US4645729A
Expired / Lapsed
US
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Method for preventing offset in electrophotography
Assignee: Kyocera Mita Industrial Co Ltd
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Filing: 1985-09-26
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Granted: 1987-02-24
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Expires: 2005-09-26
Abstract
Abstract A charged image on a photosensitive layer is developed with a toner containing a releasing agent and a hydroxycarboxylic acid complex salt to form a toner image. The toner image is then transferred to a receptor sheet and fixed to it. The use of a toner containing a specific hydroxycarboxylic acid complex salt brings about a marked advantage of widening a non-offset region to a higher temperature without impairing the antiblocking property, flowability and heat resistance of the toner.
Inventors
- 👤 Nobuyasu Honda
- 👤 Masanori Fujii
- 👤 Masahiko Kubo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:05
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/09783
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
144 words
In an electrophotographic process, including the steps of developing a charged image on a photosensitive layer with a chargeable toner to form a toner image, transferring the toner image from the photosensitive layer to a receptor sheet, and fixing the toner image to the receptor sheet, the improvement which comprises using as the chargeable toner a toner comprising (i) a fixing resin medium which is a copolymer of an aromatic vinyl compound and an ethylenically unsaturated carboxylic acid ester, (ii) 0.5 to 7% by weight, based on the weight of the toner, of a hydroxycarboxylic acid complex salt, and (iii) 1 to 25% by weight, based on the weight of the toner, of a releasing agent, and heat-fixing the toner image by contacting it with a hot roller, whereby the non-offset region is widened on the high temperature side such that offset is prevented.
Claim 2
Dependent Claim
144 words
In an electrophotographic process, including the steps of developing a charged image on a photosensitive layer with a chargeable toner to form a toner image, transferring the toner image from the photosensitive layer to a receptor sheet, and fixing the toner image to the receptor sheet, the improvement which comprises using as the chargeable toner a toner comprising (i) a fixing resin medium which is a copolymer of an aromatic vinyl compound and an ethylenically unsaturated carboxylic acid ester, (ii) 0.5 to 7% by weight, based on the weight of the toner, of a hydroxycarboxylic acid complex salt, and (iii) 1 to 25% by weight, based on the weight of the toner, of a releasing agent, and heat-fixing the toner image by contacting it with a hot roller, whereby the non-offset region is widened on the high temperature side such that offset is prevented.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein the toner contains 0.5 to 6.6% by weight of the hydroxycarboxylic acid complex salt and 1 to 20% by weight of the releasing agent.
Claim 4
Dependent Claim
70 words
The method of claim 1 or 2 wherein the hydroyxcarboxylic acid complex salt is a compound represented by the following general formula ##STR7## wherein R 1 and R 2 represent a residue of a hydroxycarboxylic acid, the hydroxyl group and the carboxyl group are bonded to the carbon atoms adjacent to R 1 to R 2 , and M is a divalent transition metal, particulary iron, cobalt, nickel or chromium.
Claim 5
Dependent Claim
19 words
The method of claim 3 wherein the hydroxycarboxylic acid component of said complex salt is an aromatic hydroxycarboxylic acid.
Claim 6
Dependent Claim
14 words
The method of claim 4 wherein the hydroxycarboxylic acid complex salt is cobalt 2-hydroxy-3-naphthoate.
Claim 7
Dependent Claim
63 words
The method of claim 1 wherein the aromatic vinyl compound is represented by the following formula ##STR8## wherein R 1 represents a hydrogen atom, a lower (C 4 or less) alkyl group or a halogen atom, R 2 represents a substituent such as a lower alkyl group or a halogen atom, and n is an integer of not more than 2 including zero.
Claim 8
Dependent Claim
44 words
The method of claim 1 wherein the ethylenically unsaturated carboxylic acid ester is represented by the following formula ##STR9## wherein R 3 represents a hydrogen atom or a lower alkyl group, and R 4 is an alkyl group having up to 18 carbon atoms.
Claim 9
Dependent Claim
19 words
The method of claim 1 wherein the hot roller has a fixing temperature of from 160° to 200° C.
Claim 10
Dependent Claim
46 words
The method of claim 1 wherein the toner comprises 1 to 3 parts by weight, based on the weight of the toner, of the hydroxycarboxylic acid's complex salt and from 3 to 15% by weight, based on the weight of the toner, of the releasing agent.
Claim 11
Dependent Claim
53 words
The method of claim 1 wherein the fixing resin medium is a copolymer of an aromatic vinyl compound selected from the group consisting of styrene, vinyl toluene, alphamethyl-styrene, alpha-chloro-styrene, vinylxylene and vinyl naphthalene and an ethylenically unsaturated carboxylic acid ester selected from the group consisting of ethylacrylate, methylmethacrylate, butylacrylate, butylmethacrylate, 2-ethylhexylacrylate, and 2-ethylhexylmethacrylate.
Claim 12
Dependent Claim
34 words
The method of claim 10 wherein the copolymer has a weight average molecular weight of at least 2000 and a softening point by the ring-and-ball method in the range of 70° to 200° C.
Claim 13
Dependent Claim
30 words
The method of claim 1 wherein the toner further comprises a pigment selected from the group consisting of coloring pigment, magnetic pigment, body pigment, electrically conductive pigment, and mixtures thereof.
References Cited (Backward Citations)
DE2815857A1
Cited
US4533614A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-23 | 1990-08-25 | 1991-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-23 | 1994-08-25 | 1995-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-23 | 1998-08-25 | 1999-02-24 | $7700.00 | Window Closed / Lapsed |