JPH02287384A - Electrophotography device - Google Patents

Abstract

PURPOSE:To prevent toner or foreign matter from being accumulated in the inner part of an image carrier by providing an air pressure raising means inside the image carrier provided with a light transmitting base layer and a photoconductive layer. CONSTITUTION:The image carrier 1 is formed by using a cylindrical glass material 13 as the light transmitting conductive base layer and the air pressure raising means 24 is arranged inside the image carrier 1. The air pressure raising means 24 is provided by arranging a fan motor 21 outside the image carrier 1, connecting it there through a duct 19 so that air pressure inside the image carrier 1 is raised and setting the other end of the duct 19 in the center in the axial direction of the image carrier 1 and also in the central part of the image carrier 1. Thus, pressure difference occurs between the inner part and the outer part of the image carrier 1, whereas the toner and the foreign matter are prevented from entering.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic apparatus that uses an electrophotographic process to obtain multicolor recorded images using laser beams, LEDs, LCDs, etc. , multicolor electrophotography that enables multicolor printing by repeating the exposure and development steps according to image information multiple times to form a multicolor visible image on a latent image carrier and then transferring it onto a recording material. Regarding equipment.

[Prior Art] Currently, printers using electrophotography are computers,
It has been widely used as an output device for facsimile, CAD, etc.

These devices form one image information as a latent image on an electrostatic latent image carrier using a laser LED, LCD, etc., convert it into a visible image using a developing device, and then
A recorded image is obtained by transferring a visible image onto a recording material and fixing it, but in conventional printers, the recorded image is of one color, for example, black. However, recently, for reasons such as recording images becoming clearer and information easier to understand, for example, the color of the format and the color of the calculated value or data value are expressed in different colors, or It is desired to obtain a recorded image by distinguishing it by two or more colors, such as outputting a part of a drawn drawing in a different color.

This enables multicolor recording. Taking a four-color printer as an example of an electrophotographic apparatus, an image forming process using an image forming apparatus as shown in FIG. The process of the apparatus includes, for example, uniformly charging the surface of the image carrier 1 negatively with a scorotron 2 (hereinafter referred to as a charger).

Next, an electrostatic latent image is formed on the image carrier l by irradiation with the laser light 3 modulated according to the first image information.

This first electrostatic latent image is subjected to reversal development by the first developing device 4 (reversal development means that the color toner T1 is attached to the uncharged area of the image carrier l irradiated with the laser beam 3, and the first electrostatic latent image is ).

Then, in the second rotation, the charger 2 uniformly charges the image carrier l, including the toner T1, again. The toner T, on the body L is not disturbed).

Then, an electrostatic latent image is formed on the upper surface of the image carrier 1 by laser light 3 modulated according to second image information different from the first image information, and color toner T2 different from the first image is applied to the electrostatic latent image. A second reversal development is performed using the developing device 5 having the following.

Similarly, in the third and fourth rotations, color toners T, , T, are applied to the image carrier l from the developing device 6.7 for reversal development, so the charger 2 is turned over and the third Image information, 4th
The laser beam 3 is repeatedly modulated so as to form a latent image according to the image information, thereby obtaining a multicolor image on the upper surface of the image carrier l.

Note that although the operation of the developing units has been explained in the order of developing units 4, 5, and 6.7 above, the operations of developing units 4, 5, and 6.7 are explained according to the image information of each.
5, 6.7 can be arbitrarily selected.

The multicolor toner image formed on the image carrier L as described above is transferred onto the recording material P supplied by the transfer charger 9. This recording material P is separated from the image bearing member 1 by a separation static eliminator 10 and conveyed to a fixing device 11, where the toner image is fixed. Further, the residual toner on the image carrier 1 is scraped off by the movement of the rubber blade 8a (solid line position) of the cleaner 8, and the image forming process is repeated again.

[Problem that the invention seeks to solve] However,
The conventional example described above is preferable as a color image forming apparatus, but the drawback is that the toner T is developed on the upper surface of the image carrier L, and when an attempt is made to expose the image forming part, the toner T absorbs the exposure light, so the laser The surface potential cannot be attenuated accurately in response to the light from the light 3, making it difficult for the toner T to adhere. This becomes increasingly difficult as the number of toner T layers increases to two or three layers on the image bearing member 1, resulting in defects in the image or indistinct color tones.

As a means of solving this problem, an attempt was made to solve this problem by providing a photoconductive layer on a light-transmitting conductive substrate and irradiating light from the side of the light-transmitting conductive substrate, as detailed in Japanese Patent Publication No. 61-20960. There are some.

However, this proposed method had the following drawbacks.

(1) Due to the scattering of toner T from the developing device and the wrap-around of foreign matter from the surroundings, during long-term image formation, this is accumulated on the light-transmitting conductive substrate, absorbs the light from the laser 3, and cannot reach the photoconductive layer. Five images are missing, and in the end, no image can be formed at all.

(2) When using an exposure device such as a RAD array for an LCD or a RAD array for an LED, a SELFOC lens array (trade name of Nippon Sheet Glass) is usually inserted between the LED array and the image carrier to connect the LCD or LED head. The image is formed between the image carrier and the image carrier, but it is contaminated by the toner and foreign matter, resulting in an extremely low optical efficiency and an unclear recorded image.

(3) Since the optical system is housed inside the image carrier, cleaning the optical system is difficult for the user and requires the specialized knowledge of an experienced person, resulting in increased costs and problems in handling.

For reasons (1), (2), and (3) above, the above proposed method was not very practical.

[Means for solving the problems] The present invention has been made in view of the above points, and the present invention has the following features:
By providing an air pressure increasing means inside an image carrier having a light-transmitting base layer and a photoconductive layer, it is intended to prevent toner and foreign matter from accumulating inside.

[Example] FIG. 1 is a schematic sectional view of the present invention, and FIG. 3 is a partial sectional view of the image carrier l shown in FIG. In FIG. 3, a cylindrical glass material 13 is used as a light-transmitting conductive base layer, conductive ITO (indium thene oxide) 14 is deposited on the outer peripheral surface, and zinc oxide, amorphous silicon, organic selenium, etc. In this embodiment, an organic semiconductor was used as the image carrier 1, which was coated or vapor-deposited with a photoconductive layer 15.

The image carrier 1 is mounted on the apparatus shown in FIG. 1, rotated in the direction of the arrow, and a high voltage corona discharge is generated in the charger 2 by the high voltage power source 20, and the potential on the surface of the image carrier 1 reaches -600 (V). do.

Next, the image processing circuit 17 supplies the first image information to the LED head array 16, and the image information light from the LED head array 16 is focused on the photoconductive layer 15 by the SELFOC lens array 18, and the image carrier Form an electrostatic latent image on the top surface. This electrostatic latent image is visualized by adhering toner T through reversal development in the same manner as described in FIG.

In the next second rotation, the charger 2 charges the upper surface of the image carrier l approximately -
650 (V) from the high voltage power supply 20, and the image processing circuit 17 supplies the second image information to the LED head array 1.
6, and the image information light 3 from the LED head array 16 is passed through the SELFOC lens array 18 to the image carrier l.
An image is formed on the upper surface, an electrostatic latent image is created, and the toner T2 is attached.

Similarly, in the third rotation, the voltage on the image carrier l is set to approximately -700 (V) and the third image is formed using toner T3, and in the fourth rotation, the voltage on the image carrier l is set to approximately -750 (V). The fourth image is formed using toner T4.

The multicolor toner images formed in the above process are transferred all at once to the recording material P and fixed, as described in FIG.

However, as described above, when image exposure is carried out from the back side of the image carrier 1, problems arise due to contamination by toner T and foreign matter inside the machine.

As a means of solving this problem, an air pressure increasing means 24 as shown in FIG.
By arranging the inside of the image carrier 1, the image carrier l
This is to prevent the back side of the paper from getting dirty.

In the present invention, as the air pressure increasing means 24, a fan motor 21 is disposed outside the image carrier 1, and is connected to the fan motor 21 by a duct 19 in order to increase the air pressure inside the image carrier 1.
The inventor has found that by providing the other end at the axial center of the image carrier and at the center, a pressure difference is created between the inside and outside of the image carrier l, thereby preventing the ingress of toner and foreign matter. It became possible to do so.

Specific examples will be described below.

In the device shown in Fig. 1, the image carrier l has a diameter of 140 am and a wall thickness of 2
-1, Width 260■I, Sanyo Electric ■model name 109PO824H602 is operated as the fan motor 21 at the rated value, and when used as a duct with a diameter of 4ollI, the inner surface of the image carrier l will not be contaminated for a long period of time. Moreover, a heating element 1 within the image carrier 1, for example a laser diode.

It has been confirmed that it is also effective in cooling light sources such as light emitting elements such as LEDs and liquid crystal shutter arrays.

[Other Embodiments] Further, by arranging an air filter 25 near the fan motor 24 in a part of the device shown in FIG. 1 as shown in FIG. 4, it is possible to obtain effects greater than those shown in FIG. 1. It became.

FIG. 5 shows a polyester film 7 as a transparent conductive film 13' in place of the glass cylinder of the image carrier explained in FIG.
A conductive layer 14 of ITO was vapor-deposited on the top surface of 5 gm, and a photoconductive layer 15 was coated thereon to a thickness of 25 gm. (
(See FIG. 6) The image carrier belt l is rotated in the direction of the arrow by the drive roller 22, and images are formed in the same manner as described in FIG. 1. At this time, as in the explanation in FIG.
By increasing the air pressure inside the image carrier l, not only is image formation uniform over a long period of time, but also foreign matter does not get mixed in between the image carrier l and the driving roller 22 or the driven roller 23, and the image carrier l It is possible to prevent slippage between the drive roller and the drive roller, and it is also possible to keep the circumferential speed of the image carrier constant.

All of the configurations described above have been explained using four colors (four developing devices), but similar effects can be obtained with a developing device configuration of two or more colors.

Similarly, a plurality of charging devices and developing devices are arranged on the outer surface of the image carrier, and the same number of image exposure devices as charging and developing devices are arranged on the inner surface of the image carrier, and image formation is performed by repeating charging, exposure, and development on the image carrier. A similar effect can be achieved by a method in which images are continuously transferred onto a transfer material while the image is being moved.

[Effects of the Invention] As explained above, in an apparatus that performs exposure from the back side of an image carrier to form an image, by providing a pressure increasing means inside the image carrier, 1. Stability over a long period of time can be achieved. 2. Because the circumferential speed is constant, there is no distortion of the image or poor registration. 3. The image does not become unclear.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing a conventional example, FIGS. 3 and 6 are sectional views showing the structure of an image carrier, and FIGS. 4 and 5. FIG. 3 is a sectional view showing another embodiment of the present invention. In the figure, l is an image carrier, 13 is a light-transmitting base layer, and 15
24 is a photoconductive layer, and 24 is an air pressure increasing means.

Claims (1)

[Claims] (1) In an electrophotographic device that repeats image formation multiple times on an image carrier having a photoconductive layer provided on a light-transmitting base layer to form a visible image of multiple colors, and then transfers this to a recording material, the image carrier is An electronic device characterized by having at least one light irradiation means provided inside the body and irradiating light information according to image information from the light-transmissive base layer side, and an air pressure increasing means provided inside the image carrier. Photographic equipment.