US5151736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image forming apparatus with controlled transfer voltage
Assignee: Canon Inc
•
Filing: 1991-04-08
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Granted: 1992-09-29
•
Expires: 2011-04-08
Abstract
Abstract An image forming apparatus includes an image bearing member carrying an image corresponding to image information; an image transfer device for transferring the image on the image bearing member onto a transfer material at a transfer position, wherein the transfer device includes a charging member contactable to a back side of the transfer material and voltage application means for applying a voltage to the charging member, wherein the voltage applying device effects a constant voltage control to the charging member when an image region of the image bearing member is at the transfer position, and effects a constant current control to the charging member at least a part of the other duration, and wherein a voltage level of the constant voltage control is determined on the basis of a voltage across the transfer device during the constant current control; wherein voltage applied to the charging member by the voltage applying device or a current through the charging member by the voltage applying device is limited.
Inventors
- 👤 Yukihiro Ohzeki
- 👤 Junji Araya
- 👤 Tatsunori Ishiyama
- 👤 Yasushi Sato
- 👤 Kimio Nakahata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:13
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/1665; G03G15/167; G03G15/1675
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
145 words
An image forming apparatus, comprising: a movable image bearing member; an image forming means for forming an image on said image bearing member; an image transfer charging member contactable to a back side of a transfer material at an image transfer position for effecting transfer of an image from said image bearing member to the transfer material; constant current control means for constant current controlling current through said image transfer charging member when there is no transfer material in the transfer position; and determining means for determining a charging voltage for application to said image transfer charging member, said determining means determines the charging voltage in accordance with a voltage produced during the constant current control by said constant current control means, wherein a voltage or current applied to said image transfer charging member during an image transfer operation is limited within a predetermined range.
Claim 2
Dependent Claim
145 words
An image forming apparatus, comprising: a movable image bearing member; an image forming means for forming an image on said image bearing member; an image transfer charging member contactable to a back side of a transfer material at an image transfer position for effecting transfer of an image from said image bearing member to the transfer material; constant current control means for constant current controlling current through said image transfer charging member when there is no transfer material in the transfer position; and determining means for determining a charging voltage for application to said image transfer charging member, said determining means determines the charging voltage in accordance with a voltage produced during the constant current control by said constant current control means, wherein a voltage or current applied to said image transfer charging member during an image transfer operation is limited within a predetermined range.
Claim 3
Dependent Claim
20 words
An apparatus is according to claim 1, wherein said image transfer charging member is contactable with said image being member.
Claim 4
Dependent Claim
18 words
An apparatus according to claim 1 or 2, wherein said image transfer charging member is a rotatable member.
Claim 5
Dependent Claim
19 words
An apparatus according to claim 3, wherein said image transfer charging member is in the form of a roller.
Claim 6
Dependent Claim
20 words
An apparatus according to claim 1, wherein said image transfer charging member has a resistance changeable with temperature and/or humidity.
Claim 7
Dependent Claim
56 words
An apparatus according to claim 1, wherein said determining means includes voltage detecting means for detecting a voltage of said image transfer charging member during the constant current control, and the voltage applied to said image transfer charging member during the transfer operation is determined on the basis of an output of said voltage detecting means.
Claim 8
Dependent Claim
36 words
An apparatus according to claim 1 or 6, wherein the voltage applied to the image transfer charging member or the current through the image transfer charging member is limited to be lower than a predetermined level.
Claim 9
Dependent Claim
36 words
An apparatus according to claim 1 or 6, wherein the voltage applied to the image transfer charging member and a current through the image transfer charging member is limited to be larger than a predetermined level.
Claim 10
Dependent Claim
34 words
An apparatus according to claim 7, wherein the voltage applied to the image transfer charging member and a current through the image transfer charging member is limited to be larger than a predetermined level.
Claim 11
Dependent Claim
30 words
An apparatus according to claim 1, further comprising constant voltage control means for effecting, during the transfer operation, a constant voltage operation with the voltage determined by said determining means.
Claim 12
Dependent Claim
28 words
An apparatus according to claim 1, wherein the voltage applied during the transferred operation increases the increase of the voltage during operation of said constant current control means.
Claim 13
Dependent Claim
42 words
An apparatus according to claim 1 or 11, wherein the voltage or the current is controlled to a predetermined level when the voltage determined in accordance with the voltage produced during the operation of said constant current control means exceeds the limit.
Claim 14
Dependent Claim
89 words
An apparatus according to claim 1 or 11, wherein when the voltage determined in accordance with the voltage produced during the operation of said constant current control means is within the limit, the voltage applied to the image transfer charging member changes with the voltage produced during the operation of the constant current control means; and the voltage or the current is controlled to a predetermined level when the voltage determined in accordance with the voltage produced during the operation of said constant current control means exceeds the limit.
Claim 15
Dependent Claim
43 words
An apparatus according to claim 1 or 11, wherein the voltage or the current is controlled to be a predetermined level when the voltage determined in accordance with the current flowing during the operation of said constant current control means exceeds the limit.
Claim 16
Dependent Claim
90 words
An apparatus according to claim 1 or 11, wherein when the voltage determined in accordance with the current flowing during the operation of said constant current control means is within the limit, the voltage applied to the image transfer charging member changes with the current flowing during the operation of the constant current control means; and the voltage or the current is controlled to be a predetermined level when the voltage determined in accordance with the current flowing during the operation of said constant current control means exceeds the limit.
Claim 17
Dependent Claim
20 words
An apparatus according to claim 1, wherein said constant current control means is operated prior to the image transfer operation.
Claim 18
Dependent Claim
175 words
An image forming apparatus, comprising: an image bearing member carrying an image corresponding to image formation; image transfer means for transferring the image on said image bearing member onto a transfer material at a transfer position, wherein said transfer means includes a charging member contactable to a back side of the transfer material and voltage application means for applying a voltage to said charging member, wherein said voltage applying means effects a constant voltage control to said charging member with a first voltage when an image region of said image bearing member is at the transfer position, and effects a second constant voltage control with a second voltage to said charging member at least a part of the other duration, and wherein a voltage level of the first constant voltage control is determined on the basis of a current through said transfer means during the second constant voltage control; wherein voltage applied to said charging member by said voltage applying means or a current through the charging member by said voltage applying means is limited.
Claim 19
Dependent Claim
175 words
An image forming apparatus, comprising: an image bearing member carrying an image corresponding to image formation; image transfer means for transferring the image on said image bearing member onto a transfer material at a transfer position, wherein said transfer means includes a charging member contactable to a back side of the transfer material and voltage application means for applying a voltage to said charging member, wherein said voltage applying means effects a constant voltage control to said charging member with a first voltage when an image region of said image bearing member is at the transfer position, and effects a second constant voltage control with a second voltage to said charging member at least a part of the other duration, and wherein a voltage level of the first constant voltage control is determined on the basis of a current through said transfer means during the second constant voltage control; wherein voltage applied to said charging member by said voltage applying means or a current through the charging member by said voltage applying means is limited.
Claim 20
Dependent Claim
22 words
An apparatus according to claim 17, wherein the image region is a region of said image bearing member having a toner image.
Claim 21
Dependent Claim
24 words
An apparatus according to claim 18, wherein the image region is a region where said image bearing member is contacted with the transfer material.
Claim 22
Dependent Claim
30 words
An apparatus according to claim 17, wherein said at least a part of the other duration is prior to the instance when the image region is at the transfer position.
Claim 23
Dependent Claim
17 words
An apparatus according to claim 17, wherein said charging member is contactable with said image bearing member.
Claim 24
Dependent Claim
16 words
An apparatus according to claim 17 or 21, wherein said charging member is a rotatable member.
Claim 25
Dependent Claim
17 words
An apparatus according to claim 22, wherein said charging member is in the form of a roller.
Claim 26
Dependent Claim
24 words
An apparatus according to claim 17, wherein said second constant voltage control is effected when the transfer material is absent at the transfer position.
Claim 27
Dependent Claim
18 words
An apparatus according to claim 17, wherein said charging member has a resistance changeable with temperature and/or humidity.
Claim 28
Dependent Claim
51 words
An apparatus according to claim 17, wherein said voltage applying means includes current detecting means for detecting a current through said transfer means during the second constant voltage control, and the voltage of the first constant voltage control is determined on the basis of an output of said current detecting means.
Claim 29
Dependent Claim
32 words
An apparatus according to claim 17 or 26, wherein the voltage applied to the charging member or the current through the charging member is limited to be lower than a predetermined level.
Claim 30
Dependent Claim
32 words
An apparatus according to claim 17 or 26, wherein the voltage applied to the charging member and a current through the charging member is limited to be larger than a predetermined level.
Claim 31
Dependent Claim
30 words
An apparatus according to claim 27, wherein the voltage applied to the charging member and a current through the charging member is limited to be larger than a predetermined level.
Claim 32
Dependent Claim
146 words
An image forming apparatus, comprising a movable image bearing member; an image forming means for forming an image on said image bearing member; an image transfer charging member contactable to a back side of a transfer material at an image transfer position for effecting transfer of an image from said image bearing member to the transfer material; constant voltage control means for constant voltage controlling voltage applied to said image transfer charging member when there is no transfer material in the transfer position; and determining means for determining a charging voltage for application to said image transfer charging member, said determining means determining the charging voltage in accordance with a current flowing during the constant voltage control by said constant voltage control means, wherein a voltage or current applied to said image transfer charging member during an image transfer operation is limited within a predetermined range.
Claim 33
Dependent Claim
146 words
An image forming apparatus, comprising a movable image bearing member; an image forming means for forming an image on said image bearing member; an image transfer charging member contactable to a back side of a transfer material at an image transfer position for effecting transfer of an image from said image bearing member to the transfer material; constant voltage control means for constant voltage controlling voltage applied to said image transfer charging member when there is no transfer material in the transfer position; and determining means for determining a charging voltage for application to said image transfer charging member, said determining means determining the charging voltage in accordance with a current flowing during the constant voltage control by said constant voltage control means, wherein a voltage or current applied to said image transfer charging member during an image transfer operation is limited within a predetermined range.
Claim 34
Dependent Claim
20 words
An apparatus according to claim 30, wherein said constant voltage control means is operated prior to the image transfer operation.
Claim 35
Dependent Claim
19 words
An apparatus according to claim 30, wherein said image transfer charging member is contactable with said image bearing member.
Claim 36
Dependent Claim
18 words
An apparatus according to claim 30 or 32, wherein said image transfer charging member is a rotatable member.
Claim 37
Dependent Claim
54 words
An apparatus according to claim 30, wherein said determining means includes current detection means for detecting a current through said image transfer charging member during the constant voltage control, and the voltage applied to the charging member during the transfer operation is determined on the basis of an output of said current detecting means.
Claim 38
Dependent Claim
34 words
An apparatus according to claim 30 or 34, wherein the voltage applied to the charging member or the current through the image transfer charging member is limited to be lower than a predetermined level.
Claim 39
Dependent Claim
34 words
An apparatus according to claim 35, wherein the voltage applied to the image transfer charging member and a current through the image transfer charging member is limited to be larger than another predetermined level.
Claim 40
Dependent Claim
34 words
An apparatus according to claim 35, wherein the voltage applied to the image transfer charging member and a current through the image transfer charging member is limited to be larger than a predetermined level.
Claim 41
Dependent Claim
30 words
An apparatus according to claim 30, further comprising constant voltage control means for effecting, during the transfer operation, a constant voltage operation with the voltage determined by said determining means.
Claim 42
Dependent Claim
28 words
An apparatus according to claim 30, wherein the voltage applied during the transfer operation increases with increase of the current during operation of said constant voltage control means.
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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) | 1995-09-29 | 1996-03-30 | 1996-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-29 | 2000-03-30 | 2000-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-29 | 2004-03-30 | 2004-09-29 | $7700.00 | Window Closed / Lapsed |