JPH06122234A - Electrophotographic color printer - Google Patents

Abstract

PURPOSE:To enable execution of printing of high speed and high grade by a simple mechanism. CONSTITUTION:Means for charging, exposure and development are provided. These means are constructed of one charger 2, one set of optical system 3 executing total exposure, half-exposure and non-exposure and two monochromatic developers 5 and 6 respectively and these component devices are disposed in series for a photosensitive body belt 1. Being linked to these component devices disposed in series, moreover, another train of devices comprising one charger 6, one set of optical system 7 executing total exposure, half-exposure and non-exposure and two monochromatic developers 8 and 9 are disposed in series.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic color printer, and more particularly to an electrophotographic color printer capable of high speed and high quality printing. In particular, it is used for unifying data of personal computers, workstations, and general-purpose computers, for example.

[0002]

2. Description of the Related Art In a conventional electrophotographic color printer, it is necessary to repeat the printing process for each color. Below, FIG.
The conventional technique will be described with reference to FIG.

FIG. 3 is an illustration of a conventional electrophotographic color printer (hereinafter referred to as a printer). Figure 3
In FIG. 3, 31 is a photoconductor belt, 32 is a charger, 33 is an exposure optical system, 34 is a color developing machine (yellow), 35 is a color developing machine (magenta), 36 is a color developing machine (cyan), and 37 is a developing machine. (Black), 38 is a cleaner, 3
9 is an eccentric cam, 40 is a restoring spring, 41 is a paper hopper, 4
2 is a printing paper, 43 is a pitch-up roller, 44 is a feed roller, 45 is a transfer / separation corotron, 46 is a conveyor belt, 47 is a heat roller, 48 is a pressing roller, and 49.
Is a stacker.

First, the surface of the photosensitive belt 31 is
It is charged to about 700V by the charger 32. Next, LE
An exposure optical system 33 composed of a D print head or the like exposes the print data to form a latent image. Subsequently, a color developing machine (yellow) 34 develops yellow. At this time, the cleaner 38 is in the retracted state by the action of the eccentric cam 39 and the restoring spring 40.

Again, the charging device 32 charges the surface uniformly, and the latent image is formed by exposure according to the print data relating to magenta. Color developing machine (magenta) 35
Thus, magenta development is performed. Similarly, development of cyan and black is also performed. That is, charging,
The process of exposure and development is repeated four times to complete color development. Before completing the color development, the paper hopper 41
The printing paper 42 is fed out by the pitch-up roller 43, and is pushed out by the feed roller 44 at a timing matching the printing position.

Next, a high voltage is applied to the transfer / separation corotron 45 to transfer the color toner image on the photosensitive belt 31 onto the printing paper 42. Further, the transfer / peeling corotron 45 peels the printing paper 42 to the photosensitive belt 3
1 is separated from the heat roller 47, is placed on the conveyor belt 46, and is fed between the heat roller 47 and the pressing roller 48.
The color toner image on the printing paper 42 is fixed by the heating by and the pressing by the pressing roller 48. The printing papers 42 on which the color toner images have been fixed are stacked on the stacker 49.

As described above, in the printer, monochrome printing is completed once, whereas in color printing, charging,
It is completed by repeating exposure and development four times. After the transfer and peeling corotron 45 transfers the color toner image onto the printing paper 42, the photosensitive belt 31 advances to the cleaner 38.
At this time, the eccentric cam 39 works against the restoring spring 40,
The cleaner 38 is brought into contact with the photosensitive belt 31. The cleaner 38 rotates to clean the untransferred toner remaining on the photosensitive belt 31. The photosensitive belt 31 advances to the charger 32 in preparation for the next printing, and the printing is repeated in the same manner. Thus, with conventional printers, when performing color printing,
There is a drawback that it takes a longer time to complete printing compared to monochrome printing.

[0008]

The conventional printers described above have a problem that the time required to complete color printing is longer than that in monochrome printing, which is not compatible with the environment in which the computer printer is used. The environment surrounding computer printers has the momentum of unifying data specifications from personal computers and workstations to general-purpose computers. Also, it is an era in which many kinds of computers and peripheral devices are connected and operated by a network. Therefore, there has been a demand for a printer that can print freely from a personal computer, workstation to a general-purpose computer, and can print both monochrome and color.

The present invention has been made to solve the above-mentioned problems of the prior art, and can perform both monochrome and color printing. In particular, color printing can be performed at a high speed and with a simple mechanism. It is an object of the present invention to provide an electrophotographic color printer capable of high quality printing.

[0010]

In order to achieve the above object, the structure of a printer according to the present invention comprises means for charging, exposing and developing, each means comprising one charger. It consists of a set of optical system for performing full exposure, half exposure, and non-exposure, and two monochromatic developing machines. The above-mentioned constituent devices are arranged in series with respect to the photoconductor, and the series arranged in series. The two components are connected in series.

That is, for the above-mentioned purpose, if a series of equipments including a charging device, an exposure optical system and a developing device are arranged in series with respect to the photoconductor, printing can be performed in one pass. It is achieved formally. However, it is technically meaningless because the printer becomes large and the cost becomes high. Therefore, focusing on the fact that there are regular development (adhering toner to the non-exposed portion) and reversal development (adhering toner to the exposed portion) in the developing action of electrophotography, in one exposure, the regular developing portion Negatively charged toner,
The positively charged toner is attached to the reversal developing portions.

[0012]

The function of each of the above technical means is as follows.
According to the structure of the present invention, each charging, exposing, and developing means comprises one charger, a set of optical system for performing full exposure, half exposure, and non-exposure, and two monochromatic developing machines, and these are used as photoreceptors. In contrast, since they are arranged in series, and these are connected in series, two colors can be carried out by one charging operation, and development up to two colors can be carried out by one exposure operation. That is, charging, exposure, and development necessary for printing the three primary colors and black are performed by one printing process, and high-speed printing is possible.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is an explanatory view of a printer according to an embodiment of the present invention, and FIG. 2 is an explanatory view of a distribution of a photosensitive member surface potential of the printer shown in FIG.

In FIG. 1, 1 is a photoreceptor belt, 2 is a charger A, 3 is an exposure optical system A, 4 is a color developing machine A (yellow), 5 is a color developing machine B (magenta), and 6 is a charger. B and 7 are exposure optical systems B, 8 is a color developing machine C (cyan), 9 is a black toner developing machine, 10 is a cleaner, 11 is a paper hopper, 12 is a printing paper, 13 is a pitch-up roller, 14 is a feed roller, Reference numeral 15 is a transfer / peeling corotron, 16 is a conveyor belt, 17 is a heat roller, 18 is a pressing roller, and 19 is a stacker.

As shown in FIG. 1, the photoconductor belt 1 is located at the substantially central portion of the printer and is rotated in a triangle by three rollers. On one side of the triangle of the photoconductor belt 1 (on the left side in FIG. 1), a charger A2, an exposure optical system A3, and a color developing machine A are provided.
(Yellow) 4 and a color developing machine B (magenta) 5 are sequentially arranged from the lower side to the upper side along the belt traveling direction of the photosensitive belt 1.

A charging device B6, an exposure optical system B7, a color developing device C (cyan) 8, and a black toner developing device 9 are provided on the opposite side of the photosensitive belt 1 (on the right side in FIG. 1). The body belts 1 are sequentially arranged from the upper side to the lower side in the belt traveling direction. On the remaining one side of the triangle of the photosensitive belt 1 (lower side in FIG. 1), the paper hopper 11, the pitch-up roller 13, the feed roller 14,
A transfer / separation corotron 15, a conveyor belt 16, a heat roller 17, a pressing roller 18, and a stacker 19 are sequentially arranged from the right side to the left side along the belt traveling direction of the photosensitive belt 1. Further, the printing paper 12 is the paper hopper 11
It is stored in.

The operation of this embodiment will be described with reference to FIG.
As shown in (1) of FIG. 2, the charging potential Vs on the surface of the photosensitive belt 1 is charged to V01, about 700V by the charger A2. As shown in FIG. 2B, the exposure optical system A
In No. 3, among the three primary colors, the portion where the print data of yellow is present is completely exposed, and the portion where the print data of magenta is present (non-exposed) is half-exposed. This exposure optical system A3
Is controlled by the logical sum of the yellow print signal (reverse development in this embodiment) and the magenta print signal (normal development in this embodiment).

The charging potential Vs disappears in all exposed portions,
V21, drops to 30-80V. The semi-exposed part has an initial potential V01 of about half V11, about V11, 300 to 40.
It becomes 0V. In the non-exposed area, the charge disappears in the process from the exposure optical system to the developing machine, so V01 ', about 670V
Is. All exposed parts are color developing machine A (yellow) 4
Bias potential VB12, about 200V
Since it is applied, an electric field in the negative direction acts on it, and attracts the positively charged toner.

In the non-exposed area, a bias potential VB11 of about 500 is applied to the developing roll of the color developing machine B (magenta) 5.
Since V is applied, an electric field in the positive direction acts on this, and attracts the negatively charged toner. Color mixing can also be carried out using these. FIG. 2 (3) shows these situations.

Next, the surface potential Vs of the photosensitive belt 1 is again determined.
Is uniformly charged to about 700 V by the charger B6.
As shown in (4) of FIG. 2, cyan is developed by the color developing device C (cyan) 8 and black toner is developed by the black toner developing device 9 in the same manner as in the case of yellow and magenta described above. After the development of the three primary colors and black is completed, the photosensitive belt 1 transfers the toner image to the printing paper 12 sent from the feed roller 14 at the transfer / peeling corotron 15, and removes the residual toner by the cleaner 10, Prepare for printing.

The printing paper 12 on which the toner images of the three primary colors and black have been transferred is fed by the conveyor belt 16 and heated between the heat roller 17 and the pressing roller 18.
The toner image is fixed by being pressed. The printing papers 12 on which the toner images are fixed are stacked on the stacker 19. The predetermined print color has one color distributed to each dot, and is generated by an appropriate distribution of these. The primary colors of the respective dodds are formed by the toners of the respective colors being appropriately melted and mixed by heating and pressing in the fixing section.

[0022]

As described above in detail, according to the present invention, it is possible to provide an electrophotographic color printer having a simplified mechanism, capable of high-speed and high-quality printing.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a color printer according to an embodiment of the present invention.

FIG. 2 is a distribution explanatory view of a photosensitive member surface potential of the printer shown in FIG.

FIG. 3 is an explanatory diagram of a conventional electrophotographic color printer.

[Explanation of symbols]

 1 Photoreceptor Belt 2 Charging Device A 3 Exposure Optical System A 4 Color Developing Machine A (Yellow) 5 Color Developing Machine B (Magenta) 6 Charging Device B 7 Exposure Optical System B 8 Color Developing Machine C (Cyan) 9 Black Toner Development Machine 10 Cleaner 11 Paper hopper 12 Printing paper 13 Pitch up roller 14 Feed roller 15 Corotron 16 Conveyor belt 17 Heat roller 18 Pressing roller 19 Stacker

Claims (1)

[Claims] 1. An electrophotographic color printer comprising charging, exposing and developing means, wherein the charging means comprises a single charger, and the exposing means performs full exposure, half exposure and non-exposure. The developing means is composed of two monochromatic developing machines, the charging means, the exposing means and the developing means are arranged in series with respect to the photoconductor, and are arranged in series. An electrophotographic color printer characterized in that the series of means described above are connected in series.