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(11) | EP 0 703 080 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Image forming apparatus |
| (57) An image forming apparatus uses as an image-forming agent an ink containing toner
having charged particles. The recording head (1) of the image forming apparatus has
an insulating substrate (4) formed with discharge electrodes (2), and an insulating
upper plate (13) formed with a common electrode (14). The discharge electrodes (2)
and the common electrode (14) oppose each other, and a gap serving as an ink supply
passage (20) is formed between them. The supply passage (20) is connected to an ink
supply/recovery mechanism (100), and the ink (6) is supplied from this mechanism to
the supply passage (20). A platen roller (114) serving as a counter electrode set
at the ground potential is provided ahead of the distal end of the supply passage
(20). A recording medium (108) is placed on the surface of the platen roller (114)
so as to face the recording head (1). A voltage is applied between the discharge electrodes
(2) and the common electrode (14) to form an electric field in the supply passage
(20). Thus, a toner concentration difference is formed in the ink (6) as a toner preliminary
gathering process. The toner preliminary gathering process increases the toner agglomerating
efficiency at discharge points (DP). |