JP2007212555A - Fixing device of image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device having a belt body, the fixing device is designed so as to prevent damage to the edge faces of the belt by achieving control of belt skew without involving an increase in the heat capacity, size, or cost of the device. <P>SOLUTION: The position of the fixing belt is detected, and the angle of each of running ribs disposed in contact with the internal face of the belt is altered, based upon the result of the detection. The alteration of the angle makes it possible for each rib to apply running force (resistance) opposite to the direction of skew to the internal face of the fixing belt, thereby returning the fixing belt to its normal direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer capable of forming an image on a sheet material by an image forming unit, such as an electrophotographic system or an inkjet system.

  In general, in an image information recording apparatus such as a copying machine adopting an electrophotographic system, a heating / pressure type fixing device is usually provided in order to fix a toner image transferred onto a recording sheet. Conventionally, this type of fixing device includes a fixing member provided with surfaces that rotate while being pressed against each other, and a pressure member, and a transfer material on which an unfixed toner image is formed is placed between the fixing / pressure members. There has been known a fixing device that is inserted into the printer and fixed an unfixed toner image.

  Here, in recent years, energy saving of image forming apparatuses has been accelerated rapidly. Among them, the above-described heating-type fixing device is generally the device that consumes the most energy among the image forming apparatuses, and thus various methods are used to save energy.

  Among these methods, there is a method for reducing the start-up time by reducing the heat capacity of the fixing / pressurizing member as the most effective method for energy saving. As a specific apparatus, a fixing apparatus using a belt / film as either a fixing member or a pressure member is known.

  According to this method, the start-up time of the fixing device is shortened and there is an energy saving effect. However, since the belt / film is used, it is necessary to regulate and control the belt / film shift.

For example, Patent Document 1, Patent Document 2, and Patent Document 3 can be cited as conventional examples.
JP 2000-72271 A JP-A-11-249464 Japanese Utility Model Publication No. 5-14046

  In general, when the device is low-speed (the number of output sheets is small), the belt / film end faces the belt / film end face by using a flange that regulates the deviation, even if the belt / film approaches one side, and hits the flange face. Was prevented from breaking without full belt / film life.

  Next, when the device is high-speed (the number of output sheets is large), the belt / film side also naturally increases the side-by-side shift speed, so the impact force that collides with the abutting flange surface increases, and the belt / film Damage to the end face and the abutting flange surface will increase.

  In parallel with energy saving, colorization is also accelerating.

  Here, in order to obtain an image with good color, an elastic layer is provided on the belt / film surface. Providing an elastic layer requires pressure to crush the elastic layer to some extent.

  The belt / film misalignment is generated by the alignment misalignment of the unit in which the larger pressing force is small. As the pressure increases further, the shifting force increases.

  As the shifting force increases, the force with which the belt / film end surface collides with the abutting flange surface increases as in the case of the above-described speeding up, and the damage applied to the belt / film end surface and further to the abutting flange surface. Will become bigger.

  Furthermore, there is a need for both colorization and high speed. Conventionally, in order to obtain a color image in general, it is necessary to fix more toner than monochrome.

  The above indicates that more heat must be applied to the transfer material than monochrome. In addition, since it is necessary to increase the speed, the width for applying heat, that is, the nip width must be increased. This requires a further increase in pressure and leads to an increase in belt shifting force.

  As a means to avoid the damage of the belt / film end face and the abutting flange face due to the increase in the belt shifting speed and shifting force accompanying the increase in the speed / coloring, the belt / film has a belt / A method of abutting a steering shaft that controls the shift of the film is often used.

  This is because the belt / film in the direction opposite to the direction of approaching the belt / film by changing the angle of the steering shaft that contacts the belt / film when the belt / film is on one side of the belt / film inner circumference. This is a system that prevents the belt / film from slipping by giving running force.

  However, the above-described method of providing the steering shaft, that is, the method of three shafts for passing the belt, has the following problems in order to save energy of the fixing device, that is, to reduce the heat capacity and size of the fixing device.

-Increased heat capacity for the steering shaft-Increased belt / film diameter and equipment size by inserting the steering shaft (cost increase for steering shaft + steering shaft support)
As a method of avoiding the above-mentioned problem due to the method of providing the steering shaft / the method of using the three-axis system, it is simply necessary to use two shafts for the belt.

  Hereinafter, a fixing device devised to avoid the above-described problems and achieve downsizing / low heat capacity / high speed / colorization of the fixing device will be described with reference to FIG.

  In FIG. 8, the transfer material P is introduced into the fixing device 3 through the conveyance path 61 and the fixing entrance guide 68 in the direction of arrow H.

  The transfer material P introduced into the fixing device 3 is heated / pressurized by the fixing member 1 and the pressure member 2, whereby the toner image is fixed to the transfer material P.

  The transfer material that has been heated / pressurized and to which the toner image has been fixed is regulated in position by an upper outlet guide 97 and a lower outlet guide 98, guided to the upper outlet roller 45 and the lower outlet roller 46, and is sent to a post-conveyance not shown. And finally discharged out of the image forming apparatus.

  Hereinafter, the configuration of the fixing device 3 will be described in detail.

  FIG. 9 is an enlarged view showing a surface layer A portion of the fixing belt 4 and the pressure belt 7.

  As shown in FIG. 9, the fixing member 1 is a member in which a metal is used for the tubular base material 52, Si rubber is provided on the outer surface 53 of the base material 52, and a fluorine layer is provided on the outermost layer 54. Hereinafter, the above-described fixing member is referred to as a fixing belt 4.

  The fixing belt 4 has a rotation drive shaft 5 that includes a heat source that heats the fixing belt by applying driving for rotating the fixing belt 4 to the inner periphery thereof, and fixing that stabilizes the shape of the fixing belt 4 and the running of the fixing belt 4. It is wound around by the belt guide 6.

  Next, as with the fixing member 1 shown in FIG. 9, the pressurizing member 2 uses a metal for the tubular base material 55, Si rubber is provided on the outer surface 56 of the base material 55, and a fluorine layer is provided on the outermost layer 57. It is. Hereinafter, the above-described pressure member is referred to as a pressure belt 6.

  The pressure belt 7 is stretched around a rotation shaft 8 of the pressure belt 7 and a pressure belt guide 9 that stabilizes the shape of the pressure belt 7 and the travel of the pressure belt 7.

  The fixing belt 4 and the pressure belt 7 are pressurized at a desired pressure, and a nip N is formed at a portion where they are in contact with each other.

  The rotational drive shaft 5 rotates by receiving a driving force from a driving unit (not shown), and the fixing belt 4 rotates by receiving this rotational force.

  The pressure belt 7 pressed against the fixing belt 4 is driven to rotate by the rotation of the fixing belt 4. The transfer P is guided to the rotating fixing belt 4 and the pressure belt 7, and the transfer material P is conveyed.

  Further, the toner image on the transfer material P is heated / pressurized and fixed to the transfer material P by the nip N formed by the pressure contact between the fixing belt 4 and the pressure belt.

  In summary, the fixing device described above takes the following countermeasures against the problem.

● Downsizing → Reduced by the radius of the driven shaft by using a guide instead of the normal driven shaft. By using a belt and film with a high degree of freedom in the shape of the fixing / pressurizing member, the size is reduced by effectively utilizing a finite space. ● Lower heat capacity → Lower heat capacity by using fixing / pressurizing members as belts and films Normally using a driven shaft, but using a guide, the diameter of the belt and film is reduced by reducing the size by the radius of the driven shaft. Higher heat capacity ● Higher speed / colorization → Fixing / Pressure members can use a belt and film with a high degree of freedom in shape to increase the nip width.

  Here, the above-mentioned fixing device can clear downsizing, low heat capacity, high speed, and color, and can expect significant energy saving and high speed color, but there is no means to prevent / control belt and film shift. It was.

  The present invention has been made to solve the above-described problems, and has as its object to propose a fixing device that focuses on energy saving of the fixing device and can increase the speed / color.

  A fixing device having a fixing member for fixing a recording sheet having an unfixed image, and a pressure member for contacting the fixing member to form a nip, wherein the fixing member is an endless belt and a film, and the fixing device Has at least one rotating shaft and a guide that protects the shape and running of the endless belt and film, and the guide protrudes at a distance from the surface of the guide and contacts the inner surface of the endless belt and film. And the endless belt and the film are supported between the at least one rotating shaft and the guide so as to be able to rotate by being suspended between suspension members, and detecting the position of the endless belt. And a fixing device having a control means for driving / controlling an actuator using a signal from the detection device. Te is capable of changing its angle to the running direction of the endless belt and the film of the rib.

  By configuring the rib contacting the belt as described above so that the angle can be changed, it is possible to control the belt shift in a downsized / low heat capacity / high speed / colorized fixing device, and downsize / low heat capacity. It is possible to provide a high-speed / colorized image forming apparatus.

  Hereinafter, an embodiment of a fixing device of an image processing apparatus to which the present invention is applied will be specifically described with reference to the drawings.

  Note that members having the same functions as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 1 is a sectional view of a fixing device according to the present invention.

  Ribs 10 are disposed on the guide surface S of the fixing belt guide 6 and the pressure belt guide 9 in FIG. 1 on the side in contact with the belt to reduce the contact area between the belt and the guide and reduce the sliding resistance.

  Here, the rib 10 disposed on the guide surface S of the fixing belt guide 6 will be described with reference to FIG.

  FIG. 2 is a view of the fixing belt guide 6 seen from the direction of arrow A in FIG.

  The guide surface S of the fixing belt guide 6 is provided with a relief hole 11 for allowing the rib 10 to protrude from the guide surface S by a certain amount and to contact the fixing belt 4.

  The rib 10 is normally disposed horizontally with respect to the conveyance direction of the fixing belt 4. The sensor detects that the fixing belt 4 has moved to either side, and changes the angle of the rib 10 to generate a force in the direction opposite to the direction toward the inner peripheral surface of the fixing belt 4. Control is performed to keep the range within the range where damage does not occur.

  The belt deviation control and the angle changing mechanism of the rib 10 will be described in detail below with reference to FIGS.

  The angle changing mechanism of the rib 10 is configured as follows.

  The rib 10a and the rib 10b have the same shape. As a representative example, the shape of the rib 10a will be described.

  The rib rotation shaft 12a is disposed at one end of the rib 10a. The rib rotation shaft 12a is engaged with a rib rotation shaft hole 18a disposed in the base 17, and the rib 10a is configured to be capable of changing the angle around the rib rotation shaft 12a.

  Next, a guide pin groove 13a having a certain groove length is disposed at the end opposite to the rib rotation shaft 12a disposed at one end of the rib 10a.

  Next, the joint rod 14 connected to the ribs 10a and 10b will be described.

  Guide pins 15 a and 15 b are arranged on the joint rod 14. The guide pins 15a and 15b engage with the guide pin grooves 13a and 13b of the ribs 10a and 10b.

  The joint rod 14 is further provided with a spring seat 72 for receiving a spring 19 for urging in the direction of arrow B. Correspondingly, the base 17 is provided with a spring seat 20 for receiving the spring 19.

  Further, the joint rod 14 is provided with a bearing portion 75 for smooth movement in the thrust direction. Correspondingly, a bearing 73 is arranged on the base 17.

  An angle changing finger 21 is provided at the end of the joint rod 14.

  The angle changing finger 21 comes into contact with the cam surface of the cam 24 installed on the side plate 22 of the fixing device 3.

  The cam 24 is rotatably arranged on the side plate 22 and is driven to rotate by an actuator (such as a motor) not shown.

  On the side plates 22 and 23, belt deviation detection sensors 25 and 26 for detecting the position of the belt end of the fixing belt 4 are arranged.

  The configuration of the mechanism portion of the belt deviation control mechanism using the rib 10 in the present invention is as described above.

  Next, shift control using the above-described mechanism will be described with reference to FIGS.

  First, it is assumed that the fixing belt 4 has moved in the direction of the arrow C.

  1. The belt deviation detection sensor 25 detects (ON) the belt deviation.

  2. The actuator is operated so that the cam 24 rotates in the arrow D direction.

  3. When the cam 24 rotates in the direction of the arrow D, the joint rod 14 moves in the direction of the arrow E through the angle changing finger 21 of the joint rod 14 that is in contact with the cam 24.

  4). As the joint rod 14 moves, the guide pin 15 also moves in the direction of arrow E. By the guide pin groove 13 fitted to the guide pin 15, the rib 10 moves to a predetermined angle around the rib rotation shaft 12 as the joint rod 14 moves.

  By performing the above operation, the angle of the rib 10 is changed. By changing the angle, the rib 10 can apply the running force (resistance) of the fixing belt 4 opposite to the direction toward the inner surface of the fixing belt 4, and the fixing belt 4 moves in the direction of the arrow F to be normal. Return to position.

  When the fixing belt 4 approaches the belt deviation detection sensor 26 side, the same operation can be performed by returning the fixing belt 4 to the normal position by performing the control of rotating the cam 24 in the reverse direction.

  So far, the mechanism / configuration / control of the present invention has been described using the fixing belt 4. The same applies to the pressure belt 7 in the configuration of this embodiment. The pressure belt 7 side will not be described because the same effect can be obtained with the same mechanism / configuration / control.

  By adopting the above-described configuration, it is possible to control the belt shift in a downsized / low heat capacity / high speed / colorized fixing device, and downsized / low heat capacity / high speed / colorized image formation. An apparatus can be provided.

  A second embodiment of the present invention will be described with reference to FIG.

  The configuration and control for changing the angle of the rib 10 are the same as in the first embodiment.

  In the first embodiment, the fixing belt 4 is stretched between the rotation drive shaft 5 and the fixing belt guide 6, and the pressure belt 7 is stretched between the rotation shaft 8 and the pressure belt guide 8. 4 and the pressure belt 7 were brought into pressure contact with each other to form a nip.

  In the case of (Example 1), the base material 52/55 of the fixing belt 4 and the pressure belt 7 is made of metal.

  The fixing belt 4 and the pressure belt 7 are used in a state where they are deformed into a desired shape by applying a tension in the direction of the arrow G and mounted on the fixing device 3.

  Here, when the base materials 52 and 55 have a certain thickness, the tension in the arrow G direction increases in order to deform the fixing belt 4 and the pressure belt 7 into desired shapes.

  The increased tension in the direction of arrow G acts as a reaction and acts on the fixing belt guide 6 and the pressure belt guide 8.

  As a result, the contact pressure between the fixing belt 4 and the fixing belt guide 6 and between the pressure belt 6 and the pressure belt guide 8 increases, the sliding resistance increases, and the device driving torque increases.

  This means that although the fixing device itself has been subjected to thermal energy saving, a large amount of electric power is used for rotation.

  Further, in the pressure belt 7 in the case where there is no driving force in particular, the internal sliding resistance increases, and the sliding resistance becomes larger than the frictional force between the pressure belt 7 and the transfer material P. The pressure belt 7 slips and disturbs the image, or the transfer material P cannot be conveyed.

  The countermeasure against slip of the pressure belt 7 can be avoided if the pressure belt 7 is also driven. In addition, it is possible to provide rotating rollers on the surfaces of the fixing belt guide 6 and the pressure belt guide 8 or to attach a sheet that lowers the sliding resistance. However, both increase the cost.

  Therefore, in this embodiment, in order to avoid the sliding resistance problem of the fixing belt guide 6 and the pressure belt guide 8, the fixing belt guide 6 and the pressure belt guide 8 are replaced with rotatable rotary shafts 33 and 34, respectively.

  Further, guides 35/36 for maintaining the shape of the fixing belt 4 and the pressure belt 7 and protecting the running are disposed at positions facing the nip N formed by the fixing belt 4 and the pressure belt 7, respectively.

  The guide 35/36 is provided with the same angle-changeable rib 10 as in (Example 1), and controls each belt shift as in (Example 1).

  In the configuration of this embodiment, the fixing belt guide 6 and the pressure belt guide 8 can be rotated or replaced with a rotation shaft 33/34.

  This is a reversal to miniaturization / reduction in heat capacity, but it is only necessary to achieve a total energy saving by balancing which one should use a large amount of power to rotate as described above.

  By adopting the above-described configuration, it is possible to control the belt shift in the downsized / low heat capacity / high speed / colorized fixing device, and the size can be reduced even when the rotational load of the fixing belt / pressure belt increases. It is possible to provide an image forming apparatus that is reduced, reduced in heat capacity, increased in speed, and colored.

  In the above-described embodiment, the position changing means by the cam is exemplified as the angle changing means of the rib 10. However, the present invention is not limited thereto, and for example, a pinion / rack system may be used, and the rib can be changed in angle. The same effect can be obtained as long as it can be configured.

  In the embodiment described above, the belt deviation detection sensors are arranged at both ends of the belt. However, the present invention is not limited to this, and if the deviation direction is known, only one side may be used to detect the belt deviation. If it is a means, the same effect can be acquired.

  In the above-described embodiment, the case where the number of the angle variable ribs is two is exemplified, but the present invention is not limited to this, and is at least one, and the number varies depending on the request. Any number can be used as long as the same effect can be obtained.

  In the above-described embodiment, the case where the number of the angle variable ribs is two and both are changed to the same angle is exemplified. However, the present invention is not limited to this, and the angles of the plurality of ribs are different from each other. It may be an angle. For example, in this embodiment, by changing the angle of only the rib 10a, the friction force of the rib 10a and rib 10b against the belt is increased on the rib 10a side in the belt thrust direction, thereby moving the belt to a desired position. The same effect can be obtained.

  In the embodiment described above, the metal is exemplified as the base material of the fixing belt / pressure belt, but the present invention is not limited to this, and the same effect can be obtained even if the base material is resinized. .

  In the above-described embodiment, the rotation driving shaft of the fixing belt / pressure belt is positioned on the downstream side with respect to the transfer material P on the fixing belt side, but the present invention is not limited to this, and the pressure belt side A rotation drive shaft may be provided, and a rotation drive shaft may be provided on both the fixing belt and the pressure belt.

  In the above-described embodiment, the base material (metal in the examples) is used for the fixing belt / pressure belt. However, the present invention is not limited to this, and there is no base material. The same effect can be obtained by just using this.

  In the above-described embodiments, the use of the pressure belt has been exemplified. However, the present invention is not limited to this, and a roller may be provided only on the pressure belt side. Conversely, only the fixing roller side may be a roller.

  In the above-described embodiment, the system in which the heat source is included in the rotation drive shaft is illustrated, but the present invention is not limited to this, and may be included in the rotation shaft on the pressure belt side. A heat source may be built in each guide. Further, a heat source may be brought into contact with the surface of one or both of the fixing belt / pressure belt from the outside. Further, either or both surfaces of the fixing belt / and the belt may be heated by induction heating. That is, the position and method of the heat source are not limited.

1 is a cross-sectional view illustrating a configuration of a fixing device according to a first embodiment of the present invention. 1 is a top view illustrating a configuration of a fixing device according to a first embodiment of the present invention. (Figure with the fixing belt 4 removed) 1 is a top view illustrating a configuration of a fixing device according to a first embodiment of the present invention. (Figure with the fixing belt 4 and the fixing belt guide 6 removed) 1 is a perspective view illustrating a configuration of a fixing device according to a first embodiment of the present invention. (The figure which removed the fixing belt 4, the fixing belt guide 6, and the side plate 23) FIG. 3 is a top view showing a state in which the fixing belt 4 of the fixing device according to the first embodiment of the present invention approaches one side. FIG. 3 is a top view showing how the angle of the rib 10 of the fixing device according to the first embodiment of the present invention changes. FIG. 6 is a cross-sectional view illustrating a configuration of a fixing device according to a second embodiment of the present invention. It is sectional drawing which shows the conventional fixing device. 3 is a partially enlarged view showing surface layer configurations of a fixing belt 4 and a pressure belt 7. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing member 2 Pressure member 3 Fixing apparatus 4 Fixing belt 5 Rotation drive shaft 6 Fixing belt guide 7 Pressure belt 8 Rotating shaft 9 Pressure belt guide 10, 10a, 10b Rib 11 Nudge hole 12a, 12b Rib rotating shaft 13a, 13b Guide pin groove 14 Joint rod 15a, 15b Guide pin 16 Bearing portion 17 Base 18a, 18b Rib rotation shaft hole 19 Spring 20 Spring seat 21 Angle change finger 22, 23 Side plate 24 Cam 25, 26 Belt shift detection sensor 33, 34 Rotation Shaft 35, 36 Guide 37, 38 Nip guide 45 Outlet upper roller 46 Outlet lower roller 52 Base material 53 Outer surface (Si rubber)
54 Outermost layer (fluorine layer)
55 Base material 56 Outer surface (Si rubber)
57 Outermost layer (fluorine layer)
61 Conveying path 68 Fixing entrance guide 72 Spring seat 73 Bearing 75 Bearing portion 97 Exit upper guide 98 Exit lower guide P Transfer material N Nip S Guide surface

Claims (3)

A fixing device having a fixing member for fixing a recording sheet having an unfixed image, and a pressure member for contacting the fixing member to form a nip;
The fixing member is an endless belt and a film,
The fixing device has at least one rotating shaft and a guide for protecting the shape and running of the endless belt and the film,
The guide protrudes with a certain distance from the surface of the guide, and has a rib that contacts the inner surface of the endless belt and the film,
The endless belt and the film are supported between the at least one rotating shaft and the guide so as to be able to rotate by being suspended between suspension suspension members.
Having detection means capable of detecting the position of the endless belt;
In a fixing device having a control means for driving / controlling an actuator using a signal from the detection device,
A fixing device configured to change an angle of the rib with respect to a traveling direction of the endless belt and the film. A fixing device having a fixing member for fixing a recording sheet having an unfixed image, and a pressure member for contacting the fixing member to form a nip;
The pressure member is an endless belt and a film,
The fixing device has at least one rotating shaft and a guide for protecting the shape and running of the endless belt and the film,
The guide protrudes with a certain distance from the surface of the guide, and has a rib that contacts the inner surface of the endless belt and the film,
The endless belt and the film are supported between the rotating shaft and the guide so as to be able to rotate by being stretched between suspension suspension members.
Having detection means capable of detecting the position of the endless belt;
In a fixing device having a control means for driving / controlling an actuator using a signal from the detection device,
A fixing device configured to change an angle of the rib with respect to a traveling direction of the endless belt and the film. A fixing device having a fixing member for fixing a recording sheet having an unfixed image, and a pressure member for contacting the fixing member to form a nip;
The fixing device according to claim 1, wherein the fixing member and the pressure member are an endless belt and a film.

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