Patent ID: 7510277
Filing Date: 2009-03-31
Classification: B41J

Abstract:
1. An image forming apparatus, comprising: an ink discharge device comprising a plurality of full line type inkjet heads arranged separately for a plurality of inks of different colors, each of the inkjet heads having a nozzle row in which a plurality of nozzles for discharging droplets of the ink toward a surface of a recording medium are arranged through a length corresponding to a full width of the recording medium; an ink supply device which supplies ultraviolet curable inks of corresponding colors to the inkjet heads; a conveyance device which causes the inkjet heads and the recording medium to move relatively to each other by conveying at least one of the recording medium and the inkjet heads in a direction substantially perpendicular to a breadthways direction of the recording medium; a first curing device which irradiates ultraviolet light for causing the droplets of the ink, deposited on the surface of the recording medium by one of the inkjet heads on an upstream side in a direction of relative conveyance of the recording medium with respect to the inkjet heads, to semi-cure to a degree whereby the droplets of the ink discharged from the inkjet head on the upstream side do not mix on the surface of the recording medium with the droplets of the ink discharged by a next one of the inkjet heads situated on a downstream side in the direction of relative conveyance, the first curing device comprising an ultraviolet light source including a group of light emitting elements arranged in a linear form and disposed between the inkjet heads of the respective colors; a light source control device which controls at least one of a light emission range and a light emission intensity of the group of light emitting elements, in accordance with at least one condition of a width of the recording medium, a range of ink deposited by the inkjet head and a reflectivity of the recording medium; and a second curing device which irradiates ultraviolet light for performing main curing of the droplets of the ink on the recording medium to a degree whereby image degradation does not occur upon subsequent handling of the cured droplets of the ink, the second curing device being disposed after one of the inkjet heads situated in a furthest downstream position of the inkjet heads, wherein a wavelength range of said first curing device is narrower than a wavelength range of said second curing device.