Patent US4906548A successfully refreshed from Google Patents.
US4906548A
Expired / Lapsed
US
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Developer for developing electrostatic latent image and image forming method
Assignee: Canon Inc
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Filing: 1989-07-05
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Granted: 1990-03-06
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Expires: 2009-07-05
Abstract
Abstract A developer for developing electrostatic latent images comprises negatively chargeable toner particles and hydrophobic, negatively chargeable silica fine power, said silica fine powder being obtained by treating silica fine powder with a silane coupling agent represented by the following formula: R.sub.m SiY.sub.n or Y.sub.3 --Si--NH--Si--Y.sub.3 and treating further said treated silica fine powder with a silicone oil having the structure: ##STR1## An image forming method comprises forming an electrostatic latent image on a photosensitive drum; developing said latent image with a developer to form toner images, said developer comprising negatively chargeable toner particles and, hydrophobic, negatively chargeable silica fine powder, said silica fine powder being obtained by treating silica fine powder with a silane coupling agent represented by the following formula: R.sub.m SiY.sub.n or Y.sub.3 --Si--NH--Si--Y.sub.3 and treating further said treated silica fine powder with a silicone oil having the structure: ##STR2## electrostatically transferring the toner images formed to a transfer material; and cleaning the photosensitive drum after electrostatic transfer with a blade cleaning means.
Inventors
- 👤 Hitoshi Uchide
- 👤 Tetsuya Kuribayashi
- 👤 Manabu Ohno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:22
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/09708; G03G9/09716
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
224 words
An image forming method, which comprises forming an electrostatic latent image on a photosensitive drum; developing said latent image with a developer to form toner images, said developer comprising negatively chargeable toner particles and, hydrophobic, negatively chargeable silica fine powder, said silica fine powder being obtained by treating silica fine powder with a silane coupling agent represented by the following formula: R.sub.m SiY.sub.n or Y.sub.3 --Si--NH--Si--Y.sub.3 wherein R represents alkoxy group or chlorine atom, Y represents alkyl group, m represents positive integer of 1 to 3 and n represents positive integer of 3 to 1, with proviso that m+n is 4, and treating further said treated silica fine powder with a silicone oil having the structure: ##STR15## wherein R represents alkyl group having 1 to 3 carbon atoms, R' represents alkyl group different form R having 1 to 10 carbon atoms, halogen-modified alkyl group having 1 to 10 carbon atoms, phenyl-modified alkyl group or phenyl group, R" represents alkyl group having 1 to 3 carbon atoms or alkoxy group having 1 to 3 carbon atoms (with proviso that R" represents a group which may be either the same as or different from R), and x and y each represent positive integer; electrostatically transferring the toner images formed to a transfer material; and cleaning the photosensitive drum after electrostatic transfer with a blade cleaning means.
Claim 2
Dependent Claim
224 words
An image forming method, which comprises forming an electrostatic latent image on a photosensitive drum; developing said latent image with a developer to form toner images, said developer comprising negatively chargeable toner particles and, hydrophobic, negatively chargeable silica fine powder, said silica fine powder being obtained by treating silica fine powder with a silane coupling agent represented by the following formula: R.sub.m SiY.sub.n or Y.sub.3 --Si--NH--Si--Y.sub.3 wherein R represents alkoxy group or chlorine atom, Y represents alkyl group, m represents positive integer of 1 to 3 and n represents positive integer of 3 to 1, with proviso that m+n is 4, and treating further said treated silica fine powder with a silicone oil having the structure: ##STR15## wherein R represents alkyl group having 1 to 3 carbon atoms, R' represents alkyl group different form R having 1 to 10 carbon atoms, halogen-modified alkyl group having 1 to 10 carbon atoms, phenyl-modified alkyl group or phenyl group, R" represents alkyl group having 1 to 3 carbon atoms or alkoxy group having 1 to 3 carbon atoms (with proviso that R" represents a group which may be either the same as or different from R), and x and y each represent positive integer; electrostatically transferring the toner images formed to a transfer material; and cleaning the photosensitive drum after electrostatic transfer with a blade cleaning means.
Claim 3
Dependent Claim
18 words
An image forming method according to claim 1, wherein the electrostatic latent image is formed of positive charges.
Claim 4
Dependent Claim
29 words
An image forming method according to claim 1, wherein the electrostatic latent image is formed of negative charges and is developed by reversal developing with a negatively charged developer.
Claim 5
Dependent Claim
21 words
An image forming method according to claim 1, wherein the photosensitive drum has a surface hardness of 30 g or less.
Claim 6
Dependent Claim
22 words
An image forming method according to claim 4, wherein the photosensitive drum is provided with a photosensitive layer having an organic photoconductor.
Claim 7
Dependent Claim
26 words
An image forming method according to claim 1, wherein the electrostatic latent image is a digital latent image formed of 50 to 150 μm picture elements.
Claim 8
Dependent Claim
23 words
An image forming method according to claim 6, wherein the digital latent image is developed by reversal developing with a negatively charged developer.
Claim 9
Dependent Claim
21 words
An image forming method according to claim 1, wherein the photosensitive drum has a drum diameter of 50 mmφ or less.
Claim 10
Dependent Claim
31 words
An image forming method according to claim 1, wherein the toner images on the photosensitive drum are electrostatically transferred at an effective transfer current of 1×10 -7 to 10×10 -7 (A/cm).
Claim 11
Dependent Claim
33 words
An image forming method according to claim 1, wherein the photosensitive drum after electrostatic transfer is subjected to blade cleaning with a rubber plate blade with a rubber hardness of 20 to 70μ.
Claim 12
Dependent Claim
29 words
An image forming method according to claim 10, wherein the rubber plate blade is pressure contacted against the photosensitive drum with a penetration amount of 0.1 to 2 mm.
Claim 13
Dependent Claim
32 words
An image forming method according to claim 1, wherein the toner particles comprise 100 parts by weight of a binder resin and 10 to 200 parts by weight of a magnetic material.
Claim 14
Dependent Claim
23 words
An image forming method according to claim 12, wherein the toner particles contain 50 to 150 parts by weight of the magnetic material.
Claim 15
Dependent Claim
34 words
An image forming method according to claim 1, wherein the toner particles containing 0.1 to 10 parts by weight of a negatively chargeable charge controller per 100 parts by weight of the binder resin.
Claim 16
Dependent Claim
50 words
An image forming method according to claim 1, wherein the toner particles contain a metal complex compound of an aromatic hydroxycarboxylic acid having lipophilic group (A) and a metal complex salt type monoazo dye having free hydrophilic group (B), wherein compound (A) and compound (B) are negatively chargeable charge controllers.
Claim 17
Dependent Claim
35 words
An image forming method according to claim 15, wherein the toner particles contain 0.1 to 10 parts by weight of combined compound (A) and compound (B) per 100 parts by weight of the binder resin.
Claim 18
Dependent Claim
26 words
An image forming method according to claim 16, wherein the compound (A) and the compound (B) are contained at a weight ratio f 1:10 to 10:1.
Claim 19
Dependent Claim
22 words
An image forming method according to claim 1, wherein the silica fine powder has an average particle size of 0.001 to 2μ.
Claim 20
Dependent Claim
24 words
An image forming method according to claim 1, wherein the silica fine powder has hydrophobicity of 90% or higher, as determined by its transmittance.
Claim 21
Dependent Claim
26 words
An image forming method according to claim 19, wherein the silica fine powder has methanol hydrophobicity of 65 or higher according to the methanol titration test.
Claim 22
Dependent Claim
76 words
An image forming method according to claim 1, wherein the silica fine powder is treated with 5 to 40 parts by weight of the silane coupling agent per 100 parts by weight of the untreated silica fine powder having a BET specific surface are of 40 to 400 m 2 /g, and further treated with A/25±A/30 parts by weight (A represents the BET specific surface area value of the silica fine powder) of said silicone oil.
Claim 23
Dependent Claim
55 words
An image forming method according to claim 21, wherein the silica fine powder is subjected to heat treatment at a temperature of 50° to 150° C. after the treatment with the silane coupling agent and further subjected to heat treatment at a temperature of 150° to 350° C. after the treatment with the silicone oil.
Claim 24
Dependent Claim
33 words
An image forming method according to claim 22, wherein the silica fine powder is subjected to heat treatment at a temperature of 200° to 300° C. after the treatment with the silicone oil.
Claim 25
Dependent Claim
26 words
An image forming method according to claim 1, wherein said silicone oil has a viscosity of 50 to 1000 centistokes at a temperature of 25° C.
Claim 26
Dependent Claim
45 words
An image forming method according to claim 1, wherein 50% or more of the silanol groups existing on the surfaces of silica particles have reacted with the silane coupling agent at the stage when the silica fine powder is treated with the silane coupling agent.
Claim 27
Dependent Claim
32 words
An image forming method according to claim 1, wherein 0.01 to 20 parts by weight of the treated silica fine powder is added per 100 parts by weight of the toner particles.
Claim 28
Dependent Claim
30 words
An image forming method according to claim 26, wherein 0.1 to 3 parts by weight of the treated silica fine powder is added per 100 parts of the toner particles.
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