Patent EP0376732A2 successfully refreshed from Google Patents.
EP0376732A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Image forming apparatus
Assignee: Canon Inc
•
Filing: 1989-12-28
•
Granted: —
•
Expires: 2009-12-28
Abstract
Abstract An image forming apparatus of the type having a transfer device for transferring images formed on an image carrying member to a transfer material (6) such as a paper sheet. The apparatus comprises an image carrying member (1); a charging device (15) for charging the image carrying member (1); a measuring device (9) for measuring the surface potential of the image carrying member (1); and a transfer device (4) for forming a transfer electric field by means of which images formed on the image carrying member (1) are transferred to a transfer material (6). The measuring device (9) measures the surface potential of the image carrying member (1) when it is charged but is not undergoing image transfer and measures the surface potential of the image carrying member when it is charged and is undergoing image transfer. The transfer electric field formed by the transfer device (4) is controlled on the basis of the measurement results thus obtained by the measuring device.
Inventors
- 👤 Kenichi Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 06:22
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/50; G03G15/5033; G03G15/5037; G03G15/01; G03G15/0105; G03G15/0131; G03G15/14; G03G15/16; G03G15/163; G03G15/1635; G03G15/1645; G03G2215/00; G03G2215/01; G03G2215/0167; G03G2215/0174; G03G2215/0177
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
113 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; and transfer means for transferring images formed on said image carrying member to a transfer material; wherein said measuring means measures the surface potential of said image carrying member when it is charged by said charging means but is not undergoing image transfer, and measures the surface potential of said image carrying member when it is charged by said charging means and is undergoing image transfer, said transfer means being controlled on the basis of the measurement result obtained by said measuring means.
Claim 2
Dependent Claim
113 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; and transfer means for transferring images formed on said image carrying member to a transfer material; wherein said measuring means measures the surface potential of said image carrying member when it is charged by said charging means but is not undergoing image transfer, and measures the surface potential of said image carrying member when it is charged by said charging means and is undergoing image transfer, said transfer means being controlled on the basis of the measurement result obtained by said measuring means.
Claim 3
Dependent Claim
89 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; and transfer means for transferring images formed on said image carrying member to a transfer material; wherein said measuring means measures the surface potential of said image carrying member during a warm-up period before image formation starts; and wherein said transfer means during image formation is controlled on the basis of the measurement result obtained by said measuring means.
Claim 4
Dependent Claim
89 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; and transfer means for transferring images formed on said image carrying member to a transfer material; wherein said measuring means measures the surface potential of said image carrying member during a warm-up period before image formation starts; and wherein said transfer means during image formation is controlled on the basis of the measurement result obtained by said measuring means.
Claim 5
Dependent Claim
92 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; a plurality of developing means which are adapted to develop a toner image onto said image carrying member and which respectively contain toners of different colours; and transfer means for transferring the toner images formed on said image carrying member to a transfer material; wherein said transfer means is controlled on the basis of the measurement result obtained by said measuring means.
Claim 6
Dependent Claim
92 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; a plurality of developing means which are adapted to develop a toner image onto said image carrying member and which respectively contain toners of different colours; and transfer means for transferring the toner images formed on said image carrying member to a transfer material; wherein said transfer means is controlled on the basis of the measurement result obtained by said measuring means.
Claim 7
Dependent Claim
93 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; and transfer means for transferring images formed on said image carrying member to a transfer material; wherein said measuring means measures the surface potential of said image carrying member in a first image forming process for transferring images to said transfer material, and wherein said transfer means is controlled for a second, subsequent image forming process on the basis of the measuring result.
Claim 8
Dependent Claim
93 words
An image forming apparatus comprising: a movable image carrying member; charging means for charging said image carrying member; measuring means for measuring the surface potential of said image carrying member; and transfer means for transferring images formed on said image carrying member to a transfer material; wherein said measuring means measures the surface potential of said image carrying member in a first image forming process for transferring images to said transfer material, and wherein said transfer means is controlled for a second, subsequent image forming process on the basis of the measuring result.
Claim 9
Dependent Claim
53 words
An image forming apparatus as claimed in any one of claims 1 to 4 wherein said transfer means includes means for forming a transfer electric field adapted to transfer the images to the transfer material, the transfer electric field being controlled on the basis of the measurement result obtained by said measuring means.
Claim 10
Dependent Claim
36 words
An image forming apparatus as claimed in claim 5 wherein said transfer electric field is controlled so that the change in surface-potential value of the image carrying member before and after image transfer is substantially constant.
Claim 11
Dependent Claim
51 words
An image forming apparatus as claimed in any previous claim wherein said measuring means comprises a measuring sensor, said measuring sensor being arranged on the upstream side of said transfer means and on the downstream side of said charging means with respect to the moving direction of said image carrying member.
Claim 12
Dependent Claim
50 words
An image forming apparatus as claimed in claim 7 wherein said measuring sensor measures the surface potential of said image carrier when it is charged but is not undergoing image transfer as well as the surface potential of the image carrier when it is charged and is undergoing image transfer.
Claim 13
Dependent Claim
82 words
An image forming apparatus as claimed in any one of claims 1 to 6 wherein said measuring means comprises a first and a second measuring sensor, said first measuring sensor being arranged on the upstream side of said transfer means and on the downstream side of said charging means with respect to the moving direction of image carrier, said second measuring sensor being arranged on the downstream side of said charging means with respect to the moving direction of said image carrier.
Claim 14
Dependent Claim
53 words
An image forming apparatus as claimed in claim 9 wherein said first measuring sensor measures the surface potential of said image carrier when it is charged but is not undergoing image transfer, said second measuring sensor measuring the surface potential of said image carrier when it is charged and is undergoing image transfer.
Claim 15
Dependent Claim
41 words
An image forming apparatus as claimed in any one of claims 1 to 4 wherein said transfer means consists of transfer charges the transfer current of which is controlled on the basis of the measuring result obtained by said measuring means.
Claim 16
Dependent Claim
36 words
An image forming apparatus as claimed in any one of claims 1 to 4 wherein a voltage applied to said transfer means is controlled on the basis of the measuring result obtained by said measuring means.
Claim 17
Dependent Claim
54 words
An image forming apparatus as claimed in any one of claims 1 to 4 wherein a transfer electric field is formed by said transfer means and is controlled in such a manner that the change in the surface potential is kept constant on the basis of the measuring result obtained by said measuring means.
Claim 18
Dependent Claim
29 words
An image forming apparatus as claimed in claim 13 wherein the transfer electric field is intensified when the change in said surface potential is smaller that a predetermined value.
Claim 19
Dependent Claim
29 words
An image forming apparatus as claimed in claim 13 wherein the transfer electric field is attenuated when the change in said surface potential is larger than a predetermined value.
Claim 20
Dependent Claim
36 words
An image forming apparatus as claimed in claim 2 wherein said measuring means measures the surface potential of said image carrying member when it is charged by said charging means but is not undergoing image transfer.
Claim 21
Dependent Claim
66 words
An image forming apparatus as claimed in any previous claim further comprising fixing means for fixing toner images upon said transfer material, wherein toner images of different colours are formed upon said transfer material, one superimposed upon the other, by said transfer means, said fixing means mixing the toners of different colours with each other in the process of fixing the images upon said transfer material.
Claim 22
Dependent Claim
57 words
An image forming apparatus as claimed in any previous claim further comprising a plurality of image forming sections each of which includes at least said image carrying member, said charging means and said transfer means, images of different colours being formed in said image forming sections by superimposing one image upon the other on said transfer material.
Claim 23
Dependent Claim
29 words
An image forming apparatus as claimed in claim 18, wherein the number of said image forming sections is four, in correspondence with the colours: yellow, magenta, cyan and black.
Claim 24
Dependent Claim
40 words
An image forming apparatus as claimed in any previous claim further comprising a transfer drum adapted to absorb said transfer material, images being formed upon said transfer material, with one being superimposed upon the other, by rotating said transfer drum.
Claim 25
Dependent Claim
56 words
A copier of the kind in which an electrostatic latent-image is formed on a photosensitive image carrying member by means of a surface potential created on the image carrying member is characterised in that there are means for controlling the surface potential of the image carrying member in response to changes in temperature and relative humidity.
Claim 26
Dependent Claim
56 words
A copier of the kind in which an electrostatic latent-image is formed on a photosensitive image carrying member by means of a surface potential created on the image carrying member is characterised in that there are means for controlling the surface potential of the image carrying member in response to changes in temperature and relative humidity.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.