| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus that achieves both size reduction and high durability at low costs.SOLUTION: An image forming unit 1K forming a black toner image is arranged most downstream in conveyance direction of an intermediate transfer belt 4, and image forming units 1Y, 1C, and 1M forming toner images in three colors are arranged on the upstream side. The image forming unit 1K includes a two-component developing device 60, lubricant application means 70, and non-contact charging means. The image forming units 1Y, 1C, and 1M each include a one-component developing device 70, and contact type charging means. The image forming units 1Y, 1C, and 1M each include a developing roller 49 having first and second inclined grooves 49a and 49b, and convex parts 52, and a cleaning blade 42 coming into contact with the convex parts 52 to regulate the amount of a one-component developer attached to the surface of a developer carrier. One of the image forming units 1Y, 1C, and 1M includes an abnormal image warning device that detects a resistance value of the non-contact charging means, and issues a warning of an abnormal image when the resistance value exceeds a predetermined value. |
