| 摘要 |
<P>PROBLEM TO BE SOLVED: To effectively use developer in a cartridge in a configuration capable of executing different printing modes. <P>SOLUTION: The image forming apparatus includes: a replaceable cartridge with an agitating member for agitating developer by rotating; a light receiving element 82 for receiving light emitted from a light emitting element and passed through the cartridge; developer quantity estimating means 12 for estimating a quantity of developer in the cartridge based on a light reception signal; determining means 13 for determining that the cartridge has reached its replacement time if the quantity of developer exceeds a first threshold; image forming means 11 configured to execute a normal printing mode and a low speed printing mode; image formation amount counting means 14 for counting a value relating to an amount of image formation in the low speed printing mode; and diagnostic mode executing means 15 for executing diagnosis determined by the determining means 13, while rotating the agitating member at the same rotating speed as that of the normal printing mode if a count value of the image formation amount count means 14 exceeds at least a predetermined count value. <P>COPYRIGHT: (C)2012,JPO&INPIT |
