JP5365114B2 - Crimp release cam device and image forming apparatus using the press release cam device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crimp release cam device which reduces the changes in the rotation torque required for rotating a cam member, when crimping and releasing of a pressing member and a pressed member are performed, using a cam member and which restrains partial abrasion of the cam member and the counterpart member. <P>SOLUTION: The cam member has a shape to release crimping of the pressing member and the pressed member, when an energizing member is regulated by an energizing means regulation part while the cam member has a shape to crimp the pressed member and the pressed member, when the energizing means is not regulated. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a pressure-release releasing cam device using a cam member for pressure bonding and release of a pressure member and a member to be pressed, and an image forming apparatus using the pressure-release releasing cam device.

  The pressure member and the member to be pressed are pressure-bonded, for example, a toner image is formed on an image carrier such as a photosensitive drum using an electrophotographic method, and the toner image formed on the photosensitive drum is transferred to a sheet. There is fixing means for fixing later.

  As the fixing means, a heat fixing method using a mechanism for pressing a pressure roll is generally used for a heating roll having a built-in heating source. In order to set a predetermined nip pressure between the two fixing rolls, a pressure roll is supported by a spring against the heating roll supported by the frame of the fixing device, and the pressure is applied by the spring. A means for pressing the roll is used.

  Alternatively, a pressure fixing unit that fixes a toner image transferred to paper without using heat only by pressure is also known.

  Furthermore, a cloth fixing device that fixes an image after printing an image on the cloth while drying the cloth is known. This is one in which a pressure roll is pressed from the outside of the fabric to a heating roll having a built-in heating source to be dried and fixed.

  Here, a fixing device used in an image forming apparatus using an electrophotographic method will be described as an example. As disclosed in Patent Document 1, a nip pressure is set as means for pressing a pressure roll. A device combining a spring and a cam member for releasing the nip pressure is used (see FIG. 8). In FIG. 8, the heating roll 21 provided with a heating source therein and the pressure roll 31 are arranged to face each other.

  In FIG. 8, the pressure roll 31 is supported by a roll support arm 55, one end of the roll support arm 55 is supported on the frame of the fixing device 11 via a fulcrum 61, and the other end and the support frame 91. A tension setting spring 81 is arranged between the pressure roll 31 and the pressure roll 31 toward the heating roll 21 by the spring 81. Further, in order to release the nip pressure between the two rolls, a cam member 15 is disposed. By driving the cam member via the cam shaft 17, the roll support arm 51 is moved to a fulcrum 61. Then, the pressure roll 31 is moved away from the heating roll 21 by swinging in the clockwise direction against the force of the spring 81. Only when the fixing device 11 performs the fixing action, the pressing action by the cam member is released, and the nip pressure is set by the spring 81.

Further, in Patent Document 2, the cam member is configured with a cam surface having a multidimensional curve, and the torque for driving the cam member is released in a state where the nip pressure is released between both rolls. It is configured not to increase. Even when pressed at all positions on the cam surface, the pressure roll can be pushed down in a state that requires substantially the same rotational torque, so that the motor required for driving the cam member Since the driving force can be reduced, a technology that can cope with a large fixing device has been disclosed.
JP-A-2-282773 Japanese Patent Laid-Open No. 5-1888821

  The published patent document described above suppresses an increase in rotational torque that rotates the cam member only by providing a plurality of shapes on the peripheral surface of the cam member. However, in an image forming apparatus having a large number of copies per hour, it is necessary to apply or release a very large pressure on the fixing unit. Therefore, sufficient torque reduction cannot be achieved only with the shape of the cam member.

  The present invention reduces fluctuations in rotational torque required to rotate the cam member when the pressure member and the member to be pressed are pressed and released using the cam member. It is an object of the present invention to provide a press release cam device and an image forming apparatus using the press release cam device that reduce partial wear of the members.

The above object can be achieved by the following configuration. That is,
1. A pressurized member;
A pressure member that is disposed at a position facing the member to be pressed and moves in the direction of the member to be pressed; and
Urging means for urging the pressing member in the direction of the pressed member;
An urging means restricting portion for restricting a displacement amount of the urging means;
A pressure unit having at least the pressure member, the urging means, and the urging means regulating portion;
A cam member that moves the pressure unit in the direction of the member to be pressed by rotating, and presses and releases the pressure member and the member to be pressed;
The pressure unit is moved in the direction of the pressed member while the displacement amount of the urging means is regulated until the pressing member is crimped to the pressed member after the cam member is rotated. Let
When the cam member is rotated so that the pressure member is crimped to the member to be pressurized, and the pressure unit is moved in the direction of the member to be pressurized, the displacement amount of the urging means is restricted. The action of releasing and urging the pressing member in the direction of the member to be pressed by the urging means,
When the rotational speed of the cam member is constant, the cam member has a pressure when the pressure member is pressed against the member to be pressurized and the pressure unit is moved in the direction of the member to be pressurized. A pressure-release releasing cam device having a cam shape that is slower than a speed at which the pressure unit is moved until the pressure member is pressure-bonded to the member to be pressed.
2. 2. The pressure-bonding release cam device according to claim 1, wherein a contact roller that rotates in contact with the cam member is provided in the pressure unit.
3 . When releasing the pressure bonding between the pressure member and the member to be pressurized, the pressure unit is rotated in a direction opposite to the rotation direction of the cam member when moving the pressure unit in the direction of the member to be pressurized. The crimp release cam device according to 1 or 2, characterized in that:
4 . The pressure unit is
A pressure member supporting member that supports the pressure member and is inserted between the urging unit regulating unit and the urging unit;
A support part guide member for guiding the pressure part support member to move in the direction of the member to be pressed;
An urging means supporting member that supports at least the urging means and the support portion guide member;
Have
The pressure-release releasing cam device according to any one of claims 1 to 3, wherein the pressure member and the member to be pressed are in a roll shape.
5 . Pinch release cam device according to any one of 1 to 4 is a fixing device, an image forming apparatus characterized by using the pinch release cam device.

  According to the present invention, the displacement amount of the urging means for urging the pressure member is regulated until the pressure member is crimped to the member to be pressurized, and the urging means is regulated after the pressure member is crimped. Because the configuration is such that it deviates from the biasing means restricting portion, and the speed required after crimping the cam member is slower than the speed required for crimping, fluctuations in rotational torque required to rotate the cam member And partial wear of the cam member and the counterpart member can be suppressed.

  An embodiment of the present invention will be described. In addition, although this invention is demonstrated based on embodiment of illustration, this invention is not restricted to this embodiment. In addition, the following assertive description in the embodiment of the present invention shows the best mode, and does not limit the meaning or technical scope of the terms of the present invention.

  FIG. 1 is a side view showing a crimp release cam device 1 of the present invention, and FIG. 2 is an exploded perspective view thereof. Reference numeral 2 denotes a member to be pressed in the form of a roller, and the member to be pressed 2 is pivotally supported by the housing F of the pressure release cam device 1 so as to be rotatable via a bearing J1 (see FIG. 2). ). A pressure member 3 having a roller shape for pressing the member to be pressed 2 is provided at a position facing the member to be pressed 2. Reference numeral 4 denotes a pressurizing portion support member for supporting the pressurizing member 3, and supports the shafts 301 at both ends of the pressurizing member 3 so as to be rotatable.

  Further, support portion guide members 5 as guide members for sliding the pressure portion support member 4 in the vertical direction are provided at both ends of the pressure portion support member 4.

  Furthermore, it has an urging means support member 7 as a support plate for supporting the pressure member 3, the pressure portion support member 4, and the support portion guide member 5. These are configured as a pressure unit 10.

  The support portion guide member 5 has an urging means regulating portion 51 having a stepped shape at one end, and the other end is fixed to the urging means support member 7. As shown in FIGS. 1 and 2, a biasing means 6 that biases the pressing member 3 is inserted into the support portion guide member 5, and the biasing means 6 is compressed and locked by a locking member 52. Yes.

  Further, the biasing means support member 7 is provided with a contact roller 9 that comes into contact with a cam surface of a cam member 8 described later. The contact roller 9 is for reducing contact resistance with the cam member 8. As the cam member 8 rotates, the urging means support member 7 in the pressure unit 10 is raised so that the pressure member 3 presses the member 2 to be pressed.

  The cam member 8 is pivotally supported by a cam member mounting portion provided on the housing F, and is rotated by a stepping motor M1 via a gear provided on the rotation shaft. The stepping motor M1 can rotate by a predetermined angle by receiving a predetermined pulse signal from a control means (not shown).

  Next, the cam member 8 will be described. FIG. 3 is a diagram showing the shape of the cam member 8, and FIG. 4 is a cam characteristic curve diagram in which the distance from the center is plotted every 10 ° from 0 ° in FIG. 3 in the clockwise direction.

  In FIG. 4, the shape of the cam member 8 according to the present invention is such that the distance from the rotation center of the cam member 8 to the cam surface (referred to as the head length) suddenly rises from 0 ° to 90 °, and from 90 ° to 270 °. It can be seen that is gradually increasing. In other words, the shape of the cam member 8 is such that when the rotational speed of the cam member 8 is constant, the pressure member 3 is pressed against the member to be pressed 2 and the pressure unit 10 is moved in the direction of the member to be pressed 2. The speed is set to be slower than the speed at which the pressurizing unit 10 is moved until the pressurizing member 3 is crimped to the pressed member 2. The moving speed is related to the rotating torque for rotating the cam member 8, and the rotating torque can be kept lower as the moving speed is slower.

  The cam member 8 used in the present embodiment has a cam shape in which the lift length at 0 ° in FIG. 4 is 3 mm, the lift length is 6 mm at 90 °, and the lift length is 6.6 mm at 270 °. . That is, when the cam member 8 is rotated by 90 °, the pressure unit 10 is lifted by 3 mm, and the pressure member 3 is pressure-bonded to the member 2 to be pressed. However, when the cam member 8 is in the range of 90 ° to 270 °, the pressure unit 10 rises only 0.6 mm.

  At this time, the rotational torque of the cam member 8 (see the vertical scale on the right side in FIG. 4) is applied to the pressure unit 10 until the pressure member 3 comes into contact with the member to be pressurized 2 (90 ° position in FIG. 4). Since the speed when moving in the direction of the pressure member 2 is high, the rotational torque is 3 N · cm. However, since the speed when moving the pressure unit 10 from 90 ° to 270 ° in the direction of the member to be pressed 2 is slow, the rotational torque required to rotate it was 3.3 N · cm. That is, the rotational torque fluctuation range is 0.3 N · cm, and it can be said that the load fluctuation is small. The cam member 8 rotates 270 °, and then reversely rotates (clockwise) and waits at an initial position.

  As shown in FIG. 1, when the pressing member 3 and the pressed member 2 are separated from each other, the cam member 8 is in contact with the contact roller 9 at a position of 0 °. At this time, the urging means 6 is in a state where it cannot be further extended by the urging means restricting portion 51.

  5 shows that when the cam member 8 rotates counterclockwise and reaches a position near 90 ° in the cam characteristic curve diagram of FIG. 4, the pressure member 3 rises and contacts the member to be pressed 2. It is a figure which shows the place which tries to.

  When the pressure member 3 is in contact with the member 2 to be pressed and the cam member 8 is further rotated counterclockwise (position from 90 ° to 180 ° in the cam characteristic curve diagram), the member 3 is pressed. When the member 2 comes into contact with the member 2 and rises further than the range in which the urging means 6 is restricted, the pressure member support member 4 is deviated from the restriction of the urging means restricting part 51 (see FIG. 6a). The pressure-bonding force between the pressure member 3 and the member to be pressed 2 becomes a compression force corresponding to the displacement amount of the biasing means 6.

  When the cam member 8 further rotates counterclockwise and reaches a state of 270 ° in the cam diagram, the compressive force of the urging means 6 becomes maximum (see FIG. 7).

  In addition, the pressure release cam device of the present invention can be applied to a fixing device of an image forming apparatus using an electrophotographic system. That is, the member to be pressed 2 can be a roller-shaped heating roller. The heating roller is composed of a laminate of a hollow cored bar, an elastic layer such as silicon rubber covering its outer peripheral surface, and a release layer such as a fluororesin covering its outer peripheral surface. A heating source such as a halogen lamp is inserted inside the roller.

  The pressure roller 3 is configured as a soft roller by covering a solid metal core made of metal such as iron with a heat-resistant silicone sponge, and presses the heating roller.

  FIG. 9 is a diagram illustrating an image forming apparatus. In FIG. 9, the image forming apparatus A includes an automatic document feeder ADF, an apparatus main body A1, and the like. The apparatus main body A1 includes an image reading device 101, a control unit 201, an image writing device 301, an image forming unit 401, a paper feed tray 501, a transport unit 601, a fixing device 701, a paper discharge unit 801, a re-transport unit 81A, and the like. ing.

  The optical system of the image reading apparatus 101 includes an exposure unit 141 including a light source and a first mirror, a V mirror unit 151 including a second mirror and a third mirror, a lens 161, and a CCD image sensor 171.

  Reading of a document by the automatic document feeder ADF is performed at a position where the exposure unit 141 stops at an initial position below the slit exposure glass 131.

  Reading a document on the platen glass 111 is performed while moving the exposure unit 141 and the V mirror unit 151.

  Image information of the original image read by the image reading apparatus 101 is subjected to image processing by the control unit 201, converted into a signal as image data, and temporarily stored in a memory. Output light from a semiconductor laser (not shown) included in the image writing unit 301 is applied to the photosensitive drum 211 which is a photosensitive member to form an electrostatic latent image.

  In the image forming unit 401, the surface of the photosensitive drum 211 is charged by the charger 221, and an electrostatic latent image is formed by irradiation of laser light from the semiconductor laser of the image writing unit 301.

  Next, the developing device 231 develops the electrostatic latent image with toner to form a toner image. The toner image is transferred onto the paper P conveyed from the paper feed tray 501 by the transfer device 29A. The paper P on which the toner image is transferred is peeled off from the surface of the photosensitive drum 211 by the separator 29B. Thereafter, the transfer residual toner on the photosensitive drum 211 is removed by the cleaning device 261. The sheet P on which the toner image has been transferred is transported by the transport unit 601, fixed by the heating roller 71 and the pressure roller 72 in the fixing device 701, and transported to the paper discharge tray 811 outside the device by the paper discharge unit 801. .

  As described above, the pressure-release releasing cam device of the present invention is provided with a roll-shaped pressing member 3 and a roll-shaped pressed member 2 that is disposed at a position facing the pressing member 3 and is pressed by the pressing member 3. And an urging means 6 for urging the pressing member 3 and an urging means restricting portion 51 for restricting the urging means 6 to a predetermined pressure. Furthermore, it has a pressure unit 10 and a cam member 8 that presses and releases the pressure member 3 and the member 2 to be pressed. Then, until the pressure member 3 is crimped to the member to be pressurized 2 by rotating the cam member 8, the direction of the member to be pressurized 2 is adjusted in a state where the displacement amount of the urging means 6 is regulated. , The cam member 8 is rotated, and the pressure member 3 is pressure-bonded to the member 2 to be pressed. Further, when the pressurizing unit 10 is moved in the direction of the pressed member 2, the restriction of the displacement amount of the biasing means 6 is released, and the pressing member 3 is moved in the direction of the pressed member 2 by the biasing means 6. It is set as the structure which performs the effect | action to energize.

  Further, the cam member 8 has a speed at which the pressure member 3 is pressed against the member to be pressurized 2 when the rotation speed of the cam member 8 is constant, and the pressure unit 10 is moved in the direction of the member to be pressurized 2. However, the pressure member 3 has a cam shape that is slower than the speed at which the pressure unit 10 is moved until the pressure member 3 is pressure-bonded to the member 2 to be pressed.

  If the moving speed is fast, the rotational torque required to rotate the cam member 8 increases, and if it is slow, the rotational torque may be small. At this time, it is desirable that the distance that the pressure unit 10 moves until the pressure member 3 is pressure-bonded to the member 2 to be pressed is much longer than the distance that the pressure unit 10 further moves after the pressure-bonding, and it is desirable to move it quickly. The rotational torque T1 of the cam member 8 necessary to move the pressurizing unit 10 until the pressurizing member 3 is crimped to the pressed member 2 only lifts the mass of the pressurizing unit. The distance by which the pressure unit is further moved after the pressure bonding is a length for releasing the restriction of the displacement amount of the urging means 6, and since the movement amount is small, the rotational torque T2 required at that time is substantially the same as T1. be able to.

  Therefore, when the pressure member 3 and the member to be pressed 2 are pressure-bonded and released using the cam member 8, fluctuations in rotational torque necessary to rotate the cam member 8 are reduced, and the cam member 8 and A crimp release cam device that suppresses partial wear of the mating member can be provided.

It is a side view which shows the crimp release cam apparatus of this invention. It is a disassembled perspective view of the pressure release cam apparatus of this invention. It is an external view of a cam member. It is a cam characteristic curve figure. It is a figure which shows the place where a pressurization member raises and tries to contact a to-be-pressurized member. It is a figure which shows the place where the clearance gap between a pressurization part support member and a biasing means control part generate | occur | produces. It is a figure which shows the place where the biasing means 6 compression force becomes the maximum. It is a figure which shows the pressurization method of the conventional fixing device. 1 is a diagram illustrating an image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crimp release cam apparatus 2 Pressurized member 3 Pressurizing member 4 Pressurizing part support member 5 Supporting part guide member 6 Biasing means 7 Biasing means support member 8 Cam member 9 Contact roller 10 Pressure unit A Image forming apparatus

Claims (5)

A pressurized member;
A pressure member that is disposed at a position facing the member to be pressed and moves in the direction of the member to be pressed; and
Urging means for urging the pressing member in the direction of the pressed member;
An urging means restricting portion for restricting a displacement amount of the urging means;
A pressure unit having at least the pressure member, the urging means, and the urging means regulating portion;
A cam member that moves the pressure unit in the direction of the member to be pressed by rotating, and presses and releases the pressure member and the member to be pressed;
The pressure unit is moved in the direction of the pressed member while the displacement amount of the urging means is regulated until the pressing member is crimped to the pressed member after the cam member is rotated. Let
When the cam member is rotated so that the pressure member is crimped to the member to be pressurized, and the pressure unit is moved in the direction of the member to be pressurized, the displacement amount of the urging means is restricted. The action of releasing and urging the pressing member in the direction of the member to be pressed by the urging means,
When the rotational speed of the cam member is constant, the cam member has a pressure when the pressure member is pressed against the member to be pressurized and the pressure unit is moved in the direction of the member to be pressurized. A pressure-release releasing cam device having a cam shape that is slower than a speed at which the pressure unit is moved until the pressure member is pressure-bonded to the member to be pressed. 2. The pressure-release releasing cam device according to claim 1, wherein a contact roller that rotates in contact with the cam member is provided in the pressure unit. When releasing the pressure bonding between the pressure member and the member to be pressurized, the pressure unit is rotated in a direction opposite to the rotation direction of the cam member when moving the pressure unit in the direction of the member to be pressurized. The pressure-release releasing cam device according to claim 1 or 2 . The pressure unit is
A pressure member supporting member that supports the pressure member and is inserted between the urging unit regulating unit and the urging unit;
A support part guide member for guiding the pressure part support member to move in the direction of the member to be pressed;
An urging means supporting member that supports at least the urging means and the support portion guide member;
Have
The pressure-release releasing cam device according to any one of claims 1 to 3, wherein the pressure member and the member to be pressed have a roll shape. According pinch release cam device according to any one of claims 1 to 4 is a fixing device, an image forming apparatus characterized by using the pinch release cam device.

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