JP2002258509A - Electrophotographic transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic transfer sheet which obviates the paper jam in discharging the paper by heat curling, the fusion of the transfer sheet and the generation of the cut paper in a heat roll section for fixing and the occurrence of cylindrical curling after the passage of the paper and is good in image quality and water resistance after image printing and water resistance. SOLUTION: This transfer sheet is used for an electrophotographic system for forming the images by toner particles is a laminate formed by adhering and laminating a paper base or a core material layer (B) of 50 to 200 μm in thickness consisting of a thermoplastic polyester resin film and thermoplastic resin film layers (A) on both surfaces of this core material (B). The thermoplastic resin films formed the thermoplastic resin film layers (A) are characterized in that the thermal shrinkage after the heat treatment for 30 minutes at 120 deg.C is <=5%. The thermoplastic resin films are preferably synthetic paper consisting of stretched films essentially consisting of polyolefinic resins and inorganic pigments.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to documents, drawings, photographs, maps, manuals, tags, and the like, which are used by being brought or affixed to the environment such as high humidity, chemical exposure, and outdoors. The present invention relates to a transfer sheet for electrophotography having useful writing properties, water resistance, tear resistance and good image quality.

[0002]

2. Description of the Related Art Conventionally, heat-fixed electrophotographic printers use PPC paper, which is high-quality paper, and OHP sheets, which are surface-treated with polyester films. However, PPC paper is limited to use in applications where water resistance, chemical resistance and strength are not required, and OHP sheets have water resistance and chemical resistance but are transparent, so their use is limited to OHP applications. I have. On the other hand, in applications where water resistance, chemical resistance and strength are required in printing methods such as offset printing and screen printing, synthetic paper mainly composed of polypropylene has been used conventionally, and high humidity, chemical exposure, outdoor use, etc. Documents to be brought or affixed to the environment of the
It is used for applications such as drawings, photographs, maps, manuals, labels, and tags.

However, in a heat roll fixing type electrophotographic printer, the surface temperature of the heat roll at the time of fixing the toner is 1%.
70 to 200 ° C, exceeding the melting point of polypropylene which is a main raw material of synthetic paper. For this reason, when synthetic paper mainly composed of polypropylene (for example, Japanese Patent Publication No. 46-40794) is passed through a heat roll fixing type electrophotographic printer, curling due to heat occurs, and paper passing failure occurs,
There was a problem in running properties such as the printed matter being rounded and the synthetic paper being melted and cut off in the fixing heat roll section.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a heat roll fixing type electrophotographic printer, in which paper jam due to thermal curl at the time of discharge, fusing of a transfer sheet at a fixing heat roll portion, and occurrence of paper breakage. Another object of the present invention is to provide a transfer sheet for electrophotography which does not cause cylindrical curl after paper passing and has good image quality and water resistance after printing.

[0005]

Means for Solving the Problems The transfer sheet for electrophotography according to the present invention is used in an electrophotographic system in which an image is formed by toner particles, and the transfer sheet is formed of a paper support or a thermoplastic polyester resin film. Core material layer (B) having a thickness of 50 to 200 μm, and the core material layer (B)
A thermoplastic resin film layer (A) is bonded and laminated on both surfaces of the thermoplastic resin film layer (A), and the thermoplastic resin film forming the thermoplastic resin film layer (A) is at 120 ° C.
The heat shrinkage after heat treatment for 30 minutes is 5% or less. Further, the thermoplastic resin film,
It is preferably a synthetic paper made of a stretched film mainly containing a polyolefin resin and an inorganic pigment.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION (A) Thermoplastic resin film As the thermoplastic resin film used in the present invention, for example, ethylene-based resins such as high-density polyethylene and medium-density polyethylene, propylene-based resins, Polymethyl-1-pentene, polyolefin-based resin such as ethylene-cyclic olefin copolymer, polyamide-based resin such as nylon-6, nylon-6,6, polyethylene terephthalate and its copolymer, polybutylene terephthalate and its copolymer,
Thermoplastic polyester resins such as aliphatic polyesters,
Polycarbonate, atactic polystyrene, syndiotactic polystyrene and the like can be mentioned. Among them, it is preferable to use a polyolefin resin.

Among the polyolefin resins, it is preferable to use a propylene resin from the viewpoint of chemical resistance and cost. Examples of the propylene-based resin include an isotactic polymer or a syndiotactic polymer obtained by homopolymerizing propylene. Α, such as ethylene, 1-butene, 1-hexene, and 4-methyl-1-pentene;
-Copolymers obtained by copolymerizing olefins and propylene and having propylene as a main component and having various stereoregularities can also be used. The copolymer may be a binary system, a ternary or higher system, a random copolymer or a block copolymer. It is preferable that a resin having a melting point lower than that of the propylene homopolymer is blended in the propylene-based resin in an amount of 2 to 25% by weight. Examples of such a resin having a low melting point include high-density to low-density polyethylene. As the thermoplastic resin, one of the above thermoplastic resins may be selected and used alone, or two or more may be selected and used in combination.

[0008] The thermoplastic resin may contain, if necessary, an inorganic fine powder, an organic filler, a stabilizer, a light stabilizer, a dispersant,
A lubricant or the like can be added. When adding an inorganic fine powder, one having a particle size of 0.01 to 5 μm is preferably used. Specifically, heavy calcium carbonate, light calcium carbonate, calcined clay, silica, talc, titanium oxide, barium sulfate, alumina and the like can be used. When adding an organic filler, it is preferable to select a resin different from the thermoplastic resin as the main component. For example, when the thermoplastic resin is a polyolefin resin, polyethylene terephthalate as an organic filler,
Use a polymer such as polybutylene terephthalate, polycarbonate, nylon-6, nylon-6,6, cyclic olefin, polystyrene, polymethacrylate, etc., having a melting point higher than the melting point of the polyolefin resin or a glass transition temperature. be able to. When adding an inorganic fine powder and / or an organic filler, it is preferably added in the range of 3 to 50% by weight.

When a stabilizer is added, usually 0.001
It is added within the range of １1% by weight. Specifically, sterically hindered phenol-based, phosphorus-based, and amine-based stabilizers can be used. When adding a light stabilizer, usually 0.001 to
It is added within a range of 1% by weight. Specifically, sterically hindered amine-based, benzotriazole-based, benzophenone-based light stabilizers and the like can be used. The dispersant and the lubricant are used, for example, for the purpose of dispersing the inorganic fine powder. The amount added is usually in the range of 0.01 to 4% by weight. Specifically, silane coupling agents, metal soaps of higher fatty acids such as oleic acid and stearic acid, polyacrylic acid, polymethacrylic acid, and salts thereof can be used.

[0010] The method of forming the thermoplastic resin film is not particularly limited, and the thermoplastic resin film can be formed by appropriately selecting from known methods. For example, using a single-layer or multi-layer T-die or I-die connected to a screw-type extruder to extrude the molten resin into a sheet, cast molding, calender molding, rolling molding, or inflation molding. Can be.

The thermoplastic resin film is preferably uniaxially or biaxially stretched. Stretching can be performed by any of various methods commonly used. The stretching temperature is preferably higher than the glass transition temperature of the thermoplastic resin to be used in the case of the non-crystalline resin, and is higher than the glass transition temperature of the non-crystal part to the melting point of the crystal part in the case of the crystalline resin. Can be performed in a suitable temperature range. Specifically, a temperature lower by 2 to 50C than the melting point of the thermoplastic resin is preferable. As the stretching method, longitudinal stretching using the peripheral speed difference of the roll group, transverse 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.

The stretching ratio is appropriately determined in consideration of the characteristics of the thermoplastic resin used. For example, when using a propylene homopolymer or a copolymer thereof as the thermoplastic resin, when stretching in one direction is preferably 2 to 10 times,
In the case of biaxial stretching, the area ratio is preferably 10 to 50 times.

When a thermoplastic resin containing an inorganic fine powder or an organic filler is stretched, a stretched porous resin film having fine pores therein can be obtained. The stretched thermoplastic resin film may be composed of a single layer, or may have a multilayer structure.

The thickness of the thermoplastic resin film is usually 15 to
In the range of 200 μm, preferably 25-150 μm
m. The thickness of the thermoplastic resin film is 15
If it is less than μm, the thickness of the resulting electrophotographic transfer sheet is small, the mechanical strength becomes insufficient, and curling due to heat may not be sufficiently prevented. On the other hand, when the thickness exceeds 200 μm, the thickness of the obtained electrophotographic transfer sheet becomes excessively large, and the number of sheets supplied to the paper supply unit of the printer decreases, which is disadvantageous economically.

The thermoplastic resin films laminated on both sides of the core material layer may be the same film on the front and back, or the types of the front and back films may be different. When laminating a polypropylene resin film on one surface of the core material layer, laminating a polypropylene resin film on the other surface,
It is preferable in terms of curling blank paper and curling after printing.

The thermoplastic resin film (A) of the present invention
As for the heat shrinkage after the heat treatment at 20 ° C. for 30 minutes, the average value of the heat shrinkage in both the vertical and horizontal directions is within 5%, preferably within 3%. If it exceeds 5%, the transfer sheet for electrophotography after printing will have a large curl, and will be curved or cylindrical, resulting in poor stackability at the time of paper discharge and poor workability. The thermal shrinkage rate is determined by cutting the thermoplastic resin film (A) into a square of a predetermined size, for example, 200 mm in both length and width, measuring the size in an environment of 23 ° C. and 50% relative humidity, and then blowing and drying at 120 ° C. Heat treatment for 30 minutes in a machine, take out, allow to cool for 1 hour in an environment of 23 ° C. and 50% relative humidity, measure the dimensions, calculate the heat shrinkage by comparing with the dimensions before heat treatment Can be.

(B) Core Material Layer The core material layer used in the present invention may be made of paper such as woodfree paper, coated paper, art paper, cast coated paper or the like containing cellulose pulp as a main component. Processed paper such as laminated paper provided with a resin layer is preferably used. In addition, thermoplastic polyester resin films such as polyethylene terephthalate and its copolymers, polybutylene terephthalate and its copolymers, and aliphatic polyesters have heat resistance, and have a smooth surface and small unevenness, so that the image quality after printing is low. Since it is good, it is preferably used.

The sheet-like core material layer used in the present invention has a thickness of 50
It preferably has a thickness of ~ 200 [mu] m. Thickness 5
When the thickness is less than 0 μm, the mechanical strength of the obtained electrophotographic transfer sheet becomes insufficient, and the repulsive force against deformation becomes insufficient, so that the curling of the electrophotographic transfer sheet which occurs at the time of printing cannot be sufficiently prevented. There is. If the thickness exceeds 200 μm, the thickness of the electrophotographic transfer sheet increases and the number of sheets supplied to the paper supply unit of the printer decreases, and the image quality decreases due to the unevenness of the core layer and the texture of the transfer sheet increases. May be inferior.

The method of bonding and laminating the thermoplastic resin film layer (A) on both sides of the core layer (B) is not particularly limited, but includes a wet lamination method, an extrusion lamination method, and a dry lamination method. A publicly known technique such as a wax method or a wax laminating method is used. In general, a dry lamination method is widely used, and a polymer resin used at this time is a polyether-based resin,
In many cases, a mixture of a polymer adhesive component such as a polyester and a curing agent such as a polyisocyanate or an epoxy is used. The coating amount of the adhesive is 1 to 30 g / m ^2.
In order to maintain the curl balance, it is preferable to make the coating amount of the adhesive on the front side film layer and the back side film layer the same. An extrusion lamination method is also preferably used for high image quality. The laminate obtained in the present invention preferably has a thickness of 100 to 500 μm.

The laminate obtained in the present invention may be used as it is as a transfer sheet for electrophotography. However, at least one surface of the laminate is subjected to a conductive treatment in order to improve printability and antistatic properties. Is preferred. For the antistatic treatment, ordinary organic and inorganic antistatic agents are used. 0.01 to 3 g /
antistatic effect is obtained with m ² by applying the thermoplastic film surface. 23 ° C. on the antistatic surface
The surface resistance under an environment of 50% relative humidity is 1.0 ×
It is preferably from 10 ^{8 to} 1.0 × 10 ¹² (Ω / □).

[0021]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but of course, the present invention is not limited thereto.

Example 1 Fine wood having a thickness of 67 μm (OK fine wood 52.3 g / m ² ,
Oji Paper Co., Ltd.), a 60 μm thick polypropylene-based multilayer structure film (trade name: YUPO FPU60) containing 30% by weight of calcium carbonate as an inorganic pigment, a skin layer being uniaxially stretched, and a core layer being biaxially stretched. And a heat shrinkage of 1.3% manufactured by YUPO CORPORATION) using a polyurethane-based adhesive (trade name: AD-593, manufactured by Toyo Morton Co., Ltd.) at a coating amount of 5 g / m ^2. An electrophotographic transfer sheet was obtained.

Example 2 100 μm thick coated paper (OK Topcoat N12
7.9 g / m ² , manufactured by Oji Paper) contains about 30% by weight of calcium carbonate as an inorganic pigment,
A 110 μm-thick polypropylene-based multilayer structure film (trade name: YUPO FPG) which is axially stretched and whose core layer is biaxially stretched
110, manufactured by YUPO Corporation, heat shrinkage 1.8
%) With a polyurethane-based adhesive (trademark: AD-593,
Using Toyo Morton Co., Ltd.), a transfer amount of 5 g / m ² was applied and laminated to obtain an electrophotographic transfer sheet.

Example 3 A biaxially oriented polyester film having a thickness of 100 μm (E5
100 # 100 (manufactured by Toyobo Co., Ltd.), a 60 μm-thick polypropylene-based multilayer structure film (trademark) containing about 30% by weight of calcium carbonate as an inorganic pigment, a skin layer being uniaxially stretched, and a core layer being biaxially stretched. : Yupo FPU6
0, made by YUPO Corporation, heat shrinkage 1.3%)
Was adhered and laminated using a polyurethane adhesive (trade name: AD-593, manufactured by Toyo Morton Co., Ltd.) at a coating amount of 5 g / m ² to obtain an electrophotographic transfer sheet.

Example 4 A coated paper having a thickness of 60 μm (OK Topcoat N 73.
3 g / m ² , manufactured by Oji Paper Co., Ltd.) On both sides, a 50 μm thick polypropylene-based multilayer structure containing about 30% by weight of calcium carbonate as an inorganic pigment, a skin layer being uniaxially stretched, and a core layer being biaxially stretched Film (trademark: YUPO FPU50,
Electro-photography by bonding and laminating a heat-shrinkage rate of 1.7% manufactured by YUPO CORPORATION using a polyurethane adhesive (trade name: AD-593, manufactured by Toyo Morton Co., Ltd.) at a coating amount of 5 g / m ^2. Transfer sheet was obtained.

Comparative Example 1 Fine wood having a thickness of 152 μm (OK fine paper 127.9 g / m 2
² , Oji Paper Co., Ltd.)
m of a polypropylene film (trade name: Pyrene film P6183, manufactured by Toyobo, heat shrinkage: 6.0%) using a polyurethane-based adhesive (trade name: AD-593, manufactured by Toyo Morton Co., Ltd.) at a coating amount of 5 g / to obtain a transfer sheet for electrophotography was bonded and laminated in m ^2.

Comparative Example 2 Fine paper having a thickness of 250 μm (OK Prince fine quality 209.3)
g / m ² , manufactured by Oji Paper Co., Ltd.)
A 50 μm-thick polypropylene-based multilayer film (trade name: YUPO FPU50, manufactured by YUPO Corporation) containing 0% by weight of calcium carbonate, a uniaxially stretched skin layer and a biaxially stretched core layer, having a heat shrinkage of 1.7 %) With a polyurethane adhesive (trade name: AD-593, manufactured by Toyo Morton Co., Ltd.) at a coating amount of 5 g / m ² to obtain a transfer sheet for electrophotography.

Comparative Example 3 Including about 30% by weight of calcium carbonate as an inorganic pigment,
Thickness 5 in which the skin layer is uniaxially stretched and the core layer is biaxially stretched
0 μm polypropylene multilayer film (trademark: U
PoFPU50, made by YUPO Corporation, heat shrinkage
(1.7%) as a core material layer and a thickness of 67 on both sides of the film.
μm fine paper (OK fine paper 52.3 g / m ², Oji Paper
Made of polyurethane-based adhesive (trade name: AD-593,
Using Toyo Morton Co., Ltd.)²Glued in
・ Laminated to obtain electrophotographic transfer sheet

Comparative Example 4 Including about 30% by weight of calcium carbonate as an inorganic pigment,
Thickness 1 in which the skin layer is uniaxially stretched and the core layer is biaxially stretched
10 μm polypropylene-based multilayer structure film (trademark:
YUPO FPG110, manufactured by YUPO CORPORATION, heat shrinkage 1.8%) was used as it was as an electrophotographic transfer sheet.

Comparative Example 5 Fine paper having a thickness of 95 μm (trademark: OK fine paper 81.4 g /
m ² , manufactured by Oji Paper) as an electrophotographic transfer sheet

(Evaluation Method) The obtained electrophotographic transfer sheet was cut into an A4 size (210 mm width, 297 mm flow).
1 in a constant temperature and humidity room at 23 ° C and 50% relative humidity
After leaving for a day, heat roll fixing type electrophotographic printer:
Printing was performed with a laser shot A404G11 (manufactured by Canon Inc.) by a paper passing method with the printed screen facing upward (also referred to as face-up paper passing), and the following items were evaluated. The results of the evaluation are shown in Table 1 below.

(1) Print curl: The sheet after printing on the printer is left on a flat table in a constant temperature and humidity room at 23 ° C. and 50% relative humidity. The average value of the curl height was measured and evaluated according to the following criteria. ：: Average height within 20 mm ×: Average height exceeding 20 mm (2) Image quality: The uniformity of the image of the printed product was visually evaluated. ：: Good image uniformity ×: Poor image uniformity (3) Water resistance: The sheet printed with a printer was immersed in tap water overnight, pulled up, and the printed image was lightly wiped with a tissue and then torn. ：: The sample is torn with both hands and does not tear, and the stamp screen is not damaged. ×: The sample is torn with both hands, tears or scratches the stamp screen. (4) Trouble resistance: Transfer sheet for electrophotography is printer Was evaluated when stopped at the fixing unit. ：: No transfer sheet adhered to electrophotographic transfer sheet ×: Surface of electrophotographic transfer sheet melted, causing printer trouble

[0033]

[Table 1]

According to Examples 1 to 4, the transfer sheet for electrophotography according to the present invention has a good print curl after printing of 20 mm or less, and is excellent in the paper discharge property and the stackability of the printed product. Also, the image quality and water resistance of the printed product and the trouble resistance of the printer are good.

On the other hand, Comparative Example 1 has a drawback that the thermal curl of the thermoplastic resin film exceeds 5%, so that the printed curl is large. In Comparative Example 2, since the thickness of the paper of the core material layer is large, the image quality is deteriorated due to the unevenness of the paper. In Comparative Examples 3 and 5, since the paper support is exposed on the surface of the laminate, there is a disadvantage that the water resistance is poor and the image quality of the printed product is inferior. In Comparative Example 4, since YUPO alone was used, when stopped inside the printer, it adhered to the heat roll, causing a traveling trouble.

[0036]

According to the present invention, in printing of a heat roll fixing type electrophotographic printer, there is no paper jam due to thermal curl at the time of discharge and no rounding after printing, and the image quality and water resistance of the print are improved. A good transfer sheet for electrophotography can be obtained, which greatly contributes to the industry.

Claims (2)

[Claims] 1. A transfer sheet for electrophotography used for electrophotography in which an image is formed by toner particles, wherein the transfer sheet is made of a paper support or a thermoplastic polyester resin film and has a thickness of 50 to 200 μm. (B) and a laminate obtained by bonding and laminating a thermoplastic resin film layer (A) on both surfaces of the core material layer (B),
A transfer sheet for electrophotography, wherein the thermoplastic resin film forming the thermoplastic resin film layer (A) has a heat shrinkage of 5% or less after heat treatment at 120 ° C. for 30 minutes. 2. The electrophotographic transfer sheet according to claim 1, wherein the thermoplastic resin film is a synthetic paper composed of a stretched film containing a polyolefin resin and an inorganic pigment as main components.