US4254203A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dry process developing method employing magnetic toner
Assignee: Minolta Co Ltd
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Filing: 1978-07-17
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Granted: 1981-03-03
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Expires: 1998-07-17
Abstract
Abstract A dry process developing method which comprises: (a) preparing main particles comprising a highly insulating resin and magnetizable fine particles, with part of the magnetizable fine particles being exposed through the surfaces of the main particles, (b) preparing subordinate particles having a diameter smaller than that of the main particles and comprising a resin having frictional charging characteristics approximately equal to that of the resin constituting the main particles, (c) admixing said main and subordinate particles to form a developing material wherein said subordinate particles adhere to the portion of magnetic particles exposed through the surface of the main particles; and (d) applying the developing material onto an electrical potential pattern formed on a recording medium for developing the electrical potential pattern into a visible image.
Inventors
- 👤 Tateki Oka
- 👤 Susumu Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:31
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/06; G03G13/08; G03G13/09; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
178 words
A dry process method for developing an electrostatic latent image which comprises: (a) preparing main particles comprising a highly electrically insulating resin and magnetizable fine particles, part of said magnetizable fine particles being exposed through the surfaces of said main particles; (b) independently of step (a), preparing subordinate particles having a diameter smaller than that of said main particles and comprising a resin having frictional charging characteristics approximately equal to that of the resin constituting said main particles, (c) mixing said main and subordinate particles to form a developing material wherein said subordinate particles are adhered to the magnetizable particles exposed through the surface of said primary particles, (d) triboelectrically charging said highly electrically insulating resin in said particles to a polarity opposite that of an electrostatic latent image to be developed by frictional contact between said magnetizable particles exposed through the surface of said main particles and said highly electrically insulating resin and (e) applying said developing material onto an electrical potential pattern formed on a recording medium to develop said electrical potential pattern into visible image.
Claim 2
Dependent Claim
178 words
A dry process method for developing an electrostatic latent image which comprises: (a) preparing main particles comprising a highly electrically insulating resin and magnetizable fine particles, part of said magnetizable fine particles being exposed through the surfaces of said main particles; (b) independently of step (a), preparing subordinate particles having a diameter smaller than that of said main particles and comprising a resin having frictional charging characteristics approximately equal to that of the resin constituting said main particles, (c) mixing said main and subordinate particles to form a developing material wherein said subordinate particles are adhered to the magnetizable particles exposed through the surface of said primary particles, (d) triboelectrically charging said highly electrically insulating resin in said particles to a polarity opposite that of an electrostatic latent image to be developed by frictional contact between said magnetizable particles exposed through the surface of said main particles and said highly electrically insulating resin and (e) applying said developing material onto an electrical potential pattern formed on a recording medium to develop said electrical potential pattern into visible image.
Claim 3
Dependent Claim
26 words
A dry process developing method as claimed in claim 1, wherein said resins used for said main particles and subordinate particles are of the same material.
Claim 4
Dependent Claim
40 words
A dry process developing method as claimed in claim 1, wherein said main particles have average diameter in the region from 5 to 30 μm, with said subordinate particles having average diameter in the region from 1 to 15 μm.
Claim 5
Dependent Claim
28 words
A dry process developing method as claimed in claim 1, wherein resistivity of said resin for said main particles and subordinate particles is higher than 10 14 Ω.cm.
Claim 6
Dependent Claim
18 words
A dry process developing method as claimed in claim 1, wherein said main particles further includes coloring agent.
Claim 7
Dependent Claim
18 words
A dry process developing method as claimed in claim 1, wherein said subordinate particles further includes coloring agent.
Claim 8
Dependent Claim
16 words
A method according to claim 1 wherein the ratio of main to subordinate particles is 9:1-7:3.
Claim 9
Dependent Claim
26 words
The method according to claim 1 wherein said magnetic particles and resin are melted together and the resultant product is crushed to form said main particles.
Claim 10
Dependent Claim
24 words
The method according to claim 1 wherein the static resistivity of the main particles is higher than the dynamic resistivity of said main particles.
Claim 11
Dependent Claim
21 words
The method according to claim 1 wherein the static resistivity of said main particles is about 10 14 Ω.cm or higher.
Claim 12
Dependent Claim
19 words
The method according to claim 10 wherein the main particles have a dynamic resistivity of about 5×10 10 Ω.cm.
Claim 13
Dependent Claim
41 words
The method according to claim 1 wherein the main particles have an average diameter of 15 μm and the subordiate particles have an average diameter of about 8 μm and the weight ratio of said main to subordinate particles is 8:2.
Claim 14
Independent Claim
227 words
A method for developing an electrostatic latent image which comprises the steps of: (a) preparing a developing material composed of a mixture of main particles and subordinate particles prepared independently of said main particles, said main particles comprising a highly electrically insulating resin and magnetizable fine particles exposed through the surfaces of said main particles, said subordinate particles having a diameter smaller than that of said main particles and comprising a highly electrically insulating resin having frictional charging characteristics selectively the same as and approximately equal to that of said main particles, said highly electrically insulating resin portion of said main particles and subordinate particles being of a material which can be electrically charged upon frictional contact thereof with said magnetizable fine particles exposed through the surface of said main particles, said subordinate particles adhering to the portions of said magnetic particles exposed through the surface of said main particles, (b) triboelectrically charging said highly electrically insulating resin portion of said particles to a polarity opposite that of the electrostatic latent image to be developed by frictional contact between said magnetizable particles exposed through the surface of said main particles and said highly electrically insulating resin and (c) forming magnetic brush bristles from said developing material and (d) contacting said electrostatic latent image with said brush bristles to thereby develop said latent image to a visible image.
Claim 15
Independent Claim
227 words
A method for developing an electrostatic latent image which comprises the steps of: (a) preparing a developing material composed of a mixture of main particles and subordinate particles prepared independently of said main particles, said main particles comprising a highly electrically insulating resin and magnetizable fine particles exposed through the surfaces of said main particles, said subordinate particles having a diameter smaller than that of said main particles and comprising a highly electrically insulating resin having frictional charging characteristics selectively the same as and approximately equal to that of said main particles, said highly electrically insulating resin portion of said main particles and subordinate particles being of a material which can be electrically charged upon frictional contact thereof with said magnetizable fine particles exposed through the surface of said main particles, said subordinate particles adhering to the portions of said magnetic particles exposed through the surface of said main particles, (b) triboelectrically charging said highly electrically insulating resin portion of said particles to a polarity opposite that of the electrostatic latent image to be developed by frictional contact between said magnetizable particles exposed through the surface of said main particles and said highly electrically insulating resin and (c) forming magnetic brush bristles from said developing material and (d) contacting said electrostatic latent image with said brush bristles to thereby develop said latent image to a visible image.
Claim 16
Dependent Claim
58 words
An electrophotographic developing method as claimed in claim 13, wherein said main particles and subordinate particles each have tones of color selectively the same as and approximately equal to each other, said resins for each of said main particles and subordinate particles having softening points and melting points selectively the same as and approximately equal to each other.
Claim 17
Dependent Claim
21 words
An electrophotographic developing method as claimed in claim 13, wherein said main particles and subordinate particles are of the same resin.
Claim 18
Dependent Claim
39 words
An electrophotographic developing method as claimed in claim 13, wherein said main particles have average diameter in the region from 5 to 30 μm, with said subordinate particles having average diameter in the region from 1 to 15 μm.
Claim 19
Dependent Claim
27 words
An electrophotographic developing method as claimed in claim 13, wherein resistivity of said resins for said main particles and subordinate particles is higher than 10 14 Ω.cm.
Claim 20
Dependent Claim
16 words
The method according to claim 13 wherein the ratio of main to subordinate particles is 9:1-7:3.
Claim 21
Dependent Claim
26 words
The method according to claim 13 wherein said magnetic particles and resin are melted together and the resultant product is crushed to form said main particles.
Claim 22
Dependent Claim
24 words
The method according to claim 13 wherein the static resistivity of said main particles is higher than the dynamic resistivity of said main particles.
Claim 23
Dependent Claim
21 words
The method according to claim 13 wherein the static resistivity of said main particles is about 10 14 Ω.cm or higher.
Claim 24
Dependent Claim
19 words
The method according to claim 21 wherein the main particles have a dynamic resistivity of about 5×10 10 Ω.cm.
Claim 25
Dependent Claim
41 words
The method according to claim 13 wherein the main particles have an average diameter of 15 μm and the subordinate particles have an average diameter of about 8 μm and the weight ratio of said main to subordinate particles is 8:2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-02 | 1984-09-01 | 1985-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-02 | 1988-09-01 | 1989-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-02 | 1992-09-01 | 1993-03-03 | $7700.00 | Window Closed / Lapsed |