JP2005092097A - Transferred body for color electrophotographic image and color electrophotographic image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transferred body for a color electrophotographic image with which an image is produced of high image quality having a uniform gloss on the entire image surface like a silver salt photograph and also having high mechanical strength with low energy consumption without spoiling heat resistance, and to provide a color electrophotographic image forming method. <P>SOLUTION: The transferred body for a color electrophotographic image has a toner receiving layer formed from a crystalline polyester resin, wherein the crystalline polyester resin includes an aromatic dicarboxylic acid component as an acid-originated constituent in an amount of ≥90 mol% based on all acid-originated constituents, a linear aliphatic diol as an alcohol-originated constituent in an amount of 90-99 mol% based on all alcohol-originated constituents, and bisphenol S or an alkylene oxide adduct of bisphenol S in an amount of 2-15 mol% based on allalcohol-originated constituents. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color electrophotographic image transfer object and a color electrophotographic image forming method using the same.

Japanese Patent Laid-Open No. 4-242752 JP-A-5-197184 JP 2000-10329 A

  For example, color image formation in the electrophotographic system is performed as follows. That is, based on digital color image data, image signals of a plurality of colors obtained by performing image processing and color correction with an image processing apparatus are converted into laser beams for each color, and these laser beams are applied to an inorganic or organic photoreceptor several times for each color. Irradiation forms a plurality of electrostatic latent images, and the plurality of electrostatic latent images are sequentially developed with color toner. The developed toner image is transferred from the photosensitive member to a transfer material such as paper or film, and is heat-fixed by a heat fixing roll or the like to form a color image on the transfer material.

  In this case, as the color toner, for example, particles in which a colorant is dispersed in a binder resin such as a polyester resin or a styrene / acrylic copolymer are used (Patent Document 1).

  In addition, as the material to be transferred, plain paper mainly composed of pulp raw materials, coated paper in which white pigment is mixed with resin on plain paper, white film in which white pigment is mixed in resin such as polyester, etc. Used. When an image having excellent full-color reproducibility is to be produced, good image quality cannot be obtained if inexpensive plain paper is used. As described in Patent Document 2, etc., plain paper, coated paper, or white film Is used as a base and is provided with a transparent resin layer made of a thermoplastic resin.

  Furthermore, a transfer paper having a transfer layer containing an aromatic polyester resin has been proposed for the purpose of sufficiently reducing the unevenness of the toner image during printing and obtaining a clear image (Patent Document 3).

  Here, considering the reduction of energy consumption in image production, low-temperature fixability is an essential issue, but in order to satisfy this low-temperature fixability, the glass transition point of the resin of the transferred layer is lowered, the molecular weight is reduced. Making it small is an effective means.

  On the other hand, an image with a smooth surface such as a photograph is stored in a car in the summer or in a warehouse, with the image surface and back surface, image surfaces overlapping each other, image surface and album material, etc. If left in a high-temperature environment such as transport, the problem of blocking (the surface cannot be peeled off or the surface is damaged even if it is peeled off) arises. In order to improve durability at high temperatures, that is, heat resistance, it is effective to increase the glass transition point of the resin of the transferred layer and increase the molecular weight.

  Furthermore, an improvement in durability when the image is bent, that is, improvement in mechanical strength is also an important issue. To increase the mechanical strength, increasing the molecular weight and increasing the flexibility of the resin are effective solutions.

  That is, the improvement direction of mechanical strength and heat resistance is contrary to the improvement direction of low-temperature fixability. In particular, when making an image with a gloss as high as that of silver halide photographic prints, the fixing temperature needs to be higher, making it more difficult to satisfy all three requirements.

  Further, when the main component of the thermoplastic resin layer is a conventionally used crystalline resin such as polyester, a resin satisfying low-temperature fixability, heat resistance and mechanical strength can be produced. The image output from the fixing device is not solidified, the surface of the image is not smooth, uneven glossiness, or the image is stuck to the belt even after passing the peeling roll and cannot be peeled off. This causes the problem.

  Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its object is to have a uniform high gloss on the entire surface of the image as in a silver salt photograph and to have a mechanical strength. An object of the present invention is to provide a color electrophotographic image transfer material and a color electrophotographic image forming method capable of producing a high-quality image with a small energy consumption without impairing heat resistance.

  The inventors of the present invention have used a color electrophotographic image transfer material formed by coating a specific polyester resin to form a toner receiving layer, so that a toner image can be uniformly formed into a toner receiving layer at a fixing temperature lower than before. It is possible to embed, eliminate the step with the paper surface, obtain a high-quality image of silver salt photographic tone, and not to cause damage due to mechanical force such as cracking due to folding and bending during handling. The headline and the present invention were completed.

That is, the present invention described in claim 1 is a color electrophotographic image transfer member provided with a toner receiving layer formed of a crystalline polyester resin,
The crystalline polyester-based resin contains an aromatic dicarboxylic acid component as an acid-derived constituent component in an amount of 90 mol% or more based on the total acid-derived constituent component, and a linear aliphatic diol as an alcohol-derived constituent component. In contrast, 90 mol% or more and 99 mol% or less is included, and bisphenol S or bisphenol S alkylene oxide adduct is included in the range of 2 mol% or more and 15 mol% or less with respect to all alcohol-derived components. This is a color electrophotographic image transfer member.

  The invention according to claim 2 is characterized in that the crystalline polyester resin has a melting point Tm of 80 ° C. or more and 110 ° C. or less, and is transferred to a color electrophotographic image according to claim 1. Is the body.

  The color electrophotographic image according to claim 1 or 2, wherein the straight chain aliphatic diol is a straight chain aliphatic diol having 6 to 12 carbon atoms. It is an object to be transferred.

  In the invention according to claim 4, the acid-derived component of the crystalline polyester resin is mainly an aromatic dicarboxylic acid derived from terephthalic acid, 2,6-naphthalenedicarboxylic acid, or 4,4′-biphenyldicarboxylic acid. The color electrophotographic image transfer object according to claim 1, wherein the transfer object is a component.

  The invention according to claim 5 is the color electrophotographic image transfer object according to any one of claims 1 to 4, wherein the crystalline polyester resin has a weight average molecular weight of 15000 to 50000. is there.

  The invention described in claim 6 is characterized in that when the crystalline polyester resin is formed into a film having a thickness of 20 μm, the luminous reflectance Y of the film is 1.5% or less. Or a color electrophotographic image transfer member according to any one of the above.

  The invention according to claim 7 is characterized in that the toner receiving layer contains 3 to 15% by mass of inorganic fine particles, and the color electrophotographic image transfer object according to any one of claims 1 to 6. It is.

  The invention according to claim 8 is the color electrophotographic image transfer object according to claim 7, wherein the inorganic fine particles are titanium dioxide or silica having a particle diameter of 8 to 200 nm.

  The invention according to claim 9 is a color according to any one of claims 1 to 8, comprising a support, a light scattering layer on the support, and the toner receiving layer on the light scattering layer. An electrophotographic image transfer object.

The invention according to claim 10 is characterized in that the light scattering layer is formed of a polyolefin-based thermoplastic resin having a temperature Tb of 115 ° C. or more at which the viscosity becomes 5 × 10 ³ Pa · s. The color electrophotographic image transfer member according to claim 9.

  The invention according to claim 11 is the color electrophotographic image transfer object according to claim 9 or 10, wherein the light scattering layer contains 20 to 40% by mass of a white pigment.

The basis weight of the support is 100 to 250 g / m ² , the thickness of the light scattering layer is 20 to 50 μm, and the thickness of the toner receiving layer is 5 to 20 μm. The color electrophotographic image transfer object according to claim 9, wherein the transfer object is a color electrophotographic image transfer object.

  The invention according to claim 13 is characterized in that a gelatin layer is provided between the light scattering layer and the toner receiving layer, and the color electrophotographic image transfer object according to any one of claims 9-12. It is.

  The invention described in claim 14 is the color electrophotographic image transfer object according to any one of claims 1 to 13, further comprising an antistatic layer on the front surface and / or back surface thereof.

Furthermore, the invention described in claim 15 transfers a toner image made of color toner onto a transfer medium, and fixes the toner image on the transfer medium by heating and pressurizing the toner image superimposed on a fixing belt. A color electrophotographic image forming method for peeling the toner image from the fixing belt after cooling from 30 ° C. to 80 ° C.,
The transferred object is a transferred object for a color electrophotographic image according to any one of claims 1 to 14.
In the color toner, a colorant is dispersed in a binder resin. The main component of the binder resin is a temperature Tm ′ at which the viscosity becomes 1 × 10 ⁴ Pa · s, and a melting point Tm of the crystalline polyester resin. The above is a color electrophotographic image forming method characterized by being a polyester-based or styrene-acrylic thermoplastic resin having a Tm of less than 20 ° C.

  According to the present invention, a color electrophotographic image-forming transfer material that is excellent in all of high glossiness, mechanical strength, heat resistance, and low-temperature fixability, has a fast solidification speed, high overall image quality, and provides a preferable image. Can be provided.

  Further, according to the present invention, it is possible to provide a color electrophotographic image forming method for producing a preferable image using such a transferred material.

[Transfer for color electrophotographic image]
The toner receiving layer, support, light scattering layer, and other layers suitable for constituting the color electrophotographic image transfer material of the present invention will be described in detail below.

(Toner receiving layer)
In the color electrophotographic image transfer object of the present invention, the toner-receiving layer is formed of a crystalline polyester resin, and the crystalline polyester resin has an aromatic dicarboxylic acid component as an acid-derived constituent component. 90 mol% or more with respect to the component, linear aliphatic diol as the alcohol-derived component in a range of 90 mol% or more and 99 mol% or less with respect to the component derived from all alcohols, and bisphenol S or bisphenol The S alkylene oxide adduct is contained in the range of 2 mol% or more and 15 mol% or less with respect to all alcohol-derived components.

  The crystalline polyester resin preferably contains a bisphenol S alkylene oxide adduct as an alcohol-derived constituent component in a range of 2 mol% or more and 15 mol% or less with respect to the total alcohol-derived constituent component. More preferably, it is contained in the range of 10 mol% or less. When the content of bisphenol S or bisphenol S alkylene oxide adduct exceeds 15%, plasticization of the resin occurs and heat resistance is impaired. Moreover, it is more preferable that linear aliphatic diol is included in the range of 95 mol% or more and 98 mol% or less with respect to all alcohol-derived components as an alcohol-derived component. Moreover, you may copolymerize a 3rd component as needed, such as melting | fusing point adjustment.

  Examples of the acid-derived constituent component include various aromatic dicarboxylic acids, such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, or lower alkyl esters and acid anhydrides thereof. Is mentioned. It is preferable that an aromatic dicarboxylic acid derived from terephthalic acid, 2,6-naphthalenedicarboxylic acid, or 4,4'-biphenyldicarboxylic acid is a main component. Among these, terephthalic acid is preferable because it is easily available and a polymer having a low melting point is easily formed.

  Moreover, an aromatic component can be 90 mol% or more as an acid origin component of crystalline polyester, and aliphatic dicarboxylic acid can be used as another acid origin component. For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof And acid anhydrides. Among these, considering availability, sebacic acid and 1,10-decanedicarboxylic acid are preferable.

  In the crystalline polyester resin forming the toner receiving layer, the linear aliphatic diol is preferably a linear aliphatic diol having 6 to 12 carbon atoms.

  Specific examples of the aliphatic diol include 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1, Examples thereof include 11-undecanediol and 1,12-dodecanediol. Considering availability, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable, and 1,9-nonanediol is particularly preferable from the viewpoint of a low melting point.

  The melting point Tm of the crystalline polyester resin as the main component of the toner receiving layer is preferably 80 ° C. or higher and 110 ° C. or lower. More preferably, it is 80-100 degreeC, Most preferably, it is 85-95 degreeC. When the temperature is less than 80 ° C., the heat resistance is low, and if left at a high temperature, problems such as blocking are likely to occur. If the temperature exceeds 110 ° C., it is difficult to obtain a smooth and glossy image surface by fixing, and even on the fixed image surface, a step is likely to remain at the boundary between the high density portion and the low density portion.

  Here, “crystallinity” of “crystalline polyester-based resin” means that it has a clear endothermic peak, not a stepwise endothermic change, in an analysis using a differential scanning calorimeter (DSC). Point to. DSC was used for measuring the melting point Tm of the crystalline polyester resin, and the top value of the endothermic peak was defined as the melting point Tm at a rate of temperature increase of 10 ° C. per minute from 0 ° C. to 150 ° C.

  When the main component of the toner receiving layer is an amorphous resin, it is difficult to satisfy all of low-temperature fixability, heat resistance, and mechanical strength.

  The weight average molecular weight of the crystalline polyester resin forming the toner receiving layer is preferably 15000 to 50000, and more preferably 17000 to 40000.

  The crystalline polyester resin forming the toner receiving layer may be one type or a mixture of a plurality of different crystalline polyester resins.

  The crystalline polyester resin used for the toner receiving layer can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. That is, an oligomer can be obtained by esterifying or transesterifying a dibasic acid and a dihydric alcohol, and then synthesized by performing a polycondensation reaction under vacuum. It can also be obtained by a polyester depolymerization method as described in JP-B-53-37920. In addition, as a dibasic acid, a transesterification reaction is performed using at least one of an alkyl ester of a dicarboxylic acid such as dimethyl terephthalate, and then a polycondensation reaction is performed. A condensation reaction may be performed. However, since the melting point of bisphenol S alkylene oxide is high, for example, a dibasic acid and a dihydric alcohol are reacted at 180 to 200 ° C. under atmospheric pressure for 2 to 5 hours, and the distillation of water or alcohol is terminated. Complete the exchange reaction. Next, the pressure in the reaction system is set to a high vacuum of 1 mmHg or less, and the temperature is raised to 200 to 230 ° C. and heated at this temperature for 1 to 3 hours to obtain a crystalline polyester resin.

  Further, it is also preferable to add a pigment, a release agent, a surfactant or the like to the toner receiving layer.

  In the present invention, an inorganic pigment can be contained in the toner receiving layer for the purpose of improving the whiteness of the color electrophotographic image transfer material and making the image clear. As the inorganic pigment to be contained in the toner receiving layer, for example, powders of titanium oxide, barium sulfate, zinc oxide, talc, calcium carbonate, aluminum oxide, silicon oxide, solid solutions thereof, and the like can be used. The particle diameter of the inorganic pigment is preferably about 0.04 to 1 μm. If the particle diameter is smaller than 0.04 μm, it is difficult to uniformly disperse the inorganic pigment in the resin. If the particle diameter is larger than 1 μm, the surface of the coating film of the composition becomes too rough, resulting in image quality. It is easy to cause the fall of. Moreover, 1-30 mass% is preferable with respect to the resin composition, and, as for the addition amount of an inorganic pigment, 3-10 mass% is more preferable. If the amount added is less than 1% by mass, the effect of improving the whiteness may be poor. On the other hand, when the addition amount is more than 30% by mass, the stability of the toner receiving layer may be poor. Among these inorganic pigments, titanium oxide and barium sulfate are preferable from the viewpoint of whiteness, and a preferable average particle diameter is 0.1 to 0.8 μm.

  Further, a release agent can be added to the toner receiving layer. As the release agent, solid or waxy substances such as polyethylene wax, amide wax, fine powder of silicone resin, fine powder of fluororesin: surfactants such as fluorine and phosphate ester: paraffin, silicone Conventionally known release agents such as fluorinated oils can be used.

  Various surfactants can be added to the toner-receiving layer for the purpose of improving releasability, improving slipperiness and preventing static charge. As the surfactant, any of a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, and a cationic surfactant can be used.

  The toner receiving layer preferably contains 3 to 15% by mass of inorganic fine particles, and the inorganic fine particles are preferably titanium dioxide or silica having a particle diameter of 8 to 200 nm.

  The thickness of the toner receiving layer is preferably in the range of 5 to 20 μm. When the thickness is less than 5 μm, it is difficult to obtain a smooth and glossy image surface by fixing, and even on the fixed image surface, a step is easily left on the boundary between the high density portion and the low density portion. If it exceeds 20 μm, the problem that the receiving layer cracks when bent is likely to occur.

  When the crystalline polyester resin used for the toner receiving layer is formed into a film having a thickness of 20 μm, the luminous reflectance Y of the film is preferably 1.5% or less. When the luminous reflectance Y is large, problems such as slow solidification of the resin, unsmoothed image surface, uneven gloss, and inability to peel after fixing are likely to occur.

  The luminous reflectance Y of the toner receiving layer is measured as follows.

  First, in order to remove scattering components on the front and back surfaces, a resin film having a thickness of about 20 μm is prepared from the crystalline polyester resin used for the toner receiving layer to be measured, and this resin film is formed with a transparent cover glass for microscopic observation. Fill the gap between the glass and the film with a refractive index matching liquid (tetradecane). The sample is subjected to reflection measurement on a light and a lap with a color measuring device (for example, X-rite 968 manufactured by X-rite) satisfying a 0/45 ° geometric color measuring condition. The value of luminous reflectance Y in the CIE XYZ color system measured in this way is defined as luminous reflectance Y.

  The thickness of the resin film to be measured is preferably 20 μm, but when the scattering is 2% or less, the magnitude of the luminous reflectance Y is almost proportional to the thickness of the film, so that the thickness of the film is If it is not exactly 20 μm, the luminous reflectance Y may be calculated by converting the thickness. When the film to be measured is transparent and the cover glass is also transparent, the luminous reflectance Y is almost zero. That is, the value of the reflectance Y corresponds to the intensity of the scattering component inside the film.

  When the copolymer component such as bisphenol S or bisphenol S alkylene oxide adduct is not included or is insufficient, the scattering intensity due to crystal dispersion of the crystalline polyester resin is strong, and a large luminous reflectance Y is exhibited. The finer the crystalline dispersion of the crystalline polyester resin is, the smaller the luminous reflectance Y of this resin film becomes. Therefore, the luminous reflectance Y is an index of the crystal dispersion size.

  Here, the method for producing the resin film to be measured is not particularly limited as long as the purpose of forming a film having a uniform and uniform thickness is not impaired. For example, a smooth and good releasable base material is placed on a hot plate, etc., the resin is melted on this base material and applied with Erichsen or a bar coater, and the film is peeled off from the base material to obtain a film be able to.

Moreover, even if the film made on the base material is layered on a transparent film such as a PET film, heated and pressed, then the base material is peeled off and transferred to the transparent film, and the luminous reflectance Y is measured. If the reflectance Y ₀ of the transfer film itself is subtracted from the reflectance Y _{t of} this sample, the luminous reflectance Y for the film to be measured can be calculated.

  As a method for coating the toner receiving layer, a method of forming a uniform and smooth light scattering layer is employed. For example, there is a melt extrusion method in which inorganic fine particles and other additives are uniformly dispersed in a resin. In the melt extrusion method, a laminating method in which a molten resin film extruded through a wide slit die (so-called T-die) from a heated extruder is brought into contact with a support described later and continuously pressed with a roller, The general method etc. which extrude molten resin on a cooling roll similarly, wind up, and make into a film are mentioned. According to the melt extrusion method, a uniform film composed of the resin, inorganic fine particles, and other additives can be easily formed on the support.

  The extruder used for forming the toner-receiving layer by the melt extrusion method may be uniaxial or biaxial, but has the ability to uniformly mix white pigment and other additives in the resin. It is important to be.

  In addition, an aqueous dispersion in which a resin, inorganic fine particles, and other additives are dispersed in water can be applied by a known method such as a roll coater, a bar coater, or a spin coater.

  The color electrophotographic image transfer material of the present invention can comprise a support, a light scattering layer on the support, and the toner receiving layer on the light scattering layer.

(Support)
In the color electrophotographic image transfer material of the present invention, the support that supports the toner receiving layer and the like can withstand the fixing temperature, and has smoothness, whiteness, sliding friction, antistatic properties, post-transfer. Any material can be used as long as it satisfies the requirements in terms of dents and the like. For example, fine paper, art paper, coated paper, cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, polyolefin coated paper (especially A paper support such as a paper coated on both sides with polyethylene) or a laminate in which layers composed of any of the above-mentioned substrates are combined can also be used.

The basis weight of the support is in the range of 100 to 250 g / m ² is preferred. If the basis weight is out of this range, difficulty in touching the hand will occur. For the purpose of imparting smoothness and flatness, the support is preferably surface-treated by applying heat and pressure using an apparatus such as a machine calendar or a super calendar. In addition, when laminating the light diffusion layer on the support, pretreatment such as glow discharge treatment, corona discharge treatment, flame treatment, anchor coating, etc. is performed on the support surface in advance so that the light scattering layer and the support are in close contact with each other. From the viewpoint of improving the properties.

(Light scattering layer)
If the melt viscosity of the light diffusion layer on the surface of the transfer target in the fixing process is too high, a preferable surface structure that is uniform and high gloss over the entire image cannot be obtained. In the color electrophotographic image transfer object of the present invention, the light scattering layer is preferably formed of a polyolefin-based thermoplastic resin having a temperature Tb of 115 ° C. or higher at which the viscosity becomes 5 × 10 ³ Pa · s. . By satisfying this, it is possible to avoid the problem that bubbles due to water vapor generated from the support during fixing impair the smoothness of the surface of the light scattering layer.

  In the color electrophotographic image transfer object of the present invention, the light scattering layer preferably contains 20 to 40% by mass of a white pigment. When the amount of the white pigment is less than 20% by mass, the degree of whiteness is low, and the problem of show-through occurs when characters or the like are written on the back surface or printed. If it exceeds 40% by mass, problems such as insufficient mechanical strength of the light scattering layer and difficulty in forming a layer having a smooth surface are likely to occur. As the white pigment contained in the light scattering layer, fine particles of a known white pigment such as titanium oxide, calcium carbonate, barium sulfate can be used. From the viewpoint of increasing whiteness, it is preferable that titanium oxide is the main component.

  The thickness of the light scattering layer is preferably 20 to 50 μm. If the thickness is less than 20 μm, the whiteness is low, and show-through tends to occur when characters are written or printed on the back surface. If it exceeds 50 μm, the light scattering layer is likely to crack when bent.

  The light scattering layer is preferably formed of a thermoplastic resin, particularly a polyolefin polymer. Examples of the polyolefin polymer include low density polyethylene, high density polyethylene, polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, and ethylene-vinyl acetate copolymer. These may be used alone or in combination. In addition, other resins can be mixed with the above polymer and used as necessary within the range not impairing the object of the present invention. Of the above polymers, polypropylene is more preferred.

  Further, it is preferable to add a fluorescent whitening agent that absorbs ultraviolet rays and emits fluorescence to the light scattering layer. Such a support has a high whiteness and can provide a brightly colored image.

  As a coating method for the light scattering layer, for example, a melt extrusion method that also uniformly disperses a white pigment and other additives in a thermoplastic resin such as polypropylene can be cited. Thereby, a uniform and smooth light scattering layer can be formed. In the melt extrusion method, a laminating method in which a molten resin film extruded through a wide slit die (so-called T-die) from a heated extruder is brought into contact with the support and continuously pressed with a roller, The general method etc. which extrude molten resin on a cooling roll, wind up, and make into a film are mentioned. According to the melt extrusion method, a uniform film made of the resin, the white pigment, and other additives can be easily formed on the support. The extruder used for forming the toner receiving layer by the melt extrusion method may be uniaxial or biaxial, and has the ability to uniformly mix white pigment and other additives in the resin. It is important that

  In order to form a light scattering layer, a white pigment and other additives are uniformly dispersed in a thermoplastic resin such as polypropylene. Known methods such as a method of adding to a kneader and a method of preparing a master pellet in advance and adding it to a melt extrusion apparatus can be applied.

  Moreover, in the coating film of a light-scattering layer, it is preferable to process one side or both sides of the molten resin film extruded through the slit die (so-called T-die) by methods such as flame treatment, corona treatment, and plasma treatment. This improves the adhesion between the support and the toner receiving layer.

(Other layers)
Since the color electrophotographic image transfer material of the present invention has an effect of improving the adhesion between the toner receiving layer and the light scattering layer, it is preferable to provide a gelatin layer between the light scattering layer and the toner receiving layer. preferable. In particular, when the toner receiving layer is applied as an aqueous dispersion of constituent materials, the gelatin layer effectively acts to form a uniform color toner layer.

  The color electrophotographic image transfer material of the present invention preferably comprises a polyethylene resin layer and further an antistatic layer on the front surface and / or back surface, particularly on the back surface. Such a support has a high degree of whiteness, a smooth surface and high gloss, does not show through even when an image is formed on the back surface, is bright in color, and can provide an image having a smooth and granular feeling. In addition, it has the advantages of good transportability of the paper and less dust stains.

The antistatic layer is intended to keep the surface resistance value of the back surface in the range of about 10 ⁶ to 10 ¹⁰ Ω / cm ² , and there is no need to limit the material as long as this purpose is achieved. For example, as the antistatic layer, a coating layer such as colloidal silica or colloidal alumina, a layer obtained by mixing particles such as alumina or silica in a small amount of a binder resin, or a resin in which an ionic surfactant is dispersed is used. Examples include a coated layer.

  An intermediate layer may be provided between the toner receiving layer and the light scattering layer. The intermediate layer can provide a function as a cushion layer, a porous layer, a stiffness adjusting layer of the transfer paper, or a function as an adhesive layer in some cases. In addition, a back coat layer may be provided on the surface opposite to the surface on which the toner receiving layer is formed in order to improve running performance. In addition, when a desired surface electric resistance cannot be obtained, a conductive undercoat layer may be provided between the toner receiving layer and the light scattering layer. The conductive undercoat layer is a layer in which conductive metal oxide particles are dispersed in a binder.

Examples of the material for the conductive metal oxide particles include ZnO, TiO, SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, and MoO ₃ . These may be used alone or in combination. The particle size of the conductive metal oxide particles is preferably 0.2 μm or less.

  As the binder material for the conductive undercoat layer, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyhydroxyethyl acrylate, polyvinyl pyrrolidone, water-soluble polyester, water-soluble polyurethane, water-soluble nylon, water-soluble epoxy resin, gelatin Water-soluble polymers such as hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and derivatives thereof; water-dispersed resins such as water-dispersed acrylic resins and water-dispersed polyesters; acrylic resin emulsions, polyvinyl acetate emulsions, SBR (styrene-butadiene- Rubber) Emulsions such as emulsions; organic solvent soluble resins such as acrylic resins and polyester resins. Of these, water-soluble polymers, water-dispersed resins and emulsions are preferred. A surfactant may be further added to these polymers, and a crosslinking agent or the like may be added.

[Color electrophotographic image forming method]
The color electrophotographic image forming method of the present invention will be described in detail below.

In the color electrophotographic image forming method of the present invention, a toner image made of color toner is transferred to a transfer object, and the toner image is fixed on the transfer object by heating and pressing in a state of being superimposed on a fixing belt. The color electrophotographic image forming method according to any one of claims 1 to 14, wherein the toner image is peeled off from the fixing belt after being cooled from 30 ° C to 80 ° C. The color toner has a colorant dispersed in a binder resin, and the main component of the binder resin has a temperature Tm ′ at which the viscosity becomes 1 × 10 ⁴ Pa · s, It is characterized by being a polyester-based or styrene-acrylic thermoplastic resin having a melting point of Tm or more and less than Tm + 20 ° C.

(Color toner)
When forming a color electrophotographic image on the color electrophotographic image forming support of the present invention, the color toner has a temperature Tm ′ at which the viscosity becomes 1 × 10 ⁴ Pa · s, and the crystalline polyester resin. In order to obtain a color electrophotographic image excellent in heat resistance, low-temperature fixability, and smoothness, a polyester or styrene acrylic thermoplastic resin having a melting point of Tm or higher and lower than Tm + 20 ° C. is used as a binder resin. It is effective.

The temperature of the polyester-based or styrene-acrylic thermoplastic resin, which is the main component of the color toner, at which the viscosity becomes 1 × 10 ⁴ Pa · s (hereinafter referred to as Tm ′) is the toner of the color electrophotographic image transfer object. If the melting point of the crystalline polyester resin forming the receiving layer is higher than 20 ° C, the vicinity of the image edge at the boundary between the high-density solid image area where the development amount of the color toner image is large and the non-image area where there is no color toner image The problem of generating bubbles in the part is likely to occur. Further, when Tm ′ of the color toner is less than the melting point Tm, problems such as the color toner image being disturbed in the middle density portion and the graininess being impaired, line thickening and character collapse are likely to occur.

  The color toner used in the color electrophotographic image forming method of the present invention is an insulating particle containing a thermoplastic binder resin and a colorant, such as cyan toner, magenta toner, yellow toner, and black toner. Is mentioned.

  In order to broaden the color reproduction range, it is important to suppress irregular reflection at the interface between the colorant pigment and the binder. For example, a color toner disclosed in JP-A-4-42752 in which a pigment having a small particle diameter is highly dispersed in a binder resin is suitable.

  The binder resin can be appropriately selected according to the purpose. For example, polyester resin, polystyrene resin, polyacrylic resin, other vinyl resins, polycarbonate resin, polyamide resin, polyimide resin. And publicly known resins and copolymers thereof used for general toners such as epoxy resins and polyurea resins. Among these, a resin comprising a polyester-based or styrene-acrylic copolymer is preferable in that toner properties such as low-temperature fixability, fixing strength, and storage stability can be satisfied at the same time. The binder resin preferably has a weight average molecular weight of 5000 or more and 40,000 or less and a glass transition point of 55 ° C. or more and less than 75 ° C.

  As the colorant, a color material generally used for producing a color image can be used. Either a dye-based pigment or a pigment-based pigment can be used, but a pigment-based colorant is preferable from the viewpoint of light resistance. For example, benzidine yellow, quinoline yellow, Hansa yellow, etc. for Y (yellow), rhodamine B, rose bengal, pigment red, etc. for M (magenta), phthalocyanine blue, aniline blue, pigment blue, etc. for C (cyan), K (black) is carbon black, aniline black, a blend of color pigments, and the like.

  As for the amount of the color material in the color toner, the optimum amount differs because the spectral absorption characteristics and color development differ depending on the type. It is preferable to appropriately determine the color gamut within a general range of about 3 to 10% by mass.

  It is preferable that wax is added to the color toner. It is preferable that a wax having a melting point of 80 ° C. or higher and 110 ° C. or lower is added in a ratio of 0.2% by mass or more and less than 8% by mass. The composition of the wax can be appropriately selected according to the purpose from known materials used as the wax, and examples of the material include polyethylene resin and carnauba natural wax.

  Further, the particle diameter of the color toner is preferably 1 μm or more and 15 μm or less, and more preferably 4 μm or more and 8 μm or less from the viewpoint of obtaining an image having good granularity and gradation.

  In order to obtain an image with good graininess and tone reproducibility, it is necessary to control the fluidity and chargeability of the toner. From this viewpoint, it is preferable that inorganic fine particles and / or organic fine particles are externally added or adhered to the surface of the color toner. The average particle size of the fine particles to be externally added or adhered is preferably about 5 to 100 nm.

  The inorganic fine particles to be externally added or adhered to the surface of the color toner can be appropriately selected from known fine particles used as external additives according to the purpose. Examples of the material include silica and titanium dioxide. , Tin oxide, molybdenum oxide, and the like. In consideration of stability such as charging property, those obtained by subjecting these inorganic fine particles to a hydrophobic treatment using a silane coupling agent, a titanium coupling agent, or the like can also be used.

  The organic fine particles to be externally added or adhered to the surface of the color toner can be appropriately selected from known fine particles used as external additives according to the purpose. Examples of the material include polyester resins, Resin particles such as polystyrene resin, polyacrylic resin, vinyl resin, polycarbonate resin, polyamide resin, polyimide resin, epoxy resin, polyurea resin, and fluorine resin are preferable.

  The average particle size of the inorganic fine particles or organic fine particles to be externally added or adhered to the surface of the color toner is preferably 0.005 to 1 μm. If the average particle size is less than 0.005 μm, aggregation may occur when inorganic fine particles and / or organic fine particles are adhered to the surface of the toner, and a desired effect may not be obtained. It becomes difficult to obtain a high gloss image. 0.1 μm or less is more preferable.

  The color toner is preferably used as a developer in combination with an appropriately selected carrier known per se. In addition, as a one-component developer, a unit that is triboelectrically charged with a developing sleeve or a charging member to form a charged toner and develops it in accordance with an electrostatic latent image can be applied.

  In the color electrophotographic image forming method of the present invention, a means for forming a toner image composed of color toner (hereinafter sometimes simply referred to as a color toner image) on a color electrophotographic image transfer member is known electrophotographic. A color toner image forming apparatus of the type can be used.

(Image forming device)
A color image forming apparatus suitable for use in the color electrophotographic image forming method of the present invention is an electrostatic latent image forming an electrostatic latent image on an image carrier based on color toner image forming information output by an image processing apparatus. An image forming unit; a developing unit that develops the formed electrostatic latent image with color toner to form a color toner image; a transfer unit that transfers the color toner image onto a transfer target; and the transfer target A color electrophotographic image forming apparatus comprising: a fixing unit that fixes the color toner image on the body.

  FIG. 2 is a schematic diagram for explaining an example of a color image forming apparatus suitable for use in the color electrophotographic image forming method of the present invention. Hereinafter, the color electrophotographic image forming method of the present invention will be described in detail with reference to the drawings.

  The color image forming apparatus shown in FIG. 2 has, as an electrostatic latent image forming unit, an image processing apparatus 4 that controls an image signal for forming a color image, an exposure apparatus 6, a photosensitive drum 8, and a charging opposite to the photosensitive drum. And the like as a developing means for supplying toner to the yellow developing device 9, the magenta developing device 10, the cyan developing device 11, the rack developing device 12, and the developing devices facing the photosensitive drum 8. An intermediate transfer belt 13 having a toner containing portion (not shown) and the like as a transfer means that contacts the photosensitive drum 8 at the primary transfer position, and a transfer that faces the photosensitive drum 8 at the primary transfer position across the intermediate transfer belt 13 A fixing unit comprising a corotron 14, a secondary transfer roll pair (15, 16), a belt cleaning unit 34, and the like, and a fixing unit made of polyimide in which carbon fibers are dispersed. Fixing belt 18 Si rubber is applied to the surface of the belt 18, a pair of heating rolls (25, 26), the heat sink 27, the peeling roll 28, and a conveying device 29, and the like.

  When a color photographic image is copied using the color image forming apparatus shown in FIG. 2, the illumination 1 is first applied to the original 2 to be copied, the reflected light is color-separated by the color scanner 3, and the image processing apparatus 4 performs image processing. Thus, color image data of a plurality of colors obtained by performing color correction and image data of transparent toner are obtained. Based on the image / character signal sent from the image processing device 4, the laser diode 5 is used to make a laser beam modulated for each color, and the laser beam is irradiated from the photosensitive unit 6 onto the surface of the photosensitive drum 8. Then, a potential difference occurs between the exposed portion and the non-exposed portion on the surface of the photosensitive drum 8, and an electrostatic latent image is formed by the potential difference. A plurality of electrostatic latent images are formed by irradiating the photosensitive drum 8 made of an organic photoreceptor a plurality of times for each color with this laser beam. The plurality of electrostatic latent images are used with four color toners of yellow, magenta, cyan, and black, and these are sequentially processed in a yellow developing unit 9, a magenta developing unit 10, a cyan developing unit 11, and a black developing unit 12. Develop.

  That is, when the electrostatic latent image on the surface of the photosensitive drum 8 faces the rotary developing unit (9, 10, 11, 12), first, the magnetic brush held on the developing roll of the yellow developing device 9 is the electrostatic latent image. The yellow toner is selectively adhered to the electrostatic latent image portion. In this way, a visible image of yellow toner, that is, a toner image T (Y) is formed on the surface of the photosensitive drum 8. Then, when the toner image T (Y) reaches a position facing the transfer corotron 14 as the photosensitive drum 8 rotates, the toner image T (Y) is electrostatically transferred onto the intermediate transfer belt 13 by the primary transfer electric field formed by the transfer corotron 14. The

  The toner image T (Y) primarily transferred onto the intermediate transfer belt 13 moves along with the rotation of the intermediate transfer belt 13 that is rotationally driven in the direction of the arrow in the drawing, and reaches the position facing the transfer corotron 14 again. At this time, the secondary transfer roll 16 and the belt cleaning unit 34 are separated from the intermediate transfer belt 13.

  Next, a visible image with magenta toner, that is, a toner image T (M) is formed on the photosensitive drum 8 by the same operation. The toner image T (M) on the photosensitive drum 8 is also confronted with the transfer corotron 14 at the timing when the toner image T (Y) already primary-transferred on the intermediate transfer belt 13 reaches the position facing the transfer corotron 14 again. The toner image T (M) is superimposed on the toner image T (Y) on the intermediate transfer belt 13 by the primary transfer electric field formed by the transfer corotron 14. Similarly, a toner image T (C) made of cyan toner and a toner image T (Bk) made of black toner are superimposed one after another, and a full color toner image T (F) is finally formed on the surface of the intermediate transfer belt 13. At this time, the secondary transfer roll 16 and the belt cleaning unit 34 are separated from the intermediate transfer belt 13.

  Thereafter, the color electrophotographic image transfer object 17 is synchronized with the timing at which the toner image T (F) on the intermediate transfer belt 13 faces the secondary transfer roll pair (15, 16). (15, 16) is conveyed to the pressure contact portion.

  Then, the toner image T (F) on the intermediate transfer belt 13 is secondarily transferred onto the color electrophotographic image transfer material 17 by the secondary transfer rolls (25, 26). At this time, the toner image T (F) is transferred to the toner receiving layer of the color electrophotographic image transfer material 17. Here, the slight toner remaining on the surface of the intermediate transfer belt 13 without being subjected to the secondary transfer is removed by the belt cleaning unit 34.

  The color electrophotographic image transfer material 17 onto which the toner image T (F) has been transferred in this way is conveyed to the nip portion of the heating roll pair (25, 26) by the conveying device 29. Each heating roll (25, 26) is preheated to the melting temperature of the toner receiving layer. Further, a force of about 980 N is applied to the nip portion of the heating roll pair (25, 26). Further, the heating roll pair (25, 26) is driven to rotate, and the fixing belt 18 is also driven following this. The fixing belt 18 is in contact with the surface of the color electrophotographic image transfer body 17 to which the color toner image is transferred at the nip portion of the heating roll pair (25, 26), and the toner image and the toner receiving layer are heated and melted. A color toner image is embedded in the toner receiving layer. The color electrophotographic image transfer body 17 and the fixing belt 18 are conveyed to the peeling roll 28 in a bonded state. During this time, the fixing belt 18, the color toner image and the color electrophotographic image transfer body 17 are transferred to the heat sink 27. Cooled by. Then, due to the curvature of the peeling roll 28, the color toner image and the color electrophotographic image transfer material 17 are peeled together from the fixing belt 18. As described above, a high-gloss and smooth color image is formed on the color electrophotographic image transfer material 17.

  Here, the photosensitive drum 8 is used as the photosensitive member, but there is no particular limitation, and a known one may be used, which may be a single layer structure, a multilayer structure and a function separation type. Also good. The material may be an inorganic photoreceptor such as selenium or amorphous silicon, or an organic photoreceptor using a phthalocyanine pigment, a bisazo pigment or the like as a charge generation layer.

  As the charging device, a charger 7 is used. For example, contact charging using a conductive or semiconductive roller, brush, film, rubber blade, etc., corotron charging using corona discharge, scorotron charging, etc. Means known per se can be used.

  The exposure device 6 can use known exposure means such as a semiconductor laser and a scanning device, a laser ROS comprising an optical system, and an LED head. In order to produce a uniform and high-resolution exposure image, it is preferable to use a laser ROS or LED head.

  As the image processing apparatus 4, known means can be used as long as a signal can be formed so as to develop the toner image at a desired position on the support.

  As the developing means, a known developing device can be used regardless of the one-component or two-component system as long as the purpose of forming a uniform and high-resolution toner image on the photosensitive member is achieved. From the viewpoint of good graininess and smooth tone reproduction, a two-component developing device is preferable.

  For the transfer means, for example, an electrically charged or semiconductive roller, brush, film, rubber blade or the like to which a voltage is applied is used to create an electric field between the photosensitive member and the support or intermediate transfer member, thereby charging the toner. Means for transferring a toner image made of particles, means for transferring a toner image made of charged toner particles by corona charging the back surface of a support or an intermediate transfer body with a corotron charger or a scorotron charger using corona discharge Any known means can be used.

  As the intermediate transfer member, an insulating or semiconductive belt-shaped transfer member or a drum-shaped transfer member having an insulating or semiconductive surface can be used. A semiconductive belt material is preferable from the viewpoint of stably maintaining transferability during continuous image production and reducing the size of the apparatus. As such a belt material, a belt material made of a resin material in which a conductive filler such as carbon fiber is dispersed is known. As this resin, for example, a polyimide resin is preferable.

  The secondary transfer means uses, for example, a conductive or semiconductive roller, brush, film, rubber blade, etc., to which a voltage is applied, and creates an electric field between the intermediate transfer member and the support to charge toner particles. A means for transferring a toner image comprising, a means for corona charging a back surface of an intermediate transfer member with a corotron charger or a scorotron charger utilizing corona discharge, and a means for transferring a toner image composed of charged toner particles. Means can be used.

  As the fixing means, (1) the color toner image is transferred by passing between the pair of rolls that have a heating source such as an incandescent lamp inside and that are oppositely pressed against each other. (2) A fixing belt having a release layer such as silicone rubber is superimposed on the surface of the transfer material to which the color toner image has been transferred, and in this state, an incandescent lamp or the like The color toner layer is transferred to a transfer object by separating and peeling the belt and the color toner layer after passing through a pair of heating rolls that are in pressure contact with each other and having the heat source to cool, and cooling the toner layer. For example, a cooling peeling fixing device that adheres to the substrate can be used.

  The latter fixing method is preferred particularly when an image having excellent full color reproducibility is to be produced. Further, by combining the latter fixing method and the color electrophotographic image transfer material of the present invention, uniform high gloss can be obtained regardless of the image density.

  A known conveying device can be used as a conveying device that conveys a transfer medium on which a color image is formed to a fixing device. Since it is preferable that the conveyance speed be constant, for example, a device that is driven by sandwiching the transfer target body between a pair of rubber rolls that rotate at a constant rotational speed, or a pair of devices that are driven at a constant speed by a motor or the like It is possible to use a device in which a belt made of rubber or the like is wound around a roll, and the object to be transferred is placed on the belt and driven at a constant speed. When an unfixed color toner image is formed, the latter device is preferable from the viewpoint of not disturbing the toner image.

  As the base material of the fixing belt, a resin film such as polyimide or a metal film such as stainless steel can be used. Since it is required that the heat resistant temperature is high and the separability is good, it is preferable to laminate a separable layer on a heat resistant base substrate. As the base material, it is preferable to use a resin film such as polyimide resin or polyethylene terephthalate resin, or a metal belt such as a stainless steel belt. Further, it is preferable to use silicone rubber, fluororubber, fluororesin or the like for the separating layer.

  In order to maintain stable peelability of the fixing belt and reduce dirt due to dust, the resistance value must be adjusted by dispersing conductive additives such as conductive carbon particles and conductive polymer. Is preferred.

  The fixing belt may have a sheet shape, but it is also preferable to use an endless belt shape. Further, from the viewpoint of smoothness, the glossiness of the surface as measured with a 75 ° gloss meter is preferably 60 or more.

  A known device can be used as a heating / pressurizing device for heating and pressing the fixing belt and the transfer material on which the color toner image is formed. For example, there is an apparatus that drives a fixing belt and a transfer target on which a color image is formed between a pair of rolls driven at a constant speed. Here, one or both of the rolls are heated to a temperature at which the toner and the toner receiving layer of the transfer target melt, for example, by providing a heat source at the center, and the two rolls are pressed against each other. ing. Preferably, one or both roll surfaces are provided with a silicone rubber or fluororubber layer, and the length of the region to be pressurized and heated is preferably in the range of about 1 to 8 mm.

The roll surface temperature in fixing is preferably adjusted so that the viscosity of the toner receiving layer at the rear end of the region where the two rolls are in pressure contact is 1 × 10 ² to 1 × 10 ³ Pa · s.

  As a peeling device, a means for inserting a peeling claw between a belt and a transfer object, or a means for peeling by providing a roll with a small curvature at a peeling position is known. There is no particular limitation as long as the transfer target on which the toner image is formed from the fixing belt is stably peeled off.

  From the viewpoint of the size of the apparatus, it is preferable to provide a cooling device such as a heat sink or a heat pipe between the heating / pressurizing device and the peeling device to increase the cooling rate.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples.

(Synthesis of crystalline polyester)
Synthesis of crystalline polyester A In a heat-dried three-necked flask, 194 parts by weight of dimethyl terephthalate, 152 parts by weight of 1,9-nonanediol, 3.10 parts by weight of ethylene glycol, and bisphenol S ethylene oxide adduct After putting 16.92 parts by weight and 0.15 part by weight of dibutyltin oxide as a catalyst, the air in the container is brought into an inert atmosphere with nitrogen gas by depressurization, and stirred at 180 ° C. for 5 hours by mechanical stirring. Went.

  Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When the effluent disappeared and became viscous, it was air-cooled to stop the reaction. The obtained resin was designated as crystalline polyester resin A.

  As a result of molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained crystalline polyester resin A had a weight average molecular weight (Mw) of 33,000 and a number average molecular weight (Mn) of 14,000.

  Moreover, when melting | fusing point Tm of crystalline polyester A was measured by the above-mentioned measuring method using the differential scanning calorimeter (DSC), it had a clear peak and the temperature of the peak top was 85 degreeC.

Synthesis of crystalline polyester B In a heat-dried three-necked flask, 194 parts by weight of dimethyl terephthalate, 152 parts by weight of 1,9-nonanediol, 16.92 parts by weight of bisphenol S ethylene oxide adduct, After adding 0.15 part by weight of dibutyltin oxide, the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and stirred at 200 ° C. for 5 hours by mechanical stirring.

Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as crystalline polyester resin B.
As a result of molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the resulting crystalline polyester resin B had a weight average molecular weight (Mw) of 13200 and a number average molecular weight (Mn) of 6000.

  Moreover, when melting | fusing point Tm of crystalline polyester B was measured using the differential scanning calorimeter (DSC) with the above-mentioned measuring method, it had a clear peak and the temperature of the peak top was 80 degreeC.

Synthesis of polyester C In a heat-dried three-necked flask, 194 parts by weight of dimethyl terephthalate, 120 parts by weight of 1,9-nonanediol, 15.5 parts by weight of ethylene glycol, and 84. After 6 parts by weight and 0.15 part by weight of dibutyltin oxide as a catalyst were added, the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and the mixture was stirred at 180 ° C. for 5 hours with mechanical stirring. It was. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When the effluent disappeared and became viscous, it was air-cooled to stop the reaction. The obtained resin was designated as crystalline polyester resin C.

  In the molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained crystalline polyester resin C had a weight average molecular weight (Mw) of 24,000 and a number average molecular weight (Mn) of 11,000.

  Moreover, when melting | fusing point Tm of polyester C was measured using the above-mentioned measuring method using a differential scanning calorimeter (DSC), it did not have a clear peak but the step-like endothermic change was confirmed. The glass transition point Tg at the midpoint of the stepwise endothermic change was 55 ° C.

Synthesis of crystalline polyester D In a heat-dried three-necked flask, 194 parts by weight of dimethyl terephthalate, 152 parts by weight of 1,9-nonanediol, 15.81 parts by weight of bisphenol A ethylene oxide adduct, After adding 0.15 part by weight of dibutyltin oxide, the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, and the mixture was stirred at 180 ° C. for 5 hours by mechanical stirring.

Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as crystalline polyester resin D.
As a result of molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained crystalline polyester resin D had a weight average molecular weight (Mw) of 22,400 and a number average molecular weight (Mn) of 10,900.

  Moreover, when melting | fusing point Tm of crystalline polyester D was measured using the differential scanning calorimeter (DSC) with the above-mentioned measuring method, it had a clear peak and the temperature of the peak top was 90 degreeC.

Synthesis of polyester E In a heat-dried three-necked flask, 194 parts by weight of dimethyl terephthalate, 120 parts by weight of 1,9-nonanediol, 79.1 parts by weight of bisphenol A ethylene oxide adduct, and dibutyltin as a catalyst After adding 0.15 part by weight of oxide, the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and stirred at 180 ° C. for 5 hours by mechanical stirring.

  Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as crystalline polyester resin E.

  The molecular weight measurement (polystyrene conversion) by gel permeation chromatography showed that the obtained crystalline polyester resin E had a weight average molecular weight (Mw) of 17100 and a number average molecular weight (Mn) of 7675.

  Moreover, when melting | fusing point Tm of the polyester E was measured using the differential scanning calorimeter (DSC) with the above-mentioned measuring method, it did not have a clear peak but the step-like endothermic change was confirmed. The glass transition point Tg at the midpoint of the stepwise endothermic change amount was 42 ° C.

Synthesis of crystalline polyester F After placing 194 parts by weight of dimethyl terephthalate, 160 parts by weight of 1,9-nonanediol, and 0.15 parts by weight of dibutyltin oxide as a catalyst in a heat-dried three-necked flask, The air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and stirring was performed at 180 ° C. for 5 hours by mechanical stirring.

Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 2 hours, and air-cooled when it became a viscous state, and reaction was stopped. The obtained resin was designated as crystalline polyester resin F.
In the molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained crystalline polyester resin F had a weight average molecular weight (Mw) of 24,000 and a number average molecular weight (Mn) of 10,900.

  Moreover, when melting | fusing point Tm of crystalline polyester F was measured with the above-mentioned measuring method using the differential scanning calorimeter (DSC), it had a clear peak and the temperature of the peak top was 94 degreeC.

Synthesis of crystalline polyester G In a heat-dried three-necked flask, 202 parts by weight of sebacic acid, 62.07 parts by weight of ethylene glycol, 16.92 parts by weight of bisphenol S ethylene oxide adduct, and dibutyltin oxide as a catalyst After adding 0.15 weight part, the air in a container was made into inert atmosphere with nitrogen gas by pressure reduction operation, and it stirred at 180 degreeC by mechanical stirring for 5 hours.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When the effluent disappeared and became viscous, it was air-cooled to stop the reaction. The obtained resin was designated as crystalline polyester resin G.

  The molecular weight measurement (polystyrene conversion) by gel permeation chromatography revealed that the obtained crystalline polyester resin G had a weight average molecular weight (Mw) of 12000 and a number average molecular weight (Mn) of 5600.

  Moreover, when melting | fusing point Tm of crystalline polyester G was measured using the differential scanning calorimeter (DSC) with the above-mentioned measuring method, it had a clear peak and the temperature of the peak top was 60 degreeC.

ＴＰＡ：テレフタル酸(ジメチル) ＮＤ：1,9-ノナンジオール SebAc：セバシン酸
ＥＧ：エチレングリコール BPS-EO：ビスフェノールＳエチレンオキサイド
BPＡ-EO：ビスフェノールＡエチレンオキサイド

TPA: terephthalic acid (dimethyl) ND: 1,9-nonanediol SebAc: sebacic acid EG: ethylene glycol BPS-EO: bisphenol S ethylene oxide
BPA-EO: Bisphenol A ethylene oxide

  Here, the used toner material was evaluated as follows. That is, gel permeation chromatography was used for measuring the molecular weight. Tetrahydrofuran was used as the solvent. The average particle diameter of the toner was measured using a Coulter counter, and a weight average d50 was applied. The viscosity of the resin was measured using a rotating plate rheometer (Rheometers RDAII) at an angular velocity of 1 rad / s.

(Example 1)
− Color electrophotographic image transfer material −
As Example 1, as shown in FIG. 1, the color of the present invention having a structure of toner receiving layer 101 / light scattering layer 102 / support (base paper 103) / back surface layer (back surface resin 104 / antistatic layer 105). An electrophotographic image transfer member was prepared as follows.

(Support)
As the support, a flame-treated base paper made of pulp raw material and having a thickness of 150 μm was used.

(Light scattering layer)
Titanium dioxide (KA-10 manufactured by Titanium Industry Co., Ltd., particle size 300 to 500 nm) was mixed at a ratio of 25 parts by weight with 100 parts by weight of polyethylene resin, and this was mixed into a melt extruder heated to 200 ° C. The light diffusion layer having a thickness of 30 μm was laminated on the surface of the support by charging, discharging from the T die to the surface of the support, and niping and laminating between the nip roll and the cooling roll. Furthermore, both surfaces of this laminate after passing through the T die were subjected to corona discharge treatment using a corona treatment device. In this light scattering layer, Tb is 130 ° C.

(Toner-receiving layer)
The pellets of crystalline polyester A are put into a melt extruder heated to 170 ° C., ejected from the T die to the laminate, and niped and laminated between a nip roll and a cooling roll to laminate the laminate. A toner receiving layer having a thickness of 20 μm was further laminated on the light scattering layer of the body. In this toner receiving layer, Tm is 85 ° C.

(Back layer)
In addition, the polyethylene resin is put into a melt extruder heated to 200 ° C., discharged from a T-die on the back of the support, and niped and laminated between a nip roll and a cooling roll to obtain a thickness of 30 μm. A polyethylene layer was prepared, and an antistatic layer was laminated thereon by further applying colloidal silica as an antistatic agent with a bar coater. Here, both surfaces of the color electrophotographic image transfer object after passing through the T die are subjected to corona discharge treatment by a corona treatment device.

− Color toner developer −
As a binder resin, linear polyester obtained from terephthalic acid / bisphenol A ethylene oxide adduct / cyclohexanedimethanol (molar ratio = 5: 4: 1, Tg = 62 ° C., Mn = 4500, Mw = 10000) was used. For 100 parts by weight, in the case of yellow toner, 5 parts by weight of benzidine yellow as a colorant, in the case of magenta toner, 4 parts by weight of pigment red as a colorant, and in the case of cyan toner, 4 parts by weight of phthalocyanine blue as a colorant In the case of black toner, 5 parts by weight of carbon black as a colorant are mixed, heated and melted and mixed using a Banbury mixer, pulverized with a jet mill, and then classified with a wind classifier, d50 = 7 μm fine particles were prepared.

The following two types of inorganic fine particles A and B were adhered to 100 parts by weight of the fine particles with a high speed mixer to obtain a color toner. The inorganic fine particles A are SiO ₂ (the surface is hydrophobized with a silane coupling agent, the average particle size is 0.05 μm, and the addition amount is 1.0 part by weight). The inorganic fine particles B are TiO ₂ (the surface is hydrophobized with a silane coupling agent, the average particle diameter is 0.02 μm, the refractive index is 2.5, and the addition amount is 1.0 part by weight). The Tm ′ of each color toner was 105 ° C.

  A two-component color toner developer was prepared by mixing 100 parts by weight of the same carrier as the black developer for a color copier (Fuji Xerox Co., Ltd. Acolor635) and 8 parts by weight of this color toner.

− Color image production device −
The color image forming apparatus of FIG. 2 described above was used as the color image production apparatus. The speed of the image forming process excluding the fixing process is 160 mm / s. The weight ratio of the toner and the carrier, the photosensitive member charging potential, the exposure amount, and the development bias were adjusted so that the development amount of the color toner in the solid image portion was 0.7 (mg / cm ² ) for each color.

(Fixing belt)
As the base material of the fixing belt 18, a polyimide film in which conductive carbon having a thickness of 80 μm was dispersed and 50 μm of KE4895 silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied. The heating rolls (25, 26) are made of a core material made of aluminum provided with a 2 mm thick silicone rubber layer, and a halogen lamp is arranged as a heat source in the center thereof. Both roll surface temperatures were varied between 100 ° C and 170 ° C. The fixing speed was 30 mm / s. The temperature of the transfer object at the peeling position is 70 ° C.

  A portrait color electrophotographic image was output using the above color image production apparatus.

(Example 2)
A color electrophotographic image was formed on the transfer material in the same manner as in Example 1 except that the toner receiving layer was changed as follows. That is, pellets of crystalline polyester B are put into a melt extruder heated to 170 ° C., discharged from a T die, and between the nip roll and the cooling roll with respect to the light diffusion layer formed on the support. And a toner receiving layer having a thickness of 20 μm was laminated. In this toner receiving layer, Tm was 80 ° C.

(Example 3)
A color electrophotographic image was formed on the transfer medium in the same manner as in Example 1 except that the color toner was changed as follows. That is, a color toner for DCC500 (Fuji Xerox Co., Ltd.) was used. The color toner had a Tm ′ of 105 ° C.

Example 4
A color electrophotographic image was formed on the transfer material in the same manner as in Example 1 except that the toner receiving layer and the color toner were changed as follows. That is, the pellets of crystalline polyester B are put into a melt extruder heated to 170 ° C., discharged from a T die, and a nip between a nip roll and a cooling roll on a support on which a light diffusion layer is formed. Then, a toner receiving layer having a thickness of 20 μm was laminated. In this toner receiving layer, Tm is 80 ° C. In addition, a color toner for DCC500 (Fuji Xerox Co., Ltd.) was used. The color toner had a Tm ′ of 105 ° C.

(Comparative Example 1)
A color electrophotographic image was formed on the transfer material in the same manner as in Example 1 except that the toner receiving layer was changed as follows. That is, polyester C pellets are put into a melt extruder heated to 170 ° C., discharged from a T-die, and nip is laminated between a nip roll and a cooling roll on a support on which a light diffusion layer is formed. As a result, a toner receiving layer having a thickness of 20 μm was laminated. No clear Tm was observed in the toner receiving layer, and the glass transition temperature Tg was 55 ° C.

(Comparative Example 2)
A color electrophotographic image was formed on the transfer material in the same manner as in Example 1 except that the toner receiving layer was changed as follows. That is, the pellets of crystalline polyester D are put into a melt extruder heated to 170 ° C., discharged from a T die, and a nip between a nip roll and a cooling roll on a support on which a light diffusion layer is formed. Then, a toner receiving layer having a thickness of 20 μm was laminated. In this toner receiving layer, Tm was 90 ° C.

(Comparative Example 3)
A color electrophotographic image was formed on the transfer material in the same manner as in Example 1 except that the toner receiving layer was changed as follows. That is, polyester E pellets are put into a melt extruder heated to 170 ° C., ejected from a T-die, and nipped between a nip roll and a cooling roll on a support on which a light diffusion layer is formed. As a result, a toner receiving layer having a thickness of 20 μm was laminated. No clear Tm was observed in the toner receiving layer, and the glass transition temperature Tg was 42 ° C.

(Comparative Example 4)
A color electrophotographic image was formed on the transfer material in the same manner as in Example 1 except that the toner receiving layer was changed as follows. That is, the pellets of crystalline polyester F are put into a melt extruder heated to 170 ° C., discharged from a T die, and a nip between a nip roll and a cooling roll on a support on which a light diffusion layer is formed. Then, a toner receiving layer having a thickness of 20 μm was laminated. The toner receiving layer had a Tm of 94 ° C.

(Comparative Example 5)
A color electrophotographic image was formed on the transfer material in the same manner as in Example 1 except that the toner receiving layer was changed as follows. That is, pellets of crystalline polyester G are put into a melt extruder heated to 170 ° C., discharged from a T die, and a nip between a nip roll and a cooling roll on a support on which a light diffusion layer is formed. Then, a toner receiving layer having a thickness of 20 μm was laminated. In this toner receiving layer, Tm was 60 ° C.

(Comparative Example 6)
A color electrophotographic image was formed on the transferred material in the same manner as in Example 1 except that the transferred material was changed to mirror-coated gold paper (210 g / m ² , manufactured by Oji Paper Co., Ltd.).

(Comparative Example 7)
A color electrophotographic image was formed on the transferred material in the same manner as in Example 1 except that the transferred material was changed to J paper (Fuji Xerox Co., Ltd.).

(Comparative Example 8)
A color electrophotographic image was formed on the transferred material in the same manner as in Example 1 except that the toner receiving layer was not provided on the transferred material. Table 2 shows a list of produced color images.

  The following evaluation was performed when producing the above-mentioned transferred body for color electrophotographic image or for the manufactured transferred body for color electrophotographic image.

(Luminous reflectance)
The luminous reflectance Y of the toner receiving layer was measured according to the following procedure.

  The thermoplastic resin for forming the toner receiving layer obtained in Examples and Comparative Examples was coated on a color OHP sheet manufactured by Fuji Xerox Co., Ltd. at the same thickness as each example to form a transparent image.

  A cover glass for microscopic observation was placed on the front and back surfaces of the transparent image, and the gap between the image and the cover glass was filled with tetradecane.

  This was measured on a light trap with a color measuring device (X-rite 968 manufactured by X-rite) to measure the reflectance Y '.

A cover glass for microscopic observation was placed on the front and back surfaces of the OHP film not coated with the thermoplastic resin, the gap between the image and the cover glass was filled with tetradecane, and the reflectance Y ₀ was measured by the same procedure.

The luminous reflectance Y was calculated as Y′−Y ₀ .

(Image evaluation)
-Mechanical strength-
The to-be-transferred bodies obtained in Examples and Comparative Examples were wound around metal rolls having different radii, and the minimum radius that did not cause cracks was examined. This radius is
-Less than 10mm: ○
・ For 10 mm or more and less than 30 mm: △
・ For 30mm or more: ×
It was.

-Heat resistance-
The surface of the transferred body obtained in Examples and Comparative Examples was brought into contact with each other and placed in a constant temperature layer maintained at 45 ° C. with a pressure of 2940 Pa applied, and after about 3 days, about 22 ° C. It returned to room temperature and peeled.
・ Peeled off without surface damage and uncomfortable: ○
・ There was no surface destruction, but there was a feeling of adhesion and peeling noise when peeling: △
・ Surface is destroyed: ×
It was.

-Low temperature fixability-
As an evaluation of the low-temperature fixability, the glossiness of the white paper portion of the images obtained in Examples and Comparative Examples was measured with a 75 ° gloss meter (Murakami Color Research Laboratory Co., Ltd.). The fixing temperature when the glossiness is 90 or more
・ When the temperature is below 110 ℃: ○
・ If the temperature is 110 ° C or higher and lower than 130 ° C: △
・ When the temperature is 130 ℃ or higher: ×
It was.

-Smoothness-
The image smoothness obtained in Examples and Comparative Examples was confirmed visually. The temperature range where bubbles could not be recognized on the image surface
・ In case of 30 ℃ or higher: ○
・ When the temperature is between 10 ℃ and less than 30 ℃: △
・ When the temperature is 10 ℃ or higher: ×
It was.

-Solidification speed-
The speed of solidification was evaluated as follows.
-If the image output from the fixing device is completely solid and you cannot touch it with your hand:
If the image output from the fixing device is not completely solidified, but can be output without defects on the image surface, and there is no problem with the smoothness of the image surface even if the next output image overlaps: Δ
When the image output from the fixing device is not solidified, the image surface is not smooth, gloss unevenness, or the image sticks to the belt even after passing the peeling roll, and cannot be peeled: ×

-Overall picture quality-
In the examples and comparative examples, the overall preference of images obtained at a fixing temperature of 140 ° C. was evaluated by classifying into the following five categories.
・ Very favorable: 5 points ・ Preferable: 4 points ・ Normal: 3 points ・ Unfavorable: 2 points ・ Very unfavorable: 1 point The number of subjects is 10 and the average score of 10 people is
・ In the case of 3.5 points or more: ○
・ If the temperature is 2.5 ℃ or more and less than 3.5: △
・ If less than 2.5 points: ×
It was.

  Table 3 shows a list of evaluation results.

  The images of Examples 1 to 3 were all good in mechanical strength, heat resistance, low-temperature fixability, smoothness, and solidification rate, and had high overall image quality. In particular, in Example 1, a particularly good image was obtained. In Example 4, although heat resistance, smoothness, and overall image quality were slightly inferior, they were at a level causing no practical problem.

  The image of Comparative Example 1 could not be peeled off by the peeling roll. After passing through the peeling roll, when peeled off from the belt by hand, the image surface was not smooth and gloss unevenness occurred. In addition, when a heat resistance test was performed, the image surface that was faced by applying a load for 3 days in a 45 ° C. constant temperature bath adhered and could not be peeled off.

  The image of Comparative Example 2 could not be peeled off by the peeling roll. After passing through the peeling roll, when peeled off from the belt by hand, the image surface was not smooth and gloss unevenness occurred. In addition, the overall gloss was low and the overall image quality was poor.

  The image of Comparative Example 3 could not be peeled off by the peeling roll. After passing through the peeling roll, when peeled off from the belt by hand, the image surface was not smooth and gloss unevenness occurred. In addition, when a heat resistance test was performed, the image surface that was faced by applying a load for 3 days in a 45 ° C. constant temperature bath adhered and could not be peeled off.

  Although the image of Comparative Example 4 could be peeled off by the peeling roll, when the next image was output and overlapped, the surface layer was not completely solidified, resulting in uneven gloss on the image surface. Also, overall gloss was low and overall image quality was poor.

  The image of Comparative Example 5 was poor in both heat resistance and mechanical strength. The image of Comparative Example 6 had poor color reproduction and poor granularity. The image of Comparative Example 7 had low gloss and poor color tone and graininess. The image of Comparative Example 8 had high gloss at the low density part and high density part, but the smoothness was poor at the middle density part and the gloss was low.

FIG. 1 is a schematic explanatory view showing an example of a color electrophotographic image transfer member of the present invention. FIG. 2 is a schematic explanatory view showing an example of a color image forming apparatus used in the color electrophotographic image forming method of the present invention.

Explanation of symbols

1: illumination, 2: document, 3: color scanner, 4: image processing device, 5: laser diode, 6: exposure device, 7: charger, 8: photosensitive drum, 9: yellow developer, 10: magenta developer 11: Cyan developing device, 12: Black developing device, 13: Intermediate transfer belt, 14: Transfer corotron, 15: Secondary transfer roll, 16: Secondary transfer roll, 17: Transfer object for color electrophotographic image, 18 : Fixing belt, 25: heating roll, 26: heating roll, 27: heat sink, 28: peeling roll, 29: conveying device, 34: belt cleaning unit,
101: Toner receiving layer, 102: Light diffusion layer, 103: Support, 104: Back surface resin layer, 105: Antistatic layer

Claims (15)

A color electrophotographic image transfer material provided with a toner receiving layer formed of a crystalline polyester resin,
The crystalline polyester-based resin contains an aromatic dicarboxylic acid component as an acid-derived constituent component in an amount of 90 mol% or more based on the total acid-derived constituent component, and a linear aliphatic diol as an alcohol-derived constituent component. In contrast, 90 mol% or more and 99 mol% or less is included, and bisphenol S or bisphenol S alkylene oxide adduct is included in the range of 2 mol% or more and 15 mol% or less with respect to all alcohol-derived components. A color electrophotographic image transfer material characterized by the above.   The color electrophotographic image transfer object according to claim 1, wherein the crystalline polyester resin has a melting point Tm of 80 ° C. or more and 110 ° C. or less.   The color electrophotographic image transfer object according to claim 1, wherein the linear aliphatic diol is a linear aliphatic diol having 6 to 12 carbon atoms.   The acid-derived constituent component of the crystalline polyester resin is mainly composed of an aromatic dicarboxylic acid derived from terephthalic acid, 2,6-naphthalenedicarboxylic acid, or 4,4′-biphenyldicarboxylic acid, The color electrophotographic image transfer object according to claim 1.   The color electrophotographic image transfer object according to any one of claims 1 to 4, wherein the crystalline polyester resin has a weight average molecular weight of 15000 to 50000.   The color electrophotography according to any one of claims 1 to 5, wherein when the crystalline polyester resin is formed into a film having a thickness of 20 µm, the luminous reflectance Y of the film is 1.5% or less. Image transfer object.   The color electrophotographic image transfer object according to claim 1, wherein the toner-receiving layer contains 3 to 15% by mass of inorganic fine particles.   8. The color electrophotographic image transfer object according to claim 7, wherein the inorganic fine particles are titanium dioxide or silica having a particle diameter of 8 to 200 nm.   The color electrophotographic image transfer object according to claim 1, comprising a support, a light scattering layer on the support, and the toner receiving layer on the light scattering layer. 10. The color electrophotography according to claim 9, wherein the light scattering layer is formed of a polyolefin-based thermoplastic resin having a temperature Tb of 115 ° C. or more at which the viscosity becomes 5 × 10 ³ Pa · s. Image transfer object.   The color electrophotographic image transfer object according to claim 9 or 10, wherein the light scattering layer contains 20 to 40% by mass of a white pigment. The basis weight of the support is 100 to 250 g / m ² , the thickness of the light scattering layer is 20 to 50 μm, and the thickness of the toner receiving layer is 5 to 20 μm. Item 12. A color electrophotographic image transfer object according to any one of Items 9 to 11.   The color electrophotographic image transfer object according to claim 9, further comprising a gelatin layer between the light scattering layer and the toner receiving layer.   The color electrophotographic image transfer object according to claim 1, further comprising an antistatic layer on a front surface and / or a back surface thereof. A toner image made of color toner is transferred to a transfer material, and the toner image is fixed on the transfer material by being heated and pressed in a state of being superimposed on a fixing belt, and after cooling from 30 ° C. to 80 ° C., A color electrophotographic image forming method for peeling off the toner image from a fixing belt,
The transferred object is a transferred object for a color electrophotographic image according to any one of claims 1 to 14.
In the color toner, a colorant is dispersed in a binder resin. The main component of the binder resin is a temperature Tm ′ at which the viscosity becomes 1 × 10 ⁴ Pa · s, and a melting point Tm of the crystalline polyester resin. A method for forming a color electrophotographic image, which is a polyester-based or styrene-acrylic thermoplastic resin having a Tm + 20 ° C. or lower.

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