| 摘要 |
PURPOSE:To correctly detect the presence/absence of toner with a simple method by deciding the presence/absence of the toner based on a period that the detection is continuously outputted from a toner detecting means during a period that the toner is supplied by a toner supplying means. CONSTITUTION:By using the timer function of software instructing the operation of the control part 24, during the period that a toner supplying roller 13 rotates, it is judged that the toner exists when the period that a signal showing the presence of the toner is continuously outputted continues for a period decided from the rotational speed of the toner supplying roller 13, and judged that the toner is used up the period that a signal showing the absence of the toner is continuously outputted continues for a period decided from the rotational speed of the toner supplying roller 13. Thus, the presence/absence of the toner can be decided with the simple method without adding hardware, and therefore, an economical developing device can be obtained. |
