JP2004020717A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which is provided with a heating roller simple in structure and capable of easily changing a heating width according to the printing width of a recording medium and always uniformly heating the recording medium over the heating width and is reduced in electric power consumption. <P>SOLUTION: A first filament continuum 101 and second filament continuum 102 of a halogen lamp heater 100 built in the heating roller 6 are respectively formed by serially connecting a plurality of filaments 120 in a manner as to vary the distributions of the calorific values in an axial direction. When the printing width of the recording medium is narrower than a preset width, only the first filament continuum 101 is lighted to heat only the prescribed width of the heating roller. The heating width of the heating roller 6 is changed over according to the printing width of the recording medium in such a manner, by which the unnecessary heating is suppressed and the electric power consumption is reduced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus provided with a heating roller using a halogen heater lamp as a heating source.
[0002]
[Prior art]
2. Description of the Related Art Generally, an electrophotographic image forming apparatus forms an image on the surface of printing paper as a recording medium through the following steps. First, after the surface of the photosensitive drum is charged with static electricity, the surface of the photosensitive drum is irradiated with a laser beam or the like to partially discharge the static electricity and form a pattern into characters or images. Next, toner charged with static electricity having the same polarity as the static electricity charged on the photosensitive drum is adsorbed on the surface of the photosensitive drum. As a result, an aggregate of toner forming a desired character or image pattern is formed on the surface of the photosensitive drum. Then, the toner aggregate is transferred to the surface of the printing paper, and the transfer surface is sandwiched by a heating roller and the opposite surface is sandwiched by a pressing roller, and is heated and fixed.
[0003]
The heating roller of such an image forming apparatus has a built-in heater serving as a heating source, and maintains a temperature range necessary for fixing by heating the heater. As this heater, a halogen heater lamp may be used. Since the halogen heater lamp has a high heat output, it has advantages that a fixing temperature range (150 ° C. to 200 ° C.) can be easily maintained and a warm-up time can be shortened. As shown in FIG. 5A, in a conventional halogen heater lamp 100, a filament continuous body 111 in which a plurality of filaments 120 extending in series along a tube axis are connected in series in a straight tubular lamp tube 110 made of quartz glass. It is arranged. This is shown by an equivalent circuit in FIG.
[0004]
In FIG. 5B, since each filament is a kind of resistance heating element, the symbol of the resistor is shown.
[0005]
Both ends of the filament continuous body 111 are held by connecting portions 105 provided at both ends of the lamp tube 110, and electric power is supplied through the external leads 103 that are connected to the connecting portions 105. Further, the filament continuous body 111 and the connection portions 105 at both ends thereof are hermetically sealed in the lamp tube 110, and are filled with argon gas or the like. The halogen heater lamp 100 obtains a heating value distribution as shown in FIG. 5C by appropriately adjusting the arrangement pattern of the plurality of filaments 120 connected in series.
[0006]
[Problems to be solved by the invention]
However, the conventional image forming apparatus has the following problems to be solved. When a halogen heater lamp incorporated in a heating roller in a conventional image forming apparatus supplies electric power and performs heating, electric power is supplied to all filaments in a lamp tube to heat the filament. Thereby, the heating roller is always heated at the full width, but when the width of the printing paper is smaller than the width of the heating roller, a portion corresponding to the heating roller outside the width of the printing paper is not used. Useless power is consumed.
[0007]
As a method for solving this problem, as shown in FIG. 6, an image forming apparatus having a structure in which halogen heater lamps 100a and 100b having different heating value distributions in the tube axis direction are arranged in the heating roller 6 has been devised. . However, when a plurality of halogen heater lamps are provided as described above, it is difficult to position the heating rollers uniformly in order to uniformly heat the required width of the heating roller. Further, by incorporating a plurality of halogen heater lamps, it becomes difficult to process the heating roller. Further, the number of halogen lamps increases, so that the material cost increases.
[0008]
Other techniques for reducing the power consumption of the image forming apparatus are described in (1) Japanese Patent Application Laid-Open No. 5-11659, (2) Japanese Patent Application Laid-Open No. 2002-40849, and (3) Japanese Patent Application Laid-Open No. 2002-31975. It has been disclosed.
[0009]
In the technology of (1), sliding electrodes are provided at both ends of a straight tubular resistance heater and at positions on both sides which are separated from the center by a predetermined distance in the axial direction, and the sliding electrodes are selected according to the width of the printing paper. By doing so, the resistor built in the heater is heated only for a predetermined width (paper printing width).
[0010]
The technique of (2) is to connect two identical carbon heater lamps in series or in parallel according to the power supply voltage so that the carbon heater lamps can operate normally even if power supplies of different voltages are used. At the same time, the individual carbon heater lamps are independently turned on and off to perform precise temperature control of the heating roller corresponding to the operation mode.
[0011]
Further, the technique of (3) has a heating element in which the amount of heat generated in the axial direction of the carbon heater lamp is different between the end portion and the central portion, so that a predetermined temperature distribution is obtained in the axial direction at a required local position of the heating roller. Thus, the fixing process is reliably performed regardless of the width of the printing paper. In addition, this technology controls a heating value distribution in the axial direction of the entire heating roller by arranging and combining the carbon heater lamps with a plurality of carbon heater lamps having different temperature distributions built in the heating roller. Things.
[0012]
These technologies each disclose a power saving method of a heating source built in a heating roller. The technology (1) mainly uses a resistance heater, and the technologies (2) and (3) use a carbon heater. There is no disclosure of a technique relating to a power saving method of a heating source using a halogen heater lamp.
[0013]
An object of the present invention is to provide a heating roller having a simple structure that can easily change a heating range in accordance with a printing direction width of a recording medium to be used and can constantly uniformly heat the heating range. An object of the present invention is to provide a power saving image forming apparatus.
[0014]
[Means for Solving the Problems]
In order to solve the above-described problems, an image forming apparatus according to the present invention includes a heating roller that incorporates a heating source including a halogen heater lamp and heats and fixes a toner image formed on a recording medium surface. First and second filament continuous bodies having filaments connected in series are arranged in a lamp tube in parallel with the axial direction of the lamp tube to form a halogen heater lamp. Each of the first and second filament continuous bodies is provided with a plurality of filaments so that the heat generation distribution in the axial direction differs from each other. The image forming apparatus further includes a heating control unit that selects at least one of the first and second filament continuum constituting the halogen heater lamp and generates heat.
[0015]
In this configuration, two filament continuums each having a different heating value distribution in the axial direction are disposed in parallel inside one halogen heater lamp, and either one or both of the two filaments are controlled by the heating control means. By heating the filament continuous body, a heating source having a plurality of different calorific value distributions is configured. Thereby, the heating roller is heated in a plurality of widths.
[0016]
Further, the heating roller of the image forming apparatus according to the present invention is configured such that the plane including the axes of the first and second filament continuities arranged in parallel and the conveyance path of the recording medium are parallel to each other. First, a halogen heater lamp provided with a second filament continuous body is incorporated.
[0017]
In this configuration, since the distance from each of the first and second filament continuum to the point on the recording medium transport path where the toner on the surface of the recording medium is heated and fixed by the heating roller is equal, the filament continuum to be heated is Is changed, the efficiency of heat transfer to the heat fixing point does not change.
[0018]
In the heating roller of the image forming apparatus according to the present invention, the first filament continuum and the second filament continuity are such that a plurality of filaments connected in series do not overlap in the axial direction of the filament continuum. Placed in
[0019]
In this configuration, the first filament continuum and the second filament continuum have different heating ranges in the axial direction, and are heat-fixed at different widths. Here, for example, the width that can be heated by the first filament is set in advance with reference to the widths of a plurality of types of recording media to be printed, so that if the printing width is smaller than the set width, only the first filament is used. When the printing width is wider than the set width, power is supplied to both filament continuities to heat the filament.
[0020]
Further, the heating roller of the image forming apparatus according to the present invention is arranged such that a plurality of filaments of the first filament continuum are arranged over a predetermined width in both directions from the axial center of the filament continuity. A halogen heater lamp is used in which a plurality of filaments of the body are arranged from both ends at a predetermined distance from the center in the axial direction of the filament continuous body.
[0021]
In this configuration, the reference position in the printing width direction of the recording body is located at the center in the width direction, and the printing width is smaller than the width of the first filament continuous body where a plurality of filaments are arranged in the preset first filament continuous body. When printing, power is supplied only to the first filament continuum to heat only a predetermined width including the center of the heating roller. When printing on a recording medium whose recording width is wider than the preset width, power is supplied to both the first and second filament continuous bodies to heat the entire heating roller.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
An image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a main part of the configuration of an image forming apparatus according to the present invention.
2A is an external perspective view of the halogen heater lamp, FIG. 2B is an equivalent circuit diagram thereof, and FIG. 2C is a calorific value distribution diagram thereof.
[0023]
The image forming apparatus includes a transfer unit that transfers an image pattern formed by the toner 40 onto the printing paper 30 that is a recording medium, and a fixing unit that fixes the transferred toner 40. The transfer unit includes a photosensitive drum 1 on which an image pattern is formed by static electricity, a charging roller 2 for charging the surface of the photosensitive drum 1 with static electricity, and a developing syringe for attaching toner 40 to the image pattern on the surface of the photosensitive drum 1. 3, a cartridge 4 for supplying the toner 40 to the developing syringe 3, a transfer roller 5 for sandwiching the printing paper 30 with the photosensitive drum 1 and transferring the toner 40 to the surface of the printing paper 30, The cleaning unit 8 removes the toner 40 remaining on the surface. The fixing unit incorporates a halogen heater lamp 100 as a heating source, and is provided with a heating roller 6 disposed so as to be in contact with the surface 31 of the printing paper 30 to which the unfixed toner 40 adheres, and a heating roller 6 with the printing paper 30 interposed therebetween. And a pressure roller 7 disposed at a position facing the pressure roller 7. By heating and pressurizing the printing paper 30 with the heating roller 6 and the pressing roller 7, the toner 40 attached to the surface 31 of the printing paper 30 is fixed.
[0024]
The heating roller 6 includes a cylindrical body 61 made of a metal or an alloy having a high thermal conductivity and a coating layer 62 made of a fluororesin formed on the surface thereof. Similarly, the pressure roller 7 includes a body 71 and a coating layer 72. The material of the body 71 of the pressure roller 7 is not particularly limited, and generally a metal or the like is used, and the material of the coating layer 72 is an elastic body such as soft rubber or sponge rubber.
[0025]
Inside the heating roller 6, a halogen heater lamp 100 having a straight tubular shape and a cross-sectional eyeglass shape as shown in FIG. 2A is arranged such that the central axis of the heating roller 6 and the central axis of the halogen heater lamp 100 coincide with each other. It is arranged. By turning on and off the halogen heater lamp 100, the heating roller 6 is heated and cooled, so that the surface of the heating roller 6 is adjusted to a predetermined temperature. The adjustment of the heating temperature is performed by a heating control unit described later.
[0026]
The halogen heater lamp 100 is configured to supply electric power from outside to a straight tubular lamp tube 110 having a glasses-shaped cross section, first and second filament continuum bodies 101 and 102 disposed therein, and filament continuum bodies 101 and 102. It comprises external leads 103 and 104 to be supplied, and a connecting portion 105 for connecting the external leads 103 and 104 and the filament continuous bodies 101 and 102. The filament continuous bodies 101 and 102 are each formed by connecting a plurality of filaments 120 in series with an internal lead 121, and are arranged so that the axial direction of the filament continuous bodies 101 and 102 and the tube axis direction of the lamp tube 110 match. ing. At both ends of the first and second filament continuous bodies 101 and 102, connection portions 105 made of molybdenum foil or the like for connecting the internal leads 121 and the external leads 103 and 104 are provided, respectively. The lamp tube 110 is sealed on the side of the leads 103 and 104, and an inert gas such as an argon gas is sealed therein. Further, the halogen heater lamp 100 is arranged in the heating roller 6 such that a plane including the axes of the two continuous filaments 101 and 102 enclosed as shown in FIG. Is established. As a result, the distance between the two filament continuous bodies 101 and 102 is reduced from the point where the heating roller 6 and the pressure roller 7 heat the printing paper 30 to fix the toner (hereinafter, referred to as “heating fixing point”). Since they match, the thermal conductivity from each filament continuous body 101, 102 to the heat fixing point can be made uniform, and thermal design becomes easy.
[0027]
The first filament continuum 101 has a plurality of filaments 120 disposed within a predetermined width L (central portion) from the center in the axial direction to both ends, and filaments are disposed in other portions (both ends). Has not been arranged. On the other hand, the second filament continuous body 102 does not have a filament disposed at the center, but has a plurality of filaments 120 disposed at both ends. This is represented by an equivalent circuit in FIG. In FIG. 2B, since each filament is a kind of resistance heating element, the symbol of the resistor is shown. Here, as shown in FIG. 2 (c), when only the first filament continuous body 101 emits light, each filament 120 has a uniform calorific value distribution over the width L from the center to both ends. When both filament continuum are turned on, they are arranged so as to have a substantially uniform calorific value distribution as a whole.
[0028]
Next, a method of switching the heating width of the heating roller according to the width of the printing paper will be described.
[0029]
As shown in the circuit diagram of FIG. 3, the switching elements SW1 and SW2 connected in series to the first and second filament continuum bodies 101 and 102, respectively, and the first and second filament continuity bodies 101 and 102 are arranged in parallel. A switching element SW3 connected between the circuit and the power supply P is provided, and the switching width of the switching elements SW1, SW2, and SW3 is switched on and off to control the heating width of the heating roller. Each of the switching elements SW1 to SW3 is a switching element with a control terminal such as a triac, and controls on / off according to a control signal transmitted from the heating control unit 200.
[0030]
For example, it is assumed that this image forming apparatus can print A3 paper (297 mm) in full width, and the printing paper is centered. Here, when the predetermined length is set to a width corresponding to the width of B5 paper (182 mm), when printing a narrower width than vertical printing of B5 paper, for example, letter size, legal paper, standard postcard, etc. First, the switching elements SW1 and SW3 are turned on, and the switching element SW2 is turned off, so that only the first filament continuous body 101 emits light and the heating roller is partially heated. When printing on A4 paper, B4 paper, or A3 paper, all the switching elements SW1 to SW3 are turned on, the first and second filament continuum bodies 101 and 102 emit light, and the heating roller becomes the full width. Heat with.
[0031]
The switching elements SW1 to SW3 are turned on and off by the heating control unit 200. The heating control unit 200 detects the width of the printing paper by the paper width detection sensor 203 attached to the image forming apparatus, and detects this. The required heating width is selected based on the result, and ON / OFF of the switching elements SW1 to SW3 is controlled.
[0032]
As described above, the heating roller can be heated to a required width by selectively emitting light from the filament in accordance with the width of the printing paper. This eliminates the need to heat the entire width of the heating roller even when printing printing paper with a narrow printing width, as in the related art, thereby reducing power consumption.
[0033]
Further, since only one halogen heater lamp is required, the processing of the body of the heating roller and the arrangement of the halogen heater lamp are facilitated, and the manufacturing cost can be reduced.
[0034]
In the present embodiment, the heating width of the first filament continuous body is set to the B5 paper width (182 mm). However, the present invention is not limited to this. For example, the A4 paper width (210 mm) may be used in response to a request from the user. Then, it may be set in advance. Also, the overall width can be determined in the same manner according to the device specifications.
[0035]
In the present embodiment, the case where the print width is detected by the paper width detection sensor has been described. However, when the user selects a desired print paper and inputs it to the image forming apparatus, the print paper information based on the input print paper information is obtained. Thus, the ON / OFF of the switching elements SW1 to SW3 can be controlled by the heating control unit.
[0036]
Further, in the present embodiment, the printing paper alignment position is the center of the heating roller. However, the printing paper alignment position may be the end of the heating roller. In this case, as shown in FIG. The filament continuum 101 has a plurality of filaments 120 disposed within a range of a predetermined length L from one end thereof, and the second filament continuum 102 extends from the position of the predetermined length L to the other end. A plurality of filaments 120 may be provided within the range.
[0037]
In the present embodiment, the lamp tube shape of the halogen heater lamp is shown as a straight tube having a spectacle shape in cross section. However, the cross section may be oval or elliptical.
[0038]
【The invention's effect】
As described above, according to the image forming apparatus of the present invention, two filament continuous bodies each having a different heating value distribution in the axial direction are arranged in parallel inside one halogen heater lamp, and the heating control means By heating either or both of the filament continuum with, a heating source having a plurality of different heating value distributions is configured. With this, the heating range of the heating roller can be selected according to the width of the recording medium such as printing paper, and when printing a recording medium having a printing width equal to or less than a preset printing width, both ends of the heating roller are heated. Power consumption can be reduced. Further, since the heating width can be switched by one halogen heater lamp, the process of incorporating the halogen heater lamp into the heating roller can be simplified, and the manufacturing cost can be suppressed.
[0039]
Further, according to the image forming apparatus of the present invention, the distance between each of the first and second filament continuous bodies to the point where the toner on the surface of the recording medium is heated and fixed by the pressing roller is equalized, so that the filament to be heated can be formed. Even when the continuum is switched, there is no need to change the heat transfer efficiency to the heat fixing point, and the heating control is facilitated.
[0040]
Further, according to the image forming apparatus of the present invention, the heating range in the axial direction is different between the first filament continuous body and the second filament continuous body, and the width that can be heated by the first filament is printed. By setting in advance with reference to the widths of a plurality of types of recording materials, when printing a recording material whose printing width is smaller than the predetermined width, power is supplied only to the first filament continuous body to control the heating roller. Heat only a predetermined width. When printing a recording medium having a printing width wider than the predetermined width, power is supplied to both filament continuous bodies to heat the entire heating roller. Thereby, the heating range of the heating roller can be switched according to the printing width of the recording medium.
[0041]
Further, according to the image forming apparatus of the present invention, when the reference position in the printing width direction of the recording body is at the center in the width direction and the printing width is smaller than a predetermined width, the printing is performed on the recording body. Electric power is supplied to only one filament continuous body to heat only a predetermined width including the center of the heating roller. When printing on a recording medium having a printing width wider than a predetermined width, the recording medium is printed at the center of the heating roller by supplying power to both filament continuous bodies and heating the entire heating roller. Also in this case, the heating range of the heating roller can be switched according to the printing width.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of an image forming apparatus according to the present invention. FIG. 2 is an external perspective view, an equivalent circuit diagram, and a calorific value distribution diagram of a halogen heater lamp according to the present invention. FIG. FIG. 4 is an equivalent circuit diagram and a calorific value distribution diagram of a halogen heater lamp of another configuration. FIG. 5 is an external perspective view, an equivalent circuit diagram, and a calorific value distribution diagram of a conventional halogen heater lamp. FIG. 6 is a schematic diagram showing a configuration of a conventional heating roller.
1—Photosensitive drum 2—Charging roller 3—Developing syringe 4—Cartridge 5—Transfer roller 6—Heating roller 7—Pressing roller 8—Cleaning section 30—Printing paper 31 as a recording medium—Transfer surface 40 of printing paper 30— Toner 61-body 62 of heating roller 6-coating layer 71 of heating roller 6-body 72 of pressure roller 7-coating layer 100, 100a, 10b of pressure roller 7-halogen heater lamps 101, 102, 111, 111a, 111b-filament continuum 103, 104-outer lead 105-connector 110-lamp tube 120-filament 121-inner lead 200-heating controller 300-paper width detection sensor P-power supply

Claims (7)

An image forming apparatus for electrophotography, which forms an image on the surface of a recording medium by heating and fixing a toner image formed as a charged image on the surface of the recording medium with a heating roller having a built-in heating source including a halogen heater lamp. At
The halogen heater lamp includes first and second filament continuums each having a plurality of filaments connected in series in the lamp tube so as to be parallel to each other in the axial direction of the lamp tube so that heat generation amount distributions in the axial direction are different from each other. ,and,
(1) When the reference position in the printing width direction of the recording medium is the center in the axial direction of the heating roller, the plurality of filaments of the first filament continuous body are moved from the axial center of the filament continuous body to both ends. Direction, and a plurality of filaments of the second filament continuum are disposed at both ends from a position apart from the axial center of the filament continuity by the predetermined width, and
(2) When the reference position in the printing width direction of the recording body is one end in the axial direction of the heating roller, a plurality of filaments of the first filament continuous body are set in a predetermined manner from one end of the filament continuous body. A plurality of filaments of the second filament continuum are arranged from a position at a predetermined length from the one end to the other end,
Further, the plane including the respective axes of the first and second filament continuities arranged in parallel with each other and the conveyance path of the recording medium are parallel to each other, and the center of the halogen heater lamp in the axial direction is set. And, disposed on the heating roller so that the axial center of the heating roller coincides,
Heating control means for selecting at least one of the first and second filament continuous bodies of the halogen heater lamp to generate heat,
The image forming apparatus, wherein the heating control unit causes at least one of the first and second filament continuous bodies to generate heat in accordance with a printing width of the recording body. An image forming apparatus that forms an image on the surface of the recording medium by heating and fixing the toner image formed on the surface of the recording medium with a heating roller including a heating source including a halogen heater lamp,
The halogen heater lamp is an image forming apparatus in which a first and a second filament continuous body each having a plurality of filaments connected in series are arranged in a lamp tube in parallel with an axial direction of the lamp tube. 3. The image forming apparatus according to claim 2, wherein the first and second filament continuous bodies are each provided with a plurality of filaments such that heat distributions in the axial direction thereof are different from each other. 4. The image forming apparatus according to claim 2, further comprising a heating control unit that selects at least one of the first and second filament continuous bodies to generate heat. 5. 5. The image forming apparatus according to claim 2, wherein a plane including respective axes of the first and second filament continuous bodies arranged in parallel is parallel to a conveyance path of the recording body. 6. . The said 1st filament continuous body and the said 2nd filament continuous body do not overlap in the axial direction of a filament continuous body in the arrangement direction of the some filament connected in series, respectively. Image forming apparatus. The first filament continuum has a plurality of filaments arranged in a predetermined width in both directions from the center in the axial direction of the filament continuum, and the second filament continuity has an axial center from the filament continuity. The image forming apparatus according to any one of claims 2 to 6, wherein a plurality of filaments are arranged from both positions apart from the predetermined width.

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