JP2013025207A - Image forming method and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method capable of obtaining a printed matter having high durability, without causing peeling of an adhesive layer, even when an image having a high image density is displayed, and to provide the printed matter.SOLUTION: The image forming method includes a process for developing an electrostatic latent image to form a toner image, transferring the toner image onto the adhesive layer, and pressing the toner image to bury toner particles in the adhesive layer. In the case of developing the electrostatic latent image formed based on original image data, when it is assumed that one or more of a plurality of image areas having unit areas respectively, formed by sectioning an obtained toner image is a high density image area where an average toner adhesion amount exceeds 2.5 g/m, image processing for forming a small toner non-adhesion area whose unit area is 6×10mor more and 1,000×10mor less in the high density image area is preformed for the original image data, to obtain corrected image data, and the electrostatic latent image is formed based on the corrected image data.

Description

  The present invention relates to a printed matter on which an image is displayed by embedding toner particles in an adhesive layer, and an image forming method for forming the printed matter.

There are various image forming methods such as an offset method, an ink jet method, and an electrophotographic method. However, in any type of image forming method, energy saving has been demanded in recent years in consideration of the environmental burden at the time of printing. It has been.
In the electrophotographic image forming method, when the fixing method is a heating method, a large amount of running energy is required for the fixing process. Therefore, as a non-heating method fixing method that saves energy, an image is formed on an image supporting substrate. A method of forming a printed matter by holding and fixing a toner image by burying toner particles in an adhesive layer (matrix) using a formed gel adhesive or the like (hereinafter, this method is also referred to as “matrix fixing method”). Has been proposed (see Patent Document 1).

JP 2010-145440 A

However, it has been found that the following problems occur in the printed matter obtained by this matrix fixing method.
In the printed matter obtained by the matrix fixing method, when a full-color image having a high image density or an image having a large solid portion is displayed, the toner image is formed by superposing toner particles in multiple layers. However, since the adhesive material hardly permeates between the toner particles constituting the inside of the toner image or between the image supporting substrate and the toner particles in a state where the toner image is held in the adhesive layer, the toner The surface part and side part (edge part) of the image are in contact with the adhesive layer, but there is no contact with the adhesive layer in the other parts, and this causes toner particles that do not have adhesive strength to themselves. It has been found that there is a problem that an adhesive layer holding a toner image is peeled off from an image supporting substrate in a printed matter that is used to display an image having a high image density. In particular, the problem of peeling off of the adhesive layer is considered to occur remarkably when a borderless image having a high image density is displayed because the side surface portion of the toner image is exposed to the outside.

  The present invention has been made on the basis of the above-described circumstances, and an object of the present invention is to laminate an adhesive layer made of a gel-like adhesive material on an image supporting substrate, and hold a toner image on the adhesive layer. In the image forming method for obtaining the printed matter, the image forming method and the printed matter, in which even when an image having a high image density is displayed, the adhesive layer is not peeled off and a highly durable printed matter is obtained. It is to provide.

The image forming method of the present invention is an image forming method in which a pressure-sensitive adhesive layer made of a gel-like pressure-sensitive adhesive material is laminated on an image-supporting base material, and a printed matter in which a toner image is held on the pressure-sensitive adhesive layer is obtained.
An electrostatic latent image is formed by exposing a uniformly charged photoconductor, the electrostatic latent image is developed with toner to form a toner image, and the toner image is gelled on an image supporting substrate. Electrostatically transferred onto the pressure-sensitive adhesive layer of the base material sheet formed by laminating a pressure-sensitive adhesive layer made of an adhesive material, and presses the base material sheet carrying the electrostatically-transferred toner image to thereby apply the toner to the pressure-sensitive adhesive layer. Having a step of holding a toner image by burying toner particles constituting the image,
When an electrostatic latent image formed based on original image data is developed, one or more of a plurality of image areas each having a unit area formed by dividing the obtained toner image is an average. When it is assumed that the toner density is a high density image area exceeding 2.5 g / m ² , the original image data has an area of 6 × 10 ⁻¹¹ m ² per high density image area. The correction image data is obtained by performing image processing for forming a minute toner non-attachment area of 1000 × 10 ⁻¹¹ m ² or less, and an electrostatic latent image is formed based on the correction image data. Features.

The image forming method of the present invention is an image forming method for obtaining a printed material in which an adhesive layer made of a gel-like adhesive material is laminated on an image supporting substrate and a toner image is held on the adhesive layer. ,
An electrostatic latent image is formed by exposing a uniformly charged photoconductor, the electrostatic latent image is developed with toner to form a toner image, and the toner image is electrostatically formed on an image supporting substrate. The toner particles constituting the toner image are pressed onto the pressure-sensitive adhesive layer by pressing the transferred and electrostatically-transferred image supporting substrate on which an adhesive layer made of a gel-like pressure-sensitive adhesive material is laminated. Having a step of holding the toner image by burying,
When an electrostatic latent image formed based on original image data is developed, one or more of a plurality of image areas each having a unit area formed by dividing the obtained toner image is an average. When it is assumed that the toner density is a high density image area exceeding 2.5 g / m ² , the original image data has an area of 6 × 10 ⁻¹¹ m ² per high density image area. The correction image data is obtained by performing image processing for forming a minute toner non-attachment area of 1000 × 10 ⁻¹¹ m ² or less, and an electrostatic latent image is formed based on the correction image data. Features.

In the image forming method of the present invention, a unit area related to the image region is 1 × 10 ⁻⁵ m ^{2 to} 5 × 10 ⁻⁴ m ² .
For each image area
An image analysis step for determining whether or not a toner non-attachment region is to be formed according to the average toner adhesion amount, and for an image region for which a toner non-attachment region is to be formed, the image determined in the analysis step It is preferable to obtain the corrected image data through an image processing step for performing the image processing on the region.

In the image forming method of the present invention, in the image processing, the total area ratio of the non-toner area in the high density image area (total area (m ² ) / unit area (m ² ) of non-toner area) However, it is preferable that the toner non-attachment region is formed so as to be 0.1 or more.

  In the image forming method of the present invention, the pressure-sensitive adhesive material constituting the pressure-sensitive adhesive layer is preferably at least one of silicone gel and acrylic resin crosslinked body gel, and the thickness of the pressure-sensitive adhesive layer is preferably 30 to 120 μm. .

  Furthermore, in the image forming method of the present invention, it is preferable that the volume-based median diameter of the toner particles is 3 to 10 μm.

  The printed matter of the present invention is obtained by the image forming method described above.

  According to the image forming method of the present invention, the toner image is formed according to the corrected image data in which a minute toner non-attached area is formed in an image area having a high image density in the original image data. In addition to the surface portion and the edge portion, the empty dots formed by reflecting the toner non-adhering area in the toner image are positively provided with a contact point with the adhesive layer. Excellent adhesiveness and adhesiveness between the pressure-sensitive adhesive layer and the image supporting substrate, whereby a printed material having high durability that does not peel off the pressure-sensitive adhesive layer even when an image having a high image density is displayed can be obtained.

FIG. 3 is a schematic diagram for explaining an example of a transfer process and a toner embedding process of the image forming method according to the first embodiment of the present invention, where (a) is a state in which a toner image is carried on a transparent sheet material. FIG. 4B is a diagram illustrating a state where a toner image is transferred onto an adhesive layer of a base sheet, and FIG. 5C is a diagram illustrating a state where the toner image is held on the adhesive layer. FIG. 3 is a schematic view showing a part of a state where a toner image is carried on an adhesive layer of a base sheet in the image forming method of the present invention, cut out in the thickness direction. 4 is a flowchart for explaining image processing in the image forming method of the present invention. It is the schematic of the original image data for demonstrating the image process in the image formation method of this invention. FIG. 6 is a schematic diagram for explaining an example of a transfer step and a toner embedding step in an image forming method according to a second embodiment of the present invention, in which (a) shows a toner image transferred onto an image supporting substrate. State (b) is a diagram showing a state in which the toner image is held on the adhesive layer.

  Hereinafter, the present invention will be described in detail.

<First Embodiment>
FIG. 1 is a schematic diagram for explaining an example of a transfer process and a toner embedding process in the image forming method of the present invention, wherein (a) is a diagram showing a state in which a toner image is carried on a transparent sheet material; (B) is a diagram showing a state in which the toner image is transferred onto the adhesive layer of the base sheet, (c) is a diagram showing a state in which the toner image is held on the adhesive layer, and FIG. FIG. 4 is a schematic diagram showing a part of a state in which a toner image is carried on an adhesive layer of a base sheet in the image forming method, cut out in a thickness direction.
In the image forming method of the present invention, as shown in FIG. 1, an adhesive layer 15 made of a gel-like adhesive material is laminated on an image supporting substrate 11 and a toner image T is held on the adhesive layer 15. This is a method for obtaining the object P.
Specifically, an electrostatic latent image forming step (1) for forming an electrostatic latent image by exposing a uniformly charged photoreceptor (not shown), and developing the electrostatic latent image with toner A toner image forming step (2) for forming a toner image T, and a base material sheet 17 formed by laminating an adhesive layer 15 made of a gel adhesive material on the image supporting base material 11. The toner image T is electrostatically transferred onto the adhesive layer 15 via the transparent sheet material 13, specifically, the toner image T is once electrostatically transferred onto the transparent sheet material 13, and the transparent sheet material 13 on which the toner image T is carried. A transfer step (3) (see FIG. 1A) for laminating the toner image T with the base material sheet 17 so that the toner image T and the adhesive layer 15 are in contact with each other, and a base material sheet carrying the electrostatically transferred toner image T 17 is pressed to embed toner particles constituting the toner image T in the adhesive layer 15. Thus, the toner image T is held (see FIG. 1B), and the toner embedding step (4) is performed. By performing these steps, the toner image T is fixed on the base sheet 17 and the toner is This is a method of forming a printed matter P on which an image by an image T is displayed.

(1) Electrostatic latent image forming step In the present invention, in this electrostatic latent image forming step, an electrostatic latent image is formed based on the corrected image data acquired as follows.
In other words, the corrected image data is a plurality of image areas each having a unit area formed by dividing a toner image obtained when an electrostatic latent image formed based on original image data is developed. When one or more is assumed to be a high-density image region with an average toner adhesion amount exceeding 2.5 g / m ² , the area per image in the high-density image region is 6 × 10 6 for the original image data. It is acquired by performing image processing for forming a minute toner non-attachment region that is ⁻¹¹ m ² or more and 1000 × 10 ⁻¹¹ m ² or less.

  Specifically, as shown in FIG. 3 and FIG. 4, the original image data (S1) is divided into image areas having unit areas (S2), and the toner non-attachment area is determined according to the average toner adhesion amount in each image area. The image analysis step (S3) for determining whether or not the image region is to be formed is performed, and the high density image region 20 is determined to be the image region in which the toner non-attachment region is to be formed in the image analysis step. The empty dot forming area 21 composed of all the areas is selected (S4), and a toner non-attached area is formed in each high density image area 20 of the empty dot forming area 21 (S5). The data relating to the empty dot formation area 21 is changed to data in which the toner non-attachment area is formed, and the area other than the empty dot formation area 21 in the original image data, that is, the empty dot formation area 21 is changed. A non-formation area 26 consisting of all of the low density image areas 25 determined to be an image area that is not required to form a toner non-attachment area in the image analysis step, which is automatically determined together with the selection of the image formation area 21. No modification is made to the data related to (S6), and the corrected image data (S7) is obtained by combining them.

  In the present invention, the original image data includes, for example, digital data acquired from the outside and digital data obtained by reading a document with an appropriate reading device and converting it into digital data.

Toner non-attachment area When the area of each of the toner ^images is 6 × 10 ⁻¹¹ m ² or more and 1000 × 10 ⁻¹¹ m ² or less, empty dots T ₀ formed by reflecting the toner non-attached area in the obtained printed product P and Despite being able to act as a contact (hereinafter also referred to as “internal contact”) between the adhesive layer 15 and the toner particles or the image supporting substrate 11, the desired image density obtained from the original image data is obtained. It is possible to display an image having a density at which the density difference is not visually recognized. On the other hand, when the area of each non-toner area is less than 6 × 10 ⁻¹¹ m ² , the adhesive material can be infiltrated into empty dots T ₀ formed by reflecting the non-toner area. This is not possible, and the empty dot T ₀ cannot act as an internal contact. In addition, when the area of each non-toner area exceeds 1000 × 10 ⁻¹¹ m ² , the density difference from the intended image density obtained from the original image data is visually recognized. The desired image cannot be displayed.

The unit area for dividing the original image data is 1 × 10 ⁻⁵ m ^{2 to} 5 × 10 ⁻⁴ m ^2, and is particularly preferably 2 × 10 ⁻⁴ m ² .
By setting the unit area within the above range, it is possible to accurately form a toner non-attachment region only in an image region having a high image density. On the other hand, when the unit area is too small, the image processing requires a lot of time and processing efficiency is low. Note that the image unit area was obtained as a less than 1 × 10 ^-5 m ^2, compared to the image obtained by the unit area 1 × 10 ^-5 m ^2, the difference visually is hardly recognized. On the other hand, if the unit area is too large, the toner non-attached area cannot be formed in an accurate image area, and the adhesive layer may be peeled off.

In the image processing step, the total area ratio of the non-toner area (the total area (m ² ) / unit area (m ² ) of the non-toner area) in each high-density image area 20 of the empty dot formation area 21 is 0. It is preferable that the toner non-attachment region is formed so as to be 1 or more, preferably 0.1 to 0.3.
When the total area ratio of the toner non-adhesion region is 0.1 or more, the number of internal contacts is provided so as to prevent the adhesive layer 15 from being peeled off. On the other hand, when the total area ratio of the toner non-adhering region is too small, the number of internal contacts is reduced, and there is a possibility that a sufficient effect of preventing peeling of the adhesive layer cannot be obtained. In addition, when the total area ratio of the toner non-attached area is excessive, there is a possibility that the density difference from the intended image density obtained from the original image data is visually recognized.

(2) Toner Image Forming Step The toner image forming step in the image forming method of the present invention can be performed using the following toner and utilizing a conventionally known electrophotographic method.

〔toner〕
The toner used in the toner image forming step of the image forming method of the present invention is composed of, for example, toner particles in which a colorant is dispersed in a resin. The toner particles may further include a charge control agent and a magnetic material as desired. Powders, waxes and the like may be contained.

[Toner resin]
The toner resin constituting the toner particles includes styrene resin, (meth) acrylic resin, styrene- (meth) acrylic copolymer obtained by using styrene monomer and (meth) acrylic monomer. Various known resins such as polymer resins, vinyl resins such as olefin resins, polyester resins, polyamide resins, polycarbonate resins, polyethers, polyvinyl acetate resins, polysulfones, epoxy resins, polyurethane resins, urea resins, etc. Resin can be used. These can be used alone or in combination of two or more.
A (meth) acrylic acid monomer for obtaining a styrene- (meth) acrylic copolymer resin is a general term for a methacrylic acid monomer and an acrylic acid monomer. Specific examples of the body include methacrylic acid (CH ₂ ═C (CH ₃ ) COOH) and methacrylic acid ester derivatives. Examples of acrylic acid monomers include acrylic acid (CH ₂ ═CHCOOH) and acrylic ester derivatives.

[Colorant]
As the colorant constituting the toner particles, various organic or inorganic pigments as exemplified below can be used.
Examples of the colorant for black toner include carbon black, magnetic material, and iron / titanium composite oxide black. Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. be able to. Examples of the magnetic material include ferrite and magnetite.
Examples of yellow colorants for yellow toner include C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, etc., and C.I. I. Pigment Yellow 14, 17, 17, 74, 93, 94, 138, 155, 180, 185, etc., and mixtures thereof can also be mentioned.
As a magenta colorant for magenta toner, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, etc. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, etc. The mixture of can also be mentioned.
As a cyan colorant for cyan toner, C.I. I. Solvent Blue 25, C.I. I. Solvent Blue 36, C.I. I. Solvent Blue 60, C.I. I. Solvent Blue 70, C.I. I. Solvent Blue 93, C.I. I. Solvent Blue 95 and other pigments such as C.I. I. Pigment blue 1, 7, 15, 60, 62, 66, 76, and the like.
These colorants can be used alone or in combination of two or more.
The addition amount of the colorant is preferably 0.5 to 20 parts by mass, more preferably 2 to 10 parts by mass with respect to 100 parts by mass of the toner resin.

[Magnetic powder]
When the toner particles are configured to contain magnetic powder, examples of the magnetic powder include magnetite, γ-hematite, and various ferrites.
The addition amount of the magnetic powder is preferably 10 to 500 parts by mass, more preferably 20 to 200 parts by mass with respect to 100 parts by mass of the toner resin.

[Charge control agent]
Further, in the case where the toner particles are configured to contain a charge control agent, the charge control agent is not particularly limited as long as it is a substance that can give positive or negative charge by frictional charging, and there are various known ones. Can be mentioned.
As described above, the toner particles are configured to contain the charge control agent, whereby the chargeability of the toner is improved.
The addition amount of the charge control agent is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the toner resin.

〔wax〕
Furthermore, when the toner particles are configured to contain a wax, various known waxes can be used as the wax. As the wax, it is particularly preferable to use a polyolefin-based wax such as low molecular weight polypropylene, polyethylene, or oxidized polypropylene or polyethylene.
The addition amount of the wax is preferably 0.1 to 30 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the toner resin.

[Method for producing toner particles]
A method for producing such toner particles is not particularly limited, and a pulverization method, an emulsion dispersion method, a suspension polymerization method, a dispersion polymerization method, an emulsion polymerization method, an emulsion polymerization aggregation method, and other known methods. And so on.

[Average toner particle size]
The average particle diameter of the toner is preferably 3 to 10 μm in terms of volume-based median diameter. When the average particle diameter of the toner is 3 to 10 μm, the toner particles can be surely embedded in the adhesive layer 15, and excellent reproducibility of fine lines can be obtained. When the average particle diameter of the toner exceeds 10 μm, it may be difficult to embed the toner particles in the adhesive layer 15, and when the average particle diameter of the toner is less than 3 μm, electrostatic repulsion between the toner particles may occur. The controllability at the time of toner image formation is inferior, such as toner scattering due to force.

  The volume-based median diameter of toner particles is measured and calculated using a measuring device in which a computer system equipped with data processing software “Software V3.51” is connected to “Coulter Multisizer 3” (manufactured by Beckman Coulter). It is what is done. Specifically, 0.02 g of toner is added to 20 mL of a surfactant solution (for example, a surfactant solution in which a neutral detergent containing a surfactant component is diluted 10-fold with pure water for the purpose of dispersing the toner). Then, ultrasonic dispersion was performed for 1 minute to prepare a toner dispersion, and this toner dispersion was placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in a sample stand. Pipette until the indicated concentration is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 50 μm, the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume-based median diameter.

[Average circularity of toner particles]
The above toner particles preferably have an average circularity represented by the following formula (S) of 0.700 to 1.000, more preferably 0.850 to 1.000.
Formula (S): Average circularity = circumference of circle obtained from equivalent circle diameter / perimeter of particle projection image

(External additive)
The above toner particles can constitute the toner as it is, but in order to improve fluidity, chargeability, cleaning properties, etc., the toner particles are provided with a so-called post-treatment agent, a fluidizing agent and a cleaning aid. The toner may be constituted by adding external additives such as the above.
As the post-treatment agent, for example, inorganic oxide fine particles composed of silica fine particles, alumina fine particles, titanium oxide fine particles, etc., inorganic stearate compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, or strontium titanate, titanium Inorganic titanic acid compound fine particles such as zinc acid are listed. These can be used individually by 1 type or in combination of 2 or more types.
These inorganic fine particles are preferably subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil or the like in order to improve heat-resistant storage stability and environmental stability.
The total amount of these various external additives added is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner. In addition, various external additives may be used in combination.

(Developer)
The toner as described above can be used for image formation as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner is used as a one-component developer for image formation, either a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner is used. Can be used. In addition, when the toner is used for image formation as a two-component developer, the carrier is a conventionally known material such as a metal such as iron, ferrite, or magnetite, or an alloy of such a metal with a metal such as aluminum or lead. Magnetic particles can be used, and ferrite particles are particularly preferable. As the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a resin-dispersed carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.

(3) Transfer Step The transfer step in the image forming method of the present invention can be performed using a conventionally known electrophotographic method.

[Base material sheet]
The base material sheet 17 used in the image forming method of the present invention is obtained by forming the adhesive layer 15 on the surface of the image supporting base material 11.
It is preferable that the thickness of this base material sheet 17 shall be 100-250 micrometers, for example.

(Image support substrate)
As the image supporting substrate 11, an appropriate one can be used. For example, plain paper from thin paper to thick paper, high-quality paper, coated printing paper such as art paper or coated paper, commercially available Japanese paper, Examples include postcard paper, polypropylene synthetic paper, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, polyimide film, and cloth.
The thickness of the image support substrate 11 is preferably set to, for example, 50 to 150 μm.

(Adhesive layer)
In the present invention, the pressure-sensitive adhesive material constituting the pressure-sensitive adhesive layer 15 is a gel-like material, and has toner particle embedding properties capable of embedding toner particles.

As an adhesive material, from the viewpoint of reliably obtaining toner particle embedding properties, it does not have fluidity in a state where an external force such as a pressing force is not applied, and expresses a fluid state when an external force is applied. Preferably there is. Specifically, for example, it is in a gel state in a normal state and can have a thixotropic property that changes to a sol state when an external force is applied.
In particular, when the toner particles are embedded by an external force, the toner particles preferably have fluidity (hereinafter also referred to as “specific fluidity”) such that the degree of change in the particle shape is suppressed to be small. .
Specifically, the material having a specific fluidity means a material having a penetration of 30 or more measured according to JIS K2207 in a state where an external force for embedding toner particles is applied. As the material, a material having a higher penetration is preferable, but a material having a penetration of 100 or less is particularly preferable.
A toner image T formed by electrostatically adhering each toner particle on the photoreceptor is maintained in such a state that the electrostatic charge in each toner particle is maintained by using the material having such specific fluidity. And can be held in the adhesive layer 15.
The pressure-sensitive adhesive material constituting the pressure-sensitive adhesive layer 15 preferably has a Young's modulus of 10 ³ to 10 ⁶ N / m ² .
When the adhesive material has a Young's modulus in the above range, the toner particles constituting the toner image T can be sufficiently maintained and fixed.

  Further, the pressure-sensitive adhesive material forming the pressure-sensitive adhesive layer 15 is incompatible with a resin constituting the toner particles (hereinafter also referred to as “toner resin”) from the viewpoint of reliably obtaining toner particle embedding properties. Further, as the adhesive material, a material having high affinity with the toner particles is preferable.

Adhesive materials include silicone, acrylic, vinyl, urethane, and other resins, gels of high molecular compounds such as elastomer or rubber and organic solvents or oils, and gels of water-soluble polymers and aqueous solvents. Can be used.
Specifically, the silicone resins include dimethylsiloxane, diphenylsiloxane, methylvinylsiloxane, methylphenylsiloxane, fluorosiloxane, trifluorosiloxane, trifluoropropylsiloxane, chloromethylsiloxane, cyanoethylsiloxane, polyether siloxane, fluoro Examples thereof include polyether siloxane and aminosiloxane.
Examples of acrylic resins include 2-ethylhexyl acrylate and n-butyl acrylate, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, acrylamide derivatives, hydroxyethyl acrylate, and glycidyl acrylate. Examples include polymers.
Examples of vinyl resins include polyvinyl acetate, ethylene-vinyl acetate copolymer, acrylic-vinyl acetate copolymer, polyvinyl acetal, polyvinyl butyral, phenol-vinyl butyral copolymer, polyvinyl pyrrolidone, and polyvinyl chloride. Is mentioned.
Examples of urethane resins include polyurethane prepolymers obtained by reacting polyols and polyisocyanates. Examples of polyols include 1,2-polybutadiene polyol, 1,4-polybutadiene polyol, and poly (pentadiene / butadiene) polyol. , Poly (butadiene / styrene) polyol, poly (butadiene / acrylonitrile) polyol, etc., and polyisocyanates include diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl isocyanate, xylylene diisocyanate, lysine diisocyanate, hexamethylene. Diisocyanate, isophorone diisocyanate, methylene bis (cyclohexyl isocyanate), etc.
Further, as water-soluble polymers, natural polymer polysaccharides such as xanthan gum, carrageenan, pullulan, furseleran, curdlan, gelatin, collagen, etc .; sodium alginate, calcium alginate natural low molecular polysaccharide; polyacrylic acid; sodium polyacrylate Polyvinyl alcohol and the like.
Examples of the aqueous solvent include water, methyl alcohol, ethyl alcohol, ethylene glycol, propylene glycol, polyethylene glycol, and glycerin.

As the gel constituting the adhesive material, it is particularly preferable to use silicone gel or acrylic resin crosslinked gel.
Due to its flexibility, the polymer having a crosslinked structure such as silicone gel or acrylic resin crosslinked gel is not only the surface portion, edge portion, or peripheral portion of the toner non-attached region, but also between the toner particles in the vicinity or the toner. It is presumed that it easily penetrates between the particles and the image supporting substrate 11. Therefore, by using an adhesive material containing a polymer having such a crosslinked structure, the effect of preventing peeling of the adhesive layer can be reliably obtained.

  The thickness of the adhesive layer 15 varies depending on the thickness of the toner image T to be held and the type of the adhesive material. For example, when the gel contained in the adhesive material is a silicone gel or an acrylic resin crosslinked gel, the thickness is 30 to 120 μm. It is preferred that When the thickness of the pressure-sensitive adhesive layer 15 is within the above range, the toner image T can be sufficiently included, and the handling properties required as a printed matter are sufficiently ensured. On the other hand, when the thickness of the pressure-sensitive adhesive layer 15 is less than 30 μm, the toner particles constituting the toner image T may protrude from the surface of the pressure-sensitive adhesive layer 15 and the toner particles may fall off the printed matter P. On the other hand, when the thickness of the adhesive layer 15 exceeds 120 μm, the weight and thickness of the printed matter to be obtained increase, which is not preferable from the viewpoint of handling properties as a paper-like medium.

[Transparent sheet material]
The transparent sheet material 13 used in this image forming method is translucent and has a sheet shape.
Examples of the transparent sheet material 13 include sheets made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), and polystyrene (PS).

  The thickness of the transparent sheet material 13 is preferably 10 to 200 μm, more preferably 25 to 100 μm.

(4) Toner embedding process In the toner embedding process, in order to embed the toner particles constituting the toner image T in the adhesive layer 15, an external force can be applied, and the external force applied to embed the toner particles is: Depending on the mechanical strength of the toner particles constituting the toner image T and the type of the adhesive material constituting the adhesive layer 15, for example, a pressing force having a size of 1.00 × 10 ^{3 to} 1.00 × 10 ⁸ Pa is used. It can be pressure.
Examples of the external force for burying the toner particles in the adhesive layer 15 include an electrostatic force applied by an appropriate transfer device, a pressing force applied by an appropriate pressing device, and a combination thereof.
Although heating is not required when the toner particles are embedded in the adhesive layer 15, heat treatment may be performed at a low temperature, for example, about 60 to 80 ° C., in order to obtain a high-quality printed matter.

In the image forming method of the present invention, when the particle shape degree of the toner particles used for forming the toner image T is A, and the particle shape degree of the toner particles constituting the toner image T held in the adhesive layer is B. It is preferable that the following relational expression (I) is satisfied.
Relational expression (I): 1.0 ≧ B / A ≧ 0.9
Here, the particle shape degree of the toner particles is expressed by (minimum diameter of the projected image / maximum diameter of the projected image).
(B / A) indicating the degree of change in the degree of particle shape of the toner particles before being used for forming the toner image T and after being embedded in the adhesive layer 15 is small due to being in the range of the relational expression (I). The printed matter can be formed by an external force, that is, by a small amount of energy. On the other hand, when (B / A) indicating the degree of change in particle shape is less than 0.9, a large amount of energy is required to obtain the printed matter P, which is not preferable because the environmental load is large. .

  Specifically, the particle shape degree A of the toner particles used for forming the toner image T is determined by peeling off the toner image T electrostatically formed on the photosensitive member, and then scanning electron microscope (SEM) “JSM”. -7401F "(manufactured by JEOL Ltd.), an image with a magnification of 2,000 times is taken into a" Luzex image analyzer "(manufactured by Nireco), and each toner particle has a maximum projected image of the particle. The diameter and minimum diameter are measured, the particle shape obtained by dividing the minimum diameter by the maximum diameter is obtained, and the average value of the particle shape of 100 toner particles is calculated.

  Further, the particle shape degree B of the toner particles after being embedded in the adhesive layer 15 is specifically determined by using a transmission electron microscope (TEM) “JEM” of a cross section of the printed matter P obtained by this image forming method. -1400 "(manufactured by JEOL Ltd.), an image with a magnification of 2,000 times is taken into a" Luzex image analyzer "(manufactured by Nireco), and each individual toner particle has a maximum projected image of the particle. The diameter and minimum diameter are measured, the particle shape obtained by dividing the minimum diameter by the maximum diameter is obtained, and the average value of the particle shape of 100 toner particles is calculated.

  Specifically, the particle shape degree A of the toner particles used for forming the toner image T is preferably 0.40 to 1.00, and more preferably 0.60 to 1.00. Further, the particle shape degree B of the toner particles after being embedded in the adhesive layer 15 is specifically preferably 0.40 to 1.00, more preferably 0.60 to 1.00.

The relational expression (I) can be achieved, for example, by using hard toner particles having a 10% deformation strength of 1 to 100 MPa.
This 10% deformation strength is a value measured in a compression test mode using a micro compression tester “MCT-W201” (manufactured by Shimadzu Corporation).

[Printed matter]
In the printed matter P obtained by the above image forming method, the toner image T having the empty dot T ₀ formed by reflecting the toner non-attached region is held in the adhesive layer 15 on the image supporting substrate 11. Further, the transparent sheet material 13 is laminated on the adhesive layer 15. The transparent sheet material 13 may be peeled off after the toner particles constituting the toner image T are buried in the adhesive layer 15 and the toner image T is fixed, as shown in FIG. You may make it function as a surface protection material, without peeling.
Such a printed matter P can be used as a seal, for example, by peeling the image supporting substrate 11 and using the peeled surface as an adhesive surface.

According to the image forming method as described above, the toner image T is formed according to the corrected image data in which a minute toner non-attached area is formed in an image area having a high image density in the original image data. In addition to the surface portion and the edge portion of the image T, a contact point with the adhesive layer is positively provided in the empty dot T ₀ formed by reflecting the toner non-adhering region in the toner image. 15 and the toner image T, and the adhesion between the pressure-sensitive adhesive layer 15 and the image supporting substrate 11, thereby preventing the pressure-sensitive adhesive layer 15 from peeling even when an image having a high image density is displayed. A printed matter P having the property is obtained.

Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above example, and various modifications can be made.
For example, the transfer process is not limited to transferring the toner image T onto the adhesive layer 15 via the transparent sheet material 13, and may be directly transferred onto the adhesive layer 15.

<Second Embodiment>
As shown in FIG. 5, the image forming method according to the second embodiment of the present invention uses, for example, an image fixing sheet 12 in which an adhesive layer 15 is formed on a transparent sheet material 13 to form a toner image. The toner image T formed in the process is electrostatically transferred onto the image support substrate 11 directly or via an intermediate transfer member (see FIG. 5A), and the electrostatically transferred toner image The image fixing sheet 12 is laminated on the image supporting substrate 11 carrying T so that the adhesive layer 15 of the image fixing sheet 12 is in contact with the toner image T, and pressed in this state to the toner on the adhesive layer 15. By burying the toner particles constituting the image T, the toner image T is held (see FIG. 5B), whereby the toner image T is fixed to the adhesive layer 15 on the image supporting base 11 and the toner image is fixed. An image by T was displayed Other forming a Ebutsu P is a method having the same requirements as in the first embodiment.
The transparent sheet material 13 may be peeled off after the toner particles constituting the toner image T are embedded in the adhesive layer 15 and the toner image T is fixed, as shown in FIG. 5B. You may make it function as a surface protection material, without peeling.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

<Example 1>
(1) Preparation of image fixing sheet After applying silicone gel A “SEI891H” (manufactured by Dow Corning Toray) on a transparent polyethylene terephthalate (PET) film base (transparent sheet material) having a thickness of 100 μm with a bar coater, By curing, a flexible adhesive layer having a thickness of 50 μm and a penetration of 45 was formed, thereby obtaining an image fixing sheet [1] in which the adhesive layer was laminated on the transparent sheet material.
(2) Preparation of Developer A ferrite carrier in which a cyclohexyl methacrylate resin is coated on a ferrite core particle having a volume-based median diameter of 50 μm, and a toner having a glass transition point (Tg) of 40 ° C. and a volume-based median diameter of 6.5 μm. The toner composed of particles was sufficiently mixed to prepare a two-component developer having a toner concentration of 7%.
(3) Image formation Based on the corrected image data obtained by subjecting the following original image data to image processing by the full-color multi-function peripheral “bizhub C 253” (manufactured by Konica Minolta Business Technologies) with the fixing device removed. After the toner image is transferred onto white glossy paper “POD128” (manufactured by Oji Paper Co., Ltd.) (image supporting substrate) using a developer, the adhesive layer contacts the toner image with the image fixing sheet [1]. After that, the adhesive is held on the image supporting substrate by passing through the unfixed fixing device without heating and pressing (pressing force: 5 × 10 ⁵ Pa). A printed material [1] in which the layers were laminated and the transparent sheet material was laminated on the outermost surface was obtained.

The original image data and image processing conditions are as follows.
○ Original image data ・ Image on which a solid patch (4 cm × 2.5 cm, area 10 cm ² ) having a toner adhesion amount of 8 g / m ² is formed ○ Image processing conditions • Unit area: 2 × 10 ⁻⁴ m ²
-Area per non-toner area: 8 × 10 ⁻¹¹ m ²
-Total area ratio of non-toner area: 0.15

<Example 2>
(1) Preparation of substrate sheet Silicone gel A “SE1891H” (manufactured by Dow Corning Toray) was coated with a bar coater on white glossy paper “POD128” (manufactured by Oji Paper Co., Ltd.) (image supporting substrate). Thereafter, by curing, a flexible adhesive layer having a thickness of 50 μm and a penetration of 45 is formed, thereby obtaining a substrate sheet [1] in which the adhesive layer is laminated on the image supporting substrate. It was.
(2) Preparation of developer A ferrite carrier in which a cyclohexyl methacrylate resin is coated on a ferrite core particle having a volume-based median diameter of 50 μm, and a toner having a glass transition point (Tg) of 40 ° C. and an average particle diameter of 6.5 μm. Then, a two-component developer having a toner concentration of 7% was prepared.
(3) Image formation Based on the corrected image data obtained by performing image processing on the following original image data by “bizhub C 253” (manufactured by Konica Minolta Business Technologies) with the fixing device removed, the above two-component developer is used. After the toner image is transferred onto a transparent polyethylene terephthalate (PET) film base (transparent sheet material) having a thickness of 100 μm, the toner image is superimposed on the substrate sheet [1] in a state where it is in contact with the adhesive layer. After that, the adhesive unit holding the toner image is laminated on the image supporting substrate by passing through the removed fixing device without being heated and pressed, and the transparent sheet material is laminated on the outermost surface. A printed product [2] was obtained.

<Example 3>
Silicone gel B “SE1740” (manufactured by Toray Dow Corning) is applied on a transparent polyethylene terephthalate (PET) film base (transparent sheet material) having a thickness of 100 μm with a bar coater, and then cured to give a thickness of 50 μm. Thus, an image fixing sheet [2] obtained by laminating an adhesive layer on a transparent sheet material was obtained.
In Example 1, a printed matter [3] was obtained in the same manner except that the image fixing sheet [2] was used instead of the image fixing sheet [1].

<Example 4>
Adhesive layer by applying acrylic resin cross-linked gel “Technogel AG” (manufactured by Sekisui Plastics Co., Ltd.) to a thickness of 50 μm on a transparent polyethylene terephthalate (PET) film base (transparent sheet material) having a thickness of 100 μm. Thus, an image fixing sheet [3] obtained by laminating an adhesive layer on a transparent sheet material was obtained.
In Example 1, a printed matter [4] was obtained in the same manner except that the image fixing sheet [3] was used instead of the image fixing sheet [1].

<Comparative Example 1>
In Example 1, a printed matter [5] was obtained in the same manner except that the toner image was formed according to the original image data without performing image processing. The toner image of the printed product [5] is one in which no toner non-attachment area is formed.

<Comparative example 2>
In Example 1, a print product [6] was obtained in the same manner except that image processing was performed according to the following image processing conditions. In this printed product [6], the total area ratio of the non-toner area is the same as that in Example 1, but the area per non-toner area is too small.
○ Image processing conditions ・ Unit area: 2 × 10 ⁻⁴ m ²
-Area per non-toner area: 4 × 10 ⁻¹¹ m ²
-Total area ratio of non-toner area: 0.15

<Comparative Example 3>
A printed matter [7] was obtained in the same manner as in Example 1 except that image processing was performed according to the following image processing conditions. In this printed product [7], the total area ratio of the non-toner area is the same as that in Example 1, but the area per non-toner area is excessive.
○ Image processing conditions ・ Unit area: 2 × 10 ⁻⁴ m ²
-Area per non-toner area: 1200 × 10 ^-11 m ²
-Total area ratio of non-toner area: 0.15

<Example 5>
In Example 1, a printed matter [8] was obtained in the same manner except that image processing was performed according to the following image processing conditions.
○ Image processing conditions ・ Unit area: 2 × 10 ⁻⁴ m ²
-Area per non-toner area: 8 × 10 ⁻¹¹ m ²
-Total area ratio of non-toner area: 0.08

<Comparative example 4>
In Example 1, a printed matter [9] was obtained in the same manner except that the following image processing was performed.
The image processing was performed so that the average toner adhesion amount per unit area of 2 × 10 ⁻⁴ m ² of the original image data was 2.5 g / m ² or less in any unit area.
This printed product [9] is obtained by reducing the image density of the entire image.

<Comparative Example 5>
After applying the adhesive “RC paper cement” (manufactured by Fukuoka Kogyo Co., Ltd.) on a transparent polyethylene terephthalate (PET) film base (transparent sheet material) having a thickness of 100 μm with a bar coater, the thickness is increased by drying and curing. An adhesive layer having a thickness of 50 μm was formed, whereby an image fixing sheet [4] in which the adhesive layer was laminated on the transparent sheet material was obtained.
In Example 1, a printed matter [10] was obtained in the same manner except that the image fixing sheet [4] was used instead of the image fixing sheet [1]. This print [10] uses an adhesive as an adhesive material constituting the adhesive layer. The adhesive does not penetrate between the toner particles or between the toner particles and the image supporting substrate, unlike the silicone gel and the acrylic resin crosslinked gel.

<Example 6>
Silicone gel A “SE1891H” (manufactured by Dow Corning Toray) is applied on a transparent polyethylene terephthalate (PET) film base (transparent sheet material) having a thickness of 100 μm with a bar coater, and then cured to a thickness of 30 μm. Thus, an image fixing sheet [5] in which an adhesive layer is laminated on a transparent sheet material was obtained.
In Example 1, a printed matter [11] was obtained in the same manner except that the image fixing sheet [5] was used instead of the image fixing sheet [1].

<Example 7>
Silicone gel A “SE1891H” (manufactured by Dow Corning Toray) is applied on a transparent polyethylene terephthalate (PET) film base (transparent sheet material) having a thickness of 100 μm with a bar coater, and then cured to a thickness of 120 μm. Thus, an image fixing sheet [6] obtained by laminating an adhesive layer on a transparent sheet material was obtained.
In Example 1, a printed matter [12] was obtained in the same manner except that the image fixing sheet [6] was used instead of the image fixing sheet [1].

<Example 8>
A printed product [13] was obtained in the same manner as in Example 1, except that a toner having an average particle diameter of 13.4 μm was used instead of the toner having an average particle diameter of 6.5 μm.

[Evaluation]
The above printed matter [1] to [13] were evaluated for image density difference and adhesiveness. The results are shown in Table 1.

(1) Image density difference The printed material is read from the transparent sheet material side with a scanner “GT-9800F” (manufactured by EPSON) at 600 dpi, and the number of pixels of each color level is analyzed to obtain a color level average value C. The degree R of the difference between the color level average values was calculated according to R) and evaluated accordingly.
Formula (R): R = (| C ₀ −C |) / C ₀
However, in the above formula (R), C ₀ is the average value of each color level of the printed material [5] of Comparative Example 1 in which the image processing according to the present invention is not performed.
It can be determined that the smaller the R is, the smaller the density difference between before and after the image processing is, that is, the smaller the image density difference is.
When R ≦ 5%, the image density difference is hardly recognizable by visual observation even if it is aligned with the printed material [5] of Comparative Example 1 where image processing is not performed (practical use).
When 5% <R ≦ 10%, the image density difference can hardly be visually recognized when separately compared with the printed material [5] of Comparative Example 1 where image processing is not performed. Or it is not a difference to worry about.
When 10% <R ≦ 20%, a difference in image density is visually recognized when compared separately with the print [5] of Comparative Example 1 in which image processing is not performed (unusable).
When 20% <R, the image density difference is large even when compared separately with the printed material [5] of Comparative Example 1 where image processing is not performed, and the same image cannot be recognized (unusable).

(2) Adhesiveness A
A solid patch portion (image region) of 4 cm × 2.5 cm in the printed material was cut out in the thickness direction. The image-supporting substrate (paper) side of this cut-out sample is an acrylic cylinder (a: φ4 cm, b: φ10 cm, c: φ15 cm) with a smooth surface, and the long side (4 cm) of the sample is a cylinder. The adhesiveness was evaluated according to the following evaluation criteria, depending on the diameter of the cylindrical body where the adhesive layer was peeled off. It can be determined that the smaller the diameter of the cylindrical body from which the adhesive layer does not peel, that is, the higher the curvature, the higher the adhesion.
-Evaluation criteria-
3: Adhesive layer does not float when affixed to any of a, b, and c, and has sufficient adhesiveness.
2: When pasted on a, the end of the sample floats, but when pasted on b, c, the adhesive layer does not float. There is a slight deficiency in adhesiveness, but there is no problem in using it as a print.
1: When affixed to a and b, the end of the sample floats, but when affixed to c, the adhesive layer does not float. There is a lack of adhesiveness, and there is a problem in use as a printed matter.
0: The adhesive layer floats when pasted on any of a, b, and c. Adhesiveness is insufficient and cannot be used as a print.

(3) Adhesiveness B
A solid patch portion (image region) of 4 cm × 2.5 cm in the printed material was cut out in the thickness direction. The image supporting substrate (paper) side of the cut out sample is attached to an acrylic flat plate having a smooth surface, and the flat plate is left in a vertical state for 3 days, and the adhesive layer is peeled off from the flat plate. The adhesiveness was evaluated according to the following evaluation criteria. It can be determined that the smaller the diameter of the cylindrical body from which the adhesive layer does not peel, that is, the higher the curvature, the higher the adhesion.
-Evaluation criteria-
3: Peeling of the adhesive layer does not occur within 3 days. Sufficient adhesion is obtained.
2: Peeling of the adhesive layer occurred within 24 hours and 3 days. Although there is a lack of adhesiveness, there is no problem in using it as a print.
1: Immediately after the start of the experiment, the adhesive layer does not peel off, but the adhesive layer peels off within 24 hours. There is a lack of adhesiveness, and there is a problem in use as a printed matter.
0: Peeling of the adhesive layer occurs immediately after the start of the experiment. Adhesiveness is inadequate and cannot be used as a printed matter.

DESCRIPTION OF SYMBOLS 11 Image support base material 12 Image fixing sheet 13 Transparent sheet material 15 Adhesive layer 17 Base material sheet 20 High density image area 21 Empty dot formation area 25 Low density image area 26 Non-formation area P Printed matter T Toner image T ₀ Empty dot

Claims (7)

An image forming method for obtaining a printed matter in which an adhesive layer made of a gel-like adhesive material is laminated on an image supporting substrate, and a toner image is held on the adhesive layer,
An electrostatic latent image is formed by exposing a uniformly charged photoconductor, the electrostatic latent image is developed with toner to form a toner image, and the toner image is gelled on an image supporting substrate. Electrostatically transferred onto the pressure-sensitive adhesive layer of the base material sheet formed by laminating a pressure-sensitive adhesive layer made of an adhesive material, and presses the base material sheet carrying the electrostatically-transferred toner image to thereby apply the toner to the pressure-sensitive adhesive layer. Having a step of holding a toner image by burying toner particles constituting the image,
When an electrostatic latent image formed based on original image data is developed, one or more of a plurality of image areas each having a unit area formed by dividing the obtained toner image is an average. When it is assumed that the toner density is a high density image area exceeding 2.5 g / m ² , the original image data has an area of 6 × 10 ⁻¹¹ m ² per high density image area. The correction image data is obtained by performing image processing for forming a minute toner non-attachment area of 1000 × 10 ⁻¹¹ m ² or less, and an electrostatic latent image is formed based on the correction image data. An image forming method. An image forming method for obtaining a printed matter in which an adhesive layer made of a gel-like adhesive material is laminated on an image supporting substrate, and a toner image is held on the adhesive layer,
An electrostatic latent image is formed by exposing a uniformly charged photoconductor, the electrostatic latent image is developed with toner to form a toner image, and the toner image is electrostatically formed on an image supporting substrate. The toner particles constituting the toner image are pressed onto the pressure-sensitive adhesive layer by pressing the transferred and electrostatically-transferred image supporting substrate on which an adhesive layer made of a gel-like pressure-sensitive adhesive material is laminated. Having a step of holding the toner image by burying,
When an electrostatic latent image formed based on original image data is developed, one or more of a plurality of image areas each having a unit area formed by dividing the obtained toner image is an average. When it is assumed that the toner density is a high density image area exceeding 2.5 g / m ² , the original image data has an area of 6 × 10 ⁻¹¹ m ² per high density image area. The correction image data is obtained by performing image processing for forming a minute toner non-attachment area of 1000 × 10 ⁻¹¹ m ² or less, and an electrostatic latent image is formed based on the correction image data. An image forming method. A unit area of the image region is 1 × 10 ⁻⁵ m ^{2 to} 5 × 10 ⁻⁴ m ² ;
For each image area
An image analysis step for determining whether or not a toner non-attachment region is to be formed according to the average toner adhesion amount, and for an image region for which a toner non-attachment region is to be formed, the image determined in the analysis step The image forming method according to claim 1, wherein the corrected image data is acquired through an image processing step of performing the image processing on the area. In the image processing, the total area ratio of the non-toner area in the high density image area (total area (m ² ) / unit area (m ² ) of non-toner area) is 0.1 or more. The image forming method according to claim 1, wherein a landing area is formed.   The pressure-sensitive adhesive material constituting the pressure-sensitive adhesive layer is at least one of silicone gel and acrylic resin crosslinked body gel, and the thickness of the pressure-sensitive adhesive layer is 30 to 120 μm. An image forming method according to claim 1.   The image forming method according to claim 1, wherein the toner particles have a volume-based median diameter of 3 to 10 μm. A printed matter obtained by the image forming method according to claim 1.

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