JP2893138B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly, to a method in which a light source for image exposure and a developing device are opposed to each other via a transparent photosensitive member. The present invention relates to an image forming apparatus that forms a plurality of color images on a photosensitive drum while arranging and exposing with an image pattern.

[Prior art and its problems] An image forming apparatus for forming a color image by inserting an exposure device into a photosensitive drum having a transparent electrode layer and a photoconductor layer laminated on a transparent substrate has already been proposed. I have.

In such an apparatus, a plurality of developing devices (four in the case of a full-color system) are arranged around a photosensitive drum, and a toner image is formed by a first developing device during the first rotation of the photosensitive drum, and then transferred. The toner image is formed by the second developing device at the second rotation of the photosensitive drum, and the toner image is formed sequentially thereafter.

In such an apparatus, it is necessary to provide a plurality of exposure devices in the photosensitive drum for a plurality of developing devices, and therefore, the photosensitive drum itself is required to have a large diameter. Therefore, the size of the entire apparatus is increased.
In addition, mounting a plurality of exposure devices increases costs and also makes it difficult to mount the exposure devices.

An object of the present invention is to solve such a problem and realize a compact multicolor image forming apparatus.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a rotatable photoreceptor drum formed by laminating a transparent electrode layer and a photoconductor layer on a transparent substrate; Exposure means for irradiating light selected from image information from the inside of the drum, development means provided to face the exposure means via the photosensitive drum, and developing simultaneously with charging, and developed by the development means In an image forming apparatus provided with a transfer unit for transferring a toner image, a plurality of the developing units are arranged on an outer periphery of the photosensitive drum, and the exposing unit is selectively rotated to a plurality of developing positions by the plurality of developing units. By doing so, a multicolor image can be formed.

[Operation] With the configuration described above, the exposure unit inside the photoconductor drum rotates so as to face the developing device disposed on the outer periphery of the rotating photoconductor drum, and performs exposure and development a plurality of times. A plurality of toner images can be formed.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 are drawings for explaining a first embodiment of the present invention. FIG. 1 is a schematic explanatory view of a main part of an image forming apparatus of the present invention, and FIG. FIG. 4 is an explanatory view showing a drum partial structure.

In the figure, reference numeral 1 denotes a transparent photosensitive drum formed by laminating a light-transmitting conductive layer and a photoconductive layer on a light-transmitting support. An exposure apparatus 2 that can be rotated and positioned is attached. The exposure device 2 includes an LED array for generating a light output corresponding to image information and a converging lens.

In FIG. 1, in a first step of the photosensitive drum 1,
The exposure device 2 is in the rotation position of A, and is charged and developed simultaneously with exposure by the first developing device 3a.
A toner image corresponding to the selectively irradiated light is formed thereon, and the toner image is transferred by a transfer unit 4 as a transfer unit onto the recording paper conveyed by a belt 5 also serving as a conveyance unit. In the second step, the exposure device 2 is rotated and positioned at the position B, and is charged and developed at the same time as the exposure by the second developing unit 3b and transferred by the transfer unit 4 as in the first step. Thereafter, similarly, the exposure device 2 is rotationally positioned at the positions C and D, and the third and fourth processes are performed by the third developing device 3c and the fourth developing device 3d to form a full-color image.

Reference numeral 6 denotes a heat fixing device for fixing the transferred toner image.

 The rotation mechanism of the exposure apparatus 2 will be described with reference to FIG.

The transparent photosensitive drum 1 is formed by transmitting a driving force of a drum rotation motor 7 fixed to the apparatus main body to a drum flange gear 9 via a gear 8. On the other hand, the exposure device 2 inserted into the photoconductor drum 1 has a rotation support shaft 10 facing the inner surface of the photoconductor drum 1 and bearings 11 interposed at both ends of the rotation support shaft 10. It is held coaxially rotatable at a predetermined distance, and one end of the rotation support shaft 10 is coupled to a positioning device 12 by a coupling means 13. The positioning device 12 is for selectively rotating and positioning the exposure device 2 to respective predetermined positions of a plurality of developing devices by a motor or a cam mechanism (not shown).

FIG. 3 is a schematic explanatory view of a main part for explaining a second embodiment of the present invention.

In this embodiment, the developing devices 3a to 3a are provided on both sides of the transparent photosensitive drum 1.
This is an example in which 3d is divided into two and arranged in total of four. The arrangement of the developing units in such a manner has an advantage that the drum 1 can be made smaller and the entire apparatus can be downsized.

In the above embodiment, an example in which a transfer unit is used as a transfer unit has been described. However, in the present invention, a transfer roller may perform transfer that also serves to convey a recording sheet.

As described above, according to the above embodiment, a single exposure device provided in a drum is rotated and used, so that it is possible to cope with a plurality of developing devices and to form a plurality of toner images. It becomes possible.

[Effects of the Invention] According to the present invention, according to the image forming apparatus, simultaneous exposure can be performed for a plurality of developing units using only a single exposure device.
In addition, since only one exposure device is required, a color image forming apparatus that is inexpensive, small, and easy to assemble can be realized.

[Brief description of the drawings]

FIGS. 1 and 2 are drawings for explaining a first embodiment of the present invention. FIG. 1 is a schematic explanatory view of a main part of an image forming apparatus of the present invention, and FIG. FIG. 4 is an explanatory view showing a drum partial structure. FIG. 3 is a schematic explanatory view of a main part for explaining a second embodiment of the present invention. 2. Exposure equipment 3a-3d ... Developer

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 15/04-15/056

Claims (1)

(57) [Claims] A rotatable photosensitive drum formed by laminating a transparent electrode layer and a photoconductor layer on a transparent substrate; an exposure means for irradiating light selected from image information from the inside of the photosensitive drum; An image forming apparatus provided with a developing unit provided to face the exposing unit via the photosensitive drum and developing simultaneously with charging, and a transfer unit for transferring a toner image developed by the developing unit; A multi-color image is formed by disposing a plurality of on the outer periphery of the photosensitive drum and selectively rotating the exposure unit to a plurality of developing positions by the plurality of developing units. Forming equipment.