JP2015122144A - Infrared heater, fixing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared heater that suppresses the temperature rise of junctions of a heat generator and lead wires to be used stably for a long period.SOLUTION: There is provided an infrared heater 10 that includes a heat generator 3, lead wires 6 configured to be conductive with the heat generator 3, and junctions 7 of the heat generator 3 and the lead wires 6, and further includes members that are arranged to be in contact with the atmosphere outside the infrared heater 10 and have a function to dissipate the heat of the junctions 7 to the outside of the infrared heater 10.

Description

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

An infrared heater used in an image forming apparatus such as an MFP (multifunction printer) includes a heating element, a lead wire connected to the heating element, and a joint portion between the heating element and the lead wire. Is generally popular.
However, in the sealing portion that seals the joint portion, the temperature rises due to heat transfer, causing melting and carbonization at the joint portion between the filament and the lead wire inside the envelope, and shortening the life. is there.

Here, in Patent Document 1 (Japanese Patent No. 4523050), a heat radiating portion is provided at the end of the heating element inside the sealing body to prevent a temperature rise of the sealing portion.
However, since the end portion of the heat generating portion is a region that does not generate heat, the width that is essential for the structure is increased with respect to the width that requires heat generation (heating), leading to an increase in the size of the infrared heater itself. This hinders miniaturization of the entire apparatus using the heater.
Moreover, since the thermal radiation part of patent document 1 is provided in the inside of a sealing body, it is low as a thermal radiation function, and suppression of the further temperature rise is calculated | required.

  The present invention has been made in view of the above problems in the prior art, and provides an infrared heater that can be used stably over a long period of time by suppressing the temperature rise at the joint between the heating element and the lead wire. Objective.

  An infrared heater according to the present invention for solving the above problems is an infrared heater including a heating element, a lead wire connected to the heating element, and a joint portion between the heating element and the lead wire. And a member disposed so as to be in contact with the atmosphere outside the infrared heater and having a function of radiating the heat of the joint to the outside of the infrared heater.

  ADVANTAGE OF THE INVENTION According to this invention, the infrared heater which can be used stably for a long term can be provided by suppressing the temperature rise of the junction part of a heat generating body and a lead wire.

It is an external appearance perspective view which shows the structure of the conventional infrared heater. It is a schematic sectional drawing which shows the structure of the conventional infrared heater. (A) It is a schematic sectional drawing which shows the structure in 1st Embodiment of the infrared heater which concerns on this invention. (B) It is a schematic sectional drawing which shows the structure in 2nd Embodiment of the infrared heater which concerns on this invention. (A) It is a schematic sectional drawing which shows the structure in 3rd Embodiment of the infrared heater which concerns on this invention. (B) It is a schematic sectional drawing which shows the structure in 4th Embodiment of the infrared heater which concerns on this invention. (A) It is a schematic sectional drawing which shows the structure in 5th Embodiment of the infrared heater which concerns on this invention. (B) It is a schematic sectional drawing which shows the structure in 6th Embodiment of the infrared heater which concerns on this invention. 1 is a schematic diagram illustrating a configuration in an embodiment of an image forming apparatus according to the present invention.

The infrared heater according to the present invention is an infrared heater 10 including a heating element 3, a lead wire 6 that is electrically connected to the heating element 3, and a joint portion 7 between the heating element 3 and the lead wire 6. And a member disposed so as to be in contact with the atmosphere outside the infrared heater 10 and having a function of radiating the heat of the joint 7 to the outside of the infrared heater 10.
Next, the infrared heater and the image forming apparatus according to the present invention will be described in more detail.
Although the embodiments described below are preferred embodiments of the present invention, various technically preferable limitations are attached thereto, but the scope of the present invention is intended to limit the present invention in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

<Infrared heater>
Prior to describing the present invention, an example of the configuration of a conventional infrared heater will be described with reference to FIGS.
FIG. 1 is an external perspective view showing the configuration of a conventional infrared heater, and FIG. 2 is a schematic sectional view showing the configuration of a conventional infrared heater.
The infrared heater 10 has a cylindrical shape, and has sealing portions 1 at both ends thereof. Furthermore, the sealing part 1 has the terminal 2 connected with the lead wire 6 at each tip.
In the cross-sectional view shown in FIG. 2, the filament 3 that is a heating element inside the sealed body is schematically illustrated. In the sealing part 1, the filament 3 and the lead wire 6 are joined at the joint 7.

(First and second embodiments)
Next, an embodiment of the infrared heater according to the present invention will be described.
FIG. 3A is a schematic cross-sectional view showing the configuration of the infrared heater according to the first embodiment of the present invention, and FIG. 3B is the configuration of the infrared heater according to the second embodiment of the present invention. It is a schematic sectional drawing which shows.
In the first embodiment and the second embodiment, the heat radiating member 4 which is a member having a function of radiating heat is disposed around the sealing portion 1 (both ends of the infrared heater 10 and closer to the center than the terminal 2). (Outside air) is provided in contact with.

In the first embodiment shown in FIG. 3A, the comb-like heat radiating member 4a is provided so that the tooth portion is perpendicular to the axial direction of the infrared heater 10, and the infrared heater 10 has both ends thereof. The disposed sealing portions 1 are provided on the upper and lower sides in FIG. 3A (four in total).
Further, in the second embodiment shown in FIG. 3B, the comb-like heat radiating member 4b is provided so that the tooth portion extends perpendicularly to the axial direction of the infrared heater 10 and in the end direction. The sealing portions 1 disposed at both ends of the infrared heater 10 are respectively provided above and below in FIG. 3B (four in total).
The heat dissipating member 4 has a function of suppressing the temperature rise, and the shape thereof is a comb-like shape (having an uneven shape), so that the member has a large surface area and can efficiently dissipate heat.

In the said 1st Embodiment and 2nd Embodiment, although the comb-shaped heat dissipation member 4 is used, this invention is not limited to this shape, Various uneven | corrugated shapes other than a comb-tooth shape, Any shape can be used as long as the surface area can be increased and heat can be radiated to the surroundings.
In both the first embodiment and the second embodiment, the shape of the heat dissipation member 4 is the same at both ends and above and below, but the present invention is not limited to this. Note that it is preferable that the provided heat dissipating members 4 have the same shape and the arrangement relationship is symmetric, because the heat dissipating behavior is also symmetric and the number of parts is reduced.
However, each of the heat radiating members 4 may have a different shape or an asymmetrical arrangement relationship from the arrangement relationship with surrounding members.

In the present invention, the member having a function of radiating heat is not particularly limited as long as it can realize desired heat radiating, but a member that realizes heat radiating with high thermal conductivity and a large surface area is preferable.
As the material of the heat radiating member 4a and the heat radiating member 4b, a material having excellent thermal conductivity has a high heat radiating effect, and in particular, a material having a high thermal conductivity of 50 [W / m · K] or more is effective. Temperature rise can be suppressed. Furthermore, it is more preferable to use a material having a high thermal conductivity of 60 [W / m · K] or more.
As a material having a thermal conductivity of 50 [W / m · K] or more, a well-known and commonly used material can be used, and examples thereof include nickel and tungsten.

  According to the first embodiment and the second embodiment described above, the temperature rise of the joint portion 7 (and the sealing portion 1) between the filament 3 and the lead wire 6 inside the envelope is suppressed, and the temperature rises. Therefore, the infrared heater can be used as a heat source stably for a long period of time. That is, according to the structure of the said 1st Embodiment and 2nd Embodiment, heat dissipation efficiency can be improved with the heat radiating member 4 by setting it as the structure where the surface area of the heat radiating member 4 is large.

(Third and fourth embodiments)
FIG. 4A is a schematic sectional view showing the configuration of the infrared heater according to the third embodiment of the present invention, and FIG. 4B is the configuration of the infrared heater according to the fourth embodiment of the present invention. It is a schematic sectional drawing which shows.
In the third embodiment and the fourth embodiment, the shape of the terminal 2 is different from the conventional one and functions as a member having a function of radiating heat.

In the third embodiment shown in FIG. 4A, the opposite sides of the outer periphery of the terminal 2a are comb-like, and the teeth are perpendicular to the axial direction of the infrared heater 10 as shown. It is provided to become.
In the fourth embodiment shown in FIG. 4 (b), the opposite sides of the outer periphery of the terminal 2b have a saw-blade shape (a jagged shape), and the crest portion of the saw blade is as shown in the figure. It is provided so as to be perpendicular to the axial direction of the infrared heater 10.

The terminal 2a and the terminal 2b have a heat dissipation function, and are provided with a concavo-convex shape for increasing the surface area in order to efficiently dissipate the heat transmitted through the lead wire 6, and are in contact with the surroundings (outside air).
That is, the terminal 2 is provided in contact with the lead wire 6 and has a function of suppressing a temperature rise (heat radiation function) by radiating the heat transferred from the uneven shape of the terminal 2, and the shape is uneven.

In the third embodiment and the fourth embodiment, the comb-shaped terminal 2a and the saw blade-shaped terminal 2b are used, respectively, but the present invention is not limited to this shape, and the surface area is increased. Any shape may be used as long as heat can be radiated to the surroundings.
In the third and fourth embodiments, the shape of the terminal 2 is vertically symmetrical (in FIG. 4), but the present invention is not limited to this. Note that it is preferable that the shape of the terminal 2 is vertically symmetric because the heat dissipation behavior is also symmetric.
However, the shape of the terminal 2 may be asymmetric in the vertical direction due to the arrangement relationship with surrounding members.

  In addition, about the material, thermal conductivity, and surface area of the terminal 2a and the terminal 2b, the thing similar to the material, thermal conductivity, and surface area of the heat radiating member 4a and the heat radiating member 4b mentioned above can be illustrated as a preferable example.

According to the third embodiment and the fourth embodiment described above, the temperature rise of the joint portion 7 (and the sealing portion 1) between the filament 3 and the lead wire 6 inside the envelope is suppressed, and the temperature rises. Therefore, the infrared heater can be used as a heat source stably for a long period of time. That is, according to the configuration of the third embodiment and the fourth embodiment, the heat radiating member 4 can be obtained by configuring the terminal 2 connected to the joint portion 7 (and the lead wire 6) to have a large surface area. Therefore, the heat dissipation efficiency can be improved.
Moreover, according to the structure of the said 3rd Embodiment and 4th Embodiment, without adding the member only for it as a member which has a function to thermally radiate, it serves as the terminal 2 as an electrode. The heat dissipation efficiency can be improved with an inexpensive and simple configuration.
In addition, it is good also as a structure which further provided the heat radiating member 4 which was demonstrated in the form of the said 1st Embodiment and 2nd Embodiment.

(5th Embodiment and 6th Embodiment)
FIG. 5 (a) is a schematic sectional view showing the configuration of the infrared heater according to the fifth embodiment of the present invention, and FIG. 5 (b) shows the configuration of the infrared heater according to the sixth embodiment of the present invention. It is a schematic sectional drawing.
A heat shield member 5 is provided between the end of the filament 3 and the sealing portion 1 so as to prevent heat from the filament 3 in the envelope, which is a heating element, from traveling to the sealing portion 1.
In the fifth and sixth embodiments, illustration of the terminal 2 or the heat radiating member 4 which is a member having a function of radiating heat is omitted.
Further, the shielding member 5 is shown in FIG. 5 in a cross-sectional shape parallel to the axis of the infrared heater, but three-dimensionally surrounds the periphery (in the cross-sectional shape perpendicular to the axis of the infrared heater, for example, the outer periphery Is a circular cross-sectional shape).

In the fifth embodiment shown in FIG. 5A, the position is upright so as to be perpendicular to the axial direction of the infrared heater 10, and the position between the filament 3 and the sealing portion 3 in the axial direction. And a heat shielding member 5a comprising a portion formed continuously with this portion and covering a corner of the infrared heater 10 (three-dimensionally, a circumferential portion at the axial end). Is provided.
Further, in the sixth embodiment shown in FIG. 5B, the upright position is perpendicular to the axial direction of the infrared heater 10, and the sealing portion 3 and the joint portion 7 are arranged in the axial direction. A heat shield member 5b provided at a position between them is provided. The heat shield member 5b is fixed to a fixing device main body as fixing means by a locking member (not shown).
The material of the heat shielding member 5a and the heat shielding member 5b is not particularly limited as long as it has a heat shielding effect, and a well-known and conventional material can be used.

  According to the third embodiment and the fourth embodiment described above, by providing the heat shield member 5 between the filament 3 that is a heating element of the infrared heater 10 and the terminal 2 or the heat radiating member 4. It is possible to suppress the temperature around the terminal 2 or the heat radiating member 4 and enhance the heat radiation effect.

<Image forming apparatus>
Next, a basic configuration of a copying machine 100B which is an embodiment of an image forming apparatus according to the present invention will be described. The image forming apparatus according to the present invention includes the above-described infrared heater 10 in the fixing device 25 as a fixing unit.
FIG. 6 is a schematic configuration diagram showing the configuration of the copying machine 100B. The copying machine 100B is a tandem color image forming apparatus, and includes a printer unit 150, which is a main body of the image forming apparatus, a paper feeding device 200, a scanner 300, and an automatic document feeder (ADF) 400.

The printer unit 150 is provided with an endless belt-shaped intermediate transfer belt 50 at the center. The intermediate transfer belt 50 is stretched around three support rollers including a belt driving roller 14, a cleaning counter roller 15 and a secondary transfer counter roller 16, and is rotatable clockwise in FIG. In the vicinity of the cleaning counter roller 15, an intermediate transfer belt cleaning device 17 that is an intermediate transfer belt cleaning unit for removing residual toner on the intermediate transfer belt 50 is disposed.
The printer unit 150 also includes four yellow, cyan, magenta, and black colors along the transport direction so as to face the stretched surface between the belt driving roller 14 and the cleaning facing roller 15 in the intermediate transfer belt 50. A tandem-type image forming unit 120 in which two image forming units 18 are arranged to face each other is disposed.

  An exposure device 21 is disposed above the tandem type image forming unit 120. The secondary transfer device 22 is disposed on the opposite side (below the intermediate transfer belt 50) to the side where the tandem image forming unit 120 is disposed with the intermediate transfer belt 50 interposed therebetween. In the secondary transfer device 22, a transfer conveyance belt 24 that is an endless belt is stretched around a pair of transfer conveyance support rollers 23, and one of the pair of transfer conveyance support rollers 23 is rotationally driven as a drive roller. The transfer conveyance belt 24 is driven to rotate counterclockwise in FIG. Further, the right transfer / conveyance support roller 23 and the secondary transfer counter roller 16 in FIG. 6 are in contact with each other with the intermediate transfer belt 50 and the transfer / conveyance belt 24 interposed therebetween. A contact portion with the conveyance belt 24 becomes a secondary transfer nip.

A fixing device 25 that fixes the toner image on the recording medium S is disposed on the downstream side in the conveyance direction of the recording medium S of the secondary transfer device 22 in the printer unit 150 (left side in FIG. 6). The fixing device 25 includes a heating unit 26 provided with a heater (not shown) therein, and a pressure roller 27 that is pressed by a spring (not shown) and presses against the heating unit 26 to form a nip portion as a press-contact portion. ing.
Below the secondary transfer device 22 and the fixing device 25 in the printer unit 150, a reversing device 28 for reversing the recording medium S when an image is formed on both sides of the recording medium S is disposed.

  Next, formation of a full color image (color copy) using the copying machine 100B will be described. First, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and a document is set on the contact glass 32 of the scanner 300. close up.

  When the user presses a start switch on an operation panel (not shown), when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32. As soon as the document is set on the scanner 300, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, the light from the light source is irradiated by the first traveling body 33 so that the light is reflected by the document surface, and the reflected light is reflected by the mirrors in the first traveling body 33 and the second traveling body 34, Light is received by the reading sensor 36 through the imaging lens 35. As a result, a color original (color image) is read and used as black, yellow, magenta, and cyan image information.

  Each image information of black, yellow, magenta, and cyan is transmitted to the exposure device 21, and exposure light corresponding to each image information is provided to each photoconductor 10 (Y, Y, Y) of each image forming unit 18 in the tandem type image forming unit 120. C, M, K). As a result, black, yellow, magenta, and cyan toner images are formed in each image forming unit 18.

  Note that the four image forming units 18 (Y, C, M, K) have substantially the same configuration except that the colors of the toners to be used are different from each other. Therefore, in FIG. , M, and K are omitted. The image forming unit 18 includes a drum-shaped photoconductor 10 (Y, C, M, K), and a charging device and a developing device as a charging unit around the photoconductor 10 (Y, C, M, K). , A primary transfer roller 62 as a primary transfer means, a photoconductor cleaning device, a static eliminator, and the like.

  Each image forming unit 18 (black image forming unit, yellow image forming unit, magenta image forming unit, and cyan image forming unit) in the printer unit 150 is based on the image information of each corresponding color. Images (black image, yellow image, magenta image, and cyan image) can be formed on the surface of each photoconductor 10 (Y, C, M, K).

  The black image, yellow image, magenta image, and cyan image formed by each image forming unit 18 are respectively transferred onto the intermediate transfer belt 50 that is rotationally moved by the belt driving roller 14, the cleaning facing roller 15, and the secondary transfer facing roller 16. A black image formed on the black photoconductor 10K, a yellow image formed on the yellow photoconductor 10Y, a magenta image formed on the magenta photoconductor 10M, and a cyan photoconductor 10C. Cyan images are sequentially transferred (primary transfer).

  Then, a black image, a yellow image, a magenta image, and a cyan image are superimposed on the intermediate transfer belt 50 to form a composite color image (color transfer image).

On the other hand, in the paper feeding device 200, one of the paper feeding rollers 142 is selectively rotated to feed out the recording medium S from one of the paper feeding cassettes 144 provided in multiple stages in the paper bank 143, and one sheet is separated by the separation roller 145. The paper is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the main body side paper feed path 148 in the printer unit 150, and abutted against the registration roller 49 and stopped. Alternatively, the manual feed roller 51 is rotated to feed out the recording medium S on the manual tray 54, separated one by one by the manual separation roller 52, and put into the manual feed path 53, and abutted against the registration roller 49 as described above. Stop.
The registration roller 49 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the recording medium S.

  After abutting against the registration roller 49 and stopping, the registration roller 49 is rotated in time with the synthesized color image (color transfer image) synthesized on the intermediate transfer belt 50, and the recording medium is directed toward the secondary transfer nip. S is sent out. A composite color image (color transfer image) on the intermediate transfer belt 50 is recorded by a transfer electric field formed between the transfer conveyance support roller 23 on the secondary transfer device 22 side and the secondary transfer counter roller 16 in the secondary transfer nip. Transfer (secondary transfer) is performed on the medium S, and a color image is formed on the recording medium S. The transfer residual toner on the intermediate transfer belt 50 after passing through the secondary transfer nip is cleaned by the intermediate transfer belt cleaning device 17.

The recording medium S on which the color image has been transferred is conveyed by the secondary transfer device 22 and sent to the fixing device 25 as a fixing unit. In the fixing device 25, the composite color image (color transfer image) is fixed on the recording medium S by applying heat and pressure at a nip formed by the heating unit 26 and the pressure roller 27. The
In the present embodiment, the above-described infrared heater 10 according to the present invention is used as the heating element in the heating means 26.

  The recording medium S that has passed through the fixing device 25 is given conveyance force by the conveyance roller pair 56 after fixing and reaches the position of the switching claw 55. The recording medium S is discharged by the discharge roller pair 156 by being switched in the transport direction by the switching claw 55 and stacked on the discharge tray 57. Alternatively, the conveying direction is switched by the switching claw 55 to reach the reversing device 28, where the reversing device 28 is reversed and guided to a position where it again hits the registration roller 49, and an image is also formed on the back surface at the secondary transfer nip. After fixing at 25, the paper is discharged by the discharge roller pair 156 and stacked on the paper discharge tray 57.

  According to the above-described embodiment of the image forming apparatus, fixing can be performed stably over a long period of time. That is, according to the present invention, the above-described infrared heater according to the present invention is an image forming apparatus that is provided with a fixing device as a fixing unit and performs heating, whereby image formation that can be stably performed for a longer period of time is performed. An apparatus can be provided.

1 Sealing Section 2 Terminal 2a Terminal (Third Embodiment)
2b terminal (fourth embodiment)
3 Filament (heating element)
4 Heat Dissipation Member 4a Heat Dissipation Member (First Embodiment)
4b Heat dissipation member (second embodiment)
5 shielding member 5a shielding member (fifth embodiment)
5b Shielding member (sixth embodiment)
6 Lead wire 7 Joint portion 10 Infrared heater 10K Photoconductor for black 10Y Photoconductor for yellow 10M Photoconductor for magenta 10C Photoconductor for cyan 14, 15, 16 Support roller 17 Cleaning device 18 Image forming means 20 Charging roller 21 Exposure device 22 Secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device (fixing means)
26 fixing belt 27 pressure roller 28 reversing device 30 exposure light 32 contact glass 33 first traveling body 34 second traveling body 35 imaging lens 36 reading sensors 42K, 42Y, 42M, 42C developer accommodating portions 43K, 43Y, 43M, 43C Developer supply rollers 44K, 44Y, 44M, 44C Development roller 45K Black developer 45Y Yellow developer 45M Magenta developer 45C Cyan developer 49 Registration roller 50 Intermediate transfer member 51 Roller 52 Corona charger 53 Manual feed Paper path 55 Switching claw 56 Discharging roller 57 Discharging tray 58 Separating roller 60 Cleaning device 61 Developing device 62 Transfer roller 63 Cleaning device 64 Discharging lamp 70 Discharging lamp 80 Transfer roller 90 Cleaning device 95 Recording medium 100B Image forming apparatus (copier)
120 Tandem type developing device 130 Document base 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separating roller 146 Paper feed path 147 Transport roller 148 Paper feed path 150 Copier main body 151 Manual feed tray 200 Paper feed table 300 Scanner 400 Automatic document transport Device L Exposure light

Japanese Patent No. 4523050

Claims (8)

An infrared heater comprising a heating element, a lead wire connected to the heating element, and a joint between the heating element and the lead wire,
An infrared heater comprising: a member disposed so as to be in contact with the atmosphere outside the infrared heater and having a function of radiating heat of the joint to the outside of the infrared heater.   The infrared heater according to claim 1, wherein the member having a function of radiating heat is provided in a sealing portion that seals the joint portion. A terminal connected to the lead wire;
The infrared heater according to claim 1, wherein the member having a function of radiating heat is the terminal.   The infrared heater according to claim 1, wherein the member having a function of radiating heat has an uneven shape.   The infrared heater according to any one of claims 1 to 4, wherein the member having a function of radiating heat is made of a material having a thermal conductivity of 50 [W / m · K] or more.   The infrared heater according to claim 1, further comprising a heat shielding member that shields heat transmitted from the heating element to the joint.   A fixing device comprising the infrared heater according to claim 1.   An image forming apparatus comprising the fixing device according to claim 7.