JP2013148696A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of detecting abnormality of a transmission member for transmitting driving force to a rotatable member of a developing device.SOLUTION: A printer has a first mode in which a transmission member transmits a driving force to rotate a rotatable member with a first rotational speed, and a second mode in which the transmission member rotates the rotatable member with a second rotational speed (<the first rotational speed); and switches the modes as required. The printer measures downtime of a drive motor after an instruction to switch to the second mode has issued, and determines whether or not abnormality has occurred to the transmission member on the basis of the downtime.

Description

  The present invention relates to an image forming apparatus.

  Conventionally, in an image forming apparatus in which a developing device forms a developer image and transfers the developer image onto a sheet, a driving force output from a driving source such as a motor is applied to a developing roller, a developer supply roller, or Some are provided with a clutch that transmits to a rotating member such as a developer conveying member. The image forming apparatus can switch between a state where the driving force is transmitted to the rotating member and a state where the driving force is not transmitted to the rotating member by controlling the clutch. In such an image forming apparatus, for example, when image formation is unnecessary, such as cleaning of a photoreceptor, the clutch is controlled so that the driving force is not transmitted to the rotating member of the developing device, so that the developer is deteriorated at an early stage. Can be suppressed.

  As a transmission member that transmits the driving force to the rotating member, for example, in Patent Document 1, the driving force from the clutch 200 that transmits the driving force from the driving source 400 to the developer conveying roller 105 or the driving force from the photosensitive member driving motor 122 is developed. A developing roller driving clutch 19 for transmitting to the roller 11 is disclosed.

JP-A-9-146369

  However, the conventional image forming apparatus described above has the following problems. In other words, if the clutch breaks down in a state where the driving force is transmitted to the rotating member, the clutch state is not switched even after a command for switching the driving force to the rotating member is not issued, and the driving force is transmitted to the rotating member. Will continue to do. In this case, since it is possible to form an image although it is a failure, it is difficult to detect a failure that cannot be switched to a state in which the driving force is not transmitted to the rotating member. If the driving force continues to be transmitted to the rotating member, the developer becomes excessively stressed, which may cause early deterioration of the developer. Further, when foreign matter is mixed in the clutch, an abnormality that cannot be switched to a state in which the driving force is not transmitted to the rotating member occurs. Furthermore, if the signal line for energizing the clutch is disconnected, an abnormality that cannot be switched to a state in which the driving force is transmitted to the rotating member occurs.

  The present invention has been made to solve the problems of the conventional image forming apparatus described above. That is, an object of the present invention is to provide an image forming apparatus capable of detecting an abnormality of a transmission member that transmits a driving force to a rotating member of a developing device.

  An image forming apparatus for solving this problem includes a drive motor that rotationally drives a rotating member that conveys developer, a transmission member that transmits a driving force that rotationally drives the rotating member, and the rotation member. A first mode in which the transmission member transmits a driving force for rotating the rotating member at a first rotational speed; and a driving force for the transmission member to rotate the rotating member at a second rotational speed that is slower than the first rotational speed. The switching unit that switches between the second mode to be transmitted, the control unit that controls the rotational speed of the drive motor, and the drive after the control unit starts the control to reduce the rotational speed of the drive motor to a predetermined speed. A detection unit for detecting the rotation speed of the motor, a rotation speed when detected by the detection unit after the command to switch to the first mode is issued, and a command to switch to the second mode And a determination unit that determines whether or not an abnormality has occurred in the transmission member based on the rotation speed detected by the detection unit after being output.

  In the image forming apparatus according to the present invention, the transmission member transmits a driving force for rotating the rotation member at the first rotation speed, and the transmission member rotates the rotation member at the second rotation speed (<first rotation speed). And a second mode for transmitting the driving force to be transmitted. Examples of the rotating member that conveys the developer include a developing roller, a developer supply roller, and a stirring member. Moreover, as a transmission member which can change the rotational speed of a rotation member, a transmission mechanism and a clutch correspond, for example. Further, the second mode includes a state in which the rotation member is in a rotation stopped state, that is, a state in which the second rotation speed is zero. In the image forming apparatus of the present invention, as a failure inspection of the transmission member, the rotational speed of the drive motor when detected after the command to switch to the first mode is issued and the command to switch to the second mode are issued. Based on the rotation speed of the drive motor detected later, it is determined whether or not an abnormality has occurred in the transmission member.

  That is, since the load resistance of the transmission member is different between the first mode and the second mode, if the transmission member is normal, the rotational speed of the drive motor when detected after a command to switch to the first mode is issued. The rotational speed of the drive motor detected after the command to switch to the second mode is different. On the other hand, if there is an abnormality in the transmission member and the transmission member cannot be switched to the second mode, that is, even after a command to switch to the second mode is issued, the rotating member rotates at the first rotational speed. When continuing, the rotational speed equivalent to the rotational speed of the drive motor detected in the state of the first mode is detected. Further, when there is an abnormality in the transmission member and the transmission member cannot be switched to the first mode, that is, even after a command to switch to the first mode is issued, the rotating member rotates at the second rotational speed. When continuing, the rotational speed equivalent to the rotational speed of the drive motor detected in the state of the 2nd mode is detected. Therefore, in the image forming apparatus of the present invention, the rotational speed of the drive motor when it is detected after the command for switching to the first mode is issued, and the drive motor detected after the command for switching to the second mode is issued. Based on the rotational speed, it can be determined whether or not an abnormality has occurred in the transmission member.

  The image forming apparatus of the present invention further includes a measuring unit that measures a time from when the deceleration control is started until the rotational speed detected by the detecting unit reaches the predetermined speed, and the determining unit Is a time when measured by the measurement unit after a command to switch to the first mode is issued, and a time measured by the measurement unit after a command to switch to the second mode is issued, If the difference is within a predetermined time, it may be determined that an abnormality has occurred in the transmission member.

  That is, as a failure inspection of the transmission member, after a command to switch to the second mode is issued, the time for the rotation speed of the drive motor to be reduced to a predetermined speed is measured, and after that command to switch to the first mode is issued It may be determined that an abnormality has occurred when the difference from the measured time is within a predetermined time.

  That is, when the rotational speed of the drive motor is decelerated to a predetermined speed as the second mode, the load resistance of the transmission member is different between the first mode and the second mode. In this state, a time different from the time during which the rotational speed of the drive motor is reduced to a predetermined speed is measured. On the other hand, if there is an abnormality in the transmission member and the transmission member cannot be switched to the second mode, that is, even after a command to switch to the second mode is issued, the rotating member rotates at the first rotational speed. When continuing, the time equivalent to the time for the rotational speed of the drive motor to decelerate to a predetermined speed in the state of the first mode is measured. Further, when there is an abnormality in the transmission member and the transmission member cannot be switched to the first mode, that is, even after a command to switch to the first mode is issued, the rotating member rotates at the second rotational speed. When continuing, the time equivalent to the time for the rotational speed of the drive motor to decelerate to a predetermined speed in the state of the second mode is measured. Therefore, in the image forming apparatus of the present invention, after the command to switch to the second mode is issued, the time for the rotational speed of the drive motor to decelerate to the predetermined speed is measured, and the command to switch to that time and the first mode is issued. It can be determined that an abnormality has occurred when the difference from the time measured later is within a predetermined time.

  In the image forming apparatus according to the aspect of the invention, the determination unit may include the time when the measurement unit measures in the first mode and the measurement unit after a command to switch to the second mode is issued. When the difference between the measured time and the time is within a predetermined time, it may be determined that an abnormality that cannot be switched from the first mode to the second mode has occurred in the transmission member. That is, the time during which the measured rotational speed of the drive motor is reduced to a predetermined speed after the command for switching to the second mode is issued, the rotational speed of the drive motor measured in the first mode is reduced to the predetermined speed. If the time is equal to the time, it can be determined that the state is not in the second mode and the transmission member continues to operate in the first mode.

  In the image forming apparatus according to the aspect of the invention, the determination unit may measure the time measured by the measurement unit after the command to switch to the first mode is issued and the command to switch to the second mode. When the difference from the time measured by the measurement unit is within a predetermined time, it may be determined that an abnormality has occurred. That is, the time during which the rotational speed of the drive motor measured after the command to switch to the first mode is reduced to the predetermined speed is the rotational speed of the drive motor measured after the command to switch to the second mode is issued. If the time is equivalent to the time to decelerate to the predetermined speed, it can be determined that an abnormality has occurred in the transmission member.

  The image forming apparatus of the present invention further includes a measuring unit that measures a time from when the deceleration control is started until the rotational speed detected by the detecting unit reaches the predetermined speed, and the determining unit The difference between the time measured by the measurement unit after the command to switch to the first mode and the time measured by the measurement unit in the second mode is a predetermined time If it is within the range, it may be determined that an abnormality that cannot be switched from the second mode to the first mode has occurred in the transmission member. That is, the time during which the measured rotational speed of the drive motor is decelerated to a predetermined speed after the command to switch to the first mode is issued is reduced to the predetermined speed when the rotational speed of the drive motor is measured in the second mode. If the time is equal to the time, it can be determined that the first mode is not established and the transmission member continues to operate in the second mode.

  In the image forming apparatus according to the aspect of the invention, the detection unit detects the rotation speed when a predetermined time has elapsed since the start of the deceleration control, and the determination unit is configured to issue a command to switch to the first mode. The difference between the rotation speed when detected by the detection unit after being issued and the rotation speed detected by the detection unit after a command to switch to the second mode is issued is a predetermined speed. And a determination unit that determines that an abnormality has occurred in the transmission member.

  That is, when the rotational speed of the drive motor is decelerated to a predetermined speed as the second mode, the load resistance of the transmission member is different between the first mode and the second mode. A rotational speed different from the rotational speed detected when a predetermined time has elapsed after the deceleration control is started in the state is detected. On the other hand, if there is an abnormality in the transmission member and the transmission member cannot be switched to the second mode, that is, even after a command to switch to the second mode is issued, the rotating member rotates at the first rotational speed. When continuing, the rotational speed equivalent to the rotational speed detected when the predetermined time has passed after the deceleration control is started in the state of the first mode is detected. Further, when there is an abnormality in the transmission member and the transmission member cannot be switched to the first mode, that is, even after a command to switch to the first mode is issued, the rotating member rotates at the second rotational speed. When continuing, the rotational speed equivalent to the rotational speed detected when the predetermined time has passed since the deceleration control is started in the state of the second mode is detected. Therefore, in the image forming apparatus of the present invention, the rotational speed detected when a predetermined time has elapsed after the start of the deceleration control after the command to switch to the second mode is issued, and the command to switch to the first mode. It can be determined that an abnormality has occurred when the difference from the time detected after detection is within a predetermined time.

  In the image forming apparatus according to the aspect of the invention, the detection unit detects the rotation speed when a predetermined time has elapsed since the start of the deceleration control, and the determination unit is configured to issue a command to switch to the first mode. When the difference between the rotation speed detected by the detection unit after the error is detected and the rotation speed detected by the detection unit in the state of the second mode is within a predetermined speed. And a determination unit that determines that an abnormality that cannot be switched from the second mode to the first mode has occurred in the transmission member. That is, the rotational speed of the drive motor detected when a predetermined time has elapsed since the start of the deceleration control after the command for switching to the first mode is issued, and after the deceleration control is started in the second mode. If the rotational speed is the same as the rotational speed of the drive motor detected when a predetermined time has elapsed, the first mode is not established and the transmission member continues to operate in the second mode. It can be judged.

  Specifically, a fixing roller that fixes the toner transferred onto the recording paper to the recording paper, a heating unit that heats the fixing roller, and a temperature control unit that controls the temperature of the fixing roller. The temperature control unit may maintain the temperature of the fixing roller at a predetermined temperature when the time is measured by the measurement unit. That is, since the rotational speed of the drive motor is affected by temperature conditions, it is preferable to suppress the influence by maintaining the temperature of the fixing roller at a predetermined temperature. More accurate fault inspection is possible.

  The image forming apparatus according to the present invention may further include a notification unit that notifies the user of information related to the abnormality when the determination unit determines that the abnormality is present. The information regarding the abnormality corresponds to, for example, the occurrence of an abnormality in the transmission member. The notification method includes, for example, lighting of an error lamp, error message to the liquid crystal panel, voice guidance, and mail transmission. By notifying the user (including service personnel) of the abnormality as in this configuration, it can be expected that the user can grasp the abnormality of the device at an early stage.

  Moreover, the said switching part is made into the state which does not transmit a driving force to the said rotation member as said 2nd mode, and it is good to stop rotation of the said rotation member. Since the second rotation speed is 0 and the load resistance of the transmission member is smaller in the second mode than in the first mode, if the transmission member is normal, the rotation speed of the drive motor detected in the state of the first mode is obtained. Slow rotation speed is detected.

  The predetermined speed may be a speed at which the rotational speed of the drive motor stops. It can be determined whether or not an abnormality has occurred in the transmission member by using the rotation speed when the rotation speed of the drive motor is decelerated and stopped.

  According to the present invention, an image forming apparatus capable of detecting an abnormality of a transmission member that transmits a driving force to a rotating member of a developing device is realized.

FIG. 2 is a diagram illustrating a schematic configuration of an image forming unit of a printer. FIG. 2 is a block diagram illustrating an electrical configuration of the printer illustrated in FIG. 1. FIG. 2 is a diagram illustrating a schematic configuration of a process unit of the printer illustrated in FIG. 1. It is a flowchart which shows the procedure of the inspection process concerning 1st Embodiment. 5 is a flowchart showing a procedure of stop time measurement processing (after a first mode switching command) shown in FIG. 4. 6 is a flowchart showing a procedure of stop time measurement processing (after a second mode switching command) shown in FIG. 4. It is a flowchart which shows the procedure of the abnormality determination process shown in FIG. It is a figure which shows the relationship between the rotational speed of the drive motor after the rotation stop command concerning 1st Embodiment, and time. It is a flowchart which shows the procedure of the test | inspection process concerning 2nd Embodiment. 10 is a flowchart showing a procedure of a rotational speed measurement process (after a first mode switching command) shown in FIG. 9. 10 is a flowchart showing a procedure of a rotational speed measurement process (after a second mode switching command) shown in FIG. 9. 10 is a flowchart illustrating a procedure of abnormality determination processing illustrated in FIG. 9. It is a figure which shows the rotational speed of the drive motor after the rotation stop command concerning 2nd Embodiment, and the relationship of time. It is a flowchart which shows the procedure of the test | inspection process concerning another Example.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Embodiments of an image forming apparatus according to the invention will be described below in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to an electrophotographic printer having a color printing function.

[Configuration of printer image forming unit]
The configuration of the image forming unit 10 of the printer 100 will be described with reference to FIG. The image forming unit 10 forms a toner image by electrophotography, transfers the toner image to a sheet, a fixing unit 8 that fixes unfixed toner on the sheet, and a sheet before image transfer. A paper feed tray 91 for placing paper and a paper discharge tray 92 for placing paper after image transfer are provided.

  In addition, the image forming unit 10 includes an exposure device 53 that irradiates each process unit 50C, 50M, 50Y, and 50K with light, and a conveyance belt 7 that conveys a sheet to the transfer position of each process unit 50C, 50M, 50Y, and 50K. It has.

  In the image forming unit 10, the paper stored in the paper feed tray 91 located at the bottom passes through the paper feed roller 71, the registration roller 72, the process unit 50, and the fixing device 8 and passes through the paper discharge roller 76. A substantially S-shaped conveyance path 11 (a chain line in FIG. 1) is provided so as to be guided to the upper discharge tray 92.

  The process unit 50 is capable of forming a color image, and process units corresponding to cyan (C), magenta (M), yellow (Y), and black (K) colors are arranged in parallel. Specifically, a process unit 50C that forms a C color image, a process unit 50M that forms an M color image, a process unit 50Y that forms a Y color image, and a process unit that forms a K color image 50K. In the paper transport direction, the process units 50C, 50M, 50Y, and 50K are arranged at equal intervals in this order from the downstream side. Note that the order of the process units is not limited to this.

  FIG. 3 shows a schematic configuration of the process unit 50K. The process unit 50K includes a drum-shaped photoconductor 1, a charging device 2 that uniformly charges the surface of the photoconductor 1, a developing device 4 that develops the electrostatic latent image with toner, And a transfer device 5 for transferring the toner image to a sheet. The photoreceptor 1 and the transfer device 5 are disposed in contact with the transport belt 7. The photosensitive member 1 is opposed to the transfer device 5 with the conveyance belt 7 interposed therebetween. The other process units 50C, 50M, and 50Y have the same configuration as the process unit 50K.

  Further, the developing device 4 includes a case 44 that accommodates toner as a developer, a developing roller 41 (an example of a rotating member) that faces the photoconductor 1 and conveys the toner in the case 44 to the photoconductor 1, and development. A supply roller 42 (an example of a rotating member) that supplies toner to the roller 41 and an agitator 43 (an example of a rotating member) that stirs the toner accumulated in the case 44 are provided. The developing roller 41 is provided so as to be able to come into contact with and separate from the photosensitive member 1 and is controlled so as to come into pressure contact with the photosensitive member 1 when an image is formed and away from the photosensitive member 1 when the photosensitive member 1 is cleaned. The agitator 43 has a toner agitating function and also a toner conveying function.

  The rotating members of the developing roller 41, the supply roller 42, and the agitator 43 located in the case 44 rotate by obtaining a rotational driving force from the driving motor 45. An electromagnetic clutch 46 (an example of a transmission member) that switches between a state in which the driving force is transmitted and a state in which the driving force is not transmitted is provided in the driving force transmission path from the driving motor 45 to each rotating member. . The electromagnetic clutch 46 is in a state of transmitting driving force by excitation. The drive motor 45 and the electromagnetic clutch 46 are controlled by the control unit 30.

  The rotational speed of the drive motor 45 is controlled by an FG sensor (Frequency Generator) (not shown). The FG sensor is a so-called power generation type sensor, and an FG signal having a frequency corresponding to the rotational speed of the drive motor 45 is output from the FG sensor. That is, when the rotation speed is high, the frequency of the output signal is high, and on the contrary, when the rotation speed is low, the frequency is low.

  In the following description, the state where the electromagnetic clutch 46 transmits the driving force is referred to as a “first mode”, and the state where the electromagnetic clutch 46 does not transmit the driving force is referred to as a “second mode”. The drive motor 45 and the electromagnetic clutch 46 may be shared by the process units 50K, 50C, 50M, and 50Y, or may be provided for each of the process units 50K, 50C, 50M, and 50Y. In this embodiment, the drive motor 45 is shared by the process units 50K, 50C, 50M, and 50Y, and the electromagnetic clutch 46 is provided for each of the process units 50K, 50C, 50M, and 50Y.

  In each of the process units 50C, 50M, 50Y, and 50K, the surface of the photoreceptor 1 is uniformly charged by the charging device 2. Then, it exposes with the light from the exposure apparatus 53, and an electrostatic latent image is formed. Next, toner is supplied to the photoreceptor 1 via the developing device 4. As a result, the electrostatic latent image on the photoreceptor 1 is visualized as a toner image.

  The image forming unit 10 takes out the sheets placed on the sheet feeding tray 91 one by one, and conveys the sheets onto the conveyance belt 7. Then, the toner image formed by the process unit 50 is transferred to the paper. At this time, in color printing, toner images are formed by the process units 50C, 50M, 50Y, and 50K, and the toner images are superimposed on the paper. On the other hand, in monochrome printing, a toner image is formed only by the process unit 50K and transferred to paper.

  The fixing device 8 includes a fixing roller 81, a pressure roller 82, a heater 83, a temperature sensor 84, and the like. The heater 83 is controlled such that the temperature measured by the temperature sensor 84 is maintained at the fixing target temperature, and thermal fixing is performed. The temperature sensor 84 is composed of a resistor, a thermistor, etc. (not shown). The thermistor is a resistor having a large electrical resistance change with respect to a temperature change, and is disposed in the vicinity of the heater 83. When the sheet on which the toner image has been transferred is conveyed to the fixing device 8, the fixing device 8 thermally fixes the toner to the sheet while the sheet passes between the fixing roller 81 and the pressure roller 82. The sheet on which the toner has been thermally fixed is discharged to a discharge tray 92.

  The conveyor belt 7 is an endless belt member wound around the conveyor rollers 73 and 74, and is made of a resin material such as polycarbonate. The conveyance belt 7 circulates and moves counterclockwise as the conveyance roller 74 is driven to rotate. Thus, the sheet placed on the upper surface is conveyed from the registration roller 72 side to the fixing device 8 side. Further, the conveyance roller 73 rotates following the movement of the conveyance belt 7.

[Electrical configuration of printer]
As shown in FIG. 2, the printer 100 according to the embodiment includes a control unit 30 (switching unit, determination unit) including a CPU 31, a ROM 32, a RAM 33, an NVRAM (Non Volatile RAM) 34, and a network interface 36. , An example of a second determination unit). In addition, the control unit 30 includes an image forming unit 10 that forms an image on a sheet, a temperature sensor 84 that measures the temperature of the fixing roller 81, and an operation panel 40 that displays an operation status and accepts an input operation by a user. An example of a notification unit is electrically connected.

  The CPU 31 executes arithmetic operations for realizing various functions such as a printing function and an inspection function described later, and is the center of control. The ROM 32 stores various control programs for controlling the printer 100, various settings, initial values, and the like. The RAM 33 is used as a work area from which various control programs are read or as a storage area for temporarily storing image data. The NVRAM 34 is a non-volatile storage means and is used as a storage area for storing various settings or image data.

  The CPU 31 stores each processing result in the RAM 33 or the NVRAM 34 in accordance with a control program read from the ROM 32 or signals sent from various sensors, and turns on each component of the printer 100 (for example, lighting of an exposure device constituting the image forming unit 10). The timing and the driving motor 45 of various rotating members constituting the developing device, and the electromagnetic clutch 46) for transmitting the driving force of the driving motor 45 to the rotating member are controlled.

  The network interface 36 is connected to a network and enables connection with other information processing apparatuses. Data communication with an external device can be performed via the network interface 36.

[Electromagnetic clutch inspection process]
Next, an inspection process (an example of a switching unit, a measurement unit, and a determination unit) for inspecting the electromagnetic clutch 46 will be described with reference to the flowchart of FIG. The inspection process is executed by the control unit 30 of the printer 100 at a timing when the power of the printer 100 is turned on, a timing when the number of times of printing reaches a predetermined number of times (for example, 1000 sheets are printed), and the like.

  Normally, the electromagnetic clutch 46 is set to the first mode to rotate the rotating members (the developing roller 41, the supply roller 42, and the agitator 43) during the printing process of the printer 100, and the rotation from the drive motor 45. Transmits driving force. When the printing process is completed, the electromagnetic clutch 46 is set to the second mode, and the rotational driving force from the drive motor 45 is not transmitted.

  When the inspection process is started and the warm-up or printing process is performed (S101), the stop time of the first drive motor 45 is measured after the process is completed (S102). When the warm-up or printing process is performed after the stop time is measured in S102 (S103), the stop time of the second drive motor 45 is measured after the process is completed (S104). When the second stop time is measured, a process for determining an abnormality in the electromagnetic clutch 46 is performed using the measured stop time (S105).

  When the first stop time measurement in S102 is performed, the stop time measurement process of the flowchart shown in FIG. 5 is performed. The measurement of the first stop time will be described with reference to the flowchart of FIG.

  When the stop time measurement process is started, the temperature control of the fixing device 8 is maintained for the stop time measurement process (S201). That is, the control that has been controlled so that the temperature of the fixing device 8 is stably maintained at the target temperature by the warm-up or printing process performed immediately before is continued. Next, a command for switching the electromagnetic clutch 46 to the state of the first mode is issued (S202, an example of a switching unit). Note that the temperature measured by the temperature sensor 84 at this time is equal to or higher than the rotatable temperature of the fixing roller 81. That is, the electromagnetic clutch 46 is controlled so that the driving force from the driving motor 45 is transmitted to each rotating member of the developing device 4.

  Next, control is performed so that the rotation of the motor rotates stably at the target speed (S203). The target speed is a rotational speed at which each rotating member can obtain a rotational driving force necessary for the printing process. Next, it is determined whether or not the temperature of the fixing device 8 has reached the target temperature (S204, an example of a setting unit). In S204, the temperature of the fixing motor 8 is controlled so as to be stably maintained at the target temperature before measuring the rotation stop time TE1 when the rotation of the drive motor 45 is stopped. The effect of differences can be reduced. Since the drive motor 45 has different driving characteristics due to the influence of temperature, if the temperature differs between the first measurement and the second measurement during the measurement of the stop time, the result of the stop time is affected. If it is determined that the target temperature has not been reached (S204: No), the process waits until the target temperature is reached. If it is determined that the target temperature has been reached (S204: Yes), a rotation stop command for stopping the rotation of the drive motor 45 is issued in order to measure the stop time TE1 during which the rotation of the drive motor 45 stops (S205). .

  When a rotation stop command is issued in S205, measurement of the stop time TE1 is started (S206). In the measurement of the stop time TE1, the measurement is performed until the rotation of the drive motor 45 is stopped. The stop of the drive motor 45 is determined by whether or not the FG signal output from the FG sensor is detected for a predetermined time. If the FG signal is not detected for a predetermined time, it is determined that the drive motor 45 has stopped. If it is determined that the drive motor 45 has stopped, the measurement of the stop time TE1 of the drive motor 45 is terminated (S207). Next, a command to switch to the second mode is issued (S208), and the processing of the flowchart of the stop time measurement processing in FIG.

  Subsequently, when the second stop time measurement in S104 is performed, the stop time measurement process of the flowchart shown in FIG. 6 is performed. The measurement of the second stop time will be described with reference to the flowchart of FIG. The difference from the first stop time measurement is that the mode of the electromagnetic clutch 46 during the stop time measurement is not the first mode but the second mode. Therefore, the same reference numerals as those in FIG.

  If it is determined in S204 that the target temperature has been reached (S204: Yes), a command to switch the electromagnetic clutch 46 from the first mode to the second mode is issued (S301). After the command to switch to the second mode is issued, a rotation stop command for stopping the rotation of the drive motor 45 is issued in order to measure the stop time TE2 in which the rotation of the drive motor 45 stops (S302).

  When a rotation stop command is issued in S302, measurement of the stop time TE2 is started (S303). In the measurement of the stop time TE2, the measurement is performed until the rotation of the drive motor 45 is stopped. If it is determined that the drive motor 45 has stopped, the measurement of the stop time TE2 of the drive motor 45 is ended (S304), and the process of the flowchart of the stop time measurement process in FIG. 6 is ended.

  When the second stop time measurement process in S104 is completed, an abnormality determination process for the electromagnetic clutch 46 in S105 is performed. The abnormality determination process will be described with reference to the flowchart shown in FIG.

  When the abnormality determination process is started, a time difference TEA between the measured stop time TE1 and stop time TE2 is calculated (S305). If the electromagnetic clutch 46 can normally switch between the first mode and the second mode, a time difference TEA as shown in FIG. 8 is calculated. Next, it is determined whether or not the time difference TEA is smaller than a predetermined value TS (S306, an example of a determination unit). The predetermined value TS is set to a time difference between the stop time TE1 and the stop time TE2 at which it can be determined that the electromagnetic clutch 46 operates normally. If an abnormality has occurred in the electromagnetic clutch 46, for example, if it is not possible to switch from the first mode to the second mode, the stop time TE2 was measured by switching to the second mode in S301. The clutch 46 is not switched to the second mode, and the stop time TE2 is measured in the state of the first mode. Therefore, the time difference TEA with respect to the stop time TE1 is a value substantially close to zero. In S306, it is determined that the time difference TEA is smaller than the predetermined value TS (S306: Yes), and that the electromagnetic clutch 46 is abnormal, the operation panel 40 and the like (S307, an example of a notification unit). When it is determined that the time difference TEA is larger than the predetermined value TS (S306: No), it is determined that the electromagnetic clutch 46 is normal, and the inspection process of this flowchart ends.

[Second Embodiment]
9 to 13 show a second embodiment. The difference from the first embodiment is that the stop time of the drive motor 45 is measured in the first embodiment after the rotation stop command for stopping the rotation of the drive motor 45 is issued, whereas the second embodiment is different from the first embodiment. In the example, the rotational speed of the drive motor 45 is measured. The rotation speed is measured at a point in time when a predetermined time T has elapsed since the rotation stop command for stopping the rotation of the drive motor 45 was issued. The other points are the same as in the first embodiment. Accordingly, the same reference numerals as those in the first embodiment are assigned and the redundant description is omitted, and only different points will be described next.

  As shown in FIG. 9, when the inspection process is started and the warming up or printing process is performed (S401), the rotation speed measurement process of the first drive motor 45 is performed after the process is completed (S402). When the warm-up or printing process is performed after the rotation speed measurement process is performed in S402 (S403), the rotation speed measurement process for the second drive motor 45 is performed after the process is completed (S404). When the second rotation speed is measured, a process for determining an abnormality of the electromagnetic clutch 46 is performed using the two measured rotation speeds (S405).

  When the first rotation speed measurement of S402 is performed, the rotation speed measurement process of the flowchart shown in FIG. 10 is performed. The first rotation speed measurement will be described with reference to the flowchart of FIG.

  When the rotation speed measurement process is started, the same processes from S201 to S204 as in the first embodiment are performed. At this time, a command for switching the electromagnetic clutch 46 to the first mode is issued. Next, in order to measure the rotational speed of the drive motor 45 when a predetermined time T has passed since the rotation stop command for stopping the rotation of the drive motor 45 is issued, the rotation for stopping the rotation of the drive motor 45 in S501. A stop command is issued. When a rotation stop command is issued in S501, measurement of the rotation speed V1 is started (S502). In the measurement of the rotation speed V1, the rotation speed at the time when a predetermined time T has elapsed after the rotation stop command is issued is measured. The rotational speed of the drive motor 45 is detected by the frequency of the FG signal output from the FG sensor. When the predetermined time T has elapsed, it is determined that the measurement of the rotational speed V1 has been completed (S503). Next, a command to switch to the second mode is issued (S504), and the processing of the flowchart of the rotational speed measurement processing in FIG.

  Subsequently, when the second rotation speed measurement of S404 is performed, the rotation speed measurement process of the flowchart shown in FIG. 11 is performed. The second rotation speed measurement process will be described with reference to the flowchart of FIG. The difference from the first rotational speed measurement process is that the mode of the electromagnetic clutch 46 when measuring the rotational speed is not the first mode but the second mode. Therefore, the same reference numerals as those in FIG.

  In FIG. 11, when it is determined in S204 that the target temperature has been reached (S204: Yes), a command to switch the electromagnetic clutch 46 from the first mode to the second mode is issued (S601). In order to measure the rotational speed of the drive motor 45 when a predetermined time T has elapsed since the rotation stop command for stopping the rotation of the drive motor 45 was issued after the command to switch to the second mode was issued, in S602. A rotation stop command for stopping the rotation of the drive motor 45 is issued.

  When a rotation stop command is issued in S602, measurement of the rotation speed V2 is started (S603). In the measurement of the rotation speed V2, the rotation speed at the time when a predetermined time T has elapsed after the rotation stop command is issued is measured. When the predetermined time T has elapsed, it is determined that the measurement of the rotational speed V2 has been completed (S604), and the process of the rotational speed measurement process in FIG. 11 is terminated.

  When the second rotation speed measurement process in S404 in FIG. 9 is completed, an abnormality determination process for the electromagnetic clutch 46 in S405 is performed. The abnormality determination process will be described with reference to the flowchart shown in FIG.

  When the abnormality determination process is started, a speed difference VA between the measured rotational speed V1 and rotational speed V2 is calculated (S605). If the electromagnetic clutch 46 can normally switch between the first mode and the second mode, a speed difference VA as shown in FIG. 13 is calculated. Next, it is determined whether or not the speed difference VA is smaller than a predetermined value VS (S606, an example of a determination unit). The predetermined value VS is set to a time difference between the rotational speed V1 and the rotational speed V2 at which it can be determined that the electromagnetic clutch 46 operates normally. If an abnormality has occurred in the electromagnetic clutch 46, for example, if it becomes impossible to switch from the first mode to the second mode, the rotational speed V2 was measured by switching to the second mode in S601. The clutch 46 is not switched to the second mode, and the rotational speed V2 is measured in the state of the first mode. Therefore, the speed difference VA with respect to the rotational speed V1 is a value substantially close to zero. In S606, it is determined that the speed difference VA is smaller than the predetermined value VS (S606: Yes), and the operation panel indicates that the electromagnetic clutch 46 is abnormal. 40 or the like (S607, an example of a notification unit). When it is determined that the speed difference VA is larger than the predetermined value VS (S606: No), it is determined that the electromagnetic clutch 46 is normal, and the inspection process of this flowchart ends.

[Modification]
In addition, this Embodiment is only a mere illustration and does not limit this invention at all. Therefore, the present invention can be variously improved and modified without departing from the scope of the invention. For example, the image forming apparatus is not limited to a printer, and can be applied to any apparatus having a printing function, such as a copier, a FAX apparatus, and a multifunction peripheral. Further, the printer is not limited to a color printer, and may be a monochrome printer.

  In the first embodiment, in the measurement of the stop time TE1, the time until the rotation of the drive motor 45 stops is measured. However, until the rotation speed of the drive motor 45 reaches a predetermined speed V as shown in FIG. Similarly, in the measurement of the stop time TE2, the time T2 until the rotational speed of the drive motor 45 reaches the predetermined speed V may be measured. By calculating the time difference TA between the time T1 and the time T2 and determining whether the time difference TA is smaller than a predetermined value, it is possible to determine whether the electromagnetic clutch 46 is abnormal. The rotational speed of the drive motor 45 can be detected by the output of the FG sensor. In addition, the rotation speed of the drive motor 45 may be detected using a known rotation speed detector such as an encoder (not shown).

  In the first embodiment, as shown in FIG. 14, after the measurement of the first stop time TE1 is completed in S102, the time difference TEB from the stop time TE2 measured at the time of shipment from the factory and stored in the ROM 32 is used. The electromagnetic clutch 46 may be inspected by determining whether or not the time difference TEB is smaller than the predetermined value TS. When the time difference TEB is smaller than the predetermined value TS, it is considered that the measured stop time TE1 is close to the stop time TE2 stored in the ROM 32, and an abnormality that the electromagnetic clutch 46 cannot be switched from the second mode to the first mode occurs. It can be determined that it is in progress, and the fact is notified. When the time difference TEB is larger than the predetermined value TS, it can be determined that the electromagnetic clutch 46 is normal. Note that the stop time TE2 may be stored in the NVRAM 34 instead of the ROM 32.

  Further, in the first embodiment, as shown in FIG. 14, after the measurement of the first stop time TE1 is completed in S102, the time difference TEC from the stop time TE1 measured at the time of shipment from the factory and stored in the ROM 32. May be calculated, and it may be determined whether or not the time difference TEC is smaller than the predetermined value TS, and the inspection process of the electromagnetic clutch 46 may be performed. When the time difference TEC is larger than the predetermined value TS, it is considered that the measured stop time TE1 is close to the stop time TE2 stored in the ROM 32, and an abnormality that the electromagnetic clutch 46 cannot be switched from the second mode to the first mode occurs. It can be determined that it is, and a notification to that effect is given. When the time difference TEC is smaller than the predetermined value TS, it can be determined that the electromagnetic clutch 46 is normal.

  Further, in the first embodiment, as shown in FIG. 14, the stop time TE2 of S104 is measured at the time of measuring the first stop time TE1 in S102, and the stop time measured at the time of factory shipment and stored in the ROM 32. The time difference TED with TE1 may be calculated, and it may be determined whether or not the time difference TED is smaller than the predetermined value TS, and the electromagnetic clutch 46 may be inspected. When the time difference TED is smaller than the predetermined value TS, it is considered that the measured stop time TE2 is close to the stop time TE1 stored in the ROM 32, and an abnormality that the electromagnetic clutch 46 cannot be switched from the first mode to the second mode occurs. It can be determined that it is in progress, and the fact is notified. When the time difference TED is larger than the predetermined value TS, it can be determined that the electromagnetic clutch 46 is normal.

  Further, in the first embodiment, as shown in FIG. 14, the stop time TE2 of S104 is measured at the time of measuring the first stop time TE1 in S102, the stop time TE2 measured at the time of factory shipment and stored in the ROM 32. The time difference TEE may be calculated to determine whether the time difference TEE is smaller than the predetermined value TS, and the electromagnetic clutch 46 may be inspected. When the time difference TEE is larger than the predetermined value TS, it is considered that the measured stop time TE2 is close to the stop time TE1 stored in the ROM 32, and an abnormality that the electromagnetic clutch 46 cannot be switched from the first mode to the second mode occurs. It can be determined that it is in progress, and the fact is notified. When the time difference TEE is smaller than the predetermined value TS, it can be determined that the electromagnetic clutch 46 is normal.

  In the embodiment, the driving force from the driving motor 45 is transmitted to the rotating members of the developing roller 41, the supply roller 42, and the agitator 43, that is, the driving force from the driving motor 45 is used as the developing roller 41. Although the configuration is shared by the rotation members of the supply roller 42 and the agitator 43, a drive source may be provided for each rotation member. The electromagnetic clutch 46 is also configured to be shared by the rotating members of the developing roller 41, the supply roller 42, and the agitator 43, but a transmission member may be provided for each rotating member.

  Further, in the embodiment, both an abnormality in which the driving force from the drive motor 45 is continuously transmitted and an abnormality in which the driving force is not transmitted are detected. However, both are not necessarily performed, and the driving force is transmitted. It may be only the detection of the continued abnormality. That is, in the case of an abnormality in which the driving force is not transmitted, printing cannot be performed immediately after a failure, so that even if the printer 100 does not execute the inspection process, it is easy for the user to find out that there was an abnormality. Therefore, the control may be simplified by only detecting an abnormality in which the driving force is continuously transmitted. On the other hand, various abnormalities can be detected by detecting abnormalities that are not transmitted.

  In the embodiment, the electromagnetic clutch 46 that switches between the state in which the driving force from the drive motor 45 is transmitted and the state in which the driving force is not transmitted is disposed. However, the transmission member that transmits the driving force is not limited thereto. . For example, a speed change mechanism that changes the rotation speed of the rotating member may be used. In this case, for the speed change mechanism, the state in which the rotating member is rotated at a certain rotational speed is referred to as a first mode, and the state in which the rotating member is rotated at a rotational speed slower than the rotational speed in the first mode is referred to as a second mode. That's fine.

  In the case of the speed change mechanism, the driving force continues to be transmitted to the developing roller 41 even when the mode is switched to the second mode. However, since the rotation speed is slower than that in the first mode, the load resistance of the electromagnetic clutch 46 is larger in the second mode than in the first mode. Therefore, if the electromagnetic clutch 46 is normal, the stop time TE2 is measured to be shorter than the stop time TE1. Therefore, even in the transmission mechanism, as in the embodiment, when measuring the stop time TE2 in which the rotational drive of the drive motor 45 stops after the command to switch to the second mode is issued, the transmission mode is normally switched to the second mode. The time difference between the case of switching and the case of not switching to the second mode is different as in the embodiment.

  Therefore, when the stop time TE2 is measured after a command to switch to the second mode is issued, it is normal if a value close to the stop time TE2 when measured in the second mode is detected at the time of factory shipment. If a value close to the stop time T1 when measured in the first mode at the time of shipment is detected, it can be determined that a failure has occurred in the speed change mechanism and the abnormality continues to transmit the driving force of high-speed rotation.

DESCRIPTION OF SYMBOLS 1 Photoconductor 4 Developing device 8 Fixing device 10 Image forming part 30 Control part 41 Developing roller 42 Supply roller 43 Agitator 45 Drive motor 46 Electromagnetic clutch 50 Process part 81 Fixing roller 82 Pressure roller 83 Heater 84 Temperature sensor 100 Printer

Claims (11)

A drive motor that rotationally drives a rotating member that conveys the developer;
A transmission member for transmitting a driving force for rotating the rotating member to the rotating member;
A first mode in which the transmission member transmits a driving force for rotating the rotating member at a first rotational speed; and a driving force for the transmission member to rotate the rotating member at a second rotational speed that is slower than the first rotational speed. A switching unit for switching between the second mode for transmitting
A control unit for controlling the rotational speed of the drive motor;
A detection unit for detecting the rotation speed of the drive motor after the control unit starts control to reduce the rotation speed of the drive motor to a predetermined speed;
The rotation speed when detected by the detection unit after the command to switch to the first mode is issued, and the rotation speed detected by the detection unit after the command to switch to the second mode is issued. An image forming apparatus comprising: a determination unit that determines whether or not an abnormality has occurred in the transmission member. The image forming apparatus according to claim 1,
A measurement unit that measures the time from when the deceleration control is started until the rotation speed detected by the detection unit reaches the predetermined speed;
The determination unit measures the time when the measurement unit measures after the command to switch to the first mode is issued, and the measurement unit measures after the command to switch to the second mode is issued. An image forming apparatus, wherein when the difference from the time is within a predetermined time, it is determined that an abnormality has occurred in the transmission member. The image forming apparatus according to claim 2,
The determination unit is configured such that a difference between a time when measured by the measurement unit in the state of the first mode and a time measured by the measurement unit after a command to switch to the second mode is issued. Is within a predetermined time, it is determined that an abnormality that cannot be switched from the first mode to the second mode has occurred in the transmission member. The image forming apparatus according to claim 2,
The determination unit includes a time measured by the measurement unit after a command to switch to the first mode is issued, and a time measured by the measurement unit after a command to switch to the second mode is issued. An image forming apparatus that determines that an abnormality has occurred in the transmission member when the difference between the two is within a predetermined time. The image forming apparatus according to claim 1,
A measurement unit that measures the time from when the deceleration control is started until the rotation speed detected by the detection unit reaches the predetermined speed;
The determination unit is configured such that a difference between a time measured by the measurement unit after a command to switch to the first mode is issued and a time measured by the measurement unit in the state of the second mode. Is within a predetermined time, it is determined that an abnormality that cannot be switched from the second mode to the first mode has occurred in the transmission member. The image forming apparatus according to claim 1,
The detection unit detects the rotational speed at a time when a predetermined time has elapsed since the deceleration control was started,
The determination unit detects the rotation speed when detected by the detection unit after a command to switch to the first mode and the detection unit after a command to switch to the second mode are issued. An image forming apparatus comprising: a determination unit that determines that an abnormality has occurred in the transmission member when a difference between the rotation speed and the rotation speed is within a predetermined speed. The image forming apparatus according to claim 1,
The detection unit detects the rotational speed at a time when a predetermined time has elapsed since the deceleration control was started,
The determination unit is configured to detect the rotation speed detected by the detection unit after an instruction to switch to the first mode and the rotation speed detected by the detection unit in the state of the second mode. And a determination unit that determines that an abnormality that cannot be switched from the second mode to the first mode has occurred in the transmission member when the difference is within a predetermined speed. apparatus. The image forming apparatus according to any one of claims 1 to 7,
A fixing unit having a fixing roller for fixing the toner transferred onto the recording paper to the recording paper, and a heating element for heating the fixing roller;
A temperature controller for controlling the temperature of the fixing roller,
The temperature control unit maintains the temperature of the fixing roller at a predetermined temperature when the time is measured by the measurement unit. The image forming apparatus according to any one of claims 1 to 8,
An image forming apparatus comprising: a notification unit configured to notify a user of information relating to an abnormality when the determination unit determines that the abnormality has occurred. The image forming apparatus according to any one of claims 1 to 9,
In the image forming apparatus, the switching unit is in a state in which no driving force is transmitted to the rotating member in the second mode, and stops the rotation of the rotating member. The image forming apparatus according to any one of claims 1 to 10,
The image forming apparatus, wherein the predetermined speed is a speed at which a rotation speed of the drive motor stops.

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