JP2016126127A - Transfer conveyance device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer conveyance device that can achieve both stable conveyance of sheets and sufficient removal of a toner attached to an endless belt.SOLUTION: A transfer conveyance device of the present invention comprises an endless belt for conveying a transfer material, and a cleaning part that includes a rubber blade for removing a toner attached to a surface of the endless belt. The rubber blade includes a surface that can slide on the surface of the endless belt, and has a potential of 13 V or more and 62 V or less after two seconds from application of a corona discharge of 4 kV to the surface of the endless belt. The rubber blade has a rebound resilience value at 10°C of 18% or more and 39% or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a transfer conveyance device and an image forming apparatus.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a transfer conveyance device used for an image forming apparatus or the like. The transfer conveyance device described in Patent Document 1 uses an endless belt stretched between a driving roller and a driven roller to convey a sheet and transfer a toner image on a photosensitive drum to the sheet. ing. The transfer conveyance device described in Patent Document 1 includes a blade that slides on an endless belt for cleaning. Patent Document 1 describes that by providing the blade slightly downstream where the endless belt is separated from the driving roller, a sufficient cleaning effect can be obtained without impairing the transportability of the belt itself. Yes.

Japanese Patent No. 2838550

  In general, an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine includes a photosensitive drum, a charging device, an exposure device, a developing device, a transfer device, a cleaning device, a fixing device, and the like. The toner image formed on the surface of the photosensitive drum is transferred onto a sheet by a transfer device. The transferred toner image is fixed on a sheet by a fixing device.

  In the image forming apparatus as described above, in order to stably convey the paper and increase the printing speed, a transfer conveyance device using an endless belt made of rubber is adopted as the transfer device. It has increased in recent years. In such a transfer / conveying device, an endless belt is stretched between a driving roller and a driven roller and rotates. By electrostatically attracting the sheet to the endless belt, the sheet is conveyed between the photosensitive drum and the transfer roller, and the toner image on the photosensitive drum is electrically transferred to the sheet by the transfer roller. . Thereafter, the endless belt conveys the paper to a fixing device provided downstream.

  Further, a part of the toner constituting the toner image may adhere to the endless belt. Such toner causes the back side of the paper to become dirty. For this reason, a method of providing a blade that slides on an endless belt for cleaning, as in the transfer conveyance device described in Patent Document 1, is known. By sufficiently removing the toner adhering to the endless belt by this blade, the stain on the back surface of the paper is suppressed.

  However, for the following reasons, it is possible to achieve both the stable conveyance of paper by the endless belt and the sufficient removal of the toner adhering to the endless belt by the blade that slides on the endless belt. It can be difficult.

  That is, when the adsorbing force of the paper on the endless belt is large, the conveyance of the paper is stable, whereas the electromirror force on the toner of the endless belt is large, so the adhesion force of the toner to the endless belt is also high. To increase. Therefore, it becomes difficult to sufficiently remove the toner adhering to the endless belt. In addition, when the adsorbing force of the paper on the endless belt is small, it is easy to remove the toner adhering to the endless belt, whereas the paper is easily separated from the endless belt, so that the paper is conveyed. Becomes unstable.

  Then, the adsorbing force of the paper to the endless belt and the adhesion force of the toner to the endless belt change by continuing to use the endless belt (hereinafter sometimes referred to as “endurance change”). It depends on the external environment. Specifically, as durability changes, the adsorbing force of the paper on the endless belt and the adhesion force of the toner to the endless belt increase. In addition, the adsorbing power of the paper to the endless belt and the adhesion force of the toner to the endless belt decrease in a high temperature and high humidity environment, whereas the endless belt has a low adhesion in the low temperature and low humidity environment. The adsorption force to the paper and the adhesion force of the toner to the endless belt increase.

  Therefore, at a certain point in time, the paper is stably conveyed by the endless belt and the toner adhering to the endless belt is sufficiently removed by the blade that slides on the endless belt. However, the durability changes and the usage environment changes, so that the paper is stably conveyed and the toner attached to the endless belt is sufficiently removed by the blade that slides on the endless belt. One of them will not be fully achieved. For example, as the durability changes, the paper adsorption force to the endless belt increases, so that the toner adsorption force to the endless belt becomes too large, particularly in an environment of low temperature and low humidity. It may be difficult to sufficiently remove the toner. In order to prevent such a problem, if the endless belt is formed so that the adsorption force of the paper to the endless belt in the initial stage of use becomes small, it is possible to remove the toner from the endless belt even if the durability changes. Since the adsorbing force of the endless belt on the sheet in the initial stage of use is small, the sheet is likely to be separated from the endless belt particularly in a high-temperature and high-humidity environment, and the conveyance of the sheet becomes unstable.

  Based on the above reasons, it may be difficult for the conventional transfer conveyance device to achieve both the stable conveyance of the paper by the endless belt and the sufficient removal of the toner adhering to the endless belt. there were.

  The present invention has been made in view of such a problem, and it is easy to achieve both stable conveyance of a sheet by an endless belt and sufficient removal of toner attached to the endless belt. It is an object of the present invention to provide a transfer conveyance device and an image forming apparatus including such a transfer conveyance device.

  In order to solve the above-described problems, a transfer conveying device according to the present invention includes a plurality of rollers, an endless belt for conveying a transfer material that is spanned between the plurality of rollers and rotated by the plurality of rollers. An electric field applying means provided on the back side of the endless belt, the toner image so that the toner image on the image carrier provided on the front side of the endless belt is electrically transferred to a transfer material. A transfer portion having an electric field applying means for applying a transfer electric field to the surface, and a cleaning portion having a rubber blade for removing the toner adhering to the surface of the endless belt. The endless belt has a rubber base portion. The rubber blade has a rubber base portion, and the surface of the rubber blade is slidable on the surface of the endless belt at the tip of the rubber blade, and a corona discharge of 4 kV is applied to the surface of the endless belt. Potential applied to 2 seconds after the surface is more than 13V, or less 62V, impact resilience values at 10 ° C. of the rubber blade 18% or more and equal to or less than 39%.

  In the transfer conveyance device according to the present invention, the rebound resilience value at 10 ° C. of the rubber blade is 18% or more, so that the ability to remove the toner adhering to the endless belt by the rubber blade can be obtained even in a low temperature and low humidity environment. Can be maintained. Moreover, when the said impact resilience value exceeds 39%, the rubber sag of a rubber blade will deteriorate. Therefore, by setting the impact resilience value to 18% or more and 39% or less, even if the toner adheres firmly to the endless belt due to the low temperature and low humidity environment, the toner can be easily removed by the rubber blade. . Furthermore, since the surface potential (residual power) after 2 seconds after applying a 4 kV corona discharge to the surface of the endless belt is limited to a range of 13 V or more and 62 V or less, It is possible to suppress the endurance change in the residual power characteristics (surface charging characteristics after voltage application). Further, since the residual power is 13 V or more, the adsorption force of the paper to the endless belt can be sufficiently increased. For these reasons, according to the transfer conveyance device of the present invention, it is possible to sufficiently increase the adsorption force of the sheet to the endless belt and to suppress the durability change of the adhesion force of the toner to the endless belt. Therefore, it is possible to achieve both the stable conveyance of the sheet by the endless belt and the sufficient removal of the toner adhering to the endless belt.

  Furthermore, the transfer / conveying apparatus according to the present invention preferably further includes a coating layer provided on the rubber base portion of the endless belt and defining the surface of the endless belt. This facilitates adjustment of the characteristic value of the surface of the endless belt that affects the adsorbing force of the paper to the endless belt and the adhesion force of the toner to the endless belt. Therefore, it is easier to achieve both the stable conveyance of the sheet by the endless belt and the sufficient removal of the toner adhering to the endless belt.

  Furthermore, in the transfer conveying apparatus according to the present invention, it is preferable that the rubber blade further has a coating layer provided on the rubber base portion of the rubber blade and defining the surface of the rubber blade. This facilitates adjustment of the characteristic value of the surface of the rubber blade that affects the ability of the rubber blade to remove the toner attached to the endless belt. Therefore, it is easier to achieve both the stable conveyance of the sheet by the endless belt and the sufficient removal of the toner adhering to the endless belt.

  Furthermore, in the transfer conveyance device according to the present invention, the coating layer of the endless belt preferably contains carbon black having an average primary particle diameter of 22 nm or more and 66 nm or less. The inventors have found that, by setting the average primary particle diameter within this range, it is possible to easily suppress the endurance change of the residual power characteristics (surface charging characteristics after voltage application) of the endless belt. Specifically, by setting the average primary particle size to 22 nm or more and 66 nm or less, 2 seconds after applying a 4 kV corona discharge to the surface of the endless belt even if the endless belt is used continuously. The inventors have found that the surface potential (residual power) can be easily suppressed to a range of 13 V or more and 62 V or less. Therefore, it is easier to achieve both the stable conveyance of the sheet by the endless belt and the sufficient removal of the toner adhering to the endless belt.

  Furthermore, in the transfer conveyance device according to the present invention, the static friction coefficient of the surface of the endless belt can be set to 0.4 or more and 0.8 or less. From the viewpoint of making it difficult for toner to adhere to the surface of the endless belt, the coefficient of static friction on the surface of the endless belt is preferably as small as possible. Therefore, in the transfer / conveying apparatus according to the present invention, it is preferable to reduce the static friction coefficient by a method such as forming a coating layer that reduces chemical adhesion on the surface of the rubber substrate. Since the size of the coefficient of static friction may be uneven depending on the location on the surface of the endless belt, the maximum value of the coefficient of static friction realized in a location where the coating layer is thin may be 0.8. The minimum value of the static friction coefficient realized in a place where the coating layer is thick can be set to 0.4.

  Furthermore, in the transfer conveying apparatus according to the present invention, the ten-point average roughness of the surface of the endless belt can be 1.6 μm or more and 10.2 μm or less. From the viewpoint of suppressing the toner adhering to the surface of the endless belt from physically passing through the rubber blade, the ten-point average roughness is preferably as small as possible. Since the manufacturing conditions of the endless belt such as the polishing conditions for the rubber base portion in the polishing process may be uneven, the maximum value of the ten-point average roughness corresponding to the location where the surface irregularities are large is 10.2 μm. And the minimum value of the ten-point average roughness corresponding to a small surface irregularity can be 1.6 μm.

  Furthermore, in the transfer conveyance device according to the present invention, the dynamic friction coefficient at the tip of the rubber blade at a temperature of 30 ° C. and a humidity of 85% is preferably as small as possible, and is preferably 5.3 or less. Since the dynamic friction coefficient is 5.3 or less, the rubber blade that slides on the surface of the endless belt can be prevented from flipping even in a high temperature and high humidity environment. The toner adhering to the belt can be stably removed. As a result, it is easier to achieve both the stable conveyance of the paper by the endless belt and the sufficient removal of the toner adhering to the endless belt. Further, the lower limit value as a manufacturing limit of the dynamic friction coefficient of the tip portion of the rubber blade is 2.6.

  Furthermore, in the transfer conveyance device according to the present invention, the sphericity of the toner constituting the toner image can be 0.94 or more. When toner having a high sphericity of 0.94 or more adheres to the surface of the endless belt, the toner easily physically slips through the rubber blade that slides on the surface of the endless belt. Therefore, the toner is difficult to be removed by the rubber blade. This makes it particularly difficult for the conventional transfer conveyance device to achieve both the stable conveyance of the paper by the endless belt and the sufficient removal of the toner adhering to the endless belt. Therefore, the effect of the present invention that it is easy to achieve both the stable conveyance of the sheet by the endless belt and the sufficient removal of the toner adhering to the endless belt is exhibited particularly effectively.

  An image forming apparatus according to the present invention includes any one of the above-described transfer conveyance devices.

  According to the present invention, it is easy to achieve both the stable conveyance of a sheet by an endless belt and the sufficient removal of toner adhering to the endless belt, and such a transfer. An image forming apparatus including a transport device is provided.

1 is a schematic diagram illustrating a configuration of an image forming apparatus including a transfer conveyance device according to an embodiment. It is a schematic diagram which shows the structure of the transfer conveyance apparatus which concerns on embodiment. It is a figure which shows typically the structure of the cross section of a transfer belt. It is a figure which shows the measuring method of the residual power of a transfer belt. It is a figure which shows the measuring method of the dynamic friction coefficient (micro | micron | mu) of the front-end | tip of a rubber blade.

  Hereinafter, a transfer conveyance device and an image forming apparatus according to embodiments will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used for the same elements when possible. In addition, the dimensional ratios in the components in the drawings and between the components are arbitrary for easy viewing of the drawings.

  FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus including a transfer conveyance device according to the present embodiment. As shown in FIG. 1, the image forming apparatus 1 includes a recording medium transport unit 10, a transfer transport device 20 having a photosensitive drum 30 as an image carrier, a developing unit (developing device) 40, a fixing unit 50, and a toner. A tank 60 is mainly provided.

  The recording medium conveyance unit 10 accommodates a sheet P as a recording medium (transfer material) on which an image is finally formed, and conveys the sheet P onto the recording medium conveyance path R. The sheets P are stacked and stored in a cassette. The recording medium conveyance unit 10 causes the paper P to reach the transfer conveyance device 20 via the recording medium conveyance path R.

  The transfer conveyance device 20 conveys the paper P to the transfer area via the recording medium conveyance path R at a timing at which the toner image formed by the developing unit 40 is transferred to the paper P. The transfer conveyance device 20 includes a transfer belt 24, stretching rollers 22 and 23 that stretch the transfer belt 24, and a transfer roller 21 that serves as an electric field applying unit facing the photosensitive drum 30. The transfer belt 24 is an endless belt that is stretched between the stretching rollers 22 and 23. One of the two stretching rollers receives driving from the main body and applies driving to the transfer belt 24 as a driving roller. As a result, the transfer belt 24 rotates. The transfer belt 24 conveys the paper P as the transfer belt 24 rotates by attracting the paper P to the surface of the transfer belt 24. The transfer roller 21 is provided on the back side of the transfer belt 24. In this embodiment, the transfer roller 21 is in contact with the back surface of the transfer belt 24 and rotates as the back surface of the transfer belt 24 moves. The transfer conveyance device 20 includes a cleaning unit 25 that removes toner adhering to the surface of the transfer belt 24.

  The photoconductor drum 30 is an electrostatic latent image carrier on which an image is formed on the peripheral surface, and is made of, for example, OPC (Organic PhotoConductor). The photosensitive drum 30 is provided on the surface side of the transfer belt 24. The image forming apparatus 1 according to the present embodiment further includes a charging roller 31, an exposure unit 35, a developing unit 40, and a cleaning member 32, as shown in FIG.

  The charging roller 31 uniformly charges the surface of the photosensitive drum 30 to a predetermined potential. The exposure unit 35 exposes the surface of the photosensitive drum 30 charged by the charging roller 31 according to an image formed on the paper P. As a result, the potential of the portion of the surface of the photosensitive drum 30 exposed by the exposure unit changes, and an electrostatic latent image is formed. The developing unit 40 includes a developing roller 41, a supply auger 42, and an admix auger 43, and an electrostatic latent image formed on the surface of the photosensitive drum 30 with toner supplied from the toner tank 60 using these. To develop a toner image. The transfer roller 21 is configured to apply an electric field (transfer electric field) to the toner image so that the toner image on the surface of the photosensitive drum 30 is electrically transferred to the paper P. Therefore, the toner image is electrically transferred to the paper P conveyed to the transfer area by the transfer roller 21. The transfer unit of the transfer conveyance device 20 according to the present embodiment includes a transfer roller 21 and a photosensitive drum 30. As described above, the electric field applying unit of the present embodiment is the transfer roller 21 based on the roller transfer method, but a corona discharger based on the corona transfer method can also be used as the electric field applying unit. The toner tank 60 is filled with toner. A neutralizing lamp that resets the potential of the photosensitive drum 30 may be disposed on the circumference of the photosensitive drum 30 immediately upstream of the charging roller 31 in the rotation direction of the photosensitive drum 30.

The toner tank 60 can store spherical toner. Here, the particle diameter of the spherical toner may be 5 μm, and the sphericity may be 0.94 or more. For the sphericity of the toner, the sphericity of the particles measured using a flow particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation) was obtained from the following equation, and the total sphericity of all particles measured was measured. The value divided by the total number of particles.
Sphericality = (perimeter of a circle with the same projected area as the particle image) / (perimeter of the projected image of the particle)
The sphericity in the present embodiment is an index of the degree of unevenness of toner particles, and is 1.000 when the toner is a perfect sphere, and the circularity becomes smaller as the toner shape becomes more complicated.

  Spherical toner can give a higher quality image than non-standard toner, and by using a toner having a sphericity of 0.94 or more, a particularly high quality image can be formed. However, the spherical toner tends to physically pass through the cleaning unit 25, and the toner that has passed through the cleaning unit 25 tends to adversely affect the image.

  The fixing unit 50 fixes the toner image transferred to the paper P only by electrostatic force on the paper P at a high temperature. The fixing unit 50 includes, for example, a heating roller 52 and a pressure roller 51. The heating roller 52 is a cylindrical member that can rotate around a rotation axis, and a heat source such as a halogen lamp is provided therein. The pressure roller 51 is a cylindrical member that can rotate around the rotation axis, and is provided to press the heating roller 52. On the outer peripheral surfaces of the heating roller 52 and the pressure roller 51, for example, a heat-resistant elastic layer such as silicone rubber is provided. By passing the paper through a fixing nip, which is a contact area between the heating roller 52 and the pressure roller 51, the toner image is melted and fixed on the paper. Then, the paper P on which the toner image is fixed is discharged to the outside of the image forming apparatus 1.

  Next, a more detailed configuration of the transfer conveyance device will be described. FIG. 2 is a schematic diagram illustrating a configuration of the transfer conveyance device according to the present embodiment. As shown in FIG. 2, the transfer belt 24 has a rubber base portion 24A and a coating layer 24B formed on the rubber base portion 24A. The coating layer 24B has a thickness of 5 μm, for example. The coating layer 24B is provided in order to reduce the chemical adhesive force on the surface of the transfer belt 24 and reduce the static friction coefficient of the surface. The rubber base portion 24A is an elastic portion made of rubber. The coating layer 24 </ b> B defines the surface of the transfer belt 24. The cleaning unit 25 includes a plate-like rubber blade 27 and a holder 29 made of metal or the like that fixes the rubber blade 27. The rubber blade 27 includes a rubber base portion 27A and a coating layer 27B formed on the rubber base portion 27A. The rubber base portion 27A is a plate-like elastic portion made of rubber and has a thickness of 2 mm, for example. The coating layer 27B defines the surface of the rubber blade 27 and has a thickness of, for example, 5 μm. The base end portion of the rubber blade 27 is fixed to the holder 29 with a predetermined length, and the portion corresponding to the free length F27 is not fixed to the holder 29. The surface of the rubber blade 27 is slidable in contact with the surface of the transfer belt 24 rotating along the arrow D at a predetermined acute angle θ at the tip. Thereby, the toner adhering to the surface of the transfer belt 24 can be removed by the rubber blade 27 of the cleaning unit 25.

  FIG. 3 is a diagram schematically showing a cross-sectional configuration of the transfer belt. As shown in FIG. 3, the surface of the rubber base portion 24 </ b> A of the transfer belt 24 has unevenness, and the surface of the coating layer 24 </ b> B also has unevenness along with the unevenness. The thickness of the rubber base portion 24A is, for example, 600 μm, and the thickness T24A of the coating film layer 24B is, for example, 5 μm. The coating layer 24B contains carbon black having an average primary particle size of 22 nm or more and 66 nm or less. Here, the average primary particle diameter of carbon black is a value measured by an electron microscope.

  In the transfer conveyance device 20 of the present embodiment as described above, the rebound resilience value at 10 ° C. of the rubber blade 27 is 18% or more, so that the transfer belt 24 by the rubber blade 27 is applied to the transfer belt 24 even in a low temperature and low humidity environment. The ability to remove adhering toner can be maintained. Moreover, when the said impact resilience value exceeds 39%, the rubber sag of the rubber blade 27 will deteriorate. Therefore, by setting the impact resilience value to 18% or more and 39% or less, even if the toner adheres firmly to the transfer belt 24 due to the low temperature and low humidity environment, the rubber blade 27 can easily remove the toner. Become.

  The rebound resilience value of the rubber blade 27 described above is a value obtained by a Lübke rebound resilience test apparatus in accordance with JISK6255.

  Furthermore, in the transfer conveyance device 20 according to the present embodiment, the surface potential (residual power) after 2 seconds from the application of the 4 kV corona discharge to the surface of the transfer belt 24 is 13 V or more and 62 V or less. . Since the residual power is limited to such a range, it is possible to suppress the endurance change of the residual power characteristics (surface charging characteristics after voltage application) of the endless belt. Further, since the residual power is 13 V or more, the adsorption force of the paper to the endless belt can be sufficiently increased. For these reasons, according to the transfer conveyance device 20 according to the present embodiment, the adsorption force of the paper P to the transfer belt 24 is sufficiently increased, and the durability change of the adhesion force of the toner to the transfer belt 24 is suppressed. Therefore, it is possible to achieve both the stable conveyance of the paper P by the transfer belt 24 and the sufficient removal of the toner adhering to the transfer belt 24.

  The surface potential (residual power) 2 seconds after the application of 4 kV corona discharge to the surface of the transfer belt 24 is a value measured as follows. That is, the surface potential at an arbitrary position on the surface of the transfer belt 24 can be measured by scanning a carriage incorporating a corona charger and an electrostatic probe along the surface of the transfer belt 24. And, “the potential of the surface (residual power) after 2 seconds from the application of 4 kV corona discharge to the surface of the transfer belt 24” means that the charging device applies a voltage of 4 kV to the corona charger. This is the electric potential of the surface of the transfer belt 24 measured by a probe that is charged and 2 seconds after the charge is positioned backward with respect to the traveling direction of the charger. The distance between the surface of the transfer belt 24 to be measured and the probe is 1.00 mm, and the scanning speed of the carriage is 400 mm / second.

  Further, the transfer conveyance device 20 according to the present embodiment further includes a coating layer 24B provided on the rubber base portion 24A of the transfer belt 24 and defining the surface of the transfer belt 24. As a result, the characteristic value of the surface of the transfer belt 24 that affects the adsorbing force of the paper to the transfer belt 24 and the adhesion force of the toner to the endless belt (for example, the residual electric power of the transfer belt 24 and the surface of the transfer belt 24). The following static friction coefficient, etc.) can be easily adjusted. For this reason, it becomes easier to stably transport the paper P by the transfer belt 24 and sufficiently remove the toner attached to the transfer belt 24. However, the transfer belt 24 may not have the coating layer 24B.

  Furthermore, in the transfer conveyance device 20 according to the present embodiment, the rubber blade 27 further includes a coating layer 27B provided on the rubber base portion 27A of the rubber blade 27 and defining the surface of the rubber blade 27. . This facilitates adjustment of the characteristic value (for example, the following dynamic friction coefficient of the rubber blade 27) of the rubber blade 27 that affects the ability of the rubber blade 27 to remove the toner attached to the transfer belt 24. Therefore, it is easier to stably transport the paper P by the transfer belt 24 and sufficiently remove the toner attached to the transfer belt 24. However, the rubber blade 27 may not have the coating layer 27B.

  Furthermore, in the transfer conveyance device 20 according to this embodiment, the coating layer 24B of the transfer belt 24 includes carbon black having an average primary particle diameter of 22 nm or more and 66 nm or less. The inventors have found that by making the average primary particle diameter within this range, it is possible to easily suppress the endurance change in the residual power characteristics (surface charging characteristics after voltage application) of the transfer belt 24. Specifically, by setting the average primary particle size to 22 nm or more and 66 nm or less, 2 seconds after applying a 4 kV corona discharge to the surface of the transfer belt 24 even if the transfer belt 24 is continuously used. The inventors have found that the surface potential (residual power) can be easily suppressed to a range of 13 V or more and 62 V or less. For this reason, it becomes easier to stably transport the paper P by the transfer belt 24 and sufficiently remove the toner attached to the transfer belt 24. However, the coating film layer 24 </ b> B of the transfer belt 24 may not contain carbon black as described above.

  Furthermore, in the transfer conveying device 20 according to the present embodiment, the static friction coefficient of the surface of the transfer belt 24 can be set to 0.4 or more and 0.8 or less. From the viewpoint of making it difficult for toner to adhere to the surface of the transfer belt 24, the coefficient of static friction on the surface of the transfer belt 24 is preferably as small as possible. Therefore, in the transfer conveyance device 20 according to the present embodiment, the static friction coefficient can be reduced by a method such as forming a coating layer 24B that reduces chemical adhesion on the surface of the rubber base portion 24A. preferable. Since the magnitude of the static friction coefficient may be non-uniform depending on the place on the surface of the transfer belt 24, the maximum value of the static friction coefficient realized in a place where the coating film layer 24B is thin is set to 0.8. The minimum value of the static friction coefficient realized in a place where the coating layer 24B is thick can be set to 0.4.

  Furthermore, in the transfer conveyance device 20 according to the present embodiment, the ten-point average roughness of the surface of the transfer belt 24 can be 1.6 μm or more and 10.2 μm or less. From the viewpoint of suppressing the toner adhering to the surface of the transfer belt 24 from physically passing through the rubber blade 27, the ten-point average roughness is preferably as small as possible. There may be non-uniformity in the manufacturing conditions of the transfer belt 24 such as the polishing conditions for the rubber base portion 24A in the polishing process. Therefore, the maximum value of the ten-point average roughness corresponding to a place where the surface unevenness is large can be 10.2 μm, and the minimum value of the ten-point average roughness corresponding to a place where the surface unevenness is small is 1 .6 μm.

  The static friction coefficient of the surface of the transfer belt 24 described above was measured under an environment of 30 ° C. and 85% by a portable friction meter 3D Muse TYPE 37 manufactured by Shinto Kagaku Co., Ltd. using 40 g of brass subjected to hard chrome treatment as a slider. It is a value measured by placing the tribometer gently on the surface of the transfer belt 24 placed on a horizontal plane. Further, the ten-point average roughness of the surface of the transfer belt 24 described above is a value measured using a shape analysis laser microscope VK-X100 manufactured by KEYENCE.

  Further, in the transfer conveyance device 20 according to the present embodiment, it is preferable that the dynamic friction coefficient of the tip portion of the rubber blade 27 at a temperature of 30 ° C. and a humidity of 85% is as small as possible. From this point of view, in the present embodiment, the coating layer 27B that reduces the chemical adhesion is formed on the surface of the rubber base portion 27A. The dynamic friction coefficient may also be nonuniform depending on the location, for example, because the film thickness of the coating layer 27B may be nonuniform depending on the location. Therefore, the maximum value of the coefficient of dynamic friction at the temperature 30 ° C. and the humidity 85% at the tip of the rubber blade 27 realized in a place where the coating layer 27B is thin can be set to 5.3. The minimum value of the dynamic friction coefficient realized in a thick place or the like can be 2.6. It can also be said that the value of the dynamic friction coefficient of 2.6 is a manufacturing limit value of the tip portion of the rubber blade 27. Since the dynamic friction coefficient is 5.3 or less, the rubber blade 27 sliding on the surface of the transfer belt 24 can be prevented from flipping even in a high temperature and high humidity environment. The toner adhering to the transfer belt 24 can be stably removed. As a result, it becomes easier to achieve both the stable conveyance of the sheet by the transfer belt 24 and the sufficient removal of the toner adhering to the transfer belt 24.

  Furthermore, in the transfer conveyance device 20 according to the present embodiment, the sphericity of the toner constituting the toner image can be 0.94 or more. When toner having a sphericity as high as 0.94 or higher is attached to the surface of the transfer belt 24, the toner easily physically slips through the rubber blade 27 sliding on the surface of the transfer belt 24. For this reason, the toner is difficult to be removed by the rubber blade 27. This makes it particularly difficult for the conventional transfer conveyance device to achieve both the stable conveyance of the sheet by the transfer belt and the sufficient removal of the toner adhering to the transfer belt. Therefore, the effect of the transfer conveyance device 20 of the present embodiment that it is easy to achieve both the stable conveyance of the paper P by the transfer belt 24 and the sufficient removal of the toner adhering to the transfer belt 24 is achieved. It is particularly effective.

  Next, a method for manufacturing the transfer belt 24 used in the transfer conveyance device 20 of the present embodiment and an example of a more specific configuration will be described.

  As described above with reference to FIG. 2, the transfer belt 24 includes the rubber base portion 24A, which is an elastic body serving as a base material, and the coating layer 24B on the surface thereof. Examples of the material of the rubber base portion 24A include styrene-butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM), and butyl rubber ( IIR), acrylic rubber (ANM), chlorosulfonated polyethylene rubber (CSM), silicone rubber, fluorine rubber, polysulfide rubber, natural rubber and the like are suitable. Among these rubber materials, one kind can be used alone, or two or more kinds may be used in combination.

When the rubber base portion 24A is configured to be semiconductive (10 ⁴ to 10 ¹² Ω · cm in volume resistivity), a conductive material is added in order to adjust to a predetermined resistance value. Specifically, metal materials such as silver powder, copper powder and nickel powder, metal oxides such as tin oxide and indium oxide, inorganic materials such as mica coated with metal, carbon compounds such as carbon black and graphite, carbon fiber, Illustrative examples include ionic conductive materials such as ammonium thiocyanate. Two or more of these may be used in combination. Among the conductive materials described above, the use of carbon black is particularly preferable because the reinforcing effect of the rubber base portion 24A is also obtained.

  The material of the coating layer 24B is appropriately selected depending on the application. In this embodiment, the material of the coating layer 24B is used to prevent toner adhesion and facilitate removal of the adhered toner by the rubber blade 27. A lubricious paint can be used. As such a lubricating paint, a polyurethane resin binder to which polytetrafluoroethylene fine powder and polyalkylsiloxane are added can be used.

  For the production of the rubber base portion 24A, the above materials are prepared and first kneaded. In the kneading step, the above-mentioned materials, a plasticizer, a stabilizer and a dispersion improver are added and kneaded, and then a vulcanizing agent, a vulcanization accelerator and a crosslink density adjusting agent are added, and they are kneaded in a kneader. An unvulcanized rubber composition is prepared. The crosslinking may be peroxide crosslinking or sulfur vulcanization. The transfer belt 24 is completed by performing an extrusion process, a vulcanization process, a polishing process, and a coating process on the unvulcanized rubber composition.

  In the extrusion process, the unvulcanized rubber composition is coated on the outer surface of the cylindrical mold with a predetermined thickness and supplied to the vulcanization process. In the vulcanization step, the cylindrical mold coated with the unvulcanized rubber composition is set in a vulcanization can, and superheated steam is fed into the vulcanization can and pressurized to vulcanize. In the polishing step, the rubber base material that has been removed from the cylindrical mold is polished with a rotating grindstone while rotating in a stretched state using a mandrel. The thickness of the rubber base material after polishing is not particularly limited, but can be set to, for example, 600 μm in this embodiment. Further, in this step, rubber wear powder is generated and mixed with the paint in the next step, so that convex roughness does not occur. Therefore, it is necessary to clean the rubber base material.

In the painting process, in order to improve the tackiness in the state of the rubber substrate and to obtain lubricity, a mandrel is used to spray a polyurethane resin binder with polytetrafluoroethylene fine powder and polyalkylsiloxane added. By coating, a coating layer 24B having a thickness of 5 ± 2 μm is formed on the surface. By adopting spray coating, the thickness of the coating layer 24B can be easily adjusted.
If necessary, the coating layer 24B may have its electric resistance adjusted to a semiconductive or conductive range. In that case, the coating layer 24B may be made of carbon black or an ionic conductive material. Can be added.

  The transfer belt 24 of the present embodiment was manufactured by the method as described above. When various characteristics of the manufactured transfer belt 24 were measured, the volume resistivity was 9 to 12 Log (Ω · cm), the surface static friction coefficient μs was 0.4 to 0.8, and the surface ten-point average roughness was measured. The thickness Rz was 1.6 to 10.2 μm. The range of the measured values of the various characteristics is due to the fact that the measured value varies to some extent within the single transfer belt 24 that is manufactured, and the measured value varies to some extent depending on the manufacturing lot. The static friction coefficient μs was measured with a portable friction meter 3D muse TYPE 37 manufactured by Shinto Kagaku. The measurement was carried out by placing a friction coefficient measuring device gently on a belt surface placed on a horizontal surface in an environment of 30 ° C. and 85%. The ten-point average roughness Rz is a ten-point average roughness measured using a shape analysis laser microscope VK-X100 (manufactured by KEYENCE). The ten-point average roughness Rz of the surface is an index of the degree of unevenness of the surface of the transfer belt 24, and the larger the value of Rz, the larger the unevenness of the surface. As shown in FIG. 3, the shape of the surface of the coating layer 24B is affected by the unevenness of the surface of the rubber base portion 24A. The spherical toner adhering to the surface of the transfer belt 24 is more easily physically slipped through the rubber blade 27 as the ten-point average roughness Rz of the transfer belt 24 is larger, and the toner slipped through the rubber blade 27 is formed by the image forming apparatus. May adversely affect the displayed image.

  Next, a manufacturing method of the cleaning unit 25 used in the transfer conveyance device 20 of the present embodiment and an example of a more specific configuration will be described.

  As described above with reference to FIG. 2, the transfer conveyance device 20 is configured by attaching a plate-like rubber blade 27 made of polyurethane rubber according to this embodiment to a metal holder 29 that is a rigid plate-like body. ing. The rubber blade 27 includes a rubber base portion 27A and a coating layer 27B. The rubber blade 27 can have a rubber thickness of 2.0 mm, a free length F27 of 8.5 mm, and a width of 334 mm. As for the holder 29, the thickness can be 1.6 mm, and the adhesion width with the rubber blade 27 can be 5 mm. The front surface of the rubber blade 27 is in contact with the surface of the rotating transfer belt 24 so that the rubber blade 27 slides at a contact angle of 19 °. The toner adhering to the surface of the transfer belt 24 is scraped and removed by the tip of the rubber blade 27.

  As a molding method of the rubber base portion 27A of the rubber blade 27, a one-shot method can be used in which a polymer polyol, a polyisocyanate, a crosslinking agent, a catalyst, and the like are mixed at a time and cast into a mold. . Subsequently, in order to control the friction coefficient of the tip portion of the rubber blade 27 at high temperature and high humidity, the coating layer 27B of the rubber blade 27 is applied to the surface treatment solution containing an aromatic polyisocyanate component. Molded by impregnation with 27B.

  Examples of the polyester polyol used for the rubber base portion 27A include ethylene glycol, butanediol, hexanediol, nonanediol, decanediol, 3-methyl-1,5-pentanediol, neopentylglycol, and 2,4-diethyl-1,5. -Combinations of diols such as pentanediol, butylethylpropanediol, 2-methyl-1,8-octanediol and dibasic acids such as adipic acid, azelaic acid, sebacic acid, dimer acid and hydrogenated dimer acid be able to. Specifically, nonanediol adipate, 2-methyl-1,8-octanediol adipate, decanediol adipate, hexanediol azelate, nonanediol azelate, 2-methyl-1,8-octanediol azelate, decanediol Azelate, butanediol sebacate, hexanediol sebacate, nonanediol sebacate, 2-methyl-1,8-octanediol sebacate, decanediol sebacate, dimer acid ester and hydrogenated dimer acid ester of various glycols, etc. is there. Two or more of these can be used in combination.

  However, for the purpose of improving the resilience of the rubber blade 27 in a low temperature and low humidity environment, lactones such as ε-caprolactone and δ-valerolactone are polyadded or copolymerized, or a diol component and a dibasic acid are combined. During the dehydration condensation, a lactone can be copolymerized into a random copolymer, or a polyol obtained by polyaddition of a lactone to the dehydrated condensation can be selected.

  In the molding of the rubber base portion 27A, as the polyisocyanate to be reacted with the polyester polyol, 2,6-toluene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1, 5-Naphthalene diisocyanate (NDI), 3,3-dimethyldiphenyl-4,4′-diisocyanate (TODI) and the like can be mentioned, and two or more of these can be used in combination.

  In order to produce polyurethane using the above-described polyester polyol, polyisocyanate is blended and reacted with the polyester polyol and the short-chain polyol as the chain extender. Here, the short-chain polyol has a number average molecular weight of 500 or less. Specifically, for example, the main chain has a carbon number of ethylene glycol, 1,3-propanediol, 1,4-butanediol or the like. 2-12 linear glycols; diols having a side chain of 12 or less carbon atoms such as neopentyl glycol and 3-methyl-1,5-pentanediol; carbon numbers such as 3-allyloxy-1,2-propanediol Diols having an unsaturated group of 12 or less; and diols having 20 or less carbon atoms containing an aromatic ring such as 1,4-bis (hydroxyethoxy) benzene and paraxylene glycol, cyclohexanediol, and cyclohexanedimethanol Triols such as alicyclic diols such as trimethylol ethane, trimethylol propane and glycerin It can be mentioned tetrafunctional or higher polyols, such as fine pentaerythritol and sorbitol. Two or more of these short-chain polyols can be used in combination.

  In the formation of the coating layer 27B, as the polyisocyanate used in the surface treatment liquid, a polyisocyanate having two or more molecular terminal isocyanate groups in the molecule can be used. Such isocyanates include aromatic and polyisocyanates such as diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate (polymeric MDI), tolylene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), and the like. , Hexamethylene diisocyanate (HDI), aliphatic isocyanates and polyisocyanates of lysine methyl ester diisocyanates, hydrogenated diphenylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), tetramethylxylylene diisocyanate (TMXDI) And alicyclic isocyanates and polyisocyanates such as Two or more of these can be used in combination.

  However, an aromatic polyisocyanate can be selected for the purpose of controlling the coefficient of friction of the tip of the rubber blade 27 at a high temperature and high humidity. Further, the surface treatment liquid can be further reduced in coefficient of friction by using carbon black. By forming the coating film layer 27B in a state where the carbon black is dispersed in the surface treatment liquid, the carbon black can be fixed in the coating film layer 27B. The carbon black in the surface treatment liquid is preferably 20% by weight or less based on the isocyanate component. This is because if the proportion of carbon black is larger than this, problems such as falling off may occur.

  Hereinafter, in order to further clarify the effects of the present invention, description will be made using examples and comparative examples.

Example 1
(Preparation of transfer belt)
The rubber base portion of the transfer belt was produced as follows.

  Chloroprene rubber 75 parts by weight (shown WRT, manufactured by Showa Denko Elastomer Co., Ltd.), EPDM rubber 25 parts by weight (Esprene 505, manufactured by Sumitomo Chemical Co., Ltd.), zinc oxide 5 parts by weight (zinc flower, manufactured by Mitsui Mining & Smelting Co., Ltd.), magnesium oxide 4 Parts by weight (Kyowa Mag 150, manufactured by Kyowa Chemical Industry Co., Ltd.), carbon black 15 parts by weight (Seast 300, manufactured by Tokai Carbon Co., Ltd.), process oil 22 parts by weight (NS-100, manufactured by Idemitsu Kosan Co., Ltd.), and stearic acid 1 part by weight (Lunac S-50V, manufactured by Kao Corporation) was kneaded with a kneader, cooled, and then opened with an open roll, 1 part by weight of sulfur, 0.5 part by weight of ethylenethiourea (Accel 22-S, manufactured by Kawaguchi Chemical Co., Ltd.) and tetramethylthiuram. Add 0.5 parts by weight of disulfide (Noxeller TT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) and knead to make a ribbon. It was fed to the extruder.

  Next, a tubing die is attached to a vent type extruder with a screw diameter of 75 mm, and extrusion molding is performed at a cylinder temperature of 60 ° C., a head temperature of 80 ° C., and a die temperature of 90 ° C. to form a rubber tube having a thickness of 0.6 mm. did. This rubber tube was inserted into a cylindrical mold, steam vulcanized at 190 ° C. for 30 minutes, cooled, polished on the surface, cut into a length of 340 mm, an inner circumference length of 168 mm, and a thickness of 0.6 mm. A rubber base was obtained by polishing.

  A coating layer of the transfer belt was prepared as follows. 100 parts by weight of Teflon (registered trademark) blended resin (Emulalon 345, polytetrafluoroethylene and polyurethane resin and acrylic resin emulsion, manufactured by Henkel Technology Japan), 8 parts by weight of Mitsubishi Carbon # 30 (carbon black, average primary A particle size of 33 nm, manufactured by Mitsubishi Chemical Co., Ltd.) was prepared, and the surface of the rubber substrate was coated and dried (120 ° C. Heated for 20 minutes) to form a coating layer. Thereby, a transfer belt was obtained. When the static friction coefficient μs of the surface of the transfer belt was measured by the above method, it was 0.34 to 0.82, and when the ten-point average roughness Rz of the surface of the transfer belt was measured by the above method, It was 5 to 11 μm.

(Production of rubber blade)
In the production of the rubber base part, Plaxel 220 (manufactured by Daicel Chemical Industries, 2000, number average molecular weight 2000), which is a bifunctional polyester polyol compound, MDI and 1,3-propanediol / trimethylolethane as a chain length extender ( 80/20) was used as a thermosetting polyurethane, and a rubber base portion of the rubber blade 27 was produced. The polyester polyol in the polyurethane was about 65% by weight.

  In the production of a rubber blade coating layer, 100 parts by weight of ethyl acetate and 20 parts by weight of aromatic diphenylmethane diisocyanate (manufactured by Dainippon Ink & Chemicals, Inc., MDI) were dispersed and mixed in a ball mill for 3 hours to prepare a surface treatment liquid. Prepared. While maintaining this surface treatment liquid at 23 ° C., one surface of the rubber base was immersed in the surface treatment liquid for 10 seconds and then heated in an oven maintained at 50 ° C. for 1 hour to obtain a rubber blade.

(Example 2)
(Preparation of transfer belt)
In the production of the coating layer, the same procedure as in Example 1 was conducted except that 10 parts by weight of Asahi # 80 (carbon black, average primary particle size 22 nm, manufactured by Asahi Carbon Co.) was prepared instead of Mitsubishi Carbon # 30. A transfer belt was prepared. When the static friction coefficient μs of the surface of the transfer belt was measured by the above method, it was 0.4 to 0.9, and when the ten-point average roughness Rz of the surface of the transfer belt was measured by the above method, 1.3 was obtained. ˜10.2 μm.

(Production of rubber blade)
A rubber base part of a rubber blade was produced in the same manner as in Example 1 except that Plaxel 220N (manufactured by Daicel Chemical Industries, Ltd., number average molecular weight 2000) was used instead of Plaxel 220.

Example 3
(Preparation of transfer belt)
The transfer belt was prepared in the same manner as in Example 1 except that 5 parts by weight of Seast S (carbon black, average primary particle size 66 nm, manufactured by Tokai Carbon Co., Ltd.) was prepared instead of Mitsubishi Carbon # 30 in preparation of the surface layer. Was made. The transfer belt had a static friction coefficient μs measured on the surface of the transfer belt of the above-described method, which was 0.38 to 0.8. The ten-point average roughness Rz of the surface of the transfer belt was measured by the above-described method. However, it was 1.6 to 11.2 μm.

(Production of rubber blade)
A rubber blade was produced in the same manner as in Example 2.

Example 4
(Preparation of transfer belt)
A transfer belt was produced in exactly the same manner as in Example 2.

(Production of rubber blade)
A rubber blade was prepared in the same manner as in Example 1, except that PLACCEL 230N (manufactured by Daicel Chemical Industries, Ltd., number average molecular weight 3000) was used, and 1,3-propanediol / polycaprolactone having a molecular weight of 800 was used as the chain extender. A rubber base part was produced. The polyester polyol in the polyurethane was about 65% by weight.

(Example 5)
(Preparation of transfer belt)
A transfer belt was produced in exactly the same manner as in Example 3.

(Production of rubber blade)
A rubber blade was produced in the same manner as in Example 4.

(Comparative Example 1)
(Preparation of transfer belt)
In the production of the coating layer 24B of the transfer belt, Examples were prepared except that 13 parts by weight of Mitsubishi Carbon # 3400B (carbon black, average primary particle size 21 nm, manufactured by Mitsubishi Chemical Corporation) was prepared instead of Mitsubishi Carbon # 30. In the same manner as in Example 1, a transfer belt was produced. When the static friction coefficient μs of the surface of the transfer belt was measured by the above method, it was 0.35 to 0.84, and when the ten-point average roughness Rz of the surface of the transfer belt was measured by the above method, It was 5 to 10.8 μm.

(Production of rubber blade)
A rubber blade was produced in the same manner as in Example 4.

(Comparative Example 2)
(Preparation of transfer belt)
A transfer belt was prepared in the same manner as in Comparative Example 1 except that 20 parts by weight of Mitsubishi Carbon # 3400B (carbon black, average primary particle diameter of 21 nm, manufactured by Mitsubishi Chemical Corporation) was used in preparation of the coating layer of the transfer belt. . When the static friction coefficient μs of the surface of the transfer belt was measured by the above method, it was 0.38 to 0.82, and when the ten-point average roughness Rz of the surface of the transfer belt was measured by the above method, It was 46-11.8 micrometers.

(Production of rubber blade 27)
A rubber blade was produced in the same manner as in Example 2.

(Comparative Example 3)
(Preparation of transfer belt)
A transfer belt was produced in the same manner as in Comparative Example 1.

(Production of rubber blade)
Thermosetting polyurethane using PLACCEL 230 (manufactured by Daicel Chemical Industries, Ltd., number average molecular weight 3000) and a mixture of MDI and 1,3-propanediol / trimethylolethane (80/20) as a chain extender A rubber base part of a rubber blade was prepared in the same manner as in Example 1 except that the polyester polyol in the polyurethane was changed to 75% by weight.

(Comparative Example 4)
(Preparation of transfer belt)
A transfer belt was produced in exactly the same manner as in Example 2.

(Production of rubber blade)
A rubber base part of a rubber blade was prepared in the same manner as in Example 1 except that Plaxel 212 (manufactured by Daicel Chemical Industries, Ltd., number average molecular weight 1250) was used instead of Plaxel 220.

(Comparative Example 5)
(Preparation of transfer belt)
The transfer belt was prepared in the same manner as in Example 3 except that Mitsubishi Carbon # 10 (carbon black, average primary particle diameter 75 nm, manufactured by Mitsubishi Chemical Corporation) was used instead of the seast S in the production of the coating layer of the transfer belt. Was made. When the static friction coefficient μs of the surface of the transfer belt was measured by the above method, it was 0.32 to 0.88, and when the ten-point average roughness Rz of the surface of the transfer belt was measured by the above method, It was 35 to 10.6 μm.

(Test method)
The transfer belts and rubber blades of Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated as follows (1) to (7).

(1) Method for Measuring Residual Electricity of Transfer Belt As shown in FIG. 4, the measurement head 71 supported by the support unit 70 includes a corona discharger 73 and a surface potential meter 75. Above the surface of the transfer belt 24 so that the distance between the corona discharger 73 and the surface potential meter 75 and the surface of the transfer belt 24 supported by the tension roller of each of the examples and comparative examples is 1 (mm). The measurement head 71 is disposed on the surface. Then, while moving the measuring head 71 along the surface of the transfer belt 24, a corona discharge is applied to the surface of the transfer belt 24 by the corona discharger 73, and two seconds later, the surface potential of the place where the corona discharge is applied is changed. The potential measured by the surface potential meter 75 was used as the residual power value. The larger the residual power value, the larger the residual charge and the stronger the dielectric properties. Such a measurement is performed on the transfer belts 24 of Examples 1 to 5 and Comparative Examples 1 to 5 in the initial stage of use, and the transfer belts of Examples 1 to 5 and Comparative Examples 1 to 5 after printing 100K sheets. The remaining power was measured. In both the initial stage of use and after printing 100K sheets, it was judged good when the remaining power was 13 V or more and 62 V or less, and when the remaining power was less than 13 V or larger than 62 V, it was judged as defective.

(2) Paper adsorption at 30 ° C. and 85% In a 30 ° C. and 85% environment, the white pattern was printed with Xerox Premier 60 g / cm paper using an actual machine mounted with the transfer belts of Examples 1 to 5 and Comparative Examples 1 to 5. In the initial stage of use, if a paper jam occurs in front of the fixing unit, or if the leading edge of the paper is bent, it is judged as defective (X), and if none of these occur, it is good ( ○)

(3) Rebound resilience With respect to the rubber blades of Examples 1 to 5 and Comparative Examples 1 to 5, the rebound resilience (Rb) at each temperature was measured by a Rupke rebound resilience test apparatus based on JISK6255.

(4) Sag test About the rubber blade of Examples 1-5 and Comparative Examples 1-5, the value of 100% permanent elongation (100% PS) was measured according to JISK6262. The value of this 100% permanent elongation needs to be 2.0% or less. When this value is larger than 2.0%, the edge portion becomes sag when the rubber blade is used, the linear pressure is lowered, and the cleaning performance of the rubber blade is deteriorated. Therefore, a case where this value is 2.0% or less was judged as good, and a case where this value was larger than 2.0% was judged as bad.

(5) Cleaning Evaluation at 10 ° C. and 10% An experiment was performed in which Solid Pattern was written on the transfer belts of Examples 1 to 5 and Comparative Examples 1 to 5, and then scraped off with a rubber blade. The residual toner remaining on the transfer belt was transferred to a scotch tape and measured with a densitometer, and the quality of cleaning was judged based on the density of the residual toner. The density value of the residual toner was measured using a spectral densitometer X-Rite 528 manufactured by X-Rite. A case where the density value of the residual toner was 0.23 or less was judged as good (O), and a case where the density value of the residual toner was larger than 0.23 was judged as poor (X). Further, when a substantial cleaning evaluation could not be performed, it was determined that measurement was impossible (-).

(6) Coefficient of dynamic friction μ at the tip of the rubber blade in an environment of 30 ° C. and 85%
Regarding the rubber blades 27 of Examples 1 to 5 and Comparative Examples 1 to 5, the rubber blades 27 are moved against the flat stainless steel plate 90 that moves along the arrow DE by the method shown in FIG. 5 in an environment of 30 ° C. and 85%. The tip of was slid so that the contact angle θ was 13 °. At this time, the relative speed between the stainless steel plate 90 and the tip of the rubber blade 27 is 30 mm / second, the surface drag of the stainless steel plate 90 against the tip of the rubber blade 27 is 200 gf, the thickness of the rubber blade 27 is 2 mm, and the rubber The free length F27 (see FIG. 2) of the blade 27 was 8 mm, and the width of the rubber blade 27 (width of the rubber blade 27 in the direction orthogonal to the arrow DE) was 330 mm. Further, as the stainless steel plate 90, one having a surface roughness Ra (similar to JIS B0601 2013) on which the tip of the rubber blade 27 slides of 0.2 μm or more and 1.2 μm or less was used. Further, foreign substances such as oil and lubricant such as Kynar (registered trademark) were substantially not present on the surface of the stainless steel plate 90 and the tip of the rubber blade 27. Then, the dynamic friction force was measured from the pulling force in the direction along the arrow DE of the stainless steel plate 90, and the dynamic friction coefficient μ at the tip of the rubber blade was obtained.

(7) Flip evaluation Under the environment of 30 ° C. and 85%, the transfer conveying apparatus in which the transfer belts and rubber blades of Examples 1 to 5 and Comparative Examples 1 to 5 were set was continuously operated for 2 hours. Then, the case where no flip occurred was judged as good (◯), and the case where flip occurred was judged as bad (x). Moreover, when substantial Flip evaluation could not be performed, it was judged that measurement was impossible (-).

Table 1 below shows various conditions during the production of Examples 1 to 5 and Comparative Examples 1 to 5 and the results of the above evaluation. For Examples 1 to 5, the evaluations of (1), (2), (4), (5), and (7) were all good, whereas for Comparative Examples 1 to 5, the above (1) ) (2) (4) (5) At least one of the evaluations of (7) was defective. For example, in Comparative Example 1, the cleaning evaluation in (5) was poor, and this is considered to be due to the fact that the residual power when the use was continued increased to 85V. In Comparative Example 2, the evaluation of the sheet adsorbing property at 30 ° C. and 85% in (2) was poor. Moreover, about the evaluation of said (3), in Examples 1-5, the rebound resilience value in 10 degreeC was 18% or more and 39% or less, whereas in Comparative Example 3, the repulsion in 10 degreeC. The elasticity value was 41%, and in Comparative Example 4, the rebound resilience value at 10 ° C. was 15%. For this reason, Comparative Example 3 achieves the purpose of enhancing the scraping ability of the rubber blade, but the rubber sag of the rubber blade has deteriorated. Since the friction coefficient in the high-temperature and high-humidity environment of the part was large and the flip occurred during continuous printing, the flip evaluation of (7) was poor. For Comparative Example 5, the evaluation of the sheet adsorbability at 30 ° C. and 85% in (2) was poor.

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 20 ... Transfer conveyance apparatus, 21 ... Transfer roller, 22, 23 ... Stretching roller, 24 ... Transfer belt, 24A ... Rubber base part of transfer belt, 24B ... Coating layer of transfer belt, 25 ... Cleaning part, 27 ... rubber blade, 27A ... rubber base part of rubber blade, 27B ... coating layer of rubber blade, 29 ... holder.

Claims (9)

Multiple rollers,
An endless belt for conveying a transfer material, which is spanned between the plurality of rollers and rotated by the plurality of rollers;
An electric field applying means provided on the back side of the endless belt, wherein the toner image on the image carrier provided on the front side of the endless belt is electrically transferred to the transfer material. A transfer portion having an electric field applying means for applying a transfer electric field to the toner image;
A cleaning unit having a rubber blade for removing toner adhering to the surface of the endless belt;
With
The endless belt has a rubber base portion;
The rubber blade has a rubber base portion,
The surface of the rubber blade is slidable on the surface of the endless belt at the tip of the rubber blade,
2 seconds after applying a 4 kV corona discharge to the surface of the endless belt, the surface potential is 13 V or more and 62 V or less,
The transfer / conveying apparatus, wherein the rubber blade has a rebound resilience value at 10 ° C. of 18% or more and 39% or less.   The transfer / conveying apparatus according to claim 1, wherein the endless belt further includes a coating layer provided on the rubber base portion of the endless belt and defining a surface of the endless belt.   The transfer conveyance device according to claim 1, wherein the rubber blade further includes a coating layer that is provided on the rubber base portion of the rubber blade and defines a surface of the rubber blade.   4. The transfer conveyance device according to claim 2, wherein the coating layer of the endless belt includes carbon black having an average primary particle diameter of 22 nm or more and 66 nm or less.   The transfer conveyance device according to any one of claims 1 to 4, wherein a coefficient of static friction of the surface of the endless belt is 0.4 or more and 0.8 or less.   The transfer conveying apparatus according to any one of claims 1 to 5, wherein the ten-point average roughness of the surface of the endless belt is 1.6 µm or more and 10.2 µm or less.   The dynamic friction coefficient of the tip portion of the rubber blade at a temperature of 30 ° C and a humidity of 85% is 2.6 or more and 5.3 or less, according to any one of claims 1 to 6. Transfer conveyance device.   The transfer conveyance device according to claim 1, wherein the sphericity of the toner constituting the toner image is 0.94 or more.   An image forming apparatus comprising the transfer conveyance device according to claim 1.

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