JP2017053973A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can suppress an increase in force to be applied to the ends in the width direction of a recording medium to be conveyed compared with a case where a leaf spring is supported with an equal force over the axial direction.SOLUTION: A supporting surface 72A is in contact with a part of a leaf spring 80 that applies pressure to a portion held with a portion J1 to support the leaf spring 80. A part of the leaf spring 80 that applies pressure to the portion J1 is in a cantilever state. This configuration suppresses an increase in force to be applied to the ends in the width direction of a recording medium to be conveyed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus.

  The fixing device described in Patent Document 1 includes a heating roll and a pressure belt. The pressure belt includes an endless belt body and a leaf spring having a U-shaped cross section that is disposed inside the belt body and pressurizes the belt body toward the heating roll.

JP 2012-208308 A

  The problem of the present invention is that the force applied to the end portion in the width direction of the recording medium to be conveyed becomes stronger compared to the case where the leaf spring is supported by the same force in the axial direction. It is to suppress.

  An image forming apparatus according to a first aspect of the present invention includes a transport unit that transports a recording medium along a predetermined transport path, a forming unit that forms an image on the transported recording medium, and a rotating rotator. An endless endless member that contacts the rotating body on the outer peripheral surface, conveys the recording medium and fixes the image on the recording medium, and extends in the axial direction of the rotating body inside the endless member, and is elastic A plate spring that deforms and presses the recording medium against the rotating body via the endless member, and the plate that presses the end in the width direction of the recording medium and a portion outside the end within the endless member A support member for supporting the leaf spring so that a force for supporting the spring portion is weaker than a force for supporting the leaf spring portion that pressurizes other portions of the recording medium. And

  An image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, wherein the support member is provided with a support surface that supports the leaf spring, and the support surface is formed of a recording medium. The portion of the leaf spring that supports the portion of the leaf spring that pressurizes the other portion and pressurizes the outside portion including the end in the width direction of the recording medium is in a cantilever state.

  According to the image forming apparatus of the first aspect of the present invention, compared to the case where the leaf spring is supported by the same force in the axial direction, the load is applied to the end portion in the width direction of the recording medium to be conveyed. It is possible to suppress the force that is increased.

  According to the image forming apparatus of the second aspect of the present invention, the recording medium is conveyed as compared with the case where the end portion in the width direction of the recording medium and the portion of the leaf spring that pressurizes the portion outside the end portion are supported. It is possible to suppress the force applied to the end in the width direction of the recording medium from becoming strong.

(A) (B) It is sectional drawing which showed the leaf | plate spring, pressurization belt, heating member, support part, etc. of the fixing device which concerns on embodiment of this invention. 3 is a view showing a leaf spring, a pressure belt, a support portion, and the like of the fixing device according to the embodiment of the present invention. 1 is a cross-sectional view illustrating a fixing device according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a fixing device according to an embodiment of the present invention. It is the perspective view which showed the leaf | plate spring used for the fixing device which concerns on embodiment of this invention. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. (A) (B) It is sectional drawing which showed the leaf | plate spring, pressurization belt, heating member, support part, etc. of the fixing device which concern on the comparison form with respect to embodiment of this invention.

  An example of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. In the drawing, an arrow H indicates the vertical direction of the apparatus (vertical direction), an arrow W indicates the apparatus width direction (horizontal direction), and an arrow D indicates the depth direction of the apparatus (horizontal direction).

(overall structure)
As shown in FIG. 6, in the image forming apparatus 10 according to the present embodiment, a storage unit that stores a sheet member P as a recording medium from the lower side to the upper side in the vertical direction (arrow H direction). 14, a conveying unit 16 that conveys the sheet member P accommodated in the accommodating unit 14, and an image forming unit 20 that performs image formation on the sheet member P conveyed by the conveying unit 16 from the accommodating unit 14 in this order. Is provided.

[Container]
The accommodating portion 14 includes an accommodating member 26 that can be pulled out from the apparatus main body 10 </ b> A of the image forming apparatus 10 to the near side in the apparatus depth direction, and the sheet member P is stacked on the accommodating member 26. Further, the accommodating portion 14 is provided with a delivery roll 30 that sends out the sheet member P stacked on the accommodating member 26 to a conveying path 28 that constitutes the conveying portion 16.

[Transport section]
The transport unit 16 includes a plurality of transport rolls 32 that transport the sheet member P along a predetermined transport path 28.

(Image forming part)
The image forming unit 20 includes four image forming units 18Y, 18M, 18C, and 18K of yellow (Y), magenta (M), cyan (C), and black (K). In the following description, Y, M, C, and K may be omitted when there is no need to distinguish between Y, M, C, and K. The image forming unit 18 is an example of a forming unit.

  Each color image forming unit 18 includes an image carrier 36, a charging roll 38 that charges the surface of the image carrier 36, and an exposure device 42 that irradiates the charged image carrier 36 with exposure light. . Further, the image forming unit 20 is provided with a developing device 40 that develops the electrostatic latent image formed by exposing the image carrier 36 charged by the exposure device 42 described above and visualizes it as a toner image.

  Further, the image forming unit 20 includes an endless transfer belt 22 that circulates in the direction of arrow A in the figure, and a primary transfer roll 44 that transfers the toner image formed by the image forming unit 18 of each color to the transfer belt 22. Is provided. Further, the image forming unit 20 includes a secondary transfer roll 46 that transfers the toner image on the transfer belt 22 to the sheet member P, and a fixing device 50 that heats and pressurizes the sheet member P to fix the toner image on the sheet member P. And are provided.

  Details of the fixing device 50 will be described later.

(Operation of image forming apparatus)
In the image forming apparatus 10, an image is formed as follows.

  First, the charging rolls 38 for each color to which a voltage is applied come into contact with the surface of the image carrier 36 for each color and uniformly charge the surface of the image carrier 36 at a predetermined potential. Subsequently, based on data input from the outside, the exposure device 42 irradiates the surface of the charged image carrier 36 with exposure light to form an electrostatic latent image.

  Thereby, an electrostatic latent image corresponding to the data is formed on the surface of the image carrier 36 of each color. Further, each color developing device 40 develops the electrostatic latent image and visualizes it as a toner image. Further, the toner image formed on the surface of the image holding member 36 for each color is transferred to the transfer belt 22 by the primary transfer roll 44.

  Therefore, the sheet member P sent from the housing member 26 to the transport path 28 by the sending roll 30 is sent to the transfer position T where the transfer belt 22 and the secondary transfer roll 24 come into contact with each other. At the transfer position T, the sheet member P is conveyed by the transfer belt 22 and the secondary transfer roll 24, whereby the toner image on the surface of the transfer belt 22 is transferred to the sheet member P.

  The toner image transferred to the sheet member P is fixed to the sheet member P by the fixing device 50. Then, the sheet member P on which the toner image is fixed is discharged to the outside of the apparatus main body 10A by the transport roll 32.

(Main part configuration)
Next, the fixing device 50 will be described.

  The fixing device 50 is attachable to and detachable from the apparatus main body 10A, and as shown in FIG. 3, the heating member 52 as an example of a rotating body and the sheet member P conveyed between the heating members 52 are on the heating member 52 side. And a pressurizing member 60 that pressurizes the pressure.

[Heating member]
The heating member 52 includes a cylindrical body 52A having an axial direction that is the depth direction of the apparatus, and a heating element 52B disposed inside the cylindrical body 52A. The heating member 52 is rotated in a direction indicated by an arrow R1 (counterclockwise) in the drawing when a rotational force is transmitted from a motor (not shown).

[Pressure member]
The pressure member 60 is an endless (annular) endless member that extends in the depth direction of the apparatus, and is disposed inside the pressure belt 62 and can rotate the rotation of the pressure belt 62. ) Is supported.

  Further, the support mechanism 64 is attached to the leaf spring 80 extending in the apparatus depth direction (the axial direction of the heating member 52), the L-shaped frame 66, the support member 70 that supports the leaf spring 80, and the frame 66. Felt 68 to be provided.

[Pressure belt]
The pressure belt 62 is made of a resin material, contacts the heating member 52 on the outer peripheral surface, and rotates (circulates) in the direction of the arrow R2 (clockwise) in the drawing following the rotating heating member 52. Yes. The pressure belt 62 is conveyed with the sheet member P sandwiched between the heating member 52 and the pressure belt 62. As a result, the pressure belt 62 and the heating member 52 fix the toner image on the sheet member P.

[Support mechanism: Frame]
The frame 66 is formed by bending a sheet metal member, extends in the apparatus depth direction, and has an L-shaped cross section. The frame 66 includes a long portion 66A extending in the radial direction of the heating member 52 when viewed from the depth direction of the apparatus, and a short portion 66C disposed on the opposite side of the heating member 52 across the long portion 66A. doing.

  Further, both end portions of the frame 66 in the apparatus depth direction are supported by a pair of support members (not shown), and each support member is pressed against the heating member 52 side by the elastic force of an elastic member (not shown).

[Supporting mechanism: Felt]
The felt 68 extends in the depth direction of the apparatus, has a rectangular cross section, and is fixed to the short portion 66C of the frame 66 using a fixing member (not shown). The felt 68 is in contact with the back surface of the pressure belt 62. Further, the felt 68 is soaked with a lubricant such as oil, and the lubricant is applied to the back surface of the pressure belt 62 that rotates (circulates).

[Support mechanism: leaf spring]
The leaf spring 80 is formed by bending a stainless steel plate, extends in the apparatus depth direction, and is disposed on the opposite side of the heating member 52 with the pressure belt 62 interposed therebetween. And the leaf | plate spring 80 does not protrude outside the edge part of the pressurization belt 62 in an apparatus depth direction (refer FIG. 1, FIG. 2). Further, the leaf spring 80 is formed to include a supported portion 82 attached to the support member 70, and a pressing portion 84 to which one end portion (upper end portion) of the supported portion 82 is connected to the base end portion. ing.

  The supported portion 82 is linear when viewed from the depth direction of the apparatus, and is arranged so that one end portion is closer to the heating member 52 than the other end portion (lower end portion). Further, the pressing portion 84 has a curved shape in which the pressure belt 62 side is convex when viewed from the apparatus depth direction.

  Further, as shown in FIG. 5, the leaf spring 80 has a slit 86 that divides a part of the leaf spring 80 into a plurality in the apparatus depth direction, leaving a portion on the tip side of the pressing portion 84. It is formed with.

  In this configuration, the leaf spring 80 causes the sheet member P to be heated to the heating member 52 via the pressure belt 62 as shown in FIG. Pressurized.

  Further, by using the pressure member 60 using the leaf spring 80, the amount of heat taken away from the heating member 52 is reduced as compared with the case where a pressure roll is used.

[Support mechanism: Support member]
The support member 70 is integrally formed of a resin material and extends in the apparatus depth direction. The support member 70 includes a support portion 72 that supports the leaf spring 80, a first overhang portion 74 that is coupled to one end portion (upper end portion in the drawing) of the support portion 72 when viewed from the apparatus depth direction, and a support portion. 72 and a second overhanging portion 76 connected to the other end portion (the lower end portion in the figure).

  The first overhanging portion 74 is formed with a recess 74A that is open on the side opposite to the heating member 52 side. The long member 66 </ b> A of the frame 66 is inserted and fixed in the recess 74 </ b> A, so that the support member 70 is supported by the frame 66. The first overhanging portion 74 projects to the heating member 52 side so that the amount of wrapping of the pressure belt 62 around the heating member 52 increases, and the sheet member P is moved to the heating member 52 side via the pressure belt 62. Pressing. Thereby, the range N1 shown in FIG. 3 is set as the nip range.

  The second overhanging portion 76 protrudes toward the heating member 52 and presses the sheet member P toward the heating member 52 via the pressure belt 62.

  The support portion 72 is disposed on the opposite side of the heating member 52 with the leaf spring 80 interposed therebetween, and the support portion 72 has a support surface 72A that is in surface contact with the supported portion 82 of the leaf spring 80 and supports the leaf spring 80. Is formed.

  1A and 1B are cross-sectional views taken along line S1-S1 of FIG. As shown in FIGS. 1A and 1B, the support surface 72 </ b> A pressurizes the end portion in the width direction of the sheet member P and the pressure belt 62 at a portion outside the end portion (portion J <b> 1 in the drawing). The portion of the leaf spring 80 is not supported (see FIG. 4). The support surface 72A supports the leaf spring 80 in contact with a portion of the leaf spring 80 that pressurizes a portion sandwiched by the portion J1 (the other portion of the sheet member P: the portion J2 in the drawing). And the level | step difference is formed in the both ends side of 72 A of support surfaces.

  And the part of the leaf | plate spring 80 which pressurizes the site | part J1 is made the cantilever state. Here, the size of the sheet member P described above is the maximum size sheet member P on which an image can be formed by the image forming apparatus 10. Further, the distance in the apparatus depth direction (distance D1 in FIG. 1B) between the end portion of the sheet member P and the end portion of the support surface 72A is set to 10 [mm] as an example in the present embodiment.

  In the above configuration, the force that supports the portion of the leaf spring 80 that pressurizes the portion J1 by the support member 70 is weaker than the force that supports the portion of the leaf spring 80 that pressurizes the portion J2 by the support member 70. Yes. In the present embodiment, the concept of “weak” includes a case where there is no supporting force.

(Function)
Next, the operation of the fixing device 50 will be described in comparison with the fixing device 200 according to the comparative embodiment. First, with respect to the configuration of the fixing device 200 according to the comparative example, a portion different from the fixing device 50 will be mainly described. Thereafter, the operation of the fixing device 50 will be described. Note that the operation of the fixing device 200 will be described mainly with respect to differences from the fixing device 50.

  The support surface 212A of the support portion 212 of the fixing device 200 according to the comparative embodiment is in contact with the entire supported portion 82 of the leaf spring 80 over the depth direction of the device, as shown in FIGS. The leaf spring 80 is supported. Thereby, the whole leaf | plate spring 82 is supported by the same force over the apparatus depth direction (axial direction).

  Next, the operation of the fixing device 50 will be described.

  The heating member 52 provided in the fixing device 50 receives a rotational force from a motor (not shown), and rotates in the direction of arrow R1 as shown in FIG.

  Further, the pressure belt 62 rotates (circulates) in the direction of the arrow R <b> 2 following the heating member 52. Then, the sheet member P to which the toner image is transferred is conveyed while being sandwiched between the rotating heating member 52 and the pressure belt 62, so that the toner image transferred to the sheet member P is fixed to the sheet member P. Is done.

  Here, in the fixing device 200, as shown in FIGS. 7A and 7B, the leaf spring 82 is supported by the same force over the depth direction of the device. Thereby, the support surface 212A of the support part 212 also supports the part of the leaf spring 80 that pressurizes the part J1.

  On the other hand, in the fixing device 50, as shown in FIGS. 1A and 1B, the portion of the leaf spring 80 that pressurizes the portion J1 is in a cantilever state.

  Thereby, in the fixing device 50, as compared with the case where the fixing device 200 is used, the force applied to the end portion in the width direction of the conveyed sheet member P is suppressed. Hereinafter, the reason why the strength is suppressed will be described. As shown in FIG. 7B, the sheet member P does not exist in an outer portion (range E1 in the drawing) in the apparatus depth direction with the end portion PE in the width direction of the sheet member P as a boundary. Further, the support surface 212A of the support portion 212 of the fixing device 200 also supports the portion of the leaf spring 80 that pressurizes the portion J1. For this reason, in the range E1, the pressure belt 62 and the leaf spring 89 approach the heating member 52.

  In contrast, as shown in FIGS. 1A and 1B, the support surface 72A of the support portion 72 of the fixing device 50 has a portion of the leaf spring 80 that pressurizes the portion J1 in a cantilever state. Yes. For this reason, in the range E1, it is suppressed that the pressurizing belt 62 and the leaf | plate spring 89 approach the heating member 52. FIG.

  As described above, in the fixing device 50, as compared with the case where the fixing device 200 is used, the force applied to the end in the width direction of the conveyed sheet member P is suppressed.

(Summary)
As described above, in the fixing device 50, as compared with the case where the fixing device 200 is used, the force applied to the end portion in the width direction of the conveyed sheet member P is suppressed.

  Further, since the force applied to the end in the width direction of the conveyed sheet member P is suppressed, the durability of the fixing device 50 is reduced as compared with the case where the fixing device 200 is used. Is suppressed.

  Further, in the image forming apparatus 10, the force applied to the end in the width direction of the conveyed sheet member P is suppressed from increasing, so that the sheet is less than when the fixing device 200 is used. Generation of image rubbing (so-called smudge) in the image formed on the member P is suppressed.

  Further, in the image forming apparatus 10, the force applied to the end in the width direction of the conveyed sheet member P is suppressed from increasing, so that the sheet is less than when the fixing device 200 is used. Generation of wrinkles in the member P is suppressed.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. This will be apparent to those skilled in the art. For example, in the above embodiment, the leaf spring 80 is cantilevered, but the portion of the leaf spring 80 that pressurizes the portion J1 is weaker than the force that supports the portion of the leaf spring 80 that pressurizes the portion J2. It may be supported by. Specifically, the portion of the leaf spring 80 that pressurizes the portion J2 may be supported by a thin plate-like burr protruding from the support surface 72A on both sides.

  Further, in the above embodiment, the pressure belt 62 and the leaf spring 80 are used on the pressure side, but a heating belt and a leaf spring may be used on the heating side.

  In the above embodiment, a plurality of slits 86 are formed in the leaf spring 80, but the slits may not be formed in the leaf spring.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 16 Conveying part 18 Image forming unit (an example of a formation part)
28 Transport path 52 Heating member (an example of a rotating body)
62 Pressure belt (an example of an endless member)
70 support member 72A support surface 80 leaf spring

Claims (2)

A transport unit that transports the recording medium along a predetermined transport path;
A forming unit for forming an image on a recording medium to be conveyed;
A rotating body that rotates;
An endless endless member that contacts the rotating body on the outer peripheral surface, conveys the recording medium, and fixes the image on the recording medium;
A leaf spring that extends in the axial direction of the rotating body inside the endless member, elastically deforms, and pressurizes the recording medium to the rotating body via the endless member;
Inside the endless member, the force that supports the portion of the leaf spring that pressurizes the end portion in the width direction of the recording medium and the portion outside the end portion of the leaf spring presses the other portion of the recording medium. A support member for supporting the leaf spring so as to be weaker than a force for supporting the portion;
An image forming apparatus comprising: A support surface for supporting the leaf spring is formed on the support member,
The support surface supports a portion of the leaf spring that pressurizes the other portion of the recording medium,
The image forming apparatus according to claim 1, wherein a portion of the leaf spring that pressurizes an outer portion including an end portion in a width direction of the recording medium is in a cantilever state.

Images