JP2014109654A - Member for rotation detection, and fixation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member for rotation detection and fixation device that can reduce the bending stress occurring in a fixing belt by a simple method without applying a special processing and burden to the fixing belt, and can transmit a stable rotation driving of the fixing belt to rotation detecting means for a long time.SOLUTION: The member 10 for rotation detection includes: a cylindrical main body 11 for covering the outer peripheral surface of an end 1a of a fixing belt 1 of a fixation device; an elastic member 12 that is disposed on the inner peripheral surface of the main body 11 and comes into contact with the outer peripheral surface of the fixing belt 1 inserted into the main body 11; and a rotation transmission surface 13 that is disposed on the outer peripheral surface of the main body 11 and driven-rotates a driven-rotation member of detecting means for detecting the rotation of the fixing belt 1.

Description

  The present invention relates to a fixing belt rotation detecting member and a fixing device, and can detect rotation of a fixing belt that is driven only by being placed on an axial end portion of the fixing belt.

  Image forming apparatuses such as copying machines, facsimile machines, and laser beam printers include a fixing device that fixes unfixed toner. In such a fixing device, a predetermined nip is formed by an endless fixing belt and a pressure roll disposed opposite to the fixing belt, and the image is transferred onto the sheet by heat and pressure at the nip portion. There are some which melt and penetrate toner and fix an image. As a heat source, there is one that heats the fixing belt using an IH (induction heating) heater, a halogen heater, or the like. In particular, when an IH heater is used, since the heating efficiency is high, there is a problem that if the fixing belt abnormally rotates, the fixing belt is locally excessively heated to cause deterioration or thermal destruction of the fixing belt. In order to prevent such an excessive temperature rise, a fixing device that detects the rotation of the fixing belt by an optical sensor and controls a heating source has been proposed (for example, Patent Document 1).

  However, the fixing device described in Patent Document 1 is a countermeasure against an abnormality, and cannot stably detect the rotation driving of the fixing belt over a long period of time.

  Also, a fixing jig is attached to the end of the fixing belt, and the optical sensor cam is rotationally driven through the jig, and the rotation position of the optical sensor cam is detected, thereby fixing the fixing belt. There is a fixing device that detects the rotation of the belt. However, in such a rotation detection method, not only is it time-consuming to attach a jig to the inner surface of the fixing belt, but also a cylindrical jig is fitted and bonded to the end portion, so that the part that forms the nip portion However, as shown in FIG. 5, there is a problem that bending stress is concentrated between the fixing belt and the portion pressed by the end portion of the pressure roll, and this causes the fixing belt to be broken.

  On the other hand, there is a method of marking the outer peripheral surface of the fixing belt with a laser or the like and measuring the cycle, but this increases the number of processing steps (for example, Patent Document 2).

Japanese Patent Laying-Open No. 2005-070321 JP 2009-237188 A

  In view of such circumstances, the present invention can reduce the bending stress generated in the fixing belt by a simple method without giving special processing and a burden to the fixing belt, and can detect the rotation of the fixing belt stably for a long time. An object of the present invention is to provide a rotation detecting member and a fixing device which can be transmitted to the means.

  An aspect of the present invention that solves the above-described problems includes a cylindrical main body that covers an outer peripheral surface of an end portion of a fixing belt of a fixing device, and an inner peripheral surface of the main body that is inserted into the main body. An elastic member that contacts the outer peripheral surface of the fixing belt; and a rotation transmission surface that is provided on the outer peripheral surface of the main body and that rotates the driven rotation member of the rotation detecting unit that detects the rotation of the fixing belt. The rotation detecting member is characterized.

  According to this invention, since the elastic member provided on the inner peripheral surface of the main body is only in contact with the outer peripheral surface of the fixing belt end, the fixing belt even when the fixing belt is bent inward at the nip portion. No bending stress is generated in the case. As a result, it is possible to transmit the rotation driving of the fixing belt to the rotation detecting means by using the frictional force generated between the fixing belt and the elastic member without giving special processing and load to the fixing belt, Damage can be prevented.

  Here, the elastic member is preferably an O-ring.

  According to this invention, the rotation driving of the fixing belt can be simply transmitted to the rotation detecting means via the O-ring.

  In another aspect of the present invention, a fixing belt including the rotation detection member, a driven rotation member provided in contact with the rotation transmission surface and driven to rotate, and the rotation detection unit rotating together with the driven rotation member, A fixing device comprising:

  According to this invention, the driven rotation member that can accurately transmit the rotation driving of the fixing belt to the rotation detection unit and the rotation detection unit that rotates together with the driven rotation member are provided, and the driven rotation member is brought into contact with the outside of the fixing belt. Therefore, even when the fixing belt is bent inward at the nip portion, no bending stress is generated, and deterioration and damage of the fixing belt can be prevented, and a highly reliable fixing device can be realized.

  According to the rotation detecting member of the present invention, the rotation driving of the fixing belt is used as the rotation detecting means by using the frictional force generated between the fixing belt and the elastic member by a simple method without giving special processing and a burden to the fixing belt. Further, the fixing belt can be prevented from being deteriorated or damaged.

  According to the fixing device of the present invention, deterioration and damage of the fixing belt can be prevented, and the fixing belt can be stably rotated over a long period of time. Further, failure of the fixing device can be reduced, and reliability can be improved.

FIG. 3 is an explanatory view showing a state in which the rotation detection member according to the present embodiment is attached to the fixing belt, and a sectional view of the attached state. FIG. 3 is a perspective view of a fixing mechanism of a fixing device including a rotation detection member according to the embodiment. FIG. 3 is a cross-sectional view taken along line II of the fixing mechanism of the fixing device in FIG. 2. FIG. 3 is a cross-sectional view taken along the line II-II of the fixing mechanism when the fixing device in FIG. 2 is driven. Sectional drawing of the fixing mechanism at the time of the drive of the fixing device provided with the member for conventional rotation detection.

  Hereinafter, the present invention will be described in detail based on embodiments.

(Embodiment 1)
The rotation detection member according to the present invention is used by covering at least one of the axial ends of the fixing belt of the fixing device.

  FIG. 1 is an explanatory view showing a state where the rotation detecting member according to the present embodiment is attached to the fixing belt, and a sectional view of the attached state.

  The rotation detection member 10 includes a cylindrical main body 11 into which the end 1a of the fixing belt 1 is inserted, and an elastic member 12 made of, for example, an O-ring provided on the inner peripheral surface of the main body 11. A part of the outer peripheral surface of the main body 11 is composed of a rotation transmission surface 13 that rotates the driven rotation member 31 (see FIG. 2) of the rotation detecting means 30 that detects the rotation of the fixing belt 1. Here, the rotation transmission between the rotation transmission surface 13 and the driven rotation member 31 may be performed by close contact between the outer peripheral surfaces. However, in order to transmit the rotation reliably, it is preferable that the rotation transmission surface 13 and the driven rotation member 31 are engaged with each other. In the present embodiment, the rotation transmission surface 13 is simplified in illustration, but a plurality of teeth 13 a are provided, and the outer peripheral surface of the driven rotation member 31 is provided with teeth 31 a that mesh with the teeth 13 a of the rotation transmission surface 13. ing.

  One end of the main body 11 into which the fixing belt 1 is inserted has an inner diameter slightly larger than the outer diameter of the fixing belt 1. A recess 14 for fitting the elastic member 12 is provided on the inner peripheral surface of the main body 11 along the inner periphery. The elastic member 12 before the fixing belt 1 is inserted into the main body 11 has an inner diameter that is slightly smaller than the outer diameter of the fixing belt 1 and an outer diameter that is substantially the same as the inner diameter of the concave portion 14. As a result, it is held in a state in which a part thereof protrudes inward. When the fixing belt 1 is inserted into the main body 11, the elastic member 12 contacts the fixing belt 1 by pressing the outer peripheral surface of the end 1 a of the fixing belt 1 with an elastic force.

  As described above, the elastic member 12 is fitted in the recess 14, and the inner diameter thereof is in contact with the fixing belt 1, and the rotational driving force of the fixing belt 1 is applied to the rotation detection member 10 via the elastic member 12. It is set to ensure transmission. As a result, the rotation detecting member 10 rotates together with the fixing belt 1, and there is no slip between the fixing belt 1 and the elastic member 12.

  A support portion 15 that closes the opening of the end surface is provided on the other end side of the rotation detection member 10, and a through hole 16 is provided in the support portion 15. A bearing 17 is provided in the through hole 16, and a support shaft 22 a at an end of the support member 22 that supports the pressing member 21 provided inside the fixing belt 1 is fitted into a shaft support member (not shown) of the bearing 17. It is like that. As a result, the rotation detection member 10 is fitted to and supported by the end 1a of the fixing belt 1 and is freely rotatable with respect to the support shaft 22a. The through-hole 16 may be a through-hole having a size that does not interfere with the support shaft 22 a, and may be supported as long as the end of the support shaft 22 a penetrates the through-hole 16. In this case, no bearing is required.

  Further, as described above, the rotation transmission surface 13 of the rotation detection member 10 may be a gear shape or a surface that transmits rotation by friction, for example, a surface made of a rubber member having a large friction coefficient. Further, the rotation transmission with the driven rotation member 31 may be performed directly as described above, but may be performed indirectly via a belt or a timing belt.

  The rotation detection member 10 described above is made of, for example, metal or hard resin.

  Examples of the elastic member 12 include rubber members such as an O-ring and packing. In this embodiment, an O-ring is used. In addition, there is no restriction | limiting in particular about the number of elastic members.

  Next, the fixing mechanism of the fixing device will be described. FIG. 2 is a perspective view of the fixing mechanism of the fixing device including the rotation detecting member according to the present embodiment, and FIG. 3 is a cross-sectional view taken along line II of the fixing mechanism of the fixing device in FIG.

  The fixing mechanism 2 of the fixing device includes a fixing belt 1 in which a rotation detection member 10 is inserted at an end thereof, and a pressure roll 25 that is provided at a position facing the fixing belt 1 and rotates the belt while pressing the fixing belt 1. And a pressing member 21 that is provided inside the fixing belt 1 and presses the pressure roll 25 from the inside, and a support member 22 that supports the pressing member 21. Further, a rotation detecting means 30 for the fixing belt 1 provided above the fixing belt 1 and a heating means 40 for heating the fixing belt 1 to a predetermined temperature are provided.

  The fixing belt 1 may be any belt that can form a predetermined nip portion by pressure contact with the opposing pressure roll 25, and preferably uses a resin belt such as polyimide or an electroformed belt. In particular, the resin belt is liable to break due to stress concentration, so it is preferable to apply an electroformed belt.

  The pressure roll 25 includes a core body 26 made of metal or the like, and an elastic layer 27 made of rubber or the like formed around the core body 26. Further, a release layer made of a fluororesin or the like may be provided around the elastic layer 27.

  The pressing member 21 is made of, for example, an elastic body such as rubber, resin, metal, or the like. When the fixing belt 1 is driven, the pressing member 21 presses the fixing belt 1 against the pressure roll 25 while sliding with the inner peripheral surface of the fixing belt 1, and deforms the elastic layer 27 of the pressure roll 25. A predetermined nip portion is formed between the pressure roll 25 and the fixing belt 1.

  The support member 22 supports the pressing member 21 so as not to rotate and move from the back side. When the fixing belt 1 is rotated by the rotation of the pressure roll 25, the pressing member 21 is fixed to the fixing belt 1. It is held in a state where it slides on the inner peripheral surface.

  The rotation detection means 30 is for detecting the rotation of the fixing belt 1. In this embodiment, an optical sensor is used. The rotation detection means 30 supports a driven rotation member 31 that engages with the rotation transmission surface 13 of the rotation detection member 10 in a fitted state, and a rotation shaft 32 that can rotate together with the driven rotation member 31. An optical sensor cam 33 that is fixed to the end and has a plurality of wings 33 a and an optical sensor 34 that detects the rotation period of the optical sensor cam 33 are provided.

  The driven rotating member 31 meshes with the teeth 13 a of the rotation transmitting surface 13 of the rotation detecting member 10 that rotates following the rotation of the fixing belt 1 via the teeth 31 a of the driven rotating member 31. It rotates with the rotating shaft 32 following the rotation. Thereby, the cam 33 for optical sensors also rotates. The optical sensor 34 detects the rotation period of the optical sensor cam 33. That is, the rotation cycle of the photosensor cam 33 can be grasped from the detection signal of the photosensor 34, and the rotation cycle of the fixing belt 1 can be grasped by converting this to the rotation cycle of the fixing belt 1. Such detection of the rotation period of the fixing belt 1 is performed by a control device 35 that receives a detection signal from the optical sensor 34. For example, the control device 35 can grasp the rotation failure of the fixing belt 1 from the change in the rotation cycle of the fixing belt 1, thereby preventing image defects such as fixing failure.

  The heating unit 40 may be anything that can heat the fixing belt 1. For example, if the fixing belt 1 is compatible, an IH (electromagnetic induction) heater using an excitation coil can be used. Others include halogen heaters, heating wire heaters, ceramic heaters, and the like. In this embodiment, an IH heater is used.

  In the fixing mechanism 2 of such a fixing device, the recording material 29 carrying the unfixed toner 28 is nipped and conveyed between the fixing belt 1 and the pressure roll 25, and the unfixed toner is heated and pressed at the nip portion. 28 is fixed on the recording material 29.

  Next, the rotation detection member 10 of the present invention will be further described with reference to FIGS. 4 and 5 while comparing with a conventional rotation detection member. FIG. 4 is a sectional view taken along line II-II of the fixing mechanism when the fixing device in FIG. 2 is driven. FIG. 5 shows a cross-sectional view of the fixing mechanism during driving of a fixing device having a conventional rotation detecting member.

  FIG. 4 is a cross-sectional view showing a state in which the rotation detection member of the present invention is attached to the fixing belt. The rotation detecting member 10 is mounted so as to cover the outer peripheral surface of the end portion 1 a of the fixing belt 1, and the end portion 1 a of the fixing belt 1 is in contact with an elastic member 12 provided on the inner peripheral surface of the main body portion 11. There is only. Further, the rotation transmission surface 13 of the rotation detection member 10 and the driven rotation member 31 of the rotation detection means 30 are arranged in a state of being engaged with each other.

  When the pressure roll 25 is pressed at a position facing the pressing member 21 provided on the inner periphery of the fixing belt 1, the fixing belt 1 extends in the axial direction at the nip portion on the lower side of the drawing. The bending stress tends to concentrate on the axially central portion pressed by (dotted line circle portion in FIG. 4). However, since the end 1a of the fixing belt 1 and the elastic member 12 of the rotation detecting member 10 are only in contact with each other, the end 1a of the fixing belt 1 is separated from the elastic member 12 at the end of the nip portion.

  As described above, when the rotation detecting member 10 of the present invention is used, the rotation driven by the fixing belt 1 is maintained, and on the other hand, no large bending stress is generated in the end 1a of the fixing belt 1 in the vicinity of the nip portion. . That is, as shown in the figure, at the nip portion, the end 1a of the fixing belt 1 is separated from the elastic member 12, so that no bending stress is generated in the axial direction, and between the nip portion and its peripheral portion. The bending stress in the circumferential direction does not become large. As a result, the durability of the fixing belt can be improved, and stable rotation driving of the fixing belt can be continuously transmitted to the rotation detecting means 30.

  On the other hand, as shown in FIG. 5, the conventional rotation detection member 100 is fitted inside the end of the fixing belt 101, and the fitted portion is fixed to the fixing belt 101 with an adhesive 103. It was. Therefore, the fixing belt 101 is greatly curved at the nip portion formed by the pressure contact with the opposing pressure roll 25, and a large bending stress is generated near the boundary between the fixing belt 101 and the end portion of the pressure roll 102 in the nip portion. Will be concentrated (dotted circle portion in FIG. 5). As a result, the fixing belt 101 is rotationally driven in a largely curved state, and is easily damaged at the stress concentration portion of the fixing belt. If the fixing belt is damaged, the rotation detecting means stops the operation of the heating means (IH heater) and the copying machine is stopped, which has a great influence.

  From the above, according to the rotation detecting member of the present invention, even when the fixing belt is bent inward at the nip portion, no great bending stress is generated on the fixing belt, so that the durability of the fixing belt is improved. Thus, the rotation driving of the fixing belt that is stable over a long period of time can be continuously transmitted to the rotation detecting means.

  Further, the rotation detecting member of the present invention can be mounted by a very simple method of simply covering the fixing belt without giving any special processing and load to the fixing belt.

  According to the fixing device of the present invention having such a rotation detecting member, not only the fixing belt can be prevented from being deteriorated and damaged, but also the fixing belt can be stably rotated over a long period of time. As a result, a failure can be reduced and a highly reliable fixing device can be realized.

(Other embodiments)
Although one embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above-described embodiment. The rotation detection member and the fixing device according to the present invention can be mounted on various image forming apparatuses such as a copying machine, a facsimile machine, a laser beam printer, another printer, and a multifunction machine thereof.

DESCRIPTION OF SYMBOLS 1 Fixing belt 2 Fixing mechanism 10 of fixing device Rotation detection member 11 Main body part 12 Elastic member 13 Rotation transmitting surface 14 Recess 15 Support part 16 Through hole 17 Bearing 21 Press member 22 Support member 25 Pressure roll 26 Core 27 Elastic layer 28 Unfixed toner 29 Recording material 30 Rotation detection means 31 Driven rotation member 32 Rotating shaft 33 Optical sensor cam 34 Optical sensor 40 Heating means 100 Rotation detection member 101 Fixing belt 102 Pressure roll 103 Adhesive

Claims (3)

A cylindrical main body covering the outer peripheral surface of the end of the fixing belt of the fixing device;
An elastic member that is provided on an inner peripheral surface of the main body and is in contact with an outer peripheral surface of the fixing belt inserted into the main body;
A rotation detection member, comprising: a rotation transmission surface provided on an outer peripheral surface of the main body portion and driven to rotate a driven rotation member of rotation detection means for detecting rotation of the fixing belt. In the rotation detecting member according to claim 1,
The rotation detecting member, wherein the elastic member is an O-ring.   A fixing belt comprising the rotation detection member according to claim 1, a driven rotation member provided in contact with the rotation transmission surface and driven to rotate, and the rotation detection means rotating together with the driven rotation member. A fixing device comprising the fixing device.

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