JPH0635359A - Fixing device - Google Patents

Abstract

PURPOSE:To keep stable fixing action for a long time by making a cleaning roller driven with the rotation of a heating roller when the cleaning roller is not driven and making speed difference between the cleaning roller and the heating roller occur when the cleaning roller is driven. CONSTITUTION:The cleaning roller 20 is always rotatably supported in contact with the heating roller by a roller supporting means, also the roller 20 has a gear 35 on its rear side, and is meshed with a driving gear 37 attached to the driving shaft of a speed variable motor 36 which is a driving source. A roller driving device 40 is constitued so that the roller 20 can be driven with the rotation of the heating roller when the roller 20 is not driven, and the roller 20 is rotated and driven to cause the speed difference in a width direction when the roller 20 is driven. Thus, both the cleaning ability and the long life of the cleaning roller 20 can be satisfactorily attained, and the heating roller can be prevented from being stained for a long time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device applied to an image forming apparatus such as an electrophotographic copying machine or a laser printer.

[0002]

2. Description of the Related Art In recent years, as one of fixing devices of this type, a heating roller and a pressure roller which is brought into pressure contact with the heating roller are provided, and a transfer member such as a sheet is placed between the rollers. A heating roller type fixing device for heating and fusing and fixing a powder image on a transfer member by passing it through is widely put into practical use.

This type of fixing device has a feature that it is possible to perform stable fixing although it has a small structure, but on the other hand, since powder adheres to the surface of the heating roller and stains it, it is removed. A cleaning mechanism is needed to keep it clean.

Conventionally, as this type of cleaning mechanism,
The mainstream is one in which the cleaning felt is simply fixedly contacted with the heating roller, but this has a problem that the cleaning life is extremely short because the contact position is fixed. It was

Therefore, as a cleaning mechanism for extending the cleaning life, a cleaning roller is brought into contact with the surface of the heating roller and the cleaning roller is driven by the heating roller. A roller type cleaning mechanism that cleans the surface of the heating roller by rotating in the opposite direction (against direction) in conjunction with the heating roller or in conjunction with the heating roller. It is being put to practical use.

However, in the roller type cleaning mechanism, the driven type in which the former cleaning roller is driven by the heating roller has a long life but a low cleaning property. On the other hand, the latter type, which rotates the cleaning roller in the opposite direction (against direction) in conjunction with the heating roller, has a high cleaning property, but the heating roller is susceptible to stress at the start of rotation and the life is increased. Short-lived,
There is a problem that the heating roller may be damaged.

[0007]

As described above, the fixing device employing the conventional roller type cleaning mechanism satisfies both the cleaning property and the long life property of the cleaning roller. In addition, there is a problem in that the heating roller cannot be prevented from being soiled for a long period of time, and a stable fixing operation cannot be maintained for a long period of time.

The present invention has been made based on the above circumstances, and is capable of preventing the heating roller from being soiled for a long period of time with a structure that can satisfy both the cleaning property and the long life property of the cleaning roller. An object of the present invention is to provide a fixing device capable of maintaining a stable fixing operation over a period of time.

[0009]

As a first means for solving the above problems, the present invention relates to a heating roller for welding a powder image onto a transfer member and a heating roller for the heating roller. A pressure roller for pressing the transfer member and the heating roller.
A cleaning roller for rolling the surface of the heating roller provided by rolling contact with the surface of the roller, and this cleaning roller.
Roller driving means for enabling the ning roller to be driven according to the rotation of the heating roller when it is not driven, and for driving the ning roller to rotate in the direction of the width of the heating roller when driven. And a control means for controlling the cleaning roller so as to rotate so that a speed difference is generated between the cleaning roller and the heating roller.

As a second means, a heating roller for welding the powder image onto the transfer member, and a pressure roller for pressing the transfer member against the heating roller. A cleaning roller for rolling the surface of the heating roller provided in contact with the surface of the heating roller to keep the surface of the heating roller clean, and the heating roller when the cleaning roller is not driven. Driven by the rotation of the rotor
It is configured to include a roller driving means for rotationally driving in the against direction with respect to the rotational direction of the roller.

[0011]

According to the first means described above, the cleaning roll is
When the roller is not driven, it can be driven according to the rotation of the heating roller, and when it is driven, the cleaning roller is rotationally driven so that a speed difference occurs between the cleaning roller and the heating roller. -It is possible to satisfy both the cleaning property and the long life property of the ning roller, and it is possible to prevent the heating roller from being soiled for a long period of time. This makes it possible to maintain a stable fixing operation for a long period of time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 shows a state in which the fixing device 1 of the present invention is incorporated in the main body 2 of the image forming apparatus.

The fixing device 1 includes a heater lamp 5 as a heat source.
A heating roller (heat roller) 6 having a built-in heater, and a heating roller (press roller) 8 pressed against the heating roller 6 by the urging force of a spring 7. It is a la-type fixing device.

Then, by passing a sheet P as a transfer member between the heating roller 6 and the pressure roller 8, the toner image T as a powder image on the sheet P is fused and fixed. It is like this.

The heating roller 6 and the pressure roller 8 are surrounded by an upper casing 10 and a lower casing 11, and the outside is maximized so as to secure a favorable temperature atmosphere required for fixing. It is structured so that heat cannot escape. Further, on the upper surface side of the upper casing 10, a fuser guard 12 is provided as a safety means for preventing burns in a state of covering the upper casing 10.
Is provided.

Further, paper guides 13 and 14 are arranged in the vicinity of the upstream side of the contact portion between the heating roller 6 and the pressure roller 8, and a front image forming mechanism (illustrated in the figure) is provided via a transport mechanism 15. The leading edge of the sheet P fed from (No) is reliably guided between the heating roller 6 and the pressure roller 8.

Further, in the vicinity of the downstream side of the contact portion between the heating roller 6 and the pressure roller 8, the paper P wound around the heating roller 6 is formed.
Peeling claw 16 that also serves as a guide for peeling a sheet, and the paper guide 1
7 is provided, and the fixed paper P is ejected to the roller pair 1
It is designed to lead to 8.

Further, a roller provided with a cleaning roller 20 made of felt or the like which is in rolling contact with the upper portion of the heating roller 6.
A la-type cleaning mechanism 21 is provided to remove the toner t as powder adhering to the surface of the heating roller 6.

Further, a thermistor 22 as a temperature sensor is provided in contact with the heating roller 6 on the downstream side in the rotational direction of the heating roller 6 from the position where the cleaning roller 20 is provided. The temperature is controlled so that the surface temperature of 6 is detected and the temperature required for fixing is maintained.

Further, as shown in FIG. 1, gears 25 and 26 meshing with each other are attached to one end side of the heating roller 6 and the pressure roller 8 to fix the fixing device 1 to the image forming apparatus. When the gear 26 is assembled in the device body 2, the gear 26 is in mesh with the drive gear 27 on the device body 2 side to receive the driving force. The heating roller 6 rotates in the clockwise direction (direction of arrow a) in FIG. 2, and the pressure roller 8 moves in the direction of the width (arrow b) with respect to the heating roller 6.
Direction).

The driving force of the gear 26 is transmitted to the lower roller 18a of the paper discharge roller pair 18 via the gear group 28. In FIG. 1, reference numeral 30 is a power supply terminal for supplying power to the heater lamp 5, which is the heat source of the heating roller 6. Next, the roller type cleaning mechanism 21 will be described.

As shown in FIG. 1, a cleaning roller 2
No. 0 is supported by a roller supporting means (not shown in detail) so as to always be in rolling contact with the heating roller 6, and
It has a gear 35 on its rear side and is in a state of meshing with a drive gear 37 attached to the drive shaft of a speed-variable motor 36 which is a drive source. Then, a roller driving device 40 as a roller driving means for making the cleaning roller 20 can be driven according to the rotation of the heating roller 6 when it is not driven and for rotating it in the wiz direction when it is driven. I am configuring. The driving operation of the motor 36 of the roller driving device 40 is controlled by a control device 41 as a control means.

As shown in FIG. 3, at the start of copying, the control device 41 inputs the motor output adjustment value stored in the storage section 45 to the arithmetic control section 46 and outputs the clock signal from the clock generation section 47. It is input to the arithmetic control unit 46. The arithmetic control unit 46 outputs the control voltage data to the D / A conversion unit 48, the D / A conversion unit 48 performs analog conversion, and then outputs the control voltage value to the drive circuit 49 of the motor 36. The motor 36 generates a motor speed that is proportional to the control voltage value. Then, the cleaning roller 20 rotates in the same direction as that of the heating roller 6 in the same direction, that is, in the width direction (arrow c direction) so that a speed difference is generated between the cleaning roller 20 and the heating roller 6. . Similarly, until the copy end, the motor output adjustment value stored in the storage unit 45 is output, and the motor rotation speed corresponding thereto is generated. By the cleaning roller 20 which is rotationally driven in this manner, the toner t attached to the surface of the heating roller 6 is removed.

As shown in FIG. 4, the motor rotation speed at the start of rotation is set higher than in other cases, whereby the speed of the cleaning roller 20 at the start of rotation is higher than in other cases. It is designed to rotate at high speed.

FIG. 5 shows a comparison of the cleaning properties of the roller type cleaning mechanism 21 constructed as described above and the conventional type, and FIG. 6 shows a comparison of the life properties. FIG. A in the figure is a conventional driven type in which the cleaning roller is driven by the heating roller, and B in the figure is in the reverse direction (against direction) in conjunction with the cleaning roller in conjunction with the heating roller. A conventional reverse-moving type that rotates is shown, and C in the figure shows the present invention. As is clear from FIGS. 5 and 6, it can be seen that the one according to the present invention can achieve a strong cleaning property and a long life. Therefore,
Contamination of the heating roller 6 can be prevented for a long period of time, which makes it possible to maintain a stable fixing operation for a long period of time.

In the above embodiment, the cleaning roller 20 is rotated in the same direction as the heating roller 6 in the joining direction, that is, in the direction of the arrow (direction of arrow c). As shown in FIG. 7, the cleaning roller 20 can be driven according to the rotation of the heating roller 6 when it is not driven, and is in the reverse direction at the joint with the heating roller 6 when it is driven, that is, against. The same effect can be obtained even if it rotates in the direction (direction of arrow d).

The point is that the cleaning roller 20 can be driven according to the rotation of the heating roller 6 when it is not driven, and a speed difference is generated between the cleaning roller 20 and the heating roller 6 when it is driven. Good. In addition, the present invention is not limited to the above-described embodiment, and can be variously modified.

[0028]

As described above, according to the present invention,
The cleaning roller has a strong cleaning property and a long life. It can clean stains on the heating roller for a long time and can maintain stable fixing operation for a long time. It is possible to provide the device.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a fixing device of the present invention.

FIG. 2 is a schematic configuration diagram showing a state where the image forming apparatus is incorporated in the apparatus main body.

FIG. 3 is an explanatory diagram showing a drive control system of a cleaning roller.

FIG. 4 is a diagram showing a relationship between a motor rotation speed and a cleaning roller speed.

FIG. 5 is a diagram showing a comparison of cleaning properties between the conventional type and the device of the present invention.

FIG. 6 is a view showing a comparison of life between the conventional type and the device of the present invention.

FIG. 7 is an explanatory view showing another embodiment of the present invention.

[Explanation of symbols]

1 ... Fixing device, 6 ... Heating roller, 8 ... Pressing roller, 20
... cleaning roller, 21 ... roller type cleaning mechanism, 36 ... motor, 40 ... roller driving device (roller driving means), 41 ... control device (control means), t ... Toner (powder), T ... Toner image (powder image).

Claims (2)

[Claims] 1. A heating roller for welding a powder image onto a transfer member, a pressure roller for pressing the transfer member against the heating roller, and the heating roller. A cleaning roller for rolling the surface of the heating roller, which is provided by rolling contact with the surface of the heating roller, and a rotation of the heating roller when the cleaning roller is not driven. Roller driving means that can be driven and that is driven to rotate in the direction of the width of the heating roller when driven, and the cleaning roller that connects the heating roller to the cleaning roller. And a control unit that controls to rotate so that a speed difference occurs between the fixing unit and the fixing unit. 2. A heating roller for welding a powder image onto a transfer member, a pressure roller for pressing the transfer member against the heating roller, and a heating roller. A cleaning roller for rolling the surface of the heating roller, which is provided by rolling contact with the surface of the heating roller, and a rotation of the heating roller when the cleaning roller is not driven. A fixing device comprising a roller driving means which can be driven and which is driven to rotate in an against direction with respect to a rotating direction of the heating roller when driven.