JP3007136B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates to an image forming apparatus that performs development almost simultaneously with exposure using a photoconductive toner, and more particularly to a color image forming apparatus that performs multicolor image formation while sequentially performing development with a plurality of types of photoconductive toners.

[0002]

[Prior art]

Conventionally, a photosensitive drum comprising a light-transmitting conductive layer and a photoconductive layer laminated on a light-transmitting support is used, the exposure means is provided on the inner peripheral side of the drum, and the charging and developing steps are performed on the outer peripheral side of the drum. An image forming apparatus which is arranged on the side of the image forming apparatus and performs development at the same time as or immediately after exposure is known (see Japanese Patent Application Laid-Open No. 58-153957).
In this type of apparatus, conductive toner is used in view of facilitating image formation during development. However, if conductive toner is used, there is a problem in a transfer process to a recording material. Easy to come out.

In order to solve such a drawback, a photoconductive toner is used as the toner, and at the time of development, the toner is made conductive by light injection by exposure, thereby facilitating image formation.
At the time of transfer, a technology has been developed which enables transfer while maintaining high resistance (JP-A-1-196076). In general, photosensitive materials such as OPC and zinc oxide are used for the photoconductive toner. However, any of these members is liable to be deteriorated by ultraviolet rays or heat due to the repeated exposure. As for the apparatus using the LED, an apparatus using an LED array capable of exposing at a specific wavelength has been proposed.

[0004]

[Problems to be solved by the invention]

For this type of backside exposure apparatus, colorization is also being studied.For example, in Japanese Patent Application Laid-Open No. 1-102583, an exposure unit for generating an image corresponding to each color is formed by an LED array, and each color is exposed. -A technique that enables multicolor development while repeating development has been proposed, but using three or four LED arrays corresponding to each color in this manner is difficult.
Since the LED array is expensive, not only does the apparatus cost tend to be large, but in the case of LEDs, the wavelengths to be used are limited, so that it is not possible to obtain the most preferable wavelengths for the respective colors.

In order to solve such a drawback, only three or four developing devices are arranged in the circumferential direction, while only one exposing device or the like composed of an LED array and a lens system is positioned at the position of the developing device group in the drum rotation direction. The drum 1 is arranged on the upstream side using the one exposure device or the like.
A technique (Japanese Patent Laid-Open No. 2-198466) has been proposed which enables multi-color development while performing exposure / corresponding color development for each rotation. In such a technique, it is assumed that exposure and development are performed simultaneously. Not only cannot it be applied to a device using a conductive toner, but also the drum must be rotated by the number of corresponding colors (the number of developing units), and the image forming speed is necessarily delayed. You.

In view of the drawbacks of the prior art, the present invention makes it possible to expose the photoconductive toner with light having the most preferable wavelength while reducing the apparatus cost, thereby improving the durability of the toner. It is an object to provide a forming device. It is another object of the present invention to provide an image forming apparatus capable of easily forming a color image without reducing the image speed while reducing the apparatus cost.

[0007]

Means for Solving the Problems In order to achieve the technical object, the present invention uses a white light source instead of using a light source of a specific wavelength like an LED, and outputs the white light before forming a light image or After the formation of a photo image, the photoconductive toner to be developed is transmitted through a wavelength selection filter corresponding to the wavelength most suitable for the photoconductive toner, and the exposure is performed using the selected wavelength light obtained through the filter. It is.

In this case, the filter is configured separately from the exposure unit configured to be sequentially movable to a position facing each of the developing units and the image carrier therebetween, and includes at least the one developing unit and It is fixed and arranged at a position facing the image carrier.

For example, in a color image forming apparatus in which a plurality of developing units accommodating photoconductive toners for each color are arranged along the moving direction of the image carrier, when the optimum wavelength differs for each color toner. For this reason, it is preferable to separately provide each developing unit. On the other hand, in an exposure system main body including a white light source and an image forming shutter, if an individual exposure system is provided for each developing unit, the number of parts increases. This leads to an increase in the size of the device, which is not preferable.

Therefore, in the present invention, an exposing unit including a white light source and an exposing system including an image forming shutter is commonly used, and the developing unit and the developing unit can be moved to positions facing each other with the image carrier interposed therebetween. The selection filter is fixedly disposed at a position facing at least the one developing unit. Note that a liquid crystal shutter is generally used as the image forming shutter, but the invention is not limited to this.

[0011]

【Example】

Hereinafter, embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. Not just. FIG. 1 shows a main configuration of an image forming apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a hollow member formed by laminating a light-transmitting conductive layer 1b and a photoconductive layer 1c on a drum-shaped light-transmitting support 1a. A cylindrical photosensitive drum is configured to be rotatable in the direction of the arrow, and the conductive layer 1b is grounded.

Each developing cartridge 5Y containing photoconductive magnetic toner of each color of yellow, magenta, cyan and black is arranged on the outer peripheral side of the photosensitive drum 1 along the rotation direction.
Are arranged at a predetermined distance in the circumferential direction, and the transfer roller 6 and the cleaning member 7 are arranged on the downstream side in the circumferential direction.
The recording paper transport path 8 is formed along the tangential direction of the transfer roller 6, and a registration roller 9 and a fixing roller 10 are arranged on the transport path 8.

An exposure system 2 is provided in the photosensitive drum 1 so as to be able to swing around an axis of the drum 1 in an angular range corresponding to the area in which the cartridges 5Y are arranged. The wavelength selection filters 4Y are fixedly arranged on the inner peripheral surface side of the photosensitive drum 1 facing the developing position of 5Y.

Next, the configuration of the main part of each of the members will be described. The cartridge 5Y has an opening on the side facing the photosensitive drum 1 of the toner container 51 containing the photoconductive magnetic toner of each color, and a developing sleeve 53 containing a fixed magnet assembly 52 is disposed in the opening. By rotating the sleeve 53 in the direction of the arrow, the toner whose layer thickness is regulated on the container 51 side is guided to the developing position, and the toner 50 is exposed to the toner 50 while rubbing the surface of the photosensitive drum 1 at the developing position. Is irradiated, the resistance value of the portion corresponding to the exposure image 20 is lowered, and electric charge is injected.
Performs a predetermined development. In addition, the toner 50 is a magnetic powder, a charge control agent,
Photosensitizers such as zinc oxide and cyan, magenta, yellow,
It is made of a color forming agent such as black, and is formed by pulverizing and classifying them.

The exposure system 2 includes a white light source 21 and a lens 2
2. The image forming liquid crystal shutter 23 and the focusing lens 24 are arranged along the optical path in the radial direction, and these are integrally fixed to the support 25.

The wavelength selection filters 4Y are formed by coating the optical glass surface in a laminated manner so that only the optimum wavelength of the toner can be transmitted. The filters 4Y... May have different wavelengths according to the respective toners, and may not be used as needed for black toners with little decrease in durability.

Next, the operation of the embodiment will be briefly described. First, while the exposure system 2 is moved to the developing position of each cartridge 5Y, a multicolor toner image is carried while superposing the yellow, cyan, magenta, and black toner images sequentially, and timing is taken by a registration roller. Then, the toner image is transferred onto the recording paper guided to the transfer roller 6, and then the toner image transferred onto the recording paper is fixed by the fixing roller. Therefore, according to this embodiment, since the development is performed simultaneously with the exposure, all the four types of toner can be developed by one rotation of the photosensitive drum 1, which leads to an increase in the recording speed.

[0018]

【The invention's effect】

As described above, according to the present invention, a white light source can be selected to an arbitrary wavelength without using an LED array.
Development can be performed, whereby the photoconductive toner can be prevented from deteriorating and durability can be improved while reducing the apparatus cost. Even if one exposure system is used, a multicolor image can be formed by one rotation of the photosensitive drum, whereby a color image can be easily formed without delaying the image speed. And so on.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a main image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image carrier 2 ... Exposure system 4Y ... Wavelength selection filter 21 ... White light source 23 ... Shutter for image formation

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-213673 (JP, A) JP-A-2-198466 (JP, A) JP-A-1-196076 (JP, A) JP-A-59-1984 121359 (JP, A) JP-A-56-144176 (JP, A) JP-A-63-79465 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/05 G03G 13 / 01 G03G 15/01 G03G 15/04

Claims (1)

(57) [Claims] 1. An exposure system including a white light source and an image forming shutter on one side with an image carrier formed by laminating a light transmitting conductive layer and a photoconductive layer on a light transmitting support. The configured exposure means and, on the other side, a plurality of developing means containing photoconductive toners corresponding to each color are arranged along the moving direction of the image carrier, and image formation is performed while moving the image carrier. In the image forming apparatus, the exposing unit is configured to be sequentially movable to a position facing each of the developing units and the image carrier, and a wavelength selection filter that transmits a light image from the exposing unit is at least one of the wavelength selecting filters. And fixedly arranged at a position facing the developing means and the image carrier, and configured so that a light image from the exposing means can be formed on the photoconductor layer via the wavelength selection filter. An image forming apparatus comprising: