EP0817112A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Ink-jet printing method and apparatus therefor
Assignee: Canon Inc
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Filing: 1997-06-18
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Granted: —
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Expires: 2017-06-18
Abstract
Abstract Each nozzle of an ink-jet head has heaters having different heating capacities, and in accordance with the heater driven, a diameter of an ink dot formed by ink which is discharged from the nozzle is changed, thereby printing a large dot or a small dot. When multi-value image data is inputted, the multi-value image data is modulated such that a pixel having high density is printed with both the large dot and small dot. On the basis of the modulated print data, any of the heaters included in each nozzle of the ink-jet head is driven, whereby printing an image having tones based on the multi-value image data.
Inventors
- 👤 Naoji Ohtsuka
- 👤 Kiichiro Takahashi
- 👤 Hitoshi Nishikori
- 👤 Osamu Iwasaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 00:53
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/21; B41J2/2121; B41J2/2128; G; G06; G06K; G06K15/00; G06K15/02; G06K15/10; G06K15/102
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
124 words
An ink-jet printing apparatus for printing an
image on a print medium by discharging ink from each of
a plurality of printing elements of a printhead,
characterised by comprising: ink-discharge-amount changing means (607, 609) for
altering an amount of ink discharged from each of the
printing elements of the printhead; modulate means (204, 205) for modulating print
data such that an additional dot is provided as density
of print data increases; timing control means (200) for determining ink
discharge timing to discharge the amount of ink which is
altered by said ink-discharge-amount changing means; and control means (202) for outputting the print data
modulated by said modulate means to the printhead in
synchronization with the ink discharge timing determined
by said timing control means.
Claim 2
Dependent Claim
43 words
The ink-jet printing apparatus according to claim
1, characterised in that said timing control means
determines ink discharge timing for at least printing a
large dot by the printing elements, and ink discharge
timing for printing a small dot by the printing elements.
Claim 3
Dependent Claim
81 words
The ink-jet printing apparatus according to claim
1 or 2, characterised in that said ink-discharge-amount
changing means comprises either a plurality of heat
resistance units each of which having different heating
capacities, or a plurality of heat resistance units each
of which being provided on different locations for a
single printing element, and said ink-discharge-amount
changing means changes the discharge amount of ink by
changing the number and/or the location of heat
resistance units to be driven in substantially
simultaneous timing.
Claim 4
Dependent Claim
42 words
The ink-jet printing apparatus according to claim
1, characterised in that said control means controls at
least a small dot or combination of a large dot and a
small dot to express tone of the print data modulated by
said modulate means.
Claim 5
Dependent Claim
75 words
The ink-jet printing apparatus according to anyone
of claims 1-4, characterised by further comprising: scan-data generating means for generating print
data corresponding to each scanning by dividing the
print data into data which corresponds to each scanning
and modulating the divided data in accordance with
modulation data; and multiple pass control means for performing
printing by a plurality of times of scanning on the
basis of the print data generated by said scan-data
generating means.
Claim 6
Dependent Claim
23 words
The ink-jet printing apparatus according to claim
5, characterised in that the modulation data is random-number
data provided in correspondence with each
scanning.
Claim 7
Dependent Claim
33 words
The ink-jet printing apparatus according to anyone
of claims 1-6, wherein the printhead discharges ink
utilizing thermal energy, and includes a thermal energy
generator for generating thermal energy to be provided
to ink.
Claim 8
Dependent Claim
112 words
An ink-jet printing apparatus for performing
printing by relatively moving a print medium and a
printhead, characterised by comprising: ink-discharge-amount changing means (607, 609) for
altering an amount of ink discharged from the printhead; modulate means (204, 205) for modulating multi-value
image data to generate print data; and print means (200, 202) for performing printing by
changing the amount of ink discharged from the printhead
by said ink-discharge-amount changing means, on the
basis of the print data modulated by said modulate means, wherein each pixel of a multi-value image printed
by said print means is formed by at least one small dot
or combination of a large dot and a small dot.
Claim 9
Dependent Claim
46 words
The ink-jet printing apparatus according to claim
8, characterised in that said print means performs
printing by scanning the printhead for a plurality of
times, and said modulate means generates print data by
modulating the multi-value image data in correspondence
with each scanning of the printhead.
Claim 10
Dependent Claim
88 words
An ink-jet printing method of printing an image on
a print medium by discharging ink from each of a
plurality of printing elements of a printhead,
characterised by comprising the steps of: modulating (S12) print data such that an
additional dot is provided as density of print data
increases; printing (S15, S16) an image on the print medium
by outputting the print data modulated in said
modulating step in synchronization with ink discharge
timing of each printing element of the printhead which
alters respective discharge amount of ink.
Claim 11
Dependent Claim
43 words
The ink-jet printing method according to claim 10,
characterised in that the ink discharge timing includes
ink discharge timing for at least printing a large dot
by the printing elements, and ink discharge timing for
printing a small dot by the printing elements.
Claim 12
Dependent Claim
84 words
The ink-jet printing method according to claim 10
or 11, characterised in that the amount of ink discharged by
the printhead is altered by a plurality of heat
resistance units each of which having different heating
capacities, or a plurality of heat resistance units each
of which being provided on different locations for a
single printing element, wherein the number and/or the
location of the heat resistance units to be driven in
substantially simultaneous timing is changed to alter
the amount of ink discharge.
Claim 13
Dependent Claim
44 words
The ink-jet printing method according to claim 10,
characterised in that printing is performed such that
tone of the print data modulated in said modulating step
is expressed by at least a small dot or combination of a
large dot and a small dot.
Claim 14
Dependent Claim
78 words
The ink-jet printing method according to anyone of
claims 10-13, further comprising: a scan-data generating step of generating print
data corresponding to each scanning by dividing the
print data into data which corresponds to each scanning
and modulating the divided data in accordance with
modulation data; and a multiple pass control step (S21-S23) of
performing printing by the printhead scanning for a
plurality of times on the basis of the print data
generated in said scan-data generating step.
Claim 15
Dependent Claim
87 words
An ink-jet printing method for performing printing
by relatively moving a print medium and a printhead,
characterised by comprising the steps of: modulating (S12) multi-value image data to
generate print data; and performing (S15, S17) printing by changing the
amount of ink discharged from the printhead in
accordance with the print data modulated in said
modulating step, wherein in said printing step, each pixel of a
multi-value image printed is formed by at least one
small dot or combination of a large dot and a small dot.
Claim 16
Dependent Claim
50 words
The ink-jet printing method according to claim 15,
characterised in that in said printing step, printing is
performed by scanning the printhead for a plurality of
times, and in said modulating step, print data is
generated by modulating the multi-value image data in
correspondence with each scanning of the printhead.
Claim 17
Dependent Claim
67 words
An ink jet recording apparatus having at least one
recording head with at least one recording element for
discharging liquid to form dots on a recording medium or
method or a control circuit for controlling operation of
a recording head for an ink jet recording apparatus,
wherein the diameter of a dot produced by a recording
element is modulated in accordance with the data to be
recorded.
Claim 18
Dependent Claim
60 words
An ink jet recording apparatus having at least one
recording head with at least one recording element for
discharging liquid to form dots on a recording medium or
method or a control circuit for controlling operation of
a recording head for an ink jet recording apparatus,
having the features recited in any one or any combination
of the preceding claims.
References Cited (Backward Citations)
No citation records indexed.
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