JP2009271422A - Endless belt, belt device, intermediate transfer unit, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt being belt material which is not affected by magnetic powder used as carrier in a developing device, prevents adverse effect on a formed image by the magnetic powder and is free from detection infeasibleness caused by erasion of a marker due to staining or rubbing of the belt such as in optical detection even when applied as the belt base material of an intermediate transfer belt in the image forming apparatus, and to provide the intermediate transfer belt. <P>SOLUTION: In the endless belt having a joining part where the ends of a sheet are superposed and joined to be endless, magnetic materials are arranged in the joining part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intermediate transfer unit used as an intermediate transfer member of a full-color copying machine or printer that transfers a full-color image onto a transfer material after a toner image is superimposed on an intermediate transfer member to form a full-color image. The present invention relates to an endless belt that can be used for a unit and an image forming apparatus including such an intermediate transfer unit.

  When a full-color image is obtained in an image forming apparatus such as a copying machine or a printer, a toner image of each color is formed on a photosensitive member, and sequentially transferred onto an intermediate transfer belt, which is an intermediate transfer member, so that multiple colors are formed on the intermediate transfer belt. After the image is formed, it is electrostatically transferred again onto the transfer material to form a multicolor image with no image shift, and the toner transferred onto the transfer material in this way is heated and thermally fixed. It is known to fix.

  Recently, with respect to such a member, a flexible belt has been used in many cases due to the freedom of layout.

  Here, in order to achieve the above-described “multicolor image without image displacement”, it is necessary to set the rotation of the belt to a predetermined speed and to prevent fluctuations. For that purpose, the speed of the belt is required. Need to be detected.

  Here, as such a technique, a detection position mark is attached to the belt, and the rotation of the belt is optically detected using the detection position mark (Japanese Patent Laid-Open No. 2003-233285 (Patent Document 1), JP-A-2004-29085 (Patent Document 2) and JP-A-2004-226888 (Patent Document 3) and the like, and a through hole is provided in the belt or a part integrated with the belt. Techniques for optically detecting the belt speed by using them (Japanese Patent Laid-Open No. 2004-99248 (Patent Document 4), Japanese Patent Laid-Open No. 2004-262571 (Patent Document 5), Japanese Patent Laid-Open No. 2006-17975 (Patent Document 6)) Is mentioned.

  However, when the toner adheres and is contaminated, the transmitted light amount and reflected light amount are not correctly detected. As a result, the accurate position detection of the belt, which is required when dealing with the high image quality particularly required in a color image, The synchronization timing may not be detected.

  Further, when forming the belt, there is an increase in the number of steps for providing the mark and the through hole, and the ablation process used for providing the accurate through hole is complicated and has a problem that the cost is significantly increased.

  As a technique for solving such a problem, in Japanese Patent Application Laid-Open No. 2007-78972 (Patent Document 7) by the present inventors, an intermediate transfer belt is accurately measured by a magnetic force generator fixed to a belt member or a magnetized magnetic material. Techniques for performing position detection and synchronization timing detection have been proposed.

However, in a color image forming apparatus provided with a developing device that uses magnetic powder as a carrier in the image developer, even if the sealing performance is improved, the magnetic powder is present somewhat, and the intermediate transfer belt Accumulated in the magnetized area, preventing accurate position detection and synchronization timing detection of the above intermediate transfer belt, or the accumulated magnetic powder falling off and fixing together with the transfer image on the intermediate transfer belt As a result, there arises a problem that the image finally formed is soiled.
JP2003-233285A JP 2004-29085 A JP 2004-226888 A JP 2004-99248 A JP 2004-262571 A JP 2006-17975 A JP 2007-78972 A JP 2007-93503 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to provide a magnetic powder used as a carrier in a developing device even when applied as a belt base material for an intermediate transfer belt of an image forming apparatus. Endless belts that are not affected by the magnetic field, do not adversely affect the image formed by the magnetic powder, and are also undetectable due to disappearance of markers due to smearing of the belt such as optical detection. An object of the present invention is to provide such an intermediate transfer belt.

  The inventors of the present invention have previously proposed a method of manufacturing a belt base material in which end portions of sheets are overlapped and joined endlessly, as disclosed in JP-A-2007-93503 (Patent Document 8). According to this method, productivity of a belt base material that has been conventionally produced by combining a mold and a centrifugal method can be remarkably improved.

  By further improving this method, even when applied as a belt base material for an intermediate transfer belt of an image forming apparatus, it is not affected by the magnetic powder used as a carrier in the developing device, and the formation of such magnetic powder. It has been found that an endless belt can be easily obtained as a belt material that does not adversely affect an image and that is not undetectable due to disappearance of a marker due to smearing of the belt such as optical detection. It came to.

  That is, in order to solve the above-mentioned problem, the endless belt according to the present invention is an endless belt having a joining portion in which end portions of sheets are joined in an endless manner as described in claim 1, wherein the magnetic material is It is an endless belt characterized by being arranged in a joined part.

  Further, the endless belt of the present invention is the endless belt according to claim 1, wherein the magnetic body is a powder and dispersed in the adhesive used for the joining as described in claim 2. It is characterized by.

  According to a third aspect of the present invention, there is provided a belt device comprising: an intermediate transfer belt comprising the endless belt according to the first or second aspect; and a plurality of suspension members for rotatably suspending the intermediate transfer belt. In addition, the belt device is characterized in that a magnetism detecting means for detecting the magnetism of the magnetic material is provided in the vicinity of the intermediate transfer belt.

  According to a fourth aspect of the present invention, an intermediate transfer unit is provided with the belt device according to the third aspect.

  According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising the intermediate transfer device according to the fourth aspect.

  According to the endless belt of the present invention or the belt using the endless belt of the present invention as a belt material, when the endless belt of the belt device is suspended by a plurality of suspension members that are rotatably suspended, the endless belt is disposed near the endless belt. By providing magnetic detection means for detecting the magnetism of the magnetic material, it is possible to respond to belt position detection and synchronization timing accuracy required for high image quality without being affected by dirt and the like. . Furthermore, since the magnetic body is arranged at the joining portion where the end portions of the sheets are overlapped and joined endlessly, it is easy to manufacture, no special device is required, and the magnetic body is not exposed to the outside. Moreover, since loss due to wear or the like is prevented in advance, it can be reliably detected.

  In addition, even when applied as a belt base material for an intermediate transfer belt of an image forming apparatus, the magnetic powder used in the developing apparatus is not affected, and the magnetic powder does not adversely affect the formed image.

  According to the endless belt according to claim 2, since the magnetic body is a powder and is dispersed in the adhesive used for the bonding, the magnetic powder is added to the adhesive. Therefore, the manufacturing cost can be kept low because it can be manufactured without changing other manufacturing methods, and the flexibility of the obtained endless belt is not partially lost.

  According to the belt device of the present invention, the intermediate transfer belt constituted by the endless belt as described above, a plurality of suspension members for rotatably suspending the intermediate transfer belt, and the magnetic material near the intermediate transfer belt. Since magnetic detection means for detecting magnetism is provided, it is possible to cope with belt position detection and synchronization timing. Furthermore, unlike optical detection, there is no detection due to the disappearance of markers due to the smearing of the belt, and the magnetic material is arranged at the joint where the two ends of the rectangular sheet are overlapped and joined endlessly. Since it is not exposed to the outside, loss due to wear or the like is prevented in advance, so that it can be reliably detected and is not affected by the magnetic powder used as a carrier in the developing device, and such magnetic powder There is also no contamination of the formed image due to the accumulation of.

  Since the intermediate transfer unit of the present invention includes the above-described excellent belt device, accurate intermediate transfer can be performed over a long period of time, and image quality can be improved without image contamination.

  Since the image forming apparatus of the present invention includes the above-described intermediate transfer unit, the image quality can be improved over a long period of time, and image contamination does not occur.

  The endless belt used in the present invention is an endless belt having a joining portion in which end portions of sheets are overlapped and joined in an endless manner, and a magnetic body is arranged at the joining portion.

  Here, when the magnetic body is powder and dispersed in the adhesive used for the joining, there is no major process change just by using an adhesive containing a powdered magnetic body. In addition, it can be easily manufactured without requiring a special device.

  The joint portion is basically one place, but a plurality of places may be received as necessary, and finer position detection and timing detection are possible at that time. Hereinafter, an endless belt having one joint portion will be described, but the present invention is not limited to this example.

  The endless belt of the present invention has a joining portion in which the end portions of the sheets are overlapped and joined in an endless manner, but when formed from one rectangular sheet, two joining surfaces that are overlapped with each other at both ends of the rectangular sheet. However, it is possible to join the inclined surfaces obtained by processing different surfaces of the sheet into inclined shapes so as to become thinner toward the leading ends. It is preferable because high strength and high durability can be obtained, and further, a step due to the joint is not formed, and a good image can be obtained.

In order to process the end portion in this way, for example, the end of the sheet is bonded to a fixed base that is angled with respect to the axial direction of the end mill of the milling machine, and is processed to become thinner toward the front end using the milling machine. Then, peel off from the fixed base and process the other end of the opposite surface in the same way.
At this time, the overlap width needs to be determined so that sufficient strength can be obtained.
mm to 10 mm.

  Here, the sheet used above needs to have sufficient heat resistance when an elastic layer made of silicone rubber is provided, such as a fixing belt substrate of an image forming apparatus or an intermediate transfer belt substrate. is there. Examples of such materials include polyimide, polyamideimide, polyetheretherketone (PEEK), and polyphenylene sulfide (PPS). Among them, the sheet is made of polyimide or polyamideimide because particularly high heat resistance is obtained. preferable.

  Next, an adhesive is applied to at least one of the inclined surfaces. At this time, the coating amount is set to a predetermined amount that provides sufficient adhesive strength and does not protrude. In order to apply a predetermined amount in this way, it is applied by, for example, screen printing or a dispenser.

  In the present invention, it is necessary that the magnetic body is disposed in the joint portion. Here, when a material in which a powdery magnetic body is dispersed as the adhesive is used, the flexibility of the joint portion is used. This is preferable because the endless belt can be easily manufactured without seriously damaging the belt and without requiring an extra device.

  Here, FIG. 1 schematically shows a state in which an adhesive 5 in which a powdered magnetic material is dispersed is applied to one of inclined surfaces 1 a ′ provided on different surfaces at both ends of the sheet 1 ′.

  Examples of the magnetic material dispersed and blended in the adhesive include Mn-ferrite, Ni-ferrite, Zn-filler intention, Mn-Zn-ferrite mixed with these, Ni-Zn-ferrite, and the like. The powder is preferably in a powder form so as to be uniformly dispersed in the adhesive, and the particle size is preferably 0.01 μm or more and 5 μm or less. That is, if it is less than 0.01 μm, it becomes difficult to handle, and it is difficult to degas the adsorbed gas. If it exceeds 5 μm, the dispersion system in the adhesive is deteriorated, and it is difficult to apply the adhesive thinly and uniformly. Become. A more preferable range is 0.1 μm or more and 1 μm or less.

  Further, it is preferable that the adhesive is thermosetting. Further, when an elastic layer made of silicone rubber is provided, such as a fixing belt substrate of an image forming apparatus or an intermediate transfer belt substrate, it is necessary to have sufficient heat resistance. Examples of such a material include a thermosetting polyimide adhesive, a thermosetting polyamideimide adhesive, and a bengara-containing addition polymerization silicone adhesive.

  In order to uniformly disperse the magnetic substance as described above in the adhesive, for example, a centrifugal defoamer can be used for kneading to obtain an adhesive containing the magnetic substance.

  In this way, after applying an adhesive to at least one of the inclined surfaces, the inclined surfaces are bonded to each other, and a heat treatment is performed under conditions suitable for curing the used adhesive while pressing the bonding portion as necessary. Thus, an endless belt according to the present invention is obtained.

  In some cases, the transfer belt is used as a single layer of medium resistance, but in many cases, an elastic layer made of silicone rubber (silicone resin), fluorine The intermediate transfer belt according to the present invention can be obtained by forming a release layer made of a resin thin film in this order.

  The intermediate transfer belt thus obtained includes a suspension member such as a plurality of rollers for rotatably suspending the intermediate transfer belt in the image forming apparatus, and a magnetic detection for detecting the magnetism of the magnetic material in the vicinity of the intermediate transfer belt. It is used by being set on a belt device provided with means.

  For example, as shown in FIG. 2, the intermediate transfer unit 100 according to the present invention (the intermediate transfer belt according to the present invention, a plurality of suspension members for rotatably suspending the intermediate transfer belt, and the vicinity of the intermediate transfer belt) In the belt device provided with magnetic detecting means for detecting the magnetism of the magnetic material, the intermediate transfer belt 60 is the intermediate transfer belt according to the present invention. In FIG. 2, 51K, 51M, 52C and 51Y are photosensitive drums, 52K, 52M, 52C and 52Y are transfer bias power supplies, and 60 is a superposition of toner images developed on the respective photosensitive members. Intermediate transfer belts that transfer to transfer paper to form a full color toner image on the transfer paper. Reference numerals 61 to 68 denote support rollers as a plurality of suspension members for rotatably suspending the intermediate transfer belt, and 80 denotes electrostatic adsorption. A roller, 80a is a power supply, 90 is an entrance roller blanket, 92 is a pin, 93 is a swinging blanket, 94 is a pivot shaft, 98 is an exit blanket, and 99 is magnetic Magnetic detecting means for detecting the magnetism of the body, and 100 is an intermediate transfer unit.

  In order to obtain high image quality by suppressing the misalignment of the toner images in the transfer nips of the respective colors, it is necessary to keep the endless moving speed of the intermediate transfer belt 60 as constant as possible. However, even if the driving roller of the belt is rotated at a constant speed, the endless moving speed of the belt slightly changes due to a thickness deviation in the circumferential direction of the belt. The intermediate transfer unit 100 is configured to detect the belt surface moving speed and feed back the detection result to the drive system of the drive roller in order to suppress this change as much as possible.

  Here, an enlarged view of the model near the magnetic detection means 99 is shown in FIG. The magnetism detecting means 99 in this example is composed of a magnet 99a and a gauss meter 99b, which are arranged at positions sandwiching the intermediate transfer belt 60, respectively. The intermediate transfer belt 60 is formed by laminating the endless belt 1 according to the present invention, an elastic layer 2 made of silicone resin, and a release layer 3 made of fluorine resin. The joint 6 of the intermediate transfer belt 60 of the endless belt 1 according to the present invention is bonded by an adhesive in which magnetic powder is dispersed.

  When such an intermediate transfer belt 60 is rotationally driven and reaches the vicinity of the magnetic detection means 99, the output of the gauss meter increases, and as a result, the position of the joint 6 of the intermediate transfer belt 60 can be known. The rotational speed can be determined by measuring the time from when the intermediate transfer belt 60 is further rotated to reach the vicinity of the magnetic detection means 99 again. By connecting a microcomputer to the gauss meter of the magnetic detection means 99, the position of the belt can be detected (position estimation), and the synchronization timing can be taken. That is, when the microcomputer performs servo control, for example, on the actuator that drives the rotation of the intermediate transfer belt 60, the synchronization timing of image formation can be matched and a color image without deviation can be obtained.

  At this time, the microcomputer detects the rotation position of the belt based on the data from the magnetic detection means and estimates the subsequent position change, and the synchronization timing of image formation from the position change of the intermediate transfer belt. Therefore, it functions as a belt rotation control means for controlling the rotation of the intermediate transfer belt.

  In addition, by providing a plurality of magnetic detection means 99 in different places and connecting them to a microcomputer, the synchronization timing of image formation can be adjusted more accurately and finely.

It is model sectional drawing which shows the manufacturing method of the endless belt of this invention. FIG. 3 is a model diagram illustrating an intermediate transfer unit according to the present invention. FIG. 6 is an enlarged model view of the vicinity of magnetic detection means 99 of the intermediate transfer unit.

Explanation of symbols

1 'sheet 1a' inclined surface 1 endless belt (belt base material) according to the present invention
DESCRIPTION OF SYMBOLS 2 Elastic layer 3 Release layer 5 Adhesive with which magnetic body was mix | blended 6 Junction part 60 Intermediate transfer belt concerning this invention

Claims (5)

In an endless belt having a joined portion joined endlessly by overlapping the end portions of the sheet,
An endless belt, wherein a magnetic body is disposed at the joint.   The endless belt according to claim 1, wherein the magnetic body is powder and is dispersed in an adhesive used for the joining.   An intermediate transfer belt comprising the endless belt according to claim 1, a plurality of suspension members for rotatably suspending the intermediate transfer belt, and magnetism of the magnetic material in the vicinity of the intermediate transfer belt. A belt device comprising magnetic detecting means for detecting.   An intermediate transfer unit comprising the belt device according to claim 3.   An image forming apparatus comprising the intermediate transfer device according to claim 4.

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