JPH0816018A - Fixing apparatus - Google Patents

Abstract

PURPOSE:To provide a fixing apparatus in which oil stain formation in a transfer material can be prevented surely without deteriorating the separating function of the transfer material. CONSTITUTION:Regarding a fixing apparatus which has a pair of heat rollers (a fixing roller 1 and a pressing roller 2) and an upper separating claw 6 and a lower separating claw 7 (separating members) touching the fixing roller 1 and the pressing roller 2, respectively and which fixes a toner image (t) to a transfer paper P by leading the transfer paper P carrying an unfixed toner image (t) between the fixing roller 1 and the pressing roller 2, a cleaning means 13 to clean the lower separating claw 7 is installed in the fixing apparatus. Consequently, since an oil of a mold releasing agent accumulated in the lower separating claw 7 is cleaned and removed by the cleaning means 13, the oil is prevented from penetrating a following transported transfer paper P even if the tip and rear end of the transfer paper P rubs the lower separating claw 7 and thus oil stain formation in the transfer paper P is surely prevented. Moreover, since the upper separating claw 6 and the lower separating claw 7 are installed in the fixing apparatus, a transfer paper P is surely separated from the fixing roller 1 or the pressing roller 2.

Description

Detailed Description of the Invention

The present invention relates to a fixing device for an image forming apparatus such as an electrophotographic copying machine, and more particularly to a fixing device using a heat roller pair.

[0002]

2. Description of the Related Art Such a fixing device has a heated fixing roller and a pressure roller which is brought into pressure contact with the heated fixing roller, and both rollers are rotated to form an unfixed toner image on the pressure contact portion (nip portion). The toner image is fixed on the transfer material by heat and pressure by passing the transfer material carrying the toner.

By the way, in this type of fixing device,
When the unfixed toner on the transfer material melts, an adhesive force acts between the fixing roller and the transfer material, so that the transfer material may wind around the fixing roller, or the release agent may be applied only to the fixing roller. Therefore, the transfer material may wind around the pressure roller. Therefore, a separation member such as a separation claw is directly brought into pressure contact with the fixing roller and the pressure roller to separate the transfer material.

[0004]

However, the conventional fixing device has the following problems because the separating member that contacts the fixing roller and the pressure roller is used.

That is, when the image forming apparatus is left for a long period of time, particularly when a color copying machine or the like which uses a large amount of the releasing agent is left for a long period of time, the releasing agent is dropped onto the separating member along the pressure roller. Therefore, the release agent accumulates on the separation member, and when the device is used after that, the transfer material has its front and rear edges rubbed against the separation member, so that the oil soaks into the transfer material and so-called oil stain occurs. Will end up.

Therefore, the separating member such as the separating claw is not used at all, and the outer diameter of the fixing roller is reduced to increase the curvature of the fixing roller, whereby the repulsive force of the transfer material is greater than the contact force with the fixing roller. A method of separating the transfer material so as to increase the size may be considered.

However, in the method of separating the transfer material by using only the repulsive force of the transfer material as described above, for example, a transfer having a weak repulsion force such as thin paper having a weight per unit area of 60 g / m ² is performed. There is a problem that the separating effect is weak for the material and a winding jam may occur.

The present invention has been made in view of the above problems, and a purpose of the present invention is to make it possible to reliably prevent occurrence of oil stains on the transfer material without impairing the separation performance of the transfer material. To provide.

[0009]

In order to achieve the above object, the invention according to claim 1 has a pair of heat rollers and a separating member that contacts each of the heat rollers, and carries an unfixed toner image. In the fixing device for fixing the toner image on the transfer material by passing the transfer material between the heat rollers, cleaning means for cleaning the separating member is provided.

According to a second aspect of the present invention, in the above first aspect of the invention, the cleaning means has a highly lipophilic cleaning pad that slides along the separating member. .

A third aspect of the present invention is characterized in that, in the first aspect of the present invention, the cleaning means has a nozzle for blowing air to the separating member.

According to a fourth aspect of the present invention, the cleaning means comprises:
It is characterized in that it has a cleaning member attached to an end portion of a guide member arranged in the vicinity of the separating member.

[0013]

According to the present invention, the release agent oil collected in the separating member is cleaning means (cleaning pad, nozzle, cleaning member).
Even if the front and rear ends of the transfer material conveyed thereafter rub against the separating member, oil does not soak into the transfer material, and so-called oil stains on the transfer material are reliably prevented. Get off.

Since the fixing device according to the present invention is provided with the separating member, the transfer material discharged from the heat roller is reliably separated from the heat roller, and the transfer material is securely wound around the heat roller. To prevent.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing the schematic arrangement of a fixing device according to the first embodiment of the present invention. The fixing device comprises a fixing roller 1 and a pressure roller 2 which are pressed against each other and rotate in the direction of the arrow shown in the figure. It is configured to include.

The fixing roller 1 is constructed by incorporating a halogen heater 3 in a cylindrical core metal 1a.
A Teflon layer is coated on the surface of, or a silicone rubber layer is formed, and a Teflon layer is further formed thereon. The pressure roller 2 is formed by forming a silicone rubber layer having a high releasability on the surface of the cylindrical core metal 2a, or by covering the surface of the silicon layer with a Teflon tube.

Then, the fixing roller 1 and the pressure roller 2
The conveyor belt 4 and the entrance guide 5 are disposed on the entrance side (the side on which the transfer material P is carried in and on the right side in FIG. 1), and the exit side (the side on which the transfer material P is discharged). On the left side of FIG. 1, an upper separation claw 6 and a lower separation claw 7 that are in contact with the fixing roller 1 and the pressure roller 2 are provided.

Further, a releasing agent applying device 8 is provided above the fixing roller 1. The releasing agent applying device 8 has a web 11 wound between both rollers 9 and 10 and the web. 1
The fixing roller 1 is configured to include a pressing roller 12 made of a silicon sponge material or the like for pressing the fixing roller 1 against the surface of the fixing roller 1.
The web 11 is made of a non-woven fabric of heat resistant fibers, and is impregnated with silicone oil as a release agent.

By the way, in this embodiment, the lower separating claw 7
The cleaning means 13 is provided in the. This cleaning means 13
As shown in detail in FIG. 2, the cleaning pad 14 comprises a highly lipophilic web or sponge, and the cleaning pad 14
A spring 15 for urging the lower separation claw 7 away from the lower separation claw 7.
And a solenoid 16 that acts on the cleaning pad 14 to press it.

Next, the operation of the fixing device will be described.

From the image forming section (not shown) to the conveyor belt 4
The transfer material P, which carries the unfixed toner image t, is guided by the entrance guide 5 to the nip portion between the fixing roller 1 and the pressure roller 2 by the entrance guide 5, and both transfer rollers 1 and 2 are conveyed. While passing, it is heated and pressed to fix the unfixed toner image t, and then discharged to the outside of the machine.

When the transfer material P is wound around the exit side of the fixing roller 1 or the pressure roller 2, the transfer material P is fixed by the upper separation claw 6 or the lower separation claw 7 to the fixing roller 1 or the pressure roller 2. Separated from. Further, the offset toner remaining on the surface of the fixing roller 1 in contact with the unfixed toner image t is
It is cleaned and removed by the web 11 impregnated with silicone oil.

By the way, when a large amount of release agent (silicon oil) is required in a color copying machine or the like, oil as a release agent is applied to the fixing roller 1 by an oil application unit (not shown). When this is left for a certain period of time without using a copying machine or the like, oil drips along the fixing roller 1 and the pressure roller 2, and the oil is collected on the lower separation claw 7.

Thus, in this embodiment, when a main switch (not shown) is turned on to use a color copying machine or the like, the cleaning means 13 is driven and the lower separation claw 7 is driven.
The oil that collects on the surface is cleaned and removed. That is, when the main switch is turned on, the solenoid 16 is driven and presses the cleaning pad 14, so that the cleaning pad 1
4 slides the lower separation claw 7 against the biasing force of the spring 15.
Then, when the driving of the solenoid 16 is stopped, the cleaning pad 14 returns to the original position by the biasing force of the spring 15.
When these operations are repeated, the cleaning pad 14 reciprocates along the lower separation claw 7 to clean and remove the oil accumulated in the lower separation claw 7.

As described above, when the oil 0 accumulated in the lower separation claw 7 is cleaned and removed by the cleaning means 13, the front and rear ends of the transfer material P conveyed thereafter rub the lower separation claw 7. However, the transfer material P is not soaked with oil, and so-called oil stain on the transfer material P is reliably prevented.

In the above embodiment, the solenoid 16 is used as an actuator for driving the cleaning pad 14 of the cleaning means 13, but a cam or the like may be used instead.

Next, the second and third embodiments of the present invention will be described with reference to FIG.
And it demonstrates based on FIG. Incidentally, FIG. 3 shows the second embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a schematic structure of a fixing device according to an embodiment, and FIG. 4 is a cross-sectional view of a main part of the fixing device according to a third embodiment of the present invention. In these drawings, the same elements as shown in FIG. The same reference numerals are given and the description thereof will be omitted below.

In the second embodiment shown in FIG. 3, the air blowing nozzle 17 is used as a cleaning means for removing the oil accumulated in the lower separation claw 7. When the air blowing nozzle 17 is movable along the trajectory shown by the arrow in the figure and is retracted to the position shown in the normal state, when the color copying machine is used again after being stored for a long period of time. Etc., the orbit is moved toward the lower separating claw 7 as required. Then, air is ejected from the air blowing nozzle 17 toward the lower separation claw 7, and the oil accumulated in the lower separation claw 7 is blown away by the air and cleaned.

Further, in the third embodiment shown in FIG. 4, the cleaning member 19 attached to the end of the guide member 18 is adopted as a cleaning means for removing the oil accumulated in the lower separation claw 7. That is, the guide member 18 is located on the downstream side of the lower separation claw 7 (the downstream side in the transfer material transport direction (not shown), as shown in FIG.
The cleaning member 19 is attached to one end of the guide member 18.

In the steady state, the lower separation claw 7 is in contact with the surface of the pressure roller 2 by a contact spring (not shown) as shown by the solid line in FIG. When it is stored again for a long period of time and then used again, the lower separation claw 7 may move against the urging force of the contact spring as shown by the chain line in FIG. The oil is rotated in the counterclockwise direction and brought into contact with the cleaning member 19, and the oil accumulated in the lower separation claw 7 is cleaned and removed by the cleaning member 19.

Also in the second and third embodiments described above, the oil accumulated in the lower separation claw 7 is removed by cleaning,
As in the first embodiment, oil stains on the transfer material can be reliably prevented.

[0033]

As is apparent from the above description, according to the present invention, there is provided a transfer material having a pair of heat rollers and a separating member which abuts on each of the heat rollers and which carries an unfixed toner image. In the fixing device for fixing the toner image on the transfer material by passing between the heat rollers, a cleaning unit for cleaning the separation member is provided, so that the transfer material separation performance is not impaired. The effect of reliably preventing the generation of oil stains is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a fixing device according to a first exemplary embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing details of cleaning means.

FIG. 3 is a sectional view showing a schematic configuration of a fixing device according to a second embodiment of the invention.

FIG. 4 is a sectional view of a main part of a fixing device according to a third embodiment of the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller (heat roller) 2 Pressurizing roller (heat roller) 6 Upper separation claw (separation member) 7 Lower separation claw (separation member) 13 Cleaning means 14 Cleaning pad 17 Air blowing nozzle (nozzle) 18 Guide member 19 Cleaning Member P Transfer material t Unfixed toner image

Claims (4)

[Claims] 1. A transfer material for transferring the toner image by passing a transfer material carrying an unfixed toner image between the heat rollers, the transfer material having a pair of heat rollers and a separating member abutting on each of the heat rollers. A fixing device for fixing to a fixing device, wherein cleaning means for cleaning the separation member is provided. 2. The fixing device according to claim 1, wherein the cleaning unit has a highly lipophilic cleaning pad that slides along the separating member. 3. The cleaning unit has a nozzle for blowing air to the separating member.
The fixing device described. 4. The fixing device according to claim 1, wherein the cleaning unit has a cleaning member attached to an end portion of a guide member arranged near the separating member.