JP2005084058A - Fixing device and image forming apparatus using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device which has in it a conveyance path disposed without running through a nip, as a regular conveyance path, formed by a fixing rotor or a pressure rotor, passes a member from outside and thereby removes offset toner and impurities in a paper non-contact area out of the fixing device without maintenance by a service man, and ensures the extended life of a fixing part, and improved maintenance period, cost performance and image quality by simple cleaning, and to provide an image forming apparatus using the fixing device. <P>SOLUTION: The fixing device includes: the fixing rotor 11 whose surface is heated by a heat source 17; the pressure rotor 13 which is firmly pressed against the fixing rotor 11 with suitable contact pressure in order to fix images to transfer paper P; a cleaning roller 14 which is firmly pressed against the fixing rotor 11 in order to remove matter sticking to the surfaces of the fixing rotor 11 and the pressure rotor 13. The fixing device is provided with the nip, as the regular conveyance path, formed by the fixing rotor 11 or the pressure rotor 13, and at least one conveyance path disposed without running through the nip. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fixing device that can be cleaned in an electrophotographic apparatus such as a copying machine, a facsimile machine, and a printer, and an image forming apparatus using the fixing device.

A technique for cleaning a fixing rotating body in an electrophotographic apparatus such as a copying machine, a facsimile, or a printer is known (for example, see Patent Documents 1 and 2).
Patent Document 1 discloses a method for cleaning a fixing rotator. At that time, a fixing roller is rotated reversely by a fixing knob, and a cleaning sheet enters a nip portion between a fixing roller and a pressure roller to be separated. The stuck matter stuck on the contact portion of the nail, the thermo switch, and the thermistor is peeled off, transferred to the cleaning sheet at the nip portion, and removed.
Patent Document 2 discloses a fixing cleaning device and a fixing roller collecting method using the fixing device. In this case, the fixing cleaning device attaches the surface layer of the fixing roller to the winding shaft and the unwinding shaft, respectively. The web containing oil wound around at least one of the shafts is pressed by a pressing member for cleaning.
In this fixing cleaning device, the web is sequentially provided with a cleaning section for cleaning dirt adhering to the surface of the fixing roller in the winding direction.
JP 05-188814 A JP 09-006174 A

However, in the electrophotographic image forming apparatus, the toner is melted and fixed to the transfer material in the fixing unit. At this time, not all of the toner adheres to the transfer material. Adheres to the fixing member side, and the toner on the unfixed image is more easily adhered than the fixing member, which causes a further offset phenomenon.
In order to solve such a problem, a fixing device having a cleaning member that is pressed against the rotating body for fixing and a rotating body for pressing in order to remove deposits on the surface of the rotating body for pressing is generally used.
However, since the cleaning member used here is worn or contaminated, maintenance such as replacement of parts or units every appropriate period is required. Further, in the normal paper transport path, the paper itself cleans offset toner and impurities to some extent, but in other parts of the non-transport path that do not come into contact with the paper (such as a cleaning member), the offset toner and impurities remain attached.
Accordingly, an object of the present invention is to provide a conveyance path in the fixing device that passes through a portion other than the nip formed by the fixing rotator or the pressure rotator, which is a normal conveyance path, in order to solve the above problems. By passing a member from the outside, offset toner and impurities that do not come into contact with the transfer paper can be removed outside the fixing device without maintenance by a serviceman, extending the life of the fixing unit and simplifying cleaning It is an object of the present invention to provide a body wearing apparatus that improves the maintenance period, cost performance, and image quality, and an image forming apparatus using the same.

In order to solve the above-mentioned problems, in the invention described in claim 1, the fixing rotator whose surface is heated by a heat source and the fixing rotator are pressed against the fixing rotator with an appropriate contact pressure for fixing on the transfer paper. A fixing rotator, and a fixing roller that includes a cleaning roller that is pressed against the fixing rotator to remove deposits on the surface of the fixing rotator and the pressing rotator. The main feature is a fixing device provided with at least one conveyance path that passes through a nip portion formed by a fixing rotator or a pressure rotator that is a conveyance path of the toner and a portion other than the nip portion.
According to a second aspect of the present invention, the fixing device according to the first aspect is characterized in that a conveyance path other than the normal conveyance path passes through a nip portion formed between the fixing rotator and the cleaning roller. And
According to a third aspect of the invention, the fixing device according to the second aspect is characterized in that the fixing cleaning mode can be started by a signal from an operation unit of the image forming apparatus or a printer.
According to a fourth aspect of the present invention, after the adhering substance removing member is adsorbed by applying a bias to the fixing belt, the adhering substance removing member is moved between the fixing belt and the cleaning roller by rotating the fixing belt. The fixing device according to claim 2, wherein a nip portion formed therebetween is passed through is a main feature.
According to a fifth aspect of the present invention, an image forming apparatus using the fixing device according to the first to fourth aspects is the main feature.

According to the first aspect of the present invention, there is provided a transport path that passes through the fixing device which is a normal transport path other than the nip portion formed by the fixing rotator or the pressurizing rotator in the fixing device, and the normal member is passed by passing the member from the outside. The offset toner and impurities that do not come into contact with the paper other than the paper transport path can be removed outside the fixing device without maintenance by a serviceman, and the maintenance period, cost performance, Image quality can be improved.
According to the second aspect of the present invention, a conveying path for passing the nip portion between the fixing rotator and the cleaning roller is provided separately from the conveying path that normally conveys the nip portion between the fixing rotator and the pressure rotator. Adhering material adheres to the adhering material removing member that is transported and discharged through this transport path, and cleaning the cleaning roller to improve the maintenance period, cost performance, and image quality by extending the cleaning roller life and simplifying cleaning. Can do.
According to the third aspect of the present invention, the adherence on the cleaning roller is caused to adhere to the adhering matter removing member that is transported and discharged through the transport path in response to a signal issued from a user or a service person such as the fixing cleaning mode. Cleaning can improve the maintenance period, cost performance, and image quality by extending the life of the cleaning roller and simplifying cleaning.
According to the fourth aspect, the adhering matter removing member is formed between the fixing belt and the cleaning roller by rotating the fixing belt after adsorbing the entire adhering matter removing member by applying a bias to the fixing belt. Pass through the nip.
As a result, the deposit on the cleaning roller adheres to the deposit removing member that is transported and discharged through this transport path. By cleaning the cleaning roller, the cleaning roller has a longer service life, simplified cleaning, and maintenance performance and cost performance. The image quality can be improved.
According to the fifth aspect of the present invention, the offset toner and impurities in the portion other than the normal paper conveyance path that do not come into contact with the paper can be removed outside the fixing device without maintenance by a serviceman, and the life of the fixing unit can be extended and simplified. It is possible to provide an image forming apparatus that achieves an improvement in maintenance period, cost performance, and image quality due to cleaning.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the basic configuration of the entire system of the present invention. On the surface of the transfer paper P fed from the paper feed tray 1 or the manual feed tray 2, an unfixed image formed by the image forming unit 30 such as development / transfer is transferred by the transfer paper transfer roller 3.
The transfer paper P on which the unfixed image is formed is further sent to the fixing unit 10 by the conveying belt 4 and is added to the fixing roller 11 driven or driven inside the fixing belt 12 whose surface is heated by a heat source such as a heater. By passing through the nip formed by the pressure roller 13, it is fixed on the surface (of the transfer paper) and becomes a semi-permanent image, passes through the main body discharge unit 5, and is discharged to the discharge tray 6.
FIG. 2 is a schematic diagram showing the basic configuration of the fixing device according to the present invention. The fixing belt 12 spanned between the fixing roller 11 and the heating roller 19 is stretched with an appropriate pressure by a pressing means 16 such as a spring through a tension roller 15 positioned between the rollers 11 and 19.
The fixing roller 11 is brought into pressure contact with the pressure roller 13 by another pressure unit to form a necessary nip width. In order to heat the surface of the fixing belt 11, a heat source 17 such as a heater is provided in at least one of the fixing roller 11 or the heating roller 19, and a similar heat source 18 is provided in the pressure roller 13 as necessary. To heat each surface.
With this pressure and heat, the transfer paper P on which an unfixed image is placed can form a semi-permanent image as it passes through the nip between the fixing roller 11 and the pressure roller 13.
In the fixing unit, the toner is melted and fixed to the transfer paper. However, not all of the toner adheres to the transfer paper, but a part of the toner adheres to the fixing belt 12. In order to remove this deposit, the cleaning roller 14 is brought into pressure contact with the fixing belt 12.

FIG. 3 is a schematic view showing a state in which the deposit removing member is passed through the nip portion between the fixing belt and the cleaning roller. The deposit removing member 20 for removing the deposit 21 on the cleaning roller 14 is passed through the nip portion between the fixing belt 12 and the cleaning roller 14.
With this configuration, the deposit 21 on the cleaning roller 14 can be removed by the deposit removing member 20 that passes through the nip portion between the fixing belt and the cleaning roller.
At this time, the deposit removing member 20 that passes through the nip portion preferably has a releasability lower than that of the cleaning roller 14, and as the deposit removing member 20, for example, white paper (copy paper) or a cleaning sheet passes through the nip portion. It is also preferable in terms of conditions.
FIG. 4 is a schematic view showing a first modification of the fixing device according to the present invention. FIG. 5 is a flowchart for explaining the operation in the cleaning mode.
In FIG. 4, the deposit removing member 20 for removing deposits on the cleaning roller 14 is transported to the nip portion between the fixing belt 12 and the cleaning roller 14 through the same transport path as the transfer paper P having an unfixed image. Is difficult.
For this reason, when passing the transfer paper P having an unfixed image, it is transported from a to b, and when passing through the deposit removing member 20 for removing the cleaning roller deposit, it is transported from c to d. The transfer path is switched by rotating the guide plate 22b.
In FIG. 5, first, in a copy standby state, the user or service person selects the cleaning mode (S1, 2), whereby the guide plate 22b is moved to the position a in FIG. 4 by means of a solenoid or the like (S3). A conveyance path for allowing the removal member 20 to pass through the nip portion between the fixing belt 12 and the cleaning roller 14 is secured.
Further, the guide plate 22c also guides the entry and discharge into the nip portions of the passage path in order to make it easier for the deposit removing member 20 to pass through the transport paths c and d. The guide plate 22c also has a heat retention effect by covering the upper part of the fixing device. Next, the fixing unit rotating body (superheated roller) 19 is reversely rotated (S4), and the adhering matter 21 on the cleaning roller 14 is removed by passing the adhering matter removing member 20 (S5).
At this time, the fixing-side safety device (therm stud or the like) and temperature detection means (thermistor or the like) are installed inside the fixing belt, for example, so as not to affect the transportability of the deposit removing member 20.

FIG. 6 is a schematic view showing a first modification of the fixing device according to the present invention. FIG. 7 is an enlarged view of a main part of FIG. FIG. 8 is a flowchart for explaining the operation in the cleaning mode.
In the present embodiment, the paper discharge sensor 24 is disposed on the discharge side of the nip portion between the fixing roller 11 and the pressure roller 13, and the separation claw 23 is disposed on the downstream side of the nip portion on the peripheral surface of the fixing roller 11. To do. The tension roller 15 is configured so that a bias can be applied from a power source 25.
6 to 8, first, a cleaning mode is selected at the time of copying standby (S10). In this cleaning mode, the paper discharge sensor 24 senses the deposit removing member 20 for the first time (S11), and at the same time, the fixing belt 12 is stopped (S12).
At this time, the distance x from the tip f of the deposit removing member 20 and the nip formed by the fixing belt 12 and the pressure roller 13 is a distance l along the fixing rotator (fixing roller) 11 from the nip to the fixing separation claw 23. Compared to be shorter (l> x). The distance x can be determined by the distance L from the nip portion to the paper discharge sensor 24 and the reaction time of the paper discharge sensor 24.
Next, a bias is applied to the fixing belt 12, and the deposit removing member 20 is attracted to the fixing belt 12 by electrostatic force (FIG. 7). As a bias application method, a tension roller 15 provided with a power supply 25 is used to apply the bias to the fixing belt 12. At this time, the fixing belt 12 is made conductive. (Bias is released except in the cleaning mode).
Then, the fixing belt 12 is rotated in reverse by an integral multiple to remove the deposit on the cleaning roller, and control is performed so that the deposit removing member 20 comes to substantially the same position as before the reverse rotation when stopped.
Finally, the adhering matter removing member 20 and the fixing belt 12 adsorbed by the electrostatic force are released by separating the bias so that the fixing belt 12 is in the same state as in FIG. The removing member 20 is discharged from the fixing device 11.
At this time, the tip f of the deposit removing member 20 is controlled so that the distance from the nip formed by the fixing belt 12 and the pressure roller 13 is x, so that it is not sandwiched between the separation claw 23 and the fixing belt 12. In addition, the separation function of the separation claw 23 works, and also the separation of the curvature of the fixing belt 12 assists the discharge so that no jamming occurs.
At this time, the fixing side safety device (therm stud or the like) and the temperature detection means (thermistor or the like) 26 are installed inside the fixing belt, for example, so as not to affect the transportability of the member.

1 is a schematic diagram showing the basic configuration of the entire system of the present invention. 1 is a schematic diagram showing a basic configuration of a fixing device according to the present invention. Schematic which shows the state which has passed the deposit | attachment removal member in the nip part between a fixing belt and a cleaning roller. FIG. 6 is a schematic diagram showing a first modification of the fixing device according to the present invention. The flowchart explaining operation | movement of cleaning mode. FIG. 6 is a schematic diagram showing a first modification of the fixing device according to the present invention. The principal part enlarged view of FIG. The flowchart explaining operation | movement of cleaning mode.

Explanation of symbols

P transfer paper, 10 fixing device (unit), 11 fixing roller (fixing rotating body), 12 fixing belt (fixing portion rotating body), 13 pressure roller (pressure rotating body), 14 cleaning roller, 15 tension roller, 17 Heat source (heater for fixing belt), 20 deposit removal member, 21 deposit on cleaning roller

Claims (5)

  A fixing rotator whose surface is heated by a heat source, a pressurizing rotator pressed against the fixing rotator with an appropriate contact pressure for fixing on the transfer paper, the fixing rotator, and the pressurizing member In a fixing device including a cleaning roller pressed against the fixing rotator in order to remove deposits on the surface of the rotator, a nip formed by the fixing rotator and the pressure rotator as a normal conveyance path. In addition to a transport path that passes through the nip, at least one transport path that passes through other than the nip portion is provided.   The fixing device according to claim 1, wherein a conveyance path other than the normal conveyance path passes through a nip portion formed between the fixing rotator and the cleaning roller.   The fixing device according to claim 2, wherein the fixing cleaning mode can be started by a signal from an operation unit of the image forming apparatus or a printer.   A nip portion formed between the fixing belt and the cleaning roller is formed by rotating the fixing belt after adsorbing the entire adhering material removing member by applying a bias to the fixing belt. The fixing device according to claim 2, wherein the fixing device is passed.   An image forming apparatus using the fixing device according to claim 1.

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