JPH03259271A - Color image forming device - Google Patents

Abstract

PURPOSE:To make this device compact and to prevent a writing means from being stained by integrally forming a belt-like photosensitive body, a cleaning device, an electrifier, etc., as a belt unit. CONSTITUTION:The writing means 10 making an image exposure incident between a driving roller 2 and a follower roller 3, where a belt like photosensitive body inside a belt like photosensitive body 4 is stretched is disposed, and the belt unit incorporating the stretched belt like photosensitive body 1, an internal writing means 10, the cleaning device 7,and the electrifier 8 is attached/detached to/from a device main body. The belt like photosensitive body 4 is used so that the image exposure is made incident on the reverse back surface of the front surface on which toner image is formed and an electrostatic image can be formed, and the image exposure is made incident by the writing means 10 disposed on the inner part of its stretch. Thus, the image exposure is made incident on the back surface where the toner image is not formed, and constant conditions are obtained. The staining of the light emitting surface of the writing means is reduced, and the device is made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus such as a color electrophotographic copying machine, and in particular, to a color image forming apparatus such as a color electrophotographic copying machine. The present invention relates to a color image forming apparatus that forms a color image by repeating steps 1 and 2 and developing an electrostatic image into a toner image, and transfers and fixes the color image onto a transfer material.

[Conventional technology]

As the above-mentioned color image forming apparatus, one in which an electrostatic image is formed by applying imagewise exposure light onto the surface of a photoreceptor is known. To do this, ■ In the first electrostatic image formation of color image formation, image exposure is applied to the cleaned surface of the photoconductor, and in the second and subsequent electrostatic image formation, the toner image-bearing surface of the photoconductor is exposed. As mentioned above, the image exposure input conditions change; ■ Since the image exposure light is incident on the surface of the photoconductor that has the toner image, the lens surface or glass surface of the writing means that emits the image exposure light may become dirty. There are problems such as: (1) the provision of writing means on the outside of the photoreceptor increases the size of the apparatus;

In addition, with a drum-shaped photoreceptor, it is not possible to install multiple developing devices without increasing the diameter of the photoreceptor, resulting in an even larger device. There is also.

On the other hand, in a monochrome image forming apparatus, a drum-shaped or belt-shaped photoreceptor having a photoconductive layer provided on a transparent conductive base is used. A copying exposure means is provided on the layer side to scan and expose the original and the reflected light from the original is incident thereon, and a printer exposure means is provided on the back side, that is, the base side, for applying image exposure based on a signal based on image data. Unexamined Japanese Patent Publication 1986-14
It is known from the publication No. 8480. In such a monochromatic image forming apparatus, the effect of providing a writing means for making image exposure incident on the back side of the photoreceptor is almost limited to miniaturization of the image forming apparatus.

In the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 61-148480, it takes time to maintain the photoreceptor, the charger around it, the cleaning device, the developing device, etc., and the relative positions of these components tend to change due to maintenance. There is a problem that has to be dealt with by experts.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned circumstances, and it is possible to reduce the change in the image exposure incident conditions each time color image formation is performed and to reduce the dirt on the output surface of the writing means, making it possible to configure the apparatus compactly, and moreover, to The purpose of the present invention is to provide a color image forming apparatus in which a developing device can be easily installed, and maintenance of the photoreceptor, charger, cleaning device, multiple developing devices, etc. can be done easily and in a short time. do.

[Means to solve the problem]

The present invention forms a color image by repeatedly charging the cleaned surface of a rotating photoreceptor, forming an electrostatic image, and developing the electrostatic image into a toner image, and then transfers the color image to a transfer material. In a fixing color image forming apparatus, a photoconductor is a belt-shaped photoconductor whose back side receives image exposure to form the electrostatic image, and the belt-shaped photoconductor inside the belt-shaped photoconductor is stretched. A writing means for injecting the image exposure light is disposed between a driving roller and a driven roller, and a belt unit incorporating a stretched belt-shaped photoreceptor, an internal writing means, a cleaning device, and a charger is used in the apparatus. The color image forming apparatus is characterized in that it can be attached to and detached from the main body, and this configuration achieves the above object.

[Effect]

That is, in the color image forming apparatus of the present invention, a belt-shaped photoreceptor is used, which forms an electrostatic image by applying imagewise exposure to the back surface opposite to the front surface on which a toner image is formed, and the inside of the belt-shaped photoreceptor is Since the image exposure light is incident on the back surface on which the toner image is not formed, the conditions are constant and the exit surface of the writing means is less likely to get dirty, making the device compact. Moreover, a plurality of developing devices can be easily arranged side by side around the outer periphery of a belt-like photoreceptor, and the belt-like photoreceptor with writing means inside, a cleaning device, and a charger can be combined as a belt unit. Since they are attached to and detached from the main body of the apparatus as a whole, they can be easily maintained, and even an operator can easily replace the belt unit.
This provides the effect that the relative positions of the cleaning device, charger, etc. can be kept constant.

〔Example〕

The present invention will be explained below using illustrated examples.

1 and 2 are respectively schematic side views showing the configuration of an example of the color image forming apparatus of the present invention, FIG. 3 is a partial side view showing another example, and FIG. The belt unit frame j is set so that the distance between the developing sleeve and the photoconductor is constant. Y-Y arrow view and partially enlarged view of Figure 1 showing an example of installing
This figure and FIG. 8 are a z-2 arrow view and a partial side view of FIG. 1, showing an example of a coupling structure between a belt unit and a developing unit.

In the figure, l is a belt-shaped photoreceptor with a photoreceptor layer such as OPC provided on the surface of a transparent conductive support, and 2 and 3 are belt-shaped photoreceptors l stretched in contact with the back surface of the belt-shaped photoreceptor l in the direction of the arrow. A driving roller and a driven roller to be rotated, 4 is a belt-shaped photoreceptor 1
A belt guide member 5 that regulates the travel path between the driving roller 2 and the driven roller 3 is attached to the belt guide member 4 together with a slow-closing reflective shade 6, and the belt-shaped light passes through the light passing window 4a of the belt guide member 4. A static eliminating lamp 7 that illuminates the back surface of the photoreceptor l, a cleaning blade 7a that can be switched between an active position (solid line) and an inactive position (double-dashed line), and a toner collected by the cleaning blade 7a into a collected toner box (not shown). A cleaning device equipped with a transporting screw 7b, chargers 8, 81 to 84 uniformly charge the surface of the belt-shaped photoreceptor 1, and 9, 91 to 94 are attached to the belt guide member 4 to uniformly charge the surface of the belt-shaped photoreceptor 1. 10 is a light emitting element array writing means using an LED array that forms an electrostatic image in the form of dots on the front surface of a belt-like photoreceptor L by applying imagewise exposure to the back surface of the belt-shaped photoreceptor L, which is electrically charged; a modulated laser beam generating means (not shown) which is attached to the belt guide member 4 and causes image exposure light to enter the belt-shaped photoreceptor 1 through the light passing window 4b of the belt guide member 4 in the same manner as the light emitting element array writing means 9 to form an electrostatic image; Polygon mirror 10a, f-θ
It is a laser beam writing means using a lens 10b, a mirror 10c, etc., and is a light emitting element array writing means 9, 91--
94 and the laser beam writing means 1O are adjusted and fixed to the belt guide member 4 by adjusting screws 30, respectively, so that the relative positions with respect to the belt-shaped photoreceptor 1 are constant.

Reference numeral 11 uses a black conductive plan or felt that is provided before and after the image exposure output part of the belt guide member 4 to slow down the diffusion of image exposure and to wipe and ground the back surface of the belt-shaped photoreceptor 1. A light-shielding cleaning member, which includes the above-mentioned stretched belt-shaped photoreceptor l, cleaning device 7, and charger 8 or 8.
1 to 84 are integrated into the belt unit frame I2. In particular, it is preferable that the chargers 8, 81 to 84, etc., which maintain a constant distance from the belt-shaped photoreceptor 1, be incorporated into the belt unit frame 12 as shown in FIG.

In FIG. 4, the charger 8 has guide pins 8a implanted on both sides of its base frame slidably engaged with guides *12a provided on the belt unit frame 12.
When the bottom wall of the base frame is pushed by the spring 31 provided at 2, the upwardly protruding portions on both sides of the base frame come into contact with both side extension surfaces of the portion of the belt guide member 4 that guides the belt-shaped photoreceptor l; Thereby, the distance from the belt-shaped photoreceptor l is kept constant.

13Y, 13M, 13c, 13B are yellow (
Y) Toner, magenta (M) toner, cyan (C) toner, and black (B) toner are used as developers to develop the electrostatic image on the surface of the belt-shaped photoreceptor l by a non-contact reversal development method. ,B
These developing devices 13Y, 13M, 13c, and 13B are connected to the developing unit frame 14.
is integrally incorporated into. These developing devices 13Y, 1
3M.

130.13B also maintains a constant distance between the developing sleeve and the belt-shaped photoreceptor l, so it is preferable to incorporate it into the developing unit frame 14 as shown in FIGS. 5 and 6.

In FIGS. 5 and 6, the developing device t13c is placed in the developing unit 14 so that it can be pulled out upwardly,
By being pushed up by the spring 32 provided on the bottom surface of the developing unit frame 14, the spacer disk 33 loosely fitted on the rotating shaft of the developing sleeve guides the belt-shaped photoreceptor 1 of the belt guide member 4. The distance between the developing sleeve and the belt-shaped photoreceptor l is kept constant.

15 is a feed roller 17 from a cassette 16, a conveyance path 18,
a transfer device that transfers the toner image onto a transfer material fed into contact with the belt-shaped photoreceptor l via a register roller 19;
20 is a fixing roller that fixes the toner image on the transfer material; 21
is a paper discharge roller that discharges the transfer material on which the toner image has been fixed to a paper discharge section.

Formation of color images in the image forming apparatuses shown in FIGS. 1 and 2 is performed as follows. That is, in response to the start signal, the belt-shaped photoreceptor 1 is rotated by the drive roller 2 in the direction of the arrow, the static electricity of the belt-shaped photoreceptor 1 is removed by lighting the static elimination lamp 5, and the cleaning blade 7a of the cleaning device 7 is rotated as indicated by the two-dot chain line. The surface of the belt-shaped photoreceptor 1 is cleaned by switching from the non-operating position to the operating position shown by the solid line. A charger 8 uniformly charges the surface of the belt-shaped photoreceptor 1 that has been subjected to this static elimination and cleaning. The light emitting element array writing means 9 or the laser beam writing means 10 injects image exposure for one of the color image component colors, for example, a Y image, onto the back surface of the belt-like photoreceptor 1, which is charged. An electrostatic image in the form of dots is formed on the surface. This electrostatic image is transferred to the developing device 13Y.
is developed into a Y toner image. Other developing devices 13M, 13c, whose Y toner image forming surfaces are placed in an inactive state;
13B.

When it passes through the transfer device 15 and the static elimination lamp 5 and cleaning device 7 that have been switched to an inactive state and reaches the charger 8, it is uniformly charged again by the charger 8. As before, the light emitting element array writing means 9 or the laser beam writing means 10 injects image exposure for, for example, an M image onto the back surface of the belt-like photoreceptor l having the charged Y toner image, thereby exposing the belt-like photoreceptor l. An electrostatic image is formed on the surface of the body 1. This electrostatic image is transferred to the developing device 13M.
is developed into an M toner image. As a result, a two-color toner image consisting of a Y toner image and a M toner image is formed on the surface of the belt-shaped photoreceptor l. The two-color toner image forming surface is uniformly charged by the charger 8 in the same manner as before, and the back surface thereof is coated with a light emitting element array writing means 9 or a laser beam writing means l.
O is now incident for image exposure for the C image. The developing device 13C develops the electrostatic image formed on the surface of the belt-shaped photoreceptor 1 into a C toner image. As a result, a three-color toner image consisting of Y, M, and C toner images is formed on the surface of the belt-shaped photoreceptor 1. The three-color toner image,
Alternatively, the three-color toner image forming portion of the belt-like photoreceptor 1 is further uniformly charged by the charger 8, exposed to light for the B image by the light emitting element array writing means 9 or the laser beam writing means IO, and the developing device 13B A four-color toner image is transferred onto a transfer material by a transfer device 15 from the Y, M, C, B) toner image formed by the development.

The toner image is then fixed on the transfer material by a fixing roller 20.
The paper is discharged to a paper discharge section 22 by a paper discharge roller 21. On the other hand, the belt-shaped photoreceptor l to which the color toner image has been transferred is connected to a static elimination lamp 5.
When the cleaning device 7 is switched on, the surface is cleaned and prepared for the next color image formation.

Formation of a color image in an image forming apparatus equipped with the belt unit and developing unit shown in FIG. 3 instead of the belt unit and developing unit shown in FIG. 1 is performed as follows. That is, the belt-shaped photoreceptor l rotates in response to a start signal, the static eliminating lamp 5 removes static electricity from the belt-shaped photoreceptor l, the cleaning device 7 cleans it, the charger 81 uniformly charges it, and the light emitting element array writing means 91 injects image exposure for a Y image onto the back surface of the belt-shaped photoreceptor l, and the electrostatic image formed thereby is developed into a Y toner image by the developing device 13Y. Similarly, the charger 82 uniformly charges the Y toner image forming surface.
The light emitting element array writing means 92 injects image exposure for the M image onto the back surface, and the developing device 13M develops the electrostatic image formed on the surface into an M toner image, resulting in Y and M two-color toners. A charger 83 uniformly charges the image forming surface, and a light emitting element array writing means 93 writes C on the back surface.
The developing device 13c develops the electrostatic image formed on the surface of the image into a C toner image, and the thus formed three-color toner image of Y, M, and C is transferred onto a transfer material. A charger 84 uniformly charges the transferred or three-color toner image forming surface, and a light emitting element array 94 injects image exposure for the B image onto the back surface thereof.
The electrostatic image thus formed on the surface is transferred to a developing device 13B.
The four color toner images of Y, M, C, and B are developed into a B toner image and transferred to a transfer material, and the rest is then transferred to the transfer material in the same manner as in the image forming apparatus shown in FIG. The toner image is fixed and discharged, and the belt-shaped photoreceptor 1 is neutralized and cleaned.

In the image forming apparatus described above, if the transfer material jams between the cassette 16 and the paper ejection roller 21, one of the guide plates of the pair of conveyance paths 18, the register roller 19, the fixing roller 20, and the paper ejection roller 21, respectively. The first part of the main body frame 23 in which the outer guide plate, rollers, and transfer device 15 are arranged.
The left side portion 23a in the figures and FIG.
Since it can be opened as shown by the two-dot chain line in the figure, the jammed paper can be easily removed by opening it. In addition, as a countermeasure in the case where the transfer material is not sent to the fixing roller 20 side but adheres to the belt-shaped photoreceptor l, as for the examples shown in FIGS. 1 and 2, The upper part 23b of the main body frame 23, whose upper surface is the paper ejection part 22, is opened by a hinge around the left or right end with the left part 23a open as shown by the two-dot chain line in FIG. If it is movable, the transfer material can be easily removed. Measures to facilitate the removal of jammed paper, etc. are not limited to these.

Further, in the illustrated image forming apparatus, the belt unit and the developing unit are detachably connected, so that they can be integrally attached to and detached from the main body frame 23 as a process unit. This allows the belt unit, developing unit,
Maintenance such as replacing the battery can be done in a short time. When the upper part 23b is made open and rotatable as described above, the process unit can be attached and detached from the main body frame 23 from the open upper part, and is not limited to this.
It can also be done from the front or back of the page of the figure or Figure 2. An example of the coupling mechanism between the belt unit and the developing unit will be explained with reference to FIGS. 7 and 8.

In the coupling mechanism shown in FIG. 7.8, a suspension member 25 having a suspension pin 25a is slid into a total of four elongated holes 12b provided on both side walls of the belt unit frame 12 on the developing device 13Y side and 13B side. The belt unit frame 12 and the developing unit frame 14 are connected in a state in which the hanging members 25 are displaced so that the hanging members 25 on the developing device 13Y side and the developing device 13B side are spaced apart from each other. canceled,
In this state, the belt unit frame 12 is placed so that the suspension pin 25a of the suspension member 25 is in contact with the upper surface of the side wall of the developing unit frame 14, and the suspension member 25 is placed so that the suspension members 25 on the developing device 13Y side and 13B side approach each other. When the belt unit frame 12 is moved to the position shown in FIG. The developing unit frame 14 is lifted up integrally with the belt unit frame 12 in a state in which the developing unit frame 14 is positioned with respect to the belt unit frame 12 by contacting the same-diameter R portion of the seven vine portions 14a. The coupling mechanism is not limited to this. For example, the suspension pin 25a is fixed to the belt unit frame 12, and the seven hooks 14a on the developing device 13Y side and the 13B side of the developing unit frame 14 are oriented in the same direction. Even if the coupling is attached or detached by shifting the developing unit frame 14 in the left-right direction in FIG. 8, the suspension pin 2
It may be provided in the belt unit frame 12 so that the 5a can be inserted and removed between a position where it engages with a hole in the developing unit frame 14 and a position where it disengages from the hole. Any material may be used as long as it can be easily combined with the component frame 14 positioned and can be uncoupled.

Note that the image forming apparatus of the present invention is not limited to the one in which the belt unit and the developing unit are combined as described above.

〔Effect of the invention〕

In the color image forming apparatus of the present invention, since the writing means is not located on the developing device side, the apparatus can be configured compactly, and the writing means is not smeared with toner, so that the amount of light for image exposure does not decrease. Each image exposure in the color image forming process is incident on a surface where there is no toner image, so the conditions are constant, so good color images can be stably formed, and since a belt-shaped photoreceptor is used, Even if the device is configured compactly, it is easy to use multiple developing devices with large capacities, and furthermore, since the belt-shaped photoreceptor, cleaning device, charger, etc. are integrated into a belt unit, The excellent effect is that their maintenance can be easily performed and their relative positions can be kept constant.

[Brief explanation of drawings]

1 and 2 are respectively schematic side views showing the configuration of an example of the color image forming apparatus of the present invention, FIG. 3 is a partial side view showing another example, and FIG. The X-X arrow view of FIG. 1 shows an example in which the belt unit is installed in the frame so that the distance between the developing sleeve and the photoreceptor is constant, and FIGS. A Y-Y arrow view and a partially enlarged view of FIG. 1 showing an example of installing the belt unit, and FIGS. 7 and 8 are +-+ arrow views of FIG. FIG. 3 is a partial side view of FIG. l... Belt-shaped photoreceptor 2... Drive roller 3...
・Followed roller 4... Belt guide member 5,...
Static elimination lamp 7...Cleaning device 8.81
~84...Charger 9.91~94...Light emitting element array writing means lO.
...Laser beam writing means 12...Belt unit frame

Claims (4)

[Claims] (1) A color image is formed by repeatedly charging the cleaned surface of the rotating photoreceptor, forming an electrostatic image, and developing the electrostatic image into a toner image, and then transferring the color image to a transfer material and fixing it. In a color image forming apparatus, the photoreceptor is a belt-shaped photoreceptor whose back side receives image exposure to form the electrostatic image, and a driving mechanism in which the belt-shaped photoreceptor inside the belt-shaped photoreceptor is stretched. A writing means for injecting the image exposure light is disposed between the roller and the driven roller, and a belt unit incorporating a stretched belt-shaped photoreceptor, an internal writing means, a cleaning device, and a charger is connected to the main body of the apparatus. A color image forming apparatus characterized in that it can be attached to and detached from the image forming apparatus. (2) The belt-like photoreceptor rubs against the inside of the stretched belt-like photoreceptor to regulate the traveling path between the driving roller and the driven roller, and the position relative to the plurality of developing devices that perform the development. 2. A color image forming apparatus according to claim 1, further comprising a belt guide member that is determined. (3) The color image forming apparatus according to claim 2, wherein the writing means is fixed to the belt guide member so that its position can be adjusted. (4) The color image forming apparatus according to claim 1, wherein a plurality of developing devices are integrated as a developing unit and detachably connected to the belt unit.