Abstract:
The present invention relates to a developer replenishing mechanism in which a developer replenishing apparatus is provided with a storing container containing a developer therein and capable of discharging the developer therefrom, and detachably attachable to a main body of the developer replenishing apparatus, and a carrying member provided in the storing container for carrying the developer. A control device interrupts the discharging operation of the storing container, and thereafter resumes the discharging operation of the storing container after the storing container is detached with respect to the main body of the developer replenishing apparatus and is again attached thereto, and thereafter inhibits the developing operation of the developing apparatus and interrupts the discharging operation of the storing container when it is detected at the second time by the detecting means that the driving load is not less than the predetermined value.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a developer replenishing mechanism having a developing apparatus for replenishing the developing apparatus with a developer. 
     2. Description of the Related Art 
     A developer replenishing apparatus for replenishing a developing device which is a developing apparatus for effecting the developing process with a developer has a developer bottle which is storing means (a storing container) storing the developer therein, and a carrying portion which is carrying means for carrying the developer supplied from the developer bottle to the developing device, and is designed to replenish the developing device with the stored developer in conformity with the consumption of the developer in the developing device resulting from the image forming operation. 
     The developer bottle is detachably attachable from the carrying portion, and it is possible to continue to replenish the developing device with the developer by detaching the developer bottle in which the developer has been consumed and attaching a new developer bottle. 
     Also, the supply of the developer from the developer bottle to the carrying portion is effected by rotating a supplying screw which is a developer carrying member provided in the developer bottle by driving means such as a motor to thereby discharge the developer from the developer bottle. 
     The driving means may have an abnormality such as an abnormal load monitored by abnormality detecting means which is load detecting means, and when an abnormal load or the like occurs, driving is stopped to thereby prevent the destruction of the driving means. 
     In such a developer replenishing apparatus, however, it is known that the inclination or solidification of the developer in the developer bottle occurs depending on a method of preserving the developer bottle, and when the inclination or solidification occurs, the rotational load of the supplying screw may increase and may sometimes exceed the amount of drivable load of the driving means. 
     In such cases, the abnormality detecting means detects abnormality and the driving by the driving means is stopped, whereby the problem of the destruction of the driving means is solved, but by the detection of this abnormality, an image forming apparatus assumes an operation-inhibited state (an operation-interrupted state), and for the user of the image forming apparatus, this has led to a remarkable reduction in work efficiency. 
     On the other hand, it is also known that the inclination or solidification of the developer as described above can be eliminated in most cases by once detaching the developer bottle from the carrying portion, and shaking the developer bottle, and thereafter attaching it again. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a developer replenishing mechanism in which when the inclination or solidification of a developer in a storing container occurs, the damage of the driving portion of a developer carrying member in the storing container is prevented. 
     It is another object of the present invention to provide a developer replenishing mechanism in which the time during which the developing operation of a developing apparatus is interrupted is shortened to thereby prevent any reduction in a user&#39;s work efficiency. 
     Other objects and features of the present invention will become more fully apparent from the following detailed description when read with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view schematically showing the construction of a printer which is an image forming apparatus according to a first embodiment of the present invention. 
     FIG. 2 is a block diagram schematically showing the construction of control means provided in the image forming apparatus shown in FIG.  1 . 
     FIG. 3 is a typical cross-sectional view schematically showing the constructions of a developing apparatus and a developer replenishing apparatus provided in the image forming apparatus shown in FIG.  1 . 
     FIG. 4 is a typical cross-sectional view of the developing apparatus and the developer replenishing apparatus shown in FIG. 3 as they are seen from their sides. 
     FIG. 5 is a flow chart for illustrating the control of a developing apparatus, carrying means and storing means, of the control of control means in a second embodiment of the present invention. 
     FIG. 6 is a flow chart illustrating the substance of a subroutine for detecting the attachment/detachment of a bottle at S 501  shown in FIG.  5 . 
     FIG. 7 is a flow chart illustrating the detailed substance of a subroutine for replenishing a developing device with a developer at S 502  shown in FIG.  5 . 
     FIG. 8 is a flow chart illustrating the detailed substance of a subroutine for replenishing the developer from a bottle at S 503  shown in FIG.  5 . 
     FIG. 9 is a typical block diagram schematically showing the construction of control means in the second embodiment of the present invention. 
     FIG. 10 is a flow chart for illustrating the control of a developing apparatus, carrying means, storing means and displaying means in the control means shown in FIG.  9 . 
     FIG. 11 is a flow chart for illustrating the detailed substance of a display control routine S 504  shown in FIG.  9 . 
     FIG. 12 shows an example of the display by displaying means for displaying an image formation inhibiting condition. 
     FIG. 13 shows an example of the display by displaying means for displaying a normal condition. 
     FIG. 14 shows an example of the display by displaying means for displaying an abnormal condition. 
     FIG. 15 shows an example of the display by displaying means for displaying the inhibited condition of the replenishment of the developer supply from the bottle. 
     FIG. 16 shows an example of the display by displaying means for displaying the inhibited condition of the replenishment of the developer supply from the bottle. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will hereinafter be described with reference to the accompanying drawings. 
     (First Embodiment) 
     A first embodiment of the present invention will first be described. 
     A printer  1  which is an example suitably showing an image forming apparatus making the most of a developer replenishing mechanism in the present invention will hereinafter be described with reference to FIG.  1 . FIG. 1 is a cross-sectional view schematically showing the construction of the printer  1 . 
     The printer  1  is an image forming apparatus in a form for effecting the transferring process and the fixing process onto a transferring material P which is a sheet-like recording medium in accordance with the electrophotographic method or the electrostatic recording method or the like, and is divided into a reader portion  2  for reading given image information, and a printer portion  3  for transferring an image conforming to the read image information to the transferring material P, fixing the image on the transferring material P and recording the image. 
     The reader portion  2  in the printer  1  is provided with an original feeding apparatus  5  for feeding originals (not shown) which are image information providing sources one by one to a predetermined position on platen glass  4 , a scanner unit  6  for exposing and scanning the image information of the original resting on the platen glass  4 , and a CCD image sensor (hereinafter abbreviated as CCD)  7  for reading the received light image. 
     The scanner unit  6  provided in the reader portion  2  is supported for movement in a horizontal direction in the plane of the drawing sheet of FIG. 1 and a normal direction in the plane of the drawing sheet of FIG. 1, and is comprised of an exposure lamp  6 A which is a light source and a mirror  6 B, whereby a reflected light image L 1  from the original obtained by the light emission of the exposure lamp  6 A is condensed on the CCD  7  through the intermediary of the mirror  6 B, mirrors  8 ,  9  and a lens  10 . 
     On the other hand, the CCD  7  provided in the reader portion  2  is set so as to read the reflected light image L 1  (analog data) obtained by the exposure of the exposure lamp  6 A, and then convert it into image data (digital data) conforming to the read reflected light image L 1  and output it, whereby the image data outputted from the CCD  7  is subjected to image processing along a pre-incorporated predetermined image processing sequence or the like, and thereafter is outputted to a laser driver  11  provided in the printer portion  3 . 
     On the other hand, the printer portion  3  in the printer  1  is provided with a laser beam emitting portion  12  for modulating and emitting a laser beam L 2  in conformity with the image data processed in the reader portion  2 , by being driven by the laser driver  11 , a photosensitive drum  13  which is a latent image bearing member having an endless outer peripheral surface for bearing an electrostatic latent image, a developing apparatus  14  which is developing means for effecting the developing process, a transferring and separating charger  15  for effecting the transferring process, etc., and a fixing apparatus  16  for effecting the fixing process by supplying heat and imparting pressure. 
     The laser beam emitting portion  12  provided in the printer portion  3  is a unit driven by the laser driver  11  to thereby modulate and emit the laser beam L 2 , thereby exposing the outer peripheral surface of the photosensitive drum  13  to form an electrostatic latent image conforming to the image information given onto the outer peripheral surface of the photosensitive drum  13 , and in the present embodiment, the original placed at the predetermined position on the platen glass  4  by the original feeding apparatus  5  serves as an image information providing source to the laser beam emitting portion  12 . 
     On the other hand, around the photosensitive drum  13  provided in the printer portion  3 , there are disposed a primary charger  19  for distributing on the outer peripheral surface of the photosensitive drum  13  a predetermined potential distribution in advance at predetermined timing to thereby prepare for the exposure from the laser beam emitting portion  12 , the developing device  14 , the transferring and separating charger  15  and a cleaner  20  for removing any residual on the outer peripheral surface of the photosensitive drum  13  after the transferring process by the transferring and separating charger  15 . 
     The transferring and separating charger  15  disposed around the photosensitive drum  13  is a unit making the most, for example, of conventional corona discharge or the like to thereby effect the transferring process onto the transferring material P conveyed from a sheet feeding cassette  21  or  22  detachably attachably supported on the printer  1 , and thereafter separating the transferring material P subjected to the transferring process from the outer peripheral surface of the photosensitive drum  13 . 
     In the printer  1  of the above-described construction, a control sequence or the like is set up so that the process from the formation of the electrostatic latent image conforming to the image information to the fixing of the image onto the transferring material P may be done in the following manner. 
     In the printer  1 , the laser beam L 2  conforming to the image information provided from the original resting at the predetermined position on the platen glass  4  is first modulated and emitted from the laser beam emitting portion  12  by the driving of the laser driver  11 , whereby the outer peripheral surface of the photosensitive drum  13  subjected in advance to the potential distribution setting by the primary charger  19  is exposed, whereby an invisible image, i.e., a so-called electrostatic latent image, conforming to the given image information is formed on the outer peripheral surface of the photosensitive drum  13 . 
     Next, the photosensitive drum  13  on the outer peripheral surface of which the electrostatic latent image has been formed is subjected to the developing process by a developer being imparted thereto from the developing apparatus  14  at predetermined timing, whereby a visible image, i.e., a so-called developer image, conforming to the given image information is formed on the outer peripheral surface of the photosensitive drum  13 , whereafter the developer image is transferred onto the transferring material P conveyed from one of the sheet feeding cassettes  21  and  22 , by the transferring and separating charger  15 . 
     Further, by the supply of heat and the imparting of pressure from the fixing apparatus  16  to the transferring material P to which the developer image has been transferred (hereinafter the developer image transferred to the transferring material P will be referred to as the unfixed image), the unfixed image is melted and fixed on the transferring material P. 
     Consequently, in the printer  1 , (1) when the image forming process onto only one surface of the transferring material p is being executed, the transferring material p subjected to the fixing process on one surface thereof is conveyed to sheet discharging rollers  25  by a flapper  24  provided in the printer  1 , whereby it is discharged out of the printer  1 . On the other hand, (2) when the image forming process onto the both surfaces of the transferring material p is being executed, the transferring material p subjected to the fixing process on only one surface thereof is re-conveyed to the transferring area between the photosensitive drum  13  and the transferring and separating charger  15  by the flapper  24  and the sheet discharging rollers  25  via a re-conveying path Ru. On the other hand, the transferring material P subjected to the fixing process on the both surfaces thereof is conveyed to the sheet discharging rollers  25  by the flapper  24 , whereby it is discharged out of the printer  1 . Also, (3) when the continuous image forming process onto one surface or both surfaces of each of a plurality of transferring materials p is being executed, the transferring materials p subjected to the fixing process on one surface or both surfaces thereof are sorted and discharged to a plurality of bins  27  provided on one side of the printer  1 , by the flapper  24  and a sorter  26 . 
     The developing apparatus  14  and a developer replenishing apparatus  38  provided in the printer  1  for replenishing the developing apparatus  14  with the developer will now be described with reference to FIGS. 3 and 4. 
     A developer replenishing mechanism is provided with the developing apparatus  14  and the developer replenishing apparatus  38 . 
     FIG. 3 is a typical cross-sectional view schematically showing the constructions of the developing apparatus  14  and the developer replenishing apparatus  38 , and FIG. 4 is a typical cross-sectional view of the developing apparatus  14  and the developer replenishing apparatus  38  shown in FIG. 3 as they are seen from the sides thereof. 
     The developing apparatus  14 , as shown in FIG. 3, has a developer containing portion  39  for containing therein the developer replenished from the developer replenishing apparatus  38 , and a cylindrical or column-shaped developing sleeve  40  which is a developer carrying member having an endless outer peripheral surface for carrying the developer thereon. 
     The developer containing portion  39  of the developing apparatus  14  is provided with a sensor  41  which is first developer amount detecting means for detecting the amount of contained developer, and the sensor  41  is set so as to output a signal corresponding to the obtained result of detection to a control portion  23  which is control means. 
     On the other hand, the developing sleeve  40  of the developing apparatus  14  is rotatably journalled to the developer containing portion  39 , and is rotatively driven by a driving mechanism (not shown) provided in the printer  1  during development to thereby carry the developer carried on the outer peripheral surface thereof by an electrostatic force or a magnetic force to the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum  13 . 
     On the other hand, the developer replenishing apparatus  38 , as shown in FIG. 4, is provided with a replenishing container (hereinafter simply referred to as the bottle)  42  which is a storing container capable of discharging the developer, and a carrying device  43  which is a carrying unit for carrying the developer to the developing apparatus  14 . 
     In the bottle  42  provided in the developer replenishing apparatus  38 , as shown in FIG. 4, a shutter  44  for opening and closing a discharge port  42 A for discharging the stored developer downwardly in the plane of the drawing sheet is supported for movement in the left to right direction in the plane of the drawing sheet, and a supplying screw  45  for smoothing the discharge of the developer from the discharge port  42 A is rotatably journalled. 
     Also, the bottle  42  is attachable to the carrying device  43 , whereby as shown in FIG. 4, the bottle  42  is attached to the carrying device  43  while being moved from left to right, whereby the shutter  44  which has so far closed the discharge port  42 A slides from right to left and opens the discharge port  42 A, and the discharge of the developer from the bottle  42  to the carrying device  43  becomes possible. Also, the attachment and detachment of the bottle  42  are detected by an attachment/detachment detecting switch  50 . 
     On the other hand, the carrying device  43  provided in the developer replenishing apparatus  38 , as shown in FIG. 3, carries the developer supplied from the bottle  42  from right to left, and an agitating screw  46  which is agitating means is rotatably journalled to moderately agitate the developer stored in the device, and as shown in FIG. 4, two sensors  48  and  49  which are second developer detecting means for the detection of the amount of developer adopted at different detection levels are provided on the left side as viewed in the plane of the drawing sheet. 
     The agitating screw  46  performs its rotating operation when the developer is supplied from the bottle  42  to the carrying device  43  and from the carrying device  43  to the developer containing portion  39 . 
     A falling screw  47  is also rotated when the developer is supplied from the carrying device  43  to the developer containing portion  39 . 
     As the sensors  48  and  49  provided in the carrying device  43 , in the present embodiment, use is made of detecting elements to which the conventional piezoelectric effect is applied, i.e., piezo sensors which are detecting elements making a response conforming to pressure imparted thereto. 
     In the present embodiment, the installed position of the sensor  48  is set more adjacent to the bottom surface of the carrying device  43  than the installed position of the sensor  49  in order to detect the presence or absence of the developer in the carrying device  43  by the sensor  48  and on the other hand, detect by the sensor  49  whether the amount of developer stored in the carrying device  43  has reached a predetermined amount or greater. 
     Also, the sensors  48  and  49  may sometimes be in a state in which pressure is not imparted thereto when the developer is stationary even if the developer is stored in the carrying device  43 , and the outputs of the sensors  48  and  49  when the developer in the carrying device  43  is being agitated by the agitating screw  46  are detected to thereby detect whether the amount of developer stored in the carrying device  43  has reached the predetermined amount or greater. 
     Consequently, in the present embodiment, the discharge of the developer from the bottle  42  to the carrying device  43  is continued until the result of the detection indicating that the amount of developer stored in the carrying device  43  has reached the predetermined amount or greater is outputted from the sensor  49 . 
     That is, at a time soon after the discharge of the developer from the bottle  42  to the carrying device  43  has been started, as shown in FIG. 4, the developer discharged from the discharge port  42 A is carried from right to left while being agitated by the agitating screw  46  and therefore, pressure is not imparted from the surrounding developer only to the sensor  48 , whereby the result of the detection indicating that the developer is present in the carrying device  43  is only outputted from the sensor  48 . 
     However, by the discharge of the developer from the bottle  42  to the carrying device  43  being done to a certain degree, pressure is imparted from the surrounding developer to the sensor  48  and the sensor  49 , whereby the result of the detection indicating that the amount of developer stored in the carrying device  43  has reached the predetermined amount or greater is outputted from the sensor  49 . 
     Also, even when the developer stored in the carrying device  43  is not uniform due to differences in temperature, humidity, etc., the developer stored in the carrying device  43  is agitated for a predetermined time by the agitating screw  46  after the termination of the replenishment from the bottle  42  so that the developer containing portion  39  can be uniformly replenished with a distribution. 
     A control portion  23  which is control means shown in FIG. 1 will now be described with reference to FIG. 2 which is a typical block diagram schematically showing the construction thereof. 
     The control portion  23  effects all kinds of control of the printer  1 , but in FIG. 2, only the portions concerned with the present invention will be described. The other kinds of control of the printer  1  are carried out with the conventional technique. Accordingly, the latent image formation in the present embodiment is carried out with the conventional technique. 
     In FIG. 2, the reference numeral  28  designates a CPU which effects the control of each portion of the printer  1 . 
     The reference numeral  31  denotes a RAM which is memory means capable of reading and writing for storing the control data of the CPU  28  and an error occurrence flag which will be described later. 
     The reference numeral  32  designates a ROM storing a control program of CPU  28  therein. 
     The reference numeral  33  denotes the input/output interface (I/F) of the CPU  28 , and the exchange of input and output signals is effected through this I/F. 
     The reference numeral  29  designates a driving motor for driving a supplying screw  45  which is a developer carrying member for effecting the discharge of the developer from the bottle  42  which is storing means, and by effecting the ON/OFF thereof, the replenishment of the developer supply is effected from the developer bottle to the carrying device. 
     The reference numeral  30  denotes an excess current detecting circuit which is load detecting means for detecting the abnormality of the load of the driving motor  29  which is a driving portion for the supplying screw  45 , and it inputs an abnormality detection signal to the input/output interface  33  when a current exceeding a predetermined consumption current flows. 
     While in the present embodiment, the excess current detecting circuit  30  is used as the load detecting means (abnormality detecting means), this may be replaced by a method of detecting the rotation of the supplying screw  45  by an encoder or the like, and detecting abnormality when a reduction in the number of rotations or the rise of the irregularity of rotation deviates from a predetermined range. 
     The reference numeral  50  designates an attachment/detachment detecting sensor which is attachment/detachment detecting means for detecting the attached and detached states of the bottle  42  and the carrying device  43 , and specifically, it is comprised of a photosensor, a microswitch or the like. 
     The reference numeral  41  denotes a sensor which is a first developer detecting means installed in the developing apparatus  14  shown in FIGS. 3 and 4. 
     The reference numerals  48  and  49  designate sensors which are second developer detecting means for detecting the presence or absence of the developer in the carrying device  43 . When the developer cannot be detected even if the replenishing operation from the bottle  42  to the carrying device  43  is performed for a predetermined time, it is judged that the developer is absent in the bottle  42 . 
     The reference numeral  35  designates a motor for driving the agitating screw  46 , and the reference numeral  36  denotes a motor for driving the falling screw  47  for effecting the carrying of the developer in the carrying device  43  which is carrying means. 
     While in the present embodiment, the agitating screw  46  and the falling screw  47  are driven by the discrete motors, the driving of the screws can also be realized by adopting a construction in which the driving of the motor for driving the agitating screw is transmitted to the falling screw by a clutch. 
     A method of realizing the control means in the present invention will now be described with reference to FIGS. 5 to  8 . 
     FIG. 5 is a flow chart representing the control of the developing apparatus  14 , the carrying device  43  and the bottle  42 , of the control by the control means in the present invention. 
     First, at S 505 , whether an abnormal condition flag is set is examined, and if the flag is set, control is effected in no way, and if the flag is not set, advance is made to S 501 . 
     Next, at S 501 , attachment/detachment of bottle detection which is a subroutine for detecting the attachment and detachment of the bottle  42  to and from the carrying device  43  is carried out. 
     Next, at S 502 , a routine for replenishing the developing device with the developer which is a subroutine for replenishing the developing apparatus  14  with the developer from the carrying device  43  is carried out. 
     Lastly, at S 503 , a routine for replenishing with the developer from the bottle which is a subroutine for replenishing the carrying device  43  with the developer from the bottle  42  is carried out. 
     After S 503  has been carried out, return is made to S 501 , and the subroutines are successively carried out again from the attachment/detachment of bottle detection. 
     FIG. 6 is a flow chart illustrating the substance of the attachment/detachment of bottle detecting subroutine of S 501  of FIG.  5 . 
     This attachment/detachment of bottle detecting subroutine first examines the ON/OFF of the attachment/detachment detecting sensor  50  at S 601 . When the attachment/detachment detecting sensor  50  detects the absence of the bottle, advance is made to S 602 . 
     At S 602 , a developer bottle absence flag is set, and the subroutine is ended. This developer bottle absence flag is stored in the RAM  31  described in connection with FIG.  2 . 
     On the other hand, when the attachment/detachment detecting sensor  50  detects the presence of the bottle, advance is made to S 603 . 
     At S 603 , the bottle absence flag set at S 602  is read out, and if this flag is set, it means the change from a condition in which the bottle  42  is detached to a condition in which the bottle  42  has been detected as being attached, that is, the bottle absence to bottle presence edge has been detected and therefore, advance is made to S 604 , where the bottle absence flag is cleared, and advance is made to S 605 . 
     On the other hand, if at S 603 , the developer bottle absence flag is not set, it is not the attachment/detachment edge of the developer bottle and therefore, the subroutine is ended. 
     At S 605 , a bottle developer replenishment inhibiting flag is read out, and if this flag is set, advance is made to S 606 , where the bottle developer replenishment inhibiting flag is cleared, and advance is made to S 607 . This bottle developer replenishment inhibiting flag is read out and set at the subroutine of FIG.  8 . 
     The operation of replenishing the carrying device  43  with the developer from the bottle  42  is inhibited as will be described later with reference to FIG. 8 while this bottle developer replenishment inhibiting flag is set. 
     On the other hand, if at S 605 , the bottle developer replenishment inhibiting flag is not set, advance is made to S 607 . 
     At S 607 , an image formation inhibiting flag stored in the RAM  31  is read out, and if this flag is not set, the subroutine is ended. 
     On the other hand, if at S 607 , the image formation inhibiting flag is set, advance is made to S 608 , where the image formation inhibiting flag is cleared, and the subroutine is ended. This image formation inhibiting flag is read out in the subroutine of FIG. 8, and if the flag is set, the image forming operation stops being performed. 
     The detailed description of S 502  of FIG. 5 will now be made with reference to the flow chart of FIG.  7 . 
     First, at S 701 , whether the developing sleeve  40  is being rotated is examined. If the developing sleeve  40  is not being rotated, the developer is not consumed and therefore, the developer is not replenished. Therefore, the developing device developer replenishing routine is ended. 
     On the other hand, if the developing sleeve  40  is being rotated, advance is made to S 702 . 
     At S 702 , the sensor  41  of the developing apparatus  14  is examined, and if the sensor  41  of the developing apparatus  14  has detected the presence of the developer, the operation of replenishing the developing apparatus with the developer from the carrying device  43  is unnecessary and therefore, advance is made to S 703 , where the falling screw  47  is put off, and the subroutine is ended. 
     On the other hand, if at S 702 , the sensor  41  of the developing apparatus  14  has detected the absence of the developer, the operation of replenishing the developing apparatus  14  with the developer from the carrying device  43  is necessary and therefore, advance is made to S 704 . 
     At S 704 , the time for which the sensor  41  of the developing apparatus  14  continuously detects the absence of the developer is measured, and if the sensor  41  of the developing apparatus  14  detects the absence of the developer for a predetermined time, advance is made to S 705 , where the image formation inhibiting flag is set. When the image formation inhibiting flag is set, the image forming operation stops being performed. Therefore, the rotation of the developing sleeve  40  is stopped, and this subroutine comes to put the falling screw  47  off. 
     On the other hand, if at S 704 , it is judged that a predetermined time has not elapsed, advance is made to S 706 , where the falling screw  47  is put on, and the operation of replenishing the developing apparatus  14  with the developer from the carrying device  43  is performed. 
     Thus, in the developing device developer replenishing routine described with reference to FIG. 7, the driving of the falling screw  47  is put on/off in conformity with the detection/non-detection of the developer by the sensor  41  of the developing apparatus  14 , and when the sensor  41  cannot detect the developer even if the falling screw  47  is driven for a predetermined time, the image formation inhibiting flag directed to the inhibition of the image forming operation is set. 
     The detailed description of S 503  shown in FIG. 5 will now be made with reference to the flow chart of FIG.  8 . 
     First, at S 801 , the developer replenishment inhibiting flag stored in the RAM  31  is read out, and if this flag is set, it means a developer replenishment inhibiting condition and therefore, advance is made to S 813 , where the driving of the agitating screw  46  and the supplying screw  45  is put off, and the subroutine is ended. This developer replenishment inhibiting flag is set in the present subroutine, and is cleared at S 606  of the attachment/detachment of bottle detecting subroutine described with reference to FIG.  6 . 
     If at S 801 , the developer replenishment inhibiting flag is not set, it means a developer replenishment permitting condition and therefore, advance is made to S 802 . 
     At S 802 , whether the sensor  49  of the carrying device  43  has detected the developer or not is examined, and if it has detected the developer, it is unnecessary to replenish with the developer and therefore, advance is made to S 813 , where the driving of the agitating screw  46  and the supplying screw  45  is put off, and the subroutine is ended. 
     On the other hand, if at S 802 , the sensor  49  of the carrying device  43  has not detected the developer, advance is made to S 803 . 
     At S 803 , whether the condition in which the developer is not detected has not continued for a predetermined time or longer is examined, and if the predetermined time or longer has elapsed, it is judged that the developer is absent in the bottle  42 , and advance is made to S 805 . 
     At S 805 , the error occurrence flag is cleared, and advance is made to S 806 . 
     At S 806 , the bottle developer replenishment inhibiting flag is set. 
     At S 805 , the error occurrence flag is stored in the RAM  31 , and is a flag for recording that abnormality has occurred to the driving motor  29  for the supplying screw  45 . 
     On the other hand, if at S 803 , the absent state of the developer has not been detected for a predetermined time, advance is made to S 804 . 
     At S 804 , the driving of the agitating screw  46  and the supplying screw  45  is put on, and the carrying device  43  is replenished with the developer from the bottle  42 . Next, advance is made to S 807 . 
     At S 807 , the subroutine is ended if the excess current detecting circuit  30  has not detected an excess current. 
     On the other hand, when at S 807 , the excess current is detected, advance is made to S 808 , where the error occurrence flag stored in the RAM  31  is read out, and advance is made to S 809 . 
     At S 809 , the error occurrence flag read out at S 808  is examined, and if it is already set, it means the second detection of the excess current and therefore, advance is made to S 810 , where an abnormal condition flag is set. Image formation is inhibited while this flag is set. 
     On the other hand, if at S 809 , the error occurrence flag is not set, it means the first excess current detection and therefore, advance is made to S 811 , where the error occurrence flag is set, and advance is made to S 812 . At S 812 , the bottle developer replenishment inhibiting flag is set, and the operation of replenishing the carrying device  43  with the developer from the bottle  42  is inhibited. After S 810  and S 812  have been processed, advance is made to S 813 , where the driving of the agitating screw  46  and the supplying screw  45  is put off, and the replenishing of the carrying device  43  with the developer from the bottle  42  is stopped. 
     As described above, in the bottle developer replenishing subroutine, the ON/OFF of the driving of the agitating screw  46  and the supplying screw  45  is controlled in conformity with the presence or absence of the detection of the developer by the sensor  49  of the carrying device  43 , and if the sensor  49  of the carrying device  43  cannot detect the developer for a predetermined time, it is judged that the developer is absent in the bottle  42 . 
     Further, when during the driving of the supplying screw  45 , the excess current of the driving motor  29  is detected in the supplying screw  45  and when the detection of the excess current is the second detection of the excess current, the image forming operation is inhibited, and when the detection of the excess current is the first detection of the excess current, the bottle developer replenishing operation is inhibited. In this latter case, the image forming operation is possible until the developer supplied into the carrying device  43  becomes null. 
     Also, the bottle developer replenishment inhibiting flag set in the present subroutine, as described with reference to FIG. 6, is not cleared unless the attaching/detaching operation of the bottle  42 , i.e., the operation of detaching the bottle  42  from the carrying device  43  and again setting it, is performed. 
     Further, the error occurrence flag set in the present subroutine is not cleared unless it is judged that the developer has become null in the bottle  42 . This is because when the excess current is detected again before a bottle is used up, it is judged that the cause of the excess current having flowed is not the inclination or solidification of the developer in the bottle  42 , but the abnormality of the driving motor  29  itself driving the supplying screw  45 . 
     (Second Embodiment) 
     A second embodiment of the present invention will now be described. In the second embodiment, members similar in construction to those in the first embodiment are given the same reference numerals and need not be described. 
     A typical block diagram schematically representing the construction of the controlling portion  23  which is control means in the present embodiment will first be described with reference to FIG.  9 . The block in the dotted line of FIG. 9 is similar to that of FIG.  2  and therefore need not be described. 
     In FIG. 9, the reference numeral  100  designates a condition displaying portion which is displaying means, and in the present embodiment, it is realized by the use of an LCD (liquid crystal display). Of course, use may be made of other displaying apparatus such as a CRT (cathode ray tube) display or a plasma display. 
     The control of the developing apparatus  14 , the carrying device  43 , the bottle  42  and the condition displaying portion  100  by the controlling portion  23  in the present embodiment will now be described with reference to FIG.  10 . 
     S 501  to S 503  and S 505  in FIG. 10 are the same as S 501  to S 503  and S 505  in FIG.  5  and therefore need not be described. 
     At S 504 , the display of conditions conforming to the conditions of the image formation inhibiting flag and the bottle developer replenishment inhibiting flag described with reference to FIGS. 5 to  8  is effected in the condition displaying portion  100 . 
     The control procedure of the display of the condition in the condition displaying portion  100  will now be described with reference to a flow chart shown in FIG.  11 . 
     First, at S 101 , the abnormality detecting flag set at S 810  of FIG. 8 is examined, and if it is set, advance is made to S 102 , where the display of an abnormal condition as shown in FIG. 14 is effected, and the subroutine is ended. 
     On the other hand, if at S 101 , the abnormality detecting flag is not set, advance is made to S 103 , where whether the image formation inhibiting flag is set is examined. 
     If at S 103 , the image formation inhibiting flag is set, advance is made to S 104 , where the display of the image formation inhibiting condition as shown in FIG. 12 is effected, and the subroutine is ended. 
     On the other hand, if at S 103 , the image formation inhibiting flag is not set, advance is made to S 105 . 
     At S 105 , whether the bottle developer replenishment inhibiting flag is set is examined, and if it is set, advance is made to S 106 , where the display of the bottle developer replenishment inhibiting condition as shown in FIG. 15 or FIG. 16 is effected. 
     On the other hand, if at S 105 , the bottle developer replenishment inhibiting flag is not set, advance is made to S 107 , where the display of a normal condition as shown in FIG. 13 is effected, and the subroutine is ended. 
     Consequently, according to the present embodiment, there can be provided an image forming apparatus in which when the excess current detecting circuit  30  detects the abnormality of the load of the driving motor  29 , in the case of the first abnormality detection after the interchange of the bottle  42  (after the start of the developer supply replenishment by the bottle), it is not regarded as the occurrence of abnormality, but is regarded as an abnormal condition only when abnormality is again detected after the detachment of the bottle  42  has been effected, whereby replenishment can be restored without stopping the operation of the image forming apparatus in the case of abnormal driving caused by the inclination or solidification of the developer in the bottle  42 , whereby any reduction in the work efficiency of the user of the image forming apparatus can be prevented.