JP2006126876A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make transported recording paper not enter into between the front end of a separation member and a roller. <P>SOLUTION: A fixing device has a roller for fixation, a separation member which is swung to make the front end 82 contact and leave the roller, and a recording paper guide portion which supports the separation member in a free swinging state and is brought into contact with transported recording paper 15, and has a holder 47 arranged in a free swinging state. When the holder 47 is swung as the recording paper guide portion is pushed, the front end 82 of the separation member is made to leave the roller and the front end 82 is made to leave the roller, the front end 82 is swung toward the roller as the front end 82 is pushed by the transported recording paper 15. If paper is jammed, the holder 47 is rotated against the energizing force of a spring, but the separation member is pushed by the recording paper 15 to be rotated in the opposite direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fixing device.

  Conventionally, in an electrophotographic recording apparatus, the surface of a photosensitive drum is uniformly and uniformly charged by a charging device, and is exposed by an exposure device to form an electrostatic latent image. The electrostatic latent image is developed by a developing device to become a toner image, and the toner image is transferred to a recording sheet by a transfer device and fixed by a fixing device.

  FIG. 2 is a cross-sectional view of a conventional fixing device, and FIG. 3 is a plan view of a main part of a conventional separation claw unit.

  In the figure, reference numeral 11 denotes a fixing unit, and the fixing unit 11 is rotatably disposed on a heat roller 12 and below the heat roller 12, and is urged by a biasing means such as a spring (not shown). A backup roller 13 pressed against the heat roller 12, a fixing unit casing 14 that houses the heat roller 12 and the backup roller 13, and a swingable arrangement with respect to the fixing unit casing 14. Is provided with a separation claw unit 80 for separating the recording paper 15 when it is wound around and attached. A halogen lamp 12a as a heating source is disposed in the heat roller 12.

  The separation claw unit 80 includes a separation claw 16 having a substantially triangular shape, a guide roller 17 that guides the recording paper 15 separated by the separation claw 16 backward (to the right in FIG. 2), and a predetermined A spring 18 is provided to press the tip 82 of the separation claw 16 against the heat roller 12 by an urging force. The separation claw 16 is supported by a shaft 81 so as to be swingable, and the guide roller 17 is supported by a shaft 83 so as to be rotatable with respect to the separation claw 16.

  A discharge mechanism unit 22 is disposed behind the fixing unit 11. The discharge mechanism unit 22 is rotatably disposed above the transport roller 19, and is rotatably disposed above the transport roller 19. In addition, a pinch roller 20 that is pressed against the transport roller 19 and a leaf spring 21 that presses the pinch roller 20 against the transport roller 19 by a predetermined biasing force are provided.

  Next, the operation of the fixing device having the above configuration will be described.

  First, a toner image on a photosensitive drum (not shown) is transferred to the recording paper 15 by a transfer device (not shown), and the recording paper 15 after the toner image is transferred is in the direction of arrow A as the photosensitive drum rotates. To the fixing unit 11. Then, the recording paper 15 that has reached the fixing unit 11 is sandwiched between the heat roller 12 and the backup roller 13 that are rotated in the direction of the arrow, is pressed, and is heated by the heat roller 12. As a result, the toner image is fixed on the recording paper 15 and printing is completed.

  The recording paper 15 on which the toner image has been fixed is further conveyed along with the rotation of the heat roller 12 and the backup roller 13, sent to the discharge mechanism 22, and discharged along with the rotation of the conveyance roller 19 and the pinch roller 20. Is done.

  Next, the operation of the separation claw unit 80 will be described.

  In this case, in the printing standby state, the separation claw 16 is placed at a position indicated by a broken line in FIG. 2, and the tip 82 is brought into contact with the heat roller 12. When the front end of the recording paper 15 comes into contact with the protruding portion 16a of the separation claw 16, the separation claw 16 is pushed by the recording paper 15 and rotated in the arrow B direction against the urging force of the spring 18. Move to the position indicated by the solid line in FIG. At this time, the tip 82 is separated from the heat roller 12. When the stopper 16b of the separation claw 16 abuts against the fixing unit casing 14, further rotation of the separation claw 16 is restricted, and at this time, the amount that the tip 82 is separated from the heat roller 12, that is, the separation amount is The maximum value is t.

Subsequently, the recording paper 15 is further conveyed by the conveying roller 19 and the pinch roller 20, and when the rear end of the recording paper 15 passes through the protruding portion 16a, the separation claw 16 returns to the position indicated by the broken line in FIG. (See, for example, Patent Document 1).
JP-A-8-314318

  However, in the conventional fixing device, when the recording paper 15 becomes bellows for some reason and a paper jam occurs, the separation claw 36 is rotated in the arrow B direction against the urging force of the spring 18. Then, the leading edge 82 may be separated from the heat roller 12, and the recording paper 15 may enter between the leading edge 82 and the heat roller 12.

  In this case, when the recording paper 15 is pulled to release the paper jam, the recording paper 15 is caught by the leading end 82 and is torn, and a piece of recording paper 15 remains between the leading end 82 and the heat roller 12.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device that solves the problems of the conventional fixing device and prevents the conveyed recording paper from entering between the leading end of a separating member and a roller.

  For this purpose, in the fixing device of the present invention, a fixing roller, a separation member that is swingably disposed, and whose tip is brought into contact with and separated from the roller in accordance with the swinging, and the separation member are swingable. And a holder that is provided with a recording paper guide portion that is brought into contact with the conveyed recording paper and is swingably disposed.

  When the holder is swung as the recording paper guide is pushed by the conveyed recording paper, the tip of the separation member is separated from the roller, and the tip of the separation member is When being separated from the roller, the leading end of the separation member is swung toward the roller as it is pushed by the conveyed recording paper.

  According to the present invention, in the fixing device, the fixing roller, the separation member that is swingably disposed, and whose tip is brought into contact with and separated from the roller in accordance with the swinging, and the separation member can be swung freely. And a holder that is provided with a recording paper guide portion that is brought into contact with the conveyed recording paper and is swingably disposed.

  When the holder is swung as the recording paper guide is pushed by the conveyed recording paper, the tip of the separation member is separated from the roller, and the tip of the separation member is When being separated from the roller, the leading end of the separation member is swung toward the roller as it is pushed by the conveyed recording paper.

  In this case, when the recording paper becomes bellows for some reason and paper jam occurs, the holder is pushed by the recording paper and rotated against the urging force of the spring. And is rotated in the opposite direction.

  Accordingly, since the leading end of the separating member and the roller are brought into contact with each other, the recording paper does not enter between the leading end and the roller.

  As a result, when the recording paper is pulled to release the paper jam, the recording paper is not caught by the leading edge and is not torn, so that a piece of recording paper does not remain between the leading edge and the roller.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view of the fixing device according to the first embodiment of the present invention, and FIG. 4 is a plan view of the main part of the separation claw unit according to the first embodiment of the present invention.

  In the figure, reference numeral 31 denotes a fixing unit. The fixing unit 31 is a heat roller 12 as a roller member that is rotatably arranged, and is rotatably arranged below the heat roller 12, such as a spring (not shown). When the backup roller 13 pressed against the heat roller 12 by the urging means, the fixing roller casing 14 that accommodates the heat roller 12 and the backup roller 13, and the recording paper 15 are wound around and attached to the heat roller 12, the recording paper 15 is separated. The separation claw unit 85 is provided. A halogen lamp 12a as a heating source is disposed in the heat roller 12.

  The separation claw unit 85 includes first and second guides for guiding the separation claw 36 having a substantially triangular shape and the recording paper 15 separated by the separation claw 36 backward (rightward in FIG. 1). The rollers 37a and 37b, the second guide roller 37b against the recording paper 15 by a predetermined biasing force, the spring 18 pressing the tip 82 of the separation claw 36 against the heat roller 12, and the second guide roller by a predetermined biasing force. A spring 39 for urging 37b downward is provided.

  The separation claw 36 is swingably disposed with respect to the fixing unit casing 14 by a shaft 81, and the tip 82 is brought into contact with and separated from the heat roller 12 along with the swing. The first and second guide rollers 37 a and 37 b are swung around the shaft 81 as the separation claw 36 is swung. The first guide roller 37a is rotatable with respect to the separation claw 36 by a shaft 86, and the second guide roller 37b is rotatable with respect to the separation claw 36 by a shaft 38, and a long groove 36d. The inside is supported so as to be movable relative to the separation claw 36. The spring 39 is wound around the outer periphery of the shaft 81, and one end is locked to the locking portion 36 a of the separation claw 36 and the other end is locked to the shaft 38. The first guide roller 37a is disposed upstream of the second guide roller 37b in the conveyance path for conveying the recording paper 15.

  Further, a discharge mechanism unit 22 is disposed behind the fixing unit 31. The discharge mechanism unit 22 is rotatably disposed above the transport roller 19, and is rotatably disposed above the transport roller 19. In addition, a pinch roller 20 that is pressed against the transport roller 19 and a leaf spring 21 that presses the pinch roller 20 against the transport roller 19 by a predetermined biasing force are provided.

  Next, the operation of the fixing device having the above configuration will be described.

  First, a toner image on a photosensitive drum (not shown) is transferred to the recording paper 15 by a transfer device (not shown), and the recording paper 15 after the toner image is transferred is in the direction of arrow A as the photosensitive drum rotates. To the fixing unit 31. Then, the recording paper 15 that has reached the fixing unit 31 is sandwiched between the heat roller 12 and the backup roller 13 that are rotated in the direction of the arrow, is pressed, and is heated by the heat roller 12. As a result, the toner image is fixed on the recording paper 15 and printing is completed.

  Then, the recording paper 15 on which the toner is fixed is further conveyed along with the rotation of the heat roller 12 and the backup roller 13, sent to the discharge mechanism 22, and discharged along with the rotation of the conveyance roller 19 and the pinch roller 20. The Reference numeral 15 a denotes a printing surface of the recording paper 15.

  Next, the operation of the separation claw unit 85 will be described. In addition, about the thing which has the same structure as FIG. 1, the description is abbreviate | omitted by providing the same code | symbol.

  FIG. 5 is a diagram showing a first state of the separation claw unit in the first embodiment of the present invention, FIG. 6 is a diagram showing a second state of the separation claw unit in the first embodiment of the present invention, FIG. 7 is a diagram showing a third state of the separation claw unit according to the first embodiment of the present invention.

  In the printing standby state, as shown in FIG. 5, the recording paper 15 is not in contact with the separation claw 36 and the second guide roller 37 b, and the tip 82 of the separation claw 36 is brought into contact with the heat roller 12.

  Then, as shown in FIG. 6, when the front end of the recording paper 15 comes into contact with the second guide roller 37b, the second guide roller 37b is pushed by the recording paper 15, and the separation claw 36 The tip 82 is rotated in the direction of arrow B against the urging force, and the tip 82 is separated from the heat roller 12. When the stopper portion 36b of the separation claw 36 abuts against the fixing unit casing 14, further rotation of the separation claw 36 is restricted, and at this time, the amount that the tip 82 is separated from the heat roller 12, that is, the separation amount is The maximum value is t.

  Subsequently, the recording paper 15 is conveyed backward (rightward in the drawing) by the conveying roller 19 (FIG. 1) and the pinch roller 20, and when the rear end of the recording paper 15 passes through the second guide roller 37b, the separation claw 36 is provided. Is again placed in the standby state shown in FIG.

  FIG. 7 shows a state of the separation claw unit 85 when the recording paper 88 stronger than the recording paper 15 shown in FIG. 6 is used.

  In this case, the separation claw 36 is placed at the same position as in FIG. 6, the stopper portion 36 b of the separation claw 36 abuts against the fixing unit casing 14, and the separation amount of the tip 82 becomes the maximum value t. The shaft 38 is moved upward in the long groove 36d, and the second guide roller 37b is pushed upward.

  As described above, in the present embodiment, even when the second guide roller 37b of the separation claw 36 placed in the standby state is overlapped with the conveyance path of the recording paper 15, the recording paper 15 is conveyed. As a result, the second guide roller 37b is rotated, so that the printing surface 15a and the second guide roller 37b are not rubbed. Therefore, for example, when solid black printing is performed, the gloss is equal between the portion of the printing surface 15a that contacts the separation claw 36 and the portion that does not contact, so that the image quality can be improved.

  Further, when the stiff recording paper 88 is used, the same separation amount is ensured and the second guide roller 37b is pushed upward, so that damage to the recording paper 88 can be reduced.

  Next, a state when a paper jam occurs in the fixing device will be described. In addition, about the thing which has the same structure as FIG. 1, the description is abbreviate | omitted by providing the same code | symbol.

  FIG. 8 is a diagram showing a state when a paper jam occurs in the first embodiment of the present invention.

  As shown in the figure, when the recording paper 15 becomes bellows for some reason and the paper jam occurs, the second guide roller 37b is pushed by the recording paper 15, and the separation claw 36 is biased by the spring 18. The tip 82 is moved away from the heat roller 12.

  At this time, the recording paper 15 may enter between the leading end 82 and the heat roller 12.

  In this case, when the recording paper 15 is pulled in the direction of arrow C to release the paper jam, the recording paper 15 is caught by the leading end 82 and is torn, and a piece of recording paper 15 remains between the leading end 82 and the heat roller 12. End up.

  Therefore, a second embodiment of the present invention in which the recording paper 15 does not enter between the leading end 82 and the heat roller 12 will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol.

  FIG. 9 is a cross-sectional view of the fixing device according to the second embodiment of the present invention, FIG. 10 is a plan view of the main part of the separation claw unit according to the second embodiment of the present invention, and FIG. It is a principal part rear view of the separation nail | claw unit in embodiment.

  In the figure, the separation claw unit 89 has a separation claw 46 having a substantially triangular shape, a holder 47 for swingably supporting the separation claw 46, and the recording paper 15 separated by the separation claw 46 behind (see FIG. 9). The second guide roller 48b is moved to the recording paper 15 by the first and second guide rollers 48a and 48b guided to the right) and a predetermined urging force, and the tip 82 of the separation claw 46 is used as a roller member. A spring 18 is provided to press against the heat roller 12. The holder 47 is provided with a holding portion 47a for positioning the spring 18 at a predetermined location, and the separation claw 46 is provided with a stopper portion 46b for setting the distance of the tip 82.

  The holder 47 is swingably disposed with respect to the fixing unit casing 14 by a shaft 81, and the separation claw 46 is swingably disposed with respect to the fixing unit casing 14 and the holder 47 about the shaft 81. The tip 82 is brought into and out of contact with the heat roller 12 as it swings. Accordingly, the first and second guide rollers 48 a and 48 b are swung around the shaft 81 as the separation claw 46 is swung, and the second guide roller 48 b is relatively opposed to the separation claw 46. It is arranged to be freely movable.

  The first guide roller 48a is rotatably supported by the shaft 86 with respect to the separation claw 46, and the second guide roller 48b is rotatably supported by the shaft 47 with respect to the holder 47.

  By the way, in the present embodiment, even when a paper jam occurs, a separation claw is provided at a predetermined position of the separation claw 46 so that the recording paper 15 does not enter between the leading end 82 and the heat roller 12. A pin 46 c as a holding member is fixed, and first and second stopper portions 47 b and 47 c are formed to project from the edge portion of the holder 47 in order to restrict the rotation range with respect to the holder 47. .

  Next, the operation of the separation claw unit 89 having the above configuration will be described.

  FIG. 12 is a diagram showing a first state of the separation claw unit according to the second embodiment of the present invention, FIG. 13 is a rear view of FIG. 12, and FIG. 14 is a separation claw unit according to the second embodiment of the present invention. FIG. 15 is a rear view of FIG. 14, FIG. 16 is a view showing a third state of the separation claw unit according to the second embodiment of the present invention, and FIG. 17 is a rear view of FIG. FIG.

  In the standby state, as shown in FIGS. 12 and 13, the recording paper 15 is not in contact with the separation claw 46 and the second guide roller 48 b, and the tip 82 of the separation claw 46 is brought into contact with the heat roller 12. At this time, since the pin 46c is brought into contact with the second stopper portion 47c, the separation claw 46 does not further rotate due to its own weight.

  14 and 15, when the front end of the recording paper 15 comes into contact with the second guide roller 48b, the second guide roller 48b is pushed by the recording paper 15 and the holder 47 is moved by the spring 18. It is rotated in the direction of arrow D against the urging force. At this time, the separation claw 46 is rotated by its own weight as the holder 47 rotates, and the tip 82 is separated from the heat roller 12. When the stopper portion 46b of the separation claw 46 is brought into contact with the fixing portion casing 14, further rotation of the separation claw 46 is restricted, and at this time, the separation amount of the tip 82 becomes the maximum value t.

  Subsequently, the recording paper 15 is conveyed rearward by the conveying roller 19 (FIG. 9) and the pinch roller 20, and when the rear end of the recording paper 15 passes through the second guide roller 48b, the separation claw 46 is moved to the positions shown in FIGS. It is put in the waiting state shown in FIG.

  16 and 17 show the state of the separation claw unit 89 when the recording paper 88 which is stronger than the recording paper 15 shown in FIGS. 14 and 15 is used.

  In this case, the separation claw 46 is placed at the same position as in FIGS. 14 and 15, the stopper portion 46 b of the separation claw 46 hits the fixing unit casing 14, and the separation amount of the tip 82 becomes the maximum value t. Then, the shaft 38 is moved upward in the long groove 36d (FIG. 1), and the second guide roller 48b is pushed upward. At this time, the separation amount of the tip 82 is in a state where the maximum value t is maintained and is the same as the position shown in FIGS. 14 and 15, but the holder 47 and the guide roller 48b are pushed upward.

  As described above, in the present embodiment, even when the second guide roller 48b of the separation claw 46 placed in the standby state is overlapped with the conveyance path of the recording paper 15, the recording paper 15 is conveyed. As the second guide roller 48b is rotated with this, the printing surface 15a and the second guide roller 37b are not rubbed. Therefore, for example, when solid black printing is performed, the gloss is equal between the portion in contact with the separation claw 46 on the printing surface 15a and the portion not in contact with it, so that the image quality can be improved.

  Further, when the stiff recording paper 88 is used, the same separation amount is ensured, and the second guide roller 48b is pushed upward, so that damage to the recording paper 88 can be reduced.

  By the way, when the recording paper 15 becomes bellows for some reason and the paper jam occurs, the second guide roller 48b is pushed by the recording paper 15, and the holder 47 moves against the urging force of the spring 18 by the arrow D. The separation claw 46 is pushed by the recording paper 15 and rotated in the direction opposite to the arrow D direction.

  Therefore, since the leading edge 82 and the heat roller 12 are brought into contact with each other, the recording paper 15 does not enter between the leading edge 82 and the heat roller 12.

  As a result, when the recording paper 15 is pulled to release the paper jam, the recording paper 15 is not caught by the leading edge 82 and is not torn, so that the piece of recording paper 15 is separated between the leading edge 82 and the heat roller 12. There is no time left.

  The present invention is not limited to the above embodiments, and various modifications can be made based on the gist of the present invention, and they are not excluded from the scope of the present invention.

1 is a cross-sectional view of a fixing device according to a first embodiment of the present invention. It is sectional drawing of the conventional fixing device. It is a principal part top view of the conventional separation claw unit. It is a principal part top view of the separation nail | claw unit in the 1st Embodiment of this invention. It is a figure which shows the 1st state of the separation nail | claw unit in the 1st Embodiment of this invention. It is a figure which shows the 2nd state of the separation nail | claw unit in the 1st Embodiment of this invention. It is a figure which shows the 3rd state of the separation nail | claw unit in the 1st Embodiment of this invention. FIG. 6 is a diagram illustrating a state when a paper jam occurs in the first embodiment of the present invention. It is sectional drawing of the fixing device in the 2nd Embodiment of this invention. It is a principal part top view of the separation nail | claw unit in the 2nd Embodiment of this invention. It is a principal part rear view of the separation nail | claw unit in the 2nd Embodiment of this invention. It is a figure which shows the 1st state of the separation nail | claw unit in the 2nd Embodiment of this invention. FIG. 13 is a rear view of FIG. 12. It is a figure which shows the 2nd state of the separation nail | claw unit in the 2nd Embodiment of this invention. It is a rear view of FIG. It is a figure which shows the 3rd state of the separation nail | claw unit in the 2nd Embodiment of this invention. FIG. 17 is a rear view of FIG. 16.

Explanation of symbols

12 Heat rollers 15, 88 Recording paper 36, 46 Separation claw 36b, 46b Stopper portions 37a, 37b, 48a, 48b First and second guide rollers 47 Holder 82 Tip

Claims (2)

(A) a fixing roller;
(B) a separating member that is swingably disposed and whose tip is brought into contact with and separated from the roller along with the swinging;
(C) having a recording paper guide portion that supports the separation member in a swingable manner and is brought into contact with the transported recording paper, and has a holder that is swingably disposed;
(D) When the holder is swung as the recording paper guide is pushed by the conveyed recording paper, the tip of the separation member is separated from the roller;
(E) When the leading end of the separating member is separated from the roller, the leading end of the separating member is swung toward the roller side as it is pushed by the conveyed recording paper. A fixing device characterized. The fixing device according to claim 1, wherein the separation member is provided with a stopper portion for setting a separation amount of a tip.

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