JPH02219079A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To prevent accumulation of toner and a foreign matter and to obtain a stable image for a long time by providing at least one light irradiation means for writing an image on the basic side of the light transmitting conductive layer of an image carrier and disposing a cleaning means which removes the foreign matter or toner. CONSTITUTION:A first information is supplied to an LED head array 16 by an image processing circuit 17, and an image pattern light is image-formed on a photosensitive layer 15 by a selfoc lens array 17 in order to form an electrostatic latent image on the surface of the image carrier 1. In a second rotation, an electrifier 2 supplies power from a high voltage power source 20 in order to set the potential of the surface of the image carrier 1 at the prescribed value. A second information is supplied to the LED head array 16 by the image processing circuit 17. Then, the image light 3 is combined on the surface of the image carrier 1 through the selfoc lens array 18, and the electrostatic latent image is formed to adhere toner T2. In this way, when an image is exposed at the back of the image carrier 1, the back face is always cleaned by providing the cleaning means 19. Additionally, the stable image can be obtained for a long time.

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 a multicolored recorded image using a laser beam, an LED, an LCD, etc. A multicolor electrophotographic device that can perform 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.

[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 output using CAD. It is desired to obtain a recorded image by distinguishing it by two or more colors, such as outputting a part of a printed drawing in another color.

Taking a four-color printer as an example of an electrophotographic device that enables such multicolor recording, for example, an image process using an image forming device as shown in FIG. 60-76766). In the process of this image forming apparatus, for example, a load is uniformly charged by a scorotron charger 2 (hereinafter referred to as a charger) on the surface of an ft carrier 1.

Next, a static latent image is formed on the image carrier l by the laser beam 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 is a process in which color toner T is attached to an uncharged area of the image carrier L that has been irradiated with a laser beam 3.
toner image).

Then, in the second rotation, the charger 2 uniformly charges the image carrier l, including the toner T (also, since the cleaning section 8a of the cleaning device 8 is released to the position indicated by the broken line 8a', the image carrier l The upper toner T1 is not disturbed)
.

Then, an electrostatic latent image is formed on the upper surface of the image carrier l by a laser beam 3 modulated with second image information different from the first image information, and a color toner T2 different from the first image is developed on this latent image. A second development is performed using the container 5.

Thereafter, in the same manner, the charger 2 is repeatedly operated to develop the color toner T:l, T4 from the developer 6.7 on the image carrier l in the third and fourth rotations, and the third image and the fourth image are generated. Repeat this to modulate the laser beam 3 so that it forms. As a result, a color image is obtained 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 photoreceptor drum 1 as described above is transferred onto the recording material P supplied by the transfer charger 9. This recording material P is separated from the photoreceptor drum 1 by a separation static eliminator 1O and conveyed to a fixing device 11, where the toner image is fixed. Further, the residual toner on the photosensitive drum 1 is scraped off by the movement of the rubber blade 8a (solid line) of the cleaner 8, and the same image forming process is repeated again.

[Problems to be Solved by the Invention] However, although the above-mentioned conventional example is preferable as a color image forming apparatus, the disadvantage is that the toner T is developed on the upper surface of the image carrier l.
When an attempt is made to expose the image forming part, the toner T absorbs the exposure light, so the surface potential cannot be attenuated in response to the image light from the laser beam 3 accurately, and the toner T adheres. It becomes difficult. This becomes increasingly difficult as the number of toner T layers increases to one layer of the image bearing member, and as a result, the image may be missing or one color tone may be unclear.

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 is.

However, this proposed method had the following drawbacks.

(1) Due to scattering of the toner T from the developing units 4, 5, 6.7 and the intrusion of foreign matter from the surroundings, the toner T is accumulated on the light-transmitting conductive substrate during long-term image formation and absorbs the light from the laser 3. The photoconductive layer cannot be reached, resulting in missing images,
In the end, no image can be formed at all.

(2) When using an exposure device such as a liquid crystal shutter array or an LED head array, a SELFOC lens array (trade name of Nippon Sheet Glass) is usually inserted between the LED array and the image carrier 1.
An image is formed between the D head and the image carrier 1, and normally the distance between the SELFOC lens array and the image carrier 1 is kept constant using pressing rollers, etc. Due to changes in distance due to toner and foreign matter accumulated on the camera, fish collection was not completed and one image became unclear.

(3) Since it cannot be used for a long period of time, it is not practical for the user to replace or clean the image carrier l, which increases the cost and makes it difficult to handle.

[Means for Solving the Problems] According to the present invention, at least one image writing light irradiation means is provided on the light-transmitting conductive substrate side of the image bearing member, and a cleaning means for removing foreign matter and toner is further provided. This arrangement attempts to prevent the accumulation of toner and foreign matter.

[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 substrate 12, and conductive ITO (indium thene oxide) 14 is vapor-deposited on the outer peripheral surface, and zinc oxide and amorphous silicon are further deposited.

In this embodiment, an organic semiconductor was used as the image carrier 1, which was coated or vapor-deposited with a photoconductor layer 15 of organic selenium or the like.

This 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 supply 20, and the potential on the surface of the image carrier 1 is brought to -600 (V). do.

Next, the image processing circuit 17 supplies the first image information to the LED head array 16, and the image pattern light from the LED head array 16 is imaged on the photosensitive layer 15 by the SELFOC lens array 18, and the upper surface of the image carrier l is An electrostatic latent image is formed. This electrostatic latent image is developed by reversal development as described in FIG.

A toner is applied to form a visible image.

In the next second rotation, the charger 2 charges the upper surface of the image carrier l by 1@
-650 (V) is supplied from the high-voltage power supply 20, and the image processing circuit 17 supplies the second image information to the LED head array 16, and the image light 3 from the LED head array 16
is coupled to the upper surface of the image carrier l through the SELFOC lens array 18 to create an electrostatic latent image and adhere T2 toner.

Similarly, in the third rotation, the image carrier L is charged to approximately -700 V and the third image is formed using toner T3. In the fourth rotation, the image carrier L is charged to approximately -750 (V), and the 4 image formation T
Use 4 toners.

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

However, as described above, when image exposure is performed from the back side of the image carrier l, it is contaminated by toner T and foreign matter inside the machine, causing problems.

As a solution to this problem, the back surface was constantly cleaned by providing a cleaning means 19 as shown in FIG. 1, and stable images were obtained over seven periods.

In the present invention, the polyurethane plate rubber 21 as the cleaning means 19 is arranged in the opposite direction to the direction of movement of the image carrier l, but it may be arranged in the forward direction.

Further, the same effect can be obtained by pressing a felt material or the like in place of the plate rubber 21 or by replacing it with a rotating bristle brush or the like.

Although not shown in the drawings, the cleaning means 19 may be provided with a rotating screw or the like for collecting toner, foreign matter, etc., and may be collected by installing a waste box or the like on one side.

FIG. 4 shows the image carrier 1 viewed from the SELFOC lens 18. The SELFOC lens 18 is supported by a rotating roller 22 in order to always maintain a constant distance from the image carrier L, and the rotating roller 22 is connected to the image carrier. l It is touched on the back side. As shown in Fig. 4, by making the width of the rubber blade 21 of the cleaning device $119 sufficiently wider than the rotating roller 22, the rotating roller 22 can also be kept stable for a long period of time without being contaminated. It became.

When an image was produced using the above apparatus using cyan toner as T1, magenta toner as T2, yellow toner as T3, and black toner as T4, a uniform color image could be obtained over a long period of time.

[Other Examples] FIG. 5 shows a polyester film 7 as a transparent conductive film 13' in place of the glass cylinder of the image carrier described in FIG.
A conductive layer 14 of ITO was deposited on the top surface of the 5ILm, and a photosensitive layer 15 was coated thereon to a thickness of 25mm. (See FIG. 6) The drive roller 22 drives the image carrier belt l.
is rotated in the direction of the arrow and images are formed in the same manner as explained in FIG.
9, not only does image formation become uniform, but also there is no foreign matter mixed in between the image carrier l and the drive roller 22 or the driven roller 23, and there is no slippage between the image carrier l and the drive roller. It has become possible to prevent this from occurring and also to maintain a constant peripheral speed of the image carrier.

FIG. 7 shows the same recording process as FIG. 5.

Uniform charging is applied to the image carrier l by the charger 2, and a first image signal is provided to the LED l 6 to form an electrostatic latent image on the image carrier l, which is then visualized with toner T, and further Uniformly charged by the second charger 2', the second image signal is sent to the LED
16' to form an electrostatic latent image of the second image on the image carrier l, and then toner T2 is applied from the developing device 5, and the third image signal and the fourth image signal are sent to LEDlB"LEDlB" in the same manner as described above.
A similar effect can be obtained by forming a recorded image on the image bearing member L by applying it to "'", and then transferring and fixing it to the recording paper P.

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

Moreover, an LCD, a laser optical system, etc. may be used instead of the LED.

[Effects of the Invention] As explained above, by performing backside exposure of the image carrier and providing a cleaning device on a part of the image exposure side of the image forming apparatus, 1. Stable images can be provided over a long period of time. 2. Since the circumferential speed is constant, there is no distortion of the image or poor registration. 3. The fish collection in the image is constant, so the image does not become unclear.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is a schematic diagram showing a conventional example, Fig. 3 is a partial cross-sectional view of the image carrier shown in Fig. 1, and Fig. 4 is an image of the image carrier shown in Fig. 1. An explanatory diagram illustrating the axial direction of the carrier,
FIG. 6 is a partial sectional view showing another example of the image carrier, and FIGS. 5 and 7 are schematic views showing other embodiments. 1 is an image carrier 13, 13' is a transparent substrate 14 of the image carrier, a conductive layer 15 is a photoconductive layer 19, and a cleaning means. Figure 1! Male 6f1 == Cry

Claims (1)

[Claims] (1) Image formation is repeated multiple times on an image carrier having a photoconductive layer on a base layer that is transparent to image signal light to form a visible image in multiple colors, and this is transferred to a recording material. An electrophotographic apparatus comprising: at least one light irradiation means for exposing an image from the light-transmissive base layer side of the image carrier; and a cleaning means for cleaning the light-transparent base layer side of the image carrier. .