JPH04195174A - Color image forming device - Google Patents

Abstract

PURPOSE:To improve operability at a repairing time and to make mutual positional accuracy between an image forming element member and a photosensitive body easy to be secured by setting color developing devices together in one block and setting a black developing device and the image forming element member together in one block. CONSTITUTION:A color image forming device is constituted of a color developing block 51 where the color developing devices 7 - 9 except a black color are mounted on the photosensitive body 5 and set to be attachable to and detachable from a main body frame 20, and a photosensitive body block 52 where an electrostatic charger 6, a transfer device 21, a destaticization device 22, a cleaning device 23 and the black color developing device 10 are set to be attachable to and detachable from the frame 20. Then, the color developing devices 7 - 9 are set together in one block 51 and the black color developing 10 whose using frequency and repairing frequency are many and the image forming element member are set together in one block 52. Besides, they are set to be attachable to and detachable from the frame 20. Thus, when repairing work is executed, the blocks 51 and 52 can be easily drawn out and the accuracy of a relative position between the image forming element member and the photosensitive body 5 is easily maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to color image forming apparatuses such as printers and copying machines that apply electrophotography.

Conventional technology To obtain multicolor images using electrophotography, the subject is separated into four colors (yellow, magenta, cyan, and black), and an image corresponding to each color is created on a photoreceptor. death,
This is done by transferring the created multicolor image onto paper.

FIG. 6 shows a conventional example of a color copying machine using electrophotography (for example, Japanese Patent Laid-Open No. 1-167772). The original placed on the original placing table 2 is scanned by the reading unit 1.
Color (yellow, magenta.

cyan, black), read it, and convert it into each electrical signal. Based on this electrical signal, a laser beam 4 corresponding to each color is generated by a laser light source section 3.

Since the surface of the photoreceptor 5 is uniformly charged by the charger 6, the laser beam 4 scans the photoreceptor 5, thereby forming an electrostatic latent image corresponding to each color on the photoreceptor 5. is made. Around the photoreceptor 5, in addition to the charger 6 described above, there is a yellow developing device 7. Mazetan developing device 8° Cyan developing device 9. A black developing device 10 is provided. When an electrostatic latent image corresponding to yellow is formed on the photoreceptor 5, a yellow developing device 7 is activated to develop the latent image on the photoreceptor with yellow toner. Similarly, when forming a magenta latent image, the magenta developing device 8 operates, when forming a cyan latent image, the cyan developing device 9 operates, and when forming a black latent image, the black developing device 10 operates, and the respective toners are used to develop the image. do.

When the four-color development is completed on the photoreceptor 5, the paper feed section 11
The paper 12 fed from the registration roller 13 and the roller 1
It reaches the transfer conveyance section 15 via 4. The multicolor image developed on the photoreceptor 5 is transferred to a paper 12 by a transfer conveyance section 15, and the paper 12 is sent to the next fixing section 16, and is ejected to the outside via a paper ejection roll 17. Ru. Further, since toner and charge remain on the photoreceptor 5 after the transfer, the residual toner is removed by the static elimination cleaning section 18 and the residual charge is also made uniform.

In the above color image creation, each color developing device 7 to 1
0, each developing device 7-10 is moved in the direction of arrow C, and the developing rollers 7a, 8a, 9a attached to the tip of each developing device 7-10 are moved.

10a is brought close to the photoreceptor 5. To make them inoperative, each of the developing devices 7 to 10 is moved in the direction of the arrow, and the developing rollers 7a to 10a are separated from the photoreceptor 5. This prevents inactive toner from adhering to the photoreceptor 5 and causing color mixing.

Particularly when the developing devices 7 to 10 are operated, accurately positioning the distance between each of the developing rollers 7a to 10a and the photoreceptor 5 to a predetermined value is necessary to align the development characteristics of each color and obtain an image with good color balance. This is extremely important. It is also important to facilitate handling when repairing each developing device 7 to 10 or replenishing toner. In order to maintain accuracy and facilitate repair as described above, in the conventional example, the developing devices 7, 8, 9, 10 were integrally stored in the storage means 19 as shown in FIG.

Problems to be Solved by the Invention In such a conventional electrophotographic color image forming apparatus,
Developing device? , 8.9.10 were integrally stored in the storage means 19, so there was a problem that it was heavy to pull out the storage means when repairing. Furthermore, among the four colors, the color developing device and the black developing device usually have different repair frequencies, but when trying to repair the black developing device, the storage means 19
When the color developing device is pulled out, the color developing device is also pulled out at the same time, which causes problems such as foreign matter getting mixed in and color toner and black toner mixing.

Furthermore, not only the mutual positional accuracy of the photoreceptor 5 and the developing devices 7 to 1o is important, but also the charger 9. The mutual positional accuracy between each of the static eliminating cleaning parts 18 and the like and the photoreceptor 5 is also important in order to obtain a good image. Below, the charger 6 and developing device placed around the photoreceptor 5? , 8.9, 10.
The static elimination cleaning section 1 and the like are referred to as image forming elements, but in the conventional example described above, the developing devices 7 to 1o are excluded (the image forming elements are separately incorporated in the main body frame 2o, so the photoreceptor 5 In order to ensure the mutual positional accuracy between the image forming element and the above-mentioned image forming element member, the mutual positional relationship may change due to repair work or the like.

The present invention solves the above-mentioned problems, and is easy to handle during repair (and also makes it easy to ensure mutual positional accuracy between the image forming elements arranged around the photoconductor and the photoconductor, so that high-quality images can always be obtained). The object of the present invention is to provide a color image forming apparatus that can obtain the following.

Means for Solving the Problems In order to achieve the above object, the present invention provides a photoreceptor that rotates on an axis fixed to a main body frame and can hold an electrostatic latent image;
A light source that separates a color image into a plurality of primary color lights and irradiates the photoreceptor, a plurality of developing devices corresponding to the plurality of color-separated primary colors and black, and a charger disposed around the photoreceptor. , a pre-transfer device, a static eliminator, and a cleaning device, and the plurality of color developing devices except for black are mounted so as to be detachable from the photoconductor at positions facing the photoconductor, and the photoconductor is mounted on the main body frame. a color developing block that is removable in the direction of the rotation axis; the charger, the pre-transfer device, the static eliminator;
The cleaning device and the black developing device are mounted on a photoconductor block that faces the photoconductor and is detachable from the main body frame in the direction of the rotation axis of the photoconductor.

Effect of the present invention With the above-described configuration, the color developing device is assembled into one block, and the black developing device and other image forming elements, which are frequently used and therefore repaired, are assembled into one block, and each block is connected to the main body. Since it is made detachable from the frame in the direction of the rotation axis of the photoreceptor, the block can be easily pulled out from the main body frame during repair work. It is also possible to avoid color mixing between the color toner of the color developing device and the black toner of the black developing device during repair work. Furthermore, there are frequently used black developing devices, chargers, pre-transfer devices, and static eliminators.

Since the image forming element member such as the cleaning device and the photoreceptor are combined into an integrated block, the accuracy of the relative position between the image forming element member and the photoreceptor can be easily maintained, and a stable image can be obtained.

Embodiment FIG. 1 is a side view of one embodiment of the present invention. Note that the same reference numerals are used for the same constituent members as those of the conventional example described above. A document placed on the document table 2 is scanned by the reading section 1 in four colors (yellow, magenta, cyan).

The laser beam 4 is converted into a laser beam 4 corresponding to each color, and the laser beam 4 scans the photoreceptor 5, whose surface is uniformly charged by the charger 6, and the photoreceptor is exposed to light. Electrostatic latent images corresponding to the respective colors are created on the body 5. Around the photoreceptor 5, a charger 6. Yellow developing device7. Magenta developing device8. A cyan developing device 9 and a black developing device 10 are provided, and the developing devices corresponding to the electrostatic latent images of each color operate to develop four colors on the photoreceptor 5. When the four-color development is completed on the photoconductor 5, the paper 12 supplied from the paper feed section 11 reaches the transfer conveyance section 15, and the multicolor image developed on the photoconductor 5 is transferred to the paper 12. The paper 12 is transferred to the next fixing section 16 and is ejected to the outside via a paper ejection roll 17. Further, since toner and electric charge remain on the photoreceptor 5 after the transfer, the residual potential is removed by the static eliminator 22, and the residual electric charge on the photoreceptor is also made uniform. Further, residual toner is removed by a cleaning device 23. The basics of the above series of color image creation operations are the same as in the conventional example.

One point in which the embodiment of the color image forming apparatus of the present invention differs from the conventional example is that, as shown in detail in FIG. (hereinafter referred to as color development block). Another point different from the conventional example is that, as shown in FIG. 3, the photoreceptor 5 and the image forming elements excluding the color developing device are integrated into a block (hereinafter referred to as a photoreceptor block). These developing blocks and photoreceptor blocks can be extracted from the main body frame 20 as shown in FIG. The details of the structure of each block will be explained below.

FIG. 2 shows the color developing block 51. In the figure, 7 is a yellow developing device, 8 is a magenta developing device 1. is a cyan developing device. The respective developing devices include developing rollers 7a, 8a, and 9a.

toner stirring plates 7d, 8d, 9d and cam contact plate 7c,
It has 8c and 9c. The developing device 7.8.9 is mounted on the storage means 19 so as to be slidable in the directions of arrows A and B, and is constantly biased in the direction of arrow B by a lever spring (not shown). In addition, storage means 1
9 is a storage means guide portion 19a that is guided by a guide rail 21 and can be attached or detached in the direction of the rotation axis of the photoreceptor 5. Storage means 1
9 is installed, the generatrix of each developing roller of the developing device and the generatrix of the photoreceptor 5 occupy a position opposite to each other in parallel. At this time, the cam contact plate 7c of each developing device.

Eccentric cams 7b, 8b, 9b are located immediately after 8c, 9c. The eccentric cams 7b, 8b, and 9b are fixedly provided inside the main body frame 20, and are selectively driven and rotated based on a control signal from a drive source (not shown) in the main body frame, so that the cams come into contact with each other. Select plates 7c, 8c, and 9c with arrow A
direction to selectively move the developing devices 7, 8, 9 to the developing position. FIG. 2 shows a state in which the developing device 8 has been selectively moved to the developing position. Further, FIG. 4 shows a state in which the color developing block 51 is removed from the main body frame 20, and from this state, each developing device 7.
．． 9 can be pulled out from the storage means 19 as needed to replenish toner. FIG. 4 shows a state in which the magenta developing device 8 is pulled out from the color developing block 51.

Next, FIG. 3 shows a photoreceptor block 52, in which 5 is a photoreceptor, 6 is a charger, 10 is a black developing device, and 2 is a photoreceptor block.
1 is a pre-transfer charger, 22 is a static eliminator, and 23 is a cleaning device. The charger 6 is fixed to the photoreceptor block frame 24 at a predetermined distance from the photoreceptor 5, and is used to uniformly charge the photosensitive layer on the surface of the photoreceptor to a predetermined electrostatic potential. . The black developing device 10 includes a developing roller 10a.
.

It has a cam contact plate 10c and a toner agitation device 10d, and is mounted so as to be rotatable in the directions of arrows A and B around the rotation fulcrum hole 24d of the photoreceptor block frame 24, and when not in operation, the developing The device 10 rotates in the direction of arrow B due to its own weight. Then, due to the rotation of the eccentric cam 10b, the developing roller 10a moves in the direction of the arrow, and the developing roller 10a approaches the photoreceptor 5 to perform black development. The pre-transfer charger 21 is used to adjust the electrostatic potential of the developed toner to a predetermined value before transferring the developed toner to paper, and is mounted on the photoreceptor block frame at a predetermined distance from the photoreceptor 5. It is fixed at 24. The static eliminator 22 is composed of a static eliminator 22a and a static eliminator lamp 22b, and makes the electrostatic potential on the photoreceptor 5 after toner transfer uniform over the surface of the photoreceptor, and lowers the potential for the next operation of the cleaning device. This is to ensure that. The static eliminator 22 is also fixed to the photoconductor block frame 24 at a predetermined distance from the photoconductor 5 . In the cleaning device 23, a cleaning blade 23a comes into contact with the photoreceptor 5, thereby scraping off the toner remaining on the photoreceptor 5 and transporting it from a pipe 23b to a waste toner box (not shown). The pressure with which the cleaning blade 23a contacts the photoreceptor 5 must be maintained extremely accurately.
The nig device 23 is also fixed to the photoreceptor Glock frame 24 at a predetermined distance from the photoreceptor 5.

As explained above, except for the photoreceptor 5 and the black developing device 10,
The other devices are fixed at respective predetermined positions shown in the figure on the photoreceptor block frame 24, and the photoreceptor 5
．． Together with the black developing device 10, a photoreceptor block 52 is formed. Further, the photoreceptor block 52 is supported by a rail guide portion 24b formed on the photoreceptor block frame 24 so as to be slidable on a block rail 27 fixed to the main body frame 20. Therefore, as shown in FIG. 4, it is possible to take out the photoreceptor block 52 as one piece from the main body frame 20 and perform repair work.

FIG. 5 is a sectional view taken along the arrow line X--X in FIG. 3.

As shown in FIG. 5, the photoreceptor 5 includes a photoreceptor layer 5c formed on a cylindrical surface and a photoreceptor shaft hole 5 that fits into the photoreceptor shaft 25.
b, and a shaft hole boss 5a formed around the shaft hole 5b. Usually, the photoreceptor block 52 is attached to the main body frame 20.
When the photoconductor 5 is attached to the photoconductor 5, the shaft hole 5b of the photoconductor 5 is fitted into the photoconductor shaft 25 fixed to the main body frame 20, and the photoconductor 5 is rotated on the photoconductor shaft 25 by a drive source built into the main body frame. . The shaft hole boss 5a is connected to the photoreceptor block frame 24
It is configured to fit loosely into the boss guide hole 24a. As shown in FIG. 5, when the photoconductor block 52 is slightly pulled out from the main body frame 20, one of the photoconductor shaft holes 5b is fitted into the photoconductor shaft 25, but the other photoconductor shaft hole 5b is fitted into the photoconductor shaft hole 5b. is removed from the photoreceptor shaft 25, and instead, the shaft hole boss 5a is supported by the boss guide hole 24a.

Since the photoreceptor shaft 25 has a tapered surface 25a at its tip, when the photoreceptor block 52 is pushed toward the main body frame 20 from the state shown in FIG. 5, the photoreceptor shaft hole 5b is guided by the tapered surface 25a. and is fitted with the photoreceptor shaft 25, and positioned in this state, the above-described charger 6. Pre-transfer charger 21. Static eliminator 22. The distance to the cleaning device 23 is accurately maintained.

Further, as shown in FIG. 5, a hollow hole 25b is provided inside the photoreceptor shaft 25, and an electric heater 29 is mounted therein.

Various characteristics of the photoreceptor 5, such as charging characteristics and sensitivity, vary depending on temperature, but when creating a color image, color reproducibility changes due to changes in the characteristics of the photoreceptor. Therefore, the electric heater 29 is used to always maintain the temperature of the photoreceptor at a constant value so that the characteristics of the photoreceptor do not fluctuate. In the embodiment of the present invention, the electric heater 29 is provided inside the photoreceptor shaft 25 fixed to the main body frame 20, so there is no need to remove the electric heater 29 when pulling out the photoreceptor block 52 for repair work. This makes repair work easier.

As described above, in the color image forming apparatus according to the embodiment of the present invention, the color developing devices 7, 8, and 9 are combined into one color developing block 51, and the black developing device 10 and other image forming elements are combined into one block. Since the photoreceptor blocks 52 are assembled into blocks, the weight of each block can be reduced. Therefore, each block can be easily pulled out from the main body frame 20 during repair work. In addition, by separating the color developing device and black developing device into blocks as described above,
When pulling out the black developing device 10, which is often repaired, do not pull out the color developing devices 7, 8, 9 that are not needed. can also be minimized.

Furthermore, since the frequently used black developing device 10, photoreceptor 5, and other image forming elements are combined into one block, the positional accuracy of the photoreceptor 5 and the black developing device 10, and the It is now easier to maintain positional accuracy with the imaging element.

This makes it possible to obtain stable image reproducibility. Although the color developing block 51 is a separate block from the photoreceptor 5, the color developing devices 7°8.9 are not individually fixed to the main body frame 20, but are collectively positioned as the color developing block 51. Therefore, it is easy to maintain positional accuracy with respect to the photoreceptor 5.

Furthermore, since the electric heater 29 is installed inside the photoreceptor shaft 25 fixed to the main body frame 20, fluctuations in the characteristics of the photoreceptor 5 can be reduced.

This makes it possible to obtain stable image reproducibility. Furthermore, even if the photoreceptor block 52 is removed during repair work, the electric heater 29 remains fixed to the main body frame 20, making the repair work easier.

Effects of the Invention As is clear from the above embodiments, according to the present invention, color developing devices are combined into one block, black developing devices and other image forming elements are combined into one block,
Furthermore, an electric heater is installed inside the photoreceptor shaft fixed to the main body frame, making it possible to easily pull out the necessary image forming elements from the main body frame during repair work, and making it possible to mix color toner and black toner. Contamination with foreign matter can be minimized. Furthermore, it becomes easy to maintain positional accuracy between the photoreceptor and the developing device and other image forming elements, and stable image reproducibility can be obtained. Furthermore, since the electric heater is mounted inside the photoreceptor shaft fixed to the main body frame, it is possible to maintain the photoreceptor characteristics constant, and image stability can be made more stable.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrophotographic color copying machine using a color image forming apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a color image block, and FIG. 3 is a sectional view of a photoreceptor block.
Figure 4 is a perspective view of the color developing block taken out from the main body frame and the photoreceptor block pulled out;
The figure is a cross-sectional view of the photoreceptor block along the arrow X--X line in FIG. 3, and FIG. 6 is a cross-sectional view of an electrophotographic color copying machine using a conventional color image forming apparatus. 4... Laser beam (light source), 5...
Photoreceptor, 6... Charger, 7... Yellow developer, 8... Magenta developer, 9...
... Cyan developer, 10... Black developer, 20.
... Main body frame, 21 ... Pre-transfer charger (pre-transfer device), 22 ... Static eliminator, 23.
... Cleaning device, 25 ... Photoreceptor shaft, 51 ... Color developing block, 52 ...
...Photoconductor block. Name of agent: Patent attorney Haruaki Ogata and 2 other masterpieces: 2. To the fourth prisoner ＼

Claims (2)

[Claims] (1) A photoconductor that rotates on a shaft fixed to the main body frame and can hold an electrostatic latent image; a light source that separates a color image into a plurality of primary color lights and irradiates the photoconductor; Multiple developing devices compatible with multiple primary colors and black, a charger placed around the photoreceptor, a pre-transfer device, a static eliminator,
It has a cleaning device, picks up the plurality of color developing devices except for black in a position facing the photoconductor so that they can be moved toward and away from the photoconductor, and can be attached to and detached from the main body frame in the direction of the rotation axis of the photoconductor. the color developing block, the charger,
A color image forming apparatus comprising a photoconductor block in which a pre-transfer device, a static eliminator, a cleaning device, and the black developing device are mounted at a position facing the photoconductor, and the photoconductor block is detachable from the main body frame in the direction of the rotation axis of the photoconductor. Device. (2) The color image forming apparatus according to claim (1), further comprising an electric heater installed inside the photoreceptor shaft fixed to the main body frame.