Fixing device and image forming apparatus

Abstract

The present invention relates to a fixing device and an image forming apparatus. The fixing device of an embodiment has a plurality of heat-generating bodies, a plurality of first terminals, a second terminal, a movable member, a conductive circuit, a film, and a rotating body. The heat-generating bodies are arranged in a main scanning direction and generate heat. The first terminals are electrically connected to the heat-generating bodies. The second terminal is electrically connected to a power source that supplies electric power to the heat-generating bodies. The conductive circuit is provided on a surface of the movable member. The film is a belt-shaped film that contacts the heat-generating bodies on one face and slides on the heat-generating bodies. The rotating body is capable of pressing the other face of the film and is capable of rotational driving. The conductive circuit is a circuit that electrically connects one or a plurality of the first terminals and the second terminal. A plurality of the conductive circuits are circuits that are different in combination of one or a plurality of the first terminals connected to the second terminal.

Description

TECHNICAL FIELD

[0001] Embodiments described in this specification relate to a fixing device and an image forming apparatus. BACKGROUND

[0002] In the past, in a fixing device of an image forming apparatus, a heating region is divided into a plurality of regions. A heater is separately provided in each of the divided regions, and an independent heating control circuit (for example, a triac) is provided for the heater of each region. By adopting this configuration, each appropriate region for a plurality of sheet sizes can be heated.

[0003] However, the number of regions (the number of divisions of the heating region) increases depending on the type of sheet size. Therefore, depending on the type of sheet size, the configuration of the fixing device becomes complicated, and the number of components (for example, the number of heating control circuits) can increase. SUMMARY

[0004] The fixing device of the embodiment has a plurality of heat generating bodies, a plurality of first terminals, a second terminal, a movable member, a conductive circuit, a film, and a rotating body. The heat generating bodies are arranged in a main scanning direction and generate heat. The first terminals are electrically connected to the heat generating bodies. The second terminal is electrically connected to a power source that supplies electric power to the heat generating bodies. The conductive circuit is provided on a surface of the movable member. The film is a belt-shaped film that contacts the heat generating bodies on one face and slides on the heat generating bodies. The rotating body is capable of being pressed against the other face of the film and is capable of being rotationally driven. The conductive circuit is a circuit that electrically connects one or a plurality of the first terminals and the second terminal. A plurality of the conductive circuits are circuits that are different in combination of one or a plurality of the first terminals connected to the second terminal. BRIEF DESCRIPTION OF DRAWINGS

[0005] Figure 1 is an external view showing an example of the overall configuration of the image forming apparatus 100 of the embodiment.

[0006] Figure 2 is a hardware block diagram of the image forming apparatus 100 of the embodiment.

[0007] Figure 3 is a front cross-sectional view of the fixing device 30 of the embodiment.

[0008] Figure 4 is a view showing a specific example of the heater unit 322.

[0009] Figure 5 is a view showing a specific example of the movable member 324.

[0010] Figure 6 is a view showing an example of the cross section of the heater unit 322 and the movable member 324.

[0011] Figure 7 is a diagram showing a specific example of the selected circuit pattern 63.

[0012] Figure 8 is a diagram showing a specific example of the selected circuit pattern 63.

[0013] Figure 9 is a flowchart showing a specific example of the processing of the control section 160.

[0014] Figure 10 is a diagram showing a configuration of a modification example of the movable member 324. DETAILED DESCRIPTION

[0015] Hereinafter, a fixing device and an image forming apparatus according to an embodiment will be described with reference to the drawings. Figure 1 is an external view showing a whole configuration example of an image forming apparatus 100 according to the embodiment. Figure 2 is a hardware block diagram of the image forming apparatus 100 according to the embodiment. The image forming apparatus 100 is, for example, a multifunction peripheral. The image forming apparatus 100 is provided with a display 110, a control panel 120, an image forming unit 130, a sheet storage 140, and an image reading unit 200.

[0016] The image forming apparatus 100 forms an image on a sheet using a developer such as toner. The developer is fixed on the sheet by being heated. The sheet is, for example, paper or label paper. The sheet is only required to be a sheet on which the image forming apparatus 100 can form an image.

[0017] The display 110 is an image display device such as a liquid crystal display, an organic EL (Electro Luminescence) display, or the like. The display 110 displays various information related to the image forming apparatus 100.

[0018] The image forming unit 130 forms an image on a sheet based on image information generated by the image reading unit 200 or image information received via a communication path. The image forming unit 130 is provided with, for example, a developer 10, a transfer 20, and a fixer 30. The image forming unit 130 forms an image, for example, by the following processing. The developer 10 of the image forming unit 130 forms an electrostatic latent image on a photosensitive drum based on image information. The developer 10 of the image forming unit 130 forms a visible image by causing a developer to adhere to the electrostatic latent image. A specific example of the developer is toner. Examples of the toner include a colorless toner, a non-colorless toner (normal toner), a decorative toner, and the like.

[0019] The transfer unit 20 of the image forming unit 130 transfers the visual image onto the sheet. The fuser 30 of the image forming unit 130 fuses the visual image onto the sheet by heating and pressurizing it. In addition, the sheet for forming the image can be a sheet housed in the sheet receiving section 140, or it can be a sheet supplied manually.

[0020] The sheet receiving section 140 receives the sheet for image formation in the image forming unit 130.

[0021] The storage unit 150 is configured using a storage device such as a magnetic hard disk drive or a semiconductor storage device. The storage unit 150 stores data required for the operation of the image forming apparatus 100. The storage unit 150 may also temporarily store data of images formed in the image forming apparatus 100.

[0022] The control unit 160 is configured using a processor such as a CPU (Central Processing Unit) and memory. The control unit 160 reads and executes a program pre-stored in the storage unit 150. The control unit 160 controls the operation of each device included in the image forming apparatus 100.

[0023] The image reading unit 200 reads the image information of the object being read as light and shadow. The image reading unit 200 records the read image information. The recorded image information can be transmitted to other information processing devices via a network. The recorded image information can be used by the image forming unit 130 to form an image on a sheet. The image reading unit 200 may include an ADF (Automatic Document Feeder).

[0024] Figure 3 This is a front cross-sectional view of the fuser 30 according to the embodiment. The fuser 30 according to the embodiment includes a pressure roller 31 and a film unit 32.

[0025] The pressure roller 31 is configured to press the surface of the membrane unit 32 and be able to rotate. When pressing the surface of the membrane unit 32, the pressure roller 31 forms a clamping portion 33 between itself and the membrane unit 32. The pressure roller 31 applies pressure to a visible image of the sheet that enters the clamping portion 33. When rotated, the pressure roller 31 transports the sheet along with its rotation. The pressure roller 31, for example, includes a metal core 311 and an elastic layer 312.

[0026] The metal core 311 is formed into a cylindrical shape from a metal material such as stainless steel. Both ends of the metal core 311 are supported axially to allow rotation. The metal core 311 is driven to rotate by a first drive unit 41. The first drive unit 41 is an electrically driven device, such as an electric motor. The first drive unit 41 is driven, for example, according to a control signal output from the control unit 160.

[0027] The elastic layer 312 is formed of an elastic material such as silicone rubber. The elastic layer 312 is formed on the outer peripheral surface of the metal core 311 with a certain thickness. A release layer is formed on the outer peripheral surface of the elastic layer 312. The release layer is formed of a resin material such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), for example. The hardness of the outer peripheral surface of the press roller 31 is preferably 40° to 70° under a load of 9.8 N in an ASKER-C durometer. Thus, the area of the nip 33 and the durability of the press roller 31 can be ensured.

[0028] The press roller 31 is rotationally driven by the power of the first driving section 41. If the press roller 31 rotates in a state where the nip 33 is formed, the cylindrical film 321 of the film unit 32 is driven to rotate. The press roller 31 conveys the sheet in the conveying direction by rotating in a state where the sheet is arranged in the nip 33.

[0029] The film unit 32 heats the visible image of the sheet that enters the nip 33. The film unit 32 includes the cylindrical film (cylindrical body) 321, a heater unit 322, a stay 323, and a movable member 324.

[0030] The cylindrical film 321 is formed in a cylindrical shape. The cylindrical film 321 includes, in order from the inner peripheral side, a base layer, an elastic layer, and a release layer. The base layer is formed in a cylindrical shape of a material such as nickel (Ni). The elastic layer is stacked on the outer peripheral surface of the base layer. The elastic layer is formed of an elastic material such as silicone rubber. The release layer is stacked on the outer peripheral surface of the elastic layer. The release layer is formed of a material such as PFA resin. The cylindrical film 321 is a belt-shaped film that contacts the heater unit 322 on one surface and slides on the surface of the heater unit 322.

[0031] Figure 4 is a view showing a specific example of the heater unit 322. The heater unit 322 includes a substrate (heating element substrate) 51, a plurality of first terminals 52, a second terminal 53, a plurality of heating elements 54, and a heating control circuit 55. The heater unit 322 is connected to a power supply 56.

[0032] The substrate 51 is formed of a metal material such as stainless steel, nickel, or a ceramic material such as aluminum nitride. The substrate 51 is formed in a plate shape of an elongated oblong shape, for example. The substrate 51 is arranged on the inner side in the radial direction of the cylindrical film 321. The substrate 51 takes the axial direction of the cylindrical film 321 as the long side direction.

[0033] The first terminals 52 are provided on the substrate 51 and connected to at least one of the heating elements 54. The first terminals 52 are configured to be electrically connected to the third terminals 61 by contacting the third terminals 61 provided on the movable member 324.

[0034] The second terminal 53 is provided on the substrate 51 and is connected to the heating control circuit 55. The second terminal 53 is configured to be electrically connected to the fourth terminal 62 provided on the movable member 324 by being in contact with the fourth terminal 62. If the first terminal 52 and the second terminal 53 are electrically connected to the third terminal 61 and the fourth terminal 62, respectively, a circuit including the heating control circuit 55, the one or more heat generating bodies 54, and the power supply 56 is formed. In this case, electric power is supplied from the power supply 56 to the one or more heat generating bodies 54 included in the formed circuit according to the control of the heating control circuit 55.

[0035] One end of the heat generating body 54 is connected to the first terminal 52, and the other end is connected to the power supply 56. The substrate 51 is arranged with a plurality of heat generating bodies 54 in the main scanning direction. The heat generating body 54 generates heat according to the passage of electric current. The heat generating body 54 is formed using, for example, a heat generating resistor such as silver-palladium alloy. The heat generating resistor for the heat generating body 54 can be configured using a material whose resistance value greatly changes according to temperature. Specifically, the heat generating resistor can be configured using a material whose resistance value is lower as the temperature is lower and whose resistance value is higher as the temperature is higher. For example, the heat generating body 54 can be configured using a PTC (Positive Temperature Coefficient) element.

[0036] The heating control circuit 55 supplies a part or all of the electric power output from the power supply 56 to the heat generating body 54 according to the control of the control section 160. The heating control circuit 55 can be configured using, for example, a semiconductor switching element such as a triac.

[0037] Returning to the description of the use Figure 3 The support plate 323 is formed using, for example, a copper plate material. The cross section of the support plate 323 can be formed in a U shape, for example. The both end portions of the support plate 323 in the longitudinal direction are fixed to the housing of the image forming apparatus 100. Thus, the film unit 32 is supported by the image forming apparatus 100.

[0038] The movable member 324 is configured to be moved by the driving force of the second driving section 42 and is capable of changing the position at which the heater unit 322 is in contact. Figure 5 is a view showing a specific example of the movable member 324. A plurality of circuit patterns 63 (for example, 63_1, 63_2, and 63_3) are formed on the surface of the movable member 324. Each circuit pattern 63 has one or more third terminals 61 and fourth terminals 62. In each circuit pattern 63, the one or more third terminals 61 and the fourth terminals 62 are electrically connected by being connected by a wire.

[0039] In each of the circuit patterns 63, the combination of the positions where the third terminals 61 are provided is different. For example, the circuit pattern 63_1 (first conductive circuit) has six third terminals 61 arranged at equal intervals. For example, the circuit pattern 63_2 has four third terminals 61 arranged at equal intervals. For example, the circuit pattern 63_3 (second conductive circuit) has two third terminals 61 arranged. As a specific example of the other circuit patterns 63, for example, a plurality of third terminals 61 can be arranged at different intervals in part. However, each of the third terminals 61 of each of the circuit patterns 63 is arranged to be in contact with the first terminal 52 in a case where the circuit pattern 63 is selected. Further, the fourth terminal 62 of each of the circuit patterns 63 is arranged to be in contact with the second terminal 53 in a case where the circuit pattern 63 is selected.

[0040] In Figure 5 a specific example, the movable member 324 has a cylindrical shape, and each of the circuit patterns 63 is formed on a curved surface. The movable member 324 rotates according to the driving force of the second driving unit 42, and thus the position of the curved surface in contact with the substrate 51 changes. The heating element 54 to be heated is selected by the control unit 160, and the circuit pattern 63 corresponding to the first terminal 52 of the selected heating element 54 is selected. The movable member 324 moves so that the third terminal 61 and the fourth terminal 62 of the selected circuit pattern are in contact with the first terminal 52 and the second terminal 53 of the substrate 51.

[0041] Figure 6 is a drawing illustrating an example of a cross section of the heater unit 322 and the movable member 324. The third terminal 61 and the fourth terminal 62 are subjected to a force acting in a direction away from the movable member 324 on the surface of the movable member 324. The force can be, for example, a force generated according to the material or shape of the third terminal 61 and the fourth terminal 62. The force can also be, for example, a force generated by an elastic body provided between the third terminal 61 and the fourth terminal 62 and the movable member 324.

[0042] For example, in Figure 6 the example, the height of the third terminal 61 in contact with the first terminal 52 is h1, and the height of the third terminal 61 not in contact with the first terminal 52 is h2. The third terminal 61 not in contact with the first terminal 52 maintains the height of h2 higher than h1 according to the force. On the other hand, the third terminal 61 in contact with the first terminal 52 is pressed to a position lower in height h1 by the force from the first terminal 52 toward the movable member 324. By generating such a force, the first terminal 52 and the third terminal 61 are more reliably in contact, and the electrical connection can be maintained.

[0043] Figure 7 is a drawing illustrating a specific example of the selected circuit pattern 63. In Figure 7The circuit pattern 63_1 is selected. The six respective third terminals 61 of the selected circuit pattern 63_1 are in contact with the first terminals 52. In addition, the fourth terminal 62 of the selected circuit pattern 63_1 is in contact with the second terminal 53. By making such contact, the six respective heat generating bodies 54 are connected to the power supply 56 via the heating control circuit 55. By forming such a circuit, electric power is supplied from the power supply 56 to the six respective heat generating bodies 54 to generate heat. Thus, in the Figure 7 heat for fixing is generated in the heat generating region 59_1 indicated by the dotted line.

[0044] Figure 8 is a view showing a specific example of the selected circuit pattern 63. In Figure 8 The circuit pattern 63_3 is selected. The two respective third terminals 61 of the selected circuit pattern 63_3 are in contact with the first terminals 52. In addition, the fourth terminal 62 of the selected circuit pattern 63_3 is in contact with the second terminal 53. By making such contact, the two respective heat generating bodies 54 are connected to the power supply 56 via the heating control circuit 55. By forming such a circuit, electric power is supplied from the power supply 56 to the two respective heat generating bodies 54 to generate heat. Thus, in the Figure 8 heat for fixing is generated in the heat generating region 59_3 indicated by the dotted line.

[0045] As Figure 7 and Figure 8 indicated, the heat generating region 59 varies depending on the selected circuit pattern 63.

[0046] Figure 9 is a flowchart showing a specific example of the processing of the control section 160. The control section 160 determines the sheet size based on the input image forming data and the operation in the control panel 120 (ACT 101). The control section 160 determines the heat generating region 59 based on the determined sheet size (ACT 102). For example, a table in which the heat generating region 59 is determined in advance for each sheet size can be registered in advance in the storage section 150. In this case, the control section 160 can determine the heat generating region 59 based on the table registered in the storage section 150.

[0047] The control section 160 performs the heating position control processing based on the determined heat generating region 59 (ACT 103). In the heating position control processing, the control section 160 drives the second driving section 42 to move the movable member 324 so that the circuit pattern 63 corresponding to the determined heat generating region 59 is in contact with the heater unit 322. If the movement of the movable member 324 is completed, the control section 160 starts heating by controlling the heating control circuit 55 to supply electric power to the heat generating body 54 (ACT 104). If the measured value of the temperature in the heat generating region 59 exceeds a predetermined threshold value, the control section 160 starts image formation by controlling the developer 10 and the transferor 20 (ACT 105).

[0048] In the image forming apparatus 100 configured in the above-described manner, only one circuit pattern opened in the heater unit 322 is formed. In the selection of the heating region 59, one circuit pattern 63 is selected from among the plurality of circuit patterns 63 formed in the movable member 324. Further, each terminal of the selected circuit pattern 63 is connected to each terminal of the heater unit 322, and a closed circuit is formed in the heater unit 322. Further, power is supplied from the power supply 56 only to the heating element 54 included in the closed circuit, and heating is started. Therefore, in the heater unit 322, it is not necessary to divide the circuit into a plurality of circuits. As a result, the number of heating control circuits 55 can be reduced (for example, to one), and the number of components can be reduced in the configuration of the fixing device. Further, it is not necessary to perform switching control to turn on / off the divided circuits individually, and firmware control can also be simplified.

[0049] (Modified Example)

[0050] Figure 10 is a view showing a configuration of a modified example of the movable member 324. In the above-described embodiment, as shown in Figure 5 , the movable member 324 is configured in a cylindrical shape. However, the shape of the movable member 324 is not limited to a cylinder. For example, as shown in Figure 10 , the movable member 324 can be configured using a polygonal columnar object. In the example shown in Figure 10 , the movable member 324 is formed in a hexagonal prism shape. Further, the movable member 324 does not necessarily have to be configured in a columnar shape, and for example, can be configured using a flat plate. In this case, the surface of the flat plate can be divided into a plurality of regions, and different circuit patterns 63 can be formed in each region. In this case, the second driving unit 42 can move the flat plate so that the selected circuit pattern 63 is brought into contact with the heater unit 322.

[0051] Although several embodiments have been described, these embodiments are presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included within the scope and spirit of the invention, and are included within the scope of the invention and equivalents thereof recited in the claims.

[0052] 1: image forming apparatus; 10: developer; 20: transfer device; 30: fuser; 31: pressure roller; 311: metal core; 312: elastic layer; 32: film unit; 321: cylindrical film; 322: heater unit; 323: support plate; 324: movable member; 33: nip; 41: first driving unit; 42: second driving unit; 51: substrate; 52: first terminal; 53: second terminal; 54: heat generating body; 55: heating control circuit; 56: power supply; 59: heat generating region; 61: third terminal; 62: fourth terminal; 63: circuit pattern; 110: display; 120: control panel; 130: image forming unit; 150: storage unit; 160: control unit; 200: image reading unit.

Claims

1. A fixing device, comprising: Multiple heating elements are arranged and generate heat in the main scanning direction; Multiple first terminals are electrically connected to the heating element; The second terminal is electrically connected to the power source that supplies power to the heating element; Movable parts; Multiple different conductive circuits are disposed on the surface of the movable part; A strip-shaped film, one side of which contacts the heating element, and slides on the surface of the heating element; as well as A rotating body that can be pressed against the other side of the film and can be driven to rotate. The conductive circuit is a circuit that electrically connects one or more first terminals and the second terminal. The plurality of said conductive circuits are different combinations of one or more first terminals respectively connected to the second terminal. The conductive circuit includes: One or more third terminals are configured to contact the first terminal; The fourth terminal is configured to contact the second terminal; and A wire electrically connects the third terminal and the fourth terminal.

2. The fixing device according to claim 1, wherein, The plurality of conductive circuits are circuits that correspond to the shape of the sheet forming the image.

3. The fixing device according to claim 1, wherein, The fixing device further includes a heating control circuit connected to a circuit having the plurality of first terminals, the second terminals and the plurality of heating elements.

4. The fixing device according to claim 3, wherein, The heating control circuit is located between the second terminal and the power supply.

5. The fixing device according to any one of claims 1 to 4, wherein, The movable part is cylindrical in shape, and the plurality of conductive circuits are disposed on the side of the movable part.

6. An image forming apparatus comprising: a fixing device and a control unit, The fixing device includes: Multiple heating elements are arranged and generate heat in the main scanning direction; Multiple first terminals are electrically connected to the heating element; The second terminal is electrically connected to the power source that supplies power to the heating element; Movable parts; Multiple different conductive circuits are disposed on the surface of the movable part; A strip-shaped film, one side of which contacts the heating element, and slides on the surface of the heating element; A rotating body that can be pressed against the other side of the film and can be rotated; as well as The drive unit moves the movable component. The control unit controls the driving unit. The conductive circuit is a circuit that electrically connects one or more first terminals and the second terminal. The plurality of said conductive circuits are different combinations of one or more first terminals respectively connected to the second terminal. The conductive circuit includes: One or more third terminals are configured to contact the first terminal; The fourth terminal is configured to contact the second terminal; and A wire electrically connects the third terminal and the fourth terminal.

7. The image forming apparatus according to claim 6, wherein, The control unit controls the driving unit's drive according to the shape of the sheet that becomes the object of image formation.

8. The image forming apparatus according to claim 7, wherein, The control unit selects one conductive circuit from the plurality of conductive circuits according to the shape of the sheet.

9. The image forming apparatus according to claim 8, wherein, The control unit controls the drive unit to drive the drive unit so that the third and fourth terminals of the selected conductive circuit contact the first and second terminals, respectively.

Images