JP2002082566A - Fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust nip pressure between a fixing roller and a sheet type pressuring member in a fixing device provided with the fixing roller and the sheet type pressuring member. SOLUTION: The sheet type pressuring member 13 having leaf spring property is provided in a cantilevered and supported state on an upstream side in a recording paper carrying direction with respect to the fixing roller 12, and is constituted to abut on the roller 12 in an elastically deformed state, then a coil spring 20 to press the back surface of the member 13 and a pressure adjusting mechanism to move the position of the end of the spring 20 up and down are provided under the member 13. The nip pressure is varied by varying the position of the end of the spring 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device and an image forming apparatus applied to an electrophotographic apparatus such as a facsimile machine, a printer, a copying machine or a multifunction machine having the functions thereof.

[0002]

2. Description of the Related Art FIG. 7 is a side view showing the internal structure of a conventional fixing device.
A fixing roller 52 is disposed inside the fixing roller 50 to heat the fixing roller 50.
3 is a temperature detecting means for detecting the temperature of the fixing roller 50;
Reference numeral 4 denotes a fixing roller 5 which fixes the recording paper adhered to the fixing roller 50.
A separation claw for separating the fixing roller 50 from the fixing roller 55, a cleaning pad 55 that contacts the fixing roller 50 to clean the fixing roller 50, a cleaning pad holder 56 that supports the cleaning pad 55, and a rotation of the fixing roller 50 with respect to the cleaning pad 55. Reference numeral 58 denotes an entrance guide plate attached to the recording paper entrance of the fixing device main body, and 59 denotes a paper discharge roller provided on the recording paper exit side of the fixing device.

The recording paper onto which the toner image has been transferred enters the nip portion between the fixing roller 50 and the pressure roller 51 via the entrance guide plate 58. Then, the toner image is fixed on the recording paper by being pressurized / heated in the nip portion, and then discharged to the outside via the discharge roller 59. The toner adhered to the fixing roller 50 when the recording paper passes through the nip is removed by the cleaning pad 55.

[0004] The surface temperature of the fixing roller 50 is detected by a temperature detecting means 53, and based on the detection result of the temperature detecting means 53, heating control by a fixing heater 52 is performed by a control means (not shown).

Heretofore, in the fixing apparatus, an infrared heater or a halogen heater is adopted as a fixing heater, and a fixing roller and a pressure roller are most commonly used. However, since the pressure roller has a structure in which a silicon rubber layer is formed on a cored bar and a release layer such as a tube made of a fluororesin is formed thereon, the heat capacity increases, and even if heating is started, heat is applied. The pressure roller does not easily warm up, which is a cause of defective fixing. There was also a disadvantage that the parts cost was high. Further, a large pressing force is required in order to secure an appropriate nip width at the nip portion between the fixing roller and the pressure roller, and the pressure causes a stress on the recording paper to cause a fixing wrinkle.

Therefore, a fixing device for forming a nip by pressing a sheet-shaped member against the fixing roller instead of the pressing roller, and fixing the unfixed image to the recording paper by passing the recording paper through the nip portion. Are being studied. With such a configuration, the sheet-shaped member easily warms up, it is possible to secure a nip width, and it is possible to increase the thermal efficiency as compared with the conventional machine.

[0007]

When recording paper of different thicknesses is used when the pressure roller is a sheet-shaped member, the nip pressure is adjusted according to the thickness of the recording paper in order to maintain transportability. Is desirably set, but when the positions of the fixing roller and the sheet-shaped pressing member are fixed, only a fixed nip pressure can be obtained. for that reason,
It is desired to make the nip pressure variable with a simple mechanism. Further, since it is necessary to keep the pressing force (hereinafter, referred to as nip pressure) at the nip portion uniform at each contact portion, it is difficult to control the pressing force.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device and an image forming apparatus which can solve such a problem and make it possible to adjust a nip pressure.

[0009]

According to a first aspect of the present invention, there is provided a cylindrical fixing roller having a heating source therein, and a sheet-like pressing member abutting on the fixing roller. A sheet-shaped pressing member that presses the fixing roller by the leaf spring property of the sheet, and pressurizes the recording sheet on which the toner image has been transferred when the recording sheet passes between the fixing roller and the sheet-shaped pressing member. A fixing device for fixing the toner image on the recording paper by heating, wherein the pressure adjusting unit moves the sheet-shaped pressing member and adjusts a pressure applied from the sheet-shaped pressing member to the fixing roller. It is characterized by having been provided. With this configuration, the nip pressure applied to the fixing roller by the sheet-shaped pressing member can be adjusted.

According to a second aspect of the present invention, in the first aspect of the invention, the pressure adjusting means is disposed between the sheet-shaped pressing member and the main body, and the sheet-shaped pressing member is connected to the main body. It is characterized by comprising an urging member for urging toward the fixing roller side, and a drive control means for vertically moving a lower portion of the urging member. With this configuration, since the urging force of the urging member can be adjusted, the pressure applied by the sheet-shaped pressing member to the fixing roller can be adjusted.

According to a third aspect of the present invention, in the invention according to the second aspect, the urging member has one end for urging the back side of the sheet-shaped pressing member and the other end attached to the drive control means. It is a coil spring. With this configuration, since the pressing force of the coil spring can be adjusted, the pressure applied by the sheet-shaped pressing member to the fixing roller can be adjusted.

According to a fourth aspect of the present invention, in the third aspect of the invention, a plurality of the coil springs are arranged, and the drive control means simultaneously changes the positions of the other ends of all the coil springs. I do. With this configuration, the overall pressure applied to the fixing roller by the sheet-shaped pressing member can be adjusted.

According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the drive control means is provided with an adjusting portion for adjusting an initial position of each other end of the coil spring. With such a configuration, it is possible to adjust the pressure of each part applied to the fixing roller by the sheet-shaped pressing member, and it is possible to adjust the balance of the pressure of each part applied to the fixing roller.

The invention according to claim 6 is the invention according to any one of claims 2 to 5, wherein one end of the coil spring is attached to the back side of the sheet-shaped pressing member, and the drive control means includes: The position of the other end of the coil spring is changed so as to release the contact state between the sheet-shaped pressing member and the fixing roller. With this configuration, the sheet-shaped pressing member can be kept in contact with the fixing roller as needed.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the pressure adjusting means includes a supporting portion for rotatably supporting a fixed end of the sheet-shaped pressing member, and the sheet-shaped additional member. And an adjusting unit for moving the free end of the pressure member up and down. With this configuration, it is possible to adjust the pressing force due to the spring property of the sheet-shaped pressing member.

According to an eighth aspect of the present invention, in the invention according to the seventh aspect, the adjusting portion is inserted into an extending portion formed in a part of the support portion and an elongated hole formed in the extending portion. And a screw member for fixing the extending portion to the main body. With this configuration, the pressing force when the fixing roller is attached can be made variable by adjusting the inclination angle of the sheet-shaped pressing member.

According to a ninth aspect of the present invention, in the invention according to the seventh aspect, a roller body in which the adjusting portion is in contact with the support portion and the rotating shaft is eccentric, and the rotating shaft of the roller body is supported. And a bearing portion to be formed. With this configuration, the inclination angle of the sheet-shaped pressing member can be changed by rotating the roller body.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the rotating shaft has a polygonal prism shape, and the bearing portion has a concave portion adapted to the rotating shaft.
With this configuration, a click feeling can be given when the inclination angle of the sheet-shaped pressing member is switched.

According to an eleventh aspect of the present invention, in the invention according to the ninth or tenth aspect, the rotary shaft is provided with a dial member indicating an index of a rotational position corresponding to a vertical position of the sheet-shaped pressing member. It is characterized by the following. With this configuration, the inclination angle of the sheet-shaped pressing member can be determined by looking at the index.

According to a twelfth aspect of the present invention, in the invention according to the eleventh aspect, the index is a thickness of a recording sheet corresponding to a vertical position of the sheet-shaped pressing member. With this configuration, a nip pressure corresponding to the thickness of the recording paper can be easily obtained.

According to a thirteenth aspect of the present invention, there is provided a cylindrical fixing roller having a heating source therein, and a cantilever supported by a base and abutting on the fixing roller, wherein the sheet-shaped pressing member has a plate spring property. A sheet-shaped pressing member that presses the fixing roller, and passes a recording paper, onto which the toner image has been transferred by an electrophotographic process, through a nip formed between the fixing roller and the sheet-shaped pressing member. A fixing device for fixing a toner image to recording paper by applying pressure / heating at the time of moving the fixing roller to adjust the pressure applied from the sheet-shaped pressing member to the fixing roller. An adjusting means is provided. With this configuration, the amount of deflection of the sheet-shaped pressing member can be changed, and the nip pressure can be adjusted.

According to a fourteenth aspect of the present invention, there are provided a plurality of roller members provided with at least one heating source, a fixing belt stretched by these roller members, and circulating and moving by the rotation of the roller members. And a sheet-shaped pressing member that abuts a part of the sheet-shaped pressing member. When a recording sheet on which a toner image is transferred passes through a nip portion formed between the fixing belt and the sheet-shaped pressing member, pressure is applied. / A fixing device for fixing a toner image on recording paper by heating,
Pressure adjusting means is provided for adjusting the pressure applied from the sheet-shaped pressing member to the fixing belt by moving the sheet-shaped pressing member. With this configuration, the nip pressure applied to the fixing belt by the sheet-shaped pressing member can be adjusted.

According to a fifteenth aspect of the present invention, there is provided a cylindrical fixing member made of a flexible member, driving means for circulating the fixing member, a heating source abutting inside the fixing member, and the heating source. And a sheet-shaped pressing member that comes into contact with the fixing member via the fixing member, and when the recording paper on which the toner image has been transferred passes through a nip portion formed between the heating source and the sheet-shaped pressing member. A fixing device for fixing a toner image on recording paper by applying pressure / heating to the recording sheet, wherein the pressure is adjusted by moving the sheet-shaped pressing member to adjust the pressure applied from the sheet-shaped pressing member to the heating source. An adjusting means is provided. With this configuration, the nip pressure applied to the heating source by the sheet-shaped pressing member can be adjusted.

The invention according to claim 16 is the invention according to claims 1 to
In the invention according to the fifteenth aspect, the sheet-shaped pressurizing member is provided so as to be cantilevered with respect to the nip portion on the upstream side in the recording paper conveyance direction. With this configuration, it is possible to impart to the sheet-shaped pressing member such elasticity that the recording paper passes between the fixing roller and the sheet-shaped pressing member.

The invention according to claim 17 is the invention according to claims 1 to 16
A fixing device according to any one of the preceding claims. With this configuration, it is possible to improve the transportability of the recording paper in the image forming apparatus.

[0026]

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

FIG. 1 is a side view showing the internal structure of a facsimile apparatus having a fixing device according to a first embodiment of the present invention, wherein 1 is a main body of the facsimile apparatus, and 2 is detachably mounted on the main body 1. A process cartridge accommodating various process devices for forming an image by an electrophotographic process; 3, a photoconductor provided in the process cartridge 2; and 4, a laser beam scanned on the photoconductor 3 by a laser beam modulated based on image data. An optical writing device 5; a paper feed cassette 5 for storing recording paper; 6 a paper feed roller for feeding recording paper from the paper feed cassette 5; A transfer roller for transferring the toner image formed on the recording paper; a fixing device for fixing the toner image on the recording paper; a paper discharge roller; a contact sensor;
3 shows a document table formed on the upper surface of the document.

The original set on the original placing table 11 is transported by the transport system, passes through the contact sensor 10, and is discharged to the outside. When a document passes through the contact sensor 10, an image of the document is optically read by the contact sensor 10. The image data read by the contact sensor 10 or the image data input from the outside is sent to the optical writing device 4, and the optical writing device 4 uniformly charges the laser beam modulated based on the image data. By irradiating the surface of the photoconductor 3, an electrostatic latent image is formed.
The toner is attached to the electrostatic latent image to form a toner image, and the toner image is transferred to recording paper by the transfer roller 7.
Then, the toner image is fixed on the recording paper by pressing / heating by the fixing device 8, and is discharged to the outside by the discharge roller 9.

FIG. 2 is an explanatory view showing the structure of the fixing device in FIG. 1. FIG. 2 (a) is a side view, FIG. 2 (b) is a front view, 12 is a fixing roller, and 13 is a sheet shape. A pressure member, a heating source provided inside the fixing roller 12;
Reference numeral 15 denotes a guide plate for guiding the recording paper to the fixing device 8;
Indicates a coil spring, and 21 indicates a pressure adjusting mechanism.

A heating source 14 is provided inside the fixing roller 12. As the heating source 14, an infrared heater, a halogen heater, an induction heating type heater, a sheet heater, or the like is used. The sheet-shaped pressing member 13 has a plate spring property and is made of a metal plate having high heat conductivity, for example, a stainless steel or copper plate. In addition, a fluororesin (PFA, PTFE, FEP)
Etc.) to form a coating layer to smooth the surface. Further, the sheet-shaped pressing member 13 may be made of a fluorine-based resin or polyimide.

A portion of the guide plate 15 facing the fixing roller 12 is formed in a concave shape, and one end of the sheet-shaped pressing member 13 has a screw and a double-sided adhesive tape at an edge of the concave portion on the upstream side in the recording paper conveyance direction. Alternatively, it is fixed by an adhesive, and the other end of the sheet-shaped pressing member 13 can move up and down as a free end.

The position of the fixing roller 12 or the sheet pressing member 13 is set so that the sheet pressing member 13 comes into contact with the fixing roller 12 while applying a predetermined pressure. Therefore, the nip pressure which is the pressure applied by the sheet-shaped pressing member 13 to the fixing roller 12 is determined by the leaf spring property of the sheet-shaped pressing member 13.

As shown in FIGS. 2 (a) and 2 (b), a pressure adjusting mechanism 21 is provided at a portion of the main body 1 facing the back surface of the free end of the sheet-shaped pressing member 13. A plurality of coil springs 20 (three in the longitudinal direction, at the center and at the center) are provided between the back surface of the free end of the sheet-shaped pressing member 13 and the pressure adjusting mechanism 21.

The recording paper conveyed from the transfer roller is guided by a guide plate 15 and
The sheet 2 passes through a contact portion between the sheet-shaped pressing member 13 and the nip portion. At this time, when the recording paper is pressed / heated, the toner image on the recording paper is melted and fixed on the recording paper, and is discharged to the outside via the guide plate 15 and the discharge roller.

FIG. 3 is an explanatory view showing a schematic configuration of the pressure adjusting mechanism shown in FIG. 2. Reference numeral 22 denotes a mounting plate to which one end of the coil spring 20 is mounted.
Reference numeral 4 denotes a screw hole formed at one end of the coil spring 20 at a mounting position, and reference numeral 25 denotes a solenoid that moves the mounting plate 22 up and down.

A pedestal 23 is screwed into the screw hole 24.
One end of the coil spring 20 is placed on the pedestal 23. Then, the pedestal 23 is moved up and down by rotating the pedestal 23 using an instrument such as a driver, and the position of one end of the coil spring 20 is changed. 13 can be adjusted.

Further, by driving the solenoid 25 to move the mounting plate 22 up and down, the other end positions of the respective coil springs are simultaneously switched, and the amount of pressure applied to the sheet-shaped pressing member 13 by the coil springs 20 changes. By doing so, the nip pressure can be changed. The drive control of the solenoid 25 is performed by a CPU (not shown).

Since the vertical movement of the mounting plate 22 is set by the amount of movement by the solenoid 25, for example, it is possible to set a nip pressure for plain paper and a nip pressure for thick paper slightly higher than this nip pressure. it can. If the position of the mounting plate 22 can be switched in multiple stages, more detailed adjustment of the nip pressure is possible.

By setting the amount of movement by the solenoid 25 to be large, the sheet-shaped pressing member 13 can be brought into contact with or separated from the fixing roller 12. For example, in a normal state, the sheet-shaped pressing member 13 is brought into contact with the fixing roller 12, and after the image forming operation is completed, the fixing roller 12 is cooled to a predetermined temperature for a predetermined time, or when a jam occurs, a solenoid is used. Drive control can be performed such that the sheet-shaped pressing member 13 is separated by driving the sheet-like pressing member 13.

According to the first embodiment configured as described above, since the pressure can be adjusted by the individual coil springs 20, the left and right balance of the pressure applied from the sheet-shaped pressing member 13 can be adjusted. become. Further, since the sheet-shaped pressing member 13 can be brought into contact with / separated from the sheet-shaped pressing member 13, it is possible to easily process jammed paper. Further, by urging the free end of the sheet-shaped pressing member 13, it is possible to secure a nip width between the fixing roller 12 and the sheet-shaped pressing member 13, and to control the coil spring by controlling the driving of the solenoid 25. The nip pressure can be made variable by simultaneously changing the vertical position of one end of 20.

Although the three coil springs 20 are used in the first embodiment, the number, type and arrangement of the coil springs 20 may be set as appropriate.

FIG. 4 is a side view showing a main part of a fixing device according to a second embodiment of the present invention. Reference numeral 30 denotes a holding member that supports the sheet-shaped pressing member 13, and reference numeral 31 denotes a recording paper conveyance in the holding member 30. The first extension 32 extends in an L-shape from both sides of the upstream end in the direction, and the second extension 32 extends in an L-shape from both sides of the downstream end of the holding member 30 in the recording paper conveyance direction. A projecting portion 33 is a first support portion that stands upright at a position upstream of the fixing roller 12 in the recording paper conveyance direction in the main body 1, and a portion between the fixing roller 12 and the first support portion 33 in the main body 1. The second support portion erected on the first support portion 35 is a rotating shaft for rotatably attaching the first extension portion 31 to the first support portion 33, the reference numeral 36 is an elongated hole formed in the second extension portion 32, and the reference numeral 37 is a third support portion. 2 extension part 32
Are fixed to the second support portion 34 via the elongated holes 36. Members having the same or the same functions as those in the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description is omitted.

One end of the sheet-shaped pressing member 13 is attached to the holding member 30 with a double-sided adhesive tape, and the holding member 30 is fixed to the first support portion 33 with the other end facing the recording paper conveying direction. ing.

When adjusting the nip pressure, the tilt angle of the sheet-shaped pressing member 13 is adjusted by rotating the holding member 30.
After adjusting the angle to a desired angle, the second extension 32 is fixed to the second support 34 by the screw 37,
The pressing amount of the sheet-shaped pressing member 13 against the fixing roller 12 when the fixing roller 12 is mounted is determined.

With this configuration, it is possible to adjust the pressing amount of the sheet-shaped pressing member 13 against the fixing roller 12, that is, the nip pressure.

FIGS. 5A and 5B are explanatory views showing the main configuration of a fixing device according to a third embodiment of the present invention. FIG. 5A is a side view, and FIG. 5B is a front view showing the configuration near a roller. , FIG. 5 (c)
Is an explanation showing the display surface of the dial. Reference numeral 38 denotes a roller having a rotating shaft at an eccentric position; 39, a dial for rotating the roller 38; 40, a bearing provided on the main body 1 and supporting the rotating shaft of the roller 38; Members having the same or the same functions as the members in the second embodiment shown in FIG. 4 are denoted by the same reference numerals, and detailed description is omitted.

In the fixing device of the third embodiment, the second extending portion 32 in the fixing device of the second embodiment is omitted, and
A bearing 40 is provided in place of the support portion 34, and this bearing 4
The supporting shaft of the roller 38 is supported by the roller 0, and the back surface of the holding member 30 is brought into contact with the roller 38.

The rotating shafts provided at both ends of the roller 38 are formed in the shape of a polygonal prism (square prism in the present embodiment), and the rotating shafts are used as receiving portions of a V-shaped bearing 40. A dial 39 is mounted on the rotary shaft 40a.

The four corners of the square pillar-shaped rotation shaft are located at a position A closest to the rotation shaft on the surface of the roller 38, a position B farthest from the rotation shaft, and an intermediate position C. That is, when the corner corresponding to the position A is engaged with the receiving portion 40a, the holding member 30 is pushed up to the highest position, and when the corner corresponding to the position B is engaged with the receiving portion 40a, the holding member 30 is held. When the member 30 is pushed up to the lowest position and the corner corresponding to the position C engages with the receiving portion 40a, the holding member 30 is pushed up to an intermediate position, so that three-stage position adjustment is possible. . Therefore, the pressing amount of the sheet-shaped pressing member 13 can be switched in three stages.

Further, as shown in FIG. 5 (c), the dial 39 displays a paper type corresponding to a three-stage pressing amount. Specifically, thick paper, plain paper, thin paper, and plain paper are displayed. Are displayed in the order of For example, when changing the paper type from plain paper to thick paper, the user rotates the dial 39 to select thick paper. At this time, the rotation shaft rotates from the state where the corner corresponding to the position C is engaged with the receiving part 40a, and the corner corresponding to the position A engages with the receiving part 40a, so that the click stops. Become like As a result, the sheet-shaped pressing member 13 is positioned at the highest position,
3, the pressure applied to the fixing roller 12 increases.

With this configuration, the pressure applied to the fixing roller 12 by the sheet-shaped pressing member 13 can be easily changed by a user's dial operation.
In addition, when the dial operation is performed normally, a click feeling is involved, so that the pressure can be reliably changed.

FIG. 6 is a side view showing a main structure of a fixing device according to a fourth embodiment of the present invention.
Is held by a bearing portion 41a.
a housing rotatable about b as a support shaft, a transmission gear for transmitting a driving force from a driving unit (not shown) for driving the fixing roller 12 to rotate, and a transmission gear 43 provided between the housing 41 and the housing, Fixing roller 12 to sheet-shaped pressing member 13
Is a sheet supporting member for supporting the sheet-shaped pressing member 13, and 45 is a stopper member of the sheet-shaped pressing member 13 attached to the supporting member. Members having the same or the same functions as the members in the second embodiment shown in FIG. 4 are denoted by the same reference numerals, and detailed description is omitted.

Reference numeral 46 denotes a movement for moving the fixing roller 12 to a contact position where a nip portion is formed between the sheet-shaped pressing members 13 and a position for moving the fixing roller 12 to a separated position where the sheet-shaped pressing members 13 are separated. Means. One end of the moving means 46 is engaged with an engaging claw 41c provided on the housing 41, and the other end is driven by a driving unit (not shown) for moving the contacting position and the separating position. Is provided. Further, in the direction in which the housing 41 is urged by the pressurizing means 43, the one-side pressure at the nip is 0.5 to 1
It has a locking means (not shown) for locking at a position where it is 0 (9.8N).

With this configuration, the nip pressure can be adjusted by moving the fixing roller 12 and changing the amount of deflection of the sheet-shaped pressing member 13.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described configuration. In the present embodiment, the sheet-shaped pressing member is brought into contact with the fixing roller, but, for example, a plurality of roller members provided with at least one heating source, and A fixing belt that circulates by rotation, has one end of a sheet-shaped pressing member in contact with a part of the fixing belt, and fixes the other end to the upstream side in the circulation direction of the fixing belt, so that a toner image is formed. The present invention is applied to a fixing device that fixes a toner image on a recording sheet by applying pressure / heating when the transferred recording sheet is passed between a fixing belt and a sheet-shaped pressing member, and moves the sheet-shaped pressing member. Then, the pressure applied from the sheet-shaped pressing member to the fixing belt may be adjusted.

Alternatively, a cylindrical fixing member made of a flexible member, driving means for circulating the fixing member,
It has a heating source abutting on the inside of the fixing member, and a sheet-shaped pressing member abutting on the heating source via the fixing member, and conveys one end of the sheet-shaped pressing member to the heating source with respect to the recording paper. The recording paper, on which the toner image has been transferred, is pressed against the heat source by pressing the sheet-shaped pressure member against the heat source via the fixing member. The present invention is applied to a fixing device for fixing a toner image on recording paper by applying pressure / heating when passing between members, and moving a sheet-shaped pressing member to apply a heating source from the sheet-shaped pressing member. The pressure may be adjusted.

[0057]

According to the present invention having the above-described structure, the pressure applied to the nip between the fixing roller, the fixing belt or the heat source and the sheet-shaped pressing member can be adjusted. Paper transportability can be maintained.

Further, since the nip pressure can be made variable, the nip pressure can be selected according to the thickness of the recording paper. As a result, the occurrence of transport failure due to the thickness of the recording paper can be reduced. It becomes possible to reduce.

[Brief description of the drawings]

FIG. 1 is a side view showing an internal configuration of a facsimile apparatus having a fixing device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a fixing device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a schematic configuration of a pressure adjusting mechanism in FIG. 2;

FIG. 4 is a side view showing a configuration of a fixing device according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating a configuration of a fixing device according to a third embodiment of the present invention.

FIG. 6 is a side view illustrating a configuration of a fixing device according to a fourth embodiment of the present invention.

FIG. 7 is a side view showing the internal structure of a conventional fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Process cartridge 3 Photoreceptor 4 Optical writing device 5 Paper supply cassette 6 Paper supply roller 7 Transfer roller 8 Fixing device 9 Discharge roller 10 Adhesion sensor 11 Original mounting table 12 Fixing roller 13 Sheet pressing member 14 Heat source 15 Guide Plate 20 Coil Spring 21 Pressure Adjusting Mechanism 22 Mounting Plate 23 Pedestal 24 Screw Hole 25 Solenoid 30 Holding Member 31 First Extension 32 Second Extension 33 First Support 34 Second Support 35 Rotating Shaft 36 Slot 37 Screw 38 Roller 39 Dial 40 Bearing part 40a Receiving part 41 Housing 42 Transmission gear 43 Pressurizing means 44 Sheet support material 45 Stopper member 46 Moving means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasushi Kiuchi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Kota Takenaka 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh F term (reference) 2H033 AA06 AA15 AA37 AA47 BA11 BB18 BB33 BB34 BB35 BB36 BB37 BB38 CA39

Claims (17)

[Claims] 1. A fixing device comprising: a cylindrical fixing roller having a heating source therein; and a sheet-shaped pressing member which abuts on the fixing roller and presses the fixing roller by a leaf spring property of the sheet-shaped pressing member. Then, when the recording paper on which the toner image has been transferred is passed through a nip portion formed between the fixing roller and the sheet-like pressing member, pressure / heating is applied to fix the toner image onto the recording paper. A fixing device for moving the sheet-shaped pressing member and adjusting a pressure applied to the fixing roller from the sheet-shaped pressing member. 2. An urging member disposed between the sheet-shaped pressing member and the main body, and urging the sheet-shaped pressing member toward the fixing roller, and the urging member. 2. The fixing device according to claim 1, further comprising a drive control unit that moves a lower portion of the member up and down. 3. The device according to claim 2, wherein the biasing member is a coil spring having one end for biasing the back side of the sheet-shaped pressing member and the other end attached to the drive control means. Fixing device. 4. The fixing device according to claim 3, wherein a plurality of said coil springs are arranged, and said drive control means simultaneously changes the positions of the other ends of all the coil springs. 5. The fixing device according to claim 4, wherein the drive control unit includes an adjustment unit that adjusts an initial position of each other end of the coil spring. 6. An end of the coil spring is attached to the back side of the sheet-shaped pressing member, and the drive control means releases the coil spring so as to release a contact state between the sheet-shaped pressing member and a fixing roller. The fixing device according to claim 2, wherein the position of the other end of the fixing device is changed. 7. A pressure adjusting device comprising: a supporting portion for rotatably supporting a fixed end of the sheet-shaped pressing member; and an adjusting portion for vertically moving a free end of the sheet-shaped pressing member. The fixing device according to claim 1, wherein the fixing device is configured. 8. An extension part formed in a part of the support part, and a screw member inserted into an elongated hole formed in the extension part to fix the extension part to a main body. The fixing device according to claim 7, wherein the fixing device comprises: 9. The apparatus according to claim 1, wherein said adjusting portion comprises a roller body abutting on said support portion and having an eccentric rotating shaft, and a bearing portion supporting said rotating shaft of said roller body. 8. The fixing device according to 7. 10. The fixing device according to claim 9, wherein the rotating shaft is a polygonal column, and the bearing is a concave portion adapted to the rotating shaft. 11. The fixing device according to claim 9, wherein a dial member displaying an index of a rotational position corresponding to a vertical position of the sheet-shaped pressing member is provided on the rotating shaft. 12. The fixing device according to claim 11, wherein the index is a thickness of a recording sheet corresponding to a vertical position of the sheet-shaped pressing member. 13. A fixing device comprising: a cylindrical fixing roller having a heat source therein; and a sheet-shaped pressing member that abuts on the fixing roller and presses the fixing roller by a leaf spring property of the sheet-shaped pressing member. Then, when the recording paper on which the toner image has been transferred is passed through a nip portion formed between the fixing roller and the sheet-like pressing member, pressure / heating is applied to fix the toner image onto the recording paper. A fixing device, comprising: a pressure adjusting unit configured to adjust a pressure applied from the sheet-shaped pressing member to the fixing roller by moving a position of the fixing roller. 14. A plurality of roller members provided with at least one heat source, a fixing belt stretched by these roller members, and circulating by the rotation of the roller members.
A sheet-shaped pressing member that abuts a part of the fixing belt, and when the recording paper on which the toner image has been transferred passes through a nip portion formed between the fixing belt and the sheet-shaped pressing member. A fixing device for fixing a toner image on recording paper by pressurizing / heating the recording medium, wherein the pressure for moving the sheet-shaped pressing member and adjusting the pressure applied from the sheet-shaped pressing member to the fixing belt is adjusted. A fixing device comprising an adjusting unit. 15. A fixing member having a cylindrical shape made of a flexible member, driving means for circulating and moving the fixing member, a heating source in contact with the inside of the fixing member, and a heating source interposed through the fixing member. And pressurizing / heating the recording paper, onto which the toner image has been transferred, when passing through a nip formed between the heating source and the sheet-shaped pressing member. A fixing device for fixing the toner image on the recording sheet by moving the sheet-shaped pressing member to adjust a pressure applied to the heating source from the sheet-shaped pressing member. A fixing device. 16. The fixing device according to claim 1, wherein the sheet-shaped pressing member is provided so as to be cantilevered with respect to a nip portion on an upstream side in a recording paper conveyance direction. apparatus. 17. An image forming apparatus comprising the fixing device according to claim 1. Description: