JP3189098B2 - Color image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming method for forming a high-quality full-color image by an electrophotographic method applied to a color copying machine or a color printer.

[0002]

2. Description of the Related Art In an example of a method for forming a full-color image by electrophotography, for example, B (blue), G (blue), and G (color) are formed on a photoreceptor using an organic or inorganic photoconductive material.
(Green), R (red) and ND if necessary
(Neutral) or other color separation light is emitted to form an electrostatic latent image for each color, and these electrostatic latent images for each color are Y (yellow), M (magenta), C
(Cyan) and, if necessary, color toners such as BK (black) to form color toner images for each color.

The color toner images of the respective colors are superimposed on a photoreceptor and then collectively transferred to a transfer member, or are transferred onto a transfer member every time a toner image is formed on the photoreceptor. On the transfer body.

The color toner image superimposed on the transfer body is heated and fixed by a heat roller fixing device to form a color image.

A color toner used in such an electrophotographic method is composed of particles formed by dispersing a dye or a pigment or the like in a thermoplastic resin, and has an average particle size of usually 5%.
2020 μm. For this reason, as described in JP-A-63-92965, the color toner image is formed of one to four toner particle layers, and the color toner image after fixing is also perpendicular to the surface. It will have irregularities.

A color image having irregularities by such an electrophotographic method has poor color reproducibility and glossiness as compared with ordinary photographs and printing, and as a result, is inferior in color image quality.

In order to improve the image quality of such a color image, for example, in (A) JP-A-63-92965, a transparent resin layer is formed on a transfer substrate, and There has been proposed a technique of embedding toner particles in a heating roller.

(B) Japanese Patent Application Laid-Open No. 3-38659 discloses an image forming method for forming a toner image on a transparent coat layer provided on an image support. The temperature difference at which the viscosity becomes 10 ⁵ poise is 3 <T ₁ −
T ₂ <40 (T _1: the toner becomes 10 ⁵ poise temperature, T _2: temperature coating layer member becomes 10 ⁵ poise) image forming method for fixing heating roll has been proposed under the conditions satisfying the.

[0009]

According to the technique (A), a color image having a certain level of gloss and good image quality can be provided, but the resin used for forming the transparent resin layer is not used here. Since it is an acrylic resin having a softening point of 60 to 70 ° C., the adhesiveness increases when heated and melted, and the image is peeled off from the transparent resin layer and adhered or transferred to the heating roller, causing the image to be missing or the heating roller to be removed. Again, and contaminates the image. In addition, the formed color image softens and has an adhesive property under a relatively high temperature environment of about 30 ° C. Therefore, when another paper or the like is superimposed on the image, the color image does not peel off due to adhesion. Are transferred, and the preservability of the image is remarkably inferior. In addition, the technology (B)
In this case, the toner has a softening point higher than that of the resin layer and is buried in the resin layer. It is difficult to completely bury the toner in the resin layer, and the smoothness of the surface is poor.

In the above techniques (A) and (B),
Because the heat roller fixing method using only rollers is used,
The time until contact and separation after contact heating is short, and the toner is not completely melted but is in the state of a rubbery elastic body,
Although it is elastically deformed by the pressure of the heating roller and becomes smooth, when the pressure is released, it returns to its original state, and the toner particles do not reach the same surface state as the contacting heating roller, and the toner particles are not formed. It will be in a raised state,
Also, at the stage of separation in which the toner image is peeled off from the heating roller, the fused toner has an adhesive property with the heating roller, and the fixing toner image is lifted by being pulled by the heating roller in a direction along the surface of the image. In addition, there is a problem that the glossiness of the color image is inferior due to the unevenness of the surface.

Further, in the above technique, special paper having a transparent resin layer provided on an image support in advance must be manufactured. The special paper is usually produced by dissolving a resin for forming a transparent resin layer in a solvent, applying the solution on an image support, and then drying. Therefore, for the production of special paper, a wet process using a solvent and a coating technique for performing uniform coating are required, and a special manufacturing process and technique are required, resulting in an increase in cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a color image forming method capable of providing a glossy high-quality color image. It is another object of the present invention to provide a color image transfer member and a color image forming method which do not cause image loss or contamination by a heat fixing device. It is another object of the present invention to provide a color image forming method having good storability of a color image. Another object of the present invention is to provide a color image forming method capable of using plain paper that does not require special paper. Another object of the present invention is to provide a high-quality full-color image forming method having a transparent resin layer by a simple method that does not require a solvent in order to form a transparent resin layer on an image support. .

[0013]

An object of the present invention is to use thermoplastic transparent resin particles for forming a transparent resin layer on an image transfer member and three or more kinds of color toners using a thermoplastic resin as a binder. forming a transparent resin layer on a forming basil Kara <br/> Tona image by an electrophotographic method on a photosensitive member, <br/> color toner formed on the photoreceptor subsequent to the image transfer member A step of transferring an image, a step of heating and fixing an image transfer body having a color toner image by a belt-shaped member,
The step of transporting the belt-shaped member in contact with the belt-shaped member, and the step of separating the belt-shaped member from the image transfer body, the softening point of the color toner is from the softening point of the resin constituting the thermoplastic transparent resin particles It can be achieved by a color image forming method characterized in that it is low.

That is, according to the present invention, after a color toner image is formed on a photoreceptor, a resin particle layer for forming a transparent resin layer on the color toner image is formed on the photoreceptor by the same electrophotographic method as the toner. Formed on the outermost surface of the toner image. The toner image formed on the photoreceptor is transferred onto the transfer body. At this time, when the uppermost resin particle layer on the photoreceptor is transferred, it will be located on the lowermost layer on the transfer body, The color toner image is located in the surface of the particle layer. When this is heated and fixed by a belt-shaped member for a relatively long time,
The resin particle layer melts to form a uniform transparent resin layer, while the color toner has a lower softening point than the resin particles, so it is easier to melt than the resin particles. While exhibiting a good color tone,
The transparent resin layer is different in cross-linking structure and resin type, so it does not melt and mix with the toner, does not cause reproducibility degradation due to image spread at the fixing stage, and has smooth and high quality color images without unevenness Can be provided. Here, since the resin particles are smaller than the particle diameter of the color toner, the transparent resin layer can be formed by preventing toner particles from being mixed in the particle layer forming the transparent resin particle layer.

Further, a process for forming a transparent resin layer is introduced into a process for forming a color toner image, and a normal electrophotographic process is used. Therefore, the use of plain paper which does not require special paper is required. It is possible to easily form a transparent resin layer without the need for complicated manufacturing processes and equipment such as a special coating process, a solvent-based wet process and a drying process for forming a transparent resin layer on an image support. A high-quality full-color image having the following characteristics can be formed.

The resin constituting the resin particles for forming the transparent resin layer of the present invention is composed of a monomer selected from a styrene monomer and an acrylic monomer. Such monomers include styrene, styrene monomers such as α-methylstyrene, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, dodecyl acrylate, lauryl acrylate, acrylic acid- 2-
Ethylhexyl, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, methyl methacrylate,
Examples include acrylic monomers such as ethyl methacrylate, propyl methacrylate, butyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate. Further, the use of a cross-linking agent such as divinylbenzene or diethylene dimethacrylate is effective for improving the releasability from a belt and the preservability of a color image. As a method for producing such resin particles, the suspension particles can be easily produced by using a suspension polymerization method. Water can be used as a dispersion medium in the suspension polymerization method, an inorganic salt such as tricalcium phosphate can be used as a dispersant, and a surfactant such as sodium dodecylbenzenesulfonate can be used as a dispersion aid.

The volume average particle size of the resin particles is 3.0 to 8.0 μm.
m, and is preferably smaller than the volume average particle diameter of the color toner, particularly at least 2.0 μm.
The volume average particle diameter of the resin particles and the toner in the present invention is measured by, for example, a Coulter counter.

The transparent resin layer formed by the resin particles is provided on the surface of a transfer substrate made of, for example, paper, plastic, or the like, with a thickness of 10 to 80 μm, preferably 15 to 40 μm, to provide a high quality color. Preferred for providing images. When the thickness of the transparent resin layer is less than 20 μm, it is difficult to provide a sufficient transparent layer under the color toner image when the color toner image is melted and fixed, and it is difficult to obtain a good color tone. On the other hand, when the thickness of the transparent resin layer exceeds 80 μm, the color toner image and the transparent resin layer tend to transfer to, for example, a belt-shaped heating element, causing image loss and surface irregularities, resulting in glossiness. A poor color image is obtained.

The softening point of the resin particles is preferably from 110 to 150 ° C. in order to melt and form a uniform transparent resin layer.

[0020]

Next, the color image forming method of the present invention will be described.

The color developer used in the present invention is preferably a two-component color toner composed of a non-magnetic color toner and a magnetic carrier from the viewpoint of improving fluidity, triboelectricity, developability, image reproducibility and the like. Color developers are preferably used.

The non-magnetic color toner is formed of colored resin particles composed of a binder resin, a colorant, and if necessary, a charge control agent and other property improving agents, or may be formed of an inorganic material, if necessary. It is constituted by adding and mixing oxide fine particles from the outside.

As the binder resin, styrene-
Acrylic resin, styrene-butadiene resin, polyester resin, etc. can be used, but the incompatibility with the transparent resin layer of the color image transfer body is improved to give the spread of the image after fixing and the sharpness of the boundary area For this purpose, it is preferable that the polyester resin be contained in a proportion of 50% by weight or more.

The colorants include carbon black as BK (black) toner, phthalocyanine blue as C (cyan) toner, and benzidine yellow, quinoline yellow, chromophthal yellow, and M (magenta) as Y (yellow) toner. ) As the toner, commonly used toners such as Chromophtal Red and PV Fast Red can be used.

As the charge control agent, a metal complex salt of a monoazo dye, a metal complex with a carboxylic acid compound, a quaternary ammonium salt compound, a nigrosine dye, and the like can be used.

As the other property improving agent, a low molecular weight wax having a number average molecular weight of 2,000 to 6,000 such as paraffin wax, polyethylene wax and polypropylene wax can be used in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the binder resin. .

As the above-mentioned inorganic oxide fine particles, silica, titanium oxide or the like, which has been subjected to a hydrophobizing treatment with a silane coupling agent, can be added to and mixed with the toner at a ratio of 0.2 to 3% by weight.

The softening point Tsp (t) of the color toner of the present invention is
Make sure that the color toners of each color mix well in the molten state
It is preferably 90 to 140 ° C., and the softening point Ts of the resin particles so as not to be mixed with the transparent resin layer in a molten state.
It is preferably lower than p (p), furthermore at least 5 to 30
It is preferable that the temperature is lower by ° C.

That is, Tsp (t) <Tsp (p), 90 ° C. <Tsp (t) <14
0 ° C., and Tsp (p) −5 <Tsp (t)
<Tsp (p) -30 is preferred.

In the present invention, the softening points of the resin particles and the toner are measured using a flow tester (CFT500, manufactured by Shimadzu Corporation) under the conditions of a load of 20 kg / cm ² , a nozzle diameter of 1 mm, a nozzle length of 1 mm, Preheating at 80 ° C for 10 minutes, at a heating rate of 6 ° C / min, and a sample volume of 1 cm ³ (true specific gravity x 1 cm ³
When the height of the S-shaped curve in the plunger descent amount-temperature curve (softening flow curve) of the flow tester is h, the temperature is h / 2.

As the magnetic carrier, magnetic particles such as iron, ferrite, magnetite or the like, or styrene-acrylic resin, silicone resin,
Coated magnetic particles coated with a fluororesin or the like can be used.

In the color image forming method of the present invention, the color toner image formed on the photoreceptor and the resin particles for forming the transparent resin layer formed on the photoreceptor are transferred to an image transfer member, which is heated, melted and fixed. When a color image is formed, the image is fixed by a belt-shaped heating and conveying member to form a color image.

According to this configuration, since the color image transfer body is heated even during the conveyance of the belt-shaped heating conveyance body, it is heated for a much longer time than the fixing system using only the heating roller. In addition, the resin particles can be sufficiently melted to form a transparent resin layer, and the color toner particles can be completely fluidized, so that the toners of the respective colors are sufficiently mixed. Further, even at the time of releasing, the releasability of the belt-shaped heat transfer body from the color image transfer body and the color toner image is good, so that the image is not lost due to the floating or transfer of the color toner image. For this reason, the obtained color image is excellent in glossiness by preventing irregular reflection of illumination light, and has high quality and good storability without the image adhering to the belt-shaped heating and conveying member.

FIG. 1 (a) shows a light reflection state when there is no transparent resin layer, and FIG. 1 (b) has a transparent resin layer and a fixed color toner image is formed on the transparent resin layer. The light reflection state when embedded inside is shown. In FIG. 1, reference numeral 1 denotes a transfer body made of plain paper, 2A denotes a fixed color toner image, and 2B denotes a transparent resin layer.

As is apparent from FIG. 1B, when the fixed color toner image 2A is embedded in the transparent resin layer 2B and the surface is smooth, there is no light scattering and the reflection is good. A color image having good gloss can be obtained.

FIG. 2 shows an example of a fixing device which can be suitably used for fixing a color toner image and a resin particle layer formed on a color image transfer body of the present invention. In the fixing device shown in FIG. 2, the transparent resin particle layer and the color toner on the surface of the color image transfer member are heated and melted by a belt-shaped heating / transporting member that moves under a member containing a heat source, and then cooled. The color image transfer body can be separated from the belt-shaped heat transfer body to form a color image.

In FIG. 2, the heating roll 3 is constituted by providing an elastic layer 5 of rubber or the like on the outer periphery of a core fixed to a rotating shaft, and has a heat source 6 such as an infrared lamp inside. 7 is a pressure roll, 8a is an upper heat-resistant belt, and 8b is a lower heat-resistant belt. These heat resistant belts 8a, 8b
Is formed by treating the surface of a heat-resistant resin such as polyimide with a silicone resin. 9 is a peeling roll, 10
Is a pressure roll for the release roll. Reference numeral 11 denotes a separation claw of the transfer body 1 provided as needed, and reference numeral 12 denotes a forced cooling device provided as needed.

In the fixing device shown in FIG. 2, the transfer body 1 carrying the color toner image 2A and the resin particle layer 2B is
Is heated and conveyed by the heat-resistant belts 8a and 8b moving below the member having the color toner image 2A on the transfer body 1.
The resin particles 2B are melted and fixed, and cooled by natural air cooling or a forced cooling device 12 so as to be hardly deformed. According to such a fixing device, a sufficient fixing property and an extremely smooth color image can be obtained.

In the color image forming method of the present invention,
An image is exposed on a photoreceptor to form an electrostatic latent image for each color, and the latent image is developed by superimposing with Y, M, C, and BK toners and finally with resin particles to form a color toner image. Next, the superimposed color toner image and the resin particle layer are collectively transferred onto a transfer body, and this is heated and fixed to form a color image.

FIG. 3 is a sectional view of a color image forming apparatus which can be used in the color image forming method of the present invention, where K is an image reading section, L is a laser writing section, and M is a laser writing section.
Denotes an image forming unit, and N denotes a sheet feeding unit.

The image reading section K includes a carriage 22 on which a mirror 25 and a halogen lamp 24 are mounted, a movable mirror unit 23 on which mirrors 26 and 27 are mounted, a lens
30, a color CCD 33, and an image processing device 34.

The laser writing section L comprises a motor 41, a polygon mirror 42 and the like.

The image forming section M includes a photosensitive member 40 made of, for example, an organic photoconductive semiconductor material, a pre-exposure lamp 45A, a scorotron charger 45B, and Y, M, and AC to which an AC bias P1 and a DC bias P2 are applied. Developing machines 46Y and 46 filled with a developer containing negative toners of C and BK and resin particles.
M, 46C, 46BK, and 46W, a transfer unit 47 that collectively transfers the color toner image formed on the photoconductor 40 to the transfer body PA or PB, a separator 48, and a fixing unit 55 that fixes the color toner image. The cleaning device 49 removes toner remaining on the photoconductor 40. The fixing unit 55 is shown in FIG.
The configuration is the same as that shown in FIG.

The paper supply section N has delivery rollers 51A and 51B for delivering the transfer material PA or PB from the paper supply cassette 50A or 50B to the transfer device 47 and the separator 48, and a timing roller 52.

The color image forming method of the present invention can be carried out as follows using the color image forming apparatus configured as described above.

That is, the start button is turned on, an initialization signal is output to the image reading section K via the control circuit, and the color separation filter device 32 sets the B filter.

In the first rotation of the photosensitive member 40, the document 20 on the document table 21 of the image reading section K is optically scanned by the halogen lamp 24 of the carriage 22, and the mirror group 25, 26, 27 driven by a stepping motor. A light image of the original is formed on the light receiving surface of the color CCD 33 through the lens 30 via the lens 30 and is converted into an electric signal.

The obtained electric signal is subjected to signal processing such as A / D conversion, shading correction, gradation correction, masking, ghost processing, and multi-value processing in the image processing device 34.
The image data of Y, M, C, and BK is created. Then, the Y image signal as the first color signal is output to the next laser reading unit L.

A laser beam oscillated from a laser light source is pulse-width-modulated by the Y image signal, is rotationally scanned by a polygon mirror 42 rotationally driven by a motor 41, and is bent by a mirror 44 via an fθ lens 43. Then, image exposure is performed on the surface of the photoreceptor 40 to which pre-exposure is preliminarily performed by the pre-exposure lamp 45A and uniformly charged by the charger 45B to form an electrostatic latent image.

Next, the electrostatic latent image is reversibly developed in a non-contact manner by a developing unit 46Y to form a Y toner image. While holding the obtained Y toner image on the photoconductor 40,
The photosensitive member 40 is conveyed to the charger 45B with the second rotation of the photosensitive member 40 to form the next M toner image in order to form the next M toner image.

The surface of the photoconductor 40 carrying the Y toner image is uniformly negatively recharged by the charger 45B, and then the second image from the image processor 34 is scanned by the image reading section K. By performing image exposure of a laser beam based on an M image signal that is a color signal, an electrostatic latent image is formed on the photoconductor 40,
This is subjected to non-contact reversal development by the developing unit 46M to form a superposed M toner image on the Y toner image.

In the same manner, the third and fourth photoconductors 40
In the fifth time, image exposure of the laser beam based on the C image signal, development by the developing unit 46C, image exposure of the laser beam based on the BK image signal, and development by the developing unit 46BK are performed. In the same manner as above, the non-contact reversal development of the resin particles by the developing device 46W without exposure is performed, and then the Y toner image on the photoconductor 40, the C toner image on the M toner image, and the C toner image on the photoconductor 40 are exposed. BK toner image, B
The color toner image and the resin particle layer are formed by superimposing the resin particle layer on the K toner image.

The obtained color toner image and the resin particle layer are
At the same time as the image formation, the sheet is conveyed from the cassette 50A to the transfer area via the feed roller 51A and the timing roller 52, and is transferred onto the color image transfer body PA of the present invention.
Batch transfer by the action of

Transfer member PA on which a color toner image has been transferred
Is separated from the photoreceptor 40 by a separator 48, and is conveyed to a fixing device 55 by a conveying belt 54, and is heated and fixed by the fixing device 55 (see FIG. 2) to form a color image.
To discharge to the discharge tray 57.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

Example-1 <Production of Transparent Resin Particles> 30% by weight of a monomer component composed of styrene / butyl acrylate / divinylbenzene (weight composition ratio: 80: 19.5: 0.5) was added to 3% by weight of an inorganic salt, tricalcium phosphate. % Of a dispersing agent, and 0.03% by weight of a surfactant, sodium dodecylbenzenesulfonate, as a dispersing aid. "Resin particles-A" was obtained.

<Preparation of Developer> Polyester resin (bisphenol A propylene oxide / terephthalic acid / fumaric acid, weight composition ratio, 50:25:25) 100 parts by weight Colorant (carbon black) 10 parts by weight Polypropylene (number average molecular weight) , 4000) 3 parts by weight The above materials were melt-kneaded, pulverized, and classified to prepare a BK toner having a softening point of 112 ° C. and an average particle diameter of 8 μm.

The softening point was the same as in the above BK toner except that the colorants were changed to benzidine yellow 5 parts by weight rhodamine B 5 parts by weight copper phthalocyanine 5 parts by weight, respectively.
Y toner, M toner and C toner having an average particle size of 8 μm at 112 ° C. were prepared.

By mixing 5 parts by weight of the resin particles and 5 parts by weight of the four types of color toners with 95 parts by weight of a spherical ferrite carrier coated with a styrene-methyl methacrylate copolymer, five types of developers (resin layer) were obtained. (For forming and for full color).

<Evaluation of Color Image> Using these developers, a color image was formed on plain paper by the color image forming apparatus of FIG. 3 equipped with the belt-shaped fixing device of FIG. The main conditions are as follows.

Charge potential of photoreceptor: -700 V AC bias voltage P1: 2 kV, 3 kHz DC bias voltage P2: -550 V Development method: specific contact reversal development Environmental condition: 20 ° C., relative humidity 60% RH There was no transfer to the heating carrier and no image was lost, and the color tone was good and the image quality was high. The glossiness of this color image was 78%. In addition, the glossiness is "UGS-300A variable angle gloss meter" [Nippon Denshoku Industries
(Manufactured by K.K.) at a measurement angle of 75 degrees. The thickness of the transparent resin layer was 38 μm.

Next, the formed color images are superimposed face-to-face, a load of 0.5 g / cm ² is applied thereto, and the images are stored for one day in an environment of a humidity of 40 ° C. and a relative humidity of 80%. A sex test was performed. As a result, no image was attached and the storability was good.

Example 2 <Production of Transparent Resin Particles> In the production of “Resin Particles-A”, the monomer component was styrene / methyl methacrylate / butyl acrylate / divinylbenzene (weight composition ratio, 6
7: 10: 22.7: 0.3) to obtain “Resin Particle-B” having an average particle size of 2.0 μm and a softening point of 123 ° C. in the same manner as in Example 1 except that the monomer component was replaced.

<Preparation of Developer> and <Evaluation of Color Image> A developer was prepared and a color image was formed in the same manner as in Example 1 except that “resin particles-A” was replaced with “resin particles-B”. An evaluation was performed. The obtained image had no transfer to the belt-shaped heating / transporting body or lack of the image at all, and had good color tone and high image quality. The glossiness of this color image was 81%. The thickness of the transparent resin layer was 23 μm. As a result of the storage test, no image was attached and storage stability was good.

Example 3 <Production of Transparent Resin Particles> In the production of “Resin Particles-A”, the monomer component was styrene / methyl methacrylate /
Butyl acrylate / divinylbenzene (weight composition ratio,
77: 5: 17.7: 0.3), and "Resin Particle-B" having an average particle size of 4.0 μm and a softening point of 128 ° C. was obtained in the same manner as in Example 1 except that the monomer component consisting of (77: 5: 17.7: 0.3) was used.

<Preparation of Developer> and <Evaluation of Color Image> A developer was prepared and a color image was formed in the same manner as in Example 1 except that “resin particles-A” was replaced with “resin particles-B”. I got an evaluation.

The obtained image had no transfer to the belt-shaped heating / transporting member or lack of the image at all, and had good color tone and high image quality. The glossiness of this color image was 79%. The thickness of the transparent resin layer was 32 μm. As a result of the storage test, no image was attached and storage stability was good.

Comparative Example 1 A methyl methacrylate-butyl acrylate copolymer having a softening point of 70 ° C. was dissolved in an acetone solvent at a concentration of 20% by weight, applied to an A4 size plain paper with a wire bar, dried, and dried at 20 μm. A comparative transfer member a having a thick transparent resin layer was prepared. In Example 1, the transfer member and the comparative transfer member a were changed to a heat roller fixing device as a fixing device,
In addition, the evaluation was performed in the same manner as in Example 1 except that the step of forming the resin particle layer using the resin particles-A in Example 1 was performed, and a part of the obtained image was transferred to a belt-shaped heating and transporting body. However, an image was missing, and the gloss was 35%, which was poor in gloss. Also, in the preservation test, when the images adhered to each other and were forcibly separated, one image transferred from the other.

[0069]

As is apparent from the above description, according to the color image forming method of the present invention, it is possible to obtain a color image having excellent gloss, high quality and excellent storage stability.

[Brief description of the drawings]

FIG. 1A is an explanatory view showing a light reflection state when a transparent resin layer is not provided, and FIG. 1B is an explanatory view showing a light reflection state when a transparent resin layer is provided.

FIG. 2 is a cross-sectional view illustrating an example of a fixing device that can be suitably used in the present invention.

FIG. 3 is a cross-sectional view of the color image forming apparatus used in the embodiment.

[Explanation of symbols]

 Reference Signs List 1 transfer body 2A color toner image 2B transparent resin particle layer 3 heating roll 4 core 5 elastic layer 6 heat source 7 pressure roll 8a heat resistant belt 8b heat resistant belt 9 peeling roll 10 pressure roll 11 separation claw 12 forced cooling device 20 document 21 document Table 22 Carriage 23 Movable mirror unit 24 Halogen lamp 30 Lens 33 Color CCD 34 Image processing device 41 Motor 42 Polygon mirror 43 fθ lens 45A Pre-exposure lamp 45B Scorotron charger 46Y Yellow developing unit 46M Magenta developing unit 46C Cyan developing unit 46BK Black developing Unit 46W resin particle developing unit 47 transfer unit 48 separator 49 cleaning unit 55 fixing unit PA color image transfer unit PB color image transfer unit K image reading unit L laser writing unit M image forming unit N paper feeding unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/01 G03G 15/20 G03G 7/00 G03G 9/09

Claims (1)

(57) [Claims] 1. A method for forming a transparent resin layer on an image transfer member by using thermoplastic transparent resin particles and three or more types of color toners using a thermoplastic resin as a binder.
A color toner image is formed by electrophotography and transparent on it
Forming a resin layer , and subsequently forming the resin layer on the image transfer body .
A step of transferring a color toner image formed on an optical body, a step of heating and fixing an image transfer body having a color toner image by a belt-shaped member, a step of transporting the image transfer body in contact with the belt-shaped member, and an image transfer A color image forming method comprising the step of separating a body and a belt-shaped member, wherein a softening point of the color toner is lower than a softening point of a resin constituting the thermoplastic transparent resin particles.