JP2012037736A - Image-forming device, and control method and control program for clutch in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-forming device and others capable of reducing power consumption through effective power supply to a clutch that drives and controls driven objects whose load changes with time.SOLUTION: An image-forming device comprises: a clutch 4 for driving and controlling driven objects 120a, 120b, 120c and 120d whose load changes with time with receiving power supply from electric power source; and control means 1 for controlling the clutch with a duty ratio of pulse-width modulation signal as well as for setting the duty ratio of pulse-width modulation signal to a first value at the time of start-up rotation before connection between the clutch and the driven objects finishes and changing the duty ratio of pulse-width modulation signal to a second value less than the first value in accordance with a loading state of the driven objects at the time of steady rotation after the connection finishes.

Description

  The present invention relates to an image forming apparatus used for an MFP (Multi Function Peripherals), which is a multifunction digital image forming apparatus, and a clutch control method and control program in the apparatus.

  In an image forming apparatus, an electromagnetic clutch is applied to a driving object used for a replaceable component unit, for example, a toner cartridge filled with toner, a toner stirring roller or a fixing roller which is a driving object used for a fixing unit. In some cases, the roller is engaged and the clutch is electrically controlled to control the rotational driving state of the roller including connection and release of the clutch. In this case, electrical control of the clutch is performed based on a duty ratio of a pulse width modulation (PWM) signal applied to the clutch.

  By the way, when mounting this type of clutch, a clutch having a capacity corresponding to the maximum load torque of the toner stirring roller, the fixing roller, or the like, which is an object to be driven, is selected.

  Conventionally, in the case where the clutch is connected to one of the pair of conveying rollers activated by the stepping motor, the clutch is pulse-width-modulated at the time of activation so that the stepping motor does not step out due to a sudden torque fluctuation caused by coupling of the clutch. A technique has been proposed in which the torque is gradually changed by control (see, for example, Patent Document 1).

JP 2004-238157 A

  In recent years, with the demand for energy saving, image forming apparatuses are also required to reduce power consumption as much as possible.

  However, with this type of clutch, even if the load of the driven object changes according to the state of the component unit, the maximum power is supplied according to the maximum load regardless of the load change. There was a problem that power consumption was relatively large. For example, in the toner agitation roller, even when the toner is agitated and the load becomes light, the maximum power is applied, and thus there is a problem that power is wasted.

  Actually, there is almost no situation in which a driving object such as a roller used in a consumable unit has a maximum load, and extra power is used.

  For such a problem, the technique described in Patent Document 1 cannot provide a solution.

  The present invention has been made in view of the above circumstances, and is intended to reduce power consumption by effectively supplying power to a clutch that drives and controls a driving object whose load changes over time. It is an object of the present invention to provide an image forming apparatus capable of performing the above and a clutch control method in the apparatus, and further to provide a clutch control program for causing a computer of the image forming apparatus to execute the control method.

The above problem is solved by the following means.
(1) A driving object whose load changes with time is controlled by receiving a power supply from a power source, and the clutch is controlled by a duty ratio of a pulse width modulation signal. During start-up rotation until completion of connection with an object, the duty ratio of the pulse width modulation signal is set to a first value, and during steady rotation after completion of connection, the duty ratio of the pulse width modulation signal is set to the driving object. An image forming apparatus comprising: a control unit that changes the second value smaller than the first value in accordance with a load state of the image forming apparatus.
(2) When the component unit including the driving object is replaced, the control means sets the duty ratio of the pulse width modulation signal after a predetermined rotation or a predetermined time from the start of steady rotation of the driving object. The image forming apparatus according to claim 1, wherein the second value is changed to a smaller value.
(3) When the driving object is not operated for a predetermined time, the control means sets the duty ratio of the pulse width modulation signal to a second value after a predetermined rotation or a predetermined time from the start of steady rotation of the driving object. The image forming apparatus according to claim 1, wherein the value is changed from a value of 1 to a smaller value.
(4) The control unit changes the duty ratio of the pulse width modulation signal to the second value at the start of steady rotation when the component unit including the driving object is replaced, and the driving object The image forming apparatus according to claim 1, wherein the duty ratio of the pulse width modulation signal at the time of steady rotation is increased in accordance with the amount of rotation.
(5) The control means changes the duty ratio of the pulse width modulation signal signal to the second value at the start of steady rotation, and then sets a plurality of duty ratios of the pulse width modulation signal according to the load state of the driven object. The image forming apparatus according to claim 1, wherein the image forming apparatus is changed once.
(6) The image forming apparatus according to (2) or (3), wherein the component unit is a toner cartridge filled with toner, and the driven object is a toner stirring roller.
(7) The image forming apparatus according to (4), wherein the component unit is a fixing unit, and the driven object is a fixing roller.
(8) A method for controlling the clutch in an image forming apparatus including a clutch that controls driving of a driving object whose load changes with time by receiving power supply from a power source, the pulse being a pulse width modulation signal The duty ratio of the pulse width modulation signal is set to a first value during start-up rotation until the clutch is fully engaged, and the pulse width modulation signal is determined during steady rotation after completion of the connection. And a control step of changing the duty ratio to a second value smaller than the first value in accordance with a load state of the driven object.
(9) A clutch control program for causing a computer of an image forming apparatus provided with a clutch to drive an object whose load changes over time by receiving power supply from a power source. Controls the clutch according to the duty ratio of the pulse width modulation signal, and sets the duty ratio of the pulse width modulation signal to the first value during start-up rotation until the clutch is fully engaged, During steady rotation, a duty ratio of the pulse width modulation signal is changed to a second value smaller than the first value according to the load state of the driven object. Control program.

  According to the invention described in item (1) above, the clutch is controlled by the duty ratio of the pulse width modulation signal. In addition, the duty ratio of the pulse width modulation signal is set to a first value during start-up rotation until the clutch completes connection with the drive object, and during the steady rotation after connection completion, the pulse width modulation signal The duty ratio is changed to a second value smaller than the first value according to the load state of the driven object. For this reason, power consumption can be reduced compared to the conventional case where the maximum power is always supplied according to the maximum load regardless of the load change of the driven object, and the optimum according to the load of the driven object. The power control of the clutch can be performed, and the power saving effect can be further increased.

  According to the invention described in item (2) above, when a part unit including the driving object, for example, a toner cartridge is replaced, after a predetermined rotation or a predetermined time from the start of steady rotation of the toner stirring roller as the driving object. After the time, the initially hardened toner is agitated and the load of the toner agitation roller is reduced, so that the duty ratio of the pulse width modulation signal for the clutch is changed from the second value to a smaller value, The power consumption is further reduced.

  According to the invention described in item (3) above, if the driving object, for example, the toner stirring roller does not operate for a long time, the toner hardens and the load on the toner stirring roller increases. After the rotation or after a predetermined time, the toner is agitated and the load of the toner agitation roller is lightened. Therefore, the duty ratio of the pulse width modulation signal for the clutch is changed from the second value to a smaller value. Power consumption can be reduced.

  According to the invention described in the preceding item (4), when the component unit, for example, the fixing unit is replaced, the number of prints is 0 at the start of steady rotation of the fixing roller which is the driving target of the fixing unit. Since the load on the fixing roller is small, the duty ratio of the pulse width modulation signal to the clutch is set to the second value, so that power consumption is suppressed. Further, since the load on the fixing roller increases as the number of prints (the rotation amount of the fixing roller) increases, the duty ratio of the pulse width modulation signal is set to a second value according to the rotation amount of the fixing roller. As a result, the proper operation by the fixing roller is ensured.

  According to the invention described in (5) above, at the start of steady rotation of the driven object, the duty ratio of the pulse width modulation signal for the clutch is set to a second value smaller than the first value, and the power consumption Is suppressed. Further, since the duty ratio of the pulse width modulation signal can be changed a plurality of times in accordance with the load state of the driven object, it is possible to rationally reduce power consumption according to the load state of the driven object.

  According to the invention described in item (6) above, it is possible to perform appropriate power control of the clutch that drives the toner stirring roller of the toner cartridge.

  According to the invention described in item (7) above, it is possible to perform appropriate power control of the clutch that drives the fixing roller of the fixing unit.

  According to the invention described in the preceding item (8), the power consumption can be reduced compared to the conventional case where the maximum power is always supplied in accordance with the maximum load regardless of the load change of the driven object. Optimal clutch power control according to the load of the driven object can be performed, and the power saving effect can be further increased.

  According to the invention described in the preceding item (9), the power consumption can be reduced compared to the conventional case where the maximum power is always supplied in accordance with the maximum load regardless of the load change of the driven object. The power of the clutch can be optimally controlled according to the load of the driven object, and the computer of the image forming apparatus can execute a process that can increase the power saving effect.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating an electrical configuration of a main part of the image forming apparatus. It is a characteristic view showing the relationship between the duty ratio of the pulse width modulation signal and the driving torque. FIG. 10 is a characteristic diagram showing changes in clutch current and roller speed with respect to time in a conventional clutch control method using a PWM signal. In the clutch control method by the PWM signal in the embodiment of the present invention, it is a characteristic diagram showing the change of the clutch current and the roller speed with respect to time. (A) is a table showing the starting rotation time of the toner stirring roller and the duty ratio of the set pulse width modulation signal, and (B) is a table showing the starting rotation time of the fixing roller and the duty ratio of the set pulse width modulation signal. It is a table | surface which shows. (A) is a characteristic diagram showing the relationship between the load and rotation amount of the toner stirring roller during steady rotation, and (B) is a characteristic diagram showing the relationship between the duty ratio of the pulse width modulation signal and the rotation amount. It is a table | surface which shows an example of the setting value of a duty ratio in the case of changing the duty ratio of a pulse width modulation signal in normal rotation time. 6 is a flowchart showing a flow of clutch control processing by a pulse width modulation signal when a toner agitation roller is driven by a clutch. 11 is a flowchart showing a subroutine of a process (S3) of “starting rotation 1” in FIG. FIG. 11 is a flowchart showing a subroutine of a “steady rotation 1” process (S4) in FIG. 10. FIG. FIG. 11 is a flowchart illustrating a subroutine of a “stop time 1” process (S5) in FIG. 10. FIG. (A) is a characteristic diagram showing the relationship between the load on the fixing roller and the number of prints (fixing roller rotation amount) during steady rotation, and (B) is the duty ratio of the pulse width modulation signal and the number of prints (fixing roller rotation amount). It is a characteristic view which shows the relationship. 6 is a table showing a roller rotation amount, a roller load, a duty ratio of a set pulse width modulation signal, and a clutch driving force for each number of printed sheets in a fixing roller. 6 is a flowchart showing a flow of clutch control processing by a pulse width modulation signal when the fixing roller is driven by a clutch. FIG. 16 is a flowchart showing a subroutine of a “starting rotation time 2” process (S13) in FIG. 15; FIG. 16 is a flowchart showing a subroutine of “steady rotation 2” processing (S14) of FIG. FIG. 16 is a flowchart showing a subroutine of “stop time 2” processing (S15) in FIG. 15; FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to an embodiment of the present invention.

  In FIG. 1, when the image forming apparatus 101 is instructed to print, the sheet S as a recording medium stored in the sheet feeding tray 102 is taken out one by one by the sheet feeding roller 110a to the sheet feeding conveyance path 100 and conveyed. It is conveyed by rollers 110b and 110c.

  While the sheet S is conveyed, the charged photoreceptors 105a, 105b, 105c, and 105d are exposed by the laser unit 103 based on the image data. Then, the toner in each color developing unit 104a, 104b, 104c, 104d is developed to form a toner image on the photoconductors 105a, 105b, 105c105d, and a voltage is applied to the photoconductors 105a, 105b, 105c105d. Four color toner images of yellow (Y), magenta (M), cyan (C), and black (K) are transferred onto the intermediate transfer belt 106.

  Thereafter, the four color toner images formed on the intermediate transfer belt 106 are transferred onto the paper S by applying a voltage to the transfer roller 110d. The toner image formed on the sheet S is fixed on the sheet S by applying heat and pressure by passing between the fixing roller 11 and the pressure roller 12 of the fixing device (fixing unit) 108. The sheet S on which the toner image is fixed is discharged to a discharge tray (not shown) by discharge rollers 110e and 110e.

  When the image formation is performed and the toner in the developing units 104a, 104b, 104c, and 104d is reduced, the toner filled in the toner bottles (toner cartridges) 107a, 107b, 107c, and 107d for the respective colors is supplied to the developing units 104a, 104b, and 104d. 104c and 104d. Toner bottles (toner cartridges) 107a, 107b, 107c, and 107d are provided with toner stirring rollers 120a, 12b, 120c, and 120d, respectively.

  The main motor 109a is a rotational drive source for transporting the paper S from the paper feeding process to the transfer process. In addition, the main motor 109a drives the intermediate transfer belt 106 and the black photosensitive member 105d. The fixing motor 109b drives the fixing roller 11 via a clutch.

  Furthermore, the black developing motor 109c drives the black developing unit 104d.

  The color developing motor 109d drives yellow (Y), magenta (M), and cyan (C) developing units 104a, 104b, and 104c.

  Further, the color photoconductor motor 109e drives yellow (Y), magenta (M), and cyan (C) photoconductors 105a, 105b, and 105c.

  A black developing clutch and a color developing clutch may be used in place of the black developing motor 109c and the color developing motor 109d.

  The toner stirring rollers 120a, 12b, 120c, and 120d are also driven by a motor (not shown) via a clutch.

  Next, an embodiment in which the toner stirring rollers 120a, 12b, 120c, and 120d of the toner bottles 107a, 107b, 107c, and 107d and the fixing roller 11 of the fixing device 108 are controlled by the clutch 4 (FIG. 2) will be described.

  The toner bottles 107a, 107b, 107c, and 107d are filled with toner, and the load of the toner agitation rollers 120a, 12b, 120c, and 120d, which are objects to be driven by the clutch, changes with time depending on the toner state. This is a component unit that is replaced when the toner runs out. The fixing unit 108 is also a component unit that is replaced when the load of the fixing roller 11 as a driving object changes with time due to execution of printing and reaches the end of its life. The replaceable component unit is not limited to a toner bottle or a fixing device, and may be a developing unit including a developing roller that is a driving target and whose load changes with time.

  FIG. 2 is a block diagram illustrating an electrical configuration of a main part of the image forming apparatus.

  As shown in FIG. 2, the image forming apparatus includes a CPU 1 as a control unit, a RAM 2, a data storage unit 3, and a clutch 4. The CPU 1, the RAM 2, and the data storage unit 3 are control boards. 10 is implemented.

  In addition to overall control of the entire operation of the image forming apparatus 1, the CPU 1 controls the clutch 4 that controls driving of the toner stirring rollers 120a, 12b, 120c, 120d, the fixing roller 11, and the like as driving objects. In addition, a pulse width modulation signal (also referred to as a PWM signal) is applied, and a connection / release signal is transmitted to control connection / release of the clutch 4 and the transport rollers 110b and 110c. When the clutch 4 is connected, the toner stirring rollers 120a, 12b, 120c, 120d and the fixing roller 12 are rotated. On the other hand, when the clutch 4 is released, the toner stirring rollers 120a, 12b, 120c, 120d and the fixing roller 11 are stopped. Further, the CPU 1 has a timer function based on a clock, determines the timing for changing the duty ratio (also referred to as duty or duty) of the PWM signal, and makes the duty ratio variable so that it is input to the clutch 4. Controls the amount of voltage (amount of power).

  The RAM 2 is a memory that provides a work area when the CPU 1 operates.

  The data storage unit 3 detects and manages the toner bottles 107a, 107b, 107c, and 107d (not shown), the previous toner agitation time by the toner agitation rollers 120a, 12b, 120c, and 120d, and the fixing unit 108. Exchange information and various data such as the number of prints are stored, and these pieces of information are used when setting the duty ratio of the PWM signal.

  The clutch 4 controls driving of the toner agitation roller of the toner cartridge or the fixing roller 11 of the fixing device 108, for example.

  FIG. 3 is a characteristic diagram showing the relationship between the duty ratio of the PWM signal and the drive torque.

  In FIG. 3, the voltage value applied to the clutch 4 increases by increasing the duty ratio of the PWM signal, and further, the current flowing through the clutch 4 increases as the applied voltage of the clutch 4 increases, and the drive torque also increases. .

  FIG. 4 is a characteristic diagram showing changes in the clutch current and the roller speed with respect to time in the conventional clutch control method for driving and controlling the toner stirring rollers 120a, 12b, 120c, and 120d or the fixing roller 11.

  In FIG. 4, the time from 0 to t1 is the starting rotation time, and at time t1, the coupling of the clutch 4 to the roller is completed, and the roller starts steady rotation. The startup rotation time 0 to t1 is set in advance according to the actual machine specifications. The period from time t1 to t2 is the steady rotation time. In FIG. 4, the duty ratio of the PWM signal at the start rotation of the toner stirring rollers 120a, 12b, 120c, and 120d is set as shown in the table of FIG. 6A, and the PWM signal at the start rotation of the fixing roller 11 is set. A case is shown in which the duty ratio is set as shown in the table of FIG.

  FIGS. 6A and 6B are tables showing the set values of the starting rotation time of the toner stirring rollers 120a, 12b, 120c, and 120d and the fixing roller 11 and the duty ratio of the PWM signal based on the actual machine specifications. The numerical values shown in FIGS. 6A and 6B are stored in the data storage unit 3.

  In FIG. 6A, when the roller speed is 50 / min and the roller load is 0.04 [mN · m], the roller starting rotation time is 15 [ms], the duty ratio of the PWM signal is 34 [%], the clutch When the driving force is 0.10 [mN · m], the roller load is 0.10 [mN · m], the roller start-up rotation time is 20 [ms], the duty ratio of the PWM signal is 80 [%], The clutch driving force is 0.24 [mN · m]. On the other hand, also in FIG. 6B, the roller starting rotation time, the duty ratio of the PWM signal, and the clutch driving force are different values depending on the roller load.

  In the example of FIG. 4, the duty ratio of the PWM signal in the startup rotation time is maintained as it is even during the steady rotation time from time t1 to t2, and the clutch 4 is driven.

  FIG. 5 is a characteristic diagram showing changes in the clutch current and the roller speed with respect to time in the clutch control method according to this embodiment when driving and controlling the toner stirring rollers 120a, 12b, 120c, and 120d. In the clutch control method shown in FIG. 5, the control of the clutch 4 during the starting rotation time from time 0 to t1 is the same as that described in FIG. 4, and is performed with the setting as shown in FIG. 6 (A) or (B). Is called. However, the duty ratio of the PWM signal in the steady rotation time is set to a value half that of the duty ratio in the startup rotation time.

  Specifically, assuming that the duty ratio of the PWM signal of the starting rotation time is the first value, the second value smaller than the first value of the duty ratio of the PWM signal during the steady rotation time (example of FIG. 5). Then, as described above, it is set to 1/2 of the first value. The second value varies depending on the roller load. For example, in the tables of FIGS. 6A and 6B, different duty ratios (first values) are set according to the roller load, but the second value also becomes different values according to the roller load. When the first value is set to 34% at 0.04 mN · m, for example, 17% is set as the second value, and the first value is set to 80% at the roller load of 0.10 mN · m. For example, 40% is set as the second value.

  In this way, the duty ratio of the PWM signal of the clutch at the time of steady rotation is changed to a smaller value according to the load state of the driving object compared to the duty ratio at the time of starting rotation. Compared to the conventional case where the maximum power is always supplied according to the maximum load regardless of the power consumption, the power consumption of the clutch can be reduced and the optimum clutch power control according to the load of the driven object can be performed. This can increase the power saving effect.

  However, when the duty ratio of the PWM signal is the second value, the driving torque of the clutch 4 is required to be larger than the load torque of the toner stirring rollers 120a, 12b, 120c, 120d and the fixing roller 11.

  Note that the speeds of the toner stirring rollers 120a, 12b, 120c, 120d and the fixing roller 11 during the steady rotation time are not different between the conventional example of FIG. 4 and the present embodiment of FIG.

  Further, with respect to the rotation stop, the clutch current decreases earlier in the present embodiment of FIG. 5 than in the conventional example of FIG.

  FIG. 7 is for explaining another embodiment of the present invention. FIG. 7A is a characteristic diagram showing the relationship between the load and the rotation amount of the toner stirring rollers 120a, 12b, 120c, and 120d during the steady rotation time. FIG. 7B is a characteristic diagram showing the relationship between the duty ratio of the PWM signal and the rotation amount of the toner stirring roller.

  As shown in FIG. 7A, when the toner stirring by the toner stirring rollers 120a, 12b, 120c, and 120d is not performed for 24 hours or more, the toner is hardened and the load is increased. The solidified toner is crushed and the load is gradually reduced.

  Similarly, when a new toner bottle is used, the load is high at the start of toner stirring, and the load is gradually reduced by performing toner stirring.

  This phenomenon is related to the rotation amount of the toner stirring rollers 120a, 12b, 120c, and 120d. As shown in FIG. 7A, the toner stirring rollers 120a, 12b, 120c, and 120d reach a predetermined rotation amount. After that, the load becomes constant.

  Since the rotation speeds of the toner stirring rollers 120a, 12b, 120c, and 120d are constant, the predetermined rotation amount is synonymous with the predetermined time.

  In addition, since the load on the toner stirring rollers 120a, 12b, 120c, and 120d is reduced to a linear shape, in this embodiment, as shown in FIG. At time t3, the duty ratio of the PWM signal is decreased, the toner stirring roller further rotates halfway, and the load of the toner stirring roller becomes constant (time t4 after starting steady rotation). It is intended to reduce the duty ratio.

  FIG. 8 shows an example of the duty ratio setting value when the duty ratio of the PWM signal is changed during the steady rotation time.

  In FIG. 8, the toner stirring roller load is 0.10 [mN · m] at the start of steady rotation (the elapsed time from the start of steady rotation is 0 [s] and the rotation amount of the toner stirring roller is 0 [circumference]). The duty ratio of the PWM signal is set to 40%, and the clutch driving force at that time is 0.12 [mN · m]. At the time when half-circulation rotation has progressed (elapsed time t3 [s] from the start of steady rotation), the toner stirring roller load is 0.07 [mN · m], and the duty ratio of the PWM signal is reduced to 30%. The clutch driving force at that time is 0.09 [mN · m]. Further, at the time when the half-circulation rotation has advanced (elapsed time t4 [s] from the start of steady rotation), the toner stirring roller load is 0.04 [mN · m], and the duty ratio of the PWM signal is reduced to 17%. The clutch driving force at that time is 0.05 [mN · m].

  As described above, the CPU 1 that controls the clutch 4 by varying the duty ratio of the pulse width modulation signal has a set duty ratio value of the first value during the starting rotation time until the clutch 4 is completely engaged. However, the duty ratio of the pulse width modulation signal is set to a second value smaller than the first value after a predetermined time from the start of clutch driving or during a steady rotation time after a predetermined rotation. The toner bottles 107a, 107, 107c, and 107d are set to a value smaller than the second value depending on the state of the toner bottle being replaced, for example, the state in which the toner bottle has not been stirred for 24 hours or more. . Accordingly, the power consumption can be reduced correspondingly, and the optimum clutch power control can be performed according to the load of the toner stirring roller.

  FIG. 9 is a flowchart showing the flow of the clutch control process by the PWM signal when the toner stirring rollers 120a, 12b, 120c, and 120d are driven by the clutch 4.

  This control process is executed by the CPU 1 of the image forming apparatus operating according to a control program recorded on a recording medium such as the data storage unit 3.

  9, in step S1, load information and PWM signal duty ratio setting information stored in advance in the data storage unit 3 as parameters are read. In step S2, the clutch 4 is started. In step S3, the control process of “1 at start-up rotation” is performed. In step S4, the control process of “1 at the time of steady rotation” is performed. In step S5, the control process of “1 at stop rotation” is performed. To do.

  FIG. 10 is a flowchart showing a subroutine of the “starting rotation time 1” process (step S3 in FIG. 9).

  In FIG. 10, in step S31, it is determined whether or not the clutch 4 has been started. If the clutch 4 has not been started (NO in step S31), the process waits for the start. If activation of the clutch 4 is started (YES in step S31), the process proceeds to step S32.

  In step S32, it is determined whether or not the toner cartridge (toner bottle) has been replaced. If the toner cartridge has not been replaced (NO in step S32), in step S33, the toner agitation is left for a period of time during which the toner is not agitated. It is determined whether or not the time exceeds 24 hours. If the toner agitation standing time does not exceed 24 hours (NO in step S33), the PWM duty ratio is set to 34% in step S34, and the process proceeds to step S35. move on.

  If the toner cartridge has been replaced (YES in step S32), the process proceeds to step S36, and if the toner stirring time has exceeded 24 hours (YES in step S33), the process proceeds to step S36.

  In step S36, after setting the flag F = 1, in step S37, the duty ratio of the PWM signal is set to 80%, and the process proceeds to step S35.

  In step S35, it is determined whether or not the time t1 has been reached. In other words, it is determined whether or not the start-up rotation time has ended. If the time t1 has not been reached (NO in step S35), the time t1 is waited. When t1 is reached (YES in step S35), the process returns.

  FIG. 11 is a flowchart showing a subroutine of the process “step 1 at steady rotation” (step S4 in FIG. 9).

  In FIG. 11, in step S41, the duty ratio of the PWM signal is set to half, and in step S42, it is determined whether or not the flag F = 1. If the flag F is not 1 (NO in step S42), the process proceeds to step S47.

  If flag F = 1 (YES in step S42), it is determined in step S43 whether or not the roller has rotated half a circle. If the roller does not rotate half a circle (NO in step S43), it waits for a half rotation. If the roller is rotating half a circle (YES in step S43), in step S44, the duty ratio of the PWM signal is set to 30%, and then the process proceeds to step S45.

  In step S45, it is determined whether or not the roller has further rotated half a circle. If the roller has not further rotated half a circle (NO in step S45), the process waits as it is. If the roller has further rotated half a circle (YES in step S45), in step S46, the duty ratio of the PWM signal is set to 17%, and the process proceeds to step S47.

  In step S47, it is determined whether or not to stop the clutch. If the clutch is not stopped (NO in step S47), the process waits for the stop, and if the clutch is stopped (YES in step S47), the process returns. .

  FIG. 12 is a flowchart showing a subroutine of the “stop time 1” process (step S5 in FIG. 9).

  In FIG. 12, after the duty ratio of the PWM signal is set to 0% in step S51, the process returns.

  Next, another embodiment of the present invention will be described.

  FIG. 13A is a characteristic diagram showing the relationship between the load of the fixing roller 11 and the number of prints (fixing roller rotation amount) during steady rotation, and FIG. 13B is the duty ratio of the PWM signal and the number of prints (fixing). FIG. 6 is a characteristic diagram showing a relationship with a roller rotation amount). However, the number of prints is proportional to the rotation amount of the fixing roller.

  The fixing roller 11 is driven by a fixing motor through the clutch 4 and is used for fixing the transferred toner image on the printing paper S. As shown in FIG. The load increases as the number of sheets, that is, the number of fixed sheets of print paper S increases.

  This is because an impurity is generated in the fixing roller 11 every time the number of fixed sheets of the print paper S increases, and the load is increased due to the accumulation of the impurity.

  From this situation, as shown in FIG. 13B, when the number of printed sheets exceeds a certain amount, for example, p1 [sheets], p2 [sheets], the duty ratio of the PWM signal of the clutch 4 is set to a certain amount, for example, The p1 [sheet] is increased by 5%, and the p2 [sheet] is increased by 3%. The time when the number of printed sheets reaches p3 [sheets] is set as the replacement time of the fixing roller 11 or the fixing device 108 including the fixing roller 11. In this embodiment, the set value of the duty ratio of the PWM signal is set with reference to the table shown in FIG.

  The table of FIG. 14 shows the roller rotation amount [circumference], the roller load [mN · m], the set duty ratio [%] of the PWN signal, and the clutch driving force [mN · m] for each print number of the fixing roller 11. Yes.

  In FIG. 14, for example, when the number of printed sheets is p1 [sheets], the roller rotation amount, the roller load, the PWM duty ratio, and the clutch driving force are 1000 [circumference], 0.35 [mN · m], and 42 [%], respectively. ], 0.42 [mN · m].

  For example, when the number of printed sheets is p3 (sheets), the roller rotation amount, the roller load, the duty ratio of the PWM signal, and the clutch driving force are 25000 [circumference], 0.43 [mN · m], and 45 [%], respectively. 0.45 [mN · m].

  Thus, in this embodiment, with respect to the fixing roller 11 that is the object to be driven, the number of prints is 0 at the start of steady rotation after replacement of the fixing device 108, and the load on the fixing roller 11 is small. The duty ratio of the PWM signal to 4 is set to be relatively small, so that power consumption is suppressed. Further, since the load on the fixing roller 11 increases as the number of prints (the number of rotations) increases, an appropriate operation by the fixing device 108 is ensured by setting a large duty ratio of the PWM signal to the clutch 4. In addition, optimal clutch power control is performed in accordance with the load on the fixing roller 11.

  FIG. 15 is a flowchart showing the flow of the clutch control process using the PWM signal when the fixing roller 11 is driven by the clutch 4.

  This control process is executed by the CPU 1 of the image forming apparatus operating according to a control program recorded on a recording medium such as the data storage unit 3.

  In FIG. 15, in step S11, the print number information and PWM duty ratio setting information stored in advance as parameters in the data storage unit 3 are read, and in step S12, the clutch 4 is started. In step S13, the control process of “2 at startup rotation” is performed, the control process of “2 at steady rotation” is performed in step S14, and after the control process of “2 at stop" is performed in step S15, the process is finished. To do.

  FIG. 16 is a flowchart showing a subroutine of the “starting rotation time 2” process (step S13 in FIG. 15).

  In FIG. 16, in step S131, it is determined whether or not the clutch 4 has been started. If the clutch 4 has not been started (NO in step S131), the process waits for the start. If activation of the clutch 4 is started (YES in step S131), the process proceeds to step S132.

  In step S132, it is determined whether or not the number of prints is less than p1, and if the number of prints is less than p1 (YES in step S132), flag F = 2 is set in step S139, and the duty ratio of the PWM signal is set to 74 in step S140. After setting to%, the process proceeds to step S136.

  If the number of prints is not less than p1 (NO in step S132), it is determined in step S133 whether the number of prints is less than p2 or not. If the number of prints is not less than p2 (NO in step S133), a flag is set in step S134. After setting F = 4 and setting the duty ratio of the PWM signal to 90% in step S135, the process proceeds to step S136.

  If the number of prints is less than p2 (YES in step S133), the flag F is set to 3 in step S137, the duty ratio of the PWM signal is set to 84% in step S380, and the process proceeds to step S136.

  In step S136, it is determined whether or not the time t1 has been reached. In other words, it is determined whether or not the startup rotation time has ended. If the time t1 has not been reached (NO in step S136), the time t1 is waited for, If YES (YES in step S136), the process returns.

  FIG. 17 is a flowchart showing a subroutine of the process “2 at steady rotation” (step S14 in FIG. 15).

  In FIG. 17, in step S141, the duty ratio of the PWM signal is set to half, and in step S142, it is determined whether or not the number of prints = p1. If the number of prints is not p1 (NO in step S142), step S143 is determined. Proceed to If the number of prints = p1 (YES in step S142), the duty ratio of the PWM signal is set to 42% in step S146, and then the process proceeds to step S143.

  In step S143, it is determined whether the number of prints = p2, and if the number of prints = p2 is not satisfied (NO in 143), the process proceeds to step S144. If the number of prints = p2 (YES in step S143), the duty ratio of the PWM signal is set to 45% in step S147, and the process proceeds to step S144.

  In step S144, it is determined whether or not the number of prints = p3. If the number of prints = p3 (YES in step S144), the process directly returns. If the number of prints = p3 is not satisfied (NO in step S144), the process proceeds to step S145. move on.

  In step S145, it is determined whether or not to stop the clutch. If the clutch is not stopped (NO in step S145), the process returns to step S142. If the clutch is stopped (YES in step S145), the process returns.

  FIG. 18 is a flowchart showing a subroutine of the “stop time 2” process (step S15 in FIG. 15).

  In FIG. 18, in step S151, after the duty ratio of the PWM signal is set to 0%, the process returns.

1 CPU
4 Clutch 5 Time-detected state detection unit 11 Fixing roller 108 Fixing device 107a, 107b, 107c, 107d Toner bottle (toner cartridge)
120a, 12b, 120c, 120d Toner stirring roller

Claims (9)

A clutch that drives and controls a driving object whose load changes with time by receiving power supply from a power source;
The clutch is controlled by the duty ratio of the pulse width modulation signal, and the duty ratio of the pulse width modulation signal is set to a first value at the time of start-up rotation until the clutch is completely connected to the driving object. Control means for changing the duty ratio of the pulse width modulation signal to a second value smaller than the first value according to a load state of the driving object during steady rotation after completion;
An image forming apparatus comprising:   When the component unit including the driving object is replaced, the control means sets the duty ratio of the pulse width modulation signal to a second value after a predetermined rotation or a predetermined time from the start of steady rotation of the driving object. The image forming apparatus according to claim 1, wherein the value is changed from a value to a smaller value.   When the driving object is not operated for a predetermined time, the control means changes the duty ratio of the pulse width modulation signal from the second value after a predetermined rotation or a predetermined time from the start of steady rotation of the driving object. The image forming apparatus according to claim 1, wherein the image forming apparatus is further changed to a smaller value.   The control means changes the duty ratio of the pulse width modulation signal to the second value at the start of steady rotation when the component unit including the drive object is replaced, and the rotation amount of the drive object The image forming apparatus according to claim 1, wherein the duty ratio of the pulse width modulation signal during steady rotation is increased according to.   The control means changes the duty ratio of the pulse width modulation signal to the second value at the start of steady rotation, and then changes the duty ratio of the pulse width modulation signal a plurality of times according to the load state of the driven object. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 2, wherein the component unit is a toner cartridge filled with toner, and the driving target is a toner stirring roller.   The image forming apparatus according to claim 4, wherein the component unit is a fixing unit, and the driving object is a fixing roller. A method of controlling the clutch in an image forming apparatus including a clutch that controls driving of a driving object whose load changes with time by receiving power supply from a power source,
The clutch is controlled by the duty ratio of the pulse width modulation signal, and the duty ratio of the pulse width modulation signal is set to the first value at the time of start-up rotation until the clutch is connected, and the steady rotation after the connection is completed In some cases, the image forming method includes a control step of changing a duty ratio of the pulse width modulation signal to a second value smaller than the first value in accordance with a load state of the driven object. A clutch control method in an apparatus. A clutch control program for causing a computer of an image forming apparatus provided with a clutch to drive and control a driving object whose load changes with time by receiving power supply from a power source,
The program is
The clutch is controlled by the duty ratio of the pulse width modulation signal, and the duty ratio of the pulse width modulation signal is set to the first value at the time of start-up rotation until the clutch is connected, and the steady rotation after the connection is completed Sometimes, the clutch control program causes the computer to execute a control step of changing the duty ratio of the pulse width modulation signal to a second value smaller than the first value in accordance with a load state of the driven object. .

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