JP2016057527A - Pressing device for fixing device, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressing device that can suppress a variation in pressing force, a fixing device, and an image forming apparatus.SOLUTION: A fixing device includes: a rotatable heating roll 66; an endless belt 72 that is driven to travel by the rotation of the heating roll 66; a holding member 118 that is arranged on the opposite side of the heating roll 66 and inside the endless belt 72; and a pressing device including a first pressure member 114 that is provided on an exit side 70 from which a recording medium 128 is ejected, a second pressure member 116 that is provided on an entrance side 68 into which the recording medium 128 is inserted, and a support member 104 that has a first area 106 to which the first pressure member 114 is fixed and a second area 108 to which the second pressure member 116 is fixed, where the first area 106 and second area 108 are integrally formed, the support member 104 supporting so as to press the second pressure member 116 against the heating roll 66.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pressing device for a fixing device, a fixing device, and an image forming apparatus.

  As a fixing device, for example, in Patent Document 1 below, a fixing roller that has an elastic layer and rotates with a heating unit, an endless fixing belt that rotates by being driven by the fixing roller, and the fixing belt are provided. A pressing unit that presses from the inner peripheral surface side, presses the fixing belt against the fixing roller, and forms a nip portion for fixing a toner image on the recording material between the fixing belt and the fixing roller; The pressing means is composed of a plurality of pressing members disposed in the recording material conveying direction, and the plurality of pressing members are formed of an elastic member and an elastic member formed at a higher pressure than the elastic member. A fixing device including a high-pressure member that presses the fixing belt against the fixing roller and a separation member is disclosed.

  Further, in Patent Document 2 below, a fixing roll that has an elastic layer on the outer peripheral surface and is driven to rotate in a heated state, and a part of the fixing roll is in contact with the peripheral surface of the fixing roll and is supported so as to be able to move around. An endless belt, a pressure pad that is disposed along the axial direction of the fixing roll, presses the endless belt against the fixing roll from the inside of the endless belt, and a support that supports the pressure pad. The support member is supported near both ends of the pressure pad in the axial direction of the member and the fixing roll, and one end of the endless belt in the circumferential movement direction is supported to be rotatable, and the other end is supported via an elastic member. A pressure lever that applies a pressing force of the pressure pad to the fixing roll, and a recording medium having a toner image adhered to a contact portion between the fixing roll and the endless belt Pressure lever is elastic Fixing apparatus is disclosed, wherein the fed from the supported end side via the.

  Further, in Patent Document 3 below, a fixing region is formed by regions that are in pressure contact with each other, a recording sheet that has entered the fixing region is sandwiched, a heating roll that rotates in the recording sheet conveyance direction, an endless pressure belt, and the endless A belt support frame that is disposed inside the pressure belt and extends in the width direction of the pressure belt, a pressing member holder that is supported by the belt support frame, and presses the back surface of the pressure belt toward the heating roll. A fixing pressing member having elasticity; a fixing pressing member support that supports the fixing pressing member and supported by the pressing member holder; and an inner peripheral surface of the pressure belt that is attached to the belt support frame. A belt support member for rotatably supporting the pressure belt, and an elasticity higher than that of the pressing member holding body. Fixing apparatus is disclosed which includes a configured the fixing pressing member support by.

JP 2009-271281 A JP 2008-096738 A JP 2006-251622 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device, a fixing device, and an image forming apparatus for a fixing device that can suppress variation in pressing force as compared with a case where a pressing member having a fixed mounting position is used. .

According to a first aspect of the present invention, there is provided a pressing device for a fixing device.
A first pressure member provided on the outlet side from which the recording medium is discharged;
A second pressure member provided on the inlet side into which the recording medium is inserted;
A support member having a first region to which the first pressure member is fixed and a second region to which the second pressure member is fixed, the first region and the second region And a support member that is formed integrally and supports the second pressure member so as to press the pressed member against the pressed member.

  Further, in the pressing device for a fixing device according to claim 2, the hardness of the first pressure member is higher than the hardness of the second pressure member.

  The fixing device pressing device according to claim 3, wherein the support member includes the first pressure member and the second pressure member between the first region and the second region. It is bent in the direction in which the pressure member approaches.

According to a fourth aspect of the present invention, there is provided a fixing device.
A rotatable heating roll;
An endless belt that travels following the rotation of the heating roll;
A holding member disposed on the opposite side of the heating roll and inside the endless belt;
A first pressure member provided on the outlet side from which the recording medium is discharged, a second pressure member provided on the inlet side into which the recording medium is inserted, and a first pressure member to which the first pressure member is fixed 1 and a second region to which the second pressure member is fixed, wherein the first region and the second region are integrally formed, and the second region And a pressing member that supports the pressing member so as to press the heating roll against the heating roll.

  In the fixing device according to claim 5, the hardness of the first pressure member is higher than the hardness of the second pressure member.

  Further, in the fixing device according to claim 6, the support member is configured such that the first pressure member and the second pressure member are close to each other between the first region and the second region. Bent in the direction.

  In the fixing device according to claim 7, a space is provided between the other side of the support member and the holding member.

  In the fixing device according to claim 8, the deformation amount per unit load of the second pressure member is smaller than the deformation amount per unit load on the second region side of the support member.

Further, in the fixing device according to claim 9, when the first pressure member has a sag and the first pressure member is pressed toward the heating roll,
The second pressure member is disposed at a predetermined position by moving the second region side of the support member to the side opposite to the heating roll side.

Further, in the fixing device according to claim 10, when a sag occurs in the second pressure member,
The second pressure member is arranged at a predetermined position by moving the second region side of the support member to the heating roll side.

  An image forming apparatus according to an eleventh aspect includes the pressing device for the fixing apparatus according to any one of the first to third aspects.

  An image forming apparatus according to a twelfth aspect includes the fixing device according to any one of the fourth to tenth aspects.

  According to the pressing device for the fixing device of the first aspect, it is possible to suppress fluctuations in the pressing force that presses the pressed member, as compared with the case where the pressing member whose attachment position is determined is used.

  According to the pressing device for the fixing device of the second aspect, it is possible to further suppress fluctuations in the pressing force that presses the pressed member.

  According to the pressing device for the fixing device of the third aspect, it is possible to further suppress fluctuations in the pressing force that presses the pressed member.

  According to the fixing device of the fourth aspect, fluctuations in the pressing force of the pressing device toward the heating roll can be suppressed as compared with the case where the pressing member whose mounting position is determined is used.

  According to the fixing device of the fifth aspect, fluctuations in the pressing force of the pressing device toward the heating roll can be further suppressed.

  According to the fixing device of the sixth aspect, fluctuations in the pressing force of the pressing device toward the heating roll can be further suppressed.

  According to the fixing device of the seventh aspect, fluctuations in the pressing force of the pressing device toward the heating roll can be further suppressed.

  According to the fixing device of the eighth aspect, it is possible to further suppress fluctuations in the pressing force of the pressing device toward the heating roll.

  According to the fixing device of the ninth aspect, fluctuations in the pressing force of the pressing device toward the heating roll can be further suppressed.

  According to the fixing device of the tenth aspect, fluctuations in the pressing force of the pressing device toward the heating roll can be further suppressed.

  According to the image forming apparatus of the eleventh aspect, fluctuations in the pressing force of the pressing device toward the heating roll can be suppressed as compared with the case where the pressing member whose attachment position is determined is used.

  According to the image forming apparatus of the twelfth aspect, it is possible to suppress the variation in the pressing force of the pressing device toward the heating roll as compared with the case where the pressing member whose mounting position is determined is used.

1 is a side sectional view showing an image forming apparatus according to an embodiment. FIG. 3 is a side cross-sectional view illustrating the fixing device according to the embodiment. FIG. 3 is a partially enlarged view of the fixing device according to the embodiment illustrated in FIG. 2. It is side surface sectional drawing of the press unit which concerns on embodiment. It is a section perspective view of a pressing device and a holding member concerning an embodiment. It is a perspective view of the press apparatus which concerns on embodiment. 6 is a graph illustrating pressure distribution of the fixing device according to the embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a pressing device, a fixing device, and an image forming apparatus for embodying the technical idea of the present invention, and is not intended to specify the present invention. Rather, it is equally applicable to other embodiments within the scope of the claims.

[Embodiment]
An image forming apparatus 10 according to the embodiment will be described with reference to FIGS. As shown in FIG. 1, the image forming apparatus 10 according to the embodiment includes an image forming apparatus main body 12, and at least one paper feeding unit 18, an image forming unit 14, and the inside of the image forming apparatus main body 12. The image forming apparatus main body 12 is provided with a discharge port 34 and a conveyance path 32 through which a recording medium 128 such as a recording sheet as a transfer material is conveyed is provided so as to communicate with the fixing device 36. It has been. Further, as will be described later, the image forming apparatus 10 according to the embodiment includes a free belt nip fusing (FBNF) in which a pressing device 100 provided in the fixing device 36 includes two pressure members having different hardnesses. )) System configuration. Each configuration will be described below.

  The paper feed unit 18 includes a paper feed unit main body 20, a paper feed cassette 22 that accommodates a recording medium 128 as a transfer material, a pickup roll 24 that pulls out the recording medium 128 loaded on the paper feed cassette 22, and a recording medium 128. A feed roll 28 and a retard roll 26 which are fed while being rolled are disposed. By the rotation of the pickup roll 24, the feed roll 28 and the retard roll 26, the recording medium 128 loaded on the paper feed cassette 22 is conveyed along a conveyance path 32 to a registration roll 38 which will be described later. The paper feed cassette 22 is detachably attached to the paper feed unit main body 20. Further, the number of paper feeding units may be one, or a plurality of paper feeding units may be provided, but in the embodiment, two paper feeding units 18 are provided as shown in FIG.

  The image forming means 14 is of an electrophotographic type, and is charged by the image carrier 44 made of a photosensitive member, a charging device 56 made of, for example, a charging roll that uniformly charges the image carrier 44, and the charging device 56. An optical writing device 58 for writing a latent image on the image carrier 44 with light, a developing device 60 having a developing roll so as to visualize the latent image of the image carrier 44 formed by the optical writing device 58 with toner, A transfer device 42 composed of, for example, a transfer roll for transferring the toner image by the developing device 60 to the recording medium 128, a cleaning device 62 for cleaning the toner remaining on the image carrier 44, and the recording medium transferred by the transfer device 42 And a fixing device 36 for fixing the toner image on the recording medium.

  The optical writing device 58 includes, for example, a scanning laser exposure device, and forms a latent image on the image carrier 44 across a process cartridge 64 described later. The optical writing device 58 may use an LED, a surface emitting laser, or the like as another embodiment.

  In the process cartridge 64, the image carrier 44, the charging device 56, the developing device 60, and the cleaning device 62 are integrated, and these can be replaced as a unit. The process cartridge 64 can be removed from the image forming apparatus main body 12 by opening the discharge unit 16.

  The conveyance path 32 is a path of the recording medium 128 that communicates from the pickup roll 24 of the lower sheet feeding unit 18 to the upper discharge port 34 of the image forming apparatus main body 12. The conveyance path 32 has a portion that is formed in the image forming apparatus main body 12 and is formed substantially vertically from the pickup roll 24 of the lower sheet feeding unit 18 to the fixing device 36.

  A transfer device 42 and an image carrier 44 are disposed on the upstream side of the fixing device 36 in the conveyance path 32, and a resist roll 38 is disposed on the upstream side of the transfer device 42 and the image carrier 44. Further, a discharge roll 40 is disposed in the vicinity of the discharge port 34 of the conveyance path 32.

  Therefore, the recording medium 128 sent out from the paper feed cassette 22 of the paper feed unit 18 by the pickup roll 24 is turned by the retard roll 26 and the feed roll 28 and guided to the transport path 32, and is temporarily stopped by the registration roll 38. The developer image is transferred between the transfer device 42 and the image carrier 44 at a timing, and the transferred developer image is fixed by the fixing device 36, and is discharged from the discharge port 34 by the discharge roller 40. 16 is discharged.

  Next, the fixing device 36 of the embodiment will be described with reference to FIGS. The fixing device 36 according to the embodiment includes a heating roll 66, an endless belt 72 formed in an endless belt shape, a guide member 74 that rotatably guides the endless belt 72, and an endless belt 72 disposed inside the endless belt 72. And a impregnation pad 78 for supplying a lubricant to the inside of the endless belt 72.

  The guide members 74 are disposed at both ends of the endless belt 72 and the pressing unit 76 and are supported by the frames 126 and 127. A sliding sheet (not shown) for reducing friction between the endless belt 72 and the pressing unit 76 may be provided between the endless belt 72 and the pressing unit 76.

  The heating roll 66 has a cylindrical roll portion 84 and a heater 86 disposed in the roll portion 84. The roll part 84 is supported by a bearing for heating rolls (not shown) so as to be rotatable, and rotates in the arrow A direction. The roll portion 84 includes a core 88 made of a metal material such as iron, stainless steel, and aluminum, and a release layer 90 that is coated or applied to the core 88, and has a so-called hard roll having no elastic layer. It has become. The core 88 has an outer shape of, for example, 25 mm and a wall thickness of, for example, 0.7 mm. The release layer 90 is made of an insulating material having excellent release properties, such as PFA, and has a film thickness of, for example, 20 μm.

  A plurality of (for example, five) peeling claws 92 are in contact with the roll portion 84. The heater 86 is composed of, for example, two lamps. A thermostat 94 is provided on the opposite side of the heating roll 66 from the endless belt 72 so as to face the heating roll 66.

  The endless belt 72 is provided between the heating roll 66 and the pressing unit 76 and travels in the direction of arrow C following the rotation of the heating roll 66. When the heating roll 66 and the endless belt 72 are in pressure contact with each other by the pressing unit 76, the pressing portion 102 is formed, and the toner image is fixed on the recording medium 128 by the pressing portion 102. The endless belt 72 is formed of, for example, a synthetic resin such as polyimide into an endless belt shape having a thickness of 75 μm, for example, and a release layer made of PFA or the like is provided on the surface.

  An inlet chute 96 is provided on the upstream side of the pressing portion 102. The recording medium 128 conveyed in the direction of arrow B is guided by the inlet chute 96 so that the tip of the recording medium 128 is guided to the pressing portion 102. An outlet chute 98 is provided on the downstream side of the pressing portion 102.

  The pressing unit 76 includes a pressing device 100 that presses the heating roll 66 via the endless belt 72, a holding member 118 that holds the pressing device 100, and frames 126 and 127 that support the holding member 118 and the guide member 74. The housing 124 supports the rotation of the endless belt 72. At this time, the holding member 118 of the pressing unit 76 and the frames 126 and 127 are supported so as to press the pressing device 100 toward the heating roll 66 side.

  As shown in FIGS. 4 to 6, the pressing device 100 includes a support member 104, a first pressure member 114, and a second pressure member 116, and the first pressure member 114 and the first pressure member 114 Two pressure members 116 are provided adjacent to each other. The side on which the first pressure member 114 is provided is the downstream side 70 in the rotational direction of the heating roll 66 and the endless belt 72, that is, the outlet side 70, and the side on which the second pressure member 116 is provided is An upstream side 68 in the rotation direction of the heating roll 66 and the endless belt 72, that is, an inlet side 68 is provided.

  The support member 104 is a long plate-like body formed of a metal material such as stainless steel, and an intermediate portion that divides an axis along the longitudinal direction into a first region 106 on one side and a second region 108 on the other side. The portion 110 is bent, that is, a so-called “reverse character”.

  The support member 104 is a portion where the first region 106 side on one side is held in contact with the holding member 118, and the second region 108 side on the other side is elastic when the first region 106 is held by the holding member. It is designed to be transformed. In addition, the extended protrusion 112 is formed in the longitudinal direction edge part of the 1st area | region 106 of the support member 104, and the support member 104 can be attached to the holding member 118 by this protrusion 112 now. ing. The attachment of the support member is not limited to the extended protrusion, and other attachment structures can be used.

  The first pressure member 114 is substantially the same length as the length of the support member 104 in the longitudinal direction, and is formed of a heat-resistant material such as silicon rubber, for example. 106 is attached. Similarly to the first pressure member 114, the second pressure member 116 has substantially the same length as the longitudinal direction of the support member 104, and is made of a heat resistant material such as silicon rubber. It is formed and attached to the second region 108 of the support member 104. In addition, although the 1st pressurization member and 2nd pressurization member of embodiment are cross-sectional shapes are rectangular as shown in FIG. 5, it is not restricted to this, A cross-sectional shape has a polygonal shape or a curved surface It can also be a shape.

  Further, the hardness of the first pressure member 114 and the second pressure member 116 is higher in the first pressure member 114 than in the second pressure member 116. That is, the second pressure member is softer than the first pressure member. As the hardness of the first pressure member 114 and the second pressure member 116 at this time, for example, the hardness of the first pressure member 114 is 70 to 75 degrees in Asker C, and the second pressure member 114 has a second hardness. The pressure member 116 has an Asker C hardness of 30 to 35 degrees.

  The holding member 118 is made of, for example, a resin material such as LCP (liquid crystal polymer) having high heat resistance. The holding member 118 is formed with an arrangement portion 120 where the pressing device 100 is arranged at a position facing the heating roll 66. The arrangement portion 120 has a concave shape corresponding to the shape of the support member 104, and when the first region 106 side of the support member 104 is held in contact with the holding member 118, The second region 108 side is prevented from contacting the holding member 118. Therefore, a space 122 is provided between the holding member 118 and the second region 108 side of the support member 104.

  The frames 126 and 127 are made of a metal material such as stainless steel or aluminum, and press the holding member 118 toward the heating roll 66. At this time, the frames 126 and 127 are biased toward the heating roll 66 by biasing means (not shown) such as a coil spring.

  The housing 124 is formed of a synthetic resin such as PET (polyethylene terephthalate), and is supported by the frame 127 and supports the endless belt 72.

  In the fixing device 36 having the above-described configuration, first, the recording medium 128 onto which the toner image is transferred by the image forming unit 14 passes through the conveyance path 32, and the heating roll 66 and the endless belt 72 are pressed by the pressing device 100. It is sent to the pressed portion 102 that has been made. At this time, the heating roll 66 is rotationally driven, and the endless belt 72 is moved around the outer periphery of the pressing unit 76 in accordance with the rotation, whereby the recording medium 128 is fed into the pressing portion. The recording medium 128 that has been fed is sandwiched between the heating roll 66 and the endless belt 72 and pressed by the pressing device 100 of the heating roll 66 and the pressing unit 76, so that the toner image is recorded on the recording medium. 128 is fixed.

  At this time, the pressing by the pressing device 100 is first pressed by the second pressure member 116 having a low hardness provided on the inlet side 68 and then pressed by the first pressure member 114 having a high hardness. The second pressure member 116 is pressed by a low pressing force by using the elastic force of the support member 104, and the first pressure member 114 on the outlet side 70 is a biasing means of the pressing unit 76. It is pressed with high pressing force by the urging force.

With such a configuration, in the fixing device 36 of the embodiment, the elastic force of the first pressure member 114 and the second pressure member 116 as the pressing device 100 of the fixing device 36 is used. Even if the so-called sag occurs, and the initial pressing force cannot be obtained, the fluctuation of the pressure distribution of the pressing force of the pressing portion 102 is suppressed, as shown by the line X shown in FIGS. 7A and 7B. Obtain the pressure distribution.

  That is, as shown in FIG. 7A, when the first pressurizing member 114 on the outlet side 70 is sagged, the first pressurizing member 114 is moved to the heating roll 66 side by the urging force. Even if the second pressing member 116 on the inlet side 68 moves so that the position of the second pressing member 116 bites into the heating roll 66 and the pressing force of the second pressing member increases as shown by the line Y, The pressing force of the second pressurizing member 116 is increased by the support member 104 on the second region 108 side to which the second pressurizing member 116 is attached moving to the side opposite to the heating roll 66 side. Suppress.

  Further, as shown in FIG. 7B, when the second pressurizing member 116 on the inlet side 68 has a sag, it is assumed that the pressing force of the second pressurizing member 116 becomes weak as indicated by the line Z. However, the second pressing member 116 moves to the heating roll 66 side and is pressed to the heating roll 66 side by the elastic force of the support member 104 on the second region 108 side to which the second pressing member 116 is attached. This suppresses the pressing force of the second pressure member 116 from being lowered.

DESCRIPTION OF SYMBOLS 10: Image forming apparatus 12: Image forming apparatus main body 14: Image forming means 16: Ejection part 18: Paper feeding unit 20: Paper feeding unit main body 22: Paper feeding cassette 24: Pickup roll 26: Retard roll 28: Feed roll 32: Transport path 34: Ejection port 36: Fixing device 38: Registration roll 40: Ejection roll 42: Transfer device 44: Image carrier 56: Charging device 58: Optical writing device 60: Developing device 62: Cleaning device 64: Process cartridge 66: Heating roll 68: Upstream side (inlet side) 70: Downstream side (outlet side) 72: Endless belt 74: Guide member 76: Pressing unit 78: Impregnation pad 84: Roll part 86: Heater 88: Core 90: Release layer 92 : Peeling nails 94: thermostat 96: inlet shoot 8: Outlet chute 100: Pressing device 102: Pressing portion 104: Support member 106: First region 108: Second region 110: Intermediate portion 112: Projection 114: First pressing member 116: Second pressing Member 118: Holding member 120: Arrangement part 122: Space 124: Housing 126: Frame 127: Frame 128: Recording medium

Claims (12)

A first pressure member provided on the outlet side from which the recording medium is discharged;
A second pressure member provided on the inlet side into which the recording medium is inserted;
A support member having a first region to which the first pressure member is fixed and a second region to which the second pressure member is fixed, the first region and the second region A support member that is formed integrally and supports the second pressure member so as to press the pressed member;
A pressing device for a fixing device.   The pressing device for a fixing device according to claim 1, wherein the hardness of the first pressure member is higher than the hardness of the second pressure member.   3. The support member according to claim 1, wherein the support member is bent in a direction in which the first pressure member and the second pressure member approach each other between the first region and the second region. The pressing device for the fixing device according to claim. A rotatable heating roll;
An endless belt that travels following the rotation of the heating roll;
A holding member disposed on the opposite side of the heating roll and inside the endless belt;
A first pressure member provided on the outlet side from which the recording medium is discharged, a second pressure member provided on the inlet side into which the recording medium is inserted, and a first pressure member to which the first pressure member is fixed 1 and a second region to which the second pressure member is fixed, wherein the first region and the second region are integrally formed, and the second region A pressing device having a supporting member for supporting the pressing member so as to press the heating roll;
A fixing device.   The fixing device according to claim 4, wherein the hardness of the first pressure member is higher than the hardness of the second pressure member.   The said support member is bent in the direction in which the said 1st pressurization member and the said 2nd pressurization member approach between the said 1st area | region and the said 2nd area | region. The fixing device described.   The fixing device according to claim 4, wherein a space is provided between the second region side of the support member and the holding member.   The fixing device according to claim 4, wherein a deformation amount per unit load of the second pressure member is smaller than a deformation amount per unit load on the second region side of the support member. When sag occurs in the first pressure member and the first pressure member is pressed toward the heating roll,
The said 2nd pressurization member is arrange | positioned in a predetermined position, when the said 2nd area | region side of the said support member is moved to the opposite side to the said heating roll side. The fixing device described. When a sag occurs in the second pressure member,
The fixing device according to claim 4, wherein the second pressure member is disposed at a predetermined position by moving the second region side of the support member to the heating roll side. .   An image forming apparatus having the pressing device for a fixing device according to claim 1.   An image forming apparatus comprising the fixing device according to claim 4.

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