JP2013134422A - Image heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image heater configured such that while foreign mater, such as scraped powder sticking to the internal circumferential surface of a rotatable flexible member, is removed, a lubricant for smoothing the rotation of the rotatable flexible member does not have to be removed but can be left.SOLUTION: A cleaning member by which foreign matter sticking to the internal circumferential surface of the flexible member as a result of sliding operation is cleaned off is provided downstream of a nip part and in a place within a sliding surface or out of the surface adjacent to the sliding surface.

Description

  The present invention relates to an image heating apparatus used in an image forming apparatus employing an image forming process such as an electrophotographic system or an electrostatic recording system, such as a copying machine or an LBP. As an image heating device, a fixing device that heats and fixes an unfixed toner image formed on a recording material as a fixed image, or a glossiness increasing device that increases the glossiness of an image by heating the image fixed on the recording material Etc.

  Conventionally, a heat roller system has been used as a fixing device provided in an image forming apparatus that employs an electrophotographic system, an electrostatic recording system, or the like. However, a heat roller type fixing device heats a heat roller having a large heat capacity, and therefore requires a great amount of power and time. On the other hand, in order to meet the recent demand for energy saving and quick start, a belt-type fixing device using a fixing belt as shown in Patent Document 1 has been proposed.

  A conventional example will be described with reference to FIG. FIG. 4 is a cross-sectional perspective view of a main part of the belt-type fixing device. In the belt-type fixing device, a fixing belt 1 (the fixing belt 1 is shown by cutting away the front side of the drawing to illustrate the internal structure) and a pressure unit 2 are arranged in pressure contact. Inside the fixing belt, a guide part 4 as a sliding member for causing the fixing belt to closely follow the rotation drive of the pressure unit 2, and a nip forming part (not shown) for generating a contact part and a nip part of the pressure unit. Further, a heat source 6 that generates radiant heat for heating the inner surface of the fixing belt is disposed.

  The nip forming portion is supported by the guide portion 4 in order to form a uniform nip portion with the pressure unit, and the guide portion 4 as a sliding member presses uniformly in the longitudinal direction, so that the support member 5 is supported. Is supported by pressure. Further, one or more openings 5 a are formed in the support member 5 so that radiant heat is directly transmitted from the exposed heat source 6 to the fixing belt 1. As the heat source 6 as a radiant heating source of the fixing device, a halogen lamp, a heat ray, a ceramic heater, or the like is used.

JP 2009-104114 A

  However, in the fixing device using the exposed radiant heat source, the following problems occur. That is, when the fixing belt slides on a member in the fixing unit, foreign matter such as shavings is generated, the generated foreign matter adheres to the fixing belt, and the foreign matter attached to the fixing belt is caused by factors such as power. There is a possibility of falling from. Here, the foreign matter includes a fixing belt, a sliding member, a shaving powder of the nip forming member, and the like generated when the fixing belt and the sliding member or the nip forming member rub against each other.

  Because radiant heat is directly applied to the fixing belt from the heat source, the heat source has a configuration exposed to the fixing belt, there is no means to protect the heat source from falling foreign matter, and if foreign matter adheres to the surface of the heat source, uniform heating may not be possible, The part to which foreign matter is attached becomes abnormally hot and the heat source fails.

  That is, when a halogen lamp is used as a heat source, for example, a high resistance body (for example, molybdenum wire) is encapsulated in a transparent glass, and when the current flows through the high resistance body, the high resistance body generates heat and emits light. . The light becomes radiant heat and heats the heating belt. Therefore, if foreign matter such as shavings adheres to the glass portion of the halogen lamp, the radiant heat is blocked and uniform heating cannot be performed. In addition, the part where the foreign matter is attached becomes abnormally high in temperature, and the expansion / contraction rate changes due to a temperature difference from the surroundings, resulting in damage to the halogen lamp. For this reason, foreign matter should not be attached to the surface of the halogen lamp, and it is necessary to remove the foreign matter attached to the inner surface of the fixing belt.

  On the other hand, in recent years, it has become a major goal to increase the speed and durability of machines, and in order to achieve this, measures are taken to increase the rotation speed of the fixing belt. When these measures are implemented, the load caused by sliding between the fixing belt and the sliding member or nip forming member increases, and more foreign matter such as shavings is generated in the fixing belt. The possibility that foreign matters such as powder adhere will increase. In addition, the miniaturization of the machine has been promoted, and in the miniaturized heating unit, the distance between the fixing belt and the heat source becomes closer, so that the possibility that foreign matters such as shavings adhere to the surface of the halogen lamp increases.

  In such a fixing device, in order to reduce the load caused by sliding between the fixing belt and the sliding surface, a lubricant is provided on the inner peripheral surface of the fixing belt, but foreign matters are removed, but the lubricant is not removed. It is more preferable if a state where the lubricant always exists and the lubricant is circulated is maintained.

  A first object of the present invention is to provide an image heating apparatus capable of removing foreign matters such as shavings adhering to the inner peripheral surface of a rotatable flexible member.

  The second object of the present invention is to provide an image heating apparatus capable of removing foreign matter such as shavings adhering to the inner peripheral surface of a rotatable flexible member while not removing the lubricant. There is.

  In order to achieve the above object, a typical configuration of an image heating apparatus according to the present invention includes a rotatable flexible member, and a position inside the flexible member that is spaced apart from the flexible member. A radiation heating source, a sliding member having a sliding surface facing the inner peripheral surface of the flexible member, and a pressure member that forms a nip portion with the sliding member via the flexible member; An image heating apparatus that passes the recording material through the nip portion and heats the recording material, and is located on the downstream side of the nip portion and in the in-plane position of the sliding surface or adjacent to the sliding surface. A cleaning member that cleans foreign matter generated by sliding and adhering to the inner peripheral surface of the flexible member is provided at an out-of-plane position.

  In addition, another representative configuration of the image heating apparatus according to the present invention includes a rotatable flexible member, and radiant heating disposed in a position separated from the flexible member inside the flexible member. A sliding member having a source, a sliding surface facing the inner peripheral surface of the flexible member, and a lubricant applied to the sliding surface; and the sliding member via the flexible member; A pressure member that forms a nip portion, and an image heating device that passes a recording material through the nip portion and heats the recording material, and is located on an in-plane position of the sliding surface or downstream of the nip portion. A cleaning member that leaves the lubricant in a position outside the sliding surface adjacent to the sliding surface and that cleans foreign matter generated by sliding and adhering to the inner peripheral surface of the flexible member Is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the image heating apparatus which can remove foreign materials, such as a shaving powder adhering to the internal peripheral surface of a rotatable flexible member, can be provided.

1 is a cross-sectional view of a fixing device as an image heating device according to a first embodiment of the present invention. 1 is a schematic configuration diagram of an image forming apparatus equipped with an image heating apparatus according to an embodiment. FIG. 6 is a cross-sectional view of a fixing device as an image heating device according to a second embodiment of the present invention. It is a schematic perspective view of a fixing device in a conventional example.

<< First Embodiment >>
(Image forming device)
FIG. 2 shows an overall configuration diagram of an example of an image forming apparatus equipped with an image heating apparatus according to an embodiment of the present invention. This image forming apparatus is a laser beam printer using an electrophotographic system. The image forming apparatus includes a drum-type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) 10 as an image carrier, and a charging member 11, a developing device 13, and a cleaning device 19 are installed around the photosensitive drum 10. Has been. An exposure device 12 is installed as a means for creating a latent image on the photosensitive drum.

  The photosensitive drum 10 is an OPC photosensitive member having a photoconductive layer on an aluminum drum base, and is rotated at a predetermined process speed in the direction of an arrow C by a driving device (not shown). The charging member 11 uniformly charges the surface of the photosensitive drum 10 to a predetermined negative potential with a charging bias applied from a charging bias power source (not shown). The developing device 13 develops a toner image by attaching toner to the electrostatic latent image formed on the photosensitive drum 10. As a developing method by the developing device 13, for example, toner particles mixed with a magnetic carrier are used as a developing material, conveyed by magnetic force, and developed in contact with the photosensitive drum 10.

  The transfer roller 16 serving as a transfer unit is made of an elastic member, abuts against the photosensitive drum 10, and a high voltage is applied when transferring. The cleaning device 19 removes and collects the transfer residual toner remaining on the surface of the photosensitive drum 10.

  In the exposure device 12, laser light modulated in accordance with the time-series electric digital pixel signal of the image information is output from a laser output unit (not shown) and exposed via a polygon mirror (not shown) that rotates at high speed. The surface of the drum 10 is exposed. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum charged by the charging member 11.

  The paper feed roller 14 has a D shape so as not to contact the recording material P so as not to hinder the conveyance after the recording material P is fed and then delivered to the registration roller pair 15.

(Operation of image forming apparatus)
Next, the operation of the image forming apparatus will be described. The printer shown in this embodiment receives image information from an image information providing device (not shown) such as a host computer provided outside the printer main body. Then, the printer performs a series of image forming processes in which an image corresponding to the received image information is formed and recorded on a sheet-like recording material P in accordance with a known electrophotographic system.

  When the printer receives the print signal, rotation of the photosensitive drum 10 as the image carrier is started. The photosensitive drum 10 is driven to rotate clockwise at a specified peripheral speed. At the same time, the surface of the photosensitive drum 10 is charged to a specified potential by the charging member 11 as a primary charging device to which a specified bias is applied. In the present embodiment, a so-called reversal development method in which the exposed portion on the photosensitive drum 10 is reversely developed is used, and the charging potential is negative.

  Next, the charged portion of the surface of the photosensitive drum 10 is scanned and exposed by the exposure device 12 according to the image information from the image information providing device. In the exposed area, the potential of the surface of the photosensitive drum 10 is canceled, the surface potential is relatively positive with respect to the surroundings, and an electrostatic latent image corresponding to image information is formed on the surface of the photosensitive drum 10. The negatively charged developer (toner) is developed by the developing device 13 in an exposure region having a potential on the positive electrode side relative to the surroundings, and visualized as a developer image on the surface of the photosensitive drum 10. The

  On the other hand, the recording material P is separated and fed from the sheet feeding cassette by the sheet feeding roller 14 driven at a predetermined timing. The recording material P fed from the paper feed cassette is fed to a transfer nip N formed between the photosensitive drum 10 and the transfer roller 16 by the registration roller pair 15 at a predetermined control timing. Then, the toner images on the photosensitive drum 10 are sequentially transferred onto the recording material P in the process of being nipped and conveyed through the transfer nip portion N.

  The recording material P that has been subjected to the transfer process is subjected to a heat fixing process of the toner image by the fixing device 17, and then passes through the paper discharge roller pair 18 and is discharged out of the printer main body. The transfer residual toner remaining on the photosensitive drum is cleaned by the cleaning device 19 to complete a series of image forming processes.

(Image heating device)
1) Overall Configuration Now, characteristic portions of the present invention will be described with reference to FIG. FIG. 1 is an enlarged schematic cross-sectional view of a main part of a belt-type fixing device. In FIG. 1, a pressure unit 2 as a pressure member that is rotatable in the direction of arrow A, and a state in which the pressure unit 2 is circumscribed. The heating unit 10 that rotates in the direction of arrow B is provided. The fixing belt 1 is heated by a heat source 6 as a radiant heating source provided at a position separated from the fixing belt 1, and a nip portion N is formed at a contact portion between the pressure unit 2 and the heating unit 10, so as to serve as a recording material. Is passed through the nip N and heated.

2) Pressure unit The pressure unit 2 includes a pressure member that forms a nip portion N and a sliding member described later via the fixing belt 1. The pressure member is a long cylindrical roller member that presses the recording material P against the heating unit 10 and is configured by providing an elastic layer and a release layer on the core material. An iron cored bar is used as the core, a foamed silicone rubber layer is used as the elastic layer, and a fluororesin tube is used as the release layer.

3) Heating unit The heating unit 10 includes a fixing belt 1 that is a flexible member that is rotatable by receiving a rotational force from the pressure unit 2. The fixing belt 1 is configured by providing a surface layer as a base layer on at least a heat-resistant resin such as polyimide, polyamideimide, PEEK, or a metal base material such as nickel or SUS.

  The heat-resistant resin as the base layer has a thickness of 30 to 200 μm, and the surface layer is coated with a fluororesin. Moreover, the thickness of the metal substrate is 30 μm to 100 μm, the surface layer is a silicone rubber layer having a thickness of 100 to 1000 μm as an elastic layer, and the release layer is covered with a fluororesin tube. A heat-resistant black paint is applied to the inner peripheral surface of the fixing belt 1 to efficiently absorb heat from a heat source.

  In the present embodiment, the configuration in which the fixing belt 1 operates by driving the pressure unit 2 is illustrated. However, a separate driving device for driving the fixing belt 1 may be provided.

4) Sliding member In the present embodiment, the sliding member provided with a sliding surface facing the inner peripheral surface of the fixing belt 1 and coated with a lubricant includes the nip forming portion 3, the upstream side of the nip forming portion 3, and And a curved guide portion 4 provided on the downstream side for guiding the inner peripheral surface of the fixing belt 1. The lubricant is applied to the inner peripheral surface of the fixing belt 1 for smooth running of the fixing belt 1, liquefies at a high temperature, adheres to the inner peripheral surface of the fixing belt 1, and rotates together with the fixing belt 1. The nip forming part 3 is formed of a heat conductive first material so that the radiant heat H is directly transmitted from the heat source 6 through the opening of the guide part 4, while the guide part 4 is a heat insulating second material. The material is formed.

  That is, the nip forming member 3 is formed from a metal such as aluminum or copper having excellent thermal conductivity or an alloy thereof. Further, the nip forming member 3 can also be configured with an uneven shape or the like that changes the pressure distribution in the fixing nip N. Further, the plate material of the nip forming member 3 may be provided with a resin coating such as a fluororesin or a glass coating.

  On the other hand, the guide portion 4 is formed of a heat-resistant resin such as a liquid crystal polymer, a phenol resin, PPS, or PEEK having heat insulation, high heat resistance, and rigidity. The guide portion 4 is formed so that the surface in contact with the fixing belt 1 is a curved surface, so that the fixing belt 1 can run smoothly.

5) Support member The support member 5 is a structure having a predetermined rigidity so as to pressurize the guide portion 4, and is formed of a metal having excellent strength such as stainless steel or spring steel. The role of the supporting member 5 is to support the nip forming portion 3 supported by the guide portion 4 pressed by the supporting member 5 on both sides of the side surface, and simultaneously pressurize in the direction corresponding to the pressing unit 2 to A uniform fixing nip N is formed along the direction.

  A constant pressing force necessary for fixing the developer image transferred to the recording material P is applied between the nip forming unit 3, the guiding unit 4 and the pressing unit 2 by the support member 5. Acts uniformly in the rotation axis direction (longitudinal direction) of the pressure unit 2. The support member 5 is formed with one or more openings 5 a so that the radiant heat H is directly transmitted from the heat source 6 to the fixing belt 1. The heat transfer from the nip forming member 3 to the support member 5 during the initial temperature increase is suppressed by the heat-insulating guide portion 4, thereby preventing the temperature increase time from increasing.

6) Heat source The heat source 6 is provided so as to be positioned at a substantially central portion inside the fixing belt 1. That is, the heat source 6 is provided at a position where the radiant heat H is directly transmitted to at least a part of the inner surface of the fixing belt 1 and at least a part of the nip forming member 3. The heat source 6 generates heat by applying power from the outside, and heats the nip forming member 3 through the opening of the guide portion 4 and simultaneously heats the fixing belt 1 through the opening 5 a of the support member 5. As such a heat source 6, a halogen lamp, a heat wire, a ceramic heater, or the like can be used, and a cylindrical halogen lamp is preferably used.

  Further, the fixing device of the present embodiment includes a temperature sensor provided in at least one portion of the fixing belt 1, the nip forming portion 3, the guide portion 4, and the support member 5 in order to detect the temperature of the device. In order to maintain a predetermined fixing temperature for smooth fixing based on the temperatures detected by these temperature sensors, a temperature control unit for controlling the amount of heat generated by the heat source 6 can be provided.

  Further, since the heat fixing process is performed from the fixing belt 1 to the entire recording material, the total size in the longitudinal direction of the opening 5a is formed to be approximately the same as the size of paper that can be passed through the fixing device.

7) Cleaning member The guide member 4 has a depth of about 3 to 5 mm at a position in the plane of sliding with the fixing belt 1 and downstream of the nip portion N in the rotation direction of the fixing belt 1. A groove 9 is formed. The cleaning member 7 is attached to the groove 9 via the adhesive layer 8, and is disposed so that one surface of the cleaning member 7 protrudes from the sliding surface between the fixing belt 1 and the guide portion 4. One surface of the cleaning member 7 is rubbed with the inner peripheral surface of the fixing belt 1, and the surface of the cleaning member 7 facing the inner peripheral surface of the fixing belt 1 is bonded to the adhesive layer 8. As the adhesive layer 8, a double-sided tape or adhesive having high heat resistance can be used.

  The cleaning member 7 scrapes off the foreign matter in advance so that the foreign matter in the portion where the fixing belt 1 is exposed to the halogen lamp does not fall on the halogen lamp as the fixing belt rotates. Therefore, it is desirable that the size of the cleaning member 7 in the longitudinal direction covers the entire portion corresponding to the longitudinal direction of the opening 5 a of the support member 5. Further, the width of the cleaning member 7 is configured not to be larger than the width of the groove 9 and is formed of an elastic body in order to ensure adhesion with the fixing belt 1 and at the same time to give a stable pressure to the fixing belt. The

  The cleaning member 7 is preferably formed of a foamed rubber material in order to leave the lubricant on the inner surface of the fixing belt 1. That is, the unevenness of the cleaning member 7 formed of the foamed rubber material is fine enough to scrape off the shavings generated by the rubbing of the fixing belt 1 with the sliding member 4 or the nip forming member 3 and is liquid. It becomes about 10 μm to 100 μm, which is sufficiently coarse to allow the lubricated lubricant to pass through. Further, since the cleaning member 7 needs to be excellent in heat resistance, it can be formed of, for example, fluororubber or silicon.

(Effect of this embodiment)
As described above, according to the present embodiment, a groove is provided on the sliding surface between the sliding member and the fixing belt, and the cleaning member formed of an elastic body is disposed in the groove, so that a foreign matter is formed on the surface of the halogen lamp. It becomes difficult to adhere, and it becomes possible to prevent the failure of the halogen lamp. Further, the lubricant can be circulated without depletion, and the life of the machine can be extended.

  That is, in a fixing device having a halogen lamp exposed to a fixing belt to which foreign matter such as shavings generated in the fixing belt is likely to adhere, the foreign matter such as shavings is removed from the inner peripheral surface of the fixing belt, and the lubricant is It can be left on the inner peripheral surface of the fixing belt.

  Further, by forming a groove on the sliding surface with the fixing belt and on the downstream side in the rotation direction of the fixing belt from the nip portion N, foreign matter such as shavings can be removed before the fixing belt is exposed to the halogen lamp. It can be scraped off. In this embodiment, since the cleaning member does not shield between the halogen lamp and the fixing belt, it is possible to efficiently apply radiant heat to the fixing belt. Furthermore, since it is possible to ensure a high cleaning capability with a simple configuration that does not take up space, it is possible to reduce the size of the machine, which also leads to cost reduction of the machine.

<< Second Embodiment >>
In the first embodiment, a groove is formed at an in-plane position of the sliding surface on the downstream side from the nip portion N, and a cleaning member for cleaning the inner peripheral surface of the flexible member is provided in the groove. On the other hand, in the present embodiment, as shown in FIG. 3, the cleaning member 100 that cleans the inner peripheral surface of the flexible member at the out-of-plane position of the sliding surface adjacent to the sliding surface downstream from the nip portion. Is provided. 3, the same reference numerals as those in FIG. 1 denote the same members. The cleaning member 100 is made of the same material as the cleaning member in the first embodiment.

  According to the present embodiment, the cleaning member is further adhered to the upper surface of the sliding member 4 and the side surface of the support member 5 without forming a groove, and the same effect as that of the first embodiment can be achieved at low cost. be able to.

(Modification)
In the embodiment described above, the nip forming part 3 and the guide part 4 as the sliding members are provided separately, but they may be integrated as a sliding member. Further, the nip forming unit 3 and the guide unit 4 may be provided separately, and the nip forming unit 3 may be replaced with a heater (second heating source).

1 .... Fusing belt 2 .... Pressure unit 3 .... Nip forming part 4 .... Guide part 5 .... Supporting member 6 .... Heat source 7 ... Cleaning member 9 ... Groove

Claims (10)

A rotatable flexible member;
A radiation heating source disposed at a position spaced apart from the flexible member inside the flexible member; a sliding member comprising a sliding surface facing the inner peripheral surface of the flexible member;
A pressure member that forms a nip portion with the sliding member via the flexible member;
An image heating apparatus for passing a recording material through the nip and heating the recording material,
At the downstream side of the nip portion, it is generated by sliding at an in-plane position of the sliding surface or an out-of-plane position of the sliding surface adjacent to the sliding surface, and adheres to the inner peripheral surface of the flexible member. An image heating apparatus provided with a cleaning member for cleaning foreign matter. A rotatable flexible member;
A radiation heating source disposed at a position separated from the flexible member inside the flexible member, and a sliding surface facing the inner peripheral surface of the flexible member, the sliding surface being lubricated A sliding member to which the agent is applied;
A pressure member that forms a nip portion with the sliding member via the flexible member;
An image heating apparatus for passing a recording material through the nip and heating the recording material,
On the downstream side of the nip portion, the lubricant is left in the in-plane position of the sliding surface or the out-of-plane position of the sliding surface adjacent to the sliding surface, and is generated by sliding. An image heating apparatus comprising a cleaning member for cleaning foreign matter adhering to the inner peripheral surface of a flexible member.   The image heating apparatus according to claim 1, wherein the cleaning member is provided in a groove in the surface of the sliding surface.   The image heating apparatus according to claim 1, wherein the cleaning member is formed of an elastic body.   The image heating apparatus according to claim 4, wherein the cleaning member is formed of a foamed rubber material.   The image heating apparatus according to claim 5, wherein the unevenness of the cleaning member is 10 μm to 100 μm.   The sliding member includes a nip forming portion and a curved guide portion that is provided on the upstream side and the downstream side of the nip forming portion and guides the inner peripheral surface of the flexible member. The image heating apparatus according to claim 1.   The nip forming part is formed of a heat conductive first material heated by the radiation heating source, and the guide part is formed of a heat insulating second material. Image heating device.   The image heating apparatus according to claim 8, wherein the nip forming part is heated by the radiation heating source through an opening of the guide part. The image heating apparatus according to claim 1, wherein the radiation heating source is a heat ray or a halogen lamp.