JPH09197757A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the position of plural developing units in contact with the fixed developing regions on the peripheral surface of a photoreceptor drum, without causing distortion and deformation, respectively. SOLUTION: This color image forming device is constituted so that a pair of guiding pins P provided projectingly on the front and rear side surface of a developing unit 13(C) respectively are slidably engaged with guiding holes H provided in a developing frame 1300 and the guiding pins P are slid from horizontal parts to inclined parts in the guiding holes H by the repulsion of a compression coil spring S. Thus, in the developing unit 13(C), a butting roller 130A possessed by a developing sleeve 130 is moved toward a normal ON with respect to the periphery of a drum 10 from a horizontal direction, to come into contact with the peripheral surface of the drum, so that the developing sleeve 130 is positionally set in the fixed developing region, without the fear of the occurrence of the distortion and deformation.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In a color image forming apparatus of a type in which development of toner images of respective colors is started during one rotation of an image forming body, the image forming body having a relatively small diameter is not restricted by the size of an image to be formed. Although it is a color image forming apparatus that can be used, and as a result, can form a color image at high speed, it is advantageous in that it has a compact volume and at the same time is easy to assemble and maintain other developing means. There is.

[0003]

However, each developing means is
The shape is thin due to the plurality of arrangements facing the peripheral surface of the image forming body, and in order to prevent toner leakage and connection with the drive mechanism, all of them maintain a horizontal posture. Contacting the peripheral surface of the image forming body, therefore, if the diameter of the image forming body is small, a part of the developing means will contact the peripheral surface of the image forming body in an oblique direction. There is a possibility that the image may be deformed, so-called kinked, the developing conditions may be changed, and further harmful vibration may be caused to disturb the image to be developed.

[0004] The present invention has solved and improved the above points,
It is an object of the present invention to provide a color image forming apparatus in which any of a plurality of developing means can be positioned so as to be in vertical contact with the peripheral surface of an image forming body.

[0005]

The above object is to provide a plurality of charging means, image exposing means and developing means on the peripheral surface of an image forming body, and to charge and image expose during one rotation of the image forming body. In the color image forming apparatus, in which the toner images of multiple colors are formed on the image forming body by superposing and repeating the development and then the toner images are collectively transferred to a transfer material, the image forming body forms a drum image. The present invention is achieved by a color image forming apparatus, characterized in that the developing means is positioned in contact with the peripheral surface of the drum-shaped image forming body in the normal direction.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and function of a color image forming apparatus of the present invention will be described with reference to the embodiment shown in FIG.

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

Reference numeral 11 denotes a scorotron charger, which performs a charging operation on the above-described organic photoconductor layer of the photoconductor drum 10 by means of a grid held at a predetermined potential and corona discharge by a discharge wire, so that the photoconductor drum 10 is charged. Such a potential is applied.

Reference numeral 12 is an exposure optical system composed of LEDs and SELFOC lenses arranged in the axial direction of the photosensitive drum 10, and image signals of respective colors read by a separate image reading device are sequentially taken out from the memory. And is input as an electric signal to each of the exposure optical systems 12 described above.

Reference numerals 13Y to 13K denote developing units for accommodating yellow (Y), magenta (M), cyan (C) and K (black) developers, respectively, each having a predetermined gap with respect to the peripheral surface of the photosensitive drum 10. The developing sleeve 130 rotates in the same direction while maintaining the above.

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

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

The original image is temporarily stored in an image reading device, which is separate from this device, as an image 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. Are stored and stored in.

When the image recording is started, the photosensitive drum driving motor is started to rotate the photosensitive drum 10 in the clockwise direction, and at the same time, the charging action of the charger 11 (Y) starts to apply the potential to the photosensitive drum 10. .

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

The latent image is reversely developed by the developing device 13 (Y) with the developer on the developing sleeve in a non-contact state, and a yellow (Y) toner image is formed 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 charger 11 (M), and the second color signal of the exposure optical system 12 (M), that is, Exposure is performed by an electric signal corresponding to the magenta (M) image signal, and non-contact reversal development by the developing device 13 (M) causes a magenta (M) toner image on the yellow (Y) toner image. Will be sequentially stacked.

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

Photoreceptor drum 1 by each of these exposure optical systems
The exposure of the organic photosensitive layer of No. 0 is performed from the inside of the drum through the above-mentioned transparent substrate. Therefore, the exposure of the images corresponding to the second, third, and fourth color signals is performed without any influence from the previously formed toner image, and the same exposure as the image corresponding to the first color signal is performed. It is possible to form an electrostatic latent image. Further, during the developing action by each developing device, a developing bias in which a direct current or an alternating current is applied to the developing sleeve 130 is applied respectively, and jumping development is performed by the one-component or two-component developer accommodated in the developing device, thereby making it transparent. Photoreceptor drum 1 with conductive layer grounded
Non-contact reversal development is performed on 0.

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

The transfer sheet on which the toner image has been transferred is separated from the drum peripheral surface by removing the charge in the static eliminator 14B, and the toner is fused by the fixing device 17, and then the upper part of the device is passed through the paper discharge roller 18. Will be ejected onto the tray.

On the other hand, the photosensitive drum 10 from which the transfer paper is separated
The cleaning device 19 removes and cleans residual toner to continue formation of a toner image of a document image, or temporarily stops to form a toner image of a new document image.

The color image forming apparatus in which the exposure optical system 12 is housed inside the transparent photoconductor drum 10 has been described above. However, the color image forming apparatus of the present invention has the exposure optical system as a photoconductor. Also included is a device that is placed facing the outer circumference of the drum.

An embodiment of the present invention will be described with reference to FIGS.

Each of the developing devices 13 is shown in FIG. 2 by effectively utilizing the space on the peripheral surface of the photosensitive drum 10 so that the developing device 13 can be easily attached / detached together with the transfer device 14A and the cleaning device 19 at the time of assembly and maintenance. As such, they are arranged in good balance.

As a result, with respect to the horizontal plane MM passing through the rotation center O of the photosensitive drum 10, the developing devices 13 (Y) and 13
(K) is located at a position such that each of them has a small angle such as θ1 or θ2.
(C) is set in contact with the peripheral surface of the photoconductor drum 10 at a relatively large angle such as θ3 or θ4.

FIG. 3 is a sectional view showing a common structure of the developing devices 13. The toner replenished in the developing device 13 is a two-component developer due to the rotation operation of the pair of stirring screws 131 in opposite directions. In the case of use, the toner and the carrier are mixed and sent to the supply roller 132 as a developer having a uniform toner component, and attracted by the magnet body fixed inside the peripheral surface of the rotating developing sleeve 130. The developer on the developing sleeve 130 is further made to have a predetermined layer thickness by the layer thickness regulating member 133 and is conveyed to the developing area D on the peripheral surface of the photosensitive drum 10. In the developing area D, the abutting rollers 130A provided on both sides of the developing sleeve 130 come into contact with the photosensitive drum 10, and a prescribed gap is created between the photosensitive drum 10 and the developing sleeve 130.

Developing sleeve 1 for the developing area D
The position setting of 30 will be described with reference to FIG. 4 by taking the case of the developing device 13 (C) as an example.

The developing device 13 (C) has a pair of guide pins P projecting symmetrically on each of the front and rear side surfaces, and the guide pins P are fixed to the main body of the developing unit 13.
00 is provided in a groove-shaped guide hole H slidably, and by the repulsive force of a compression coil spring S sandwiched between the rising surface of the developing rack 1300 and the photosensitive drum 10,
It is designed to be urged to the peripheral surface side.

Each of the guide holes H is composed of a horizontal portion and a sloped portion parallel to the angle .theta.4 described above. At the initial stage of biasing by the compression coil spring S, each guide pin P as shown in FIG. Is initially guided in the horizontal direction toward the peripheral surface of the photoconductor drum 10 by sliding on the horizontal portion, but at the final stage of urging, as shown in FIG.
As shown in (b), each guide pin P slides on the inclined portion so that the abutting rollers 130A provided on both side ends of the developing sleeve 130 are in the normal direction, that is, the normal line ON with respect to the peripheral surface of the photosensitive drum 10. The developing sleeve 130 is abutted from the direction and is set in position with respect to a predetermined developing region D without being subjected to a twisting stress. The repulsive force of the compression coil spring S needs to be generated when the abutting roller 130A comes into contact with the photosensitive drum 10, and is compressed while each guide pin P slides in the horizontal portion. The coil spring S may not have a repulsive force.

On the condition that the developing device 13 (C) is kept in the horizontal state at the time of setting the position, as shown in FIG. 5, by providing the inclined portion only in the guide hole H on the developing sleeve 130 side, The abutting roller 130A can also be brought into contact with the normal line in the direction of ON. Although the guide hole H is shown as being divided into two guide holes in FIG. 5, it may be one continuous guide hole.

Further, other developing devices 13 (Y) and 13 (M)
And the developing device 13 (C) described above for 13 (K)
The position setting with respect to the peripheral surface of the photoconductor drum 10 is performed by the same means as in the case of, but the developing devices 13 (Y), 13
When the angle with respect to the horizontal line MM is extremely small as in (K), the developing sleeve 13 accompanying the contact of the abutting roller 130A.
Since the deformation and kinking of 0 are extremely small, the guide hole H does not need a sloping portion and the entire length is a horizontal portion, or the horizontal portion is eliminated and the entire length is a straight line with a slight inclination so that the guide hole H abuts in the normal direction. You can

[0033]

According to the present invention, each developing device is brought into contact with the peripheral surface of the photosensitive drum without distortion or deformation and is accurately arranged at a predetermined position. Therefore, it is possible to provide a color image forming apparatus capable of recording a high quality color image by performing various developing operations.

[Brief description of drawings]

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

FIG. 2 is a layout diagram of a developing device.

FIG. 3 is a cross-sectional configuration diagram of a developing device.

FIG. 4 is an explanatory view (No. 1) showing the position setting of the developing device.

FIG. 5 is an explanatory view (No. 2) showing the position setting of the developing device.

[Explanation of symbols]

 10 Photoconductor Drum 11 Scorotron Charger, Charger 12 Exposure Optical System 13 Developing Device 14A Transfer Device 14B Electrifier 15 Paper Feed Cassette 16 Timing Roller 17 Fixing Device 18 Paper Ejection Roller 19 Cleaning Device 20 Supporting Member 130 Developing Sleeve 130A Abutment Roller 131 Stirring screw 132 Paper feed roller 133 Layer thickness regulating member 1300 Developer support substrate, development rack D Development area S Compression coil spring P Guide pin H Guide hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayasu Onodera 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor ▲ Hama ▼ Tajuta 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation ( 72) Inventor Toshihide Miura 5-14-14 Midoricho, Koganei-shi, Tokyo

Claims (2)

[Claims] 1. A plurality of charging means, image exposing means and developing means are provided on the peripheral surface of the image forming body, and the charging, image exposing and developing are repeated during one rotation of the image forming body to form the image forming means. In a color image forming apparatus for forming a multicolor toner image on a body by superimposing the toner images, and transferring the toner images to a transfer material at once, the image forming body is a drum-shaped image forming body, Is set in contact with the peripheral surface of the drum-shaped image forming body in the normal direction, and the position is set. 2. The developing means is configured to be guided in the horizontal direction with respect to the drum-shaped image forming body and then to be brought into contact with the peripheral surface in the normal direction. Color image forming apparatus.