JP2002278345A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of uniformly applying oil (mold release agent) to a fixing roller or a pressurizing roller even when the arrangement state of a pipe member is inclined. SOLUTION: A plurality of oil outflow holes 45, 45,... are formed on the upper part of the oil supplying pipe member 44 extended in parallel with the fixing roller 1 in an oil supplying mechanism 4 for applying oil (O) to the outer periphery of the fixing roller 1 of the fixing device. A guide sheet 5 is fitted to the side face of the member 44. A plurality of inverted triangular guide pieces 51, 51,... are formed on the sheet 5 along the member 44. Oil (O) flowing out from respective holes 45, 45,... is allowed to flow down along the guide pieces 51, 51,... dropped from the lower ends of the pieces 51, 51,... and applied to the fixing roller 1 by an oil application roller 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device which is mounted on an electrophotographic image forming apparatus and has a roller for fixing a developer (toner) to the surface of a sheet material (recording paper). In particular, the present invention relates to an improvement in an operation of applying a release agent (oil) to a roller surface.

[0002]

2. Description of the Related Art Conventionally, a fixing device mounted on an electrophotographic image forming apparatus such as a copying machine or a printer has a roller for fixing a toner image while nipping and conveying a recording sheet. It has been practiced to apply a release agent such as silicon oil to the surface. The application of the release agent prevents so-called offset, in which a part of the toner on the recording paper adheres to the roller, and also prevents winding of the recording paper around the roller, thereby stably forming a high-quality image. To be able to do it.

As a configuration for applying oil to a roller, for example, as disclosed in Japanese Patent Application Laid-Open No. 8-137317, there is a configuration using a pipe member having a plurality of oil outflow holes. Hereinafter, this configuration will be specifically described.

[0006] As shown in FIG. 6, the fixing device includes a fixing roller a and a pressure roller b.
An oil tank c is arranged below the oil tank c. A piezo-type or electromagnetic pump d is placed above the oil tank c.
And a pipe member e is connected to the discharge side of the pump d. The pipe member e has rollers a,
It is located above the position where b is disposed, and extends parallel to the roller axis. Further, at the upper end of the pipe member e, oil outflow holes f,
f,... are formed. By driving the pump d, the oil pumped from the oil tank c is supplied to the pipe member e, and the oil flows out from the oil outlet holes f, f,. Then, the oil flows down along the outer peripheral surface of the pipe member e, and the pipe member e
From the drop. As shown in FIG. 7 (plan view), an oil receiving plate h having a felt g on its upper surface is disposed at the oil dropping position. Surfaces are touching. Furthermore,
The outer peripheral surface of the oil application roller i is also in contact with the outer peripheral surface of the fixing roller a. For this reason, the oil dropped from the pipe member e is applied to the surface of the fixing roller a via the felt g on the oil receiving plate h and the oil applying roller i.

[0005]

When the installation state of the image forming apparatus main body is inclined, the arrangement state of the pipe member e is also inclined. Further, even when the installation state of the image forming apparatus main body is horizontal, the arrangement state of the pipe member e may be inclined due to an assembly error of the pipe member e. Since the oil flowing out of the oil outlet holes f, f,... Flows along the outer peripheral surface of the pipe member e and drops from the lower end thereof, when the arrangement state of the pipe member e is inclined as described above, the oil Flows downward along the outer peripheral surface of the pipe member e.

FIG. 8A shows a state in which the oil o is dropped when the arrangement state of the pipe member e is horizontal. As described above, when the arrangement state of the pipe member e is horizontal, the oil o is dripped evenly at various places, and the oil o can be applied uniformly over the entire surface of the fixing roller a. . FIG. 8B shows a state where the oil o is dropped when the arrangement state of the pipe member e is inclined. As described above, when the arrangement state of the pipe member e is inclined, the oil o flows toward the lower side (to the left in the figure) along the outer peripheral surface of the pipe member e. The drop position of the oil o is different from the predetermined drop position, resulting in a non-uniform oil application state on the fixing roller a. Particularly, in a portion where the oil application amount on the fixing roller a is insufficient, There has been a problem that the offset occurs and the recording paper is wound. Further, since the oil supply to a part becomes excessive, there is a possibility that oil leaks from the fixing device.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to provide a fixing roller or a pressure roller with oil (even when the arrangement of a pipe member is inclined). It is an object of the present invention to provide a fixing device capable of uniformly applying a release agent).

[0008]

Means for Solving the Problems-Summary of the Invention-In order to achieve the above object, the present invention provides a release agent supply means for supplying a liquid release agent for flowing down onto a roller surface. A guide piece formed in a shape that regulates the flowing direction of the release agent is provided. Thus, the release agent can be applied to necessary portions of the roller surface regardless of the inclination of the cylindrical body (pipe member) for supplying the release agent.

-Solution Means- Specifically, a pair of rollers for fixing the developer to the surface of the sheet material while nipping and conveying the sheet material, and a liquid release agent is supplied to at least one surface of these rollers. It is assumed that the fixing device includes a release agent supply unit. Then, the release agent supply means is provided with a cylindrical body and a guide means. The cylindrical body extends substantially parallel to the roller to which the release agent is supplied, and has a hole for releasing the release agent. The guide means causes the release agent flowing out of the hole of the cylindrical body to flow down. Further, the guide means is provided with a guide piece formed in such a shape that the width dimension gradually decreases toward the lower side so as to regulate the flow direction of the release agent.

According to this specific matter, when the release agent is applied to the roller surface, the liquid release agent flows out of the hole of the cylindrical body, and the release agent flows down the surface of the cylindrical body. The released release agent flows from the cylindrical body along the guide piece. At this time, since the guide piece is formed in a shape in which the width dimension gradually decreases toward the lower side, the flow-down direction of the release agent is directed to the portion of the lower end of the guide piece having the shortest width dimension. Become. For example, when the guide piece is formed in an inverted triangle, the release agent flows down toward the vertex at the lower end. Therefore, it is possible to regulate the flow-down direction of the release agent according to the shape of the guide piece, and even if the tubular body is inclined, the oil is directed toward the lower end of the guide piece. Is regulated, so that a release agent can be applied to a required portion of the roller surface.

The following are specific examples of the structure of the guide piece. That is, a plurality of guide pieces are arranged along the roller extension direction. According to this, the flow-down direction of the release agent is a direction regulated by each guide piece. That is, the flow-down point of the release agent can be set at the lower end of each guide piece, and the release agent can be evenly supplied to a plurality of locations, and supply of the release agent to almost the entire surface of the roller. Can be performed reliably.

Further, when the guide piece is formed of a material having permeability, it is possible to avoid a situation in which the release agent flowing into the guide piece drops from a portion other than the lower end of the guide piece. In addition, it is possible to accurately regulate the flowing direction of the release agent.

Further, the upper end of the guide piece is brought into contact with the side surface of the cylindrical body so that the release agent flowing out of the hole of the cylindrical body flows down. If formed on the side where the guide piece is slightly in contact with the upper end,
Most of the release agent flowing out of the hole of the cylindrical body can flow in the direction toward the guide piece. That is, it is possible to avoid a situation in which the release agent that has flowed out of the hole of the cylindrical body drops without flowing through the guide piece.

The following is a specific example of the configuration in which the positional relationship between the hole of the cylindrical body and the guide piece is specifically specified. That is, holes of the cylindrical body are formed at a plurality of locations along the roller extension direction, and each guide piece is arranged corresponding to the position of the hole of the cylindrical body. Similarly, holes in the cylindrical body are formed at a plurality of locations along the roller extension direction,
A plurality of guide pieces are arranged corresponding to each of the holes of the cylindrical body. According to these configurations, the oil flowing out from each hole flows into the guide piece corresponding to the hole, so that the flow rate of the oil in each guide piece can be equalized. Therefore, it is possible to reliably apply the release agent to substantially the entire surface of the roller. In particular, according to the latter configuration, it is possible to increase the flow-down point of the oil from the guide means without increasing the number of holes in the cylindrical body,
The release agent can be applied to almost the entire surface of the roller more reliably.

[0015]

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

FIG. 1 is a perspective view showing a part of the fixing device according to this embodiment. FIG. 2 is a side view showing a part of the fixing device in cross section. As shown in these drawings, the present fixing device includes a fixing roller 1 and a pressure roller 2 which are arranged vertically and are pressed against each other. These fixing rollers 1
Each of the pressure rollers 2 has a rubber layer made of silicon rubber on an aluminum pipe, and has heaters 11 and 21 composed of halogen lamps inside thereof. A drive source (not shown) (not shown) is connected to the fixing roller 1, and each of the rollers 1 and 2 rotates in a direction indicated by an arrow in the figure as the sheet is driven by the drive source. While holding the recording paper P, the toner image on the recording paper P is heated and fixed.

Around the fixing roller 1, an upper peeling claw 12,
Upper cleaning roller 13, fixing roller temperature detector 1
4. An oil application roller 3 is provided. On the other hand, around the pressure roller 2, a lower peeling claw 22, a lower cleaning roller 23, and a pressure roller temperature detector 24 are provided.

The peeling claws 12 and 22 separate the recording paper P to be wound around the rollers 1 and 2 from the surfaces of the rollers 1 and 2. Each cleaning roller 13, 23
Is a roller whose surface is made of felt, which collects the offset toner adhered to the surfaces of the fixing rollers 1 and the pressure roller 2 by slidingly contacting the surfaces of the rollers 1 and 2.

Each of the roller temperature detectors 14 and 24 is composed of a thermistor, and detects the surface temperature of the rollers 1 and 2 with which the rollers contact. Each roller temperature detector 14, 24
Is sent to a fixing control unit (not shown). The fixing control section includes the roller temperature detectors 14 and 24
The operation of the power supply unit is controlled based on the detection result of
Is turned on / off to adjust the temperature of the rollers 1 and 2.

The oil application roller 3 is a roller having a surface made of rubber, and receives oil (liquid release agent) from an oil supply mechanism 4 as a release agent supply means described later, and applies the oil to the fixing roller 1. It is applied to the surface.

Next, the oil supply mechanism 4 for supplying oil to the surface of the fixing roller 1 will be described.

An oil tank 41 is provided at the lower end of the fixing device.
Is installed. Oil O is stored in the oil tank 41. As the oil O, dimethyl silicone oil having a viscosity of 100 CS to 300 CS can be used, but a modified silicone oil (for example, a reactive silicone oil, a non-reactive silicone oil, or the like) may be used. However, a material having a high viscosity is not preferable because it makes it difficult to draw up the pump.

A pump 42 is connected to an upper portion of the oil tank 41, and a pipe member 44 is connected to a discharge side (upper side in the figure) of the pump 42 via a tube 43. The pipe member 44 is installed diagonally above the fixing roller 1 and parallel to the fixing roller 1. The pipe member 44 has oil outflow holes 45 formed at a plurality of locations along the longitudinal direction. For this reason, the oil O pumped from the oil tank 41 with the driving of the pump 42
3 and is supplied to the pipe member 44, and the pipe member 4
4 are discharged from the respective oil outlet holes 45, 45,. One end of the pipe member 44 (the end opposite to the side connected to the pump 42) is closed by caulking or the like, and when oil is supplied to the pipe member 44, each oil flows out. The oil is prevented from flowing out of places other than the holes 45, 45,.
The length of the pipe member 44 is substantially the same as the length of the fixing roller 1 and the pressure roller 2.
The area where is formed corresponds to the longitudinal dimension of these rollers 1 and 2.

The inside diameter of the pipe member 44 is
For example, when the oil outflow per unit time of the pump 42 is about 3 to 30 g / min, the inner diameter of the pipe member 44 is appropriately 5 to 10 mm. The material of the pipe member 44 is not particularly limited, but a metal pipe made of aluminum, iron, or brass can be used. Further, the oil outlet hole 45 is
The oil outlet hole 45 preferably has a diameter of about 1.5 mm, and can be formed by, for example, press working or laser processing. The number of the oil outlet holes 45 is arbitrary, but it is necessary that the number of the oil outlet holes 45 is such that the oil O can be uniformly applied to substantially the entire outer peripheral surface of the fixing roller 1 (for example, 7 to 9). Also, since the oil O is supplied from one end of the pipe member 44, the diameter of the oil outflow holes 45, 45,. Gradually increase,
The amount of oil discharged from each of the oil outlet holes 45 may be made uniform. Note that the above numerical values are not limited to these.

Below the pipe member 44, an inclined oil receiving plate 46 is provided, and a felt material 47 is provided on the oil receiving plate 46.
Is attached. That is, the oil O which has flowed out from the oil outflow holes 45, 45,.
Is received by the oil receiving plate 46 and flows down toward the felt material 47 so that the felt material 47 is impregnated with the oil O.

Further, the outer peripheral surface of the oil application roller 3 is in contact with a felt material 47.
Is applied to the outer peripheral surface of the fixing roller 1 through the oil application roller 3.

A rubber coating blade 48 is in contact with the outer peripheral surface of the oil applying roller 3, and the oil O on the outer peripheral surface of the oil applying roller 3 is made uniform in a thin film by the applying blade 48. It has become.

Further, below the oil receiving plate 46, an oil pan 49 is provided. The oil pan 49 is for collecting the oil O when surplus oil not adhered to the oil application roller 3 drops from the oil receiving plate 46. The oil pan 49 is connected to the oil tank 41 by an oil collecting tube 49a, and returns the collected surplus oil into the oil tank 41. That is, while circulating the oil O between the oil tank 41 and the pipe member 44, only a necessary amount of oil can be applied to the outer peripheral surface of the fixing roller 1 via the oil application roller 3. I have.

Further, inside the oil tank 41, an oil remaining amount detection sensor 41a for detecting the remaining amount of oil in the oil tank 41 is provided. When the remaining oil level sensor 41a detects that the remaining oil level in the oil tank 41 has become equal to or less than a predetermined level, a warning is displayed on the display panel of the image forming apparatus, and the user is notified of the oil level. It is designed to encourage replenishment. Further, when the oil is insufficient, the image forming apparatus may be temporarily disabled.

Next, the characteristic features of the present embodiment in the pipe member 44 and its peripheral portion will be described. As shown in FIG. 3, a guide sheet 5 as a guide unit is attached to a side surface of the pipe member 44. The guide sheet 5 is made of felt having a thickness of, for example, about 1 mm, and has a plurality of guide pieces 51, 51,... Formed in an inverted triangular shape such that the width dimension gradually decreases toward the lower side.
, And a connecting portion 52 that horizontally connects upper end edges of the guide pieces 51, 51,...
The guide pieces 51, 51,... Are arranged corresponding to the positions of the oil outflow holes 45, 45,. In other words, the guide pieces 45 and 4 are arranged such that the center line of the inverted triangular guide piece (the straight line L indicated by a dashed line in FIG. 3) and the position of the oil outlet hole 45 overlap in the vertical direction.
5,... Are formed.

As shown in FIG. 4 (a cross-sectional view taken along line IV-IV in FIG. 3), the oil outlet hole 45 of the pipe member 44 is larger than the upper end of the pipe member 44 in the guide sheet 5.
Is formed at the position where the is attached (right side in FIG. 4). The position of the oil outlet hole 45 is determined by the pipe member 4.
An angle α formed by a straight line L1 connecting the axis of No. 4 to the upper end and a straight line L2 connecting the axis of the pipe member 44 and the center of the oil outlet hole 45 is, for example, 5 to 30 ° (preferably 5 to 10 °). It is set to be. Therefore, the oil outflow hole 4
Most of the oil O flowing out of the pipe 5 flows on the right side surface of the pipe member 44 in FIG. 4 (see the arrow in the figure), so that the oil O is smoothly absorbed by the guide sheet 5.

Further, as described above, each of the guide pieces 51, 5
Are oil outlet holes 45, 4 of the pipe member 44.
Are arranged corresponding to the positions 5, 5, so that the oil O flowing out from the individual oil outflow holes 45, 45, flows into the guide pieces 51 located therebelow. Therefore, the flow rate of the oil O in each of the guide pieces 51, 51,... Can be made substantially equal to each other. Since the guide pieces 51, 51,... Are formed in an inverted triangular shape, the oil O soaked into the guide piece 51 flows down the guide piece 51, and the flowing direction is the lower end of the guide piece 51 (an inverted triangle) (Lower vertex). The oil O is supplied to each of the guide pieces 51, 51,.
After being dropped from the lower ends of the fixing rollers 1 through the oil receiving roller 46 and penetrating into the felt material 47 via the oil receiving plate 46, they are applied to the outer peripheral surface of the fixing roller 1.

As described above, according to this embodiment, the oil flowing out from the oil outlet holes 45, 45,... Of the pipe member 44 and flowing down along the guide pieces 51, 51,. The flow-down direction is regulated toward the apex of the lower end of each of 51,. For this reason, even in a situation where the pipe member 44 is inclined, it is possible to apply the oil O to a necessary portion on the surface of the fixing roller 1 by the regulation of the flowing direction, and as a result, It becomes possible to apply the oil O to substantially the entire surface of the fixing roller 1 uniformly and reliably. By making the oil applied to the surface of the fixing roller 1 uniform, the occurrence of the offset can be avoided, and the winding of the recording paper P around the rollers 1 and 2 can be prevented, thereby stably forming a high-quality image. Can be done.

-Modification- Next, a modification of the present invention will be described. This example is a modification of the shape of the guide sheet 5, and other configurations are the same as those of the above-described embodiment. Therefore, only the shape of the guide sheet 5 will be described here.

The guide sheet 5 of the above-described embodiment has a configuration in which one guide piece 51 is arranged corresponding to the position of each oil outlet hole 45 of the pipe member 44. In other words, the center line of the inverted triangular guide piece (the straight line L indicated by the one-dot chain line in FIG.
Guide pieces 4 so that the position of
5, 45,... Were formed.

As shown in FIG. 5, the guide sheet 5 of the present embodiment has oil outflow holes 45, 45,.
, Two inverted triangular guide pieces 51A and 51B are arranged respectively. That is, two inverted triangular guide pieces 51A and 51B are formed adjacent to each other, and the boundary between these guide pieces 51A and 51B (the straight line L indicated by a dashed line in FIG. 5) and the position of the oil outflow hole 45 are aligned. The guide sheet 5 is formed so as to overlap in the vertical direction.

According to this configuration, the number of points at which oil is dropped from the guide sheet 5 can be increased without increasing the number of oil outlet holes 45, and uniform oil O can be spread over almost the entire roller surface. The application can be performed more reliably.

-Other Embodiments- In the embodiment described above, each guide piece 5 of the guide sheet 5
The oil O dropped from 1, 51,... Is once received by the oil receiving plate 46, and the oil O is applied to the outer peripheral surface of the fixing roller 1 via the felt material 47 and the oil applying roller 3. The present invention is not limited to this, and the oil dropped from the guide pieces 51, 51,... May be dropped directly on the outer peripheral surface of the oil application roller.

Further, the configuration in which the oil supply mechanism 4 applies the oil O to the outer peripheral surface of the fixing roller 1 has been described.
The present invention can be applied to a configuration in which oil O is applied to the outer peripheral surface of the pressure roller 2, or to a configuration in which oil O is applied to the outer peripheral surfaces of both rollers 1, 2.

The shape of the guide piece 51 of the guide sheet 5 may be any shape as long as the width dimension gradually decreases toward the lower side, and is not necessarily limited to an inverted triangle.

[0041]

As described above, according to the present invention, the release agent supply means for supplying the liquid release agent for application to the roller surface is provided with a shape for regulating the flow direction of the release agent. Is formed. For this reason, it is possible to apply the release agent to necessary portions of the roller surface regardless of the inclination of the cylindrical body that supplies the release agent. As a result, it is possible to solve the problem that offset is caused or the recording paper is wrapped due to uneven application of the oil to the roller, so that high-quality image formation can be stably performed. Further, it is possible to prevent the oil supply to a part from being excessive and causing oil leakage.

Further, when the guide piece is formed of a material having permeability, it is possible to avoid a situation in which the release agent flowing into the guide piece drops from a portion other than the lower end of the guide piece. In addition, the flow direction of the release agent can be accurately regulated, and the reliability of uniform oil application to the roller can be improved.

Furthermore, when the hole of the cylindrical body is formed on the side where the guide piece is slightly in contact with the upper end of the cylindrical body, most of the release agent flowing out of the hole of the cylindrical body is removed. It is possible to flow in the direction toward the guide piece, and it is possible to avoid a situation in which the release agent that has flowed out of the hole of the cylindrical body drops without flowing through the guide piece, and this also enables uniform oil application to the roller. Can be improved in reliability.

In addition, when a plurality of guide pieces are arranged corresponding to each of the holes in the cylindrical body, the oil from the guide means can be increased without increasing the number of holes in the cylindrical body. The falling point can be increased, and the release agent can be applied to almost the entire surface of the roller more reliably.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a part of a fixing device according to an embodiment.

FIG. 2 is a side view showing a part of the fixing device in a cross section.

FIG. 3 is a side view of a pipe member.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a diagram corresponding to FIG. 3 in a modified example.

FIG. 6 is a diagram corresponding to FIG. 1 in a conventional example.

FIG. 7 is a plan view of a pipe member and its peripheral portion in a conventional example.

8A and 8B are diagrams showing a state in which oil is dropped from a pipe member in a conventional example, wherein FIG. 8A shows a case where the arrangement state of the pipe member is horizontal, and FIG. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 4 Oil supply mechanism (release agent supply means) 44 Pipe member (tubular body) 45 Oil outflow hole 5 Guide sheet 51 Guide piece O Oil (release agent) P Recording paper (sheet material)

Claims (6)

[Claims] 1. A pair of rollers for fixing a developer to a surface of a sheet material while nipping and transporting the sheet material, and a release agent supply unit for supplying a liquid release agent toward at least one surface of the rollers. Wherein the release agent supply means comprises: a cylindrical body extending substantially parallel to a roller to which the release agent is supplied, and having a hole for releasing the release agent; Guide means for causing the release agent flowing out of the hole to flow down, wherein the guide means is formed in a shape such that the width dimension gradually decreases toward the lower side so as to regulate the flow direction of the release agent. A fixing device comprising a guide piece. 2. The fixing device according to claim 1, wherein a plurality of guide pieces are arranged along a roller extension direction. 3. The fixing device according to claim 1, wherein the guide piece is formed of a material having permeability. 4. The fixing device according to claim 1, wherein an upper end of the guide piece is in contact with a side surface of the cylindrical body,
The release agent flowing out of the hole of the cylindrical body is made to flow down, while the hole of the cylindrical body is formed on the side where the guide piece is slightly in contact with the upper end of the cylindrical body. A fixing device. 5. The fixing device according to claim 2, wherein the holes of the cylindrical body are formed at a plurality of positions along the roller extending direction, and each guide piece corresponds to the position of the hole of the cylindrical body. A fixing device, wherein the fixing device is arranged in a position. 6. The fixing device according to claim 2, wherein the holes of the cylindrical body are formed at a plurality of positions along the roller extending direction, and each guide piece corresponds to each of the holes of the cylindrical body. And a plurality of fixing devices.