JP2010249888A - Electrophotographic transfer paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrophotographic transfer paper which can suppress the occurrence of heat curling even when being heated by a copying machine or the like. <P>SOLUTION: The electrophotographic transfer paper has wood pulp as a main component. In this case, macerating of the electrophotographic transfer paper is carried out based on JISP8220, and the electrophotographic transfer paper is characterized by having 86.0% or less moisture in the pulp sheet after performing the suction filtration of the macerated pulp on a wire mesh. Furthermore, it is preferable that the number average fiber length of fibers in the macerated pulp is 0.37 mm or more and 0.43 mm or less, the density is 0.70 g/cm<SP>3</SP>or less, and the air resistance is 25 seconds or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an electrophotographic transfer sheet. Electrophotography is a photograph in which the surface of a photoconductive material is uniformly charged, and the electrostatic latent image generated by exposure is physically developed with colored fine particles to create a visible image on a support. An electrophotographic transfer sheet is a sheet used as a support on which a visible image is formed.
The present invention relates to an electrophotographic transfer paper suitable for such an electrophotographic support.

  Electrophotographic technology is widely applied to office copiers, etc. When transferring visible images with such office copiers, etc., after attaching toner corresponding to colored fine particles to the surface of transfer paper, The toner is fixed to the transfer paper by performing heat and pressure fixing between the pressure roll and the heating roll. Since the transfer paper is heated at the time of thermal pressure fixing, heat transfer and undulation phenomena occur on the transfer paper after transfer. However, when the degree of heat curl and undulation increases, the appearance deteriorates and office copying machines, etc. In this case, a paper running trouble is likely to occur.

  In order to prevent such heat curling and undulation, conventionally, the tree species of the chip, the fiber length of the pulp (degree of beating), fiber orientation, paper moisture and the like have been adjusted. However, in recent years, waste paper is also used for transfer paper, and when it becomes paper with a high waste paper blending ratio, it is difficult to adjust the tree species and beating degree to a desired state, and it is difficult to suppress heat curl and undulation. It has become.

In recent years, the following techniques have been developed as techniques for preventing heat curl (for example, Patent Documents 1 and 2).
The technology of Patent Document 1 adopts a gate roll coater method (GRC method) as a surface size press method, and applies a surface size press solution using an oxidized starch having an aldehyde group as a functional group as a glue solution to the surface of paper. This is a technique for preventing heat curling, and that the surface size press solution is as described above, the concentration of the surface size press solution is adjusted to 10 to 14% by weight, and the metering roll rotation ratio is 60 It is characterized by adjusting in a range of ˜80%.
The technique of Patent Document 2 is characterized in that when paper is divided into two layers, a front layer and a back layer, equally or almost equally, the difference in the dewatering freeness between each layer is adjusted to 30 ml or less. Technology.

  The technique of Patent Document 1 makes the paper layer in the thickness direction uniform by promoting the penetration of the starch solution to be coated into the paper layer, and the technique of Patent Document 2 reduces the difference in freeness between the front and back. In other words, it is intended to prevent heat curl with a focus on making the paper quality of the front and back sides uniform.

  Further, paying attention to the characteristics of the disaggregated pulp, proposals have been made to prevent the occurrence of curling and wrinkling in electrophotographic equipment and the like. In patent document 3 and patent document 4, it is proposed to make the water retention of the disaggregated pulp into a specific range. However, heat curls and undulations have not been sufficiently prevented.

JP 2002-348798 A Japanese Patent No. 3370737 Japanese Patent Laid-Open No. 9-119091 JP 2005-186573 A

  In view of the above circumstances, an object of the present invention is to provide an electrophotographic transfer paper capable of suppressing the occurrence of heat curl and undulation even when heated by a copying machine.

The first invention is an electrophotographic transfer paper mainly composed of wood pulp, wherein the electrophotographic transfer paper is disaggregated according to JISP8220, and the pulp sheet moisture after the disaggregated pulp is suction filtered on a wire mesh The electrophotographic transfer paper is characterized by being 86.0% or less.
A second invention is the electrophotographic transfer paper according to the first invention, wherein the number average fiber length of the separated pulp is 0.37 mm or more and 0.43 mm or less.
A third invention is the electrophotographic transfer paper according to the first or second invention, wherein the density is 0.70 g / cm ³ or less and the air resistance is 25 seconds or less.

  The electrophotographic transfer paper of the present invention has less moisture removed by the dryer of the paper machine, and the shrinkage of the paper by the dryer is reduced. Then, since the distortion and habit of the paper can be reduced, it is possible to suppress the occurrence of heat curl and undulation when heated by the copying machine.

The inventors of the present invention have completed the present invention as a result of diligent research on methods for preventing the occurrence of heat curling and undulation when electrophotographic transfer paper is heated by a copying machine.
The heat curl in the electrophotographic transfer paper becomes prominent when the paper shrinks due to moisture release and there is a difference in shrinkage between the front and back of the paper. Therefore, as a measure for preventing the occurrence of heat curl, there are a method of reducing the shrinkage of paper and a method of minimizing the difference between the front and back, but the present inventors remove them with a dryer of a paper machine at the time of manufacture. It was estimated that the amount of moisture had an effect on the occurrence of heat curl and undulation, and the pulp sheet moisture was measured by filtering the pulp suspension by a specific method. However, because the pulp sheet moisture measured with the raw material pulp may change during the paper manufacturing process, the relationship with the paper properties related to the problem to be solved by the present invention has not been clarified. Then, when the pulp sheet water | moisture content was measured for the pulp which disaggregated manufactured paper by the said method, the relationship with the heat curl and the wave which the present invention is going to solve became clear, and the present invention was completed.

  The electrophotographic transfer paper of the present invention is an electrophotographic transfer paper mainly composed of wood pulp. After the electrophotographic transfer paper is disaggregated in accordance with JISP8220, the disaggregated pulp is suction filtered on a wire mesh. The pulp sheet moisture is 86.0% or less. If it is higher than 86.0%, the expansion and contraction of the paper will increase, the heat curl will increase, and the undulation will increase rapidly.

The procedure for measuring the pulp sheet moisture used in the present invention is as follows. This measurement method assumes dewatering with a paper machine wire.
(1) Dissolve the electrophotographic transfer paper according to JISP8220: 1998 Pulp-Disaggregation method. The disaggregation conditions are as follows: solid content of dry sample 30 g, soaking time 4 hours before disaggregation, liquid amount 2000 ml at disaggregation, shaft rotation speed 30000 times.
(2) A 500 ml sample prepared to a pulp concentration of 1.0 ± 0.1% is prepared, and the temperature of the sample is set to 20.0 ± 0.5 ° C.
(3) The sample is transferred to a Buchner funnel (diameter 150 mm) on which a wire mesh is set, and immediately, suction by a vacuum pump is started. (Wire mesh: manufactured by Nippon Filcon Co., Ltd., 2.5 double weave, product name LL40E, suction pressure of vacuum pump: set to −0.012 MPa without sucking the sample by the leak valve)
(4) After the water on the wire mesh is drawn and the pulp sheet becomes white, the suction is continued for 5 seconds to stop the suction.
(5) The pulp sheet is peeled off from the wire mesh, and the pulp sheet moisture is determined by the following formula according to JISP8127: 1998 paper and paperboard-moisture test method-method using a dryer.
X = (m1-m2) / m1 × 100
Here, X: pulp sheet moisture (%), m1: mass of pulp sheet before drying,
m2: Mass of pulp sheet after drying

The measurement method will be described in more detail.
(Sample disaggregation)
The pulp sheet moisture in the electrophotographic transfer paper of the present invention is measured using a pulp suspension disaggregated by a disaggregation method based on JISP8220.
When preparing the pulp suspension, the time required for disaggregation varies depending on the components constituting the electrophotographic transfer paper, and is thus adjusted as appropriate depending on the electrophotographic transfer paper to be measured. When the electrophotographic transfer paper is disaggregated, the electrophotographic transfer paper is immersed in water for 4 hours and then disaggregated, and whether the disaggregation is visually determined from the fiber flock state is insufficient. If there is, the disaggregation time (the number of revolutions of the disaggregator) is added until disaggregation. However, since the test results are affected, the disaggregation time should not be excessive.

(Measurement concentration of sample)
The measured concentration of the sample is generally 1.0 ± 0.1% which is close to the concentration supplied to the wire of the paper machine.
(Concentration adjustment of sample)
The concentration of the sample can be adjusted to 1.0 ± 0.1% since the concentration of the disaggregated pulp is known. Industrial water is used for dilution.
(Sample temperature)
Since the temperature of the sample affects the measurement result, it is kept constant.
(Suction pressure)
The suction pressure is set to a constant value by a leak valve in advance before starting measurement. The suction pressure is preferably set with reference to the suction pressure of the suction box of the wire part of the paper machine. Note that it has been confirmed that the suction pressure hardly affects the sheet moisture in the range of -0.08 MPa to -0.20 MPa.
(Number of measurements)
The number of measurements is 3 or more, and the result is the average value.

Hereinafter, the electrophotographic transfer paper of the present invention will be described in detail.
(Pulp fiber)
The electrophotographic transfer paper of the present invention can use kraft pulp produced by chemically treating a lignocellulose material. Specifically, pulp produced by chemically treating hardwood bleached kraft pulp, softwood bleached kraft pulp, hardwood bleached sulfite pulp, softwood bleached sulfite pulp, and other fiber materials such as wood, cotton, hemp, and leather Can also be used.
As a bleaching method for these pulps, the possibility of generation of organochlorine compounds can be reduced, so that a bleaching method that does not use elemental chlorine (Elementaryly).
Chlorine Free (ECF) and a method of bleaching using ozone / hydrogen peroxide mainly without using chlorinated chemicals (Total Chlorine)
Free; TCF).

  Also, mechanical pulp obtained by mechanically pulping wood or chips can be used. Specifically, groundwood pulp, chemimechanical pulp mechanically pulped after soaking chemicals into wood and chips, and thermomechanical pulp pulped with refiner after chips are softened to some degree are used. it can.

  The electrophotographic transfer paper of the present invention may use only these virgin pulps, but preferably uses waste paper pulp. Waste paper pulp can make the pulp sheet moisture lower than virgin pulp, and from the viewpoint of effective use of resources, it is preferable to have a high blending ratio, and the blending ratio is 50% or more, more preferably 80% or more. preferable. As raw materials for waste paper pulp, unprinted waste paper such as cuts, damaged paper, widened white, special white, medium white, and white loss generated in bookbinding, printing factories, cutting offices, etc .; printed or copied High-quality printed paper such as high-quality paper, high-quality coated paper; old paper written with water-based ink, oil-based ink, pencil, etc .; newspapers including flyers such as printed high-quality paper, high-quality coated paper, medium-quality paper, medium-quality coated paper Waste paper; used paper such as medium-quality paper, medium-quality coated paper, and reprint paper can be blended. These are used only after disaggregation or after deinking as necessary.

Any of the above-mentioned pulps may be used in any combination, but preferably the freeness is adjusted to 200 ml or more and 500 ml or less.
The virgin pulp used is preferably hardwood bleached kraft pulp (LBKP) having a short fiber length and a thick wall thickness. Softwood bleached kraft pulp (NBKP) can also be mixed, but if the blending ratio of NBKP is too high, the texture becomes poor and undulation occurs, so it is preferable to make it 10% by weight or less of the total pulp amount.
Here, in the electrophotographic transfer paper of the present invention, it is desirable that the number average fiber length of the disaggregated pulp is 0.37 mm or more and 0.43 mm or less. As the average fiber length of the pulp, the weight average fiber length is often used, but since the pulp sheet moisture is strongly influenced by the fine fibers, the number average fiber length that can sensitively measure the amount of the fine fibers was evaluated. If the number average fiber length is less than 0.37 mm, heat curl may occur, which may cause dehydration failure in the wire part of the paper machine. When it is larger than 0.43 mm, the moisture of the pulp sheet becomes high and causes undulation. The number average fiber length varies greatly depending on the type of pulp used and the degree of pulp beating, but is also affected by the dewatering conditions of the wire part of the paper machine. That is, when the wire part is relatively strongly dehydrated, the fine fibers are removed from the wire, so that the number average fiber length is increased. However, if the gentle dehydration is performed, the fine fibers are difficult to be removed and the number average fiber length is reduced. In addition, the white paper water contains a large proportion of fine fibers, and the number average fiber length increases when a part of the white paper water is removed from the system.

(About control of pulp sheet moisture)
In the present invention, the pulp sheet moisture of the electrophotographic transfer paper is affected by the beating degree of the pulp used. In the case of softwood kraft pulp and hardwood kraft pulp, it is possible to lower the pulp sheet moisture by proceeding to some extent rather than unbeaten, but excessive beating increases the pulp sheet moisture. The beating degree of the pulp to be used is set to an optimal value so that the strength and smoothness of the electrophotographic transfer paper become a desired value in consideration of moisture of the pulp sheet.
Also, the pulp sheet moisture of the electrophotographic transfer paper is affected by the type of pulp. Waste paper pulp can make the pulp sheet moisture lower than virgin pulp.

In order to reduce pulp sheet moisture, the pulp fibers in a wet state can also be dried. Therefore, it is preferable to use dry pulp rather than slush pulp. Dry pulp refers to a product obtained by drying slush pulp (wet pulp obtained directly from the pulp manufacturing process) to a moisture content of about 25 to 3%.
Moreover, a pulp sheet water | moisture content can further be reduced by repeating the cycle of a wet state, a dry state, a wet state, and a dry state several times with respect to a pulp fiber.
In addition, the pulp sheet moisture of the electrophotographic transfer paper is also affected by the paper making conditions, and in particular, changes depending on the yield at the wire part, and is also affected by the addition conditions of the yield improver.

  In the electrophotographic transfer paper of the present invention, a filler can be added up to about 20% by mass in order to adjust the opacity, whiteness and surface properties. When the addition rate exceeds 20% by mass, the generation of paper dust becomes remarkable, and a paper jam occurs in an electrophotographic recording apparatus. The filler may not be added, but it is preferable to add it to prevent set-off and to ensure whiteness. From the viewpoint of curling prevention, the addition rate is preferably 3% by mass to 20% by mass for the purpose of reducing the stretching behavior between the fibers. The pulp sheet moisture can be lowered by adding a filler.

  Usable fillers are heavy calcium carbonate, light calcium carbonate, kaolin, calcined clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, aluminum silicate, calcium silicate, magnesium silicate, synthetic Examples include white inorganic pigments such as silica, aluminum hydroxide, alumina, sericite, white carbon, saponite, calcium montmorillonite, sodium montmorillonite, bentonite, and organic pigments such as acrylic plastic pigment, polyethylene, urea resin, etc. it can. When blending used paper, the ash contained in the used paper raw material can be used.

  By the way, in this invention, although the pulp sheet water | moisture content of the pulp which disaggregated the paper after papermaking is specified, it is also considered to measure a pulp sheet water | moisture content similarly with the pulp before papermaking. However, these two figures are different. The reason is that the raw material supplied to the paper machine loses pulp fibers and fillers when dewatering the wire part or pressing water in the press part. This is because there is a difference in composition. The present invention has been found that, by specifying the pulp sheet moisture of the pulp from which the paper has been disaggregated, it is possible to prevent the occurrence of heat curling and undulation, which are the problems of the present invention.

(Internal sizing agent)
It is preferable to use an internal sizing agent in the electrophotographic transfer paper of the present invention. Internal sizing agents include neutral rosin sizing agents, neutral rosin sizing agents, alkenyl succinic anhydride (ASA), alkyl ketene dimers (AKD), petroleum resin sizing agents, etc. Although the sizing agent used for papermaking can be used, it is not limited to these.

(Physical properties of electrophotographic transfer paper)
Basis weight of the electrophotographic transfer paper of the present invention is preferably, 60 g / m ² or more 128 g / m ² or less. More preferably, 60 g / m ² or more 100 g / m ² or less, further preferably 60 g / m ² or more 90 g / m ² or less. A higher basis weight is more advantageous for curling and corrugation, but if the basis weight exceeds 128 g / m ² , the paper is stiff and the paper runnability in the copying machine may be reduced. If it is lower than 60 g / m ^2, it is difficult to suppress the occurrence of heat curl and undulation, which is not preferable from the standpoint of set-off.
The density of the electrophotographic transfer paper of the present invention is preferably 0.70 g / cm ³ or less. This is a lower value than the conventional general electrophotographic transfer paper. In addition to specifying the moisture of the pulp sheet described above, the contact between the pulp fibers is reduced in this way, and the pulp fibers Since the expansion and contraction is suppressed from being propagated throughout the paper, heat curl can be suppressed. Further, the air resistance according to JISP 8117 of the electrophotographic transfer paper of the present invention is preferably 25 seconds or less. This is also generally lower than conventional electrophotographic transfer paper. In addition to specifying the moisture content of the pulp sheet described above, in this way, the heat dissipation of the electrophotographic transfer paper is improved and copying is performed. Occurrence of heat curl can be suppressed because less moisture is sometimes released.

(Surface treatment using surface coating solution)
The surface of the electrophotographic transfer paper of the present invention is preferably subjected to a surface treatment for applying a surface coating solution containing a surface sizing agent for the purpose of preventing surface fiber picking and improving the size.
Surface sizing agents include oxidized starch, phosphated starch, homemade modified starch, cationized starch or various modified starches, polyethylene oxide, polyacrylamide, sodium polyacrylate, sodium alginate, hydroxymethylcellulose, carboxymethylcellulose, methylcellulose, polyvinyl Alcohols, rosin-based sizing agents, synthetic sizing agents, petroleum resin-based sizing agents, or derivatives thereof can be used alone or in combination, but are not limited thereto.
The sizing degree is adjusted by the amount of the internal sizing agent and the surface sizing agent described above. The Steecht sizing degree of the electrophotographic transfer paper of the present invention is preferably from 2 seconds to 60 seconds.

Furthermore, for the purpose of imparting electrical conductivity to the surface of the paper, the surface coating solution contains inorganic substances such as sodium chloride, potassium chloride, sodium sulfate, zinc oxide, titanium dioxide, tin oxide, aluminum oxide, magnesium oxide, and alkylphosphoric acid. Organic materials such as ester acids, alkylsulfuric acid esters, sodium sulfonates, and quaternary ammonium salts can be used alone or in combination. The surface electrical resistivity of the electrophotographic transfer paper can be controlled by adjusting the blending amount of these conductive agents.
More specifically, the blending of these conductive agents can prevent troubles caused by static electricity when used in a copying machine or printer that uses an electrophotographic method. The surface electrical resistivity for this purpose is preferably in the range of 1 × 10 ⁸ to 1 × 10 ¹² Ω, more preferably 1 × 10 ⁹ to 1 × 10 ¹¹ Ω. In addition, this surface electrical resistivity can be measured by the method based on JISK6911 in the measurement environment prescribed | regulated to JISP8111 in the measurement environment prescribed | regulated to the sheet | seat (electrophotographic transfer paper) conditioned on the standard conditions based on JISP8111.

  In addition to the above, various auxiliary agents blended in ordinary coated paper paints such as a paper strength enhancer, a water retention agent, a dye, and a pH adjuster can be appropriately used for the surface coating solution.

  The surface coating solution containing the above components can be electrophotographic transfer paper by a commonly used coating means such as a size press, shim size, gate roll, roll coater, bar coater, air knife coater, rod blade coater, blade coater, etc. It can be applied to the surface of Thereafter, after a drying process, a smoothing process is performed with a calendar, and an electrophotographic transfer paper can be obtained.

  In order to produce the electrophotographic transfer paper of the present invention, as described above, the freeness of the raw pulp is adjusted to a preferred range, and the raw pulp is selected and beaten to identify the pulp sheet moisture. Is obtained. And a surface coating liquid is apply | coated to the surface, it dries and a calendar process is performed. Finally, it is cut and packaged to be finished as an electrophotographic transfer paper.

(Example)
The embodiments of the present invention are specifically shown by the following examples.
Example 1
As a raw material for pulp, 40% by weight of newspaper waste ink deinked pulp (250 ml CSF) and 60% by weight of high quality waste paper deinked pulp (400 ml CSF) were used to make an electrophotographic transfer paper using a long net on-top paper machine. The conditions for adding papermaking chemicals are as follows.
(Paper making chemical addition conditions)
The following chemicals were added on a dry basis per pulp. In addition, weight% is displayed by solid content or an active ingredient.
Light calcium carbonate (Okutama Kogyo Co., Ltd., trade name: Tamapearl 121-6S) 5% by weight, sulfate band (Maruzumi Engineering Co., Ltd.) 3% by weight, cationized starch (Matsuya Chemical Co., Ltd., trade name: Amylofax T2200) 0.5% by weight, internal sizing agent (Arakawa Chemical Industries, trade name: SPN-811M) 0.30% by weight
(Surface coating solution)
A surface coating solution in which 5.0% by weight of a surface sizing agent (Arakawa Chemical Industries, Ltd., trade name: Polymaron M20) is added to starch (Oji Cornstarch Co., Ltd., trade name: Oji Ace A) It apply | coated with the gate roll coater so that it might become 1.2 g / m < ² >.
The base paper was calendered to produce an electrophotographic transfer paper having a basis weight of 64.0 g / m ² and a reel moisture of 5.0%.

The produced electrophotographic transfer paper was disaggregated and the pulp sheet moisture and number average fiber length were measured. In addition, the density of the electrophotographic transfer paper, the air resistance, and the heat curl and undulation in the copying machine were evaluated. The results are shown in Table 1. Each evaluation method is as follows (freeness) JISP 8121: 1995 Pulp freeness test method Canadian standard freeness (pulp sheet moisture) Pulp sheet moisture was measured by the following procedure. The measurement was performed three times on the same sample and the average value was taken.
(1) Dissolve the electrophotographic transfer paper with industrial water according to JISP8220: 1998 Pulp-Disaggregation method. The disaggregation conditions are as follows: solid content of dry sample 30 g, soaking time 4 hours before disaggregation, liquid amount 2000 ml at disaggregation, shaft rotation speed 30000 times.
(2) Further, dilute with industrial water to prepare 500 ml of a sample prepared to a pulp concentration of 1.0 ± 0.1%, and set the temperature of the sample to 20.0 ± 0.5 ° C. using a thermostatic bath.
(3) The sample is transferred to a Buchner funnel (diameter 150 mm) on which a wire mesh is set, and immediately, suction by a vacuum pump is started. (Wire mesh: manufactured by Nippon Filcon Co., Ltd., 2.5 double weave, product name LL40E, vacuum pump: oil rotary vacuum pump manufactured by Sato Vacuum Machinery Co., Ltd., SW100 type, degree of vacuum 0.1 Pa, exhaust rate 100 liters / minute (The suction pressure is set to -0.012 MPa with a leak valve in a state where the sample is not sucked)
(4) After the water on the wire mesh is drawn and the pulp sheet becomes white, the suction is continued for 5 seconds and the suction is stopped.
(5) The pulp sheet is peeled off from the wire mesh, and the pulp sheet moisture is obtained by the following formula according to JISP8127: 1998 paper and paperboard-moisture test method-method using a dryer. The measurement was performed three times, and the result was the average value.
X = (m1-m2) / m1 × 100
Here, X: pulp sheet moisture (%), m1: mass of pulp sheet before drying,
m2: Mass of pulp sheet after drying (number average fiber length)
In the same manner as when the moisture of the pulp sheet was measured, the electrophotographic transfer paper was disaggregated and measured with a Kayani fiber length measuring device (trade name: FS-200, manufactured by Kayani).
(density)
JISP8118: 1998 "Paper and paperboard-Thickness and density test method" density (air permeability resistance)
JISP8117: 2009 "Paper and paperboard-Air permeability and air resistance test method (intermediate region)-Gurley method"
100 sheets of electrophotographic transfer paper were copied, and the curled and wavy state after copying was visually determined.
Curling evaluation A: Not curled B: Curled a little, but no problem in practical use X: Curld considerably and sometimes cylindrical.
Wavy evaluation A: No waviness is observed. O: There is a slight waviness, but there is no problem in practical use.

(Examples 2-6, Comparative Examples 1-4)
Except as shown in Table 1, an electrophotographic transfer paper was produced in the same manner as in Example 1. Table 1 shows the results of evaluation in the same manner as in Example 1.

From the results shown in Table 1, it can be seen that the electrophotographic transfer papers of Examples 1 to 6 in which the pulp sheet moisture of the disaggregated pulp is 86.0% or less are good in both curl evaluation and corrugation evaluation. Further, the number average fiber length is 0.37 mm or more and 0.43 mm or less, the density is 0.70 g / cm ³ or less, and the air resistance is 25 seconds or less.

On the other hand, compared with Example 2, Comparative Example 1 is an example in which LBKP uses slush pulp instead of dry pulp, and the pulp sheet moisture is 86.1%, which is higher than 85.5% of Example 2. The wavy evaluation is getting worse.
Compared with Example 4, Comparative Example 2 has the same pulp composition, but because the freeness of LBKP is high, the pulp sheet moisture is 86.1%, which is higher than 85.7% of Example 4, Evaluation is getting worse.
In Comparative Example 3, because the freeness of high-quality waste paper deinked pulp is low, the pulp sheet moisture is as high as 86.3%, and the number average fiber length is small, so both curl evaluation and wavy evaluation are poor.
In Comparative Example 4, since the blending ratio of LBKP is as high as 40% by weight and the freeness is as high as 470 ml CSF, the pulp sheet moisture is as high as 86.4%, and the curl evaluation is good but the wavy evaluation is poor.

  As described above, according to the electrophotographic transfer paper of the present invention, it is possible to provide an electrophotographic transfer paper that can suppress the occurrence of heat curl and undulation even when heated by a copying machine or the like.

Claims (3)

  It is an electrophotographic transfer paper mainly composed of wood pulp, and the pulp sheet moisture after the electrophotographic transfer paper is disaggregated according to JISP8220 and the disaggregated pulp is suction filtered on a wire mesh is 86.0% or less An electrophotographic transfer paper characterized by the above.   The electrophotographic transfer paper according to claim 1, wherein the number average fiber length of the disaggregated pulp is 0.37 mm or more and 0.43 mm or less. The electrophotographic transfer paper according to claim 1 or 2, wherein the density is 0.70 g / cm ³ or less and the air resistance is 25 seconds or less.