JPS597390B2 - Fusing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roller fixing device in a recording apparatus such as a copying machine.

2. Description of the Related Art In a recording apparatus such as a copying machine, a roller fixing device is well known in which a copy sheet having a toner image formed on its surface is passed between a pair of fixing rollers, thereby fixing the copy paper.

(For example, see Japanese Utility Model Application Publication No. 50-10248.) Examples of the roller fixing device include a pressure roller fixing device in which copy paper on which a toner image is formed is passed between fixing rollers that are pressed against each other, and a pressure roller fixing device that passes a copy paper on which a toner image is formed between fixing rollers that are pressed against each other. A heated roller fixing device is generally known in which copy paper is passed through and fixed by the action of heat.

In this case, in any type of roller fixing device,
Since there is a risk that the copy paper sent between the pair of rollers may stick to the fixing roller and get wrapped around it, a copy paper separation claw is provided on the copy paper delivery side of the pair of fixing rollers to separate the copy paper that has stuck to the roller. That's what I do.

FIG. 1 is a diagram showing an example of a conventional roller fixing device equipped with separation claws. In FIG. 1, an upper measuring roller 1 and a lower measuring roller 2, which are in pressure contact with each other, are rotated in the directions of arrows, and copy paper 3 on which a toner image has been formed is rotated.
The powder image formed on the surface of the powder image is fixed when the copy paper 3 passes between the rollers 1 and 2. When the copy paper 3 sent out from the rollers 1 and 2 is wrapped around the rollers 1 and 2, it is peeled off by separating claws 4 and 5 provided on the copy paper delivery side. in this case,
Each of the separation claws 4 and 5 is fixedly supported so as to be in contact with the fixing rollers 1 and 2 with a constant pressure. Fixing rollers 1 and 2
Because the surface of the surface is required to have mold releasability, heat resistance, etc. due to its use, there are limitations on the materials it can be made of, and coatings of polytetrafluoroethylene (generally known as Teflon), silicone rubber, etc. are used. , coated on the metal roll surface.

Furthermore, it is well known to apply an anti-offset liquid such as silicone oil to the surface of the fixing roller to assist and improve its release properties.

Recent recording devices such as copying machines are capable of selectively producing copies on two or more types of copy paper of different sizes with a single device.
In the roller fixing device of a copier that can copy onto m0 and B4 size (257 x 364 m7n) copy paper, when applying silicone oil to the fixing roller, the application width is the width of the large size copy paper, that is, the B4 size copy paper. Equally, coating with this width is always performed regardless of the size of the copy paper. Note that the copy paper is fed so that the longitudinal direction of the copy paper is parallel to the traveling direction of the copy paper, and hereinafter the length of the copy paper in the direction perpendicular to the traveling direction of the copy paper is referred to as the width. Therefore, according to the above-mentioned conventional fixing device, when fixing A4 size copy paper, excess silicone oil is applied to the roller by an amount corresponding to the difference in width between A4 size and B4 size copy paper. If the separating claw remains in contact with this part, silicone oil will accumulate on the claw and fall, causing contamination inside the machine.Furthermore, it will prevent the fixing of B4 size copy paper. When performing this, the roller part that has been coated with this extra silicone oil should be
Furthermore, as oil is applied, the amount of oil becomes excessive, and the excess adheres to and accumulates on the separating claw, falling as drips, contaminating the inside of the copying machine, or transferring to B4 size copy paper. It has the disadvantage that it adheres and causes stains.

An object of the present invention is to provide a fixing device that eliminates these drawbacks.

The present invention will be explained below with reference to embodiments shown in the drawings. In order to solve the above-mentioned problems, the present invention provides a roller fixing device equipped with a means for applying an anti-offset liquid, in which a separating claw for separating copy sheets that comes into contact with the roller surface is used to separate large-sized copy sheets (B4 size in the embodiment). A small-sized copy paper (A4 size in the example) that is within the width of a large-sized copy paper.
The separating claw is positioned outside the width of the roller and within the width of the small size copy paper for small size copy paper, and has means for moving the separating claw in the longitudinal direction of the roller according to the size of the copy paper. This is a fixing device.

2 to 4 show one embodiment of the present invention, and FIG. 4 is a partially detailed view of FIG. 3. The fixing roller 11 has a thin Teflon coating 11b on the surface of a metal pipe 11a, and a halogen motor 13 is disposed inside. The pressure roll 12 is made of a metal roller 12a coated with a silicone rubber layer 12b, and rotates in the direction of the arrow in cooperation with the fixing roller 11 while being in pressure contact with the fixing roller 11. Three separation claws arranged in the longitudinal direction of the roller 1
5, 16, and 17 are arranged, and the separating claw 15 is located at the part A (FIG. 3) which is the separation reference end part of the copy paper of each size, and is swingable on the shaft 18. The fixing roller 11 is pressed against the fixing roller 11 with a constant pressure by a spring 19. The separation claw 16 is located at part B, which is one end of the A4 size copy paper (the end opposite to the separation reference end), and the separation claw 17 is similarly located at part C, one end of the B4 size copy paper. .

The separation claws 16 and 17 share a shaft 20 supported parallel to the longitudinal direction of the rollers 11 and 12, and the separation claw 16 is fixed at the position of the B section. The separation claw 17 is held on bearings 23 and 24 made of a material with good sliding properties, and is attached to the shaft 20,
The fixing roller 11 is supported by a support member 22 that can move on the fixing roller 21 in parallel to the longitudinal direction of the fixing roller 11 . The rotary solenoid 25 is connected to the shaft 27 of the support member 22 through a link 26, and when copying onto B4 size copy paper, the rotary solenoid 25 is connected to the shaft 27 of the support member 22 through a link 26. Separation claw 1
5, 16, and 17 are located, but when copying to A4 size copy paper, which is narrower in width than B4 size copy paper, the rotary solenoid 25 is automatically activated in response to the copy paper size switching signal. It turns on and starts rotating, and the link 26 converts the rotation into a linear motion of the separating claw 17, and the separating claw 17 moves from the C section to the C' section, which is within the width of the A4 size and close to one end thereof. do. While the A4 size copy paper is being passed through, it is held at its position (C), which eliminates the problem of oil adhering to the separating claw 17 in the excess application area. In order to remove the oil present in the part itself, as shown in FIG. If the excess oil is removed from the roller circumferential surface before the process, more complete removal of excess oil can be achieved.

Preferably, the lower roller 12 is provided with a similar cleaning member 32.

Further, in synchronization with the copy end signal, the rotary solenoid 25 is turned off, and a return spring of the solenoid 25 itself or a return spring is installed on the shaft 20 or 21 to move the separation claw 17 to the C section. Move and return.

By using such a movable claw 17, the fixed claw 1 shown in the figure
5 and 16 (particularly 16) may be omitted to provide a simple separation device.

Other methods for moving the separating claws 17 in the longitudinal direction of the roller include a method of holding a female threaded separating claw on a male threaded shaft and rotating the shaft to move the separating claw;
Alternatively, it is also effective to connect a metal wire or the like to the separation claw and move the separation claw by winding up the wire.

As described above, the present invention moves the claw member that separates the copy paper from the fixing roller in the axial direction of the roller and holds it within the paper width of the corresponding copy paper in accordance with the size change of the copy paper used. Then, the separation claw slides into the area where excess anti-offset liquid is applied and causes the liquid to accumulate, and the size is changed to eliminate causes of contamination such as adhesion of the anti-offset liquid when using large paper sizes. There is an effect that can be achieved.

Furthermore, by introducing the above-mentioned movable claw, it is no longer necessary to arrange multiple separation claws for each of the various paper sizes, and by using one separation claw by moving it in the axial direction, The entire structure of the separation claw can be simplified and the cause of paper feeding problems can be eliminated.

In addition, by using a very small number of separating claws (theoretically only one is enough) in this way, there is very little concern that a large number of separating claws will constantly be in sliding contact with the surface of the fixing roller, causing the surface of the fixing roller to wear out in a distorted manner. . Conventionally, a device is known in which the separation claw is continuously moved in parallel in the axial direction with the rotation of the fixing roll (Japanese Utility Model Publication No. 52-39148). An apparatus configured to move the installation location of the apparatus and achieve the various effects described above is essentially different from the technology described in such conventional apparatuses.

[Brief explanation of the drawing]

FIG. 1 is a side view of a conventional roller fixing device equipped with separation claws, FIG. 2 is a side view of a fixing device according to the present invention, FIG. 3 is a plan view thereof, and FIG. 4 is a perspective view thereof. 11, 12... Fixing roller, 3...
Copy paper, 30...Offset prevention liquid application means,
17...Movable separation claw.

Claims (1)

[Claims] 1. A pair of fixing rollers that cooperate with each other to fix a toner image on copy paper, means for applying an anti-offset liquid to at least one of the pair of fixing rollers, and a separation claw that separates the copy paper from the roller surface. In a fixing device for fixing toner images on two or more types of copy paper of different sizes, the separating claw is set within the width of the large copy paper and for the small size copy paper. The separating claw is positioned outside the width of the copy paper for small-size copy paper, and within the width of the small-size copy paper for small-size copy paper, and has means for moving the separating claw in the longitudinal direction of the roller according to the copy paper size. A fixing device characterized by: