JP2005031349A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deficiencies such as breakage of the belt and scratch on the belt by efficiently preventing a shift of a belt. <P>SOLUTION: A collar for restricting, on the heat roller, a shift of the belt supported by a peel roller and a heat roller heated by a heat source is attached to the heat roller. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device that is mounted on an image forming apparatus such as a copying machine or a printer and fixes a developer image on a sheet.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, an image forming apparatus such as an electronic copying machine has a fixing device that fixes a developer image on a sheet by heating in a pressurized state.
For example, in an electronic copying machine, a photosensitive drum is irradiated with laser light corresponding to an image signal as an image of a document read by a scanner, and an electrostatic latent image is formed on the peripheral surface of the photosensitive drum. This electrostatic latent image is visualized by the adhesion of developer (toner). The developed developer image (toner image) is transferred from the photosensitive drum to a transfer belt as an intermediate transfer member. Further, the toner image transferred to the transfer belt is transferred to a sheet that is conveyed in synchronization with the timing of the toner image on the transfer belt. In this way, the sheet on which the developer image has been transferred is further sent to the fixing device, and a fixing process is performed by the fixing device.
[0003]
A conventional fixing device includes a heating roller and a pressure roller that rotates with the heating roller while being in contact with the heating roller in a pressurized state. The sheet is sandwiched between the two rollers and conveyed while being heated. The developer image on the paper is fixed by the heat of the roller.
[0004]
In recent years, a fixing device (belt fixing device) having a belt (fixing belt) placed on a heating roller and a peeling roller has been proposed. In this type of belt fixing device, heat fixing is performed by heating in a pressed state a heating roller that is in contact with the belt in a pressurized state and a sheet on which a toner image is transferred by the pressing roller. Further, the sheet fixed in the belt fixing device is conveyed by a belt stretched along the sheet conveying path. This sheet is peeled from the belt by a peeling roller. By using the peeling roller portion as a peeling point for peeling the paper from the belt, it is possible to obtain a good image formation result without a claw mark.
[0005]
In the belt fixing device as described above, it is necessary to maintain the position of the belt hung on the heat roller and the peeling roller. In particular, since the heat roller is applied with pressure from the press roller across the belt, the belt may be displaced. If such a belt misalignment occurs, the end of the belt may be damaged and the belt may be damaged, or the belt may be damaged by the force applied to the belt by the misalignment. For this reason, in the belt fixing device, there is a demand for a technique capable of preventing damage to the belt or damage to the belt by efficiently preventing the belt from shifting.
[0006]
[Patent Document 1]
JP 2001-109285 A
[0007]
[Problems to be solved by the invention]
The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to efficiently prevent belt misalignment in a fixing device having a belt hung on a heat roller and a peeling roller. It is an object of the present invention to provide a fixing device capable of preventing problems such as breakage or damage to a belt.
[0008]
[Means for Solving the Problems]
The fixing device of the present invention fixes a developer on an image forming medium, and includes a heating roller heated by a heat source, a peeling roller disposed in the vicinity of the heating roller, the heating roller, and the peeling. A belt supported in a state of being stretched over a roller; a pressure roller that is in contact with the heating roller with a predetermined pressure across the belt; and the heating roller and the peeling roller that are installed on the heating roller And a regulating member that regulates the belt which is hung on the heating roller on the heating roller.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing an internal configuration of a composite electronic copying machine as an image forming apparatus to which the fixing device of the present invention is applied.
First, a scanner unit 11 that optically reads an image of a document O placed on a transparent document table (glass plate) for document placement is provided on the upper surface of the main body. The document image signal read by the scanner unit 11 is converted into a digital signal. The digital signal is appropriately processed and then supplied to a printer unit 12 as an image forming apparatus.
[0010]
On the other hand, a printer unit 12 that forms an image on a sheet as an image forming medium is provided below the scanner unit 11 in the main body 1. First, the image signal supplied to the printer unit 12 is supplied to the laser unit 21. The laser unit 21 irradiates the outer peripheral surface of the photosensitive drum 22 with a laser beam in accordance with an input signal as image data. The photosensitive drum 22 is rotatably provided, and an electrostatic latent image is formed on the outer peripheral surface by the laser beam emitted from the laser unit 21.
[0011]
Further, around the photosensitive drum 22, a charger 23, a black developing unit 24, a color developing unit 25, an intermediate transfer belt 26, and the like are provided. With these configurations, the electrostatic latent image formed on the photosensitive drum 22 is developed by the black developing unit 24 or the color developing unit 25 by a known process method, and the toner image is transferred to the intermediate transfer unit. It is formed on the belt 26.
[0012]
The toner image formed on the intermediate transfer belt 26 is transferred to a sheet as an image forming medium at a predetermined transfer position. The sheet on which the toner image is transferred is conveyed to a fixing device 27 which will be described in detail later. In this fixing device 27, a fixing process for fixing the toner image on the sheet to the sheet is executed, and the sheet subjected to the fixing process is discharged to the in-body discharge type discharge unit 28 by the discharge roller 29.
[0013]
Next, the fixing device 27 will be described in detail.
FIG. 2 shows a schematic configuration of a main part in the fixing device 27.
In FIG. 2, the fixing device 27 includes a heat roller (heating roller) 31, a press roller (pressure roller) 32, a belt 33, and a peeling roller 34. FIG. 3 is a diagram illustrating the configuration of the heat roller 31, the belt 33, and the peeling roller 34 in the fixing device 27.
[0014]
The heat roller 31 is rotationally driven in the direction a (right direction) by a driving motor (not shown) as a driving unit. The heat roller 31 includes a heat source. The surface of the heat roller 31 is heated to the fixing temperature by this heat source. As a heat source of the heat roller 31, an IH coil or a heating element such as a halogen lamp is used.
[0015]
For example, when an IH coil is used as a heat source for the heat roller 31, the heat roller 31 is formed by forming a conductive material, for example, iron into a cylindrical shape, and further, for example, tetrafluoroethylene resin on the outer peripheral surface of the iron. A fluororesin such as is coated. When the IH coil is used as a heat source, high frequency power is applied to the IH coil to generate a high frequency magnetic field for induction heating. When this high-frequency magnetic field is generated, an eddy current is generated in the heat roller 31, and the heat roller 31 self-heats due to Joule heat generated by the eddy current.
[0016]
A belt 33 is hung on the heat roller 31 and the peeling roller 34. The belt 33 needs to conduct heat from the heat roller 31 efficiently, and is formed of, for example, a metal such as nickel. In particular, when an IH coil is used as the heat source of the heat roller 31, the belt 33 is preferably formed of metal because heat from the heat roller 31 needs to be efficiently supplied to the belt 33.
[0017]
The peeling roller 34 is applied with a force in a direction away from the heat roller 31 by a pressure mechanism (not shown). On the other hand, the shaft of the heat roller 31 is fixed. For this reason, the belt 33 is stretched with a predetermined pressure applied to the peeling roller 34 from the pressure mechanism. That is, the force applied to the belt 33 is a force that the pressing mechanism gives the peeling roller 34 away from the heat roller 31.
[0018]
The press roller 32 is pressed against the heat roller 31 with a predetermined pressure by a pressure mechanism (not shown) with the belt 33 interposed therebetween. The surface of the press roller 32 is made of a heat-resistant elastic member such as sponge or rubber, for example. Accordingly, the press roller 32 is in pressure contact with the peripheral surface of the belt 33 at a position facing the heat roller 31. The contact portion between the press roller 32 and the belt 33 is a region where the fixing process is performed on the paper, and is configured to have a constant nip width.
[0019]
The peeling roller 34 is provided to peel off the paper as an image forming medium fixed at the nip portion between the press roller 32 and the belt 33 from the belt 33. The peeling roller 34 is configured to peel off the paper by its curved surface. Note that the paper adhered to the belt 33 without being peeled even on the curved surface of the peeling roller 34 is peeled off from the belt 33 by a peeling plate (not shown).
[0020]
In the fixing device 27 configured as described above, the sheet as the image forming medium onto which the toner image has been transferred is supplied to the nip portion between the press roller 32 and the belt 33. In the nip portion, heat from the heat roller 31 is applied to the paper on which the toner image is transferred, and the paper is pressurized with a predetermined pressure. Thereby, the toner on the sheet as the image forming medium is melted and fixed on the sheet.
[0021]
As shown in FIGS. 2 and 3, the heat roller 31 is provided with a collar (regulating member) 35 that regulates the position of the belt 33 (prevents the belt 33 from shifting). The collar 35 is made of, for example, a material such as PPS resin having heat resistance, and is formed in an annular shape.
[0022]
Hereinafter, the collar 35 and the heat roller 31 to which the collar 35 is attached will be described in detail.
FIG. 4 is a perspective view illustrating a configuration example of the heat roller 31, the belt 33, the peeling roller 34, and the collar 35. FIG. 5 is a diagram showing the relationship between the shape of the collar 35 and the shape of the heat roller 31 to which the collar 35 is attached. FIG. 6 is a perspective view showing the shape of the collar 35 in detail. FIG. 7 is a perspective view showing a configuration example as an example of a ring (fixing member) 46 for fixing the collar 35 to the heat roller 31. 8 and 9 are diagrams showing the heat roller 31 on which the collar 35 is mounted, and FIGS. 8 and 9 show the states seen from the opposite side. FIG. 10 is a cross-sectional view of the heat roller 31 with the collar 35 attached. FIG. 11 is a diagram showing the relationship between the shape of the collar 35 and the shape of the heat roller 31 corresponding to the shape of the collar 35.
[0023]
First, the shape of the heat roller 31 will be described.
As shown in FIG. 5, the heat roller 31 is provided with groove portions (concave portions) 47 at positions corresponding to the width of the belt 33 on both sides of the region where the belt 33 is applied. The collar 35 is mounted in the groove 47. That is, the interval between the groove portions 47 provided at both ends of the heat roller 31 (interval between the groove portions) is set to be at least wider than the width of the belt 33. For example, the width of the belt 33 and a predetermined margin It is set based on.
[0024]
The heat roller 31 is formed of a cylindrical member having a thickness of 0.7 mm, for example. In particular, when an IH coil is used as the heat source of the heat roller 31, the depth of the groove 47 is, for example, a depth of 0.25 mm or more with respect to the heat roller 31 having a thickness of 0.7 mm. ing. The groove 47 is formed to have a width of 2 mm or more, for example.
[0025]
Inside the heat roller 31, an IH coil or a halogen lamp is incorporated as a heat source. For this reason, the inside of the heat roller 31 preferably has a shape with no irregularities. Therefore, the depth of the groove 47 needs to be at least shallower than the thickness of the heat roller 31. Further, if the thickness of the heat roller 31 is extremely thin at the groove portion 47, the strength of the heat roller 31 itself is lowered at the groove portion 47, and there is a possibility that the heat roller 31 is damaged or deformed. is there. On the other hand, in order to hold the collar 35, it is advantageous that the depth of the groove 47 is as deep as possible.
[0026]
For the reasons described above, the depth of the groove 47 is set to a range that does not affect at least the strength of the heat roller 31 itself, and can reliably hold the collar 35. For example, when the thickness of the heat roller 31 is 0.7 mm, the thickness of the heat roller 31 in the groove 47 is formed to be 0.4 mm or more. Moreover, when the above-mentioned conditions are added, the depth of the groove portion 47 is suitably 0.25 mm to 0.3 mm for the 0.7 mm heat roller 31.
[0027]
Next, the shape of the collar 35 will be described in detail.
The collar 35 is composed of a member 41 in which a material such as PPS is formed in an annular shape. The collar 35 is provided with a slit 42 as shown in FIGS. Further, as shown in FIGS. 5 and 6, the collar 35 has a two-stage inner shape, and is a portion that is on the belt 33 side when mounted on the heat roller 31 (this portion is a convex portion 43. Called) is raised inside the ring. Further, a groove 44 having a protrusion 45 is provided on the outer peripheral surface of the collar 35.
[0028]
The slit 42 is provided to temporarily widen the inner diameter of the collar 35 when the collar 35 is attached to the heat roller 31. The slit 42 is designed to have a predetermined width when the collar 35 is attached to the heat roller 31. The slit 42 will be described in detail later.
[0029]
The convex portion 43 is a portion fitted into a groove portion 47 provided on the surface of the heat roller 31. That is, the height of the convex portion 43 is designed corresponding to the depth of the groove portion 47 of the heat roller 31. Further, the width of the convex portion 43 is also designed corresponding to the width of the groove portion 47 of the heat roller 31.
[0030]
A ring (fixing member) 46 is attached to the groove 44. The ring 46 has an annular shape and a part thereof is opened. The ring 46 is formed of, for example, a C ring as shown in FIG. The ring 46 is a fixing member that fixes the collar 35 on the heat roller 31. Specifically, after the convex portion 43 of the collar 35 is attached to the groove portion 47 of the heat roller 31, the ring 46 is attached to the groove portion 44.
[0031]
As a result, the entire collar 35 is clamped by the ring 46 and fixed on the heat roller 31. Further, when the ring 46 is mounted in the groove 44, the ring 46 is mounted so that the open portion of the ring 46 matches the protrusion 45 provided in the groove 44. That is, the fixing member 46 is mounted in the groove portion 44 of the collar 35 as shown in FIG.
[0032]
As described above, a collar for regulating the deviation of the belt supported on the heat roller heated by the heat source and the peeling roller on the heat roller is mounted on the heat roller. Yes. As a result, it is possible to efficiently prevent the belt from shifting and to prevent problems such as damage to the belt and damage to the belt.
[0033]
In addition, as described above, the collar that regulates the position of the end of the belt is attached to the heat roller so as to prevent the belt from shifting on the heat roller, so that the belt can be effectively prevented from shifting. For example, if a member for regulating the belt deviation is provided on the peeling roller, the belt deviation may not be efficiently regulated when the belt deviation occurs on the heat roller.
[0034]
In other words, since pressure is applied to the heat roller from the press roller across the belt, even if the deviation of the belt is regulated at the peeling roller portion, the deviation on the heat roller may not be efficiently regulated. This is because there is sex.
Therefore, by restricting the positions of both ends of the belt on the heat roller by the collar attached to the heat roller to which pressure from the press roller is applied across the belt, the effect of effectively preventing the belt from shifting can be obtained. is there.
[0035]
Next, the relationship between the position of the protrusion 45 and the ring 46 will be described mainly with reference to FIGS. 5, 6, and 7.
As shown in FIGS. 5 and 6, the protrusion 45 is provided at a position facing the slit 42. As described above, the ring 46 is fitted in the groove portion 44 provided outside the collar 35, but when the open portion of the ring 46 is in the same position as the slit 42 of the collar 35. The possibility that the ring 46 widens the slit 42 of the collar 35 is increased. If the slit 42 is widened, the inner diameter of the collar 35 is widened, so that the convex portion 43 of the collar 35 may come off from the groove portion 47 of the heat roller 31 and cause damage to the belt 33 and the like.
[0036]
That is, the collar 35 is prevented from being detached from the heat roller 31 by preventing the open portion of the ring 46 from being aligned with the position of the slit 42. In the present embodiment, the open portion of the ring 46 is held by the protrusion 45 provided in the groove portion 44 of the collar 35 so that the open portion of the ring 46 does not become the position of the slit 42. As a result, problems such as belt breakage are prevented.
[0037]
In the example shown in FIGS. 5 and 6, the protrusion 45 is provided at a position facing the slit 42, but the position where the protrusion 45 is installed is such that the open portion of the ring 46 is located on the slit 42. Any position may be used as long as the position is held so as not to be in the position. If the protrusion 45 is provided at a position facing the slit 42, the opening portion of the ring 46 and the slit 42 of the collar 35 face each other. The effect of suppressing is great.
[0038]
Next, the shape of the slit 42 of the collar 35 will be described in detail mainly with reference to FIGS.
As shown in FIGS. 8 and 9, the collar 35 may come into contact with the end portion of the belt 33 in a state where the collar 35 is attached to the heat roller 31. For this reason, the slit 42 has a structure in which the end portion of the belt 33 is not damaged by the edge portion 51 of the slit 42 when the inner surface of the collar 35 contacts the end portion of the belt 33. There is a need.
[0039]
In order to satisfy such a condition, it is effective that the edge portion 51 of the slit 42 of the collar 35 is rounded (R is added). For example, the roundness of the edge portion 51 is about R0.1 to R0.5. Thereby, even if the end portion of the belt 33 contacts the edge portion 51 of the slit 42, the belt 33 is not damaged, and problems such as breakage of the belt 33 can be prevented.
[0040]
Further, in order to prevent the edge portion 51 of the slit 42 from scratching the end portion of the belt 33, the width of the slit 42 is made as small as possible so that the end portion of the belt 33 contacts the edge portion 51 of the slit 42. It may be difficult to do. In this case, for example, the width of the slit 42 needs to be within a predetermined range in a state where the heat roller 31 has reached the fixing temperature. When the heat roller 31 is at the fixing temperature, the heat roller 31 and the collar 35 are thermally expanded, so that the width of the slit 42 changes from that at room temperature.
[0041]
Therefore, in order to reduce the width of the slit 42 so that the end portion of the belt 33 does not easily hit the edge portion 51 of the slit 42, the width of the slit 42 is changed while the heat roller 31 has reached the fixing temperature. Set within a predetermined range. For example, the width of the slit 42 is set to be 2 mm or less when the heat roller 31 reaches the fixing temperature.
[0042]
Even if the heat roller 31 reaches the fixing temperature, the slit 42 needs to be opened. That is, when the heat roller 31 reaches the fixing temperature and the slit 42 is completely closed, the inner diameter of the collar 35 is deformed or the inner diameter of the collar 35 is further expanded upon thermal expansion. This is because there is a possibility that the collar 35 is detached from the heat roller 31 because the diameter becomes larger than the outer diameter of the heat roller 31.
[0043]
In order to satisfy such a condition, the slit 42 of the collar 35 needs to be open at least when the heat roller 31 reaches the fixing temperature or when the fixing temperature + the predetermined temperature. By satisfying such a condition, it is possible to prevent a problem that the color 35 is deformed or the color roller 35 is detached from the heat roller 31 during the fixing process.
[0044]
In addition, if the condition of the width of the slit 42 that prevents the edge portion 51 of the slit 42 from scratching the end portion of the belt 33 is added to such a condition, the width of the slit 42 is determined by the heat roller 31. In a state where the fixing temperature has been reached, or in a state where the fixing temperature + a predetermined temperature has been reached, it is necessary to be within a predetermined range and open. By designing the width of the slit 42 so as to satisfy such a condition, the collar 35 is deformed or detached from the heat roller 31 without damaging the end of the belt 33 during the fixing process. You can prevent problems.
[0045]
Further, in the configuration as shown in FIG. 8, it is necessary to remove the ring 46 and remove the collar 35 itself from the heat roller 31 when parts are replaced (when the collar 35 is replaced). That is, when parts are replaced, a force for removing the ring 46 from the collar 35 must be applied to the ring 46 while the collar 35 is mounted.
[0046]
In the configuration shown in FIG. 8, when a tool such as a flat-blade screwdriver is inserted into the slit 42 and a force is applied to the ring 46, the ring 46 can be removed efficiently. Normally, parts replacement is performed in a state where the heat roller 31 is not heated, that is, in a state where the heat roller 31 and the collar 35 are at a normal temperature (or a temperature that is safe for humans to touch (normal temperature + 50 ° C.)).
[0047]
Accordingly, in order to improve the efficiency of the parts replacement operation such as the replacement of the collar 35 as described above, the slit 42 of the collar 35 can be inserted with an instrument such as a flat-blade screwdriver at a temperature from room temperature to room temperature + 50 ° C. The width is preferred. For example, when the temperature is from room temperature to room temperature + 50 ° C., the width of the slit 42 into which an instrument such as a flathead screwdriver can be inserted may be 1 mm or more.
[0048]
The ring 46 is preferably attached to the collar 35 smoothly when the collar 35 is attached to the heat roller 31. In particular, when the ring 46 is attached to the collar 35, if the edge of the groove portion 44 of the collar 35 or the edge of the open portion of the ring 46 is sharp, it is difficult to attach the ring 46 to the collar 35, or There is a possibility of scratching.
[0049]
Accordingly, the edge of the groove portion 44 of the collar 35 may be rounded, the edge of the open portion of the ring 46 may be rounded, or the edge of the open portion of the ring 46 may not be in contact with the collar 35. For example, in the example of the shape of the ring 46 shown in FIG. 7, the open portion of the ring 46 does not contact the collar 35. By adopting such a shape, it is possible to facilitate the attachment of the ring 46 to the collar 35 without damaging the collar 35, and the efficiency in attaching the collar 35 to the heat roller 31 can be improved. Can be improved.
[0050]
Next, a configuration example of the shape of the heat roller 31 and the shape of the collar 35 will be described in detail mainly with reference to FIG.
As shown in FIG. 10, the heat roller 31 and the collar 35 are configured such that a groove portion 47 of the heat roller 31 and a convex portion 43 provided inside the collar 35 are combined. The end portion of the belt 33 may come into contact with the surface of the collar 35 thus configured on the belt 33 side (hereinafter referred to as a contact surface with the belt). In particular, it is desirable to reduce the friction between the contact surface of the collar 35 with the belt and the end of the belt 33 as much as possible under the condition that the process speed exceeds 200 mm / sec.
[0051]
This is because if the end portion of the belt 33 due to contact with the collar 35 is severely worn, the life of the belt 33 is shortened. Therefore, as described above, the material of the collar 35 is formed of PPS. Further, as shown in FIG. 10, the coating 52 for reducing the friction with the belt 33 on the contact surface of the collar 35 with the belt. Has been given.
[0052]
As the coating 52, for example, a fluorine resin such as a tetrafluoroethylene resin or the like may be coated, or a UV coating may be applied. In this way, by applying the coating process to the contact surface of the collar 35 with the belt, it is possible to prevent the wear of the end of the belt 33 due to the contact with the collar 35 and to improve the liveness of the belt 33. Become.
[0053]
Next, the shape of the contact surface of the collar 35 with the belt will be described in detail mainly with reference to FIG.
As shown in FIG. 11, the contact surface of the collar 35 with the belt is composed of a parallel portion and an inclined portion. The parallel portion is a portion that is parallel to the end surface of the belt 33. The thickness b of the parallel portion is designed to be less than twice the thickness a of the belt 33. The parallel portion is a portion that contacts the end portion of the belt 33. Further, at the contact surface with the color belt, the end surface of the belt 33 is held by the parallel portion. That is, the end surface of the belt 33 is mainly in contact with the parallel portion.
[0054]
For this reason, the larger the thickness d of the parallel part, the larger the area (contact area) in contact with the end face of the belt 33 and the end face of the belt 33 and the flat part come into contact with each other. Time (contact time) also becomes longer. As a result, the contact between the belt 33 and the collar 35 increases, and wear of the end portion of the belt 33 increases. On the other hand, the smaller the thickness d of the parallel portion, the higher the probability that the end portion of the belt 33 contacts the inclined portion. When the end portion of the belt 33 comes into contact with the inclined portion, a larger force is applied to the end portion of the belt 33 than to contact the parallel portion.
[0055]
For these reasons, it is preferable that the parallel portion reliably supports the end surface of the belt 33 and reduces friction with the end surface of the belt 33. Therefore, in the present embodiment, the thickness d of the parallel portion is set to be not less than the thickness a of the belt 33 and not more than twice the thickness a of the belt 33. For example, when the belt 33 has a thickness of 0.3 mm, the parallel portion has a thickness of 0.3 mm to 0.6 mm. By setting the thickness of the parallel part of the collar to be equal to or greater than the thickness of the belt and within twice the thickness of the belt as described above, the belt end can be securely held and the belt end can be worn. The belt life can be improved.
[0056]
Next, the relationship between the groove portion 47 of the heat roller 31 and the convex portion 43 of the collar 35 will be described in detail mainly with reference to FIG.
It is necessary to fit the convex portion 43 of the collar 35 into the groove portion 47 of the heat roller 31. For this reason, as shown in FIG. 11, the width c of the convex portion 43 of the collar 35 is at least smaller than the width d of the groove portion 47 of the heat roller 31. However, if the width of the groove portion 47 of the heat roller 31 is made too large with respect to the width c of the convex portion of the collar 35, the collar 35 is displaced and the belt 33 is damaged by the step of the groove portion 47 of the heat roller 31. there is a possibility. If the belt 33 is damaged, there is a possibility that problems such as breakage of the belt 33 occur.
[0057]
Therefore, the width of the groove portion 47 of the heat roller 31 is equal to or larger than the width of the convex portion 43 of the collar 35 and the contact surface between the groove portion 47 and the belt of the collar 35 even when the collar 35 is displaced. It is necessary to design the belt 33 so that the belt 33 is not damaged by the step. For example, the width d of the groove portion 47 of the heat roller 31 is larger than the width c of the convex portion 43 of the collar 35 and not more than 0.5 mm wider than the width c of the convex portion 43 of the collar 35. . That is, it is designed so that c <d <c + 0.5.
[0058]
As described above, the width of the groove portion of the heat roller is not made larger than the width of the convex portion of the collar by a predetermined range, so that the belt is not damaged even when the collar is displaced, It becomes possible to improve the life of the belt.
[0059]
Next, the relationship between the groove portion 44 of the collar 35 and the ring 46 will be described mainly with reference to FIG.
It is necessary to fit the ring 46 into the groove portion 44 of the collar 35. For this reason, as shown in FIG. 11, the width e of the annular member of the ring 46 is at least smaller than the width f of the groove portion 44 of the collar 35. However, if the width of the groove portion 44 of the collar 35 is made too large with respect to the width e of the ring 46, the ring 46 is displaced in the groove portion 44 and it becomes difficult to securely fix the collar 35. If the collar 35 is not securely fixed, the belt 33 may be damaged.
[0060]
Accordingly, the width f of the groove portion 44 of the collar 35 is equal to or larger than the width e of the ring 46 and the collar 35 is securely fixed to the heat roller 31 even when the ring 46 is displaced in the groove portion 44. You must design to the extent you want. For example, the width f of the groove portion 44 of the collar 35 is set to be larger than the width e of the ring 46 and not to be wider than 0.5 mm than the width e of the ring 46. That is, it is designed so that e <f <e + 0.5.
[0061]
As described above, by preventing the groove provided outside the collar from being wider than the ring by a predetermined range or more, the collar can be securely fixed to the heat roller, and the belt can be damaged. You can prevent problems.
[0062]
【The invention's effect】
As described above in detail, according to the present invention, in the fixing device having the belt hung on the heat roller and the peeling roller, the belt is damaged or the belt is damaged by efficiently preventing the belt from shifting. Can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus having a fixing device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a configuration of a main part in the fixing device according to the embodiment of the present invention.
FIG. 3 is a perspective view illustrating a configuration example of a heat roller, a belt, a peeling roller, and a collar.
FIG. 4 is a perspective view illustrating a configuration example of a heat roller, a belt, a peeling roller, and a collar.
FIG. 5 is a diagram showing a relationship between the shape of a collar and the shape of a heat roller on which the collar is mounted.
FIG. 6 is a perspective view showing the shape of a collar in detail.
FIG. 7 is a perspective view showing a configuration example of a ring as a fixing member attached to a collar.
FIG. 8 is a view showing a heat roller on which a collar is mounted.
FIG. 9 is a view showing a heat roller on which a collar is mounted.
FIG. 10 is a cross-sectional view of a heat roller with a collar mounted thereon.
FIG. 11 is a diagram illustrating a relationship between a color shape and a heat roller shape corresponding to the color shape;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 12 ... Printer part, 27 ... Fixing device, 28 ... Paper discharge part, 29 ... Paper discharge roller, 31 ... Heat roller, 32 ... Press roller, 33 ... Belt, 34 ... Release roller, 35 ... Release plate, 36a, 36b ... Conveying guide, 42 ... slit, 43 ... convex part, 44 ... groove part, 45 ... projection part, 46 ... ring, 47 ... groove part

Claims (12)

A fixing device for fixing a developer on an image forming medium,
A heating roller heated by a heat source;
A peeling roller disposed in the vicinity of the heating roller;
A belt supported in a state of being stretched over the heating roller and the peeling roller;
A pressure roller in contact with the heating roller with a predetermined pressure across the belt;
A regulating member that is installed on the heating roller and regulates on the heating roller a belt that is hung on the heating roller and the peeling roller;
A fixing device. A groove is provided on the surface of the heating roller,
The fixing device according to claim 1, wherein the regulating member is provided with a convex portion that fits in a groove of the heating roller. The fixing device according to claim 1, wherein the regulating member is formed of an annular member having a slit. The fixing device according to claim 1, wherein the regulating member is fixed to the heating roller by an annular fixing member. The regulating member is fixed to the heating roller by a fixing member made of an annular member having an open portion,
The fixing device according to claim 1, wherein the restricting member is provided with a protrusion that holds a position of the opening of the fixing member. 2. The fixing device according to claim 1, wherein at least an edge portion of the slit provided on the regulating member on the belt side surface is rounded. 3. The fixing according to claim 1, wherein the slit of the regulating member attached to the heating roller is opened within a predetermined width in a state where the heating roller reaches a fixing temperature. apparatus. The fixing device according to claim 1, wherein the slit of the regulating member attached to the heating roller is opened with a predetermined width or more when the heating roller is in a room temperature state. The regulating member is fixed to the heating roller with a fixing member made of an annular member having an open portion,
The fixing device according to claim 1, wherein an end portion of the opening portion of the fixing member has a rounded shape or a shape that does not contact the regulating member. The fixing device according to claim 1, wherein the regulating member is provided with a coating that reduces friction with the belt on a surface that contacts the belt in a state where the heating roller is fixed. . The regulating member has a contact surface parallel to the end surface of the belt in a state where the heating roller is fixed, and the thickness of the contact surface is equal to or greater than the thickness of the belt and the thickness of the belt. The fixing device according to claim 1, wherein the fixing device is within twice. The fixing device according to claim 2, wherein a width of the groove provided on the surface of the heating roller is not wider than a predetermined range than a width of the convex portion provided on the regulating member.

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