JP2006058403A - Electrophotographic transfer sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic transfer sheet of a polyolefin resin film laminating type capable of stably obtaining excellent images at all times without being affected by kinds of machines of a printer or a printing environment. <P>SOLUTION: In the electrophotographic transfer sheet made by disposing a polyolefin resin film layer on at least one surface of a heat resistant sheet, surface resistivity of the electrophotographic transfer sheet is 1×10<SP>7</SP>to 1×10<SP>13</SP>Ω/sq. and the volume resistivity is 1×10<SP>8</SP>to 1×10<SP>14</SP>Ωcm. The polyolefin resin film is preferably a film obtained by uniaxial stretching or biaxial stretching, which contains pigments and antistatic agents as ingredients. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic transfer sheet that is excellent in durability and water resistance, and can always stably obtain a good image without being affected by the printing environment such as the printer model and humidity.

  Synthetic paper mainly composed of polypropylene and pigment (for example, “Yupo” manufactured by YUPO Corporation; see Patent Documents 1 and 2) is more durable and water-resistant than ordinary paper mainly made of pulp. It is used for documents, drawings, photographs, maps, manuals, labels, tags, etc. that are used in harsh environments such as high humidity, chemical exposure, and outdoors.

  For printing this synthetic paper, printing methods such as offset printing and screen printing have been used. However, in this case, since a plate making process is required, it is not suitable for printing a small number of copies in terms of cost. is there. The electrophotographic method can print directly on media without making digital information, so it is ideal for printing a small number of copies and variable information printing (variable printing). It has grown rapidly as an on-demand printing method in recent years. When used as media, the surface temperature of the heat roll during toner fixing exceeds the melting point of polypropylene, which is the main raw material for synthetic paper. There was a problem in running performance, such as the synthetic paper melted and cut off.

  In order to solve the problem caused by this heat resistance failure, a laminate in which a thermoplastic film layer such as synthetic paper is bonded to a heat resistant core material made of a paper base material or a thermoplastic polyester resin film is used as a medium. It has been proposed. (For example, see Patent Document 2)

However, as a result of printing by the present inventors in various environments using various printers for the laminate, it has been found that it is still insufficient. That is, in Patent Document 2, an antistatic agent is applied to the surface of the laminate and the surface electrical resistance value is adjusted in the range of 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ has good performance. However, depending on the model of the electrophotographic printer, the toner transfer efficiency from the secondary transfer belt to the paper may be reduced or temporarily transferred to the paper. In some cases, the toner comes off again, and this phenomenon was found to be particularly noticeable when printing under low humidity.

Japanese Examined Patent Publication No. 46-40794 JP 2002-258509 A

  As a result of intensive studies in view of the present situation, the present inventors have used a laminated sheet of a polyolefin-based resin film such as synthetic paper and a heat-resistant sheet as a transfer sheet for dry electrophotography, which affects the printer model and printing environment. In order to always obtain a good and stable image, it is found that not only the surface electrical resistance value but also the volume electrical resistance value is an important factor, and both the surface electrical resistance value and the volume electrical resistance value are In order to adjust well to the intended range, the inventors have found that means for incorporating an antistatic agent into the polyolefin resin film itself is the most effective and have completed the present invention.

(1) The present invention provides an electrophotographic transfer sheet in which a polyolefin-based resin film layer is provided on at least one surface of a heat resistant sheet, and the electrophotographic transfer sheet has a surface electrical resistance value of 1 × 10 ⁷ to 1. The electrophotographic transfer sheet is characterized in that it has × 10 ¹³ Ω / □ and a volume electric resistance value of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm.
(2) An electrophotographic transfer sheet, wherein a polyolefin resin film layer is provided on at least one surface of a heat-resistant sheet, and further a toner receiving layer is provided on the surface of the polyolefin resin film layer. The electrophotographic transfer sheet, wherein the sheet has a surface electric resistance value of 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □ and a volume electric resistance value of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm. .
(3) The polyolefin resin film according to any one of (1) to (2), wherein the polyolefin-based resin film contains a pigment and an antistatic agent as components and is obtained by uniaxial stretching or biaxial stretching. Transfer sheet for electrophotography.
(4) The electrophotographic transfer according to any one of (1) to (3), wherein a value obtained by dividing the volume electric resistance value by the surface electric resistance value (VR / SR) is 10 ⁻⁵ to 10 ^5. Sheet.
(5) The transfer sheet for electrophotography according to (2), wherein the toner-receiving layer contains a conductive metal oxide.

  The electrophotographic transfer sheet according to the present invention is excellent in durability and water resistance, and is not affected by the printing environment such as the printer model and humidity, and can always stably obtain a good image. It is extremely useful in practice.

In the present invention, since a laminated sheet of a polyolefin resin film and a heat-resistant sheet is used, there is no problem of running performance in a printer like a single sheet of a polyolefin resin film. Since the resistance value (SR) is set to 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □ and the volume electrical resistance value (VR) is set to 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm, A stable and good image can always be obtained without being affected by the printer model or printing environment. Among these, a value (VR / SR) obtained by dividing the volume electric resistance value by the surface electric resistance value (VR / SR) is preferably 10 ⁻⁵ to 10 ⁵ , and is preferable.

Incidentally, if the surface electrical resistance value is less than 1 × 10 ⁷ Ω / □, depending on the printer model, paper contact with a conductive printer member such as a static elimination brush may occur during toner transfer, and grounding will occur at that time. As a result, the current flows beyond the allowable range, and as a result, the potential difference between the photosensitive member (or the secondary transfer member) and the sheet is reduced to a level that adversely affects toner transfer, and an image defect occurs at the rear end in the printing direction. (The rear edge of the print is defective). On the other hand, if the surface electrical resistance value exceeds 1 × 10 ¹³ Ω / □, the toner charge remains excessively on the paper without escaping in the high print density area, so that the photoconductor (or secondary transfer body) and the paper The potential difference between them decreases to a level that adversely affects toner transfer, and toner transfer failure may occur depending on the printer model (high print density portion failure). Further, when the volume electric resistance value is less than 1 × 10 ⁸ Ω · cm, the charge of the toner transferred onto the paper quickly moves to the paper in the low print density portion, and the toner is in a polarized state, resulting in the result. Due to the Coulomb force between the photosensitive member (or the secondary transfer member) and the toner, the toner is easily detached from the sheet, and a transfer defect occurs at a low print density portion (low print density portion defect). On the other hand, when the volume electrical resistance value exceeds 1 × 10 ¹⁴ Ω · cm, the toner charge remains excessively on the paper without escaping, so that the potential difference between the photosensitive member (or the secondary transfer member) and the paper is the toner. Depending on the printer model, toner transfer failure may occur. Further, when the value obtained by dividing the volume electric resistance value by the surface electric resistance value (VR / SR) is less than 10 ⁻⁵ or exceeds 10 ⁵ , toner transfer may not be sufficient.

Moreover, as a result of examining the method for adjusting the electric resistance value, as described in JP-A-2002-258509, a means for applying an antistatic agent to the surface of the polyolefin resin film forming the laminate is used. When the surface electrical resistance value is adjusted to the range of 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □, the electrical resistance value of the film portion does not decrease but only the electrical resistance value of the surface layer decreases. It was found that it was difficult to adjust the volume electrical resistance value of the transfer sheet to a range of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm. On the other hand, when adjusting the surface electrical resistance value by adding an antistatic agent to the polyolefin resin film itself, the volumetric electrical resistance value of the electrophotographic transfer sheet is set to be uniform because the electrical resistance value in the thickness direction becomes uniform. It was found that it can be adjusted relatively easily in the range of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm.

  Examples of the polyolefin resin film used in the present invention include ethylene resins such as high density polyethylene and medium density polyethylene, propylene resins, polymethyl-1-pentene, and ethylene-cyclic olefin copolymers. Among these, it is preferable to use a propylene-based resin from the viewpoints of heat resistance, chemical resistance, and cost. Examples of the propylene-based resin include isotactic polymers or syndiotactic polymers obtained by homopolymerizing propylene. In addition, a copolymer based on propylene having various stereoregularities obtained by copolymerizing propylene with an α-olefin such as ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, etc. is used. You can also The copolymer may be a binary system, a ternary system or a multi-element system, and may be a random copolymer or a block copolymer. The propylene-based resin is preferably used by blending 2 to 25% by mass of a resin having a melting point lower than that of the propylene homopolymer. Examples of the resin having a low melting point include high-density or low-density polyethylene. As the polyolefin resin, one of the above polyolefin resins may be selected and used alone, or two or more may be selected and used in combination.

  If necessary, pigments, antistatic agents, stabilizers, light stabilizers, dispersants, lubricants and the like can be added to the polyolefin resin. Among them, a system to which a pigment and an antistatic agent are added is particularly preferable because it has features such as easy adjustment of the electric resistance value and good appearance of the sheet. Examples of the pigment include inorganic pigments and organic pigments. The pigment particle diameter is preferably 0.01 to 5 μm. As the inorganic pigment, for example, heavy calcium carbonate, light calcium carbonate, calcined clay, silica, talc, titanium oxide, barium sulfate, alumina and the like can be used. Examples of the organic pigment include polymers such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon-6, nylon-6,6, cyclic olefin, polystyrene, polymethacrylate, and the like. A polymer having a glass transition temperature can be used. One inorganic pigment and / or organic pigment may be selected and used alone, or two or more may be selected and used in combination. The pigment is usually added in the range of 3 to 50% by mass.

Examples of the antistatic agent include organic antistatic agents such as sorbitan fatty acid ester, glycerin monooleate, polyethyleneimine, poly (ethyleneimine-urea), water-soluble quaternary cationic polyacrylate, polyaniline, and polyethylene glycol; Inorganic antistatic agents such as conductive metal oxides, specifically antimony-doped tin oxide and aluminum-doped zinc oxide can be used. One antistatic agent may be selected and used alone, or two or more antistatic agents may be selected and used in combination. In the present invention, the surface electrical resistance value of the bonded sheet is adjusted to 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □, and the volume electrical resistance value is adjusted to 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm. However, the adjustment is usually made according to the kind and blending amount of the antistatic agent. The antistatic agent is usually added within a range of 3 to 50% by mass.

  The addition of the stabilizer is usually performed within a range of 0.001 to 1% by mass. Specifically, sterically hindered phenol-based, phosphorus-based and amine-based stabilizers can be used. The addition of the light stabilizer is usually performed within a range of 0.001 to 1% by mass. Specifically, sterically hindered amine-based, benzotriazole-based, benzophenone-based light stabilizers, and the like can be used. Addition of a dispersant or a lubricant used for the purpose of dispersing the inorganic fine powder is usually performed within a range of 0.01 to 4% by mass. Specifically, silane coupling agents, higher fatty acid metal soaps such as oleic acid and stearic acid, polyacrylic acid, polymethacrylic acid, and salts thereof can be used.

  The method for producing the polyolefin resin film is not particularly limited, and is appropriately selected from known methods. For example, using a single-layer or multi-layer T die or I die connected to a screw-type extruder, and molding using a cast molding, calender molding, rolling molding, inflation molding method or the like that extrudes molten resin into a sheet. Can do.

  The polyolefin resin film is preferably uniaxially or biaxially stretched. The stretching temperature is preferably 2 to 50 ° C. lower than the melting point of the polyolefin resin. As the stretching method, longitudinal stretching using the peripheral speed difference of the roll group, lateral stretching using a tenter oven, simultaneous biaxial stretching using a combination of a tenter oven and a linear motor, and the like can be used. When a polyolefin-based resin containing a pigment is stretched, what is generally called synthetic paper having fine pores therein can be obtained. Examples of the synthetic paper that can be preferably used in the present invention include this synthetic paper. The polyolefin resin film (synthetic paper) used in the present invention may be composed of a single layer or may have a multilayer structure.

  The thickness of the polyolefin-based resin film used is not particularly limited, but is usually in the range of 15 to 200 μm, preferably in the range of 25 to 150 μm. When the thickness is less than 15 μm, the mechanical strength is weak, and problems such as cutting are likely to occur at the time of bonding with the heat resistant sheet. In addition, unevenness may occur on the surface of the transfer sheet, leading to a decrease in texture and image quality. If the thickness exceeds 200 μm, the price is high. Further, the obtained electrophotographic transfer sheet becomes thick, and there is a disadvantage that the number of sheets loaded (loaded) in the paper supply unit of the printer is reduced.

  In the present invention, the heat-resistant sheet used for bonding to the polyolefin resin film can include a sheet having higher heat resistance than the polyolefin resin film, such as fine paper, coated paper, art paper, cast coat. Paper base materials mainly composed of cellulose pulp such as paper and laminated paper, polyethylene terephthalate and copolymers thereof, polybutylene terephthalate and copolymers thereof, and thermoplastic polyester resin films such as aliphatic polyesters. . In order to adjust the volume electrical resistance value, an antistatic agent may be incorporated into the paper base material and the thermoplastic polyester resin film by coating, dipping, and kneading. Among the heat resistant sheets, a paper base is preferably used because of easy adjustment of the volume electric resistance value.

  Although the thickness of the heat-resistant sheet | seat used is not specifically limited, Usually, it is the range of 50-200 micrometers. When the thickness is less than 50 μm, the mechanical strength at high temperatures and the repulsive force against deformation at the time of fixing of the obtained electrophotographic transfer sheet are insufficient, and curling and paper breakage are likely to occur. If the thickness exceeds 200 μm, the price is high. Further, the obtained electrophotographic transfer sheet becomes thick, and there is a disadvantage that the number of sheets loaded (loaded) in the paper supply unit of the printer is reduced.

The method for laminating a polyolefin resin film on one or both sides of the heat-resistant sheet is not particularly limited, but known methods such as a wet laminating method, an extrusion laminating method, a dry laminating method, and a wax laminating method. Technology is used. In general, the dry laminating method is widely used, and as the polymer resin used at this time, a polyisocyanate-based or epoxy-based curing agent is added to a polyether-based or polyester-based polymer adhesive component. Are often used. The coating amount of the adhesive is desirably in the range of 1 to 30 g / m ² , and the coating amount of the adhesive on the front and back sides is preferably the same in order to maintain the curl balance. In addition, the extrusion laminating method is a preferable production method because a product having good image quality is easily obtained.

  When a polyolefin-based resin film (synthetic paper) is bonded to both sides of a heat-resistant sheet, the same or different types of film may be used for the front and back sides, but the same front and back types may be laminated in terms of blank paper curl and post-printing curl. preferable.

Another aspect of the electrophotographic transfer sheet according to the present invention is that the surface of a polyolefin resin film (synthetic paper) is provided with a toner receiving layer, and the electrophotographic transfer sheet thus obtained has a surface electrical resistance value. 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □ and the volume electrical resistance value is adjusted to 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm. It can be performed on the polyolefin resin film (synthetic paper) before or after bonding.

  The toner receiving layer is a resin-based layer, and a resin that is usually compatible with the toner component is used. Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyurethane resin, polyether resin, polyamide resin, acrylic resin, and cellulose derivative resin. In this coating solution for the receiving layer, a plasticizer, an inorganic pigment, an organic pigment, an antifoaming agent, a wetting agent, a surfactant, an antistatic agent, a crosslinking agent, a thickener, a lubricant, a release agent, You may contain antioxidant, a ultraviolet absorber, a light stabilizer, a fluorescent dye, etc. The addition of a crosslinking agent, a lubricant, and a release agent has an effect of preventing the electrophotographic transfer sheet from being fused to the toner fixing roll. The antistatic agent is used for adjusting the surface electric resistance value or the volume electric resistance value of the electrophotographic transfer sheet. Examples of the antistatic agent include those described above. Among them, inorganic antistatic agents such as conductive metal oxides, specifically antimony-doped tin oxide and aluminum-doped zinc oxide are preferably used.

The toner receiving layer can be provided by a coating method or a printing method. In the coating method, for example, various coating apparatuses such as an air knife coater, rod blade coater, gravure coater, bar coater, blade coater, roll coater, size press coater, curtain coater, lip coater, die coater or slot die coater are appropriately used. used. In the printing method, various printing apparatuses such as screen printing, offset printing, and gravure printing are appropriately used. The coating amount is usually in the range of 0.1 to 20 g / ^{m 2} by solid content, more preferably from 0.5 to 10 g / ^{m 2.} If it is less than 0.1 g / m ^2, the effect cannot be expected, and if it exceeds 20 g / m ² , it is uneconomical.

  The thickness of the electrophotographic transfer sheet of the present invention obtained by bonding is not particularly limited, but it is usually preferable to have a thickness in the range of 100 to 500 μm. When the thickness is less than 100 μm, the mechanical strength at high temperature and the repulsive force against deformation at the time of fixing of the obtained electrophotographic transfer sheet are insufficient, and curling and paper breakage easily occur. On the other hand, if the thickness exceeds 500 μm, there is a disadvantage that the number of sheets loaded (loaded) in the paper supply unit of the printer is reduced.

  The electrophotographic transfer sheet of the present invention can be provided with other layers as required within the range in which the electric resistance value can be adjusted.

  The present invention will be described in more detail with reference to the following examples, but the present invention is of course not limited thereto. In the examples, “parts” and “%” represent “parts by mass (solid content)” and “mass%” unless otherwise specified.

Example 1
[Preparation of pellets]
100 parts by mass of a propylene homopolymer having a melt index of 10 g / 10 min, a crystallinity of 64% and a melting point of 165 ° C., 50 parts by mass of polyethylene glycol (molecular weight 4000) as an antistatic agent, and an average particle diameter of 1.5 μm as an inorganic pigment A biaxial kneading granulator set at 220 ° C. by mixing 30 parts by weight of commercially available heavy calcium carbonate and 0.3 parts by weight of hydrosartite (Kyowa Chemical Industry Co., Ltd .: DHT-4A, trade name) After melt-kneading with [Nex-T60, manufactured by Kobe Steel, Ltd., trade name], it was extruded into a strand shape from a die, and then cut into 2 to 3 mm particles to obtain pellets (resin composition).

[Production of synthetic paper]
The pellets were melted at 230 ° C. using an extruder, supplied into a die and extruded into a sheet having a thickness of 0.4 mm, and cooled to 60 ° C. with a cooling roll. Subsequently, it pre-heated with the heating roll set to 130 degreeC, and it extended | stretched 5 times in the vertical direction between a pair of rolls from which circumferential speed differs, and obtained the 100 micrometer uniaxially stretched film (synthetic paper). The surface electric resistance value and volume electric resistance value of this synthetic paper at 23 ° C. and 50% RH (relative humidity) were 4 × 10 ⁷ Ω / □ and 2 × 10 ⁸ Ω · cm, respectively. (See below for measurement)
(Measurement of surface electrical resistance and volume electrical resistance)
Based on JIS K-6911, the surface electrical resistance value and the volume electrical resistance value were measured under the condition of 23 ° C./50 RH%.

[Preparation of bonded sheet]
Polyurethane adhesive on high-quality paper (OK fine paper 52.3 g / m ² , Oji Paper Co., Ltd.) with a thickness of 67 μm impregnated with sodium chloride so that the coating amount (solid content) is 2 g / m ² (Trademark: AD-593, manufactured by Toyo Morton Co., Ltd.) was applied so that the coating amount (solid content) per side was 5 g / m ^2, and the synthetic paper was adhered to both sides to obtain a bonded sheet. It was.

[Evaluation of bonded sheet]
The surface electrical resistance value and the volume electrical resistance value measured by the above method based on JIS K-6911 of the obtained laminated sheet were 4 × 10 ⁷ Ω / □ and 6 × 10 ⁸ Ω · cm, respectively. The image quality was evaluated by the following method. The results are shown in Table 1.

[Evaluation of image quality]
A printing test was conducted with a color laser printer IPSiO CX9000 and IPSiO CX2500 manufactured by Ricoh Co., Ltd., and the image quality was evaluated. As an image, an ISO / JIS-SCID JIS X 9201-1995 N3 image and an electrophotographic society test chart No5-1 1995 image were used and printed on an A4 size sheet.

Example 2
[Production of synthetic paper]
A pellet was prepared in the same manner as in Example 1 except that 50 parts by mass of polyethylene glycol was changed to 15 parts by mass, and a synthetic paper was produced in the same manner as in Example 1 using this pellet. The surface electric resistance value and the volume electric resistance value at 23 ° C. and 50% RH (relative humidity) of the synthetic paper were 4 × 10 ¹² Ω / □ and 8 × 10 ¹² Ω · cm, respectively.
[Production and evaluation of bonded sheets]
Polyurethane adhesive (trademark: AD-593, manufactured by Toyo Morton Co., Ltd.) on a high-quality paper (OK fine paper 52.3 g / m ² , manufactured by Oji Paper Co., Ltd.) with a thickness of 67 μm. Was 5 g / m ^2, and the synthetic paper was adhered to both sides to obtain a bonded sheet. Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electric resistance value and the volume electric resistance value were 4 × 10 ¹² Ω / □ and 4 × 10 ¹³ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Example 3
[Production and evaluation of bonded sheets]
Polyurethane ionomer (trade name: LA-440A1, manufactured by Hoechst) was applied to 0.5 g / m ^{2 on} one side of the synthetic paper obtained in the same manner as in Example 1. Subsequently, a polyurethane adhesive (trademark: AD-593, Toyo) was applied to a 67 μm-thick high-quality paper impregnated with sodium chloride as in Example 1 (OK fine paper 52.3 g / m ² , manufactured by Oji Paper Co., Ltd.). (Morton Co., Ltd.) is coated so that the coating amount (solid content) per side is 5 g / m ^2, and the coated synthetic paper is bonded to both sides with the polyurethane ionomer coated surface facing outside. Got. Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electrical resistance value and the volume electrical resistance value were 5 × 10 ¹² Ω / □ and 5 × 10 ¹⁰ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Example 4
[Production of synthetic paper]
A pellet was prepared in the same manner as in Example 1 except that 50 parts by mass of polyethylene glycol was changed to 40 parts by mass, and a synthetic paper was produced in the same manner as in Example 1 using this pellet. The surface electric resistance value and volume electric resistance value of the synthetic paper at 23 ° C. and 50% RH (relative humidity) were 3 × 10 ⁸ Ω / □ and 2 × 10 ⁹ Ω · cm, respectively.
[Production and evaluation of bonded sheets]
A high-quality paper having a thickness of 67 μm (OK fine paper 52.3 g / m ² , manufactured by Oji Paper Co., Ltd.) was treated with water for 10 minutes at 100 ° C. to increase the electrical resistance value. Trademark: AD-593, manufactured by Toyo Morton Co., Ltd.) was applied so that the coating amount (solid content) per side was 5 g / m ^2, and the synthetic paper was adhered to both sides to obtain a bonded sheet. . Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electrical resistance value and the volume electrical resistance value were 5 × 10 ⁸ Ω / □ and 3 × 10 ¹³ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Example 5
[Production and evaluation of bonded sheets]
A laminated sheet was obtained in the same manner as in Example 4 except that synthetic paper obtained in the same manner as in Example 1 was used as the synthetic paper. Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electric resistance value and the volume electric resistance value were 5 × 10 ⁷ Ω / □ and 5 × 10 ¹³ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Example 6
[Preparation of toner receiving layer coating solution]
100 parts by mass of conductive metal oxide (trade name: basset CK, zinc oxide manufactured by Hakusuitec Co., Ltd.) polyurethane ionomer (trade name: Hydran AP20, manufactured by Dainippon Ink & Chemicals, Inc.) 100 parts by mass dispersant (trade name: Aron A-9) , Manufactured by Toa Gosei Co., Ltd.) 1 part by mass was mixed and stirred, and water was added to prepare a coating solution having a concentration of 20%.
[Formation and Evaluation of Toner Receiving Layer on Laminated Sheet]
On the laminated sheet obtained in the same manner as in Example 1, the toner receiving layer coating solution was applied on both sides so that the coating amount (solid content) per side was 5 g / m ² . Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electrical resistance value and the volume electrical resistance value were 1 × 10 ¹⁰ Ω / □ and 1 × 10 ¹¹ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Comparative Example 1
[Production of synthetic paper]
A pellet was prepared in the same manner as in Example 1 except that 50 parts by mass of polyethylene glycol was changed to 60 parts by mass, and a synthetic paper was produced in the same manner as in Example 1 using this pellet. The surface electric resistance value and volume electric resistance value of the synthetic paper at 23 ° C. and 50% RH (relative humidity) were 1 × 10 ⁶ Ω / □ and 4 × 10 ⁷ Ω · cm, respectively.
[Production and evaluation of bonded sheets]
Polyurethane adhesive (trademark: AD-593, manufactured by Toyo Morton Co., Ltd.) on high-quality paper (OK fine paper 52.3 g / m ² , manufactured by Oji Paper Co., Ltd.) with a thickness of 67 μm (solid content) Was 5 g / m ^2, and the synthetic paper was adhered to both sides to obtain a bonded sheet. Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electrical resistance value and the volume electrical resistance value were 1 × 10 ⁶ Ω / □ and 5 × 10 ¹⁰ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Comparative Example 2
[Production and evaluation of bonded sheets]
A polyurethane adhesive (trademark: AD-593, manufactured by Toyo Morton Co., Ltd.) was used on a fine paper of 67 μm thickness (OK fine paper 52.3 g / m ² , manufactured by Oji Paper Co., Ltd.) impregnated with sodium chloride as in Example 1. ) Was applied so that the coating amount (solid content) per side was 5 g / m ^2, and then a synthetic paper obtained in the same manner as in Comparative Example 1 was adhered to both sides to obtain a bonded sheet. . Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electrical resistance value and the volume electrical resistance value were 1 × 10 ⁶ Ω / □ and 1 × 10 ⁷ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Comparative Example 3
[Production of synthetic paper]
A pellet was prepared in the same manner as in Example 1 except that 40 parts by mass of polyethylene glycol was changed to 0 part by mass, and a synthetic paper was produced in the same manner as in Example 1 using this pellet. The surface electric resistance value and the volume electric resistance value of the synthetic paper at 23 ° C. and 50% RH (relative humidity) were 5 × 10 ¹³ Ω / □ and 1 × 10 ¹⁴ Ω · cm, respectively.
[Production and evaluation of bonded sheets]
Polyurethane adhesive (trademark: AD-593, manufactured by Toyo Morton Co., Ltd.) on a high-quality paper (OK fine paper 52.3 g / m ² , manufactured by Oji Paper Co., Ltd.) with a thickness of 67 μm. Was 5 g / m ^2, and the synthetic paper was adhered to both sides to obtain a bonded sheet. Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface resistance value and the volume resistance value were 5 × 10 ¹³ Ω / □ and 3 × 10 ¹⁴ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

Comparative Example 4
[Production and evaluation of bonded sheets]
Polyurethane ionomer (trade name: LA-440A1, manufactured by Hoechst) was applied to 0.1 g / m ^{2 on} one side of a synthetic paper obtained in the same manner as in Comparative Example 1. Subsequently, a polyurethane adhesive (trademark: AD-593, Toyo) was applied to a 67 μm-thick high-quality paper impregnated with sodium chloride as in Example 1 (OK fine paper 52.3 g / m ² , manufactured by Oji Paper Co., Ltd.). (Morton Co., Ltd.) is coated so that the coating amount (solid content) per side is 5 g / m ^2, and the coated synthetic paper is bonded to both sides with the polyurethane ionomer coated surface facing outside. Got. Subsequently, the surface electric resistance value and the volume electric resistance value were measured in the same manner as in Example 1. The surface electrical resistance value and the volume electrical resistance value were 5 × 10 ⁷ Ω / □ and 1 × 10 ⁷ Ω · cm, respectively. The image quality was also evaluated. The results are shown in Table 1.

The transfer sheet for electrophotography of the present invention is excellent in durability and water resistance, and can always obtain a good image stably. Therefore, it is used in severe environments such as high humidity, chemical exposure, and outdoors. Very useful for documents, drawings, photographs, maps, manuals, labels, tags, etc.

Claims (5)

In the electrophotographic transfer sheet in which the polyolefin resin film layer is provided on at least one surface of the heat resistant sheet, the electrophotographic transfer sheet has a surface electrical resistance value of 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □. And an electrophotographic transfer sheet having a volume electric resistance value of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm. An electrophotographic transfer sheet comprising a polyolefin resin film layer provided on at least one surface of a heat resistant sheet, and further provided with a toner receiving layer on the surface of the polyolefin resin film layer, the surface of the electrophotographic transfer sheet An electrophotographic transfer sheet having an electric resistance value of 1 × 10 ⁷ to 1 × 10 ¹³ Ω / □ and a volume electric resistance value of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω · cm. The electrophotographic transfer sheet according to claim 1, wherein the polyolefin-based resin film is a film obtained by uniaxially or biaxially stretching containing a pigment and an antistatic agent as components. . 4. The electrophotographic transfer sheet according to claim 1, wherein a value (VR / SR) obtained by dividing the volume electric resistance value by the surface electric resistance value is 10 ⁻⁵ to 10 ⁵ . The electrophotographic transfer sheet according to claim 2, wherein the toner receiving layer contains a conductive metal oxide.