JP3477784B2 - Dry electrophotographic transfer paper - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electrophotographic transfer papers, and in particular, dry electrophotographic transfer papers are capable of expressing high quality images like photographs and high-quality printed materials and are suitable not only for monochrome but also for full color. The present invention also relates to a dry electrophotographic transfer paper which is excellent in equipment suitability for high-speed printing and copying.

[0002]

2. Description of the Related Art In delicate multicolor printing represented by offset printing and the like, the surface of the base paper is smooth, and in order to satisfy the impression after printing, the base paper is mainly coated with a pigment and an adhesive. Coated paper called glossy, matte or dull art paper or coated paper is used. In recent years, due to the generalization of DTP and the progress of dry electrophotography, a device capable of supporting full-color, high-definition image quality of 600 dpi, and high printing speed (50 sheets / min or more) has been developed. There is also a strong demand for paper quality that can be used in transfer paper for electronic devices.

Commercially available printing coated papers at present are compared with generally used non-coated dry electrophotographic transfer papers.
Since the surface is smooth, a clear image is provided in electrophotographic recording, but running troubles easily occur in the recording apparatus. Therefore, various proposals have been made as countermeasures. For example, Japanese Patent Publication No. 5-82939 proposes that a specific pigment is used, and the smoothness of the surface layer and the coefficient of static friction between papers are specified. In JP-A-4-291351, a coating layer is formed. An electrophotographic paper has been proposed which contains light calcium carbonate having a specific shape, has a coating amount per one surface of 0.5 to 3.5 g / m ² , and has specified surface smoothness. Both proposals are sufficiently applicable when applied to electrophotographic transfer devices for medium and low speed, but in the case of electrophotographic transfer devices for high speed, the copolymer used in the coating layer. Depending on the type of latex, problems such as adhesion of the coating layer to the heat fixing roll are likely to occur, which seriously affects running and recording image quality. When it comes to high image quality and full-color applications,
Further improvement and countermeasures are required, and in reality, the methods proposed in the past do not provide sufficient runnability, printability, and print quality.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a transfer sheet for electrophotography, and in particular, it is possible to express a high image quality on a dry transfer sheet for electrophotography as high as a photograph or a high-quality printed matter, and not only for monochrome but also for full color. The present invention provides a dry electrophotographic transfer paper which is suitable and has excellent equipment suitability for high-speed printing and copying.

[0005]

According to the present invention, a base paper is provided with a coating layer containing a pigment and an adhesive as main components in an amount of 6 to 30 g / m ² and is used in a fixing method using a heat roll. In transfer paper, the minimum film-forming temperature as an adhesive is 20
Copolymer latex at -40 ° C is added to the pigment at 5-2
5% by weight, and the coated layer was passed through a soft calender having a roll surface temperature of 100 ° C. or more to adjust the paper moisture after finishing to 4% by weight or more and less than 6% by weight. It is a transfer sheet for dry electrophotography.

[0006]

In the image formation on the dry electrophotographic transfer paper, the toner on the photoconductor is transferred onto the paper, and then the toner is fixed on the transfer paper by heat. The main heat fixing method is performed by a heat roll or a flash, and the current mainstream is the fixing method by a heat roll.

With the progress of full-color in dry electrophotography, a large amount of toner is required and a large amount of heat energy is required for fixing, as compared with a single-color toner in order to superpose a plurality of toners. is there. Further, as the speed is increased, it is necessary to fix the toner in a short time, so that much heat energy is required.

When ordinary coated paper is used as a dry electrophotographic transfer paper, the copolymer latex, which is a thermoplastic substance used in the coating layer, adheres to the heat fixing roll, resulting in non-coated paper Compared with photographic transfer paper, the transferability of toner tends to be non-uniform and a clear image tends not to be provided. Further, the transfer paper (coating layer) adheres to the heat fixing roll, winding of the transfer paper occurs, which causes paper jam. In addition, since coated paper is subjected to pressure smoothing treatment such as calendering compared to non-coated paper, at the same actual amount, the paper stiffness (stiffness) is weak due to high tenacity. Jamming and peeling from the heat fixing roll are not smooth inside the electrophotographic apparatus, and running defects easily occur.

For the reasons described above, the inventors of the present invention should use a coated paper as a dry electrophotographic transfer paper that is excellent in full-color, high image quality, high-speed printing and copying suitability (recording equipment suitability). As a result of repeated studies as a result, a copolymer latex having a specific minimum film-forming temperature is used for a coating layer, and the coating layer is subjected to pressure treatment with a calender device having a specific surface temperature, Furthermore, by adjusting the paper moisture after finishing to 4% by weight or more and less than 6% by weight,
The inventors have found that a dry electrophotographic transfer paper excellent in recording suitability, running property and recording image quality can be obtained, and completed the present invention.

That is, the copolymer latex used in the present invention has a minimum film-forming temperature of 20 to 40 ° C., more preferably 25 to 35 ° C., in order to prevent adhesion to the heat fixing roll.
It is important to use a copolymer latex within the range. By the way, if the temperature is lower than 20 ° C, the copolymer latex is rich in thermoplasticity, so that the coating layer is apt to adhere to the heat fixing roll, and further, the transfer paper itself becomes weak and the troubles such as poor running property occur. easy. On the other hand, when the temperature exceeds 40 ° C., the film-forming property of the copolymer latex becomes insufficient and the surface strength is lowered, resulting in peeling of the coating layer called white spots and mixing of coating layer strips with toner. Transfer failure occurs and the image becomes unclear.

Further, when the coated paper is subjected to calender pressure smoothing treatment, when the surface temperature of the calender roll is less than 100 ° C., the minimum film forming temperature is 20 to 20 ° C.
A clear image cannot be obtained because the film formation of the copolymer latex at 40 ° C. is not sufficiently exhibited and the surface smoothness is insufficient. On the other hand, when a copolymer latex having a minimum film forming temperature of higher than 40 ° C. is used, good film formability cannot be obtained even if the roll surface temperature of the calender is 100 ° C. or higher. Furthermore, the roll surface temperature of the calender is preferably set to less than 200 ° C. in consideration of the durability of the elastic roll used.

Further, it is important to adjust the blending amount of the copolymer latex used in the range of 5 to 25% by weight, preferably 7 to 20% by weight, based on the pigment as a solid content. Incidentally, if it is less than 5% by weight, the effect on the rigidity (paper stiffness) is low, and if it exceeds 25% by weight, the porosity of the coating layer deteriorates, and when the toner is fixed by a hot roll, the water content in the transfer paper is reduced. Generation of blisters due to the movement and penetration of the toner into the coating layer are suppressed, and the toner layer is easily peeled off from the transfer paper surface, and a clear image cannot be obtained.

Further, the above-mentioned specific copolymer latex means a synthetic adhesive generally used in the field of ordinary coated paper for printing, and usually takes the form of a synthetic resin emulsion. . Examples of the specific emulsion latex include conjugated gen polymer latex such as styrene-butadiene copolymer, acrylic acid polymer latex and / or methacrylic acid ester polymer or copolymer latex, ethylene-vinyl acetate. A vinyl-based polymer latex such as a copolymer, or an alkali-soluble or non-soluble polymer latex obtained by modifying these various polymer latexes with a functional group-containing monomer such as a carboxyl group can be appropriately used. The method for producing the copolymer latex is not particularly limited, and a method produced by a publicly known and publicly known method may be appropriately used.

In order to further enhance the effects of the present invention, the particle size of the copolymer latex used is 0.07 to 0.2.
It is desirable to set in the range of 2 μm. By the way, 0.
If it is less than 07 μm, the film-forming property is strong and the rigidity and surface strength of the coated paper are improved, but the void property of the coated paper is reduced and the occurrence of blisters and the penetration of the toner into the coating layer are likely to decrease, and the transfer The toner layer is more likely to peel off from the paper surface,
It tends to be difficult to form a clear image. On the other hand, 0.22 μm
When it exceeds, even if the minimum film forming temperature is 20 to 40 ° C., the effect of developing rigidity is small. The reason for the above is that there is a correlation between the minimum film-forming temperature of the copolymer latex and the particle size. For example, even if there are two kinds of latexes having different particle sizes even in the case of the copolymer latex using the same monomer. In order to have the same minimum film-forming temperature, latex with a large particle size is inferior in film forming property, so it is necessary to increase the compounding ratio of a soft monomer, and as a result, it is more rigid than latex with a small particle size. Is declining.

Further, as described above, in the present invention, as a means for improving the smoothness of the surface of the dry electrophotographic transfer paper, finishing by pressure smoothing treatment by a calender is carried out, but it is used in the present invention. When performing pressure treatment with a calender having a roll surface temperature of 100 ° C. or higher using a specific copolymer latex described above, the most effective effect is when finished with a soft calender having 2 to 6 nip. is there.

Of course, as the calender device, a machine calender, a super calender, a gross calender, etc. can be appropriately used in addition to the soft calender.
For example, in the case of machine calendering, the smoothness of the transfer paper surface can be sufficiently improved, but since the calender rolls are all made of chilled rolls (metal), uneven glossiness easily occurs on the white paper surface. However, there is a concern that the appearance of blank paper may be deteriorated.

Further, in the case of the super calender finish, as compared with the soft calender finish, the surface temperature of the chilled roll is generally 80 to 100 ° C., a wide nip width and a multi-stage nip number (8 to 14 nip) are set. Although the smoothness of the surface of the transfer paper is improved because the paper is passed and finished, the tightness of the product is increased and the rigidity is lowered, which easily causes a running trouble in the dry electrophotographic recording apparatus.

Further, in the case of the gloss calendering, since the surface temperature of the chilled roll is 100 ° C. or more and the elastic roll of low hardness (for example, urethane rubber roll) is combined, the smoothing treatment is performed by passing several nip sheets. Although the paper surface is hard to be crushed and it is bulky and has an excellent effect of expressing rigidity,
Even if the copolymer latex specified in the present invention is used, it is difficult to obtain a transfer paper surface having sufficient surface smoothness, and there is a concern that a clear image cannot be obtained as a transfer paper for electrophotography.

On the other hand, the pressure treatment by the soft calender is a smoothing treatment by a combination of a high temperature chilled roll and an elastic roll as in the gloss calender, but the roll surface of a super calender having a multi-stage nip is used. Since the specifications are such that the temperature is higher than the temperature and the elastic roll has a hardness higher than that of the gloss calender, excellent surface smoothness can be obtained, and the relative decrease in rigidity is relatively small. It is possible to finish the electrophotographic transfer paper, which has excellent running properties in the recording apparatus for use and is capable of easily obtaining clear image formation.

The material of the elastic roll used in the soft calender is cotton, polyether resin, epoxy resin, polyurethane resin, aramid resin or the like. However,
If the number of nips is 7 or more, the effect of the present invention cannot be expected because it is similar to the effect of super calender finishing. Further, if the number of nips is one, the smoothing effect is less than in the case of two nips. When performing the pressure treatment with only one nip, it is important to perform treatment so that the coating layer surface (the surface on which the transfer image is obtained) is in contact with the heating roll surface.

Further, in the present invention, it is important to finish the dry electrophotographic transfer paper so that the paper water content is 4% by weight or more and less than 6% by weight. When the content is less than 4% by weight, the desired excellent surface smoothness and surface strength cannot be obtained even if the pressure smoothing treatment is performed by the calendering treatment. On the other hand, when the amount is 6% by weight or more, one side of the transfer recording apparatus comes into contact with a heat roll, and curling occurs, so that satisfactory recording suitability cannot be obtained. The finishing water content can be adjusted as appropriate by adjusting the drying method and conditions after coating, and further adjusting the humidity control conditions such as steam between steps.

In the present invention, various pigments used in the field of coated paper manufacturing can be appropriately used as the pigment which is the main component of the coating layer, and of these, calcium carbonate is particularly preferably used. In that case, the amount of calcium carbonate is preferably 20 to 80% by weight of the total pigment as a solid content. The significance of using calcium carbonate is that it imparts appropriate porosity to the coating layer within a range that does not deteriorate the surface smoothness of the electrophotographic transfer paper, so that the blister generated during fixing of the toner on the hot roll is performed. Is prevented and proper penetration of the toner into the coating layer is performed,
It is easy to obtain a clear recorded image. Incidentally, when the content of calcium carbonate as the pigment is less than 20% by weight, the porosity of the coating layer surface may be reduced, and the occurrence frequency of blisters and the like is likely to increase. On the other hand, 80% by weight
If it exceeds, it is difficult to obtain excellent surface smoothness.

The other pigments used in the present invention are not particularly limited, and pigments commonly used in the field of coated paper can be appropriately used. Specific examples include satin white, calcium sulfite, gypsum,
Barium sulfate, talc, kaolin, clay, calcined kaolin, white carbon, deramikaolin, diatomaceous earth, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, etc., zinc oxide, magnesium oxide , Bend night,
Examples thereof include inorganic pigments such as sericite, polystyrene resin fine particles, urea formalin resin fine particles, and organic pigments such as fine hollow particles. One or more of these can be used in appropriate combination.

In addition to the specific copolymer latex, the adhesive may be various starches, modified starches, casein, gelatin, soybean protein, and so on, as long as the effects of the present invention are not impaired.
Proteins such as synthetic proteins, conjugated diene polymer latexes such as styrene-butadiene copolymers other than the copolymer latex used in the present invention, acrylic acid ester and / or methacrylic acid ester polymers, or copolymers Acrylic polymer latex, ethylene-vinyl acetate copolymer latex, or those obtained by modifying these various copolymer latexes with functional groups such as carboxyl groups, various polyvinyl alcohols, various polyacrylamides, synthetic resin systems such as melamine resins Adhesives, various cellulose derivatives and the like are appropriately selected and used according to the quality design of the electrophotographic transfer paper. The total amount of the adhesive used is 5 to 50% by weight, preferably 10 to 30% by weight of the pigment.
It is adjusted in the range of about wt%.

Further, in the coated layer, a developer, an adhesive, a magnetic powder, a photosensitizer, a conductive treatment agent, a microcapsule, an antifoaming agent, a coloring dye, a fluorescent whitening agent, an ultraviolet ray may be contained in the coating layer depending on the use. Various auxiliaries such as an inhibitor, a dispersant, a plasticizer, a pH adjuster, a release agent, a flow modifier, a solidification accelerator, a water resistant agent, and a water repellent are appropriately mixed.

When the coating material for coating layer is applied to the base paper, the coating layer may be provided in one layer or in multiple layers. Further, as the coating device, for example, a commonly used coating device such as a blade coater, an air knife coater, a roll coater, a bar coater, a curtain coater, a die coater, a chanplex coater, a brush coater, and a size press device is appropriately used. , Coated on both sides or one side of paper. Of course, these devices may be on-machine or off-machine specifications.

The coating amount on the base paper is generally about 3 to 50 g / m ^{2 in} terms of dry weight, but the quality of the dry electrophotographic transfer paper obtained is white paper quality, toner transferability, running performance, or high-speed coating. 6-30g considering the drying capacity in
It is desirable to adjust in the range of about / m ² . As a method of drying the wet coating layer, various publicly known and publicly known methods such as steam drying, gas heater drying, electric heater drying, and infrared heater drying are adopted.

In the present invention, the base paper is pulp,
Addition of fillers, sizing agents, paper strengthening agents, retention aids and various auxiliaries, etc. to improve running suitability and devise condition settings to prevent curling etc., and provide equipment suitability for dry electrophotographic equipment. Paper is made under the above-mentioned conditions for base paper. In this case, the pulp is appropriately selected from chemical pulp and mechanical pulp using plant fibers such as wood fiber and hemp as raw materials, or chemical pulp, waste paper pulp obtained from mechanical pulp, synthetic pulp, inorganic fiber and the like. Can be used.

As the filler, those commonly used in the art are used. For example, ground calcium carbonate,
Light calcium carbonate, calcium sulfite, gypsum, talc, kaolin, clay, calcined kaolin, amorphous silica,
Inorganic pigments such as deramikaolin, diatomaceous earth, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide and zinc hydroxide, organic resin pigments such as polystyrene resin fine particles, urea formalin resin fine particles and fine hollow particles Can be mentioned. Furthermore, pigments contained in used paper, brokes, etc. can be recycled. Further, if necessary, not only one kind but also two or more kinds of fillers can be appropriately combined and used. It is desirable to use calcium carbonate, which is less likely to adversely affect the photoreceptor or toner of the electrophotographic apparatus. Further, when talc is used, it should be limitedly used within a range in which it does not adversely affect the photoconductor and the toner.

During the papermaking of the base paper, in addition to pulp fibers and fillers, various anionic, nonionic, and cationic materials that have been conventionally used are used in the paper stock as long as the desired effects of the present invention are not impaired. Alternatively, an amphoteric retention improver, a drainage improver, a paper strength improver, and an internal addition aid for papermaking such as an internal sizing agent are appropriately selected and used as necessary. For example, polyvalent metal compounds such as aluminum, iron, tin, and zinc (sulfuric acid band, aluminum chloride, sodium aluminate, basic aluminum chloride, basic polyaluminum hydroxide, and other basic aluminum compounds and easily dispersible in water) Water-soluble aluminum compounds such as alumina sol or ferrous sulfate,
Ferric chloride, etc., various sizing agents (alkyl ketene dimer type, alkenyl succinic anhydride type, styrene-acrylic type, higher fatty acid type, petroleum resin type sizing agent, rosin type sizing agent, etc.) and various starches, poly Acrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide-polyamine resin, polyethyleneimine, polyamine, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic crosslinked polymer particle dispersion and derivatives or modified products thereof. Various compounds such as Further, a papermaking internal additive such as a dye, a fluorescent whitening agent, a pH adjusting agent, a defoaming agent, a pitch control agent and a slime control agent may be added depending on the use.

The papermaking method is not particularly limited. For example, the papermaking method may be acidic papermaking having a papermaking pH of about 4.5, or a weak acidity of about 6 with an alkaline filler such as calcium carbonate as a main component. There is no particular limitation as to whether or not the so-called neutral papermaking, which is carried out with a weak alkaline of about 9 to 9, is used. However, for the reasons described above, the neutral papermaking method using calcium carbonate is desirable. Further, as the paper machine, a Fourdrinier paper machine, a twin wire machine, a cylinder paper machine, a Yankee paper machine or the like can be appropriately used.

In consideration of poor runnability and curl trouble, which are apt to be a problem in the dry electrophotographic apparatus, the difference in fiber orientation between the front and back sides of the base paper is taken into consideration as shown in the textbook of the 30th workshop of the Electrophotographic Society. Decrease or,
As shown in Japanese Patent No. 349468, a device for reducing the fiber orientation value is appropriately adopted.

A size press treatment may be performed on the base paper thus produced, if necessary. In that case, the size press liquid includes starches, various modified starches, various water-soluble celluloses,
Various polyvinyl alcohol, various polyacrylamide, latex, alkyl ketene dimer, styrene-
Acrylic-based, olefin-maleic anhydride-based, higher fatty acid-based surface sizing agents, waterproofing agents such as epoxy compounds, optical brighteners, defoamers, wetting agents, antistatic agents, various inorganic pigments, various organic pigments , Dyes, starch particles, and various additives can be added according to the purpose.

The application method of the size press liquid is not particularly limited, and for example, a commonly used size press device such as a two-roll or metering blade type size press, a bill blade size press, a gate roll size press, a calender, and the like. Commonly used coating equipment such as air knife coater, roll coater, pure blade coater, rod blade coater, short dwell coater, gravure coater, metering bar coater, curtain coater, die coater, spray coater, etc. are used as appropriate, paper Is applied to both sides or one side.

Further, in the present invention, in order to prevent occurrence of device suitability defects in the dry electrophotographic apparatus such as transferability and running property, for example, as for transferability, JP-A-57-57
As proposed in Japanese Patent No. 204058, by designing the surface electric resistance value to fall within a specific range, the transfer efficiency of the toner can be improved, and the running property can be improved.
To increase the dimensional stability by suppressing the water immersion elongation value to a low value as disclosed in Japanese Patent Publication No. 142552, or to reduce the expansion / contraction rate of a product as proposed in Japanese Patent Laid-Open No. 5-239792. It is desirable to appropriately adopt a method such as increasing the dimensional stability in order to improve equipment suitability and running property in the transfer recording apparatus. By adding the above-mentioned method, the dry electrophotographic transfer paper of the present invention can be a product which is more excellent in running property and image formation.

[0036]

EXAMPLES The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited thereto. Unless otherwise specified, "parts" and "%" in the examples mean "parts by weight" and "% by weight", respectively.

Example 1 Kaolin (trade name: HT / manufactured by Engelhard) 75
Part, light calcium carbonate (trade name: TP-121-7C
/ Okutama Industry Co., Ltd.) 10 parts, finely ground heavy calcium carbonate (trade name: FMT-90 / Pharmatic Co., Ltd.) 15
0.2 part of sodium polyacrylate was added to 1 part to prepare a pigment slurry. 2 parts (solid content) of oxidatively modified starch (trade name: Ace C / manufactured by Oji Corn Starch) in this pigment slurry, minimum film forming temperature of 30 ° C., particle diameter of 0.11
15 μm of styrene-butadiene copolymer latex (solid content) and water were added to prepare a coating liquid having a solid content concentration of 60%. The coating liquid was made by a neutral paper making method,
Basis weight 64g / m ² of high-quality PPC paper (trade name: SAN ACE / Oji Paper Co., Ltd.) in dry coated amount per one side 20g /
A double-sided coated paper was obtained by coating with a blade coater to a m ² and drying.

The surface temperature of the chilled roll of the obtained coated paper is 140 ° C., and the number of nips is 4 (nip is formed so that each side of the coated paper comes into contact with the chilled roll surface twice).
The elastic roll was subjected to pressure treatment using a soft calender having a Shore D hardness of 90 ° to obtain a dry electrophotographic transfer paper having a paper moisture content of 5.7%. The quality of the dry electrophotographic transfer paper thus obtained was measured by the following evaluation method, and the results are shown in Table 1.

Example 2 In Example 1, the particle size of the copolymer latex was adjusted to 0.
Example 1 except that the thickness was changed from 11 μm to 0.06 μm.
A transfer sheet for dry electrophotography was obtained in the same manner as in. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 In Example 1, the particle size of the copolymer latex was adjusted to 0.
Example 1 except that the thickness was changed from 11 μm to 0.24 μm.
A transfer sheet for dry electrophotography was obtained in the same manner as in. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 In Example 1, the minimum film-forming temperature of the copolymer latex was from 30 ° C. to 35 ° C., and the particle size was from 0.11 μm to 0.1.
The copolymer latex changed to 3 μm was used, and the addition amount was changed from 15 parts to 24 parts, and the surface temperature of the chilled roll of the soft calender was changed from 140 ° C. to 1 ° C.
A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the temperature was changed to 90 ° C. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 5 In Example 1, the minimum film-forming temperature of the copolymer latex was 30 ° C. to 26 ° C., and the particle size was 0.11 μm to 0.13.
Using the copolymer latex changed to μm, the addition amount was changed from 15 parts to 10 parts, and further, 75 parts of kaolin (trade name: HT / Engelhard) 25 parts
Part, light calcium carbonate (trade name: TP-121-7C
/ Okutama Kogyo Co., Ltd.) 10 parts to 30 parts, fine ground heavy calcium carbonate (trade name: FMT-90 / Pharmatic Co., Ltd.) 15 parts to 45 parts, and the surface temperature of the chilled roll of the soft calender was changed. A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the temperature was changed from 140 ° C. to 100 ° C. and the nip number was changed from 4 to 6. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 6 In Example 1, the particle size of the copolymer latex was adjusted to 0.
From 11 μm to 0.22 μm, the base paper on which the coating liquid is applied is a non-coated high-quality PPC paper with neutral papermaking 64 g / m
² (Product name: San-Ace / Oji Paper Co., Ltd.) Non-coated medium quality PPC paper 64g / m ² by acid papermaking (Product name:
New CK paper / manufactured by Fuji Xerox Co., Ltd., except that the number of nips of the soft calendar was changed from 4 to 2
A dry electrophotographic transfer paper was obtained in the same manner as in Example 1. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 7 Example 1 was repeated except that the addition amount (solid content) of the copolymer latex was changed from 15 parts to 6 parts and the addition amount of the oxidation-modified starch was changed from 2 parts to 6 parts. A transfer sheet for dry electrophotography was obtained in the same manner as in. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Reference Example 1 In Example 1, the particle size of the copolymer latex was adjusted to 0.
Example 1 except that the calender was changed from 11 μm to 0.06 μm from a soft calender to a gloss calender equipped with an elastic roll having a Shore D hardness of 60 °.
A transfer sheet for dry electrophotography was obtained in the same manner as in. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Embodiment 8 In Embodiment 1, the number of nips of the soft calender is 4
A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the number was changed from 8 to 8. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Embodiment 9 In Embodiment 1, the number of nips of the soft calender is 4
A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the number was changed to 1. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Reference Example 2 In Example 1, the surface temperature of the calender was 140 ° C.
Then, a dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the soft calender with a nip number of 4 was changed to a super calender with a chilled roll surface temperature of 100 ° C. and a nip number of 12. . Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 10 In Example 1, the minimum film-forming temperature of the copolymer latex was 30 ° C. to 22 ° C., and the particle diameter was 0.11 μm to 0.1.
A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the copolymer latex was changed to 7 μm. And
The quality was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 11 A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the minimum film-forming temperature of the copolymer latex was changed from 30 ° C to 38 ° C. And Example 1
The quality was measured in the same manner as in, and the results are shown in Table 1.

Example 12 A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the water content of the paper after the pressure treatment with the soft calender was 4.1%. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A dry electrophotographic transfer paper was obtained in the same manner as in Example 1, except that the surface temperature of the chilled roll of the soft calender was changed from 140 ° C to 80 ° C. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.
It was shown to.

Comparative Example 2 A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the addition amount (solid content) of the copolymer latex was changed from 15 parts to 4 parts. . Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the addition amount (solid content) of the copolymer latex was changed from 15 parts to 27 parts. . Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4 A dry electrophotographic transfer paper was prepared in the same manner as in Example 1 except that the minimum film-forming temperature of the copolymer latex was changed from 30 ° C. to 15 ° C. Obtained. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.
It was shown to.

Comparative Example 5 A dry electrophotographic transfer paper was prepared in the same manner as in Example 1 except that the minimum film forming temperature of the copolymer latex was changed from 30 ° C. to 45 ° C. Obtained. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.
It was shown to.

Comparative Example 6 A non-coated high-quality PPC paper (trade name: Canon Color Laser Copier Paper (thick) / manufactured by Canon Inc.) having a surface area of 104 g / m ² was used as a dry electrophotographic transfer paper. The quality was measured in the same manner as in, and the results are shown in Table 1.

Comparative Example 7 A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the paper moisture content after the soft calender pressure treatment was 6.2%. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 8 A dry electrophotographic transfer paper was obtained in the same manner as in Example 1 except that the paper moisture content after the soft calender pressure treatment was 3.8%. Then, quality measurement was performed in the same manner as in Example 1, and the results are shown in Table 1.

The 22 kinds of dry electrophotographic transfer papers thus obtained were subjected to quality measurement according to the following evaluation methods, and the quality measurement results are shown in Table 1.

[Evaluation Method] Evaluation in each quality measurement was performed as follows. The minimum film-forming temperature of the copolymer latex is that the wet coating layer of the copolymer latex is provided on a hot plate having a temperature gradient, and the copolymer without cracks is formed in the process of drying the coating layer. The minimum temperature for forming a latex film is defined as the minimum film-forming temperature, and the particle size of the copolymer latex is observed and measured with a microscope. Also,
The water content of the transfer paper was measured according to JIS-P-8127.

(1) Smoothness Smoothness is based on JAPAN TAPPI No. According to 5,
It measured using the smoother smoothness meter.

(2) White paper glossiness The white paper glossiness is in accordance with JIS-P-8142, and an angle of 75
Measured in °.

(3) Stiffness The Clark stiffness was measured according to JIS-P-8143. Paper MD in the test width 30 mm, the critical length in the CD direction determined and calculated and the average value L, Clark stiffness (cm ^3/100) = expressed in L ^3/100.

(4) Dry pick It was evaluated by a RI printability tester. ◯: Good with no picking. Δ: Picks are slightly generated. X: An extremely large number of picks occur.

(5) Evaluation of image quality Full color copying machine (Canon Color Laser Copier 500
/ Made by Canon Inc.) 5-2 was copied on a transfer paper and the image quality was evaluated according to the following evaluation criteria. ◯: The image is clear without any dirt on the back ground or fine gaps in the copied image area. B: There is a slight problem in the image due to dirt on the back ground and fine gaps in the copy image area. Poor: The image is inferior because the back ground is dirty and there are many fine gaps in the copied image area.

(6) Measurement of image gloss Four-color solid printing was performed on an offset printing machine with commercially available art paper, and a full-color copying machine (Canon Color Laser Copier 500 / Canon) was used to make a copy. The luster of the object conforms to JIS-Z-8741, and an angle of 60
Measured in °.

(7) Evaluation of running property 100 sheets of transfer paper were copied in full color by using a full color copying machine (Canon Color Laser Copier 500 / Canon), and further, a high speed monochrome copying machine (Vivece 5).
00 / manufactured by Fuji Xerox Co., Ltd.)
0 sheets were copied and the running property was evaluated according to the following evaluation criteria. ⊚: Good with no running problems. ◯: Almost no jamming or adhesion to hot rolls is observed. Δ: Jamming and a tendency to adhere to the heat roll are observed,
There is no problem in practical use. X: Jamming or adhesion to a hot roll occurred, causing a running problem.

[0069]

[Table 1]

[0070]

As is clear from the results of Table 1, the dry electrophotographic transfer papers obtained in the examples of the present invention were excellent in the device characteristics in the electrophotographic recording apparatus and the image quality of the transferred image. .

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-291351 (JP, A) JP-A-3-294600 (JP, A) JP-A-4-163399 (JP, A) JP-A-63- 266460 (JP, A) JP 55-88069 (JP, A) JP 50-159742 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 7/00

Claims (4)

(57) [Claims] 1. A base paper is provided with a coating layer containing a pigment and an adhesive as main components in an amount of 6 to 30 g / m ^{2 and is} formed by a heat roll.
In a dry electrophotographic transfer paper used in a fixing system, a copolymer latex having a minimum film forming temperature of 20 to 40 ° C. as an adhesive is contained in an amount of 5 to 25% by weight based on a pigment, and the coating layer is 100%. Sof having a roll surface temperature of ℃ or more
And fed to the door calender, the paper moisture after finishing 4 wt%
As described above, the dry electrophotographic transfer paper is adjusted to less than 6% by weight. 2. The particle size of the copolymer latex is from 0.07 to
The dry electrophotographic transfer paper according to claim 1, having a thickness of 0.22 μm. 3. The minimum film-forming temperature of the copolymer latex is 25.
The dry electrophotographic transfer paper according to claim 1 or 2, which has a temperature of about 35 ° C. 4. The dry electrophotographic transfer paper according to claim 1, 2 or 3, wherein the calender is a soft calender having 2 to 6 nip.