Apparatus and method for forming a black image in which black ink is overlaid on color ink

An ink-jet recording apparatus for forming a black image on a recording member based on image data, said ink-jet recording apparatus comprising:

• an ink set comprising (i) a black ink having a first penetration rate, and (ii) a plurality of color inks at least one of which has a second penetration rate higher than the first penetration rate;
• determining means for determining one of a presence or an absence of an adjacent region between a color image and a black image in the image data;
• and
• deciding means for deciding in accordance with a determination by said determining means whether the black image should be formed either (i) by applying only black ink to the recording member, or (ii) by applying black ink to the recording member after the at least one of said plurality of color inks has been absorbed into the recording member;
• printing means for applying ink to the recording member to form the black image in accordance with a decision of said deciding means;
• wherein the apparatus is composed so that an ink jetting amount of the color ink per one pixel is smaller than that of the black ink when the color ink and the black ink are superposed.

An ink-jet recording method for forming a color image composed of a black image and a color image on a recording member, a part of the black image being adjacent to the color image, comprising the steps of:

• (i) providing a black ink having a first penetration rate and a color ink having a second penetration rate which is higher than the first penetration rate;
• (ii) applying the black ink to the recording member by an ink-jet ejecting method and forming the black image;
• and
• (iii) applying the color ink to the recording member by an ink-jet ejecting method and forming the color image, wherein
• step (ii) comprises the sub-step of applying the color ink to a certain position in an area where the black image adjacent to the color image is recorded, and then applying the black ink to the position where the color ink has been applied, and wherein an ink jetting amount of the color ink per one pixel is smaller than that of the black ink when the color ink and the black ink are superposed.

A process for controlling bleeding between a black image and a color image adjacent to the black image, both images being formed on a recording member by an ink-jet printing method, comprising the steps of:

• (i) applying a black ink having a first penetration rate with respect to the recording member on the recording medium and forming the black image;
• and
• (ii) applying a color ink having a second penetration rate with respect to the recording member which is higher than the first penetration rate on the recording member and forming the color image, wherein
• step (i) comprises the sub-step of applying the color ink to a certain position in an area where the black image adjacent to the color image is recorded, and then applying the black ink to the position where the color ink has been applied, and wherein an ink jetting amount of the color ink per one pixel is smaller than that of the black ink when the color ink and the black ink are superposed on the recording member.

An ink-jet recording method using an ink-jet recording apparatus configured such that at least one portion of a recording paper with a printed image including a black image thereon contacts a portion of the ink-jet recording apparatus, the black image extending to an area where the paper contacts a portion of the ink-jet recording apparatus, said method comprising the steps of:

• (i) providing a black ink and a color ink containing a larger amount of nonionic surfactant than the black ink;
• and
• (ii) applying the black ink on the recording member and forming the black image, wherein step (ii) comprises the sub-step of:
• determining whether or not an optical density of the black image in the area where the paper contacts a portion of the ink-jet recording apparatus exceeds a predetermined threshold value;
• and applying the color ink to a certain position in the area when the optical density exceeds the threshold value.

A process for forming an image including a black image on a recording medium comprising the steps of:

• (a) providing a black ink having a first penetration rate with respect to the recording medium, and a color ink having a second penetration rate with respect to the recording medium, wherein the second penetration rate is higher than the first penetration rate;
• and
• (b) applying the black ink to an area where the black image is formed on the recording medium, wherein step (b) comprises the sub-step of:
• applying the color ink to the area when an amount of black ink per unit area in the area that is to be applied to the recording medium exceeds a threshold, wherein the amount is determined according to data for the black image.

A process for forming an image including a black image on a recording medium comprising the steps of:

• (a) providing a black ink having a first penetration rate with respect to the recording medium, and color inks at least one of which has a second penetration rate with respect to the recording medium, wherein the second penetration rate is higher than the first penetration rate, and the color inks are necessary for forming black color by mixing with each other;
• and
• (b) applying the black ink to an area where the black image is formed on the recording medium, wherein step (b) comprises the sub-step of:
• applying the color inks to the area when an amount of black ink per unit area in the area that is to be applied to the recording medium exceeds a threshold, wherein the amount is determined according to data for the black image.