JPH0632516A - Sheet separating device - Google Patents

Abstract

PURPOSE:To decrease toe press-contact force of a separating pawl against a thermal roller, and to increase the resistance force of the separating pawl against wind-up. CONSTITUTION:A sheet separating device comprises a support member 93 located downstream of a fixing and conveying device in a conveying direction and having a support part 96 having a predetermined length in the conveying direction, a sheet-like separating pawl 95 having its proximal end fixed to a part of the support part 96 and its distal end resiliently abutting against the outer surface of a thermal roller 50. The support part 96 has a fixing part 96a to which the proximal end of the separating pawl 95 is fixed, and an extension part 96b having a fulcrum P2, which extends from the fixing part 96a toward the thermal roller 50 so as to oppose the separating pawl 95 with a predetermined gap therebetween in a posture such that the distal end of the pawl 95 abuts against the roller 50 so as to separate a sheet and against which a part of the pawl 95 abuts upon wind-up of the pawl 95.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet peeling device, and more particularly to a sheet peeling device for peeling a sheet from the surface of a roller such as a fixing device.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine or a facsimile apparatus is provided with a fixing device for fixing a toner image formed on the surface of a sheet. The fixing device has a heat roller having a heater therein and a pressure roller that comes into pressure contact with the heat roller. The paper is conveyed while sandwiching the paper between both rollers to fix the toner image on the paper surface. .

In such a fixing device, a peeling claw is provided in order to prevent the paper from wrapping around the heat roller. For example, Japanese Unexamined Patent Publication No. 56-51766 and Japanese Utility Model Publication No. 5
In Japanese Patent Laid-Open No. 5-65651, a peeling claw is formed of a resin sheet, and this is elastically pressed against the outer peripheral surface of the heat roller.

[0004]

When the peeling claw as described above is pressed against the heat roller of the fixing device, it is desirable to increase the rigidity of the peeling claw in order to improve the peeling performance of the paper. However, if the rigidity is increased, the pressure contact force with respect to the heat roller becomes large, and the abrasion of the peeling claw or the local wear of the contact portion of the heat roller with the peeling claw occurs, which deteriorates the peeling performance or the fixing performance. is there. Further, if the rigidity of the peeling claw is reduced and the pressure contact force against the heat roller is reduced in order to avoid wear, there is a problem that the peeling performance deteriorates and the peeling claw rolls up and paper jam occurs.

An object of the present invention is to make the peeling claw contact the heat roller with a small pressure contact force and increase the resistance against winding up.

[0006]

A sheet peeling device according to a first aspect of the invention is a device for peeling a sheet from the surface of a roller that conveys the sheet, and includes a support member and a sheet-shaped peeling claw. . The supporting member is arranged on the downstream side of the roller in the sheet conveying direction and has a supporting portion having a predetermined length in the sheet conveying direction. The sheet-like peeling claw has a base end side fixed to a downstream portion of the support portion in the sheet conveying direction, and a tip end elastically abutting on the surface of the roller. The supporting portion has a fixing portion to which the base end portion of the peeling claw is fixed, and an extension portion extending from the fixing portion to the roller side. When the sheet is peeled off, the sheet faces the peeling claw via a predetermined gap, and the peeling claw can come into contact with the sheet when the sheet is rolled up.

A sheet peeling device according to a second aspect of the invention is a device for peeling a sheet from the surface of a roller that conveys the sheet, and includes a support member and a sheet-shaped peeling claw.
The supporting member is arranged on the downstream side of the roller in the sheet conveying direction. The sheet-like peeling claw is supported so that the base end side is supported by the supporting member, the tip end elastically contacts the surface of the roller, and the center portion in the width direction is curved so as to come closer to the roller side compared to both end portions. ing.

[0008]

In the sheet peeling apparatus according to the first aspect of the invention, the tip of the peeling claw elastically contacts the surface of the roller, and the sheet conveyed by the roller is peeled from the roller surface by the peeling claw. Here, the base end side of the peeling claw is fixed to the fixing portion of the support member, and is in contact with the roller surface by elasticity determined by the length from the fixing portion to the tip of the peeling claw. In this state, the length from the fixing part to the tip of the peeling claw can be set to be relatively long, so even if the force of the tip with respect to the bending of the peeling claw, that is, the pressure contact force is small, the roller has a sufficient moment to peel the sheet. Is in contact with.

On the other hand, when the winding force of the sheet is strong, the tip of the peeling claw is pushed in the roller rotating direction. in this case,
A part of the peeling claw comes into contact with the tip of the extension portion of the support member. In this state, the peeling claw bends in a relatively short span with the tip of the extension as a fulcrum. For this reason, the resistance against entrapment is increased. Therefore, in a normal peeling posture, a large resistance force can be applied when the peeling claw is rolled up while being brought into contact with the roller with a small pressure contact force.

In the sheet peeling device according to the second aspect of the invention, the peeling claw is curved so that the center portion in the width direction is closer to the roller side than the both end portions. Therefore, the elasticity of the peeling claw in the direction of approaching the roller is greater than the elasticity of the peeling claw in the direction of moving away from the roller. In this way, since the elastic force differs depending on the bending direction, it is possible to set the pressure contact force to the roller to be small and to increase the resistance force at the time of winding in the same manner as described above.

[0011]

1 is an external perspective view of a facsimile apparatus to which an embodiment of the present invention is applied, and FIG. 2 is a schematic vertical sectional view showing the structure thereof. As shown in these drawings, the present apparatus is provided with a reading unit 1 arranged at an upper portion for reading image information of a document.
And an output unit 2 which is arranged substantially in the center of the apparatus and forms received image information on the front surface of the paper, and a paper feeding unit 3 which is arranged at the bottom of the apparatus and supplies the paper to the output unit 2. Has been done.

The reading unit 1 has a document table 5 on which a document is placed.
And a document transport section 6 for transporting the document, and a document discharge tray 7 for storing the document discharged from the document transport section 6. An image information reading sensor 8 for reading the image information of the original is arranged in the original conveying section 6. An operation panel 9 having various keys and a display unit is arranged on the upper surface of the device. Furthermore, a handset 10 is arranged on top of the device. The output unit 2 includes an imaging unit 11 including a photosensitive drum and a developing unit 14 including a developing roller 12 and a toner cartridge 13.
And an image according to the received information
Laser device 15 for forming on the photosensitive drum surface of
And a fixing and conveying device 16 for fixing the toner image formed on the surface of the paper by the imaging unit 11. A paper discharge tray 17 is provided on the downstream side of the fixing and conveying device 16. The paper feeding unit 3 is a paper feeding cassette 21 that is detachable from an opening 20 provided at the bottom of the apparatus body, and a paper feeding device that feeds paper from the paper feeding cassette 21 and supplies the paper to the output unit 2. 22 and 22.

The apparatus main body is divided into an upper case 25 and a lower case 26, and the upper case 25 has a hinge portion 27.
It can be freely opened and closed with respect to the lower case 26. In the upper case 25, the reading unit 1 and the imaging unit 11, the developing unit 14, and the laser device 15 of the output unit 2 are included.
The lower case 26 is provided with the fixing / conveying device 16 of the output section 2 and the sheet feeding section 3.

FIG. 3 is an enlarged view of the imaging unit 11 and the fixing / conveying device 16 of the output section 2. The imaging unit 11 has a unit case 30. A mounting flange portion 31 protruding upward is formed on the upper portion of the unit case 30. A long hole 31a that is long in the vertical direction is formed in the mounting flange portion 31, and the hole 31a is locked to a pin 32 provided on the body frame side. With such a configuration, the imaging unit 11 can move in the vertical direction within a predetermined range. On the other hand, the lower portion of the unit case 30 is formed with a locking portion 33 protruding downward. The locking portion 33 locks a pin 34 provided on the main body frame side to position the imaging unit 30 in the vertical direction. A photosensitive drum 35 is rotatably attached to the end of the imaging unit 11 on the developing roller side. Further, a cleaning blade 36 for removing the toner remaining on the surface of the photosensitive drum 35 is provided on the side of the photosensitive drum 35. The toner removed from the surface of the photoconductor drum 35 by the cleaning blade 36 is stored in the storage portion 37 in the unit case 30.

Below the photosensitive drum 35, a transfer roller 40 for transferring the toner image formed on the photosensitive drum 35 to a sheet is arranged. The transfer roller 40 is
It is rotatably supported by the frame on the lower case 26 side. A main charging device 41 for charging the surface of the photoconductor drum 35 is arranged above the photoconductor drum 35. As described above, the imaging unit 11, the developing unit 14, the transfer roller 40, and the main charging device 41 constitute an image forming unit that forms a toner image on the surface of the paper. In this embodiment, the photosensitive drum 35 is negatively charged, the toner has a positive charge, and the sheet is negatively charged by the transfer roller 40.

A transport guide 45 for guiding the sheet having the toner image formed on its surface toward the fixing transport device 16 is disposed downstream of the image forming unit in the sheet transport direction. The transport guide 45 is made of antistatic resin. The antistatic resin has a surface resistivity of 10 ¹¹ Ω or more and 10
Resins of ¹³ Ω or less are used. For example, TOYOLAC PAREL TP10 manufactured by Toray Industries, Inc. (surface specific resistance value: 1 × 1
0 ¹¹ Ω) and JSR ABS EM1 manufactured by JSR Corporation
An ABS antistatic resin such as 2 (surface resistivity: 2 × 10 ¹¹ Ω) is desirable. An intermediate frame 46 is arranged above the transport guide 45 and close to the imaging unit 11. The intermediate frame 46 is made of, for example, an iron plate material and serves as a conductor. And it is grounded through another frame. In this intermediate frame, notches 46a are formed at two end portions in the width direction of the conveyed sheet.

As shown in FIGS. 3 and 4, the fixing and conveying device 16 includes a heat roller 50 having a heater 50a therein,
It has a pressure roller 51 which can be pressed against the heat roller 50. A fixing upper housing 92 is arranged on the side and above the heat roller 50 so as to cover the heat roller 50. The upper fixing housing 92 extends in the axial direction of the heat roller 50 and is detachable from a lower fixing housing (not shown). The lower fixing housing is fixed to a pair of fixing frames 53 provided at both axial ends of the rollers 50 and 51. A groove 92c is formed in the center of the upper wall of the upper fixing housing 92 along the roller axis direction, and the mounting member 54 is removably inserted into the groove 92c. The mounting member 54 has a recess 54a at the center, and a cleaning member 55 for cleaning the surface of the heat roller 50 is attached to the lower end thereof.

As shown in FIGS. 4 and 5, notches 92b are formed at two axial positions on the downstream side wall 92a of the upper fixing housing 92. The side wall 92a has almost L
The character-shaped support member 93 is fixed. The lower portion 96 of the support member 93 extends through the notch 92b into the upper fixing housing 92. In the lower portion 96 of the supporting member 93, the proximal end portion of the peeling claw 95 is adhered to the fixing portion 96a (area A1) in the downstream half thereof with an adhesive 94. Further, the extension portion 96b (area A2) of the upstream half is
It is arranged with a predetermined gap with the peeling claw 95.

The peeling claw 95 is formed of a heat-resistant resin sheet material such as polyimide, and the lower surface facing the paper is coated with a fluorine resin. The peeling claw 9
The upper surface of No. 5 needs to be adhered to the fixed portion 96a, and thus is not coated. Also, the peeling nail 9
The thickness of 5 is preferably 70 μm to 250 μm. As shown in FIG. 6, the tip of the peeling claw 95 is formed in a tapered shape and an arc shape, and elastically contacts the surface of the heat roller 50. Further, as shown in FIG. 5, the heat roller 50 is in contact with the tangent line m regarding the contact at an angle β, and the angle β is preferably in the range of 5 ° <β <45 °.

As shown in FIG. 3, the heat roller 50 has a bearing 6
It is rotatably supported by the fixing frame 53 by 0. On the other hand, the shaft 61 of the pressure roller 51 is supported by the fixing frame 53 via a bearing 62 and a spring 63. At the upper portion of the bearing 62, the protrusion 6 protruding upward is provided.
2a is formed. Further, the bearing 62 is the frame 5
3 is movable up and down, and is always urged toward the heat roller 50 by the spring 63. The bearing 60,
62 and the spring 63 are arranged at both ends in the axial direction of the roller.

On the other hand, a pressure contact release lever 65 is concentrically and rotatably attached to the outer periphery of each of the pair of bearings 60 supporting the heat roller 50. 1
The pair of pressure contact release levers 65 includes a support portion 65a that covers the outer periphery of the bearing 60, and a cam portion 6 formed in a part of the support portion 65a.
5b and an L-shaped lever portion 65c extending from the support portion 65a to the image forming portion side. The pressure contact release lever 65 is urged counterclockwise in FIG. 3 by a spring 66 whose one end is locked to the fixing frame 53. When the imaging unit 11 is attached to the apparatus, the tip of the lever portion 65c is located at the intermediate frame 4
The imaging unit 11 passes through the notch 46a of 6
Is in contact with the bottom surface of the unit case 30, so that the lever portion 65c is rotated clockwise against the urging force of the spring 66. In this state, the cam portion 6
5b is separated from the bearing protrusion 62a of the pressure roller 51. Therefore, the pressure roller 51 is pressed against the heat roller 51 by the spring 63.

As shown in FIGS. 7 and 8, two notches 70a and 70b are formed on the side wall 92d of the upper fixing housing 92 on the image forming portion side, and the notch 70 is formed.
A locking portion 71 is formed between a and 70b. The thermal fuse 7 is inserted so that the locking portion 71 passes inside the housing.
2 is locked, and both ends of the thermal fuse 72 are screwed to the outer surface of the housing side wall 92d. Although not shown, an electric wire connected to the internal heater 50a of the heat roller 50 is connected to the screw stopper. Entry guides 92e and 71a are formed at the lower end of the side wall 92d and the locking portion 71 so that the supplied sheet is guided between the heat roller 50 and the pressure roller 51. With such a configuration, when the thermal fuse 72 is arranged close to the heat roller 50, the gap between the two can be easily and accurately adjusted.

As shown in FIGS. 3 and 5, the intermediate frame 46 also extends above the fixing and conveying device 16 and constitutes a partition frame 47 for separating the fixing and conveying device 16 and the upper part thereof. . The partition frame 47 has both right and left side portions inclined upward so that the portion directly above the mounting member 54 is the lowest, and the inclined surfaces 47a and 47b and the collecting portion where the water droplets attached to the inclined surfaces 47a and 47b are concentrated. 47
c and.

As shown in FIG. 3, a pair of discharge rollers 75 and 76 are arranged on the downstream side of the fixing and conveying device 16. The upper roller 75 is fixed to a drive shaft 77 supported by the fixing frame 53. On the other hand, the lower roller 76 is rotatably supported by a fixing lower housing (not shown). As shown in FIGS. 9 and 10, the lower roller 76 has a plurality of arcuate grooves 76a on its outer peripheral surface. As shown in an enlarged manner in FIG. 10, the angle α formed by the groove end surface and the outer peripheral surface of the arcuate groove 76a is set to be 90 ° or less. Therefore, when the lower roller 76 rotates in the direction of arrow A in FIG. 10 to eject the sheet, the trailing edge of the sheet gradually enters the groove 76a as the sheet rotates, and the sheet is reliably ejected. Sent to the side.

The fixing and conveying device 16 is attached to the main body of the apparatus by attaching the fixing frames 53 arranged at both ends thereof to the attachment frames 80 as shown in FIG.
The fixing frame 53 has a first hook portion 81 and a second hook portion 82 at the lower end thereof, and the flange portion 8 at the side portion on the discharge side.
Have three. Further, the attachment frame 80 has a mounting portion 80e on which the fixing frame 53 is mounted and a vertical portion 80d. The first hook portion 81 of the fixing frame 53 is
It has a protruding portion 81a protruding toward the image forming portion side, and the upper end portion thereof has a curved shape. First hook portion 81
Is inserted into a notch 80a formed in the mounting frame 80. Here, as shown in FIG. 13, the attachment frame 80 is formed with a locking portion 80b that projects into the notch 80a, and the protruding portion 81a of the first hook portion 81 engages with this locking portion 80b. It can be stopped. The locking portion 80b can be elastically deformed by a predetermined amount. The relationship between the dimension t1 between the upper surface of the protruding portion 81a and the lower end surface of the fixing frame 53 and the plate thickness t0 of the mounting frame 80 is t0> t1 (for example, t0 = 1.2 mm, t1 = 1. ．
15 mm). Therefore, when the first hook portion 81 is locked to the locking portion 80b, the tip of the locking portion 80b is elastically deformed upward.

On the other hand, the second hook portion 82 has a protruding portion 82a which protrudes toward the first hook portion 81 side. Protruding part 8
The upper surface of 2a is an inclined surface 82b whose tip is inclined downward. The second hook portion 82 is provided on the mounting frame 80 side.
A notch 80c is formed corresponding to the. Notch 80
The size of c is such that the entire first hook portion 82 can be inserted. Further, the base end of the inclined surface 82b and the fixing frame 5
3 The dimension t2 between the lower end surface and the plate thickness t of the mounting frame 80
The relationship with 0 is: t0 <t2 (for example, t0 = 1.2 mm, t2 = 1.
3 mm).

The vertical portion 80d is the mounting frame 80.
Is bent upward from the end of the mounting portion 80e. A screw hole 84 is formed in the vertical portion 80d so that the flange portion 83 of the fixing frame 53 can be attached with a screw 85. Here, as shown by the alternate long and short dash line in FIG. 12, when the fixing and conveying device 16 is mounted on the mounting frame 80 and the second hook portion 82 is in contact with the end surface of the notch 80c of the mounting frame 80, A slight gap t3 (for example, 0.1 to 0.1) is formed between the vertical portion 80d.
0.5 mm) is set to open.

When the fixing / conveying device 16 having such a fixing frame 53 is mounted on the mounting frame 80 of the main body of the apparatus, first, both hook portions 81, 8 of the fixing frame 53 are mounted.
2 is inserted into the notches 80a and 80c of the mounting frame 80. In this state, when the fixing frame 53 is moved to the right in FIG. 10, the protruding portion 82a of the second hook portion 82 is formed.
Is guided downward by the contact between the inclined surface 82b and the end surface of the notch 80c. Further, the first hook portion 81 is guided so that the projecting portion 81a extends under the locking portion 80b. In this manner, the fixing / conveying device 16 can be temporarily fixed in the vertical direction simply by moving the fixing frame 53 in the horizontal direction.

In the temporarily fixed state, a gap t3 is formed between the vertical portion 80d of the mounting frame and the flange portion 83 of the fixing frame 53. In this state, screws 85
When is screwed into the screw hole 84 and tightened, the flange portion 83 bends and comes into close contact with the vertical portion 80d. The fixing conveyance device 16 is firmly fixed to the mounting frame 80 by the bending force of the flange portion 83.

By using the fixing frame 53 and the mounting frame 80 as described above, even when the fixing frame 53 cannot be fixed by screws from above in the mounting direction, the fixing frame 53 can be easily positioned and securely fixed. In the embodiment having such a configuration, the imaging unit 11 is not mounted, for example, at the time of shipping the product. In this case, as shown in FIG. 14, the lever portion 65c of the press contact release lever 65 is provided with the cutout 4 of the intermediate frame 46.
It is possible to rotate upward through 6a. Therefore, the lever portion 65c is rotated counterclockwise in FIG. 14 by the biasing force of the spring 66. In this state, the cam portion 65b of the pressure release lever 65 contacts the bearing protrusion 62a of the pressure roller 51, and pushes the bearing 62 and the pressure roller 51 downward against the urging force of the spring 63. As a result, the pressure roller 51 is separated from the heat roller 50, and the pressure contact between the two rollers 50, 51 is released.

On the other hand, when installing this facsimile apparatus, the upper case 25 is opened and the imaging unit 11 is mounted. When the upper case 25 is closed with the imaging unit 11 attached, the lever portion 65c of the press contact release lever 65 is pushed downward by the bottom surface of the case 30 of the imaging unit 11, as shown in FIG. Then, the pressure contact release lever 6 is resisted against the biasing force of the spring 66.
5 rotates clockwise in FIG. 3, and the cam portion 65b separates from the bearing protrusion 62a of the pressure roller 51. Then, the pressure roller 51 is pushed upward by the spring 63, and the rollers 50 and 51 come into pressure contact with each other.

Further, the lever portion 65 of the pressure contact release lever 65
The bottom of the imaging unit 11 is pushed upward by c. Then, the locking portion 33 of the unit case 30 hits the pin 34, and reliable positioning is performed. Further, when the imaging unit 11 is replaced, the upper case 25 is opened and the pressing by the lever portion 65c is released, so that the gap between the photosensitive drum 35 and the developing roller 12 can be increased. Therefore, the imaging unit 1
It is possible to avoid a collision between the developing roller 12 and the photoconductor drum 35 when attaching / detaching.

As described above, the heat roller 50 and the pressure roller 51 can be automatically brought into pressure contact with each other when the imaging unit 11 is mounted, and the heat roller 50 and the pressure roller 51 are installed as compared with the case where a spacer or the like is used as in the conventional apparatus. The time can be shortened, and problems due to erroneous operation can be resolved. Further, since the rotation center of the pressure contact release lever 65 is aligned with the axis center of the heat roller 50, the rotation center axis for the lever 65 is unnecessary, and the mechanism for releasing the pressure contact is simplified. Further, since the pressure contact is released by the rotating operation, if the slope of the cam portion 65b is made gentle, the pressure contact can be released with a small force.

If the paper is jammed at the fixing / conveying device 16, the upper case 25 is opened as shown in FIG. In this case, the imaging unit 11
Since the bottom surface of the unit case 30 is separated from the tip of the lever portion 65c of the pressure contact release lever 65, the pressure contact release lever 6 is released as in the case where the imaging unit 11 is not attached.
5 rotates counterclockwise in FIG. 15, and the cam portion 65b
The pressing roller 51 is separated from the heat roller 50 by pressing. In this state, the paper jammed by the fixing and conveying device 16 can be easily taken out.

Next, the image forming operation on the sheet and the conveying operation will be described. When the facsimile device receives the information, the laser device 15 forms an electrostatic latent image on the surface of the photosensitive drum 35 according to the received content. This electrostatic latent image is visualized as a toner image by the developing unit 14. The toner image is transferred onto the surface of the paper by the transfer roller 40.

This sheet is guided to the fixing and conveying device 16 side by the conveying guide 45. At this time, the positively charged residual toner is stored in the storage portion 37 of the imaging unit 11. On the other hand, the sheet that has passed the transfer roller 40 is charged with the opposite polarity to the toner. Here, if the transport guide 45 is formed of a good conductor, the electric charge of the paper suddenly escapes via the transport guide 45, and the carrying force of the unfixed toner on the paper is lost. Therefore, the image on the surface of the paper is disturbed during the transportation. However, in this embodiment, the transport guide 4
Since 5 is formed of the antistatic resin having the surface resistivity as described above, the charge of the paper is conveyed by the conveyance guide 45.
Is gradually removed via. Therefore, the disturbance of the unfixed toner image can be suppressed.

The residual toner contained in the containing portion 37 of the unit case 30 is positively charged. Moreover, since the intermediate frame 46 is grounded, the intermediate frame 46 is negatively charged by electrostatic induction. Further, as described above, since the negative charge of the paper on the transport guide 45 gradually escapes, the electric attraction force of the paper to the residual toner in the accommodating portion 37 becomes small, and the paper is prevented from rolling up. It can be prevented. Therefore, stable transportation can be performed.

The sheet conveyed in this way is conveyed by the conveyance guide 59e and the locking portion 71 of the upper fixing housing 92.
Of the heat roller 50 and the pressure roller 51. Then, the toner image on the surface of the paper is fixed by being heated while being sandwiched between these rollers 50 and 51 by a predetermined pressure. In such a fixing operation, the paper usually contains a large amount of water, and the heat roller is temperature-controlled at 150 ° C. or higher, so that water vapor is generated from the paper immediately after passing through the heat roller 50. When this steam contacts the partition frame 47 when the inside of the machine is not sufficiently warmed, dew condensation occurs on the surface of the partition frame 47. Water droplets generated by dew condensation are concentrated on the collecting portion 47c above the mounting member 54 along the inclined surfaces 47a and 47b of the partition frame 47. Then, the water droplets that have fallen from the collecting portion 47c are not included in the recess 54a of the mounting member 54.
Accumulate inside.

The concave portion 54a of the mounting member 54 is the heat roller 50.
Is close to. Therefore, when the printing operation is continued, the water in the recess 54a is evaporated by the heat of the heat roller 50. At this time, since the inside of the machine is sufficiently warm, even if steam comes into contact with the partition frame 47 again, dew condensation does not occur. In this case, if the concave portion 54a of the mounting member 54 has a capacity capable of accommodating the maximum amount of dew condensation, it is possible to prevent water droplets from falling onto other portions such as the surface of the paper, and suppress the disturbance of the image due to water droplets. be able to. Further, since the partition frame 47 and the mounting member 54 are used, a special member such as a hygroscopic material is unnecessary.

The sheet for which the fixing operation has been completed is peeled from the heat roller 50 by the peeling claw 95. Since the tip portion of the peeling claw 95 is tapered, the tip contact portion always comes into contact with the sheet first even when the mounting posture is deviated. Therefore, it is difficult for the paper to enter between the surface of the heat roller 50 and the peeling claw 95, and the paper can be smoothly peeled from the heat roller 50.

Here, the pressure contact force of the peeling claw 95 against the heat roller 50 is determined according to the length from the fulcrum P1 to the tip by the end of the fixed portion 96a, and can be determined to be relatively small. Therefore, wear of the heat roller 50 can be reduced, and the life of the heat roller 50 can be extended. On the other hand, when peeling a strong paper or when a paper jam occurs, the peeling claw 95 is pushed upward, and the middle portion of the peeling claw 95 abuts the fulcrum P2 which is the end of the extension portion 96b. In this case, the elastic force of the peeling claw 95 is determined according to the relatively short length from the fulcrum P2 to the tip, and a relatively large force is required to deform the peeling claw 95 upward. That is, the peeling claw 95 and the supporting member 93 can increase the resistance force against the winding of the peeling claw 95 without increasing the pressure contact force of the peeling claw 95 against the heat roller 50.

Further, since the lower surface of the peeling claw 95 is coated with fluorine, contamination of the peeling claw 95 by toner or paper powder is reduced, and stable peeling performance can be obtained for a long period of time. Further, the peeling claw 95 has an angle β (5 ° <
Since it is in contact with the heat roller 50 at β <45 °), even if the thickness of the paper is thick, the paper can be smoothly moved to the heat roller 50.
Can be peeled off.

The sheet peeled from the heat roller 50 by the peeling claw 95 is discharged onto the sheet discharge tray by the discharge rollers 75 and 76. At this time, the trailing edge of the sheet enters the arc groove 76a of the lower roller 76, as shown in FIG.
In this case, since the groove end surface of the circular arc groove 76a has an acute angle with respect to the outer peripheral surface, the rear end of the sheet further enters the inside of the groove 76a as the lower roller 76 rotates. Therefore, the paper is reliably delivered to the paper discharge tray 17. Further, since the outer peripheral surface of the lower roller 76 is a curved surface having a circular arc, it is possible to prevent the paper from being damaged.

[Other Embodiments] (a) In the above embodiment, the lever portion 65c of the press contact release lever 65 is directly contacted with the bottom surface of the case of the imaging unit 11, but it may be contacted with another member. . In the embodiment shown in FIGS. 16 and 17, the intermediate frame 46
A shutter member 90 is movably arranged below the. The shutter member 90 is supported by guides 91 a and 91 b provided on the lower surface of the intermediate frame 46, and is movable in the roller axis direction of the heat roller 50. The shutter member 90 has a cutout 46 in the intermediate frame 46.
A pair of notches 9 of approximately the same size are provided at positions corresponding to a.
0a is formed. Therefore, at the position shown in FIG. 17, the cutout 46a of the intermediate frame 46 and the cutout 90a of the shutter member 90 are aligned, and the lever portion 65c can pass through these cutouts 46a, 90a. is there. On the other hand, a projecting portion 90b that projects upward is formed at one end of the shutter member 90. When the imaging unit 11 is attached to the apparatus main body, the end of the imaging unit 11 contacts the protrusion 90b of the shutter member 90, and the shutter member 90 is moved in the arrow direction of FIG. As a result, the intermediate frame 46
The notch 46a and the notch 90a of the shutter member 90 are deviated from each other, and the lever portion 65c abuts the shutter member 90 and cannot rotate upward.

In this state, as shown in FIG. 16, the cam portion 65b of the pressure contact release lever 65 is separated from the bearing protrusion 62a of the pressure roller 51, and the pressure contact between the rollers 50 and 51 is allowed. When the rigidity of the imaging unit 11 is low, when the lever portion 65c of the pressure contact release lever 65 is directly brought into contact with the imaging unit 11 as in the above embodiment, the imaging unit 11 may be bent by the spring force of the spring 66. Imaging unit 1
When 1 is bent, it adversely affects image formation.

However, in the embodiment shown in FIGS. 16 and 17, the lever portion 65c contacts the shutter member 90 and does not directly contact the imaging unit 11. Therefore, even when the rigidity of the imaging unit 11 is low, the pressure contact between the heat roller 50 and the pressure roller 51 can be automatically released without adversely affecting the image formation. (B) Another embodiment of the peeling claw is shown in FIGS.

In this embodiment, the lower part 1 of the support member 100
00a is formed in an inverted V shape as shown in FIG. 19, and the center is higher by H than both ends. The peeling claw 101 is provided on the lower portion 100 of the support member 100.
Similarly, it has an inverted V shape along a. Also,
As shown in FIG. 20, the peeling claw 101 has a tapered tip, and the tip is formed in an arc shape. The peeling claw 101 has a contact angle β with the heat roller 50,
As in the above-mentioned embodiment, they are attached so as to be in the range of 5 ° <β <45 °.

In such an embodiment, the peeling claw 101 is
Since the central portion is formed to be curved so as to be higher, the elastic force of the peeling claw 101 pushed toward the heat roller 50 side becomes larger than the elastic force of the peeling claw 101 in the direction away from the heat roller 50. It is possible to increase the resistance force against the winding of the peeling claw 101 without increasing the pressure contact force of the heat roller 50.

The shape of the peeling claw 101 is not limited to the example shown in FIG. 19, and may be curved in an arc shape, for example. (C) In the above-described embodiment, the pressure contact release lever is rotated by pressing the imaging unit 11 or the like, but as shown in FIG. 21, it may be rotated by using a drive mechanism such as a motor. .

In the example shown in FIG. 21, the pressure contact releasing member 105.
Are rotatably arranged on the outer periphery of a bearing 60 that supports the heat roller 50. A cam portion 105a for pressing the protruding portion 62a of the bearing 62 of the pressure roller 51 is formed on a part of the outer periphery thereof. A gear portion 105b is formed on a part of the outer circumference. On the other hand, a motor 107 is fixed to the fixing frame 106, and a worm gear 109 is connected to the shaft tip of the motor 107 via a joint 108. The worm gear 109 is
It meshes with the gear portion 105b of the pressure contact releasing member 105.

In such an embodiment, the pressure release member 105 can be rotated around the heat roller 50 by rotating the motor 107 and rotating the worm gear 109. Therefore, the pressure contact releasing member 105 is rotated so that the cam portion 105 a of the pressure contact releasing member 105 rotates the bearing protrusion portion 6 of the pressure roller 51.
2a, the heat roller 50 to the pressure roller 51
Can be separated.

Further, since a lever or the like is unnecessary, the heat roller 50 and the pressure roller 51 can be easily pressed and released in a very narrow space. (D) As shown in FIG. 22, the recess 54 of the mounting member 54
You may form the hole 54b in the bottom part of a. In such an embodiment, the water drops that have fallen into the recess 54a pass through the hole 54b and permeate into the cleaning member 55. Since the cleaning member 55 is in contact with the surface of the heat roller 50, the cleaning member 55 has a high heat and the water evaporates in a short time. (E) In each of the above-described embodiments, the present invention is applied to the roller portion of the fixing / conveying device 16, but it can be similarly applied to other conveying devices.

[0053]

As described above, according to the present invention, the elastic force in the direction closer to the carrying surface, that is, the elastic force in the winding direction, is larger than the elastic force in the direction in which the sheet-like peeling claw is away from the carrying surface such as the roller. For this reason, it is possible to increase the resistance force against entanglement while reducing the pressure contact force of the peeling claw against the transport surface. Therefore, it is possible to reduce the abrasion of the conveying surface while maintaining a good peeling performance of the sheet. Furthermore, it is possible to reduce the involvement of the peeling claw.

[Brief description of drawings]

FIG. 1 is an external perspective view of a facsimile device to which an embodiment of the present invention is applied.

FIG. 2 is a schematic configuration diagram of a vertical cross section of FIG.

FIG. 3 is a front view of an image forming unit and a fixing / conveying device of the apparatus.

FIG. 4 is a vertical cross-sectional configuration diagram of a fixing / conveying device.

FIG. 5 is an enlarged view of a peeling claw and a supporting portion.

FIG. 6 is a bottom view of the peeling claw.

FIG. 7 is a vertical cross-sectional configuration diagram of a fixing / conveying device.

FIG. 8 is a perspective view of a thermal fuse mounting portion of the fixing and conveying device.

FIG. 9 is a perspective view of a lower roller of the fixing / conveying device.

FIG. 10 is an enlarged partial view of a lower roller.

FIG. 11 is a partial front view of the frame of the fixing / conveying device.

FIG. 12 is a cross-sectional view of a mounting frame of the fixing / conveying device.

FIG. 13 is a perspective partial view of a frame and a mounting frame of the fixing and conveying device.

FIG. 14 is a front view of the fixing and conveying device at the time of product shipment.

FIG. 15 is a front view of the fixing / conveying device during a jam process.

FIG. 16 is a partial front view of a fixing and conveying device according to another embodiment.

FIG. 17 is a partial side view of FIG.

FIG. 18 is an enlarged partial view of a fixing / conveying device according to still another embodiment.

FIG. 19 is a side view of FIG.

FIG. 20 is a bottom view of FIG.

FIG. 21 is a partial front view of a fixing / conveying device according to still another embodiment.

FIG. 22 is a vertical cross-sectional configuration diagram of a fixing and conveying device according to still another embodiment.

[Explanation of symbols]

 16 Fixing and Conveying Device 50 Heat Roller 51 Pressure Roller 93 Supporting Member 95 Peeling Claw 96 Supporting Part 96a Fixing Part 96b Extension Part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Tanaka 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Engineering Co., Ltd.

Claims (2)

[Claims] 1. A sheet peeling device for peeling a sheet from the surface of a roller that conveys the sheet, the support being provided on the downstream side of the roller in the sheet conveying direction and having a supporting portion having a predetermined length in the sheet conveying direction. A member and a sheet-shaped peeling claw whose base end side is fixed to a downstream portion of the supporting part in the sheet conveying direction and whose tip elastically abuts on the surface of the roller, wherein the supporting part is a base of the peeling claw. There is a fixed portion having an end fixed, and an extension portion extending from the fixed portion to the roller side, and the extension portion is the peeling member when the peeling claw tip is in contact with the roller to peel the sheet. A sheet peeling device that faces a claw via a predetermined gap and can contact the peeling claw when the peeling claw is rolled up by a sheet. 2. A sheet peeling device for peeling a sheet from the surface of a roller that conveys the sheet, comprising: a supporting member disposed on the downstream side of the roller in the sheet conveying direction; and a base end side supported by the supporting member. A sheet-like peeling claw whose tip is elastically abutted on the surface of the roller and whose central portion in the width direction is curved so as to come closer to the roller side compared to both ends, Peeling device.