JP2866762B2 - Transfer film for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic transfer film for carrying a toner image formed by electrophotography.

[0002]

2. Description of the Related Art In recent years, it has been widely practiced to form an image on a transparent film by an electrophotographic method, to provide a transparent film having a toner image to OHP, and to use it as a projected image. In the electrophotographic method, when transferring the toner on the electrostatic latent image, because there is a discharge portion such as charging the transfer target film at a high pressure, if the surface electric resistance of the film is high,
Discharge marks are generated in the copying machine. In order to prevent the discharge mark, it has been proposed to control the surface electric resistance to a certain area. However, in a full-color image, in order to transfer four color toners, if the surface resistance is too low, the toner transferred first leaks charge on the film to be transferred, and the adhesive force to the film to be transferred decreases, At the time of the next toner transfer, there is a problem that the toner image is re-transferred onto the electrostatic latent image holding member, and that color loss and image density are reduced. Further, in the conventional electrophotographic system, since the refraction of incident light generated at the boundary surface between the toner and the air is large, only a dark projected image with low chroma can be obtained. To solve this problem,
It is necessary to reduce the unevenness of the toner image formed on the transparent film, and various methods have been conventionally proposed as described below, but the above problem could not be completely solved.

For example, Japanese Patent Publication No. 51-34734 discloses that the optimum surface resistance of a black-and-white electrophotographic transfer film is one.
Although it is described as 0 ¹⁰ to 10 ¹² Ω, in a full-color system, if the surface electric resistance is simply reduced, it is 10 ¹¹ Ω /.
□ Retransfer occurs below. Or 10 ¹² Ω /
□ Above, discharge marks are generated as in Japanese Patent Publication No. 51-34734. Therefore, in the full color system,
The range of the optimum surface resistance is extremely limited. For example, JP-A-59-184361 proposes a method of spray-coating a lacquer or the like on the surface of a toner image. However, the toner is dissolved by a solvent to lower the sharpness of the image.
Problems such as color unevenness or contamination of a non-image portion occur. JP-A-60-52861 proposes a method of coating a toner image with a laminate film.
JP-A-61-36756 and JP-A-61-36762 propose a method in which a transparent film is superimposed on a toner image and heat roll-fixed, and then the transparent film is peeled off. However, these methods have problems such as an increase in the number of processing steps after image formation, and destruction of the toner image when the transparent film is peeled off.

Japanese Patent Application Laid-Open No. 63-80273 discloses a method for fixing a toner at a temperature at which the toner is sufficiently dissolved, a method for fixing using a solvent such as toluene, a method for polishing a fixed image surface, and a method for dissolving a toner. There has been proposed a method of applying a transparent paint to the toner image after fixing, but in the case of a roller fixing method at a high temperature, if an attempt is made to reduce irregularities in a portion having a small amount of toner such as a halftone portion, the amount of toner is reduced. Offsets are generated in many parts, and a non-contact heat fixing device such as an oven has a drawback that a transparent film is wavy and a considerable fixing time is required to obtain sufficient translucency. . In the case of the method using a solvent, there is a drawback that when the fluidity of the toner is increased by the solvent until the unevenness of the toner in the halftone portion is reduced, the image is distorted and the flow occurs in the high density portion. In the case of the method of polishing an image, the transparency is increased in a portion having a relatively large amount of toner, but there is a disadvantage that unevenness of the toner cannot be sufficiently reduced in a low density region. Furthermore, in the case of a method of applying a transparent paint that does not dissolve the toner on the toner image, a clear boundary may be formed on the toner image with the toner particles, and the incident light is scattered at this boundary surface, and the saturation is low. There is a disadvantage that a dark projected image is obtained.

[0005] Japanese Patent Application Laid-Open No. Hei 2-263624 discloses a method for reducing the unevenness of a toner image formed on a transparent film, which is compatible with a toner binder resin and has a lower temperature than a toner binder resin at a toner fixing temperature. Also, a method has been proposed in which a transparent resin layer having a large storage modulus is provided on a transparent film. However, in the case of this method, since the storage elastic modulus of the transparent resin layer is larger than that of the toner binder resin, the toner hardly sinks into the transparent resin layer, or the toner hardly diffuses in the lateral direction, and the toner image is hardly formed. In order to reduce unevenness, it is necessary to make the transparent resin layer thick enough and force the toner to sink by high pressure using a heat roller with high hardness, and make the transparent resin layer too thick This causes problems such as image blur, distortion, and image cracking due to bending, wrinkles during fixing due to high-pressure fixing with a high-hardness heat roll, and an increase in curl after fixing.

Further, when a color image is formed digitally, the density of each color is changed by changing the area of minute dots or lines. The fixing device makes the halftone part sufficiently smooth, but the halftone part has large irregularities due to the image structure of dots and lines and does not become sufficiently smooth, so the incident light is refracted and the halftone part of the projected image becomes saturated. When a natural image such as a photograph is reproduced due to a darkened image having a low density, a shadow (hereinafter, referred to as a “pseudo-contour”) that is not included in the original in the halftone portion is likely to occur.

[0007] In order to improve the false contour that is likely to occur when a digital color image is formed, it is necessary to sufficiently sink the toner image into the transparent resin layer on the transparent film or to diffuse the toner image in the lateral direction. 2-2.
In the case of using a method proposed in US Pat. No. 63,642, that is, using a transparent film coated with a transparent resin having a higher storage elastic modulus than the toner binder resin, the toner image hardly sinks into the transparent resin layer, or Since the toner image is hardly diffused in the horizontal direction, the unevenness of the toner image in the halftone portion cannot be sufficiently reduced, and therefore, it is difficult to prevent the occurrence of the false contour.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned problems in the prior art, and to prevent retransfer and improve the quality of discharge marks as compared with the prior art. Provided is a transfer film for electrophotography that has a wide optimum surface resistance that can also prevent generation, has high saturation, is bright, has good color tone reproducibility, and can produce a color projection image free from false contours by a simple method. Is to do.

That is, one of the objects of the present invention is to provide a transfer film for electrophotography capable of forming a good full-color projected image. Another object of the present invention is to provide an electrophotographic transfer film with reduced surface electric resistance that does not cause retransfer. Another object of the present invention is to provide a transfer film for electrophotography capable of forming a full-color projected image having high lightness and saturation. Another object of the present invention is to provide an electrophotographic transfer film excellent in reproducibility of a full-color image. Another object of the present invention is to provide a transfer film for electrophotography which improves a false contour which is likely to occur when a digital color image is formed. Another object of the present invention is to provide an electrophotographic transfer film having excellent fixability of a full-color toner image. Still another object of the present invention is to provide an electrophotographic transfer film capable of forming a good full-color projected image by a simple method.

[0010]

SUMMARY OF THE INVENTION The present inventors have studied the improvement of retransfer from the viewpoints of leakage of the charge of the toner and the characteristics of the adhesive force between the toner, the film to be transferred, and the toner. By using an antistatic agent having a charge opposite to that of the charge, the adhesion between the toner and the film surface is improved, and a polymer compatible with the binder resin of the toner is provided on the film to be transferred. It was found that the adhesion between the toner and the film surface was improved. The improvement of the saturation, brightness, color tone reproducibility, fixing degree and pseudo contour of the color projected image was examined from the viewpoint of the composition of the coating amount of the electrophotographic transfer film and the characteristics of the resin. For the electrophotography, a transparent resin layer having the compatibility with the toner binder resin at the fixing temperature of the toner used for color image formation and having a lower viscosity at the fixing temperature than the binder resin is provided on the above plastic film. The present inventors have found that the above problems can be greatly improved by using a film to be transferred, and have completed the present invention.

That is, according to the present invention, an electrostatic latent image holding member
In an electrophotographic transfer film used for electrophotography in which a charged toner is adsorbed and transferred onto a transfer target film, at least one surface of a plastic film having a heat-resistant temperature of 100 ° C. or higher has an apparent appearance from the toner binder resin. Melt viscosity
Low and the toner melt angle at the toner fixing temperature
An electrophotographic transfer film provided with a layer containing a transparent resin at a temperature of 40 ° C. or lower . In addition, the present invention
In a preferred embodiment, the charged toner is absorbed on the electrostatic latent image holding member.
Used in electrophotography to attach and transfer onto the film to be transferred
Heat-resistant temperature of 100 ° C
On at least one side of the above plastic film,
The opposite of the charge of the layer containing the thermoplastic resin and the toner
Layer containing an antistatic agent having, or a thermoplastic resin
A layer containing the antistatic agent was provided on the layer containing
A transfer film for electrophotography, characterized in that: In a preferred embodiment of the present invention, the electrophotographic transfer film used in the electrophotographic method in which the charged toner is adsorbed on the electrostatic latent image holding member and transferred onto the transfer film, has a heat resistance temperature of 100 ° C. or higher. The angle of inclination of the molten toner with the toner to be fixed at at least one surface of the plastic film is 40 ° or less, and the apparent melting temperature at 100 ° C. is 1 × 10 ^{3 to} 7 ×.
A layer containing a transparent thermoplastic resin of 10 ⁴ poises and a cationic antistatic agent, or a layer containing the thermoplastic resin.
And a layer containing the antistatic agent provided on the layer to be transferred. Further, the subject film for electrophotography of the present invention can be formed by forming a color toner image formed from a toner containing at least a colorant and a binder resin on a film, and fixing the film by applying heat and pressure. it can.

In the electrophotographic transfer film of the present invention, as the plastic film, specifically, a polyethylene terephthalate film having a heat-resistant temperature of 100 ° C. or higher, a polysulfone film, a polyphenylene oxide film, a polyimide film, a polycarbonate film, a cellulose film Examples thereof include an acetate film and a polyamide film. Among them, a polyethylene terephthalate film is particularly preferred in terms of heat resistance and transparency. If the heat resistance temperature of the plastic film is less than 100 ° C., the toner is deformed when thermally fixed, and cannot be used. Further, the thickness of the plastic film is required to be such that no wrinkles are generated when the film is softened by heating at the time of heat fixing, and is generally required to be 50 μm or more, preferably 75 μm or more. The upper limit of the thickness of the plastic film is 200 μm or less, preferably 1 μm, in consideration of a decrease in light transmittance.
It is preferably 50 μm or less. Therefore, the thickness of the heat-resistant plastic film may be set in the range of 50 to 200 μm, preferably 75 to 150 μm.

In the conventional black-and-white electrophotography system, when a selenium-based photoconductor is used, the photoconductor is mainly charged positively and the toner is negatively charged. After that, the development of the organic photoreceptor progressed. When the organic photoreceptor was used, the method of charging the photoreceptor negatively and the method of charging the toner positively became main. When transferring a positively charged toner, the antistatic agent on the film to be transferred is an anionic antistatic agent such as an alkylbenzene fonate, which has a large electrical interaction with the toner and improves transfer efficiency. .

In the full-color electrophotographic system, the resolving power has to be remarkably improved as compared with black and white. The photoreceptor uses an organic photoreceptor, and the photoreceptor is negatively charged, but employs an image writing method to improve resolution. In other words, the negative charge of the image portion on the negatively charged photoreceptor is eliminated by the laser, and a non-charged portion is generated in the negatively charged sea. The uncharged portion acts as if it has a positive charge, and adsorbs negatively charged toner. In this method, of course, a cationic antistatic agent having a large interaction with the negatively charged toner is effective in improving transferability and preventing retransfer on the film to be transferred. Heterocyclic amines, ammonium salts, sulfonium salts, phosphonium salts, betaine amphoteric salts and the like can be used as the cationic antistatic agent. Among them, quaternary ammonium salts are preferred. As the quaternary ammonium salts, compounds represented by the following general formula (I) are preferable.

[0015]

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In the formula, R ₁ represents an alkyl group, alkenyl group or alkynyl group having 6 to 22 carbon atoms, and R ₂ represents an alkyl group, alkenyl group or alkynyl group having 1 to 6 carbon atoms. R ₃ , R ₄ , and R ₅ may be the same or different;
Represents an aliphatic group, an aromatic group, or a heterocyclic group. The aliphatic group means a linear, branched or cyclic alkyl group, alkynyl group, or alkenyl group. The aromatic group represents a benzene monocyclic or condensed polycyclic aryl group. These groups may have a substituent such as a hydroxyl group. A represents an amide bond, an ether bond, an ester bond, or a phenyl group, but may not be present. X ^- is halogen, nitrate ion, represents a sulfate ion, these ions may have substituents.
As a specific compound

[0017]

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[0018]

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The amount of the antistatic agent used is 1 mg / m ^{2 to} 50 mg /
m ² , and the optimum surface resistance range is 10 ¹⁰ Ω / □ to 10 ¹²
Ω / □. The antistatic agent may be used by mixing with the transparent resin, or may be overcoated on the transparent resin layer. The amount used depends on which one you choose.

Further, the transparent resin is a carboxylic acid comprising a bisphenol derivative represented by the general formula (II) or a substituted derivative thereof as a diol component and a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof. A polyester resin containing at least a component is preferred.

[0021]

Embedded image

(Wherein R is an ethylene or propylene group,
x and y are each a positive integer of 1 or more, and x + y
The average value is 2-10. )

Compatibility with the binder resin of the toner means that the transparent resin and the binder resin of the toner do not form a boundary in the image after fixing. As a method for evaluating the compatibility of the toner with the binder resin, a solubility parameter is used in Japanese Patent Application Laid-Open No. Hei 2-263624, but the method for evaluating the compatibility during heat fixing is as follows. However, it has become clear from studies by the inventors that this is not always preferable. As a method for correctly evaluating the compatibility of a toner with a binder resin, the present inventors have found a new evaluation scale called “molten toner inclination angle”. The method for measuring the “melt toner inclination angle” will be described below.

(Method of Measuring Tilt Angle of Fused Toner) A toner disk is formed. Hand press SSP for tablet press manufactured by Shimadzu Corporation
A 10-shaped tablet frame (see FIG. 2) having a concave shape with a diameter of 13 mm and a height of 33 mm is filled with powdered toner, and a 1-ton weight is applied by a hand press for 1 minute to form a toner disk. At this time, the standard size of the toner disk is 13 mm in diameter, 1.2 mm in thickness, and 0.183 g in weight. (See Fig. 3)

Melt Solidification of Toner A transfer target film and a toner disk set at a set temperature are placed as shown in FIG. 4, and the toner disk is melted for one minute (for example, when the fixing roll is heated at 150 ° C. When the temperature of the transfer film transparent resin layer is 100 ° C.,
Measure at 100 ° C. ). FIG. 4 illustrates this case, and shows a state in which the transfer target film 62 and the toner disk 61 are mounted on the hot plate 63. Thereafter, the plate is placed on an aluminum plate having a thickness of 5 mm and a size of 420 mm × 297 mm for 1 minute, quenched and solidified.

Measurement of Melt Toner Inclination Angle Using a contact angle measuring device manufactured by Kyowa Interface Chemical Co., Ltd., the angle of the foot of the toner after the toner is solidified is measured twice, and the average value thereof is used to determine the melt toner inclination angle. To be

When a transparent resin is selected from the viewpoint of the molten toner inclination angle, it is preferable to use a resin having a toner inclination angle of 40 degrees or less between the toner used for color image formation and the film. As the resin of the transparent resin layer in which the molten toner inclination angle becomes 40 degrees or less, polyester resin, styrene-acryl ester resin, epoxy resin, polyurethane resin,
Thermoplastic resins such as polymethyl methacrylate resin, vinyl chloride resin, and vinyl chloride-vinyl acetate copolymer can be used. Particularly preferred is a resin of the same type as the main resin of the toner (a resin contained at 50% by weight or more based on the binder resin). That is, if the main resin of the toner is a polyester resin, a polyester resin is used as the resin of the transparent resin layer, and if the main resin of the toner is a styrene-acryl ester resin, a styrene-acryl ester resin is used as the resin of the transparent resin layer. preferable.

The important characteristics of the resin in the transparent resin layer are that the inclination angle of the molten toner is not more than 40 degrees and the apparent melt viscosity at the fixing temperature is lower than that of the binder resin of the toner. The apparent melt viscosity is determined as follows. That is, a flow tester CFT-500A manufactured by Shimadzu Corporation was used, and a die (nozzle) having a diameter of 0.5 mm and a thickness of 1.0 mm was used for 100 k.
g of extrusion load, the initial set temperature was 80 ° C., the preheating time was 300 seconds, and the apparent melt viscosity was measured at each temperature when the temperature was raised at a constant speed of 5 ° C./min. The apparent melt viscosity at the fixing temperature of the transparent resin layer,
The apparent melt viscosity at the fixing temperature is used. (For example,
When the fixing roll was 150 ° C. and the surface temperature of the film to be transferred was fixed at 100 ° C., the apparent melt viscosity at 100 ° C. was defined as the apparent melt viscosity at the fixing temperature. )

Fixing temperature 1 required for resin of transparent resin layer
The apparent melt viscosity at 00 ° C. varies depending on the melt viscosity of the toner used. However, when a sharp melt toner is used in the color image forming method, the apparent melt viscosity is 1 × 10 ^{3 to} 7 ×.
Those having 10 ⁴ poise, preferably 5 × 10 ³ to 4 × 10 ⁴ poise are used. As the resin of the transparent resin layer, the apparent melting temperature at 100 ° C. is 1 × 10
^When a resin having less than ³ poises is used, the transparent resin layer is undesirably peeled off from the plastic film when the toner image is fixed by a heat roll. On the other hand, when a resin having an apparent melt viscosity of more than 7 × 10 ⁴ poise at a temperature of 100 ° C. is used as the resin for the transparent resin layer, the toner image is fixed on the transparent resin layer even when the toner image is fixed with a heat roll. The degree of sinking is extremely small, the projected image has low saturation, and a pseudo contour occurs. The optimum thickness of the transparent resin layer depends on the particle size of the toner to be fixed.
The range is preferably from 8 to 8 μm.

Next, a method for producing the electrophotographic transfer film of the present invention will be described. Alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, methylene chloride, ethylene chloride,
A resin for forming a transparent resin layer is dissolved in one or more mixed organic solvents of chlorinated hydrocarbons such as tetrachloroethane, and an antistatic agent is added in an amount of 0.01% to 5%.
%, And applied on a plastic film by a coating method such as a bar coating method, a dipping method, a spraying method, and a spin coating method, and dried. When applying the transparent resin layer on the plastic film, a swelling agent for the plastic film may be used, if necessary, to increase the adhesive strength between the transparent resin layer and the plastic film.

As a swelling agent for a plastic film,
Phenol, resorcinol, orthochlorophenol, parachlorophenol, cresol and other phenol derivatives and benzoic acid, salicylic acid, salicylic acid ester, monochloroacetic acid, trichloroacetic acid, trifluoroacetic acid,
2-nitropropanol, benzyl alcohol, benzaldehyde, acetonylacetone, acetophenone, benzamide, benzonitrile, methyl nicotinate and the like. The amount of these swelling agents is 2 to 1 of the total solvent in weight ratio.
0% is appropriate.

The transparent resin layer may contain a matting agent for adjusting the coefficient of friction between films, if necessary. Examples of the matting agent include fine particles such as silica, starch, and alumina, and plastic powders such as polyethylene, polyester, polyacrylonitrile, and polymethyl methacrylate. The amount of matting agent used is
The range is preferably from 0.1% by weight to 10% by weight based on the resin used.

Next, the toner used in the electrophotographic transfer film of the present invention will be described. A toner used in a color electrophotographic apparatus needs to have good melting property and color mixing property when heat is applied, and has a low softening point, a low apparent melt viscosity at a fixing temperature, and a sharp melt property toner. It is preferred to use. In relation to the transparent resin layer of the electrophotographic transfer film described above, the binder resin of the toner has an apparent melt viscosity that is clearly greater than the apparent melt viscosity of the resin forming the transparent resin layer. Is preferred. Specifically, the binder resin of the toner has an apparent melt viscosity of 8 × 10 ^{4 to} 3 × at a temperature of 100 ° C.
It is preferably 10 ⁵ poise, and more preferably 9 × 10 ⁴ to 2 × 10 ⁵ poise, in view of compatibility with the electrophotographic transfer film and color mixing between toners.

The toner is manufactured by melt-kneading, pulverizing and classifying a toner-forming material such as a binder resin such as a polyester resin or a styrene-acryl ester resin, a colorant (dye, a sublimable dye), and a charge control agent. Is done. If necessary, an external addition step of adding various external additives (for example, hydrophobic colloidal silica) to the toner may be added.

In the color toner, the same type of resin as the resin in the transparent resin layer, that is, a bisphenol derivative represented by the above formula (I), or a substituted product thereof is used as a binder resin in consideration of fixability and sharp meltability. Ingredients
A polyester resin containing at least a carboxylic acid component comprising a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof is preferred. The softening point of the polyester resin is 75 to 150 ° C, preferably 80 to
A range of 120 ° C. is preferred. In relation to the toner and the electrophotographic transfer film, the temperature of the binder resin of the toner 1
The binder resin is selected and used so that the apparent melt viscosity at 00 ° C. is clearly higher than the apparent melt viscosity of the transparent resin of the transferred film at a temperature of 100 ° C.

Next, a color image forming method will be described. FIG. 1 is a schematic cross-sectional view of an electrophotographic apparatus capable of forming a full-color image used in the present invention. The electrophotographic apparatus includes a transfer material transport system provided from a lower side of the apparatus main body (lower side in FIG. 1) to a substantially central portion of the apparatus main body, and a transfer material transport system provided at a substantially central portion of the apparatus main body. The latent image forming unit is provided in the vicinity of the transfer drum 10 and the developing device is provided in the vicinity of the latent image forming unit.

The transfer material transport system includes supply trays 15 and 16 formed on the lower side of the apparatus main body, and paper feed rollers 17 and 1 disposed almost directly above the respective trays.
8, paper feed guides 19 and 20 disposed close to these paper feed rollers, and a transfer material separation charger 21 provided near the paper feed guide 20 and near the outer peripheral surface. And the transfer device 11 and the electrode 2
A transfer drum 10 on which a transfer roller 4 is disposed and which is rotatable in the direction of the arrow.
And a contact roller 23 in contact with the outer peripheral surface thereof, a conveying device 13, a fixing device 14 disposed close to the end of the conveying device in the conveying direction, and a detachable discharge tray 2.
And 2.

The outer peripheral surface of the latent image forming section is
An electrostatic latent image holding member (photosensitive drum) 1 which is disposed in contact with the outer peripheral surface of the photosensitive drum 0 and is rotatable in the direction of an arrow;
A charger 8 disposed near the outer peripheral surface of the electrostatic latent image carrier; and an image exposure device such as a laser beam scanner for forming an electrostatic latent image on the outer peripheral surface of the electrostatic latent image carrier. A writing unit 9 having a unit and an image exposure / reflection unit such as a polygon mirror, and a cleaning unit 12 are provided.

The developing device comprises a developer carrier 7 and a housing 6, and is formed on the outer peripheral surface of the electrostatic latent image holder at a position facing the outer peripheral surface of the electrostatic latent image holder 1. Black developing machine 2, magenta developing machine 3, cyan developing machine 4 for visualizing (ie, developing) the formed electrostatic latent image
And a yellow developing machine 5.

The sequence of image formation by the electrophotographic apparatus having the above configuration will be described by taking a full color mode as an example. When the electrostatic latent image carrier 1 described above rotates in the direction of the arrow, the surface of the electrostatic latent image carrier is charged by the charger 8.
Is charged uniformly. When uniform charging is performed by the charger 8, an electrostatic latent image is formed on the electrostatic latent image holder 1 through the writing device 9 by a laser beam modulated by a black image signal of a document (not shown). Then, the electrostatic latent image is developed by the black developing machine 2. On the other hand, from the supply tray 15 or 16 to the paper feed roller 17 or 1
8. The transfer material conveyed via the paper feed guide 19 or 20 is applied to the electrode 2 facing the contact roller 23.
4 electrostatically winds the transfer drum 10.
The transfer drum 10 rotates in the direction of the arrow in synchronization with the electrostatic latent image holder 1, and the developed image developed by the black developing device 2 is transferred to the outer peripheral surface of the electrostatic latent image holder 1 and the transfer drum 10. The image is transferred by the transfer device 11 at a portion where the outer peripheral surface is in contact. The transfer drum 10 continues to rotate as it is to prepare for the transfer of the next color (magenta in FIG. 1).

On the other hand, the electrostatic latent image holder 1 is neutralized by a neutralizing charger (not shown), is cleaned by a cleaning device 12, is charged again by the charger 8, and is charged by the next magenta image signal. It receives the latent image light as described above. The electrostatic latent image formed by image exposure based on the magenta image signal is developed by the magenta developing device 3 to become a visible image. Subsequently, the above-described process was performed for cyan and yellow, respectively,
When the transfer of the colors is completed, the multicolored visible image formed on the transfer material is neutralized by the charger 21 and sent to the fixing device 14 by the paper conveying device 13 and is fixed by heat and pressure to form a series of full-color images. The formation sequence ends.

The main part of the fixing device 14 is composed of a heat roll 14a and a pressure roll 14b having the same structure. The heat roll 14a has 50 inside.
A substrate roll provided with a 0 W Colts lamp and formed of a steel core material having an outer diameter of 44 mmφ, and a rubber provided on the substrate roll through an appropriate primer with a rubber hardness of 60 ° in JIS hardness and a thickness of 40 μm (For example, Viton rubber manufactured by DuPont). On the other hand, the pressure roll has the same configuration, and uses a substrate roll formed of a steel core material having an outer diameter of 48 mmφ and an inner elastic layer having a thickness of 1 mm made of silicon rubber provided on the substrate roll. Except for, the configuration is exactly the same.

The heat roll is supplied with a release agent composed of dimethylpolysiloxane containing a functional group (for example, an amino group) in order to modify the surface of the fluoro rubber into a high release surface. As a means, an oil donor roll made of silicone rubber is in contact. The oil donor roll is supplied with a release agent by an oil pickup roll immersed in an oil pan. The heat roll 14a and the pressure roll 14b are pressed against each other by a pressing mechanism, and are 6 mm in the center.
Nip width is formed. Further, both rolls are configured such that the surface temperature is set at 150 ° C., and the rolls rotate at a surface speed of 60 mm / sec in the direction of the arrow.

[0044]

EXAMPLE 1 100 ° C. on a 100 μm thick polyester film having a heat distortion temperature of 152 ° C. and a maximum operating temperature of 150 ° C.
A polyester resin D apparent melt viscosity is a polyester resin C, 7 × 10 ⁴ poises is a polyester resin B, ⁴ × 10 4 poises is a polyester resin A, 5 × 10 ³ poise is 1 × 10 ³ poise at Each solution dissolved in methyl ethyl ketone was applied by a bar coater method, and the thickness after drying was 0.5 μm, 1 μm,
A transparent resin layer is formed to have a thickness of 2 μm, 8 μm, and 20 μm, and the electrophotographic transfer films FA, FB, FC, F
D was obtained. Polyester resin A is bisphenol A40
%, Fumaric acid 10%, isopropylene glycol 50
B is a composition of 25% by weight of a bisphenol derivative, 22% by weight of fumaric acid, 53% by weight of isopropylene glycol, C is 23% of terephthalic acid,
Bisphenol A 27%, isopropylene glycol 5
The composition is 0%, and D is a copolymer having a composition of 35% terephthalic acid, 15% bisphenol A, and 50% isopropylene glycol. Transfer film F for electrophotography
In A, FB, FC, and FD, 1% by weight of polymethyl methacrylate was added to the polyester resin as a matting agent.

The apparent melt viscosity at 100 ° C. is 1 ×
10 ⁵ poise polyester resin PT (solubility parameter about 11) negative charge inhibitor 1 part by weight to 96 parts by weight, the addition of cyan pigment 3 parts by weight, to prepare a cyan toner. Similarly to the cyan toner, 96 parts by weight of a polyester resin,
A magenta toner was prepared by adding 3 parts by weight of a magenta pigment to 1 part by weight of the negative charge inhibitor, a yellow toner was prepared by adding 3 parts by weight of a yellow pigment, and a black toner was prepared by adding 3 parts by weight of a black pigment. The volume average particle diameter of these cyan, magenta, yellow and black toners was 7 μm. The measurement of the volume average particle diameter of the toner is carried out using a Coulter Counter TA-II type (manufactured by Coulter),
The particle size distribution of particles having a particle size of 2 to 50 μ was measured using an aperture of μ to determine the volume average particle size.

Using the electrophotographic transfer film and the color toner obtained by the above method, the electrophotographic apparatus shown in FIG. 1 is used to superimpose four colors of cyan, magenta, yellow and black on the transfer film. The toner weight is 2
A full-color unfixed toner image of mg / cm ² was formed. The full-color unfixed toner image is heated to a fixing temperature of 15 ° C.
Fixing by heating and pressing under the conditions of 0 ° C. and an average heating time of 100 msec to form a full-color fixed image on the transfer-receiving film,
The lightness, saturation, and pseudo contour of the OHP projection image were evaluated. Further, the surface electric resistance was measured. Furthermore, the presence / absence of generation of discharge marks and the degree of retransfer were evaluated. At the same time, the degree of fixation of the full-color toner (including a decrease in the degree of fixation due to peeling of the transparent resin layer from the plastic film) was also evaluated.

The evaluation of the lightness and the saturation of the OHP projection area is based on the tristimulus values X of the projected colors based on JIS Z8722.
Y and Z are converted to CIE1976 (L ^* a ^* b ^* ) color space, and lightness (L ^* ) and saturation

[0048]

(Equation 1)

Was evaluated. For the measurement of the spectral transmittance, a spectrophotometer was used, the light source was standard light A, and the color matching function was the value of a 2 degree field of view. The evaluations of the lightness L ^* and the saturation C ^* are as follows: input halftone dot area ratio 100% (CiN 100%), 50% (CiN 50
%), And outputs L ^* and C ^{* of the} shadow color ^.
Was measured. (Evaluation was also performed for other colors, but similar results were obtained, so only the cyan result is shown.) For the pseudo contour, a natural image of a person or the like is created on an OHP film, and the natural image is created using OHP. The degree of the pseudo contour generated in the image when projected on the screen was visually evaluated. The degree of the discharge mark and the degree of retransfer were visually evaluated by outputting a patch in which the input halftone dot area ratio was continuously changed and using an OHP to project the patch on the image when projected. The surface electric resistance was measured with an insulation resistance measuring instrument VE-30 (manufactured by Kawaguchi Electric).

The fixing degree was evaluated by the following method. Using a cloth or the like, cleanly remove the fuser oil adhering to the transfer-receiving film on which the color image has been fixed. Cellophane tape (Nichiban CT-18) on the fixed image
Paste. Peel off the cellophane tape. (Peel angle: 180 degrees,
Peeling time: 1 sec) The peeling state of the image area after the cellophane tape peeling is visually evaluated. Tables 1 and 2 show the evaluation results.

[0051]

[Table 1]

[0052]

[Table 2]

Notes: 1) Grade of pseudo contour: 1 ... No occurrence. 2: Almost no occurrence. 3: Acceptable level. 4: It has occurred considerably. 5: Very many occurrences. 2) Grade after fixing: 1 ... No image peeling. 2: It is hardly peeled off.
3: Acceptable level. 4: It peels off considerably. 5: Very much peeling. 3) Grade of peeling of transparent resin layer due to film bending 1: No transparent resin layer peeling. 2: Almost no peeling. 3: Acceptable level. 4: It peels off considerably. 5: Very much peeling.

Tables 1 and 2 do not describe surface electric resistance, discharge marks, and retransfer. At all levels, the surface electric resistance was higher than 10 ¹⁵ Ω / □, discharge marks were generated, but no retransfer was generated. From Table 1, it is clear that when a resin having an apparent melt viscosity clearly lower than the toner binder resin at the toner fixing temperature and having a molten toner inclination angle of 40 degrees or less at the toner fixing temperature is used for the transparent resin layer, the transparent resin When the thickness of the layer is in the range of 1 μm to 8 μm,
It can be seen that a full-color image with less occurrence of false contours, good lightness and chroma, excellent fixation, and little peeling of the transparent resin layer due to film bending is obtained. The apparent melt viscosity at the fixing temperature of the transparent resin layer is 1 ×
10 ³ poise to 7 × 10 ⁴ poise is preferable, and when the apparent melt viscosity is 5 × 10 ³ poise to 4 × 10 ⁴ poise, it can be understood that it is particularly preferable in terms of pseudo contour. The thickness of the transparent resin layer is preferably 1 μm to 8 μm,
If the thickness is less than 8 μm, a large number of pseudo contours are generated. It can be understood that the thickness of the transparent resin layer is particularly preferably 2 μm to 8 μm from the viewpoint of pseudo contour.

Next, on a polyester film having a thickness of 100 μm and a heat distortion temperature of 152 ° C. and a maximum operating temperature of 150 ° C., the polyester resin B of Example 1 was charged with a matting agent and an anionic alkylbenzene sulfonate soda. The surface electric resistance was changed depending on the amount of the agent to be added, to obtain an electrophotographic transfer film FE having a dried resin layer having a thickness of 2 μm. Similarly, a transfer film FF for electrophotography was obtained in which the surface electric resistance was changed using cationic stearaside propylene dimethyl-β-hydroxyethylammonium nitrate as an antistatic agent. Using the same color toner as above, a full-color fixed image was formed on the transfer-receiving film in the same manner as above, and the discharge marks and retransfer on the OHP projected image were evaluated. Table 3 shows the evaluation results.

[0056]

[Table 3]

As can be seen from Table 3, in the case of the anionic alkylbenzenesulfonic acid-based antistatic agent, retransfer occurs at 10 ¹⁰ Ω or less, and the range of the optimum surface electric resistance value at which neither discharge marks nor retransfer can be prevented is extremely large. I can understand that it is narrow. By using a cationic antistatic agent, this range can be expanded.

COMPARATIVE EXAMPLE 100 ° C. on a polyester film having a heat distortion temperature of 152 ° C. and a maximum operating temperature of 150 ° C.
Polyester resin G having an apparent melt viscosity of 2 × 10 ⁴ poise (Vylon GK150, manufactured by Toyobo Co., Ltd.), and polyester resin H having an apparent melt viscosity of 8 × 10 ⁵ poise (Vylon 200: 24.2% terephthalic acid, isophthalic acid) (26.3% of acid, 22.1% of ethylene glycol, and 27.2% of neopentyl glycol) in methyl ethyl ketone are applied by a bar coater method, and the thickness after drying is 1 μm, 2 μm, and 8 μm. A transparent resin layer is formed on the transfer film F for electrophotography.
G and FH were obtained. The matting agent was added in the same manner as in Example 2. A cationic antistatic agent was added in an amount of 15 mg / m ^2, and the surface electricity prevention was set to 10 ¹¹ Ω. Using the same color toner as in Example 1, a full-color fixed image was formed by the same method, and evaluation was performed by the same method as in Example 1.
Table 4 shows the evaluation results.

[0059]

[Table 4]

From Table 4, it is clear that the apparent melt viscosity at the toner fixing temperature is clearly higher than that of the toner binder resin and that the molten toner inclination angle at the toner fixing temperature is larger than 40 degrees. Film FH is
The occurrence of pseudo contours was remarkably large, and the brightness and the saturation were also reduced, so that a preferable full-color projected image could not be obtained. A transfer film FG using a resin having an apparent melt viscosity lower than that of a toner binder resin at a toner fixing temperature but having a melt toner inclination angle larger than 40 degrees in a toner fixing temperature.
Is similar to FH in that the occurrence of false contours is remarkably large, and the brightness,
The saturation was also reduced, and a favorable full-color projected image could not be obtained.

[0061]

The transfer film for electrophotography of the present invention is
Since the transparent resin layer having the above configuration is provided, it is excellent in fixing property of a full-color image, and by a color image forming method by an electrophotographic method, lightness and chroma are high, color tone reproducibility is good, It is possible to easily form a full-color projection image in which no false contour occurs.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an electrophotographic apparatus used for forming a color image on an electrophotographic transfer film of the present invention.

FIG. 2 is a cross-sectional view of a tablet frame for forming a toner disk used for measurement of a tilt angle of a molten toner.

FIG. 3 is a perspective view of a formed toner disk used for measuring a molten toner inclination angle.

FIG. 4 is a schematic cross-sectional view of an apparatus for fusing and solidifying a toner disk used for measuring a molten toner inclination angle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrostatic latent image holding body 2 ... Black developing machine 3 ... Magenta developing machine 4 ... Cyan developing machine 5 ... Yellow developing machine 8 ... Charging device 9 ... Writing device 10 ... Transfer drum 11 ... Transfer device 12 ... Cleaning device 13 ... Conveying device 14 ... Fixing device 14a ... Heat roll 14b ... Pressure roll 15,16 ... Supply tray 17, 18 ... Supply roller 19,20 ... Supply guide 21 ... Electrifier 22 ... Eject tray 23 ... Abutment roller

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 7/00 A G03G 7/00 B

Claims (3)

(57) [Claims] 1. An electrophotographic transfer film used in an electrophotographic system in which a charged toner is adsorbed on an electrostatic latent image holding member and is transferred onto a transfer film, a plastic film having a heat resistance temperature of 100 ° C. or higher. at least one surface, bets
Lower apparent melt viscosity than toner binder resin, and toner
Transparent with a tilt angle of molten toner of 40 degrees or less at the fixing temperature
An electrophotographic transfer film provided with a layer containing a resin . 2. A plastic film having a heat-resistant temperature of 100 ° C. or higher in an electrophotographic transfer film used in an electrophotography system in which a charged toner is adsorbed on an electrostatic latent image holding member and is transferred onto the transfer film. Heat on at least one side of
On a layer containing an antistatic agent having a charge opposite to that of the thermoplastic resin and the toner, or on a layer containing the thermoplastic resin
And a layer containing the above antistatic agent . 3. A plastic film having a heat-resistant temperature of 100.degree. C. or more in an electrophotographic transfer film used in an electrophotographic system in which a charged toner is adsorbed on an electrostatic latent image holding member and is transferred onto the transfer film. At least on one side, the angle of inclination of the molten toner with the toner to be fixed at the fixing temperature of the toner is 40 degrees or less, and the apparent melting temperature at 100 ° C. is 1 × 10 ^{3 to} 7 × 10 ⁴ poise. A layer containing a transparent thermoplastic resin and a cationic antistatic agent, or a layer containing a thermoplastic resin.
A transfer film for electrophotography, comprising a layer containing an antistatic agent .