JP6766586B2 - Fixing device and image forming device - Google Patents

Description

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

Various image forming devices using an electrophotographic method have been devised as image forming devices for copiers, facsimiles, printers, etc., and are known techniques. In the image forming process, an electrostatic latent image is formed on the surface of the photosensitive drum, which is an image carrier, and the electrostatic latent image on the photosensitive drum is developed with toner, which is a developer, to make it visible and developed. The image is transferred to a recording medium (hereinafter, also referred to as paper) by a transfer device to support the image, and the unfixed toner image on the recording medium is fixed by a fixing device using pressure, heat, or the like. ..

Various types of fixing devices have been proposed. For example, the fixing roller is stretched between the fixing roller arranged to face the pressure roller (pressurizing member) and the fixing roller and the heating roller having a heat source. An endless fixing belt (fixing member) is provided, and the heat of the heating roller is applied to the recording medium via the fixing belt at the nip portion formed by pressure contact between the pressurizing roller and the fixing belt. A belt fixing method is known in which a contacted toner image is pressed against a recording medium and fixed.

Further, in the fixing device, a part of a sheet-shaped cleaning web (hereinafter, also referred to as a web) is pressure-welded to the fixing member or the pressure member by pressing the toner transferred to the fixing member or the pressure member without being completely fixed to the recording medium. It is known that a cleaning means (cleaning means) for cleaning by letting the material be provided is provided (for example, Patent Document 1). During the paper-passing operation to the fixing device, the web is periodically sent to a new surface to maintain its cleaning ability. Hereinafter, the fixing member and the pressurizing member to which the web is in pressure contact are referred to as a cleaning member.

In the belt fixing type fixing device, the fixing roller does not have a heat source, so if the fixing drive is continuously stopped when the fixing device is not passing paper such as during standby, the temperature of the fixing roller will drop due to natural heat dissipation. .. Then, even if the fixing belt is heated by the heating roller, the temperature is lowered by being absorbed by the fixing roller, the predetermined fixing temperature cannot be maintained, and a warm-up operation is required. In order to prevent the temperature from dropping more than necessary, it is known that the temperature maintenance rotation control that periodically heats and drives the fixing device is executed even in the standby state, and the printing operation is immediately maintained.

However, when the temperature maintenance rotation control is executed, the surface of the member to be cleaned may be rubbed by the pressure-welded web, and abrasion powder may be generated. When the standby state continues for a long time, wear debris accumulates on the nip (called a web nip) formed between the member to be cleaned and the web, and when a certain amount or more is accumulated, it slips through the web nip and stains the member to be cleaned. There is a risk that it will end up. If the paper is passed from this state after that, the abrasion powder is transferred to the recording medium, which may cause an abnormal image.

Regarding this point, as disclosed in Patent Document 2, it is conceivable to provide a separating mechanism for separating the web from the member to be cleaned, and to separate the web from the member to be cleaned when the paper is not passed.

However, if a separating mechanism for separating the web from the member to be cleaned is provided as in Patent Document 2, the configuration of the cleaning means becomes complicated and the cost increases.

Therefore, an object of the present invention is to provide a fixing device capable of maintaining good image quality with a simple configuration.

In order to achieve such an object, the fixing device according to the present invention includes a fixing roller, a heating roller heated by a heat source, at least a fixing belt stretched between the fixing roller and the heating roller, and the fixing belt. A pressure roller that press-contacts the fixing roller to form a nip portion, and a cleaning web that is arranged so as to always abut the fixing belt or the pressure roller as a member to be cleaned. A web drive unit that displaces the cleaning web to change the contact position of the cleaning web with the member to be cleaned, and a control unit that controls the drive of the fixing belt and the web drive unit are provided. In the standby state in which the fixing belt is not driven, the control unit performs temperature maintenance rotation control for driving the fixing belt at a predetermined timing, and at a predetermined timing according to the implementation status of the temperature maintenance rotation control. The standby cleaning control is performed by controlling the web driving unit to change the contact position of the cleaning web with the member to be cleaned.

According to the present invention, good image quality can be maintained with a simple configuration.

It is a schematic block diagram which shows one Embodiment of the image forming apparatus which concerns on this invention. It is a schematic block diagram which shows one Embodiment of the fixing device which concerns on this invention. It is a functional block diagram of a fixing device and an image forming device. It is a flowchart (1) of temperature maintenance rotation control. It is a flowchart (1) of the standby cleaning control. It is a flowchart (2) of the standby cleaning control. It is a flowchart (3) of the standby cleaning control. It is a flowchart (2) of temperature maintenance rotation control.

Hereinafter, the configuration according to the present invention will be described in detail based on the embodiments shown in FIGS. 1 to 8.

(Image forming device)
An embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an image forming apparatus 100.

In FIG. 1, the reading unit 12 is provided for scanning a document placed on a pressure plate, and is composed of a contact glass 20 on which the document is placed and an optical scanning system. The optical scanning system includes an exposure lamp 13, a first mirror 14, a second mirror 17, a third mirror 18, a lens 15, a CCD image sensor 16, and the like. The original image is read by the CCD image sensor 16 and converted into an electric signal for processing.

In the sheet document automatic scanning device A for automatically scanning the sheet document, the document placed on the platen B is fed to the position of the document scanning sensor G by the feeding roller C. The document passes through the document reading sensor G as it is at a constant speed, and at this time, the image on the front surface side of the document is read by the document reading sensor G. The read image data is sequentially stored in the image memory after performing image processing (various corrections, compression, etc.).

The writing unit 49 is composed of a laser output unit 19, an imaging lens 21, and a mirror 22, and the laser beam output from the writing unit 49 is applied to the photoconductor 30 of the image image forming system.

The procedure for printing the image imaged on the photoconductor 30 is roughly as follows. The paper loaded on the first tray 23, the second tray 24, and the third tray 25 is fed by the first paper feed device 26, the second paper feed device 27, and the third paper feed device 28, respectively, and is a vertical transfer unit. The 29 conveys the photoconductor 30 to a position in front of the photoconductor 30.

The image data on the image memory is written on the photoconductor 30 by the laser beam from the writing unit 49, and a toner image is formed by passing through the developing unit 35. The toner image on the photoconductor 30 is transferred while the paper is conveyed by the transport belt 31 at a constant speed with the rotation of the photoconductor 30 as the toner image moves. After that, the image is fixed by the fixing device 1 and discharged to the paper ejection tray 33 by the paper ejection unit 32.

When an image is imaged on both sides, the paper fed from the trays 23 to 25 and the image is imaged is reversed and the claws are switched. As a result, the paper is not guided to the output tray 33 side, but is conveyed to the double-sided inlet transfer path 38, guided to the reversing unit 37 provided in the double-sided transfer unit 36, and temporarily stored in the switchback transfer path 41. It is fed in the reverse direction (refeeding direction) by the return transport means, guided downward by the reverse paper ejection switching claw, inverted, and fed to the double-sided intermediate transport path 43 provided below the reverse paper ejection switching claw. Then, it is sent to the vertical transport unit 29 again by the intermediate transport means 40 and the double-sided outlet transport means 42 connected to the drive source (motor), the image is printed on the back surface, and then the paper is discharged.

Further, when the paper is inverted and ejected, the paper inverted by the switchback unit 37 is sent out to the inverted paper ejection transport path 39 without passing through the double-sided intermediate transport path 43 by the paper ejection reverse switching claw, and is ejected again. It is returned to the paper unit 32 and discharged to the outside of the main body.

The paper ejected from the main body is ejected to either the output tray 33 or the finisher 44 of the main body by the output destination switching claw. The paper discharged to the finisher 44 passes through the punch unit 48 for punching holes, and is once stacked on the stack tray 45 for stapling.

After all the paper is stored in the stack tray, the bundle of paper is stapled by the stapler unit 46 and discharged to the discharge tray 47.

(Fixing device)
An embodiment of the fixing device according to the present invention will be described with reference to FIG. FIG. 2 is a schematic configuration diagram showing the fixing device 1.

The fixing device 1 is between the control unit 10, the heating roller 51, the fixing roller 52, the fixing belt 53 stretched on the heating roller 51 and the fixing roller 52, and the fixing belt 53 by pressing the fixing roller 52. A pressure roller 55 for forming a nip portion, a cleaning means including a cleaning web 58 and the like, a temperature sensor 60 (temperature detecting means) and the like are provided. Further, the heating roller 51 has a heater 50 for a heating roller as a heat source, and the pressurizing roller 55 has a heater 54 for a pressurizing roller as a heat source. The rotational operation of the heating roller 51 and the fixing roller 52 heats the entire surface of the fixing belt 53 from the heating roller 51 in the circumferential direction.

In the fixing device 1, the recording medium P carrying the toner image T is passed through the nip portion of the fixing belt 53 and the pressure roller 55 formed by pressure contact between the fixing roller 52 and the pressure roller 55 to perform heat fixing. It is what you do. The heating roller 51, the fixing roller 52, and the pressurizing roller 55 are pivotally supported in the longitudinal direction of the housing of the fixing device 1, and the driving means and the like of each roller are fixedly held in the housing.

The tip of the recording medium P through which the nip portion has passed is separated by a separation means (separation plate, separation claw, etc.) arranged on the fixing roller 52 side or the pressure roller 55 side, and is discharged to the next step.

The heating roller 51 is, for example, a thin-walled cylinder made of a metal material, and a heater 50 for a heating roller is fixedly installed inside the cylinder. As the heater 50 for the heating roller, for example, a halogen heater, a carbon heater, or the like can be used. Further, both ends of the heating roller heater 50 are fixed to the housing of the fixing device 1.

The fixing roller 52 does not have a heat source, and is formed by covering a highly rigid core material (core metal) such as metal (iron or aluminum) with a thick elastic layer such as silicone rubber.

The fixing belt 53 is hung around the fixing roller 52 and the heating roller 51, and is in close contact with the heating roller 51 and the fixing roller 52. The nip portion is formed by pressing the pressurizing roller 55 against the fixing belt 53 configured in this way against the portion corresponding to the fixing roller 52.

The fixing belt 53 is, for example, an endless belt having a multi-layer structure in which an elastic layer such as silicone rubber and a release layer are sequentially laminated on a base layer made of PI (polyimide) resin and having a layer thickness of, for example, 90 μm.

The elastic layer of the fixing belt 53 has, for example, a layer thickness of about 200 μm and is made of an elastic material such as silicone rubber, fluororubber, or foamable silicone rubber. The release layer of the fixing belt 53 has, for example, a layer thickness of about 20 μm and is made of PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin), polyimide, polyetherimide, PES (polyethersulfide) or the like. It is formed. Further, by providing the release layer on the surface layer of the fixing belt 53, the release property (peeling property) with respect to the toner (toner image) is ensured.

Further, the fixing belt 53 is composed of, for example, a PI belt which is an endless film of a heat-resistant resin having a thickness of 90 μm, and an offset inhibitor such as PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin) is formed on the surface layer. Is coated.

The pressure roller 55 is, for example, a roller member in which an elastic layer such as fluororubber, silicone rubber, or foamable silicone rubber is formed on a core metal such as SUS304. Further, a pressurizing roller heater 54 as a heat source is fixedly installed inside the cylindrical body.

The fixing roller 52 and the pressure roller 55 are rubber rollers arranged to face each other, and the pressure roller 55 is pressed toward the center of the fixing roller 52 via the fixing belt 53, so that the pressure roller 55 is pressed. A nip portion is formed between the fixing belt 53 and the fixing belt 53. Further, the size of the nip width can be controlled by controlling the pressing force (pressing force) of the pressurizing roller 55 toward the fixing roller 52 side. It is also preferable that the pressurizing roller 55 can be separated from the fixing roller 52 in the standby state of the fixing device 1.

The pressure roller 55 is provided with cleaning means. The cleaning means includes a cleaning web 58, a pressing roller 57, a supply unit 59, and a take-up roller 56. A cleaning web 58 made of chemically synthesized fibers, cellulose, or the like is pressed against the pressure roller 55 by a sponge-like elastic pressure roller 57, and a small amount of the toner image T adheres to the fixing belt 53 when the toner image T is fixed. The offset toner is moved to the pressure roller 55 and scraped by the cleaning web 58.

In the supply section 59 of the cleaning web 58, an unused cleaning web 58 is wound around the shaft core, passes between the pressing roller 57 and the pressing roller 55, and is connected to the winding roller 56. The take-up roller 56 is rotated by being driven by a web drive motor 61 which is a driving means thereof. The cleaning web 58 can be updated from the supply unit 59 to a new surface by the take-up roller 56 performing a take-up operation by driving the web drive motor 61 at a predetermined timing.

In the present embodiment, the cleaning means is provided on the pressure roller 55 side and the cleaning web 58 is pressed against the pressure roller 55. However, the cleaning means is provided on the fixing belt 53 side and the cleaning web 58 is pressed against the fixing belt 53. It may be configured to be used. Further, the configuration of the cleaning means is not limited to the example of FIG. 2 as long as the cleaning web 58 is brought into contact with the member to be cleaned to change the contact position.

The output of the heating roller heater 50 is controlled by the power supply unit (AC power supply) of the image forming apparatus 100, and the heating roller 51 is heated by the radiant heat from the heating roller heater 50. Further, heat is applied to the unfixed toner image T on the recording medium P from the surface of the fixing belt 53 heated by the heating roller 51. Similarly, the output of the pressurizing roller heater 54 is controlled by the power supply unit (AC power supply) of the image forming apparatus 100, and the pressurizing roller 55 is heated by the radiant heat from the pressurizing roller heater 54.

The output control of the heater 50 for the heating roller and the heater 54 for the pressurizing roller is the detection result of the surface temperature by the temperature sensor 60 such as a thermopile provided at a position facing the surface at an arbitrary position of the fixing belt 53 in contact or non-contact. It is made based on. In the present embodiment, the temperature sensor 60 is provided on the fixing belt 53 in a non-contact position at a position facing the fixing roller 52. The installation of the temperature sensor in the fixing device 1 is not limited to this, and the temperature sensor may be provided at another position. For example, a temperature sensor is provided in contact or non-contact at a position facing the surface of the pressure roller 55 at an arbitrary position, and the output control of the pressure roller heater 54 is controlled by the temperature sensor for the pressure roller. It may be made based on the detection result of.

FIG. 3 is a functional block diagram of the image forming apparatus 100 and the fixing apparatus 1. The control unit 10 may be the control unit of the fixing device 1, or the control unit of the image forming device 100 may also serve as the control unit 10.

In the control unit 10, for example, a CPU 70 as a calculation unit, a RAM 71 or ROM 72 as a storage unit, an input / output interface 73, and the like are connected via a bus.

The control unit 10 controls the fixing drive motor 62 to control the driving of the fixing belt 53. The fixing drive motor 62 is, for example, a motor that rotationally drives the fixing roller 52, but is not limited thereto. Further, the web drive motor 61 is controlled to control the drive of the cleaning means (cleaning web 58). Further, each part of the image forming apparatus 100 and the fixing apparatus 1 is controlled, such as control of the heaters 50 and 54 based on the detection result of the temperature sensor 60, input reception from the operation panel 63, display control, and the like.

It should be noted that how to store the necessary information in each storage unit is not particularly limited, but for example, the RAM 71 contains the usage rate of the cleaning web 58 and the temperature maintenance rotation cumulative value counter described later. , Standby cleaning operation cumulative counter, etc. are temporarily stored. Further, the ROM 72 contains a drive time table of the web drive motor 61 with respect to the usage rate of the cleaning web 58, PID control parameters, a target temperature, a threshold value for determining whether or not temperature maintenance rotation control can be performed, which will be described later, and a standby cleaning operation. Threshold Sa, standby cleaning operation cumulative counter thresholds Sb, Sc, temperature maintenance rotation time set value, change amount Rr, and minimum rotation time Tr, energy saving mode transition time set value, change amount Re, and minimum transition time Te , Etc. are memorized.

[Temperature maintenance rotation control (1)]
An example of temperature maintenance rotation control executed by the fixing device 1 will be described. FIG. 4 is a flowchart showing a first embodiment of temperature maintenance rotation control.

When the fixing device 1 is in a standby state (S101) such as when the paper is not passed, the temperature sensor 60 continuously detects the surface temperature of the fixing belt 53 on the fixing roller 52 (S102).

When it is detected that the detected temperature is equal to or lower than a predetermined threshold value (for example, 100 ° C.) (S103: Y), the temperature maintenance rotation control for a predetermined time (for example, 30 sec) is executed (S104). After executing the temperature maintenance rotation control, the process returns to S102.

The temperature maintenance rotation control drives the heating roller 51, the fixing roller 52, the pressure roller 55, and the fixing belt 53 with the heating roller heater 50 lit. The lighting of the heater 50 for the heating roller is controlled so that the fixing belt 53 maintains a predetermined temperature (for example, 160 ° C.) by PID (Proportional-Integral-Differential Controller) control by the temperature sensor 60 and other temperature sensor values. To.

By this temperature maintenance rotation control, the fixing roller 52 is heated via the fixing belt 53 and kept at an appropriate temperature or higher.

However, by implementing the temperature maintenance rotation control as shown in FIG. 4, the surface of the member to be cleaned may be rubbed by the web 58 that is in pressure contact during driving, and abrasion powder may be generated. Accumulation of abrasion powder on the web nip may contaminate the member to be cleaned.

Therefore, the fixing device (fixing device 1) according to the present embodiment includes a fixing roller (fixing roller 52), a heating roller (heating roller 51) heated by a heat source (heating roller heater 50), and at least a fixing roller. A fixing belt (fixing belt 53) stretched over the heating roller, a pressure roller (pressurizing roller 55) that presses against the fixing roller via the fixing belt to form a nip, and a fixing belt or pressure roller. The cleaning web (cleaning web 58), which is arranged so as to be in constant contact with the member to be cleaned, and the cleaning web are displaced to change the contact position of the cleaning web with the member to be cleaned. A web drive unit (winding roller 56, web drive motor 61) to be driven, and a control unit (control unit 10) for controlling the drive of the fixing belt and the web drive unit are provided, and the control unit is not driven by the fixing belt. In a certain standby state, temperature maintenance rotation control for driving the fixing belt at a predetermined timing is performed, and the web drive unit is controlled at a predetermined timing according to the implementation status of the temperature maintenance rotation control to cover the cleaning web. The standby cleaning control is performed to change the contact position with the cleaning member. In addition, the code in parentheses and the application example are shown.

[Standby cleaning control (1)]
FIG. 5 is a flowchart showing a first embodiment of standby cleaning control. As described above, the temperature maintenance rotation control is started when a predetermined condition is satisfied in the standby state (S201). Next, it is determined whether or not the temperature maintenance rotation cumulative value is equal to or higher than the standby cleaning operation threshold value Sa (S202).

Here, the "temperature maintenance rotation cumulative value" is, for example, the cumulative value of the drive time of the temperature maintenance rotation control (for example, the drive time of the web drive motor 61). Further, the cumulative value of the drive amount of the temperature maintenance rotation control (for example, the drive amount of the web drive motor 61) may be used. Further, the “standby cleaning operation threshold value Sa” is a preset threshold value, and it is also preferable that the threshold value can be arbitrarily changed from an input device such as an operation panel 63 of the image forming apparatus 100.

When the cumulative temperature maintenance rotation value is equal to or higher than the standby cleaning operation threshold value Sa (S202: Y), the web drive motor 61 is operated for a predetermined time (Ta seconds) to wind the cleaning web 58 (s). S203). This is called a standby cleaning operation.

Next, the value for one operation this time is added to the cumulative value of temperature maintenance rotation (S204). For example, when the cumulative value of temperature maintenance rotation is the cumulative value of driving time, 30 sec is added to this counter.

On the other hand, when the cumulative temperature maintenance rotation value is less than the standby cleaning operation threshold value Sa (S202: N), the standby cleaning operation is not executed and the addition process of the cumulative temperature maintenance rotation value is executed (S204).

According to the first embodiment of the standby cleaning control, the drive time and the drive amount of the temperature maintenance rotation control are cumulatively counted, and when the result becomes a certain value or more, the standby cleaning operation for winding the web is performed. By carrying out the above, it is possible to prevent an abnormal image caused by rubbing between the web and the member to be cleaned, and maintain the image quality. At this time, since it is not necessary to provide a separation mechanism between the web and the member to be cleaned, the image quality can be maintained easily and at low cost.

[Standby cleaning control (2)]
Hereinafter, other preferred embodiments of the standby cleaning control carried out by the fixing device 1 according to the present invention will be described. The description of the same points as in the above embodiment will be omitted as appropriate.

In the second embodiment, the winding operation of the cleaning web 58 during the printing operation (referred to as the cleaning operation during the printing operation) and the operation time of the above-described standby cleaning operation will be described.

During the printing operation, if printing is repeated, a small amount of offset toner is collected by the cleaning web 58, and if the amount exceeds the permissible value, the toner may slip through the cleaning web 58 and the recording medium P may become dirty. Therefore, during the printing operation, the cleaning web 58 is wound up every time a predetermined time elapses, and the cleaning operation during the printing operation is performed to refresh the contact surface with the pressure roller 55.

At this time, the roller diameter of the take-up roller 56 changes between the time when the remaining amount of the supply unit 59 of the cleaning web 58 is large (initial state) and the time when the remaining amount is low (aging state). That is, the roller diameter of the take-up roller 56 is larger in the time-lapse state because more cleaning webs 58 are taken up. Therefore, when the rotation speed of the web drive motor 61 is constant, the winding amount of the cleaning web 58 is larger in the time-lapse state.

Therefore, in the cleaning operation during the printing operation, the drive time of the web drive motor 61 is gradually set from the initial state to the aging state so that the winding amount of the cleaning web 58 becomes a desired winding amount (winding amount W1). It is controlled to be shorter.

On the other hand, in the standby cleaning operation, since the object to be collected is abrasion powder and fine particles, slip-through from the cleaning web 58 occurs more than the offset toner which melts during printing and the toner adheres to each other. Cheap. Therefore, it is preferable to carry out the winding operation so that the desired winding amount (winding amount W2) in the standby cleaning operation satisfies W2> W1.

Further, as an appropriate upper limit setting of the winding amount W2 during the standby cleaning operation, when the nip width of the nip (web nip) formed by the pressing roller 57 and the pressing roller 55 is W3, one time is set. It is preferable to add the winding amount of W2 ≦ W3 + W1 as a margin.

As a result, the contact surface between the cleaning web 58 and the pressure roller 55 can be completely refreshed. Further, since the web surface of the cleaning web 58 that comes into contact with the pressurizing roller 55 is all a new surface, the effect of preventing abnormal images is small even if W3 + W1 or more is wound. Therefore, by setting this as the upper limit, wasteful consumption of the cleaning web 58 can be avoided.

According to the second embodiment of the standby cleaning control, fine abrasion powder is set by setting the drive time or drive amount of the standby cleaning operation to be larger than the drive time or drive amount of the cleaning operation during printing operation. It is possible to surely refresh the web surface to which the shavings are attached and prevent abnormal images due to abrasion powder.

[Standby cleaning control (3)]
FIG. 6 is a flowchart showing a third embodiment of standby cleaning control. When the above-mentioned standby cleaning operation is performed (S301, S203 in FIG. 5), one operation information is added to the standby cleaning operation cumulative counter (S302). The operation information for one time here is, for example, the number of times the standby cleaning operation is performed, the drive time, the drive amount, and the like. Here, the number of implementations will be described as an example.

Next, it is determined whether or not the value of the standby cleaning operation cumulative counter is equal to or greater than a predetermined value (threshold value Sb) (S303). When the operation information is the number of executions, it is determined whether or not the operation information has been executed more than a predetermined number of times.

When the value of the standby cleaning operation cumulative counter is equal to or greater than the threshold value Sb (S303: Y), the set value of the temperature maintenance rotation control execution time (referred to as temperature maintenance rotation time) is set to "current set value-Rr seconds". , Adjust to be shorter than the currently set time (S304). If Rr is set to, for example, 5 seconds and the current temperature maintenance rotation time is 30 seconds, the adjusted temperature maintenance rotation time is 25 seconds. In the present embodiment, the temperature maintenance rotation time is reduced by subtracting the current set value by Rr seconds, but even if the temperature maintenance rotation time is reduced by a predetermined ratio as "current set value x coefficient". Good.

By shortening the temperature maintenance rotation time in this way, the rubbing time between the cleaning web 58 and the pressure roller 55 is reduced, so that the wear of the pressure roller 55 can be reduced.

After adjusting the temperature maintenance rotation time, it is determined whether or not the adjusted temperature maintenance rotation time is less than the minimum rotation time Tr of the temperature maintenance rotation control (S305). Here, Tr is the minimum rotation time required for the fixing roller 52 to be maintained at an appropriate temperature by the temperature maintenance rotation control.

When the temperature maintenance rotation time after adjustment is less than the minimum rotation time Tr (S305: Y), the temperature maintenance rotation time is readjusted to Tr (S306). When the temperature maintenance rotation time after adjustment exceeds the minimum rotation time Tr (S305: N), and after readjustment to Tr (S306), the value of the standby cleaning operation cumulative counter is reset (S307). ..

On the other hand, when the value of the standby cleaning operation cumulative counter is less than the threshold value Sb (S303: N), the process ends as it is. It is also preferable that each set value such as Rr and Sb can be arbitrarily changed from an input device such as the operation panel 63 of the image forming apparatus 100.

In the third embodiment, when it is detected that the standby cleaning operation is continuously executed, that is, the operating condition is to be kept in the standby state for a long time, the temperature maintenance rotation time is shortened. ing. Therefore, if the web winding operation during the printing operation is executed before the condition of the value of the standby cleaning operation cumulative counter ≥ the threshold value Sb is satisfied, the value of the standby cleaning operation cumulative counter is reset.

According to the third embodiment of the standby cleaning control, the drive time or the drive amount of the temperature maintenance rotation control is adjusted to be less than the current value when a condition in which the standby cleaning operation is continuously performed is detected. As a result, the rubbing time between the web and the member to be cleaned can be reduced, the wear of the member to be cleaned can be reduced, and the occurrence of an abnormal image can be suppressed. In addition, since the frequency of standby cleaning operations can be suppressed, the life of the web can be extended, and maintenance costs and resources can be saved by replacing the web.

[Standby cleaning control (4)]
FIG. 7 is a flowchart showing a fourth embodiment of standby cleaning control. When the above-mentioned standby cleaning operation is performed (S401, S203 in FIG. 5), one operation information is added to the standby cleaning operation cumulative counter (S402). The operation information for one time here is, for example, the number of times the standby cleaning operation is performed, the drive time, the drive amount, and the like. Here, the number of implementations will be described as an example.

Next, it is determined whether or not the value of the standby cleaning operation cumulative counter is equal to or higher than a predetermined value (threshold value Sc) (S403). If the operation information is the number of executions, it is determined whether or not the operation information has been executed more than a predetermined number of times.

When the value of the standby cleaning operation cumulative counter is equal to or greater than the threshold value Sc (S403: Y), the set value of the energy saving mode transition time is set to "current set value-Re minutes", which is shorter than the currently set time. Adjust (S404). The energy-saving mode is a state in which control such as suppressing the power consumption of the fixing device is performed in order to reduce the power consumption of the device, and the temperature maintenance rotation control is not performed in the energy-saving mode. Further, Re is set to, for example, 15 minutes, and when the current energy saving mode transition time is 60 minutes, the adjusted energy saving mode transition time is 45 minutes. In the present embodiment, the energy saving mode transition time is reduced by reducing the current setting value by Re, but the energy saving mode transition time may be reduced by a predetermined ratio as "current setting value x coefficient". ..

By shortening the transition time to the energy saving mode in this way, the rubbing time between the cleaning web 58 and the pressure roller 55 is reduced, so that the wear of the pressure roller 55 can be reduced.

After adjusting the energy-saving mode transition time, it is determined whether the adjusted energy-saving mode transition time is less than the minimum transition time Te (S405). Here, Te is preferably a time that can surely prevent the occurrence of an abnormal image due to abrasion powder, and is preferably the longest time that can be set in order to improve the convenience of the user. For example, if the transition time to the energy saving mode is set to 1 minute, an abnormal image does not occur, but the energy saving mode is frequently entered, and a warm-up operation is performed each time before printing, which reduces convenience. Therefore, when the longest time during which an abnormal image does not occur, for example, that time is 30 minutes, 30 minutes is set as the minimum transition time Te.

If the adjusted energy-saving mode transition time is less than the minimum transition time Te (S405: Y), the energy-saving mode transition time is readjusted to Te (S406). When the energy saving mode transition time after adjustment exceeds the minimum transition time Te (S405: N), and after readjustment to Te (S406), the value of the standby cleaning operation cumulative counter is reset (S407). ..

On the other hand, when the value of the standby cleaning operation cumulative counter is less than the threshold value Sc (S403: N), the process ends as it is. It is also preferable that each set value such as Re and the threshold value Sc can be arbitrarily changed from an input device such as the operation panel 63 of the image forming apparatus 100.

In the fourth embodiment, when it is detected that the standby cleaning operation is continuously executed, that is, it is a usage condition that the standby state is placed for a long time, the standby state is not set for a long time. The transition time to the energy saving mode is shortened. Therefore, if the web winding operation during the printing operation is executed before the condition of the value of the standby cleaning operation cumulative counter ≥ the threshold value Sc is satisfied, the value of the standby cleaning operation cumulative counter is reset.

Since the energy saving mode transition time is an item that can be freely set by the user, it is assumed that some users do not want to change the energy saving mode transition time. Therefore, it is preferable that the user can set the necessity of the adjustment control of the energy saving mode transition time from the operation panel 63. Further, when the adjustment condition of the energy saving mode transition time is satisfied and the set value is changed, the possibility of the change may be displayed on the operation panel 63 as a confirmation message so that the user can select whether or not the setting value can be changed. Further, in the present embodiment, the control described in the third embodiment may also be executed.

According to the fourth embodiment of the standby cleaning control, when the condition that the standby cleaning operation is continuously performed is detected, the temperature maintenance rotation is performed by adjusting the energy saving mode transition time to be shorter than the current value. Since the frequency of control is reduced, it is possible to reduce the wear of the member to be cleaned and suppress the occurrence of abnormal images. In addition, since the frequency of standby cleaning operations can be suppressed, the life of the web can be extended, and maintenance costs and resources can be saved by replacing the web.

[Temperature maintenance rotation control (2)]
In the temperature maintenance rotation control of FIG. 4, the temperature sensor 60 continuously detects the surface temperature of the fixing belt 53 on the fixing roller 52, and when the detected temperature becomes equal to or less than a predetermined threshold value, the temperature maintenance rotation control is performed. Explained to execute.

Another example of temperature maintenance rotation control will be described. FIG. 8 is a flowchart showing a second embodiment of temperature maintenance rotation control.

When the fixing device 1 is in a standby state (S501) such as when the paper is not passed, the time during which the fixing device 1 is not driven is counted (S502).

When the non-driving time of the fixing device 1 exceeds a predetermined time (for example, 300 sec) (S503: Y), the temperature maintenance rotation control for the predetermined time (for example, 30 sec) is executed (S504). After executing the temperature maintenance rotation control, the process returns to S502. The temperature maintenance rotation control and the lighting control of the heater at the time of control are the same as in the case of FIG. Further, it is also preferable that the threshold value (300 sec) of the non-driving time for determining the start of the temperature maintenance rotation control and the temperature maintenance rotation time (30 sec) can be changed from the operation panel 63 or the like. The temperature maintenance rotation control, which is a prerequisite for the standby cleaning control of the first to fourth embodiments described above, may be any of the methods of FIGS. 4 and 8.

According to this temperature maintenance rotation control, the temperature of the fixing roller 52 is kept above a desired temperature by counting the time when the fixing device 1 is not driven and performing the temperature maintenance rotation control based on the accumulated time. be able to.

Although the above-described embodiment is a preferred example of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.

1 Fixing device 10 Control unit 12 Reading unit 13 Exposure lamp 14 First mirror 15 Lens 16 CCD image sensor 17 Second mirror 18 Third mirror 19 Laser output unit 20 Contact glass 21 Imaging lens 22 Mirror 23 First tray 24 Second Tray 25 3rd tray 26 1st paper feed device 27 2nd paper feed device 28 3rd paper feed device 29 Vertical transport unit 30 Photoreceptor 31 Transport belt 32 Paper discharge unit 33 Paper discharge tray 35 Development unit 36 Double-sided transport unit 37 Inverted Unit 38 Double-sided inlet transport path 39 Reverse paper discharge transport path 40 Intermediate transport means 41 Switchback transport path 42 Double-sided outlet transport means 43 Double-sided intermediate transport path 44 Finisher 45 Stack tray 46 Stapler unit 47 Discharge tray 48 Punch unit 49 Writing unit 50 Heating Roller heater 51 Heating roller 52 Fixing roller 53 Fixing belt 54 Pressurizing roller heater 55 Pressurizing roller 56 Winding roller 57 Pressing roller 58 Cleaning web 59 Supply unit 60 Temperature sensor 61 Web drive motor 62 Fixing drive motor 63 Operation panel 70 CPU
71 RAM
72 ROM
73 Input / output interface 100 Image forming device A Sheet document automatic reading device B Document stand C Feeding roller G Document reading sensor P Recording medium T Toner image

Japanese Unexamined Patent Publication No. 2012-5836 Japanese Patent No. 3936501

Claims (6)

With the fixing roller
A heating roller that is heated by a heat source,
At least a fixing belt stretched between the fixing roller and the heating roller,
A pressure roller that presses against the fixing roller via the fixing belt to form a nip portion,
With the fixing belt or the pressure roller as a member to be cleaned, a cleaning web arranged so as to be in constant contact with the member to be cleaned, and a cleaning web.
A web drive unit that displaces the cleaning web to change the contact position of the cleaning web with the member to be cleaned.
A control unit for driving the fixing belt and controlling the web drive unit is provided.
The control unit
In the standby state where the fixing belt is not driven,
While performing temperature maintenance rotation control to drive the fixing belt at a predetermined timing,
Depending on the implementation of the temperature maintaining rotational control, pre SL have lines during standby cleaning control for changing the contact position of the controls the web drive unit to the object cleaning member of the cleaning web, in the standby state A fixing device characterized in that the drive time or drive amount of the web drive unit in the standby cleaning control is made larger than the drive time or drive amount of the web drive unit in the cleaning control during paper passing . The control unit
If the Oite, it is used the conditions placed on standby for a predetermined long time has been detected when the wait time cleaning control sheet passing is not performed is performed sequentially, rotating said temperature maintained The fixing device according to claim 1 , wherein the driving time or the driving amount of the control is reduced. The control unit
If the Oite, it is used the conditions placed on standby for a predetermined long time has been detected when the wait time cleaning control without the sheet passing is made is continuously performed, the power saving mode conversion time The fixing device according to claim 1 or 2 , wherein the fixing device is made shorter. The fixing roller is provided with a temperature detecting means provided in contact or non-contact at a position where the fixing belt is stretched.
The control unit
The fixing device according to any one of claims 1 to 3 , wherein the feasibility of executing the temperature maintenance rotation control is determined according to the detection result of the temperature detecting means. The control unit
The invention according to any one of claims 1 to 3 , wherein the non-driving time of the fixing device in the standby state is measured, and whether or not the temperature maintenance rotation control can be executed is determined according to the non-driving time. Fixing device. An image forming apparatus comprising the fixing apparatus according to any one of claims 1 to 5 .

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