JP2014132371A - Fixing device and manufacturing method of nip member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a heat transfer area without increasing the volume of a nip member.SOLUTION: A fixing device 100 comprises: a cylindrical fixing film 110; a heating element (a halogen lamp 120) which is disposed on the inner side of the fixing film 110; a nip member (a nip plate 130) which is disposed so as to slide with an inner surface of the fixing film 110 and receives radiation heat from the heating element; and a backup member (a pressurizing roller 150) which sandwiches the fixing film 110 with the nip member to form a nip portion between the backup member and the fixing film 110. On the heating element side of the nip member, a plurality of recessed portions 131B formed by shaving is provided.

Description

  The present invention relates to a fixing device that thermally fixes a developer image transferred to a recording sheet using a nip member, and a method for manufacturing the nip member provided in the fixing device.

  As a fixing device used in an electrophotographic image forming apparatus, a nip plate that forms a nip portion between a cylindrical fixing film, a heater disposed in the fixing film, and a pressure roller via the fixing film (For example, refer to Patent Document 1). In this technique, the heat from the heater can be efficiently absorbed by the nip plate by forming a plurality of irregularities on the surface of the nip plate on the heater side by press working using a mold. .

JP 2007-121469 A

  However, in press working using a mold as in the above-described technique, fine irregularities cannot be formed, and there is a limit to increasing the heat transfer area for receiving radiation from the heater. Further, when the unevenness is formed to increase the heat transfer area, the volume of the nip plate itself increases, and it is difficult to quickly warm the nip plate.

  Therefore, an object of the present invention is to increase the heat transfer area without increasing the volume of the nip plate (nip member).

  In order to solve the above-described problem, a fixing device according to the present invention includes a cylindrical fixing film, a heating element disposed inside the fixing film, and a sliding contact with an inner surface of the fixing film. A fixing device comprising: a nip member that receives radiant heat from a body; and a backup member that forms a nip portion with the fixing film by sandwiching the fixing film between the nip member and the nip member. A plurality of recesses formed by shaving are provided on the heating element side of the member.

  Moreover, the manufacturing method of the nip member according to the present invention is characterized in that a plurality of recesses are formed on the heating element side of the nip member by shaving.

  According to the present invention, by forming irregularities on the nip member by shaving, for example, irregularities finer than the irregularities formed by press working can be formed, so heat transfer can be performed without increasing the volume of the nip member. The area can be increased.

  According to the present invention, the heat transfer area can be increased without increasing the volume of the nip member.

1 is a diagram illustrating a schematic configuration of a laser printer including a fixing device according to an embodiment of the present invention. 1A is a diagram illustrating a schematic configuration of a fixing device according to an embodiment of the present invention, and FIG. It is a perspective view of a halogen lamp, a nip plate, a reflecting plate, and a stay. It is the figure which looked at the nip plate, the reflecting plate, and the stay from the conveyance direction. It is figure (a)-(c) which shows the manufacturing method of a nip board. It is figure (a)-(c) which shows the modification of the manufacturing method of a nip board. It is explanatory drawing which shows the example which varied the density of the recessed part per unit area in a paper width direction.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the schematic configuration of the laser printer 1 (image forming apparatus) including the fixing device 100 according to the embodiment of the present invention will be described first, and then the detailed configuration of the fixing device 100 will be described.

<Schematic configuration of laser printer>
As shown in FIG. 1, the laser printer 1 includes a main body housing 2 in which a paper sheet 3 as an example of a recording sheet is fed, an exposure device 4, and a toner image (developer) on the paper P. And the fixing device 100 for thermally fixing the toner image on the paper P.

  In the following description, the direction will be described with reference to the user who uses the laser printer. That is, the right side in FIG. 1 is “front”, the left side is “rear”, the front side is “left”, and the back side is “right”. Also, the vertical direction in FIG.

  The paper feed unit 3 is provided in the lower part of the main body housing 2, and includes a paper feed tray 31 that accommodates the paper P, a paper pressing plate 32 that lifts the front side of the paper P, a paper feed roller 33, and a paper feed pad 34. And paper dust removing rollers 35 and 36 and a registration roller 37 are mainly provided. The paper P in the paper feed tray 31 is brought close to the paper feed roller 33 by the paper pressing plate 32 and separated one by one by the paper feed roller 33 and the paper feed pad 34, and the paper dust removing rollers 35, 36 and the registration roller 37. Then, it is conveyed toward the process cartridge 5.

  The exposure apparatus 4 is arranged at the upper part in the main body housing 2 and mainly includes a laser light emitting unit (not shown), a polygon mirror 41 that is rotationally driven, lenses 42 and 43, and reflecting mirrors 44, 45, and 46. In preparation. In the exposure apparatus 4, the laser light (see the chain line) based on the image data emitted from the laser light emitting part is reflected or passed through the polygon mirror 41, the lens 42, the reflecting mirrors 44 and 45, the lens 43 and the reflecting mirror 46 in this order. The surface of the photosensitive drum 61 is scanned at high speed.

  The process cartridge 5 is disposed below the exposure apparatus 4 and is detachably mounted on the main body housing 2 through an opening formed when the front cover 21 provided on the main body housing 2 is opened. Yes. The process cartridge 5 includes a drum unit 6 and a developing unit 7.

  The drum unit 6 mainly includes a photosensitive drum 61, a charger 62, and a transfer roller 63. The developing unit 7 can be attached to and detached from the drum unit 6, and includes a developing roller 71, a supply roller 72, a layer thickness regulating blade 73, and a toner storage portion 74 that stores toner (developer). Mainly prepared.

In the process cartridge 5, the surface of the photosensitive drum 61 is uniformly charged by the charger 62 and then exposed by high-speed scanning of the laser light from the exposure device 4, whereby image data is transferred onto the photosensitive drum 61. An electrostatic latent image based on is formed. Further, the toner in the toner container 74 is supplied to the developing roller 71 via the supply roller 72 and enters between the developing roller 71 and the layer thickness regulating blade 73 to form a thin layer of a certain thickness on the developing roller 71. It is carried on.

  The toner carried on the developing roller 71 is supplied from the developing roller 71 to the electrostatic latent image formed on the photosensitive drum 61. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 61. Thereafter, the paper P is conveyed between the photosensitive drum 61 and the transfer roller 63, whereby the toner image on the photosensitive drum 61 is transferred onto the paper P.

  The fixing device 100 is provided behind the process cartridge 5. The toner image (toner) transferred onto the paper P is thermally fixed onto the paper P by passing through the fixing device 100. The paper P on which the toner image is thermally fixed is discharged onto the paper discharge tray 22 by the transport rollers 23 and 24.

<Detailed configuration of fixing device>
As shown in FIG. 2A, the fixing device 100 includes a fixing film 110, a halogen lamp 120 as an example of a heating element, a nip plate 130 as an example of a nip member, a reflection plate 140, and a backup member. As an example, a pressure roller 150 and a stay 160 are provided.

  The fixing film 110 is an endless (cylindrical) film having heat resistance and flexibility, and both ends of the fixing film 110 are guided by a guide member (not shown). The fixing film 110 is in sliding contact with the nip plate 130 via grease. Depending on the material of the fixing film and the nip plate, the grease may not necessarily be applied.

  The halogen lamp 120 is a known heating element that heats the toner on the paper P by heating the nip plate 130 and the fixing film 110. Inside the fixing film 110, a predetermined amount of heat is supplied from the inner surfaces of the fixing film 110 and the nip plate 130. They are arranged at intervals.

  The nip plate 130 is a plate-like member that receives radiant heat from the halogen lamp 120, and is disposed so as to be in sliding contact with the inner surface of the cylindrical fixing film 110. The nip plate 130 transmits the radiant heat received from the halogen lamp 120 to the toner on the paper P through the fixing film 110.

  The nip plate 130 has a thermal conductivity higher than that of a steel stay 160, which will be described later. For example, the nip plate 130 is formed by bending an aluminum plate or the like into a substantially U shape in sectional view. More specifically, the nip plate 130 is bent toward the base portion 131 extending in the front-rear direction (the conveyance direction of the paper P) and upward (the direction from the pressure roller 150 toward the nip plate 130) in a cross-sectional view. The bent portion 132 is mainly included.

  On the inner surface 131A (the surface on the halogen lamp 120 side) of the base portion 131, a plurality of fine concave portions 131B are formed by shaving. In the drawing, the size of the recess 131B is exaggerated for convenience.

  Specifically, the plurality of recesses 131 </ b> B are formed in a range on the inner side of a contact portion between a reflector 140 and a base portion 131 described later. Thereby, the surface area of the inner surface 131A (including the inner surface of each recess 131B) of the base portion 131 is increased, so that the nip plate 130 can efficiently absorb the radiant heat from the halogen lamp 120.

Here, as the shaving process, a cutting process or a roughing process using an abrasive member can be cited. In the present embodiment, a roughing process is employed. As the polishing member, for example, a paper file, a metal file, a grinder may be employed. Further, as the cutting process, a process of scratching the surface of the nip plate with a cutting tool may be employed.

  Further, the inner surface 131A (including the inner surface of each recess 131B) of the base portion 131 is covered with a heat absorption layer 200 formed by black coating or the like, as shown in FIG. Thereby, the radiant heat from the halogen lamp 120 can be efficiently absorbed by the nip plate 130.

  And the depth of each recessed part 131B is formed so that it may become larger than the thickness of the heat absorption layer 200. FIG. Thereby, since the recess 131B is not filled with the coating of the heat absorption layer 200, the unevenness of the heat absorption layer 200 can be reliably formed on the inner surface 131A of the nip plate 130.

  As shown in FIG. 3, the nip plate 130 further includes an insertion portion 133 that extends in a flat plate shape from the right end portion of the base portion 131, and an engagement portion 134 that is formed at the left end portion of the base portion 131. The engaging portion 134 is formed in a U shape in a side view, and an engaging hole 134B is provided in a side wall portion 134A formed by bending upward.

  As shown in FIG. 2A, the reflection plate 140 applies radiant heat from the halogen lamp 120 (radiant heat radiated mainly in the front-rear direction or upward direction) to the nip plate 130 (the inner surface 131A of the base portion 131). It is a member that reflects toward the outside, and is disposed at a predetermined interval from the halogen lamp 120 so as to surround the halogen lamp 120 inside the fixing film 110.

  By collecting the radiant heat from the halogen lamp 120 to the nip plate 130 with such a reflector 140, the radiant heat from the halogen lamp 120 can be used efficiently, and the nip plate 130 and the fixing film 110 can be heated quickly. Can do.

  The reflection plate 140 is formed by curving an aluminum plate or the like in a substantially U shape in cross section, for example, having a high infrared and far infrared reflectance. More specifically, the reflecting plate 140 mainly includes a reflecting portion 141 having a curved shape (substantially U-shaped in cross section) and a flange portion 142 extending from both ends of the reflecting portion 141 along the outer side in the front-rear direction. . In order to increase the thermal reflectance, the reflection plate 140 may be formed using a mirror-finished aluminum plate or the like.

  As shown in FIG. 3, a total of four flange-like locking portions 143 are formed at both ends of the reflector 140 in the left-right direction (the width direction of the paper P) (only three are shown). The locking portion 143 is located above the flange portion 142. As shown in FIG. 4, when the nip plate 130, the reflecting plate 140, and the stay 160 are assembled, a plurality of contact portions 163 of the stay 160 described later are provided. It arrange | positions so that it may pinch | interpose (adjacent to the outermost contact part 163A in the left-right direction).

  As a result, even if the reflection plate 140 tries to move left and right due to vibrations when the fixing device 100 is driven, the position of the reflection plate 140 in the left-right direction is restricted by the locking portion 143 coming into contact with the contact portion 163A. The As a result, it is possible to suppress the displacement of the reflecting plate 140 in the left-right direction.

  As shown in FIG. 2A, the pressure roller 150 is an elastically deformable member and is disposed below the nip plate 130. The pressure roller 150 forms a nip portion with the fixing film 110 by sandwiching the fixing film 110 with the nip plate 130 in an elastically deformed state.

  The pressure roller 150 is configured to be driven to rotate by a driving force transmitted from a motor (not shown) provided in the main body housing 2, and to rotate with the fixing film 110 (or paper P). The fixing film 110 is driven and rotated by the frictional force.

  The sheet P on which the toner image is transferred is conveyed between the pressure roller 150 and the heated fixing film 110 (nip portion), whereby the toner image (toner) is thermally fixed.

  The stay 160 is a member that ensures the rigidity of the nip plate 130 by supporting both end portions 131C of the nip plate 130 (base portion 131) in the front-rear direction via the flange portion 142 of the reflection plate 140. The stay 160 has a shape (substantially U shape in cross section) along the outer surface shape of the reflecting plate 140 (reflecting portion 141) and is disposed so as to cover the reflecting plate 140. Such a stay 160 has relatively high rigidity, for example, is formed by bending a steel plate or the like into a substantially U shape in cross-sectional view.

  At the lower ends of the front wall 161 and the rear wall 162 of the stay 160, as shown in FIG. 3, a plurality of contact portions 163 formed in a substantially comb shape are provided.

  Further, a substantially L-shaped locking portion 165 extending downward and further toward the left is provided at the right end portions of the front wall 161 and the rear wall 162 of the stay 160. Further, a holding portion 167 is provided at the left end of the stay 160 and extends leftward from the upper wall 166 and is bent into a substantially U shape in a side view. Engagement bosses 167B (only one is shown) projecting inward are provided on the inner surfaces of the side wall portions 167A of the holding portion 167.

  As shown in FIGS. 2 and 3, a total of four abutting bosses 168 projecting inward are provided at both ends in the left-right direction of the inner surfaces of the front wall 161 and the rear wall 162 of the stay 160. The abutting boss 168 abuts on the reflecting plate 140 (reflecting portion 141) in the front-rear direction. As a result, even if the reflection plate 140 tries to move back and forth due to vibrations when the fixing device 100 is driven, the position of the reflection plate 140 in the front-rear direction is restricted by contacting the contact boss 168. As a result, it is possible to suppress the displacement of the reflector plate 140 in the front-rear direction.

  Further, supported portions 169 projecting outward in the left-right direction are formed at the upper portions of the left and right ends of the stay 160, and the supported portions 169 are supported by guide members (not shown).

  When the reflecting plate 140 and the nip plate 130 are assembled to the stay 160 described above, the reflecting plate 140 is first attached to the stay 160 so as to be fitted. Since the abutting boss 168 is provided on the inner surfaces of the front wall 161 and the rear wall 162 of the stay 160, the reflecting plate 140 is temporarily held by the stay 160 when the abutting boss 168 contacts the reflecting plate 140. The

  After that, as shown in FIG. 4, the insertion portion 133 of the nip plate 130 is inserted between the locking portions 165 of the stay 160 to engage the base portion 131 (both end portions 131 </ b> C) with the locking portions 165. Then, the engaging portion 134 (engaging hole 134B) of the nip plate 130 and the holding portion 167 (engaging boss 167B) of the stay 160 are engaged.

  Thus, the nip plate 130 is held by the stay 160 by supporting both end portions 131 </ b> C of the base portion 131 by the locking portion 165 and holding the engaging portion 134 by the holding portion 167. In addition, the reflecting plate 140 is held by the stay 160 in a state where the flange portion 142 is sandwiched between the nip plate 130 and the stay 160.

As a result, even if the reflection plate 140 tries to move up and down due to vibrations when the fixing device 100 is driven, the flange portion 142 is sandwiched between the nip plate 130 and the stay 160 so that the reflection plate 140 is moved in the vertical direction. The position of is regulated. As a result, it is possible to suppress the positional deviation of the reflecting plate 140 in the vertical direction, and to fix the position of the reflecting plate 140 with respect to the nip plate 130.

Next, a method for manufacturing the nip plate 130 will be described.
As shown in FIGS. 5A and 5B, first, on the inner surface 131A (surface on the heating element side) of the base portion 131 of the nip plate 130 (the nip plate 130 cut and bent into a shape as shown in FIG. 3), A plurality of recesses 131B are formed by roughening. Thereafter, as shown in FIG. 5C, the heat absorption layer 200 having a thickness smaller than the depth of the recess 131B is coated on the inner surface 131A of the base 131 including the inner surface of the recess 131B. Thus, the nip plate 130 in which the uneven heat absorbing layer 200 is formed on the inner surface 131A is manufactured.

  Here, in this embodiment, the recess 131B and the like are formed on the inner surface 131A of the base portion 131 of the nip plate 130 formed by cutting and bending into a shape as shown in FIG. 3, but the present invention is not limited to this. Absent. That is, after forming the plurality of recesses 131B and the heat absorption layer 200 at a position corresponding to the base portion 131 of the simple plate material before being formed into the shape as shown in FIG. 3, it is cut and bent into the shape as shown in FIG. Thus, the nip plate 130 may be manufactured.

  Further, after forming a plurality of recesses 131B and the like on the entire surface of a plate material (a plate material having a size capable of cutting a plurality of nip plates 130), the nip plate 130 is cut and bent into a shape as shown in FIG. May be manufactured. In this case, since the concave portion 131B and the like are formed collectively on the surface of the plate material corresponding to a plurality of nip plates, the roughening process and the step of forming the heat absorption layer 200 can be performed collectively and the manufacturing speed is increased. be able to.

According to the above, the following effects can be obtained in the present embodiment.
By forming irregularities on the nip plate 130 by shaving, for example, irregularities finer than the irregularities formed by pressing can be formed, so the heat transfer area can be increased without increasing the volume of the nip plate. Can do. In addition, the manufacturing cost can be reduced as compared with other manufacturing methods such as press working.

  By covering the heat absorption layer 200 having a thickness smaller than the depth of the recess 131B, the shape of the recess 131B is reflected well in the covered heat absorption layer 200, so that the nip plate 130 can absorb the radiant heat more efficiently. Can do.

  Since the recess 131B is formed by the roughing process, the recess 131B finer than the cutting process can be formed.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above embodiment, the heat absorption layer 200 is covered after forming the recess 131B in the nip plate 130, but the present invention is not limited to this. For example, as shown in FIGS. 6A and 6B, after the heat absorption layer 210 is coated on the inner surface 131A of the base portion 131, the heat absorption layer 210 is shaved as shown in FIG. 6C. Accordingly, the recess 210B may be formed.

  Even in this case, the radiant heat can be efficiently absorbed by the recesses 210 </ b> B formed in the heat absorption layer 210.

  The material of the heat absorption layers 200 and 210 is preferably a silicone resin paint, for example.

  Further, the density of the plurality of recesses 131B per unit area in the nip plate 130 may be substantially uniform, but as shown in FIG. 7, the surface roughness of both end portions 330A in the sheet width direction of the nip plate 330 is A plurality of concave portions may be formed at different densities at both end portions 330A and the central portion 330B so as to be finer than the central portion 330B. According to this, since the surface area per unit area of the both end portions 330A of the nip plate 330 is larger than that of the central portion 330B, the heat absorption rate at the both end portions 330A of the nip plate 330 that easily dissipates heat can be increased. It is possible to suppress temperature unevenness in the sheet width direction of the plate 330.

In the above-described embodiment, the reflecting plate 140 and the stay 160 are provided. However, the present invention is not limited to this, and the reflecting plate and the stay may be omitted.
In the embodiment, the halogen lamp 120 (halogen heater) is exemplified as the heating element. However, the present invention is not limited to this, and may be, for example, an infrared heater or a carbon heater.

  In the embodiment, the plate-shaped nip plate 130 is exemplified as the nip member. However, the present invention is not limited to this, and a thick member that is not plate-shaped may be employed.

  In the embodiment, the pressure roller 150 is exemplified as the backup member. However, the present invention is not limited to this, and may be, for example, a belt-like pressure member. In order to form the nip portion, the backup member may be pressed toward the nip member by a biasing member such as a spring, or the nip member may be pressed toward the backup member by a biasing member such as a spring. Also good.

  In the embodiment, the paper P such as plain paper or postcard is exemplified as the recording sheet, but the present invention is not limited to this, and may be, for example, an OHP sheet.

  In the above-described embodiment, the laser printer 1 is exemplified as the image forming apparatus including the fixing device according to the present invention. However, the image forming apparatus is not limited to this. For example, an LED printer that performs exposure using LEDs may be used. It may be a copying machine or a multifunction machine other than the above. In the above-described embodiment, an image forming apparatus that forms a monochrome image is exemplified. However, the present invention is not limited to this, and an image forming apparatus that forms a color image may be used.

DESCRIPTION OF SYMBOLS 100 Fixing device 110 Fixing film 120 Halogen lamp 130 Nip plate 131 Base part 131A Inner surface 131B Concave 150 Pressure roller 200 Heat absorption layer

Claims (12)

A cylindrical fixing film;
A heating element disposed inside the fixing film;
A nip member disposed so as to be in sliding contact with the inner surface of the fixing film and receiving radiant heat from the heating element;
A fixing device comprising a backup member that forms a nip portion with the fixing film by sandwiching the fixing film with the nip member;
The fixing device according to claim 1, wherein a plurality of recesses formed by shaving are provided on the heating element side of the nip member. The recess is covered with a heat absorption layer,
The fixing device according to claim 1, wherein a depth of the concave portion is larger than a thickness of the heat absorption layer. A heat absorption layer is coated on the surface of the nip member on the heating element side,
The fixing device according to claim 1, wherein the concave portion is formed by cutting the heat absorption layer. By forming the plurality of recesses at different densities on both end sides and the center side so that the surface roughness of both ends in the width direction of the recording sheet of the nip member is finer than the center side,
The fixing device according to any one of claims 1 to 3, wherein a surface area per unit area is larger at both ends of the nip member than at a center side.   The fixing device according to claim 1, wherein the shaving process is a roughing process using a polishing member.   The fixing device according to claim 1, wherein the shaving process is a cutting process. A method for manufacturing a nip member that receives radiant heat from a heating element and thermally fixes a developer to a recording sheet,
A method of manufacturing a nip member, wherein a plurality of recesses are formed on the heating element side of the nip member by shaving.   The nip member manufacturing method according to claim 7, wherein the concave portion is covered with a heat absorption layer having a thickness smaller than the depth of the concave portion. A method for manufacturing a nip member that receives radiant heat from a heating element and thermally fixes a developer to a recording sheet,
A heat absorption layer is coated on the surface of the nip member on the heating element side,
A method of manufacturing a nip member, wherein a plurality of recesses are formed by shaving the heat absorption layer.   The plurality of recesses are formed at different densities on both ends and the center so that the surface roughness of both ends in the width direction of the recording sheet of the nip member is finer than that on the center. The manufacturing method of the nip member of any one of Claims 7-9.   The method for manufacturing a nip member according to any one of claims 7 to 10, wherein the shaving process is a roughing process using an abrasive member. The nip member manufacturing method according to any one of claims 7 to 10, wherein the shaving is a cutting process.

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