Claims
- 1. A toner composition comprising a polyester resin having an OHV/AV value of 1.2 or more as a major component of a binder resin wherein AV is an acid value of said polyester and OHV is a hydroxyl value thereof and hydrophobic silica having a degree of hydrophobic property of not less than 80 said degree being determined by a methanol titration test, and a pH value of 5.5 to 8 when 4% by weight of said hydrophobic silica is dispersed in a water-methanol solution (1:1), said resulting toner composition showing substantially improved charge retention properties under conditions of high temperature and high humidity.
- 2. A toner composition according to claim 1, wherein said hydrophobic silica is obtained by a treatment with an organic silicon compound having a trialkyl group.
- 3. A toner composition according to claim 1, wherein said organic silicon compound is selected from at least one member of the group consisting of hexamethyldisilazane, trimethylchlorosilane and polydimethylsiloxane.
- 4. A toner composition according to claim 1, wherein a chemical structure of said toner composition comprising said hydrophobic silica is selected from at least one of the formulas: ##STR8##
- 5. A toner composition according to claim 1 wherein an addition amount of said hydrophobic silica is 0.01 to 1.5 parts by weight to 100 parts by weight of said toner.
- 6. A toner composition according to claim 5, wherein said hydrophobic silica is contained in an amount of 0.1 to 1.0 parts by weight per 100 parts by weight of said toner.
- 7. A toner composition according to claim 6, wherein said hydrophobic silica is contained in an amount of 0.1 to 0.5 parts by weight per 100 parts by weight of said toner.
- 8. A toner composition according to claim 6, wherein said hydrophobic silica is contained in an amount of 0.2 to 1.0 parts by weight per 100 parts by weight of said toner.
- 9. A toner composition according to claim 1 wherein said polyester resin is prepared by co-condensation polymerization of:
- (1) a diol component represented by the formula: ##STR9## wherein R represents an ethylene or propylene group, x and y each are an integer of 1 or more, and the average value of x+y is 2 to 7;
- (2) a dihydric carboxylic acid, an anhydride thereof or a lower alkyl ester thereof; and
- (3) a trihydric or higher carboxylic acid, an anhydride thereof or a lower alkyl ester thereof; or a trihydric or higher polyhydric alcohol.
- 10. A toner composition according to claim 9 wherein said diol component is selected from the group consisting of polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (3.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene(2.0)-2,2-bis (4-hydroxyphenyl)propane, polyoxypropylene(2.0)-polyoxyethylene (2.0)-2,2-bis(4-hydroxyphenyl)propane and polyoxypropylene(6)-2,2-bis(4-hydroxyphenhyl)propane; said dihydric carboxylic acid is selected from the group consisting of maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, n-butylsuccinic acid, n-butenylsuccinic acid, isobutylsuccinic acid, isobutenylsuccinic acid, n-octylsuccinic acid, n-octenylsuccinic acid, n-dodecylsuccinic acid, n-dodecenylsuccinic acid, isododecylsuccinic acid, isododecenylsuccinic acid and tetrapropenylsuccinic acid; said trihydric or higher polyhydric alcohol is selected from the group consisting of pentaerythritol, trimethylolethane and trimethylolpropane; and said trihydric or higher polyhydric carboxylic acid is 1,2,4-benzenetricarboxylic acid.
- 11. A toner composition according to claim 1 wherein said polyester resin is prepared by co-condensation polymerization of:
- (1) a diol component represented by the formula: ##STR10## wherein R represents an ethylene or propylene group, x and y each are an integer of 1 or more, and the average value of x+y is 2 to 7;
- (2) a dihydric carboxylic acid containing an alkyl or alkenyl succinic acid in an amount of 5 to 50 mol % in total carboxylic acid components, an anhydride thereof or a lower alkyl ester thereof; and
- (3) a trihydric or higher polyhydric carboxylic acid, an acid anhydride thereof or a lower alkyl ester thereof; or a trihydric or higher polyhydric alcohol.
- 12. A toner composition according to claim 11 wherein said diol component is selected from the group consisting of polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (3.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (2.0)-polyoxyethylene (2.0)-2,2-bis(4-hydroxyphenyl)propane and polyoxypropylene (6)-2,2-bis(4-hydroxyphenyl)propane; said dihydric carboxylic acid is selected from the group consisting of maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, n-butylsuccinic acid, n-butenylsuccinic acid, isobutylsuccinic acid, isobutenylsuccinic acid, n-octylsuccinic acid, n-octenylsuccinic acid, n-dodecylsuccinic acid, n-dodecenylsuccinic acid, isododecylsuccinic acid, isododecenylsuccinic acid and tetrapropenylsuccinic acid; said trihydric or higher polyhydric alcohol is selected from the group consisting of pentaerythritol, trimethylolethane and trimethylolpropane; and said trihydric or higher polyhydric carboxylic acid is 1,2,4-benzenetricarboxylic acid.
- 13. A toner composition according to claim 1, wherein said hydrophobic silica has a degree of hydrophobic property of 80 to 110.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2-150389 |
Jun 1990 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 07/708,715 filed on May 31, 1991, now abandoned.
US Referenced Citations (5)
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0270063 |
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58-11954 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
708715 |
May 1991 |
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