JPH04120573A - Fixing device - Google Patents

Abstract

PURPOSE:To suppress an offset and to improve the durable life of a heating roller by constituting a 2nd silicone oil applied roller of a heat pipe roller and bringing this roller into indirect contact with the heating roller. CONSTITUTION:The 2nd silicone oil applied roller 14 is the heat pipe roller. The heat of the heating roller 1 is, therefore, easily transferred by the applied roller 14 which comes into indirect contact with the heating roller via the 1st silicone oil applied roller 7, by which the temp. distribution in the axial direction of the heating roller 1 is uniformized. Then, the part B of the heating roller 1 where the transfer paper P of a small size is not passed is prevented from being heated to a high temp. in this way even if the transfer paper P of the small size is passed before the passage of the transfer paper P of a large size by the size change of the transfer paper P after continuous passing of paper for copying. The generation of an offset developing at the time of fixing in the part D of the transfer paper P is substantially obviated. The offset is suppressed in this way and the durable life of the heating roller is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a fixing device used in copying machines, printers, facsimile machines, etc.

Moxibustion] Nou Kusakaki Conventionally, there is a fixing device of this type as shown in FIG. A heating roller 1 and a pressure roller 2 form a first fixing section, and a heating roller 1 and a plurality of pressure rollers 5 form a second fixing section.

The heating roller 1 is capable of forward and reverse rotation so that the transfer paper (plain paper) P can be fixed at the first fixing section when rotating forward, and the transfer paper (special paper) P can be fixed at the second fixing section when rotating in reverse. It is designed to be driven. Also, the first step is to apply silicone oil to the heating roller 1. The second silicone oil application roller 7.8 is in contact with the first silicone oil application roller 7 on the surface of the heating roller 1, and the second silicone oil application roller 8 is in contact with the surface of the first silicone oil application roller 7. It is arranged so that it can rotate freely.

1O is a coating felt placed in contact with the surface of the second silicone oil coating roller 8, and its lower part is immersed in the silicone oil in the silicone oil reservoir 11. 9 is a cleaning/silicone oil recovery roller, and 13 is a scrubber blade placed in contact with the surface of the roller 9, which scrapes off foreign substances such as toner and paper dust that have been offset on the surface of the roller 9. 3 is a cleaning roller.

However, in the conventional fixing device described above, when changing the size of the transfer paper after one continuous copy is passed, the temperature distribution in the axial direction of the heating roller 1 becomes quite uneven.

In particular, when passing a small-sized transfer paper before passing a dog-sized transfer paper, there is less heat balance in the area other than the area where the paper is passing, resulting in a high temperature, and the gap between the high-temperature area and the low-temperature area of the area where the paper is passing. Temperature deviation becomes large and offset phenomenon tends to occur.

In extreme cases, this may have an adverse effect such as shortening the life of the heating roller.

In order to prevent the above-mentioned phenomenon, there are currently some devices that increase the thickness of the heating roller and aim for the heat pipe effect, but in this case, on the other hand, the temperature rise time is slow when the power is turned on. This phenomenon has occurred, and the problem has become unavoidable. It has also been proposed that the heating roller be made of a heat pipe roller.
There remain many concerns and problems regarding safety when using a heat pipe roller as a heat source.

Therefore, the present invention solves the above-mentioned conventional problems, and makes it possible to equalize the temperature distribution in the axial direction of the heating roller caused by changing the size of the transfer paper after one continuous copying, thereby eliminating the offset phenomenon. It is an object of the present invention to provide a fixing device that is less likely to cause such occurrences, can improve the durability life of a heating roller, has a quick temperature rise when the power is turned on, and can ensure safety.

In order to achieve the above-mentioned object, the first invention of this application includes a pressure roller rotatably disposed in contact with a heating roller,
First, applying silicone oil to the heating roller. Second
A fixing device in which a silicone oil application roller is rotatably disposed with the first silicone oil application roller in contact with the surface of the heating roller and the second silicone oil application roller in contact with the surface of the first silicone oil application roller. The second silicone oil application roller is a heat pipe roller.

In a second invention, a plurality of pressure rollers and a pressure roller are rotatably arranged in contact with different positions on the surface of a heating roller, and a first fixing section is formed by the heating roller and the pressure roller. At the same time, a heating roller and a plurality of pressure rollers are used to
A fixing section is formed, and the heating roller is capable of forward and reverse rotation so that the transfer paper can be fixed at the first fixing section when rotating forward, and the transfer paper can be fixed at the second fixing section when rotating in reverse;
Applying silicone oil to the heating roller; either a first silicone oil application roller or a first silicone oil application roller on the surface of the heating roller and a second silicone oil application roller on the surface of the first silicone oil application roller; The fixing devices, which are rotatably disposed in contact with each other, are characterized in that the second silicone oil application roller is a heat pipe roller.

211 In the first and second inventions, since the second silicone oil application roller is a heat pipe roller, it is possible to pass a large size transfer paper by changing the size of the transfer paper after one continuous copy paper is passed. Even when a small-sized transfer paper is passed in front of the paper, the heat is easily transferred by the second silicone oil application roller, which is in indirect contact with the heating roller and the first silicone oil application roller, and the temperature remains constant. Uniformity is promoted and the temperature distribution in the axial direction is made uniform.

S''L■ 1 and 2 show a first embodiment of the invention.

In FIG. 1, reference numeral 14 denotes a second silicone oil application roller which is disposed in indirect contact with the heating roller 1 via the first silicone oil application roller 7, and serves as a heat pipe roller.

15 are first and second silicone oil application rollers 7.14
The silicone oil receiver described later is a silicone oil application unit having a reservoir, etc., and is detachably attached to the fixing device unit from its front side (as shown in FIG. 1).

In FIG. 2, reference numeral 16 denotes a press-contact leaf spring for holding the felt in place, which is attached to the surface of an L-shaped holding plate 17 for holding the coated felt. 18 is a coating felt disposed in contact with the surface of the second silicone oil coating roller 14; 19 is a U-shaped felt material disposed in contact with the back surface of the felt 18; 19 is disposed within the inverted U-shaped holding plate 20, and the coated felt 18 is wound so as to cover the holding plate 20 and the felt material I9 more than one circumference. Then, with the side edge of the winding in contact with the felt material 19 in contact with the roller 14, the lower edge of the winding of coated felt]8 is connected to the holding plate 21 and the holding plate 20,
The upper edge and the other side edge of the winding are held by a holding plate 17 and a holding plate 20. The winding ends of coated felt I8 are attached to both holding plates 1.
The silicone oil receiver hangs down into the reservoir 22 from the gap 7.21 in a curved manner.

23 and 24 are scraper blades disposed in contact with the surface of the roller 14, and when the coated felt 18 is held by the holding plate +7, 20, and 21 on the base end thereof, the holding plate 17 and the holding plate 20 are A coated felt 18 is sandwiched between the holding plate 21 and the holding plate 20, and is fixed above and below the holding plate 21 and the holding plate 20. The scraper blades 23, 24 are made of a thin metal plate, such as heat-resistant and resilient phosphor bronze. A silicone oil supply pipe 26 is connected inside the U-shaped felt material 19, and silicone oil is supplied from a supply section (not shown) to the felt material 19 through the pipe 26. The silicone oil supplied to is supplied from the felt material 19 to the application felt 18. 27 is a separation roller, which may be replaced with a separation claw. 28 is a thermistor, 29
is a temperature fuse, which is installed close to the heating roller 1, and constitutes a safety protection circuit in the event of a failure.

In this first embodiment configured as described above,
Since the second silicone oil application roller 14 is a heat pipe roller, the heat of the heating roller 1 is easily transferred by the application roller 14 that comes into indirect contact with the first silicone oil application roller 7. As a result, temperature uniformity is promoted, and the temperature distribution in the axial direction of the heating roller I is made uniform. Therefore, by changing the size of the transfer paper P after one continuous copy is passed, as shown in Fig. 4, the small size transfer paper P (for example, A4 size) is changed before passing the large size transfer paper P (for example, A3 size). Even when the paper is passed through, the part B of the heating roller 1 where the J) size transfer paper P is not passed becomes particularly hot unlike in the past, and for example, when the small size transfer paper P is The temperature deviation between the portion A through which the paper is passed and the low temperature portion is reduced. Therefore, even if a large size transfer paper P is passed through, an offset phenomenon occurs when the transfer paper P passes through the 0 section of the heating roller 1 corresponding to the passing of the transfer paper P in the B section and is fixed on the D section. Almost nothing happens.

Further, in the first embodiment, the silicone oil supplied from the supply pipe 26 to the felt material 19 is transferred from the felt material 19 to the contacting coating felt 18, and from this coating felt 18 to the contacting second silicone oil application roller 14. is supplied. The applied silicone oil is regulated to a very small and constant amount by the upper scraper blade 23 on the application roller 4, and then applied to the surface of the heating roller 1 via the roller 7.

The excess silicone oil due to the above-mentioned regulations is sent from the tip side of the application felt 18 to the silicone oil reservoir 22 and stored therein. On the other hand, foreign matter such as offset toner or paper powder adhering to the heating roller 1 during the coating is transferred to the application roller 14 via the roller 7, or these foreign matter are scraped off by the lower scraper blade 24, and the silicone oil receiver is removed. It is collected in the reservoir 22.

FIG. 3 shows a second embodiment of the invention. This second embodiment includes the silicone oil application unit 15 of the first embodiment as is, and the fixing section in which this application unit 15 is installed is different from the conventional first fixing section and second fixing section as shown in FIG. This embodiment differs from the first embodiment in that it consists of two parts.

Therefore, the same parts as in FIGS. 1 and 2 showing the first embodiment and FIG. 5 showing the conventional example are given the same reference numerals, and the explanation thereof will be omitted. In this second embodiment as well, the effect of reducing the temperature deviation in the axial direction of the heating roller 1 by the second silicone oil applying roller 14, which is a heat pipe roller, is the same as in the first embodiment. Further, the difference from the first embodiment in the supply operation of the applied silicone oil is that the applied silicone oil is regulated to a very small and constant amount on the application roller 14 by the lower scraper blade 24, while foreign substances such as offset toner are It is scraped off by the upper scraper blade 23, and both blades 23, 24 perform an action opposite to that during normal rotation.

Furthermore, the invention according to claim 1 is such that the second silicone oil application roller is constituted by a heat pipe roller, and is brought into indirect contact with the heating roller via the first silicone oil application roller. Therefore, it is possible to equalize the temperature distribution in the axial direction of the heating roller caused by changing the size of the transfer paper after one continuous copying, and it is possible to make the offset phenomenon unlike the conventional one less likely to occur. Further, the durability life of the heating roller is improved by reducing the temperature deviation as described above. Only 4
Also, since a thin roller can be used as the heating roller, the temperature rises quickly when the power is turned on.

Furthermore, since the second silicone oil application roller serving as a heat pipe roller and the heating roller do not come into direct contact with each other, and the first silicone oil application roller is interposed between the two, the heating roller may become uncontrollable. Even if the safety protection circuit is activated due to a rise in temperature, damage to the second silicone oil application roller is extremely small, and safety can be ensured. Furthermore, in addition to this, it can be easily manufactured by partially improving existing equipment, and the excellent effect of reducing manufacturing costs can also be obtained.

In addition to the above-mentioned effects, the invention according to claim 2 also provides the same effects when using the second fixing section.

[Brief explanation of drawings]

Fig. 1 is a front view showing a first embodiment of the present invention, Fig. 2 is a partial perspective view of the main parts of the same as above, Fig. 3 is a front view showing a second embodiment of the invention, and Fig. 4 is an operational view. FIG. 5 is a perspective view of a main part for explanation, and a front view showing a conventional example. 1... Heating roller 2... Pressure roller 5... Pressure roller 7... First silicone oil coating roller and pipe roller)

Claims (1)

[Claims] 1. A pressure roller is rotatably disposed in contact with the heating roller, and a first step for applying silicone oil to the heating roller.
, the second silicone oil application roller is rotatably disposed such that the first silicone oil application roller contacts the surface of the heating roller, and the second silicone oil application roller contacts the surface of the first silicone oil application roller. A fixing device characterized in that the second silicone oil application roller is a heat pipe roller. 2. A plurality of pressure rollers and pressure rollers are rotatably arranged in contact with different positions on the surface of the heating roller, and the heating roller and the pressure roller form a first fixing section, and the heating roller A second fixing section is formed by a plurality of pressure rollers, and the heat roller fixes the transfer paper at the first fixing section when rotating in the normal direction, and fixes the transfer paper at the second fixing section when rotating in the reverse direction. The first and second silicone oil application rollers are capable of forward and reverse rotation, and apply silicone oil to the heating roller. 1. A fixing device rotatably disposed in contact with the surfaces of first silicone oil application rollers, wherein the second silicone oil application roller is a heat pipe roller.