JP4940678B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an endless belt having an annular belt body and an image forming apparatus for forming an image composed of a fixed toner image on a recording medium.

  In recent years, image forming apparatuses such as printers and copiers have been widely used, and technologies relating to various elements constituting such image forming apparatuses have also been widely used. Among image forming apparatuses, an image forming apparatus adopting an electrophotographic method exposes the surface of a charged photoreceptor to form an electrostatic latent image, and develops the electrostatic latent image to form a toner image. The image is formed through a series of processes of forming and finally transferring the toner image onto a recording medium at a predetermined transfer position. In such an image forming apparatus, in the above-described image forming process, as a means for transporting the formed toner image to the transfer position or as a means for transporting the recording medium to the transfer position, a plurality of support rolls are stretched. There is an image forming apparatus that employs an endless belt that circulates while being laid. In particular, in an image forming apparatus that forms a color image, it is necessary to superimpose multicolor toner images. Therefore, as a conveying means for conveying the toner image while sequentially receiving the transfer of the toner image formed for each color, or In many cases, the endless belt is used as a conveying means for a recording medium that sequentially receives transfer of toner images formed for each color.

In an image forming apparatus having an endless belt, the rotation shafts of a plurality of support rolls that stretch the endless belt are attached to the image forming apparatus in a state that is slightly shifted from a state that should be parallel to each other due to an error during assembly work. Or the endless belt may run while vibrating in the axial direction of the support roll without moving straight (so-called meandering), because the tension applied to the endless belt varies depending on the position on the endless belt. . When image formation is performed in a state in which the endless belt is shifted due to such meandering, the toner image is shifted from the position where it should originally be transferred when the toner image is transferred onto the recording medium. An image defect occurs in which the image is transferred. In particular, in an image forming apparatus that forms a color image, such a misregistration of the toner image causes a color misregistration or a hue change to the color image formed on the recording medium. In such an image forming apparatus, the occurrence of running deviation of the endless belt becomes a serious problem. Therefore, as a device for preventing the running deviation of the endless belt, it has been proposed to provide a groove on the outer periphery of the support roll and further provide a guide portion that fits into the groove on the surface of the belt body of the endless belt (for example, , See Patent Literature 1 to Patent Literature 3).
Japanese Patent Laid-Open No. 58-1000014 JP-A-4-333457 JP 2003-128295 A

  However, in the endless belt described above, since the force for suppressing the running deviation is concentrated on the belt main body near the base of the guide portion, the belt main body at the base portion of the guide portion easily breaks. For this reason, further ingenuity is required in order to prevent the endless belt from moving and preventing image defects from occurring.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an endless belt and an image forming apparatus that prevent the endless belt from shifting to suppress the occurrence of image defects and exhibit excellent durability.

The endless belt of the present invention for achieving the above object is
An annular belt body;
On the inner peripheral surface of the belt body, a ridge extending along the edge of the belt body is formed. In the ridge, the side closer to the edge of the belt body and the side far from the edge are more rigid. And a high guide part.

  If the guide part is made of a material having the same hardness, the belt body at the base part of the guide part concentrates on the belt body near the base of the guide part, and the force that suppresses the running deviation of the endless belt is concentrated. Is easy to break.

  In the endless belt of the present invention, since the guide portion has higher hardness on the side closer to the edge of the belt body and on the far side, the force for suppressing the running deviation of the endless belt is near the base of the guide portion. Without concentrating, it extends over the entire boundary surface between the guide portion and the belt body, and the belt body is prevented from being broken.

  In the endless belt of the present invention, the protrusion may be composed of a plurality of guide members extending in parallel with the edge of the belt body and having different hardnesses.

  In the endless belt of the present invention, a form in which “the belt body is made of polyimide resin” is a preferable form.

  The polyimide resin is a material that is easy to process and has high durability. By adopting the polyimide resin as a material for the belt main body, an endless belt that does not easily deteriorate or deteriorate is realized.

  In the endless belt of the present invention, a form in which “the belt body is made of a polyamide-imide resin” is also a preferred form.

  Polyamideimide resin is also a material that is easy to process and has high durability. By adopting polyamideimide resin as a material for the belt body, an endless belt that is less likely to deteriorate or deteriorate is realized.

  In the endless belt of the present invention, a form in which “the belt body is made of a polyester resin” is also a preferable form.

  The polyester resin is an inexpensive and easily obtainable material, and the cost can be reduced by adopting the polyester resin as the material of the belt body.

  Further, in the endless belt of the present invention, “the guide portion has a plurality of guide members extending along the edge of the belt main body and having different hardnesses, and the guide member closer to the edge of the belt main body has a higher hardness. A form in which guide members arranged adjacent to each other in the increasing order are bonded to each other is also a preferable form.

  According to such a form, the durability of the guide member is improved.

  Further, in the endless belt of the present invention, “the guide portion extends along the edge of the belt main body and makes a circle around the inner peripheral surface of the belt main body. A plurality of guide members having different hardnesses are arranged in an order in which the guide members closer to the edge of the belt main body have higher hardness, and the connection portions in the extending direction of the guide members are shifted from each other. Is also a preferred form.

  The connection part of the guide member has low durability. Especially, when the position of the connection part of each guide member is in the same position in the direction in which the guide member extends, the places where the durability is low are concentrated. Damage is likely to occur. When the guide portion is damaged, the belt body near the damaged portion is twisted and the belt body is broken. Therefore, the above-described configuration in which the position of the connecting portion of the guide member does not overlap prevents a portion where the durability of the guide member is low from being concentrated on one place and prevents the guide portion from being damaged.

  In the endless belt of the present invention, a form in which “the hardness of the guide portion closest to the edge of the belt body is JIS-A hardness of A75 / S or more” is also a preferable form.

  According to such a form, the durability of the guide member is particularly improved.

  In the endless belt of the present invention, a form in which “the hardness of the guide portion farthest from the edge of the belt body is JIS-A hardness of A45 / S or more” is also a preferable form.

  According to such a form, a flexible guide member is implement | achieved and the concentration of the force which suppresses driving | running | working deviation of an endless belt is eased.

In order to achieve the above object, a first image forming apparatus of the present invention includes:
In an image forming apparatus comprising an image carrier, forming a toner image on the surface of the image carrier, and transferring and fixing the toner image on a recording medium, thereby forming an image composed of a fixed toner image on the recording medium ,
A support member having a roll shape, and having a guide receiver that is recessed from the roll-shaped peripheral surface at an end of the roll shape;
The toner image is transferred onto the recording medium by the transfer of the toner image from the image carrier, and the toner image is circulated and moved between the plurality of support members. An annular belt body that is transported to a position where the belt body is moved, and extends along an edge of the belt body on an inner peripheral surface of the belt body, abuts on the guide receiver of the support member, and contacts the edge of the belt body. An intermediate transfer belt having a guide portion having a higher hardness on the far side is provided between the near side and the far side.

  The first image forming apparatus of the present invention employs the above-described endless belt as an intermediate transfer belt, thereby preventing the intermediate transfer belt from being displaced and suppressing the occurrence of image defects.

In order to achieve the above object, the second image forming apparatus of the present invention provides:
In an image forming apparatus comprising an image carrier, forming a toner image on the surface of the image carrier, and transferring and fixing the toner image on a recording medium, thereby forming an image composed of a fixed toner image on the recording medium ,
A support member having a roll shape, and having a guide receiver that is recessed from the roll-shaped peripheral surface at an end of the roll shape;
An annular shape that is stretched around the plurality of support members and circulates between the plurality of support members with the recording medium placed thereon, and receives the transfer of the toner image onto the recording medium from the image carrier. The belt main body and a ridge extending along the edge of the belt main body on the inner peripheral surface of the belt main body, the ridge being far from the side close to the edge of the belt main body and the far side And a recording medium transport belt having a guide portion having higher hardness on the side.

  The second image forming apparatus of the present invention employs the above-described endless belt as a recording medium conveyance belt, thereby preventing the running deviation of the recording medium conveyance belt and suppressing the occurrence of image defects.

  According to the present invention, the running deviation of the endless belt is prevented, the occurrence of image defects is suppressed, and excellent durability is exhibited.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is an overall configuration diagram of an image forming apparatus according to the present exemplary embodiment.

  The image forming apparatus of this embodiment is a color printer for single-sided output.

  The image forming apparatus 1000 includes image carriers 61Y, 61M, 61C, 61K that carry electrostatic latent images for black (K), cyan (C), magenta (M), and yellow (Y). The electrostatic latent image carried on the image carrier is developed with each color toner to form a toner image of each color, and the toner images are received upon transfer of the formed toner images of each color. Intermediate transfer belt 5 for conveying the toner, primary transfer rolls 50K, 50C, 50M, and 50Y for primary transfer of toner images of respective colors to the intermediate transfer belt 5, and secondary transfer rolls for secondary transfer to paper Pair 9, exposure unit 7 that emits laser light, fixing unit 10 that fixes toner images, and four toner cartridges 4K, 4C, and 4M that replenish toner of each color component to four toner image forming units, respectively. 4Y, the tray 1 storing paper is provided. Here, the intermediate transfer belt 5 circulates and moves in the direction of arrow A in the figure while being stretched between the secondary transfer roll 9b and the drive roll 5a while receiving the drive force from the drive roll 5a. The intermediate transfer belt 5 corresponds to an example of an endless belt according to the present invention.

  Next, an image forming operation in the image forming apparatus 1000 will be described.

  An electrostatic latent image is formed on each of the four image carriers 61Y, 61M, 61C, 61K in response to the laser light emitted from the exposure unit 7, and the formed electrostatic latent images are developed by the developing devices 64K, 64C. , 64M, and 64Y are developed with toners of respective colors to form toner images. The toner images of the respective colors formed in this way are yellow (Y), magenta (M), cyan (C) on the intermediate transfer belt 5 in the primary transfer rolls 50K, 50C, 50M, and 50Y corresponding to the respective colors. ) And black (K) are sequentially transferred and superposed to form a multicolor toner image. The multicolor toner image is conveyed to the secondary transfer roll pair 9 by the intermediate transfer belt 5. On the other hand, in response to the formation of such a multicolor toner image, the sheet is taken out from the tray 1 and conveyed by the conveying roll 3, and the position is adjusted by the registration roll pair 8. Then, the multi-color toner image is transferred onto the conveyed paper by the secondary transfer roll pair 9, and the multi-color toner image is fixed on the paper by the fixing device 10. After the fixing process, the sheet having the multicolor toner image passes through the delivery roll pair 13 and is discharged to the discharge tray 2.

  The above is the description of the image forming operation in the image forming apparatus 1000. In the image formation described above, the intermediate transfer belt 5 plays a role of receiving the transfer of each color toner image and a role of transporting the toner image to the transfer position on the paper, and plays an important role in the image formation.

  In general, in an image forming apparatus that employs such a system that forms a color image via an intermediate transfer belt, the rotation shafts of the secondary transfer roll 9b and the drive roll 5a that stretch the intermediate transfer belt 5 are used during assembly. The intermediate transfer belt does not run straight, but is not parallel to each other due to errors or the tension applied to the intermediate transfer belt varies depending on the position on the intermediate transfer belt. The vehicle may travel (so-called meandering) while vibrating in the axial direction. When image formation is performed in a state where the running transfer of the intermediate transfer belt is caused by such meandering running, when the toner image is transferred onto the paper, the toner image is shifted from the position where it should originally be transferred. The color image is transferred and image defects such as color shift and hue change occur in the formed color image.

  Therefore, in the image forming apparatus 1000, the intermediate transfer belt 5 and the secondary transfer roll 9b, the drive roll 5a, and the primary transfer rolls 50K, 50C, 50M, and 50Y with which the inner surface of the intermediate transfer belt 5 is in contact. A device is provided to prevent the intermediate transfer belt from shifting. Below, the device which prevents this driving | running | working deviation is demonstrated.

  2 shows the structure of the inner peripheral surface of the intermediate transfer belt shown in FIG. 1, and FIG. 3 shows the cross section of the intermediate transfer belt in contact with the tension roll shown in FIG. 1 together with the tension roll. FIG.

  2 shows a part of the inner peripheral surface of the intermediate transfer belt 5, that is, the surface on the side in contact with the secondary transfer roll 9b, the drive roll 5a, and the primary transfer rolls 50K, 50C, 50M, and 50Y. A belt main body 50 and a first guide member 51 and a second guide member 52 provided along both edges of the belt main body 50 are shown. As shown in FIG. 3, the drive roll 5a is provided with steps near both edges of the drive roll 5a, and the intermediate transfer belt 5 is in a state where the first guide member 51 is in contact with the walls of the steps. Run. Further, a step similar to the step provided in the drive roll 5a is also provided in the secondary transfer roll 9b and the primary transfer rolls 50K, 50C, 50M, and 50Y shown in FIG. The intermediate transfer belt 5 travels with the first guide member 51 in contact with the stepped wall.

  As described above, the first guide member 51 with the second guide member 52 behind is provided on the secondary transfer roll 9b, the drive roll 5a, and the primary transfer rolls 50K, 50C, 50M, and 50Y. , The traveling direction of the intermediate transfer belt 5 is limited to the straight traveling direction, and travel deviation is prevented.

  Here, the configurations of the belt main body 50, the first guide member 51, and the second guide member 52 will be described. The belt main body 50 is a belt-like member that has a polyimide resin as a main component and is semiconductive by mixing carbon black, which is a kind of conductive material, in the polyimide resin. Polyimide is a material that is easy to process and has high durability. By adopting polyimide as a main component of the belt main body 50, a belt main body that is unlikely to be deteriorated or deteriorated is realized. Each of the first guide member 51 and the second guide member 52 is a member in which polyurethane elastomer has an elongated shape having a predetermined width and a predetermined thickness. Regarding the first guide member 51 and the second guide member 52, the above-described elongated polyurethane elastomer is an adhesive that elastically deforms, as shown in FIG. 2, one by one along the both edges of the belt body 50. Further, the two ends of each polyurethane elastomer are bonded to each other at the joints 51a and 52a shown in FIG. 2, thereby realizing the configuration shown in FIG.

  Since the joint of the guide member has the lowest durability, when the joints of the two types of guide members are in the same position in the longitudinal direction of FIG. 2 (the direction in which the guide member extends), places with low durability are concentrated. In this position, the guide part is easily damaged. When the guide portion is damaged, the belt body near the damaged portion is twisted and the belt body is broken. Therefore, in the intermediate transfer belt 5 shown in FIG. 2, as can be seen from FIG. 2, the joints 51 a and 52 a are arranged at different positions in the extending direction of the guide member. Ingenuity has been devised so that low-quality parts do not concentrate in one place.

  Further, the first guide member 51 and the second guide member 52 are bonded to each other with an adhesive at the guide boundary 512 shown in FIG. 2, so that the durability of the guide member is improved. The first guide member 51 and the second guide member 52 are both made of polyurethane elastomer, but for the reasons described below, the first guide member 51 and the second guide member 52 have the same hardness. Different polyurethane elastomers are used.

  In general, when a plurality of guide members for preventing running deviation are provided, if these guide members are all made of a material having the same hardness, the innermost guide member (the first guide member 51 in FIG. 2). The force to try to suppress the running deviation is concentrated on the belt body in the vicinity of the boundary line between the guide member provided at the position of the belt) and the belt body (the boundary line corresponding to the boundary line 51b in FIG. 2). The belt body is broken near this boundary. Therefore, in the intermediate transfer belt 5, in order to avoid such breakage of the belt main body, a soft (low hardness) material is adopted for the inner first guide member 51 so as to have flexibility against an external force. The outer second guide member 52 is made of a sturdy (high hardness) material so as to have durability against external force. In this way, by applying a hardness difference between the inner first guide member 51 and the outer second guide member 52, the force applied to the belt main body is dispersed in the degree of concentration, and the first guide member 51 is dispersed. It will start over the entire adhesive surface. As a result, the belt main body is prevented from being broken with such a simple configuration. As will be described later, the hardness of the first guide member 51 is evaluated by JIS-A hardness (type A durometer hardness defined by JIS K6253: 97 “Testing method for hardness of added rubber and thermoplastic rubber”). If the hardness of the first guide member 52 is A75 / S or higher in terms of JIS-A hardness as described above, the concentration of force applied to the belt body is dispersed as described above. Thus, the belt body is prevented from being broken, and an intermediate transfer belt that is difficult to meander is realized by having sufficient hardness. The hardness of the first guide member 51 and the hardness of the second guide member 52 of the intermediate transfer belt 5 satisfy these conditions.

  Here, the JIS-A hardness used in the above description indicates a type A durometer hardness defined in JIS K6253: 1997 “Method for testing hardness of added rubber and thermoplastic rubber”. The hardness of the rubber is expressed by pushing the needle into the surface of the rubber to be measured and deforming it, measuring the amount of deformation and digitizing it. Specifically, it can be measured using a durometer type A ASKER type A manufactured by Kobunshi Keiki Co., Ltd. Moreover, it can measure at 22 degreeC55% RH using the sample accumulated so that it might become sheet-like thickness 6mm for a measurement.

  In the intermediate transfer belt 5 described above, the belt main body 50 has a polyimide resin as a main component, but it is also possible to employ a polyamideimide resin instead of the polyimide resin. An intermediate transfer belt having a belt body mainly composed of polyamideimide resin and an image forming apparatus using the intermediate transfer belt use the above-described intermediate transfer belt 5 and intermediate transfer belt 5 employing polyimide resin. The image forming apparatus 1000 is different from the image forming apparatus 1000 only in the material of the belt body, and redundant description is omitted here. This polyimide imide, like polyimide, is a material that is easy to process and has high durability. By adopting polyamide imide as the main component of the belt body, an intermediate transfer belt that does not easily deteriorate or deteriorate is realized. .

  Further, in the belt body, it is also possible to employ a polyester resin instead of the polyimide resin or the polyamideimide resin. An intermediate transfer belt having a belt body mainly composed of a polyester-based resin and an image forming apparatus using the intermediate transfer belt employ the above-described intermediate transfer belt 5 and intermediate transfer belt 5 that employ a polyimide-based resin. Only the material of the belt main body is different from that of the image forming apparatus 1000, and redundant description is omitted here. Polyester resins have the advantage that they are cheaper and easier to obtain than polyimide resins and polyamideimide resins, and cost reduction can be realized.

  In the above, an example in which the endless belt of the present invention is applied to an intermediate transfer belt has been described. However, the endless belt of the present invention can also be applied to a belt for paper conveyance. Hereinafter, such a sheet conveying belt and an image forming apparatus provided with the sheet conveying belt will be described.

  FIG. 4 is a schematic configuration diagram of an image forming apparatus including a sheet conveying belt.

  The image forming apparatus shown in this figure is a color printer for single-sided output. The image forming apparatus 1000 ′ includes image carriers 21Y, 21M, 21C, and 21K on which toner images of the respective color materials are formed, and chargers 22Y and 22M that uniformly charge the surface of each image carrier to a predetermined potential. , 22C, 22K, exposure units 23Y, 23M, 23C, 23K for irradiating each charger with exposure light to form an electrostatic latent image, and developing the electrostatic latent image with each color toner to form each color toner image Developing units 24Y, 24M, 24C, and 24K, and transfer rolls 27Y, 27M, and 27C provided on the image carriers that carry the paper fed from the paper tray 26 and circulate along the arrangement of the image carriers. , 27K, a sheet conveying belt 5 ′ conveyed to the position of 27K, cleaning blades 210Y, 210M, 210C, 210K for removing toner of each color remaining after the transfer, a toner image on the sheet Fixing device 8 is provided to perform the fixing. Here, the sheet conveying belt 5 ′ is circulated and moved in the direction of arrow B in the figure while being stretched between the stretching roll 5 a ′ and the driving roll 5 b ′ while receiving a driving force from the driving roll 5 b ′. This sheet conveying belt 5 'corresponds to an example of an endless belt according to the present invention.

  Next, the image forming operation in the image forming apparatus 1000 ′ described above will be described.

  In each of the four image carriers 21Y, 21M, 21C, and 21K, an electrostatic latent image is formed by receiving laser light emitted from the exposure units 23Y, 23M, 23C, and 23K, and the formed electrostatic latent images are The developing devices 24Y, 24M, 24C, and 24K are developed with the respective color toners to form toner images. On the other hand, in response to the formation of such a multicolor toner image, the sheet is taken out from the tray 26 and conveyed to the positions of the transfer rolls 27Y, 27M, 27C, and 27K by the intermediate transfer belt 5, and each transfer is performed. A toner image of each color is sequentially transferred at the roll position to form a multicolor toner image on the paper. Further, the multi-color toner image is fixed in the fixing device 28 and discharged to the paper discharge tray 29.

  In the image formation described above, the paper transport belt 5 ′ plays an important role of transporting the paper and receiving the transfer of each color toner image on the paper. When the running deviation of the paper transport belt occurs, the toner image is transferred to a position shifted from the position where the toner image should be transferred when the toner image of each color is transferred onto the paper. Image defects such as color shift and hue change occur. Therefore, in the image forming apparatus 1000 ′, the tension roller 5a ′, the driving roll 5b ′, and the transfer rolls 27Y, 27M, 27C, and 27K that are in contact with the sheet conveying belt 5 ′ and the inner surface of the sheet conveying belt 5 ′. In addition, a mechanism for preventing the running deviation of the sheet conveying belt 5 ′ is provided. This mechanism is the same as the mechanism described in FIGS. By providing such a travel deviation prevention mechanism, in this image forming apparatus 1000 ′, the travel deviation of the recording medium conveyance belt is prevented, and the occurrence of image defects is suppressed.

  Hereinafter, specific experimental data for verifying the effect of the endless belt of the present invention will be described. Here, as a specific example, an experiment is performed by operating an intermediate transfer belt using a polyester resin and an image forming apparatus using the intermediate transfer belt.

  First, the intermediate transfer belt used in this experiment will be described using specific numerical values.

The belt body of the intermediate transfer belt used in this experiment is 100 parts by mass of polyester (crystalline polyester PCTG5445 manufactured by Eastman Chemical Co., Ltd.) and carbon black having a pH of 4.5, which is a kind of conductive agent (Degussa, Germany). The resin composition comprising 16 parts by mass of Printex 140T) and 18 parts by mass of a dispersant (tertiary amino group-containing polymer dispersant Azizpa-PB711 manufactured by Ajinomoto Fine Techno Co., Ltd.) is a material for the belt body. It is used as. This belt body is obtained by extruding such a resin composition into a tube shape with a heating temperature of 260 ° C. by a single screw extruder and processing it into an annular shape having a thickness of 0.13 mm, a width of 350 mm, and an outer diameter of 168 mm. It is formed. The belt body has a surface resistivity of 10 ^11.9 Ω and a volume resistivity of 10 ^10.6 Ωcm.

  The guide member of the intermediate transfer belt used in this experiment is a polyurethane elastomer having an elongated shape with a film thickness of 1.0 mm and a width of 3 mm for both the inner first guide member and the outer second guide member. The first guide member and the second guide member are bonded to a double-sided adhesive sheet (Nitto Denko Corp.) provided with a 0.03 mm thick acrylic resin pressure sensitive adhesive layer on both sides of a 0.1 mm thick nonwoven fabric substrate. ) No. 5000NS) made by pressure, and pressure-bonded along the both edges of the belt body on the inner peripheral surface of the belt body.

  The above is the description of the intermediate transfer belt used in this experiment. The image forming apparatus used in this experiment is an image forming apparatus having the same configuration as that of the image forming apparatus shown in FIG. 1 except for the intermediate transfer belt, and the intermediate transfer belt manufactured by the above method is incorporated therein. Yes.

  Next, the contents of the experiment will be described.

[Experiment 1]
In Experiment 1, an output test of 100,000 identical color images is performed under the following seven conditions to check the occurrence of breakage of the intermediate transfer belt and to inspect the maximum meandering amount of the intermediate transfer belt. In the intermediate transfer belt used in Experiment 1, when the guide member is bonded to the belt body, the position of the joint between the two types of guide members extends as shown in FIG. Bonding is performed so that the positions are different from each other in a certain direction.
(Example 1) Intermediate transfer using polyurethane elastomer with JIS-A hardness A52 / S as the first guide member on the inside and polyurethane elastomer with JIS-A hardness A77 / S as the second guide member on the outside Perform the above output test using a belt.
(Embodiment 2) Intermediate transfer using JIS-A hardness A52 / S polyurethane elastomer for the inner first guide member and JIS-A hardness A61 / S polyurethane elastomer for the second outer guide member Perform the above output test using a belt.
(Example 3) Intermediate transfer using polyurethane elastomer with JIS-A hardness A43 / S as the first guide member on the inside and polyurethane elastomer with JIS-A hardness A77 / S as the second guide member on the outside Perform the above output test using a belt.
(Example 4) Intermediate transfer using polyurethane elastomer with JIS-A hardness A43 / S as the first guide member on the inside, and polyurethane elastomer with JIS-A hardness A70 / S as the second guide member on the outside Perform the above output test using a belt.
(Comparative Example 1) A polyurethane elastomer having a JIS-A hardness A61 / S is adopted for both the inner first guide member and the outer second guide member, and the output test is performed.
(Comparative Example 2) The above output test is performed by adopting a polyurethane elastomer having JIS-A hardness A77 / S for both the first guide member on the inner side and the second guide member on the outer side.
(Comparative Example 3) A polyurethane elastomer having JIS-A hardness A43 / S is adopted for both the inner first guide member and the outer second guide member, and the output test is performed.

  FIG. 5 is a diagram showing the hardness of the inner and outer guide members employed in Examples 1 to 4 and Comparative Examples 1 to 3, and the results of the output test.

Examples 1 to 4 in which the hardness of the inner guide member is lower than the hardness of the outer guide member;
Comparing Comparative Example 1 to Comparative Example 2 in which the hardness of the inner and outer guide members is the same and the hardness is comparable to the hardness of the outer guide members of Example 1 to Example 4, In Examples 1 to 4, no breakage of the intermediate transfer belt was observed, but in Comparative Examples 1 and 2, the belt main body was broken. From this, it can be seen that the belt main body is prevented from being broken by adopting a guide member having a lower hardness than that of the outer guide member as the inner guide member as in the first to fourth embodiments. .

  Further, the hardness of the inner and outer guide members is the same, and the hardness is comparable to the hardness of the inner guide members of Examples 1 to 4, and as described above, In Examples 1 to 4 in which the outer guide member has a hardness difference, no breakage of the intermediate transfer belt is observed, but in Examples 1 to 4, the maximum meandering amount of the intermediate transfer belt is observed. In contrast, in Comparative Example 3, the maximum meandering amount is 1.2 mm, and image defects such as color shift and hue change are feared. Generally, when a soft (low hardness) material is used as the inner guide member, due to its flexibility, the force that shifts the running direction of the intermediate transfer belt is the boundary line between the inner guide member and the belt body (see FIG. 2) (corresponding to the boundary line 51b), the intermediate transfer belt is less likely to break. However, on the other hand, due to its flexibility, the intermediate transfer belt can easily run meandering. The above results reflect this fact, and as in the first to fourth embodiments, a soft (low hardness) material is used as the inner guide member, and the outer guide member is sturdy ( It can be seen that the use of a material having high hardness prevents the intermediate transfer belt from being broken and also suppresses the meandering travel of the intermediate transfer belt.

  Here, in order to estimate the preferable hardness for the outer guide member, the hardness of the inner guide member is A52 / S, which is about the middle as the hardness of the guide member. The maximum meandering amount of Example 1 where the JIS-A hardness of the outer guide member is A77 / S is very small as 0.2 mm, and the JIS-A hardness of the outer guide member is A61 / S. Compared with 0.5 mm of 2, extremely good results are obtained. On the other hand, when Example 3 and Example 4 in which the hardness of the inner guide member is JIS-A hardness A43 / S, which is soft as the hardness of the guide member, are compared, JIS-A of the outer guide member is compared. Example 3 with a hardness of A77 / S has a maximum meandering amount of 0.5 mm (evaluation ◯), and the maximum meandering amount of Example 4 with a JIS-A hardness of the outer guide member of A70 / S of 0.7 mm ( Evaluation △) Better results are obtained. From these results, when evaluated in terms of A5 / S increments, if the JIS-A hardness of the outer guide member is approximately A75 / S or higher, the effect of suppressing meandering of the intermediate transfer belt is great. Recognize.

  Further, when Example 1 and Example 3 in which the JIS-A hardness of the outer guide member is the same value A77 / S are compared, Example 1 in which the JIS-A hardness of the inner guide member is A52 / S is shown. The maximum meandering amount is as small as 0.2 mm, and an extremely good result is obtained as compared with 0.5 mm in Example 3 in which the hardness of the inner guide member is A43 / S. From this result, when evaluated by the A5 / S step hardness, if the JIS-A hardness of the inner guide member is approximately A45 / S or more, the meandering travel of the intermediate transfer belt will be suppressed. Inferred.

  The above is the explanation for Experiment 1. Next, an experiment for verifying the effect of arranging the seam positions of the guide members so as to be different from each other in the extending direction of the guide members as shown in FIG. 2 will be described.

[Experiment 2]
In Experiment 2, an output test of 1 million identical color images is performed under the following two conditions to check the occurrence of breakage of the intermediate transfer belt. In each of the intermediate transfer belts used in Experiment 2, a polyurethane elastomer having JIS-A hardness A52 / S is used for the first inner guide member, and JIS-A hardness A61 is used for the second outer guide member. / S polyurethane elastomer is used.
(Embodiment 5) The color image 100 described above using an intermediate transfer belt that has been bonded so that the seams of the two types of guide members are different from each other in the direction in which the guide members extend. Perform 10,000 sheets of output test.
(Embodiment 6) The above color image 1 million using the intermediate transfer belt bonded so that the joints of the two types of guide members are located at the same position in the extending direction of the guide members. Perform a sheet output test. As a result of performing Experiment 2, in Example 5, the belt body did not break even after outputting 1 million sheets, but in Example 6, there was no problem with the belt body breaking up to 100,000 sheets. However, when the output was repeated, the belt main body was broken at the output number of about 200,000. From this result, as in the fifth embodiment, the positions of the joints of the two types of guide members are arranged so as to be different from each other in the direction in which the guide members extend, thereby reducing the durability of the guide members. It can be seen that the belt does not concentrate in one place and the belt body is prevented from being broken.

  Summarizing the results of Experiment 1 and Experiment 2 above, it is concluded that the intermediate transfer belt can be prevented from being broken by providing a difference in hardness between the inner guide member and the outer guide member. Are arranged at different positions in the extending direction of the guide member, the JIS-A hardness of the outer guide member is A75 / S or more, and the JIS-A hardness of the inner guide member is A45 / S or more. By doing so, it can be seen that the intermediate transfer belt is prevented from being broken and the meandering traveling of the intermediate transfer belt is sufficiently suppressed.

  In the above description, the material of the belt main body employed in the intermediate transfer belt and the paper conveying belt was a polyimide resin, a polyamideimide resin, and a polyester resin, but besides these, a polyurethane resin, Polyamide resins, fluorine resins, etc. can be used.

  In addition to the polyurethane described above, the guide member material used in the intermediate transfer belt and the paper transport belt has an appropriate hardness such as neoprene rubber, polyurethane rubber, silicone rubber, polyester elastomer, chloroprene rubber, and nitrile rubber. The elastic body etc. which have can be employ | adopted. Furthermore, the shape of the guide member is not limited to the substantially rectangular cross section as shown in FIG. 3, and other cross sectional shapes may be adopted. In addition, as the adhesive for adhering the guide member and the belt main body, a pressure-sensitive adhesive, a thermoplastic adhesive, a rubber adhesive, or the like can be used, and an elastically deformable adhesive is particularly preferable.

1 is an overall configuration diagram of an image forming apparatus according to an exemplary embodiment. FIG. 2 is a diagram illustrating a structure of an inner peripheral surface of the intermediate transfer belt illustrated in FIG. 1. FIG. 2 is a diagram illustrating a cross section of an intermediate transfer belt that is in contact with a tension roll illustrated in FIG. 1 together with the tension roll. 1 is a schematic configuration diagram of an image forming apparatus including a sheet conveying belt. It is the figure showing the hardness of the inner and outer guide member employ | adopted by Example 1-Example 4, and Comparative Example 1-Comparative Example 3, and the result of the output test.

Explanation of symbols

1000, 1000 '... Image forming apparatus,
1 ... Tray,
2 ... Output tray,
3 ... transport roll,
4K, 4C, 4M, 4Y ... toner cartridge,
5 ... Intermediate transfer belt,
50 ... belt body,
50K, 50C, 50M, 50Y ... primary transfer roll,
51. First guide member,
52 ... Second guide member,
5a ... Driving roll,
51a, 51b ... seams,
512 ... guide boundary,
5 '... paper transport belt,
5a '... tension roll,
5b '... Driving roll,
61Y, 61M, 61C, 61K ... image carrier,
24K, 24C, 24M, 24Y, 64K, 64C, 64M, 64Y ... developer,
23K, 23C, 23M, 23Y, 7 ... exposed part,
8 ... Registrole vs.
9: Secondary transfer roll pair,
9b ... Secondary transfer roll,
10, 28 ... Fixer,
13: Sending roll pair,
22Y, 22M, 22C, 22K ... charger,
26: Paper tray,
27Y, 27M, 27C, 27K ... transfer roll,
210Y, 210M, 210C, 210K ... cleaning blade,
29 ... Output tray

Claims (2)

  In an image forming apparatus comprising an image carrier, forming a toner image on the surface of the image carrier, and transferring and fixing the toner image on a recording medium, thereby forming an image composed of a fixed toner image on the recording medium ,
  A support member having a roll shape, and having a guide receiver made of a step recessed from the peripheral surface of the roll shape at the end of the roll shape;
  The toner image is transferred from the image carrier, and the transferred toner image is transferred onto the recording medium. An intermediate transfer belt having an annular belt body that conveys to a transfer position and a guide portion that forms a protrusion extending along an edge of the belt body on an inner peripheral surface of the belt body;
  The guide portion is an inner side surface in the width direction of the belt body, and a side surface far from the edge is in contact with a side wall formed on the guide receiver of the support member,
  The image forming apparatus according to claim 1, wherein the guide portion has a lower hardness on a side closer to the edge of the belt body and a side farther from the edge. In an image forming apparatus comprising an image carrier, forming a toner image on the surface of the image carrier, and transferring and fixing the toner image on a recording medium, thereby forming an image composed of a fixed toner image on the recording medium ,
A support member having a roll shape, and having a guide receiver made of a step recessed from the peripheral surface of the roll shape at the end of the roll shape;
An annular shape that is stretched around the plurality of support members and circulates and moves between the plurality of support members with the recording medium placed thereon, and receives the transfer of the toner image onto the recording medium from the image carrier. A recording medium conveyance belt having a belt main body, and a guide portion forming a protrusion extending along an edge of the belt main body on an inner peripheral surface of the belt main body,
The guide portion is an inner side surface in the width direction of the belt body, and a side surface far from the edge is in contact with a side wall formed on the guide receiver of the support member,
The image forming apparatus according to claim 1, wherein the guide portion has a lower hardness on a side closer to the edge of the belt body and a side farther from the edge.

Images