KR100810734B1 - Electrophotographic image forming apparatus - Google Patents

Abstract

An electrophotographic image forming apparatus according to the present invention comprises: a pressure roller installed to apply pressure in an upward direction; A guide member installed on an upper portion of the pressure roller to form a pressing curved portion; A heat generating means stacked on the pressure curved portion of the guide member to provide heat generation using a thin film heater; And a sleeve mounted to surround the outer surface of the guide member so as to receive heat, and to transfer and heat-fix the recording material to be driven by friction driving in a state facing the pressure roller. .

According to the present invention as described above, the heating means including the thin film heater is formed on the upper surface of the guide member, thereby utilizing the entire surface of the guide member as a heating plate, so that the heat fixing operation is performed in a state where the sleeve is sufficiently preheated. In addition to the effect that the output is possible, the heat generating means is not rubbed with the sleeve without being pressed by the pressure roller and the life is extended, and the working time is shortened due to the high-speed heat generation using the thin film heater. It works.

Description

Electrophotographic Image Forming Apparatus {Electro Photographic Type Image Forming Apparatus}

1 is a cross-sectional view schematically showing the internal structure of an image forming apparatus using a conventional halogen lamp.

2 is a cross-sectional view schematically showing the internal structure of an image forming apparatus using a conventional plate heater.

3 is a cross-sectional view schematically showing the internal structure of the image forming apparatus using a thin film heater according to an embodiment of the present invention.

4 is a cross-sectional view schematically showing the internal structure of an image forming apparatus using a thin film heater according to another embodiment of the present invention.

Figure 5 is an enlarged cross-sectional view showing a cross-sectional structure for explaining an embodiment of the heat generating means according to the present invention.

Figure 6 is an enlarged cross-sectional view showing a cross-sectional structure for explaining another embodiment of the heat generating means according to the present invention.

7 to 9 are exemplary views showing various embodiments of a conductor pattern formed on a thin film heater according to the present invention.

10 to 11 are exemplary views showing an embodiment of various arrangement patterns of the metal pad and the thin film heater according to the present invention.

12 is a schematic view showing the specifications of the specimen for testing the heating characteristics of the heating means according to the present invention.

FIG. 13 is a graph measuring a temperature change value according to time displacement in a state in which a constant current (50W) is applied to the specimen of FIG. 12. FIG.

14 is a graph measuring a temperature change value according to the displacement of the amount of current applied for the time (10 seconds) specified in the specimen of FIG.

<Description of the symbols for the main parts of the drawings>

110: pressure roller 120: heating means

122: insulating film 123: thin film heater

124: conductor pattern 125: metal pad

127: protective layer 130: guide member

131: pressing surface portion 132: horizontal pressing surface

133: preheat wing 140: sleeve

141: film layer 143: metal tube

150: flange member 151: collar washer

153: fixed film sliding portion

The present invention relates to an electrophotographic image forming apparatus, and more particularly, a heat generating means including a thin film heater is formed on an upper surface of a guide member, thereby utilizing the entire surface of the guide member as a heating plate and installing a preheating wing. An electrophotographic image forming apparatus adapted to perform a heat fixing operation in a sufficiently preheated state.

In general, a fixing apparatus used for fixing toner particles transferred to a print medium such as a laser printer or a digital copier has a structure as shown in FIG.

1 is a cross-sectional view schematically showing the internal structure of an image forming apparatus using a conventional halogen lamp.

The conventional fixing device has a heat generating portion of the cylindrical metal tube 12 and the halogen lamp 11 provided in the center of the inside, the coating layer 13 made of Teflon or the like is formed on the surface of the cylindrical metal tube 12.

The radiant heat is generated from the halogen lamp 11 inside the cylindrical metal tube 12 of the heat generating portion, so that the cylindrical metal tube 12 is indirectly heated.

Under the cylindrical metal tube 12, the pressure roller 15 is positioned with the printing paper 14 therebetween.

The pressure roller 15 presses the printing paper 14 with a constant force by the pressure spring 16.

Accordingly, the toner 17 in the form of powder powder is fixed on the printing paper by the heat generated by the heat generating unit, and an image is formed on the printing paper.

Such a conventional fixing device requires a significant preheating time of several tens of seconds or more in order to raise the cylindrical metal tube 12 at room temperature to the temperature at which the toner 17 is fixed at the time of power on / off of a printer and a digital copier.

This is an indirect heating method in which the heat of the heat generating unit is transferred to the printing paper as radiant heat via the atmospheric or cylindrical metal tube 12, and also, when switching from the standby mode to the operating mode for printing, to raise it to the fixing temperature for several tens of seconds or more. There is a problem in that the waiting time for users is long because time is required.

In addition, the conventional fixing device has a problem that the initial power used to operate the halogen lamp is 1.0Kw ~ 3Kw high power, the power consumption is large.

Accordingly, a film heating system as disclosed in Japanese Patent Laid-Open Nos. 63-212182, 2-157878, 4-44075 to 4-44083, 4-204980 to 4-204984, etc. is adopted. A heating fixture has been proposed.

Such a heating fixing device is a heating member such as a ceramic heater fixedly disposed by a pressure roller or a pressure member (hereinafter referred to as a heating body) and a heat resistant film serving as a rotating member for heating (hereinafter referred to as a fixing film or sleeve). ) Is brought into close contact, whereby the fixing film is slidably rotated.

Thereafter, a toner image is formed and the recording material having the toner is introduced into the fixed nip which acts as a pressure contact nip configured so that the fixed film is disposed between the heating body and the pressure roller, and the introduced recording material is conveyed together with the fixed film. Thereby, the toner image is heat-pressed and fixed to the surface of the recording material as a permanent fixed image by the pressure of the fixed nip portion and the heat applied from the heating body through the fixed film.

The heating fixing device adopting the film heating system can use a linear heating element of a small heat capacity such as a ceramic heater as the heating element, and can also use a thin film of a small heat capacity as the fixing film, thereby saving power. It is possible to reduce the waiting time (ie, to start quickly). Incidentally, the method of providing a drive roller on the inner surface of the fixed film and the method of using the pressure roller as the drive roller and thus driving the fixed film by the frictional force between the drive roller and the pressure roller are heat-fixed employing a film heating system. Known as a fixed film drive system to be used in the apparatus.

FIG. 2 is a cross-sectional view schematically showing the internal structure of a conventional image forming apparatus using a plate heater, illustrating an example of a heat fixing apparatus employing a pressure roller drive system and a film heating system.

In the same figure, reference numeral 20 denotes a heating assembly, and reference numeral 22 denotes an elastic pressure roller acting as a pressure member. The elastic pressure rollers 22 and the heating assembly 20 arranged in parallel up and down are in pressure contact with each other to form the fixed nip N.

The heating assembly 20 serves as a flexible rotating body in contact with the heater 23, the film guide 25, which serves as a guide member for supporting the heater 23, the heater 23, which serves as a heating member, and It is an assembly comprised of the cylindrical fixing film 21 containing the film guide 25, the flange member 26 etc. which hold | maintain the fixing film 21 by the both ends, and fit in the film guide 25.

At this time, the heater 23 is a rectangular ceramic heater having a longitudinal length extending along a direction perpendicular to the conveying direction of the recording material P, the heat capacity of which is small in total, and the heater 23 accommodates the power supply. To generate heat.

In addition, the film guide 25 is a groove-shaped rectangular member whose cross section is substantially semicircle, and the longitudinal side part extends in the direction perpendicular to the conveying direction of the recording material P. For example, the film guide 25 is Made of phenolic thermosetting resin. The heater 23 is fitted into the heater fitting groove formed in the longitudinal direction at the center of the lower surface of the film guide 25 and is thus fixedly supported.

The cylindrical fixing film 21 is loosely fitted to the film guide 25 to which the heater 23 is fitted.

The flange member 26 has a collar washer portion 26a for holding the end of the cylindrical fixing film 21 and adjusting the movement of the fixing film in the axial direction thereof, and a cylindrical fixing film 21 which is substantially arc and supports the fixing film end. And a sliding portion 26b fitted to the inside of the end portion thereof. The flange member 26 is fitted to both ends of the film guide 25 and is thus fixed.

The elastic pressure roller 22 is rotatably bearing supported between the side covers (not shown) of the heating fixture, and the heating assembly 20 has the heater 23 side downward and is parallel to the elastic pressure roller 22. And the heating assembly 20 and the elastic pressure roller 22 are pressurized with each other by pressure means not shown with respect to the elasticity of the pressure roller 22, and the heater 23 and the pressure roller 22 are accordingly The fixed nip N, which is in pressure contact with each other, is thus arranged between the heater 23 and the pressure roller 22, thereby acting as a pressure contact nip of a predetermined width. Is formed due to elastic deformation.

The elastic pressure roller 22 is rotatably driven counterclockwise as indicated by the arrow by driving means not shown. By rotatably driving the pressure roller 22, rotational force is applied to the fixed film 21 at the fixed nip N due to the frictional force between the pressure roller 22 and the outer surface of the fixed film 21. Thereafter, the inner surface of the fixing film 21 substantially corresponds to that of the pressure roller 22 as the inner surface of the fixing film 21 is in intimate contact with the lower surface of the heater 23 at the fixing nip N and slides along it. At the circumferential speed, the circumference of the film guide 25 is rotated clockwise as indicated by the arrow (pressure roller drive system).

The movement of the rotation fixing film 21 in the axial direction (the longitudinal direction) is adjusted by the collar washer portion 26a of the flange member 26, and the inside of the end of the fixing film 21 is the flange member 26. It is supported and rotatably guided by the sliding portion 26b of the.

Thereafter, the fixed film 21 is rotatably driven by the pressure roller 22, and in a state where the temperature reaches a predetermined temperature due to charging of the heater 23, an unfixed toner image T is formed. And the recording material P having the same is introduced into the position between the pressure roller 22 and the fixing film 21 at the fixed nip N in the non-shown image forming portion, the recording material P is the recording material P Are superimposed and pass through the fixed nip N together with the fixed film 21 in a state of being in close contact with the outer surface of the fixed film 21.

Heat energy of the heater 23 is applied to the recording material P through the fixing film 21 while the recording material P passes through the fixed nip N, whereby the non-fixed toner of the recording material P The image T is subjected to a hot melt fixing step. Thereafter, the recording material P passing through the fixed nip N is separated from the surface of the fixed film 21 at the separation point A and then discharged.

However, the image forming apparatus of the related art having the above structure has recently been limited in the heat generation area of the heater despite the demands of the increase in the printing speed. There was a problem that the fixing operation is not performed properly because the heating time is not enough.

In addition, the conventional technology uses a ceramic substrate having low thermal conductivity as the upper substrate of the heating heater, which causes a large temperature difference between the passage region and the non-pass region of the recording material.

In addition, the prior art has a problem that the life is shortened as the heater is formed on the bottom surface of the film guide is subjected to the pressing force by the pressure roller and the continuous friction with the sleeve is made.

In addition, the prior art has a problem that the preheating time of the heater takes a long time, the working waiting time is long.

An object of the present invention for solving the above-described conventional problems is to form a heating means including a thin film heater on the upper surface of the guide member, while utilizing the entire surface of the guide member as a heating plate at the same time the bottom shape of the guide member curved curved surface By forming a portion, it is possible to secure a more expanded heat fixing area than conventional ceramic heaters, while the electrophotographic method to perform the heat fixing operation while the sleeve is sufficiently preheated by the preheating wing structure of the guide member An image forming apparatus is provided.

Another object of the present invention is a structure in which the heat generating means is formed on the upper surface of the guide member, the life is extended as it is not rubbed with the sleeve without being subjected to the pressing force by the pressure roller, the work standby due to the characteristics of high-speed heat using a thin film heater The present invention provides an electrophotographic image forming apparatus which reduces time.

An electrophotographic image forming apparatus according to the present invention for achieving the above object includes a pressure roller installed so that a pressure is applied in an upward direction; A guide member installed on an upper portion of the pressure roller to form a pressing curved portion; A heat generating means stacked on the pressure curved portion of the guide member to provide heat generation using a thin film heater; And a sleeve mounted to surround the outer surface of the guide member so as to receive heat, and to transfer and heat-fix the recording material to be driven by friction driving in a state facing the pressure roller. .

Here, the guide member has a predetermined width bottom to form a pressing curved portion, and forms a preheating wing extending to at least one end of the left and right ends of the pressing curved portion so that the sleeve is preheated before entering the pressing curved portion. It is characterized by.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view schematically showing the internal structure of the image forming apparatus using a thin film heater according to an embodiment of the present invention, the present invention as shown in the figure is a pressure roller 110 is installed so that the pressure acts in the upper direction ), A guide member 130 formed on the pressure roller 110 to form a pressing curved portion 131 to be compressed, and a thin film laminated on the pressing curved portion 131 of the guide member 130. Heat generating means 120 to provide heat generation using the heater 123, and is mounted in a form surrounding the outer surface of the guide member 130 receives heat, and drive friction in a state facing the pressure roller 110 And a flange member 150 coupled to guide the driving trajectory and the separation of the sleeve 140 at both ends of the guide member 130 so as to transfer and heat settle the recording material. artillery It is.

First, the pressure roller 110 is made of an elastic material capable of elastic deformation, and as shown in Figure 3 when the pressing force is applied in the ground state with the upper guide member 130, the pressure portion is inverted shape Is transformed into.

At this time, the area of the pressure roller 110, which is recessed inversely, and the pressure curved portion (), which is grounded, has a limited ground area due to the problem that the conventional ceramic heater has to be manufactured in a plate shape. You have the advantage of letting it go.

Next, the guide member 130 is subjected to heat conduction through the heat generating means 120 stacked on the upper surface, a predetermined section of the bottom forms a pressing curved portion 131, of the pressing curved portion 131 The preheating wing 133 extending to at least one of the left and right ends is formed.

At this time, the shape of the pressurized curved portion 131 is an actual ground section in which heat is settled, and the heating area is significantly wider than when using a conventional ceramic heater, so that high-speed output of an electrophotograph is possible.

In addition, the preheat wing 133 is formed to be the same as the inner curvature of the sleeve 140 is wrapped around the outer surface of the guide member 130, the sleeve 140 is the bottom surface of the guide member 130 It will be preheated before entering.

The guide member 130 may be a conductive metal made of aluminum, stainless steel or an alloy of aluminum and stainless steel having excellent thermal conductivity.

In this case, the guide member 130 may be made of a non-conductive material having excellent thermal conductivity and ensuring mechanical strength and durability.

Next, the heat generating means 120 includes a thin film heater 123 capable of driving low power (eg, 400 W, etc.). The thin film heater 123 generates heat at a very high speed when external power is supplied. As a characteristic, it is possible to shorten the waiting time of work due to preheating of a printer, a copy machine, and the like.

The heat generating means 120 is a thin film is deposited, because it is formed to a very thin thickness it is possible to reduce the power consumption while reducing the size of the device using the electrophotographic method.

Next, the sleeve 140 is a thermosetting resin (or a super engineering plastic) is used, is manufactured in a circular frame shape is loosely fitted to the guide member 130 to be mounted outside.

In this case, the sleeve 140 may be manufactured in the form of a thin cylinder of a metal material, that is, the thermosetting resin (or super engineering plastic) film layer 141 is covered on the outer diameter of the metal tube 143.

In this case, the metal tube 143 is made of a material having excellent thermal conductivity, and serves to maintain the heat conducted from the heat generating means 120 and the guide member 130, thereby improving thermal efficiency, thereby recording the hourly recording material. The output of (P) is improved.

Next, the flange member 150 has a collar washer 151 for holding the end of the sleeve 140 and adjusting the movement of the sleeve 140 in the axial direction thereof, and is substantially circular and both ends of the guide member 130. And a sliding portion 153 that is coupled to and slides with the end of the sleeve 140.

Figure 4 is a cross-sectional view schematically showing the internal structure of the image forming apparatus using a thin film heater according to another embodiment of the present invention, the present invention as shown in the figure is a guide member installed on the upper portion of the pressure roller 110 The bottom surface of the 130 may form a horizontal pressing surface 132 for a predetermined period, and the wing portion 133 may be formed to extend to any one end of the horizontal pressing surface 132.

Figure 5 is an enlarged cross-sectional view showing a cross-sectional structure for explaining an embodiment of the heating means according to the present invention, the heating means 120 of the present invention is installed on the back of the guide member 130 made of a non-conductive material An example is explained.

Heat generating means 120 of the present invention as shown in the drawing is a guide member 130 made of a non-conductive material, and is mounted in the form of a thin film on the outer surface of the guide member 130 is supplied with power from the outside to itself electric Electrical bonding is made to the thin film heater 123 which is instantaneously heated at high temperature by instantaneous heating according to a resistance, and the power supplied from the outside may be uniformly applied to the entire surface of the thin film heater 123. The metal pad 125 and the metal pad 125 and the thin film heater 123 are formed of a protective layer 127 coated to a predetermined thickness so as to be protected from an external environment.

At this time, the material of the guide member 130 of the non-conductive material may be used, such as heat-reinforced plastic, heat-resistant resin, ceramic, glass, porcelain, stone, etc. that withstand at least 250 ℃ or more.

Figure 6 is an enlarged cross-sectional view showing a cross-sectional structure for explaining another embodiment of the heat generating means according to the present invention, an example in which the heat generating means 120 of the present invention is installed on the back of the guide member 130 made of a conductive material It explains.

Heat generating means 120 of the present invention as shown in the drawing is coated with a predetermined thickness on the guide member 130 made of a conductive material, the inner surface of the guide member 130 is provided with electrical insulation properties and at the same time excellent thermal conductivity The insulating film 122 and the thin film heater 123 mounted in the form of a thin film in the lower portion of the insulating film 122 is supplied with power from the outside and instantaneously generates high temperature by instantaneous heating according to its own electrical resistance. The metal pad 125 may be electrically bonded to the thin film heater 123, and may have a specific pattern such that power supplied from the outside may be uniformly applied to the entire surface of the thin film heater 123 and the metal pad 125. ) And the thin film heater 123 is composed of a protective layer 127 coated to a predetermined thickness so as to be protected from the external environment.

Here, the thickness of the guide member 130 made of the conductive material is preferably made of 1 mm ~ 3 mm, as a material such that the metal, such as aluminum, stainless steel or an alloy of aluminum and stainless steel to be used Can be.

At this time, as shown in FIGS. 5 and 6 by forming a conductor pattern 124 to help supply current on the thin film heater 123, the generated heat is uniformly supplied to the entire surface of the thin film heater 123 In addition, it is possible to make the heat generating property stable.

Hereinafter, required for each component such as the insulating film 122, the thin film heater 123, the conductor pattern 124, the metal pad 125 and the protective layer 127 constituting the heat generating means 120 of the present invention The physical properties and structural conditions will be described in more detail as follows.

First, the insulating film 122 is made thinner as much as possible so that the heat generated from the thin film heater 123 can be conducted to the guide member 130 at a high speed, and also between the guide member 130 and the thin film heater 123. An insulating film using a ceramic material or a polymer material such as alumina (aluminum oxide, Al 2 O 3) or magnesia (magnesium oxide, MgO) or the like, or a mixed material of the two insulating films may be used for electrical insulation.

In addition, the insulating layer 122 may have a thin thickness such that heat generated from the thin film heater 123 may be conducted to the guide member 130 at a high speed, and the guide member 130 and the thin film heater 123 may be used. ) 0.5 μm to 500 μm, in particular 0.5 μm to 200 μm, is sufficient to electrically insulate the liver, and thickness may vary depending on the material.

The conditions of the insulating film 122 is as follows.

First, the insulating film 122 must electrically insulate between the guide member 130 and the thin film heater 123, and the thin film heater 123 to electrically isolate the thin film heater 123 supplied with external power. When the voltage of about 100V is applied, the breakdown of the insulating film 122 should not occur and the electrical leakage current of the insulating film 122 should be 20 μA or less.

In addition, when the high temperature heat is generated in the thin film heater 123, the insulating film 122 is in contact with the insulating film 122 and the guide member 130 so as not to physically detach from the guide member 130 and the thin film heater 123, respectively. The contact between the insulating film 122 and the thin film heater 123 should be excellent.

In addition, when the high temperature heat is generated in the thin film heater 123, the insulating film 122 does not cause a chemical reaction with the guide member 130 and the thin film heater 123, respectively, and the surface roughness of the insulating film 122 should be excellent.

That is, when the surface roughness of the insulating film 122 is not excellent, since the insulating film 122 affects the electrical resistivity of the thin film heater 123, the insulating film 122 affects the electrical resistivity of the thin film heater 123. It is desirable to have a surface roughness of a degree that does not affect.

In order to satisfy the conditions as described above, the insulating film 122 is an oxide insulating film obtained by oxidizing the surface of the guide member 130 of a metal material such as aluminum or stainless steel with an arc, or a ceramic, One or both of an insulating film coated with glass, porcelain, or the like, or a polymer insulating film coated with a polymer-based material (Polyimide, Polyamide, Teflon, PET, etc.) on the surface of the guide member 130 made of metal such as aluminum or stainless steel. An insulating film or the like having at least two branches formed on the surface of the guide member 130 is used.

An embodiment of a method of forming an oxide insulating film is as follows.

First, electric energy such as an arc is applied from the outside to the surface of the guide member 130 made of metal such as aluminum (Al) or beryllium (Be) or titanium (Ti) or stainless steel (immersed in an alkaline electrolyte solution). The metal atoms on the surface of the guide member 130 and the external oxygen cause an electrochemical reaction to be formed by converting the characteristics of the surface of the guide member 130 into an oxide film.

As the oxide insulating layer, Al 2 O 3, ZrO 3, Y 2 O 3, or the like may be used, and the oxide insulating layer may be formed on the guide member 130 by using a plasma spray coating method.

Hereinafter, an embodiment of the process of forming the oxide insulating film on the guide member will be described.

First, the concentration of the alkaline electrolyte solution filled in the bath is evaluated, and the aluminum is connected to the guide member 130 made of aluminum so that external power can be supplied to the guide member 130 made of aluminum. The guide member 130 of the material is immersed in the alkali electrolyte in the container, and then external power is supplied to the guide member 130 of the aluminum material to oxidize the surface of the guide member 130 of the aluminum material.

Next, an arc is generated on the surface of the aluminum guide member 130 as a strong power source having a high frequency alternating current (AC) shape is applied to the aluminum guide member 130 by an oxide insulating film forming process. Accordingly, an oxide insulating layer having a high oxidation density and a very small pinhole concentration is formed on the surface of the guide member 130 of aluminum.

Aluminum oxide may be formed on the surface of the guide member 130 made of aluminum material or titanium oxide may be formed on the surface of the guide member 130 made of titanium material, or the beryllium material guide member 130 may be formed using the oxide film forming process. Beryllium oxide can be formed on the surface.

On the other hand, the polymer insulating film is formed by coating a polymer-based material having a uniform thickness to ensure electrical insulation on the surface of the guide member 130 of the metal material.

In particular, the polymer insulating film should be less thermally deformed when heat is generated in the thin film heater 123. In addition, the polymer insulating film should have excellent contactability so that physical desorption from the guide member 130 and the thin film heater 123 does not occur when the high temperature heat is generated in the thin film heater 123, respectively, and the guide member 130. And do not cause a chemical reaction with the thin film heater 123, respectively, and the surface roughness should be excellent.

An embodiment of the process of forming the polymer insulating film will be described below.

First, the polymer insulating layer is formed using a liquid organic polymer material, and is coated with a uniform thickness on the surface of the guide member 130 of a metal material.

Here, as the coating method, a spin coating method, a spray coating method, a dipping coating method, a screen printing method, or the like is used.

In addition, the polymer material may be a polyimide-based material, a polyamide-based material, a teflon-based material, a paint-based material, silver-ston, Tefgel-S ( tefzel-s), epoxy, rubber, etc. may be used, or a material that is sensitive to ultraviolet rays (UV) may also be used.

For example, one embodiment of a process of forming a polyimide-based material on the guide member 130 by spray coating is as follows.

First, the guide member 130 is organically washed with acetone, isopropyl alcohol (IPA), and the like, and then the guide member 130 is rotated at a high speed (for example, 2,000 rpm or more), and is made of polyimide. After spraying the material on the guide member 130, the polyimide-based material coated on the surface of the guide member 130 is heat treated.

The polymer insulating film having a high thermal stability and a glassy temperature (GT) of 300 ° C. or more is formed on the surface of the guide member 130 by the spray coating method of forming a polymer insulating film.

In addition, by slowly cooling the polyimide-based material during the heat treatment of the polyimide-based material, the adhesion between the polymer insulating film and the guide member 130 is excellent, and the polymer-based material is coated on the surface of the guide member 130 during the spray coating process. The thickness uniformity is excellent, and the pinhole concentration of the polymer insulating film is very small, so that no electric leakage current is generated.

On the other hand, the double insulating film of the oxide insulating film and the polymer insulating film is formed by forming an oxide insulating film on the surface of the guide member 130 of the metal material and then coating a polymer-based material with a uniform thickness on the oxide insulating film or vice versa The polymer-based material may be coated on and an oxide insulating film is formed thereon.

The total thickness of the double insulating film of the oxide insulating film and the polymer insulating film is the thickness of the result of forming the oxide insulating film on the surface of the guide member 130 alone and the thickness of the result of forming the polymer insulating film on the surface of the guide member 130 alone. It can be small compared to the sum, and can minimize the breakdown of the insulation compared to each single insulating film.

Here, the main reason for the oxide insulating film insulation breakdown may be caused by the external power supplied to the thin film heater 123 being transferred into the pinhole due to the pinhole formed in the oxide insulating film.

The main reason for the breakdown of the polymer insulating film may be due to bubble generation due to the application of liquid Pr at the time of forming the polymer insulating film, and then the dielectric breakdown may occur at the portion where the bubble was present after the polymer insulating film was solidified.

Therefore, it is preferable to compensate for the occurrence of dielectric breakdown inherent in each of the oxide insulating film or the polymer insulating film with a double insulating film of the oxide insulating film and the polymer insulating film.

The thickness of the insulating layer 122 is preferably in the range of 0.5 μm to 500 μm, particularly 0.5 μm to 200 μm, for thermal efficiency (the thickness varies depending on the material), and the dielectric breakdown voltage of the insulating film 122 (breakdown voltage) is 1,000 V or more, the leakage current (leakage current) of the insulating film 122 is 20 μA or less when the voltage is 100 V, and when the heat is generated in the thin film heater 123 (thermal cycle) 122, the desorption (peeling) is not generated from each of the guide member 130 and the thin film heater 123.

Next, the thin film heater 123 will be described. The thin film heater 123 is mounted on the insulating film 122 in the form of a thin film having a thickness of 0.05 μm to several μm (eg, 0.05 μm to 2 μm), and the metal When external power (DC power or AC power) is supplied through the pad 125, joule heating is generated by its own electrical resistance.

Here, due to the thin film characteristics of the thin film heater 123, that is, the small volume, the heat generation rate and the cooling rate may be made very fast, and the temperature generated by the self electrical resistance may exceed 500 ° C. Alternatively very fast temperature rises are possible.

The conditions of the thin film heater 123 are as follows.

First, the thin film heater 123 is capable of increasing the temperature at a faster rate than the conventional heater due to the thin film property, but due to this thin film property, the current flow rate (current flux), etc. can be very large, its own electrical / thermal Chemical resistance is required.

That is, the thin film heater 123 should have a high electrical strength (heater strength), and the self-resistance to the energy applied continuously through the metal pad 125 should be high, but maintaining the long life of the thin film heater 123 It is possible.

In addition, the thin film heater 123 is mounted on the insulating film 122, so that the insulating film 122 is not detached due to heat generation and the peeling between the guide member 130 and the insulating film 122 should not occur.

In addition, the thin film heater 123 is a device that is continuously subjected to a thermal shock, it should be such that a significant increase in the change in its resistance is not caused by the thermal shock.

In addition, the thin film heater 123 may generate heat at a high temperature while being exposed to air (oxygen), but it is necessary to prevent a significant increase in its resistance due to such oxidation.

In order to satisfy the above conditions, a thin metal having a high melting point (eg, Ta, W, Pt, Ru, Hf, Mo, Zr, Ti, etc.) may be used as the material of the thin film heater 123, Combined two-component metal alloys (e.g. TaW, etc.) are used, or two-component metal-nitride series (e.g., WN, MoN, ZrN, etc.) combined with metal-nitride is used, or metal-silicides ( Two-component metal-silicide series (for example, TaSi, WSi, etc.) combining metal-silicide is used.

In addition, the thin film heater 123 may have a thickness of several μm or less (eg, a difference in thickness occurs depending on a material, such as a range of 0.05 μm to 2 μm).

In particular, the heat capacity of the thin film heater 123 itself may be made very small so that the temperature of the thin film heater 123 may be instantaneously raised, that is, to minimize the time taken to heat itself.

That is, the heat capacity of the thin film heater 123 is expressed as a function using the thickness as a parameter, and as the thickness of the thin film heater 123 becomes thin, the value thereof decreases. On the other hand, the life of the thin film heater 123 may be shorter as the thickness becomes thinner.

Therefore, in the present invention, the optimum thickness range of the thin film heater 123 may be derived through various simulations and experiments to satisfy two conditions for instantaneously raising the temperature of the thin film heater 123 and extending the life. On the other hand, there is a slight difference depending on the material of the thin film heater 123, it turns out that it is a minute difference.

That is, the optimum thickness of the thin film heater 123 is derived based on the following equation.

(resistivity)는 박막 히터(123) 소재의 고유한 비저항값이고, Rs(sheet resistance)는 박막 히터(123)의 면 저항값이고, t(thickness of film)는 박막 히터(123)의 두께이다. 한편, 두께와 고유 비저항값은 비례 관계에 있음을 알 수 있다.here,

(resistivity) is a specific resistivity value of the thin film heater 123 material, Rs (sheet resistance) is the sheet resistance value of the thin film heater 123, t (thickness of film) is the thickness of the thin film heater 123. On the other hand, it can be seen that the thickness and the specific resistivity are in proportion.

Therefore, when the simulation using the above-described parameters as input data in consideration of the specific resistance range of the thin film heater 123 material, the optimum thickness range of the thin film heater 123 according to the characteristics of each product according to the material (eg; 0.05 μm to 2 μm, etc.).

The thin film heater 123 is formed on the insulating film 122 by the vacuum deposition method, the vacuum deposition method PVD (Sputtering, Reactive Sputtering, Co-Sputtering, Evaporation, E-beam, etc.) and CVD (LPCVD, PECVD, etc.) ) Is used.

7 to 8 are exemplary views showing various embodiments of a conductor pattern formed on a thin film heater according to the present invention. As shown in the figure, the electrical resistance is lower than the thin film heater on the thin film heater 123 and the thermal conductivity is low. The high conductor pattern 124 can be formed in various shapes, shapes and spacings.

If the thin film heater 123 in which the conductor pattern 124 is not formed is used, a temperature difference occurs between the electrode introduction portion and the center portion of the thin film heater 123 at the initial stage of power supply, so that the entire surface of the thin film heater 123 is uniform. If the temperature distribution is not achieved or overheating occurs in a part of the thin film heater 123, the film may cause fatal damage (deterioration) to the thin film heater 123 or the insulating film 122, and the life of the thin film heater may be extremely extreme. Can be shortened.

That is, in order to prevent such a phenomenon and to generate a uniform heat generation on the entire surface of the thin film heater 123 in a faster time at the initial power supply, as shown in FIGS. 7 to 8 on the thin film heater 123. It is to form a conductor pattern 124 of the shape and shape.

As such, when the conductor pattern 124 is formed on the thin film heater 123, the production yield may be improved as compared to a single thin film heater in which the conductor pattern is not formed in the thin film heater 123. This is because a single thin film heater in which a sieve pattern is not formed can solve a conventional problem leading to deterioration of the quality of the entire resistor even when a small thickness difference of a part of the entire thin film heater or damage of some thin films such as scratches.

Next, with reference to the metal pad 125, the metal pad 125 is mounted on the thin film heater 123, and serves to uniformly supply power supplied from the outside to the thin film heater 123. . In this case, the metal pad 125 may be uniformly grounded on the entire surface of the thin film heater 123 so as to have a uniform (constant) current density on all surfaces of the thin film heater 123.

In particular, the width (thickness) of the metal pad 125 may be greater than or equal to the width (thickness) of the thin film heater 123 in order to have a uniform current density in all surfaces of the thin film heater 123. .

10 to 11 are exemplary views showing various arrangement patterns of a metal pad and a thin film heater according to the present invention, and as shown in the figure, a plurality of heat generating thin film cells may be formed in the shape of the metal pad 125. It can be formed into a pattern having various positions, shapes, sizes and numbers.

The reason for forming the thin film cell is to divide the heat generating area into several parts while preventing the ground parts of the metal pad 125 and the thin film heater 123 from being powered from being destroyed due to overheating when a large amount of power is supplied at a time. In order to control the resistance value of each region.

The material forming the metal pad 125 as described above ensures stability to the temperature of the metal pad 125 when heat is generated from the thin film heater 123, prevents an increase in resistance due to oxidation, and the thin film heater. Metals such as Al, Au, W, Pt, Ag, Ta, Mo, Ti, H, Cu, etc. to prevent desorption from 123 may be used.

Finally, the protective layer 127 is mounted on the outer surfaces of the thin film heater 123 and the metal pad 125 to electrically / chemically protect the thin film heater 123 and the metal pad 125 from the external environment. As the material of the protective layer 127, SiNx, SiOx, AlOx, Polymer, Polyimide, Teflon, etc. may be used, and the thickness of the protective layer 127 is an optimal thickness to exert a heat insulating function and a protective function. And preferably in the range of about 0.1 μm to 100 μm.

The protective layer 127 may be formed in both the thin film heater 123 on which the conductor pattern 124 is formed and the thin film heater 123 in a state where the conductor pattern is not formed.

12 is a schematic view showing the specifications of the specimen for testing the heating characteristics of the heating means according to the present invention, Figure 13 is a temperature change value according to the time displacement in a state in which a constant current (50W) is applied to the specimen of FIG. The measured graph is shown, and FIG. 14 shows a graph of measuring the temperature change value according to the displacement of the amount of current applied during the time (10 seconds) specified in the specimen of FIG.

In this case, the temperature values measured through FIGS. 12 to 14 are measured by the components of the components, such as the thin film heater 123, the conductor pattern 124, the insulating film 122, the metal pad 125, and the guide member 130. It should be noted that different results may be obtained depending on resistance value, thickness, material, and the like.

As shown in FIG. 13, it can be seen that a saturation characteristic appears at 287 ° C. after a predetermined time when 50 watt power is applied.

As shown in FIG. 14, it can be seen that the surface temperature change that increases for 10 seconds according to the power change has a linear increase characteristic.

The heating means 120 according to the present invention as described above, the resistance value, thickness, material of each component such as a thin film heater, a conductor pattern, an insulating film, a metal pad, a thin film cell, a guide member and the like reflecting the design conditions of the product Different applications are applied to reduce surface temperature arrival time and power consumption according to product characteristics, so that the optimum product can be produced.

Referring to the operation of the electrophotographic image forming apparatus according to the present invention having the configuration as described above is as follows.

First, the power supply is turned on to the office apparatus to which the image forming apparatus of the present invention is applied.

The power supply is input to the metal pad 125 of the heat generating means 120, and is uniformly supplied to the entire area of the thin film heater 123 again to self-heating.

The high temperature heat due to the heat of the thin film heater 123 is transferred to the guide member 130 through the insulating film 122.

At this time, the heated guide member 130 is to heat the thermosetting resin and the metal tube forming the sleeve 140 surrounding the outer surface, by the preheating wing 133 formed at one end of the guide member 130 the sleeve ( The fixing process is performed in a state in which 140 is sufficiently preheated. Here, the preheating performance is further improved when the sleeve 140 is formed of a metal tube.

The sleeve 140 having a sufficient preheating area as described above passes through the lower end of the guide member 130 in conjunction with the rotation of the pressure roller 110 which is grounded.

At this time, the recording material P is supplied and transferred between the sleeve 140 and the pressure roller 110, and heated by the sleeve 140 to form an image in a state where the toner T is passionately attached to the upper surface. Ejected from the device.

As described above, the thin film heater 123 generates rapid heat even with a low power external power source, which has a characteristic of rapidly heating to 120 degrees Celsius or more in 20 seconds when the 500W power is applied. As a result, the waiting time required for preheating is shortened.

As mentioned above, although the present invention has been described by way of examples, the embodiments of the present invention are merely examples and should not be construed as limiting the scope of the present invention. Those skilled in the art to which the present invention pertains may modify or alter the present invention in various forms within the principles and scope described in the claims herein.

In the present invention as described above, the heating means including the thin film heater is formed on the upper surface of the guide member, and the lower surface shape of the guide member is curved while utilizing the entire surface of the guide member as a heating plate by using a metallic material having high thermal conductivity. By forming the true pressurized curved portion, there is an effect that it is possible to ensure a more expanded heat fixing area than the conventional ceramic heater.

In addition, the present invention by forming the preheating wing portion of the guide member, the heat fixing operation is performed in a state that the sleeve is sufficiently preheated has the effect that the output speed of the electrophotographic is increased.

In addition, the present invention is a structure in which the heat generating means is formed on the upper surface of the guide member, there is an effect that the life is extended as it is not rubbed with the sleeve without being subjected to the pressing force by the pressure roller.

In addition, the present invention has a convenient operation is shortened the standby time due to the characteristics of high-speed heat using a thin film heater.

In addition, the present invention has an effect of improving the thermal efficiency by allowing the heat generated by the heat generating means to be conducted through the excellent metallic guide member and the metal tube through the thermal conductivity, thereby minimizing the temperature difference between the passage area and the non-passing area of the recording material. .

Claims (14)

A pressure roller 110 installed to actuate pressure in an upward direction; A guide member 130 installed on the pressure roller 110 to form a pressurized curved portion 131 to be compressed; A heat generating means (120) stacked on the pressing curved portion (131) of the guide member (130) to provide heat generation using the thin film heater (123); And The sleeve 140 is mounted in a form surrounding the outer surface of the guide member 130 to receive heat and to transfer and heat-settle the recording material that is driven by friction driving in a state facing the pressure roller 110. ; Electrophotographic image forming apparatus comprising a. The method of claim 1, The guide member 130 has a predetermined width bottom to form a pressing curved portion 131, and to form a preheating wing portion 133 extending to at least one end of the left and right ends of the pressing curved portion 131. An electrophotographic image forming apparatus, characterized in that the sleeve (140) is preheated before entering the pressing curved portion (131). The method of claim 2, The guide member (130) is an electrophotographic image forming apparatus, characterized in that it is produced using at least one of aluminum, stainless steel or a conductive metal containing an alloy of aluminum and stainless steel excellent in thermal conductivity. The method of claim 1, The sleeve 140 is an electrophotographic image forming apparatus, characterized in that the thermosetting resin film layer 141 is formed on the outer diameter of the thin metal tube 143 having excellent thermal conductivity. The method according to any one of claims 1 to 4, The heating means 120, A guide member 130 made of a non-conductive material; A thin film heater 123 mounted on the back surface of the guide member 130 in a form of a thin film and receiving power from the outside to instantaneously generate high temperature by instantaneous heating according to its own electrical resistance; And A metal pad 125 having electrical bonding to the thin film heater 123 and having a specific pattern such that power supplied from the outside may be uniformly applied to the entire surface of the thin film heater 123; Electrophotographic image forming apparatus comprising a. The method of claim 5, The heating means 120, A guide member 130 made of a conductive material; An insulating film 122 coated on the back surface of the guide member 130 with a predetermined thickness to provide electrical insulation properties and excellent thermal conductivity properties; A thin film heater 123 mounted in the form of a thin film on the lower portion of the insulating film 122 and receiving power from the outside to instantaneously generate high temperature by instantaneous heating according to its own electrical resistance; And A metal pad 125 having electrical connection to the thin film heater 123 and having a specific pattern such that power supplied from the outside may be uniformly applied to the entire surface of the thin film heater 123; Electrophotographic image forming apparatus comprising a. The method of claim 6, By forming a conductor pattern 124 for current to flow on the thin film heater 123, the generated heat is uniformly supplied to the entire surface of the thin film heater 123, characterized in that the heating characteristics are stabilized An electrophotographic image forming apparatus. The method of claim 6, And the metal pad (125) forms a pattern to form a plurality of heat generating thin film cells. The method of claim 6, The thin film heater 123 is a combination of two-component metal-nitride or metal-silicide in which a single metal or a two-component metal alloy or a metal-nitride is combined. An electrophotographic image forming apparatus comprising any one of a component metal silicide or a thick film conductive paste. The method of claim 6, The metal pad 125 is set so that its width is greater than or equal to the width of the thin film heater so that current density can be uniformly supplied to the thin film heater 123, and is stable to temperature during heat generation, and according to oxidation An electrophotographic image forming apparatus comprising any one of Al or Au or W or Pt or Ag or Ta or Mo or Ti to prevent resistance increase and physical peeling. The method of claim 6, The insulating film 122 may be formed by oxidizing the surface of the guide member 130 with an arc or a polymer insulating film formed by coating a polymer on the surface of the guide member 130, or the oxide insulating film and the polymer insulating film on the surface of the guide member. An electrophotographic image forming apparatus, characterized in that any one of the formed double insulating films. The method of claim 11, And said insulating film (122) has an insulation breakdown voltage of 1000 V or more and a leakage current of 20 mA or less when 100 V voltage is applied. The method of claim 11, The oxide insulating film is any one of metal oxides including aluminum oxide or beryllium oxide or titanium oxide, and the polymer of the polymer insulating film is polyimide or polyamide or teflon or paint. Or silver-ston or tefzel-s or epoxy or rubber. The method of claim 6, An electrophotographic image forming apparatus, wherein a protective layer 127 is coated to a predetermined thickness so that the metal pad 125 and the thin film heater 123 are protected from an external environment.

Images