CN108463777B

CN108463777B - Fixing device and image forming apparatus including the same

Info

Publication number: CN108463777B
Application number: CN201680076405.0A
Authority: CN
Inventors: 铃木康夫; 山田贵之
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2015-12-22
Filing date: 2016-10-19
Publication date: 2021-09-14
Anticipated expiration: 2036-10-19
Also published as: EP3380895A1; JP2017116650A; KR20170074738A; EP3380895B1; EP3380895A4; JP6792331B2; CN108463777A

Abstract

Provided is a fixing device for preventing an increase in torque when a fixing belt starts to be driven. The fixing device may include: a fixing belt capable of rotating; a pressure roller configured to pressure-contact an outer circumferential surface of the fixing belt and form a fixing nip between the pressure roller and the fixing belt. The contact member is located inside the fixing belt and includes a contact portion that contacts an inner circumferential surface of the fixing belt. The contact portion includes a surface having a plate shape facing the pressure roller and a plurality of protrusions protruding from the surface toward the pressure roller.

Description

Fixing device and image forming apparatus including the same

Technical Field

The present disclosure relates to a fixing device and an image forming apparatus including the same.

Background

In the image forming apparatus, a recording medium supplied from a supply unit is supplied to a transfer unit, and a toner image formed on the transfer unit is secondarily transferred to the recording medium. After the toner image is transferred to the recording medium, the toner disposed on the recording medium is melted and fixed by a fixing unit (e.g., a fixing device). The recording medium on which the toner is fixed is discharged from a discharge unit located downstream.

A conventional fixing device (for example, a fixing device included in the image forming apparatus of patent document 1) is formed by a belt press method and includes an endless fixing belt and an elastic roller (for example, a pressure roller) as a pair of members for forming a nip. The fixing device may include a fixing member disposed on an inner circumferential surface of the fixing belt, and a load of the elastic roller may be applied to the fixing member.

[ patent document 1 ]

Japanese patent laid-open No. 2001-42670

However, according to the conventional technique disclosed in patent document 1, when the fixing device is not used for a long period of time or is used again for a predetermined period of time after the use of the fixing device has been stopped, since the fixing belt and the fixing member are in close contact with each other, a torque required to drive the fixing belt may be increased.

Disclosure of the invention

Technical problem

A fixing device (for example, a fixing device using a belt press method) and an image forming apparatus including the fixing device are provided, which can prevent an increase in torque required to drive a fixing belt.

Technical scheme for solving technical problem

According to an aspect of the present disclosure, a fixing device includes: a fixing belt capable of rotating; a pressure roller configured to pressure-contact an outer circumferential surface of the fixing belt and form a fixing nip between the pressure roller and the fixing belt; and a contact member located inside the fixing belt and including a contact portion contacting an inner circumferential surface of the fixing belt, wherein the contact portion includes a reference surface having a plate shape facing the pressure roller and a plurality of protrusions protruding from the reference surface toward the pressure roller.

The plurality of protrusions may form: a first row including a plurality of protrusions arranged in a width direction of the fixing belt and spaced apart from each other; and a second row spaced from the first row in a moving direction along which the fixing belt moves, including a plurality of protrusions arranged in a width direction of the fixing belt and spaced from each other, the plurality of protrusions of the first row and the second row being alternately arranged in the moving direction of the fixing belt at the fixing nip.

A length of each of the plurality of protrusions in a width direction of the fixing belt may be equal to or greater than a distance between adjacent ones of the plurality of protrusions in the width direction of the fixing belt.

A length of each of the plurality of protrusions in a width direction of the fixing belt may be equal to or greater than 0.55mm, and a pitch between adjacent ones of the plurality of protrusions in the width direction of the fixing belt may be equal to or greater than 1.1 mm.

The fixing device may further include a lubricant distributed between the reference surface and the plurality of protrusions.

The plurality of protrusions may have a belt shape extending in a width direction of the fixing belt.

Each of the plurality of protrusions may have a portion inclined at a predetermined angle with respect to a width direction of the fixing belt.

The contact portion may include a plurality of lubricant supporting protrusions for distributing lubricant between the reference surface and an inner circumferential surface of the fixing belt, wherein the plurality of lubricant supporting protrusions extend in a moving direction along which the fixing belt moves and are arranged on both end portions in a width direction of the fixing belt.

The plurality of lubricant supporting protrusions may be disposed outside an image forming area of the recording medium on which the electronic toner image is formed in a width direction of the fixing belt and inside the fixing nip.

The contact may include a base and a surface layer stacked on the base, at least a portion of the base including at least one of aluminum, stainless steel, Liquid Crystal Polymer (LCP), and polyphenylene sulfide (PPS), and at least a portion of the surface layer including at least one of Polytetrafluoroethylene (PTFE), Perfluoroalkoxy (PFA) fluorine synthetic resin, and modifications thereof.

The contact portion may include a base having a plate shape, which may include aluminum and have a thickness equal to or greater than 0.2mm and equal to or less than 0.5 mm.

The contact portion may include a base having a plate shape, which may include stainless steel and have a thickness equal to or greater than 0.1mm and equal to or less than 0.3 mm.

The fixing device may further include: a lubricant supplying portion at an inlet of the fixing nip, through which the fixing belt is introduced, and configured to supply a lubricant to the contact portion; and a film thickness adjusting portion at an outlet of the fixing nip through which the fixing belt is discharged, the film thickness adjusting portion defining a shape of the fixing belt when the fixing belt rotates by contacting an inner circumferential surface of the fixing belt, and adjusting a film thickness of the lubricant by being adhered to the inner circumferential surface of the fixing belt.

The film thickness regulating portion may include a regulating portion extending in a diameter direction of the fixing belt, wherein the regulating portion protrudes outward in the diameter direction of the fixing belt beyond a nip surface on which outer circumferential surfaces of the pressure roller and the fixing belt contact each other.

The fixing device may further include a separation member configured to separate a recording medium attached to an outer circumferential surface of the fixing belt, wherein the separation member is located at an outlet of the fixing nip through which the fixing belt is discharged, and the plurality of protrusions are located between the contact member and the separation member.

The film thickness adjusting portion may include a guide surface that contacts an inner peripheral surface of the fixing belt, and the guide surface may extend in a circumferential direction of the fixing belt.

The film thickness adjusting section may include: an edge portion that is located on an end portion of the guide surface and scrapes a lubricant adhering to an inner peripheral surface of the fixing belt; and a lubricant receiving portion that is located between the contact member and the edge portion and receives the lubricant scraped by the edge portion.

The edge portion may include an inclined surface inclined at a predetermined angle with respect to a tangent line contacting an inner circumferential surface of the fixing belt.

The fixing device may further include a separation member configured to separate a recording medium attached to an outer circumferential surface of the fixing belt, wherein the separation member is located at an outlet of the fixing nip through which the fixing belt is discharged, and the edge portion is located between the contact member and the separation member.

Brief description of the drawings

These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a diagram of an image forming apparatus including a fixing device according to an embodiment;

fig. 2 is a sectional view of a fixing device using a belt press method according to an embodiment;

FIG. 3 is an enlarged cross-sectional view of a fixing nip according to an embodiment;

fig. 4 is an enlarged perspective view of a contact portion of a contact member according to an embodiment;

fig. 5A to 5C are enlarged plan views of protrusions of the contact portion according to the embodiment;

fig. 6 is an enlarged perspective view of a contact portion of a contact member according to an embodiment;

fig. 7A to 7C are enlarged plan views of protrusions of the contact portion according to the embodiment;

fig. 8 is a graph showing torque generated when the fixing belt starts to be driven according to the embodiment;

fig. 9 is a sectional view of a fixing device according to an embodiment;

fig. 10 is an enlarged sectional view of a film thickness adjusting section according to the embodiment;

fig. 11 is a sectional view of a fixing device according to an embodiment; and

fig. 12 is an enlarged sectional view of an edge portion of the film thickness adjustment member according to the embodiment.

Best Mode for Carrying Out The Invention

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the drawings, the same elements or portions are denoted by the same reference numerals, and a repetitive description thereof will not be given.

The image forming apparatus 1 according to the embodiment can form a color image by using magenta, yellow, cyan, and black. As shown in fig. 1, an image forming apparatus 1 according to an embodiment may include: a recording medium supply unit 10 that supplies a recording medium P; a developing device 20 that develops the electrostatic latent image; a transfer unit 30 that secondarily transfers the toner image to a recording medium P; a photosensitive drum 40 as an electrostatic latent image bearing member having a circumferential surface on which an image is formed; and a fixing device 50 that fixes the toner image to the recording medium P.

The recording medium supply unit 10 may receive the recording medium P on which the image is finally recorded and may supply the recording medium P to the supply path R1. In this case, a plurality of recording media P may be stacked and stored in the cassette K. The recording medium supply unit 10 may supply the recording medium P to the secondary transfer region R2 when the toner image transferred to the recording medium reaches the secondary transfer region R2.

The four developing devices 20 may be arranged according to colors. Each of the developing devices 20 may include a developing roller 21 that presses toner against the photosensitive drum 40. The developing device 20 sufficiently charges the toner by mixing the toner with the carrier particles and presses the developer generated due to the mixture of the toner and the carrier particles against the developing roller 21. Next, when the developer is conveyed to the region facing the photosensitive drum 40 due to the rotation of the developing roller 21, the toner of the developer pressed by the developing roller 21 moves to the electrostatic latent image formed on the circumferential surface of the photosensitive drum 40 to develop the electrostatic latent image.

To secondarily transfer the toner image formed by the developing device 20 to the recording medium P, the transfer unit 30 may be supplied to the secondary transfer region R2. The transfer unit 30 may include: a transfer belt 31; rotating

rollers

31a, 31b, 31c, and 31d that rotate the transfer belt 31; a primary transfer roller 32 allowing the transfer belt 31 to be held between the primary transfer roller 32 and the photosensitive drum 40; and a secondary transfer roller 33 allowing the transfer belt 31 to be held between the secondary transfer roller 33 and the rotating roller 31 d.

The transfer belt 31 is an endless belt rotated by rotating

rollers

31a, 31b, 31c, and 31 d. The primary transfer roller 32 may be provided to apply pressure to the photosensitive drum 40 from the inner periphery of the transfer belt 31. The secondary transfer roller 33 may be provided to apply pressure from the outer periphery of the transfer belt 31 to the rotating roller 31 d.

The photosensitive drum 40 is an electrostatic latent image bearing member having a circumferential surface on which an image is formed. In the image forming apparatus for forming a color image according to the embodiment, four photosensitive drums 40 corresponding to, for example, magenta, yellow, cyan, and black may be arranged in a direction in which the transfer belt 31 moves (referred to as a moving direction). As shown in fig. 1, a developing device 20, a charging roller 41, an exposure unit 42, and a cleaning unit 43 may be arranged around each photosensitive drum 40.

The charging roller 41 can uniformly charge the surface of the photosensitive drum 40 by using a predetermined potential. The exposure unit 42 may expose the surface of the photosensitive drum 40 charged by the charging roller 41, and in this case, the surface of the photosensitive drum 40 may be exposed to correspond to an image to be formed on paper as the recording medium P. Accordingly, the potential of a portion of the surface of the photosensitive drum 40 exposed by the exposure unit 42 can be changed, and thus an electrostatic latent image can be formed. The four developing devices 20 may receive toner from toner tanks 22 arranged to correspond to the four developing devices 20, may develop an electrostatic latent image formed on the photosensitive drum 40 by using the toner supplied from the toner tanks 22, and may generate a toner image. For example, magenta, yellow, cyan, and black toners may be filled in the four toner tanks 22, respectively. The cleaning unit 43 may recover the toner remaining on each photosensitive drum 40 after the toner image formed on the photosensitive drum 40 is primarily transferred to the transfer belt 31.

The fixing device 50 can attach and fix the toner image secondarily transferred from the transfer belt 31 to the recording medium P onto the recording medium P. The fixing device 50 according to the embodiment may include, for example: a fixing belt 51 that heats the recording medium P; and a pressure roller (e.g., an elastic roller) 52 that applies pressure to the fixing belt 51. The fixing belt 51 and the pressure roller 52 may be formed to have a cylindrical shape. A fixing nip 53 as a contact portion may be formed between the fixing belt 51 and the pressure roller 52, and the toner image may be melted and fixed onto the recording medium P as the recording medium P passes through the fixing nip 53 in the feeding direction.

Further, the image forming apparatus 1 according to the embodiment may further include discharge rollers 71 and 72, the discharge rollers 71 and 72 discharging the recording medium P on which the toner image is fixed by the fixing device 50 to the outside of the image forming apparatus 1.

The operation of the image forming apparatus 1 will now be described. When an image signal of an image to be recorded is input to the image forming apparatus 1, the controller of the image forming apparatus 1 may uniformly charge the surface of the photosensitive drum 40 to a predetermined potential by using the charging roller 41 according to the received image signal.

Next, an electrostatic latent image may be formed by emitting a laser beam to the surface of the photosensitive drum 40 using the exposure unit 42.

The toner image may be formed when the developing device 20 develops the electrostatic latent image. When the photosensitive drum 40 and the transfer belt 31 face each other, the toner image is primarily transferred from the photosensitive drum 40 to the transfer belt 31. The toner images formed on the four photosensitive drums 40 may be sequentially stacked on the transfer belt 31 to form one stacked toner image.

Next, the stacked toner images may be supplied to a secondary transfer region R2 where the rotating roller 31d and the secondary transfer roller 33 face each other, and may be secondary-transferred to the recording medium P supplied from the recording medium supply unit 10 in the secondary transfer region R2.

The recording medium P to which the stacked toner images are secondarily transferred may be supplied to the fixing device 50. When the recording medium P passes between the fixing belt 51 and the pressure roller 52, the stacked toner images may be melted and fixed onto the recording medium P by applying heat and pressure to the recording medium P.

Next, the recording medium P may be discharged to the outside of the image forming apparatus 1 by the discharge rollers 71 and 72.

The fixing device 50 will now be described in more detail with reference to fig. 2.

As shown in fig. 2, the fixing device 50 may include a fixing belt 51, a pressure roller 52, a contact member (e.g., a fixing member) 54, and a heat source (e.g., a heater) 55. Further, the fixing device 50 may include a separation member 56, and the separation member 56 separates the recording medium P attached to the outer circumferential surface 51a of the fixing belt 51 from the fixing belt 51. The separation member 56 may be disposed in the feeding direction R3 of the recording medium P and may be disposed at an outlet of the fixing nip 53 through which the fixing belt 51 is discharged through the outlet of the fixing nip 53.

As shown in fig. 2 and 3, the fixing nip 53 is a portion where the recording medium P is held between the fixing belt 51 and the pressure roller 52. The fixing nip 53 may include a portion (e.g., a contact portion) closest to the outer circumferential surface 51a of the fixing belt 51 and the outer circumferential surface 52a of the pressure roller 52. Generally, the internal pressure of the fixing nip 53 may be equal to or greater than 0.049MPa and equal to or less than 0.196MPa (e.g., equal to or greater than 0.5 kgf/cm)²And 2.0kgf/cm or less²). The internal pressure of the fixing nip 53 is a pressure applied to the recording medium P held between the fixing belt 51 and the pressure roller 52.

The fixing belt 51 may be a flexible rotating body having a cylindrical shape and may contain, for example, metal. Examples of the metal that may be contained in the fixing belt 51 may include stainless steel. Further, the fixing belt 51 may contain, for example, a synthetic resin.

The fixing belt 51 may include a plurality of materials stacked as shown in fig. 3. The fixing belt 51 may include a base 57, an elastic layer 58 stacked on the base 57, and a surface layer 59 stacked on the elastic layer 58. The base 57 may comprise a metallic material such as stainless steel or nickel. Further, the base 57 may include a synthetic resin such as Polyimide (PI), polyamide-imide (PAI), polyether ether ketone (PEEK), or Liquid Crystal Polymer (LCP).

The elastic layer 58 may comprise, for example, rubber. The surface layer 59 may contain a fluorine synthetic resin. For example, the fluorine synthetic resin may be at least one selected from Polytetrafluoroethylene (PTFE), Perfluoroalkoxy (PFA) fluorine synthetic resin, and modified product (modifier) thereof. The thickness of the base 57 may be, for example, equal to or greater than 20mm and equal to or less than 120 mm. The thickness of the elastic layer 58 may be, for example, equal to or greater than 100mm and equal to or less than 400 mm. The thickness of the surface layer 59 may be, for example, equal to or greater than 10mm and equal to or less than 50 mm.

The pressure roller 52 may be an elastic rotating body having a cylindrical shape and may contain, for example, rubber (e.g., an elastic material). Pressure roller 52 may include: an elastic layer 61 comprising an elastic material; and a surface layer 62 formed on the elastic layer 61. Further, a rotation shaft 60 may be provided to be inserted into the pressure roller 52 and pass through the pressure roller 52.

The contact member 54 may be disposed inside the fixing belt 51 and may apply pressure to the fixing belt 51 along with the pressure roller 52. An elastic force may be applied to the contact member 54 by using, for example, a spring member (not shown), and the contact member 54 may be pressed toward the pressure roller 52 due to the elastic force. However, the embodiment is not limited thereto, and an elastic force may be applied to the pressure roller 52 and the pressure roller 52 may be pressed toward the contact member 54. Alternatively, while an elastic force may be applied to the pressure roller 52 and the pressure roller 52 may be pressed toward the contact member 54, an elastic force may be applied to the contact member 54 and the contact member 54 may be pressed toward the pressure roller 52.

The contact member 54 may extend along the rotational axis of the fixing belt 51 having a cylindrical shape, and may include a structure 63 disposed inside the fixing belt 51, a support portion 64 fixed to the structure 63, and a fixed slide member 65 supported by the support portion 64.

The cross-sections of the structure 63, the support 64 and the fixed sliding member 65 taken in a direction perpendicular to their longitudinal direction may have, for example

And (4) shape. The structure 63 may include a pair of side walls 63a extending in a direction perpendicular to the feeding direction R3 of the recording medium P and a body portion 63b connecting end portions of the pair of side walls 63 a. The main body portion 63b of the structure 63 may have a plate shape, and the thickness direction of the main body portion 63b may be a rotational center O to which the fixing belt 51 is coupled₅₁And the rotation center O of the pressure roller 52₅₂In the direction in which the straight line L1 extends.

The support portion 64 may include a pair of side walls 64a extending in a direction perpendicular to the feeding direction R3 of the recording medium P and a body portion 64b connecting end portions of the pair of side walls 64 a. The body portion 64b of the support portion 64 may have a plate shape, and the thickness direction of the body portion 64b may be a direction in which the straight line L1 extends. The support portion 64 may be mounted on the structure 63 to be supported by the structure 63, and may be provided to cover a portion of the structure 63 near the pressure roller 52. For example, the body portion 64b of the support portion 64 may cover the body portion 63b of the structure 63, and the pair of side walls 64a of the support portion 64 may cover the pair of side walls 63a of the structure 63.

The fixed slide member 65 may include a pair of side walls 65a extending in a direction perpendicular to the feeding direction R3 of the recording medium P, and a main body portion (e.g., a contact portion) 65b connecting end portions of the pair of side walls 65 a. The main body portion 65b of the fixed slide member 65 may have a plate shape, and the thickness direction of the main body portion 65b may be a direction in which the straight line L1 extends. The fixed slide member 65 may be mounted on the support portion 64 to be supported by the support portion 64, and may be disposed to cover a portion of the support portion 64 adjacent to the pressure roller 52. The main body portion 65b of the fixed slide member 65 may cover the main body portion 64b of the support portion 64, and the pair of side walls 65a of the fixed slide member 65 may cover the pair of side walls 64a of the support portion 64.

The fixed slide member 65 may include a base and a surface layer formed on the base. The base of the stationary slide member 65 may comprise a metallic material, such as aluminum or stainless steel. Further, the fixed slide member 65 may include a synthetic resin having heat resistance, such as LCP or polyphenylene sulfide (PPS).

Further, a fluorine synthetic resin may be applied to the surface of the main body portion 65b of the fixed slide member 65. The fluorine synthetic resin may be at least one selected from PTFE, PFA fluorine synthetic resin and modified products thereof.

As shown in fig. 3, the main body portion 65b of the fixed slide member 65 included in the contact member 54 is a contact portion that contacts the inner peripheral surface 51b of the fixing belt 51. The pressure roller 52 may receive power from a driving motor (not shown) and may rotate about a predetermined rotation axis. An outer circumferential surface 52a of the pressure roller 52 may be disposed at the fixing nip 53 to contact an outer circumferential surface 51a of the fixing belt 51, so that the rotational force of the pressure roller 52 may be transmitted to the fixing belt 51, and the fixing belt 51 may also rotate about a predetermined rotational axis.

At the fixing nip 53, the fixing belt 51 may receive pressure from the pressure roller 52 and may slide while contacting the main body portion 65b of the fixed slide member 65. The fixing belt 51 may form a plane along the main body portion 65b of the fixing slide member 65 at the fixing nip 53 to correspond to the plate shape of the main body portion 65 b. At the fixing nip 53, the moving direction Y of the fixing belt 51 may be the same as the feeding direction R3 of the recording medium P. The nip surface N of the fixing nip 53 is a virtual surface set between the fixing belt 51 and the pressure roller 52.

As shown in fig. 3, 4, and 5A, a plurality of protrusions 67 protruding from the reference surface 66 toward the pressure roller 52 may be provided on the main body portion 65b of the fixed slide member 65. The reference surface 66 as the surface of the main body portion 65b facing the pressure roller 52 may be, for example, perpendicular to the straight line L1. The plurality of protrusions 67 may have, for example, a rectangular shape in plan view and may have, for example, the same size and the same shape.

At the fixing nip 53, the length L of each protrusion 67 in the width direction X of the fixing belt 51 perpendicular to the moving direction Y of the fixing belt 51_X67May be equal to or greater than, for example, 0.55 mm. Further, the pitch (e.g., interval) between the protrusions 67 in the width direction X may be equal to or larger than, for example, 1.1 mm.

Further, the plurality of protrusions 67 may be arranged side by side at regular intervals in the width direction X to form a plurality of rows (for example, a first row X1 and a second row X2). Further, the plurality of protrusions 67 arranged to include rows in the width direction X may be arranged at regular intervals in the moving direction Y. For example, the protrusions 67 of the second row X2 may be arranged at positions corresponding to spaces between the plurality of protrusions 67 of the first row X1. Therefore, the plurality of projections of the first row X1 and the plurality of projections of the second row X2 may be alternately arranged at the fixing nip 53 in the moving direction Y of the fixing belt 51. In this case, the length L of each protrusion 67_X67May be greater than the distance D between the protrusions 67₆₇。

One or more protrusions 67 may be arranged in the moving direction Y of the fixing belt 51. For example, when the plurality of protrusions 67 are viewed in the moving direction Y of the fixing belt 51, the protrusions 67 may be arranged without any impression over the entire width in the width direction X. That is, the main body portion 65b may contact the fixing belt 51 in the feeding direction R3 of the recording medium P along the entire longitudinal direction of the main body portion 65 b. Therefore, in the longitudinal direction of the fixed slide member 65, the load of the pressure roller 52 can be made uniform, and a part of the fixing nip 53 can be prevented from being unloaded.

Height H of each of the plurality of protrusions 67₆₇May be, for example, equal to or greater than 5mm and equal to or less than 30 mm. Height H of each of the plurality of protrusions 67₆₇Is the difference in height between the reference surface 66 and the top surface of the protrusion 67.

When the fixed slide member 65 including the plurality of protrusions 67 includes a metal material, the plurality of protrusions 67 may be formed by using, for example, press working, etching, laser engraving, or the like. Further, when the fixed slide member 65 including the plurality of protrusions 67 includes a synthetic resin material, the plurality of protrusions 67 may be formed by using, for example, injection molding, etching, or laser engraving. The protrusion 67 may be formed by eroding the surface of the material by using a chemical on the surface of the contact portion, performing etching, and performing creping. Further, the plurality of protrusions 67 may be formed by performing etching on the surface of the contact portion to have a geometric shape.

Further, when the plurality of protrusions 67 are formed by using laser engraving, a laser engraving machine that emits laser beams in a plurality of directions may be used. Therefore, a plurality of protrusions 67 having a complicated shape can be formed.

Further, when the base of the fixed slide member 65 includes an aluminum plate material and the thickness of the base is, for example, equal to or greater than 0.2mm and equal to or less than 0.5mm, springback that may occur when press working is performed can be prevented. Therefore, the plurality of protrusions 67 can be formed more accurately.

Further, when the base portion of the fixed slide member 65 includes a stainless steel plate material and the thickness of the base portion is, for example, equal to or greater than 0.1mm and equal to or less than 0.3mm, springback that may occur when press working is performed can be prevented. Therefore, the plurality of protrusions 67 can be formed more accurately.

Due to the fact that according to the embodimentA plurality of protrusions 67 protruding from the reference surface 66 are arranged on the main body portion 65b of the fixed slide member 65 included in the fixing device 50, and therefore the contact area that can be formed between the inner peripheral surface 51b of the fixing belt 51 and the main body portion 65b of the fixed slide member 65 can be reduced. Therefore, an increase in torque that may occur when the fixing belt 51 starts to be driven can be prevented. Further, since friction between the fixed slide member 65 and the fixing belt 51 is reduced, energy consumption that may occur when the fixing belt 51 is driven can be prevented. Further, the sliding resistance can be reduced without placing another member (such as a slide sheet) between the fixed sliding member 65 and the inner peripheral surface 51b of the fixing belt 51. Therefore, the fixing device 50 can be simplified, the manufacturing cost can be reduced, and an increase in torque that may occur when the fixing belt 51 starts to be driven can be prevented. Further, since the plurality of protrusions 67 protruding from the reference surface 66 are provided on the main body portion 65b of the fixed slide member 65, the lubricant can be distributed over the entire reference surface 66 (e.g., non-contact portion) provided around the plurality of protrusions 67, that is, in the space between the plurality of protrusions 67. Therefore, the fixing belt 51 can slide more easily, deterioration of the fixing belt 51 with the lapse of time can be reduced, and the quality of the fixing device 50 can be maintained for a long period of time. Further, the length of each protrusion 67 contacting the inner peripheral surface 51b of the fixing belt 51 in the width direction X may be equal to or greater than 0.55 mm. Further, the pitch P between adjacent ones of the plurality of projections 67₆₇May be equal to or greater than 1.1 mm. Since the plurality of protrusions 67 are included in the fixing device 50 according to the embodiment as described above, the contact power between the fixing belt 51 and the fixing slide member 65 can be reduced, and thus an increase in torque that may occur when the fixing belt 51 is driven can be prevented. Further, since the fixed slide member 65 is used, the load applied by the pressure roller 52 in a state where the fixing belt 51 is driven can be uniformized, and a part of the fixing nip 53 can be prevented from being applied with no load. Further, when the plurality of protrusions 67 are included in the fixing device 50, the internal pressure of the fixing nip 53 may be equal to or less than 0.098 MPa.

A first variation of the protrusion will now be described with reference to figure 5B. The protrusions are not limited to the rectangular shape, and may be protrusions 68 having a diamond shape in plan view.

The diagonal line L2, which is the longer diagonal line from among the diagonal lines of the protrusions 68 having the diamond shapes, may be arranged to run in the moving direction Y of the fixing belt 51, for example. The diagonal line L3, which is the shorter one of the diagonal lines from the protrusions 68, may be arranged to run in the width direction X of the fixing belt 51, for example.

The length L of each projection 68 in the width direction X of the fixing belt 51 perpendicular to the moving direction Y of the fixing belt 51_X68May be equal to or greater than 0.55mm, for example. Further, a pitch P in the width direction X of the fixing belt between adjacent ones of the projections 68₆₈May be, for example, equal to or greater than 1.1 mm. Further, the length L of the projection 68_X68May be greater than the distance D between the protrusions 68₆₈。

Now, a second modification of the protrusion will be described with reference to fig. 5C. The protrusion 69 according to the second modification may have a circular shape in plan view.

The plurality of protrusions 69 may be arranged side by side in a width direction X (e.g., a first direction) of the fixing belt 51 to form rows, and the plurality of protrusions 69 arranged in a row in the width direction X may form a plurality of columns in a moving direction Y (e.g., a second direction) of the fixing belt 51. Further, the plurality of projections 69 of adjacent columns in the width direction X of the fixing belt 51 may be arranged so as not to correspond to each other in the width direction X of the fixing belt 51. The plurality of protrusions 69 may be arranged in a matrix. Further, the direction in which the projections 69 are formed in a row is not limited to the width direction X of the fixing belt 51 and the moving direction Y of the fixing belt 51, and may be other directions. Further, the first direction and the second direction may be directions perpendicular to each other or may cross at a predetermined angle instead of 90 °.

The diameter L of each projection 69_X69May be equal to or greater than 0.55mm, for example. Further, a pitch P in the width direction X between adjacent ones of the projections 69₆₉May be, for example, equal to or greater than 1.1 mm. Further, the diameter L of the projection 69_X69May be greater than the distance D69 between the projections 69.

Now, the protrusion of the fixed slide member according to the second embodiment will be described with reference to fig. 6. A plurality of protrusions 82 and lubricant supporting protrusions 83 may be provided on the main body portion (e.g., contact portion) 81b of the fixed slide member 81 according to the second embodiment. The protrusions 82 may extend in the width direction X of the fixing belt 51 and may be arranged to be separated from each other in the moving direction Y of the fixing belt 51. Further, the lubricant supporting protrusions 83 may extend in the moving direction Y of the fixing belt and may be disposed on both ends of the fixed sliding member 81 in the width direction X of the fixing belt 51.

The lubricant supporting protrusion 83 may be disposed outside the protrusion 82 in the width direction X of the fixing belt 51. In the fixing device 50 according to the embodiment, the lubricant may be distributed between the main body portion 81b of the fixed slide member 81 and the inner circumferential surface 51b of the fixing belt 51. The lubricant supporting protrusion 83 may be a lubricant supporting portion for supporting the lubricant distributed between the main body portion 81b of the fixed sliding member 81 and the inner circumferential surface 51b of the fixing belt 51. The lubricant supporting protrusion 83 may be disposed outside the image forming area of the recording medium P in the width direction X and may be disposed inside the embossing load area to which a load is applied by the pressure roller 52. The image forming area of the recording medium P is an area on the recording medium P where a toner image can be formed. The nip load region is a region where the fixing belt 51 and the pressure roller 52 can contact each other.

The width L of each protrusion 82_Y82May be equal to or greater than 0.55mm, for example. Further, a pitch P in the moving direction Y of the fixing belt 51 between adjacent ones of the projections 82₈₂May be, for example, equal to or greater than 1.1 mm. The width of each lubricant supporting protrusion 83 may be, for example, equal to or greater than the width L of each protrusion 82_Y82。

As described above, when the lubricant supporting protrusions 83 having a belt shape are disposed at both end portions of the fixing belt 51 in the width direction X, the lubricant distributed between the main body portion 81b and the inner circumferential surface 51b of the fixing belt 51 may have a restricted movement in the width direction X of the fixing belt 51. Therefore, the lubricant can be prevented from leaking to the outside of the fixing nip 53 in the width direction X of the fixing belt 51.

Now, a modification having a protrusion with a band shape will be described with reference to fig. 7A to 7C. The protrusions 85 to 87 having a band shape of fig. 7A to 7C are third to fifth modifications of the protrusion 82 having a band shape of fig. 6. Fig. 7A to 7C show portions having band-shaped projections 85 to 87 from the center to the end in the longitudinal direction.

As shown in fig. 7A, the projection 85 having a band shape according to the third modification may be inclined such that a predetermined angle exists between the extending direction in which the projection 85 extends and the width direction X of the recording medium P. The protrusion 85 having a belt shape is not perpendicular to the moving direction Y of the fixing belt 51. The protrusion 85 having a band shape may be arranged to be inclined in the longitudinal direction over the entire length. In this case, the inclination angle of the protrusion 85 having a band shape may be constant or may vary depending on the position in the longitudinal direction.

As shown in fig. 7B, the protrusion 86 having a band shape according to the fourth modification may include a central portion 86a and end portions 86B, respectively, in the longitudinal direction. The central portion 86a may have a length of 1/3 that is about the entire length of the protrusion 86 in the longitudinal direction. The central portion 86a may be disposed perpendicular to the moving direction Y of the fixing belt 51. The end portions 86b may be provided at both end portions of the central portion 86a to be inclined with respect to the central portion 86 a. For example, a portion of the end portion 86b close to the central portion 86a may be disposed at an entrance of the fixing nip 53, that is, upstream in the moving direction Y of the fixing belt 51, and a portion of the end portion 86b far from the central portion 84a may be disposed at an exit of the fixing nip 53, that is, downstream in the moving direction Y of the fixing belt 51. Further, in this case, the angle formed between each end portion 86b and the central portion 86a may be, for example, but not limited to, equal to or greater than 5 ° and equal to or less than 30 °.

Further, the protrusions having the belt shape may be arranged such that portions ranging from the central portion to both end portions are inclined in the longitudinal direction, without including a portion of the central portion perpendicular to the moving direction Y of the fixing belt. For example, the protrusion may be arranged to have a V shape having a center of the entire length as an apex. Even in this case, the central portion may be disposed at the entrance of the fixing nip 53, that is, upstream in the moving direction Y of the fixing belt 51, and the outer portions may be disposed at the exit of the fixing nip 53, that is, downstream in the moving direction Y of the fixing belt 51.

Further, the protrusion having a belt shape may include a portion of a central portion perpendicular to the moving direction Y of the fixing belt 51 in the longitudinal direction, and a curved portion that curves outward from the central portion in the longitudinal direction may be provided at an exit of the fixing nip 53, that is, downstream in the moving direction Y of the fixing belt 51.

As shown in fig. 7C, the protrusions 87 having a band shape according to the fifth modification may be bent to have a wave form. The protrusion 87 may include a plurality of bends. In this case, the curved portions curved in opposite directions may be alternately arranged in the width direction X of the fixing belt 51. In this case, both outer end portions in the longitudinal direction may be provided at the outlet of the fixing nip 53, that is, may be provided downstream in the moving direction Y of the fixing belt 51.

Now, torque that can be generated when the fixing belt is driven will be described with reference to fig. 8. Fig. 8 is a graph showing torque generated when the fixing belt 51 is driven. The horizontal axis in fig. 8 represents the load (N) at the fixing nip 53, and the vertical axis in fig. 8 represents the torque (N · m) that can be generated when the fixing belt 51 is driven.

In embodiment 1, a fixing device including a fixed slide member 65 on which a plurality of protrusions 67 having a rectangular shape are formed as shown in fig. 4 is used. In comparative example 1, a fixing device including a fixed sliding member having a plate shape on which a protrusion is not formed was used. The fixing device in embodiment 1 is the same as that in comparative example 1 except that there is a protrusion. Next, the maximum value of the torque generated when the fixing belt 51 is driven may be measured and plotted on a graph.

In embodiment 1 and comparative example 1, the torque was measured a plurality of times by changing the load of the fixing nip 53. In fig. 8, a curve G1 corresponds to the measurement result of embodiment 1, and a curve G2 corresponds to the measurement result of comparative example 1. For example, it was found that the torque of example 1 was 30% or more smaller than that of comparative example 1 when the load was about 300N.

Now, a fixing device 90 according to a third embodiment will be described with reference to fig. 9. In describing the fixing device 90 according to the third embodiment, the same elements or structures as those in the first and second embodiments will not be explained again.

The fixing device 90 may include a fixing belt 51, a pressure roller 52, a contact member 54, and a heat source (e.g., a heater) 55. Further, the fixing device 90 may include a separation member 56 that separates the recording medium P adhering to the outer circumferential surface 51a of the fixing belt 51 from the fixing belt 51. The separation member 56 may be provided at an outlet of the fixing nip 53 in the feeding direction R3 of the recording medium P.

The contact member 54 may be disposed inside the fixing belt 51 and may apply pressure to the recording medium P in conjunction with the pressure roller 52. The contact member 54 may extend in the axial direction of the fixing belt 51 having a cylindrical shape, and may include a structure 63 extending in the axial direction, a support portion 64 supported on the structure 63, and a fixed slide member 65 supported by the support portion 64. The fixed slide member 65 may include a plurality of protrusions 67.

Further, the fixing device 90 may include a reflection plate 92 covering an outer surface of the contact member 54. The reflection plate 92 may extend in the axial direction of the fixing belt 51, and a section of the reflection plate 92 taken in a direction perpendicular to the longitudinal direction may have

And (4) shape. The reflection plate 92 may include a pair of sidewalls 92a extending in a direction perpendicular to the feeding direction of the recording medium P and a connection portion 92b connecting ends of the pair of sidewalls 92 a. In fig. 9, the ends of a pair of side walls 92a (particularly, near the heat source 55) may be connected to each other by a connection portion 92 b.

The pair of side walls 92a may be installed to cover the pair of side walls 65a of the fixed slide member 65. The reflection plate 92 may reflect radiant heat applied from the heat source 55 to the inner circumferential surface 51b of the fixing belt 51. Further, the reflection plate 92 may reflect radiant heat applied from the inner circumferential surface 51b of the fixing belt 51 to the inner circumferential surface 51b of the fixing belt 51.

Further, the fixing device 90 may further include: a lubricant supplying portion 93 provided upstream of the main body portion 65b as a contact portion of the fixed slide member 65, that is, at an inlet of the fixing nip 53; and a film thickness adjusting section 94 provided downstream of the main body section 65b, that is, at an outlet of the fixing nip 53 in the moving direction Y of the fixing belt 51.

The lubricant supplying portion 93 may be provided at an upstream end portion of the main body portion 65b of the fixed slide member 65 in the moving direction Y of the fixing belt 51, that is, at an inlet of the fixing nip 53, and may be supported on the fixed slide member 65. The lubricant supplying part 93 may have a length corresponding to a width of the fixing belt 51 in an axial direction of the fixing belt 51. The lubricant may be filled in the lubricant supply part 93, and a portion of the lubricant supply part 93 from which the lubricant is leached may be applied to the inner circumferential surface 51b of the fixing belt 51. Further, the lubricant adhering to the inner circumferential surface 51b may move as the fixing belt 51 moves, and may be supplied between the main body portion 65b and the inner circumferential surface 51 b.

The film thickness adjusting section 94 may be provided at an end portion downstream of the main body portion 65b of the fixed slide member 65 in the moving direction Y of the fixing belt 51, that is, at an outlet of the fixing nip 53, and may be supported by the support section 64. The film thickness adjusting section 94 may have a length corresponding to the width of the fixing belt 51 in the axial direction of the fixing belt 51.

Further, the film thickness adjusting portion 94 may contact the inner circumferential surface 51b of the fixing belt 51 and may adjust the shape of the fixing belt 51 when the fixing belt 51 rotates. The film thickness adjusting portion 94 may extend in the diameter direction of the fixing belt 51 to protrude outward, and may be provided to press the inner peripheral surface 51 b. Further, the film thickness adjusting section 94 may adjust the film thickness of the lubricant passing through the main body section 65b and moving to the outlet of the fixing nip 53. That is, the lubricant adhering to the inner peripheral surface 51b of the fixing belt 51 may have a restricted movement to the outlet of the fixing nip 53 due to the film thickness regulating portion 94.

The film thickness adjusting section 94 may include a nonwoven fabric. The nonwoven fabric may comprise, for example, heat resistant fibers. The nonwoven fabric may have a heat resistance of, for example, 300 ℃ or higher. Further, the nonwoven fabric may have flame retardancy in addition to heat resistance, and the UL94 flammability rating of the nonwoven fabric may be equal to or greater than V-0. In addition, the thickness of the nonwoven fabric may beFor example equal to or greater than 0.8m and equal to or less than 4.5 mm. Further, the weight of the nonwoven fabric may be, for example, 200g/m or more². Further, aramid fibers may be included as the micro heat-resistant fibers in the nonwoven fabric.

For example, the film thickness adjusting section 94 may be formed by winding a nonwoven fabric around a member having a rod shape. Further, the film thickness adjusting section 94 may be formed by stacking a plurality of layers formed of a nonwoven fabric. Further, the film thickness adjusting section 94 may be formed of a material such as a synthetic resin.

In the fixing device 90 according to the embodiment, the lubricant may be supplied from the upstream of the fixed slide member 65, that is, from the inlet of the fixing nip 53, and may be distributed between the main body portion 65b of the fixed slide member 65 and the inner circumferential surface 51b of the fixing belt 51. Therefore, the frictional resistance between the main body portion 65b of the fixed slide member 65 and the inner peripheral surface 51b of the fixing belt 51 can be reduced, the torque of the fixing belt 51 can be prevented from increasing, and the torque can be reduced even when the fixing device 90 starts to be driven or is driven.

In the fixing device 90 according to the embodiment, since the lubricant may be distributed between the main body portion 65b of the fixed slide member 65 and the inner circumferential surface 51b of the fixing belt 51, friction dust generated due to friction between the fixed slide member 65 and the fixing belt 51 may be prevented when compared with a case where the lubricant is not distributed, and thus contamination due to the friction dust may be prevented. For example, although the upper surface layer is separated and thus abrasion dust may be generated on the inner circumferential surface 51b of the fixing belt 51, the fixing device 90 according to the embodiment may prevent generation of the abrasion dust because the lubricant is distributed as described above. Therefore, the amount of the friction dust moving to the outlet of the fixing nip 53 together with the remaining lubricant can be reduced, and thus contamination of the inside of the fixing belt 51 can be prevented.

Further, in the fixing device 90 according to the embodiment, the film thickness of the lubricant adhering to the inner peripheral surface 51b of the fixing belt 51 can be adjusted by the film thickness adjusting section 94. The lubricant having a thickness equal to or greater than the predetermined thickness may contact the film thickness adjusting section 94 and thus may not move to the outlet of the fixing nip 53. The film thickness adjusting section 94 may include a nonwoven fabric, and the remaining lubricant adhering to the inner peripheral surface 51b of the fixing belt 51 may be removed by the nonwoven fabric. Further, a small amount of abrasion dust that may be generated due to friction between the fixed sliding member 65 and the fixing belt 51 may also be removed by the nonwoven fabric included in the film thickness adjusting section 94 together with the remaining lubricant.

With the removal of the remaining lubricant and the wear dust as described above, contamination due to the remaining lubricant and the wear dust can be prevented. Therefore, since the surplus lubricant and the abrasion dust are prevented from adhering to the inner peripheral surface 51b of the fixing belt 51, the surplus lubricant and the abrasion dust can be prevented from falling from the inner peripheral surface 51b of the fixing belt 51. Further, the amount of remaining lubricant and abrasion dust adhering to the reflection plate 92 can be reduced, and thus the reflection efficiency can be prevented from being lowered. As a result, since radiant heat from the heat source 55 can be efficiently transmitted to the fixing belt 51, the fixing belt 51 can be heated more efficiently and the toner image can be fixed to the recording medium P more reliably.

Further, in the fixing device 90 according to the embodiment, since the film thickness regulating portion 94 contacts the inner peripheral surface 51b of the fixing belt 51, the shape of the rotating fixing belt 51 can be defined. The fixing belt 51 may receive an external pressure in the diameter direction due to the film thickness adjusting section 94, and thus may define the shape of the fixing belt 51. Therefore, the rotational displacement of the fixing belt 51 can be defined. The rotational displacement refers to a displacement of the fixing belt 51 that may occur when the fixing belt 51 rotates, specifically, a displacement in the thickness direction of the fixing belt 51. In the fixing device 90 according to the embodiment, since the rotational displacement of the fixing belt 51 can be defined, unnecessary contact between the fixing belt 51 and the separation member 56 disposed close to the outer circumferential surface 51a of the fixing belt 51 can be prevented. Further, since the rotation shape (e.g., orbit) of the fixing belt 51 may be stable, abrupt contact between the fixing belt 51 and the separation member 56 may be prevented.

Further, in the fixing device 90 according to the embodiment, since the rotational shape of the fixing belt 51 disposed near the exit of the fixing nip 53 can be more stably defined, the front end portion of the separation member 56 can be disposed closer to the outer circumferential surface 51a of the fixing belt 51. Therefore, the recording medium P adhering to the outer peripheral surface 51a of the fixing belt 51 can be separated more reliably.

Further, since the film thickness adjusting section 94 can prevent the remaining lubricant and the abrasion dust adhering to the fixing belt 51 from passing through the film thickness adjusting section 94 and moving to the outlet of the fixing nip 53 and can more stably adjust the rotational shape of the fixing belt 51, it is possible to dispense with providing an additional structure, and thus it is possible to simplify the structure of the fixing device 90.

Fig. 10 is an enlarged sectional view showing a modification of the film thickness adjusting section 94. The film-thickness regulating portion 94 may include a regulating portion 94a protruding toward the fixing belt 51 as shown in fig. 10. According to the embodiment, the regulating portion 94a as a shape regulating portion having a surface facing the inner peripheral surface 51b of the fixing belt 51 may protrude outward in the diameter direction of the fixing belt 51. The regulating portion 94a may protrude beyond the main body portion 65b of the fixed slide member 65 toward the pressure roller 52. Further, the regulating portion 94a according to the embodiment may protrude beyond the nip face N toward the pressure roller 52. Therefore, the contact position between the regulating portion 94a and the fixing belt 51 may be outside the nip surface N in the diameter direction. When the regulating portion 94a protrudes outward beyond the nip surface N as described above, the film thickness regulating portion 94 can more stably contact the fixing belt 51 and can more surely define the rotational displacement of the fixing belt 51. Further, the remaining lubricant and wear dust that may adhere to the inner peripheral surface 51b of the fixing belt 51 can be reduced more reliably.

Now, a fixing device 100 according to a fourth embodiment will be explained with reference to fig. 11. The fixing device 100 of fig. 11 differs from the fixing device 90 according to the third embodiment in that: the structure of the film thickness adjusting section 102 is different from that of the film thickness adjusting section 94, and a lubricant receiving section 103 for receiving the lubricant recovered from the film thickness adjusting section 102 is provided. When describing the fixing device 100 of the fourth embodiment, the same elements or structures as those in the first to third embodiments will not be explained again.

The fixing device 100 according to the embodiment may include a film thickness adjusting member 101, and the film thickness adjusting member 101 includes a film thickness adjusting section 102. The film thickness regulating member 101 may extend in the axial direction of the fixing belt 51. In this case, the film thickness adjusting member 101 may have a length corresponding to the width of the fixing belt 51 in the axial direction of the fixing belt 51. The film-thickness adjusting member 101 may include a supporting portion 101a in addition to the film-thickness adjusting portion 102. The support portion 101a may be provided to be supported on the contact member 54.

The supporting portion 101a may be formed to have, for example, a column shape, and may extend in the axial direction of the fixing belt 51. The support portion 101a may be provided so as to be supported on, for example, the side wall 64a at the downstream of the support portion 64 (for example, downstream in the moving direction Y of the fixing belt 51). However, embodiments are not limited thereto, and the support portion 101a may be provided to be supported on the structure 63 of the contact member 54.

The film thickness adjusting section 102 may be provided to be supported by the supporting section 101a (for example, the film thickness adjusting section 102 may be integrally formed with the supporting section 101 a). The film thickness adjusting section 102 may include a guide surface 102a, an edge portion 102b, and an inclined surface 102 c. The film thickness adjusting section 102 may protrude outward from the supporting section 101a in the diameter direction of the fixing belt 51. The film thickness adjusting portion 102 may include a guide surface 102a that contacts the inner peripheral surface 51b of the fixing belt 51. For example, the guide surface 102a may be formed around the rotation center O of the fixing belt 51₅₁Extend in the circumferential direction. Further, the guide surface 102a may have a predetermined length in the circumferential direction of the fixing belt 51. For example, the length of the guide surface 102a may be 10% of the circumferential length of the fixing belt 51.

Further, the guide surface 102a may include, for example, synthetic resin. The guide surface 102a may include a synthetic resin having high heat resistance and high flame retardancy, such as PPS, polyethylene terephthalate (PET), LCP, or PEEK. Further, the guide surface 102a may include a non-woven fabric.

Fig. 12 is an enlarged sectional view of the edge portion 102b of the film thickness adjusting member 101. As shown in fig. 12, an edge portion 102b as an end portion of the guide surface 102a may be provided between the front end portion of the separating member 56 and the main body portion 65b of the fixed slide member 65.

The rotation center O of the edge portion 102b facing the fixing belt 51₅₁May be an inclined surface 102c inclined with respect to a tangent line L51b contacting the inner peripheral surface 51b of the fixing belt 51. Inclination angle of straight line L102c following inclined surface 102c to tangent L51bDegree theta_102cMay be, for example, but not limited to, equal to or greater than 15 ° and equal to or less than 45 °.

The fixing device 100 may include a lubricant receiving portion 103 that receives the lubricant recovered from the film thickness adjusting portion 102. The lubricant receiving portion 103 may be provided downstream of the fixed slide member 65, that is, may be provided at the exit of the fixing nip 53, and may also be provided upstream of the edge portion 102b in the moving direction Y of the fixing belt 51. The lubricant receiving portion 103 may include an opening close to the inner circumferential surface 51b of the fixing belt 51.

The lubricant receiving portion 103 may receive the remaining lubricant in a space formed between the side wall 65a (see fig. 1) of the fixed slide member 65 and the film thickness adjusting portion 102. The lubricant that moves after adhering to the fixing belt 51 may reach the edge portion 102b of the film thickness adjusting portion 102 and may be separated from the fixing belt 51. The separated lubricant may be received in the lubricant receiving portion 103 after moving along the inclined surface 102c of the edge portion 102 b.

Contamination due to the remaining lubricant and the abrasion dust can be prevented by the fixing device 100 of the fourth embodiment.

Further, in the fixing device 100 of the fourth embodiment, although the film thickness regulating member 101 and the support portion 64 are separate elements, the film thickness regulating member 101 and the support portion 64 may be integrated into one member. Therefore, the number of components in the fixing device 100 can be reduced, and the structure of the fixing device 100 can be simplified.

The embodiment is not limited thereto, and various modifications may be made without departing from the scope of the inventive concept.

In the fixing device 100, the fixing belt 51 may include a base 57 formed of a synthetic resin, and the lubricant supplying part 93 may supply a black lubricant (black lubricant). Therefore, the black lubricant may be applied to the inner circumferential surface 51b of the fixing belt 51. When the fixing belt 51 is formed of a synthetic resin that does not allow for the black surface treatment, the absorption of the radiant heat of the fixing belt 51 can be increased by applying a black lubricant to the inner circumferential surface 51b of the fixing belt 51. Therefore, the heating efficiency can be improved, and the image can be stably fixed to the recording medium by using the fixing device 100. The black lubricant may be a fluorine-based lubricant to which carbon black or a black dye is added. However, the embodiment is not limited thereto, and the lubricant may be colored black by using other methods.

Further, in the embodiment, the protrusion may be included in the main body portion 65b as the contact portion of the fixed slide member 65, or may not be included in the main body portion 65b of the fixing device 90 of the third embodiment or the fixing device 100 of the fourth embodiment.

Further, the shape of the protrusion is not limited to the diamond shape, the circular shape, and the band shape, and may be any of other shapes such as a trapezoidal shape or an elliptical shape.

Further, the pitch between the plurality of protrusions is not limited to 1.1mm or more and may be less than 1.1 mm. Further, the pitch between the protrusions may be constant or may vary depending on, for example, the position in the width direction X. Further, the length of each protrusion contacting the fixing belt is not limited to 0.5mm or more, and may be less than 0.55 mm.

According to an embodiment, there is provided a fixing device that can prevent an increase in torque that may be generated when a fixing belt starts to be driven, and an image forming apparatus including the same.

While one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope defined by the following claims.

Claims

1. A fixing device through which a recording medium capable of recording an electronic toner image passes, comprising:

a fixing belt rotatable and including an inner circumferential surface and an outer circumferential surface;

a pressure roller pressure-contacting an outer circumferential surface of the fixing belt and forming a fixing nip between the pressure roller and the fixing belt to pass the recording medium in a moving direction of the fixing belt; and

a contact member located inside the fixing belt and including a contact portion contacting an inner circumferential surface of the fixing belt,

wherein the contact portion includes a surface having a plate shape facing the pressure roller and a plurality of protrusions protruding from the surface toward the pressure roller,

wherein the fixing device further includes a lubricant distributed between the surface of the contact portion and the plurality of protrusions,

wherein the contact portion includes a plurality of lubricant supporting protrusions to support distribution of the lubricant between the surface of the contact portion and an inner circumferential surface of the fixing belt,

the plurality of lubricant supporting protrusions extend in a moving direction in which the fixing belt moves, and are arranged on both end portions in a width direction of the fixing belt.

2. The fixing device according to claim 1, wherein the plurality of protrusions form:

first rows of protrusions arranged in a width direction of the fixing belt and spaced apart from each other; and

second rows of protrusions spaced apart from the first rows of protrusions in a moving direction along which the fixing belt moves, the second rows of protrusions being arranged in a width direction of the fixing belt and spaced apart from each other,

the plurality of protrusions of the first row of protrusions and the second row of protrusions are alternately arranged in a moving direction of the fixing belt at the fixing nip.

3. The fixing device according to claim 2, wherein lengths of the plurality of protrusions in a width direction of the fixing belt are equal to or greater than a distance between adjacent ones of the plurality of protrusions in the width direction of the fixing belt.

4. The fixing device according to claim 1, wherein each of the plurality of protrusions has a belt shape extending in a width direction of the fixing belt, and wherein each of the plurality of protrusions has a portion inclined at an angle with respect to the width direction of the fixing belt.

5. The fixing device according to claim 1, wherein the plurality of lubricant supporting protrusions are arranged outside an image forming area of the recording medium on which the electronic toner image is formed in a width direction of the fixing belt and inside the fixing nip.

6. The fixing device according to claim 1, wherein the contact portion includes a base portion, and the surface of the contact portion is a surface layer stacked on the base portion,

at least a portion of the base comprises at least any one or combination of aluminum, stainless steel, Liquid Crystal Polymer (LCP), and polyphenylene sulfide (PPS), and

at least a part of the surface layer comprises at least any one or a combination of Polytetrafluoroethylene (PTFE), Perfluoroalkoxy (PFA) fluorine synthetic resin, and a modified product thereof.

7. The fixing device according to claim 1, wherein the contact portion includes a base portion,

the surface of the contact portion is a surface layer, the base portion has a plate shape corresponding to a plate shape of the surface layer, the base portion contains aluminum and has a thickness equal to or greater than 0.2mm and equal to or less than 0.5 mm.

8. The fixing device according to claim 1, wherein the contact portion includes a base portion,

the surface of the contact portion is a surface layer, the base portion has a plate shape corresponding to a plate shape of the surface layer, the base portion contains stainless steel and has a thickness equal to or greater than 0.1mm and equal to or less than 0.3 mm.

9. The fixing device according to claim 1, further comprising:

a lubricant supplying portion at an inlet of the fixing nip, the fixing belt being introduced through the lubricant supplying portion to supply lubricant to the contact portion, an

A film thickness adjusting portion at an outlet of the fixing nip, through which the fixing belt is discharged to define a shape of the fixing belt in response to rotation of the fixing belt by contacting an inner circumferential surface of the fixing belt, and to adjust a film thickness of the lubricant by being adhered to the inner circumferential surface of the fixing belt.

10. The fixing device according to claim 9, wherein the film thickness regulating portion includes a regulating portion extending in a diameter direction of the fixing belt,

the regulation portion protrudes outward in a diameter direction of the fixing belt beyond a nip surface of the fixing nip portion on which the pressure roller and an outer circumferential surface of the fixing belt contact each other.

11. The fixing device according to claim 10, further comprising a separation member that separates a recording medium adhering to an outer peripheral surface of the fixing belt,

wherein the separation member is located at an outlet of the fixing nip through which the fixing belt is discharged, and the plurality of protrusions are located between the contact member and the separation member.

12. The fixing device according to claim 9, wherein the film thickness regulating portion includes a guide surface that contacts an inner peripheral surface of the fixing belt, the guide surface extending in a circumferential direction of the fixing belt.

13. The fixing device according to claim 12, wherein the film thickness adjusting section includes: an edge portion on an end portion of the guide surface to scrape a lubricant adhering to an inner peripheral surface of the fixing belt; and a lubricant receiving portion located between the contact member and the edge portion to receive the lubricant scraped by the edge portion.

14. The fixing device according to claim 13, wherein the edge portion includes an inclined surface that is inclined at an angle with respect to a tangent line contacting an inner circumferential surface of the fixing belt.

15. The fixing device according to claim 14, further comprising a separation member that separates a recording medium adhering to an outer peripheral surface of the fixing belt,

wherein the separation member is located at an outlet of the fixing nip through which the fixing belt is discharged, and the edge portion is located between the contact member and the separation member.