JPH0596859U - Recording paper separation claw of fixing device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to prevent toner from accumulating on the tip of the recording paper separating claw to prevent separation failure and jamming due to the accumulated toner, and to prevent the peripheral surface of the heat roller from being damaged. The recording paper separating claw of the fixing device that is not damaged or worn. A separating claw 24 and a positioning claw 23 whose tip is positioned slightly above the tip of the separating claw 24 are provided on the sheet discharge side of the heat roller 11 of a fixing device in which a heat roller 11 and a press roller 12 are arranged in pressure contact with each other. The recording paper separating claw 20 integrally formed with is supported by the support shaft 13 by being urged by the coil spring 14, and the recording paper separating claw 20 has the positioning claw 23 in the margin portion 11B at the side end of the heat roller 11. The abutment is prevented and the swing is restricted, and the separation claw 24 is located at a predetermined distance from the peripheral surface of the heat roller 11 corresponding to the fixing action area 11A.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a fixing device for fixing toner on a recording paper surface, which is used in electrophotography, in which a roller member is arranged in pressure contact, and an acute-angled tip portion is brought into contact with the peripheral surface of the roller member on the recording paper discharge side. The present invention relates to a recording paper separating claw of a fixing device provided as a device.

[0002]

[Prior Art]

 Recently, as an image forming apparatus such as a copying machine or a printer for recording an image on a recording sheet, a photoreceptor on the surface of a photosensitive drum is exposed to form a latent image, and toner is attached to the latent image to develop (toner There is a method utilizing a so-called electrophotographic method in which the toner image is transferred to a recording sheet and fixed by a fixing device. In an image forming apparatus using such an electrophotographic method, as a fixing device, a pressure roller is arranged in pressure contact with a heated roller member (heat roller), and unfixed recording paper is sandwiched between the pair of rollers to apply heat. In many cases, a so-called heat roll fixing device is used that heats and fuses the unfixed toner by applying pressure and heat to heat the unfixed toner from a heat roller.

In the heat roll fixing device, in order to promote the peeling of the recording paper from the heat roller and prevent the recording paper from adhering to the heat roller due to the adhesive force of the melted toner or the like and causing a conveyance failure (so-called jam). In addition, the recording paper separating claw is placed in contact with the peripheral surface of the heat roller on the recording paper discharge side. The recording paper separating claw has an acute tip, is swingably supported by a shaft member, and is oscillated and urged by an urging means to form a sharp edge on the peripheral surface of the heat roller on the recording paper discharge side. It is provided in abutment.

[0004]

[Problems to be solved by the device]

 However, in the above-described conventional recording paper separating claw configuration, the toner attached to the peripheral surface of the heat roller is scraped off by the recording paper separating claw and the rear side of the recording paper separating claw (contact surface to the heat roller). On the back side), and the accumulated toner mass causes the tip claw angle to substantially increase, making it impossible to separate the recording paper satisfactorily and causing the recording paper to stick to the accumulated toner mass. There is a problem in that the convex toner image portion fixed on the recording paper is caught and a problem such as paper jam occurs. The toner adhering to the peripheral surface of the heat roller is heated by the heat roller and is in a molten state, and this fuses with the silicone oil applied to the surface of the heat roller to enhance the peeling property, and becomes highly adhesive and solidified. It becomes difficult and the recording paper becomes extremely easy to adhere.

In addition, since the tip acute angle portion is constantly urged against the peripheral surface of the heat roller by the urging force of the urging means, there is a problem that the peripheral surface of the heat roller is damaged or worn. .. A film of fluorine resin, etc. is often formed on the peripheral surface of the heat roller in order to prevent the adhesion of toner.However, scratches and abrasion of this film improve the fixing action and peeling of recording paper. I can't do it.

[0006]

[The purpose of the device]

 In view of the above circumstances, the present invention can prevent toner from accumulating on the tip of the recording paper separating claw to prevent separation failure and jamming due to the accumulated toner. An object of the present invention is to provide a recording paper separating claw of a fixing device that does not scratch or wear the surface.

[0007]

[Means for solving the problem]

 In order to achieve the above object, a recording paper separating claw of a fixing device according to the present invention is a fixing device used in an electrophotographic method in which a roller member is arranged in pressure contact, and the roller is provided on the recording paper discharge side of the roller member. A recording paper separating claw provided for peeling a recording paper from a member, wherein a positioning part that comes into contact with the roller member and a separating claw part that has a predetermined positional relationship with the positioning part are integrally formed. Is in contact with the roller member, and the separation claw portion has a predetermined distance from the outer peripheral surface of the roller member. As a result, since the separation claw portion has a predetermined distance from the outer peripheral surface of the roller member, the separation claw portion does not scrape off the toner on the surface of the roller member, and therefore toner may accumulate on the tip of the separation claw portion. Disappear. In addition to the above configuration, the invention of claim 2 is configured such that the positioning portion contacts the non-sheet passing area of the roller member, and the separating claw portion corresponds to the sheet passing area of the roller member. As a result, the positioning portion comes into contact with the paper non-passage area of the roller member, so that the peripheral surface of the paper passage area of the roller member that performs the fixing action is not damaged or worn.

[0008]

[Example of device]

 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a conceptual configuration of a fixing device including an embodiment of a recording paper separating claw of the fixing device according to the present invention. In the illustrated fixing device, a pair of fixing rolls 10 in which a heat roller 11 and a press roller 12 are vertically arranged in parallel are arranged orthogonally to the conveying direction of the fan hold paper 20 shown by an arrow in the figure. ..

The upper heat roller 11 is a cylindrical roller, and a heating element such as a halogen lamp, which is not shown, is inserted inside the roller and is heated to a predetermined temperature by the heating element. .. Although not shown, both ends thereof are rotatably supported by a support arm that is swingably supported by the chassis of the fixing device, and a gear (not shown) is fixed to one end of the fixing arm. It is designed to be rotationally driven via. The support arm is urged by a spring so that the heat roller 11 supported by the support arm swings toward the press roller 12, so that the heat roller 11 is pressed against the press roller 12 at a predetermined pressure.

The lower press roller 12 has an elastic member layer of heat-resistant silicon rubber or the like having a predetermined hardness formed around a cored bar, and is rotatably supported by both ends of the chassis of the fixing device. Has been done. Then, in a fixing operation state in which the heat roller 11 is pressed against the press roller 12 with a predetermined pressing force, the heat roller 11 is heated and driven to rotate, and the recording paper is sandwiched between the rollers 11 and 12 to apply pressure. While heating and fixing, the paper is transported and ejected. The heat roller 11 and the press roller 12 are longer than the width of the recording sheet on which fixing can be performed by a predetermined amount, and have margin portions 11B and 11B of a predetermined width on both ends of the fixing action area 11A shown by W in the figure.

A support shaft 13 is disposed on the recording paper discharge side of the heat roller 11 in parallel with the heat roller 11 so as to be separated from the heat roller 11 by a predetermined distance and fixed to the chassis of the fixing device. Recording paper separating claws 20, 20 are supported at positions corresponding to both side ends of the roller 11, respectively. The recording paper separating claw 20 has a substrate portion 22 extending from a cylindrical bearing portion 21 having a predetermined length to one side in the tangential direction on the outer periphery thereof with a width equal to the length of the bearing portion 21. At both ends in the width direction, claw portions 23 and 24 (positioning claw 23 and separation claw 24) having a predetermined width are provided so as to project. Further, a locking projection 25 having a predetermined width is provided on the outer end portion in a state of being supported by the support shaft 13 so as to project a predetermined length on the side opposite to the base plate portion 22. Both claws 23, 24 are formed at an acute angle by an upper surface parallel to the upper surface of the base plate 24 and a lower surface having an upward slope toward the upper surface side, and the tip of the positioning claw 23 is slightly formed by the tip of the separation claw 24. It is formed so as to be located on the upper surface side (about 0 to 0.1 mm).

The recording paper separating claw 20 is provided such that a bearing portion 21 is rotatably fitted to and supported by a support shaft 13, and the claw portions 23 and 24 are brought into contact with and separated from the heat roller 11 by the rotation. ing. Further, the axial position of the positioning claw 23 corresponds to the marginal portion 11B on the outer end side of the fixing action area 11A of the heat roller 11, and the separation claw 24 corresponds to the fixing action area 11A of the heat roller 11. It is set. Further, the other end of the coil spring 14 which is externally inserted to the support shaft 13 and whose one end is fixed to the support shaft 13 is locked to the upper side of the locking protrusion 25, and the elastic return force of the coil spring 14 causes the claw portion to be engaged. 23 and 24 are oscillated and urged toward the side close to the heat roller 11.

The swing of the recording paper separating claw 20 by the coil spring 14 is restricted by the front end of the positioning claw 23 contacting the heat roller 11. That is, in this embodiment, the positioning claw 23 serves as a positioning portion. The front end of the positioning claw 23 corresponds to the margin portion 11B of the heat roller 11, and as shown in FIG. 2 which is a side view in the circumferential direction, the positioning claw 23 is provided in a predetermined direction from the pressure contact portion with the press roller 12 to the front side in the rotation direction. Abut the angular position. On the other hand, the tip of the separation claw 24 corresponds to the fixing action area 11A of the heat roller 11 and is located at the same position in the circumferential direction as the position where the positioning claw 23 abuts as shown in FIG. Correspondingly, the tip end thereof is in a state of being separated from the peripheral surface of the heat roller 11 by a height difference (X) from the tip end of the positioning claw 23 described above. In this state, the lower surface of the tip of the separation claw 24 is substantially horizontal.

According to the recording paper separating claw 20 configured as described above, the recording paper 1 which has completed the fixing action as shown in FIG. 3 is adhered to the heat roller 11 by the adhesive force of the toner or the like. Even in such a case, the separation claw 24 can be used for separation, and the conveyance path can be regulated substantially horizontally along the lower surface to discharge the sheet. Here, the tip of the separation claw 24 is not pressed against the peripheral surface of the heat roller 11, and a distance is set between the tip and the peripheral surface of the heat roller 11 so that the separation claw 24 adheres to the heat roller 11. Scraped toner is scraped off and prevented from accumulating on the back side. Further, the peripheral surface of the heat roller 11 is not damaged by the separation claw 24.

On the other hand, the tip of the positioning claw 23 is pressed against the peripheral surface of the heat roller 11 by the elastic restoring force of the coil spring, but the contact portion is the fixing action area of the heat roller 11 as described above. Since it is the margin portion 11B on the outer end side of 11A, even if the circumferential surface of the heat roller 11 is damaged by the positioning claw 23, there is no problem in the fixing action due to that, and the positioning is performed. The claw 23 does not hinder the conveyance of the recording paper.

In the above embodiment, the positioning portion is configured as the positioning claw 23 having substantially the same shape as the separation claw 24, but the present invention is not limited to this, and the shape can be appropriately changed. .. Further, the contact position with the roller member (heat roller 11) does not have to be the position corresponding to the separation claw 24. Furthermore, the positioning claw 23 may be in contact with the fixing action area 11A of the heat roller 11 only in order to prevent toner from accumulating on the separation claw that separates the recording paper from the roller member.

[0017]

[Effect of the device]

 As described above, according to the recording paper separating claw of the fixing device according to the present invention, the toner is not accumulated on the tip of the recording paper separating claw, and the recording paper separation defect or the jam caused by the accumulated toner is prevented. Occurrence can be prevented. Also, by making the positioning portion correspond to the non-sheet passing area of the roller member, the peripheral surface of the roller member that performs the fixing action is not damaged or worn, and the fixing action can be incomplete. Absent.

[Brief description of drawings]

FIG. 1 is a perspective view showing a conceptual configuration of a fixing device including an embodiment of a recording paper separating claw of the fixing device according to the present invention.

FIG. 2 is a side view thereof.

FIG. 3 is a sectional view showing a separation claw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Recording paper 11 ... Heat roller (roller member) 11A ... Fixing action area (paper passing area) 11B ... Spare part (non-paper passing area) 12 ... Press roller (roller member) 13 ... Support shaft (support member) 14 ... Coil spring (biasing means) 20 ... Recording paper separating claw 23 ... Positioning claw (positioning part) 24 ... Separation claw (separating claw part)

Claims (3)

[Scope of utility model registration request] 1. A recording paper separating device provided in a fixing device for use in an electrophotographic method, wherein a roller member is arranged in pressure contact with the recording paper, the recording paper discharging side of the roller member being provided to separate the recording paper from the roller member. A pawl, a positioning portion that comes into contact with the roller member, and a separation pawl portion that has a predetermined positional relationship with the positioning portion are integrally formed, and the positioning portion comes into contact with the roller member, The recording paper separating claw of the fixing device, wherein the portion is configured to have a predetermined distance from the outer peripheral surface of the roller member. 2. The positioning portion abuts on a non-sheet passing area of the roller member, and the separation claw portion is configured to correspond to a sheet passing area of the roller member. The recording paper separating claw of the fixing device described in. 3. The recording paper separating claw is swingably supported by a support member, and is biased by a biasing means so that the positioning portion comes into contact with the roller member. The recording paper separating claw of the fixing device according to claim 1 or 2.