EP0488724A2
Expired / Lapsed
EP
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Ink jet recording apparatus and method
Assignee: Canon Inc
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Filing: 1991-11-28
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Granted: —
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Expires: 2011-11-28
Abstract
Abstract An ink jet recording apparatus and method for forming an image including a text region and a halftone region. The text region contains at least a part of a character and/or a thin line thinner than a predetermined thickness, and the halftone region contains a dot image on a recording medium. An image is formed by ejecting ink from recording heads (51-54) in response to an input signal. The apparatus or method identifies the text region and the halftone region of an image on the basis of the input signal, expels black ink onto a recording area on the recording medium (58) so as to form at least a part of the text region in a first scanning of the recording heads, expels a plurality of inks (Y, M, C, K) including the black ink (K) onto the recording area so as to form at least a part of the text and the halftone regions in a second scanning, and repeating the first scanning and the second scanning on the next recording area after incrementing the recording medium.
Inventors
- 👤 Hiromitsu C/O Canon Kabushiki Kaisha Hirabayashi
- 👤 Hiroshi C/O Canon Kabushiki Kaisha Tajika
- 👤 Noribumi C/O Canon Kabushiki Kaisha Koitabashi
- 👤 Miyuki C/O Canon Kabushiki Kaisha Matsubara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 06:59
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/205; B41J2/2056; B41J11/00; B41J11/009; B41J11/0095; B41J2/21; B41J2/2132; G; G06; G06K; G06K15/00; G06K15/02; G06K15/10; G06K15/102; G06K15/18; G06K15/1867; G06K15/1869; G06K15/1871; H; H04; H04N; H04N1/00; H04N1/40; H04N1/40062; H04N1/46; H04N1/56; H04N1/60; H04N1/6016; H04N1/6022; B41J2/2052; G06K2215/00; G06K2215/0082; G06K2215/0094
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
175 words
An ink jet recording apparatus for performing recording on a recording medium by depositing ink onto the recording medium in response to a recording data signal, which characterized by comprising: a plurality of recording heads for ejecting inks; moving means for relatively moving said recording heads and said recording medium; recording medium identifying means for identifying a type of said recording medium; image identifying means for identifying a recording data signal corresponding to a text region which includes at least a part of a character and/or a line thinner than a predetermined thickness, and for identifying a recording data signal corresponding to a halftone region including a dot image; recording data signal processing means for processing said recording data signal based on identification result by said image identifying means; and recording controlling means for controlling ink ejection of said recording head and movement by said moving means in accordance with the identification result by said image identifying means and on the basis of the recording data signal processed by said recording data signal processing means.
Claim 2
Dependent Claim
98 words
An ink jet recording apparatus as claimed in claim 1, characterized in that said image identifying means by comprises: black signal generating means for generating a first black signal by suppressing chromatic components of said recording data signal; black signal binarizing means, connected to an output of said black signal generating means, for binarizing said first black signal outputted from said black signal generating means; and black image identifying means, connected to an output of said black signal generating means, for identifying said text regions, or said halftone regions on the basis of the binary first black signal.
Claim 3
Dependent Claim
108 words
An ink jet recording apparatus as claimed in claim 2, characterized in that said black signal generating means comprises: a maximum value detector for detecting a maximum value of R, G and B components of said recording data signal; a minimum value detector for detecting a minimum value of the R, G and B components of said recording data signal; a substracter for substracting said minimum value from said maximum value; a multiplier for multiplying an output of said subtracter by a predetermined fixed value; an adder for adding sais maximum value and an output of said multiplier; and a limiter for limiting an output of said adder.
Claim 4
Dependent Claim
145 words
An ink jet recording apparatus as claimed in claim 2, characterized in that said black signal binarizing means comprises: means for producing first black signals of a pixel of interest and its neighboring pixels; averaging means for calculating an average value of said first black signals of said pixels of interest and its neighboring pixels; first comparing means for comparing said average value with the black signal of said pixel of interest to produce a second black signal of said pixel of interest representing that said pixel of interest is black; and second comparing means for comparing a difference of said average value and the first black signal of said pixel of interest with a predetermined value to produce a differential signal representative of difference between a black level of said pixel of interest and an average value of black levels of its neighboring pixels.
Claim 5
Dependent Claim
152 words
An ink jet recording apparatus as claimed in claim 4, characterized in that said black image identifying means comprises: means for producing second black signals of a pixel of interest and of its neighboring pixels by delaying said second black signal outputted from said first comparing means; means for producing an isolation indicating signal of the pixel of interest by comparing the second black signal of the pixel of interest with the second black signals of its neighboring pixels; means for producing a third black signal representing that the pixel of interest is black when said isolation indicating signal, said second black signal and said differential signal of said pixel of interest are all indicating black level, and means for producing fourth black signal representing that the pixel of interest is a part of text region based on said third black signals of the pixel of interest and of its neighboring pixels.
Claim 6
Dependent Claim
44 words
An ink jet recording apparatus as claimed in claim 5, characterized in that said recording data signal processing means suppresses said color components of said recording data signal when said fourth black signal indicates that the pixel of interest is in a text region.
Claim 7
Dependent Claim
34 words
An ink jet recording apparatus as claimed in claim 6, characterized in that said recording controlling means controls said recording heads so that each color components of said recording data signal is directly recorded.
Claim 8
Dependent Claim
71 words
An ink jet recording apparatus as claimed in claim 1, characterized in that said recording controlling means controls, when said recording medium identifying means identifies that the recording medium is of low ink absorption, said recording heads so that each color component of said recording data signal corresponding to said halftone region is recorded once, while black component of said recording data signal corresponding to said text regions is recorded twice.
Claim 9
Dependent Claim
70 words
An ink jet recording apparatus as claimed in claim 1, characterized in that said recording heads include four heads, each of which corresponds to each one of four colors of black, cyan, magenta and yellow, and is divided into a plurality of sections each including a plurality of orifices aligned along a subscanning direction, and said recording controlling means controls said recording heads so that selected sections sequentially eject ink.
Claim 10
Dependent Claim
31 words
An ink jet recording apparatus as claimed in claim 1, characterized in that each of said recording heads generates film boiling which grows bubbles for expelling ink by using thermal energy.
Claim 11
Dependent Claim
26 words
An ink jet recording apparatus as claimed in claim 1, characterized in that said recording heads include two or more recording heads for ejecting black ink.
Claim 12
Dependent Claim
168 words
An ink jet recording method for forming on a recording medium an image including a text region that contains at least a part of a character and/or a thin line thinner than a predetermined thickness, and a halftone region that contains a dot image by ejecting ink from recording heads in response to an input signal, said method characterized by comprising the steps of: identifying the text region and the halftone region of said image on the basis of said input signal; expelling black ink onto a recording area on the recording medium so as to form at least a part of the text region in a first scanning of said recording heads; expelling a plurality of inks including the black ink onto said recording area so as to form at least a part of the text and the halftone regions in a second scanning of said recording heads; and repeating the first scanning and the second scanning on the next recording area after incrementing the recording medium.
Claim 13
Dependent Claim
57 words
An ink jet recording method as claimed in claim 12, characterized in that each of said recording heads is divided into a plurality of sections, and the steps for expelling black ink and a plurality of inks are sequentially performed from bottom sections to top sections by incrementing the recording medium by a length of the sections.
Claim 14
Dependent Claim
55 words
An ink jet recording method as claimed in claim 12, characterized in that the text region is recorded by depositing black ink twice on the same recording area, and the halftone region is recorded by separately depositing color inks in a staggered pattern and in a counter-staggered pattern, to which the halftone region is divided.
Claim 15
Dependent Claim
34 words
An ink jet recording method as claimed in claim 12, characterized in that the step of expelling black ink is executed by two recording heads ejecting black ink in response to the input signal.
Claim 16
Dependent Claim
25 words
An ink jet recording method as claimed in claim 12, characterized in that the text region is recorded by using black ink and cyan ink.
Claim 17
Dependent Claim
24 words
An ink jet recording method as claimed in claim 12, further characterized by comprising the step of identifying a type of said recording medium.
Claim 18
Dependent Claim
55 words
An ink jet recording method as claimed in claim 17, characterized in that each color component of said recording data signal corresponding to said halftone region is recorded once, while black component of said recording data signal corresponding to said text region is recorded twice, when the recording medium is of low ink absorption power.
References Cited (Backward Citations)
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