JPH02264979A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the maintainability by positioning a laser optical device with a laser outgoing port in an approximate center part and position fixing parts provided above and below the outgoing port by positioning it to make laser beam make incident against an image forming body from an approximate sideways direction and by positioning a developing device in a lower direction. CONSTITUTION:The laser optical unit 10 is of a compact constitution with a beam path deflected utilizing two pieces of mirrors M1 and M2, and the laser outgoing port and the position fixing members 21 above and below it are provided. When a unit attaching part 20 is traveled in the upper right direction of the diagram against the beam of a helical spring 23 by rotating a knob, engaging the position fixing member 11 of the unit 10 with the position fixing member 21, if knob is let go, with the power of the helical spring 23 a retaining part 201 is traveled to the left direction, and the unit 10 is pressured to the member 21 and the position is correctly fixed. Further, by rotating the knob, the unit 10 can be easily detached from a main body. Thus, the developing devices 33 to 36 can be positioned in the lower direction with the unit 10 provided freely attachable / removable, and the laser beam L is provided to make incidence against a drum 30 from the sideways direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image forming apparatus using electrophotography, and relates to an image forming apparatus that is miniaturized and unitized to improve maintenance performance.

[Conventional technology]

An electrophotographic image forming apparatus that forms full-color or monochrome images includes a charger that charges a photoreceptor drum, which is an image forming member, a developer that develops an electrostatic latent image on the photoreceptor drum with toner, and a photoreceptor drum. A transfer device or the like that transfers the upper toner image onto recording paper is disposed at the peripheral edge of the photoreceptor drum.

Of these, the full-color electrophotographic image forming apparatus has three or four developing units each containing yellow (Y), magenta (M), cyan (C) toner, and sometimes black (BK) toner. During the three or four rotations of the photoreceptor drum, each toner image of yellow, magenta, and cyan or black is formed on the photoreceptor drum, and this toner image is transferred to recording paper. I'm trying to get a full color image.

When using such an image forming method, the color image forming apparatus can be made compact by making three or four developing units thin and arranging them close to each other.

Japanese Unexamined Patent Publication No. 61-55661 proposes a color image forming apparatus using such an image forming method, using three lasers corresponding to three developing units; The photosensitive drum, the developing device, and the cleaning means are integrated into a unit and can be taken out from the main body of the apparatus.

Furthermore, Japanese Patent Application No. 62-320596 discloses a system in which one exposure device is used and the developing devices are placed one on top of the other, and the unit is made into a unit in the same manner and can be taken out from the main body of the device.

Said Japanese Unexamined Patent Publication No. 61-55661 and Japanese Patent Application No. 62-3
Although the color image forming apparatus described in the specification of No. 20596 contributes to improved maintainability, the developer is likely to spill or get mixed in when the unit is inserted or removed.

Furthermore, in a color image forming apparatus that uses a transfer drum to transfer each color toner image to a recording paper, an example in which the photosensitive drum and its surroundings are formed into a unit is described in Japanese Patent Application Laid-Open No. 72159/1983.

[Problems to be Solved by the Invention] However, in the color image forming apparatus described in JP-A-58-72159, (1) the image forming section extends not only around the photoreceptor drum but also the transfer drum; .

(2) The circumferential speed and gap between the photosensitive drum and the transfer drum must be maintained with high accuracy.

(3) A release mechanism is required to take out the photoreceptor drum.

As mentioned above, in a color image forming apparatus using a transfer drum, not only is the mechanism complicated and expensive as described in (2) and (3) above, but also the mechanism is complicated and expensive, as in a monochrome image forming apparatus that does not require a transfer drum. There are problems in that the image forming means is not concentrated around the photoreceptor, and the advantages of unitizing the image forming section (process unit) cannot be fully obtained.

The present invention solves these problems and provides a cartridge structure in which the developing unit, image forming body, and cleaning means are integrated, or two of them are integrated and the remaining one is independently insertable and removable. This improves maintainability, and when multiple developing units are combined into a unit and the process unit is inserted into and removed from the main body of the apparatus, the developer may spill outside or the developer may leak into other developers. It has a structure that prevents it from entering the image forming apparatus, and the laser optical unit, which is the image exposure means, is made into a unit and has a structure that allows it to be inserted into and removed from the main body of the image forming apparatus. An object of the present invention is to provide an image forming apparatus with improved maintainability.

[Means to solve the problem]

The purpose is to install a laser optical unit in which a laser beam exit port is located approximately at the center and a positioning portion is provided above and below the exit port, and the laser beam is directed from the exit port in a substantially lateral direction relative to the image forming body. This is achieved by an image forming apparatus characterized in that the positioning section is configured to abut and position positioning members provided at upper and lower positions of the apparatus main body so that the light enters the apparatus body.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the main configuration of an embodiment of the present invention, and FIG. 2 is a block diagram showing the image forming system of this embodiment.

Formation of the multicolor image in this embodiment is accomplished according to the image forming system shown in FIG. That is, the image signal obtained by the color image data input section (FIG. 2 (a)) in which the image sensor scans the original image is input to the image data processing section (
Image data is created through arithmetic processing in FIG. 2 (b)), which is then stored in the image memory (FIG. 2 (c)). Next, the image data is taken out during recording and sent to the recording section (second
For example, the laser beam is inputted to the laser optical unit of the multicolor image forming apparatus shown in FIG. 1, which is shown in FIG.

In recording by the multicolor image forming apparatus, first, the photosensitive drum 30, which is an image forming body having a photoconductive photosensitive layer that rotates in the direction of the arrow, is neutralized by a static eliminating lamp 31, and then charged by a scorotron type charger 32. Various charges are applied.

Next, this charged surface is illuminated by laser light modulated by image data retrieved from the image memory (FIG. 2 (c)) via the laser optical unit 10.
The photoreceptor drum 30 is imagewise exposed from the lateral direction to form an electrostatic latent image.

This electrostatic latent image is developed in a non-contact manner by a reversal development method using developing devices 33, 34 and 35, 36 which contain a two-component developer and are located below the photoreceptor drum 30, thereby forming a toner image. Ru. For example, in this image forming process, the photoreceptor drum 3 is used for each color in the order of yellow, magenta, cyan, and black.
0 is repeated once, and a multicolor toner image in which the toner images of each color are superimposed is formed. This multicolor toner image is
After being charged by the pre-transfer charger 38 to facilitate transfer, the transfer belt 50 rotates from before the start of transfer and brings the transfer belt 50, which had been retracted during image formation, into contact with the photoreceptor drum 30. A transfer charge having a polarity opposite to that of the toner is applied to the transfer belt 50 by a transfer charger 65 . On the other hand, feeding means 41. The recording paper P is fed via the paper feed roller 42 and the timing roller 43 at the same timing as the image formation, and is transferred while being sandwiched between the photoreceptor drum 30 and the transfer belt 50 .

The recording paper P onto which the multicolor toner image has been transferred is transferred to the transfer belt 5.
0, the image is separated from the photosensitive drum 30 and conveyed to the fixing device 6, where it is heated and fixed, and a completed copy image is formed and is discharged from the device.

On the other hand, after the photosensitive drum 30 from which the recording paper P has been separated from the drum circumferential surface has been neutralized by the pre-cleaning static eliminator 39, the abrasive brush 37a of the cleaning device 37, which had been retracted during image formation, comes in contact with the remaining toner. is removed, and after the removal is completed, it is separated from the drum circumferential surface again and prepared for the next image formation.

The upper part 1a of the casing 1 is rotatable about the hinge lb, and the upper part can be opened to facilitate maintenance. Further, lc is a manual feed stand on which recording paper for manual feed is placed.

A process cartridge 3 for carrying out the above-described process is provided in the main body of the apparatus as an independent process unit, suspended from the main body by a pair of guide members 4 on the left and right, so that it can be easily taken out and installed. . That is, a photosensitive drum 30 is located approximately in the center of the process cartridge 3, and a charging device 32, developing devices 33 to 36, and a cleaning device 37 are arranged around the circumferential surface of the photosensitive drum 30.
bearings are supported or removably attached to the process cartridge 3, respectively. In particular, the developing devices 33 to 36 are provided symmetrically below the center, and the cleaning device 37 is provided downstream of the developing devices 33 to 36. The arrangement order of the charger 32, the developers 33 to 36, the cleaning device 37, etc. is not limited to this embodiment.
The cleaning device 37 may be disposed upstream of the developing devices 33 to 36. FIG. 8 shows an embodiment of an image forming apparatus having such an arrangement.

By holding the cartridge 3 in a suspended state with respect to the substrate of the main body in this way, the photoreceptor drum 30, the developing device 33 to
The vibrations and shocks transmitted to the cleaning device 36 or the cleaning device 37 are greatly alleviated and absorbed, and even if some vibrations and shocks are transmitted, each equipment will be subjected to various vibrations and shocks, which will cause a major hindrance to image formation. It is designed so that it never comes.

FIG. 7 is a developed view of a laser optical unit IO used as an exposure device. A semiconductor laser 191 of the laser optical unit 10, which is a laser writing section, is provided with a laser drive circuit 190.
Image data from the image memory described above is input to modulate the laser beam. A laser beam, which is a modulated laser beam, is rotated and scanned by a polygon mirror 112 rotated by a drive motor 111 (not shown in FIG. 7), passes through an fθ lens 195, and is bent by a mirror (not shown) to form a cylindrical optical path. Through the lens 196, the peripheral surface of the photosensitive drum 3o, which is a pre-charged image forming body, is scanned to form a latent image.

On the other hand, when scanning is started, the laser beam L is reflected by the mirror 197; the laser beam L is detected by the index sensor 198, the modulation of the laser beam L by the image data of the first color is started, and the modulated laser beam L is The circumferential surface of the rotating photosensitive drum 30 is scanned.

Therefore, the main scanning by the laser beam and the photosensitive drum 30
An electrostatic latent image of the first color is formed on the circumferential surface of the photosensitive drum 30 by the sub-scanning caused by the rotation of the photosensitive drum 30 . This latent image is developed by a developing device 33 loaded with, for example, yellow toner among the developing means to form a visible toner image. The obtained toner image, while being held on the photosensitive drum 30, passes under the cleaning device 37 and the transfer belt 50, which are separated from the circumferential surface of the photosensitive drum 30, and enters the next copy cycle.

That is, the photoreceptor drum 30 is charged again by the charger 32, and then the second color image data output from the image memory is input to the laser optical unit 10, and the image data of the first color is Similarly, photoreceptor drum 3
Writing is performed on the zero circumferential surface and a latent image is formed. This latent image is developed by a developer 34 loaded with toner of a second color, for example magenta. This magenta toner image is formed to be superimposed on the previously formed yellow toner image.

Thereafter, in the same manner, a cyan toner image and a black toner image are exposed to light by the laser optical unit IO, and then the developing device 35
, 36 and are formed in a superimposed manner. Direct current and sometimes alternating current bias voltages are applied to the developing sleeves of these developing units 33 to 36, and non-contact jumping development is performed on the photosensitive drum 30 using the two-component developer.

FIG. 3 is a side view showing the unit mounting of the laser optical unit IO, FIG. 4 is a plan view showing the cross section taken along line A-A in FIG. 3, and FIGS. FIG. 2 is a cross-sectional view showing a configuration of a laser optical unit IO shown in a developed view as a unit using a mirror.

In the figure, reference numeral 11 indicates positioning parts provided above and below on the photosensitive drum 30 side of the case of the laser optical unit 10;
0 is a unit mounting member provided slidably on the main body board, 201 is a holding portion for holding the laser optical unit 10, and 202 is a cam receiver bored at one end of the mounting member 20. The hole 203 is a long hole that provides guidance during sliding.
21 is a positioning member erected on the main body board of the image forming apparatus; 23 is a helical spring that pulls the member 20 toward the positioning member 21; 24 is a spring hook pin erected on the main body board; 25 is the main body A guide bin installed on the board,
26 is an eccentric cam, and 27 is a knob attached to the shaft of the eccentric cam 26.

Rotate the knob 27 to move the unit mounting member 20 to the right in the drawing against the force of the helical spring 23, and move the positioning part 11 of the laser optical unit 10 to the positioning member 2.
Seven helical springs 23 that fit into I and release the knob 27
The holding portion 201 is moved to the left by the force, and the laser optical unit 10 is pressed against the positioning member 21 so that the position is determined correctly. Further, the laser optical unit 10 can be easily removed from the main body by rotating the knob 27.

In FIGS. 5 and 6, Ml, M2. M3 is a mirror, and the laser optical unit IO uses two mirrors Ml and M2, as shown in FIG. 5, and three mirrors Ml.

M2. Using M3, the optical path can be bent as shown in FIG. 6 to create a compact structure, and a laser beam exit opening can be provided near the center and positioning parts above and below the exit opening.

As described above, the laser optical unit IO can be freely inserted and removed, the laser beam can be incident on the photosensitive drum 30 from the side, and the developing devices 33 to 36 can be positioned below. It became possible.

〔Effect of the invention〕

According to the present invention, as explained above, the laser optical unit shown in FIG. By configuring the image forming body so that the light enters the image forming body from the exit port in a substantially lateral direction, and by configuring the developing unit to be located below, the laser optical unit can be inserted and removed, making inspection extremely easy. It is possible to improve maintenance efficiency by combining multiple developing devices into a unit, and when the process unit is inserted into and removed from the main body of the device, the developer may spill outside or the developer may be mixed with other devices. It has now become possible to provide an excellent, small-sized image forming apparatus that can prevent contamination in the developing device.

[Brief explanation of drawings]

1 and 8 are diagrams showing the main configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing the image forming system of this embodiment, and FIG. 3 is a side view showing the unit mounting member 20. Figure, 4th
The figures are a plan view showing the section taken along the line A-A in Figure 3, Figures 5 and 6.
The figure is a sectional view showing the configuration of the laser optical unit IO, and FIG. 7 is a developed view of the laser optical unit IO. I... Housing 3... Process cartridge 4... Guide member 6... Fixing device 10...
・Laser optical unit 20...Unit installation is done by member 21...Positioning member 30...Photosensitive drum 33-36...Developer 3
7...Cleaning device 50...Transfer belt L...
・Laser light (laser beam) P...Recording paper

Claims (1)

[Claims] A laser optical unit having a laser beam exit port located approximately at the center and positioning portions provided above and below the exit port is configured such that the laser beam enters the image forming body through the exit port from approximately lateral to the image forming body. An image forming apparatus characterized in that the positioning section is configured to contact and position positioning members provided at upper and lower positions of an apparatus main body.