CA1198765A - Apparatus, process for charging insulating toner particles - Google Patents
Apparatus, process for charging insulating toner particlesInfo
- Publication number
- CA1198765A CA1198765A CA000405757A CA405757A CA1198765A CA 1198765 A CA1198765 A CA 1198765A CA 000405757 A CA000405757 A CA 000405757A CA 405757 A CA405757 A CA 405757A CA 1198765 A CA1198765 A CA 1198765A
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- CA
- Canada
- Prior art keywords
- toner particles
- charge
- accordance
- roller
- injecting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
- G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
- G03G15/0812—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller characterised by the developer regulating means, e.g. structure of doctor blade
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2215/00—Apparatus for electrophotographic processes
- G03G2215/06—Developing structures, details
- G03G2215/0634—Developing device
- G03G2215/0636—Specific type of dry developer device
- G03G2215/0641—Without separate supplying member (i.e. with developing housing sliding on donor member)
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Dry Development In Electrophotography (AREA)
- Developing Agents For Electrophotography (AREA)
Abstract
ABSTRACT
This invention is generally directed to an improved apparatus and an improved process for charging insulating toner particles to either a positive or negative polarity, and an electrostatographic imaging system containing such apparatus, the apparatus including a means for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting, and the means for injecting, being charged to a predetermined potential. More specifically, in one embodiment the apparatus of the present invention is comprised of a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, and a voltage source means for said roller means, wherein charges are injected from said charge injecting means into the uncharged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encom-passed by said roller means and said charge injecting means. The process of the present invention comprises providing uncharged insulating toner particles on a means for transporting said particles, followed by contacting the particles with a means for injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential, wherein charges are injected into the uncharged insulating toner particles. Subsequently, the charged insulating toner particles can be deposited on an imaging member containing an image thereon.
This invention is generally directed to an improved apparatus and an improved process for charging insulating toner particles to either a positive or negative polarity, and an electrostatographic imaging system containing such apparatus, the apparatus including a means for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting, and the means for injecting, being charged to a predetermined potential. More specifically, in one embodiment the apparatus of the present invention is comprised of a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, and a voltage source means for said roller means, wherein charges are injected from said charge injecting means into the uncharged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encom-passed by said roller means and said charge injecting means. The process of the present invention comprises providing uncharged insulating toner particles on a means for transporting said particles, followed by contacting the particles with a means for injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential, wherein charges are injected into the uncharged insulating toner particles. Subsequently, the charged insulating toner particles can be deposited on an imaging member containing an image thereon.
Description
6~
APPARATUS, PROCESS FOR CHARGIN~ INSULATING TON~R PARTICLES
BACKGRC)UND OF THE INVENTION
This invention is generally directed to an irnproved apparatus, and an improved process for charging insulating toner particles. More specifically, the present invention is direeted to an improved apparatus for charging insulating toner particles to an appropriate charge level, and a desired charge polarity~ that is, either positive or negative, utilizing a charge injecting electrode. The resulting charged toner particles can be utilized as single component developers, that is, developers containing no carrier particles, for developing images in electrostatographic imaging systems.
The formation and development of electrostatographic images, and more specifically xerographic images, is well known in the art as described for example in U. S. Patent 2,297,691. In one known method for causing the development of such images, a developer composition comprised of toner particles and carrier particles is cascaded over an image bearing member, wherein the toner particles which are triboelec~rically charged to a certain polarity and magnitude deposit in regions of the imaging surface where there is a preponderence of charge of opposite polarity. In another form of development known as magnetic brush development, magnetic carriers are employed, reference IJ. S. Patent 3,641,980, ~vherein magnetic forces are employed for the purpose of causing toner particles to deposit on the imaging member. In addition to providing for the superior development of solid image areas, magnetic brush development systems are more compact than cascade development systems, and do not depend on gravity for causing the toner particles to deposit on the imaging member surface, a factor which allows more freedom in locating the developer station.
In developer mixtures used in conventional cascade development systems, there is a triboelectric charging relationship between the toner particles and the carrier particles, thus ~or example, the toner particles are charged negatively, and the carrier particles are charged positively, accord-ingly, positively and negatively charged images cannot easily be rendered visible with the same developer. Also, the triboelectric properties of the toner composition while necessary for development can cause problerns, for example, uneven charging of the toner causes background deposits, as the forces between the carrier and toner particles result in various threshold levels from toner particle to toner particle. Further, since the toner particlesretain their charge for extended periods of time, any toner that escapes the development ~one and enters into other parts of the electrostatographic apparatus can eause mechanical problems. While magnetic brush development 5 overcomes some of the problems encountered with cascade development, it is in some instances less efficient in that it requires triboelectrically charged toners.
There has also been described in the prior art magnetic develop-ment systems and materials wherein carrier particles are not utilized, that is, one component developer compositions. One such system is described in U. S.
Patent 2,846,333, which patent diseloses the use of a magnetic brush to apply toner particles formed of magnetite and resin materials. One difficulty encountered with this process is that the relatively high electrical con-ductivity of the toner partieles renders electrostatic transfer rather difficult.
15 ~lso there is described in U. S. 3,909,258 electrostatic development utili~ing magnetic brush and no carier particles. The developing composition used in such systems is comprised of toner particles, reference U.S. 3,639,245. One d;sadvantage of such a toner composition is that it does not transfer efficiently from a photoconductive substrate to plain bond paper.
Most single component development systerns eontrol background deposition with magnetic forces, and as such forces are generally weaker than eleetrostatic forces, background development from single component systerns is typically inferior to electrosta$ic systems employing two component developer compositions. Additionally, many single component development 25 systems use conductive toner eharged by induetion, however, conductive toner usually requires special papers and the like.
The utilization of insulating toner particles is thus important for background control, and also such particles can be transferred rather efficiently and effeetively from a photoresponsive surface to plain paper.
30 While many different suitable methods are known for eharging toner particles,there continues tc be a need for an effective simple method for charging insulati7re toner particles, to a desired charge magnitude and a desired positive or negative charge polarity.
Other development methods include powder cloud development as 35 described in U. S. Patent 2,217,776 and touchdown development as described inU. S. Patent 3,166,432. In the '432 patent there is disclosed the use of a 3r7i5i conductive c~ne component developer (toner and no carrier particles) for developing electrostatic charge patterns by bringing a conductive support member containing a layer of conductive toner particles into contact with the charge pattern. The toner particles are held to the support member primarily by Vander Waals forces, and the conductive support is maintained at a biased potential during develop-ment.
SUMMARY OF THE lNv~NllON
It is a feature of an aspect of the present inven-tion to provide an apparatus and process for charging insulative toner particles.
A feature of an aspect of the present invention is the provision of an improved apparatus and improved process for charging insulative uncharged toner particles utilizing a charging electrode~
A feature of an aspect of the present invention is the provision of a process for charging uncharged toner particles to a positive polarity, or a negative polarity.
2Q A feature of an aspect of the present invention is the provision of a process for charging insulative tone;
particles while simultaneously controlling background drvelopment7 and providing for the efficient and ef~ectjve transfer of such toner particles from an image bearing surface to plain paper.
These and ot~er ~eatures o~ the present invention are general~y accomplished by the provision o~ an improved process and an improved apparatus for charging insulating toner particles, which comprises providing in operative relationship ~ ton~r supply means, a roller means contain-ing thereon uncharged insulating toner particles, a charge injection means in close proximity to the roller means~ and self-spaced from said roller means by insulating toner particles, a voltage means or the charge injection ~4--means, and a voltage means for the roller means. The roller means generally contains a coating thereon as indi-cated hereinO
In one embodim~nt, the presen~ invention is direct-ed to an improved apparatus for charging uncharged insulating toner particles, which apparatus comprises in operative relationship a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for the charge injecting means, and a voltage source means for the roller means, wherein charges are injected from the charge injecting means into the uncharged insula-ting toner particles deposited on the roller means, the injection being accomplished in a charging zone encompassed by the roller means and the charge injecting means.
In another embodiment the pre~ent invention is directed to a process for charging insulating uncharged toner particles contained on a roller means, to a positive or negative polarity by injecting the appropriate charges thereon, or therein from charges originating from a charge injecting electrode means which contacts toner particles contained in a zone between the roller means and the electrode means, the polarity of the charges contained on the insulating toner particles being dependent on the polarity of the charges supplied to the charging electrode by a voltage source means. The thus charged insulating toner particles can be employed in electrostatographic imaging systemsr particularly xerographic imaging systems.
Accord_ngly, in accordance with the process o~ the present invention and the apparatus thereof, toner particles can be charged to the desired polarity without the utilization of carrier particles as is customarily practiced in the prior art.
-4a~
In accordance with another feature of the present invention, there is provided an improved electrostato-graphic imaging apparatus comprising a charging means, an imaging means, a development means, a transfer means, a fusing means, an optical cleaning means and a fixing means, the improvement residing in the development means which comprise in operative relationship a roller means, containing a coating thereon, a toner supply means contain-ing therein uncharged insulating toner particles, a charge injecting means, a voltage sou.rce means~ for said charge injecting means, a voltage source means for said roller means, wherein charges are injected from said charge inject-ing means into the uncharged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encompassed by said roller means and said charge injecting means, and wherein the resulting charged insulating toner particles are deposited on an imaging member.
Other aspects of this invention are as follows:
An improved apparatus for charying uncharged insu-lating toner particles which apparatus comprises an opera-tive relationship a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, a voltage source means for said roller means, wherein charges are injected from said charge injecting means into the un-charged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encom-passed by said roller means and said charge injecting meansO
An improved electrostatographic imaging apparatuscomprising a charging means, an imaging means, a develop-ment means, a tranfer means., a fusing means, and a fixing means, the improvement residing in the development means r -~b-which comprises in operative relationship a roller means containing a coating thereon, a toner supply means con^tain~
ing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, and a voltage source means for said roller means, wherein charges are injected from said charge inject-ing means into uncharged insulating toner particles deposit-ed on said roller means, said injection accomplished in a charging 7one encompassed b~ said roller means and said charge injecting means, and wherein the resulting charged insulating toner particles are deposited on an imaging member contained in said imaging apparatus.
An improved process for charging ~mcharged insula-ting toner particles which comprises providing uncharged insulating toner particles on a roller con~aining a coating thereon, contacting said toner particles with a charge injecting electrode, in a charging ~one encompassed by said roller and said injecting electrode, providing a voltage source for said charge injecting electrode, and providing a voltage source for said rollerJ whc~rein charges are injected into the uncharged insulating toner particles.
An improved apparatus ~or charging insulating toner particles comprised in operative relationship of a means for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential.
An improved electrostatographic imaging apparatus comprising a charging means, an imaging means~ a develop-ment means, a trans~er meansr a ~using means7 and a fixingmeans, the improvement residing in the development means which comprises in operative relationship a means for transporting insulating toner particles, and a means for ~ ! \
s ~4c~
injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential, wherein the result-ing charged insulating toner particles are deposited on an imaging member contained in said imaging apparatus.
An improved process for charging insulating toner particles which comprises providing uncharged insulating toner particles on a transporting means, contacting said insulating toner particles with a means for injecting charges into the insulating toner paxticlesr the means for transporting and 1-he means for injecting being charged to a predetermined potential r wherein charges are injected into the uncharged insulating toner particles.
DEgCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention and various alternative embodiments thereof will now be described with reference to the Figures wherein:
Figure l is an elevational view illustrating the development apparatus and development process of the present invention.
Figure 2 illustrates t~e use of the apparatus and process of the present invention in a conventional electro-statographic imaging system.
.,., .
., ,, ~ .
7~S
Illustrated in Figure 1 is the apparatlls and process of the present invention generally designated 7 comprising an imaging member means 10, a roller means 12, containing thereon coating 13, toner supply reservoir means 14,containing therein uncharged insulating toner particles 24, a charging electrode means 16, a pressure blade means 17, a voltage source means 18, a voltage source means 20, and charging zone 19. The uncharged insulating toner particles 24 are metered onto the roller means 12 as the roll moves in the direction illlJstrated by the arrow, the amount of toner partieles being depos;ted on said roll dependent primarily on the spacing between the toner supply reservoir 14 and roller 12. ~he toner supply resersloir thus functions similar to a doctor blade and is maintained at a specific angle and at a sufficient pressure so as to provide uncharged insulating toner particles on theroller means 12 in a thickness of from about 0.5 mils to about 2 mils, and preferably from about 0.5 mils to about 1 mil, or preferably about 1 layer of toner particles. The insulating toner particles are adhered to the roller means 12 by electrostatic attraction forces, the roller being caused to rotate by a motor not shown. As the insulating toner particles 24 migrate on the roller means 12, they eventually contact the charge injecting electrode means 16 in charging zone 19 wherein charges of a positive polarity as illustrated, or a
APPARATUS, PROCESS FOR CHARGIN~ INSULATING TON~R PARTICLES
BACKGRC)UND OF THE INVENTION
This invention is generally directed to an irnproved apparatus, and an improved process for charging insulating toner particles. More specifically, the present invention is direeted to an improved apparatus for charging insulating toner particles to an appropriate charge level, and a desired charge polarity~ that is, either positive or negative, utilizing a charge injecting electrode. The resulting charged toner particles can be utilized as single component developers, that is, developers containing no carrier particles, for developing images in electrostatographic imaging systems.
The formation and development of electrostatographic images, and more specifically xerographic images, is well known in the art as described for example in U. S. Patent 2,297,691. In one known method for causing the development of such images, a developer composition comprised of toner particles and carrier particles is cascaded over an image bearing member, wherein the toner particles which are triboelec~rically charged to a certain polarity and magnitude deposit in regions of the imaging surface where there is a preponderence of charge of opposite polarity. In another form of development known as magnetic brush development, magnetic carriers are employed, reference IJ. S. Patent 3,641,980, ~vherein magnetic forces are employed for the purpose of causing toner particles to deposit on the imaging member. In addition to providing for the superior development of solid image areas, magnetic brush development systems are more compact than cascade development systems, and do not depend on gravity for causing the toner particles to deposit on the imaging member surface, a factor which allows more freedom in locating the developer station.
In developer mixtures used in conventional cascade development systems, there is a triboelectric charging relationship between the toner particles and the carrier particles, thus ~or example, the toner particles are charged negatively, and the carrier particles are charged positively, accord-ingly, positively and negatively charged images cannot easily be rendered visible with the same developer. Also, the triboelectric properties of the toner composition while necessary for development can cause problerns, for example, uneven charging of the toner causes background deposits, as the forces between the carrier and toner particles result in various threshold levels from toner particle to toner particle. Further, since the toner particlesretain their charge for extended periods of time, any toner that escapes the development ~one and enters into other parts of the electrostatographic apparatus can eause mechanical problems. While magnetic brush development 5 overcomes some of the problems encountered with cascade development, it is in some instances less efficient in that it requires triboelectrically charged toners.
There has also been described in the prior art magnetic develop-ment systems and materials wherein carrier particles are not utilized, that is, one component developer compositions. One such system is described in U. S.
Patent 2,846,333, which patent diseloses the use of a magnetic brush to apply toner particles formed of magnetite and resin materials. One difficulty encountered with this process is that the relatively high electrical con-ductivity of the toner partieles renders electrostatic transfer rather difficult.
15 ~lso there is described in U. S. 3,909,258 electrostatic development utili~ing magnetic brush and no carier particles. The developing composition used in such systems is comprised of toner particles, reference U.S. 3,639,245. One d;sadvantage of such a toner composition is that it does not transfer efficiently from a photoconductive substrate to plain bond paper.
Most single component development systerns eontrol background deposition with magnetic forces, and as such forces are generally weaker than eleetrostatic forces, background development from single component systerns is typically inferior to electrosta$ic systems employing two component developer compositions. Additionally, many single component development 25 systems use conductive toner eharged by induetion, however, conductive toner usually requires special papers and the like.
The utilization of insulating toner particles is thus important for background control, and also such particles can be transferred rather efficiently and effeetively from a photoresponsive surface to plain paper.
30 While many different suitable methods are known for eharging toner particles,there continues tc be a need for an effective simple method for charging insulati7re toner particles, to a desired charge magnitude and a desired positive or negative charge polarity.
Other development methods include powder cloud development as 35 described in U. S. Patent 2,217,776 and touchdown development as described inU. S. Patent 3,166,432. In the '432 patent there is disclosed the use of a 3r7i5i conductive c~ne component developer (toner and no carrier particles) for developing electrostatic charge patterns by bringing a conductive support member containing a layer of conductive toner particles into contact with the charge pattern. The toner particles are held to the support member primarily by Vander Waals forces, and the conductive support is maintained at a biased potential during develop-ment.
SUMMARY OF THE lNv~NllON
It is a feature of an aspect of the present inven-tion to provide an apparatus and process for charging insulative toner particles.
A feature of an aspect of the present invention is the provision of an improved apparatus and improved process for charging insulative uncharged toner particles utilizing a charging electrode~
A feature of an aspect of the present invention is the provision of a process for charging uncharged toner particles to a positive polarity, or a negative polarity.
2Q A feature of an aspect of the present invention is the provision of a process for charging insulative tone;
particles while simultaneously controlling background drvelopment7 and providing for the efficient and ef~ectjve transfer of such toner particles from an image bearing surface to plain paper.
These and ot~er ~eatures o~ the present invention are general~y accomplished by the provision o~ an improved process and an improved apparatus for charging insulating toner particles, which comprises providing in operative relationship ~ ton~r supply means, a roller means contain-ing thereon uncharged insulating toner particles, a charge injection means in close proximity to the roller means~ and self-spaced from said roller means by insulating toner particles, a voltage means or the charge injection ~4--means, and a voltage means for the roller means. The roller means generally contains a coating thereon as indi-cated hereinO
In one embodim~nt, the presen~ invention is direct-ed to an improved apparatus for charging uncharged insulating toner particles, which apparatus comprises in operative relationship a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for the charge injecting means, and a voltage source means for the roller means, wherein charges are injected from the charge injecting means into the uncharged insula-ting toner particles deposited on the roller means, the injection being accomplished in a charging zone encompassed by the roller means and the charge injecting means.
In another embodiment the pre~ent invention is directed to a process for charging insulating uncharged toner particles contained on a roller means, to a positive or negative polarity by injecting the appropriate charges thereon, or therein from charges originating from a charge injecting electrode means which contacts toner particles contained in a zone between the roller means and the electrode means, the polarity of the charges contained on the insulating toner particles being dependent on the polarity of the charges supplied to the charging electrode by a voltage source means. The thus charged insulating toner particles can be employed in electrostatographic imaging systemsr particularly xerographic imaging systems.
Accord_ngly, in accordance with the process o~ the present invention and the apparatus thereof, toner particles can be charged to the desired polarity without the utilization of carrier particles as is customarily practiced in the prior art.
-4a~
In accordance with another feature of the present invention, there is provided an improved electrostato-graphic imaging apparatus comprising a charging means, an imaging means, a development means, a transfer means, a fusing means, an optical cleaning means and a fixing means, the improvement residing in the development means which comprise in operative relationship a roller means, containing a coating thereon, a toner supply means contain-ing therein uncharged insulating toner particles, a charge injecting means, a voltage sou.rce means~ for said charge injecting means, a voltage source means for said roller means, wherein charges are injected from said charge inject-ing means into the uncharged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encompassed by said roller means and said charge injecting means, and wherein the resulting charged insulating toner particles are deposited on an imaging member.
Other aspects of this invention are as follows:
An improved apparatus for charying uncharged insu-lating toner particles which apparatus comprises an opera-tive relationship a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, a voltage source means for said roller means, wherein charges are injected from said charge injecting means into the un-charged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encom-passed by said roller means and said charge injecting meansO
An improved electrostatographic imaging apparatuscomprising a charging means, an imaging means, a develop-ment means, a tranfer means., a fusing means, and a fixing means, the improvement residing in the development means r -~b-which comprises in operative relationship a roller means containing a coating thereon, a toner supply means con^tain~
ing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, and a voltage source means for said roller means, wherein charges are injected from said charge inject-ing means into uncharged insulating toner particles deposit-ed on said roller means, said injection accomplished in a charging 7one encompassed b~ said roller means and said charge injecting means, and wherein the resulting charged insulating toner particles are deposited on an imaging member contained in said imaging apparatus.
An improved process for charging ~mcharged insula-ting toner particles which comprises providing uncharged insulating toner particles on a roller con~aining a coating thereon, contacting said toner particles with a charge injecting electrode, in a charging ~one encompassed by said roller and said injecting electrode, providing a voltage source for said charge injecting electrode, and providing a voltage source for said rollerJ whc~rein charges are injected into the uncharged insulating toner particles.
An improved apparatus ~or charging insulating toner particles comprised in operative relationship of a means for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential.
An improved electrostatographic imaging apparatus comprising a charging means, an imaging means~ a develop-ment means, a trans~er meansr a ~using means7 and a fixingmeans, the improvement residing in the development means which comprises in operative relationship a means for transporting insulating toner particles, and a means for ~ ! \
s ~4c~
injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential, wherein the result-ing charged insulating toner particles are deposited on an imaging member contained in said imaging apparatus.
An improved process for charging insulating toner particles which comprises providing uncharged insulating toner particles on a transporting means, contacting said insulating toner particles with a means for injecting charges into the insulating toner paxticlesr the means for transporting and 1-he means for injecting being charged to a predetermined potential r wherein charges are injected into the uncharged insulating toner particles.
DEgCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention and various alternative embodiments thereof will now be described with reference to the Figures wherein:
Figure l is an elevational view illustrating the development apparatus and development process of the present invention.
Figure 2 illustrates t~e use of the apparatus and process of the present invention in a conventional electro-statographic imaging system.
.,., .
., ,, ~ .
7~S
Illustrated in Figure 1 is the apparatlls and process of the present invention generally designated 7 comprising an imaging member means 10, a roller means 12, containing thereon coating 13, toner supply reservoir means 14,containing therein uncharged insulating toner particles 24, a charging electrode means 16, a pressure blade means 17, a voltage source means 18, a voltage source means 20, and charging zone 19. The uncharged insulating toner particles 24 are metered onto the roller means 12 as the roll moves in the direction illlJstrated by the arrow, the amount of toner partieles being depos;ted on said roll dependent primarily on the spacing between the toner supply reservoir 14 and roller 12. ~he toner supply resersloir thus functions similar to a doctor blade and is maintained at a specific angle and at a sufficient pressure so as to provide uncharged insulating toner particles on theroller means 12 in a thickness of from about 0.5 mils to about 2 mils, and preferably from about 0.5 mils to about 1 mil, or preferably about 1 layer of toner particles. The insulating toner particles are adhered to the roller means 12 by electrostatic attraction forces, the roller being caused to rotate by a motor not shown. As the insulating toner particles 24 migrate on the roller means 12, they eventually contact the charge injecting electrode means 16 in charging zone 19 wherein charges of a positive polarity as illustrated, or a
2~ negative polarity not illustrated, are injeeted into the toner particles;
accordingly, the toner partieles exiting from the charging zone 19 contain thereon positive charges 24'. The charging electrode means 16 is self-spaced from the roller means 12 by the toner particles situated therebetween, and the voltage source, 18, Vc, supplies the charge to the electrode 16, which charge inthe embodiment shown is of a positive polarity. The positively charged toner particles continue to migrate on the roller means 12~ until they contact the latent image contained on the imaging member means 10, wherein they are electrostatically attracted to the image, causing development. Unused charged toner particles are returned to the toner supply reservoir 14 on the roller means 12 as shown. The doctor blade 17 provides sufficient pressure to the imaging member means 10 so as to cause said imaging mermber means to be in constant contact with the charged insulating toner particles as shown.
Voltage, 20, VB, also assists in providing for attraction between the charged toner particles and the image contained on the imaging member 10.
An important feature of the present invention resides in the charging electrode means 16, which electrode injects positive charges, or negative charges into the insulating toner particles 24 contained on the roller means 12. The polarity of the charge, and the magnitude of charge injected is controlled by the voltage source Vc 18, thus if a positive polarity is desired on the toner particles, a positive voltage source is applied to the inJecting 5 contact means 16, while if a negative polarity is desired on the insulating toner particles, a negative voltage Vc is applied to the charging electrode means 16.
Charges of the appropriate polarity and magnitude are injected into and accepted by the insulating toner particles as a result of the contact between such particles and the injecting electrode means 16, which is self-spaced from 10 the roller means 1~ by the insulating toner particles situated in the charging zone 19. As indicated herein, generally only one layer of toner particles is contained on the roller means 12, although less or more than one layer of toner particles can be present on rol1er 12, however, if several layers of uncharged toner particles are contained on the roller means 12, difficulties can be 15 encountered in completely charging all the layers of toner particles, since the charge being injected by the electrode 16 cannot usually penetrate more than a few layers of toner particles. The resulting charged insulating toner particles can easily be transferred to plain bond paper subsequent to development as contrasted with conductive toner particles which contain conducting agents 20 therein, and are very difficult to transfer to plain bond paper.
The roller means 12 is comprised of a core which can be hollow or solid and is comprised of numerous known suitable materials including for example, aluminum, steel, iron, polymeric materials, ~md the like~ providing they are of sufficient strength to be operable in the system, with the preferred25 core material being aluminum. (~enerally, this roll has a diameter of from about 1 inch to about 3 inches and preferably has a diameter of from 1 inch to 2inches. This roll can be of a larger or small diameter providing it accom-plishes the objectives of the present invention.
The roller means 12 contains thereon a resistive textured coating 30 layer 13 such as aluminized ~aylar overcoated with carbon black, Krylo~ultra flat black paint, commercially available as Krylon 1602, and various other similar resistive materials. The thiclcness of the coatin@; can vary over a widerange and is dependent on many factors including economical considerations, however, generally the thickness of this coating is from about 0.1 mils to about35 5 mils and preferably is from about 1 mil to about 3 mils. While it is not desired to be limited by theory~ it is believed that the coating assists in c~ rk5 ~a~
increasing the efficiency of charge injection from the charge injecting electrode 16, in that for example, negative charges, which would tend to neutrali~e the positive charges of the charged toner particles contained on the charging roll 12 are prevented from being attracted to the positively charged 5 toner particles. Similarly, when a negative charge is injected into the insulating toner particles, a corresponding positive charge results on the roller means 12, and it is desired to prevent such a charge from migrating to the negatively charged toner particles.
The amount of charge applied to the uncharged insulating toner 10 particles is primarily dependent on the voltage source 18 Vc, which charge generally ranges from about lûO volts to about 500 volts3 and preferably from about 200 volts to about 300 volts when a positive polarity is desired on the insulating uncharged toner particles. When a negative polarity is desired on the uncharged insulating toner particles, the voltage Vc 18 is from about a -10015 volts to about a-500 volts, and preferably erom about a -200 volts to about a -300 volts.
The charge injected into the uncharged toner particles is not onl~J
dependent on the voltage source 18 Vc but on a number of other factors including for e~ample, the number of layers of particles charged, the material 20 utilized as coating 13, and the like. lIowever, generally the uncharged tonerparticles acquire a charge of from about 10 microcoulombs per ~ram to about 35 microcoulombs per gram, and preferably from about 11) microcoulombs per gram to about 20 microcoulombs per gram. Such toner particles are thus of sufficient conductivity so as to be attracted to the image contained on the 25 imaging member means 10, but yet sufficiently insulating in order that they may be easily transferable to plain bond paper.
The voltage source 20, VB, which is primarily employed for background control in the image areas in that it prevents deposition of the charged insulating toner particles in the background areas ranges from about 30 -75 volts to about -200 volts and preferably ranges from about a -75 volts to about a -150 volts.
The injecting eleetrode means 16 can be comprised of various suitable materials providing it is capable Oe accepting charge from the voltage source 18 Vc, and furthera such electrode means 16 should be comprised of a 35 material that will enable the injection of positive or negative charges erom the injecting source means 16 into the uncharged insulating toner particles in 7~i5 accordance with the features of the present invention. C~enerally, the injecting or ~harging electrode can be comprised of metallic substances such as aluminum, steel, iron and the like, with aluminum being preferred. The eharging electrode means 16 is usually not maintained in a fixed position, 5 rather it generally contains thereon a foam backing which is not shown7 so as to allow it to contact the roller means 12, which contact is usually prevented by the layer of insulating uncharged toner particles contained between the charge injecting means 16 and the roller means 12. Thus, the charging electrode means 16 is self-spaced from the roller means 12, such self-spacing 10 being dependent on the number of layers of toner particles contained in the charging zone l9. The length of the charging zone 19 ean vary providing the objectives of the present invention are accomplished, generally however, this length is from about 5 millimeters to about 30 millimeters9 and preferably from about lD millimeters to about 20 millimeters.
The direction of movement of the roller means 12 and the imaging member means 10 can be as shown, that is, in the same direction, or in a dire~tion opposite to each other, that is, roUer 12 can move in the direction opposite to that of the direction of movement of imaging member means 10.
~enerally, roller means 12 is moving at a rate o speed that is faster than the 20 rate of speed OI movement of the irnaging member means 10, thus the speed ratio of the charging roll 12 to the imaging member means 10 varies from about 4 to about 1 and is preferably from about 2 to about 3. Accordingly thus, in this embodiment, the roller 12 is moving at a higher speed (d~) than the speed of the imaging member means 11~.
The pressure blade 17 can be comprised of numerous suitable materials including plastics, nylon, steel, aluminum and the like with the forcebeing exerted by such blade being of sufficient value so as to maintain the imaging member 10 in contact with the charged insulflting toner particles, such force ranging generally from about 0.3 pounds per inch to about 3 pounds per 30 inch and preferably from about 0.5 pounds per inch to about 1 pound per inch.The process and apparatus of the present invention can be utilized in various imaging systems including electrostatic latent imaging systems as shown for example in Figure 2. In Figure 2 there is illustrate~ a xerographic imaging system employing an imaging member 1, which corresponds to the 35 imaging member 10 of Figure 1. In this embodiment of the present invention the imaging member 1 can be comprised of a substrate, overcoated with a 3r7~j _9_ transport layer containing N,~,N',N'-tetraphenyl-[l,lt-biphenyl] ~4'-diamine, or similar diamines dispersed in a polycarbonate, which in turn is overcoated with a generating layer of trigonal selenium. Imaging member 1 moves in the direction of arrow 27 to advance successive portions of the imaging member 5 sequentially through the various processing stations disposed about the path of movement thereof. The imaging member is entrained about a sheet-stripping roller 2~, tensioning means 29, and drive roller 30. Tensioning means 29 includes a roller 31 having Ilanges on opposite sides thereo~ to define a path through which member 1 moves, with roller 31 being mounted on each end of 10 guides attached to springs. Spring 32 is tensioned such that roller 31 presses against the imaging belt member 1. In this manner, member 1 is placed under the desired tension. The level of tension is relatively low permitting member 1 to be easily deformed. With continued reference to Figure 2, drive roller 30 is mounted rotatably and in engagement with member 1. Motor 33 rotates r oller 15 30 to advance member 1 in the direction of arrow 27. Roller 30 is coupled to motor 33 by suitable means such as a belt drive. Sheet-stripping roller 2g is freely rotatable so as to readily permit member 1 to move in the direction of arrow 27 with a minimum of friction.
Initially, a portion of imaging member 1 passes through charging 2~ station H. At charging station H, a eorona generating device, indicated generally by the reference numeral 34, charges the photoconductive surface of imaging member 1 to a relatively high, substantially uniform potential.
The charged portion of the photoconductive surface is then advanced through exposure station I. An original document 35 is positioned 25 face down upon transparent platen 36. Lamps 37 flash light rays onto originaldocument 35, and the light rays reflected from original document 35 are transmitted through lens 38 forming a light image thereof. Lens 3~ fc~cuses the light image onto the charged portion of the photoconductive surface to selectively dissipate the charge thereon. This records an electrostatic latent 30 image on the photoconductive surface which corresponds to the informational areas contained within original document 35.
Thereafter, imaging member 1 advances the electrostatic latent image recorded thereon to station J wherein it is contacted with positively charged insulating toner particles 24', station J including a roller means 12, 35 coating 13, a charging injecting means 16, a toner supply reservoir 1~, pressur bladel7, charging zone 19, and insulating toner particles 24. The details of the ~3~ 5 -ln charging of the toner particles and deposition thereon on the imaging member are illustrated with reference to Figure 1.
Imaging member 1 then advances the toner powder image to transfer station K. At transEer station K, a sheet of support maierial 44 is 5 moved into contact with the ts~ner powder image. The sheet of support material 44 is advanced to transfer station K by a sheet feeing apparatus (not shown)O Preferably, the sheet feeding apparatus includes a feed roll contacting the uppermost sheet of a stack of sheets. The feed roll rotates so as to advance the uppermost sheet from the stack into a chute, which chute directs 10 the advancing sheet of support material into contact with the photoconductivesurface of member 1 in a timed sequence in order that the toner powder image developed thereon contacts the advancing sheet of support material at transfer station K.
Transfer station K incluc!es a corona generating device 46 which 15 sprays ions onto the backside of sheet 44, allowing for the attraction of the torler powder image from the photoconductive surface to sheet 44. After transfer, sheet 44 moves in the direction of arrow 48 onto a conveyor (not shown) which advances sheet 44 to fusing station L.
Fusing station L includes a fuser assembly, indicated generally by 20 the reference numeral S0, which permanently affixes the transferred toner powder image to sheet 44. Preferably, fuser assembly 50 includes a heated fuser roller 52 and a back-up roller 54. Sheet 44 passes between fuser`roller 52 and back-up roller 54 with the toner powder image contacting fuser roller 52. In this mannerl the toner powder image is permanently affixed to sheet 25 44~ After fusing, a chute guides the advancing sheet 44 to a catch tray for subsequent removal from the printing machine.
Invariably, after the sheet of support material is separated from the photoconductive surface of imaging member 1 some residual particles remain adhering thereto. These residual particles are removed from the 30 photoconductive surface at cleaning station M. Cleaning station L includes a rotatably mounted fibrous brush 56 in contact with the photoconducti-le surface. The particles are cleaned from the photoconductive surface by the rotation of brush 56 in contact therewith. Subsequent to cleaning, a discharge lamp (not shown) floods photoconductive surface 12 with light to dissipate any 35 residual electrostatic charge remaining thereon prior to the charging thereof for the next successive imaging cycle.
'7g~
It is believed that the foregoing description is suff icient for purposes of the present invention to illustrate the general operation of an electrophotographic printing machine incorporating the features of the present invention therein.
nlustrative examples of the imaging member 1 or 1~1 includes inorganic and organic photoresponsive materials such as a~orphous selenium, selenium alloys, including alloys of selenium-tellurium, selenium arsenic, selenium antimony, selenium-tellurium-arsenic, cadmium sulfide, zinc oxide, polyvinylcarbazole, layered organic photoreceptors, such as those containing as an injecting contact, carbon dispersed in a polymer, overcoated with a transport layer, which in turn is overcoated with a generating layer, and finally an overcoating of an insulating organic resin, reference U.S. Patent 4,251,612, overcoated layers comprised of a substrate, a charge transport layer,and a charge generating layer, reference U.~. Patent 4,265,990 and the like.
Other organic photoreceptor materials include, ~dimethyl-aminobenzylidene, ben2hydrazide; 2-benzylidene-amino-carbazole, 4-dimethyl-amino-benzylidene, 2-benzylidene-amino-carbazole, (2-nitro-benzylidene)-p-bromo-aniline; 2,4-diphenyl quinazoline; 1,2,~-triazine; 1,5-diphenyl-3-methyl pyrazoline 2-(4'-dimethyl-amino phenyl)benzoxazole; 3-amino-carbazole; poly-20 vinylcarbazole-trinitr~luorenone charge transfer complexes; phthalo-cyanines, mixtures thereof, and the like. Generally, positively charged toner compositions are employe~ when the photoreceptor is charged negatively as is the situation withmost organic photoreceptors, while negatively charged toner particles are employed when the photoreceptor is charged positively9 as is the 25 situation with most inorganic photoreceptors such as selenium.
Illustrative examples of insulating toner resin materials that can be utilized include for example polyamides, epoxies, polyurethanes, vinyl resins and polymeric esterification products of a dicarboxylic acid and adiol com-prising a diphenol. Various suitable vinyl resins can be employed in the toners 30 o-f the present system including homopolymers or copolymers of two or more vinyl monomers. Typical of such vinyl monomeric units include: styrene, ~
chlorostyrene vinyl naphthalene, ethylenically unsaturated mon~olefins such as ethylene, propylene, butylene, isobutylene and the lilce; vinyl esters such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, 35 vinyl benzoate, vinyl butyrate and the like; esters ot alphamethylene aliphatic ~3~'7~i~
monocarboxylic acids such asmethyl acrylate, ethyl arylate, n-butylacrylate, isobutyl arylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylte, phenyl acrylate, methylalphachloroacrylate, methyl metharylate, ethyl met~arylate, butyl methacrylate and the like; acrylonitrile, methacrylonitrile, 5 acrylamide, vinyl ethers such as vinyl methyl ether, vinyl isobutyl ether, vinyl ethyl ether, and the like; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone and the like; vinylidene halides such as vinylidene chloride, vinylidene chlorofluoride and the like; and N-vinyl indole,N-vinyl pyrrolidene and the like; and mixtures thereoI.
Generally toner resins containing a relatively high percentage of styrene are preferred since greater image definition and density is usually obtained with their use. The styrene resin employed rnay be a homopolymer of styrene or styrene homologs of copolymers of styrene with other monomeric groups containing a single methylene group attached to a carbon atom by a double bond. Any of the above typic~l monomeric units may be copolymerized with styrene by addition polymerization. Styrene resins may also be formed by the polymerization of mixtures of two or more unsaturated monomeric materials with a styrene monomer. The addition polymerization technique employed emhraces known polymerization techniques such as free radical, anionic and cationic polymerization processes. Any of these vinyl resins may be blended with one or more resins if desired, preferably other vinyl resins whicll insure good triboelectric properties and uniform resistance a~ainst physical degradation. However, non-vinyl type thermoplastic resins may also be employed including resin modified phenolformaldehyde resins, oilmodiIied epo~y resins, polyurethane resins, cellulosic resins, polyether resins and mixtures thereoE.
~Nso esterification products of a dicarboxylic acid and a diol comprising a diphenol may be used as a preferred resin material for the toner composition of the present invention. These materials are illustrated in U.S.
accordingly, the toner partieles exiting from the charging zone 19 contain thereon positive charges 24'. The charging electrode means 16 is self-spaced from the roller means 12 by the toner particles situated therebetween, and the voltage source, 18, Vc, supplies the charge to the electrode 16, which charge inthe embodiment shown is of a positive polarity. The positively charged toner particles continue to migrate on the roller means 12~ until they contact the latent image contained on the imaging member means 10, wherein they are electrostatically attracted to the image, causing development. Unused charged toner particles are returned to the toner supply reservoir 14 on the roller means 12 as shown. The doctor blade 17 provides sufficient pressure to the imaging member means 10 so as to cause said imaging mermber means to be in constant contact with the charged insulating toner particles as shown.
Voltage, 20, VB, also assists in providing for attraction between the charged toner particles and the image contained on the imaging member 10.
An important feature of the present invention resides in the charging electrode means 16, which electrode injects positive charges, or negative charges into the insulating toner particles 24 contained on the roller means 12. The polarity of the charge, and the magnitude of charge injected is controlled by the voltage source Vc 18, thus if a positive polarity is desired on the toner particles, a positive voltage source is applied to the inJecting 5 contact means 16, while if a negative polarity is desired on the insulating toner particles, a negative voltage Vc is applied to the charging electrode means 16.
Charges of the appropriate polarity and magnitude are injected into and accepted by the insulating toner particles as a result of the contact between such particles and the injecting electrode means 16, which is self-spaced from 10 the roller means 1~ by the insulating toner particles situated in the charging zone 19. As indicated herein, generally only one layer of toner particles is contained on the roller means 12, although less or more than one layer of toner particles can be present on rol1er 12, however, if several layers of uncharged toner particles are contained on the roller means 12, difficulties can be 15 encountered in completely charging all the layers of toner particles, since the charge being injected by the electrode 16 cannot usually penetrate more than a few layers of toner particles. The resulting charged insulating toner particles can easily be transferred to plain bond paper subsequent to development as contrasted with conductive toner particles which contain conducting agents 20 therein, and are very difficult to transfer to plain bond paper.
The roller means 12 is comprised of a core which can be hollow or solid and is comprised of numerous known suitable materials including for example, aluminum, steel, iron, polymeric materials, ~md the like~ providing they are of sufficient strength to be operable in the system, with the preferred25 core material being aluminum. (~enerally, this roll has a diameter of from about 1 inch to about 3 inches and preferably has a diameter of from 1 inch to 2inches. This roll can be of a larger or small diameter providing it accom-plishes the objectives of the present invention.
The roller means 12 contains thereon a resistive textured coating 30 layer 13 such as aluminized ~aylar overcoated with carbon black, Krylo~ultra flat black paint, commercially available as Krylon 1602, and various other similar resistive materials. The thiclcness of the coatin@; can vary over a widerange and is dependent on many factors including economical considerations, however, generally the thickness of this coating is from about 0.1 mils to about35 5 mils and preferably is from about 1 mil to about 3 mils. While it is not desired to be limited by theory~ it is believed that the coating assists in c~ rk5 ~a~
increasing the efficiency of charge injection from the charge injecting electrode 16, in that for example, negative charges, which would tend to neutrali~e the positive charges of the charged toner particles contained on the charging roll 12 are prevented from being attracted to the positively charged 5 toner particles. Similarly, when a negative charge is injected into the insulating toner particles, a corresponding positive charge results on the roller means 12, and it is desired to prevent such a charge from migrating to the negatively charged toner particles.
The amount of charge applied to the uncharged insulating toner 10 particles is primarily dependent on the voltage source 18 Vc, which charge generally ranges from about lûO volts to about 500 volts3 and preferably from about 200 volts to about 300 volts when a positive polarity is desired on the insulating uncharged toner particles. When a negative polarity is desired on the uncharged insulating toner particles, the voltage Vc 18 is from about a -10015 volts to about a-500 volts, and preferably erom about a -200 volts to about a -300 volts.
The charge injected into the uncharged toner particles is not onl~J
dependent on the voltage source 18 Vc but on a number of other factors including for e~ample, the number of layers of particles charged, the material 20 utilized as coating 13, and the like. lIowever, generally the uncharged tonerparticles acquire a charge of from about 10 microcoulombs per ~ram to about 35 microcoulombs per gram, and preferably from about 11) microcoulombs per gram to about 20 microcoulombs per gram. Such toner particles are thus of sufficient conductivity so as to be attracted to the image contained on the 25 imaging member means 10, but yet sufficiently insulating in order that they may be easily transferable to plain bond paper.
The voltage source 20, VB, which is primarily employed for background control in the image areas in that it prevents deposition of the charged insulating toner particles in the background areas ranges from about 30 -75 volts to about -200 volts and preferably ranges from about a -75 volts to about a -150 volts.
The injecting eleetrode means 16 can be comprised of various suitable materials providing it is capable Oe accepting charge from the voltage source 18 Vc, and furthera such electrode means 16 should be comprised of a 35 material that will enable the injection of positive or negative charges erom the injecting source means 16 into the uncharged insulating toner particles in 7~i5 accordance with the features of the present invention. C~enerally, the injecting or ~harging electrode can be comprised of metallic substances such as aluminum, steel, iron and the like, with aluminum being preferred. The eharging electrode means 16 is usually not maintained in a fixed position, 5 rather it generally contains thereon a foam backing which is not shown7 so as to allow it to contact the roller means 12, which contact is usually prevented by the layer of insulating uncharged toner particles contained between the charge injecting means 16 and the roller means 12. Thus, the charging electrode means 16 is self-spaced from the roller means 12, such self-spacing 10 being dependent on the number of layers of toner particles contained in the charging zone l9. The length of the charging zone 19 ean vary providing the objectives of the present invention are accomplished, generally however, this length is from about 5 millimeters to about 30 millimeters9 and preferably from about lD millimeters to about 20 millimeters.
The direction of movement of the roller means 12 and the imaging member means 10 can be as shown, that is, in the same direction, or in a dire~tion opposite to each other, that is, roUer 12 can move in the direction opposite to that of the direction of movement of imaging member means 10.
~enerally, roller means 12 is moving at a rate o speed that is faster than the 20 rate of speed OI movement of the irnaging member means 10, thus the speed ratio of the charging roll 12 to the imaging member means 10 varies from about 4 to about 1 and is preferably from about 2 to about 3. Accordingly thus, in this embodiment, the roller 12 is moving at a higher speed (d~) than the speed of the imaging member means 11~.
The pressure blade 17 can be comprised of numerous suitable materials including plastics, nylon, steel, aluminum and the like with the forcebeing exerted by such blade being of sufficient value so as to maintain the imaging member 10 in contact with the charged insulflting toner particles, such force ranging generally from about 0.3 pounds per inch to about 3 pounds per 30 inch and preferably from about 0.5 pounds per inch to about 1 pound per inch.The process and apparatus of the present invention can be utilized in various imaging systems including electrostatic latent imaging systems as shown for example in Figure 2. In Figure 2 there is illustrate~ a xerographic imaging system employing an imaging member 1, which corresponds to the 35 imaging member 10 of Figure 1. In this embodiment of the present invention the imaging member 1 can be comprised of a substrate, overcoated with a 3r7~j _9_ transport layer containing N,~,N',N'-tetraphenyl-[l,lt-biphenyl] ~4'-diamine, or similar diamines dispersed in a polycarbonate, which in turn is overcoated with a generating layer of trigonal selenium. Imaging member 1 moves in the direction of arrow 27 to advance successive portions of the imaging member 5 sequentially through the various processing stations disposed about the path of movement thereof. The imaging member is entrained about a sheet-stripping roller 2~, tensioning means 29, and drive roller 30. Tensioning means 29 includes a roller 31 having Ilanges on opposite sides thereo~ to define a path through which member 1 moves, with roller 31 being mounted on each end of 10 guides attached to springs. Spring 32 is tensioned such that roller 31 presses against the imaging belt member 1. In this manner, member 1 is placed under the desired tension. The level of tension is relatively low permitting member 1 to be easily deformed. With continued reference to Figure 2, drive roller 30 is mounted rotatably and in engagement with member 1. Motor 33 rotates r oller 15 30 to advance member 1 in the direction of arrow 27. Roller 30 is coupled to motor 33 by suitable means such as a belt drive. Sheet-stripping roller 2g is freely rotatable so as to readily permit member 1 to move in the direction of arrow 27 with a minimum of friction.
Initially, a portion of imaging member 1 passes through charging 2~ station H. At charging station H, a eorona generating device, indicated generally by the reference numeral 34, charges the photoconductive surface of imaging member 1 to a relatively high, substantially uniform potential.
The charged portion of the photoconductive surface is then advanced through exposure station I. An original document 35 is positioned 25 face down upon transparent platen 36. Lamps 37 flash light rays onto originaldocument 35, and the light rays reflected from original document 35 are transmitted through lens 38 forming a light image thereof. Lens 3~ fc~cuses the light image onto the charged portion of the photoconductive surface to selectively dissipate the charge thereon. This records an electrostatic latent 30 image on the photoconductive surface which corresponds to the informational areas contained within original document 35.
Thereafter, imaging member 1 advances the electrostatic latent image recorded thereon to station J wherein it is contacted with positively charged insulating toner particles 24', station J including a roller means 12, 35 coating 13, a charging injecting means 16, a toner supply reservoir 1~, pressur bladel7, charging zone 19, and insulating toner particles 24. The details of the ~3~ 5 -ln charging of the toner particles and deposition thereon on the imaging member are illustrated with reference to Figure 1.
Imaging member 1 then advances the toner powder image to transfer station K. At transEer station K, a sheet of support maierial 44 is 5 moved into contact with the ts~ner powder image. The sheet of support material 44 is advanced to transfer station K by a sheet feeing apparatus (not shown)O Preferably, the sheet feeding apparatus includes a feed roll contacting the uppermost sheet of a stack of sheets. The feed roll rotates so as to advance the uppermost sheet from the stack into a chute, which chute directs 10 the advancing sheet of support material into contact with the photoconductivesurface of member 1 in a timed sequence in order that the toner powder image developed thereon contacts the advancing sheet of support material at transfer station K.
Transfer station K incluc!es a corona generating device 46 which 15 sprays ions onto the backside of sheet 44, allowing for the attraction of the torler powder image from the photoconductive surface to sheet 44. After transfer, sheet 44 moves in the direction of arrow 48 onto a conveyor (not shown) which advances sheet 44 to fusing station L.
Fusing station L includes a fuser assembly, indicated generally by 20 the reference numeral S0, which permanently affixes the transferred toner powder image to sheet 44. Preferably, fuser assembly 50 includes a heated fuser roller 52 and a back-up roller 54. Sheet 44 passes between fuser`roller 52 and back-up roller 54 with the toner powder image contacting fuser roller 52. In this mannerl the toner powder image is permanently affixed to sheet 25 44~ After fusing, a chute guides the advancing sheet 44 to a catch tray for subsequent removal from the printing machine.
Invariably, after the sheet of support material is separated from the photoconductive surface of imaging member 1 some residual particles remain adhering thereto. These residual particles are removed from the 30 photoconductive surface at cleaning station M. Cleaning station L includes a rotatably mounted fibrous brush 56 in contact with the photoconducti-le surface. The particles are cleaned from the photoconductive surface by the rotation of brush 56 in contact therewith. Subsequent to cleaning, a discharge lamp (not shown) floods photoconductive surface 12 with light to dissipate any 35 residual electrostatic charge remaining thereon prior to the charging thereof for the next successive imaging cycle.
'7g~
It is believed that the foregoing description is suff icient for purposes of the present invention to illustrate the general operation of an electrophotographic printing machine incorporating the features of the present invention therein.
nlustrative examples of the imaging member 1 or 1~1 includes inorganic and organic photoresponsive materials such as a~orphous selenium, selenium alloys, including alloys of selenium-tellurium, selenium arsenic, selenium antimony, selenium-tellurium-arsenic, cadmium sulfide, zinc oxide, polyvinylcarbazole, layered organic photoreceptors, such as those containing as an injecting contact, carbon dispersed in a polymer, overcoated with a transport layer, which in turn is overcoated with a generating layer, and finally an overcoating of an insulating organic resin, reference U.S. Patent 4,251,612, overcoated layers comprised of a substrate, a charge transport layer,and a charge generating layer, reference U.~. Patent 4,265,990 and the like.
Other organic photoreceptor materials include, ~dimethyl-aminobenzylidene, ben2hydrazide; 2-benzylidene-amino-carbazole, 4-dimethyl-amino-benzylidene, 2-benzylidene-amino-carbazole, (2-nitro-benzylidene)-p-bromo-aniline; 2,4-diphenyl quinazoline; 1,2,~-triazine; 1,5-diphenyl-3-methyl pyrazoline 2-(4'-dimethyl-amino phenyl)benzoxazole; 3-amino-carbazole; poly-20 vinylcarbazole-trinitr~luorenone charge transfer complexes; phthalo-cyanines, mixtures thereof, and the like. Generally, positively charged toner compositions are employe~ when the photoreceptor is charged negatively as is the situation withmost organic photoreceptors, while negatively charged toner particles are employed when the photoreceptor is charged positively9 as is the 25 situation with most inorganic photoreceptors such as selenium.
Illustrative examples of insulating toner resin materials that can be utilized include for example polyamides, epoxies, polyurethanes, vinyl resins and polymeric esterification products of a dicarboxylic acid and adiol com-prising a diphenol. Various suitable vinyl resins can be employed in the toners 30 o-f the present system including homopolymers or copolymers of two or more vinyl monomers. Typical of such vinyl monomeric units include: styrene, ~
chlorostyrene vinyl naphthalene, ethylenically unsaturated mon~olefins such as ethylene, propylene, butylene, isobutylene and the lilce; vinyl esters such as vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, 35 vinyl benzoate, vinyl butyrate and the like; esters ot alphamethylene aliphatic ~3~'7~i~
monocarboxylic acids such asmethyl acrylate, ethyl arylate, n-butylacrylate, isobutyl arylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylte, phenyl acrylate, methylalphachloroacrylate, methyl metharylate, ethyl met~arylate, butyl methacrylate and the like; acrylonitrile, methacrylonitrile, 5 acrylamide, vinyl ethers such as vinyl methyl ether, vinyl isobutyl ether, vinyl ethyl ether, and the like; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone and the like; vinylidene halides such as vinylidene chloride, vinylidene chlorofluoride and the like; and N-vinyl indole,N-vinyl pyrrolidene and the like; and mixtures thereoI.
Generally toner resins containing a relatively high percentage of styrene are preferred since greater image definition and density is usually obtained with their use. The styrene resin employed rnay be a homopolymer of styrene or styrene homologs of copolymers of styrene with other monomeric groups containing a single methylene group attached to a carbon atom by a double bond. Any of the above typic~l monomeric units may be copolymerized with styrene by addition polymerization. Styrene resins may also be formed by the polymerization of mixtures of two or more unsaturated monomeric materials with a styrene monomer. The addition polymerization technique employed emhraces known polymerization techniques such as free radical, anionic and cationic polymerization processes. Any of these vinyl resins may be blended with one or more resins if desired, preferably other vinyl resins whicll insure good triboelectric properties and uniform resistance a~ainst physical degradation. However, non-vinyl type thermoplastic resins may also be employed including resin modified phenolformaldehyde resins, oilmodiIied epo~y resins, polyurethane resins, cellulosic resins, polyether resins and mixtures thereoE.
~Nso esterification products of a dicarboxylic acid and a diol comprising a diphenol may be used as a preferred resin material for the toner composition of the present invention. These materials are illustrated in U.S.
3,655,374, the disclosure of which is totally incorporated herein by reference, the diphenol reactant being of the formula as shown in column 4, beginning at line S of this patent and the dicarboxylic acid being of the formula as shown incolumn 6 of the above patent.
Optimum electrophotographic resins result from styrene butyl-methacrylate copolymers, styrene vinyl toluene copolymers, styrene acrylate copolymers, polyester resins, predominantly styrene or polystyrene based 6~
resins as generally described in U.S. Reissue 24,136 and polystyrene blends as described in U.SO 29788,288.
The toncr resin particles can vary in diameter, but generally range from about 5 microns to about 30 microns, and preferably from about 10 5 microns to about 20 microns. The toner resin is present in an amount so that the total of all ingredients total about lOa percent, thus when 5 percent by weight of an alkyl pyridinium compound is present and 10 percent by weight of pigment such as carbon black is present, about 85 percent by weight of resin material is used.
Various suitable pigments or dyes may be employed as the colorant for the toner particles, such materials being well known, and including for example, carbon black,nigrosine dye, aniline blue, calco oilMude, chrome yellow, ultramarine blue, DuPont oil red, methylene blue chloride, phthalo-cyanine blue and mixtures thereof. The pigment or dye should be present in 15 sufficient quantity to render it highly colored so that it will form a clearly visibleimage on the recording member. For example, where conventional xerographic copies ofdocuments are desired9 the toner may comprise a black pigment such as carbon black or a black dye such flS amaplast black dye available from the National Aniline Products Inc. Preferably the pigment is 20 employed in various amounts from about 3 pereent to about 20 percent by weight based on the to$al weight of toner, however7 if the toner colorant employed is a dye, substantially smaller ~uantities may be used.
Additionally, the toner resin may contain a magnetic material, such as the magnetite Mapico Black, as a substitute for the colorant, or in 25 addition thereto, thereby resulting in a magnetic toner. Generally, the magnetite is present in an amount of from about 40 percent by weight to about 80 percent by weight, and preferably from about 50 percent by weight to about 70 percent by weight.
In another feature of the present invention, the insulating toner 30 particles can contain charge enhancing additives, such as quaternary ammonim compounds, alkyl pyridinium compounds, like cetyl pyridinium chloride9 and the like. The charge enhancing additives, which are present in an amount of from about 0.5 percent by weight to about 10 percent by weight, generally impart a positive charge to the toner resin, and thus are primarily useful only 35 in those situations where the toner particles are being positively charged by the injecting electrode.
Other modifications of the present invention will occur to those skilled in the art upon a reading of the present disclosure. These are intended to be encompassed within the scope of the present invention. Thus also envisioned within the scope of the present invention is a process and apparatus 5 for charging insulating toner particles comprised in operative relationship ofmeans for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting, and themeans for injecting being charged to a predetermined potential. Subsequently the charged toner particles can be deposited on a flexible or rigid imaging 10 member contained in an electrostatographic imaging device, as illustrated herein.
Optimum electrophotographic resins result from styrene butyl-methacrylate copolymers, styrene vinyl toluene copolymers, styrene acrylate copolymers, polyester resins, predominantly styrene or polystyrene based 6~
resins as generally described in U.S. Reissue 24,136 and polystyrene blends as described in U.SO 29788,288.
The toncr resin particles can vary in diameter, but generally range from about 5 microns to about 30 microns, and preferably from about 10 5 microns to about 20 microns. The toner resin is present in an amount so that the total of all ingredients total about lOa percent, thus when 5 percent by weight of an alkyl pyridinium compound is present and 10 percent by weight of pigment such as carbon black is present, about 85 percent by weight of resin material is used.
Various suitable pigments or dyes may be employed as the colorant for the toner particles, such materials being well known, and including for example, carbon black,nigrosine dye, aniline blue, calco oilMude, chrome yellow, ultramarine blue, DuPont oil red, methylene blue chloride, phthalo-cyanine blue and mixtures thereof. The pigment or dye should be present in 15 sufficient quantity to render it highly colored so that it will form a clearly visibleimage on the recording member. For example, where conventional xerographic copies ofdocuments are desired9 the toner may comprise a black pigment such as carbon black or a black dye such flS amaplast black dye available from the National Aniline Products Inc. Preferably the pigment is 20 employed in various amounts from about 3 pereent to about 20 percent by weight based on the to$al weight of toner, however7 if the toner colorant employed is a dye, substantially smaller ~uantities may be used.
Additionally, the toner resin may contain a magnetic material, such as the magnetite Mapico Black, as a substitute for the colorant, or in 25 addition thereto, thereby resulting in a magnetic toner. Generally, the magnetite is present in an amount of from about 40 percent by weight to about 80 percent by weight, and preferably from about 50 percent by weight to about 70 percent by weight.
In another feature of the present invention, the insulating toner 30 particles can contain charge enhancing additives, such as quaternary ammonim compounds, alkyl pyridinium compounds, like cetyl pyridinium chloride9 and the like. The charge enhancing additives, which are present in an amount of from about 0.5 percent by weight to about 10 percent by weight, generally impart a positive charge to the toner resin, and thus are primarily useful only 35 in those situations where the toner particles are being positively charged by the injecting electrode.
Other modifications of the present invention will occur to those skilled in the art upon a reading of the present disclosure. These are intended to be encompassed within the scope of the present invention. Thus also envisioned within the scope of the present invention is a process and apparatus 5 for charging insulating toner particles comprised in operative relationship ofmeans for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting, and themeans for injecting being charged to a predetermined potential. Subsequently the charged toner particles can be deposited on a flexible or rigid imaging 10 member contained in an electrostatographic imaging device, as illustrated herein.
Claims (38)
1. An improved apparatus for charging uncharged insulating toner particles which apparatus comprises in operative relationship a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, a voltage source means for said roller means, wherein charges are injected from said charge injecting means into the uncharged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encompassed by said roller means and said charge injecting means.
2. An improved apparatus in accordance with Claim 1 wherein positive charges are injected into the uncharged insulating toner particles.
3. An improved apparatus in accordance with Claim 1 wherein negative charges are injected into the uncharged toner particles.
4. An improved apparatus in accordance with Claim 1, wherein the roller means is textured and has a diameter of from about 1 inch to about 3 inches, and the coating is contained on said roller means in a thickness of fromabout 0.1 mils to about 5 mils.
5. An improved apparatus in accordance with Claim 1, wherein the charging zone length is from about 5 millimeters to about 30 millimeters, and the distance between the charge injection means and the roller means is from about 0.5 mils to about 2 mils.
6. An improved apparatus in accordance with Claim 1 wherein the voltage source means for said injecting means supplies n charge of from about 100 volts to about 500 volts.
7. An improved apparatus in accordance with Claim 1 wherein the voltage source means for said injecting means supplies a charge of from about -100 volts to about -500 volts.
8. An improved apparatus in accordance with Claim I wherein the uncharged toner particles acquire a charge of from about 10 microcoulombs per gram to about 35 microcoulombs per gram.
9. An improved apparatus in accordance with Claim 1 wherein the roller means is comprised of aluminum, the coating is a Krylon ultra flat black paint, and the injecting means is comprised of aluminum.
10. An improved apparatus in accordance with Claim 1 further including an imaging member means, wherein said charged toner particles are deposited on said imaging member means.
11. An improved apparatus in accordance with Claim 10 wherein the imaging member is comprised of an inorganic or organic material.
12. An improved apparatus in accordance with Claim 11 wherein the imaging member is comprised of a substrate, overcoated with a charge transport layer, which in turn is overcoated with a charge generating layer.
13. An improved electrostatographic imaging apparatus comprising a charging means, an imaging means, a development means, a transfer means, a fusing means, and a fixing means, the improvement residing in the development means which comprises in operative relationship a roller means containing a coating thereon, a toner supply means containing therein uncharged insulating toner particles, a charge injecting means, a voltage source means for said charge injecting means, and a voltage source means for said roller means, wherein charges are injected from said charge injecting means into uncharged insulating toner particles deposited on said roller means, said injection accomplished in a charging zone encompassed by said roller means and said charge injecting means, and wherein the resulting charged insulating toner particles are deposited on an imaging member contained in said imaging apparatus.
14. An improved apparatus in accordance with Claim 13 wherein positive charges, or negative charges are injected into the uncharged insulating toner particles.
15. An improved apparatus in accordance with Claim 13 wherein the voltage source means for said injecting means supplies a charge of from about 100 volts to about 500 volts, or a charge of from about -100 volts to about -500 volts.
16. An improved apparatus in accordance with Claim 13 wherein the roller means is textured, the charging zone length is from about 5 millimeters to about 30 millimeters and the distance between the charge injection means and the roller means is from about 0.5 mils to about 2 mils.
17. An improved apparatus in accordance with Claim 13 wherein the roller means is comprised of aluminum, the coating is a Krylon ultra flat black paint, and the injecting means is comprised of aluminum.
18. An improved apparatus in accordance with Claim 13 wherein the imaging member is comprised of an inorganic or organic material, and the toner particles are comprised of a styrene butylmethacrylate copolymer, and carbon black.
19. An improved apparatus in accordance with Claim 18 wherein the organic material is comprised of a substrate, overcoated with a charge transport layer, which is in turn, overcoated with a charge generating layer.
20. An improved apparatus in accordance with Claim 13 wherein the voltage source means for said roller means supplies a charge of from about -75 volts to about -200 volts.
21. An improved process for charging uncharged insulating toner particles which comprises providing uncharged insulating toner particles on a roller containing a coating thereon, contacting said toner particles with a charge injecting electrode, in a charging zone encompassed by said roller and said injecting electrode, providing a voltage source for said charge injecting electrode, and providing a voltage source for said roller, wherein charges are injected into the uncharged insulating toner particles.
22. An improved process in accordance with Claim 21 wherein the voltage source for said roller supplies a charge of from about 100 volts to about 500 volts, resulting in the injection of positive charges into the uncharged insulating toner particles.
23. An improved process in accordance with Claim 21 wherein the voltage source for said roller supplies a charge of from about -100 volts to about -500 volts, resulting in the injection of negative charges into the uncharged insulating toner particles.
24. An improved process in accordance with Claim 21 wherein the roller is comprised of aluminum, the coating is comprised of a Krylon ultra flat black paint, and the injecting electrode is comprised of aluminum.
25. An improved process in accordance with Claim 21 wherein the charged insulating toner particles are subsequently deposited on an imaging member.
26. An improved process in accordance with Claim 21 wherein the imaging member is an inorganic or an organic material.
27. An improved process in accordance with Claim 26 where the roller is moving at a more rapid rate of speed than the imaging member.
28. An improved process in accordance with Claim 26 where the roller and imaging member are moving in the same direction.
29. An improved process in accordance with Claim 26 where the roller and imaging member are moving in opposite directions.
30. An improved process in accordance with Claim 21 wherein the roller means is textured, the charging zone length is from about 5 millimeters to about 30 millimeters, and the distance between the charge injection means and the roller means is from about 0.5 mils to about 2 mils.
31. An improved process in accordance with Claim 21 wherein the toner particles acquire a charge of from about 10 microcoulombs per gram to about 35 microcoulombs per gram.
32. An improved process in accordance with Claim 26 wherein the organic material is comprised of a substrate, overcoated with a transport layer, which in turn is overcoated with a generating layer.
33. An improved process in accordance with Claim 26 wherein the organic material is comprised of a substrate, overcoated with a charge generating layer, which in turn is overcoated with a charge transport layer.
34. An improved apparatus for charging insulating toner particles comprised in operative relationship of a means for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential.
35. An improved apparatus in accordance with Claim 34 wherein the means for transporting is a roller means, the means for injecting is a charge injecting electrode means, which means are charged to a predeter-mined potential by a voltage source.
36. An improved apparatus in accordance with Claim 34 further including a means for supplying uncharged insulating toner particles to the means for transporting.
37. An improved electrostatographic imaging apparatus comprising a charging means, an imaging means, a development means, a transfer means, a fusing means, and a fixing means, the improvement residing in the development means which comprises in operative relationship a means for transporting insulating toner particles, and a means for injecting charges into the insulating toner particles, the means for transporting and the means for injecting being charged to a predetermined potential, wherein the resulting charged insulating toner particles are deposited on an imaging member contained in said imaging apparatus.
38. An improved process for charging insulating toner particles which comprises providing uncharged insulating toner particles on a trans-porting means, contacting said insulating toner particles with a means for injecting charges into the insulating toner particles, the means for trans-porting and the means for injecting being charged to a predetermined potential, wherein charges are injected into the uncharged insulating toner particles.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US28691681A | 1981-07-27 | 1981-07-27 | |
| US286,916 | 1981-07-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1198765A true CA1198765A (en) | 1985-12-31 |
Family
ID=23100707
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000405757A Expired CA1198765A (en) | 1981-07-27 | 1982-06-22 | Apparatus, process for charging insulating toner particles |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0071465B1 (en) |
| JP (1) | JPS5825644A (en) |
| CA (1) | CA1198765A (en) |
| DE (1) | DE3273352D1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6083972A (en) * | 1983-10-14 | 1985-05-13 | Matsushita Graphic Commun Syst Inc | Electrostatic charger for toner |
| JPS60182955A (en) * | 1984-03-01 | 1985-09-18 | 中村物産株式会社 | Production of solid perfume |
| GB8620895D0 (en) * | 1986-08-29 | 1986-10-08 | Unilever Plc | Cosmetic stick |
| EP0577077B1 (en) * | 1992-06-30 | 1998-09-09 | Sharp Kabushiki Kaisha | Developing device and method |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3166432A (en) * | 1959-05-07 | 1965-01-19 | Xerox Corp | Image development |
| US3908037A (en) * | 1971-09-14 | 1975-09-23 | Xerox Corp | Image developing techniques |
| US4092165A (en) * | 1975-05-05 | 1978-05-30 | Xerox Corporation | Method of making a donor member mold |
| JPS5451846A (en) * | 1977-09-30 | 1979-04-24 | Ricoh Co Ltd | Electrostatic latent image developing device |
| JPS54155043A (en) * | 1978-05-26 | 1979-12-06 | Ricoh Co Ltd | Method of developing electrostatic latent image |
| JPS5560960A (en) * | 1978-10-31 | 1980-05-08 | Agfa Gevaert Nv | Composition for developing electrostatic image and method of development |
| US4410259A (en) * | 1980-03-08 | 1983-10-18 | Mita Industrial Co., Ltd. | Apparatus for developing latent electrostatic image |
-
1982
- 1982-06-22 CA CA000405757A patent/CA1198765A/en not_active Expired
- 1982-07-16 JP JP57124286A patent/JPS5825644A/en active Pending
- 1982-07-27 EP EP19820303973 patent/EP0071465B1/en not_active Expired
- 1982-07-27 DE DE8282303973T patent/DE3273352D1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0071465B1 (en) | 1986-09-17 |
| DE3273352D1 (en) | 1986-10-23 |
| EP0071465A2 (en) | 1983-02-09 |
| EP0071465A3 (en) | 1983-08-03 |
| JPS5825644A (en) | 1983-02-15 |
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