JPH1010906A - Mold release agent supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold release agent supply device generating no dirt of an image carrier caused by a mold release agent, no wear of a heating roll and a pressing roll, and which is small and easy to maintain. SOLUTION: A mold release agent supply device has a mold release agent supply roll 5 coming in contact with at least one roll of a heating roll and a pressing roll of a fixing device. The mold release agent supply roll 5 is constituted with a cylinder part (a cylindrical core metal 17) for holding a mold release agent 21 in an internal space and a mold release agent coating layer (a mold release agent holding layer 19, a mold release agent control layer 20) formed on the outer circumferential surface of the cylinder part, a film 22 for dividing the internal space of the cylinder part into a mold release agent part and an air part is formed in the internal space, and an air exhausting part (an air hole 23) communicating with the air part and for exhausting air within the air part to the outside of the mold release agent supply roll 5 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes an electrophotographic process such as an electrophotographic copying machine, a facsimile, or a printer for fixing an image by passing an image support having an unfixed toner image between a pair of fixing rollers. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an apparatus, and particularly to a release agent supply device that supplies a release agent to a heating roll or a pressure roll of the fixing device.

[0002]

2. Description of the Related Art Conventionally, in a copying machine or the like utilizing an electrophotographic process, it is necessary to fix an unfixed toner image formed on an image support to a permanent image. , A pressure fixing method, a heat fixing method and the like are known.

However, the above-mentioned solvent fixing method and pressure fixing method have drawbacks such as environmental problems and fixing performance, and at present, they are not widely used.

Accordingly, for fixing unfixed toner, a heat fixing method in which the toner is melted by heating and adhered to an image support is generally widely used.

In this heat fixing method, a fixed pressure is applied between a pair of rolls (a heating roll and a pressure roll), at least one of which is heated, and the image is fixed by passing through an image support having an unfixed toner image. A heat roll method has been conventionally known, and is most widely used because it has advantages such as lower power consumption and less risk of ignition due to paper jam in a fixing section than other heat fixing apparatuses. Fixing method.

In this hot roll system, as shown in FIG. 6, as the heating roll 1, a cylindrical cored bar coated with a heat-resistant elastic material such as silicone rubber or pertetrafluoroethylene is used. A resin coated with a heat-resistant resin such as (PTFE) or perfluoroalkoxy (PFA) is used.

On the other hand, as the pressure roll 2, a heat-resistant elastic body 7 such as silicone rubber or fluorine rubber is provided on the surface of the cylindrical cored bar so as to have a certain contact width when it comes into pressure contact with the heating roll 1. A coated product or a product obtained by coating the heat-resistant elastic body 7 with a heat-resistant resin such as pertetrafluoroethylene (PTFE) or perfluoroalkoxy (PFA) is used.

However, when this heating roll system is used, the unfixed toner on the image support 8 and the heat-resistant elastic body on the surface of the heating roll 1 have poor releasability. A part of the toner is transferred to the heating roll 1, and the toner is re-transferred to the rear end of the image support 8 or to the image support to be passed next, thereby causing a so-called offset phenomenon that stains the image support. Alternatively, there is a problem that the unfixed toner on the image support 8 serves as an adhesive and the image support 8 is wound around the heating roll 1 and ignites.

When the heat-resistant resin is used on the surface of the heating roll 1, the above-mentioned problem of offset and wrapping can be avoided. As a result, there is a problem that the heat-resistant resin layer on the surface of the heating roll 1 is worn, and offset occurs due to partial fixing failure.

Therefore, in order to prevent these problems, generally, silicone oil or the like is applied to the surface of the heating roll 1 as a releasing agent.

In general, a release agent supply device is of a type in which a release agent is applied to the surface of the heating roll 1 using a nonwoven fabric 10 such as felt from a release agent storage container 11 as shown in FIG. Nonwoven paper 1 impregnated with a release agent as shown in FIG.
2, a core metal 13 having a plurality of small holes formed on an outer peripheral surface thereof as shown in FIG. 9, a heat-resistant foam or a nonwoven fabric. And the like, and a porous heat-resistant elastic body and a heat-resistant resin 14 for controlling the supply amount of the release agent. Is applied to the outer peripheral surface of the heating roll 1 and the like to apply a release agent to the surface (for example,
JP-A-60-151680).

However, as shown in FIG. 7, the method of applying a release agent to the surface of the heating roll 1 using a nonwoven fabric 10 such as felt from a release agent storage container 11 requires a large-sized and complicated apparatus. And the release agent is spilled from the release agent storage container 11 to stain the inside of the machine and the image support. Further, as shown in FIG. 8, in a system in which the nonwoven paper 12 is pressed against the heating roll 1 to apply a release agent to the surface, a minute release agent can be supplied. If an attempt is made to increase the amount, the nonwoven paper 12 cannot hold a large amount of release agent, and
There is a problem in that the spills may further contaminate the inside of the machine and the image support. Therefore, recently, as shown in FIG. 9, a method of applying a release agent on the surface by pressing a release agent supply roll 26 filled with the release agent against the outer peripheral surface of the heating roll 1 or the like is often used. Have been.

According to the method using the release agent supply roll, since the release agent is sealed in the cored bar 13, it does not spill outside and prevents the fixing device from becoming large and complicated. It becomes possible. However, when the heating roll 1 is heated, the release agent supply roll 26 is also heated, and the release agent and air existing inside the release agent supply roll 26 thermally expand. Release agent supply roll 2
Since the release agent control layer (porous heat-resistant elastic body and heat-resistant resin 14) for controlling the supply amount of the release agent is formed on the outer peripheral surface of 6, the thermally expanded release agent The air cannot escape to the outside of the release agent supply roll 26 and accumulates in the heat-resistant elastic layer 15, and peels off the heat-resistant elastic layer 15 from the metal core 13 or the heat-resistant elastic layer 15 of the release agent control layer. From the mold, making it impossible to control the supply amount of the release agent, causing a problem in that the release of the release agent and abrasion of the heating roll due to the shortage of the release agent are caused, and in a high-temperature condition, The use of the release agent supply roll 26 is limited.

[0014]

SUMMARY OF THE INVENTION The present invention eliminates and improves the above-mentioned drawbacks of the prior art. In a fixing device comprising a heating roll and a pressure roll, at least one of the above rolls is used. By providing a release agent supply device capable of stably supplying a fixed amount of release agent over a long period of time on the surface of the image bearing member, contamination of the image carrier by the release agent and the heating roll and pressure roll It is an object of the present invention to provide a release agent supply device which is small in size and easy to perform maintenance and inspection without causing abrasion.

[0015]

That is, the present invention relates to a release agent supply device having a release agent supply roll provided in contact with at least one of a heating roll and a pressure roll of a fixing device. The release agent supply roll comprises a cylindrical portion for holding a release agent in an internal space and a release agent coating layer formed on an outer peripheral surface of the cylindrical portion. The internal space was provided with a film for separating this space into a release agent portion and an air portion, and an air discharge portion was provided following the air portion to discharge air in the air portion to the outside of the release agent supply roll. It is characterized by the following.

This makes it possible to prevent the release agent supply layer of the release agent supply device from being damaged, and to stably prevent the image carrier from being stained by the release agent and offset for a long period of time.

[0017]

FIG. 1 is a schematic sectional view of a fixing device to which a releasing agent supply device of the present invention is applied. FIG.
The members corresponding to those shown in FIG.

The fixing device used in this embodiment is as follows.
As shown in FIG. 1, a pressure roll 2 is provided at a position in contact with a heating roll 1, and the heating roll 1 is heated by a heating lamp 3. The heated temperature of the heating roll 1 is detected by a temperature detecting sensor 4 and C.I. P. U. It is determined whether heating is to be performed again or the heating is to be stopped.
Is used to maintain the temperature of the heating roll 1 at a predetermined value. In addition to the case where the heating source is provided on the heating roll 1 as shown in FIG. 1, a heating source provided on the pressing roll 2 or a heating source provided on both the heating roll 1 and the pressing roll 2 can be considered. On the surface of the heating roll 1, there are provided a release agent supply roll 5 for applying the release agent to the heating roll 1, and a peeling claw 6 for peeling the fixing paper from the heating roll 1. The image support 8 having the unfixed toner image formed thereon passes through the paper guide 9, passes through a nip formed by the heating roll 1 and the pressure roll 2, and fixes the toner image on the image support 8. .

A release agent supply roll 5 provided in pressure contact with the surface of the heating roll 1 is supported so as to be able to be driven by the rotation of the heating roll 1, and has a cylindrical shape in which a release agent is sealed. Shape. The release agent oozing out from the peripheral wall of the release agent supply roll 5 is applied to the heating roll 1 so as to prevent the above-described offset phenomenon and the like.

As shown in FIGS. 2 and 3, the release agent supply roll 5 is made of a metal such as aluminum, iron, copper, or stainless steel and has a small hole 18 having a diameter of 1 to 3 mm.
And a release agent holding layer 19 formed of a heat-resistant felt, silicone sponge, or the like that covers the core metal with a thickness of 1 to 3 mm. A release agent control layer 20 formed of a polytetrafluoroethylene porous film having a thickness of several tens of micrometers, a silicone-based varnish of a heat-resistant resin, and the like;
7, a circular rigid body 16 (including both a disk part and a cylindrical part) for shielding the openings at both ends, and provided so as to be sandwiched between the circular rigid body 16 and the cylindrical core 17; It is composed of a release agent 21 and a film 22 for separating air (see FIG. 4). A projection (cylindrical portion) serving as a rotation axis of the release agent supply roll 5 is provided in the vicinity of an axially outer axis of the rigid body 16, and an air hole communicating with the inside of the film 22 is provided on the axis of the projection. 23 are provided. Release agent holding layer 19
In addition to those having a single-layer structure, those having a multi-layer structure in which nonwoven paper or the like is added can also be considered.

Approximately 100 cc of silicone oil having a viscosity of 100 to 1000 CSt is sealed as a mold release agent 21 between the cylindrical core 17 and the membrane 22. , And is impregnated and held in the release agent holding layer 19, and the structure of the release agent control layer 20 prevents unlimited leaching from the release agent holding layer 19. .

As shown in FIG. 5, the release agent supply roll 5 has a surface of the heating roll 1 through a bearing 24 and a spring 25 through a bearing 25 for 1-2 k sufficient to be driven by the heating roll 1.
gf with a load of 1-3 g between the heating roll 1
A nip width of m is formed. The release agent holding layer 19 is compressed by this nip area, and the silicone oil impregnated therein penetrates and leaches through the thin film layer of the release agent control layer 20 to form a certain amount of water on the surface of the heating roll 1. It has a structure in which silicone oil is applied. Since the silicone oil does not leach out of the release agent holding layer 19 indefinitely due to the action of the thin film layer of the release agent control layer 20, the release agent 21 has good holding properties and the consumed silicone oil is A constant amount of silicone oil supplied from the above is always impregnated and held inside the release agent holding layer 19, so that the required amount of silicone oil can be stably supplied to the surface of the heating roll 1 for a long period of time. It has a configuration.

Since the release agent supply roll 5 is in pressure contact with the surface of the heating roll 1, the temperature of the release agent supply roll 5 is stably maintained at a temperature slightly lower than the temperature of the heating roll 1. For example, when the temperature of the heating roll 1 is 150 ° C., the temperature of the release agent supply roll 5 is maintained at about 130 ° C. As the temperature of the release agent supply roll 5 rises, the air inside the film 22 existing inside the cylindrical core 17 and the release agent 21 outside the film 22 begin to expand, and the cylindrical core 17 The internal pressure will increase. Due to this pressure increase, the air in the membrane 22 is discharged to the outside through the air holes 23 provided in the rigid body 16, and the cylindrical core 1
7 can be reduced in pressure.

As shown in FIG. 5, the film 22 is made of a heat-resistant resin (for example, Teflon, polyimide or the like) and has a thickness of several μm to several tens μm and is tapered at one end to seal it. is there.

With the above structure, the pressure inside the cylindrical core 17 can be kept constant without spilling the release agent 21 held inside the cylindrical core 17 to the outside. In addition, it is possible to prevent the toner offset phenomenon due to the shortage of the supply of the release agent due to the decrease of the release agent 23 and the phenomenon of the release agent dripping onto the image support due to the release agent dripping for a long time.

In the above embodiment, the release agent supply roll 5 is attached to the heating roll 1, but the release agent supply roll 5 may be attached to the pressure roll 2. In some cases, the release agent supply roll 5 may be attached to both the heating roll 1 and the pressure roll 2.

[0027]

According to the present invention, there is provided a release agent supply device provided with a film for holding a release agent therein and separating air from the release agent, and comprising at least one of a heating roll and a pressure roll of a fixing device. It is provided in contact with the surface of one of the rolls, and by the action of the film, the pressure inside the release agent supply device can be kept constant, and the release provided on the surface of the release agent supply device It is possible to prevent the agent control layer from being damaged.

Accordingly, the release agent supply device of the present invention can hold a large amount of the release agent since the release agent can be sealed in the entire inside of the cylindrical core metal as compared with the conventional one. It is possible to reduce or eliminate the need for replacement of the release agent supply device, thereby significantly reducing maintenance and inspection work, and applying a required amount of release agent to the surface of the heating roll or the like. Can be prevented over a long period of time, and contamination of the image support by the release agent can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a fixing device to which a release agent supply device of the present invention is applied.

FIG. 2 is a schematic sectional view of a release agent supply roll.

FIG. 3 is a partially cutaway perspective view of a release agent supply roll.

FIG. 4 is a perspective view showing a film inside the release agent supply roll alone.

FIG. 5 is a partial schematic perspective view illustrating a pressing mechanism of a release agent supply roll.

FIG. 6 is a schematic sectional view of a fixing device to which a conventional release agent supply device is applied.

FIG. 7 is a schematic cross-sectional view showing a conventional release agent supply device for applying a release agent to the surface of a heating roll using a nonwoven fabric.

FIG. 8 is a schematic cross-sectional view showing a conventional release agent supply device in which a nonwoven paper impregnated with a release agent is pressed against a heating roll to apply a release agent to a surface thereof.

FIG. 9 is a schematic cross-sectional view showing a conventional release agent supply device that applies a release agent to a surface by pressing a release agent supply roll against a heating roll.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heating roll, 2 ... Pressure roll, 3 ... Heating lamp, 4
... temperature detection sensor, 5: release releasability roll, 6 ... paper peeling claw, 7 ... elastic body, 8 ... image support, 9 ... paper guide, 1
0: non-woven fabric, 11: container for release agent storage, 12: non-woven paper,
13: core metal, 14: heat-resistant resin, 15: heat-resistant elastic layer,
16: circular rigid body, 17: cylindrical core, 18: small hole,
19: release agent holding layer, 20: release agent control layer, 21: release agent, 22

Claims (3)

[Claims] 1. A release agent supply device comprising a release agent supply roll provided in contact with at least one of a heating roll and a pressure roll of a fixing device, wherein the release agent supply roll Comprises a cylindrical portion that holds the release agent in the internal space, and a release agent coating layer formed on the outer peripheral surface of the cylindrical portion. This space is released from the internal space of the cylindrical portion. A release agent for supplying a release agent, wherein a film for separating the release agent and the air portion is provided, and an air discharge portion connected to the air portion and discharging air in the air portion to the outside of the release agent supply roll is provided. apparatus. 2. The release agent supply device according to claim 1, wherein a layer for controlling the release agent supply amount is provided on the surface of the release agent supply roll. 3. The release agent supply device according to claim 1, wherein the air discharge unit is provided at an end of the release agent supply roll.