Patent Publication Number: US-11640125-B2

Title: Image forming apparatus for regulating removal of developer storage portion, regulation release method

Description:
INCORPORATION BY REFERENCE 
     This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2020-182422 filed on Oct. 30, 2020, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to an image forming apparatus and a regulation release method that is executed in an image forming apparatus. 
     There is known an image forming apparatus that is configured to regulate removal of a developer storage portion, such as a toner container, from an attachment portion to which the developer storage portion is attached. 
     For example, in the image forming apparatus, in a case where an amount of developer stored in a developing portion that develops an electrostatic latent image by using the developer is equal to or smaller than a predetermined first threshold, the developer is supplied to the developing portion from the developer storage portion attached to the attachment portion. In addition, in a case where the amount of developer stored in the developing portion is equal to or smaller than a second threshold that is smaller than the first threshold, a regulation on the removal of the developer storage portion is released. With this configuration, as compared with a configuration where the developer storage portion can be replaced at an arbitrary timing, it is possible to reduce the remaining amount of developer in the developer storage portion at the time of a replacement of the developer storage portion. 
     SUMMARY 
     An image forming apparatus according to an aspect of the present disclosure includes an attachment portion, a regulation portion, an image forming portion, a supply processing portion, a first release processing portion, an acquisition processing portion, and a second release processing portion. A developer storage portion storing developer is attached to an attachment portion. The regulation portion regulates removal of the developer storage portion attached to the attachment portion from the attachment portion. The image forming portion includes a storage portion storing the developer and forms an image by using the developer stored in the storage portion. The supply processing portion supplies the developer from the developer storage portion attached to the attachment portion to the storage portion when a storage amount of the developer stored in the storage portion is equal to or smaller than a predetermined first threshold. The first release processing portion releases regulation on the removal of the developer storage portion imposed by the regulation portion when the storage amount of the developer stored in the storage portion is equal to or smaller than a second threshold that is smaller than the first threshold. The acquisition processing portion acquires a remaining amount of the developer in the developer storage portion attached to the attachment portion when the storage amount of the developer stored in the storage portion is larger than the second threshold. The second release processing portion releases the regulation on the removal of the developer storage portion imposed by the regulation portion, based on the remaining amount of the developer acquired by the acquisition processing portion. 
     A regulation release method according to another aspect of the present disclosure is executed in an image forming apparatus that includes an attachment portion to which a developer storage portion storing developer is attached, a regulation portion configured to regulate removal of the developer storage portion attached to the attachment portion from the attachment portion, and an image forming portion including a storage portion storing the developer and configured to form an image by using the developer stored in the storage portion, the regulation release method including a supply step, a first release step, an acquisition step, and a second release step. In the supply step, the developer is supplied from the developer storage portion attached to the attachment portion to the storage portion when a storage amount of the developer stored in the storage portion is equal to or smaller than a predetermined first threshold. In the first release step, regulation on the removal of the developer storage portion imposed by the regulation portion is released when the storage amount of the developer stored in the storage portion is equal to or smaller than a second threshold that is smaller than the first threshold. In the acquisition step, a remaining amount of the developer in the developer storage portion attached to the attachment portion is acquired when the storage amount of the developer stored in the storage portion is larger than the second threshold. In the second release step, the regulation on the removal of the developer storage portion imposed by the regulation portion is released based on the remaining amount of the developer acquired in the acquisition step. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description with reference where appropriate to the accompanying drawings. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram showing a system configuration of an image forming apparatus according to an embodiment of the present disclosure. 
         FIG.  2    is a diagram showing an outer appearance of the image forming apparatus according to the embodiment of the present disclosure. 
         FIG.  3    is a diagram showing an internal configuration of the image forming apparatus according to the embodiment of the present disclosure. 
         FIG.  4    is a diagram showing a configuration of an image forming unit in the image forming apparatus according to the embodiment of the present disclosure. 
         FIG.  5    is a diagram showing a configuration of a developing portion in the image forming apparatus according to the embodiment of the present disclosure. 
         FIG.  6    is a diagram showing an outer appearance of the image forming apparatus according to the embodiment of the present disclosure. 
         FIG.  7    is a diagram showing a configuration of a toner supply device in the image forming apparatus according to the embodiment of the present disclosure. 
         FIG.  8    is a flowchart showing an example of a regulation release process that is executed in the image forming apparatus according to the embodiment of the present disclosure. 
         FIG.  9    is a flowchart showing an example of a print control process that is executed in the image forming apparatus according to the embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following describes an embodiment of the present disclosure with reference to the accompanying drawings. It should be noted that the following embodiment is an example of a specific embodiment of the present disclosure and should not limit the technical scope of the present disclosure. 
     [Configuration of Image Forming Apparatus  100 ] 
     First, a configuration of an image forming apparatus  100  according to an embodiment of the present disclosure is described with reference to  FIG.  1    and  FIG.  2   .  FIG.  2    is a perspective diagram showing an outer appearance of the image forming apparatus  100 . It is noted that  FIG.  2    shows the image forming apparatus  100  in a state where an ADF  1  is removed therefrom. 
     For convenience of the explanation, the vertical direction in an installation state where the image forming apparatus  100  is installed in a usable manner (the state shown in  FIG.  2   ) is defined as an up-down direction D 1 . In addition, a front-rear direction D 2  is defined on the supposition that a front right surface of the image forming apparatus  100  shown in  FIG.  2    is a front (front surface). In addition, a left-right direction D 3  is defined with reference to the front of the image forming apparatus  100  in the installation state. 
     The image forming apparatus  100  is a multifunction peripheral having a plurality of functions such as a scan function to read an image of a document sheet, a print function to form an image based on image data, a facsimile function, and a copy function. It is noted that the image forming apparatus  100  may be a printer, a facsimile apparatus, or a copier. 
     As shown in  FIG.  1    and  FIG.  2   , the image forming apparatus  100  includes the ADF (Auto Document Feeder)  1 , an image reading portion  2 , an image forming portion  3 , a sheet feed portion  4 , an operation/display portion  5 , a storage portion  6 , a first control portion  7 , a second control portion  8 , and a housing  9 . 
     The ADF  1  conveys the document sheet that is targeted to be read by the scan function. For example, the ADF  1  includes a document sheet setting portion, a plurality of conveyance rollers, a document sheet pressing member, and a sheet ejecting portion. 
     The image reading portion  2  realizes the scan function. For example, the image reading portion  2  includes a document sheet table, a light source, a plurality of mirrors, an optical lens, and a CCD (Charge Coupled Device). 
     The image forming portion  3  realizes the print function. Specifically, the image forming portion  3  forms an image by an electrophotographic method. For example, the image forming portion  3  forms an image by using developer that includes toner (an example of developer of the present disclosure) and carrier. 
     The sheet feed portion  4  feeds a sheet to the image forming portion  3 . For example, the sheet feed portion  4  includes sheet feed cassettes  4 A (see  FIG.  2   ), a sheet conveyance path, and a plurality of conveyance rollers. 
     The operation/display portion  5  is a user interface of the image forming apparatus  100 . For example, the operation/display portion  5  includes a display portion and an operation portion. The display portion is, for example, a liquid crystal display and displays various types of information in response to control instructions from the first control portion  7 . The operation portion is composed of, for example, operation keys or a touch panel through which various types of information are input to the first control portion  7  in response to user operations. 
     The storage portion  6  is a non-volatile storage device. For example, the storage portion  6  is a storage device such as: a non-volatile memory such as a flash memory or an EEPROM; an SSD (Solid State Drive); or an HDD (Hard Disk Drive). 
     The storage portion  6  stores user information regarding users who can log in the image forming apparatus  100 . The user information includes authentication information that is used to authenticate the users. For example, the authentication information is composed of a user name and a password. 
     The first control portion  7  comprehensively controls the image forming apparatus  100 . As shown in  FIG.  1   , the first control portion  7  includes a CPU  7 A, a ROM  7 B, and a RAM  7 C. The CPU  7 A is a processor that executes various types of calculation processes. The ROM  7 B is a nonvolatile storage device in which various types of information such as control programs for causing the CPU  7 A to execute various processes are preliminarily stored. The RAM  7 C is a volatile storage device that is used as a temporary storage memory (working area) for the various types of processes executed by the CPU  7 A. In the first control portion  7 , the CPU  7 A executes the various types of control programs that are preliminarily stored in the ROM  7 B. This allows the image forming apparatus  100  to be controlled comprehensively by the first control portion  7 . 
     The second control portion  8  controls the image forming portion  3 . For example, the second control portion  8  is composed of electronic circuits such as integrated circuits (ASIC, DSP). 
     The housing  9  stores some components of the image forming apparatus  100 . As shown in  FIG.  2   , the housing  9  is formed approximately in a square pole shape. The sheet feed cassettes  4 A are provided at a lower portion of the housing  9  so as to be inserted and drawn in the front-rear direction D 2 . A front cover  9 A is provided on the front surface of the housing  9 . A lower end part of the front cover  9 A is supported in such a way as to be pivotable around a rotary shaft that is elongated in the left-right direction D 3 , and the front cover  9 A is opened as its upper part pivots forward. On the housing  9 , there is provided a sheet ejecting space  9 B that is opened to the left and the front. A sheet with an image formed thereon by the image forming portion  3  is ejected into the sheet ejecting space  9 B. 
     [Configuration of Image Forming Portion  3 ] 
     Next, a configuration of the image forming portion  3  is described with reference to  FIG.  3    and  FIG.  4   .  FIG.  3    is a cross-sectional diagram showing an internal configuration of the housing  9 .  FIG.  4    is a cross-sectional diagram showing a configuration of an image forming unit  11 . 
     As shown in  FIG.  3   , the image forming portion  3  includes a plurality of image forming units  11  to  14 , a laser scanning unit  15 , an intermediate transfer belt  16 , a secondary transfer roller  17 , a fixing device  18 , a toner supply device  19 , and a temperature sensor  20  (see  FIG.  1   ). 
     The image forming units  11  to  14  are electrophotographic image forming units, the image forming unit  11  corresponding to Y (yellow), the image forming unit  12  corresponding to C (cyan), the image forming unit  13  corresponding to M (magenta), and the image forming unit  14  corresponding to K (black). As shown in  FIG.  3   , the image forming units  11  to  14  are aligned along the left-right direction D 3  of the image forming apparatus  100 , in the order of yellow, cyan, magenta, and black from the left side of the image forming apparatus  100 . 
     As shown in  FIG.  4   , the image forming unit  11  includes a photoconductor drum  21 , a charging roller  22 , a developing portion  23 , a primary transfer roller  24 , and a drum cleaning portion  25 . In addition, the image forming units  12  to  14  have the same configuration as the image forming unit  11 . 
     An electrostatic latent image is formed on a surface of the photoconductor drum  21 . Upon receiving a rotational driving force supplied from a motor (not shown), the photoconductor drum  21  rotates in a rotation direction D 4  as shown in  FIG.  4   . 
     The charging roller  22  electrically charges the surface of the photoconductor drum  21 . Light that is emitted from the laser scanning unit  15  based on the image data, is irradiated on the surface of the photoconductor drum  21  that has been electrically charged by the charging roller  22 . This allows the electrostatic latent image to be formed on the surface of the photoconductor drum  21 . 
     The developing portion  23  develops the electrostatic latent image formed on the surface of the photoconductor drum  21  by using the developer. This allows a toner image to be formed on the surface of the photoconductor drum  21 . 
     The primary transfer roller  24  transfers the toner image that has been formed by the developing portion  23 , from the surface of the photoconductor drum  21  to the intermediate transfer belt  16 . 
     The drum cleaning portion  25  removes the toner remaining on the surface of the photoreceptor drum  21  after the transfer of the toner image by the primary transfer roller  24 . 
     The laser scanning unit  15  emits light based on the image data, toward surfaces of the photoconductor drums  21  of the image forming units  11  to  14 . 
     The intermediate transfer belt  16  is an endless belt member to which the toner images formed on the surfaces of the photoconductor drums  21  of the image forming units  11  to  14  are transferred. The intermediate transfer belt  16  is stretched by a drive roller and a stretch roller with a predetermined tension. The drive roller is rotated in response to a rotational driving force that is supplied from a motor (not shown), and thereby the intermediate transfer belt  16  rotates in a rotation direction D 5  as shown in  FIG.  3   . 
     The secondary transfer roller  17  transfers the toner image that has been transferred onto the surface of the intermediate transfer belt  16 , to the sheet that is fed from the sheet feed portion  4 . 
     The fixing device  18  fixes the toner image that has been transferred to the sheet by the secondary transfer roller  17 , to the sheet. 
     The toner supply device  19  supplies the toner to the developing portions  23  of the image forming units  11  to  14 . 
     The temperature sensor  20  detects the temperature inside the housing  9 . The temperature sensor  20  is disposed at any position inside the housing  9 . For example, the temperature sensor  20  is disposed at a container attachment portion  52  of the toner supply device  19 . It is noted that the temperature sensor  20  may be disposed outside the housing  9  to detect the temperature of the place where the image forming apparatus  100  is installed. 
     [Configuration of Developing Portion  23 ] 
     Next, a configuration of the developing portion  23  is described with reference to  FIG.  4    and  FIG.  5   .  FIG.  5    is a cross-sectional diagram taken along a V-V line and viewed from the direction of arrows shown in  FIG.  4   . 
     As shown in  FIG.  4    and  FIG.  5   , the developing portion  23  includes a housing  31 , a first conveyance member  32 , a second conveyance member  33 , a magnet roller  34 , a developing roller  35 , and a toner sensor  36 . 
     As shown in  FIG.  4   , the housing  31  stores the first conveyance member  32 , the second conveyance member  33 , the magnet roller  34 , and the developing roller  35 . In addition, the housing  31  stores the developer. Specifically, the housing  31  stores the developer in an internal space formed by side walls and a bottom surface  41 . The developing portion  23  develops the electrostatic latent image that has been formed on the surface of the photoconductor drum  21  by using the developer stored in the housing  31 . The housing  31  is an example of a storage portion of the present disclosure. 
     As shown in  FIG.  5   , the housing  31  includes a first conveyance path  42  and a second conveyance path  43  along which the developer including the toner is conveyed. Specifically, as shown in  FIG.  4    and  FIG.  5   , a partition wall  44  is formed on the bottom surface  41  of the housing  31 . The side walls, the bottom surface  41 , and the partition wall  44  of the housing  31  form the first conveyance path  42  and the second conveyance path  43  along which the developer is conveyed in the housing  31 . 
     As shown in  FIG.  5   , the first conveyance member  32  is provided in the first conveyance path  42 . The first conveyance member  32  conveys the developer in a conveyance direction D 6  along the front-rear direction D 2  in the first conveyance path  42 , and electrically charges the toner included in the developer. Specifically, the first conveyance member  32  stirs the developer during the conveyance of the developer to electrically charge the toner included in the developer. For example, the first conveyance member  32  is a screw-shaped member. 
     As shown in  FIG.  5   , the second conveyance member  33  is provided in the second conveyance path  43 . The second conveyance member  33  conveys the developer in a conveyance direction D 7  along the front-rear direction D 2  in the second conveyance path  43 , and electrically charges the toner included in the developer. Specifically, the second conveyance member  33  stirs the developer during the conveyance of the developer to electrically charge the toner included in the developer. For example, the second conveyance member  33  is a screw-shaped member. 
     A first connection portion  45  through which the first conveyance path  42  is connected with the second conveyance path  43 , is provided at a downstream end of the partition wall  44  in the conveyance direction D 6 . On the other hand, a second connection portion  46  through which the first conveyance path  42  is connected with the second conveyance path  43 , is provided at a downstream end of the partition wall  44  in the conveyance direction D 7 . This allows the developer stored in the housing  31  to be circulated and conveyed along the first conveyance path  42  and the second conveyance path  43  by the first conveyance member  32  and the second conveyance member  33 . 
     The magnet roller  34  draws up the developer conveyed by the second conveyance member  33 , from the second conveyance path  43 . In addition, the magnet roller  34  supplies, to the developing roller  35 , the toner included in the developer drawn up from the second conveyance path  43 . The developing roller  35  develops the electrostatic latent image formed on the surface of the photoconductor drum  21 , by using the toner supplied from the magnet roller  34 . 
     It is noted that the development method adopted by the developing portion  23  is not limited to the two-component development method using the developer that includes the toner and the carrier. For example, the development method of the developing portion  23  may be one-component development method that uses only the toner. In addition, the developing portion  23  may not include the magnet roller  34 . 
     An opening portion  47  is provided above the first conveyance path  42 . As shown in  FIG.  4   , the opening portion  47  is provided in an upper surface of the housing  31  that covers the first conveyance path  42  from above. The opening portion  47  is provided facing an upstream end, in the conveyance direction D 6 , of the first conveyance path  42 . The opening portion  47  is used to charge the toner supplied from a toner container  51 , into the first conveyance path  42 , wherein the toner container  51  is described below. Specifically, the toner supplied from the toner container  51  is charged into the first conveyance path  42  through the opening portion  47  at a charging position P 1  (see  FIG.  5   ) of the first conveyance path  42 . The charging position P 1  is a position on the bottom surface  41  facing the opening portion  47 . 
     The toner sensor  36  detects an amount of toner at a detection position P 2  (see  FIG.  5   ) positioned on a more downstream side in the conveyance direction D 6  than the charging position P 1  in the first conveyance path  42 . For example, as shown in  FIG.  4   , the toner sensor  36  is provided at a bottom surface portion of the housing  31 . For example, the toner sensor  36  is a magnetic permeability sensor including an LC oscillation circuit that outputs an electric signal corresponding to a magnetic permeability of the developer stored in the housing  31 . 
     For example, in the image forming apparatus  100 , the amount of toner stored in the housing  31  is obtained by integrating the values detected by the toner sensor  36  during a detection period that is longer than the time required for the first conveyance member  32  to convey the toner from the charging position P 1  to the detection position P 2 . For example, the detection period equals to the time required for the toner conveyed by the first conveyance member  32  to circulate inside the developing portion  23  once. 
     [Configuration of Toner Supply Device  19 ] 
     Next, a configuration of the toner supply device  19  is described with reference to  FIG.  1    to  FIG.  3    and  FIG.  6    to  FIG.  7   .  FIG.  6    is a diagram showing a state where a lock unit  53  is removed from the image forming apparatus  100  shown in  FIG.  2   . In addition,  FIG.  7    is a plan diagram showing a configuration of the toner supply device  19 . 
     The toner supply device  19  includes four toner containers  51  shown in  FIG.  3   , a container attachment portion  52  shown in  FIG.  6   , and the lock unit  53  shown in  FIG.  2   . In addition, as shown in  FIG.  1   , the toner supply device  19  includes a drive portion  54 , a data acquiring portion  55 , and an open/closed sensor  56 . 
     The four toner containers  51  are provided in correspondence with the image forming units  11  to  14 . For example, a toner container  51 A shown in  FIG.  3    corresponds to the image forming unit  11  and stores yellow toner. 
     The four toner containers  51  have the same configuration. Specifically, the toner containers  51  are each formed approximately in the shape of a cylinder elongated along the front-rear direction D 2 . Each toner container  51  includes a conveyance member (not shown) that conveys the toner stored therein along the longitudinal direction thereof, and an IC tag (not shown) that stores specific data regarding the toner container  51 . For example, the specific data includes identification information of the toner container  51 , toner information regarding the type, material, and color of the toner stored in the toner container  51 , and initial storage amount information that indicates an initial storage amount of toner in the toner container  51 . The toner container  51  is an example of a developer storage portion of the present disclosure. 
     Four toner containers  51  are attached to the container attachment portion  52 . As shown in  FIG.  3   , the container attachment portion  52  is provided at an upper part of the housing  9 . In addition, as shown in  FIG.  6   , the container attachment portion  52  is provided in the housing  9  at a position facing a back surface of the front cover  9 A. Four opening portions  61  (see  FIG.  6   ) and four attachment portions  62  (see  FIG.  3   ) are formed in the container attachment portion  52 . 
     The four opening portions  61  are provided in correspondence with the four toner containers  51 . The toner containers  51  are respectively inserted in the opening portions  61 . For example, the toner container  51 A is inserted in an opening portion  61 A shown in  FIG.  6   . 
     The four attachment portions  62  are provided in correspondence with the four opening portions  61 . Each attachment portion  62  forms a storage space for storing a toner container  51  that extends from the corresponding opening portion  61  toward the rear of the image forming apparatus  100 . The toner containers  51  are respectively attached to the attachment portions  62 . For example, the toner container  51 A is attached to an attachment portion  62 A shown in  FIG.  3   . 
     The lock unit  53  is configured to regulate removal of the toner containers  51  attached to the container attachment portion  52 , from the container attachment portion  52 . As shown in  FIG.  2   , the lock unit  53  is mounted to the front of the container attachment portion  52 . The lock unit  53  includes four lock devices  63  that are configured to individually switch between placing and not placing restrictions on opening and closing of the four opening portions  61 . That is, the four lock devices  63  are configured to individually switch between locking and unlocking the four opening portions  61 . 
     The four lock devices  63  have the same configuration. Specifically, as shown in  FIG.  7   , each lock device  63  includes a lock cover  71 , a restriction member  72 , a coil spring  73 , a solenoid  74 , and a link member  75 . The restriction member  72 , the coil spring  73 , the solenoid  74 , and the link member  75  in each lock device  63  are provided on an upper surface of the corresponding attachment portion  62 . Each lock device  63  regulates the removal of a toner container  51  attached to a corresponding attachment portion  62 , from the attachment portion  62 . The lock device  63  is an example of a regulation portion of the present disclosure. 
     The lock cover  71  is provided at each opening portion  61  in such a way as to open and close the opening portion  61 . The lock cover  71  is supported such that its lower end portion is pivotable around a rotary shaft that is elongated in the left-right direction D 3 . That is, the lock cover  71  is opened as its upper part pivots forward, in the same manner as the front cover  9 A. 
     An engaged portion  71 A configured to be engaged with an engaging portion  72 A of the restriction member  72 , is provided at the upper part of the lock cover  71 . As shown in  FIG.  7   , the engaged portion  71 A has a hook shape that protrudes from the back surface of the lock cover  71  and bends to the right. 
     The restriction member  72  includes the engaging portion  72 A configured to be engaged with the engaged portion  71 A of the lock cover  71 . As shown in  FIG.  7   , the engaging portion  72 A has a hook shape that protrudes forward and bends to the left. The restriction member  72  is pivotably provided on the upper surface of each attachment portion  62 . Specifically, the restriction member  72  is pivotably supported by a rotary shaft  72 B that is provided parallel to the up-down direction D 1 , on the upper surface of each attachment portion  62 . 
     The restriction member  72  is configured to be rotated between: a lock position where opening of the lock cover  71  is restricted; and a release position where restriction on opening of the lock cover  71 , namely lock of the lock cover  71 , is released. Here, as shown in  FIG.  7   , the lock position is a position where the engaging portion  72 A is engaged with the engaged portion  71 A of the closed lock cover  71 . In addition, the release position is more inside the lock cover  71  than the lock position, and is a position where the engagement between the engaging portion  72 A and the engaged portion  71 A of the lock cover  71  is released (see a lock device  63 C in  FIG.  7   ). In the lock device  63 , opening of the lock cover  71  is restricted by the restriction member  72 , and thereby attachment/detachment of a toner container  51  to/from the corresponding attachment portion  62  is regulated. 
     The coil spring  73  biases the restriction member  72  toward the lock position. Specifically, as shown in  FIG.  7   , the coil spring  73  is provided on the upper surface of each attachment portion  62  to extend in the left-right direction D 3 . One end of the coil spring  73  in the longitudinal direction thereof is fixed to a left side portion of the restriction member  72 , the other end being fixed to the upper surface of each attachment portion  62 . The coil spring  73  is fixed to the restriction member  72  and the upper surface of each attachment portion  62  in a state of being stretched to be longer than its natural length. Therefore, the restriction member  72  is pulled by the coil spring  73  leftward and biased toward the lock position. 
     As shown in  FIG.  7   , the solenoid  74  is provided more inside the lock cover  71  than the restriction member  72 . The solenoid  74  is driven in response to energization to move the restriction member  72  to the release position. Specifically, the solenoid  74  has what is called a pull-type driven configuration, and has a plunger that is elongated in the front-rear direction D 2 . The plunger is connected to the restriction member  72  via the link member  75  that is elongated in the front-rear direction D 2 . 
     The solenoid  74  drives the plunger rearward in response to a power supply from a power source (not shown) that is started based on a control instruction from the first control portion  7 . This allows the restriction member  72  that is connected to the plunger via the link member  75 , to be moved from the lock position to the release position, releasing the lock of the lock cover  71  (see the lock device  63 C in  FIG.  7   ). 
     The drive portion  54  is provided in each attachment portion  62 . The drive portion  54  generates a rotational driving force that is supplied to the conveyance member of a toner container  51  attached to an attachment portion  62  corresponding to the drive portion  54 . For example, the drive portion  54  is a motor. The rotational driving force generated in the drive portion  54  is supplied to the conveyance member of the toner container  51  attached to the corresponding attachment portion  62  via a power transmission mechanism (not shown). This allows the conveyance member to be rotated so that the toner stored in the toner container  51  is conveyed to a toner outlet (not shown) provided inside the toner container  51 . The toner outlet of the toner container  51  attached to the corresponding attachment portion  62  is connected to a toner supply path (not shown) leading to the opening portion  47  (see  FIG.  4   ) of the developing portion  23 . The toner that is discharged from the toner outlet to the outside of the toner container  51  is supplied to the developing portion  23  via the toner supply path and the opening portion  47 . 
     The data acquiring portion  55  is provided in each attachment portion  62 . The data acquiring portion  55  acquires the specific data from the IC tag of a toner container  51  attached to an attachment portion  62  corresponding to the data acquiring portion  55 . For example, the data acquiring portion  55  receives the specific data from the IC tag by executing short-range wireless communication with the IC tag of the toner container  51  attached to the corresponding attachment portion  62 . 
     The open/closed sensor  56  detects whether the front cover  9 A of the housing  9  is in an open state or a closed state. For example, the open/closed sensor  56  is a reflective optical sensor. 
     [Configuration of First Control Portion  7 ] 
     Next, a configuration of the first control portion  7  is described with reference to  FIG.  1   . 
     As shown in  FIG.  1   , the first control portion  7  includes an authentication processing portion  91 , a supply processing portion  92 , a first release processing portion  93 , an acquisition processing portion  94 , a second release processing portion  95 , a notification processing portion  96 , and a restriction processing portion  97 . 
     Specifically, a regulation release program for causing the CPU  7 A of the first control portion  7  to execute a regulation release process (see a flowchart of  FIG.  8   ) and a print control process (see a flowchart of  FIG.  9   ) that are described below, is preliminarily stored in the ROM  7 B of the first control portion  7 . The CPU  7 A of the first control portion  7  functions as the above-described portions by executing the regulation release program stored in the ROM  7 B. 
     It is noted that the regulation release program may be recorded on a non-transitory computer-readable recording medium such as a CD, a DVD, or a flash memory, and may be read from the recording medium and installed in a storage device such as the storage portion  6 . 
     The following describes an example case where, among the developing portions  23 , the toner containers  51 , the attachment portions  62 , and the lock devices  63  corresponding to the image forming units  11  to  14 , the developing portion  23 A (see  FIG.  4   ), the toner container  51 A (see  FIG.  3   ), the attachment portion  62 A (see  FIG.  3   ), and the lock device  63 A (see  FIG.  2   ) corresponding to the image forming unit  11  are focused. The following description also applies to the toner containers  51 , the attachment portions  62 , and the lock devices  63  that correspond to the image forming units  12  to  14 . 
     The authentication processing portion  91  is configured to authenticate the users of the image forming apparatus  100 . For example, the authentication processing portion  91  authenticates the users of the image forming apparatus  100  by using the authentication information stored in the storage portion  6 . 
     For example, the authentication processing portion  91  displays an authentication screen on the operation/display portion  5  in response to a predetermined call operation performed on the operation/display portion  5 , wherein the authentication screen is used for a predetermined authentication operation. The authentication processing portion  91  receives the authentication operation on the authentication screen. For example, the authentication operation is an operation to input a user name and a password. Thereafter, when the information input from the operation/display portion  5  matches any piece of authentication information stored in the storage portion  6 , the authentication processing portion  91  authenticates the user. That is, the authentication processing portion  91  allows the user to log in the image forming apparatus  100 . 
     It is noted that the authentication processing portion  91  executes a log-out process to log out a currently logged-in user when a predetermined log-out operation has been performed on the operation/display portion  5 , when a predetermined set time has passed, or when another user needs to be logged in. 
     When an amount of toner stored in the housing  31  of the development portion  23 A is equal to or smaller than a predetermined first threshold, the supply processing portion  92  supplies the toner from the toner container  51 A attached to the attachment portion  62 A to the housing  31  of the developing portion  23 A. This allows the amount of toner stored in the housing  31  of the developing portion  23 A to be maintained within a predetermined range that includes the first threshold, until a remaining amount of toner in the toner container  51 A is sufficiently reduced. 
     Specifically, the supply processing portion  92  acquires the amount of toner stored in the housing  31  of the developing portion  23 A by using the toner sensor  36  of the developing portion  23 A. In addition, the supply processing portion  92  supplies the toner from the toner container  51 A attached to the attachment portion  62 A to the housing  31  of the development portion  23 A, by driving the drive portion  54  corresponding to the attachment portion  62 A to rotate the conveyance member inside the toner container  51 A by a predetermined reference amount. 
     For example, during an execution of a print process to form an image on a sheet using the image forming portion  3 , the supply processing portion  92  determines in a predetermined determination cycle whether or not the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than the first threshold. 
     When the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than a second threshold that is smaller than the first threshold, the first release processing portion  93  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. With this configuration, as compared with a configuration where the toner container  51 A can be replaced at an arbitrary timing, it is possible to reduce the remaining amount of toner in the toner container  51 A at the time of a replacement of the toner container  51 A. 
     For example, when the amount of toner stored in the housing  31  of the developing portion  23 A that was acquired last during a print process executed immediately before, is equal to or smaller than the second threshold, the first release processing portion  93  waits for a predetermined specific operation to be performed by the user. For example, the specific operation is an operation to open the front cover  9 A. For example, the first release processing portion  93  detects the opening of the front cover  9 A by using the open/closed sensor  56 . It is noted that the specific operation may be a predetermined operation performed on the operation/display portion  5 . 
     When the specific operation performed by the user is detected, the first release processing portion  93  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. Specifically, the first release processing portion  93  drives the solenoid  74  of the lock device  63 A to move the restriction member  72  of the lock device  63 A from the lock position to the release position, thereby releasing regulation on the removal of the toner container  51 A imposed by the lock device  63 A. 
     It is noted that when the amount of toner stored in the housing  31  of the developing portion  23 A that was acquired last during a print process executed immediately before, is equal to or smaller than the second threshold, the first release processing portion  93  may release regulation on the removal of the toner container  51 A imposed by the lock device  63 A, regardless of whether or not the specific operation is performed. 
     Meanwhile, the toner container  51 A might be replaced when the remaining amount of toner in the toner container  51 A is sufficiently reduced even if the amount of toner stored in the developing portion  23 A is larger than the second threshold. This would also make it possible to reduce the remaining amount of toner in the toner container  51 A at the time of replacement of the toner container  51 A. However, in conventional image forming apparatuses, it is determined based on only the amount of toner stored in the developing portion  23 A whether or not to permit a replacement of the toner container  51 A. This excessively restricts the opportunity for the user to replace the toner container  51 A. 
     On the other hand, as described below, the image forming apparatus  100  according to the embodiment of the present disclosure is configured to reduce the remaining amount of toner in the toner container  51  at the time of replacement and increase the opportunity to replace the toner container  51 . 
     The acquisition processing portion  94  acquires the remaining amount of toner in the toner container  51 A attached to the attachment portion  62 A when the amount of toner stored in the housing  31  of the developing portion  23 A is larger than the second threshold. 
     For example, in the image forming apparatus  100 , each time the print process is executed, an amount of toner consumed in the print process is recorded. For example, the first control portion  7  acquires the amount of toner consumed in the print process based on a printing rate of the image data printed in the print process. In addition, the first control portion  7  stores the acquired consumed amount of toner in a predetermined storage area of the storage portion  6 , together with information of the execution timing of the print process or the like. It is noted that the first control portion  7  may acquire the amount of toner consumed in the print process based on a rotation amount of the conveyance member provided in the toner container  51 A. 
     The acquisition processing portion  94  acquires the remaining amount of toner in the toner container  51 A attached to the attachment portion  62 A based on: the total amount of toner consumed from the use start timing of the toner container  51 A; and the initial storage amount information included in the specific data acquired from the IC tag of the toner container  51 A by the data acquiring portion  55  corresponding to the attachment portion  62 A. 
     The second release processing portion  95  is configured to release regulation on the removal of the toner container  51 A imposed by the lock device  63 A, based on the remaining amount of toner acquired by the acquisition processing portion  94 . 
     For example, the second release processing portion  95  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A when the remaining amount of toner acquired by the acquisition processing portion  94  is equal to or smaller than a predetermined first reference value in a case where the temperature in the image forming apparatus  100  is equal to or higher than a predetermined reference temperature. For example, the temperature in the image forming apparatus  100  is detected by the temperature sensor  20 . In addition, the reference temperature is 10 degrees. In addition, the first reference value is 60 grams. It is noted that the reference temperature may be determined in an arbitrary manner to fall within a range considered to influence the solidification of the toner in the toner container  51 A. 
     In addition, the second release processing portion  95  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A in a case where the temperature in the image forming apparatus  100  is lower than the reference temperature when the remaining amount of toner acquired by the acquisition processing portion  94  is equal to or smaller than a second reference value that is greater than the first reference value. For example, the second reference value is 90 grams. It is noted that the first reference value and the second reference value may be determined in an arbitrary manner. 
     For example, when the remaining amount of toner acquired by the acquisition processing portion  94  is equal to or smaller than the first reference value or the second reference value, the second release processing portion  95  waits for the specific operation to be performed by the user. Subsequently, upon detecting the specific operation performed by the user, the second release processing portion  95  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. 
     It is noted that when the remaining amount of toner acquired by the acquisition processing portion  94  is equal to or smaller than the first reference value or the second reference value, the second release processing portion  95  may release regulation on the removal of the toner container  51 A imposed by the lock device  63 A regardless of whether or not the specific operation is performed. 
     When the second release processing portion  95  releases regulation on the removal of the toner container  51 A in a case where the temperature in the image forming apparatus  100  is equal to or higher than the reference temperature, the notification processing portion  96  notifies the user that a timing to replace the toner container  51 A has come. 
     For example, the notification processing portion  96  displays, on the operation/display portion  5 , a first notification screen that includes a message that a timing to replace the toner container  51 A has come. 
     In addition, when the second release processing portion  95  releases regulation on the removal of the toner container  51 A in a case where the temperature in the image forming apparatus  100  is lower than the reference temperature, the notification processing portion  96  notifies the user that the fluidity of the toner in the toner container  51 A has decreased. 
     For example, the notification processing portion  96  displays, on the operation/display portion  5 , a second notification screen that includes: a message that the fluidity of the toner in the toner container  51 A has decreased; and a message that the decrease of the fluidity of the toner can be improved by shaking the toner container  51 A. 
     When the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than a third threshold that is lower than the second threshold, the restriction processing portion  97  imposes restriction on the operation of the image forming portion  3  and releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. 
     Specifically, when the amount of toner stored in the housing  31  of the developing portion  23 A that is acquired by using the toner sensor  36  of the developing portion  23 A, is equal to or smaller than the third threshold, the restriction processing portion  97  stops a currently executed print process and prohibits the print process from being newly executed. 
     In addition, when the amount of toner stored in the housing  31  of the developing portion  23 A that is acquired by using the toner sensor  36  of the developing portion  23 A, is equal to or smaller than the third threshold, the restriction processing portion  97  waits for the specific operation to be performed by the user. 
     Subsequently, upon detecting the specific operation performed by the user, the restriction processing portion  97  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. 
     It is noted that when the amount of toner stored in the housing  31  of the developing portion  23 A that is acquired by using the toner sensor  36  of the developing portion  23 A, is equal to or smaller than the third threshold, the restriction processing portion  97  may release regulation on the removal of the toner container  51 A imposed by the lock device  63 A regardless of whether or not the specific operation is performed. 
     It is noted that the first control portion  7  may not include the authentication processing portion  91 . In addition, the first control portion  7  may not include the notification processing portion  96 . In addition, the first control portion  7  may not include the first release processing portion  93 . In this case, the restriction processing portion  97  is an example of the first release processing portion of the present disclosure. 
     [Regulation Release Process] 
     In the following, with reference to  FIG.  8   , a description is given of an example of the procedure of a regulation release process executed by the first control portion  7  in the image forming apparatus  100 . Here, steps S 11 , S 12 , . . . represent numbers assigned to the processing procedures (steps) executed by the first control portion  7 . It is noted that the regulation release process is executed when the call operation has been performed. 
     &lt;Step S 11 &gt; 
     First, in step S 11 , the first control portion  7  displays the authentication screen on the operation/display portion  5 . 
     &lt;Step S 12 &gt; 
     In step S 12 , the first control portion  7  determines whether or not the authentication operation has been performed on the authentication screen displayed in step S 11 . 
     Here, upon determining that the authentication operation has been performed (Yes side at S 12 ), the first control portion  7  moves the process to step S 13 . In addition, upon determining that the authentication operation has not been performed (No side at S 12 ), the first control portion  7  waits at step S 12  for the authentication operation to be performed. 
     &lt;Step S 13 &gt; 
     In step S 13 , the first control portion  7  determines whether or not the authentication of the user has succeeded based on the authentication operation. It is noted that the processes of steps S 11  to S 13  are executed by the authentication processing portion  91  of the first control portion  7 . 
     Here, upon determining that the authentication of the user has succeeded (Yes side at S 13 ), the first control portion  7  moves the process to step S 14 . In addition, upon determining that the authentication of the user has not succeeded (No side at S 13 ), the first control portion  7  moves the process to step S 12 . 
     It is noted that the processes of steps S 11  to S 13  may be omitted. In this case, the regulation release process may be executed at a timing when the image forming apparatus  100  is powered on, at a timing when the operation mode of the image forming apparatus  100  is switched from a power saving mode in which lower power is consumed than in a normal mode, to the normal mode, or at a timing when the print process ends. 
     &lt;Step S 14 &gt; 
     In step S 14 , the first control portion  7  determines whether or not the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than the second threshold. 
     For example, the first control portion  7  determines whether or not the amount of toner stored in the housing  31  of the developing portion  23 A that was acquired last during a print process executed immediately before, is equal to or smaller than the second threshold. 
     Here, upon determining that the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than the second threshold (Yes side at S 14 ), the first control portion  7  moves the process to step S 15 . In addition, upon determining that the amount of toner stored in the housing  31  of the developing portion  23 A is not equal to or smaller than the second threshold (No side at S 14 ), the first control portion  7  moves the process to step S 16 . 
     &lt;Step S 15 &gt; 
     In step S 15 , the first control portion  7  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. Here, the processes of steps S 14  and S 15  are an example of a first release step of the present disclosure and is executed by the first release processing portion  93  of the first control portion  7 . 
     For example, the first control portion  7  waits for the specific operation to be performed by the user, and upon detecting the specific operation performed by the user, the first control portion  7  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. 
     &lt;Step S 16 &gt; 
     In step S 16 , the first control portion  7  acquires the remaining amount of toner in the toner container  51 A. Here, the process of step S 16  is an example of an acquisition step of the present disclosure and is executed by the acquisition processing portion  94  of the first control portion  7 . 
     &lt;Step S 17 &gt; 
     In step S 17 , the first control portion  7  determines whether or not the temperature in the image forming apparatus  100  is equal to or higher than the reference temperature. 
     Here, upon determining that the temperature in the image forming apparatus  100  is equal to or higher than the reference temperature (Yes side at S 17 ), the first control portion  7  moves the process to step S 18 . In addition, upon determining that the temperature in the image forming apparatus  100  is not equal to or higher than the reference temperature (No side at S 17 ), the first control portion  7  moves the process to step S 21 . 
     &lt;Step S 18 &gt; 
     In step S 18 , the first control portion  7  determines whether or not the remaining amount of toner acquired in step S 16  is equal to or smaller than the first reference value. 
     Here, upon determining that the remaining amount of toner acquired in step S 16  is equal to or smaller than the first reference value (Yes side at S 18 ), the first control portion  7  moves the process to step S 19 . In addition, upon determining that the remaining amount of toner acquired in step S 16  is not equal to or smaller than the first reference value (No side at S 18 ), the first control portion  7  ends the regulation release process. 
     &lt;Step S 19 &gt; 
     In step S 19 , the first control portion  7  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. Here, the processes of steps S 17 , S 18 , and S 19  are an example of a second release step of the present disclosure and are executed by the second release processing portion  95  of the first control portion  7 . 
     For example, the first control portion  7  waits for the specific operation to be performed by the user, and upon detecting the specific operation performed by the user, the first control portion  7  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. 
     &lt;Step S 20 &gt; 
     In step S 20 , the first control portion  7  notifies the user that a timing to replace the toner container  51 A has come. It is noted that the process of step S 20  is executed by the notification processing portion  96  of the first control portion  7 . 
     For example, the first control portion  7  displays, on the operation/display portion  5 , the first notification screen that includes a message that a timing to replace the toner container  51 A has come. It is noted that the first notification screen may be displayed during a wait for the specific operation. 
     &lt;Step S 21 &gt; 
     In step S 21 , the first control portion  7  determines whether or not the remaining amount of toner acquired in step S 16  is equal to or smaller than the second reference value. 
     Here, upon determining that the remaining amount of toner acquired in step S 16  is equal to or smaller than the second reference value (Yes side at S 21 ), the first control portion  7  moves the process to step S 22 . In addition, upon determining that the remaining amount of toner acquired in step S 16  is not equal to or smaller than the second reference value (No side at S 21 ), the first control portion  7  ends the regulation release process. 
     &lt;Step S 22 &gt; 
     In step S 22 , as in step S 19 , the first control portion  7  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. Here, the processes of steps S 17 , S 21 , and S 22  are an example of a second release step of the present disclosure and are executed by the second release processing portion  95  of the first control portion  7 . 
     &lt;Step S 23 &gt; 
     In step S 23 , the first control portion  7  notifies the user that the fluidity of the toner in the toner container  51 A has decreased. It is noted that the process of step S 23  is executed by the notification processing portion  96  of the first control portion  7 . 
     For example, the first control portion  7  displays, on the operation/display portion  5 , the second notification screen that includes: a message that the fluidity of the toner in the toner container  51 A has decreased; and a message that the decrease of the fluidity of the toner can be improved by shaking the toner container  51 A. It is noted that the second notification screen may be displayed during a wait for the specific operation. 
     [Print Control Process] 
     Next, with reference to  FIG.  9   , a description is given of an example of the procedure of the print control process executed by the first control portion  7  in the image forming apparatus  100 . It is noted that the print control process is executed when an instruction to execute the print process is input. 
     &lt;Step S 31 &gt; 
     First, in step S 31 , the first control portion  7  starts an execution-target print process. 
     &lt;Step S 32 &gt; 
     In step S 32 , the first control portion  7  determines whether or not the execution-target print process has ended. 
     Here, upon determining that the execution-target print process has ended (Yes side at S 32 ), the first control portion  7  ends the print control process. In addition, upon determining that the execution-target print process has not ended (No side at S 32 ), the first control portion  7  moves the process to step S 33 . 
     &lt;Step S 33 &gt; 
     In step S 33 , the first control portion  7  determines whether or not the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than the first threshold. 
     Here, upon determining that the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than the first threshold (Yes side at S 33 ), the first control portion  7  moves the process step S 34 . In addition, upon determining that the amount of toner stored in the housing  31  of the developing portion  23 A is not equal to or smaller than the first threshold (No side at S 33 ), the first control portion  7  moves the process to step S 32 . In this case, the first control portion  7  executes the process of step S 33  in the determination cycle until the print process ends. 
     &lt;Step S 34 &gt; 
     In step S 34 , the first control portion  7  determines whether or not the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than the third threshold. 
     Here, upon determining that the amount of toner stored in the housing  31  of the developing portion  23 A is equal to or smaller than the third threshold (Yes side at S 34 ), the first control portion  7  moves the process step S 36 . In addition, upon determining that the amount of toner stored in the housing  31  of the developing portion  23 A is not equal to or smaller than the third threshold (No side at S 34 ), the first control portion  7  moves the process to step S 35 . 
     &lt;Step S 35 &gt; 
     In step S 35 , the first control portion  7  supplies the toner from the toner container  51 A attached to the attachment portion  62 A to the housing  31  of the development portion  23 A. Here, the processes of steps S 33  and S 35  are an example of a supply step of the present disclosure, and is executed by the supply processing portion  92  of the first control portion  7 . 
     &lt;Step S 36 &gt; 
     In step S 36 , the first control portion  7  stops the print process. 
     &lt;Step S 37 &gt; 
     In step S 37 , the first control portion  7  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. It is noted that the processes of steps S 34 , S 36 , and S 37  are executed by the restriction processing portion  97  of the first control portion  7 . 
     For example, the first control portion  7  waits for the specific operation to be performed by the user, and upon detecting the specific operation performed by the user, the first control portion  7  releases regulation on the removal of the toner container  51 A imposed by the lock device  63 A. 
     &lt;Step S 38 &gt; 
     In step S 38 , the first control portion  7  determines whether or not the toner container  51 A has been replaced. 
     For example, when closing of the front cover  9 A is detected by the open/closed sensor  56  while the toner container  51 A is attached to the attachment portion  62 A, the first control portion  7  determines that the toner container  51 A has been replaced. It is noted that the first control portion  7  may determine whether or not the toner container  51 A is attached to the attachment portion  62 A, based on, for example, success or failure of acquisition of the specific data by the data acquisition portion  55  corresponding to the attachment portion  62 A. It is noted that the first control portion  7  may determine whether or not the toner container  51 A attached to the attachment portion  62 A is a newly replaced one, based on the specific data acquired by the data acquiring portion  55 . 
     Here, upon determining that the toner container  51 A has been replaced (Yes side at S 38 ), the first control portion  7  moves the process step S 39 . In addition, upon determining that the toner container  51 A has not been replaced (No side at S 38 ), the first control portion  7  waits at step S 38  for the toner container  51 A to be replaced. 
     &lt;Step S 39 &gt; 
     In step S 39 , the first control portion  7  regulates removal of the toner container  51 A from the attachment portion  62 A. 
     Specifically, the first control portion  7  stops a power supply to the solenoid  74  of the lock device  63 A so as to move the restriction member  72  of the lock device  63 A from the release position to the lock position. This allows the lock device  63 A to regulate the removal of the toner container  51 A. 
     It is noted that after starting the power supply to the solenoid  74  of the lock device  63 A, the first control portion  7  may stop the power supply to the solenoid  74  after a predetermined time lapses. In this case, the engaged portion  71 A of the lock cover  71  of the lock device  63 A may be engaged with the engaging portion  72 A of the restriction member  72  of the lock device  63 A by snap fitting in response to a closing of the lock cover  71 . In addition, the process of step S 39  may be omitted. 
     &lt;Step S 40 &gt; 
     In step S 40 , the first control portion  7  supplies the toner from the toner container  51 A attached to the attachment portion  62 A to the housing  31  of the development portion  23 A. 
     For example, the first control portion  7  supplies the toner from the toner container  51 A to the housing  31  until the amount of toner stored in the housing  31  of the developing portion  23 A exceeds a predetermined fourth threshold that is greater than the third threshold. 
     &lt;Step S 41 &gt; 
     In step S 41 , the first control portion  7  resumes the execution-target print process that was stopped in step S 36 . 
     As described above, in the image forming apparatus  100 , when the amount of toner stored in the developing portion  23 A exceeds the second threshold, it is determined, based on the remaining amount of toner in the toner container  51 A, whether or not to release regulation on the removal of the toner container  51 A imposed by the lock device  63 A. With this configuration, it is possible to release regulation on the removal of the toner container  51 A imposed by the lock device  63 A when the remaining amount of toner in the toner container  51 A is sufficiently reduced even when the amount of toner stored in the developing portion  23 A is larger than the second threshold. As a result, it is possible to reduce the remaining amount of toner in the toner container  51 A at the time of replacement of the toner container  51 A, and increase the opportunity for the user to replace the toner container  51 A. 
     The present disclosure may be applied to an image forming apparatus that forms an image by another image forming method such as an inkjet method. 
     It is to be understood that the embodiments herein are illustrative and not restrictive, since the scope of the disclosure is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.