JP6463099B2 - Fixing device - Google Patents

Description

  The present invention relates to a fixing device mounted on a toner image forming apparatus such as an electrophotographic copying machine.

  A fixing device mounted on a toner image forming apparatus generally fixes a toner image to a recording material while nipping and conveying the recording material on which the toner image is formed between two rotating bodies (nip portion). . In order to perform a good fixing process, the pressure applied to the nip portion must be appropriate. For example, the pressure may not be as designed. In general, springs for applying pressure to the nip portion are provided independently at both ends of the nip portion, and it is difficult in terms of mechanical accuracy to make the pressure balance at both ends completely the same. When the balance of the load applied to the nip portion is lost, the image quality is deteriorated and the recording material is wrinkled.

  Patent Document 1 describes a fixing device that can finely adjust the pressure applied to the nip portion.

Japanese Patent No. 3885534

  The fixing device described in Patent Document 1 is a lever in which a fastening portion of a rod that fixes a spring so that the amount of compression of the spring does not return to the original after finely adjusting the amount of compression of the spring with a jig, holds the rotating body rotatably. It is provided on the opposite side to the region where the spring is provided with the boundary. Therefore, the rod is very long, and there is room for improvement in consideration of downsizing of the apparatus.

  An object of the present invention is to provide a fixing device that can suppress an increase in the size of the device by downsizing a mechanism that finely adjusts the pressure applied to the nip portion.

The present invention for solving the above-described problems includes a first rotating body, a second rotating body that contacts the first rotating body, and a fixed frame that rotatably holds the second rotating body. A lever member that is pivotable with respect to the fixed frame and biases the first rotating body against the second rotating body; and an elastic member that applies a biasing force to the lever member. A member and a second end of the elastic member opposite to the first end of the lever member are provided so as to be movable in the direction of the biasing force with respect to the fixed frame. The moving member, the restricting member fixed to the fixed frame so as to be movable and determining the position of the moving member, and the lever member acting on the first member by the biasing force of the elastic member. Reduce the pressure applied between the rotating body and the second rotating body. Anda cam member for, in the fixing device for fixing a recording material a toner image while the recording material is pinched and conveyed carrying the toner image between said first rotary member and the second rotary member The regulating member is fixed to the fixed frame on the second end side of the elastic member, and the elastic member, the moving member, the regulating member, and the cam member are arranged substantially in a straight line. It is characterized by being.
The present invention also relates to a first rotating body, a second rotating body that contacts the first rotating body, a fixed frame that rotatably holds the second rotating body, and the fixed frame. A lever member that is provided so as to be rotatable and that biases the first rotating body against the second rotating body, an elastic member that applies a biasing force to the lever member, and the elastic member A movable member provided on the second end side opposite to the first end portion on the lever member side of the movable member so as to be movable in the direction of the biasing force with respect to the fixed frame; And a restricting member fixed to the frame so as to be movable and determining a position of the moving member, and carrying a toner image between the first rotating body and the second rotating body In a fixing device that fixes a toner image to a recording material while nipping and conveying the material, The regulating member is fixed to the fixed frame on the second end side of the elastic member, and the first rotating body, the second rotating body, the elastic member, and the moving member, The restriction member is arranged on a substantially straight line.

  According to the present invention, an increase in the size of the apparatus can be suppressed.

1 is a perspective view of a fixing device according to a first exemplary embodiment. Sectional view of the fixing device of Example 1 FIG. 3 is a perspective view of a roller pair of the fixing device according to the first exemplary embodiment. Sectional drawing for demonstrating a pressure adjustment mechanism Enlarged sectional view of the pressure adjustment mechanism Figure when the pressure adjustment mechanism is viewed from the direction of the arrow in FIG. A figure showing how the spring is compressed with a jig The figure which showed a mode that a regulation member was fastened in the state where a spring was compressed The perspective view of the fixing device of Example 2. FIG. Side view of the fixing device according to the second embodiment. Perspective view showing pressure adjustment mechanism A figure showing how the spring is compressed with a jig The figure which showed a mode that a regulation member was fastened in the state where a spring was compressed Side view of the fixing device according to the third embodiment.

Example 1
The fixing device of this example will be described with reference to FIGS. 1 is a perspective view of the fixing device 72, FIG. 2 is a sectional view of the fixing device, and FIG. 3 is a perspective view of the vicinity of a roller pair. The fixing device 72 includes a fixed frame 91, a heating unit 82, a pressure roller (second rotating body) 83, and the like. The heating unit 82 includes a cylindrical film (first rotating body) 89 having a base layer made of a metal such as stainless steel or a resin such as polyimide. A ceramic heater 85 is in contact with the inner surface of the film 89, a heater support member 86 made of heat-resistant resin, and a stay that reinforces the heating unit made of 88-wave metal. The pressure roller 83 is in contact with the film 89. The roller 83 is an elastic roller in which a silicone rubber layer is provided around the core metal, and is rotatably held by the fixed frame 91. When a driving force is applied to the roller 83 from a motor (not shown), the film 89 is driven to rotate. A lever member 84 is provided so as to be rotatable with respect to the fixed frame 91 and biases the film 89 against the roller 83. A compression spring (elastic member) 87 applies an urging force to the lever member 84. The heating unit 82 is urged toward the pressure roller 83 by the urging force of the compression spring 87 via the lever member 84, a flange 90, which will be described later, and the stay 88, and this force causes the nip between the film 89 and the roller 83. The part is formed. An arrow Ft indicates a pressing position of the flange member 90 by the lever member 84. Reference numeral 90 denotes a flange member for restricting the movement of the film 89 in the direction of the generatrix. The toner image is fixed to the recording material while the recording material carrying the toner image is nipped and conveyed between the film 89 and the roller 83 in the direction of arrow P. A cam member 95 reduces the pressure applied between the film 89 and the roller 83 by the biasing force of the spring 87 by acting on the lever member 84. Release (reduction) of the pressure contact of the nip portion is performed by rotating the lever member 84 by the cam member 95.

  Next, a configuration in which the heating unit 82 and the pressure roller 83 are pressed against each other will be described with reference to FIG.

  The heating unit 82 and the pressure roller 83 are held by frames 91 provided at both ends in the axial direction (longitudinal direction) of the roller 83. A guide portion 91 a that guides the heating unit 82 and the pressure roller 83 in the direction Fp for pressing is provided on the frame 91, and the pressure roller 83 is rotatably fixed to the frame 91. The heating unit 82 is brought into pressure contact with the pressure roller 83, and the lever member 84 that rotates about the rotation fulcrum 91 b provided on the frame 91 is pressed by the spring 87 in the arrow direction Ft. The spring 87 has a fixed end (first end) 87 a fixed to one end of the lever member 84 and a second end 87 b which is the other end.

  93 is provided on the side of the second end 87 b opposite to the first end 87 a on the lever member 84 side of the spring 87 so as to be movable in the direction of the urging force Fs with respect to the fixed frame 91. It is an elastic member support (moving member). In this example, the support base 93 is fixed to the second end portion 87 b of the spring 87. The support base 93 is a place pressed by a jig T described later when the compression amount of the spring 87 is finely adjusted. Reference numeral 94 denotes a restricting member (rod) fixed to the fixed frame 91 so as to be movable, and for determining the position of the support base 93. There is a threaded portion at the tip of the restricting member 94, and it is fastened to a female threaded portion provided in the bent portion 91 d of the fixed frame 91. Thus, the restricting member 94 is fixed to the fixed frame 91 on the second end 87b side of the spring 87. Thereby, the restricting member 94 can be reduced in size, and the apparatus can be reduced in size. Further, since the spring 87, the moving member 93, the restricting member 94, and the cam member 95 are arranged in a substantially straight line, the apparatus can be reduced in size.

  After the position of the support base 93 is adjusted so that the pressure applied by the spring 87 becomes a predetermined pressure, the position of the support base 93 with respect to the frame 91 is determined by fastening the regulating member 94 to the frame 91. That is, the compression amount of the spring 87 is determined. The hardness of the pressure roller 83 and the dimension from the ceramic heater 85 of the heating unit 82 to the fixed end 84a of the lever member 84 vary due to tolerances. Due to these variations, the position of the fixed end 84a where the lever member 84 and the spring 87 abut varies with respect to the frame 91 for each fixing device. For this reason, the adjustment of the pressing force needs to be measured in a state including the above-described variation, and the portion where the pressing force is adjusted is desirably performed on the fixed end 87 b side of the spring 87.

  Next, a method for adjusting the applied pressure of the spring 87 to a predetermined pressure will be described with reference to FIGS. FIG. 5 shows a state before adjusting the pressing force of the spring 87. The spring 87 and the support base 93 are installed on the bent portion 91 c and the bent portion 91 d of the frame 91. First, the support base 93 is pressurized with the jig T. FIG. 6 shows a diagram viewed from the direction of the arrow in FIG. The support base 93 protrudes from the frame 91c by a width D, and the jig T pushes the protruding portion. FIG. 7 is a diagram illustrating a state in which pressure is applied by the jig T. FIG. The support base 93 is pressurized until a desired pressure is obtained with the jig T. Thereafter, the restricting member 94 is tightened toward the support base 93 as shown in FIG. When tightening is completed, the tightening operation is stopped at a position where the pressing force changes while measuring the pressing force.

  The support base 93 for adjusting the pressurizing force with the jig T and the regulating member 94 for holding the pressurizing force can be operated from the same direction. For example, the cam member 95 is arranged on the opposite side of the support base 93 as in this embodiment. This can suppress the increase in size of the apparatus. Further, the support base 93 can be held by the regulating member 94 while measuring the applied pressure, and there is no need to retract the jig T and hold the support base 93. Moreover, since it is the structure which hold | maintains only by making the support member 93 contact the control member 94, since it is a structure which cannot apply external force to the support stand 93, the fluctuation | variation of the pressurization accompanying adjustment can be suppressed.

(Example 2)
A fixing device according to the second exemplary embodiment will be described with reference to FIGS. Note that description of parts common to the first embodiment is omitted. The difference from the first embodiment is the structure of the support base (moving member) and the regulating member. A configuration for press-contacting the heating unit 82 and the press-contact roller 83 will be described with reference to FIGS. 9 and 10. FIG. 9 is a perspective view of the fixing device, and FIG. 10 is a side view.

  The compression spring (elastic member) 87 has a fixed end 87 a fixed to one end of the lever member 84, and a fixed end 87 b fixed to the support base 103 arranged to be movable in the pressurizing direction Fs. The support base 103 moves by adjusting with a jig (not shown) so that the pressure of the spring 87 becomes a predetermined pressure, and is finally restricted with respect to the frame 91 by the restriction member 104. The spring 87, the support base 103, and the restriction member 104 are housed using the frame auxiliary member 102 after being incorporated in the frame 91.

  Next, a method for adjusting the pressing force of the spring 87 to a predetermined pressure will be described with reference to FIGS. FIG. 11 is a perspective view showing configurations of the support base 103 and the regulating member 104. The support base 103 has a shaft 103 a that protrudes through the restriction member 104. The regulating member 104 is provided with an opening 104b having a long hole, and can be moved in the arrow direction Fa by a tightening member 104b which is, for example, a screw.

  A method for adjusting the pressure of the spring 87 to a predetermined pressure will be described with reference to FIGS. 12 and 13. The support base 103 is provided with a wedge shape that is paired with the regulating member 104. As shown in FIG. 12, the support base 103 moves in the arrow direction Fs when the jig T pressurizes the shaft 103a. The jig T stops in a state where the pressure measured by the jig T reaches a predetermined applied pressure. Thereafter, as shown in FIG. 13, for example, by tightening a tightening member 104 b that is a screw, the regulating member 104 is moved in the arrow direction Fa, and the support base 103 is held by the frame 91. When tightening is completed, the tightening operation is stopped at a position where the pressing force changes while measuring the pressing force.

  In this example, in addition to the effect of the first embodiment, it is possible to hold the support base 103 in a wide area, and it is possible to reduce a change in the applied pressure due to the posture of the support base 103 being lost due to vibration. Further, by dividing the frame that regulates the pressing direction like the frame auxiliary member 102, it is possible to mount components from the pressing direction and improve workability.

(Example 3)
The fixing device of Example 3 will be described with reference to FIG. In this example, the film 89, the roller 83, the spring 87, the moving member 93, and the regulating member 94 are arranged on a substantially straight line.

  The heating unit 82 and the pressure roller 83 are held by frames 111 provided at both longitudinal ends. A guide portion 111 a that guides the heating unit 82 and the pressure contact roller 83 in the direction Fp to be pressed is provided on the frame 111, and the pressure contact roller 83 is fixed to the frame 111. The heating unit 82 is brought into pressure contact with the pressure roller 83, and the lever member 114 that rotates about the rotation fulcrum 111 b provided on the frame 111 is pressed in the arrow direction Ft by the compression spring 87. The spring 87 has a fixed end 87a fixed to one end of the lever member 114, and a fixed end 87b fixed to a support base 93 arranged to be movable in the pressurizing direction Fs. The heating unit 82 and the pressure roller 83 are disposed immediately above. By disposing the spring 87 immediately above the heating unit 82 and the pressure roller 83, the force for pressing the heating unit 82 and the pressure roller 83 can be directly measured. Thereby, it is not necessary to consider the dimensional variation of the lever member 114, and the pressure can be adjusted with high accuracy.

72 Fixing Device 82 Heating Unit 83 Pressing Roller 84 Lever Member 87 Spring 91 Frame 93 Support Base 94 Regulating Member

Claims (2)

A first rotator, a second rotator that contacts the first rotator, a fixed frame that rotatably holds the second rotator, and a mechanism that is rotatable with respect to the fixed frame. A lever member for biasing the first rotating body against the second rotating body, an elastic member for applying a biasing force to the lever member, and the lever member side of the elastic member A moving member provided on the second end side opposite to the first end of the first frame so as to be movable in the direction of the biasing force with respect to the fixed frame, and movable with respect to the fixed frame And a restricting member for determining the position of the moving member, and acting on the lever member, so that the biasing force of the elastic member causes the first rotating body and the second rotating body to be interposed between the first rotating body and the second rotating body. a consuming a cam member for reducing the pressure, the said The fixing device for fixing a recording material a toner image while the recording material bearing the toner image is nipped and conveyed between said one of the rotational body second rotating body,
The restricting member is fixed to the fixed frame on the second end side of the elastic member ;
The fixing device, wherein the elastic member, the moving member, the restricting member, and the cam member are arranged in a substantially straight line . A first rotator, a second rotator that contacts the first rotator, a fixed frame that rotatably holds the second rotator, and a mechanism that is rotatable with respect to the fixed frame. A lever member for biasing the first rotating body against the second rotating body, an elastic member for applying a biasing force to the lever member, and the lever member side of the elastic member A moving member provided on the second end side opposite to the first end of the first frame so as to be movable in the direction of the biasing force with respect to the fixed frame, and movable with respect to the fixed frame And a restricting member for determining the position of the moving member, and sandwiching and conveying a recording material carrying a toner image between the first rotating body and the second rotating body. In a fixing device for fixing a toner image to a recording material,
The restricting member is fixed to the fixed frame on the second end side of the elastic member;
The first rotating member and the second rotating member and the fixed Chakusochi elastic member and the movable member and the regulating member you characterized in that it is disposed substantially on a straight line.

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