JPH04336581A - Fixing device - Google Patents

Abstract

PURPOSE:To enable anybody to uniformly set a gap between a fixing roller and a temperature detection element with a very simple operation. CONSTITUTION:A temperature detection element 12 is caused to lightly contact the non-sheet feed section 1B of a fixing roller 1 with setscrews 10 loosened, and then the setscrews 10 are tightened to fix a bracket 7 to a travel body 6. When the bracket 7 is shifted to the sheet feed section 1A of the fixing roller 1 via the travel body 6, the temperature detection element 12 in light contact with the non-sheet feed section 1B of the fixing roller 1 can maintain a constant gap L from the surface thereof.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention involves sandwiching and conveying a transfer material carrying an unfixed toner image between a heated fixing roller and a pressure roller that is in pressure contact with the fixing roller. The present invention relates to a fixing device that fixes the image on a transfer material.

0002

2. Description of the Related Art Fixing devices of the above type are well known and are attached to copiers, printers, facsimile machines, and the like. In this type of fixing device, a temperature sensing element is used to detect the surface temperature of the fixing roller, and the heating means is controlled so that the fixing roller maintains a predetermined temperature. In this case, there are two types of temperature sensing elements: one in which the temperature sensing element is in contact with the surface of the fixing roller, and the other in a non-contact manner.
Each contactless method has its advantages and disadvantages. The advantages of the non-contact method are that the fixing roller is not damaged, the temperature sensing element is not damaged, and the fixing roller and temperature sensing element have a long lifespan. However, as shown in the graph of FIG. 7, the non-contact method has a problem in that as the distance between the fixing roller and the temperature sensing element increases, the temperature difference between the fixing roller and the temperature sensing element increases, making it difficult to accurately detect the temperature.

[0003] In order to solve this problem, the temperature sensing element must be installed so that the distance from the fixing roller is extremely small. However, if the temperature sensing element is placed too close to the fixing roller and comes into contact with it, not only will the advantage of the non-contact method be lost, but also the temperature sensing device, which generally uses thinner substrates and brackets in order to improve temperature tracking. This could result in fatal injuries. Conventionally, the temperature sensing element 22 was supported by a bracket 21, and the distance between the fixing roller 20 and the temperature sensing element 22 was adjusted using a clearance gauge 23, as shown in FIG.

0004

However, when the above-described clearance gauge 23 is used, since the fixing roller 20 has a curved surface, the adjusted clearance will vary as shown in FIG. Furthermore, since the feeler gauge 23 is generally made of metal, there is a risk of damaging the surface of the fixing roller 20 when it comes into contact with it, which poses a problem in that the work is time-consuming. It is also possible to set a minute gap using only the accuracy of the parts without using the feeler gauge 23, but even a simple configuration uses 3 or 4 parts, and the tolerances of these parts can be accumulated. However, there was a problem in that the tolerance became larger than the desired gap.

The present invention solves the above-mentioned conventional problems, and
It is an object of the present invention to provide a fixing device that allows anyone to uniformly set the distance between a fixing roller and a temperature detection element with extremely simple work.

[0006]

[Means for Solving the Problems] The structure of the present invention that achieves the above object is as follows. (1) A transfer material carrying an unfixed toner image is sandwiched and conveyed by a heated fixing roller and a pressure roller that is pressed against the fixing roller, and at this time, the unfixed toner image is fixed to the transfer material. In the fixing device, the temperature detecting means is disposed close to the surface of the fixing roller and detects the surface temperature of the fixing roller; a moving means that moves parallel to the axis of the fixing roller between a detection position for detecting the paper passing area and a retracted position of the non-paper passing part of the fixing roller, and the non-paper passing part of the fixing roller has a larger diameter than the paper passing part. 2. A fixing device, characterized in that the temperature detecting means is adjusted and fixed to the moving means in a state in which the temperature detecting means is in contact with a non-sheet passing portion of the fixing roller at a retracted position.

(2) The moving means includes an axis parallel to the axis of the fixing roller, a moving body movable on the axis, and the moving body capable of adjustment movement in a direction toward and away from the fixing roller, and The fixing device according to (1) above, further comprising a bracket that supports the temperature detection means.

(3) A heated fixing roller and a pressure roller pressed against the fixing roller nip and convey the transfer material carrying the unfixed toner image, and at this time, the unfixed toner image is fixed on the transfer material. In the fixing device, the temperature detection means is disposed close to the surface of the fixing roller and detects the surface temperature of the fixing roller, and the temperature detection means is supported;
and a moving means for moving the temperature detection means parallel to the axis of the fixing roller between a detection position for detecting the surface temperature of the paper passing portion of the fixing roller and a retracted position of the non-paper passing portion of the fixing roller; A fixing device characterized in that a cleaning member that contacts the temperature detecting means is provided in a non-sheet passing portion of the fixing roller.

(4) A transfer material carrying an unfixed toner image is conveyed by a heated fixing roller and a pressure roller that is pressed against the fixing roller, and at this time, the unfixed toner image is fixed on the transfer material. In the fixing device, the temperature detection means is disposed close to the surface of the fixing roller and detects the surface temperature of the fixing roller, and the temperature detection means is supported;
and a moving means for moving the temperature detection means parallel to the axis of the fixing roller between a detection position for detecting the surface temperature of the paper passing portion of the fixing roller and a retracted position of the non-paper passing portion of the fixing roller; Paper non-passing portions are provided on both sides of the fixing roller, one non-paper passing portion is formed to have a larger diameter than the paper passing portion, and the temperature sensing means is in contact with the paper non-passing portion of the fixing roller at the retracted position. A fixing device, wherein the fixing device is adjusted and fixed to the moving means, and the other non-sheet passing portion is provided with a cleaning member that comes into contact with the temperature detecting means.

0010

[Operation] According to the configuration (1) above, the non-paper passing portion of the fixing roller is formed to have a larger diameter than the paper passing portion, and the temperature sensing means is brought into contact with the non-paper passing portion of the fixing roller at the retracted position. Since the fixing roller can be adjusted and fixed to the moving means in the same state, the distance between the fixing roller and the temperature detecting means can be easily set based on the difference in diameter between the non-sheet passing portion and the sheet passing portion of the fixing roller.

According to the configuration (3) above, since the cleaning member that comes into contact with the temperature detection means is provided in the non-paper passing portion of the fixing roller, simply moving the temperature detection means to the non-paper passing portion allows Can be kept clean.

According to the configuration (4) above, one of the non-paper passing portions of the fixing roller is formed to have a larger diameter than the paper passing portion, and the temperature sensing means is brought into contact with the non-paper passing portion of the fixing roller at the retracted position. The other paper non-passing section is provided with a cleaning member that comes into contact with the temperature detection means, so that the diameter of the fixing roller's non-paper passing section and paper passing section can be adjusted. A difference can be set as the distance between the fixing roller and the temperature sensing means, and the temperature sensing means can be kept clean.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory diagram of a fixing device according to the present invention. In FIG. 1, reference numeral 1 denotes a fixing roller, and the fixing roller 1 is rotatably mounted on a side plate 4 via a heat insulating bush 2 and a bearing 3. A pressure roller (not shown) is pressed against the fixing roller 1, and a heater (not shown) as a heating means is built-in. The surface of the fixing roller 1 consists of a paper passing section 1A through which the transfer material passes, and a non-paper passing section 1B at the side edge, and the non-paper passing section 1B is formed to have a slightly larger diameter than the paper passing section 1A. There is. The difference in diameter between the paper non-passing section 1B and the paper passing section 1A becomes a gap between the fixing roller 1 and a temperature sensing element 12, which will be described later.

Near the fixing roller 1, a screw shaft 5 whose axis is parallel to the axis of the fixing roller 1 is rotatably supported by a side plate 4. A movable body 6 is screwed onto the screw shaft 5, and a bracket 7 is fixed to the movable body 6 with a screw 10. The screw shaft 5 is driven and connected to a reversible motor (not shown), and as the screw shaft 5 rotates, the bracket 7 is reciprocated in parallel with the axis of the fixing roller 1 via the movable body 6. Ru.

As shown in FIG. 2, the bracket 7 has the following features:
It consists of a mounting part 8 and a box-shaped support part 9. Two parallel long holes 8a extending perpendicularly to the axis of the fixing roller 1 are formed in the mounting part 8, and a screw 1 is inserted through the long holes 8a.
0, the bracket 7 is fixed to the movable body 6. A substrate 11 on which a temperature sensing element 12 as a temperature sensing means is mounted is fixed to the lower part of the support portion 9 with screws or the like. Further, a hole 9a is formed in the support portion 9 of the bracket 7, and by providing this hole 9a, the temperature sensing element 1
2 has improved temperature followability. The screw shaft 5, the moving body 6, and the bracket 7 constitute the moving means of this embodiment. Further, reference numeral 13 is a terminal of the temperature sensing element 12, and when the bracket 7 moves toward the center of the fixing roller 1, the terminal 13 is connected to a connector 14 provided approximately at the center of the fixing roller 1.

In the fixing device configured as above, the temperature sensing element 12 is attached to the non-sheet passing portion 1B of the fixing roller 1 with the screw 10 loosened.
make light contact with each other and tighten the screw 10 to fix the bracket 7 to the movable body 6. Then, when the screw shaft 5 is rotated to move the bracket 7 toward the sheet passing portion 1A of the fixing roller 1, the terminal 13 of the temperature sensing element 12 is connected to the connector 14. At this time, when the temperature sensing element 12 that has lightly touched the non-paper passing section 1B of the fixing roller 1 moves toward the paper passing section 1A,
A constant gap ΔL is obtained with respect to the surface of the fixing roller 1.

[0017] In this way, the temperature sensing element 12 can be easily detected by a simple operation.
The gap between the fixing roller 1 and the fixing roller 1 can be set, and a constant gap ΔL can always be obtained no matter who performs the fixing. Note that the gap ΔL is one half of the difference in diameter between the non-sheet passing portion 1B and the sheet passing portion 1A of the fixing roller 1, and the diameters of the non-sheet passing portion 1B and the sheet passing portion 1A are determined as appropriate. You can set the desired spacing.

Incidentally, the smaller the gap ΔL is, the more advantageous it is because there is no difference between the surface of the fixing roller 1 and the detected temperature. However, if the gap ΔL is small, dirt such as toner on the fixing roller 1 will easily adhere to the temperature sensing element 12, and if the temperature sensing element 12 becomes dirty, the detection accuracy will decrease.

In order to solve this problem, the present invention takes the following measures. In FIG. 3, the surface of the fixing roller 1 consists of a paper passing section 1A through which the transfer material passes, and a non-paper passing section 1B at the side edge, and a temperature sensing element 12 is installed in the non-paper passing section 1B. A brush 15 is provided as a cleaning member. Note that the cleaning member is not limited to the brush 15, but may also be felt or the like. Further, as in the above embodiment, the temperature sensing element 12 is supported by a bracket 7 attached via a moving body 6 to a screw shaft 5 whose axis is parallel to the axis of the fixing roller 1, as shown in FIG. . The bracket 7 is made up of an attachment part 8 and a box-shaped support part 9, and the attachment part 8 is formed with two parallel long holes 8a extending perpendicularly to the axis of the fixing roller 1. The bracket 7 is fixed to the movable body 6 with screws 10 via.

The fixing device configured as described above has a temperature sensing element 12 attached to the non-sheet passing portion 1B of the fixing roller 1 with the screw 10 loosened.
If the bracket 7 is adjusted and moved along two vertically extending parallel long holes 8a and the bracket 7 is fixed to the movable body 6 by tightening the screw 10, an appropriate spacing L1, L2 shown in FIG. 6 can be obtained. Then, when the screw shaft 5 is rotated and the bracket 7 is moved between the paper passing section 1A and the non-paper passing section 1B of the fixing roller 1, the temperature sensing element 12 comes into contact with the brush 15 in the non-paper passing section 1B. Cleaned. Note that when the temperature sensing element 12 is located in the non-sheet passing portion 1B, copying is not performed during warming up or the like.

[0021] Thus, even if the temperature sensing element 12 becomes dirty,
Since the brush 15 is used for cleaning, it is possible to prevent the detection accuracy of the temperature detection element 12 from decreasing.

Further, in the present invention, the surface of the fixing roller 1 is composed of a sheet passing portion 1A through which the transfer material is passed, and two non-sheet passing portions 1B on both sides of the sheet passing portion 1A, one of which is non-sheet passing. The section 1B is formed to have a slightly larger diameter than the paper passing section 1A, and a brush 1 as a cleaning member for cleaning the temperature sensing element 12 is provided in one non-paper passing section 1B.
5 may be provided. By supporting the temperature sensing element 12 on the bracket 7 attached via the movable body 6 to the screw shaft 5 whose axis is parallel to the axis of the fixing roller 1, the temperature can be detected easily. Element 12
It is possible to set the gap between
Even if it gets dirty, it can be cleaned with the brush 15. At this time, the temperature sensing element 12 is connected by reel type wiring.

[0023]

According to the above structure, the non-paper passing portion of the fixing roller of the present invention is formed to have a larger diameter than the paper passing portion, and the temperature detection means is connected to the non-paper passing portion of the fixing roller at the retracted position. Since the fixing roller can be adjusted and fixed to the moving means while in contact with each other, the difference in diameter between the non-sheet passing portion and the sheet passing portion of the fixing roller can be set as the distance between the fixing roller and the temperature sensing means. Furthermore, since the cleaning member that contacts the temperature detection means is provided in the non-paper passing portion of the fixing roller, it is possible to keep the temperature detection means free of dirt by simply moving the temperature detection means to the non-paper passing portion.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a fixing device according to the present invention.

FIG. 2 is a perspective view of the bracket.

FIG. 3 is an explanatory diagram showing another embodiment of the present invention.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is an explanatory diagram of a fixing device according to the present invention.

FIG. 6 is a perspective view of the bracket.

FIG. 7 is a diagram showing the relationship between the distance between the fixing roller and the temperature sensing element and the temperature difference between the fixing roller and the temperature sensing element.

FIG. 8 is an explanatory diagram showing a conventional distance setting between a fixing roller and a temperature sensing element.

FIG. 9 is an explanatory diagram showing the problem in FIG. 8;

[Explanation of symbols]

1 Fixing roller 5 Screw shaft 6. Mobile object 7 Bracket 11 Board 12 Temperature sensing element 15 Brush

Claims (4)

[Claims] Claim 1: A transfer material carrying an unfixed toner image is sandwiched and conveyed by a heated fixing roller and a pressure roller that is pressed against the fixing roller, and at this time, the unfixed toner image is fixed to the transfer material. In the fixing device, the temperature detecting means is disposed close to the surface of the fixing roller and detects the surface temperature of the fixing roller; It has a moving means that moves parallel to the axis of the fixing roller between a detection position for detecting surface temperature and a retracted position of the non-paper passing section of the fixing roller, and the non-paper passing section of the fixing roller is moved from the paper passing section. A fixing device having a large diameter, the temperature detecting device being adjusted and fixed to the moving device in a state in which the temperature detecting device is in contact with a non-sheet passing portion of the fixing roller at a retracted position. 2. The moving means includes an axis parallel to the axis of the fixing roller, a moving body movable on the axis, and the moving body adjustable in a direction toward and away from the surface of the fixing roller. The fixing device according to claim 1, further comprising a bracket that supports the temperature detection means. 3. A heated fixing roller and a pressure roller that is pressed against the fixing roller nip and convey a transfer material carrying an unfixed toner image, and at this time, the unfixed toner image is fixed to the transfer material. In the fixing device, the temperature detecting means is disposed close to the surface of the fixing roller and detects the surface temperature of the fixing roller; a moving means that moves parallel to the axis of the fixing roller between a detection position for detecting surface temperature and a retracted position of a non-sheet passing portion of the fixing roller; A fixing device comprising a cleaning member that comes into contact with the fixing device. 4. A transfer material carrying an unfixed toner image is nipped and conveyed by a heated fixing roller and a pressure roller that is pressed against the fixing roller, and at this time, the unfixed toner image is fixed to the transfer material. In the fixing device, the temperature detecting means is disposed close to the surface of the fixing roller and detects the surface temperature of the fixing roller; a moving means that moves parallel to the axis of the fixing roller between a detection position for detecting surface temperature and a retracted position of a non-paper passing portion of the fixing roller, and the non-paper passing portions are provided on both sides of the fixing roller; One non-paper passing section is formed to have a larger diameter than the paper passing section, and is adjusted and fixed to the moving means with the temperature sensing means in contact with the non-paper passing section of the fixing roller at the retracted position. A fixing device characterized in that a cleaning member that contacts the temperature detection means is provided in the paper non-passage section.