JP2018132753A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device capable of efficiently cooling a fixation device.SOLUTION: An image formation device of an embodiment includes a fixation device, a cooling device, a guide unit, and a control unit. The fixation device fixes a recording agent forming an image to a recording medium. The cooling device blows out air and cools the fixation device. The guide unit is rotatable and guides the recording medium for conveyance. The control unit places the guide unit at a position where the air blown out from the cooling device is directed to the fixation device.SELECTED DRAWING: Figure 5

Description

  Embodiments described herein relate generally to an image forming apparatus.

  2. Description of the Related Art Image forming apparatuses that can use decolorable toner that can be decolored are used. The image forming apparatus includes a fixing device that heats the decoloring toner. The fixing device heats the decolorable toner to the first temperature when performing the decolorable toner fixing mode in which the decolorable toner is fixed to the sheet. The fixing device heats the decoloring toner to a second temperature higher than the first temperature when performing the decoloring toner decoloring mode for decoloring the decoloring toner.

  When shifting from a mode other than the decoloring toner fixing mode to the decoloring toner fixing mode, it is necessary to lower the temperature of the fixing device. Therefore, an image forming apparatus that can efficiently cool the fixing device is desired.

JP 2006-170256 A

  An object of the present invention is to provide an image forming apparatus capable of efficiently cooling a fixing device.

  The image forming apparatus according to the embodiment includes a fixing device, a cooling device, a guide unit, and a control unit. The fixing device fixes a recording agent for forming an image on a recording medium. The cooling device blows wind to cool the fixing device. The guide portion is rotatable and guides the conveyance of the recording medium. The control unit arranges the guide unit at a position for guiding the wind blown from the cooling device to the fixing device.

1 is a perspective view of an image forming apparatus according to an embodiment. FIG. 2 is a front sectional view showing a schematic configuration of the fixing device. 1 is a block diagram showing a functional configuration of an image forming apparatus according to an embodiment. FIG. 3 is a front sectional view of the periphery of the fixing device in a state where the movable guide is disposed at a first position. FIG. 6 is a front sectional view of the periphery of the fixing device in a state where the movable guide is disposed at a second position. The perspective view of a movable guide. The top view which shows the positional relationship of the fan and HR thermistor with respect to a heat roller. The graph which shows the relationship between operation | movement of a cooling device, and the detection temperature of HR thermistor.

  Hereinafter, an image forming apparatus according to an embodiment will be described with reference to the drawings. In the present application, the XYZ directions are defined as follows. The Z direction is a vertical direction, and the X direction and the Y direction are horizontal directions. The Z direction is the vertical direction (height direction) of the image forming apparatus, and the + Z direction is the upward direction. The X direction is the front-rear direction (depth direction) of the image forming apparatus, and the + X direction is the front direction. The Y direction is the left-right direction (width direction) of the image forming apparatus.

  FIG. 1 is a perspective view of an image forming apparatus according to an embodiment. For example, the image forming apparatus 100 is a multifunction machine. The image forming apparatus 100 includes a display 110, a control panel 120, an image reading unit 200, a printer unit 130, and a sheet storage unit 140.

The image forming apparatus 100 forms an image on a sheet (recording medium) using a recording agent. The sheet is, for example, paper or label paper. A specific example of the recording agent is toner. The toner is either a toner used as a decolorable recording agent (referred to as a decolorable toner) or a toner used as a non-decolorable recording agent (referred to as a non-erasable toner).
The decoloring toner has a function of decoloring by applying energy from the outside. Being able to apply energy from the outside means applying an external stimulus such as temperature, light of a specific wavelength, or pressure. “Decolorization” in the present embodiment means to make an image formed with a color (including not only chromatic colors but also achromatic colors such as white and black) different from the background color of the paper visually invisible. Means.

  The display 110 is an image display device such as a liquid crystal display or an organic EL (Electro Luminescence) display. The display 110 displays various information regarding the image forming apparatus 100.

  The control panel 120 has a plurality of buttons. The control panel 120 accepts user operations. The control panel 120 receives an instruction for a print job using a decolored toner or a print job using a non-decolored toner. The control panel 120 receives an instruction for a decoloring job for a sheet printed with the decoloring toner. The control panel 120 outputs a signal corresponding to an operation performed by the user to the image formation control unit 50 (see FIG. 3) of the image forming apparatus 100. The display 110 and the control panel 120 may be configured as an integrated touch panel.

  The image reading unit 200 reads image information to be read as light brightness. The image reading unit 200 records the read image information.

  The printer 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 printer unit 130 forms an image by the following process, for example. The image forming unit of the printer unit 130 forms an electrostatic latent image on the photosensitive drum based on the image information. The image forming unit of the printer unit 130 forms a visible image by attaching a developer to the electrostatic latent image. The transfer unit of the printer unit 130 transfers the visible image onto the sheet. The fixing device of the printer unit 130 fixes the visible image on the sheet by heating and pressing the sheet. The sheet on which the image is formed may be a sheet stored in the sheet storage unit 140 or a manually inserted sheet.

  The sheet storage unit 140 stores a sheet used for image formation in the printer unit 130. The user accommodates or manually feeds the sheet on which the image is formed with the decoloring toner in the sheet accommodating portion 140. The user instructs a sheet erasing job on the control panel 120. As a result, the image formed on the sheet is erased and the sheet is output.

  FIG. 2 is a front sectional view showing a schematic configuration of the fixing device. The fixing device 20 can fix a decoloring toner and a non-decoloring toner that form an image on a sheet. The fixing device 20 can erase the color erasing toner. The fixing device 20 includes a heat roller (HR, heating roller, fixing roller) 21, an HR thermistor (HR temperature sensor) 24, a pressure belt unit 25, a pressure belt thermistor (pressure belt temperature sensor) 31, Have

The heat roller 21 has a cylindrical base formed of aluminum or the like. The outer peripheral surface of the heat roller 21 is covered with a release layer. The release layer is a fluorine coat layer. The release layer may be an elastic layer, a PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer) tube, or the like. The heat roller 21 incorporates an HR center lamp 22 and an HR side lamp 23 as heating elements. For example, the HR center lamp 22 and the HR side lamp 23 are halogen lamps. The HR center lamp 22 heats the central portion of the heat roller 21 in the axial direction (X direction). The HR side lamp 23 heats both ends of the heat roller 21 in the axial direction (X direction).
The HR thermistor 24 detects the temperature of the heat roller 21.

The pressure belt unit 25 includes a pressure belt 27, an outlet pressure roller 26, a pressure belt heat roller 28, and a nip pad 30.
The pressure belt 27 is an endless belt. The pressure belt 27 is wound around the outlet pressure roller 26 and the pressure belt heat roller 28.

  The outlet pressure roller 26 is formed by adhering solid rubber or the like around a metal core formed of SUS (Stainless Used Steel) or the like. The outlet pressure roller 26 is pressurized toward the heat roller 21 by a pressure mechanism (not shown).

  The pressure belt heat roller 28 has a cylindrical base formed of aluminum or the like. The outer peripheral surface of the pressure belt heat roller 28 is covered with a release layer. The pressure belt heat roller 28 incorporates a pressure belt lamp 29 as a heating element. For example, the pressure belt lamp 29 is a halogen lamp. When heat is transmitted from the heated pressure belt heat roller 28, the pressure belt 27 is heated.

  The nip pad 30 is a prismatic member. The nip pad 30 is formed by bonding silicon rubber or the like to an auxiliary sheet metal. The nip pad 30 presses the pressure belt 27 against the outer peripheral surface of the heat roller 21 from the inside of the pressure belt 27 by an independent pressure mechanism (not shown). The pressure belt 27 and the heat roller 21 are pressed against each other by the nip pad 30. There may be a sliding sheet for reducing friction between the nip pad 30 and the pressure belt 27.

  The pressure belt thermistor 31 detects the temperature of the pressure belt 27. The pressure belt thermistor 31 is installed at the center in the width direction of the pressure belt 27.

  A nip N is formed at a contact portion between the outer peripheral surface of the heat roller 21 and the outer peripheral surface of the pressure belt 27. The sheet and the toner on the sheet are heated and pressurized through a nip N between the heat roller 21 and the pressure belt 27. The sheet passing through the nip N is heated from both sides of the heat roller 21 and the pressure belt 27. As a result, the toner is fixed on the sheet.

FIG. 3 is a block diagram illustrating a functional configuration of the image forming apparatus 100 according to the embodiment.
An image formation control unit (simply referred to as a control unit) 50 has a CPU (Central Processing Unit). The control unit 50 controls the image forming apparatus 100 including temperature control of the fixing device 20.

  Input devices connected to the image formation control unit 50 are the HR thermistor 24, the pressure belt thermistor 31, various sensors 51, the control panel 120, and the communication unit 52. The HR thermistor 24, the pressure belt thermistor 31, and the various sensors 51 output signals to the control unit 50 via the A / D converter.

  The HR thermistor 24 outputs a signal indicating the surface temperature of the heat roller 21 to the control unit 50. The pressure belt thermistor 31 outputs a signal indicating the surface temperature of the pressure belt 27 to the control unit 50. Various sensors 51 measure physical quantities for controlling image formation. Various sensors 51 output a signal indicating the measured physical quantity to the control unit 50.

  The control panel 120 outputs a signal indicating an instruction from the user received in the control panel 120 to the control unit 50. For example, the control panel 120 outputs a print job instruction from the user to the control unit 50. In this case, the control unit 50 forms an image based on a print job instruction from the user.

  The communication unit 52 communicates with an external device. The communication unit 52 may perform wired communication or wireless communication with an external device. The external device is an information terminal such as a computer, for example. The communication unit 52 receives a signal indicating an instruction from the user from an external device and outputs the signal to the control unit 50.

  The output devices connected to the control unit 50 are the HR center lamp 22, the HR side lamp 23, the pressure belt lamp 29, the movable guide drive solenoid 60, the HR motor 61, the fan motor 62, the motor 63, and the high voltage power supply 64. . The control unit 50 controls the operation of each output device via the drive circuit. The drive circuit is formed using a switching circuit or a D / A (digital analog) converter.

  For example, the control unit 50 controls the temperature of the heat roller 21 by controlling the lighting time or power amount of the HR center lamp 22 and the HR side lamp 23. For example, the control unit 50 controls the temperature of the pressure belt 27 by controlling the lighting time or power amount of the pressure belt lamp 29.

  The movable guide drive solenoid 60 switches the arrangement of the movable guide 40 described later between a first position and a second position. The HR motor 61 rotates the heat roller 21 of the fixing device 20 shown in FIG. As the heat roller 21 rotates, the pressure belt 27 rotates. The fan motor 62 rotates a fan 70 described later.

  The ROM 53 is connected to the control unit 50. The ROM 53 stores a control program, control data, and the like. The RAM 54 is connected to the control unit 50. The RAM 54 stores control parameters, operation data of the image forming apparatus 100, and the like. For example, the RAM 54 stores the counted number of printed consumables.

FIG. 4 is a front sectional view of the periphery of the fixing device in a state where the movable guide is disposed at the first position. The image forming apparatus 100 includes a fixed guide 34, a guide portion (gate) 4, a reverse conveyance guide 36, a conveyance roller 38, and a fan (cooling device) 70 around the fixing device 20. The guide unit 4 includes a movable guide 40 and a movable guide drive solenoid 60 (see FIG. 3).
The fixed guide 34 and the movable guide 40 guide the conveyance of the sheet. The fixed guide 34 and the movable guide 40 are arranged in this order on the downstream side of the fixing device 20 in the sheet conveyance direction (simply referred to as the conveyance direction). The movable guide 40 is disposed between the fixing device 20 and the fan 70.

FIG. 6 is a perspective view of the movable guide. The movable guide 40 is formed of a resin material or the like. The movable guide 40 includes guide blades 42 and a connecting bar 41.
The guide blades 42 are formed in a plate shape whose thickness direction is the X direction. A notch 43 is formed at the upper end of the guide blade 42. A rotation shaft 40a (see FIG. 4) is inserted inside the notch 43. A first guide portion 44 is formed on the peripheral edge portion of the guide blade 42 in the + Y direction. The first guide portion 44 forms a first sheet conveyance path 71 (see FIG. 4). A second guide portion 46 is formed on the peripheral edge portion of the guide blade 42 in the −Y direction. The second guide portion 46 forms a second sheet conveyance path 72 (see FIG. 5). A plurality of guide blades 42 are arranged side by side in the X direction.

The connecting bar 41 is formed in a rod shape extending in the X direction. The connecting bar 41 connects the central portions of the plurality of guide blades 42. The connection bar 41 is driven by a movable guide drive solenoid 60 (see FIG. 3). The connection bar 41 rotates the movable guide 40 around the rotation shaft 40a (see FIG. 4). A wind direction changing surface 41 </ b> S is formed in the −Y direction of the connecting bar 41. As shown in FIG. 4, the −Y direction of the connecting bar 41 is on the same side as the fan 70 when viewed from the connecting bar 41. The wind direction changing surface 41 </ b> S changes the direction of the wind blown from the fan 70. The wind direction changing surface 41S is formed in a planar shape.
The movable guide 40 is formed in a comb shape by the connecting bar 41 and the plurality of guide blades 42. The movable guide 40 has a comb tooth portion 48 below.

As shown in FIG. 4, the movable guide 40 can be rotated around a rotation shaft 40a at the upper end. Thereby, the arrangement of the movable guide 40 can be switched between the first position P1 and the second position P2 (see FIG. 5). The movable guide 40 is biased to the first position P1 by a spring (not shown). The controller 50 operates the movable guide drive solenoid 60 (see FIG. 3) to move the movable guide 40 to the second position P2 (see FIG. 5) against the biasing force of the spring. In FIG. 4, the movable guide 40 is in the first position P1. The first position P <b> 1 is a position in which the sheet discharge direction is the direction of a discharge tray (not shown) of the image forming apparatus 100. In the first position P <b> 1, the lower comb tooth portion of the movable guide 40 meshes with the upper comb tooth portion of the fixed guide 34. A large gap is not formed between the movable guide 40 and the fixed guide 34. A first conveyance path 71 for the sheet is formed in the + Y direction of the movable guide 40. The sheet sent from the fixing device 20 is transported through the first transport path 71 and is discharged to a paper discharge tray of the image forming apparatus 100.
When the movable guide 40 is at the first position P1, the extended surface S of the wind direction changing surface 41S is arranged in the −Y direction of the nip N of the fixing device 20. The −Y direction of the nip N is on the same side as the fan 70 when viewed from the nip N. The extended surface S of the wind direction changing surface 41S is a surface including the wind direction changing surface 41S and extending around the wind direction changing surface 41S.

The reverse conveyance guide 36 is arranged at a predetermined interval in the −Y direction of the fixed guide 34 and the movable guide 40. A reverse conveyance path 35 is formed between the reverse conveyance guide 36 and the fixed guide 34 and the movable guide 40. The reverse conveyance path 35 conveys the sheet so that an image is formed on the back surface of the sheet.
The conveyance roller 38 is disposed at the upper end portion of the reverse conveyance path 35.

FIG. 5 is a front sectional view of the periphery of the fixing device in a state where the movable guide is disposed at the second position. In FIG. 5, the movable guide 40 is in the second position P2. The second position P2 is a position where the sheet discharge direction is the direction of the post-processing device when a post-processing device (not shown) is attached to the image forming apparatus 100. In the second position P2, the movable guide 40 is disposed so as to cross the first conveyance path 71 shown in FIG. A large gap is formed between the movable guide 40 and the fixed guide 34. A second transport path 72 is formed in the −Y direction of the movable guide 40. The sheet sent from the fixing device 20 is transported through the second transport path 72 and reaches the transport roller 38. The conveyance roller 38 discharges the sheet to the post-processing device. The conveyance roller 38 can also reverse the traveling direction of the sheet and allow the sheet to enter the reverse conveyance path 35.
When the movable guide 40 is at the second position P2, the extension surface S of the wind direction changing surface 41S is arranged in the + Y direction of the nip N of the fixing device 20. The + Y direction of the nip N is on the opposite side of the fan 70 as viewed from the nip N.

  The fan 70 takes in air from the outside of the image forming apparatus 100 and blows air out of the image forming apparatus 100. The fan 70 is disposed in the −Y direction of the reverse conveyance guide 36. The fan 70 cools the fixing device 20 (particularly the heat roller 21) with the blown wind.

FIG. 7 is a plan view showing the positional relationship between the fan and the HR thermistor with respect to the heat roller.
The image forming apparatus 100 includes a first fan 70a and a second fan 70b. The first fan 70 a is disposed at a position in the X direction corresponding to the end of the heat roller 21 in the + X direction. The first fan 70a cools the end portion (first portion S1) of the heat roller 21 in the + X direction. The second fan 70b is disposed at a position in the X direction corresponding to the central portion of the heat roller 21 and the end portion in the -X direction. The second fan 70b cools the central portion of the heat roller 21 and the end portion in the −X direction (second portion S2).

  The fixing device 20 includes a first HR thermistor 24a, a second HR thermistor 24b, and a third HR thermistor 24c. The first HR thermistor 24a detects the temperature by contacting the end of the heat roller 21 in the + X direction. The first HR thermistor 24a detects the temperature of the first part S1 of the heat roller 21. The second HR thermistor 24b contacts the center portion of the heat roller 21 in the X direction and detects the temperature. The third HR thermistor 24c detects the temperature by contacting the end of the heat roller 21 in the -X direction. The second HR thermistor 24b and the third HR thermistor 24c detect the temperature of the second part S2 of the heat roller 21.

  FIG. 8 is a graph showing the relationship between the operation of the cooling device and the detected temperature of the HR thermistor. FIG. 8 illustrates a mode in which the image forming apparatus 100 performs erasing of the erasing toner (referred to as a erasing toner erasing mode) to a mode in which the erasing toner is fixed (referred to as a erasing toner fixing mode). The case of moving to is shown. The horizontal axis in FIG. 8 is time. The vertical axis in FIG. 8 represents the detected temperature of the HR thermistor 24 and the drive signal of the fan 70. The graph B of the detected temperature of the second part S2 indicates the detected temperature of the HR thermistor 24 that becomes high out of the second HR thermistor 24b and the third HR thermistor 24c. The detected temperature of the pressure belt thermistor 31 is equal to the detected temperature of the HR thermistor 24.

  When the user instructs a decoloring toner erasing job from the control panel 120 (see FIG. 1), the image forming apparatus 100 executes the erasing toner erasing mode. The image forming apparatus 100 erases the image of the decoloring toner formed on the sheet. The image forming apparatus 100 conveys the sheet to the fixing device 20 and decolors the image by heating the decoloring toner to the decoloring temperature.

  Next, when the user instructs a print job of the decoloring toner from the control panel 120, the image forming apparatus 100 executes the decoloring toner fixing mode. The image forming apparatus 100 conveys the sheet to the fixing device 20 after forming an image on the sheet with the decoloring toner. The image forming apparatus 100 heats the erasable toner to a fixing temperature to fix the erasable toner on the sheet. Generally, the fixing temperature is lower than the decoloring temperature.

  In FIG. 8, the image forming apparatus 100 first performs a decoloring toner decoloring mode. At this time, the control unit 50 sets the temperature of the heat roller 21 to the decoloring temperature. Next, when a print job is instructed, the control unit 50 turns on the drive signals for the first fan 70a and the second fan 70b. As a result, wind blows from the first fan 70a and the second fan 70b, and the cooling operation of the fixing device 20 is started. The controller 50 rotates the heat roller 21 when cooling the fixing device 20. The heat roller 21 is cooled by rotating. As a result, the image forming apparatus 100 can efficiently cool the fixing device 20.

  The position of the movable guide 40 in the erasing toner erasing mode immediately before the cooling operation is determined by an instruction for the sheet discharge direction in the erasing job. Therefore, the previous erasing toner erasing mode may be performed with the movable guide 40 disposed at the first position P1 as shown in FIG. A large gap is not formed between the movable guide 40 and the fixed guide 34 at the first position P1. When the cooling operation is performed in this state, the wind 76 blown from the fan 70 is blocked by the movable guide 40 and the fixed guide 34. When the movable guide 40 is at the first position P1, the extended surface S of the wind direction changing surface 41S is arranged in the −Y direction of the nip N. The wind 76 hits the wind direction changing surface 41 </ b> S to change the course, and flows in the −Y direction of the extended surface S. Therefore, it becomes difficult for the wind 76 to reach the fixing device 20, and the cooling efficiency of the fixing device 20 decreases.

  Therefore, the control unit 50 arranges the movable guide 40 at the second position P2 as shown in FIG. The controller 50 outputs a drive signal to the movable guide drive solenoid 60 (see FIG. 3) to move the movable guide 40 to the second position P2 (see FIG. 5). Even when the previous erasing toner erasing mode is performed with the movable guide 40 disposed at the second position P2, the control unit 50 similarly outputs a drive signal.

  The second position P <b> 2 is a position for guiding the wind 77 blown from the fan 70 to the fixing device 20. A large gap is formed between the movable guide 40 and the fixed guide 34 at the second position P2. Therefore, the air 77 blown from the fan 70 passes through the gap between the movable guide 40 and the fixed guide 34. When the movable guide 40 is in the second position P2, the extension surface S of the wind direction changing surface 41S is arranged in the + Y direction of the nip N. The wind 76 strikes the wind direction changing surface 41 </ b> S, changes the course, and flows toward the fixing device 20 in the −Y direction of the extended surface S. Further, the wind 77 reaches the fixing device 20 through the space in the + Y direction of the fixed guide 34. Thereby, the fixing device 20 is efficiently cooled.

As shown in FIG. 8, the erasing toner fixing mode is performed by holding the fixing device 20 at a printing temperature (not shown) that is lower than the lower erasing temperature and higher than the lower fixing temperature.
The image forming apparatus 100 cools the fixing device 20 by the first fan 70a and the second fan 70b. At this time, a temperature distribution may be formed on the heat roller 21. In FIG. 8, the temperature decrease rate of the first part S1 represented by the graph A is fast, and the temperature decrease rate of the second part S2 represented by the graph B is slow. When the temperature of the first part S1 is lower than the decolorization lower limit temperature, the temperature of the second part S2 is still higher than the decolorization lower limit temperature. If the cooling by the first fan 70a and the second fan 70b is continued until the temperature of the second part S2 falls below the decolorization lower limit temperature, the temperature of the first part S1 may fall below the fixing lower limit temperature.

  Therefore, the control unit 50 stops only the operation of the first fan 70a when the temperature of the first part S1 is lower than the fan stop temperature. The fan stop temperature is set lower than the decolorization lower limit temperature and higher than the fixing lower limit temperature. The first fan 70a cools the first part S1 of the fixing device 20. By stopping the operation of the first fan 70a, the temperature drop of the first part S1 is stopped. For this reason, the temperature of the first portion S1 is maintained at a temperature lower than the decolorization lower limit temperature and higher than the fixing lower limit temperature.

  When the temperature of the first part S1 is lower than the fan stop temperature, the temperature of the second part S2 is higher than the decolorization lower limit temperature. The controller 50 continues the operation of the second fan 70b even when the temperature of the first part S1 is lower than the fan stop temperature. The second fan 70b cools the second part S2 of the fixing device 20. Thereby, the temperature fall of 2nd site | part S2 continues. Therefore, the temperature of the second part S2 falls to a temperature lower than the decolorization lower limit temperature.

  The controller 50 stops the operation of the second fan 70b when the temperature of the second part S2 is lower than the fan stop temperature. By stopping the operation of the second fan 70b, the temperature drop of the second part S2 is stopped. Therefore, the temperature of the second part S2 is maintained at a temperature lower than the decolorization lower limit temperature and higher than the fixing lower limit temperature.

  After the entire temperature of the fixing device 20 is lower than the lower limit temperature for erasing and higher than the lower limit temperature for fixing, the image forming apparatus 100 executes the erasing toner fixing mode. The position of the movable guide 40 in the erasing toner fixing mode is switched according to the instruction of the paper discharge direction in the print job.

As described in detail above, the image forming apparatus 100 according to the embodiment includes the fixing device 20, the fan 70, the movable guide 40, and the control unit 50. The fixing device 20 fixes a decoloring toner for forming an image on the sheet. The fan 70 blows wind to cool the fixing device 20. The movable guide 40 is rotatable and guides the conveyance of the sheet. The control unit 50 arranges the movable guide 40 at the second position P <b> 2 that guides the wind blown from the fan 70 to the fixing device 20.
As a result, the wind 77 blown out from the fan 70 reaches the fixing device 20 without being blocked (obstructed). Therefore, the image forming apparatus 100 can cool the fixing device 20 efficiently.

The movable guide 40 is rotatable, guides the conveyance of the sheet, and changes the direction of the wind blown from the fan 70. The control unit 50 rotates the movable guide 40 to the first position P1 and the second position P2. The cooling efficiency of the fixing device 20 is higher at the second position P2 than at the first position P1.
By rotating the movable guide 40 to the second position P2, the image forming apparatus 100 can cool the fixing device 20 efficiently. Even when the movable guide 40 is rotated to the first position P1 or when the movable guide 40 is rotated between the first position P1 and the second position, the image forming apparatus 100 causes the fixing device 20 to move. It can be cooled to some extent.

The movable guide 40 has a wind direction changing surface 41 </ b> S that changes the direction of the wind blown from the fan 70. The wind direction changing surface 41S is arranged so that the extended surface S of the wind direction changing surface 41S is disposed on the same side as the fan 70 when viewed from the nip N of the fixing device 20 when the movable guide 40 is rotated to the first position P1. It is formed. The wind direction changing surface 41 </ b> S is arranged such that when the movable guide 40 is rotated to the second position P <b> 2, the extended surface S of the wind direction changing surface 41 </ b> S is disposed on the opposite side of the fan 70 as viewed from the nip N of the fixing device 20. It is formed.
When the movable guide 40 is rotated to the first position P1, the extended surface S of the wind direction changing surface 41S is disposed on the same side as the fan 70 when viewed from the nip N of the fixing device 20. Therefore, the wind 76 blown out from the fan 70 hits the wind direction changing surface 41 </ b> S, changes the course, and hardly flows in the direction of the nip N of the fixing device 20. When the movable guide 40 is rotated to the second position P2, the extended surface S of the wind direction changing surface 41S is disposed on the opposite side of the fan 70 when viewed from the nip N of the fixing device 20. Therefore, the wind 76 blown out from the fan 70 hits the wind direction changing surface 41 </ b> S, changes the course, and easily flows in the direction of the nip N of the fixing device 20. As a result, the cooling efficiency of the fixing device 20 is higher at the second position P2 than at the first position P1.

  The movable guide 40 switches the sheet discharge direction according to the first position P1 and the second position P2. The image forming apparatus 100 guides the wind blown from the fan 70 to the fixing device 20 by using the movable guide 40 that switches the sheet discharge direction. Therefore, an increase in the cost of the image forming apparatus 100 can be prevented.

  The fixing device 20 can perform a decoloring toner fixing mode in which a decolorable toner that can be decolored is fixed to a sheet as a recording agent. The control unit 50 cools the fixing device 20 by the fan 70 when shifting from a mode other than the decoloring toner fixing mode (decoloring toner decoloring mode or non-decoloring toner fixing mode) to the decoloring toner fixing mode. The temperature of the fixing device in the decoloring toner fixing mode is lower than the temperature of the fixing device in a mode other than the decoloring toner fixing mode. The image forming apparatus 100 can efficiently cool the fixing device 20 when shifting to the decoloring toner fixing mode.

  When the control unit 50 shifts from a mode other than the color erasing toner fixing mode to the color erasing toner fixing mode, the temperature of the fixing device can fix the color erasing toner and the color erasing lower limit temperature at which the color erasing toner can be erased. When the fan stop temperature set in advance with respect to the fixing lower limit temperature is reached, the cooling of the fixing device 20 by the fan 70 is stopped. Thereby, in the decoloring toner fixing mode, the temperature of the fixing device 20 does not fall below the lower limit fixing temperature. Therefore, the image forming apparatus 100 can prevent the fixing device 20 from being overcooled.

  The fixing device 20 includes a heat roller 21 that heats the sheet, and the control unit 50 rotates the heat roller 21 when the fixing device 20 is cooled by the fan 70. The heat roller 21 is cooled by rotating. As a result, the image forming apparatus 100 can cool the fixing device 20 efficiently.

The image forming apparatus 100 according to the embodiment employs a movable guide 40 that switches the sheet discharge direction as the guide unit 4. On the other hand, the image forming apparatus 100 can switch the arrangement to the first position and the second position (position for guiding the wind blown from the fan 70 to the fixing device 20) in addition to the movable guide 40 for switching the paper discharge direction. It is possible to employ a guide portion that guides the conveyance of the sheet.
In the guide part 4 of the embodiment, the movable guide 40 is biased to the first position P1 by a spring. The control unit 50 operates the movable guide drive solenoid 60 to move the movable guide 40 to the second position P2 against the biasing force of the spring. On the other hand, the movable guide 40 may be biased to the second position P2 by a spring. In this case, the control unit 50 operates the movable guide driving solenoid 60 to move the movable guide 40 to the first position P1 against the biasing force of the spring.

The image forming apparatus 100 according to the embodiment employs a fan 70 as a cooling device. On the other hand, the image forming apparatus 100 can employ a cooling device that blows air and cools the fixing device in addition to the fan 70.
In FIG. 7, the first fan 70 a and the second fan 70 b are disposed asymmetrically with respect to the center of the heat roller 21 in the X direction. On the other hand, if there is no space restriction, the first fan 70a and the second fan 70b may be arranged symmetrically with respect to the center of the heat roller 21 in the X direction.

  As described above, the temperature of the fixing device in the erasing toner fixing mode is lower than the temperature of the fixing device in the erasing toner erasing mode. The image forming apparatus 100 according to the embodiment can efficiently cool the fixing device 20 when shifting from the erasing toner erasing mode to the erasing toner fixing mode. Generally, the temperature of the fixing device in the decoloring toner fixing mode is lower than the temperature of the fixing device in the non-decoloring toner fixing mode. The image forming apparatus 100 according to the embodiment can efficiently cool the fixing device 20 even when the non-erasable toner fixing mode is shifted to the erasing toner fixing mode.

  The temperature of the fixing device in the non-decoloring toner fixing mode may be higher than the fixing upper limit temperature (so-called high temperature offset). The image forming apparatus 100 according to the embodiment can efficiently cool the fixing device 20 even when the fixing device is cooled in order to eliminate the high temperature offset of the fixing device.

A modification of the embodiment will be described.
The image forming apparatus 100 according to the embodiment drives the fan 70 to cool the fixing device 20 when shifting from the erasing toner erasing mode to the erasing toner fixing mode. On the other hand, the image forming apparatus 100 according to the modified example drives the fan 70 to cool the fixing device 20 during each mode. Hereinafter, the case where the fan 70 is driven to cool the fixing device 20 during the decoloring toner fixing mode will be described as an example.

  When the user instructs a print job of decoloring toner from the control panel 120, the image forming apparatus 100 performs the decoloring toner fixing mode. The image forming apparatus 100 conveys the sheet to the fixing device 20 after forming an image on the sheet with the decoloring toner. The image forming apparatus 100 heats the erasable toner to a fixing temperature to fix the erasable toner on the sheet. When the sheet discharge tray is instructed as the sheet discharge direction in the print job, the image forming apparatus 100 places the movable guide 40 at the first position P1 as shown in FIG. The sheet sent from the fixing device 20 is transported through the first transport path 71 and is discharged to a paper discharge tray of the image forming apparatus 100.

  The controller 50 detects the temperature of the heat roller 21 by the HR thermistor 24 shown in FIG. 2 during execution of the print job. During the execution of the print job, the temperature of the heat roller 21 may exceed a predetermined temperature (fan driving temperature) set in advance. In this case, the control unit 50 drives the fan 70 to cool the fixing device 20. The image forming apparatus 100 cools the fixing device 20 while executing a print job for discharging the sheet to the discharge tray. That is, the control unit 50 drives the fan 70 while the movable guide 40 is disposed at the first position P1 as shown in FIG. A large gap is not formed between the movable guide 40 and the fixed guide 34 at the first position P1, but a small gap is formed. Therefore, even if the fan 70 is driven while the movable guide 40 is disposed at the first position P <b> 1, a part of the wind blown from the fan 70 reaches the fixing device 20. Accordingly, the image forming apparatus 100 can cool the fixing device 20 while performing the decoloring toner fixing mode.

The image forming apparatus 100 according to the modified example drives the fan 70 in a state where the movable guide 40 is disposed at the first position P1 as shown in FIG. On the other hand, the image forming apparatus 100 can also cool the fixing device 20 by driving the fan 70 with the movable guide 40 disposed at the second position P2 as shown in FIG.
In the image forming apparatus 100 according to the modification, the fan 70 is driven to cool the fixing device during the decoloring toner fixing mode. In contrast, the image forming apparatus 100 may drive the fan 70 to cool the fixing device 20 during the non-decolorable toner fixing mode or the decolorable toner decoloring mode other than the decolorable toner fixing mode. it can.

A first reference example will be described.
The image forming apparatus 100 according to the embodiment and the modification thereof drives the fan 70 to cool the fixing device 20. On the other hand, the image forming apparatus 100 of the reference example drives the fan 70 to cool other than the fixing device 20. The image forming apparatus 100 of the first reference example drives the fan 70 to cool the fan 70 itself.

  During the erasing toner erasing mode, the fan 70 itself may become hot. In this case, the control unit 50 drives the fan 70 to cool the fan 70 itself. The control unit 50 detects the temperature of the fan 70 with a fan temperature sensor, and drives the fan 70 when the temperature of the fan 70 becomes equal to or higher than a predetermined temperature. The wind blown from the fan 70 hits the movable guide 40 shown in FIG. As a result, the image forming apparatus 100 can drive the fan 70 to cool the fan 70 itself.

A second reference example will be described.
The image forming apparatus 100 of the second reference example drives the fan 70 to cool the sheet.
In the decoloring toner decoloring mode, the image forming apparatus 100 conveys the sheet to the fixing device 20 and heats the decoloring toner to the decoloring temperature to decolor the image. At this time, the control unit 50 sets the temperature of the heat roller 21 to the decoloring temperature. In general, since the decoloring temperature is higher than the fixing temperature, the decolored toner after decoloring remaining on the sheet becomes high temperature. When this sheet is discharged and accumulated on a discharge tray or the like, a phenomenon (sticking) occurs in which adjacent sheets are bonded via the decoloring toner.

  Therefore, the image forming apparatus 100 drives the fan 70 to cool the sheet during the erasing toner erasing mode. The control unit 50 detects the temperature of the sheet with the sheet temperature sensor, and drives the fan 70 when the temperature of the sheet becomes equal to or higher than a predetermined temperature. For example, as shown in FIG. 4, the controller 50 drives the fan 70 while the movable guide 40 is disposed at the first position P1. As a result, the image forming apparatus 100 cools the sheet sent from the fixing device 20 and conveyed along the first conveyance path 17. As described in the modification, a large gap is not formed between the movable guide 40 and the fixed guide 34 at the first position P1, but a small gap is formed. Therefore, even if the fan 70 is driven with the movable guide 40 placed at the first position P <b> 1, part of the wind blown from the fan 70 reaches the first conveyance path 17. Accordingly, the image forming apparatus 100 can cool the sheet while performing the erasing toner erasing mode.

  The image forming apparatus 100 of the second reference example drives the fan 70 with the movable guide 40 disposed at the first position P1 as shown in FIG. 4 to cool the sheet conveyed along the first conveyance path 17. did. In contrast, the image forming apparatus 100 drives the fan 70 with the movable guide 40 disposed at the second position P2 as shown in FIG. 5 to cool the sheet conveyed along the second conveyance path 72. You can also. The image forming apparatus 100 of the reference example drives the fan 70 to cool the fan 70 itself or the sheet. On the other hand, the image forming apparatus 100 can drive the fan 70 to cool other members.

  According to at least one embodiment described above, when the fixing device 20 is cooled by the fan 70, the control unit that arranges the movable guide 40 at the second position P2 that guides the air blown from the fan 70 to the fixing device 20. By having 50, the fixing device 20 can be efficiently cooled.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  N ... nip, P1 ... first position, P2 ... second position, S ... extension surface, 20 ... fixing device, 21 ... heat roller (heating roller), 40 ... movable guide (guide portion), 41S ... wind direction changing surface, 50: Image formation control unit (control unit), 70, 70a, 70b: Fan (cooling device).

Claims (7)

A fixing device for fixing a recording agent for forming an image on a recording medium;
A cooling device for blowing the wind to cool the fixing device;
A rotatable guide part for guiding the conveyance of the recording medium;
A control unit for rotating the guide unit to a position for guiding the wind blown from the cooling device to the fixing device;
Image forming apparatus. A fixing device for fixing a recording agent for forming an image on a recording medium;
A cooling device for blowing the wind to cool the fixing device;
A rotatable guide unit that guides the conveyance of the recording medium and changes the direction of the air blown from the cooling device;
And a control unit that rotates the guide unit to a first position and a second position where the cooling efficiency of the fixing device is higher than that of the first position.
Image forming apparatus. The guide portion has a wind direction changing surface for changing the direction of the wind blown from the cooling device,
The wind direction changing surface is formed such that when the guide portion is rotated to the first position, an extended surface of the wind direction changing surface is disposed on the same side as the cooling device when viewed from the nip of the fixing device. And
The wind direction changing surface is formed such that when the guide portion is rotated to the second position, an extended surface of the wind direction changing surface is disposed on the opposite side of the cooling device when viewed from the nip of the fixing device. To be
The image forming apparatus according to claim 2. The guide unit switches a discharge direction of the recording medium;
The image forming apparatus according to claim 1. The fixing device can implement a decoloring toner fixing mode in which a decolorable decolorable toner is fixed to the recording medium as the recording agent,
The control unit cools the fixing device by the cooling device when shifting from the mode other than the color erasing toner fixing mode to the color erasing toner fixing mode.
The image forming apparatus according to claim 1. When the control unit shifts from a mode other than the decoloring toner fixing mode to the decoloring toner fixing mode, the temperature of the fixing device is set to a decoloring lower limit temperature at which the decoloring toner can be decolored and the decoloring Stopping the cooling of the fixing device by the cooling device when a cooling device stopping temperature set in advance between the fixing lower limit temperature at which the toner can be fixed is reached,
The image forming apparatus according to claim 5. The fixing device has a heating roller for heating the recording medium,
The control unit rotates the heating roller when the fixing device is cooled by the cooling device.
The image forming apparatus according to claim 1.

Images