JPH10149047A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized oil-feeding mechanism excellent in oil feeding performance by providing an oil feeding felt formed of a plurality of layers for supplying oil from an oil basin to an oil application part, and forming the contact side with a heat roller of the oil feeding felt of a highly heat resisting oil applying felt, and the other layer of an oil absorbing felt having high oil impregnating property. SOLUTION: An oil feeding felt 911 for supplying oil to a heat roller 901 for heating a toner image side surface is formed of a composite of an oil applying felt 911a which makes contact with the circumferential surface of the heat roller 901 to apply oil thereto and an oil absorbing felt 911b which is pressed onto the back surface of the oil applying felt 911a to supply the oil thereto. The oil feeding felt 911 is screwed to and supported by a felt guide 912. Thus, a sufficient quantity of oil can be supplied to the heating roller 901 by the impregnating property of the oil feed felt 911 without using an oil pump mechanism for oil feed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fixing device for fusing a toner image to a recording medium (recording paper) in an electrophotographic apparatus.

[0002]

2. Description of the Related Art An electrophotographic apparatus such as an electrophotographic copying machine or an electrophotographic printer forms a toner image on a toner receptor such as a photosensitive drum or an intermediate transfer drum, and supplies the toner image from a recording paper cassette. After the image is transferred onto the recording paper to be printed, the operation of welding and fixing the toner to the recording paper by the heat fixing roller in the fixing device is repeated.

FIG. 2 shows such a general electrophotographic color printer. This color printer includes a photosensitive belt 1 and yellow, magenta, cyan (three primary colors) and black 4 for developing a toner image by developing an electrostatic latent image formed on the surface of the photosensitive belt 1. Developing units 2Y, 2M, 2C and 2K for the colors, an intermediate transfer drum 3 for forming a color toner image by repeatedly transferring and polymerizing the toner images of each color formed on the photosensitive belt 1, and a paper cassette 4; And a paper feed roller 6 for extracting the recording paper 5 from the intermediate transfer drum 3 when the recording paper 5 arrives on the intermediate transfer drum 3 so as to press the recording paper 5 onto the intermediate transfer drum 3. A transfer roller 7 for re-transferring the color toner image to the recording paper 5, a charge eliminator 8 for removing electricity from the back surface of the recording paper 5 to assist the separation from the intermediate transfer drum 3, and a color toner transferred to the recording paper 5 Fusing the image to the recording paper 5 Comprising a fixing device 9 for fixing.

As shown in FIG. 3, the fixing device 9 includes a heating roller 901 for heating the side of the toner image on the recording paper 5,
A heating roller 902 for heating the anti-toner image side surface is provided.
These heating rollers 901 and 902 are heated by heater lamps 903 and 904 inserted at their centers. Further, a cleaning roller 905 and an oil supply felt 9 are provided around the outer periphery of the heating roller 901 for heating the side surface of the toner image.
06, Oil blade 907 for scraping excess oil
Are provided so as to contact the outer peripheral surface.

[0005] The lower end of the refueling felt 906 is suspended in an oil pan 908 and is immersed in silicone oil 909 filled in the oil pan 908. The silicon oil 30 in the oil pan 908 is supplied from the oil bottle 910 by the consumed amount. Heating roller 90
The silicon oil excessively supplied to 1 and scraped off by the oil blade 907 returns to the oil pan 909.

A fixing device used in a color electrophotographic apparatus needs to sufficiently melt the toner in order to increase the color developability of the color. Further, the object to be printed is not a character but a blackening (coloring) rate. In some cases, the toner melted on the recording paper 5 easily transfers from the recording paper 5 to the heating roller 901, and the toner transferred to the heating roller 901 re-transfers to the recording paper. To make the image dirty.

In order to prevent such a phenomenon, as described above, silicone oil is applied onto the heating roller 901 on the toner image side, so that the releasability of the surface of the heating roller 901 is increased, and In this case, a measure is taken to prevent the toner melted in the step from transferring onto the heating roller 901.
In order to prevent the silicone oil applied to the heating roller 901 from being repelled by the material having good releasability on the surface layer of the heating roller 901, a silicone rubber having a good affinity for the silicone oil is used for the surface layer of the heating roller 901. Must.

However, since silicon rubber easily absorbs silicon oil, a sufficient amount of oil is generally supplied to the surface of the heating roller 901 to apply a predetermined amount of silicon oil over the entire width of the surface of the heating roller 901. ,
A method is adopted in which excess silicon oil on the heating roller 901 is scraped off by an oil blade 907.

In order to supply a sufficient amount of oil onto the heating roller 901, generally, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Application Publication No. 8 (Kokai) No. 8, an oil suction pump is provided, or a heat-resistant roll paper impregnated with oil is brought into contact with a heating roller.

[0010]

In the conventional oil supply system, a mechanism such as an oil pump is required, so that the structure around the heating roller is complicated and large.

Since the early color electrophotographic apparatus was configured as a color copying machine, the size of the apparatus was determined by the size of the image scanner unit, and enlargement of the apparatus due to the oil supply unit was a serious problem. However, in a color electrophotographic apparatus dedicated to a printer, an increase in size of the apparatus due to the oil supply unit has become a major problem.

Further, the oil supply system using the lubricating felt can reduce the size of the apparatus. However, since the lubricating felt made of a heat-resistant material must be used, there is a problem in the lubricating performance. For printers,
There was a problem of poor refueling.

An object of the present invention is to provide a small oil supply mechanism having excellent oil supply performance.

[0014]

According to the present invention, there is provided a heating roller for heating a toner image transferred onto a recording sheet and fusing it to the recording sheet, and oil supply means for applying oil to the outer peripheral surface of the heating roller. In the fixing device, the oil supply means is provided with a plurality of layers of composite felt for supplying oil from an oil reservoir to an oil application section. The composite felt has a heat-resistant felt layer on the side in contact with the heating roller and a felt layer having a high oil-impregnating property on the other layer, thereby satisfying the heat resistance and the lubricating property.

[0015]

FIG. 1 is a vertical sectional side view of a fixing device in an electrophotographic color printer according to the present invention. Components equivalent to those of the conventional color printer described with reference to FIGS. 2 and 3 are denoted by the same reference numerals, and redundant description will be omitted, or description will be omitted.

A heating roller 901 for heating the toner image side surface of the recording paper 5 and a heating roller 90 for heating the anti-toner image side surface
2 has a surface layer made of silicone rubber. Heater lamps 903 and 904 inserted in the center of both heating rollers 901 and 902 heat the surface layers of both heating rollers 901 and 902 to approximately 140 ° C.

Heating roller 901 for heating the side of the toner image
The oil supply felt 911 that supplies oil to the heating roller 901 is a composite of an oil application felt 911a that contacts the outer peripheral surface of the heating roller 901 to apply oil, and an oil suction felt 911b that is pressed against the back surface of the oil application felt 911a and supplies oil. And is supported by screwing (or caulking) to the felt guide 912. The lower end of the oil sucking felt 911b is suspended in an oil pan 908, and is immersed in silicone oil 909 filled in the oil pan 908.

As the fueling felt 911, generally,
The heat-resistant felt is made of a heat-resistant artificial fiber such as a heat-resistant nylon fiber (aramid fiber). However, there is little room for selection of physical properties such as density due to the specialty of the material, and because of the artificial fiber, the surface of the fiber has few irregularities and relatively little capillary action. For the purpose of oil impregnation, it is difficult to obtain those having the best physical properties.

However, if felt is selected irrespective of heat resistance, it is possible to obtain a wide range of physical properties.

FIG. 4 shows the results of experiments on the oil suction capacity of various materials with respect to the time of felt. The suction capacity is compared with the time for sucking oil up to a certain height. It can be seen that there is a difference in the oil sucking ability with respect to time depending on the material and the density. Density 0.3g /
There is a peak of the oil sucking capacity near cm ^3, and the necessary sucking capacity required to maintain the releasability of a general silicone rubber heating roller is 0.15 to 0.
Felt with density of 425g / cm ³ satisfies the suction volume,
Further, it can be seen that the felt made of wool is superior to the felt made of heat-resistant nylon.

In this embodiment, the oil-coated felt 911a is made of a heat-resistant nylon felt (thickness: 3 m).
m, density: about 0.2 g / cm ³ ), and wool felt (thickness: 2 m) is used for the oil sucking felt 911b.
m, density: about 0.35 g / cm ³ ), and silicone oil 909 having a viscosity of 100 CS was used.

In this embodiment, since the oil sucking felt 911b is a felt using wool fiber which is animal hair, it has many fine projections on the fiber surface and strong capillary action. Is the most common material, so a wide range of densities can be obtained. Therefore, it is possible to easily select an object with the optimum density for oil suction, to secure a sufficient oil suction amount, and to stably supply a sufficient amount of oil without equipping an oil pump mechanism. Can be

Further, since the oil-coated felt 911a in contact with the heating roller 901 has heat resistance of 150 ° C. or more, it does not deteriorate due to the heat received from the heating roller 901 and the oil suction felt 911 on the back surface thereof.
A sufficient amount of oil received from the heating roller 9
01 can be applied to the surface.

The oil sucking felt 911b is
Polyester fiber felt (thickness: 2 mm, density: approximately 0.3 g / cm ³ ) can be used. Although the oil absorption capacity is slightly inferior to wool, it is often used as a packing material and is not a special material like heat-resistant nylon, so it is possible to obtain a relatively wide variety of densities. This is advantageous for a fixing device used in a high-speed color printer in which the set temperature of the heating roller 901 needs to be set higher because the heat resistance temperature is higher than that of the fixing device.

These oil sucking felts 911b
Is approximately 0.15 to 0.425 g / cm ³ from the viewpoint of impregnation.
The material density is desirably as described above.

The illustrated and described embodiment employs a refueling felt 9.
Although a two-layer composite is exemplified as 11, the number of layers can be further increased. In addition, oil-coated felt 911a
Is 1 for the heating roller 901 having a relatively low temperature.
Any material having a heat resistance of at least 00 ° C. can be put to practical use.

The fueling felt 911 is assembled into the apparatus while being bent or bent into a desired shape. However, since the oiling felt 911 composed of a plurality of layers is easy to bend, the assembling workability is improved. Can be.

[0028]

As described above, according to the present invention, a sufficient amount of oil can be supplied to the heating roller by the impregnation of the oil supply felt without using an oil pump mechanism for oil supply. It is possible to obtain an oil supply mechanism excellent in lubrication.

In addition, by making the refueling felt a composite of a plurality of layers, the assembling workability can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a fixing device in an electrophotographic color printer according to the present invention.

FIG. 2 is a vertical side view of a conventional electrophotographic color printer.

FIG. 3 is a vertical sectional side view of a fixing device in a conventional electrophotographic color printer.

FIG. 4 is a characteristic diagram of oil suction by a felt;

[Explanation of symbols]

901, a heating roller on the toner image side; 902, a heating roller on the anti-toner image side; 908, an oil pan; 909, silicone oil; 911, an oil supply felt; 911a, an oil application felt;
…silicon oil.

Claims (7)

[Claims] 1. A fixing device comprising: a heating roller for heating a toner image transferred to a recording sheet to fuse the toner image onto the recording sheet; and an oil supply unit for applying oil to an outer peripheral surface of the heating roller. The fixing device includes a composite felt having a plurality of layers for supplying oil from an oil reservoir to an oil application unit. 2. The fixing device according to claim 1, wherein the heating roller has a surface layer made of silicone rubber. 3. The composite felt according to claim 1, wherein:
A fixing device, wherein a side in contact with the heating roller is a heat-resistant felt layer of 100 ° C. or higher. 4. The composite felt according to claim 1, wherein:
A fixing device, wherein a side in contact with the heating roller is a heat-resistant felt layer having a temperature of 150 ° C. or higher. 5. The composite felt according to claim 1, wherein:
A fixing device comprising a felt layer having a large oil impregnating property. 6. The felt layer according to claim 5, wherein the felt layer having a high oil impregnation property has a material density of about 0.15 to 0.425.
g / cm ³ . 7. The fixing device according to claim 5, wherein the felt layer having a high oil impregnation property is mainly composed of wool.