JPH10133409A - Electrophotographic transparent recording material and heat fixing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic transparent recording material giving a color or full-color image having satisfactory color tone reproducibility at the time of use in an overhead projector by specifying the acid value, wt. average mol.wt. and glass transition temp. of a water-soluble resin. SOLUTION: This electrophotographic transparent recording material has a toner receiving layer B based on a water-soluble resin having an acid value of 120-164, preferably 139-164. A thermoplastic resin having a wt. average mol.wt. of 10,000-15,000, preferably 10,000-13,000 and 77-95 deg.C, preferably 80-95 deg.C glass transition temp. by DSC is suitable for use as the water-soluble resin. It is preferable that wax is further incorporated into the toner receiving layer B so as to further improve releasability from a fixing roll and to reduce the graininess of a toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-transmitting recording material for electrophotography for forming a toner image and a heat fixing method for fixing a toner image on the recording material.

[0002]

2. Description of the Related Art Conventionally, in a general full-color image forming method, a photosensitive member of a photosensitive drum is uniformly charged, image exposure is performed by a laser beam modulated by a magenta image signal of a document, and a static image is formed on the photosensitive drum. An electrostatic latent image is formed, and the electrostatic latent image is developed by a magenta developing device to form a magenta toner image. Next, the magenta toner developed on the photosensitive drum by the transfer charger is transferred to the conveyed recording material.

Next, the photosensitive drum after the above-mentioned development and transfer is neutralized by a neutralization charger, and after cleaning,
It is charged again by the primary charger, and in the same manner as above,
The cyan toner image is formed on the photosensitive drum, and the cyan toner image is transferred onto the recording material on which the magenta toner image has been transferred. The color toner image is transferred to the recording material. Further, the recording material having the four color toner images is fixed by a fixing unit such as a fixing roller by the action of heat and pressure to form a full-color image.

In recent years, such an image forming apparatus is not limited to a mere business processing copier for copying an original manuscript, but also a printer as a computer output device or a personal copy for individuals. It is starting to be used.

In addition to the field represented by such a laser beam printer, the development of a plain paper fax machine using a basic engine has been rapidly developing.

[0006] Therefore, in the image forming apparatus as described above, smaller and lighter, and higher speed, higher image quality and higher reliability have been pursued, and the machine is composed of simpler elements in various points. It is becoming. As a result, the performance required of the toner has become higher, and if the performance of the toner is not improved, a better machine cannot be realized.

Further, in recent years, demands for color copying have rapidly increased in accordance with various needs for copying. In order to copy original color images more faithfully, further higher image quality and higher resolution are desired. From these viewpoints, the toner used in the color image forming method needs to have good melting properties and color mixing properties when heat is applied, and has a low softening point and a low melting temperature and a sharp melting property. A high toner is required. By using such a toner having a high sharp-melt property, the color reproduction range of a copy can be widened and a color copy faithful to the original image can be obtained.

However, such a color toner having a high sharp melt property generally has a high affinity with a fixing roller and tends to be easily offset to the fixing roller.
In particular, in the case of a fixing unit in a color image forming apparatus, since magenta, cyan, yellow, and black toner layers are formed on a recording material, offset tends to occur particularly due to an increase in toner layer thickness. There is a tendency.

Conventionally, in order to improve the releasability of the toner from the fixing roller, for example, the surface of the fixing roller is formed of a material having excellent releasability from the toner (for example, silicone rubber or fluorine resin). Further, the surface is coated with a thin film of a highly releasable liquid such as silicone oil or fluorine oil in order to prevent offset and prevent the surface of the roller from being fatigued. This method is extremely effective in preventing offset of the toner, but requires a device for supplying an anti-offset liquid, which complicates the fixing device, and the oil application constitutes a fixing roller. This causes delamination between layers, which results in a problem of shortening the life of the fixing roller.

[0010] On the other hand, with the recent various needs for copying,
As the recording material, various papers, coated papers, plastic films, and the like are used. Above all, an overhead projector (OH
The need for an OHP sheet for utilizing P) has attracted attention. In particular, the OHP sheet, unlike paper, has a low oil absorption capacity, so that the oil used in the above method adheres to the surface of the recording material, and as a result, the resulting copied OHP sheet has a sticky feeling due to oil application. However, the quality of the image is deteriorated. Further, there is a possibility that silicone oil or the like is evaporated by heat and contaminates the inside of the machine, and further, a problem such as treatment of recovered oil may occur.

Therefore, there is a great expectation for establishing a fixing system which does not require oil application at the time of fixing an image which solves these problems, and for developing a new toner for achieving the same.

A toner containing a release agent such as wax for solving the above problem is disclosed in JP-A-61-273554 and the like.

In a toner containing a wax, the wax that melts at a low temperature improves the thermal conductivity in the toner, and as a result, a low-temperature fixation becomes possible. More preferably, since the wax melted at the time of fixing also functions as a release agent, high-temperature offset can be prevented without applying a release agent such as oil to the fixing roller.

On the other hand, when a color toner image or a full-color toner image is formed on a transparent laminate film by using an electrophotographic method having a dry developing method, and these images are projected using an OHP device, the film Although the upper full-color image shows a sufficient color developing property, the projected image shows a grayish color tone as a whole, and a phenomenon in which the color tone reproduction range becomes very narrow occurs. This phenomenon is caused by the fact that the unfixed toner image formed on the smooth laminate film does not flow sufficiently due to heating at the time of fixing and has a granularity, so that the incident light is scattered at the time of projection and a shadow is formed on the screen. The result of forming
Occurs. In particular, in the intermediate tone portion where the image density is low,
A phenomenon occurs in which the color tone to be reproduced becomes gray.

On the other hand, when a toner image formed on a recording material such as plain paper is visually observed, a reflected image of light applied to the fixed toner image is visually observed. Even if some graininess remains, the effect on image quality is small. However, when observing or projecting a toner image on a screen with transmitted light as in an OHP apparatus, if the residual shape caused by the toner particles is clear, light scattering causes deterioration in light transmission and the color tone becomes gray. It will be scrambled. Therefore, the recording material used in the OHP apparatus is required to have the effect of reducing the granularity of the toner after fixing the color image and improving the light transmission.

As means for reducing the granularity of the toner after fixing and improving the light transmittance, Japanese Patent Application Laid-Open No. 2-263642 discloses
As described in JP-A-7-199515, a method of burying toner particles in a toner receiving layer by heat and pressure during fixing is used. At this time, if a resin that is not sufficiently plasticized by heat and pressure at the time of fixing is used for the toner receiving layer, penetration of the toner particles into the receiving layer is extremely reduced, and the projected image shows a gray color tone.

However, in the above-mentioned OHP sheet, wax is contained in the toner as a release agent, and the release agent such as oil is not applied to the surface of the fixing roller.
No consideration is given to the oilless fusing process.
Therefore, when the toner as described above is used, in the toner image area, although the offset resistance is good due to the action of the wax contained in the toner as a release agent, a portion where the toner image is not formed is formed. In this case, the action of the wax as a release agent is insufficient, and a phenomenon in which the toner receiving layer made of a thermoplastic resin sticks to the fixing roller tends to occur. Therefore, it is desired to improve a recording material suitable for an oilless fixing process using the toner.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light-transmitting recording material for electrophotography which solves the above-mentioned problems and a heat fixing method using the same.

That is, when used in an overhead projector (OHP), a projected color image does not become grayish even in an intermediate tone portion having a low image density, and a color image having good tone reproducibility. An object of the present invention is to provide a light-transmitting recording material for electrophotography capable of obtaining a full-color image, and a method for heating and fixing a toner image using the same.

Further, an object of the present invention is to provide a light-transmitting recording material for electrophotography having a toner receiving layer which does not stick to the surface of a fixing means at the time of image fixing, and a method for heat-fixing a toner image using the same. Is to provide.

Still another object of the present invention is to provide a light-transmitting recording material for electrophotography capable of obtaining a color or full-color transparency sheet having excellent transparency and a method of heating and fixing a toner image using the same. Is to provide.

[0022]

The above object is achieved by the following constitutions of the present invention.

According to the present invention, there is provided a light-transmissive recording material for electrophotography having at least a light-transmissive substrate and a toner-receiving layer mainly composed of a water-soluble resin formed on the substrate. Having a valence in the range of 120 to 164, a weight average molecular weight (Mw) in the range of 10,000 to 15,000, and a glass transition point (Tg) in the range of 77 to 95 ° C. Recording material for recording.

Further, the present invention provides a heat fixing method for fixing a toner image formed on a light transmissive recording material to the light transmissive recording material by the action of heat and pressure of a heat fixing means.
The light-transmissive recording material has at least a light-transmissive substrate and a toner-receiving layer mainly formed of a water-soluble resin formed on the substrate, and the water-soluble resin has an acid value of 120 to 164.
And a weight average molecular weight (Mw) of 10,000 to
15,000, and a glass transition point (Tg) of 77.
To 95.degree. C.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, have found that a toner-receiving layer on a light-transmitting substrate has a thermoplastic acid-soluble resin having a specific acid value. The present inventors have found that the use of a toner can provide a light-transmissive recording material for electrophotography having excellent releasability from the surface of the fixing means and excellent fixability of toner particles. In other words, the light-transmitting recording material for electrophotography of the present invention is excellent in the light-transmitting recording material from the fixing means without sticking to the surface of the fixing means even when a large amount of oil is not separately supplied to the fixing means. And good color reproducibility is exhibited even when the obtained toner image is projected on a screen by an OHP.

The recording material according to the present invention will be described with reference to FIG.

In FIG. 1, A indicates a light-transmitting resin base film as a base material layer of a recording material, and B indicates a light-transmitting toner receiving layer.

The base film A needs to have heat resistance that does not cause significant thermal deformation due to heating during heat fixing or heat and pressure fixing. Base film A is ASTM D6
Under the measurement conditions of 4.6 kg / cm ² described in No. 84, preferably 145 ° C. or more, more preferably 150 ° C.
Those having a heat deformation temperature of about 230 ° C. are preferable. Specifically, as the base film A, 14
Has a heat distortion temperature of 5 ° C or higher, and a maximum operating temperature of 100 ° C
Polyethylene terephthalate (P
ET), polyester, polyamide or polyimide. Among them, polyethylene terephthalate is particularly preferred in terms of heat resistance and transparency.

The thickness of the base film A needs to be such that wrinkles do not occur even when the film is softened by heating at the time of fixing. For example, in the case of polyethylene terephthalate, the thickness may be 50 μm or more. Even if it is a light transmitting film, the light transmittance decreases as the thickness increases,
The thickness of the base film A is preferably 50 to 300 μm.
m, more preferably 70 to 200 μm, and still more preferably 100 to 150 μm.

The toner receiving layer B can be formed on a substrate by dissolving or dispersing a thermoplastic resin and a wax component in an aqueous medium, using a bar coating method, a dip method, or the like.
A method of applying to the surface of the light-transmissive base film A by a coating method such as a spray method or a spin coating method, and drying at room temperature or by heating.

Further, a heat-resistant resin film as a base material layer,
For the purpose of improving the adhesion to the toner receiving layer, it is also preferable to perform a surface treatment such as a plasma treatment or a corona discharge treatment or to form an easily adhesive layer.

Next, the constituent material of the toner receiving layer B of the light transmitting recording material of the present invention will be described in detail. Toner receiving layer B
The water-soluble resin, which is a main forming material of the above, has an acid value of 120 to
It is good to be in the range of 164, more preferably in the range of 139 to 164. If the acid value is smaller than 120, the affinity for the surface of the fixing roller covered with a fluorine-based resin having a small surface energy becomes high, and the sticking becomes remarkable, which is not preferable. On the other hand, if the acid value is larger than 164, the compatibility with the binder resin used for the toner is inferior, and the embedding of the toner particles in the receiving layer is disadvantageous. The acid value of the water-soluble resin in the present invention is measured according to JIS-K3504.

The water-soluble resin used in the present invention is not particularly limited as long as the acid value is within the above range. For example, conventionally known polyvinyl alcohol, modified polyvinyl alcohol, polyethylene oxide, acetic acid Examples include various thermoplastic resins such as vinyl alcohol, celluloses, gelatins, polyester resins, methacrylic resins, acrylic resins, and styrene-acrylic resins.

In the present invention, the weight average molecular weight is 10
000 to 15,000, more preferably 10,000
A thermoplastic resin having a range of １３13000 is preferably used. That is, if it is less than 10,000, sticking to the surface of the fixing means becomes remarkable, and if it is more than 15,000, the softening property of the toner receiving layer B at the time of heating and fixing is insufficient, and the toner particles are buried in the toner receiving layer, and The effect of reducing the graininess is impaired and the image quality is reduced, which is not preferable.

In the present invention, the weight average molecular weight of the thermoplastic resin was determined from the molecular weight distribution measured by GPC.
The GPC measurement was performed by GPC-150C (manufactured by Waters) under the following conditions. That is, the column is stabilized in a heat chamber at 40 ° C., and THF (tetrahydrofuran) as a solvent is flown through the column at this temperature at a flow rate of 1 ml per minute, and the sample concentration is 0.05 to
The THF sample solution of the resin prepared to 0.6% by weight is 50 to
Measure by injecting 200 μl. Then, the molecular weight distribution of the sample is determined from the relationship between the logarithmic value of the calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number, and the molecular weight is calculated. As a standard polystyrene sample for preparing a calibration curve, commercially available standard polystyrene manufactured by Tosoh Corporation was used, and the molecular weight was 6 × 10 ² , 2.1 × 10 ³ , and 4 × 1.
0 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 1
0 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.
48 × 10 ⁶ was used. The detector used was an R1 (refractive index) detector, and the column was TSKgel manufactured by Tosoh.
A combination of G1000H, G2000H, G3000H was used.

Further, the thermoplastic resin used in the present invention has a glass transition temperature (Tg) determined by DSC.
It is preferably in the range of 77C to 95C, more preferably in the range of 80C to 95C. If the glass transition temperature of the thermoplastic resin is lower than 77 ° C., sticking to the fixing roller is extremely undesirable. On the other hand, when the temperature exceeds 95 ° C., the softening of the toner receiving layer at the time of fixing becomes insufficient, and the effect of burying the toner particles in the toner receiving layer to reduce the granularity of the toner is undesirably impaired.

In the present invention, the glass transition temperature (T
The DSC measurement of g) was performed using an internal heating type input compensation type differential scanning calorimeter with high accuracy based on the measurement principle. As such a measuring device, for example, a DSC- manufactured by PerkinElmer, Inc.
7 can be used. The measurement method is ASTM D
Performed according to 3418-82. In the present invention,
A measurement sample of 5 to 20 mg, preferably 10 mg, is precisely weighed, placed in an aluminum pan, and heated to 100 to 200 ° C. in a nitrogen atmosphere at a rate of 10 ° C./min using an empty aluminum pan as a reference. Measured with warming. In the present invention, in this heating process, each baseline before and after the shift of the baseline is extrapolated in the direction of each other, and the intersection of the line at the intermediate point and the differential heat curve is defined as Tg.

The transparent toner-receiving layer B constituting the light-transmitting recording material of the present invention can be further improved in releasability from a fixing roller and heat-fixed in addition to the water-soluble resin described above. For the purpose of the receiving layer softening aid at the time, a wax component is added to further improve the releasability from the fixing roller, and the toner particles fixed on the light transmitting recording material are buried in the receiving layer, It is preferable to reduce the granularity of the toner.

Examples of the wax component capable of imparting such properties include carnauba wax, candelilla wax, plant wax such as rice wax and wood wax, mineral wax such as ceresin wax and montan wax, and derivatives thereof. (Examples of montan wax derivatives include acid waxes, ester waxes and partially saponified ester waxes, etc.), animal waxes such as beeswax, spermaceti and lanolin and derivatives thereof, paraffin wax and microcrystalline wax. And synthetic waxes such as polyethylene wax and Fischer-Tropsch wax. In addition, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid and behenic acid, higher alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of sucrose, esters such as fatty acid esters of sorbitan, and amides such as oleylamide It is also possible to use them together.

The amount of the wax component used for forming the toner receiving layer B slightly varies depending on the thickness of the toner receiving layer B, but it is 0.01% to 0.01% based on the total amount of the toner receiving layer B.
30%, preferably in the range of 0.1% to 30%.
If the amount of the releasing agent is less than 0.01%, the releasing effect is insufficient, and if it is more than 30%, transparency is impaired, which is not preferable.

The optimum thickness of the toner receiving layer B varies depending on the particle size of the toner to be fixed.
μm, preferably 3 to 15 μm. The optimum thickness of the toner receiving layer B is also limited by the light transmitting property and the image blur, but since the toner receiving layer is flexible, there is no fear that the image is cracked even if the thickness is increased. .

The toner receiving layer B made of the above constituent materials has a surface resistivity of 10 ¹⁶ Ω /
□ Because of the high level, the antistatic agent is mixed in the toner receiving layer B or coated on the toner receiving layer B, or the conductive undercoat layer C is formed as shown in FIG. It is preferable to adjust the density to 10 ⁷ to 10 ¹³ Ω / □, which is an area suitable for transferring the toner. The measurement of the surface resistivity is based on JIS K
Measured according to 6911. In the present invention, R8340A and R12702A manufactured by Advantest Co., Ltd. were used and measured at 20 ° C., 60% RH, and 100 V.

As the antistatic agent used when mixing or applying the antistatic agent in the toner receiving layer B, any conventionally known antistatic agent can be used. Ammonium salt compounds, pyridinium salt compounds, phosphonium salt compounds, alkyl betaine compounds, alkyl imidazoline compounds, alkyl alanine compounds, polyoxyethylene-type nonionic compounds, polyhydric alcohol-type nonionic compounds, polyvinylbenzyl Conductive cations and polyacrylic acid cations, and ultrafine metal oxide particles such as SnO ₂ and SnO ₂ —Sb dispersed in a binder resin. These antistatic agents may be mixed into a coating solution at the time of forming the toner receiving layer and coated simultaneously, or after forming the toner receiving layer, a solution obtained by dissolving the above antistatic agent in alcohol or the like may be applied to form an extremely thin layer. It is preferable to form an antistatic layer.

In the case where the conductive undercoat layer C is formed, a metal or a conductive substance of a compound thereof can be used as an antistatic agent. Specific examples include metals such as Sn, Sb, In, Ag, Zn, and Ti and metal oxides thereof, Sn-doped In ₂ O ₃ , S
A metal compound such as b-doped SnO ₂ can be used.

Examples of the form of the conductive undercoat layer C include those in which ultrafine particles of these metal oxides, fibers and the like are dispersed together with a binder resin such as polyester and acrylic.

The average particle diameter of the ultrafine metal oxide particles is preferably 0.3 μm or less in order to suppress light scattering.

In the present invention, the conductive undercoat layer C is adjusted to the following resistance range, and even if there is a slight haze as it is, since the haze is further reduced by covering with the toner receiving layer B, the light transmitting property is reduced. Can be set to a level that does not cause a problem in actual use.

In the present invention, the conductive undercoat layer C formed on the light-transmitting substrate has a surface resistance of 10 ⁷ to 10 ¹⁰ Ω.
/ □, preferably 10 ⁷ to 10 ⁹ Ω / □. Surface resistance value is 10 ⁷
Below Ω / □, the coating amount of the above metal or its compound increases, the haze of the conductive undercoat layer increases, the light transmittance decreases, and the toner receiving layer is coated thereon. However, it is not preferable because it is difficult to bring light transmittance to a practical level. If the conductive undercoat layer exceeds 10 ¹⁰ Ω / □, the coating must be very thin to adjust to the above-mentioned area suitable for toner transfer, and is suitable for substantially burying the toner. It is not preferable because the thickness cannot be reduced and the image quality deteriorates.

The light-transmissive recording material for electrophotography of the present invention comprising the above constituent materials is required to have excellent transparency, and has a light transmittance of at least 80 as a total light transmittance as an OHP sheet. % Or more, preferably 85% or more, and the haze is at least 10 or less, preferably 7 or less, more preferably 3 or less. still,
The measurement of transparency in the present invention is performed according to JIS K-7105.
Performed according to.

Next, a fixing device suitable for the present invention will be described. FIG. 2 is a schematic view of an example of a heating roller type fixing device.

The apparatus of this embodiment has a cylindrical heating roller 101 having a heating means such as a heater 101a inside, and rotates clockwise for fixing.

Reference numeral 102 denotes a pressure roller serving as a pressure rotating body having a cylindrical shape.
1 and rotates counterclockwise.

The recording material P, which is transported from the right by the transport belt 103 and has the unfixed toner T adhered as a toner image, is pressed and heated by the heating roller 101 and the pressure roller 102 to be fixed by pressing and heating to the left. Is discharged.

Reference numerals 104a and 104b denote separation claws used for separation in order to prevent the recording material P from being wound around the heating roller 101 or the pressure roller 102 and causing a conveyance failure.

Reference numeral 106 denotes a felt-like oil pad impregnated with a release agent such as silicone oil having appropriate viscosity, and reference numeral 105 denotes a cleaning roller in which brush fibers are implanted in a cylindrical shape. The cleaning roller 105 rotates to remove toner residue adhering to the peripheral surface of the heating roller, and to appropriately supply a release agent. 106 may be omitted.

The heating roller 101 has, for example, a thickness of 2
An Al pipe of about 5 mm is used as a core metal, and 200 to 5
A silicone rubber coated with a thickness of 00 μm or a fluororesin such as tetrafluoroethylene resin (PTFE), perfluoroalkoxy fluororesin (PFA), or fluoroethylene-propylene copolymer (FEP) is used.

As the pressure roller 102, for example, about 10
SUS of mmφ is used as a core metal, and its peripheral surface is coated with silicone rubber to a thickness of about 3 mm.

On the other hand, the heating device of the film heating system is a heating device such as a heat roller system, a hot plate system, a belt heating system, a flash heating system, an open heating system, or an image heating fixing device which is known as another heating system. In comparison with the above, there are the following advantages and they are effective.

(1) In the film heating type heating device,
As the heating element, a low-heat-capacity linear heating element with a low heat capacity made of a film-like thin film can be used, thus saving power and shortening the wait time (quick start property).
And the temperature rise in the apparatus can be suppressed.

(2) In the heating device of the film heating type, the fixing point and the separation point can be set separately, so that the offset can be effectively prevented. In addition, various disadvantages of other system devices can be solved.

FIG. 3 is a schematic diagram of a film heating and fixing type heating device (image heating and fixing device) having the above characteristics.

In FIG. 3, reference numeral 203 denotes a heating member (ceramic heater) fixed to a support, and a heat-resistant film (fixing film) 201 is closely adhered to the heating member 203 by a pressing roller 202 as a pressing rotating member. And transported. Then, the heat-resistant film 201 and the pressure roller 202 in the press-contact nip portion (fixing nip portion) N formed by the heating element 203 and the heating roller 202 with the heat-resistant film 201 interposed therebetween.
Recording material P on which an image is to be fixed as the material to be heated
And the heating element 20 is conveyed while sandwiching the press-contact nip N with the heat-resistant film 201.
The heat of No. 3 is applied to the surface of the recording material P via the heat-resistant film 201, and the unfixed image (toner image) T on the recording material P is heated and fixed on the surface of the recording material P. The recording material P that has passed through the pressure nip N is separated from the surface of the film 201 and transported to the left in the drawing. Heat resistant film 2
Reference numeral 204 denotes a felt-shaped pad which is in contact with 01. In the apparatus shown in FIG. 3, oil is separately supplied to the heat-resistant film 201 by the pad 204.

In the present invention, in the image fixing apparatus having the above configuration, it is preferable not to separately supply a release agent such as silicone oil from the viewpoint of preventing the recording material after fixing from sticking. However, if the amount of the release agent is such that stickiness of the recording material after fixing is not a problem,
It is also possible to heat and fix while supplying a release agent to a fixing portion between the fixing means and the unfixed toner image on the recording material. Specifically, the supply of the release agent is performed by a coating member such as an oil pad (not shown) on the surface of the fixing roller 2 in the heating device shown in FIG.
This is carried out by impregnating a coating member such as an oil pad indicated by 4 with a release agent such as silicone oil. Further, the amount of the release agent separately supplied to the fixing unit is preferably 0.04 mg / sheet (A4 size) or less, more preferably 0.04 mg / sheet (A4 size). It is preferable that the amount is not more than 02 mg / sheet (A4 size).

The fixing method of the present invention as described above is applied to a copying machine,
The present invention can be applied to a fixing device of an image forming apparatus that forms an image using a toner such as a printer and a facsimile.

Hereinafter, the present invention will be specifically described based on examples.

[0066]

【Example】

(Production of polymer solution a) 335 parts by weight of water, 0.8 parts by weight of potassium persulfate, monomer mixture A (methacrylic acid 23
% By weight, 67% by weight of methyl methacrylate, 10% by weight of butyl acrylate) in a reaction vessel at 78 ° C.
The reaction was performed for 0 min. Subsequently, 90 parts by weight of the monomer mixture A was continuously charged for 2 hours, and further reacted at 78 ° C. for 3 hours. The obtained polymer solution was neutralized with 14% aqueous ammonia to obtain a polymer solution a shown in Table 1.

(Production of polymer solution b) 300 parts by weight of water,
0.8 parts by weight of potassium persulfate, monomer mixture B (31% by weight of methacrylic acid, 59% by weight of methyl methacrylate,
10 parts by weight of butyl acrylate (10% by weight) were reacted in a reaction vessel at 78 ° C. for 30 minutes. Subsequently, 90 parts by weight of the monomer mixture B was continuously charged for 2 hours, and further reacted at 78 ° C. for 3 hours. The obtained polymer solution was
Neutralized with 4% aqueous ammonia to obtain a polymer solution b shown in Table 1.

(Production of polymer solution c) 200 parts by weight of water,
0.8 parts by weight of potassium persulfate, monomer mixture C (36% by weight of methacrylic acid, 49% by weight of methyl methacrylate,
10 parts by weight of butyl acrylate (15% by weight) and 0.01 part by weight of lauryl mercaptan were placed in a reaction vessel at 78 ° C for 3 hours.
The reaction was performed for 0 min. Subsequently, 90 parts by weight of the monomer mixture C and 0.09 parts by weight of lauryl mercaptan were continuously charged for 2 hours, and further reacted at 78 ° C. for 3 hours.
The obtained polymer solution was neutralized with 14% aqueous ammonia to obtain a polymer solution c shown in Table 1.

(Production of polymer solution d) 300 parts by weight of water,
0.8 parts by weight of potassium persulfate, monomer mixture F (27% by weight of methacrylic acid, 63% by weight of methyl methacrylate,
10 parts by weight of butyl acrylate (10% by weight) were reacted in a reaction vessel at 78 ° C. for 30 minutes. Subsequently, 90 parts by weight of the monomer mixture F was continuously charged for 2 hours, and further reacted at 78 ° C. for 3 hours. The obtained polymer solution was
The solution was neutralized with 4% aqueous ammonia to obtain a polymer solution d shown in Table 1.

(Production of polymer solution e) 335 parts by weight of water,
0.8 parts by weight of potassium persulfate, 10 parts by weight of monomer mixture D (40% by weight of acrylic acid, 20% by weight of styrene, 40% by weight of α-methylstyrene), and 0.01 part by weight of lauryl mercaptan were placed in a reaction vessel at 78 ° C. For 30 minutes. Subsequently, a mixture consisting of 90 parts by weight of the monomer mixture D and 0.09 parts by weight of lauryl mercaptan was continuously charged for 2 hours, and further reacted at 78 ° C. for 3 hours. The obtained polymer solution was neutralized with 14% aqueous ammonia to obtain a polymer solution e shown in Table 1.

(Production of polymer solution f) 300 parts by weight of water,
0.8 parts by weight of potassium persulfate, monomer mixture A 10
Parts by weight and 0.01 parts by weight of lauryl mercaptan were reacted in a reaction vessel at 78 ° C. for 30 minutes. Subsequently, 90 parts by weight of monomer mixture A and lauryl mercaptan 0.0
The mixture consisting of 9 parts by weight was charged continuously for 2 hours, and further reacted at 78 ° C. for 3 hours. The obtained polymer solution was neutralized with 14% aqueous ammonia to obtain a polymer solution f shown in Table 1.

(Production of polymer solution g) 335 parts by weight of water,
0.8 parts by weight of potassium persulfate, monomer mixture E (23% by weight of methacrylic acid, 77% by weight of methyl methacrylate)
10 parts by weight were reacted at 78 ° C. for 30 minutes in a reaction vessel. Subsequently, 90 parts by weight of the monomer mixture E was continuously charged for 2 hours, and further reacted at 78 ° C. for 3 hours. The obtained polymer solution was neutralized with 14% aqueous ammonia to obtain a polymer solution g shown in Table 1.

(Production of polymer solution h) 335 parts by weight of water,
0.6 parts by weight of potassium persulfate, monomer mixture B 10
The parts by weight were reacted in a reaction vessel at 72 ° C. for 30 minutes.
Subsequently, 90 parts by weight of the monomer mixture B was continuously charged for 2 hours, and further reacted at 72 ° C. for 4 hours. The obtained polymer solution was neutralized with 14% ammonia water to obtain a polymer solution h shown in Table 1.

(Production of polymer solution i) 300 parts by weight of water
0.5 parts by weight of potassium persulfate, monomer mixture A 10
The parts by weight were reacted in a reaction vessel at 72 ° C. for 30 minutes.
Subsequently, 90 parts by weight of the monomer mixture A was continuously charged for 3 hours, and further reacted at 72 ° C. for 4 hours. The obtained polymer solution was neutralized with 14% aqueous ammonia to obtain a polymer solution i shown in Table 1.

(Production of polymer solution j) 300 parts by weight of water,
0.8 parts by weight of potassium persulfate, monomer mixture F (27% by weight of methacrylic acid, 63% by weight of methyl methacrylate,
10 parts by weight of butyl acrylate) and 0.01 parts by weight of lauryl mercaptan in a reaction vessel at 78 ° C.
min. Subsequently, a mixture consisting of 90 parts by weight of the monomer mixture F and 0.09 parts by weight of lauryl mercaptan was continuously charged for 2 hours, and further reacted at 78 ° C. for 3 hours. The obtained polymer solution was neutralized with 14% aqueous ammonia to obtain a polymer solution j shown in Table 1.

Example 1 Sb-doped SnO ₂ ultrafine particles (average particle size of secondary particles 0.2 μm) as a conductive undercoat layer on a transparent substrate made of PET having a thickness of about 100 μm
Solution containing 4% solids dispersed therein (coating liquid 1 for undercoat layer)
Is applied and dried, and the surface resistance of the conductive undercoat layer is reduced to about 10 ^8.
Adjusted to Ω / □. A polymer solution a was applied to the surface by a bar coating method using a wire bar,
Dry at 4 ℃ for 4 minutes, dry thickness about 5μm, surface resistance value 10
An electrophotographic OHP sheet A of ¹¹ Ω / □ was obtained.

<Examples 2 to 4> OHP sheets B to D for electrophotography were obtained in the same manner as in Example 1 except that the polymer solution was changed as shown in Table 1.

<Example 5> Except that 2% by weight of a phosphoric acid ester wax was added to the polymer solution a at a solid content ratio,
An OHP sheet E for electrophotography was obtained in the same manner as in Example 1.

Comparative Examples 1 to 6 Electrophotographic OHP sheets F to K were obtained in the same manner as in Example 1 except that the polymer solution was changed as shown in Table 1.

The OHP for electrophotography thus obtained
The toner images were formed on the sheets A to K by the following method and evaluated. Table 1 shows the evaluation results of the obtained electrophotographic OHP sheets A to K.

(1) Evaluation of Image Production of Yellow Toner 100 parts by weight of styrene-butyl acrylate-divinylbenzene copolymer 5 parts by weight of polyolefin wax (melting point 100 ° C.) I. Pigment Yellow 17 4.5 parts by weight Di-tert-butylsalicylic acid metal oxide 3 parts by weight After mixing the above materials, melt-kneading with a biaxial kneading extruder, then cooling, pulverizing with an air-flow type pulverizer, and air classification The powder was classified by a mixer to obtain a yellow powder toner having a weight average diameter of about 8.5 μm. 0.8 part by weight of negatively chargeable colloidal silica was externally added to 100 parts by weight of this toner to obtain a yellow toner.

[0082] For the yellow toner 100 parts by weight obtained in the image reproduction above,
0.7 parts by weight of hydrophobic silica having a specific surface area of 200 m ² / g by the BET method was externally added. To 7 parts by weight of this toner, 93 parts by weight of a Cu-Zn-Fe-based ferrite carrier surface-coated with a styrene-methyl methacrylate copolymer were mixed to prepare a two-component developer.

Using this two-component developer, an OHP sheet was used as a recording material in a modified full-color copier (CLC-500, manufactured by Canon Inc.) under the environment of 23 ° C./65% RH. The image is developed at a development contrast of 320 V, a yellow toner image is transferred onto an OHP sheet, and the unfixed yellow toner image is transferred to an external fixing device (a commercially available CL).
Same roller configuration as C-500, no oil application function)
Fixing temperature 170 ° C, Fixing speed 30mm / sec
Was established.

Evaluation of image properties Each of the obtained light-transmissive recording materials having a yellow color image is projected on a screen by an OHP, and the color tone reproducibility of the intermediate image density portion is excellent by visual sensory evaluation.か ら, △, and × in that order. The evaluation criteria are as follows. ：: Good color reproducibility without gray in the intermediate image density portion. Δ: The intermediate image density portion is slightly grayish and the color tone is orange. ×: The intermediate image density portion is grayish.

Here, the intermediate image density portion is obtained by converting the obtained yellow toner image into a Macbeth reflection densitometer RD-1255.
Indicates a portion where the yellow density measured on Xerox 4024 DP Paper is in the range of 0.2 to 1.5.

(2) Releasability from Fixing Roller An external fixing machine (with the same roller configuration as a commercially available CLC-500, without an oil application function) was used to fix the fixing temperature to 170 ° C.
Under the conditions of a fixing speed of 30 mm / sec, the produced OHP sheet was evaluated according to the following criteria without forming a toner image. A: The sheet passed without sticking to the fixing roller. ：: The first part of the sheet slightly adhered to the fixing roller, but passed without any problem by using the separation claw pressed against the roller with a pressure of about 10 gf. X: The sheet stuck to the fixing roller even when the separation claw pressed against the roller with a pressure of about 10 gf was used.

[0087]

[Table 1]

Production of Magenta Toner C.I. I. Pigment Yellow 17 and C.I. I. A magenta toner was produced in the same manner as in the production of the yellow toner, except that Pigment 122 was used.

Production of Cyan Toner C.I. I. Pigment Yellow 17 and C.I. I. A cyan toner was produced in the same manner as in the production of the yellow toner, except that Pigment Blue 15 was used.

Production of Black Toner C.I. I. A black toner was produced in the same manner as in the production of the yellow toner, except that Pigment Yellow 17 was replaced with a commercially available carbon black.

<Examples 6 to 10> Each of the above magenta toner, cyan toner and black toner was mixed with an external addition of hydrophobic silica and a ferrite carrier in the same manner as the two-component developer using the yellow toner. Two-component developers of three colors of magenta, cyan and black were respectively prepared.

A four-color two-component developer obtained by adding a two-component developer of yellow to a two-component developer of three colors of magenta, cyan, and black was used, and a commercially available full-color copying machine (CLC-500, Using a remodeling machine manufactured by Canon Inc., and using an OHP sheet as a recording material, development was performed at a development contrast of 320 V in an environment of a temperature of 23 ° C. and a humidity of 65% RH, and a full-color image was transferred onto the OHP sheet. The full-color image of the image is transferred to an external fixing device (commercial CLC-
The fixing was performed at a fixing temperature of 170 ° C. and a fixing speed of 30 mm / sec.

When the OHP sheets A to E used in Examples 1 to 5 were used as the recording material, the toner did not offset at the time of fixing, and the OHP sheet did not stick to the fixing roller. Further, when the obtained OHP sheet having a full-color image was projected on a screen by OHP, a very clear full-color projected image was obtained in which the intermediate image density portion was not grayed.

In particular, when the OHP sheet E used in Example 5 was used, compared with the case where the OHP sheet A used in Example 1 was used, a softening aid for the phosphate ester wax receiving layer was used. As a result, the color tone reproducibility of the mixed color portion was excellent.

[0095]

As described above, according to the present invention, when used in an overhead projector (OHP), a projected image, particularly an intermediate tone having a low image density, does not stick to the surface of the fixing means at the time of fixing. Provided are a light-transmitting recording material for electrophotography capable of obtaining a color image or a full-color image having good color tone reproducibility without grayishness in a part, and a method for heat-fixing a toner image.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a light-transmitting recording material for electrophotography according to the present invention.

FIG. 2 shows heat fixing means that can be used in the heat fixing method of the present invention.

FIG. 3 shows another example of the heat fixing means that can be used in the heat fixing method of the present invention.

[Explanation of symbols]

 Reference Signs List A light-transmitting substrate (base film) B toner receiving layer P recording material T toner 101 heating roller 102 pressure roller 201 heat-resistant film 202 pressure roller 203 heating element 204 oil pad

Claims (8)

[Claims] 1. An electrophotographic light-transmitting recording material having at least a light-transmitting substrate and a toner-receiving layer mainly formed of a water-soluble resin formed on the substrate, wherein the water-soluble resin has an acid value of 120 to 164, a weight average molecular weight (Mw) of 10,000 to 15,000, and a glass transition point (Tg) of 77 to 95 ° C. Recording material. 2. The light-transmitting recording material for electrophotography according to claim 1, wherein the water-soluble resin comprises a methacrylic acid-based resin or an acrylic acid-based resin. 3. The light-transmissive recording material for electrophotography according to claim 1, wherein the toner receiving layer contains a wax component. 4. A heat fixing method for fixing a toner image formed on a light transmitting recording material onto the light transmitting recording material by the action of heat and pressure of a heat fixing means, wherein the light transmitting recording material is fixed. The material has at least a light-transmitting substrate and a toner receiving layer mainly composed of a water-soluble resin formed on the substrate,
The water-soluble resin has an acid value in the range of 120 to 164,
A heat fixing method, wherein the weight average molecular weight (Mw) is in the range of 10,000 to 15000, and the glass transition point (Tg) is in the range of 77 to 95 ° C. 5. The heat fixing method according to claim 4, wherein the water-soluble resin includes a methacrylic resin or an acrylic resin. 6. The heat fixing method according to claim 4, wherein the toner receiving layer contains a wax component. 7. The heat fixing method according to claim 4, wherein a heat fixing means which does not separately supply oil is used as the heat fixing means. 8. The heat fixing means is a fixing means using oil separately, and the surface of the light transmitting recording material is coated with 0.04 mg of oil per sheet (A4 size) by the heat fixing means.
The heat fixing method according to any one of claims 4 to 6, wherein the composition is applied in the following amount.