.
30P is engaged with the support member 20 for mounting the exposure optical system 12 described above, and the flange 10B is provided before and after the support member 20 for mounting the substrate 40.
After being externally fitted to the side guide roller 40R, the side plate 50A is tightly fixed to the abutting portion 53 of the apparatus main body by using the tightening screw 52 as a fixing means. As a result, the axial center and the axial center position of the photosensitive drum 10 with respect to the image forming portion are determined.

When the pedestal 50 is pulled out from the inside of the apparatus at the time of dismounting, the photoconductor drum 10 causes the exposure optical system 12 described above.
The slide is stopped at a position separated from the support member 20 to which the guide is attached, and the guide rail 51 supports the slide rail.

The photosensitive drum 10 which is disengaged from the guide roller 40R provided on the substrate 40 by pulling out the mount 50.
The flange 10B is supported by several folding portions 30A formed integrally with the cartridge 30 and maintains the same axial center position as that at the time of insertion. Therefore, when the frame 50 is inserted again, the flange 10B is easily fitted on the guide roller 40R to set the photosensitive drum 10 at the normal axial position.

(Embodiment 1) An embodiment of the first invention of the present invention will be described with reference to FIGS.

The above-mentioned apparatus is provided with the exposure optical systems 12 (Y), 12
(M), 12 (C), and 12 (K) are set to have substantially the same positional intervals, and can cope with the variation of the length of the peripheral surface of the photosensitive drum 10 and the distance between the exposure optical systems 12. Then photoconductor drum
By controlling the peripheral speed of 10, the images are accurately superimposed at a predetermined image exposure timing.

The variation amount (ΔL ₁ ) with the temperature change of the length of the peripheral surface of the photosensitive drum 10 and the substantially equal distance (L ₁ ) between the exposure optical systems 12 on the photosensitive drum 10 depends on the temperature sensor. It is indirectly detected by the temperature difference from the reference temperature, and further, regarding the photosensitive drum 10, the change amount (Δ) of the length with respect to the reference length (L ₀ ) of the peripheral surface of the photosensitive drum 10 by replacement.
L ₀ ) is indicated by, for example, a label showing the outer diameter dimension.

In FIG. 4, the exposure positions of the image exposing means at equal intervals with respect to the photoconductor drum 10 are unchanged, but color misregistration caused by a change in environmental temperature is eliminated, and the temperature of the photoconductor drum 10 is detected. 1 shows a system for detecting a variation amount of a distance between each exposure optical system 12 on a peripheral surface and controlling a peripheral speed of a photosensitive drum 10 based on the information.

Photosensitive drum detected by temperature sensor
The temperature data (temperature difference from the reference temperature) of the support member 20 that supports 10 and each exposure optical system 12 is converted into a digital signal and input to the CPU, ROM and programmable oscillator.

The digital signal relating to the temperature is the CPU
A clock signal having a predetermined frequency is generated by the programmable oscillator based on the table of the peripheral speed of the photoconductor corresponding to the temperature data which is the control program stored in the ROM.

The clock signal is sent to a PLL control type drive circuit to control the number of rotations of the motor to adjust the peripheral speed of the photoconductor drum 10, and thereby the deviation of the image exposure timing due to the temperature change. Resolve. That is, when the reference rotation speed of the photosensitive drum 10 is u and the temperature difference from the reference temperature is t, the rotation peripheral speed obtained by the table is represented by u × (1 + ct).

Here, c is a value approximate to the experimentally obtained linear expansion coefficient.

On the other hand, FIG. 5 shows a system for controlling the rotational peripheral speed of the photoconductor drum 10 based on the information on the outer diameter or the length of the peripheral surface of the photoconductor drum 10 changed by the replacement with a new one. is there.

The photoconductor drum 10 has information about the outer diameter or the outer circumference displayed on the outside by a bar code or the like on a label. When the photoconductor drum is replaced, the information is read by the photoconductor information reading device. It is directly input to the CPU, ROM and programmable oscillator as a digital signal.

The read signal is read by the CPU.
A programmable oscillator is caused to generate a clock signal of a predetermined frequency based on a photosensitive member speed table corresponding to the outer diameter of the photosensitive member or the length of the peripheral surface of the control program stored in the OM.

Next, the clock signal is sent to a drive circuit of the PLL control system to control the rotation speed of the motor to adjust the peripheral speed of the photoconductor drum 10, and thereby the image exposure caused by the replacement of the photoconductor drum. Eliminate the timing gap.

That is, the reference rotational speed of the photosensitive drum 10 is u
When the reference outer peripheral length of the photosensitive drum 10 is L _0, and when the photosensitive drum is replaced with a photosensitive drum having an outer peripheral length of (L ₀ + ΔL ₀ ), the rotational peripheral speed obtained by the table is
It is represented by u × (1 + ΔL ₀ / L ₀ ), which controls the rotational peripheral speed and prevents color misregistration.

In the above control of the peripheral speed of the photosensitive drum, the speed is not controlled based on the temperature detection of the environmental conditions or the dimension information of the photosensitive drum to be replaced, but the image forming output is judged. It is also possible to do so. For example, a resist pattern is formed on the image forming body with various toners, and the resist amount (deviation amount of each color pattern) is detected, or the resist pattern on the transfer paper is visually detected to determine the shape of the separately prepared resist pattern and the photosensitivity. It is also possible to change and set to the most suitable peripheral speed without color shift by selecting the peripheral speed value of the photosensitive drum or a specific value corresponding to it from the comparison table with the peripheral speed of the body drum. is there.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. 6 to 11.

The above-mentioned apparatus is provided with the exposure optical systems 12 (Y), 12
Image exposure by proportionally adjusting and controlling the light emission timing of the LED array, which is the light source of each exposure optical system 12, according to the positional intervals of (M), 12 (C), and 12 (K) from the initial setting value. Is adjusted so that the toner images of the respective colors described above are accurately superimposed.

Variation in the length of the peripheral surface of the photosensitive drum 10 in use and the distance (L ₁ , L ₂ , L ₃ ) between each LED array of each exposure optical system 12 on the photosensitive drum 10 with temperature change. The amounts (ΔL ₁ , ΔL ₂ , ΔL ₃ ) are indirectly detected by the temperature difference from the reference temperature by the temperature sensor, and serve as a reference for the length of the peripheral surface when the photosensitive drum 10 is replaced with a new one. variation with respect to the length (L ₀₎ (ΔL ₀₎ is indicated by the label or the like to display the outer diameter.

FIG. 6 detects the amount of variation in the distance between the exposure optical systems 12 on the peripheral surface of the photosensitive drum 10 in use by detecting the temperature, and based on the information, the LED array of each exposure optical system 12 is detected. 2 shows a system for controlling the light emission timing of.

The temperature data of the photosensitive drum 10 and the support member 20 supporting the exposure optical system 12 detected by the temperature sensor are converted into digital signals and input to the CPU, ROM and programmable oscillator.

The digital signal relating to the temperature is the CPU
The programmable oscillator is caused to generate a clock signal of a predetermined frequency based on a table of the peripheral speeds of the photoconductor corresponding to the temperature of the control program stored in the ROM.

The clock signal is sent to a PLL control type drive circuit to control the rotation speed of the motor to adjust the peripheral speed of the photosensitive drum 10 to a specified speed.

In the present invention, the digital signal is also input to the read timing control circuit as a timing control signal for image exposure and used for read timing control of the pixels stored in the page memory. In the present invention, the timing of image exposure at each exposure position is proportionally adjusted from the initial setting value according to the interval between the image exposure positions of the image exposure means, which will be specifically described.

The page memory is composed of, for example, 5000 pixels in the main scanning direction and 6000 lines in the sub-scanning direction, and the LEDs of each exposure optical system 12 for the photosensitive member.
If the array is arranged at 1000 pixel intervals at a detection temperature of 20 ° C, the above-mentioned support member will be
20 expands, the interval between each LED array expands and the number of pixels between them increases, and the exposure optical systems 12 (Y), 12 (M), 12
LED arrays of (C) and 12 (K)
LE as 1, LED2, LED3 and LED4
The distance between LED2, LED3, and LED4 with respect to D1 is the number of pixels shown in FIG. 8 (1000 + ΔL ₁ , 2000 + ΔL ₂ , 3000
Enlarged to correspond to + ΔL ₃ ).

As shown in FIG. 9, when reading the first color (Y) of the image data formed by the page memory, the read data is temporarily buffered without being controlled by the read timing regardless of whether the detected temperature is above or below. 1
Then, writing to the photosensitive surface is started according to the initial setting value by the light emission of the LED 1.

Next, in the second color (M) reading, when the detected temperature is 20 ° C. which is the reference temperature, the first color (Y) reading reaches 1000 lines as shown in FIG. 10A. Reading is started under the control of the reading timing so as to be synchronized. On the other hand, when the detected temperature is 20 ° C. or more, writing to the photosensitive surface of the first color (Y) is (1000 + ΔL ₁ ) as shown in FIG. The reading of the second color (M) is started under the control of the reading timing so as to be synchronized with reaching the line. The read data of the second color (M) is temporarily stored in the write buffer 2 and
The light emission of 2 starts writing on the photosensitive surface.

Further, in the reading of the third color (C), when the detected temperature is 20 ° C., the writing of the first color (Y) described above is performed on 2000 lines as shown in FIG. 11A, and accordingly, the second color (M) is read. The reading of the third color (C) is started under the control of the read timing so as to be synchronized with the writing of 1000 lines, and when the detected temperature is 20 ° C or higher, as shown in Fig. 11 (b). Writing the first color (Y) is (20
The reading of the third color (C) is started under the control of the write timing so that the writing of the second color (M) to the (00 + ΔL ₂ ) line and thus the writing of the second color (M) reaches the (1000 + ΔL ₂ −ΔL ₁ ) line. Are temporarily stored in the write buffer 3 and the writing on the photosensitive surface is started by the light emission of the LED 3.

In the writing of the image data of the fourth color (K), the reading process is started by different reading timings according to the control program selected by the temperature difference between the detected temperature and the reference temperature by the same process, and the writing buffer 4 is read. Then, writing is started by the light emission of the LED 4.

In this way, the image exposure means proportionally adjusts the image exposure timing according to the distance between the image exposure positions and the temperature of the support member 20 for supporting the photosensitive drum 10 and the exposure optical system 12. Automatically adjusts to changes,
Accurate superposition of the toner images of the respective colors realizes formation of a color image having excellent color balance.

When the detected temperature is 20 ° C. or lower, the above ΔL
The signs of ₁ , ΔL ₂ and ΔL ₃ are reversed and the write timing is controlled in the same manner as described above.

On the other hand, FIG. 7 shows a system for controlling the rotational speed of the photoconductor drum 10 and the timing of image exposure based on the length of the peripheral surface of the photoconductor drum 10 changed by the replacement with a new one. The length of the peripheral surface of the photoconductor drum 10 is automatically or manually input by a reading device provided in the color image forming apparatus for information such as the outer diameter dimension displayed on the label, and according to a control program selected based on this. By the same process as in the case of FIG. 6, the timing of image exposure is controlled proportionally from the initial setting value in a form corresponding to the interval between image exposure positions.

The image exposure timing control described above controls the image exposure timing based on the environmental temperature detection and the dimension information of the photosensitive drum to be replaced. It is also possible to do this. For example, a resist pattern is formed with various toners on the image forming body, and the resist amount (deviation amount of each color pattern) is detected, or the resist pattern on the transfer paper is visually detected, and the shape of the separately prepared resist pattern is imaged. It is also possible to change or set the image exposure timing by selecting an image exposure timing value or a specific value to be set in this from a comparison table with the exposure timing and inputting this value.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIGS.

In the color image forming apparatus of the present invention,
The photosensitive drum 10 is driven and rotated by a motor whose rotational speed is controlled by a pulse signal generated by a clock while maintaining a constant angular velocity, and image exposure in the image front end and main scanning direction by image exposure means. As for the timing of, the pulse signal generated by the same clock is operated so that a certain time relationship is maintained.

Therefore, the photosensitive drum 10 is a light source of each exposure optical system 12 even if the outer diameter thereof changes to D1 to D2 as shown in FIG. 12 due to a temperature change during use or a replacement with a new one. Distance between LED arrays L ₁ and L ₁ + ΔL ₁
Difference [Delta] L ₁ is only to slightly change the print density, does not require adjustment without change for registration timings That toner image of each color image exposure.

FIG. 13 shows the driving / driving based on the reference clock.
In the block diagram showing the controlled state, the pulse signal generated by the reference clock drives and controls the pulse motor that rotates the photosensitive drum 10. With respect to the image exposure of the LEDs 1 to 4 as well, driving and control of the timing of image exposure start and image exposure in the main scanning direction are performed based on the pulse signal generated by the same reference clock. That is, the image information of the read original is image-processed and temporarily stored in the page memory, and then the image information of each color is transferred to the write buffers 1 to 4 by the read timing control circuit. The image information transferred to each write buffer is transferred to the main scanning delay circuit for each line of image information for one line in the main scanning direction or for each line of image information for a plurality of lines in the main scanning direction for driving / control by the reference clock. The exposure start of the LED, which is the exposure means of the exposure optical system, and the drive / control of the exposure timing in the main scanning direction are performed below according to a digitized writing program that is set in advance and incorporated in the ROM or the like.

Further, in the color image forming apparatus capable of adjusting the writing position (diagonal) of the image on the transfer paper, the tip of the image and the main scanning direction can be adjusted in accordance with the above-mentioned adjustment operation. The image exposure timing is configured to be changed based on the reference clock, so that the toner image is not displaced even if the environmental temperature fluctuates.

Although the color image forming apparatus described in the above embodiments is provided with the exposure optical system inside the photosensitive drum, the present invention is not limited to this, and the exposure optical system is the photosensitive drum. It may be provided on the peripheral portion (outside) of the. Further, the image forming body of the present invention may be a photoreceptor belt formed by forming a photoreceptor on a belt-shaped substrate instead of the photoreceptor drum. In this case as well, regardless of whether the image exposure is performed from the inner side of the photoreceptor belt or the outer side, a plurality of sets of charging means, image exposing means, and developing means are provided in the vicinity of the image forming body. The present invention includes a color image forming apparatus in which a toner image is superposed on the image forming body by forming the above.

[0071]

According to the present invention, it becomes possible to automatically control and adjust the timing of image exposure in response to fluctuations and changes in the peripheral speed of the image forming body and the distance between the image exposing means. As a result, it is possible to provide a color image forming apparatus capable of forming a high-quality image with high accuracy in superimposing toner images.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus of the present invention.

FIG. 2 is a cross-sectional configuration diagram of an image forming unit.

FIG. 3 is a perspective view showing a detachable form of an image forming unit.

FIG. 4 is an explanatory diagram showing a resist management method according to a temperature change of an image forming body.

FIG. 5 is an explanatory diagram showing a resist management system associated with conversion of an image forming body.

FIG. 6 is an explanatory diagram showing a resist management system of an exposure optical system according to a temperature change.

FIG. 7 is an explanatory diagram showing a method of resist management of the exposure optical system accompanying replacement.

FIG. 8 is an explanatory diagram showing a change in the interval of the exposure optical system.

FIG. 9 is an explanatory diagram showing the read timing of the first color (Y).

FIG. 10 is an explanatory diagram showing the read timing of the second color (M).

FIG. 11 is an explanatory diagram showing the read timing of the third color (C).

FIG. 12 is an explanatory diagram showing changes in the length of the peripheral surface of the photoconductor due to changes in temperature.

FIG. 13 is an explanatory diagram showing drive control of a rotation speed of an image forming body and image exposure timing of an exposure optical system by a reference clock.

[Explanation of symbols]

 10 Photoconductor drum 11 Charger 12 Exposure optical system 13 Developer 14A Transfer device 14B Static eliminator 15 Paper feed cassette 16 Timing roller 17 Fixing device 18 Paper ejection roller 19 Cleaning device 20 Supporting member 30 Cartridge 40 Substrate 50 Frame LED1-LED4 Light source

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03G 21/14

Claims (11)

[Claims] 1. A plurality of charging means, image exposing means, and developing means are arranged in the vicinity of the image forming body, and after charging, image exposing and developing are repeated, a toner image is formed on the image forming body by superposition. In a color image forming apparatus that performs batch transfer onto a transfer material, the plurality of image exposure units set the image exposure positions at substantially the same intervals, and the image exposure timing at each exposure position is set to the image forming body. A color image forming apparatus, wherein the color image forming apparatus is adjusted by changing the peripheral speed of the. 2. The color image forming apparatus according to claim 1, wherein each exposure position of the plurality of image exposure units is unchanged. 3. The color image forming apparatus according to claim 1, wherein the change of the image exposure timing is performed according to the temperature change of the image forming body or the support of the image exposing means. 4. The color image forming apparatus according to claim 1, wherein the change of the image exposure timing is performed according to the conversion of the image forming body. 5. The color image forming apparatus according to claim 1, wherein the change of the image exposure timing is performed by determining the image forming output. 6. A plurality of charging means, image exposing means, and developing means are arranged in the vicinity of the image forming body, and after charging, image exposing and developing are repeated, a toner image is formed on the image forming body by superposition. In a color image forming apparatus that performs batch transfer on a transfer material, the plurality of image exposure units adjust the image exposure timing at each exposure position proportionally from the initial setting value according to the interval between the image exposure positions. A color image forming apparatus characterized by the above. 7. The color image forming apparatus according to claim 6, wherein the change of the image exposure timing is performed according to the temperature change of the image forming body or the support of the image exposing means. 8. The color image forming apparatus according to claim 6, wherein the change of the image exposure timing is performed according to the conversion of the image forming body. 9. The change of the image exposure timing is performed by judging the output of the image forming body.
The described color image forming apparatus. 10. A plurality of charging means, image exposing means, and developing means are provided in the vicinity of a drum-shaped image forming body, and a toner image is superimposed on the image forming body by repeating charging, image exposure and development. In a color image forming apparatus that performs batch transfer onto a transfer material after being formed, the angular velocity of the image forming body, the image front end of the image exposing unit, and the timing of image exposure in the main scanning direction are controlled based on a common reference clock. A color image forming apparatus characterized by the above. 11. The color image forming apparatus according to claim 10, wherein the timings of image front end and image exposure in the main scanning direction by each of the image exposure means can be changed based on the reference clock.