JP4432665B2 - Electrophotographic transfer paper and image forming method - Google Patents

Description

  The present invention relates to an electrophotographic transfer paper used for forming an image by an electrophotographic method applied to a color copying machine, a color printer, and the like, and an image forming method using the same.

  Conventionally, as a method of forming a color image by an electrophotographic method, an electrostatic latent image is formed for each color by irradiating color separation light on a photoconductor, and the electrostatic latent image for each color is converted into Y (yellow). ), M (magenta), C (cyan) and other color toners are sequentially developed to form a color toner image for each color, and each time a toner image of each color is formed, it is superimposed and transferred onto the transfer member. A method of forming a color image by heating and fusing and fixing the toner image is known.

  In addition, the color toner images formed for each color are superimposed on the photosensitive member, not the transfer member, and the superimposed color toner images are collectively transferred onto the transfer member and fixed by heating and melting them. Then, when transferring the color image from the photosensitive member to the transfer member, the color toner image on the photosensitive member is once transferred on an intermediate transfer member made of a belt or the like, A method of transferring the superimposed color toner images from the intermediate transfer member onto the transfer member at once and further fixing by heating and melting is also included.

The color toner used in such a process is a binder resin in which various components such as a colorant composed of a dye or a pigment are mixed or dispersed, and the particle size thereof ranges from several μm to several tens of μm. It is about μm. As such a color toner receptor, a paper substrate such as plain paper, general printing paper, and coated paper is used, and the color toner layered on the substrate is heated and melted to form a substrate. A color image is formed by being fixed on the top (see Patent Document 1).
For example, unevenness of about 10 to 100 μm may be formed on the surface of the color image formed in this way, and the unevenness on the surface of the color image causes uneven glossiness of the image.

In order to improve the above problems, a method is known in which a thermoplastic transparent resin layer is provided on a substrate and a toner image is embedded in the transparent resin layer by a heat roller fixing device.
For example, a toner image is placed on the surface of an image transfer sheet having a glass transition temperature of 40 to 70 ° C. and having a transparent resin layer made of a crosslinked resin soluble in tetrahydrofuran, and the toner is embedded in the transparent resin layer by a belt-like fixing device. A toner image on a surface of an image transfer sheet coated with a thermoplastic resin (see Patent Document 2), and using a fixing device having a belt-like fixing member, the toner is applied to the transparent resin layer. A method of embedding (see Patent Documents 3 and 4) is known.

  There has also been proposed a transfer sheet that can obtain gloss matching without uneven gloss without using a fixing device having a belt-like fixing member (see Patent Document 5). In this transfer sheet, the average molecular weight (Mwa) of the transparent resin constituting the transparent resin layer provided on the surface thereof and the average molecular weight (Mwb) of the binder resin of the color toner have a relationship of Mwa−Mwb ≧ 10000. The melting inclination angle with the binder resin of the color toner at the fixing temperature of the transparent resin toner is adjusted to 40 degrees or less.

  Furthermore, the number average molecular weight (Mn) of the transparent resin constituting the transparent resin layer provided on the surface is in the range of 5000 to 20000, and the glass transition temperature is in the range of 30 to 85 ° C. Has been proposed (see Patent Document 6). In addition, a method has been proposed in which a plasticizer is blended in a thermoplastic resin layer, and a binder and solid components that form the layer at the time of fixing are softened so that toner is embedded in the thermoplastic resin layer (see Patent Document 7).

In the technique described in the above-mentioned patent document, when a color toner image is fixed on a transfer body, the color toner image is heated and melted while being pressed by a fixing member such as a heat roller, so that the surface of the electrophotographic transfer paper is fixed. Fixing is performed so as to be embedded in the provided transparent resin layer.
When an image is formed using these methods, the toner is embedded in the thermoplastic resin layer in the low image density region, and the smoothness of the entire image forming surface is increased and gloss is developed, but in the high image density region, The toner image cannot be completely embedded in the thermoplastic resin layer, and the image portion in the image forming surface is raised as compared with the non-image portion, resulting in a step (hereinafter referred to as “image step”). ”). Such an image step causes a sense of incongruity when viewed visually, and the gloss decreases due to the presence of the image step, and the gloss difference of the entire image forming surface increases.

As a method of eliminating such image level differences and gloss differences on the image forming surface, a porous coating layer (thermoplastic foamed resin layer) is provided on the support and toner is embedded in the voids on the surface of the porous coating layer. There has been proposed a method for eliminating a sense of incongruity caused by an image level difference and a gloss difference between an image portion and a non-image portion (see Patent Documents 8 to 11).
When an image is formed using these techniques, the toner is easily embedded in the voids on the surface of the porous coating layer at the time of fixing, so that the image level difference can be improved compared to a paper provided with a thermoplastic resin layer. A sense of incongruity and a difference in gloss caused by the step can be suppressed.
In this technique, the difference in gloss is suppressed by lowering the gloss itself in the image area and the non-image area in addition to improving the embedding property of the toner. Therefore, the gloss of the entire image forming surface tends to be slightly low, which may be inappropriate for creating a document that requires a higher gloss.

As another technique for providing a porous coating layer on a support, a laminated porous sheet in which two or more porous coating layers are provided on a support has also been proposed (see Patent Document 12). . However, in this technology, since two or more porous coating layers are provided, the heat capacity of the entire porous coating layer becomes very large. Therefore, depending on the toner used and fixing conditions, the fixing toner and the porosity In some cases, the coating layer was insufficiently melted and a glossy image could not be obtained.
That is, with a paper having a porous coating layer on the surface, the glossiness of the entire image forming surface may be improved, but the glossiness may be insufficient.

  Furthermore, an electrophotographic image-receiving sheet having a porous image-receiving layer having an average pore size of 0.01 to 1 μm has also been proposed (see Patent Document 13). However, with this technique, the average pore size of the porous image receiving layer is very small, and it is insufficient for embedding the toner inside the porous image receiving layer during fixing.

JP 63-92965 A Japanese Patent Laid-Open No. 5-127413 JP-A-5-216322 Japanese Patent Laid-Open No. 6-11982 Japanese Patent Laid-Open No. 10-221877 JP-A-11-160905 JP 2000-275891 A JP-A-9-171266 JP 11-282192 A Japanese Patent Laid-Open No. 2000-292961 JP 2002-123032 A JP-A-11-10762 JP 2003-21926 A

As described above, in an electrophotographic transfer paper having a porous resin layer such as a porous coating layer or a porous image receiving layer on its surface, the toner is not sufficiently embedded after fixing. For this reason, it is impossible to sufficiently suppress the occurrence of an image level difference, and it is also possible to obtain only an image with poor glossiness in both the image area and the non-image area.
An object of the present invention is to solve the above problems. That is, the present invention relates to an electrophotographic transfer paper which can satisfactorily embed toner in a thermoplastic foamed resin layer during fixing, has no gloss difference on the entire image forming surface, and can form a glossy image. It is an object of the present invention to provide an image forming method using the.

In order to achieve the above-described problems, the present inventors first made extensive studies on problems in the prior art.
Conventionally, an electrophotographic transfer paper having a thermoplastic resin layer as an image receiving layer is melted by heating and pressurizing the toner image with a heat roller when the toner image is fixed on a transfer body. It is fixed so as to be embedded in the resin layer on the paper surface. In this case, in the low density image area, the toner is embedded in the thermoplastic resin layer, so that the smoothness of the entire image forming surface is increased and gloss is developed.

  However, in the high-density image area, the toner cannot be completely embedded in the thermoplastic resin layer, and an image step is generated. In addition, glossiness varies depending on the type of toner used. For these reasons, when a high-density image is formed, the gloss difference becomes large between the non-image area and the image area, and also in the image area, resulting in an uncomfortable image.

  In addition, as described above, by forming an image using a paper having a porous coating layer having innumerable voids inside and on the surface of the thermoplastic resin layer, it is possible to reduce the image step and the gloss difference caused by this. There is a way to make it smaller. Compared to the conventional electrophotographic transfer paper having a thermoplastic image-receiving layer that does not have voids, this method dramatically reduces the image level difference or in-plane gloss difference. It tends to be inferior. This is because the gloss difference between the non-image portion and the image portion is achieved by reducing the gloss of the entire image forming surface. Further, from this, it is considered that the gap diameter of the gap in the non-image area does not change before and after fixing.

On the other hand, since the porous coating layer (thermoplastic foamed resin layer) is formed through a process of applying a foamed thermoplastic resin coating liquid onto the base material, the porous coating layer is formed. There are many fine voids on the surface of the layer. Then, during transfer, the toner enters the fine voids on the surface of the porous coating layer, and the porous coating layer is melted at the time of fixing, so that the image portion (toner image portion) is inside the porous coating layer. The effect of reducing the image level difference is obtained by embedding in the gap and closing the gap.
However, as described above, in the conventional electrophotographic transfer paper having the thermoplastic foam resin layer on the surface, the conventional electrophotographic transfer paper having the thermoplastic resin layer having no void is surely provided. Compared to the above, the image level difference or the in-plane gloss difference is remarkably reduced, but the overall glossiness is inferior.

  Based on the above-described knowledge, the present inventors have intensively studied the cause of the poor glossiness after fixing in a conventional electrophotographic transfer paper provided with a thermoplastic foam resin layer on the surface. As a result, when the surface of the image area after fixing was observed, uneven shapes due to the toner were observed. That is, from this result, it was found that the toner was not completely embedded in the thermoplastic foamed resin layer, and this caused a decrease in gloss of the image area.

  Further examination of the poor embedding of the toner in the thermoplastic foamed resin layer revealed that the inventors have affected the time taken for the viscosity of the thermoplastic foamed resin layer to decrease during fixing. I thought. In other words, the time during which the thermoplastic foamed resin layer is heated at the time of fixing is extremely short. Therefore, in order to sufficiently embed the toner in the thermoplastic foamed resin layer within such a short time, a short time is required at the time of fixing. It is necessary that the viscosity of the thermoplastic foam resin layer rapidly decreases with time. From this, the present inventors considered that it is important to use a crystalline resin having a large viscosity change with respect to a temperature change as a resin material constituting the thermoplastic foamed resin layer, and found the following invention. . That is, the present invention

<1>
In an electrophotographic transfer paper comprising a base material and a thermoplastic foamed resin layer mainly composed of a thermoplastic resin provided on at least one side of the base material,
The temperature at which the viscosity of the thermoplastic foamed resin layer becomes 1 × 10 ⁴ Pa · s is in the range of 60 ° C. or higher and 100 ° C. or lower, and a crystalline resin and an amorphous resin are contained in the thermoplastic foamed resin layer. It is included,
When the temperature when the viscosity of the thermoplastic foamed resin layer becomes 1 × 10 ⁴ Pa · s (η1) is T1, and the viscosity at a temperature T2 that is 5 ° C. higher than the temperature T1 is η2, the following equation (1) a transfer paper for electrophotography inclination R1 is characterized der Rukoto 0.15 or more represented.
Formula (1) R1 = (log (η1) −log (η2)) / (T1-T2)

<2>
<2> The electrophotographic transfer paper according to <1>, wherein the thermoplastic foamed resin layer has a viscosity of 1 × 10 ³ Pa · s or less in a range of 110 ° C. to 130 ° C.

<3>
Of the thermoplastic foam resin layer, when the viscosity at viscosity Ita3,130 ° C. at 1 10 ℃ η4, inclination R2 of the following formula (2) is characterized in that 0.05 or less <1 > Or <2> . The electrophotographic transfer paper according to <2> .
- formula (2) R2 = (log ( η3) -log (η4)) / 20

<4>
<1>-<3> The electrophotography according to any one of <1> to <3>, wherein an average diameter of voids existing on the surface of the thermoplastic foam resin layer surface is in a range of 1.5 μm to 80 μm. Transfer paper.

<5>
The ratio of the number of voids between all voids present on the surface of the thermoplastic foamed resin layer and voids having a diameter of 80 μm or more (number of voids having a diameter of 80 μm or more / total number of voids) is 20% or less < The transfer sheet for electrophotography according to any one of 1> to <4>.

<6>
The area ratio of voids existing on the surface of the thermoplastic foamed resin layer is in the range of 15% or more and 80% or less, for electrophotography according to any one of <1> to <5> Transfer paper.

<7>
The coating amount of the base per one surface of the thermoplastic foam resin layer (dry weight basis) is being in the range of 2 g / m ² or more 40 g / m ² or less <1> to the <6> The electrophotographic transfer paper according to any one of the above.

<8>
The electrophotographic transfer paper according to any one of <1> to <7>, wherein the thermoplastic foamed resin layer contains a release agent.

<9>
A latent image forming step for forming a latent image on the latent image carrier, a developing step for developing the latent image using an electrophotographic developer to form a toner image, and a transfer for transferring the toner image to a transfer target In an image forming method including a step and a fixing step of heat-pressing the toner image on the surface of the transfer object,
An image forming method, wherein the transfer target is the electrophotographic transfer paper according to any one of <1> to <8>.

<10>
<9> The image forming method according to <9>, wherein the fixing step is oilless fixing.

  As described above, according to the present invention, it is possible to provide an electrophotographic transfer paper capable of forming an image having no unevenness in the image and uniform glossiness, and an image forming method using the same.

(Electrophotographic transfer paper)
The electrophotographic transfer paper of the present invention (hereinafter sometimes abbreviated as “transfer paper”) includes a base material and a thermoplastic foamed resin layer mainly composed of a thermoplastic resin provided on at least one surface of the base material. And the thermoplastic foamed resin layer has a temperature when the viscosity of the thermoplastic foamed resin layer is 1 × 10 ⁴ Pa · s is in the range of 60 ° C. or more and 100 ° C. or less, and the thermoplastic foamed resin layer A crystalline resin and an amorphous resin are contained therein.

  Therefore, according to the present invention, the toner is satisfactorily embedded in the thermoplastic foamed resin layer provided on the surface of the substrate as the image receiving layer at the time of fixing, there is no gloss difference on the entire image forming surface, and glossiness is achieved. An electrophotographic transfer paper capable of obtaining an image can be provided.

The viscosity of 1 × 10 ⁴ Pa · s is a viscosity necessary for the toner to be sufficiently embedded in the thermoplastic foamed resin layer at the time of fixing, and needs to be satisfied within a range of 60 ° C. to 100 ° C. is there. This is because when such a viscosity is exhibited below 60 ° C., the storage property of the transfer paper in a high temperature environment is deteriorated. On the other hand, when the viscosity is higher than 100 ° C., softening / melting of the thermoplastic foamed resin layer is hardly promoted during fixing, and toner embedding becomes insufficient.

Further, the thermoplastic resin contained as the main component of the thermoplastic foamed resin layer needs to contain both a crystalline resin (crystalline thermoplastic resin) and an amorphous resin (amorphous thermoplastic resin). There is.
When the thermoplastic resin contained as the main component of the thermoplastic foamed resin layer is composed only of an amorphous resin, the viscosity of the thermoplastic foamed resin layer at the time of fixing is slow to decrease, so that the toner is in the thermoplastic foamed resin layer. May not be fully embedded in For this reason, an image level difference occurs, the formed image has poor glossiness, and the gloss of the entire image forming surface often becomes non-uniform.

  On the other hand, when the thermoplastic resin contained as a main component of the thermoplastic foamed resin layer is composed only of a crystalline resin, the viscosity of the thermoplastic foamed resin layer is significantly reduced during fixing, and the resin component is transferred into the substrate. By penetrating, the thickness of the thermoplastic foamed resin layer is reduced. For this reason, the amount of toner embedding necessary to suppress the occurrence of unevenness on the surface of the image due to the toner cannot be secured, an image level difference occurs, and the formed image has poor glossiness. The overall gloss tends to be uneven.

  Therefore, from the viewpoint described above, the ratio of the crystalline resin to the total resin components (crystalline resin + amorphous resin) is preferably in the range of 10% by mass or more and less than 100% by mass, and 30 to 90% by mass. % Is preferable, and a range of 50 to 80% by mass is particularly preferable.

The crystalline resin used in the present invention means a crystalline resin excluding a polymer material used as a mold release agent, which will be described later, and a resin that shows a sudden decrease in viscosity in the fixing temperature range. . In this respect, the melting point of the crystalline resin used in the present invention is preferably in the range of 60 to 120 ° C, and more preferably in the range of 70 to 100 ° C.
When the melting point of the crystalline resin is less than 60 ° C., the storage property of the transfer paper in a high temperature environment may be deteriorated. When the temperature exceeds 120 ° C., the viscosity of the thermoplastic foamed resin layer is slowly lowered at the time of fixing, so that the toner may not be sufficiently embedded in the thermoplastic foamed resin layer.

  In addition, the combination of the crystalline resin and the amorphous resin used in the present invention is preferably highly compatible with each other. The details of the crystalline resin and the amorphous resin used in the present invention will be described later.

As a characteristic of a thermoplastic foamed resin layer, it is preferable that the viscosity in the range of 110 degreeC-130 degreeC is 1 * 10 < ³ > Pa * s or less. When the viscosity of the thermoplastic foamed resin layer at 110 ° C. to 130 ° C. exceeds 1 × 10 ³ Pa · s, the embedding property of the toner may deteriorate due to the high viscosity of the thermoplastic foamed resin layer.
Accordingly, the viscosity of the thermoplastic foamed resin layer at 110 ° C. to 130 ° C. is more preferably 5 × 10 ¹ Pa · s to 1 × 10 ³ Pa · s, and more preferably 2 × 10 ² Pa · s to 1 ×. More preferably, it is 10 ³ Pa · s or less, and the smaller the value, the lower limit is not particularly limited.

Further, when the viscosity when the viscosity of the thermoplastic foamed resin layer becomes 1 × 10 ⁴ Pa · s (η1) is T1, and the viscosity at a temperature T2 that is 5 ° C. higher than the temperature T1 is η2, the following formula (1) in Ru der inclination R1 is 0.15 or more represented.
Formula (1) R1 = (log (η1) −log (η2)) / (T1-T2)

  When the slope R1 is less than 0.15, it takes time to lower the viscosity of the thermoplastic foamed resin layer at the time of fixing, and the toner may not be completely embedded in the thermoplastic foamed resin layer. The slope R1 is more preferably 0.18 or more, and further preferably 0.2 or more.

Furthermore, when the viscosity at 110 ° C. of the thermoplastic foamed resin layer is η3 and the viscosity at 130 ° C. is η4, the slope R2 represented by the following formula (2) is preferably 0.05 or less.
Formula (2) R2 = (log (η3) −log (η4)) / 20

  If the slope R2 exceeds 0.05, unevenness may occur in the viscosity of the thermoplastic foamed resin layer at the time of fixing, and the toner may not be uniformly embedded in the thermoplastic foamed resin layer. Note that the slope R2 is preferably 0.03 or less, and more preferably 0.02 or less.

Moreover, the flow tester (CFT-500 Shimadzu Corp. make) was used for the measurement of the viscosity of a thermoplastic foamed resin layer. For the measurement sample, the thermoplastic foamed resin layer of the electrophotographic transfer paper having a thermoplastic foamed resin layer formed on the surface is scraped off with a razor or the like, and the scraped-off resin is made to be in an absolutely dry state in advance. 2 g of a sampler made into a cylindrical shape was used.
The measurement conditions for the viscosity of the thermoplastic foamed resin layer were as follows: die (nozzle) diameter 0.5 mm, thickness 1.0 mm, extrusion load 10 kgf (98 N), initial set temperature 50 ° C., preheat time 300 seconds, temperature increase rate 1 It was set to a constant temperature increase of ° C./min.

On the other hand, the melting point of the crystalline resin contained in the thermoplastic foamed resin layer was measured by a differential scanning calorimeter (EXSTAR6000 DSC, manufactured by Seiko Instruments Inc.) using a sample prepared in the same manner as the above-described viscosity measurement.
The measurement of the melting point was carried out by accurately weighing a 10 mg measurement sample, using alumina as a reference, and raising the temperature from −50 ° C. to 100 ° C. at a temperature raising rate of 10 ° C./min.

The viscosity of the thermoplastic foamed resin layer can be adjusted by the characteristics of the amorphous resin and the blending amount thereof. For example, a crystalline resin having a melting point of about 80 ° C. (copolymerized crystalline polyester resin: synthesized using oxalic acid as an acid-derived component and ethylene glycol as an alcohol component at a ratio of 1: 1, weight average molecular weight: 12000) And an amorphous resin having a softening point of about 80 ° C. (Phoenix PE-723, manufactured by Futaba Fine Chemical Co., Ltd.) at a mass ratio of 7: 3, the melt viscosity of the mixed resin is When measured with a flow tester, a sudden drop in viscosity (melting of the crystalline resin) occurs from about 80 ° C. When the melting of the crystalline resin is completed, the characteristics of this mixed resin are dominated by the characteristics of the amorphous resin. Viscosity reduction rate becomes slow. Specifically, the decrease in viscosity at 90 ° C. is moderate (in this example, the viscosity at 90 ° C .: 4 × 10 ² Pa · s), which is close to the slope of the melt viscosity curve of the amorphous resin.
Thus, the temperature at which the decrease in viscosity is moderate can be changed by appropriately changing the blending amount of the amorphous resin.

In the present invention, the thermoplastic foamed resin layer means that a resin coating solution containing a crystalline resin and an amorphous resin is mechanically agitated to contain a large number of fine bubbles, and is then used as a base material. It is formed through a process of coating on and further drying, and is a layer having a void on the surface.
This void is a mark of bubbles on the surface of the thermoplastic foamed resin layer, and is different from fine scratches and dents on the surface of the thermoplastic foamed resin layer. Further, the size of the void, the area ratio of the void on the surface of the thermoplastic foam resin layer, and the like also affect the image after fixing.

The average diameter of the voids (average void diameter) existing on the surface of the thermoplastic foamed resin layer is preferably in the range of 1.5 μm or more and 80 μm or less.
When the average gap diameter is within the above range, the toner is embedded in the image portion, and the gap is filled in the non-image portion. If the average gap diameter is less than 1.5 μm, the toner may not be buried in the gap at the time of fixing, and the gloss of the image area may be lowered. When the average diameter of the voids exceeds 80 μm, the toner is buried in the voids at the time of transfer, but the voids are not completely blocked at the time of fixing, and remain as void marks after fixing.
The average void diameter is more preferably 2 μm or more and 60 μm or less, and the average void diameter is more preferably 3 μm or more and 50 μm or less.

The ratio of the number of voids between all the voids present on the surface of the thermoplastic foamed resin layer and voids having a diameter of 80 μm or more (number of voids having a diameter of 80 μm or more / total number of voids) is preferably 20% or less.
A void having a diameter of 80 μm or more is not likely to be completely closed after fixing, and there is a high possibility that irregularities remain as void marks on the surface of the non-image area and the image area. If it exceeds 20%, it may cause a decrease in gloss.
The value of the number of voids having a diameter of 80 μm or more / total voids is more preferably 5% or less, and still more preferably substantially 0%.

The area ratio of voids existing on the surface of the thermoplastic foamed resin layer (surface void area ratio) is preferably 15% or more and 80% or less, more preferably 20% or more and 70% or less, and further preferably 25% or more. 60% or less.
When the surface void area ratio is less than 15%, the toner is not sufficiently embedded in the void at the time of transfer, and the surface of the thermoplastic foamed resin layer may be uneven due to the toner and the gloss may be lowered. . Further, if the surface void area ratio exceeds 80%, it is difficult to form a thermoplastic foamed resin layer, and the strength of the thermoplastic foamed resin layer is lowered and the desired performance cannot be obtained. is there.

Here, since the shape of the void formed on the surface of the thermoplastic foam resin layer is not necessarily a perfect circle, the diameter of the void is converted into an equivalent circle diameter based on the area within the outline of the void obtained by the image analyzer. This is what we asked for. According to this, the ratio of the average void diameter and the number of voids having a diameter of 80 μm or more with respect to the total number of voids is obtained. Further, the average void diameter, the ratio of the number of voids with a diameter of 80 μm or more to the total number of voids, and the surface void area ratio were obtained by taking a photograph of the surface of the thermoplastic foamed resin layer using a scanning electron microscope or an optical microscope. The outline of the pores on the surface can be accurately drawn on a transparent film with a black pen or the like, and further measured using a drum scanner (trademark: Luzex III, manufactured by Nireco). The surface void area ratio can be calculated by the following equation (3).
Formula (3) Surface void area ratio (%) = (total area of void portions existing on the surface of the thermoplastic foam resin layer) / (total surface area of the thermoplastic foam resin layer surface) × 100

The coating amount of the base per one surface of the thermoplastic foamed resin layer is preferably at 2 g / m ² or more 40 g / m ² or less on a dry weight basis. If the coating amount is less than 2 g / m ² , the toner cannot be completely embedded in the thermoplastic foamed resin layer at the time of fixing, and the gloss may be lowered. When the coating amount is more than 40 g / m ² , the thickness of the thermoplastic foamed resin layer becomes excessive and may be easily damaged. The coating amount of the thermoplastic foamed resin layer is preferably 5 g / m ² or more and 30 g / m ² or less, more preferably 8 g / m ² or more and 20 g / m ² or less.

Next, the crystalline resin used in the present invention described above will be described in more detail.
The crystalline resin used in the present invention is not particularly limited as long as it satisfies the above-mentioned conditions, but is preferably a crystalline polyester resin.
The crystalline polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In the following description, in the polyester resin, the component that was an acid component before the synthesis of the polyester resin is referred to as “acid-derived component”, and the component that was the alcohol component before the synthesis of the polyester resin is referred to as “alcohol. "Derived component".

  Examples of the acid for forming the acid-derived constituent component include various dicarboxylic acids, but the acid-derived constituent component in the specific polyester resin is preferably an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid, and particularly an aliphatic dicarboxylic acid. In particular, a linear carboxylic acid is desirable. Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. 1,11-undecanedicarboxylic acid, etc., or lower alkyl esters and acid anhydrides thereof, but are not limited thereto. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like.

  In addition to the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid, it is preferable that components such as a component derived from a dicarboxylic acid having a double bond and a component derived from a dicarboxylic acid having a sulfonic acid group are contained. The component derived from a dicarboxylic acid having a double bond is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a double bond, in addition to a component derived from a dicarboxylic acid having a double bond. Components are also included. The dicarboxylic acid-derived constituent component having a sulfonic acid group is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a sulfonic acid group, in addition to a constituent component derived from a dicarboxylic acid having a sulfonic acid group. Components are also included.

  A dicarboxylic acid having a double bond can be suitably used in order to prevent hot offset at the time of fixing since the entire resin can be cross-linked using the double bond. Examples of such dicarboxylic acids include, but are not limited to, fumaric acid, maleic acid, 3-hexenedioic acid, and the like. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned.

  On the other hand, as an alcohol for becoming an alcohol-derived constituent component, an aliphatic diol is preferable, and a linear aliphatic diol having a chain carbon number of 7 to 20 is more preferable. Further, when a polyester is obtained by condensation polymerization with an aromatic dicarboxylic acid, the chain carbon number is preferably an odd number. When the chain carbon number is an odd number, the melting point of the polyester resin is lower than when the chain carbon number is an even number, and the melting point tends to be a value within the numerical range described later.

  Specific examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-heptanediol. 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, and the like, but are not limited thereto. .

  In the alcohol-derived constituent component, the content of the aliphatic diol-derived constituent component is 80 constituent mol% or more, and includes other components as necessary. As the alcohol-derived constituent component, the content of the aliphatic diol-derived constituent component is preferably 90 constituent mol% or more. When the content of the aliphatic diol-derived constituent component is less than 80 constituent mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability are deteriorated. May end up. Other components included as necessary include diol-derived components having double bonds and diol-derived components having sulfonic acid groups.

  Examples of the diol having a double bond include 2-butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like. Examples of the diol having a sulfonic acid group include 1,4-dihydroxy-2-sulfonic acid benzene sodium salt, 1,3-dihydroxymethyl-5-sulfonic acid benzene sodium salt, and the like.

  The method for producing the crystalline polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. For example, direct polycondensation, transesterification method, etc. Depending on the type, it will be manufactured separately. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1.

  The production of the crystalline polyester resin can be carried out at a polymerization temperature of 180 to 230 ° C., and the reaction is carried out while reducing the pressure in the reaction system as necessary to remove water and alcohol generated during condensation. If the monomer is not dissolved or compatible at the reaction temperature, a high boiling point solvent is added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. If there is a monomer with poor compatibility in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed may be condensed in advance before polycondensation with the main component. .

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium, alkaline earth metal compounds such as magnesium and calcium, metals such as zinc, manganese, antimony, titanium, tin, zirconium and germanium. Examples include compounds, phosphorous acid compounds, phosphoric acid compounds, and amine compounds.

  On the other hand, the amorphous resin used in the present invention is not particularly limited as long as it is a known amorphous thermoplastic resin. For example, a resin having an ester bond; a polyurethane resin; a polyamide resin such as a urea resin; a polysulfone resin A polyvinyl chloride resin, a polyvinylidene chloride resin, a vinyl chloride-vinyl acetate copolymer resin, a vinyl chloride-vinyl propionate copolymer resin; a polyol resin such as polyvinyl butyral; a cellulose resin such as an ethyl cellulose resin and a cellulose acetate resin; Polycaprolactone resin, styrene-maleic anhydride resin, polyacrylonitrile resin, polyether resin, epoxy resin, phenol resin; polyolefin resin such as polyethylene resin and polypropylene resin; copolymerization of olefins such as ethylene and propylene with other vinyl monomers Resins, and the like can be exemplified acrylic resin. These polymers may be used as a mixture or copolymer in combination of two or more.

The thermoplastic foamed resin layer provided on the surface of the transfer paper of the present invention may contain other components as necessary in addition to the above-described crystalline resin and amorphous resin, for example, a pigment. It may be.
Examples of the pigment include inorganic pigments such as zinc oxide, titanium oxide, calcium carbonate, silicate, clay, talc, mica, calcined clay, aluminum hydroxide, barium sulfate, lithopone, silica, colloidal silica, polystyrene, polyethylene, polypropylene, Organic pigments called plastic pigments such as epoxy resin, spheres such as styrene / acrylic copolymers, hollow spheres, confetti, donuts and flats, starch powder, cellulose powder, etc. can be used. It is not limited. In addition, these pigments can be used individually or in mixture of 2 or more types as needed.

  Furthermore, it is preferable that the thermoplastic foamed resin layer contains a release agent. By including a release agent, it is possible to prevent the transfer paper from being wound around the fixing roller at the time of fixing, and to easily realize so-called oil-less fixing in which fixing is performed without supplying oil from the fixing device side to the surface of the fixing member. It becomes possible.

As the release agent, waxes, higher fatty acids, higher alcohols, higher fatty acid amides and the like can be used. Examples of waxes include plant waxes such as carnauba wax and rice wax, petroleum waxes such as paraffin, microcrystalline, and petrolactam, and synthetic hydrocarbon waxes such as polyethylene wax.
Examples of higher fatty acids include stearic acid, oleic acid, palmitic acid, myristic acid, lauric acid, and examples of higher alcohols include lauryl alcohol, myristyl alcohol, stearyl alcohol, cetyl alcohol, and behenyl alcohol. Examples of the higher fatty acid amide include stearic acid amide, palmitic acid amide, methylene bisstearyl amide, and ethylene bisstearyl amide.

  The release agent is preferably blended in the thermoplastic foamed resin layer within a range of 0.1% by mass to 20% by mass. If the blending amount is less than 0.1% by mass, the effect as a release agent is insufficient, and the transfer paper may be wound around the heat roller during fixing. Further, when the blending amount exceeds 20% by mass, the amount of the release agent oozing out onto the surface of the thermoplastic foamed resin layer increases, and after the release agent oozes into the non-image area or image area after fixing. May remain.

  As a method for generating and dispersing bubbles (foaming method) in a resin coating solution used for forming a thermoplastic foam resin layer, for example, a stirrer having a stirring blade rotating while performing planetary motion, for example, generally used for emulsification dispersion and the like A stirrer such as a homomixer or cowless dissolver, or a device capable of dispersing and mixing air as fine bubbles by mechanically stirring a mixture of air and coating liquid continuously fed into a closed system, such as Gaston in the United States A continuous foaming machine such as a county company or a Stoke company in the Netherlands can be used, but is not particularly limited thereto.

You may add a foam stabilizer and a foaming agent to a resin coating liquid as needed. These are added in order to improve the stability of the bubbles in the resin coating solution in a state where the desired bubble-containing state cannot be obtained due to insufficient mechanical stirring ability or the bubbles are contained.
Specific examples of foam stabilizers and foaming agents that can be used are not particularly limited and include, for example, higher fatty acids such as stearic acid and palmitic acid, higher fatty acid salts such as sodium lauryl sulfate, ammonium stearate, and ammonium palmitate. Further, higher fatty acid modified products such as alkyl alkanolamides and sorbitan fatty acid esters are particularly suitable because they have a high effect of enhancing the foamability of the coating liquid and improving the dispersion stability of the bubbles.

In addition, there is no restriction | limiting in the selection of these foam stabilizers and a foaming agent, However, It is better to avoid the thing which inhibits the fluidity | liquidity of a coating liquid or may impair coating workability | operativity.
The blending amount of the foam stabilizer and the foaming agent is a solid content with respect to 100 parts by mass of a solid content (a thermoplastic resin, a pigment added if necessary) contained in the resin coating liquid. The range of 0-30 mass parts is preferable, and the range of 1-20 mass parts is more preferable. In addition, although it may mix | blend exceeding 30 mass parts, the effect of addition will be saturated and the effect of producing or stabilizing a bubble will become impossible further.

  The coating method for forming the thermoplastic foamed resin layer on the substrate is a known method such as Mayer bar method, Clavier roll method, roll method, reverse roll method, blade method, knife method, air knife method, extrusion method, cast method, etc. The method can be arbitrarily selected from these methods.

Base materials include non-wood pulp such as LBKP (hardwood bleached kraft pulp), NBKP (softwood bleached kraft pulp), LBSP (hardwood bleached sulfite pulp), NBSP (softwood bleached sulfite pulp), cotton pulp, waste paper pulp, GP ( Any conventionally known pulp such as ground pulp) or TMP (thermomechanical pulp) can be used.
As for the papermaking method, a general long-mesh multi-cylinder type, a round net single-cylinder type, a Yankee type or the like can be used as appropriate. In addition, the filler used for these is not particularly limited, and calcium carbonate such as heavy calcium carbonate, light calcium carbonate, chalk, and kaolin, calcined clay, biophyllite, sericite, talc, and other silicic acids. Inorganic fillers such as titanium dioxide and organic fillers such as urea resin and styrene can be used.

  The sizing agent is not particularly limited. Sizing agents such as rosin-based sizing agents, synthetic sizing agents, petroleum resin-based sizing agents, and neutral sizing agents can be used. A combination of an appropriate sizing agent such as sulfuric acid band and cationized starch, fiber and fixing agent. It can also be used. In addition, a paper strength enhancer, a dye, a pH adjuster, etc. may be added.

  In order to adjust the electrical resistance value to these base materials, inorganic substances such as sodium chloride, potassium chloride, calcium chloride, sodium sulfate, zinc oxide, titanium dioxide, tin oxide, aluminum oxide, magnesium oxide, alkyl phosphate ester salts, Organic materials such as alkyl sulfate ester salts, sodium sulfonate salts, and quaternary ammonium salts can be used alone or in combination.

  When the base material is subjected to the smoothing process, it is performed using a smoothing processing apparatus such as a normal super calendar, gloss calendar, or soft calendar. Moreover, you may carry out suitably by an on-machine or an off-machine, and the form of a pressurization apparatus, the number of pressurization nips, heating, etc. are suitably adjusted according to a normal smoothing processing apparatus.

  The transfer sheet for electrophotography of the present invention can obtain a good image even if it has a thermoplastic foamed resin layer formed by applying and drying a resin coating solution containing bubbles on the surface of the substrate. It is possible to further improve the smoothness of the surface by using a super calender configured by appropriately combining a metal roll and a resin roll, or a metal roll and a cotton roll, etc. it can. In addition, after coating, the semi-dried or dried sheet is brought into contact with a heated or non-heated cast drum with a mirror finish to further improve the surface smoothness of the thermoplastic foam resin layer. Also good.

  When coated paper is used as the substrate, the base paper is not particularly limited. For example, acidic paper having a papermaking pH of around 4.5, an alkaline filler such as calcium carbonate as a main component, and a papermaking pH of about 6 is weak. A paper substrate such as neutral papermaking having an acidity to about 9 weak alkalinity is used. The coated paper used as the substrate is a coated paper having a coating layer formed by coating a coating liquid mainly containing an adhesive and a pigment on at least one side.

  As the adhesive for the pigment coating layer, a water-soluble and / or water-dispersible polymer compound is used. For example, cationic starch, amphoteric starch, oxidized starch, enzyme-modified starch, thermochemically-modified starch, esterified starch. , Starches such as etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, natural or semi-synthetic polymer compounds such as gelatin, casein, soy protein, natural rubber, polyvinyl alcohol, isoprene, neoprene, polybutadiene, etc. Polyalkylenes such as polydienes, polybutene, polyisobutylene, polypropylene, and polyethylene, vinyl polymers such as vinyl halide, vinyl acetate, styrene, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, and methyl vinyl ether And copolymers, Len - butadiene, methyl methacrylate - synthetic rubber latex butadiene etc., polyurethane resins, polyester resins, polyamide resins, olefin - maleic acid resins, and synthetic polymer compounds such as melamine resin. Of these, one or more types are appropriately selected and used according to the required quality of the electrophotographic transfer paper.

  The blending ratio of the adhesive is preferably in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the pigment. When the blending ratio is less than 5 parts by mass, the surface of the base material is eroded by the resin coating liquid when the thermoplastic foam resin layer is further applied onto the pigment coating layer formed on the base material. Can not get a good glossy white paper. On the other hand, when the blending ratio exceeds 50 parts by mass, bubbles are generated when the pigment coating layer is applied, and the coated surface is roughened, so that good white paper glossiness cannot be obtained.

  Examples of pigments include heavy calcium carbonate, light calcium carbonate, kaolin, calcined kaolin, structural kaolin, delaminated kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, and silica. , Magnesium aluminosilicate, particulate calcium silicate, particulate magnesium carbonate, particulate light calcium carbonate, mineral pigments such as white carbon, bentonite, zeolite, sericite, smectite, polystyrene resin, styrene-acrylic copolymer resin, urea Resins, melamine resins, acrylic resins, vinylidene chloride resins, benzoguanamine resins, fine hollow particles thereof, through-hole type organic pigments, and the like can be used, and one or more of these can be used.

  In addition to these, various auxiliary agents such as surfactants, pH regulators, viscosity modifiers, softeners, gloss imparting agents, dispersants, flow modifiers, and anti-conductive agents are included in the coating liquid for the pigment coating layer. Agent, stabilizer, antistatic agent, cross-linking agent, antioxidant, sizing agent, fluorescent brightener, colorant, UV absorber, antifoaming agent, water-resistant agent, plasticizer, lubricant, preservative, fragrance, etc. However, it can also be used as needed.

The coating amount of the pigment coating layer is appropriately selected according to the purpose of use of the electrophotographic transfer paper of the present invention. Is preferably in the range of ² to 8 g / m ² in terms of dry mass.
As a coating method for forming a coating layer, a generally known coating apparatus such as a blade coater, an air knife coater, a roller coater, a reverse roller coater, a bar coater, a curtain coater, a die coater, a gravure coater, a Champlex coater, a brush coater, and a two-roller. Alternatively, a metering blade type size press coater, a bill blade coater, a short dwell coater, a gate roller coater, or the like is appropriately used.
The pigment coating layer may be formed on one or both sides of the substrate, and the coating layer may have a multilayer structure by providing one layer or two or more intermediate layers as required. In the case of double-sided coating or a multilayer structure, the coating liquids do not have to be the same or the same coating amount, and may be appropriately adjusted according to the required quality level. In addition, when a coating layer is provided on one side of the substrate, a synthetic resin layer, a coating layer made of an adhesive and a pigment, or an antistatic layer is provided on the back side to prevent curling, impart printability, and supply / discharge It is also possible to impart paper suitability and the like. Furthermore, it is of course possible to add various application suitability to the back surface of the substrate by post-processing such as adhesion, magnetism, flame retardancy, heat resistance, water resistance, oil resistance, and anti-slip.

  The base material having the pigment coating layer is finished by adjusting the water content to 3 to 10% by mass, preferably about 4 to 8% by mass, in a normal drying process or surface treatment process.

  Further, when the base material is subjected to the smoothing process, it is performed using a smoothing processing apparatus such as a normal super calendar, gloss calendar, soft calendar or the like. Moreover, you may carry out suitably by an on-machine or an off-machine, and the form of a pressurization apparatus, the number of pressurization nips, heating, etc. are suitably adjusted according to a normal smoothing processing apparatus. However, when used as the base material of the transfer paper of the present invention, the pressure load is weakened to achieve both low air permeability and high smoothness, the pigment particle size of the pigment coating layer is increased, and the air permeability is lowered. It is preferable to do.

  However, if the above smooth finish treatment is performed under excessive pressure, the resin wall surrounding the bubbles of the thermoplastic foam resin layer is destroyed, the coating layer is densified to reduce heat insulation and cushioning, Since the pores on the surface of the thermoplastic foamed resin layer may be destroyed and the excellent transfer performance of the thermoplastic foamed resin layer may be lost, it is necessary to sufficiently consider the processing conditions in the smooth finishing treatment.

The electrophotographic transfer paper of the present invention is preferably one whose composition is adjusted so that its surface electrical resistance is 8.0 × 10 ⁸ Ω or more at a temperature of 28 ° C. and a relative humidity of 85%.

(Image forming method)
Hereinafter, the image forming method will be described in detail.
The image forming method of the present invention is an image forming method using a known electrophotographic system, and is characterized in that the electrophotographic transfer paper of the present invention is used as a transfer target. The process itself of the image forming method is not particularly limited, but specifically, the image forming method described below is preferable.

  That is, a latent image forming step of forming a latent image on the latent image carrier, a developing step of developing the latent image with an electrophotographic developer to form a toner image, and transferring the toner image to a transfer target. Preferably, the method includes a transfer step and a fixing step in which the toner image transferred onto the transfer target is heat-pressed onto the transfer target. The fixing step is preferably performed by oilless fixing.

The oilless fixing is a fixing method in which fixing is performed without fixing a release agent such as oil on the surface of the fixing member at the time of fixing, and generally a release agent is applied to the surface of the fixing member from a conventional fixing device. This is a fixing method performed using a fixing device without supplying means. Further, in the image forming method as described above, other steps may be included as necessary in addition to the four steps.
According to oilless fixing, since no oil is used, roughness of the obtained image surface is suppressed and writing on the image surface is facilitated.

Further, the developer for electrophotography may be either a two-component system composed of toner and carrier, or a one-component system composed only of toner, and known toners and carriers can be used. .
For the binder resin, colorant, release agent and other additives constituting the toner, known materials can be used in appropriate combination. For example, as the binder resin, polyester resin or styrene-acrylic resin can be used. Can be used mainly. The toner production method is not particularly limited, and any known toner production method such as a pulverization method or a polymerization method may be used.

  Next, the image forming method of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus preferably used in the image forming method of the present invention.

  In FIG. 1, 1 is a heat fixing roller, 2 is a pressure roller, 3 is a heating source, 11 is a photosensitive member (latent image carrier), 12 is a roller charger, 13 is an exposure device, and 14a is a developer (cyan). , 14b is a developer equipped with a developer (magenta), 14c is a developer equipped with a developer (yellow), 14d is a developer equipped with a developer (black), and 14a is a developing device. , 15 is an intermediate transfer member, 16 is a cleaner, 17 is a light static eliminator, 18a, 18b and 18c are spindle rollers, 19 is a transfer roller, and 20 is a transfer target (electrophotographic transfer paper of the present invention). .

The image forming apparatus shown in FIG. 1 includes a roller charger 12, an exposure device 13, and cyan, magenta, yellow, and black developers around a photosensitive member 11 that can rotate in the direction of arrow R in a clockwise direction. The developing device 14 incorporating the developing devices 14a, 14b, 14c, and 14d, the belt-like intermediate transfer member 15, the cleaner 16, and the light neutralizer 17 are arranged in this order.
The intermediate transfer member 15 is stretched by support shaft rollers 18a, 18b, and 18c arranged on the inner peripheral surface thereof, and is rotatable in the direction of arrow P. The support roller 18 a is in pressure contact with the photoreceptor 11 via the intermediate transfer member 15. The support roller 18 c is in pressure contact with the transfer roller 19 via the intermediate transfer member 15.

  In addition, the contacted portion between the outer peripheral surface of the intermediate transfer member 15 and the transfer roller 19 allows the transfer target 20 to be inserted in the arrow Q direction. A heat roller fixing device including a heat fixing roller 1 and a pressure roller 2 in pressure contact with the outer peripheral surface of the intermediate transfer body 15 and the transfer roller 19 is disposed on the arrow Q direction side. The transferred body 20 that has passed through the contact portion between the heat transfer roller 1 and the pressure roller 2 and the contact portion between the outer peripheral surface of the intermediate transfer member 15 and the transfer roller 19 can be inserted in the arrow Q direction. .

  Image formation using the image forming apparatus shown in FIG. 1 is performed as follows. First, the surface of the photoconductor 11 rotating in the direction of arrow R is charged by the roller charger 12. A latent image is formed on the charged portion of the surface of the photoconductor 11 by exposing the surface of the photoconductor 11 with irradiation light L emitted from the exposure device 13 based on image information corresponding to each color of cyan, magenta, and yellow. The latent image formed on the surface of the photoconductor 11 is developed by developing units 14a, 14b, 14c, and 14d built in the developing device 14, and a toner image is formed for each color. The developed toner image is transferred onto the outer peripheral surface of the belt-like intermediate transfer member 15.

  The toner image transferred onto the outer peripheral surface of the intermediate transfer member 15 is transferred in contact with the support roller 18 c via the intermediate transfer member 15 as the intermediate transfer member 15 advances in the direction of arrow P. Move between and. When the toner image on the outer peripheral surface of the intermediate transfer member 15 passes through a contact portion (nip portion) between the support roller 18c and the transfer roller 19 that is in pressure contact with the intermediate transfer member 15, this nip. The portion is transferred onto the transfer target 20 inserted in the direction of arrow Q. The toner image transferred onto the transfer target 20 is fixed on the transfer target 20 when the transfer target 20 passes through the contact portion between the heat fixing roller 1 and the pressure roller 2 in the direction of arrow Q. An image is formed.

  The photosensitive member 11 transfers the toner image onto the outer peripheral surface of the intermediate transfer member 15 and then rotates in the direction of the arrow R. The toner remaining on the photosensitive member 11 is removed by the cleaner 16, and the photosensitive member 11 is moved onto the photosensitive member 11. The remaining residual charge is neutralized by the light neutralizer 17 to prepare for the next image formation.

  As the fixing device used in the image forming method of the present invention, a contact-type heat fixing device can be used, for example, a heat fixing roller having a rubber elastic layer on a cored bar and, if necessary, a fixing member surface layer, In addition to a heat roller fixing device comprising a pressure roller having a rubber elastic layer on a mandrel and optionally having a fixing member surface layer, and a combination of such a roller and a roller, two members Any of the above can use a combination of a roller and a belt having a heating and / or pressure function, or a combination of a belt and a belt.

  For the base material (core) of the fixing member, a material having excellent heat resistance, strong strength against deformation, and good thermal conductivity is selected. In the case of a roller type fixing device, for example, aluminum, iron, copper, etc. In the case of a belt-type fixing device, for example, a polyimide film, a stainless steel belt, or the like is selected. On the surface of the roller-type substrate, an elastic rubber layer usually made of silicone rubber, fluorine rubber or the like is provided on the surface.

  The fixing member may contain various additives depending on the purpose. For example, the fixing member contains carbon black, metal oxide, ceramic particles such as SiC, etc. for the purpose of improving wear resistance and controlling resistance. May be.

  Next, the fixing process will be described in detail with reference to the drawings. FIG. 2 is a schematic configuration diagram showing an example of a fixing device used in the fixing step of the image forming method of the present invention. In FIG. 2, 1 is a heat fixing roller, 2 is a pressure roller, 3 is a heating source, 4 is a surface layer of a fixing member, 5 is an elastic layer, 6 is a toner image, and 7 is an object to be transferred (for electrophotography of the present invention). Transfer paper). Reference numerals 1 and 2 shown in FIG. 2 have basically the same functions as reference numerals 1 and 2 shown in FIG.

The fixing device shown in FIG. 2 is a device in which a fixing member has a roller shape, and the basic configuration thereof includes a heat fixing roller 1 and a pressure roller 2 disposed opposite thereto. The heat fixing roller 1 includes a heating source 3 for heating inside, and at least one layer such as an elastic layer 5 is provided so as to enclose the heating source 3, and the outer peripheral surface of the elastic layer 5. Is provided with the fixing member surface layer 4 located on the outermost periphery.
Further, the pressure roller 2 includes a heating source 3 for heating inside, and includes the heating source 3, and is provided with at least one layer such as an elastic layer 5 positioned at the outermost periphery. The heating source 3 may not be provided inside the pressure roller 2. The heating source 3 is controlled by a temperature control device (not shown) so that a desired heating temperature is obtained.

  The contact portion between the heat fixing roller 1 and the pressure roller 2 allows the transfer body 7 on which the toner image 6 is formed on the surface contacting the heat fixing roller 1 to be inserted in the arrow S direction. The toner image 6 is fixed by being heated and pressurized when the transfer body 7 passes through the portion, and an image is formed on the surface of the transfer body 7.

  Around the heat fixing roller 1, if necessary, a cleaning member for removing toner attached to the surface of the heat fixing roller 1, and a nail (finger) for peeling the transferred object 7 from the surface of the heat fixing roller 1. Etc. may be arranged.

  The heat fixing roller 1 and / or the pressure roller 2 are preferably provided with an elastic layer 5 having a single layer or a laminated structure, and the thickness of the elastic layer 5 is within a range of 0.1 to 3 mm. Is preferable, and it is more preferable that it is in the range of 0.5 to 2 mm. The elastic layer 5 is made of heat-resistant rubber such as silicone rubber or fluorine rubber, and the rubber hardness is preferably 60 or less. The fixing member having the elastic layer 5 is advantageous in that the fixing member is deformed following the unevenness of the toner image 6 on the transferred body 7 and the smoothness of the image surface after fixing can be improved. is there. When the thickness of the elastic layer 5 exceeds 3 mm, the heat capacity of the fixing member increases, and it takes a long time to heat the fixing member to a desired temperature, and energy consumption may increase. . If the thickness of the elastic layer is less than 0.1 mm, if the thickness is too thin, the deformation of the fixing member cannot follow the unevenness of the toner image, resulting in uneven melting, and distortion of the elastic layer effective for peeling. May not be obtained.

  The present invention will be described more specifically with reference to the following examples, but of course the scope of the present invention is not limited thereto. In the examples, “parts” and “%” indicate “parts by mass” and “% by mass” unless otherwise specified.

Example 1
Using a commercially available high-quality paper (OK Prince Quality Oji Paper Co., Ltd., basis weight 157 g / m ² ) as a base material, a resin coating solution containing bubbles having the following composition was prepared, and immediately after foaming, applied using an applicator bar. To form a thermoplastic foam resin layer, and an electrophotographic transfer paper having a basis weight of 167 g / m ² was obtained. The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

[Preparation of resin coating solution]
Crystalline resin (crystalline polyester resin, Vylonal MD-1930, manufactured by Toyobo Co., Ltd., melting point = 93 ° C.): 85 parts by mass Amorphous resin (amorphous polyester resin, Finetex ES-675, Dainippon Ink Chemical Industries, Ltd., glass transition temperature = 60 ° C .: 15 parts by mass / foam stabilizer (higher fatty acid type, DC100A, manufactured by San Nopco): 12 parts by mass / thickener (carboxymethylcellulose, AG gum SG, No. 1 Ichi Kogyo Seiyaku Co., Ltd.): 2 parts by mass Release agent (polyether-modified silicone oil, KF-354L, manufactured by Shin-Etsu Chemical Co., Ltd.): 5 parts by mass (Product name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.) and mixed with air at a stirring speed of 1000 rpm and stirred to achieve a foaming ratio of 3 times. Was given. Here, the expansion ratio is a value obtained by dividing the mass of 100 ml of the resin coating solution (raw solution) before the foaming treatment by the mass of 100 ml of the resin coating solution containing bubbles after the foaming treatment.

[Various properties of thermoplastic foam resin layer]
Razor the thermoplastic foam resin layer of the resulting electrophotographic transfer paper, scraping the surface of the thermoplastic foam resin layer with a cutter blade, etc., and making it completely dry, the viscosity and melting point of the thermoplastic foam resin layer, etc. A sample for measuring the characteristics was used. The temperature at which the viscosity obtained by the flow tester of the thermoplastic foamed resin layer sample was 1 × 10 ⁴ Pa · s was 93 ° C., the slope R1 was 0.36, and the melting point measured by DSC was 90 ° C. These results are shown in Table 1.

(Example 2)
Using a commercially available cast coated paper (basis weight 157 g / m ^2, manufactured by Mirror Coat Platinum Oji Paper Co., Ltd.) as a base material, a resin coating liquid containing bubbles having the following composition was prepared, and immediately after foaming, an applicator bar was used. Coating was performed to form a thermoplastic foamed resin layer, and an electrophotographic transfer paper having a basis weight of 167 g / m ² was obtained. The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

[Preparation of resin coating solution]
Crystalline resin (crystalline polyester resin, crystalline polyester resin synthesized using the production method described in JP-A No. 2001-117259, melting point = 75 ° C.): 85 parts by mass Crystalline polyester resin, Phoenix PE-723, manufactured by Futaba Fine Chemical Co., Ltd., glass transition temperature = 50 ° C.): 15 parts by mass, foam stabilizer (higher fatty acid type, DC100A, manufactured by San Nopco): 10 parts by mass, thickener (Carboxymethylcellulose, AG gum SG, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 3 parts by mass Release agent (Polyether-modified silicone oil, KF-354L, manufactured by Shin-Etsu Chemical Co., Ltd.): 5 parts by mass Resin mixed with the above components Using a continuous foaming machine (trade name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.), the coating liquid is mixed with air at a stirring speed of 1000 rpm. The mixture was stirred and subjected to foaming treatment so that the expansion ratio was 3 times.

[Various properties of thermoplastic foam resin layer]
A thermoplastic foamed resin layer was collected in the same manner as in Example 1 and used as a sample for measuring characteristics. The temperature at which the viscosity obtained by the flow tester of the thermoplastic foamed resin layer sample was 1 × 10 ⁴ Pa · s was 75 ° C., the slope R1 was 0.27, and the melting point measured by DSC was 72 ° C. These results are shown in Table 1.

(Example 3)
Using a commercially available high-quality paper (OK Prince Quality Oji Paper Co., Ltd., basis weight 157 g / m ² ) as a base material, a resin coating solution containing bubbles having the following composition was prepared, and immediately after foaming, applied using an applicator bar. To form a thermoplastic foam resin layer, and an electrophotographic transfer paper having a basis weight of 167 g / m ² was obtained. The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

[Preparation of resin coating solution]
Crystalline resin (crystalline polyester resin, Vylonal MD-1930, manufactured by Toyobo Co., Ltd., melting point = 93 ° C.): 50 parts by mass Amorphous resin (amorphous polyester resin, Finetex ES-675, Dainippon Ink Chemical Industries, Ltd., glass transition temperature = 60 ° C .: 50 parts by mass / foam stabilizer (higher fatty acid type, DC100A, manufactured by San Nopco): 10 parts by mass / thickener (carboxymethylcellulose, AG gum SG, No. 1) Ichi Kogyo Seiyaku Co., Ltd.): 5 parts by mass Release agent (polyether-modified silicone oil, KF-354L, manufactured by Shin-Etsu Chemical Co., Ltd.): 5 parts by mass (Product name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.) and mixed with air at a stirring speed of 1000 rpm and stirred to achieve a foaming ratio of 3 times. Was given.

[Various properties of thermoplastic foam resin layer]
A thermoplastic foamed resin layer was collected in the same manner as in Example 1 and used as a sample for measuring characteristics. The temperature at which the viscosity obtained by the flow tester of the thermoplastic foamed resin layer sample is 1 × 10 ⁴ Pa · s is 96 ° C., the slope R 1 is 0.30, the slope R 2 is 0.04, and the melting point measured by DSC is 84 ° C. Met. These results are shown in Table 1.

Example 4
Using a commercially available cast coated paper (mirror coated platinum, manufactured by Oji Paper Co., Ltd., basis weight 157 g / m ² ) as a base material, a resin coating solution containing air bubbles having the following composition was prepared. A thermoplastic foamed resin layer was formed by coating, and an electrophotographic transfer paper having a basis weight of 167 g / m ² was obtained. The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

[Preparation of resin coating solution]
Crystalline resin (crystalline polyester resin, crystalline polyester resin synthesized using the production method described in JP-A No. 2001-117259 (equivalent to the crystalline polyester resin shown in Example 2), melting point = 75 ° C.): 30 parts by mass / amorphous resin (amorphous polyester resin, Phoenix PE-723, manufactured by Futaba Fine Chemical Co., Ltd., glass transition temperature = 50 ° C.): 70 parts by mass / foam stabilizer (higher fatty acid type, DC100A, manufactured by San Nopco): 10 parts by mass, thickener (carboxymethylcellulose, AG gum SG, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 4 parts by mass, release agent (polyether-modified silicone oil, KF-354L, Shin-Etsu Chemical) 8 parts by mass A resin coating liquid in which the above components are mixed is added to a continuous foaming machine (trade name: Turbo Whip TW-70, Aikosha Seisakusho Co., Ltd.). The mixture was stirred and mixed with air at a stirring speed of 1000 rpm, and subjected to foaming treatment so that the expansion ratio was 3 times.

[Various properties of thermoplastic foam resin layer]
A thermoplastic foamed resin layer was collected in the same manner as in Example 1 and used as a sample for measuring characteristics. The temperature at which the viscosity obtained by the flow tester of the thermoplastic foamed resin layer sample is 1 × 10 ⁴ Pa · s is 72 ° C., the slope R1 of the viscosity-temperature curve is 0.16, the slope R2 is 0.02, and measured by DSC. The melting point was 62 ° C. These results are shown in Table 1.

(Example 5)
Using a continuous foaming machine (trade name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.), a resin coating solution having the same composition as in Example 4 was mixed and stirred with air at a stirring speed of 3000 rpm, and foamed. Foaming was performed so that the magnification was 4 times. Subsequently, on the same substrate as used in Example 4, the resin coating liquid was applied immediately after foaming using an applicator bar so that the coating amount was 4 g / m ^2, and thermoplastic foaming was performed. A resin layer was formed, and an electrophotographic transfer paper having a basis weight of 161 g / m ² was obtained. The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

(Example 6)
Using a continuous foaming machine (trade name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.), a resin coating solution having the same composition as in Example 4 was mixed and stirred with air at a stirring speed of 300 rpm, and foamed. Foaming was performed so that the magnification was doubled. Subsequently, on the same substrate as used in Example 4, the resin coating liquid was applied immediately after foaming using an applicator bar so that the coating amount was 10 g / m ^2, and thermoplastic foaming was performed. A resin layer was formed to obtain an electrophotographic transfer paper having a basis weight of 191 g / m ² . The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

(Example 7)
Using a continuous foaming machine (trade name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.), the resin coating liquid having the same composition as in Example 4 was mixed and stirred with air at a stirring speed of 5000 rpm, and foamed. Foaming was performed so that the magnification was 4 times. Subsequently, on the same substrate as used in Example 4, the resin coating liquid was applied immediately after foaming using an applicator bar so that the coating amount was 10 g / m ^2, and thermoplastic foaming was performed. A resin layer was formed to obtain an electrophotographic transfer paper having a basis weight of 167 g / m ² . The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

(Comparative Example 1)
The foamed resin coating solution prepared in Example 1 was applied to a base material to form a thermoplastic resin layer, and an electrophotographic transfer paper having a basis weight of 167 g / m ² was obtained.

(Comparative Example 2)
Using a high-quality paper with a basis weight of 157 g / m ² as a base material (OK Prince fine quality, manufactured by Oji Paper Co., Ltd.), a resin coating solution containing air bubbles having the following composition was prepared, and an applicator bar was used immediately after foaming. Then, a thermoplastic foamed resin layer was formed to obtain an electrophotographic transfer paper having a basis weight of 167 g / m ² . The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

[Preparation of resin coating solution]
Amorphous resin (styrene acrylic resin, Joncrill 52, manufactured by Johnson Polymer Co., Ltd., glass transition temperature = 65 ° C.): 100 parts by mass Foam stabilizer (higher fatty acid type, DC100A, manufactured by San Nopco): 8 parts by mass・ Thickener (carboxymethylcellulose, AG gum SG, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 3 parts by mass. Release agent (polyether-modified silicone oil, KF-354L, manufactured by Shin-Etsu Chemical Co., Ltd.): 8 parts by mass. Using a continuous foaming machine (trade name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.), the resin coating liquid mixed with is mixed with air at a stirring speed of 1000 rpm and stirred to obtain a foaming ratio of 3 times. A foaming treatment was applied.

[Various properties of thermoplastic foam resin layer]
A thermoplastic foamed resin layer was collected in the same manner as in Example 1 and used as a sample for measuring characteristics. The temperature at which the viscosity obtained by the flow tester of the thermoplastic foamed resin layer sample is 1 × 10 ⁴ Pa · s is 98 ° C., the slope R1: 0.012 of the viscosity-temperature curve, and the glass transition temperature measured by DSC is 67 ° C. Met. These results are shown in Table 1.

(Comparative Example 3)
An electrophotographic transfer paper having a basis weight of 158 g / m ² was obtained in the same manner as in Example 1 except that the resin coating solution having the following composition was used, the foaming conditions were changed, and the coating amount was 1 g / m ² . The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

[Preparation of resin coating solution]
Crystalline resin (crystalline polyester resin, crystalline polyester synthesized using the production method described in JP-A-2001-117259, melting point = 53 ° C.): 80 parts by mass Amorphous resin (amorphous Polyester resin, Finetex ES-850, manufactured by Dainippon Ink and Chemicals, glass transition temperature = 42 ° C.): 20 parts by mass, foam stabilizer: (higher fatty acid type, DC100A, manufactured by San Nopco): 10 parts by mass・ Thickener (carboxymethylcellulose, AG gum SG, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 4 parts by mass. Release agent (polyether-modified silicone oil, KF-354L, manufactured by Shin-Etsu Chemical Co., Ltd.): 8 parts by mass. Using a continuous foaming machine (trade name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.), the resin coating liquid mixed with is mixed with air at a stirring speed of 1000 rpm. The mixture was stirred and subjected to foaming treatment so that the expansion ratio was 3 times.

[Various properties of thermoplastic foam resin layer]
A thermoplastic foamed resin layer was collected in the same manner as in Example 1 and used as a sample for measuring characteristics. The temperature at which the viscosity obtained by a flow tester of the thermoplastic foamed resin layer sample was 1 × 10 ⁴ Pa · s was 50 ° C., the slope R1 was 0.22, and the melting point measured by DSC was 48 ° C. These results are shown in Table 1.

(Comparative Example 4)
A resin coating solution containing bubbles having the following composition, change the foaming conditions, the coating weight of 45 g / except that m ² in the same manner as in Example 1 having a basis weight 202 g / m ² of transfer paper for electrophotography Got. The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

(Preparation of resin coating solution containing bubbles)
Crystalline resin (crystalline polyester resin, crystalline polyester synthesized using the production method described in JP-A No. 2001-117259, melting point = 133 ° C.): 85 parts by mass Amorphous resin (amorphous Polyester resin, Polyester WR-905, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., glass transition temperature = 78 ° C.): 15 parts by mass / foam stabilizer (higher fatty acid type, DC100A, manufactured by San Nopco): 10 parts by mass / increase Viscosity (Carboxymethylcellulose, AG Gum SG, Daiichi Kogyo Seiyaku Co., Ltd.): 4 parts by mass. Release agent (Polyether-modified silicone oil, KF-354L, Shin-Etsu Chemical Co., Ltd.): 10 parts by mass. Using a continuous foaming machine (trade name: Turbo Whip TW-70, manufactured by Aikosha Seisakusho Co., Ltd.), the resin coating liquid was mixed and mixed with air at a stirring speed of 1000 rpm. Stirring and foaming treatment was performed so that the expansion ratio was 3 times.

[Various properties of thermoplastic foam resin layer]
A thermoplastic foamed resin layer was collected in the same manner as in Example 1 and used as a sample for measuring characteristics. The temperature at which the viscosity obtained by a flow tester of the thermoplastic foamed resin layer sample was 1 × 10 ⁴ Pa · s was 135 ° C., the slope R1 was 0.17, and the melting point measured by DSC was 136 ° C. These results are shown in Table 1.

(Comparative Example 5)
In Example 1, it was produced in the same manner as in Example 1 except that the thermoplastic resin component of the resin coating solution was only crystalline resin and the coating amount was changed to 4 g / m ² . The void characteristics of the thermoplastic foam resin layer are shown in Table 1.

[Various properties of thermoplastic foam resin layer]
Razor the thermoplastic foam resin layer of the resulting electrophotographic transfer paper, scraping the surface of the thermoplastic foam resin layer with a cutter blade, etc., and making it completely dry, the viscosity and melting point of the thermoplastic foam resin layer, etc. A sample for measuring the characteristics was used. The temperature at which the viscosity obtained by the flow tester of the thermoplastic foamed resin layer sample was 1 × 10 ⁴ Pa · s was 93 ° C., the slope R1 = 0.36, and the melting point measured by DSC was 92 ° C. These results are shown in Table 1.

(Quality evaluation method)
Table 1 shows the evaluation results of the obtained electrophotographic transfer papers. The measurement method for each of these evaluations is as follows.

[Image formation]
The obtained electrophotographic transfer paper was evaluated by outputting an image in a thick paper 2 mode as a fixing condition by using DocuCenterColor 500 (Fuji Xerox Co., Ltd., deployment of oilless fixing mechanism similar to FIG. 2) having the same configuration as FIG. did. The fixing temperature was set to 180 ° C.

[Basis weight measurement method]
It was measured by the method of JIS P 8124.

[Measurement method of viscosity]
A flow tester (CFT-500 manufactured by Shimadzu Corporation) was used for measuring the viscosity of the thermoplastic foamed resin layer. For the measurement sample, the foamed resin layer of the electrophotographic transfer paper having the thermoplastic foamed resin layer is scraped off with a razor or the like, and the foamed resin layer that has been scraped off is dried in advance, and 1.2 g of the dried resin is sampled. It was made cylindrical. Measurement conditions were: die (nozzle) diameter 0.5 mm, thickness 1.0 mm, extrusion load 10 kgf (98 N), initial set temperature 50 ° C., preheat time 300 seconds, temperature increase rate 1 ° C./min. It was warm.

[DSC (Differential Scanning Calorimeter) Measurement Method]
It was measured with a differential scanning calorimeter (EXSTAR6000 DSC, manufactured by Seiko Instruments Inc.). The measurement method is to accurately weigh 10 mg of a measurement sample (collected by the same method as used for the above-described measurement of viscosity), use alumina as a reference, and increase the temperature from 10 ° C / min to -50 ° C to 100 ° C. The temperature was raised to ° C and measured.

[Measurement method for air gap]
On the surface of the thermoplastic foamed resin layer, the average void diameter, the ratio of the number of voids with a diameter of 80 μm or more to the total number of voids (the number of voids with a diameter of 80 μm or more / the total number of voids), and the surface void area ratio After taking a photo of the surface of the thermoplastic foamed resin layer using a microscope or optical microscope, the outline of the pores (voids) on the surface is accurately drawn on a transparent film with a black pen, etc. (Trademark: Luzex III, manufactured by Nireco Corporation).
In calculating the average void diameter and the number of voids having a diameter of 80 μm or more / the total number of voids, the shape of the void formed on the surface of the thermoplastic foamed resin layer is not necessarily a perfect circle. Based on the area in the outline of the void obtained by the analysis device, a value converted to an equivalent circle diameter was used. Further, the surface void area ratio was calculated using the above-described equation (3).

[Glossiness measurement method]
Based on the method of JIS Z 8741, a gloss measuring device (GM-26D type, manufactured by Murakami Color Research Co., Ltd.) was used to measure the glossiness of the image portion after fixing under the conditions of an incident angle and a light receiving angle of 60 degrees.

[Evaluation of uniformity of image gloss]
Color chart (S7) image samples of high-definition color digital standard image data (ISO / JIS-SCID JIS X 9201-1995 compliant, issued by the Japanese Standards Association) were prepared and confirmed with an image portion Δ gloss. Here, Δ gloss is a value represented by the following expression (4).
Formula (4) Δ gloss (%) = maximum glossy part (%) − minimum glossy part (%)
Moreover, the evaluation in Table 1 is based on the following evaluation criteria.

-Δ gloss evaluation criteria-
◎: Δ gloss value is less than 5% ○: Δ gloss value is 5% or more and less than 10% △: Δ gloss value is 10% or more but less than 20% ×: Δ gloss value is 20% or more

[Evaluation of fixing offset]
It was evaluated sensuously whether an offset occurred in the image after fixing. The evaluation criteria are shown below.
-Evaluation criteria for fixing offset-
○: No problem ×: Image part is missing (offset occurrence)

[Evaluation of image step]
The height difference at the boundary between the non-image portion and the image portion was evaluated as an image step using the surface of the non-image portion as a reference point. Here, the image level difference was obtained by measuring the level difference at the boundary portion between the 100% tertiary color fixed image portion and the non-image portion using an ultradeep shape microscope (VK-8000, manufactured by Keyence Corporation). The indicated value is an average value of the measured values at five locations.

  As apparent from the results in Table 1, according to the image forming method of the present invention, the toner embedding is good, a uniform and glossy color image can be formed, and it is extremely useful in practice. I understand.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus preferably used in an image forming method of the present invention. 1 is a schematic configuration diagram illustrating an example of a fixing device used in a fixing step of an image forming method of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal fixing roller 2 Pressure roller 3 Heat source 4 Fixing member surface layer 5 Elastic layer 6 Toner image 7 Transfer object (electrophotographic transfer paper)
DESCRIPTION OF SYMBOLS 11 Photoconductor 12 Roller-type charger 13 Exposure apparatus 14 Four-color developing device (14a, 14b, 14c, 14d)
15 Intermediate transfer member 16 Cleaner 17 Light neutralizer 18 Spindle roller (18a, 18b, 18c)
19 Transfer roller 20 Transfer object (electrophotographic transfer paper)

Claims (3)

In an electrophotographic transfer paper comprising a base material and a thermoplastic foamed resin layer mainly composed of a thermoplastic resin provided on at least one side of the base material,
The temperature at which the viscosity of the thermoplastic foamed resin layer becomes 1 × 10 ⁴ Pa · s is in the range of 60 ° C. or higher and 100 ° C. or lower, and a crystalline resin and an amorphous resin are contained in the thermoplastic foamed resin layer. It is included,
When the temperature when the viscosity of the thermoplastic foamed resin layer becomes 1 × 10 ⁴ Pa · s (η1) is T1, and the viscosity at a temperature T2 that is 5 ° C. higher than the temperature T1 is η2, the following equation (1) electrophotographic transfer paper inclination R1 is characterized der Rukoto 0.15 or more represented.
Formula (1) R1 = (log (η1) −log (η2)) / (T1-T2) 2. The electrophotographic transfer paper according to claim 1, wherein the thermoplastic foamed resin layer has a viscosity within a range of 110 ° C. to 130 ° C. of 1 × 10 ³ Pa · s or less. A latent image forming step for forming a latent image on the latent image carrier, a developing step for developing the latent image using an electrophotographic developer to form a toner image, and a transfer for transferring the toner image to a transfer target In an image forming method comprising: a step; and a fixing step in which the toner image is heat-pressed onto the surface of the transfer object.
An image forming method, wherein the transfer object is the electrophotographic transfer paper according to claim 1.

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