JPH04337736A - Image receiving paper for electrophotographic transfer - Google Patents

Abstract

PURPOSE:To provide image receiving paper for electrophotographic transfer having excellent color tone reproducibility of an original plate by especially improving the color tone of image receiving paper for electrophotographic transfer used for a copying machine, a printer, facsimile, etc., utilizing an electrophotographic system. CONSTITUTION:The surface reflecting characteristics of this image receiving paper for electrophotographic transfer expressed by a method stipulated by JIS Z8730 are L*>=90, +4>=a*>=-2 and +2>=b*>=-9. This image receiving paper is obtd., e.g. by impregnating or applying a coating soln. contg. a fluorescent white dye.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an image receiving paper for electrophotographic transfer used in an electrophotographic copying machine. It is related to.

0002

[Prior Art] Electrophotographic copying machines, printers, facsimile machines, etc. form a charge image on the surface of a photosensitive drum or photosensitive belt containing selenium, amorphous silicon, organic semiconductor, etc. Toner particles are attached to the charged image to form a visible image by developing with charged toner particles (positive type) or reversal development with toner particles of the same polarity (negative type), and then the image receiving paper is By contacting this photosensitive surface and performing a corona discharge treatment from the back side of the paper, a visible image is transferred to image-receiving paper and further fixed by heat, light, pressure, etc. to obtain a printed image.

[0003] In recent years, with the progress of office automation, various functions of copying machines, printers, and facsimile machines that utilize electrophotography have been improved, and efforts are being made to increase added value. For example, in copying machines, improvements have been made not only in mechanical configuration functions such as higher speeds, scaling, trimming, automatic double-sided copying, and automatic document feeding, but also in improvements in exposure methods, toner quality, and development methods. , multi-color transfer, full-color transfer, and other quality improvements have been made, progressing from simple monochrome transfer to multicolor transfer.

[0004] On the other hand, recent electrophotographic copying machines are designed to be able to use plain paper to coated paper as image-receiving paper, and are not selective about the image-receiving paper. However, with the shift to color copying machines, when original images are transferred to conventional image-receiving paper, the tones of the image, especially intermediate tones, are affected by the hue of the image-receiving paper and are not reproduced satisfactorily. is the current situation.

[0005]

[Problems to be Solved by the Invention] The present invention relates to image receiving paper for electrophotographic transfer used in copying machines, printers, facsimile machines, etc. that utilize electrophotography, and in particular, it is an object of the present invention to improve the color of the original by improving the color tone of the image receiving paper. An object of the present invention is to provide an image receiving paper for electrophotographic transfer that has excellent color tone reproducibility.

[0006]

[Means for Solving the Problems] The present invention provides surface reflection characteristics of image receiving paper (display method specified in JIS Z 8730) such that L*≧90, a*=+4 to -2, b*=+2 to - An image-receiving paper for electrophotographic transfer, characterized in that:

[0007]

[Operation] The reproducibility of the image on the original plate on the receiving paper is
As mentioned above, the color tone of the image on the original plate is affected by the color tone of the image receiving paper, but it is also true that the color tone of the image on the original plate can vary considerably depending on the degree of fluorescence. Therefore, the method for measuring the surface reflection characteristics of receiver paper is as follows:
Generally, JIS Z 8722 (method for measuring object color in a two-degree visual field) is well known, but it is not applicable to objects with fluorescence. However, when looking at images obtained by electrophotography, we have found that it is extremely important to evaluate the hue with fluorescence taken into account in order to accurately express the substance of the color tone.

[0008] The inventors of the present invention have developed the following methods as specified in JIS Z 8730 [L* (Elster), a* (Aster), b
*(B-Star)] In accordance with the Display Law, as a result of extensive research into image-receiving paper to accurately reproduce the image on the original plate in a state that contains fluorescent light, the surface reflection characteristics of image-receiving paper (J
The display method specified in IS Z 8730) is L*≧9
It has been found that adjustment to a range of 0, a*=+4 to -2, and b*=+2 to -9 is the most excellent in reproducing the color tone of the original plate.

[0009] L* represents lightness; the larger the value, the whiter it is;
The smaller the value, the darker the color. a* represents redness,
The larger the value, the stronger the redness, and (-) the stronger the greenness. b* represents yellowness; the larger the value, the stronger the yellowness; and (-), the stronger the blueness. Generally, the color tone is expressed by the position of a graph with a* on the horizontal axis and b* on the vertical axis. When both a* and b* are 0, the color is expressed as colorless.

Incidentally, if L* is smaller than 90, the copied image will appear darker than the original. If a* is greater than 4, the copied image will be more reddish than the original, and if it is less than -2, the copied image will be too greenish. When b* is 2 or more, the yellowish tinge is too strong, and when it is less than -9, the bluish tinge is too strong, and in either case, the reproduction of the tone of the original plate is not sufficient. In order to achieve better results within this range, preferably L*≧9
3, a*=+3 to -1, b*=±0 to -8, more preferably L*≧93, a*=+3 to ±0, b*=-2 to -7
It is desirable to adjust to . In order to achieve this value, it is more preferable that the image-receiving paper is impregnated or coated with a fluorescent white dye.

As the fluorescent white dye used in the present invention, diaminostilbendisulfonic acid derivatives, imidazole derivatives, maculin derivatives, etc. are appropriately used. The pulp fibers constituting the image-receiving paper are not particularly limited in terms of their manufacturing method or type; for example, KP, SP,
Chemical pulp such as softwood pulp and hardwood pulp obtained by AP method etc., SCP, other BCTMP, CTMP
, CGP, RGP, SGP, TMP, etc., waste paper pulp such as DIP, non-wood pulp such as hemp pulp, synthetic pulp, and various synthetic fibers or glass fibers are used in appropriate combinations. Fillers for forming the image-receiving paper include those commonly known and used in the art, such as talc, kaolin, clay, calcined kaolin, calcium carbonate, aluminum hydroxide, titanium dioxide, magnesium silicate, magnesium sulfate, and aluminosilicate. , mineral fillers such as silica and bentonite, polystyrene resin fine particles, urea-formalin resin fine particles, thermally expandable fine hollow particles, non-thermal expandable fine hollow particles, and other organic fillers are used as appropriate. Of course, in addition to these, the pulp slurry also contains sizing agents such as rosin size, petroleum size, alkyl ketene dimer size, alkenyl succinic anhydride size, and stearic anhydride size, as well as anionic, cationic, and nonionic sizing agents. or amphoteric polyacrylamide polymer,
Improving the yield of organic compounds such as polyethyleneimine and its derivatives, polyamine, polyamide, polyamine and its derivatives, polyethylene oxide, vegetable gum, polyvinyl alcohol, cationic latex, cationic urea formalin resin, melamine melamine formalin resin, polyamide resin, etc. agents, drainage improvers, paper strength enhancers, dyes,
A pH adjuster, a pitch control agent, a slime control agent, an antifoaming agent, an antistatic agent, etc. can be added as appropriate.

The paper machine is not particularly limited, and a Fourdrinier paper machine, a twin wire paper machine, a short wire paper machine, a circular wire paper machine, a Yankee paper machine, etc. can be used as appropriate. The image-receiving paper for electrophotographic transfer of the present invention can obtain even better effects when coated with a coating liquid within a range that satisfies the above-mentioned surface reflection characteristics. Regarding the composition of the coating liquid, the pigments used in combination include various pigments commonly used in general coated paper, such as talc, kaolin, delamic kaolin, clay, calcined kaolin, satin white, calcium carbonate,
Mineral fillers such as aluminum hydroxide, titanium dioxide, magnesium silicate, magnesium sulfate, aluminosilicate, silica, bentonite, white carbon, colloidal silica, sericite, polystyrene resin particles, urea-formalin resin particles, thermally expandable micro hollow particles , non-thermally expandable micro hollow particles, and other organic fillers are used as appropriate.

The binder resin is a water-soluble resin and/or a water-dispersible resin, such as starch, oxidized starch,
Starches such as enzyme-modified starch, cationized starch, thermochemically modified starch, amphoteric starch, and esterified starch; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; proteins such as casein, gelatin, soybean protein, and synthetic protein; Polyvinyl alcohol such as incompletely saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, carboxy-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol, cationic polyvinyl alcohol, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic ester Acrylic copolymer latex such as copolymer,
Vinyl polymer latex such as ethylene-vinyl acetate copolymer, alkali-soluble or alkali-insoluble polymer latex modified with carboxyl groups, etc., and one type of melamine resin, etc. Two or more types are selected and used as appropriate. Generally, the binder resin is blended in an amount of about 8 to 200 parts by weight per 100 parts by weight of the pigment. In addition, depending on the application, the coating liquid may contain various cationic, anionic, nonionic, and Amphoteric surface sizing agent, conductive treatment agent, antifoaming agent, colorant, fluorescent white dye, ultraviolet inhibitor, antistatic agent, lubricant, dispersant, plasticizer, pH adjuster, mold release agent, flow modifier,
Various auxiliary agents such as a solidification accelerator, a waterproofing agent, and a sizing agent are appropriately blended as additives as necessary.

[0014] The coating equipment is not particularly limited, and may include a two-roll or metering blade type size press, a gravure coater, a gate roll, a bill blade and short dwell coater, an air knife coater, a bar coater, and a curtain. Conventional coating equipment such as a coater, die slot coater, brush coater, Champlex coater, etc. can be used appropriately. In this case, the appropriate amount of coating on one side is 1 to 5 g/m2. 5g/m2
If this is the case, it will be far removed from plain paper.

[0015]

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is of course not limited to these. Note that "parts" and "%" in the examples indicate "parts by weight" and "% by weight", respectively, unless otherwise specified. Regarding the image receiving paper obtained in the example, the whiteness and surface reflection characteristics were measured,
Furthermore, CANON COLOR LASER COPIE
R 500 was used, and the original version was Electrophotography Society Test Chart, No. Transfer images were obtained using 5-1 and 5-2, and each was evaluated.

Example 1 35 parts of NBKP of freeness 450cc and LBKP6
To 5 parts of pulp slurry having a whiteness of 86.2%, 15 parts of talc, 1.4 parts of rosin size, and 3 parts of sulfate were added to 100 parts of pulp. This pulp slurry
Paper is made using a Fourdrinier multi-tube cylinder dryer paper machine, and then oxidized starch (product name: Ace A, manufactured by Oji Cornstarch) and fluorescent white dye (product name: BSU-PN, manufactured by Bayer) are mixed at a ratio of 1:0.75. The coating solution prepared as follows was coated and dried using a size press to give a dry weight of 3 g/m2, thereby obtaining an image receiving paper having a basis weight of 85 g/m2. The evaluation results were as shown in Table 1.

Example 2 35 parts of NBKP of freeness 450cc and LBKP6
5 parts of pulp slurry with whiteness of 82%, 10 parts of pulp
To 0 parts, 15 parts of talc, 1.4 parts of rosin size, and 3 parts of sulfate were added. This pulp slurry is made into paper using a Fourdrinier multi-tube cylinder dryer paper machine, and then oxidized starch is made into paper using a size press machine with a dry weight of 1.5 g/m2.
After coating and drying, use a short dwell coater to apply a coating liquid consisting of 70 parts of kaolin, 30 parts of light calcium carbonate, 3 parts of oxidized starch, 14 parts of SBR latex, 2 parts of fluorescent white dye, and 1 part of polyvinyl alcohol. was coated on both sides to a dry weight of 4 g/m2 and dried to obtain an image receiving paper with a basis weight of 85 g/m2. The evaluation results were as shown in Table 1.

Example 3 35 parts of NBKP of freeness 450cc and LBKP6
5 parts of pulp slurry with whiteness of 87%, 10 parts of pulp
For 0 parts, the dye methyl violet (KFT-VPR
) 2 x 10-4 parts, talc 15 parts, rosin size 1.4
1 part, and 3 parts of sulfate were added. This pulp slurry is made into paper using a Fourdrinier multi-tube cylinder dryer paper machine, and then oxidized starch is processed into paper using a size press machine at a dry weight of 1.5 g/
It was coated and dried to give an image receiving paper with a basis weight of 85 g/m2. The evaluation results were as shown in Table 1.

Example 4 35 parts of NBKP of freeness 450cc and LBKP6
5 parts of pulp slurry with whiteness of 82%, 10 parts of pulp
For 0 parts, dye BLUE (SST-BG) 2 x 10-
5 parts of talc, 1.4 parts of rosin size, and 3 parts of sulfate were added. This pulp slurry was made into paper using a fourdrinier cylinder dryer paper machine, and then oxidized starch was coated and dried using a size press to give a dry weight of 1.5 g/m2 to obtain an image receiving paper with a basis weight of 85 g/m2. Ta. The evaluation results were as shown in Table 1.

Comparative Example 1 10 parts of NBKP of freeness 450cc and LBKP4
Whiteness: 75, consisting of 0 parts and 50 parts of recycled newspaper pulp
% pulp slurry, per 100 parts of pulp, 8 parts of calcium carbonate, and 0.
0.07 parts of cationic starch, 0.5 parts of cationic starch, and 0.02 parts of retention aid were added. This pulp slurry was made into paper using a fourdrinier cylinder dryer paper machine, and then oxidized starch was coated and dried using a size press to give a dry weight of 1.5 g/m2 to obtain an image receiving paper with a basis weight of 85 g/m2. Ta. The evaluation results were as shown in Table 1.

Comparative Example 2 35 parts of NBKP with 450 cc of freeness and 6 parts of LBKP
5 parts of pulp slurry with whiteness of 72%, 10 parts of pulp
For 0 parts, dye BLUE (SST-BG) 1 x 10-
3 copies, YELLOW (DFY-BC) 1 x 10-3 copies,
15 parts of talc, 1.4 parts of rosin size, and 3 parts of sulfuric acid were added. This pulp slurry was made into paper using a fourdrinier cylinder dryer paper machine, and then oxidized starch was applied and dried using a size press to give a dry weight of 1.5 g/m2 to obtain image receiving paper with a basis weight of 85 g/m2. Ta. The evaluation results were as shown in Table 1.

Comparative Example 3 35 parts of NBKP with 450 cc of freeness and 6 parts of LBKP
5 parts of pulp slurry with whiteness of 72%, 10 parts of pulp
Dye RED (LRF-3B) 2x10-3 for 0 parts
15 parts of talc, 1.4 parts of rosin size, and 3 parts of sulfate were added. This pulp slurry was made into paper using a fourdrinier cylinder dryer paper machine, and then oxidized starch was coated and dried using a size press to give a dry weight of 1.5 g/m2 to obtain image receiving paper with a basis weight of 85 g/m2. Ta. The evaluation results were as shown in Table 1.

Comparative Example 4 35 parts of NBKP with 450 cc of freeness and 6 parts of LBKP
5 parts of pulp slurry with whiteness of 72%, 10 parts of pulp
For 0 parts, dye YELLOW (BFY-5G) 2x1
0-3 parts, 15 parts of talc, 1.4 parts of rosin size, and 3 parts of sulfuric acid were added. This pulp slurry was made into paper using a fourdrinier cylinder dryer paper machine, and then oxidized starch was applied and dried using a size press to give a dry weight of 1.5 g/m2 to obtain image receiving paper with a basis weight of 85 g/m2. Ta. The evaluation results were as shown in Table 1.

Comparative Example 5 35 parts of NBKP with 450 cc of freeness and 6 parts of LBKP
5 parts of pulp slurry with whiteness of 72%, 10 parts of pulp
For 0 parts, dye BLUE (SST-BG) 2x10-
3 parts, 15 parts of talc, 1.4 parts of rosin size, and 3 parts of sulfuric acid band were added. This pulp slurry was made into paper using a fourdrinier cylinder dryer paper machine, and then oxidized starch was applied and dried using a size press to give a dry weight of 1.5 g/m2 to obtain image receiving paper with a basis weight of 85 g/m2. Ta. The evaluation results were as shown in Table 1.

[0025]

[Table 1]

The whiteness and surface reflection characteristics of the obtained image-receiving paper were measured by the following method. 1) Measurement of whiteness; In accordance with JIS P 8123, it was expressed as reflectance % measured with a Hunter reflectance meter using a blue filter (457 nm). 2) Surface reflection characteristics (L*, a*, b*); Macbet
h These are numerical values measured using COLOR-EYE. (Including xenon light source, CIE-Lab display, and fluorescence) 3
) Appearance evaluation of transferred image: The difference in color tone between the transferred image and the image on the original plate was visually evaluated. ◎: The color tone is very similar to the original. ○: There is a slight difference in color tone from the original. ×: There is a considerable difference in color tone from the original.

[0027]

[Effects of the Invention] As shown in the table, it is clear that the image receiving paper for electrophotographic transfer of the present invention is an image receiving paper with excellent reproducibility of the color tone of the original plate.

Claims (2)

[Claims] Claim 1: Surface reflection characteristics of image receiving paper (JIS Z 87
30) is L*≧90, a*=+4
-2, b*=+2 to -9, an image receiving paper for electrophotographic transfer. 2. The image-receiving paper for electrophotographic transfer according to claim 1, wherein the image-receiving paper is impregnated with or coated with a water-soluble fluorescent white dye.