JPH05313423A - Color image forming device - Google Patents

Abstract

PURPOSE:To make a color image forming device compact and simple in structure and to facilitate the maintenance thereof. CONSTITUTION:A process cartridge 30 is incorporated with a photosensitive drum 1, respective developing units 4-7, and a cleaning device 8 so as to take out the cartridge from a device main body, as one body through a guiding rail 100, and simultaneously, respective toner hoppers 40-70 and a waste toner box 80 are supported in front of the cartridge 30. Further, an electrifier having both power sources for electrification and a transfer is adopted, thereby a toner carrying mechanism and electrical equipments are simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a format in which a single color image is superposed on an image forming body to form a color image by rotating the image forming body a plurality of times, and the color image is transferred onto a transfer paper for recording. The present invention relates to a color image forming apparatus.

[0002]

BACKGROUND OF THE INVENTION Many methods and apparatuses have been proposed for obtaining a color image using electrophotography. For example, JP-A-61
As disclosed in Japanese Patent Laid-Open No. -100770, a latent image is formed and developed on a photosensitive drum, which is an image forming body, according to the number of color separations of an original image, and the latent image is transferred to a transfer drum each time the image is developed. There is a method in which a multicolor image is formed on the upper surface and then transferred onto a transfer material to obtain a color copy. The device by this method is
Since it is necessary to provide a transfer drum having a size capable of transferring the image of another one sheet of the photosensitive drum onto the peripheral surface thereof, it is inevitable that the apparatus has a large size and a complicated structure.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-149972, latent images are formed and developed on the photosensitive drum in accordance with the number of separated colors of the original image, and the latent image is formed on the transfer material at each development. There is a method of transferring to to obtain a multicolored color copy. With this method, it is difficult to accurately superimpose multicolor images, and it is impossible to obtain a good color copy.

Further, a latent image is formed on the photosensitive drum in accordance with the number of separated colors of the original image and development with color toner is repeated, and the color toner images are superposed on the photosensitive drum and then transferred to obtain a color image. There is a way. The basic process of this multicolor image formation is described in Japanese Patent Application Laid-Open No. 60-75850
60-76766, 60-95456, 60-95458, 60-15847
It is disclosed in Japanese Patent Publication No. 5 and the like. The method of superposing a color toner image on the photoconductor has a feature that a high quality color image can be obtained.

[0005]

However, even in this method, the photosensitive drum needs to be large enough to accommodate the maximum image width, and a plurality of developing devices, cleaning devices, etc. are arranged on the peripheral surface thereof. Therefore, the device becomes large and the structure becomes complicated, so that the workability of maintenance cannot be avoided.

As a result of solving and improving this point, the present invention provides
It is an object of the present invention to provide a color image forming apparatus having a compact volume and good workability for maintenance by unitizing the equipment and improving the layout.

[0007]

The above-mentioned object is to provide a color image forming apparatus for transferring a color toner image formed by repeating charging, image exposure and development on a drum-shaped image forming body onto a transfer material. The formed body and the developing means are housed in a process cartridge which is attached to and detached from the apparatus together with a cleaning means arranged adjacent to the developing means, and the image exposure means is provided between the charging means and the cleaning means which also serve as transfer means. And a color image forming apparatus.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a color image forming apparatus according to the present invention. Reference numeral 1 is a photosensitive drum which is a drum-shaped image forming member and is driven to rotate in the direction of the arrow by the power of the main body of the apparatus. It

Reference numeral 2 is a charging device which also serves as transfer means, 3 is a laser writing system unit, 4 to 7 are developing units for accommodating developers of specific colors, and 8 is a cleaning device.
9 is a fixing device.

The developing units 4, 5, 6 and 7 are arranged along the peripheral surface of the photosensitive drum 1 and contain, for example, yellow, magenta, cyan and black developers respectively, and serve as the drum peripheral surface. The developing sleeves 4A, 5A, 6A, and 7A that maintain a predetermined gap are provided, and have a function of visualizing the latent image on the photosensitive drum 1 by a non-contact reversal developing method. Unlike the contact development, the non-contact development has an advantage of not giving resistance to the rotation of the photosensitive drum 1.

The blade 8 of the cleaning device 8
A is kept at a position apart from the peripheral surface of the photosensitive drum 1 during image formation, and is pressed against the peripheral surface of the photosensitive drum 1 as shown only during cleaning after image transfer.

The color image forming process by the color image forming apparatus is performed as follows.

First, the formation of a multicolor image according to this embodiment is performed according to the following image forming system. That is, the data obtained by the color image data input unit in which the image sensor scans the original image is processed by the image processing unit to create image data, which is once stored in the image memory. Next, the image data is taken out at the time of recording and input to the recording unit, for example, the color image forming apparatus shown in FIG.

That is, when a color signal output from an image reading apparatus separate from the color image forming apparatus is input to the laser writing system unit 3, a semiconductor laser (not shown) is provided in the laser writing system unit 3. The laser beam generated in 1 is rotationally scanned by the polygon mirror 3B rotated by the drive motor 3A, the optical path is bent by the mirror 3D via the fθ lens 3C, and the photoconductor drum 1 previously charged by the charger 2 is charged. Is projected onto the peripheral surface to form a bright line.

The charging device 2 has a built-in charging electrode which also serves as a transfer electrode. When a signal to start image formation is input to the control section by operating the copy button as shown in FIG. 3, the changeover switch is operated. The charging power source is turned on and a charging voltage is applied to the photosensitive drum 1. At that time, the transfer power is OFF
Is switched to.

On the other hand, when the scanning is started, the beam is detected by the index sensor, the modulation of the beam by the first color signal is started, and the modulated beam scans the peripheral surface of the photosensitive drum 1. Therefore, a latent image corresponding to the first color is formed on the peripheral surface of the photosensitive drum 1 by the main scanning by the laser beam and the sub-scanning by the rotation of the photosensitive drum 1.

This latent image passes under the blade 8A of the cleaning device 8 which is separated from the peripheral surface of the photosensitive drum 1, and is developed by the developing device 4 containing the yellow (Y) toner in the developing means. In the non-contact state, reversal development is performed to form a yellow toner image on the drum peripheral surface. The toner image obtained is held on the peripheral surface of the drum and enters the next image forming cycle.

That is, the photoconductor drum 1 is recharged by the charger 2, and then the second color signal output from the signal processing unit is input to the writing system unit 3 to obtain the above-mentioned first color signal. In the same manner as above, writing is performed on the drum peripheral surface to form a latent image. This latent image is subjected to reversal development in a non-contact state by the developing device 5 which contains magenta (M) toner as the second color.

This magenta (M) toner image is formed in the presence of the previously formed yellow (Y) toner image.

Reference numeral 6 denotes a developing device containing cyan (C) toner, which forms a cyan (C) toner image on the drum peripheral surface based on a control signal generated by a signal processing section.

Further, 7 is a developing device containing black toner, which is formed by superimposing a black toner image on the peripheral surface of the drum by the same process.

DC or further AC bias is applied to the sleeves of the developing devices 4, 5, 6 and 7, and jumping development is performed by a one-component or two-component developer which is a developing means, so that the substrate is The reversal development is performed on the grounded photoconductor drum 1 in a non-contact manner.

Thus, the color toner image formed on the peripheral surface of the photosensitive drum 1 by the four revolutions is carried out from the paper feed cassette 10 by the charger 2 which also functions as the transfer means, and is supplied by driving the timing roller 11. Transferred on paper Transferred on paper.

That is, the timing roller from the control unit
Before and after the drive signal of 11, the changeover switch shown in FIG. 3 is actuated to turn on the transfer power supply to the charger 2, the transfer voltage is applied to the transfer paper, and the toner image on the photosensitive drum 1 is transferred. It At that time, the charging power source is switched off.

The transfer paper on which the toner image has been transferred is separated from the peripheral surface of the photosensitive drum 1 and conveyed to a fixing device 9 via a suction type conveyance belt 12 to fuse the toner image and then onto a tray 13. Is discharged.

On the other hand, the photosensitive drum 1 from which the transfer paper is separated
Is the blade 8A of the cleaning device 8 at the fifth lap
The residual toner is removed / cleaned by receiving the pressure contact of No. 1, and the circuit is rotated once to be charged again by the charger 2 to start the process of the next copy cycle.

FIG. 4 is a time chart showing the color image forming process described above. The monochrome image forming process is completed by two revolutions of the photosensitive drum 1. However, in any image forming process, an image is formed. At the time of transfer, since the blade 8A of the cleaning device 8 is separated from the peripheral surface of the photosensitive drum 1, the drum rotates smoothly without causing uneven rotation, etc., and the image is transferred onto the transfer paper in a good image quality state. It becomes possible to do.

The photosensitive drum 1, the developing devices 4, 5, 6 and 7 arranged on the peripheral surface thereof and the cleaning device 8
Are housed in the apparatus main body in a state of being integrated and integrated in the process cartridge 30.

As shown in FIG. 2, the process cartridge 30 has toner hoppers 40, 50, 60 and 70 for supplying toner to the developing devices on the front surface thereof, and a waste containing the toner collected by the cleaning device 8. The toner box 80 is attached and integrally supported so that toner can be replenished and waste toner can be stored even during the image forming process operation. By unitizing the image forming unit in this way, the structure of the apparatus can be simplified and the volume can be made compact.

Both sides of the process cartridge 30 are supported by movable rails of a pair of guide rails 100 fixed to the main body of the apparatus, and after the door of the apparatus (shown by a chain double-dashed line) is released, the handle It can also be pulled out to the front side of the device via 30A and further removed. At this time, the gear G1 at the shaft end of the photosensitive drum 1 similar to that shown in FIG. 1 is automatically released from meshing with the drive gear G0 on the apparatus main body side, and by mounting it, the power from the apparatus main body side is removed. Is transmitted to the process cartridge 30.

By pulling out the process cartridge 30, the paper feeding / conveying surface of the transfer paper is opened widely, and further, the respective parts of the image forming section including the photosensitive drum 1 can be taken out of the apparatus. It will be easy to remove jammed paper or maintain the equipment.

[0032]

As described above, according to the present invention, a color image forming apparatus having a simple structure, good workability in maintenance, compact size, and automatic handling such as replenishment of toner can be provided.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a process cartridge loaded in the apparatus.

FIG. 3 is a block circuit diagram showing power supply switching in the charger.

FIG. 4 is a time chart of image formation by the apparatus.

[Explanation of symbols]

 1 photoconductor drum 2 charging (transfer) device 3 laser writing system unit 4, 5, 6, 7 developing device 8 cleaning device 9 fixing device 10 paper feed cassette 30 process cartridge 40, 50, 60, 70 toner hopper 100 guide rail

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisao Sato 2970 Ishikawacho, Hachioji City, Tokyo Konica Stock Company

Claims (2)

[Claims] 1. A color image forming apparatus for transferring a color toner image formed by repeating charging, image exposure and development on a drum-shaped image forming body to a transfer material, wherein the image forming body and the developing means include the developing means. And a cleaning means disposed adjacent to the cleaning means, which is housed in a process cartridge that is attached to and detached from the apparatus, and the image exposing means is disposed between the charging means also serving as a transfer means and the cleaning means. Color image forming apparatus. 2. The color image forming apparatus according to claim 1, wherein the developing means is integrated with a toner supply hopper.