U.S. patent application number 11/806294 was filed with the patent office on 2007-12-06 for cleaning blade member.
This patent application is currently assigned to SYNZTEC CO., LTD.. Invention is credited to Shuhei Noda.
Application Number | 20070277650 11/806294 |
Document ID | / |
Family ID | 38788584 |
Filed Date | 2007-12-06 |
United States Patent
Application |
20070277650 |
Kind Code |
A1 |
Noda; Shuhei |
December 6, 2007 |
Cleaning blade member
Abstract
An object of the present invention is to provide a cleaning
blade member exhibiting excellent mechanical properties including
wear resistance. The cleaning blade member formed of a rubber-like
elastic material produced through reaction of a long-chain polyol
having a number average molecular weight of 1,500 to 3,800, an
isocyanate, and an isocyanurate derivative having two or more OH
groups, wherein the isocyanurate derivative is employed in an
amount of 0.5 to 15 parts by weight with respect to 100 parts by
weight of the long-chain polyol.
Inventors: |
Noda; Shuhei; (Yokohama-shi,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
SYNZTEC CO., LTD.
Shinagawa-ku
JP
|
Family ID: |
38788584 |
Appl. No.: |
11/806294 |
Filed: |
May 31, 2007 |
Current U.S.
Class: |
76/104.1 |
Current CPC
Class: |
G03G 21/0017 20130101;
G03G 15/161 20130101 |
Class at
Publication: |
76/104.1 |
International
Class: |
B21K 11/00 20060101
B21K011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2006 |
JP |
2006-155288 |
May 28, 2007 |
JP |
2007-140143 |
Claims
1. A cleaning blade member formed of a rubber-like elastic material
produced through reaction of a long-chain polyol having a number
average molecular weight of 1,500 to 3,800, an isocyanate, and an
isocyanurate derivative having two or more OH groups, wherein the
isocyanurate derivative is employed in an amount of 0.5 to 15 parts
by weight with respect to 100 parts by weight of the long-chain
polyol.
2. A cleaning blade member as described in claim 1, wherein the
long-chain polyol has a number average molecular weight of 1,650 to
3,000.
3. A cleaning blade member as described in claim 1, wherein the
isocyanurate derivative is employed as a cross-linking agent or a
chain-extender.
4. A cleaning blade member as described in claim 2, wherein the
isocyanurate derivative is employed as a cross-linking agent or a
chain-extender.
5. A cleaning blade member as described in claim 1, wherein the
long-chain polyol contains a polyester-polyol having an ester
concentration of 6.85.+-.0.25 mmol/g, the ester concentration being
defined by the following relation: ester concentration
(mmol/g)=(amount of ester groups by mole)/(weight of
polyester-polyol).
6. A cleaning blade member as described in claim 5, wherein the
polyester-polyol is formed through dehydration condensation between
at least one diol component selected from among nonanediol and
methyloctanediol and at least one dibasic acid selected from among
adipic acid, sebacic acid, and azelaic acid.
7. A cleaning blade member as described in claim 1, which has a
rubber hardness as stipulated by JIS A of 65 to 85.degree..
8. A cleaning blade member as described in claim 1, which has a
rebound resilience of 40 to 80%, as determined at 25.degree. C.
Description
[0001] The entire disclosure of Japanese Patent Applications Nos.
2006-155288 filed Jun. 2, 2006 and No. 2007-140 filed May 28, 2007
is expressly incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a cleaning blade member
and, more particularly, to a cleaning blade member for removing
toner deposited on a toner image carrier employed in an
electrophotographic process such as a photoconductor or a transfer
belt, on which a toner image is formed and which transfers the
formed image to an image receptor.
[0004] 2. Background Art
[0005] Generally, in an electrophotographic process,
electrophotographic apparatus parts such as an electrophotographic
photoreceptor and a transfer belt are used cyclically and
repeatedly, and toner deposited thereon is removed by means of a
cleaning blade. The cleaning blade, which generally comes into
contact with a photoreceptor over a long period of time, is
required to have excellent wear resistance. Currently, members for
use in such a cleaning blade are made of polyurethane. Polyurethane
is employed because it has excellent wear resistance, exhibits
sufficient mechanical strength without incorporation of additives
such as a reinforcing agent thereinto, and does not stain objects.
However, polyurethane has a drawback in that physical properties
thereof vary with temperature.
[0006] Hitherto, various cleaning blades made of polyurethane have
been developed. Japanese Patent Application Laid-Open (kokai) No.
2001-265190 discloses a cleaning blade made of hardened
polyurethane which exhibits a tensile strength at 50.degree. C. of
12 MPa or more, a tan.delta. peak temperature of 15.degree. C. or
lower, and a hardness of 80.degree. or less. Chipping of the
cleaning blade under high-temperature conditions is effectively
prevented without impairing cleaning performance under
low-temperature conditions. Thus, the cleaning blade exhibits
excellent cleaning performance over a wide temperature range.
[0007] Japanese Patent Application Laid-Open (kokai) No. 9-274416
discloses a blade, for use in electrophotographic apparatuses,
employing a polyurethane sheet which is produced by mixing a
bi-functional polyol having a number average molecular weight of
1,000 to 3,000 and a tri-functional polyol having a number average
molecular weight of 92 to 980, to thereby provide a polyol mixture
having an average functionality of 2.02 to 2.20; mixing the polyol
mixture with a diisocyanate compound having an isocyanate group
content of 5 to 20%, to thereby prepare a prepolymer; adding to the
prepolymer a cross-linking agent in an amount so as to adjust the
OH/NCO ratio (eq.) to 0.90 to 1.05 and a reaction accelerator in an
amount of 0.01 to 1.0 parts by weight with respect to 100 parts by
weight of the prepolymer; and allowing the mixture to react.
[0008] However, wear resistance and other properties of the
aforementioned blades are not satisfactory and, therefore, are to
be further improved.
SUMMARY OF THE INVENTION
[0009] In view of the foregoing, an object of the present invention
is to provide a cleaning blade member exhibiting excellent
mechanical properties including wear resistance.
[0010] Accordingly, in a first mode of the present invention in
order to attain the object, there is provided a cleaning blade
member formed of a rubber-like elastic material produced through
reaction of a long-chain polyol having a number average molecular
weight of 1,500 to 3,800, an isocyanate, and an isocyanurate
derivative having two or more OH groups, wherein the isocyanurate
derivative is employed in an amount of 0.5 to 15 parts by weight
with respect to 100 parts by weight of the long-chain polyol.
[0011] A second mode of the present invention is directed to a
specific embodiment of the cleaning blade member according to the
first mode, wherein the long-chain polyol has a number average
molecular weight of 1,650 to 3,000.
[0012] A third mode of the present invention is directed to a
specific embodiment of the cleaning blade member according to the
first mode, wherein the isocyanurate derivative is employed as a
cross-linking agent or a chain-extender.
[0013] A fourth mode of the present invention is directed to a
specific embodiment of the cleaning blade member according to the
second mode, wherein the isocyanurate derivative is employed as a
cross-linking agent or a chain-extender.
[0014] A fifth mode of the present invention is directed to a
specific embodiment of the cleaning blade member according to the
first mode, wherein the long-chain polyol contains a
polyester-polyol having an ester concentration of 6.85.+-.0.25
mmol/g, the ester concentration being defined by the following
relation:
ester concentration (mmol/g)=(amount of ester groups by
mole)/(weight of polyester-polyol).
[0015] A sixth mode of the present invention is directed to a
specific embodiment of the cleaning blade member according to the
fifth mode, wherein the polyester-polyol is formed through
dehydration condensation between at least one diol component
selected from among nonanediol and methyloctanediol and at least
one dibasic acid selected from among adipic acid, sebacic acid, and
azelaic acid.
[0016] A seventh mode of the present invention is directed to a
specific embodiment of the cleaning blade member according to the
first mode, which has a rubber hardness as stipulated by JIS A of
65 to 850.
[0017] An eighth mode of the present invention is directed to a
specific embodiment of the cleaning blade member according to the
first mode, which has a rebound resilience of 40 to 80%, as
determined at 25.degree. C.
[0018] According to the present invention, there can be provided a
cleaning blade member exhibiting excellent mechanical properties
including wear resistance.
BRIEF DESCRIPTION OF THE DRAWING
[0019] FIG. 1 is a graph showing the results of Test Example 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0020] The cleaning blade member of the present invention is formed
of a rubber-like elastic material produced through reaction of a
long-chain polyol having a number average molecular weight of 1,500
to 3,800, an isocyanate, and an isocyanurate derivative having two
or more OH groups, wherein the isocyanurate derivative is employed
in an amount of 0.5 to 15 parts by weight with respect to 100 parts
by weight of the long-chain polyol. When the isocyanurate
derivative having two or more OH groups is employed in an amount of
0.5 to 15 parts by weight with respect to 100 parts by weight of
the long-chain polyol, and reacted with the long-chain polyol and
the isocyanate, a cleaning blade member exhibiting excellent wear
resistance can be provided. Unless otherwise specified, the unit
"part(s)" denotes "part(s) by weight."
[0021] The long-chain polyol employed in the present invention has
a number average molecular weight of 1,500 to 3,800, preferably
1,650 to 3,000. When the number average molecular weight falls
outside the above range, a cleaning blade member exhibiting
predetermined properties cannot be yielded.
[0022] No particular limitation is imposed on the type of the
long-chain polyol, so long as the molecular weight thereof falls
within the above range. Examples of the long-chain polyol include
polyester-polyols formed through dehydration condensation between a
diol component and a dibasic acid; polycarbonate-polyols formed
through dehydration condensation between a diol and an alkyl
carbonate; caprolactone-derived polyols; and polyether-polyols.
[0023] The long-chain polyol employed in the present invention
preferably contains a polyester-polyol. The polyester-polyol
preferably has an ester concentration of 6.85.+-.0.25 mmol/g, the
ester concentration being defined by the following relation:
ester concentration (mmol/g)=(amount of ester groups by
mole)/(weight of polyester-polyol).
An ester concentration falling within the above range is preferred
for attaining high mechanical strength as well as low
temperature-dependency of rebound resilience and other
properties.
[0024] The polyester-polyol employed in the invention and having an
ester concentration falling within the above range is preferably a
polyester-polyol formed through dehydration condensation between a
diol component and a dibasic acid. However, polyester-polyols other
than those formed through dehydration condensation between a diol
component and a dibasic acid may also be employed so as to attain
the aforementioned properties, so long as the polyester-polyols
have an ester concentration falling within the above range.
[0025] Examples of the polyester-polyol employed in the present
invention include polyester-polyols formed from, in combination, a
diol component such as ethylene glycol, butanediol, hexanediol,
nonanediol, decanediol, 3-methyl-1,5-pentanediol, neopentyl glycol,
2,4-diethyl-1,5-pentanediol, butylethylpropanediol, or
2-methyl-1,8-octanediol, and a dibasic acid such as adipic acid,
sebacic acid, azelaic acid, a dimer acid, or a hydrogenated dimer
acid, with these polyester-polyols having an ester concentration
satisfying the aforementioned conditions. Specific examples include
nonanediol adipate, 2-methyl-1,8-octanediol adipate, decanediol
adipate, hexanediol azelate, nonanediol azelate,
2-methyl-1,8-octanediol azelate, decanediol azelate, butanediol
sebacate, hexanediol sebacate, nonanediol sebacate,
2-methyl-1,8-octanediol sebacate, decanediol sebacate, glycol dimer
acid esters, and glycol hydrogenated dimer acid esters. The diol
components or the dibasic acids may be used singly or in
combination.
[0026] So long as the above conditions are satisfied, a lactone
such as .epsilon.-caprolactone or .delta.-valerolactone may be
polyadded or co-polymerized. In other words, there may also be
employed a random copolymer which has been formed through
copolymerization of a lactone during dehydration condensation
between a diol component and a dibasic acid, or a polyol which has
been formed, for example, polyaddition of a lactone to a
dehydration condensation product. Through employment of a lactone,
rebound resilience at low temperature can further be enhanced.
[0027] Particularly, a polyester-polyol formed through dehydration
condensation between at least one diol component selected from
among nonanediol and methyloctanediol, and at least one dibasic
acid selected from among adipic acid, sebacic acid, and azelaic
acid is preferred from the viewpoint of performance and cost. More
particularly, at least one diol component selected from among
1,9-nonanediol and methyl-1,8-octanediol is preferred. Single use
of 1,9-nonanediol is not preferred, since crystallinity of the
produced polyurethane is excessively high. Therefore, in a
preferred mode, methyl-1,8-octanediol is used singly or in
combination with 1,9-nonanediol. Needless to say, a modified
combination which includes the aforementioned diol component and
dibasic acid as a predominant reactant, and another glycol and
dibasic acid are also preferably employed. As used herein, the diol
"methyl-1,8-octanediol" is an octanediol species having a methyl
group at a position other than 1- and 8-positions, and a typical
example thereof is 2-methyl-1,8-octanediol. However, other
methyl-1,8-octanediol species may also be employed.
[0028] The isocyanate which is reacted with the polyol preferably
has a somewhat non-rigid molecular structure. Examples of such
isocyanates include 4,4'-diphenylmethane diisocyanate (MDI),
2,6-toluene diisocyanate (TDI), 1,6-hexane diisocyanate (HDI),
1,5-naphthalene diisocyanate (NDI), and
3,3-dimethylphenyl-4,4-diisocyanate (TODI). Of these, MDI is
preferred.
[0029] The isocyanurate derivative employed in the present
invention has two or more OH groups, which allow the derivative to
react with an isocyanate and be integrally incorporated into a
polyurethane matrix. The thus-formed polyurethane attains desired
physical properties. Examples of the isocyanurate derivative having
two or more OH groups include tris(2-hydroxyethyl) isocyanurate
having a molecular weight of 261 (Tanac, product of Nissan Chemical
Industries, Ltd.).
[0030] The isocyanurate derivative of the present invention is used
in an amount of 0.5 to 15 parts with respect to 100 parts of the
long-chain polyol. When the amount of isocyanurate derivative is
less than 0.5 parts, the effect of enhancing wear resistance is
insufficient, whereas when the amount is in excess of 15 parts, the
isocyanurate derivative aggregates, thereby failing to form the
rubber-like elastic material.
[0031] The aforementioned isocyanurate derivative having two or
more OH groups is preferably employed as a cross-linking agent or a
chain-extender. Preferably, a cross-linking agent or a
chain-extender other than the isocyanurate derivative is also
employed. The isocyanurate derivative of the present invention may
also serve as a part of the cross-linking agent or the
chain-extender. Since the isocyanurate derivative has high thermal
decomposition temperature, no heat-induced breakage of molecular
chains under friction is considered to occur. Therefore, when the
isocyanurate derivative is employed as a cross-linking agent or a
chain-extender, a cleaning blade member of excellent wear
resistance can be provided.
[0032] Although no particular limitation is imposed on the type of
the cross-linking agent and chain-extender used in combination with
the isocyanurate derivative, a short-chain polyol having a number
average molecular weight of 500 or less is preferably employed.
Examples of the cross-linking agent and chain-extender include
linear-chain glycols having a C2 to C12 main chain such as ethylene
glycol, 1,3-propanediol, and 1,4-butanediol; diols having a
C.ltoreq.12 side chain such as neopentyl glycol, and
3-methyl-1,5-pentanediol; diols having a C.ltoreq.12 unsaturated
group such as 3-allyloxy-1,2-propanediol; C.ltoreq.20 diols having
an aromatic ring such as 1,4-bis(hydroxyethoxy)benzene and p-xylene
glycol; alicyclic diols such as cyclohexanediol and
cyclohexanedimethanol; triols such as trimethylolethane,
trimethylolpropane, and glycerin; and polyols having 4 or more
functionalities, such as pentaerythritol and sorbitol. Needless to
say, these short-chain polyols may be used in combination of two or
more species.
[0033] Of these, bi-functional polyols such as 1,4-butanediol and
1,3-propanediol are particularly preferred, from the viewpoint of
performance and cost.
[0034] The aforementioned long-chain polyol, the isocyanurate
derivative, the cross-linking agent or chain-extender, and the
isocyanate are mixed, and the mixture is allowed to react, to
thereby produce polyurethane. Through modifying the amount (parts)
of isocyanate, the balance of the cross-linking agent or
chain-extender, and other conditions, a cleaning blade member of
more excellent wear resistance can be produced.
[0035] The cleaning blade member according to the present invention
preferably has a rubber hardness as stipulated by JIS A of 65 to
85.degree.. When the hardness is lower than 65.degree., wear
resistance decreases, and detachment of the blade from a support
causing cleaning failure tends to occur, whereas when the hardness
is in excess of 85.degree., the blade member is in contact with a
photoconductor at higher pressure, resulting in wearing of the
photoconductor.
[0036] The cleaning blade member of the invention preferably has a
rebound resilience of 40 to 80%, as determined at 25.degree. C.
When the rebound resilience is lower than 40%, cleaning failure
occurs, whereas when the rebound resilience is in excess of 80%,
anomalous sound (so-called squeaky sound) generates during cleaning
by means of the cleaning blade.
[0037] The rubber-like elastic material employed in the present
invention may be produced through a method typically employed for
producing polyurethane, such as the prepolymer method and the
one-shot method. In the present invention, the prepolymer method is
preferred, since a polyurethane having excellent mechanical
strength and wear resistance can be produced. However, no
particular limitation is imposed on the production method.
[0038] The rubber-like elastic material may be molded through the
centrifugal molding method. When the centrifugal molding method is
employed, the air side of the molded rubber-like elastic material
is preferably brought into contact with a photoconductor.
[0039] The thus-produced polyurethane (rubber-like elastic
material) pieces are subjected to cutting or a similar process, to
thereby form cleaning blade members having predetermined
dimensions. Through bonding each cleaning blade member to a support
member by use of an adhesive or a similar agent, a cleaning blade
product is fabricated.
EXAMPLES
[0040] The present invention will next be described in detail by
way of examples, which should not be construed as limiting the
invention thereto.
Example 1
[0041] A polyol (PCL 220, product of DIC, molecular weight: 2,000)
(100 parts), produced through ring-opening polymerization of
.epsilon.-caprolactam, and 4,4'-diphenylmethane diisocyanate (MDI)
(27 parts) were mixed with stirring at 140.degree. C. for 10
minutes. To the mixture, tris(2-hydroxyethyl) isocyanurate (Tanac,
product of Nissan Chemical Industries, Ltd.) (0.9 parts), which is
an isocyanurate derivative having three OH groups, was added,
followed by stirring for five minutes. Subsequently, 1,4-butanediol
(1,4-BD) (4.2 parts) was further added to the mixture with
stirring. The thus-prepared mixture was cast into a mold which was
maintained at 150.degree. C., and heated for 20 minutes for
reaction, to thereby form a cured rubber-like elastic material. The
formed elastic material was cut into pieces (width: 14 mm), and
each piece was affixed to a metal sheet, to thereby produce a
cleaning blade of Example 1.
Example 2
[0042] The procedure of Example 1 was repeated, except that a
polyol (PCL 230, product of DIC, molecular weight: 3,000), produced
through ring-opening polymerization of .epsilon.-caprolactam, was
used instead of the polyol (PCL 220, product of DIC, molecular
weight: 2,000), produced through ring-opening polymerization of
.epsilon.-caprolactam, and the amounts of Tanac and 1,4-BD were
changed to 5 parts and 4 parts, respectively, to thereby produce a
cleaning blade of Example 2.
Example 3
[0043] The procedure of Example 1 was repeated, except that a
polyol (O-2010, product of Kuraray Co., Ltd., molecular weight:
2,000), produced through dehydration concentration among
nonanediol, methyloctanediol, and adipic acid, was used instead of
the polyol (PCL 220, product of DIC, molecular weight: 2,000),
produced through ring-opening polymerization of
.epsilon.-caprolactam, and the amounts of MDI, Tanac, and, 1,4-BD
were changed to 40 parts, 5.5 parts, and 6.5 parts, respectively,
to thereby produce a cleaning blade of Example
Example 4
[0044] The procedure of Example 3 was repeated, except that a
polyol (PTMG 2000, product of Hodogaya Chemical Co., Ltd.,
molecular weight: 2,000), produced through polymerization of
tetrahydrofuran (THF), was used instead of the polyol (PCL 220,
product of DIC, molecular weight: 2,000), produced through
ring-opening polymerization of .epsilon.-caprolactam, to thereby
produce a cleaning blade of Example 4.
Example 5
[0045] The procedure of Example 3 was repeated, except that
3,3-dimethylphenyl-4,4-diisocyanate (TODI) was used instead of MDI,
to thereby produce a cleaning blade of Example 5.
Example 6
[0046] The procedure of Example 1 was repeated, except that a
polyol (PTMG 1650, product of Hodogaya Chemical Co., Ltd.,
molecular weight: 1,650) was used instead of the polyol (PCL 220,
product of DIC, molecular weight: 2,000), produced through
ring-opening polymerization of .epsilon.-caprolactam, and the
amounts of MDI, Tanac, and, 1,4-BD were changed to 48 parts, 9
parts, and 7 parts, respectively, to thereby produce a cleaning
blade of Example 6.
Comparative Example 1
[0047] The procedure of Example 3 was repeated, except that TMP
(2.8 parts) was used instead of Tanac, and the amount of 1,4-BD was
changed to 6.6 parts, to thereby produce a cleaning blade of
Comparative Example 1.
Comparative Example 2
[0048] The procedure of Example 4 was repeated, except that TMP
(2.8 parts) was used instead of Tanac, to thereby produce a
cleaning blade of Comparative Example 2.
Comparative Example 3
[0049] The procedure of Example 1 was repeated, except that the
amounts of 1,4-BD and Tanac were changed to 4.5 parts and 0.4
parts, respectively, to thereby produce a cleaning blade of
Comparative Example 3.
Comparative Example 4
[0050] The mixing procedure of Example 1 was repeated, except that
MDI (60 parts), Tanac (16.4 parts), and 1,4-BD (6.9 parts) were
used.
Test Example 1
[0051] Test samples were produced from rubber-like elastic
materials produced in the Examples and Comparative Examples.
Rebound resilience of each sample was determined at 25.degree. C.
by means of a Lubke pendulum rebound resilience tester in
accordance with JIS K6255, and rubber hardness (JIS A) of the
sample was determined at 25.degree. C. in accordance with JIS
K6253. Table 1 shows the results.
Test Example 2
Wear Resistance
[0052] Each of the cleaning blades of the Examples and the
Comparative Examples was pressed against a photoconductor, and the
photoconductor was continuously rotated by means of a drive motor
at a circumferential speed of 125 mm/sec for 90 minutes under NN
conditions (23.degree. C., 50%) or LL conditions (10.degree. C.,
30%), while no paper sheet was conveyed. After completion of the
operation, the wear condition of an edge portion of the cleaning
blade was observed under a microscope, and the amount of wear was
microscopically determined. Toner was applied by means of a brush
onto the photoconductor every 15 minutes. The results are shown in
Table 1 and FIG. 1.
<Test Conditions>
[0053] Press conditions; Abutting angle: 25 deg., Pressure: 0.3
N/cm
Photoconductor; OPC (coated with initial lubricant)
Testing time; 90 min
Microscopy conditions;
[0054] Microscope: VH-7000 (KEYENCE Corporation), [0055]
magnification: .times.450
[0056] Measurement points: 5 points per cleaning blade (i.e.,
points 20 mm from the respective ends, points 80 mm from the
respective ends, and the center point)
TABLE-US-00001 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Polyol
PCL 220 PCL 230 0 2010 PTMG 2000 0 2010 PTMG 1650 Ester
concentration 8.5 8.6 6.8 0 6.8 0 Isocyanate MDI MDI MDI MDI TODI
MDI (parts) 27 27 40 40 40 48 Isocyanurate Tanac Tanac Tanac Tanac
Tanac Tanac (parts) 0.9 5 5.5 5.5 5.5 9 diols 1,4-BD 1,4-BD 1,4-BD
1,4-BD 1,4-BD 1,4-BD (parts) 4.2 4 6.5 6.5 6.5 7 Other triols -- --
-- -- -- -- (parts) -- -- -- -- -- -- Hardness JIS A (.degree.) 65
67 72 71 78 74 Rebound resilience (%) at 63 51 54 56 41 42
25.degree. C. Wear width (.mu.m) under NN 3 4 0 5 2 4 conditions
Wear width (.mu.m) under LL 12 9 0 5 2 6 conditions Comp. Ex. 1
Comp. Ex. 2 Comp. Ex. 3 Comp. Ex. 4 Polyol 0 2010 PTMG 2000 PCL 220
PCL 220 Ester concentration 6.8 0 8.5 8.5 Isocyanate MDI MDI MDI
MDI (parts) 40 40 27 60 Isocyanurate -- -- Tanac Tanac (parts) --
-- 0.4 16.4 diols 1,4-BD 1,4-BD 1,4-BD 1,4-BD (parts) 6.6 6.5 4.5
6.9 Other triols TMP TMP -- -- (parts) 2.8 2.8 -- -- Hardness JIS A
(.degree.) 69 70 62 * Rebound resilience (%) at 48 50 67 *
25.degree. C. Wear width (.mu.m) under NN 42 110 62 * conditions
Wear width (.mu.m) under LL 59 115 74 * conditions * The
isocyanurate derivative aggregated in Comparative Example 4,
thereby failing to form the rubber-like elastic material.
[0057] As is clear from Table 1, the cleaning blades of Examples 1
to 6 exhibited a wear width of 5 .mu.m or less under NN conditions
(23.degree. C., 50%) and a wear width of 12 .mu.m or less under LL
conditions (10.degree. C., 30%), showing remarkably excellent wear
resistance. The cleaning blades also exhibited a hardness of 65 to
78.degree. and a rebound resilience of 41 to 63% at 25.degree.
C.
[0058] In contrast, the cleaning blades of Comparative Examples 1
and 2, which had been formed from a composition that does not
include isocyanurate derivative, exhibited excellent hardness and
rebound resilience, but a wide wear width (i.e., very poor wear
resistance) as shown in FIG. 1. The cleaning blade of Comparative
Example 3, which had been formed from a composition containing an
isocyanurate derivative in less than 0.5 parts with respect to 100
parts of a polyol, exhibited excellent hardness and rebound
resilience, but poor wear resistance; i.e., a wear width of 62
.mu.m under NN conditions (23.degree. C., 50%) and a wear width of
74 .mu.m under LL conditions (10.degree. C., 30%). The wear
resistance was not considerably improved, since the amount of
incorporated isocyanurate derivative was small. Furthermore, in
Comparative Example 4, an isocyanurate derivative was used in
excess of 15 parts with respect to 100 parts of a polyol. Thus, the
isocyanurate derivative aggregated, thereby failing to form the
rubber-like elastic material. As described hereinabove, the
cleaning blade member of the present invention, which is formed
from a long-chain polyol having a number average molecular weight
of 1,500 to 3,800 (100 parts), an isocyanurate derivative having
two or more OH groups (0.5 to 15 parts), and an isocyanate, has
been proven to exhibit excellent wear resistance.
* * * * *