JPH08171251A - Color image forming device - Google Patents

Abstract

PURPOSE: To obtain the well-balanced rotation of a photoreceptor drum by disposing an image exposure means in a supporting member provided inside an image forming body and providing an electrifier or a cleaning device in the supporting member provided outside the image forming body. CONSTITUTION: Exposure optical systems 12Y, 12M, 12C and 12K and three guide rollers 22r are disposed in the 1st columnar supporting member 20. Scorotron electrifiers 11Y, 11M, 11C and 11K and the cleaning device 19 are attached to the inside of the cylindrical part of the 2nd supporting member 50. The 2nd supporting member 50 to which the electrifiers 11Y, 11M, 11C and 11K are attached is fitted in the end of the 1st supporting member 20 in a state where the center of the supporting shaft of the photoreceptor drum 10, that is, the center of the drum 10, the center of the 1st supporting member 20 and the center of the cylindrical part of the 2nd supporting member 50 are superposed. In the case of inspection, they are attached/detached and replaced in a state where a screw is removed and the supporting member is released from a supporting shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device in which a plurality of charging means, image exposing means and developing means are arranged on the peripheral surface of an image forming body to superpose toner images during one rotation of the image forming body. The present invention relates to a photographic 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 of the photoconductors is transferred by using a photoconductor, a charging device, a developing device and the like as many images as necessary. A color image forming apparatus that forms a color image by superimposing the same on one or more of the above, and one photosensitive member is rotated a plurality of times to charge each color,
A color image forming apparatus that forms a color image by repeating image exposure and development, or a color image formation that forms a color image by sequentially performing charging, image exposure, and development for each color within one rotation of one photosensitive member. Devices and the like are known.

However, in each of the above-mentioned image forming apparatuses, an image is provided with the same number of photoconductors, charging devices, and developing devices as the required colors, and the monochromatic toner image formed on each photoconductor is superposed on the transfer body or the like. A color image forming apparatus for producing a color image has a drawback that the volume of the apparatus becomes large because it requires the conveyance of a plurality of photoconductors or transfer bodies. On the other hand, one photoconductor is rotated a plurality of times to charge each color, A color image forming apparatus that forms a color image by repeating image exposure and development has only one charging unit, image exposure unit, and photoconductor, so that the volume can be reduced, but the size of the image formed is photosensitive. There is a restriction that it is limited to the surface area of the body or less.

Further, although a color image forming apparatus which forms a color image by sequentially performing charging, image exposure and development for each color within one rotation of one photoconductor is capable of high speed image formation, Since it is necessary to dispose a plurality of sets of a charging device, an image exposing unit and a developing device within one circumference, there is a risk that the toner leaking from the developing device in the vicinity of the optical system for performing the image exposure will be contaminated and the image quality will be impaired. Since it is necessary to increase the distance between the image exposure means and the developing device in order to avoid it, there is a contradiction that the diameter of the photoconductor is inevitably increased and the device is enlarged. For the purpose of avoiding this drawback, the substrate of the image forming body is formed of a transparent material, and a plurality of image exposing means are housed therein, and the image is exposed through the substrate to the photosensitive layer formed on the outer periphery thereof. The device of the form is, for example,
It is proposed by the Japanese Patent Publication No. 5-307307.

[0005]

As is well known, the image forming body is driven and rotated during image formation, and it is usually replaced from the main body of the apparatus because it is replaced for a certain period of time and is subject to maintenance or the like. It has a structure that can be removed independently.

On the other hand, the image exposure means is always kept stationary, the period of use is remarkably longer than that of the image forming body, and there are also structural reasons that it is installed inside the image forming body. In many cases, it is directly fixed to the main body of the device.

Therefore, the image forming body repeats the work of setting the position of the charging device and the optical system of the image exposing means each time the device is attached to or detached from the main body of the device, and the position of the image forming member is mechanically regulated with high accuracy. Nevertheless, the exposure optical system causes a change in the imaging distance that cannot be optically ignored, and a change in the distance between the image forming body and the corona discharge wire between the charging device and the grid causes a change in the image. Sharpness may be reduced. In addition, due to the fluctuation of the distance between the exposure optical system and the charging device or the imbalance of the pressing force of the blade of the developing device or the cleaning device with respect to the cylindrical image forming body that rotates during the driving of the image forming device. However, there is a drawback that a stable rotation of the photosensitive drum cannot be obtained and a high quality image cannot be obtained.

The present invention solves this problem and improves the result.
Taking into consideration the use of a photoreceptor having a relatively long life in recent years, it has been realized that the image forming unit is integrated with the image exposing unit, and the gap between the image forming unit and the exposure optical system is further reduced. Guarantee, and guarantee of the gap between the image forming body and the charging device,
In particular, it is an object of the present invention to provide a color image forming apparatus capable of recording a high quality image, in which each gap can be guaranteed even during driving, and a well-balanced rotation of the photosensitive drum can be obtained. is there.

[0009]

The above object is to provide a color image in which a plurality of sets of charging means, image exposing means, and developing means are arranged around an image forming body for forming an electrostatic latent image. In the image forming apparatus, the image exposing unit is provided on the first supporting member provided inside the image forming body, and the charging unit or the cleaning unit is provided on the second supporting member provided outside the image forming unit. The present invention is achieved by a color image forming apparatus characterized in that at least one of them is provided (first invention). The first support member and the second support member are arranged integrally with each other, the color image forming apparatus, the first support member and the second support member Is a color image forming apparatus characterized by being arranged concentrically, the second supporting member,
A color image forming apparatus, characterized in that a guide means for attaching and detaching the developing means is provided, and the second supporting member has a transfer paper of a transfer paper to a transfer means for transferring a toner image. A color image forming apparatus or the like which is provided with a guide member is a preferred embodiment of the first invention.

Further, the above object is to arrange a plurality of sets of charging means, an image exposing means and a developing means included in the image forming body around an image forming body for forming an electrostatic latent image,
A color image forming apparatus which forms an image by superposing a toner image on the image forming body by repeating charging of the image forming body by the charging means, image exposure by the image exposing means and development by the developing means. In the above, the image exposing means is disposed on a supporting member, the drive shaft of the image forming body is provided through the center of the supporting member, the driving member is provided at one end of the driving shaft, and the image forming body is driven at the other end. This is achieved by a color image forming apparatus characterized in that a connecting portion for connecting the shaft is provided (second invention). A color image forming apparatus, wherein the image forming body is detachably attached to the color image forming apparatus, is a preferred embodiment of the second invention.

Further, the above object is to arrange a plurality of sets of charging means, an image exposing means and a developing means contained in the image forming body around the image forming body for forming an electrostatic latent image,
A color image forming apparatus which forms an image by superposing a toner image on the image forming body by repeating charging of the image forming body by the charging means, image exposure by the image exposing means and development by the developing means. In the periphery of the image forming body, four sets of the charging means, the image exposing means, and the developing means are arranged, and the developing means are arranged horizontally with respect to the image forming body. In addition, the present invention is achieved by a color image forming apparatus characterized by being arranged so as to press the image forming body at vertically symmetrical and horizontally symmetrical positions (third invention). The angle formed by the developing means arranged symmetrically in the vertical direction is 45 ° or more and 90 ° or more.
A color image forming apparatus having the following features is a preferred embodiment of the third invention.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming process and each mechanism of an embodiment of a color image forming apparatus constituting the present invention will be described with reference to FIG. FIG. 1 is a sectional configuration diagram showing an example of a color image forming apparatus suitable for carrying out the present invention.

Reference numeral 10 denotes a photosensitive drum which is a cylindrical image forming body, and a transparent conductive layer is formed on the outer periphery of a cylindrical base body formed of a transparent member such as optical glass or transparent acrylic resin.
An a-Si layer or a photosensitive layer such as an organic photosensitive layer (OPC) is formed. 11Y, 11M, 11C and 11K are scorotron chargers, which are charging devices, used in the image forming process of each color of yellow (Y), magenta (M), cyan (C) and black (K). 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.

12Y, 12M, 12C and 12K are FL (phosphor emission), EL (electroluminescence) and PL (plasma discharge) in which light emitting elements arranged in the axial direction of the photoconductor drum 10 are arranged in a line in an array. , LI, which is an array of LEDs (light emitting diodes) and elements with optical shutter function
SA (photomagnetic effect optical shutter array), PLZT (transmissive piezoelectric element shutter array), LCS (liquid crystal shutter)
In an exposure optical system that is an image exposure device that is configured as a unit with an exposure element such as an image pickup element and a SELFOC lens as a unity-magnification imaging element, an image signal of each color read by a separate image reading device is read from a memory. The signals are sequentially taken out and input as electric signals to the exposure optical systems 12Y, 12M, 12C and 12K, respectively. The exposure optical system 12Y, 12
Each of M, 12C and 12K is attached to a cylindrical first supporting member 20 and is housed inside the base of the photosensitive drum 10.

13Y, 13M, 13C and 13K are yellow (Y), magenta (M), cyan (C) and black (K).
A developing device which is a developing device using a non-contact developing method for accommodating a one-component developer or a two-component developer, and rotates in the same direction while maintaining a predetermined gap with respect to the peripheral surface of the photosensitive drum 10. It has sleeves 131Y, 131M, 131C and 131K.

The developing devices 13Y, 13M, 13C and 13K
Are the scorotron chargers 11Y, 11M, 11C and 11 described above.
The electrostatic latent image formed on the photosensitive drum 10 by the charging by K and the image exposure by the exposure optical systems 12Y, 12M, 12C and 12K is reversely developed in a non-contact state by applying a developing bias voltage.

In the image reading apparatus which is a separate body from this apparatus, the original image is once read as an image signal read by an image pickup device or an image edited by a computer as an image signal for each color of Y, M, C and K. Stored and stored in memory.

By the start of image recording, the photoconductor driving motor is started to rotate the photoconductor drum 10 clockwise.
At the same time, application of electric potential to the photoconductor drum 10 is started by the charging action of the scorotron charger 11Y.

After the photosensitive drum 10 is applied with an electric potential,
In the exposure optical system 12Y, 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) image of the original image is formed on the photosensitive layer on the surface by the rotational scanning of the drum. To form an electrostatic latent image corresponding to.

The latent image is reversely developed by the developing device 13Y in a state where the developer on the developing sleeve is not in contact with the latent image, and a yellow (Y) toner image is formed according to the rotation of the photosensitive drum 10.

Next, the photosensitive drum 10 is further given a potential on the yellow (Y) toner image by the charging action of the scorotron charger 11M, and the second image of the exposure optical system 12M.
Exposure is performed by an electric signal corresponding to the color signal of, i.e., the magenta (M) image signal, and non-contact reversal development by the developing device 13M causes the magenta (M) toner on the yellow (Y) toner image. The images are sequentially superimposed and formed.

Scorotron charger by similar process
11C, exposure optical system 12C and developing device 13C
(C) toner image corresponding to the color signal of, the scorotron charger 11K, the exposure optical system 12K, and the developer 13K.
Thus, a black (K) toner image corresponding to the fourth color signal is sequentially superposed and formed, and a color toner image is formed on the peripheral surface of the photosensitive drum 10 within one rotation.

These exposure optical systems 12Y, 12M, 12C and
The exposure of the organic photosensitive layer of the photoconductor drum 10 by 12K is performed 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 the image corresponding to the first color signal. It is possible to form an electrostatic latent image.

In this way, the color toner image formed on the peripheral surface of the photosensitive drum 10 is sent out from the paper feed cassette 15 in the transfer device 14a, conveyed to the timing roller 16, and driven by the timing roller 16. It is transferred onto a transfer paper P which is a transfer material that is fed in synchronization with the toner image on the photosensitive drum 10.

The transfer paper P on which the toner image has been transferred is removed from the charge by the static eliminator 14b and separated from the peripheral surface of the drum, and then is transferred to the fixing device 17 by the transfer belt 14e. The fixing device 17 is heated and pressure-bonded to fuse and fix the toner on the transfer paper P, and then the toner is ejected from the fixing device 17.
The sheet is conveyed by the pair of sheet discharging rollers 18a and is discharged onto the sheet discharging tray 200 at the upper part of the apparatus via the sheet discharging roller 18.

On the other hand, the photosensitive drum 10 from which the transfer paper has been separated has the cleaning blade 19a in the cleaning device 19.
The surface of the photoconductor drum 10 is rubbed to remove and clean residual toner, and the toner image of the original image is continuously formed or is temporarily stopped to form a new toner image of the original image. The waste toner scraped off by the cleaning blade 19a is discharged to a waste toner container (not shown) by the toner transport screw 19b.

The photoreceptor drum 10 has a plurality of scorotron chargers on the outer peripheral surface thereof even if the diameter of the drum is relatively small because the exposure optical system is housed therein.
11Y, 11M, 11C and 11K, developing units 13Y, 13M, 13C and 13K, etc. can be arranged, and the volume of the apparatus can be made compact by using a small diameter drum having an outer diameter of 60 mm to 150 mm. Can be done.

An embodiment of the configuration of the first invention of the present invention will be described with reference to FIGS. 2 is a cross-sectional view of a main part of FIG. 1, and FIG. 3 is a side cross-sectional view taken along the line AA-A of FIG.

Support member 20 which is a cylindrical first support member
Is provided with exposure optical systems 12Y, 12M, 12C and 12K, and three guide rollers 22r.
The exposure optical system 20 is fixed to the side plate 41 at the rear part of the apparatus main body with screws 61 while the exposure optical systems 12Y, 12M, 12C and 12K and the three guide rollers 22r are attached. Photoreceptor drum 10 in which front flange 10a and rear flange 10b are integrated at both ends
Is fitted into a support shaft 20j provided on the first support member 20 from the front surface (left side in FIG. 3) of the apparatus main body, and is rotatable by a bearing 20k provided on the front flange 10a and three guide rollers 22r. Supported. At this time, the rear flange
Photoconductor drum gear 20g provided on 10b and main body drive gear
40g is coupled, and the photosensitive drum 10 is brought into a state of being rotated through the main body drive gear 40g by driving a photosensitive drum drive motor (not shown) provided in the main body of the apparatus.

The scorotron chargers 11Y, 11M, 11C and 11K, and the cleaning device 19 are mounted inside the cylindrical portion of the second support member 50. The reference pin 147 provided on the rear side plate 41 and the second support member 5 so that the first support member 20 and the second support member 50 are aligned with each other.
The second support member 50, to which the scorotron chargers 11Y, 11M, 11C, and 11K are attached in a state in which the reference hole 156 provided in 0 is fitted, is the center of the support shaft of the photosensitive drum 10, that is, the photosensitive drum. The center of the body drum 10, the center of the first support member 20, and the center of the cylindrical portion of the second support member 50 are fitted in the end portion of the first support member 20 in a state of being overlapped with each other. The support member 60 provided with the bearing 60b is the bearing 60.
b is fitted to the support shaft 20j, and the fitting portion 60a is fitted to the second support member 50, and the photosensitive drum 10 is fixed to the side plate 40 on the front side of the apparatus main body with the screw 62 in a supported state.

During maintenance and inspection of the device body, screws 62
With the support member 60 removed from the support shaft 20j, the scorotron chargers 11Y, 11M, 11C and 11K, the cleaning device 19, the photosensitive drum 10, etc. can be attached / detached and replaced.

An embodiment of the configuration of the second invention of the present invention will be described with reference to FIG. FIG. 4 is a side sectional view showing a main part of the second invention. The members having the same functions as those in the above embodiment are designated by the same reference numerals.

Support member 20 which is a cylindrical first support member
The exposure optical systems 12Y, 12M, 12C and 12K, the guide rollers 22r at three points, and the bearings 120a, 120 at both ends of the through hole 125 provided at the center of the cylindrical portion of the first supporting member 20.
b is provided, and the first supporting member 20 is the exposure optical systems 12Y, 12M, 12C and 12K, and the guide rollers 22 of three points.
With the r etc. attached, screw 63
Fixed by. The photosensitive drum 10 in which the front flange 10a and the rear flange 10b are integrated on both ends is fixed to the drive shaft 30 of the photosensitive drum provided at the center of the photosensitive drum 10 by fixing the front flange 10a with the fixing pin 10c. Are joined together (joint part). The drive shaft 30, which is integrally coupled by the coupling portion by the photosensitive drum 10 and the fixing pin 10c, is inserted into the bearings 120a and 120b through the through hole 125 provided at the center so as to overlap with the cylindrical portion of the first supporting member 20. It is arranged in a supported state. A retaining ring 32 and a drive gear 33g are attached to the rear portion of the apparatus main body on the side opposite to the coupling portion provided on the drive shaft 30. The drive gear 33g is driven by the fixed pin 34.
Fixed at 30.

Inside the cylindrical portion of the second support member 50, the scorotron chargers 11Y, 11M, 11C and 11K, and the cleaning device 19 are attached. The second support member 5 and the reference pin 247 provided on the rear side plate 41 so that the first support member 20 and the second support member 50 are aligned with each other.
The second support member 50, to which the scorotron chargers 11Y, 11M, 11C, and 11K are attached in a state in which the reference hole 256 provided in 0 is fitted, is the center of the drive shaft 30 of the photosensitive drum 10.
That is, the center of the photosensitive drum 10, the center of the first supporting member 20, and the center of the cylindrical portion of the second supporting member 50 are fitted in the end portion of the first supporting member 20 in a state of being overlapped with each other. .
The support member 160 to which the bearing case 53a including the bearing 53 is attached is the drive shaft 30 of the photosensitive drum 10.
In addition, the fitting portion 160a is fitted to the second support member 50, and is fixed to the side plate 40 on the front side of the apparatus main body by the screw 65 while the photosensitive drum 10 is axially supported. Further, the retaining ring 31 at the front part is fitted into the drive shaft 30. The drive motor M and the motor gear 44g are attached to the motor mounting plate 42 so that the motor gear 44g is connected to the drive gear 33g.
The motor mounting plate 42 is mounted on the side plate 41 from the rear portion of the device body. The drive shaft 30 is rotated by the drive of the drive gear 33g, and the photoconductor drum 10 passes through the connecting portion to become the photoconductor drum.
The rear flange 10b is rotatably supported and rotated by three guide rollers 22r provided on the first supporting member 20.

At the time of maintenance and inspection of the apparatus main body, with the retaining ring 31 and the screw 65 removed and the support member 160 removed from the drive shaft 30, the scorotron charger 11Y,
11M, 11C and 11K, the cleaning device 19 can be attached / detached / replaced, and further, the fixing pin 10c of the coupling portion can be pulled out to attach / detach / replace the photosensitive drum 10.

Another embodiment of the first and second aspects of the present invention will be described with reference to FIGS. 5 and 6. Figure 5
It is a figure which shows the principal part cross section, and FIG. 6 is a sectional side view in BOB of FIG. The members having the same functions as those in the above embodiment are designated by the same reference numerals.

Front flange 10a and rear flange 10b at both ends
The photosensitive drum 10 in which is integrated with the drive shaft 30 of the photosensitive drum provided at the center of the photosensitive drum 10 has a front flange.
10a is fixedly fixed by a fixing pin 10c (coupling portion). 20 is an exposure optical system 12Y, 12M, 12C and 12K
Is a columnar first support member in which a bearing 20a is press-fitted in the front part and a bearing 23a is included in the rear part.
The connecting member 21 of the supporting member to which the point guide roller 22r is attached is fixed by the screw 24. The drive shaft 30 integrated with the photoconductor drum 10 passes through a through hole 25 provided at the center of a column through a first support member 20 into which the exposure optical systems 12Y, 12M, 12C and 12K are integrated. The rear flange 10b of the photoconductor drum 10 is fitted while being supported by the three guide rollers 22r provided on the coupling member 21. Further, the drive shaft 30 has a retaining ring at the rear of the bearing case 23.
After mounting 32, a drive gear 33g, which is a drive member for driving the photoconductor drum 10, is fixed to the end of the rear part of the opposite side of the coupling part of the photoconductor drum 10 and the drive shaft 30 with the fixing pin 34. Fix it.

On the other hand, reference numeral 150 denotes a second supporting member having a U-shaped cross section. The second supporting member 150 has a U-shaped bottom portion and is aligned with a hole 55 provided at the center of the cylindrical portion. bearing
The bearing case 53 including 53a is attached, and further, the scorotron chargers 11Y, 11M, 11C and 11K, and the cleaning device 19 are attached inside the cylindrical portion of the second support member 150. Scorotron charger 11Y, 11
The bearing 53a portion of the second support member 150 to which M, 11C, 11K and the like are attached is fitted to the end portion of the drive shaft 30 on the coupling portion side, and the center of the drive shaft of the photosensitive drum 10, that is, the photosensitive drum 10 With the center, the center of the first supporting member 20, and the center of the cylindrical portion of the second supporting member 150 superposed, the end of the cylindrical portion of the second supporting member 150 is joined by the screw 54. 21 is attached, the first support member 20 and the second support member 150 are integrally coupled via the coupling member 21,
A process unit 300 is formed. Reference numeral 31 is a retaining ring at the end of the joint.

As shown in FIG. 6, the process unit 300 is configured to be attachable / detachable to / from the main body of the color image forming apparatus. When the process unit 300 is attached / detached, a member close to the photosensitive drum 10, for example, a developing unit. Vessels 13Y, 13M,
The 13C and 13K, the transfer device 14a, the static eliminator 14b, and the like are retracted from the photosensitive surface of the photosensitive drum 10 in advance and the second support member 150 is provided.
It is performed in a state of being further separated. Process unit 300
Is a guide member R1 that is formed by extending two left and right guide rails G1 and G2 fixed to the second support member 150 outside the process unit 300 to the front and rear side plates 40 and 41 of the apparatus main body. , R2, inserted in the direction of the arrow in FIG. 6 (rightward in the figure), and provided on the second support member 150 and the reference pins 46 and 47 provided on the front and rear side plates 40 and 41 of the apparatus body. The reference holes 51 and 52 are connected to each other, and a locking member (not shown) is connected to a predetermined position between the side plates 40 and 41 of the apparatus main body,
The exposure optical systems 12Y, 12M, 12C and 12 are provided on the first support member 20.
K is a charging device for the second supporting member 150, which is a scorotron charger 11Y, 11M, 11C and 11K, and a cleaning device.
It is installed with 19 etc. attached.

When the process unit 300 is mounted, the drive gear 33g fixed to the drive shaft 30 is connected to the motor gear 44g of the photosensitive drum drive motor M fixed via the mounting plate 42 of the rear side plate 41. The first and second support members 20 and 150 fixedly coupled to the apparatus body by locking members and reference pins 46 and 47 not shown in the apparatus body,
Drive gear driven by the photosensitive drum drive motor M
33g rotates, the drive shaft 30 which is supported by the front and rear bearings 53a, 23a and passes through the through hole 25 at the center of the first support member 20 is rotated, and the drive shaft 30 has a front flange at the coupling portion. The photosensitive drum 10 coupled via the 10a is rotatably supported and rotatably supported by the three guide rollers 22r provided on the coupling member 21 at the rear flange 10b of the other end.

FIG. 7 shows another embodiment of the supporting member, and shows an example of the supporting member in which the first supporting member and the second supporting member are integrated. The members having the same functions as those in the above embodiment are designated by the same reference numerals.

An integrated support member 120 having a U-shaped cross section
In the inner cylindrical part, the exposure optical systems 12Y, 12M, 12C and
12K on the outer cylindrical part, scorotron charger 11Y, 11
M, 11C and 11K, a cleaning device 19, and three guide rollers 22r are attached to the connecting portion. As in the above-described embodiment, the drive shaft 30 integrally connected to the photosensitive drum 10 by the fixing pin 10c at the connecting portion is the support member 120.
Through the central through hole 125 provided at the center where the outer cylindrical portion and the inner cylindrical portion overlap with each other, the bearings 120a, 120
The photosensitive drum 10 is driven by a drive gear 33g provided on the opposite side of the coupling portion.
However, at the rear flange 10b of the photosensitive drum 10, the support member 120
It is rotatably supported and rotated by three guide rollers 22r provided in the. Reference numeral 260 denotes a support member of the support member 120, which is fixed to the support member 120 with a screw 66 to form a process unit 400 which is detachable from the apparatus main body.

FIG. 8 shows another modification of the second support member described in FIGS. 5 and 6, and the second support member having the scorotron chargers 11Y, 11M, 11C and 11K attached thereto. 250, developing units 12Y, 12M, 12C and 12K
Upper guide plates 252Y, 2 which are guide means for attaching and detaching
52M, 252C and 252K, and lower guide plates 251Y, 251M, 25
1C and 251K are integrally provided, and a transfer paper guide member 25
3 is also integrated. Further, the upper guide plate and the lower guide plate can be provided integrally, and the above-mentioned guide means and transfer paper guide portion can be provided on the integrated support member 120 shown in FIG. It is possible.

Regarding the third invention of the present invention, FIG. 9 and FIG.
Will be explained. 9 is a diagram showing a preferred arrangement of the developing device, and FIG. 10 is a partially enlarged view of FIG.

A horizontal line Q1 is passed through the center of the photosensitive drum 10.
The developing sleeves 131Y, 131M, 131C and 1 are bisected by -O-Q2 and are formed diagonally at an angle α.
Abutting rollers 135Y, 1 provided with 31K on each developing device
35M, 135C and 135K with even pressing force to photoconductor drum 10
The four developing devices 13 are symmetrical vertically with respect to the photoconductor drum 10 and symmetrically horizontally with respect to the photoconductor drum 10 so that they are pressed against each other.
Y, 13M, 13C and 13K are arranged. Developer 13Y, 13
M, 13C and 13K are fulcrums 162Y, 162M, 162C and 162
Developing device pressing levers 161Y, 161M, which are rotated around K,
Pressing springs 163Y, 163M, 16 provided on 161C and 161K
Pressing plates 164Y, 164M, 164C and 1 by 3C and 163K
Pressing the rear part of the developing device with 64K, hitting rollers 135Y, 135
The photoconductor drum 10 is pressed against M, 135C and 135K.

As shown in FIG. 9, the transfer device 14a is formed at angles β and γ to the right and left with respect to the line O-Q3 which is orthogonal to the horizontal line so that the force balance with the photosensitive drum 10 is maintained. And the cleaning device 19 is arranged. The angle α formed by the upper and lower developing units is preferably 45 ° ≦ α ≦ 90 °, and when 45 ° or less,
If the rotation of the image forming body is likely to be unstable and the angle is 90 ° or more,
The pressure of the developing device is not stable. In order for the transfer area of the transfer device to be appropriate, β is preferably 10 ° ≦ β ≦ 40 °, and correspondingly, the contact position γ of the cleaning blade 19a is also 10 °.
≦ γ ≦ 40 ° is preferable.

As shown in FIG. 10, in order to use the upper and lower developing devices in common, the relationship of the magnetic pole angle with respect to the image forming member is the same between the developing sleeves, and α = 45 ° is set to N near the developing region. , The magnetic pole angle δ of S is 45 °, 22.5 °,
When α = 60 °, the angle δ between the N and S magnetic poles near the development area is
It is preferable that the fixed magnetic poles are arranged such that the angle δ between the N and S magnetic poles near the developing area is 60 °, 30 °, α = 90 °, and 90 °, 45 °, 22.5 °.

[0048]

According to the first to third aspects of the present invention, even if the image forming body is exchanged at a predetermined time or undergoes maintenance or the like, the position of the image forming body is mechanically highly regulated at the initial stage of assembly and the exposure optical system. The gap between the system and the gap between the image forming body and the corona discharge wire or grid of the charging device can be kept constant without any fluctuation in the positional accuracy, and a good image can be kept. Further, according to claim 4, the developing device is properly guided to the image forming body, and the accurate position setting between the developing device and the image forming body is performed. Further, according to the fifth aspect, the advancing angle of the transfer paper to the photosensitive drum is kept constant, and good transfer is always possible.

According to the sixth or seventh aspect of the present invention, while the image forming apparatus is being driven, the gap between the image forming body and the exposure optical system, and the image forming body and the charging device are provided with respect to the rotating cylindrical image forming body. The gap is maintained constant, and a well-balanced driving rotation of the photosensitive drum is obtained, which enables high-quality image recording.

According to the eighth or ninth aspect of the invention, the photosensitive drum is rotated by a well-balanced pressing force of the blade of the developing device or the cleaning device against the cylindrical image forming body which rotates during the driving of the image forming apparatus. Stable rotation was obtained, and a high quality image was obtained. Furthermore, it has become possible to provide a color image forming apparatus that enables common use of a developing device.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing an example of a color image forming apparatus suitable for carrying out the present invention.

FIG. 2 is a cross-sectional view of a main part of FIG.

FIG. 3 is a side sectional view taken along line AOA of FIG.

FIG. 4 is a side sectional view showing an essential part of the second invention.

FIG. 5 is a cross-sectional view of an essential part showing another embodiment of the configurations of the first and second inventions.

6 is a side sectional view taken along the line B-O-B in FIG.

FIG. 7 is a view showing another embodiment of the support member.

FIG. 8 is a diagram showing another modification of the second support member.

FIG. 9 is a view showing a preferable arrangement of developing devices.

FIG. 10 is a partially enlarged view of FIG.

[Explanation of symbols]

 10 Photoconductor drum 10a Front flange 10b Rear flange 10c Fixing pin 11Y, 11M, 11C, 11K Scorotron charger 12Y, 12M, 12C, 12K Exposure optical system 13Y, 13M, 13C, 13K Developer 15 Paper feed cassette 16 Timing roller 17 Fixing device 19 Cleaning device 20 First support member 22r Guide roller 25, 125 Through hole 30 Drive shaft 33g Drive gear 50, 150, 250 Second support member 120 Support member 164Y, 164M, 164C, 164K Press plate 251Y, 251M , 251C, 251K Lower guide plate 252Y, 252M, 252C, 252K Upper guide plate 253 Transfer paper guide member 300, 400 Process unit G1, G2 Guide rail R1, R2 Guide member

Claims (9)

[Claims] 1. A color image forming apparatus in which a plurality of sets of charging means, image exposing means, and developing means are arranged around an image forming body for forming an electrostatic latent image. The image exposing means is provided on a first supporting member provided inside the image forming apparatus, and at least one of the charging means and the cleaning means is provided on a second supporting member provided outside the image forming body. A color image forming apparatus characterized by the above. 2. The color image forming apparatus according to claim 1, wherein the first support member and the second support member are integrally provided. 3. The color image forming apparatus according to claim 1, wherein the first support member and the second support member are concentrically arranged. 4. The color image formation according to claim 1, wherein the second supporting member is provided with guide means for attaching and detaching the developing means. apparatus. 5. The transfer paper guide member for transferring the transfer paper to a transfer device for transferring a toner image, the second support member being provided with a transfer paper guide member. 1
The color image forming apparatus according to item. 6. A plurality of sets of charging means, an image exposing means and a developing means included in the image forming body are arranged around the image forming body for forming an electrostatic latent image, and the image forming body is provided. On the other hand, in a color image forming apparatus for forming an image by superposing a toner image on the image forming body by repeating charging by the charging unit, image exposure by the image exposing unit and development by the developing unit, a supporting member The image exposure means, the drive shaft of the image forming body is provided through the center of the supporting member, the drive member is provided at one end of the drive shaft, and the image forming body and the drive shaft are connected at the other end. A color image forming apparatus characterized in that a connecting portion is provided. 7. The color image forming apparatus according to claim 6, wherein the image forming body is detachably attached to the color image forming apparatus. 8. A plurality of sets of charging means, an image exposing means and a developing means included in the image forming body are arranged around the image forming body for forming an electrostatic latent image, and the image forming body is provided. On the other hand, in the color image forming apparatus, the toner image is superimposed on the image forming body by repeating the charging by the charging unit, the image exposure by the image exposing unit, and the development by the developing unit to form an image. Four sets of the charging means, the image exposing means, and the developing means are arranged around the formed body, and the developing means is provided with respect to the image formed body.
A color image forming apparatus, wherein the color image forming apparatus is arranged horizontally and is arranged so as to press the image forming body at vertically symmetrical and horizontally symmetrical positions. 9. The color image forming apparatus according to claim 8, wherein an angle formed by the vertically symmetrical developing means is 45 ° or more and 90 ° or less.