JPH01303471A - Releasing agent coating device - Google Patents

Abstract

PURPOSE:To prevent an oil spotting phenomenon from occurring by bringing a porous member which is impregnated with a releasing agent into contact with a body to be coated and arranging a heat-resisting member which prevents an excessive releasing agent from flowing out on the upstream side of the porous member in the moving direction of the body to be coated. CONSTITUTION:The porous member 13 of 'Boaflon(R)', etc., impregnated with the releasing agent is pressed against the outer peripheral surface of an upper roller 1. The heat-resisting sheet 17 is fitted to the side plate of a holder 14 on the upstream side of the upper roller 1 in its rotating direction and contacts the upper roller 1 under such pressure that the upper roller 1 is not flawed; even if the sheet is left in a stand-by state, the releasing agent which oozes from the porous member 13 and flows out to the side of a separating claw is cut off by the heat-resisting sheet 17. Consequently, the releasing agent is prevented from sticking on a member to be transferred and the oil spotting phenomenon is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a release agent coating device for applying a release agent to an object to be coated.

(Prior Art) This type of release agent application device is used, for example, in a fixing device of an electrophotographic copying device or an electrostatic recording device to prevent toner offset.

FIG. 7 shows the general structure of a fuser with a heat roller system, and the fuser includes an upper roller 1 and a lower roller 2. At the same time, a thermistor 4 is placed facing the circumferential surface of the transfer material (plain paper, etc.) that has passed through the input logite 5.
It passes between the upper roller 1 and the lower roller 2.

As is well known, a toner image formed on a transfer material (plain paper, etc.) by an electrophotographic method such as the so-called Carlson process passes through a pair of rollers without being held under pressure during the final tightening process. . In this step, the thermoplastic toner is melted and pressed onto the transfer material, so that the toner image is fixed on the transfer material, and is then discharged.

However, in such a fixing device, even if sufficient toner melting is achieved, a small amount of the toner image is transferred onto the roller due to thermal or electrostatic action. This is generally referred to as an offset phenomenon, and causes problems such as offset toner being carried by the roller, staining the thermistor surface, or being transferred to the next copy image as an unnecessary image. Therefore, in general, a release agent such as silicone oil is applied to the surface of the roller in order to reduce the offset of the toner onto the roller. As for this coating method, many methods have been proposed and put into practice.

For example, there are methods using heat-resistant nonwoven fabric, methods in which the release agent is applied in appropriate amounts using a coating roller (roller coating), and methods in which the release agent is applied through a heat-resistant (fluororesin-based) porous membrane.

However, all of these methods require oversized equipment, and in recent years there has been a demand for smaller, easier-to-maintain coating equipment. Some use resin. This is done by stretching heat-resistant resin such as fluororesin to make it into fibers, impregnating the voids between the fibers with a mold release agent such as silicone oil, and holding this in a heat-resistant resin holder. It is brought into contact with a fixing roller or a pressure roller as an application body with an appropriate pressure. For example, in the seventh [A], the porous member 6A as described above is in contact with the upper roller I.

Since the mold release agent impregnated into the porous resin usually has a high viscosity of 100OC or more at room temperature, it must be kept in the pores of the porous resin or removed from the fixing roller, etc. When heated, the mold release agent is also heated through the porous resin and its viscosity decreases to approximately 1710).
This mold release agent migrates to the roller surface by capillary action and is exposed to the roller.

(Problem to be solved by the invention) Therefore, the above roller is supposed to be constantly coated with a fixed amount of a mold release agent impregnated in a porous resin, or is it actually the case that the mold release agent or the initial coating is applied to the roller? There is a tendency to over-discharge the release agent, and after that, as the release agent is discharged using a constant R1 device (as the number of sheets of transferred material used increases), it will gradually decrease and reach a stable value. Ta.

For this reason, the fuser shown in FIG. 7 is set to the initial standby state.
Leave it as it is and after about 20 minutes, the porous member 6A
Excess release agent oozes out from the mold, flows over the fixing roller 1, adheres to the separation claw 6, and stays there. Furthermore, the excess release agent flows over the fixing roller l, reaches the pressure roller 2, and also adheres to the separation guide 7 on the pressure roller 2. Then, the release agent that adheres to the separation claw 6 and remains there adheres to the leading or trailing edge of the transferred material when the transferred material passes through the fixing device, resulting in a phenomenon called oil staining. There was a problem.

The present invention has been made in view of the above problems, and its purpose is to prevent the occurrence of so-called oil stain development by preventing the release agent excessively exuded from the porous member from adhering to the transfer material. To provide a release agent coating device 2 which can effectively prevent mold release agent.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a mold release agent in which a porous member impregnated with a mold release agent is brought into contact with an object to be coated that moves relative to the porous member. The coating apparatus is characterized in that a heat-resistant member for preventing excess mold release agent from flowing out is disposed on the 1-stream side of the porous member with respect to the interlocking direction of the object to be coated.

(Function) Therefore, the excessive leakage of the release agent from the porous member to the upstream side in the pressure direction of the object to be coated is effectively prevented by the #thermal member disposed on the hIi side of the porous member. This prevents the release agent from adhering to the transfer material, thereby preventing so-called oil stain development.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

The first IN is a side sectional view of the mold release agent coating device according to the present invention, and in the same figure, l is an upper roller rotating in the direction of arrow P in the figure, and on the outer circumferential surface of the upper roller l.

A porous member 13, such as Boa-Fron, impregnated with a mold release agent such as silicone oil, is pressure-welded. This porous member 13 is held by a holder 14, and the holder 14 is fitted and held by a guide member 15 fixed to the main body of the fixing device. The holder 14 is urged toward the upper roller l by the splinter 16, and as a result, the holder 1
The porous member 13 held at 4 is pressed against the outer circumferential surface of the upper roller 1 with a constant pressure.

By the way, the holter 1 on the upstream side in the rotational direction of the upper roller l
A heat-resistant sheet 17 made of Kabutone, Teflon, rubber, etc. is attached to the side plate of 4, and this heat-resistant sheet 17 contacts the L roller l with a pressure large enough not to damage the upper roller 1. The width of the fixing device is set wider than the width of the transfer material passing through the fixing device.

According to this embodiment, even if the release agent is left in the standby state in the initial stage, the release agent that has excessively exuded from the porous member 13 and flowed out to the separation claw side (not shown) is removed by the heat-resistant sheet. ) 17, this prevents it from adhering to the separating claw, and also prevents the GI agent from adhering to the transfer material, thereby preventing so-called oil stain development.

In addition, even if the dammed release agent moves to the flow side when the upper roller l rotates or flows out from the edge of the heat-resistant sheet 17, as described above,
Since the width of 7 is wider than the width of the transferred material to be inserted, the release agent will not adhere to the edge of the transferred material! , 1 [The agent passes through the upper rollers L and F rollers and reaches the bottom plate of the fixing device.

In this embodiment, the heat-resistant sheet 17 is
The heat-resistant sheet 17 may be bonded to the side plate of the porous member 14 or sandwiched between the porous member 13 and the side plate of the holter 14 as shown in FIG. The seat 17 can be easily replaced.

In addition, in the above embodiment, the heat-resistant sheet 17 is placed on the upper roller l.
The upper roller l and the heat-resistant sheet 17 are in contact with each other.
If the distance between the heat-resistant sheet 17 and the mold release agent blocked in front of the upper roller 17 is kept within a range that does not flow out to the upstream side in the rotational direction of the upper roller 1 due to surface tension, the heat-resistant sheet 17 can be It is not necessary to contact l.

Next, modified embodiments of the present invention are shown in FIGS. 3, 4, and 5UA.
and Fig. 6 respectively. In these figures, the same elements as shown in FIG. 1 are given the same reference numerals.

In the embodiment shown in FIG. 3, a heat-resistant absorbing member 18 such as felt or sponge is attached to the side plate of the holder 14 on the upstream side in the direction of rotation of the upper roller l. The width of the heat-resistant absorbing member 18 is set wider than the width of the copying material, similar to the width of the heat-resistant sheet in the embodiment described above. Unlike a sheet, the heat-resistant absorbing member 18 absorbs the excess release agent that has flowed out to the separating claw side, so it does not flow out onto the bottom plate of the fixing device through the upper roller l, and instead is absorbed into the fixing device. It also has the effect of preventing oil stains.

In the embodiment shown in FIG. 4, a heat-resistant absorbent member 18 such as felt or sponge is attached to the support member 19, and the heat-resistant absorbent member 18 is pressed against the upper roller l with a constant pressure. The heat-resistant absorbing member 18 functions not only as an absorbing member for the release agent, but also as an auxiliary cleaning member for cleaning the toner offset to the upper roller. Also, if the configuration is as in this embodiment,
If the heat-resistant absorbent member 18 is dirty due to toner adhesion even though the release agent remains in the porous member 13, it is only necessary to replace the heat-resistant absorbent member 18. It's convenient.

Furthermore, in FIGS. 5 and 6, a roller 21 made of a heat-resistant material such as felt or sponge is attached to a splinter 20.
The roller 21 is shown in an embodiment in which it is brought into pressure contact with the upper roller 1, or the roller 21 is detachably inserted into the halter 14.

Therefore, in this embodiment, the roller 21 is the upper roller l.
The mold release agent that has flowed out in excess is absorbed by the roller 21, and the mold release agent absorbed by the roller 21 is again supplied to the upper roller 1. In this case, since the entire circumference of the roller 21 is used, the area of contact with the 10-l can be increased, which is advantageous against clogging of the roller 21 due to adhesion of offset toner.

In the above embodiments, the present invention has been specifically applied to a fixing device of an image forming apparatus, but the present invention can be applied to any other apparatus.

(Effects of the Invention) As is clear from the above description, according to the present invention, a release agent application device is provided that is brought into contact with a member to be coated that moves relative to a porous member impregnated with a release agent. In this case, a heat-resistant member to prevent excess mold release agent from flowing out is disposed upstream of the porous member with respect to the moving direction of the object to be coated, so that excessive mold release agent oozes out from the porous member. The outflow of the material to be coated to the upstream side in the direction of M movement is effectively prevented by the heat-resistant member disposed upstream of the porous member, and the adhesion of the thin agent to the material to be transferred is prevented, resulting in so-called oil stains. The effect of preventing development from occurring can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of a mold release agent coating device according to the present invention, and FIGS.
A side sectional view of the device, FIG. 6 is a view in the direction of the arrow in FIG. 5, and FIG.
The figure shows a side cross section of a fixing device equipped with a conventional release agent coating device [A
It is. ■... L roller (71 objects to be coated), 13... Porous member, 17... Heat resistant sheet (heat resistant member), 18...
・Heat-resistant absorption member (heat-resistant member), 21...roller (
heat-resistant components). Patent applicant Ryo Yamashita, agent for Canon Co., Ltd., patent attorney - Figure 1, Figure 3, Figure 4

Claims (1)

[Claims] In a release agent application device in which a porous member impregnated with a release agent is brought into contact with an object to be coated that moves relative to the porous member, the upstream side of the porous member with respect to the moving direction of the object to be coated is provided. A mold release agent application device characterized in that a heat-resistant member is disposed on the side to prevent excess mold release agent from flowing out.