JP2005148350A - Induction heating fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating fixing device which attains more energy saving. <P>SOLUTION: In the induction heating fixing device, a sliding member has a plurality of sliding surfaces having heat generation areas induction-heating by applying an AC current to an exciting coil and having different heat generation width in a rotary shaft direction, and a plurality of sliding surfaces provided on the sliding member are switched to be opposed to the exciting coil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an induction heating fixing device used in an image forming apparatus such as a copying machine, a printer, and a fax machine, and more particularly, to an induction heating fixing device including a sliding member having a plurality of sliding surfaces having heat generation regions having different heat generation widths. .

  Conventionally, as a fixing device used in an image forming apparatus such as a copying machine, a printer, a FAX, etc., a software having a rubber layer on a mandrel as a highly stable and technically stable material and using a halogen lamp as a heating element The heat roller fixing system is widely used in full color machines from low speed machines to high speed machines. In this type of heat roller fixing method, there is known a heat roller fixing device in which two lamps having different heat generation regions are provided in a halogen lamp, and the temperature distribution in the longitudinal direction of the fixing roller causing hot offset is substantially uniform. (See Patent Document 1).

  In this heat roller fixing method, a method of lowering the temperature by a cooling fan has been conventionally used in response to an increase in end temperature when a small-size transfer material is passed. However, now that energy conservation is required, it is difficult to accept the idea of cooling the warmed items. In order to cope with the passing of the small-size transfer material, there is a method of winding a coil of a halogen lamp in parallel. However, it is difficult to equalize the temperature in the axial direction. In addition, since two or more coils are required, there is a problem in terms of cost. Therefore, it has been a problem to change the heat generation distribution without increasing the number of coils.

  Further, in the fixing device using the endless belt member, the resistance heating element portion of the heating panel including the curved surface portion for slidingly contacting the back side of the fixing belt is provided on the back side of the curved surface portion, A first heating element, which is a strip-like resistance heating element that is bent back and forth in a direction perpendicular to the direction of movement of the fixing belt, and has a heating width corresponding to a narrow recording sheet, and the first heating element And a belt-type fixing device including a second heating element having a heating width for accommodating a wide recording sheet is known (see Patent Document 2).

  On the other hand, in a conventional soft heat roller fixing type fixing device, when a transfer material or toner is heated, it is necessary to heat a fixing roller (heating member) having a low thermal conductivity and a large heat capacity. It is bad and disadvantageous in terms of energy saving, and there is a problem that it takes time to warm the fixing device during printing and the warm-up time (WUT) becomes long.

As a fixing device for solving these problems, an induction heating fixing device for quick start fixing capable of instantaneous heating using a roller-shaped rotating member for electromagnetic induction fixing (magnetic fixing roller) having an exciting coil as a heating member. Is known (see Patent Document 3).
JP 2002-268421 A JP 2003-287970 A JP 2002-49260 A

  However, in the induction heating fixing device adopting the induction heating method as described above for the fixing device, further energy saving becomes a problem, and in the belt fixing method using the resistance heating element and the belt fixing device. Since heat is transferred to the fixing belt by contact with a cylindrical surface, efficient heat transfer with good response is possible, but contact with the heat generating member causes a problem in safety.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an induction heating fixing device that solves the above-described problems, further saves energy, and improves safety.

  The object is to provide an endless belt, a sliding member provided on the inner surface of the endless belt, a roller member that supports the inner surface of the endless belt, and a pressure member that presses against the outer peripheral surface of the endless belt to form a nip. And an exciting coil facing the sliding member via the endless belt, and by passing an alternating current through the exciting coil, the sliding member generates heat to heat the endless belt, and the endless belt and the In the induction heating fixing apparatus that fixes a toner image by sandwiching and transferring a transfer material with a pressure member, the sliding member has a plurality of heat generation regions having different heat generation widths that generate induction heat by passing an alternating current through the excitation coil. This is achieved by an induction heating fixing device having a sliding surface in the rotation axis direction and switching a plurality of sliding surfaces provided on the sliding member so as to face the exciting coil.

  By adopting the above-described configuration, the present invention aims to provide an induction heating fixing device that eliminates the need for a cooling fan at the end, further saves energy, and improves safety.

  According to the present invention, the cooling fan at the end is not required, and in the heat roller fixing method using a halogen lamp, the entire roller member is heated, whereas in the present invention, the heat generation of each heat generating surface of the sliding member is performed. Since it is only necessary to locally heat the region, it is possible to provide an induction heating fixing device with further energy savings. Further, by adopting an induction heating fixing method, the fixing belt and the opposing member (sliding member) can be provided. Since both can generate heat and can be heated without contact, it is possible to provide an induction heating fixing device that is advantageous in terms of energy saving and safety.

  Embodiments of the present invention will be described below. The description in this column does not limit the technical scope of the claims or the meaning of terms. In addition, the following assertive description in the embodiment of the present invention shows the best mode, and does not limit the meaning or technical scope of the terms of the present invention.

  (1) An image forming apparatus using the induction heating fixing apparatus according to the present invention will be described below with reference to FIG.

  The image forming apparatus according to the present invention includes an exposure device 12 as an image exposure unit that performs image exposure on a photosensitive drum 10 as an image carrier in accordance with data after image processing, a photosensitive drum 10 around the photosensitive drum 10, and a charging unit. Image forming means such as a belt electrode 11, a developing device 13 as a developing means comprising a magnetic brush type developing device having a developer carrying member, a transfer separation electrode 14 as a transfer separation means, a cleaning device 19 as a cleaning means, And an induction heating fixing device 17 for fusing and fixing the toner image on the transfer material (on the recording paper P).

  Image data read by an image reading device (not shown) and stored in a memory is called up according to image formation, and image exposure is performed on the photosensitive drum 10 by the exposure device 12 using, for example, a laser optical system according to the image data. Is done.

  Prior to the image exposure, the photosensitive drum 10 rotated in the clockwise direction indicated by the arrow is given a predetermined surface potential by the corona discharge action of the strip electrode 11, but the potential of the latent image portion by the image exposure is exposed. As a result, an electrostatic latent image corresponding to the image data is formed on the photosensitive drum 10.

  The electrostatic latent image is charged with the same polarity as the charging polarity (in this embodiment, the toner polarity used for development is a negative polarity) by a developing roller (not indicated) as a developer carrier provided in the developing unit 13. Using a toner (toner powder) having a negative polarity), the toner image is reversely developed to obtain a visualized toner image. Further, as shown in the figure, the developing unit 13 is provided with a developing urethane sheet 13b on the upstream side in the rotation direction of the photosensitive drum 10 with respect to the developing position.

  On the other hand, before the leading end of the toner image on the photosensitive drum 10 reaches the transfer area of the transfer separation pole 14, the recording paper P as a transfer material in the paper feed tray (not shown) is fed by a feed roller (not shown). ) To reach the registration roller 16 and the tip is regulated.

  The recording paper P is transferred by a registration roller 16 that starts rotating in synchronization with a toner image, that is, an image area on the photosensitive drum 10, so that a transfer area of a transfer separation pole 14 that is a charging means and a transfer means. It is conveyed toward.

  In the transfer area, the toner image on the photosensitive drum 10 is transferred onto the recording paper P by the transfer corona discharge of the transfer separation electrode 14, and the recording paper P is exposed to the static electricity by the separation corona discharge of the transfer separation electrode 14. Separated from body drum 10.

  The recording paper P onto which the toner image has been transferred is formed by a sliding member SHB having a plurality of sliding surfaces A, B, and C as heated members to be heated by an exciting coil LCLa as a heating member of the induction heating fixing device 17. Toner that forms a toner image by pressurization and heating at a nip portion N formed between a tension roller 17c provided across the fixing belt 27 to be heated and a pressure roller 47a as a pressure member. The powder (toner) is melted and fixed on the recording paper P, and the recording paper P is discharged outside the apparatus. An excitation coil LCLa is disposed outside the sliding member SHB as a heating member that heats the heat generation areas a, b, and c of the sliding member SHB by an induced current. A coil bobbin CLB as a coil support member is provided outside the excitation coil LCLa. The exciting coil LCLa is attached to the coil bobbin CLB.

  The transfer residual toner remaining on the peripheral surface of the photosensitive drum 10 after the transfer is cleaned by a cleaning device 19 including, for example, a cleaning roller 191c using a conductive brush and a blade unit 190 including a cleaning blade 191a as a cleaning member. Then, the toner is collected in the cleaning device 19 and is collected in a toner collection container (not shown) by a conveying screw 191h. The blade unit 190 is provided with a cleaning blade 191b as a replacement cleaning member.

  After the transfer residual toner on the photosensitive drum 10 is collected by the cleaning device 19, the image forming apparatus enters the next image forming cycle.

  In the description of the image forming apparatus, monochrome image formation has been described, but a case of forming a color image is also included in the present invention.

  (2) An induction heating fixing device having a sliding member according to the present invention will be described below with reference to FIGS. 2 is a schematic sectional view of an induction heating fixing apparatus having a sliding member according to the present invention, FIG. 3 is a perspective view of the sliding member of FIG. 2, and FIG. 4 is a sliding member of FIG. It is a figure which shows the heat_generation | fever distribution of the heat_generation | fever area | region of the some sliding surface provided in FIG.

  As shown in FIG. 2, the induction heating fixing device 17 is provided outside the sliding member SHB, and is heated by the exciting coil LCLa as a heating member that heats the sliding member SHB by an induction current, and the exciting coil LCLa. A sliding member SHB as a member to be heated; a fixing belt 27 that stretches the sliding member SHB at one end (excitation coil LCLa side), and stretches the stretching roller 17c at the other end; A pressure roller 47a as a pressure member provided with the fixing belt 27 interposed therebetween, and a coil bobbin CLB as a coil support member for attaching and supporting the excitation coil LCLa outside the excitation coil LCLa. The exciting coil LCLa is composed of a coil wire CLa made of a litz wire LPt covered with a surface tube CBa.

  Between a tension roller 17c provided across a fixing belt 27 heated by a sliding member SHB as a heated member heated by an exciting coil LCLa as a heating member, and a pressure roller 47a as a pressure member The toner powder (toner) for forming the toner image is melted and fixed on the recording paper P by pressurization and heating at the nip portion N formed by the above.

  The sliding member SHB according to the present invention has a plurality of sliding surfaces in the direction of the rotation axis, each having a heat generating region having different heat generation widths that generate induction heat by passing an alternating current through the exciting coil, and is provided on the sliding member. The sliding surface consisting of a plurality of arc portions can be switched to face the exciting coil.

  The sliding member SHB uses a plate material such as nickel, iron, and aluminum, for example, and is divided into sliding surfaces A, B, and C having three arc portions in the circumferential direction as shown in FIG. In the direction, there are different heat generating areas a, b, c of the three sliding surfaces A, B, C. The sliding surface A has a heat generating area a corresponding to, for example, the A-3 vertical feed size, the sliding surface B has a heat generating area b corresponding to, for example, the B-5 vertical feeding size, and the sliding surface C has, for example, It has a heat generation area c corresponding to the postcard size. The sliding surfaces A, B, and C are rotated according to the size of each transfer material, and are switched to face the excitation coil LCLa. Further, the cross section of the sliding member SHB (surface perpendicular to the rotational axis direction of the sliding member) has a substantially circular shape, and the substantially circular shape is composed of two or more arc portions in the circumferential direction as described above. It is divided into sliding surfaces. Further, the heat generating areas a, b, and c of the circular sliding surfaces A, B, and C are partitioned by an insulating member made of a resin member such as polyimide or polyamide, and are integrally formed. Yes. Note that the shape of the sliding member is not necessarily formed by a plurality of arc portions, and may be an integrated cylindrical portion. Further, the sliding member is not necessarily cylindrical, and may be triangular or rotary.

  The tension roller 17c is configured as a soft roller made of a foam of silicon rubber having a rubber hardness of about 10Hs to 40Hs (JIS, A rubber hardness), for example.

  As the fixing belt 27 which is an endless belt, for example, a metal belt using a nickel electroformed belt having an inner diameter of about 70 to 120 mm and a thickness of about 20 to 80 μm, a polyimide or polyamide having a thickness of about 40 to 150 μm, and the like. The outer surface (outer peripheral surface) of the heat-resistant resin belt used is coated with heat-resistant silicon rubber having a thickness of about 100 to 300 μm, and PFA (perfluorocarbon) having a thickness of about 30 to 50 μm on the surface as a release layer. Alkoxy) coated or tube-coated is used.

  Further, a pressure roller 47a as a pressure member provided to face the stretching roller 17c with the fixing belt 27 interposed therebetween includes a cored bar 471a made of a solid round bar made of, for example, stainless steel, and the cored bar. A rubber roller layer 472b formed on the outer periphery of 471a and made of, for example, a silicone rubber foam having a rubber hardness of about 10Hs to 40Hs (JIS, A rubber hardness), and PFA (perfluoroalkoxy) provided on the surface of the rubber roller layer 472b It is formed as a soft roller comprising a release layer 472c covering the tube. As the metal core 471a of the pressure roller 47a, for example, a hollow (pipe-shaped) round bar using a stainless pipe material may be used. The rubber roller layer 472b may have a rubber hardness of about 40Hs to 80Hs (JIS, A rubber hardness), and the pressure roller 47a may be a hard roller.

  As the exciting coil LCLa, for example, a laminated steel plate such as a ferrite core or permalloy is used, and is attached to a coil bobbin CLB having a radiation fin HFN as a coil support member.

  An alternating magnetic field is formed in any one of the heat generation regions a, b, and c of the sliding member SHB by magnetic lines (magnetic flux) generated by the induction current of the coil wire CLa of the exciting coil LCLa, and the sliding member SHB is heated. . The sliding member SHB is heated by an alternating magnetic field formed inside by magnetic lines (magnetic flux) emitted from the coil wire material CLa of the exciting coil LCLa made of the litz wire LPt, and a roll-like heated member capable of rapid heating is formed. . In other words, the member to be heated used in the induction heating fixing device 17 of the present invention is one of the heat generation regions a, b, and c of the sliding member SHB by passing a current through the exciting coil LCLa serving as the heating member and by the lines of magnetic force (magnetic flux). An alternating magnetic field of about 0.5 to 50 kHz is formed in one, and the sliding member is caused by an eddy current (inductive current) in any one of the heat generation regions a, b, and c of the sliding member SHB generated by the alternating magnetic field. SHB is heated. For example, heating is performed on the sliding surface A of the sliding member SHB having a heating width of the curve (a) shown in FIG. 4 by the heat generation area a of the sliding member SHB (the transfer material A-3 vertical feed size described above). Width support). Further, for example, heating is performed on the sliding surface B of the sliding member SHB having a heating width of the curve (b) shown in FIG. 4 by the heat generation area b of the sliding member SHB (the transfer material B-5 longitudinal feeding described above). Size width correspondence). Further, for example, heating is performed on the sliding surface C of the sliding member SHB having the heating width of the curve (c) shown in FIG. 4 by the heating area c of the sliding member SHB (corresponding to the postcard size width described above).

  Further, the fixing belt 27 is rotated by rotation of a drive motor (not shown), and the pressure roller 47 a is driven to rotate by the fixing belt 27. The fixing belt 27 is rotated while sliding on the sliding member SHB.

  A wide nip portion having a width of about 5 to 25 mm formed between a tension roller 17c configured as an upper hard roller and a pressure roller 47a also configured as a soft roller with the fixing belt 27 interposed therebetween. By sandwiching the recording paper P with N and applying heat and pressure, the toner image (or color toner image) on the recording paper P is satisfactorily fixed at the nip portion N.

  TS1 is a temperature detecting element which is a temperature detecting means using, for example, a contact type thermistor for controlling the temperature attached to the sliding member SHB with the fixing belt 27 interposed therebetween, and TS2 is attached to the pressure roller 47a. For example, a temperature detecting element using a contact type thermistor for performing temperature control. As the temperature detection elements TS1 and TS2, in addition to the contact type, it is also possible to use a non-contact type.

According to the present invention, in the induction heating fixing device 17, the width of the exciting coil LCLa with respect to the moving direction of the fixing belt 27 is Lc, and the heating areas a, b, c of the sliding surfaces A, BC facing the exciting coil LCLa are set. When the width is Lh,
0.8Lh <Lc <1.2Lh
It is preferable to set as follows, and thereby more energy saving effect is exhibited.

  According to the above, in the heat roller fixing method using a halogen lamp, the entire roller member is heated, but in the present invention, local heating of the heat generating area of each heat generating surface of the sliding member is sufficient, so that an energy saving effect is exhibited. .

  As described above, the configuration as in the present invention eliminates the need for a cooling fan at the end, and provides an induction heating fixing device that achieves further energy saving, and further adopts an induction heating fixing method. As a result, both the fixing belt and the opposing member (sliding member) can generate heat and can be heated in a non-contact manner, so that an induction heating fixing device advantageous in terms of energy saving and safety can be obtained. .

1 is a schematic cross-sectional configuration diagram of an image forming apparatus in which an induction heating fixing device according to the present invention is used. 1 is a schematic sectional view of an induction heating fixing device having a sliding member according to the present invention. It is a perspective view of the sliding member of FIG. It is a figure which shows the heat_generation | fever distribution of the heat_generation | fever area | region of the some sliding surface provided in the sliding member of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Photosensitive drum 11 Band electrode 12 Exposure apparatus 13 Developer 14 Transfer separation pole 17 Induction heating fixing apparatus 17a Heating roller 17c Stretching roller 27 Fixing belt 47a Pressure roller A, B, C Sliding surface a, b, c Heat generation Area CLB Coil bobbin LCLa Exciting coil N Nip part SHB Sliding member P Recording paper

Claims (4)

An endless belt, a sliding member provided on the inner surface of the endless belt, a roller member that supports the inner surface of the endless belt, a pressure member that presses against an outer peripheral surface of the endless belt to form a nip, and the endless belt An excitation coil facing the sliding member via a belt, and heating the endless belt by causing the sliding member to generate heat by passing an alternating current through the excitation coil, and the endless belt, the pressure member, In the induction heating fixing device for fixing the toner image by nipping and conveying the transfer material at
The sliding member has a plurality of sliding surfaces in the rotation axis direction having heat generation regions having different heat generation widths that generate induction heat by passing an alternating current through the exciting coil, and the plurality of sliding members provided on the sliding member. An induction heating fixing device characterized in that the surface can be switched to face the exciting coil. The induction heating fixing device according to claim 1, wherein the sliding member has a circular cross section, and the circular shape is divided into a sliding surface including two or more arc portions in a circumferential direction. . The induction heating fixing device according to claim 2, wherein the heat generation area of the circular sliding surface divided into two or more in the circumferential direction is partitioned by an insulating member. When the width of the exciting coil with respect to the moving direction of the endless belt is Lc and the width of the heat generation area of the sliding surface facing the exciting coil is Lh,
0.8Lh <Lc <1.2Lh
The induction heating fixing device according to any one of claims 1 to 3, wherein

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