Image forming apparatus with selective utilization of AC voltage source

摘要

An image-forming apparatus includes a first image-forming portion; a second image-forming portion; an executing portion for executing an operation in a first mode in which an image is formed on a recording material by the first and second image-forming portions or a second mode in which an image is formed by the second image-forming portion; an AC-voltage source; a first DC-voltage source; a second DC-voltage source; and a controller for controlling the first and second DC-voltage sources and the AC-voltage source. In the first mode, application of the AC voltage by the AC-voltage source and the DC voltages by the first and second DC-voltage sources are performed, and in the second mode, application of the DC voltage by the second DC-voltage source is performed, and application of the AC voltage by the AC-voltage source and the DC voltage by the first DC-voltage source are stopped.

主权项

1. An image forming apparatus comprising:
a first image forming portion, including a first photosensitive member and a first charger for electrically charging the first photosensitive member, for forming an image on a recording material by using the first photosensitive member and the first charger; a second image forming portion, including a second photosensitive member and a second charger for electrically charging the second photosensitive member, for forming an image on the recording material by using the second photosensitive member and the second charger; an executing portion for selectively executing an operation in one of a plurality of modes including a first mode in which the image is formed on the recording material by using said first and second image forming portions and including a second mode in which the image is formed on the recording material by using the second image forming portion without using the first image forming portion; an AC voltage source for applying an AC voltage to both the first charger and the second charger in common; a first DC voltage source for applying a DC voltage to the first charger; a second DC voltage source for applying a DC voltage to the second charger; and a controller for controlling said first DC voltage source, said second DC voltage source and said AC voltage source so that: when the operation in the first mode is executed, application of the AC voltage by said AC voltage source and application of the DC voltages by said first and second DC voltage sources are performed, and when the operation in the second mode is executed, application of the DC voltage by said second DC voltage source is performed, and application of the AC voltage by said AC voltage source and application of the DC voltage by said first DC voltage source are stopped.