Canon Kabushiki Kaisha

Kanon Kabushiki Kaisha

Nobuaki Sakurada

Nobuhiko Shinoda

Tadashi Ito

Fumio Ito

Hiroyashu Murakami

Masaharu Kawamura

Hideaki Kawamura

Takashi Sasaki

Yukio Mashimo

Yoshitaka Watanabe

Hiroyasu Murakami

Masayuki A Suzuki

Yuichi Sato

Masayoshi Yamamichi

Makoto Aoki

Eiichi Sato

Masami Shimizu

Nobuaki Date

Soichi Nakamoto

Shohei Ohtaki

Hiroshi Aizawa

Masayoshi Kiuchi

Jiro Moriyama

Tokuichi Tsunekawa

Takashi Uchiyama

Makoto Takayama

Mitsuru Yamamoto

Zenzo Nakamura

Mashaharu Kawamura

Masaharu Kamamura

Masahiro Thunoda

Nobuhiki Shinoda

The driving frequency of a head is changed in conformity with temperature, and density data is converted into an optimum head driving voltage in conformity with temperature, whereby the discharge driving frequency and driving voltage of the recording head become optimum under any temperature condition, and thus recording of high quality is ensured since irregularities cause by the temperature variation of the recording head are eliminated. The driving voltage is set by a drive control circuit that includes a plurality of limiters, one of which is chosen in accordance with ambient temperature.

Ink jet recording apparatus for accurately recording regardless of

The driving frequency of a head is changed in conformity with temperature, and density data is converted into an optimum head driving voltage in conformity with temperature, whereby the discharge driving frequency and driving voltage of the recording head become optimum under any temperature condition, thus recording of high quality is ensured and since irregularities caused by the temperature variation of the recording head are eliminated. The driving voltage is set by a drive control circuit that includes a plurality of limiters, one of which is chosen in accordance with ambient temperature.

Ink jet recording apparatus with driving means providing a driving

A method of and an apparatus for forming a color picture, which can provide sufficiently satisfactory picture quality and which can be made practicable in terms of cost and reliability utilizes colorants having a plurality of different densities with respect to at least one color among yellow, magenta and cyan provided to form a color picture. Assuming that the number of densities of each color of yellow, magenta and cyan is respectively N.sub.Y, N.sub.M and N.sub.C, the magnitude relation among them is set to be N.sub.M, N.sub.C &gt;N.sub.Y.

Color picture forming apparatus and method

An image forming apparatus for forming an image of a partial area of an entire image frame includes an apparatus for designating a part of a frame and apparatus for selecting an image formation operation for the predetermined area designated by the designating means or an image formation operation for the entire area. The image data corresponding to the predetermined area is read out and a histogram, indicating intensity distribution, is produced corresponding thereto. A gamma conversion characteristic is determined based on a cumulative frequency distribution produced from the histogram. The image data read out is converted in accordance with the determined gamma conversion characteristic. An image is formed on the basis of the converted image data representing the predetermined part of the frame or the entire frame. In such a partial printing, the contrast or gamma characteristic of the partial image may be appropriately corrected by a correction of the gamma characteristic according to the selection of the partial area.

Image forming apparatus which performs gamma correction on the basis of

The driving frequency of a head is changed in conformity with temperature, and density data is converted into an optimum head driving voltage in conformity with temperature, whereby the discharge driving frequency and driving voltage of the recording head become optimum under any temperature condition, and thus recording of high quality is ensured the since irregularities caused by the temperature variation of the recording head are eliminated. The driving voltage is set by a drive control circuit that includes a plurality of limiters, one of which is chosen in accordance with ambient temperature.

Ink jet recording apparatus with ambient temperature detecting means for

A digital display system connected to an exposure indicator in a camera to provide a digital display representative of the exposure value in shutter speed by an array of numerical indicators of the block number eight type. When the numerical value of shutter speed is equal to or larger than one second, the indicator which is directly to the right of the least significant digit is utilized to display an indicium representing a 'second' unit as is usual in digital stop watch art by driving a pair of upper-positioned parallel segments in the 'FIG. eight' pattern to be lit serially from the least significant digit.

Shutter speed display device for a camera

An image formation apparatus such as an ink-jet color printer has a head selection controller, a dither processor, and a selection switch for selecting the head selection controller or the dither processor. Dither processing or analog processing can be selected to reproduce any type of image with excellent quality.

Image formation apparatus

For reproducing a picture with a density gradient through printing, an overlapped region is provided in a high density dot reproduction range and a low density dot reproduction range. The switch-over between the high density dot at the overlapped region is conducted where the picture density sharply changes. This reduces the unfavorable perception of quality differences in a printed picture resulting from the switch-over between the high and low density dots.

Method and apparatus for producing a picture

An ink-jet head driver comprises: a pressure chamber filled with a recording liquid; a piezo-electric element as electrical/mechanical transducing means for enlarging the capacity of the pressure chamber at a first stage and contracting it in a second stage into the state before enlargement, thereby emitting the recording liquid; and a device for adjusting the time interval between the first and second stages to adjust the emitting velocity. The capacity of the pressure chamber is changed due to charge and discharge by a charging/discharging circuit, and charge/discharge time constants of this circuit are selectively controlled by a control unit. According to this driver, mixture of air into recording liquid in the ink-jet head when the piezo-electric element is expanded is prevented, and a variable range of a dot diameter of the recording liquid droplet can be extended, thereby improving recording quality.

Ink-jet head driving circuit

A picture-forming method comprises the steps of providing picture forming elementary particles having different optical densities; controlling the areas occupied by the respective picture forming elementary particles; and representing gradient by said different picture forming elementary particles while limiting the percentage of the gradient level area represented by the highest density elementary particle to said picture forming elementary particles to under 70% of the total area repsesented by said respective different picture forming elementary particles, thereby giving a picture which does not feel 'rough'. Apparatus is also disclosed for performing the method.

Method for forming pictures

A picture producing apparatus forms a picture comprising a plurality of picture elements with different light-reflecting properties providing different optical reflection densities using a plurality of dot forming units to provide dots of recording materials of different concentrations. The optical reflection density range of an entire original picture to be reproduced is determined and selecting circuitry responsive to that determination selects at least one of the dot forming units to form picture elements reproducing the original picture. The dot forming units vary the areas of the picture elements formed by the dots so as to represent in the reproduced picture the optical reflection density range of the original.

Picture producing apparatus using multiple dot forming units and

A video signal processing system including an A/D converting circuit for analog-to-digital converting an input video signal; a storing circuit for storing data produced from the A/D converting circuit; a coefficient multiplying circuit for multiplying the data stored at the storing circuit by coefficients; and a control circuit for controlling the coefficients for the coefficient multiplying circuit in obtaining a scanning line interpolation signal or a drop-out compensating signal.

Video signal processing system

Color image picture forming process and apparatus can provide a picture with smooth shadow portions without false contours. When a black component of a color picture data is smaller than a predetermined value, the black component is expressed by using the combination of cyan, magenta and yellow colorants. When the black component is larger than the predetermined value, it is expressed by alternately using the black colorant and the three colorant combination. In another embodiment, picture quality can be enhanced by using a black colorant having a higher density than the cyan, magenta and yellow colorants.

Color image picture forming process and apparatus which improves the

A method for forming a color image by using a plurality of coloring materials and controlling quantities of the coloring materials in each pixel to form different colors is disclosed. When a density to be reproduced for at least one of the coloring materials exceeds a density reproducible for that coloring material, the quantities of other coloring materials are reduced.

Method for forming a color image

A method for reproducing a halftone color image is disclosed, in which each picture element comprises a plurality of cells and one dot is formed for each cell. At least two colorent densities are used for at least some of the colors. When there is more than one combination of colorants which can represent a given density in a picture element, the combination having the largest number of dots is selected. In a preferred embodiment, more colorants of different densities are used for cyan and magenta then are used for black and yellow.

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Yokohama, Japan

Nobuaki Sakurada