JP2005115119A - Electrophotographic label sheet and image forming method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin-film based electrophotographic label sheet that can transfer toner more uniformly than a conventional label sheet, is free of generation of a holocharacter etc., and has good toner fixing property after fixation, and an image forming method. <P>SOLUTION: The electrophotographic label sheet has a toner receiving layer, containing metal oxide, formed on the surface of a label base material on the opposite side from a surface where a sticky layer is provided, and is characterized in that the surface resistivity of the toner receiving layer is 1×10<SP>13</SP>to 5×10<SP>14</SP>Ω/sq. when a voltage of 100 V is applied and 1×10<SP>9</SP>to 1×10<SP>12</SP>Ω/sq. when a voltage of 1,000 V is applied and the surface resistivity of the surface of a separator on the opposite side from a surface temporarily bonded to the label body is 1×10<SP>10</SP>to 1×10<SP>13</SP>Ω/sq. when the voltage of 1,000 V is applied. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic label sheet used in an indirect dry electrophotographic copying machine and printer, and an image forming method using the same.

  With the colorization and digitization of electrophotographic copying machines and printers, higher image quality and higher speed of electrophotographic methods have been studied. In particular, in electrophotographic full-color copiers and printers, in order to support high-quality images and high speed, digital input / output of images has progressed, and image input methods, input image processing methods, development methods, The transfer method and fixing method have been greatly improved. Also, image forming materials for developers and photoreceptors have been improved in response to digital high definition and high color development color recording.

  On the other hand, with the improvement in image quality of full-color copiers and printers, not only high-quality paper but also various types of media such as coated paper, cast-coated paper, plastic material, and sealing material with high basis weight are used as recording media. It is coming. In particular, various applications for photography have been proposed for seals and label materials. However, label paper (label sheet) using a thick plastic material or resin film as a base is difficult to improve the transferability of the toner. In particular, the toner cannot be uniformly and uniformly transferred. A state in which the toner in the center of the image is removed (hereinafter referred to as “holo character”) is likely to occur.

  In order to improve the toner transferability of a label sheet made of a resin film, the surface transfer resistance of the label sheet is controlled by a surfactant to improve the toner transferability (see, for example, Patent Documents 1 to 4). However, when the surfactant is used in the toner receiving layer, the adhesion force of the toner is reduced and the holocharacter is likely to be generated. Further, the fixing property of the toner after fixing is deteriorated, and there is a problem that when the toner is bent, the toner is easily peeled off from the resin film.

Further, the surface resistance value of the label sheet is controlled to 10 ⁶ to 10 ¹³ Ω with a metal oxide, and attempts have been made to achieve both toner transfer properties and toner fixing properties (see, for example, Patent Documents 5 to 7). However, although the toner fixing property can be improved, there remains a problem that the holocharacter is not improved.

Furthermore, in order to improve the holocharacter on the OHP film, an attempt is made to uniformly roughen the ten-point average roughness (Rz) of the toner receiving layer surface to a range of 0.1 to 10 μm (see, for example, Patent Document 8). ). However, it is difficult to improve the holocharacter only by increasing the surface roughness of the toner receiving layer surface.
JP 2000-250248 A JP-A-6-337537 JP-A-6-332222 JP-A-6-095420 JP-A-6-301231 JP-A-6-301230 JP-A-6-301229 Japanese Patent Laid-Open No. 7-248637

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, the present invention can transfer the toner uniformly and non-uniformly compared to the conventional label sheet, does not generate a holo character, and has a good toner fixing property after fixing. It is intended to provide a label sheet and an image forming method.

  In order to improve the above-described problems, the present inventors have developed a toner receiving layer and a back surface (surface opposite to the surface temporarily bonded to the label body of the separator) of the electrophotographic label sheet comprising a resin film base. The inventors studied diligently the resistivity control method, the conductive material, and the surface roughness of the toner receiving layer. As a result, in order to improve toner transferability, it is necessary to add a conductive agent capable of controlling the surface resistivity to the toner-receiving layer to reduce the surface resistivity. However, if a surfactant is added as a conductive agent, It has been found that there is a problem that a holo-character is easily generated and toner after fixing is easily peeled off.

Therefore, an attempt was made to improve the holocharacter and the toner fixability by adding a conductive metal oxide without using a surfactant as a conductive agent in the toner receiving layer. However, when a conductive metal oxide is used, it is difficult to adjust the surface resistivity. If too much conductive metal oxide is added, sufficient toner transferability cannot be obtained, and holocharacters are likely to occur. End up. On the other hand, if the amount is decreased, the antistatic effect is eliminated, and sufficient toner transferability cannot be obtained, and holocharacters are generated. In particular, the surface resistivity of the toner receiving layer under the measurement condition of the applied voltage of 100 V is 1 × 10 ^13. It has been found that if it is less than Ω / □, toner transferability and holocharacter generation cannot be improved. When a conductive metal oxide is used, toner transferability and holocharacter generation occur at a surface resistivity of 1 × 10 ¹³ Ω / □ or more at an applied voltage of 100 V, which is a region where the transfer latitude is narrow. It was confirmed that there is an area that can be improved.

Further investigation has been conducted, and when a conductive metal oxide is added, the surface resistivity is high under an applied voltage of 100 V, but there is a prescription that the surface resistivity decreases under an applied voltage of 1000 V. The surface resistivity of the toner receiving layer at an applied voltage of 100 V is kept within a range of 1 × 10 ^{13 to} 5 × 10 ¹⁴ Ω / □ and the surface resistance at an applied voltage of 1000 V is kept within a certain range. When a toner receiving layer that reduces the rate to the range of 1 × 10 ⁹ to 1 × 10 ¹² Ω / □ is formed, stable toner transfer and holocharacter improvement can be obtained, and toner fixability after fixing can also be improved. As a result, the present invention has been completed.

That is, the present invention
<1> A label body having a pressure-sensitive adhesive layer provided on one side of a label base material, and a separator temporarily bonded to the label body through the pressure-sensitive adhesive layer. The label base material and the separator base It is an electrophotographic label sheet in which the material is a heat-resistant resin film,
A toner receiving layer containing a metal oxide is formed on the surface of the label substrate opposite to the surface on which the adhesive layer is provided, and the surface resistivity of the toner receiving layer at an applied voltage of 100 V is 1 × 10. ^{It is in} the range of ^{13 to} 5 × 10 ¹⁴ Ω / □, the surface resistivity at an applied voltage of 1000 V is in the range of 1 × 10 ⁹ to 1 × 10 ¹² Ω / □, and is temporarily bonded to the label body of the separator. The electrophotographic label sheet is characterized in that the surface resistivity at an applied voltage of 1000 V on the surface opposite to the surface is 1 × 10 ¹⁰ to 1 × 10 ¹³ Ω / □.

<2> The electrophotographic label sheet according to <1>, wherein the metal oxide is needle-like TiO ₂ coated with SnO ₂ doped with Sb.

<3> The major axis length of the needle-like TiO ₂ particles coated with SnO ₂ doped with Sb is in the range of 2.5 to 6 μm, and the aspect ratio is in the range of 10 to 30. <2> The electrophotographic label sheet according to <2>.

<4> The electrophotographic label sheet according to any one of <1> to <3>, wherein a ten-point average roughness Rz of the surface of the toner receiving layer is in the range of 5 to 15 μm. .

<5> As a recording medium, an electrophotographic label sheet composed of a label body and a separator temporarily bonded to the label body via an adhesive layer is used, and at least a toner image is formed on the surface of the toner receiving layer of the label body. An image forming method comprising: a transfer step of transferring the toner image; and a fixing step of heating and melting the toner image by a fixing device and fixing the toner image to the toner receiving layer,
An electrophotographic label sheet according to any one of <1> to <4> is used as the electrophotographic label sheet.

  According to the present invention, the label body and the separator are made of a heat-resistant resin film, and a conductive metal oxide is added to the toner receiving layer so that the surface resistivity of the toner receiving layer surface and the back surface falls within an appropriate range. Thus, it is possible to provide an electrophotographic label sheet having good toner transfer property, holocharacter suppression property, and toner fixing property, and an image forming method using the same.

  Hereinafter, the present invention will be described in detail by dividing it into an electrophotographic label sheet (hereinafter sometimes simply referred to as “label sheet”) and an image forming method.

<Electrophotographic label sheet>
The electrophotographic label sheet of the present invention is composed of a label body provided with an adhesive layer on one side of a label substrate, and a separator temporarily bonded to the label body through the adhesive layer, The label base material and the separator base material are both electrophotographic label sheets which are heat-resistant resin films, and include a metal oxide on the surface of the label base material opposite to the surface on which the adhesive layer is provided. A toner receiving layer is formed, and the surface resistivity of the surface of the label body on the side on which the toner receiving layer is formed is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁴ Ω / □ at an applied voltage of 100 V. Surface resistivity at 1000 V in the range of 1 × 10 ⁹ to 1 × 10 ¹² Ω / □, and the surface of the separator opposite to the surface temporarily bonded to the label body at an applied voltage of 1000 V resistivity, 1 × ¹⁰ 10 ~ Characterized in that it is a × 10 ¹³ Ω / □ range.

That is, the surface resistivity of the surface of the label body on which the toner receiving layer is formed (the surface on which toner is transferred) at an applied voltage of 100 V is in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁴ Ω / □. By doing so, it is possible to suppress the generation of holocharacters and to ensure the toner transferability to a certain level or more. Further, since no surfactant is used for the resistance adjustment, the fixing property of the toner to the toner receiving layer does not deteriorate.

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of the electrophotographic label sheet of the present invention.
In FIG. 1, an electrophotographic label sheet of the present invention comprises a label base material 54, an anchor coat layer 53 provided on one side of the label base material 54, a toner receiving layer 52 provided on the surface of the anchor coat layer 53, A label body 50 including an adhesive layer 55 provided on the surface opposite to the toner receiving layer 52 provided on one side of the label base material 54, and the label body 50 are detachably adhered via the adhesive layer 55. Separator 60. The separator 60 includes a separator base 64, a release layer 63 provided on the surface of the separator base 64 in contact with the adhesive layer 55, and a charging provided on a surface opposite to the release layer 63 of the separator base 64. It consists of a prevention treatment layer 65.

  In the present invention, the label substrate 54 is made of a heat resistant resin film, and specific examples of the heat resistant resin film include plastic materials such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polypropylene, polyimide, and polystyrene. Moreover, in order to suppress the shrinkage at the time of heating and to adjust the whiteness, it is preferable to add a filler such as titanium dioxide or calcium carbonate to these resins.

  The thickness of the label substrate 54 is preferably in the range of 25 to 150 μm, and more preferably in the range of 40 to 100 μm. If the thickness is less than 25 μm, it may be difficult to handle as a label, and if the thickness is more than 150 μm, transfer / fixing performance in a printer and a copying machine may be deteriorated. Further, as the label base material 54, it is preferable to use a plastic material which has been heat-treated in advance and thermally contracted.

  The toner receiving layer 52 is not only a toner receiving layer but also an antistatic control layer. A thermoplastic resin is used for the toner receiving layer 52. Examples of the thermoplastic resin include polystyrene resin, styrene-vinyl acetate resin, acrylic resin, styrene-acrylate resin, styrene-methacrylate resin, and polyurethane resin. And polyester resins.

  The thickness of the toner receiving layer 52 is preferably in the range of 0.5 to 15 μm. If the thickness is less than 0.5 μm, a metal oxide as a conductive agent, which will be described later, is easily peeled off from the toner receiving layer 52, and as a result, sufficient transferability cannot be obtained. On the other hand, if the thickness exceeds 15 μm, a toner offset phenomenon that the thermoplastic resin of the toner receiving layer 52 easily adheres to the fixing device (fixing device) at the time of heat-fixing, and winding of the label sheet around the fixing device occurs. It becomes easy. Further, the toner receiving layer 52 may be peeled off or cracked. However, the thickness of the toner receiving layer 52 needs to be in the range of 2 to 15 μm in order to develop high gloss and uniform image gloss.

  The storage elastic modulus of the thermoplastic resin used for the toner receiving layer 52 is desirably in the range of 4 to 15000 Pa at 130 ° C. If the pressure is lower than 4 Pa, the thermoplastic resin becomes too soft during heat fixing and tends to adhere to the fixing device, so that toner offset phenomenon and winding around the fixing device are likely to occur. If it exceeds 15000 Pa, the toner fixability deteriorates, which is not preferable. However, in order to develop a high gloss and uniform image gloss, the storage elastic modulus of the toner receiving layer 52 is preferably in the range of 4 to 250 Pa, and more preferably in the range of 4 to 100 Pa. When the storage elastic modulus is higher than 250 Pa, the toner embedding property in the toner receiving layer 52 is deteriorated, and the image gloss uniformity is deteriorated.

  The storage elastic modulus was measured using a dynamic analyzer RDAII manufactured by Rheometrics under the condition of a measurement frequency of 10 rad / s.

  The Tg (glass transition temperature) of the thermoplastic resin used for the toner receiving layer 52 is preferably in the range of 50 to 90 ° C. If the Tg is less than 50 ° C., the label sheet may become sticky when exposed to high temperatures, and in the worst case, the label sheet may adhere to other materials or between the label sheets. On the other hand, if Tg exceeds 90 ° C., the melting of the resin in the fixing device becomes poor and the gloss uniformity may be inferior.

  The toner receiving layer 52 may contain a release agent in order to have a release performance. Examples of the mold release agent include carnauba wax, rice wax, candelilla wax, paraffin wax, and olefin wax. By adding the release agent, the releasability to the fixing device is enhanced, so that winding around the fixing device is reduced. Since the release effect varies depending on the type of release agent, the addition amount may be adjusted depending on the type of release agent.

  The content of the release agent is preferably in the range of 1 to 10% by mass with respect to the entire toner receiving layer. When the content exceeds 10% by mass, the glossiness of the image is lowered and gloss unevenness may easily occur. If the content is less than 1% by mass, the effect of reducing the fixing device wrapping may be low.

  The melting point of the release agent is preferably in the range of 50 to 90 ° C. When the melting point of the release agent exceeds 90 ° C, the release agent melts poorly in the fixing device, and the label sheet is easily wrapped around the fixing device or the gloss uniformity is poor. There is. Further, if the melting point of the release agent is less than 50 ° C., the label sheet may become sticky and uneven gloss may occur when exposed to a high temperature.

The surface resistivity of the toner receiving layer 52 needs to be in the range of 1 × 10 ^{13 to} 5 × 10 ¹⁴ Ω / □ at an applied voltage of 100 V, and in the range of 1 × 10 ⁹ to 1 × 10 ¹² Ω / □ at an applied voltage of 1000 V. There is. When the applied voltage is 100 V, the range is preferably 1 × 10 ¹³ to 1 × 10 ¹⁴ Ω / □, and when the applied voltage is 1000 V, the range is preferably 5 × 10 ^{9 to} 5 × 10 ¹¹ Ω / □. A range of ⁹ to 1 × 10 ¹¹ Ω / □ is more preferable.

If the surface resistivity at an applied voltage of 100 V is less than 1 × 10 ¹³ Ω / □ and the surface resistivity at an applied voltage of 1000 V is lower than 1 × 10 ⁹ Ω / □, a holocharacter is likely to occur as described above. In addition, toner transferability becomes insufficient, and toner transfer unevenness occurs in the surface. In addition, when the surface resistivity at an applied voltage of 100 V is higher than 5 × 10 ¹⁴ Ω / □ and the surface resistivity at an applied voltage of 1000 V is higher than 1 × 10 ¹² Ω / □, the toner transfer amount decreases, so that the toner transferability. Unevenness is likely to occur and holocharacters are likely to occur, which is not preferable.

Examples of the conductive metal oxide added to keep the surface resistivity of the toner receiving layer 52 within the above optimal range include ZnO, TiO, SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO _2. , MgO, BaO, and MoO ₃ . These may be used alone or in combination. Further, the metal oxide preferably further contains a different element, for example, Al, In, etc. with respect to ZnO, Nb, Ta, etc. with respect to TiO, and Sb, Nb with respect to SnO ₂ . Those doped with a halogen element or the like are preferable.

Further, the metal oxide in the present invention includes a composite of the metal oxide. For example, a TiO ₂ particle coated with SnO ₂ doped with Sb may be used.

In the present invention, acicular metal oxides are particularly preferred, and in particular, acicular TiO ₂ particles coated with SnO ₂ doped with Sb, the major axis length being in the range of 2.5 to 6 μm, aspect ratio The ratio is preferably in the range of 10-30, more preferably in the range of 20-30.

  In order to keep the surface resistivity of the toner receiving layer 52 within the optimum range, it is necessary that the conductive metal oxide is uniformly dispersed when the toner receiving layer 52 is formed. In order to obtain this uniform dispersion state, it is necessary to control the coating liquid preparation conditions and the layer formation conditions for forming the toner receiving layer 52.

  As conditions for preparing the coating liquid, first, a dispersant such as a surfactant may be used in order to improve the dispersibility of the metal oxide. As the dispersant, a solvent-based dispersant is used if the coating liquid is solvent-based, and an aqueous dispersant is used if it is water-based. Moreover, it is preferable to disperse | distribute using a stirrer, an ultrasonic wave, etc.

  Further, as a layer forming condition, it is preferable that uniform coating is performed by a bar coater, an air knife coater, a rod blade coater, a blade coater, a comma coater or the like, and the solvent is quickly dried.

  When a large amount of conductive metal oxide is added to the toner receiving layer 52, the surface resistivity is excessively lowered. Conversely, even if the addition amount is small, the surface resistivity increases at 1000 V applied voltage, which is not preferable. The addition amount of the conductive metal oxide needs to be changed depending on the particle diameter of the conductive metal oxide and the thickness of the toner receiving layer 52. In any case, the surface resistivity is within the above optimum range. What is necessary is just to add so that it may fit.

  Specifically, for example, the thickness of the toner receiving layer 52 is preferably about 5 μm, and the addition amount of the metal oxide is preferably in the range of 5 to 20% by mass, and 7 to 15% by mass with respect to the entire toner receiving layer. A range is more preferred.

The surface roughness of the formed toner receiving layer 52 is preferably in the range of 5 to 15 μm, more preferably in the range of 7 to 12 μm in terms of the ten-point average roughness Rz. If Rz is in the range of 5 to 15 μm, holocharacters are hardly generated. If the ten-point average roughness Rz of the toner receiving layer 52 is smaller than 5 μm, the holocharacter tends to deteriorate, and if it exceeds 15 μm, it deteriorates in the same manner.
The ten-point average roughness Rz was measured in accordance with JISB-0601-1994 with a reference length of 0.8 mm.

  In order to set the ten-point average roughness Rz on the surface of the toner receiving layer 52 within the above range, it is controlled by the aspect ratio of the metal oxide and the thickness of the toner receiving layer 52 or, if necessary, plastic fine particles are added. May be. Examples of the plastic fine particles include polymers such as polyethylene, polyvinyl fluoride, polyvinylidene fluoride, and polytrifluoroethylene.

The surface resistivity of the surface of the separator 60 opposite to the surface temporarily bonded to the label body 50 needs to be in the range of 1 × 10 ¹⁰ to 1 × 10 ¹³ Ω / □ at an applied voltage of 1000V. By setting the surface resistivity within the above range, the toner transferability can be improved.

In order to make the surface resistivity of the separator 60 within the above range, an antistatic treatment layer 65 is preferably provided on one side of the separator base 64.
As the conductive treatment of the antistatic treatment layer 65, a thermoplastic resin used for the toner receiving layer 52 with a conductive metal oxide added may be applied, various surfactants may be applied, or thermoplasticity may be applied. A surfactant may be added to the resin and applied.

  In addition, the surface resistivity demonstrated above is measured by the method based on JIS-K-6911 in an environment of 23 degreeC and 50% RH. By using Advantest digital ultra-high resistance meter R8340 and resiliency chamber R12704 (electrode diameter: 50 mm) as the measuring instrument, and measuring the current value after 1 minute when the applied voltage is 100 V and 1000 V went. Each sample was allowed to stand for 24 hours or more in an environment of 23 ° C. and 50% RH, and then subjected to measurement.

  An anchor coat layer 53 is preferably provided between the toner receiving layer 52 and the label substrate 54. The toner receiving layer 52 and the label base material 54 may have low adhesion, and if the anchor coat layer 53 is not provided in such a configuration, the toner receiving layer 52 does not adhere strongly to the label base material 54 and the label When the sheet is deformed, the toner receiving layer 52 may be peeled off from the label base material 54.

  The pressure-sensitive adhesive layer 55 provided on the back surface of the label base 54 with respect to the toner receiving layer 52 can be formed using an acrylic or rubber-based pressure-sensitive adhesive. The coating thickness of the adhesive layer 55 is preferably in the range of 5 to 30 μm, and more preferably in the range of 10 to 20 μm. If the thickness of the adhesive layer 55 is larger than the above range, the adhesive protrudes from the end face of the label sheet, contaminates the inside of the copier / printer, and may cause a paper feed failure. Also, if the thickness of the adhesive layer 55 is less than the above range, the adhesive force is insufficient, and when the label sheet is rubbed inside the copying machine / printer, the separator 60 and the label body 50 peel off, and the inside of the copying machine / printer. This causes sticking to the member and a paper feed failure occurs.

  The separator base material 64 in the present invention is a heat-resistant resin film like the label base material 54. Examples of the heat-resistant resin film include polymer films such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polypropylene, polyimide, polystyrene, or the like. A film in which a filler or the like is blended with a base material can be used. In addition, it is preferable that the said base material has heat resistance even at 100 degreeC or more.

  The thickness of the separator substrate 64 is preferably in the range of 25 to 150 μm, and more preferably in the range of 50 to 100 μm. If the thickness is less than 25 μm, it may be difficult to handle as a label, and if the thickness is more than 150 μm, transfer / fixing performance in a printer and a copying machine may be deteriorated.

  The release layer 63 provided on one side of the separator substrate 64 can be formed by applying an ultraviolet curable silicone resin, a thermosetting silicone resin, or the like. The thickness of these release layers 63 is usually in the range of 0.05 to 1 μm, but is not limited thereto.

<Image forming method>
The image forming method of the present invention is an image forming method using the electrophotographic label sheet of the present invention described above as a recording medium, and at least a transfer step of transferring a toner image to the surface of the toner receiving layer of the label body, And a fixing step in which the toner image is heated and melted by a fixing device and fixed on the toner receiving layer.
The image forming method of the present invention is preferably used for the color image forming method using the color toner exemplified below, but the image forming method of the present invention is not limited to the color image forming method, The present invention is also applied to image formation using monochrome toner.

  FIG. 2 is a schematic configuration diagram showing an example of an image forming apparatus used in the image forming method of the present invention. An image forming apparatus 100 in the figure is a tandem type color image forming apparatus. The image forming apparatus 100 is read by color image information sent from a personal computer or the like (not shown), an image data input device, and an image reading device. Color image information and the like of a color document are input, and image processing is performed on the input image information.

  1Y, 1M, 1C, and 1K are electrophotographic image forming units that form toner images of yellow, magenta, cyan, and black, respectively, and an endless intermediate transfer member 9 that is stretched by a plurality of stretching rolls 10. Are arranged in series in the order of 1Y, 1M, 1C, and 1K. The intermediate transfer member 9 is a transfer means 6Y, 6M, 6C disposed opposite to the electrostatic latent image carriers 2Y, 2M, 2C, 2K of the electrophotographic image forming units 1Y, 1M, 1C, 1K. , 6K is inserted.

The operation of forming an image on the intermediate transfer member 9 will be described using the electrophotographic image forming unit 1Y that forms a yellow toner image as a representative.
First, the surface of the electrostatic latent image carrier 2Y is uniformly charged by the uniform charger 3Y. Next, image exposure corresponding to the yellow image is performed by the exposure device 4Y, and an electrostatic latent image corresponding to the yellow image is formed on the surface of the electrostatic latent image carrier 2Y. The electrostatic latent image corresponding to the yellow image is converted into a yellow toner image by the developing device 5Y, and is transferred onto the intermediate transfer member 9 by the pressing force and electrostatic suction of the primary transfer roll 6Y constituting a part of the primary transfer unit. . The yellow toner remaining on the electrostatic latent image carrier 2Y after the transfer is scraped off by the electrostatic latent image carrier cleaning device 7Y. The surface of the electrostatic latent carrier 2Y is neutralized by the static eliminator 8Y and then charged again by the uniform charger 3Y for the next image forming cycle.

  In the present image forming apparatus 100 that performs multicolor image formation, an image forming process similar to the above is performed electronically at a timing that takes into account the relative positional differences among the electrophotographic image forming units 1Y, 1M, 1C, and 1K. This is also performed in the photographic image forming units 1M, 1C, and 1K, and a full color toner image is formed on the intermediate transfer member 9. The full-color toner image formed on the intermediate transfer member 9 is transferred to the electrophotographic label sheet 18 (recording medium) conveyed to the secondary transfer position at a predetermined timing, and a backup roll 13 that supports the intermediate transfer member 9 and Then, the image is transferred by the pressing force and electrostatic attraction of the secondary transfer roll 12 that constitutes a part of the secondary transfer means that is pressed against the backup roll 13.

  As shown in FIG. 2, the electrophotographic label sheet 18 has a predetermined size from a paper feed cassette 17 serving as an electrophotographic recording medium storage unit disposed in the lower part of the image forming apparatus 100. Paper is fed by 17a. The fed electrophotographic label sheet 18 is conveyed to a secondary transfer position of the intermediate transfer member 9 by a plurality of conveying rolls 19 and registration rolls 20 at a predetermined timing. Then, as described above, the full color toner image is transferred onto the electrophotographic label sheet 18 from the intermediate transfer member 9 by the backup roll 13 and the secondary transfer roll 12 as secondary transfer means. It is like that.

The electrophotographic label sheet 18 on which the full color toner image has been transferred from the intermediate transfer member 9 is separated from the intermediate transfer member 9 and then to the fixing device 15 disposed downstream of the secondary transfer unit. The toner image is fixed to the electrophotographic label sheet 18 by heat and pressure by the fixing device 15.
In order to improve the gloss of the fixed image, a second fixing device may be further provided on the downstream side of the fixing device 15.

  Further, the residual toner on the intermediate transfer member 9 that could not be transferred onto the electrophotographic label sheet 18 by the secondary transfer means is conveyed to the intermediate transfer member cleaning device 14 in a state of adhering to the intermediate transfer member 9 as it is, The toner is removed from the intermediate transfer member 9 by the cleaning unit 14 to prepare for the next image formation.

The fixing device 15 is a pressure belt type fixing device including a fixing roll 30 having a small heat capacity, a pressure belt 31 and a pressure pad 32 as shown in FIG.
The fixing roll 30 has an elastic layer 30b made of silicone rubber having a rubber hardness (JIS-A) of 33 ° on the surface of a core 30a made of aluminum having a thickness of 1.5 mm, an outer diameter of 25 mm, and a length of 380 mm. The elastic layer 30b is covered with a release layer 30c made of a PFA tube having a thickness of 30 μm. A 650 W halogen lamp 33 is disposed inside the fixing roll 30 as a heat source, and the surface temperature of the fixing roll 30 becomes a predetermined temperature (depending on the melting temperature of the toner, generally 140 to 190 ° C.). To heat from inside.

  The pressure belt 31 has a release layer made of a PFA tube having a thickness of 30 μm on the surface of a polyimide belt having a thickness of 75 μm, an outer diameter of 30 mm, and a length of 330 mm. Inside the pressure belt 31 is disposed a pressure pad 32 that presses the pressure belt 31 against the fixing roll 30 to form a nip. The pressing load of the pressure pad 32 is 33 kg, and the nip width is 6.5 mm. There is no heat source on the pressure belt 31 and pressure pad 32 side.

The electrophotographic label sheet transport path 11 in the image forming apparatus 100 is provided on the side surface of the image forming apparatus 100, and the electrophotographic label sheet transport path 11 is configured to be substantially vertical in the drawing. .
The electrophotographic label sheet 18 on which the image is formed and fixed by the substantially vertical electrophotographic label sheet conveyance path 11 can be discharged to the upper part of the image forming apparatus.

  The image forming apparatus 100 is provided with a first print mode (normal print) and a second print mode (high gloss print, that is, a photographic mode), and outputs a normal image with low gloss and non-gloss. When the print mode is selected, the paper is selectively fed from the paper feed cassette 17 in which plain paper or coated paper is stored, transferred to the full color toner image by the secondary transfer means, fixed in the fixing device 15, and then transported. The direction switching gate 16 switches the conveyance path to the first electrophotographic recording sheet discharge port 21 side, and the discharge roll 22 discharges the image forming surface upward onto the plain paper mode discharge tray 25.

  When the photographic mode is selected, the paper is selectively fed from the paper feed cassette 17, transferred to the full color toner image by the secondary transfer means, fixed by the fixing device 15, and then transported by the transport direction switching gate 16. Is switched to the second electrophotographic recording sheet discharge port 23 side, and the discharge roll 24 discharges the image forming surface upward onto the photo mode discharge tray 26.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. In addition, "part" in an Example and a comparative example represents a "mass part" unless there is particular notice.

<Example 1>
(Preparation of electrophotographic label sheet)
-Toner receiving layer forming coating solution-
Polyester resin (trade name: Tufton NE382, manufactured by Kao Corporation, Tg: 60 ° C., storage elastic modulus: 4 Pa) 10 parts Mold release agent (high melting point paraffin wax HNP-10, manufactured by Nippon Seiki Co., Ltd., melting point : 75 ° C.) 0.2 parts Metal oxide (needle-like TiO ₂ coated with SnO ₂ doped with Sb, trade name: FT3000, manufactured by Ishihara Sangyo Co., Ltd., major axis length: 5.15 μm, aspect ratio: 19.1) 1.0 part ・ Dispersant (solvent dispersant, trade name: Homogenol L-1820, manufactured by Kao Corporation) 0.1 part ・ Toluene 90 parts

  The above components were mixed and dispersed at high speed with a stirrer to obtain a toner-receiving layer-forming coating solution.

  As a label base material, a polyethylene terephthalate film (white PET film A, thickness: 50 μm) in which heat shrinkage was suppressed by heat treatment in advance was used. After applying and drying the anchor coat layer on the surface of the roll-shaped label base material, the above-described coating solution for forming the toner receiving layer is applied to the surface of the layer so that the film thickness after drying becomes 5 μm. The label body on which the toner receiving layer was formed was wound up in a roll shape.

-Coating solution for forming antistatic treatment layer-
Polyester resin (trade name: Vylonal MD-1930, manufactured by Toyobo Co., Ltd.) 90 parts by mass Matting agent (PMMA particles having an average particle size of 5 μm) 5 parts by weight Cationic surfactant (trade name: Elegan 264-WAX, Japan) (Oil & Fat Co., Ltd.) 1.0 parts by mass

  As the separator substrate, a heat-resistant polyethylene terephthalate film Z (thickness: 75 μm) whose heat shrinkage was reduced by heat treatment in advance was used. The antistatic treatment layer forming coating solution was applied to one side of the separator substrate so that the film thickness after drying was 0.5 μm. A silicone resin layer having a thickness of 0.5 μm was provided as a release layer on the surface opposite to the surface subjected to the antistatic treatment to form a separator.

  Further, an adhesive layer was provided on the surface of the release layer by applying an acrylic pressure-sensitive adhesive solution with a comma coater so that the dry thickness was 15 μm and drying. Thereafter, the surface of the separator, on which the adhesive layer is formed, and the surface of the label body, which is wound in a roll shape, on which the toner receiving layer is not formed are overlapped with a laminator so that air is not mixed into the adhesive layer, An electrophotographic label sheet 1 was produced.

In the environment of 23 ° C. and 50% RH, the surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 1 at 100 V applied voltage is 1 × 10 ¹³ Ω / □, and the surface resistivity at 1000 V applied voltage. Was 5 × 10 ⁹ Ω / □, and Rz was 10 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □.

(Quality evaluation of electrophotographic label sheets)
On the surface of the electrophotographic label sheet 1 produced as described above, toner is used in a normal temperature and normal humidity environment (22 ° C., 55% RH) using a color printer DocuPrint C2220 (manufactured by Fuji Xerox Co., Ltd.) shown in FIG. After the image was transferred and fixed by the fixing device 15, the following evaluation was performed.

-Toner transferability evaluation-
There is a secondary color of blue and a tertiary color consisting of yellow, magenta, and cyan, and a chart that can output in 10% increments from 0 to 100% of the halftone dot area ratio is used. The printer output was performed, and toner transfer unevenness was visually evaluated according to the following evaluation criteria.
○: Excellent toner transfer unevenness. There is no problem in practical use.
Δ: Inferior toner transfer unevenness. There are practical problems.
X: Toner transfer unevenness is large and inferior. There are practical problems.

-Holocharacter evaluation-
Using a chart that can output a 0.5 mm width line with tertiary colors consisting of yellow, magenta, and cyan, printer output is performed using the electrophotographic label sheet 1, and toner transfer unevenness (holocharacter) according to the following evaluation criteria ) Was visually evaluated.
◎ No toner is missing throughout the line.
○ A small amount of toner is missing from a part of the line. There is no problem in practical use.
Δ: Toner is missing throughout the line. There are practical problems.
X Toner omission occurs remarkably throughout the line. There are practical problems.

-Toner fixability evaluation-
As shown in FIG. 4A, a 2 cm × 2 cm square image that is a tertiary color composed of yellow, magenta, and cyan and has a dot area ratio of 100% for each color is output. 4 (b) is folded inward as shown in FIG. 4 (c), and a cylindrical weight having a width of 3 cm, a diameter of 5 cm, and a weight of 470 g is rolled onto the fold, and then the fold is opened to open the toner. The degree of peeling was evaluated by rubbing visually and with a bencot according to the following evaluation criteria.
○: No peeling at all.
Δ: Peeling occurs slightly, and there is a practical problem when used for a long time.
X: It peels easily only by rubbing lightly.

<Example 2>
In Example 1, the electrophotographic label sheet 2 was prepared in the same manner as in Example 1 except that the amount of the metal oxide in the toner-receiving layer-forming coating solution was 1 part and the thickness after drying was 4 μm. Was made.

The surface resistivity of the toner receiving layer surface at an applied voltage of 100 V was 1 × 10 ¹³ Ω / □, the surface resistivity at an applied voltage of 1000 V was 1 × 10 ⁹ Ω / □, and Rz was 12 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 2 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 3>
-Toner receiving layer forming coating solution-
Polyester resin (trade name: Tufton NE382, manufactured by Kao Corporation, Tg: 60 ° C., storage elastic modulus: 4 Pa) 10 parts Mold release agent (high melting point paraffin wax HNP-10, manufactured by Nippon Seiki Co., Ltd., melting point : 75 ° C.) 0.2 parts Metal oxide (needle-like TiO ₂ coated with SnO ₂ doped with Sb, trade name: FT2000, manufactured by Ishihara Sangyo Co., Ltd., major axis length: 2.86 μm, aspect ratio: 13.6) 1.5 parts Dispersant (solvent-based dispersant, Homogenol L-1820, manufactured by Kao Corporation) 0.1 part Toluene 90 parts

In Example 1, an electrophotographic label sheet 3 was prepared in the same manner as in Example 1 except that the toner-receiving layer-forming coating solution had the above composition.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 3 at an applied voltage of 100 V is 5 × 10 ¹⁴ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 1 × 10 ¹² Ω / □, Rz was 5 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 3 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 4>
In Example 1, an electrophotographic label sheet 4 was produced in the same manner as in Example 1 except that the amount of the cationic surfactant in the coating solution for forming the antistatic treatment layer was changed to 1.1 parts.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 4 at an applied voltage of 100 V is 3 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ⁹ Ω / □, Rz was 10 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹⁰ Ω / □. The electrophotographic label sheet 4 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 5>
In Example 1, the electrophotographic label sheet 5 was produced in the same manner as in Example 1 except that the amount of the cationic surfactant was changed to 0.8 parts in the formulation of the coating solution for forming the antistatic treatment layer. did.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 5 at an applied voltage of 100 V is 3 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ⁹ Ω / □, Rz was 10 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹³ Ω / □. The electrophotographic label sheet 5 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 6>
-Toner receiving layer forming coating solution-
Polyester resin (trade name: Tufton NE382, manufactured by Kao Corporation, Tg: 60 ° C., storage elastic modulus: 4 Pa) 10 parts Mold release agent (high melting point paraffin wax HNP-10, manufactured by Nippon Seiki Co., Ltd., melting point 0.2 parts ・ Metal oxide (Sb-doped SnO ₂ , trade name: FS10P, manufactured by Ishihara Sangyo Co., Ltd., major axis length: 0.2 to 2.0 μm, aspect ratio: 20 to 30) 4 parts Dispersant (solvent-based dispersant, trade name: Homogenol L-1820 manufactured by Kao Corporation) 0.1 part Toluene 90 parts

In Example 1, an electrophotographic label sheet 6 was produced in the same manner as in Example 1 except that the toner-receiving layer-forming coating solution had the above composition.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 6 at an applied voltage of 100 V is 1 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 3 × 10 ¹⁰ Ω / □, Rz was 3 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 6 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 7>
-Toner receiving layer forming coating solution-
Polyester resin (trade name: Tufton NE382, manufactured by Kao Corporation, Tg: 60 ° C., storage elastic modulus: 4 Pa) 10 parts Mold release agent (high melting point paraffin wax HNP-10, manufactured by Nippon Seiki Co., Ltd., melting point : 75 ° C.) 0.2 parts Metal oxide (needle-like TiO ₂ coated with SnO ₂ doped with Sb, trade name: FT3000, manufactured by Ishihara Sangyo Co., Ltd., major axis length: 5.15 μm, aspect ratio: 19.1) 1.0 part Dispersant (solvent-based dispersant, trade name: Homogenol L-1820, manufactured by Kao Corporation) 0.1 part Matte agent (PMMA matte agent having an average particle diameter of 7 μm, trade name: MR-7G, manufactured by Soken Chemical Co., Ltd.) 0.3 part ・ Toluene 90 parts

In Example 1, an electrophotographic label sheet 7 was produced in the same manner as in Example 1, except that the toner-receiving layer-forming coating solution had the above composition.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 7 at an applied voltage of 100 V is 3 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ⁹ Ω / □, Rz was 15 μm. The surface resistance value of the antistatic treatment layer surface at an applied voltage of 1000 V was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 7 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Example 8>
In Example 7, an electrophotographic label sheet 8 was produced in the same manner as in Example 7 except that the amount of the matting agent was 0.5 part.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 8 at an applied voltage of 100 V is 3 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ⁹ Ω / □, Rz was 17 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 8 was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Comparative Example 1>
In Example 1, an electrophotographic label sheet 9 was produced in the same manner as in Example 1 except that the amount of the metal oxide in the toner-receiving layer solution was changed to 1.3 parts.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 9 at an applied voltage of 100 V is 3 × 10 ¹² Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ⁸ Ω / □, Rz was 10 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 9 was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative example 2>
-Toner receiving layer forming coating solution-
Polyester resin (trade name: Tufton NE382, manufactured by Kao Corporation, Tg: 60 ° C., storage elastic modulus: 4 Pa) 10 parts Mold release agent (high melting point paraffin wax HNP-10, manufactured by Nippon Seiki Co., Ltd., melting point 0.2 parts ・ Metal oxide (Sb-doped SnO ₂ , trade name: FS10P, manufactured by Ishihara Sangyo Co., Ltd., major axis length: 0.2 to 2.0 μm, aspect ratio: 20 to 30) 2.5 parts Dispersant (solvent dispersant, Homogenol L-1820, manufactured by Kao Corporation) 0.1 part Matte agent (PMMA mat agent, trade name: MR-7G, manufactured by Soken Chemical Co., Ltd.) 0. 3 parts ・ Toluene 90 parts

In Example 1, an electrophotographic label sheet 10 was produced in the same manner as in Example 1 except that the toner-receiving layer-forming coating solution had the above composition.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 10 at an applied voltage of 100 V is 5 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ¹³ Ω / □, Rz was 8 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 10 was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 3>
In Example 1, the electrophotographic label sheet 11 was produced in the same manner as in Example 1 except that the amount of the cationic surfactant was changed to 1.3 parts in the formulation of the coating solution for forming the antistatic treatment layer. did.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 11 at an applied voltage of 100 V is 3 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ⁹ Ω / □, Rz was 10 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ⁹ Ω / □. The electrophotographic label sheet 11 was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative example 4>
In Example 1, the electrophotographic label sheet 12 was produced in the same manner as in Example 1 except that the amount of the cationic surfactant was changed to 0.4 part in the formulation of the coating solution for forming the antistatic treatment layer. did.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 12 at an applied voltage of 100 V is 3 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ⁹ Ω / □, Rz was 10 μm. The surface resistance value of the antistatic treatment layer surface at an applied voltage of 1000 V was 1 × 10 ¹⁴ Ω. The electrophotographic label sheet 12 was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 5>
-Toner receiving layer forming coating solution-
Polyester resin (trade name: Tufton NE382, manufactured by Kao Corporation, Tg: 60 ° C., storage elastic modulus: 4 Pa) 10 parts Mold release agent (high melting point paraffin wax HNP-10, manufactured by Nippon Seiki Co., Ltd., melting point : 75 ° C) 0.2 part-Matting agent (PMMA matting agent, trade name: MR-7G, manufactured by Soken Chemical Co., Ltd.) 0.3 part-Toluene 90 parts

In Example 1, an electrophotographic label sheet 13 was produced in the same manner as in Example 1, except that the toner-receiving layer-forming coating solution had the above composition.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 13 at an applied voltage of 100 V is 5 × 10 ¹⁴ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ¹⁴ Ω / □, Rz was 8 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 3 was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 6>
-Toner receiving layer forming coating solution-
Polyester resin (trade name: Tufton NE382, manufactured by Kao Corporation, Tg: 60 ° C., storage elastic modulus: 4 Pa) 10 parts Mold release agent (high melting point paraffin wax HNP-10, manufactured by Nippon Seiki Co., Ltd., melting point 0.2 parts ・ Matting agent (PMMA matting agent, trade name: MR-7G, manufactured by Soken Chemical Co., Ltd.) 0.3 part ・ Cationic surfactant (Elegan 364WAX, manufactured by Kao Corporation) 0. 5 parts ・ Toluene 90 parts

In Example 1, an electrophotographic label sheet 14 was produced in the same manner as in Example 1, except that the toner-receiving layer-forming coating solution had the above composition.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 14 at an applied voltage of 100 V is 5 × 10 ¹⁰ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 5 × 10 ¹⁰ Ω / □, Rz was 7 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 14 was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 7>
In Comparative Example 6, an electrophotographic label sheet 15 was produced in the same manner as Comparative Example 6 except that the amount of the cationic surfactant was 0.1 part.
The surface resistivity of the toner receiving layer surface of the electrophotographic label sheet 15 at an applied voltage of 100 V is 1 × 10 ¹³ Ω / □, and the surface resistivity at an applied voltage of 1000 V is 1 × 10 ¹³ Ω / □, Rz was 8 μm. Further, the surface resistivity at an applied voltage of 1000 V on the surface of the antistatic treatment layer was 1 × 10 ¹¹ Ω / □. The electrophotographic label sheet 15 was evaluated in the same manner as in Example 1. The results are shown in Table 2.

  From the results of Examples 1 to 8, it was found that the electrophotographic label sheet of the present invention can be used as an extremely excellent electrophotographic label sheet having good toner transferability, holocharacter, and toner fixing property. . On the other hand, in the electrophotographic label sheet shown in the comparative example, any of the toner transfer property, the holocharacter, and the toner fixing property is bad, and the performance is inferior to the electrophotographic label sheet of the present invention. Met.

It is typical sectional drawing which shows an example of a structure of the label sheet for electrophotography of this invention. 1 is a schematic configuration diagram illustrating a preferred example of an image forming apparatus used in an image forming method of the present invention. 1 is a schematic configuration diagram showing an example of a fixing device applied to an image forming method of the present invention. FIG. 3 is a schematic explanatory diagram for explaining a toner fixing property evaluation method for an electrophotographic label sheet of the present invention.

Explanation of symbols

1Y, 1M, 1C, 1K Electrophotographic forming unit 2Y, 2M, 2C, 2K Electrostatic latent image carrier 3Y, 3M, 3C, 3K Charger 4Y, 4M, 4C, 4K Exposure unit 5Y, 5M, 5C, 5K Development Apparatus 6Y, 6M, 6C, 6K Primary transfer roll 7Y, 7M, 7C, 7K Electrostatic latent image carrier cleaning apparatus 8Y, 8M, 8C, 8K Static neutralizer 9 Intermediate transfer body 10 Stretch roll 11 Electrophotographic label sheet transport Path 12 Secondary transfer roll 13 Backup roll 14 Cleaning means / intermediate transfer member cleaning device 15 Fixing device 16 Transport direction switching gate 17 Paper feed cassette 17a Paper feed roll 18 Electrophotographic label sheet 19 Transport roll 20 Registration roll 21, 23 Electron Photographic recording sheet discharge port 22 Discharge roll 24 Discharge roll 25, 26 Electronic copy True label sheet discharge tray 30 Fixing roll 30a Core 30b Elastic layer 30c Release layer 31 Pressure belt 32 Pressure pad 50 Label body 52 Toner image receiving layer 53 Anchor coat layer 54 Label substrate 55 Adhesive layer 60 Separator 63 Peeling Layer 64 Separator base 65 Antistatic treatment layer 100 Image forming apparatus

Claims (2)

A label body having a pressure-sensitive adhesive layer on one side of a label base material, and a separator that is temporarily bonded to the label body through the pressure-sensitive adhesive layer. The label base material and the separator base material are either Is an electrophotographic label sheet which is also a heat-resistant resin film,
A toner receiving layer containing a metal oxide is formed on the surface of the label substrate opposite to the surface on which the adhesive layer is provided, and the surface resistivity of the toner receiving layer at an applied voltage of 100 V is 1 × 10. ^{It is in} the range of ^{13 to} 5 × 10 ¹⁴ Ω / □, the surface resistivity at an applied voltage of 1000 V is in the range of 1 × 10 ⁹ to 1 × 10 ¹² Ω / □, and is temporarily bonded to the label body of the separator. An electrophotographic label sheet, wherein the surface resistivity at an applied voltage of 1000 V on the surface opposite to the surface to be coated is in the range of 1 × 10 ¹⁰ to 1 × 10 ¹³ Ω / □. As a recording medium, an electrophotographic label sheet composed of a label body and a separator temporarily bonded to the label body through an adhesive layer is used, and a toner image is transferred at least on the surface of the toner receiving layer of the label body. An image forming method comprising: a transfer step; and a fixing step in which the toner image is heated and melted by a fixing device and fixed on the toner receiving layer,
The image forming method according to claim 1, wherein the electrophotographic label sheet according to claim 1 is used as the electrophotographic label sheet.

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