Abstract: A liquid ejection head according to the present invention includes a plurality of ejection openings arranged in a first direction and a plurality of electro-thermal transducers for ejecting liquid from the ejection openings, the liquid ejection head and a printing medium being subjected to the relative movement, wherein an arrangement pitch of the ejection openings forming an end group located in the respective opposite end section along the first direction is longer than an arrangement pitch of the ejection openings forming a central group located in the central section along the first direction. According to the present invention, it is possible to eliminate white streaks which may generate in a solid printing.

Abstract: The present invention provides an ink jet printing apparatus and an ink jet printing method in which if an image is printed using ink and a process liquid serving to improve the printability of the ink, degradation of print image quality can be suppressed which results from a rise in the temperature of a print head. To achieve this, the present invention reduces the amount of process liquid ejected from a process liquid ejection section capable of ejecting a process liquid, with increasing temperature of an ink ejection section capable of ejecting ink.

Abstract: There is provided an ink jet printing apparatus and a printing method capable of reducing unevenness due to a time lag. An ink jet printing apparatus comprise a printing head including a first and a second eject port array. The second eject port array is shorter than said first eject port array in said conveying direction of the printing medium. The first eject port array has a first a second. The first eject port group is disposed parallel to said second eject port array. The second eject port group is not disposed parallel to the second eject port array. In an identical printing area of the printing medium, a printing ratio of the first eject port group is lower than that of the second eject port group. The second ink contains a component that reduces dispersion stability of the first ink.

Abstract: A liquid recording head for effecting recording by ejecting droplets from a plurality of ejection outlets formed on a substrate is provided. The liquid recording head includes a plurality of large droplet ejection outlets each having a relatively large ejection amount, a plurality of small droplet ejection outlets each having a relatively small ejection amount, energy generating elements for generating energy for ejecting the droplets from the plurality of large droplet ejection outlets and the plurality of small droplet ejection outlets, a liquid chamber for retaining liquid to be ejected from the plurality of large droplet ejection outlets or the plurality of small droplet ejection outlets, at least two first flow passages for establishing communication between the liquid chamber and one of the large droplet ejection outlets, and second flow passages for establishing communication between the liquid chamber and the small droplet ejection outlets.

Abstract: There is provided a liquid ejecting method using a liquid ejection head including a first ejection port for ejecting an ink containing a color material, a first energy generating element for generating energy utilized for ejecting the ink from the first ejection port, a second ejection port for ejecting an improvement liquid for improving recording property of the ink, and a second energy generating element for generating energy utilized for ejecting the improvement liquid from the second ejection port. The method includes ejecting the ink from the first ejection port by driving the first energy generating element, and ejecting the improvement liquid from the second ejection port by driving the second energy generating element, in a state where a liquid level of the improvement liquid in the second ejection port has moved forward in a liquid ejection direction than a liquid level of the ink in the first ejection port when the first energy generating element is driven.

Abstract: An ink set for ink jet recording includes a black ink and a plurality of color inks of different colors. The black ink contains a pigment as a coloring material. The color ink having the highest brightness among the plurality of color inks has the highest surface tension among the plurality of color inks. The difference in surface tension between the black ink and the color ink having the highest brightness is 2 dyn/cm (mN/m) or less.

Abstract: The present invention relates to an ink supply method and a printing apparatus by which, when an ink supply operation is repeated by using a gas-liquid separation member, damage to the gas-liquid separation member can be reduced to improve the reliability. In order to realize this, an ink supply method for aspirating air in a sub tank via the gas-liquid separation member to supply ink from a supply opening into the sub tank sets a plurality of different amounts as an suction amount of air in the sub tank per a unit time.

Abstract: The present invention relates to measures for preventing end deviation that may occur during high-duty printing such as one-pass printing, and in particular, to measures for preventing density unevenness (white stripes) in the case of ink with a low lightness such as black ink. According to the present invention, the amount of black ink ejected through the corresponding ejection ports is set to be larger than that of color ink ejected through the corresponding ejection ports. Two black ink ejection chips each having at least one black ink ejection port row are arranged on the respective sides of a color ink ejection chip.

Abstract: A liquid-discharge recording head includes large nozzles for discharging large liquid drops and medium and small nozzles for discharging medium and small liquid drops that are smaller than the large liquid drops. The large nozzles are arranged on one side of an ink-supply opening and the medium and small nozzles are arranged on the other side of the ink-supply opening. The number of large nozzles is greater than the number of medium and small nozzles, and the liquid-discharge recording head performs high-speed printing using the large nozzles, high-speed photo printing using the medium and small nozzles, and high-quality photo printing using the small nozzles.

Abstract: An inkjet recording head using pigment ink as discharged ink includes a nozzle member having a nozzle for discharging ink. The nozzle member has an ink-repellent layer forming a discharge port face having a discharge port that is an open end of the nozzle. The ink jet recording head further includes a projection portion positioned around the discharge port and protruding along a central axis of the nozzle with respect to the discharge port face. The nozzle, in a cross section passing through the central axis of the nozzle, has an outline shape provided with a curved line having a changing curvature radius. A point at which the curvature radius of the curved line is minimum is included in the projection portion and has a maximum height from the discharge port face in the cross section.

Abstract: An adverse effect of air flows occurring near the nozzle line with high print duty is reliably avoided by appropriately dividing and allocating the print data to a plurality of ink ejection nozzle lines. When the print head is scanning in a forward direction, a combination of a magenta ink nozzle line and a yellow ink nozzle line that do not adjoin each other is mainly used. When the print head is scanning in a backward direction, another combination of a magenta ink nozzle line and a yellow ink nozzle line that do not adjoin each other is mainly used.

Abstract: A color ink jet printing apparatus is provided which can print high quality color images and black letters without increasing a running cost and a printing time while using nozzle arrays with poor first ejection stability. For this purpose, inks with good first ejection stability are printed overlappingly at those of pixel positions printed by another nozzle array where the first ejection stability problem is likely to be caused by the latter nozzle array ejecting an ink with poor first ejection stability. This makes the first ejection stability problem less conspicuous on a printed image while taking full advantage of desirable characteristics of the inks used.

Abstract: There is provided an ink jet printing apparatus and a printing method capable of reducing unevenness due to a time lag. An ink jet printing apparatus comprise a printing head including a first and a second eject port array. The second eject port array is shorter than said first eject port array in said conveying direction of the printing medium. The first eject port array has a first a second. The first eject port group is disposed parallel to said second eject port array. The second eject port group is not disposed parallel to the second eject port array. In an identical printing area of the printing medium, a printing ratio of the first eject port group is lower than that of the second eject port group. The second ink contains a component that reduces dispersion stability of the first ink.

Abstract: A liquid ejection head according to the present invention includes a plurality of ejection openings arranged in a first direction and a plurality of electro-thermal transducers for ejecting liquid from the ejection openings, the liquid ejection head and a printing medium being subjected to the relative movement, wherein an arrangement pitch of the ejection openings forming an end group located in the respective opposite end section along the first direction is longer than an arrangement pitch of the ejection openings forming a central group located in the central section along the first direction. According to the present invention, it is possible to eliminate white streaks which may generate in a solid printing.

Abstract: A liquid ejection head according to the present invention includes a plurality of ejection openings arranged in a first direction and a plurality of electro-thermal transducers for ejecting liquid from the ejection openings, the liquid ejection head and a printing medium being subjected to the relative movement, wherein an arrangement pitch of the ejection openings forming an end group located in the respective opposite end section along the first direction is longer than an arrangement pitch of the ejection openings forming a central group located in the central section along the first direction. According to the present invention, it is possible to eliminate white streaks which may generate in a solid printing.

Abstract: An ink set for ink jet recording includes a black ink and a plurality of color inks of different colors. The black ink contains a pigment as a coloring material. The color ink having the highest brightness among the plurality of color inks has the highest surface tension among the plurality of color inks. The difference in surface tension between the black ink and the color ink having the highest brightness is 2 dyn/cm (mN/m) or less.

Abstract: A color ink jet printing apparatus is provided which can print high quality color images and black letters without increasing a running cost and a printing time while using nozzle arrays with poor first ejection stability. For this purpose, inks with good first ejection stability are printed overlappingly at those of pixel positions printed by another nozzle array where the first ejection stability problem is likely to be caused by the latter nozzle array ejecting an ink with poor first ejection stability. This makes the first ejection stability problem less conspicuous on a printed image while taking full advantage of desirable characteristics of the inks used.

Abstract: A liquid recording head for effecting recording by ejecting droplets from a plurality of ejection outlets formed on a substrate is provided. The liquid recording head includes a plurality of large droplet ejection outlets each having a relatively large ejection amount, a plurality of small droplet ejection outlets each having in a relatively small ejection amount, energy generating elements for generating energy for ejecting the droplets from the plurality of large droplet ejection outlets and the plurality of small droplet ejection outlets, a liquid chamber for retaining liquid to be ejected from the plurality of large droplet ejection outlets or the plurality of small droplet ejection outlets, at least two first flow passages for establishing communication between the liquid chamber and each of first ejection outlets; and a second flow passage for establishing communication between the liquid chamber and at least two second ejection outlets.

Abstract: An object of the present invention is to provide an ink jet recording apparatus which can keep an adequate absorptivity of an ink absorbing member for a long period of time, even when such inks which react with each other are sucked through the same cap in a sucking recovery operation, by preventing a mixed ink collected by the ink absorbing member from thickening or being solidified. The ink jet recording apparatus has: a recovery unit 8 and 62 for draining ink from a black-ink discharge portion 13 for discharging black ink and a color-ink discharge portion 14 for discharging color ink which reacts with the black ink; an ink absorbing member 31 for collecting the ink which is drained by the recovery unit and separating the ink into a solid part 41 and a liquid part 42; and an ink introduction unit 7 for introducing the ink which is drained by the recovery unit, into the ink absorbing member.

Abstract: A liquid-discharge recording head includes large nozzles for discharging large liquid drops and medium and small nozzles for discharging medium and small liquid drops that are smaller than the large liquid drops. The large nozzles are arranged on one side of an ink-supply opening and the medium and small nozzles are arranged on the other side of the ink-supply opening. The number of large nozzles is greater than the number of medium and small nozzles, and the liquid-discharge recording head performs high-speed printing using the large nozzles, high-speed photo printing using the medium and small nozzles, and high-quality photo printing using the small nozzles.