JPS62249176A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To provide an optical printer function which permits an effective use of the existing photosensitive material to a copying machine by using an exposing device for which an electroluminescence element array is used as an exposing device for an optical printer. CONSTITUTION:The exposing device A for the optical printer consisting of the electroluminescence element array 1 and a multilens array 2 and the exposing device B for the copying machine consisting of an original platen 14, a blue lamp 16 for illuminating an original and an optical system 17 for condensing the reflected light from the original are disposed around a cylindrical photosensitive drum 3. The electroluminescence element can set the emission wavelength to a desired wavelength when the constituting material thereof is adjusted. The sharp and good image is, therefore, printed at a high speed with the existing photosensitive material by using the electroluminescence element and flickering the same in accordance with the data from an printing control circuit to expose the image.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an exposure means of an electrophotographic apparatus such as a copying machine or an optical printer.

Conventional technology Copying machine technology has now reached an extremely advanced stage, and the development of highly sensitive materials for photosensitive drums and photosensitive belts has made it possible to obtain clear and good quality copied images. It has become.

On the other hand, with the spread of facsimiles and other information processing devices in recent years, optical printers for outputting images tend to become widespread. This optical printer is mechanically different from the above-mentioned copying machine only in the structure of the exposure device, and the charging device, photosensitive drum, developing device, transfer device, etc. are technically the same as existing copying machines. Can be used for other purposes. However, in optical printers designed to be smaller and lighter, the emission wavelength is 780 to 790 nm.
Due to the use of semiconductor lasers, selenium (S
The s) type photosensitive material is not suitable for use due to insufficient exposure. Therefore, conventionally, as a photosensitive material for optical printers,
S e -A with its peak sensitivity sensitized to the long wavelength side
S-based material is used, and He-Ne is used as a laser device.
Attempts have been made to use short wavelength devices such as lasers.

Problems to be Solved by the Invention When a He-Ne laser device is used as an exposure light source for an optical printer, there are disadvantages in that the manufacturing cost of the optical printer increases and power consumption increases. Furthermore, SeAs-based photosensitive materials that have been sensitized to long wavelengths currently only have a sensitivity of about 172 to 115 compared to the sensitivity of Se-based photosensitive materials. Si
A type of photosensitive material has been developed, but its spectral sensitivity is 6.
Since it has a peak around 80 nm, maximum efficiency cannot be obtained even if a semiconductor laser is used.

As is clear from the above, for optical printers, the sensitivity of the photosensitive material is related to the recording speed, so it is desirable to match the emission wavelength of the exposure light source with the photosensitive wavelength of the photosensitive material. As long as a laser device is used, at present it is necessary to develop a photosensitive material that has high sensitivity in a long wavelength region, but the current situation is that such development is difficult.

Purpose of the Invention The present invention has been proposed in order to suitably solve the problems inherent between the exposure light source and the photosensitive material in optical printers, and uses a laser device as the exposure light source. It is an object of the present invention to provide an electrophotographic apparatus having an optical printer function that can effectively utilize conventional photosensitive materials developed for copying machines.

Means for Solving the Problems In order to overcome the above-mentioned problems and suitably achieve the intended purpose, the present invention provides an exposure device that forms a desired electrostatic latent image on a charged photoreceptor, and an electrostatic An electrophotographic apparatus including a developing device that converts a latent image into a visible image and a transfer device that transfers the visible image onto a sheet of paper is characterized in that an electroluminescent element array is used as an exposure device.

The working electroluminescent device can set one emission wavelength to a desired wavelength by adjusting its constituent materials.For example, when an electroluminescent device is made of ZnS:Cu:C1:Tm, its emission wavelength can be set to a desired wavelength. The peak wavelength is around 450 to 480 nm. Therefore, by configuring an exposure device using such an electroluminescent element, it becomes possible to print clear and good images at high speed using existing photosensitive materials.

Embodiment Next, a preferred embodiment of the electrophotographic apparatus according to the present invention will be described with reference to FIG.

FIG. 1 is a block diagram of an electrophotographic apparatus according to an embodiment of the present invention. The electrophotographic apparatus of this embodiment has both an optical printer function and a copying function, and has a cylindrical shape. A selenium-based photosensitive material is coated on the entire outer peripheral surface of the photosensitive drum 3. Around this photosensitive drum 3, an exposure device A for an optical printer consisting of an electroluminescent element array 1 and a multi-lens array 2 made of a material to be described later, a document table 14, a blue lamp 16 for document illumination, and a document light source are placed. An exposure device B for a copying machine is arranged, which includes an optical system 17 that collects reflected light. Furthermore, around this drum 3, there is a developing device 5 containing charged toner, a transfer device 10, and a cleaning device 11.

A static elimination lamp 12 and a charger 13 are sequentially arranged in the drum rotation direction (clockwise in the illustrated example).

The electroluminescent element array 1 is connected to a print control circuit (not shown) via a drive circuit and an interface circuit (not shown), and is turned on and off based on a data signal from the print control circuit. Movable light-shielding plates (not shown) are disposed before and after the optical system 17 of the exposure device B for a copying machine, and when the electrophotographic apparatus of the present invention is used as an optical printer, the light from the optical system 17 is This is to prevent the light from leaking to the photosensitive drum 3 side by being blocked by the light shielding plate.

Reference numerals 6 and 7 indicate paper feed drive rollers, and the paper 8 is fed by these rollers 6 and 7 and supplied between the transfer device 10 and the photosensitive drum 3.

The electroluminescent elements constituting the array 1, which is the exposure bag [A] of the optical printer, are made of, for example, ZnS or CaS.
It is formed by adding various additives (often rare earth elements) to the base material. Examples of element materials and emission peak wavelengths obtained from them are listed below.

ZnS: Cu: C1: Tm
~480nm ZnS: TbF
, ~550nm ZnS: M
n ~580nIICaS
: Eu : C1~650nmCaS :
Ca: C1 to 550 nm As described above, electroluminescent elements have different emission wavelengths depending on their materials.

The above examples were all selected based on the peak sensitivity of existing photosensitive materials. Therefore, it is easily possible to optimally set the combination of the material of the electroluminescent element and the photosensitive material used for the photosensitive drum 3.

Next, the operation of the electrophotographic apparatus shown in FIG. 1 will be explained.

When using the electrophotographic apparatus as an optical printer, the light shielding plate in the optical system 17 is closed. Photosensitive drum 3
is uniformly charged at a location facing the charger 13, and as the drum rotates, the charged location comes to the front of the multi-lens array 2. When the electroluminescent element array 1 blinks in response to a data signal, the charge at the portion of the charged portion that is hit by light escapes, forming a dot matrix-like electrostatic latent image. Charged toner is attached to this electrostatic latent image portion by a developing device 5, and then the toner on the drum 3 is transferred by a transfer device 10 onto a sheet 8 inserted in the direction of an arrow 9. The residual toner on the drum 3 is removed by a cleaning device 11.
The static electricity is removed by the static elimination lamp 12 and initialized. The same process is repeated thereafter.

Further, when the electrophotographic apparatus is used as a copying machine, the light shielding plate is left open. Under the illumination of the lamp 16, the document table 14 on which the document is placed moves in the direction of arrow 1 in accordance with the rotation of the drum 3.
When moving in the five directions, an electrostatic latent image is formed on the drum 3 in the same manner as described above.

Thereafter, the copy image is transferred onto the paper 8 in the same manner as in the case of an optical printer.

In this embodiment, since the electroluminescent element array 1 and the lamp 16 are selected according to the peak photosensitive wavelength of the photosensitive material used for the photosensitive drum 3, the printed image
Both copy images can be obtained clearly and at high speed. Furthermore, as is well known, the electroluminescent element can be driven with a low current, thereby saving energy. Additionally, because it does not use a laser scanning method that requires many moving mechanisms, it has excellent durability and accuracy.

According to the present invention, it is possible to select an exposure light source for an optical printer and an exposure light source for a copying machine according to the photosensitive material, so in this embodiment, the case where a combined function of an optical printer and a copying machine is provided is described. As mentioned above, it goes without saying that it is also effective when used as a standalone optical printer.

Effects of the Invention According to the present invention, since the exposure light source for an optical printer can be selected in accordance with the photosensitive material, it is possible to print clear and good images at high speed. Furthermore, since the number of mechanically movable parts is reduced, durability and precision are improved, and further energy savings can be achieved. Further, it is possible to easily combine the combined functions of an optical printer and a copying machine.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electrophotographic apparatus according to an embodiment of the present invention. 1... Electroluminescent element array 2... Multi-lens array 3... Photosensitive drum 5... Developing device 10...
Transfer device 13... Charger 14... Original table
16...Lamp 17...Optical system

Claims (1)

[Scope of Claims] [1] An exposure device that forms a desired electrostatic latent image on a charged photoreceptor, a developer that converts the electrostatic latent image into a visible image, and transfers the visible image onto paper. What is claimed is: 1. An electrophotographic apparatus comprising a transfer device that uses an electroluminescent element array as the exposure device. [2] The exposure device using the electroluminescent element array is used as an exposure device for an optical printer, and an exposure device for a copying machine is separately provided, and either one of the exposure devices is selectively switched and used. An electrophotographic apparatus according to claim 1, characterized in that: [3] The emission wavelength of the electroluminescent element is
An electrophotographic apparatus according to claim 1 or 2, wherein the electrophotographic apparatus is adapted to a sensitivity wavelength of the photoreceptor.