JPH10221987A - Fixing device and image forming device - Google Patents

Abstract

(57) Abstract: A curl correction comprising a plurality of rollers in a transport path downstream of a nip portion 110 formed by a heating body 105 and a pressure roller 109 via a thin film 102 and separated from the nip portion. Since the recording medium 107 that has passed through the nip portion is cooled and then acts on the curl correcting unit because of the provision of the unit 114, the curl reduction effect is low and the configuration is complicated. SOLUTION: On the downstream side of a nip portion 10 formed by a heating element 5 and a pressure roller 9 via a thin film 2,
By the roller member 14 which comes into contact with the thin film and is rotated by the running of the thin film, the recording medium sent out from the nip portion is curled in a direction opposite to that of the pressure roller. This roller member is provided on the separation claw 12 rotatably attached to the paper ejection guide 11 or the separation claw 18b formed integrally with the paper ejection guide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for fixing a visible image formed on a recording material to the recording material, and more particularly to a fixing device using a thin film film and a copier and a printer to which the fixing device is applied. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art FIG. 11 is a side view showing a conventional fixing device. In the figure, 101 is an apparatus case, 102 is guide rollers 103, 10 arranged at each vertex of a substantially triangle.
4. An endless heat-resistant thin film suspended around a stay 106 to which a heating element 105 is attached. Reference numeral 107 denotes a recording sheet as a recording medium conveyed from a transfer unit (not shown) of the image forming apparatus along an entrance guide 108, and 109 forms a nip 110 with the heating body 105 and passes through the nip 110. The pressing roller is a pressing roller that presses the recording paper 107 to be pressed against the heating element 105, and is rotationally driven in a direction indicated by an arrow by driving means (not shown). Reference numeral 111 denotes a discharge guide provided on the downstream side of the nip portion 110 in the recording paper conveyance direction. Reference numeral 112 denotes a separation claw that is rotatably supported on the discharge guide 111 by a shaft 113. The elastic member is pressed against the surface of the pressure roller by the elastic force of the spring member. 114
Is the driving roller 115 and the recording paper 10 along the driving roller 115
And a guide roller 116 for transporting the sheet 7.

Next, the operation will be described.

When an image forming apparatus (not shown) to which the fixing device having the above configuration is applied is operated, the pressure roller 109 is driven in the direction of the arrow, and the thin film 102 is moved in the direction of the arrow by receiving the frictional driving force of the pressure roller 109. And heated by the heating element 105 when passing through the nip 110.

In this state, the recording paper 107 conveyed from the transfer section of the image forming apparatus (not shown) along the entrance guide 108 is pressed by the pressing roller 1 when passing through the nip section 110.
09 through the thin film 102 and the heating element 105
And the visible image formed on the surface is heated 10
5 and heat-fixed to the surface. When the recording paper 107 passes through the nip 110, the recording paper 107 is curled toward the pressure roller 109, that is, downward in the illustrated example, so that a jam may occur in the transport path downstream of the surf fixing device. Was.

Therefore, the conventional fixing device is provided with a curl correcting means 114 in the downstream conveying path, and the curl correcting means 114 imparts an upward curl to the recording paper 107 to cancel the downward curl. Curls are straightened.

[0007]

However, in the above-mentioned conventional example, since the curl correcting means 114 is located at a position distant from the nip portion 110, the recording paper 107 is moved to the nip portion 110.
Is cooled to some extent before it reaches the curl correcting means 114 after passing through. For this reason, there is a problem that the curl correcting effect is reduced. In addition, since the curl correcting unit 114 includes a plurality of rollers, there is a problem that the configuration is complicated.

The present invention has been made in order to solve the above-mentioned conventional problems, and is to correct the curl immediately after the recording paper has passed through the nip portion, that is, before the recording paper is cooled. It is another object of the present invention to provide a fixing device that can enhance the curl correction effect, secure stable paper conveyance performance, and realize curl correction with a simple configuration.

[0009]

According to a first aspect of the present invention, there is provided a fixing device for heating a recording body through a thin film, and connecting the recording body to the heating body through the thin film. In a fixing device having a pressure roller for applying pressure, a downstream side of a nip portion formed by the heating element and the pressure roller through the thin film, abuts on the thin film and is driven by the running of the thin film. And a roller member for imparting curl in the opposite direction to that of the recording medium sent from the nip portion by the pressure roller.

The fixing device according to the second aspect of the present invention provides
A discharge guide disposed downstream of the nip portion; and a separation claw that is urged to contact the leading end with the pressure roller and is rotatably provided on the discharge guide. The separation claw is provided with a roller member that rotates following the thin film running and imparts curl to the recording medium sent from the nip in a direction opposite to that in the case of the pressing roller.

According to a third aspect of the present invention, there is provided a fixing device.
A paper ejection guide and a separation claw are provided integrally, and the tip of the separation claw is urged so as to abut against a pressure roller, and the paper ejection guide is rotatably attached to the case side plate. The separation claw is provided with a roller member that rotates following the film running and imparts curl to the recording medium sent from the nip in a direction opposite to that in the case of the pressing roller.

The thin film of the fixing device according to the present invention is a heat-resistant film.

The film thickness of the heat-resistant film of the fixing device according to the present invention is 100 μm or less.

According to a sixth aspect of the present invention, there is provided an image forming apparatus, wherein the image forming means and the recording medium sent from the image forming means are heated to fix the visible image formed on the recording medium. A fixing device according to any one of claims 1 to 5 is provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below.

Embodiment 1 FIG. 1 is a side view showing the structure of a fixing device according to Embodiment 1 of the present invention, FIG. 2 is a plan view taken along line II of FIG. 1, and FIG. FIG. 1 is a perspective view showing the endless device, in which 1 is an apparatus case, 2 is an endless shape suspended on guide rollers 3 and 4 disposed at each vertex of a substantially triangular shape, and a stay 6 to which a heating element 5 is attached. It is a heat-resistant thin film. Reference numeral 7 denotes a recording sheet as a recording medium conveyed from a transfer unit of an image forming apparatus (not shown) along an entrance guide 8, and 9 forms a nip 10 between the recording medium and the heating element 5, and passes through the nip 10. The pressure roller is a pressure roller that presses the recording paper 107 against the heating element 105. The case side plates 1a,
1b is rotatably supported, and is driven to rotate in the direction of the arrow by a driving means (not shown). Reference numeral 11 denotes a discharge guide provided on the downstream side of the nip portion 10 in the recording paper conveyance direction. Reference numeral 12 denotes a separation claw that is rotatably supported by the discharge guide 11 with a shaft 13. The elastic member is pressed against the surface of the pressure roller by the elastic force of the spring member.

Reference numeral 14 denotes a curl removing roller member which is positioned slightly behind the tip of the separation claw 12 and is rotatably supported by the separation claw. The curl removing roller member 14 is provided on the discharge side curved surface portion 6a of the stay 6 via the thin film 2. The film 2 rotates in accordance with the movement of the film 2 in the direction of the arrow.

The thin film 2 has a thickness of 1 to reduce the heat capacity and improve the quick start.
00 μm or less, preferably 50 μm or less 20 μm or more heat-resistant single-layer film such as PTFE, PFA, FEP, or polyimide, polyamide imide, PEEK,
PTFE, PPS on the outer surface of the film such as PES, PPS
A composite layer film coated with FA, FEP or the like is used. In this example, PT
One coated with FE was used.

FIG. 4A omits a part of the heating element 5.
FIG. 3B is a partially cutaway plan model view, and FIG. The heating element 5 is an elongated heat-resistant, insulating, and heat-conductive substrate 51 whose longitudinal direction is perpendicular to the transport direction a of the thin film 2 or the recording paper 7 as the object to be heated. , A resistance heating element 52 formed along the longitudinal direction of the substrate, a heat-resistant overcoat layer 54 that protects the surface of the heating element on which the resistance heating element is formed, and both longitudinal ends of the resistance heating element 52. Is a linear heating element having a low heat capacity as a whole, including a power supply electrode 53, a temperature detecting element 55 such as a thermistor for detecting the temperature of the heating element provided on the back side of the substrate.

The heating element 5 is fixedly disposed so that the surface on which the resistance heating element 52 is formed is exposed face-up and held on the lower surface of a rigid and heat-resistant stay 6.

The substrate 51 of the heating element 5 is made of, for example, alumina or aluminum nitride having a thickness of 1 mm and a width of 10 mm.
The length is 330 mm. The resistance heating element 52 is made of, for example, an electric resistance material such as Ag / Pd (silver palladium), RuO ₂ , Ta ₂ N by screen printing or the like, and has a thickness of about 10 mm.
It is formed by coating in a linear shape or a narrow band shape having a width of 1 μm and a width of 1 to 3 mm.

The power supply electrodes 53 are screen printing pattern layers made of, for example, Ag. Overcoat layer 54
Is, for example, a heat-resistant glass layer having a thickness of about 10 μm.

The pressure roller 9 comprises a core metal 9a, an elastic layer 9b made of silicon rubber or the like, and an outermost release layer 9c. The thin film 2 is pressed with a predetermined pressing force by bearing means and biasing means (not shown). It is disposed so as to be pressed and pressed against the surface of the heating element 3. The thin film 2 is driven to rotate by the frictional force between the roller and the outer surface of the thin film caused by the rotation of the pressure roller 9.

Next, the operation will be described.

When an image forming apparatus (not shown) to which the fixing device having the above-described structure is applied is operated, the pressure roller 9 rotates in the direction of the arrow, and the thin film 2 is moved by the arrow due to the frictional driving force of the pressure roller 9. Move in the direction. The temperature of the heating element 5 is increased by the heating of the resistance heating element 52 over the entire length thereof by supplying power to the power supply electrodes 53 at both longitudinal ends of the resistance heating element 52, and the temperature increase is detected by the temperature measuring element 55. You. A / D conversion of the output of the temperature detecting element 55
By controlling the phase and frequency of the AC voltage of the AC power supply 17 for energizing the resistance heating element 52 by the triac 16 based on the information, the energizing power to the heating element 5 is controlled to control the heating temperature. You.

That is, by controlling the energization so that the temperature of the heating element 5 rises when the temperature detected by the temperature detecting element 55 is lower than a predetermined set temperature, and to lower the temperature when the temperature is high, the heating element 5 is heated. The body 5 is controlled at a constant temperature during fixing. Thus, the heating element 5 is heated by the heating material 5 when passing through the nip 10 in a state where the temperature of the heating element 5 rises to a predetermined value and the rotation peripheral speed of the thin film 2 due to the rotation of the pressure roller 5 is stabilized.

In this state, the recording paper 7 conveyed from the transfer section of the image forming apparatus along the entrance guide 8 is pressed against the heating element 5 via the thin film 2 by the pressure roller 9 when passing through the nip section 10. Then, the visible image on the surface heated by the heating element 5 is fixed by heating. When the recording paper 7 passes through the nip portion 10, curl is applied to the pressure roller 9 side, in the illustrated example, downward, but immediately thereafter, that is, before the recording paper 2 is almost cooled, Is pressed by the curl removing roller member 14 via the thin film film moving to the discharge side curved surface portion 6a of the stay 6, and is fed by the movement of the thin film film and the roller member 14 which is driven and rotated by the thin film film. A curl in the direction is applied. As a result, the curl in the downward direction imparted when passing through the nip portion 10 is effectively canceled.

As described above, according to the first embodiment, the curl imparted to the recording paper 7 can be effectively eliminated by a simple and inexpensive structure in which the curl removing roller member 14 is attached to the separation claw 12. A fixing device having stable transport performance can be obtained.

Second Embodiment FIG. 5 is a side view showing the structure of a fixing device according to a second embodiment of the present invention, FIG. 6 is a plan view taken along the line VV of FIG. 5, and FIG. FIG. 5 is a perspective view with a cutaway view, in which parts that are the same as in the first embodiment shown in FIGS. 1 to 4 are given the same reference numerals, and redundant description is omitted. In the drawing, reference numeral 18 denotes a paper discharge guide which also functions to separate the recording paper 7, and a T-shaped leg 18 a is swingably supported by the case side plates 1 a and 1 b by a shaft 19 and faces the pressure roller 9. Separation claw 1 at the tip
The separation claw 18b is pressed against the surface of the pressure roller by the rotating force applied to the paper discharge guide 18 by the elastic force of the torsion coil springs 21 and 22.

Reference numeral 23 denotes a curl removing roller member which is provided slightly behind the separation claw 18b and is provided in a notch 18c on the upper surface of the paper discharge guide 18 so that a part of the peripheral surface protrudes from the paper discharge guide surface. The thin film 2 abuts on the discharge side curved surface portion 6 a of the stay 6 via the film 2, and rotates in accordance with the movement of the thin film 2 in the direction of the arrow.

Next, the operation will be described.

When an image forming apparatus (not shown) to which the fixing device having the above-described configuration is applied is operated, the pressure roller 9 rotates in the direction of the arrow, and the thin film 2 is driven by the frictional driving force of the pressure roller 9. Move in the direction. The temperature of the heating element 5 is increased by the heating of the resistance heating element 52 over the entire length thereof by supplying power to the power supply electrodes 53 at both longitudinal ends of the resistance heating element 52, and the temperature increase is detected by the temperature measuring element 55. You. A / D conversion of the output of the temperature detecting element 55
By controlling the phase and frequency of the AC voltage of the AC power supply 17 for energizing the resistance heating element 52 by the triac 6 based on the information, the energizing power to the heating element 5 is controlled to control the heating temperature. You. That is, when the temperature detected by the temperature detecting element 55 is lower than a predetermined set temperature, the heating element 5
By controlling the power supply so that the temperature of the heater 5 rises, and when the temperature is high, the temperature of the heater 5 is decreased, so that the heater 5 is controlled to a constant temperature during fixing. Thus, the heating element 5 is heated by the heating material 5 when passing through the nip 10 in a state where the temperature of the heating element 5 rises to a predetermined value and the rotation peripheral speed of the thin film 2 due to the rotation of the pressure roller 5 is stabilized.

In this state, the recording paper 7 conveyed from the transfer section of the image forming apparatus along the entrance guide 8 is pressed against the heating element 5 via the thin film 2 by the pressure roller 9 when passing through the nip section 10. Then, the visible image on the surface heated by the heating element 5 is fixed by heating. When the recording paper 7 passes through the nip portion 10, curl is applied to the pressure roller 9 side, in the illustrated example, downward, but immediately thereafter, that is, before the recording paper 2 is almost cooled, Is pressed by the curl removing roller member 23 by the curl removing roller member 23 through the thin film film that moves to the upper side, and is moved upward by the movement of the thin film film and the rotation by the roller member 23 that is driven and rotated by the thin film film. Curl. As a result, the curl in the downward direction imparted when passing through the nip portion 10 is effectively canceled.

As described above, according to the first embodiment, with a simple and inexpensive configuration in which the curl removing roller member 23 is mounted on the separation claw 18b, the recording paper transporting performance is stable and the recording paper is separated from the paper discharge guide 18. Since the claws 18b are formed of the same member, a fixing device having a simpler configuration than that of the first embodiment can be obtained.

Third Embodiment In the first and second embodiments, an endless thin film is used. However, as shown in FIG. 8, a cylindrical thin film 2a may be used. As shown in FIG. 9, the belt-like thin film 2 b sent out from the feed roller 25 may be wound by the winding roller 26 via the heating element 5.

Fourth Embodiment FIG. 10 is a schematic diagram showing a configuration of an image forming apparatus of the present invention to which the above-described fixing device is applied. In the figure, reference numeral 31 denotes a photosensitive drum having a diameter of, for example, 30 mm as an image carrier. The photosensitive drum 31 is, for example, an OPC photosensitive drum including a conductive base layer 31b such as aluminum as a charge generation layer and a photoconductive layer 31a as a charge transport layer formed on an outer peripheral surface thereof. Is rotated at a predetermined speed in the direction of arrow R1. Around the photosensitive drum 31, in order along the rotation direction,
A pre-exposure lamp 32 for removing the surface charge of the photosensitive drum by pre-exposure; a charging roller 33 having a diameter of, for example, 12 mm as a charging member for uniformly charging the surface of the photosensitive drum to a predetermined potential; A power supply device 34 for applying a voltage, an exposure device 35 for forming an electrostatic latent image on the photosensitive drum 31 in accordance with image information, and a development for attaching toner to the electrostatic latent image and visualizing it as a toner image A device 36 (in the first embodiment, a reversal developing system using negative toner is used), and a transfer roller having a diameter of, for example, 12 mm as a transfer member for transferring the toner image on the photosensitive drum 31 to transfer paper 38 as a recording material 37, a static eliminator 39 for removing the charge of the transfer paper 38 after the transfer of the toner image, and a residual toner attached to the surface of the photosensitive drum 1 after the transfer of the toner image is removed and collected. Image forming means such as a cleaner 40 is disposed. Reference numeral 41 denotes a fixing device described in any one of FIGS. 1 to 3 and FIGS. 5 to 9.

The charging roller 33 and the power supply device 34 constitute a contact charging device. The charging roller 33 has a central core 33a and a conductive rubber 33b formed on the outer surface thereof.
It is composed of Both ends of the core bar 33a are rotatably supported by a bearing member (not shown) and arranged in parallel with the photosensitive drum 31, and have a constant pressing force against the photosensitive drum 31 by a pressing member (not shown). Pressed
The photosensitive drum 31 rotates following the rotation of the photosensitive drum 31. Further, a driving force transmitting member such as a gear and a roller (not shown) is attached to an end of the core bar 33a.
It is also possible to rotate in the forward or reverse direction with respect to the rotation of.

Next, the operation at the time of image formation by the image forming apparatus configured as described above will be described. Photosensitive drum 31
Is driven to rotate at a predetermined speed in the direction of arrow R1. To the charging roller 33, for example, an oscillating voltage in which a DC voltage (a constant voltage of 625 V) is superimposed on an AC voltage (a peak-to-peak voltage Vpp = 2.0 KV, a sine wave having a frequency of 400 Hz) is applied from the power supply device 34, The surface of the drum 1 is charged to a uniform potential of 1600V.

The charged photosensitive drum 31 is exposed to an exposure unit 35.
Exposure of the target image information (slit exposure of the original image,
Laser beam scanning exposure, etc. In the illustrated example, the electrostatic latent image is formed by receiving slit exposure of a document image. Next, this electrostatic latent image is visualized with toner by the developing means 36 to become a toner image.

The transfer means 37 transfers the toner image visualized on the photosensitive drum 31 to the recording paper 38, and then the charge eliminator 39 removes the charge of the transferred recording paper 38 and sends it to the fixing means 41 of the present invention. The sheet is conveyed to fix the toner image on the recording paper 38.

On the other hand, the toner remaining on the surface of the photosensitive drum 31 after the transfer is cleaned and removed by the cleaner 40, and then the charge remaining on the photosensitive drum 31 is removed by pre-exposure by the pre-exposure lamp 32. Again for the next image formation.

[0042]

As described above, according to the present invention,
On the downstream side of the nip formed by the heating element and the pressure roller via the thin film, by a roller member that abuts on the thin film and is driven to rotate by the running of the thin film, the recording paper sent from the nip is applied to the recording paper. Since the curl is applied in a direction opposite to that of the pressure roller, the curl applied to the recording paper during fixing can be efficiently reduced with a simple structure. As a result, it is possible to prevent the recording paper from jamming in the transport path downstream of the fixing device, and to obtain a fixing device having stable recording paper transportability.

Further, since the roller member is provided on the separation claw rotatably mounted on the paper discharge guide or on the separation claw formed integrally with the paper discharge guide, a special mounting member is not required and the structure is further simplified. There is an effect that can be converted.

Further, since the fixing device of the present invention is applied, there is an effect that an image forming apparatus in which recording paper is smoothly transported can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a fixing device according to a first embodiment.

FIG. 2 is a plan view taken along the line II of FIG.

FIG. 3 is a perspective view partially cut away.

FIG. 4 (a) is a schematic plan view of a heating element with a partly omitted partly cutaway view, and FIG. 4 (b) is a cross-sectional schematic view.

FIG. 5 is a side view showing a fixing device according to a second embodiment.

FIG. 6 is a plan view along the line VV in FIG. 1;

FIG. 7 is a perspective view partially cut away.

FIG. 8 is a schematic diagram showing a modification of the thin film according to the third embodiment.

FIG. 9 is a schematic view showing a modification of the thin film according to the third embodiment.

FIG. 10 is a side view illustrating an image forming apparatus according to a fourth embodiment.

FIG. 11 is a side view showing a conventional fixing device.

[Description of Signs] 2 Thin film film, 5 Heating body, 7, 38 Recording paper (Recording body), 10 Nip section, 11 Discharge guide, 12 Separation claw.

Claims (6)

[Claims] 1. A fixing device comprising: a heating element for heating a recording medium via a thin film; and a pressing roller for pressing the recording element against the heating element via the thin film, On the downstream side of the nip formed by the heating element and the pressure roller, the pressure roller abuts against the thin film and is driven to rotate by the running of the thin film, and the recording medium sent out from the nip is pressed by the pressure roller. And a roller member for imparting curl in a direction opposite to that of the fixing device. A discharge guide disposed downstream of the nip portion; and a separation claw urged to abut on a pressure roller at a leading end thereof and rotatably provided on the discharge guide. A roller member is provided on the separation claw that abuts against the thin film and is driven to rotate by the running of the thin film and imparts curl to the recording medium sent from the nip in a direction opposite to that of the pressure roller. The fixing device according to claim 1, wherein: 3. A thin film film, wherein a discharge guide and a separation claw are integrally provided, and a tip of the separation claw is urged so as to abut against a pressure roller to rotatably attach the discharge guide to a case side plate. The separation claw is provided with a roller member that abuts on the recording medium and that is driven to rotate by the running of the thin film and imparts curl to the recording medium sent from the nip in a direction opposite to that in the case of the pressure roller. The fixing device according to claim 1. 4. The fixing device according to claim 1, wherein the thin film is a heat-resistant film. 5. The fixing device according to claim 4, wherein the film thickness of the heat-resistant film is 100 μm or less. 6. The image forming means, and the recording medium sent from the image forming means is heated to fix a visible image formed on the recording medium. An image forming apparatus comprising: the fixing device according to claim 1.