JP3243380B2 - Fixing device cleaning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional fixing device cleaning device of this type is a fixing roller having at least a pair of heat fixing rollers 1 and 2 opposed to a toner carrying surface and having a built-in heater 6. 1, a pressure roller 2 in contact with the fixing roller 1, and a cleaning roller 3 in contact with the fixing roller 1 having the same or lower releasability from toner than the fixing roller 1, and a comparison with the cleaning roller 3 And a backup roller 4 which has low releasability from toner and is in contact with the cleaning roller 3. The cleaning device prevents the toner from being offset from the fixing roller 1. Reference numeral 5 denotes a sheet.

[0003]

However, with such a fixing device cleaning device, it is impossible to prevent the occurrence of offset to a satisfactory degree.
In particular, there is a problem that it is impossible to prevent the occurrence of an offset due to reverse rotation from the backup, which occurs remarkably when the image forming apparatus starts up in the morning.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional fixing device cleaning device and to prevent occurrence of offset so as to be satisfied. An object of the present invention is to provide a fixing device cleaning device that can prevent the occurrence of an offset due to reverse rotation from a backup which sometimes occurs remarkably.

[0005]

In order to achieve the above object, the present invention is directed to a cleaning roller in contact with at least a fixing roller opposed to at least a toner carrying surface of a heat fixing roller pair. And a fixing device cleaning device having a backup roller in contact with the cleaning roller, wherein a bias is applied to the cleaning roller, and the charge removing member is provided so as to be able to contact and separate from the cleaning roller. It is a feature. According to a second aspect of the present invention, in the first aspect of the present invention, the charge removing member is provided so as to contact the cleaning roller at the time of pre-rotation and to be separated at the time of paper passing.

[0006]

In the first aspect of the present invention, when the toner has a negative polarity, a bias is applied to the cleaning roller to charge the cleaning roller to a positive polarity opposite to the polarity of the toner. The toner having a polarity is attached to the cleaning roller, or the cleaning roller is electrically set to ± 0 by the charge removing member, so that the toner and paper dust can be easily moved from the fixing roller to the cleaning roller. According to the invention described in claim 2, by contacting the charge removing member with the cleaning roller during the pre-rotation, the layer of toner and paper dust collected by the backup roller, which is significantly generated when the image forming apparatus rises in the morning, It is possible to prevent the occurrence of offset due to reverse transfer to the fixing roller, and to improve the durability of the charge eliminating member by separating the charge eliminating member from the cleaning roller during normal paper feeding.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In each embodiment shown in the drawings, the same parts as those of the above-mentioned conventional fixing device are denoted by the same reference numerals, and description thereof will be omitted. In the first embodiment of the present invention shown in FIGS. 1 and 2, the fixing roller 1 is formed by covering an aluminum core 11 with a fluorine resin layer 12 such as Teflon, and the pressure roller 2 is formed by covering the aluminum core 13. It is formed by covering with a rubber layer 14 made of silicon rubber. A high voltage power supply 16 is connected to the cleaning roller 3, and a thermistor 17 is brought into contact with the surface of the fixing roller 1. The temperature is maintained. In such things,
As shown in FIG. 2, when the toner has a negative polarity, a bias is applied to the cleaning roller 3 by the high voltage power supply 16 to charge the cleaning roller 3 to a positive polarity opposite to the polarity of the toner. Attach to 3.

In the second embodiment shown in FIG. 3, a charge removing member 18 is brought into contact with the cleaning roller 3 so that the cleaning roller 3 is electrically set to ± 0 and is not charged, thereby removing toner and paper dust. It can be easily moved from the fixing roller 1 to the cleaning roller 3.

In the third embodiment shown in FIG. 4, a static elimination member 18 is brought into contact with an end 19 of the cleaning roller 3 excluding a width portion through which paper can pass, whereby toner and paper dust are directly applied to the static elimination member 18. Adherence is prevented.

In a fourth embodiment shown in FIGS. 5 and 6, a charge removing member 18 is provided on the cleaning roller 3 so as to be able to contact and separate therefrom, and the charge removing member 18 is pivotally mounted on a machine frame (not shown).
23 is attached to one end of a lever 21 pivotally supported in the middle, and SOL 22 is attached to the other end of the lever 21.
The other end of the spring 25 having one end attached to the machine frame is connected to the middle of L22. In such a case, as shown in FIG. 5, by contacting the charge removing member 18 with the cleaning roller 3 during the pre-rotation, the toner and paper collected by the backup roller 4 which is significantly generated when the image forming apparatus starts up in the morning are collected. This prevents the powder layer 24 from being reversely transferred to the fixing roller 1 and causing an offset, and during normal paper passing, the SOL
By turning on 22 and separating the charge removing member 18 from the cleaning roller 3 (FIG. 6), the durability of the charge removing member 18 is improved.

[0011]

The present invention is as described above, and the invention according to claim 1 comprises a cleaning roller contacting at least a fixing roller opposed to at least a toner carrying surface of a heat fixing roller pair, and a backup roller contacting the cleaning roller. In the fixing device cleaning device, a bias is applied to the cleaning roller, and the static elimination member is provided so as to be able to contact and separate from the cleaning roller. The cleaning roller is charged oppositely to the polarity of the toner, or is discharged by a discharging member,
There is an effect that toner and paper dust on the fixing roller can be made to adhere to the cleaning roller, and occurrence of offset can be prevented. According to a second aspect of the present invention, in the first aspect of the invention, the charge removing member comes into contact with the cleaning roller during the pre-rotation and separates when the sheet is passed, so that the image forming apparatus is particularly started up in the morning. By not charging the cleaning roller at times, toner and paper dust can be easily moved from the fixing roller to the cleaning roller, and the toner and paper dust collected by the backup roller, which is significantly generated, is reversely transferred to the fixing roller. This has the effect of preventing the occurrence of the offset phenomenon and improving the durability of the charge eliminating member by separating the charge eliminating member from the cleaning roller during normal sheet passing.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment of the present invention.

FIG. 2 is a front view showing an operation state of the above.

FIG. 3 is a front view similar to FIG. 2 of the second embodiment.

FIG. 4 is a partial perspective view of the third embodiment.

FIG. 5 is an operation explanatory view of the fourth embodiment.

FIG. 6 is another operation explanatory view of the above.

FIG. 7 is a front view similar to FIG. 1 of a conventional example of a cleaning device of the same type as the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Cleaning roller 4 Backup roller 5 Paper 16 High voltage power supply 18 Static elimination member 19 End 21 Lever 22 SOL 23 Axis 25 Spring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (2)

(57) [Claims] A biasing means for applying a bias to the cleaning roller in a cleaning device of a fixing device having a cleaning roller contacting at least a toner carrying surface of the thermal fixing roller pair and a backup roller contacting the cleaning roller. A cleaning device for the fixing device, wherein the static elimination member is provided so as to be able to contact and separate from the cleaning roller. 2. The cleaning device for a fixing device according to claim 1, wherein the static elimination member is provided so as to be in contact with the cleaning roller at the time of pre-rotation and to be separated at the time of paper passing.