JP3801445B2 - Fixing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device, and more particularly to a fixing device having a function of supplying a release agent (oil) to a fixing roller or a pressure roller.
[0002]
[Prior art]
In image forming apparatuses such as copiers and printers, in a fixing device that fixes a toner image on recording paper, silicon oil (release agent) is usually applied to a fixing roller or a pressure roller that is pressed against the fixing roller to fix the image. Image displacement and recording paper wrapping are prevented, and stable image formation can be performed.
[0003]
As an oil application method for the roller of such a fixing device, an oil pipe having a plurality of oil discharge holes in a row is installed above the roller, oil is discharged from the discharge holes and dropped downward in the form of rain, One that is applied to a roller is known (for example, see JP-A-8-137317).
[0004]
[Problems to be solved by the invention]
However, when the oil discharged from the plurality of discharge holes of the pipe falls from the lower surface of the pipe along the outer peripheral surface of the pipe, if the installation state of the image forming apparatus main body is inclined, the pipe is also inclined. In addition, the oil is transmitted to the lower part of the pipe, and the oil dripping position set in advance is different. For this reason, there is a problem that uneven oil supply to the roller occurs, and in particular, in a portion where the oil supply amount of the roller is insufficient, there is a problem that the fixed image is displaced or the recording paper is wound.
[0005]
The present invention has been made in consideration of such circumstances, and even when the main body of the image forming apparatus is tilted, a mold release that can uniformly supply oil (release agent) to the fixing roller or the pressure roller. A fixing device having an agent supply function is provided.
[0006]
[Means for Solving the Problems]
The present invention relates to a rotating fixing roller, a pressure roller that rotates in pressure contact with the fixing roller, a heating member that heats at least one of the fixing and pressure rollers, and a liquid on at least one surface of the fixing and pressure rollers. A release agent supply unit that supplies the release agent, and the release agent supply unit includes an elongated cylindrical container that contains the release agent and has a plurality of release agent discharge holes in a line in the axial direction. The cylindrical container is installed substantially parallel to the upper side of one of the fixing and pressure rollers so that the release agent discharge hole faces upward, and the release agent discharged from the discharge hole and transmitted to the outer peripheral surface is directed downward. It is an object of the present invention to provide a fixing device characterized in that a guide portion for guiding is provided on the outer peripheral surface.
DETAILED DESCRIPTION OF THE INVENTION
[0007]
As the fixing roller and the pressure roller in the present invention, a metal cylindrical cored bar (for example, an aluminum pipe) covered with an elastic material layer (for example, a silicone rubber layer) can be used. As an example, an electric heater (for example, a halogen lamp) can be mounted in the cylindrical core metal of the roller.
[0008]
The fixing roller is driven by a drive source (for example, a motor) and rotates at a constant peripheral speed. It is preferable that the liquid release agent is supplied from the tank to the cylindrical container of the release agent supply unit by a small pump such as a piezoelectric or electromagnetic pump.
[0009]
In this case, the inner diameter of the cylindrical container is determined by the discharge capacity of the pump. For example, when the pump discharge capacity is (3 to 30 g / min), the inner diameter of the cylindrical container is suitably 5 to 10 mm. .
Although the material of a cylindrical container is not specifically limited, The commercially available pipe made from aluminum, iron, or brass can be used.
[0010]
The release agent discharge hole of the cylindrical container preferably has a diameter of 0.5 to 1.5 mmφ, and the discharge hole can be formed by, for example, pressing or laser processing. The plurality of release agent discharge holes means about 3 to 10 discharge holes.
[0011]
In addition, when supplying the release agent from one end of the cylindrical container, considering the pressure loss, the release agent discharge hole diameter is gradually increased from the upstream side to the downstream side of the cylindrical container to make the discharge amount uniform. You may make it make it.
[0012]
As shown in FIG. 4 , the guide portion may be an elongated projecting portion provided around each of the release agent discharge holes at both ends, or may correspond to each of the plurality of release agent discharge holes. It may be a long and narrow projecting portion.
Further, the guide portion may be a groove provided along a circumference passing through the release agent discharge hole in a direction orthogonal to the axis of the cylindrical container.
[0013]
The protrusion may be formed directly on the outer peripheral surface of the cylindrical container using an adhesive or the like. In this case, a thermosetting epoxy-diameter adhesive or the like can be used as the adhesive.
[0014]
In addition, the protrusion is molded into a ring shape with a resin having excellent heat resistance such as PPS (polyphenylene sulfide), PET (polyethylene terephthalate), PAI (polyamideimide), PEEK (polyetheretherketone) resin, etc. May be used.
Moreover, although the protrusion part has a trapezoidal shape, a square shape, a semicircular shape, or a polygonal shape as a cross-sectional shape, a height of about 1 to 3 mm is preferable.
[0015]
Further, the guide portion may be a groove provided corresponding to each of the release agent discharge holes at both ends, or may be a groove provided corresponding to each of the plurality of release agent discharge holes. There may be.
Further, the guide portion may be a groove provided along a circumference passing through the release agent discharge hole in a direction orthogonal to the axis of the cylindrical container.
[0016]
The groove can be formed on the outer peripheral surface of the cylindrical container by machining, and examples of the cross-sectional shape include a U-shape and a V-shape. The width and depth of the groove are preferably determined in consideration of the release agent discharge amount and the thickness of the cylindrical container.
[0017]
As the release agent, dimethyl silicone oil having a viscosity of 100 CS to 300 CS can be used, but modified silicone oil (for example, reactive silicone oil, non-reactive silicone oil, etc.) may be used. However, if the viscosity is high, pump suction becomes difficult, which is not preferable.
[0018]
The present invention will be described in detail below based on the embodiments shown in the drawings. However, this does not limit the present invention.
FIG. 1 is a perspective view of an essential part of a fixing device according to an embodiment of the present invention, and FIG. 2 is a side view thereof.
As shown in these drawings, the fixing device 100 includes a fixing roller 1 and a pressure roller 2 disposed so as to be in pressure contact with each other. Each of the fixing roller 1 and the pressure roller 2 has a rubber layer made of silicone rubber on an aluminum pipe, and includes heaters 3 and 4 made of halogen lamps inside the pipe.
[0019]
Around the fixing roller 1, an upper peeling claw 11, an upper cleaning roller 9, a fixing roller temperature detector 5, and an oil application roller 7 are disposed. Around the pressure roller 2, a lower peeling claw 12, a lower cleaning roller 10, and a pressure roller temperature detector 6 are disposed.
[0020]
The upper and lower peeling claws 11 and 12 are for peeling the recording paper wound around the rollers 1 and 2 from the surfaces of the rollers 1 and 2. The upper and lower cleaning rollers 9 and 10 are felt rollers, and are in sliding contact with the surfaces of the rollers 1 and 2 to collect offset toner adhering to the surfaces of the rollers 1 and 2.
[0021]
The oil application roller 7 is a roller having a surface made of rubber, and applies oil as a release agent to the surface of the fixing roller 1 that comes into contact therewith. The fixing and pressure roller temperature detectors 5 and 6 are thermistors and detect the surface temperatures of the fixing and pressure rollers 1 and 2 that are in contact with each other. The temperature detection results of the fixing and pressure roller temperature detectors 5 and 6 are sent to a fixing controller (not shown).
[0022]
The fixing control unit controls the operation of the power supply unit based on the detection results of the fixing and pressure roller temperature detectors 5 and 6 to turn on / off the heaters 3 and 4 which are heat sources in the rollers 1 and 2. Then, the temperature of the rollers 1 and 2 is adjusted.
[0023]
Next, a method for supplying oil to the oil application roller 7 for applying oil (liquid release completed) to the fixing roller 1 in the fixing device 100 will be described in detail.
[0024]
Oil is contained in an oil tank 20 provided at the lower part of the fixing device 100. A pump 21 installed in the upper part of the oil tank 20 supplies oil from the oil tank 20 to one end of the pipe member 22 through a tube 26. The pipe member 22 is installed above the fixing roller 1 in parallel with the fixing roller 1.
[0025]
As shown in FIG. 1, the pipe member 22 has a plurality of oil discharge holes 22a in a row at the top of the outer peripheral surface. When the pump 21 is operated, oil is discharged from the plurality of discharge holes 22 a of the pipe member 22, and is dropped along the outer periphery of the pipe member 22 onto the felt 23 for supplying oil in the form of rain. The oil may be dropped directly onto the application roller 7. The other end of the pipe member 22 is sealed.
[0026]
The dropped oil is attached to the oil application roller 7 via the felt 23.
The oil adhering to the oil application roller 7 is made uniform into a thin film by an application blade 24 made of rubber.
[0027]
Excess oil that has not adhered to the oil application roller 7 is collected by a dish-like oil pan 25 installed at the lower portion, and returned to the oil tank 20 by a tube-like shape 28 connected to the oil pan.
[0028]
The oil circulates between the oil tank 20 and the pipe member 22, and the amount of oil in the oil tank 20 is detected by the remaining oil detection sensor 27 and displayed on a display panel (not shown).
[0029]
Next, the structure and operation of the pipe member 22 will be described in detail. FIG. 3 is an explanatory view of the main part configuration of the fixing device shown in FIG. 2. The pipe member 22 has substantially the same length as the fixing roller 1 and the pressure roller. The holes 22a are provided at equal intervals, and the interval Do between the oil discharge holes 22a at both ends is set slightly shorter than the length Df of the felt 23 and the width Dp of the recording paper P.
[0030]
As shown in FIG. 3, annular rings 30 made of PPS resin are fitted and bonded to the oil discharge holes 22a at both ends as guide portions for guiding the oil downward.
The ring 30 is circumferentially provided along a circumference in a direction perpendicular to the axis of the pipes member 22 through the oil discharge hole 22a to the portion except the oil discharge hole 22a.
[0031]
Then, the oil discharged from the oil discharge holes 22a at both ends is guided downward by the ring 30 as shown in FIG. 3, and the oil discharged from the other oil discharge holes 22a is the outer periphery of the pipe member 22. It is designed to fall down along the surface.
[0032]
In such a configuration, when the image forming apparatus provided with the fixing device is inclined for some reason and the pipe member 22 is inclined accordingly, the image forming apparatus is discharged from the oil discharge holes 22a at both ends as shown in FIG. The oil is guided downward by the ring 30 and falls downward, but the oil discharged from the other oil discharge holes 22 a falls along the outer periphery of the pipe member 22, and a part of the oil causes a lateral flow due to the inclination of the pipe member 22. . However, since the ring 30 on the downstream side prevents the lateral flow, the oil is prevented from dropping to unnecessary portions.
[0033]
FIG. 6 is a front view showing a modification of the pipe member 22 shown in FIG. 3. In this case, the rings 30 are respectively provided in all the oil discharge holes 22a of the pipe member 22, and other configurations are the same as those shown in FIG. It is equivalent.
[0034]
In this example, even if the pipe member 22 is tilted, the oil discharged from the five oil discharge holes 22a is guided downward by the respective rings 30 as shown in FIG. Without being distributed evenly on the felt 23 (FIG. 3) and dropping to unnecessary portions is also prevented.
[0035]
The guide portion for guiding the oil downward has an oil discharge hole 22a in a direction orthogonal to the axis of the pipe member 22, as shown in FIGS. 7 and 8, respectively, instead of the ring 30 shown in FIGS. You may comprise the U-shaped or V-shaped groove | channel 30a formed along the circumference which passes. The groove 30a shown in FIGS. 7 and 8 has the same effect as the ring 30 shown in FIGS. 3 and 6, respectively.
[0036]
【The invention's effect】
According to the present invention, even if the image forming apparatus equipped with the fixing device is inclined, the release agent supply unit prevents the release agent from flowing laterally, so that the release agent is not supplied to an unnecessary portion. Is properly supplied.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of a fixing device according to an embodiment of the present invention.
FIG. 2 is a side view of the fixing device shown in FIG.
FIG. 3 is an explanatory diagram of a main part configuration of the fixing device shown in FIG. 1;
FIG. 4 is a front view showing an example of a pipe member of the present invention .
FIG. 5 is an explanatory diagram showing an operation of the fixing device shown in FIG. 3;
6 is a main part front view showing a modification of the embodiment shown in FIG. 1; FIG.
FIG. 7 is a front view of an essential part showing still another modification of the embodiment.
FIG. 8 is a main part front view showing still another modification of the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Heating heater 4 Heating heater 7 Oil application roller 20 Oil tank 21 Pump 22 Pipe member 22a Oil discharge hole 23 Felt 25 Oil pan 26 Tube 27 Oil remaining amount detection sensor 28 Tube 30 Ring

Claims (3)

A fixing roller that rotates, a pressure roller that rotates in pressure contact with the fixing roller, a heating member that heats at least one of the fixing and pressure rollers, and a liquid release agent on at least one surface of the fixing and pressure rollers A release agent supply unit, and the release agent supply unit includes an elongated cylindrical container that contains the release agent and has a plurality of release agent discharge holes in a line in the axial direction. A guide portion that is installed substantially parallel above one of the fixing and pressure rollers so that the release agent discharge hole faces upward, and guides the release agent discharged from the discharge hole and transmitted to the outer peripheral surface downward. On the outer peripheral surface, and the guide portion is composed of an elongated protrusion provided in a portion except the release agent discharge hole along the circumference passing through the release agent discharge hole in a direction orthogonal to the axis of the cylindrical container. A fixing device characterized by the above. A fixing roller that rotates, a pressure roller that rotates in pressure contact with the fixing roller, a heating member that heats at least one of the fixing and pressure rollers, and a liquid release agent on at least one surface of the fixing and pressure rollers A release agent supply unit, and the release agent supply unit includes an elongated cylindrical container that contains the release agent and has a plurality of release agent discharge holes in a line in the axial direction. A guide portion that is installed substantially parallel above one of the fixing and pressure rollers so that the release agent discharge hole faces upward, and guides the release agent discharged from the discharge hole and transmitted to the outer peripheral surface downward. Is provided on the outer peripheral surface, and the guide portion is formed of a groove provided around each of the plurality of release agent discharge holes . The fixing device according to claim 2 , wherein the guide portion includes a groove provided along a circumference passing through the release agent discharge hole in a direction orthogonal to the axis of the cylindrical container.

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