JP2016090806A - Drive structure, fixing unit, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive structure in which a rotary member can freely rotate during stoppage of a driving force, a fixing unit, and an image forming apparatus.SOLUTION: A drive structure includes: a rotary member that has a cylindrical shape and rotates in the circumferential direction of the cylinder; a driving member that covers an end of the cylinder and is driven in the circumferential direction of the cylinder; a spiral member that has a spiral shape having a diameter of the inner periphery of the cylinder larger than that of the outer periphery, where one end of the spiral is connected to the driving member and the other end relative to the one end receives a force directed in the reverse direction to a driving direction of the driving member, and thereby reducing the diameter of the inner periphery to be fixed to the outer periphery of the cylinder; and a contact member that is not in contact with the other end of the spiral member when the driving member is not driven and is in contact with the other end when the driving member is driven.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a driving structure, a fixing device, and an image forming apparatus.

  Conventionally, a fixing device that thermally fixes an unfixed toner image on a sheet to the sheet and an image forming apparatus including such a fixing unit are known.

  For example, Japanese Patent Application Laid-Open No. 2004-228561 includes a spring clutch that transmits driving force to a fixing roller, and a spring clutch control unit that is set to cut off transmission of driving force when a paper jam is detected by the paper jam detection unit. A vessel is disclosed.

  Further, for example, Patent Document 2 includes a drive switching member for releasing transmission of the driving force and a drive switching member operation lever for operating the drive switching member. When jamming is performed, a drive switching operation lever is provided. A fixing device is disclosed that operates to release the drive connection.

JP-A-3-261964 JP 2002-40862 A

  In the prior art, a free rotation of the rotating member may be prevented when the drive is stopped due to a detection error or an operation error of a paper jam.

  An object of the present invention is to provide a driving structure, a fixing device, and an image forming apparatus in which a rotating member can freely rotate when driving force is stopped.

The drive structure according to claim 1 is:
A rotating member having a cylindrical shape and rotating in a circumferential direction of the cylinder;
A driving member that covers the end of the cylinder and is driven in the circumferential direction of the cylinder;
The cylinder has a spiral shape having an inner diameter larger than the outer circumference, and one end of the spiral is connected to the drive member, and the other end with respect to the one end is directed in a direction opposite to the drive direction of the drive member. A helical member that is fixed to the outer periphery of the cylinder by reducing the inner diameter by receiving force;
A contact member that is in non-contact with the other end of the spiral member in a non-driven state, and that contacts the other end when the drive member is driven;
It is provided with.

The drive structure according to claim 2 is:
The other end of the spiral member is an annular body that surrounds the outer periphery of the cylinder and faces the contact member,
The contact member is in contact with the entire circumference of the annular body when contacting the other end of the spiral member.

The drive structure according to claim 3 is:
The driving force is transmitted from the driving source of the driving member to the driving member, and is moved by a part of the driving force as the driving force is transmitted, and the contact member is moved to the other end of the helical member by the movement. A transmission member that moves to the side is provided.

The fixing device according to claim 4 is:
A rotating member having a cylindrical shape and rotating in a circumferential direction of the cylinder;
A pressure member for fixing the toner image on the surface of the recording medium by sandwiching and pressing the recording medium holding the unfixed toner image on the surface between the rotation member; and
A heat source for heating the recording medium sandwiched between the rotating member and the pressure member;
A driving member that covers the end of the cylinder and is driven in the circumferential direction of the cylinder;
The cylinder has a spiral shape having an inner diameter larger than the outer circumference, and one end of the spiral is connected to the drive member, and the other end with respect to the one end is directed in a direction opposite to the drive direction of the drive member. A helical member that is fixed to the outer periphery of the cylinder by reducing the inner diameter by receiving force;
A contact member that is in non-contact with the other end of the spiral member in a non-driven state, and that contacts the other end when the drive member is driven;
It is provided with.

An image forming apparatus according to claim 5
A rotating member having a cylindrical shape and rotating in a circumferential direction of the cylinder;
A pressure member for fixing the toner image on the surface of the recording medium by sandwiching and pressing the recording medium holding the unfixed toner image on the surface between the rotation member; and
A heat source for heating the recording medium sandwiched between the rotating member and the pressure member;
A driving member that covers the end of the cylinder and is driven in the circumferential direction of the cylinder;
The cylinder has a spiral shape having an inner diameter larger than the outer circumference, and one end of the spiral is connected to the drive member, and the other end with respect to the one end is directed in a direction opposite to the drive direction of the drive member. A helical member that is fixed to the outer periphery of the cylinder by reducing the inner diameter by receiving force;
A contact member that is in non-contact with the other end of the spiral member in a non-driven state, and that contacts the other end when the drive member is driven;
And an image forming device that forms the unfixed toner image on the surface of the recording medium;
It is provided with.

  According to the drive structure according to claim 1, the fixing device according to claim 4, and the image forming apparatus according to claim 5, the rotating member can freely rotate when the driving force is stopped.

  According to the drive structure concerning Claim 2, damage to a moving wall is suppressed compared with the case where it does not have the said annular body.

  According to the drive structure of the third aspect, the moving mechanism of the moving wall is simpler than when the transmission member is not provided.

1 is a schematic configuration diagram of a printer that is a first embodiment of an image forming apparatus of the present invention. It is the figure which showed the cross section of the fixing device and discharger in the printer 10 shown in FIG. It is sectional drawing showing the end of a heating roll. It is a figure which shows the state before the drive start in the operation | movement by which drive connection is constructed | assembled and cancelled | released. It is a figure which shows the state at the time of the drive start in the operation | movement by which drive connection is constructed | assembled and cancelled | released. It is a figure which shows the state in the drive in the operation | movement by which drive connection is constructed and cancelled | released. It is a figure which shows the state after the drive stop in the operation | movement by which drive connection is constructed | assembled and cancelled | released. It is a figure which shows the structure of the 2nd end vicinity in 2nd Embodiment. It is a figure which shows the moving mechanism of the moving wall in 3rd Embodiment. It is a figure which shows the state at the time of the drive in 3rd Embodiment. It is a figure which shows the state at the time of the drive stop in 3rd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a printer which is a first embodiment of an image forming apparatus of the present invention.

  The printer 10 shown in FIG. 1 is a monochrome printer, and the printer 10 incorporates an embodiment of a fixing device of the present invention.

  An image signal representing an image created outside the printer 10 is input to the printer 10 via a signal cable (not shown). The printer 10 includes a control unit 11 that controls the movement of each component in the printer 10, and an image signal is input to the control unit 11. In the printer 10, an image is formed based on the image signal under the control of the control unit 11.

  A paper tray 21 is provided below the printer 10, and the paper P is stored in the paper tray 21 in a stacked state. The paper tray 21 is configured to be freely drawn out for replenishing the paper P.

  The paper P in the paper tray 21 is sent to the standby roll 24 by the pickup roll 22 and the separating roll 23. The paper P that has reached the standby roll 24 is further transported after the transport timing is adjusted.

  The printer 10 includes a photoreceptor 12 that rotates in a direction indicated by an arrow A above a standby roll 24. A charger 13, an exposure device 14, a developing device 15, a transfer device 16, and a photoconductor cleaner 17 are disposed around the photoconductor 12.

  The charger 13 charges the surface of the photoconductor 12, and the exposure device 14 exposes the surface of the photoconductor 12 to form an electrostatic latent image. The electrostatic latent image is developed by the developing device 15 to form a toner image.

  Here, the standby roll 24 sends out the paper P so that the toner image on the photoconductor 12 reaches that position in accordance with the timing when it reaches the position facing the transfer device 16. The toner image on the photoconductor 12 is transferred to the fed paper P under the action of the transfer device 16.

  The toner remaining on the photoconductor 12 after the transfer of the toner image is removed from the photoconductor 12 by the photoconductor cleaner 17.

  A combination of the photoconductor 12, the charger 13, the exposure device 14, the developing device 15, and the transfer device 16 corresponds to an example of the image forming device referred to in the present invention.

The sheet P that has received the transfer of the toner image further proceeds in the direction of arrow B, and is heated and pressed by the fixing device 100 to fix the toner image on the sheet P. As a result, an image composed of a fixed toner image is formed on the paper P. The fixing device 100 corresponds to the first embodiment of the fixing device of the present invention.

  The paper P that has passed through the fixing device 100 proceeds in the direction of arrow C toward the discharge device 200, and is further sent in the direction of arrow D by the discharge device 200 to be discharged onto the paper discharge tray 18.

  FIG. 2 is a view showing a cross section of the fixing device and the discharging device in the printer 10 shown in FIG.

  The fixing device 100 includes a heating roll 101 and a pressure roll 102. The heating roll 101 is obtained by coating the outer peripheral surface of a metal cylinder with a release material, and a heat source 103 is disposed inside the heating roll 101. The pressure roll 102 is also cylindrical, and the circumferential surface of the pressure roll 102 is pressed against the circumferential surface of the heating roll 101. The sheet that has advanced in the direction of arrow B and has reached the fixing device 100 enters the contact portion between the pressure roll 102 and the heating roll 101. The sheet is sandwiched between the heating roll 101 and the pressure roll 102 at the contact portion. At this time, the sheet is in a state where the surface on which the toner image is formed faces the heating roll 101 side.

  The heating roll 101 and the pressure roll 102 rotate in the direction of arrow F while being in contact with each other. For this reason, the paper that has entered the contact portion passes through the contact portion by the rotation of the heating roll 101 and the pressure roll 102 and proceeds in the direction of arrow C toward the discharger 200. Then, during the passage, the toner image is fixed on the sheet by being heated by the heat source 103 inside the heating roll 101 and being pressurized by the pressure roll 102, and an image composed of the fixed toner image is formed. The sheet is fed from the discharger 200 in the direction of arrow D by the discharge roll 203 and discharged onto the discharge table 18.

  The heating roll 101 corresponds to an example of a rotating member according to the present invention, the pressure roll 102 corresponds to an example of a pressing member according to the present invention, and the heat source 103 corresponds to an example of a heat source according to the present invention.

  Here, details of the heating roll 101 will be described.

  FIG. 3 is a cross-sectional view showing one end of the heating roll.

  One end of the heating roll 101 is covered with a drive gear 104 that rotationally drives the heating roll 101. The drive gear 104 has teeth (not shown) arranged around it, and receives a driving force from the motor via the teeth.

  A spring 105 that functions as a clutch is provided between the inner periphery of the drive gear 104 and the outer periphery of the heating roll 101. The diameter of the inner periphery of the spring 105 is larger than the diameter of the outer periphery of the heating roll 101. The first end 105 a of the spring 105 is fixed to the inner periphery of the drive gear 104, and the first end 105 a rotates with the drive gear 104 as the drive gear 104 is driven.

  The fixing device 100 is provided with a moving wall 106 at a position facing one end of the heating roll 101. The moving wall 106 is movable in a direction of approaching and separating from the heating roll 101. The fixing device 100 is also provided with a tension spring 107 that pulls the moving wall 106 away from the heating roll 101 and a solenoid 108 that pushes the moving wall 106 closer to the heating roll 101 when energized. The solenoid 108 is energized when the drive gear 104 is driven.

  The second end 105b of the spring 105 protrudes toward the moving wall 106. When the solenoid 108 pushes the moving wall 106, the surface of the moving wall 106 contacts the second end 105b.

  The drive gear 104 corresponds to an example of a drive member according to the present invention, the spring 105 corresponds to an example of a spiral member according to the present invention, and the moving wall 106 corresponds to an example of a contact member according to the present invention. Moreover, the structure part provided with the heating roll 101 and the drive gear 104 is equivalent to 1st Embodiment of the drive structure of this invention.

  Next, the operation of establishing and releasing the drive connection between the drive gear 104 and the heating roll 101 by the spring 105 will be described in detail.

  4 to 7 show the operation of constructing and releasing the drive connection. However, for convenience of explanation, in these drawings, the drive gear is not shown, and a state in which a spring arranged inside the drive gear is visible is shown.

  FIG. 4 shows a state before starting driving, FIG. 5 shows a state when starting driving, FIG. 6 shows a state during driving, and FIG. 7 shows a state after stopping driving. ing.

  Before the start of driving, the pulling spring 107 shown in FIG. 3 pulls the moving wall 106, so that the moving wall 107 is separated from the second end 105 b of the spring 105. For this reason, the inner diameter of the spring 105 is widened, and a gap is formed between the spring 105 and the heating roll 101, and the drive connection is released. Therefore, the heating roll 101 is in a state of being freely rotated by an external force, and, for example, a paper causing a jam is easily removed.

  When driving of the drive gear is started, the solenoid 108 shown in FIG. 3 is energized, and the solenoid 108 pushes the moving wall 106 as shown in FIG. The two ends 105b are contacted.

  The first end 105a of the spring 105 rotates in the direction of arrow F in the drawing as the drive gear 104 rotates. On the other hand, the second end 105b of the spring 105 is subjected to a frictional force in the direction of arrow G in the drawing, which is opposite to the moving direction of the first end 105a, due to contact with the moving wall 106. As a result, the inner diameter of the spring 105 is reduced, and the inner periphery of the spring 105 and the outer periphery of the heating roll 101 come into contact with each other. This establishes a drive connection.

  Even during driving, the second end 105b of the spring 105 continues to contact the moving wall 106 and the driving connection is maintained. Further, since the driving force applied to the first end 105a is greater than the frictional force applied to the second end 105b, the heating roll 101 moves in the direction of arrow F in the figure while the second end 105b slides on the wall surface of the moving wall 106. Will rotate.

  When the drive is stopped, the energization of the solenoid 108 shown in FIG. 3 is cut off, so that the moving wall 106 is pulled back by the pulling spring 107 shown in FIG. As a result, the second end 105b of the spring 105 and the moving wall 106 are separated, and the second end 105b is moved by the restoring force of the spring 105, so that the inner diameter of the spring 105 is expanded. Then, the inner periphery of the spring 105 and the outer periphery of the heating roll 101 are separated from each other and the drive connection is released, and the heating roll 101 is freely rotated by an external force.

  Above, description of 1st Embodiment of this invention is complete | finished and below, 2nd Embodiment is described. Since the second embodiment is the same as the first embodiment except that the structure near the second end 105b of the spring 105 is different, the following description focuses on the structure near the second end 105b. Therefore, duplicate explanation is omitted.

  FIG. 8 is a view showing a structure near the second end of the spring in the second embodiment.

  In the second embodiment, the annular member 109 is fixed to the second end 105 b of the spring 105. The annular member 109 faces the wall surface of the moving wall 106. When the moving wall 106 moves toward the second end 105 b of the spring 105, the annular member 109 comes into contact with the moving wall 106 on the entire circumference of the annular member 109. Thereby, damage to the moving wall 106 due to friction with the second end 105b is suppressed, which contributes to extension of the device life.

  This is the end of the description of the second embodiment of the present invention, and the third embodiment will be described below. Since this third embodiment is the same as the first embodiment except that the mechanism for moving the moving wall 106 is different, the following description will focus on the moving mechanism of the moving wall 106, and a duplicate description will be given. Is omitted.

  FIG. 9 is a diagram illustrating a moving mechanism of the moving wall according to the third embodiment.

  In the third embodiment, a transmission gear 111 that transmits a driving force is provided between the gear 110 and the driving gear 104 that are driving sources. Each gear is a helical tooth. The driving force is transmitted from the driving gear 110 to the transmission gear 111, and further transmitted from the transmission gear 111 to the driving gear 104.

  Further, the transmission gear 111 is movable in the left-right direction in the figure, and an annular protrusion 112 protrudes from the outer periphery of the transmission gear 111. The annular protrusion 112 is rotatable in a state of being recessed in the groove of the moving wall 106.

  Thus, in the third embodiment, the moving mechanism of the moving wall is formed by a simple member called the transmission gear 111. The transmission gear 111 corresponds to an example of a transmission member according to the present invention.

  Next, the operation of the moving mechanism in the third embodiment will be described.

  FIG. 10 is a diagram illustrating a driving state in the third embodiment.

  At the time of driving, the driving source gear 110 rotates in the direction of arrow H in the figure, and the driving force is transmitted by meshing the helical teeth 110a of the driving source gear 110 and the helical teeth 111a of the transmission gear 111. Along with the transmission of such a driving force, a force is applied to the transmission gear 111 in the direction of arrow J in the figure. Therefore, the transmission gear 111 moves in the left direction in FIG. 9, and the moving wall 106 also moves in the left direction in FIG. 9 (that is, the direction approaching the heating roll 101) via the annular protrusion 112. As a result, the moving wall 106 comes into contact with the second end 105b of the spring, and the drive connection is established as in the first embodiment.

  FIG. 11 is a diagram illustrating a state when driving is stopped in the third embodiment.

  In the third embodiment, when the drive is stopped, the heating roll 101, the drive gear 104, and the like are integrally rotated in the direction of the arrow K in the drawing. Then, the helical teeth 104a of the drive gear 104 and the helical teeth 111a of the transmission gear 111 are in contact with each other, and a force in the direction of arrow L in the drawing is applied to the transmission gear 111. Therefore, the transmission gear 111 moves in the right direction in FIG. 9, and the moving wall 106 also moves in the right direction in FIG. 9 (that is, in the direction away from the heating roll 101) via the annular protrusion 112. As a result, the moving wall 106 moves away from the second end 105b of the spring, and the drive connection is released as in the first embodiment.

  In the third embodiment, even when the drive connection due to the inertial rotation of the heating roll 101 and the driving gear 104 does not occur, for example, the heating roll 101 and the driving are driven by a force that pulls the paper causing the jam. The drive connection is similarly released when the gear 104 rotates in the direction of arrow K in the figure.

  This is the end of the description of the third embodiment of the present invention. Hereinafter, a description will be given of a fourth embodiment obtained by modifying the third embodiment. In the fourth embodiment, the moving wall 106 does not move as in the above-described embodiments, but the drive gear 104 and the spring move toward the fixed wall provided at the position of the moving wall 106. A connection is formed. In the fourth embodiment, the fixed wall corresponds to an example of the contact member according to the present invention.

  In the fourth embodiment, the drive gear 104 and the drive source gear 110 are directly meshed with each other, and each gear is a helical tooth. The inclination direction of the helical teeth is an inclination direction in which the driving gear 104 is pushed toward the fixed wall by receiving a driving force from the gear 110 of the driving source. The driving gear 104 is inserted into one end of the heating roll 101, but is not fixed in the direction along the axis of the heating roll 101. Therefore, when the driving gear 104 is pushed during driving, it moves toward the fixed wall together with the spring. As a result, the second end 105b of the spring contacts the fixed wall to form a drive connection. Similarly to the third embodiment, the drive connection is released by rotating the heating roll 101 and the drive gear 104 by the pulling force or inertia of the sheet.

  This is the end of the description of each embodiment.

  In each of the above embodiments, a monochrome printer has been described as an example of the image forming apparatus. However, the image forming apparatus of the present invention may be a color printer, or may be a facsimile, a copier, or a multifunction machine. May be.

  In each of the above embodiments, as an example of the image forming apparatus according to the present invention, an image forming apparatus of a type that transfers a toner image formed on a photoreceptor onto a recording medium has been described. The image forming device may directly form a toner image on a recording medium.

  In each of the above embodiments, an example in which a toner image is formed by electrophotography that undergoes charging, exposure, and development is shown. However, the image forming device according to the present invention generates a toner image without forming a latent image. It may be drawn directly.

  In addition, when the electrophotographic system is adopted in the image forming device according to the present invention, the charger may be a contact type charger using a charging roll or the like, or a non-contact type using a discharge wire or the like. The charger may also be used. Further, the exposure device may use laser light as a light source, or may use LED or the like as a light source. Further, the developing device may use a so-called two-component developer in which toner and carrier are mixed, or may use a developer containing toner as a main component. The transfer unit may be a direct type transfer unit that directly transfers a toner image from the photosensitive member onto the paper, or indirectly the toner from the photosensitive member to the paper via an intermediate transfer member or the like. An indirect transfer device that transfers an image may be used.

DESCRIPTION OF SYMBOLS 10 Printer 12 Photoconductor 13 Charger 14 Exposure device 15 Developing device 16 Transfer device 100 Fixing device 101 Heating roll 102 Pressing roll 103 Heat source 104 Driving gear 105 Spring 105a First end 105b Second end 106 Moving wall 107 Pulling spring 108 Solenoid 109 Ring member 110 Drive source gear 111 Transmission gear

Claims (5)

A rotating member having a cylindrical shape and rotating in a circumferential direction of the cylinder;
A driving member that covers the end of the cylinder and is driven in the circumferential direction of the cylinder;
The cylinder has a spiral shape with an inner diameter larger than the outer circumference, and one end of the spiral is connected to the drive member, and the other end with respect to the one end is directed in a direction opposite to the drive direction of the drive member. A spiral member that is fixed to the outer periphery of the cylinder by reducing the inner diameter by receiving force;
A contact member that is in non-contact with the other end of the spiral member in a non-driven state and is in contact with the other end when the drive member is driven;
A drive structure characterized by comprising: The other end of the spiral member is an annular body that surrounds the outer periphery of the cylinder and faces the contact member;
The drive structure according to claim 1, wherein the contact member is in contact with the entire circumference of the annular body when contacting the other end of the spiral member.   The driving force is transmitted from the driving source of the driving member to the driving member, and is moved by a part of the driving force as the driving force is transmitted, and the contact member is moved to the other end of the helical member by the movement. The drive structure according to claim 1, further comprising a transmission member that moves to the side. A rotating member having a cylindrical shape and rotating in a circumferential direction of the cylinder;
A pressure member for fixing the toner image on the surface by sandwiching and pressing a recording medium holding an unfixed toner image on the surface between the rotation member;
A heat source for heating the recording medium sandwiched between the rotating member and the pressure member;
A driving member that covers the end of the cylinder and is driven in the circumferential direction of the cylinder;
The cylinder has a spiral shape with an inner diameter larger than the outer circumference, and one end of the spiral is connected to the drive member, and the other end with respect to the one end is directed in a direction opposite to the drive direction of the drive member. A spiral member that is fixed to the outer periphery of the cylinder by reducing the inner diameter by receiving force;
A contact member that is in non-contact with the other end of the spiral member in a non-driven state and is in contact with the other end when the drive member is driven;
A fixing device comprising: A rotating member having a cylindrical shape and rotating in a circumferential direction of the cylinder;
A pressure member for fixing the toner image on the surface by sandwiching and pressing a recording medium holding an unfixed toner image on the surface between the rotation member;
A heat source for heating the recording medium sandwiched between the rotating member and the pressure member;
A driving member that covers the end of the cylinder and is driven in the circumferential direction of the cylinder;
The cylinder has a spiral shape with an inner diameter larger than the outer circumference, and one end of the spiral is connected to the drive member, and the other end with respect to the one end is directed in a direction opposite to the drive direction of the drive member. A spiral member that is fixed to the outer periphery of the cylinder by reducing the inner diameter by receiving force;
A contact member that is in non-contact with the other end of the spiral member in a non-driven state and is in contact with the other end when the drive member is driven;
And an image forming device that forms the unfixed toner image on the surface of the recording medium;
An image forming apparatus comprising:

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