Patent EP0537793A2 successfully refreshed from Google Patents.
EP0537793A2
Expired / Lapsed
EP
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Image-transfer and sheet-separation apparatus
Assignee: Kyocera Mita Industrial Co Ltd
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Filing: 1992-10-19
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Granted: —
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Expires: 2012-10-19
Abstract
Abstract An image-transfer and sheet-separating apparatus (13) transfers an image toner-developed from a positive latent image and retained on a photoconductor drum (9) onto a copy sheet, and subsequently separates the sheet from the photoconductor drum (9). A sheet peel-separating AC voltage superimposed on an image-transferring DC bias voltage is applied to a transfer roller (31) which presses on the photoconductor drum (9). A post image-transfer charge-stripping element (35) removes charge from the copy sheet and is disposed in a portion of the sheet-transport stream forward of a nipping position at which the transfer roller (31) presses against the photoconductor drum (9). Thus, charges remaining on the copy sheet are discharged, ensuring high efficiency in image transfer and accordingly reducing the incidence of failure in the separation of the copy sheet from the photoconductor drum (9).
Inventors
- 👤 Ryuji Haibara Prince Haitsu 606 Wataki
- 👤 Shigeo Fujita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 17:40
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/65; G03G15/6532; G03G15/6535; G03G15/14; G03G15/16; G03G15/1665; G03G15/167; G03G15/1675
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
108 words
An apparatus for transferring onto a sheet an image, retained on an image receiver (9) and toner-developed from a positive latent image, and for subsequently separating the sheet from the image receiver (9), comprising: - a transfer roller (31) pressing on the image receiver (9); - means (36 - 38) for applying to the transfer roller (31) AC voltage (37) and DC voltage (38); and - means (35) for removing electric charge from the sheet, provided in the transport path in a downstream position of the transfer roller (31) pressing against the image receiver (9), with respect to a transport direction of the sheet during the image transferring.
Claim 2
Dependent Claim
17 words
The apparatus according to claim 1, wherein the image receiver (9) is a rotatable photoconductor drum (9).
Claim 3
Dependent Claim
25 words
The apparatus according to claim 2, wherein the transfer roller (31) is disposed in a position under and axially parallel with the photoconductor drum (9).
Claim 4
Dependent Claim
28 words
The apparatus according to claim 2 or 3, further comprising means (30, 34) for approaching the transfer roller (31) to and retracting it from the photoconductor drum (9).
Claim 5
Independent Claim
38 words
The apparatus according to any of claims 2 to 4, further comprising a case (30), an upper portion of which rotatably (02) supports the transfer roller (31), wherein the case (30) is provided under the photoconductor drum (9).
Claim 6
Dependent Claim
21 words
The apparatus according to claim 5, wherein the case (30) is pivotally (01) supported along one end of an underside thereof.
Claim 7
Independent Claim
31 words
The apparatus according to any of claims 4 to 6, wherein the approaching/retracting means (30, 34) includes a rotatable eccentric wheel (34) in contact with the underside of the case (30).
Claim 8
Dependent Claim
24 words
The apparatus according to claim 7, wherein a turning angle of the eccentric wheel (34) is determined corresponding to a thickness of the sheet.
Claim 9
Independent Claim
59 words
An apparatus according to any of claims 5 to 8, further comprising: - a fibrous brush roller (32) rotatably provided in the case (30) and pressing on a lower surface of the transfer roller (31); and - a blade (33), having a tip extending into a lower portion of the fibrous brush roller (32), provided in the case (30).
Claim 10
Independent Claim
27 words
The apparatus according to any of claims 1 to 9, wherein the charge-removing means (35) is a charge-stripping brush (35), an edge of which contacts the sheet.
Claim 11
Dependent Claim
29 words
The apparatus according to claim 10, wherein the charge-stripping brush (35) in contacting a surface of the sheet opposite to that containing the transferred toner-developed image removes charges therefrom.
Claim 12
Dependent Claim
16 words
The apparatus according to claim 10 or 11, wherein the charge-stripping brush (35) contains conductive fibers.
Claim 13
Dependent Claim
13 words
The apparatus according to claim 12, wherein the conductive fibers are carbon fibers.
Claim 14
Independent Claim
17 words
The apparatus according to any of claims 10 to 13, wherein the charge-stripping brush (35) is grounded.
Claim 15
Independent Claim
39 words
The apparatus according to any of claims 1 to 14, wherein the voltage-applying means (36 - 38) includes a power supply unit (36) connected with the transfer roller (31) and having AC and DC power supply sections (37, 38).
Claim 16
Dependent Claim
89 words
The apparatus according to claim 15, wherein the DC power supply section (38), in applying a DC bias voltage to the transfer roller (31), charges the sheet with a charge of polarity reverse to a charge carried by the toner in image-development adherence to the photoconductor drum (9), so as to induce a transfer of the toner-developed image from the photoconductor drum (9) onto the sheet; and the AC power supply section (37) applies an AC voltage to the transfer roller (31) in order to electrically discharge the sheet.
Claim 17
Independent Claim
31 words
The apparatus according to any of claims 1 to 16, wherein the voltage-applying means (36 - 38) applies to the transfer roller (31) an AC voltage superimposed on a DC voltage.
Claim 18
Independent Claim
40 words
The apparatus according to any of claims 15 to 17, wherein the voltage applied to the transfer roller (31) by the AC and DC power supply sections (37, 38) is within the range of 500 V to 2 000 V.
Claim 19
Independent Claim
56 words
The apparatus according to any of claims 15 to 18, wherein the voltage applied by the AC power supply section (37) is within the range of 1 000 V to 1 500 V, and the voltage applied by the DC power supply section (38) is within the range of 1 000 V to 1 500 V.
Claim 20
Dependent Claim
41 words
The apparatus according to claim 15 or 16, wherein the voltage-applying means (36 - 38) includes a switch (39) for electrically connecting either the AC power supply section (37) or the DC power supply section (38) to the transfer roller (31).
Claim 21
Dependent Claim
31 words
The apparatus according to claim 20, further comprising a control unit (40) for selectively applying either the AC or DC voltage to the transfer roller (31) through switching the switch (39).
Claim 22
Dependent Claim
60 words
The apparatus according to claim 21, wherein the control unit (40) changes the switch (39) such that the AC voltage is applied to the transfer roller (31) when a transport-forward end of the sheet is located between the transfer roller (31) and the image receiver (9), and such that subsequently the DC voltage is applied to the transfer roller (31).
Claim 23
Dependent Claim
163 words
An image forming apparatus, comprising: - a scanning unit (8) for obtaining image information corresponding to an original image; - an image forming unit (15) including an image receiver (9), for developing with toner a latent image in positive correspondence to the image information retained on the image receiver (9); and - an image-transfer and sheet-separating apparatus (13) for transferring onto a sheet the toner-developed image retained on the image receiver (9), and for subsequently separating the sheet from the image receiver (9); wherein the image-transfer and sheet-separating apparatus (13) comprises - a transfer roller (31) pressing on the image receiver (9); - means (36 - 38) for applying to the transfer roller (31) AC voltage and DC voltage; and - means (35) for removing electric charge from the sheet, provided in the transport path in a downstream position of the transfer roller (31) pressing against the image receiver (9), with respect to a transport direction of the sheet during the image transferring.
Claim 24
Dependent Claim
36 words
The apparatus according to claim 23, wherein the image receiver (9) is a rotatable photoconductor drum (9), and the transfer roller (31) is disposed in a position under and axially parallel with the photoconductor drum (9).
Claim 25
Dependent Claim
34 words
The apparatus according to claim 24, further comprising a case (30), an upper portion of which rotatably (02) supports the transfer roller (31), wherein the case (30) is provided under the photoconductor drum (9).
Claim 26
Dependent Claim
21 words
The apparatus according to claim 25, wherein the case (30) is pivotally (01) supported along one end of an underside thereof.
Claim 27
Dependent Claim
42 words
The apparatus according to claim 25 or 26, further comprising a rotatable eccentric wheel (34) in contact with the underside of the case (30), wherein a turning angle of the eccentric wheel (34) is determined corresponding to a thickness of the sheet.
Claim 28
Independent Claim
59 words
The apparatus according to any of claims 25 to 27, further comprising: - a fibrous brush roller (32) rotatably provided in the case (30) and pressing on a lower surface of the transfer roller (31); and - a blade (33), having a tip extending into a lower portion of the fibrous brush roller (32), provided in the case (30).
Claim 29
Independent Claim
27 words
The apparatus according to any of claims 23 to 28, wherein the charge-removing means (35) is a charge-stripping brush (35), an edge of which contacts the sheet.
Claim 30
Dependent Claim
37 words
The apparatus according to claim 29, wherein the charge-stripping brush (35) in contacting a surface of the sheet opposite to that containing the transferred toner-developed image removes charges therefrom; and wherein the charge-stripping brush (35) is grounded.
Claim 31
Independent Claim
39 words
The apparatus according to any of claims 23 to 30, wherein the voltage-applying means (36 - 38) includes a power supply unit (36) connected with the transfer roller (31) and having AC and DC power supply sections (37, 38).
Claim 32
Independent Claim
31 words
The apparatus according to any of claims 23 to 31, wherein the voltage-applying means (36 - 38) applies to the transfer roller (31) an AC voltage superimposed on a DC voltage.
Claim 33
Dependent Claim
38 words
The apparatus according to claim 31 or 32, wherein the voltage applied to the transfer roller (31) by the AC and DC power supply sections (37, 38) is within the range of 500 V to 2 000 V.
Claim 34
Independent Claim
56 words
The apparatus according to any of claims 31 to 33, wherein the voltage applied by the AC power supply section (37) is within the range of 1 000 V to 1 500 V, and the voltage applied by the DC power supply section (38) is within the range of 1 000 V to 1 500 V.
Claim 35
Dependent Claim
39 words
The apparatus according to claim 31, wherein the voltage-applying means (36 - 38) includes a switch (39) for electrically connecting either the AC power supply section (37) or the DC power supply section (38) to the transfer roller (31).
Claim 36
Dependent Claim
86 words
The apparatus according to claim 35, further comprising a control unit (40) for selectively applying either the AC or DC voltage to the transfer roller (31) through switching the switch (39); and wherein the control unit (40) changes the switch (39) such that the AC voltage is applied to the transfer roller (31) when a transport-forward end of the sheet is located between the transfer roller (31) and the image receiver (9), and such that subsequently the DC voltage is applied to the transfer roller (31).
Claim 37
Independent Claim
107 words
An apparatus for transferring onto a sheet an image, retained on an image receiver (9) and toner-developed from a positive latent image, and for subsequently separating the sheet from the image receiver (9), comprising: - a transfer roller (31) pressing on the image receiver (9); - means (38) for applying DC voltage to the transfer roller (31); - means (37) for applying AC voltage to the transfer roller (31); and - a control unit (40) for applying for a predetermined interval the AC voltage to the transfer roller (31) after the sheet has been introduced into a nipping position thereof, and for subsequently applying the DC voltage.
Claim 38
Dependent Claim
37 words
The apparatus according to claim 37, wherein the image receiver (9) is a rotatable photoconductor drum (9), and the transfer roller (31) is disposed in a position under and axially in parallel with the photoconductor drum (9).
Claim 39
Dependent Claim
34 words
The apparatus according to claim 38, further comprising a case (30), an upper portion of which rotatably (02) supports the transfer roller (31), wherein the case (30) is provided under the photoconductor drum (9).
Claim 40
Dependent Claim
21 words
The apparatus according to claim 39, wherein the case (30) is rotatably (01) supported along one end of an underside thereof.
Claim 41
Dependent Claim
41 words
The apparatus according to claim 39 or 40, further comprising a rotatable eccentric wheel (34) in contact with the underside of the case (30), wherein a turning angle of the eccentric wheel (34) is determined corresponding to thickness of the sheet.
Claim 42
Independent Claim
59 words
The apparatus according to any of claims 39 to 41, further comprising: - a fibrous brush roller (32) rotatably provided in the case (30) and pressing on a lower surface of the transfer roller (31); and - a blade (33), having a tip extending into a lower portion of the fibrous brush roller (32), provided in the case (30).
References Cited (Backward Citations)
No citation records indexed.
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