JPS62153968A - Color copying device - Google Patents

Abstract

PURPOSE:To obtain a clear black picture image by obtaining signals of color and black picture in a colored original from an image sensor, exposing a photosensitive body by the signals, and making non-contact reversal developing by color toner. CONSTITUTION:Infrared ray from a colored original 1 is irradiated on an image sensor 7 or a photosensitive body 16. After developing only black image in the colored original of the photosensitive body by a black toner, the photosensitive body is charged again, and color separated visible light from the colored original is irradiated on the image sensor, and signals of color and black image in the colored original are obtained from the image sensor. The photosensitive body is exposed by the signals and non-contact reversal developing is made by color toner. Thereby, the color image and black image in the colored original can be developed separately. Thus, the black image goes to clear instead of being a compound color.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color copying apparatus that can be used in a color copying machine or a color printer.

BACKGROUND OF THE INVENTION Conventionally, in copying machines and laser printers, various methods have been used to appeal to the human visual sense in color rather than black and white monochrome. For example, a monochromatic color image can be obtained by replacing the developing machine with a color toner, or by transferring the monochrome image onto the transfer paper again using a different color toner. , and obtain multicolor superimposed color images. Furthermore, full-color images are also obtained by repeating transfer onto transfer paper multiple times using multiple color toner developing machines in a copying machine.

On the other hand, for laser printers as well, a method of obtaining a two-color printer image has been proposed in order to distinguish characters and dividing lines by color.

Problems that the invention aims to solve Obtaining color images using conventional methods requires time and effort, requires a large machine, consumes a lot of power, and has problems such as black text being unclear due to mixed colors. There are some problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a compact color copying apparatus that consumes less power and produces clear black images in color originals without color mixture.

Measures to Solve the Problem After exposing the charged photoconductor to light and developing only the portion corresponding to the black image in the color document with black toner, the photoconductor is recharged, and the image sensor receives the image from the color document. By irradiating color-separated visible light, obtaining signals of the color and black images in the color document from the image sensor, exposing the photoreceptor to light using these signals, and performing non-contact reversal development with color toner. This solves the problems of the conventional technology that the black image is unclear due to color mixture, consumes a lot of power, and is large.

When an image sensor or photoreceptor sensitive to infrared light is irradiated with infrared light from a color document, the color image portion of the white color document will soon be exposed to the dye of the printing ink.
This infrared light passes through and is reflected by the white paper under the ink, making it impossible for the image sensor or photoreceptor to distinguish between a white background and a color image. On the other hand, since the printing ink in the black image area is carbon black and absorbs infrared light, infrared light is not reflected. Get the statue.

A charged photoconductor is exposed to light using a black image only signal obtained from an image sensor, or a latent image of only a black image on the photoconductor obtained by irradiation with infrared light is developed with black toner to produce a black image. Apply black toner 5 and toner only to the image area.

Next, the photoreceptor is recharged.

When the image sensor is irradiated with the color-separated visible light from the color original, the image sensor obtains a color image and a black image signal of complementary colors to the color-separated visible light in the color original. Based on this signal, the photoreceptor is negatively exposed to match the previously exposed position.

That is, fog light is applied to the surface of the photoreceptor corresponding to a color image and a black image. Since the black image area already has black toner attached to it, the photoreceptor remains charged even after exposure.
The color image portion is neutralized. If you perform non-contact reversal development with color toner, the color toner will adhere only to the color image area.The color image and black image in the color document can be developed separately, so the black image is clear, and the color due to the light source Since the light reflected from the separated color original is read by a highly sensitive image sensor, the power consumption of the light source can be reduced, and since black and color toner are deposited on the photoreceptor surface, there is no need for a special transfer device. F-7 The installation can be made smaller.

Embodiment FIG. 1 shows a color copying apparatus showing an embodiment of the present invention.

A document 1 with black and color characters is moved at a speed in the direction of the arrow using a halogen lamp 2 and a first mirror 3. The third mirror 4 is optically scanned at a speed of V/2.

The filter 6 can be rotated and replaced, and first,
Replace with a filter that transmits infrared light of soon m or more. Infrared light from the original 1 is imaged by a lens 6 and a filter 6 and irradiated onto an image sensor 7. The image sensor 7 is a sensor made of Sl, such as COD.
It is highly sensitive to infrared light of nm or more.

Among the black and color characters in a color original on a white background, the color characters are detected by the image sensor 7 because the pigment in the printing ink transmits infrared light and the white paper beneath the ink reflects the infrared light. becomes unable to distinguish between white and colored text.

On the other hand, in the case of black characters, the pigment in the printing ink absorbs infrared light in the carbon blank, so no infrared light is reflected. Therefore, the color image is erased on the image sensor 7 and only the black image remains.

A signal from the image sensor 7 is input to an optical printer 8 such as a near-infrared semiconductor laser printer or a red light emitting diode play printer, and the photoreceptor 16 charged by the charger 9 is exposed. Black toner is applied to a portion of the photoreceptor 16 corresponding to the black characters of the original using a thermal developing device 1o.

The photoconductor 16 moves in the direction of the arrow, but the Y (yellow)
9M (magenta), C (cyan) developing machine 11.12.1
3 is separated from the photoreceptor 16, so that the Y, M, and C toners do not adhere to the photoreceptor. Further, the cleaning means 14 is also separated from the photoreceptor 16, and the black toner on the photoreceptor 16 is charged again by the charger 9 while remaining attached. Next, the filter 6 is replaced with a blue filter, the document 1 is fully optically scanned to obtain yellow and black image signals from the image sensor 7, and these signals are input to the optical printer 8 to print the previously exposed image. The photoconductor 16 is aligned with the position.
to negative exposure. That is, the surfaces of the photoreceptor 16 corresponding to the yellow image and the black image are exposed. Since black toner has already been adhered to the black image portion, the photoreceptor 16 remains charged even after exposure, and the charge is removed from the yellow image portion.

When this is subjected to non-contact reversal development using the Y developing machine 11, yellow toner adheres to the yellow image portion. At this time, black, M,
C developing machines 10, 12, and 13 are separated from the photoreceptor.

The cleaning means 14 is moved away from the photoreceptor 16, charged again with the black toner and yellow toner still attached to the photoreceptor 16, the filter is replaced with a green filter, and the magenta image area is scanned optically in the same manner. Make sure all the magenta toner is attached. Next, the filter 6 is converted to a red filter, and cyan toner is applied to the cyan image portion. These four color toners are transferred to a transfer paper 17 by a transfer charger 15.
A clear color image with no black text mixed in can be obtained.

FIG. 2 shows a color copying apparatus showing another embodiment of the present invention. A document 21 having all black and color characters is optically scanned in the direction of the arrow by a halogen lamp 22. filter 26
The image sensor lens 23. is replaced with a filter that transmits infrared light of s o o nm or more. The image sensor 26 is moved away from the optical path, and the original 21 is imaged on the surface of the photoreceptor 36 by the lens 24. The photoreceptor 36 is sensitive to infrared light, and based on the same principle as in the previous embodiment, the color latent image is erased and only the black latent image remains on the surface of the photoreceptor 36. This is developed by normal rotation in a heat developing machine 28, and black toner is attached to the black latent image.

Next, the black toner is attached and recharged, the filter 25 is replaced with a blue filter, the lens 23 and the image sensor 26 are inserted into the optical path, the lens 24 is moved out of the optical path, and the original 21 is formed on the image sensor 26.

Yellow and black image signals are obtained from the image sensor 26, and these signals are input to the optical printer 27, and the photoreceptor 36 is negatively exposed to match the previously exposed position. In the same manner as in the previous example, yellow toner is applied only to the yellow image area 1o. Similarly magenta,
After adhering the cyan toner, a charger 32 makes the charging polarity of black, yellow, magenta, and cyan color toners the same, and then a transfer charger 33 transfers the toner onto a transfer paper 37 to form a black image. It has good gradation and resolution, and can produce very clear color images by mixing colors.

Effects of the Invention The image sensor or photoconductor is irradiated with infrared light from a color document, only the black image in the color document on the photoconductor is developed with black toner, and then the photoconductor is recharged and the image sensor is colored. Irradiates color-separated visible light from the original,
By obtaining signals for the color and black images in a color original from an image sensor, exposing the photoreceptor to light using these signals, and performing non-contact reversal development with color toner, the color and black images in the color original can be separated. Since it can be developed separately, the black image is clear without color mixing, and the light source's power consumption can be reduced by 11%, as the reflected light from the color document separated by the light source is read by a high-sensitivity image sensor. Since the black and color toners are combined and deposited on the top, a special transfer device is not required and the device can be made more compact.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic configuration diagrams showing one embodiment of the present invention. 1.21... Original, 2.22... Halogen lamp, 5, 23.24... Lens, 6.
25・°・°°Filter, 26...Image sensor, 8゜2...Optical printer, 1o
~13.28~31...Developer, 16.36.
...°Photoconductor, 14.35゛...Cleaning means. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure/7 Matsuhachi

Claims (3)

[Claims] (1) A means for exposing a charged photoconductor, a means for developing only a portion corresponding to a black image in a color document with black toner, a means for recharging the photoconductor, and a means for developing a portion of the color document that corresponds to a black image; A photoelectric conversion means is irradiated with color-separated visible light, and signals of color and black images in the color original are obtained from the photoelectric conversion means, and the photoreceptor is exposed to light using the signals, and color toner is applied to the photoreceptor. 1. A color copying apparatus comprising means for performing non-contact reversal development. (2) means for developing only a portion corresponding to a black image in a color original with black toner, irradiating a photoelectric conversion means with infrared light from the color original; 2. A color copying apparatus according to claim 1, further comprising means for obtaining a signal of only a black image and exposing a charged photoreceptor to this signal. (3) The scope of claims characterized in that the means for developing only a portion corresponding to a black image in a color document with black toner includes means for exposing a photoreceptor to infrared light from the color document. 2. The color copying apparatus according to item 1.