JPS6370271A - Full-color electrophotographic method - Google Patents

Abstract

PURPOSE:To improve the reproducibility of green and to obtain a full-color image of high quality by setting the L, C, and H deg. of yellow, magenta, and cyan within prescribed ranges. CONSTITUTION:The colors of toner particles are specified for a full-color electrophotographic method which obtains a full-color image by stacking toner layers of three colors, i.e. yellow, magenta, and cyan. Namely, when the real specific gravity of toner is 1.0, the toner is stuck on a transparent 'Mylar<g>' film to 1.0mg/cm<2> and fixed so that the glossiness is >=30%. The chromaticity is measured on an MgCO3 standard plate with 98% reflectivity from the back of a sample and converted to LCH deg.. The chromaticity ranges of yellow, magenta, and cyan on a 10mum film in the LCH deg. system are so set that L>=80>=, C>=80, 100 deg.<=H deg.<=110 deg.; L>=40, C>=68, 345 deg.<=H deg., and L>=40, C>=50, 240 deg.<=H deg.<=225 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a color electrophotographic method using an analog full-color precopy.

[Prior art] Conventional technologies include color efficiency (EFF) and color purity (GRA).
It has been thought that the color tone of an image can be improved by the color characteristic of hue error (HUE), and there has been a trend toward improving color efficiency and making colors closer to ideal colors.

Ordinary process ink for printing is yellow, C≦85, H°ki 100°magenta, C
≦67, H' = F15° cyan, and 260° set ink in Cs2O, H' is used.

Current toner for full-color copying uses colorants for printing ink horizontally developed, but in analog full-color copying, unlike printed matter, image 9A processing such as masking and tJcR is not performed. If three types of toner, yellow, magenta, and cyan, having L2, a″l, b)! similar to printing ink are used, the reproducibility of green in particular is poor, resulting in images of low quality.

[Purpose] In order to improve the above-mentioned drawbacks of the prior art, the present invention improves the reproducibility of green by defining the ranges of L', C, and H'' for yellow, magenta, and cyan. The purpose is to obtain a full color image.

[Configuration] The groove configuration of the present invention to achieve the above object is yellow,
In a full-color electrophotographic method that obtains a full-color image by overlapping magenta and cyan toner layers, the range of chromaticity of a 10 μm film of yellow toner is
In the LCH' color system, the range of chromaticity of the 10 μm film for yellow toner and magenta toner is L, which is within the range of L'' ≧801C≧80.100°≦H°≦110°.
In the color system of CH', L*≧40. CaB6.345°≦H'<: 35
The chromaticity range of 10 μm film for magenta toner and cyan toner is within the range of 5°.
In the color system of CH', L*≧40. This is a full-color electrophotographic method that uses a combination of three types of toner: C≧40.240°≦H°≦255°.

In the present invention, we have developed a method for measuring the chromaticity of toner.
Since there is no method determined by S etc., we have set up our own method.

Since the toner must have strong coloring power and relatively good transparency, the chromaticity changes depending on the layer thickness. For this reason, even if the color of toner solidified into a thick pellet is measured, the color will be significantly different from the actual color on the image.

For this reason, it is desirable to measure the color when the toner layer thickness is about 10 μm, which is close to the toner thickness on the actual image. However, since it is quite difficult to produce a 10 μm film using toner alone, the color of the toner was measured by the following method.

Toner color measurement method in the present invention On a transparent Mylar film (100 μm) support,
If the true specific gravity of the toner is 1.0, the amount of toner is 1.0mg/
cm', and as it is, it is sufficiently fixed to have a gloss level of 30% or more. Using this as a sample, apply a MgC0+ standard plate with a reflectance of 98% from the Mylar film surface, that is, the back side of the toner layer, and measure the chromaticity (L East a) Ib frequency of the sample using a colorimeter or spectral reflectance meter. ) was measured, and this L'a'b was converted to LCHo.

Conversion formula % formula %] However, aH=○ b*≧O-H' = 90'a'=ob'<Q-+H' = 270' The measurement conditions are JIS 8722-1982 4.3.1 According to condition 4 of °.

Also, trap the reflected light.

In order to produce a yellow toner having a chromaticity range according to the present invention, for example, C, I as a coloring agent may be used.

A yellow colorant that exhibits a clear greenish yellow color, such as Plugment Yellow 17, may be used.

Further, in order to obtain a magenta toner having a chromaticity within the range of the present invention, for example, C,1, Pigment
A magenta coloring material such as Red 81 that exhibits a clear bluish red color may be used.

Further, in order to obtain a cyan toner having a chromaticity within the range of the present invention, for example, C and I can be used as colorants.

A cyan colorant that exhibits a clear greenish yellow color, such as 5olvent Blue 25, may be used. Also, C,
1, Pigment 25 and other commonly used cyan colorants, C, 1, Pigment Green
Phthalocyanine green such as n 36 and C, 1, pi
A metal-free phthalocyanine blue such as gmentBlue 16 may be mixed.

Further, in order to obtain a toner having a chromaticity within the range of the present invention, an optically nearly transparent resin such as a styrene-acrylate resin or a polyester resin may be used as the binder resin.

Hereinafter, the present invention will be specifically explained with reference to Examples.

A total of nine types of toners, three types each for each color of yellow, magenta, and cyan shown in Table 1 below, were prepared using a common method for producing Example toners.

The chromaticity (L*aW) of 10μm film of these toners
b*) and LC)-1 are shown in Table 1.

Table 1 Y: Yellow toner M: Magenta toner C: Cyan toner To outline the method for manufacturing a developer using the above coloring material, first, 5 parts by weight of colored number and polyester resin ( Atrac-382A, Kao) ioo parts by weight are dry mixed, cooled, pulverized in a hammer mill, further finely pulverized in a jet mill, and the finely pulverized product is separated to form a toner with an average volume particle size of 11 μm. And so.

This toner is mixed with an amorphous redox iron standard (TEFV250 ~
400 mech (Nippon Tetsuko Co., Ltd.) was prepared to have a toner concentration of 5 wt %, and used as a developer.

An image was formed using a full color copying machine (Ricoh Color 5000) using a combination of three types of toners listed in Table 1: yellow, magenta, and cyan to obtain a full color image. At this time, we used Kodak's gray scale and color patch as the original, and in the full color copy image, we adjusted the gray scale so that it was reproduced as faithfully as possible (gray looks like gray), and also added yellow (Y), magenta (
The densities were adjusted so that the highest densities (copies of the black portion) of each monochrome copy of M) and cyan (C) were Y≧0.8, M≧1.2, and C≧1.4.

Glue Cocolorer 5000 (hereinafter referred to as RC-500) in the above condition
0) and 2 for each color of Y, M, and C.
Output an image in color superimposition mode (Y+M, Y+C, M+C). At this time, the chromaticity (L 91 a MA b14
) are shown in Table 2.

However, paper (TYP E 1000 manufactured by Suko Co., Ltd.)
A paper original with a whiteness of 88% or higher was used, and fixing was carried out at a temperature at which hot offset did not occur and the toner layer was sufficiently melted and colored.

Table 2 As can be seen from the results in Table 2 above, toner combination 1 of the present invention! (Y-I, M-I, C-I>), the overlapping portion of YMC [Y + M, Y +
C, M + C → R (red), G (green), B
(Blue)], it is clear that a colorful (high Chroma) color can be produced. Furthermore, it is easy to create gray by combining three colors.

Also, in this state (with the optimal color adjustment method) Y-I~
When each image was copied using 27 combinations of three types of developers: M, M-I to ■, and C■ to ■, the toner of the present invention had the best reproducibility. (MC color reproducibility is good) 19 good copy images were produced that were close to the original.

Furthermore, the resin which is one component of the above-mentioned toner of the present invention is changed from polyester to styrene-n BMA copolymer (SBM-7).
The same results were obtained even if the material was replaced with 3 Sanyo Chemical Co., Ltd.).

[Effects] As explained above, by employing the toner combination of the present invention in an electrophotographic method in which toner layers of at least three colors of Y, M, and C are superimposed to form a full-color image, other colors can be produced. In particular, the color reproducibility of secondary (R, G, B) can be improved without impairing the color reproducibility and gray balance.

Furthermore, the reproducibility of painterly manuscripts and photographic manuscripts is dramatically improved, and high-quality copy images can be obtained.

Claims (1)

[Claims] In a full-color electrophotographic method for obtaining a full-color image by superimposing three-color toner layers of yellow, magenta, and cyan, the range of chromaticity of a 10 μm film of yellow toner is as follows:
The range of chromaticity of the 10 μm film for yellow toner and magenta toner is L, which is within the range of L*≧80, C≧80, 100°≦H°≦110° in the LCH° color system.
In the CH° color system, the range of chromaticity of a 10 μm film for magenta toner and cyan toner is L*≧40, C≧68, 345°≦H°≦355°.
A full-color electrophotographic method characterized by using a combination of three types of toner: a cyan toner within the range of L*≧40, C≧40, and 240°≦H°≦255° in the CH° color system. .