JP2003330308A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent cleaning failure, reverse flow, peel, etc., of recovered matter, in cleaning of a fixing device. <P>SOLUTION: A trapezoidal gear is brought into contact with the reciprocal shaft of the cleaning roller of the fixing device and rotated by a drive motor, thereby reciprocally moving the cleaning roller. Because soil can be uniformly recovered by the operation even in case where, for example, a certain area is soiled, cleaning performance is ensured for a long time, and peel, reverse flow, etc., of recovered toner and so on are prevented. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device which heats a toner image by applying thermal energy to a recording material carrying a visible image (toner image) to be heat-fixed.

[0002]

2. Description of the Related Art Conventionally, a means using a heat roller is known as a means for fixing a visible image on a recording paper. There were drawbacks such as lengthening. On the other hand, a fixing method using a heat-resistant film for improving this drawback is described in JP-A-63-313182.

The fixing device described in this publication includes a thin heat-resistant film, a drive roller for the film, and a heating element fixedly supported so as to be in sliding contact with the inner peripheral surface of the film. And a pressing member arranged so as to come into contact with the outer peripheral surface of the film and come into pressure contact with the heating body via the film.

The film and the pressure member are rotated at substantially the same speed as the conveying speed of the recording material at least during image fixing, and the heating member and the pressure member formed through the film are fixed. When the recording material is nipped and conveyed at the nip, a visible image on the recording material (unfixed toner image)
The visible image is softened and melted by applying the heat energy of the heating element to the recording medium, and then the recording material is discharged from the fixing nip portion to be cooled and solidified to be fixed on the recording material. .

Since this film fixing system has a very short warm-up, it is not necessary to preheat the heating element (so-called standby temperature control), and energy saving can be realized.

Here, a rotary cleaning member having a low heat capacity is brought into contact with the pressure roller to remove the residual toner and prevent the pressure roller from being contaminated with the recording material.

That is, by forming the rotary cleaning member with a material having high thermal conductivity, the rotary cleaning member is brought into contact with the pressure roller, so that the pressure roller is not only cleaned but also the non-sheet passing portion Prevents excessive temperature rise and makes the temperature distribution uniform, improving the durability of the fixing film and pressure roller, preventing offset,
The deviation control of the fixing film can be stabilized.

[0008]

However, in the rotary cleaning member of the conventional fixing device, when the same image such as a standard format is printed, the dirt is collected at a certain position and the surface of the rotary cleaning member becomes uneven. There was an opening problem in which the cleaning effect mainly on the recesses was significantly reduced.

[0009]

According to the present invention for solving the above-mentioned problems, a heating means, a pressing means for a roller body pressed against the heating means, and a rotation cleaning means contacting with the pressing means are provided. In a fixing device for carrying and fixing a recording material carrying an unfixed image at a pressure contact portion of the heating means and the pressure means, the rotation cleaning means is different depending on a reciprocating movement condition. is there.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a diagram showing a schematic configuration of an example of an image forming apparatus using the fixing device 60 of this embodiment. As shown in FIG. 1, the image forming apparatus according to the present embodiment is a fixed document table, an optical system moving type, a rotating drum type, and a transfer type electrophotographic copying apparatus. In the apparatus of the present embodiment, as shown in FIG. 1, the original 19 is placed on the fixed original glass 20 as required, the required copying conditions are set, and then the copy start key is pressed. 39 is rotationally driven in the clockwise direction indicated by the arrow at a predetermined peripheral speed. Further, the light source 21 (22 is a reflection shade) and the first mirror 23 move along the lower surface of the document table glass 20 from the home position on the left side of the glass to the right side of the glass at a predetermined speed V, and the second mirror 24, By moving the 3 mirror 25 in the same direction at a speed of V / 2, the downward image surface of the document 19 placed on the document glass 20 is illuminated and scanned from the left side to the right side, and the document surface of the illumination scanning light is scanned. The reflected light is formed by the imaging lens 29, the fixed fourth to sixth mirrors 26, 2.
Image formation exposure (slit exposure) is performed on the surface of the rotating photoconductor drum 39 via 7, 28.

The surface of the rotating photosensitive drum 39 is uniformly charged to the predetermined positive or negative potential by the primary electricity 30 on the exposed surface, and the above-mentioned exposure is performed on the charged surface. Thus, an electrostatic latent image having a pattern corresponding to the original image is sequentially formed on the surface of the drum 39. The electrostatic latent image formed on the surface of the photosensitive drum 39 is visualized as a toner image by the developing roller 32 of the developing device 31.

On the other hand, the recording material P is fed by the paper feed roller 51, introduced into the transfer group between the drum 39 and the transfer charger 34 at a predetermined timing through the guide 33, and receives the transfer corona. The toner visible image on the drum 39 surface side is sequentially transferred to the upper surface of the recording material in contact with the drum 39.

The recording material P that has passed through the image transfer portion is charged with a charge eliminating needle 35.
While being subjected to the removal of the electric charges on the back surface by the drum 39, they are sequentially separated from the surface of the drum 39, introduced into the fixing device 60 by the transport unit 38 and the entrance guide 10, and subjected to toner image fixing as described later, and then transferred outside the apparatus as an image-formed product. Is discharged.

After the transfer, the surface of the drum 39 is cleaned and removed by the cleaning blade 37 of the cleaning device 36 to remove the residual toner and other stains, and is repeatedly used for image formation.

As described above, the moving optical members 21 to 25, which have moved on the outward path, are set so as to move on the return path when they reach the predetermined outward path end point, return to the initial home position, and start the next copy cycle. Wait until (below,
This step is referred to as the back step of the optical system).

When a plurality of copies (for example, 100 copies) is designated before the copy start key is pressed, the above steps are repeated at predetermined intervals after the back step of the optical system is completed.

Next, the fixing device 60 mounted on the apparatus of this embodiment will be described in detail with reference to FIG. In FIG. 2, 100 is a heating means, 200 is a pressure means, and 6 is an endless belt-shaped fixing film. The fixing film 6 has a left driving roller 7, a right driven roller 8, and both rollers 7, 8. It is stretched between the low-heat-capacity linear heater 1 which is a heating element fixedly arranged below the space.

The driven roller 8 also serves as a tension roller for applying a tension in the direction of stretching the fixing film 6 to the outside. The fixing film has a surface coated with silicone rubber or the like to increase the friction coefficient in the clockwise direction of the driving roller 7. Along with the rotational drive, there are wrinkles and meanders in a clockwise direction at a predetermined peripheral speed.
It is driven to rotate without speed delay.

Reference numeral 9 denotes a pressure roller having a rubber elastic layer having a good releasability, such as silicone rubber, which is one of the elements constituting the pressure means, and is the lower film portion of the endless belt-shaped fixing film 5. Is sandwiched between the heater 1 and the heater 1, and a biasing means such as a spring is applied to the lower surface of the heater 1.
For example, they are pressed against each other with a contact force of 5 to 10 kg, and rotate in the forward counterclockwise direction in the conveying direction of the recording material P. Further, in the pressure roller, the diameter of the end portion in the longitudinal direction is larger by 50 to 500 μm than the diameter of the central portion in the longitudinal direction. As a result, it is possible to prevent the recording paper P from being wrinkled due to the force of pulling the recording paper P toward the end side in the fixing nip.

Reference numeral 13 denotes a cleaning roller which is a cleaning means arranged so as to sway on the pressure roller 9. The cleaning roller is formed of an aluminum rod, and a biasing means supporting member 14 such as a spring is provided. For example 20
Opposing pressure is applied with a contact force of 0 to 2000 g.

In this embodiment, a reciprocating mechanism for reciprocating the paper pressure roller 9 in the vertical direction is provided.

Since the endless fixing film 6 which is rotationally driven is repeatedly subjected to heat fixing of the toner image, it is excellent in heat resistance, releasability and durability, and generally 10
A thin wall having a thickness of 0 μm or less, preferably 40 μm or less is used. As an example, a highly heat-resistant resin such as polyimide, polyetherimide, polyethersulfone, polyether, or etherketone having a thickness of 20 μm, nickel, or SU.
PTFE on the outer peripheral surface of a thin endless belt made of metal such as S
(Tetrafluoroethylene resin), PFA (Tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin)
A low surface energy resin such as or a release coating layer in which a conductive material such as carbon black is added to these resins.
It is an endless belt having a total thickness of 30 μm applied to a thickness of 0 μm. The fixing belt may be endless.

The heater 1 having a low heat capacity has a thickness of 1.0, for example.
mm, a width of 10 mm, and a longitudinal length of 340 mm, a resistive material such as silver palladium or ruthenium oxide is applied to a thickness of 10 μm and a width of 1.0 mm to form a heat generating layer 3 on the alumina substrate 2. There is a protective layer 4 formed of glass or the like in consideration of sliding with the film 6 having a thickness of 10 μm.
The heater support 11 is attached and held to be fixedly supported.

The heater support 11 is a material having a heat insulating property, a high heat resistance, and a rigidity that heat-insulates and supports the heater 1 with respect to the fixing device 60 and the image forming device. For example, PPS (polyphenylene sulfide), PEEK (polyether ether). (Ketone), liquid crystal polymer, or other high heat resistant resin, or a composite material of these resins and ceramics, metal, or the like.

The heating layer 3 of the heater is energized from both ends in the longitudinal direction. The energization is 100 V AC, and the energization is controlled by the micro computer according to the detection temperature of the thermistor 5 such as an NTC thermistor or the like which is bonded or pressure-bonded to the back surface of the substrate 2 with a heat conductive silicone rubber adhesive or the like. To be done.

Next, by the image forming operation as described above,
The recording material P having the unfixed toner image T transferred onto the upper surface thereof is guided by the guide 10 and enters the fixing nip portion of the heater 1 and the pressure roller 9 formed via the fixing film 6, and the unfixed toner image T is formed. Ta closely adheres to the lower surface of the fixing film 6 to cause surface deviation, passes through the fixing nip portion N while receiving a pinching pressure in the overlapping state with the fixing film 6 without causing wrinkles and deviations, and the recording material P The toner image bearing surface receives the heat of the heat generating layer 3 through the fixing film 6 while passing through the fixing nip portion N in a pressure fixing state on the fixing film surface, the toner image is melted at a high temperature, and is softened on the recording material P surface. The image Ta becomes an adhesive. In the case of the apparatus according to the present embodiment, the recording material P and the fixing film 6 are separated at the time when the recording material P passes through the fixing nip portion N and exits. The temperature is still higher than the glass transition point of the toner. The toner Ta, which is at a temperature higher than the glass transition point at this separation point, has an appropriate rubber characteristic, so that the toner image surface at the time of separation has an appropriate uneven surface property without following the fixing film surface. However, since the surface property is maintained and the solidified material is cooled and solidified, an excessive image gloss does not occur on the fixed toner image surface, and a high quality image is obtained. The recording material P separated from the fixing film 6 is guided by the paper discharge guide 12 and reaches the paper discharge roller pair 15 by naturally lowering the temperature of the toner Ta (higher than the glass transition point) (natural cooling). When the temperature reaches the following, the temperature is lowered and the image Tb is reached.

Among the heaters 1 in this embodiment,
Since the heat generation layer 3 and the substrate 2 have small heat capacities and they are adiabatically supported by the heater support 11, the surface temperature at the fixing nip portion N of the heater 1 rises to a sufficiently high temperature with respect to the melting point of the toner in a short time. Since the temperature is raised, it is not necessary to raise the temperature of the heater 1 in advance (so-called standby temperature adjustment), energy can be saved, and the temperature rise inside the machine can be prevented.

By the way, the cleaning roller 13 according to the embodiment of the present invention is made of aluminum having an outer diameter of 12 mm, and its surface is roughened to Ra = 2.4 μm in order to improve the cleaning property. The cleaning roller 13 is supported by the slide bearing 14.

The cleaning roller in this embodiment is
As shown in FIG. 3, the pressure roller 200 is provided with a reciprocating mechanism for reciprocating in the vertical direction.

That is, the cleaning roller 61 is reciprocally moved along the reciprocating shaft 62 in a direction perpendicular to the pressure roller 200 by a drive motor (not shown) so that the cleaning roller 61 is in contact with the surface of the pressure roller 200. By mechanically reciprocating in the vertical direction, even if the same image or the like is printed in large numbers, even uneven toner stains on the pressure roller 200 can be evenly collected on the surface of the cleaning roller 61, and reliability can be improved. A high cleaning effect can be obtained. The other end (left side in the drawing) of the reciprocating shaft 62 is in contact with the inclined side surface of the trapezoidal gear 63. This trapezoidal gear 63 is rotationally driven by a drive gear 64 which is rotationally driven by a drive motor (not shown), and reciprocates the reciprocating shaft 62 in the directions of arrows F and R in the figure by a distance L corresponding to the difference in the gear width of the trapezoidal gear 63. Is configured.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG.

The difference from the first embodiment is that, as shown in FIG. 4, in the fixing device, the fixing roller 203 is an aluminum metal cylindrical roller having a thickness of 364 mm and a thickness of 2.9 mm, and is 25 μm.
It is made of a thick PFA coating to improve releasability, and its outer diameter is 27.8 mm. A 600 W halogen heater 202, which is a heat source, is provided inside the fixing roller 203.
On the surface of 3, the surface of polyimide material is 25 μm thick PF
The A-coated separation claw 206, the fixing pad 205, and the thermistor 201 are arranged so as to come into contact with each other.

On the other hand, a pressure roller 204 is arranged below the fixing roller 203. The pressure roller 204 is for forming a nip (pressure contact portion) in the heat fixing portion, and a PFA tube (volume resistance 1
0 ¹³ to 10 ¹⁴ Ω · cm), a conductive (volume resistance 10 ³ to 10 ⁴ Ω · cm) silicone sponge as a lower layer, a core bar of iron with an outer diameter of 14 mm, and a length of 317 mm (rubber part), It has an outer diameter of 27 mm and a hardness of 41 ° (ASKER-C hardness). Then, the pressure roller 20
In the fixing roller 2, both ends of the core metal are fixed by springs (not shown).
Total pressure 13kgf of 6.5kgf on one side toward the center of 03
The core metal of each roller is supported by the bearing of the bearing and is rotationally driven by the print main motor. The peripheral speed is rotating at 94.5 mm / sec. Further, 13 which is in contact with the pressure roller 303 is a cleaning roller which is a cleaning means, and the cleaning roller is formed of an aluminum rod, and is 200 to 200 by a biasing means supporting member 14 such as a spring. The contact force of 2000 g is applied to sway the opposite.

The cleaning roller in the embodiment is provided with a reciprocating mechanism for reciprocating the pressure roller 200 in the vertical direction.

That is, the cleaning roller 61 is reciprocated in the direction perpendicular to the pressure roller 200 along the reciprocating shaft 62 by a drive motor (not shown), and the cleaning roller 61 is brought into contact with the surface of the pressure roller 200. By mechanically reciprocating in the vertical direction, even if the same image or the like is printed in large numbers, even uneven toner stains on the pressure roller 200 can be evenly collected on the surface of the cleaning roller 61, and reliability can be improved. A high cleaning effect can be obtained. The other end (left side in the drawing) of the reciprocating shaft 62 is in contact with the inclined side surface of the trapezoidal gear 63. This trapezoidal gear 63 is rotationally driven by a drive gear 64 which is rotationally driven by a drive motor (not shown), and reciprocates the reciprocating shaft 62 in the directions of arrows F and R in the figure by a distance L corresponding to the difference in the gear width of the trapezoidal gear 63. Is configured.

According to an experiment conducted by the present inventor based on the above structure, the cleaning roller 61 is set to 10 mm / sec.
When a reciprocating movement mechanism that reciprocates L = 10 mm at the speed of 1 was provided, the occurrence of cleaning failure could be significantly reduced.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG.

The difference from the first embodiment is that, as shown in FIG. 5, the fixing device slides the film 302 in contact with the heating element 301, and the surface of the film 302 opposite to the heating element 301 is covered. The heating material (recording material) P is brought into close contact with the film 30.
The heating element 301 passes through the heating element 301 together with the heating element 301, and heat energy is applied from the heating element 301 to the heating target material P via the film 302. The heating target material P is driven by the motor M as a member for pressing and transporting the heating target material P to the film 302. Pressure roller 303
Is equipped with. Further, 13 which is in contact with the pressure roller 303 is a cleaning roller which is a cleaning means, and the cleaning roller is formed of a rod made of aluminum, and is composed of, for example, 2 by a biasing means supporting member 14 such as a spring.
Opposing pressure is applied with a contact force of 00 to 2000 g.

The cleaning roller in the embodiment is provided with a reciprocating mechanism for reciprocating the pressure roller 200 in the vertical direction.

That is, the cleaning roller 61 is reciprocated in the direction perpendicular to the pressure roller 200 along the reciprocating shaft 62 by a drive motor (not shown), and the cleaning roller 61 is swung on the surface of the pressure roller 200. By mechanically reciprocating in the vertical direction, even if the same image or the like is printed in large numbers, even uneven toner stains on the pressure roller 200 can be evenly collected on the surface of the cleaning roller 61, and reliability can be improved. A high cleaning effect can be obtained. The other end (left side in the drawing) of the reciprocating shaft 62 is in contact with the inclined side surface of the trapezoidal gear 63. This trapezoidal gear 63 is rotationally driven by a drive gear 64 which is rotationally driven by a drive motor (not shown), and reciprocates the reciprocating shaft 62 in the directions of arrows F and R in the figure by a distance L corresponding to the difference in the gear width of the trapezoidal gear 63. Is configured.

The structure for changing the reciprocating movement speed of the cleaning roller 61 can be easily realized by changing the rotation speed of the drive motor for each image forming section or changing the number of teeth of the drive gear 64. You can

According to the experiments conducted by the present inventor, although the moving distance L for reciprocating the cleaning roller in contact with the pressure roller is increased, the ability of the cleaning roller to remove the adhered toner from the pressure roller can be improved. Was found to improve.

[0043]

As described above, the heating means, the pressing means for the roller body pressed against the heating means, the rotation cleaning means in contact with the pressing means, the heating means and the pressing means. In a fixing device that carries and fixes a recording material carrying an unfixed image at a pressure contact portion, the rotation cleaning means is made different according to the reciprocating movement condition, so that toner etc. unevenly adhered on the pressure roller is removed. It is possible to collect evenly on the cleaning roller, and it is possible to eliminate the attenuation of the cleaning effect due to the unevenness of the surface. This has the effect of prolonging the life of the device and achieving maintenance-free operation.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an image forming apparatus section including a fixing device of the present invention.

FIG. 2 is a schematic configuration diagram of a fixing device incorporating the device of FIG.

FIG. 3 is a schematic configuration diagram of a reciprocating cleaning roller of the present invention.

FIG. 4 is a schematic configuration diagram of a fixing device according to a second embodiment of the invention.

FIG. 5 is a schematic configuration diagram of a fixing device according to a third embodiment of the invention.

[Explanation of symbols]

6 fixing film 9 Pressure roller 13, 61 Cleaning roller 14 bearings 16 dirt stopper 62 reciprocating shaft 63 trapezoidal gear 64 drive gear 100 heating means 200 Toner of pressure applying means Tc

Claims (3)

[Claims] 1. An unfixed image by heating means, pressure means for pressing a roller body pressed against the heating means, rotation cleaning means in contact with the pressure means, and pressure contact between the heating means and the pressure means. In a fixing device for sandwiching and carrying a recording material carrying a sheet, and fixing the rotating cleaning means, the rotating cleaning means is made different according to a reciprocating movement condition. 2. The fixing device according to claim 1, wherein the heating unit has a heating body and an endless or endless film that slides on the heating body. 3. The fixing device according to claim 1, wherein the heating unit has a cylindrical roller and a heating body disposed inside the roller.