Abstract: In an inkjet printing apparatus using plural line type inkjet printing heads for one color ink, and forming an image by dividing image data into pieces corresponding to the plural printing heads, a complementary printing operation using a simple configuration is achieved without causing a substantial decrease in printing speed even when one printing head has a poorly ejecting nozzle. When a one printing head has a poorly ejecting nozzle, a corresponding nozzle of another printing head complements the printing operation assigned to the poorly ejecting nozzle. At this time, the same piece of divided image data is fed to the one and the other printing heads. Then, the printing operation of the one printing head is made invalid only at the timing of driving the poorly ejecting nozzle, and the printing operation of the second printing head is made valid only at the timing of driving the corresponding nozzle.

Abstract: In an inkjet printing apparatus using plural line type inkjet printing heads for one color ink, and forming an image by dividing image data into pieces corresponding to the plural printing heads, a complementary printing operation using a simple configuration is achieved without causing a substantial decrease in printing speed even when one printing head has a poorly ejecting nozzle. When a one printing head has a poorly ejecting nozzle, a corresponding nozzle of another printing head complements the printing operation assigned to the poorly ejecting nozzle. At this time, the same piece of divided image data is fed to the one and the other printing heads. Then, the printing operation of the one printing head is made invalid only at the timing of driving the poorly ejecting nozzle, and the printing operation of the second printing head is made valid only at the timing of driving the corresponding nozzle.

Abstract: An ink jet printing apparatus having excellent throughput can continue a printing operation without interruption if one or more line heads falls into an unprintable state when the apparatus is printing images of the same color using a plurality of line heads. For this purpose, image data for images of the same color is divided and the divided image data is supplied to such a line head of the plurality of line heads intended to form images of the same color that is capable of ejecting ink properly, so that the ink ejectable line head performs the printing operation according to the supplied image data.

Abstract: It is an object of this invention to provide an ink jet printing apparatus having excellent throughput which can continue the printing operation without interruption if a part of line heads falls into an unprintable state when the apparatus is printing images of the same color using a plurality of line heads. For this purpose, this invention divides the image data for images of the same color and supplies the divided image data to such a line head of the plurality of line heads intended to form images of the same color which are capable of ejecting ink properly so that the ink ejectable line head perform the printing operation according to the supplied image data.

Abstract: A metal gasket excellent in sealing performance and capable of sealing with a small pressing force. The metal gasket comprises at least one metal sheath with C-shaped cross-section and a ring elastic core surrounded by the metal sheath and the metal gasket is served for sealing with aid of the contact with the sealing face tightened by exerting a force in the axis center direction, wherein the metal sheath has the worked portion with a locally thin cross-section over the whole length, and when the metal sheath is exerted with a force and deformed, the deflection in the axis direction of the metal sheath due to concentrated stress on the thin worked portion causes to form projections at the both sides of the deflection which projections are pressed onto the sealing face.

Abstract: A metal gasket excellent in sealing performance and capable of sealing with a small pressing force. The metal gasket comprises at least one metal sheath with a C-shaped cross-section and a ring elastic core surrounded by the metal sheath. The metal gasket provides a seal upon exertion of a force in the axis center direction. The metal sheath has a locally thin cross-section over the whole annular length, and when the metal sheath subject to a force and deformed, the deflection in the axis direction of the metal sheath due to concentrated stress on the thin worked portion causes the formation projections at both sides of the deflection which projections are pressed onto the sealing face to form air-tight seals.