JP2024077361A - Fixing device and image forming apparatus - Google Patents

Abstract

A fixing device capable of preventing the staining of a recording medium or the inside of the device due to a lubricant and suppressing wear of a fixing belt to maintain the durability of the device, and an image forming device using the same are provided.
[Solution] A fixing device 15 comprising: an endless belt member 29, a heating member 30 that heats the belt member 29, a support member 32 that supports the belt member 29 so that it can run, a pressing member 33 that is arranged on the inner circumference of the belt member 29 and presses the belt member 29 outward, a pressure member 35 that presses the pressing member 33 through the belt member 29 to form a fixing nip N in which the recording medium S is sandwiched and transported together with the belt member 29, a supply member 31 that supplies lubricant to the inner surface of the belt member 29, and a lubricant straightening member 34 that comes into contact with the supply member 31 and straightens the lubricant so that the amount of lubricant supplied from the supply member 31 to the inner surface of the belt member 29 is greater in the center than at both ends of the belt member 29.
[Selected figure] Figure 2

Description

The present invention relates to a fixing device and an image forming device.

In a conventional image forming apparatus employing an electrophotographic system, a fixing device is known in which a fixing nip is formed by a fixing belt consisting of an endless belt heated by a heating member and a pressure member in contact with the fixing belt, a recording medium with a toner image transferred thereto is passed through the fixing nip, and the toner image is fixed to the recording medium by heat and pressure.
In such a fixing device, a technology is known in which a pressing member is provided inside the fixing belt and the pressing member is made of an elastic member, and the pressing member is pressed against the pressing member via the fixing belt to form a fixing nip by elastic deformation of the pressing member, and this type of fixing device is called a sliding fixing device. In this sliding fixing device, the fixing belt runs while sliding against a fixed pressing member, and in order to reduce the frictional resistance between the fixing belt and the pressing member during movement, a technology has been proposed in which a lubricant is supplied to the inner surface of the fixing belt (see, for example, "Patent Document 1", "Patent Document 2", "Patent Document 3", "Patent Document 4", and "Patent Document 5").

Patent Document 1 discloses a fixing device having a pressure member, a fixing member, and a pressure belt, a lubricant application member that applies a lubricant to the inner surface of the pressure belt, and a pair of first blade members that come into sliding contact with the inner surface of the pressure belt to scrape off the lubricant, in order to prevent leakage of the lubricant and enable the pressure belt to run smoothly. The lubricant scraped off by the first blade members is collected by the lubricant application member.
This prevents leakage of lubricant from the end of the fixing belt and prevents the lubricant from staining the recording paper or the inside of the device, and furthermore, the scraped off lubricant is returned to the lubricant application member, making it possible to apply the lubricant stably for a long period of time.

Patent Document 2 discloses a fixing device that includes a fixing member, a heat source, a nip forming member, and a sliding member, forms a flow path for flowing a lubricant in the sliding member, and connects lubricant circulation flow paths for circulating the lubricant to both sides of the flow path, in order to prevent the lubricant from leaking from the sliding member containing the lubricant and running out. The lubricant that leaks from one side of the flow path is supplied to the other side of the flow path via the lubricant circulation flow path.
This is believed to prevent the depletion of the lubricant contained in the sliding members.

Patent Document 3 discloses a fixing device that includes a sliding sheet having fiber grooves formed in the same direction as the sliding direction of a fixing belt, and in which a lubricant circulation member holds the lubricant to be supplied to the sliding sheet on the upstream side of the nip portion, and also supplies the lubricant to the fixing belt and supplies it to the downstream side of the nip portion.
This prevents the lubricant from leaking out from both ends of the fixing belt, improves the sliding properties of the fixing belt, prevents an increase in torque during movement, and is said to extend the life of the fixing device.

Patent Document 4 discloses a fixing device that includes a fixing belt, a nip forming member, a pressure member, and a lubricant-impregnated member in order to prevent leakage of lubricant from the widthwise ends of the fixing belt, and the lubricant-impregnated member has a contact portion that contacts the inner surface of the fixing belt and a non-contact portion provided upstream of the contact portion in the belt movement direction.
This is believed to be effective in preventing the lubricant from leaking out of the fixing device.

Patent Document 5 discloses a fixing device that includes a rotating member, a belt member, and a belt guide member, and has a plurality of grooves formed on the contact surface of the belt guide member with the belt member, inclined from the upstream side to the downstream side in the rotation direction of the belt member, toward the center of the width of the belt member, in order to prevent the lubricant held by the belt member from being biased toward both ends.
This is said to ensure smooth rotation of the belt member, enabling high-quality images to be formed over a long period of time, while also preventing leakage of the lubricant to the outside, enabling the formation of fixed images with excellent gloss to be maintained.

In conventional sliding fixing devices, the inner surface of the belt slides against the pressing member, so the lubricant supplied to the inner surface of the belt is blocked at the upstream end of the pressing member in the belt running direction, and the blocked lubricant moves in the belt width direction along the end of the pressing member, gradually leaking out of the belt and adhering to the recording medium or the inside of the device, causing contamination of the recording medium and the inside of the device. In addition, there is a problem that the leakage of lubricant causes a shortage of lubricant on the inner surface of the belt, increasing the sliding resistance between the inner surface of the belt and the pressing member, which can cause the device to break down.

The technology disclosed in Patent Document 1 is said to prevent leakage of lubricant from the end of the fixing belt by the first blade member, thereby preventing the lubricant from contaminating the recording medium and the inside of the device. However, there is a problem in that the first blade member accelerates wear on the fixing belt, reducing the durability of the device.
The present invention aims to solve the above-mentioned problems and provide a fixing device that can prevent the recording medium and the inside of the device from being soiled by lubricant, and that can suppress wear on the fixing belt to maintain the durability of the device, and an image forming device using the same.

The invention described in claim 1 is characterized by comprising an endless belt member, a heating member for heating the belt member, a support member for supporting the belt member so that it can run, a pressing member disposed on the inner periphery of the belt member and pressing the belt member outward, a pressure member for pressing the pressing member through the belt member to form a fixing nip where a recording medium is sandwiched and conveyed together with the belt member, a supply member for supplying lubricant to the inner surface of the belt member, and a lubricant straightening member that comes into contact with the supply member and straightens the lubricant so that the amount of lubricant supplied from the supply member to the inner surface is greater in the center than at both ends of the belt member.

The present invention provides a fixing device and an image forming device using the same that can prevent the recording medium and the inside of the fixing device from being soiled by a lubricant, while suppressing wear on the belt member and maintaining durability.

1 is a schematic front view of an image forming apparatus according to an embodiment of the present invention; 1 is a schematic front view of a fixing device according to an embodiment of the present invention; FIG. 2 is a schematic diagram illustrating a lubricant flow guiding member used in one embodiment of the present invention. FIG. 13 is a diagram showing the correlation between the tip deviation of the sheet member and the moving speed of the lubricant according to the embodiment of the present invention. 11 is a diagram showing the relationship between the thickness of a sheet member and the presence or absence of movement of a lubricant according to an embodiment of the present invention. FIG.

Fig. 1 shows an image forming apparatus to which a fixing device according to an embodiment of the present invention can be applied. In the figure, a printer 1 as an image forming apparatus has an intermediate transfer unit 3 located approximately in the center of a device main body 2. The intermediate transfer unit 3 has an intermediate transfer belt 4 as an intermediate transfer body, which is stretched in a loop shape by a plurality of support rollers. The support rollers are composed of a drive roller 5 that drives the intermediate transfer belt 4 to run in a clockwise direction in Fig. 1, a secondary transfer backup roller 6, driven rollers 7 and 8, and four primary transfer rollers 9Y, 9M, 9C, and 9K.
The intermediate transfer belt 4 is stretched in a substantially inverted triangular shape, and above the upper belt stretching surface which corresponds to the upper side of the inverted triangle, process cartridges 10Y, 10M, 10C, and 10K for four colors, yellow, magenta, cyan, and black, are arranged in sequence in the horizontal direction.

The process cartridge 10Y houses a yellow imaging unit, and a formed yellow toner image is transferred onto the intermediate transfer belt 4. Similarly, the process cartridge 10M houses a magenta imaging unit, the process cartridge 10C houses a cyan imaging unit, and the process cartridge 10K houses a black imaging unit.
From these process cartridges 10 of each color, the toner images of each color are transferred onto the intermediate transfer belt 4 at primary transfer positions facing the primary transfer rollers 9. The color toner images primarily transferred onto the intermediate transfer belt 4 are sent to a secondary transfer section 11 as the intermediate transfer belt 4 travels.

1, a pair of exposure units 12, one for yellow and magenta and the other for cyan and black, are provided above the process cartridges 10Y, 10M, 10C, and 10K, which irradiate a photosensitive drum 17, described later, with exposure light L based on image information. The pair of exposure units 12 receive image data of each color based on image information of an original transmitted from a scanner (not shown) or the like to a control unit 21 (described later), and emit four exposure light beams L by a laser control unit and a semiconductor laser (not shown). The photosensitive drum 17 of each process cartridge 10 is scanned by the exposure light L, and electrostatic latent images of yellow, magenta, cyan, and black are written on the surface of each photosensitive drum 17, respectively.
1, reference numerals 13 and 14 denote paper feed sections that accommodate transfer sheets S, which are recording media, reference numeral 15 denotes a fixing device that fixes an unfixed toner image transferred onto the transfer sheet S by heat and pressure, and reference numeral 16 denotes a toner bottle that accommodates toner therein. The configuration and operation of the fixing device 15 will be described later.

Next, a description will be given of the process cartridge 10. Since the process cartridges 10Y, 10M, 10C, and 10K all have the same configuration except for the color of the toner used, only the process cartridge 10Y will be described here as a representative example.
A photosensitive drum 17Y, which is an image carrier, is disposed approximately in the center of the process cartridge 10Y, and a charging device 18Y for charging the photosensitive drum 17Y and a developing device 19Y for developing an electrostatic latent image formed on the surface of the photosensitive drum 17Y are disposed around the photosensitive drum 17Y. Further disposed around the photosensitive drum 17Y are a photosensitive drum cleaning device 20Y for recovering untransferred toner remaining on the surface of the photosensitive drum 17Y, and a discharging device (not shown) for discharging the surface of the photosensitive drum 17Y. Each of these members is supported by a casing, which is a common support, and is configured to be detachably attached to the apparatus main body 2 as one process cartridge 10Y, thereby improving maintainability.

Next, the operation of the printer 1 during image formation will be described. First, image information is sent from a scanner (not shown) to the control unit 21, which is a well-known microcomputer provided inside the device main body 2, and the received image information is separated into four colors: yellow, magenta, cyan, and black. Of the colors, for example, image information for yellow is converted into an electrical signal and then input to the process cartridge 10Y and sent to the exposure unit 12. From the exposure unit 12, exposure light L such as laser light based on the image information consisting of the transmitted electrical signal is irradiated toward the photosensitive drum 17Y.

1, each photoconductor drum 17 rotates counterclockwise, and its surface is uniformly charged by each charging device 18. An electrostatic latent image corresponding to image information is formed on the charged surface of each photoconductor drum 17 by irradiation with exposure light L. The formed electrostatic latent image reaches a position facing each developing device 19 by the rotation of each photoconductor drum 17, and is visualized by each developing device 19.
The toner in the developing device 19 is mixed with a carrier by an agitating member (not shown) together with toner supplied from a toner hopper (not shown), and the toner, which is frictionally charged by the mixing, is supplied together with the carrier onto a well-known developing roller. The toner carried on the developing roller passes through a well-known doctor blade to make the layer thickness uniform, and then reaches the portion facing the photosensitive drum 17, where it adheres to the electrostatic latent image formed on the surface.
In addition, toner supplied from a toner hopper not shown is appropriately supplied from a toner bottle 16 as toner is consumed in the developing device 19, and the toner consumption in the developing device 19 is detected by a toner concentration sensor consisting of an optical sensor not shown that faces the photosensitive drum 17.

The toner image formed on the surface of the photoconductor drum 17 by the developing device 19 is primarily transferred onto the intermediate transfer belt 4 at the portion facing the primary transfer roller 9. After the primary transfer process, a small amount of untransferred toner that has not been transferred to the intermediate transfer belt 4 remains on the surface of the photoconductor drum 17. After this, the surface of the photoconductor drum 17 is discharged by a discharge device (not shown), and the remaining electrostatic potential is removed and the potential is reset. After this discharge process, the surface of the photoconductor drum 17 with the untransferred toner reaches the photoconductor cleaning device 20. The photoconductor cleaning device 20 removes the residual toner adhering to the surface of the photoconductor drum 17, and has a well-known brush, roller, blade, etc. The untransferred toner adhering to the surface of the photoconductor drum 17 is removed from the surface of the photoconductor drum 17 by the brush, roller, blade, etc. of the photoconductor cleaning device 20.

The toner images of each color are primarily transferred from each process cartridge 10 onto the intermediate transfer belt 4, and the toner images of each color are superimposed to form a full-color toner image on the intermediate transfer belt 4. The formed full-color toner image is then sent to the secondary transfer unit 11 by the running movement of the intermediate transfer belt 4. At the same time, one of the paper feed units 13 and 14 is automatically or manually selected. In this embodiment, it is assumed that the paper feed unit 13 is selected.
By driving the paper feed roller 22 provided in the paper feed unit 13, one of the transfer sheets S stored in the paper feed unit 13 is fed toward the transport path K, and the transfer sheet S that has passed through the transport path K reaches the registration roller pair 23. Thereafter, by rotating the registration roller pair 23 at a predetermined timing, the transfer sheet S is fed toward the secondary transfer unit 11 at a timing aligned with the full-color toner image on the intermediate transfer belt 4.

The transfer sheet S sent to the secondary transfer section 11 is pressed against the intermediate transfer belt 4 by the secondary transfer roller 24 provided in the secondary transfer section 11 being displaced and abutting against the secondary transfer backup roller 6, and a full-color toner image is transferred onto the surface of the transfer sheet S. The transfer sheet S with the transferred toner image is sent by the transport conveyor 37 to the fixing device 15, where the transferred toner image is fixed by heat and pressure. After fixing, the sheet S is discharged onto the discharge tray 25 as an output image.
The intermediate transfer belt 4 that has passed through the secondary transfer unit 11 reaches a belt cleaning unit 26 that is disposed downstream of the secondary transfer unit 11 in the belt running direction, and residual toner is removed by a scraping blade 28 at a portion facing a guide roller 27 provided in the belt cleaning unit 26. The guide roller 27 applies a certain tension to the intermediate transfer belt 4 and facilitates the scraping operation by the scraping blade 28. The scraping blade 28 has a shorter lifespan than the intermediate transfer belt 4, and is therefore replaced as necessary. With the above operations, a series of image formation processes is completed.

Here, a description will be given of the configuration and operation of the fixing device 15. FIG.
2, the fixing device 15 has a fixing belt 29 as a belt member consisting of an endless belt, a heating roller 30 as a heating member, a supply roller 31 as a supply member, and a tension roller 32 as a support member. The fixing device 15 further has a sliding pad 33 as a pressing member, a lubricant flow regulating member 34, a pressure roller 35 as a pressure member, a guide member 36, etc. The fixing belt 29, the sliding pad 33, and the pressure roller 35 are set so that their respective overall widths, i.e., the size in the width direction of the transfer sheet S perpendicular to the sheet conveying direction, are larger than the width of the maximum size of the transfer sheet S on which an image can be formed by the printer 1.

The endless fixing belt 29 is a multi-layered belt, for example, a two-layered belt made of a base material and a release layer, or a three-layered belt made of a base material, an elastic layer, and a release layer. By providing an elastic layer on the fixing belt 29, the surface of the fixing belt 29 can be easily attached to the toner image, improving the image quality. The fixing belt 29 has a general structure, with a polyimide base material and a PFA (perfluoroalkoxyalkane) or PTFE (polytetrafluoroethylene) release layer.
The heating roller 30 includes a heater 30a therein, and the heating roller 30 heated by the heater 30a heats the fixing belt 29. The output control of the heater 30a is performed by the control unit 21 based on the detection result of the surface temperature of the fixing belt 29 in contact with the heating roller 30 detected by a temperature detection means (not shown). The heating roller 30 is rotatably supported by a frame (not shown) of the fixing device 15, and rotates when the fixing belt 29 runs.

The supply roller 31 around which the fixing belt 29 is wound comprises a metal base 31a and a supply portion 31b provided around the base 31a. The base 31a is rotatably supported by a frame (not shown) of the fixing device 15 and rotates when the fixing belt 29 is driven to run in the direction indicated by the arrow A in FIG. 2.
The supply section 31b is made of a nonwoven fabric such as felt, aramid, or polyethylene terephthalate (PET), or a fibrous body having heat resistance and oil retention such as PFA (perfluoroalkoxyalkane) or PTFE (polytetrafluoroethylene), and is impregnated with a heat-resistant low-viscosity lubricant such as amino silicone oil. The lubricant impregnated in the supply section 31b is appropriately supplied from a lubricant storage section (not shown) provided in the fixing device 15.
The tension roller 32 around which the fixing belt 29 is stretched is rotatably supported by a support member (not shown), and this support member is movably supported by a frame (not shown) of the fixing device 15. A compression spring 32a that urges the tension roller 32 leftward in FIG. 2 is attached to the support member (not shown), so that a predetermined tension is applied to the fixing belt 29 by the tension roller 32.

The sliding pad 33 is fixed to a frame (not shown) of the fixing device 15 by a support member (not shown). This allows the position of the sliding pad 33 to remain unchanged even when pressure is applied by a pressure roller 35 (described later), making it possible to obtain a fixing nip of uniform width. The width of the fixing nip can be controlled by controlling the pressing force of the pressure roller 35.
The sliding pad 33 has a nip forming surface along the transport direction of the transfer sheet S, and a fluororesin layer is provided on the nip forming surface to reduce the sliding resistance with the fixing belt 29, and both ends of the nip forming surface are curved. In this embodiment, the nip forming surface is curved, but it may be flat. If it is curved, it is formed to the extent that it does not interfere with the transport of the transfer sheet S.

The sliding pad 33 is preferably made of a heat-resistant material, which prevents deformation due to heat in the toner fixing temperature range and ensures a stable fixing nip, thereby stabilizing the output image.
Examples of heat-resistant materials that can be used to form the sliding pad 33 include common heat-resistant resins such as polyethersulfone (PES), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyethernitrile (PEN), polyamideimide (PAI), and polyetheretherketone (PEEK).

The lubricant flow guiding member 34 is provided near the outer circumferential surface of the fixing belt 29 on the upstream side in the belt running direction from the position where the supply roller 31 contacts the inner circumferential surface of the fixing belt 29. The lubricant flow guiding member 34 will be described later.
The pressure roller 35 is disposed at a position facing the sliding pad 33 via the fixing belt 29 on the outer periphery of the fixing belt 29, and is configured to be able to press against and separate from the sliding pad 33 via the fixing belt 29. The pressure roller 35 is an elastic body having an elastic layer made of, for example, silicone rubber on its outer periphery, and elastically deforms when pressed against the sliding pad 33 via the fixing belt 29 to form a fixing nip N shown in FIG. 2. The pressure roller 35 is rotatably supported by a side plate (not shown) that is provided so as to be able to swing freely, and is driven to rotate by a driving means such as a motor (not shown) attached to the side plate. When the pressure roller 35 presses against the sliding pad 33 via the fixing belt 29 due to the operation of the contacting and separating means (not shown), the rotational force of the pressure roller 35 is transmitted, and the fixing belt 29 is driven to run in the direction of the arrow in FIG. 2.
A guide member 36 made of a plate-like member fixed to a side plate (not shown) of the fixing device 15 guides the transfer sheet S transported by a transport conveyor 37 toward the fixing nip N.

In FIG. 2, the refresh roller 38 and the refresh counter roller 39, each indicated by a two-dot chain line, are arranged to face each other across the fixing belt 29. The refresh counter roller 39 is arranged with its circumferential surface close to the inner circumferential surface of the fixing belt 29, and the refresh roller 38 selectively occupies a separation position where its circumferential surface is separated from the outer circumferential surface of the fixing belt 29 and a contact position where it contacts the refresh counter roller 39 across the fixing belt 29 by a contact/separation means (not shown). The refresh roller 38 has an uneven surface, and when it occupies the contact position, it brings the uneven surface into contact with the outer circumferential surface of the fixing belt 29, polishing the outer circumferential surface (surface) of the running fixing belt 29 and restoring the surface properties. The refresh roller 38 and the refresh counter roller 39 can be omitted.

The rotating pressure roller 35 presses against the sliding pad 33 via the fixing belt 29, driving the fixing belt 29 to run and rotating the heating roller 30, and further supplying lubricant from the supply section 31b to the inner surface of the fixing belt 29. The transfer sheet S sent to the fixing device 15 by the transport conveyor 37 is guided to the fixing nip N by the guide member 36, and is transported through the fixing nip N as the pressure roller 35 rotates. At this time, heat is transmitted from the heater 30a to the transfer sheet S via the heating roller 30 and the fixing belt 29, melting the transferred toner on the transfer sheet S, and the toner image is fixed on the transfer sheet S by interaction with the pressure from the pressure roller 35.

In the above-mentioned configuration, the lubricant supplied to the inner surface of the fixing belt 29 by the supply roller 31 is blocked at the upstream end of the sliding pad 33 in the belt running direction, and the blocked lubricant moves widthwise along the end of the sliding pad 33, gradually leaking out of the fixing belt 29 and causing damage to the recording medium and the inside of the device. In addition, if the lubricant in the fixing belt 29 is depleted due to leakage, the frictional resistance between the sliding pad 33 and the fixing belt 29 increases, accelerating wear of the fixing belt 29 and reducing the durability of the fixing belt 29 and the fixing device 15.

The lubricant flow guide member 34 of the present invention, which prevents the above-mentioned problems from occurring, will now be described.
2 as viewed from the direction of the arrow B, the lubricant flow straightening member 34 is composed of a holding portion 34a and two blades 34b as sheet members fixed to the holding portion 34a. The holding portion 34a, which is made of a material having strength such as metal or hard resin, is fixed to a frame (not shown) of the fixing device 15, and each blade 34b, which is made of a thin elastic sheet material such as Mylar, is disposed in such a manner that its tip is in contact with the circumferential surface of the supply roller 31.
Each blade 34b is formed so that its outer end in the width direction is located inside both ends of the supply roller 31, and a predetermined gap is provided at each center. The amount of protrusion of each blade 34b in the belt running direction indicated by arrow A, i.e., the amount of contact with the circumferential surface of the supply roller 31, is shortest at both ends and increases toward the center.

Here, an experiment in which the shape of the blade 34b was determined as described above will be described. In the experiment, a Kapton sheet (registered trademark), which is a sheet material having excellent heat resistance, cold resistance, oil resistance, and durability, was used as the blade 34b.
4 is a graph showing the relationship between the tip deviation of the blade 34b, which is a sheet member, and the lubricant movement speed. In the figure, the tip deviation of the sheet member indicates the value obtained by subtracting the protrusion amount of the blade 34b at the end from the protrusion amount of the blade 34b at the center. In this experiment, the blade 34b used had a thickness of 100 μm.

As can be seen from Figure 4, the shorter the protrusion of blade 34b, the higher the contact pressure on supply roller 31 due to the effect of the rigidity of the sheet material. The lubricant then moves from the higher pressure side to the lower pressure side. Therefore, if the protrusion of blade 34b is made shorter near the ends compared to the center, the lubricant moves from the ends toward the center. It was found that there is a correlation between the tip deviation of the sheet material and the movement speed of the lubricant, and the greater the tip deviation, the greater the deviation in the contact pressure of the sheet material and the greater the movement speed of the lubricant.

For this reason, by forming the amount of contact of each blade 34b with the peripheral surface of the supply roller 31 to be shortest at both ends and to become longer toward the center, the amount of lubricant supplied from the supply roller 31 to the inner surface of the fixing belt 29 can be made greater at the center than at both ends of the fixing belt 29.
This makes it possible to prevent the lubricant from leaking from both ends of the fixing belt 29, thereby preventing the transfer sheet S and the inside of the fixing device 15 from being soiled by the lubricant, and also makes it possible to provide a fixing device 15 and an image forming apparatus 1 using the same that can suppress wear on the fixing belt 29 and maintain its durability.

5 is a table showing the results of an experiment conducted to determine the relationship between the thickness of the blade 34b and the presence or absence of movement of the lubricant. The experiment was conducted using five types of blades 34b having thicknesses of less than 50 μm, 100 μm, 200 μm, 300 μm, and 400 μm as the sheet member.
As can be seen from FIG. 5, if the thickness is less than 50 μm, the rigidity of the sheet member is too low, and there is no deviation in the contact pressure between the center and the end in the width direction, and the lubricant does not move. Also, if the thickness is 400 μm or more, the rigidity of the sheet member is too high, and the sheet member scrapes off all the lubricant, so the lubricant does not move. From this, it was found that a sheet member having a thickness of 50 to 300 μm is suitable as a sheet member applicable to the blade 34b. By setting the thickness to this value, the above-mentioned effect can be achieved, that is, the effect of being able to prevent the transfer sheet S and the inside of the fixing device 15 from being soiled by the lubricant, and being able to suppress wear of the fixing belt 29 and maintain durability, and the effect of being able to provide a fixing device 15 and an image forming apparatus 1 using the same can be achieved.

In the above embodiment and modified example, an example has been shown in which a full-color printer 1 is used as an image forming apparatus to which the present invention can be applied, but the image forming apparatus to which the present invention can be applied is not limited to this, and the present invention can also be applied to copying machines, facsimiles, multi-function machines, etc.
In the above embodiment, a configuration is shown in which a transfer sheet S is used as the recording medium on which an image is formed, but this transfer sheet S is not limited to recording paper, but also includes cardboard, postcards, roll paper, envelopes, plain paper, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheets, OHP film, resin films, etc., and any sheet-like material on which an image can be formed may be used.

For example, aspects of the present invention are as follows.
[1] A fixing device comprising: an endless belt member; a heating member for heating the belt member; a support member for supporting the belt member so that it can run; a pressing member disposed on an inner periphery of the belt member and pressing the belt member outward; a pressure member for pressing the pressing member through the belt member to form a fixing nip in which a recording medium is sandwiched and transported together with the belt member; a supply member for supplying a lubricant to an inner surface of the belt member; and a lubricant straightening member for contacting the supply member and straightening the lubricant supplied from the supply member to the inner surface so that the amount of lubricant supplied to the inner surface from the supply member is greater in the center than at both ends of the belt member.
[2] The fixing device described in [1], wherein the lubricant straightening member has a sheet member that contacts the supply member, and the amount of contact of the sheet member with the supply member is short at both ends in the width direction and becomes longer toward the center.
[3] The fixing device according to [2], wherein the sheet member has a thickness of 50 to 300 μm.
[4] An image forming apparatus comprising the fixing device according to any one of [1] to [3].

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the spirit of the present invention described in the claims, unless otherwise specifically limited in the above description.
The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

1. Image forming device (printer)
15 Fixing device 29 Belt member (fixing belt)
30 Heating member (heating roller)
31 Supply member (supply roller)
32 Support member (tension roller)
33 Pressing member (sliding pad)
34 Lubricant flow regulating member 34b Sheet member (blade)
35 Pressure member (pressure roller)
N: Fixing nip S: Recording medium (transfer sheet)

Patent No. 5040304 JP 2014-174434 A JP 2014-174358 A JP 2017-125919 A JP 2006-78965 A

Claims (4)

An endless belt member;
a heating member for heating the belt member;
a support member that supports the belt member so that the belt member can run;
a pressing member disposed on an inner circumferential portion of the belt member and pressing the belt member outward;
a pressing member that presses the pressing member via the belt member to form a fixing nip in which a recording medium is sandwiched and conveyed together with the belt member;
a supply member for supplying a lubricant to an inner surface of the belt member;
a lubricant flow straightening member that comes into contact with the supply member and straightens the flow of the lubricant so that the amount of the lubricant supplied from the supply member to the inner surface is greater at a center portion of the belt member than at both end portions of the belt member;
A fixing device comprising: 2. The fixing device according to claim 1,
the lubricant flow straightening member has a sheet member that contacts the supply member, and the amount of contact of the sheet member with the supply member is short at both ends in the width direction and becomes longer toward the center. 3. The fixing device according to claim 2,
The fixing device is characterized in that the sheet member has a thickness of 50 to 300 μm. An image forming apparatus comprising the fixing device according to any one of claims 1 to 3.

Images