This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2016-139762 filed Jul. 14, 2016.
The present invention relates to a fixing device and an image forming apparatus.
According to an aspect of the invention, there is provided a fixing device including a heating member that heats a recording medium having an image while transporting the recording medium by rotating; a measuring member that measures a temperature of the heating member and includes a body member, and a cantilever member whose base end is fixed to the body member and whose free end is in contact with the heating member; and a supporting member that supports the measuring member and includes a contact portion, the contact portion being in contact with a base portion of the cantilever member.
An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein:
An image forming apparatus according to an exemplary embodiment of the present invention will now be described with reference to
Overall Configuration
Referring to
Container
The container 14 includes a container member 26 that is drawable from an apparatus body 10A of the image forming apparatus 10 toward the near side in the apparatus-depth direction. The sheet members P are stacked in the container member 26. The container member 26 is provided with a pickup roller 30 that picks up one of the sheet members P stacked in the container member 26 and feeds the sheet member P into a transport path 28 running through the transporting section 16.
Transporting Section
The transporting section 16 is provided with plural pairs of transporting rollers 32 that transport the sheet member P received from the container 14 along the transport path 28.
The transporting section 16 further includes a reverse transport path 34 along which the sheet member P having an image on the front side thereof is transported if another image is to be formed on the back side of the sheet member P. The reverse transport path 34 is provided with a pair of transporting rollers 58 that transports the sheet member P along the reverse transport path 34.
Image Forming Section
The image forming section 20 includes four image forming units 18Y, 18M, 18C, and 18K provided for yellow (Y), magenta (M), cyan (C), and black (K), respectively. Hereinafter, the suffixes Y, M, C, and K may be omitted if there is no need to distinguish the four units 18Y, 18M, 18C, and 18K from one another by their colors. The image forming units 18 are each attachable to and detachable from the apparatus body 10A.
Each of the image forming units 18 includes an image carrier 36, a charging member 38 that charges the surface of the image carrier 36, an exposure device 42 that applies exposure light to the charged image carrier 36 and thus forms an electrostatic latent image on the image carrier 36, and a developing device 40 that develops and visualizes the electrostatic latent image into a toner image.
The image forming section 20 further includes an endless transfer belt 22 that rotates in a direction of arrow A illustrated in
The fixing device 50 will be described in detail later.
Operation of Image Forming Apparatus
The image forming apparatus 10 forms an image as follows.
First, in each of the image forming units 18, the charging member 38 to which a voltage is applied charges the surface of the image carrier 36 uniformly with a predetermined negative potential. Subsequently, the exposure device 42 applies exposure light to the charged surface of the image carrier 36 on the basis of image data received from an external device.
Thus, an electrostatic latent image based on the image data is formed on the surface of the image carrier 36. Then, the developing device 40 develops and visualizes the electrostatic latent image into a toner image. Toner images thus formed on the surfaces of the four image carriers 36 are transferred to the transfer belt 22 by the respective first transfer rollers 44.
Meanwhile, a sheet member P is fed from the container member 26 into the transport path 28 by the pickup roller 30 and is transported to a transfer position T where the transfer belt 22 is in contact with the second transfer roller 46. At the transfer position T, the sheet member P passes through the nip between the transfer belt 22 and the second transfer roller 46, whereby the toner images on the transfer belt 22 are transferred to the front of the sheet member P.
The toner images thus transferred to the front side of the sheet member P are fixed on the sheet member P by the fixing device 50, whereby a finished image is obtained. Then, the sheet member P having the finished image is discharged to the outside of the apparatus body 10A.
If another image is to be formed on the back side of the sheet member P, the sheet member P having the finished image on the front side thereof is fed into the reverse transport path 34, where the sheet member P is turned upside down, and is further fed into the transport path 28. A process of forming another image on the back side of the sheet member P is the same as the above process of forming an image on the front side of the sheet member P.
Configuration of Featured Element
The configuration of the fixing device 50 will now be described.
Referring to
The fixing device 50 further includes a first measuring member 92, and a first supporting member 104 that supports the first measuring member 92. The first measuring member 92 measures the temperature of a heating roller 54, which is an exemplary heating member included in the fixing member 52. The first measuring member 92 is an exemplary measuring member. The first supporting member 104 is an exemplary supporting member.
The fixing device 50 further includes a second measuring member 112, and a second supporting member 124 that supports the second measuring member 112. The second measuring member 112 measures the temperature of a pressing roller 56, which is an exemplary pressing member included in the fixing member 52. The second measuring member 112 is another exemplary measuring member. The second supporting member 124 is another exemplary supporting member.
Fixing Member
The heating roller 54 included in the fixing member 52 is provided thereinside with a heat source and has a columnar shape. The heating roller 54 rotates in a direction of arrow R1 illustrated in
In such a configuration, the sheet member P having the toner images transferred thereto is transported through the nip between the heating roller 54 that is rotating and the pressing roller 56. Thus, the fixing member 52 fixes the toner images on the sheet member P.
Guiding Portion
The guiding portion 70 is positioned on the downstream side with respect to the fixing member 52 in the direction of transport of the sheet member P (hereinafter referred to as “the sheet-transporting direction”). The guiding portion 70 includes a first guiding portion 72 provided on the side of the heating roller 54, and a second guiding portion 74 provided across the transport path 28 from the first guiding portion 72.
First Guiding Portion
Referring to
The pair of guiding plates 76, which are made of a resin material, are positioned near a central part, in the apparatus-depth direction, of the heating roller 54 and face each other in the apparatus-depth direction. The plural guiding plates 78, which are also made of a resin material, are provided on two outer sides of the pair of guiding plates 76 in the apparatus-depth direction. The guiding plates 76 are exemplary guiding members.
Referring to
The guiding plates 76 each include a contact portion 76B on a side thereof opposite the guiding edge 76A in the apparatus-width direction. The contact portion 76B extends in a direction away from the transport path 28 and is in contact with a base portion of a cantilever member 96, which will be described later. The guiding plates 76 differ from the guiding plates 78 in including the contact portions 76B.
Second Guiding Portion
Referring to
The pair of guiding plates 82 are positioned near a central part, in the apparatus-width direction, of the pressing roller 56 and face each other in the apparatus-depth direction. The plural guiding plates 84 are provided on two outer sides of the pair of guiding plates 82 in the apparatus-depth direction.
Referring to
The guiding plates 82 differ from the guiding plates 84 in including the contact portions 82B.
First Measuring Member and First Supporting Member
Referring to
The first measuring member 92 is a thermistor and includes a body member 94 and the cantilever member 96 whose base end is fixed to the body member 94. The cantilever member 96 extends downward from the body member 94. As illustrated in
The cantilever member 96 is made of plate metal. The free end of the cantilever member 96 is in contact on the front side thereof with the surface of the heating roller 54, whereby the cantilever member 96 is bent. The cantilever member 96 is provided at the free end thereof and on the back side thereof with an element 98 and a wiring line 100 (see
The first supporting member 104 is formed of resin. When seen in the apparatus-depth direction, the first supporting member 104 is provided across the body member 94 from the guiding plates 76 and is fixed to the housing 50A. The first supporting member 104 includes a pair of contact portions 104B extending toward the cantilever member 96 and being in contact with the back side of the base portion of the cantilever member 96. Thus, the cantilever member 96 is held between the pair of contact portions 104B of the first supporting member 104 and the contact portions 76B of the pair of guiding plates 76.
As illustrated in
In such a configuration, the first measuring member 92 measures the temperature of the heating roller 54 by detecting the resistance value of the element 98.
Second Measuring Member and Second Supporting Member
Referring to
The second measuring member 112 is a thermistor and includes a body member 114 and the cantilever member 116 whose base end is fixed to the body member 114. The cantilever member 116 extends downward from the body member 114. As illustrated in
The cantilever member 116 is made of plate metal. The free end of the cantilever member 116 is in contact on the front side thereof with the surface of the pressing roller 56, whereby the cantilever member 116 is bent. The cantilever member 116 is provided at the free end thereof and on the back side thereof with an element 118 and a wiring line 120 (see
The second supporting member 124 is formed of resin. When seen in the apparatus-depth direction, the second supporting member 124 is provided across the body member 114 from the guiding plates 82 and is fixed to the housing 50A. The second supporting member 124 includes a pair of contact portions 124B extending toward the cantilever member 116 and being in contact with the back side of the baes portion of the cantilever member 116. Thus, the cantilever member 116 is held between the pair of contact portions 124B of the second supporting member 124 and the contact portions 82B of the pair of guiding plates 82.
The second supporting member 124 has a screw hole 124A. A screw 122 is inserted into the through hole 114A of the body member 114 and is screwed into the screw hole 124A, whereby the second measuring member 112 is supported by the second supporting member 124.
In such a configuration, the second measuring member 112 measures the temperature of the pressing roller 56 by detecting the resistance value of the element 118.
Functions
An overall function of the fixing device 50, a function of the first measuring member 92 of the fixing device 50, and a function of the second measuring member 112 of the fixing device 50 will now be described.
Overall Function
Referring to
The guiding plates 76 and 78 and the guiding plates 82 and 84 guide the sheet member P, transported by the heating roller 54 and the pressing roller 56, toward the downstream side in the sheet-transporting direction.
First Measuring Member
The first measuring member 92 measures the temperature at the surface of the heating roller 54 that is rotating. Specifically, the front side of the free end of the cantilever member 96 having the element 98 at the back thereof is brought into contact with the surface of the heating roller 54, whereby the heat of the heating roller 54 is transferred to the element 98 through the cantilever member 96. Consequently, the resistance value of the element 98 changes. Thus, the first measuring member 92 measures the temperature of the heating roller 54. In such a configuration, a so-called stick-slip phenomenon may occur between the heating roller 54 that is rotating and the cantilever member 96. In the stick-slip phenomenon, a combination of a frictional force generated between the surface of the heating roller 54 and the surface of the cantilever member 96 and a rotational force of the heating roller 54 repeatedly causes sticking and slipping between the surface of the heating roller 54 and the surface of the cantilever member 96.
In a known case where the contact portions 76B and the contact portions 104B that are in contact with the base portion of the cantilever member 96 are not provided, the stick-slip phenomenon causes the cantilever member 96 to vibrate in the direction of the thickness of the cantilever member 96.
According to the present exemplary embodiment, the guiding plates 76, which are known components, include the respective contact portions 76B that are in contact with the base portion of the cantilever member 96, and the first supporting member 104, which is also a known component, includes the contact portions 104B that are in contact with the base portion of the cantilever member 96.
Moreover, the cantilever member 96 is held between the contact portions 76B and the contact portions 104B.
Furthermore, the guiding plates 76 including the contact portions 76B are made of a resin material having a lower coefficient of heat transfer than metal materials.
Furthermore, the first supporting member 104 including the contact portions 104B is made of a resin material having a lower coefficient of heat transfer than metal materials.
Second Measuring Member
The second measuring member 112 measures the temperature at the surface of the pressing roller 56 that is rotating. Specifically, the front side of the free end of the cantilever member 116 having the element 118 at the back thereof is brought into contact with the surface of the pressing roller 56, whereby the heat of the pressing roller 56 is transferred to the element 118 through the cantilever member 116. Consequently, the resistance value of the element 118 changes. Thus, the second measuring member 112 measures the temperature of the pressing roller 56. In such a configuration, a so-called stick-slip phenomenon may occur between the pressing roller 56 that is rotating and the cantilever member 116.
In a known case where the contact portions 82B and the contact portions 124B that are in contact with the base portion of the cantilever member 116 are not provided, the stick-slip phenomenon causes the cantilever member 116 to vibrate in the direction of the thickness of the cantilever member 116.
According to the present exemplary embodiment, the guiding plates 82, which are known components, include the respective contact portions 82B that are in contact with the base portion of the cantilever member 116, and the second supporting member 124, which is also a known component, includes the contact portions 124B that are in contact with the base portion of the cantilever member 116.
Moreover, the cantilever member 116 is held between the contact portions 82B and the contact portions 124B.
Furthermore, the guiding plates 82 including the contact portions 82B are made of a resin material having a lower coefficient of heat transfer than metal materials.
Furthermore, the second supporting member 124 including the contact portions 124B is made of a resin material having a lower coefficient of heat transfer than metal materials.
While a specific exemplary embodiment of the present invention has been described in detail above, the present invention is not limited to the above exemplary embodiment. It is obvious for those skilled in the art that various other embodiments are conceivable within the scope of the present invention. For example, while the above exemplary embodiment concerns a case where both the contact portions 76B and the contact portions 104B are in contact with the base portion of the cantilever member 96, at least one of the contact portions 76B and the contact portions 104B only need to be in contact with the base portion of the cantilever member 96. In that case, however, only the effect produced by the contact portions 76B or 104B that are in contact with the cantilever member 96 is exerted.
While the above exemplary embodiment concerns a case where both the contact portions 82B and the contact portions 124B are in contact with the base portion of the cantilever member 116, at least one of the contact portions 82B and the contact portions 124B only need to be in contact with the base portion of the cantilever member 116. In that case, however, only the effect produced by the contact portions 82B or 124B that are in contact with the cantilever member 116 is exerted.
Although not specifically described in the above exemplary embodiment, since the above exemplary embodiment employs the contact portions 76B and the contact portions 104B that are in contact with the base portion of the cantilever member 96, the natural frequency of the cantilever member 96 is changed.
Although not specifically described in the above exemplary embodiment, since the above exemplary embodiment employs the contact portions 82B and the contact portions 124B that are in contact with the base portion of the cantilever member 116, the natural frequency of the cantilever member 116 is changed.
While the heating roller 54 according to the above exemplary embodiment is a columnar member, the heating roller 54 may be a belt-type member.
While the pressing roller 56 according to the above exemplary embodiment is a columnar member, the pressing roller 56 may be a belt-type member.
While the first measuring member 92 according to the above exemplary embodiment is provided near the central part, in the apparatus-depth direction, of the heating roller 54, the first measuring member 92 may be provided at an end, in the apparatus-depth direction, of the heating roller 54.
While the second measuring member 112 according to the above exemplary embodiment is provided near the central part, in the apparatus-depth direction, of the pressing roller 56, the second measuring member 112 may be provided at an end, in the apparatus-depth direction, of the pressing roller 56.
While the above exemplary embodiment employs the fixing device 50 including the guiding portion 70 that guides the sheet member P to be transported, the guiding portion 70 may be included in another device.
While the above exemplary embodiment employs the second measuring member 112 that measures the temperature of the pressing roller 56, the second measuring member 112 may be omitted if there is no need to measure the temperature of the pressing roller 56.
The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Number | Date | Country | Kind |
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2016-139762 | Jul 2016 | JP | national |
Number | Name | Date | Kind |
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7082283 | Fujita | Jul 2006 | B2 |
7113716 | Tomatsu | Sep 2006 | B2 |
8886090 | Kawata | Nov 2014 | B2 |
9188916 | Murakami | Nov 2015 | B2 |
Number | Date | Country |
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2003-015071 | Jan 2003 | JP |
2003-075760 | Mar 2003 | JP |
Number | Date | Country | |
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20180017906 A1 | Jan 2018 | US |