JPS5811957A - Multicolor developing method for electrostatic recording system - Google Patents

Abstract

PURPOSE:To form a picture which is not fogged by the mixing of the three primary colors by developing the picture successively with developing agents with cyani, magneta and yellow hues respectively. CONSTITUTION:If the values of adsorption starting electrostatic latent potential and defined as cyanine (color C) 3<magenta (color M) 1 < yellow (color Y) 2 in respective developing agents, the higher potential shows the lower adsorption, namely, the developing agent with higher adsorption starting electrostatic latent potential is difficult to be adsorbed to the remaining charge on the surface of an already formed picture. When it is supposed that the quantity of the remaining charge after development is constant, fogging is more reduced by the development in the hue order of C3, M1, T2 at least in comparison with the order of Y2, M1, C3. Consequently, the development in the hue order of C3, M1, Y2 forms the most superior picture of 7 hues in comparison with other hue orders.

Description

[Detailed description of the invention] The present invention uses three primary colors: magenta color (hereinafter referred to as M color);
Electrostatic recording in which developers of yellow (hereinafter referred to as Y color) and cyan color (hereinafter referred to as C color) are developed one by one on electrostatic recording paper to form a multicolor image by subtractive color mixing. This relates to a developing method in the method. The object is to provide a developing method that enables ideal multicolor image formation by mixing three primary colors.

First, I will briefly explain subtractive color mixing using three primary colors. FIG. 1 is an explanatory diagram of subtractive color mixture of three primary colors, and FIG. 2 is an explanatory diagram showing the relationship between wavelength and spectral reflectance of the three primary colors.

Iruma perceives hues such as red and blue because he perceives hues corresponding to the wavelength components of the light that enters his eyes. Now, an image is formed using a coloring material such as a toner of M color and hue 1 shown in FIG. 1, and then the same #! Suppose that we have formed a degree image. In this case, the image of M color 1 is 400 to 500 of the incident white color.
Although light in the wavelength range of nm and 600 to 700 am is reflected, light in the wavelength range of 500 to 600 nm is absorbed and not reflected. On the other hand, Y color 2 reflects light in the wavelength range of 500 to 700 nm and absorbs light in the wavelength range of 400 to 500 nm. Therefore, only light in the wavelength range of 600 to 700 am is reflected from the overlapping portion of the M color 1 image and the 1 color 2 image and enters the eye. 600-700
Since the color sense corresponding to the nm wavelength range is red, the overlapped portion of M color 1 and 1 color 2 is perceived as red 4 by the eye. Similarly, if you overlap color 1 2 and color 0 3, green P3 5. If you overlap color 3 and M color 1, you will get blue 6, M color 1 and Y color 2
If you stack the three colors 0 and 3, you get black 7.

Therefore, it is possible to form an image of heptadonic hues by using the primary colors and mixed colors of the coloring materials as described above.

Next, the process of image formation using the electrostatic recording method will be briefly explained. Although FIG. 3 shows two layers of image recording information and three layers of general electrostatic recording, 2MI1m will be explained as an example. In the two-layer electrostatic recording paper 8 (hereinafter referred to as recording paper), an insulating layer 8 is provided on the surface of the paper that is the base material, and the paper that is the base material is impregnated with a conductive substance to form the conductive layer 8b. ing. Figure 3(a)
As shown in the figure, when the multi-needle electrode 9 is brought into contact with the surface of the insulating layer 8 and a voltage is applied between it and the conductive layer 8b, the insulating layer 811
This electric charge is generated.

Generally, the multi-needle electrodes 9 are insulated from each other and arranged in a line in the width direction of the recording paper 8.

An electrostatic latent image is formed on the insulating layer 8a of the recording paper 8 by selectively applying a pulse voltage to the multi-needle electrode 9 according to image recording information while moving the recording paper 8 in the direction of the arrow X. The charges constituting the electrostatic latent image can be either positive or negative depending on the polarity of the applied voltage, but it is generally said that generating a negative charge is more reliable because it causes fewer so-called missing spots. The charges forming the silent TM image will be explained below as negative charges. The recording paper 8 on which the electrostatic latent image is formed is developed by the +0 developing device 1 as shown in FIG. 3(b). There are two types of development methods: wet and dry, but both use toner 10, which is colored particles charged with the opposite polarity to the electrostatic latent image. The toner 10d is heated etc. in the fixing device 11 consisting of
By firmly fixing the contained resin to the recording paper 8, the image forming process for one hue is completed. In the case of multicolor development, the above image forming process is repeated for the number of hues. In this case, during the above development, 5. Charge of electrostatic latent image and toner 10. If the oil charges have opposite polarities and the same amount of charge, and both charges are neutralized during development, there will be no residual charge on the image surface formed at the end of the image forming process for one hue, and other charges will be left behind. There is no problem with the image formation process with the hue of .

Therefore, if this amount of residual charge is large, when developing with the second toner 10, the second toner 1 will also be applied to the first image forming area where the second electrostatic latent image does not exist.
0. is electrostatically attracted, resulting in color mixing. Therefore, for example, in the case of image formation using the hue of M color 1 at the first time and the hue of Y color 2 at the second time, ideally M color 1. Y color 2. It should be possible to obtain an image of the three hues of red 4 by mixing the colors with Y, but all of M color 1 is mixed with Y color 2 to become red 4, making it impossible to obtain an image of M color 1. The present invention was made in view of the above circumstances, and uses 1% of toner of three primary colors.
The present invention provides a developing method that prevents color mixing that differs from image information, so-called 6 colors, and obtains images with 7 different hues.

Hereinafter, one factor that causes residual charges to occur on images after development will be explained.

The reason for this is that the amount of charge on both the recording paper 8 and the developer varies widely depending on the environmental conditions even if they are charged under constant conditions. This means that even if the electrostatic latent image and the charges on the image agent are adjusted to maintain a balance under a certain environment, the above balance will no longer be maintained due to changes in the environment. Since the base paper is porous and easily absorbs moisture, the volume resistivity of the insulating layer 8a constituting the recording paper 8 is 1G' depending on environmental conditions such as humidity, temperature, and atmospheric pressure.
.

~1017ρcIrL1! ◇Since the insulating layer 8a has a function similar to a dielectric in a type of capacitor, the amount of charged charge also changes approximately 60*1ijl in response to the above-mentioned change in volume resistivity! ◎On the other hand, for the three primary color developers, static charge is generally given to the developer due to friction, etc., but the amount of charge changes due to the flow process due to changes over time and pump equalization, and the amount of charge changes approximately P7 4 There is an increase or decrease of 〇-. As described above, since the charge amount of both the recording paper 8 and the developer varies widely, this poses a major problem. The present invention focuses on the fact that the charging characteristics of the three primary color developers and the minimum voltage that starts electrostatic adsorption to the electrostatic latent image are different, and multicolor development is performed by the development order according to the above-mentioned physical properties of the developer. As a result, a 7-color image without fogging and in accordance with the image information is obtained. First, let us consider the fog caused by the next developer on the image forming area.

When the surface potential due to the electrostatic latent image charge on the recording paper 8 is constant, M color 1. Y color 2. Assuming that the order of the magnitude of the surface potential of the image area due to the residual charge in the image area after 1tca of each developer of C color 3 is deposited is 0 color 3 < M color 1 < Y color 2.
The smaller the absolute value of the surface potential due to residual charge in an image area, the more difficult it is for the next developer to be electrostatically attracted to that area.

Therefore, if we focus only on the residual charge in the image area, the developer has 0 colors and 3. If the colors are developed in the order of hues of M color 1 and Y color 2, fogging will be minimized. Next, the potential of the electrostatic latent image at which each developer starts adhering to the electrostatic latent image will be considered.

Now, if the order of the values of the adsorption start electrostatic latent image potential for each developer is 0 color 3 < M color 1 < Y color 2, the developer with a higher adsorption start electrostatic latent image potential is difficult to adsorb, in other words. If this is done, the residual charge on the image forming surface that has already been formed will be less likely to be adsorbed, so assuming that the amount of residual charge after development is constant, the developer will be applied in the order of hues: 0 color 3, M color 1, Y color 2. It is more advantageous to prevent fog when developing at least in the order of Y color 2, M color 1.0 color 3. Focusing on the difference in the starting electrostatic latent image potential, we conducted an experiment to find that developing in the order of 0 color 3, M color 1% Y color 2 was the best compared to developing in other orders. An image with seven hues was obtained. The development order of the developer and the obtained color words are shown in $1 from the experiment. The x mark indicates a case where the hue is completely different from the theoretical hue. 0. As mentioned above, in item 5, the development order is 0 color. 3.
M color 1. The theoretical seven hues are obtained only when Y color 2 is used. An example of the prelude to the above experimental example is described below.

When the voltage applied to the recording paper 8 is 600 V, the surface potential of the electrostatic latent image generated by the above applied voltage is 40 to 100 V, and the potential of the three primary color developers is 8 to 15 V, the residual charge of each developer immediately after development Surface potential of image plane C Color 3 Ha
15V, M color 11;! e23V, Y color 2i:! e3
It was 2V. Note that there is a method to remove the residual charge on the image forming surface using a static eliminator such as a corona discharge, but it is extremely difficult to reduce it to zero, and the static eliminator may even induce charging, so it is not a stable effect. I can't do it. As described above, according to the multicolor development method according to the present invention, an image with seven hues according to the image information can be obtained without removing the residual charge after development, so the practical effect is extremely large.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of subtractive color mixture of three primary colors, Figure 2 is an explanatory diagram showing the relationship between the wavelength of the three primary colors and spectral reflectance, and Figure 3 is an explanatory diagram of the image forming process of a general electrostatic recording method. . 0 8 - Electrostatic recording paper, coins...Developer, 10th revision... Toner Fil-111... Fixer. Patent applicant Atsushi Doi Representative of Toyo Denki Seizo Co., Ltd. Japanese Patent Application Publication No. 1983-11957 (4) Figure 2 Figure 9r

Claims (1)

[Claims] The recording medium is electrostatic recording paper, and at least magenta. In an electrostatic recording method in which developers of yellow and cyan hues are developed multiple times 111 [f times, the development is performed in the order of cyan, magenta, and yellow developers. Multicolor development method.