JPH117147A - Image receiving sheet - Google Patents

Abstract

(57) [Problem] To provide an image receiving sheet which is excellent in toner receptivity and fixability and can form a high quality image without being affected by environmental conditions. SOLUTION: The image receiving sheet comprises a receiving layer formed on at least one surface of a substrate, and an antistatic layer formed on the receiving layer, wherein the antistatic layer comprises at least a thermoplastic resin and a metal oxide. And the metal oxide particles contained in the antistatic layer stabilize the surface electric resistivity of the image receiving sheet within a predetermined range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image receiving sheet,
In particular, the present invention relates to an image receiving sheet used in an electrophotographic copying machine or printer in which image quality is significantly affected by the surface electrical resistivity of the front and back surfaces of the image receiving sheet.

[0002]

2. Description of the Related Art In recent years, a copier or printer using an electrophotographic system has been used to form a full-color image using three colors of yellow, magenta, and cyan, or a mixture of four toners including black and three colors. It is possible.

[0003] The image receiving sheet used in the above-described electrophotographic full-color image formation generally has a structure in which a receptor layer is formed on the surface in order to ensure the receptivity and fixability of the toner. Among such image receiving sheets, for example, an image receiving sheet having high transparency is used in an overhead projector (O / O) at lectures, schools, companies, and other briefings and exhibitions.
HP).

[0004]

However, a conventional image receiving sheet used for forming an electrophotographic full-color image is:
It is susceptible to the effects of static electricity generated during transportation in copiers and printers, and the acceptability and fixing properties of toner are reduced, making it difficult to form high-quality images and causing poor transport. Was.

In order to solve such a problem, an antistatic agent is contained in the receiving layer or an antistatic layer is provided on the receiving layer to maintain the surface electric resistivity of the front and back surfaces of the image receiving sheet within a predetermined range. Such an image receiving sheet has been developed (Japanese Patent Application Laid-Open No. 62-238576).

However, since the conventionally used antistatic agent is an ion conductive material such as a quaternary ammonium salt, the surface electric resistivity greatly changes under the influence of environmental conditions (temperature and humidity) (2). ３3 digits), and a good and stable image quality cannot be obtained.
Therefore, the use of an electron conductive material or a metal conductive material as a material having a constant resistance without being affected by environmental conditions (temperature and humidity) has been studied. For example, although carbon black exhibits a certain resistance due to electron conduction due to mutual contact of structures, the image receiving sheet is colored by its own color, and there is a problem that its use is considerably limited.

The present invention has been made in view of the above circumstances, and provides an image receiving sheet which is excellent in toner receptivity and fixability and can form a high quality image without being affected by environmental conditions. The purpose is to do.

[0008]

In order to achieve the above object, the image receiving sheet of the present invention has a receiving layer on at least one surface of a substrate, and has an antistatic layer on the receiving layer.
The antistatic layer was configured to contain at least a thermoplastic resin and metal oxide particles.

Further, the image receiving sheet of the present invention is configured such that the antistatic layer contains the metal oxide particles in a range of 0.01 to 1.0 g / m ² .

In the image receiving sheet of the present invention, the metal oxide particles are acicular particles, and the major axis is in the range of 0.1 to 2 μm and the aspect ratio is in the range of 10 to 50. The configuration was adopted.

In the image receiving sheet of the present invention, the antistatic layer has a surface electric resistivity of 10 to 30 ° C. and a relative humidity of 30 ° C.
In an environment of up to 80 ° C., the configuration is such that the variation is always within a range of 10 ⁸ to 10 ¹³ Ω / sq and the variation is within one digit.

Further, the image receiving sheet of the present invention is configured so that the parallel line transmittance is 70% or more.

In the present invention, the metal oxide particles contained in the antistatic layer on the receiving layer act as a material having a constant resistance independent of the environment, and the surface electric resistivity of the image receiving sheet is adjusted to a predetermined value. It should be stable within the range.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of the image receiving sheet of the present invention. In FIG. 1, an image receiving sheet 1 of the present invention is formed on a substrate 2, a receiving layer 3 and an antistatic layer 4 laminated on one surface of the substrate 2, and on the other surface of the substrate 2. And a back layer 5. Substrate 2 As the substrate 2 constituting the image receiving sheet 1 of the present invention, a substrate according to the use of the image receiving sheet can be used, and there is no particular limitation. For example, polyolefin resin,
Plastic films or sheets of polyvinyl chloride resin, polyethylene terephthalate resin, polystyrene resin, polycarbonate resin, etc., polyolefins,
Examples include polystyrene-based synthetic paper, plain paper, and coated paper. When the image receiving sheet is used for observing recorded images with transmitted light, such as OHP, a base material made of a thermoplastic resin having transparency, heat resistance, dimensional stability, and rigidity is used. Is preferred. Specifically, a film or sheet of a polyethylene terephthalate resin, a polycarbonate resin, an acrylic resin, a polyvinyl chloride resin, a polypropylene resin, a polystyrene resin, a polyethylene resin, a cellulose diacetate resin, a cellulose triacetate resin, or the like, having a thickness of 10 to 250 μm ,
Preferably, the thickness is about 50 to 180 μm.

When the image receiving sheet of the present invention is used for observing a recorded image with transmitted light such as OHP, the parallel line transmittance of the entire image receiving sheet 1 must be 70 to improve the quality of the transmitted image. % Is preferable. When the image receiving sheet of the present invention is used for the purpose of observing a recorded image by reflected light, the substrate 2 is made of a white opaque plastic film or sheet to which a white pigment, a filler or the like is added, It is preferable to use paper, plain paper, coated paper and the like. Further, by using a translucent substrate, the image receiving sheet of the present invention can be used for electric decoration.

The base material 2 as described above may have a surface subjected to a known easy adhesion treatment such as a primer treatment or a corona discharge treatment for the purpose of improving the adhesion to the receiving layer 3 and the back layer 5. . Receiving Layer 3 The receiving layer 3 constituting the image receiving sheet 1 of the present invention is for receiving toner supplied in an electrophotographic image forming step and maintaining an image formed by the toner.

The receiving layer 3 is mainly composed of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and polyvinyl chloride. Vinyl-vinyl acetate copolymer, polyacrylate, vinyl resin such as polystyrene, polyethylene terephthalate, polyester resin such as polybutylene terephthalate, polyamide, copolymer of polyolefin such as ethylene and propylene and other polymerizable monomers, Examples include ionomers, cellulose resins such as ethyl cellulose and cellulose acetate, and polycarbonate resins. Such a thermoplastic resin preferably has a melting point in the range of 30 to 200 ° C. If the melting point is less than 30 ° C., it is not preferable in terms of storability, and when the image receiving sheets are stacked, the receiving layer 3 adheres to the contact surface, so-called blocking tends to occur. On the other hand, if the melting point exceeds 200 ° C., the toner receptivity of the receiving layer 3 becomes low, and a large amount of energy is required at the time of image formation, which is not preferable.

Receptive layer 3 constituting image receiving sheet 1 of the present invention
Is particularly preferably formed using a water-insoluble thermoplastic resin among the above-mentioned thermoplastic resins. This is when using a water-soluble or water-dispersible thermoplastic resin,
This is because the surface electrical resistivity of the receiving layer 3 is greatly reduced under high humidity due to the effects of salt treatment, emulsifier, and the like. As the water-insoluble thermoplastic resin to be used, a polyester resin is preferable, and in particular, a specific polyester resin disclosed in Japanese Patent Application No. 6-36609 by the present applicant is preferable. Specifically, a polyester resin using a modified bisphenol A represented by the following chemical formula 1 modified with ethylene glycol or propylene glycol as a diol component is preferably used from the viewpoint of toner fixability.

[0020]

Embedded image (In the formula, R is an ethylene group or a propylene group, x and y are each an integer of 1 to 5, and the average value of x and y is 1 to 3.) As a specific example of the above modified bisphenol A,
Propylene glycol-modified bisphenol A represented by the following chemical formula 2 can be given.

[0021]

Embedded image On the other hand, the acid component of the polyester resin is not particularly limited, for example, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, maleic acid, succinic acid, adipic acid, citraconic acid, itaconic acid, sebacic acid, malonic acid, hexa A carboxylic acid or the like can be used.

Among such polyester resins,
A polyester resin using propylene glycol-modified bisphenol A represented by the above chemical formula 2 as a diol component and using fumaric acid as an acid component is excellent in compatibility with toner, and has a good toner receptivity and fixing property. Is possible.

When the above-mentioned polyester resin is used as the water-insoluble thermoplastic resin, one or more of the above-mentioned various thermoplastic resins can be used in combination. In the receiving layer 3, various surfactants, antistatic agents, waxes, oils, and other additives may be mixed and used as long as the effects of the present invention are not impaired.

The receiving layer 3 is formed by a known printing means such as gravure printing or silk-screen printing, or a known printing means such as gravure coat using a coating solution containing various additives as required to the above-mentioned thermoplastic resin. Can be formed on the base material 2 by a coating means, and the thickness of the receiving layer 3 is 0.1 to 10
It can be about μm. Antistatic Layer 4 The antistatic layer 4 constituting the image receiving sheet 1 of the present invention contains at least a thermoplastic resin and metal oxide particles.

The thermoplastic resin for forming the antistatic layer 4 includes polyester resin, polyurethane resin, polyacrylic resin, polyvinyl formal resin, epoxy resin, polyvinyl butyral resin, polyamide resin, and polyamide resin. Examples thereof include ether resins, polystyrene resins, and styrene-acrylic copolymer resins. Of these, polyester resins are preferably used in terms of toner acceptability and compatibility.

Examples of the metal oxide particles contained in the antistatic layer 4 include tin oxide (SnO ₂ ), zinc oxide (ZnO), indium oxide (In ₂ O ₃ ), and titanium oxide (TiO ₂ ). And one or a combination of two or more of them can be used.
Such metal oxide particles have an average particle diameter of 0.01 to
Those having a range of 1.0 μm are preferred.

The metal oxide particles as described above may be those to which a dopant has been added. For example, the dopant may be Sb for SnO ₂ , Al or In for ZnO.
_In the case of ₂ O ₃ , Sn is generally used.

Further, the metal oxide particles as described above may be acicular particles, and in this case, the major axis is 0.1 to 2 μm.
Acicular particles having an aspect ratio in the range of 10 to 50 are preferred. By using such needle-like metal oxide particles, the transparency of the antistatic layer 4 is improved, and when the image receiving sheet is used for observing a recorded image by transmitted light such as OHP, The quality of the transmitted image can be improved.

The antistatic layer 4 is formed by using a coating solution obtained by adding various additives as necessary to the above-described thermoplastic resin and metal oxide particles, using a known coating such as gravure coating, roll coating, wire bar coating, or the like. The antistatic layer 4 can be formed on the receiving layer 3 by a coating means.
It can be about 1.0 μm. When the thickness of the antistatic layer 4 is less than 0.01 μm, it is difficult to obtain a desired stable surface electric resistivity, and when it exceeds 1.0 μm, the surface electric resistivity becomes less than 10 ⁸ Ω / sq, which is preferable. Absent. The antistatic layer 4 contains the above-described metal oxide particles in an amount of 0.01 to 1.0 g / m ² , preferably 0.0 to 1.0 g / m ² .
And those containing in the range of 5~0.5g / m ^2, without surface resistivity of the antistatic layer 4 and the content is less than 0.01 g / m ² is stable, 1.0 g / m ² When it exceeds, the antistatic layer 4 is colored by a color unique to the metal oxide particles,
It is not preferable because image quality is deteriorated. Back Layer 5 The back layer 5 improves the transportability of the image receiving sheet 1 in a copying machine or a printer, and is provided so as to be opposed to the receiving layer 3 with the base material 2 interposed therebetween. It is to have. Such back layer 5
Thermoplastic resins such as acrylic resins, polyester resins, urethane resins, etc., silicone-modified acrylic resins, silicone-modified polyester resins, silicone-modified urethane resins, etc. , Polyester-, polyurethane-, polyamide- or cellulose-based binder resin having, in the main chain thereof, a graft copolymer having at least one releasable segment among a polysiloxane segment, a fluorocarbon segment and a long-chain alkyl segment Or a combination of two or more thermoplastic resins.

The back layer 5 is formed on the receiving layer 3 by using a coating solution obtained by adding an additive as necessary to the above-described thermoplastic resin.
In the same manner as in the formation of
Can be formed on. The thickness of the back layer 5 is 0.1 mm.
It can be set in the range of about 01 to 1 μm.

The image receiving sheet of the present invention is not limited to the above-mentioned embodiments. For example, an image receiving sheet having a receiving layer on both surfaces of a substrate and an antistatic layer provided thereon, and one surface of the substrate May be provided with a receiving layer and an antistatic layer provided thereon, and the other surface may be provided with only an antistatic layer, or the back surface layer may be provided with an antistatic layer.

[0032]

Next, the present invention will be described in more detail with reference to examples. (Example 1) First, a coating liquid for a receiving layer having the following composition was applied to one surface of a 100 μm-thick polyethylene terephthalate (PET) film by a gravure reverse method and dried to form a receiving layer (thickness: 3 μm). .

(Composition of Coating Solution for Receptive Layer) Polyester resin: 30 parts by weight Glass transition point: 60 ° C., melting point: 100 ° C. Acid component: fumaric acid diol component: propylene glycol-modified bisphenol A • Silica fine particles (average particle size) 0.15 parts by weight-Methyl ethyl ketone ... 35 parts by weight-Toluene ... 35 parts by weight Next, an aqueous dispersion (solid content: 25%) of tin oxide particles having an average particle diameter of 0.2 µm and a polyester resin emulsion (glass transition) (67 ° C., solid content: 25%) to prepare the following five kinds of coating solutions for the antistatic layer, apply the coating solutions to the receiving layer by a gravure reverse method, and dry to obtain five kinds of coating solutions. An antistatic layer (1.0 μm thickness) was formed.

(Coating liquid 1 for antistatic layer)-Water dispersion of tin oxide particles ... 30 parts by weight-Polyester resin emulsion ... 30 parts by weight-Water ... 40 parts by weight (Coating liquid 2 for antistatic layer) Water dispersion of tin oxide particles: 20 parts by weight Polyester resin emulsion: 40 parts by weight Water: 40 parts by weight (Coating liquid 3 for antistatic layer) Water dispersion of tin oxide particles: 40 parts by weight・ Polyester resin emulsion 20 parts by weight ・ Water 40 parts by weight (Coating liquid 4 for antistatic layer) ・ Aqueous dispersion of tin oxide particles 10 parts by weight ・ Polyester resin emulsion 50 parts by weight ・ Water 40 parts by weight Part (Coating liquid 5 for antistatic layer) ・ Aqueous dispersion of tin oxide particles: 50 parts by weight ・ Polyester resin emulsion: 10 parts by weight ・ Water: 40 parts by weight The P is a base layer coating solution
The other surface of the ET film was applied by a gravure reverse method and dried to form a back layer (thickness: 1 μm), thereby obtaining image receiving sheets (samples 1 to 5).

(Composition of Coating Solution for Back Layer) Acrylic resin (solid content 15%) 20 parts by weight BR-85 manufactured by Mitsubishi Rayon Co., Ltd. Silica fine particles (average particle diameter 3 μm) 0.1 parts by weight Parts: methyl ethyl ketone: 40 parts by weight; toluene: 40 parts by weight The content of tin oxide particles in the antistatic layer of each image receiving sheet (samples 1 to 5) is shown in Table 1 below.

A coating solution 6 for an antistatic layer having the following composition
Was used to obtain an image receiving sheet (comparative sample) in the same manner as described above.

(Coating liquid 6 for antistatic layer) Quaternary ammonium salt surfactant 0.1 part by weight Isopropyl alcohol 100 parts by weight

[0038]

[Table 1] The image receiving sheets (Samples 1 to 5 and Comparative Samples) thus produced were evaluated for environmental dependency of the surface electric resistivity of the antistatic layer under the following conditions, and the results are shown in Table 2 below.

Environmental Dependence of Surface Electrical Resistivity A high resistivity meter manufactured by Advantest Co., Ltd.
The surface electric resistivity of the antistatic layer of the image receiving sheet is measured in each environment of 30% relative humidity at 50 ° C., 50% relative humidity at 25 ° C., and 80% relative humidity at 30 ° C.

The image quality of the image receiving sheets (samples 1 to 5 and comparative samples) and the environmental dependency of transportability were evaluated under the following conditions, and the results are shown in Table 3 below.

Environmental Dependence of Image Quality Using a full-color copying machine pretail manufactured by Ricoh Co., Ltd., a relative humidity of 30% at a temperature of 10 ° C. and a relative humidity of 50 at a temperature of 25 ° C.
%, An image of a color chart is formed on an image receiving sheet under each environment of a temperature of 30 ° C. and a relative humidity of 80%, and the image quality is visually evaluated according to the following criteria.

(Evaluation Criteria) ：: Good without toner transfer failure.

Δ: There is a little toner transfer failure.

×: Many toner transfer failures.

Environment Dependency of Transport Suitability Using a full-color copying machine manufactured by Ricoh Co., Ltd., the transportability of an image receiving sheet from paper supply to paper discharge during image formation was measured at a temperature of 10 ° C. and a relative humidity of 30%. The evaluation is made under the following criteria under each environment of 25 ° C. and 50% relative humidity and 30 ° C. and 80% relative humidity.

(Evaluation Criteria) ：: No transport trouble occurred in continuous 10 image formation.

Δ: Conveyance trouble occurred on 1 to 5 sheets after continuous image formation of 10 sheets.

C: Trouble occurred on 6 to 10 sheets when 10 images were continuously formed.

[0049]

[Table 2]

[0050]

[Table 3] As shown in Tables 2 and 3, Samples 1 to 5 have less environmental dependence of the surface electric resistivity of the antistatic layer than the comparative samples, and particularly, Samples 1 to 3 always have 10 ⁸ to 10 ⁸ under each environment. 10
^It was within the range of ¹³ Ω / sq, and the variation was within one digit. The image quality was good and the transportability was excellent. (Example 2) First, in the same manner as in Example 1, the PE
A receiving layer (thickness: 3 μm) was formed on one surface of the T film.

Next, the following eight kinds of antistatic layers were prepared using an aqueous dispersion (solid content: 25%) of acicular tin oxide particles and a polyester resin emulsion (glass transition point: 67 ° C., solid content: 25%). Was prepared, and the coating liquid was applied on the receiving layer by a gravure reverse method and dried to form eight kinds of antistatic layers (0.1 μm in thickness).

(Coating Liquid A for Antistatic Layer) Aqueous dispersion of acicular tin oxide particles: 30 parts by weight Long axis length = 0.5 μm, aspect ratio = 20 Polyester resin emulsion: 30 parts by weight Water ... 40 parts by weight (Coating solution B for antistatic layer)-Aqueous dispersion of acicular tin oxide particles-20 parts by weight Long axis length = 0.5 m, aspect ratio = 20-Polyester resin emulsion-40 parts by weight- Water: 40 parts by weight (Coating solution C for antistatic layer) Aqueous dispersion of acicular tin oxide particles: 40 parts by weight Long axis length = 0.5 μm, aspect ratio = 20 Polyester resin emulsion: 20 parts by weight Water: 40 parts by weight (coating liquid D for antistatic layer) Aqueous dispersion of acicular tin oxide particles: 5 parts by weight Long axis length = 0.5 μm, aspect ratio = 20 Polyester resin emulsion: 55 parts by weight Department Water: 40 parts by weight (coating solution E for antistatic layer) Aqueous dispersion of acicular tin oxide particles: 50 parts by weight Long axis length = 0.5 μm, aspect ratio = 20 Polyester resin emulsion: 10 parts by weight Part: Water: 40 parts by weight (Coating solution F for antistatic layer) Aqueous dispersion of acicular tin oxide particles: 30 parts by weight Long axis length = 0.2 μm, aspect ratio = 10 Polyester resin emulsion: 30 Parts by weight Water: 40 parts by weight (Coating solution G for antistatic layer) Aqueous dispersion of acicular tin oxide particles: 30 parts by weight Long axis = 2 μm, aspect ratio = 50 Polyester resin emulsion: 30 parts by weight Part: Water: 40 parts by weight (Coating liquid H for antistatic layer) Aqueous dispersion of acicular tin oxide particles: 30 parts by weight Long axis = 0.05 μm, aspect ratio = 5 Polyester resin emulsion: 30 Heavy Next, a back layer (thickness: 1 μm) was formed on the other surface of the PET film as a base material to obtain image receiving sheets (samples A to H) in the same manner as in Example 1. . Table 4 below shows the content, major axis length, and aspect ratio of the acicular tin oxide particles in the antistatic layer of each image receiving sheet.

[0053]

[Table 4] With respect to the image receiving sheets (samples A to H) thus produced, the environmental dependence of the surface electric resistivity of the antistatic layer was evaluated in the same manner as in Example 1, and the results are shown in Table 5 below.

For the above-mentioned image receiving sheet (samples A to I) and the image receiving sheet (sample 1, comparative sample) produced in Example 1, the image quality and the environmental dependence of transportability were evaluated. The results are shown in Table 6. The evaluation of image quality was performed under the following conditions to which evaluation conditions for an OHP image-receiving sheet were added, and the evaluation of transport suitability was performed in the same manner as in Example 1.

Environmental Dependence of Image Quality Using a full-color copier made by Ricoh Co., Ltd., a relative humidity of 30% at a temperature of 10 ° C. and a relative humidity of 50 at a temperature of 25 ° C.
%, An image of a color chart is formed on an image receiving sheet under each environment of a temperature of 30 ° C. and a relative humidity of 80%, the image quality is visually evaluated, and an OHP apparatus (OHPF1 manufactured by Fuji Xerox Co., Ltd.) is used. To evaluate the transmission image.

(Evaluation Criteria) ：: Good without toner transfer failure.

Δ: There is a little toner transfer failure.

X: Many toner transfer failures.

[0059]

[Table 5]

[0060]

[Table 6] As shown in Tables 5 and 6, Samples A to H have little environmental dependence of the surface electric resistivity of the antistatic layer, and particularly Samples A to C, F, and G always have 10 ⁸ to 10 under each environment. ¹³ Ω / s
q and the variation is within one digit,
The image quality when used for HP was good, and the transportability during copying was excellent.

[0061]

As described above in detail, according to the present invention, a receiving layer is formed on at least one surface of a substrate, and an antistatic layer is formed on the receiving layer. Is an image receiving sheet containing at least a thermoplastic resin and metal oxide particles, so that the metal oxide particles different from the ion conductive material have a constant resistance independent of environmental conditions (temperature, humidity) And stabilizes the surface electrical resistivity of the image receiving sheet within a predetermined range, thereby stably and improving the toner receptivity and fixing property of the image receiving sheet, thereby enabling high-quality image formation by an electrophotographic method. At the same time, the transportability in an electrophotographic copying machine or printer is improved. By making the metal oxide particles acicular particles, a highly transparent image receiving sheet can be obtained while stabilizing the surface electric resistivity within a predetermined range. Such an image receiving sheet is useful for OHP.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an image receiving sheet of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image receiving sheet 2 substrate 3 receiving layer 4 antistatic layer 5 back layer

Claims (5)

[Claims] 1. A substrate having a receiving layer on at least one surface thereof, an antistatic layer provided on the receiving layer, wherein the antistatic layer contains at least a thermoplastic resin and metal oxide particles. Characteristic image receiving sheet. 2. The image receiving sheet according to claim 1, wherein the antistatic layer contains the metal oxide particles in a range of 0.01 to 1.0 g / m ² . 3. The metal oxide particles have a major axis of 0.1-2.
The image-receiving sheet according to claim 1, wherein the image-receiving sheet is acicular particles having an aspect ratio in a range of 10 to 50 μm. 4. The surface electric resistivity of the antistatic layer is always within a range of 10 ⁸ to 10 ¹³ Ω / sq in an environment of a temperature of 10 to 30 ° C. and a relative humidity of 30 to 80 ° C., and a change amount thereof. The image receiving sheet according to any one of claims 1 to 3, wherein is within one digit. 5. The image receiving sheet according to claim 1, wherein the parallel line transmittance is 70% or more.