JPH112980A - Image fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image fixing device capable of preventing the damage of a pressure belt by suppressing its meandering, at a low cost. SOLUTION: This device is provided with a holding roller 18 having a groove in the end part, the pressure belt 19 having both end parts 19a formed into wedge shapes, a projecting part 21b fitted into the groove, wedge parts 21a engaged with both end parts of the belt 19 and an extension part 21c overlapped with the end part side of a pressure roller. At this time, a flange 21 whose hardness is higher than that of the belt 19 is used and further, the belt 19 and the flange 21 are pressed by a roller 22, to prevent the meandering of the belt 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image in which an electrostatic latent image formed on a photoreceptor is visualized with toner particles, transferred to a recording sheet, and then fixed on the recording sheet by heat and pressure. The present invention relates to a fixing device.

[0002]

2. Description of the Related Art FIG. 4 is a schematic configuration diagram of a conventional image forming apparatus, and FIG. 5 is a schematic configuration diagram of a conventional fixing device. In FIG. 4, reference numeral 1 denotes an L including a light source such as a semiconductor laser, a collimator lens, a rotating mirror, and an f-θ lens, and an optical system.
The SU unit 3 is a photoreceptor having a photosensitive receiving layer such as a selenium-based photoreceptor or an organic photoreceptor applied in a thin layer on the outer periphery of a belt-shaped polyethylene terephthalate or the like as a base material. And the driven roller 4 to rotate in the direction of arrow a.

[0005] 5Y, 5M, 5C, and 5B are developing units disposed to face the photosensitive member 3, and contain yellow, magenta, cyan, and black toners, respectively. Reference numeral 6 denotes a drum-shaped intermediate transfer member to which a transfer voltage is applied, and rotates in the direction of arrow b. Intermediate transfer member 6 and photoconductor 3
Are in contact with each other, and the toner image formed on the photoconductor 3 is transferred onto the intermediate transfer body 6. Of the second transfer unit, 7
Is a second transfer belt for transferring the toner image formed on the intermediate transfer member 6 onto the recording paper, and comes into contact with the intermediate transfer member 6 when the toner image is transferred onto the recording paper (second transfer). . Reference numeral 8 denotes a charger for supplying a voltage necessary for the second transfer. Reference numeral 9 denotes a paper feeding unit for storing the recording paper, which feeds the recording paper to the second transfer unit as appropriate.

In FIG. 5, reference numeral 10 denotes an image fixing device, 11 denotes a metal hollow heating roller whose surface is coated with a silicon rubber 12 or the like, and a heater 13 such as a halogen lamp is disposed inside. ing. 14 is
It is a pressure belt of silicone rubber 12 and holding roller 1
5a, 15b and the heating roller 1
It is wrapped around and in pressure contact with 1. 16 is the heating roller 1
1 is a temperature detector for detecting the surface temperature. By adjusting the output of the heater 13 with a heater driver based on the temperature detected by the temperature detector 16, the heating roller 11
To keep the surface temperature constant. In FIG. 4, 1
Reference numeral 7 denotes a paper discharge roller.

[0005] The operation of the image forming apparatus using the conventional image fixing device configured as described above will be described below. According to the print signal, the LSU unit 1 sends the photoconductor 3
A latent image corresponding to a component of a first color (hereinafter, referred to as yellow) is written on the top. This latent image is visualized by a developing device 5Y containing yellow toner. Then, the visualized toner image of one color is transferred onto the intermediate transfer body 6.

Similarly, the magenta, cyan, and black toner images sequentially formed on the surface of the photosensitive member 3 are also transferred onto the intermediate transfer member 6, and one composite toner image is formed on the intermediate transfer member 6. You. Thereafter, the recording paper is supplied from the paper supply unit 9 and is conveyed to the second transfer unit. In the second transfer section, the toner image on the intermediate transfer body 6 is transferred to a recording sheet by the charger 8 and is conveyed to the image fixing device 10. The recording paper carrying the unfixed image passes between the heating roller 11 and the pressure belt 14 in the image fixing device 10.

At this time, the synthetic toner image is melted by contact with the heating roller 11, and
The composite toner image is semi-permanently fixed on the recording paper by being pressed against the pressure belt 14. The recording paper is conveyed from the image fixing device 10 to a paper discharge roller 17 and discharged outside.

[0008]

However, depending on the assembling accuracy, the plurality of rollers of the holding rollers 15a and 15b and the heating roller 11 do not become parallel, and therefore, while the fixing operation is continued, the pressure belt 14 is not moved. Are shifted in the thrust direction, and belt meandering occurs. As the belt meanders, the end of the pressure belt 14 comes into contact with another member in the vicinity and is broken.

In order to prevent the belt from meandering, a method has been adopted in which flanges are provided at the ends of the holding rollers 15a and 15b to suppress the end of the pressure belt. But the effect was not enough. Further, there is a method of forming a bead that fits with the holding rollers 15a and 15b on the pressure belt 14, but there is a drawback that processing is very difficult and cost is increased.

Accordingly, an object of the present invention is to provide an image fixing device capable of suppressing belt meandering and preventing damage to a pressure belt at low cost.

[0011]

SUMMARY OF THE INVENTION The present invention comprises a plurality of holding rollers, an endless pressing belt stretched over the holding rollers, and a heating roller which is in circumferential contact with the pressing belt and heats recording paper. An image fixing device having a holding roller having a groove at an end thereof, both ends of a pressure belt being formed in a wedge shape, and a wedge portion engaging with an end of the pressure belt and a groove of the holding roller. And a flange having a hardness higher than that of the pressure belt having a protrusion fitted to the holding belt and an extension protruding toward the end of the holding roller.

With this configuration, it is possible to realize an image fixing device that can suppress belt meandering and prevent damage to the pressure belt at low cost.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a heating roller according to a first embodiment of the present invention; Wherein the holding roller has a groove at an end thereof, both ends of the pressure belt are formed in a wedge shape, and a wedge portion engaging with an end of the pressure belt and the holding roller are provided. And a flange having a hardness higher than that of the pressure belt having a projection fitted into the groove and an extension protruding toward the end of the holding roller.

According to this configuration, since the thrust of the pressure belt is received by the flange and the flange is held by the groove of the holding roller, meandering of the pressure belt can be prevented. Further, by forming the portion where the flange and the end portion of the pressure belt engage with each other in a wedge shape, the pressure belt can be prevented from running on the flange. Further, since the flange has the extension, it is possible to prevent the flange from being turned up by the thrust force from the pressure belt.

According to the second aspect of the present invention, the angle of the wedge-shaped tip is 40 to 60 °.

According to this structure, the working of the pressing belt and the flange is facilitated, the pressing belt is prevented from running on the flange, and at the same time, the effective fixing width of the pressing belt can be sufficiently ensured. .

According to the third aspect of the present invention, the outer peripheral surface of the pressure belt and the flange is made the same plane, and the outer peripheral surface is pressed against the holding roller by rollers.

According to this configuration, since the pressure belt and the flange are suppressed by the rollers, it is possible to more reliably prevent the pressure belt from running on the flange.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the first embodiment will be described. Here, FIG. 1 is a cross-sectional view of the pressure belt and the flange according to Embodiment 1 of the present invention. Here, the same reference numerals are given to the same components as in the conventional example, and the description is omitted.

In FIG. 1, reference numeral 18 denotes a holding roller having a groove at an end. Reference numeral 19 denotes a pressure belt made of silicone rubber, and as shown in FIG.
a, 18b and the heating roller 11
It is wrapped around and pressed. Both ends 1 of pressure belt 19
9a has a wedge shape. Reference numeral 20 denotes a flange, which is a wedge portion 20 that engages with both ends of the pressure belt 19.
a, a protrusion 20b fitted into the groove of the holding roller 18, an extension 20c overlapping the end of the holding roller 18
have.

With this configuration, even when a thrust force, which is a cause of meandering of the pressure belt 19, is generated, both ends 19
a tries to get under the wedge part 20a,
The pressure belt 19 does not run on the flange 20. Also, a projection 20b fitted into the groove of the holding roller 18
Can support the thrust force because it is fitted in the groove of the holding roller 18. The flange 20 tends to rotate due to the thrust force from the pressure belt 19, but is supported by an extension 20 c overlapping the end of the holding roller 18. Therefore, even when the thrust force is large, the pressing belt 19 can be held without the flange 20 being turned up.

Also, both end portions 19a and wedge portions 20a
When the angle is small, it is difficult to form the wedge shape, and at the same time, the wedge shape becomes longer in the axial direction of the holding roller 18, so that the effective width of the pressure belt 19 becomes shorter. Conversely, if it is too large, the pressure belt 19 will easily ride on the flange 20 due to belt meandering. Therefore, the wedge tip angle is set to 40 to 60 °.

Next, FIG. 2 is a sectional view of a pressure belt, a flange, and rollers according to Embodiment 2 of the present invention, and FIG. 3 is a schematic configuration diagram of an image fixing device according to Embodiment 2 of the present invention. In the present embodiment, as shown in FIG.
1 is set to the same height as the pressure belt 19. Reference numeral 22 denotes a roller, which is in circumferential contact with the overlapping portion between the pressure belt 19 and the flange 21 to move the pressure belt 19 to the holding roller 1.
Press on 8.

With this configuration, when belt meandering occurs, not only the flange 21 but also the rollers 22
Preventing the pressure belt 19 from running on the flange 21;
The thrust force that causes the rotation of the flange 21 is
The rotation of the flange 21 can be more reliably prevented by receiving even the number 2.

[0025]

According to the present invention, even if the mounting accuracy of the holding roller and the heating roller is poor and there is a factor that the pressing belt meanders, the pressing belt can be meandered at low cost and reliably by the flanges and rollers. Can be prevented, and damage to the belt end can be avoided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pressure belt and a flange according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a pressure belt, a flange, and rollers according to Embodiment 2 of the present invention.

FIG. 3 is a schematic configuration diagram of an image fixing device according to a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional image forming apparatus.

FIG. 5 is a schematic configuration diagram of a conventional fixing device.

[Explanation of symbols]

 18 Holding roller 19 Pressure belt 19a Both ends 20, 21 Flange 20a, 21a Wedge portion 20b, 21b Projection 20c, 21c Extension 22 Roller

Claims (3)

[Claims] 1. An image fixing apparatus comprising: a plurality of holding rollers; an endless pressing belt stretched over the holding rollers; and a heating roller which is in circumferential contact with the pressing belt and heats a recording sheet. The holding roller has a groove at an end thereof, and both ends of the pressure belt are formed in a wedge shape, and a wedge portion engaging with an end of the pressure belt and a groove of the holding roller are formed. An image fixing device comprising: a flange having a hardness higher than that of the pressure belt having a fitting portion to be fitted and an extension projecting toward the end of the holding roller. 2. The wedge-shaped tip has an angle of 40 to 40.
2. The image fixing device according to claim 1, wherein the angle is 60 [deg.]. 3. The image fixing device according to claim 1, wherein an outer peripheral surface of the pressure belt and the flange are formed on the same plane, and the outer peripheral surface is pressed against the holding roller by rollers.