JPH1195578A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a toner image without causing voids and printing unevenness in a pattern printed on the surface of a heat-resistant solid on a transfer sheet by limiting the range affected by an electric field generated by a transfer bias within the close contact range of an image carrier with the transfer sheet. SOLUTION: The toner image is transferred from a photoreceptor 9 to an intermediate transfer belt 19, in such a manner that a prescribed bias voltage is applied to a transfer bias roller 20a, in the close contact state of the photoreceptor 9 with the intermediate transfer belt 19. The close contact state of the photoreceptor 9 with the belt 19 is obtained in such a manner that the belt 19 is brought into press-contact with the photoreceptor 9 b the transfer bias roller 20a and a ground roller 20b. The belt 19 is grounded by the ground roller 20 b and the range affected by the electric field generated by the transfer bias applied by the transfer bias roller 20a can be limited within the close contact range of the photoreceptor 9 with the belt 19.

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 an intermediate transfer belt from an image carrier, and then transferring the toner image on the intermediate transfer belt to a transfer sheet to form a toner image on the transfer sheet More particularly, the present invention relates to an image forming method for forming a toner image with a colored toner after baking on a transfer sheet for painting for painting on a heat-resistant solid surface such as ceramic, glass, enamel, tile, and stone. Things.

[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.

In order to manufacture a large number of ceramic products having the same pattern, a pattern is formed on transfer paper by a screen printing method, and then the pattern is peeled off from the transfer paper and pasted on the ceramic product surface. It is common practice to burn it. This method is described in, for example,
As disclosed in Japanese Patent No. 407, an image is formed on a transfer paper having a water-soluble adhesive 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 the screen printing method, there are a plurality of steps for preparing a plate for forming an ink image for a picture, which requires enormous time and labor, not only lacks immediacy but also reduces the number of lots. However, there is a drawback in that a unit price per product is high when producing a wide variety of products. Further, since an organic solvent is used at the time of printing, there are disadvantages such as a poor working environment. As a method for solving such a problem 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 are contained on a transfer paper by using an electrophotographic method). For example, a method of forming an image for a pattern using a toner or the like, 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-7-199.
540, JP-A-7-2890, JP-A-7-228037, JP-A-7-300382, JP-A-8-104050, JP-A-8-114
No. 96, JP-A-8-119668 and the like. 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 the method is excellent in immediacy and can easily produce a product of a small lot and many kinds. Can be made.

[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.

[0006]

According to the present invention, first, an electrostatic latent image on an image carrier is developed with a color toner after baking, and an image carrier having a toner image and a transfer sheet are developed. In an image forming method in which a toner image is transferred to a transfer sheet by using a transfer bias, the range in which an electric field generated by the transfer bias affects the image carrier is in a range in which the image carrier and the transfer sheet are in close contact with each other. An image forming method is provided.

Second, the electrostatic latent image on the image carrier is developed with a color toner after baking, the image carrier having the toner image is brought into close contact with the intermediate transfer belt, and the toner image is intermediately transferred by a transfer bias. In an image forming method for transferring a toner image on an intermediate transfer belt to a transfer sheet to form a toner image on a transfer sheet, the range of influence of an electric field generated by a transfer bias is determined between the image carrier and the intermediate transfer belt. An image forming method is provided in which the transfer belt is in a range in which the transfer belt is in close contact with the transfer belt.

Thirdly, in the image forming method described in the second aspect, the image carrier and the intermediate transfer belt are in close contact with each other in a range where the electric field generated by the transfer bias is affected by grounding the intermediate transfer belt. There is provided an image forming method characterized by being within the range.

Fourthly, there is provided an image forming method according to the third aspect, wherein the intermediate transfer belt is grounded at a portion where the image carrier and the intermediate transfer belt start to come into close contact with each other. Is done.

Fifthly, there is provided an image forming method according to the second, third or fourth aspect, wherein the volume resistivity of the intermediate transfer belt is 10 ⁹ Ωcm or less.

Sixth, in the image forming method according to any one of the second to fifth aspects, a multicolor toner image is formed on an intermediate transfer belt, and the multicolor toner image is transferred to a transfer sheet. An image forming method is provided.

Seventh, in the image forming method according to any one of the first to sixth aspects, the toner image transferred onto the transfer sheet is fixed on the transfer sheet by heat and pressure. A method of forming is provided.

Eighth, there is provided an image forming method according to the seventh aspect, wherein the toner image transferred onto the transfer sheet is fixed by a fixing roller.

Hereinafter, the present invention will be described in more detail. When the toner image for the pattern formed on the transfer sheet by the electrophotographic method is peeled off together with the resin film formed thereon and pasted on a heat-resistant solid surface such as a ceramic product and baked, When the printing temperature was around 200 ° C. to 400 ° C., it was observed that white spots and uneven printing which did not occur in the case of the screen printing method occurred. As a result of examining the cause, the difference between the ink image on the transfer sheet formed by the screen printing method and the toner image on the transfer sheet formed by the electrophotographic method is that there is substantially no gap in the ink image On the other hand, 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 heat-resistant solid surface to have white voids and uneven printing. It is clear that will occur.

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 studying the cause of the formation of voids in the toner image layer formed of toner particles on the transfer sheet, the toner image layer on the transfer sheet is fixed by the action of heat and pressure of the fixing roller. As a result, the voids in the toner image layer are considerably reduced, but the electrostatic latent image on the image carrier is developed by electrophotography with a colored toner after firing, and the image carrier having the toner image and the transfer sheet are developed. When the toner image is transferred to the transfer sheet by the transfer bias, or when the image carrier having the toner image is brought into close contact with the intermediate transfer belt, and the toner image is transferred to the intermediate transfer belt by the transfer bias, the transfer bias is applied. The electric field generated on the image carrier acts on the toner image on the image carrier, increasing the distance between the toner particles and transferring to the transfer sheet or the intermediate transfer belt. The toner image transferred from the image carrier onto the transfer sheet, or the toner image transferred from the intermediate transfer belt onto the transfer sheet is fixed even after the toner image is fixed. It was found that voids remained in the layer.

As a result of intensive studies based on such knowledge, the present invention has been achieved. That is, according to the present invention, the electrostatic latent image on the image carrier is developed with a colored toner after firing, the image carrier having the toner image is brought into close contact with the transfer sheet, and the toner image is transferred by the transfer bias. In the image forming method, the range of the influence of the electric field generated by the transfer bias is set within a range in which the image carrier and the transfer sheet are in close contact with each other, or the image carrier having the toner image and the intermediate transfer belt are Adhere
In an image forming method in which a toner image is transferred to an intermediate transfer belt by a transfer bias and then the toner image on the intermediate transfer belt is transferred to a transfer sheet to form a toner image on the transfer sheet, the influence of an electric field generated by the transfer bias is reduced. By setting the range to be within the range in which the image carrier and the intermediate transfer belt are in close contact with each other, it is possible to prevent an increase in the interval between toner particles due to the effect of the electric field generated by the transfer bias, and thereby the transfer sheet When the toner image is fixed, the voids in the toner image layer 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.

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 forms an image of an original 3 on a color sensor 7 via an illumination lamp 4, a mirror group 5abc and a lens 6, and converts color image information of the original into, for example, blue (hereinafter referred to as B). ), Green (G
) And red (hereinafter referred to as R) color-separated light, and converted into an electrical image signal. And this B,
Based on the 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 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 is loaded with an electrophotographic developer containing a toner that is colored after firing.

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 to the intermediate transfer belt 1 driven at a constant speed by the intermediate transfer belt unit described below.
9 is transferred to the surface. 2, the intermediate transfer belt 19 includes a driving roller 21 and a transfer bias roller 20.
a, it is stretched around the ground roller 20b and the driven roller group, and is driven and controlled by a drive motor.

As the intermediate transfer belt 19, for example, carbon-dispersed fluorine resin ETFE (ethylene / tetrafluoro / ethylene) or the like can be used, and a belt having a volume resistivity of 10 ⁹ Ωcm or less is preferable. As the transfer bias roller 20a, for example, P
A FE tube coated with a volume resistivity of 10 ⁹ Ωcm or the like can be used. In addition, earth roller 2
As 0b, for example, one grounded in a roller shaft or the like can be used.

The transfer of the toner image from the photosensitive member 9 to the intermediate transfer belt 19 is performed by applying a predetermined bias voltage to the transfer bias roller 20a in the state of close contact between the photosensitive member 9 and the intermediate transfer belt 19. . The close contact between the photoconductor 9 and the intermediate transfer belt 19 is performed by pressing the intermediate transfer belt 19 against the photoconductor 9 by the transfer bias roller 20a and the ground roller 20b.

The intermediate transfer belt 19 has a ground roller 20b.
, So that the range of influence of the electric field generated by the transfer bias applied by the transfer bias roller 20a is limited to the photosensitive member 9 and the intermediate transfer belt 1.
9 can be set in the range where it is in close contact. This prevents the electric field from acting on the toner image on the photoreceptor before the intermediate transfer belt 19 comes into close contact, prevents an increase in the gap between toner particles due to the transfer bias electric field, and reduces the gap in the toner image. Generation can be prevented.

The black toner image is transferred to the intermediate transfer belt 19.
After the transfer, the electrophotographic photoreceptor 9 is cleaned by the photoreceptor cleaning unit 10 and the charge removing lamp 1 is removed.
After the charge is uniformly removed by 1, the charge is given by the charger 12. Next, the cyan image data is sent to the color image recording device 2, the writing optical unit 8 converts the cyan image data into an optical signal, and performs optical writing with a laser beam on the charged electrophotographic photosensitive member 9, thereby obtaining an electronic image. An electrostatic latent image of a cyan image is formed on the photoconductor 9.

The electrostatic latent image of the cyan image is supplied to the cyan developing unit 1 which operates in the same manner as the black developing unit 14.
5 to form a cyan toner image on the electrophotographic photoreceptor 9. The cyan toner image formed on the electrophotographic photosensitive member 9 is aligned with the black toner image already transferred on the intermediate transfer belt 19, and is transferred onto the surface of the intermediate transfer belt 19 in the same manner as in the case of the black toner image. You. Thereafter, similarly, the magenta toner image and the yellow toner image are sequentially aligned and transferred to the surface of the intermediate transfer belt 19, whereby a full-color toner image is formed on the intermediate transfer belt 19.

The full-color toner image formed on the intermediate transfer belt 19 is transferred onto a transfer sheet as follows. In FIG. 2, a transfer unit 23 that transfers a toner image from the intermediate transfer belt 19 to a transfer sheet includes a transfer bias roller 23a, a roller cleaning blade 23b, and a mechanism 23c for contacting and separating from the belt. The bias roller 23a normally has a belt 19
Although it is separated from the surface, when the full-color toner image formed on the intermediate transfer belt 19 is transferred to the transfer sheet, the full-color toner image is pressed by the contact / separation mechanism 23c in a timely manner, 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.

Incidentally, 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 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 each color toner image is being transferred onto the intermediate transfer belt 19, the toner image is separated from the belt surface by the contact / separation mechanism 22 c, and after the toner image is transferred from the intermediate transfer belt 19 to the transfer sheet, the intermediate transfer belt 19 The surface of the cleaning unit 22 is cleaned by pressing the cleaning unit 22 by the contact / separation mechanism 22c.

As shown in FIG. 1, the transfer sheet on which the full-color toner image has been transferred is conveyed to a fixing device 28 by a conveyance unit 27, and the fixing roller 2 is controlled to a predetermined temperature.
8a and the pressure roller 28b fix a full-color toner image. In the fixing step, it is preferable to use a fixing method using a fixing roller for fixing by supplying heat and simultaneously applying heat. The temperature of the fixing roller is 160 ° C.
It is preferable that the temperature is set to 190 ° C. Further, a method of applying a release agent such as silicone oil to the fixing roller to prevent fusion of the toner to the fixing roller is also effective. If the set temperature of the fixing roller is lower than 160 ° C., the softening of the toner is not performed smoothly, and a gap remains. If the temperature is set higher than 190 ° C., the heat supply of the fixing roller may not follow in continuous copying. The preferable temperature of the fixing roller is 170 ° C. to 185 ° C., although it depends on the process speed. With this temperature setting, a stable toner image of stable quality can be obtained because there is little variation in the fixing roller temperature in continuous copying.

In the above description, the 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, 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 1 of the periodic table.
Group 2 Cd, Group 4 Ti, Group 5 V, Sb, Group 6 S
e, Cr, Mo, W, U, Group 7 Mn, Group 8 Fe, C
It contains a coloring agent such as a pigment for ceramics and a thermoplastic resin using an oxide of an element such as o, Ni, Ir, Pt or the like alone or blended (mixed).

Conventional ceramic pigments generally have a low absorption coefficient of the pigment itself. To form a full-color image having a high image density using a toner containing these ceramic pigments as a coloring agent, a large amount of toner adherence is required. It is necessary to. As the colorant in the toner that is colored after firing, a plurality of the above metals or oxides thereof are blended (mixed).
Then, this is heated to 1000 ° C. to 1200 ° C. and melted,
Alloy pigments that have been alloyed with a plurality of metals are particularly preferred.

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 the alloying of multiple metals is that the d orbital of the metal element that was heavy when it was a single metal split due to the effect of the composite metal, increasing the number of orbitals that can make electron transition. It is presumed that this is because the apparent oscillator strength increases.

As the thermoplastic resin, binder resins used in conventionally known toners can be used, and examples thereof include polyester, polystyrene, polyethylene, polyamide, epoxy, epoxy polyol, and terpene resins. 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, for the toner which is colored after firing,
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 colorant, a clear full-color image having a high image density and a small amount of toner adherence can be formed on a transfer sheet, and the toner image can be formed on a heat-resistant solid surface such as a ceramic product. By transferring the image to the surface and printing it, a clear image with high image density can be formed 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 on the heat-resistant solid surface. When it is cooled, the colorant 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, shelf Sand, ammonium metavanadate, metal oxides such as tungsten oxide and vanadium pentoxide, tin oxide, zirconium oxide, cerium oxide, molybdenum oxide, metal fluorides such as calcium fluoride and aluminum fluoride, and glasslets as basic materials , Or a mixture thereof.

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.

Further, the toner which is colored after firing may contain a charge control agent, if necessary. As such a charge control agent, all conventionally known ones can be used,
For example, nigrosine dyes, quaternary ammonium salts, Cr-containing dyes, Zn-containing dyes, Fe-containing dyes, molybdic acid chelate dyes, fluorine-modified quaternary ammonium salts, and the like are appropriately selected and used according to the charging polarity.

The amount of the charge control agent used depends on the type of the thermoplastic resin, the presence or absence of additives used as necessary, and the toner production method 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. In addition, conventionally known additives such as hydrophobic silica, zinc stearate, aluminum stearate, and titanium oxide may be added as needed to improve the fluidity of the toner.

The toner which is colored after baking can be used as a so-called one-component developer for developing an electrostatic latent image as a developer of the toner alone, or a two-component developer obtained by mixing a toner and a carrier. It can be used as an agent. As a carrier when used as a two-component developer, a conventionally known carrier such as iron powder, ferrite, and glass beads can be used.
It may be coated with polyvinyl chloride, polyvinylidene chloride, phenol resin, polyvinyl acetal, silicone resin, or the like. The mixing ratio of the toner and the carrier is appropriately about 1 to 30 parts by weight, preferably 8 to 16 parts by weight, per 100 parts by weight of the carrier.

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. As a material for the water-soluble layer, any material may be used, such as dextrin or polyvinyl alcohol.

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 is performed. 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 is adhered to the heat-resistant solid surface, and the toner image side is adhered to the heat-resistant solid surface, and attached.
Just burn it.

The method of baking on the heat-resistant solid surface is appropriately selected depending on whether baking is performed near the surface of the heat-resistant solid or baking deeper from the surface. In each 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 perform baking deep inside the surface of the heat-resistant solid, the temperature is gradually increased from room temperature to 200 ° C. for 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.

[0046]

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

Example 1 First, using a glaze frit manufactured as described below,
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 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 containing a toner which is colored after firing was manufactured as follows. <Production of Black Developer Containing Colored Black Toner After Firing> Epoxy Resin (Tg = 60 ° C.) 100
4 parts by weight of a zinc salicylate derivative (Bontron E84, manufactured by Orient Chemical Co., Ltd.) and 230 parts by weight of the black colorant were mixed by a mixer, and then melt-kneaded with two rolls. The kneaded product was rolled and cooled, and then pulverized and classified to produce a black toner having a volume average particle diameter of 9.3 μm. Further, hydrophobic silica (R
972, manufactured by Nippon Aerogel Co., Ltd.) and stirred with a mixer to obtain a black toner (a).

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 solution, and the coating layer forming solution and an average particle diameter of 70 μm were prepared.
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 1,000 parts by weight of the spherical ferrite carrier of m. Next, 90 g of the black toner (a) and 910 g of the carrier were placed in a ball mill and stirred for 30 minutes to produce a black developer.

<Production of Yellow Developer Containing Colored Yellow Toner After Firing> A yellow toner having a volume average particle diameter of 9.3 μm was prepared by using the yellow colorant instead of the black colorant in the above black developer production. And a yellow developer was produced in the same manner as in the production of the black developer, except that the yellow toner was used.

<Production of magenta developer containing magenta toner that is colored after firing> A magenta toner having a volume average particle diameter of 9.1 μm using the above-mentioned magenta colorant instead of the black colorant in the production of the above-mentioned black developer. And a magenta developer was produced in the same manner as in the production of the black developer, except that the magenta toner was used.

<Production of Cyan Developer Containing Colored Cyan Toner After Firing> A cyan toner having a volume average particle diameter of 9.0 μm using the cyan colorant instead of the black colorant in the above black developer production. And a cyan developer was produced in the same manner as in the production of the black developer, except that the cyan toner was used.

Next, using the black developer, yellow developer, magenta developer and cyan developer produced as described above, a color electrophotographic copying machine described with reference to the schematic sectional views shown in FIGS. Under the following copying conditions, a full-color image was formed on a transfer sheet (SN100, transfer paper for ceramics manufactured by Nitto Paper Industries: OK series) to obtain a transfer sheet having a toner image. The temperature of the fixing roller was set at 180 ° C. [Copying conditions] Process speed: 180 mm / sec Charging potential: -650 V Exposure potential: -100 to -500 V Development bias: -500 V Belt transfer bias: 1400 to 1700 V Transfer sheet transfer bias: 900 to 1500 V

A polystyrene resin solution 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 Peel the image from the transfer sheet, make the toner image side adhere to the tile,
Affixed to a tile (RS252 / 1001, manufactured by INAX), heated to 800 ° C at a heating rate of 100 ° C / 1 hour, kept at 800 ° C for 30 minutes, allowed to cool naturally, and sintered the pattern on the tile I let it. As a result, a high-density and clear sintered pattern without white spots was obtained on the tile.

[0059]

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 attached to a heat-resistant solid surface, By baking it, it is possible to form a clear pattern with no 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 20a transfer bias roller 20b ground roller 21 drive roller 24 transfer sheet

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 15/01 114 G03G 15/20 101 15/20 101 9/08 361

Claims (8)

[Claims] An electrostatic latent image on an image carrier is developed with a color toner after baking, the image carrier having a toner image is brought into close contact with a transfer sheet, and the toner image is transferred to the transfer sheet by a transfer bias. An image forming method, wherein the range affected by an electric field generated by a transfer bias is within a range in which an image carrier and a transfer sheet are in close contact with each other. 2. An electrostatic latent image on an image carrier is developed with a color toner after baking, and an image carrier having a toner image is brought into close contact with an intermediate transfer belt, and a toner image is transferred to the intermediate transfer belt by a transfer bias. In an image forming method for transferring and then transferring a toner image on an intermediate transfer belt to a transfer sheet to form a toner image on the transfer sheet, a range affected by an electric field generated by a transfer bias is determined by an image carrier and an intermediate transfer belt. An image forming method, wherein the temperature is within a range in which the images are in close contact with each other. 3. An image forming apparatus according to claim 2, wherein the ground is applied to the intermediate transfer belt so that the range of the influence of the electric field generated by the transfer bias is within a range in which the image carrier and the intermediate transfer belt are in close contact with each other. Image forming method. 4. The image forming method according to claim 3, wherein the intermediate transfer belt is grounded at a portion where the image carrier and the intermediate transfer belt start to come into close contact with each other. 5. The intermediate transfer belt has a volume resistivity of 10 ⁹ Ω.
The image forming method according to claim 2, 3 or 4, wherein the size is less than or equal to cm. 6. The image forming method according to claim 2, wherein a multicolor toner image is formed on the intermediate transfer belt, and the multicolor toner image is transferred to a transfer sheet. 7. The image forming method according to claim 1, wherein the toner image transferred onto the transfer sheet is fixed on the transfer sheet by heat and pressure. 8. The image forming method according to claim 7, wherein the toner image transferred onto the transfer sheet is fixed by a fixing roller.