Patents by Inventor Keiji Tomizawa

Keiji Tomizawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7938511
    Abstract: Provided are a printing head and an inkjet printing apparatus, which eject liquid droplets without leaving behind any bubble in each nozzle, thus having an enhanced durability. An ejection port of the printing head includes a first ejection port part communicating with the atmosphere and a second ejection port part having a cross-section orthogonal to an ejection direction being larger than a cross-section of the first ejection port part orthogonal to the ejection direction, and being formed between the energy effect chamber and the first ejection port part. In addition, the second ejection port part is formed to be eccentric to an electrothermal transducing element in an ink supply direction in which ink is supplied from an ink supplying port to the bubbling chamber.
    Type: Grant
    Filed: August 27, 2008
    Date of Patent: May 10, 2011
    Assignee: Canon Kabushiki Kaisha
    Inventors: Keiji Tomizawa, Mikiya Umeyama, Toru Yamane, Chiaki Muraoka, Yuichiro Akama, Masaki Oikawa, Tomotsugu Kuroda
  • Publication number: 20110084999
    Abstract: An objective is to provide an inkjet print apparatus and an inkjet print method capable of a print without concentration unevenness. To achieve the objective, in a multiple-pass print using mask patterns each having low-print-percentage areas and high-print-percentage areas, the print-percentage difference between high-print-percentage areas and low-print-percentage areas is cancelled out in left-edge and right-edge parts of an image to be printed.
    Type: Application
    Filed: October 4, 2010
    Publication date: April 14, 2011
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Masayuki Kyoshima, Masaki Oikawa, Keiji Tomizawa
  • Publication number: 20110074884
    Abstract: To provide an inkjet head which includes high-density nozzle rows and which does not easily cause an ejection failure due to adhesion of ink mist around ejection orifices when a high-density image of a secondary color is printed with a small number of paths. An inkjet head includes at least two or more types of nozzle rows that eject different amounts of ink. When A is the cross section, with respect to an ink supplying direction, of an ink supply path from each ejection orifice to a supply port and L is the length of the ink supply path, the value of A/L differs between the two or more types of nozzle rows. The nozzle row of which the value of A/L is small is disposed outside an area between the nozzle rows that eject a largest amount of ink and that are arranged next to each other.
    Type: Application
    Filed: September 28, 2010
    Publication date: March 31, 2011
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Chiaki Muraoka, Yasushi Iijima, Tomotsugu Kuroda, Naoko Tsujiuchi, Mikiya Umeyama, Masaki Oikawa, Yuichiro Akama, Keiji Tomizawa
  • Publication number: 20100328384
    Abstract: An inkjet printing apparatus and an inkjet printing method are provided which can minimize air current disturbances that occur between the print head and the print medium and also minimize density unevenness caused by mask patterns. For this purpose, the 2-pass printing is performed such that the high printing ratio region and the low printing ratio region are alternated every pixel in the nozzle-arrayed direction and that adjoining groups of high printing ratio regions are separated from one another by a group of low printing ratio regions that forms a passage wide enough for air currents to pass through.
    Type: Application
    Filed: June 16, 2010
    Publication date: December 30, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Masayuki Kyoshima, Masaki Oikawa, Keiji Tomizawa
  • Publication number: 20100289843
    Abstract: A printing apparatus prints on a printing medium by scanning a printhead having a plurality of nozzle arrays in a first direction and a second direction opposite to the first direction, and has a structure in which an air flow entering the nozzle array in the scan of the printhead in the first direction becomes larger than an air flow entering the nozzle array in the scan of the printhead in the second direction. The apparatus increases, in scanning in the second direction, discharge speed of ink discharged from at least one nozzle array arranged leeward in the scanning direction of the printhead from a predetermined position on the printhead in the scanning direction to be higher than or equal to the discharge speed of ink discharged from at least one nozzle array arranged windward in the scanning direction of the printhead from the predetermined position.
    Type: Application
    Filed: April 28, 2010
    Publication date: November 18, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Keiji Tomizawa, Masaki Oikawa, Masayuki Kyoshima
  • Patent number: 7832843
    Abstract: A liquid ejecting head includes plural ejection outlets for ejecting droplets; liquid flow paths in fluid communication with the ejection outlets; and a liquid supply opening for supplying the liquid to the liquid flow paths. The ejection outlets include first and second ejection outlets disposed at least at one side of the liquid supply opening and are staggered. The first ejection outlets are nearer to the liquid supply opening than the second ejection outlets. Each of first recording elements corresponding to the first ejection outlets includes one rectangular heat generating resistor having a long side extending along a direction crossing with an arranging direction of the ejection outlets. Each of second recording elements corresponding to the second ejection outlets comprises plural rectangular heat generating resistors which are adjacent to each other at long sides thereof and are electrically connected in series.
    Type: Grant
    Filed: August 23, 2007
    Date of Patent: November 16, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Oikawa, Mineo Kaneko, Ken Tsuchii, Toru Yamane, Keiji Tomizawa, Mitsuhiro Matsumoto, Shuichi Ide, Kansui Takino, Naozumi Nabeshima
  • Patent number: 7784904
    Abstract: A liquid ejecting head includes a plurality of nozzles, each including an ejection outlet for ejecting a droplet, an ejection energy generating element, disposed at a position opposing the ejection outlet, for generating energy for ejecting a droplet, a pressure chamber provided with the ejection energy generating element and fluidly communicating with the ejection outlet, and a supply passage for supplying the liquid to the pressure chamber. The nozzles include a first nozzle and a second nozzle, which are connected with respective supply passages having lengths different from each other. The first nozzle and the second nozzle are disposed at one end portion with respect to a widthwise direction of an elongated supply chamber for supplying the liquid to the first nozzle.
    Type: Grant
    Filed: August 25, 2008
    Date of Patent: August 31, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Shuichi Ide, Mineo Kaneko, Ken Tsuchii, Toru Yamane, Masaki Oikawa, Keiji Tomizawa, Mitsuhiro Matsumoto, Kansui Takino
  • Patent number: 7771026
    Abstract: A liquid recording head includes a thermal energy generating element, having a flat plate configuration, for generating a bubble by thermal energy; a pressure chamber in which the thermal energy generating element is provided; a flow path for introducing liquid into the pressure chamber; a supply port in fluid communication with the flow path; and an ejection outlet provided at a position opposing the thermal energy generating element in fluid communication with the pressure chamber. The thermal energy generating element includes a first major surface facing the ejection outlet and a second major surface opposite the first major surface, and a distance between the first major surface and a ceiling surface of the pressure chamber in which the ejection outlet is formed is shorter than a distance between the second major surface and a bottom surface of the pressure chamber.
    Type: Grant
    Filed: October 3, 2007
    Date of Patent: August 10, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Shuichi Ide, Mineo Kaneko, Ken Tsuchii, Toru Yamane, Masaki Oikawa, Keiji Tomizawa, Mitsuhiro Matsumoto, Kansui Takino, Naozumi Nabeshima
  • Publication number: 20100188465
    Abstract: An object of the present invention is to provide an ink jet print head having plural types of nozzles arranged on the same substrate and through which ink droplets of different sizes are ejected, the ink jet print head exhibiting acceptable ejection performance regardless of the type of the nozzle. Thus, according to the present invention, each of the plural types of nozzles includes a bubbling chamber having an ejection energy generating element allowing an ink droplet to be ejected to a position located opposite an ejection port and an ejection port portion allowing the ejection port and the bubbling chamber to communicate with each other. Ratio of opening area of the ejection port portion at a position where the ejection port portion and the bubbling chamber communicate with each other, to the opening area of the ejection port is higher for the nozzle with a smaller ejection amount.
    Type: Application
    Filed: April 1, 2010
    Publication date: July 29, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Mitsuhiro Matsumoto, Mineo Kaneko, Ken Tsuchii, Toru Yamane, Masaki Oikawa, Keiji Tomizawa, Shuichi Ide, Kansui Takino, Naozumi Nabeshima
  • Patent number: 7735962
    Abstract: An object of the present invention is to provide an ink jet print head having plural types of nozzles arranged on the same substrate and through which ink droplets of different sizes are ejected, the ink jet print head exhibiting acceptable ejection performance regardless of the type of the nozzle. Thus, according to the present invention, each of the plural types of nozzles includes a bubbling chamber having an ejection energy generating element allowing an ink droplet to be ejected to a position located opposite an ejection port and an ejection port portion allowing the ejection port and the bubbling chamber to communicate with each other. Ratio of opening area of the ejection port portion at a position where the ejection port portion and the bubbling chamber communicate with each other, to the opening area of the ejection port is higher for the nozzle with a smaller ejection amount.
    Type: Grant
    Filed: August 21, 2008
    Date of Patent: June 15, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Mitsuhiro Matsumoto, Mineo Kaneko, Ken Tsuchii, Toru Yamane, Masaki Oikawa, Keiji Tomizawa, Shuichi Ide, Kansui Takino, Naozumi Nabeshima
  • Publication number: 20100091067
    Abstract: A liquid recording head includes an element substrate on which ejection energy generating elements for generating energy for ejecting droplets of liquid are provided in a staggered arrangement; ejection outlets provided opposed to the ejection energy generating elements; ejection energy generation chambers enclosing the ejection energy generating elements; and a flow path constituting member constituting first and second nozzles for supplying the liquid into the ejection energy generation chamber, wherein the second nozzles have flow path lengths shorter than those of the first nozzle, and the first and second nozzles are arranged alternately, wherein an average height of the path of the first nozzles is larger than that of the second nozzles.
    Type: Application
    Filed: December 14, 2009
    Publication date: April 15, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Keiji TOMIZAWA, Ken TSUCHII
  • Patent number: 7695088
    Abstract: A scanning speed for a carriage and a number of multi-pass are set in accordance with print density information of dots obtained from image data. This makes it possible to preferably output an image free from the occurrence of an end deviation without reducing throughput to a required extent or more.
    Type: Grant
    Filed: December 11, 2007
    Date of Patent: April 13, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Toru Yamane, Mineo Kaneko, Ken Tsuchii, Masaki Oikawa, Keiji Tomizawa, Mitsuhiro Matsumoto, Shuichi Ide, Kansui Takino
  • Publication number: 20100053277
    Abstract: A present invention provides a print head improving an ink refill speed to reduce the time from the end of ejection of ink droplets until the beginning of next ejection of ink droplets and maintaining the high quality of images obtained by printing. An ink jet print head has an ejection port portion 10 including a first ejection port portion 16 communicating with atmosphere, and a second ejection port portion 17 having a cross section which extends in a direction orthogonal to an ejecting direction and which is larger than that of the first ejection port portion 16; the second ejection port portion 17 is formed between a bubbling chamber 9 and the first ejection port portion 16. In the ink jet print head, the ejection port portion first axis 12 is located away from the ejection port portion second axis 14.
    Type: Application
    Filed: August 21, 2009
    Publication date: March 4, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Mitsuhiro Matsumoto, Keiji Tomizawa, Shuichi Murakami
  • Publication number: 20100045748
    Abstract: An ink-jet recording head includes a discharge-port portion including a first discharge-port portion continuing from a discharge port, and a second discharge-port portion communicating the first discharge-port portion with a bubble generation chamber. The second discharge-port portion has an end surface that includes a border portion bordering the first discharge-port portion and is parallel to a main surface of an element substrate. The cross-sectional area of the second discharge-port portion, anywhere from an opening surface facing the bubble generation chamber to an end surface facing the first discharge-port portion, that is parallel to the main surface of the element substrate, is larger than the area of the border portion. The cross-section of the opening surface of the second discharge-port portion has a length in a direction perpendicular to an arrangement direction of the discharge ports that is greater than its length in a direction parallel to the arrangement direction.
    Type: Application
    Filed: October 27, 2009
    Publication date: February 25, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Keiji Tomizawa, Shuichi Murakami
  • Publication number: 20100045719
    Abstract: While the print head is reduced in size, the adverse effect of air flows produced by ink droplets as they are ejected from a small number of ejection opening arrays is minimized. A small number of first ejection opening arrays eject one of three primary colors—cyan, magenta and yellow—, and a large number of second and third ejection opening arrays eject the remaining two primary colors. A fourth ejection opening array, disposed between the first ejection opening array and second or third ejection opening array.
    Type: Application
    Filed: August 6, 2009
    Publication date: February 25, 2010
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Yuichiro Akama, Keiji Tomizawa, Toru Yamane, Masaki Oikawa, Genji Inada, Mikiya Umeyama, Chiaki Muraoka, Tomotsugu Kuroda
  • Patent number: 7654648
    Abstract: A liquid recording head includes an element substrate on which ejection energy generating elements for generating energy for ejecting droplets of liquid are provided in a staggered arrangement, ejection outlets provided opposed to the ejection energy generating elements, ejection energy generation chambers enclosing the ejection energy generating elements, and a flow path constituting member constituting first and second nozzles for supplying the liquid into the ejection energy generation chambers. The second nozzles have flow path lengths shorter than those of the first nozzles, the first and second nozzles are arranged alternately, and an average height of the paths of the first nozzles is greater than that of the paths of the second nozzles.
    Type: Grant
    Filed: March 1, 2007
    Date of Patent: February 2, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Keiji Tomizawa, Ken Tsuchii
  • Publication number: 20090315945
    Abstract: A present invention improves the impact accuracy of ejected droplets, the quality of printed images, and print speed. A print head according to the present invention has an ink channel for which the width thereof in a direction orthogonal to an ink supply direction in which ink is supplied from an ink supply port to a pressure chamber is smaller than that of a pressure chamber. In the print head, the center of a heater along the ink supply direction is offset from the center of the pressure chamber along the ink supply direction, toward the side of the pressure chamber far from the ink supply port in the ink supply direction.
    Type: Application
    Filed: June 17, 2009
    Publication date: December 24, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Masaki Oikawa, Keiji Tomizawa, Mikiya Umeyama, Toru Yamane, Yuichiro Akama, Chiaki Muraoka, Tomotsugu Kuroda, Shingo Nagata, Satoshi Kudo
  • Patent number: 7628472
    Abstract: An ink-jet recording head includes a discharge-port portion including a first discharge-port portion continuing from a discharge port, and a second discharge-port portion communicating the first discharge-port portion with a bubble generation chamber. The second discharge-port portion has an end surface that includes a border portion bordering the first discharge-port portion and is parallel to a main surface of an element substrate. The cross-sectional area of the second discharge-port portion, anywhere from an opening surface facing the bubble generation chamber to an end surface facing the first discharge-port portion, that is parallel to the main surface of the element substrate, is larger than the area of the border portion. The cross section of the opening surface of the second discharge-port portion has a length in a direction perpendicular to an arrangement direction of the discharge ports that is greater than its length in a direction parallel to the arrangement direction.
    Type: Grant
    Filed: December 30, 2003
    Date of Patent: December 8, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Keiji Tomizawa, Shuichi Murakami
  • Publication number: 20090251509
    Abstract: This invention is directed to a head substrate capable of high-quality printing even when the environmental temperature, print duty, and printhead itself change, a printhead, a head cartridge, and a printing apparatus using the printhead. The head substrate includes a plurality of heaters, a constant electric current source which generates a constant electric current used to drive the heaters, and a reference current generation circuit which generates a reference current for generating the constant electric current. The head substrate also includes a MOSFET which drives the heaters by the constant electric current obtained by driving the constant electric current source in accordance with the reference current, and a switch which determines the time for which the reference current is generated. The open-close time of the switch can be externally controlled.
    Type: Application
    Filed: March 31, 2009
    Publication date: October 8, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Keiji Tomizawa, Masaki Oikawa
  • Patent number: RE40994
    Abstract: An ink jet recording head is provided with a flow path structure capable of enhancing the discharge power, filtering performance, and discharge frequency characteristics even with liquid droplets being made small. The flow path structure thus provided in a supply path makes the flow path sectional area right angled to the liquid flow direction small, and changes the area (shape) thereof at the same time. The flow path structure is formed by a flat square column serving as a first structure for closing a part of the supply path, and plural columns serving as a second structure for closing a part of the supply path. The square column is formed on the base plate in the entire width thereof to close the supply path on the base plate side. The plural columns are arranged on the square column symmetrically with respect to the center of the supply path, and extended from the square column to the discharge port plate in the height direction of the supply path.
    Type: Grant
    Filed: December 5, 2006
    Date of Patent: November 24, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Shuichi Murakami, Keiji Tomizawa