JP2002258650A - Fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fixing device constituted so that the durability of the attaching part of a reflection member is extremely high and capable of realizing the shortening of work time and the reduction of dimensional accuracy. SOLUTION: This fixing device is equipped with a fixing roller 1 equipped with a heating source 5 inside, the reflection member 11 provided on the inner surface of the end of the roller 1 and reflecting heat generated from the heating source 5 to the inner part of the roller 1, and a pressure roller 8 made to abut on the roller 1 with specified pressure. By inserting transfer material to which a toner image is transferred through space between the two rollers, the toner image is heated and melted, and then welded on the transfer material. The roller 1 has a plurality of ribs 4 inside the roller 1 and the member 11 is attached by the ribs 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to a heat fixing device used for an apparatus using an electrophotographic process such as a facsimile and a printer.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a toner image formed on an image bearing member is transferred to a transfer material such as recording paper through a charging, exposing, and developing process, and is then transferred to a transfer material by a fixing device. Is fixed. The fixing device includes a pair of fixing rollers, that is, a fixing roller having a built-in heating source such as a halogen lamp, and a pressure roller rotatably pressed against the fixing roller. With the surface temperature of the heating roller controlled to be constant by controlling the power supply to the heating source, the above-described transfer material is passed between the fixing roller and the pressure roller to heat and pressurize the transfer material. The unfixed toner is fused by heat and fixed.

[0003] In such a fixing device, conventionally, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 308847/1990 discloses a fixing roller provided with a reflection member on the inner surface thereof so as to prevent heat from a heating source from escaping from an end of the fixing roller in order to reduce energy loss. Conventionally, the fixing of the reflection member has been performed by a method such as press-fitting or bonding to the cored bar.

[0004]

However, the load from the pressure roller during paper passing causes the fixing roller to be crushed or bent, and as a result of repeated use, the reflection plate is displaced or dislodged. There was something. Further, in the case of press-fitting, the dimensional accuracy of the outer diameter of the reflection member and the inner diameter of the fixing roller must be strict, which increases the cost of parts. In addition, since the fixing roller is used at a high temperature, it is not possible to fix the reflection member with an adhesive without using, for example, a polyimide-based adhesive. However, polyimide-based adhesives take time to cure, and
It has the disadvantage of being very expensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device and an image forming apparatus in which the durability of a mounting portion of a reflection member is extremely high, and in which a processing time and a dimensional accuracy can be reduced.

[0006]

In order to achieve the above object, the present invention is directed to a fixing roller having a heating source therein, and a heating roller provided on an inner surface of an end portion of the fixing roller. A reflection member that reflects generated heat into the inside of the roller; and a pressure roller that comes into contact with the fixing roller with a predetermined pressure, and a transfer material on which the toner image is transferred is inserted between the two rollers. Thus, in a fixing device that heats and fuses a toner image and fuses the toner image onto a transfer material, the fixing device has a plurality of ribs inside the fixing roller, and the reflection member is attached by the ribs. It is a fixing device. The invention according to claim 2 is the fixing device according to claim 1, wherein a peripheral end surface of the reflecting member is shaped to engage with the rib. According to a third aspect of the present invention, there is provided an image forming apparatus including the fixing device according to the first or second aspect.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a basic configuration of a fixing device according to an embodiment of the present invention. As shown in FIG. 1, the fixing device TS includes a fixing roller 1, a heating source 5 mounted inside the fixing roller 1, a pair of bearings 6 supporting both ends of the fixing roller 1, A drive gear 7 provided on one end side for rotating the fixing roller 1
A rotatable pressure roller 8 that contacts the fixing roller 1 at a predetermined pressure, a temperature sensor 9 such as a thermistor that senses the surface temperature of the fixing roller 1 and controls power supply to the heating source 5,
An excessive temperature rise prevention device 10 is provided at a portion close to the fixing roller 1 (which may be in contact or non-contact).

The fixing roller 1 includes a thin hollow cylindrical core 3 having a plurality of annular ribs 4, in this embodiment, nine ribs 4, formed on an inner surface thereof, and a core 3 formed on the surface of the core 3. And a release layer 2. Further, the fixing roller 1 is provided with a separation claw (not shown) for separating transfer paper.

The release layer 2 is made of PFA (perfluoroalkoxy), PTFE (polytetrafluoroethylene),
There is a mixture of PFA and PTFE and the thickness is 10-30
μm.

The metal core 3 is made of a metallic material, specifically, an aluminum alloy, a copper alloy, iron, stainless steel, or the like. A plurality of ribs 4 are provided on the inner surface, and nine ribs are provided in this embodiment. I have. The thickness of the portion of the core bar 3 without ribs is preferably 1 mm or less, and more preferably 0.6 mm or less, so that the performance is exhibited.

On both inner surfaces of the fixing roller 1, there are provided cylindrical reflecting members 11 for reflecting the heat generated from the heating means. The reflection member 11 is fixed between the two ribs so as not to move in the thrust direction.

As the heating source 5, a halogen lamp, electromagnetic induction heating or the like is used. The pressure roller 8 is
The fixing roller 1 is pressed by a lever and a spring (not shown). The fixing roller 1 is provided with a separation claw for separating transfer paper (not shown). The fixing roller 1 is provided with a temperature sensor 9 such as a thermistor that senses the surface temperature of the fixing roller 1 and controls power supply to the heating source 5.

Further, a portion close to the fixing roller 1 (which may be in contact or non-contact) is provided with an excessive temperature rise prevention device 10 for cutting off the power supply to the heating source 5 when the temperature exceeds a predetermined temperature. Have been. As the excessive temperature rise prevention device 10, a temperature fuse, a thermostat, or the like is used.

According to the fixing device of FIG. 1 configured as described above, the rib 4 is provided on the inner surface of the metal core 3 and the reflecting member 11 is fixed by the rib 4, so that a force is applied to the fixing roller 1. Even if the deformation is repeated in addition, the reflection member 11 can be reliably prevented from shifting or coming off in the thrust direction,
High durability can be obtained.

Another advantage is that the dimensional accuracy of the inner diameters of the reflection member 11 and the fixing roller 1 does not have to be strict as in press fitting. In addition, there is an advantage that an adhesive, which is an expensive material such as bonding, is not required, and the processing time can be reduced.

FIG. 2 is a sectional view showing a basic structure of a fixing device according to another embodiment of the present invention, and FIG. 3 is a sectional view of a reflecting member provided in the fixing device. The fixing device shown in FIG. 2 is different from the fixing device shown in FIG. 1 in that the outer periphery of the reflecting member 11 is formed in a concave groove 11a as shown in FIG. The only difference is that the ribs 4 are fixed so as not to move in the thrust direction by the ribs 4 entering and engaging with the grooves 11a of the reflection member 11, and other configurations are the same as those of the fixing device of FIG. .

According to the fixing device of FIG. 2 configured as described above, in addition to the same effects as those of the fixing device of the embodiment of FIG. 1, the reflecting member 11 can be fixed by one rib 4.
As compared with the fixing device of FIG. 1, the processing time of the rib 4 for attaching the reflection member 11 is half, and the cost can be reduced. That is, since it is not necessary to provide two ribs 4 to fix one reflection member 11, the processing time can be reduced and the cost is advantageous.

FIG. 4 is an explanatory view showing the main configuration of an image forming apparatus provided with a fixing device according to the present invention. As shown in FIG. 4, the image forming apparatus includes a photosensitive drum 21 on which an electrostatic latent image is formed, a charging roller 22 that contacts or approaches the photosensitive drum 21 to perform a charging process, 2
A developing roller 25 for applying toner to the first electrostatic latent image;
Power supply 28 for applying a DC voltage to charging roller 22
A transfer roller 26 for transferring the toner image on the photosensitive drum 21 to the transfer paper P conveyed from the paper supply unit, a cleaning device 27 for removing and collecting residual toner on the surface of the photosensitive drum 21, A fixing device TS having a surface voltmeter 24 for measuring the surface potential of the photosensitive drum 21 and the fixing roller 1 and the pressure roller 8 of the first embodiment of FIG.
And Reference numeral 23 denotes exposure such as laser light or light reflected from a document.

An image forming operation in the image forming apparatus configured as described above will be described. First, a DC voltage is supplied from a power supply 28 to the charging roller 22 that is in contact with the photosensitive drum 21 so that the charging roller 22 contacts the photosensitive drum 21.
Is uniformly charged to a high potential.

Immediately thereafter, when the surface of the photosensitive drum 21 is exposed 23, the exposed portion has a reduced potential. Since the exposure 23 has a light amount distribution corresponding to the density of the image, the exposure 23 forms a potential distribution for the recorded image, that is, an electrostatic latent image on the surface of the photosensitive drum 21.

Next, when the portion where the electrostatic latent image is formed passes through the developing roller 25, toner adheres according to the level of the potential, and a toner image is formed by visualizing the electrostatic latent image. You. Next, the transfer paper P is conveyed at a predetermined timing to a portion where the toner image is formed, and overlaps the toner image. After the toner image is transferred to the transfer paper P by the transfer roller 26, the transfer paper P is separated from the photosensitive drum 21.

Next, the separated transfer paper P is conveyed through a conveyance path, is subjected to heat and pressure fixing by the fixing roller 1 and the pressure roller 8, and is then discharged out of the apparatus. After the transfer, the surface of the photosensitive drum 21 is cleaned by the cleaning device 2.
The cleaning process is carried out by 7 and the residual charges are further erased by a residual charge erasing means (not shown) to prepare for the next image forming process.

At this time, since the fixing roller 1 having a thinned roller core is used as the fixing roller 1,
The temperature rise rate of the fixing roller 1 can be improved, the rise time can be significantly reduced, and power saving can be achieved. That is, both the warm-up time and the lighting time of the halogen heater can be reduced.

Further, since the ribs are made thin and have high rigidity, the rising of the fixing roller is quick, power saving is possible, and an image forming apparatus having stable fixing performance can be obtained.

Further, even if the fixing roller 1 is repeatedly deformed by applying a force, the reflection member 11 can be reliably prevented from shifting or coming off in the thrust direction, and high durability can be obtained. The failure of the image forming apparatus caused by the apparatus can be prevented, and the durability of the image forming apparatus can be improved.

When the fixing device shown in FIG. 2 is used,
As compared with the case where the fixing device of FIG. 1 is used, it is possible to obtain an image forming apparatus with a shorter manufacturing time and lower cost. The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the gist of the present invention.

[0027]

As described above, according to the first aspect of the present invention, since the reflecting member is attached by the rib on the inner surface of the fixing roller, even if the fixing roller is repeatedly deformed due to a force applied thereto, the reflecting member is not reflected. If the member shifts in the thrust direction,
Detachment can be reliably prevented, and high durability can be obtained. In addition, since the reflecting member is attached by the rib, the dimensional accuracy does not have to be strict as in press-fitting. Further, it is not necessary to use an adhesive, which is an expensive material as in bonding, and the processing time can be reduced. There are advantages too. According to the second aspect of the present invention, since the reflecting member can be attached with one rib, the processing time for forming the rib on the fixing roller is shorter than when the reflecting member is attached with two ribs. This is advantageous in terms of cost. According to the third aspect of the present invention, an image forming apparatus having the effects of the first or second aspect can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a basic configuration of a fixing device according to an embodiment of the invention.

FIG. 2 is a cross-sectional view illustrating a basic configuration of a fixing device according to another embodiment of the present invention.

FIG. 3 is a sectional view of a reflection member provided in the fixing device of FIG. 2;

FIG. 4 is an explanatory diagram illustrating a main configuration of an image forming apparatus including a fixing device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Release layer 4 Rib 5 Heat source 8 Pressure roller 9 Temperature sensor 10 Overheat prevention device 11 Reflection member 11a Groove

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Eiji Sawamura, Inventor 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Atsushi Ishibe 1-3-6, Nakamagome, Ota-ku, Tokyo Stock F-term in Ricoh Company (reference) 2H033 AA23 AA31 BA26 BB12 BB17 3J103 AA02 AA13 BA03 CA52 GA02 GA66 HA03 HA04 HA15 HA33 HA36 HA37 HA41 3K058 AA45 BA18 DA02

Claims (3)

[Claims] 1. A fixing roller having a heating source therein, a reflection member provided on an inner surface of an end portion of the fixing roller for reflecting heat generated from the heating source inside the roller, And a pressure roller which is brought into contact with a predetermined pressure, and a transfer material on which the toner image has been transferred is inserted between these two rollers, whereby the toner image is heated and melted and fused on the transfer material. A fixing device, comprising: a plurality of ribs inside the fixing roller; and the reflection member is attached by the ribs. 2. The fixing device according to claim 1, wherein a peripheral end surface of the reflection member is shaped to engage with the rib. 3. An image forming apparatus comprising the fixing device according to claim 1.