JPH06138745A - Color image forming device - Google Patents

Abstract

PURPOSE:To achieve miniaturization, simplification and an improvement in operation quality in device maintenance by providing a transfer means which transfers a toner image to transfer paper at the top of one end of a belt-like intermediate transfer body. CONSTITUTION:The intermediate transfer belt 201 is arranged longitudinally, and a photosensitive drum 1 is in contact with the one surface of its middle position. A multicolor development device 100 is arranged opposite to the intermediate transfer belt 201 with the photosensitive drum 1 between them, that is, to one surface of the photosensitive drum 1. Further, at the top of the intermediate transfer belt 201, a secondary transfer bias roller 204 as the transfer means is arranged. A transfer sheet carrying means is constituted at the front and back parts of the device in the horizontal direction including the intermediate transfer belt 201. The secondary transfer bias roller 204 is controlled so as to be brought into contact with the intermediate transfer belt 201 and separated from it, and sheet feed means such as a sheet feed cassette 41, a sheet feed roller 42, a fixing unit 300 as a fixing means, etc., are provided perpendicular to the transfer means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus.

[0002]

2. Description of the Related Art The following technique is disclosed as an image forming apparatus using one intermediate transfer belt and one photoconductor belt.

(A). The peripheral ratio of the photosensitive belt and the intermediate transfer belt is set to 2: 1. The photoconductor belt is arranged horizontally, and a plurality of developing devices are arranged on the upper surface thereof. The intermediate transfer belt is arranged substantially orthogonal to one end of the photosensitive belt. The transfer paper path is placed below the intermediate transfer belt and the photoconductor belt (Japanese Patent Laid-Open No. 182766/1987).
SP4710785))).

(B). The photoconductor belt is placed vertically, a multicolor developing device is provided on one side thereof, a black-and-white developing device, a discharging charger, a cleaner, and a writing section are provided on the other side, and the intermediate transfer belt is disposed orthogonally at the bottom. The transfer paper conveyance path is located below the intermediate transfer belt (see Japanese Patent Application Laid-Open No. 4-5669).

(C). The peripheral length ratio between the photoconductor belt and the intermediate transfer belt is 2: 1. The photoconductor belt is arranged diagonally, and a plurality of developing devices are arranged on the upper surface. The intermediate transfer belt is arranged at the lowermost end surface of the photoreceptor belt, and the transfer paper conveying path is located below the intermediate transfer belt (see Japanese Patent Laid-Open No. 292156/1988).

(D). The peripheral length ratio between the photosensitive belt and the intermediate transfer belt is 1: 1. The photosensitive belt is arranged vertically, and a plurality of developing devices are arranged on one side surface of the photosensitive belt. The intermediate transfer belt is obliquely arranged on the uppermost end surface of the photosensitive belt, and the transfer paper conveyance path is located below the intermediate transfer belt (see Japanese Patent Laid-Open No. 3-249671).

(E). Place the photoconductor belt vertically,
A plurality of developing devices are installed on this one end surface. The intermediate transfer belt is horizontally arranged on the uppermost end surface of the photoconductor belt, and the transfer paper conveyance path is located above the intermediate transfer belt.
The intermediate transfer belt also serves as a conveyor belt (USP4
957676).

The following technology is disclosed as an image forming apparatus using one intermediate transfer belt and one photosensitive drum.

(F). A plurality of developing units are provided on the top of the photosensitive drum (see Japanese Patent Laid-Open No. 59-104673).

(G). An intermediate transfer belt (conveyance on transfer paper) is arranged near the top of the photosensitive drum, and a plurality of developing devices are arranged in the lower part (see USP 4935788).

(H). An intermediate transfer belt is arranged at the bottom of the photosensitive drum (see Japanese Patent Application Laid-Open No. 1-92771).

(I). An intermediate transfer belt is arranged at the bottom of the photosensitive drum, and a vertical slide developing device is arranged at one end (see Japanese Patent Application Laid-Open No. 1-246575).

(J). An intermediate transfer belt is arranged at the bottom of the photosensitive drum, and a plurality of developing devices are arranged at one end (see Japanese Patent Laid-Open No. 4-69676).

(K). An intermediate transfer belt is arranged at one end of the photosensitive drum.

[0015]

The above-mentioned conventional techniques have problems in downsizing of the image forming apparatus, simplification of the apparatus configuration, improvement of operation quality during maintenance of the apparatus, and the like.

Here, the operation quality includes, for example, the scattering and color mixing of the developer and toner, the exchangeability of the photoconductor and the intermediate transfer belt, and the like.

Therefore, it is an object of the present invention to provide a color image forming apparatus capable of downsizing the image forming apparatus, simplifying the apparatus configuration, and improving the operation quality during maintenance of the apparatus.

[0018]

In order to achieve the above object, the present invention has the following constitution.

(1). A drum-shaped image carrier is provided on one side surface of the belt-shaped intermediate transfer member placed in the vertical direction, and a rotary developing device is arranged on one side surface of the drum-shaped image carrier. A transfer means for transferring the toner image onto the transfer paper is provided at the uppermost portion (claim 1).

(2). In (1), as a transfer means from the belt-shaped intermediate transfer member to the transfer paper, a bias roll that is controlled so as to be able to come into contact with and separate from the belt-shaped intermediate transfer member is provided, and the bias roller is orthogonal to the transfer unit provided with the bias roller. In this way, a sheet feeding means, a fixing means, and a conveying means are provided (claim 2).

(3). In (1), the transfer paper conveying means is arranged so as to be orthogonal to the transfer means, and a laser for the drum-shaped image carrying body is provided above the drum-shaped image carrying body and the rotary developing device and below the transfer paper carrying means. A writing means is provided (Claim 3).

[0022]

The member with a high maintenance frequency is located at a position where the device can be easily opened, and the main constituent members are arranged closely.

[0023]

EXAMPLES First, an outline will be described. In the figure, the original image information converted into an electric signal by an image processing / controller (not shown) is image-exposed by the exposure light 3 onto the photosensitive drum 1 as a drum-shaped image carrier by the writing unit 30 by the laser. To be done.

The electrostatic latent image corresponding to the original is developed by each developing device of the multicolor developing device 100, which is a rotary developing device, and is supported by the supporting roller 205 in the intermediate transfer belt unit 200.
A toner image is formed on an intermediate transfer belt 201 as a belt-shaped intermediate transfer member rotatably supported by A, 205B and the like.

This toner image is transferred onto the transfer paper 40 by the transfer means section in which the secondary transfer bias roller 204 constituting the secondary transfer section 203 is arranged. After that, transfer paper 4
Reference numeral 0 passes through a fixing unit 300 as a fixing unit, and is discharged outside the machine as a print by a paper discharge roller 400.

During full-color printing, the known color image forming cycle for each color of yellow (Y), magenta (M), cyan (C), and black (BK) is sequentially repeated.

According to the present invention, each image forming unit and member required for image formation are selected and their proper arrangement is made. Particularly, each image forming unit and member around the photoconductor is properly arranged, so that the entire apparatus can be made compact and simple. , Low cost, high reliability, easy maintenance, easy attachment / detachment of photoconductor, intermediate transfer belt, developing device, etc., improvement of transfer paper transport performance and easy jam processing, It is intended to achieve both black and white and color image quality.

The main image forming units and members around the photosensitive drum include a photosensitive drum, a static eliminator, a charger, a cleaner, a developing device, an intermediate transfer device, and a writing section.

The intermediate transfer belt 201 is arranged in a vertical direction, and the photosensitive drum 1 is in contact with one side surface of the intermediate transfer belt 201 at an intermediate position.

A multicolor developing device 100 is arranged at a position facing the intermediate transfer belt 201 with the photoconductor drum 1 in between, that is, at one side surface of the photoconductor drum.

At the top of the intermediate transfer belt 201, a secondary transfer bias roller 204 as a transfer means is arranged. At the front and rear portions in the horizontal direction including the intermediate transfer belt 201, a transfer paper conveying unit is configured.

In such a structure, the transfer paper conveying system, which has a small empty space and a dense member structure, and has a high frequency of maintenance such as jams, is arranged on the upper part of the apparatus, and the intermediate transfer belt, the photosensitive drum, and the developing device. Also, maintenance from the side of the device is easy.

The secondary transfer bias roller 204 is controlled so as to come into contact with and separate from the intermediate transfer belt 201, and the sheet feeding cassette 41 and the sheet feeding roller 4 serve as a transfer sheet conveying system.
A fixing unit 30 serving as a sheet feeding unit and a fixing unit such as 2.
0, a registration roller 43 as a conveying means, a guide roller 44, etc. are arranged on a substantially horizontal line so as to be orthogonal to the transfer means. Such a configuration is suitable for efficient arrangement of members and easy maintenance.

The writing section 30 is arranged in a substantially horizontal shape above the photosensitive drum 1 and the multicolor developing device 100 and below the transfer sheet conveying means, and has a dense member structure.
Further, such a position is a position where the main writing unit, which is most susceptible to the image quality, is protected against contamination such as toner, dust, and dust inside the machine.

As the photoconductor of the photoconductor drum 1, a normal photoconductor is used, and a unit is formed into a magazine which is easy to handle when the photoconductor is replaced. The outer circumference of the photoconductor drum 1 is set to an integer ratio with the intermediate transfer belt 201. Further, the outer diameter of the support roller 205A that also drives and supports the intermediate transfer belt 201 is the outer diameter of the photoconductor drum 1. The size is an integer ratio with, which realizes the simplest driving with no positional deviation (color misregistration).

Since the charging device 2 and the static eliminator 6 are the largest causes of image unevenness due to contamination of corona wires, rollers, lamps, etc., their installation locations are separated from the developing device 100 and the photoconductor cleaner 5. It is necessary to set the position where toner, dust, dust, etc. do not reach the most.

The photoconductor cleaner 5 has a cleaning ability,
Uses the blade type, which has the best overall cost and reliability, and maximizes the weight of collected items such as cleaned toner, dust such as paper powder, and dust in order to maintain and maintain cleaning performance. It is preferable to use.

Further, if the toner or the like is detached from the cleaner when the photoreceptor cleaner 5 is detached from the image forming apparatus or when the photoreceptor drum is detached, the inside and outside of the machine will be contaminated, and it must be prevented as much as possible.

Therefore, in this embodiment, the photoconductor cleaner 5 is provided at one end of the photoconductor and is integrally provided with the recovery toner tank so as to satisfy the above requirements.

It is widely known that the developing system includes a one-component developing system and a two-component developing system. Since the one-component developing method does not have a carrier, there is an advantage that the agent concentration control and the agent agitation are unnecessary, and the apparatus is simple and compact.

There are two types of one-component developing systems, a magnetic toner type and a non-magnetic toner type. Among these, non-magnetic type toner having excellent color reproducibility is used for color.

For full-color image formation, three colors Y, M and C are used.
Due to color toner composition. Therefore, it is necessary that the developing, transferring, and fixing characteristics of the toners of the three colors are well balanced, and it is particularly desirable that the developing system and the toner prescription have the same characteristics. In this example, non-magnetic 1
The component development method is used.

The developing device is important in its installation position from the viewpoints of preventing scattering of toner and agents at the time of development and attachment and detachment and preventing mechanical damage to the photosensitive drum at the time of attachment and detachment. This is particularly important for those using a developing device. The arrangement of this example also meets this requirement.

The multi-color developing device 100 has a structure in which independent developing devices are accommodated in the rotating body for each color. The yellow developing device 101Y, the magenta developing device 101M, the cyan developing device 101C, and the black developing device 101BK have the same structure.

The developing sleeves 102Y, 102M, 102C and 102BK are the main members of each developing device.
Supply rollers 103Y, 103M, 103C, 103B
K, developing blades 104Y, 104M, 104C, 10
4BK, stirring members 105Y, 105M, 105C, 10
5BK etc.

In the multicolor developing device 100, the toner is carried to the developing sleeve 102 by the stirring member 105 and the supply roller 103. Further, it is thinned by the developing blade 104 and provided for development.

Switching of the developing device for each color is performed by rotational drive and control by a drive mechanism (not shown).

The intermediate transfer method according to this example is known as a transfer method capable of realizing a paper-free and full-screen image. In order to rationally realize the transfer paper conveyance quality and the operation quality when the transfer paper is jammed and the print stacker operation quality, the transfer paper is conveyed at the upper part of the machine body, that is, the intermediate transfer. Best is the top of belt 201.

Further, in the printer, the printing order is usually processed from the first page of the original, so that it is necessary to discharge and stock the printed product with the image side thereof facing downward, thereby improving the productivity and the operation quality during printing. Is important for securing

Therefore, the intermediate transfer belt 201 is connected to the transfer paper 4
It is most rational to set the retransfer position to 0 to the upper side of the photoconductor drum 1 and the image forming surface of the printed product downward.

In this example, while applying bias voltage to the transfer bias applying rollers 202A and 202B constituting the primary transfer portion 202, the toner images on the photosensitive drum are sequentially transferred.
Transferring onto the intermediate transfer belt 201.

While the transfer is being performed, the intermediate transfer belt cleaner 206 and the secondary transfer bias roller 204 are retracted to a position apart from the intermediate transfer belt 201 by a control means (not shown).

The transfer paper 40 in the paper feed cassette 41 is conveyed to the registration rollers 43 by the paper feed roller 42. At the time of manual paper feeding, the transfer paper 40 inserted from the manual paper feeding port 45 is conveyed to the registration roller 43 by the paper feeding roller 42.

At the time of manual feeding, the transfer paper 40 inserted from the manual feeding port 45 is conveyed to the registration roller 43 by the guide roller 44. The registration roller 43 is
The drive is controlled so that the leading edge of the transfer paper and the toner image on the intermediate transfer belt match.

The transfer of the toner image onto the transfer paper 40 is performed by applying a bias to the secondary transfer bias roller 204. The transfer paper after transfer is the fixing unit 3.
00, and the image is fixed when passing between the fixing roller 301 and the pressure roller 302.

The fixing device is based on hot roll fixing. A heater is built in the fixing roller 301, and a silicone oil coating device 305 is arranged around the heater. This silicone oil enhances the fixing performance during full color printing.

The secondary transfer bias roller 204 has both a transfer function and a transfer paper conveying function. In this example,
Since the transfer sheet is fed from the feeding to the discharging in the horizontal direction and the feeding distance can be made very short, high feeding quality can be secured.

The jam processing can be easily performed because the conveyance path is exposed by opening the upper cover 500. Also, it goes without saying that the machine body can be made very compact.

The intermediate transfer belt cleaner 206 cleans transfer residual toner and dust. The processed material by cleaning is carried to the waste toner tank by a known transfer member (not shown).

[0060]

As described above, according to the present invention, it is possible to provide a color image forming apparatus capable of downsizing the image forming apparatus, simplifying the apparatus configuration, and improving the operation quality during maintenance of the apparatus.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an image forming apparatus according to the present invention.

[Description of Reference Signs] 1 photoconductor drum 100 (as a drum-shaped image carrier) 100 multicolor developing device (as a rotary developing device) 201 intermediate transfer belt 204 (as a belt-shaped intermediate transfer member) (as a transfer unit) Secondary transfer bias roller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 21/00 118

Claims (3)

[Claims] 1. A drum-shaped image carrier, latent image forming means for carrying an electrostatic latent image corresponding to an image of each color on the drum-shaped image carrier, and a plurality of drum-shaped image carriers rotated by rotation. A drum-shaped image carrier is provided with a rotary developing device that selectively brings one of the developing units close to the drum-shaped latent image carrier to visualize the electrostatic latent image on the drum-shaped image carrier. In an image forming apparatus having one belt-shaped intermediate transfer member that temporarily holds the electrostatic latent image carried on, a drum-shaped image carrier is provided on one side surface of the belt-shaped intermediate transfer member placed in the vertical direction, A rotary developing device is arranged on one side surface of the drum-shaped image carrier, and a transfer means for transferring a toner image onto a transfer paper is provided at the uppermost part of one end of the belt-shaped intermediate transfer member. Image forming apparatus. 2. A bias roller which is controlled so as to be able to come into contact with and separate from the belt-shaped intermediate transfer member is provided as a transfer unit from the belt-shaped intermediate transfer member to the transfer paper, and the bias roller is provided. A color image forming apparatus characterized in that a sheet feeding means, a fixing means, and a conveying means are provided so as to be orthogonal to the transfer section. 3. The transfer paper conveying means is arranged so as to be orthogonal to the transfer means, and the drum-shaped image is provided above the drum-shaped image carrier and the rotary developing device and below the transfer-paper conveying means. A color image forming apparatus characterized in that a laser writing means is provided on a carrier.