JPH11119473A - Image forming method and developer used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a toner image without causing a void and printing unevenness in a pattern printed on the surface of a heat-resistant solid, onto a transfer sheet by specifying the true specific gravity ratio of carriers to toner (the carriers/the toner). SOLUTION: An electrostatic latent image on an image carrier is developed with the toner colored after printing is executed and the obtained toner image is transferred to the transfer sheet from the image carrier, so that the toner image is formed on the transfer sheet. At this time, the true specific gravity ratio of the carriers in a developer to the toner colored after the printing is executed (the carriers/the toner) is set 2-3. Thus, gaps in the toner in an unfixed toner image on the transfer sheet are reduced and the gaps in the toner image fixed on the transfer sheet can be further reduced. Thus, the toner image for the pattern, fixed on the transfer sheet in the above-mentioned manner can be stuck/printed on the surface of a heat-resistant solid, so that the pattern not having the void and the printing unevenness can be formed on the surface of the heat-resistant solid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for developing an electrostatic latent image on an image carrier with a color toner after baking, and transferring the resulting toner image from the image carrier to a transfer sheet. Image forming method for forming a toner image on the
In particular, the present invention relates to an image forming method for forming a toner image with a colored toner after firing on a transfer sheet for painting on a heat-resistant solid surface such as ceramic, glass, enamel, tile, and stone. Further, the present invention relates to a developer used in the image forming method.

[0002]

2. Description of the Related Art As a method of forming a pattern on a heat-resistant solid surface of a ceramic product or the like, a pattern made of an inorganic pigment and a glaze component is used, and a pattern is directly written on the heat-resistant solid surface with a brush or the like, and the pattern is drawn. Usually, a method of baking at 750 ° C. to 1300 ° C. is performed. According to this method, by baking, the components to be incinerated in the paint are ashed, the glaze component in the paint is dissolved, and when cooled to room temperature, the inorganic pigment is fixed to the heat-resistant solid surface by the glaze component And
A handwritten pattern is formed on the heat-resistant solid surface. According to this method, skilled workers are required even for simple patterns in order to obtain a plurality of ceramic products having the same pattern. Therefore, when producing a large number of ceramic products with the same pattern, after forming a pattern on transfer paper by screen printing, peel off the pattern from the transfer paper, paste it on the ceramic product surface, and bake it The method is generally performed.

This method is disclosed, for example, in Japanese Patent Application Laid-Open No. 49-354.
As disclosed in JP-A-07-07, an image is formed on a transfer paper having a water-soluble glue layer on a substrate by an ink containing an inorganic pigment or the like by a screen printing method, and then a vinyl-based image is formed on the ink image. Alternatively, after forming a cellulose-based water-insoluble resin film, the transfer paper is immersed in water to dissolve the adhesive layer of the transfer paper, and the resin film holding the ink image is peeled from the transfer paper to retain the ink image. This is a method in which the obtained resin film is attached to the surface of a ceramic product, for example, the surface of a dish or the like, and is baked. A large number of transfer papers with the same pattern of ink images are created by screen printing, and the ink images are attached to a number of ceramic product surfaces and baked to obtain a large number of ceramic products with the same pattern. it can. However, in the case of using the screen printing method, there are a plurality of steps of making a plate for forming an ink image for a picture, which requires an enormous amount of time and labor,
In addition to lack of immediacy, there is a drawback that the unit price per product is high when producing a large variety of products in a small lot. Further, since an organic solvent is used at the time of printing, there are disadvantages such as a poor working environment.

[0004] As a method for solving the problems caused by the screen printing method, a toner (a composite powder comprising an organic polymer, an inorganic pigment and a glass component, a binder resin, and a pigment for ceramics) is transferred onto transfer paper by electrophotography. A method of forming an image for a pattern using a toner containing the same, affixing a resin film holding the toner image to the surface of a ceramic product, and baking it is disclosed in, for example, JP-A-4-135798 and JP-A-Hei. 7-199540, JP-A-7-21
JP-A-4890, JP-A-7-228037, JP-A-7-300382, JP-A-8-104050, JP-A-8-11496, JP-A-8-119
No. 668, for example. According to this method, a toner image for a picture can be easily formed,
The process is dramatically simplified as compared with the screen printing method, and it is excellent in immediacy and can easily produce a product of a small lot and many kinds.

[0005]

However, a toner image for a picture formed on a transfer paper by electrophotography is pasted on a heat-resistant solid surface of a ceramic product or the like, and then baked, the image is printed on the heat-resistant solid surface. However, there is a problem in that a blank image or uneven printing occurs which does not occur when the screen printing method is applied to the obtained pattern. Therefore, an object of the present invention is to solve such a problem, an image forming method for forming a toner image on a transfer sheet without causing white spots or uneven printing on a pattern printed on a heat-resistant solid surface,
In particular, it is an object of the present invention to provide an image forming method for forming a toner image on a transfer sheet for painting for painting on a heat-resistant solid surface with a colored toner after baking, and a developer used in the image forming method. .

[0006]

According to the present invention, first, an electrostatic latent image on an image carrier is developed with a developer composed of a carrier and a color toner after baking, and the resulting image is obtained. Forming the toner image on the transfer sheet by transferring the toner from the image carrier to the transfer sheet, wherein the true specific gravity ratio (carrier / toner) of the carrier and the toner is set to 2-3. A method is provided.

Secondly, there is provided an image forming method according to the first aspect, wherein a toner image is transferred from an image carrier to a transfer sheet via an intermediate transfer belt.

Third, the image forming method according to the first or second aspect, wherein the transfer sheet is a transfer paper sheet for painting for painting on a heat-resistant solid surface. Provided.

Fourthly, there is provided an image forming method according to the third aspect, wherein the transfer sheet has a water-soluble layer, and the toner image is transferred onto the water-soluble layer. .

Fifth, in the image forming method according to any one of the first to fourth aspects, the toner image is formed with at least one of four color toners of yellow, magenta, cyan, and black. An image forming method is provided.

Sixthly, there is provided an image forming method according to any one of the first to fifth aspects, wherein the color toner after firing contains an alloy pigment.

Seventhly, in a developer comprising a carrier and a toner which is colored after baking, the true specific gravity ratio (carrier / toner) of the carrier and the toner is 2-3. Is provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. After baking, the toner image for the pattern formed on the transfer sheet by the colored toner is peeled off together with the resin film formed on it and attached to the heat-resistant solid surface of ceramic products, etc. and baked. In this case, it was observed that, when the printing temperature was around 200 ° C. to 400 ° C., white spots and uneven printing which did not occur in the case of the screen printing method occurred.

As a result of studying the cause, the difference between the ink image formed on the transfer sheet formed by the screen printing method and the toner image formed on the transfer sheet formed by the electrophotographic method is that a gap is substantially formed in the ink image. In contrast to this, voids may be present in the toner image layer formed by the toner particles, and the presence of these voids causes bumping, which causes the pattern printed on the surface of the heat-resistant solid to have white voids. It became clear that uneven baking occurred.

That is, when a resin film holding a toner image is attached to a heat-resistant solid surface and baked, the baking temperature is about 200 ° C. to 400 ° C.
When the thermoplastic resin and the resin film in the toner change from a solid to a liquid by increasing the temperature and decrease in viscosity, the air existing in the voids in the toner image layer expands, or the toner image is formed by immersing the transfer sheet in water. In the process of peeling the resin film holding the toner from the transfer sheet, the water that has entered the voids in the toner image layer evaporates and expands, causing a bumping phenomenon. It is clear that will occur.

Further, as a result of examining the cause of the occurrence of voids in the toner image layer formed of the toner particles on the transfer sheet, the toner is repelled where toners of the same polarity overlap, so that the voids are formed. It turned out to happen. That is, in the developed toner image on the electrophotographic photosensitive member, the electric repulsive force between the toners is suppressed by the background potential on the photosensitive member, but the toner image transferred on the intermediate transfer belt and the transfer paper. In the above, since the background potential as in the toner image on the photoconductor does not act, the electric repulsion between the toners of the same polarity acts, and the gap is larger than in the toner image on the electrophotographic photoconductor. It became clear.

Finally, since the toner image transferred onto the transfer sheet is fixed by the action of heat and pressure of the fixing roller, the voids in the fixed toner image layer are considerably reduced. To reduce voids in the image layer,
Reduce the gap between the toners in the unfixed toner image on the transfer sheet, or reduce the gap between the toners in the toner image on the intermediate transfer belt and between the toners in the unfixed toner image on the transfer sheet. It has been found that the true specific gravity ratio (carrier / toner) between the carrier in the developer and the colored toner after baking may be adjusted to 2-3.

That is, according to the present invention, the electrostatic latent image on the image carrier is developed with a colored toner after baking, and the obtained toner image is transferred from the image carrier to the transfer sheet to be transferred onto the transfer sheet. In the image forming method for forming a toner image on a transfer sheet, if the true specific gravity ratio (carrier / toner) between the carrier in the developer and the colored toner after firing is set to 2 to 3, the toner in the unfixed toner image on the transfer sheet The gap between the toner image layers fixed on the transfer sheet by the action of heat and pressure of the fixing roller can be further reduced. Then, the toner image for the pattern fixed on the transfer sheet in this manner is attached to the heat-resistant solid surface, and the pattern is baked to form a pattern free from white spots and uneven printing on the heat-resistant solid surface. it can.

When the true specific gravity ratio between the carrier in the developer and the toner that is colored after baking is smaller than 2, the amount of adhered toner increases, causing white spots and uneven printing in printing a toner image on a heat-resistant solid surface. Easier to do. Also, when the true specific gravity ratio exceeds 3, background contamination may occur. The true specific gravity ratio is particularly preferably 2.2 to 2.6.
When a developer having a true specific gravity ratio within this range is used, almost no voids are generated in the toner image layer, so the toner image for a pattern fixed on the transfer sheet is attached to the heat-resistant solid surface, and By baking, it is possible to form a good sintered pattern without white spots and uneven printing on the surface of the heat-resistant solid.

In the present invention, the true specific gravity ratio between the carrier and the colored toner after firing is a value obtained by dividing the true specific gravity of the carrier by the true specific gravity of the colored toner after firing. The true specific gravity of the carrier and the toner is measured based on JIS Z 8807.

Next, the colored toner after firing used in the present invention will be described. The toner that is colored after firing is a toner that contains a colorant that does not incinerate when heated to 450 ° C. or higher. Colored toners after firing include, for example, Cu, Ag, Au, and Group 2 of the periodic table.
Group Cd, group 4 Ti, group 5 V, Sb, group 6 Se,
Cr, Mo, W, U, Mn of Group 7, Fe, Co of Group 8,
It contains a coloring agent such as a pigment for ceramics and a thermoplastic resin which are used alone or in combination (mixed) with oxides of elements such as Ni, Ir and Pt. Conventional ceramic pigments generally have a low absorption coefficient of the pigment itself.To form a full-color image with a high image density using a toner containing these ceramic pigments as a colorant, it is necessary to increase the toner adhesion amount. is necessary.

As a colorant in the toner which is colored after firing, a plurality of the above-mentioned metals or oxides thereof are blended (mixed), and the mixture is heated to 1000 to 1200 ° C. to be melted and subjected to an alloying treatment of a plurality of metals. Particularly preferred are alloyed pigments. This alloy pigment has a high absorption coefficient, and by using a toner containing this pigment as a colorant, a full-color image having a high image density can be formed with a small amount of toner adhered. The cause of the increase in the degree of coloring due to alloying of multiple metals is that the d orbitals of the metal element, which had been degenerated at the time of a single metal, split due to the influence of the composite metal, and the number of orbitals capable of electron transition increased. It is presumed that this is because the apparent oscillator strength increases.

As the thermoplastic resin, a binder resin component used in a conventionally known toner can be used. Examples thereof include polyester, polystyrene, polyethylene, polyamide, epoxy, epoxy polyol, and terpene. And the like, and these can be used alone or as a mixture. Specifically, for example, polystyrene, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
An n-butyl copolymer and the like can be mentioned. The content of the thermoplastic resin in the toner is 10 to 50% by weight.
Is preferred.

Further, the toner which is colored after firing is
It is preferred to use a glaze frit with a colorant and a thermoplastic resin. As a method of including a glaze frit in the toner, for example, a method using a mixture of a colorant and a glaze frit, a mixture of a colorant and a glaze frit is heated and melted, then cooled, and then crushed to obtain a colorant. There are methods used. In particular, it is particularly preferable to mix a predetermined amount of the alloy pigment and the glaze frit that have been subjected to the alloying treatment of a plurality of metals, heat and melt the mixture at, for example, 650 to 800 ° C., cool it, and pulverize it and use it as a colorant. .

By using a toner containing such a coloring agent, a clear full-color image having a high image density and a high image density can be formed on a transfer sheet with a small amount of toner adhered, and the toner image can be formed on a heat-resistant product such as a ceramic product. By transferring the image onto the solid surface and printing it, it is possible to form a sharp printed pattern having a high image density on the heat-resistant solid surface.

The content of the glaze frit in the toner is from 2/8 to the weight ratio of the colorant and the glaze frit.
It is preferably 6/4, particularly preferably 3/7 to 5/5. Increasing the glaze frit component from 2/8 lowers the degree of coloring of the toner, and reducing the glaze frit from 6/4 reduces the baked pattern to the heat-resistant solid surface when the toner image is printed on the heat-resistant solid surface. In some cases.

The glaze frit plays a role of sintering the colorant in the toner on the heat-resistant solid surface when printing the toner image transferred onto the heat-resistant solid surface. Then, when cooled to room temperature, it is completely solidified, and the colorant is sintered on the heat-resistant solid surface.

Examples of the glaze frit include hydroxides of alkali metals and alkaline earth metals such as lithium hydroxide, carbonates of alkali metals and alkaline earth metals such as lithium carbonate, and the like.
Alkali metal or alkaline earth metal chloride, aluminum chloride, boric acid, alkali metal or alkaline earth metal chloride borate, alkali metal or alkaline earth metal chloride metaborate, alkali metal or alkali Earth metal phosphate, alkali metal or alkaline earth metal pyrophosphate, alkali metal or alkaline earth metal silicate, alkali metal or alkaline earth metal metasilicate, zirconium silicate, bone ash, borax Metal oxides such as ammonium metavanadate, tungsten oxide or vanadium pentoxide, tin oxide, zirconium oxide, cerium oxide, molybdenum oxide, metal fluorides such as calcium fluoride and aluminum fluoride, glasslets, etc. These may be used alone or in combination.

As a method of strengthening the binding of the glaze frit,
Feldspars such as lime feldspar, potassium feldspar, soda feldspar, betalite (lithium feldspar), kaolin, quartzite, alumina, silica, quartz, titanium oxide, lead oxide, chamotte, earth ash,
As a basic material, natural minerals such as limestone, magnesite, talc, and dolomite, and barium carbonate, zinc oxide, strontium carbonate, and the like may be mixed in advance, dissolved, and then contained in the toner.

Furthermore, the toner which is colored after firing is
A charge control agent can be contained. As such a charge controlling agent, any conventionally known ones can be used, and examples thereof include nigrosine dyes, quaternary ammonium salts, Cr-containing dyes, Zn-containing dyes, Fe-containing dyes, molybdate chelate dyes, and fluorine-containing dyes. A modified quaternary ammonium salt or the like is appropriately selected and used according to the charging polarity.

The amount of the charge control agent used depends on the type of thermoplastic resin, the presence or absence of additives used as necessary, and the method for producing the toner including the method of dispersion in the toner. The range of 0.1 to 10 parts by weight relative to part by weight is appropriate, and particularly preferably 2 to 6 parts by weight. If the amount is less than 0.1 parts by weight, the charge amount of the toner becomes insufficient,
Problems such as toner scattering and background contamination occur. When the amount exceeds 10 parts by weight, the electrostatic adhesion to the carrier becomes strong, which causes problems such as a decrease in the fluidity of the developer and a decrease in the amount of development. Further, to the colored toner after firing used in the present invention, conventionally known additives such as hydrophobic silica, zinc stearate, aluminum stearate, and titanium oxide may be added in order to improve the fluidity of the toner. it can.

As the carrier in the present invention, iron powder,
A conventionally known carrier such as ferrite and glass beads can be used, and the carrier may be coated with polyfluorocarbon, polyvinyl chloride, polyvinylidene chloride, a phenol resin, polyvinyl acetal, a silicon resin, or the like. The mixing ratio of the toner and the carrier is
About 1 to 30 parts by weight of the toner is suitable for part by weight, and 8 to 16 parts by weight is preferable.

In order to make the true specific gravity ratio between the carrier and the toner which is colored after firing become 2-3, for example, the following may be performed. That is, the true specific gravity of the toner is substantially determined by the specific gravity and the compounding ratio of the resin and the colorant in the toner. For example, the true specific gravity can take a large range of about 1.5 to 5 depending on the specific gravity and the content of the colorant. However, the true specific gravity of the carrier is in a small range of about 5.6 ± 1 (this is because when the resin coating layer of the carrier is increased, film shaving occurs, causing toner spent, and the resin coating layer becomes extremely large. Therefore, the true specific gravity of the toner may be adjusted according to the specific gravity and content of the colorant contained in the toner. A preferable specific method is, for example, a method in which the above-mentioned alloy pigment is used as a colorant and the weight ratio of the resin to the alloy pigment in the toner is about 3: 7.

An example of the image forming method of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a color electrophotographic copying apparatus, and FIG. 2 is a schematic cross-sectional view showing the periphery of a photoconductor and an intermediate transfer belt unit. In FIG. 1, a color image reading apparatus 1 converts an image of a document 3 into an illumination lamp 4, mirror groups 5 a, 5 b, 5 c and a lens 6.
An image is formed on the color sensor 7 through the CPU, and color image information of the original is read for each color separation light of, for example, blue (hereinafter, referred to as B), green (hereinafter, referred to as G), and red (hereinafter, referred to as R). Convert to image signal. And
Based on the B, G, and R color separation image signal intensity levels, an image processing unit (not shown) performs a color conversion process to obtain black (hereinafter, referred to as Bk), cyan (hereinafter, referred to as C), and magenta (hereinafter, referred to as C). (Hereinafter referred to as M) and yellow (hereinafter referred to as Y) color image data.

Based on the color image data, a full-color toner image is formed on the transfer sheet as follows. In the color image recording apparatus 2 shown in FIG. 1, the electrophotographic photosensitive member 9 rotates counterclockwise as indicated by an arrow, and around the photosensitive member cleaning unit (including a pre-cleaning static eliminator) 10, a static elimination lamp 11, A charger 12, a potential sensor 13, a black developing unit 14, a cyan developing unit 15, a magenta developing unit 16, a yellow developing unit 17, an optical sensor 18 for detecting a development density pattern, an intermediate transfer belt 19, and the like are arranged. Further, as shown in FIG. 2, each developing unit rotates a developing sleeve (14a, 15a, 16a, 1a, 1a,
7a) and a developing paddle (14b, 15b, 16b, 17b) that rotates to draw up and agitate the developer, and a toner concentration sensor (14c, 15c, 16c,
17c). Each developing unit includes a carrier and a toner that is colored after firing.
A developer having a true specific gravity ratio of the carrier and the toner of 2 to 3 is loaded.

The black image data is sent to the color image recording device 2, the writing optical unit 8 converts the black image data into an optical signal, and performs optical writing on the charged electrophotographic photosensitive member 9 by laser light. Then, an electrostatic latent image of a black image is formed on the electrophotographic photosensitive member 9 (for example, the image portion -80 V to -130 V, the non-image portion -5).
00V to -700V). The electrostatic latent image of this black image has a tip end of the electrostatic latent image which is a black developing unit 14.
Is developed by the black toner on the developing sleeve 14a that has started rotating before reaching the developing position, and a black toner image is formed on the electrophotographic photosensitive member 9.
When the rear end portion of the electrostatic latent image has passed the developing position, the developing unit 14 is evacuated to the inoperative state.

The black toner image formed on the electrophotographic photosensitive member 9 is transferred onto the surface of the intermediate transfer belt 19 driven at the same speed as the photosensitive member 9. The transfer of the toner image from the photoconductor 9 to the intermediate transfer belt is performed when the photoconductor 9 and the intermediate transfer belt 19 are in contact with each other.
This is performed by applying a predetermined bias voltage to.
After the black toner image is transferred to the intermediate transfer belt 19, the electrophotographic photosensitive member 9 is moved to the photosensitive member cleaning unit 1.
After being cleaned by 0, the charge is uniformly removed by the charge removing lamp 11 and then charged by the charger 12.

Next, the cyan image data is sent to the color image recording apparatus 2, the writing optical unit 8 converts the cyan image data into an optical signal, and performs optical writing on the charged electrophotographic photosensitive member 9 with a laser beam. Thereby, an electrostatic latent image of a cyan image is formed on the electrophotographic photosensitive member 9.
The electrostatic latent image of this cyan image is
The toner image is developed by the cyan developing unit 15 that operates in the same manner as in No. 4, and a cyan toner image is formed on the electrophotographic photosensitive member 9. The cyan toner image formed on the electrophotographic photosensitive member 9 is aligned with the black toner image already transferred to the intermediate transfer belt 19, and
Is transferred to the surface of

Thereafter, the magenta toner image and the yellow toner image are sequentially aligned and transferred onto the surface of the intermediate transfer belt 19 in the same manner.
A full-color toner image is formed thereon. The full-color toner image formed on the intermediate transfer belt 19 is transferred onto a transfer sheet by an intermediate transfer belt unit described below.

In FIG. 2, the intermediate transfer belt 19 is stretched around a drive roller 21, a transfer bias roller 20a, and a group of driven rollers, and is driven and controlled by a drive motor. As the intermediate transfer belt 19, for example, a carbon-dispersed fluorine resin ETFE (ethylene / tetrafluoro / ethylene, volume resistivity 10 ¹⁰ Ωcm, surface resistivity 10
⁹ Ωcm) can be used. Further, as the transfer bias roller 20a, for example, a hydrin rubber roller is coated with a PFE tube, and the volume resistivity is 10 ⁹ Ωc.
m can be used.

The belt cleaning unit 22 includes a brush roller 22a, a rubber blade 22b, a mechanism 22c for contacting and separating from the belt, and the like. While the toner image of each color is being transferred, the belt surface is moved by the contacting / separating mechanism 22c. Away from Then, the intermediate transfer belt 19
The toner images of the respective colors are accurately transferred to each other and transferred one after another, so that a full-color toner image is formed on the intermediate transfer belt 19. The transfer unit 23 for transferring the toner image from the intermediate transfer belt 19 to the transfer sheet includes a transfer bias roller 23a, a roller cleaning blade 23
b and a mechanism 23c for contacting and separating from the belt.

The bias roller 23a is normally connected to the belt 1
Although it is separated from the nine surfaces, when the full-color toner image formed on the intermediate transfer belt 19 is transferred to the transfer sheet, it is pressed by the contact / separation mechanism 23c at a certain timing, and a predetermined bias voltage is applied. Thereby, the full-color toner image formed on the intermediate transfer belt 19 is transferred to the transfer sheet.

Note that, as shown in FIG.
Is fed by the feed roller 25 and the registration roller 26 at the timing when the leading end of the full-color toner image formed on the intermediate transfer belt reaches the transfer position on the transfer sheet. The transfer sheet on which the full-color toner image is transferred is transported by the transport unit 27 to the fixing device 2.
8 and the fixing roller 28a controlled to a predetermined temperature.
Then, the full-color toner image is fixed by the pressure roller 28b. The surface of the intermediate transfer belt 19 after the transfer of the toner image onto the transfer sheet is cleaned by pressing the cleaning unit 22 with the contact / separation mechanism 22c.

In the above description, a case where a full-color toner image is obtained by four-color mode color image data of black, cyan, magenta, and yellow has been described.
Also in the three-color mode and the two-color mode, it is possible to form an electrostatic latent image based on a designated color, operate the developing unit for that color, and form a toner image on the transfer sheet in the same manner as described above. it can. When a single color toner image is to be formed on a transfer sheet, only the developing unit for that color is set in the operating state, and the intermediate transfer belt 19 is driven while being in contact with the surface of the electrophotographic photosensitive member 9 to further clean the image. The image forming operation can be performed while the unit 22 is still in contact with the intermediate transfer belt 19.

Next, a method for painting a heat-resistant solid surface using a transfer sheet having a toner image formed by the image forming method of the present invention will be described. When the transfer sheet having the toner image formed by the image forming method of the present invention is used as a transfer sheet for painting on a heat-resistant solid surface such as a ceramic product, a water-soluble layer is particularly preferable on the surface. It is preferable to form a toner image on the water-soluble layer of a transfer sheet having the following formula. The material of the water-soluble layer may be any water-soluble material, and for example, dextrin or polyvinyl alcohol can be used.

In order to paint a heat-resistant solid surface such as a porcelain product using a transfer sheet having a toner image formed by the image forming method of the present invention, for example, a transfer having a toner image on a water-soluble layer A solution of an acrylic resin, a polystyrene resin, a cellulosic resin, or the like is applied on the toner image of the sheet to form a resin film, and the transfer sheet is immersed in water to dissolve the water-soluble layer of the transfer sheet to form a toner image. Peel the retained resin film from the transfer sheet,
The resin film holding the toner image may be attached to the heat-resistant solid surface and then baked.

The method of baking on the surface of the heat-resistant solid is appropriately selected depending on whether it is baked in the vicinity of the surface of the heat-resistant solid or deeper from the surface. In any case, an electric furnace or a gas furnace is used. Can be done. When performing baking near the surface of the heat-resistant solid surface, the temperature is gradually increased from room temperature under a heating condition of about 200 ° C. for 1 hour, and the temperature is maintained at 750 ° C. to 850 ° C. for about 30 minutes to 1 hour. After that, the temperature is lowered to room temperature and taken out from the electric furnace or gas furnace, whereby the colorant in the toner is sintered on the heat-resistant solid surface with the glaze frit,
A heat-resistant solid product that is painted without white spots or uneven baking is obtained.

When it is desired to bake deep into the heat-resistant solid surface, the temperature is gradually increased from room temperature to 200 ° C. for about 1 hour, and the temperature is maintained at 1100 ° C. to 1300 ° C. for 30 minutes to 1 hour. Then, a method of lowering the temperature to room temperature is adopted. At this time, the heating start temperature is not limited to room temperature, but if a rapid temperature change is given during heating and cooling, depending on the heat-resistant solid, there is a slight difference depending on the thickness and the material of the heat-resistant solid. However, since cracks and shape changes may occur, the temperature change during baking is preferably 50 ° C / 1 hour to 500 ° C / 1 hour. If the temperature change at the time of temperature rise or cooling is made slower than 50 ° C./1 hour, the baking time will be delayed and the efficiency will be worsened. Further, if the temperature change at the time of heating or cooling is made faster than 500 ° C./1 hour, uneven baking or a change in shape of the heat-resistant solid may occur. Preferred conditions for the temperature rise or the cooling temperature change are 100 ° C./1 hour to 300 ° C./1 hour.

[0049]

The present invention will be described in more detail with reference to the following examples.

Example 1 First, using a glaze frit manufactured as follows,
Produce each colorant, using each colorant,
A developer containing a toner that was colored after firing was manufactured as described below. <Manufacture of glaze frit> Al ₂ O ₃ (80 g), SiO ₂
(370 g), Na ₂ O (50 g) and PbO (500 g)
g) was blended and pulverized with a stamp mill, mixed with a Henschel mixer, fired at 1200 ° C, and pulverized to produce a glaze frit.

<Production of Black Colorant> Cr ₂ O ₃ (11
0g), MnO (270 g), Fe ₂ O ₃ (112 g) and Co ₂ O ₃ (508 g) were mixed and pulverized with a stamp mill, and then mixed with a Henschel mixer.
It was baked at 0 ° C. and pulverized. After mixing 300 g thereof and 500 g of the above glaze frit with a Henschel mixer, 75 g
It was baked at 0 ° C. and pulverized to produce a black colorant (1) containing an alloy pigment.

<Production of Yellow Colorant> CuO (10
g), ZnO (190 g) and Sb ₂ O ₃ (800 g) were blended and pulverized by a stamp mill, then mixed by a Henschel mixer, and fired at 1100 ° C. to be pulverized. After mixing 300 g of the glaze frit and 500 g of the glaze frit with a Henschel mixer, the mixture was fired at 750 ° C. and pulverized to produce a yellow colorant containing an alloy pigment.

<Production of Magenta Colorant> Fe ₂ O ₃ (16
0g), NiO (40g), CuO (40g) and A
After mixing with u ₂ O (760 g) and pulverizing with a stamp mill, the mixture was mixed with a Henschel mixer, which was fired at 1100 ° C. and pulverized. 300 g of the glaze frit 5
After mixing 00 g with a Henschel mixer, the mixture was fired at 750 ° C. and pulverized to produce a magenta colorant containing an alloy pigment.

<Production of Cyan Colorant> Cr ₂ O ₃ (170
g), Fe ₂ O ₃ (10 g), Co ₂ O ₃ (690 g) and ZnO (130 g) were blended, pulverized by a stamp mill, and then mixed by a Henschel mixer.
And crushed. After mixing 300 g thereof and 500 g of the above glaze frit with a Henschel mixer, the mixture was mixed at 750 ° C.
And crushed to produce a cyan colorant containing an alloy pigment.

Using the above-mentioned coloring agent, a developer comprising a carrier and a colored toner after baking was manufactured as follows. <Production of Black Developer Containing Black Toner That Is Colored After Firing> Polyester Resin (Tg = 59 ° C.) 1
00 parts by weight and a zinc salicylate derivative (Bontron E8
4, Orient Chemical Co.) and 4 parts by weight of the black colorant (1) were mixed with 230 parts by weight using a mixer.
The mixture was melt-kneaded with two rolls. After rolling and cooling the kneaded material,
Pulverization and classification were performed to produce a black toner having a volume average particle size of 9.3 μm. Further, 0.5 g of hydrophobic silica (R972, manufactured by Nippon Aerogel Co., Ltd.) was added to the black toner.
wt% and stirred with a mixer to mix black toner (b
k) was obtained.

On the other hand, 100 parts by weight of a silicone resin solution (KR50, manufactured by Shin-Etsu Chemical Co., Ltd.) and carbon black (BP20
00, manufactured by Cabot Corporation) 3 parts by weight and toluene 100
Parts by weight were dispersed with a homomixer for 30 minutes to prepare a coating layer forming liquid, and the coating layer forming liquid and an average particle diameter of 70 μm
Using a fluidized bed type coating apparatus, a carrier having a coating layer formed on the surface of the spherical ferrite carrier was manufactured using 1000 parts by weight of the spherical ferrite carrier. Next, 90 g of the black toner (bk) and 910 g of the carrier are placed in a ball mill and stirred for 15 minutes to obtain a black developer (BK).
Was manufactured.

<Production of Yellow Developer Containing Yellow Toner That Is Colored After Firing> The above black developer (B
A yellow toner having a volume average particle diameter of 9.3 μm is manufactured using the yellow colorant in place of the black colorant (1) in the production of K), and the yellow toner is further added to a hydrophobic silica (R972, Nippon Aerogel Co., Ltd.). Was prepared in the same manner as in the preparation of the black developer (BK), except that 0.5 wt% of the yellow developer (Y) was added and the yellow toner (y) obtained by stirring with a mixer was used. did.

<Production of magenta developer containing magenta toner which is colored after firing> The above-mentioned black developer (B
A magenta toner having a volume average particle size of 9.1 μm was produced using the above-mentioned magenta colorant in place of the black colorant (1) in the production of K), and the magenta toner was further added to hydrophobic silica (R972, Nippon Aerogel Co., Ltd.). Magenta developer (M) was prepared in the same manner as in the preparation of the black developer (BK) except that magenta toner (m) obtained by adding 0.5 wt% of did.

<Production of Cyan Developer Containing Cyan Toner That Is Colored After Firing> Black Developer (BK)
A cyan toner having a volume average particle diameter of 9.0 μm was produced using the cyan colorant in place of the black colorant (1) in the production of the above. Further, a hydrophobic silica (R972, manufactured by Nippon Aerogel Co., Ltd.) was added to the cyan toner. 0.5 wt%
A cyan developer (C) was produced in the same manner as in the production of the black developer (BK), except that the cyan toner (c) obtained by adding and stirring with a mixer was used.

The true specific gravity ratio (carrier / toner) of the carrier and the toner in each developer was measured by the method described above. The results are shown in Table 1 below.

[0061]

[Table 1]

Next, the above-mentioned black developer (BK),
Each of 450 g of the yellow developer (Y), the magenta developer (M) and the cyan developer (C) is mounted on a developing unit of an electrophotographic color copying machine (Pretail 650, manufactured by Ricoh Co., Ltd.) and transferred under the following copying conditions. Sheet (SN1
00, a full-color toner image was formed on a ceramic transfer paper (OK series, manufactured by Nitto Paper Industries Co., Ltd.). In addition,
The temperature of the fixing roller at this time was set to 180 ° C.

[Copying conditions] Process speed: 180 mm / sec Charging potential: -650 V Exposure potential: -100 to -500 V Developing bias: -500 V Belt transfer bias: 1400 to 1700 V Transfer sheet transfer bias: 900 to 1500 V

A polystyrene resin liquid is applied to the upper surface of the toner image of the transfer sheet obtained as described above, and dried to form a resin film. The transfer sheet is placed in a water tank, and the toner held on the polystyrene resin film is The image is peeled off from the transfer sheet, and tiles (RS252 / 1001, IN
(Manufactured by AX Corporation) at a heating rate of 100 degrees / hour for 8 hours.
After the temperature was raised to 00 ° C., it was kept at 800 ° C. for 30 minutes, allowed to cool naturally, and the pattern was sintered on the tile. As a result, a high-density and clear sintered pattern without white spots was obtained on the tile.

Example 2 In Example 1, 100 parts by weight of the polyester resin was changed to 70 parts by weight, and 230 parts by weight of the black colorant (1), the yellow colorant, the magenta colorant, and the cyan colorant were replaced by 260 parts by weight. Except that the black toner (bk-1) and the yellow toner (y-
1), a magenta toner (m-1) and a cyan toner (c-1), and a black developer (BK- 1), a yellow developer (Y-1), a magenta developer (M-1) and a cyan developer (C-1). The true specific gravity ratio of carrier and toner (carrier / toner) in each developer was measured by the method described above. The results are shown in Table 2 below.

[0066]

[Table 2]

Next, the black developer (BK-
1), yellow developer (Y-1), magenta developer (M
1) and a full-color toner image is formed on a transfer sheet in the same manner as in Example 1 except that the cyan developer (C-1) is used. The pattern was sintered. As a result, a high-density and clear sintered pattern without white spots was obtained on the tile.

Example 3 In Example 1, 100 parts by weight of the polyester resin was changed to 130 parts by weight, and 230 parts by weight of the black colorant (1), the yellow colorant, the magenta colorant, and the cyan colorant were replaced by 200 parts by weight. In the same manner as in Example 1 except that
Black toner (bk-2), yellow toner (y-
2), a magenta toner (m-2) and a cyan toner (c-2), and the black developer (BK- 2), a yellow developer (Y-2), a magenta developer (M-2) and a cyan developer (C-2). The true specific gravity ratio of carrier and toner (carrier / toner) in each developer was measured by the method described above. The results are shown in Table 3 below.

[0069]

[Table 3]

Next, the above-mentioned black developer (BK-
2), yellow developer (Y-2), magenta developer (M
-2) and a full-color toner image was formed on a transfer sheet in the same manner as in Example 1 except that the cyan developer (C-2) was used. The pattern was sintered. As a result, a high-density and clear sintered pattern without white spots was obtained on the tile.

Example 4 In Example 1, 100 parts by weight of the polyester resin was changed to 165 parts by weight, and 230 parts by weight of the black colorant (1), yellow colorant, magenta colorant and cyan colorant were replaced by 165 parts by weight. In the same manner as in Example 1 except that
Black toner (bk-3), yellow toner (y-
3), a black developer (BK-3), a yellow developer (Y-3), and a magenta toner (m-3) and a cyan toner (c-3), except that they were produced.
Magenta developer (M-3) and cyan developer (C-
3) was manufactured. The true specific gravity ratio of carrier and toner (carrier / toner) in each developer was measured by the method described above. The results are shown in Table 4 below.

[0072]

[Table 4]

Next, the black developer (BK-
3), yellow developer (Y-3), magenta developer (M
-3) and a cyan developer (C-3), except that a full-color toner image was formed on a transfer sheet in the same manner as in Example 1, and the transfer sheet was used to form tile images in the same manner as in Example 1. The pattern was sintered. As a result, a high-density and clear sintered pattern without white spots was obtained on the tile.

Example 5 In Example 1, 100 parts by weight of the polyester resin was changed to 200 parts by weight, and 230 parts by weight of the black colorant (1), the yellow colorant, the magenta colorant, and the cyan colorant were changed to 130 parts by weight. In the same manner as in Example 1 except that
Black toner (bk-4), yellow toner (y-
4), a black developer (BK-4), a yellow developer (Y-4), and a magenta toner (m-4) and a cyan toner (c-4), except that they were produced.
Magenta developer (M-4) and cyan developer (C-
4) was manufactured. The true specific gravity ratio of carrier and toner (carrier / toner) in each developer was measured by the method described above. The results are shown in Table 5 below.

[0075]

[Table 5]

Next, the above-mentioned black developer (BK-
4), yellow developer (Y-4), magenta developer (M
-4) and a full-color toner image was formed on a transfer sheet in the same manner as in Example 1 except that the cyan developer (C-4) was used. The pattern was sintered. As a result, a clear sintered pattern without white spots was obtained on the tile, but the density was slightly lower.

Comparative Example 1 In Example 1, 100 parts by weight of the polyester resin was changed to 20 parts by weight, and 230 parts by weight of the black colorant (1), the yellow colorant, the magenta colorant, and the cyan colorant were replaced by 310 parts by weight. Except that the black toner (bk-5) and the yellow toner (y-
5), a black developer (BK-5), a yellow developer (Y-5), and a magenta toner (m-5), and a cyan toner (c-5), except that they were produced.
Magenta developer (M-5) and cyan developer (C-
5) was produced. The true specific gravity ratio of carrier and toner (carrier / toner) in each developer was measured by the method described above. The results are shown in Table 6 below.

[0078]

[Table 6]

Next, the black developer (BK-
5), yellow developer (Y-5), magenta developer (M
Except that -5) and cyan developer (C-5) were used, a full-color toner image was formed on the transfer sheet in the same manner as in Example 1, and the transfer sheet was used to form a tile on the tile in the same manner as in Example 1. The pattern was sintered. As a result, a small white drop of about 1 mm was generated in the sintered pattern on the tile.

Comparative Example 2 In Example 1, 100 parts by weight of the polyester resin was changed to 230 parts by weight, and 230 parts by weight of the black colorant (1), the yellow colorant, the magenta colorant, and the cyan colorant were changed to 100 parts by weight. In the same manner as in Example 1 except that
Black toner (bk-6), yellow toner (y-
6), a black developer (BK-6), a yellow developer (Y-6), and a magenta toner (m-6) and a cyan toner (c-6), except that they were produced.
Magenta developer (M-6) and cyan developer (C-
6) was manufactured. The true specific gravity ratio of carrier and toner (carrier / toner) in each developer was measured by the method described above. The results are shown in Table 7 below.

[0081]

[Table 7]

Next, the black developer (BK-
6), yellow developer (Y-6), magenta developer (M
-6) and a full-color toner image was formed on a transfer sheet in the same manner as in Example 1 except that the cyan developer (C-6) was used. The pattern was sintered. As a result, a white drop of about 3 mm was generated in the sintered pattern on the tile, and the pattern became a mat-like pattern in which the colorant was gathered.

Comparative Example 3 In Example 1, 100 parts by weight of the polyester resin was changed to 260 parts by weight, and 230 parts by weight of the black colorant (1), the yellow colorant, the magenta colorant, and the cyan colorant were changed to 70 parts by weight. Except that the black toner (bk-7) and the yellow toner (y-
7), a black developer (BK-7), a yellow developer (Y-7), and a magenta toner (m-7), and a cyan toner (c-7), except that they were produced.
Magenta developer (M-7) and cyan developer (C-
7) was manufactured. The true specific gravity ratio of carrier and toner (carrier / toner) in each developer was measured by the method described above. The results are shown in Table 8 below.

[0084]

[Table 8]

Next, the black developer (BK-
7), yellow developer (Y-7), magenta developer (M
-7) and a cyan developer (C-7), except that a full-color toner image was formed on a transfer sheet in the same manner as in Example 1, and the transfer sheet was used to form tile images in the same manner as in Example 1. The pattern was sintered. As a result, a white drop of about 3 mm was generated in the sintered pattern on the tile, and the pattern became a mat-like pattern in which the colorant was gathered.

Example 6 Cr ₂ O ₃ (110 g), MnO (270 g), Fe ₂ O ₃
(112 g) and Co ₂ O ₃ (508 g) were mixed and pulverized by a stamp mill, and then mixed and pulverized by a Henschel mixer. Manufactured. A black developer was manufactured in the same manner as in Example 1 except that the black colorant (2) was used instead of the black colorant (1). The true specific gravity ratio between the carrier and the toner in this black developer was 2.20. Next, in Example 1, the black developer (B
A full-color toner image is formed on a transfer sheet in the same manner as in Example 1 except that the above black developer is used in place of K), and a pattern is formed on a tile in the same manner as in Example 1 using the transfer sheet. Sintered. This sintered image was a good sintered image with no white spots, but the density of the black portion was low.

[0087]

According to the present invention, a toner image having few voids in a toner image layer can be formed on a transfer sheet. Using the transfer sheet, the toner image is transferred to a heat-resistant solid surface and adhered. By attaching and baking it,
It is possible to form a picture free from white spots and uneven printing on the heat-resistant solid surface.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a color electrophotographic copying apparatus.

FIG. 2 is a schematic cross-sectional view showing the periphery of a photoconductor and an intermediate transfer belt unit.

[Explanation of symbols]

 Reference Signs List 1 color image reading device 2 color image recording device 9 electrophotographic photoreceptor 14 black developing unit 15 cyan developing unit 16 magenta developing unit 17 yellow developing unit 19 intermediate transfer belt 24 transfer sheet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 15/16 G03G 9/08 391

Claims (7)

[Claims] 1. An electrostatic latent image on an image carrier is developed by a developer comprising a carrier and a color toner after baking, and
In an image forming method in which an obtained image is transferred from an image carrier to a transfer sheet to form a toner image on the transfer sheet, a true specific gravity ratio of carrier and toner (carrier / toner)
Is an image forming method. 2. The image forming method according to claim 1, wherein the toner image is transferred from the image carrier to a transfer sheet via an intermediate transfer belt. 3. The image forming method according to claim 1, wherein the transfer sheet is a transfer paper sheet for painting for painting on a heat-resistant solid surface. 4. The image forming method according to claim 3, wherein the transfer sheet has a water-soluble layer, and the toner image is transferred onto the water-soluble layer. 5. The image forming method according to claim 1, wherein the toner image is formed with at least one of four color toners of yellow, magenta, cyan, and black. 6. The image forming method according to claim 1, wherein the colored toner after firing contains an alloy pigment. 7. A developer comprising a carrier and a toner which is colored after firing, wherein the true specific gravity ratio (carrier / toner) of the carrier and the toner is 2-3.