JPH0830011A - Electrophotographic transfer paper - Google Patents

Abstract

PURPOSE:To provide an electrophotographic transfer paper having excellent sizing property and toner fixing property and also having adaptability for an ink-jet method. CONSTITUTION:This electrophotographic transfer paper is produced by coating the surface of a base paper with a styrene-acrylate copolymer or styrene- methacrylate copolymer as a surface sizing agent by 0.01 to 0.20g/m<2>. This base paper is produced by making sheets from a paper slurry to which calcium carbonate as a filler and a nonreactive emulsion sizing agent having a- hydroxycarboxylic acid structure in the main component as an inner sizing agent are added. By this method, the obtd. paper has stable sizing property, excellent fixing property of a toner and adaptability for an ink-jet method without causing feathering when the paper is printed by an ink-jet printer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electrophotographic transfer paper having improved size, electrophotographic suitability, and ink jet suitability. More specifically, the present invention relates to a transfer paper for electrophotography, which has excellent toner fixing properties in the electrophotographic system and feathering properties in the inkjet system.

[0002]

2. Description of the Related Art Conventionally, when paper is manufactured, a method of making paper in an acidic area using a sulfuric acid band and a rosin-based sizing agent has been the mainstream, but in recent years, the usage rate of waste paper has increased and inexpensive carbon dioxide has been used. Calcium has come to be used as a filler, and paper is gradually produced in the neutral region from the acidic region.

Examples of the application of such a neutral papermaking technique to electrophotographic transfer papers include JP-A-59-162560, JP-A-61-63854, and JP-A-61-67038.
JP-A No. 62-6994 and the like, but these publications disclose alkyl ketene dimer (hereinafter abbreviated as AKD) and alkenyl succinic anhydride (hereinafter abbreviated as ASA) as sizing agents. There is. AKD
Has been used because it is easy to handle or has the advantage that excellent sizing can be obtained by adding a small amount of it.

However, these sizing agents are not without problems. AKD has a slow rise in size, and it is difficult to finely control size.
Further, ASA has the drawback that the stability of the sizing agent is poor and that stains easily form from the press section to the dryer section during papermaking.

As a measure against the above problems, the amount of AKD or ASA added is reduced, and the combined use with a cationic polymer type neutral sizing agent typified by a styrene-dimethylamino ether (meth) acrylate-epihalohydrin modified product (JP JP-A-55-132789 and 5
7-112497), and an increase in the surface size starch coating amount and the like have been attempted.

On the other hand, these electrophotographic transfer papers are not always used only for their original purpose in the general market, but are increasingly used as printing papers for ink jet printers. However, if the sizing degree is not sufficient, ink bleeding occurs along the wood fibers, such as feathering, and print quality is degraded.

[0007]

In the case of neutral paper, a technique applicable to obtain an electrophotographic transfer paper excellent in size and toner fixing property is as follows.
There are reductions in the amount of KD and ASA added, combined use with cationic polymer type neutral sizing agents, and increased surface size starch coverage. However, if the addition amount of AKD or ASA is reduced, the fixing property of the toner is good, but a paper of sufficient size cannot be obtained. When a sufficient size cannot be obtained, when printing with an inkjet printer, the print density may be poor or feathering may occur. Further, the combined use system with a cationic polymer type neutral sizing agent is not preferable because problems such as poor disintegration property of broke and reduction of fluorescence intensity of the fluorescent dye remain.

On the other hand, in the case of increasing the amount of surface-sized starch adhered,
In some cases, the curl of the paper is deteriorated, and the feathering is rather deteriorated when printed by an inkjet printer. In either case, it was not possible to obtain a transfer paper for electrophotography of sufficient quality in terms of both electrophotographic suitability and inkjet suitability.

Therefore, an object of the present invention is to provide an electrophotographic transfer paper which is suitable for electrophotography such as sizing property, toner fixing property and paper feeding property and has no feathering when printed by an ink jet printer.

[0010]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of the above, the present inventors have invented the electrophotographic transfer paper of the present invention. That is, the electrophotographic transfer paper of the present invention, calcium carbonate as a filler and a synthetic sizing agent having an α-hydroxycarboxylic acid structure as a main component as an internally added sizing agent is added to the pulp slurry on the surface of the base paper to make paper, As a surface sizing agent, a styrene / acrylic acid type copolymer or a styrene / methacrylic acid type copolymer is used in an amount of 0.01 to 0.
It is characterized by being coated with 20 g / m ² .

The present invention will be described in detail below.

When the present inventors consider the electrophotographic transfer paper of the present invention, the internal sizing agent added to the base paper of the electrophotographic transfer paper of the present invention and the surface size coated on the surface of the base paper. The agents were examined.

As mentioned above, when calcium carbonate is used as the filler, the sizing agent that can be used is A
Examples include KD, ASA, and recently developed neutral rosin sizing agents. The neutral rosin sizing agent refers to, for example, dissociation of the carboxylic acid of the sizing agent in a neutral to alkaline pH range as described on pages 31 to 34 of Paper and Paper Cooperative Journal Vol. The rosin is subjected to a special hydrophobizing modification so as to prevent salt formation with Ca ions and the like, and to retain the pulp in an effective form as a sizing agent.

When these sizing agents are compared again in terms of operability and size development behavior at the time of use, with respect to AKD, sizing characteristics are exhibited in a smaller amount than other sizing agents. Therefore, there is almost no stain on the machine during operation. However, the sizing property is not sufficiently manifested immediately after the papermaking, and the amount of addition may increase in some cases. These excessively added sizes unnecessarily reduce the surface free energy of the paper and impair the adhesion between the toner and the paper when printed by the electrophotographic method. In addition, since the sizing property changes with time, it is difficult to control the sizing property, and it is difficult to stabilize the printing quality when printing with an inkjet printer.

As for ASA, the rising of the size is certainly better than that of AKD, and the quality control of the size is easy. However, the stability of ASA itself is
Since it is worse than KD, dirt easily occurs from the press section of the paper machine to the dryer section.

The neutral rosin sizing agent also has a good rise in size, but during the circulation of the sizing agent in the papermaking system,
A rosin substance that has not been subjected to hydrophobic modification is eluted from the emulsion and bubbles are easily generated, or stains are easily generated from the press section of the paper machine to the dryer section.

A good rise in sizing property such as ASA and neutral rosin sizing agent is essential for controlling the sizing property related to ink jet suitability by preventing the addition of an excessive sizing agent during papermaking. I think there is. However, it is a reality that sizing agents that have hitherto been put on the market have poor operability and that stable operation is difficult.

Therefore, as a result of intensive investigations by the present inventors,
By using a non-reactive emulsion sizing agent having an α-hydroxycarboxylic acid structure as a main component of the sizing agent as an internally added sizing agent for the electrophotographic transfer paper of the present invention, it is possible to obtain a suitable operability under appropriate operability. It was found that the base paper for electrophotographic transfer paper of the present invention having a size property can be obtained.

In the present invention, the main component of the sizing agent is α-
The non-reactive emulsion sizing agent having a hydroxycarboxylic acid structure refers to, for example, those described in p218 to 220 of the abstract of the 1993 annual meeting of the Japan Pulp and Paper Technology Association.

The non-reactive emulsion sizing agent having an α-hydroxycarboxylic acid structure requires the presence of a sulfuric acid band to express the size, and the amount of the sulfuric acid band added varies depending on the papermaking pH at the time of paper making. Pulp is preferably in the range of 0.5 to 1.5% by weight.

The amount of the sizing agent added is 0.
The range of 10 to 0.40% by weight is desirable. When the added amount of the sizing agent is 0.10% by weight or less, no expression of sizing property is observed, and when it is 0.40% by weight or more, the sizing agent itself is stable, but the press part or dryer part of the paper machine is not stained. It begins to occur.

Next, a base paper containing calcium carbonate as a filler and prepared as a sizing agent by changing the addition amount of a non-reactive emulsion sizing agent having an α-hydroxycarboxylic acid structure as its main component in several stages, The toner fixability and the print quality with an inkjet printer were investigated, but the toner fixability surely deteriorates as the amount of the sizing agent added increases. On the other hand, the ink is completely bleeded on the base paper having a low ink jet print quality (for example, a Steckigt size degree of 7 seconds or less). The print quality was not so good even on a base paper having a relatively high sizing degree in which the amount of the sizing agent added was increased (for example, a Steckigt sizing degree of about 20 seconds).

As a result of further studies on the above problems, 0.01 to 0.20 g of a styrene / acrylic acid type copolymer or a styrene / methacrylic acid type copolymer as a surface sizing agent on the surface of the base paper. It was found that the application of / m ² can improve the toner fixing property in the electrophotographic system and the printing quality when printing with an inkjet printer.

In electrophotographic printing, toner particles are transferred from the surface of the photosensitive drum to the surface of the paper, and thereafter,
The copy is completed by heat-bonding with the heat roll of the fixing device. The binder for toner plays the role of this thermal adhesion. Today, a styrene / acrylic acid copolymer is predominantly used as the binder for the toner. For good toner fixability, it is necessary for the toner softened by heat to wet the paper surface during the above heat fixing. However, in the base paper having a low surface free energy, the softened toner is not sufficiently wet and the fixability is deteriorated.

However, by coating the surface of the paper with a surface sizing agent having a component similar to that of the binder for toner, that is, a styrene / acrylic acid type copolymer or a styrene / methacrylic acid type copolymer, At the time of transfer by the photographic method, the wettability of the toner softened by heat to the paper surface is improved, and the fixing property of the toner is improved as a result.

On the other hand, by coating the surface of the base paper with the surface sizing agent, the printing quality when printing with an ink jet printer is improved.

Usually, by increasing the sizing property by using the internally added size, the print density and the blurring of the image printed by the ink jet printer are certainly improved, but the blurring is not completely suppressed. In particular, it is difficult to completely prevent feathering caused by ink bleeding along the wood fibers on the paper surface.

With regard to the internally added size, the wood fiber surface can be covered with a sizing agent by increasing the amount of addition, and the sizing property of the entire paper can be improved. In general, the fiber surface cannot be coated with the sizing agent. Therefore, in terms of sizing on a scale of each fiber, it is considered that unevenness in sizing is likely to occur in the surface direction and the thickness direction of the paper.

By coating the above-mentioned surface sizing agent on the base paper having uneven size in such a minute region, the size of the electrophotographic transfer paper of the present invention is improved and the size is improved. I found that the unevenness disappeared.

As the surface sizing agent which has been recognized to have an effect of improving the printing quality in an ink jet printer, the main components are styrene / acrylic acid type copolymers, styrene / methacrylic acid type copolymers, acrylonitrile / vinyl formal / Examples thereof include acrylic acid ester copolymers, olefin / maleic acid type copolymers, styrene / maleic acid type copolymers, and AKD type surface sizing agents. However, the remarkable effect of improving the toner fixing property at the time of transfer in the electrophotographic system described above is recognized as the surface size of the styrene / acrylic acid copolymer or the styrene / methacrylic acid copolymer system. Was only.

The coating amount of the surface sizing agent is 0.0
1 to 0.20 g / m ² is desirable. When the coating amount is less than 0.01 g / m ² , it is insufficient to improve the fixing property of the toner and the printing quality of the inkjet printer. 0.2 coating amount
Even if it exceeds 0 g / m ² , the effect of improving the fixing property of the toner and the print quality of the inkjet printer will be saturated.

As a method for applying the above-mentioned surface sizing agent by a size press, a conventional size press, a gate roll size press, a film transfer type size press, a rod coater, a bill blade, a short dwell coater or the like is used. be able to. At the same time, it is possible to apply starch, binders such as polyvinyl alcohol, dimensional stabilizers such as ethylene-urea resin, inorganic conductive agents such as sodium chloride and potassium chloride, organic conductive agents, surfactants, pigments and dyes. Of course it is possible.

The wood pulp used in the present invention includes NBKP, LBKP, NBSP, LBSP and G.
In addition to P, TMP, etc., there is used waste paper pulp. In use, several kinds of them are mixed and used at a ratio according to the purpose. The mixing ratio of the waste paper pulp in the total pulp is preferably 40% or less in order to prevent curling after transfer in the electrophotographic copying machine.

As the raw material for waste paper pulp referred to in the present invention, top white, ruled white, cream white, card,
Special white, medium white, imitation, fair white, Kent, white art, special cut,
Examples include separate papers, newspapers and magazines. Further specific examples include non-coated computer paper which is information related paper, printer paper such as thermal paper and pressure sensitive paper, and OA waste paper such as PPC paper, art paper, coated paper, lightly coated paper and matte paper. Coated paper or fine paper, fine color, notebook, notepaper, wrapping paper, fancy paper, medium quality paper, newsprint, waste paper,
Waste paper such as super-wrapping paper, imitation paper, pure white roll paper, uncoated paper such as milk carton and paperboard, chemical pulp paper,
High-yield pulp-containing paper is used, but printing, copying,
It is not particularly limited whether it is printed or not.

As the filler used in the present invention, in addition to calcium carbonate, it is possible to use together various fillers which can be usually used for papermaking.

In addition to the above, various other anionic, nonionic, cationic or amphoteric paper strength improvers which have been conventionally used are contained in the paper stock as long as the desired effects of the present invention are not impaired. An internal additive for papermaking is appropriately selected and used as necessary. For example, various starches, polyacrylamide, polyethyleneimine, polyamine, polyamide
1 of polyamine, urea formalin resin, melamine formalin resin, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, polyamide resin
They may be used either individually or in combination of two or more.
In addition, it is also possible to appropriately add a papermaking internal additive such as a dye, a pH adjuster, an antifoaming agent, a pitch control agent, and a slime control agent according to the purpose.

In the paper making method of the present invention, as the paper machine, a fourdrinier paper machine, a twin wire paper machine, a combination paper machine, a round net paper machine, a Yankee paper machine, and the like known in the papermaking industry can be used appropriately.

[0038]

The electrophotographic transfer paper of the present invention is made by adding calcium carbonate as a filler and a non-reactive emulsion sizing agent having an α-hydroxycarboxylic acid structure as a main component as an internally added sizing agent to a pulp slurry. The surface of the raw paper is coated with a styrene / acrylic acid copolymer or a styrene / methacrylic acid copolymer as a surface sizing agent. With this configuration,
First, since the rise of the sizing property at the frame tip is good, it is easy to control the sizing property. Second
By coating the surface with a styrene / acrylic acid type copolymer or a styrene / methacrylic acid type copolymer, it is possible to prevent the fixability of the toner and the blurring of the ink in the surface layer when printing with an inkjet printer. It For the above reasons, it is possible to provide an electrophotographic transfer paper having electrophotographic suitability and inkjet suitability.

[0039]

EXAMPLES The present invention will be described in detail below with reference to examples. The present invention is not limited to this. All parts and% in the following are by weight.

Example 1 1. Base paper formulation; LBKP (freeness; 350 ml, csf) 70 parts NBKP (freeness; 400 ml, csf) 30 parts Calcium carbonate (Okutama Industrial Co., Ltd .; TP-121) 10 parts Size Agent (Arakawa Chemical Co., Ltd .; KS-951) 0.15 part Sulfuric acid band 1 part Amphoteric starch (Oji National Co .; Cato3210) 1 part Yield improver (Himo Co .; NR-11LS) 0.03 part A 0.3% slurry was used to make a raw paper having a papermaking width of 1,300 mm, a papermaking speed of 150 m / min, a papermaking water temperature of 35 ° C., and a water content of 5.5% and a basis weight of 64 g / m ² by a Fourdrinier paper machine.

A size press was used to apply the following components to the surface of the base paper at the following solid content amounts to prepare a transfer paper for electrophotography of Example 1.

2. Size press coating weight: oxidized starch (Nippon Food Processing Co.; MS-3800) 1.20g / m 2 Sodium chloride 0.06 g / m ² Styrene / acrylic acid copolymer surface sizing agent to the composition (Harima Made by Kasei; KN-500) 0.01 g / m ²

[0043] In Example 1, in the same manner except that the coating amount of surface sizing agent in a size press with 0.10 g / m ^2, Example 2
A transfer paper for electrophotography of was produced.

Example 3 An electrophotographic transfer paper of Example 3 was prepared in the same manner as in Example 1 except that the coating amount of the surface sizing agent in the size press was 0.15 g / m ² .

Example 4 An electrophotographic transfer paper of Example 4 was prepared in the same manner as in Example 1 except that the coating amount of the surface sizing agent in the size press was 0.20 g / m ² .

Example 5 The surface sizing agent in the size press in Example 1 was changed to a surface sizing agent (SS-315 manufactured by Japan PMC Co., Ltd.) having a composition of styrene / methacrylic acid type copolymer, and the coating amount was changed. An electrophotographic transfer paper of Example 5 was prepared in the same manner except that the transfer paper was 0.01 g / m ² .

Example 6 The surface sizing agent in the size press used in Example 1 was changed to a surface sizing agent having a composition of styrene / methacrylic acid type copolymer (manufactured by Japan PMC; SS-315), and the coating amount was adjusted. An electrophotographic transfer paper of Example 6 was prepared in the same manner except that the transfer paper was 0.10 g / m ² .

Example 7 The surface sizing agent in the size press used in Example 1 was changed to a surface sizing agent (SS-315 manufactured by PMC Japan, Inc.) having a composition of a styrene / methacrylic acid copolymer. A transfer paper for electrophotography of Example 7 was prepared in the same manner except that the transfer paper was 0.15 g / m ² .

Example 8 The surface sizing agent in the size press used in Example 1 was changed to a surface sizing agent (manufactured by Japan PMC; SS-315) having a composition of a styrene / methacrylic acid copolymer, and the coating amount was adjusted. An electrophotographic transfer paper of Example 8 was produced in the same manner except that the amount was 0.20 g / m ² .

Example 9 In Example 1, the addition amount of the internally added sizing agent was 0.25 part,
The coating amount of the surface sizing agent with the size press liquid is 0.10 g /
A transfer paper for electrophotography of Example 9 was produced in the same manner except that m ² was used.

Example 10 In Example 1, 0.40 part of the internally added sizing agent was added,
The coating amount of the surface sizing agent with the size press liquid is 0.10 g /
A transfer paper for electrophotography of Example 9 was produced in the same manner except that m ² was used.

Comparative Example 1 In Example 2, 0.5 part of the sulfuric acid band and AKD (manufactured by Arakawa Chemical Co., Ltd .; Size Pine K903) were used as internal sizing agents.
A transfer paper for electrophotography of Comparative Example 1 was produced in the same manner except that the amount was 10 parts.

Comparative Example 2 In Example 2, 0.5 part of the sulfuric acid band and the internally added sizing agent were ASA (manufactured by Oji National Co .; Fibran 68).
A transfer paper for electrophotography of Comparative Example 2 was produced in the same manner except that the amount was 0.10 part.

Comparative Example 3 Comparative Example 3 was the same as Example 2 except that the internally added sizing agent was a neutral rosin sizing agent (Arakawa Chemical Co., Ltd .; Size Pine NT-80) and the addition amount was 0.30 part. A transfer paper for electrophotography No. 3 was prepared.

Comparative Example 4 In Example 1, the coated amount of oxidized starch in the size press was 1.20 g / m ² , and the coated amount of sodium chloride was 0.06 g / m ^2.
Then, an electrophotographic transfer paper of Comparative Example 4 was prepared in the same manner except that the surface sizing agent was not applied.

Comparative Example 5 Comparative Example 5 was carried out in the same manner as in Example 1 except that the coating amount of the surface sizing agent in the size press was 0.005 g / m ^2.
A transfer paper for electrophotography of was produced.

Comparative Example 6 Comparative Example 6 was carried out in the same manner as in Example 5 except that the coating amount of the surface sizing agent in the size press was 0.005 g / m ^2.
A transfer paper for electrophotography of was produced.

Comparative Example 7 In Example 2, the surface sizing agent in the size press was replaced by the olefin-maleic acid surface sizing agent Polymaron 13
A transfer paper for electrophotography of Comparative Example 7 was prepared in the same manner except that it was 29 (manufactured by Arakawa Chemical Co., Ltd.).

Comparative Example 8 In Example 2, the surface sizing agent in the size press was A
KD type surface sizing agent SS-362 (manufactured by Japan PMC)
A transfer paper for electrophotography of Comparative Example 8 was produced in the same manner except that the above was used.

The electrophotographic transfer papers prepared in Examples 1 to 10 and Comparative Examples 1 to 8 were evaluated by the following evaluation methods, and the results are shown in Table 1. [Operability] The operability during the papermaking process was evaluated by visually observing the stain condition of the wire part, press part, and dryer part of the paper machine when operated for 8 hours, on a 5-point scale. The state where no stain was generated in any part was set to 5, and the state where the stain was generated in any part and the operation could not be continued was set to 1. Normally, the number of continuous operations is 3 or more.

[Size] Size is measured according to JIS P81.
22 and evaluated by Stoeckigt sizing.
The Stoeckigt sizing degree of the above electrophotographic transfer paper was measured twice. After preparing the above sample, 20 ° C, 65% R
After humidity control for 3 hours under H atmosphere, measurement is performed once,
After humidity control for 2 hours, the measurement was performed again.

[Inkjet Suitability] With respect to the inkjet suitability, the print quality of characters printed using an inkjet printer BJ-10V manufactured by Canon Inc. was evaluated by visual evaluation in 6 levels. The case where there was no feathering was set as 6, and the case where the ink was bleeding and the characters could not be discriminated was set as 1. The print quality that can withstand normal use is 4 or more.

[Toner Fixability] The suitability for electrophotography was evaluated by the following method using a sample cut into A4 size grain length using an electrophotographic copying machine (SF-9400) manufactured by Sharp Corporation. . Commercially available 18 mm wide cellophane adhesive tape (Nichiban Co .; cellophane tape) was applied at a linear pressure of 300 g / cm to the image portion having an optical density of about 1.4, which was copied by the above copying machine, at a speed of 1 cm / sec. The ratio of the image density after peeling to the image density before peeling when peeled (hereinafter referred to as O
Evaluation was made by using (D ratio) as an index. The electrophotographic transfer paper is required to have toner fixability of OD ratio of 0.7 or more. A Macbeth reflection densitometer (Macbeth RD-918) was used to measure the image density.

[0064]

[Table 1]

Evaluation results: In Table 1, by comparing the electrophotographic transfer papers of Example 2 and Comparative Examples 1 to 3, in terms of sizing property, a sizing agent other than AKD was used as the internal size. As for the products, there is no change in the sizing property over time, and it can be seen that the sizing property is exhibited immediately after the papermaking. Therefore, the printing quality when printed by the inkjet printer does not change with time.

By further comparing the electrophotographic transfer papers of Example 2 and Comparative Examples 2 and 3, in the internally added sizing agent having a good rise in sizing property, α-
It can be seen that the best operability is obtained when a non-reactive emulsion size having a hydroxycarboxylic acid structure is used. However, when comparing the electrophotographic transfer papers of Examples 2, 9, and 10, it can be seen that the operability tends to deteriorate, although the sizing property increases as the amount of the sizing agent added increases.

By comparing the electrophotographic transfer papers of Examples 1 to 4 and Comparative Examples 4 and 5, a non-reactive emulsion sizing agent having an α-hydroxycarboxylic acid structure was used as the internal addition size of the base paper. In this case, a surface sizing agent having a composition of styrene / acrylic acid copolymer on the surface of the raw paper is 0.01 to
It can be seen that the 0.20 g / m ² coating improves the toner fixability when printed by the electrophotographic method and the print quality when printed by an inkjet printer.

By comparing the electrophotographic transfer papers of Examples 5 to 8 and Comparative Examples 4 and 6, even if the surface sizing agent having the composition of styrene / methacrylic acid copolymer was applied, It can be seen that the same effect as when applying a surface sizing agent having a composition of / acrylic acid type copolymer is obtained.

By comparing the electrophotographic transfer papers of Example 2 and Comparative Examples 7 and 8, the styrene / acrylic acid type copolymer and the styrene / methacrylic acid type copolymer described above were used as compositions. By applying a sizing agent other than the surface sizing agent to the base paper, the printing quality when printing with an inkjet printer is improved, but the toner fixability when printed with the electrophotographic method deteriorates.

[0070]

From the above evaluation results, the electrophotographic transfer paper of the present invention shows that the pulp slurry contains calcium carbonate as a filler and a non-reactive emulsion having an α-hydroxycarboxylic acid structure as a main component as an internally added sizing agent. By applying a styrene / acrylic acid type copolymer or a styrene / methacrylic acid type copolymer as a surface sizing agent to the surface of the base paper that has been made by adding a sizing agent to 0.01 to 0.20 g / m ² In addition, it has excellent characteristics that have both electrophotographic suitability and inkjet suitability.

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Claims (1)

[Claims] 1. A surface sizing agent on the surface of a base paper produced by adding calcium carbonate as a filler and a non-reactive emulsion sizing agent having an α-hydroxycarboxylic acid structure as a main component as an internally added sizing agent to a pulp slurry. A transfer paper for electrophotography, characterized by being coated with 0.01 to 0.20 g / m ^{2 of a} styrene / acrylic acid type copolymer or a styrene / methacrylic acid type copolymer.