U.S. patent application number 09/947191 was filed with the patent office on 2002-06-13 for aqueous gel ink-filled ball point pen.
This patent application is currently assigned to MITSUBISHI PENCIL KABUSHIKI KAISHA. Invention is credited to Miyamoto, Masaru.
Application Number | 20020071709 09/947191 |
Document ID | / |
Family ID | 24076942 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020071709 |
Kind Code |
A1 |
Miyamoto, Masaru |
June 13, 2002 |
AQUEOUS GEL INK-FILLED BALL POINT PEN
Abstract
Provided is an aqueous gel ink-filled ball point pen having less
blobbing and capable of drawing stable lines having vivid color and
no uneven written intensity. The aqueous gel ink-filled ball point
pen has a ball of a diameter of 0.6 to 2.0 mm at a tip point with
an aqueous gel ink containing a pigment whose specific gravity is 2
or more and having a viscosity ratio (a value of (viscosity at 10
rpm)/(viscosity at 50 rpm) measured by means of an E type
rotational viscometer) of 3.0 to 5.0, and an ink lay down value
according to JIS Standard S6053 which is controlled to 220 to 800
mg/m.
Inventors: |
Miyamoto, Masaru; (Kanagawa,
JP) |
Correspondence
Address: |
DARBY & DARBY
805 Third Avenue
New York
NY
10022
US
|
Assignee: |
MITSUBISHI PENCIL KABUSHIKI
KAISHA
Tokyo
JP
|
Family ID: |
24076942 |
Appl. No.: |
09/947191 |
Filed: |
September 5, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09947191 |
Sep 5, 2001 |
|
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|
09521492 |
Mar 9, 2000 |
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Current U.S.
Class: |
401/215 |
Current CPC
Class: |
C09D 11/18 20130101 |
Class at
Publication: |
401/215 |
International
Class: |
B43K 007/10 |
Claims
What is claimed:
1. An aqueous gel ink-filled ball point pen which has a ball of a
diameter of 0.6 to 2.0 mm at the tip point thereof and is charged
with an aqueous gel ink comprising a pigment, said pigment having a
specific gravity of 2 or more; said gel ink having a viscosity
ratio of 3.0 to 4.30, wherein said viscosity ratio is measured by
(viscosity at 10 rpm)/(viscosity at 50 rpm) measured by means of an
E type rotational viscometer, and an ink lay down value according
to JIS Standard S6053 of from 220 to 780 mg/100 m.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is directed to aqueous gel ink-filled
ball point pens, more specifically to ball point pens having a ball
of a diameter of 0.6 mm to 2.0 mm, and filled with an ink
containing a special colorant whose specific gravity is 2 or more
and has properties expressed by pseudo-plasticity, non-Newtonian
viscosity or shear thinning viscosity.
[0003] 2. Description of the Prior Art
[0004] A ball point pen is composed of a pen tip comprising a ball
and a tip holder, an ink reservoir and a barrel. In writing with a
ball point pen, the ink flowing out of the inside of the tip with
rotation of the ball is transferred on or penetrated into a
recording material such as paper, whereby letters and lines are
written.
[0005] One advantage of aqueous ink-filled ball point pens is that
the pens use inks having a low viscosity of several mPa's, and
therefore can write at a low writing pressure and impart a good
writing feeling. However, one defect of aqueous ink-filled ball
point pens is a natural outflow of the ink from the point of the
tip, a so-called "point seepage" (hereinafter called a direct flow
phenomenon) or a back-leaking phenomenon in which air flows in from
the tip of the ball point pen to allow the ink to flow out from the
ink reservoir. Ink absorbers comprising a bundle of fibers are used
to prevent these phenomena.
[0006] Another problem with aqueous gel ink-filled ball point pens
is that if the ball point pen is left in a cap-off condition, the
solvent is dried up because of the high vapor pressure of the
solvent, and therefore the pen point is dried to prevent the ink
from flowing out. As a result, the ball point pen becomes incapable
of writing.
[0007] On the other hand, a conventionally known oil based
ink-filled ball point pen uses an ink having a high viscosity of
several thousand mPa's and therefore has the defect that the ball
receives large resistance in rotating when the ink flow out of the
pen tip, resulting in an unfavorable writing feeling. Further, if
less amount of ink flows out of the tip in writing there is a
blobbing phenomenon, unevenness on drawn lines, weak line
intensity, and a high writing pressure is required.
[0008] One method of improving oil based ink-filled ball point pen,
is to use a ball point pen for an aqueous ink having a so-called
medium viscosity, which falls within a middle viscosity region
(several mPa's to several thousand mPa's) ranging between the
viscosities of an aqueous ink and an oil based ink. This is a ball
point pen using a relatively low viscosity aqueous ink having the
characteristic that the viscosity of the ink is lowered by the
rotation of the ball point to allow the ink to flow out smoothly, a
so-called shear thinning viscosity.
[0009] Inks of this type are known as "gel inks", and the property
thereof is shown by expression such as pseudo-plasticity,
non-Newtonian viscosity and the like. However, if the ink has too
strong a gel property, pigments in the ink coagulate and the
flowability of the ink becomes inferior, so that outflow of the ink
from the pen point is deteriorated in writing, and starving and
inferior writing result. On the other hand, if gelation is weak and
the viscosity is low, pigments in the ink are likely to be settled
and that the ink is liable to bring about back flow or direct
flow.
[0010] Further, with gel inks there is a possibility that a special
pigment whose specific gravity is large can be used, although such
a special pigment was not able to be used for conventional
low-viscosity water based inks for a ball point pen. However, the
strength of gel has to be increased when a pigment having a large
specific gravity is used. Accordingly, at present, ink stability,
writing feeling, back flow and direct flow phenomena, and pen
structure exert influence on each other, so that an ideal aqueous
gel ink-filled ball point pen has not yet been obtained.
SUMMARY OF THE INVENTION
[0011] An object of the present invention is to solve the problems
described above and provide a ball point pen having less blobbing
and capable of drawing stable lines having vivid color and no
uneven intensity, wherein the ball point is filled with an ink
using a pigment having a large specific gravity.
[0012] Intensive research by the present inventors has resulted in
the finding that the problems can be solved by adjusting the
relation of the structure of a tip with the strength of gel, and
controlling the lay down value of ink, thus coming to complete the
aqueous gel ink-filled ball point pen of the present invention.
[0013] The aqueous gel ink-filled ball point pen of the present
invention is an ordinary ball point pen having a refill comprising
a pen tip comprising a ball and a tip holder, an ink reservoir and
a coupling for connecting the tip with the reservoir. The lay down
value of the ink according to JIS standard S6053 is controlled to
220 to 800 mg/100 m, preferably 220 to 780 mg/100 m, by selecting
an ink having a suitable viscosity ratio depending on the diameter
of the point of the tip or selecting a suitable tip depending on
the viscosity ratio of the gel ink.
[0014] That is, the aqueous gel ink-filled ball point pen of the
present invention is different from ones obtained by merely
charging conventional ball point pens with a conventional gel ink,
in which the colorant is a pigment whose specific gravity is
small.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 depicts a ballpoint pen of the type well known in the
art, containing a ball 1 and tip 2 housed in a mouthpiece 3. An
aqueous gel ink 7 and ink follower 10 are housed in an ink
reservoir 8 contained in barrel 9. A cap 4 having a clip 6 is
placed over the mouthpiece containing the ball and tip. A joint 5
connects the ink reservoir with the tip. An end plug 11 seals the
ink reservoir.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] The aqueous gel ink-filled ball point pen of the present
invention is obtained by charging a ball point pen having a ball of
a diameter of 0.6 to 2.0 mm at the point of the tip with an aqueous
gel ink, and controlling an ink lay down value (according to JIS
Standard S6053) to 220 to 800mg/100 m, (preferably 220 to 780
mg/100 m). Exemplary aqueous gel inks may also have an ink lay down
value of 380 mg/100 m, 550 mg/100 m or 750 mg/100 m.
[0017] The aqueous gel ink of the mention has a viscosity ratio of
3.0 to 5.0, preferably 3.0 to 4.30, wherein the viscosity ratio
represents a value of (viscosity at 10 rpm)/(viscosity at 50 rpm)
measured by means of an E type rotational viscometer. Exemplary
viscosity ratios for aqueous gel inks may also have a ratio of
3.80.
[0018] When the viscosity ratio is smaller than 3, the settling of
a pigment is likely to occur, and a pigment in accordance with the
present invention having a specific gravity of 2 or more settles at
the tip of a ball point pen resulting in clogging of the tip,
thereby causing poor writing performance. When the viscosity ratio
is larger than 5, a gel becomes so strong as to cause poor
flowability so that ink can not be supplied from the tip.
[0019] The ink lay down value of 220 to 800mg/100 m shows a
characteristic representing the intensity of written lines, wherein
the ink lay down value is obtained from a difference between the
following two weight values: the weight of the ball point pen
measured after writing a line of 400 m on a writing paper by means
of a writing tester, and the weight of the ball point pen measured
after writing further a line of 100 m.
[0020] An ink lay down value of less than 220 mg is too low, and
brings about starving due to a reduction in the intensity and
inferior ball rotation. On the other hand, an ink lay down value of
more than 800 mg is too high, and therefore brings about feathering
and blobbing phenomena and delays drying of the drawn lines on
hands and clothes. Preferred ranges of ink lay down values are 220
to 780 mg/100 m, or 380 to 780 mg/100 m.
[0021] The tip of the aqueous gel ink-filled ball point pen of the
present invention has a ball having a diameter of 0.6 to 2.0 mm.
The structure and the material of the tip shall not specifically be
restricted and are those used for conventional ball point pens. A
sintered hard alloy is usually used for a ball material, and
ceramics, resins and rubber are included as well. Stainless steel,
bronze and German silver are usually used for a holder material,
and resin-molded articles can be used as well.
[0022] Inks containing colorants, pseudo -plasticizers and aqueous
medium components are used as the gel ink for the ball point pen of
the present invention.
[0023] The aqueous medium component represents water and polar
liquid medium other than water and includes, for example, water or
water soluble organic solvents. Specific examples thereof include
alkylene glycols such as ethylene glycol, triethylene glycol,
tetraethylene glycol, dipropylene glycol, 1,2-propanediol,
1,3-propanediol, 1,2-butanediol, 2,3-butanediol, 1,3-butanediol,
1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 2,5-hexanediol,
3-methyl-1,3-butanediol and 2-methylpentane-2,4-diol, polyalkylene
glycols such as polyethylene glycol and polypropylene glycol,
triols such as 3-methylpentane-1,3,5-triol and 1,2,3-hexanetriol,
glycerols such as glycerol, diglycerol and triglycerol, lower alkyl
ethers of glycols such as ethylene glycol monomethyl ether,
ethylene glycol monoethyl ether, diethylene glycol monomethyl
ether, diethylene glycol monoethyl ether and diethylene glycol
mono-n-butyl ether, thiodiethanol, N-methyl-2-pyrrolidone and
1,3-dimethyl-2-imidazolidinone.
[0024] Usually, the content thereof is preferably 10 to 90%, more
preferably 30 to 80%, by weight based on the total amount of the
ink.
[0025] The pseudo-plasticizer includes natural resins such as
xanthan gum, tamarind gum, carrageenan gum, tragacanth gum, locust
bean gum, gum arabic, guar gum, tara gum, curdlan, pectin, agar,
gelatin and mannan which are composed of monosaccharides and
polysaccharides such as glucose, mannose, galactose, rhamnose and
glucuronates, celluloses such as methyl cellulose, ethyl cellulose
and carboxymethyl cellulose, acrylic and urethane synthetic
polymers, and inorganic natural or semi-synthetic products such as
smectite and montmorillonite.
[0026] Pigments used for the colorant shall not specifically be
restricted, and optional ones selected from inorganic and organic
pigments which have so far conventionally been used for aqueous
pigment ink compositions can be used. Pigments whose specific
gravity is 2 or more include pigments comprising metal powders or
metal foils such as aluminum, bronze, gold, silver and copper,
titanium oxide, black titanium oxide, titanium yellow, mica coated
with titanium oxide, titanium nitride, iron oxides such as red iron
oxide and black iron oxide, cobalt oxide, cobalt blue, molybdenum
white, molybdenum red, ultramarine blue, white lead, chrome yellow
and vermilion. Any one or a plurality of these pigments can be used
according to necessity. A representative example of these pigments
is titanium oxide pigment, which has a specific gravity of about 4
and has an excellent covering property, so that an ink containing
it can provide lines in which pigments develop their own colors
without being affected by the ground color of a recording material
(i.e., writing paper).
[0027] Aluminum pigment and mica coated with titanium oxide each
have a specific gravity of about 3 and exhibit a brightening
property. An ink containing them can provide lines which have a
metallic tone.
[0028] The colorants of the present invention are not only composed
of pigments having a specific gravity of 2 or more but may also use
colorants whose specific gravity is smaller than 2 according to
necessity. The colorants whose specific gravity is smaller than 2
are as follows.
[0029] The inorganic pigments include, for example, carbon black,
ultramarine, and the organic pigments include, for example, azo
lakes, insoluble azo pigments, chelate azo pigments, phthalocyanine
pigments, perylene and perinone pigments, anthraquinone pigments,
quinacridone pigments, dye lakes, nitro pigments and nitroso
pigments.
[0030] To be specific, there can be used phthalocyanine blue (C. I.
74160), phthalocyanine green (C. I. 74260), Hansa yellow 3 G (C. I.
11670), disazo yellow GR (C. I. 21100), Permanent red 4R (C. I.
12335), Brilliant carmine 6B (C. I. 15850) and quinacridone red (C.
I. 46500).
[0031] These pigments may be used alone or in combination of two or
more kinds thereof. The content thereof is selected usually from a
range of 1 to 50% by weight, preferably 5 to 30% by weight based on
the weight of the whole ink. When the content of the pigment is
less than 1% by weight, the intensity of the drawn lines becomes
weak. On the other hand, when it exceeds 50% by weight, the ink
becomes unstable as time goes on, and therefore it is not
preferred.
[0032] Nonionic and anionic surfactants and water soluble polymers
are used as a dispersant which is adsorbed on the surface of a
pigment particle to disperse the pigment in water. The water
soluble polymers are preferably used.
[0033] The nonionic surfactants include polyoxyalkylene higher
fatty acid esters, higher fatty acid partial esters of polyhydric
alcohols and higher fatty acid esters of saccharide. To be
specific, they include glycerin fatty acid esters, polyglycerin
fatty acid esters, propylene glycol fatty acid esters,
pentaerythritol fatty acid esters, polyoxyethylene sorbitan fatty
acid esters, polyoxyethylene sorbitol fatty acid esters,
polyoxyethylene glycerin fatty acid esters, polyethylene glycol
fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene
phytosterol, polyoxyethylene polyoxypropylene alkyl ethers,
polyoxyethylene alkylphenyl ethers, polyoxyethylene castor oil,
polyoxyethylene lanolin, polyoxyethylene lanolin alcohols,
polyoxyethylene alkylamines, polyoxyethylene fatty acid amides and
polyoxyethylene alkylphenyl formaldehyde condensation products.
[0034] The anionic surfactants include alkylated sulfonates of
higher fatty acid amides and alkylarylsulfonates. To be specific,
they include alkylsulfates, polyoxyethylene alkyl ether sulfates,
N-acylamino acid salts, N-acylmethyltaurine salts, polyoxyethylene
alkyl ether acetates, alkylphosphates and polyoxyethylene alkyl
ether phosphates.
[0035] The water soluble polymers include polyacrylic acids,
acrylic acid copolymers and a maleic acid resin. Useful water
soluble polymers are obtained by turning resins such as an acrylic
acid resin, a styrene acrylic resin and a styrene maleic acid resin
into water soluble salt forms. Sodium and potassium are typical as
alkali metals for forming the salts, and typical as amines for
forming the salts are aliphatic primary to tertiary amines such as
mono-, di- or tri-methylamine, alcoholamines such as mono-, di-or
tri-propanolamine, methylethanolamine, methylpropanolamine and
dimethylethanolamine, ammonia, morpholine, and
N-methylmorpholine.
[0036] The content of the dispersant is 0.5 to 5.0% by weight based
on the weight of the ink and 5 to 50% by weight based on the weight
of the pigment.
[0037] Any water soluble dye of direct dyes, acid dyes, food dyes
and basic dyes can be used as a dye of the colorant.
[0038] Examples of the direct dyes shall be described below. C. I.
Direct Black 17, ditto 19, ditto 22, ditto 32, ditto 38, ditto 51
and ditto 71, C. I. Direct Yellow 4, ditto 26, ditto 44 and ditto
50, C. I. Direct Red 1, ditto 4, ditto 23, ditto 31, ditto 37,
ditto 39, ditto 75, ditto 80, ditto 81, ditto 83, ditto 225, ditto
226 and ditto 227, and C. I. Direct Blue 1, ditto 15, ditto 71,
ditto 86, ditto 106 and ditto 119.
[0039] Further, examples of the acid dyes shall be described
below.
[0040] C. I. Acid Black 1, ditto 2, ditto 24, ditto 26, ditto 31,
ditto 52, ditto 107, ditto 109, ditto 110, ditto 119 and ditto 154,
C. I. Acid Yellow 7, ditto 17, ditto 19, ditto 23, ditto 25, ditto
29, ditto 38, ditto 42, ditto 49, ditto 61, ditto 72, ditto 78,
ditto 110, ditto 127, ditto 135, ditto 141 and ditto 142, C. I.
Acid Red 8, ditto 9, ditto 14, ditto 18, ditto 26, ditto 27, ditto
35, ditto 37, ditto 51, ditto 52, ditto 57, ditto 82, ditto 87,
ditto 92, ditto 94, ditto 111, ditto 129, ditto 131, ditto 138,
ditto 186, ditto 249, ditto 254, ditto 265 and ditto 276, C. I.
Acid Violet 15 and ditto 17, C. I. Acid Blue 1, ditto 7, ditto 9,
ditto 15, ditto 22, ditto 23, ditto 25, ditto 40, ditto 41, ditto
43, ditto 62, ditto 78, ditto 83, ditto 90, ditto 93, ditto 103,
ditto 112, ditto 113 and ditto 158, and C. I. Acid Green 3, ditto
9, ditto 16, ditto 25 and ditto 27.
[0041] Most of the food dyes are included in the direct dyes or the
acid dyes, and one example of what are not included therein
includes C. I. Food Yellow 3.
[0042] Next, examples of the basic dyes shall be described
below.
[0043] C. I. Basic Yellow 1, ditto 2 and ditto 21, C. I. Basic
Orange 2, ditto 14 and ditto 32, C. I. Basic Red 1, ditto 2, ditto
9 and ditto 14, C. I. Basic Violet 1, ditto 3 and ditto 7, C. I.
Basic green 4, C. I. Basic Brown 12, and C. I. Basic Black 2 and
ditto 8.
[0044] These colorants may each be used alone or in combination of
two or more kinds thereof.
[0045] Further, lubricants, rust preventives, antiseptics and pH
controllers can be used if necessary.
[0046] The ink used for the ball point pen of the present invention
can be produced, for example, by the following three steps.
[0047] 1. Preparation of pigment-dispersed material (toner).
[0048] A pigment, a dispersant, a solvent, additives and water are
sufficiently dispersed by means of a dispersing machine such as a
beads mill and a ball mill and then centrifuged to remove coarse
matters, whereby a toner is obtained.
[0049] 2. Preparation of pseudo-plasticizer base (gel base).
[0050] A pseudo -plasticizer is gradually added to a prescribed
amount of water, and stirring is continued to completely dissolve
it in water. Then, a base such as monoethanolamine or
triethanolamine is added to control pH to 6 to 9, whereby a gel
base is prepared.
[0051] 3. Preparation of ink.
[0052] The gel base and the solvent are weighed and then
sufficiently mixed by means of a stirrer.
[0053] Then, the toner is added thereto, and further stirring is
continued until the gelled matter is homogeneously dissolved, and
then foreign matters are removed by a filter, whereby an aqueous
gel ink is obtained.
EXAMPLES
[0054] The present invention shall be explained in further detail
with reference to examples.
[0055] The physical properties of the aqueous gel inks used for the
ball point pens in the examples and the comparative examples were
determined by the following methods.
[0056] Viscosity:
[0057] Measured at a temperature of 25.degree. C. by means of an E
type viscometer.
[0058] Viscosity ratio:
[0059] Viscosities were measured at rotating speeds of 10 rpm and
50 rpm (25.degree. C.) by means of the E type viscometer, and the
viscosity ratio was obtained from the following equation:
Viscosity ratio=(viscosity at rotating speed of 10 rpm)/(viscosity
at rotating speed of 50 rpm)
[0060] Ink lay down:
[0061] The weight (W.sub.1) of the ball point pen was measured
before writing, and then the weight (W.sub.2) of the ball point pen
was measured after writing a line of 100 m on writing paper by
means of a writing test machine (Minitech). The ink lay down was
calculated from the following equation:
Ink lay down=W.sub.1-W.sub.2
[0062] The ball point pens prepared in the examples and the
comparative examples were evaluated by the following methods.
[0063] Writing condition:
[0064] The ball point pens were used for writing by means of a
writing test machine, and the flow conditions of the inks were
evaluated according to the following criteria:
[0065] .circleincircle. Particularly good
[0066] .smallcircle. Good
[0067] X Starved
[0068] Drawn line condition:
[0069] The ball point pens were used for writing by means of a
writing test machine, and the drawn line conditions were evaluated
according to the following criteria:
[0070] .circleincircle. Particularly good
[0071] .smallcircle. Good
[0072] X Pale
[0073] Blobbing prevention:
[0074] After writing under the conditions of a speed of 4.5
m/minute, an angle of 600 and a load of 100 g by means of a writing
test machine, an ink amount adhered to the tip holder and surplus
ink spots fallen during drawing the line were observed and
evaluated according to the following criteria:
[0075] .circleincircle. Scarcely found
[0076] .smallcircle. Slightly found
[0077] .DELTA. Little found
[0078] X Much found
[0079] Drawn line dryability:
[0080] "Spiral" was drawn on writing paper in an air-conditioned
room controlled at a temperature of 25.degree. C. and a humidity of
65%, and after 10 seconds, the spiral was rubbed with a commercial
cotton swab to observe and evaluate stain caused by the ink
according to the following criteria:
[0081] .circleincircle. No stain found and particularly good
[0082] .smallcircle. Little stain found
[0083] X Stained
[0084] The aqueous gel inks used in the examples and the
comparative examples were prepared in the following manner.
[0085] Ink A
[0086] A gel ink A was prepared with the following composition:
1 Titanium oxide 20.0 parts by weight Acrylic resin (molecular
weight: 10,000) 2.0 part by weight Aminomethylpropanol 1.0 part by
weight Alkylphosphates 1.0 part by weight Xanthan gum 0.4 part by
weight Propylene glycol 15.0 parts by weight Deionized water 60.6
parts by weight
[0087] An aqueous gel ink having a viscosity ratio of 3.80 was
obtained.
[0088] Ink B
[0089] A gel ink B was prepared in the following composition.
2 Aluminum powder 10.0 parts by weight Acrylic resin (molecular
weight: 5,000) 1.5 parts by weight Aminomethylpropanol 0.7 part by
weight Alkylphosphates 1.0 part by weight Carboxymethyl cellulose
0.6 part by weight Glycerin 5.0 parts by weight Propylene glycol
20.0 parts by weight Deionized water 61.2 parts by weight
[0090] A water base gel ink having a viscosity ratio of 1.40 was
obtained.
[0091] Ink C
[0092] A gel ink C was prepared having the following
composition:
3 Titanium oxide 25.0 parts by weight Acrylic resin (molecular
weight: 10,000) 2.0 parts by weight Triethanolamine 1.0 part by
weight Alkylphosphates 0.8 part by weight Xanthan gum 0.6 part by
weight Glycerin 15.0 parts by weight Deionized water 55.6 parts by
weight
[0093] An aqueous gel ink having a viscosity of 4.30 was
obtained.
EXAMPLE 1
[0094] The holder of a ball point pen ("Signo UM-100" manufactured
by Mitsubishi Pencil K.K. ) was used to charge a refill comprising
a polypropylene -made ink reservoir having an inner diameter of 3.8
mm and a length of 113 mm and a stainless steel-made tip (ball made
of a sintered hard alloy and having a diameter of 0.7 mm) with the
ink A described above. A follower used for "Signo UM-100 " was
filled into the ink rear end, whereby an aqueous gel ink-filled
ball point pen of the present invention was prepared.
[0095] The ink lay down value was 380 mg. The test results of the
writing condition, the drawn line condition, the drawn line
dryability and blobbing are shown in Table 1.
[0096] The test results are shown in Table 1.
EXAMPLE 2
[0097] An aqueous gel ink-filled ball point pen was prepared in the
same manner as in Example 1, except that a tip comprising a ball
made of a sintered hard alloy and having a diameter of 1.0 mm was
used.
EXAMPLES 3 and 4
[0098] The holder of a ball point pen ("Signo UM-100" manufactured
by Mitsubishi Pencil K.K.) was used to charge a refill comprising a
polypropylene-made ink reservoir having an inner diameter of 3.8 mm
and a length of 113 mm and a stainless steel-made tip (ball made of
a sintered hard alloy and having a diameter of 1.4 or 2.1 mm) with
the ink A (Example 3) or ink C (Example 4) respectively. A follower
used for "Signo UM-100" was filled into the ink rear end, whereby
an aqueous gel ink-filled ball point pen was prepared.
[0099] The test results are shown in Table 1.
Comparative Example 1
[0100] The holder of the ball point pen ("Signo UM-100"
manufactured by Mitsubishi Pencil K. K. ) was used to charge a
refill comprising a polypropylene-made ink reservoir having an
inner diameter of 3.8 mm and a length of 113 mm and a stainless
steel-made tip (ball made of a sintered hard alloy and having a
diameter of 1.0 mm) with the ink B described above. A follower used
for "Signo UM-100" was filled into the ink rear end, whereby an
aqueous gel ink-filled ball point pen was prepared.
[0101] The test results are shown in Table 1.
Comparative Example 2
[0102] An aqueous gel ink-filled ball point pen was prepared in the
same manner as in comparative Example 1, except that a tip
comprising a ball made of a sintered hard alloy and having a
diameter of 0.7 mm was used.
[0103] The test results are shown in Table 1.
Comparative Example 3
[0104] An aqueous gel ink-filled ball point pen was prepared in the
same manner as in Example 1, except that a tip comprising a ball
made of a sintered hard alloy and having a diameter of 0.5 mm was
used.
[0105] The test results are shown in Table 1.
Comparative Example 4
[0106] An aqueous gel ink-filled ball point pen was prepared in the
same manner as in Example 1, except that a tip comprising a ball
made of a sintered hard alloy and having a diameter of 2.1 mm was
used.
[0107] The test results are shown in Table 1.
4 TABLE 1 Example Comparative Example 1 2 3 4 1 2 3 4 Ink: kind A A
A C B B A A Ink: viscosity 3.80 3.80 3.80 4.30 1.40 1.40 3.80 3.80
ratio Diameter 0.7 1.0 1.4 2.0 1.0 0.7 0.5 2.1 (mm) of ball in tip
Ink lay down 380 550 750 780 446 250 180 900 value (mg/100 m)
Writing .circleincircle. .largecircle. .circleincircle.
.circleincircle. X X X X condition Drawn line .circleincircle.
.largecircle. .largecircle. .largecircle. X X X X condition
Blobbing .largecircle. .circleincircle. .largecircle. .DELTA. X X
.largecircle. X Drawn line .largecircle. .circleincircle.
.largecircle. .largecircle. X X .largecircle. X dryability Writing
condition: .circleincircle. particularly good; .largecircle. good;
X starved Drawn line condition: .circleincircle. particularly good;
.largecircle. good; X pale Blobbing: .circleincircle. scarcely
found; .largecircle. slightly found; .DELTA. little found; X much
found
[0108] Drawn line dryability: .circleincircle. no stain found and
particularly good; .smallcircle. little stain found; X stained.
[0109] As apparent from Table 1, the lay down value of the ink is
controlled to the claimed range by combining an ink having a
claimed viscosity ratio with a diameter of the point of the tip,
and the ink performances in all the Examples of the invention are
good.
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