JPH06194987A - Fixing device - Google Patents

Abstract

PURPOSE:To provide a fixing device unnecessitating of frequently exchanging a cleaning pad of a fixing roller. CONSTITUTION:A pressure roller 13 abuts on the surface of the fixing roller 11 provided with a heater 12 being a heat source inside. Besides, the cleaning pad 16 abuts on the roller 11. The pad 16 is supported by a holder 17 which is turnable with a shaft 18 as an axis and the holder 17 is turned by the action of a lever 20 provided on the shaft 18. The lever 20 is interlocked with the sliding action of an elevating and lowering machine 21. By the machine 21, the revolving motion of a motor 22 is converted to the motion in a sliding direction. The pad 16 is normally separated from the roller 11 and they are made to abut on each other by rotating the motor 22 at a fixing action time. Besides, both of them are separated by reversely rotating the motor 22 after the finish of the fixing action.

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 applied to an electrophotographic recording device such as a copying machine or a printer and heat-fixes a toner image on a transfer paper.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a conventional general electrophotographic recording apparatus, in which 1 is a belt-shaped photosensitive member and 2 is a roller for rotating and driving a suspended photosensitive member 1 in the X direction in the drawing. Three
Is a charging unit, 4 is an exposure unit, 5 is a developing unit, 6 is a recording sheet, 7 is a transfer unit, 8 is a fixing unit, 9 is a cleaning unit, and 10 is a neutralization L.
ED is shown.

After the photoconductor 1 is charged by the charger 3, the exposure unit 4 irradiates it with a laser beam based on image information to form an electrostatic latent image on its surface. Toner is attached to the electrostatic latent image by the developing device 5 to form a toner image, and then the toner image is transferred to the recording paper 6 by the transfer device 7. The recording paper 6 to which the toner image is transferred is heated by the fixing device 8 and the toner image is fixed and then discharged.
In this way, a hard copy is created. On the other hand, the toner remaining on the photoconductor 1 is collected by the cleaning unit 9,
Further, the residual charge is removed by the charge removing LED 10, so that the photoconductor 1 is ready for the next image formation.

The most common fixing device 8 used in the above electrophotographic recording apparatus is a fixing system using a heat roller. In this system, a recording sheet is sandwiched and pressed at a nip portion between a cylindrical fixing roller 11 having a heater 12 such as a halogen lamp incorporated therein and a pressure roller 13 having a surface coated with heat-resistant rubber. By heating, the toner image is fixed on the recording paper, which is suitable for high-speed specifications.

However, in the fixing method using the heat roller, since the roller is constantly in contact with the unfixed toner, the fixing roller 11 is contaminated. In order to solve this point, in the past, JP-A-2-210380 and JP-A-2-104369 have been proposed.
The techniques described in Japanese Patent Laid-Open No. 2-213889 are known. Especially a cleaning pad made of felt
A method is generally used in which 14 is brought into contact with the fixing roller 11 and the surface of the fixing roller 11 is wiped off.

[0006]

However, in an ordinary electrophotographic recording apparatus, it is very difficult to instantly raise the heater of the fixing roller to a specified temperature. Therefore, even when the image forming operation is not performed, it is necessary to energize the heater to raise it to a certain temperature. In such a standby state, if a cleaning pad that has been used a lot and is heavily soiled is kept in contact with the fixing roller, the toner will stick to the cleaning pad only at the contact portion and conversely stain the fixing roller. May cause stains on the transfer paper.

In such a case, maintenance has been performed by a service person replacing the cleaning pad.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a fixing device capable of always forming a high quality image without requiring frequent replacement of the cleaning member of the fixing roller.

[0009]

In order to achieve the above object, a recording medium on which a toner image is formed is heated and heated by a fixing roller having a heat source and a pressure roller in pressure contact with the fixing roller. In a fixing device for fixing a toner image by applying pressure, the present invention relates to a cleaning unit for contacting the surface of the fixing roller for cleaning, and at least contacting the cleaning unit with the fixing roller during a fixing operation, And a means for separating the fixing operation after the completion of the fixing operation.

A plurality of cleaning means for contacting and cleaning the surface of the fixing roller and at least one cleaning means for contacting during the fixing operation,
And a means for sequentially switching the cleaning member to be brought into contact with the fixing roller.

Further, cleaning means for contacting the surface of the fixing roller for cleaning, a counter for counting the number of recording media on which a toner image is fixed, and a counter for cleaning the cleaning means each time the counter counts a prescribed number of sheets. And a means for changing the contact position with respect to the fixing roller.

[0012]

By adopting the above-mentioned structure, the cleaning means is brought into contact with the fixing roller during the fixing operation to perform cleaning, and the cleaning means is separated from the fixing roller except during the fixing operation. It is possible to prevent the toner from sticking to the surface of the cleaning member at the contact portion with the fixing roller.

By providing a plurality of cleaning means and sequentially switching the cleaning means to be brought into contact with each other, the life of the cleaning means can be extended.

Further, by changing the position where the cleaning means comes into contact with the fixing roller for each predetermined number of fixing sheets, the contact portion between the cleaning means and the fixing roller becomes new during the fixing operation, so that the cleaning means has a long life. Can be realized.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the configuration of the first embodiment of the present invention. The same members as those in the conventional technique shown in FIG. 6 are designated by the same reference numerals. In FIG. 1, 15 is a drive transmission gear that gives a driving force to the fixing roller 11, and 16 is a fixing roller.
11 a cleaning pad that contacts the surface for cleaning, 17 a holder that supports the cleaning pad 16, 18 a shaft that rotatably supports the holder 17, and 19 a shaft
A bearing provided at one end of 18, a lever provided at the other end of the shaft 18, 21 is an elevator that converts rotational motion into linear motion and slides, 22 is a motor, and 23 is an elevator 21 and a motor 22. An endless belt erected between the pair of pulleys 24, 24, a hook 25 having one end connected to the elevator 21 and the other end locked to the lever 20, and 26 a fixing roller 11 heated by the heater 12. The thermistor which measures surface temperature is shown.

The fixing roller 11 is rotationally driven by the rotation of the drive transmission gear 15, while the pressure roller 13 is attached to the fixing roller 11.
Since the fixing roller 11 is pressed so as to form a nip to some extent, the fixing roller 11 rotates following the rotation of the fixing roller 11.

The cleaning pad 16 is made of felt, and is brought into contact with or separated from the surface of the fixing roller 11 by the linear slide operation of the elevator 21. That is, when the motor 22 rotates the pulleys 24, 24, the elevator 2
1 performs a sliding operation, and this sliding operation is performed by lever 20.
The cleaning pad 16 rotates together with the holder 17 by being received by. In addition, this motor 22 changes the phase of the current to 18
Reverse rotation is possible by changing 0 °.
Is rotating normally, the fixing roller 11 and the cleaning pad 16
, And separate from each other in the reverse rotation.

FIG. 2 is a time chart showing the operation of the above-mentioned first embodiment, in which the photosensitive member 1 and the fixing roller are sequentially arranged from the top.
11 and a main motor for driving the developing device 5 (not shown)
Of the fixing roller 11, a time chart of the temperature change of the fixing roller 11, a time chart of a paper feed roller (not shown) that conveys the recording paper 6, and a paper feed feed clutch (not shown) for sending the recording paper 6 to the transfer device 7. The time chart of No.), the time chart of the motor 22, and the time chart of the reverse rotation signal for rotating the motor 22 in the reverse direction are shown.

When the power of the apparatus main body is turned on, the heater 12
Starts heating the fixing roller 11, and as shown in FIG. 2, the fixing roller 11 is controlled to have a temperature of 65 ° C. and enters the standby mode. When the copy start signal is input, the heater
12 further heats the fixing roller 11, and when the temperature of the fixing roller 11 reaches 160 ° C., the motor 22 is driven at timing so that the cleaning pad 16 contacts the fixing roller 11. Then, after the cleaning pad 16 contacts the fixing roller 11, the motor 22 is turned off. After the temperature of the fixing roller 11 reaches 160 ° C., the main motor is turned on, and the paper feeding motor and the paper feeding feed clutch are also turned on to start the paper feeding operation and create a hard copy.

When the copying operation is completed, the main motor and the paper feeding motor are turned off. Further, the temperature of the fixing roller 11 is gradually lowered so as not to drop sharply. At the same time as these operations, a reverse rotation signal is sent to the motor 22, and the cleaning pad 16 is separated from the fixing roller 11. The temperature control of the heater 12 is performed by feedback control using the thermistor 26 as a detection means.

FIG. 3 is a block diagram showing the essential parts of the second embodiment of the present invention. The same members as those in the first embodiment shown in FIG. 1 and the conventional technique shown in FIG. 6 are designated by the same reference numerals.

In FIG. 3, 27 is a first cleaning pad, 28 is a second cleaning pad, 29 is a holder for supporting the first and second cleaning pads 27, 28 in parallel, 30
Indicates a joint connecting the holder 29 and the elevator 21.

The first and second cleaning pads 27 and 28 are
It is positioned so as to sandwich the fixing roller 11, and
One of the two fixing rollers 11
Contact the surface for cleaning. Further, in the standby mode, both pads 27 and 28 are separated from the surface of the fixing roller 11.

During the copying operation, one pad, for example, the first cleaning pad 27 as shown in FIG. Then, in the next copy operation, as shown in FIG. 4, the second cleaning pad 28 is brought into contact and cleaning is performed. In this way, the motor 22 is controlled so as to alternately switch the first and second cleaning pads 27 and 28 for each copy.

FIG. 5 is a block diagram showing the essential parts of a third embodiment of the present invention. The same members as those in the first embodiment shown in FIG. 1 and the conventional technique shown in FIG. 6 are designated by the same reference numerals.

In FIG. 5, reference numeral 31 denotes a long cleaning pad, and the surface of the fixing roller 11 is in contact with one surface of the cleaning pad 31. 32 is a cleaning pad 31
A holder that supports the motor, 33 is a joint that connects the holder 32 and the elevator 21, and 34 is a CPU that controls the rotation operation of the motor 22.
(Central processing unit), 35 is a counter for counting the number of copies.

When the counter 35 counts that the number of copies has reached a predetermined number, for example, 500, a signal is sent from the CPU 34 to the motor 22 to move the cleaning pad 31 by a fixed amount, and the unused portion is fixed to the fixing roller 11. Abut.

By being configured as described above, this embodiment has the following effects.

First, according to the configuration of the first embodiment, in the standby mode, the cleaning pad 16 is separated from the fixing roller 11, and the cleaning pad 16 is brought into contact only during the copying operation. Since it is possible to prevent toner adhesion on the surface of the cleaning pad 16 only at the contact portion caused by the contact of the cleaning pad 16, the cleaning pad 16
Prevents the recording paper from being contaminated by soiling the fixing roller 11, and extends the life of the cleaning pad 16, thus eliminating the need for maintenance by a service person.

In addition to the effects of the first embodiment described above, the configuration of the second embodiment allows the first and second cleaning pads 27 and 28 to be alternately switched for each copy to clean the fixing roller 11. By doing so, the life of the first and second cleaning pads 27, 28 is improved.

Further, with the structure of the third embodiment, in addition to the effects of the first embodiment, a long cleaning pad is provided.
31 is used and the cleaning pad is used after every specified number of copies.
By shifting 31 and bringing a new portion into contact with the fixing roller 11, replacement of the cleaning pad 31 can be reduced as much as possible, and the life can be improved.

[0033]

The present invention constructed as described above has the following effects.

According to the structure of claim 1, the cleaning means is brought into contact with the fixing roller during the fixing operation, and is kept apart from the fixing roller at other times, so that the cleaning means is brought into contact with the fixing roller during the fixing standby time. Since it is possible to prevent the toner from sticking to the cleaning means at the contact portion due to the cleaning, it is possible to prevent the recording paper from being contaminated due to the cleaning means soiling the fixing roller, and to perform maintenance such as replacement of the cleaning means. Can be lengthened.

According to the second aspect of the present invention, the cleaning means is brought into contact with the fixing roller during the fixing operation, and is kept apart from the fixing roller at other times, and a plurality of cleaning means are switched and brought into contact with the fixing roller. ,
Similar to the structure of the first aspect, it is possible to prevent the recording paper from being contaminated, prolong the time for maintenance such as replacement of the cleaning means, and further improve the life of the cleaning means.

According to the third aspect of the invention, since the cleaning unit and the contact position on the fixing roller are shifted for each predetermined number of fixing sheets, one cleaning unit is efficiently used for cleaning, and further, the predetermined number is fixed. Since the unused portion of the cleaning means comes into contact with each fixed number of sheets, it is possible to prevent the recording paper from being contaminated by the contamination of the fixing roller due to the cleaning means, to reduce the replacement of the cleaning means as much as possible, and to improve the service life. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a fixing device according to a first exemplary embodiment of the present invention.

FIG. 2 is a time chart explaining the operation of an electrophotographic recording apparatus using the fixing device of FIG.

FIG. 3 is a configuration diagram showing a main part of a fixing device according to a second embodiment of the invention.

FIG. 4 is a configuration diagram showing a main part of a fixing device according to a second embodiment of the invention.

FIG. 5 is a configuration diagram showing a main part of a fixing device according to a third embodiment of the invention.

FIG. 6 is a configuration diagram showing a configuration of a conventional general electrophotographic recording apparatus.

[Explanation of symbols]

1 ... Photosensitive member, 6 ... Recording paper, 7 ... Transfer device, 8 ... Fixing device, 11 ... Fixing roller, 12 ... Heater, 13 ... Pressure roller, 16, 31 ... Cleaning pad, 17, 29, 32 ... Holder, 18 ... Shaft, 20 ... Lever, 21 ... Elevator,
22 ... motor, 23 ... endless belt, 24 ... pulley,
25 ... Hook, 27 ... First Cleaning Pad, 28 ...
Second cleaning pad, 30, 33 ... Joint, 34
... CPU (Central Processing Unit), 35 ... Counter.

Claims (3)

[Claims] 1. A fixing device having a fixing roller having a heat source and a pressure roller in pressure contact with the fixing roller, for fixing a toner image by heating and pressurizing a recording medium on which a toner image is formed, Cleaning means for contacting with the surface of the fixing roller to clean it; and means for contacting the cleaning means with the fixing roller at least during the fixing operation and separating after the completion of the fixing operation. And fixing device. 2. A fixing device for fixing a toner image by heating and pressing a recording medium on which a toner image is formed, the fixing device having a fixing roller having a heat source and a pressure roller in pressure contact with the fixing roller, A plurality of cleaning means for contacting and cleaning the surface of the fixing roller; and means for contacting at least one cleaning means during the fixing operation and sequentially switching the cleaning member to contact the fixing roller. And fixing device. 3. A fixing device for fixing a toner image by heating and pressing a recording medium on which a toner image is formed, the fixing device having a fixing roller having a heat source and a pressure roller in pressure contact with the fixing roller, Cleaning means for contacting and cleaning the surface of the fixing roller, a counter for counting the number of recording media on which a toner image is fixed, and a counter for contacting the fixing roller with the cleaning means each time the counter counts a prescribed number. A fixing device comprising means for changing a contact position.