JPH0413710B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Technical field The present invention relates to an electrophotographic device, particularly an electrophotographic device that exposes and develops a plurality of images on a drum or belt-like photoreceptor and transfers them to a transfer material such as paper. This is used in a multicolor electrophotographic device that allows you to select colors. (B) Prior Art A conventional electrophotographic apparatus uses one light source and one photoreceptor for one image exposure. Therefore, when multicolor electrophotography is required, it is necessary to prepare as many light sources and photoreceptors as there are colors and apply the colors one after another, or to expose and develop the photoreceptors and transfer them to the transfer material. By repeating this process a necessary number of times, the colors are applied over and over to obtain a desired multicolor electrophotograph. However, in the former case, the device becomes larger and
The disadvantage is that maintenance is time-consuming due to the large number of parts, and the latter has the disadvantage that accurate superimposition of images is difficult and processing time is long. Therefore, we would like to create a multicolor electrophotographic device that not only can obtain multicolor electrophotography with a small number of light sources and photoreceptors, but also allows for easy color selection, which is relatively easy with conventional devices. There is a demand for this. The present applicants previously filed Japanese Patent Application No. 59-005323 in order to meet such demands. This consists of an electrophotographic section and a scanning optical system. A second exposure section, a first developing device, an entire surface exposure section, and a second developing device are sequentially provided, and in the scanning optical system, one laser beam emitted from a laser transmitter is used to print two different images using a modulator. This laser beam is split by a deflector into light beams each carrying the image signals of two images, and these lights are then scanned by a scanning device to scan the first and second beams on the photoreceptor. The light beams are made to be incident on the respective exposed areas. However, when using this device for exposure and development, if you try to develop three or more colors, two photoreceptors are required, which not only increases the size of the device, but also makes it troublesome to periodically control the rotation speed of the photoreceptors. It turns out that there is a drawback. (c) Purpose of the invention The present invention provides a method for exposing and developing three or more colors.
It is an object of the present invention to provide an electrophotographic apparatus that uses one photoreceptor, does not require synchronous control of the photoreceptor, and can select the color to be printed. (d) Configuration of Embodiments The present invention will be described in detail below based on drawings showing embodiments thereof. In FIG. 1, reference numeral 1 denotes a photoreceptor, which has a structure including three layers and a photosensitive layer. Reference numeral 2 denotes a pre-exposure section, which provides uniform light onto the photoreceptor 1 to eliminate potential irregularities. A first charger 3 charges the photoreceptor 1 with one polarity, and a direct current type is generally used. Reference numeral 4 denotes a second charger for charging the photoreceptor 1 with the other polarity, and in the embodiment, a type that superimposes a direct current on an alternating current is used. 5 is a first exposure section that has an optical axis passing through the second charger 4 and is capable of exposing an image signal of a first color; 6 is a first exposure section that is capable of exposing an image signal of a second color. This is the second exposure section. Reference numeral 7 represents a first developing device capable of developing the image signal of the second color, and reference numeral 8 represents a third charging device capable of recharging the photoreceptor 1 to the other polarity. 9 is a third exposure unit capable of exposing an image signal of a third color; 10 is a second developing device capable of developing an image signal of a third color; It is desirable to use a so-called jump developing device, which allows development to be carried out without deterioration. Reference numeral 11 denotes a full-surface exposure section capable of exposing the photoconductor 1, and 12 a third developing device capable of developing the image signal of the first color without contacting the photoconductor 1. It is desirable to use a so-called jump developing device in which this is done. In addition, 13 is a polarity converter for aligning the polarity of the toner of each color for development so that the toner adheres easily during transfer, and 14 is a transfer device for charging the transfer material and adsorbing the toner. Charger, 15
1 is a photoconductor cleaner for wiping the surface of the photoconductor 1 after the transfer is completed. (e) Effects of the embodiment Next, the effects will be explained. When the photoconductor 1 is rotated by a drive mechanism (not shown), the photoconductor cleaner 15 causes the photoconductor 1 to rotate.
The surface of the pre-exposure section 2 is then mechanically wiped.
By being exposed to light, the remaining charged portions are erased and electrically wiped away. Subsequently, the photoreceptor 1 is charged to one polarity by the first charger 3. For example, in the case of a photoreceptor having an N-type photoreceptor layer, the surface of the photoreceptor layer is charged to a positive charge and the second to fourth polarities are charged. The result is as shown by curve a in the figure. The steps up to this point are always performed for any combination of colors in Table 1. The following steps vary depending on the color combination selected and will be described separately. () When selecting the first color and the second color: In FIG. 2, following the first charging (curve a), the charging by the second charger 4 (curve b) and the charging by the first exposure section 5 Image exposure of the first color (curve c) takes place simultaneously. Subsequently, the second exposure unit 6 performs second color image exposure (curve d), and the first developer 7 develops the second color image latent image (curve f). Here, once the entire surface is exposed by the entire surface exposure section 11 (curve j), the image latent image of the first color is developed by the third developing device 12 (curve h). After the polarities of the developing color toners are aligned by a polarity converter 13, the two color toners are transferred to a non-transfer material (not shown) while being charged by a transfer charger 14. () When selecting the first color and the third color: In FIG. 3, following the first charging (curve a), the charging by the second charger 4 (curve b) and the charging by the first exposure section 5 Image exposure of the first color (curve c) takes place simultaneously. Subsequently, a third color image is exposed by the third exposure section 6 (curve e), and a third color image latent image is developed by the second developing device 10 (curve g). Once here,
After the entire surface is exposed by the entire surface exposure section 11 (curve j), the third developing device 12 develops the image latent image of the first color (curve h). The steps after the step of aligning the polarity of each color toner are the same as (). () When selecting the second color and the third color: In FIG. 4, charging by the second charger 4 (curve b) is performed following the first charging (curve a). Next, the first developer 7 performs a second color image exposure (curve d), and the first developer develops the second color image latent image (curve f). Here, once the third charger charges the other polarity again (curve i), the third color image is exposed (curve e), and the second developer charges the third color. The color image latent image is developed (curve g). The steps after the step of aligning the polarity of each color toner are the same as (). In the embodiments shown in FIGS. 2 to 4, a laser beam that is modulated and polarized by a scanning optical system (not shown) and then divided into three color signals is used as the light source for exposure. That is, the first laser beam 5A is introduced into the first exposure section 5, the second laser beam 6A is introduced into the second exposure section 6, and the third laser beam 9A is introduced into the third exposure section 9. It's summery. In this way, combination printing of any two colors from the first color to the third color becomes possible. Table 1 summarizes the usage status of devices based on this color combination.

【table】

[Table] Here, ○: used equipment, ×: unused equipment, C1: 1st color image signal C2: 2nd color image signal C3: 3rd color image signal I1: 1st exposure section I2 :Second exposure section I3:Third exposure section D1:First developer D2:Second developer D3:Third developer C03:Third charger PL:Full surface exposure section. (F) Structure of the Invention As described above, the electrophotographic device of the present invention capable of selecting printing colors includes a photosensitive layer formed by sequentially laminating a photoconductive layer and an insulating layer on the surface of a conductive support. The exposure and development device includes a pre-exposure section, a first charger that charges the photoconductor to one polarity, and an exposure and development device provided at a position facing the photoconductor. a second charger for charging the body to the other polarity; a first exposure section having an optical axis passing through a side wall of the second charger and capable of exposing an image signal of a first color; and an image of a second color. a second exposure section capable of exposing a signal; a first developing device capable of developing a second color image signal; a third charger capable of recharging the photoreceptor to the other polarity; and a third color image signal. a second developing unit capable of developing an image signal of the third color; a full exposure unit capable of exposing the entire surface of the photoconductor; and a third developing unit capable of developing an image signal of the first color. A developing device and a polarity converter for aligning the polarity of toner of each color are sequentially provided. (g) Effects of the present invention As explained in detail above, in the present invention, only one photoreceptor is required, so not only can clear multicolor electrophotographs without color shift or color mixture be obtained, but also
It is now possible to select and print two colors out of three colors without any color misalignment.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing the electrophotographic apparatus of the present invention, FIG. 2 is a diagram showing a case where a first color and a second color are used in combination, and FIG. 3 is a diagram showing a case where a combination of a first color and a third color are used. , Figure 4 shows the second and third colors.
It is a graph showing each exposure process in the use of color combinations. 1... Photoreceptor, 2... Pre-exposure section, 3... First
Charger, 4... second charger, 5... first exposure section,
6...Second exposure section, 7...First developer, 8...Third charger, 9...Third exposure section, 10...Second developer, 11...Full surface exposure section, 12... third developer,
13...Polarity converter.

Claims (1)

[Claims] 1 Consists of a photoreceptor having a photosensitive layer formed by successively laminating a photoconductive layer and an insulating layer on the surface of a conductive support, and an exposure and development device provided at a position opposite to this photoreceptor. a pre-exposure section, a first charger that charges the photoreceptor to one polarity, a second charger that charges the photoreceptor to the other polarity, and a second charger that charges the photoreceptor to the other polarity.
a first exposure section having an optical axis passing through the side wall of the charger and capable of exposing an image signal of a first color; a second exposure section capable of exposing an image signal of a second color;
a first developing device capable of developing a color image signal; a third charging device capable of recharging the photoreceptor to the other polarity; a third exposure section capable of exposing a third color image signal; a second developing device capable of developing an image signal of
A third developing device capable of developing an image signal of the first color, and a polarity converter for aligning the polarity of toner of each color for development are sequentially provided.The printing color can be selected. Electrophotographic equipment.