JP4314510B2 - Heater holding member for fixing device, fixing device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heater holding member for a fixing device, a fixing device, and an image forming apparatus.
[0002]
[Prior art]
As a fixing device of an image forming apparatus, a thermal pressure type having a pair of rotating bodies pressed against each other is well known. This type of fixing device has a cylindrical heating roll, and a heater is disposed in the heating roll. In order to reduce the temperature unevenness of the heating roll, which is generated when the heat of the heating roll is transmitted in the axial direction of the heating roll, the opening of the heating roll is provided by a bearing having a fitting portion and a lid body and holding the heating roll. Is known (see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-5-297441 [0004]
[Problems to be solved by the invention]
However, in the above conventional example, in order to remove the heater, it is necessary to remove the bearing from the heating roll.
[0005]
SUMMARY An advantage of some aspects of the invention is that it provides a heater holding member for a fixing device, a fixing device, and an image forming apparatus that can easily hold a heater and reduce temperature unevenness of a heating roll.
[0006]
In order to achieve the above object, a feature of the present invention is a heater holding member for a fixing device that holds a heater disposed in a heating roll having an opening at at least one end, the shaft of the heating roll. An engagement portion that is detachably engaged with a housing that supports the heating roll in a direction substantially perpendicular to the direction, and the opening of the heating roll in a state where the engagement portion is attached to the housing. A heater holding member for a fixing device having a shielding portion that opposes the opening and shields the opening substantially perpendicular to the axial direction of the heating roll .
[0007]
According to yet a second aspect of the present invention has at least a heating roll having a opening at one end, a heater disposed within the heating roll, and a heater holding member for holding the heater, the The heater holding member shields an engagement portion that is detachably engaged with a housing that supports the roll, and an opening of the heating roll, in a direction substantially perpendicular to the axial direction of the heating roll. e Bei a shielding portion, wherein the heater holding member is to be engaged in the axial direction of the heating roll, the shielding portion is opposed to the opening of the heating roll in the axial direction perpendicular to the direction of the heating roll In the fixing device.
[0008]
Preferably, the heater includes a frame body and a bearing that rotatably supports the heating roll on the frame body, and the heater holding member includes a positioning portion that determines a position of the heater with respect to the frame body.
Moreover, it is preferable that the said positioning part has a fitting part attached so that the said shielding part may shield the opening part of the said heating roll, and the insertion / extraction groove | channel which prevents the incorrect mounting | wearing of the said heater holding member.
[0009]
Moreover, it is preferable that the said heater holding member has a heating roll holding part which hold | maintains the axial direction of the said heating roll.
[0010]
Further, it is preferable that a gear is connected to the heating roll, and the heater holding member has a gear holding portion that holds the axial direction of the gear.
[0011]
Moreover, it is preferable that the said heater holding member has a handle part.
[0012]
Moreover, it is preferable that the heater holding member has an elastic claw and holds the heater by locking the elastic claw to the frame body.
[0013]
Moreover, it is preferable that the said shielding part consists of a heat insulating member.
[0014]
Moreover, it is preferable that the said shielding part consists of a flame-retardant member.
[0015]
Furthermore, a third feature of the present invention resides in an image forming apparatus comprising a fixing device having a heater held by a fixing device heater holding member according to claim 1 .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, an image forming unit 14 is mounted in the image forming apparatus main body 12, and a discharge unit 16 described later is provided on the upper portion of the image forming apparatus main body 12. In addition, for example, two-stage sheet feeding units 18 and 18 are disposed below the image forming apparatus main body 12. Further, a plurality of paper feeding units can be optionally arranged below the image forming apparatus main body 12.
[0017]
Each paper feed unit 18 has a paper feed unit main body 20 and a paper feed cassette 22 in which paper is stored. A pickup roll 24 is disposed in the upper part near the rear end of the paper feed cassette 22, and a retard roll 26 and a feed roll 28 are disposed behind the pickup roll 24.
[0018]
The main conveyance path 32 is a sheet path from the feed roll 28 to the discharge port 34, and the main conveyance path 32 is in the vicinity of the back side (the left side surface in FIG. 1) of the image forming apparatus main body 12, and the lowermost supply path. A portion formed substantially vertically from the paper unit 18 to a fixing device 36 described later is included. A transfer device 42 and an image carrier 44, which will be described later, are disposed on the upstream side of the fixing device 36 in the main transport path 32, and a registration 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 main conveyance path 32.
[0019]
Therefore, the sheet fed from the sheet feeding cassette 22 of the sheet feeding unit 18 by the pickup roll 24 is turned by the cooperation of the retard roll 26 and the feed roll 28, and only the uppermost sheet is guided to the main transport path 32. The developer image is temporarily stopped by the roll 38, and the developer image is transferred between a transfer device 42 and an image carrier 44, which will be described later, and the transferred developer image is fixed by the fixing device 36 and discharged. The paper is discharged from the discharge port 34 to the discharge unit 16 by the roll 40.
[0020]
However, in the case of duplex printing, it is returned to the reverse path. That is, the front side of the discharge roll 40 in the main conveyance path 32 is divided into two forks, a switching device 46 is provided in the divided part, and a reverse path 48 is formed from the divided part to the registration roll 38. . The reversing path 48 is provided with transport rolls 50a to 50c. In the case of double-sided printing, the switching device 46 is switched to the side that opens the reversing path 48 and the discharge roll 40 is in front of the rear end of the sheet. Thus, the discharge roll 40 is reversed, the paper is guided to the reverse path 48, and is discharged from the discharge port 34 to the discharge unit 16 through the registration roll 38, the transfer device 42, the image carrier 44 and the fixing device 36. .
[0021]
The discharge unit 16 includes an inclined portion 52 that is rotatable with respect to the image forming apparatus main body 12. The inclined portion 52 has a lower discharge port portion and is inclined so as to gradually increase in the front direction (right direction in FIG. 1), with the discharge port portion as a lower end and a higher tip as an upper end. The inclined portion 52 is supported by the image forming apparatus main body 12 so as to be rotatable around the lower end. As shown by a two-dot chain line in FIG. 1, when the inclined portion 52 is rotated upward and opened, an opening portion 54 is formed, and a process cartridge 64 described later can be attached and detached through the opening portion 54. .
[0022]
The image forming unit 14 is, for example, of an electrophotographic type, and is charged by an 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 a charging device 56. An optical writing device 58 that writes a latent image on the image carrier 44 with light, a developing device 60 that visualizes the latent image of the image carrier 44 formed by the optical writing device 58 with a developer, and the developing device 60. A transfer device 42 composed of, for example, a transfer roll for transferring the developer image produced by the toner onto the paper, a cleaning device 62 composed of, for example, a blade for cleaning the developer remaining on the image carrier 44, and the paper transferred by the transfer device 42 The image forming apparatus includes a fixing device 36 that fixes a developer image on a sheet. The optical writing device 58 is composed of, for example, a scanning type laser exposure device, and is arranged in the vicinity of the front surface of the image forming apparatus main body 12 in parallel with the paper feeding unit 18 described above, and exposes the image carrier 44 across the developing device 60. . The exposure position of the image carrier 44 is the latent image writing position P.
In this embodiment, a scanning laser exposure apparatus is used as the optical writing device 58. However, an LED, a surface emitting laser, or the like can be used as another embodiment.
[0023]
The process cartridge 64 is obtained by integrating the image carrier 44, the charging device 56, the developing device 60, and the cleaning device 62. The process cartridge 64 is disposed immediately below the inclined portion 52 of the discharge portion 16 and is attached / detached via the opening portion 54 formed when the inclined portion 52 is opened as described above.
[0024]
2 to 4, the configuration of the fixing device 36 is shown. The fixing device 36 is unitized and has a frame body 66, and the frame body 66 is configured by combining a first housing 68 and a second housing 70. That is, the first casing 68 and the second casing 70 are connected via the main body fulcrum 72, and the heating roll 74 is rotatably supported by the first casing 68, and the second casing A pressure roll 76 is rotatably supported on the housing 70. The pressure roll 76 is brought into pressure contact with the heating roll 74 by two elastic bodies 78 and 78 formed of a coil spring or the like, and a nip portion 80 is formed. One end of each of the elastic bodies 78 and 78 is supported by the rotary cams 82 and 82, and the other end is hooked on the first housing 68. The rotating cam 82 is rotatably supported at one end of the bracket 84, and expands and contracts the elastic body 78 by rotating. The other end of the bracket 84 is supported by a fulcrum 86.
[0025]
A heater 88 composed of a lamp is disposed in the heating roll 74 to heat the heating roll 74. The above-described conveyance path 32 is configured in the vertical direction across the nip portion 80, and the sheet is conveyed from the bottom to the top. An inlet chute (conveying guide) 90 made of, for example, a plate-like metal is disposed on the upstream side of the nip portion 80, and outlet side chutes 92 a and 92 b are disposed on the downstream side of the nip portion 80, respectively. The outlet side chutes 92a and 92b are provided on the first casing 68 side and the second casing 70 side, and the outlet side chute 92a on the second casing 70 side rotates upward. Paper is allowed to pass through.
[0026]
A thermostat 94 is provided in the first housing 68 in the vicinity of the heating roll 74, and the thermostat 94 prevents a failure due to overheating of the heating roll 74. Further, a plurality of peeling claws 96 are provided in the first casing 68 in the vicinity of the downstream side of the nip portion 80 in the axial direction of the heating roll 74 (paper width direction). The peeling claw 96 is urged toward the heating roll 74 with a weak force that does not damage the surface of the heating roll 74, the tip of the peeling claw 96 is pressed against the surface of the heating roll 74, and is wound around the heating roll 74. The paper to be removed is peeled off.
[0027]
The heating roll 74 has, for example, a cylindrical core 98 having openings at both ends, and a release layer 100 coated on the surface side of the core 98. The core 98 has an outer diameter of, for example, 25 mm, and a thickness of, for example, 0.5 to 1.5 mm. The material forming the core 98 is, for example, iron or aluminum. The release layer 100 is made of, for example, perfluoroalkoxy (PFA) and has a thickness of, for example, 30 to 100 μm.
[0028]
The pressure roll 76 is made of, for example, a rotating shaft 102 made of stainless steel or iron, and a heat-resistant material made of silicon sponge (Asker C hardness: 40 degrees) having a thickness of, for example, 6 to 8 mm. It has the elastic body layer 104 and the coating layer 106 which covers the surface of this heat-resistant elastic body layer 104. The covering layer 106 is made of, for example, PFA and has a thickness of, for example, 30 to 100 μm.
[0029]
5 to 9, the heating roll 74 and its periphery are shown. Bearings 108 and 108 are attached to the heating roll 74 slightly at both ends, and a gear 110 that transmits driving force to the heating roll 74 is connected to one end. On the other hand, in the vicinity of both ends of the first casing 68 that supports the heating roll 74, a pair of engagement holes 114, 114 for engaging a heater holding member 112 described later, and a fitting groove 116 for fitting the bearing 108. And are provided respectively.
[0030]
A heater 88 is inserted into the heating roll 74, and the bearings 108 and 108 are fitted in the fitting grooves 116 and 116 of the first casing 68, respectively. The fitting groove 116 has, for example, an elastic claw (not shown) so that the bearing 108 can be fixed. Therefore, the heating roll 74 is rotatably supported by the first casing 68 via the bearings 108 and 108. The heater holding member 112 is engaged with substantially both ends of the heater 88, and the heater holding member 112 is engaged with the pair of engagement holes 114, 114, whereby the heater 88 is in the first casing 68. It is fixed to. That is, the heater 88 is fixed to the first housing 68 by the heater holding member 112 from a direction substantially perpendicular to the axial direction of the heater 88.
The gear 110 is meshed with another gear (not shown), and the gear 110 is rotated by the driving force from the other gear. The gear 110 transmits driving force to the heating roll 74, and the pressure roll 76 is driven by the rotation of the heating roll 74.
[0031]
Next, the operation of the above embodiment will be described.
When the image forming signal is sent, the image carrier 44 is uniformly charged by the charging device 56, and the charged image carrier 44 is irradiated with light emitted from the optical writing device 58 based on the image signal. A latent image is formed at the latent image writing position P. Light from the optical writing device 58 passes through the process cartridge 64. The latent image of the image carrier 44 formed by the optical writing device 58 is visualized by the developer of the developing device 60.
[0032]
On the other hand, any one of the paper feeding units 18 is selected by a size signal or the like, and the paper stored in one of the paper feeding cassettes 22 is sent out by a pickup roll 24 and is fed by a retard roll 26 and a feed roll 28. It is guided to the main conveyance path 32, is temporarily stopped by the registration roll 38, and is guided between the transfer device 42 and the image carrier 44 at a timing. When the paper is guided between the transfer device 42 and the image carrier 44, the developer on the image carrier 44 is transferred to the paper by the transfer device 42.
[0033]
The sheet onto which the developer has been transferred is guided to the fixing device 36, and the developer is fixed by the thermal pressure by the heating roll 74 and the pressure roll 76. The sheet on which the developer is fixed is discharged from the discharge port 34 to the discharge unit 16 by the discharge roll 40. However, in the case of double-sided printing, it is returned to the reverse path, and is again discharged from the discharge port 34 to the discharge unit 16 through the registration roll 38, the transfer device 42, the image carrier 44 and the fixing device 36.
[0034]
Next, the heater holding member 112 will be described in detail.
In FIG. 10, the heater holding member 112 is shown. The heater holding member 112 includes a pair of elastic claws 118, 118, a handle part 120, a fitting part 122, a shielding part 124, and an insertion / extraction groove 126. The elastic claws 118, 118 constitute an engaging portion, are provided on the lower left and right sides of the heater holding member 112, and are engaged with the engaging holes 114, 114 of the first housing 68, respectively. The handle portion 120 is formed in a flat plate shape and is provided at a substantially right angle to a shielding portion 124 described later so that an operator can easily grasp the heater holding member 112 from above when detaching the heater holding member 112 from the first housing 68. Is arranged. The fitting portion 122 is provided between the pair of elastic claws 118, 118 and is fitted to the substantially end portion of the heater 88 to hold the heater 88. That is, the pair of elastic claws 118, 118 and the fitting portion 122 constitute a positioning portion that determines the position of the heater 88 with respect to the first housing 68. The shielding part 124 is provided on the back surface of the heater holding member 112 and has a shielding surface substantially perpendicular to the axial direction of the heater 88. The insertion / extraction groove 126 is opened larger than the fitting portion 122 so as to prevent the heater holding member 112 from being attached to the first housing 68 in an incorrect direction. That is, if the heater holding member 112 is to be mounted on the first housing 68 in the wrong direction, the fitting portion 122 abuts on the substantially end portion of the heater 88 and the elastic claw 118 does not engage with the engagement hole 114. It is like that.
[0035]
At least the shielding part 124 of the heater holding member 112 is made of a member having, for example, heat insulation and flame retardancy. Further, the entire heater holding member 112 may be formed of a member having heat insulation and flame retardancy.
The heater holding member 112 is preferably made of, for example, polyetherimide (PEI), which has heat insulation properties, wear resistance of a portion in sliding contact with the gear 110, flexibility in the elastic claw 118, and good moldability. . In addition, the heater holding member 112 may be formed of polyphenylene sulfide (PPS), thermoplastic polyimide (PI), or the like with added flexibility.
[0036]
FIG. 11 shows a state where the heater holding member 112 is mounted on the first housing 68. The heater 88 is inserted into the heating roll 74 and disposed in the first casing 68 together with the heating roll 74. Then, the heater holding member 112 fits the heater 88 in the fitting portion 122 and engages the pair of elastic claws 118 and 118 with the engagement holes 114 and 114 of the first housing 68, respectively. 88 is fixed between the heater holding member 112 and the first casing 68. The operator can easily attach and detach the heater holding member 112 with the handle portion 120.
[0037]
FIG. 12 is a schematic view showing a state in which the heater holding member 112 fixes the heater 88 to the first housing 68.
When the heater holding member 112 is engaged with the first casing 68 in the vicinity of the gear 110, the gear 110 connected to the heating roll 74 is held by the shielding portion 124 in the axial direction of the gear 110. When the heater holding members 112 and 112 are engaged with the first casing 68, one end of the heating roll 74 is held by the shielding portion 124 via the gear 110 in the axial direction of the heating roll 74 and the other end. Is directly held by the shield 124. Further, each shielding part 124 faces the opening provided at both ends of the heating roll 74, and shields the cooling air for cooling the inside of the image forming apparatus 10 toward the opening of the heating roll 74. . Therefore, it is possible to reduce the occurrence of temperature unevenness on the surface of the heating roll 74 due to the cooling air. That is, the shielding part 124 is disposed so as to face the opening of the heating roll 74 by engaging the pair of elastic claws 118 and 118 with the engagement holes 114 and 114, respectively, and shields the cooling air, The axial direction of the heating roll 74 or the gear 110 is held. In addition, since the heater holding member 112 has the insertion / extraction groove 126, the shield part 124 is not mounted so as not to be opposed to the opening of the heating roll 74 by mistake.
[0038]
In FIG. 13, the 1st modification of the heater holding member 112 is shown. In this first modification, the heater holding member 112 is formed to be longer in the axial direction of the heating roll 74, the tip abuts on the frame body 66, and protrudes from the heating roll 74 of the heater 88. It covers the part. In addition, since at least the shielding portion 124 of the heater holding member 112 is flame retardant, even if the heater 88 is ignited, it is possible to prevent the heater holding member 112 from igniting other members.
[0039]
In FIG. 14, the 2nd modification of the heater holding member 112 is shown. This second modification is applied when the fitting portion 122 has a substantially semicircular cross section and the heater 88 has a circular cross section. The fitting part 122 should just be formed according to the shape of the heater 88, and another shape may be sufficient as it.
[0040]
In the above embodiment, the heater holding member 112 shields the opening of the heating roll 74, so that it is possible to reduce the cooling air that cools the inside of the image forming apparatus from flowing into the heating roll 74. It is possible to reduce the occurrence of temperature unevenness. Further, the heater holding member 112 can shield heat between the inside and outside of the heating roll 74 because at least the shielding portion 124 has a heat insulating property.
In addition, since the heater holding member 112 includes the elastic claw 118, it is easy to attach and detach, and since the handle portion 120 is provided, the workability of the work for maintaining the heater 88 can be improved.
The heater holding member 112 fixes the heater 88 and holds the axial direction of at least one of the gear 110 and the heating roll 74. Therefore, in order to maintain the axial direction of the heater 88, the gear 110, and the heating roll 74, there is no need to provide another member for the first casing 68, and the fixing device can be reduced in size and cost. it can.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to easily hold the heater and reduce the temperature unevenness of the heating roll.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a fixing device according to an embodiment of the present invention.
3 is a view showing a side surface in the vicinity of an elastic body of the fixing device shown in FIG. 2. FIG.
4 is a schematic view showing a cross section of the fixing device shown in FIG. 2. FIG.
FIG. 5 is a perspective view showing a heating roll and its surroundings.
FIG. 6 is a top view showing a state in which a heating roll is attached to the first housing.
7 is an enlarged view showing the right side of the top view shown in FIG. 6. FIG.
8 is an enlarged view showing the left side of the top view shown in FIG. 6. FIG.
FIG. 9 is a diagram showing a state in which a heating roll having a heater inserted therein and bearings and gears is attached to the first housing.
FIG. 10 is a view showing an outer shape of a heater holding member.
FIG. 11 is a schematic diagram showing a state in which a heater holding member is mounted on the first housing.
FIG. 12 is a schematic view showing a state in which the heater holding member fixes the heater to the first housing.
FIG. 13 is a view showing a first modification of the heater holding member.
FIG. 14 is a view showing an outer shape of a second modification of the heater holding member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 14 Image carrier forming means 36 Fixing device 66 Frame body 68 First casing 70 Second casing 74 Heating roll 76 Pressing roll 88 Heater 98 Core 100 Release layer 108 Bearing 110 Gear 112 Heater holding member 114 Engagement hole 116 Fitting groove 118 Elastic claw 120 Handle part 122 Fitting part 124 Shielding part 126 Insertion / extraction groove

Claims (11)

A heater holding member for a fixing device that holds a heater arranged in a heating roll having an opening at least at one end,
An engagement portion that is detachably engaged with a casing that supports the heating roll in a direction substantially perpendicular to the axial direction of the heating roll;
With the engagement portion mounted on the housing, a shielding portion that opposes the opening of the heating roll and shields the opening substantially perpendicular to the axial direction of the heating roll;
A heater holding member for a fixing device, comprising: Has at least a heating roll having a opening at one end, a heater disposed within the heating roll, and a heater holding member for holding the heater, and
The heater holding member includes an engaging portion that is detachably engaged with a casing that supports the heating roll in a direction substantially perpendicular to the axial direction of the heating roll, and a shield that shields the opening of the heating roll. Bei example a section, wherein the heater holding member by engaging in the axial direction of the heating roll, said shielding portion is opposed to the opening of the heating roll in the axial direction perpendicular to the direction of the heating roll A fixing device characterized by the above.   A frame body and a bearing that rotatably supports the heating roll on the frame body, and the heater holding member includes a positioning portion that determines a position of the heater with respect to the frame body. Item 3. The fixing device according to Item 2.   The said positioning part has a fitting part attached so that the said shielding part may shield the opening part of the said heating roll, and the insertion / extraction groove | channel which prevents the incorrect mounting | wearing of the said heater holding member. The fixing device described.   The fixing device according to claim 4, wherein the heater holding member includes a heating roll holding unit that holds an axial direction of the heating roll.   The fixing device according to claim 4, wherein a gear is connected to the heating roll, and the heater holding member has a gear holding portion that holds an axial direction of the gear.   The fixing device according to claim 4, wherein the heater holding member has a handle portion.   The fixing device according to claim 4, wherein the heater holding member has an elastic claw, and the elastic claw is engaged with the frame body to hold the heater.   The fixing device according to claim 4, wherein the shielding portion is made of a heat insulating member.   The fixing device according to claim 4, wherein the shielding portion is made of a flame retardant member.   An image forming apparatus comprising a fixing device having a heater held by a fixing device heater holding member according to claim 1.

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