JPS5915945A - Multicolor printing method - Google Patents

Abstract

PURPOSE:To enable satisfactory multicolor printing without mixing colors even if exposing and developing are repeated, by charging electrostatically a photoreceptor again before exposing for the 2nd and succeeding colors. CONSTITUTION:The surface of a photoreceptor 1 is uniformly and electrostatically charged by the 1st electrostatic charger 2, by which the part corresponding to the 1st color is exposed. The part attenuated in the surface potential by the exposure is developed by a developing device for the 1st color. Only the dark attenuated part is electrostatically charged again by the 2nd charger 5 and the part for the 2nd color is exposed by the 2nd exposing part 6. The 2nd exposed part is developed by the 2nd developing device 7. Thereafter, the dark attenuated part is charged again by the 3rd charger 8, and the part corresponding to the 3rd color is exposed by the 3rd exposing part 9. Said part is developed by the 3rd exposing part 9, whereafter the photoreceptor is fed to a transfer device 11 and the image is transferred onto the paper fed from a feed cassette 13. The developer remaining on the photoreceptor 1 is thereafter removed by a cleaning device 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer that is an output device for an information processing device such as a computer, and is capable of printing characters and symbols.

This invention relates to a multicolor glint method in which when printing image output information, the colors of characters, symbols, and images are varied as necessary, and characters, symbols, and images of different colors are printed in a mixed manner on the same sheet of paper.

[Technical background of the invention and its problems]

As the speed of electronic computers increases, the requirements for output devices such as printers include the ability to print at high speed, the device to be small, simple, easy to maintain, and low noise. This is disclosed in an electrophotographic non-impact printer. In this method, the photoreceptor is uniformly charged, exposed to light for a first color and developed for the first color, and then exposed to light for a second color and developed for the second color.

However, in the conventional method, there is no potential level difference between the first color developing section and the second color developing section, and when the second color is developed, the first color is developed again and mixed, resulting in clear multicolor printing. The disadvantage was that it was not possible to do so.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to provide a multicolor printing method that allows multicolor printing without color mixing even after repeated exposure and development. This is what we are trying to provide.

[Summary of the invention]

In the present invention, the surface of the photoreceptor is recharged before exposure for the second and subsequent colors.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2. In the figure, 1 is a photoreceptor for electrophotography, and this photoreceptor 1 is designed to be rotated in the direction of the arrow. Further, chargers 2 and 3 are arranged around the photoreceptor 1 in order along the rotational direction thereof. First exposure section 3. First color developer 4, second charger 5. Second exposure section 6. Second color developer 7. Third charger8. A third exposure section 9, a third color developing device 10, a transfer device 1, and a cleaning device 12 are provided. The first to third exposure sections 3.6.9 are constituted by, for example, a laser beam, an optical fiber, a cathode ray tube, or a light emitting diode array.

Therefore, in the above-described configuration, when performing multicolor printing, the surface of the photoreceptor 1 is first uniformly charged by the first charger 2. Then, the surface of the charged photoconductor 1 is exposed to the first exposure section 3 as shown in FIG.
As shown in b), the first color print information is exposed. The surface potential of the exposed area is attenuated, the potential remains in the unexposed area, and the developer 4 for the first color is applied with developer as shown in FIG. 3(b). It is supplied and developed. This developing method is called a reversal developing method in electrophotography, and can be performed by using toner having the same polarity as the surface potential of the photoreceptor and applying an insulating pressure of the same polarity to the developing device. Next, the surface of the photoreceptor 1 is recharged by the second charger 5 by the amount of dark decay as shown in FIG. The information to be printed in the second color is exposed. The exposed portion is supplied with a developer by the second color developing device 7, as shown in FIG. 3(f), and is developed. After the second color development is carried out in this way, the surface of the photoreceptor 1 is charged again by the third charger 8 as shown in FIG. 9, the information to be printed in the third color is exposed. The exposed portion is supplied with developer by the third color developing device 10 and is developed. The multicolor developed image is then sent to the transfer device 1, where it is transferred onto a sheet of paper fed from the paper feed cassette 13. Further, after the transfer, the developer remaining on the photoreceptor 1 is removed by IJ-coating in the cleaning device 12.

As mentioned above, during multicolor development, the surface of the photoreceptor is recharged before exposure to the second and subsequent colors, so the potential of the area exposed to the second color is lower than the potential of the development area of the first color. Furthermore, the potential of the exposed portion of the third color is lower than the potential of the developing section of the second color.

Therefore, when developing the second color, the first color developing area may reproduce the image and cause color mixture, or when developing the third color, the first color developing area may reproduce the image and cause color mixture.
Also, it is reliably prevented that the second color developing section is reproduced and mixed.

〔Effect of the invention〕

As described above, the present invention is a method for printing multiple colors by repeating exposure and development steps on the surface of a uniformly charged photoreceptor, in which the photoreceptor is recharged before exposure for the second and subsequent colors. Therefore, it is possible to provide different potential levels in the developing portions of each color, and there is no color mixing as in the conventional method, and there is an effect that clear multicolor printing is possible.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic diagram showing the inside of the printer, FIG. 2 is a chart showing the process during image formation, and FIGS. 3 (A) to (G). is a graph diagram showing changes in surface potential of a photoreceptor. 1... Photoreceptor, 2.5.8... Charger, 3,6°9
...Exposure section, 4,7.10...Development section.

Claims (1)

[Claims] In a method of performing multicolor printing by repeatedly exposing the surface of a uniformly charged photoreceptor and developing it,
A multicolor printing method characterized by recharging the photoreceptor before exposure of colors and subsequent colors.