Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-06-07
2002-06-04
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06398345
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a cleaning technology For removing a powder deposited on a surface to be cleaned, and More specifically to a cleaning technology for removing, with An image forming method and an apparatus for the same for forming an image on an image forming medium by spraying an electrically charged powder as an image forming substance via a powder control member having powder passage holes thereon towards an image forming medium and selectively making the powder flying towards said recording medium pass through said powder passage holes, powder deposited on a surface of said powder control member.
BACKGROUND ART
There has been known an image forming method and an apparatus for the same in which an image forming method called as direct toning or toner projection is employed.
In this image forming method, a voltage based on the image information is applied to the control electrodes placed in a space around slits or minute passage holes provided in the powder control member, charged powder as toner is selectively passed and moved through said powder passage holes to directly inject the toner to an image forming medium such as paper for forming an image.
In an image forming apparatus in which the image forming system as described is employed, when an operation for forming images is continued, sometimes the powder or some foreign material get deposited on a surface of a portion forming the powder passage holes of the powder control member. When the powder or other foreign material get deposited on a surface of the powder control member, jet of the powder flying towards an image forming medium can not be controlled as intended, which results in degradation of the image quality.
To overcome the problem as described above, there have been known various types of cleaning methods as well as cleaning apparatuses for cleaning the surface of the powder control member. For instance, as a cleaning method making use of a mechanical force, there has been known a method in which cleaning is executed by making a rotating brush contact the powder control unit (refer to Japanese Patent Laid-Open Publication No. HEI 3-211064), a method in which cleaning is executed by shaking the powder control member (refer to, for instance, Japanese Patent Laid-Open Publication No. HEI 4-216072), a method in which the powder control member is thermally expanded by heating, and the powder or other foreign material deposited on the member is removed away by making use of deformation of the powder control member (refer to Japanese Patent Laid-Open Publication No. HEI 4-141458), a method in which cleaning is executed by using an air flow (refer to Japanese Patent Laid-Open Publication No. SHO 58-94481, Japanese Patent Laid-Open Publication No. HEI 4-191780, Japanese Patent Laid-Open Publication No. HEI 4-505899, Japanese Patent Laid-Open Publication No. HEI 5-134581), or the like.
As a method in which cleaning is executed by making use of an electromagnetic force, there has been known a method in which an electric field is applied to the charged powder and cleaning is executed by making use of an electrostatic force (a Coulomb force) (refer to Japanese Patent Laid-Open Publication No. SHO 58-96570, Japanese Patent Laid-Open Publication No. SHO 58-104769, Japanese Patent Laid-Open Publication No. SHO 58-104771, Japanese Patent Laid-Open Publication No. SHO 59-188450, Japanese Patent Laid-Open Publication No. SHO 63-123060, Japanese Patent Laid-Open Publication No. HEI
3-168767
, Japanese Patent Laid-Open Publication No. HEI 4-269563, Japanese Patent Laid-Open Publication No. HEI 4-329154, Japanese Patent Laid-Open Publication No. HEI 5-138919).
Also there has been known a method in which the cleaning methods described above are combined. For instance, Japanese Patent Laid-Open Publication No. HEI 5-92608 discloses an image forming apparatus using a magnetic toner as powder and comprising a toner carrier belt as a powder carrier and a rear surface electrode plate provided to hold a control grid as a powder control member via a gap, in which a voltage having a polarity reverse to that of toner is applied to the control grid when an image is not being formed, to promote separation of the deposited toner by an electrostatic force, and also the magnetic toner deposited on a surface of the control grid is removed by rubbing a surface of the control grid with a magnetic brush on the toner carrier belt. Further, for instance, Japanese Patent Laid-Open Publication No. HEI 7-117257 discloses a cleaning method in which toner on a mesh electrode is discharged and removed by simultaneously injecting an air flow and ions to the mesh electrode as a powder control member. Further, for instance, Japanese Patent Laid-Open Publication No. HEI 6-234233 discloses a multi-color image generating apparatus with a toner carrier as a powder carrier and a rear section electrode belt as a counter electrode member provided therein so that the powder control member is held therebetween, in which toner deposited on the powder control member is dropped with a hair-formed pad provided on the rear section electrode belt, and the toner is sucked and recovered through through-holes formed on the rear section electrode belt. Furthermore, for instance, Japanese Patent Laid-Open Publication No. HEI 5-286165 discloses an image forming apparatus with a developing brush roller as a powder carrier and a counter electrode member so that an aperture electrode is held therebetween via a gap, in which toner deposited on the electrode is swung away by vibrating the aperture electrode, and the toner swung away is recovered by an electric field onto the developing brush roller.
It has been turned out, however, that there are various defects in the cleaning methods based on the conventional technology as described above. For instance, in the cleaning method using a brush roller as described above, as the brush roller rotates contacting the powder control member, the powder control member may be damaged, or pulled off brush may get deposited on the developing section or on the powder control member to generate an abnormal image. Also in the cleaning method in which the powder control member is vibrated or the powder control member is thermally deformed to shake off powder, again there is a chance that the powder control member may be damaged, and in addition powder on the powder control member can not be completely removed just by vibrating or deforming the powder control member, and a portion of the powder may remain there in the deposited state. Also the cleaning method using an electromagnetic force can be applied only to a powder which can be magnetized, which is disadvantageous.
As a cleaning method in which an excellent cleaning capability even for non-magnetic powder can be realized without damaging the powder control member, there are the cleaning method using an air flow and the cleaning method using an electrostatic force (a Coulomb force).
However, in the cleaning method using an air flow described above, for completely removing the powder deposited on the powder control member, it is necessary to provide a large-sized fan, a large-sized pump or the like, as a source for generating an air flow, which not only causes an increase in the cost but also generates larger noise due to the fan or the like. In a case of the cleaning method in which an air flow and ions are simultaneously blown to a mesh electrode as a powder control member as disclosed in Japanese Patent Laid-Open Publication No. HEI 7-117257, as toner on the mesh electrode is removed being discharged, it can be considered that the excellent cleaning performance can be obtained even if an air flow is set to a weak level, but a corona-generating apparatus for generating ions is required, and the simplicity, which is one of the advantages features of the direct toning method, is lost.
When it is tried to completely clean off the powder deposited on a powder control member with the cleaning method that makes use of an electrostatic force (a Coulomb force), it is nece
Endo Osamu
Klockar Per
Ohshima Kiyoshi
Ota Kiyotaka
Sakai Katsuo
Gordon Raquel Yvette
McDermott & Will & Emery
Ricoh Co. Ltd.
LandOfFree
Image forming method and an apparatus for the same, and a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image forming method and an apparatus for the same, and a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming method and an apparatus for the same, and a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2973768