Patent US6002900A successfully refreshed from Google Patents.
US6002900A
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US
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Image forming method, image forming apparatus and process cartridge
Assignee: Canon Inc
•
Filing: 1998-06-15
•
Granted: 1999-12-14
•
Expires: 2018-06-15
Abstract
Abstract Improvement has been made in an image forming method comprising charging electrically an image holding member, forming a latent electrostatic image on the image holding member, developing the latent image with a toner, transferring the toner image onto a toner image receiving medium, and recovering untransferred toner. In this method, a magnetic brush formed from magnetic particles electrifies the image holding member by contact with the image holding member surface, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member, wherein the toner has a weight-average particle diameter of not larger than 1/3 of average particle diameter of the magnetic particles and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 50% by volume. Thereby, contamination of the magnetic particles by the toner and interception of the electric conduction path in the magnetic brush are prevented, and deterioration of the toner is prevented without excessive shearing of the recovered toner with magnetic particles.
Inventors
- 👤 Harumi Ishiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:19
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0208; G03G15/0241; G03G21/00; G03G21/0005; G03G21/0064; G03G9/00; G03G9/08; G03G9/0819; G03G2215/00; G03G2215/02; G03G2215/021; G03G2215/022
Claims Analysis
Total Claims: 75
Claim 1
Independent Claim
238 words
An image forming method comprising a charging step using a charging means for electrifying an image holding member for holding an electrostatic latent image; an electrostatic latent image formation step for forming an electrostatic latent image on the electrified image holding member; a development step for developing the electrostatic latent image held on the image holding member with a toner stored in a development device to form a toner image; a transfer step for transferring the toner image onto a transfer-receiving medium, and a recovery step for recovering the toner remaining after the image transfer on the image holding member simultaneously with the development by the development device, wherein the charging means is a magnetic brush charger formed from magnetically confined magnetic particles; the magnetic brush charger electrifies the image holding member by bringing the magnetic brush of the magnetic brush charger into contact with the surface of the image holding member, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member; the toner has a weight-average particle diameter (D 4 ) of not larger than 1/3 of average particle diameter of the magnetic particles; and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 5.0% by volume.
Claim 2
Dependent Claim
238 words
An image forming method comprising a charging step using a charging means for electrifying an image holding member for holding an electrostatic latent image; an electrostatic latent image formation step for forming an electrostatic latent image on the electrified image holding member; a development step for developing the electrostatic latent image held on the image holding member with a toner stored in a development device to form a toner image; a transfer step for transferring the toner image onto a transfer-receiving medium, and a recovery step for recovering the toner remaining after the image transfer on the image holding member simultaneously with the development by the development device, wherein the charging means is a magnetic brush charger formed from magnetically confined magnetic particles; the magnetic brush charger electrifies the image holding member by bringing the magnetic brush of the magnetic brush charger into contact with the surface of the image holding member, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member; the toner has a weight-average particle diameter (D 4 ) of not larger than 1/3 of average particle diameter of the magnetic particles; and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 5.0% by volume.
Claim 3
Dependent Claim
40 words
The image forming method according to claim 1, wherein the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 4.5% by volume.
Claim 4
Dependent Claim
40 words
The image forming method according to claim 1, wherein the magnetic particles contain particles of diameter of not less than 1.5 times the average particle diameter of the magnetic particles at a content ranging from 0 to 20.0% by volume.
Claim 5
Dependent Claim
40 words
The image forming method according to claim 1, wherein the magnetic particles contain particles of diameter of not less than 1.5 times the average particle diameter of the magnetic particles at a content ranging from 0 to 15.0% by volume.
Claim 6
Dependent Claim
39 words
The image forming method according to claim 1, wherein the magnetic particles contain particles of diameter of 2/3 to 4/3 of the average particle diameter of the magnetic particles at a content ranging from 60.0 to 100% by volume.
Claim 7
Dependent Claim
39 words
The image forming method according to claim 1, wherein the magnetic particles contain particles of diameter of 2/3 to 4/3 of the average particle diameter of the magnetic particles at a content ranging from 65.0 to 100% by volume.
Claim 8
Dependent Claim
23 words
The image forming method according to claim 1, wherein the magnetic particles have an average particle diameter ranging from 10 to 100 μm.
Claim 9
Dependent Claim
23 words
The image forming method according to claim 1, wherein the magnetic particles have an average particle diameter ranging from 15 to 50 μm.
Claim 10
Dependent Claim
25 words
The image forming method according to claim 1, wherein the toner has a weight-average particle diameter (D 4 ) ranging from 1 to 20 μm.
Claim 11
Dependent Claim
25 words
The image forming method according to claim 1, wherein the toner has a weight-average particle diameter (D 4 ) ranging from 2 to 10 μm.
Claim 12
Dependent Claim
27 words
The image forming method according to claim 1, wherein the toner has shape factors SF-1 ranging from 100 to 155 and SF-2 ranging from 100 to 145.
Claim 13
Dependent Claim
28 words
The image forming method according to claim 1, wherein the magnetic particles have shape factors SF-1 ranging from 100 to 150 and SF-2 ranging from 100 to 130.
Claim 14
Dependent Claim
47 words
The image forming method according to claim 1, wherein the toner has shape factors SF-1 ranging from 100 to 155 and SF-2 ranging from 100 to 145, and the magnetic particles have shape factors SF-1 ranging from 100 to 150 and SF-2 ranging from 100 to 130.
Claim 15
Dependent Claim
24 words
The image forming method according to claim 1, wherein the magnetic particles have a volume resistivity ranging from 1×10 5 to 1×10 9 Ω.cm.
Claim 16
Dependent Claim
47 words
The image forming method according to claim 1, wherein the magnetic particles are a mixture of main magnetic particles having a volume resistivity ranging from 1×10 5 to 1×10 9 Ω.cm, and auxiliary magnetic particles having a volume resistivity ranging from 1×10 0 to 1×10 5 Ω.cm.
Claim 17
Dependent Claim
47 words
The image forming method according to claim 1, wherein the magnetic particles are a mixture of main magnetic particles having a volume resistivity ranging from 1×10 6 to 1×10 8 Ω.cm, and auxiliary magnetic particles having a volume resistivity ranging from 1×10 3 to 1×10 5 Ω.cm.
Claim 18
Dependent Claim
47 words
The image forming method according to claim 1, wherein the magnetic particles, which is a mixture of main magnetic particles and auxiliary magnetic particles, contain 10 to 40 parts by weight of the auxiliary magnetic particles based on 100 parts by weight of the main magnetic particles.
Claim 19
Dependent Claim
29 words
The image forming method according to claim 1, wherein the image holding member has an outermost surface layer composed of a binder resin and electroconductive fine particles dispersed therein.
Claim 20
Dependent Claim
29 words
The image forming method according to claim 1, wherein the image holding member has an outermost surface layer of a volume resistivity of not more than 1×10 14 Ω.cm.
Claim 21
Dependent Claim
30 words
The image forming method according to claim 1, wherein the image holding member has an outermost surface layer of a volume resistivity ranging from 1×10 9 to 1×10 14 Ω.cm.
Claim 22
Dependent Claim
43 words
The image forming method according to claim 1, wherein the magnetic brush charger electrifies a surface layer of the image holding member by direct injection of electric charge by bringing the magnetic brush into contact with the surface of the image holding member.
Claim 23
Dependent Claim
28 words
The image forming method according to claim 1, wherein the magnetic brush charger electrifies the image holding member by application of a charging bias having a DC voltage.
Claim 24
Dependent Claim
34 words
The image forming method according to claim 1, wherein the magnetic brush charger electrifies the image holding member by application of a charging bias having a DC voltage and an AC component in superposition.
Claim 25
Dependent Claim
87 words
The image forming method according to claim 1, wherein a transfer section in the transfer step, a charging section in the charging step, and a development section in the development step are placed in the named order on the image holding member along the movement direction of the image holding member, and no cleaning member is provided which is brought into contact with the surface of the image holding member between the transfer section and the charging section, and between the charging section and the development section.
Claim 26
Dependent Claim
233 words
An image forming apparatus comprising an image holding member for holding an electrostatic latent image; a charging means for electrifying the image holding member; an electrostatic image forming means for forming an electrostatic latent image on the electrified image holding member; a development device storing a toner for toner image formation for developing the electrostatic latent image formed on the image holding member with the toner to form a toner image; and a transfer means for transferring the toner image onto a transfer-receiving medium, wherein the development device functions also to recover the toner remaining on the image holding member after the image transfer, the charging means is a magnetic brush charger formed from magnetically confined magnetic particles; the magnetic brush charger electrifies the image holding member by bringing the magnetic brush of the magnetic brush charger into contact with the surface of the image holding member, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member; the toner has a weight-average particle diameter (D 4 ) of not larger than 1/3 of average particle diameter of the magnetic particles; and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 5.0% by volume.
Claim 27
Dependent Claim
233 words
An image forming apparatus comprising an image holding member for holding an electrostatic latent image; a charging means for electrifying the image holding member; an electrostatic image forming means for forming an electrostatic latent image on the electrified image holding member; a development device storing a toner for toner image formation for developing the electrostatic latent image formed on the image holding member with the toner to form a toner image; and a transfer means for transferring the toner image onto a transfer-receiving medium, wherein the development device functions also to recover the toner remaining on the image holding member after the image transfer, the charging means is a magnetic brush charger formed from magnetically confined magnetic particles; the magnetic brush charger electrifies the image holding member by bringing the magnetic brush of the magnetic brush charger into contact with the surface of the image holding member, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member; the toner has a weight-average particle diameter (D 4 ) of not larger than 1/3 of average particle diameter of the magnetic particles; and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 5.0% by volume.
Claim 28
Dependent Claim
40 words
The image forming apparatus according to claim 25, wherein the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 4.5% by volume.
Claim 29
Dependent Claim
40 words
The image forming apparatus according to claim 25, wherein the magnetic particles contain particles of diameter of not less than 1.5 times the average particle diameter of the magnetic particles at a content ranging from 0 to 20.0% by volume.
Claim 30
Dependent Claim
40 words
The image forming apparatus according to claim 25, wherein the magnetic particles contain particles of diameter of not less than 1.5 times the average particle diameter of the magnetic particles at a content ranging from 0 to 15.0% by volume.
Claim 31
Dependent Claim
39 words
The image forming apparatus according to claim 25, wherein the magnetic particles contain particles of diameter of 2/3 to 4/3 of the average particle diameter of the magnetic particles at a content ranging from 60.0 to 100% by volume.
Claim 32
Dependent Claim
39 words
The image forming apparatus according to claim 25, wherein the magnetic particles contain particles of diameter of 2/3 to 4/3 of the average particle diameter of the magnetic particles at a content ranging from 65.0 to 100% by volume.
Claim 33
Dependent Claim
23 words
The image forming apparatus according to claim 25, wherein the magnetic particles have an average particle diameter ranging from 10 to 100 μm.
Claim 34
Dependent Claim
23 words
The image forming apparatus according to claim 25, wherein the magnetic particles have an average particle diameter ranging from 15 to 50 μm.
Claim 35
Dependent Claim
25 words
The image forming apparatus according to claim 25, wherein the toner has a weight-average particle diameter (D 4 ) ranging from 1 to 20 μm.
Claim 36
Dependent Claim
25 words
The image forming apparatus according to claim 25, wherein the toner has a weight-average particle diameter (D 4 ) ranging from 2 to 10 μm.
Claim 37
Dependent Claim
27 words
The image forming apparatus according to claim 25, wherein the toner has shape factors SF-1 ranging from 100 to 155 and SF-2 ranging from 100 to 145.
Claim 38
Dependent Claim
28 words
The image forming apparatus according to claim 25, wherein the magnetic particles have shape factors SF-1 ranging from 100 to 150 and SF-2 ranging from 100 to 130.
Claim 39
Dependent Claim
47 words
The image forming apparatus according to claim 25, wherein the toner has shape factors SF-1 ranging from 100 to 155 and SF-2 ranging from 100 to 145, and the magnetic particles have shape factors SF-1 ranging from 100 to 150 and SF-2 ranging from 100 to 130.
Claim 40
Dependent Claim
24 words
The image forming apparatus according to claim 25, wherein the magnetic particles have a volume resistivity ranging from 1×10 5 to 1×10 9 Ω.cm.
Claim 41
Dependent Claim
47 words
The image forming apparatus according to claim 25, wherein the magnetic particles are a mixture of main magnetic particles having a volume resistivity ranging from 1×10 5 to 1×10 9 Ω.cm, and auxiliary magnetic particles having a volume resistivity ranging from 1×10 0 to 1×10 5 Ω.cm.
Claim 42
Dependent Claim
47 words
The image forming apparatus according to claim 25, wherein the magnetic particles are a mixture of main magnetic particles having a volume resistivity ranging from 1×10 6 to 1×10 8 Ω.cm, and auxiliary magnetic particles having a volume resistivity ranging from 1×10 3 to 1×10 5 Ω.cm.
Claim 43
Dependent Claim
47 words
The image forming apparatus according to claim 25, wherein the magnetic particles, which is a mixture of main magnetic particles and auxiliary magnetic particles, contain 10 to 40 parts by weight of the auxiliary magnetic particles based on 100 parts by weight of the main magnetic particles.
Claim 44
Dependent Claim
29 words
The image forming apparatus according to claim 25, wherein the image holding member has an outermost surface layer composed of a binder resin and electroconductive fine particles dispersed therein.
Claim 45
Dependent Claim
29 words
The image forming apparatus according to claim 25, wherein the image holding member has an outermost surface layer of a volume resistivity of not more than 1×10 14 Ω.cm.
Claim 46
Dependent Claim
30 words
The image forming apparatus according to claim 25, wherein the image holding member has an outermost surface layer of a volume resistivity ranging from 1×10 9 to 1×10 14 Ω.cm.
Claim 47
Dependent Claim
43 words
The image forming apparatus according to claim 25, wherein the magnetic brush charger electrifies a surface layer of the image holding member by direct injection of electric charge by bringing the magnetic brush into contact with the surface of the image holding member.
Claim 48
Dependent Claim
28 words
The image forming apparatus according to claim 25, wherein the magnetic brush charger electrifies the image holding member by application of a charging bias having a DC voltage.
Claim 49
Dependent Claim
34 words
The image forming apparatus according to claim 25, wherein the magnetic brush charger electrifies the image holding member by application of a charging bias having a DC voltage and an AC component in superposition.
Claim 50
Dependent Claim
87 words
The image forming apparatus according to claim 25, wherein a transfer section in the transfer step, a charging section in the charging step, and a development section in the development step are placed in the named order on the image holding member along the movement direction of the image holding member, and no cleaning member is provided which is brought into contact with the surface of the image holding member between the transfer section and the charging section, and between the charging section and the development section.
Claim 51
Dependent Claim
227 words
A process cartridge detachably mountable to a main assembly of an image forming apparatus, comprising an image holding member for holding an electrostatic latent image; a charging means for electrifying the image holding member; and a development device storing a toner for toner image formation for developing the electrostatic latent image formed on the image holding member with the toner to form a toner image, and a transfer means for transferring the toner image onto a transfer-receiving medium, wherein the development device functions also to recover the toner remaining on the image holding member after the image transfer, the charging means is a magnetic brush charger formed from magnetically confined magnetic particles; the magnetic brush charger electrifies the image holding member by bringing the magnetic brush of the magnetic brush charger into contact with the surface of the image holding member, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member; the toner has a weight-average particle diameter (D 4 ) of not larger than 1/3 of average particle diameter of the magnetic particles; and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 5.0% by volume.
Claim 52
Dependent Claim
227 words
A process cartridge detachably mountable to a main assembly of an image forming apparatus, comprising an image holding member for holding an electrostatic latent image; a charging means for electrifying the image holding member; and a development device storing a toner for toner image formation for developing the electrostatic latent image formed on the image holding member with the toner to form a toner image, and a transfer means for transferring the toner image onto a transfer-receiving medium, wherein the development device functions also to recover the toner remaining on the image holding member after the image transfer, the charging means is a magnetic brush charger formed from magnetically confined magnetic particles; the magnetic brush charger electrifies the image holding member by bringing the magnetic brush of the magnetic brush charger into contact with the surface of the image holding member, recovers temporarily at least a part of the toner remaining on the image holding member after the image transfer, and transfers the recovered toner further again onto the image holding member; the toner has a weight-average particle diameter (D 4 ) of not larger than 1/3 of average particle diameter of the magnetic particles; and the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 5.0% by volume.
Claim 53
Dependent Claim
39 words
The process cartridge according to claim 49, wherein the magnetic particles contain particles of diameter of not larger than 1/3 of the average particle diameter of the magnetic particles at a content ranging from 0 to 4.5% by volume.
Claim 54
Dependent Claim
39 words
The process cartridge according to claim 49, wherein the magnetic particles contain particles of diameter of not less than 1.5 times the average particle diameter of the magnetic particles at a content ranging from 0 to 20.0% by volume.
Claim 55
Dependent Claim
39 words
The process cartridge according to claim 49, wherein the magnetic particles contain particles of diameter of not less than 1.5 times the average particle diameter of the magnetic particles at a content ranging from 0 to 15.0% by volume.
Claim 56
Dependent Claim
38 words
The process cartridge according to claim 49, wherein the magnetic particles contain particles of diameter of 2/3 to 4/3 of the average particle diameter of the magnetic particles at a content ranging from 60.0 to 100% by volume.
Claim 57
Dependent Claim
38 words
The process cartridge according to claim 49, wherein the magnetic particles contain particles of diameter of 2/3 to 4/3 of the average particle diameter of the magnetic particles at a content ranging from 65.0 to 100% by volume.
Claim 58
Dependent Claim
22 words
The process cartridge according to claim 49, wherein the magnetic particles have an average particle diameter ranging from 10 to 100 μm.
Claim 59
Dependent Claim
22 words
The process cartridge according to claim 49, wherein the magnetic particles have an average particle diameter ranging from 15 to 50 μm.
Claim 60
Dependent Claim
24 words
The process cartridge according to claim 49, wherein the toner has a weight-average particle diameter (D 4 ) ranging from 1 to 20 μm.
Claim 61
Dependent Claim
24 words
The process cartridge according to claim 49, wherein the toner has a weight-average particle diameter (D 4 ) ranging from 2 to 10 μm.
Claim 62
Dependent Claim
26 words
The process cartridge according to claim 49, wherein the toner has shape factors SF-1 ranging from 100 to 155 and SF-2 ranging from 100 to 145.
Claim 63
Dependent Claim
28 words
The process cartridge according to claim 49, wherein the magnetic particles have shape factor s SF-1 ranging from 100 to 150 and SF-2 ranging from 100 to 130.
Claim 64
Dependent Claim
46 words
The process cartridge according to claim 49, wherein the toner has shape factors SF-1 ranging from 100 to 155 and SF-2 ranging from 100 to 145, and the magnetic particles have shape factors SF-1 ranging from 100 to 150 and SF-2 ranging from 100 to 130.
Claim 65
Dependent Claim
23 words
The process cartridge according to claim 49, wherein the magnetic particles have a volume resistivity ranging from 1×10 5 to 1×10 9 Ω.cm.
Claim 66
Dependent Claim
46 words
The process cartridge according to claim 49, wherein the magnetic particles are a mixture of main magnetic particles having a volume resistivity ranging from 1×10 5 to 1×10 9 Ω.cm, and auxiliary magnetic particles having a volume resistivity ranging from 1×10 0 to 1×10 5 Ω.cm.
Claim 67
Dependent Claim
46 words
The process cartridge according to claim 49, wherein the magnetic particles are a mixture of main magnetic particles having a volume resistivity ranging from 1×10 6 to 1×10 8 Ω.cm, and auxiliary magnetic particles having a volume resistivity ranging from 1×10 3 to 1×10 5 Ω.cm.
Claim 68
Dependent Claim
46 words
The process cartridge according to claim 49, wherein the magnetic particles, which is a mixture of main magnetic particles and auxiliary magnetic particles, contain 10 to 40 parts by weight of the auxiliary magnetic particles based on 100 parts by weight of the main magnetic particles.
Claim 69
Dependent Claim
28 words
The process cartridge according to claim 49, wherein the image holding member has an outermost surface layer composed of a binder resin and electroconductive fine particles dispersed therein.
Claim 70
Dependent Claim
28 words
The process cartridge according to claim 49, wherein the image holding member has an outermost surface layer of a volume resistivity of not more than 1×10 14 Ω.cm.
Claim 71
Dependent Claim
29 words
The process cartridge according to claim 49, wherein the image holding member has an outermost surface layer of a volume resistivity ranging from 1×10 9 to 1×10 14 Ω.cm.
Claim 72
Dependent Claim
42 words
The process cartridge according to claim 49, wherein the magnetic brush charger electrifies a surface layer of the image holding member by direct injection of electric charge by bringing the magnetic brush into contact with the surface of the image holding member.
Claim 73
Dependent Claim
27 words
The process cartridge according to claim 49, wherein the magnetic brush charger electrifies the image holding member by application of a charging bias having a DC voltage.
Claim 74
Dependent Claim
33 words
The process cartridge according to claim 49, wherein the magnetic brush charger electrifies the image holding member by application of a charging bias having a DC voltage and an AC component in superposition.
Claim 75
Dependent Claim
85 words
The process cartridge according to claim 49, wherein a transfer section in the transfer step, a charging section in the charging step, and a development section in the development step are placed in the named order on the image holding member along the movement direction of the image holding member, and no cleaning member is provided which brought into contact with the surface of the image holding member between the transfer section and the charging section, and between the charging section and the development section.
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