Image forming apparatus and method

An image forming method for forming color images on a surface of a recording medium by a plurality of full line type inkjet heads separately arranged for a plurality of inks of different colors, each of the inkjet heads having a nozzle row wherein a plurality of nozzles for discharging droplets of the ink are arranged though a length corresponding to a full width of the recording medium, and discharging the droplets of the inks from the plurality of inkjet heads toward the surface of the recording medium, while causing 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, the method comprising the steps of:

• using ultraviolet curable inks as the inks;
• during a formation of an image by successive ink discharges of respective colors by the plurality of inkjet heads, performing a first curing process of irradiating ultraviolet light from an ultraviolet light source comprising a group of light emitting elements arranged in a linear form, onto the droplets of the ink deposited on the surface of the recording medium by a preceding one of the inkjet heads before discharge of the droplets of the ink by a subsequent one of the inkjet heads, in such a manner that the droplets of the ink deposited by the preceding inkjet head are semi-cured to a degree whereby the droplets of the ink discharged by the inkjet head of a preceding color in an ink discharge sequence do not mix on the surface of the recording medium with the droplets of the ink of another color discharged by the subsequent inkjet head;
• controlling, for said first curing process, 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
• performing a second curing process of irradiating ultraviolet light for performing main curing of the droplets of the ink on the surface of the recording medium after the droplets of the ink have been discharged by a last one of the inkjet heads, to a degree whereby image degradation does not occur upon subsequent handling of the cured droplets of the ink,
• wherein a wavelength range used in said first curing process is narrower than a wavelength range used in said second curing process.

An image forming apparatus, comprising:

• a discharge head having nozzles which discharge droplets of an ink toward a surface of a recording medium;
• a conveyance device which causes the discharge head and the recording medium to move relatively to each other by conveying at least one of the discharge head and the recording medium;
• a semiliquid forming curing device which causes the droplets of the ink discharged from the discharge head on a upstream side thereof to cure to a semiliquid state having a viscosity sufficient to prevent color mixing even if the droplets of the ink make contact with droplets of an ink of another color, the semiliquid forming curing device being disposed on a downstream side of the discharge head in a direction of relative conveyance of the recording medium with respect to the discharge head, wherein the semiliquid forming curing device comprises a light source including a group of light emitting elements arranged in a substantially linear form;
• a flattening device which flattens the droplets of the ink on the surface of the recording medium, the flattening device being disposed on a downstream side of the semiliquid forming curing device;
• and
• a main curing device which performs main curing of the droplets of the ink on the surface of the recording medium to a degree whereby image degradation caused by ink smearing does not occur during subsequent conveyance and handling, the main curing device being disposed on a downstream side of the flattening device,
• wherein a wavelength range of said semiliquid forming device is narrower than a wavelength range of said main curing device.

An image forming method for forming images on a surface of a recording medium by discharging ink from a discharge head having nozzles for discharging droplets of the ink toward the surface of the recording medium and causing the discharge head and the recording medium to move relatively to each other by conveying at least one of the discharge head and the recording medium, the method comprising:

• a discharge step of discharging droplets of an ink curable by application of energy onto the recording medium by means of the discharge head;
• a semiliquid forming curing step of causing the droplets of the ink discharged in the discharge step to cure to a semiliquid state having a viscosity sufficient to prevent color mixing even if the droplets of the ink make contact with droplets of an ink of another color on the surface of the recording medium, the semiliquid forming curing step irradiating light from a light source comprising a group of light emitting elements arranged in a substantially linear form;
• a flattening step of flattening the droplets of the ink by applying pressure to the droplets of the ink in the semiliquid state on the surface of the recording medium;
• and
• a main curing step of performing main curing of the droplets of the ink on the surface of the recording medium, after the flattening step, to a degree whereby image degradation caused by ink smearing does not occur during subsequent conveyance and handling,
• wherein a wavelength range used in said semiliquid forming curing step is narrower than a wavelength range used in said main curing step.

An image forming apparatus, comprising:

• an ink discharge device comprising a plurality of frill 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 frill 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 frirthest downstream position of the inkjet heads,
• wherein light intensity irradiated by said first curing device is smaller than light intensity irradiated by said second curing device.

An image forming method for forming color images on a surface of a recording medium by a plurality of full line type inkjet heads separately arranged for a plurality of inks of different colors, each of the inkjet heads having a nozzle row wherein a plurality of nozzles for discharging droplets of the ink are arranged through a length corresponding to a full width of the recording medium, and discharging the droplets of the inks from the plurality of inkjet heads toward the surface of the recording medium, while causing 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, the method comprising the steps of:

• using ultraviolet curable inks as the inks;
• during a formation of an image by successive ink discharges of respective colors by the plurality of inkjet heads, performing a first curing process of irradiating ultraviolet light from an ultraviolet light source comprising a group of light emitting elements arranged in a liner form, onto the droplets of the ink deposited on the surface of the recording medium by a preceding one of the inkjet heads before discharge of the droplets of the ink by a subsequent one of the inkjet heads, in such a manner that the droplets of the ink deposited by the preceding inkjet head are semi-cured to a degree whereby the droplets of the ink discharged by the inkjet head of a preceding color in an ink discharge sequence do not mix on the surface of the recording medium with the droplets of the ink of another color discharged by the subsequent inkjet head;
• controlling, for said first curing process, 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
• performing a second curing process of irradiating ultraviolet light for performing main curing of the droplets of the ink on the surface of the recording medium after the droplets of the ink have been discharged by a last one of the inkjet heads, to a degree whereby image degradation does not occur upon subsequent handling of the cured droplets of the ink,
• wherein light intensity irradiated in said first curing process is smaller than light intensity irradiated in said second curing process.

An image forming apparatus, comprising:

• a discharge head having nozzles which discharge droplets of an ink toward a surface of a recording medium;
• a conveyance device which causes the discharge head and the recording medium to move relatively to each other by conveying at least one of the discharge head and the recording medium;
• a semiliquid forming curing device which causes the droplets of the ink discharged from the discharge head on a upstream side thereof to cure to a semiliquid state having a viscosity sufficient to prevent color mixing even if the droplets of the ink make contact with droplets of an ink of another color, the semiliquid forming curing device being disposed on a downstream side of the discharge head in a direction of relative conveyance of the recording medium with respect to the discharge head, wherein the semiliquid forming curing device comprises a light source including a group of light emitting elements arranged in a substantially linear form;
• a flattening device which flattens the droplets of the ink on the surface of the recording medium, the flattening device being disposed on a downstream side of the semiliquid forming curing device;
• and
• a main curing device which performs main curing of the droplets of the ink on the surface of the recording medium to a degree whereby image degradation caused by ink smearing does not occur during subsequent conveyance and handling, the main curing device being disposed on a downstream side of the flattening device,
• wherein light intensity irradiated by said semiliquid forming curing device is smaller than light intensity irradiated by said main curing device.

An image forming method for forming images on a surface of a recording medium by discharging ink from a discharge head having nozzles for discharging droplets of the ink toward the surface of the recording medium and causing the discharge head and the recording medium to move relatively to each other by conveying at least one of the discharge head and the recording medium, the method comprising:

• a discharge step of discharging droplets of an ink curable by application of energy onto the recording medium by means of the discharge head;
• a semiliquid forming curing step of causing the droplets of the ink discharged in the discharge step to cure to a semiliquid state having a viscosity sufficient to prevent color mixing even if the droplets of the ink make contact with droplets of an ink of another color on the surface of the recording medium, the semiliquid forming curing step irradiating light from a light source comprising a group of light emitting elements arranged in a substantially linear form;
• a flattening step of flattening the droplets of the ink by applying pressure to the droplets of the ink in the semiliquid state on the surface of the recording medium;
• and
• a main curing step of performing main curing of the droplets of the ink on the surface of the recording medium, after the flattening step, to a degree whereby image degradation caused by ink smearing does not occur during subsequent conveyance and handling,
• wherein light intensity irradiated in said semiliquid forming curing step is smaller than light intensity irradiated in said main curing step.

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 an irradiation range of said first curing device is narrower than an irradiation range of said second curing device.

An image forming method for forming color images on a surface of a recording medium by a plurality of full line type inkjet heads separately arranged for a plurality of inks of different colors, each of the inkjet heads having a nozzle row wherein a plurality of nozzles for discharging droplets of the ink are arranged through a length corresponding to a fUll width of the recording medium, and discharging the droplets of the inks from the plurality of inkjet heads toward the surface of the recording medium, while causing 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, the method comprising the steps of:

• using ultraviolet curable inks as the inks;
• during a formation of an image by successive ink discharges of respective colors by the plurality of inkjet heads, performing a first curing process of irradiating ultraviolet light from an ultraviolet light source comprising a group of light emitting elements arranged in a linear form, onto the droplets of the ink deposited on the surface of the recording medium by a preceding one of the inkjet heads before discharge of the droplets of the ink by a subsequent one of the inkjet heads, in such a manner that the droplets of the ink deposited by the preceding inkjet head are semi-cured to a degree whereby the droplets of the ink discharged by the inkjet head of a preceding color in an ink discharge sequence do not mix on the surface of the recording medium with the droplets of the ink of another color discharged by the subsequent inkjet head;
• controlling, for said first curing process, 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 inlcjet head and a reflectivity of the recording medium;
• and
• performing a second curing process of irradiating ultraviolet light for performing main curing of the droplets of the ink on the surface of the recording medium after the droplets of the ink have been discharged by a last one of the inkjet heads, to a degree whereby image degradation does not occur upon subsequent handling of the cured droplets of the ink,
• wherein an irradiation range for said first curing process is narrower than an irradiation range for said second curing process.

An image forming apparatus, comprising:

• a discharge head having nozzles which discharge droplets of an ink toward a surface of a recording medium;
• a conveyance device which causes the discharge head and the recording medium to move relatively to each other by conveying at least one of the discharge head and the recording medium;
• a semiliquid forming curing device which causes the droplets of the ink discharged from the discharge head on a upstream side thereof to cure to a semiliquid state having a viscosity sufficient to prevent color mixing even if the droplets of the ink make contact with droplets of an ink of another color, the semiliquid forming curing device being disposed on a downstream side of the discharge head in a direction of relative conveyance of the recording medium with respect to the discharge head, wherein the semiliquid forming curing device comprises a light source including a group of light emitting elements arranged in a substantially linear form;
• a flattening device which flattens the droplets of the ink on the surface of the recording medium, the flattening device being disposed on a downstream side of the semiliquid forming curing device;
• and
• a main curing device which performs main curing of the droplets of the ink on the surface of the recording medium to a degree whereby image degradation caused by ink smearing does not occur during subsequent conveyance and handling, the main curing device being disposed on a downstream side of the flattening device,
• wherein an irradiation range of said semiliquid forming curing device is narrower than an irradiation range of said main curing device.

An image forming method for forming images on a surface of a recording medium by discharging ink from a discharge head having nozzles for discharging droplets of the ink toward the surface of the recording medium and causing the discharge head and the recording medium to move relatively to each other by conveying at least one of the discharge head and the recording medium, the method comprising:

• a discharge step of discharging droplets of an ink curable by application of energy onto the recording medium by means of the discharge head;
• a semiliquid forming curing step of causing the droplets of the ink discharged in the discharge step to cure to a semiliquid state having a viscosity sufficient to prevent color mixing even if the droplets of the ink make contact with droplets of an ink of another color on the surface of the recording medium, the semiliquid fonning curing step irradiating light from a light source comprising a group of light emitting elements arranged in a substantially linear form;
• a flattening step of flattening the droplets of the ink by applying pressure to the droplets of the ink in the semiliquid state on the surface of the recording medium;
• and
• a main curing step of performing main curing of the droplets of the ink on the surface of the recording medium, after the flattening step, to a degree whereby image degradation caused by ink smearing does not occur during subsequent conveyance and handling,
• wherein an irradiation range for said semiliquid forming curing step is narrower than an irradiation range for said main curing step.

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 inkiet 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 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;
• and
• a light control source unit which controls the group of light emitting elements in such a manner that the ultraviolet light is emitted selectively from the group of light emitting elements, controls an irradiation range of the group of light emitting elements, and controls light intensity irradiated by each of the light emitting elements according to reflectivity of the recording medium in such a manner that the higher the reflectivity of the recording medium is, the smaller the light intensity irradiated by each of the light emitting elements is.

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 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;
• and
• a light control source unit which determines volume of droplets of the ink deposited in an irradiation area of one of the light emitting elements on the recording medium according to image data relating to an image to be printed on the recording medium, and controls light intensity irradiated by each of the light emitting elements according to the volume of droplets of the ink deposited in the irradiation area in such a manner that the larger the volume of droplets of the ink deposited in the irradiation area is, the larger the light intensity irradiated by each of the light emitting elements is.