| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent fogging and toner stain caused when an image is formed on a wide recording medium after an image is formed on a narrow recording medium. <P>SOLUTION: A magnetic field generation section 56 provided in a developer conveying roller 50 has magnets 60 and nonmagnetic bodies 62 arranged alternately. Each magnet 60 is formed by connecting permanent magnet 64 and electromagnets 66A to 66C. An electromagnet control section 70 supplies electric power to electromagnets 66 arranged within a range corresponding to a paper width to produce a magnetic field only within a range of the developer conveyor roll 50 corresponding to the paper width. <P>COPYRIGHT: (C)2007,JPO&INPIT |
