result of the selection and the color of toner are displayed iv at step s610 it is decided whether the first bottle sensor 89 was changed to on or not namely the first toner bottle 41 was attached to the first developing device 5 if it was attached the first developing device 5 is automatically selected irrespective to the operation of the first selecting key 124 if it was selected from the first the selection is unchanged at step s611 the first indicating led 126 is turned on while the second indicating led 127 is turned off to indicate that the first one is selected then the subroutine for displaying the color of toner is called and executed at step s612 at step s613 the first replenishing motor 60 is started to drive and toner in the first toner bottle is begun to feed into the first developing device under the cooperation of the first replenishing motor with the transporting shaft 68 which is driven by the first replenishing motor started to drive when the first selecting key was operated at the same time the wait flag is set to 34 1 34 and the timer n1 for counting the prohibition time is started v at step s614 it is decided whether the timer n1 was counted up or not when the timer n1 was counted up the process proceeds to step s615 to.