U.S. patent application number 09/217940 was filed with the patent office on 2002-04-04 for method of forming image and apparatus of the same.
Invention is credited to KOITABASHI, NORIBUMI.
Application Number | 20020039130 09/217940 |
Document ID | / |
Family ID | 26581270 |
Filed Date | 2002-04-04 |
United States Patent
Application |
20020039130 |
Kind Code |
A1 |
KOITABASHI, NORIBUMI |
April 4, 2002 |
METHOD OF FORMING IMAGE AND APPARATUS OF THE SAME
Abstract
In ink-jet printing, in order to improve fixation without using
a means such as a heater, etc even in the case of using an ink with
a slow penetration speed, black ink discharged from one head is
made to be relatively low penetrative, while a processing solution,
which is discharged from the other head and insolubilize dye of the
above black ink, is made to be relatively high penetrative. When
characters, etc. are printed on recording paper, the black ink and
the processing solution thus coalesce on the recording paper, and
the penetrability of the mixed solution becomes a given level or
higher, and this permits to accelerate the penetration and
fixation.
Inventors: |
KOITABASHI, NORIBUMI;
(YOKOHAMA-SHI, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
26581270 |
Appl. No.: |
09/217940 |
Filed: |
December 22, 1998 |
Current U.S.
Class: |
347/100 |
Current CPC
Class: |
C09D 11/32 20130101;
C09D 11/40 20130101; B41J 2/211 20130101 |
Class at
Publication: |
347/100 |
International
Class: |
G01D 011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 1997 |
JP |
9-361461 |
Dec 22, 1998 |
JP |
10-364571 |
Claims
What is claimed is:
1. A method for forming an image comprising the step of; forming an
image by using each of different plural droplets; wherein a
concentration of a surface-active agent in a droplet, into which
said different plural droplets for constituting the image to be
formed have coalesced on a printing medium surface, is the critical
micell concentration of said surface-active agent to pure water or
higher.
2. A method for forming an image as claimed in claim 1, wherein a
concentration of a surface-active agent in at least one of said
different plural droplets is less than the critical micell
concentration of said surface-active agent to pure water, and a
concentration of a surface-active agent in at least one of another
droplets is the critical micell concentration of said
surface-active agent to pure water or higher.
3. A method for forming an image as claimed in claim 1, wherein
said surface-active agents are ethylene
oxide-2,4,7,9-tetramethyl-5-decine-4, and 7-diol, and droplets, in
which concentrations of said surface-active agents are the critical
micell concentrations of said surface-active agents to pure water
or higher, have contents of 0.7% or higher in said droplets
corresponding to said surface-active agents.
4. A method for forming an image as claimed in claim 1, wherein
each of said different plural droplets is an ink droplet containing
color material.
5. A method for forming an image as claimed in claim 1, wherein
said different plural droplets contain processing solution droplets
to insolubilize the color materials in said ink droplets and
addition of said processing solution droplets onto printing medium
is performed later than at least one of ink droplets.
6. A method for forming an image as claimed in claim 4, wherein
said ink droplets contain ink droplets mainly having dyes as color
materials.
7. A method for forming an image as claimed in claim 4, wherein
said ink droplets contain ink droplets mainly having pigments as
color materials.
8. A method for forming an image as claimed in claim 4, wherein
said ink droplets contain ink droplets mainly having dyes as color
materials and ink droplets mainly having pigments as color
materials.
9. A method for forming an image as claimed in claim 7, wherein
said ink droplets mainly having pigments contain dispersing agent
for dispersing said pigments.
10. A method for forming an image as claimed in claim 7, wherein
said ink droplets mainly having pigments contain self-dispersing
type pigments.
11. A method for forming an image comprising the step of: forming
an image by using each of different plural droplets; wherein a
surface tension of a droplet, into which said different plural
droplets for constituting the image to be formed have coalesced on
a printing medium surface, is less than 35 dyne.
12. A method for forming an image as claimed in claim 11, wherein
the surface tension of at least one of said different plural
droplets is less than 35 dyne, and the surface tension of at least
one of another droplets is not less than 35 dyne.
13. A method for forming an image as claimed in claim 11, wherein
each of said different plural droplets is an ink droplet containing
color material.
14. A method for forming an image as claimed in claim 11, wherein
said different plural droplets contain processing solution droplets
to insolubilize the color materials in said ink droplets and
addition of said processing solution droplets onto printing medium
is performed later than at least one of ink droplets.
15. A method for forming an image as claimed in claim 13, wherein
said ink droplets contain ink droplets mainly having dyes as color
materials.
16. A method for forming an image as claimed in claim 13, wherein
said ink droplets contain ink droplets mainly having pigments as
color materials.
17. A method for forming an image as claimed in claim 13, wherein
said ink droplets contain ink droplets mainly having dyes as color
materials and ink droplets mainly having pigments as color
materials.
18. A method for forming an image as claimed in claim 16, wherein
said ink droplets mainly having pigments contain dispersing agent
for dispersing said pigments.
19. A method for forming an image as claimed in claim 16, wherein
said ink droplets mainly having pigments contain self-dispersing
type pigments.
20. A method for forming an image comprising the step of: forming
an image by using each of different plural droplets; wherein Ka
value of penetration speed of a droplet, into which said different
plural droplets for constituting the image to be formed have
coalesced on a printing medium surface, is not less than
5[ml/m.sup.2.multidot.msec.sup.1/2].
21. A method for forming an image as claimed in claim 20, wherein
Ka value of at least one of said different plural droplets is not
less than 5[ml/m.sup.2.multidot.msec.sup.1/2], and Ka value of at
least one of another droplets is less than
5[ml/m.sup.2.multidot.msec.sup.1/2].
22. A method for forming image as claimed in claim 20, wherein each
of said different plural droplets is an ink droplet containing
color material.
23. A method for forming an image as claimed in claim 20, wherein
said different plural droplets contain processing solution droplets
to insolubilize the color materials in said ink droplets and
addition of said processing solution droplets onto printing medium
is performed later than at least one of ink droplets.
24. A method for forming an image as claimed in claim 22, wherein
said ink droplets contain ink droplets mainly having dyes as color
materials.
25. A method for forming an image as claimed in claim 22, wherein
said ink droplets contain ink droplets mainly having pigments as
color materials.
26. A method for forming an image as claimed in claim 22, wherein
said ink droplets contain ink droplets mainly having dyes as color
materials and ink droplets mainly having pigments as color
materials.
27. A method for forming an image as claimed in claim 25, wherein
said ink droplets mainly having pigments contain dispersing agent
for dispersing said pigments.
28. A method for forming an image as claimed in claim 25, wherein
said ink droplets mainly having pigments contain self-dispersing
type pigments.
29. A method for forming an image comprising the step of: forming
an image by adding at least one of ink droplets before adding
processing solution droplet to insolubilize color materials in said
ink droplet; wherein a concentration of a surface-active agent in a
droplet, into which at least said one of ink droplets and said
processing solution constituting an image to be formed have
coalesced on a surface of a printing medium, is not less than the
critical micell concentration of said surface-active agent to pure
water.
30. A method for forming an image comprising the step of: forming
an image by adding at least one of ink droplets before adding
processing solution droplet to insolubilize color materials in said
ink droplet; wherein a surface tension of the droplet, into which
at least said one of ink droplets and said processing solution
constituting an image to be formed have coalesced on a surface of a
printing medium, is less than 35 dyne.
31. A method for foaming an image comprising the step of: forming
an image by adding at least one ink droplet before adding
processing solution droplet to insolubilize color materials in said
ink droplet; wherein Ka value indicating a penetration speed of the
droplets into which at least said one ink droplet and said
processing solution constituting an image to be formed have
coalesced on a surface of a printing medium, is not less than
5[ml/m.sup.2.multidot.msec.sup.1/2].
32. A method for forming an image comprising the step of: forming
an image by adding at least one ink droplet before adding
processing solution droplet to insolubilize color materials in said
ink droplet and then, further adding at least another ink droplet;
wherein a concentration of a surface-active agent in the droplet,
into which at least said one ink droplet and said processing
solution constituting an image to be formed have coalesced on a
surface of a printing medium, is not less than the critical micell
concentration of said surface-active agent to pure water.
33. A method for forming an image comprising the step of: forming
an image by adding at least one ink droplet before adding
processing solution droplet to insolubilize color materials in said
ink droplet and then, further adding at least another ink droplet;
wherein a surface tension of the droplet, into which at least said
one ink droplet and said processing solution constituting an image
to be formed have coalesced on a surface of a printing medium, is
less than 35 dyne.
34. A method for forming an image comprising the step of: forming
an image by adding at least one ink droplet before adding
processing solution droplet to insolubilize color materials in said
ink droplet and then, further adding at least another ink droplet;
wherein Ka value indicating a penetration speed of the droplet,
into which at least said one ink droplet and said processing
solution constituting an image to be formed have coalesced on a
surface of a printing medium, is not less than
5[ml/m.sup.2.multidot.msec.sup.1/2].
35. An image forming apparatus comprising: means for forming an
image by using discharging portions for discharging each of
different plural droplets and discharging the droplets onto a
printing medium from said discharging portions; wherein the
concentration of the surface-active agent in the droplet, into
which said different plural droplets constituting an image to be
formed have coalesced on a surface of a printing medium, becomes
riot less than the critical micell concentration of said
surface-active agent to pure water.
36. An image forming apparatus comprising: means for forming an
image by using discharging portions for discharging each of
different plural droplets and discharging the droplets onto a
printing medium from said discharging portions; wherein the surface
tension of the droplet, into which said different plural droplets
constituting an image to be formed have coalesced on a surface of a
printing medium, is less than 35 dyne.
37. An image forming apparatus comprising: means for forming an
image by using discharging portions for discharging each of
different plural droplets and discharging the droplets onto a
printing medium from said discharging portions; wherein Ka value
indicating a penetration speed of the droplet, into which said
different plural droplets constituting an image to be formed have
coalesced on a surface of a printing medium, is not less than
5[ml/m.sup.2.multidot.msec.sup.1/2].
Description
[0001] This application is based on Japanese Patent Application No.
9-361461 (1997) filed Dec. 26, 1997 and Japanese Patent Application
No. 10-364571 (1998) filed Dec. 22, 1998, the contents of which are
incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a method for forming an image and
an apparatus for forming the same, and particularly to fixing
technology in a case of forming an image by using ink and a
processing solution to insolubilize the ink.
[0004] 2. Description of the Related Art
[0005] In ink-jet printing technology for performing printing by
using solution such as this kind of ink, etc., fixation of the ink
after printing is one of important subjects. If the fixation is
poor, there is a fear of inconvenience in handling printed matters
outputted from a printer or a fear of staining other printed
matters laminated when they are arranged to be laminated for being
put into storage.
[0006] As a means for improving such fixing, an accelerator to
evaporate solvent such as water content in the ink, etc. by using a
heating means such as a heater or the like is known. The use of
such a heating means permits an across-the-board or better
improvement in fixation of ink with any penetrable speed from a
high penetrability to a low penetrability.
[0007] However, in an arrangement of using a heater, a total power
consumption of a printer becomes relatively high. Especially, when
the higher speed printing is aimed at, the shorter time is required
for fixing and the more heat quantity has to be supplied, and this
results also in a specially large power consumption. Further,
heating by heater is performed to a printing medium during feeding
or conveyance, but if the heater is arranged along the conveyance
path, a printer is upsized the more and this is not always a
suitable arrangement from a down-sizing point of view for the
equipment.
[0008] As opposed to this, it is also known that an ink with a high
penetrability is used and fixation of the ink itself is thereby
improved.
SUMMARY OF THE INVENTION
[0009] The object of the present invention is to solve at least one
of the following problems. Namely, they are:
[0010] to provide a new image-forming technology,
[0011] to improve fixation without using a means such as a heater,
etc. even when an ink with a slow penetrability is used, and
[0012] to rapidly fix an ink containing a color material such as
black, etc. while achieving a high optical density.
[0013] In a first aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0014] forming an image by using each of different plural
droplets,
[0015] wherein a concentration of a surface-active agent in a
droplet, into which the different plural droplets for constituting
the image to be formed have coalesced on a printing medium surface,
is the critical micell concentration of the surface-active agent to
pure water or higher.
[0016] Here, a concentration of a surface-active agent in at least
one of the different plural droplets may be less than the critical
micell concentration of the surface-active agent to pure water, and
a concentration of a surface-active agent in at least one of
another droplets may be the critical micell concentration of the
surface-active agent to pure water or higher.
[0017] The surface-active agents may be ethylene
oxide-2,4,7,9-tetramethyl- -5-decine-4, and 7-diol, and droplets,
in which concentrations of the surface-active agents are the
critical micell concentrations of the surface-active agents to pure
water or higher, may have contents of 0.7% or higher in the
droplets corresponding to the surface-active agents.
[0018] In a second aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0019] forming an image by using each of different plural
droplets,
[0020] wherein a surface tension of a droplet, into which the
different plural droplets for constituting the image to be formed
have coalesced on a printing medium surface, is less than 35
dyne.
[0021] Here, the surface tension of at least one of the different
plural droplets may be less than 35 dyne, and the surface tension
of at least one of another droplets may be not less than 35
dyne.
[0022] In a third aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0023] forming an image by using each of different plural
droplets,
[0024] wherein Ka value of penetration speed of a droplet, into
which the different plural droplets for constituting the image to
be formed have coalesced on a printing medium surface, is not less
than 5[ml/m.sup.2.multidot.msec.sup.1/2].
[0025] Here, Ka value of at least one of the different plural
droplets may be not less than 5[ml/m.sup.2.multidot.msec.sup.1/2],
and Ka value of at least one of another droplets may be less than
5[ml/m.sup.2.multidot.msec- .sup.1/2].
[0026] In any of the above aspects of the present invention, each
of the different plural droplets may be an ink droplet containing
color material.
[0027] The different plural droplets may contain processing
solution droplets to insolubilize the color materials in the ink
droplets and addition of the processing solution droplets onto
printing medium may be performed later than at least one of ink
droplets.
[0028] The ink droplets may contain ink droplets mainly having dyes
as color materials.
[0029] The ink droplets may contain ink droplets mainly having
pigments as color materials.
[0030] The ink droplets may contain ink droplets mainly having dyes
as color materials and ink droplets mainly having pigments as color
materials.
[0031] The ink droplets mainly having pigments may contain
dispersing agent for dispersing the pigments.
[0032] The ink droplets mainly having pigments may contain
self-dispersing type pigments.
[0033] In a fourth aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0034] forming an image by adding at least one of ink droplets
before adding processing solution droplet to insolubilize color
materials in the ink droplet,
[0035] wherein a concentration of a surface-active agent in a
droplet, into which at least the one of ink droplets and the
processing solution constituting an image to be formed have
coalesced on a surface of a printing medium, is not less than the
critical micell concentration of the surface-active agent to pure
water.
[0036] In a fifth aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0037] forming an image by adding at least one of ink droplets
before adding processing solution droplet to insolubilize color
materials in the ink droplet,
[0038] wherein a surface tension of the droplet, into which at
least the one of ink droplets and the processing solution
constituting an image to be formed have coalesced on a surface of a
printing medium, is less than 35 dyne.
[0039] In a sixth aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0040] forming an image by adding at least one ink droplet before
adding processing solution droplet to insolubilize color materials
in the ink droplet,
[0041] wherein Ka value indicating a penetration speed of the
droplet, into which at least the one ink droplet and the processing
solution constituting an image to be formed have coalesced on a
surface of a printing medium, is not less than
5[ml/m.sup.2.multidot.msec.sup.1/2].
[0042] In a seventh aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0043] forming an image by adding at least one ink droplet before
adding processing solution droplet to insolubilize color materials
in the ink droplet and then, further adding at least another ink
droplet,
[0044] wherein a concentration of a surface-active agent in the
droplet, into which at least the one ink droplet and the processing
solution constituting an image to be formed have coalesced on a
surface of a printing medium, is not less than the critical micell
concentration of the surface-active agent to pure water.
[0045] In an eighth aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0046] forming an image by adding at least one ink droplet before
adding processing solution droplet to insolubilize color materials
in the ink droplet and then, further adding at least another ink
droplet,
[0047] wherein a surface tension of the droplet, into which at
least the one ink droplet and the processing solution constituting
an image to be formed have coalesced on a surface of a printing
medium, is less than 35 dyne.
[0048] In a ninth aspect of the present invention, there is
provided a method for forming an image comprising the step of:
[0049] forming an image by adding at least one ink droplet before
adding processing solution droplet to insolubilize color materials
in the ink droplet and then, further adding at least another ink
droplet,
[0050] wherein Ka value indicating a penetration speed of the
droplet, into which at least the one ink droplet and the processing
solution constituting an image to be formed have coalesced on a
surface of a printing medium, is not less than
5[ml/m.sup.2.multidot.msec.sup.1/2].
[0051] In a tenth aspect of the present invention, there is
provided an image forming apparatus comprising:
[0052] means for forming an image by using discharging portions for
discharging each of different plural droplets and discharging the
droplets onto a printing medium from the discharging portions,
[0053] wherein the concentration of the surface-active agent in the
droplet, into which the different plural droplets constituting an
image to be formed have coalesced on a surface of a printing
medium, becomes not less than the critical micell concentration of
the surface-active agent to pure water.
[0054] In an eleventh aspect of the present invention, there is
provided an image forming apparatus comprising:
[0055] means for forming an image by using discharging portions for
discharging each of different plural droplets and discharging the
droplets onto a printing medium from the discharging portions,
[0056] wherein the surface tension of the droplet, into which the
different plural droplets constituting an image to be formed have
coalesced on a surface of a printing medium, is less than 35
dyne.
[0057] In a twelfth aspect of the present invention, there is
provided an image forming apparatus comprising:
[0058] means for forming an image by using discharging portions for
discharging each of different plural droplets and discharging the
droplets onto a printing medium from the discharging portions,
[0059] wherein Ka value indicating a penetration speed of the
droplet, into which the different plural droplets constituting an
image to be formed have coalesced on a surface of a printing
medium, is not less than 5[ml/m.sup.2.multidot.msec.sup.1/2].
[0060] According to the above arrangement, a critical micell
concentration, a surface tension, and Ka value, which represent a
penetrability of a droplet of different plural droplets such as
those of ink, processing solution, etc. joined with a printing
medium, have predetermined values or higher of a penetrability,
therefore, even if some of the individual droplets have a low
penetrability, the penetration of the joined droplets is
accelerated.
[0061] Thus, even if ink of a low penetrability are used for
improving optical density value (OD value) or suppressing
feathering, a high penetrability is shown as a coalescent one and
the fixation is not inhibited.
[0062] The above and other objects, effects, features and
advantages of the present invention will become more apparent from
the following description of the embodiments thereof taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] FIG. 1 is a chart showing a relationship between a
concentration of acetylenol contained in an ink, etc. and a fixing
time to a printing medium such as the ink, etc.;
[0064] FIG. 2 is a chart showing a relationship between a content
rate of acetylenol and K-value representing a penetration
speed;
[0065] FIGS. 3A and 3B are characteristic curves showing
relationships between a penetration quantity and an elapse of
time;
[0066] FIG. 4 is a chart showing a relationship between a content
rate of acetylenol and a surface tension;
[0067] FIG. 5 is a cross-sectional view showing a schematic
arrangement of an ink-jet printer related to an embodiment in
accordance with the present invention;
[0068] FIG. 6 is a block diagram showing an example of a control
system arrangement of the above-mentioned ink-jet printer;
[0069] FIG. 7 is a cross-sectional view showing a schematic
arrangement of an ink-jet printer related to another embodiment in
accordance with the present invention; and
[0070] FIG. 8 is a perspective illustration showing an arrangement
of an ink-jet printer related to further embodiment in accordance
with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0071] The embodiments in accordance with the present invention
have been obtained as the results of the experiments or analyses by
the inventor of the present invention.
[0072] When printing was carried out in a black (Bk) ink on a sheet
of ordinary paper and the behavior was observed, an ink with a slow
penetration almost kept staying in a state of droplet on the paper
in spite of an elapse of time, however, as soon as printing had
been done in droplet with a high penetrability superimposed on the
former printing, the two kinds of solution mixed together, and
penetrated in the paper within a relatively short time.
[0073] Providing various solutions with high penetrabilities by
admixing various concentrations of nonionic surface-active agent
such an ethylenoxide-2,4,7,9-tetramethyl-5-decyne-4,7-diol
(hereinafter also called "acetylenol." A brand name manufactured by
Kawaken Fine Chemical Co., Ltd.), and printing in these acetylenol
was done on BK ink, what is called, on solid printed image, and
fixing time was measured. In this case, when analysis was made by
varying a discharge volume of Bk ink and that of high penetrability
solution for overprinting later, then, the fixing time was about
the same as that for discharging a sum of prior mixture of Bk ink
and a high penetrability solution in volume which were discharged
separately in the above.
[0074] Namely, it is presumed that when they were. discharged
separately, the two kinds of the solutions were mixed immediately
and changed into one solution which had a uniform and an
approximately same penetrability as a previous mixture of them, and
penetrated.
[0075] Here, a further study showed as shown in FIG. 1 that when
mixed solutions of various concentrations of acetylenol were added
onto paper A with relatively poor fixation and paper B with
relatively good fixation, fixation is steeply speeded up at a
concentration of 0.7% or higher which is the critical micell
concentration of water, as illustrated by a solid line and a broken
line. In this case, paper A had a fixing time of about 1 second or
less, while paper B had 0.5 seconds or less.
[0076] Namely, the inventor of the present invention has originated
a new idea of forming an image not by one droplet image forming but
by different plural droplets of compound ink on a printing medium.
Namely, this is such a new method of image forming as a
concentration of a surface active agent in the compound ink
droplets is equal to a critical micell concentration to pure water
or higher.
[0077] Furthermore, the inventor of the present invention takes
notice of ink in ink-jet printing technology wherein one dot is
generally formed from a plurality of ink droplets and intends to
positively make use of this method to control the penetrability of
a mixed solution compounded and finally obtained.
[0078] As being obvious from the above, an embodiment of the
present invention is to use a plurality of different kinds of
solutions, to mix them on a printing medium, and to make the mixed
solution have a predetermined penetrability or higher. To be more
in details, each of a plurality of the above-mentioned solutions to
be mixed may basically have arbitrary penetrability and has only to
reveal a predetermined penetrability or higher when they are
compounded into one mixed solution. For example, some kinds of the
solutions to be mixed may have the above predetermined
penetrability or lower one, and the other kinds of the solutions
may reveal the above predetermined penetrability or higher one.
[0079] Here, concerning "kind" of a solution in this specification,
it is defined as being "different kind" when components or, more
widely, characteristics are different from each other. For example,
processing solution to insolubilize an ink and its color material,
pigment ink and dye ink among inks, further, ink containing
dispersing agent (hereinafter called "pigment ink with dispersing
agent"), and self-dispersing type ink containing no dispersing
agent (hereinafter called "ink without dispersing agent",
respectively, may comprise each solution to be mixed in accordance
with this embodiment. Further, different color inks and inks
containing different components may comprise the above-mentioned
solutions to be mixed, respectively. Furthermore, an ink containing
pigment and less component ratio of dye, and reversely, an ink
containing dye and a less component ratio of pigment may also
comprise each of the above-mentioned solutions to be mixed,
respectively.
[0080] Penetrability mentioned in this specification will briefly
be described in the following.
[0081] When penetrability is expressed by an ink volume per 1
m.sup.2, it is known that a penetration amount of ink (a unit:
ml/m.sup.2=.mu.m) can be expressed by Bristow's formula as shown
below.
V=Vr+Ka(t-tw).sup.1/2 [Formula 1:]
[0082] wherein, Lt>tw
[0083] Immediately after droplets of ink are landed on a surface of
a printing medium, the droplets of ink are mostly absorbed in
rugged part on the surface (rugged part on the surface of the
printing medium), and little is permeated into the printing medium.
This penetration time is expressed by tw (a wet time) and an
absorption volume in the rugged part is expressed by Vr. When an
elapse of time after deposition of the droplets of the ink exceeds
tw, penetration volume is increased in the volume proportional to
(1/2)th power of the exceeding time (t-tw). Ka is a proportional
factor of this increment and shows a value according to a
penetration speed.
[0084] FIG. 2 shows values of the proportional factor Ka to content
ratios of acetylenol in an ink obtained by experiments.
[0085] Ka values were measured by using a solution dynamic
penetrability measuring device S (made by Toyo Seiki Seisakusho) in
accordance with Bristow method. In these experiments, PB paper of
Canon Co., Ltd., who is the applicant of the present invention, was
used as a printing medium (recording paper). This PB paper is
usable not only for a copier or a laser beam printer (LBP) using an
electro-photographic method, but also for printing using an ink-jet
recording method.
[0086] Further, a similar result could be obtained also to PPC
paper, an electro-photographic paper of Canon Co., Ltd.
[0087] FIG. 2 shows a curve on which Ka values are increasing
(ordinate of axis) with increasing content rates (axis of
abscissa). The proportional factor Ka is determined by the content
by percentage of acetylenol. Consequently, a penetration speed of
ink substantially depends on a content rate of acetylenol. Further,
the line segments crossing the curve and in parallel with the
ordinate of axis show ranges of dispersions of the measurement
results.
[0088] FIG. 3 shows a characteristic curves of a relationship
between penetration quantity of ink and penetration speed and shows
results of the experiments on a recording paper of 64 g/mm.sup.2
weight, about 80 .mu.m thickness and about 50% percentage of
voids.
[0089] In FIG. 3A, the abscissa represents square root of an elapse
of time t (msec.sup.1/2), and in FIG. 3B, the abscissa represents
the elapse of time t (msec). Further, in both figures, the ordinate
represents penetration amount (.mu.m), and curves are in the case
of 0%, 0.35% and 1% acetylenol content, respectively.
[0090] As being obvious from both figures, the more the acetylenol
content is, the more becomes the penetration amount of ink to the
elapse of time, namely, the higher the penetrability is. In the
graphics shown in FIG. 3, such an tendency can be seen that the
higher the content of acetylenol is, the shorter the wet time tw
becomes, and also, the higher the content rate of acetylenol is,
the higher the penetrability is, even during the time before
reaching tw.
[0091] In the case of an ink containing no acetylenol (content rate
is 0%), the ink is a low or poor permeable ink. Further, in the
case that acetylenol is mixed in a rate of 1% content, the ink has
a property of permeating into recording paper in a short time and
has property as a high permeable ink which will be specified later.
And, the ink mixed with 0.35% content of acetylenol has a property
of an intermediate, semi-permeable ink between the two.
1 TABLE 1 Surface Ka value Acetylenol tension (ml/m.sup.2
.multidot. msec.sup.1/2) content (%) (dyne/cm) Poor less than 1.0
less than 0.2 40 or larger permeable ink Semi- 1.0 or more 0.2 or
more 35 or larger permeable ink but less than but less than but
smaller 5.0 0.7 than 40 High- 5.0 or more 0.7 or more smaller than
permeable ink 35
[0092] The above-mentioned table 1 shows Ka values, acetylenol
contents (%), and surface tensions (dyne/cm) to "poor permeable
ink", "semi-permeable ink", and "high permeable ink", respectively.
The higher Ka value is, the higher the penetrability of each ink to
recording paper as a printing medium becomes. Namely, the smaller
the surface tension is, the higher the penetrability is.
[0093] The Ka values in Table 1 were, as described above, obtained
from the measurements by using a solution dynamic penetrability
test device S (made by Toyo Seiki Seisakusho) in accordance with
Bristow method. In the experiments, said PB paper of Canon Co.,
Ltd. was used as recording paper. Further, similar results could be
obtained on PPC paper of said Canon Co., Ltd.
[0094] Here, the ink specified as "high permeable ink" has 0.7% or
more content of acetylenol and this is in the range of
penetrability in which the excellent result could be obtained as
described above.
[0095] Here, it is known that as a condition for containing a
surface active agent in a solution, there is a critical micell
concentration (hereinafter also called "CMC") of the surface active
agent for the solution. This critical micell concentration is a
concentration when a concentration of a surface active agent
solution is rising up and suddenly tens of molecules are associated
with each other to form micell. Acetylenol contained in the
above-described ink for preparing penetrability is a kind of
surface active agent, and a critical micell concentration exists
for this acetylenol as well according to solutions.
[0096] FIG. 4 is a characteristic curve showing a relationship with
a surface tension when the content rate of acetylenol to water was
prepared. Since there is no reduction in the surface tension when
micell is formed, it is apparent from the figure that the critical
micell concentration of acetylenol to pure water is about 0.7%.
And, comparing the CMC shown by the figure with the above Table 1,
it is apparent that the "high penetrable ink" contains acetylenol
of its CMC to pure water or higher.
[0097] Based on the above definition of penetrability, etc.,
several embodiments in accordance with the present invention will
be described below.
[0098] Embodiment 1
[0099] This embodiment is to perform printing by using an ink
containing a predetermined color material such as dye or pigment,
etc and a processing solution to make this color material
insoluble. Namely, by discharging the above-mentioned ink at first
and then adding the processing solution, a coalescent mixed
solution is formed on a printing medium, and the concentration of
the surface active agent in the solution is made to CMC of the
surface active agent to pure water or higher. Thus, a high OD value
is obtained as a result of the printing, and further, a high speed
fixing is achieved.
[0100] Moreover, in the case of the above, it is also possible to
suppress feathering and print sharper dot edges to be formed by
making the penetrability of ink lower while keeping the
concentration of the above surface-active agent in the mixed
solution. Further, when black (Bk) dye or Bk pigment is used for a
color material of the above-mentioned ink, it becomes possible to
print characters, etc. with less feathering, high OD value, and
excellent printing quality.
[0101] Moreover, regarding the dye ink and pigment ink in the above
explanation, as described above, a less component ratio of dye or
pigment may partly be contained in the pigment ink or the dye ink,
respectively. This is the same with the other embodiments which
will be described below. From this view point, an ink containing
only dye and an ink partly containing pigment in the dye are
defined as "an ink mainly with dye", while an ink containing only
pigment and an ink partly containing dye in the pigment are defined
as "an ink mainly with pigment."
[0102] Embodiment 2
[0103] In this embodiment, two kinds of ink such as dye ink and
pigment ink are prepared, and by making them coalescent on a
printing medium and then adding a processing solution thereon, a
mixture of three kinds of solutions is obtained. And, a
concentration of the surface active agent in this mixed solution is
made to CMC of the surface active agent to water or higher.
[0104] According to this embodiment, as the above-described
embodiment 1, it becomes possible to suppress feathering and print
with high OD, while achieving a high speed fixing, and furthermore,
it is possible to produce an effect that each arising problem can
be solved or relaxed when each of pigment ink and dye ink, and a
processing solution are used for printing.
[0105] Namely, when only pigment ink and processing solution are
used, a relatively strong cohesive force of the pigment generated
by a reaction with the processing solution may cause to generate
"cracks" or the like in the fixed color agent, however, in the case
of this embodiment, high viscosity reactant of the dye being
reacted with the processing solution at the same time fills the
"cracks" so that they cannot be recognized. On the other hand, when
only dye ink and processing solution are used, it is possible to
improve OD value by keeping the reactants of the processing
solution and the dye remaining relatively on the cortex of the
printing medium, however, an increase in OD value is not expectable
in many cases depending on the characteristic of the dye itself. In
the case of this embodiment, however, the inventor of the present
invention has confirmed an effect that OD value becomes higher by
such an presumed action, etc. as the dye reactants reacted with the
processing solution incorporate cohesive substances to become
relatively large particles, and thus, more particles of pigment
remain on the cortex of the printing medium.
[0106] Moreover, regarding order of putting dye ink and pigment
ink, any order produces the effect described above.
[0107] Embodiment 3
[0108] In this embodiment, an ink containing both dye and pigment
and a processing solution are made coalescent on a printing medium,
and a concentration of the surface active agent of the mixed ink is
made to CMC of the surface active agent to water or higher.
[0109] In this case, it is possible to produce the same effect as
that in the embodiment 2 described above, wherein the dye ink and
the pigment ink were put individually.
[0110] Embodiment 4
[0111] This embodiment replaces the pigment ink in the above
embodiment 2 with an ink without dispersing agent. In this case, in
addition to the effect common to the embodiments in accordance with
the present invention and the effect in the embodiment 2 described
above, it becomes possible to suppress "seepage" of fine reacted
particles of cohesive substances that is generated when an ink
without dispersing agent and a processing solution are used. In the
case of this embodiment, the applicant of the present invention
assumes that this is because the high viscosity substances of the
simultaneously reacted dye take in the above-mentioned particles
for suppressing the "seepage".
[0112] Embodiment 5
[0113] This embodiment corresponds to a case wherein an ink mixed
with dye and pigment beforehand does not contain dispersing agent
for the pigment in the embodiment 3.
[0114] In this case, an effect similar to that in the embodiment 4
can basically be obtained.
[0115] Embodiment 6
[0116] This embodiment relates to putting order of ink and
processing solution, and combinations of each ink and processing
solution are applicable to this embodiment.
[0117] For example, when printing is performed by using three
droplets of dye ink, ink without dispersing agent, and processing
solution, the inks or the processing solution are put in order of
dye ink, processing solution, and ink without dispersing agent, or
in order of ink without dispersing agent, processing solution, ad
dye ink. Namely, the processing solution is added between the two
inks added, and they are mixed on the printing medium to make the
concentration of the surface active agent in their mixed solution
to CMC of the surface active agent or higher.
[0118] In this case, it becomes possible to perform high quality
printing with relatively high OD value and suppressed
feathering.
[0119] The following are the descriptions on detailed examples of
the image-forming apparatus to which the above embodiments are
applicable.
EXAMPLE 1
[0120] FIG. 5 is a cross sectional view showing schematic
configuration of a full line type printer relating to the example
1.
[0121] This printer 1 adopts an ink-jet printing system to perform
printing by discharging or ejecting ink or processing solution from
a plurality of full line type printing heads arranged at
predetermined positions along a conveying or feeding direction of a
recording medium as a printing medium, and operates by being
controlled by the control circuit in FIG. 6 which will be described
later.
[0122] Each of the printing heads 101Bk, 101S, 101C, 101M, and 101Y
of a head group 101g has about 7200 pieces of ink discharging
portions or nozzles arrayed in the width direction (perpendicular
to this figure) of the recording paper conveyed in the direction of
A in the figure, and can operate printing on a recording paper up
to the size A3. These heads make use of thermal energy to generate
bubbles in the ink, etc. and discharge the ink or the processing
solution by the pressure of the bubbles.
[0123] The recording paper 103 is conveyed in the direction of A by
means of a pair of resist rollers driven by a conveyor or feed
motor, and is guided by a pair of guide plates 115 and is conveyed
onto a conveyor belt 111 after registration of the tip edge of the
paper. The endless conveyor belt 111 is borne by two pieces of
rollers 112, 113, and a vertical deviation on the upper part of the
belt is restricted by a platen 104. The roller 113 is driven to
rotate and the recording paper 103 is thereby conveyed. Moreover,
absorption of the recording paper 103 to the conveyor belt 111 is
done by means of electrostatic absorption. The roller 113 is driven
to rotate in the direction of conveying the recording paper in the
direction of the arrow A. The recording paper 103 printed thereon
by the printing head group 101g is ejected onto a storage tray
116.
[0124] Each head of the recording head group 101g comprised of the
black dye ink head 101Bk, the processing solution head 101S for
discharging the processing solution, each color ink head (a cyan
head 101C, a magenta head 101M, and a yellow head 101Y) is arranged
along the conveying direction A of the recording paper 103 as shown
in the figure. Here, one discharging portion of the dye ink head
101Bk has a discharging amount of 30 pl, and that of each of the
other heads has a discharging amount of 15 pl. And, it becomes
possible to print black characters and colored images by
discharging each color of ink and processing solution from each
printing head.
[0125] FIG. 6 is a block diagram showing a control configuration of
the full line type printer 1 illustrated in FIG. 5
[0126] A system controller 201 has a micro processor, a ROM for
storing a control program executed in this printing apparatus, a
RAM used as a work area when the micro processor operates
processing, etc., and executes the control of the entire printing
apparatus. A motor 204 is controlled in the driving via a driver
202, and rotates the roller 113 shown in FIG. 5 to convey the
recording paper.
[0127] A host computer 206 transfers information to be printed to
the printer 1 in accordance with this example, and controls its
printing operation. A receiving buffer 207 temporarily stores data
from the host computer 206 to keep them therein until a system
controller 201 reads the data. A frame memory 208 is a memory for
expanding printing data into image data, and has an enough size of
memory for printing. This example is described assuming that the
frame memory 208 has a memory capacity permitting to store data for
a sheet of recording paper, however, the present invention is not
to be restricted by a capacity of the frame memory.
[0128] Buffers 209S, 209P are for temporarily storing data to be
printed, and their memory capacities are variable depending on the
number of the nozzles of the printing heads. A printing control
part 210 is for properly controlling drives of the printing heads
according to the instructions from the system controller 201, and
controls a driving frequency, the number of printing data, etc.,
and also creates data for making the processing solution to be
discharged. A driver 211 drives a head part 212S as the printing
head 101S for discharging the processing solution and a head part
212P including the printing heads 101Bk, 101C, 101M, 101Y for
discharging each ink, and is controlled according to signal from
the printing control part 201.
[0129] In the above configuration, the printing data are
transferred from the host computer 206 to the receiving buffer 207
for being temporarily stored therein. Next, the stored printing
data are read by the system controller 201 and expanded to the
buffers 209S, 209P. Further, it is possible to detect
paper-jamming, ink-exhaustion, paper-out, etc. by means of each
detection signal from abnormality detection sensors.
[0130] The printing control part 210 creates data for the
processing solution for discharging it, based on the image data
expanded to the buffers 209S, 209P and controls printing actions of
each printing head based on the printing data in each buffer 209S,
209P and the data for the processing solution.
[0131] In this example, a low penetration speed ink, namely, poor
permeable ink shown in Table 1, is used for the black dye ink to be
discharged from the head 101Bk, and each high penetration speed
processing solution and ink, namely, the high penetrability ink
shown in Table 1 is used for each processing solution, cyan ink,
magenta ink and yellow ink discharged from the heads 102S, 101C,
101M, 101Y.
[0132] Compositions of processing solutions and each ink used in
this example are as the following. Here, the contents shown below
are indicated by pts. wt.
2 [processing solution] Glycerin 7 pts. wt. Diethylene glycol 5
pts. wt. Acetylenol EH 2.1 pts. wt. (made by Kawaken Fine Chemical
Co., Ltd.) Poly-allylamine 4 pts. wt. (molecular weight: 1500 or
less, mean molecular weight: about 1000) acetic acid 4 pts. wt.
Benzalkonium chloride 0.5 pts. wt. Tri-ethylene glycol mono-butyl
ether 3 pts. wt. Water Remainder [Yellow (Y) ink] C. I. Direct
yellow 86 3 pts. wt. Glycerin 5 pts. wt. Diethylene glycol 5 pts.
wt. Acetylenol EH 1 pts. wt. (made by Kawaken Fine Chemical Co.,
Ltd.) Water Remainder [Magenta (M) ink] C. I. Acid red 3 pts. wt.
Glycerin 5 pts. wt. Diethylene glycol 5 pts. wt. Acetylenol EH 1
pts. wt. (made by Kawaken Fine Chemical Co., Ltd.) Water Remainder
[Cyan (C) ink] C. I. Direct Blue 199 3 pts. wt. Glycerin 5 pts. wt.
Diethylene glycol 5 pts. wt. Acetylenol EH 1 pts. wt. (made by
Kawaken Fine Chemical Co., Ltd.) Water Remainder [Black (Bk) dye
ink] Food Black 2 4 pts. wt. Glycerin 7.5 pts. wt. Diethylene
glycol 7.5 pts. wt. Urea 7.5 pts. wt. Water Remainder
[0133] In the example, the nozzles of each printing head are
arrayed at a concentration of 600 dpi (dots per inch), and further,
operates printing at a concentration of 600 dpi in the direction of
the recording paper conveyance. Thus, the dot concentration of an
image, etc. printed in accordance with this example 600 dpi in both
row and column directions. Further, since the discharging frequency
of each head is 4 kHz, the conveyance speed of the recording paper
is about 170 mm/sec. Moreover, a distance Di (refer to FIG. 5)
between the dye ink head 101Bk and the processing solution head
101S is 40 mm, therefore, it takes about 0.24 sec from discharging
of the black dye ink on a position until discharging of the
processing solution on the position.
[0134] In the above configuration, 30 pl of dye Bk ink is
discharged from the head 101Bk, and then 15 pl of the processing
solution is discharged from the head 101S, to form one black dot.
In this case, since the antecedently discharged dye ink is a poor
permeable ink, it penetrates little into the recording paper and
about 45 pl of the mixed solution is formed when the processing
solution is deposited onto the antecedently landed ink. In this
case, the acetylenol contents (wt. %) of the Bk ink and the
processing solution before mixing are 0% and 2.1% respectively,
while the content (wt. %) of acetylenol, surface active agent of
the mixed solution, becomes 0.7%. Thus, the above mixed solution
becomes a high penetrability ink, which is fixed quickly. Further,
the mixed solution has then about 5.0
(ml/m.sup.2.multidot.msec.sup.1/2) of Ka value and about 33 dyne/cm
of surface active tension.
[0135] When 100% duty printing, what is called "solid printing",
was performed, the fixing time was about 1 second after discharging
of the processing solution.
EXAMPLE 2
[0136] This example is different from the above example 1 in the
point that a pigment ink Bk without dispersing agent is discharged
from the head 101Bk shown in FIG. 5.
[0137] In this example, discharging amount per one nozzle of the
head 101Bk is 30 pl as in the above example 1, and discharging
amount of the processing solution is also 15 pl as in the above.
However, each acetylenol content of the Bk ink and the processing
solution is 0.2% and 1.7%, respectively. Thus, the acetylenol
content becomes 0.7% when they are mixed on the recording paper,
and this mixed solution shows a high penetrability and is fixed
quickly.
[0138] Also in this example, a printing method similar to the above
was employed for fixing time measurement, and similarly, one second
was obtained for the fixing time.
[0139] The above-mentioned pigment Bk ink without dispersing agent
is as the following.
[0140] For a pigment used for this example, a self-dispersion type
pigment is used, to which at least a kind of anionic group is
bonded to carbon black surface directly or via other atomic group,
but for a color material, a self-dispersion type carbon black is
used, to which at least a kind of hydrophilic group is bonded
directly or via other atomic group. This results in eliminating the
need for dispersing agent to disperse carbon black required for
conventional ink. For the use in this example, ionized
self-dispersing type carbon black is desirable, and anionically
electrified one is suitable.
[0141] In the case of anionically electrified carbon black, for
example, --COOM, --SO.sub.3M, --PO.sub.3HM, --PO.sub.3M.sub.2,
SO.sub.2NH.sub.2, --SO.sub.2NHCOR, etc. can be mentioned as a
hydrophilic group bonded to the surface (wherein M in the formulae
represents hydrogen atom, alkaline metal, ammonium or organic
ammonium, and R represents an alkyl group with 1 to 12 carbon
atoms, a phenyl group which is allowed to have substituent, or a
naphtyl group which is allowed to have substituent). In this
example, especially among the above groups, such carbon black is
preferably used, as is bonded with --COOM or --SO.sub.3M on the
surface of the carbon black and is anionically electrified.
[0142] Also, for "M" of the above-mentioned hydrophilic groups, for
example, lithium, sodium, potassium, etc. can be mention as an
alkaline metal, and for organic ammonium, mono-, di- or tri-methyl
ammonium, mono-, di- or tri-ethyl ammonium, mono-, di- or
tri-methanol ammonium, etc. can be mentioned. As a method of
obtaining anionically electrified carbon black, namely, a method of
introducing --COONa onto the surface of carbon black, for example,
such a method can be mentioned as carbon black is treated with
sodium hypochlorite by oxidation, however, it is obvious that the
present invention is not to be restricted by this method.
[0143] Pigment Bk ink has the following composition.
3 [Black Bk pigment ink] Pigment dispersing solution 50 pts. wt.
Glycerin 7 pts. wt. Tri-ethylene glycol 7 pts. wt. Acetylenol 0.2
pts. wt. (made by Kawaken Fine Chemical Co., Ltd.) Water
Remainder
[0144] The above-mentioned pigment dispersing solution is as
follows.
[0145] [Pigment Dispersing Solution]
[0146] At 5.degree. C., 1.58 g anthranilic acid was added into
solution in which 5 g concentrated hydrochloric acid is dissolved
in 5.3 g water. This solution was always kept at 10.degree. C. or
the less, by being stirred in an ice bath, and another solution
dissolving 1.78 g sodium nitrite added to 8.7 g water was added to
that solution. Further, after 15 minutes stirring, 20 g carbon
black, of which oil absorption is 120 ml/100 g DBP and a surface
area is 320 m.sup.2/g, was added to the former solution in a mixed
state. And then, the mixture was stirred for another 15 minutes.
The obtained slurry was filtered by Toyo Filter Paper No. 2 (made
by Advantis, Ltd.), and after the pigment particles were
sufficiently rinsed and dried in an oven at 110.degree. C., water
was added to the pigment for making 10 wt. % pigment aqueous
solution. By this method, a pigment dispersing solution was
obtained as expressed by the formula below, in which anionically
electrified self-dispersed type carbon black bonded to hidrophilic
group via phenyl group is dispersed on the surface. 1
EXAMPLE 3
[0147] In this example, two heads are used with Bk ink, and are
configured to discharge dye ink and pigment ink, respectively. FIG.
7 is a schematic sectional view showing a printing apparatus
relating to this example.
[0148] A head 101Bk1 discharges 15 pl dye Bk ink per each nozzle,
and a head 101Bk2 discharges 15 pl pigment Bk ink per each nozzle.
Also, a processing solution head 101S discharges 15 pl processing
solution per each nozzle. And, these dye Bk ink, pigment Bk ink,
and processing solution contain 0%, 0.2%, and 1.9% acetylenol,
respectively.
[0149] According to the above composition, when a dot of Bk ink is
formed in printing, the above-mentioned dye Bk ink, pigment Bk ink,
and processing solution are made coalescent on the recording paper
103, and as a result, the acetylenol content of the mixed solution
becomes 0.7%, and the mixed solution becomes highly
penetrative.
EXAMPLE 4
[0150] In this example, the order of discharging the pigment ink
and dye ink is reversed compared with the above example 3. Namely,
in FIG. 7, the head 101Bk1 discharges pigment ink, and the head
101BK2 discharges dye ink. In this case also, an effect similar to
that from the above example 3 can be achieved.
EXAMPLE 5
[0151] In this example, one head is provided for Bk ink as shown in
FIG. 5, and this head discharges a mixed ink of dye Bk ink and
pigment Bk ink. The discharging amount of this head is 30 pl
containing 0.1% acetylenol, while 15 pl processing solution is
discharged as in each example described above but 1.9% acetylenol
is contained. Thus, acetylenol content of a mixed solution of the
mixed Bk ink and the processing solution becomes 0.7%
[0152] This mixed Bk ink has the following composition.
4 [Mixed Bk ink] Pigment dispersing solution 25 pts. wt. Food black
2 2 pts. wt. Glycerin 6 pts. wt. Tri-ethylene glycol 5 pts. wt.
Acetylenol EH 0.1 pts. wt. (made by Kawaken Fine Chemical Co., Ltd.
) Water Remainder
[0153] According to this example, an effect similar to that from
the above-described examples 3 and 4 can be achieved.
EXAMPLE 6
[0154] In this example, Bk ink is provided with two heads, one of
which discharges jet 15 pl dye ink per each nozzle and the other
discharges 15 pl pigment ink per each nozzle, respectively, and
processing solution is also provided with two heads, of which each
discharges 8 pl processing solution per each nozzle. By this
configuration, discharging is carried out in order of dye Bk ink,
pigment Bk ink, processing solution, and processing solution and
they form a coalescent solution.
[0155] Here, acetylenol contents of each solution are 0%, 0.2%,
0.2%, and 3.6% in the above discharging order, and as a result, an
acetylenol content of the coalescent solution becomes 0.7%. Thus,
high fixation can be achieved. In addition to this, in this
example, the later the discharging order is, the higher
penetrability the solution has, therefore, it is possible to
coalesce the preceding discharged solution and the following
solution before penetration of the preceding solution, and this
coalesce can make the penetrability of the mixed solution
higher.
FURTHER EXAMPLES
[0156] In each example described above, the compositions of Bk ink
to improve its fixation have been described as preferred
embodiments of the present invention, however, application of the
present invention is not to be restricted by the above. For
example, in a case of mixing processing solutions with color inks
regarding each color ink, or intermixing light and shade inks
regarding a same color, the present invention is applicable
thereto. For example, when color printing is performed by using Y,
M, and C inks, Y-ink, of which an improvement in concentration is
not so much desired, is made as a high permeable ink while other
inks are made as poor permeable inks, and thus, it is thereby
possible to provide the mixture with a predetermined acetylenol
content when they are mixed.
[0157] Moreover, in the above examples 1 and 2, dye ink or pigment
ink was made to be discharged 30 pl from one head per each nozzle,
however, the same effect can be also obtained if two heads
discharge 15 pl of the ink per nozzle respectively.
[0158] Moreover, in the above examples, pigment ink without
dispersing agent has been described, however, it is obvious that
pigment ink with dispersing agent may also be used. Further, each
of the dye ink and the pigment ink may partly contain pigment and
dye of less composition rate to the other, respectively.
[0159] Further, in each example of the above, the configuration may
be such as a high penetrative processing solution is discharged
before Bk ink is further discharged.
[0160] Further, applicability of the present invention is not to be
restricted to a full line type printer as shown in each example of
the above, but the invention is applicable to a serial type printer
as shown in FIG. 8.
[0161] FIG. 8 is a schematic drawing showing the constitution of a
serial type printer 5 relating to an example of the present
invention. Namely, it is obvious that a printing apparatus, wherein
dye ink and pigment ink are mixed on a printing medium before they
are reacted with a processing solution, is applicable not only to
the above-described full line type but also to the serial type
apparatus. Here the same components as shown in FIG. 5 or FIG. 7
are marked with the same codes for omitting the detail description
about them. Further, two Bk ink heads are provided in the
configuration shown in the figure.
[0162] Recording paper 103 as a printing medium is inserted from a
paper feeding part 105 and ejected via printing part 126. In this
example, widely used inexpensive ordinary paper is used as
recording paper 103. In the printing part 126, a carriage 107 is
arranged to mount printing heads 101Bk1, 102Bk2, 101S, 101C, 101M,
and 101Y and move back and forth along a guide rail 109 by means of
a driving force of an unshown motor. The printing head 101Bk1
discharges black pigment ink, and the printing head 102Bk2
discharges black dye ink. The printing heads 101S, 101C, 101M, and
101Y discharge processing solution, cyan ink, magenta ink, yellow
ink, respectively, and are driven in this order to discharge ink or
processing solution on a sheet of the recording paper 103.
Moreover, the black pigment ink is an ink without dispersing
agent.
[0163] To each head, ink or processing solution is supplied from
each tank 108Bk1, 108Bk2, 108S, 108C, 108M and 108Y, respectively.
In discharging state, a driving signal is supplied to an
electro-thermal transducer of heater disposed at each nozzle of
each head, and then thermal energy acts on ink or processing
solution to generate a bubble therein, thereby ink or processing
solution is discharged by the pressure of the bubble. Each head has
64 pieces of discharging portions or nozzles arrayed at 360 DPI in
the direction substantially same direction of conveying direction
of the recording paper 103, that is, the nozzles are arrayed in the
direction perpendicular to the scanning direction of each head.
Here, discharging amount per one nozzle is 23 pl.
[0164] In the above arrangement, each head is arranged at 1/2 inch
intervals, and has a printing concentration of 720 dpi in the
scanning direction and a discharging frequency of 7.2 kHz.
[0165] Further, in each example of the above, discharging system of
each head makes use of thermal energy to discharge ink or
processing solution, however, the present invention does not
restrict this applicability but, for example, a system using
piezo-element may be applicable.
[0166] Furthermore, in each example of the above, it is assumed
that basically, the later the discharging order is, the higher
penetrability ink or processing solution has, therefore, the
precedent discharging ink penetrates little into recording paper
before the following ink is discharged. However, for example, when
a high penetrability ink is adopted for Y-ink as described above
and color printing is performed by discharging this ink
precedently, Y-ink penetrates into the paper to some extent before
the following ink, etc. are discharged. Therefore, in such a case,
a discharging rate and discharging intervals of Y-ink discharged at
the same time have only to be determined so that acetylenol content
becomes a percentage showing the predetermined high penetrability
described above to the total solution volume at the time when the
succeeding ink is discharged and mixed.
[0167] As being apparent from the above descriptions, according to
the present invention, a plurality of different droplets of ink,
processing solution, etc. coalesce into one droplet and its
critical micell concentration, surface tension, and Ka value, which
represent the penetrability of the droplet, becomes a predetermined
value of high penetrability or higher, therefore, the penetration
is accelerated as a droplet after coalescence even if not all the
droplets have high penetrability.
[0168] Thus, even if low penetrative ink, etc. are used to improve
OD value and suppress feathering, they shows a high penetrability
as a coalesced one and fixation is not inhibited.
[0169] Consequently, it is possible to achieve high fixation
without using a means like a heater, etc. and improve printing
quality.
[0170] The present invention has been described in detail with
respect to various embodiments, and it will be apparent from the
foregoing to those skilled in the art that changes and
modifications may be made without departing from the invention in
its broader aspects, and it is the intention, therefore, in the
appended claims to cover all such changes and modifications as fall
within the true spirit of the invention.
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