JP2008281617A - Image heating device and method for manufacturing guide member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image heating device of film heating type in which a fixing film or pressure roller is prevented from slipping on a sheet material while securely applying heat to an image on the sheet material with a simple configuration. <P>SOLUTION: The image heating device includes: a flexible fixing film 22; a ceramic heater 23 that slides on the inner circumferential face of the fixing film 22; a stay member 21 which is disposed inside the fixing film 22, to which the ceramic heater 23 is attached, and which slides on the inner circumferential face of the fixing film 22 to guide the rotation of the fixing film 22. In the image heating device, the sliding face between the stay member 21 and the fixing film 22 is roughened, and the ten-point average roughness Rzjis of the sliding face is 10 &mu;m or larger. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an image heating apparatus that applies heat to an image formed on a sheet material, and a method of manufacturing a guide member provided in the image heating apparatus.

  Conventionally, there has been known an image heating apparatus that heats an image formed on a sheet material to thermally fix the image on the sheet material or adds gloss to an image formed on the sheet material. ing.

  Such an image heating apparatus includes a heat roller having a heating member such as a halogen lamp inside, and a pressure roller that is pressed against the heat roller, and applies heat to the image at the nip between the heat roller and the pressure roller. Those having a heat roller system are widely used. In addition to the heat roller method, an image heating apparatus having a heating method such as a flash heating method, an open heating method, or a hot plate heating method is known.

  Among them, recently, a heat-resistant thin fixing film is directly brought into contact with a heating member such as a heater, and a sheet material is sandwiched in a nip formed by the fixing film and a pressure roller that is pressed against the fixing film. An image heating apparatus that heats an image on a sheet material is known. Such a heating system is called a film heating system (see Patent Document 1 and Patent Document 2).

  In the film heating type image heating apparatus, a ceramic substrate (ceramic heater) having a heating resistor formed on the surface is used as the heating member, and the ceramic heater is raised to a desired temperature by energizing the heating resistor. It is the structure which makes it warm.

  Thus, the film heating type image heating apparatus uses a ceramic heater or a fixing film having a small heat capacity, so that it takes a relatively short time for these members to reach a predetermined temperature and has excellent quick start characteristics. . In addition, even after reaching the predetermined temperature, it becomes possible to maintain these members at the predetermined temperature with less power consumption, and thus energy saving is excellent.

  Also, in the film heating type image heating apparatus, a cylindrical film is used as the fixing film, and the fixing film is rotated around the pressure roller by causing the pressure roller to come into pressure contact with the fixing film and rotating the pressure roller. A configuration (pressure roller drive system) is often used. A guide member for guiding the rotation of the fixing film is provided inside the fixing film.

  Compared with a configuration (film driving method) in which the fixing film is driven and the pressure roller is rotated around the fixing film (film driving method), the pressure roller driving method has a smaller number of parts constituting the apparatus main body. Therefore, there is an advantage that the manufacturing cost can be reduced.

  In addition, the film heating type image heating apparatus has a configuration in which a sheet material is nipped and conveyed in a nip portion formed by a pressure roller and a fixing film. That is, the sheet material is conveyed to the sheet material by applying a frictional force in the conveying direction from each of the pressure roller and the fixing film.

On the other hand, the fixing film has a ceramic heater and a guide member inside, and these members and the fixing film are directly rubbed. Therefore, sliding frictional resistance is generated on the fixing film from the ceramic heater and the guide member in the direction opposite to the rotation direction of the fixing film.

  That is, if the sliding frictional resistance is too large, the fixing film cannot be rotated with the pressure roller, and the fixing film slips. Then, the fixing film slips to cause a sheet passing defect of the sheet material.

  As a countermeasure, an image heating apparatus in which a lubricant such as grease is interposed between the fixing film and the ceramic heater in order to reduce sliding friction resistance between the fixing film and the ceramic heater and between the fixing film and the guide member. It has been known.

According to this configuration, the sliding friction between the fixing film, the ceramic heater, and the guide member can be reduced by the lubricant interposed between the fixing film and the ceramic heater. Can be rotated. Therefore, the sheet passing state of the sheet material can be maintained in a good state.
JP-A-4-44075 JP-A-4-204980 JP 2001-341143 A Japanese Patent No. 3483413

  However, in recent years, an image heating apparatus using a low torque motor as a drive motor for driving a pressure roller has been proposed for the purpose of reducing manufacturing costs. Thus, in order to drive the pressure roller with a low torque drive motor and to reliably rotate the fixing film, it is required to reduce the pressure applied to the fixing film by the pressure roller.

  Further, in order to extend the durable life of the image heating apparatus main body, it is required to reduce the pressure applied by the pressure roller.

  However, if the pressure applied to the fixing film by the pressure roller is reduced, the frictional force between the sheet material and the pressure roller and between the sheet material and the fixing film is reduced, so that the pressure roller and the fixing film slip against the sheet material. Resulting in.

  When the slip occurs, it becomes impossible to nipping and conveying the sheet material by the pressure roller and the fixing film, resulting in poor sheet passing. Furthermore, image defects such as image shrinkage and image rubbing of the image formed on the sheet material also occur.

  In order to prevent this, it is conceivable to reduce the sliding friction resistance between the fixing film and the ceramic heater and between the fixing film and the guide member. By reducing the sliding frictional resistance, the fixing film can be reliably rotated around the pressure roller even if the torque of the pressure roller is reduced. It is also conceivable to directly drive the film by adopting a film driving system.

  For example, Patent Document 3 discloses a configuration of an image heating apparatus in which the inner surface of a fixing film is roughened. By roughening the inner surface of the fixing film in this manner, the lubricant can be held on the inner surface of the fixing film, and the lubricant can circulate stably on the inner surface of the fixing film.

  Therefore, the sliding friction resistance between the fixing film and the ceramic heater and between the fixing film and the guide member can be reduced, so that the possibility of slipping is low.

  However, in this configuration, since the contact area between the fixing film and the heater is reduced by roughening the inner surface of the fixing film, it is difficult to efficiently transfer heat from the heater to the fixing film. That is, it becomes difficult to reliably apply heat to the image on the sheet material.

  Patent Document 4 discloses a configuration in which grooves are provided at equal intervals on the surface of the guide member so that the lubricant is easily interposed between the fixing film and the guide member.

  According to this configuration, since the lubricant can stably circulate on the inner surface of the fixing film, the sliding friction resistance between the fixing film and the ceramic heater and between the fixing film and the guide member can be reduced. And slip is unlikely to occur.

  However, in this configuration, the way in which heat is transmitted to the inner surface of the fixing film differs between the groove portion where the lubricant is accumulated and the other portion. That is, the inner surface of the fixing film that comes into contact with a portion where a large amount of lubricant is accumulated is difficult to transmit heat to the film because the lubricant is present. On the other hand, on the inner surface of the fixing film that comes into contact with a portion having a small amount of lubricant, heat is easily transferred to the film because there is little intervention of the lubricant.

  As a result, temperature unevenness occurs on the surface of the fixing film, and when heat is applied to the image on the sheet material, the amount of heat applied varies depending on the portion of the image. Heat cannot be applied to

  In the film driving method, film shift control, drive control, and the like are complicated, so that the manufacturing cost is greatly increased.

  That is, in the image heating apparatus of the film heating method according to the conventional example, the fixing film or the pressure roller slips with respect to the sheet material with a simple configuration while reliably applying heat to the image on the sheet material. The configuration for preventing this is not disclosed.

  In the image heating apparatus of the film heating system, the fixing film or the pressure roller slips with respect to the sheet material while reliably applying heat to the image on the sheet material with a simple configuration. An object of the present invention is to provide an image heating apparatus for preventing the above.

  It is another object of the present invention to provide a method for manufacturing a guide member that is used in an image heating apparatus and that guides rotation of a fixing film and to which a ceramic heater is attached.

  In order to achieve the above object, in the present invention, a flexible sleeve-shaped rotating member, a heating member that slides on the inner peripheral surface of the rotating member, and an inner side of the rotating member, An image heating apparatus comprising: a guide member that is attached to the heating member and that slides with an inner peripheral surface of the rotating member to guide rotation of the rotating member; and a sliding surface of the guide member with the rotating member Is characterized (including the case where both ends of the guide member are not roughened), and the 10-point average roughness Rzjis of the sliding surface is 10 μm or more.

Also provided inside the flexible sleeve-shaped rotating member used in the image heating device, sliding on the inner peripheral surface of the rotating member to guide the rotation of the rotating member, In the manufacturing method of the guide member in which the heating member is attached to at least a part of the sliding surface, the wall surface forming the cavity, the portion corresponding to the sliding surface with the rotating member in the guide member is roughened By performing mold forming using the formed mold, the 10-point average roughness Rzjis of the sliding surface of the guide member with the rotating member is set to 10 μm or more.

  According to the present invention, in a film heating type image heating apparatus, the fixing film or the pressure roller slips with respect to the sheet material while reliably applying heat to the image on the sheet material with a simple configuration. It becomes possible to prevent this.

  The best mode for carrying out the present invention will be exemplarily described in detail below based on the embodiments with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

(First embodiment)
The image heating apparatus and the guide member manufacturing method according to the first embodiment of the present invention will be described with reference to FIGS. Here, as an embodiment of the image heating apparatus according to the present invention, a case where the image heating apparatus is applied to a fixing unit of an image forming apparatus will be described.

[Description of image forming apparatus]
The configuration of the image forming apparatus in the present embodiment will be described with reference to FIG. FIG. 2 shows a schematic configuration of a laser beam printer using an electrophotographic process as an image forming apparatus in the present embodiment. In this embodiment, an image forming apparatus capable of developing an image only on one side of a sheet material is taken as an example.

  When an image is formed on a sheet material P in a laser beam printer, first, the laser beam scanner 3 is a photosensitive drum as an image carrier based on image information input from an external device such as an image scanner / computer (not shown). 1 is irradiated with a laser beam L.

  The surface of the photosensitive drum 1 is charged to a predetermined potential in advance by a charging roller 2 provided as a charging member (primary charging), and an electrostatic latent image is formed on the surface when the laser beam L is irradiated. . Further, the photosensitive drum 1 rotates at a predetermined peripheral speed (process speed) in the arrow direction (clockwise direction) in FIG.

  Then, a toner agent is supplied to the electrostatic latent image from a developing sleeve 4a provided in the developing device 4, and the electrostatic latent image on the surface of the photosensitive drum 1 is developed as a toner image. In the case of a laser beam printer, a reversal development method is generally used in which a toner agent is attached to an exposed bright portion of an electrostatic latent image for development.

  The toner image developed on the photosensitive drum 1 is transferred onto the sheet material P at the nip (transfer portion T) between the photosensitive drum 1 and the transfer roller 9. At the time of transfer, a transfer voltage (transfer bias) controlled to a predetermined value is applied to the transfer roller 9 from a transfer bias application power source (not shown). The configuration of the transfer roller 9 and the control of the transfer voltage will be described later.

  The sheet material P to which the toner image has been transferred passes through the sheet path 8b and is conveyed to the fixing unit 11. Note that the toner agent remaining on the photosensitive drum 1 without being transferred is cleaned by a cleaning device 10 that cleans the surface of the photosensitive drum 1.

A plurality of sheet materials P are stacked in the feeding cassette 5 and pass through the feeding roller 6, the registration roller 7, and the sheet path 8a based on a feeding start signal, and are transferred to the transfer unit T at a predetermined timing. Be transported.

  The fixing unit 11 is provided with the image heating apparatus according to the present embodiment, and applies heat to the toner image transferred onto the conveyed sheet material P. The toner image is permanently fixed on the sheet material P, passes through the sheet path 8c, and is discharged from the discharge port 13 onto the discharge tray.

  The configuration of the transfer roller 9 in the present embodiment will be described.

In general, for contact-type and rotary-type transfer rollers, the resistance is adjusted to about 1 × 10 ⁶ to 1 × 10 ¹⁰ Ω on the outer periphery of a core metal such as SUS or Fe with carbon, ion conductive filler, or the like. An elastic sponge roller provided with a semiconductive sponge elastic layer is used.

In this embodiment, an ion conductive transfer roller 9 is configured by providing a conductive elastic layer 9a formed by reacting NBR rubber and a surfactant on the outer periphery of the metal core 9b in a roller shape. did. The resistance value was in the range of 1 × 10 ^{8 to} 5 × 10 ⁸ Ω.

  In general, it is known that the resistance of the transfer roller is likely to fluctuate depending on the temperature and humidity of the atmospheric environment. If the resistance of the transfer roller fluctuates, problems such as transfer failure and paper traces occur.

  Therefore, in the present embodiment, in order to prevent the occurrence of transfer failure and paper marks due to the resistance fluctuation of the transfer roller 9, the resistance value of the transfer roller 9 is measured in advance, and the transfer roller 9 is measured according to the measurement result. The applied transfer voltage control for appropriately controlling the transfer voltage applied to the sensor is employed.

  In addition, ATVC control (Active Transfer Voltage Control) is known as such applied transfer voltage control (see JP-A-2-123385), and in this embodiment, ATVC control is used as transfer voltage control.

  The ATVC control is a means for optimizing the transfer bias applied to the transfer roller at the time of transfer, and prevents the occurrence of transfer defects and paper marks.

  Specifically, during standby of the image forming apparatus, a desired constant current bias is applied from the transfer roller to the photosensitive drum, the resistance of the transfer roller is detected from the bias value at that time, and the transfer bias corresponding to the resistance value at the time of transfer is detected. Is applied to the transfer roller.

  According to this control configuration, it is possible to prevent the occurrence of problems such as transfer defects and paper marks due to resistance variation of the transfer roller 9.

[Description of image heating device]
With reference to Fig.1 (a), the structure of the image heating apparatus which concerns on this Embodiment is demonstrated. Fig.1 (a) is a schematic block diagram in the cross section of the image heating apparatus which concerns on this Embodiment.

(Overall configuration of image heating device)
As described above, in the present embodiment, the image heating apparatus is applied to the fixing unit 11 of the image forming apparatus. Hereinafter, the overall configuration of the image heating apparatus according to the present embodiment will be described.

The image heating apparatus according to the present embodiment is a tensionless type image heating apparatus, and includes a cylindrical fixing film 22 (sleeve-like rotating member) and a pressure roller 24 (pressing pressure) that is in pressure contact with the fixing film 22. Member). The fixing film 22 has flexibility and heat resistance, and at least a part of the circumference of the fixing film 22 is always held in a tensionless state (a state where no tension is applied).

  Then, the pressure roller 24 comes into pressure contact with the fixing film 22, and the pressure roller 24 is driven to rotate, so that the fixing film 22 rotates with the pressure roller 24.

  A stay member 21 is provided inside the fixing film 22 as a guide member for guiding the rotation of the fixing film 22. The stay member 21 has a shape extending along the longitudinal direction of the fixing film 22, and the fixing film 22 is fitted on the stay member 21.

  In addition, the inner peripheral length of the fixing film 22 is set to be about 3 mm longer than the outer peripheral length of the stay member 21, so that the fixing film 22 can be loosely fitted to the stay member 21.

  Further, a plate-shaped ceramic heater 23 as a heating member is attached along the longitudinal direction of the stay member 21. That is, the stay member 21 holds the ceramic heater 23 while guiding the rotation of the fixing film 22 and is made of a material having rigidity and heat resistance.

  Further, a lubricant is interposed between the fixing film 22 and the stay member 21 to reduce the sliding friction resistance on the sliding surface of the fixing film 22 and the stay member 21. In this embodiment, PEPE (perfluoropolyether) grease thickened with fluororesin PTFE is used.

(Structure of fixing film)
The fixing film 22 (sleeve-like rotating member) in the present embodiment has a film thickness of 100 μm or less in order to improve the quick start property of the image heating apparatus. In this embodiment, the outer peripheral surface of a polyimide film having a film thickness of about 50 μm is coated with PTFE, and the outer diameter of the fixing film 22 is 18 mm.

  In addition to the above configuration, a single layer film such as PTFE, PFA, or FEP having heat resistance of 20 μm or more and 50 μm or less may be used. Furthermore, the structure which uses the composite layer film which coat | covered PTFE, PFA, FEP etc. on the outer peripheral surface of films, such as a polyimide, a polyamideimide, PEEK, PES, and PPS, may be sufficient.

(Configuration of pressure roller)
The pressure roller 24 (pressure member) in the present embodiment forms a nip portion N by being pressed against the fixing film 22. Further, the ceramic heater 23 provided inside the fixing film 22 directly contacts the nip portion N inside the fixing film 22 (FIG. 1A).

  Then, the pressure roller 24 is rotationally driven in the direction of the arrow in FIG. 1A at a predetermined peripheral speed, so that the fixing film 22 moves to the pressure roller 24 at substantially the same speed as the rotation speed of the pressure roller 24. Take around. When the fixing film 22 is rotated, the inner peripheral surface of the fixing film 22 and the ceramic heater 23 are rubbed.

  The pressure roller 24 is formed of a cored bar, an elastic layer that covers the periphery of the cored bar, and an outermost release layer, and is fixed with a predetermined pressing force by a bearing unit and a biasing unit (not shown). Press contact with the film 22.

In this embodiment, aluminum is used for the core metal, silicone rubber is used for the elastic layer, and a PFA tube having a thickness of about 30 μm is used for the release layer. The outer diameter of the pressure roller 24 was 20 mm, and the thickness of the elastic layer was 3 mm.

(Configuration of ceramic heater)
FIG. 3 is a front view of the ceramic heater 23 (heating member) and a circuit for performing energization control in the present embodiment.

  The ceramic heater 23 includes a plate-shaped ceramic substrate 27 on which a heating resistor 26 is formed along the longitudinal direction. The ceramic substrate 27 is arranged so that its longitudinal direction is perpendicular to the conveying direction of the sheet material P (the direction of arrow a in FIG. 3).

  The ceramic substrate 27 is made of a material having heat resistance, insulation, and good thermal conductivity. In this embodiment, alumina is used as a material constituting the ceramic substrate 27. However, the structure using ceramic materials, such as aluminum nitride, may be sufficient. The dimensions of the ceramic substrate 27 are 7 mm in width, 270 mm in length, and 1 mm in thickness.

  The surface on which the heating resistor 26 is formed on the ceramic substrate 27 is protected by the overcoat layer 28. The overcoat layer 28 is provided to ensure electrical insulation of the ceramic heater 23 and slidability of the fixing film 22. In the present embodiment, a heat-resistant glass layer having a thickness of about 50 μm is used as the overcoat layer 28.

  In addition, power supply electrodes 29 and 30 are formed at both ends of the heating resistor 26. The power feeding electrodes 29 and 30 are connected to an AC power source 33, and power is supplied from the AC power source 33. In the present embodiment, the power feeding electrodes 29 and 30 are formed on both ends of the heating resistor 26 by a screen printing pattern of silver palladium.

The heating resistor 26 in the present embodiment is formed by forming a paste prepared by kneading silver, palladium, glass powder (inorganic binder), and organic binder into a line band shape on the ceramic substrate 27 by screen printing. It is obtained. In addition, as a material of the heating resistor 26, an electric resistance material such as RuO ₂ or Ta ₂ N may be used in addition to silver palladium (Ag / Pd). The resistance value of the heating resistor 26 was 20Ω at room temperature.

  In the present embodiment, the temperature of the ceramic heater 23 can be measured by the thermistor 25 as a temperature measuring element. The thermistor 25 is not directly attached to the ceramic heater 23, but is provided separately from the ceramic heater 23.

  The thermistor 25 in the present embodiment is configured such that a ceramic paper having heat insulation is provided on a highly heat-resistant liquid crystal polymer, and an element of the chip thermistor is fixed thereon. When the temperature of the ceramic heater 23 is measured, the temperature of the ceramic heater 23 can be measured by pressing the element side against the back side of the ceramic heater 23 (the side where the heating resistor 26 is not formed). The thermistor 25 is provided in the minimum sheet passing area and is connected to the CPU 31.

  And the ceramic heater 23 comprised as mentioned above is attached to the lower surface side of the stay member 21 so that the surface where the heating resistor 26 is formed may be on the lower side (FIG. 1A).

  According to this configuration, the surface on which the heating resistor 26 is formed and the inner peripheral surface of the fixing film 22 are rubbed, and heat is applied to the image on the sheet material from the ceramic heater 23 via the fixing film 22. It becomes possible.

  Hereinafter, the process of applying heat to the image on the sheet material by the ceramic heater 23 will be described.

  When the AC power source 33 energizes the heating resistor 26 from the power supply electrodes 29 and 30 and the ceramic heater 23 is heated, the thermistor 25 detects the temperature rise of the ceramic heater 23.

  Then, a signal obtained by A / D converting the output of the thermistor 25 is taken into the CPU 31, and the electric power supplied to the heating resistor 26 by the triac 32 based on the information is controlled by phase control or wave number control, etc. Temperature control is performed.

  In other words, the ceramic heater 23 can be kept at a constant temperature by controlling energization so that the temperature rises when the temperature detected by the thermistor 25 is lower than a predetermined set temperature, and the temperature is lowered when the temperature is higher than the set temperature. .

  In the present embodiment, the output is changed in 21 steps in increments of 5% in the range of 0 to 100% by phase control. The output 100% indicates the output when the ceramic heater 23 is fully energized.

  When the temperature of the ceramic heater 23 rises to a predetermined temperature and the rotational peripheral speed of the fixing film 22 is stabilized, the sheet material P as the material to be heated is conveyed to the nip portion N between the fixing film 22 and the pressure roller 24.

  The sheet material P is nipped and conveyed by the fixing film 22 and the pressure roller 24, so that the heat of the ceramic heater 23 is applied to the sheet material P through the fixing film 22, and the toner image on the sheet material P is transferred. The sheet material P is fixed by heating. Then, the sheet material P that has passed through the nip portion N is separated from the fixing film 22 and discharged to the discharge portion 14.

(Configuration of guide member)
FIG. 1B shows a perspective view of a stay member 21 as a guide member.

  The stay member 21 is made of a high heat resistant resin such as polyimide, polyamideimide, PEEK, PPS, or liquid crystal polymer, or a composite material of these resins and ceramics, metal, glass, or the like.

  In the present embodiment, the stay member 21 is formed by injection molding in which liquid crystal polymer is injected into a mold to perform mold forming.

  Further, the wall surface of the cavity of the mold used in the injection molding is roughened, and the surface shape of the roughened wall surface is transferred to the stay member 21 at the time of injection molding. The sliding surface with the fixing film 22 can be roughened.

  As a method of roughening the mold surface, the mold surface is corroded with chemicals, then the etching process that engraves the pattern, the sandblasting process that sprays sand or glass beads, and the honing process are combined. Is known.

  As a result, a geometric pattern such as a line or a pattern, a satin pattern, a grained pattern, or the like can be formed on a portion of the wall surface of the mold cavity corresponding to the sliding surface of the stay member 21. Furthermore, by performing injection molding using this mold, it becomes possible to form a stay member having a roughened surface.

  It is also possible to obtain a stay member having a roughened surface by directly treating the surface of the stay member by sandblasting or honing.

  In the present embodiment, the wall surface of the cavity of the mold is roughened so that the satin surface (HN series, CN-1: Nippon Etching Co., Ltd.) is formed on the sliding surface of the stay member 21 with the fixing film 22. A texture 34 (ten-point average roughness Rzjis = 50 μm) was formed.

  Specifically, the mold is first degreased and dried, and pattern transfer is performed on the transfer surface previously masked by the mold, and etching is performed to create a concavo-convex shape, followed by sand blasting and honing treatment. After adjusting the shape, the masking is removed. Then, after the mold was washed, the surface treatment in the mold was completed by performing a rust prevention treatment.

  Also, when forming a grainy pattern, degrease and dry the mold, transfer the pattern onto the masked transfer surface, create a concavo-convex shape by sandblasting, remove the masking, wash and prevent The surface treatment in the mold was completed by performing rust treatment.

  Further, when a geometric pattern such as a line or a handle is formed, a photo-etching process is used, and a desired pattern is exposed and developed on the surface of the mold using a corrosion-resistant film that reacts with light to perform masking.

  Then, an uneven shape was formed by performing an etching process, and thereafter a sand blasting process and a honing process were performed. After the uneven shape was adjusted, the surface treatment in the mold was completed by performing cleaning and rust prevention treatment.

(Slidability of fixing film and stay member)
A texture 34 is formed on the sliding surface of the stay member 21 (guide member) in this embodiment with the fixing film 22. By forming the texture 34 on the surface of the stay member 21, the contact area between the stay member 21 and the fixing film 22 is reduced, and the frictional frictional resistance between the inside of the fixing film 22 and the stay member 21 is reduced, thereby fixing the film. The rotational load of 22 can be reduced.

  Further, the lubricant does not accumulate locally due to the rotation of the fixing film 22, and always circulates stably through the gaps of the texture 34. As a result, the lubricant is immediately supplied to the entire inner surface of the fixing film 22 as the fixing film 22 starts to rotate, and the sliding frictional resistance between the fixing film 22 and the stay member 21 can be reduced.

  FIG. 4 shows the rotation time (s) and rotation torque (kg · cm) of the fixing film 22 when the fixing device 11 according to the present embodiment is used and the pressure of the pressure roller 24 is idly rotated at 10 kgf. It shows the relationship.

  Further, as a comparative example with respect to the present embodiment (ten-point average roughness Rzjis = 50 μm, (d) in FIG. 4) (a) when no grain is provided (10), ten-point average roughness Rzjis = 5 μm (b), 10 μm The results for (c) and 100 μm (e) are also shown.

  As shown in FIG. 4, with no wrinkles (a), the torque gradually decreases from the initial torque of 2.2 kg · cm, and reaches 1.9 kg · cm after 10 seconds.

  On the other hand, in the case of the present embodiment (Rzjis with wrinkles = 50 μm), the torque gradually decreases from the initial torque of 2.1 kg · cm and reaches around 1.3 kg · cm after 4 s. After that, the torque changes around 1.3 kg · cm.

Similarly, when the change in torque was measured for other comparative examples, wrinkle present Rzjis = 1
It was found that when the thickness is less than 0 μm, the torque of the fixing film 22 is not sufficiently reduced, and the fixing film 22 slips.

  In general, in an image forming apparatus, since there are many settings in which a sheet material is passed after about 5 s after starting rotation, the presence or absence of slip after 5 s was examined, and the slip generation threshold of the fixing film 22 was 1.5 kg · It was found to be about cm.

  That is, if the rotational torque of the fixing film 22 is 1.5 kg · cm or less after about 5 seconds from the start of the rotation, the fixing film 22 does not slip. On the other hand, if it is 1.5 kg · cm or more, the fixing film 22 slips.

  As a result, in the present embodiment, the 10-point average roughness Rzjis on the surface of the stay member 21 is 50 μm, but it has been found that if the surface roughness is 10 μm or more, the fixing film 22 does not slip.

  Next, FIG. 5 shows a result of comparison of gloss unevenness and fixing unevenness, slip, fixability, and cost of the present embodiment and the comparative example.

  Here, Comparative Example 1 to Comparative Example 3 are set for the present embodiment (the surface of the stay member 21 has wrinkles / Rzjis = 50 μm), and the results are shown in FIG.

  The conditions of each comparative example are as follows: comparative example 1 (no wrinkles), comparative example 2 (roughening the inner peripheral surface of the fixing film 22 and Rzjis = 50 μm), and example 3 (rotating direction of the fixing film 22 on the surface of the stay member 21) Groove formation / groove width 1.0 mm, pitch 1.0 mm, depth 0.5 mm). Further, with respect to the occurrence of gloss unevenness / fixing unevenness and slip, it was evaluated by a two-stage evaluation of no occurrence ○ and occurrence x. The evaluation of the fixability is a result of comparing the fixability in an environment of room temperature 10 ° C. and humidity 15%, and a comparison with Comparative Example 1 is described. Regarding the cost, the cost UP for the comparative example 1 is x, and the others are ◯.

  As shown in FIG. 5, Comparative Example 1 is not configured to have a texture on the surface of the stay member 21, so that the grease does not circulate well, and therefore slip occurs.

  In Comparative Example 2, since the inner peripheral surface of the fixing film 22 is roughened, the grease circulation is good, and gloss unevenness / fixing unevenness and slip do not occur. However, since the contact area between the ceramic heater 23 and the inner peripheral surface of the fixing film 22 is reduced, the thermal conductivity is deteriorated and the fixability is deteriorated.

  The fixing film 22 is formed by a process in which a polyimide resin is cast on a mold, heated to imide conversion to an intermediate stage, and then a primer layer and a release layer are formed. It is faced.

  However, when the mold is removed, the draft is approximately 0 ° with respect to the roughened surface, so that the mold removal is difficult, the yield is lowered, and the processing time is increased. As a result, the manufacturing cost increases.

  In Comparative Example 3, a groove is provided on the surface of the stay member 21, and since the grease circulation can be ensured, no slip occurs.

  Further, the fixing property does not change because the contact property between the ceramic heater 23 and the fixing film 22 does not fluctuate, and can be manufactured only by changing the structure of the mold, so the manufacturing cost does not change much.

  However, since the lubricant is circulated through the groove in the fixing film rotation direction, the surface where the lubricant and the fixing film 22 contact in the longitudinal direction of the stay member 21 and the stay member 21 are fixed in the region where the groove is formed. The thermal conductivity of the surface with which the film 22 contacts will be different. As a result, fixing unevenness and gloss unevenness occur.

  In contrast to these comparative examples 1 to 3, in the present embodiment, since the grease is circulated by the roughened surface of the stay member 21, local fixing unevenness and gloss unevenness do not occur in the longitudinal direction of the stay member 21. In addition, since the grease circulation is performed well, no slip occurs.

  Furthermore, since the contact property between the ceramic heater 23 and the fixing film 22 is also good, the fixing property is also good, and the method of making can be made by surface processing in an injection mold without increasing the manufacturing cost compared to the conventional example. Can be manufactured.

  As described above, in the image heating apparatus of the film heating system, the image heating apparatus that can reliably heat the heated member while preventing the fixing film 22 or the pressure roller 24 from slipping with a simple configuration. It becomes possible to provide.

  Further, in place of the fixing film 22 in the above configuration, the same effect can be obtained even in a configuration using a fixing sleeve formed of metal, and a configuration having an elastic layer on the fixing sleeve. Similar effects can be obtained.

  Further, a similar effect can be obtained in a magnetic induction heating type fixing device formed of a fixing sleeve and its stay member (see Japanese Patent Laid-Open No. 7-114276).

  In this embodiment, the entire surface of the stay member 21 is roughened, but only the sliding surface with the fixing film 22 may be roughened.

  Further, depending on the configuration of the mold, there may be a case where a sufficient draft is not obtained and Rzjis is not uniformly formed on the surface of the stay member 21.

  However, if at least the surface roughness of the sliding surface of the stay member 21 with the fixing film 22 can be secured, the lubricant can be stably circulated on the inner peripheral surface of the fixing film 22. Therefore, a part of the surface of the stay member 21 may be roughened, or the surface roughness may not be uniform in the rotation direction.

  Further, in the present embodiment, a textured texture is used as means for roughening the surface, but the same effect can be obtained with a sandblasting process, a grain by a honing process, or a geometric pattern by a photoetching process.

(Second Embodiment)
An image heating apparatus according to the second embodiment of the present invention will be described with reference to FIG. 6 or FIG. Here, as an embodiment of the image heating apparatus according to the present invention, a case where the image heating apparatus is applied to a fixing unit of an image forming apparatus will be described.

The present embodiment is characterized in that the area where the texture 34 is formed on the surface of the stay member 21 is narrower than the width of the fixing film 22 in contact with the stay member 21. Since other configurations are not different from those of the first embodiment, description thereof will be omitted, and only the embossed area on the surface of the stay member 21 will be described here.

  FIG. 6 shows a side view of the stay member 21 in the present embodiment. Further, FIG. 6 shows a texture forming area, a fixing film rubbing area, and a longitudinal width of the stay member 21.

  As shown in FIG. 6, the present embodiment is characterized in that the area where the texture 34 is formed on the surface of the stay member 21 is narrower than the fixing film sliding area.

  That is, since the formation area of the texture 34 has good circulation of the lubricant, if the texture formation area is formed to the outside of the film, the lubricant easily protrudes out of the fixing film sliding area. The lubricant cannot be circulated.

  Furthermore, when the lubricant protrudes, the lubricant adheres to the end portion of the sheet material, resulting in a problem that the image is stained. Further, when the lubricant adheres to the surface of the fixing film 22, the frictional force between the sheet material and the fixing film 22 is reduced, resulting in poor paper passing.

  Therefore, in the present embodiment, the wrinkle forming region is configured to be inside the fixing film rubbing region so that the grease does not leak from the end of the fixing film 22.

  FIG. 7 shows the relationship between the rotation time (h) and the rotation torque (kg · cm) of the fixing film 22 when the pressure of the pressure roller 24 is idly rotated with 10 kgf in this embodiment. is there.

  When the wrinkle forming area is longer than the fixing film rubbing area, the rotational torque increases as time passes, and slipping of the fixing film 22 occurs after idling about 80 hours.

  On the other hand, when the fixing film rubbing area is longer than the wrinkle forming area, it can be seen that the rotational torque does not increase over time and is kept substantially constant.

  That is, as in the present embodiment, on the surface of the stay member 21, the fixing film 22 is formed by forming the embossing area so that the embossing area where the embossing is formed is within the area where the fixing film 22 is rubbed. It was possible to prevent slippage.

  In the present embodiment, the wrinkle formation area is narrower than the fixing film rubbing area on the surface of the stay member 21, but the 10-point average roughness increases from the end of the stay member 21 to the center. Rzjis may be increased.

  As described above, according to the present embodiment, an image that prevents the fixing film or the pressure roller from slipping on the sheet material while reliably applying heat to the image on the sheet material with a simple configuration. A heating device can be provided.

(Other embodiments)
In the above embodiment, the case where the image heating apparatus is applied to the fixing unit of the image forming apparatus has been described. However, the embodiment of the image heating apparatus according to the present invention is not limited to this.

  For example, the image heating apparatus may be applied to a gloss applicator that applies gloss to an image by heating an image formed on a sheet material.

(A) Schematic configuration diagram of image heating apparatus according to first embodiment (b) Perspective view of stay member 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment. Schematic configuration diagram of the ceramic heater in the first embodiment Temporal change in rotational torque of fixing film in the first embodiment Comparison results of gloss unevenness / fixing unevenness, slip, fixability, and cost Side view of stay member according to second embodiment Temporal change in rotational torque of fixing film in the second embodiment

Explanation of symbols

11 Fixing device 21 Stay member (guide member)
22 Fixing film (sleeve-shaped rotating member)
23 Ceramic heater (heating member)
24 Pressure roller (Pressure member)
26 Heating resistor

Claims (9)

A sleeve-like rotating member having flexibility;
A heating member that slides with the inner peripheral surface of the rotating member;
A guide member that is provided inside the rotating member, is attached to the heating member, and slides on an inner peripheral surface of the rotating member to guide the rotation of the rotating member;
In an image heating apparatus comprising:
While the sliding surface of the guide member with the rotating member is roughened,
An image heating apparatus, wherein the sliding surface has a 10-point average roughness Rzjis of 10 μm or more. The sliding surface of the guide member with the rotating member is
The image heating apparatus according to claim 1, wherein the surface is roughened by sandblasting. The sliding surface of the guide member with the rotating member is
The image heating apparatus according to claim 1, wherein a honing process is performed to roughen the surface. The 10-point average roughness Rzjis of the sliding surface of the guide member with the rotating member is
The image heating apparatus according to claim 1, wherein the image heating apparatus increases in size from an end portion to a central portion of the guide member. The rotating member is
An endless member that fits around the heating member and the guide member;
The heat is applied to the sheet material by pressing the sheet material with a pressure member from the outside of the rotating member to a portion where the heating member and the rotating member slide. The image heating apparatus according to any one of the above. Provided inside a flexible sleeve-shaped rotating member used in the image heating device,
While sliding with the inner peripheral surface of the rotating member to guide the rotation of the rotating member,
In the guide member manufacturing method in which the heating member is attached to at least a part of the sliding surface with the rotating member,
A wall surface that forms a cavity and is molded by using a mold having a roughened portion corresponding to a sliding surface of the guide member with the rotating member. A method for producing a guide member, characterized in that the 10-point average roughness Rzjis of the sliding surface is 10 μm or more.   The method for manufacturing a guide member according to claim 6, wherein the wall surface forming the cavity of the mold is roughened by performing an etching process.   The method for manufacturing a guide member according to claim 6 or 7, wherein the wall surface forming the cavity of the mold is subjected to sandblasting to roughen the wall surface.   The method for manufacturing a guide member according to any one of claims 6 to 8, wherein the wall surface forming the cavity of the mold is roughened by performing a honing process.

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