JP7338389B2 - Fixing device and image forming device - Google Patents

Description

The present invention relates to fixing devices and image forming apparatuses.

In the fixing belt type fixing device of an electrophotographic image forming apparatus, when a large number of sheets of the same size are passed through, the fixing belt is damaged at the edge of the paper, and glossy streaks occur in subsequent feeding of the paper. Uneven gloss may occur due to deterioration of the surface properties of the fixing belt. Therefore, in order to repair scratches on the surface of the fixing belt, there is a technique of mounting a refreshing roller for polishing the surface of the fixing belt and polishing the surface of the fixing roller.

For example, Japanese Patent Application Laid-Open No. 2002-200003 discloses a technique of bringing a refreshing roller, which is a rotating body, into contact with the fixing member as a rubbing member in order to solve problems caused by the generation of scratches, unevenness, and dirt on the surface of the fixing member. there is

However, in a fixing device equipped with a refreshing roller as in Patent Document 1, there is a problem that it is difficult to simultaneously prevent an increase in driving torque and a decrease in refreshing performance.

An object of one aspect of the present invention is to provide a fixing device capable of suppressing both an increase in drive torque and a decrease in refresh performance.

A fixing device according to the present invention includes a fixing surface modifying member that modifies the surface of the fixing member that is rotationally driven, a detection means that detects the speed of the fixing member, and drive control that rotates the fixing surface modifying member. a mechanism, wherein the fixing surface modifying member rotates at a linear speed ratio with respect to the fixing member ; Control is performed to change the linear velocity ratio so that the polishing performance of the fixing surface modifying member exceeds a predetermined reference value and the driving torque of the fixing surface modifying member is less than the predetermined reference value. It is configured as a fixing device that

According to the present invention, it is possible to achieve both suppression of drive torque increase and suppression of deterioration of refresh performance.

1 is an explanatory diagram of a schematic configuration of a printer according to one embodiment; FIG. FIG. 2 is an explanatory diagram of a configuration example of two belt heating type fixing devices that can be preferably provided in a printer according to an embodiment; Explanatory drawing of a rotation detection member. FIG. 4 is a functional explanatory view of a refresh roller mechanism of the fixing device shown in FIG. 3; FIG. 5 is a diagram showing an example of linear speed ratio between a fixing roller and a refreshing roller; FIG. 5 is a diagram showing the relationship between the linear velocity ratio between the fixing roller and the refreshing roller during thermal expansion and the refreshing performance; FIG. 5 is a diagram showing the relationship between the linear velocity ratio between the fixing roller and the refreshing roller during thermal expansion and the torque of the driving motor that drives the refreshing roller;

Embodiments of a fixing device and an image forming apparatus will be described in detail below with reference to the accompanying drawings. In this embodiment, the rotation speed of the heating roller is detected to detect the speed of the fixing roller, and the rotation speed of the refreshing roller is changed according to the detection result. When the speed of the fixing roller is slow, the rotational speed of the refreshing roller is increased, and when the speed of the fixing roller is fast, the rotational speed of the refreshing roller is decreased. This suppresses the increase in driving torque of the refreshing roller and improves the polishing performance of the refreshing roller. compatible.

That is, when the thermal expansion of the fixing roller is large, the rotational speed of the fixing roller increases and the contact pressure of the refreshing roller is strong, so the drive torque is large and the polishing performance is high, so the rotational speed of the refreshing roller is reduced. When the thermal expansion of the fixing roller is small, the rotation speed of the fixing roller becomes slow and the contact pressure of the refreshing roller is weak. By performing such control, it is characterized in that it is possible to suppress an increase in the drive torque of the refreshing roller and achieve both the polishing performance of the refreshing roller. The features of the invention described above will be explained in detail with reference to the following drawings.

An embodiment of an electrophotographic tandem color printer (hereinafter referred to as printer 200) will be described below as an image forming apparatus equipped with a fixing device to which the present invention is applied. FIG. 1 is a schematic configuration explanatory diagram of a printer 200 according to this embodiment.

As shown in FIG. 1, the printer 200 is a high-speed machine that includes an image forming section 200A located in the upper part of the apparatus main body, and a paper feeding section 200B located below the image forming section 200A. A fixing device 100 is incorporated.

In the image forming section 200A, an intermediate transfer belt 210 is arranged at the center of the apparatus main body in the vertical direction. A configuration is provided for forming a Specifically, as an image carrier (latent image carrier) capable of carrying toner images of yellow (Y), magenta (M), cyan (C), and black (K), which are complementary colors, are arranged side by side along the upper transfer surface of the intermediate transfer belt 210 .

The photoreceptors 205Y, M, C, and K are drum-shaped and rotatable in the same direction (counterclockwise direction in the drawing). Charging devices 202Y, M, C, and K; developing devices 203Y, M, C, and K; primary transfer devices 204Y, M, C, and K; , C, K, etc. are arranged.

The developing devices 203Y, 203M, 203C, and 203K contain respective color toners. Optical writing devices 201Y and 201M and optical writing devices 201C and K are arranged at the uppermost part of the image forming section 200A.

Intermediate transfer belt 210 has a configuration in which intermediate transfer belt 210 is wound around a drive roller and a driven roller and is movable in the same direction at positions facing photoreceptors 205Y, M, C, and K. As shown in FIG.

A secondary transfer roller 212 is provided at a position facing a secondary transfer counter roller 211, which is one of the driven rollers.

Further, the conveying path of the paper P as the recording material (sheet) from the secondary transfer roller 212 to the fixing device 100 is a lateral path in a substantially horizontal direction.

The paper feed unit 200B separates the paper feed tray 220 for stacking and containing the paper P, and the paper P in the paper feed tray one by one from the bottom, and conveys them to the position of the secondary transfer roller 212. It has a transport mechanism.

During image formation in the printer 200, the surface of the photoreceptor 205Y is uniformly charged by the charging device 202Y, and an electrostatic latent image is formed on the photoreceptor 205Y based on image information from the image reading section. The formed electrostatic latent image is visualized as a toner image by a developing device 203Y containing yellow (Y) toner. Primary transfer is performed on the top.

Similar images are formed on the other photoreceptors 205M, 205C, and 205K with different toner colors, and the toner images of the respective colors are sequentially transferred onto the intermediate transfer belt 210 by electrostatic force and superimposed.

Next, the toner images primarily transferred onto the intermediate transfer belt 210 from the photoreceptors 205Y, M, C, and K are transferred onto the conveyed paper P by the secondary transfer facing roller 211 and the secondary transfer roller 212. . The paper P onto which the toner image has been transferred is further conveyed to the fixing device 100, fixed at the fixing nip portion N between the fixing belt 51 and the pressure roller 55, and discharged to the exit side of the fixing nip portion N. . Then, the paper P ejected from the fixing nip portion N is delivered to the stacker 215 along the ejection path.

In addition, transfer residual toner and the like remaining on the photoreceptors 205Y, M, C, and K without being primarily transferred onto the intermediate transfer belt 210 are removed by the photoreceptor cleaning devices 206Y, M, C, and K, respectively. In addition, transfer residual toner or the like remaining on the intermediate transfer belt 210 without being secondarily transferred onto the paper P is removed by the belt cleaning device 213 to prepare for the next image formation.

Next, examples of two belt heating type fixing devices 100 that can be preferably provided in the printer 200 of the present embodiment will be described with reference to the drawings.

FIGS. 2A and 2B are explanatory diagrams of configuration examples of two belt-heating type fixing devices that can be preferably provided in the printer 200 of the present embodiment. FIG. 5 is an explanatory diagram of an example in which a heater 53a such as a halogen heater is provided inside a heating roller 54; FIG. FIG. 2B is an explanatory view of an example in which an induction heating means 53b is provided as a heating means for the heating roller 54 so as to face the outer peripheral portion of the fixing belt 51 that is stretched around the heating roller 54. As shown in FIG.

Since the configuration example shown in FIG. 2A and the fixing device 100 of the configuration example shown in FIG. The description will focus on the configuration common to

The fixing device 100 shown in FIGS. 2A and 2B (hereinafter referred to as FIG. 2 as appropriate) has a fixing roller 52, a heating roller 54, a fixing belt 51, and a pressure roller 52 inside a fixing cover 100a. A roller 55 is provided. Then, the pressure roller 55 is pressed against the fixing roller 52 with the fixing belt 51 interposed therebetween, and a fixing nip portion N is formed between the fixing belt 51 and the pressure roller 55 .

A fixing separation member 57 and a pressure separation member 58 are provided on the paper P ejection side of the fixing nip portion N. As shown in FIG.

The fixing roller 52 has an elastic rubber layer 52b made of silicon rubber or the like on a metal core 52a. Here, as the material of the elastic rubber layer 52b, foamed silicon rubber can be used so as not to absorb the heat of the fixing belt 51 easily in order to shorten the warm-up time.

The heating roller 54 is a hollow roller made of stainless steel or nickel alloy, and in the configuration example shown in FIG. On the other hand, in the configuration example shown in FIG. 2A, an induction heating means 53b, which is a heating means of an IH system using electromagnetic induction, is provided facing the outer peripheral portion of the fixing belt 51 that is stretched around the heating roller 54. be done.

The fixing belt 51 is an endless belt, and has a cross-sectional structure of, for example, a two-layer structure in which an elastic layer such as a silicon rubber layer is formed on a base material such as polyimide.

The fixing belt 51 is stretched over the fixing belt 51 and the heating roller 54 with a constant tension by a heating roller tension spring fixed to the heating roller 54 and the fixing frame.

The pressure roller 55 is a hollow roller made of aluminum, iron, or the like, and is provided with a heater 53a, which is a heating means using a halogen heater. It is a cylindrical roller.

Further, the pressure roller 55 is in a pressurized state in which the pressure is applied to the fixing belt 51 side and a depressurized state (separated state) in which the pressure is released by separating from the fixing belt 51 by the following pressurizing and depressurizing means 80 . and is configured to be switchable.

As shown in FIG. 2, the pressure release means 80 has a pressure lever 81, a pressure spring 82, a pressure cam 83, and a pressure camshaft 84, and the pressure camshaft 84 is rotated by a drive motor. Thus, it is configured to be switchable between the pressurized state and the depressurized state. Specifically, by rotating the pressure camshaft 84 , the pressure roller 55 is moved toward the fixing belt 51 to apply pressure, and the pressure roller 55 is moved away from the fixing belt 51 to separate it. It is possible to release the pressure by

A predetermined nip pressure can also be obtained by adjusting the cam position of the pressurizing cam 83 by means of the drive motor using the pressurizing and depressurizing means 80 .

When the fixing device 100 is driven, for example, the fixing belt 51 is rotated in the direction in which the paper P is ejected by rotating the fixing roller 52 clockwise in FIG. Roller 55 rolls along. Here, the roller to be rotationally driven is not limited to the fixing roller 52 and may be the pressure roller 55 .

During the fixing operation, in the example shown in FIG. 2A , the heating roller 54 is first heated by a heater 53 a provided inside the heating roller 54 and the heat is transferred to the fixing belt 51 . The heating roller 54 is heated until the temperature detected by the thermopile 56 of the fixing belt 51 reaches a predetermined temperature (for example, a temperature suitable for toner fixing).

On the other hand, in the example shown in FIG. 2B, first, the heating roller 54 is heated by the electromagnetic induction of the induction heating means 53 provided outside the heating roller 54 and the heat is transferred to the fixing belt 51 . The heating roller 54 is heated until the temperature of the fixing belt 51 detected by the thermopile 56 reaches a predetermined temperature.

Also, the pressure roller 55 is also heated to a predetermined temperature by the heat generated by the pressure heater 59 arranged inside when necessary, such as when the temperature is raised. Here, in this embodiment, an example of using the roller-type pressure roller 55 as the pressure member is shown, but the present invention is not limited to this, and an endless belt stretched over two rollers is used. A belt-type pressure member may be used.

In the fixing device 100, the surface of the fixing belt 51 is heated to a predetermined temperature while the fixing belt 51 and the pressure roller 55 are driven to rotate. ) is transported (passed). Then, the unfixed toner image T is fixed on the paper P by pressure and heat in the fixing nip N. As shown in FIG.

At this time, since the paper P may come out while being wrapped around the fixing belt 51 , it is separated by the fixing separation member 57 . Further, the paper P wound around the pressure roller 55 and discharged is separated by the pressure separating member 58 and conveyed along the conveying guide.

In the fixing device 100 , the heating roller 54 is heated to a predetermined temperature, and the paper P is fed (conveyed) to the fixing nip N after paper feeding is permitted in the fixing device 100 .

However, in the case of a paper-passing job in which the paper P is continuously passed, the heat roller 54 is continuously heated in order to compensate for the amount of heat taken away from the fixing nip N by the paper P.

The fixing belt 51 stretched between the heating roller 54 and the fixing roller 52 conveys heat to the fixing nip N to fix the toner onto the paper P. At the same time, the fixing roller 52 is also continuously heated.

Due to thermal expansion, the fixing roller 52, which is continuously heated by the continuous feeding of paper, has an outer diameter larger than that when paper feeding is permitted, and the moving speed (peripheral speed, linear speed) of the fixing belt 51 increases ( faster). The thermal expansion of the fixing roller 52 is largely due to the thermal expansion coefficient of silicone rubber (representative value of thermal expansion coefficient of silicone rubber: 3.0×10E−4/° C.). Therefore, the amount of expansion is roughly determined by the amount of heat given per unit time and the set temperature, and accordingly the moving speed of the fixing belt 51, that is, the speed of the paper P conveyed through the fixing nip N changes.

Although such an increase in the moving speed of the fixing belt 51 is less than that in the configuration in which the fixing roller 52 is rotationally driven, it occurs for the same reason in the configuration in which the pressure roller 55 is rotationally driven. thermal expansion increases the moving speed of the fixing belt 51 .

For these reasons, in order to keep the transport speed of the paper P transported through the fixing nip N at a predetermined speed, the rotation speed of the heating roller 54 rotating at substantially the same speed as the moving speed of the fixing belt 51 is detected. , fuser roller 52 or pressure roller 55 is preferably controlled. That is, even if the radius (outer diameter) of the rotationally driven fixing roller 52 or pressure roller 55 changes due to thermal deformation such as thermal expansion or aging, the moving speed of the fixing belt 51 wound around the heating roller 54 remains unchanged. , that is, the conveying speed of the recording material can be detected with high accuracy.

Further, as described below, the rotation speed of the heating roller 54 is detected, and when the rotation speed reaches a predetermined value, for example, the controller 1000 of the printer 200 shown in FIG. If a control unit is provided, the control unit detects that thermal expansion has occurred in the fixing roller 52 or the pressure roller 55, that is, if the rotational speed of the heating roller 54 exceeds the threshold value, the fixing It is also possible to determine that the roller 52 or the pressure roller 55 is in a relationship in which thermal expansion occurs, and control the refresh roller, which will be described later, on the assumption that the thermal expansion of the fixing roller 52 or the pressure roller 55 is detected.

The control unit 1000 can use, for example, general hardware configured by an arithmetic device having a processor such as a CPU (Central Processing Unit), and the control is performed by the arithmetic device executing a program. done. It should be noted that the main body of processing performed by executing the program may be an arithmetic unit, and includes a dedicated circuit (for example, FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit)) that performs specific processing. good too.

Next, a configuration example of the rotation detection member 63 provided for detecting the rotation speed of the heat roller 54, which can be suitably provided in the fixing device 100 of the present embodiment, will be described with reference to the drawings.

FIG. 3 is an explanatory diagram of the rotation detection member 63 according to this configuration example, showing a cross section perpendicular to the longitudinal direction of the fixing roller 52 .

Here, FIG. 3 shows an example in which a heater 53 a is used as the heating means for the heating roller 54 .

The rotation detecting member 63 shown in FIG. 3 is provided with a rotating filler 63f as a member to be detected on the rotating shaft of a rotation transmitting means 62 as a rotating body that rotates by transmitting a rotational force from the heating roller 54. This is detected by the photosensor 63b.

Specifically, at one end in the longitudinal direction of the heating roller 54, there is provided a heating roller as a first rotation transmission means such as a gear that is shaped to support the heating roller 54 and transmits the rotational force of the heating roller 54 to its outer peripheral surface. A roller rotation transmission means 61 is provided. In addition, a rotation-receiving transmission means 62 as a second rotation-receiving transmission means having a gear or the like that meshes with the heating roller rotation-transmitting means 61 is arranged to face the heating roller rotation-transmitting means 61 .

Further, the rotation transmission means 62 is pressed against the heating roller rotation transmission means 61 by a rotation transmission means urging member 72 such as a tension coil spring (see FIG. 2(b)).

With the above-described configuration, the rotational speed of the rotation transmitting means 62 rotating at a higher rotational speed than that of the heating roller 54 is detected using the rotation detecting member 63, and the heating roller 54, and thus the fixing belt 51 and the paper P are detected. It is possible to detect the moving speed (rotating state) of

By detecting in this way, compared to a configuration in which the rotation speed of the heating roller 54 itself is directly detected using the rotation detection member 63, the moving speed of the heating roller 54, and thus the fixing belt 51 and the paper P, can be obtained with higher accuracy. can be detected.

The rotation detecting member 63 is a member to be detected having four fillers, and is a rotating filler 63f and a photo sensor as a detecting member for detecting light shielding/light passing by each filler of the rotating filler 63f. 63b.

The rotating filler 63f shown in FIG. 3 rotates at an accelerated speed while synchronizing with the heating roller 54, so that it is fast enough to be read by an ordinary photosensor. Therefore, in practice, the rotational speed of the heating roller 54 can be accurately determined by counting how many times it rotates in a predetermined period of time, for example, 10 seconds, or how many times the high/low signal changes in the case of split filler. can be detected.

Here, the predetermined time detected by the photosensor 63b provided in the rotation detecting member 63 of this configuration example takes into consideration the detection accuracy and the switching accuracy of the rotation speed of the drive motor that rotationally drives the fixing roller 52 or the pressure roller 55. can be determined as appropriate.

For example, in this configuration example, by setting the detection time to about 50 seconds for detection, a speed variation of 0.5% or less is detected, and the drive motor that rotationally drives the fixing roller 52 or the pressure roller 55 is detected. feedback to the rotation speed of

Further, the rotation detection member 63 is not limited to the one composed of the rotation filler 63f having four filler sheets as the member to be detected and the photosensor 63b as the detection member. For example, the number of fillers included in the rotating filler 63f is not limited to four.

The fixing device 100 shown in FIG. 3 is further provided with a refresh roller mechanism 40 for polishing and modifying the surface of the fixing belt 51 .

FIG. 4 is a diagram for explaining the function of the refresh roller mechanism of fixing device 100 shown in FIG. As shown in FIG. 4 , the refresh roller mechanism 40 includes a refresh roller 41 that grinds the surface of the fixing belt 51 , a refresh roller bracket 42 that supports the refresh roller 41 , and a drive motor 43 that rotates the refresh roller 41 . have. The refreshing roller 41 is in contact with the fixing roller 52 via the fixing belt 51 and is driven to rotate in the same direction as the fixing roller 51 by a drive motor (driving control mechanism). The refreshing roller 41 rotates at a linear speed ratio with respect to the fixing roller 52 . The drive control mechanism performs rotation control of the refreshing roller 41 according to instructions from the control unit 1000 . Specifically, the drive control mechanism controls the following refresh operation in response to the determination by the control unit 1000 that thermal expansion has occurred in the fixing roller 52 based on the detection result of the rotation speed of the fixing roller 52. Control is performed to change the rotation speed of the roller 41 .

FIG. 5 is a diagram showing an example of the linear speed ratio between the fixing roller and the refreshing roller. As shown in FIG. 5 , the refreshing roller 41 rotates at a predetermined linear velocity ratio with respect to the fixing roller 52 in order to improve the polishing performance of the fixing belt 51 , and rotates at a faster speed than the fixing belt 51 . In FIG. 5, for example, the refreshing roller 41 rotates at linear velocities of 900 mm/sec, 1350 mm/sec, and 1800 mm/sec, which are 3, 4.5, and 6 times.

FIG. 6 is a diagram showing the relationship between the linear velocity ratio between the fixing roller and the refreshing roller during thermal expansion and the refreshing performance. Here, the case where the thermal expansion of the fixing roller 52 is 1.5 mm (F1) and the case where it is 0.8 mm (F2) will be described as examples. When the thermal expansion of the fixing roller 52 is 1.5 mm, it is in a hot state, and when the thermal expansion of the fixing roller 52 is 0.8 mm, it is in a state immediately after being started from a cold state.

As shown in FIG. 6, when the thermal expansion is 1.5 mm and when the thermal expansion is 0.8 mm, the contact pressure of the refreshing roller 41 is stronger in the former case than in the latter case, so the former case has higher refreshing performance. Become. Also, it can be seen that the higher the linear velocity ratio, the higher the refresh performance. In FIG. 6, when the thermal expansion is 1.5 mm, the polishing performance exceeds the predetermined reference line (TH1) when the linear velocity ratio is 3.0, while the thermal expansion is 0. In the case of 0.8 mm, it can be seen that the polishing performance exceeds the predetermined reference value line (TH1) when the linear velocity ratio is 6.0.

FIG. 7 is a diagram showing the relationship between the linear velocity ratio between the fixing roller and the refresh roller during thermal expansion and the torque of the drive motor that drives the refresh roller. Here, as in the case of FIG. 6, the case where the thermal expansion of the fixing roller 52 is 1.5 mm (F3) and the case where it is 0.8 mm (F4) will be described as examples.

As shown in FIG. 7, when the thermal expansion is 1.5 mm and when the thermal expansion is 0.8 mm, since the contact pressure of the refreshing roller 41 is stronger in the former than in the latter, the driving torque is higher in the former. Become. Also, it can be seen that the higher the linear velocity ratio, the higher the driving torque. In FIG. 7, when the thermal expansion is 1.5 mm, the motor torque becomes less than the predetermined reference value line (TH2) when the linear velocity ratio is 3.0, while the thermal expansion is 0.5 mm. In the case of 8 mm, it can be seen that when the linear velocity ratio becomes 6.0, the motor torque falls below the line (TH2), which is the predetermined reference value.

From these two graphs shown in FIGS. 6 and 7, it can be seen that when the thermal expansion of the fixing roller 52 is 1.5 mm, both the refresh performance and the motor torque below a predetermined reference value are achieved at a linear speed ratio of 3 times. (circles in graphs F1 and F3), and when the thermal expansion of the fixing roller 52 is 0.8 mm, it is possible to achieve both refreshment performance and motor torque below a predetermined reference value at a linear speed ratio of 6 times. (circles in graphs F2 and F4). For example, the drive control mechanism controls the rotational speed of the refreshing roller 41 to decrease when the thermal expansion of the fixing roller 52 increases. When the fuser roller thermally expands, the speed of the fuser roller fuser belt increases, so by reducing the speed of the refresh roller when the speed of the fuser member increases, the torque of the refresh roller drive motor can be reduced, resulting in a permissible Torque will not be exceeded.

Thus, by changing the linear velocity ratio according to the thermal expansion of the fixing roller 52, that is, by changing the linear velocity of the refreshing roller 41 and the fixing roller 52 (or the fixing belt 51) according to the degree of thermal expansion, a predetermined It is possible to achieve both the drive motor torque equal to or less than the reference value of and the polishing performance of the refreshing roller 41 .

As described above, in the fixing device of this embodiment, the refreshing roller for polishing scratches on the surface of the endless fixing belt comes into contact with the fixing roller through the fixing belt. The outer diameter of the roller changes, and the contact pressure of the refreshing roller changes. For this reason, in the conventional fixing device, for example, after passing a large number of sheets, after passing an envelope, or after passing a small-size sheet, the thermal expansion of the fixing roller increases and the contact pressure of the refreshing roller increases. growing. As a result, there is a problem that the drive torque of the refreshing roller increases and exceeds the allowable torque of the motor. On the other hand, immediately after starting up the apparatus or after passing a small number of sheets, the thermal expansion of the fixing roller is reduced and the contact pressure of the refreshing roller is also reduced. As a result, there is a problem that the refresh performance is deteriorated, and it has been difficult to solve both the problems.

However, as in this embodiment, when the refresh roller 41 for modifying the surface of the fixing roller 52 and the drive control mechanism for rotating the refresh roller 41 are provided and the speed of the fixing roller 52 increases, By providing a configuration that reduces the rotational speed of the refresh roller 41, for example, when the thermal expansion of the fixing roller is small immediately after startup of the fixing device, or when the thermal expansion of the fixing roller is large after continuous paper feeding, etc. It is possible to achieve both suppression of an increase in the drive torque of the refreshing roller and refreshing performance regardless of the state of use. Although the speed of the fixing roller is detected, detection of the speed is synonymous with detection of the speed of the fixing belt.

In addition, in the fixing device in this embodiment, the following control may be performed. For example, the drive control mechanism determines that the target temperature of the fixing roller 52 according to preset paper type and paper thickness information is higher than a predetermined threshold value, and the number of sheets fed is greater than a predetermined set number. If so, the control of the refresh roller 41 described above is performed. As a result, when a large number of sheets are passed at a high set temperature, the temperature of the fixing roller rises and thermal expansion increases. , the torque of the drive motor for the refreshing roller can be reduced, and it is possible to prevent the allowable torque from being exceeded.

The target temperature of the fixing roller 52 according to the paper type and paper thickness information may be set by the user via the operation panel of the printer 200, which is an image forming apparatus in which the fixing device 100 is mounted. Thereby, the target temperature desired by the user can be set, and the rotation speed of the refreshing roller can be controlled according to the set value.

Although the present invention has been described above based on preferred embodiments, the present invention is not limited to those described in the above embodiments, and can be modified in various ways without departing from the scope of the invention.

100 fixing device 200 printer 1000 control section (detection means)
51 fixing belt (fixing member)
52 fixing roller 54 heating roller 55 pressure roller N fixing nip portion 62 rotation transmission means 63 rotation detection member 63b photo sensor 63f rotating filler 40 refresh mechanism 41 refresh roller (fixing surface modifying member)
42 refresh roller bracket 43 drive motor (drive control mechanism)

JP-A-2008-40365

Claims (7)

a fixing surface modifying member that modifies the surface of the rotationally driven fixing member;
detection means for detecting the speed of the fixing member;
a drive control mechanism for rotating the fixing surface modifying member,
The fixing surface modifying member rotates at a linear speed ratio with respect to the fixing member,
The drive control mechanism detects that the speed of the fixing member is detected by the detection means , and the polishing performance of the fixing surface modifying member exceeds a predetermined reference value, and the drive torque of the fixing surface modifying member reaches a predetermined value. Perform control to change the linear velocity ratio so that it is less than the reference value of
A fixing device characterized by: The fixing device according to claim 1,
The drive control mechanism adjusts the linear velocity ratio when the thermal expansion is small based on the determination that the fixing member is thermally expanding based on the detection result of the speed of the fixing member. When is large, perform control to make it larger,
A fixing device characterized by: The fixing device according to claim 1 or 2 ,
The drive control mechanism performs control to reduce the rotational speed of the fixing surface modifying member when the speed of the fixing member increases.
A fixing device characterized by: The fixing device according to any one of claims 1 to 3 ,
The drive control mechanism determines that the target temperature of the fixing member according to preset paper type and paper thickness information is higher than a predetermined threshold value, and more than a predetermined set number of sheets have been fed. performing the control when
A fixing device characterized by: The fixing device according to claim 4 ,
The target temperature of the fixing member according to the paper type and paper thickness information is set by a user via an operation panel of an image forming apparatus equipped with the fixing device.
A fixing device characterized by: The fixing member is an endless belt,
The fixing device according to any one of claims 1 to 5, characterized in that: An image forming apparatus comprising the fixing device according to any one of claims 1 to 6.

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