JP7728522B2 - Image forming method - Google Patents

Description

The present invention relates to an image forming method.

In the electrophotographic method, an electrostatic latent image is developed with a developer to form a visible image. The image is first formed on an electrostatic latent image carrier (also called a photoreceptor) containing a photoconductive material, and then developed with a developer containing toner to form a toner image. The toner image is then transferred to a transfer material such as paper, and fixed by applying heat and pressure to form a fixed image.

To form a full-color image by electrophotography, a toner set consisting of a combination of cyan toner, magenta toner, yellow toner, and black toner, which are called process colors, is generally used.
In recent years, as electrophotographic color image forming apparatuses have become more widespread, the applications of printed materials have expanded to a wide variety of fields. Particularly in the field of custom-made consumer goods, there is a growing need for electrophotographic printing on materials that cannot be printed (fixed) with conventional electrophotographic toners intended for printing on paper media. Specifically, there is a growing need for printing on fabric media such as sports team uniforms, shoes, and bags.

Patent document 1 describes an image formation method in which a first developer image is formed on a transfer medium using a color developer, then a second developer image is formed on the first developer image using a white developer, and this is then thermally transferred to fabric.

Printed images on fabric media must be able to adhere to uneven fabric fibers and have strong adhesion that will not peel off during washing. Furthermore, when printing on fabrics of various colors, particularly dark fabrics, the image must be able to conceal the color of the dark fabric and not impair the color of the image. In order to achieve the ideal state that overcomes these challenges, the selection of the image formation method is extremely important. A practical, simple method for forming images on fabric that overcomes these challenges has not yet been proposed, and no method suitable for practical use has yet been provided.

The present invention aims to solve the above-mentioned problems in the prior art and to achieve the following objects.
That is, an object of the present invention is to provide an image forming method that can be fixed to a fabric medium, has sufficient washing resistance, and can form an image with sufficient saturation even on a dark-colored fabric medium, which cannot be achieved by conventional image forming methods.

The present invention relates to an image forming method as described below.
An image forming method comprising the following steps 1 to 4, characterized in that in the following step 3, an image on a transfer medium is transferred and fixed onto an image receiving substrate at a temperature P _T [°C] that satisfies the following relational expression (1):
Step 1: A step of forming a toner image on a transfer medium using an electrophotographic image forming apparatus with an image forming toner; Step 2: A step of forming an undercoat layer on the toner image using an undercoat layer forming toner; Step 3: A step of combining an image receiving substrate and the undercoat layer and heating and pressing them together to transfer and fix the image on the transfer medium onto the image receiving substrate; Step 4: A step of separating the image transferred and fixed on the image receiving substrate from the transfer medium.
(In formula (1), UT _fb [° C.] is the flow-out start temperature of the toner forming the undercoat layer, and UT _1/2 [° C.] is the half-flow-out temperature of the toner forming the undercoat layer.)

The present invention can fix images to fabric media that cannot be achieved with conventional image formation methods, has sufficient washing durability, and provides images with sufficient saturation even on dark-colored fabrics.

FIG. 1 is a diagram showing stroke displacement in flow tester measurement.

(Image forming method)
The image forming method of the present invention is a method for transferring and fixing an image on a transfer medium onto an image receiving substrate, comprising a series of steps 1 to 4 below.
Step 1: A step of forming a toner image on a transfer medium using an electrophotographic image forming apparatus with an image forming toner; Step 2: A step of forming an undercoat layer on the toner image using an undercoat layer forming toner; Step 3: A step of combining an image receiving substrate and the undercoat layer and heating and pressing them together to transfer and fix the image on the transfer medium onto the image receiving substrate; Step 4: A step of separating the image transferred and fixed on the image receiving substrate from the transfer medium.

(Electrophotographic image forming apparatus)
The electrophotographic image forming apparatus may be any apparatus capable of printing process color toners and undercoat toners onto a transfer medium, such as a RICOH Pro C7200S printer manufactured by Ricoh Co., Ltd., which has been modified to allow the undercoat toner and image-forming toner to be set in one of the color stations.

(Regarding the image receiving substrate)
As the image receiving substrate in the present invention, general fabrics made of artificial or natural fibers such as cotton, polyester, silk, etc. can be used.

(Regarding transfer media)
As the transfer medium, for example, transfer paper or release paper that has been surface-treated to have appropriate fixing and releasability suitable for the image formation process can be used, such as WOW Light 8.0, WOW i Sheet 7A, WOW m Sheet 7 from Piotek Corporation, and CLAPp-MULT from Europort Co., Ltd.

(Regarding the heating and pressing means)
The heating and pressing means may be any means capable of applying the temperature and pressure necessary for fixing the toner to the image receiving substrate, and examples thereof include Model HTP234PS1, Model 728, and Model 201 manufactured by Piotec Corporation, and Hercules PH-4634, Hercules Wide PH-5040, Gaia PGA-5040, and Zeus PZ-130110D manufactured by Europort Co., Ltd. An iron may also be used as the heating and pressing means.

(Regarding fixing temperature)
From the viewpoint that the toner for forming the undercoat layer does not penetrate too deep into the image receiving substrate and remains on the surface, and exhibits good hiding power and adhesiveness, the transfer-fixing temperature is preferably a temperature P _T [°C] that satisfies the following relational expression (1):

(In formula (1), UT _fb [° C.] is the flow-out start temperature of the toner forming the undercoat layer, and UT _1/2 [° C.] is the half-flow-out temperature of the toner forming the undercoat layer.)

Furthermore, it is more preferable that the transfer-fixing temperature P _T [° C.] satisfies the following relational expression (2).

It is also preferable that the half outflow temperature CT _1/2 [° C.] of the image forming toner and the half outflow temperature UT _1/2 [° C.] of the undercoat layer forming toner satisfy the following relational expression (3).

(Method for measuring outflow start temperature and half outflow temperature)
The outflow start temperature and half outflow temperature are measured as follows:
Using a flow tester (Shimadzu Corporation, CFT-500D), 1.0 g of sample was heated at a temperature increase rate of 6°C/min, while a load of 1.96 MPa was applied by the plunger, and the sample was extruded from a nozzle 1.0 mm in diameter and 1.0 mm in length, to obtain a plot of the plunger depression of the flow tester versus temperature, as shown in Figure 1. In the plunger depression vs. temperature curve shown in Figure 1, the temperature at the inflection point where the plunger depression moves from a stable region of zero to an increasing region is defined as the outflow start temperature (UT _fb ), and the temperature at which half of the sample has flowed out is defined as the half outflow temperature (UT _1/2 ).

(Regarding fixing pressure and nip time)
There is no particular restriction on the heating and pressing time during transfer and fixation, but it is preferable to adjust the pressure to 100 g/cm ² to 800 g/cm ² and the time to 5 to 60 seconds depending on the thermal conductivity, thickness and surface roughness of the image-receiving substrate.

(Image forming toner)
As the toner for image formation, a process color toner used in an electrophotographic image forming apparatus can be used.

(Regarding the toner for forming the undercoat layer)
The toner for forming the undercoat layer can be one that uses the same constituent materials as the process color toner, and any color may be used, but preferably a transparent toner that does not contain a pigment or a white toner that uses a white pigment as a pigment is used. In particular, using a white toner is most preferable from the viewpoint of concealing the color of a dark-colored image-receiving substrate such as black or navy blue, and not impairing the color of the process color.

From the viewpoint of ensuring good adhesion of the undercoat layer-forming toner to the process color toner and preventing color mixing of the undercoat layer-forming toner and the process color toner, it is preferred that the half-flow temperature of the undercoat layer-forming toner be higher than the half-flow temperature of the process color toner.
Next, the materials constituting the toner will be described.

<About binder resin>
In the present invention, the binder resin (fixing resin) used as a toner material can be any conventionally known resin. Examples include styrene-based resins (homopolymers or copolymers containing styrene or styrene substitutes) such as styrene, poly-α-styrenestyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-methyl chloroacrylate copolymer, and styrene-acrylonitrile-acrylate copolymer; epoxy resins, vinyl chloride resins, rosin-modified maleic acid resins, phenolic resins, polyethylene resins, polypropylene resins, petroleum resins, polyurethane resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins, and polyvinyl butyrate resins. Furthermore, the method for producing these resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used.

In the present invention, it is preferable that the binder resin (fixing resin) contains a polyester resin, and it is particularly preferable that the binder resin be polyester resin as the main component. Compared to other resins, polyester resins generally allow for low-temperature fixing while maintaining heat-resistant storage stability, making them a suitable binder resin for the present invention.

The polyester resin used in the present invention is obtained by polycondensation of an alcohol and a carboxylic acid.
Examples of the alcohol to be used include glycols such as ethylene glycol, diene glycol, triethylene glycol, and propylene glycol; etherified bisphenols such as 1,4-bis(hydroxymeta)cyclohexane and bisphenol A; other dihydric alcohol monomers; and trihydric or higher polyhydric alcohol monomers.

Furthermore, examples of carboxylic acids include divalent organic acid monomers such as maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and malonic acid, and trivalent or higher polyvalent carboxylic acid monomers such as 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, and 1,2,7,8-octanetetracarboxylic acid.

(About wax)
In the toner of the present invention, there is no particular limitation on the type of wax, and it can be appropriately selected depending on the purpose, and one type may be used alone, or two or more types may be used in combination. Usable release agents include liquid paraffin, microcrystalline wax, natural paraffin, synthetic paraffin, polyolefin wax, and partial oxides thereof, or aliphatic hydrocarbons such as fluorides and chlorides thereof, animal oils such as beef tallow and fish oil, vegetable oils such as coconut oil, soybean oil, rapeseed oil, rice bran wax, and carnauba wax, higher aliphatic alcohols and higher fatty acids such as montan wax, fatty acid amides, fatty acid bisamides, metal soaps such as zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, zinc oleate, zinc palmitate, magnesium palmitate, zinc myristate, zinc laurate, and zinc behenate, fatty acid esters, and polyvinylidene fluoride.

(About pigments)
The colorant used in the toner of the present invention is not particularly limited, and any commonly used colorant can be appropriately selected and used.

For black toner, carbon black alone or a mixture of carbon black as the main component and copper phthalocyanine or the like, with the hue and brightness adjusted, is preferred.

For cyan toner, copper phthalocyanine pigment blue 15:3 or a mixture of the above colorant with aluminum phthalocyanine is preferred.

Magenta toners include Pigment Red 53:1, Pigment Red 81, Pigment Red 122, and Pigment Red 269, used alone or in combination.

As yellow toner, Pigment Yellow 74, Pigment Yellow 155, Pigment Yellow 180, and Pigment Yellow 185 can be used alone or in combination, but it is preferable to use Pigment Yellow 185 alone or in combination with Pigment Yellow 74 in terms of saturation and storage stability.

As the white pigment, titanium dioxide that has been surface-treated with silicon, zirconia, aluminum, polyol, or the like can be used.
As the green toner, Pigment Green 7 or the like can be used, but safety considerations must be taken into account.
Examples of blue toners include Pigment Blue 15:1 and Pigment Violet 23.

<Charge control agents>
The electrophotographic toner of the present invention may contain a charge control agent.
Examples of charge control agents include nigrosine and modified fatty acid metal salts, onium salts such as phosphonium salts and their lake pigments, triphenylmethane dyes and their lake pigments, metal salts of higher fatty acids, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, and dicyclohexyltin oxide, diorganotinborates such as dibutyltin borate, dioctyltin borate, and dicyclohexyltin borate, organometallic complexes, chelate compounds, monoazometal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, metal complexes of aromatic dicarboxylic acids, and quaternary ammonium salts. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol. These may be used alone or in combination.

(Externally added inorganic fine particles)
Examples of inorganic fine particles for external addition used in the present invention include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride, with silica, alumina, and titanium oxide being particularly preferred.
In addition, inorganic fine particles may be surface-treated with a hydrophobic treatment agent. Preferred examples of the hydrophobic treatment agent include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, and aluminum coupling agents. Furthermore, sufficient effects can be obtained by using silicone oil as a hydrophobic treatment agent.
Next, the developer will be described.

<About two-component developers>
The electrophotographic toner according to the present invention can be used in either one-component development method in which the toner is used as a developer, or two-component development method in which the toner is mixed with a carrier and used as a two-component developer.

When a two-component developer system is used, the magnetic fine particles used in the magnetic carrier may be magnetite, spinel ferrite such as gamma iron oxide, spinel ferrite containing one or more metals other than iron (Mn, Ni, Zn, Mg, Cu, etc.), magnetoplumbite ferrite such as barium ferrite, or particles of iron or alloys having an oxide layer on the surface.
The shape may be any of granular, spherical, and needle-like.

In particular, when high magnetization is required, it is preferable to use ferromagnetic fine particles such as iron.
In addition, in consideration of chemical stability, it is preferable to use magnetite, spinel ferrite containing gamma iron oxide, or magnetoplumbite ferrite such as barium ferrite.
By selecting the type and content of ferromagnetic fine particles, a resin carrier having a desired magnetization can be used.
In this case, the magnetic properties of the carrier are preferably such that the magnetization strength at 1,000 oersted is 30 to 150 emu/g.

Such resin carriers can be produced by spraying a molten mixture of magnetic fine particles and an insulating binder resin using a spray dryer, or by reacting and curing a monomer or prepolymer in an aqueous medium in the presence of magnetic fine particles to produce a resin carrier in which magnetic fine particles are dispersed in a condensation binder.

The chargeability can be controlled by adhering positively or negatively chargeable particles or conductive particles to the surface of the magnetic carrier, or by coating the surface with a resin.
Examples of surface coating materials (resins) that can be used include silicone resins, acrylic resins, epoxy resins, and fluorine-based resins. Positively or negatively charged particles or conductive particles can also be included in the coating, but silicone resins and acrylic resins are preferred.

<About the toner manufacturing method>
To prepare the toner of the present invention, first, a binder resin, a colorant, a release agent, and optionally a charge control agent are combined and thoroughly mixed in a mixer such as a Henschel mixer or a super mixer.
Next, the materials are melted and kneaded using a heat melt kneader such as a heating roll, a kneader, or an extruder to thoroughly mix them, and then cooled and solidified, followed by fine pulverization and classification to obtain a toner.
The pulverization method used in this case includes a jet mill method in which the toner is contained in a high-speed airflow and collided with a collision plate to be pulverized by the energy generated, an inter-particle collision method in which toner particles collide with each other in an airflow, and a mechanical pulverization method in which the toner is supplied between a narrow gap and a rotor rotating at high speed and pulverized.

Alternatively, a solution suspension method can be used to produce toner base particles by dissolving or dispersing toner materials in an organic solvent phase, dispersing the resulting oil phase in an aqueous medium phase, and then reacting the resin. After that, the solvent is removed, and the mixture is filtered, washed, and dried.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these. Furthermore, in the following description, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass."

(Toner Production)
[Production of White Toner 1]
The following components were used as toner raw materials.
Polyester resin RN-290 (manufactured by Kao Corporation) 94.7 parts Carnauba wax WA-05 (manufactured by Cerarica NODA Co., Ltd.) 5.3 parts Zirconium salicylate CCA TN-105 (manufactured by Hodogaya Chemical Co., Ltd.) 0.5 parts
Titanium oxide white pigment PF-739 (manufactured by Ishihara Sangyo Kaisha) 60.0 parts

The above toner raw materials were premixed using a Henschel mixer (FM20B, manufactured by Nippon Coke & Engineering Co., Ltd.) and then melted and kneaded at temperatures between 100°C and 130°C in a single-screw kneader (Ko-Kneader, manufactured by Buss). The resulting kneaded mixture was cooled to room temperature and coarsely pulverized to 200µm and 300µm using a Rotoplex. Next, the mixture was finely pulverized using a counter jet mill (100AFG, manufactured by Hosokawa Micron Corporation) while adjusting the pulverization air pressure appropriately to achieve the desired number-average particle size distribution. The particles were then classified using an air classifier (EJ-LABO, manufactured by Matsubo Corporation) while adjusting the louver opening appropriately to achieve the desired number-average particle size distribution, yielding toner base particles. Next, 3.0 parts of an external additive (hydrophobized silica HDK-2000, manufactured by Clariant) were added to 100 parts of the toner base particles and stirred and mixed using a Henschel mixer to produce [White Toner 1].

[Production of White Toner 2]
[White Toner 2] was prepared in the same manner as [White Toner 1] except that the following toner raw materials were used.
Polyester resin RN-290 (manufactured by Kao Corporation) 94.7 parts Carnauba wax WA-05 (manufactured by Cerarica NODA Co., Ltd.) 5.3 parts Zirconium salicylate CCA TN-105 1.0 part (manufactured by Hodogaya Chemical Co., Ltd.)
Titanium oxide white pigment PF-739 (manufactured by Ishihara Sangyo Kaisha, Ltd.) 60.0 parts

[Production of Color Toner 1]
[Color Toner 1] was produced in the same manner as [White Toner 1] except that the following toner raw materials were used.
Polyester resin RN-290 (manufactured by Kao Corporation) 94.7 parts Carnauba wax WA-05 (manufactured by Cerarica NODA Co., Ltd.) 5.3 parts Zirconium salicylate CCA TN-105 0.1 parts (manufactured by Hodogaya Chemical Co., Ltd.)
Copper phthalocyanine cyan pigment FG-7351 (manufactured by Toyo Ink Co., Ltd.) 10.0 parts

[Production of Color Toner 2]
[Color Toner 2] was produced in the same manner as [White Toner 1] except that the following toner raw materials were used.
Polyester resin RN-290 (manufactured by Kao Corporation) 94.7 parts Carnauba wax WA-05 (manufactured by Cerarica NODA Co., Ltd.) 5.3 parts Zirconium salicylate CCA TN-105 (manufactured by Hodogaya Chemical Co., Ltd.) 0.5 parts
Copper phthalocyanine cyan pigment FG-7351 (manufactured by Toyo Ink Co., Ltd.) 10.0 parts

[Color Toner 3] was produced in the same manner as [White Toner 1] except that the following toner raw materials were used.
[Production of Color Toner 3]
Polyester resin RN-290 (manufactured by Kao Corporation) 62.6 parts Polyester resin RN-263 (manufactured by Kao Corporation) 32.1 parts Carnauba wax WA-05 (manufactured by Cerarica NODA Co., Ltd.) 5.3 parts Copper phthalocyanine cyan pigment FG-7351 (manufactured by Toyo Ink Co., Ltd.) 10.0 parts

(Evaluation of toner flow-out start temperature and half flow-out temperature)
The white toner and color toner obtained above were evaluated for toner flow-out start temperature and half flow-out temperature according to the method described above in "Method for measuring flow-out start temperature and half flow-out temperature."
The evaluation results are shown in Table 1.

(Manufacturing of two-component developer)
<Preparation of carrier>
Silicone resin (organostraight silicone) 100 parts Toluene 100 parts γ-(2-aminoethyl)aminopropyltrimethoxysilane 5 parts Carbon black 10 parts

The above mixture was dispersed in a homomixer for 20 minutes to prepare a coating layer forming solution. This coating layer forming solution was applied and dried using a fluidized bed coating device, with the temperature in the fluidized bed controlled at 70°C, to a core material of Mn ferrite particles with a weight-average particle size of 35 μm, so that the average film thickness on the core material surface was 0.20 μm. The resulting carrier was fired in an electric furnace at 180°C for 2 hours to obtain Carrier A.

<Preparation of Two-Component Developer>
The prepared white toner and color toner and carrier A were uniformly mixed and charged for 5 minutes using a Turbler mixer (manufactured by Willy & Bachofen (WAB)) at 48 rpm to prepare two-component developers, respectively. The toner and carrier mixing ratio was adjusted to the toner concentration of the initial developer of the evaluation machine: 7% by mass.

(evaluation)
An image was formed using the two-component developer obtained above, and the image color and washing fastness were evaluated.
The evaluation results are shown in Table 2. The evaluation methods and conditions are as follows.
(Image creation conditions)
(1) The two-component developer of color toner obtained above was set in the cyan station of a RICOH Pro C7200S (manufactured by Ricoh Co., Ltd.), and the development and transfer conditions were adjusted using a process controller so that the toner adhesion amount was 0.40 mg/ ^cm2 , and an unfixed cyan solid image was output on transfer paper (WOW Light 8.0, manufactured by Piotec Corporation).
(2) The two-component developer of white toner obtained above was set at the fifth station of a RICOH Pro C7200S (manufactured by Ricoh Co., Ltd.), and the development and transfer conditions were adjusted using a process controller so that the toner adhesion amount was 1.0 mg/ ^cm2 . An unfixed solid image of white toner was output over the unfixed solid image of cyan on the transfer paper.
(3) The unfixed solid image on the transfer paper was placed on top of a 100% polyester T-shirt fabric and set in a heat press (Piotech Corporation Model HTP234PS1). Heat and pressure were applied at a temperature of Pt (°C) for 20 seconds at a pressure of 600 g/ ^cm2 , after which the transfer paper was peeled off and the toner image was transferred and fixed onto the T-shirt.

(Image color evaluation)
The resulting fixed image was visually evaluated for image color (saturation) according to the following criteria.
[Evaluation criteria]
◎: The image color is vivid. ○: The image is slightly blackish. △: The image is slightly blackish, and there are also some faintly lighter areas of the image. ×: The image is slightly blackish, and there are some lighter areas of the image due to the unevenness of the fabric fibers.

(Washing fastness evaluation)
The fixed images used in the image color evaluation were subjected to a washing fastness test according to the test method of JIS0844:2011 and evaluated according to the following criteria.
[Evaluation criteria]
○: JIS 0844 discoloration gray scale rank 5
△: JIS 0844 discoloration gray scale rank 4 to 3
×: JIS 0844 discoloration gray scale rank 2 to 1

The formulations and evaluation results are shown in Table 2.

The present invention relates to the image forming method of (1) below, but also includes the following (2) to (4) as embodiments.
(1) An image forming method comprising the following steps 1 to 4, characterized in that in the following step 3, an image on a transfer medium is transferred and fixed onto an image receiving substrate at a temperature P _T [°C] that satisfies the following relational expression (1):
Step 1: A step of forming a toner image on a transfer medium using an electrophotographic image forming apparatus with an image forming toner; Step 2: A step of forming an undercoat layer on the toner image using an undercoat layer forming toner; Step 3: A step of combining an image receiving substrate and the undercoat layer and heating and pressing them together to transfer and fix the image on the transfer medium onto the image receiving substrate; Step 4: A step of separating the image transferred and fixed on the image receiving substrate from the transfer medium.
(In formula (1), UT _fb [° C.] is the flow-out start temperature of the toner forming the undercoat layer, and UT _1/2 [° C.] is the half-flow-out temperature of the toner forming the undercoat layer.)
(2) The image forming method according to (1), wherein the outflow start temperature UT _fb [°C], the half outflow temperature UT _1/2 [°C], and the transfer-fixing temperature P _T [°C] of the toner forming the undercoat layer satisfy the following relational expression (2):
(3) The image forming method according to (1) or (2), wherein a half outflow temperature CT _1/2 [°C] of the image forming toner and a half outflow temperature UT _1/2 [°C] of the undercoat layer forming toner satisfy the following relational expression (3):
(4) The image forming method according to any one of (1) to (3) above, wherein the toner for forming the undercoat layer is a white toner or a transparent toner.

Patent No. 5847277

Claims (4)

An image forming method comprising the following steps 1 to 4, characterized in that in step 3, an image on a transfer medium is transferred and fixed onto a fabric at a temperature P _T [°C] that satisfies the following relational expression (1):
Step 1: A step of forming a toner image on a transfer medium using an electrophotographic image forming apparatus with an image forming toner; Step 2: A step of forming an undercoat layer on the toner image using an undercoat layer forming toner; Step 3: A step of combining fabric and the undercoat layer and heating and pressing them together to transfer and fix the image on the transfer medium onto the fabric ; Step 4: A step of separating the image transferred and fixed onto the fabric from the transfer medium.
(In formula (1), UT _fb [° C.] is the flow-out start temperature of the toner forming the undercoat layer, and UT _1/2 [° C.] is the half-flow-out temperature of the toner forming the undercoat layer.) 2. The image forming method according to claim 1, wherein the outflow start temperature UT _fb [°C], the half outflow temperature UT _1/2 [°C], and the transfer-fixing temperature P _T [°C] of the toner forming the undercoat layer satisfy the following relational expression (2):
3. The image forming method according to claim 1, wherein a half outflow temperature CT _1/2 [°C] of the image forming toner and a half outflow temperature UT _1/2 [°C] of the undercoat layer forming toner satisfy the following relational expression (3):
The image forming method according to any one of claims 1 to 3, wherein the toner for forming the undercoat layer is a white toner or a transparent toner.