JP3593199B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus using an electrophotographic process, such as a copier, a printer, and a facsimile machine, and more particularly, to a heating roller and a pressure roller cleaning mechanism that constitute a fixing device that fixes a transfer sheet holding unfixed toner. Things.
[0002]
[Prior art]
2. Description of the Related Art In an image forming apparatus using an electrophotographic process, such as a copying machine, a printer, and a facsimile machine, a toner image formed on a photoreceptor is transferred onto transfer paper, and the transfer paper is then transferred to a fixing device. The toner image is fixed by heating and pressing. The fixing device includes a heating roller provided with a heater, and a pressure roller that presses the transfer paper passing through the nip portion by pressing against the heating roller. Since the surface of the heating roller is a surface to which the unfixed toner comes in contact, a process for enhancing the releasability is performed by a fluorine resin layer or the like. However, when a large number of sheets are fixed, the toner adheres and deposits. Also, toner adheres to the pressure roller from a heating roller or the like. If toner adheres to these rollers, problems such as poor fixing and back stains are caused. Therefore, conventionally, various cleaning means for removing foreign matters such as toner adhered to these rollers have been developed. Various types of cleaning means have been developed, such as a roller that is made of a material such as felt and slidably contact a heating roller, and a roller that has a rough surface that is pressed against a pressure roller. I have. However, since all the cleaning means are located on the peripheral surface avoiding the nip portion of each of the heating roller and the pressure roller, other members such as a casing become obstacles and workability at the time of maintenance of the cleaning means is reduced. It was not good. Further, as can be generally said of conventional fixing devices, when a jam occurs in the fixing device, a paper discharge member group such as a paper discharge roller becomes an obstacle, so that the jam processing is not easy.
[0003]
[Problems to be solved by the invention]
That is, FIGS. 4A and 4B show a configuration around a conventional fixing device. A sheet discharging device 2 is connected to a sheet discharging side of the fixing device 1 so as to be openable and closable about a fulcrum 3. The fixing device 1 includes a heating roller 5 having a built-in heater 4, a pressure roller 6 in pressure contact with the heating roller 5, and a cleaning roller 7 in pressure contact with the pressure roller 6. The paper discharge device 2 has a paper discharge roller 8 and a guide plate 9. At the time of maintenance of the fixing device 1 and jam clearance, the paper discharge device 2 is opened around the fulcrum 3 as shown in FIG. However, as shown in the figure, since the cleaning roller 7 is located, the space for clearing the jam at this time is extremely narrow, and the workability is poor.
[0004]
The present invention has been made in view of the above, by providing a retractable cleaning roller as a cleaning means to the paper discharge apparatus which is openably arranged on the sheet discharging side of the fixing device, opens the paper discharge device When the fixing device is discharged, the discharge side of the fixing device is opened to form a space, and the space can be used to perform maintenance (cleaning and replacement work) of the fixing device and the discharge device, and to perform a jam process. The purpose of the present invention is to protect workers from the cleaning roller and to enhance safety .
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a fixing device that includes a heating roller and a pressure roller, receives a transfer sheet holding an unfixed toner image between the two rollers, and fixes and discharges the toner image on the transfer sheet. A fixing device, a guide plate, and a paper discharge roller. The fixing device is pivotally supported on the discharge side of the fixing device to be openable and closable with respect to the fixing device. A sheet discharging device for discharging the transferred toner image-fixed transfer sheet to the outside through the guide plate and a sheet discharging roller, wherein the sheet discharging device includes a heating roller of the fixing device. Alternatively, a cleaning roller for cleaning the pressure roller and an advance / retreat mechanism for moving the cleaning roller forward / backward are provided, and the forward / backward mechanism is provided when the sheet discharging device is closed with respect to the fixing device. The cleaning roller is pressed against the heating roller or the pressure roller by the first spring to enable cleaning, and when opened to the fixing device, the cleaning roller is concealed by the guide plate by the second spring. It is configured to be retracted to a position.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. FIGS. 1A and 1B are basic configuration diagrams of a fixing device and a paper discharging device, which are main parts of the image forming apparatus of the present invention, and a paper discharging device 2 has a fulcrum 3 on the paper discharging side of the fixing device 1 . It is connected so that it can be opened and closed around the center. The fixing device 1 includes a heating roller 5 having a built-in heater 4 and a pressure roller 6 that is in pressure contact with the heating roller 5. The paper discharging device 2 includes a paper discharging roller 8, a guide plate 9, and a cleaning roller 10 . Position of the cleaning roller 10 is set so as to press the pressure roller 6 when the closed state discharge device as shown in FIG. 1 (a), pivoted rotatably by a casing or the like of the paper discharge apparatus 2 I do.
[0007]
In the above configuration, when the cleaning roller 10 is in the closed state in FIG. 1A, the cleaning roller 10 is in pressure contact with the pressure roller 6, so that the rotation of the heating roller 5 causes the pressure roller 6 to rotate. At this time, the cleaning roller 10 can also be rotated to perform cleaning. On the other hand, when the paper discharge device 2 is opened around the fulcrum 3 as shown in FIG. 3B, the cleaning roller 10 is largely separated from the pressure roller 6, so that a large jam clearance is performed on the paper discharge side of the fixing device 1. A space is formed, and the jam removal and maintenance workability are improved. Although the pressure roller 6 is shown as an object to be cleaned by the cleaning roller 10 in FIG. 1, the cleaning roller 10 may be disposed above the sheet discharging device 2 so as to be in pressure contact with the heating roller 4. Further, two cleaning rollers may be simultaneously arranged so as to be in pressure contact with both rollers 4 and 6. This is the same in the following FIG .
[0008]
FIGS. 2A and 2B are explanatory diagrams of the configuration and operation of the embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and a duplicate description will be omitted. When the sheet discharging device is closed, the cleaning roller 10 is pressed against the pressure roller 6 by a spring 15 as shown in FIG. 2A, and when the sheet discharging device is opened, the cleaning roller 10 is connected to the sheet discharging device 2 as shown in FIG. It is characterized in that it is configured to be retracted inside (position concealed by the guide plate 9). As a mechanism for moving the cleaning roller 10 in such a manner, for example, an advancing / retreating mechanism 20 as shown in FIGS. 3A and 3B is used. The advancing / retracting mechanism 20 includes an operating piece 22 rotatably supported at an appropriate position of the sheet discharging device 2 around a shaft 21, the spring 15, a retreating spring 23, and a stopper 24 provided on the fixing device 1 side. Etc.
[0009]
The upper end portion 22a of the action piece 22 is urged clockwise by a retreat spring 23 (F2) on the back surface thereof, so that the lower end 22b presses the cleaning roller 10 in the retreat direction. The lower end 22b is in contact with the block 25 supporting the shaft 10a of the cleaning roller 10 on the rear surface, and the block 25 is urged in the counterclockwise direction by the spring 15 (F1) to press the cleaning roller 10. It is pressed against the roller 6. The shaft 10a of the cleaning roller 10 is supported by a casing or the like of the sheet discharging device so as to be able to advance and retreat in the direction of the arrow in FIG. The cleaning roller 10 may be rotatably engaged with the shaft 10a, or may be configured to rotate integrally with the shaft 10a. When the shaft 10a and the roller 10 rotate integrally, the block 25 also serves as a bearing for the shaft 10a. The relationship between the pressing force F1 of the spring 15 and the pressing force F2 of the spring 23 is set so that F1 <F2.
[0010]
In the configuration of FIG. 2 , when the sheet discharging device 2 is closed with respect to the fixing device 1 as shown in FIG. 2A, the stronger spring is used as shown in FIG. Since the force for urging the action piece 22 in the clockwise direction by 23 is reduced by the stopper 24 on the fixing device side, the action piece 22 cannot be rotated clockwise beyond the illustrated position. On the other hand, since the block 25 is pressed against the back surface of the lower end 22b of the action piece 22 by the weaker spring 15, the cleaning roller 10 can maintain the state pressed against the pressing roller 6 as shown in FIG. it can. On the other hand, when the paper discharge device 2 is opened as shown in FIG. 2B, the locking force of the stopper 24 is lost, and the stronger spring 23 rotates clockwise around the shaft 21. This makes it possible to move the cleaning roller 10 against the spring 15 in the retreating direction shown by the arrow in FIG. Therefore, the cleaning roller 10 has been moved to the retracted position when the sheet discharging device 2 is opened from the closed position by a predetermined angle in the opening direction.
[0011]
In the present embodiment, the reason why the cleaning roller 10 provided in the paper discharge device 2 is concealed inside the paper discharge device when the paper discharge device is opened, particularly, in the shadow of the guide plate 9 is that the cleaning roller 10 is burned by a maintenance person. This is because if the sheet is heated to such an extent that it is exposed from the opening of the sheet discharging device, it may be accidentally touched to cause an accident. As described above, the paper discharge device 2 is retracted to the open position together with the cleaning roller 10, so that a jam clearance space is widened and workability such as maintenance is improved.
[0012]
1, 2, and 4, the members such as the rollers 5, 6, 8, and 10, and the guide plate 9 are hidden behind the casing of the fixing device 1 and the paper discharging device 2. Although it should be represented by a chain line, it is shown here by a solid line for the sake of easy understanding.
[0013]
【The invention's effect】
As described above , according to the image forming apparatus of the present invention, the sheet discharging device that is openably and closably disposed on the sheet discharging side of the fixing device is provided with the cleaning roller that contacts the heating roller or the pressure roller and cleans the roller. since the cleaning roller when opens the sheet discharging device from the fixing device is configured so as to separate from the fixing device, since the cleaning roller is also retracted with discharge device when opening the sheet discharging device, and discharge of the fixing device The space on the paper side is enlarged, and workability when performing maintenance, jam clearance, and the like is improved. In addition, when the paper discharge device is opened, the cleaning roller goes under the guide plate and cannot touch the guide plate, so that not only a large space for jam clearance can be secured, but also a worker is protected from the high-temperature cleaning roller. , Can increase safety.
[Brief description of the drawings]
FIGS. 1A and 1B are explanatory diagrams of a basic configuration and an operation of a fixing device and a sheet discharging device of an image forming apparatus according to the present invention.
FIGS. 2A and 2B are a configuration example and an operation explanatory diagram of a fixing device and a sheet discharging device of the image forming apparatus of the present invention.
FIGS. 3A and 3B are configuration diagrams of an example of an advance / retreat mechanism.
FIGS. 4A and 4B are diagrams illustrating the configuration and operation of a conventional fixing device and sheet discharging device.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 fixing device 2 paper discharge device 3 fulcrum 4 heater 5 heating roller 6 pressure roller 7 cleaning roller 8 paper discharge roller 9 guide plate 10 cleaning roller 15 spring 20 advance / retreat mechanism 21 shaft 22 working piece 23 retreat spring 24 stopper

Claims (1)

A fixing device that includes a heat roller and a pressure roller, receives a transfer sheet holding an unfixed toner image between the two rollers, and fixes and discharges the toner image onto the transfer sheet; and a guide plate and a discharge roller. And a transfer sheet on which the toner image has been fixed, which is ejected from the fixing device in a state in which it is pivotally supported on the discharge side of the fixing device to be openable and closable with respect to the fixing device and is closed with respect to the fixing device. An image forming apparatus comprising: the guide plate; and a paper discharge device that discharges paper to the outside through a paper discharge roller.
The paper ejection device is provided with a cleaning roller that cleans a heating roller or a pressure roller of the fixing device, and an advance / retreat mechanism that advances / retreats the cleaning roller,
The advancing / retracting mechanism is configured such that in a state where the sheet discharging device is closed with respect to the fixing device, the cleaning roller can be cleaned by pressing the cleaning roller against the heating roller or the pressing roller by a first spring, An image forming apparatus configured to retract the cleaning roller by a second spring to a position concealed by the guide plate in a state where the cleaning roller is opened.

Images