Abstract: An ink-jet recording method of forming an image with an ink-jet head, wherein the ink-jet head includes an ink chamber, an electric actuator provided in the ink chamber and an insulating layer covering the electric actuator, including steps of: feeding an ink containing a coloring material and a water-soluble solvent into ink chamber, and applying a driving voltage with a driving frequency of 10 kHz to 55 kHz onto the electric actuator so that the ink is jetted from the ink chamber so as to form the image; wherein the thickness of the insulating layer is 0.1 &mgr;m to 10 &mgr;m, and the concentration of oxygen dissolved in the ink is 4 ppm or less.

Abstract: A dispersion of colored particles is disclosed. The dispersion is prepared by emulsifying a mixture comprising a colorant and polymer, employing a reactive emulsifier, and subsequently copolymerizing the resulting mixture, employing polymerizable monomer. An ink employing the dispersion is also disclosed.

Abstract: An ID generating device and an ID verification device for improving the security of an ID code. The ID verification device, which is arranged in a device body, includes a code generation device for generating a random code string. A predetermined operation is performed on the random code string to generate a first ID code. The ID generation device is arranged in an accessory of a device body and electrically connected to the ID generation device, which receives the random code string and performs a predetermined operation on the random code string to generate a second ID code. The ID verification device receives the second ID code from the ID generation device, compares the first and second ID codes, and judges whether the accessory is valid in accordance with the comparison result.

Abstract: An ink-jet recording method of forming an image with an ink-jet head, wherein the ink-jet head comprises an ink chamber, an electric actuator provided in the ink chamber and an insulating layer covering the electric actuator, comprising steps of: feeding an ink containing a coloring material and a water-soluble solvent into ink chamber, and applying a driving voltage with a driving frequency of 10 kHz to 55 kHz onto the electric actuator so that the ink is jetted from the ink chamber so as to form the image; wherein the thickness of the insulating layer is 0.1 &mgr;m to 10 &mgr;m, and the concentration of oxygen dissolved in the ink is 4 ppm or less.

Abstract: An image data processing apparatus is described that prevents the quality of image data from being degraded by pixel quantity conversion. The apparatus includes an analog processor, a quantity converter and a binarization converter. The analog processor quantizes each of the analog element data to generate multiple-state element data, The quantity converter changes the number of plural pieces of multiple-state element data in one line to generate quantity-converted element data. The quantity converter averages at least two adjacent pieces of multiple-state element data to generate an average value as one piece of new multiple-state element data. The quantity converter further selectively outputs the new multiple-state element data and original multiple-state element data as the quantity-converted element data. The binarization converter binarizes the quantity-converted element data to generate binary element data.