JP2005309154A - Transfer paper for electrophotography and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide non-coating type transfer paper for electrophotography provided with excellent toner transferability which can be printed by an electrophotographic type printer using dry type toner, a facsimile machine, a copying machine and an on-demand printer. <P>SOLUTION: In the transfer paper for electrophotography having no any coating layer mainly composed of pigments on its surface, weight average fiber length of pulp constituting the transfer paper is 0.50 mm to 0.70 mm and ash content in the paper is from 10% to 20%. Furthermore, the density of the transfer paper is ≥0.9/cm<SP>3</SP>, ten-point average roughness (Rz) of the surface is 10 μm to 20 μm and is provided with wet strength agent. Moreover, the manufacturing method is provided for the transfer paper for electrophotography with a calender process carried out between a metallic roll and another metallic roll. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic transfer paper and a method for producing the same. More specifically, the present invention relates to a non-coating type electrophotographic transfer paper that can be printed by an electrophotographic printer, a fax machine, a copying machine, an on-demand printing machine using dry toner and has excellent toner transferability. It is.

  Output by electrophotography is rapidly expanding due to the spread of printing from personal computers and on-demand printing.

  Up to now, the sublimation type thermal transfer system has been the leading high-quality output media, and it has been used in the field of medical image processing, etc. However, the high price and long print processing time are major problems Met.

  Recently, coupled with dramatic improvements in resolution and ink droplet miniaturization technology, the inkjet printing system is approaching the image quality of silver halide photography, and several photo systems are commercially available due to their low running costs. Has reached. However, although the inkjet method is inexpensive, the printing processing time is long, and the problem that it is not suitable for the purpose of obtaining a large number of copies with high image quality has not been solved.

  In contrast, the electrophotographic method, which is relatively inexpensive and has a short print processing time, is attracting attention not only as a conventional text-centric output but also as a full-color output method that emphasizes visuals. There is a high demand and high demand for on-demand printing that does not require as many copies as for commercial printing or that can include variable information. Among them, particularly for applications such as high-quality brochures, photo books, albums, or simple bookbinding covers and stitched photographs, there is a need for electrophotographic transfer paper that has a high volume feeling and a high-quality feeling on printed matter.

  Among copiers and printers that employ an electrophotographic system, high-quality full-color devices with high image reproducibility use four colors of toner to form images. Furthermore, in order to improve the gradation and resolution and obtain a higher definition image, the particle size of the toner is reduced to 6 to 10 μm, and the study of the particle reduction technology aiming at further image quality improvement Is still being tried. Naturally, the influence on the side of the transfer paper that finally gives and receives the toner image is also great. When a conventional transfer paper is printed with an electrophotographic full-color image forming apparatus, the surface layer voids such as pulp fibers constituting the transfer paper are large, so the toner falls into the gaps between the fibers when transferring or melting and fixing the toner. Therefore, in terms of image quality, there is a decrease in gradation, such as a decrease in density, mottle (fine shading unevenness in the image), and graininess (roughness in the image), and there is also a problem on the transfer paper side, which is the transfer material. It was.

  Furthermore, in recent years, electrophotographic printers with higher printing speed have been put into practical use, and the contact time between the toner image and the image receiving material has been shortened. Therefore, the design of the transfer paper that has been considered so far cannot be satisfied as a technology for further improving the transfer efficiency of the toner image and the print image quality. In particular, in the case of a non-coating type transfer paper that does not have a coating layer on the surface. The restrictions are getting stricter.

  As a technology to improve the transfer efficiency of toner images to transfer paper, the volume electrical resistance value, surface electrical resistance value, smoothness and porosity of transfer paper can be specified, and further improved by providing a coating layer. Attempts have been studied for a relatively long time and some have already been reported.

  For example, a method for improving the image quality by improving the toner transfer performance by increasing the smoothness of the surface of the paper (for example, Patent Document 1) has been adopted. Simple rules like density and density are not enough. Further, as a method paying attention to the void portion on the surface layer of the sheet, an information recording sheet (patent) that extracts a void portion having a circle-equivalent mean diameter of 10 μm or more from a binarized image obtained by an image analysis device and sets the void ratio to a specified value or less. Document 2) is disclosed, but the paper thickness is important only when leveling toner melted at the time of thermal fixing to the paper only by grasping the unevenness of the paper surface from a two-dimensional area point of view from the principle of measurement. It could not be said that the influence of the unevenness in the direction was fully evaluated.

On the other hand, for full-color image forming apparatuses, recording paper of a coated paper type (for example, Patent Document 3) in which a coating layer mainly composed of pigment is provided on the surface is the mainstream. If the strength and smoothness are increased, the writing property is inferior, and the texture is also far from a quality paper-like impression. Furthermore, because coated paper is expensive, it cannot be used in the same way as monochrome transfer paper, which is frequently used in offices and personal environments. It was necessary to change the form of paper, causing problems for user convenience and inventory management.
JP-A-5-341553 JP 2001-188378 A Japanese Patent No. 3464723

  An object of the present invention is an electrophotographic transfer of an uncoated paper type which can be printed by an electrophotographic printer, a fax machine, a copying machine, and an on-demand printing machine using dry toner and has excellent toner transferability. Provide paper.

  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, in the basis weight of 120g / m ² ~260g / m electrophotographic transfer paper ² without the coating layer mainly composed of pigment on the surface, the weight average fiber length of the pulp constituting the transfer sheet 0.50mm~ It is 0.70 mm, and the ash content in the paper is 10% to 20%.

Further, the transfer paper has a density of 0.9 g / cm ³ or more.

  Furthermore, the ten-point average roughness (Rz) of the surface of the transfer paper is 10 μm to 20 μm.

  In addition, the transfer paper contains a wet paper strength agent.

  Further, the present invention is a method for producing an electrophotographic transfer paper, wherein a calendar process is performed between a metal roll and a metal roll when the electrophotographic transfer paper is produced.

  As described above, the electrophotographic transfer paper of the present invention can be printed by an electrophotographic printer using a dry toner, a fax machine, a copier, and an on-demand printer, and has excellent toner transferability.

  Hereinafter, the electrophotographic transfer paper of the present invention will be described in detail.

  In the electrophotographic system, an original latent image is formed on a semiconductor material, and then a visible toner image is formed with toner. This toner image has a negative or positive charge, and is transferred onto a transfer paper having the opposite charge, or once transferred onto an intermediate transfer material and then transferred onto a transfer paper. There is. Toner is transferred to the transfer paper by the electrostatic force of the oppositely charged toner and the transfer paper, but in reality, the toner image on the semiconductor material or intermediate transfer body and the transfer paper are brought into close contact with each other by mechanical pressure. Also shows an important role. With the aim of higher image quality, the development of toner technology is progressing in the direction of miniaturization. As a result, the image layer for forming a toner image is also made thinner.

  In recent years, the printing speed has been increased more and more due to the tandem layout of the photosensitive device, and electrophotographic printing machines having more than 20 pages per minute and more than 50 pages have been put into practical use. For this reason, the contact time between the toner image and the image receiving material is further shortened, and the contact between the toner image and the transfer paper, that is, the adhesion of the transfer paper is increasingly important for improving the transfer efficiency of the toner. In addition, the small-diameter toner image laminated on the transfer paper is fixed by a hot-pressing process between the pressurizing / heating rolls to form a printed material. At this time, the toner particles are melted and pressed while the surface of the transfer paper is being melted. Will be leveled.

In the present invention, the fiber length of the pulp constituting the basis weight 120g / m ² ~260g / m ² of transfer paper for electrophotography without the coating layer and 0.50Mm～0.70Mm, paper ash content 10% When the toner image on the semiconductor material or intermediate transfer body and the image receiving material are brought into close contact with each other by mechanical pressure, the flexible and highly smooth transfer paper exhibits sufficient adhesion. Expresses stable toner transferability that has never been achieved before. Further, since the toner is excellent in melting, leveling and fixing in the heat fixing step, a high quality image can be obtained.

Transfer sheet for use in the present invention, the basis weight of ^{120g / m 2 ~260g / m 2} . When the fiber length of the pulp is 0.50 mm to 0.70 mm and the ash content in the paper is 10% to 20%, if the basis weight of the transfer paper is less than 120 g / m ² , a high-class high volume feeling desired in the present invention Characteristics such as texture, paperiness and hand feeling that are full of feeling cannot be obtained. On the other hand, if it exceeds 260 g / m ² , the rigidity of the transfer paper is increased, the transportability in the printing device is lowered, paper jam occurs, and the heat capacity increases, resulting in insufficient heat fixing ability of the toner. A problem occurs. Similarly, when it is used for a part or all of a booklet or a book, problems such as a crack during processing and a sense of incongruity due to re-expansion of rigidity occur.

  In order to secure adhesion as a transfer paper and obtain an excellent image, the fiber length of the pulp needs to be 0.50 mm to 0.70 mm, and if it exceeds 0.70 mm, the surface property of the transfer paper deteriorates. Therefore, the transferability of toner particles is poor, and a uniform surface layer cannot be formed even after leveling after melting, so that sufficient image quality cannot be obtained. On the other hand, if it is less than 0.50 mm, the image quality is generally good, but a toner blister may be generated depending on the conditions of the printing device and the print image. Here, the toner blister is a defect in which voids in the laminated toner layer and air existing at the interface between the toner layer and the transfer paper are expanded when the toner is heated and melted, and the toner film is ruptured on the transfer paper surface. say. This expanded air should be released by taking advantage of the roughness and air permeability of the surface of the transfer paper, but it is considered that it breaks the molten toner layer due to the characteristics of the transfer paper that closes the passage. Yes. In addition, it becomes difficult to make paper stably because the strength in the wet paper state decreases, and when it becomes a transfer paper, the paper wrinkles deteriorate and the transportability and runnability in the equipment may be hindered. Curling after printing becomes a problem. In addition, the weight average fiber length here is measured with a pulp fiber length measuring device Kajaani FS-200 (manufactured by Metso).

  Further, in the transfer paper of the present invention, the ash content in the paper needs to be 10% to 20%. If it is less than 10%, the transfer paper is so stiff that adhesion within the device cannot be ensured, and it is difficult to be smoothed by the calendar process, and there are many gaps between fibers on the transfer paper surface, resulting in high-quality images. I can't hope. On the other hand, if the ash content exceeds 20%, it will fall within the desired range in terms of rigidity and surface properties, but ash content such as filler will easily fall off as it is transported in the equipment, and it will become paper dust and contaminate the equipment. This may cause image defects, or hinder the transfer and transportability of the transfer paper.

The transfer paper of the present invention is desired to have a transfer paper density of 0.9 g / cm ³ or more in order to improve the adhesion of the transfer paper and the thermal conductivity in the thermal pressure process. If it is less than 0.9 g / cm ^3, a transfer paper having a basis weight of 120g / m ² ~260g / m ² as in the present invention, the amount of heat given from the heating roll is fully fusing the toner particles in a short time Cannot be done.

  Furthermore, in the transfer paper of the present invention, the ten-point average roughness (Rz) representing the average value of fine irregularities on the surface of the transfer paper is desirably 10 μm to 20 μm. When the ten-point average roughness (Rz) is smaller than 10 μm, the air passage in which the air present in the stacked toner layers is to be released along the transfer paper surface layer is closed, and toner blisters are generated. . If the thickness exceeds 20 μm, there is no problem with the toner blister, but the surface property of the transfer paper is lowered, so that the transferability of the toner is lowered, and fine unevenness of the image and roughness of the image are conspicuous. High-quality images cannot be reproduced. The 10-point average roughness (Rz) referred to here is based on JIS B0601 (1994). Specifically, using a three-dimensional surface roughness meter manufactured by Kosaka Laboratory, a reference length of 2.5 mm, It is a measured value obtained with an evaluation length of 12.5 mm. Ten-point average roughness (Rz) was calculated as the sum of the average value of the absolute values of the altitude from the highest peak of the mountain valley to the fifth and the average value of the absolute values of the altitude from the lowest valley bottom to the fifth. Therefore, it is suitable for estimating the degree of coverage of the transfer paper surface by leveling of the molten toner, and the arithmetic average roughness (Ra) indicating the average roughness of the peaks and valleys in the entire measurement section and the specific size of the peaks and valleys. It is different from the maximum height (Ry) that also reflects.

In producing the transfer paper of the present invention, it is desirable to contain a wet paper strength agent. In order to maintain the adhesion and surface roughness of the transfer paper at a high level, the fiber length of the pulp used is 0.50 mm to 0.70 mm, and the ash content in the paper is 10% to 20%. The strength of the web in a damp state on the paper machine decreases. Especially if the basis weight increased to ^{120g / m 2 ~260g / m 2} , and reduce the production speed of the paper machine is high risk of web breaks due to the web of its own weight, stable and continuous production is extremely difficult It becomes. In this case, it is effective to include a wet paper strength agent that requires a certain amount of paper strength enhancing action even in a wet state.

  Further, in the production of the transfer paper of the present invention, calendar processing can be performed by an on-machine calendar facility or an off-line calendar facility provided on the paper machine, but processing between a metal roll and a metal roll is desirable. When calendering is performed between the metal roll and the metal roll, the weight applied to the calendering device effectively acts between the nips of the metal roll that maintains a narrow nip width even when the load is high. Uneven variation is eliminated. In contrast, if a resin belt such as a resin roll or a long nip calender is used on the image forming surface of the transfer paper, or if a calender such as a resin roll or a combination of heated metal rolls facing the resin belt is used, the same Compared with calendering with a metal roll-metal roll to which the total load is added, the nip width of the calender nip is widened and the additional load is dispersed, and the uneven thickness of the transfer paper that appears in a relatively long wavelength cycle is Since the correction is not corrected, the result is inferior to the adhesion and thermal fixing properties of the transfer paper, which is insufficient as a high-grade electrophotographic transfer paper, and a calender treatment between the metal roll and the metal roll is necessary.

  As the raw material of the pulp referred to in the present invention, conventionally known chemical pulps such as LBKP (hardwood bleached kraft pulp), NBKP (softwood bleached kraft pulp), LBSP (hardwood bleached sulfite pulp), NBSP (coniferous bleached sulfite pulp), etc. Any of these can be used. Furthermore, various types of mechanical pulp such as waste paper pulp, GP (Grand Pulp) and TMP (Thermomechanical Pulp), as well as non-wood pulp and synthetic pulp, do not impair the characteristics and high-quality image reproducibility of transfer paper. Although it can be used in combination, it is desirable to use virgin pulp with high whiteness and almost no foreign matter for the purpose of obtaining high-quality image reproducibility.

  In the present invention, examples of the internal filler that can be used include calcium carbonate, magnesium carbonate, kaolin, delaminated kaolin, calcined kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, Satin white, aluminum silicate, diatomaceous earth, calcium silicate, synthetic amorphous silica, colloidal silica, colloidal silica modified with cation, aluminum hydroxide, alumina, alumina hydrate, lithopone, zeolite, hydrohalosite, magnesium hydroxide, etc. White inorganic pigments, organic pigments, and the like. These fillers are added so that the ash content in paper according to JIS P8125 is 10 to 20% by mass.

  Examples of the internally added sizing agent used in producing the electrophotographic transfer paper of the present invention include rosin sizing agent in the case of acidic papermaking, alkyl ketene dimer, alkenyl anhydride succinic acid in the case of neutral papermaking. Examples include acids, neutral rosin sizing agents, cationic styrene acrylics, higher fatty acid salts, and paraffin wax.

  In the stock used for producing the electrophotographic transfer paper of the present invention, other various yield improvers and anionic properties that have been used conventionally are within the range that does not impair the desired effects of the present invention. In addition, a papermaking internal additive such as a nonionic, cationic or amphoteric freeness improver or paper strength improver may be appropriately selected and used as necessary. For example, various types of starch, polyacrylamide, polyethyleneimine, polyamine, polyvinylamine, polyamide / polyamine, urea formalin resin, melamine formalin resin, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, polyamide resin The above is used in combination as appropriate. Furthermore, a fixing agent such as a sulfuric acid band and aluminum chloride, a dye, a fluorescent dye, a slime control agent, and an antifoaming agent can be used.

  On the surface of the electrophotographic transfer paper of the present invention, oxidized starch, etherified starch, esterified starch, cationic starch, phosphate starch, modified starch such as phosphate esterified starch, modified starch, casein, binders such as polyvinyl alcohol, Surface sizing agent such as styrene / acrylic acid copolymer, styrene / methacrylic acid copolymer, acrylonitrile / vinyl formal / acrylic acid ester copolymer, styrene / maleic acid copolymer, ethylene-urea resin, etc. Of course, it is possible to size-treat the dimension stabilizer, inorganic conductive agent such as sodium chloride and potassium chloride, organic conductive agent, surfactant, pigment and dye.

  As a device for adding the binder and the surface sizing agent, a conventional size press, a gate roll size press, or a metade film transfer type size press, a rod coater, a bill blade coater, a short dwell coater, a blade coater, an air knife coater. A curtain coater or the like can be preferably used.

  In the papermaking method of the electrophotographic transfer paper of the present invention, the paper machine can be a paper machine known in the paper industry such as a long paper machine, a twin wire paper machine, a combination paper machine, a round paper machine, a Yankee paper machine, etc. .

  The electrophotographic transfer paper in the present invention is not limited to use as a dry electrophotographic transfer paper for an output device such as a copy, a printer, an on-demand printer, a fax machine, a wet electrophotographic transfer paper, an offset printing paper, It can be used as gravure printing paper and thermal transfer image receiving paper. It is also possible to apply a pressure-sensitive adhesive layer on the surface opposite to the printing application and apply it to the label application.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. Further, “%” shown in the examples represents mass% unless otherwise specified.

(Example 1)
The pulp mixed so that LBKP was 85% and NBKP was 15% was beaten to obtain a raw material pulp slurry having a weight average fiber length of 0.50 mm. Light calcium carbonate was added to the raw pulp slurry so that the ash content in the paper was 20%. Further, 1.1% cationized starch as a dry paper strength agent, 0.2% polyamide polyamine epichlorohydrin resin as a wet strength agent, A papermaking raw material was prepared by adding 0.15% of alkyl ketene dimer sizing agent and polyacrylamide type retention aid to improve yield and freeness. This paper raw material was introduced into a long paper machine to make a basis weight of 210 g / m ^2, and then oxidized starch 6.0%, styrene acrylic surface sizing agent 0.2%, salt 0.3%, A size press treatment was performed with a surface size press solution composed of 0.05% fluorescent whitening agent and 93.45% water, and then a calendar treatment was performed by an on-machine calendar facility having a metal roll-metal roll. Paper was manufactured.

(Example 2)
A transfer paper of Example 2 was produced in the same manner as in Example 1 except that light calcium carbonate was prepared so that the ash content in the paper was 10%.

(Example 3)
A transfer paper of Example 3 was produced in the same manner as in Example 1 except that a raw pulp slurry having a weight average fiber length of 0.70 mm after beating of the mixed pulp was used.

Example 4
A transfer paper of Example 4 was produced in the same manner as in Example 3 except that light calcium carbonate was added so that the ash content in the paper was 10%.

(Example 5)
Example 5 A transfer paper of Example 5 was produced in the same manner as in Example 1 except that the additional load of calendar processing by an on-machine calendar facility having a metal roll-metal roll was reduced.

(Example 6)
Example 6 A transfer paper of Example 6 was produced in the same manner as in Example 1 except that the additional weight of the calendar process by the on-machine calendar facility having a metal roll-metal roll was further reduced as compared with Example 5.

(Example 7)
A transfer paper of Example 7 was produced in the same manner as in Example 1 except that the transfer paper was made to have a basis weight of 120 g / m ² .

(Example 8)
A transfer paper of Example 8 was produced in the same manner as in Example 4 except that the transfer paper was made to have a basis weight of 120 g / m ² .

Example 9
A transfer paper of Example 9 was produced in the same manner as in Example 1 except that the transfer paper was made to have a basis weight of 260 g / m ² .

(Example 10)
A transfer paper of Example 10 was produced in the same manner as in Example 4 except that the transfer paper was made to have a basis weight of 260 g / m ² .

(Example 11)
Except for not using the polyamide polyamine epichlorohydrin resin that is a wet strength agent, the paper raw material prepared in the same manner as in Example 1 is led to a long net paper machine, and various operating conditions are adjusted so that the basis weight is 210 g / m ^2. Thus, a transfer paper of Example 11 was obtained. However, since the strength of the web on the paper machine was not sufficient, paper breakage often occurred during production, which was one step inferior in terms of production stability.

(Example 12)
Example 12 is the same as Example 1 except that the on-machine calendar facility having a metal roll-metal roll is replaced with a calendar treatment having a resin roll-heated metal roll (roll temperature 150 ° C.). A transfer paper was produced.

(Example 13)
Metal rolls-Instead of on-machine calender equipment with metal rolls, resin belt roll (shoe width 200 mm) equipped with a pressure shoe mechanism that realizes a long nip-calender treatment with calender equipment with heated metal roll (roll temperature 150 ° C) A transfer paper of Example 13 was produced in the same manner as Example 1 except that the above was performed.

(Comparative Examples 1-2)
The transfer paper of Comparative Example 1 was prepared in the same manner as in Example 1 except that the transfer paper was made to have a basis weight of 114 g / m ^2, and the transfer paper was made to have a basis weight of 265 g / m ^2. In the same manner as in Example 1, a transfer paper of Comparative Example 2 was produced.

(Comparative Examples 3-4)
The transfer paper of Comparative Example 3 was used in the same manner as in Example 1 except that the raw pulp slurry having a weight average fiber length of 0.44 mm after beating the mixed pulp was used, and the weight average fiber after beating the mixed pulp. A transfer paper of Comparative Example 4 was produced in the same manner as in Example 1 except that the raw material pulp slurry having a length of 0.75 mm was used.

(Comparative Examples 5-6)
The transfer paper of Comparative Example 5 was added in the same manner as in Example 1 except that light calcium carbonate was added so that the ash content in the paper was 7%, and light calcium carbonate was added so that the ash content in the paper was 25%. In the same manner as in Example 1, a transfer paper of Comparative Example 6 was produced.

  With respect to the electrophotographic transfer papers of Examples 1 to 13 and Comparative Examples 1 to 6 manufactured as described above, ten-point average roughness (Rz), image unevenness, texture and hand feeling, transportability in the printing press are measured by the following measurement methods. The amount of paper dust generated was measured. The evaluation results are shown in Tables 1 and 2.

1) Ten point average roughness (Rz)
Using a stylus type three-dimensional surface roughness meter manufactured by Kosaka Laboratory, measurement was performed under the conditions of a reference length of 2.5 mm and an evaluation length of 12.5 mm. In addition, an evaluation result is the average value which measured 8 places.

2) Image irregularity Canon: A solid image of black, cyan, magenta, and yellow was printed by passing through a blank sample of A4 length on a CP-2150 machine. The printing unevenness of the image was visually evaluated in the following five stages. A high-quality printed product requires an evaluation of 3 or more.
“5”: There is no image unevenness in each color.
“4”: Image unevenness is slightly observed in some colors.
“3”: Slight image unevenness is observed with two or more colors.
“2”: Image unevenness is partially observed for each color.
“1”: The entire image is uneven for each color.

3) Print image quality Canon: A CP-2150 machine was used to print an image for evaluation combining scenery and a person, and whether or not gloss feeling etc. felt as a glossy high-quality printed material was evaluated in the following five levels. A high-quality printed product requires an evaluation of 3 or more.
“5”: The printed portion is excellent in gloss and feels like a printed material close to a photographic paper photograph.
“4”: The printed portion has a high gloss feeling, and it can be felt as a magnificent printed matter that approaches art paper.
“3”: The printed portion has a glossy feeling, and feels smooth and elegant printed matter like coated paper.
“2”: The printed portion has low gloss and feels like a matte printed matter.
“1”: Roughness is recognized in the printed portion, and the texture of the image is not expressed well.

3) Volume feeling A printed matter on which an evaluation image was printed was created, and the texture and hand feeling of the printed matter were touched to evaluate whether or not it felt as a high-quality printed matter with a volume feeling. A high-quality printed product requires an evaluation of 3 or more.
“5”: With a touch full of volume, it has a heavy hand feeling that can be used for photo albums, albums, albums, etc.
“4”: With a high volume feeling, it has a solid hand feeling that can be used for brochures and catalogs mainly composed of photographs.
“3”: A sense of volume is felt, and there is a hand feeling that is used for book binding photos and magazine covers.
“2”: Inferior in volume, and a hand feeling similar to that of normal high-quality copy paper.
“1”: Poor volume feeling and poor hand feeling unsuitable as a high-quality printed matter.

4) In-printer transportability and paper dust Canon: Printed 200 sheets of A4-size transfer paper with a CP-2150 machine, paper jams in the machine at the time of printing, and paper dust adhered to the machine after printing The amount was comprehensively evaluated on a 5-point scale. If the evaluation is 3 or more, it can be said to be a practical level.
“5”: No paper jam, no paper dust is observed, and no trouble occurs.
“4”: No paper jam, paper dust is slightly observed, but no trouble occurs.
“3”: The number of paper jams is 2 or less, the amount of paper dust is small, and there is no fear of frequent troubles.
“2”: There is a concern that 3 to 9 paper jams occur or the amount of paper dust is large and has an adverse effect.
“1”: There is a great concern that paper jams frequently occur and the amount of paper dust is large and trouble frequently occurs.

5) Production stability In the production of transfer paper using a paper machine, production was carried out while appropriately adjusting and monitoring various operating conditions, and the operational stability at that time was evaluated in five stages. If the evaluation is 2 or less, it is not at a commercial practical level, and it is difficult to continue production stably while maintaining the quality of the transfer paper above a certain level.
“5”: The state of the web on the paper machine is stable, and it can be stably produced without any problem under normal production conditions.
“4”: The web on the paper machine is generally stable and can be manufactured stably by adjusting the operating conditions.
“3”: The web on the paper machine is somewhat unstable, but can be manufactured by adjusting the operating conditions.
“2”: The state of the paper web on the paper machine is unstable, and paper breaks often occur even when the operating conditions are adjusted.
“1”: The strength of the web on the paper machine is low, it is difficult to respond by adjusting the operating conditions, and paper breaks frequently occur.

Rating:
In Examples 1 to 5 and Examples 7 to 11, the basis weight, the weight average fiber length, and the ash content in the paper are in the range of the present invention, and the ten-point average roughness (Rz) and density of the transfer paper are the present invention. Meet the conditions. The print image quality of these transfer papers is high, satisfying the impression of high-quality printed matter, and there are no problems in production, and the result is balanced. Here, in Example 6 in which the calendar process was reduced and the density of the transfer paper was less than 0.9 g / cm ³ , although the print image quality was lowered and there was no problem in practical use, it was slightly in terms of the impression that it was a high-quality printed matter. The result was inferior. In addition, in Examples 12 to 13 in which the roll to be calendered was changed from a metal roll-metal roll to a resin roll-heated metal roll or a resin belt roll-heated metal roll, there is no practical problem in terms of printing image quality. The impression of high-quality printed matter was inferior to the case of using a metal roll-metal roll. Furthermore, in Example 11 in which the wet strength agent was not used, the quality of the transfer paper was not greatly affected, but the production stability on the paper machine was also a problem. On the other hand, in Comparative Examples 1 to 6, the basis weight, the weight average fiber length, or the amount of ash content in the paper is outside the scope of the present invention, but the printed image is uneven and practically problematic. The print quality is low and the impression of the printed material is not felt as a high-quality printed material, or even if the image quality is high, the toner blister is used at the same time. However, the transfer paper desired by the present invention could not be obtained.

  It can be used as electrophotographic transfer paper in various printing areas.

Claims (5)

In a basis weight 120g / m ² ~260g / m electrophotographic transfer paper ² without the coating layer mainly composed of pigment on the surface, the weight average fiber length of the pulp constituting the transfer sheet 0.50Mm～0. An electrophotographic transfer paper having a thickness of 70 mm and an ash content in the paper of 10% to 20%. 2. The electrophotographic transfer paper according to claim 1, wherein the density of the transfer paper is 0.9 g / cm ³ or more.   3. The electrophotographic transfer paper according to claim 1, wherein the ten-point average roughness (Rz) of the surface of the transfer paper is 10 μm to 20 μm.   The electrophotographic transfer paper according to any one of claims 1 to 3, wherein the transfer paper contains a wet paper strength agent.   5. The electrophotographic transfer paper according to claim 1, wherein a calendar process is performed between the metal roll and the metal roll.