JP2011064850A - Transfer device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer device which can reduce the amount of toner adhered from a transfer belt to transfer rollers even if direct contact between the surface of the transfer belt and the surfaces of the transfer rollers occurs, and which prevents dirt on a backside of paper, deterioration of image quality, and image defects such as density reduction. <P>SOLUTION: The transfer device has: the transfer belt 40 which carries an image developed by a liquid developer; the rollers 41, 42 with the transfer belt wound around; and the transfer rollers 61 which has an elastic layer, has hardness as the first hardness, when measured with a load of 10 mgf by a nano-indenter from the peripheral side, and the IRHD hardness as the second hardness, when measured from the peripheral side, and which abut against the rollers through the transfer belt. Assuming that the nano-indenter hardness similarly measured from the transfer belt surface layer side with the transfer belt wound around the rollers is the third hardness, and the IRHD hardness similarly measured from the transfer belt surface layer side is thefourth hardness, the third hardness is smaller than the first hardness, and the fourth hardness is larger than the second hardness, as the relationship therebetween. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a transfer apparatus and an image forming apparatus that use an intermediate transfer belt in an electrophotographic system.

Conventionally, in a transfer device using an intermediate transfer belt (transfer belt), a transfer belt supported by a belt driving roller (backup roller) and carrying a toner image made of a liquid developer is passed through a transfer material. The transfer roller is brought into contact with the transfer roller, and the transfer roller and the belt driving roller are brought into pressure contact to form a transfer nip portion, and the toner image carried on the transfer belt is transferred onto the transfer material. As a transfer roller, it is known that an elastic material such as conductive rubber is used as described in Patent Document 1 [0056] in order to obtain good transfer properties. For example, as described in Patent Document 2 (Claim 9), a transfer belt is known in which a base layer, an elastic layer, and a surface layer are sequentially laminated, and a toner image is carried on the surface layer side.

However, in this type of transfer device, the transfer belt surface and the transfer roller surface may be in direct contact with each other without a transfer material. For example, (1) the case where the surface of the transfer belt and the surface of the transfer roller are in direct contact with each other without the transfer material in an area outside the paper width or the paper length where there is no transfer material such as paper. In such a case, a phenomenon occurs in which the toner particles in the image portion of the transfer belt are attracted toward the transfer roller by the transfer bias at the transfer nip portion. As a result, there is a problem in that the toner particles adhere to the transfer roller, and if the cleaning is insufficient, the paper back is stained.

In addition, (2) when performing double-sided printing, for example, toner particles transferred to the transfer material are pressed against the transfer roller when printing on the back surface of the transfer material, and the transfer roller is caused by the pressing force or transfer electric field. There is a problem that image defects such as deterioration of image quality and density reduction occur.

(3) A transfer roller is provided with a recess, a transfer material gripping member is provided in the recess, a transfer material is gripped and transferred during transfer, and a mechanism for peeling the transfer material after transfer is provided. It is known to improve the releasability and transfer efficiency of the transfer material. For example, when A3 size printing is performed after A size printing, it is outside the A4 size paper width or outside the paper length. In the area, there is a problem that the paper back stains occur as in (1).

JP-A-7-271198 Japanese Patent No. 3248455 specification

The present invention is intended to improve transfer efficiency in a transfer device and an image forming apparatus using a transfer belt, and even if the transfer belt surface and the transfer roller surface are in direct contact with each other, The amount of toner adhesion can be reduced, dirt on the back of the paper and degradation of image quality,
It is an object of the present invention to provide a transfer device and an image forming apparatus free from image defects such as density reduction.

The transfer device of the present invention comprises a transfer belt having at least three layers of a base layer, an elastic layer, and a surface layer, and carrying an image developed with a liquid developer;
A roller around which the transfer belt is wound;
Having an elastic layer, the hardness when measured at a load of 10 mgf from the peripheral surface side with a nanoindenter is the first hardness, and the IRHD hardness measured from the peripheral surface side is the second hardness, A transfer roller in contact with the roller via a transfer belt,
In a state where the transfer belt is wound around the roller, the hardness measured at the time of 10 mgf load from the surface layer side of the transfer belt by the nanoindenter is a third hardness, and the transfer belt is applied to the roller. When the IRHD hardness measured from the surface layer side of the transfer belt is the fourth hardness in the wound state,
3rd hardness <1st hardness 4th hardness> It has the relationship of 2nd hardness.

The transfer roller includes a cleaning member that comes into contact with a peripheral surface of the transfer roller.

The transfer roller has a recess formed in the axial direction of the peripheral surface of the transfer roller, and an elastic sheet support member disposed in the recess, and the elastic layer is supported by the elastic sheet supported by the elastic sheet support member. It is characterized by comprising.

The image forming apparatus of the present invention includes a latent image carrier on which a latent image is formed,
A developing section for developing the latent image with a liquid developer;
A transfer belt having at least three layers of a base layer, an elastic layer and a surface layer, onto which an image developed by the developing unit is transferred;
A roller around which the transfer belt is wound;
Having an elastic layer, the hardness when measured at a load of 10 mgf from the peripheral surface side with a nanoindenter is the first hardness, and the IRHD hardness measured from the peripheral surface side is the second hardness, A transfer roller in contact with the roller via a transfer belt,
In a state where the transfer belt is wound around the roller, the hardness measured at the time of 10 mgf load from the surface layer side of the transfer belt by the nanoindenter is a third hardness, and the transfer belt is applied to the roller. When the IRHD hardness measured from the surface layer side of the transfer belt is the fourth hardness in the wound state,
3rd hardness <1st hardness 4th hardness> It has the relationship of 2nd hardness.

A transfer unit that conveys the transfer material to a transfer nip formed by contact between the transfer belt and the transfer roller, and transfers the image to the first surface of the transfer material; and the first surface of the transfer material. A fixing unit for fixing the transferred image;
The transfer material on which the image is fixed by the fixing unit is conveyed, and the second surface, which is the surface opposite to the first surface of the transfer material, is conveyed so as to be in contact with the transfer belt constituting the transfer unit. A transport section to perform,
It is characterized by having.

In the transfer device and the image forming apparatus of the present invention, the nanoindenter hardness from the surface layer of the transfer roller is set higher than the nanoindenter hardness from the surface side of the transfer belt when the transfer belt is wound around the belt driving roller. By doing so, the toner particles in the liquid developer can be made difficult to adhere to the transfer roller, and the surface of the transfer roller can be kept clean. That is, the nanoindenter hardness at a load of 10 mgf indicates a hardness corresponding to an indentation depth of about several microns from the surface of the measurement sample, and shows an enveloping property with respect to toner particles having a particle size of about several microns. It is conceivable that, by increasing the hardness of the transfer roller, it is more difficult to adhere to the transfer roller as compared to the transfer belt.

Further, by making the IRHD hardness from the surface side of the transfer belt in a state of being wound around the belt driving roller larger than the IRHD hardness from the surface layer of the transfer roller, a transfer nip portion necessary for transfer can be secured. This is because the IRHD hardness is 160 from the surface of the measurement sample.
This indicates the hardness equivalent to the indentation depth of about a micron. By making the IRHD hardness measured from the surface side of the transfer belt larger than the IRHD hardness similarly measured from the surface of the transfer roller, the nip necessary for transfer It is considered that this can contribute to improvement of transfer efficiency. That is, the transfer device of the present invention adjusts the relationship between the layer configuration of the transfer belt and the layer configuration of the transfer roller, and reverses the magnitude relationship between the respective nanoindenter hardness and IRHD hardness, thereby improving transfer efficiency. In addition to the improvement, the amount of toner attached to the transfer roller can be reduced, and a transfer device and an image forming device free from image defects such as paper backside contamination, image quality deterioration, and density reduction can be obtained.

It is a figure which shows typically the 1st example of the transfer apparatus and image forming apparatus of this invention. It is a figure which shows typically the 2nd example of the transfer apparatus and image forming apparatus of this invention. It is a perspective view in the secondary transfer roller of the 2nd example. It is sectional drawing in the secondary transfer roller of a 2nd example. It is a partial cross section figure of the secondary transfer roller of the 2nd example. It is a figure which shows typically the 3rd example of the transfer apparatus and image forming apparatus of this invention. It is a perspective view of a transfer belt. It is sectional drawing of a transfer belt. It is a figure for demonstrating the hardness measurement method from the surface layer in the transfer belt in the state wound around the belt drive roller by the nanoindentation method. It is a load-displacement curve figure obtained by the nanoindentation method about the multilayer belt obtained in Example 8 of this invention. It is a hardness-displacement curve figure obtained by the nanoindentation method about the multilayer belt obtained in Example 8 of this invention, and is a figure which shows the relationship with the hardness (mgf / micrometer < ² >) at the time of 10 mgf (100 microN) load. .

Hereinafter, a transfer apparatus and an image forming apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing a first example of a transfer apparatus and an image forming apparatus according to the present invention. Developing devices 30Y, 30M, 30C, 3 for the image forming portions of the respective colors arranged in the center of the image forming device
0K is disposed in the lower part of the image forming apparatus, and the configuration of the transfer belt 40, the secondary transfer part (secondary transfer unit) 60, the fixing unit 90, and the like is disposed in the upper part of the image forming apparatus. In particular, since the fixing unit 90 is laid out above the transfer belt 40, the installation area of the entire image forming apparatus can be suppressed. In this embodiment,
Since the transfer material such as paper that has undergone secondary transfer in the secondary transfer unit 60 is sucked by the transfer material transport device 230, the suction devices 210 and 270, etc., it is transported to the fixing unit 90. Such a layout can be realized.

The developing devices 30Y, 30M, 30C, and 30K are configured so that the photoreceptors 10Y, 10M, 10C, and 10K, the corona chargers 11Y, 11M, 11C, and 11K,
Exposure units 12Y, 12M, 12C, 12K, etc., such as LED arrays, are provided. The corona chargers 11Y, 11M, 11C, and 11K are used to provide the photoreceptors 10Y, 10M, 10C, and 10
K is uniformly charged, and exposure units 12Y, 12M, 12C, and 12K are used to perform exposure based on the input image signal, and electrostatic latent images are formed on the charged photoreceptors 10Y, 10M, 10C, and 10K. Form.

The developing devices 30Y, 30M, 30C, and 30K are roughly illustrated as developing rollers 20Y, 20M, and 2
Developer containers (reservoirs) 31Y, 31M, 31C, 31K for storing liquid developers of respective colors consisting of 0C, 20K, yellow (Y), magenta (M), cyan (C), and black (K)
The liquid developer of each color is provided with anilox rollers 32Y, 32M, 32C, 32K, etc., which are application rollers for applying the liquid developers of the respective colors from the developer containers 31Y, 31M, 31C, 31K to the developing rollers 20Y, 20M, 20C, 20K. Photoconductors 10Y, 10 by liquid developer
The electrostatic latent images formed on M, 10C, and 10K are developed.

The transfer belt 40 is an endless belt, and is stretched around a driving roller 41 and a tension roller 42, and the photoreceptors 10Y, 10M are formed by primary transfer portions 50Y, 50M, 50C, and 50K.
It is rotationally driven by the drive roller 41 while abutting 10C, 10K. Primary transfer part 5
In 0Y, 50M, 50C, and 50K, the primary transfer rollers 51Y, 51M, 51C, and 51K are disposed opposite to each other with the photoconductors 10Y, 10M, 10C, and 10K interposed between the transfer belt 40 and the photoconductors 10Y, 10M, 10C, and 10K. The developed photoreceptor 10 with the contact position as the transfer position.
The toner images of each color on Y, 10M, 10C, and 10K are sequentially superimposed and transferred onto the transfer belt 40 to form a full-color toner image.

In the secondary transfer unit 60, a secondary transfer roller 61 is disposed opposite to the belt driving roller 41 with the transfer belt 40 interposed therebetween, and a cleaning device including a secondary transfer roller cleaning blade 62 is disposed. Then, at a transfer position where the secondary transfer roller 61 is disposed, transfer of a single-color toner image or a full-color toner image formed on the transfer belt 40 through a transfer material transport path L is performed. Transfer to material.

Further, on the downstream side of the transfer material conveyance path L, the first guide member 210 and the transfer material conveyance device 23 are arranged.
0 and the second guide member 270 are sequentially arranged to convey the transfer material to the fixing unit 90. In the fixing unit 90, a monochrome toner image transferred onto a transfer material such as paper or the like A full-color toner image is fused and fixed to a transfer material such as paper.

The tension roller 42 stretches the transfer belt 40 together with the belt driving roller 41 and the like, and the cleaning device including the transfer belt cleaning blade 49 is brought into contact with the tension roller 42 at a position where the tension roller 42 is stretched. Arranged and transfer belt 4
The remaining toner on 0 and the carrier are cleaned. The transfer belt 4
The tension roller 42 has a driving force for driving 0, and the belt driving roller 41
Can be used as a simple belt tension roller.

The transfer material is supplied to the image forming apparatus by a paper feeding device (not shown). The transfer material set in such a sheet feeding device is transferred one by one at a predetermined timing.
To be sent out. In the transfer material conveyance path L, the transfer material is conveyed to the secondary transfer position by the gate roller 101 and the transfer material guide 102, and the single color toner developed image or the full color toner developed image formed on the transfer belt 40 is used as the transfer material. Transcript. As described above, the transfer material subjected to the secondary transfer is further conveyed to the fixing unit 90 by the transfer material conveying means centering on the transfer material conveying device 230. The fixing unit 90 includes a heating roller 91 and a pressure roller 92 urged to the heating roller 91 side with a predetermined pressure. A transfer material is inserted between the nips, and the transfer material is placed on the transfer material. The transferred single-color toner image or full-color toner image is fused and fixed to a transfer material such as paper.

The liquid developer accommodated in the developer container 31Y is a generally used Iso.
low concentration (about 1-3 wt%) and low viscosity using par (trademark: exon) as carrier,
It is not a volatile liquid developer that is volatile at room temperature, but a non-volatile liquid developer that has high concentration and high viscosity and is non-volatile at room temperature. That is, the liquid developer in the present invention is a liquid solvent such as an organic solvent, silicon oil, mineral oil, or edible oil obtained by dispersing toner particles having an average particle diameter of 1 to 3 μm in which a colorant such as a pigment is dispersed in a thermoplastic resin. High viscosity (HAAKE RheoStress RS60) which is added together with a dispersant to a toner solid content concentration of about 15 to 25%.
0, the viscoelasticity when the shear rate at 25 ° C. is 1000 (1 / s) is 30 to 30
A liquid developer of about 0 mPa · s).

In the transfer belt 40, at least three layers of a base layer, an elastic layer, and a surface layer are sequentially laminated from an inner peripheral surface to an outer peripheral surface, an elastic layer is provided on the base layer, and a surface layer is further provided thereon. It has a layer structure. Such a transfer belt 40 is used by being stretched by a belt driving roller 41 and a tension roller 42 on the base layer side and transferring a toner image on the surface layer side. The outer peripheral surface of the belt driving roller 41 is treated with a urethane coat in order to improve friction. In addition, since the transfer belt 40 having elasticity has good followability and responsiveness to the surface of the transfer material, toner particles having a particularly small particle diameter are sent and transferred to the recesses of the transfer material during the secondary transfer. It is effective for.

Next, the secondary transfer roller 61 includes a conductive substrate, an elastic layer fixed to the entire outer peripheral surface, and a surface layer formed on the elastic layer. For example, a conductive urethane rubber layer having a thickness of 2 mm and a JISA hardness of 50 is fixed to the outer peripheral surface of a tubular base material. For example, a water-based fluororubber paint (manufactured by Daikin Industries, Ltd.) is formed on the outer peripheral surface of the elastic layer. “GLS-213F) is applied to form a surface layer having a thickness of 15 μm, and a resistive layer having a volume resistivity of about 1 × 10 ⁶ to 1 × 10 ¹¹ Ω · cm is formed.

In the present invention, the image forming apparatus shown in FIGS. 2 and 6 to be described later including the image forming apparatus shown in FIG. 1 has a common relationship between the transfer belt 40 and the secondary transfer roller 61.
The configuration of the transfer belt 40 used in FIGS. 2 and 6 and the relationship between the nanoindenter hardness and IRHD hardness of the transfer belt 40 and the secondary transfer roller 61 will be described later.

Next, FIG. 2 is a diagram schematically showing a second example of the transfer device and the image forming apparatus of the present invention.
1 is the same as the first example except that the secondary transfer roller 61 is different, FIG. 3 is a perspective view of the secondary transfer roller, and FIG. 4 is a cross-sectional view of the secondary transfer roller. FIG. 5 is a partial cross-sectional view of the secondary transfer roller.

As shown in FIGS. 2 to 5, the secondary transfer roller 61 has a transfer material gripping member 64, a gripping member receiving portion 65, and a concave portion 63 as a support portion for the peeling member 79. The recess 63 has 2
It extends in the axial direction of the next transfer roller 61. The secondary transfer roller 61 includes a rubber sheet 61c as an elastic member wound around the outer peripheral surface of an arc portion that is a contact portion 61g of the conductive substrate 61b with the transfer belt 40. A resistance layer is formed on the outer peripheral surface of the arc portion of the secondary transfer roller 61 by the rubber sheet 61c.

The rubber sheet 61c has a three-layer structure including a base material layer, an elastic layer, and a surface layer. The base material layer has a thickness of about 80 to 110 μm, and is formed using, for example, a polyimide resin or a polyimide amide resin, and has a tensile elastic modulus of 1000 MPa to 8000 MPa.

The elastic layer has a thickness of about 0.5 to 5 mm, and is formed using, for example, conductive urethane rubber and has a JISA hardness of 30 to 70. The surface layer has a thickness of about 5 μm to 25 μm.
For example, it is formed using a water-based fluororubber paint (“GLS-213F” manufactured by Daikin Industries, Ltd.) The volume resistivity of the rubber sheet 61c is 1 × 10 ⁶ to 1 × 10 ¹¹ Ω · cm.

Further, as shown in FIG. 5, the rubber sheet 61c has both end portions 61d and 61e fixed to the wall surfaces 61b1 and 61b2 in the recesses formed in the base material 61b, and the other portions are only wound. Thus, it is not bonded or fixed to the base material 61. For example, the plates 61h and 61j are extended in the direction of the rotating shaft 61a on both end portions 61d and 61e of the rubber sheet 61c, and screws 61
It is good to fasten to the base material 61b with k or a screw. The plates 61h and 61j are respectively provided with convex portions 61h1 and 61j1, and the convex portions 61h1 and 61j1 are recessed into the rubber sheet 61c, so that the plates 61h and 61j are firmly fixed. Rubber sheet 6
The fixing of both end portions 61d and 61e of 1c to the recess 63 is not limited to this, and other methods may be used.

As shown in FIG. 5, a transfer material gripping member 64 as a transfer material gripping portion and a gripping member receiving portion 65 on which the transfer material gripping member 64 is seated are disposed in the recess 63. Transfer material gripping member 6
4 is arranged along the axial direction of the secondary transfer roller 61, and an arbitrary number can be provided. Each transfer material gripping member 64 is formed of the same shape and / or the same size from a thin strip of metal. As an example, the transfer material gripping member 64 is formed by being bent into a crank shape. One end portion of the transfer material gripping member 64 is a fixed end portion 64 a, and the other end portion of the transfer material gripping member 64 is a gripping portion 64 b that contacts and separates from the gripping member receiving portion 65. The holding portion 64b holds the leading end portion Sa of the transfer material S with being held between the holding member receiving portion 65 and the holding member 64b. Further, the transfer material gripping member 64
Has a bent portion 64c formed between the fixed end portion 64a and the grip portion 64b.

The peripheral length of the secondary transfer roller 61 is the length of the transfer material S in the transfer material movement direction having the maximum length in the transfer material movement direction among the types of transfer materials S used in the image forming apparatus 1 of this example. It is set larger than this. More specifically, the peripheral length of the secondary transfer roller 61 excluding the width of the concave portion 63 in the rotation direction of the secondary transfer roller is set to be larger than the maximum length of the transfer material S in the transfer material moving direction. As a result, the toner image on the transfer belt 40 is reliably transferred to the transfer material S having the maximum length in the transfer material moving direction.

Next, FIG. 6 is a diagram schematically showing a third example of the transfer device and the image forming apparatus of the present invention.
2 differs from the second example shown in FIG. 2 in that the image forming apparatus in FIG. 2 is added with a configuration for printing on both sides of the transfer material.

As shown in FIG. 6, when printing on one side of a transfer material, the printed transfer material is transported in the direction described as “during single-sided printing” in the drawing to complete the printing. When performing double-sided printing on a material, once the transfer material printed on one side is transported in the direction indicated as “path for double-sided printing” in the figure, the tip of the transfer material is The direction described as “path” is changed, and the back surface of the transfer material is used as the printing surface, and is conveyed again to the secondary transfer unit 60 and printed on the back surface. To finish double-sided printing.

Next, the configuration of the transfer belt 40 shown in FIGS. 1, 2, and 6, the nanoindenter hardness of each of the transfer belt 40 and the secondary transfer roller 61 that characterize the present invention, and IR
It describes about the relationship of HD hardness.

As shown in FIG. 7, the overall shape of the transfer belt 40 is a substantially cylindrical seamless belt,
As shown in FIG. 8, the cross section has a three-layer structure in which a base layer 523, an elastic layer 525, and a surface layer 527 are sequentially stacked. As a base layer material constituting the base layer 523, a polyimide resin or a polyamideimide resin is preferable. Also, the thickness is 50 μm to 150 μm
The tensile modulus is 1000 MPa to 8000 MPa, and the surface electrical resistivity is 10 ⁶ Ω / □ to
It is preferably 10 ¹² Ω / □.

More preferably, the base layer 523 has a tensile elastic modulus of 2300 to 3500 MPa and a surface electrical resistivity of 10 ⁹ Ω / □ (1.0 × 10 ⁹ Ω / □ to 9.9 × 10). ⁹ Ω /
□> and the thickness is about 70 to 90 μm.

Next, the elastic layer 525 is preferably made of an elastomer. The elastic layer 525 has a thickness of 100 to 400 μm, preferably 200 to 300 μm, and a JIS A hardness of 20 ° to 50.
°, preferably 30 ° to 40 °.

Next, as a surface layer material constituting the surface layer 527, (1) a combination of a rubber latex and a curing agent containing 1 to 5 parts by mass of fluororubber with respect to 1 part by mass of the fluororesin, or ( 2) A combination of a water-based urethane resin containing a fluororesin and a silicon component and a curing agent may be mentioned.

(1) will be described. The rubber latex is a fluororubber latex containing fluororubber and a vulcanizing agent and, if desired, usual additives such as fillers, colorants, acid acceptors, vulcanization accelerators, co-vulcanizing agents or paint additives. , A fluororesin is blended.

The fluororesin includes polyvinylidene fluoride (PVdF), polychlorotrifluoroethylene (CTFE), polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE) and at least one other ethylenic copolymerizable therewith. And a copolymer with an unsaturated monomer.

The fluororubber is not particularly limited. For example, a vinylidene fluoride copolymer that contains vinylidene fluoride as a comonomer, a tetrafluoroethylene copolymer that contains tetrafluoroethylene as a comonomer, or an ethylene / hexafluoropropylene copolymer. Examples thereof include coalescence and phosphazene rubber. As the vulcanizing agent, a commonly used fluororubber vulcanizing agent can be used.

In rubber latex, it is good to contain fluororubber more than 1 mass part with respect to 1 mass part of fluororesin, and 5 mass parts or less, Preferably it is a ratio of 1.1 mass part-4 mass parts.

In the present invention, for example, “Daiel Latex” manufactured by Daikin Industries, Ltd. may be used. For example, “Daiel Latex GLS-213F” is a fluororubber latex containing 25% by mass of the above-described fluororubber and 25% by mass of a fluororesin and containing a colorant. “Daiel Latex GLS-213CR” is an uncolored fluororubber latex composed of 25% by mass of the above-mentioned fluororubber and 25% by mass of a fluororesin. further,"
Daiel Latex GL-252 ”is made of 50% by mass of the above-mentioned fluororubber and is commercially available as a fluororubber latex containing a colorant. In the present invention, it is preferable to adjust the content ratio of the fluororesin and the fluororubber by appropriately mixing the product numbers.

Next, (2) will be described. As a surface layer material constituting the surface layer 527, it may be composed of a water-based urethane resin containing a fluororesin and a silicon component and a curing agent. For example, when prepared using a urethane paint “TW805” manufactured by Japan Atison Co., Ltd. Good.

The surface layer 527 has a thickness after drying of 5 to 30 μm, preferably 10 to 15 μm. When the thickness of the surface layer is less than 5 μm, it is difficult to uniformly coat the elastic layer, and uneven coating tends to occur, and the surface layer is worn during continuous operation, resulting in defects such as film cracking and durability. This is not preferable because the properties are lowered. On the other hand, if it exceeds 30 μm, it becomes difficult to stably coat the coating film, and the followability to paper deteriorates, so the transfer efficiency deteriorates, and the embedding worsens on paper having a large roughness. It is not preferable.

The IRHD hardness of the surface layer alone is 60 or more, preferably 70-80. For the IRHD hardness of the surface layer alone, use a Wallace hardness meter {needle shape is spherical (φ0.395mm)}, and the depth when pressed with a pressing force of 15.6gf under the condition of 23 ° C, Used to convert to hardness, the resulting hardness is dimensionless. For example, hardness 50 is 160 μm
This corresponds to the indentation depth. The measurement sample has a film thickness of 500 μm or more and is measured on a plate having hardness such as iron.

If the IRHD hardness of the surface layer alone is less than 60, the shape retention of the surface layer is deteriorated. Also,
Since tack (adhesiveness) increases, transfer efficiency deteriorates. The upper limit of IRHD hardness is 100.

Although the layer configuration of the transfer belt 40 has been described above, in the present invention, the relationship between the nanoindenter hardness and the IRHD hardness in the pressure contact state between the transfer belt 40 and the secondary transfer roller 61 is the toner. We found that it affects the transfer of particles.
Since the transfer belt 40 is supported by the belt drive roller 41, the nanoindenter hardness and IRHD hardness from the surface layer side of the transfer belt 40 wound on the belt drive roller are low. Need to be measured. The belt drive roller has a urethane coating with a thickness of several microns on the surface of the steel tube, and the influence of the coating layer on the nanoindenter hardness is negligible, so place the transfer belt on a hard plate such as an iron plate. Measured.

The nano indenter hardness is measured using a micro hardness measuring device (nano indenter), and this device is composed of a transducer a and a diamond Berkovich indenter b having a regular triangle shape as shown in FIG. The displacement amount (indentation depth) is measured with an accuracy of nm by applying a load of mgf order to the surface of the multilayer belt. As a commercially available product, “ENT-2100” (triangular pyramid indenter, 115 degrees between ridges) manufactured by Elionix can be used. This apparatus measures the reaction force (mgf / μm ² ) from the measurement surface, and in the present invention, it measures the hardness HM (Martens hardness) at a load of 10 mgf. In each example described later, it is an average value of 5-point measurement. Further, the standard deviation at this time is a value that is smaller by one digit or more than the measurement result, and indicates the significance of the measurement. 1 mgf / μm ² = 10 MPa
1 mgf = 10 μN. The nanoindenter hardness of the transfer belt 40 at a load of 10 mgf is preferably 0.2 MPa to 2 MPa.

Further, as described above, the secondary transfer roller 61 has, for example, a thickness of 2 on the outer peripheral surface of the tubular base material.
A conductive urethane rubber layer having a thickness of 50 mm and a JISA hardness of 50 mm is fixed, and a water-based fluororubber paint is applied to the outer peripheral surface of the elastic layer to form a surface layer having a thickness of 15 μm, or the outer peripheral surface of a tubular base material Further, a rubber sheet is wound, and examples of the rubber sheet include a base layer having a thickness of 100 μm, an elastic layer having a thickness of 2 mm, and a surface layer made of a water-based fluororubber paint having a thickness of 15 μm. In such a secondary transfer roller 61, the nanoindenter hardness may be measured directly from the surface layer side. In the secondary transfer roller 61, the nanoindenter hardness is about 4.5 MPa.

For the IRHD hardness, the Wallace hardness meter {needle shape is spherical (φ0.395
mm)} and measuring the depth when pressed at a pressing pressure of 15.6 gf under the condition of 23 ° C., and then converting to hardness. In the transfer belt 40, the above measurement method is used for IR.
The HD hardness is 55 to 70, preferably 60 to 65.

Further, in the secondary transfer roller 61, a Wallace hardness tester {
The needle shape is spherical (φ0.395 mm)}, and the pressing force is 15.6 gf under the condition of 23 ° C.
After measuring the depth when pressed in, it may be converted to hardness. In the secondary transfer roller 61, the IRHD hardness is about 55.

In the present invention, the nanoindenter hardness from the surface layer of the transfer roller may be set higher than the nanoindenter hardness from the surface side of the transfer belt in a state where the transfer belt is wound around the belt driving roller. The difference is preferably increased by 2 mpa or more, so that the toner particles in the liquid developer can be made difficult to adhere to the transfer roller, and the surface of the transfer roller can be kept clean. This indicates that the nanoindenter hardness at the time of 10 mgf load indicates the hardness corresponding to the indentation depth of about several microns from the surface of the measurement sample, and shows the enveloping property with respect to toner particles having a particle size of about several microns. It is considered that by increasing the hardness of the transfer roller, it can be less likely to adhere to the transfer roller as compared to the transfer belt.

Further, the IRHD hardness from the transfer belt surface layer in a state of being wound around the belt drive roller may be set larger than the IRHD hardness from the transfer roller surface layer. The difference is preferably increased by at least 2 or more. Thereby, the transfer nip part required for transfer can be secured. The IRHD hardness indicates a hardness corresponding to an indentation depth of about 160 microns from the surface of the measurement sample, and the IRHD hardness measured from the surface side of the transfer belt is made higher than the IRHD hardness similarly measured from the surface of the transfer roller. As a result, the nip portion necessary for transfer can be enlarged, and transfer efficiency can be improved.

The transfer device of the present invention improves the transfer efficiency by adjusting the relationship between the layer configuration of the transfer belt and the layer configuration of the transfer roller, and reversing the magnitude relationship between the respective nanoindenter hardness and IRHD hardness. At the same time, the amount of toner adhering to the transfer roller can be reduced, and a transfer device and an image forming device free from image defects such as paper back stain, image quality deterioration, and density reduction can be obtained.

Further, the surface layer of the transfer belt 40 has a rubber latex and a curing agent containing more than 1 part by mass of fluororubber with respect to 1 part by mass of the fluororesin and 5 parts by mass or less, or fluororesin and silicon. By having a water-based urethane resin containing a component and a curing agent, it is possible to improve the transfer efficiency and the embedding rate in paper, and to achieve both the transfer efficiency and the embedding rate in paper Can be good.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention, the other physical property of the multilayer belt produced in the Example and the comparative example was measured as follows.

(1) Nanoindenter hardness A measurement example of surface hardness by the nanoindentation method is shown for the multilayer belt obtained in Example 7 below. The nanoindenter ("ION-210" manufactured by Elionix Co., Ltd.)
0 ”), a multilayer belt is set, and the load speed is 15 mgf / se so that the load change is constant.
The test load was 150 mgf, the number of divisions was 500 steps, the step interval was 20 msec, and the temperature was 32 ° C.

FIG. 10 shows the relationship between the obtained displacement vs. load. FIG. 10 shows the relationship between the load (mgf) and the displacement (μm) when (when the indenter is pressed against the multilayer belt surface) → (when the indenter is unloaded). From this figure, it can be seen that the displacement A when the load is 10 mgf is 2 μm.

The hardness (mgf / μm ² , HM, Martens hardness) is
HM = P / A
(P is the (maximum) load applied to the indenter, and A is the contact projection area between the indenter and the sample at that time.)
As shown in FIG. 11, using this apparatus, the displacement (μm) v
An s hardness (mgf / μm ² ) curve can be obtained. From FIG. 11, the hardness (B) corresponding to the displacement A (2 μm) is obtained, and the HM hardness at a load of 10 mgf (100 μN) is 0.48M.
It turns out that it is Pa.

(2) Tensile modulus: measured according to JISK7113. The tensile elastic modulus of the surface layer and the base layer is obtained by pouring the materials of the examples and comparative examples onto a silicon rubber mold, and drying at room temperature.
It measured using the sheet | seat produced by making it harden | cure on the same conditions as the hardening conditions of an Example and each comparative example. Measured from the linear portion of the 50mm stress curve between 10mm wide chucks.

(3) Surface resistivity: “HIRESTA UPMCP-H” manufactured by Dia Instruments Co., Ltd.
T450 type "was measured using a URS probe under the conditions of an applied voltage of 250 V and a measurement time of 10 seconds. The measurement environment is a temperature of 23 ° C. and a relative humidity of 55%.

(4) Volume resistivity: “HIRESTA UPMCP-H manufactured by Dia Instruments Co., Ltd.
T450 type "was measured with a URS probe under the conditions of an applied voltage of 250 V and a measurement time of 10 seconds. The measurement environment is a temperature of 23 ° C. and a relative humidity of 55%.

(5) JIS A hardness of elastic layer; measured according to JIS K6253 (1993),
Type A was used.

(Application to the image forming apparatus shown in FIG. 1)
(Preparation of transfer belt 40)
(1) Preparation of base layer-Polyamideimide varnish synthesized by a known method from trimellitic acid and diphenylmethane diisocyanate-100 parts by mass-Carbon black (furnace black)-7.0 parts by mass-Dispersant ... 0.1 parts by mass are uniformly mixed in a bead mill, while rotating the cylindrical mold, the nozzle is brought into contact with the outer surface of the mold, and the base layer material is quantitatively supplied from the nozzle while the nozzle is The material was applied by moving it at a constant speed in the direction of the axis of rotation of the mold. Next, while rotating the mold, 300 ° C
The material was cured by gradually heating and cooling until a base layer having a thickness of 90 μm was formed. The tensile elastic modulus was 2300 MPa.

(2) Production of elastic layer The elastic layer material is shown in Table 1 below. The components contained in the curing agent shown in Table 1 were first mixed at the ratio shown in Table 1, and the obtained curing agent and the main agent were mixed at the ratio shown in Table 1 to prepare an elastic layer material. This material was coated on the base layer using the same apparatus as that used for the base layer preparation to form an elastic layer. Next, the belt coated with the elastic layer material on the base layer was heated at 150 ° C. for 1 hour to cure the elastic layer. The elastic layer had a thickness of 250 μm and a JISA hardness of 30.

-Main agent: terminal prepolymer with NCO content of 6.9% obtained from polypropylene glycol and tolylene diisocyanate (manufactured by Sumika Bayer Urethane Co., Ltd.)
・ Acclaim 4220: Polypropylene glycol (manufactured by Sumika Bayer Urethane Co., Ltd.)
Ecure 300; dimethylthiotoluenediamine (manufactured by Albemarle)
Antistatic agent: “Sanconol PEO-20R” manufactured by Sanko Chemical Co., Ltd. (aqueous solution in which lithium-bis (trifluoromethanesulfonyl) imide is dissolved in polyol)
Antifoaming agent: “Floren AC326F” manufactured by Kyoeisha Chemical Co., Ltd.

(3) Preparation of surface layer Next, the surface layer of the following composition was formed on the elastic layer on the base layer obtained above, and it was set as the transfer belt of Examples 1-2 and Comparative Example 1.

Example 1
・ “Daiel Latex GLS-213CR” manufactured by Daikin Industries, Ltd. (uncolored fluororubber latex consisting of 25% by mass of fluororubber and 25% by mass of fluororesin)
... 40% by mass
・ “Daiel Latex GL-252CR” manufactured by Daikin Industries, Ltd. (Fluororubber 5
Uncolored fluororubber latex consisting of 0% by mass) ... 60% by mass
・ Curing agent ("Daiel Latex GL-200" manufactured by Daikin Industries, Ltd.)
... 1.5% by mass (outer hook)
To obtain a surface layer material containing 4 parts by mass of fluoro rubber with respect to 1 part by mass of the fluororesin. The obtained surface layer material was coated on the elastic layer obtained above with an electrostatic coating gun. After drying, it was cured in an oven at 150 ° C. for 60 minutes to form a surface layer having a thickness of 14.8 μm, and a transfer belt was produced. The surface layer thickness was measured using a dial gauge. The hardness of the surface layer alone (IRHD) was 68.

Moreover, the hardness measured at the time of 10 mgf load with a nanoindenter from the surface side of the transfer belt on the iron plate was 0.41 MPa, and the micro hardness (IRHD) was 60.

Further, the surface resistivity (logΩ / □, the same applies hereinafter) of the transfer belt on the surface layer side is 10.0, and the surface resistivity (logΩ / □, the same applies hereinafter) on the base layer side is 10.0. The volume resistivity (log Ω · cm, the same applies hereinafter) was 8.5.

(Example 2)
・ “Daiel Latex GLS-213CR” manufactured by Daikin Industries, Ltd. (uncolored fluororubber latex consisting of 25% by mass of fluororubber and 25% by mass of fluororesin)
... 80% by mass
・ “Daiel Latex GL-252CR” manufactured by Daikin Industries, Ltd. (Fluororubber 5
Uncolored fluororubber latex consisting of 0% by mass) ... 20% by mass
・ Curing agent ("Daiel Latex GL-200" manufactured by Daikin Industries, Ltd.)
... 5% by mass (outer)
To obtain a surface layer material containing 1.5 parts by mass of fluoro rubber with respect to 1 part by mass of the fluororesin. The obtained surface layer material was coated on the elastic layer obtained above with an electrostatic coating gun. After drying, it was cured in an oven at 150 ° C. for 60 minutes to form a surface layer having a thickness of 14.2 μm, and a transfer belt of Example 2 was produced. Further, the hardness (IRHD) of the surface layer alone was 94.

The hardness measured at the time of 10 mgf loading with a nanoindenter from the surface side of the transfer belt on the iron plate was 1.75 MPa, and the micro hardness (IRHD) was 65.

Further, the surface resistivity on the surface layer side of the transfer belt was 10.0, the surface resistivity on the base layer side was 10.0, and the volume resistivity was 8.5.

(Comparative Example 1)
As the elastic layer, the elastic layer material shown in Table 1 above was prepared, applied on the base layer described above, and heated at 150 ° C. for 1 hour to cure the elastic layer. Elastic layer thickness is 600μm, J
The ISA hardness was 30.

On this elastic layer, a water-based fluororubber paint (“GLS-213F” manufactured by Daikin Industries, Ltd.) was applied with an electrostatic coating gun to form a surface layer, which was dried in an oven at 150 ° C. for 60 minutes,
A transfer layer was prepared by forming a surface layer having a thickness of 20 μm. The surface layer thickness was measured using a dial gauge. Further, the hardness (IRHD) of the surface layer alone was 98.

The hardness measured at the time of 10 mgf loading with a nanoindenter from the surface side of the transfer belt on the iron plate was 5.1 MPa, and the micro hardness (IRHD) was 44.

Further, the surface resistivity on the surface layer side of the transfer belt was 10.0, the surface resistivity on the base layer side was 10.0, and the volume resistivity was 8.5.

In the image forming apparatus shown in FIG. 1, the belt driving roller 41 has a steel diameter of 65.
It was a roller of mm, and the surface was subjected to urethane coating treatment of several μm.

In addition, the secondary transfer roller 61 is provided with a conductive urethane rubber layer (JISA hardness 50 °) having a thickness of 2000 μm directly fixed with an adhesive without providing a base layer on the surface of the steel roller, and an elastic layer thereof. A water-based fluororubber paint (“GLS-213F” manufactured by Daikin Industries, Ltd.) having a thickness of 15 μm is provided as a surface layer, and the hardness measured at the time of 10 mgf load by a nanoindenter from the surface layer side is 4 .5 MPa, and micro hardness (IRHD
) Was 55. The surface resistivity on the surface layer side was 10.0, and the volume resistivity was 7.0.

The obtained secondary transfer roller 61 was brought into contact with the belt driving roller via the transfer belt 40. The load at the time of contact can be 10 to 100 kgf, but in the image forming apparatus of FIG.
kgf and a desired nip width of 5 mm.

The results of the physical properties of the transfer belt and the secondary transfer roller of each example and the amount of toner attached to the secondary transfer roller 61 obtained when the image forming apparatus of FIG. 1 is driven under the above conditions are shown below. Shown in the table below.

The toner adhesion amount on the transfer roller is an OD value obtained by measuring the optical density on the surface of the transfer roller after printing 10,000 sheets with an optical density measuring device “X-Rite”. In the comparative example, solid content was observed on the surface of the transfer roller, but in the examples, the amount of the back surface of the paper was not dirty.

Further, the transfer efficiency of the comparative example was 89%, whereas that of Example 1 was 96%, and it was found that the transfer efficiency of the present invention was superior to that of the comparative example. The transfer efficiency is defined as the image density on the transfer belt before transfer being OD1, and the toner density remaining on the belt after transfer being O.sub.1.
When it was set to D2, it calculated as {(OD1-OD2) / OD1} * 100 (%). Then, the efficiency was measured while changing the transfer bias, and the result at the transfer bias when the efficiency was maximum was adopted. Moreover, it is the transfer efficiency which used coated paper ("Ultra Satin Kanfuji 127.9g" by Oji Paper Co., Ltd.) as a transfer material.

(Application to the image forming apparatus shown in FIG. 2)
(Preparation of transfer belt 40)
After the base layer and the elastic layer in the transfer belt were produced in the same manner as in the image forming apparatus in FIG.

(Example 3)
・ “Daiel Latex GLS-213CR” manufactured by Daikin Industries, Ltd. (uncolored fluororubber latex consisting of 25% by mass of fluororubber and 25% by mass of fluororesin)
... 80% by mass
・ “Daiel Latex GL-252CR” manufactured by Daikin Industries, Ltd. (Fluororubber 5
Uncolored fluororubber latex consisting of 0% by mass) ... 20% by mass
・ Curing agent ("Daiel Latex GL-200" manufactured by Daikin Industries, Ltd.)
... 1.5% by mass (outer hook)
To obtain a surface layer material containing 1.5 parts by mass of fluoro rubber with respect to 1 part by mass of the fluororesin. The obtained surface layer material was coated on the elastic layer obtained above with an electrostatic coating gun. After drying, it was cured in an oven at 150 ° C. for 60 minutes to form a surface layer having a film thickness of 15.3 μm, and a transfer belt was produced. The film thickness was measured using a dial gauge. The IRHD hardness was 89.

Further, the hardness measured at the time of 10 mgf loading with a nanoindenter from the surface side of the transfer belt on the iron plate was 1.50 MPa, and the micro hardness (IRHD) was 61.5.

Further, the surface resistivity on the surface layer side of the transfer belt was 10.0, the surface resistivity on the base layer side was 10.0, and the volume resistivity was 8.5.

Example 4
・ “Daiel Latex GLS-213CR” manufactured by Daikin Industries, Ltd. (uncolored fluororubber latex consisting of 25% by mass of fluororubber and 25% by mass of fluororesin)
... 40% by mass
・ “Daiel Latex GL-252CR” manufactured by Daikin Industries, Ltd. (Fluororubber 5
Uncolored fluororubber latex consisting of 0% by mass) ... 60% by mass
・ Curing agent ("Daiel Latex GL-200" manufactured by Daikin Industries, Ltd.)
... 5% by mass (outer)
To obtain a surface layer material containing 4 parts by mass of fluoro rubber with respect to 1 part by mass of the fluororesin. The obtained surface layer material was coated on the elastic layer obtained above with an electrostatic coating gun. After drying, it was cured in an oven at 150 ° C. for 60 minutes to form a surface layer having a thickness of 16.6 μm, and a transfer belt was produced. The IRHD hardness was 78.

Further, the hardness measured at the time of 10 mgf loading with a nanoindenter from the transfer belt surface layer side on the iron plate was 0.78 MPa, and the micro hardness (IRHD) was 62.

Further, the surface resistivity on the surface layer side of the transfer belt was 10.0, the surface resistivity on the base layer side was 10.0, and the volume resistivity was 8.5.

(Example 5)
・ “Daiel Latex GLS-213CR” manufactured by Daikin Industries, Ltd. (uncolored fluororubber latex consisting of 25% by mass of fluororubber and 25% by mass of fluororesin)
... 80% by mass
・ “Daiel Latex GL-252CR” manufactured by Daikin Industries, Ltd. (Fluororubber 5
Uncolored fluororubber latex consisting of 0% by mass) ... 20% by mass
・ Curing agent ("Daiel Latex GL-200" manufactured by Daikin Industries, Ltd.)
... 5% by mass (outer)
To obtain a surface layer material containing 1.5 parts by mass of fluoro rubber with respect to 1 part by mass of the fluororesin. The obtained surface layer material was coated on the elastic layer obtained above with an electrostatic coating gun. After drying, it was cured in an oven at 150 ° C. for 60 minutes to form a surface layer having a thickness of 14.2 μm, and a transfer belt was produced. The film thickness was measured using a dial gauge. The IRHD hardness was 94.

Further, the hardness measured at the time of 10 mgf loading with a nanoindenter from the surface side of the transfer belt on the iron plate was 1.75 MPa, and the micro hardness (IRHD) was 65.

Further, the surface resistivity on the surface layer side of the transfer belt was 10.0, the surface resistivity on the base layer side was 10.0, and the volume resistivity was 8.5.

(Example 6)
The obtained surface layer material obtained in Example 5 was coated on the elastic layer in the same manner as in Example 7 using an electrostatic coating gun. After drying, the film was cured in an oven at 150 ° C. for 60 minutes, and when a film thickness was measured using a dial gauge in the same manner as in Example 1, a surface layer of 6.4 μm was formed to produce a transfer belt. The IRHD hardness was 94.

Further, the hardness measured at the time of 10 mgf loading with a nanoindenter from the surface side of the transfer belt on the iron plate was 0.56 MPa, and the micro hardness (IRHD) was 63.

Further, the surface resistivity on the surface layer side of the transfer belt was 10.0, the surface resistivity on the base layer side was 10.0, and the volume resistivity was 8.5.

(Example 7)
(Formation of elastic layer)
On the same base layer as in Example 1, the components contained in the curing agent shown in Table 1 above are first mixed in the proportions shown in Table 1, and the resulting curing agent and the main agent are mixed in the proportions shown in Table 1. Then, an elastic layer material was prepared and applied in the same manner using the same apparatus as that used for the base layer preparation to form an elastic layer. Next, the belt coated with the elastic layer material on the base layer was heated at 150 ° C. for 1 hour to cure the elastic layer. The elastic layer had a thickness of 200 μm and a JIS A hardness of 30.
(Formation of surface layer)
Water-based urethane paint with urethane resin as binder, fluororesin powder (PTFE)
) 1% by weight or less and a silicone resin (urethane paint “TW805” manufactured by Japan Atchison Co., Ltd.) each containing 5% by mass to 20% by mass, and a curing agent (“WHI” manufactured by Japan Atchison Co., Ltd.). ]) Was mixed at a ratio of main agent: curing agent = 95: 5 (mass ratio) to obtain a surface layer material. The obtained surface material was coated on the elastic layer with an electrostatic coating gun. 120 after drying
It was cured in an oven at 0 ° C. for 10 minutes to form a surface layer having a film thickness of 10.3 μm to obtain a transfer belt. The film thickness was measured using a dial gauge. The IRHD hardness was 62.

Moreover, the hardness measured at the time of 10 mgf load by a nano indenter from the surface side of the transfer belt on the iron plate was 0.48 MPa, and the micro hardness (IRHD) was 60.

Further, the surface resistivity on the surface layer side of the transfer belt was 10.0, the surface resistivity on the base layer side was 10.0, and the volume resistivity was 8.5.

In the image forming apparatus shown in FIG. 2, the belt driving roller 41 has a steel diameter of 65.
It was a roller of mm, and the surface was subjected to urethane coating treatment of several μm.

The secondary transfer roller 61 has a structure in which a sheet is wound around a steel roller surface and supported by a recess. The sheet is a polyimide amide film having a film thickness of 100 μm as a base layer and a tensile elastic modulus of 3000 MPa, and an elastic layer. A conductive urethane rubber layer (JISA hardness 50 °) having a thickness of 2000 μm was provided as a surface layer, and a water-based fluororubber paint (“GLS-213F” manufactured by Daikin Industries, Ltd.) having a thickness of 15 μm was provided on the elastic layer. The hardness measured at the time of 10 mgf load by the nanoindenter from the surface layer side is 4.5 MPa.
The micro hardness (IRHD) was 55. The surface resistivity on the surface layer side is 8.0.
And the volume resistivity was 7.0.

The obtained secondary transfer roller 61 was brought into contact with the belt driving roller via the transfer belt 40. The load at the time of contact can be 10 to 100 kgf, but in the image forming apparatus of FIG.
kgf and a desired nip width of 5 mm.

The results of the physical properties of the transfer belt and the secondary transfer roller of each example and the amount of toner attached to the secondary transfer roller 61 obtained when the image forming apparatus of FIG. 1 is driven under the above conditions are shown below. Shown in the table below.

(Application to the image forming apparatus shown in FIG. 3)
The transfer belt of Example 6 used in the image forming apparatus shown in FIG. 2 was applied to the image forming apparatus provided with the double-sided printing mechanism shown in FIG. 3, and 10000 double-sided printing was performed. At the time of printing, image quality defects such as offset were not recognized.

10Y, 10M, 10C, 10K ... photoconductor, 11Y, 11M, 11C, 11K ... corona charger, 12Y, 12M, 12C, 12K ... exposure unit, 13Y, 13M, 13C, 1
3K: first photosensitive member squeeze roller, 13Y ', 13M', 13C ', 13K' ... second
Photosensitive squeeze roller, 14Y, 14Y ′, 14M, 14M ′, 14C, 14C ′,
14K, 14K '... photosensitive squeeze roller cleaning blade, 16Y, 16M,
16C, 16K ... Photoconductor cleaning roller, 18Y, 18M, 18C, 18K ... Photoconductor cleaning blade, 20Y, 20M, 20C, 20K ... Developing roller, 21Y, 2
1M, 21C, 21K ... developing roller cleaning blade, 22Y, 22M, 22C,
22K ... compaction corona generator, 30Y, 30M, 30C, 30K ... developing device, 3
1Y, 31M, 31C, 31K ... developer container, 32Y, 32M, 32C, 32K ... anilox roller, 31Y, 31M, 31C, 31K ... developer container, 33Y, 33M, 33
C, 33K ... regulating blade, 34Y, 34M, 34C, 34K ... auger (supply roller)
, 40 ... transfer belt, 41 ... belt drive roller, 42 ... tension roller, 45 ... developer recovery section, 46 ... transfer belt cleaning roller, 47 ... transfer belt cleaning roller cleaning blade, 49 ... transfer belt cleaning blade, 50Y, 50M
50C, 50K ... primary transfer part, 51Y, 51M, 51C, 51K ... primary transfer backup roller, 60 ... secondary transfer unit, 61 ... secondary transfer roller, 62 ... secondary transfer roller cleaning blade, 74 ... ( Cleaning) Blade gripping member, 85... Secondary transfer unit collection and storage unit, 90... Fixing unit, 91... Heating roller, 92.
5 ... 1st transfer roller, 96 ... 2nd transfer roller, 101, 101 '... Gate roller,
DESCRIPTION OF SYMBOLS 102 ... Transfer material conveyance guide, 210 ... 1st guide member, 211 ... Case part, 212 ... Suction surface, 215 ... Airflow generation part, 230 ... Transfer material conveyance apparatus, 231 ... Case part, 232 ... Suction surface,
233 ... Branch member, 235 ... Airflow generator, 250 ... Transfer material transport member, 251 ... Transfer material transport member drive roller, 252,253 ... Transfer material transport member stretching roller, 270 ... Second guide member, 271 ... Housing Body part, 272 ... suction surface, 275 ... airflow generation part, 400 ... air blower, 4
DESCRIPTION OF SYMBOLS 01 ... Housing | casing part, 402 ... Opening part, 405 ... Airflow generation part, 523 ... Base layer, 525 ... Elastic layer, 527 ... Surface layer, 529 ... Outer peripheral surface, 530 ... Inner peripheral surface, a ... Transducer, b ... Ber
kovich indenter

Claims (5)

A transfer belt having at least three layers of a base layer, an elastic layer and a surface layer, and carrying an image developed with a liquid developer;
A roller around which the transfer belt is wound;
Having an elastic layer, the hardness when measured at a load of 10 mgf from the peripheral surface side with a nanoindenter is the first hardness, and the IRHD hardness measured from the peripheral surface side is the second hardness, A transfer roller in contact with the roller via a transfer belt,
In a state where the transfer belt is wound around the roller, the hardness measured at the time of 10 mgf load from the surface layer side of the transfer belt by the nanoindenter is a third hardness, and the transfer belt is applied to the roller. When the IRHD hardness measured from the surface layer side of the transfer belt is the fourth hardness in the wound state,
A transfer device characterized by having a relationship of third hardness <first hardness fourth hardness> second hardness. The transfer roller has a cleaning member that contacts the peripheral surface of the transfer roller.
The transfer apparatus described. The transfer roller has a recess formed in the axial direction of the peripheral surface of the transfer roller, and an elastic sheet support member disposed in the recess, and the elastic layer is supported by the elastic sheet supported by the elastic sheet support member. The transfer device according to claim 1, which is configured. A latent image carrier on which a latent image is formed;
A developing section for developing the latent image with a liquid developer;
A transfer belt having at least three layers of a base layer, an elastic layer and a surface layer, onto which an image developed by the developing unit is transferred;
A roller around which the transfer belt is wound;
Having an elastic layer, the hardness when measured at a load of 10 mgf from the peripheral surface side with a nanoindenter is the first hardness, and the IRHD hardness measured from the peripheral surface side is the second hardness, A transfer roller in contact with the roller via a transfer belt,
In a state where the transfer belt is wound around the roller, the hardness measured at the time of 10 mgf load from the surface layer side of the transfer belt by the nanoindenter is a third hardness, and the transfer belt is applied to the roller. When the IRHD hardness measured from the surface layer side of the transfer belt is the fourth hardness in the wound state,
An image forming apparatus having a relationship of third hardness <first hardness fourth hardness> second hardness. A transfer unit that conveys the transfer material to a transfer nip formed by contact between the transfer belt and the transfer roller, and transfers the image to the first surface of the transfer material; and the first surface of the transfer material. A fixing unit for fixing the transferred image;
The transfer material on which the image is fixed by the fixing unit is conveyed, and the second surface, which is the surface opposite to the first surface of the transfer material, is conveyed so as to contact the transfer belt constituting the transfer unit. A transport section to perform,
The image forming apparatus according to claim 4, further comprising:

Images