Patent Publication Number: US-11392060-B2

Title: Powder transport device and powder using apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2020-055410 filed Mar. 26, 2020. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a powder transport device and a powder using apparatus. 
     2. Related Art 
     In the related art, as a device that transports powder, for example, those described in JP-A-2016-59869 ([0024], [0045], and FIGS. 1 and 2) and JP-A-2000-172076 ([0033] to [0037], [0042] and FIGS. 1 to 10) have been known. 
     JP-A-2016-59869 describes a device including a transport pipe which interconnects a storage unit that stores a powder coating material and a coating unit that performs coating using the powder coating material to transport the powder coating material from the storage unit to the coating unit and an agitation transport member (for example, a member having a spiral blade) which is disposed in the transport pipe to agitate and transport the powder coating material. 
     JP-A-2000-172076 describes a device including a powder pump unit which transports a toner as powder from a toner receiving container to a developing device. 
     JP-A-2000-172076 describes that the powder pump unit has a suction type uniaxial eccentric screw pump, and the screw pump includes a screw-shaped rotor, a double-pitch screw-shaped stator, a holder surrounding the stator and defining a powder transport path, and a motor as a driving unit which is rotatable forward or in reverse. 
     JP-A-2000-172076 further describes that when it is considered that toner replenishment is continuously performed several times within a short time, the screw pump is driven to rotate in reverse immediately after a shutdown thereof after completion of the continuous replenishment. 
     SUMMARY 
     Aspects of non-limiting embodiments of the present disclosure relate to a powder transport device and a powder using apparatus that are capable of preventing powder from blocking or narrowing a transport path in which a spiral first transport member that rotates forward to transport powder is disposed, as compared with a case where the first transport member is not rotated in reverse when both (i) a non-operation time during which the first transport member is not rotated and (ii) detection information on a temperature satisfy a condition. 
     Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above. 
     According to an aspect of the present disclosure, there is provided a powder transport device including a transport unit, a spiral first transport member, and a first driving unit. The transport unit has a transport path. The first transport member is rotatably disposed in the transport path and rotates forward to transport powder. The first driving unit drives the first transport member to rotate. The first driving unit rotates the first transport member in reverse when both (i) a non-operation time during which the first transport member is not rotated and (ii) detection information on a temperature satisfy a condition. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiment(s) of the present disclosure will be described in detail based on the following figures, wherein: 
         FIG. 1  is a schematic view illustrating an image forming apparatus according to a first exemplary embodiment; 
         FIG. 2  is a schematic view illustrating a replenishment device according to the first exemplary embodiment; 
         FIG. 3  is a schematic view illustrating the replenishment device of  FIG. 2  as viewed from the lateral side; 
         FIG. 4  is a flowchart illustrating a control operation for the replenishment device and the like; 
         FIG. 5  is a flowchart illustrating a control operation for the replenishment device and the like when a combined condition is applied; 
         FIG. 6A  is a table illustrating an example of a combined condition used for a reverse rotation operation; 
         FIG. 6B  is a table illustrating another example of the combined condition; 
         FIG. 7  is a schematic view illustrating the replenishment device according to a second exemplary embodiment as viewed from the lateral side; 
         FIG. 8A  is a schematic perspective view illustrating a one-way transmission joint of the replenishment device of  FIG. 7 ; 
         FIG. 8B  is a conceptual diagram illustrating an operation state of each transport member by the one-way transmission joint; and 
         FIG. 9  is a schematic view illustrating a powder coating apparatus according to a third exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments to practice the present disclosure will be described with reference to the accompanying drawings. 
     First Exemplary Embodiment 
       FIGS. 1 and 2  are views illustrating a first exemplary embodiment of the present disclosure.  FIG. 1  illustrates the entire image forming apparatus  1  according to a first exemplary embodiment, and  FIG. 2  illustrates a part of the image forming apparatus  1  (for example, a replenishment device). 
     &lt;Image Forming Apparatus&gt; 
     As illustrated in  FIG. 1 , the image forming apparatus  1  includes a case  10  defining a required external appearance, and is provided with an image forming section  2 , a sheet feeding section  4 , a heating and pressurizing section  5 , a power supply (not illustrated), a controller, and the like in the internal space of the case  10 . 
     The image forming section  2  is a section that forms an image made of a developer which is an example of powder and transfers the image onto a sheet  9  which is an example of a recording medium. When a two-component developer containing, for example, a toner and a carrier is used as the developer, the image made of the developer is a toner image made of the toner which is also a part of powder in the two-component developer. 
     As illustrated in  FIG. 1 , the image forming section  2  according to the first exemplary embodiment includes four image forming devices  20 Y,  20 M,  20 C,  20 K which exclusively form toner images of four colors including yellow (Y), magenta (M), cyan (C), and black (K) respectively and an intermediate transfer device  30  which relays and transports the respective toner images formed by the four image forming devices  20 (Y, M, C, K) to a position at which the toner images are transferred onto the sheet  9 . 
     All the four image forming devices  20 (Y, M, C, K) have substantially the same configuration except that the used developers (that is, toners thereof) have different colors. 
     That is, each of the image forming devices  20 (Y, M, C, K) has a photoconductive drum  21  which is driven to rotate in the direction indicated by the arrow A. In each of the image forming devices  20 (Y, M, C, K), devices are provided such as a charging device  22 , an exposure device  23 , a developing device  24 (Y, M, C, K), and a drum cleaning device  26  around the photoconductive drum  21 . In  FIG. 1 , all reference numerals  21  to  23  and  26  are illustrated only in the image forming device  20 K of black (K), and some of them are illustrated in the image forming devices  20 (Y, M, C) of other colors. 
     The photoconductive drum  21  is an example of an image carrier, and is a photoconductor in the form of a drum having a photoconductive layer serving as an image forming surface and an image carrying surface. The charging device  22  is a device that charges the outer circumferential surface (image forming surface) of the photoconductive drum  21  to a required surface potential. The exposure device  23  is an example of a light irradiation device, and is a device that irradiates the outer circumferential surface of the photoconductive drum  21  with light according to image information to form an electrostatic latent image for a corresponding one of the four colors (Y, M, C, K). The image information is information related to images such as, for example, characters, figures, patterns, and photographs, which are input from the outside. 
     The developing device  24 (Y, M, C, K) is an example of an operating unit that operates so as to use a developer  90  which is an example of powder, and is a device that develops each electrostatic latent image formed on the outer circumferential surface of each photoconductive drum  21  using a developer (toner) of a corresponding one of the four colors (Y, M, C, K) to form a toner image of each color. The drum cleaning device  26  is a device that removes an unnecessary substance adhering to the outer circumferential surface of the photoconductive drum  21  during rotation to clean the outer circumferential surface. 
     In these four image forming devices  20 Y,  20 M,  20 C,  20 K, a charging operation by the charging device  22 , an exposure operation by the exposure device  23 , a developing operation by the developing device  24 (Y, M, C, K), and the like are performed respectively on each photoconductive drum  21  which is rotated in the direction indicated by the arrow A. 
     Thus, toner images of the four colors (Y, M, C, K) are individually formed on respective photoconductive drums  21  of the image forming devices  20 (Y, M, C, K). The toner images of the four colors are transported respectively to respective primary transfer positions to be described later between the respective photoconductive drums  21  and the intermediate transfer device  30  by rotation of the photoconductive drums  21 . Only some of the image forming devices  20 (Y, M, C, K) may operate to form a toner image of a corresponding color. 
     As illustrated in  FIG. 1 , the intermediate transfer device  30  has an intermediate transfer belt  31  which is an example of an image carrier or an intermediate transfer body. In the intermediate transfer device  30 , devices are provided such as a primary transfer device  33 , a secondary transfer device  35 , and a belt cleaning device  36  around the intermediate transfer belt  31 . 
     The intermediate transfer belt  31  is an endless belt having a required width and length, and is configured to carry a toner image on the outer circumferential surface thereof. The intermediate transfer belt  31  is supported by plural support rollers  32   a  to  32   f  disposed on the inner circumferential surface side thereof so as to be kept in a state of rotating (circulating) in the direction indicated by the arrow B to sequentially pass through primary transfer positions facing the respective photoconductive drums  21  of the image forming devices  20 (Y, M, C, K) and then, also pass through a secondary transfer position facing the sheet  9 . 
     The primary transfer device  33  is a device that primarily transfers each toner image formed on the photoconductive drum  21  of each of the image forming devices  20 (Y, M, C, K) onto the outer circumferential surface of the intermediate transfer belt  31  by a primary transfer action such as an electrostatic action. For example, the primary transfer device  33  is configured with a contact type transfer device that uses a primary transfer roller to which a transfer bias is supplied. The secondary transfer device  35  is a device that secondarily transfers the toner image primarily transferred onto the outer circumferential surface of the intermediate transfer belt  31  onto the sheet  9  by a secondary transfer action such as an electrostatic action. For example, the secondary transfer device  35  is configured with a contact type transfer device that accommodates a secondary transfer roller to which a transfer bias is supplied. The belt cleaning device  36  is a device that removes an unnecessary substance adhering to the outer circumferential surface of the intermediate transfer belt  31  during rotation to clean the outer circumferential surface. 
     Next, the sheet feeding section  4  is a section that accommodates and delivers the sheet  9  to be fed to a position at which the transfer of an image is performed in the image forming section  2 . 
     The sheet feeding section  4  according to the first exemplary embodiment is configured to feed the sheet  9  to the secondary transfer position in the intermediate transfer device  30  since the image forming section  2  includes the intermediate transfer device  30 . The sheet feeding section  4  is configured with a sheet feeding device including, for example, an accommodating body  41  in which plural sheets  9  are stacked and accommodated on a loading plate  42  and the like in a required orientation, a delivery device  43  which delivers the sheets  9  accommodated in the accommodating body  41  one by one, and a sheet feeding transport path  44  which transports the sheet  9  delivered from the delivery device  43  to the secondary transfer position. For example, plural accommodating bodies  41  may be provided. 
     The sheet feeding transport path  44  is a sheet transport path that transports the sheet  9  delivered from the sheet feeding section  4  so as to feed the sheet  9  to the secondary transfer position at a required timing. In the sheet feeding transport path  44 , for example, plural transport rollers  45   a  to  45   c  which nip and transport the sheet  9  and plural guide members (not illustrated) which secure a transport space for the sheet  9  and guide the transport of the sheet  9  are provided. 
     The sheet  9  is, for example, a recording medium that may be transported in the case  10  to enable the transfer and fixing of a toner image thereon. 
     In the intermediate transfer device  30 , four color toner images formed on the respective photoconductive drums  21  of the image forming devices  20 (Y, M, C, K) are primarily transferred respectively so as to be sequentially superposed on the outer circumferential surface of the intermediate transfer belt  31  which is rotated in the direction indicated by the arrow B by a primary transfer operation of the primary transfer devices  33  and thereafter, the primarily transferred toner images are transported to the secondary transfer position facing the secondary transfer device  35 . 
     Meanwhile, the sheet feeding section  4  feeds the required sheet  9  as the sheet  9  is delivered by the delivery device  43  at the timing of forming and transporting the toner images in the image forming section  2  and thereafter, is transported to the secondary transfer position by the sheet feeding transport path  44 . 
     Thus, at the secondary transfer position in the intermediate transfer device  30 , the toner images primarily transferred onto and transported by the intermediate transfer belt  31  are secondarily transferred onto one surface of the sheet  9  by a secondary transfer operation of the secondary transfer device  35 . 
     Next, the heating and pressurizing section  5  is a section that heats and pressurizes the toner image transferred onto the sheet  9  in the image forming section  2  to fix the toner image on the sheet  9 . 
     As illustrated in  FIG. 1 , the heating and pressurizing section  5  according to the first exemplary embodiment is configured with a fixing device in which devices such as a heating rotating body  51  and a pressurizing rotating body  52  are disposed in the internal space of a case  50  provided with an introduction port and a discharge port for the sheet  9 . 
     In the heating and pressurizing section  5 , the heating rotating body  51  and the pressurizing rotating body  52  rotate in contact with each other in the rotation axis direction thereof. Further, a region in which the heating rotating body  51  and the pressurizing rotating body  52  come into contact with each other is configured as a fixing processing region (nip portion) FN that passes therethrough the sheet  9  having the transferred toner image in a nipped state and performs processing such as heating and pressurization for fixing the toner image on the sheet  9  at the time of passage. 
     In the heating and pressurizing section  5 , the sheet  9  after completion of secondary transfer is transported by a relay transport path  46  and is introduced into the fixing processing region FN. For example, in the relay transport path  46 , a suction type belt transport device  47  is provided. 
     Thus, in the fixing processing region FN of the heating and pressurizing section  5 , the toner image secondarily transferred onto the sheet  9  is heated and pressurized to be fixed on the sheet  9 . 
     By a basic image forming operation by the image forming apparatus  1  described above, a desired multicolor or monochromatic image is formed on one surface of the sheet  9 . 
     Further, the sheet  9  on which the image has been completely formed is discharged to a discharged sheet accommodating unit (not illustrated) via a discharge transport path  48 . In the discharge transport path  48 , for example, a transport roller, a discharge roller (not illustrated), and plural guide members (not illustrated) that guide the transport of the sheet  9  are provided. 
     &lt;Developer Replenishment Device and Others&gt; 
     Further, in the image forming apparatus  1 , as illustrated in  FIG. 1  or  FIG. 2 , the respective developing devices  24 (Y, M, C, K) of the image forming devices  20 (Y, M, C, K) are replenished with replenishment developers  91 (Y, M, C, K) of a required amount corresponding to the amount of a developer to be consumed, for example, by a developing operation from respective replenishment devices  60 (Y, M, C, K) which are an example of a powder transport device  6 . 
     First, the developing device  24 (Y, M, C, K) is an example of an operating unit that operates so as to use the developer  90  which is an example of powder as described above, and as illustrated in  FIG. 2  or  FIG. 3 , is configured by arranging, within a main body (case)  240  provided with an accommodating portion for the developer  90  or a developing opening, components such as a developing roller  241  which performs developing by holding the developer  90  in the accommodating portion and transporting the developer  90  so as to approach and pass through the photoconductive drum  21  from the developing opening, transport members  242 A and  242 B which agitate and transport the developer  90  in the accommodating portion, and an adjustment member  243  which adjusts the amount (layer thickness) of the developer  90  held by the developing roller  241 . 
     The main body  240  has a long shape in a direction substantially along the axial direction of the photoconductive drum  21 . As illustrated in  FIG. 3 , a developer replenishment portion  245  is provided on one longitudinal end of the main body  240  to protrude from the end. Further, the transport member  242 B extends to and is disposed in the developer replenishment portion  245 , and the developer replenishment portion  245  is provided with a receiving port  246  that receives the replenishment developer  91 . 
     Next, each of the replenishment devices  60 (Y, M, C, K) according to the first exemplary embodiment includes an accommodating unit  61 (Y, M, C, K) which individually accommodates a corresponding one of four color replenishment developers  91 (Y, M, C, K) and a transport unit  62 (Y, M, C, K) which transports the corresponding developer  91 (Y, M, C, K) from the accommodating unit  61 (Y, M, C, K) to the developing device  24 (Y, M, C, K). 
     When the developer  90  used in the developing device  24 (Y, M, C, K) is a two-component developer, the replenishment developer  91  is, for example, only a toner or a toner containing a small amount of carrier. 
     The accommodating unit  61 (Y, M, C, K) includes a developer container  71 (Y, M, C, K) which is an example of a powder container that individually accommodates the developer  91 (Y, M, C, K) and a mounting device  72 (Y, M, C, K) for individually and detachably mounting the developer container  71 (Y, M, C, K). 
     The developer container  71 (Y, M, C, K) is a replaceable cartridge type container. Further, the developer container  71  includes a cylindrical container main body provided with a developer discharge port  71   a , a second transport member  73  is disposed within the container main body to transport the developer toward the discharge port  71   a  by rotation thereof, and a driven-side transmission joint  74  is provided on one end of the container main body to transmit a rotational force received from the outside to the second transport member  73 . 
     The discharge port  71   a  is opened and closed by an opening and closing shutter (not illustrated) which is moved in conjunction with an attachment and detachment operation of the developer container  71 . The second transport member  73  is, for example, a member that is entirely formed in a spiral shape and has one end formed as a rotating shaft portion  73   a , that is, a so-called agitator. The transmission joint  74  is a shaft coupling (coupling) which may be coupled to and separated from a driving-side transmission joint, and protrudes from the end of the container body. 
     The mounting device  72 (Y, M, C, K) includes a container holding part  75  which detachably holds a lower portion or front and rear ends of the developer container  71 (Y, M, C, K), a driving-side transmission joint  76  which is coupled to the transmission joint  74  on the developer container  71 (Y, M, C, K) to transmit the rotational force, a developer receiving part  77  which faces the discharge port  71   a  of the developer container  71  held by the container holding part  75  to receive the replenishment developer  91  discharged therefrom, and a second driving device  78  which is an example of a second driving unit that drives the second transport member  73  to rotate via the driving-side transmission joint  76 . 
     The driving-side transmission joint  76  is a shaft coupling (coupling) which may be coupled to and separated from the driven-side transmission joint  74 , and is provided on an end holding portion of the container holding part  75  that holds a back side end of the developer container  71  at the time of mounting of the developer container  71 . 
     The developer receiving part  77  is a part that faces the discharge port  71   a  of the developer container  71  and serves to temporarily receive and store the replenishment developer  91  and also to transmit the developer  91  to the transport unit  62  (that is, a first transport member  65  thereof to be described later). 
     The second driving device  78  includes a motor, a gear train mechanism, and the like. 
     The transport unit  62 (Y, M, C, K) includes a transport pipe  63  having one end connected to the developer receiving part  77  of the mounting device  72 (Y, M, C, K), a connection pipe  64  which interconnects the other end of the transport pipe  63  and a receiving port  246  of the developer replenishment portion  245  of the developing device  24 , the first transport member  65  which rotates forward in a transport portion of the transport pipe  63  to transport the replenishment developer  91 , and a first driving device  66  which is an example of a first driving unit that drives the first transport member  65  to rotate. 
     The transport pipe  63  is an example of a transport unit having a transport path. The transport pipe  63  is, for example, a cylindrical pipe, and the inside thereof defines a tubular transport path  63   a . Further, the transport pipe  63  is provided in one end thereof with a connection port  63   b  connected to the developer receiving part  77  and provided in the other end thereof with a discharge port  63   c  from which the replenishment developer  91  is discharged to drop to the connection pipe  64 . 
     The connection pipe  64  is constituted as a cylindrical hollow pipe having no transport member disposed therein, and is, for example, configured to drop and transport the replenishment developer  91  toward the receiving port  246  of the developer replenishment portion  245 . 
     As illustrated in  FIG. 3 , the first transport member  65  is a member that includes a rotating shaft  65   a  extending along the transport path  63   a  of the transport pipe  63  and a transport blade  65   b  continuously formed on the outer circumferential surface of the rotating shaft  65   a  so as to be spirally wound thereon, that is, a so-called screw auger. The first transport member  65  transports the replenishment developer  91  in a transport direction M so as to move the replenishment developer  91  toward the discharge port  63   c  of the transport pipe  63 . A transport operation by forward rotation of the first transport member  65  is executed so as to correspond to a required replenishment amount of the replenishment developer  91 . The forward rotation is rotation in one predetermined direction necessary to realize the transport direction M of the first transport member  65 . The first transport member  65  is disposed such that the transport blade  65   b  thereof rotates in a state of being close to the transport path  63   a  of the transport pipe  63 . 
     The first driving device  66  includes a motor, a gear train mechanism, and the like. 
     Further, an operation of the replenishment device  60 (Y, M, C, K) is controlled by a control device  15  as illustrated in  FIG. 2 . 
     The control device  15  performs an arithmetic processing according to a control program and control information (including detection information) related to the control of a developer replenishment operation, for example, to output a control command and the like necessary for a control target, and is configured with a microcomputer and the like. The control device  15  may be configured as being a dedicated device for the control of a developer replenishment operation, or may be configured as a part of a central control device that controls the overall operation of the image forming apparatus  1 . 
     As illustrated in  FIG. 2 , each of concentration sensors  28 (Y, M, C, K) that individually detect the concentration of the respective developers  90 (Y, M, C, K) (for example, the concentration of a toner in a case of a two-component developer) existing in the developing devices  24 (Y, M, C, K) is connected to the control device  15 , and detection information of each sensor is individually input to the control device  15 . 
     Further, the control device  15  is connected with a timer  16  that measures (detects) the time (non-operation time) passed after the last (preceding) replenishment operation of the first transport member  65  of each of the replenishment devices  60 (Y, M, C, K) is completed, a temperature sensor  17  that detects the temperature inside the case  10 , and a humidity sensor  18  that detects the humidity inside the case  10 , so that detection information of each sensor or the timer is input to the control device  15 . 
     Meanwhile, the control device  15  is connected to the first driving device  66  and the second driving device  78  (that is, respective drive controllers thereof) which are control targets, and transmits a control signal necessary for each control target. 
     Then, as illustrated in  FIG. 4 , the replenishment device  60 (Y, M, C, K) is configured such that the first driving device  66  rotates the first transport member  65  in reverse when both (i) the non-operation time during which the first transport member  65  is not rotated and (ii) the detection information on the temperature satisfy a condition. 
     The condition at this time refers to a criterion for determining whether the first transport member  65  needs to be rotated in reverse. At least one condition may be prepared as a condition regarding the non-operation time, and at least one condition may be prepared as a condition regarding the detection information on the temperature. In this case, the condition regarding the non-operation time may be set to, for example, 48 hours or more, and the condition regarding the detection information on the temperature may be set to, for example, 40 degrees (° C.). 
     Further, the amount of a reverse rotation operation at this time is set to any amount within a range in which no problem occurs due to the reverse rotation of the first transport member  65 . The reverse rotation operation may be set, for example, such that reverse rotation by half turn is once. 
     An operation of rotating the first transport member  65  in reverse is executed by configuring the first driving device  66  to enable driving in which the rotation direction thereof is switched so as to rotate the first transport member  65  forward and in reverse. In the first exemplary embodiment, a motor that is able to switch between forward rotation and reverse rotation is adopted as the motor constituting the first driving device  66 . 
     Further, as the above-mentioned condition, for example, as illustrated in  FIG. 6A , plural conditions regarding the non-operation time and plural conditions regarding the detection information on the temperature may be prepared, and conditions of combining these may also be applied. In this case, for example, as illustrated in  FIG. 6A , a condition A may be set to 48 hours and a condition B may be set to 96 hours with regard to the non-operation time, and a condition D may be set to 25° C. and a condition E may be set to 35° C. with regard to the detection information on the temperature. 
     When a combined condition is applied as the above-mentioned condition, plural types of the amount of the reverse rotational operation may also be set. In other words, in this case, the amount of the reverse rotational operation is changed according to how the combined condition is satisfied. 
     Next, an operation of the replenishment device  60 (Y, M, C, K) will be described with reference to  FIG. 4  and the like. 
     First, the control device  15  determines whether detection information of each concentration sensor  28 (Y, M, C, K) satisfies the condition as a criterion for determining that replenishment is required (step S 10 ). When there is information determined to satisfy the replenishment condition, the replenishment of the developer by the corresponding replenishment device  60 (Y, M, C, K) that satisfies the condition is performed. 
     Further, before the replenishment device  60 (Y, M, C, K) starts a replenishment operation of the developer and further a transport operation by forward rotation of the first transport member  65 , it is determined whether detection information of each timer  16 (Y, M, C, K) satisfies the condition regarding the non-operation time (S 11 ), and it is determined whether detection information of the temperature sensor  17  satisfies the condition regarding the temperature (S 12 ). 
     When it is determined in steps S 11  and S 12  that at least one of the non-operation or the detection information on the temperature does not satisfy the condition, an operation in which the first driving device  66  of the corresponding replenishment device  60 (Y, M, C, K) operates to rotate the first transport member  65  forward is executed under the control of the control device  15  (S 16 ). This forward rotation operation is performed until a required operation time that is predetermined so as to correspond to a target replenishment amount has passed (S 17 ). 
     In this case, in the corresponding replenishment device  60 (Y, M, C, K), the spiral first transport member  65  is rotated forward in the transport path  63   a  of the transport pipe  63  of the transport unit  62 (Y, M, C, K). 
     Thus, as illustrated in  FIG. 3 , the replenishment developer  91  is transported to the discharge port  63   c  along the transport direction M upon receiving a transport force by the transport blade  65   b  of the first transport member  65  in the transport path  63   a  of the transport pipe  63  and thereafter, is discharged from the discharge port  63   c  to drop through the inside of the connection pipe  64  as indicated by the broken line arrow N, and is transported to the developer replenishment portion  245  of the corresponding developing device  24 (Y, M, C, K). At this time, the replenishment developer  91  is transported to the developer replenishment portion  245  by the amount substantially corresponding to the amount of the forward rotation operation of the first transport member  65 . 
     As a result, the corresponding developing device  24 (Y, M, C, K) is replenished with a required amount of the replenishment developer  91 . Further, the replenished developer  91  is transported to the accommodating portion of the main body  240  by the transport member  242 B and is mixed and used with the existing developer  90 . 
     Incidentally, the corresponding replenishment device  60 (Y, M, C, K) executes an operation in which the second driving device  78  operates to rotate the second transport member  73  forward under the control of the control device  15 . 
     Thus, the replenishment developer  91  in the corresponding developer container  71 (Y, M, C, K) is transported to the discharge port  71   a  along a transport direction J 1  upon receiving a transport force of the second transport member  73  and thereafter, is discharged from the discharge port  71   a  to drop through the inside of the developer receiving part  77  as indicated by the broken line arrow J 2 , and is transported into the transport path  63   a  through the connection port  63   b  of the transport pipe  63 . As a result, the transport path  63   a  of the transport pipe  63  is replenished with the replenishment developer  91 . 
     Meanwhile, when it is determined in steps S 11  and S 12  that both the non-operation time and the detection information on the temperature satisfy the respective conditions, an operation in which the first driving device  66  of the corresponding replenishment device  60 (Y, M, C, K) operates to rotate the first transport member  65  in reverse is executed under the control of the control device  15  (S 14 ). Further, the reverse rotation operation is performed until a predetermined required number of times is completed (S 15 ). 
     In this case, in the corresponding replenishment device  60 (Y, M, C, K), the spiral first transport member  65  is rotated in reverse by a required number of times in the transport path  63   a  of the transport pipe  63  of the transport unit  62 (Y, M, C, K). 
     Thus, the replenishment developer  91  present in the transport path  63   a  of the transport pipe  63  is moved in a direction different from that at the time of transport by the transport blade  65   b  of the first transport member  65  which is rotated in reverse inside the transport path  63   a.    
     As a result, the replenishment developer  91 , which has continued to stay in the transport path  63   a  of the transport pipe  63  for a relatively long time and under a high temperature environment, thus showing lower fluidity and higher aggregation degree, reaches a loosened state by the reverse rotation of the first transport member  65 . 
     Accordingly, in the replenishment device  60 (Y, M, C, K) and further in the image forming apparatus  1  including the replenishment device  60 (Y, M, C, K), the transport path  63   a  of the transport pipe  63  in which the first transport member  65  is disposed is prevented from being blocked or narrowed by aggregation of the replenishment developer  91 . 
     Thus, in the replenishment device  60 (Y, M, C, K), there is no possibility that the transport path  63   a  of the transport pipe  63  is clogged with the replenishment developer  91 , and the replenishment of the developer  91  is stably performed. Further, in the image forming apparatus  1 , good development or image formation is continuously performed. 
     Meanwhile, in a case where the operation in which the first driving device  66  of the corresponding replenishment device  60 (Y, M, C, K) operates to rotate the first transport member  65  in reverse is not executed when it is determined that both the non-operation time and the detection information on the temperature satisfy the respective conditions, the following problems may occur. 
     That is, when the respective conditions are satisfied, since the first transport member  65  stops and the replenishment developer  91  continues to stay in the transport path  63   a  of the transport pipe  63  for a relatively long time and under a high temperature environment, the replenishment developer  91  shows lower fluidity and higher aggregation degree. Further, the degree of aggregation degree is likely to increase in the transport path  63   a  of the transport pipe  63  since the replenishment developer  91  continues to stay under pressure in gaps of the transport blade  65   b  of the spiral first transport member  65  or between the transport blade  65   b  and the transport path  63   a.    
     Thus, in a case where the first transport member is not rotated in reverse when the respective conditions are satisfied, there is a possibility that the developer  91  may aggregate to block or narrow the transport path  63   a  of the transport pipe  63 . In the worst case, this phenomenon may cause the transport pipe  63  to be completely clogged with the replenishment developer  91 . 
     Further, as illustrated in  FIG. 4 , in the replenishment device  60 (Y, M, C, K), the operation of rotating the first transport member  65  in reverse is performed before the transport operation of the replenishment developer  91  by forward rotation of the first transport member  65  is started. 
     Thus, in the replenishment device  60 (Y, M, C, K), the loosened replenishment developer  91  is transported when the transport operation is started. At this time, when the first transport member  65  starts to rotate forward after rotating in reverse, the replenishment developer  91  immediately after being loosened is transported. As a result, the transport path  63   a  of the transport pipe  63  is prevented from being blocked or narrowed by the replenishment developer  91 , and the corresponding developing device  24 (Y, M, C, K) is replenished with the loosened developer  91 . 
     Finally, since the image forming apparatus  1  includes at least the developing device  24  which is an example of an operating unit and the replenishment device  60  which is an example of a powder transport device, from this viewpoint, the image forming apparatus  1  serves as an example of a powder using apparatus that uses powder. 
     Modification of First Exemplary Embodiment 
     The replenishment device  60 (Y, M, C, K) or the image forming apparatus  1  according to the first exemplary embodiment may include detection information on a humidity as the detection information that is used when determining whether the first transport member  65  needs to be rotated in reverse. 
     In this case, detection information of the humidity sensor  18  may be used as the detection information on the humidity. Further, at least one condition regarding the humidity may be prepared. When there is one condition regarding the humidity, the condition may be set to, for example, 50% RH or more. Furthermore, determination as to whether the detection information of the humidity sensor  18  satisfies one condition regarding the humidity may be performed in step S 13  after the step S 11  of determination as to the non-operation time and the step S 12  of determination as to the temperature as indicated by the two-dot dash line in  FIG. 4 . 
     In a case where the detection information on the humidity is included as described above, since the fluidity or the aggregation degree of the replenishment developer  91  is also affected by the humidity, the transport path  63   a  of the transport pipe  63  is more appropriately prevented from being blocked or narrowed by aggregation of the replenishment developer  91  as compared with a case where the humidify detection information is not included. 
     Further, the replenishment device  60 (Y, M, C, K) or the image forming apparatus  1  according to the first exemplary embodiment may be configured to apply a combined condition as the condition that is used when determining whether the first transport member  65  needs to be rotated in reverse. 
     In this case, a combined condition of the non-operation time and the temperature as illustrated in  FIG. 6A  may be applied as the combined condition. Further, in a case of applying this combined condition, plural types of the amount of the reverse rotation operation may be set. 
     Then, in the case of applying this combined condition, as illustrated in  FIG. 5 , when it is determined in step S 20  that the developer replenishment condition is satisfied, it is determined whether both the non-operation time and the detection information on the temperature satisfy the combined condition (S 21 ). Satisfying the condition at this time means that a combined condition to perform the operation of rotating the first transport member  65  in reverse is satisfied. 
     When neither of the non-operation time and the detection information on the temperature satisfies the combined condition in step S 21 , that is, when a combined condition to not perform the operation of rotating the first transport member  65  in reverse is satisfied, an operation in which the first driving device  66  operates to rotate the first transport member  65  forward is executed until a required time has passed under the control of the control device  15  (S 24  and S 25 ), and an operation of replenishing the replenishment developer  91  is performed. 
     Meanwhile, when both the non-operation time and the detection information on the temperature satisfy the combined condition in step S 21 , an operation in which the first driving device  66  operates to rotate the first transport member  65  in reverse is executed until a required number of times is completed under the control of the control device  15  (S 22  and S 23 ). At this time, the reverse rotation operation is performed once, twice, three times, or five times when the combined condition illustrated in  FIG. 6A  is adopted. 
     Further, when this combined condition is satisfied, the replenishment operation of the developer  91  is performed in succession after the reverse rotation operation is completed (S 24  and S 25 ). 
     In a case of applying the combined condition as described above, the transport path  63   a  of the transport pipe  63  in which the first transport member  65  is disposed is more reliably prevented from being blocked or narrowed by the replenishment developer  91  as compared with a case where the number of times by which the reverse rotation operation of the first transport member  65  is performed does not change. Further, in this case, since the combined condition of the non-operation time and the temperature is applied, the transport path  63   a  of the transport pipe  63  is more appropriately prevented from being blocked or narrowed by the replenishment developer  91  according to the situation (the situation of the image forming apparatus  1  or the situation of each replenishment device  60 ). 
     Further, in the case of applying this combined condition, a combined condition including a condition regarding the humidity may be applied as illustrated in  FIG. 6B . 
     With such a configuration, since a combined condition of the non-operation time, the temperature, and the humidity is applied, the transport path  63   a  of the transport pipe  63  is more appropriately prevented from being blocked or narrowed by the replenishment developer  91  according to the situation (the situation of the image forming apparatus  1  or the situation of each replenishment device  60 ). 
     Further, the replenishment device  60 (Y, M, C, K) or the image forming apparatus  1  according to the first exemplary embodiment may be configured to perform an operation of rotating the first transport member  65  in reverse before a developing operation of the developing device  24 (Y, M, C, K) which operates so as to use the developer  90  and further an image forming operation accompanied by the developing operation are started. 
     In this case, information regarding a request (command) signal for the image forming operation is input to the control device  15 . Further, in this case, when the control device  15  receives the request signal for the image forming operation, the first driving device  66  of the transport unit  62 (Y, M, C, K) of the corresponding replenishment device  60 (Y, M, C, K) operates to rotate the spiral first transport member  65  in reverse by a required number of times in the transport path  63   a  of the transport pipe  63  under the control of the control device  15 . 
     With such a configuration in which the operation of rotating the first transport member  65  in reverse is performed before the developing operation and further the image forming operation are started, the loosened replenishment developer  91  may be transported to the corresponding developing device  24 (Y, M, C, K) when the developing operation by the developing device  24 (Y, M, C, K) which is an example of an operating unit is started, as compared with a case where the reverse rotation operation is not performed before the developing operation and further the image forming operation accompanied by the developing operation are started. 
     Furthermore, the replenishment device  60 (Y, M, C, K) or the image forming apparatus  1  according to the first exemplary embodiment may be configured to rotate the second transport member  73  in reverse in the developer container  71 (Y, M, C, K) in conjunction with the operation of rotating the first transport member  65  in reverse. 
     In this case, the second driving device  78  of the corresponding replenishment device  60 (Y, M, C, K) may operate to rotate the second transport member  73  in reverse by a predetermined amount (number of times) under the control of the control device  15 . 
     Further, with such a configuration, the replenishment developer  91  accommodated in the developer container  71 (Y, M, C, K) is moved and loosened by the reverse rotation of the second transport member  73 , as compared with a case where the second transport member  73  is not rotated in reverse in conjunction with the operation of rotating the first transport member  65  in reverse. Thus, the developer receiving part  77  of the transport unit  62  of the corresponding replenishment device  60 (Y, M, C, K) is replenished with the loosened replenishment developer  91  transported from the developer container  71 (Y, M, C, K). 
     Second Exemplary Embodiment 
       FIG. 7  illustrates the replenishment device  60 (Y, M, C, K) according to a second exemplary embodiment of the present disclosure. 
     The replenishment device  60 (Y, M, C, K) has the same configuration as the replenishment device  60 (Y, M, C, K) ( FIG. 2  or  FIG. 3 ) of the first exemplary embodiment except that the first driving device  66  that drives the first transport member  65  also functions as the second driving device  78  that drives the second transport member  73 . 
     The first driving device  66  according to the second exemplary embodiment is configured to transmit a rotational force thereof to the second transport member  73  via a power transmission mechanism  79 . 
     The power transmission mechanism  79  at this time is capable of switching between a transmission state where the first driving device  66  transmits a rotational force for forward rotation of the first transport member  65  to the second transport member  73  and a non-transmission state where the first driving device  66  does not transmit a rotational force for reverse rotation of the first transport member  65  to the second transport member  73 . The power transmission mechanism  79  capable of switching between the transmission state and the non-transmission state is, for example, a device having a functional unit (for example, a switching gear)  79   c  capable of shifting and switching some transmission gears between a transmission position for engagement with a gear train and a non-transmission position for separation from the gear train. The shifting of the transmission gears by the functional unit  79   c  is performed by a moving unit (not illustrated). 
     In the replenishment device  60 (Y, M, C, K), in a case where it is determined that it is necessary to replenish the replenishment developer  91  and when it is determined that any one piece of detection information does not satisfy a condition and that the first transport member  65  does not need to be rotated in reverse, the corresponding first driving device  66  operates to rotate the first transport member  65  forward under the control of the control device  15 . Thus, in the corresponding replenishment device  60 (Y, M, C, K), the replenishment developer  91  in the transport path  63   a  of the transport pipe  63  is transported by the first transport member  65 , and the corresponding developing device  24 (Y, M, C, K) is replenished with the replenishment developer  91 . 
     Further, at this time, the rotational force with which the corresponding first driving device  66  operates to rotate the first transport member  65  forward is transmitted as power of rotating the second transport member  73  forward in the corresponding developer container  71 (Y, M, C, K) via the power transmission mechanism  79 . Thus, in the corresponding replenishment device  60 (Y, M, C, K), the replenishment developer  91  in the corresponding developer container  71 (Y, M, C, K) is transported by the second transport member  73  and is supplied to the developer receiving part  77  of the replenishment device  60 (Y, M, C, K). 
     Meanwhile, when in a case where the replenishment is necessary, when it is determined that all pieces of detection information satisfy a condition and that the first transport member  65  needs to be rotated in reverse, the corresponding first driving device  66  operates to rotate the first transport member  65  in reverse under the control of the control device  15 . Thus, in the corresponding replenishment device  60 (Y, M, C, K), the replenishment developer  91  is loosened in the transport path  63   a  of the transport pipe  63 . 
     Further, at this time, the rotational force with which the corresponding first driving device  66  operates to rotate the first transport member  65  in reverse is not transmitted to the second transport member  73  in the corresponding developer container  71 (Y, M, C, K) as the functional unit  79   c  of the power transmission mechanism  79  operates to shift some transmission gears to the non-transmission position. 
     After the operation of rotating the first transport member  65  in reverse is completed, the above-described replenishment operation of the developer  91  is equally executed. 
     Accordingly, in the replenishment device  60 (Y, M, C, K), the replenishment developer  91  accommodated in the developer container  71 (Y, M, C, K) is moved and loosened by the reverse rotation of the second transport member  73 , as compared with a case where the second transport member  73  is not rotated in reverse in conjunction with the operation of rotating the first transport member  65  in reverse. Thus, the developer receiving part  77  of the transport unit  62  of the corresponding replenishment device  60 (Y, M, C, K) is replenished with the loosened replenishment developer  91  transported from the developer container  71 (Y, M, C, K). 
     Further, the replenishment device  60 (Y, M, C, K) is simplified by omission of the second driving device  78 , as compared with a case where the first driving device  66  does not also function as the second driving device  78 . 
     Modification of Second Exemplary Embodiment 
     As illustrated in  FIGS. 8A and 8B , the replenishment device  60 (Y, M, C, K) or the image forming apparatus  1  according to the second exemplary embodiment may be configured such that the rotational force output from the first driving device  66  is transmitted via a normal power transmission mechanism  79 B (having no functional unit  79   c ) which is connected to the second transport member  73  via one-way transmission joints  74 B,  76 B that transmit only power for forward rotation, instead of the power transmission mechanism  79  having the functional unit  79   c  that shifts the transmission gears. 
     For example, as illustrated in  FIG. 8A , the one-way transmission joints  74 B and  76 B are, respectively, a driven-side one-way transmission joint  74 B having a contact transmission surface  741  and a separation guide surface  743  and a driving-side one-way transmission joint  76 B having a contact transmission surface  761  that may come into contact with the contact transmission surface  741  and a separation guide surface  763  having a slope shape that is guided in a direction of being separated by coming into contact with the separation guide surface  743 . Further, the one-way transmission joint  74 B is slidable within a required range relative to the rotating shaft portion  73   a  of the second transport member  73 , and is elastically pressed by a pressure member  745  such as a spring against a direction E 1  of approaching the other one-way transmission joint  76 B. 
     In the replenishment device  60 (Y, M, C, K) to which the one-way transmission joints  74 B and  76 B are applied, as illustrated in the left half of  FIG. 8B , at the time of forward rotation driving, a motor  66   m  of the first driving device  66  rotates in a rotation direction Q 1  for forward rotation, and the rotational force in the rotation direction Q 1  is transmitted as the rotational force in a direction S of rotating the first transport member  65  forward via the normal power transmission mechanism  79 B. Further, at this time, the rotational force in the rotation direction Q 1  of the motor  66   m  is also transmitted to the second transport member  73  as the rotational force in the direction S of rotating the second transport member  73  forward via the normal power transmission mechanism  79 B and the one-way transmission joints  74 B and  76 B. 
     At this time, in the one-way transmission joints  74 B and  76 B, as illustrated in  FIG. 8A , since the rotational force in the rotation direction Q 1  of the motor  66   m  is transmitted as the rotational force in the forward rotation direction S from a transmission output shaft  79   d  of the normal power transmission mechanism  79 B to the one-way transmission joint  76 B to rotate the one-way transmission joint  76 B in the corresponding direction S, the contact transmission surface  761  of the one-way transmission joint  76 B is brought into contact with the contact transmission surface  741  of the one-way transmission joint  74 B. 
     As a result, the contact transmission surface  761  is kept in contact with the contact transmission surface  741 . Thus, the rotational force in the forward rotation direction S transmitted to the one-way transmission joint  76 B is transmitted to the second transport member  73  via the one-way transmission joint  74 B. 
     Meanwhile, in the replenishment device  60 (Y, M, C, K), as illustrated in the right half of  FIG. 8B , at the time of reverse rotation driving, the motor  66   m  of the first driving device  66  is rotated in a rotation direction Q 2  for reverse rotation, and the rotational force in the rotation direction Q 2  is transmitted as the rotational force in a direction R of rotating the first transport member  65  in reverse via the normal power transmission mechanism  79 B. 
     However, at this time, the transmission of the rotational force in the rotation direction Q 2  of the motor  66   m  is cut off at the one-way transmission joints  74 B and  76 B and is not transmitted as the rotational force in the direction of rotating the second transport member  73  in reverse. 
     That is, in the one-way transmission joints  74 B and  76 B at this time, as illustrated in  FIG. 8B , since the rotational force in the rotation direction Q 2  of the motor  66   m  is transmitted as the rotational force in the reverse rotation direction R from the transmission output shaft  79   d  of the normal power transmission mechanism  79 B to the one-way transmission joint  76 B to rotate the one-way transmission joint  76 B in the corresponding direction R, the separation guide surface  763  of the one-way transmission joint  76 B is brought into contact with the separation guide surface  743  of the one-way transmission joint  74 B. 
     As a result, the separation guide surface  763  moves in contact with the separation guide surface  743 , so that the one-way transmission joint  74 B is shifted in a separation direction indicated by the arrow E 2  against the pressure force of the pressure member  745 . Thus, the rotational force in the reverse rotation direction R transmitted to the one-way transmission joint  76 B is interrupted so as not to be transmitted to the one-way transmission joint  74 B and thus, is also not transmitted to the second transport member  73 . 
     Third Exemplary Embodiment 
       FIG. 9  illustrates a powder coating apparatus  100  according to a third exemplary embodiment of the present disclosure. 
     The powder coating apparatus  100  includes, for example, an accommodating unit  110  which accommodates a powder coating material  93  which is an example of powder, a coating unit  120  which is an example of an operating unit that coats a target coating object  95  with the powder coating material  93  accommodated in the accommodating unit  110 , a heating unit  150  which heats the powder coating material  93  applied to a target coating surface  95   a  of the target coating object  95 , a transport device  140  which transports the target coating object  95  to pass through the coating unit  120  and the heating unit  150 , and a transport unit  160  which transports the powder coating material  93  in the accommodating unit  110  so as to be replenished to the coating unit  120 . 
     Further, the powder coating apparatus  100  is disposed inside a case  101  (not illustrated) provided with a carry-in port and a carry-out port for the target coating object  95 . 
     The accommodating unit  110  includes a container  112  that accommodates therein the powder coating material  93  and is provided in the bottom surface thereof with a discharge port  112   b  through which the powder coating material  93  is discharged, a connection pipe  113  that interconnects the discharge port  112   b  of the container  112  and the transport unit  160 , and a delivery member  114  that delivers the powder coating material  93  in the container  112  from the discharge port  112   b  by rotation thereof. The container  112  may be fixedly provided, or may be detachably replaceable. 
     The powder coating material  93  is powder having powder particles each including, for example, a core portion containing a thermosetting resin and a thermal curing agent and a resin coating portion over the surface of the core portion. Further, for example, a transparent powder coating material (clear coating material) containing no coloring agent in powder particles or a colored powder coating material containing a coloring agent in powder particles is used as the powder coating material  93 . In addition to this, powder formed of a thermoplastic resin may be used as the powder coating material  93 . 
     The target coating object  95  is a conductive sheet-shaped medium having a sheet shape or a plate shape which includes the target coating surface  95   a  to which the powder coating material  93  may be electrostatically adhered. The target coating object  95  is, for example, a metallic medium such as an aluminum foil, an iron plate or a copper plate, a conductive synthetic resin, or a nonmetallic medium formed of a conductive nonmetal material such as conductive rubber. The target coating surface  95   a  may be subjected in advance to a surface treatment such as a primer treatment, a plating treatment, or an electro-deposition coating. The target coating object  95  is grounded (earthed), for example, at the time of powder coating. Incidentally, the grounding of the target coating object  95  may be occasionally omitted since powder coating is possible when there is a potential difference between the target coating object  95  and a coating roller  122  to be described later. 
     The coating unit  120  is an example of an operating unit that operates so as to use the powder coating material  93  which is an example of powder as described above. The coating unit  120  is configured as a coating device formed by arranging, within a main body (case)  121  provided with an accommodating portion for the powder coating material  93  and an coating opening, components such as the coating roller  122  which applies the powder coating material  93  onto the target coating object  95  by holding the powder coating material  93  in the accommodating portion and transporting the powder coating material  93  so as to approach and pass through the target coating object  95  from the coating opening, transport members  123 A and  123 B which transport the powder coating material  93  in the accommodating portion while agitating the powder coating material  93  with a magnetic carrier for charging (not illustrated), and an adjustment member  124  which adjusts the amount (layer thickness) of the powder coating material  93  and the like held by the coating roller  122 . The powder coating material  93  is not limited to a two-component material in which a magnetic carrier is used in combination with a non-magnetic powder coating material, and may also be a one-component material containing only a powder coating material. 
     The main body  121  has a long shape in a direction substantially along the width direction at the time of the transport of the coating target object  95 . A coating material replenishment portion  126  is provided on one longitudinal end of the main body  121  to protrude from the end. Further, the transport member  123 B extends to and is disposed in the coating material replenishment portion  126 , and the coating material replenishment portion  126  is provided with a receiving port  127  to receive the replenished powder coating material  93 . 
     The coating roller  122  is, for example, a roller body having a magnet roller  122   a  in which predetermined magnetic poles are present at a predetermined interval in the circumferential direction and a conductive sleeve  122   b  disposed concentrically around the magnet roller  122   a  to perform rotation. A bias voltage is supplied from a power supply (not illustrated) when the powder coating material  93  is applied to the conductive sleeve  122   b.    
     The transport device  140  includes, for example, a pair of transport rollers  141 , a transport roller  142 , and a roller driving device (not illustrated). 
     The heating unit  150  is configured by arranging, within a main body (case)  151  provided with a carry-in port and a carry-out port for the target coating object  95 , a component such as a heat source  152  which heats and hardens, in a non-contact manner, a coating layer  93 A of the powder coating material  93  applied to the target coating surface  95   a  of the target coating object  95  in the coating unit  120 . The heat source  152 , for example, a heat source such as a halogen lamp or a ceramic heater or a laser irradiation device that irradiates an infrared laser. In addition, the heating unit  150  may be configured to heat the coating layer  93 A of the powder coating material  93  applied to the target coating surface  95   a  of the target coating object  95  in a contact state using a heating rotating body such as a heating roller or a heating belt. 
     The transport unit  160  also serves as an example of a powder transport device that transports the powder coating material  93  which is an example of powder. 
     The transport unit  160  according to the third exemplary embodiment includes a transport pipe  163  disposed such that one end thereof is connected to the discharge port  112   b  of the container  112  of the accommodating unit  110 , a connection pipe  164  which interconnects the other end of the transport pipe  163  and the receiving port  127  of the coating material replenishment portion  126  of the coating unit  120 , a first transport member  165  which transports the powder coating material  93  by rotating forward in a transport portion of the transport pipe  163 , and a first driving device  166  which is an example of a first driving unit that drives the first transport member  165  to rotate. 
     The transport pipe  163  is an example of a transport unit having a transport path as in the case of the transport pipe  63  according to the first exemplary embodiment and the like. The transport pipe  163  is, for example, a cylindrical pipe, and the inside thereof defines a tubular transport path  163   a . Further, the transport pipe  163  is provided in one end thereof with a connection port  163   b  which is connected to the connection pipe  113  of the accommodating unit  110  and provided in the other end thereof with a discharge port  163   c  from which the powder coating material  93  is discharged to drop to the connection pipe  164 . 
     The connection pipe  164  is constituted as a cylindrical hollow pipe in which no transport member is disposed, and for example, is configured to drop and transport the powder coating material  93  toward the receiving port  127  of the coating material replenishment portion  126  of the coating unit  120 . 
     As illustrated in  FIG. 9 , the first transport member  165  is a member that includes a rotating shaft  165   a  extending along the transport path  163   a  of the transport pipe  163  and a transport blade  165   b  continuously formed on the outer circumferential surface of the rotating shaft  165   a  so as to be spirally wound thereon. 
     The first transport member  165  transports the powder coating material  93  in a transport direction M so as to move the powder coating material  93  toward the discharge port  163   c  of the transport pipe  163 . A transport operation by forward rotation of the first transport member  165  is executed so as to correspond to a required replenishment amount of the powder coating material  93 . The first transport member  165  is disposed such that the transport blade  165   b  thereof rotates in a state of being close to the transport path  163   a  of the transport pipe  163 . 
     The first driving device  166  includes a motor, a gear train mechanism, and the like. 
     Further, in the powder coating apparatus  100 , as illustrated in  FIG. 9 , an operation of the transport unit  160  is controlled by a control device  115 . 
     The control device  115  has substantially the same configuration as the control device  15  according to the first exemplary embodiment and the like. Similarly, the control device  115  is connected with a remaining amount sensor  128  that detects the remaining amount of the powder coating material  93  existing in the main body  121  of the coating unit  120 , a timer  116  that measures (detects) the time (non-operation time) passed after the last (preceding) replenishment operation of the first transport member  165  is completed, a temperature sensor  117  that detects the temperature inside the case  101 , and a humidity sensor  118  that detects the humidity inside the case  101 , so that detection information of each sensor or the timer is input to the control device  115 . 
     Meanwhile, the control device  115  is connected to the first driving device  166  (that is, a drive controller thereof) which is a control target, and transmits a control signal necessary for the control target. 
     Then, the transport unit  160  of the powder coating apparatus  100  is configured in substantially the same manner as the replenishment device  60  according to the first exemplary embodiment such that the first driving device  166  rotates the first transport member  165  in reverse when both (i) a non-operation time during which the first transport member  165  is not rotated and (ii) detection information on a temperature satisfy a condition. 
     As for the condition at this time, substantially the same condition as the above-described condition applied to the replenishment device  60  according to the first exemplary embodiment may be applied. 
     First, coating by the powder coating apparatus  100  is performed as follows. 
     In the powder coating apparatus  100 , the target coating object  95  is transported toward the coating unit  120  in a transport direction indicated by the arrow P by the transport device  140 , and in the coating unit  120 , the powder coating material  93  which has been agitated with the magnetic carrier to be frictionally charged is applied to the target coating surface  95   a  of the target coating object  95 . 
     At this time, in the coating unit  120 , the powder coating material  93  in the main body  121  is held in a grain shape via the magnetic carrier on the coating roller  122  (actually on the conductive sleeve  122   b ) rotating in the direction indicated by the arrow, and is transported so as to pass through a position facing the coating target surface  95   a . At this time, the powder coating material  93   a  adhering to the magnetic carrier on the coating roller  122  is electrostatically transferred and applied to the coating target surface  95   a  by a potential difference generated between the coating roller  122  to which a bias voltage is supplied and the grounded coating target surface  95   a . Thus, the coating layer  93 A having a substantially constant thickness is formed on the target coating surface  95   a.    
     Subsequently, the target coating object  95  having the coating layer  93 A formed thereon is transported so as to pass through the heating unit  150  by the transport device  140 . 
     At this time, in the heating unit  150 , the coating layer  93 A on the target coating surface  95   a  of the target coating object  95  is heated and thermally cured. Thus, the coating layer  93 A is formed into a uniform coating film  94  on the target coating surface  95   a.    
     In this way, the target coating surface  95   a  of the target coating object  95  is coated with the powder coating material  93 . 
     Next, in the powder coating apparatus  100 , since the powder coating material  93  is consumed and is reduced in amount in the coating unit  120  via implementation of the coating operation described above, the powder coating material  93  in the accommodating unit  110  is transported and replenished (supplied) to the coating unit  120  by the transport unit  160 . 
     The replenishment of the powder coating material  93  at this time is performed when detection information of the remaining amount sensor  128  in the coating unit  120  satisfies a condition of requiring replenishment, so that the first driving device  166  of the transport unit  160  operates to rotate the first transport member  165  forward until a required time has passed under the control of the control device  115 . At this time, the powder coating material  93  in the transport path  163   a  of the transport pipe  163  is transported in the transport direction M by the first transport member  165  and thereafter, drops to the connection pipe  164  and is transported into the coating material replenishment portion  126  of the coating unit  120 . 
     Further, at this time, the delivery member  114  of the accommodating unit  110  is also rotated for a predetermined time by a driving device (not illustrated). Thus, the powder coating material  93  in the container  112  is delivered and replenished to the transport pipe  163 . 
     Next, in the transport unit  160  of the powder coating apparatus  100 , before the replenishment operation of the powder coating material  93  and further the transport operation by forward rotation of the first transport member  165  are started, it is determined whether detection information of the timer  116  satisfies a condition regarding the non-operation time, and it is determined whether detection information of the temperature sensor  117  satisfies a condition regarding the temperature. 
     In this case, when it is determined that both the non-operation time and the detection information on the temperature satisfy the respective conditions, an operation in which the first driving device  166  operates to rotate the first transport member  165  in reverse is executed until a predetermined required number of times is completed under the control of the control device  115 . 
     Thus, the powder coating material  93  present in the transport path  163   a  of the transport pipe  163  of the transport unit  160  is moved, for example, in a direction different from that at the time of transport by the transport blade  165   b  of the first transport member  165  which rotates in reverse inside the transport path  163   a.    
     As a result, the powder coating material  93 , which has continued to stay in the transport path  163   a  of the transport pipe  163  for a relatively long time and under a high temperature environment, thus showing lower fluidity and higher aggregation degree, reaches a loosened state by the reverse rotation of the first transport member  165 . 
     Accordingly, in the transport unit  160  and further in the powder coating apparatus  100  including the transport unit  160 , the transport path  163   a  of the transport pipe  163  in which the first transport member  165  is disposed is prevented from being blocked or narrowed by aggregation of the powder coating material  93 . 
     Thus, in the transport unit  160 , there is no possibility that the transport path  163   a  of the transport pipe  163  is clogged with the powder coating material  93 , and the replenishment of the powder coating material  93  is stably performed. Further, in the powder coating apparatus  100 , good coating is continuously performed. 
     Meanwhile, in a case where the operation of rotating the first transport member  165  in reverse is not executed in the transport unit  160  when it is determined that both the non-operation time and the detection information on the temperature satisfy the respective conditions, the following problems may occur in substantially the same manner as the above-described case of the replenishment device  60  according to the first exemplary embodiment. 
     That is, when the respective conditions are satisfied, since the first transport member  165  stops and the powder coating material  93  continues to stay in the transport path  163   a  of the transport pipe  163  for a relatively long time and under a high temperature environment, the powder coating material  93  shows lower fluidity and higher aggregation degree. Further, the degree of aggregation degree is likely to increase in the transport path  163   a  of the transport pipe  163  since the powder coating material  93  continues to stay under pressure in gaps of the transport blade  165   b  of the spiral first transport member  165  or between the transport blade  165   b  and the transport path  163   a.    
     Thus, in a case where the first transport member  165  is not rotated in reverse when the respective conditions are satisfied, there is a possibility that the powder coating material  93  may aggregate to block or narrow the transport path  163   a  of the transport pipe  163 . In the worst case, this phenomenon may cause the transport pipe  163  to be completely clogged with the powder coating material  93 . 
     Further, in the transport unit  160 , the operation of rotating the first transport member  165  in reverse is performed before the transport operation of the powder coating material  93  by forward rotation of the first transport member  165  is started. 
     Thus, in the transport unit  160 , the loosened powder coating material  93  is transported when the transport operation is started. At this time, when the first transport member  165  starts to rotate forward after rotating in reverse, the powder coating material  93  immediately after being loosened is transported. As a result, the transport path  163   a  of the transport pipe  163  is prevented from being blocked or narrowed by the powder coating material  93 , and the loosened powder coating material  93  is transported and replenished to the coating unit  120 . 
     Incidentally, since the powder coating apparatus  100  includes at least the coating unit  120  which is an example of an operating unit and the transport unit  160  which is an example of a powder transport device, from this viewpoint, the powder coating apparatus  100  serves as an example of a powder using apparatus that uses powder. 
     The modification of the first exemplary embodiment described above may be equally applied to the transport unit  160  or the powder coating apparatus  100 . 
     Further, the transport unit  160  or the powder coating apparatus  100  may be configured in the same manner as the case of the replenishment device  60  described in the second exemplary embodiment or the modification thereof when the accommodating unit  110  is configured using a coating material container that is detachably mounted and has a second transport member which transports the powder coating material  93  toward the discharge port  112   b.    
     [Modifications] 
     The present disclosure is not limited to the description of the first to third exemplary embodiments and also includes, for example, modifications as follows. 
     In the replenishment device  60 (Y, M, C, K) or the image forming apparatus  1  according to the first exemplary embodiment, the developer container  71 (Y, M, C, K) of the accommodating unit  61  may be adopted as having information on the date of manufacture, and when the control device  15  determines that detection information on the number of days passed from the date of manufacture of the developer container  71 (Y, M, C, K) satisfies a condition, an operation of rotating the second transport member  73  in reverse after the developer container  71 (Y, M, C, K) is first mounted on each mounting device  72 (Y, M, C, K) may be performed under the control of the control device  15 . 
     With this configuration, aggregation of the replenishment developer  91  that is occurring in a new developer container  71 (Y, M, C, K) before mounting is eliminated. 
     In this case, the developer container  71 (Y, M, C, K) may be provided with a storage such as a non-volatile memory in which necessary information such as the date of manufacture is stored. The date of manufacture may be the date corresponding to the time when the replenishment developer  91  is first provided in each container, but the date of manufacture may be regarded as the time when the replenishment developer  91  is accommodated. 
     Further, in this case, the mounting device  72 (Y, M, C, K) of the replenishment device  60 (Y, M, C, K) may have a reading device  19  which reads information in the storage of the developer container  71 (Y, M, C, K) as illustrated by the two-dot dash line in  FIG. 2  and may be configured to connect the reading device  19  to the control device  15  so as to transmit the read detection information. 
     As for a condition regarding detection information on the number of days that have passed, an appropriate number of days determined from the viewpoint of eliminating a troubled state such as aggregation of the replenishment developer  91  in the developer container  71  is set. 
     Further, the number of times by which the operation of rotating the second transport member  73  in reverse when this condition is satisfied may be fixed, or may vary according to the number of days that have passed. 
     Then, the reverse rotation operation in this configuration may be performed, for example, immediately after the corresponding developer container  71 (Y, M, C, K) is mounted or immediately before a developer replenishment operation that is first performed after the mounting. This configuration may be equally adopted in the powder coating apparatus  100  according to the third exemplary embodiment when the accommodating unit  110  is configured using a coating material container that is detachably mounted and has a second transport member. When the accommodating unit  110  takes the form of a container that is fixedly disposed without using a coating material container that is detachably mounted, a second transport member that rotates forward to transport the powder coating material  93  may be disposed in the container. 
     Further, the replenishment device  60 (Y, M, C, K) or the image forming apparatus  1  according to the first and second exemplary embodiments may be configured such that at least the conditions regarding the non-operation time and the detection information on the temperature are changed and the number of times by which the operation of rotating the first transport member  65  in reverse is performed is changed according to a difference in the detection information on the frequency of use of the image forming apparatus  1 . 
     In this case, the detection information may include detection information such as a humidity. Further, in this case, as for the frequency of use, for example, when the frequency of use is limited to once a week, the conditions regarding the non-operation time and the detection information on the temperature may be changed to a mild condition to increase the number of times by which the reverse rotation operation is performed. For example, a non-use period from the last power-off to the next power-on may be detected as the frequency of use. 
     With this configuration, as compared with a case where this configuration is not adopted, the transport path  63   a  of the transport pipe  63  of the transport unit  62  is appropriately prevented from being blocked or narrowed by the replenishment developer  91 . This configuration may be equally adopted in the powder coating apparatus  100  according to the third exemplary embodiment by detecting the frequency of use of the powder coating apparatus  100 . 
     Further, the first and second exemplary embodiments have described the configuration examples of the image forming apparatus  1  including plural replenishment devices  60 (Y, M, C, K), but the image forming apparatus  1  may include a single replenishment device  60 . In other words, the image forming apparatus is not limited to one that forms a multicolor image using developers of plural colors, but may be one that forms a monochromatic image using a developer of one color. In a case of the latter image forming apparatus that forms a monochromatic image, only one replenishment device that replenishes a developer of one color is sufficient for the replenishment device  60 . 
     Further, the third exemplary embodiment has described the configuration example of the powder coating apparatus  100  including the single coating unit  120 , but the powder coating apparatus  100  may include plural coating units  120 . In this case, the plural coating units  120  are not limited to different types of coating units  120  that use different types of powder coating materials  93 , but may be the same type of coating units  120  that use the same type of powder coating material  93 . 
     Further, the present disclosure may also be applied almost equally to a powder transport device that handles powder other than a developer or a powder coating material as long as the powder transport device includes a transport unit having a transport path, a spiral first transport member that is rotatably disposed in the transport path and rotates forward to transport powder, and a driving unit that drives the first transport member to rotate, and the transport path in which the first transport member is disposed is prevented from being blocked or narrowed by the powder. 
     In this case, examples of the powder other than the developer or the powder coating material may include powder for chemicals, powder for food, or powder for the manufacture of electrodes. Further, the powder transport device may be referred to as a powder supply device when it includes a powder supply source and a powder supply destination. 
     Further, the present disclosure is not limited to the image forming apparatus or the powder coating apparatus illustrated in the first to third exemplary embodiments as long as a powder using apparatus includes an accommodating unit that accommodates powder, an operating unit that operates so as to use the powder in the accommodating unit, and a transport unit that transports the powder in the accommodating unit to the operating unit and at least a part of the transport unit is configured with the powder transport device, and may also be applied almost equally to other powder using apparatuses. 
     In this case, examples of the other powder using apparatuses include a manufacturing apparatus using the powder, a machining apparatus using the powder, and an inspection apparatus using the powder. 
     The foregoing description of the exemplary embodiments of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical applications, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.