JP2008096814A - Belt, and image forming apparatus provided with belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide stable transfer performance, when a belt is used for an image forming apparatus, in such a manner that the belt is stretched, because a change in the belt width in the axial direction of the belt is small. <P>SOLUTION: The image forming apparatus has: a photoreceptor drum 10; and an intermediate transfer belt 20 coming into contact with the photoreceptor drum 10, so as to be along the shape of the photoreceptor drum 10, in a fixed area, for transferring a toner image from the photoreceptor drum 10. Further, an electrifying device 11 electrifying the photoreceptor drum 10, an exposure device 12 writing an electrostatic latent image on the electrified photoreceptor drum 10, and a rotary type developing device 13 turning a latent image formed on the photoreceptor drum 10 into a visible image with toner are disposed in the image forming apparatus. The intermediate transfer belt 20 has a base material containing an elastic body and a protective layer provided on the base material. In the intermediate transfer belt 20, the reduction rate of the width of the belt when it is stretched in a running direction by 4%, with respect to the width of the belt orthogonal to the running direction when the belt is not stretched is ≤2%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a belt and an image forming apparatus using the belt.

  As a conventional image forming apparatus, for example, a photosensitive drum (image forming carrier) and a visible image formed on the photosensitive drum, which is arranged so as to be able to contact and roll with respect to the photosensitive drum, are formed on paper. A transfer roller or a transfer belt for transferring to a recording material such as the above is known (for example, see Patent Document 1).

  On the other hand, as a color image forming apparatus, for example, an intermediate transfer belt as an intermediate transfer member is disposed opposite to a photosensitive drum, and toner images of respective color components are sequentially primary transferred onto the intermediate transfer belt, and then collectively from the intermediate transfer belt. Those that are transferred to a recording material such as paper are already known. Compared with an image forming apparatus of a direct transfer system, an image forming apparatus using an intermediate transfer system has an advantage of being able to transfer an envelope, a postcard, a label paper or a cardboard regardless of the size.

  In the image forming apparatus using the intermediate transfer method, in order to increase the transfer efficiency in the primary transfer unit, a peripheral speed difference is provided between the photosensitive drum and the intermediate transfer member, and the toner and the photosensitive drum are mechanically separated. There is a method of breaking the adhesion force of the toner by applying a shear force between the two. However, for example, if the peripheral speed of the intermediate transfer belt is made faster than the peripheral speed of the photosensitive drum in the primary transfer portion, the intermediate transfer belt pulls the photosensitive drum due to electrostatic adsorption force, so that the rotational speed of the photosensitive drum varies. This may cause banding (so-called fringe pattern) and color misregistration.

  In this way, if the peripheral speed difference is set to increase the transfer efficiency, banding and color misregistration occur, and the measures to improve the transfer efficiency and the measures to prevent image quality defects conflict, making it difficult to achieve both. Met.

  In order to solve such a problem, for example, an intermediate transfer belt having elasticity is stretched over a plurality of stretching rolls, and a contact area between the intermediate transfer belt and the photosensitive drum is increased, so that a conventional image is obtained. Compared to the forming apparatus, it has become possible to achieve higher transfer efficiency and higher image quality (see, for example, Patent Document 2).

  Normally, in an image forming apparatus using an intermediate transfer belt, a mark made of a material having a reflectance different from that of the belt surface is formed on the intermediate transfer belt. (See, for example, Patent Document 3).

  However, in the case of an image forming apparatus that uses an intermediate transfer belt that is stretched over a stretch roll, the belt width in the axial direction decreases due to the expansion in the circumferential direction, and the mark fluctuates outside the sensor reading range. there were. In addition, an image forming apparatus that changes the interval between stretch rolls in order to keep the belt tension and belt resistance constant even if the belt width in the axial direction is predicted and the mark on the belt is formed (for example, patent In the case of Document 4), the belt width in the axial direction always changes due to fluctuations in the expansion ratio. As a countermeasure against the belt width change described above, it is conceivable to form a mark that is long in the axial direction on the belt. However, when the mark is formed in the image area, the entire belt surface cannot be used as an intermediate transfer member.

  Moreover, the possibility of belt meandering increases due to the reduction in the axial belt width. As a countermeasure, a meandering prevention measure such as a belt rib can be considered, but the cost increases.

JP-A-63-301960 JP 2003-84581 A Japanese Patent Laid-Open No. 11-15297 JP-A-9-90781

  The present invention aims to solve the above technical problem. That is, an object of the present invention is to provide a belt capable of obtaining good image quality with little change in the belt axial width even when the belt is stretched, and an image forming apparatus including the belt.

  The above-mentioned subject is achieved by the following present invention. That is, the belt and the image forming apparatus of the present invention have the following characteristics.

  (1) It has a base material containing an elastic body and a protective layer provided on the base material, and the belt width is 4% in the running direction with respect to the belt width perpendicular to the running direction when not stretched. A belt whose belt width reduction rate is 2% or less.

  (2) The belt has a mark made of a material having a reflectance different from that of the belt surface, and the mark when stretched by 4% in the running direction with respect to the width of the mark perpendicular to the running direction when not stretched. The belt according to (1), wherein the width reduction rate of the belt is 50% or less.

  (3) An image carrier that forms an electrostatic latent image according to image information, a developing device that visualizes the electrostatic latent image formed on the image carrier as a toner image with toner, and the toner image is transferred An intermediate transfer member that carries the toner image, and a transfer device that transfers the toner image carried on the intermediate transfer member to a recording medium. The intermediate transfer member according to (1) or (2) An image forming apparatus comprising the belt described above.

  (4) The belt has a mark made of a material having a reflectance different from that of the surface thereof, a mark detection device for detecting the mark, and image writing or paper based on a signal detected by the mark detection device. The image forming apparatus according to (3), further comprising: a control unit that performs position alignment.

  According to the present invention, it is possible to provide an image forming apparatus in which the change in the belt width in the axial direction of the belt is small, and when the belt is extended and used, stable transfer performance can be obtained easily and reliably at all times. it can.

  Embodiments of the present invention will be described below. In describing the embodiment of the present invention in detail, the belt of the present invention will be described in detail, and then the image forming apparatus of the present invention will be described.

<Belt>
The belt of the present invention has a base material containing an elastic body and a protective layer provided on the base material, and 4% in the running direction with respect to the belt width perpendicular to the running direction when not stretched. A reduction rate of the belt width at the time of extension is 2% or less.

  As described above, even when the belt of the present invention is stretched, since the change in the width of the belt is very small, the belt is installed in the image forming apparatus and the stretched state is continued. However, it is possible to prevent the mark from being detected, and as a result, it may be difficult to perform image writing or sheet alignment.

  On the other hand, if the belt width reduction rate exceeds 2%, it is necessary to increase the belt width in anticipation of the reduction in the belt width when designing an image forming apparatus equipped with the belt.

  Here, “when not stretched” means a state where no external stress is applied to the belt, and “when stretched 4%” means 4% stretched in the circumferential direction with respect to the belt. Refers to the state.

  More specifically, two metal shafts are put on the inner peripheral surface of the belt, and the two metal shafts are moved to appropriate positions so that the inner peripheral length of the belt is extended by 4% with respect to the non-expanded state. This indicates a state of elongation by 4%.

  If the belt is formed with a mark made of a material having a different reflectance from the belt surface, the mark width in the axial direction is reduced by 4% compared to the mark width in the axial direction when not stretched. The rate is 50% or less.

  The case of no elongation and 4% elongation is the same as described above. If the mark width reduction rate exceeds 50%, it is difficult or impossible to detect a mark by a mark detection device provided in an image forming apparatus, which will be described later, and it becomes difficult to perform image writing and paper alignment. There is a risk. For example, if the belt mark width is 10 mm and the mark width decreases by more than 50%, the mark width becomes less than 5 mm. On the other hand, the sheet width orthogonal to the traveling direction of A4 sheet is 256 mm, and the sheet width orthogonal to the traveling direction of B3 sheet is 340 mm. For example, infrared light is not irradiated on the mark, and the mark cannot be detected. As a result, it may be difficult to write an image or align paper.

-Belt layer structure-
The configuration of the belt of the present invention will be described. Although the belt is not particularly limited, it is preferable that the belt includes an elastic belt base 201 and a protective layer 202 covering the surface of the belt base 201 as shown in FIG. Note that the protective layer 202 may be provided on one side or both sides of the substrate 201 depending on the purpose.

  The belt base 201 is preferably a layer composed of an elastic body (elastic material), and further preferably has a conductive agent dispersed therein. The elastic body (elastic material) refers to a material that can be restored to its original shape even when deformed by applying an external force of 100 Pa.

  The material forming the elastic material is a diene-based or non-diene-based rubber elastic body, and the rubber elastic body material may be either solid or liquid, such as acrylic rubber, isoprene rubber, butadiene rubber, Examples include ethylene-propylene copolymer rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, epichlorohydrin copolymer rubber, urethane rubber, silicone rubber, butyl rubber, chloroprene rubber, norbornene, and hydrogenated polybutadiene rubber. Among these, ethylene- More preferred are propylene copolymer rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, epichlorohydrin copolymer rubber, and chloroprene rubber. One or more of the above elastic materials can be used in a blend. The belt width reduction rate can be controlled by the degree of crosslinking in the elastic material at the time of belt formation, and the belt width reduction rate can be reduced as the degree of crosslinking is lower.

  If necessary, materials that can be usually added to rubber, such as softeners, plasticizers, curing agents, vulcanizing agents, vulcanization accelerators, anti-aging agents, fillers such as silica and calcium carbonate, and the like may be added.

  As the crosslinking agent, for example, sulfur, sulfur compounds, organic peroxides, silane coupling agents and the like can be used. Preferred crosslinking agents include sulfur “# 200” (Tsurumi Chemical Co., Ltd.), perbutyl P (Nippon Yushi), and the like. Can be used. Further, as the vulcanization accelerator, for example, an aldehyde-ammonia type, aldehyde-amine type, thiourea type, guanidine type, thiazole type, sulfenamide type, thiuram type, dithiocarbamate type vulcanization accelerator should be used. Preferred vulcanization accelerators include tetramethylthiuram monosulfide (“Noxeller TS” manufactured by Ouchi Shinsei Chemical Co., Ltd.), a thiuram vulcanization accelerator, and 1,3-di-o, a guanidine vulcanization accelerator. -Tolyl guanidine ("Noxeller DT" made by Ouchi Shinsei Chemical Co., Ltd.)

  As the conductive agent, conductive or semiconductive fine powder can be used, and there is no particular limitation as long as a desired electric resistance can be stably obtained. However, carbon black such as ketjen black and acetylene black, aluminum and the like Examples thereof include metals such as nickel, conductive metal oxides such as tin oxide, and potassium titanate. Among these, carbon black and conductive metal oxides are preferable. These may be used alone or in combination. In order to reduce the belt width reduction rate, it is preferable to select a conductive agent with small aggregation among the conductive agents. It is also possible to add an ion conductive material such as LiCl, or a conductive polymer material such as polyaniline, polypyrrole, polysulfone, or polyacetylene. These may be used alone or in combination.

  Examples of the carbon black include “Asahi Thermal” (manufactured by Asahi Carbon Co., Ltd.) (average particle diameter of 80 nm), “Seast SP” (manufactured by Tokai Carbon Co., Ltd.) (average particle diameter of 95 nm), and the like as acetylene black. Examples of ketjen black include “Ketjen Black EC” (manufactured by Lion Corporation) (average particle size: 34 nm). Since these carbon blacks have different cohesiveness and different resistance values, they are preferably mixed and added as appropriate.

  As content of this electrically conductive agent, it is preferable to contain 10-80 weight% with respect to 100 weight part of materials of an elastic body, and it is still more preferable to contain 15-50 weight%. By setting it within the above range, the intermediate transfer belt can be given a desired volume resistance value and can also be given a function as a reinforcing agent.

  The content of the crosslinking agent is preferably 0.1 to 5% by weight based on 100 parts by weight of the elastic material. By setting it within the above range, the belt base material itself can be softened, and a reduction in the width of the belt base material when stretched in the running direction can be suppressed.

  The content of the vulcanization accelerator is preferably 0.5 to 5% by weight with respect to 100 parts by weight of the elastic material. By making it within the above range, the belt base material itself can be softened more reliably, and the reduction of the belt base material width when extending in the running direction can be suppressed.

  The thickness of the belt substrate 201 varies depending on the use of the belt, the material used and the formulation, but is usually preferably in the range of 300 to 900 μm, more preferably in the range of 300 to 800 μm, 400 More preferably, it is in the range of ˜700 μm. If the thickness of the belt base material is less than 300 μm, the strength of the belt may not be sufficient, and the belt may be broken due to rotation or the like. If the thickness exceeds 900 μm, the belt may be unusable due to increased resistance and hardness.

  The protective layer 202 is a layer that is provided so that the back surface is in contact with the front surface of the belt base material 201 and constitutes the outermost layer of the belt.

Examples of the material forming the protective layer material include urethane resin, polyester, phenol, acrylic, polyurethane, epoxy resin, and cellulose. The protective layer may contain conductive or semiconductive fine powder. The particulate conductive agent as the conductive or semiconductive fine powder preferably has a particle diameter of 3 μm or less and a volume resistivity of 10 ⁹ Ωcm or less. For example, fine particles made of metal oxides such as tin oxide, titanium oxide, and zinc oxide or alloys thereof, or carbon black such as ketjen black and acetylene black can be used. The addition amount of the conductive or semiconductive fine powder is preferably 0 to 30% by weight with respect to 100 parts by weight of the main coating material material in order to control the resistance value of the belt. More preferably, it is contained in an amount of 0 to 15% by weight.

  Further, a fluorine-based or silicone-based resin or fine particles may be added to the protective layer. Further, a coupling agent may be added to improve the adhesion with the belt base material 201.

  The thickness of the protective layer 202 is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 15 μm or less. If the thickness of the protective layer is less than 1 μm, the surface layer may be lost due to wear, and if it exceeds 15 μm, the crack width increases and crack ghost cannot be suppressed. The thickness of the protective layer 202 can be controlled by the coating amount on the base material 201. Note that the belt width reduction rate can be controlled by changing the thickness of the protective layer within the above range.

  The film thickness of the belt was measured by using an eddy current type film thickness meter CTR-1500E manufactured by Sanko Electronics Co., Ltd., and the same sample was measured five times, and the average value was defined as the belt film thickness.

  In addition, a mark made of a material having a reflectance different from that of the belt surface is formed on the belt, specifically, on the non-image image portion other than the image portion that receives the toner image transfer in the vicinity of both ends of the belt. In this case, examples of the mark include a mark hole and a metal reflection film.

  In the case of forming an image by superimposing the toners of the respective colors, by forming the mark, it is possible to detect the timing of writing out the toner images of the respective colors, so that it is possible to correct the positional deviation with higher accuracy. Corresponding to these marks, sensors as mark detection devices are arranged in the vicinity of the belt. As the sensor 13, for example, a reflective sensor is used. For example, a configuration in which infrared light is irradiated onto a belt and reflected light from a mark is detected by a photodiode can be used. The signal detected by the photodiode is obtained as a signal indicating different output levels from the difference between the reflectance of the mark and the reflectance of the belt surface material. By processing the signal, for example, the mark is detected. It is possible to obtain a TTL signal whose portion is a Hi output. From this signal, the difference in mark detection timing between the image carrier on the most upstream side and the most downstream side in the running direction (conveyance direction) is obtained, and this is used to calculate the belt running corresponding to the reference distance between the rotation axes of the image carrier. By comparing with the required time, the actual distance between the rotation axes of the image carrier can be obtained, whereby the Y margin can be obtained. The obtained result is sent to an exposure apparatus for forming an electrostatic latent image, and the Y margin is corrected by correcting the irradiation timing of the exposure light.

-Production of belts-
For the production of the belt, a known method can be appropriately selected and used. In particular, a method in which an extruded material is coated on a metal pipe and vulcanized to form an endless shape is preferably used. The belt of the present invention can also be produced by performing peroxide crosslinking, forming a base material by adding an additive, and forming a protective layer on the surface thereof by a coating method.

−Physical properties of belt−
In the belt of the present invention, the surface roughness Rz (10-point average roughness) specified in JIS-0601 (2001) is preferably 10 μm or less, and more preferably 8 μm or less. In addition, although a lower limit is not necessarily limited, it is preferable that it is 1.0 micrometer or more from a viewpoint of adhesiveness with the opposing member. Further, when the belt 20 is normally brought into contact with the photosensitive drum 10 by the image forming apparatus, the permanent elongation specified in JIS-K6262 (1997) is preferably 10% or less, and more preferably 5% or less. It is preferable. The belt resistance value is preferably in the range of 10 ⁷ to 10 ¹¹ Ωcm in a non-stretched state from the viewpoint of transfer performance. The volume resistivity of the belt is performed as follows. In the examples described later, the measurement is performed by the same measurement method as described above.

(Volume resistivity and their measurement)
Here, the volume resistivity can be measured according to JIS K 6911 (1995) using a circular electrode (for example, Hiresta UPMCP-450 UR probe manufactured by Dia Instruments Co., Ltd.). A method for measuring the volume resistivity will be described with reference to the drawings. FIG. 4 consists of FIG. 1A of a schematic plane showing an example of a circular electrode and FIG. 4B of a schematic cross section. The circular electrode shown in FIG. 4 includes a first voltage application electrode A and a second voltage application electrode B. The first voltage application electrode A has a cylindrical electrode portion C and a cylindrical ring electrode having an inner diameter larger than the outer diameter of the cylindrical electrode portion C and surrounding the cylindrical electrode portion C at a constant interval. Part D is provided. An intermediate transfer belt T is sandwiched between the cylindrical electrode portion C and ring electrode portion D of the first voltage application electrode A and the second voltage application electrode B, and the cylindrical electrode portion C of the first voltage application electrode A The current I (A) that flows when the voltage V (V) is applied between the second voltage application electrode B and the volume resistivity ρv (Ωcm) of the volume resistivity of the belt is calculated by the following formula. be able to. Here, in the following formula, t represents the thickness of the belt.
Formula: ρv = 19.6 × (V / I) × t

<Image forming apparatus>
Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.

  The image forming apparatus of the present invention includes the above-described belt of the present invention. The belt is preferably used as an intermediate transfer belt or a paper transport belt in the image forming apparatus.

  When the belt according to the present invention is provided in an image forming apparatus as an intermediate transfer belt, the intermediate transfer belt is stretched around a plurality of stretching rolls and arranged in contact with the shape of the image carrier, and the image carrier and It is a preferable aspect that the image forming apparatus has a configuration in which one of the intermediate transfer belts is used as a drive source and the other is driven to rotate.

  First, an image forming apparatus (an image forming apparatus of the present invention) provided with the belt of the present invention as an intermediate transfer belt will be described.

  FIG. 2 is a schematic configuration diagram showing an embodiment of the image forming apparatus of the present invention.

  In FIG. 2, an image forming apparatus according to an example of the present invention includes a photosensitive drum (image carrier) 10 and a photosensitive drum in a predetermined area on the photosensitive drum 10 in order to transfer a toner image from the photosensitive drum 10. And an intermediate transfer belt 20 in contact with each other so as to follow the 10 shape. In the present embodiment, the photosensitive drum 10 includes a photosensitive layer whose resistance value is reduced by light irradiation. Around the photosensitive drum 10, a charging device 11 for charging the photosensitive drum 10 and , An exposure device 12 for writing an electrostatic latent image of each color component (in this example, black, yellow, magenta, cyan) on the charged photosensitive drum 10, and each color component latent image formed on the photosensitive drum 10. A rotary developing device 13 that visualizes an image with each color component toner, an intermediate transfer belt 20, and a cleaning device 17 that cleans residual toner on the photosensitive drum 10 are disposed.

  Here, as the charging device 11, for example, a charging roll is used, but a charging device such as a corotron may be used.

  The exposure device 12 may be any device that can write an image on the photosensitive drum 10 by light. For example, a print head using an LED is used, but the present invention is not limited to this, and a print head using an EL. However, a scanner that scans a laser beam with a polygon mirror may be selected as appropriate.

  Further, the rotary type developing device 13 is rotatably mounted with developing units 13a to 13d in which the respective color component toners are accommodated. For example, each color component toner is placed on a portion of the photosensitive drum 10 where the potential is reduced by exposure. The toner to be used is not particularly limited in shape, particle size, etc., and any toner can be used as long as it is accurately placed on the electrostatic latent image on the photosensitive drum 10, From the viewpoint of obtaining good image quality, it is preferable to use a spherical toner.

  In this example, the rotary developing device 13 is used, but four developing devices may be used.

  The cleaning device 17 may be appropriately selected as long as it cleans the residual toner on the photosensitive drum 10 and employs a blade cleaning method.

  However, there may be a mode in which the cleaning device 17 is not used when, for example, spherical toner is used with high transfer efficiency.

  In the present embodiment, the intermediate transfer belt 20 is stretched around four stretching rolls 21 to 24, and is disposed on the surface of the photosensitive drum 10 positioned between the rotary developing device 13 and the cleaning device 17. Only a predetermined contact area is arranged in close contact with each other.

  Of the four tension rolls 21 to 24 of the intermediate transfer belt 20, the tension roll 21 positioned on the upstream side of the transfer position functions as, for example, a drive roll, and the winding angle of the intermediate transfer belt 20 is the largest. Is set. Further, the tension roll 22 positioned on the downstream side of the transfer position is a driven roll and regulates a contact area with the photosensitive drum 10. Further, the stretching roll 23 located downstream thereof is a driven roll, and also serves as a back roll (grounded in this example) for secondary transfer. Is a driven roll, for example, also serving as a backup roll for the belt cleaning device 27.

  In this example, the sizes of the four tension rolls 21 to 24 may be appropriately selected.

  In this example, since the intermediate transfer belt 20 and the photosensitive drum (image carrier) 10 are disposed in contact with each other over a relatively wide range along the circumferential surface, the intermediate transfer belt 20 and the photosensitive drum 10 are arranged. It is possible to take a system in which one of the driving sources is driven and the other is driven to rotate. For example, the intermediate transfer belt 20 can be driven to rotate using the photosensitive drum 10 as a drive source. In the case of this method, one drive mechanism can be omitted, and the apparatus can be reduced in size and cost.

  Further, the intermediate transfer belt 20 and the photosensitive drum 10 may be driven by separate drive systems.

  A primary transfer roll 25 as a primary transfer device is disposed in contact with a part of the contact area where the intermediate transfer belt 20 is in close contact with the photosensitive drum 10 from the back side of the intermediate transfer belt 20, and a predetermined primary transfer bias is applied. Has been. Further, a secondary transfer roll 30 as a secondary transfer device is disposed opposite to the tension roll 22 of the intermediate transfer belt 20 with the tension roll 22 as a backup roll. For example, the secondary transfer roll A predetermined secondary transfer bias is applied to 30 and a stretching roll 23 that also serves as a backup roll is grounded.

  A recording material 40 such as paper is accommodated in a supply tray 41, supplied by a feed roll 42, and then guided to a secondary transfer site via a transport roll 43 and a resist roll 44, and a fixing roll 46 and a pressure roll. 47 is conveyed to a fixing device 45 having the number 47.

  Next, the operation of the image forming apparatus of the present invention shown in FIG. 2 will be described. The respective color component toner images are sequentially formed on the photosensitive drum 10, sequentially transferred to the intermediate transfer belt 20 through the contact area (primary transfer position), and then collectively transferred to the recording medium 40 at the secondary transfer position. In such an image forming process, the photosensitive drum 10 and the intermediate transfer belt 20 are arranged in contact with each other in a relatively wide contact area and are elastically pressed by the intermediate transfer belt 20 having elasticity. The nip (tack) surface pressure between the body drum 10 and the intermediate transfer belt 20 is not so high, and the toner image is wrapped by the elastic intermediate transfer belt 20 so that the toner image on the photoreceptor drum 10 is encased. Is primarily transferred to the intermediate transfer belt 20 side. At this time, the transfer image onto the intermediate transfer belt 20 is not defective in image quality such as a holo character due to a large nip surface pressure, and is transferred with high transfer efficiency. Therefore, the color image quality on the recording medium 40 is kept extremely good. It is.

  Next, an image forming apparatus (an image forming apparatus of the present invention) provided with the belt of the present invention as an intermediate transfer belt or a sheet conveying belt will be described.

  FIG. 3 is a schematic configuration diagram showing another embodiment of the image forming apparatus of the present invention.

  As shown in FIG. 3, an image forming apparatus according to another example of the present invention includes a photosensitive drum (image carrier) 6 and a belt 1 facing the photosensitive drum (image carrier) 6, and a toner image formed on the photosensitive drum 6. Is transferred to the recording material 7 ′ on the belt (intermediate transfer belt) 1 or the belt (transfer conveying belt) 1 ′.

  Here, in an embodiment in which the belt 1 is used as an intermediate transfer belt, as shown in FIG. 3, after the toner image on the photosensitive drum 6 is primarily transferred to the belt 1 by the primary transfer device 8a, the toner on the belt 1 is then transferred. The image is secondarily transferred to the recording material 7 such as paper by the secondary transfer device 8b.

  On the other hand, in the embodiment in which the belt 1 is used as a conveying belt, as shown in FIG. 3, after the recording material 7 ′ is held on the belt 1 ′, the toner image on the photosensitive drum 6 is transferred to the belt 1 by the transfer device 8. Transfer to 'Upper recording material 7'.

  In the image forming apparatus shown in FIG. 3, it is preferable that the belt 1 is stretched around a plurality of stretching rolls 9 and is arranged in contact with the drum-shaped photosensitive drum 6.

  According to the present aspect, by causing the belt 1 to follow the shape of the photosensitive drum 6 as much as possible, discharge due to useless gaps before and after the nip area during transfer can be eliminated, and scattering of the toner image can be prevented. Further, it is advantageous for the paper peeling performance from the photoconductor.

  Further, in the image forming apparatus shown in FIG. 3, it is preferable that one of the photosensitive drum (image carrier) 6 and the belt 1 is used as a drive source and the other is driven to rotate.

  By adopting such a drive configuration, one drive mechanism can be omitted, and accordingly, the drive cost can be reduced, and the thickness of the belt 1 resulting from the drive interference between the belt 1 and the photosensitive drum 6 can be reduced. Variation factors such as variations and feed variations in the process direction can be excluded.

  In the image forming apparatus of the present invention, it is preferable to extend and use the belt in order to suppress the undulation of the belt and the instability of the nip with the photosensitive drum (image carrier) or the transfer roll. . In particular, as described above, in order to follow and rotate the image carrier and the belt, a certain degree of extension is required.

  Therefore, in the image forming apparatus of the present invention, it is preferable to use the belt of the present invention at an elongation rate in the range of 1 to 10%, and more preferably in the range of 4 to 10%.

  Here, when the stretch rate exceeds 10%, a crack may occur in the protective layer of the belt, and a good image quality may not be obtained.

[Preferred embodiment]
<1> A belt in which the reduction width of the belt in the axial direction when the belt is stretched by 4% in the circumferential direction is 2% or less before stretching.

  <2> The belt according to <1>, wherein the belt includes a base material layer formed of an elastic body and a protective layer formed on the base material layer.

  <3> The belt has a mark made of a material having a reflectance different from that of the surface thereof, and has a width of the mark in the axial direction when extended by 4% with respect to the width of the mark in the axial direction when not extended. The belt according to <1> or <2>, wherein the reduction rate is 50% or less.

<4> The belt according to any one of <1> to <3>, wherein the volume resistivity is in a range of 10 ⁷ to 10 ¹¹ Ωcm.

  <5> An image carrier that forms an electrostatic latent image according to image information, a developing device that visualizes the electrostatic latent image formed on the image carrier as a toner image with toner, and the toner image is transferred An intermediate transfer member that carries the toner image, and a transfer device that transfers the toner image carried on the intermediate transfer member to a recording medium. The intermediate transfer member includes the above-described items <1> to <4>. An image forming apparatus comprising any one of the belts.

  <6> The image according to <5>, further comprising: a mark detection device that detects a mark; and a control unit that performs image writing and paper positioning based on a signal detected by the mark detection device. Forming device.

  <7> The intermediate transfer belt is stretched by a plurality of stretching rolls, and is arranged in contact with the shape of a drum-shaped image carrier, and either the image carrier or the intermediate transfer member is used as a drive source. The image forming apparatus according to <5> or <6>, wherein the other is driven to rotate.

  <8> The image forming apparatus according to <5> to <7>, wherein the intermediate transfer belt is used at an expansion rate of 4% to 10%.

  <9> An image forming apparatus having an image carrier and a conveyance belt facing the image carrier, wherein the belt according to any one of <1> to <4> is used as a conveyance belt.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “part” represents “part by weight”.

<Example 1>
(Preparation of belt substrate)
Polychloroprene rubber Chloroprene rubber (ES-40, manufactured by Denki Kagaku Kogyo Co., Ltd.) 75 parts by weight, Epichlorohydrin copolymer (Zeklon 3106, manufactured by Nippon Zeon Co., Ltd.) 25 parts by weight, Carbon ("Asahi Thermal" manufactured by Asahi Carbon Co., Ltd., average particle 30 parts by weight (diameter 80 nm), 8 parts by weight of Ketjen Black EC (manufactured by Lion Corporation, average particle diameter 34 nm), 5 parts by weight of zinc oxide (Zinc Hana 1, Nippon Chemical Industry), magnesium oxide (Kyowa Mag 150, Kyowa Chemical Industry) 5 parts by weight, process oil (Diana PW-150, Idemitsu Kosan) 10 parts by weight, sulfur (# 200, Tsurumi Chemical) 0.5 parts by weight, vulcanization accelerator (Noxeller TS, Ouchi Shinsei Chemical Industry) 0.5 parts by weight) and vulcanization accelerator (Noxeller DT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 0.5 parts by weight are kneaded and then extrusion molded. Coated on a metal pipe, it was subjected to steam vulcanization at 1 hour vulcanizer at 0.99 ° C.. Further, the belt after vulcanization was finished to a thickness of 500 μm by grinding the front and back sides with a cylindrical grinder.

(Preparation of protective layer)
The surface of the obtained belt base material was spray-coated with urethane resin “JLY-601ESD” (manufactured by Japan Atchison), and then heated at 120 ° C. for 30 minutes to form a protective layer having a thickness of 15 μm.

<Example 2>
(Preparation of belt substrate)
Polychloroprene rubber Chloroprene rubber (ES-40, manufactured by Denki Kagaku Kogyo Co., Ltd.) 75 parts by weight, Epichlorohydrin copolymer (Zeklon 3106, manufactured by Nippon Zeon Co., Ltd.) 25 parts by weight, Carbon ("Seast SP" manufactured by Tokai Carbon Co., Ltd., average particle 30 parts by weight (diameter 95 nm), 8 parts by weight of Ketjen Black EC (manufactured by Lion Corporation, average particle diameter 34 nm), 5 parts by weight of zinc oxide (Zinc Hana 1, Nippon Chemical Industry), magnesium oxide (Kyowa Mag 150, Kyowa Chemical Industry) 5 parts by weight, process oil (Diana PW-150, Idemitsu Kosan) 10 parts by weight, sulfur (# 200, Tsurumi Chemical) 1 part by weight, vulcanization accelerator (Noxeller TS, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) ) 1 part by weight, vulcanization accelerator (Noxeller DT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 0.5 part by weight, and after extrusion, metal Was coated type were steam-vulcanized at 1 hour vulcanizer at 0.99 ° C.. Further, the belt after vulcanization was finished to a thickness of 500 μm by grinding the front and back sides with a cylindrical grinder.

(Preparation of protective layer)
The surface of the obtained belt base material was spray-coated with urethane resin “JLY-601ESD” (manufactured by Japan Atchison), and then heated at 120 ° C. for 30 minutes to form a protective layer having a thickness of 15 μm.

<Example 3>
(Preparation of belt substrate)
Polychloroprene rubber Chloroprene rubber (ES-40, manufactured by Denki Kagaku Kogyo) 75 parts by weight, Epichlorohydrin copolymer (Zeklon 3106, manufactured by Nippon Zeon) 25 parts by weight, Carbon (Asahi Thermal, manufactured by Asahi Carbon Co., Ltd.) 30 parts by weight , Ketjen Black EC (manufactured by Lion) 8 parts by weight, zinc oxide (Zinc Hana 1, Nippon Chemical Industry) 5 parts by weight, magnesium oxide (Kyowa Mag 150, Kyowa Chemical Industry Co., Ltd.) 5 parts by weight, process oil (Diana 10 parts by weight of PW-150, Idemitsu Kosan Co., Ltd., 1 part by weight of sulfur (# 200, Tsurumi Chemical Industry), 1 part by weight of vulcanization accelerator (Noxeller TS, manufactured by Ouchi Shinsei Chemical Co., Ltd.), vulcanization accelerator (Noxeller) (DT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) After kneading 0.5 parts by weight, it was extruded and coated on a metal pipe, and vulcanized at 150 ° C for 1 hour. It was carried out air vulcanization. Further, the belt after vulcanization was finished to a thickness of 500 μm by grinding the front and back sides with a cylindrical grinder.

(Preparation of protective layer)
The surface of the obtained belt base material was spray-coated with urethane resin “JLY-601ESD” (manufactured by Japan Atchison Co., Ltd.), and then heated at 120 ° C. for 30 minutes to form a protective layer having a thickness of 5 μm.

<Example 4>
(Preparation of belt substrate)
Polychloroprene rubber Chloroprene rubber (ES-40, manufactured by Denki Kagaku Kogyo) 75 parts by weight, Epichlorohydrin copolymer (Zeklon 3106, manufactured by Nippon Zeon) 25 parts by weight, Carbon (Asahi Thermal, manufactured by Asahi Carbon Co., Ltd.) 30 parts by weight , 8 parts by weight of Ketjen Black EC (Lion), 5 parts by weight of zinc oxide (Zinc Hana 1, Nippon Chemical Industry), 5 parts by weight of magnesium oxide (Kyowa Mag 150, manufactured by Kyowa Chemical Industry), process oil (Diana) PW-150, Idemitsu Kosan Co., Ltd. 10 parts by weight, perbutyl P (manufactured by Nippon Oil & Fats) 1 part by weight, extruded and coated on a metal pipe, and steam vulcanized with a vulcanizer at 150 ° C. for 1 hour. Further, the belt after vulcanization was finished to a thickness of 500 μm by grinding the front and back sides with a cylindrical grinder.

(Preparation of protective layer)
The surface of the obtained belt base material was spray-coated with urethane resin “JLY-601ESD” (manufactured by Japan Atchison Co., Ltd.), and then heated at 120 ° C. for 30 minutes to form a protective layer having a thickness of 5 μm.

<Example 5>
In Example 1, an intermediate transfer belt was prepared according to Example 1 except that the steam vulcanization was performed in a vulcanization can at 165 ° C. for 30 minutes in the vulcanization process at the time of production of the belt base material.

<Example 6> In Example 3, an intermediate transfer belt was prepared according to Example 3 except that in the vulcanization process at the time of belt base material production, steam vulcanization was performed at 160 ° C for 40 minutes in a vulcanization can. Produced.

<Example 7>
(Preparation of belt substrate)
Polychloroprene rubber Chloroprene rubber (ES-40, manufactured by Denki Kagaku Kogyo Co., Ltd.) 75 parts by weight, Epichlorohydrin copolymer (Zeklon 3106, manufactured by Nippon Zeon Co., Ltd.) 25 parts by weight, Carbon (Asahi Thermal, manufactured by Asahi Carbon Co., Ltd.) 30 parts by weight , Ketjen Black EC (manufactured by Lion) 8 parts by weight, zinc oxide (Zinc Hana 1, Nippon Chemical Industry) 5 parts by weight, magnesium oxide (Kyowa Mag 150, Kyowa Chemical Industry Co., Ltd.) 5 parts by weight, process oil (Diana 10 parts by weight of PW-150, Idemitsu Kosan Co., Ltd., 1 part by weight of sulfur (# 200, Tsurumi Chemical Industry), 1 part by weight of vulcanization accelerator (Noxeller TS, manufactured by Ouchi Shinsei Chemical Co., Ltd.), vulcanization accelerator (Noxeller) (DT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) After kneading 0.5 parts by weight, it was extruded and coated on a metal pipe, and vulcanized at 150 ° C for 1 hour. It was carried out air vulcanization. Further, the belt after vulcanization was finished to a thickness of 500 μm by grinding the front and back sides with a cylindrical grinder.

(Preparation of protective layer)
On the surface of the obtained belt base material, urethane resin “JLY-601ESD” (manufactured by Japan Atchison Co., Ltd.), carbon black (“Asahi Thermal” manufactured by Asahi Carbon Co., Ltd.) and 10 parts by weight and a softening agent (“Fukol Aromax”). "Made by Fuji Kosan Co., Ltd.) 5 parts by weight was spray coated and then heated at 120 ° C for 30 minutes to form a protective layer having a thickness of 2 µm.

<Comparative Example 1>
(Preparation of belt substrate)
Polychloroprene rubber Chloroprene rubber (ES-40, manufactured by Denki Kagaku Kogyo Co., Ltd.) 75 parts by weight, Epichlorohydrin copolymer (Zeklon 3106, manufactured by Nippon Zeon Co., Ltd.) 25 parts by weight, Carbon ("Asahi Thermal" manufactured by Asahi Carbon Co., Ltd., average particle 30 parts by weight (diameter 80 nm), 8 parts by weight of Ketjen Black EC (manufactured by Lion Corporation, average particle diameter 34 nm), 5 parts by weight of zinc oxide (Zinc Hana 1, Nippon Chemical Industry), magnesium oxide (Kyowa Mag 150, Kyowa Chemical Industry) 5 parts by weight, process oil (Diana PW-150, Idemitsu Kosan) 10 parts by weight, sulfur (# 200, Tsurumi Chemical) 1 part by weight, vulcanization accelerator (Noxeller TS, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) ) 1 part by weight, vulcanization accelerator (Noxeller DT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 0.5 part by weight, and after extrusion, metal Was coated type were steam-vulcanized at 1 hour vulcanizer at 0.99 ° C.. Further, the belt after vulcanization was finished to a thickness of 500 μm by grinding the front and back sides with a cylindrical grinder.

(Preparation of protective layer)
The surface of the obtained belt base material was spray-coated with urethane resin “JLY-601ESD” (manufactured by Japan Atchison), and then heated at 120 ° C. for 30 minutes to form a protective layer having a thickness of 15 μm.

<Comparative example 2>
(Preparation of belt substrate)
Polychloroprene rubber Chloroprene rubber (ES-40, manufactured by Denki Kagaku Kogyo Co., Ltd.) 75 parts by weight, Epichlorohydrin copolymer (Zeklon 3106, manufactured by Nippon Zeon Co., Ltd.) 25 parts by weight, Carbon ("Asahi Thermal" manufactured by Asahi Carbon Co., Ltd., average particle 30 parts by weight (diameter 80 nm), 8 parts by weight of Ketjen Black EC (manufactured by Lion Corporation, average particle diameter 34 nm), 5 parts by weight of zinc oxide (Zinc Hana 1, Nippon Chemical Industry), hard clay (Union Clay RC-1, Takehara Chemical Industry) 20 parts by weight, magnesium oxide (Kyowa Mag 150, manufactured by Kyowa Chemical Industry Co., Ltd.) 5 parts by weight, process oil (Diana PW-150, Idemitsu Kosan) 10 parts by weight, sulfur (# 200, Tsurumi Chemical Industry) 1 part by weight Parts, vulcanization accelerator (Noxeller TS, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1 part by weight, vulcanization accelerator (Noxeller DT, large After Ri Shinko Chemical Industrial Co., Ltd.) and kneaded with 0.5 parts by weight, and applied onto a metal pipe by extrusion molding were steam-vulcanized at 1 hour vulcanizer at 0.99 ° C.. Further, the belt after vulcanization was finished to a thickness of 500 μm by grinding the front and back sides with a cylindrical grinder.

(Preparation of protective layer)
The surface of the obtained belt base material was spray-coated with urethane resin “JLY-601ESD” (manufactured by Japan Atchison), and then heated at 120 ° C. for 30 minutes to form a protective layer having a thickness of 15 μm.

<Evaluation of belt reduction width>
When the belt is stretched by 4% in the circumferential direction, the evaluation of the reduction width of the belt in the axial direction is performed by stretching the belt with two metal rolls of Φ12 under the environment of 22 ° C. and 55% RH. The width of belt reduction was determined by the method described above. Further, the belt extension rate was varied by changing the interval between the two metal rolls.
(Equation 1)
[Belt reduction width (%)] = ([Belt width when not stretched] − [Belt width when stretched]) × 100 / [Belt width when not stretched] Formula (1)

<Evaluation of actual machine>
Using the intermediate transfer belts of Examples 1 to 7 and Comparative Examples 1 and 2, experiments were conducted with the following configurations in order to grasp the running performance. The basic process is the same as that shown in FIG.
(conditions)
Photoconductor: OPC photosensitive material Process speed: 80 mm / s
Developer: Docu Center Color 400CP developer developer carrier manufactured by Fuji Xerox Co., Ltd .: Aluminium hollow pipe with a diameter of 15 mm and alumite treatment Image forming member: Silicon having a hardness of 50 degrees on a 0.5 mm thick SUS plate Primary transfer device with rubber set to doctor method: Roll primary transfer with a semiconductive sponge layer of φ15 mm and volume resistance of 10 ⁸ Ωcm: 9-12 μA (constant current control)
Secondary transfer apparatus: φ20 mm, volume resistance 10 ⁸ Ωcm, roll latent image potential provided with foamable silicon rubber layer containing ionic conductive agent: −100 V
Background potential: -350V
Intermediate transfer belt: The inner peripheral surfaces of Examples 1 to 3 and Comparative Examples 1 and 2 were stretched by 4% with a roll, stretched, driven by a belt driven by a photosensitive drum, and a contact width of 30 mm.
Position detection mark: A 9 mm square position detection mark was attached to the non-image area on the outer peripheral surface of the intermediate transfer belts of Examples 1 to 3 and Comparative Examples 1 and 2.
Fixing device: φ40 mm hollow type heat lamp using SUS material with a thickness of 0.5 mm: Tungsten lamp pressure roll with a rating of 650 W: φ30 mm SUS cylinder covered with a rubber layer with a thickness of 50 mm Recording material: Fuji Xerox Office supply company C2 paper (running evaluation)
The running evaluation was performed by running 10,000 images with an image area coverage of 5% on an actual machine. The number of vehicles that can run was used as the evaluation result.

  Table 1 shows the belt reduction width evaluation results and the running evaluation results.

  As shown in Table 1, when the belt reduction width at the time of 4% elongation is 2% or less, belt meandering or the like does not occur, so that the actual machine can run without the position detection mark being detached from the sensor. On the other hand, when the belt reduction width exceeds 2%, belt meandering occurs and the position detection mark is detached from the sensor, so that it is not possible to run on the actual machine. Further, even if the range that can be detected by the sensor is expanded, if the belt width decrease is large, if the number of sheets is increased, the belt meandering becomes large and it is impossible to run the actual machine. Further, the hardness of the belt base material is controlled by the amount of carbon black contained in the belt base material, the content of the vulcanizing agent and the vulcanization accelerator, the vulcanization time and the vulcanization temperature, and the thickness and thickness of the protective layer. By controlling the hardness of the protective layer depending on the presence or absence of additives, the belt reduction width at 4% elongation can be reduced to 2% or less.

  Examples of use of the present invention include copying machines using electrophotography, image forming apparatuses such as printers, financial terminals (banknote transport, card transport), automatic ticket gates (ticket / commuter pass transport), card readers, etc. There is application.

FIG. 3 is a schematic cross-sectional view showing an embodiment of a layer configuration of the intermediate transfer belt of the present invention. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus of the present invention. It is a schematic block diagram which shows other one Embodiment of the image forming apparatus of this invention. It is a figure explaining the measuring method of surface resistivity.

Explanation of symbols

  201 belt substrate, 202 protective layer, 10 photosensitive drum, 11 charging device, 12 exposure device, 13 rotary developing device, 13a, 13b, 13c, 13d developing device, 17, 27 cleaning device, 20 intermediate transfer belt, 21 , 22, 23, 24 Stretch roll, 25 Primary transfer roll, 30 Secondary transfer roll, 40 Recording material, 42 Feed roll, 43 Transport roll, 44 Registration roll, 45 Fixing device, 46 Fixing roll, 47 Pressure roll.

Claims (3)

  A base material containing an elastic body and a protective layer provided on the base material, and the belt width when stretched by 4% in the running direction relative to the belt width perpendicular to the running direction when not stretched. A belt having a reduction rate of 2% or less. An image carrier that forms an electrostatic latent image according to image information, a developing device that visualizes the electrostatic latent image formed on the image carrier as a toner image with toner, and the toner image transferred to the toner An intermediate transfer member carrying an image, and a transfer device for transferring the toner image carried on the intermediate transfer member to a recording medium,
An image forming apparatus comprising the belt according to claim 1 on the intermediate transfer member. The belt has a mark made of a material having a reflectance different from that of the surface,
A mark detection device for detecting a mark;
The image forming apparatus according to claim 2, further comprising: a control unit that performs image writing and sheet alignment based on a signal detected by the mark detection device.

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