JP2001343846A - Fixing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the contact of a recording medium with a high temperature part due to an operation error by an operator when it is removed in a fixing unit. SOLUTION: In the fixing unit where unfixed toner is melted, heated and fixed onto the recording medium, a recording medium guiding hole by which the recording medium is guided inside the unit and a recording medium guiding hole opening and closing member 24 by which the recording medium guiding hole is energized to a direction to be closed and displaced in the direction opening the recording medium guiding hole against energizing force when loaded into an image forming device main body, are included.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing unit provided in an image forming apparatus for fixing unfixed toner on a recording medium.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
The temperature of the fixing device that melts the unfixed toner and fixes it on the recording medium is high. In view of this, consideration has been made to warn the operator with a warning label at places where a finger may touch the fixing device during jam processing or the like.

[0003] A conventional image forming apparatus will be described below.

In an image forming apparatus, four image forming units are arranged in a line, and each image forming unit has a photosensitive drum on which an electrostatic latent image is formed.

Around the photosensitive drum, a charger for uniformly charging the surface of the photosensitive drum to a predetermined potential, and a developing roller for developing an electrostatic latent image formed on the photosensitive drum are provided. And a first transfer roller for transferring the toner image on the photosensitive drum to the intermediate transfer belt. An exposing device that forms an electrostatic latent image on the photosensitive drum is provided above the image forming unit. A recording medium storage box in which a recording medium is stored is provided below the apparatus.

A second transfer roller for transferring the color image formed on the intermediate transfer belt to the recording medium and a fixing unit for fixing the color image transferred on the recording medium to the recording medium are arranged on the paper transport path. ing.

The fixing unit includes a fixing roller for nipping and conveying the recording medium and a pressure roller. Further, a heat roller is provided, and a fixing belt for fusing and fixing the toner adhered to the recording medium by the heat of the heater transmitted through the heat roller is provided between the fixing roller and the heat roller.

Next, the operation of the image forming apparatus configured as described above will be described.

First, a latent image of a yellow component color of image information is formed on a photosensitive drum. This latent image is visualized as a yellow toner image, and is transferred as a yellow toner image onto the intermediate transfer belt by the first transfer roller.

While the yellow toner image is transferred to the intermediate transfer belt, a magenta component color latent image is formed, and the magenta toner image is visualized. Then, the yellow toner image is superimposed on the intermediate transfer belt on which the transfer of the yellow toner image has been completed.

Hereinafter, image formation is carried out for the cyan toner image and the black toner image in the same manner. When the superposition of the four color toner images on the intermediate transfer belt is completed, the image is formed on the recording medium by the second transfer roller. The color toner images are collectively transferred.

The transferred toner image is heated and fixed on a recording medium by a fixing unit, and a full-color image is formed on the recording medium.

Next, processing when a jam occurs in the fixing unit will be described.

When a jam occurs in which the recording medium wraps around the fixing belt, the fixing unit is removed from the image forming apparatus main body in order to perform the jam processing. Here, when the fixing unit is detached from the image forming apparatus main body, since the fixing unit is held from below, there is a possibility that a finger touches the fixing belt and the pressure roller, which are high temperature parts. Therefore, a warning label is attached to the front of the fixing unit to alert the operator.

[0015]

However, the configuration of the above-described conventional image forming apparatus has the following problems.

When the fixing unit is held from the lower side for jam processing or the like, even if the operator is warned by the warning label, there is a possibility that a finger may erroneously come into contact with the fixing belt and the pressure roller, which are high temperature parts. It is difficult to completely eliminate erroneous operations.

Here, when the recording medium is wound around the pressure roller, the jam processing door is opened to remove the recording medium. At this time, if the recording medium introduction hole is opened, the finger may erroneously touch the fixing belt and the pressure roller, which are the high temperature part. Therefore, it is difficult to completely eliminate erroneous operations even if a warning label is stuck near the jam clearing door to call attention to the operator.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing unit capable of preventing a contact with a high-temperature portion due to an erroneous operation by an operator when removing a recording medium.

[0019]

In order to solve the above problem, a fixing unit according to the present invention is a fixing unit for melting and heating an unfixed toner and fixing the same on a recording medium. The recording medium introduction hole to be introduced into the inside, the recording medium introduction hole is urged in a direction to close the recording medium introduction hole, and in a direction to open the recording medium introduction hole against the urging force when attached to the image forming apparatus main body. And a recording medium introduction hole opening / closing member to be displaced.

With this arrangement, when the fixing unit performs the jam processing, the recording medium introduction hole is closed by the recording medium introduction hole opening / closing member. Can be prevented.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a fixing unit for melting and heating an unfixed toner to fix it on a recording medium, wherein the recording medium is introduced into the unit. A recording medium introduction hole, and a recording medium urged in a direction to close the recording medium introduction hole and displaced in a direction to open the recording medium introduction hole against the urging force when the recording medium is attached to the image forming apparatus main body. This is a fixing unit having an opening / closing member, and when performing a jam processing in the fixing unit, the recording medium introduction hole is closed by the recording medium introducing hole opening / closing member, so that an erroneous operation by an operator when removing the recording medium is performed. This has the effect that it is possible to prevent contact with the high-temperature portion due to

According to a second aspect of the present invention, in the first aspect, the recording medium introduction hole opening / closing member is interlocked with the opening operation of the jam clearance door provided in the image forming apparatus main body. This is a fixing unit that closes the recording medium introduction hole. When performing jam processing in the fixing unit, the recording medium introduction hole is closed by the recording medium introduction hole opening / closing member. This has the effect that it is possible to prevent contact with the high-temperature portion due to

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is a schematic view showing the entire configuration of an image forming apparatus having a fixing unit according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing the fixing unit in the image forming apparatus shown in FIG. FIG. 3 is an explanatory view showing a jam processing when a recording medium is wound around a pressure roller in the image forming apparatus of FIG. 1, and FIG. 4 is a state in which a recording medium introduction hole opening / closing member according to an embodiment of the present invention is opened. Bottom view showing the fixing unit,
FIG. 5 is a bottom view showing the fixing unit according to the embodiment of the present invention with the recording medium introduction hole opening / closing member closed, and FIG. 6 is a perspective view showing the internal configuration of the fixing unit according to the embodiment of the present invention. 7 is a perspective view showing a state in which the fixing unit of FIG. 6 is mounted on the main body of the image forming apparatus. FIG. 8 is a diagram showing a state in which the recording medium introduction hole opening / closing member of the fixing unit of FIG. It is explanatory drawing which shows a state.

As shown in FIG. 1, four image forming units 6y, 6m, 6c and 6k are provided in the image forming apparatus main body 1.
Are arranged in a line at predetermined intervals, and each of the image forming units 6y, 6m, 6c, 6k has a photosensitive drum 3y, 3m, 3c, 3k as an image carrier.

The photosensitive drums 3y, 3m, 3c, 3
k, around each photosensitive drum 3y, 3m, 3c, 3k
Chargers 4y and 4 for uniformly charging the surface of the battery to a predetermined potential
m, 4c, 4k, photosensitive drums 3y, 3m, 3c, 3k
A developing roller 5y for visualizing the electrostatic latent image formed thereon;
5m, 5c, 5k, photosensitive drums 3y, 3m, 3c, 3
First transfer rollers 7y, 7m, 7c, and 7k for transferring the toner image visualized on the intermediate transfer belt 8 to the intermediate transfer belt 8 are arranged. Further, the image forming units 6y, 6m,
Above 6c and 6k, there is provided an exposure unit 2 for irradiating a laser beam corresponding to image information in the main scanning direction of the photosensitive drums 3y, 3m, 3c and 3k to form an electrostatic latent image.

Here, the image forming units 6y, 6m, 6
For c and 6k, a yellow image, a magenta image,
A cyan image and a black image are formed.

Each image forming unit 6y, 6m, 6c, 6
k, the photosensitive drums 3y, 3m, 3c,
Below 3k, there is disposed an endless intermediate transfer belt 8 which is stretched around a driving roller 9 and a driven roller 10 which are rotationally driven by a driving means (not shown) and which rotates in the direction of arrow A.

At the lower part of the apparatus, a recording medium storage box 13 in which a recording medium 14 such as printing paper is stored is provided. Then, the recording medium 14 is sent out from the recording medium storage box 13 to the sheet transport path one by one by a paper feed roller.

The intermediate transfer belt 8 is brought into contact with the outer peripheral surface of the intermediate transfer belt 8 for a predetermined amount on the paper transport path.
A second transfer roller 11 for transferring the color image formed thereon to the recording medium 14, and heating for fixing the color image transferred on the recording medium 14 to the recording medium 14 by the pressure and heat associated with the pinching rotation of the roller Fixing unit 1 with rollers
5 are arranged. The second transfer roller 11 is supported by a jam clearing door 12 which is opened and closed when a paper jam occurs (see FIG. 3).

The fixing unit 15 includes a fixing roller 17 and a fixing roller 17 as shown in detail in FIG.
And a pressure roller 20 for pressing and contacting the recording medium in cooperation with the fixing roller 17.

Further, a heat roller 19 in which a heater 18 is provided is provided, and the fixing roller 17 and the heat roller 19 are connected to the recording medium by heat of the heater 18 transmitted through the heat roller 19. A fixing belt 16 for fusing and fixing the toner adhering to the fixing belt 16 is stretched.

Further, the fixing unit 15 is provided with a cleaning unit 23 for cleaning the fixing belt 16. The cleaning unit 23 includes a cleaning roller 21 that adsorbs toner adhered to the fixing belt 16, and an oil roller 22 that supplies oil to the fixing belt 16 to ensure the releasability of the recording medium 14 and the fixing belt 16. And the fixing unit 1
5 is detachable.

Next, the operation of the image forming apparatus configured as described above will be described.

First, the charger 4y of the image forming unit 6y
The exposure device 2 forms a latent image of yellow component color of image information on the photosensitive drum 3y. This latent image is visualized as a yellow toner image by a developing roller 5y having yellow toner, and is transferred as a yellow toner image onto the intermediate transfer belt 8 by a first transfer roller 7y.

On the other hand, while the yellow toner image is being transferred to the intermediate transfer belt 8, a latent image of the magenta component color is formed in the image forming unit 6m, and then the developing roller 5m
As a result, a magenta toner image by magenta toner is visualized. Then, the magenta toner image is transferred by the first transfer roller 7m of the image forming unit 6m to the intermediate transfer belt 8 on which the transfer of the yellow toner image has been completed in the previous image forming unit 6y, and is superposed on the yellow toner image.

Thereafter, image formation is carried out for the cyan toner image and the black toner image in the same manner, and when the superposition of the four color toner images on the intermediate transfer belt 8 is completed, the recording medium storage box 13 is fed by the feed roller. The recording medium 14 is fed into the nip region by a registration roller (not shown) and adjusted to the printing timing, and toner images of four colors are collectively formed on the recording medium 14 by the second transfer roller 11. Transcribed.

Then, the transferred toner image is heated and fixed on the recording medium 14 by the fixing unit 15, and the recording medium 1
4, a full-color image is formed.

As described above, the plurality of image forming units 6
In the color image forming apparatus having y, 6m, 6c, and 6k, the laser beam emitted from the exposing device 2 exposes the image information on the photosensitive drums 3y, 3m, 3c, and 3k, and a known image forming process is performed. Then, toner images of different colors are sequentially transferred onto the same surface of the intermediate transfer belt 8 conveyed in the direction of arrow B in the drawing. Then, the toner image is collectively transferred to the recording medium 14.

Here, as shown in FIGS. 4 and 5, the fixing unit 15 attached to the image forming apparatus main body 1 by the fixing base 26 has a recording medium introduction hole 29 into which the recording medium 14 is introduced. A recording medium introduction hole opening / closing member 24 that opens and closes is provided. Then, as shown in FIG. 6 and FIG.
An opening / closing lever 25 that runs on 4a to open and close the introduction hole opening / closing member 24 is provided. This open / close lever 25
Urges the recording medium introduction hole opening / closing member 24 in a direction to close the recording medium introduction hole 29 by a spring (not shown).

When the fixing unit 15 is attached to the main body 1 of the image forming apparatus, the main body 1 comes into contact with the opening / closing lever 25 to displace the recording medium introduction hole opening / closing member 24 against the spring force. A contact pin 27 that opens the recording medium introduction hole 29 is provided.

Next, the processing when a jam occurs in the fixing unit 15 will be described.

When a jam such as the recording medium 14 wrapping around the fixing belt 16 occurs, to perform the jam processing,
The fixing unit 15 is detached from the image forming apparatus main body 1.
As a result, the contact pin 27 supported by the image forming apparatus main body 1 and the opening / closing lever 25 are separated from each other, and the recording medium introduction hole opening / closing member 24 is closed. Therefore, even if the fixing unit 15 is held from below, the fixing belt 16 is a high-temperature portion.
In addition, the fixing unit 15 can be removed from the image forming apparatus main body 1 without touching the pressing roller 20 with a finger.

As shown in FIG. 8, the image forming apparatus main body 1 is provided with an opening / closing lever contact pin 28a for contacting the opening / closing lever 25 and a contact portion 28b for contacting the jam processing door 12. A processing door interlocking lever 28 is provided, and the jam processing door interlocking lever 28 rotates in the direction of arrow E in the drawing, that is, when the opening / closing lever contact pin 28a contacts the opening / closing lever 25, the jam clearing operation is performed. Door 1
The rotational torque is applied by a spring (not shown) in the direction in which the motor 2 is closed.

According to this, when the jam processing door 12 is opened to perform the jam processing of the fixing unit 15, the contact portion 12a of the jam processing door 12 and the contact portion 28b of the jam processing door interlocking lever 28 are connected. The jammed door interlocking lever 28 rotates in the direction of arrow E in the drawing, and then the recording medium introduction hole opening / closing member 24 is closed by the opening / closing lever contact pin 28a and the opening / closing lever 25 being separated from each other. Therefore, the work can be performed without touching the fixing belt 16 and the pressure roller 20, which are the high-temperature portions, with the finger during the jam processing.

As described above, according to the present embodiment, the recording medium introduction hole 29 is closed by the recording medium introduction hole opening / closing member 24 when the fixing unit 15 performs the jam processing. Can be prevented from contacting the high-temperature portion due to an erroneous operation by the operator in the case of removing.

[0047]

As described above, according to the present invention, the recording medium introduction hole is closed by the recording medium introduction hole opening / closing member when the fixing unit performs the jam processing. An effective effect is obtained that it is possible to prevent contact with the high-temperature portion due to an erroneous operation by the operator.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an entire configuration of an image forming apparatus having a fixing unit according to an embodiment of the present invention;

FIG. 2 is an explanatory diagram illustrating a fixing unit in the image forming apparatus of FIG. 1;

FIG. 3 is an explanatory diagram showing a jam processing when a recording medium is wound around a pressure roller in the image forming apparatus of FIG. 1;

FIG. 4 is a bottom view showing the fixing unit according to the embodiment of the present invention with a recording medium introduction hole opening / closing member opened;

FIG. 5 is a bottom view showing the fixing unit with the recording medium introduction hole opening / closing member being closed according to the embodiment of the present invention;

FIG. 6 is a perspective view showing the internal configuration of a fixing unit according to an embodiment of the present invention.

FIG. 7 is a perspective view showing a state where the fixing unit of FIG. 6 is mounted on an image forming apparatus main body.

FIG. 8 is an explanatory diagram showing a state in which a recording medium introduction hole opening / closing member of the fixing unit in FIG. 6 operates in conjunction with a jam processing door.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 14 Recording medium 15 Fixing unit 24 Recording medium introduction hole opening / closing member 29 Recording medium introduction hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinichi Tanaka 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Tetsuo Hayama 1006 Kazuma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Keiichi Matsuzaki 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Daimitsu Shimazaki 1006 Odaka Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd.F-term (reference) 2H033 AA37 AA42 BA04 BA37 BA39 BB01 BB28

Claims (2)

[Claims] 1. A fixing unit for melting and heating an unfixed toner and fixing it on a recording medium, comprising: a recording medium introduction hole into which the recording medium is introduced; and a recording medium introduction hole. A recording medium introduction hole opening / closing member that is urged in a closing direction and is displaced in a direction to open the recording medium introduction hole against the urging force when the recording medium introduction hole is attached to the image forming apparatus main body. Fusing unit. 2. The recording medium introduction hole opening and closing member closes the recording medium introduction hole in conjunction with an opening operation of a jam processing door provided in the image forming apparatus main body. The fixing unit as described in the above.