JPS61151560A - Multicolor electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To facilitate the arranging of a developing device without making it large- size and to reduce the cost by arranging individual developing devices successively so that developing members are confronted with a part where a sensitive body is approximately horizontal. CONSTITUTION:An endless belt sensitive body 30 is used as the sensitive body, and developing devices 31-34 of four colors, namely, yellow, magenta, cyan, and black are formed with the same shape and the same structure and are arranged in order so that developing sleeves 31a-34a are brought into contact with the horizontal surface part of the photosensitive belt 30. The photosensitive belt 30 is stretched around a driving roll 40 and three following-up rolls 41 and is turned in the direction of an arrow. The photosensitive belt 30 is so arranged that its part facing developing sleeves of four developing devices 31-34 having the same shape is one horizontal plane, and the peripheral length of the belt 30 is longer than that of a photosensitive drum 10, and two image segments are formed. Electrostatic latent images due to two kinds of color separation light are formed successively during one rotation and are developed with toners of complementary colors of color separation filters and are transferred on the same transfer paper 17, which is wound around a transfer drum 15, superposedly thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a multicolor electrophotographic copying machine using a color separation image superimposition transfer method.

As a prior art multicolor electrophotographic copying machine, one using a color separation image superimposition transfer system is well known. The outline of this typical three-color separation image superimposed transfer type multicolor electrophotographic copying machine is explained with reference to FIG. is illuminated by an exposure lamp 4, and its reflected light is reflected by a first mirror 5, a second mirror 6,
An image is formed on the photoreceptor drum 10 by the exposure optical system consisting of the third mirror 7, the image forming lens 8, and the fourth mirror 9.

The exposure lamp 4 and the first mirror 5 move together parallel to the document at a constant speed V, and the second and third mirrors 6.7 move together synchronously at a speed V2, and the photoreceptor drum 10 Exposure scanning is performed by rotating at a circumferential speed V, and an electrostatic latent image corresponding to the original image is formed on the photosensitive drum 10. In the middle of the exposure path, there are color separation filters 111 for the three primary colors of light, blue, green, and red.
A filter unit 11 is provided that rotates so that it can be switched and inserted into the optical path.The photosensitive drum 10 is rotated three times, the scanner is moved back and forth three times, and exposure scanning is performed three times. IIB, liG,
The mode is switched to IIR' and the document is inserted into the main receiver, and the color-separated images of the original are sequentially exposed to the photoreceptor drum to form three different latent images on the photoreceptor one after another.

Around the photoreceptor drum 10, following the exposure position, developing devices 12, 13, each having a developer containing toner of three colors yellow, magenta, and cyan, which are the three primary colors of the subtractive color method, are provided.
14 are arranged in sequence, blue, green, and red filters
a * 1iGv IIRk The latent images formed by the transmitted light rays are developed with yellow, magenta, and cyan developer, which are complementary colors to the filter colors, respectively, and toner images of those colors are formed on the photoreceptor. . The toner images of each color are fed from a paper feed section 16 to a transfer drum 15 provided in contact with the photoreceptor drum 10 at a position after the three developing devices, and the leading edge is removed by a clamper 18 provided on the transfer drum 15K. The images are transferred onto the transfer paper 17 which is clamped and wound around the transfer drum 15 in a superimposed manner by the action of the transfer charger 19.

When the transfer of the three-color toner image is completed, the clamper 18 opens, and the transfer paper is separated from the transfer drum 15 by a separation charger and a separation claw (not shown), sent to the fixing device 20, where it is fixed, and then transferred to the paper output tray 21. When performing variable magnification copying, the lens 8 and the second and third mirrors 6 and 7 are moved a predetermined distance according to the magnification m, and a copy corresponding to the original is created. By moving the scanner at speed a copy of the required magnification is made.

In addition, in order to efficiently copy black-and-white originals and improve the contrast of color copies, a black developer is installed in addition to the three-color developer described above, and a four-color separation method is used that performs four exposures during color copying. Color copiers are also known.

During image formation for black development, a sho filter or a yellow filter is used as a filter.

Now, as mentioned above, in a multicolor copying machine that uses a drum photoreceptor and rotates it once for each image formation, there are three to four photoreceptors.
The developing devices 12, 13, and 14 must be arranged between one light position around the photosensitive drum IO and the transfer position. Therefore, the shape and structure must be changed for each color developing device, which increases costs and also changes development conditions.

Moreover, toner on the upstream side scatters on the downstream side, causing color mixing. When four developing units are provided, the conditions become even worse.

Therefore, the diameter of the photoreceptor drums was increased to three or four.
Image segments are formed on the circumferential surface of one photoreceptor drum, and the photoreceptor drum is rotated once for three to four exposure scans, and the transfer drum is rotated three to four times to perform superimposed transfer. A multicolor copying machine has also been proposed. Although this makes it easier to arrange the developing units, it is not possible to make the structural shape of each developing unit the same, and there are problems with color mixing due to toner on the upstream side scattering to the downstream side, as well as residual problems and problems with the photoreceptor drum. As the diameter becomes larger, the entire device becomes larger and the cost increases.

Purpose The present invention eliminates the above-mentioned drawbacks of the conventional multicolor electrophotographic copying machine using the color separation image superimposition transfer method, does not increase the size of the device, makes it possible to easily arrange the developing device, and to reduce costs. The purpose of the present invention is to provide a multicolor electrophotographic copying machine.

Structure In order to achieve the above object, the present invention uses an endless belt-like photoreceptor that is passed around a group of rollers, and develops the photoreceptor so that the surface corresponding to the development position by each developer becomes one generally horizontal plane. Each developing device is sequentially arranged with a developing member facing a generally horizontal portion of the photoreceptor.

The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a diagram showing an embodiment of the present invention, and the difference from the conventional apparatus shown in FIG. The four color developing units 31, 32, 33, and 34 are made to have the same shape and structure, and are arranged in order so that the developing sleeves 31a, 32a, 33a, and 34a are in contact with the horizontal surface of the photoreceptor bell 30. This is what is happening. The rest of the structure is the same as the device shown in FIG. 3, so the same members are given the same reference numerals. Paper feed section 16
Although the paper feed table is in two stages, this is not relevant to the present invention. Although not shown in FIG. 3 YC, the photoreceptor 3
A charger 35 and an eraser 36 are provided on the upstream side of the exposure section, and a cleaning device 37 and a static elimination charger 38 are provided on the downstream side of the transfer section.

The photoreceptor belt 30u is supported by the drive roller 40 and three driven rollers 41 and rotated in the direction shown by the arrow. Four isomorphic developments b31.32.

The parts of the belts 33 and 34 facing the developing sleeve are arranged in one horizontal plane, and the belt is 300 circumferences long.
Longer than the circumference of photoreceptor drum ■0 in the device shown in the figure,
Two image segments can be formed. Therefore, in this apparatus, the photoreceptor belt 30 rotates once for every two document exposure scans.

However, the transfer drum 15 rotates once for one exposure scan. Therefore, during one rotation of the photoreceptor belt 300, electrostatic latent images using two types of color-separated light are sequentially formed on the photoreceptor belt, each developed with toner of the complementary color of the color-separation filter, and wound onto the transfer drum 15. The images are superimposed and transferred onto the same transfer paper 17. Therefore, when performing three-color superimposition transfer to obtain a multicolor copy, the photoreceptor belt 30 is rotated once and a half, and when four colors are superimposed, the photoreceptor belt 30 is rotated twice.
Rotate. Other operations are the same as the conventional device shown in FIG.

Since this device has the above-described configuration, the four developing devices 31, 32, 33, and 34 can be easily arranged and can be made to have the same shape and structure, so that the developing conditions can be uniform. In addition, it is possible to reduce costs from a manufacturing perspective. Since the developing sleeves of the four developing devices are in contact with the photoreceptor belt 30 on one generally horizontal plane, toner on the upstream side is prevented from scattering to the downstream side and causing color mixing. Although the circumference of the photoreceptor was made longer in order to facilitate the placement of the developing unit, the photoreceptor was made into an endless belt, which enabled it to be made into a flat shape, making the entire photoreceptor larger. All that can be avoided.

Photoreceptor belt 30C, a row 24 that wraps around and supports the photoreceptor belt 30C
0 and 41 to form a cartridge, it is possible to easily attach and detach the photoconductor from the main body of the copying machine during maintenance, inspection, and replacement.

FIG. 2 is a diagram showing an embodiment of the pond of the present invention.

The difference between this embodiment and the embodiment shown in FIG. 1 is that a cylindrical intermediate transfer member 50 having the same outer diameter is provided in place of the transfer drum 15 for winding transfer paper, and toner images of three or four colors are provided. are superimposed and transferred onto this intermediate transfer body 50, and transferred to the transfer paper 17 fed by the paper feed section 16 between the transfer charger 51 and the intermediate transfer body 50, which are provided opposite to the peripheral surface of the intermediate transfer body 50. Three to four color superimposed toner images are transferred at once, separated by a separation charger 52, and transferred to a fixing device 2 by a conveyor belt 53.
0, is fixed, and is ejected to a paper ejection tray 21. In this device, the toner image formed on the photoreceptor belt is transferred to the intermediate transfer member 50 and then to the transfer paper 17, so that the exposure optical system is used to prevent the image on the copy from becoming a reverse image. It is necessary to provide a fifth mirror 9' in , and increase the number of mirrors 2- by one. Due to this, the position of the color separation filter 11 has moved slightly. Other configurations and effects are the same as in the previous embodiment.

Effects As described above, according to the present invention, the arrangement of a plurality of developing devices is
Since the shape and structure of each developing device can be completely the same, costs can be reduced. or,
Since the development position of each developing device is on one horizontal plane, toner on the upstream side does not scatter downstream and cause color mixing.

In addition, since the photoreceptor is shaped into an endless belt and made flat, the entire device, especially its height, can be made smaller, allowing it to be made into a desk type, and it is equipped with a black developing device, making it possible to make black and white copies more efficient. In addition to this, in recent years there has been a trend of people wanting to change colors in conventional black-and-white copiers (office copiers), and copiers with this configuration are also capable of multi-color copying, making it possible to make multi-color copies instead of conventional color copying machines. The machine can be made suitable for office copying machines.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the overall configuration of a multicolor electrophotographic copying machine according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, and FIG. 3 is a conventional color separation image superimposition method. 1 is a sectional view showing a schematic configuration of a transfer type multicolor electrophotographic copying machine. 3... Original 15... Transfer drum 17.
...Transfer paper 19151...Transfer charger 30...Endless belt-shaped photoreceptor 31-34...Developer

Claims (3)

[Claims] (1) Each one of the developing devices each holding a developer of a different color is used to form a latent image corresponding to each separated light formed by sequentially exposing a color separated light image of an original onto a single photoreceptor. In a multicolor electrophotographic copying machine that creates a color copy by sequentially developing toner images of different colors onto the same transfer paper, the above-mentioned photoreceptor corresponds to the development position by each of the above-mentioned developing devices. It is an endless belt-like photoreceptor stretched over a plurality of rollers so that its surface forms one generally horizontal plane, and each of the above-mentioned developing devices has a developing member facing a generally horizontal portion of the photoreceptor belt. A multicolor electrophotographic copying machine characterized by sequential arrangement. (2) The endless belt-like photoreceptor described above is housed in a housing together with a roller around which it is wound, and is a cartridge that is removably attached to a copying machine. Multicolor electrophotographic copying machine. (3) The multicolor electrophotographic copying machine according to claim 1, wherein the plurality of developing units have the same shape and structure.