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US 8,540,343 B2Granted
Image forming apparatus
AssigneeFUJIFILM Corporation
InventorYasuhiko Kachi
Life of this patent
Estimating the term…
Abstract
An image forming apparatus which includes a line head having a nozzle group in a two-dimensional matrix configuration, or a line head in which a plurality of head modules are joined together in a staggered matrix arrangement.
Claims20
An image forming apparatus comprising:
- a liquid ejection head having an ejection surface in which a plurality of nozzles that eject liquid droplets are arranged two-dimensionally;
- a conveyance device which conveys a recording medium on which the liquid droplets ejected from the plurality of nozzles of the liquid ejection head are deposited;
- a main body frame which supports the conveyance device;
- a head movement device which supports the liquid ejection head movably with respect to the main body frame;
- and
- a head fixing device which fixes the movable liquid ejection head to the main body frame at a position for droplet ejection onto the recording medium, wherein:
- the head fixing device has a pressure application device for head fixing which impels the liquid ejection head in a width direction of the recording medium which is perpendicular to a conveyance direction in which the conveyance device conveys the recording medium, and
- wherein a spring constant of the pressure application device for head fixing and a mass of the liquid ejection head are set so that a resonance (f1) satisfies formula (1) below:
- f1=(2π)−1×(k1/m1)1/2 (1)
- where f1 is the resonance frequency, k1 is the spring constant of the pressure application device for head fixing, m1 is the mass of the liquid ejection head;
- wherein the resonance frequency (f1) is different from a component of a vibration pitch which is dependent on a spatial distance in the conveyance direction between a pair of nozzles which correspond to a joint section of a nozzle alignment forming adjacent dots in the width direction on the recording medium, of distances between nozzles in the conveyance direction in nozzle arrangement of the liquid ejection head, a relative vibration in the width direction between the conveyance device and the liquid ejection head during conveyance of the recording medium, and a conveyance speed at which the conveyance device conveys the recording medium, and wherein a condition represented by formula (2) below is met:
- |sin{π·OSy·fv/vp}|≦¼ (2)
- where OSy is the spatial distance, fv is the relative vibration frequency, and vp is the conveyance speed.
10 more elements
An image forming apparatus comprising:
- a liquid ejection head in which a plurality of head modules each having a plurality of nozzles that eject liquid droplets are arranged in a staggered configuration;
- a conveyance device which conveys a recording medium on which the liquid droplets ejected from the plurality of nozzles of the liquid ejection head are deposited;
- a main body frame which supports the conveyance device;
- a head movement device which supports the liquid ejection head movably with respect to the main body frame;
- and
- a head fixing device which fixes the movable liquid ejection head to the main body frame at a position for droplet ejection onto the recording medium, wherein:
- the head fixing device has a pressure application device for head fixing which impels the liquid ejection head in a width direction of the recording medium which is perpendicular to a conveyance direction in which the conveyance device conveys the recording medium, and
- wherein a spring constant of the pressure application device for head fixing and a mass of the liquid ejection head are set so that a resonance (f1) satisfies formula (1) below:
- f1=(2π)−1×(k1/m1)1/2 (1)
- where f1 is the resonance , k1 is the spring constant of the pressure application device for head fixing, m1 is the mass of the liquid ejection head;
- wherein the resonance (f1) is different from a component of a vibration pitch which is dependent on a spatial distance in the conveyance direction between a pair of nozzles which correspond to a module joint section of a nozzle alignment forming adjacent dots in the width direction on the recording medium, of distances between nozzles in the conveyance direction in nozzle arrangement of the liquid ejection head, a relative vibration frequency in the width direction between the conveyance device and the liquid ejection head during conveyance of the recording medium, and a conveyance speed at which the conveyance device conveys the recording medium, and wherein a condition represented by formula (2) below is met:
- |sin{π·OSy·fv/vp}|¼ (2)
- where OSy is the spatial distance, fv is the relative vibration frequency, and vp is the conveyance speed.
10 more elements
Dependencies are inferred from the claim text.