JP2017117669A - Heater, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater which can be shortened in a longitudinal direction and is easily inserted into a fixing roller.SOLUTION: Disclosed is a heater 30 in which a filament 350 is arranged in a cylindrical valve 310 and harnesses 340 are pulled out from base members 32 at both ends of the valve 310. The direction of a portion (a second base member 322) where the harness 340 is pulled out from the base member 32 is made movable between the longitudinal direction of the valve 310 and the direction intersecting with the longitudinal direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to a heater, a fixing device including the heater, and an image forming apparatus.

In image forming devices such as electrophotographic copying machines and printers, halogen heaters are often used as a heat source for fixing devices that fix images on paper by heat, and dehumidifying devices that dehumidify paper in a paper cassette. Is done. There are at least three types of AC power supply connection structures of the halogen heater, the first is the harness type shown in FIGS. 6A and 6B, the second is the socket press-contact type shown in FIG. 6C, and the third is the same figure (d). ) Terminal screw fixing type.

6 (a) and 6 (b), the filament 102 in the valve 100 is connected to the lead rod 108 via the lead wire 104 and the molybdenum foil 106, and one end of the harness 110 is spotted on the outer end of the lead rod 108. It welds in the welding part 112. FIG. A connector terminal 114 or a round terminal 116 is connected to the other end of the harness 110.

In the socket pressure contact type of FIG. 6C, a terminal 130 is provided on the end face of a base 118 such as ceramic, and the unit-side electrode plate 132 is brought into contact with the terminal 130. In the terminal screw fixing type of FIG. 6D, a terminal plate 140 is connected to the end portion of the lead bar 108, and the terminal plate 140 is fastened to the AC harness on the unit side with screws. In FIG. 6, 110a is a lead wire of the harness 110, 120 is a supporter for supporting the filament 102, and 122 is a pressure contact portion of the lead wire 110a.

Since all the conventional heaters have harnesses and terminals extending from both ends of the valve in the longitudinal direction of the valve, it is necessary to secure a space in the longitudinal direction in the apparatus in which the heater is disposed. For this reason, the size of the apparatus is increased. For example, in the case of the harness type, the heater does not fit in the apparatus at the distance L1 between the cap ends, as shown in FIG. 7A. The minimum length of L2 plus

In order to shorten the longitudinal direction of the heater, the harness 110 may be taken out from the base 118 at a right angle as shown in FIG. 7B. However, for example, the harness 110 becomes an obstacle in the process of incorporating the heater into the fixing roller of the fixing device. The heater cannot be inserted into the fixing roller.

An object of the present invention is to provide a heater which can be shortened in the longitudinal direction and can be easily inserted into a fixing roller of a fixing device.

The present invention solves the above-described problem, and includes a cylindrical valve, a filament disposed in the longitudinal direction in the valve, and holding both ends of the filament at both ends of the valve, and In a heater having a base member from which a harness for supplying electric power is drawn, the direction of the harness drawing portion of at least one of the base members is between the longitudinal direction of the valve and the direction intersecting the longitudinal direction. It is the heater characterized by having comprised so that it was movable.

According to the present invention, it is possible to provide a heater that can be shortened in the longitudinal direction and can be easily inserted into a fixing roller of a fixing device.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram of a fixing device of an image forming apparatus. FIG. 3 is a schematic perspective view of a heater of the fixing device. It is an edge part perspective view of the heater before an assembly. It is an edge part perspective view of the heater after an assembly. It is an edge part side view of the heater which shows the rotation state of a base member. It is an edge part side view which shows the AC power supply connection structure of the conventional halogen heater. It is a perspective view of the conventional harness type heater. It is a perspective view of a heater at the time of taking out a harness at right angles.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings for explaining the embodiments, constituent elements such as members and components having the same function or shape are given the same reference numerals as much as possible, and once explained, the explanation will be given. Omitted.

(Image forming device)
The image forming apparatus shown in FIG. 1 is a schematic configuration diagram of an electrophotographic monochrome image forming apparatus as an image forming apparatus according to an embodiment of the present invention. The overall configuration and operation of the image forming apparatus will be described first with reference to FIG. A process unit 1 as an image forming unit is detachably attached to the apparatus main body 200 of the monochrome image forming apparatus. The process unit 1 includes a photoreceptor 2 as an image carrier that carries an image on the surface, and a charging roller 3 as a charging unit that charges the surface of the photoreceptor 2.

The process unit 1 also includes a developing device 4 as a developing unit that visualizes a latent image on the photoreceptor 2 and a cleaning blade 5 as a cleaning unit that cleans the surface of the photoreceptor 2. An LED head array 6 serving as an exposure unit that exposes the surface of the photoconductor 2 is provided at a position facing the photoconductor 2.

The process unit 1 is detachably provided with a toner cartridge 7 as a developer container. The toner cartridge 7 has a developer accommodating portion 8 that accommodates toner as a developer to be replenished to the developing device 4 in the container main body 22. Furthermore, the toner cartridge 7 of this embodiment also has a developer recovery unit 9 that recovers the toner (waste toner) removed by the cleaning blade 5.

The photoconductor 2, the charging roller 3, the LED head array 6, the developing roller 23, and the cleaning blade 5 are all integrally provided on the support body of the process unit 1. Thereby, these parts can be exchanged at once by attaching / detaching the process unit 1 to / from the apparatus main body 200.

The image forming apparatus includes a transfer device 10 that transfers an image to a sheet as a recording medium, a sheet feeding device 11 that supplies the sheet, a fixing device 12 that fixes the image transferred to the sheet, and discharges the sheet to the outside. And a paper discharge device 13 for performing the operation.

The transfer device 10 includes a transfer roller 14 as a transfer member. The transfer roller 14 is in contact with the photosensitive member 2 with the process unit 1 mounted on the apparatus main body 200, and a transfer nip is formed at the contact portion between the two. Further, a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to the transfer roller 14 by a power source.

The paper feed device 11 includes a paper feed cassette 15 that contains paper P and a paper feed roller 16 that feeds the paper P contained in the paper feed cassette 15. The sheet fed from the sheet feeding device 11 is conveyed in the direction indicated by the dotted arrow in the drawing along the conveyance path provided in the apparatus main body 200.

In this transport path, as a recording medium transport means for transporting the paper to the transfer nip at a transport timing, downstream of the paper feed roller 16 in the paper transport direction and upstream of the transfer roller 14 in the paper transport direction. A pair of timing rollers 17 is provided. The paper P includes cardboard, postcard, envelope, plain paper, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like. Further, an OHP sheet, an OHP film, or the like can be used as a recording medium other than paper.

The fixing device 12 includes a fixing roller 18 as a fixing member and a pressure roller 19 as a pressure member. The fixing roller 18 is heated by a heater 30 installed inside the fixing roller 18. The pressure roller 19 is pressed toward the fixing roller 18 and comes into contact with the fixing roller 18, and a fixing nip N is formed at the contact portion.

The paper discharge device 13 includes a pair of paper discharge rollers 20. The paper discharged out of the apparatus by the paper discharge roller 20 is stacked on a paper discharge tray 21 formed by denting the upper surface of the apparatus main body 200.

(Image forming operation of image forming device)
Next, an image forming operation of the image forming apparatus according to the present embodiment will be described with reference to FIG. When the image forming operation is started, the photosensitive member 2 is rotationally driven, and the surface of the photosensitive member 2 is uniformly charged to a predetermined polarity by the charging roller 3.

Then, based on image information from a reading device or a computer, light is emitted from the LED head array 6 to the surface of the photoreceptor 2, and an electrostatic latent image is formed on the charged surface of the photoreceptor 2. By supplying toner from the developing roller 23 to the electrostatic latent image formed on the photosensitive member 2 in this way, the electrostatic latent image is visualized (visualized) as a toner image.

When the image forming operation is started, the paper feed roller 16 starts to rotate, and only the uppermost paper among the papers stored in the paper feed cassette 15 is sent out to the transport path. The fed paper is temporarily stopped by the timing roller 17. Thereafter, rotation of the timing roller 17 is started at a predetermined timing, and the paper is conveyed to the transfer nip in accordance with the timing at which the toner image on the photoreceptor 2 reaches the transfer nip.

At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the photoreceptor 2 is applied to the transfer roller 14, thereby forming a transfer electric field in the transfer nip. Then, the toner image on the photoreceptor 2 is transferred onto the paper by this transfer electric field. The residual toner on the photoreceptor 2 that could not be transferred onto the paper is removed by the cleaning blade 5. Thereafter, the sheet is conveyed to the fixing device 12 and the toner image on the sheet is fixed. Then, the paper is discharged onto the paper discharge tray 21 by the paper discharge roller 20.

(Fixing device)
Next, the configuration of the fixing device 12 described above will be described. As shown in FIG. 2, the fixing device 12 includes two rotating bodies, that is, a fixing roller 18 as a fixing member that forms a fixing nip N in contact with each other, and a pressure roller 19 as a pressure member.

The fixing roller 18 is a cylindrical member in which the periphery of the heat conductive substrate is covered with a layer having releasability. As the heat conductive substrate, a carbon steel material or aluminum material having a required mechanical strength and good heat conductivity is mainly used.

The release layer on the outer side (outer peripheral surface) is made of a material having good release properties with toner, high thermal conductivity, and high durability. For example, those coated with a fluororesin (PFA) tube, those coated with a fluororesin (PFA or PTFE) paint, or those formed with a silicone rubber layer or a fluororubber layer are used as the coating layer. Inside the fixing roller 18, a heater 30 is arranged as a heating source for heating the fixing roller 18.

The pressure roller 19 is a cylindrical member including a cored bar, an elastic layer formed on the outer side (outer periphery) of the cored bar, and a coating layer that covers the elastic layer. For example, STKM or the like is used as the core metal, and silicone rubber, fluorine rubber, or a foam thereof is used as the elastic layer. The covering layer is formed of, for example, a tube of heat-resistant fluororesin such as PFA or PTFA rich in releasability. The pressure roller 19 is urged toward the fixing roller 18 by an urging mechanism using a spring or the like.

(Fixing device operation)
Next, the operation of the fixing device will be described. When the image forming operation is started, electric power is supplied to the heater 30, and the fixing roller 18 is heated by the heater 30. Further, the fixing roller 18 and the pressure roller 19 start to rotate clockwise in FIG.

Then, the paper P on which the unfixed toner image T is transferred through the transfer step is fed into the fixing nip N between the fixing roller 18 and the pressure roller 19. As a result, the paper P and the toner image T are heated and pressurized in the fixing nip N, and the toner image T is fixed on the paper P. Thereafter, the paper P is sent out from the fixing nip N and is discharged out of the apparatus as described above.

(Heater configuration)
FIG. 3 shows a configuration of the heater 30 according to an embodiment of the present invention. The heater 30 is a harness type halogen heater. The heater 30 has a cylindrical or cylindrical valve 310 as in the conventional heater. The valve 310 is a straight tubular member made of quartz glass or the like, and an inert gas is sealed in the manufacturing process by replacing the internal air from the chip 312 on the outer peripheral surface of the valve 310.

A filament 350 as a heating element is arranged along the longitudinal direction in the bulb 310. The filament 350 is formed by forming a metal wire such as tungsten in a coil shape. The filament 350 is supported coaxially with the valve 310 by a rod-like support 351 disposed in the center of the bulb 310, and both ends of the filament 350 are connected to the molybdenum foil 352.

Both end portions of the valve 310 are flattened seal portions 311, and a molybdenum foil 352 is fixed in the seal portion 311. A harness 340 is drawn from the molybdenum foil 352 through a lead bar. The lead-out structure of the harness 340 is the same as that in FIGS. 6A and 6B, and the round terminal 341 or the connector terminal 114 as shown in FIG.

FIG. 3 is a diagram in which the rotary harness 340 is applied to one end of the heater 30. In the present embodiment, the rotary harness is applied only to one end of the heater 30, but it is also possible to apply the rotary harness to both ends in order to shorten the length of the heater 30.

4A and 4B are enlarged views of one end of the heater on the rotating harness side. In the configuration of the present embodiment, the base member 320 includes two members, one first base member 321 is fixed to the end of the seal portion 311 at the valve end, and the other second base member 322 is the first base member. 321 is connected to be rotatable.

Specifically, the first base member 321 and the second base member 322 are formed into a substantially rectangular parallelepiped outer shape with a heat-resistant material (for example, a heat-resistant material such as ceramic or a heat-resistant resin such as PPS, PET, PTFE, or PAI). The first base member 321 on the fixed side has a pair of left and right bracket portions 321 a on both side portions of the end surface facing the axial direction of the valve 310. And the 2nd base member 322 is arrange | positioned rotatably between the said bracket parts 321a.

The second base member 322 has an end plate 322a and a pair of left and right ear portions 322b, and the pair of ear portions 322b are rotatably supported by the bracket portions 321a via a pair of support shafts 330. The second base member 322 is configured to be rotatable from the state shown in FIG. 4A to the state shown in FIG. The end plate 322a has a fool hole 322c through which the harness 340 is slidable in the longitudinal direction, and a base end portion of the harness 340 is slidably passed through the flaw hole 322c.

FIG. 5 shows a cross section of FIG. 4B viewed from the side. Since the second base member 322 is configured to be rotatable about the support shaft 330, the space is saved, and it is not necessary to secure a wide space around the second base member 322.

In this embodiment, when the heater 30 is inserted into the fixing roller 18 at the time of assembly, the drawing direction of the harness 340 is extended in parallel with the longitudinal direction of the valve 310 as shown by a one-dot chain line in FIG. After the heater 30 is inserted into the fixing roller 18, the second base member 322 is rotated 90 ° upward about the support shaft 330 as shown in FIG. 4B, and the drawing direction of the harness 340 is perpendicular to the longitudinal direction of the valve 310. In the direction.

By doing so, the harness 340 does not interfere with the insertion into the fixing roller 18 during assembly, and after assembly, the harness 340 protrudes from the second base member 322 in the longitudinal direction of the valve 310 as shown in FIG. 4A. The total length of the heater can be shortened by the amount. In many cases, the heater 30 is the longest part in the fixing device 12, and the shortening of the total length of the heater directly leads to a reduction in the width or miniaturization of the fixing device 12.

(Modification of heater)
The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, the rotatable harness 340 is configured to be rotatable by 90 ° at the maximum as shown in FIG. 5, and when there is a space that does not interfere with the harness 340 on the apparatus main body side, a part of the space is used. For example, the harness 340 can be configured to be rotatable at 90 ° or less, or the harness 340 can be configured to be rotatable at 90 ° or more, for example, up to 120 °.

Moreover, the structure which makes the 2nd base member 322 movable with respect to the 1st base member 321 of a fixed side is a structure which connects both members with a thin-plate-like hinge other than the structure which connects both members with the support shaft 330. Alternatively, a pluggable detachable connection structure using a plurality of ridges and grooves formed at different angles on the inner surface of the bracket portion 321a and the side surface of the second base member 322 may be used.

In addition, when a sufficient space is provided on one side in the longitudinal direction of the fixing roller 18 and the pressure roller 19 to arrange a driving unit such as a gear for rotating the fixing roller 18 and the pressure roller 19, a part of the space is used. The stationary harness 340 extending along the longitudinal direction of the valve 310 can be disposed. Thereby, even when only one of the harnesses 340 is configured to be rotatable, the apparatus can be reduced in size at a low cost.

In the above embodiment, the case where the present invention is applied to the heater 30 disposed inside the fixing roller 18 has been described as an example. However, the present invention is not limited to the heater disposed outside the fixing roller 18 or the pressure roller 19. The present invention can also be applied to a heater or the like disposed inside or outside the heater. In addition, the present invention is not limited to the heater installed in the fixing device 12 but can be applied to a heater that dehumidifies by heating a sheet stored in a sheet feeding cassette (before being supplied to the image forming unit). .

Further, the image forming apparatus provided with the heater according to the present invention is not limited to the monochrome image forming apparatus as shown in FIG. 1, and may be a color image forming apparatus. The image forming apparatus may be a printer, a copier, a facsimile, or the like. Or a multi-function machine.

12: fixing device 18: fixing roller 19: pressure roller 30: heater 32: base member 321: first base member 322: second base member 310: valve 330: spindle 340: harness 350: filament 352: molybdenum foil

JP 2004-279696 A

Claims (5)

A tubular valve,
A filament disposed longitudinally within the bulb;
In a heater having a base member that pulls out a harness that holds both ends of the filament at both ends of the bulb and supplies power to the filament,
A heater characterized in that the orientation of the harness drawing portion of at least one of the base members is movable between a longitudinal direction of the valve and a direction intersecting the longitudinal direction.   The base member includes a first base member fixed to an end of the valve, and a second base member that is rotatably connected to the first base member and the harness is pulled out. The heater according to claim 1.   The first base member and the second base member are connected via a rotation shaft perpendicular to the longitudinal direction of the valve, and the second base member is movable within a range of up to 90 ° around the rotation shaft. The heater according to claim 2, wherein the heater is configured.   A fixing device comprising the heater according to claim 1.   An electrophotographic image forming apparatus comprising the fixing device according to claim 4.