JP2010286856A - Image receiving sheet for electrophotography and image forming system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new image with high artistic quality and is different from a conventional image with uniform gloss over the entire surfaces, by arranging high gloss images partially or regularly. <P>SOLUTION: An image receiving sheet for electrophotography has: a base material; and a toner receiving layer formed, on the base material, from thermoplastic resin in which a glass transition temperature is 40 to 80°C. In the toner receiving layer, an unfixed toner image T is formed on a recording material P having recesses and protrusions by an embossing process. Cooling separation fixing can be performed to obtain a new image, which is excellent in artistic quality and is different from a conventional image with uniform gloss over the entire surfaces, by arranging high gloss images partially or regularly. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic image receiving sheet and an image forming system using the same.

  2. Description of the Related Art Conventionally, image forming apparatuses mainly using an electrophotographic system such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these are widely known. Many products that form full-color images as well as black and white have been commercialized.

  In addition, as image forming apparatuses are used in various fields, the demand for image quality is becoming higher and higher. In particular, as an element for improving the image quality of a full-color image, improvement in uniformity of glossiness is required. One factor that determines the glossiness is the smoothness of the output image.

  In response to such needs, Patent Documents 1 and 2 transfer a color toner made of a thermoplastic resin onto a recording material provided with a thermoplastic transparent resin layer as a toner receiving layer (image receiving layer, glossing layer). An image forming method for forming a color image by heating and melting is disclosed.

  In these image forming methods, as a desirable fixing device, a cooling separation type fixing device (hereinafter referred to as a belt fixing device) including a fixing belt has been proposed.

  The belt fixing device described in Patent Documents 3 and 4 presses and heats a recording material carrying an unfixed toner image with a fixing belt made of a heat-resistant film, and cools the recording material while keeping the recording material in close contact with the fixing belt. To solidify the toner image. The recording material with the toner image cooled and solidified is peeled off from the fixing belt.

  As a result, the toner image is fixed while being embedded in the transparent resin layer of the recording material, and both the transparent resin layer on the recording material surface and the fixed toner image are solidified according to the shape of the fixing belt surface, and the entire surface of the recording material Since the surface becomes smooth, a color image having excellent gloss can be obtained.

  As a recording material having a resin layer used in such an image forming apparatus, a recording material as disclosed in Patent Document 5 has been proposed. Patent Document 5 proposes an electrophotographic transfer sheet in which a resin layer mainly composed of a thermoplastic resin having a glass transition temperature of 85 ° C. or lower is applied to a thickness of about 20 μm.

Japanese Patent Application Laid-Open No. 64-35542 JP 05-216322 A Japanese Patent Laid-Open No. 04-216580 Japanese Patent Laid-Open No. 04-362679 JP 2003-084477 A

  In the recording material and the image forming method using the recording material as described above, a uniform image can be obtained with high gloss over the entire surface of the recording material. However, conversely, it has been difficult to obtain a partially glossy image on the recording material or to improve the artability by interspersing the high gloss image.

  The present invention has been made in view of such problems. Its purpose is to overcome the above-mentioned problems, and by interspersing the high-gloss parts partially or regularly, a new image that is different from the conventional uniform high-gloss image and has excellent design and art. Is to provide.

  Another typical structure of the electrophotographic image-receiving sheet according to the present invention for achieving the above object is a base material and a heat provided on the base material and having a glass transition temperature of 40 ° C. or higher and 80 ° C. or lower. And a toner receiving layer made of a plastic resin, and the toner receiving layer has an uneven portion formed by embossing.

  In addition, a typical configuration of the image forming system according to the present invention for achieving the above object is to smooth the convex portion of the toner receiving layer by heating and pressing the electrophotographic image receiving sheet. An image forming system having a smoothing means that is configured such that the glossiness of the image formed on the convex portion of the toner receiving layer is 20 or more higher than the glossiness of the image formed on the concave portion. And

  According to the present invention, an image formed product interspersed with high gloss portions can be obtained. That is, it is possible to obtain an image formed product excellent in design and art, which is different from the conventional uniform high gloss image on the entire surface.

FIG. 3 is a schematic plan view of a recording sheet in an example. It is a schematic perspective view of a screen printing machine. It is explanatory drawing of a screen printing process. 1 is a schematic diagram illustrating a schematic configuration of an example of an image forming apparatus. FIG. 6 is an enlarged view of first to fourth image forming portions and a transfer belt mechanism portion. It is an enlarged model view of a fixing device portion. 1A is a schematic diagram of a state before fixing in which an unfixed toner image is placed on the recording sheet of FIG. 1, and FIG. 1B is a schematic diagram of a state after fixing after fixing the recording sheet with a belt fixing device. It is. It is a result of the glossiness of the measurement angle of 60 degrees in an Example. It is a plane schematic diagram of the other form of a recording sheet. FIG. 10 is a schematic plan view of still another form of the recording sheet. It is explanatory drawing of the recording sheet in an Example, (a) is a schematic diagram of the recording sheet before embossing, (b) The cross-sectional schematic diagram of the recording sheet after embossing, (b) is the recording sheet after embossing It is a cross-sectional schematic diagram. 11A is a schematic diagram of a state before fixing in which an unfixed toner image is placed on the recording sheet of FIG. 11, and FIG. 11B is a schematic diagram of a state after fixing when the recording sheet is fixed by a belt fixing device. It is. It is a result of the glossiness of the measurement angle of 60 degrees in an Example.

[Example]
(1) Recording Material FIG. 1 is a schematic plan view of a recording material (hereinafter referred to as a recording sheet) P as an electrophotographic image receiving sheet for forming a high-quality image in which a high gloss portion and a low gloss portion coexist. is there.

  A is the base material of the recording sheet P (hereinafter referred to as base paper), B is a transparent (substantially transparent) toner receiving layer (resin layer: image receiving layer / glossing layer: hereinafter referred to as receiving layer) made of thermoplastic resin. ). The base paper A is a commonly used electrophotographic recording sheet, a coated paper having a pigment coating layer, or the like. The receiving layer B is formed in the form scattered with respect to the surface of the base paper A (on the substrate). The transparency of the toner receiving layer is not limited to an example that is sufficiently transparent. For example, the present invention can be similarly applied to a toner receiving layer that is somewhat clouded as long as it does not affect the reproduced image.

  Here, the toner receiving layer is a resin layer that is smoothed by being softened and melted together with a toner image formed on the surface by a smoothing device (fixing device) described later. That is, it can be said that the layer is smoothed by embedding the toner image in the toner receiving layer in accordance with the smoothing processing by the smoothing device. Therefore, the glass transition temperature of the thermoplastic resin constituting the toner receiving layer is set to 40 ° C. or higher and 80 ° C. or lower. On the other hand, the portion of the base material on which the toner receiving layer is not provided is not softened or melted during the smoothing process, so that the glossiness does not increase as compared with the portion of the toner receiving layer and becomes a low gloss portion.

  The reason why the glass transition temperature Tg of the toner receiving layer is set in the above range is as follows.

  First, in this example, as will be described later, the glass transition temperature Tg of the toner used is set to 40 ° C. or higher and 80 ° C. or lower. This is appropriate because if the glass transition temperature Tg of the toner is lower than 40 ° C., the toner is likely to be blocked in the developing device or the like (before forming the unfixed toner image on the recording material). Because there is no. On the other hand, if the glass transition temperature Tg of the toner is higher than 80 ° C., the heating temperature in the smoothing device must be excessively increased, which is not appropriate. The glass transition temperature Tg of this toner can be measured by the method described later.

  Since the toner receiving layer is preferably softened and melted during the smoothing process together with the toner image formed on the recording sheet P using such toner, in this example, the glass transition temperature of the toner and the toner receiving layer is almost equal. Use equal things. That is, as will be described later, both the toner and the toner receiving layer are mainly composed of a polyester resin.

  The glass transition temperature Tg of the toner receiving layer (toner) can be measured by the following method.

  Specifically, the glass transition temperature Tg of the toner receiving layer is determined by ASTM (D3418) using a differential scanning calorimeter (DSC measuring device), DCS-7 (manufactured by Perkin Elmer) or DSC2920 (manufactured by TA Instruments Japan). -82).

  The measurement sample may be 5 to 20 mg, but in this example, 10 mg was accurately weighed. The temperature of the aluminum pan for the sample containing the measurement sample and the empty aluminum pan as a reference is raised and lowered between the measurement temperature ranges (30 to 200 ° C.) as follows.

  First, in order to remove the influence of moisture and the like contained in the resin, the sample and reference aluminum pans are heated (temperature increase I) under the following conditions, and then the temperature is decreased (temperature decrease II).

  Thereafter, the sample and reference aluminum pans are heated (temperature rising III) under the following conditions. The temperature curve (DSC curve) of the resin constituting the toner receiving layer can be obtained from the difference between the temperature curves obtained at this time.

Measurement conditions: Temperature rise I ... 30 ° C → 200 ° C, temperature rise rate 10 ° C / min
Temperature drop II ... 200 ° C → 30 ° C, temperature drop rate 10 ° C / min
Temperature rise III · 30 ° C. → 200 ° C., temperature rise rate 10 ° C./min Tg can be obtained by the midpoint method from the DSC curve of temperature rise III thus obtained.

  The recording sheet P of FIG. 1 is formed by coating the surface of a base paper A with the receiving layer B interspersed in a regular arrangement in the same rectangular shape. In this embodiment, as shown in FIG. 1, the rectangular pattern was regularly dotted with A4 size recording material having a long side length of about 10 mm and a short side length of about 6 mm. As the dotted pattern, as shown in FIG. 1, the A4 size has a total of 49 points, including the above-mentioned seven rectangular patterns at intervals of about 25 mm in the long side direction and the above seven rectangular patterns at intervals of about 20 mm in the short side direction. I was there. The pattern in the long side direction of the recording material was interspersed with the phase being alternately shifted for each line. In this embodiment, the receiving layers B are interspersed as shown in FIG. 1, but it goes without saying that this pattern, size, and arrangement pattern are not necessarily limited to the configuration of this embodiment. Moreover, although the example which arranges many patterns at equal intervals was demonstrated, the space | interval of a pattern should just be the same, and it may be a case where a space | interval has shifted | deviated somewhat by a manufacturing error.

  Further, the patterns of the receiving layer B are not necessarily the same. Specifically, for example, a configuration in which a rectangular shape as in FIG. 1 and a heart shape as in FIG. 9 are alternately arranged regularly may be employed. Furthermore, the pattern of the receiving layer B may be a character. Specifically, for example, a configuration in which a large number of characters CANON (registered trademark) are regularly arranged obliquely with respect to the recording sheet may be employed.

  This recording sheet P has the greatest feature that the receiving layer B melts near the fixing temperature. As a result, as described later, since the toner image is embedded in the receiving layer B when the toner image is fixed on the recording material P, a high gloss toner surface can be obtained.

  The recording sheet P as described above, for example, by using a coated paper having a pigment coating layer as the base paper A and applying a thermoplastic transparent resin layer as a receiving layer B thereto by silk screen printing or the like. Manufactured. As a result, the pigment layer of the coated paper used as the base paper A is formed under the receiving layer B, and a high white and smooth surface is formed. Therefore, it is necessary to mix the pigment with the resin of the receiving layer B which is the outermost layer. The function of increasing the whiteness is also unnecessary. Therefore, the thermoplastic transparent resin layer constituting the receiving layer B, which is the outermost layer of the recording sheet P, can be designed with priority given to the functions of increasing the glossiness and embedding the toner image.

  An example of a specific method for manufacturing the recording sheet P will be introduced. As the base paper A, a coated paper on which a pigment coating layer is formed is used. By applying a thermoplastic transparent resin to one or both sides of this base paper A using silk screen printing, a recording sheet P coated with a receiving layer B in a form that is partially or regularly scattered is used. Can be made.

  FIG. 2 is a schematic perspective view of the screen printing machine, and FIG. 3 is an explanatory diagram of the screen printing process. In screen printing, the four sides of the screen 42 are tension-fixed to the plate frame 41, and a plate film is formed thereon by a manual method or an optical method. The screen 42 is a mesh-like woven fabric mainly using nylon, tetron, stainless steel or the like as a material. Then, the screen printing ink 43 is put into the plate frame 41 in a shallow box shape, and the plate upper surface (screen upper surface) is rubbed while being pressed with a thick spatula rubber called a squeegee 44. As a result, the ink 43 is pushed out from the plate film portion through the surface of the screen 42 onto the surface of the printing medium A placed on the lower surface of the plate, and printing is performed.

  As a major feature of this printing, the mesh of the screen 42 can be changed by exchanging the plate frame 41. Also, regarding the thickness and surface property of the coating film, the material of the screen 42, the hardness and angle of the squeegee 44, Further, it can be managed by a distance 46 between the plate frame 41 and the surface of the printing medium A.

  First, as shown in FIG. 3A, the printing ink 43 is put in the plate frame 41, and the hardness, angle and pressure of the squeegee 44 are adjusted. When the plate frame 41 is lowered as shown in (b), the squeegee 44 is moved, and as shown in (c), the ink 43 is applied to the surface of the printing medium A through the screen. In (d), the plate frame 41 rises again to complete printing. The remaining ink 43 is stored in a place called an ink return (scraper) 45, and the same process is repeated at the next printing.

  Regarding multilayer coating, the same process is printed one by one, and after drying, the next layer is coated in the same process.

  By using such a method, the base paper A of the recording sheet P is used as the printing material, the thermoplastic transparent resin is used as the screen printing ink, and the receiving layer B made of the thermoplastic transparent resin is partially or on the surface of the base paper. It can be formed by coating in a regularly dispersed form.

  As the thermoplastic transparent resin constituting the receiving layer B, a polyester resin, a styrene-acrylate resin, a styrene-methacrylate resin, or the like can be used. In particular, it is preferable to use a polyester resin.

  The following are illustrated as a polyhydric alcohol component and polyhydric carboxylic acid component which comprise a polyester resin.

  Polyhydric alcohol components include ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, a monomer obtained by adding olefin oxide to bisphenol A, and the like can be used.

  Examples of the polyvalent carboxylic acid component include maleic acid, maleic anhydride, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, malonic acid, succinic acid, glutaric acid, dodecyl succinic acid, n-octyl succinic acid, and n-dodecyl succinic acid. Acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2 -Methyl-2-methylenecarboxypropane, tetra (methylenecarboxy) methane, 1,2,7,8-octanetetracarboxylic acid, trimellitic acid, pyromellitic acid, lower alkyl esters of these acids, and the like can be used. .

  The polyester resin is synthesized by polymerization of one or more of the polyhydric alcohol components and one or more of the polyvalent carboxylic acid components.

  As the resin component of the toner, a polyester resin is used for the color toner, and a styrene-acrylic resin is mainly used for the monochrome toner. Therefore, it is preferable to select a thermoplastic resin that constitutes the receiving layer B that has high compatibility with the toner.

  Accordingly, one or a mixture of two or more of polyester resin, styrene-acrylic acid ester resin, styrene-methacrylic acid ester resin and the like is used depending on the purpose.

Furthermore, the transparent resin layer as the receiving layer B can contain a pigment, a release agent, a conductive agent, and the like as long as the transparency is not hindered. In that case, it is preferable that the resin amount of the main component is 80 weight or more with respect to the total weight of the resin layer. Further, the transparent resin layer as the receiving layer B is preferably one whose composition is adjusted so that the surface electric resistance is 8.0 × 10 ⁸ Ω or more at a temperature of 20 ° C. and a relative humidity of 85.

  The manufacturing method of the recording sheet P is not limited to the above manufacturing method. Needless to say, it is not always necessary to use a multilayer structure as long as the coated paper is provided with a thermoplastic resin layer having a melting property that melts near the fixing temperature, and various additives such as pigments may be added. .

  Next, the melting characteristics of the resin constituting the receiving layer B near the fixing temperature will be described.

  Melting properties are examined by measuring viscoelastic properties using a plastic-liquid, emulsion or dispersion resin-viscosity measuring method (JIS K 7117-2) with a constant shear rate using a rotational viscometer. be able to.

When such a measurement is performed on the surface of a coated paper having a resin whose surface layer melts in the vicinity of the fixing temperature, a preferable storage elastic modulus is 1 × 10 ⁷ Pa · s or less at 150 ° C. A more preferable storage elastic modulus is considered to be 1 × 10 ⁶ Pa · s or less at 150 ° C.

  However, when the surface of the coated paper has a multilayer structure, such viscoelasticity measurement is often not possible.

In other words, the outermost layer is coated with 1 to 10 μm of 1 × 10 ⁷ Pa · s resin at a storage elastic modulus of 150 ° C., and 1 × 10 ³ Pa · s resin at a storage elastic modulus of 150 ° C. is formed thereunder. Even when the coating is performed with a thickness of 10 to 50 μm, effects such as a change in glossiness and embedding toner can be obtained. However, in order to function as a whole of multiple layers, the combination of the storage elastic modulus of a single resin or the storage elastic modulus of a resin in which a plurality of resins are mixed can express the effect of changing glossiness or embedding toner. difficult.

  In addition, it is very difficult to collect such an amount that allows such viscoelasticity measurement for the outermost layer resin of ordinary coated paper.

  Therefore, in this embodiment, the following coated paper (melting characteristic) discrimination method is used. That is, a method for discriminating between normal coated paper whose surface layer does not melt and coated paper having a resin layer whose surface layer melts near the fixing temperature will be described.

  First, the coated paper is plunged into the fixing device, and the coated paper is kept in the fixing nip for 5 seconds to be sufficiently heated and then taken out. At this time, the coated paper is discriminated by checking the state of the surface of the recording material (whether or not the resin is melted).

  Specifically, when such a measurement is performed, in the coated paper using a resin that melts at the fixing temperature, the resin on the paper surface melts and is extruded from the fixing nip, so that the mark on the fixing nip remains as a step. Become. Therefore, it can be determined by the presence or absence of this step. Since the resin protrudes upstream in the direction of travel, this step rises upstream and becomes thin in the nip, and the resin melted downstream of the nip is crushed downstream after passing through the nip. Become. Although the height of the step depends on the thickness of the resin layer, a step of about 1 to 10 μm is formed.

  On the other hand, in the coated paper using the pigment coating layer that does not melt near the fixing temperature, there are almost no steps and gentle unevenness due to being pressurized in the nip. Moreover, discoloration may be seen by heating.

  Although the method described above can determine the melting characteristics of the coated paper, the following method may be used. For example, a metal rod having a certain weight heated near the fixing temperature (for example, about 180 °) is placed on the coated paper for a certain period of time and then lifted. It is determined by observing whether or not there is a trace of the metal bar at the position of the coated paper on which the metal bar is placed.

Among such recording materials, the recording sheet P used in this example is a polyester (thermoplastic resin) as a receiving layer B on one side of a coated paper having a basis weight of 170 g / m ² as a base paper (base material) A. A transparent resin layer containing as a main component is provided with a thickness of 20 μm.

When a test piece was made of the polyester resin alone used as the receiving layer B and the coefficient of thermal expansion was measured, it was 7 × 10 ⁻⁵ / ° C.

  In this embodiment, an image was formed on the recording sheet P described above using the following image forming apparatus and fixing apparatus. The image forming apparatus and the fixing device will be described.

(2) Image Forming Apparatus FIG. 4 is a schematic diagram showing a schematic configuration of an example of a suitable image forming system according to the present invention.

  The image forming apparatus constituting this image forming system is a four-color full-color laser printer using an electrophotographic process. This image forming apparatus can form an image on the recording sheet P as an electrophotographic image receiving sheet described above or on a normal sheet. Reference numeral 101 denotes a printer main body. A reader mechanism 102 is provided on the upper surface side of the printer main body 101. Reference numeral 103 denotes a large-capacity paper feeding device provided on the right side of the printer main body 101 in the drawing. Hereinafter, an example of forming an image on the recording sheet P will be described.

  Next, various image forming apparatuses as image forming means for forming an unfixed toner image on the recording sheet P will be described.

  In the printer main body 101, Pa, Pb, Pc, and Pd are first to fourth image forming units arranged in-line (in-line configuration, tandem type) in the horizontal direction from right to left in the drawing. Reference numeral 104 denotes a laser scanning mechanism (laser scanner) having a plurality of optical scanning units disposed above the first to fourth image forming units Pa, Pb, Pc, and Pd. A transfer belt mechanism 105 is provided below the first to fourth image forming portions Pa, Pb, Pc, and Pd. A fixing device 106 is disposed downstream of the transfer belt mechanism 105 in the recording material conveyance direction. Reference numerals 107 and 108 denote first and second paper feed cassettes arranged in two upper and lower stages below the transfer belt mechanism 105. Reference numeral 109 denotes a manual paper feed tray disposed on the right side of the printer main body 101 in the drawing. The manual paper feed tray 109 can be folded and stored with respect to the printer main body 101 as shown by a solid line. When in use, open it as shown by the two-dot chain line.

  A reader mechanism 102 performs color separation reading processing on image information of a full-color document by a photoelectric conversion element (solid-state imaging element) such as a CCD.

  The laser scanning mechanism 104 outputs laser light modulated in accordance with each color separation read image information from the reader mechanism 102 to the first to fourth image forming portions Pa, Pb, Pc, and Pd.

  FIG. 5 is an enlarged view of the first to fourth image forming portions Pa, Pb, Pc, and Pd and the transfer belt mechanism 105. The first to fourth image forming units Pa, Pb, Pc, and Pd have the same configuration. That is, each has an electrophotographic photosensitive drum (hereinafter referred to as a drum) 1 as an image carrier. An entire exposure lamp (discharge lamp) 2, a primary charger 3, a developing device 4, a transfer charger 5, a cleaner 6 and the like, which are process means acting on the drum 1, are provided. The developing devices 4 of the first to fourth image forming portions Pa, Pb, Pc, and Pd are filled with predetermined amounts of yellow, magenta, cyan, and black toners by a supply device, respectively.

  The transfer belt mechanism 105 includes an endless transfer belt 7, a drive roller 7 a and a turn roller 7 b, 7 c that suspends the transfer belt 7. The drive roller 7a is rotationally driven by a drive motor M via a power transmission device such as a timing belt device, whereby the transfer belt 7 is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined speed. The transfer belt 7 is composed of a dielectric resin sheet such as a polyethylene terephthalate resin sheet (PET resin sheet), a polyvinylidene fluoride resin sheet, or a polyurethane resin sheet. A seamless belt is used that has an endless shape in which both ends of the sheet are overlapped and joined to each other, or has no seam.

  The operation for forming a full-color image is as follows. The first to fourth image forming units Pa, Pb, Pc, and Pd are sequentially driven in accordance with the timing of image formation. In response to the driving, each drum 1 rotates in the clockwise direction indicated by the arrow. The transfer belt 7 of the transfer belt mechanism 105 is also driven to rotate. The laser scanning mechanism 104 is also driven. In synchronization with this drive, the primary charger 3 uniformly charges the surface of the drum 1 to a predetermined polarity and potential. The laser scanning mechanism 104 performs laser beam scanning exposure L corresponding to the image signal on the surface of each drum 1. As a result, an electrostatic latent image corresponding to the image signal is formed on the surface of each drum 1. That is, the laser scanning mechanism 104 scans the laser light emitted from the light source device by rotating the polygon mirror 8, deflects the light beam of the scanning light by the reflection mirror, and condenses it on the bus 1 of the drum 1 by the fθ lens. To expose. As a result, an electrostatic latent image corresponding to the image signal is formed on the photosensitive drum. The formed electrostatic latent image is developed as a toner image by the developing device 4.

  By the electrophotographic image forming process operation as described above, a yellow toner image corresponding to the yellow component image of the full color image is formed on the peripheral surface of the drum 1 of the first image forming portion Pa. A magenta toner image corresponding to the magenta component image of the full-color image is formed on the peripheral surface of the drum 1 of the second image forming unit Pb. A cyan toner image corresponding to the cyan component image of the full-color image is formed on the peripheral surface of the drum 1 of the third image forming unit Pc. A black toner image corresponding to the black component image of the full-color image is formed on the peripheral surface of the drum 1 of the fourth image forming unit Pd.

  On the other hand, the sheet feeding roller of the sheet feeding unit selected and designated among the large capacity sheet feeder 103, the first sheet feeding cassette 107, the second sheet feeding cassette 108, and the manual sheet feeding tray 109 is driven. As a result, the recording sheets P stacked and stored in the sheet feeding unit are separated and fed. Then, the toner is supplied onto the transfer belt 7 of the transfer belt mechanism 105 through a plurality of conveyance rollers and the registration rollers 9. The recording sheet P supplied onto the transfer belt 7 is sequentially conveyed to the transfer portions of the first to fourth image forming portions Pa, Pb, Pc, and Pd by conveyance by the transfer belt 7.

  That is, when the transfer belt 7 of the transfer belt mechanism 105 is rotationally driven by the drive roller 7a and is confirmed to be in a predetermined position, the recording sheet P is sent out from the registration roller 9 to the transfer belt 7, and the first Is conveyed toward the transfer portion of the image forming portion Pa. At the same time, the image writing signal is turned on, and image formation is performed on the drum 1 of the first image forming unit Pa at a certain timing with reference to the signal. The transfer charger 5 applies an electric field or electric charge at the lower transfer portion of the drum 1, whereby the first color yellow toner image formed on the drum 1 is transferred onto the recording sheet P. By this transfer, the recording sheet P is firmly held on the transfer belt 7 by an electrostatic adsorption force, and subsequently conveyed sequentially to the transfer portions of the second to fourth image forming portions Pb, Pc, and Pd. The toner images of magenta, cyan, and black that are formed on the photosensitive drums of the image forming units are sequentially superimposed and transferred. As a result, a four-color full-color unfixed toner image is synthesized and formed on the recording sheet P.

  The recording sheet P on which the four-color full-color toner image is synthesized and formed is separated from the end of the transfer belt 7 by being neutralized by the separation charger 10 at the downstream portion in the conveyance direction of the transfer belt 7 and the electrostatic adsorption force is attenuated. To do. In particular, in a low humidity environment, the recording sheet P is dried and the electrical resistance is increased, so that the electrostatic adsorption force with the transfer belt 7 is increased, and the effect of the separation charger 10 is increased. Usually, since the separation charger 10 charges the recording sheet P in a state where the toner image is not fixed, a non-contact charger is used.

  The recording sheet P peeled off from the transfer belt 7 is conveyed to the fixing device 106 and heated and pressed by the fixing device 106 to mix the color toner images and fix (fix) the recording sheet P on the recording sheet P. It becomes a formation.

  When the single-sided image forming mode is selected, the recording sheet P that has exited the fixing device 106 passes above the selector 11 that is held in the first posture, and is discharged from the discharge port 13 by the discharge roller 12. The paper is discharged onto an external paper discharge tray 110.

  When the double-sided image formation mode is selected, the first-fixed recording sheet P that has exited the fixing device 106 is rerouted to the reverse refeed mechanism 111 side by the selector 11 switched to the second posture. The Then, the reverse part (switchback mechanism) 14 of the reverse refeed mechanism 111 is reversed and sent to the double-sided conveyance path 15 and temporarily stored in the intermediate tray 16.

  The recording sheet P stored in the intermediate tray 16 is sent out from the intermediate tray 16 toward the registration roller 9 by a paper feed roller driven at a predetermined control timing. Then, the sheet is fed again from the registration roller 9 onto the transfer belt 7 of the transfer belt mechanism 105 with the second side facing upward. As a result, as in the case of image formation on the first surface of the recording sheet P, the first to fourth image forming portions Pa, Pb, Pc, and Pd perform the combined formation of the four-color full-color toner images on the second surface. The

  The recording sheet P that has undergone toner image formation on the second side is separated from the transfer belt 7 and conveyed to the fixing device 106. Then, the fixing device 106 receives the toner image fixing process on the second surface, passes through the upper side of the selector 11 switched to the first posture, and is discharged from the discharge port 13 to the discharge tray 110 outside the apparatus by the discharge roller 12. Are discharged as a double-sided image formed product.

  It is also possible to output a monochrome image formation or a single color image formation. In this case, when the image forming mode is selected, only the image forming unit corresponding to the selected image forming mode among the first to fourth image forming units Pa, Pb, Pc, and Pd performs the image forming operation. In this image forming unit, the photosensitive drum is driven to rotate, but the image forming operation is not performed. Then, a sequence for transferring the toner image to the recording sheet P conveyed by the transfer belt mechanism 105 is executed in the transfer unit of the image forming unit that has performed the image forming operation.

(3) Fixing device 106
Next, a fixing device as a smoothing device will be described. The smoothing device is not limited to a belt fixing device described later, and may be any other configuration as long as it can smooth the recording sheet provided with the toner receiving layer.

  FIG. 6 shows an enlarged model view of the fixing device 106. The fixing device 106 in this embodiment is a cooling separation type belt fixing device including a fixing belt.

  The belt fixing device 106 is disposed on the first fixing roller 51, a rotating roller 53 as a separation roller disposed at a predetermined distance from the first fixing roller 51, and an upper side of the rotating roller 53. And a rotating roller 54 as a tension roller. An endless (endless) fixing belt 57 (glossy belt) is suspended around the three rollers 51, 53, and 54. A second fixing roller 52 (nip forming member) is provided as a pressure roller that is pressed against the first fixing roller 51 with the fixing belt 57 interposed therebetween.

  Hereinafter, the first fixing roller 51 is referred to as a fixing roller 51. The rotating roller 53 is referred to as a separation roller 53. The rotating roller 54 is referred to as a tension roller 54. The second fixing roller 52 is referred to as a pressure roller 52.

  An auxiliary roller 55 is provided in contact with the outer surface of the fixing belt at a position near the separation roller 53 at a fixing belt portion between the fixing roller 51 and the separation roller 53. Further, inside the fixing belt 57, a cooling fan 56 is provided between the fixing roller 51 and the separation roller 53, and air-cools the fixing belt portion between the fixing roller 51 and the separation roller 53. The fixing roller 51, the pressure roller 52, the separation roller 53, the tension roller 54, and the auxiliary roller 55 are arranged substantially in parallel with each other.

  The fixing roller 51 has a concentric three-layer structure and has a core portion, an elastic layer, and a release layer. The core portion is composed of an aluminum hollow pipe having a diameter of 44 mm and a thickness of 5 mm. The elastic layer is made of silicone rubber having a JIS-A hardness of 50 degrees and a thickness of 300 μm. The release layer is made of PFA having a thickness of 50 μm. A halogen lamp 58 as a heat source (roller heater) is disposed inside the hollow pipe of the core portion.

  The pressure roller 52 has the same configuration. The elastic layer uses silicone rubber having a thickness of 3 mm. This is to earn a fixing nip by the elastic layer. Reference numeral 59 denotes a halogen lamp as a heat source (roller heater) disposed inside the hollow pipe of the core portion of the pressure roller 52.

  The fixing roller 51 and the pressing roller 52 are pressed against each other with a predetermined pressing force with the fixing belt 57 interposed therebetween, thereby forming a fixing nip portion N as a heating / pressing portion having a predetermined width in the recording material conveyance direction. The pressure applied by the pressure roller 52 was 490 N (50 kgf) in total pressure. At this time, the width of the fixing nip portion N was 5 mm.

  Here, the surface hardness of the fixing roller 51 needs to be selected according to the fixing belt 57. If the surface hardness of the fixing roller 51 is soft, the fixing belt 57 is bent, and the toner is not sufficiently pushed into the receiving layer of the recording material, so that a toner step remains. When the hardness of the fixing belt 57 is soft, the fixing roller 51 is sufficiently hard so that the elastic layer is thinned or eliminated, and only the surface layer of PFA is used, or only the aluminum core is used. Also good.

  The material of the surface of the fixing belt 57 is made of silicone rubber, fluororubber, fluororesin, polyimide resin or the like, and has a highly glossy mirror surface. Specifically, the fixing belt 57 is heated while being in close contact with the image surface of the recording sheet P formed so that the toner-receiving layers are scattered, so that the high gloss surface property is imparted to the image surface of the recording sheet P. It has a function to transfer to. Therefore, in this example, the fixing belt 57 having a glossiness (60 °) of 60 or more and 100 or less is used. The glossiness of the belt can be arbitrarily selected according to the glossiness of the image required in the image forming apparatus. Further, the glossiness of the belt was measured using a handy gloss meter (PG-1M) manufactured by Nippon Denshoku Industries Co., Ltd. (JIS Z) when both the incident angle and the light receiving angle were 60 °. 8741). In this example, a fixing belt having a gloss level of 90 is used.

  The fixing roller 51 is rotationally driven at a predetermined speed in a clockwise direction indicated by an arrow by a driving mechanism (not shown). As the fixing roller 51 rotates, the fixing belt 57 rotates in the clockwise direction indicated by the arrow. The separation roller 53, the tension roller 54, the pressure roller 52, and the auxiliary roller 55 rotate following the rotation of the fixing belt 57. The tension roller 54 applies a predetermined tension to the fixing belt 57.

  Electric power is supplied to the halogen lamps 58 and 59 disposed inside the fixing roller 51 and the pressure roller 52, respectively, and the fixing roller 51 and the pressure roller 52 are internally heated by the heat generated by the halogen lamps 58 and 59, so that the surface temperature is increased. Rises. The surface temperatures of the fixing roller 51 and the pressure roller 52 are respectively detected by a thermistor (not shown), and the detected temperatures of the thermistors are fed back to a control circuit (not shown). The control circuit controls the electric power supplied to the halogen lamps 58 and 59 so that the detection temperature input from each thermistor is maintained at a predetermined temperature set for each of the fixing roller 51 and the pressure roller 52. That is, the temperature of the fixing roller 51 and the pressure roller 52 are controlled to a predetermined temperature, and the temperature of the fixing nip portion N is controlled to a predetermined fixing temperature.

  The recording sheet P having an unfixed toner image on the surface, which is sent from the transfer belt mechanism 105 side to the belt fixing device 106 side, is introduced between the fixing belt 57 and the pressure roller 52 in the fixing nip portion N to be fixed to the fixing nip. The portion N is nipped and conveyed. The unfixed toner image surface of the recording sheet P faces the surface of the fixing belt 57. The recording sheet P is heated and pressurized in the process of being nipped and conveyed through the fixing nip portion N, whereby the color toner images are mixed and fixed to the recording sheet P (fixing). At the same time, the recording sheet P adheres to the surface of the fixing belt 57. Thereafter, the recording sheet P is conveyed in a cooling region (cooling portion) R between the fixing nip portion N and the separation roller 53 as the fixing belt 57 rotates while being in close contact with the fixing belt 57. In this cooling region R, the fixing belt 57 and the recording sheet P are forcibly and efficiently cooled by the action of an air flow flowing through a cooling fan 56 as a cooling means and an air duct 56a surrounding the cooling fan 56. The cooling fan 56 generates an air flow orthogonal to the paper surface. In this example, in order to prevent the toner and the toner receiving layer from being offset to the belt, the recording sheet is cooled to the glass transition temperature (50 ° C.) of the toner (toner receiving layer) by a cooling fan. .

  Thus, the recording sheet P in close contact with the surface of the fixing belt 57 is sufficiently cooled together with the fixing belt 57 in the cooling region R. Then, it reaches the position of the separation roller 53 and is separated (curvature separation) from the surface of the fixing belt 57 by its own rigidity (strain) in a region where the curvature of the fixing belt 57 changes by the separation roller 53. That is, the recording material sheet P is moved in close contact with the fixing belt 57 and cooled before being separated from the fixing belt 57.

  The auxiliary roller 55 prevents the recording material P from being peeled off from the surface of the fixing belt 57 in the middle of the fixing belt cooling region R from the fixing roller 51 to the separation roller 53, thereby preventing the image from being disturbed or being unable to be conveyed.

  Needless to say, the cooling means 56 is not limited to a fan, but may be a contact-type cooling system. A Peltier element, a heat pipe, or a water circulation type cooling device may be used.

(4) Glossy Image Formed Product When a glossy image formed product is output, a sheet having a toner receiving layer B made of resin on the surface is used as the recording sheet P. In this case, the toner of the unfixed toner image is heated and softened and the receiving layer B is also softened by heating by the fixing belt 57 in the process in which the recording sheet P is nipped and conveyed through the fixing nip portion N. Further, when the pressure at the fixing nip N is applied, the heat-softened toner is buried in the heat-softened receiving layer B. At the same time, the recording sheet P is in close contact with the surface of the fixing belt 57. Thereafter, the recording sheet P is conveyed through the cooling region R along with the rotation of the fixing belt 57 in a state of being in close contact with the fixing belt 57, and is forcibly and efficiently cooled sufficiently. Then, the curvature is separated from the surface of the fixing belt 57 in a region where the curvature of the fixing belt 57 changes by the separation roller 53.

  The temperature of the cooling part is preferably set lower than the glass transition temperature Tg of the toner resin. This is because the surface of the toner resin is not sufficiently solidified when it is not cooled to a temperature lower than the glass transition temperature Tg. For this reason, the toner resin may partially adhere to the surface of the fixing belt 57 when the recording sheet is separated, thereby impairing the smoothness of the toner image surface. In such a case, the smoothness of the toner surface after separation of the recording sheet becomes insufficient, and it becomes impossible to obtain a sufficiently high gloss even at a location where high gloss is originally desired. Further, since the toner resin is not sufficiently solidified, the adhesion between the fixing belt 57 and the toner resin is large, and the separation failure of the recording sheet from the fixing belt surface may occur.

  Now, in this embodiment, as shown in FIG. 1, an image is formed using a recording sheet P formed in a form in which the receiving layer B is scattered with respect to the surface of the base paper (base material) A. The description of the image when the image is formed will be described with reference to the schematic cross-sectional view of FIG. FIG. 7 is a conceptual diagram. That is, in practice, since the toner image is formed on the recording sheet P according to the image to be formed (reproduced image), the applied amount of toner differs depending on the portion of the recording sheet P except for a special image. There are many.

The low gloss base paper A of the recording sheet P is a coated paper having a basis weight of 170 g / m ² . In the receiving layer B, a transparent resin layer mainly composed of polyester (thermoplastic resin) is formed on one side (coating layer side) of the base paper A with a thickness of 20 μm and a rectangular shape. In the same pattern, it is formed by coating in a regular arrangement. In this example, the toner used is also a resin powder mainly composed of polyester.

  FIG. 7A is a schematic diagram of a state before fixing in which an unfixed toner image T is placed on the recording sheet P described above. FIG. 6B is a schematic diagram of a post-fixing state in which the recording sheet P is fixed using the belt fixing device 106 described above.

  In (b), C schematically shows the shape after fixing of the toner image portion corresponding to the portion where the receiving layer B of the recording sheet P is not coated, and D is the coating of the receiving layer B of the recording sheet P. The shape after fixing of the toner image portion corresponding to the marked portion is schematically shown.

  The receiving layer B and the fixed toner image portion D, which are fixed in a state where the toner image is embedded in the receiving layer B, are coagulated and become a smooth surface following the mirror surface shape of the belt, so that the glossiness is excellent. It becomes the image part. In addition, the receiving layer B having no toner image is solidified according to a mirror-like belt surface shape and becomes a smooth surface excellent in gloss.

  On the other hand, the surface of the fixing toner image portion C corresponding to the portion where the receiving layer B of the recording sheet P is not coated does not become a smooth surface depending on the surface property of the base paper and the amount of toner loaded. Can not get a good gloss. In addition, the surface of the recording paper P where the receiving layer B is not coated and where there is no toner image reflects the surface property (low glossiness) of the base paper, and sufficient gloss cannot be obtained.

  That is, the portion having the receiving layer B of the recording sheet P becomes a high gloss portion where there is no toner image, and the portion without the toner layer becomes a low gloss portion where there is no toner image. . As a result, a non-glossy image can be obtained, and an image excellent in art can be provided in a form in which high-gloss images are partially or regularly scattered.

  Specifically, the recording sheet P of FIG. 1 was used to form an image with the image forming apparatus of FIG. The belt fixing device 106 described with reference to FIG. 6 is used. The settings are as follows: the fixing temperature is 150 ° C., the fixing speed is 50 mm / sec, the pressing force is 50 kg, and the surface temperature of the fixing belt 57 on the separation roller 53 is the glass transition point of the toner resin. The output of the cooling means 56 was adjusted so as to be 50 ° C., which is a temperature lower than Tg.

  Here, as smoothing conditions (fixing conditions) for satisfactorily smoothing the toner receiving layer (fixing process) having a glass transition temperature of 40 to 80 ° C., fixing temperature, fixing speed, and applied pressure described later are used. At least one is included.

  The fixing temperature (heating temperature: target temperature of the fixing roller 51) is set to a range of 100 ° C. or more near the softening point temperature of the toner and 170 ° C. or less (100 ° C. to 170 ° C.) near the paper blister generation temperature. It is preferable to do. The paper blister refers to a phenomenon in which water in the base paper is excessively heated to become water vapor, which breaks through the toner receiving layer and is discharged to the outside.

  The fixing speed (sheet conveyance speed: conveyance speed of the recording sheet P) is preferably set to a range of 25 mm / sec or more and 75 mm / sec or less (25 mm / sec or more and 75 mm / sec or less). Further, it is preferable to set the pressure (the pressure between the belt 57 and the pressure roller 52) within a range of 25 kg (245N) to 75 kg (735N) (245N to 735N).

Then, in the output image-fixed recording sheet, the solid image gloss on the toner surface of the fixed toner image portion D corresponding to the location where the receiving layer B is applied, and the location where the receiving layer B is not applied The solid image gloss of the toner surface of the fixed toner image portion C corresponding to 1 was measured. This gloss measurement was performed using a gloss meter PG-1M manufactured by Nippon Denshoku Industries Co., Ltd., and the gloss at an incident angle of 60 ° and a light receiving angle of 60 ° (gloss value at a measurement angle of 60 °) was measured. Image conditions used for measurement uniformly toner two colors on the entire surface of the recording sheet P, to determine the position of image formation in an amount of total 1.2 mg / cm ² by the respective color 0.6 mg / cm ^2. A so-called solid image was uniformly formed on the entire surface of the recording sheet P.

  The gloss value G1 of the fixed toner image portion D corresponding to the place where the receiving layer B is applied is 90, and high gloss is obtained, whereas it corresponds to the place where the receiving layer B is not applied. The gloss value G2 of the fixed toner image portion thus obtained was 50, indicating a low gloss.

  The glossiness of the recording sheet at this time is shown in FIG. FIG. 8 shows the glossiness measured at a measurement angle of 60 ° along the X line of the recording sheet P in FIG. When this was seen, the high gloss value whose gloss value G1 is 90 was obtained in the location where the receiving layer B was coated. In addition, a low gloss value having a gloss value G2 of 50 was obtained at a location where the receiving layer B was not applied, and a high gloss image was regularly obtained at a location where the receiving layer B was applied. . That is, depending on the toner image formed by subjecting the recording sheet P provided with the above-described toner receiving layers to the smoothing process (fixing process) by the above-described smoothing apparatus (fixing apparatus). Therefore, an output product in which a high gloss part and a low gloss part having a glossiness of 20 or more are mixed can be obtained.

  As described above, with the configuration of this example, the glossiness of the high gloss portion and the low gloss portion is at least 20 with respect to one recording sheet P regardless of the toner image to be formed. Different images can be formed as described above.

  The fixed toner image portion D of the high gloss surface is scattered in the fixed toner image portion C of the low gloss surface in an arbitrary pattern with a uniform or non-uniform array distribution, so that the angle of the recording sheet P with respect to the human line of sight In other words, the high gloss fixed toner image portion D is partially lifted and recognized. That is, it is possible to provide a new image formed product.

  The fact that the image portion D having the high gloss value G1 is interspersed in the image portion C having the low gloss value G2 has a large image gloss contrast, so that the difference is remarkably recognized by human vision. Such an image can be said to be a special image with high design and artistic properties, unlike the conventional configuration in which the entire surface of the recording sheet P is made highly glossy.

  It is preferable that the difference in contrast between the high gloss image portion D and the low gloss image portion C (difference between the gloss values G1 and G2) is at least 20 or more from the viewpoint of human visual characteristics. In order to further improve the recognizability of the high gloss portion, it is preferable that the gloss contrast be 40 or more. That is, the gloss value G1 at a measurement angle of 60 ° after separation from the belt where the receiving layer B of the recording sheet P is present, and the gloss value G2 at a measurement angle of 60 ° after separation from the belt where there is no image receiving layer It is desirable that G1−G2 ≧ 20 (the glossiness of the toner image formed on the toner receiving layer is 20 or more higher than the glossiness of the toner image formed on the base material). Thereby, the contrast difference between high gloss and low gloss becomes large, and an image excellent in design and art can be provided.

  The pattern form of the receiving layer B provided on the surface of the recording sheet P is arbitrary. By changing the pattern of the screen film of silk screen printing to a desired one, it is possible to obtain another desired pattern as shown in FIGS. 9 and 10, for example. As shown in FIGS. 1, 9, and 10, the receiving layer B may be formed in the same pattern in a regular arrangement, a non-uniform arrangement, or a partial formation. The receiving layers B having different patterns may be mixed.

  By using the present invention, it is possible to form an arbitrary image having different glossiness on a recording sheet, and therefore, new characteristics and commercial properties different from conventional ones can be provided as an output product after image formation.

  It should be noted that the material, thickness, and fixing conditions of the recording sheet P in this embodiment are not necessarily limited to the exemplified values, and it is needless to say that the gloss value obtained varies depending on these conditions.

  Next, the structure which embossed the receiving layer is demonstrated.

  As shown in the schematic diagram of FIG. 11A, the recording sheet P of the present example was coated with a toner receiving layer B made of resin on the entire surface of a base paper (base material) A, As shown in the schematic diagram of b), the sheet is in a form subjected to embossing.

  By doing in this way, in the receiving layer B of the recording sheet P, the concave embossed part E and the convex embossed part G are scattered and formed.

  An image was formed using the recording sheet P in the embossed form.

  FIG. 12A is a schematic diagram of a state before fixing in which an unfixed toner image T is placed on the recording sheet P described above. An unfixed toner image T is formed on the embossing receiving layer B in both the convex embossed part G and the concave embossed part E.

  FIG. 6B is a schematic diagram of a post-fixing state in which the recording sheet P is fixed using the belt fixing device 106 described above. J schematically represents the post-fixing shape of the toner image portion corresponding to the convex embossed portion G of the receiving layer B, and K represents the post-fixing shape of the toner image portion corresponding to the concave embossed portion E of the receiving layer B. This is a schematic representation.

  The toner image portion formed at the convex embossed portion G is in close contact with the fixing belt 57 and is fixed and cooled. Therefore, the toner image portion is sufficiently melted and embedded in the receiving layer B. The receiving layer B and the fixed toner image portion J, which are fixed in a state where the toner image is embedded in the receiving layer B, coagulates to become a smooth surface following a mirror-like belt surface shape, and thus has excellent gloss. It becomes the image part. Further, the convex embossed portion G where there is no toner image is solidified following a mirror-like belt surface shape and becomes a smooth surface excellent in glossiness.

  On the other hand, the toner image portion formed at the concave embossed portion E is not sufficiently adhered to the fixing belt 57. Then, the toner at the concave embossed portion E cannot be sufficiently melted because sufficient heat is not supplied from the fixing belt 57. Further, the surface property of the fixing belt 57 cannot be sufficiently transferred to the toner image surface. As a result, at the concave embossed portion E, the toner image is not sufficiently embedded in the receiving layer B, and the surface of the fixed toner image becomes rough and low gloss. A portion where there is no toner image at the concave embossed portion E cannot obtain a sufficient gloss and becomes a low gloss portion.

  As a result, the high-gloss image portions and the low-gloss image portions are interspersed in the fixed toner image on the recording sheet P in accordance with the shape of the uneven embossment of the receiving layer B.

  Therefore, high-gloss images can be scattered partially or regularly, and an image excellent in design and art can be provided.

  The depth of the embossed unevenness depends on the basis weight of the recording sheet. Appear to be scattered, and becomes prominent when the thickness exceeds 100 μm. Accordingly, the depth (average value) of the concave portion relative to the convex portion is preferably set to 50 μm or more and 500 μm or less.

  Further, the fixing belt 57 cannot follow as the width of the concave portion becomes smaller. However, when the width becomes smaller than about 5 mm, the entire concave portion becomes low gloss. When the width of the concave portion increases, the fixing belt 57 may come into contact with the central portion of the bottom of the concave portion, but cannot follow the end portion of the bottom of the concave portion. Therefore, when the width is larger than about 5 mm, the central portion of the bottom of the concave portion is slightly glossy, but the end portion of the bottom of the concave portion is low glossy, so that a gloss difference from the convex portion occurs. Therefore, even when the width of the concave portion is large, a gloss difference from the convex portion occurs. Therefore, the width of the recess is preferably set to 1 mm or more and 5 mm or less.

  From the above, it can be said that the cause of the gloss difference due to unevenness is greatly influenced by the depth of the recesses. Further, as the hardness of the surface layer material of the fixing belt 57 is higher, the followability to the concave and convex portions is lowered, and thus the gloss difference tends to increase.

  Actually, the gloss of the toner surface after fixing formed on the convex embossed portion G and the concave embossed portion E having a depth of 100 μm with respect to the convex portion was measured in the same manner.

  As a result, a toner surface after fixing having a gloss value of 90 was similarly obtained at the convex embossed portion G, and a toner surface after fixing having a gloss value of 60 to 70 was obtained at the concave embossed portion E.

  FIG. 13 shows the result of the gloss value of the uneven portion. According to the shape of the emboss, the convex portion obtained a high gloss value, and the concave portion obtained a low gloss value.

  In this embodiment, when the angle of the recording sheet P is changed with respect to the line of sight of the person, the high-gloss image portion J partially emerges, and unlike a conventional image, a new image with high design and art is created. I was able to get it.

  The relationship between the gloss value G3 at the measurement angle of 60 ° after separation from the belt at the embossed convex portion of the recording sheet P and the gloss value G4 at the measurement angle of 60 ° after separation from the belt at the embossed concave portion is G3- It is desirable that G4 ≧ 20 (the glossiness of the toner image formed on the convex portion of the toner receiving layer is 20 or more higher than the glossiness of the toner image formed on the concave portion). Thereby, the contrast difference between high gloss and low gloss is increased, and an image excellent in artistic properties can be provided.

  Furthermore, in this embodiment, since the surface of the recording sheet is also uneven corresponding to the glossy part, it is possible to add new value not only to the visual sense but also to the tactile sense.

  By using the present invention, it becomes possible to form an arbitrary image with different glossiness and shape in a recording sheet, and therefore, it is possible to provide new characteristics and commerciality different from conventional ones as an output product after image formation. it can.

  The recording sheet P in the embossed form may be a sheet in which the surface is embossed after the toner receiving layer is formed on the surface of the recording material base. .

  In the above embodiment, the fixing device for fixing the unfixed toner image has a function as a smoothing device. However, the present invention is not limited to such a configuration. For example, a hypothetical applicator that presupposes an unfixed toner image on a recording sheet may be installed in the image forming apparatus, and the above-described smoothing device may be separately prepared as an optional unit that can be attached to and detached from the image forming apparatus. Absent. That is, in this case, the option unit is a component of the image forming system. Note that the above-described hypothetical dressing device is configured to exhibit a function as a fixing device for normal paper.

  Pa to Pd: first to fourth image forming units, 1: photosensitive drum, 2: drum charger, 107/108: recording material cassette, 7: transfer belt (recording material carrier), 8: polygon mirror, 9 : Registration roller, 10: Separation charger, 11: Selector, 110: Paper discharge tray, 111: Double-sided transport unit, 106: Fixing device (belt fixing device), 51: Fixing roller, 52: Pressure roller, 53: Separation Roller: 54: tension roller, 55: auxiliary roller, 56: cooling fan, 57: fixing belt, 58: heater, 59: heater, P: recording material, A: substrate (base paper), B: toner receiving layer, C: cross section of toner without receiving layer, D: cross section of toner with receiving layer, E: cross section of concave portion, G: cross section of convex portion

Claims (7)

  And a toner receiving layer made of a thermoplastic resin provided on the substrate and having a glass transition temperature of 40 ° C. or more and 80 ° C. or less, and the toner receiving layer has irregularities formed by embossing. An image receiving sheet for electrophotography, characterized in that a portion is formed.   2. The electrophotographic image-receiving sheet according to claim 1, wherein the depth of the concave portion of the toner-receiving layer is 50 to 500 [mu] m.   3. The electrophotographic image receiving sheet according to claim 1, wherein the width of the concave portion of the toner receiving layer is 1 mm or more and 5 mm or less.   4. The electrophotographic image receiving sheet according to claim 1, wherein the toner receiving layer is transparent.   An image forming system having a smoothing means for smoothing the convex portion of the toner receiving layer by heating and pressurizing the electrophotographic image-receiving sheet according to any one of claims 1 to 4, wherein the convex portion of the toner receiving layer is provided. An image forming system characterized in that the glossiness of an image formed in a portion is set to be 20 or more higher than the glossiness of an image formed in a recess.   The smoothing means includes a glossy belt for heating the electrophotographic image receiving sheet at the nip portion, a nip forming member for forming the nip portion between the belt, and the electrophotographic image receiving sheet that moves while being in close contact with the belt. The image forming system according to claim 5, further comprising a cooling unit that cools the image before separation.   7. The heating temperature by the smoothing means is 100 ° C. or more and 170 ° C. or less, the sheet conveying speed is 25 mm / sec or more and 75 mm / sec or less, and the pressing force is 245 N or more and 735 N or less. Image forming system.