JP5975451B1 - Image forming apparatus - Google Patents

Abstract

Deterioration of a developer is suppressed by suppressing driving of an agitating member in the container provided inside the developer container and stirring the developer in the developer container within a range that does not hinder the supply of the developer. Prevent and save power. An image forming apparatus includes a magnetic sensor that outputs an ON signal when a magnetic field strength of a magnetic material is higher than a predetermined level, and a container that houses a new developer G1 inside the developer container. A main body, a container rotation shaft portion 303 rotatably supported by the container main body, and a container rotation shaft portion 303 are attached to the container rotation shaft portion 303 and supplied to the inside of the housing 302 while stirring the new developer G1 by the rotation of the container rotation shaft portion 303. A container agitating member 304, and when the length of the ON signal exceeds a predetermined first threshold value, the container rotation shaft portion 303 is rotated by a certain amount. [Selection] Figure 1

Description

  The present invention relates to an image forming apparatus that forms an image on a recording material using a developer.

  2. Description of the Related Art Conventionally, as an image forming apparatus such as a copying machine, a printer, or a facsimile machine, a process cartridge in which a photosensitive member and process means acting on the photosensitive member are integrated is detachably attached to a main body of the image forming apparatus. ing. Such a process cartridge includes a developer container filled with a developer such as toner, and an image forming unit that forms an image on a recording material with a photoconductor using the developer supplied from the developer container. Yes.

  Patent Document 1 relates to an image forming apparatus, in which a baffle provided inside a toner bottle containing toner rotates together with the toner bottle, thereby discharging the toner contained in the toner bottle from a discharge port of the toner bottle. A configuration for supplying to a developing device is disclosed. As described above, the conventional image forming apparatus includes an in-container stirring member such as a baffle for supplying the developer while stirring the developer container such as a toner bottle.

JP 2014-59356 A

  However, in the conventional image forming apparatus, the drive motor is always driven to rotate the stirring member in the container during the operation of the image forming apparatus, so that the developer in the developer container is deteriorated and power saving cannot be achieved. Has the problem. In particular, when the capacity of the developer container is large, since it takes time to use up the developer in the developer container, the developer in the developer container is significantly deteriorated.

  An object of the present invention is to provide a developer by suppressing the drive of an in-container stirring member that is provided inside the developer container and stirs the developer in the developer container within a range that does not hinder the supply of the developer. It is an object of the present invention to provide an image forming apparatus that can prevent deterioration of the image and save power.

An image forming apparatus according to the present invention is an image forming apparatus that forms an image on a recording material using a developer, and includes a housing that accommodates the developer therein, and a housing that is mounted on the housing and accommodated therein. A developer container for supplying the new developer into the housing; and a developer carrier that is housed in the housing and carries the developer to develop an electrostatic latent image, The housing temporarily stores a developer for supplying a developer to be supplied to the developer carrier, and a developer to be supplied from the developer container to the first developer storage chamber. A second developer accommodating chamber and a container accommodating portion for accommodating the developer container are formed, and further, a first rotating shaft portion rotatably installed in the first developer accommodating chamber, and the first A rotating shaft is attached to the first developer accommodating chamber by rotation of the first rotating shaft. A first stirring member for stirring the developer, a second rotating shaft portion rotatably installed in the second developer containing chamber, and the second rotating shaft portion attached to the second rotating shaft portion. A second agitating member that supplies the first developer accommodating chamber while agitating the developer accommodated in the second developer accommodating chamber by rotation of the second rotating shaft portion, and the second rotating shaft portion . while rotating by being pressed by stirring member, a rotating member to free fall to the upper surface of the current image agent stored in the second developer accommodating chamber when exceeding the top dead center, it is provided on the rotary member magnetic And an ON signal is output when the magnetic field strength of the magnetic body is equal to or higher than a predetermined level, and an OFF signal is output when the magnetic field strength is lower than the predetermined level. A magnetic sensor and a base on which the magnetic sensor is mounted; And a control unit that controls the operation of each part, and the developer container contains a container main body that contains the new developer, A container rotation shaft portion rotatably supported by the container body, and attached to the container rotation shaft portion, and the new developer is supplied to the second developer storage chamber while stirring the new developer by the rotation of the container rotation shaft portion. An agitation member in the container, and when the length of the ON signal exceeds a predetermined first threshold, the control unit rotates the container rotation shaft part by a certain amount , and When the length of the next ON signal after rotation exceeds the first threshold, a first message indicating that the remaining amount of the developer is low is displayed on the display unit, and the length of the ON signal Exceeds a second threshold that is longer than the first threshold. In this case, the printing operation is stopped, and a second message that prompts replacement of the developer container is displayed on the display unit .

  According to the present invention, the developer is controlled by suppressing the driving of the in-container stirring member that is provided inside the developer container and stirs the developer in the developer container within a range that does not hinder the supply of the developer. It is possible to prevent deterioration of the battery and to save power.

Sectional drawing of the image forming apparatus which concerns on embodiment of this invention The perspective view of the process cartridge which concerns on embodiment of this invention The perspective view of the stirring blade which concerns on embodiment of this invention The perspective view of the stirring blade which concerns on embodiment of this invention Relationship between weight of developer and developer weight M according to an embodiment of the present invention FIG. 3 is a flowchart showing the operation of the image forming apparatus according to the embodiment of the invention. The flowchart which shows the display process which concerns on embodiment of this invention

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

<Configuration of image forming apparatus>
The configuration of the image forming apparatus 100 according to an embodiment of the present invention will be described in detail below with reference to FIG.

  The image forming apparatus 100 includes a main body 101 and a process cartridge 102. A process cartridge 102 is detachably attached to the main body 101. The process cartridge 102 is a unit in which a photoconductor and process means acting on the photoconductor are integrated.

<Configuration of main unit>
The configuration of the main body 101 in the embodiment of the present invention will be described in detail below with reference to FIG.

  The main body unit 101 includes a support unit 201, a substrate 202, and a magnetic sensor 203.

  The support unit 201 is a part of the housing of the main body unit 101, and has a configuration in which the substrate 202 can be attached to the upper end thereof. A plurality of support portions 201 are provided in the depth direction of the image forming apparatus 100. When the process cartridge 102 is mounted on the image forming apparatus 100, the depth direction of the image forming apparatus 100 is the same as the axial direction of the rotation shaft portion 305 described later.

  The substrate 202 is fixed to the upper end of one of the support portions 201 by welding. Various electronic circuits including the magnetic sensor 203 are mounted on the substrate 202. The support unit 201 to which the substrate 202 is attached is appropriately determined depending on the model, specification, brand, destination, etc. of the image forming apparatus 100.

  The magnetic sensor 203 is typically a Hall element and is mounted on the substrate 202. The magnetic sensor 203 is provided below a developer storage chamber 302b in which a rotating member 309, which will be described later, is provided, and detects the strength of the magnetic field by the magnetic body 316 provided in the rotating member 309. The magnetic sensor 203 outputs a high potential signal (ON signal) when the intensity of the magnetic field exceeds a predetermined level. On the other hand, the magnetic sensor 203 outputs a low potential signal (OFF signal) when the intensity of the magnetic field is less than a predetermined level.

<Configuration of process cartridge>
The configuration of the process cartridge 102 according to the embodiment of the present invention will be described in detail below with reference to FIGS.

  The process cartridge 102 includes a developer container 301, a case 302, a container rotation shaft portion 303, an in-container stirring member 304, a rotation shaft portion 305, a stirring member 306, a rotation shaft portion 307, and a stirring member 308. A rotating member 309, a scraper 310, a supply roller 311, a developing roller 312, and a photoreceptor 313.

  The developer container 301 is attached to the housing 302. The developer container 301 is attached to the container main body 300 that contains the new developer G1 therein, the container rotation shaft portion 303 that is rotatably supported by the container main body 300, and the container rotation shaft portion 303. And an in-container stirring member 304 that supplies the new developer G1 to the inside of the housing 302 while stirring the new developer G1. The amount of the developer G1 accommodated in the developer container 301 is exemplified here as 500 g. The developer G1 accommodated in the developer container 301 is preferably a single component.

  The housing 302 is configured to accommodate the developer therein. The housing 302 includes a developer container storage unit 302a that stores the developer container 301, a developer storage chamber 302b that temporarily stores the developer G2 supplied from the developer container 301, and a second developer storage chamber. A developer storage chamber 302c which is a first developer storage chamber for storing the developer G3 supplied from the developer storage chamber 302b. The developer G2 stored in the developer storage chamber 302b is supplied to the developer storage chamber 302c. The developer G3 stored in the developer storage chamber 302c is supplied to the developing roller 312. The maximum amount of developer G3 that can be stored in the developer storage chamber 302c is larger than the maximum amount of developer G2 that can be stored in the developer storage chamber 302b.

  The container rotation shaft portion 303 is rotatably supported with respect to the developer container 301 and is rotated by a rotational driving force of a motor (not shown). The container rotation shaft 303 starts rotating when the motor starts driving when a predetermined condition is satisfied, and then stops after rotating by a certain amount.

  The in-container stirring member 304 is attached to the container rotation shaft portion 303 inside the developer container 301 and rotates by the rotation of the container rotation shaft portion 303 to stir the developer G1 accommodated in the developer container 301. Then, it is supplied to the developer storage chamber 302b. The in-container stirring member 304 starts rotating together with the container rotation shaft portion 303 and rotates after a certain amount, and then stops. The details of the operations of the container rotation shaft portion 303 and the in-container stirring member 304 will be described in the description of the operation of the image forming apparatus 100 described later.

  The rotation shaft portion 305 as the second rotation shaft portion is rotatably supported with respect to the developer storage chamber 302b, and is rotated by a rotation driving force of a motor (not shown).

  The agitating member 306 as the second agitating member is attached to the rotating shaft portion 305 inside the developer accommodating chamber 302b, and is rotated by the rotation of the rotating shaft portion 305, so that the developer accommodated in the developer accommodating chamber 302b. G2 is stirred and conveyed to the developer storage chamber 302c. As shown in FIG. 4, the stirring member 306 is a stirring blade that is a second stirring blade that is elastically deformable parallel to the central axis of the rotating shaft portion 305 on the outer end surface farthest from the central axis of the rotating shaft portion 305. Feathers 314 are provided. The stirring blade 314 has a notch 319 that does not hit the edge of the opening 318 of the developer storage chamber 302 b that communicates with the inside of the developer container 301. The stirring blade 314 rotates together with the stirring member 306 to stir the developer G2 in the developer storage chamber 302b while scraping off the developer G2 remaining on the inner bottom surface of the developer storage chamber 302b. The developer G2 is transported to the storage chamber 302c.

  The rotation shaft portion 307 that is the first rotation shaft portion is rotatably supported with respect to the developer storage chamber 302c, and is rotated by a rotation driving force of a motor (not shown). The torque of the rotating shaft part 307 is larger than the torque of the rotating shaft part 305.

  The agitating member 308 that is the first agitating member is attached to the rotating shaft portion 307 inside the developer accommodating chamber 302c, rotates by the rotation of the rotating shaft portion 307, and is stored in the developer accommodating chamber 302c. G3 is stirred. As shown in FIG. 3, the stirring member 308 is a first stirring blade that is elastically deformable at the outer end surface farthest from the central axis of the rotating shaft portion 307 and parallel to the central axis of the rotating shaft portion 307. Feathers 315 are provided. The stirring blade 315 rotates together with the stirring member 308 and scrapes off the developer G3 remaining on the inner bottom surface of the developer storage chamber 302c.

  The rotating member 309 is provided with a magnetic body 316. The rotating member 309 is loosely fitted to the rotating shaft portion 305 and is rotated by being pressed by the stirring member 306 from the rear with respect to the rotation direction of the stirring member 306. When the rotating member 309 exceeds the top dead center, the rotating member 309 falls freely by its own weight regardless of the stirring member 306. In the rotating member 309, when the weight of the developer G2 accommodated in the developer accommodating chamber 302b is equal to or less than Mg, the magnetic sensor 203 detects the magnetic field of the magnetic body 316 when the rotating member 309 falls freely. A metal weight 317 adjusted to the above is attached. When the rotating member 309 falls freely beyond the top dead center, the rotating member 309 enters the developer G2 below the developer G2 or a predetermined distance from the upper surface of the developer G2 according to the weight of the weight 317. It stops in the state. Then, when the stirring member 306 rotates and catches up with the rotating member 309, the rotating member 309 rotates while stirring the developer stored in the developer storage chamber 302b by being pressed again from behind by the stirring member 306. To do.

  Here, M can be selected according to the required specifications, and is preferably 50 g to 70 g. Therefore, the weight of the weight 317 is preferably 2.5 g to 5.2 g from FIG. In this way, by adjusting the weight of the weight 317, the threshold value to be compared with the length of the ON signal output from the magnetic sensor 203 in order to replenish the developer or replace the developer container 301 is adjusted. Can do.

  The scraper 310 is provided in parallel to the central axis of the rotating shaft portion 307 in the vicinity of the boundary surface that connects the developer storage chamber 302b and the developer storage chamber 302c of the housing 302. The scraper 310 scrapes off the developer on the stirring blade 315 and drops it into the developer storage chamber 302c.

  The supply roller 311 rotates to supply the developer stored in the developer storage chamber 302 c to the developing roller 312.

  The developing roller 312 which is a developer carrying member is applied with a negative or positive potential, and gives a negative or positive charge to the developer supplied by the replenishing roller 311. The developing roller 312 is accommodated in the housing 302 and rotates to carry a negatively or positively charged developer and supply it to the photoconductor 313, thereby forming an electrostatic latent image formed on the photoconductor 313. Develop the image.

  The photosensitive member 313 scans the charged surface with a laser beam to form an electrostatic latent image, and forms a developer image from the electrostatic latent image with the developer supplied from the developing roller 312. The photoconductor 313 presses and sandwiches the conveyed recording material (not shown) with a pressure roller (not shown) at a predetermined temperature, and transfers the developer image to the recording material to form an image.

<Operation of Image Forming Apparatus>
The operation of the image forming apparatus 100 according to the present embodiment will be described in detail below with reference to FIG.

  A control unit (not shown) of the image forming apparatus 100 starts an initial operation or a printing operation when the main power supply is turned on (S1).

  The agitating member 306 rotates together with the rotating shaft portion 305 by the rotational driving force of the motor, and agitates the developer G2. Further, the stirring member 308 rotates together with the rotating shaft portion 307 by the rotational driving force of the motor, and stirs the developer G3. The in-container stirring member 304 stops rotating together with the container rotation shaft portion 303.

  The rotating member 309 is pressed by the stirring member 306 from the rear with respect to the rotation direction of the stirring member 306, rotates together with the stirring member 306 up to the top dead center, and freely falls when the top dead center is exceeded. When the rotating member 309 falls freely beyond the top dead center, the rotating member 309 enters the developer G2 below the developer G2 or a predetermined distance from the upper surface of the developer G2 according to the weight of the weight 317. It stops in the state. Then, when the stirring member 306 rotates and catches up with the rotating member 309, the rotating member 309 rotates while stirring the developer stored in the developer storage chamber 302b by being pressed again from behind by the stirring member 306. To do.

  In the process of rotation of the rotating member 309, when the magnetic body 316 reaches the detection range of the magnetic sensor 203 and the strength of the magnetic field by the magnetic body 316 becomes a predetermined level or higher, the magnetic sensor 203 has a high potential. A signal (ON signal) is output. The magnetic sensor 203 outputs a low-potential signal (OFF signal) when the magnetic body 316 leaves the detection range of the magnetic sensor 203 and the intensity of the magnetic field by the magnetic body 316 falls below a predetermined level.

  In this case, the smaller the remaining amount of the developer G2 stored in the developer storage chamber 302b, the longer the period during which the magnetic body 316 exists within the detection range of the magnetic sensor 203. Therefore, it is possible to easily determine the remaining amount of the developer G2 by determining the detection length of the ON signal.

  The control unit determines whether or not the detection length of the ON signal exceeds a predetermined first threshold (S2).

  When the detection length of the ON signal is equal to or less than the first threshold (S2: NO), the control unit returns to the process of S1.

  On the other hand, when the detection length of the ON signal exceeds the first threshold (S2: YES), the control unit starts the rotation of the container rotation shaft portion 303 and the container stirring member 304, and then the container rotation shaft portion 303. In addition, the stirring member 304 in the container is stopped after being rotated by a certain amount. Thereby, stirring and replenishment of the developer G1 is started, and the developer G1 accommodated in the developer container 301 is supplied to the developer accommodating chamber 302b while being agitated (S3). Thus, by suppressing the drive of the in-container stirring member 304 within a range that does not hinder the supply of the developer G1, the deterioration of the developer G1 can be prevented and the power can be saved.

  The control unit again determines whether or not the detection length of the ON signal exceeds a predetermined first threshold (S4). This process is performed to determine whether or not the developer G1 stored in the developer container 301 is exhausted.

  When the detection length of the ON signal is equal to or smaller than the first threshold (S4: NO), the control unit determines that the developer G1 is supplied from the developer container 301 and returns to the process of S1.

  On the other hand, when the detection length of the ON signal exceeds the first threshold (S4: YES), the control unit executes display processing (S5). Such display processing is executed according to the following procedure.

<Display processing>
The display processing according to the present embodiment will be described in detail below with reference to FIG.

  A control unit (not shown) of the image forming apparatus 100 displays a toner near empty display indicating that the remaining amount of developer is low on a display unit (not shown) (S11).

  The control unit sets the number of printable sheets N with the current remaining amount of developer (S12). The number of printable sheets N can be adjusted by the weight of the weight 317 provided on the rotating member 309, and is preferably 3000 to 5000 sheets (N = 3000 to 5000). The control unit decrements the value of the printable number N every time printing is performed.

  The control unit determines whether or not the detection length of the ON signal exceeds a predetermined second threshold (S13). Here, the second threshold value is larger than the first threshold value (second threshold value> first threshold value).

  When the detected length of the ON signal is equal to or smaller than the second threshold (S13: NO), the control unit determines whether the value of the printable number N is “0” (S14).

  When the value of the printable number N is other than “0” (S14: NO), the control unit returns to the process of S11.

  On the other hand, when the value of the printable sheet number N is “0” (S14: YES), the control unit stops the printing operation and displays a display prompting replacement of the developer container 301 on a display unit (not shown) ( S15).

  Further, when the detection length of the ON signal exceeds the second threshold (S13: YES), the control unit stops the printing operation and performs a display prompting replacement of the developer container 301 (S15).

  In this embodiment, the determination in S13 is omitted, and after displaying the toner near empty display in S11, the control unit performs control based only on the pixel counts in S12 and S14, and the number of printable sheets. If the value of N is “0” (S14: YES), the printing operation may be stopped and a display for prompting replacement of the developer container 301 may be displayed on a display unit (not shown) (S15).

  As described above, according to the present embodiment, the rotation shaft portion 305 that is rotatably installed in the developer storage chamber 302b, and the developer G2 that is stored in the developer storage chamber 302b by the rotation of the rotation shaft portion 305. Agitating member 306 that is supplied to developer containing chamber 302c while being stirred, and loosely fitted to rotating shaft portion 305, pressed against rotating by agitating member 306, and rotated when the top dead center is exceeded. A rotating member 309 that freely drops to the upper surface of the developer G2 contained in the image forming apparatus 100, and a magnetic body 316 that is attached to the rotating member 309 and applies a magnetic field to the magnetic sensor 203 of the main body 101 of the image forming apparatus 100. This makes it possible to prolong the product life by allowing the developer to be replenished in a state where there is a margin in the remaining amount of developer accommodated in the developer accommodating chamber downstream in the developer transport direction. Together, it is possible to prevent the deterioration of image quality.

  Further, according to the present embodiment, the stirring blade 315 that is elastically deformable is attached to the outer end surface farthest from the central axis of the rotation shaft portion 307 of the stirring member 308 in parallel with the central axis of the rotation shaft portion 307. In addition, a stirring blade 314 that can be elastically deformed is attached to the outer end surface farthest from the central axis of the rotating shaft portion 305 of the stirring member 306 so as to be parallel to the central axis of the rotating shaft portion 305. Since the developer stuck to the inner bottom surface of each developer accommodating chamber is scraped off by the wings, the developer accommodated in each developer accommodating chamber can be used up completely.

  Further, according to the present embodiment, the developer on the stirring blade 315 is parallel to the central axis of the rotating shaft portion 307 in the vicinity of the boundary surface that connects the developer storage chamber 302b and the developer storage chamber 302c. By attaching the scraper 310 that scrapes G3 and drops it into the developer accommodating chamber 302c, it is possible to prevent the developer on the stirring blade from returning to the upstream developer accommodating chamber, The developer can be conveyed efficiently.

  Further, according to the present embodiment, the stirring blade 314 is formed with the notch 319 that does not hit the edge of the opening 318 of the developer storage chamber 302 b that communicates with the inside of the developer container 301. Thus, the developer can be prevented from returning from the developer storage chamber to the developer container, and the developer can be efficiently conveyed.

  Further, according to the present embodiment, when the weight of the developer G2 accommodated in the developer accommodating chamber 302b is M or less, the magnetic sensor 203 is included in the rotating member 309 when the rotating member 309 falls freely. Since the weight 317 made of metal adjusted to detect the magnetic field of the magnetic body 316 is attached, the weight of the weight is made variable to notify that the remaining amount of the developer G2 is low. Can be adjusted.

  The present invention is not limited to the above-described embodiments in terms of the type, arrangement, number, etc. of the members, and departs from the gist of the invention, such as appropriately replacing the constituent elements with those having the same operational effects. It can change suitably in the range which does not.

  Specifically, in the above embodiment, the remaining amount of the developer G2 in the developer storage chamber 302b is detected in accordance with the distance between the magnetic body 316 and the magnetic sensor 203 that change as the rotating member 309 rotates. Although the case where the magnetic sensor 203 and the magnetic body 316 are used as the set of the detection unit and the detected unit has been described, the present invention is not limited to this, and other sets such as a current sensor and an electrode may be used.

  In the above embodiment, the one-component developer is transported, but a two-component developer may be transported.

  In the above embodiment, the integrated process cartridge including the replenishing roller, the developing roller, and the photosensitive member can be replaced. However, the cartridge not including the replenishing roller, the developing roller, and the photosensitive member may be replaced. .

  In the above embodiment, the stirring member is provided in the developer container. However, the stirring member may not be provided in the developer container.

  The present invention is suitable for a process cartridge mounted on an image forming apparatus that forms an image on a recording material using a developer.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Main body part 102 Process cartridge 201 Support part 202 Substrate 203 Magnetic sensor 300 Container main body 301 Developer container 302 Housing 302a Developer container storage part 302b, 302c Developer storage chamber 303 Container rotation shaft part 304 Container stirring Member 305, 307, 309 Rotating shaft 306, 308 Stirring member 309 Rotating member 310 Scraper 311 Supply roller 312 Developing roller 313 Photoconductor 314, 315 Stirring blade 316 Magnetic body 318 Opening

Claims (1)

An image forming apparatus that forms an image on a recording material using a developer,
A housing for housing the developer, a developer container mounted in the housing and supplying a new developer housed in the housing, and the developer housed in the housing; A developer carrying member that develops an electrostatic latent image by supporting the developer, and the housing contains a first developer containing chamber for containing a developer to be supplied to the developer carrying member, A second developer accommodating chamber for temporarily accommodating a developer supplied from the developer container to the first developer accommodating chamber, and a container accommodating portion for accommodating the developer container; A first rotating shaft portion rotatably installed in one developer accommodating chamber, and a development attached to the first rotating shaft portion and accommodated in the first developer accommodating chamber by the rotation of the first rotating shaft portion. A first agitating member for agitating the developer and a second agitating member rotatably installed in the second developer storage chamber A rotation shaft portion and a second rotation shaft portion are attached to the rotation shaft portion and supplied to the first developer storage chamber while stirring the developer stored in the second developer storage chamber by the rotation of the second rotation shaft portion. a second agitating member which is loosely fitted into the second rotation shaft, the rotation being pressed against the second agitating member, accommodated in the second developer accommodating chamber when exceeding the top dead center a rotating member that free fall to the upper surface of the current image agent, a process cartridge comprising a magnetic member provided on said rotary member,
A magnetic sensor that is provided below the rotating member and outputs an ON signal when the magnetic field strength of the magnetic body is equal to or higher than a predetermined level;
A substrate on which the magnetic sensor is mounted is attached, and a main body that detachably holds the process cartridge;
A control unit for controlling the operation of each unit;
Comprising
The developer container is
A container body containing the new developer therein;
A container rotation shaft portion rotatably supported by the container body;
An in-container stirring member that is attached to the container rotation shaft portion and supplies the second developer storage chamber while stirring the new developer by rotation of the container rotation shaft portion;
Comprising
The controller is
When the length of the ON signal exceeds a predetermined first threshold, the container rotation shaft portion is rotated by a certain amount ,
When the length of the next ON signal after rotating the container rotation shaft part exceeds the first threshold value, the display unit displays a first message indicating that the remaining amount of the developer is low. ,
When the length of the ON signal exceeds a second threshold value that is longer than the first threshold value, the printing operation is stopped and a second message that prompts replacement of the developer container is displayed on the display unit;
Image forming apparatus.

Images