JPH03177873A - Fixing device - Google Patents

Abstract

PURPOSE:To maintain a fixing operation stable over a long period of time with simple and inexpensive constitution by providing an elastic member for peeling which presses its front end to a heating roller and peels the material to be foxed past the spacing between the heating roller and a pressurizing roller from the heating roller. CONSTITUTION:The elastic member 57 for peeling which presses its front end to the heating roller 41 and peels the material P to be fixed past the spacing between the heating roller 41 and the pressurizing roller 42 from the heating roller 41 is provided. The material P to be fixed is peeled from the heating roller 41 by the elastic member 57 for peeling which is pressed to the heating roller 41 by the elastic force possessed by the member itself. The constitution is simplified in this way and the number of parts is decreased; in addition, the assembling characteristic is improved and the cost is reduced. Problems, such as wear, are eliminated and the fixing operation stable over a long period of time is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a fixing device applied to an image forming apparatus such as a copying machine or a laser printer.

(Prior Art) In recent years, image forming apparatuses such as copying machines and laser printers have been made smaller, and fixing devices used therein have also been made smaller.

Usually, this type of fixing device is a heating roller type that includes a heating roller for melting and fixing a powder image onto a fixing material, and a pressure roller that presses the fixing material against the heating roller. A fixing device is used.

Conventionally, in this type of heating roller type fixing device, in order to prevent the material to be fixed from being wrapped around the heating roller, the tips of a plurality of resin peeling claws are pressed against the heating roller by the biasing force of a spring. The fixing material is peeled off from the heating roller.

(Problem to be Solved by the Invention) As described above, in the conventional fixing device, the material to be fixed is removed by pressing the resin peeling claw against the surface of the heating roller, so it is possible to remove the material to be fixed in a relatively short period of time. The peeling nail is worn out,
There was a problem that good fixing operation could not be maintained for a long period of time.

In addition, each peeling claw must be rotatably supported, and a spring must be connected to each peeling claw, resulting in a complicated structure and a large number of parts, as well as poor assembly and high costs. was there.

The present invention has been made to solve the above problems, and its purpose is to provide a simple and inexpensive configuration, while providing a simple and inexpensive configuration.
It is an object of the present invention to provide a fixing device that can maintain stable fixing operation over a long period of time.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a heating roller for melting and fixing a powder image onto a material to be fixed, and a heating roller for melting and fixing a powder image onto a material to be fixed. In a fixing device comprising a pressure roller that presses a material, a peeling device that brings the tip of the material into contact with the heating roller and peels the material to be fixed that has passed between the heating roller and the pressure roller from the heating roller. It is equipped with an elastic member.

(Function) That is, according to the present invention, the material to be fixed can be peeled off from the heating roller by the peeling elastic member that comes into contact with the heating roller using its own elastic force. Further, the elastic member for peeling may be a plate spring or the like, and its attachment may be by welding or the like. As a result, compared to the conventional method in which the peeling claws are rotatably supported and a spring is connected to each peeling claw, the structure is simpler and the number of parts is reduced, and it is possible to improve assembly efficiency and reduce costs. In addition to being able to reduce the amount of heat, the problem of wear can also be eliminated, making it possible to maintain stable fixing operation over a long period of time.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 2 shows the internal structure of a laser printer that employs the fixing device of the present invention, and numeral 1 in the figure is the main body of the device. At the bottom of the device main body 1, there are a plurality of function-added control boards (
(not shown) and a control board accommodating section 3 for accommodating the main control board 2, and above the control board accommodating section 3, an electrophotographic process unit 4 for forming an image is arranged. . Further, a paper feed cassette 5 is installed on the right side of the apparatus main body 1, and a paper ejection section 6 is formed in the upper part of the apparatus main body 1.

Further, the image forming process unit 4 has the following configuration.

That is, a drum-shaped photoreceptor 20 serving as an image carrier is disposed approximately at the center of a unit storage section in the apparatus main body 1. The photoreceptor 2o is surrounded by scorotrons along its rotation direction. lj) The electric means 21, the exposure section 22a of the laser exposure unit 22 as an electrostatic latent image forming means, the developing unit 23 as a developing means, the transfer means 24 consisting of a scorotron, the cleaning means 25, and the pre-exposure means 26 are each sequentially It is arranged.

Further, 27 is a paper conveyance path formed in the main body 1 of the apparatus,
The paper P as a fixing material fed from the paper feed cassette 5 via the paper feed means 28 is discharged through the image transfer section 29 between the upper side of the photoreceptor 20 and the lower side of the transfer means 24. It is designed to lead to the paper section 6.

A pair of aligning rollers 30 is arranged on the upstream side of the image transfer section 29 of the paper transport path 27, and on the downstream side thereof, a fixing device 35, which will be described later, a transport direction switching gate 36,
A pair of paper ejecting rollers 37 as a paper ejecting means are also arranged.

When a print start signal is received from a host system (not shown), the photoreceptor 20 rotates and the photoreceptor 20 rotates.
0 is uniformly charged by the charging means 21. Next, the laser beam a modulated in response to the dot image data from the host system is scanned and exposed onto the photoconductor 20 using the laser exposure unit 22, thereby creating an electrostatic charge corresponding to the image signal on the photoconductor 20. Form a latent image. This electrostatic latent image on the photoreceptor 20 is developed and visualized using powder (toner) t in the developing unit 23.

On the other hand, in accordance with the toner image forming operation, the paper P taken out from the paper feed cassette 5 is transferred to the aligning roller pair 3.
0, a toner image, which is a powder image, previously formed on the photoreceptor 20 is transferred onto the paper P by the action of the transfer means 24.

The transferred paper P passes through the paper conveyance path 27 and is sent to the fixing device 35, and after the toner image is melted and fixed on the paper P, it passes through the switching gate 36 and is transferred to the paper ejection roller pair 37. The paper is guided and discharged to a paper discharge section 6.

Further, residual toner remaining on the photoreceptor 20 after the toner image is transferred onto the paper P is removed by the cleaning means 25.

Further, as shown in FIG. 1, the fixing bag @35 has a configuration including a heating roller 41 having a built-in heater lamp 40, and a pressure roller 42 pressed against the lower side of the heating roller 41. ing. And these rollers 41.42
By passing a sheet of paper P, which is a material to be fixed, between them, the toner images t... are melted and fixed on the sheet of paper P.

Further, the pressure roller 42 is surrounded by a lower casing 47 to which a population guide 45 and a paper discharge guide 46 are attached. Further, the heating roller 41 is surrounded by an upper casing 49 to which a paper discharge guide 48 is attached. Reference numeral 50 denotes an artificial guide consisting of a bent portion of the upper casing 49.

And the lower casing 47 and the upper casing 49
This prevents the temperature inside the fixing device 35 from leaking to the outside as much as possible.

Further, a thermistor 55 as a temperature detector is provided in contact with the heating roller 41 to detect the surface temperature, and the surface temperature of the heating roller 41 is adjusted according to the detection result. The heater lamp 40 inside the heating roller 41 is turned on so that the required temperature is always maintained.
"Off" control is provided.

Further, as shown in FIG. 3, the paper ejection guide 48 includes:
Ribs 56 are provided at appropriate intervals on the guide portion 48a on the lower surface side.
In addition, on the upper surface 48b side, there are a plurality of peeling leaf springs 57 whose surfaces are coated with a heat-resistant and wear-resistant coating, such as PFA (Teflon), as a plurality of peeling elastic members. Welded at appropriate intervals.

These peeling leaf springs 57 have their tips brought into contact with the surface (circumferential surface) of the heating roller 41 due to their own elastic force.

As shown in FIG. ... is peeled off from the surface of the heating roller 41, and then guided by the guide portion 48a of the paper ejection guide 48 in the direction ♂M♂H from the heating roller 41. In this way, wrapping of the paper P around the heating roller 41 is prevented.

As a result, compared to the conventional method in which the peeling claws are rotatably supported and a spring is connected to each peeling claw, the structure is simpler and has fewer parts, and it is easier to assemble. This makes it possible to reduce costs by J-performance, eliminate the problem of wear, and maintain stable fixing operation over a long period of time.

Note that the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the present invention, the material to be fixed can be peeled off from the heating roller by the peeling elastic member that comes into contact with the heating roller using its own elastic force. Further, the elastic member for peeling may be a plate spring or the like, and its attachment may be by welding or the like. As a result, compared to the conventional method in which the peeling claws are rotatably supported and a spring is connected to each peeling claw, the structure is simpler and the number of parts is reduced, and it is possible to improve assembly efficiency and reduce costs. In addition to making it possible to reduce
It is possible to eliminate the problem of wear, and it is possible to provide a fixing device that can maintain stable fixing operation over a long period of time.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic side view showing the main parts of the present invention, FIG. 2 is an internal configuration diagram of a laser printer employing the fixing device of the present invention, and FIG. The figure is a bottom view of the main part. 35...Fixing device, 41...Heating roller, 42...
・Pressure roller, 57...Elastic member for peeling (plate spring for peeling) P...Fixing material (paper)...Powder (toner)

Claims (1)

[Claims] A heating roller for melting and fixing a powder image onto a fixing target material;
In the fixing device including the heating roller and a pressure roller that presses the material to be fixed, the material to be fixed that has passed between the heating roller and the pressure roller is brought into contact with the leading end of the heating roller. A fixing device comprising a peeling elastic member that peels off from a heating roller.