EP0280542A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
An image forming apparatus
Assignee: Canon Inc
•
Filing: 1988-02-25
•
Granted: —
•
Expires: 2008-02-25
Abstract
Abstract An image forming apparatus includes a charger for charging an image bearing member. The charger includes a charging member (4) contacted to the charger bearing member and supplied with a voltage. The charger functions both as discharging device (switch to B) and charging device (switch to A) by switching a voltage applied thereto. The apparatus is made smaller, simpler and less expensive in cost.
Inventors
- 👤 Junji Araya
- 👤 Noribumi Koitabashi
- 👤 Shunji Nakamura
- 👤 Hiromitsu Hirabayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 08:26
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0208; G03G15/0216; G03G21/00; G03G21/06
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
121 words
An image forming apparatus, comprising: a movable image bearing member on which an image is repetitively formed; means for forming an image on said image bearing member; said image forming means including means for charging said image bearing member, which includes a charging member contacted to said image bearing member and means for applying first and second vibratory voltages to said charging means; wherein said charging means also functions as means for electrically discharging said image bearing member, and wherein when it functions as the discharging means, said voltage applying means applies to said charging member a second vibratory voltage having a center of vibration whose absolute value is smaller than that of a center of vibration in the first voltage.
Claim 2
Dependent Claim
121 words
An image forming apparatus, comprising: a movable image bearing member on which an image is repetitively formed; means for forming an image on said image bearing member; said image forming means including means for charging said image bearing member, which includes a charging member contacted to said image bearing member and means for applying first and second vibratory voltages to said charging means; wherein said charging means also functions as means for electrically discharging said image bearing member, and wherein when it functions as the discharging means, said voltage applying means applies to said charging member a second vibratory voltage having a center of vibration whose absolute value is smaller than that of a center of vibration in the first voltage.
Claim 3
Dependent Claim
24 words
An apparatus according to Claim 1, wherein each of the vibratory voltages is provided with superimposition of a DC voltage and an AC voltage.
Claim 4
Dependent Claim
60 words
An apparatus according to Claim 2, wherein said voltage applying means includes first means for applying the superimposed voltage to said charging member and second means for applying only the AC voltage to said charging member and means for selecting the first and second means, wherein the second means is selected upon said charging means functioning as the discharging means.
Claim 5
Dependent Claim
30 words
An apparatus according to Claim 1, wherein said image bearing member is electrically discharged during at least one turn of said image bearing member prior to image forming operation thereon.
Claim 6
Dependent Claim
51 words
An apparatus according to Claim 4, wherein said image forming means further includes means for forming a latent image corresponding to image information on said image bearing member after said image bearing member is charged by said charging means, and means for effecting a regular development to develop the latent image.
Claim 7
Dependent Claim
28 words
An apparatus according to Claim 1, wherein said image bearing member is electrically discharged during at least one rotation of said image bearing member after image formation thereon.
Claim 8
Dependent Claim
41 words
An apparatus according to Claim 1, 2, 4 or 6, wherein a peak-to-peak voltage of each of the vibratory voltage applied to said charging member is not less than twice an absolute value of a charge starting voltage image bearing member.
Claim 9
Dependent Claim
60 words
An apparatus according to Claim 1, wherein said charging member includes a surface region contacted to a surface of said image bearing member and another surface region continuous thereto in which said charging member is away from the surface of said image bearing member toward a downstream with respect to movement direction of the surface of said image bearing member.
Claim 10
Dependent Claim
18 words
An apparatus according to Claim 8, wherein said charging member is in the form of a rotatable roller.
Claim 11
Dependent Claim
33 words
An apparatus according to Claim 1, wherein said image bearing member is a photosensitive member, and wherein said image forming means includes exposure means for exposing said photosensitive member to image information light.
Claim 12
Independent Claim
15 words
An apparatus according to Claim l, wherein said charging member includes a conductive rubber material.
Claim 13
Dependent Claim
31 words
An apparatus according to Claim 1, wherein said charging member and said image bearing member are supported integrally in a process cartridge which is detachably mountable into said image forming apparatus.
Claim 14
Dependent Claim
43 words
An apparatus according to Claim 10, further comprising cleaning means for removing a residual developer from said image bearing member, wherein said charging means is disposed between said cleaning means and said exposure means in a movement direction of said image bearing member.
Claim 15
Dependent Claim
52 words
An apparatus according to Claim 10, wherein an absolute value of a center of vibration of the second vibratory voltage is set to be less than an absolute value of a saturated potential which is a potential saturated as a result of attenuation of a charged photosensitive member is exposed to light.
Claim 16
Dependent Claim
18 words
An apparatus according to Claim 1, wherein a center of vibration of the second vibratory voltage is zero.
Claim 17
Dependent Claim
15 words
An apparatus according to Claim 15, wherein the second vibratory voltage is an AC voltage.
Claim 18
Dependent Claim
133 words
An image forming apparatus, comprising: a movable image bearing member on which an image is repetitively formed; means for forming an image on said image bearing member; said image forming means including means for charging said image bearing member, which includes a charging member contacted to said image bearing member and means for applying a voltage to said charging means; wherein said charging means also functions as means for electrically discharging said image bearing member, and wherein said voltage applying means includes a first applying means for applying a first voltage to said charging member upon said image bearing member being charged and a second applying means for applying a second voltage to said charging member upon said image bearing member being electrically discharged, and means for selecting first and second applying means.
Claim 19
Dependent Claim
133 words
An image forming apparatus, comprising: a movable image bearing member on which an image is repetitively formed; means for forming an image on said image bearing member; said image forming means including means for charging said image bearing member, which includes a charging member contacted to said image bearing member and means for applying a voltage to said charging means; wherein said charging means also functions as means for electrically discharging said image bearing member, and wherein said voltage applying means includes a first applying means for applying a first voltage to said charging member upon said image bearing member being charged and a second applying means for applying a second voltage to said charging member upon said image bearing member being electrically discharged, and means for selecting first and second applying means.
Claim 20
Dependent Claim
22 words
An apparatus according to Claim 17, wherein said first voltage is provided by superimposition of a DC voltage and an AC voltage.
Claim 21
Dependent Claim
14 words
An apparatus according to Claim 17, wherein said second voltage includes an AC voltage.
Claim 22
Dependent Claim
14 words
An apparatus according to Claim 17, wherein said second voltage is a constant voltage.
Claim 23
Dependent Claim
23 words
An apparatus according to Claim 20, wherein charging member is grounded upon said image bearing member being discharged by said second applying means.
Claim 24
Dependent Claim
40 words
An apparatus according to Claim 17, 18 or 19, wherein a peak-to-peak voltage of each of the vibratory voltage applied to said charging member is not less than twice an absolute value of a charge starting voltage image bearing member.
Claim 25
Dependent Claim
72 words
An apparatus according to Claim 17, wherein said image bearing member is a photosensitive member, and wherein said image forming means includes exposure means for exposing said photosensitive member to image information light, said apparatus further comprising cleaning means for removing a residual developer from said image bearing member, wherein said charging means is disposed between said cleaning means and said exposure means in a movement direction of said image bearing member.
Claim 26
Dependent Claim
97 words
An image forming apparatus, comprising: a movable image bearing member on which images can repetitively be formed; means for forming images as electrical charges on the image bearing member; means for affecting the electric charge on the image bearing member, the latter means having a first mode of operation for charging the image bearing member in which a DC charging voltage superimposed with an AC uniforming voltage is applied to the image bearing member, and a second mode operation for discharging the image bearing member in which a charge flow circuit is provided to discharge the member.
Claim 27
Dependent Claim
97 words
An image forming apparatus, comprising: a movable image bearing member on which images can repetitively be formed; means for forming images as electrical charges on the image bearing member; means for affecting the electric charge on the image bearing member, the latter means having a first mode of operation for charging the image bearing member in which a DC charging voltage superimposed with an AC uniforming voltage is applied to the image bearing member, and a second mode operation for discharging the image bearing member in which a charge flow circuit is provided to discharge the member.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.