JP2004264522A - Belt device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt device having a structure which ensures the strength of joint to a belt in order to prevent peeling or break and securely prevents the belt from turning aside or meandering. <P>SOLUTION: The belt device has the belt 3 which is wound round rollers 3A to 3D and forms a spread face H. In the belt device 3, the belt 3 has guide members 32 along its edges which face the end faces of the roller, as viewed from the direction of the width of the belt. The guide members 32 are joined to the surface of a reinforcement member 31 that is stuck in a layer to the surface of the belt 30 and wider than the guide member. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a belt device and an image forming apparatus, and more particularly, to a belt skew or meandering prevention structure.
[0002]
[Prior art]
The belt device has a configuration in which a plurality of rollers and a belt that moves a spread surface using frictional force between the rollers are used. One of the applications is a transfer device in an image forming apparatus or a sheet conveying device. There is a device.
When a belt is used in an image forming apparatus as a transfer device, there is a configuration in which an image on a photosensitive member as an image carrier is transferred to a surface of the belt itself or to a recording sheet adsorbed on the surface. When the image on the photoconductor is transferred to the belt itself, the image on each photoconductor is sequentially transferred to the belt by a primary transfer process to form a superimposed image. A method in which images are sequentially transferred to a recording sheet on which a belt is attracted and conveyed by a batch transfer method in a next transfer step is used. Also, there is a method in which a superimposed image carried on an intermediate transfer body such as a drum is collectively transferred to a sheet adsorbed on a belt instead of a transfer device.
[0003]
When a belt is used as the intermediate transfer member, a structure in which primary transfer for sequentially transferring images to the belt and secondary transfer for collectively transferring superimposed images to a recording sheet are combined, or the recording sheet is attracted to the belt and There is a method in which images are sequentially transferred onto a recording sheet while being transported. Further, a belt may be used as a recording sheet conveying device instead of the intermediate transfer member.
[0004]
By the way, if the degree of parallelism and the outer diameter of the belts around the rollers vary, the tension in the width direction parallel to the axial direction of the rollers will change due to the change in the circumference of the belts, which causes The roller may be deviated in one direction in the axial direction of the roller or meander.
The shift or meandering of the belt causes the transfer position of the images to change, thereby obtaining a defective image in which image misalignment or color misalignment has occurred.
[0005]
Conventionally, as a configuration for preventing the belt from shifting or meandering, a configuration in which a rib serving as a convex portion is bonded to the end in the width direction of the belt (for example, Patent Document 1), There is a configuration in which a reinforcing member is attached to the surface of a corresponding guide member (for example, Patent Document 2).
[0006]
[Patent Document 1]
JP-A-2000-122439 (paragraph "0015" column)
[Patent Document 2]
JP-A-2000-147950 (paragraph "0024" column)
[0007]
[Problems to be solved by the invention]
The rib or guide member adhered to the end of the belt abuts against the end surface of the roller around which the belt is hung, so that the deviation or meandering is regulated, but when the rib or guide member abuts against the roller end surface due to the deviation. As shown by a two-dot chain line in FIG. 9A, the belt A bends in a swelling state, and when the deviation is corrected, the operation of returning to a flat state from this state is repeated. Load may act repeatedly. In the rib or guide (for convenience, indicated by reference numeral G in FIG. 9), the end face where the end face of the roller (for convenience, indicated by reference number C) abuts on the roller and the side opposite to this end face are different in the state of receiving a load. Will be subjected to shearing force.
As a result, as shown in FIG. 9B, when the load is repeatedly applied, if the creep limit of the belt A is exceeded, a crack S or a rupture occurs, which causes deformation or breakage of the belt. Further, when the shearing force is repeatedly applied to the bonding surface, the ribs or the guides are peeled off, so that not only the deviation or the meandering cannot be prevented, but also there is a possibility that the vehicle may run on the rollers. In FIG. 9, when a foreign substance P is mixed between the belt A and the roller C, a convex plastic deformation occurs according to the shape of the foreign substance P. As shown by Q, the convex portion appears in a streak shape, and an abnormal image portion having a streak shape may be formed in a part of the image.
[0008]
On the other hand, the above-mentioned ribs and guides may be in a state in which the belt and the guide are very easily peeled depending on the usage mode. For example, as shown in FIG. 10, a case where a tension roller B for applying tension to the belt A is provided, and the winding angle of the tension roller B around an adjacent roller is increased to prevent slipping or the like. The path of the belt A is bent, and in particular, the direction between the tension roller B and the rollers C and C 'is reversed. In such a case, the belt A bends in accordance with the radius of curvature of the roller B, but the rib or guide (indicated by a symbol G for convenience) as shown in FIGS. The belt is flipped outward from the surface of the belt, and is easily peeled off from the adhesive surface.
[0009]
An object of the present invention is to provide a belt device having a configuration in which in consideration of the above-described problems in the conventional belt device, a structure capable of securing peeling strength and preventing peeling and breakage and reliably preventing displacement and meandering can be secured to a belt. An object of the present invention is to provide an image forming apparatus.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a belt device provided with a belt that can be wound around a plurality of rollers to form an extended surface, wherein the belt has a guide at its widthwise end that can face the end surface of the roller. A member is provided, and the guide member is integrated with the surface of the reinforcing member laminated on the surface of the belt.
[0011]
According to a second aspect of the present invention, in addition to the first aspect, the belt, the reinforcing member, and the guide member are sequentially stacked from the surface of the belt.
[0012]
According to a third aspect of the present invention, in addition to the first or second aspect of the present invention, the belt surface, the reinforcing member, and the guide member are integrally joined at their joining surfaces by bonding.
[0013]
The invention described in claim 4 is characterized in that, in addition to the invention described in any one of claims 1 to 3, the reinforcing member is set wider than the guide member.
[0014]
According to a fifth aspect of the present invention, in addition to the fourth aspect, the reinforcing member is made of a material having adhesive affinity to the belt and the guide member.
[0015]
According to a sixth aspect of the present invention, in addition to the fifth aspect of the invention, the reinforcing member has a joint surface formed of the same material as the material included in the guide member.
[0016]
According to a seventh aspect of the present invention, in addition to the first aspect, the guide member is a member integrally formed of rubber and resin, and the resin is the same as the reinforcing member. It is characterized by being made of a material.
[0017]
According to an eighth aspect of the present invention, in addition to the first aspect, the belt is made of a conductive material-dispersed polyimide resin or polyamideimide resin.
[0018]
According to a ninth aspect of the present invention, in addition to the first aspect of the present invention, the guide member has a seam whose end faces face each other in a circumferential direction of the belt, and It is characterized in that the reinforcing member is arranged at the joint.
[0019]
According to a tenth aspect of the present invention, in addition to the ninth aspect of the present invention, the guide member has an end portion whose end faces are opposed to each other and its vicinity is bonded to the belt with an adhesive, and the guide member has a portion other than the vicinity. The belt is joined to the belt by an adhesive tape.
[0020]
According to an eleventh aspect of the present invention, in addition to the tenth aspect of the present invention, the adhesive used when the guide member is bonded to the belt at the end portion where the end faces of the guide member face each other or in the vicinity thereof is formed of the guide member. It is characterized by being arranged so as not to protrude inward in the width direction.
[0021]
According to a twelfth aspect of the present invention, in addition to the tenth aspect of the present invention, the adhesive used when the guide member is bonded to the belt at the end portion where the end faces of the guide member face each other or in the vicinity thereof is the guide member. Are arranged in such a manner that they protrude outward in the width direction.
[0022]
According to a thirteenth aspect of the present invention, in addition to the one of the ninth to twelfth aspects, the guide member is continuously filled with an adhesive between end faces thereof.
[0023]
According to a fourteenth aspect of the present invention, in addition to the thirteenth aspect, the adhesive filled between the end faces of the guide member is filled by dropping or coating.
[0024]
According to a fifteenth aspect of the present invention, in addition to the thirteenth or fourteenth aspect, the adhesive filled between the end surfaces of the guide member is a one-part, room temperature curing type.
[0025]
According to a sixteenth aspect of the present invention, in addition to the first aspect, the belt is made of a resin material having a Young's modulus of 3000 MPa or more.
[0026]
The invention according to claim 17 is characterized in that the belt device according to one of claims 1 to 16 is used as a transfer device.
[0027]
According to an eighteenth aspect of the present invention, in addition to the seventeenth aspect, the transfer device has a configuration in which a circumferential direction is reversed on a part of a belt expanding surface.
[0028]
According to a nineteenth aspect of the present invention, in addition to the invention of the eighteenth aspect, a roller for imparting a habit of increasing a belt winding angle with respect to the roller is provided as a configuration in which the circumferential direction of the belt is reversed. An image forming apparatus.
[0029]
According to a twentieth aspect of the present invention, in addition to the one of the seventeenth to nineteenth aspects, a plurality of image forming units are arranged along the extended surface of the belt to form a plurality of color images. It is characterized by having a simple configuration.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating a main configuration of an image forming apparatus using a belt device according to an embodiment of the present invention as a transfer device. The image forming apparatus 1 illustrated in FIG. 1 is capable of forming a full-color image. It is a color printer. The present invention can be applied not only to a color printer but also to a facsimile machine, a copying machine or a printing machine which can use an electrostatic recording system or an electrophotographic system.
[0031]
In FIG. 1, the image forming apparatus 1 is provided with a paper feeding unit B below and a paper discharging unit C above the image forming processing unit A installed at the center in the vertical direction.
In the image forming unit A, a plurality of image forming units 2A, 2B, 2C, and 2D are arranged in a horizontal direction, and each of the image forming units 2A to 2D faces and abuts on a photosensitive member of the image forming unit. It faces a primary transfer belt 3 which is a primary transfer body having a possible extending surface.
[0032]
The image forming units 2A to 2D are units capable of forming images of yellow, magenta, cyan, and black used to form a full-color image, and a detailed configuration will be described with reference to one of them. It is as follows. It is needless to say that the other image forming units have the same configuration.
[0033]
In the image forming unit 2A, a photoconductor 4 as a latent image carrier using a drum that can rotate while being in contact with the primary transfer belt 3 is arranged. A charging device 5, a writing device 6, a developing device 7, a primary transfer device 8, and a cleaning device 9 including a blade 9A and a neutralization lamp 9B for executing an image forming process in the rotation process of FIG.
[0034]
The photoreceptor 4 has a structure in which an organic photosensitive layer as a photoconductive substance is provided on the surface of an aluminum cylinder having a diameter of about 30 to 100 mm. The photosensitive member 4 may have an amorphous silicon layer formed on the surface. In the present embodiment, the photosensitive member at the position closest to the roller 3A located on the upstream side in the moving direction of the horizontal expansion surface H of the primary transfer belt 3 is used regardless of whether a full-color or monochrome image is formed. It is designed to be used as a photoreceptor that forms a frequently used black image.
[0035]
The writing device 6 is provided for the photoconductors included in each of the image forming units 2A to 2D, and is provided with a laser light source, a deflecting member using a rotating polygon mirror, and an image forming optical system, although not denoted by reference numerals. Scanning light is radiated to the photosensitive member by a signal from an image forming control unit (not shown) based on the image forming timing between the image forming units.
[0036]
In the image forming units 2A to 2D, a charging process, a writing process, and a developing process for the photoconductor are executed at a preset image forming timing, and the electrostatic latent image formed in the writing process is converted into a visible image in the developing process. When the image is processed and processed, the image is sequentially transferred to the primary transfer belt 3. At the time of transfer, the image is electrostatically transferred by a primary transfer device 8 which is provided inside the orbital area of the primary transfer belt 3 and faces the photoconductor 4 with the primary transfer belt 3 interposed therebetween.
The primary transfer device 8 uses a roller that generates a small amount of ozone, such as at the time of electric discharge, by contacting the back surface of the primary transfer belt 3. The primary transfer device 8 has a polarity opposite to that of the toner used in the developing process and is relatively low. By applying a voltage transfer bias, the toner carried on the photoconductor 4 is electrostatically transferred to the primary transfer belt 3.
[0037]
The photoreceptor 4 after the primary transfer removes residual toner and residual charge on the photoreceptor by a blade 9A and a discharging lamp 9B included in the cleaning device 9, and is prepared for the next image forming process.
[0038]
The primary transfer belt 3 will be described in detail with reference to FIG. 2, but a reinforcing member 31 is joined to a seamless belt base 30 and a guide member 32 is joined to the reinforcing member 31 at an end in the width direction. A belt having a structure, a horizontal spreading surface H is formed by the juxtaposed rollers 3A and 3C, and the belt is wound around a roller 3B whose arrangement position is fixed separately from the rollers 3A and 3C. The surface H moves in the direction indicated by the arrow F.
[0039]
The image forming processing unit A is provided with a secondary transfer belt 12 that forms a secondary transfer body facing the primary transfer belt 3.
The secondary transfer belt 12 is wound around a plurality of rollers 12A to 12D so as to be movable in the direction of the arrow shown in the figure.
On the inner side of the secondary transfer belt 12, a secondary transfer roller 13 is provided so as to face the vicinity of the roller 3A on the primary transfer belt 3 side, and the toner image carried on the primary transfer belt 3 is electrostatically charged. A transfer bias for transfer is applied.
A transfer nip portion is formed between the roller 12B and the transfer roller 13 of the secondary transfer belt 12 while pressing the secondary transfer belt 13 against a roller 3A disposed inside the primary transfer belt 3. ing.
[0040]
The cleaning device 14 removes residual toner from the secondary transfer belt 12. The cleaning device 14 includes a cleaning roller 14A, a blade 14B, and a collection member 14C having the same functions as those of the cleaning device 11 for the primary transfer belt 3, and a unit accommodating these members is a fulcrum shaft. 14D allows the cleaning roller 14A to contact and separate from the secondary transfer belt 12.
[0041]
On the other hand, in the sheet feeding unit B, sheet feeding cassettes 15 and 15 ′ that store sheets as recording media of a plurality of sizes, and feeding rollers 16 and 15 disposed on a sheet feeding side of each sheet feeding cassette. 16 ′ and a registration roller 19 provided at a position where the sheets extracted from each sheet cassette merge.
[0042]
The paper discharge section C includes a fixing device 17 and a paper discharge tray 18 arranged on an extension of the extended surface of the secondary transfer belt 12.
The fixing device 17 includes a pair of heating rollers 17A and 17B opposed to each other with a sheet conveyance path extending on an extension of the extended surface of the secondary transfer belt 12 interposed therebetween.
[0043]
The sheet that has passed through the fixing device 17 is discharged to a discharge tray 18 via a pair of discharge rollers 18A.
[0044]
In the present embodiment, the sheet is discharged so that the image transferred from the primary transfer belt 3 is on the lower side. That is, the sheets stacked on the sheet discharge tray 18 are arranged in such a manner that the pages are arranged in order from the lower side. No post-processing is required. An image forming method for the primary transfer belt 3 and the secondary transfer belt 12 is also set so as to obtain such a discharge mode in which the pages can be aligned. The image forming order on the primary transfer belt 3 is set so that the transferred toner image is an erect image and the toner image transferred from the secondary transfer belt 12 to the sheet is a mirror image. When the first page faces downward, the toner image is directly transferred from the primary transfer belt 3 to the sheet.
[0045]
In the image forming apparatus 1 having the above-described configuration, the image forming units 12A to 12D perform the image forming in accordance with the image forming order set by the image forming control unit (not shown), and the image forming units 12A to 12D perform the image forming on the photosensitive members of the respective image forming units. The carried toner images are sequentially transferred to the primary transfer belt 3 and are superimposed and transferred.
The transfer state of the superimposed transfer image carried on the primary transfer belt 3 with respect to the secondary transfer belt 12 is set according to the mode of single-sided printing or double-sided printing of the sheet.
[0046]
In the image forming mode on both sides of the sheet, the image superimposedly transferred on the primary transfer belt 3 is transferred to the secondary transfer belt 12. In this case, electrostatic transfer is performed by a transfer bias from the secondary transfer roller 13 at a position where the primary transfer belt 3 and the secondary transfer belt 12 are in contact with each other to form a transfer nip.
[0047]
When the transfer to the secondary transfer belt 12 is completed, the primary transfer belt 3 can perform the image transfer by superimposition again after the toner is removed by the cleaning device 11, and the superimposed transfer image is subjected to the primary transfer. The toner image carried on the secondary transfer belt 12 is collectively transferred onto the sheet fed from the paper feeding unit C while being carried on the belt 3.
[0048]
The sheet on which the toner images are collectively transferred is separated from the secondary transfer belt 12 by curvature separation when passing through the roller 12C located on the side of the fixing device 17 among the rollers around which the secondary transfer belt 12 is wound. Then, the toner advances to the fixing device 17, and the toner is melted and permeated by the heating and pressurization by the fixing device 17 to be fixed and discharged to the paper discharge tray 18. When the images transferred on both sides of the sheet are in page order, as described above, the toner image transferred by the primary transfer belt 3 is directed downward in the discharge tray 18 so that the toner image is discharged in the page order. Will be done.
[0049]
On the other hand, in the single-sided printing mode of the sheet, the image transferred to the primary transfer belt 3 only is transferred to the sheet, and the image transferred to the secondary transfer belt 12 is transferred to one side of the sheet. However, in the case of transferring the image on the primary transfer belt 3 side, the image transferred from the photosensitive member of each image forming unit to the primary transfer belt 3 is heated by a roller 3A to the sheet. Is thermally transferred. When the sheet carrying the image by the thermal transfer is discharged to the discharge tray 18, the image surface faces downward, and is discharged in a so-called face-down state.
[0050]
The belt device according to the present embodiment includes a primary transfer belt 3 for performing a primary transfer process and a secondary transfer belt 12 for performing a secondary transfer process in FIG. The transfer belt 3 will be described below.
The primary transfer belt 3 is provided to be hung or wrapped around a plurality of rollers 3A to 3D. In the present embodiment, the roller 3A is used as a driving roller, and the rollers 3B and 3C are used as driven rollers. Is used as an auxiliary roller for increasing the winding angle with respect to the driving roller 3A.
[0051]
The primary transfer belt 3 is stretched between a driving roller 3A and a driven roller 3B, and can move while facing the photoconductor 4 of each image forming unit. Have been.
FIG. 2 is a schematic diagram for explaining the configuration of the primary transfer belt 3. In FIG. 2, the primary transfer belt 3 is opposed to a belt base material 30 and the surface thereof, that is, the peripheral surface of each roller. A reinforcement member 31 and a guide member 32 are sequentially laminated on the surface on the side to be bonded.
[0052]
The belt substrate 30 is made of relatively inexpensive vinylidene fluoride (PVDF), polyimide (PI) in which a conductive agent is dispersed, or polyamideimide (PAI), and has a Young's modulus of 3000 MPa or more. The reason why the conductive agent is dispersed is to obtain resistance characteristics as a transfer body.
By setting such a Young's modulus, even when a foreign substance (indicated by a symbol P in FIG. 9) is mixed between the belt base material 30 and the outer surface of the roller, the elongation is suppressed and irregularities due to plastic deformation are caused. It is possible to prevent the occurrence of streak-like deformation, and to prevent the occurrence of streak-like abnormal portions in the image of this portion when unevenness occurs.
[0053]
The reinforcing member 31 located on the surface of the belt base material 30 has a thickness of about 50 μm, and has a width dimension corresponding to the axial direction of the roller of about 13 mm, which is set to be wider than a guide member 32 described later. Polyethylene terephthalate (PET) is used, and is integrated with the belt substrate 31 via an adhesive tape NT or an adhesive AM.
[0054]
The reinforcing member 31 has a wide width to obtain an adhesive area for securing the adhesive strength to the belt base material 31. Depending on the type of the adhesive, the reinforcing member 31 may be different from the above-described width dimension. However, the width is larger than the width of the guide member 32.
[0055]
The guide member 32 is a long member made of urethane rubber having a width of about 5 mm, which is narrower than the reinforcing member 31 and having a thickness of 0.7 mm, and has the same material as the reinforcing member 31 on its surface. A layer is provided.
As shown in FIG. 3, the guide members 32 are arranged at both ends or one end in the width direction of the belt base 30 along the circumferential direction of the belt base 30, and adhere or adhere to the reinforcing member 31 with an adhesive tape. Are integrated.
[0056]
Regarding the arrangement position of the guide member 32 in the axial direction of the roller, as shown in FIGS. 3 and 4, only the end face of the roller (indicated by reference numeral 3A) is adjacent to the guide member 32 as shown in FIGS. Is configured to be provided at both ends of the belt base material 30 to restrict the deviation or meandering by contacting the axial end surface of the roller.For convenience, as shown by a two-dot chain line in FIG. When the ring members RD are provided at intervals at which the guide member 32 can be positioned at one axial end of the roller 3A, the ring members RD are provided only at one end in the width direction of the belt base material 30 and the end face of the roller 3A and the ring are provided. The structure is such that deviation or meandering is regulated with the end face of the member RD.
[0057]
The reinforcing member 31 is a portion having an adhesion affinity to the belt base material 30 and the guide member 32, that is, a portion capable of securing the adhesive strength. The belt base material 30 uses an adhesive tape NT or an adhesive AM. The bonding strength is ensured by the bonding area when the bonding is performed, and the bonding is performed. The guide member 32 is made of the same material as polyethylene terephthalate (PET) 32A bonded to the rubber surface of the guiding member 32, as shown in FIG. Thus, the adhesive AM having the best adhesive strength is selected and joined. That is, since the joining surfaces of the reinforcing member 31 and the guide member 32 are made of the same material, it is easy to select the type of the adhesive for securing the bonding strength unlike the case of bonding other types of materials. are doing.
[0058]
By providing the reinforcing member 31, even when the guide member 32 made of a dissimilar material cannot be directly joined to the belt base material 31, the belt base material 30 and the reinforcing member 31 are joined with the adhesive strength secured, and The member 32 and the reinforcing member 31 can be integrated with the guide member 32 in a state in which the shear strength is increased with respect to the belt base material 30 by joining the members 32 and the reinforcing member 31 with good adhesiveness due to the same material.
[0059]
On the other hand, in the case where the guide member 32 is joined to the reinforcing member 31 using the adhesive AM, the joining surface, particularly the end on the side opposite to the roller end surface, must be prevented from protruding onto the roller peripheral surface. This is important in preventing the occurrence of deviation or meandering due to the above.
However, since it is relatively difficult to prevent the adhesive AM from protruding over the entire length of the guide member 32 in the longitudinal direction, in the present embodiment, a plan view and a side view of a portion where the guide member 32 is joined As shown in FIGS. 6A and 6B, the guide member 32 is joined with the adhesive AM only at the facing end face or near the end face at the long seam of the guide member 32 (in FIG. As shown in FIG. 6B, the other portions may be joined by an adhesive tape NT. As the adhesive AM in this case, a one-part cold-setting resin is used. For example, Cemedine Super X (trade name of Cemedine Co., Ltd.) is applied to a range of 2 mm from the end face. Nitto 5000N (trade name of Nitto Denko Corporation) is used.
[0060]
At the joint position at the joint end surface, as described above, the adhesive AM is prevented from protruding to the roller end surface side (the side facing the roller end surface indicated by reference numeral 3A in FIG. 6A), while the guide member 32 Protrusion at the end opposite to the roller end surface in the width direction is allowed (indicated by reference numeral 0P in FIG. 6A), and when the adhesive AM is spread over the entire bonding range, the bonding strength can be secured. The above is advantageous.
Further, when joining the joint end surface or its vicinity, the reinforcing member 31 is always located, so that the guide member 32 and the belt base material 30 are integrated.
[0061]
It has been confirmed by experiments of the present inventor that joining with the adhesive AM at the joint end surface can increase the peel strength as compared with the case where the adhesive tape NT is used. As an experiment, a 90 ° peeling method shown in FIG. 7 was used.
Strictly speaking, in this method, it is necessary to rupture the place where the peeling occurred, but when the experiment was performed in a state where the rupture did not occur, the result that the peeling strength was about twice or more as compared with that of the adhesive tape was obtained. .
[0062]
An adhesive AM is filled in the joint end face of the guide member 32 as a method for increasing the peel strength at that portion.
FIG. 8 is a view showing this case. In FIG. 8, a one-part cold-setting type adhesive described above, for example, Cemedine Super X (trade name of Cemedine Co., Ltd.) is provided between the joint end faces of the guide member 32. ) Is filled by dropping or coating to make the end faces of the joints continuous. FIG. 8A is a plan view of a portion where the guide member 32 is joined, and FIG. 8B is a side view of the joined portion.
The filling state in this case is desirably such that there is no protrusion from the end on the roller end face side, as in the case of the adhesive application to the seam end face described above.
[0063]
In the present embodiment, the primary transfer belt 3 shown in FIG. 1 is made of the same material as the reinforcing member 31 via the reinforcing member 31 having an adhesive strength secured to the belt base 30 in the above-described configuration. A guide member 32 having a resin surface is joined. As a result, the guide member 32 is integrated with the belt base 30 in a state where the shear strength is increased even when the guide member 32 cannot be directly joined due to a difference in material from the belt base 30. .
[0064]
Since the belt base material 30 has resistance characteristics as a transfer body, it is difficult to cause uneven plastic deformation by setting the Young's modulus. That is, it is possible to prevent the occurrence of streak-like abnormal portions in an image.
[0065]
The reinforcing member 31 is provided on the joining surface of the guide member 32 with respect to the belt base material 30. Since the joining surface of the guide member 32 and the reinforcing member 31 is made of the same material, the joining strength can be easily secured. Thus, the shear strength of the guide member 32 can be ensured. As a result, the peel strength against the shearing force when contacting the roller end surface can be improved as compared with the case where the guide member 32 is directly joined to the belt base material 31.
The present inventor has determined the peeling strength (by the 90 ° peeling method shown in FIG. 7) of the primary transfer belt 3 formed by laminating the belt base material 30, the reinforcing member 31, and the guide member 32, the generation state of the streak, and the guide. When an experiment was conducted on the peeling of the member 32, the result shown in FIG. 13 was obtained.
[0066]
In FIG. 13, as for the peel strength, as shown in FIG. 1, since the primary transfer belt 3 is used in such a manner that the moving direction is reversed by the roller 3D in the middle of the circumferential direction, the joint end face of the guide member 32 is used. Is repelled outward, but since the joint strength between the reinforcing member 31 at the joint end surface and the joint between the joint end surfaces is made continuous by filling with an adhesive, the joined state is maintained without being repelled. Accordingly, it is possible to prevent the guide member 32 from being separated from the reinforcing member 31.
[0067]
According to the present embodiment, a part of the belt in the circumferential direction is reversed. In other words, the original roller is formed such that the extension surface is linearly formed between the driving roller 3A and the driven roller 3B by the auxiliary roller 3D. Since the transfer unit can be positioned inside the extension surface, the length of the transfer unit can be reduced, and the image forming unit can be downsized in the height direction.
[0068]
【The invention's effect】
According to the first to third and fifth aspects of the present invention, since the guide member is provided on the belt surface via the reinforcing member, the belt is joined via the reinforcing member even when the adhesiveness is poor when different materials are used. be able to. In addition, since the reinforcing member has a configuration having an adhesive affinity with respect to the belt surface and the guide member, it is possible to secure the adhesive strength between the laminated members.
[0069]
According to the fourth aspect of the present invention, since the reinforcing member is wider than the guide member, the adhesive strength to the belt surface can be improved by utilizing the adhesive area, so that a special adhesive structure is not required. Thus, the bonding workability can be improved, and peeling can be prevented by securing the bonding strength with the belt surface.
[0070]
According to the sixth and seventh aspects of the present invention, since the same material surface as the reinforcing member is bonded to the guide member joined to the reinforcing member, a degree of freedom can be obtained in the selection of a material having good adhesiveness. It is possible to use an adhesive capable of improving the adhesive strength.
[0071]
According to the invention of claims 8 and 16, characteristics according to the use of the belt can be set, and the occurrence of unevenness on the surface due to elongation can be prevented, so that foreign matter can be formed between the belt and the roller on which the belt is wound. Even when the particles are mixed, it is possible to suppress the occurrence of irregularities due to foreign matter, to reliably prevent streaks or the like on the image caused by the irregularities, and to prevent the occurrence of defective images.
[0072]
According to the ninth aspect of the present invention, since the reinforcing member is provided at least at the seam of the guide member, it is possible to secure the bonding strength at the seam and prevent the guide member from peeling.
[0073]
According to the tenth aspect of the present invention, only the position where the joint end surfaces of the guide members face each other or the vicinity thereof is joined with an adhesive, and the other parts are joined with an adhesive tape. It is possible to increase the adhesive strength at a position where the adhesive is easily peeled.
[0074]
According to the eleventh and twelfth aspects of the present invention, in the bonding range of the adhesive at the joint end surface of the guide member, the adhesive does not exude to the roller end surface, and the exudation is allowed on the side opposite to the roller end surface. Therefore, it is possible to prevent the guide member from running on the roller due to the deformation of the guide member due to bleeding to the roller end surface side, and to ensure the adhesive strength in the adhesive range by being able to spread the adhesive over the entire adhesive range. Becomes possible.
[0075]
According to the invention as set forth in claims 13 to 15, since the adhesive is filled between the joint end surfaces of the guide member so as to be in a continuous state, it is possible to prevent the end surfaces from being flipped outward and to be able to flow. This makes it possible to reliably prevent the exfoliation of the end face, and furthermore, since the adhesive to be filled at that position is a one-part, room-temperature-curing adhesive, no treatment such as heating and drying is required. Can be improved.
[0076]
According to the seventeenth and eighteenth aspects, even when a part of the belt in the circumferential direction is reversed, the peel strength of the joint end surface of the guide member included in the belt is increased, so that breakage due to peeling or the like occurs. Can be prevented.
[0077]
According to the nineteenth aspect of the present invention, by using a roller for reversing a part of the belt in the circling direction, a part of the belt can be positioned inside the original extended surface, so that the height direction occupied by the beltonga is increased. It is possible to reduce the length of the unit and reduce the size of the unit including the belt.
[0078]
According to the twentieth aspect of the present invention, it is possible to prevent the belt from shifting or meandering, so that it is possible to prevent the occurrence of image position shift and color shift.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a main configuration of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram for explaining a configuration of a primary transfer belt which is a belt device used in the image forming apparatus shown in FIG.
FIG. 3 is a diagram illustrating a state in which a primary transfer belt is wound.
FIG. 4 is a front view of the belt in a running state shown in FIG. 3;
FIG. 5 is a schematic diagram showing a configuration of a guide member joined to the belt shown in FIG.
6A and 6B are views for explaining a joint configuration of a joint portion of the guide member shown in FIG. 2, wherein FIG. 6A is a plan view and FIG. 6B is a side view.
FIG. 7 is a schematic view showing a test method of the peel strength of the guide member shown in FIG.
8A and 8B are schematic views showing another example of a joint state of the joint portion of the guide member shown in FIG. 2, wherein FIG. 8A is a plan view and FIG. 8B is a side view.
9A and 9B are schematic views for explaining an example of a problem in a conventional belt device, wherein FIG. 9A is a front view and FIG. 9B is a plan view.
FIG. 10 is a schematic diagram for explaining an example of a state in which a belt is wound.
FIG. 11 is a schematic view showing an example of a belt loop shown in FIG. 10;
FIG. 12 is a schematic view showing another example of the belt loop shown in FIG. 10;
FIG. 13 is a table showing the results of comparison between the configuration used in the embodiment of the present invention and the conventional configuration regarding peel strength and generation of streaks.
[Explanation of symbols]
1 Image forming apparatus
3 Primary transfer belt
3A-3C roller
3D auxiliary roller
30 Belt base material
31 Reinforcement members
32 Guide member
NT adhesive tape
AM adhesive

Claims (20)

In a belt device including a belt that can be formed around a plurality of rollers to form an extended surface,
The belt is provided with a guide member capable of facing the end face of the roller at a widthwise end thereof, and the guide member is integrated with a reinforcing member surface laminated on the belt surface. Belt device to do. The belt device according to claim 1,
The belt device, wherein the belt, the reinforcing member, and the guide member are sequentially stacked and arranged from the belt surface side. The belt device according to claim 1 or 2,
The belt device, wherein the joining surfaces of the belt surface, the reinforcing member, and the guide member are integrated by an adhesive or an adhesive tape. The belt device according to any one of claims 1 to 3,
The belt device, wherein the reinforcing member is set wider than the guide member. The belt device according to claim 4,
The belt device is characterized in that the reinforcing member is made of a material having an affinity for the belt and the guide member. The belt device according to claim 5,
The belt device according to claim 1, wherein the reinforcing member has the same material portion as a material included in the guide member as a joining surface. The belt device according to any one of claims 1 to 6,
A belt device, wherein the guide member is a member integrally formed of rubber and resin, and the resin is made of the same material as the reinforcing member. The belt device according to any one of claims 1 to 6,
A belt device, wherein the belt is made of a polyimide resin or a polyamide-imide resin in which a conductive material is dispersed. The belt device according to any one of claims 1 to 8,
The belt device, wherein the guide member has a seam whose end faces face each other in a circumferential direction of the belt, and the reinforcing member is arranged at least at the seam portion. The belt device according to claim 9,
A belt device, wherein the guide member has an end portion whose end faces are opposed to each other and the vicinity thereof is bonded to the belt with an adhesive, and a portion other than the vicinity is bonded to the belt with an adhesive tape. . The belt device according to claim 10,
A belt device, wherein an adhesive used when the guide member is adhered to the belt at or near an end where the end surfaces of the guide members face each other is arranged so as not to protrude inward in the width direction of the guide member. . The belt device according to claim 10,
The adhesive used when the guide member is adhered to the belt at or near the end portions where the end surfaces of the guide members face each other is arranged such that the guide member is allowed to protrude outward in the width direction. Features belt device. The belt device according to any one of claims 9 to 12,
A belt device, wherein the guide member is continuous with an end face filled with an adhesive. The belt device according to claim 13,
A belt device, wherein the adhesive filled between the end surfaces of the guide member is filled by dropping or coating. The belt device according to claim 13 or 14,
A belt device, wherein the adhesive filled between the end faces of the guide member is a one-part, room temperature curing type adhesive. The belt device according to any one of claims 1 to 15,
A belt device, wherein the belt is made of a resin material having a Young's modulus of 3000 MPa or more. An image forming apparatus using the belt device according to any one of claims 1 to 16 as a transfer device. The image forming apparatus according to claim 17,
The image forming apparatus according to claim 1, wherein the transfer device has a configuration in which a circumferential direction is reversed on a part of a belt expanding surface. The image forming apparatus according to claim 18,
An image forming apparatus, wherein a roller for imparting a habit of increasing a wrapping angle of the belt with respect to the roller is provided as a configuration in which the circumferential direction of the belt is reversed. The image forming apparatus according to any one of claims 17 to 19,
An image forming apparatus, comprising: a structure in which a plurality of image forming units are arranged along an extension surface of the belt to form a plurality of color images.

Images