JPH0532857Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a method in which an unfixed image formed on a recording material (hereinafter referred to as a transfer sheet) by electrophotography or the like is brought into contact with each other under pressure. This invention relates to a pressure fixing device that fixes the transfer sheet under pressure by passing the transfer sheet between a pair of rotating rollers.

[Prior art]

Conventionally, the pressure means of this type of fixing device is as shown in FIG.
It was configured as shown in b. 1 is the pressure shaft, 2
is a pressure nut, 3 is a pressure spring seat (top), 4 is a pressure spring, 5 is a pressure spring seat (bottom), 6 is an upper plate that supports the fixing roller, and 7 is a bottom that supports the lower fixing roller. This is the side plate.

In such a configuration, the pressure spring is buckled or deformed as shown in FIGS. 2a and 2b due to the inclination of the cowling portion of the pressure shaft 1 of the upper plate 6 and the lower plate 7. Also, uneven contact occurs between the pressure spring seat (upper) 3 and the nut 2, and uneven contact between the pressure spring seat (lower) 5 and the upper plate 6 occurs. Furthermore, uneven contact between the pressure shaft 1 and the lower plate 7 (at the portion 8) occurs, and buckling and deformation of the pressure shaft 1 itself occurs.

Due to the above-mentioned factors, the pressure and pressure distribution between the rollers, which are the most important in a pressure fixing device, become a factor that fluctuates, and when fixing to a transfer sheet, there are drawbacks that cause fusing failure. Had to have.

[Purpose of invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure fixing device that eliminates the drawbacks of the prior art described above and also improves the durability of the pressure means of the pressure fixing device.

[Summary of the idea]

To achieve the above object, the present invention includes a pair of fixing rollers, an upper plate and a lower plate that respectively support the rollers, a pressure shaft for pressurizing the upper plate and the lower plate, a pressure spring, and a spring force. In the pressure fixing device, the upper plate and the lower plate are provided with a U groove along the longitudinal direction of the roller, and the spring seat and the pressure shaft are provided with an alignment part along the longitudinal direction of the roller. The centering part is engaged with the centering part to apply pressure between the upper and lower side plates.

〔Example〕

FIG. 1 shows a side view of a pressure fixing device according to an embodiment of the present invention. 1 is a pressure shaft, 2 is a pressure nut, 3 is a pressure spring seat (top), 4 is a pressure spring, 5 is a pressure spring seat (bottom), 6 is an upper side plate, 7 is a lower side plate, 9 is a Rotating axis, 1
0 is an upper fixing roller, and 11 is a lower fixing roller.

In the above configuration, by tightening the pressure nut 2, the upper fixing roller 10 supported by the upper plate 6 and the lower fixing roller 11 supported by the lower plate 7 are rotated about the rotating shaft 9. The pressure is applied by the pressure spring 4.

The pressure spring seat (lower) 5 has a semicircular protrusion (alignment part) shown in 5a, contacts the U groove 6a provided in the upper plate 6, and slides through the lubricant. It's becoming possible.

The pressurizing shaft 1 similarly has a semicircular protrusion (alignment part) shown in 1a, contacts the U groove 7a provided in the lower plate 7, and is made slidable via lubricant. There is.

With the above configuration, the fixing rollers 10, 11 can be stably applied by the pressure spring 4 without being affected by the inclination of the upper plate 6 or the lower plate 7, as shown in FIGS. 3a and 3b. can be supplied to

In addition, FIG. 4 is a cross-sectional view of the pressurizing means of this configuration, and FIG.
In the figures, a and b show the shape of the protrusion (alignment) of the pressure spring seat (lower) 5, and FIGS. 6a and b show the shape of the protrusion (alignment) of the pressure shaft 1. .

As is clear from these figures, the U-groove and the protrusion are provided along the longitudinal direction of the fixing roller.

Therefore, the pressure is dispersed in the longitudinal direction of the roller, and even if the roller receives a strong pressing force, the groove portion and alignment portion will not be damaged.

[Effect of idea]

As explained above, by aligning the pressure spring seat and the pressure shaft, the pressure spring seat and the pressure shaft can slide, the pressure shaft and the pressure spring are always kept parallel, and the pressure spring is aligned. This has the effect of stably applying pressure to the pressure roller.

This configuration also suppresses buckling and deformation of the pressure spring and pressure shaft, and prevents partial contact (contact on only one side) between the pressure spring seat and the upper plate, and between the pressure shaft and the lower plate. This eliminates scratches and scrapes caused by contact between parts.

Therefore, from these reasons, pressure means (pressure spring,
This has the effect of improving the durability of the pressure shaft, pressure spring seat, upper plate, and lower plate.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the pressure fixing device of the present invention, FIGS. 2a and 2b are schematic diagrams showing a conventional example of the pressure means of the pressure fixing device, and FIGS. b is a schematic explanatory diagram explaining the action of the present invention, Fig. 4 is a cross-sectional view of the pressure means, and Figs. 5a and 5b are the shapes of the protrusion (alignment part) of the pressure spring seat (lower). FIGS. 6a and 6b are a top view and a side view showing the shape of the protrusion (alignment part) of the pressurizing shaft. 1 is a pressure shaft, 2 is a pressure nut, 3 is a pressure spring seat (top), 4 is a pressure spring, 5 is a pressure spring seat (bottom), 6
1 is an upper plate, 7 is a lower plate, 9 is a rotating shaft, 10 is an upper fixing roller, and 11 is a lower fixing roller.

Claims (1)

[Claims for Utility Model Registration] A pair of fixing rollers, an upper plate and a lower plate supporting the rollers, a pressure shaft for pressurizing the upper plate and the lower plate, a pressure spring, and a spring force. In the pressure fixing device, the upper plate and the lower plate have a U along the longitudinal direction of the roller.
A pressure fixing device characterized in that a groove is provided in the spring seat and the pressure shaft with an alignment part along the longitudinal direction of the roller, and the U groove and the alignment part are engaged to apply pressure between the upper and lower side plates.