EP0532302A2
Expired / Lapsed
EP
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Image recording apparatus
Assignee: Canon Inc
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Filing: 1992-09-10
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Granted: —
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Expires: 2012-09-10
Abstract
Abstract An image recording apparatus using a plurality of recording heads (9C, 9M, 9Y, 9BK) that can prevent black lines from occurring at boundaries of each scanning of the recording heads. The total recorded ink volume at the boundaries is positively reduced so that the black lines and the overflow of ink are prevented. The apparatus includes at least a pair of a dark head (26) for discharging relatively dark ink and a light head (27) for discharging relatively light ink, and separates an input image signal into image signals applied to the dark and light heads using at least two tables (23A, 23B). The two tables, one for edge nozzles of each recording head and the other for the remaining nozzles, separate the input image signal independently so that the total ink volume discharged from the edge nozzles are limited to a relatively small amount. Further, the total volume of inks discharged from the edge nozzles of the recording heads are positively reduced by performing black abstraction processing, UCR processing and black inking processing on the basis of the image signals after the separation by the tables, which image signals are linearly correspond to the ink volume.
Inventors
- 👤 Toshimitsu C/O Canon Kabushiki Kaisha Danzuka
- 👤 Akio C/O Canon Kabushiki Kaisha Suzuki
- 👤 Hisashi C/O Canon Kabushiki Kaisha Fukushima
- 👤 Yasushi C/O Canon Kabushiki Kaisha Miura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 11:59
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40087; B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/205; B41J2/2056; B41J2/21; B41J2/2132
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
139 words
An image recording apparatus which performs image recording by using a plurality of recording heads, each of said recording heads having a plurality of nozzles for discharging ink, and at least two of said recording heads discharge inks of different concentration of a same color family, said apparatus characterized by comprising: separating means having at least two types of tables for separating an image signal corresponding to the same color family, and for outputting separated image signals determining a driving duty of each of said recording heads associated with the same color family; separation control means for switching said tables in said separating means in accordance with locations of nozzles in each of said recording heads; and head driving means for driving each of said recording heads in accordance with the head driving duty determined by said separating means.
Claim 2
Dependent Claim
30 words
An image recording apparatus as claimed in claim 1, characterized in that said driving duty is the number of head driving per superpixel consisting of a predetermined number of dots.
Claim 3
Dependent Claim
50 words
An image recording apparatus as claimed in claim 1, characterized in that said separating means selects one of said tables which reduced the ink discharge volumes at the edge nozzles to a smaller amount than that at the remaining nozzles if the image signals are larger than a predetermined value.
Claim 4
Dependent Claim
38 words
An image recording apparatus as claimed in claim 1, characterized in that said separating means selects one of said tables on the basis of the image signals associated with a pixel to be recorded and its neighboring pixels.
Claim 5
Dependent Claim
48 words
An image recording apparatus as claimed in claim 1, characterized in that said separating means further comprises operation means for performing weighted summation on image signals of respective colors, and selects one of said tables in accordance with the output of said operation means and the image signals.
Claim 6
Dependent Claim
51 words
An image recording apparatus as claimed in claim 1, characterized by further comprising temperature detecting means for detecting temperature of each of said recording heads, wherein said separating means selects one of said tables in accordance with the locations of said nozzles and the temperature detected by said temperature detecting means.
Claim 7
Dependent Claim
26 words
An image recording apparatus as claimed in claim 1, characterized in that said plurality of recording heads comprise recording heads for cyan, magenta, yellow and black.
Claim 8
Dependent Claim
36 words
An image recording apparatus as claimed in claim 1, characterized in that each of said recording heads causes state transition in ink by utilizing thermal energy, and discharges ink on the basis of said state transition.
Claim 9
Dependent Claim
117 words
An image recording apparatus which performs image recording by using a recording head including a plurality of nozzles discharging black ink, said apparatus characterized by comprising: scanning means for scanning said recording head; driving means for driving said recording head so that said recording means discharges ink from said nozzles to form pixels on a recording medium, each of said pixel corresponding to one or more nozzles; control means for generating from an input image signal a signal to be supplied to said driving means; and correction means for correcting volume of said black ink struck to each edge pixel close to boundaries of a region formed by the scanning in accordance with the input image signal.
Claim 10
Dependent Claim
74 words
An image recording apparatus as claimed in claim 9, characterized in that said correction means comprises means for generating a corrected input image signal by calculating weighted summation of the input image signal associated with pixels in a matrix consisting of said edge pixel and its neighboring pixels, and correcting means for correcting volumes of black ink to be struck into each of said edge pixels in accordance with the corrected input image signal.
Claim 11
Dependent Claim
30 words
An image recording apparatus as claimed in claim 10, characterized in that said correcting means varies coefficients of the weighted summation in accordance with a type of said recording medium.
Claim 12
Dependent Claim
31 words
An image recording apparatus as claimed in claim 10, characterized in that said matrix is a one dimensional matrix arranged in the direction of a nozzle array of said recording head.
Claim 13
Dependent Claim
25 words
An image recording apparatus as claimed in claim 9, characterized in that said apparatus comprises recording heads for black, cyan, magenta, yellow and black inks.
Claim 14
Dependent Claim
49 words
An image recording apparatus as claimed in claim 13, characterized in that said control means generates the signal supplied to said head driving means in such a manner that the signal associated with the black ink is outputted second or later in order in the plurality of color inks.
Claim 15
Dependent Claim
114 words
An image processing apparatus characterized by comprising: image signal input means for outputting a first image signal including at least three signals corresponding to cyan, magenta and yellow, respectively; image signal converting means for converting at least one of the signals included in said first image signal into N (N is an integer greater than one) second image signals corresponding to N inks of different concentrations of a same color family; black abstraction means for performing black abstraction independently on each of said second image signals to produce a third signal; and signal processing means for performing a UCR processing and black inking processing on said second and third signals to produce fourth signals.
Claim 16
Dependent Claim
68 words
An image processing apparatus as claimed in claim 15, characterized in that said image signal converting means converts at least one of said signals of the first signal into the second signal including at least two signals consisting of a light second signal and a dark second signal, said light second signal and dark second signal corresponding to two inks of different concentrations of a same color family.
Claim 17
Dependent Claim
50 words
An image processing apparatus as claimed in claim 16, characterized in that said black abstraction means produces a minimum value of said light second signal or signals as a light black third signal, and produces a minimum value of said dark signal or signals as a dark black third signal.
Claim 18
Dependent Claim
84 words
An image processing apparatus as claimed in claim 17, characterized in that said signal processing means forms the fourth image signals other than the black family from each of the third image signals other than the black family by subtracting the corresponding light or dark black signal of the third signal from the corresponding third image signal, and forms the fourth image signals of the black family by multiplying each of the third image signals of the black family by a predetermined fixed value.
Claim 19
Dependent Claim
69 words
An image processing apparatus as claimed in claim 18, characterized in that said image signal converting means includes three converters independently provided for each of three colors of cyan, magenta and yellow, said converters converting image signals associated with cyan, magenta and yellow included in the first image signal into the second image signals associated with light cyan, dark cyan, light magenta, dark magenta, light yellow and dark yellow.
Claim 20
Dependent Claim
63 words
An image processing apparatus as claimed in claim 18, characterized in that said image signal converting means includes two converters independently provided for each of two colors of cyan and magenta, said converters converting image signals associated with cyan and magenta included in the first image signal into the second image signals associated with light cyan, dark cyan, light magenta, and dark magenta.
Claim 21
Dependent Claim
62 words
An image processing apparatus as claimed in claim 20, characterized in that said black abstraction means forms the third image signal including image signals associated with light cyan, dark cyan, light magenta, dark magenta, yellow, light black and dark black from the second image signals including the image signals associated with the light cyan, dark cyan, light magenta, dark magenta and yellow.
Claim 22
Dependent Claim
63 words
An image processing apparatus as claimed in claim 21, characterized in that said signal processing means forms the fourth image signal including image signals associated with light cyan, dark cyan, light magenta, dark magenta, yellow, and black from the third image signals including the image signals associated with the light cyan, dark cyan, light magenta, dark magenta, yellow, light black and dark black.
Claim 23
Dependent Claim
68 words
An image processing apparatus as claimed in claim 18, characterized in that,the fourth image signal outputted from said signal processing means is supplied to an ink jet recording apparatus, each recording head of said ink jet recording apparatus comprising an electro-thermal converting element producing thermal energy that causes film boiling in ink so that an ink droplet is discharged with the growth of bubbles by the film boiling.
Claim 24
Dependent Claim
52 words
Ink jet recording apparatus having means to prevent black lines forming at boundary portions characterised in that the means comprises an arrangement whereby inks of different concentrations can be output and the total volume of ink output can be controlled so that black lines and overflow of ink at boundaries are prevented.
References Cited (Backward Citations)
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