Image forming apparatus and method for controlling image forming apparatus

Abstract

An image forming device and a control method for an image forming device are provided to detect abnormality in the replenishment of colorant in a colorant cartridge. The image forming device according to one embodiment comprises: a photosensitive drum, an exposure device, a developer, a toner concentration sensor, a toner supply motor, and a processor. The exposure device exposes the photosensitive drum based on image data. The developer forms a toner image on the photosensitive drum using toner supplied from the toner cartridge. The toner concentration sensor detects the toner concentration in the developer. The toner supply motor supplies toner from the toner cartridge to the developer based on the toner concentration. The processor detects abnormality in the replenishment of the colorant container based on a toner supply rate calculated based on a pixel total value as a cumulative value of pixel values of the image data and a toner supply motor total value as a cumulative value of the driving time of the toner supply motor, and a printing rate of the image data.

Description

Technical Field

[0001] Embodiments of the present invention generally relate to an image forming apparatus and a method for controlling the image forming apparatus. Background Art

[0002] The image forming apparatus receives toner from a toner cartridge and performs an image forming process to form a toner image on a photosensitive drum. The image forming apparatus then transfers the toner image on the photosensitive drum to a print medium.

[0003] The image forming apparatus estimates the remaining toner amount in the toner cartridge based on the drive amount (toner supply motor total value) of a motor (toner supply motor) for driving a spiral member (delivery mechanism) that delivers toner from the toner cartridge to the image forming apparatus. When the toner supply motor total value exceeds a near-end threshold, the image forming apparatus detects a near-end toner condition, indicating that little toner remains in the toner cartridge.

[0004] The image forming apparatus also includes a toner concentration sensor that detects the toner concentration in a developing unit that receives toner from a toner cartridge. Upon detecting a decrease in toner concentration, the image forming apparatus replenishes toner via a toner replenishing motor. If the toner concentration cannot be restored despite operation of the toner replenishing motor, the image forming apparatus detects toner exhaustion, indicating that the toner cartridge is empty.

[0005] For example, a toner cartridge's delivery mechanism or toner container refill failure may occur. These failures can occur when the sealant blocking the toner cartridge's refill port becomes stuck, or when the toner inside the cartridge reaches a high temperature during storage, causing the toner to solidify. In the event of such a toner container refill failure, even activating the toner refill motor will prevent the toner concentration from being restored. However, there's a problem: the user may not be aware of the toner container refill failure until the toner is depleted. Summary of the Invention

[0006] An object of the present invention is to provide an image forming apparatus and a method for controlling the image forming apparatus, which detect an abnormality in the replenishment of toner in a toner cartridge.

[0007] An image forming apparatus according to one embodiment includes a photosensitive drum, an exposure device, a developer, a toner concentration sensor, a toner supply motor, and a processor. The exposure device exposes the photosensitive drum based on image data. The developer forms a toner image on the photosensitive drum using toner supplied from a toner cartridge. The toner concentration sensor detects the toner concentration in the developer. The toner supply motor supplies toner from the toner cartridge to the developer based on the toner concentration. The processor detects a toner container supply abnormality based on a toner supply rate and a printing rate of the image data, the toner supply rate being calculated based on a pixel total value, which is a cumulative value of pixel values of the image data, and a toner supply motor total value, which is a cumulative value of the driving time of the toner supply motor.

[0008] A control method for an image forming device according to one embodiment, wherein the image forming device comprises: a photosensitive drum; an exposing device for exposing the photosensitive drum based on image data; a developing device for forming a colorant image on the photosensitive drum using colorant supplied from a colorant cartridge; a colorant concentration sensor for detecting the colorant concentration in the developing device; a toner supply motor for supplying toner from the colorant cartridge to the developing device based on the toner concentration; and a processor for detecting a colorant container supply abnormality based on a toner supply rate and a printing rate of the image data, wherein the toner supply rate is calculated based on a pixel total value which is an accumulated value of pixel values of the image data and a toner supply motor total value which is an accumulated value of a driving time of the toner supply motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a diagram for explaining a configuration example of an image forming apparatus according to an embodiment.

[0010] Figure 2 This is a diagram for explaining a configuration example of a portion of an image forming unit according to an embodiment.

[0011] Figure 3 These are explanatory diagrams for explaining an example of the operation of the image forming apparatus according to the first embodiment.

[0012] Figure 4 These are explanatory diagrams for explaining an example of the operation of the image forming apparatus according to the first embodiment.

[0013] Figure 5 These are explanatory diagrams for explaining an example of the operation of the image forming apparatus according to the first embodiment.

[0014] Figure 6 These are explanatory diagrams for explaining an example of the operation of the image forming apparatus according to the first embodiment.

[0015] Figure 7 Explanatory diagrams for explaining an example of the operation of the image forming apparatus according to the second embodiment.

[0016] Description of reference numerals:

[0017] 1 Image forming device, 2 Toner cartridge, 11 Housing, 12 Communication interface, 13 System controller, 14 Display unit, 15 Operation interface, 16 Paper tray, 17 Paper discharge tray, 18 Conveyor unit, 19 Image forming unit, 20 Fuser, 21 Processor, 22 Memory, 31 Paper feed path, 32 Paper discharge path, 33 Pickup roller, 41 Loading unit, 42 Processing unit, 43 Exposer, 44 Transfer mechanism, 51 Toner storage container, 52 Toner delivery mechanism, 53 Memory, 61 Toner replenishing motor, 71 Photosensitive drum, 72 Cleaner, 73 Charger, 74 Developer, 81 Developer container, 82 Stirring mechanism, 83 Developing roller, 84 Doctor blade, 85 ATC sensor, 91 Primary transfer belt, 92 Secondary transfer counter roller, 93 Primary transfer roller, 94 Secondary transfer roller, 95 Heat roller, 96 Press roller. DETAILED DESCRIPTION

[0018] Hereinafter, an image forming apparatus and a method for controlling the image forming apparatus according to an embodiment will be described with reference to the drawings.

[0019] Figure 1 It is an explanatory diagram for explaining a configuration example of the image forming apparatus 1 according to one embodiment.

[0020] The image forming apparatus 1 is, for example, a multifunction printer (MFP) that performs various processes such as image formation while conveying a recording medium such as a print medium. The image forming apparatus 1 is, for example, a solid-state scanning printer (e.g., an LED printer) that scans an LED panel that performs various processes such as image formation while conveying a recording medium such as a print medium.

[0021] For example, the image forming apparatus 1 receives toner from a toner cartridge 2 and forms an image on a print medium using the received toner. The toner may be a single color toner or a color toner such as cyan, magenta, yellow, or black.

[0022] like Figure 1 As shown, the image forming apparatus 1 includes a housing 11 , a communication interface 12 , a system controller 13 , a display unit 14 , an operation interface 15 , a plurality of paper trays 16 , a paper discharge tray 17 , a conveying unit 18 , an image forming unit 19 , and a fixing unit 20 .

[0023] The housing 11 is a main body of the image forming apparatus 1 and houses a communication interface 12 , a system controller 13 , a display unit 14 , an operation interface 15 , a plurality of paper trays 16 , a paper discharge tray 17 , a conveying unit 18 , an image forming unit 19 , and a fixing unit 20 .

[0024] The communication interface 12 is an interface for communicating with other devices. For example, the communication interface 12 is used to communicate with a higher-level device (external equipment). For example, the communication interface 12 is configured as a LAN connector. Furthermore, the communication interface 12 wirelessly communicates with other devices using standards such as Bluetooth (registered trademark) or Wi-Fi (registered trademark).

[0025] The system controller 13 controls the image forming apparatus 1. The system controller 13 includes, for example, a processor 21 and a memory 22.

[0026] The processor 21 is a computing element that performs arithmetic processing. The processor 21 is, for example, a CPU. The processor 21 performs various processes based on data such as programs stored in the memory 22. By executing the programs stored in the memory 22, the processor 21 functions as a control unit capable of performing various operations.

[0027] The memory 22 is a storage medium that stores programs and data used by the programs. Furthermore, the memory 22 also functions as a working memory. Specifically, the memory 22 temporarily stores data being processed by the processor 21 and programs being executed by the processor 21.

[0028] The processor 21 performs various information processing by executing programs stored in the memory 22. For example, the processor 21 generates a print job based on an image acquired from an external device via the communication interface 12. The processor 21 stores the generated print job in the memory 22.

[0029] A print job includes image data representing an image to be formed on a print medium P. The image data may be data for forming an image on one print medium P or may be data for forming images on multiple print media P. Furthermore, a print job includes information indicating color printing or monochrome printing.

[0030] Furthermore, the processor 21 functions as a controller (engine controller) that controls the operations of the transport unit 18, the image forming unit 19, and the fuser 20 by executing programs stored in the memory 22. Specifically, the processor 21 controls the transport of the print medium P by the transport unit 18, the formation of an image on the print medium P by the image forming unit 19, and the fixing of the image on the print medium P by the fuser 20.

[0031] Alternatively, the image forming apparatus 1 may include an engine controller separately from the system controller 13. In this case, the engine controller controls the transport of the print medium P by the transport unit 18, the formation of an image on the print medium P by the image forming unit 19, and the fixing of the image on the print medium P by the fixing unit 20. Furthermore, in this case, the system controller 13 supplies information necessary for control by the engine controller to the engine controller.

[0032] The display unit 14 includes a display that displays images based on image signals input from a display control unit such as the system controller 13 or a graphic controller (not shown). For example, the display unit 14 displays various settings for the image forming apparatus 1 and information such as the remaining toner level.

[0033] The operation interface 15 is connected to an operating component (not shown). The operation interface 15 supplies operation signals corresponding to the operation of the operating component to the system controller 13. The operating component may be, for example, a touch sensor, a keypad, a power button, a paper feed button, various function keys, or a keyboard. The touch sensor acquires information indicating a designated position within a certain area. The touch sensor is integrated with the display unit 14 as a touch panel and inputs a signal indicating the touched position displayed on the screen of the display unit 14 to the system controller 13.

[0034] Each of the plurality of paper trays 16 is a cassette for storing print media P. The paper trays 16 are configured to be able to supply the print media P from the outside of the housing 11 . For example, the paper trays 16 are configured to be able to be pulled out from the housing 11 .

[0035] The paper discharge tray 17 is a tray that supports the print medium P discharged from the image forming apparatus 1 .

[0036] Next, the configuration for transporting the printing medium P of the image forming apparatus 1 will be described.

[0037] The transport unit 18 is a mechanism for transporting the printing medium P within the image forming apparatus 1. Figure 1 As shown, the transport unit 18 includes a plurality of transport paths. For example, the transport unit 18 includes a paper feed transport path 31 and a paper discharge transport path 32.

[0038] The paper feed path 31 and paper discharge path 32 are each composed of multiple motors, multiple rollers, and multiple guides (not shown). Under the control of the system controller 13, the multiple motors rotate shafts, which in turn rotate the rollers in conjunction with the shafts. The rotation of the multiple rollers moves the print medium P. The multiple guides control the conveyance direction of the print medium P.

[0039] The paper feed conveyor path 31 receives print media P from the paper tray 16 and supplies the received print media P to the image forming unit 19. The paper feed conveyor path 31 includes pickup rollers 33 corresponding to each paper tray. Each pickup roller 33 receives print media P from the paper tray 16 into the paper feed conveyor path 31.

[0040] The paper discharge conveyance path 32 is a conveyance path for discharging the print medium P on which an image is formed from the housing 11 . The print medium P discharged from the paper discharge conveyance path 32 is supported by the paper discharge tray 17 .

[0041] Next, the image forming section 19 will be described.

[0042] The image forming unit 19 is a component that forms an image on the print medium P. Specifically, the image forming unit 19 forms an image on the print medium P based on the print job generated by the processor 21 .

[0043] The image forming unit 19 includes a plurality of loading units 41, a plurality of processing units 42, a plurality of exposure devices 43, and a transfer mechanism 44. The image forming unit 19 includes a loading unit 41 and an exposure device 43 for each processing unit 42. The plurality of processing units 42, the plurality of loading units 41, and the plurality of exposure devices 43 have the same configuration, so the following description uses one processing unit 42, one loading unit 41, and one exposure device 43 as an example.

[0044] Figure 2 This is an explanatory diagram for explaining an example of a configuration of a portion of the image forming section 19. First, the toner cartridge 2 mounted in the loading section 41 will be described.

[0045] like Figure 2 As shown, the toner cartridge 2 includes a toner storage container 51 , a toner delivery mechanism 52 , and a memory 53 .

[0046] The toner container 51 is a container for storing toner.

[0047] The toner delivery mechanism 52 is a mechanism for delivering the toner in the toner container 51. The toner delivery mechanism 52 is, for example, a spiral member provided in the toner container 51 and delivering the toner by rotating.

[0048] The memory 53 stores various control data in advance. The memory 53 is, for example, incorporated into an IC chip (not shown) and attached to the toner cartridge 2. Examples of control data stored in the memory 53 include an "identification code," a "toner supply motor total value," and a "near-end threshold." The "identification code" indicates the type and model of the toner cartridge 2. The "toner supply motor total value" is the cumulative value of the time the toner cartridge 2 is driven by the toner supply motor (described later). The "near-end threshold" is a threshold used by the image forming apparatus 1 to determine whether the remaining toner in the toner cartridge 2 is low.

[0049] Next, the loading portion 41 to which the toner cartridge 2 is mounted will be described.

[0050] like Figure 2 As shown, the loading sections 41 are each equipped with a module for filling the toner cartridge 2 with toner. Each of the multiple loading sections 41 includes a space for mounting the toner cartridge 2 and a toner replenishing motor 61. Furthermore, each of the multiple loading sections 41 includes a communication interface (not shown) that connects the memory 53 of the toner cartridge 2 to the system controller 13.

[0051] The toner supply motor 61 drives the toner delivery mechanism 52 of the toner cartridge 2 under the control of the processor 21. When the toner cartridge 2 is loaded into the loading section 41, the toner supply motor 61 is connected to the toner delivery mechanism 52 of the toner cartridge 2. The toner supply motor 61 rotates its shaft under the control of the processor 21, thereby driving the toner delivery mechanism 52 of the toner cartridge 2. By driving the toner delivery mechanism 52, the toner supply motor 61 supplies the toner in the toner container 51 to the developing device (described later).

[0052] Next, the processing unit 42 will be described.

[0053] The processing unit 42 is a component that forms a toner image. For example, multiple processing units 42 are provided for each type of toner. For example, multiple processing units 42 correspond to color toners such as cyan, magenta, yellow, and black. Specifically, a toner cartridge 2 containing a different color of toner is connected to each processing unit 42.

[0054] like Figure 2 As shown, the process unit 42 includes a photosensitive drum 71 , a cleaner 72 , a charger 73 , and a developer 74 .

[0055] The photosensitive drum 71 is a photosensitive body including a cylindrical drum and a photosensitive layer formed on the outer peripheral surface of the drum. The photosensitive drum 71 is rotated at a constant speed by a driving mechanism (not shown).

[0056] The cleaner 72 removes toner remaining on the surface of the photoconductive drum 71 .

[0057] The charger 73 uniformly charges the surface of the photosensitive drum 71. For example, the charger 73 uses a charging roller to apply a voltage to the photosensitive drum 71, thereby charging the photosensitive drum 71 with a uniform negative potential. The charging roller rotates as the photosensitive drum 71 rotates while applying a predetermined pressure to the photosensitive drum 71.

[0058] The developing device 74 is a device that causes toner to adhere to the photosensitive drum 71. The developing device 74 includes a developer container 81, a stirring mechanism 82, a developing roller 83, a doctor blade 84, an automatic toner control (ATC) sensor 85, and the like.

[0059] The developer container 81 is a container for storing developer including toner and carrier. The developer container 81 receives the toner delivered from the toner cartridge 2 by the toner delivery mechanism 52. The carrier is stored in the developer container 81 when the developing device 74 is manufactured.

[0060] The stirring mechanism 82 is driven by a motor (not shown) to stir the toner and the carrier in the developer container 81 .

[0061] The developing roller 83 rotates in the developer container 81 so that the developer adheres to the surface.

[0062] The scraper 84 is disposed at a predetermined distance from the surface of the developing roller 83. The scraper 84 removes a portion of the developer adhering to the surface of the rotating developing roller 83. As a result, a layer of developer having a thickness corresponding to the distance between the scraper 84 and the surface of the developing roller 83 is formed on the surface of the developing roller 83.

[0063] The ATC sensor 85 is, for example, a magnetic flux sensor having a coil and detecting a voltage generated by the coil. The detection voltage of the ATC sensor 85 varies depending on the density of the magnetic flux from the toner in the developer container 81. Specifically, the ATC sensor 85 detects a voltage corresponding to the concentration ratio of the toner to the carrier in the developer container 81 (simply referred to as "toner concentration"). The system controller 13 can determine the toner concentration in the developer container 81 based on the detection voltage of the ATC sensor 85.

[0064] Next, the exposure device 43 will be described.

[0065] The exposure device 43 includes multiple light-emitting elements. The exposure device 43 forms a latent image on the photosensitive drum 71 by irradiating light from the light-emitting elements onto the charged photosensitive drum 71. The light-emitting elements are, for example, light-emitting diodes (LEDs) or laser diodes (LDs). Each light-emitting element is configured to irradiate light onto a single point on the photosensitive drum 71. The multiple light-emitting elements are arranged in the main scanning direction, which is parallel to the rotation axis of the photosensitive drum 71.

[0066] The exposure device 43 irradiates light onto the photosensitive drum 71 using a plurality of light emitting elements arranged in the main scanning direction, thereby forming a latent image corresponding to one line on the photosensitive drum 71. The exposure device 43 forms a plurality of lines of latent images by continuously irradiating light onto the rotating photosensitive drum 71.

[0067] In the above configuration, when light is irradiated from the exposure device 43 onto the surface of the photosensitive drum 71, which has been charged by the charger 73, an electrostatic latent image is formed. When the developer layer formed on the surface of the developing roller 83 comes into contact with the surface of the photosensitive drum 71, the toner contained in the developer adheres to the latent image formed on the surface of the photosensitive drum 71. As a result, a toner image is formed on the surface of the photosensitive drum 71.

[0068] Next, the transfer mechanism 44 will be described.

[0069] The transfer mechanism 44 is a structure that transfers the toner image formed on the surface of the photosensitive drum 71 to the printing medium P.

[0070] like Figure 1 as well as Figure 2 As shown, the transfer mechanism 44 includes, for example, a primary transfer belt 91 , a secondary transfer counter roller 92 , a plurality of primary transfer rollers 93 , and a secondary transfer roller 94 .

[0071] The primary transfer belt 91 is an endless belt wound around a secondary transfer counter roller 92 and a plurality of winding rollers. The inner surface (inner circumference) of the primary transfer belt 91 contacts the secondary transfer counter roller 92 and the plurality of winding rollers, while the outer surface (outer circumference) faces the photosensitive drum 71 of the process unit 42.

[0072] The secondary transfer counter roller 92 is rotated by a motor (not shown). The rotation of the secondary transfer counter roller 92 transports the primary transfer belt 91 in a predetermined transport direction. The multiple winding rollers are configured to rotate freely. The multiple winding rollers rotate in conjunction with the movement of the primary transfer belt 91 by the secondary transfer counter roller 92d.

[0073] The plurality of primary transfer rollers 93 are configured to bring the photosensitive drums 71 of the process units 42 into contact with the primary transfer belt 91. The plurality of primary transfer rollers 93 are provided corresponding to the photosensitive drums 71 of the process units 42. Specifically, the plurality of primary transfer rollers 93 are positioned so as to face the corresponding photosensitive drums 71 of the process units 42, with the primary transfer belt 91 interposed therebetween. The primary transfer rollers 93 contact the inner circumference of the primary transfer belt 91, displacing the primary transfer belt 91 toward the photosensitive drums 71. This causes the primary transfer rollers 93 to bring the outer circumference of the primary transfer belt 91 into contact with the photosensitive drums 71.

[0074] The secondary transfer roller 94 is positioned opposite the primary transfer belt 91. The secondary transfer roller 94 contacts the outer circumference of the primary transfer belt 91 and applies pressure. This creates a transfer nip where the secondary transfer roller 94 is in close contact with the outer circumference of the primary transfer belt 91. When the print medium P passes through the transfer nip, the secondary transfer roller 94 presses the print medium P against the outer circumference of the primary transfer belt 91.

[0075] The secondary transfer roller 94 and the secondary transfer counter roller 92 rotate to sandwich the print medium P supplied from the paper feed path 31 , thereby conveying the print medium P. As a result, the print medium P passes through the transfer nip.

[0076] In the above-described configuration, when the outer peripheral surface of the primary transfer belt 91 contacts the photosensitive drum 71, the toner image formed on the surface of the photosensitive drum is transferred to the outer peripheral surface of the primary transfer belt 91. Figure 1 As shown, when the image forming unit 19 includes multiple process units 42, the primary transfer belt 91 receives toner images from the photosensitive drums 71 of the multiple process units 42. The toner image transferred to the outer peripheral surface of the primary transfer belt 91 is conveyed through the primary transfer belt 91 until it reaches the transfer nip where the secondary transfer roller 94 is in close contact with the outer peripheral surface of the primary transfer belt 91. If a print medium P is present in the transfer nip, the toner image transferred to the outer peripheral surface of the primary transfer belt 91 is transferred to the print medium P in the transfer nip.

[0077] Next, the fixing structure of the image forming apparatus 1 will be described.

[0078] The fuser 20 melts the toner transferred to the print medium P, thereby fixing the toner image. The fuser 20 operates under the control of the system controller 13. The fuser 20 includes a heating member for applying heat to the print medium P and a pressure member for applying pressure to the print medium P. For example, the heating member is a heat roller 95. Furthermore, for example, the pressure member is a pressure roller 96.

[0079] The heating roller 95 is a fixing rotating body rotated by a motor (not shown). The heating roller 95 comprises a hollow metal core and an elastic layer formed on the outer periphery of the metal core. The heating roller 95 is heated to a high temperature by a heater located inside the hollow metal core. The heater is, for example, a halogen heater. Alternatively, the heater may be an induction heating (IH) heater that heats the metal core by electromagnetic induction.

[0080] The pressure roller 96 is positioned opposite the heating roller 95. The pressure roller 96 includes a metal core formed of metal with a predetermined outer diameter and an elastic layer formed on the outer periphery of the metal core. The pressure roller 96 applies pressure to the heating roller 95 by applying stress from a tension member (not shown). By applying pressure from the pressure roller 96 to the heating roller 95, a gap (fixing gap) is formed in which the pressure roller 96 and the heating roller 95 are in close contact. The pressure roller 96 is rotated by a motor (not shown). As the pressure roller 96 rotates, it moves the print medium P that has entered the fixing gap and presses the print medium P against the heating roller 95.

[0081] With the above configuration, the heating roller 95 and the pressure roller 96 apply heat and pressure to the print medium P passing through the fixing nip. This fixes the toner image on the print medium P passing through the fixing nip. The print medium P passing through the fixing nip is introduced into the paper discharge conveyor 32 and discharged outside the housing 11. The fixing unit 20 is not limited to the above configuration. The fixing unit 20 may also be configured in a desired manner to apply heat to the print medium P, onto which the toner image has been transferred, via a film-like member, thereby melting the toner and fixing the image.

[0082] Next, control of the image forming apparatus 1 by the system controller 13 will be described.

[0083] Figure 3 This is a flowchart for explaining the process related to toner replenishment by the system controller 13 .

[0084] The processor 21 determines whether the toner cartridge 2 has been replaced (ACT 11). For example, the processor 21 determines that the toner cartridge 2 has been replaced when the lid of the loading unit 41 is opened. Alternatively, if a unique ID is stored in the toner cartridge 2, the processor 21 may determine that the toner cartridge 2 has been replaced when the ID of the toner cartridge 2 has changed. Alternatively, the processor 21 may detect replacement of the toner cartridge 2 using any other means.

[0085] When the processor 21 determines that the toner cartridge 2 has not been replaced (ACT 11 , NO), the process proceeds to ACT 13 to be described later.

[0086] Furthermore, when the processor 21 determines that the toner cartridge 2 has been replaced (ACT 11, YES), it reads data from the memory 53 of the toner cartridge 2 (ACT 12). For example, the processor 21 reads the "identification code," "toner supply motor total value," and "near-end threshold" from the memory 53 of the toner cartridge 2 and stores them in the memory 22 of the system controller 13.

[0087] For example, in the memory 53 of the toner cartridge 2, the "discriminator" is stored at address "B001," the "toner supply motor total value" is stored at address "B002," and the "near-end threshold" is stored at address "B003." In this case, the processor 21 stores the "discriminator" at address "A001" of the memory 22, the "toner supply motor total value" at address "A002," and the "near-end threshold" at address "A003."

[0088] Furthermore, the processor 21 executes a warm-up operation when the image forming apparatus 1 is powered on. During the warm-up operation, the processor 21 may read the "identification code," "toner supply motor total value," and "near-end threshold value" from the memory 53 of the toner cartridge 2 and store them in the memory 22.

[0089] The processor 21 checks the toner concentration in the developer container 81 based on the detection voltage of the ATC sensor 85 (ACT 13 ).

[0090] The processor 21 determines whether to replenish toner (ACT 14). The processor 21 determines whether to replenish toner based on the toner concentration in the developer container 81 confirmed in ACT 13 and a preset reference concentration. For example, if the toner concentration is lower than the reference concentration by a predetermined value or more, the processor 21 determines to cause the toner replenishment motor 61 to perform a toner replenishment operation.

[0091] When the processor 21 determines that toner replenishment is not to be performed (ACT 14 , NO), the process proceeds to ACT 18 to be described later.

[0092] When the processor 21 determines that toner replenishment is to be performed (ACT 14 , YES), it determines a toner replenishment mode (ACT 15 ). For example, the processor 21 determines one of a plurality of toner replenishment modes in which the driving time of the toner replenishment motor 61 is different according to the difference between the toner concentration and the reference concentration.

[0093] Specifically, the processor 21 determines that toner replenishment is not to be performed when toner concentration [%] - reference concentration [%] > -0.3 [%].

[0094] Furthermore, when -0.3 ≥ toner concentration [%] - reference concentration [%] > -0.6 [%], the processor 21 determines toner replenishment in the first replenishment mode in which the toner replenishment motor 61 is driven for a predetermined time.

[0095] Furthermore, the processor 21 determines that toner replenishment is to be performed in the second replenishment mode when −0.6≧toner density [%]−reference density [%]>−0.9 [%].

[0096] The second replenishment mode is a toner replenishment mode in which the toner replenishment motor 61 is driven for a longer time than that in the first replenishment mode.

[0097] Furthermore, when -0.9 ≥ toner concentration [%] - reference concentration [%] > -1.2 [%], the processor 21 determines toner replenishment in the third replenishment mode. The third replenishment mode is a toner replenishment mode in which the toner replenishment motor 61 is driven for a longer time than the second replenishment mode.

[0098] Furthermore, when -1.2 ≥ toner concentration [%] - reference concentration [%] > -1.5 [%], the processor 21 determines toner replenishment in the fourth replenishment mode, which drives the toner replenishment motor 61 for a longer time than the third replenishment mode.

[0099] Furthermore, when -1.5 ≥ toner concentration [%] - reference concentration [%], the processor 21 determines to perform toner replenishment in the fifth replenishment mode. The fifth replenishment mode is a toner replenishment mode in which the toner replenishment motor 61 is driven for a longer period than in the fourth replenishment mode. Furthermore, the fifth replenishment mode is a toner replenishment mode in which the toner replenishment motor 61 is driven for a longer period of time to significantly reduce the toner concentration in the developer container 81. Alternatively, the fifth replenishment mode may be a mode in which toner replenishment continues until the toner concentration [%] - reference concentration [%] reaches -1.5% or higher.

[0100] The processor 21 executes a toner supply operation using the determined toner supply mode (ACT 16 ). Specifically, the processor 21 controls the toner supply motor 61 to drive the toner delivery mechanism 52 of the toner cartridge 2 according to the determined toner supply mode.

[0101] The processor 21 totals the amount of time (drive time) the toner supply motor 61 is driven and accumulates this information as a toner supply motor total value (ACT 17). As described above, the toner supply motor total value is information stored at address "A002" of the memory 22 of the system controller 13. Each time the toner supply motor 61 is driven, the processor 21 totals the drive time and adds the total value to the value at address "A002" of the memory 22. Thus, the toner supply motor total value in the memory 22 of the system controller 13 sequentially accumulates the drive time of the toner supply motor 61.

[0102] The processor 21 determines whether to terminate the process (ACT 18 ). For example, when an operation to terminate the operation of the image forming apparatus 1 is performed, the processor 21 determines to terminate the process.

[0103] When the processor 21 determines that the processing has not been completed (ACT 18, No), it jumps to the processing of ACT 11. Thus, the processor 21 repeatedly executes the processing of ACT 11 to ACT 18.

[0104] When the processor 21 determines that the process is to be terminated (ACT 18, YES), the processor 21 writes the value of the address "A002" of the memory 22 of the system controller 13 to the address "B002" of the memory 53 of the toner cartridge 2, and terminates the process. Figure 3 Thus, the latest toner supply motor total is stored in the memory 53 of the toner cartridge 2 .

[0105] Figure 4 This is a flowchart for explaining the accumulation of pixel total values by the system controller 13 .

[0106] The processor 21 of the system controller 13 executes the Figure 4 For example, the processor 21 may also execute the process of printing each time a sheet of paper is printed. Figure 4 The processing structure can also be executed every time a printing task is completed. Figure 4 The processing structure can also be executed each time multiple printing is executed. Figure 4 In this example, the processor 21 executes the Figure 4 processing.

[0107] The processor 21 determines whether to execute printing (ACT 21 ).

[0108] When the processor 21 determines that printing is not to be executed (ACT 21 , NO), the process proceeds to ACT 24 to be described later.

[0109] When the processor 21 determines that printing is to be executed (ACT 21 , YES), it executes printing based on the image data for printing (ACT 22 ). That is, the processor 21 controls the transport unit 18 , the image forming unit 19 , and the fixing unit 20 to form an image on the printing medium P.

[0110] The processor 21 totals and accumulates the pixel values of the image data used for printing, and calculates the pixel total value (ACT23). The pixel value of the image data corresponds to the number of dots printed in each color. More specifically, the pixel value of the image data corresponds to the number of pixels drawn by the exposure device 43 on the photosensitive drum 71. That is, the processor 21 accumulates the number of printed dots into the pixel total value according to the color corresponding to each colorant cartridge 2. For example, the processor 21 stores the pixel total value in a specified area of the memory 22. The processor 21 executes printing, and each time the pixel value is totaled, the total pixel value is added to the pixel total value of the specified area of the memory 22. Thus, the pixel total value of the memory 22 of the system controller 13 is accumulated sequentially according to the printing situation and for each color of the colorant. In addition, the pixel value totaled and accumulated by the processor 21 is not limited to the number of dots printed as described above, and can be in any form as long as it is based on at least the amount of colorant used based on the image data reflection.

[0111] The processor 21 determines whether to terminate the process (ACT 24 ). For example, when an operation to terminate the operation of the image forming apparatus 1 is performed, the processor 21 determines to terminate the process.

[0112] When the processor 21 determines that the processing has not been completed (ACT 24, No), the process jumps to ACT 21. Thus, the processor 21 repeatedly executes the processes from ACT 21 to ACT 24.

[0113] In addition, when the processor 21 determines that the process is to be terminated (ACT 24, YES), the process ends. Figure 4 processing.

[0114] (First embodiment)

[0115] Next, the process of determining a toner container replenishment abnormality in the image forming apparatus 1 according to the first embodiment will be described. The image forming apparatus 1 determines a toner container replenishment abnormality and toner exhaustion in the toner cartridge 2 based on the pixel total value and the toner replenishment motor total value.

[0116] Figure 5 This is a flowchart for explaining determination of toner container replenishment abnormality and toner exhaustion by the system controller 13 .

[0117] The processor 21 of the system controller 13 executes the Figure 5 The processing interval is a unit of processing determined by the number of printed sheets, the total pixel value, or the total toner supply motor value.

[0118] For example, the processing interval is determined based on the number of printed sheets set in advance. Specifically, the processor 21 is configured to execute the processing interval every time 50 sheets are printed. Figure 5processing.

[0119] In addition, the processing interval may also be an interval until the pixel total value increases by a predetermined value. In this case, the processor 21 executes the processing interval every time the pixel total value increases by a predetermined value. Figure 5 processing.

[0120] In addition, for example, the processing interval may be an interval until the toner supply motor total increases by a predetermined value. In this case, the processor 21 executes the operation of the toner supply motor each time the toner supply motor total increases by a predetermined value. Figure 5 processing.

[0121] The processor 21 determines whether the preset processing interval has ended (ACT 31). In this example, the processing interval is determined based on the number of printed sheets. In this case, the processor 21 determines whether the preset number of printed sheets (for example, 50 sheets) has been printed.

[0122] When the processor 21 determines that the preset processing period has not ended (ACT 31 , No), the process proceeds to the process of ACT 41 described later.

[0123] When the processor 21 determines that the preset processing interval has ended (ACT 31, YES), it calculates the increase in the total pixel value during the processing interval (ACT 32). In other words, the processor 21 calculates the increase in the total pixel value during printing of a preset number of prints (e.g., 50 sheets).

[0124] The processor 21 also calculates the increase in the toner supply motor total value during the processing period (ACT 33 ). Specifically, the processor 21 calculates the increase in the toner supply motor total value during printing of a preset number of prints (eg, 50 sheets).

[0125] The processor 21 calculates the toner replenishment rate based on the increase in the pixel total value and the increase in the toner replenishment motor total value (ACT 34 ). That is, the processor 21 calculates the toner replenishment rate every time a processing interval ends.

[0126] The toner replenishment rate is the ratio of the toner usage during the processing interval to the toner replenishment amount. The toner usage can be estimated based on the pixel total value. The toner replenishment amount is estimated based on the drive time of the toner replenishment motor 61. The processor 21 calculates the toner replenishment rate based on the increase in the pixel total value during the processing interval and the increase in the toner replenishment motor total value. Specifically, the processor 21 calculates the toner replenishment rate by dividing the increase in the pixel total value by the increase in the toner replenishment motor total value. In other words, the toner replenishment rate is the ratio of the pixel total value to the toner replenishment motor total value.

[0127] Processor 21 calculates an average value of the printing ratios of the image data (ACT 35). The printing ratio is the ratio of the number of dots printed based on the image data to the number of dots that can be printed per unit area of the image by image forming apparatus 1. The unit area of the image in the printing ratio is, for example, the area corresponding to the print medium P. For example, processor 21 calculates the printing ratios of each of the plurality of image data used for printing in the processing interval to calculate the average value of the printing ratios. Alternatively, processor 21 may calculate a median value of the printing ratios, for example, rather than the average value of the printing ratios.

[0128] The processor 21 determines a toner replenishment rate threshold value as a threshold value for comparison with the toner replenishment rate based on the calculated average printing rate of the image data (ACT 36). The processor 21 determines the toner replenishment rate threshold value based on the average printing rate and a preset control table.

[0129] The toner replenishment rate threshold is a toner replenishment rate threshold that increases in accordance with an increase in the printing rate of image data in a processing section. Figure 6 This is an explanatory diagram for explaining an example of a toner replenishment rate threshold value. Figure 6 The horizontal axis represents the printing rate. Figure 6 The vertical axis represents the toner replenishment rate. Figure 6 The curve graph 97 shows the toner supply rate threshold value. Figure 6 As shown, the toner replenishment rate threshold is a value that increases or decreases according to the increase or decrease in the printing rate of image data in the processing period. For example, the toner replenishment rate threshold is a value proportional to the printing rate.

[0130] As described above, when the toner concentration in the developer container 81 is lower than the reference concentration by a specified value or more, the processor 21 drives the toner supply motor 61 in a supply mode corresponding to the difference, and supplies toner from the toner cartridge 2. When the difference between the toner concentration and the reference concentration is the same (within the same range), the supply mode is substantially the same, so there is no difference in the amount of increase in the toner supply motor total value. However, the pixel total value calculated based on the image data varies depending on the printing rate of the image data. For example, even when the toner concentration is higher than the reference concentration by a specified value or more in a state of low printing rate, the drive amount of the toner supply motor 61 does not change. Therefore, the toner supply motor total value is excessively accumulated. That is, when the printing rate is low, the toner supply rate is also reduced. Therefore, the toner supply rate threshold is set to be lower when the printing rate is low and higher when the printing rate is high.

[0131] The control table is information indicating the relationship between the printing rate and the toner replenishment rate threshold. For example, the control table may be configured to associate each printing rate with the toner replenishment rate threshold. That is, the control table sets the toner replenishment rate threshold based on the printing rate. Alternatively, the control table may be configured to associate multiple ranges defined by upper and lower limits of the printing rate with the toner replenishment rate threshold. Furthermore, the control table may be configured as a function indicating the proportional relationship between the printing rate of image data and the toner replenishment rate threshold.

[0132] The control table is stored in advance in the memory 22 of the system controller 13, for example. Alternatively, the control table may be stored in the memory 53 of the toner cartridge 2. In this case, the processor 21 may store the control table in the memory 53 of the toner cartridge 2, for example. Figure 3 At the timing of ACT 12 or other timing, the control table is read from the memory 53 of the toner cartridge 2 and stored in the memory 22 .

[0133] The processor 21 compares the determined toner supply rate threshold value with the calculated toner supply rate, and determines whether the toner supply rate is equal to or greater than the toner supply rate threshold value (ACT 37 ).

[0134] When the processor 21 determines that the toner replenishment rate is equal to or greater than the toner replenishment rate threshold value (ACT 37 , YES), the process proceeds to ACT 41 described later.

[0135] When the processor 21 determines that the toner replenishment rate is less than the toner replenishment rate threshold (ACT 37 , No), it determines whether the toner replenishment motor total value is greater than or equal to a preset toner replenishment motor threshold (ACT 38 ).

[0136] The toner supply motor threshold is a threshold value that is compared with the toner supply motor total value, that is, the cumulative value of the drive time of the toner supply motor 61. The toner supply motor threshold value is, for example, pre-stored in the memory 22 of the system controller 13. Alternatively, the toner supply motor threshold value may be, for example, a near-end threshold value. Specifically, the toner supply motor threshold value may be a value pre-stored in the memory 53 of the toner cartridge 2 and stored in the memory 22 of the system controller 13.

[0137] When the processor 21 determines that the toner replenishment motor total value is smaller than the preset toner replenishment motor threshold value (ACT 38 , No), it determines that the toner container replenishment is abnormal (ACT 39 ).

[0138] A toner container replenishment abnormality is an abnormality in the toner cartridge 2. Therefore, even if the toner replenishment motor is activated, toner cannot be replenished from the toner cartridge 2. Examples of abnormalities in the toner cartridge 2 include an abnormality in the toner delivery mechanism 52 of the toner cartridge 2, a sticking state of the sealant blocking the toner replenishment port of the toner cartridge 2, or a state in which the toner solidifies (sticking state) due to a high temperature within the toner cartridge 2 during storage. When such a toner container replenishment abnormality occurs, toner cannot be replenished from the toner cartridge 2 even if the toner replenishment motor 61 is activated, and therefore the toner concentration in the developer container 81 cannot be restored.

[0139] As described above, even though the toner replenishment motor total value remains high (less than the toner replenishment motor threshold), if the toner replenishment rate is less than the toner replenishment rate threshold, the processor 21 determines that a toner container replenishment abnormality has occurred. For example, the processor 21 causes the display unit 14 to display a message indicating a toner container replenishment abnormality. This allows the processor 21 to prompt the user to check for abnormalities in the toner delivery mechanism 52, any sealant blocking the toner replenishment port of the toner cartridge 2, or any toner adhesion within the toner cartridge 2.

[0140] Furthermore, when the processor 21 determines that the toner replenishing motor total value is equal to or greater than a preset toner replenishing motor threshold value (ACT 38 , YES), it determines that the toner is empty (ACT 40 ).

[0141] When the toner remaining in the toner cartridge 2 is low, the toner replenishment rate gradually decreases. This is because the toner supply amount per driving amount of the toner delivery mechanism 52 of the toner cartridge 2 decreases as the toner in the toner cartridge 2 decreases, and the driving time of the toner replenishment motor 61 for supplying the same amount of toner becomes longer.

[0142] When the toner replenishment motor total value has increased sufficiently (to be greater than the toner replenishment motor threshold), and the toner replenishment rate is less than the toner replenishment rate threshold, the processor 21 determines that the toner is exhausted, that is, no toner remains in the toner cartridge 2. For example, the processor 21 causes the display unit 14 to display a message indicating that the toner is exhausted. Thus, the processor 21 can notify the user that no toner remains in the toner cartridge 2.

[0143] Furthermore, the processor 21 performs a toner end determination based on the detection results of the ATC sensor 85, which is different from ACT 40. For example, the processor 21 determines that the toner is out if the difference between the toner concentration and the reference concentration is greater than a preset value (e.g., a difference <-1.5%) and the toner concentration cannot be restored even after forced replenishment. The processor 21 may also determine that the toner is out based on either or both of the toner end determination based on the detection results of the ATC sensor 85 and the toner end determination in ACT 40.

[0144] The processor 21 determines whether to terminate the process (ACT 41 ). For example, when an operation to terminate the operation of the image forming apparatus 1 is performed, the processor 21 determines to terminate the process.

[0145] When the processor 21 determines that the processing has not been completed (ACT 41 , NO), the process jumps to ACT 31 . Thus, the processor 21 repeatedly executes the processes from ACT 31 to ACT 41 .

[0146] In addition, when the processor 21 determines that the process is to be terminated (ACT41, YES), the process ends. Figure 5 processing.

[0147] As described above, the processor 21 of the system controller 13 of the image forming apparatus 1 according to the first embodiment calculates the toner replenishment rate based on the pixel total value, which is the cumulative value of the pixel values of the image data, and the toner replenishment motor total value, which is the cumulative value of the drive time of the toner replenishment motor 61. The processor 21 detects a toner container replenishment abnormality based on the calculated toner replenishment rate and the printing rate of the image data.

[0148] With this configuration, the image forming apparatus 1 can detect at an early stage that toner cannot be replenished from the toner cartridge 2 based on the toner replenishment rate, taking into account the printing rate. As a result, the image forming apparatus 1 can prompt the user to check for abnormalities in the toner delivery mechanism 52, sealing material clogging the toner replenishment port of the toner cartridge 2, toner adhesion within the toner cartridge 2, and the like.

[0149] Furthermore, the processor 21 detects a toner container replenishment abnormality when the toner replenishment motor total value is less than a preset toner replenishment motor threshold (e.g., a near-end threshold) and the toner replenishment rate is less than the toner replenishment rate threshold. Furthermore, the processor 21 detects toner end when the toner replenishment motor total value is greater than or equal to a preset toner replenishment motor threshold and the toner replenishment rate is less than the toner replenishment rate threshold.

[0150] With this configuration, the image forming apparatus 1 can determine whether the state in which toner cannot be replenished from the toner cartridge 2 is due to a shortage of toner in the toner cartridge 2 or a malfunction in the toner cartridge 2 .

[0151] (Second embodiment)

[0152] Next, a description will be given of a process related to determination of a toner container replenishment abnormality in the image forming apparatus 1 according to the second embodiment. Since the first and second embodiments do not differ in hardware configuration, the difference in control content will be described.

[0153] Figure 7 This is a flowchart for explaining determination of toner container replenishment abnormality and toner exhaustion performed by the system controller 13 according to the second embodiment.

[0154] The processor 21 determines whether the preset processing period has ended (ACT 51 ).

[0155] When the processor 21 determines that the preset processing period has not ended (ACT 51 , No), the process jumps to the process of ACT 63 described later.

[0156] When the processor 21 determines that the preset processing interval has ended (ACT 51 , Yes), it calculates the amount of increase in the pixel total value in the processing interval (ACT 52 ).

[0157] Furthermore, the processor 21 calculates the amount of increase in the toner supply motor total value during the processing period (ACT 53 ).

[0158] The processor 21 calculates the toner replenishment rate based on the amount of increase in the pixel total value and the amount of increase in the toner replenishment motor total value (ACT 54 ).

[0159] The processor 21 calculates an average value of the printing ratios of the image data (ACT 55 ).

[0160] The processor 21 determines a toner replenishment rate threshold value as a threshold value to be compared with the toner replenishment rate based on the calculated average value of the printing rates of the image data (ACT 56 ).

[0161] The processor 21 compares the determined toner supply rate threshold with the calculated toner supply rate, and determines whether the toner supply rate is equal to or greater than the toner supply rate threshold (ACT 57 ).

[0162] When the processor 21 determines that the toner replenishment rate is equal to or greater than the toner replenishment rate threshold value (ACT 57 , YES), the process proceeds to ACT 63 to be described later.

[0163] When the processor 21 determines that the toner replenishment rate is less than the toner replenishment rate threshold (ACT 57 , No), it determines whether the toner replenishment motor total value is greater than or equal to a preset toner replenishment motor threshold (intermediate count threshold) (ACT 58 ).

[0164] The intermediate count threshold is a type of toner supply motor threshold and is a threshold that is compared with the toner supply motor total value, that is, the cumulative value of the drive time of the toner supply motor 61. The intermediate count threshold is, for example, pre-stored in the memory 22 of the system controller 13. Alternatively, the intermediate count threshold may be a value pre-stored in the memory 53 of the toner cartridge 2 and stored in the memory 22 of the system controller 13. For example, when the toner cartridge 2 is replaced or the power is turned on, the processor 21 of the system controller 13 reads the intermediate count threshold from the memory 53 of the toner cartridge 2 and stores it in the memory 22.

[0165] If the processor 21 determines that the toner supply motor total value is less than the intermediate count threshold (ACT 58, No), it determines that a toner container replenishment error has occurred (the sealing material has not been removed) (ACT 59). In this case, the processor 21 causes the display unit 14 to display a message indicating a toner container replenishment error or a message urging the user to remove the sealing material. This allows the processor 21 to urge the user to identify the sealing material blocking the toner supply port of the toner cartridge 2.

[0166] When the processor 21 determines that the toner supply motor total value is equal to or greater than the intermediate count threshold (ACT 58 , YES), it determines whether the toner supply motor total value is equal to or greater than a preset toner supply motor threshold (imminent end threshold) (ACT 60 ).

[0167] If the processor 21 determines that the toner supply motor total value is less than the near-end threshold (ACT 60, No), it determines that there is a toner container replenishment abnormality, that is, an abnormality exists in the toner delivery mechanism 52 of the toner cartridge 2, or that the toner in the toner cartridge 2 is in a solidified state (sticking state) (ACT 61). In this case, the processor 21 causes the display unit 14 to display a message indicating that there is an abnormality in the toner delivery mechanism 52 of the toner cartridge 2, or that the toner in the toner cartridge 2 is in a solidified state (sticking state). This allows the processor 21 to prompt the user to confirm the abnormality in the toner delivery mechanism 52 or the sticking state of the toner in the toner cartridge 2.

[0168] Furthermore, if the processor 21 determines that the toner supply motor total value is equal to or greater than the near-end threshold (ACT 60, YES), it determines that the toner is exhausted (ACT 62). In this case, the processor 21 causes the display unit 14 to display a message indicating that the toner is exhausted. This allows the processor 21 to notify the user that no toner remains in the toner cartridge 2.

[0169] The processor 21 determines whether to terminate the process (ACT 63 ). For example, when an operation to terminate the operation of the image forming apparatus 1 is performed, the processor 21 determines to terminate the process.

[0170] When the processor 21 determines that the processing has not been completed (ACT 63 , No), the process jumps to ACT 51 . Thus, the processor 21 repeatedly executes the processes from ACT 51 to ACT 63 .

[0171] In addition, when the processor 21 determines that the process is to be terminated (ACT63, YES), the process ends. Figure 7 processing.

[0172] As described above, the processor 21 of the system controller 13 of the image forming apparatus 1 in the second embodiment determines that a toner container replenishment error has occurred when the toner replenishment motor total count is less than a preset intermediate count threshold and the toner replenishment rate is less than a toner replenishment rate threshold. Furthermore, the processor 21 urges the user to remove the sealant. This allows the user to be notified at an early stage of the sealant sticking to the toner supply port of the toner cartridge 2.

[0173] Furthermore, if the toner supply motor total count is less than or equal to a preset intermediate count threshold, reaching the near-end threshold, and the toner supply rate is less than the toner supply rate threshold, the processor 21 determines that a toner container replenishment abnormality has occurred. Furthermore, the processor 21 urges the user to check the toner delivery mechanism 52 of the toner cartridge 2 or to check for toner adhesion within the toner cartridge 2. This allows the user to be notified of any abnormality within the toner cartridge 2 at an early stage.

[0174] Furthermore, the toner replenishment motor threshold value can be further refined, thereby making it possible to notify the user of various conditions or to add items that urge the user to confirm.

[0175] Furthermore, the functions described in the above embodiments are not limited to being configured using hardware, but may be implemented using software by reading a program describing each function into a computer.

[0176] Although several embodiments of the present invention have been described, these embodiments are provided for illustrative purposes only and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the scope of the invention. These embodiments and their variations are included within the scope and spirit of the invention and are also included within the scope of the invention described in the claims and their equivalents.

Claims

1. An image forming apparatus comprising: Photosensitive drum; an exposure device for exposing the photosensitive drum based on image data; a developer for forming a toner image on the photosensitive drum using toner supplied from a toner cartridge; a toner concentration sensor for detecting a toner concentration in the developer; a toner supply motor for supplying toner from the toner cartridge to the developer based on the toner concentration; as well as A processor detects abnormal replenishment of a colorant container based on a colorant replenishment rate and a printing rate of the image data, wherein the colorant replenishment rate is calculated based on a pixel total value which is a cumulative value of pixel values of the image data and a colorant replenishment motor total value which is a cumulative value of the driving time of the colorant replenishment motor, and is a ratio of the pixel total value to the colorant replenishment motor total value, and the printing rate of the image data is a ratio of the number of dots printed based on the image data to the number of dots printed per unit area of each image.

2. The image forming apparatus according to claim 1, wherein The processor calculates the toner replenishment rate based on an increase in the pixel total value and an increase in the toner replenishment motor total value in a predetermined processing interval. determining a toner replenishment rate threshold value based on a printing rate of the image data in the processing section; When the toner replenishment rate is less than the toner replenishment rate threshold, a toner container replenishment abnormality is detected.

3. The image forming apparatus according to claim 2, wherein: The processor detects a toner container replenishment abnormality when the toner replenishment motor total value is less than a preset toner replenishment motor threshold and the toner replenishment rate is less than the toner replenishment rate threshold. The processor detects toner end when the toner supply motor total value is equal to or greater than a preset toner supply motor threshold and the toner supply rate is less than the toner supply rate threshold.

4. The image forming apparatus according to claim 2 or 3, wherein: The toner replenishment rate threshold is a value that becomes lower when the printing rate of the image data in the processing period is low, and becomes higher when the printing rate is high.

5. A method for controlling an image forming apparatus, wherein: The image forming apparatus comprises: a photosensitive drum; an exposure device for exposing the photosensitive drum based on image data; a developer for forming a toner image on the photosensitive drum using toner supplied from a toner cartridge; a toner concentration sensor for detecting a toner concentration in the developer; and a toner supply motor for supplying toner from the toner cartridge to the developer based on the toner concentration. and the processor, The processor detects abnormal replenishment of the colorant container based on the colorant replenishment rate and the printing rate of the image data, wherein the colorant replenishment rate is calculated based on the pixel total value which is the cumulative value of the pixel values of the image data and the colorant replenishment motor total value which is the cumulative value of the driving time of the colorant replenishment motor, and is the ratio of the pixel total value to the colorant replenishment motor total value, and the printing rate of the image data is the ratio of the number of dots printed based on the image data to the number of dots printed per unit area of each image.

Images