JP2013092615A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of detecting trouble in a transmission member for transmitting driving force to a rotary member of a developing unit.SOLUTION: A printer 100 has a first mode where a transmission member transmits driving force for rotating a rotary member of a developing unit at a first rotational speed and a second mode where the transmission member transmits the driving force for rotating the rotary member at a second rotational speed (<the first rotational speed), and switches the modes as necessary. The printer 100 acquires an amount of developer of an image for an inspection formed after an instruction for switching to the second mode is given, and determines whether or not trouble has occurred in the transmission member, on the basis of the amount of the developer.

Description

  The present invention relates to an image forming apparatus in which a developing device forms a developer image. More specifically, the present invention relates to an image forming apparatus that transmits a driving force output from a driving source to a rotating member of a developing device via a transmission member.

  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 in which the driving force is transmitted to the rotating member and a state in which 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 such as cleaning of the photosensitive member is unnecessary, the clutch is controlled so that the driving force is not transmitted to the rotating member of the developing device, thereby preventing early deterioration of the developer. 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 fails in a state where the driving force is transmitted to the rotating member, the clutch state is not switched and the driving force is transmitted to the rotating member even after issuing a command to switch the driving force to the rotating member. Will continue to do. In this case, it is difficult to detect an abnormality because an image can be formed although it is a failure. If the driving force continues to be transmitted to the rotating member, the stress on the developer becomes excessive, and there is a possibility that the developer may be prematurely deteriorated.

  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 that can detect a failure of a transmission member that transmits a driving force to a rotating member of a developing device.

  An image forming apparatus designed to solve this problem includes an image carrier, a developing device that contains a developer and includes a rotating member that conveys the developer, and forms a developer image on the image carrier; A transmission member that transmits a driving force for rotating the rotating member to the rotating member; a first mode in which the transmitting member transmits a driving force for rotating the rotating member at a first rotation speed; , A switching unit that switches between a second mode for transmitting a driving force that rotates the rotating member at a second rotational speed that is slower than the first rotational speed, and an inspection image using a developer contained in the developing device. And whether or not an abnormality has occurred in the transmission member based on the amount of developer in the inspection image formed in the forming portion after a command to switch to the second mode is issued And a judgment unit for judging It is characterized in that.

  In the image forming apparatus of the present invention, the transmission member transmits a driving force for rotating the rotating member at the first rotation speed, and the transmission member rotates the rotating member at the second rotation speed (<first rotation speed). And a second mode for transmitting the driving force to be transmitted. The rotating member that conveys the developer is provided in the developing device, and includes, for example, a developing roller, a developer supply roller, and a stirring member. Further, examples of the transmission member that can change the rotation speed of the rotation member include a transmission mechanism and a clutch. Further, the second mode includes a state where the rotation member is in a rotation stopped state, that is, a state where the second rotation speed is zero. The image forming apparatus according to the present invention acquires the developer amount of the inspection image formed after the command to switch to the second mode is issued as a failure inspection of the transmission member, and transmits based on the developer amount. It is determined whether or not an abnormality has occurred in the member.

  That is, when the inspection image is formed in the second mode, the second mode is slower than the first mode, and therefore, if the transmission member is normal, an inspection image having a lower density than the first mode is formed. The 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 the process is continued, an inspection image having the same density as that formed in the first mode is formed. Therefore, in the image forming apparatus of the present invention, the inspection image is formed after the command to switch to the second mode is issued, and the developer amount of the formed inspection image is obtained, so that the developer amount is obtained. Based on this, it can be determined whether or not the transmission member has an abnormality that continues to operate in the first mode.

  Specifically, the determination unit determines the developer amount of the inspection image when formed by the forming unit in the state of the first mode and the formation after an instruction to switch to the second mode is issued. When the difference between the developer amount of the inspection image formed at the portion is within a predetermined amount, it may be determined that an abnormality has occurred in the transmission member. That is, if the developer amount of the inspection image formed after the command to switch to the second mode is within the range equivalent to the developer amount of the inspection image when formed in the first mode state Therefore, 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 addition, the image forming apparatus of the present invention determines whether or not an abnormality has occurred based on the developer amount of the inspection image formed in the forming unit after the command to switch to the first mode is issued. It is good to provide the 2nd judgment part to judge. According to this configuration, contrary to the case of detecting an abnormality that continues to operate in the first mode described above, an inspection image is formed after a command to switch to the first mode is issued, and the developer amount is set to the amount of developer. Based on this, it is determined whether an abnormality has occurred. By combining this inspection with the above-described inspection for detecting an abnormality in which the transmission member continues to operate in the first mode, more various abnormalities can be detected.

  Specifically, the second determination unit is configured to output a developer amount of the inspection image when the forming unit is formed in the state of the second mode and a command to switch to the first mode. It may be determined that an abnormality has occurred when the difference between the developer amount of the inspection image formed in the forming portion is within a predetermined amount. That is, if the developer amount of the inspection image formed after the instruction to switch to the first mode is within the range equivalent to the developer amount of the inspection image formed in the second mode state Therefore, it can be determined that the first mode is not established and the transmission member continues to operate in the second mode.

  The image forming apparatus of the present invention continues counting at the first interval in the first mode, and at a second interval that is wider than the first interval in the second mode. A counting unit that continues counting, and a management unit that manages whether printing is possible based on the count value of the counting unit, and the counting unit is configured to detect the first when the determining unit determines that an abnormality has occurred. It is better to continue counting at intervals of. In the first mode state, the rotation speed of the rotating member is high, and the stress applied to the developer is greater than that in the second mode state. Therefore, the developer tends to deteriorate faster than in the second mode state. Therefore, when an abnormality that continues to operate in the first mode occurs, more accurate management can be performed by maintaining the count interval in the first mode.

  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 or a decrease in the number of printable sheets. The notification method corresponds to, 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.

  The determination unit may acquire the developer amount of the inspection image using a density sensor. By acquiring the developer amount using an existing density sensor, the number of parts can be prevented from increasing.

  The forming unit may form the inspection image during a correction operation involving printing. Since the correction operation with printing is performed by pressing the developing device against the image carrier, it is not necessary to press the developing device only for the inspection of the transmission member. Therefore, an increase in stress on the developing device or the image carrier is suppressed.

  The forming unit may form a solid image having a width in the sub-scanning direction wider than a width of the developing region in the rotation direction of the image carrier before forming the inspection image. By forming the solid image before forming the inspection image, the developer already supplied to the developing roller can be discharged. Therefore, more accurate judgment can be expected.

  In addition, the image forming apparatus of the present invention may include a printing unit that prints the inspection image formed by the forming unit on a sheet. By printing the inspection image on the paper as in this configuration, the service person can visually check whether there is an abnormality and the convenience is improved.

  Further, the switching unit may stop the rotation of the rotating member in the second mode in a state where no driving force is transmitted to the rotating member. When the rotation of the rotating member is stopped, the second rotation speed is 0, and no image is formed on the image carrier. Therefore, the developer amount of the inspection image formed in the second mode is 0 or an approximate value of 0.

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

2 is a block diagram illustrating an electrical configuration of the MFP. FIG. FIG. 2 is a diagram illustrating a schematic configuration of an image forming unit of the MFP illustrated in FIG. 1. FIG. 3 is a diagram illustrating a schematic configuration of a process unit of the MFP illustrated in FIG. 2. It is a figure which shows the example of arrangement | positioning of a density sensor, and the image for a test | inspection. It is a flowchart which shows the procedure of the test | inspection process concerning embodiment. It is a figure which shows the printing state of the image for a test | inspection at the time of test | inspecting in 2nd mode. It is a figure which shows the example of the measured value of a density | concentration sensor at the time of test | inspecting in 2nd mode. It is a figure which shows the printing state of the image for a test | inspection at the time of test | inspecting in 1st mode. It is a figure which shows the example of the measured value of a density | concentration sensor at the time of test | inspecting in 1st mode. It is a figure which shows the example of the output image to a paper at the time of transfering to an output determination function.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a printing apparatus according to the invention will be described 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.

[Printer configuration]
As shown in FIG. 1, 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. , Second determination unit, count unit, and management unit). The control unit 30 also includes an image forming unit 10 (an example of a forming unit and a printing unit) that forms an image on a sheet, and an operation panel 40 (an example of a notification unit) that displays an operation status and receives an input operation by a user. Are electrically connected.

  The CPU 31 performs a calculation for realizing various functions such as a printing function and an inspection function to be described later, and becomes 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 NVRAM 34 in accordance with a control program read from the ROM 32 and 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.

[Configuration of printer image forming unit]
Next, 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 onto 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 the process units 50C, 50M, 50Y, and 50K with light, and a conveyance belt 7 that conveys a sheet to the transfer position of each of the process units 50C, 50M, 50Y, and 50K. , And a density sensor 61 for measuring the density of the image formed on the conveyor belt 7.

  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 transport path 11 (a chain line in FIG. 2) is provided so as to be guided to the upper discharge tray 92.

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

  FIG. 3 shows a schematic configuration of the process unit 50K. The process unit 50K includes a drum-shaped photoreceptor 1 (an example of an image carrier), a charging device 2 that uniformly charges the surface of the photoreceptor 1, and a developing device that develops an electrostatic latent image with toner. 4 and a transfer device 5 for transferring the toner image on the photoreceptor 1 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 aji data 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 as well as a toner conveying function.

  Further, 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 a driving force by excitation. The drive motor 45 and the electromagnetic clutch 46 are controlled by the control unit 30.

  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. Thereafter, exposure is performed with light from the exposure device 53 to form an electrostatic latent image. Next, toner is supplied to the photoreceptor 1 via the developing device 4. Thereby, 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 a sheet. Thereafter, the sheet on which the toner image is transferred is conveyed to the fixing device 8 and the toner image is thermally fixed on the sheet. Then, the sheet after fixing is discharged to a paper 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.

  Further, the density sensor 61 is positioned downstream of the process units 50C, 50M, 50Y, and 50K and upstream of the fixing device 8 in the paper transport direction. The density sensor 61 measures the density of an image transferred from the process units 50C, 50M, 50Y, and 50K onto the conveyance belt 7.

  Specifically, as shown in FIG. 4, the density sensor 61 includes two sensors, a sensor 61R disposed on the right side in the width direction of the conveyor belt 7 and a sensor 61L disposed on the left side. Each of the sensors 61R and 61L is a reflective optical sensor in which a light emitting element 62 (for example, an LED) and a light receiving element 63 (for example, a phototransistor) are paired. The density sensor 61 is configured such that the light emitting element 62 emits light from the oblique direction to the surface of the conveyor belt 7 (dotted line frame E in FIG. 4), and the light receiving element 63 receives the light.

  The printer 100 forms an inspection image 66 by each of the process units 50C, 50M, 50Y, and 50K, and transfers the inspection image 66 onto the conveyance belt 7. In this embodiment, the inspection image formed by the process unit 50C is 66C, the inspection image formed by the process unit 50M is 66M, the inspection image formed by the process unit 50Y is 66Y, and the process unit 50K is formed. The inspection image is 66K. Then, the conveying belt 7 is conveyed in the direction of arrow A in FIG.

  The density sensor 61 detects the amount of light received when the inspection image 66 passes through the dotted frame E in FIG. At this time, as the amount of toner increases, the light from the light emitting element 62 diffuses, and the amount of light received by the light receiving element 63 decreases. Therefore, the toner amount of the inspection image 66 can be calculated according to the magnitude of the received light amount. Note that the inspection image 66 shown in FIG. 4 is for convenience of explanation, and is different from the inspection image when actually performing density correction and the inspection image when performing inspection of the electromagnetic clutch 46 described later. .

  In addition, a waste toner box 78 for collecting toner adhering to the conveyor belt 7 is disposed in contact with the conveyor belt 7. The waste toner box 78 collects toner constituting the inspection image 66.

[Electromagnetic clutch inspection process]
Next, an inspection process (an example of a switching unit, a forming unit, a determination unit, and a second 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 before or after the execution of the correction process when conditions for executing a correction process involving printing such as positional deviation correction and density correction are satisfied. Note that the execution conditions of the correction process include, for example, the number of printed sheets, the energization time, the temperature condition, and vibration detection since the previous correction process was performed.

  In the inspection process, first, as a preparatory operation, starting of the drive motor 45, application of a bias necessary for transferring the inspection image to the conveyance belt 7, pressure contact of the developing roller 41 to the photosensitive member 1, and the like are performed (S101). . Note that control is omitted for items that have already been implemented.

  After completion of the preparatory operation, a command to switch to the second mode is issued, and the electromagnetic clutch 46 is switched to the second mode (S102, an example of a switching unit). That is, the electromagnetic clutch 46 is controlled so that the driving force from the driving motor 45 is not transmitted to each rotating member of the developing device 4.

  Next, a solid image is formed (S103). In step S103, the toner already supplied to the developing area (the nip area between the developing roller 41 and the photosensitive member 1) before the start of the inspection process, or the toner accumulated on the upstream side in the rotation direction of the photosensitive member 1 from the developing area. This is done to vomit. The size of the solid image formed in S103 (hereinafter referred to as “pre-inspection solid image”) may be such that the width in the sub-scanning direction is at least wider than the width of the photosensitive region 1 in the development region. The solid image before inspection is transferred from the photoreceptor 1 to the conveyance belt 7.

  Next, the inspection image 66 is formed (S104, an example of a forming unit). The inspection image 66 of this embodiment is a solid image equivalent to the solid image before inspection. The inspection image 66 is transferred from the photoreceptor 1 to the conveyor belt 7 following the pre-inspection solid image. After S103 and S104, the pre-inspection solid image and the inspection image 66 transferred to the transport belt 7 are read by the density sensor 61 (S105).

  Note that S104 is after a command to switch to the second mode is issued. Therefore, if the electromagnetic clutch 46 is normal, the toner is not transferred from the developing device 4 to the photoreceptor 1. That is, in S104, if the electromagnetic clutch 46 is normal, control for forming the inspection image 66 is performed, but no image is actually formed.

  Next, it is determined whether or not there is an abnormality in the electromagnetic clutch 46 based on the measured value of the density sensor 61 read in S105, that is, the toner amount on the conveyor belt 7 obtained from the amount of received light (S106, determination unit). One case).

  Specifically, if the electromagnetic clutch 46 is normal, as shown in FIG. 6 (A), in the area 661 where the solid image before inspection is formed, not a little toner is supplied to the developing area before the inspection starts. However, toner is not detected in the region 662 where the inspection image 66 is formed. On the other hand, if a failure occurs while the driving force is continuously transmitted to the electromagnetic clutch 46, the driving force continues to be transmitted to each rotating member of the developing device 4 even after a command to switch to the second mode is issued. . This state is the same as the first mode, and an image is formed. Therefore, as shown in FIG. 6B, a solid image is formed in both the region 661 where the pre-inspection solid image is formed and the region 662 where the inspection image 66 is formed, and these images are formed in the first mode. The same amount of toner is detected.

  FIG. 7 is a diagram showing the amount of light received by the density sensor 61 in time series. The amount of light received by the density sensor 61 is large in a region where no toner is present on the transport belt 7 and decreases as the toner amount increases. FIG. 7A shows a case where the electromagnetic clutch 46 is normal (see FIG. 6A). Since no image is formed in the region 662 where the inspection image 66 is formed, the density sensor 61 is shown. As a measured value, a value almost equal to that detected when the conveying belt 7 is detected is detected. On the other hand, FIG. 7B shows a case where the electromagnetic clutch 46 fails in a state where the driving force continues to be transmitted (see FIG. 6B). In the region 662 where the inspection image 66 is formed, a solid image is obtained. Therefore, a value substantially equal to that when the inspection image 66 is formed with the electromagnetic clutch 46 in the first mode is detected as the measured value of the density sensor 61.

  As described above, the amount of toner in the region 662 where the inspection image 66 is formed differs between when the electromagnetic clutch 46 is normal and when a failure occurs while the driving force is continuously transmitted. From this, it can be determined whether or not there is an abnormality in the electromagnetic clutch 46 based on the amount of light received by the density sensor 61 in the region 662. Therefore, the printer 100 stores the received light amount detected when the inspection image 66 is formed in the first mode in advance as the first reference received light amount. In S106, the first reference received light amount, If the difference from the received light amount read in S105 is within a predetermined amount, it is determined that a failure has occurred while the driving force continues to be transmitted.

  If it is determined that there is an abnormality in the electromagnetic clutch 46 (S106: YES), the user is notified that a failure has occurred in the electromagnetic clutch 46 in a state where the driving force continues to be transmitted (S107, an example of a notification unit). Examples of the notification means include lighting of an error lamp, display of an error message on the operation panel 40, voice guidance, and mail transmission.

  Next, the count control in the management process is changed (S108). In other words, the printer 100 counts the number of rotations of the drive motor 45 for each developing device 4, and determines that the toner has reached the end of its life when the count value is equal to or greater than the threshold value, and makes the printing impossible. Is running. In this management process, the count is stopped after the command to switch to the second mode is issued to the electromagnetic clutch 46, that is, after changing to a state where the driving force is not transmitted to the rotating member of the developing device 4 (counting unit). , An example of the management unit). By switching the counting method according to the rotation state of the rotating member in this manner, it is possible to prevent the end of the life of the toner from being determined earlier than it actually is.

  On the other hand, in the above-described management process, if the electromagnetic clutch 46 fails in a state where the driving force continues to be transmitted, if the count is stopped after the command for switching the electromagnetic clutch 46 to the second mode is issued, the printing is permitted. Thus, the stress on the toner continues while the count value for determining is stopped. Therefore, the toner reaches the end of its life earlier than planned. In particular, since the printing itself is possible even if the electromagnetic clutch 46 breaks down while the driving force continues to be transmitted, the user may continue to use the printer 100. As described above, when printing is continued even when the toner has reached the end of its life, so-called toner fog often occurs, which may deteriorate the image quality.

  Therefore, in S108, the count control is changed so as to continue counting even after a command to switch to the second mode is issued (an example of a counting unit). Thereby, more accurate management is performed.

  After S108 or when it is determined that there is no abnormality in the electromagnetic clutch 46 (S106: NO), a command to switch to the first mode is issued, and the electromagnetic clutch 46 is switched to the first mode. (S122, an example of a switching unit). 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, a solid image is formed (S123). S123 is performed for discharging the toner as in S103. The pre-inspection solid image formed in S123 may be equivalent to the pre-inspection solid image formed in S103.

  Next, the inspection image 66 is formed (S124, an example of a forming unit). In this embodiment, the inspection image 66 formed in S124 is a solid image equivalent to the solid image before inspection in S123. After S123 and S124, the pre-inspection solid image and the inspection image 66 transferred to the transport belt 7 are read by the density sensor 61 (S125).

  Note that S124 is after a command to switch to the first mode is issued. Therefore, if the electromagnetic clutch 46 is normal, the toner is transferred from the developing device 4 to the photoreceptor 1. That is, if the electromagnetic clutch 46 is normal, an image is actually formed and transferred onto the conveyor belt 7.

  Next, based on the measured value of the density sensor 61 read in S125, that is, the toner amount on the conveyor belt 7 obtained from the received light amount, it is determined whether or not there is an abnormality in the electromagnetic clutch 46 (S126, second determination). Part).

  Specifically, if the electromagnetic clutch 46 is normal, as shown in FIG. 8A, a solid image is formed in both the region 663 where the pre-inspection solid image is formed and the region 664 where the inspection image 66 is formed. Therefore, a predetermined amount or more of toner is detected. On the other hand, when a failure occurs in a state where the driving force is not transmitted to the electromagnetic clutch 46, the driving force is not transmitted to the rotating members of the developing device 4 even after a command for switching to the first mode is issued. This state is the same as the second mode, and no image is formed. For this reason, as shown in FIG. 8B, in the region 663 where the pre-inspection solid image is formed, the toner supplied to the development region before the start of the inspection is detected to some extent, but the region where the inspection image 66 is formed. At 664, no toner is detected.

  FIG. 9 is a diagram showing the amount of light received by the density sensor 61 in time series. FIG. 9A shows a case where the electromagnetic clutch 46 is normal (see FIG. 8A), and a solid image is formed in the region 664 where the inspection image 66 is formed. As the measurement value 61, a received light amount equal to or less than a predetermined value is detected. On the other hand, FIG. 9B shows a case where the electromagnetic clutch 46 fails in a state where the driving force is not transmitted (see FIG. 8B). In the region 664 where the inspection image 66 is formed, the image is not displayed. Since it is not formed, a light reception amount that is equal to or greater than a predetermined value as a measurement value of the density sensor 61 and a value that is substantially the same as when a region where no toner is present on the conveyance belt 7 is detected is detected.

  As described above, the amount of toner in the region 664 in which the inspection image 66 is formed differs between when the electromagnetic clutch 46 is normal and when a failure occurs while the driving force is not transmitted. From this, based on the amount of light received by the density sensor 61 in the region 664, it can be determined whether or not there is an abnormality in the printer 100. Therefore, the printer 100 stores the received light amount detected when the inspection image 66 is formed in the second mode in advance as the second reference received light amount. In S126, the second reference received light amount, When the difference from the received light amount read in S125 is within a predetermined amount, it can be determined that a failure has occurred in a state where the driving force is not transmitted. Note that the predetermined amount used in S126 may be the same as or different from the predetermined amount used in S106.

  If it is determined that there is an abnormality in the electromagnetic clutch 46 (S126: YES), the user is notified that a failure has occurred in the printer 100 (S127, an example of a notification unit). In this embodiment, it is determined that the electromagnetic clutch 46 is abnormal when the inspection image is not formed after the command to switch to the first mode is issued. However, the malfunction of other devices (for example, failure of the photosensitive member 1 or Since an image is not formed even in the case of a scratch on the conveyor belt 7, it is difficult to accurately distinguish from these abnormalities. For this reason, if the electromagnetic clutch 46 is informed that it has failed, it will be falsely reported if another device has failed. Therefore, in S127, it is preferable to keep the error message not limited to the failure of the electromagnetic clutch 46 or the error message that the electromagnetic clutch 46 may be broken.

  After S127 or when it is determined that there is no abnormality in the electromagnetic clutch 46 (S126: NO), post-processing is performed as necessary (S129). Post-processing includes, for example, stopping the drive motor 45, stopping application of bias, and separating the developing roller 41 from the photosensitive member 1. After S129, the inspection process is terminated.

  In the inspection process of this embodiment, the inspection (S102 to S108) when the electromagnetic clutch 46 is switched to the second mode is first performed, and the inspection (S122) when the electromagnetic clutch 46 is switched to the first mode. ˜S127) is performed later, but may be performed in reverse order.

  In the inspection processing of this embodiment, the density sensor 61 reads the inspection image 66 transferred onto the conveyor belt 7 to determine whether the electromagnetic clutch 46 is abnormal or not by the printer 100 itself. A printing mode (an example of a printing unit) may be provided in which 66 is printed on a sheet and the user determines whether the electromagnetic clutch 46 is abnormal. The transition to the print mode is performed by an operation from the operation panel 40, for example.

  When the mode is shifted to the print mode, for example, as the inspection image 66, a message image for informing whether the image is normal or abnormal is formed as shown in FIG. FIG. 10 shows a case where (A) is normal, (B) shows an abnormality in which the driving force is continuously transmitted, and (C) shows a case where an abnormality in which the driving force is not transmitted occurs. ing. Further, the inspection image 665 is an inspection image formed after a command to switch to the first mode is issued, and an image is formed if the electromagnetic clutch 46 is normal, and thus is a message image for notifying normality. . On the other hand, the inspection image 667 is an inspection image formed after a command to switch to the second mode is issued, and an image is not formed if the electromagnetic clutch 46 is normal, and thus is a message image for notifying abnormality. The solid image preceding the inspection images 665 and 667 is a pre-inspection solid image.

  Control for forming such inspection images 665 and 667 is performed, and printing is performed on the paper 90, respectively. Thus, when the electromagnetic clutch 46 is normal, as shown in FIG. 10A, the inspection image 665 formed after the command to switch to the first mode is printed and the command to switch to the second mode is printed. The inspection image 667 formed after the is issued is not printed.

  On the other hand, when an abnormality in which the driving force continues to be transmitted has occurred, as shown in FIG. 10B, the inspection images 665 and 667 are printed together. In addition, when an abnormality in which the driving force is not transmitted has occurred, the inspection images 665 and 667 are not printed as shown in FIG. Therefore, the user can grasp the abnormality of the printer 100 by looking at the output paper 90.

  As described above in detail, in the printer 100 according to the present embodiment, when the inspection image is formed in the second mode, the driving force is not transmitted to each rotating member of the developing device 4, and therefore the inspection is performed if the electromagnetic clutch 46 is normal. The work image 66 is not formed. On the other hand, if an abnormality occurs in the electromagnetic clutch 46 in the first mode, that is, if the transmission of the driving force to each rotating member of the developing device 4 is not interrupted, a command to switch to the second mode is issued. Even after this, an inspection image having the same toner amount as that formed in the first mode is formed. Therefore, the printer 100 forms the inspection image 66 after the command to switch to the second mode is issued, and acquires the received light amount (equivalent to the toner amount) of the formed inspection image 66, thereby receiving the received light. Based on the amount, it can be determined whether or not the electromagnetic clutch 46 has an abnormality that continues to operate in the first mode.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the image forming apparatus is not limited to a printer, but can be applied to any apparatus having a printing function, such as a copier, a FAX apparatus, or a multifunction machine. Further, the printer is not limited to a color printer, and may be a monochrome printer.

  In the embodiment, the toner amount of the inspection image 66 is calculated based on the measurement value of the density sensor. However, a dedicated sensor for detecting the toner amount of the inspection image 66 may be provided. It should be noted that an increase in the number of parts can be prevented by using a sensor that already exists for other purposes such as positional deviation correction and density correction.

  In the embodiment, the toner amount of the inspection image 66 passing on the conveyance belt 7 is acquired. However, the toner amount of the inspection image 66 passing on the photoreceptor 1 may be acquired. In this case, a sensor is arranged at a place where the inspection image 66 passing on the photosensitive member 1 can be detected.

  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. The rotation members of the supply roller 42 and the agitator 43 are shared. However, a drive source may be provided for each of the rotation members. Also, the electromagnetic clutch 46 is 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 individually provided for each rotating member.

  In the embodiment, the timing of executing the inspection process is before or after the execution of the correction process with printing, but is not limited thereto. For example, it may be executed when the printer 100 is activated. It may also be executed when an execution instruction is input from the user. In the correction operation with printing, it is necessary to form an inspection image for the correction operation, and it is necessary to press the developing roller 41 against the photoreceptor 1. Therefore, when performing the inspection process, the operation of pressing the developing roller 1 can be used as the correction operation. Therefore, an increase in stress on the developing roller 41 or the photoreceptor 1 is suppressed.

  In the embodiment, both an abnormality in which the driving force from the driving 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 it is easy for the user to find out that there is an abnormality even if the printer 100 does not execute the inspection process. Therefore, the control may be simplified by only detecting an abnormality in which the driving force is continuously transmitted. On the other hand, a variety of abnormalities can be detected by detecting abnormalities that are not transmitted as in the embodiment.

  In the embodiment, the abnormality of the electromagnetic clutch 46 is determined based on the difference between the toner amount stored in the first mode stored in advance and the toner amount after the command to switch to the second mode is issued. However, the judgment method is not limited to this. For example, as in the embodiment, the toner amount of the inspection image 66 after the instruction to switch to the second mode is issued, and the toner amount of the inspection image 66 after the instruction to switch to the first mode is issued. When both are measured, the difference between the former toner amount and the latter toner amount may be obtained, and if the difference is within a predetermined amount, it may be determined that a failure has occurred. That is, if both toner amounts are within the same range, there is a high possibility that switching to either mode has failed. Therefore, it can be determined that the electromagnetic clutch 46 is abnormal.

  In the above case, specifically, if the measured toner amount is close to the reference value of the toner amount when formed in the first mode, it can be determined that a failure has occurred while the driving force continues to be transmitted. If the toner amount is close to the reference value when formed in the second mode, it can be determined that a failure has occurred without the driving force being 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, an image having a low density, that is, an image having a small amount of toner is formed as compared with an image formed in the first mode. Therefore, even in the case of the speed change mechanism, when the inspection image 66 is formed after the command to switch to the second mode is issued as in the embodiment, the second mode is changed to the second mode. The amount of toner detected by the density sensor 61 differs from that in the case where the mode is not switched as in FIG.

  Therefore, when the inspection image 66 is formed after the command to switch to the second mode is issued, it is normal if a value close to the reference value (low density) of the toner amount when formed in the second mode is detected. If a value close to the reference value (high density) of the toner amount when formed in the first mode is detected, a malfunction has occurred in the transmission mechanism, and an abnormality that continues to transmit the driving force of high-speed rotation has occurred. It can be judged that there is.

DESCRIPTION OF SYMBOLS 1 Photosensitive body 4 Developing apparatus 7 Conveyor belt 10 Image forming part 30 Control part 41 Developing roller 45 Drive motor 46 Electromagnetic clutch 50 Process part 61 Density sensor 66 Inspection image 100 Printer

Claims (12)

An image carrier;
A developing device that contains a developer and includes a rotating member that conveys the developer, and forms a developer image on the image carrier;
A transmission member for transmitting a driving force for rotating the rotating member to the rotating member;
The transmission member transmits a driving force for rotating the rotating member at a first rotation speed, and the transmission member rotates the rotating member at a second rotation speed that is slower than the first rotation speed. A switching unit for switching between the second mode for transmitting the driving force;
A forming unit that forms an image for inspection using a developer contained in the developing device;
A determination unit that determines whether or not an abnormality has occurred in the transmission member based on a developer amount of the inspection image formed in the forming unit after a command to switch to the second mode is issued;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
The determination unit is formed in the forming unit after the developer amount of the inspection image when formed in the forming unit in the state of the first mode and a command to switch to the second mode are issued. An image forming apparatus comprising: determining that an abnormality has occurred in the transmission member when a difference between a developer amount of the inspection image and the inspection image is within a predetermined amount. The image forming apparatus according to claim 1, wherein:
A second determination unit configured to determine whether or not an abnormality has occurred based on a developer amount of the inspection image formed in the forming unit after a command to switch to the first mode is issued; An image forming apparatus comprising the image forming apparatus. The image forming apparatus according to claim 3,
The second determination unit sends the developer amount of the inspection image when formed in the forming unit in the state of the second mode and an instruction to switch to the first mode to the forming unit. An image forming apparatus that determines that an abnormality has occurred when a difference between the developer amount of the inspection image formed in the above is within a predetermined amount. In the image forming apparatus according to any one of claims 1 to 4,
A counting unit that continues counting at a first interval in the state of the first mode, and continues counting at a second interval that is wider than the first interval in the state of the second mode;
A management unit that manages whether printing is possible based on the count value of the counting unit;
With
The image forming apparatus according to claim 1, wherein the counting unit continues counting at the first interval when the determination unit determines that an abnormality has occurred. The image forming apparatus according to any one of claims 1 to 5,
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 6,
The determination unit acquires an amount of developer of the inspection image using a density sensor. In the image forming apparatus according to any one of claims 1 to 7,
The image forming apparatus, wherein the forming unit forms the inspection image during a correction operation involving printing. In the image forming apparatus according to any one of claims 1 to 8,
The image forming apparatus, wherein the forming unit forms a solid image having a width in a sub-scanning direction wider than a width in a rotation direction of the image carrier in a developing region before forming the inspection image. The image forming apparatus according to any one of claims 1 to 9,
An image forming apparatus comprising: a printing unit configured to print the inspection image formed by the forming unit on a sheet. In the image forming apparatus according to any one of claims 1 to 10,
The image forming apparatus according to claim 1, wherein in the second mode, the switching unit is in a state where a driving force is not transmitted to the rotating member and stops the rotation of the rotating member. The image forming apparatus according to claim 1,
The determination unit includes the developer amount of the inspection image formed in the forming unit after a command to switch to the first mode and the forming unit after a command to switch to the second mode are issued. An image forming apparatus comprising: determining that an abnormality has occurred in the transmission member when a difference between a developer amount of the inspection image formed in step 1 is within a predetermined amount.