JPH0524251A - Image forming device - Google Patents

Abstract

PURPOSE:To make a carriage and a drive motor small in size by a method wherein a photosensitive drum incorporating an exposing means is provided on the carriage together with a developing means, and the carriage is so constructed as to integrally move orthogonally to a recording medium travel direction. CONSTITUTION:A photosensitive drum 10 incorporating an exposing means 14 is provided on a carriage 5 together with a developing means 15. The carriage 5 is so constructed as to integrally move orthogonally to the travel direction of a recording medium 9. In this manner, a carriage assembly and a drive motor therefor are respectively made small in size. A toner image held on the photosensitive drum 10 can be transferred to the recording medium 9 through an intermediate transfer body 3, which is made of a high-resistance or insulating material and can move in a predetermined direction. The photosensitive drum 10 is so constructed as to move orthogonally to the travel direction of the intermediate transfer body 3. In this manner, when a conductive toner is used, the deterioration of a printing quality is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which an exposing means is incorporated in a photoconductor, and particularly to provide an image forming apparatus suitable for a serial printer.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic printer, a photosensitive drum is extended along a recording paper width direction for transferring a toner image, and a process of exposing, developing, transferring, discharging and other processes is performed around the drum. By adopting a line printer method in which electrophotographic printing is performed while arranging means, the peripheral speed of the photosensitive drum and the moving speed of the recording paper are made to coincide with each other, the same as in the conventional thermal type or inkjet method Also in the system, the movement for serialization is being considered. For example, in Japanese Patent Publication No. 60-23033,
The photosensitive drum is formed as a thin-walled cylindrical body, and the photosensitive drum and the process means arranged around the photosensitive drum are mounted on a carriage that can reciprocate in the platen axis direction, and the carriage is reciprocally moved on the platen. An apparatus has been proposed that prints and records on plain paper that has entered.

[0003]

However, it is necessary to mount on the carriage all the process means such as exposure, development, cleaning, charge removal, and charging, which are arranged around the photosensitive drum, together with the size of the carriage, as well as the photosensitive drum. A drive motor for driving the process means has to be mounted together, and as a result, the drive system for reciprocating the carriage has to be increased in size due to an increase in the weight of the carriage. Therefore, the merit of downsizing due to serialization is not utilized, and in recent years, personal computers and word processors are becoming smaller, which is not preferable as a printer corresponding to this.

In view of the above-mentioned drawbacks of the prior art, the present invention comprises a serial type electrophotographic apparatus, but downsizes a carriage on which a photosensitive drum or the like is mounted and a drive system for reciprocating the carriage. By this,
An object of the present invention is to provide an image forming apparatus which can easily be downsized in correspondence with recent personal computers and word processors.

[0005]

The process leading to the present invention will be described step by step. In recent years, an exposure head that generates a light output corresponding to image information is inserted into a photosensitive drum formed by laminating a transparent conductive layer and a photoconductive layer on a transparent support, At the same time as or immediately after the light output is focused to form a latent image on the photoconductor layer, the latent image is made a visible image (toner image) through a developing unit facing the photosensitive drum. After that, an image forming apparatus is disclosed in which the toner image can be transferred onto plain paper through a transfer roller or other intermediate transfer body. (JP-A-58-153957, etc.)

In this type of image forming apparatus, the exposure head and the charge removing means attached to the exposure head are inserted in the photosensitive drum, and the conductive toner is not provided with an independent charger. In order to inject charge and clean by the toner reservoir provided on the upstream side of the developing position using, the number of process means placed around the photosensitive drum except the developing device is significantly less than that of the conventional Carlson method. Has the effect of becoming. Therefore, it is possible to form a serial type image forming apparatus by narrowing the width of both the photoconductor drum and the developing device and mounting them on a carriage that can reciprocate in a direction orthogonal to the recording paper moving direction. Yes,
As a result, the above-mentioned drawbacks of the Carlson-type serial electrophotographic apparatus can be solved all at once, and since the photoconductor drum itself is flattened, the exposure head and the photoconductor drum itself occupy a large weight in terms of cost. Manufacturing cost is greatly reduced, and its practical value is great.

In the invention described in claim 1, paying attention to such a point, a photosensitive drum including an exposing means is provided together with a developing means.
It is characterized in that it is mounted on a carriage and the carriage can be integrally moved in a direction orthogonal to the recording medium moving direction.

However, in the image forming apparatus, the conductive toner is used as the toner in order to have the structure in which the charged electric charge is injected from the developing sleeve to the drum side by the toner accumulation on the upstream side of the developing position as described above. Generally, when such a conductive toner is used, the toner carrying force on the recording material side after the transfer fluctuates due to the variation in the volume resistance value on the recording paper side to be transferred. If the serial method is used in the forming device, it takes time to fix the image after it is transferred to the recording medium, and the unfixed toner image transferred to the recording medium is disturbed due to vibrations during movement of the recording medium, resulting in stable printing. I can't get the quality.

Therefore, according to the second aspect of the invention, the toner image is not directly transferred to the recording medium, but is transferred to an intermediate transfer member formed of a high resistance or insulating material, and the recording medium side is transferred through the intermediate transfer member. The transfer of the toner image is attempted. That is, according to the second aspect of the present invention, the photosensitive drum having the exposing means built therein is configured to be movable in a direction orthogonal to the moving direction of the intermediate transfer body for transferring the toner image carried on the drum onto the recording medium. In addition, the intermediate transfer member is formed of a high resistance or insulating material.

According to the present invention, similarly to the first aspect of the invention, the developing means is mounted on a carriage together with the photosensitive drum, and the carriage is movable in a direction orthogonal to the moving direction of the intermediate transfer member. However, the present invention is not limited to this. Further, it is generally preferable that the intermediate transfer member is composed of an endless belt, but the present invention is not limited to this, and after the toner image is once carried on the insulating intermediate platen using the insulating intermediate platen. It is also possible to transfer to the recording medium side via the intermediate platen.

[0011]

According to the first aspect of the present invention, the process means mounted on the reciprocating carriage is only the photosensitive drum having the exposure head and the developing device. As a result, the carriage can be downsized, the weight of the carriage can be reduced, and the drive system for reciprocating the carriage can be downsized, which makes it compatible with recent PCs and word processors. Therefore, miniaturization can be easily achieved. Further, by adopting the serial method, the manufacturing cost of the exposure head and the photosensitive drum itself, which occupy a large weight in terms of cost, is significantly reduced, and its practical value is great.

According to the invention of claim 2, claim 1
In addition to the effects described above, it is possible to transfer the unfixed toner image to the recording medium through a high-resistance or insulating intermediate transfer member without directly transferring the unfixed toner image to the recording medium. Deterioration can be completely prevented.

More specifically, since the present invention employs the serial method from the exposure and development on the photosensitive drum to the transfer to the intermediate transfer member, the effect of claim 1 can be smoothly achieved. On the other hand, since the transfer from the intermediate transfer member to the recording medium and the fixing process are performed by the line printing method, the transfer and the fixing of the unfixed toner image to the recording medium can be performed quickly and stably. As a result, the possibility that the unfixed toner image after transfer is disturbed on the intermediate transfer body is reduced. Since the present invention uses an insulating or high-resistance material for the intermediate transfer member, stable toner transfer and conveyance can be performed without changing the toner carrying force during and after serial transfer from the photosensitive drum. The above effect is further promoted, and the print quality is not deteriorated.

[0014]

Embodiments of the present invention will now be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely examples, unless otherwise specified. Not too much. Figure 1
1 shows a serial-type image forming apparatus according to an embodiment of the present invention, which is an insulating intermediate transfer belt 3 which is wound between a pair of rollers 1 and 2 and can be rotated in the direction of the arrow, and on which the belt 3 is provided. Guide rails 4A and 4B extending in parallel in the vertical direction along the direction orthogonal to the circumferential direction, in other words, the roller 1 and 2 axis directions, and a drive system (not shown) axially supported by the pair of guide rails 4A and 4B. The guide rails 4A, 4B
A process means including a carriage 5 having a vertical mounting surface configured to be reciprocally movable along, and a photosensitive drum 10 supported on the vertical mounting surface of the carriage 5 so that the drum axis coincides with the belt winding direction, The transfer charger 6 extending along the drum moving direction so as to be able to face the photosensitive drum 10 via the intermediate transfer belt 3 and the roller 1 of the belt mounting roller are brought into pressure contact with each other, and the roller 1
And a fixing roller 7 that rotates in cooperation with the fixing roller 7.

Next, the structure of each member will be described in detail.
The intermediate transfer belt 3 is formed by coating the surface of the base layer of conductive polyimide with a high resistance or insulating (10 ¹⁰ Ω · cm) fluororesin layer, and the thickness of the fluororesin layer is set to In order to increase the size, the thickness is set as thin as possible, specifically 30 to 10 μm or less. The intermediate transfer belt 3 is configured so as to be revolving in synchronism with one reciprocating operation of the carriage 5 while being stepwise fed by the printing width of the photosensitive drum 10.

As shown in FIG. 3, a drum driving roller 11 and a pair of driven rollers 12 and 13 are rotatably supported on the mounting surface of the carriage 5 so as to be circumscribed on the outer peripheral surface of the photosensitive drum 10. The photosensitive drum 10 is rotatably supported by circumscribing the three support rollers 11 to 13 on the outer peripheral surface of the photosensitive drum 10, and the SELFOC lens 14A and the LED head 14B are integrated in the drum. The exposure device 14 supported by the exposure device 14 is arranged, and the image formation position of the optical image from the exposure device 14 is located on the focal line connecting the photoconductor drum 10 and the axis of the developing sleeve 3 described later.
0 is formed on the photoconductor layer 10c.
In addition, 1a of the enlarged portion of FIG. 3 is a transparent support, and 1b is a transparent conductive layer.

The developing sleeve 15 contains a fixed magnet assembly (not shown), and the toner in the toner container 16 corresponds to the image forming position of the exposing device 14 by rotating the sleeve 15 in the direction of the arrow. It is configured to be guided to the developing position. As shown in FIG. 2, driving motors 17 and 18 for driving the developing sleeve 15 and the drum driving roller 11 are arranged on the surface of the carriage 5 opposite to the drum mounting surface. And the mode
The photosensitive drum 10 by adjusting the rotational speeds of the motors 17 and 18.
And the developing sleeve 15 are configured to be rotatable in opposite directions at a rotational speed such that a relative speed difference occurs.

A bias voltage is applied to the developing sleeve 15, and the developing sleeve 15 and the photosensitive drum 1
The bias voltage applied to the sleeve 15 through the toner reservoir formed on the upstream side of the developing position of the photosensitive drum 10 while rubbing the surface of the photosensitive drum 10 due to the relative speed difference between zero is applied to the photosensitive drum 10 side. It is configured to be injected and uniformly charged. The position of the support roller composed of the drum driving roller 11 and the pair of driven rollers 12 and 13 can be brought into contact with an arbitrary position on the drum peripheral surface which is out of the transfer position from the developing position to the intermediate transfer belt 3. It is arranged.

On the other hand, the fixing roller 7 is the intermediate transfer belt 3
Of the recording paper 9 between the rollers 1 and 7 is pressed against the hanging roller 1 located on the downstream side in the circumferential direction with respect to the position facing the photoconductor drum 10 via the intermediate transfer belt 3 so as to rotate in cooperation therewith. Is inserted so that the unfixed toner image carried on the intermediate transfer belt 3 can be simultaneously transferred and fixed to the recording paper 9 side. The transfer charger 6 is configured to be able to apply a charge having a polarity opposite to that of the conductive toner.

According to such an embodiment, the carriage 5
After the unfixed toner image having a predetermined width is carried on the intermediate transfer belt 3 by rotating the photosensitive drum 10 while moving the intermediate transfer belt 3 forward, Stepwise feeding is performed corresponding to the above, and the unfixed toner image having a predetermined print width is repeatedly transferred onto the intermediate transfer belt 3 by repeating this step. Then, when the unfixed toner image carried on the intermediate transfer belt 3 reaches the pressure contact position of the fixing roller 7, transfer and fixing is carried out on the previously inserted recording paper, and the above operation is repeated. Minute image formation is performed.
Further, according to the above-mentioned embodiment, the color change and the maintenance can be facilitated by replacing the carriage 5.

[0021]

As described above, according to the present invention, since image formation is performed while serially performing from exposure to intermediate transfer, the apparatus configuration is greatly reduced and the photosensitive drum and the exposure head are flattened. It is possible to reduce the number of parts, and also to change colors and facilitate maintenance. It has various remarkable effects.

[Brief description of drawings]

FIG. 1 is a perspective view showing a serial type image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a front sectional view of FIG.

[Explanation of symbols]

3 Intermediate intermediate transfer body 5 carriage 10 Photosensitive drum 14 Exposure means 15, 16 developing means

Claims (4)

[Claims] 1. An image forming apparatus, comprising: a photosensitive drum including an exposing unit and a developing unit, which is mounted on a carriage, and the carriage is integrally movable in a direction orthogonal to a recording medium moving direction. apparatus. 2. A toner image carried on a photoconductor drum containing an exposing means can be transferred onto a recording medium through an intermediate transfer member made of a high resistance or insulating material formed so as to be movable in a predetermined direction. An image forming apparatus characterized in that the photosensitive drum is configured to be movable in a direction orthogonal to the moving direction of the intermediate transfer member. 3. The image forming apparatus according to claim 1, wherein a developing unit is mounted on a carriage together with the photosensitive drum, and the carriage is movable in a direction orthogonal to the moving direction of the intermediate transfer member. 4. The image forming apparatus according to claim 1, wherein the intermediate transfer member is composed of an endless belt or a roller member.