JP2000089603A - Peeling device and fixing device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent trouble in image quality caused by the contact of an image supporting body to which a toner image is transferred with a peeling member peeling the image supporting body from a fixing member by forcibly forming an air layer between the peeling member and the image supporting body. SOLUTION: This fixing device 33 is provided with plate-like peeling members 54 and 55 peeling transfer paper from a heating roll 33a and a pressure roll 33b near the exit of a press-contact part 53 between the rolls 33a and 33b. The members 54 and 55 are formed to have wedged cross sections and arranged in a non-contact state so that the tips thereof may form a small gap on the surfaces of the rolls 33a and 33b. The upper member 54 is constituted so as to jet air from an aperture part formed on its lower surface. The other member 55 is constituted so as to suck the air from an aperture part formed on its lower surface. Thus, the air layer is forcibly formed between the members 54 and 55 and transfer paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus to which an electrophotographic method is applied, such as an electrophotographic copying machine or a printer, and a peeling device used in the fixing device. The present invention relates to a peeling device capable of reliably preventing an image quality failure due to contact between an image support onto which an image has been transferred and a peeling member, and a fixing device using the same.

[0002]

2. Description of the Related Art Conventionally, as a fixing device used in an image forming apparatus to which an electrophotographic system such as an electrophotographic copying machine or a printer is applied, for example, a heating roll having a heating source therein and a pressure roll are provided. Are brought into pressure contact with each other, and a transfer sheet (image support) on which the unfixed toner image is transferred is conveyed to a pressure contact portion (nip portion) between the heating roll and the pressure roll,
While passing through the nip between the two rolls, the unfixed toner image is fixed on the transfer paper by heat and pressure.

In such a fixing device, the transfer sheet on which the unfixed toner image has been transferred is passed through a nip between the two rolls, and the unfixed toner image is fixed on the transfer sheet by heat and pressure. Further, there is a fear that the transfer sheet is wrapped around the surface of the heating roll due to the adhesive action of the toner that has been melted by heating, so that the fixing device cannot be used.

Therefore, in the fixing device configured as described above, many techniques have been already proposed and already implemented in order to surely remove the transfer paper from the surface of the heating roll. Among them, as a device relating to a peeling device of an image forming apparatus, for example, as disclosed in Japanese Utility Model Application Laid-Open No. 62-127564, a portion for discharging transfer paper from a nip portion between a heating roller and a pressure roller, A configuration in which peeling means for forcibly peeling the transfer paper from the surface of the heating roller is arranged to prevent the transfer paper from being rotated while being adhered to the surface of the heating roller has been proposed by the present applicant. Have been.

[0005]

However, the prior art described above has the following problems. That is, in the peeling device as disclosed in Japanese Utility Model Application Laid-Open No. 62-127564, the transfer paper is forcibly applied from the surface of the heating roller to the portion where the transfer paper is discharged from the nip between the heating roller and the pressure roller. A peeling means is provided to prevent the transfer paper from being rotated while adhering to the surface of the heating roller.However, in the case of such a peeling device, the transfer paper is fixed by a peeling member. When the paper is peeled from the roll, a part of the peeling member comes into contact with the toner image immediately after being fixed on the transfer paper due to rubbing between the peeling member and the paper, and the uncured toner image immediately after being fixed. And there is a problem that image quality may be disturbed.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide an image quality by contact between an image support on which a toner image has been transferred and a peeling member. An object of the present invention is to provide a peeling device capable of reliably preventing a failure and a fixing device using the same.

[0007]

According to a first aspect of the present invention, there is provided a peeling device for peeling an image support on which a toner image is fixed from a pair of fixing members at least one of which is a roll. A release member for separating the image support from the fixing member formed of a roll near the outlet of the pressure contact portion of the fixing member, and an air layer forcibly forming an air layer between the release member and the image support. It is configured to provide forming means.

According to a second aspect of the present invention, the image support having the toner image transferred thereon is conveyed while being sandwiched between a pair of fixing members at least one of which is a roll, so that the toner is transferred onto the image support. In the fixing device for fixing an image, near the outlet of the pressure contact portion of the pair of fixing members, a peeling member for peeling the image support from the fixing member formed of a roll, and between the peeling member and the image support A fixing device is provided with air layer forming means for forcibly forming an air layer.

Further, according to a third aspect of the present invention, the air layer forming means comprises means for jetting air from a surface of the peeling member on the image support side.
It is a fixing device described in Item.

According to a fourth aspect of the present invention, the air layer forming means determines the amount of air ejected from the surface of the peeling member on the image support side by a passing speed of the image support and a size of the image support. 4. The fixing device according to claim 3, wherein the control is performed based on at least one of a type of the image support and an amount of the toner carried on the image support.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings.

FIG. 2 shows a digital copying machine as an image forming apparatus to which the fixing device according to the present invention is applied.

In FIG. 2, reference numeral 1 denotes a main body of a digital copying machine. An automatic document feeder for automatically feeding originals 2 separated one by one is provided above the digital copying machine main body 1. An (ADF) 3 and an image reading device 4 for reading an image of the document 2 conveyed by the automatic document conveying device 3 are provided. The image reading device 4 illuminates a document 2 placed on a platen glass 5 with a light source 6, and reflects a reflected light image from the document 2 on a full-rate mirror 7.
And an image reading element 11 such as a CCD through a reduction optical system including half rate mirrors 8 and 9 and a lens 10.
It is configured to scan and expose on top.

The image information of the document 2 read by the image reading device 4 is stored in a temporary storage device (not shown), and an IPS (Image Process) as needed.
After a predetermined image processing is performed by the ing system 12, a ROS (Raster Output Scanner) is performed according to the image information on which the image processing is performed.
r) 13, the photosensitive drum 14 as an image carrier
Image exposure is performed thereon to form an electrostatic latent image. R above
The OS 13 includes a semiconductor laser 15 that emits a laser beam according to image information, and a polygon mirror 1 that scans a laser beam emitted from the semiconductor laser 15.
6 and mirrors 17 and 18 for exposing the laser beam scanned by the polygon mirror 16 onto the photosensitive drum 14. Prior to image exposure by the ROS 13, the photosensitive drum 14 is uniformly charged to a predetermined potential of a predetermined polarity by a primary charger 19 made of a scorotron.
The image of the document 2 is exposed by the OS 13 to form an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 14 is developed by a developing device 20 as a developing unit to become a toner image. This toner image is transferred to the transfer charger 21
Is transferred onto the transfer paper 22 by the charging of
The transfer paper 22 to which the toner image has been transferred is separated from the photosensitive drum 14 by the charge removal of the separation charger 23.
The transfer paper 22 to which the toner image is transferred from the photosensitive drum 14 is supplied by a paper feed roll 28 from one of a plurality of paper feed cassettes 24, 25, 26, and 27 provided inside the copying machine body 1. The paper is transported to the registration gate 31 via the transport roll 29 and the pre-registration roll 30 and stopped once. Then, the transfer paper 22 passes through a registration gate 31 that opens in synchronization with the toner image formed on the surface of the photosensitive drum 14, and is transferred by a registration roll 32 disposed downstream of the registration gate 31. After being transported to the surface of the photosensitive drum 14 and the toner image formed on the surface of the photosensitive drum 14 is transferred as described above, the toner image is peeled off from the surface of the photosensitive drum 14.

The transfer paper 22 separated from the surface of the photosensitive drum 14 is transported to a fixing device 33 by a transfer material transport device transport device 50, and the toner is transferred onto the transfer paper 22 by heat and pressure by the fixing device 33. The image is fixed. The transfer paper 22 on which the toner image is fixed is discharged by an outlet roll 34 of a fixing device 33 onto a discharge tray 36 outside the apparatus by a discharge roll 35 as it is in the case of normal single-sided copying. In the case of double-sided copying, the transfer sheet 22 having the toner image fixed on one side thereof is not discharged to the outside of the apparatus by the discharge roll 35, but the transport direction is changed downward by the reversing gate 37, and the three rolls are transferred. Is once conveyed to the reversing passage 40 by the tri-roll 38 and the reversing roll 39 pressed against each other. Then, the transfer paper 22 is conveyed to the two-sided passage 42 by the reversing roll 39 and the two-sided roll 41 which are reversed this time, and is once conveyed from the two-sided passage 42 to the registration gate 31 via the pre-registration roll 30. Stop, and as described above, the resist gate 31 and the resist roll 3
2, the toner image is conveyed in synchronism with the toner image on the photosensitive drum 14, and is transferred onto a discharge tray 36 by a discharge roll 35 after the toner image is transferred and fixed.

After the toner image transfer step is completed, the surface of the photosensitive drum 14 is cleaned of residual toner, paper dust and the like by the cleaning device 43 to prepare for the next image forming step.

FIG. 3 is an enlarged view of the image forming section of the digital copying machine constructed as described above.

In FIG. 3, reference numeral 14 denotes the above-mentioned photoconductor drum. As the photoconductor drum 14, for example, a photoconductor using an organic photoconductive substance is used.
The photosensitive drum 14 is driven at a predetermined rotational speed along a direction indicated by an arrow A by a driving unit (not shown). The surface of the photosensitive drum 14 is uniformly charged to a predetermined potential by a primary charger 19 made of a scorotron or the like. Thereafter, on the surface of the photosensitive drum 14, the laser light LB is scanned and exposed according to the image information by the ROS 13 that performs image exposure based on the image information, and an electrostatic latent image is formed. The electrostatic latent image formed on the photosensitive drum 14 is
a to form a toner image. Further, the toner image formed on the surface of the photoconductor drum 14 is charged by the transfer auxiliary charger 44 and is auxiliary-charged.
29 and the resist roll 32, the photosensitive drum 1
Transfer paper 2 conveyed at a predetermined timing to the surface of
2 is transferred by the charging of the transfer charger 21. The transfer paper 22 to which the toner image has been transferred as described above is neutralized by a peeling charger 23, peeled off from the surface of the photosensitive drum 14, and is conveyed to the fixing device 33 by the conveying belt 51 of the paper conveying device 50. The toner image is fixed on the transfer paper 22 by heat and pressure by the heating roll 33a and the pressure roll 33b of the fixing device 33, and is discharged onto a discharge tray 36 provided outside the device. The cleaning device 43 removes residual toner and the like from the surface of the photosensitive drum 14 on which the transfer of the toner image has been completed, so that the surface is ready for the next image forming process. In the drawing, reference numeral 45 denotes a housing of the cleaning device, 46 denotes a cleaning brush, 47 denotes a cleaning blade, 48 denotes a film seal, and 49 denotes a collected toner conveying means.

FIG. 4 is a structural view showing the fixing device.

This fixing device 33 is, as shown in FIG.
It has a heating roller 33a having a heating source 52 inside, and a pressure roller 33b arranged to be in pressure contact with the heating roller 33a. The heating roller 33a and the pressure roller 33b are pressed against each other with a predetermined pressure,
The transfer paper 22 as an image support on which the toner image has been transferred from the surface of the photosensitive drum 14 is transported to the nip 53 between the rollers 33a and 33b.

The transfer paper 22 carrying the unfixed toner image is melted by heat and pressure while passing through the nip 53 between the heating roller 33a and the pressure roller 33b. Then, the toner image is fixed on the transfer paper 22 to become a permanent image.

In this embodiment, a peeling member for peeling off the image support from the fixing member formed of a roll is provided near the exit of the pressure contact portion of the pair of fixing members. An air layer forming means for forcibly forming an air layer is provided between them.

That is, in the fixing device 33 according to this embodiment, as shown in FIG. 1, the heating roll 3a is located near the exit of the pressure contact portion 53 between the heating roll 33a and the pressure roll 33b.
Plate-like peeling members 54 and 55 for peeling the transfer paper 22 from the 3a and the pressure roll 33b are provided, and the transfer paper 22 is separated from the surfaces of the heating roll 33a and the pressure roll 33b by the peeling members 54 and 55. It is configured to forcibly peel off.

The peeling members 54 and 55 are shown in FIGS.
As shown in (1), it is formed in a wedge-shaped cross section, and its tip is arranged in a non-contact state so as to form a slight gap on the surfaces of the heating roll 33a and the pressure roll 33b. The upper peeling member 54 is configured to blow air from an opening 56 provided on the lower surface 54a, and the other peeling member 55 is
Air is formed through an opening 57 provided in the transfer sheet 22. Air layer forming means for forcibly forming an air layer between the peeling members 54 and 55 and the transfer sheet 22 is formed. It also has the function of

In the embodiment shown in FIG. 1 and FIG. 5, in addition to the heating roll 33a,
A case has been described in which the peeling member 55 is provided and the air is sucked from the peeling member 55. However, the present invention is not limited to this, and the peeling member 54 is provided only on the heating roll 33a side. Is also good.

The peeling members 54 and 55 have the same structure. For example, as shown in FIG. 6, the peeling member 54 has a circular opening 56 having a predetermined diameter on a lower surface 54a thereof at a predetermined interval. And these openings 5
Numerals 6 are formed inside the peeling member 54 and connected to each other through a communication path 58. In addition, the peeling member 54,
The openings 56 and 57 provided in the 55 are formed in, for example, a circular shape as shown in FIG. 7A, but are not limited thereto, and may be elliptical as shown in FIG. 7B. It may be formed in a shape or a rectangular shape.

Further, as shown in FIG. 1, the plurality of openings 56 provided in the peeling member 54 are connected to a flow meter 60 through a communication passage 58 and an air pipe 59. Is connected to the compressor 61. Further, the plurality of openings 57 provided in the other peeling member 55 are connected to the suction fan 63 via the communication passage 58 and the air pipe 62 as shown in FIG.

FIG. 8 is a block diagram showing a control circuit of the fixing device according to this embodiment.

In FIG. 8, reference numeral 64 denotes a CPU for controlling the copying operation of the fixing device. The CPU 64 transfers an image forming signal, information on the conveying speed and width of the transfer sheet 22, and further transfers the image on the transfer sheet 22. For example, information indicating the amount of waste toner is input. The CPU 64 controls the image writing timing signal, the transport speed and width information of the transfer sheet 22, the type of the transfer sheet 22, the information indicating the amount of toner transferred onto the transfer sheet 22, and the like. From the compressor 61
And the amount of air sucked by the fan 63 is controlled.

In the fixing device provided with the peeling device according to the present embodiment, the occurrence of image quality failure due to the contact between the image support on which the toner image has been transferred and the peeling member is as follows. It surely prevents it.

That is, in a digital copying machine to which the fixing device according to this embodiment is applied, as shown in FIG.
At a predetermined timing, a toner image corresponding to the image of the original 2 is formed on the photosensitive drum 14, the toner image is transferred onto a transfer sheet 22, and the transfer sheet 22 on which the toner image is transferred is fixed to a fixing device. To the fixing device 3
3, the toner image is fixed on the transfer paper 22 by heat and pressure, and the image of the original 2 is copied.

In the fixing device 33, as shown in FIG. 3 and FIG.
Prior to the transfer paper 22 carrying the unfixed toner image passing through the nip portion between 3b and 3b, as shown in FIGS. 9 and 10, the CPU 64 detects the image forming signal and simultaneously Spouting of air from the opening 56 for blowing air. And / or start air suction from the air suction opening 57 of the peeling member 55 (steps 102 and 2).
02). In the fixing device 33, FIGS.
As shown in (1), an air layer is formed between the peeling member 54 and the image surface of the transfer sheet 22 by the air jetted from the opening 56 of the peeling member 54, and / or the back side of the image surface is sucked. By forming an air layer between the peeling member 55 and the image surface of the transfer paper 22 by air sucked from the opening 57 of the peeling member 55, the transfer paper 22
4 and 55, the transfer sheet 22 and the release member 5
The frictional resistance between the transfer member 22 and the transfer member 55 can be reduced, and the toner image can be reliably prevented from being disturbed by the contact of the peeling member 54 with the toner image on the transfer paper 22. Further, the air ejected from the peeling member 54 causes the transfer paper 2
2. the uncured toner image on 2 can be curably cooled;
Also from this point, it is possible to reliably prevent the toner image from being disturbed.

At this time, the amount of air blown out from the opening 56 of the peeling member 54 is determined by the value of the step 10 in FIGS.
At 1, 201, for example, it is determined as follows.

Now, the transfer paper 22 in the fixing device 33
Is PS (mm / s), the thickness of the air layer to be formed is d (mm), the paper passing width of the transfer paper 22 is L (mm),
Assuming that the volume VO (mm ³ ) of the formed air layer, the diameter of the opening of the peeling member is D (mm), the number of the openings is N, and the ejection speed of air is v (mm / s), the following relationship is obtained. Holds. PS × d × L = VO VO = v × D 2/4 × π × N

Here, for example, PS = 160, d = 0.
When 2, L = 278 and v = 2000, the diameter of the opening 56 having a circular cross section is φ0.7 mm, and 12 openings are required.

The shape of the peeling member 54 is as follows.
As shown in FIG. 6, the present invention is not limited to a flat plate.
12 or a comb shape as shown in FIG.
You may use the thing of the peeling nail shape isolate | separated one by one.

[0037]

As described above, according to the present invention, a peeling device and a fixing device using the same can surely prevent the occurrence of image quality failure due to the contact between the peeling member and the image support on which the toner image has been transferred. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a fixing device to which a peeling device according to an embodiment of the present invention is applied.

FIG. 2 is a configuration diagram showing a digital copying machine to which the fixing device according to the present invention can be applied.

FIG. 3 is a configuration diagram illustrating an image forming unit of FIG. 2;

FIG. 4 is a configuration diagram showing a fixing device according to an embodiment of the present invention.

FIG. 5 is a configuration diagram illustrating a main part of a fixing device to which the peeling device according to the embodiment of the present invention is applied;

FIG. 6 is a partial plan view showing a peeling member.

FIGS. 7A and 7B are partial plan views showing the shape of the opening of the peeling member.

FIG. 8 is a block diagram showing a control circuit of the fixing device according to one embodiment of the present invention.

FIG. 9 is a flowchart showing an operation of the fixing device according to the embodiment of the present invention.

FIG. 10 is a flowchart showing an operation of the fixing device according to the embodiment of the present invention.

FIG. 11 is a configuration diagram showing another embodiment of the peeling device.

FIG. 12 is a configuration diagram showing still another embodiment of the peeling device.

[Explanation of symbols]

22: transfer paper (image support), 33: fixing device, 33
a: Heating roll, 33b: Pressure roll, 54, 55: Peeling member, 56, 57: Opening, 61: Compressor.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideaki Sekiguchi 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Masaru Kijima 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Haruhiko Sano 2274 Hongo, Ebina-shi, Kanagawa Prefecture F-term in Fuji Xerox Co., Ltd. (Reference) 2H033 AA10 AA25 BA15 BA20 BA22 CA16 CA17 CA22 CA26 3F053 AA04

Claims (4)

[Claims] 1. A peeling device for peeling an image support on which a toner image has been fixed from a pair of fixing members, at least one of which is formed of a roll, comprising: A peeling device comprising: a peeling member for peeling an image support from a member; and an air layer forming means for forcibly forming an air layer between the peeling member and the image support. 2. A fixing device for fixing a toner image on an image support by conveying the image support on which a toner image has been transferred while nipping the image support between at least one of a pair of fixing members comprising a roll, Near the outlet of the pressure contact portion of the pair of fixing members, a release member for separating the image support from the fixing member formed of a roll is provided, and air forcibly forming an air layer between the release member and the image support is provided. A fixing device comprising a layer forming unit. 3. The fixing device according to claim 2, wherein said air layer forming means comprises means for jetting air from a surface of said peeling member on an image support side. 4. The image forming apparatus according to claim 1, wherein the air layer forming means determines the amount of air ejected from the surface of the peeling member on the image support side, the passing speed of the image support, the size of the image support, the type of the image support, and the image support. 4. The control according to claim 3, wherein the control is performed based on at least one of an amount of the toner carried on the body.
The fixing device according to the item.