JPH08160802A - Fixing device - Google Patents

Abstract

PURPOSE: To provide a fixing device capable of satisfying conditions for reducing the number of parts and assembly man-hours and attaining work for guiding a paper sheet and peeling it from a heating roller. CONSTITUTION: A cleaning pad 13 for cleaning the heating roller 4 is held by a pad holder 12 provided with a paper guiding surface 14 in a tangential direction in the contact part of the heating roller 4 with a pressure roller 5 and constituted so that one end edge 16 of the paper guiding surface 14 is arranged in proximity to the heating roller 4 and the paper sheet 6 is guided with use of the pad holder 12 and peeled from the heating roller 4 by one end edge 16 of the pad holder 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in laser printers, copying machines and the like.

[0002]

2. Description of the Related Art There is a fixing device which transfers a toner image developed on a photoconductor onto a sheet and fixes the transferred image on the sheet by heat and pressure. FIG. 5 shows a conventional fixing device 50. A heater 52 is provided on both sides of the cover 51.
A heating roller 53 having a built-in roller is rotatably provided, and a bearing (not shown) that rotatably supports the pressure roller 54 is urged upward and held vertically movable. With this structure, the pressure roller 54 is pressed against the heating roller 53. Further, the cover 51 is provided with paper guide plates 56, 57, 58 for guiding the paper 55, and a plurality of peeling claws 60 are rotatably held on the inner surface of the wall surface 59 on the paper guide plate 58 side. A plurality of rotation supporting portions 61 are integrally formed. Furthermore, the cover 51
A pad holder 63 for holding a cleaning pad 62, which is made of a soft material such as a sponge that flexes elastically and is pressed against the heating roller 53, is attached to the upper part of the.

In such a fixing device 50, heat and pressure are applied to the paper 55 while the paper 55 on which the toner image on the photoconductor is transferred is discharged by the heating roller 53 and the pressure roller 54. As a result, the transfer image on the paper 55 is fixed. In this case, the paper 55 warps so as to wind around the heating roller 53. In particular, the moistened paper 55 has a surface on the side of the heating roller 53 that dries faster than the side of the pressure roller 54 and tends to warp and wind around the side of the heating roller 53. For this,
The paper 55 is peeled from the heating roller 53 by the peeling claw 60 and discharged. Further, since the toner on the paper 55 adheres to the heating roller 53, the cleaning roller 62 wipes the toner.

Although not shown in the drawing, the actual flat plate 1-1369
As described in Japanese Patent Laid-Open No. 55-55, there is a fixing device in which a cleaner for wiping toner on a heating roller is integrally formed with a peeling claw for peeling a sheet from the heating roller.

[0005]

The fixing device 5 shown in FIG.
0 is the peeling claw 6 in order to stabilize and continue the fixing work.
0 and the cleaning pad 62 supported by the pad holder 63 are independently provided, which increases the number of parts and the number of assembling steps, resulting in an increase in cost.

Further, in the fixing device disclosed in Japanese Utility Model Laid-Open No. 1-136955, the number of parts can be reduced because the peeling claw is formed integrally with the cleaner. However, since the peeling claws protrude, the outer shape of the cleaner becomes a complicated shape having irregularities. When a plurality of peeling claws are arranged, the shape becomes more complicated and it becomes difficult to manufacture a molding die. Furthermore, since the molded product (part that supports the cleaning pad) also has a large number of irregularities, the degree of deformation due to sink marks is large and the part accuracy is reduced. As a result, it is difficult to uniformly bring the plurality of peeling claws closer to or in contact with the heating roller.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a rotatable heating roller, a rotatable pressure roller elastically contacting the heating roller, and a contact portion between the heating roller and the pressure roller. A pad holder having a paper guide surface along the tangential direction, and one end edge of the paper guide surface arranged in proximity to the heating roller; and a pad holder formed of an elastically bendable soft material on the pad holder. The fixing device includes a cleaning pad that is supported and pressed against the heating roller.

[0008]

According to the present invention, the pad holder for supporting the cleaning pad has the paper guide surface, and one edge of the paper guide surface is brought close to the outer periphery of the heating roller, so that the paper guide surface of the pad holder is used. And guide the paper,
The paper can be peeled off from the heating roller at one edge of the pad holder.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a fixing device 1 of this embodiment. That is, a heating roller 4 having a heater 3 therein is rotatably provided on both side surfaces of the cover 2, and a bearing (not shown) for rotatably supporting the pressure roller 5 is urged upward. It is held so that it can move up and down. With this structure, the pressure roller 5 is pressed against the heating roller 4. Further, a paper guide plate 7 for guiding the paper 6 is provided on the cover 2.
8 and 9 are formed, and a thermostat 10 that opens and closes between the heater 3 and a power source according to the temperature detection result of a thermistor (not shown) is provided.

A cleaning unit 11 is mounted on the cover 2. The cleaning unit 11 includes a pad holder 12 made of synthetic resin and a cleaning pad 13 held by the pad holder 12. The cleaning pad 13 is made of a soft material such as sponge that elastically bends. Formed on the lower surface of the pad holder 12 is a paper guide surface 14 facing the paper guide plate 9 at a predetermined interval along the tangential direction at the contact portion between the heating roller 4 and the pressure roller 5. There is. Further, a recess 15 for accommodating the cleaning pad 13 is formed on one end surface of the pad holder 12 on the heating roller 4 side (see FIG. 2). The one end edge 16 of the paper guide surface 14 on the heating roller 4 side (the lower edge of the opening surface of the concave portion 15) is a straight line with its tip protruding like an edge. The one end edge 16 is arranged close to the outer peripheral surface of the heating roller 4 with a gap of about 0.5 to 1 mm. Further, a grip 17 is formed in the center of the pad holder 12, and protrusions 18 are formed on both side surfaces.

Further, as shown in FIGS. 3 and 4, the cover 2 is formed by connecting a pair of divided covers 2a and 2b, and an opening 19 is formed on the back surface thereof. The length of the opening 19 is slightly longer than the lateral length of the pad holder 12 not including the protrusion 18,
The stepped portion 2 is defined to have a length shorter than the length including the protrusion 18 and supports the pad holder 12 from below on both sides of the opening 19.
0 is formed, and the pad holder 12 is provided on the left side of the opening 19.
An elastic piece 21 for pressing the side surface of the right side is provided.

In such a structure, the pad holder 1
The left protrusion 18 is inserted into the opening 19 while inclining 2. Then, the right protrusion 18 is inserted into the opening 19 with the pad holder 12 being moved to the left as much as possible. . In this state, by releasing your hand, the pad holder 1
2 is pressed to the right by the elastic piece 21, and the right protrusion 18
Is kept in a state of wrapping behind the back surface of the cover 2. In this case, the protrusion 18 on the left side is also kept in a state of being wrapped on the back side of the back surface of the cover 2. Therefore, the pad holder 12 is biased by the pressure of the cleaning pad 13 which is pressed against the heating roller 4 and deformed, and the projection 18 is brought into contact with the inner surface of the cover 2 by the biasing force, so that the vertical position of the pad holder 12 is Since the upper and lower sides of the opening 19 are restricted, the mounting position of the pad holder 12 with respect to the cover 2 is determined, and as a result, the position with respect to the heating roller 4 is accurately determined at the edge 16 of the pad holder 12. .

In such a fixing device 1, heat and pressure are applied to the paper 6 in the process of discharging the paper 6 onto which the toner image on the photoconductor is transferred by the heating roller 4 and the pressure roller 5. As a result, the transferred image on the sheet 6 is fixed.
In this case, the paper 6 may warp so as to wind around the heating roller 4, but is peeled from the heating roller 4 by the one edge 16 of the pad holder 12, and the paper guiding surface 14 of the pad holder 12 and the paper guiding of the cover 2 are guided. It is guided by the surface 9 and discharged. Further, since the toner on the paper 6 adheres to the heating roller 4, the cleaning pad 13 wipes the toner.

As described above, since the pad holder 12 supporting the cleaning pad 13 can be used to guide the paper 6 in the paper discharge direction and peel the paper 6 from the heating roller 4, the number of parts and the number of assembling steps can be reduced. It is possible to reduce it. In addition, one edge 16 of the pad holder 12
Has a very simple shape and has no irregularities, so that the structure of the molding die for molding the pad holder 12 can be simplified. Further, since the formed pad holder 12 has a shape with less unevenness, it is possible to form the pad holder 12 with an accurate dimension with less deformation due to sink marks after the molding.

[0015]

According to the present invention, the pad holder for supporting the cleaning pad has a paper guide surface, and one edge of the paper guide surface is brought close to the outer circumference of the heating roller. The paper can be guided, and the paper can be separated from the heating roller at one edge of the pad holder. Therefore, the number of parts and the number of assembling steps can be reduced, and one end of the pad holder that separates the paper from the heating roller can be reduced. Since the shape of the edge is extremely simple and there are no irregularities, the structure of the molding die that molds the pad holder can be simplified.Furthermore, the molded pad holder has a shape with few irregularities, There is little deformation due to sink marks afterwards, and molding can be performed with accurate dimensions.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a pad holder and a cleaning pad.

FIG. 3 is an exploded perspective view showing the mounting relationship of the cleaning unit with respect to the cover of the fixing device.

FIG. 4 is a rear view showing the mounting relationship of the cleaning unit with respect to the cover of the fixing device.

FIG. 5 is a vertical sectional side view showing a conventional fixing device.

[Explanation of symbols]

 4 Heating Roller 5 Pressure Roller 12 Pad Holder 13 Cleaning Pad 14 Paper Guide Surface 16 One Edge

Claims (1)

[Claims] 1. A rotatable heating roller, a rotatable pressure roller elastically contacting the heating roller, and a paper guide surface along a tangential direction at a contact portion between the heating roller and the pressure roller. And a pad holder whose one end edge of the paper guide surface is arranged close to the heating roller and a soft material that elastically bends and is supported by the pad holder and pressed against the heating roller. A fixing device comprising a cleaning pad and a cleaning pad.