JP2002357968A - Fixing device and image forming device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device by which the sticking of oil to a recording medium and the soiling of the inside of a device due to the leakage of the oil from the end part of a fixing belt are prevented without causing the complication of the constitution of the device and the increase of the cost and an image forming device using it. SOLUTION: In this fixing device which is provided with a heating member and a pressing member which are disposed so as to come into press-contact with each other and at least either of which is constituted of a belt-shaped member, a belt guide member freely rotatably supporting both end parts of the belt-shaped member out of the heating member and the pressing member, a press-contact member disposed at the inside of the belt-shaped member and to bring the belt-shaped member into press-contact with the surface of the other member and an oil supply member to supply the inner surface of the belt-shaped member with the oil and by which fixing is performed by passing the recording medium carrying an unfixed toner image through a nip part formed between the heating member and the pressing member, an oil leakage prevention means to prevent the leakage of the oil is provided at least either of the outer peripheral surface of the belt guide member and the inner peripheral surface of the belt-shaped member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic system,
A fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., which adopts an image forming method such as an electrostatic recording method, an ionography, and a magnetic recording method, and forms a color or black and white image. Regarding the image forming apparatus, in particular, in a fixing device using an endless belt as a pressing member or a heating member, even when the inner surface of the endless belt is configured to apply oil, even if the oil is applied to the inner surface of the endless belt, the end of the endless belt is The present invention relates to a fixing device capable of reliably preventing oil from leaking, and an image forming apparatus using the fixing device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer or a facsimile which employs an image forming method such as the above-mentioned electrophotographic method, not only the image quality such as full color and high image quality are required. Satisfies various demands such as miniaturization of equipment, long life, high productivity, power saving, and reduction of first printout time (time from power-on until printing of the first sheet becomes possible). Is being sought.

The present applicant has proposed various image forming apparatuses to meet the needs of such image forming apparatuses such as copiers and printers.
As disclosed in Japanese Patent Application Laid-Open No. 0-78686, an image forming apparatus capable of reducing the size of an apparatus and forming a high-quality color image without using a complicated image misalignment prevention technique. The device has already been proposed.

The image forming apparatus disclosed in Japanese Patent Application Laid-Open No. H10-78686 includes various embodiments. One of the embodiments is an image forming apparatus including two photosensitive members and one intermediate transfer member. , And a unit structure composed of the other two photosensitive members and one intermediate transfer member, and one of the two intermediate transfer members further includes one more intermediate transfer member.
A structure in which two intermediate transfer members are in contact with each other has been proposed. The four photoconductors shown here have a common tangent line, and therefore, a charging device, an exposing device, a developing device, and a cleaning device disposed around these four photoconductors have respective photoconductors. Are arranged at the same position, and devices are shared for each device type.

In this image forming apparatus, each toner image formed on the two photosensitive members is transferred to an intermediate transfer member and then to a third intermediate transfer member, and is transferred to the other two photosensitive members. Each of the formed toner images is transferred to the other intermediate transfer member, and then transferred to the third intermediate transfer member. The toner images transferred to the third intermediate transfer member are collectively transferred onto the recording paper that has been conveyed. Is transcribed. The toner image transferred onto the paper P is fixed on the recording paper by a fixing device. Since the intermediate transfer body is a drum type and is made of a rigid body, a misalignment between toner images hardly occurs.

By the way, the fixing device used in this type of so-called tandem type image forming apparatus has a power saving and a first printout time (the time from when the power is turned on until the first sheet can be printed). It is required to meet the demands such as shortening of time.

As a fixing device that meets such demands, an endless belt-shaped fixing belt is pressed against a heating roll having a heating source inside by a pressing member disposed inside the fixing belt. There is a configuration in which a fixing process is performed by heat and pressure by passing a recording medium carrying an unfixed toner image through a nip portion formed between the heating roll and the fixing belt.

In this fixing device, a fixing belt in which a pressing member is formed in an endless belt shape instead of a roll-shaped member,
Since the fixing belt includes a pressing member for pressing the fixing belt against the heating roll, the heat capacity of the pressing member can be reduced, the thickness of the heating roll can be reduced, and the heating roll is heated to a predetermined fixing temperature. Power consumption and time can be reduced, and it is possible to achieve power saving and a reduction in the first printout time (the time from when the power is turned on until the first print can be performed). It becomes possible.

By the way, in the fixing device, the fixing belt is pressed against the heating roll by the pressing member, so that if the friction between the fixing belt and the pressing member is large, the running of the fixing belt is hindered. This may cause poor fixing and paper wrinkles.

Therefore, in the fixing device configured as described above, by supplying oil to the inner surface of the fixing belt, friction generated between the fixing belt and the pressure contact member is reduced, and the smooth running of the fixing belt is achieved. It is configured to allow it.

[0011]

However, the prior art described above has the following problems. That is, in the case of the fixing device used in the above-described conventional image forming apparatus, the friction generated between the fixing belt and the pressing member is reduced, and the smooth running of the fixing belt is enabled. It is configured to supply oil to. Therefore, in the fixing device, while the fixing process is repeated, the oil gradually moves to the end of the fixing roll, leaks from the end of the fixing roll, adheres to the recording paper, or stains the inside of the device. There was a problem.

In order to solve this problem, it is conceivable to finely control the amount of oil supplied to the inner surface of the fixing belt. However, in this case, the configuration of the apparatus becomes complicated,
There is a new problem that increases the cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a fixing device without complicating the structure of the apparatus or increasing the cost. An object of the present invention is to provide a fixing device and an image forming apparatus using the fixing device, which can prevent oil from leaking from an end portion of a belt and adhere to a recording medium or stain the inside of the apparatus.

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 is provided so as to be in pressure contact with each other, at least one of which comprises a heating member comprising a belt-like member and a pressure member. A member, a belt guide member rotatably supporting both ends of a belt-shaped member of the heating member and the pressure member, and the belt-shaped member disposed inside the belt-shaped member. An unfixed toner is provided in a nip portion formed between the heating member and the pressing member, comprising: a pressing member for pressing against the surface of the other member; and an oil supply member for supplying oil to the inner surface of the belt-shaped member. In a fixing device for performing fixing by passing a recording medium carrying an image, an oil for preventing oil from leaking to at least one of an outer peripheral surface of the belt guide member and an inner peripheral surface of the belt-shaped member. A fixing device which is characterized in that a leakage preventing means.

As the above-mentioned heating member, for example, a heating roll having a heating source inside is used, and as the pressing member, a belt-shaped fixing belt is used. The pressing member may be a roll-shaped member, or both the heating member and the pressing member may be belt-shaped members.

According to a second aspect of the present invention, the oil leakage preventing means comprises at least one groove provided on an outer peripheral surface of the belt guide member. It is a fixing device of the above.

Further, the invention described in claim 3 is characterized in that the oil leakage preventing means comprises a groove provided on the outer peripheral surface of the belt guide member so as to be inclined toward the inside of the belt-shaped member. The fixing device according to claim 1, wherein:

Still further, according to the invention described in claim 4,
2. The fixing device according to claim 1, wherein the oil leakage prevention unit includes a seal member attached to an outer peripheral surface of the belt guide member. 3.

Further, the invention described in claim 5 is characterized in that the oil leakage preventing means comprises a streaky projection provided on the inner peripheral surface of the belt-shaped member. It is a fixing device of the above.

According to a sixth aspect of the present invention, in the fixing device according to the first aspect, the oil leakage preventing means comprises a groove provided on an outer peripheral surface of the belt guide member. is there.

According to a seventh aspect of the present invention, the toner images of different colors formed on a plurality of image carriers are transferred onto a recording medium via a plurality of intermediate transfer members and then pressed against each other. A heating member and a pressure member, at least one of which is a belt-shaped member, and rotatably support both ends of a belt-shaped member of the heating member and the pressure member. A belt guide member, a pressure contact member disposed inside the belt-shaped member for pressing the belt-shaped member against the surface of the other member, and an oil supply member for supplying oil to the inner surface of the belt-shaped member. An image forming apparatus for forming an image by passing a recording medium carrying an unfixed toner image through a fixing device and fixing the recording medium carrying an unfixed toner image to a nip formed between the heating member and the pressing member, The image forming apparatus is characterized in that at least one of the outer peripheral surface of the belt guide member and the inner peripheral surface of the belt-shaped member is provided with an oil leakage preventing unit for preventing oil leakage. .

As the plurality of image carriers, for example, those which form toner images of cyan (C), magenta (M), yellow (Y), and black (K) are used. The order and type of the colors may be other.

[0023]

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

Embodiment 1 FIG. 2 shows a tandem-type full-color printer as an image forming apparatus using an image forming apparatus to which a fixing device according to Embodiment 1 of the present invention is applied.

In FIG. 2, reference numeral 01 denotes a main body of a tandem type full-color printer.
The inside of 01 is roughly divided into a print head device (Print Head Device) 02 for performing full-color image formation,
An ROS (Raster Output Scanner) 03 as an exposure device for exposing four photosensitive drums 11, 12, 13, and 14 as image carriers of the print head device 02, and developing each color of the print head device 02. Equipment 41, 42,
Four toner boxes 04Y, 04M, 04C, and 04K for supplying toners of colors corresponding to 43 and 44; a paper cassette 05 for supplying recording paper P as a recording medium to the print head device 02; A fixing device 70 that performs a fixing process on the recording paper P on which the toner image has been transferred from the device 02, and a recording paper P on which an image is fixed on one side by the fixing device 70 are again turned upside down. A double-sided conveyance path 07 for conveying to the transfer unit of the print head device 02, a manual paper feeding unit 08 for feeding desired recording paper P from outside the printer main body 01, and a controller 09 for controlling the operation of the printer; An electric circuit 10 including an image processing circuit for performing image processing on an image signal and a high-voltage power supply circuit is provided. In FIG. 2, T indicates a discharge toilet that discharges the recording paper P on which an image is formed, and the discharge toilet T is integrally disposed on the upper portion of the printer main body 01.

Of the various members provided inside the printer main body 01, ROS03 as an exposure device corresponds to each color of yellow (Y), magenta (M), cyan (C), and black (K). F-θ lens or polygon mirror for deflecting and scanning four semiconductor lasers driven to be lit based on the obtained image data, four laser lights emitted from these four semiconductor lasers, or a plurality of reflections It is composed of a mirror and the like.

FIG. 3 shows a print head device of a tandem type full color printer as an image forming apparatus according to Embodiment 1 of the present invention. In addition, the arrow in FIG. 3 has shown the rotation direction of each rotating member.

As shown in FIG. 3, the print head device 02 includes photosensitive drums (image carriers) 11, 12 for yellow (Y), magenta (M), cyan (C), and black (K). Forming units 1, 2, 3, including
4 and a primary charging charging roller (contact type charging device) 21, 22, 23, 2 for contacting the photosensitive drums 11, 12, 13, 14.
4 and laser beams 31, 32, 33, and 33 of yellow (Y), magenta (M), cyan (C), and black (K), respectively.
An ROS (exposure device) 03 (see FIG. 2) for irradiating the photosensitive drums 34, 34, and the electrostatic latent images formed on the photosensitive drums 11, 12, 13, and 14 are converted into yellow (Y), magenta (M), and cyan. (C),
A developing device 41 for developing with each color toner of black (K),
42, 43, 44 and the above four photosensitive drums 11, 12, 13, 14
The first primary intermediate transfer drum (intermediate transfer member) 51 that contacts two of the photosensitive drums 11 and 12 and the second primary intermediate transfer drum (intermediate) that contacts the other two photosensitive drums 13 and 14 Transfer member) 52, a secondary intermediate transfer drum (intermediate transfer member) 53 that contacts the first and second primary intermediate transfer drums 51 and 52, and a final transfer roll (contact member) that contacts the secondary intermediate transfer drum 53. The main part thereof is constituted by the transfer member 60.

The photosensitive drums 11, 12, 13, and 14 are arranged at regular intervals so as to have a common tangent plane M. The first primary intermediate transfer drum 51 and the second primary intermediate transfer drum 52 have respective rotating shafts corresponding to the photosensitive drums 11 and 1.
They are arranged so as to be parallel to the axes 2, 13, 14 and have a plane symmetry with a predetermined plane of symmetry as a boundary. Further, the secondary intermediate transfer drum 53 includes the photosensitive drums 11, 12, 13, 14
And the rotation axis are parallel to each other.

A signal corresponding to the image information of each color is rasterized by an image processing circuit provided in the electric circuit 10 (see FIG. 2) and is input to the ROS03. This ROS
In 03, laser beams 31, 32, 33, and 33 of each color of yellow (Y), magenta (M), cyan (C), and black (K) are shown.
34 is modulated, and the photoconductor drums 11, 12, 13,
Irradiated at 14.

Around the photosensitive drums 11, 12, 13, and 14, an image forming process for each color is performed by a known electrophotographic method. First, the photosensitive drums 11, 12, 1
As the photoconductors 3 and 14, for example, photoconductor drums using an OPC photoconductor having a diameter of 20 mm are used, and the photoconductor drums 11, 12, 13, and 14 are driven to rotate at a rotation speed of, for example, 95 mm / sec. You. The photosensitive drums 11, 12, 13, 14
As shown in FIG. 3, the surface of is charged to about -300 V, for example, by applying a DC voltage of about -840 V to the charging rolls 21, 22, 23, and 24 as contact-type charging devices. The contact-type charging device includes a roll-type charging device, a film-type charging device, and a brush-type charging device, but any type may be used.
In this embodiment, a charging roll generally used in an electrophotographic apparatus in recent years is employed. Further, in this embodiment, in order to charge the surfaces of the photoconductor drums 11, 12, 13, and 14, a charging method of applying only DC is used, but a charging method of applying AC + DC may be used.

Thereafter, the surfaces of the photosensitive drums 11, 12, 13 and 14 correspond to the respective colors of yellow (Y), magenta (M), cyan (C) and black (K) by ROS03 as an exposure device. The laser beams 31, 32, 33, and 34 are applied to form an electrostatic latent image corresponding to the input image information for each color. When an electrostatic latent image is written on the photoconductor drums 11, 12, 13, and 14 by the ROS03, the surface potential of the image exposure portion is
The charge is removed to about -60 V or less.

An electrostatic latent image corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) formed on the surface of the photosensitive drums 11, 12, 13, and 14. Are developed by the developing devices 41, 42, 43, and 44 of corresponding colors, and yellow (Y), magenta (M), cyan (C), and black (K) are formed on the photosensitive drums 11, 12, 13, and 14, respectively. Are visualized as toner images of the respective colors.

In this embodiment, the developing devices 41, 42, 4
3, 44 adopts a magnetic brush contact type two-component developing method, but the scope of application of the present invention is not limited to this developing method. Of course.

The developing devices 41, 42, 43, and 44 contain toners of yellow (Y), magenta (M), cyan (C), and black (K) of different colors, and a developer composed of a carrier. Is filled. These developing devices 41, 42,
As shown in FIG. 2, when the toner is supplied from the toner boxes 04Y, 04M, 04C, and 04K of the corresponding colors, the supplied toner is sufficiently stirred with the carrier by the auger 404. And is triboelectrically charged. Inside the developing roll 401, a magnet roll (not shown) having a plurality of magnetic poles arranged at a predetermined angle is arranged in a fixed state. By a paddle 403 for transporting the developer to the developing roll 401,
The developer transported near the surface of the developing roll 401 is
The amount conveyed to the developing unit is regulated by the developer amount regulating member 402. In this embodiment, the amount of the developer is
30 to 50 g / m ² , and at this time, the developing roll 401
The charge amount of the toner present on the surface is approximately -20 to 35 μC / g.
It is about.

The toner supplied onto the developing roll 401 is in the form of a magnetic brush composed of carrier and toner by the magnetic force of the magnet roll, and this magnetic brush is used as the photosensitive drums 11, 12, 13, and 14. Is in contact with An AC + DC developing bias voltage is applied to the developing roll 401 to apply toner on the developing roll 401 to the photosensitive drums 11, 12, and 12.
By developing the electrostatic latent image formed on 13, 14
A toner image is formed. In this embodiment, for example,
When the AC component of the developing bias voltage is 4 kHz and 1.5 kVpp,
The DC component is set to about -230V.

In this embodiment, the developing devices 41, 4
2, 43 and 44, the toner is a so-called “spherical toner” which is a substantially spherical toner and has an average particle diameter of 3 to
For example, the average particle diameter of the black toner is set to 8 μm, and the average particle diameter of the color toner is set to 7 μm.

Next, the respective photosensitive drums 11, 12, 13, 14
The toner images of the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) formed on the first and second primary intermediate transfer drums 51 and 52 are formed.
On top, it is electrostatically secondarily transferred. The yellow (Y) and magenta (M) toner images formed on the photoconductor drums 11 and 12 are formed on the first primary intermediate transfer drum 51 by cyan (C) formed on the photoconductor drums 13 and 14. The toner images of C) and black (K) are respectively transferred onto the second primary intermediate transfer drum 52. Therefore, on the first primary intermediate transfer drum 51, the monochrome image transferred from either of the photosensitive drums 11 and 12 and the two-color toner image transferred from both of the photosensitive drums 11 and 12 are superimposed. A double-color image is formed. Further, on the second primary intermediate transfer drum 52, the same single color image and double color image are formed from the photosensitive drums 13 and 14.

The first and second primary intermediate transfer drums 5
The surface potential required for electrostatically transferring the toner image from the photosensitive drums 11, 12, 13, 14 onto the first and second photosensitive drums 1,52 is about +250 to 500V. The surface potential is set to an optimum value depending on the charged state of the toner, the ambient temperature, and the humidity. The ambient temperature and humidity can be easily known by detecting the resistance value of a member having a characteristic in which the resistance value changes depending on the ambient temperature and humidity. As described above, when the charge amount of the toner is in the range of -20 to 35 .mu.C / g and the environment is normal temperature and normal humidity, the surface potential of the first and second primary intermediate transfer drums 51 and 52 becomes , + 380V is desirable.

The first and second primaries used in this embodiment
The intermediate transfer drums 51 and 52 have, for example, an outer diameter of 42 mm.
And the resistance is 10⁸It is set to about Ω. 1st, 2nd
The primary intermediate transfer drums 51 and 52 are single-layer or
The surface consisting of flexible or elastic cylindrical
Rotating body, generally made of metal such as Fe or Al
Conductive silicone rubber on metal pipe as core
Low resistance elastic rubber layer (R = 10^Two~Ten^ThreeΩ)
Is provided with a thickness of about 0.1 to 10 mm. Furthermore,
The outermost surfaces of the first and second intermediate transfer drums 51 and 52 are typically
Is a fluoro rubber with a thickness of 3 to
100 μm high release layer (R = 10^Five~Ten⁹Ω)
And connect with a silane coupling agent-based adhesive (primer).
Is being worn. What is important here is the resistance value and surface release.
And the resistance of the high release layer is R = 10 ^Five~Ten⁹About Ω
Yes, materials are limited as long as they have high mold release properties
Not done.

The single-color or double-color toner images thus formed on the first and second primary intermediate transfer drums 51 and 52 are
The image is electrostatically tertiarily transferred onto the secondary intermediate transfer drum 53. Accordingly, on the secondary intermediate transfer drum 53, a final toner image from a single color image to a quadruple color image of yellow (Y), magenta (M), cyan (C), and black (K) is formed. Will be.

The surface potential required for electrostatically transferring the toner images from the first and second primary intermediate transfer drums 51 and 52 onto the secondary intermediate transfer drum 53 is about +600 to 1200 V. . The surface potential is the same as when the toner is transferred from the photosensitive drums 11, 12, 13, and 14 to the first primary intermediate transfer drum 51 and the second primary intermediate transfer drum 52. Will be set to the optimum value. Also, since what is necessary for the transfer is the potential difference between the first and second primary intermediate transfer drums 51, 52 and the secondary intermediate transfer drum 53, the first and second primary intermediate transfer drums 51, 5
It is necessary to set the value according to the surface potential of 2.
As described above, the charge amount of the toner is in the range of -20 to 35 .mu.C / g, and the surface potential of the first and second primary intermediate transfer drums 51 and 52 is +380 V under normal temperature and normal humidity environment. In this case, the surface potential of the secondary intermediate transfer drum 53 is about +880 V, that is, the potential difference between the first and second primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 is +880 V. It is desirable to set to about 500V.

The secondary intermediate transfer drum 53 used in this embodiment is formed, for example, to have the same outer diameter as the first and second primary intermediate transfer drums 51 and 52 of 42 mm, and has a resistance value of 10 ¹¹ Ω.
Set to about. Also, the secondary intermediate transfer drum 53 has a single-layer structure, similarly to the first and second primary intermediate transfer drums 51 and 52.
Alternatively, it is a cylindrical rotating body having a flexible or elastic surface having a plurality of layers, and is generally made of conductive silicone rubber or the like on a metal pipe as a metal core made of Fe, Al, or the like. A typical low resistance elastic rubber layer (R =
10 ² to 10 ³ Ω) in a thickness of about 0.1 to 10 mm. Further, the outermost surface of the secondary intermediate transfer drum 53 is typically made of a fluororubber in which fluororesin fine particles are dispersed and having a thickness of 3 to
It is formed as a high release layer of 100 μm, and is bonded with a silane coupling agent-based adhesive (primer). here,
The resistance value of the secondary intermediate transfer drum 53 needs to be set higher than that of the first and second primary intermediate transfer drums 51 and 52.
Otherwise, the secondary intermediate transfer drum 53 charges the first and second primary intermediate transfer drums 51 and 52, making it difficult to control the surface potential of the first and second primary intermediate transfer drums 51 and 52. Become. The material is not particularly limited as long as it satisfies such conditions.

Next, the final toner image from the single color image to the quadruple color image formed on the secondary intermediate transfer drum 53 is
The third transfer is performed by the final transfer roll 60 onto the sheet P passing through the sheet transport path. The paper P passes through a paper transport roll 90 through a paper feeding process (not shown), and is transferred to the secondary intermediate transfer drum 53.
Is transferred to the nip portion of the final transfer roll 60. After this final transfer step, the final toner image formed on the paper is fixed by the fixing device 70, and a series of image forming processes is completed.

The fixing device according to this embodiment includes a heating roller having a heating source therein, a fixing belt formed in an endless belt shape, and a belt guide rotatably supporting both ends of the fixing belt. A fixing member disposed inside the fixing belt to press the fixing belt against the surface of the heating roll; and an oil supply member for supplying oil to the inner surface of the fixing belt. In a fixing device that performs fixing by passing a recording medium carrying an unfixed toner image through a nip portion formed between belts, at least one of an outer peripheral surface of the belt guide member and an inner peripheral surface of the fixing belt is provided. It is configured to provide oil leakage prevention means for preventing oil leakage.

FIG. 4 is a perspective view showing the appearance of the fixing device according to this embodiment, and FIG. 5 is a sectional view showing the fixing device according to this embodiment.

The fixing device 70 according to this embodiment is similar to the fixing device 70 shown in FIG.
As shown in FIG. 7, a heating roll 70 having a heating source 701 therein.
2, a fixing belt 703 having an endless belt shape, a belt guide member 704 supporting both ends of the fixing belt 703 so that the fixing belt 703 is rotatable,
703, a pressing member 705 for pressing the fixing belt 703 against the surface of the heating roll 702, and a felt member 706 as an oil supply member for supplying oil to the inner surface of the fixing belt 703. It is configured. In FIG. 5, reference numeral 750 denotes an exit roll of the fixing device 70.

The heating roll 702 includes a thin cylindrical core made of iron, stainless steel, or the like, an elastic layer having a thickness of about 0.65 mm made of silicon rubber or the like coated on the surface of the core, And a release layer having a thickness of about 30 μm made of PFA or the like coated on the surface of the layer. Further, inside the heating roll 702, 60
A 0 W halogen lamp 701 is provided.

The fixing belt 703 is made of a synthetic resin such as polyimide and has an outer diameter of 30 mm and a thickness of 75 μm.
m, and is provided with a release layer made of PFA or the like, if necessary, on the surface.

Further, as shown in FIG. 6, the belt guide member 704 is constructed so as to be integrally assembled with the pressure contact member 705.

As shown in FIGS. 6 and 7, the pressure contact member 705 includes a belt housing 707 made of synthetic resin, and a metal belt having a substantially U-shaped cross section which is mounted on the belt housing 707 in a fitted state. Frame 708 and fixing belt 703
Nip head member for pressing the roller against the heating roll 702
709 and a pad member 710 attached to the nip head member 709.

The belt guide member 704 is the same as that shown in FIG.
As shown in FIG. 7, the belt frame 708 is attached to both ends of the belt housing 707 in a state of being fitted to fitting portions 708a projecting in parallel from each other at both ends of the belt frame 708.

As shown in FIGS. 8 and 9, the belt guide member 704 is provided on a cylindrical portion 711 inserted into both ends of the fixing belt 703, and is provided on the opposite side of the cylindrical portion 711. A mounting portion 712 for mounting the member 704 to a pressurizing means to be described later;
712 and two flange portions 713 and 714 provided between the two flange portions. The cylindrical portion 711 of the belt guide member 704 has an upper end 711a formed flat.
When the fixing belt 703 comes into pressure contact with the heating roll 702, the fixing belt 703 bends to form a nip portion having a predetermined width. A belt frame having a substantially U-shaped cross section is provided inside the belt guide member 704.
A concave groove 715 having a substantially U-shaped cross section is provided to be fitted to fitting portions 708a protruding in parallel with each other at both ends of the belt frame 708. Further, as shown in FIGS. 8 and 9, the belt guide member 704 has a flange portion.
Between the 713 and the flange 71, an arm 7 as a pressing member
A concave groove 716 is provided for fitting with the groove 17. 8 and 9, 760 and 761 are guides and members.
Projections are shown for attaching 704 to the belt housing 707, respectively.

The felt member 706 serving as the oil supply member is made of, for example, Nomex (trade name), and the felt member 706 is impregnated with about 2.0 g of an oil made of amino Si oil having a viscosity of 300 cs. Have been. As shown in FIGS. 5 and 7, the felt member 706 is fixed to the back side of the belt frame 708 by a means such as bonding.

Further, as shown in FIG. 10, the pressing member 705 is connected to an arm member via a belt guide member 704.
717, and the arm member 717 heats the pressure contact member 705 by a coil spring 718 to a heating roll.
It is configured to be pressed against the 702 at a predetermined pressure.
7 and 10, reference numeral 719 denotes a synthetic resin film-like sheet member interposed between the fixing belt 703 and the zero pressure contact member 705. To reduce the friction between them, but it is not always necessary to provide them.

In this embodiment, at least one of the outer peripheral surface of the belt guide member and the inner peripheral surface of the fixing belt is provided with oil leakage preventing means for preventing oil leakage. The oil leakage preventing means is constituted by a groove provided on an outer peripheral surface of the belt guide member.

That is, as shown in FIG. 1, a plurality of grooves 720 are formed on the outer peripheral surface of the cylindrical portion 711 of the belt guide member 704 in an inclined state. The inclination direction of the plurality of grooves 720 depends on the fixing belt to which the oil 721 is supplied when the fixing belt 702 rotates in a predetermined direction.
The direction is set such that the oil 712 applied to the inner surface of the fixing belt 702 in contact with the inner surface of the fixing belt 702 is sent to the inside of the fixing belt 702 along the plurality of grooves 720.

In the fixing device according to this embodiment having the above structure, the lubrication of oil or the like from the end of the fixing belt can be performed without complicating the structure of the device or increasing the cost as follows. It is possible to prevent the agent from leaking, adhering to the recording medium, and soiling the inside of the apparatus.

That is, the fixing device according to this embodiment
In FIG. 5, as shown in FIG. 5, a heating roll 702 having a heating source 701 therein, a fixing belt 703 formed in an endless belt shape, and a fixing belt 703 are provided so that the fixing belt 703 can rotate. Belt guide member supporting both ends
704, a pressure contact member 705 disposed inside the fixing belt 703 to press the fixing belt 703 against the surface of the heating roll 702, and a felt member 706 for supplying oil to the inner surface of the fixing belt 703. The fixing is performed by passing a recording medium P carrying an unfixed toner image through a nip formed between the heating roll 702 and the fixing belt 703.

At this time, in the fixing device 70, a heating roll
The fixing belt 703 is pressed against the fixing belt 703 by a pressing member 705. To reduce friction between the fixing belt 703 and the pressing member 705, a felt member 706 is attached to the inner surface of the fixing belt 703.
To apply oil 721.

Therefore, if the fixing device 70 is used for a long time, the oil 71 supplied to the inner surface of the fixing belt 703
2 gradually moves to the end of the fixing belt 703 and tries to leak from a gap with the belt guide member 704 located at the end of the fixing belt 703.

However, as shown in FIG. 1, the outer peripheral surface of the cylindrical portion 711 has
Since the plurality of grooves 720 are formed in an inclined state,
When the fixing belt 703 rotates in a predetermined direction, the oil 721 applied to the inner surface of the fixing belt 703 becomes a plurality of grooves.
It is fed to the inside of the fixing belt 703 along 720, and prevents the oil 721 from leaking from the end of the fixing belt 703.

As described above, in the above-described embodiment, the fixing belt 703 has a simple configuration in which a plurality of grooves 720 are formed on the outer peripheral surface of the belt guide member 704 in an inclined state without increasing the cost. The oil 721 can be prevented from leaking from the end of the recording medium P and adhering to the recording medium P, or soiling the inside of the apparatus.

FIG. 11 shows a modification of the first embodiment of the present invention. FIG. 11 (a) shows a groove 72 provided on the outer peripheral surface of the cylindrical portion 711 of the belt guide member 704.
0 is not formed in an inclined state, but is formed on the outer peripheral surface of the cylindrical portion 711 along a plurality of grooves 72 along the circumferential direction.
0 is formed. These grooves 720 have, for example, a width and a depth of about 0.5 mm. The plurality of grooves 720 are provided with the oil 72 applied to the inner surface of the fixing belt 703.
By keeping the fixing member 1, the oil 721 is prevented from leaking from the end of the fixing belt 703.

FIG. 11A shows a belt guide member.
One groove 720 is spirally provided on the outer peripheral surface of the cylindrical portion 711 of 704, and the inclination direction of the groove 720 is the same as that of the embodiment shown in FIG.

Second Embodiment FIG. 12 shows a second embodiment of the present invention. The same parts as those in the first embodiment will be denoted by the same reference numerals. The oil leakage prevention means is constituted by a seal member attached to the outer peripheral surface of the belt guide member.

That is, in the second embodiment, FIG.
As shown in the figure, a seal member 730 made of a very thin Mylar film or felt is provided on the outer peripheral surface of the cylindrical portion 711 of the belt guide member 704 by means such as adhesion. This sealing member 730 is, literally, the fixing belt 7.
03 is a member for sealing oil 721 from leaking from the end.

The other configuration and operation are the same as those of the first embodiment, and the description thereof will be omitted.

Third Embodiment FIG. 13 shows a third embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and described. The oil leakage preventing means is constituted by a streak provided at an axial end of the inner peripheral surface of the fixing belt.

That is, in the third embodiment, FIG.
As shown in FIG. 7, instead of providing a groove on the outer peripheral surface of the cylindrical portion 711 of the belt guide member 704, an oil leakage preventing means is provided on the inner peripheral surface 703a of the fixing belt 703. The operation of the streak-like convex portion 740 is similar to that of the cylindrical portion of the belt guide member 704.
711 is the same as the groove provided on the outer peripheral surface. Note that the streak-like convex portion 740 may be a groove.

Other configurations and operations are the same as those of the first embodiment, and therefore, the description thereof is omitted.

Fourth Embodiment FIG. 13 also shows a fourth embodiment of the present invention.
The same parts as those in the first embodiment will be described by assigning the same reference numerals. In the fourth embodiment, the oil leakage prevention means is formed by a groove provided on the outer peripheral surface of the belt guide member. It is composed.

That is, in the fourth embodiment, FIG.
As shown in the figure, a groove 741 opening toward the inside of the belt is provided only on a part of the outer circumferential surface of the cylindrical portion 711 of the belt guide member 704 along the circumferential direction. This groove 7
Reference numeral 41 denotes an edge for scraping off oil adhering to the inner surface of the fixing belt 703 and returning the oil to the inside of the belt in the axial direction. For example, as shown in FIG. 9D, the position of the groove 741 is 0 ° to 45 ° from the horizontal direction to the lower side.
(16 ° in the illustrated example).

The other configuration and operation are the same as those of the first embodiment, and the description thereof will be omitted.

[0075]

As described above, according to the present invention,
Lubricant such as oil leaks from the end of the fixing belt without complicating the configuration of the device or increasing the cost.
It is possible to provide a fixing device and an image forming apparatus using the same, which can prevent the fixing device from adhering to a recording medium and soiling the inside of the device.

[Brief description of the drawings]

FIG. 1 is a perspective configuration diagram illustrating a main part of a fixing device according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing a tandem-type full-color printer as an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a configuration diagram showing a print head device of a tandem-type full-color printer as an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 4 is an external perspective view showing a fixing device.

FIG. 5 is a sectional configuration diagram showing a fixing device according to the first embodiment of the present invention.

FIG. 6 is an external perspective view showing a pressing member.

FIG. 7 is an exploded perspective view showing a pressing member.

FIG. 8 is a configuration diagram showing a belt guide member.

FIG. 9 is a configuration diagram showing a belt guide member.

FIG. 10 is a configuration diagram showing a fixing device according to the first embodiment of the present invention.

FIG. 11 is a perspective view of a main part showing a modification of the fixing device according to the first embodiment of the present invention.

FIG. 12 is a perspective view of an essential part showing a fixing device according to a second embodiment of the present invention.

FIG. 13 is a main part perspective view showing a fixing device according to Embodiments 3 and 4 of the present invention.

[Explanation of symbols]

70: fixing device, 701: heating source, 702: heating roll, 703
: Fixing belt, 704: belt guide member, 705: pressure contact member, 706: felt member, 720: groove.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasutaka Goto 3-7-1, Fuwa, Iwatsuki-shi, Saitama Prefecture Inside Fuji Xerox Co., Ltd. (72) Takeshi Fukuda 3-7-1, Fuuchi, Iwatsuki-shi, Saitama Fuji X-Terms Co., Ltd. F-term (reference) 2H033 BA11 BA12

Claims (7)

[Claims] 1. A heating member and a pressure member, at least one of which is a belt-shaped member, and both ends of a belt-shaped member of the heating member and the pressure member. A belt guide member rotatably supporting the portion, a pressure contact member disposed inside the belt-shaped member for pressing the belt-shaped member against the surface of the other member, and supplying oil to the inner surface of the belt-shaped member. A fixing unit that fixes an image by passing a recording medium carrying an unfixed toner image through a nip portion formed between the heating member and the pressing member. A fixing device provided with an oil leakage preventing means for preventing oil from leaking on at least one of the outer peripheral surface and the inner peripheral surface of the belt-shaped member. 2. The fixing device according to claim 1, wherein the oil leakage prevention unit includes at least one groove provided on an outer peripheral surface of the belt guide member. 3. A fixing device according to claim 1, wherein said oil leakage preventing means comprises a groove provided on an outer peripheral surface of said belt guide member so as to be inclined toward the inside of the belt-shaped member. apparatus. 4. The fixing device according to claim 1, wherein said oil leakage prevention means comprises a seal member attached to an outer peripheral surface of said belt guide member. 5. The fixing device according to claim 1, wherein said oil leakage preventing means comprises a streaky projection provided on an inner peripheral surface of said belt-shaped member. 6. The fixing device according to claim 1, wherein said oil leakage preventing means comprises a groove provided on an outer peripheral surface of said belt guide member. 7. After transferring toner images of different colors formed on a plurality of image carriers onto a recording medium via a plurality of intermediate transfer members, the toner images are disposed so as to be pressed against each other, and at least one of the plurality of intermediate transfer members is pressed against each other. A heating member and a pressure member formed of a belt-shaped member, a belt guide member rotatably supporting both ends of a member formed in a belt shape among the heating member and the pressure member, and a belt-shaped member. A pressure contact member disposed inside to press the belt-shaped member against the surface of the other member;
A fixing device having an oil supply member for supplying oil to the inner surface of the belt-shaped member passes a recording medium carrying an unfixed toner image in a nip formed between the heating member and the pressure member. An image forming apparatus that forms an image by fixing the toner image on the belt, wherein the fixing device is configured to prevent oil from leaking to at least one of an outer peripheral surface of the belt guide member and an inner peripheral surface of the belt-shaped member. An image forming apparatus characterized by comprising: