JP2644585B2 - Electrophotographic equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus for obtaining a multi-color recorded image by using an electrophotographic process and using a laser beam, an LED, an LCD, and the like. A multicolor electrophotograph capable of forming a multicolored visible image on a latent image carrier by repeating each step of exposure and development according to image information a plurality of times, and then transferring it onto a recording material to perform multicolor printing. Related to the device.

[Prior Art] At present, printers using an electrophotographic system have been widely used as output devices for computers, facsimile machines, CADs and the like.

These apparatuses form image information as a latent image on an electrostatic latent image carrier using a laser, an LED, an LCD, or the like, convert the image into a visible image using a developing device, and then transfer the visible image onto a recording material. Although a recorded image is obtained by the defining process, in the conventional printer, the recorded image is, for example, one color of only black. However, recently, for example, because the recorded image is clearer and the information is easier to understand, for example, the color of the format and the color of the calculated value or the data value are expressed in different colors, or output by CAD. It is desired to obtain a recorded image by distinguishing two or more colors, for example, a part of the drawn drawing is output in another color.

As an example of an electrophotographic apparatus capable of performing such multicolor recording, a four-color printer will be described as an example. For example, an image process by an image forming apparatus as shown in FIG. No. 60-76766). In the process of the image forming apparatus, for example, the surface of the image carrier 1 is uniformly charged, for example, negatively by a scorotron (hereinafter referred to as a charger).

Next, the laser light 3 modulated according to the first image information
Irradiation, an electrostatic latent image is formed on the image carrier 1. The first electrostatic latent image is first deposited color toner T ₁ at no charge on the image bearing member 1 which is irradiated by the laser beam 3 to the reverse development is the (reversal development by the first developing unit 4 Forming one toner image.)

Then again uniformly charged, including the toner T ₁ of the on the image bearing member 1 by the charger 2 to the second rotation (Note that Tamezo carrier cleaning section 8a of the cleaning device 8, which is released at the position of the broken line 8a ' body toner T ₁ of the on 1 will not be disturbed).

An electrostatic latent image is formed on the upper surface of the image carrier 1 by the laser light 3 modulated according to the second image information different from the first image information. _{The second} reversal development is performed by the developing device 5 having ₂ .

Similarly, at the third and fourth rotations, the color toners T ₃ and T ₄ are applied to the image carrier 1 by the developing devices 6 and 7 to perform the reversal development. The laser beam 3 is modulated so that a latent image corresponding to the fourth image information can be formed. Thus, a multicolor image is obtained on the upper surface of the image carrier 1.

Although the operation of the developing units has been described above in the order of the developing units 4, 5, 6, and 7, the developing units 4, 5, 6, 7, and 7 are operated in accordance with the respective image information.
Can be arbitrarily selected.

The multicolor toner image formed on the image carrier 1 as described above is transferred onto the recording material P supplied by the transfer charger 9. The recording material P is separated from the image carrier 1 by the separation and neutralization device 10, and is conveyed to the 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.

[Problems to be Solved by the Invention] However, the above-described conventional example is preferable as a color image forming apparatus, but has a disadvantage that when the toner T is developed on the upper surface of the image carrier 1 and an image overlapping portion is to be exposed, Since the toner T absorbs the exposure light, the surface potential cannot be attenuated accurately in response to the light from the laser light 3, and the adhesion of the toner T becomes difficult. This became more and more difficult as the number of layers of the toner T was increased to two or three in the image carrier 1. As a result, the image was missing or the color tone was unclear.

As a solution to this, a photoconductive layer is provided on a light-transmitting conductive substrate as described in JP-B-61-20960,
There is one that is trying to solve the problem by irradiating light from the light transmitting conductive substrate side.

 However, this proposed method has the following disadvantages.

(1) Due to scattering of the toner T from the developing device and sneaking of foreign matter from the surroundings, the toner T is accumulated in the light-transmitting conductive substrate during long-term image formation, absorbs light from the laser 3 and can reach the photoconductive layer. However, the image is lost, and finally no image can be formed.

(2) When an exposure apparatus such as an LCD head array or an LED head array is used, a self-occ lens array (trade name of Nippon Sheet Glass Co., Ltd.) is usually inserted between the LED array and the image carrier to thereby form a space between the LCD or the LED head. However, the image is condensed by the toner and the foreign matter, and the optical efficiency is extremely lowered, and the recorded image becomes unclear.

(3) Since the optical system is housed inside the image carrier, it is difficult for the user to clean the optical system, requiring specialized knowledge such as experienced persons, and the cost is increased and there is a problem in handling.

For the reasons (1), (2) and (3) above, the above proposed method is not practical any more.

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned points, and the present invention provides an image carrier having a light-transmitting base layer and a photoconductive layer. The provision of the means is intended to prevent the accumulation of toner and foreign matter inside.

Embodiment FIG. 1 is a schematic sectional view of the present invention, and FIG. 3 is a partial sectional view of the image carrier 1 of FIG. In FIG. 3, a cylindrical glass material 13 is used as a light-transmitting conductive base layer, a conductive ITO (indium oxide) 14 is deposited on the outer peripheral surface, and zinc oxide, amorphous silicon, and selenium organic material are further deposited. The image carrier 1 was obtained by coating or vapor-depositing the photoconductive layer 15 such as In this embodiment, an organic semiconductor was used.

The image carrier 1 is mounted on the apparatus shown in FIG. 1 and rotated in the direction of the arrow to cause a high voltage corona discharge in the charger 2 from the high voltage power supply 20 and the potential on the surface of the image carrier 1 to -600 (V). I do.

Next, the first image information is supplied from the image processing circuit 17 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 self-occurrence lens array 18, and the image carrier 1 An electrostatic latent image is formed on the upper surface. The electrostatic latent image is visualized by adhering the toner T ₁ at reverse development as in the second image description.

In the second rotation, the upper surface of the image carrier 1 is supplied from the charger 2 from the high voltage power supply 20 so that the upper surface thereof becomes approximately -650 (V), and the second image information is supplied from the image processing circuit 17 to the LED head array 16. and, imaging the image information light 3 on the image bearing member 1 top through self Oh try lens array 18 from the LED Hetsudoarei 16 creates an electrostatic latent image is adhered to the toner T _2.

Similarly performs third rotation in the third image formed on the image bearing member 1 in a substantially one 700 (V) in the toner T _3, 4 to the second rotation is substantially the image bearing member 1 on -750 (V ) charged in, performing a fourth image formed by the toner T _4.

The multicolor toner images formed in the above process are collectively transferred to the recording material P and fixed as in the description of FIG.

However, as described above, when performing image exposure from the back surface of the image carrier 1, there is a problem that the toner is contaminated by the toner T or foreign matter in the apparatus.

As a solution to this, a pressure increasing means 24 as shown in FIG.
Is arranged inside the image carrier 1 so that the image carrier 1
Is to prevent the rear surface from being stained.

In the present invention, a fan motor 21 is disposed outside the image carrier 1 as the air pressure increasing means 24, and is connected by a duct 19 to increase the air pressure inside the image carrier 1, and the other end of the duct 19 is connected to the image carrier. The present inventor has found that a pressure difference between the inside and outside of the image carrier 1 is generated by providing the image carrier 1 at the center and in the center in the axial direction, and it is possible to prevent toner and foreign matter from entering. .

 Hereinafter, specific examples will be described.

The image carrier 1 is 140 mm in diameter, 2 mm in thickness, and width using the apparatus shown in FIG.
At 260 mm, the fan motor 21 was operated by Sanyo Electric Co., Ltd. model name 109P0824H602 at a rated value and used as a duct with a diameter of 40 mm. It was confirmed that the heating element in the carrier 1, for example, a light emitting element such as a laser diode and an LED, and a light source such as a liquid crystal shutter array also had an effect of cooling.

[Other Embodiments] By arranging an air filter 25 in the vicinity of the fan motor 24 as shown in FIG. 4 in a part of the apparatus in FIG. 1, it is possible to obtain more effects than in the case of FIG. It became.

FIG. 5 shows a polyester film 75 as a transparent conductive film 13 'in place of the glass cylinder of the image carrier described in FIG.
In this case, ITO of the conductive layer 14 is deposited on the upper surface of μm, and the photoconductive layer 15 is applied thereon with a thickness of 25 μm. (See FIG. 6) The image carrier belt 1 is rotated in the direction of the arrow by the driving roller 22 to form an image in the same manner as described with reference to FIG. At this time, as in the case of FIG.
By increasing the internal air pressure, the image formation is not only uniform over a long period of time, but there is no foreign matter mixed between the image carrier 1 and the driving roller 22 or the driven roller 23, and the image carrier 1 and the driving roller Slip can be prevented beforehand,
The peripheral speed of the image carrier can be kept constant.

Although the configurations described above are all described in four colors (the number of developing devices is four), a similar effect can be obtained even in 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 are arranged on the inner surface of the image carrier 1 as the charging and developing devices. The same effect can be obtained by a method in which the image is continuously transferred to the transfer material during the movement.

[Effects of the Invention] As described above, in an image forming apparatus in which exposure is performed from the back side of an image carrier and an air pressure increasing means is provided inside the image carrier, 1. stable over a long period of time. 2. The peripheral speed is constant, so there is no distortion or misregistration of the image. 3. The image does not become unclear.

[Brief description of the 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, FIGS. FIG. 6 is a sectional view showing another embodiment of the present invention. In the figure, 1 is an image carrier, 13 is a light-transmitting base layer, 15 is a photoconductive layer, and 24 is a pressure increasing means.

Claims (1)

(57) [Claims] 1. An electrophotographic apparatus for forming a visible image of a plurality of colors by repeating image formation a plurality of times on an image carrier having a photoconductive layer provided on a light-transmitting base layer, and transferring the formed image to a recording material,
At least one light irradiating means provided on the inside of the image carrier and irradiating optical information according to the image information from the light transmitting base layer side, and having a pressure increasing means provided on the inside of the image carrier. Electrophotographic equipment.