JPS62198875A - Transfer paper for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a copy having high image quality without overlap feeding and paper jam in the stage of paper feeding by providing an image receiving layer having <=2.0mum center line average height on the surface to at least one face of base paper and adjusting the standard deviation of the coefft. of static friction between the sheets of the paper in the stacked state to <=0.05. CONSTITUTION:Transfer paper for electrophotography is obtd. by applying a coating compd. which consists essentially of a pigment having low adhesiveness and adhesiveness to at least one face of the base paper and is compounded with an antisticking agent at need to at least one face of the base paper and adjusting the standard deviation of the coefft. of static friction between the sheets of the paper to <=0.05. A smoothing treatment is executed by passing the paper many times between the nip of a rigid roll and elastic roll of a super calender or gross calender. The smoothing treatment is so adjusted that the center line average height of the surface attains <=2.0mum, more preferably <=1.5mum in order to obtain the substantial image surface gloss. The copy having high image quality is thus obtd. without the overlap feeding and paper jam during paper feeding with an electrophotographic copying machine.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to electrophotographic transfer paper, and is particularly useful for high-quality copies in monochrome and color electrophotographic copying machines that reproduce image quality comparable to photographs and printing. The present invention relates to an electrophotographic transfer paper suitable for obtaining.

[Prior Art] Coated papers such as art paper and coated paper are used in elaborate printing and multicolor printing, where planar offset printing is the mainstream. This is because the coated paper has a smooth surface, which allows for good contact with the ink film during printing, resulting in faithful reproduction of images, high gloss, and good color reproduction.

Regarding the suitability of coated paper for electrophotography, there is a study by Tsukatani et al. They argue that coated paper is physically smooth and adheres uniformly to the photoreceptor, so theoretically it should be possible to obtain a clean toner transfer image, but they have not actually applied it to existing equipment. In some cases, the image becomes rough (Tsukatani, Ota:
Non-impact printer paper, paper pulp technology times,
27° No. 4 (1984) 31-36>. In fact, there is no advantage in image quality when using coated printing paper for electrophotography.
is hardly used.

Studies conducted by the present inventors have revealed that smooth coated paper for printing causes double feeding and paper jams during paper feeding in electrophotographic copying machines. It has been confirmed that this problem occurs frequently regardless of the paper feeding method, such as the feed roll/corner snapper type or the feed roll/retard type. It has been found that the cause of this is that the coefficient of static friction between coated printing papers in a stacked state is much larger than that of plain paper. This is because the coated paper is smooth, so the contact between the papers is too good, and
This is due to the characteristics of the paint binder and pigment present on the surface.

On the other hand, regarding methods for improving image quality in electrophotography, Tsukatani et al. suggest reducing the toner particle size and thinning the transferred toner layer in comparison with the printing process (Tsukatani et al.).

Ota: Non-impact printer paper, Paper and Pulp Technology Times, 27. No. 3 (1984) 45-49).

In these technical aspects, if the problems of coated paper for printing in electrophotography can be solved, the use of smooth coated paper is considered to be advantageous in terms of image quality. In addition, it has been confirmed that smooth coated paper is better for fixing images with emphasis on gloss and color reproduction, as well as for electrophotography, as well as for printing.

Transfer paper for electrophotography that is closest to coated paper is transfer paper for magnetic component development (Japanese Patent Publication No. 58-26026, Japanese Patent Publication No. 57-24716, Japanese Patent Publication No. 57-53592).
No., Special Publication No. 57-55139).

This transfer paper is made by coating the base paper with a paint mainly composed of high electrical resistance resin in order to improve the image disturbance caused by the low electrical resistance of the magnetic component developer. The coating amount is small in order to resemble that of , and the surface is low and smooth, making it unsuitable for the above-mentioned high image quality applications. The same pigments used in the coating for coated printing paper are also included in the coating for this transfer paper.

However, in the case of coated paper for printing, large amounts of pigment are blended mainly for the purpose of smoothing, whereas pigments are blended to resemble plain paper, and when blended in large amounts, the effect of high electrical resistance resin The amount of pigment added in the paint is significantly lower than that of coated paper for printing, in order to reduce the Therefore, simply increasing the coating amount of paint on this transfer paper does not provide the same level of smoothness as coated paper for printing, and also causes problems such as blocking between the sheets, making it unsuitable for use as transfer paper for electrophotography. I can not use it.

[Problems to be Solved by the Invention] An object of the present invention is to improve the above-mentioned drawbacks of the prior art, and to obtain high-quality copies without double feeding or paper jams during paper feeding in an electrophotographic copying machine. An object of the present invention is to provide coated paper for electrophotographic transfer.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention provides an image-receiving layer having a surface centerline average roughness of 2.0μ or less, which is deposited on at least one side of a base paper. This is an electrophotographic transfer paper characterized in that the standard deviation of the coefficient of static friction between the sheets is adjusted to 0.05 or less.

Regarding the influence of paper on the color reproduction of printing, see J.
A, C, Yu Ie has a higher paper surface cross, and the lower the ink absorption, the less the ink color will deteriorate, and the coated paper will produce sharper images than the uncoated paper. (J, A, C, YuIe: Pr1
nciplesof Co1or Reprodu
ction.

JOHN WILEY & 5ONS, INC.
.

1967).

The present inventors evaluated the color deterioration of color toner for electrophotography using commercially available coated printing paper, high-quality paper, and prototype coated paper.As with printing, coated paper was superior to high-quality paper. It was confirmed that there was little color deterioration. For these papers, use the GARDNER gloss meter GARDNER GLO.
Measured using 3SGARDI. In addition, the center line average roughness was measured using a universal surface profile measuring device 5u manufactured by Kosaka Institute Co., Ltd.
JISB using rfcorder 5E-3G
According to the method of O601, the measurement was performed with a cutoff value of 0.8 and a measurement length of 81rIIr4, and the relationship between loss and center line average roughness as shown in FIG. 1 was obtained. From this result, for cloth, the boundary between coated paper and high-quality paper with less color deterioration is 10
%, matte-finish coated paper and high-quality paper exist in this area, making it difficult to distinguish between the two, whereas for the center line average roughness, if the boundary value is 2μ, it is possible to clearly distinguish between the two. There was found. Furthermore, in order to develop color toner sufficiently, the toner needs to be sufficiently melted during fixing, and the cross becomes high, so if the cross of the paper is too low, uneven gloss in the copy will increase, which is not preferable.

From this point, the center line average roughness of the paper surface is 20% for cloth.
The thickness is preferably 1.5 μm or less.

The electrophotographic transfer paper of the present invention is made by coating at least one side of the base paper with a paint mainly containing pigments and adhesives with low adhesion, and optionally containing an anti-adhesion agent to smooth the surface.
It is obtained by adjusting the standard deviation of the coefficient of static friction between papers to be 0.05 or less.

The pigment, which is the main component of the paint, has an average particle size of 1.5 because the coated surface is smoothed using a super calender etc. after coating.
Fine particles of 1.0 μm or less, preferably 1.0 μm or less, are suitable, such as heavy calcium carbonate, light calcium carbonate, kaolin clay, sericite, gicrite, calcined clay, aluminum hydroxide, lithopone, zinc oxide, Examples include titanium dioxide, barium 'fiM acid, silica, and urea resin pigments. Particularly desirable are heavy and light calcium carbonate, calcined clay, etc. as small pigments that are easy to smooth and adhere.

As the adhesive, water-soluble adhesives, emulsions, and latexes, which have strong adhesion to pigments and base paper and have low blocking properties, can be used alone or in combination.

It may not be possible to reduce the standard deviation of the coefficient of friction between papers in a stacked state to 0.05 or less by simply blending the pigment and adhesive. In this case, the improvement measures are to add lubricating chemicals to the coating layer to make it slippery, or to add a small amount of coarse particle pigment within the range that does not reduce the image glossiness, thereby creating an air gap between the sheets. This can be achieved by intervening. Alternatively, by changing the average particle size of the pigment used on the recording surface and the non-recording surface of the coated paper,
A fine particle pigment may be used on the front surface to ensure image glossiness, and a coarse particle pigment may be used on the back surface to provide an air layer.

Examples of chemicals that impart lubricity include fatty acid metal salts such as calcium stearate, fatty acid amides such as stearamide, polyethylene emulsion, and silicone resin powder.

The purpose can be achieved by adding 0.1 to 5% of these lubricants to the paint.

Coarse particle pigments include inorganic pigments such as heavy calcium carbonate, aluminum hydroxide, clay, and talc, and organic pigments such as polyvinyl alcohol powder, epoxy resin powder, and polypropylene resin powder, with an average particle size of 2 to 20 μm. be.

When blending these coarse particle pigments on the non-recording surface, the entire amount of the pigment may be coarse particle pigments, but when blending on the recording surface, the amount must be adjusted to an extent that does not reduce the image quality and glossiness, that is, 1 to 1.
It is necessary to keep it at 0%.

As the coating method, general coating methods such as blade coating, air knife coating, roll coating, bar coating, etc. can be used.

The smoothing treatment can be performed by passing the material through the nip between a rigid roll and an elastic roll many times using a super calender or a cross calender.

The smoothing process is performed using JISBO to obtain sufficient image glossiness.
The center line average roughness of the surface according to 601 is 2゜0LITrL
Hereinafter, it is necessary to adjust the thickness to preferably 1.5 μm or less.

In order to obtain the required center line average roughness, it is not possible to control it only by the smoothing process, but it is also necessary to consider the pigment particle size, blending ratio, coating amount, and coating method.

As the base paper, acidic or neutral high-quality paper or medium-quality paper can be used. However, in order to provide suitability for electrophotographic copying machines such as runnability and curling properties, the blending, preparation, and manufacturing conditions of the raw materials must be adjusted according to known methods. Method (Special Publication No. 55-47385, Special Publication No. 57-812)
Paper controlled by No. 70) is preferable.

In addition, as for the cutting method, it is necessary to select conditions that are unlikely to cause adhesion of the paper surface or the cut surface. In this respect, rotary cutting is preferable to guillotine cutting.

[Examples] The present invention will be explained in more detail below using Examples and Comparative Examples. In the following examples, parts represent parts by weight.

Example 1 Hardwood bleached kraft pulp (LBK) with a beating degree of 500CG
P) 65g/butt paper was made by adding 10 parts of talc, 2 parts of starch, 1.5 parts of rosin sizing agent and 1 part of sulfuric acid to 90 parts of softwood bleached kraft pulp (NBKP) with a freeness of 460 cc. Light calcium carbonate (Brillian 1 to 15, average particle size 0.15 μm, manufactured by Shiraishi Kogyo Co., Ltd. > 80 parts, SBR latex (JSRO662
゜Japan Synthetic Rubber Co., Ltd.) 15 parts, oxidized starch (Ace A.

The coating amount after drying of the paint containing Tamago Cornstarch Co. rA>5 parts and 1 part of calcium stearate (Nobucoat C-104, manufactured by San Nopco Co., Ltd.) as a lubricant is as follows: Felt side (F side) / Wire side (W side) =12/12g/T
After coating with a blade coater so as to have the following properties, copying paper was obtained by supercalendering.

Example 2 Light calcium carbonate (
Brilliant 15. average particle size 0.15 μm, manufactured by Shiraishi Kogyo Co., Ltd.) 75 parts, heavy calcium carbonate (N
N500. Average particle size: 4.4 μm (manufactured by Nitto Funka Kogyo Co., Ltd.) 5
Part, acrylic-vinyl vinegar emulsion (Movinyl 630.
A paint consisting of 15 parts of Hoechst Synthetic Co., Ltd.) and 5 parts of oxidized starch (Ace A, Tamago Cornstarch Co., Ltd.) was applied using an air knife coater so that the coating amount after drying was F side/W side = 15/15 g/TIt. After coating, smoothing treatment was performed using a super calendar to obtain copy paper.

Example 3 Kaolinite clay (
Ultra Gloss 90. Average particle size: 0.3 μm, manufactured by EMC Co., Ltd.) 60 parts, wet-pulverized calcium carbonate (Cartal 95)
．． Average particle size 0.5 μm, manufactured by Fuji Kaolin Co., Ltd.) 25 parts, S
BR latex (JSRO693, manufactured by Japan Synthetic Rubber Co., Ltd.)
13 parts, oxidized starch (Ace A, Tamago Cornstarch Co., Ltd.) 2 parts, calcium stearate (Nobucoat C-10)
4゜Manufactured by San Nopco Co., Ltd.) 0.3 part of paint was applied with a blade coater so that the coating amount after drying was F side/W side = 13/13 g/m, and then supercalendered and coated on copy paper. I got it.

Example 4 Kaolinite clay (Ultra Gloss 90. Average particle size 0.3 μrrt, E
MC) 60 parts, wet-ground calcium carbonate (Cartal 95. Average particle size 0.5 μm, Fuji Kaolin) 25
13 parts of SBR latex (JSRO693, manufactured by Japan Synthetic Rubber Co., Ltd.), 2 parts of oxidized starch (Ace A, manufactured by Tamago Corn Starch Co., Ltd.), and 0.3 parts of calcium stearate (Nobu Coat C-104, manufactured by San Nopco Co., Ltd.) was coated with a blade coater so that the coating amount after drying was 139/7d to form the recording surface, and 60 parts of heavy calcium carbonate (NS-100, average particle size 2.1 μm, manufactured by Nitto Funka Co., Ltd.) was applied to the W side. , cornstarch particles (average particle size 9.8μ
(manufactured by Egg Corn Starch Co., Ltd.) 5 parts, acrylic-vinegar vinegar emulsion (Movinyl 630. manufactured by Hoechst Synthetic Co., Ltd. > 3
0 parts of polyvinyl alcohol (Poval 117, manufactured by Kuraray Co., Ltd.) and 0.3 parts of calcium stearate (Nobu Coat C-104, manufactured by San Nopco Co., Ltd.) using an air knife so that the coating amount after drying was 13 g/7 Ff. After coating with a coater, smoothing treatment was performed with a super calendar to obtain copy paper.

Example 5 On one side of the high-quality paper used in Example 1, 87 parts of kaolin clay (Ultra Why 1-90, manufactured by EMC), 10 parts of styrene-butadiene latex (JSRO632, manufactured by Japan Synthetic Rubber Co., Ltd.), and oxidized starch ( After drying the paint consisting of 3 parts (Ace A, manufactured by Tamago Cornstarch Co.), the amount of paint applied is F side =
After coating with a blade coater to give a coating density of 15 g/Td, a smoothing process was performed using a super calendar to obtain copy paper.

The sheets of Examples 1 to 5 were cut using a rotary small cutting machine to obtain copy sheets of appropriate sizes.

Comparative Example 1 87 parts of kaolin clay (Ultra White 90, manufactured by EMC) and styrene were applied to both sides of the high-quality paper used in Example 1.
After drying, apply a paint consisting of 10 parts of butadiene latex (JSRO632, manufactured by Japan Synthetic Rubber Co., Ltd.) and 3 parts of oxidized starch (Ace A, manufactured by Tamago Cornstarch Co., Ltd.) @1 is the F side/
W side = 15/15 g # After coating with a blade coater, smoothing treatment was performed with a super calendar to obtain copy paper.

Comparative Example 2 Commercially available coated printing paper OK special art (manufactured by Tamako Paper Co., Ltd. >84
．． 9g/7Ff.

Comparative Example 3 Commercially available coated printing paper New Gold! <Manufactured by Kanzaki Paper Company) 8
4.9g/Td.

Comparative Example 4 Commercially available one-component magnetic toner development system Mita Kogyo Mita DC-
131 PPC paper for copying machines.

Comparative example 5 Commercially available Xerox L paper manufactured by Fuji Xerox.

Regarding the papers listed in Examples 1 to 5 and Comparative Examples 1 to 4, (1) basis weight, (2) thickness, (3) center line average roughness, (
4) Surface electrical resistance, (5) Air permeability, (6) Static friction coefficient,
(7) Highlight chroma, (8) blank paper cross, (9) solid image cross, and (10) number of running troubles were measured and evaluated using the following methods, and the results are shown in Tables 1 and 2. .

(1) Basis weight: Measured by the method of JISP8124.

(2) Thickness: Measured by the method of JISP8118.

(3) Centerline average roughness: A test piece was pretreated according to the method of JISP81'11, and the F side was measured according to the method of JISBO601.

Measuring instrument used: Manufactured by Kosaka Laboratory Co., Ltd.

Universal surface profile measuring instrument 5urfcorder 5E-3C Cut-off (straight 0.8 foot measurement length 8IrI!n (4) Surface electrical resistance: Pre-treat the test piece according to the method of J I5P8111 and the pre-treatment method for each. under the same conditions as
The F-plane was measured by a method according to JISC2122 surface resistivity.

Measuring instrument used: Manufactured by Kawaguchi Electric Manufacturing Co., Ltd.

Room temperature measurement box P-601 HIGHRESISTA NCE METER 329A manufactured by Yokogawa Hewlett Packard Card Co., Ltd. Applied voltage: 100V (5) Air permeability: Measured by the method of JISP8117.

(6) Static friction coefficient: After smoothing the papers of Examples and Comparative Examples, they were cut into A4 size sheets of 500 sheets each using a guillotine cutting machine, and approximately 100 consecutive sheets in a stacked state, excluding the top few dozen sheets, were cut into A4 size sheets. was used as the test sample.

Regarding commercially available paper, the package was opened and about 100 consecutive sheets in the same stacked state as above were used as test samples.

J, TAPPI No. 30, fix the test sample on a horizontal plate of size 84, fix the top one of the test sample and the bottom of the weight with double-sided adhesive tape, and apply it sequentially up to the 10th plate. It was measured.

Measuring instrument used: Manufactured by Toyo Baldwin.

Tensilon UTM-m-100 (7) Highlight chroma: Using a Fuji Xerox Co., Ltd. 3890 copier, use magenta toner to transfer an unfixed transfer image of a 175-line 5-85% halftone gradation image to the F side. Formed. Thereafter, the image was fixed using a double-sided heat fixing device consisting of a silicone rubber coated roll.

Spectral colorimetry is performed using the JIS Z8722 method for each halftone gradation, x, y, and Y are calculated, and JIS Z8721 is calculated from the values.
The saturation C was determined by the method described above. Further, the halftone dot area ratio of the same halftone dot was measured, and the relational expression between the saturation C and the halftone dot area ratio was determined by the least squares method. Using this relational expression, the saturation C when the dot area ratio is 0.4 was calculated and used as a highlight chroma.

Measuring instrument used: Manufactured by Hitachi, Ltd.

3pectrophotometer H330 manufactured by Toyo Ink Co., Ltd., BEUVAC (8) Blank paper gloss: F side was measured by a method according to JISP8142.

Measuring instrument used: Manufactured by GARDNER.

GARDNERGLO8 SGARDI[I (9) Solid image gloss: A magenta solid image was obtained on 8 sides by the same method as the highlight chroma. This solid image cloth was measured in the same manner as the blank paper cloth.

(10) Number of running troubles 2. 5 sheets of accumulated paper collected in the same manner as the static friction coefficient.
00 sheets each in the paper feed tray of a Fuji Xerox 5870 copying machine, make 1000 copies of each sheet (100 sheets for 1. Comparative Examples 1 and 2.3), and check for paper jams, double feeds, etc. The total number of troubles was taken as the number of running troubles.

From the results shown in Tables 1 and 2, it is clear that driving troubles
In order to reduce the number of times per 1,000 sheets to 5 times or less, the standard deviation of the coefficient of static friction between stacked sheets should be 0.05 or less, and to reduce running trouble to almost zero, the standard deviation should be 0.02 or less. It is clear that there is a need.

In addition, with single-sided coated paper as in Example 5, it is relatively easy to adjust to these levels, but the curl after fixing becomes very large. Construction paper is preferable.

[Effects of the Invention] The present invention provides an image-receiving layer having a surface centerline average roughness of 2.0 μm or less on at least one side of the base paper, and adjusts the standard deviation of the coefficient of static friction between the papers in a stacked state to 0.05 or less. This product provides transfer paper for electrophotography, and has the feature of producing high-quality copies without double feeding or paper jams during paper feeding.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the cross and center line average roughness of various types of paper.

Claims (1)

[Claims] An electronic device characterized in that a transfer layer having a surface center line average roughness of 2.0 μm or less is provided on at least one side of the base paper, and the standard deviation of the coefficient of static friction between the papers in a deposited state is adjusted to 0.05 or less. Photo transfer paper.