Canon Kabushiki Kaisha

Kaneji Yamada

Osamu Iwasaki

Naoji Otsuka

Hitoshi Sugimoto

Minoru Teshigawara

Toshiyuki Chikuma

Kiichiro Takahashi

Hitoshi Nishikori

Takeshi Yazawa

Noribumi Koitabashi

Tetsuya Edamura

Masashi Ogawa

Kiyomi Aono

Ken Hosaka

Kunihiko Ikeda

In a printer, when difference in ejection characteristic among nozzles appears as density non-uniformity and the way of letting the density non-uniformity appear is different depending upon kind of image, proper density correction is performed. Specifically, the kind of image to be printed is judged, and when the kind of image is a halftone image according to the judgment, a density correction table corresponding to the halftone image is selected and used to perform the density correction. Also when the kind of image is judged to be a solid image (without a portion of the halftone image), a proper table is selected similarly and used to perform the density correction.

Image processing apparatus and image processing method

Two sets of recording heads for applying ink of cyan (C), magenta (M), and yellow (Y) are arranged in symmetry in a scanning direction and orders of colors C and M ejected onto a pixel of a secondary color are set to symmetric orders (C&#x2192;M and M&#x2192;C). This makes the application orders of ink symmetric in each pixel of secondary color and thus there is no difference between application orders in formation of the pixel by either forward or backward scanning, whereby occurrence of uneven color due to the application orders of ink can be reduced even in execution of two-way color print.

Two-way print apparatus and print method

An apparatus and method capable of obtaining an output characteristic of the print unit and determining a correction value for an output density, without using an expensive scanner. To realize this, a nozzle array consisting of a plurality of nozzles provided in the print head is divided into a plurality of nozzle blocks &lsqb;a&rsqb; to &lsqb;d&rsqb; and each of patches is formed by using the nozzles of the same nozzle block allocated to the patch. The patches are printed in a size and shape that allows the densities of the patches to be optically detected by the density sensor. A test pattern comprising these patches is measured by the density sensor to make a density correction for each nozzle of the print head.

Test pattern printing method, information processing apparatus, printing apparatus and density variation correction method

A plurality of dot pattern formation is performed for each of a plurality of print elements. By overlaying or contacting a plurality of dots printed by the plurality of formation, a density value of a dot pattern formed on a printing medium is increased, and a test pattern whose area is enlarged is formed.

Printing apparatus and test pattern printing method

An jet recording apparatus, which records on a recording medium by discharging ink form a recording head, is provided with at least two electrothermal converting elements each having different amount of heat generation, and driven each individually, which are arranged in the ink flow path communicated with the discharge port of the recording head along the ink flow path each in different distance to the discharge port, and when the pre-discharge is performed without participating in recording, driving signals needed for discharging ink are supplied to the electrothermal converting element on the side near to the discharge port subsequent to being supplied to the electrothermal converting element on the side away from the discharge port. The pre-discharge is performed immediately before recording per line, and the number of discharges is set to be larger for the electrothermal converting element on the side away from the discharge port than the number of discharges for the electrothermal converting element on the side near to the discharge port.

Ink jet recording apparatus, ink jet recording head, and ink jet recording method

In a pre-ejected ink receiving device including a waste ink absorber for receiving ink dropped from a pre-ejection as waste ink, since ink mist flows are not controlled properly, the conventional ink-jet recording apparatus has a big problem of contamination, caused by flown up ink mist from a pre-eject port and flown out ink mist from a gap between the pre-eject port and the waste ink absorber, which is accumulated in the recording apparatus by repeated recording operation. A waste ink absorber with rough density to which an ink droplet ejected by the pre-ejection directly collides, solves the above-mentioned problem.

Waste ink absorber, pre-ejected ink receiving device and ink-jet recording apparatus

The present invention reduces a difference in speed between a main drop section and a tailing section of a ejected ink droplet by heating a front heater and a rear heater provided for one nozzle with a predetermined time lag and thus, the ink dot formed from the main drop section and the tailing section on a printing medium can be more approximate to a circle. Thereby, it is possible to prevent print quality from being degraded by the tailing section separated from the main drop section of the ink droplet ejected from an ink jet printing apparatus of serial type.

Ink jet printing apparatus and ink jet printing method

Disclosed are an ink-jet printing apparatus and cleaning control method capable of reducing density variations in printed images by controlling the number of times of wiping during image printing and capable of printing without lowering the throughput. A dot counter counts printing dots printed by ink droplets discharged from a printing head. A wiping flag &ldquo;A&rdquo; is set on the basis of the result of comparison of this count value with a predetermined threshold value. By referring to this wiping flag &ldquo;A&rdquo;, whether the ink discharge surface of the printing head is to be cleaned with a blade while the printing head is printing one page of a printing sheet is determined. When the printing sheet printed by the printing head is to be discharged, whether the ink discharge surface of the printing head is to be cleaned with the blade is determined by referring to a wiping flag &ldquo;B&rdquo; that is set on the basis of the result of comparison of the value of Nd with another threshold value.

Ink-jet printing apparatus and cleaning control method of the same

Small dots and large dots are recorded with a sufficient difference between them by such structure that a plurality of heat generating elements are disposed inside of each nozzle. A single pulse is applied to one heat generating element for recording of a small dot, whereas a single pulse and a divided pulse are applied to two heat generating elements for recording of a large dot. When the divided pulse is applied to the heat generating element, a larger amount of the ink is ejected than upon application of the single pulse. Therefore, the sufficient difference can be generated between the sizes of dots by applying the driving pulses as described above.

Ink jet recording apparatus and method

When discharging a sheet material from an image forming apparatus after completion of image formation, at least one spur roller for discharging the trailing edge of the sheet material downward is provided. Hence, it is possible to more stably discharge the sheet material than ever, and to arrange and mount sheets of the sheet material on a discharged-sheet tray in a manner better than ever.

Growing community of inventors

Tokyo, Japan

Kaneji Yamada