JPH0527638A - Cleaning device for fixing roller - Google Patents

Abstract

PURPOSE:To remove the toners remaining on a fixing roller and to decrease the wear of the fixing roller surface by providing a cleaning roller which is in pressurized contact with the fixing roller and is connected by a power transmission device. CONSTITUTION:The fixing roller 1 and a pressure roller 2 are brought into pressurized contact with each other and are rotatably mounted. The fixing roller 1 is so disposed with the cleaning roller 3 that the cleaning roller is brought into pressurized contact therewith and is rotated. A gear 4 driven by the driving section of the device is attached to the fixing roller 1. A pinion 5 meshed with the gear 4 and an electromagnetic clutch 6 are attached to the cleaning roller 3. Namely, the diameter of the gear 4 is larger than the diameter of the fixing roller 1 and the diameter of the pinion 5 is smaller than the diameter of the cleaning roller 3. Then, the cleaning roller 3 rotates in the direction where the roller corotates with the fixing roller 1 at the circumferential speed higher than the circumferential speed of the fixing roller 1. The driving of the cleaning roller 3 is released by the electromagnetic clutch 6 when paper is not passed, by which the unnecessary wear of the roller is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roller cleaning device in a fixing device of an image forming apparatus having a fixing roller and a pressure roller which is pressed against the fixing roller.

[0002]

2. Description of the Related Art In a fixing device of an image forming apparatus such as a copying machine or a laser printer, in order to prevent an offset, a system in which application of silicone oil to a fixing roller and oil scraping by a metering blade are combined is generally used. Has been adopted. However, this method has a problem of insufficient durability, in which the fixing roller surface is abraded by the paper dust and toner accumulated on the blade, and the coating on the fixing roller surface is eventually peeled off.

In order to improve the durability of the fixing roller, it is effective to eliminate the peripheral parts of the fixing roller, but at this time, the offset in the fixing roller is not removed and the fixing roller is not removed. The offset is transferred to the transfer paper, which causes a new problem that the image quality is deteriorated.

In order to solve the above-mentioned problems, a roller cleaning system has been proposed in which a cleaning roller is provided which rotates in pressure contact with a fixing roller to remove the toner remaining on the surface of the fixing roller. (Japanese Patent Laid-Open No. 62-22
No. 84). In the system according to this proposal, the cleaning roller rotates at a peripheral speed different from that of the fixing roller and in the opposite direction to remove the toner on the surface of the fixing roller.

[0005]

[Problems to be Solved by the Invention]
In the la cleaning system, the cleaning roller is drivingly connected to the fixing roller via a gear transmission, so that the cleaning roller is constantly driven to rotate during the rotation of the fixing roller. Therefore, the wear of the cleaning roller on the surface of the fixing roller is unavoidable, and the above-mentioned problems caused by this wear occur.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in a roller cleaning system, to remove the toner remaining on the surface of the fixing roller, and to reduce the abrasion of the surface of the fixing roller as much as possible. To do.

[0007]

According to the present invention, there is provided a cleaning roller, which is pressed against a fixing roller and is connected to the fixing roller through a transmission device. The problem is solved by the rotation of the fixing roller via a device, the transmission device being released during idling before and after sheet passing, and during free running, and the cleaning roller circling around with the fixing roller.

Further, in order to solve the above-mentioned problems, the present invention, in addition to the above-mentioned constitution, rotates the cleaning roller in a rotating direction with the fixing roller at the time of paper passing and at a peripheral speed different from that of the fixing roller. Suggest to do.

[0009]

The cleaning roller pressed against the fixing roller is rotated at a peripheral speed difference from that of the fixing roller when the paper is passed, thereby removing the offset toner on the surface of the fixing roller. When the paper is not passed, the driving connection with the fixing roller is released, so that the cleaning roller only runs around the fixing roller due to friction.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the embodiments of the fixing device to which the present invention is applied shown in FIGS.

In FIG. 1, a fixing roller 1 and a pressure roller 2 are rotatably mounted in pressure contact with each other. A heater is provided inside the fixing roller 1, and the toner image is fixed by the transfer paper carrying the toner image passing between the nip between the rollers.

The fixing roller 1 includes a cleaning roller 3
Are also arranged so as to be pressed against each other and rotate. A gear 4 which is rotationally driven by a drive unit of the apparatus is attached to the shaft 1a of the fixing roller 1, and a pinion 5 which meshes with the gear 4 is attached to the shaft 3a of the cleaning roller 3. Further, the shaft 3 a of the cleaning roller 3 has an electromagnetic clutch 6 between the cleaning roller 3 and the pinion 5.
Is installed.

As shown in FIG. 2, the diameter of the gear 4 is determined by the fixing roller.
The diameter of the pinion 5 is larger than that of the cleaning roller 3, and the diameter of the pinion 5 is smaller than that of the cleaning roller 3. As a result, the cleaning roller 3 rotates in the revolving direction with the fixing roller 1 with a speed difference in which the peripheral speed becomes faster than the peripheral speed of the fixing roller 1.

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

When making a copy, the electromagnetic clutch 6 is turned on by the signal of the separation sensor of the apparatus main body only when the transfer sheet is passed through the fixing apparatus, so that the rotation of the fixing roller 1 is rotated by the gear 4 and the pinion. 5 and the electromagnetic clutch 6 to the cleaning roller 3. At this time, as described above, since the cleaning roller 3 rotates faster than the fixing roller 1, the offset toner and the paper dust adhered to the surface of the fixing roller 1 are removed due to the difference in peripheral speed.

In this case, although the cleaning roller 3 has a peripheral speed difference with the fixing roller 1, since it rotates in the direction of rotation with the fixing roller 1, the cleaning roller 3 has a peripheral member such as a cleaning blade. The effect of reducing wear of the fixing roller 1 can be obtained as compared with the above, and cleaning can be performed without impairing the durability of the fixing roller 1.

Since the toner is not offset to the fixing roller 1 when the fixing roller 1 is idling or before or after the sheet is passing, such as during free running, the electromagnetic clutch 6 is generated by the signal from the separation sensor. Turns off. Therefore, at this time, the cleaning roller 3 is rotated around the fixing roller 1, the peripheral speeds of both rollers match, and the frictional wear of both rollers is further reduced.

The timing at which the electromagnetic clutch 6 is turned off is set to a certain time after the transfer paper passes through the separation sensor, for example, 1 to 2 seconds. As a result, the electromagnetic clutch is always on during continuous copying.

The rotation direction of the cleaning roller 3 is not limited to the rotation direction with the fixing roller 1 as shown in the above-described embodiment, but the cleaning roller 3 is changed with the fixing roller 1. It can also be rotated in the opposite direction. At this time, even if the abrasion of the fixing roller 1 at the time of paper passing is slightly increased, the electromagnetic clutch 6 is turned off at the time of non-paper passing, so that the wear at the time of non-paper passing is eliminated. It is also possible to rotate the cleaning roller 3 slower than the fixing roller 1.

[0020]

According to the first aspect of the invention, the drive transmitted to the cleaning roller can be disconnected by the electromagnetic clutch.
The drive of the cleaning roller when the paper is not passing is released, whereby unnecessary wear of the fixing roller when the paper is not passing can be eliminated, and the durability of the fixing roller can be improved.

According to the second aspect of the invention, the cleaning roller removes the offset toner on the surface of the fixing roller due to the difference in peripheral speed with respect to the fixing roller, and the rotation direction of the cleaning roller is rotated around the fixing roller. Since the direction is the direction, the abrasion at the time of passing the paper can be reduced, and the durability of the fixing roller can be further improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a fixing device to which the present invention is applied.

FIG. 2 is an explanatory diagram showing a gear ratio between a fixing roller and a cleaning roller in FIG.

[Explanation of symbols]

1 Fixing roller 3 cleaning roller 4,5 gears 6 electromagnetic clutch

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuhiro Echigo             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Yoshito Ikeda             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh

Claims (2)

[Claims] 1. In a fixing device of an image forming apparatus having a fixing roller and a pressure roller which is pressed against the fixing roller, the fixing roller is pressed against the fixing roller and is connected to the fixing roller via a transmission device. A cleaning roller is provided, and the cleaning roller is rotated by the drive of the fixing roller via the transmission device when the paper is passed. A fixing roller cleaning device characterized by rotating around with the fixing roller. 2. The cleaning roller is a fixing roller when passing a sheet.
The cleaning device for a fixing roller according to claim 1, wherein the cleaning device rotates in the direction of rotation with the roller and at a peripheral speed different from that of the fixing roller.