KR20080049995A - An image forming apparatus - Google Patents

Abstract

An image forming apparatus is provided to detect the jam of a paper rolled up to a heating roller quickly to stop the operation of the image forming apparatus, thereby preventing the paper jamming from being worse. An image forming apparatus comprises a fixing unit(20) and a jam detecting unit(30). The fixing unit has a heating roller(22) and a press roller(23). The jam detecting unit detects a jammed paper which does not pass through the fixing unit and is rolled up to the heating roller or the press roller. The jam detecting unit comprises a rotary lever(31) and a detecting sensor(33). The rotary lever passes through between the heating roller and the press roller and is installed to be rotated by being pushed by the front end of a paper(P) which is closely attached and rolled up to the heating roller and the press roller while passing through between the heating roller and the press roller. The detecting sensor detects the rotating status of the rotary lever.

Description

An image forming apparatus

1 is a block diagram showing an image forming apparatus according to an embodiment of the present invention.

2 is a view for explaining the fixing unit and the jam generation detection unit shown in FIG.

3 and 4 are views for explaining the operation of the jam generation detection unit.

<Description of Symbols for Major Parts of Drawings>

10. Image forming apparatus main body 11. Paper cassette

12. Developing unit 13. Photosensitive media

14..Intermediate transfer medium 15 .. 1st transfer roller

16..pick-up roller 17 .. 2nd transfer roller

18. Badger 20. Fixing unit

21. Housing 22. Heating roller

23. Pressure roller 30. Jam detection unit

31. Lever lever 33. Sensor

The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus which transfers an image formed in a developing unit to a printing medium and then fixes the transferred image at high temperature and high pressure to form a final image.

In general, an image forming apparatus may be classified into a mono image forming apparatus for forming an image of a black and white color and a color image forming apparatus for forming a color image.

Further, according to the development method, it may be classified into an inkjet image forming apparatus and an electrophotographic image forming apparatus.

In the electrophotographic image forming apparatus, a photosensitive medium such as a photosensitive drum and a photosensitive belt, a laser scanning unit for scanning a laser light onto the photosensitive medium to form an electrostatic latent image corresponding to a desired image, and the electrostatic latent image A developing unit for developing a developer such as toner is provided in the area.

The image formed on the photosensitive medium may be transferred to a print medium through a predetermined transfer medium or directly to a print medium. In the case of a color image, the color image is overlaid on a transfer medium such as an intermediate transfer belt, and then the final color image is transferred onto the print medium. In the case of the mono type image forming apparatus, an image formed on the counseling member can be directly transferred to a print medium.

On the other hand, the print medium on which the image is transferred as described above is fixed at high temperature / high pressure via the fixing unit and then discharged to the outside. Here, the fixing unit typically includes at least one heating roller and a pressure roller, and when a printing medium passes between the heating roller and the pressure roller, a developer such as a toner transferred to the printing medium is transferred to the printing medium by high temperature / high pressure. Sticks.

However, in the process of fixing the print medium at high temperature and high pressure as described above, the print medium is deformed due to the change in surface energy due to the high temperature and high pressure, so-called wrapjams are generated in which the print medium is tightly wound and wound toward the heating roller or the pressure roller. Done.

When the lap jam occurs as described above, there is a problem that the print media is not normally discharged, and the print media printed afterwards also continues to dry.

In view of this, in the related art, a lever that can be rotated on the outlet side of the fixing unit and a jam detection sensor for detecting a rotation state of the lever are installed to check whether or not a lap jam is generated. That is, the time between the pick-up point of the print medium and the discharge point passing through the fixing unit is measured, and if the detection signal is not generated in the jam detection sensor within a predetermined time, it is determined that the lap jam has occurred, and then through a display or the like. Inform the user.

However, according to the above configuration, since the driving of the set, such as the developing unit, the laser scanning unit, the fixing unit, and the like continues until the interval until the operation of the jam detection sensor is detected after the pickup, the user recognizes the jam occurrence When the jam paper is to be removed, since the print media is already curled in a heating roller or the like, it is not easy to remove the jam paper.

In addition, it is not easy for the user to visually check the jam paper rolled up in the fixing unit, so that the image forming apparatus is driven again and picked up again to the next paper, thereby continuing to dry in the fixing unit. As such, when the wrap jam occurs in the fixing unit without falling into the mounting unit, there is a problem in not accurately detecting where exactly the jam occurred.

The present invention has been made to solve the above problems, and an object thereof is to provide an image forming apparatus having an improved structure so as to quickly detect the occurrence of wrap jam in the fixing unit.

An image forming apparatus of the present invention for achieving the above object comprises a fixing unit having a heating roller and a pressure roller; It does not pass through the fixing unit, the jam generation detection unit for detecting the jam paper dried on the heating roller or the pressure roller; characterized in that it comprises a.

Here, the jam generation detection unit, the rotation lever is installed to be rotated by being pushed to the front end of the paper rolled in close contact with the heating roller or the pressure roller while passing between the heating roller and the pressure roller; It is preferable to include a; detection sensor for detecting a rotation state of the rotation lever.

In addition, the rotation lever, the rotation shaft; A first contact lever portion extending from one end of the rotation shaft to contact with the paper curled in the fixing unit; A second contact lever portion extending from the rotation shaft to form a predetermined angle with the first contact lever portion, wherein the tip of the sheet discharged through the fixing unit contacts; And a sensing lever unit extending from the rotating shaft and sensing the rotating state by the sensing sensor.

In addition, the sensing unit, it is good to detect the paper rolled by the heating roller.

Hereinafter, an image forming apparatus according to an exemplary embodiment will be described in detail with reference to the accompanying drawings.

1 is a schematic structural diagram of an image forming apparatus according to an embodiment of the present invention. Referring to FIG. 1, a paper feeding cassette 11 for supplying paper P is provided below the image forming apparatus main body 10. A plurality of developing units 12 are formed inside the main body 10 to form images for each of K, C, M, and Y colors. Each of the developing units 12 uses a potential difference to generate toner particles from a developing roller. It is arranged to receive a constant image on the electrostatic latent image formed on the photosensitive medium (13).

The photosensitive medium 13 may be a drum type or a belt type. An electrostatic latent image corresponding to a desired image is formed on the surface of the photosensitive medium 13 by laser scanning light scanned from a laser scanning unit (not shown).

In addition, an intermediate transfer medium 14 for transferring the color image formed on the photosensitive medium 13 is provided. The intermediate transfer medium 14 is a belt type and is supported by the plurality of support rollers 14a and travels in one direction, and receives the color-specific images formed on the photosensitive medium 13 by superimposition. Reference numeral 15 denotes a primary transfer roller which is installed to correspond to the GAMAM medium 13 with the intermediate transfer medium 14 therebetween.

The color image superimposed on the intermediate transfer medium 14 as described above is secondarily transferred to a printing medium P (hereinafter referred to as printing paper) that is picked up and transported by the pickup roller 16. That is, the printing paper P is transferred between the intermediate transfer medium 14 and the secondary transfer roller 17 which is rotatable in contact, and receives the color image from the intermediate transfer medium 14.

In the main body 10, a fixing unit 20 for fixing the printing paper P, which has been transferred a color image, at a high temperature and a high pressure, and a jam generation detecting unit for detecting a jam occurrence in the fixing unit 20 ( 30).

Referring to FIG. 2, the fixing unit 20 includes a housing 21, a heating roller 22 installed in the housing 21, and a pressure roller 23.

The heating roller 22 is heated to a predetermined temperature by a heater 24 provided inside the heating roller 22. The pressure roller 23 is installed to be in contact with the heating roller 22, the pressure is pushed toward the heating roller 22 by a predetermined pressure member (25). The printing paper P passes through the heating roller 22 and the pressure roller 23.

The jam generation detection unit 30 includes a rotation lever 31 and a detection sensor 33.

The rotation lever 31 includes a rotation shaft 31a, first and second contact lever portions 31b and 31c extending to form a predetermined angle with respect to the rotation shaft 31a, and a detection lever portion 31d. .

As shown in FIG. 3, the first contact lever part 31b does not discharge printing paper P passed between the heating roller 22 and the pressure roller 23 toward the discharge roller 18. It is provided to detect the drying on the roller 22. To this end, the end of the first contact lever portion 31b is disposed close to the heating roller 22, and is rotated in the A direction by being pushed by the tip of the printing paper P wound on the heating roller 22. As shown in FIG. In this way, when the first contact lever portion 31b is rotated in the A direction, the detection lever portion 31d is also rotated in the A direction. Therefore, the detection lever part 31d is out of the detection position of the detection sensor 33, thereby generating an on or off signal from the detection sensor 33. In this way, the on or off signal time point detected by the rotation of the rotation lever 31 in the sensor 33 is calculated from the pick-up time point and compared with the normal time required. Here, the normal time required represents the time taken until the paper is picked up and detected by the second contact lever portion 31c without jamming. Therefore, when the paper is in contact with the first contact lever unit 31b and a signal is generated by the sensor 33, the paper arrives before the normal time required, so that it may be determined that the lap jam has occurred. In this case, it is possible to quickly stop the driving of the set in response to the jam occurrence, and to inform the user of the jam generation signal to keep the jam paper can be removed.

As shown in FIG. 4, the second contact lever part 31c is provided at a position contacting the tip of the printing paper P discharged through the fixing unit 20. The second contact lever portion 31c is rotated in the direction B by being pushed by the tip of the printing paper P, which is normally discharged to the discharge roller 18 side without jamming. Then, the sensing lever part 31d is also rotated in the B direction and moved to the sensing area of the sensing sensor 33 or out of the sensing area. Accordingly, the detection sensor 33 may detect the on / off signal. As such, when the detected time is calculated from the picked-up time and the paper conveying time elapses from the normal time, it can be regarded as jam occurrence.

On the other hand, the detection sensor 33 may be both a contact sensor, a light emitting sensor, a magnetic sensor. This detection sensor 33 is installed within the movement range of one end of the detection lever part 33c. Accordingly, as shown in FIG. 2, the on / off signal is generated whenever the sensing lever part 33c is moved in the A or B direction while being positioned within the sensing range of the sensing sensor 33 to move the paper. It can detect the status and moving position.

On the other hand, the printing paper (P) has been described only for the occurrence of the lap jam is dried on the heating roller 22, but this is merely exemplary. That is, even when the rap jam is formed to be dried on the pressure roller 23, the jam occurrence detection unit 30 can be easily responded by a simple method of changing or adding the position.

As described above, according to the image forming apparatus of the present invention, in detecting the point of time when the printing paper passes through the fixing roller from the time of picking up, the paper not only discharged in the normal direction but also the paper curled in the heating roller The point of view can be detected.

Therefore, it is possible to detect the time of the occurrence of the lap jam to be dried on the heating roller more quickly, and the deterioration of the jam occurrence can be prevented by stopping the driving of the set more quickly than in the prior art. In addition, since jams can be directly confirmed, the user can recognize the jam occurrence and can remove the jam paper wound on the heating roller.

In the above, specific preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and any person having ordinary skill in the art without departing from the spirit and spirit of the present invention claimed in the claims may make various modifications and variations. Would be possible.

Claims (4)

A fixing unit having a heating roller and a pressure roller; And a jam generation detecting unit for detecting a jam paper which does not pass through the fixing unit and which is dried on the heating roller or the pressing roller. According to claim 1, wherein the jam generation detection unit, A rotation lever installed to be rotated by being pushed by the leading end of the paper which is pressed against the heating roller or the pressure roller while passing between the heating roller and the pressure roller; And a sensor for sensing a rotational state of the pivoting lever. The rotating lever of claim 2, A rotating shaft; A first contact lever portion extending from one end of the rotation shaft to contact with the paper curled in the fixing unit; A second contact lever portion extending from the rotation shaft to form a predetermined angle with the first contact lever portion, wherein the tip of the sheet discharged through the fixing unit contacts; And And a sensing lever unit extending from the rotating shaft and sensing the rotating state by the sensing sensor. According to any one of claims 1 to 3, wherein the detection unit, And a sheet of paper curled by the heating roller.

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