JP5538265B2 - Fixing apparatus and image forming apparatus equipped with the same - Google Patents

Description

  The present invention relates to a fixing device for fixing unfixed toner on a surface of a recording medium such as paper by heating and pressing. The present invention also relates to an image forming apparatus such as a copying machine, a printer, or a facsimile equipped with the fixing device.

  In an image forming apparatus such as a copying machine, a printer, or a facsimile, a thermal fixing method is widely used as a method for fixing an unfixed toner image transferred to a sheet as a recording medium in a transfer unit. In the thermal fixing method, a pair of rotating bodies composed of rollers and belts are brought into pressure contact with each other to form a fixing nip portion. The thermal fixing method uses a heating body to heat one or both of the rotating bodies as a heated body, and fixes the toner on the paper by inserting a paper carrying an unfixed toner image into the fixing nip portion. It is. As a heat fixing type fixing device, a roller that directly contacts a toner image on a paper surface of two rollers constituting a pair of rollers in pressure contact with each other is used as a heat roller, and a heating body such as a halogen lamp is provided on the heat roller. The built-in one is common.

  In addition, a heat fixing type fixing device may use a belt formed endlessly on one of a pair of rotating bodies forming a fixing nip portion. In many cases, this belt rotates in accordance with the rotation of the opposite rotating body by being pressed against the other facing rotating body. For this reason, it is necessary to support this portion from the inside so that the portion of the fixing nip portion of the belt is firmly in contact with the counter rotating body.

  If another member is placed on the inner surface of the belt and supported in order to make the fixing nip portion of the belt firmly contact the opposite rotating body, the sliding portion between the other member and the inner surface of the belt will slide. Dynamic friction occurs. If the load due to this friction becomes relatively high, the belt may slip with respect to the counter-rotating member and cause fixing wrinkles or paper jam. Therefore, a technique for reducing friction by supplying a lubricant to the sliding portion has been proposed, and an example of such a fixing device can be seen in Patent Document 1.

  In the fixing device described in Patent Document 1, a belt rotating body having a belt (endless belt) is opposed to a heating roll having a heat source (halogen lamp) inside to form a fixing nip portion. In this fixing device, a sliding member comes into contact with the inner surface of the belt at the sliding portion of the fixing nip portion, and a pad body containing oil is provided on the inner side. Then, the sliding portion between the inner surface of the belt and the sliding member is lubricated with oil that has oozed from the pad body to reduce sliding friction.

JP 2005-37681 A

  Here, in addition to pressure, temperature is also an important condition in order to effectively lubricate oil as a lubricant in the sliding portion. That is, it is necessary to keep the oil at an appropriate temperature and a suitable viscosity. In the fixing device described in Patent Document 1, since the heating roll and the belt rotating body face each other, the fixing nip portion can be directly heated by a heat source inside the heating roll. That is, it is possible to expect an increase in the temperature of oil that has oozed out on the belt inner surface of the fixing nip portion. However, when the fixing device has a configuration in which the fixing nip portion cannot be directly heated using a heat source for heating the heating roller, the viscosity of the lubricant in the fixing nip portion is high when the fixing device is started at a relatively low temperature. There is a risk of becoming. Therefore, there is a possibility that the lubricant cannot be effectively lubricated at the fixing nip portion when the fixing device is activated.

  The present invention has been made in view of the above points, and in a fixing device using an endless belt as one rotating body for forming a fixing nip portion, fixing is performed using a heat source for heating the rotating body. An object of the present invention is to provide a fixing device capable of always and effectively lubricating a lubricant for reducing sliding friction generated on the inner surface of a belt of a fixing nip portion even when the nip portion cannot be directly heated. . It is another object of the present invention to provide an image forming apparatus having such a fixing device with improved reliability.

  In order to solve the above-described problems, the present invention includes an endless belt, and a pressure member that forms a fixing nip portion that presses against the belt and allows a recording medium to pass therethrough. In a fixing device for fixing an unfixed toner image carried on a recording medium while the recording medium is inserted and conveyed through the fixing nip portion, a sliding member that contacts the belt inner surface of the fixing nip portion, and the sliding member And a lubricant impregnated member for soaking the lubricant between the belt and the inner surface of the belt, and a lubricant impregnated member heating body for heating the lubricant impregnated member.

  According to this configuration, the lubricant contained in the lubricant-impregnated member is directly heated by the lubricant-impregnated member heating body. Therefore, even when the fixing device cannot directly heat the fixing nip portion using a heat source for heating the belt and the pressure member, the viscosity of the lubricant is reduced at the start-up in a relatively low temperature state, Lubricating action by the lubricant is enhanced. As a result, the sliding friction is constantly reduced on the inner surface of the belt at the fixing nip portion.

  Further, in the fixing device having the above-described structure, after the heating of the lubricant-impregnated member by the lubricant-impregnated member heating body is started, the belt is rotated to start insertion of the recording medium into the fixing nip portion. did.

  According to this configuration, the lubricating action of the inner surface of the belt at the fixing nip portion is improved before the belt is rotated. Therefore, the effect of reducing sliding friction on the inner surface of the belt at the fixing nip portion is further enhanced.

  Further, the fixing device having the above configuration includes a support member that supports the lubricant-impregnated member, and the lubricant-impregnated member heating body heats the support member.

  According to this configuration, the heat of the lubricant-impregnated member heating body is transmitted to the lubricant-impregnated member via the support member. Therefore, the lubricant-impregnated member is heated while being supported by the support member.

  In the fixing device configured as described above, the lubricant-impregnated member heating body is a resistance heating element.

  According to this configuration, the lubricant-impregnated member is heated by the resistance heating element that is relatively easy to obtain and install. Therefore, the sliding friction on the inner surface of the belt at the fixing nip portion is always reduced by a simple configuration.

  In the fixing device having the above configuration, the lubricant-impregnated member heating body heats the support member by electromagnetic induction heating.

  According to this configuration, it is possible to prevent a problem that the lubricant impregnated member heating body is heated to an unnecessary portion other than the lubricant impregnated member. Therefore, the lubricant-impregnated member is efficiently heated, and the lubricating action by the lubricant is enhanced.

  In the fixing device having the above configuration, at least a portion of the support member that receives a magnetic field by electromagnetic induction heating is formed of a magnetic shunt alloy.

  When the magnetic shunt alloy reaches a certain temperature, the magnetic flux passes therethrough and no current flows and heat is not generated. Therefore, this configuration prevents an increase in temperature more than necessary. Therefore, the lubricant-impregnated member is heated more efficiently, and the lubricating action by the lubricant is enhanced.

  In the present invention, the fixing device having the above configuration is mounted on the image forming apparatus.

  According to this configuration, in the image forming apparatus, the viscosity of the lubricant is lowered on the inner surface of the belt of the fixing nip portion, including when the fixing device is started at a relatively low temperature, and the lubricating action is increased. Is reduced.

  According to the configuration of the present invention, in the fixing device using an endless belt as one member for forming the fixing nip portion, the fixing nip portion cannot be directly heated using the heat source for heating the rotating body. Even so, it is possible to provide a fixing device capable of always and effectively lubricating the lubricant for reducing the sliding friction generated on the belt inner surface of the fixing nip portion. In addition, it is possible to provide an image forming apparatus with such a fixing device with improved reliability.

1 is a schematic vertical sectional front view of an image forming apparatus equipped with a fixing device according to a first embodiment of the present invention. FIG. 2 is a vertical sectional front view of the fixing device shown in FIG. 1. FIG. 3 is a partially enlarged vertical sectional front view showing a fixing nip portion of the fixing device of FIG. 2. FIG. 6 is a vertical sectional front view of a fixing device according to a second embodiment of the present invention. FIG. 6 is a vertical sectional front view of a fixing device according to a third embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, the image output operation of the image forming apparatus equipped with the fixing device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image forming apparatus. A solid line arrow in FIG. 1 indicates a sheet conveyance path and a conveyance direction.

  As shown in FIG. 1, a paper feed unit 3 is disposed at the lower part of the main body 2 of the image forming apparatus 1. The paper feed unit 3 includes a normal general-purpose paper feed cassette 3a and a large-capacity paper feed cassette 3b which are paper storage units. The general-purpose paper feed cassette 3a is arranged below the large-capacity paper feed cassette 3b, and two general-purpose paper feed cassettes 3a are arranged in the vertical direction. The large-capacity paper feed cassette 3b is disposed above the general-purpose paper feed cassette 3a, and two large-capacity paper feed cassettes 3b are arranged at the same height in the horizontal direction.

  These paper feeding cassettes 3a and 3b accommodate and store paper P such as cut paper before printing which is a recording medium. For example, the general-purpose paper feed cassette 3a can store about 500 sheets of paper P, and the large-capacity paper feed cassette 3b can store about 1500 sheets of paper P. The sheets P are separated and sent one by one toward the upper right of the sheet feeding cassettes 3a and 3b in FIG. The paper feed cassettes 3 a and 3 b can be pulled out horizontally from the front side of the main body 2. When the paper P is replenished to the paper feed cassettes 3a and 3b, the paper P is stacked inside from the upper surface direction of the paper feed cassettes 3a and 3b pulled out.

  A manual paper feed tray 3 c is provided on the right side of the main body 2 and slightly above the main body 2. The manual feed tray 3c is difficult to pass through a bent conveyance path such as paper, cardboard, OHP sheets, envelopes, and postcards of a size not included in the general-purpose paper feed cassette 3a or the large capacity paper feed cassette 3b. What you want to feed by hand is placed one by one.

  Further, the image forming apparatus 1 includes a vertical conveyance unit 4 therein. The vertical conveyance unit 4 is located on the right side in the paper feeding direction in terms of the two types of paper feeding cassettes 3a and 3b, and is located on the left side in terms of the manual paper feeding tray 3c. The paper P sent out from the paper feed cassettes 3a and 3b is vertically upward along the side surface of the main body 2 by the vertical transport unit 4, and the paper P sent out from the manual paper feed tray 3c is substantially horizontally left to the transfer unit 5. Be transported. Of the two large-capacity paper feed cassettes 3b, the paper P sent out from the left-side large-capacity paper feed cassette 3b is sent to the right substantially horizontally right above the right-side large-capacity paper feed cassette 3b. It is transported vertically upward by the vertical transport unit 4 along the side surface of the main body 2.

  On the other hand, a document conveying device 6 is mounted on the upper surface of the main body 2 of the image forming apparatus 1, and an image reading unit 7 is mounted in the main body 2 below the main body 2. When a user copies an original, an original on which images such as characters, figures, and patterns are drawn is stacked on the original conveying device 6 or placed on a contact glass (not shown) on the upper surface of the image reading unit 7. . In the document conveying device 6, the documents are separated one by one and sent out, and the image is read by the image reading unit 7. An image is read by scanning light in the image reading unit 7 on the document on the contact glass.

  The reading of the document image and the start of printing are executed using the operation panel 8 provided at the upper part of the main body 2 and on the front side of the image reading unit 7. The operation panel 8 includes a display unit 8a, a setting unit 8b, and a start button 8c. The display unit 8a is composed of a liquid crystal panel or the like. For example, the display unit 8a accepts printing condition settings such as the type and size of paper used for printing, the number of copies, enlargement / reduction, and presence / absence of double-sided printing, resolution, density, color information, and the like. While displaying image data information and image processing conditions, it also functions as a notification unit for instructing the user about precautions and error messages. The setting unit 8b functions as an input unit for inputting user-specific user information, while the user can set image processing conditions, a storage destination of image data, and the like. The start button 8c is a button for accepting reading of an original image and start of printing.

  The image data information of the document is subjected to image processing via a control unit (not shown) or the like, which will be described later, and then sent to an exposure unit 9 disposed below the image reading unit 7. The exposure unit 9 irradiates the image forming unit 10 with laser light controlled based on the image data.

  An image forming unit 10 and a transfer unit 5 are provided on the downstream side of the vertical conveyance unit 4 in the sheet conveyance direction and below the exposure unit 9. In the image forming unit 10, an electrostatic latent image of a document image is formed by the laser light emitted from the exposure unit 9, and a toner image is developed from the electrostatic latent image. The toner image formed by the image forming unit 10 is transferred by the transfer unit 5 to the pre-printing paper P sent in synchronization by the vertical conveyance unit 4.

  A fixing device 20 is provided on the left side of the transfer unit 5 and downstream of the sheet conveyance direction. The paper P carrying the unfixed toner image in the transfer unit 5 is sent to the fixing device 20, and the toner image is heated and pressed by a heating belt and a pressure roller to be fixed.

  A sheet guide 11 is provided on the downstream side of the fixing device 20 and in the vicinity of the left side surface of the main body 2. When the double-sided printing is not performed, the paper P discharged from the fixing device 20 is discharged from the paper guide unit 11 to a paper discharge tray 12 provided outside the left side surface of the image forming apparatus 1.

  A paper reversing unit 13 for performing double-sided printing is provided below the portion from the image forming unit 10 to the paper guiding unit 11 and above the paper feeding unit 3. In the case of performing duplex printing, the sheet P discharged from the fixing device 20 after completion of printing on the first surface is sent to the sheet reversing unit 13 through the sheet guiding unit 11. The paper P sent to the paper reversing unit 13 is then switched in the transport direction for printing on the second side, sent to the right side of the main body 2 and sent again to the transfer unit 5 via the vertical transport unit 4. It is done.

  Next, a detailed configuration of the fixing device 20 will be described with reference to FIG. 2 in addition to FIG. FIG. 2 is a vertical sectional front view of the fixing device 20.

  The fixing device 20 includes a fixing unit 30, a heating unit 40, and a pressure unit 50 as shown in FIG.

  The fixing unit 30 includes a heating belt 31 for heating the unfixed toner carried on the paper P. The heating belt 31 is an endless belt, and its width is configured to be slightly longer than the width of the paper P that can be used for printing in the image forming apparatus 1.

  The heating belt 31 has an outer diameter of 20 to 50 mm, for example, and a base material formed of an induction heating layer of copper, nickel, or stainless steel (SUS) having a thickness of 20 to 50 μm. An elastic layer of 100 to 500 μm made of, for example, silicone rubber is formed on the outer surface of the base material. Further, in order to improve smoothness and toner releasability on the outer surface of the elastic layer, for example, a 100-500 μm mold release made of a fluorine-based resin such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) is used. Forming a layer. In some cases, the inner surface of the heating belt 31 is coated with polyimide, for example.

  A pad 32 is provided in a portion corresponding to the fixing nip N inside the heating belt 31. The pad 32 has substantially the same length as the heating belt 31 in the paper width direction, and is supported by a support member 33 fixed to a housing (not shown) of the fixing device 20. The pad 32 is pressed by the pressure roller 51 via the heating belt 31 and is in contact with the inner surface of the heating belt 31 in the fixing nip portion N. Details of the pad 32 will be described later.

  The support member 33 is formed of a member having a substantially I-shaped vertical cross section extending from a position facing the heating unit 40 having substantially the same length as the heating belt 31 in the paper width direction to the position of the pad 32. Consists of copper.

  The heating unit 40 is disposed at a position facing the pressure unit 50 across the fixing unit 30. The heating unit 40 includes an exciting coil 41 and a core 42, and heats the heating belt 31 by electromagnetic induction.

  The exciting coil 41 is formed by winding a litz wire, for example, of 300 enamel wires having a diameter of 0.1 mm, along the axis of the heating belt 31, that is, in a direction perpendicular to the paper surface of FIG. A portion of the exciting coil 41 that faces the heating belt 31 is formed to be curved along the outer surface of the heating belt 31.

  A core 42 for increasing the magnetic field is disposed outside the exciting coil 41 wound in this manner. The core 42 is made of a member having a high magnetic permeability such as ferrite.

  For example, a high frequency power source (not shown) having a rated power of 1500 W and a frequency of 20 to 50 kHz is connected to the exciting coil 41. When a high frequency current is passed through the exciting coil 41, a magnetic field is generated. Since most of the generated magnetic flux passes through the core 42, which is a highly permeable member, the magnetic field can be strengthened. When the generated magnetic flux passes through the induction heating layer of the heating belt 31, an eddy current flows around the magnetic flux in the induction heating layer, and Joule heat is generated due to its electric resistance. In this way, the heating belt 31 is heated by the heating unit 40 to generate heat.

  The pressure unit 50 includes a pressure roller 51 that is a pressure member. The pressure roller 51 is configured with substantially the same length as the heating belt 31 in the paper width direction.

  The pressure roller 51 includes an elastic layer 51b made of silicone rubber or sponge on the outside of a metal core 51a made of metal such as stainless steel. In some cases, a release layer made of a fluorine resin such as PFA is formed on the surface of the pressure roller 51.

  The pressure roller 51 obtains power from a driving device such as a motor (not shown), and rotates in the counterclockwise direction in FIG. 2, that is, the surface corresponding to the fixing nip portion N moves in the downstream direction of the sheet conveyance direction. Further, the pressure roller 51 is urged toward and pressed against the heating belt 31 by the action of an urging mechanism (not shown) to form a fixing nip portion N having a predetermined width in the sheet conveying direction. The sheet P carrying unfixed toner passes through the fixing nip N. The heating belt 31 does not rotate by directly obtaining power from a driving device or the like, but rotates according to the rotation of the pressure roller 51 by contacting the pressure roller 51. The heating belt 31 rotates clockwise in FIG.

  Next, a detailed configuration of the fixing nip N of the fixing device 20 will be described with reference to FIG. 3 in addition to FIGS. 1 and 2. FIG. 3 is a partially enlarged vertical sectional front view showing the fixing nip portion N of the fixing device 20.

  In the fixing nip portion N, the pressure roller 51 is in pressure contact with the heating belt 31 as shown in FIG. As a result, the pad 32 is pressed by the pressure roller 51 via the heating belt 31 as described above, and is in contact with the inner surface of the heating belt 31 of the fixing nip portion N.

  Here, the pad 32 includes a sliding member 32a, a lubricant-impregnated member 32b, and a lubricant-impregnated member heating body 32c.

  The sliding member 32a is configured in a sheet shape or a thin plate shape using, for example, PTFE (polytetrafluoroethylene) or polyimide as a base material, and is in direct contact with the inner surface of the heating belt 31 of the fixing nip portion N. The sliding surface of the sliding member 32a facing the sliding portion F between the sliding member 32a and the inner surface of the heating belt 31 is formed to have a surface roughness Ra of 10 to 100 μm so as to reduce sliding friction. The sliding member 32a is provided with a plurality of holes (not shown) penetrating from the front and back, that is, from the inner surface side of the heating belt 31 to the lubricant-impregnated member 32b side.

  The lubricant-impregnated member 32b is made of, for example, silicone rubber containing silicone oil as a lubricant. The lubricant-impregnated member 32b is provided at a position where the sliding member 32a is separated from the inner surface of the heating belt 31 of the fixing nip N. Touching. The silicone oil in the lubricant-impregnated member 32b oozes out by the action of pressure and heat, and further oozes the sliding portion F through a plurality of holes provided in the sliding member 32a. The pressure for allowing the silicone oil to ooze from the lubricant-impregnated member 32 b is obtained when the pressure roller 51 is in pressure contact with the heating belt 31. The lubricant contained in the lubricant-impregnated member 32b is not limited to silicone oil, and may be other lubricants such as grease.

  The lubricant-impregnated member heating body 32c is provided at a position separating the sliding member 32a and the lubricant-impregnated member 32b from the inner surface of the heating belt 31 of the fixing nip N, and is in contact with the lubricant-impregnated member 32b. The lubricant-impregnated member heating body 32c is composed of a resistance heating element made of, for example, a nickel-chromium metal heating element or a non-metallic heating element of silicon carbide, and generates Joule heat due to its electric resistance.

  As a result, the silicone oil contained in the lubricant-impregnated member 32b is directly heated by the lubricant-impregnated member heating body 32c. Accordingly, even if the fixing nip portion N cannot be directly heated using the heating unit 40 for heating the heating belt 31 as in the fixing device 20, the viscosity of the silicone oil at the start-up in a relatively low temperature state. Decreases, and the lubricating action of silicone oil increases. As a result, the sliding friction is always reduced in the sliding portion F on the inner surface of the heating belt 31 of the fixing nip portion N.

  Further, since the lubricant impregnated member 32b is heated by a resistance heating element that is relatively easy to obtain and install, the sliding friction in the sliding portion F is always reduced by a simple configuration.

  Further, when the fixing device 20 performs the fixing operation, after the heating of the lubricant impregnated member 32b by the lubricant impregnated member heating body 32c is started, the pressure roller 51 and the heating belt 31 are rotated to rotate the fixing nip of the paper P. Insertion into part N is started. Thereby, before the heating belt 31 is rotated, the lubricating action of the inner surface of the heating belt 31 in the fixing nip portion N is improved. Therefore, the effect | action which reduces the sliding friction in the sliding part F is improved further.

  According to the configuration of the above embodiment, in the fixing device 20 using the endless heating belt 31 as one member for forming the fixing nip portion N, the heating unit 40 that is a heat source for heating the heating belt 31. Even if the fixing nip portion N cannot be directly heated by using the fixing device, the fixing device can always and effectively lubricate the silicone oil for reducing the sliding friction generated on the inner surface of the heating belt 31 of the fixing nip portion N. 20 can be provided. In addition, it is possible to provide the image forming apparatus 1 with such a fixing device 20 with improved reliability.

  Next, a fixing device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a vertical sectional front view of the fixing device. Since the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 3, the same reference numerals are given to the same components as those of the first embodiment. The description will be omitted.

  As shown in FIG. 4, the fixing device 20 according to the second embodiment includes a support member 34 having a bowl shape that is recessed toward the pad 32. The support member 34 is configured to have substantially the same length as the heating belt 31 and the pad 32 in the paper width direction. Note that the lubricant impregnated member heating body 32 c as in the first embodiment is not included in the pad 32.

  A lubricant-impregnated member heating body 35 is disposed at a location separating the support member 34 from the pad 32. The lubricant-impregnated member heating body 35 is composed of, for example, a halogen heater that extends along the axial direction of the heating belt 31 and heats the support member 34 by its radiant heat. Thereby, the heat of the lubricant-impregnated member heating body 35 is transmitted to the lubricant-impregnated member 32 b through the support member 34. Therefore, it is possible to heat the lubricant-impregnated member 32 b while supporting it by the support member 34.

  Next, a fixing device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a vertical sectional front view of the fixing device. Note that the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. The description will be omitted.

  In the fixing device 20 according to the third embodiment, the pad 32 is supported by a support member 33 having the same shape as that of the first embodiment as shown in FIG. Note that the lubricant impregnated member heating body 32 c as in the first embodiment is not included in the pad 32.

  The support member 33 is formed of a member having a substantially I-shaped vertical cross section extending from a position facing the heating unit 40 having substantially the same length as the heating belt 31 to the position of the pad 32 in the paper width direction. A portion to be heated 33 a made of a magnetic shunt alloy is provided at a location facing the heating portion 40 of the support member 33. The heated portion 33 a is a portion that is affected by a magnetic field due to electromagnetic induction heating of the heating portion 40, and is heated by the heating portion 40. The lubricant-impregnated member 32b is heated while being supported by the support member 33, and the heating unit 40 is a heating body for the heating belt 31 and also has a function of a lubricant-impregnated member heating body.

  Thereby, generation | occurrence | production of the malfunction heated to an unnecessary location other than the lubricant impregnation member 32b by the lubricant impregnation member heating body is prevented. Accordingly, the lubricant-impregnated member 32b is efficiently heated, and the lubricating action by the lubricant is enhanced. Further, when the magnetic shunt alloy reaches a certain temperature, the magnetic flux passes through and no current flows and heat is not generated. Therefore, this configuration prevents an unnecessarily high temperature rise. Therefore, the lubricant-impregnated member 32b is heated more efficiently, and the lubricating action by the lubricant is enhanced.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the above embodiment, electromagnetic induction heating is used as the heating method of the heating unit 40, but the method of heating the heating belt 31 is not limited to electromagnetic induction heating, and other heating methods may be used. I do not care.

  In the above-described embodiment of the present invention, the image forming apparatus for monochrome printing using only black toner as the image forming apparatus 1 has been described as an example. However, the image forming apparatus to which the invention is applied is described above. It is not limited to the model, and may be a tandem type or rotary type image forming apparatus for color printing that includes an intermediate transfer belt and can superimpose a plurality of colors to form an image.

  The present invention is an apparatus for fixing unfixed toner to the surface of a recording medium such as paper by heating and pressurizing, and fixing using an endless belt as one member for forming a fixing nip portion. Available in the device.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Fixing apparatus 30 Fixing part 31 Heating belt 32 Pad 32a Sliding member 32b Lubricant impregnation member 32c Lubricant impregnation member heating body 33, 34 Support member 33a Heated part 35 Lubricant impregnation member heating body 40 Heating part 50 Pressure part 51 Pressure roller (Pressure member)
N Fixing nip F Sliding part

Claims (7)

An endless belt, and a pressure member that forms a fixing nip portion that presses against the belt and allows the recording medium to pass therethrough. The recording medium is inserted into the heated fixing nip portion and conveyed. While fixing the unfixed toner image carried on the recording medium,
A sliding member that contacts the inner surface of the belt of the fixing nip;
Lubrication that is provided in contact with the sliding member at a position spaced apart from the belt inner surface of the fixing nip portion so as to allow the lubricant to bleed between the sliding member and the belt inner surface. An agent-impregnated member;
A plurality of holes provided in the sliding member and penetrating from the belt inner surface side of the sliding member to the lubricant-impregnated member side;
A lubricant-impregnated member heating body for heating the lubricant-impregnated member;
A fixing device comprising:   2. The heating of the lubricant-impregnated member by the lubricant-impregnated member heating body is started, and then the belt is rotated to start insertion of a recording medium into the fixing nip portion. Fixing device. A support member for supporting the lubricant-impregnated member;
The fixing device according to claim 1, wherein the lubricant-impregnated member heating body heats the support member.   The fixing device according to claim 1, wherein the lubricant-impregnated member heating body is a resistance heating element.   The fixing device according to claim 3, wherein the lubricant impregnated member heating body heats the support member by electromagnetic induction heating.   The fixing device according to claim 5, wherein at least a portion of the support member that receives a magnetic field by electromagnetic induction heating is made of a magnetic shunt alloy.   An image forming apparatus comprising the fixing device according to claim 1.