Patent EP0367245A2 successfully refreshed from Google Patents.
EP0367245A2
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An image forming apparatus
Assignee: Canon Inc
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Filing: 1989-10-31
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Granted: —
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Expires: 2009-10-31
Abstract
Abstract An image forming apparatus includes a movable image bearing member; an image forming device for forming an image on the image bearing member; a charging member disposed opposed to the image bearing member; and bias application device for applying a bias voltage to the charging member, wherein the bias applying device effects a constant voltage control to the charging member when an image area of the image bearing member is in a charging region of the charging member, and effects a constant current control during at least a part of a period in which an area of the image bearing member other than the image area is in the charging region, and wherein a level of a constant voltage of the constant voltage control is determined during the constant current control.
Inventors
- 👤 Yukihiro Ohzeki
- 👤 Koichi Hiroshima
- 👤 Junji Araya
- 👤 Yasushi Sato
- 👤 Toshio Miyamoto
- 👤 Kimio Nakahata
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 04:40
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/1665; G03G15/167; G03G15/1675
Claims Analysis
Total Claims: 74
Claim 1
Independent Claim
130 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member disposed opposed to said image bearing member; and bias application means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member when an image area of said image bearing member is in a charging region of said charging member, and effects a constant current control during at least a part of a period in which an area of said image bearing member other than the image area is in the charging region, and wherein a level of a constant voltage of the constant voltage control is determined during the constant current control.
Claim 2
Dependent Claim
130 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member disposed opposed to said image bearing member; and bias application means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member when an image area of said image bearing member is in a charging region of said charging member, and effects a constant current control during at least a part of a period in which an area of said image bearing member other than the image area is in the charging region, and wherein a level of a constant voltage of the constant voltage control is determined during the constant current control.
Claim 3
Dependent Claim
17 words
An apparatus according to Claim 1, wherein said charging member is contactable to said image bearing member.
Claim 4
Dependent Claim
59 words
An apparatus according to Claim 1, wherein the image on the image bearing member is transferred onto the transfer material by passing the transfer material between said image bearing member and said charging member so that the transfer material is contacted to the surface of the image bearing member on which the image is formed, in the transfer region.
Claim 5
Dependent Claim
36 words
An apparatus according to Claim 1, wherein said image forming means includes latent image forming means for forming a latent image on an image bearing member and developing means for developing the latent image with toner.
Claim 6
Dependent Claim
30 words
An apparatus according to Claim 4, wherein the image area of said image bearing member is an area in which a toner image is formed on said image bearing member.
Claim 7
Dependent Claim
25 words
An apparatus according to Claim 3, wherein the image area of said image bearing member is an area which is contacted to the transfer material.
Claim 8
Dependent Claim
34 words
An apparatus according to Claim 1, wherein the area other than the image area is upstream and downstream sides of the image area with respect to a movement direction of said image bearing member.
Claim 9
Dependent Claim
35 words
An apparatus according to Claim 3, wherein the period includes a period in which the transfer material is in the charging region, and the area other than the image area is in the charging region.
Claim 10
Dependent Claim
25 words
An apparatus according to Claim 1, wherein the period includes a period in which said image bearing member is moved before the image is produced.
Claim 11
Dependent Claim
35 words
An apparatus according to Claim 1, wherein the area other than the image area includes an interval between the image region and a next image region during continuous image formation on said image bearing member.
Claim 12
Dependent Claim
37 words
An apparatus according to Claim 1, wherein the constant current control is effected before the image is produced, and the constant voltage control is effected until a predetermined number of the image areas reach the charging region.
Claim 13
Dependent Claim
30 words
An apparatus according to Claim 11, wherein when a predetermined number of image areas passes through the charging region, the constant current control is effected, and the operation is repeated.
Claim 14
Dependent Claim
17 words
An apparatus according to Claim 2, wherein said charging member is in the form of a roller.
Claim 15
Dependent Claim
17 words
An apparatus according to Claim 2, wherein said charging member is in the form of a belt.
Claim 16
Dependent Claim
21 words
An apparatus according to Claim 4, wherein said latent image forming means includes charging means for charging said image bearing member.
Claim 17
Dependent Claim
33 words
An apparatus according to Claim 15, wherein said charging means includes a charging member and bias voltage applying means having the same structure as the aforementioned charging member and bias applying means, respectively.
Claim 18
Dependent Claim
59 words
An apparatus according to Claim 15, wherein the image on the image bearing member is transferred onto the transfer material by passing the transfer material between said image bearing member and said charging member so that the transfer material is contacted to the surface of the image bearing member on which the image is formed, in the transfer region.
Claim 19
Dependent Claim
43 words
An apparatus according to Claim 17, wherein said image bearing member is a photosensitive member, and said latent image forming means includes exposure means for exposing said image bearing member electrically charged by said charging means to light in accordance with image information.
Claim 20
Dependent Claim
31 words
An apparatus according to Claim 17, wherein said charging means charges an area of said image bearing member which is to be in the transfer region during the constant current control.
Claim 21
Dependent Claim
33 words
An apparatus according to Claim 17 or 19, wherein said developing means develops the latent image with toner having a polarity which is the same as the charging property of the charging means.
Claim 22
Dependent Claim
43 words
An apparatus according to Claim 20, wherein said image bearing member is a photosensitive member, and said latent image forming means includes exposure means for exposing said image bearing member electrically charged by said charging means to light in accordance with image information.
Claim 23
Dependent Claim
55 words
An apparatus according to Claim 15 or 21, wherein said exposure means exposes to light at least a part of an area other than the image area of said image bearing member, and the exposed area is different from the area of the image bearing member in the transfer region during the constant current control.
Claim 24
Dependent Claim
31 words
An apparatus according to Claim 1, wherein said bias applying means stores a voltage produced during the constant current control, and the stored voltage is used during the constant voltage control.
Claim 25
Dependent Claim
172 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; transfer means for transferring the image from said image bearing member onto a transfer material in an image transfer region, said transfer means including a charging member opposed to said image bearing member exhibiting a different resistance in accordance with ambient conditions and bias application means for applying a bias voltage to said charging member, wherein said bias application means effects a constant voltage control to said charging member when an image area of said image bearing member is in the transfer region, and it effects a constant current control to said charging member during at least a part of a period in which an area of said image bearing member other than the image area is in the transfer region, wherein a level of a voltage of the constant voltage control is determined on the basis of a voltage produced in the transfer means during the constant current control.
Claim 26
Dependent Claim
172 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; transfer means for transferring the image from said image bearing member onto a transfer material in an image transfer region, said transfer means including a charging member opposed to said image bearing member exhibiting a different resistance in accordance with ambient conditions and bias application means for applying a bias voltage to said charging member, wherein said bias application means effects a constant voltage control to said charging member when an image area of said image bearing member is in the transfer region, and it effects a constant current control to said charging member during at least a part of a period in which an area of said image bearing member other than the image area is in the transfer region, wherein a level of a voltage of the constant voltage control is determined on the basis of a voltage produced in the transfer means during the constant current control.
Claim 27
Dependent Claim
17 words
An apparatus according to Claim 24, wherein said charging member is contactable to said image bearing member.
Claim 28
Dependent Claim
36 words
An apparatus according to Claim 24, wherein said image forming means includes latent image forming means for forming a latent image on an image bearing member and developing means for developing the latent image with toner.
Claim 29
Dependent Claim
30 words
An apparatus according to Claim 26, wherein the image area of said image bearing member is an area in which a toner image is formed on said image bearing member.
Claim 30
Dependent Claim
25 words
An apparatus according to Claim 24, wherein the image area of said image bearing member is an area which is contacted to the transfer material.
Claim 31
Dependent Claim
34 words
An apparatus according to Claim 24, wherein the area other than the image area is upstream and downstream sides of the image area with respect to a movement direction of said image bearing member.
Claim 32
Dependent Claim
35 words
An apparatus according to Claim 24, wherein the period includes a period in which the transfer material is in the charging region, and the area other than the image area is in the charging region.
Claim 33
Dependent Claim
25 words
An apparatus according to Claim 24, wherein the period includes a period in which said image bearing member is moved before the image is produced.
Claim 34
Dependent Claim
35 words
An apparatus according to Claim 24, wherein the area other than the image area includes an interval between the image region and a next image region during continuous image formation on said image bearing member.
Claim 35
Dependent Claim
37 words
An apparatus according to Claim 24, wherein the constant current control is effected before the image is produced, and the constant voltage control is effected until a predetermined number of the image areas reach the transfer region.
Claim 36
Dependent Claim
30 words
An apparatus according to Claim 33, wherein when a predetermined number of image areas passes through the charging region, the constant current control is effected, and the operation is repeated.
Claim 37
Dependent Claim
17 words
An apparatus according to Claim 25, wherein said charging member is in the form of a roller.
Claim 38
Dependent Claim
17 words
An apparatus according to Claim 25, wherein said charging member is in the form of a belt.
Claim 39
Dependent Claim
21 words
An apparatus according to Claim 26, wherein said latent image forming means includes charging means for charging said image bearing member.
Claim 40
Dependent Claim
43 words
An apparatus according to Claim 37, wherein said image bearing member is a photosensitive member, and said latent image forming means includes exposure means for exposing said image bearing member electrically charged by said charging means to light in accordance with image information.
Claim 41
Dependent Claim
31 words
An apparatus according to Claim 37, wherein said charging means charges an area of said image bearing member which is to be in the transfer region during the constant current control.
Claim 42
Dependent Claim
32 words
An apparatus according to Claim 37 or 39, wherein said developing means develops the latent image with toner electrically charged to the same polarity as the charging property of said charging means.
Claim 43
Dependent Claim
43 words
An apparatus according to Claim 40, wherein said image bearing member is a photosensitive member, and said latent image forming means includes exposure means for exposing said image bearing member electrically charged by said charging means to light in accordance with image information.
Claim 44
Dependent Claim
55 words
An apparatus according to Claim 38 or 41, wherein said exposure means exposes to light at least a part of an area other than the image area of said image bearing member, and the exposed area is different from the area of the image bearing member in the transfer region during the constant current control.
Claim 45
Dependent Claim
22 words
An apparatus according to Claim 24, wherein the voltage level of said transfer means is a voltage produced at the charging member.
Claim 46
Dependent Claim
24 words
An apparatus according to Claim 24, wherein the voltage level produced in said transfer means is a voltage produced in the bias applying means.
Claim 47
Dependent Claim
33 words
An apparatus according to Claim 24, wherein said bias applying means stores the voltage produced in said transfer means, and controls said charging member using the stored voltage, during the constant voltage control.
Claim 48
Dependent Claim
22 words
An apparatus according to Claim 24, wherein the voltage produced in said transfer means corresponds to a resistance of the charging member.
Claim 49
Dependent Claim
161 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member opposed to said image bearing member and having a resistance which varies in accordance with an ambient condition; bias application means for applying a bias voltage to said charging member, wherein said bias application means effects a constant voltage control to said charging member when an image area of said image bearing member is in a charging region of said charging member, and it effects a constant current control to said charging member during a part of a period in which an area of said photosensitive member other than the image area is in the charging region; and storing means for storing a voltage corresponding to the resistance of the charging member during the constant current control, and determines a level of a voltage of the constant voltage control on the basis of the stored voltage.
Claim 50
Dependent Claim
161 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member opposed to said image bearing member and having a resistance which varies in accordance with an ambient condition; bias application means for applying a bias voltage to said charging member, wherein said bias application means effects a constant voltage control to said charging member when an image area of said image bearing member is in a charging region of said charging member, and it effects a constant current control to said charging member during a part of a period in which an area of said photosensitive member other than the image area is in the charging region; and storing means for storing a voltage corresponding to the resistance of the charging member during the constant current control, and determines a level of a voltage of the constant voltage control on the basis of the stored voltage.
Claim 51
Dependent Claim
17 words
An apparatus according to Claim 47, wherein said charging member is contactable to said image bearing member.
Claim 52
Dependent Claim
59 words
An apparatus according to Claim 47, wherein the image on the image bearing member is transferred onto the transfer material by passing the transfer material between said image bearing member and said charging member so that the transfer material is contacted to the surface of the image bearing member on which the image is formed, in the transfer region.
Claim 53
Dependent Claim
36 words
An apparatus according to Claim 47, wherein said image forming means includes latent image forming means for forming a latent image on an image bearing member and developing means for developing the latent image with toner.
Claim 54
Dependent Claim
30 words
An apparatus according to Claim 50, wherein the image area of said image bearing member is an area in which a toner image is formed on said image bearing member.
Claim 55
Dependent Claim
25 words
An apparatus according to Claim 49, wherein the image area of said image bearing member is an area which is contacted to the transfer material.
Claim 56
Dependent Claim
34 words
An apparatus according to Claim 47, wherein the area other than the image area is upstream and downstream sides of the image area with respect to a movement direction of said image bearing member.
Claim 57
Dependent Claim
35 words
An apparatus according to Claim 49, wherein the period includes a period in which the transfer material is in the charging region, and the area other than the image area is in the charging region.
Claim 58
Dependent Claim
25 words
An apparatus according to Claim 47, wherein the period includes a period in which said image bearing member is moved before the image is produced.
Claim 59
Dependent Claim
35 words
An apparatus according to Claim 47, wherein the area other than the image area includes an interval between the image region and a next image region during continuous image formation on said image bearing member.
Claim 60
Dependent Claim
37 words
An apparatus according to Claim 47, wherein the constant current control is effected before the image is produced, and the constant voltage control is effected until a predetermined number of the image areas reach the charging region.
Claim 61
Dependent Claim
30 words
An apparatus according to Claim 57, wherein when a predetermined number of image areas passes through the charging region, the constant current control is effected, and the operation is repeated.
Claim 62
Dependent Claim
17 words
An apparatus according to Claim 48, wherein said charging member is in the form of a roller.
Claim 63
Dependent Claim
17 words
An apparatus according to Claim 48, wherein said charging member is in the form of a belt.
Claim 64
Dependent Claim
21 words
An apparatus according to Claim 50, wherein said latent image forming means includes charging means for charging said image bearing member.
Claim 65
Dependent Claim
33 words
An apparatus according to Claim 61, wherein said charging means includes a charging member and bias voltage applying means having the same structure as the aforementioned charging member and bias applying means, respectively.
Claim 66
Dependent Claim
59 words
An apparatus according to Claim 61, wherein the image on the image bearing member is transferred onto the transfer material by passing the transfer material between said image bearing member and said charging member so that the transfer material is contacted to the surface of the image bearing member on which the image is formed, in the transfer region.
Claim 67
Dependent Claim
43 words
An apparatus according to Claim 63, wherein said image bearing member is a photosensitive member, and said latent image forming means includes exposure means for exposing said image bearing member electrically charged by said charging means to light in accordance with image information.
Claim 68
Dependent Claim
31 words
An apparatus according to Claim 63, wherein said charging means charges an area of said image bearing member which is to be in the transfer region during the constant current control.
Claim 69
Dependent Claim
33 words
An apparatus according to Claim 63 or 65, wherein said developing means develops the latent image with toner having a polarity which is the same as the charging property of the charging means.
Claim 70
Dependent Claim
43 words
An apparatus according to Claim 66, wherein said image bearing member is a photosensitive member, and said latent image forming means includes exposure means for exposing said image bearing member electrically charged by said charging means to light in accordance with image information.
Claim 71
Dependent Claim
55 words
An apparatus according to Claim 61 or 67, wherein said exposure means exposes to light at least a part of an area other than the image area of said image bearing member, and the exposed area is different from the area of the image bearing member in the transfer region during the constant current control.
Claim 72
Dependent Claim
33 words
An apparatus according to Claim 47, wherein said voltage producing means stores the voltage produced, and said bias applying means controls said charging member using the stored voltage, during the constant voltage control.
Claim 73
Dependent Claim
110 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member disposed opposed to said image bearing member; and bias application means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member when an image area of said image bearing member is in a charging region of said charging member, and effects a constant current control during at least a part of a period in which an area of said image bearing member other than the image area is in the charging region.
Claim 74
Dependent Claim
110 words
An image forming apparatus, comprising: a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member disposed opposed to said image bearing member; and bias application means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member when an image area of said image bearing member is in a charging region of said charging member, and effects a constant current control during at least a part of a period in which an area of said image bearing member other than the image area is in the charging region.
References Cited (Backward Citations)
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