JP2009229477A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to detect the abnormality of a rotating body in which a heating member emitting light is arranged. <P>SOLUTION: It is constituted so that hole portions 95a and 95b pass through a position facing a photosensor 87 by the rotation of a heating roll 72. The hole portion 95a is arranged so as to pass through the position facing the photosensor 87, when the heating roll 72 is rotated. The hole portion 95b is arranged so as to pass through the position facing the photosensor 87 later than the hole portion 95a every half period of the rotation of the heating roll 72 for instance. When the heating roll 72 is cracked, the timing of detecting light leaked from the heating roll 72 by the photosensor 87 is shifted from the half period of the rotation of the heating roll 72. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Patent Document 1 includes a drive transmission member that transmits driving to a fixing roller having a notch-shaped recess provided on a peripheral surface at a longitudinal end, and the drive transmission member is inserted into a hollow portion of a core metal of the fixing roller. A fixing device having a small diameter portion is disclosed.

JP 2005-345697 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device and an image forming apparatus capable of detecting an abnormality of a rotating body in which a heating member with light emission is arranged.

  In order to achieve the above object, the present invention according to claim 1 is a fixing device that fixes a developer image held on a recording medium by passing the recording medium between two rotating members. A heating member that is disposed inside at least one of the rotating bodies and that heats the rotating body with light emission, and a light detection unit that detects light leaking from the rotating body that is disposed inside the heating member. It is a fixing device.

  The present invention according to claim 2 further includes a driving force transmission member that is provided at an axial end of the rotating body in which the heating member is disposed, and that transmits a driving force to the rotating body. The fixing device according to claim 1, wherein the detection unit detects light leaking from the rotating body on an end portion side of the rotating body where the driving force transmission member is provided.

  According to a third aspect of the present invention, the light detecting means detects light leaking from one or more holes provided on an end side of the rotating body provided with the driving force transmission member. The fixing device described.

  According to a fourth aspect of the present invention, the driving force transmitting member is a notch formed at an end of the rotating body so as to pass through the vicinity of the light detecting means after the light detecting means detects light. The fixing device according to claim 2, wherein the driving force is transmitted by contact with the fixing device.

  According to a fifth aspect of the present invention, the driving force transmitting member transmits a driving force by contacting a notch formed at an end portion of the rotating body, and the light detection means is one of the notches. The fixing device according to claim 2, wherein light leaking from the portion is detected.

  According to a sixth aspect of the present invention, in the rotating body in which the heating member is arranged, a first hole is provided at an axial end, and the driving force transmission member is the first hole. 3. The fixing device according to claim 2, wherein a second hole that overlaps the first hole is provided, and the light detection unit detects the presence or absence of light that passes through the first hole and the second hole.

  According to a seventh aspect of the present invention, in the fixing device according to any one of the first to sixth aspects, the light detecting unit further includes a light collecting member that collects light leaking from the rotating body in which the heating member is disposed. is there.

  The present invention according to claim 8 is characterized in that the light detection means further includes a light shielding member that blocks light other than light leaking from the rotating body disposed inside the heating member. It is a fixing device.

  According to a ninth aspect of the present invention, there is provided an image forming unit, a transfer unit that transfers an image formed by the image forming unit to a recording medium, and a recording medium onto which the image is transferred by the transfer unit between two rotating bodies. A fixing device for fixing the developer image held on the recording medium to the recording medium by passing the fixing device; and an abnormality detecting means for detecting an abnormality of the fixing device. The fixing device includes at least the rotating body. A heating member that is disposed inside any of the heating members that heats the rotating body with light emission; and a light detection unit that detects light leaking from the rotating body disposed inside the heating member, and the abnormality The detection unit is an image forming apparatus that detects an abnormality of the rotating body in which the heating member is disposed based on a detection result of the light detection unit.

  According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, the abnormality detecting unit detects a breakage or a rotation abnormality of the rotating body in which the heating member is disposed.

  According to the first aspect of the present invention, it is possible to detect abnormality of a rotating body in which a heating member accompanied by light emission is disposed.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, it is possible to detect an abnormality of the rotating body at a position where the rotating body is easily damaged.

  According to the third aspect of the present invention, in addition to the effect of the second aspect of the present invention, it is possible to easily detect the abnormality of the rotating body as compared with the case where the present configuration is not provided. .

  According to the fourth aspect of the present invention, in addition to the effect of the present invention according to the second or third aspect, the abnormality of the rotating body can be detected early compared to the case where the present configuration is not provided. Can do.

  According to the fifth aspect of the present invention, in addition to the effect of the second aspect of the present invention, it is possible to detect the abnormality of the rotating body without providing a hole other than the notch.

  According to the present invention of claim 6, in addition to the effect of the present invention of claim 2, it is possible to easily detect the abnormality of the rotating body as compared with the case where the present configuration is not provided. .

  According to the seventh aspect of the present invention, in addition to the effect of the present invention according to any one of the first to sixth aspects, the detection accuracy of the abnormality of the rotating body is improved compared to the case where the present configuration is not provided. Can be made.

  According to the present invention of claim 8, in addition to the effects of the present invention of any of claims 1 to 7, the detection accuracy of the abnormality of the rotating body is improved as compared with the case where the present configuration is not provided. Can be made.

  According to the ninth aspect of the present invention, it is possible to detect the abnormality of the rotating body in which the heating member with light emission is disposed.

  According to the tenth aspect of the present invention, in addition to the effect of the present invention according to the ninth aspect, it is possible to detect breakage or rotation abnormality of the rotating body.

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.

  Each paper feed unit 18 includes a paper feed unit main body 20 and a paper feed cassette 22 in which a recording medium such as 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.

  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.

  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.

  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. .

  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. .

  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 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 and detached via the opening portion 54 formed when the inclined portion 52 is opened as described above.

  The image forming apparatus main body 12 is provided with a control unit 65 that includes a CPU and a memory (not shown) and controls each part of the image forming apparatus 10.

  2 to 7, the configuration of the fixing device 36 is shown. The fixing device 36 is unitized and has a unit main body 66, and the unit main body 66 is configured by combining a first casing 68 and a second casing 70. That is, the first casing 68 and the second casing 70 are connected via a fulcrum (not shown), and the heating roll 72 is rotatably supported by the first casing 68, A pressure roll 74 is rotatably supported on the housing 70. The pressure roll 74 is pressed against the heating roll 72 by two elastic bodies 76 formed of a coil spring or the like, and a nip portion 78 is formed. Each elastic body 76 has one end fixed to a bracket (not shown) provided on the second housing 70 side, and the other end hooked on a groove provided in the first housing 68. ing.

  A heater 80 made of a lamp is disposed in the heating roll 72. The heater 80 heats the heating roll 72 with light emission. The above-described conveyance path 32 is configured in the vertical direction across the nip portion 78, and the sheet is conveyed from the bottom to the top. An inlet side chute 82 is disposed on the upstream side of the nip portion 78, and outlet side chutes 84 a and 84 b are disposed on the downstream side of the nip portion 78. The outlet side chutes 84a and 84b are provided in the first casing 68 and the second casing 70, and the outlet side chutes 84a of the second casing 70 move upward to allow the paper to pass therethrough. It is like that.

  A thermostat 86 is provided in the first casing 68 in the vicinity of the heating roll 72, and the thermostat 86 prevents a failure due to overheating of the heating roll 72. The first casing 68 is provided with a photo sensor 87 that detects light leaking from the heating roll 72 and outputs the detection result to the control unit 65 below the heating roll 72. Further, a plurality of peeling claws 88 are provided in the first casing 68 in the vicinity of the downstream side of the nip portion 78 in the axial direction of the heating roll 72 (paper width direction). The peeling claw 88 is urged toward the heating roll 72 with a weak force that does not damage the surface of the heating roll 72, the tip of the peeling claw 88 is pressed against the surface of the heating roll 72, and is wound around the heating roll 72. The paper to be removed is peeled off.

Next, the heating roll 72 and its peripheral configuration will be described in detail.
Bearings 90 and 90 are attached to the heating roll 72 at both ends slightly forward, and the first roll 68 is rotatably supported by the bearings 90 and 90. The heating roll 72 has a cylindrical core 92 and a release layer coated on the surface side of the core 92. The core 92 has an outer diameter of, for example, 25 mm and a thickness of, for example, 1 mm. The material forming the core 92 is, for example, iron or aluminum. The release layer is made of, for example, perfluoroalkoxy (PFA), and has a thickness of, for example, 30 to 100 μm.

  A gear 96 described later is fitted into one end of the core 92 of the heating roll 72 by being inserted from the direction of arrow A. A notch 94 is formed at one end of the core 92 in parallel with the axial direction. A connecting portion 104 of a gear 96 described later is fitted into the notch 94, and the gear 96 is connected to the heating roll 72. The gear 96 is engaged with another gear (not shown), and the driving force from the other gear is transmitted to the heating roll 72 via the gear 96. The heating roll 72 rotates in the direction of arrow B and the pressure roll 74 rotates in the direction of arrow C by the driving force of the gear 96.

  Furthermore, for example, two holes 95a and 95b are formed at one end of the core 92 of the heating roll 72 as shown in FIG. The holes 95a and 95b pass through a position facing the photosensor 87 as the heating roll 72 rotates. Further, the hole 95a is disposed so as to pass through a position facing the photosensor 87 slightly earlier than the notch 94 when the heating roll 72 rotates. The hole 95b is disposed so as to pass through a position facing the photosensor 87 with a delay from the hole 95a every half cycle of the rotation of the heating roll 72, for example.

  As shown in FIG. 5, the gear 96 is formed on the gear body 98, the shaft hole 100 formed inside the gear body 98, into which the heating roll 72 is inserted, and formed on the outside of the gear body 98. And a tooth 102 that receives a driving force. The gear body 98 has a connecting portion 104 connected to the heating roll 72. The connecting portion 104 is formed in a protruding shape having a width of 4 mm, for example, on the radially inner side of the gear body 98. The shaft hole 100 is formed, for example, such that the inner diameter of the gear body 98 is substantially equal to the outer diameter of the core 92, and has a stopper portion at one end.

Next, a result detected by the photosensor 87 when the heating roll 72 is rotated by the driving force transmitted by the gear 96 will be described.
FIG. 8 is a timing chart showing a result of detection by the photosensor 87 of light leaking from the heating roll 72, where (A) is a timing chart when the heating roll 72 is normal, and (B) is a heating chart. 6 is a timing chart when a crack occurs in a roll 72.
As shown in FIG. 8A, when the heating roll 72 is normal, the photo sensor 87 detects light leaking from the heating roll 72 every half cycle of the rotation of the heating roll 72.
On the other hand, for example, when a crack occurs in the heating roll 72 from the notch 94 as shown in FIG. 9, when a crack occurs in the heating roll 72 as shown in FIG. The timing detected by the sensor 87 is shifted from the half cycle of the rotation of the heating roll 72.
Therefore, the control unit 65 can detect damage or abnormal rotation of the heating roll 72 by accepting the detection result of the photosensor 87.

Next, a first modification of the fixing device 36 will be described.
FIG. 10 is a schematic diagram showing the heating roll 72 and its periphery in a first modification of the fixing device 36. In the first modification of the fixing device 36 shown in FIG. 10, the same reference numerals are given to the substantially same parts as those constituting the fixing device 36 shown in FIG.
In the first modification of the fixing device 36, the heating roll 72 is not provided with the holes 95 a and 95 b, and instead, the notch 94 is located in the axial direction of the heating roll 72 rather than the connecting portion 104 of the heating roll 72. It is formed to be long. The photo sensor 87 is disposed so as to detect light leaking from a notch 94 formed longer than the connecting portion 104.

FIG. 11 is a timing chart showing a result of detection by the photosensor 87 of light leaking from the heating roll 72 of the first modified example of the fixing device 36. FIG. 11A shows a case where the heating roll 72 is normal. It is a timing chart, (B) is a timing chart when a crack generate | occur | produces in the heating roll 72. FIG.
As shown in FIG. 11A, when the heating roll 72 is normal, the photo sensor 87 detects light leaking from the heating roll 72 for each rotation period of the heating roll 72.
On the other hand, as shown in FIG. 11B, when the heating roll 72 is cracked, the timing at which the photosensor 87 detects light leaking from the heating roll 72 is shifted from the rotation period of the heating roll 72. End up. In addition, the period (pulse width) in which the photosensor 87 detects light is longer than when the heating roll 72 is normal.
Therefore, the control unit 65 can detect damage or abnormal rotation of the heating roll 72 by accepting the detection result of the photosensor 87.

Next, a second modification of the fixing device 36 will be described.
12 and 13, a second modification of the fixing device 36 is schematically shown. In the second modified example of the fixing device 36 shown in FIGS. 12 and 13, the same reference numerals are given to substantially the same parts as those constituting the fixing device 36 shown in FIG. It is.
In the second modification of the fixing device 36, the heating roll 72 is provided with one small diameter hole portion 108. The gear 96 has a configuration in which a small diameter hole 112 is provided in a gear main body 110 having portions having different diameters. In the second modification of the fixing device 36, the small-diameter hole portion 108 of the heating roll 72 and the small-diameter hole portion 112 of the gear main body 110 are arranged so as to overlap when the gear main body 110 is fitted to the heating roll 72. ing. For example, when the heating roll 72 is cracked, the small diameter hole portion 108 and the small diameter hole portion 112 are displaced from each other.
Therefore, the control unit 65 that receives the detection result of the photosensor 87 can detect whether or not the heating roll 72 is cracked depending on the detection period of light leaking from the heating roll 72 or the presence or absence of light.

Next, a third modification of the fixing device 36 will be described.
14 and 15, a third modification of the fixing device 36 is schematically shown. In the third modification of the fixing device 36 shown in FIGS. 14 and 15, the same reference numerals are given to substantially the same parts as those constituting the fixing device 36 shown in FIG. It is.
In the third modification of the fixing device 36, the heating roll 72 is not provided with holes 95a and 95b. On the other hand, in the first casing 68, light other than light leaking from the heating roll 72 leaks from the heating roll 72 and a light shielding plate 114 that blocks light from the outside so as not to enter the paper passing area of the heating roll 72. A condensing member 116 such as a lens that collects light toward the photosensor 87 is provided.
Therefore, the control unit 65 that receives the detection result of the photo sensor 87 can detect whether or not the heating roll 72 is cracked depending on the presence or absence of light leaking from the heating roll 72.

1 is a side view illustrating an outline of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the fixing device as viewed from the side. It is a perspective view which shows the state by which the heating roll was arrange | positioned with the pressurization roll. It is a perspective view which shows the heating roll from which the gearwheel was removed, and a pressure roll. It is a perspective view which shows the detail of the gearwheel shown in FIG. FIG. 2 is a schematic diagram illustrating a heating roll of the fixing device and its periphery. It is an enlarged view which shows the edge part by the side of a notch of a heating roll. It is a timing chart which shows the result which the photo sensor detected the light which leaked from the heating roll, Comprising: (A) is a timing chart in case a heating roll is normal, (B) is the case where a crack generate | occur | produces in a heating roll It is a timing chart. It is a schematic diagram which shows the example of a failure | damage of a heating roll. FIG. 10 is a schematic diagram illustrating a heating roll and its periphery in a first modification of the fixing device. FIG. 7 is a timing chart showing a result of detection by a photosensor of light leaking from a heating roll of a first modification of the fixing device, where (A) is a timing chart when the heating roll is normal, and (B). These are timing charts when cracking occurs in the heating roll. It is a schematic diagram which shows the heating roll and its periphery in the 2nd modification of a fixing device. It is a schematic diagram which shows the gearwheel in the 2nd modification of a fixing device. It is a schematic diagram which shows the heating roll and its periphery in the 3rd modification of a fixing device. FIG. 10 is a cross-sectional view showing a heating roll and its periphery in a third modification of the fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 14 Image forming means 36 Fixing apparatus 42 Transfer apparatus 65 Control part 68 1st housing | casing 70 2nd housing | casing 72 Heating roll 74 Pressurizing roll 80 Heater 87 Photo sensor 90 Bearing 92 Core 94 Notch 95a, 95b Hole 96 Gear 104 Connecting portion 108 Small diameter hole 110 Gear body 112 Small diameter hole 114 Light shielding plate 116 Light collecting member

Claims (10)

In a fixing device for fixing a developer image held on a recording medium to the recording medium by passing the recording medium between two rotating bodies,
A heating member disposed inside at least one of the rotating bodies and heating the rotating body with light emission;
And a light detection means for detecting light leaking from the rotating body disposed inside the heating member. The heating member is provided at an axial end of the rotating body disposed inside, and further includes a driving force transmitting member that transmits a driving force to the rotating body,
The light detection means includes
The fixing device according to claim 1, wherein light leaking from the rotating body is detected on an end portion side of the rotating body where the driving force transmission member is provided. The light detection means includes
The fixing device according to claim 2, wherein light leaking from one or more holes provided on an end side of the rotating body where the driving force transmission member is provided is detected. The driving force transmission member is
The driving force is transmitted by contacting a notch formed at an end of the rotating body so as to pass through the vicinity of the light detecting means after the light detecting means detects light. Fixing device. The driving force transmission member is
A driving force is transmitted by contacting a notch formed at an end of the rotating body;
The light detection means includes
The fixing device according to claim 2, wherein light leaking from a part of the notch is detected. The rotating body having the heating member disposed therein is
A first hole is provided at the axial end;
The driving force transmission member is
Provided with a second hole overlapping the first hole;
The light detection means includes
The fixing device according to claim 2, wherein presence or absence of light passing through the first hole and the second hole is detected. The light detection means includes
The fixing device according to claim 1, further comprising a light collecting member that collects light leaking from the rotating body arranged inside the heating member. The light detection means includes
The fixing device according to claim 1, further comprising a light shielding member that blocks light other than light leaking from the rotating body disposed inside the heating member. An image forming unit;
Transfer means for transferring an image formed by the image forming unit to a recording medium;
A fixing device that fixes the developer image held on the recording medium to the recording medium by passing the recording medium onto which the image is transferred by the transfer unit between the two rotating bodies;
An abnormality detecting means for detecting an abnormality of the fixing device;
The fixing device includes:
A heating member disposed inside at least one of the rotating bodies and heating the rotating body with light emission;
And a light detecting means for detecting light leaking from the rotating body disposed inside the heating member,
The abnormality detection means includes
An image forming apparatus that detects an abnormality of the rotating body in which the heating member is disposed based on a detection result of the light detection unit. The abnormality detection means includes
The image forming apparatus according to claim 9, wherein a breakage or a rotation abnormality of the rotating body in which the heating member is disposed is detected.

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