JPH08305205A - Fixing device - Google Patents

Abstract

PURPOSE: To provide a fixing device, which can be divided into a fixing unit and an oil application unit so as to simply replace only the fixing unit and reduce the running cost, and has good work efficiency of replacing the fixing unit and the oil application unit, and in which replacement work is safe and oil can be prevented from dripping on paper. CONSTITUTION: A fixing unit 4 of an image forming apparatus 1 comprises a fixing unit 5 having a fixing roller 6 and a pressure roller 7 which is brought into contact with the fixing roller 6, and an oil application unit 10 having an oil application means which is brought into contact with the fixing roller 6 to apply a separating agent to the roller, wherein the fixing unit 5 and the oil application unit 10 can be divided, and the fixing unit 5 or the oil application unit 10 is removably provided on the image forming apparatus main body 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in this type of image forming apparatus, as a replaceable fixing device, (1) a fixing device having a fixing roller 6 and a pressure roller 7 in a horizontal direction as shown in FIG. An oil application unit 10 'having a felt 30 as an oil application means for applying oil as a release agent and an oil tray 32 containing an oil blade 31 is attached and detached from the side below the fixing roller 6 of 4'. What is installed as possible is disclosed in Japanese Patent Laid-Open No. 6-124051 and is publicly known. In such a case, when the fixing roller 6 of the fixing device 4'is replaced, the fixing device 4'is taken out from the main body of the image forming apparatus together with the oil application unit 10 ', and all of them are collectively replaced. . The work of taking out the fixing device 4'from the main body of the image forming apparatus is a. Open the front door, not shown, b. Pull out the fixing device 4 ',
c. Three steps of removing the fixing device 4'from the rail are required. Further, (2) as shown in FIGS.
And a pressure roller 7 that is in pressure contact with the fixing roller 6, and the fixing roller 6 and the pressure roller 7 constitute one unit 34. The image forming apparatus main body 2 was fitted and fitted into the receiving portion 36 of the receiving member 2 ', and the cover 35 provided above the unit 34 was opened to make the unit 34 removable from the receiving member 2'. Those disclosed in Japanese Patent Laid-Open No. 3-81792 are publicly known. An oil-applying felt 30 for applying oil to the fixing roller 6 is located above the fixing roller 6 and attached to the receiving member 2 ′ side. In such a case, oil may drip on the sheet conveyed to the fixing roller 6 to contaminate the sheet, and the fixing roller 6 and the pressure roller 7 may be integrated to expose the fixing roller 6. In this state, it is detached from the image forming apparatus main body 2.

[0003]

In the conventional fixing device as described above, in the case of (1), the oil applying unit having the oil applying member and the oil tray is integrated with the fixing device at the time of maintenance. Since it is provided, when the fixing device is taken out, the fixing unit part having the fixing roller and the pressure roller and the oil application unit part cannot be divided in the image forming device and detached from the image forming device. The workability of removing and replacing the fixing roller with a short life is poor, and all of the above parts must be replaced at once, which increases running costs, and
The operation of attaching / detaching the fixing device to / from the image forming apparatus main body is a.
Open the front door, b. Pull out the fixing device, c.
The workability is poor because the work of three steps of removing the fixing device from the rail is required, and in the case of (2), oil drips on the paper, and during maintenance of the fixing roller, pressure is applied to the fixing roller. When the unit including the roller is taken out from the main body of the image forming apparatus, there is a problem that the fixing roller is exposed and a worker touches the high temperature fixing roller, which is dangerous.

Therefore, an object of the present invention is to solve the problem of the fixing device as described above, and the fixing device can be divided into a fixing unit and an oil applying unit, and only the fixing unit can be easily replaced. The running cost can be reduced, the workability for replacing the fixing unit and the oil application unit is good and safe, and
(EN) It is an object to provide a fixing device in which oil does not drip onto paper.

[0005]

In order to achieve the above-mentioned object, the present invention provides a fixing unit having a fixing roller and a pressure roller abutting against the fixing roller, In a fixing device of an image forming apparatus including an oil applying unit that has an oil applying unit that contacts a fixing roller and applies a release agent, the fixing unit and the oil applying unit are separable, and the fixing unit or the oil is applied. The coating unit is detachably provided on the main body of the image forming apparatus. According to a second aspect of the present invention, in the first aspect of the invention, the fixing unit and the oil applying unit are detachably provided at a lower portion of a main body cover that covers the fixing device of the main body of the image forming apparatus. Therefore, the main body cover is opened and the fixing unit and the oil applying unit are attached and detached. According to a third aspect of the invention, in the first aspect of the invention, an oil application unit is provided below the fixing roller. According to a fourth aspect of the invention, in the first aspect of the invention, the fixing unit is supported by the image forming apparatus main body with the bearing of the rotation shaft of the fixing roller as one end and the bottom surface of the fixing unit as the other end. The motor includes a motor for rotating the fixing roller and a rotation transmitting means for transmitting the rotation of the motor to the fixing roller. The rotation transmitting means allows the rotation moment of the fixing roller to press the fixing unit downward when the motor rotates. It is characterized by being provided in.

[0006]

In the invention as described above, the invention according to claim 1 is such that the fixing unit and the oil applying unit of the fixing device are separable and are detachably attached to the main body of the image forming apparatus. The unit and the oil application unit can be attached to and detached from the main body of the image forming apparatus. According to a second aspect of the present invention, the main body cover that covers the fixing device of the image forming apparatus main body is opened, and the fixing unit and the oil applying unit are attached and detached. According to the third aspect of the invention, the oil applying unit of the oil applying unit provided below the fixing roller contacts the fixing roller to apply the oil. According to the fourth aspect of the present invention, when the motor for rotating the fixing roller rotates, the rotation moment of the fixing roller by the rotation transmitting means pushes the fixing unit downward via the bearing of the rotating shaft.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiments of the present invention shown in FIGS.
The same parts as in the prior art will be denoted by the same reference numerals, and the description thereof will be omitted. The different parts will be mainly described.
In the image forming apparatus 1 shown in FIG. 1, 2 is an image forming apparatus main body, 3 is a main body cover covering the fixing device 4 of the image forming apparatus 1, 5 is a fixing unit of the fixing device 4, and 10 is oil of the fixing device 4. A coating unit, 40 is a writing member, 42 is an intermediate transfer member, 43 to 46 are developing means, 50 is a paper feed cassette, 51 is a paper feed transport path, and 55 is a paper discharge tray.

In FIGS. 2 and 3, the fixing device 4 comprises a fixing unit 5 and an oil applying unit 10, which are provided at a lower part of the main body cover 3 so as to be separable from each other. The fixing unit 5 has a fixing roller 6 having a heater 8 therein, and a pressure roller 7 located above the fixing roller 6 and pressed against the fixing roller 6 and having a heater 8 ′ therein. The lower surface of the fixing roller is housed in the fixing roller main body 5 '.

The oil applying unit 10 is located below the fixing roller 6 and contacts the fixing roller 6 to apply oil which is a release agent, and the oil applying roller 11 contacts the oil applying roller 11 to apply oil. An oil supply roller 12 for applying to the oil application roller 11 and an oil application felt 13 for contacting the oil supply roller 12 and supplying oil to the oil supply roller 12 are provided, and the oil application roller 11 contacts the fixing roller 6. The oil is applied to the main body 10 'of the oil application unit so that the part is exposed. The oil is stored in an oil tank portion 14 that shares the lower portion of the oil application unit 10, and the oil application roller 11 and the oil supply roller 12 are rotatably supported by a support member 15 provided in the oil application unit body 10 '. , One end of the support member 15 is the support shaft 15
The spring 19 is rotatably supported by the oil application unit main body 10 'by a, and the spring 19 is urged to press the bottom surface of the support member 15 to rotate upward.
It is provided between the inside of the bottom surface of 10 ′ and the bottom surface of the support member 15, and this spring 19 allows the oil application roller via the support member 15.
The fixing roller 6 comes into contact with the fixing roller 6 with a predetermined pressing force. However, since the weight of the fixing unit 5 is larger than the upward pressing force of the oil applying roller 11, the fixing unit 5 itself does not float up.

A method of mounting the fixing device 4 at a predetermined position of the fixing member 16 provided on the image forming apparatus main body 2 will be described. The fixing member 16 includes both side wall plates 16a and 16a 'and a bottom surface.
16b and the fixing unit 5 on the side wall plates 16a and 16a '.
And a guide plate 16c for guiding the oil application unit 10 is inserted along the side wall plates 16a, 16a '.
The positioning recess 20 provided on the bottom surface of the oil application unit body 10 'and the positioning first pin 21 provided on the bottom surface 16b of the fixing member 16 are fitted to each other to perform positioning, and the positioning is performed at a predetermined position. Placed.

The fixing roller 6 is provided on both side walls of the fixing unit 5.
A bearing (not shown) that supports the rotating shaft of
When the fixing unit 5 is inserted along the guide plate 16c,
The bearings are fitted into the concave receiving portions 22, 22 'provided on the upper side wall plates 16a, 16a' of the fixing member 16 and are positioned in the front-rear direction in FIGS. 2 and 3 to support the fixing unit 5. , Holes 23 provided in the bottom plate of the fixing unit body 5 '
And the positioning second pin 24 provided on the upper left side of the side wall plate 16a of the fixing member 16 are fitted to each other to be fixed to a predetermined position and fixed. When installed in this way, the fixing unit 5 is positioned above the oil application unit 10, both of which can be divided, and can be attached to and detached from the image forming apparatus main body 2 with accurate position accuracy. Becomes

A mechanism for rotating the fixing roller 6 is provided on the image forming apparatus main body 2 side and has a motor (not shown) for rotating the fixing roller 6 and a rotation transmitting means, and the rotation transmitting means is a rotation shaft of the motor. The gear 26 and the gear 27 attached to the fixing roller 6 share the rotation axis of the fixing roller 6.
A gear 28 attached to one end of the gear 2
6, 27 and 28 are in mesh with each other. When the motor rotates during the fixing operation, the fixing rollers 6 are rotated counterclockwise in FIG. 4 by the gears 26, 27 and 28. Then, when the gear 27 rotates with respect to the gear 28, a moment in the left rotation direction (direction of arrow A in FIG. 4) acts on the fixing roller 6 with the rotation center of the fixing roller 6 as a fulcrum, so that the fixing roller 6 moves. It is arranged at a position where the fixing unit 5 is pressed against the fixing member 16 via the bearing. Therefore, during the fixing operation, the positions of the fixing unit 5 and the fixing roller 6 are fixed and stable, the sheet 53 is stably conveyed, and a good fixing operation can be performed.

When a member such as a rubbing type felt and a blade is used for applying oil to the fixing roller 6, the toner and the paper powder are clogged and fixed to them, causing scratches on the rubber surface and abrasion. In addition, the main chain breaks in the rubber due to the high temperature due to heating to uniformly melt and mix the toners of each color in the color image forming apparatus and the rubber swelling due to the penetration of the release agent (oil), resulting in a decrease in strength. As a result, the life of the fixing roller 6 is shortened. In order to prevent such a situation and maintain a long life, in this embodiment, the fixing roller 6 is made of a material having a high mold release property and a high abrasion resistance, in addition to the fixing roller 6 being selected. 6 is a thick rubber roller, the pressure roller 7 is a thin rubber roller close to a rigid body, and is rotated around the fixing roller 6, and the fixing roller 6 is caused by rubber elastic distortion of the nip portion between the fixing roller 6 and the pressure roller 7. Of toner adhesion to toner (offset)
The effect, that is, the moment when the elastic strain is released at the exit of the nip portion, a displacement occurs at the interface with the toner, and this displacement significantly reduces the adhesive force. That is, as shown in FIG. 4, by curving the nip shape in the direction in which it is recessed toward the fixing roller 6 side, the effect of reducing the toner adhesion force at the exit of the nip portion to the fixing roller 6 side is increased, and offset can be prevented. As other effects, it is possible to prevent uneven gloss and winding jam, and further, (1) the fixing roller 6 and the pressure roller 7 are provided with heaters 8 and 8'incorporated therein to heat the fixing roller 6 and the fixing roller 6, respectively. Is controlled to be lower than the temperature of the pressure roller 7 to prevent the offset by improving the temperature margin against the offset, and (2) to reduce the abrasion of the rubber surface by the contact member to the fixing roller 6. The oil applying roller 11 is used without using a rubbing type oil applying felt as the oil applying means, and the paper 53 cleans the fixing roller 6 for cleaning. We are taking measures such as self-cleaning.

With such a construction, the life of the fixing roller 6 can be maintained for a long time, and at the time of maintenance,
The fixing unit 5 and the oil applying unit 10 are the fixing device 4.
By opening the main body cover 3 that covers the upper part of each of them, each can be easily attached and detached from the image forming apparatus main body 2 in the upward direction without using a special tool, which has good workability and reduces the running cost. The oil applying unit 10 is provided with a first pin for positioning the recess 20 and the fixing member 16 provided on the bottom surface of the oil applying unit body 10 '.
The fixing unit 5 is placed at a predetermined position with the fixing unit 5
Is a bearing provided on both side plates of the fixing unit main body 5'and a concave receiving portion 2 provided on both side wall plates 16a, 16a 'of the fixing member 16.
Fixing unit body 5'as well as fitting to 2, 22 '
23 for positioning the fixing member 16 and the hole 23 provided in the bottom plate of the
24 is fitted and positioned and supported, and further, the fixing unit 5 is pressed and fixed to the fixing member 16 by the rotation moment of the fixing roller 6, so that the fixing unit 5 is installed at the position where the fixing unit 5 is installed in the sheet conveying direction. The accuracy is good, and the oil applying unit 10 is installed below the fixing unit 5 so that the oil does not drip onto the paper 53 during image formation and the paper 53 is not contaminated.

[0015]

The present invention is as described above, and the invention according to claim 1 is such that a fixing unit having a fixing roller and a pressure roller contacting the fixing roller, and a mold releasing by contacting the fixing roller. In a fixing device of an image forming apparatus including an oil applying unit having an oil applying unit for applying an agent, the fixing unit and the oil applying unit are separable, and the fixing unit or the oil applying unit is provided in the main body of the image forming apparatus. Since it is detachably installed, the fixing unit can be easily replaced and the oil can be regularly replenished without using a special tool with good workability. Therefore, there is an effect that it can be exchanged with the new one and the running cost can be reduced. According to a second aspect of the present invention, in the first aspect of the invention, the fixing unit and the oil applying unit are detachably provided at a lower portion of a main body cover that covers the fixing device of the main body of the image forming apparatus. Since the main body cover is opened and the fixing unit and the oil applying unit are attached / detached, the fixing unit can be easily replaced in a one-way take-out step without using a special tool, and workability is good. effective. According to a third aspect of the invention, in the first aspect of the invention, since the oil applying unit is provided below the fixing roller, it is not necessary to separately provide a mechanism for pumping up and supplying oil, and the like. There is an effect that the cost can be reduced, the oil does not drip on the paper, and the paper is not contaminated. The invention according to claim 4 is
In the invention described in claim 1, the fixing unit is supported by the image forming apparatus main body with the bearing of the rotating shaft of the fixing roller as one end and the bottom surface of the fixing unit as the other end, and a motor for rotating the fixing roller, and A rotation transmitting means for transmitting the rotation of the motor, and the rotation transmitting means is provided so that the rotation moment of the fixing roller presses the fixing unit downward when the motor rotates. As a result, the positional accuracy of the fixing device can be maintained, and the fixing device can be stably fixed during operation so that a good fixing operation can be performed.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of an embodiment of the present invention.

FIG. 2 is a schematic vertical cross-sectional view of main parts showing a state in which the fixing device of the above is attached to the main body of the image forming apparatus.

FIG. 3 is a longitudinal cross-sectional view of relevant parts showing a state in which the upper cover is opened upward and the fixing unit and the oil applying unit of the fixing device are taken out upward.

FIG. 4 is a schematic vertical sectional view showing a nip portion between the fixing roller and the pressure roller of the above.

FIG. 5 is a schematic vertical sectional view of a fixing device of a conventional image forming apparatus.

FIG. 6 is a schematic vertical sectional view of a fixing device of another conventional image forming apparatus.

FIG. 7 is a schematic vertical cross-sectional view of essential parts showing a state in which a unit having a fixing roller and a pressure roller of the above fixing device is taken out upward from a receiving member of the image forming apparatus main body.

[Explanation of symbols]

 1 image forming apparatus 2 image forming apparatus main body 3 main body cover 4 fixing device 5 fixing unit 6 fixing roller 7 pressure roller 10 oil application unit 11 oil application roller 12 oil supply roller 13 oil application felt 14 oil tank section 15 support member 16 fixed Member 19 Spring 20 Recess 21 First pin 22 Receiving part 23 Hole 24 Second pin 26, 27, 28 Gear

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsugu Sugiyama 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (4)

[Claims] 1. An image forming apparatus comprising: a fixing unit having a fixing roller and a pressure roller contacting the fixing roller; and an oil applying unit having an oil applying unit contacting the fixing roller to apply a release agent. In the fixing device,
A fixing device, wherein the fixing unit and the oil applying unit are separable, and the fixing unit or the oil applying unit is detachably provided on the main body of the image forming apparatus. 2. A fixing unit and an oil applying unit are detachably provided at a lower part of a main body cover of the main body of the image forming apparatus which covers the fixing device, and the main body cover is opened to apply the fixing unit and the oil applying unit. The fixing device according to claim 1, wherein the unit is attached and detached. 3. The fixing device according to claim 1, wherein an oil application unit is provided below the fixing roller. 4. The fixing unit is supported by the main body of the image forming apparatus with the bearing of the rotating shaft of the fixing roller as one end and the bottom surface of the fixing unit as the other end. The motor rotates the fixing roller and the rotation of the motor. 2. A rotation transmitting means for transmitting to the fixing roller, wherein the rotation transmitting means is provided so that the rotation moment of the fixing roller presses the fixing unit downward when the motor rotates. The fixing device described in 1.