US3862420A - System to prevent the formation of particulate material in corona units - Google Patents
System to prevent the formation of particulate material in corona units Download PDFInfo
- Publication number
- US3862420A US3862420A US411987A US41198773A US3862420A US 3862420 A US3862420 A US 3862420A US 411987 A US411987 A US 411987A US 41198773 A US41198773 A US 41198773A US 3862420 A US3862420 A US 3862420A
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- United States
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- air
- corona
- active material
- chemically active
- flow
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- Expired - Lifetime
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- 239000011236 particulate material Substances 0.000 title claims abstract description 23
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 11
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 68
- 239000011149 active material Substances 0.000 claims abstract description 40
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 34
- 206010011906 Death Diseases 0.000 claims abstract description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 26
- 238000001914 filtration Methods 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 14
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 13
- 239000012876 carrier material Substances 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 10
- 239000000741 silica gel Substances 0.000 claims description 10
- 229910002027 silica gel Inorganic materials 0.000 claims description 10
- 230000008859 change Effects 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 6
- 239000013078 crystal Substances 0.000 claims description 6
- 239000002245 particle Substances 0.000 abstract description 12
- 239000000428 dust Substances 0.000 abstract description 6
- 238000011109 contamination Methods 0.000 abstract description 4
- 239000003570 air Substances 0.000 description 55
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 9
- 230000008021 deposition Effects 0.000 description 8
- 238000012546 transfer Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 125000006850 spacer group Chemical group 0.000 description 3
- 239000004480 active ingredient Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000007786 electrostatic charging Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 239000004254 Ammonium phosphate Substances 0.000 description 1
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 229910000148 ammonium phosphate Inorganic materials 0.000 description 1
- 235000019289 ammonium phosphates Nutrition 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 230000002844 continuous effect Effects 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000011496 polyurethane foam Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
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
- G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
- G03G15/0258—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices provided with means for the maintenance of the charging apparatus, e.g. cleaning devices, ozone removing devices G03G15/0225, G03G15/0291 takes precedence
-
- 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
- G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
- G03G15/0291—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices corona discharge devices, e.g. wires, pointed electrodes, means for cleaning the corona discharge device
Definitions
- the ammonia filter contains a chemically active material to react with the ammonia in the [56] I Refefences Cited 3i; zirixdmitzggrgtttgsris provided to sense end-of-life of UNITED STATES PATENTS 3,306,011 2/1967 Ovorkin 55/275 15 Claims, 5 Drawing Figures I r CHARGE AMMONIA CORONA FILTER OZONE FILTER PARTICLE G FILTER. 7
- Corona discharge devices have been widely used in prior art systems as ion generators for electrostatic charging. These prior art corona discharge devices have had, after a period of usage, a particulate material collect on the insulating surfaces of the corona unit as well as the non-corona electrodes such as screens or a conductive backing electrode. The growth of the particulate material on the screens or backing electrodes increases the arc probability and also changes the charge efficiency of the corona device. At high humidities the wet particulate material further increases the chance of electrical shorts and corrosion of corona I components. The particulate material may also contaminate nearby components such as the photoconductor in an electrophotographic imaging system for example.
- the'corona units since it was believed that the'corona units generate from the normal gases in air, ozone, oxides of nitrogen, and ammonia which combine to produce the particulate material. In systems utilizing corona devices in which the components of the system are required to have maintenance free operation for a long period of time, the prior art solution isno longer suitable. In investigating alternatives to the prior art practices, it was discovered that the internally generated particulate material comprises but a small percentage of the total particulate material. It was discovered that oxides of nitrogen were generated in relatively large amounts by both positive and negative corona discharges and that these oxides react readily with ammonia to form ammonium nitrate particulate which appears to be the particulate formed with the greatest concentration.
- the quantity of the ammonium nitrate particulate formed could not be attributed to the internal generation of ammonia within the corona since the concentration was much too lowfor the ammonium nitrate particulates. It was discovered that the formation of particulate materials is greatly affected by the level of ammonia in the ambient air which may be introduced to the corona discharge device.
- apparatus for supplying a flow of air to a corona discharge device over a path which includes filtering means comprising a chemically active material to react with certain components in the flow of air to prevent the formation of particulate material in the corona device and associated apparatus.
- FIG. 1 is a schematic view of'an electrophotographic apparatus embodying the present invention
- FIG. 2 is a block diagram of the air, filtering system embodying the present invention
- FIG. 3 is a view partially in section of the ammonia filter
- FIG. 4 is a cross-sectional viewof the charge corona showing the air path through the corona unit
- FIG. 5 is a partial cross-section view of the ammonia filter showing the addition of a use level sensing device.
- This invention is applicable in general to corona discharge devices utilized as ion generators for electrostatic charging.
- the embodiment of the invention described relates to an electrophotographic apparatus since the particulate material deposition problem may be particularly severe in this environment.
- a rotatable drum 1 carries around its periphery of an electrophotographic photoconductive member upon which is directed an image which it is desired to be produced on continuous form web 6, The surface of the photoconductor is uniformly charged to a predetermined polarity by corona discharge device 2.
- the charged surface is exposed to a light image at the forms flash station 3 and/or exposure station 4 to produce a latent electrostatic image;
- the latent electrostatic image is developed by a suitable development unit 5 at which a toner carrier mixture is cascaded across the electrostatic image on the'surface of the photoconductor as is known in the art.
- the toner has a charge such that it is attracted to the drum surface to render the image visible.
- the toned image is transferred to contin-- uous form sheet 6 with the aid of transfer corona unit 7.
- the transfer corona unit sprays ions on the backside of sheet 6 of a polarity opposite that of the toner, thereby attracting the toner image from drum 1 to sheet 6.
- a fusing station 8 which serves to fuse and permanently fix the toner to the paper. Since transfer of all the image toner is not usually accomplished, residual toner usually remains on the drum surface after a transfer operation.
- the photoconductor is exposed successively to an erase lamp 9, a pre-clean corona l0 and a rotating cleaning brush 11.
- the erase lamp discharges the photoconductor and the pre-clean corona produces a-charge so that the residual image toner is attracted electrostatically to the cleaning brush which sweeps the toner from the photoconductor surface. This operation completes the cycling of the drum for producing the desired image.
- Control means 14 is provided to supply electrical control signals to coordinate the operation of all components of the system. In this manner the position of the image on the drum can be coordinated so that the proper action takes place at the stations around the drum at the proper time. In addition, control means 14 may also provide temporary storage for image data supplied to exposure station 4 if desired.
- the charge corona 2 has associated therewith a filtering means 15 and an air flow means 16 which produces a flow of air through the charge corona unit to reduce or eliminate three types of contamination within the corona unit, namely, corrosion, deposition of particulate materials and dust.
- filtering means 15 comprises a particle filter which receives the air from air flow means 16.
- air flow means 16 comprises a suitable blower.
- Particle filter 20 is a device suitable for removing particles above about 1 micron in size from the flow of air and this filter is operable to greatly reduce the dust contamination in the charge corona.
- Air from particle filter 20 is passed to ammonia filter means 22 where any ammonia present in the air reacts chemically to produce virtually ammonia-free and dust-free air for introduction into the charge corona.
- the air is channeled through the charge corona so that the air flow tends to keep the corona wires clean.
- the flow path within the charge corona is set up so that any remaining toner particles near the photoconductor surface are kept away from the wires by the air flow and swept out of the corona unit along with the ozone that is normally generated within the corona unit.
- This air is directed through a suitable ozone filter 24 to remove the ozone generated within the charge corona unit and the air from the ozone filter can either be exhausted from the system or returned to the system for recycling.
- FIG. 3 A specific embodiment for ammonia filter 22 is shown in FIG. 3.
- Housing 34 is made from or coated with a material that is chemically inert relative to the chemically active material, and is designed to facilitate the flow of air through the filter.
- the chemically active material is held in position by a retaining member 28 and a spacer member on either side of the chemically active material.
- Retaining member 28 comprises any suitable member which will physically constrain the chemically active material and permit the free flow of air through the member.
- a screen member with greater than 50 percent open area is suitable for the retainer member.
- Spacer member 30 comprises any suitable chemically inert material such as an open cell foam for example. In a particular embodiment a polyurethane foam having to 80 pores per inch was found to be suitable.
- the retaininng member 28 and spacer member 30 perform the dual functions of holding the chemically active material
- the chemically active material comprises a suitable carrier material and an active ingredient such as an acid which reacts with certain components in the air.
- the carrier material should either be porous or have a high surface area and be compatible with an indicator if used.
- the active ingredient should react readily with the components to be removed from the air, have a low vapor pressure, and be chemically inert relative to the carrier material.
- One suitable chemically active material is a carrier material comprising activated charcoal treated with a vapor pressure, a substantial amount of the sulfuric. acid is adsorbed in the pores of filter material.
- a typical filter treated in this manner contains about 5 percent of sulfuric acid by weight.
- An alternate chemically active material is a carrier material comprising silica gel treated with a solution of phosphoric acid. The silica gel is soaked in phosphoric acid. The resultant material is vacuum dried and a substantial amount of phosphoric acid is adsorbed in the pores of the carrier material.
- a typical filter treated in this manner may contain about 15 percent of phosphoric acid by weight.
- This construction of the ammonia filter provides a large surface area for reacting with the ammonia present in the air to be supplied to the charge corona.
- the charge corona comprises a plurality of corona wires 40 spaced apart a predetermined distance and a plurality of screen wires 42 that are spaced apart a considerably shorter distance than the spacing between corona wires.
- a suitable power source 44 is provided to supply a corona generatingpotential such as several kilovolts for example to corona wires 40 and a lower potential to screen wires 42.
- the voltages are referenced to the photoconductor backing electrode which is normally at ground potential.
- An inner housing 48 is provided which has end members extending close to thesurface of the photoconductor to produce a controlled flow of air through the corona device.
- housing 48 which extends away from the photoconductor is divided by a perforated plate member 50 so that the part of the housing behind the plate member provides a manifold for the air directed to'the charge coronayThe air is directed from outlet port 36 to inlet 52 by suitable'ducts and is forced through the holes in plate member 50 across the corona wires and screen wires toward the photoconductor surface.
- An outer housing 56 is provided on the charge corona and an air outlet 54 is provided so that a pressure differential can be established between the input air and the output air to cause a controlled flow of air substantially according to the arrows shown in the drawing.
- the re sult of the illustrated air flow is that all contaminating dust is carried away from the corona and screen wires and out through outlet 54.
- the ozone that is generated within the charge corona is also carried away through this outlet.
- ammonia level in the air introduced to the charge corona is less than one part per billion and this is effective in eliminating the particulate deposition problem so that the charge corona can be operated for long periods ofmaintenance free operation.
- ammonia level in air varies considerably. In unpolluted air the average is about 6 parts per billion; however, the air near chemical processes which produce or use ammonia have much higher ammonia levels, perhaps as high as 5000 parts per billion.
- a filter end-oflife indicator is desirable.
- An end-of-life indicator is provided in the embodiment shown in FIG. 5. The indicator operates on the basis of the change in the pH of the system as the chemically active material goes, for example, from phosphoric acid to ammonium phosphate.
- the chemically active material is made from a suitable carrier material to which a suitable color indicator can be added to show when the pH of the system gets to the critical value.
- a window 58 is provided in a recess within housing 34 which is transparent to the spectrum of the light from light source 60.
- Light source 60 is imaged on the window 58 by a suitable lens 62 and the light transmitted back through window 58 is collected by lens 64 and passed through a suitable color filter 66 to a photocell 68.
- the carrier material is silica gel which has been treated as described above with phosphoric acid.
- a suitable color indicator material such as crystal violet is also introduced into the chemically active material 32'.
- the material is normally light yellow; however, at the critical pl-l designated to indicate end-of-life of the filter, the color indicator material changes to dark violet so that the amount of light reaching photocell 68 changes and a suitable electrical signal can be generated by monitoring the photocell cally active material so that some amount of operating time would beleft after the signal is generated so that the filter could be changed at a convenient time in the operation of the machine.
- the color change starts at the input side of the filter and progresses toward the output side.
- the vertical position of window 58 along the filter can be chosen at any particular position so that the indication corresponds to the desired usage level.
- An elongated transparent window may be mounted vertically in housing 34' to provide a visual indication of the usage level of the filter. It is obvious that a light transmission system can be utilized for the filter end-of-life indicator wherein a color change or a density change can be sensed.
- Apparatus for producing charge on a surface comprising; comprising:
- filtering means positioned in said predetetermined path between said means for producing a flow of air and said corona means so that said air flows through said filtering means, said filtering means comprising a carrier material treated with an acid to form a chemically active material to produce a chemical reaction with certain of said undesired gaseous components in said flow of air to prevent the formation of particulate material in said corona means over an extended period of operation.
- one of said undesired gaseous components in said flow of air is ammonia and wherein said chemically active material produces a chemical reaction with the ammonia in said flow of air.
- said chemically active material comprises activated charcoal which is treated with sulfuric acid.
- said chemically active material comprises silica gel which is treated with phosphoric acid.
- An electrophotographic apparatus for producing an image on a recording surface comprising:
- corona means for producing a charge on a recording surface; means for producing a flow of air having undesired gaseous components therein to and through said coronameans over a predetermined .path; filtering means positioned in said predetermined path between said means for producing a flow of air and said corona means so that said air flows through said filtering means, said filtering means comprising a carrier material treated with an acid to form a chemically active material to produce a chemical reaction with certain of said undesired gaseous components in said flow of air to prevent the formation of particulate material in said electrophotographic apparatus over an extended period of operation.
- said chemically active material comprises activated charcoal which is treated with sulfuric acid.
- one of said undesired gaseous components in said flow of air is ammonia and wherein said chemically activematerial produces a chemical reaction with the ammonia in said flow of air.
- sensing means comprises means for sensing a color change when said filtering means reaches end-of-life.
- sensing means comprises means to sense when said chemically active material reaches a predetermined concentration.
- said means to sense when said chemically active material reaches a predetermined concentration comprises an indicator material within said filtering meanswhich changes color at said predetermined concentration and means to sense the color change.
- said chemically active material comprises silica gel which is soaked in phosphoric acid and then vacuum dried and wherein said indicator material com let.
Abstract
Apparatus is disclosed for supplying air to a corona discharge device to eliminate contamination within the corona unit and associated apparatus. Before introduction of the air into the corona device, the air is first passed through a particle filter to eliminate dust particles and then through an ammonia filter to prevent the formation of particulate material within the corona device. The ammonia filter contains a chemically active material to react with the ammonia in the air and apparatus is provided to sense end-of-life of the ammonia filter.
Description
United StateS'Patent [1 1 [111 3,862,420
Banks et al. 7 Jan. 21 1975 [54] SYSTEM TO PREVENT THE FORMATION 3,471,695 I 10/1969 Hudson 250/324 OF PARTICULATE MATERIAL IN CORONA UNITS Prir nary Examiner-James W. Lawrence [75] Inventors: Willard K. Banks, Santa Clara; Assistant Examinerc- Church Robert J. Cappell, Mountain View, Attorney, Agent, or FirmOtto Schmid, Jr. both of Calif.
[73] Assignee: International Business Machines [57] ABSTRACT Corporation, Armonk, N.Y. Apparatus is disclosed for supplying air to a corona [22] Flled' N0v'11973 discharge device to eliminate contamination within 21] Appl. No.: 411,987 the corona unit and associated apparatus. Before introduction of the air into the corona device, the air is first passed through a particle filter to eliminate dust EZ Z S particles and then through an ammonia filter to pre- [58] Fie'ld 4 vent the formation of particulate material within the 317/262 A, 55/274 275 corona device. The ammonia filter contains a chemically active material to react with the ammonia in the [56] I Refefences Cited 3i; zirixdmitzggrgtttgsris provided to sense end-of-life of UNITED STATES PATENTS 3,306,011 2/1967 Ovorkin 55/275 15 Claims, 5 Drawing Figures I r CHARGE AMMONIA CORONA FILTER OZONE FILTER PARTICLE G FILTER. 7
Patented Jan. 21 1975 3,862,420
2 Sheets-sheaf l CHARGE AMMONIA CORONA FILTER OZONE FILTER PARTICLE 0. FILTER v SYSTEM TO PREVENT THE FORMATION OF PARTICULATE MATERIAL IN CORONA UNITS BACKGROUND OF THE INVENTION This invention relates to corona discharge devices and more particularly to a method and apparatus for eliminating certain particulate deposition within corona discharge devices.
Corona discharge devices have been widely used in prior art systems as ion generators for electrostatic charging. These prior art corona discharge devices have had, after a period of usage, a particulate material collect on the insulating surfaces of the corona unit as well as the non-corona electrodes such as screens or a conductive backing electrode. The growth of the particulate material on the screens or backing electrodes increases the arc probability and also changes the charge efficiency of the corona device. At high humidities the wet particulate material further increases the chance of electrical shorts and corrosion of corona I components. The particulate material may also contaminate nearby components such as the photoconductor in an electrophotographic imaging system for example. The problem of particulate material deposition within corona discharge devices has been solved in prior art systems by periodic cleaning of the corona devices which may beaccompanied by periodic restringing of the corona wires. The mechanism which causes particulate deposition within the corona discharge device is not completely understood, and the deposition varies depending upon whether a positive or negative corona discharge is produced. However, one reason for the prior art practice was because of the belief that all components of the particulate material are totally generated in the normal operation of the corona devices,
since it was believed that the'corona units generate from the normal gases in air, ozone, oxides of nitrogen, and ammonia which combine to produce the particulate material. In systems utilizing corona devices in which the components of the system are required to have maintenance free operation for a long period of time, the prior art solution isno longer suitable. In investigating alternatives to the prior art practices, it was discovered that the internally generated particulate material comprises but a small percentage of the total particulate material. It was discovered that oxides of nitrogen were generated in relatively large amounts by both positive and negative corona discharges and that these oxides react readily with ammonia to form ammonium nitrate particulate which appears to be the particulate formed with the greatest concentration. However, the quantity of the ammonium nitrate particulate formed could not be attributed to the internal generation of ammonia within the corona since the concentration was much too lowfor the ammonium nitrate particulates. It was discovered that the formation of particulate materials is greatly affected by the level of ammonia in the ambient air which may be introduced to the corona discharge device.
SUMMARY OF THE INVENTION It is therefore the principle object of this invention to produce a corona discharge device which is free of the deposition of particulate material and thus capable of producing maintenance free operation for a long period of time.
Briefly, accordingto the invention, apparatus is provided for supplying a flow of air to a corona discharge device over a path which includes filtering means comprising a chemically active material to react with certain components in the flow of air to prevent the formation of particulate material in the corona device and associated apparatus.
DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of'an electrophotographic apparatus embodying the present invention;
FIG. 2'is a block diagram of the air, filtering system embodying the present invention;
FIG. 3 is a view partially in section of the ammonia filter;
FIG. 4 is a cross-sectional viewof the charge corona showing the air path through the corona unit;
FIG. 5 is a partial cross-section view of the ammonia filter showing the addition of a use level sensing device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention is applicable in general to corona discharge devices utilized as ion generators for electrostatic charging. However, the embodiment of the invention described relates to an electrophotographic apparatus since the particulate material deposition problem may be particularly severe in this environment. In this electrophotographic apparatus shown in FIG. 1, a rotatable drum 1 carries around its periphery of an electrophotographic photoconductive member upon which is directed an image which it is desired to be produced on continuous form web 6, The surface of the photoconductor is uniformly charged to a predetermined polarity by corona discharge device 2. The charged surface is exposed to a light image at the forms flash station 3 and/or exposure station 4 to produce a latent electrostatic image; The latent electrostatic image is developed by a suitable development unit 5 at which a toner carrier mixture is cascaded across the electrostatic image on the'surface of the photoconductor as is known in the art. The toner has a charge such that it is attracted to the drum surface to render the image visible. The toned image is transferred to contin-- uous form sheet 6 with the aid of transfer corona unit 7. The transfer corona unit sprays ions on the backside of sheet 6 of a polarity opposite that of the toner, thereby attracting the toner image from drum 1 to sheet 6.'After the corona transfer the paper 6 is separated from the drum and fed past a fusing station 8 which serves to fuse and permanently fix the toner to the paper. Since transfer of all the image toner is not usually accomplished, residual toner usually remains on the drum surface after a transfer operation. At the cleaning station the photoconductor is exposed successively to an erase lamp 9, a pre-clean corona l0 and a rotating cleaning brush 11. The erase lamp discharges the photoconductor and the pre-clean corona produces a-charge so that the residual image toner is attracted electrostatically to the cleaning brush which sweeps the toner from the photoconductor surface. This operation completes the cycling of the drum for producing the desired image.
Control means 14 is provided to supply electrical control signals to coordinate the operation of all components of the system. In this manner the position of the image on the drum can be coordinated so that the proper action takes place at the stations around the drum at the proper time. In addition, control means 14 may also provide temporary storage for image data supplied to exposure station 4 if desired.
According to the present invention, the charge corona 2 has associated therewith a filtering means 15 and an air flow means 16 which produces a flow of air through the charge corona unit to reduce or eliminate three types of contamination within the corona unit, namely, corrosion, deposition of particulate materials and dust. In the embodiment shown, filtering means 15 comprises a particle filter which receives the air from air flow means 16. In the embodiment shown, air flow means 16 comprises a suitable blower. Particle filter 20 is a device suitable for removing particles above about 1 micron in size from the flow of air and this filter is operable to greatly reduce the dust contamination in the charge corona. Air from particle filter 20 is passed to ammonia filter means 22 where any ammonia present in the air reacts chemically to produce virtually ammonia-free and dust-free air for introduction into the charge corona. The air is channeled through the charge corona so that the air flow tends to keep the corona wires clean. In addition, the flow path within the charge corona is set up so that any remaining toner particles near the photoconductor surface are kept away from the wires by the air flow and swept out of the corona unit along with the ozone that is normally generated within the corona unit. This air is directed through a suitable ozone filter 24 to remove the ozone generated within the charge corona unit and the air from the ozone filter can either be exhausted from the system or returned to the system for recycling.
A specific embodiment for ammonia filter 22 is shown in FIG. 3. The air from particle filter 20 enters through port 26, goes through a quantity of chemically active material 32 which is provided in housing 34 and continues to exit port 36. Housing 34 is made from or coated with a material that is chemically inert relative to the chemically active material, and is designed to facilitate the flow of air through the filter. The chemically active material is held in position by a retaining member 28 and a spacer member on either side of the chemically active material. Retaining member 28 comprises any suitable member which will physically constrain the chemically active material and permit the free flow of air through the member. A screen member with greater than 50 percent open area is suitable for the retainer member. Spacer member 30 comprises any suitable chemically inert material such as an open cell foam for example. In a particular embodiment a polyurethane foam having to 80 pores per inch was found to be suitable. The retaininng member 28 and spacer member 30 perform the dual functions of holding the chemically active material in place and uniformly distributing the air flow across the filter.
The chemically active material comprises a suitable carrier material and an active ingredient such as an acid which reacts with certain components in the air. The carrier material should either be porous or have a high surface area and be compatible with an indicator if used. The active ingredient should react readily with the components to be removed from the air, have a low vapor pressure, and be chemically inert relative to the carrier material.
One suitable chemically active material is a carrier material comprising activated charcoal treated with a vapor pressure, a substantial amount of the sulfuric. acid is adsorbed in the pores of filter material. A typical filter treated in this manner contains about 5 percent of sulfuric acid by weight. An alternate chemically active material is a carrier material comprising silica gel treated with a solution of phosphoric acid. The silica gel is soaked in phosphoric acid. The resultant material is vacuum dried and a substantial amount of phosphoric acid is adsorbed in the pores of the carrier material. A typical filter treated in this manner may contain about 15 percent of phosphoric acid by weight. This construction of the ammonia filter provides a large surface area for reacting with the ammonia present in the air to be supplied to the charge corona.
A specific embodiment of the charge corona is shown in FIG. 4. The charge corona comprises a plurality of corona wires 40 spaced apart a predetermined distance and a plurality of screen wires 42 that are spaced apart a considerably shorter distance than the spacing between corona wires. A suitable power source 44 is provided to supply a corona generatingpotential such as several kilovolts for example to corona wires 40 and a lower potential to screen wires 42. The voltages are referenced to the photoconductor backing electrode which is normally at ground potential. An inner housing 48 is provided which has end members extending close to thesurface of the photoconductor to produce a controlled flow of air through the corona device. The portion of housing 48 which extends away from the photoconductor is divided by a perforated plate member 50 so that the part of the housing behind the plate member provides a manifold for the air directed to'the charge coronayThe air is directed from outlet port 36 to inlet 52 by suitable'ducts and is forced through the holes in plate member 50 across the corona wires and screen wires toward the photoconductor surface. An outer housing 56 is provided on the charge corona and an air outlet 54 is provided so that a pressure differential can be established between the input air and the output air to cause a controlled flow of air substantially according to the arrows shown in the drawing. The re sult of the illustrated air flow is that all contaminating dust is carried away from the corona and screen wires and out through outlet 54. In addition, the ozone that is generated within the charge corona is also carried away through this outlet.
Some additionalair is pulled into the charge corona around the gap between outer housing 56 and the photoconductor surface to insure that the flow of air along with the dust and ozone contaminants are removed from the charge coronarather than being distributed to other parts of the machine due to escape from housing 56.
With the above described apparatus the ammonia level in the air introduced to the charge corona is less than one part per billion and this is effective in eliminating the particulate deposition problem so that the charge corona can be operated for long periods ofmaintenance free operation.
The ammonia level in air varies considerably. In unpolluted air the average is about 6 parts per billion; however, the air near chemical processes which produce or use ammonia have much higher ammonia levels, perhaps as high as 5000 parts per billion. The
amount of the chemically active material in the filter determines the ammonia capacity of the filter. Since the ammonia level in air is variable, the life of the filter is also variable. In a system in which long intervals of maintenance-free operation are desired, a filter end-oflife indicator is desirable. An end-of-life indicator is provided in the embodiment shown in FIG. 5. The indicator operates on the basis of the change in the pH of the system as the chemically active material goes, for example, from phosphoric acid to ammonium phosphate. The chemically active material is made from a suitable carrier material to which a suitable color indicator can be added to show when the pH of the system gets to the critical value. In the embodiment shown, a window 58 is provided in a recess within housing 34 which is transparent to the spectrum of the light from light source 60. Light source 60 is imaged on the window 58 by a suitable lens 62 and the light transmitted back through window 58 is collected by lens 64 and passed through a suitable color filter 66 to a photocell 68. As a specific example, the carrier material is silica gel which has been treated as described above with phosphoric acid. A suitable color indicator material such as crystal violet is also introduced into the chemically active material 32'. The material is normally light yellow; however, at the critical pl-l designated to indicate end-of-life of the filter, the color indicator material changes to dark violet so that the amount of light reaching photocell 68 changes and a suitable electrical signal can be generated by monitoring the photocell cally active material so that some amount of operating time would beleft after the signal is generated so that the filter could be changed at a convenient time in the operation of the machine.
The color change starts at the input side of the filter and progresses toward the output side. The vertical position of window 58 along the filter can be chosen at any particular position so that the indication corresponds to the desired usage level. An elongated transparent window may be mounted vertically in housing 34' to provide a visual indication of the usage level of the filter. It is obvious that a light transmission system can be utilized for the filter end-of-life indicator wherein a color change or a density change can be sensed.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in the form and details may be made therein without departing from the spirit and scope of the invention.
What is claimed is:
1. Apparatus for producing charge on a surface comprising; comprising:
corona means for producing a charge on asurface;
means for producing a flow of air having undesired gaseous components therein to and through said corona means over a predetermined path; filtering means positioned in said predetetermined path between said means for producing a flow of air and said corona means so that said air flows through said filtering means, said filtering means comprising a carrier material treated with an acid to form a chemically active material to produce a chemical reaction with certain of said undesired gaseous components in said flow of air to prevent the formation of particulate material in said corona means over an extended period of operation.
2. The apparatus according to claim 1 wherein one of said undesired gaseous components in said flow of air is ammonia and wherein said chemically active material produces a chemical reaction with the ammonia in said flow of air.
3. The apparatus according to claim 1 wherein said chemically active material comprises activated charcoal which is treated with sulfuric acid.
4. The apparatus according to claim 1 wherein said chemically active material comprises silica gel which is treated with phosphoric acid. v
5. The apparatus according to claim 1 wherein said chemically active material comprises silica gel which is treated with phosphoric acid.
6. An electrophotographic apparatus for producing an image on a recording surface comprising:
corona means for producing a charge on a recording surface; means for producing a flow of air having undesired gaseous components therein to and through said coronameans over a predetermined .path; filtering means positioned in said predetermined path between said means for producing a flow of air and said corona means so that said air flows through said filtering means, said filtering means comprising a carrier material treated with an acid to form a chemically active material to produce a chemical reaction with certain of said undesired gaseous components in said flow of air to prevent the formation of particulate material in said electrophotographic apparatus over an extended period of operation. 7. The apparatus according to claim 6 wherein said chemically active material comprises activated charcoal which is treated with sulfuric acid.
8. The apparatus according to claim 6 wherein one of said undesired gaseous components in said flow of air is ammonia and wherein said chemically activematerial produces a chemical reaction with the ammonia in said flow of air.
9. The apparatus according to claim 6. additionally comprising means to sense when said filtering means reaches end-of-life.
10. The apparatus according to claim 9 wherein said sensing means comprises means for sensing a color change when said filtering means reaches end-of-life.
11. The apparatus according to claim 9 wherein said sensing means comprises means to sense when said chemically active material reaches a predetermined concentration.
12. The apparatus according to claim 11 wherein said means to sense when said chemically active material reaches a predetermined concentration comprises an indicator material within said filtering meanswhich changes color at said predetermined concentration and means to sense the color change.
13. The apparatus according to claim 12 wherein said indicator material comprises crystal violet.
14. The apparatus according to claim 12 wherein said chemically active material comprises silica gel which is soaked in phosphoric acid and then vacuum dried and wherein said indicator material com let.
prises crystal vio-
Claims (15)
1. Apparatus for producing charge on a surface comprising; comprising: corona means for producing a charge on a surface; means for producing a flow of air having undesired gaseous components therein to and through said corona means over a predetermined path; filtering means positioned in said predetetermined path between said means for producing a flow of air and said corona means so that said air flows through said filtering means, said filtering means comprising a carrier material treated with an acid to form a chemically active material to produce a chemical reaction with certain of said undesired gaseous components in said flow of air to prevent the formation of particulate material in said corona means over an extended period of operation.
2. The apparatus according to claim 1 wherein one of said undesired gaseous components in said flow of air is ammonia and wherein said chemically active material produces a chemical reaction with the ammonia in said flow of air.
3. The apparatus according to claim 1 wherein said chemically active material comprises activated charcoal which is treated with sulfuric acid.
4. The apparatus according to claim 1 wherein said chemically active material comprises silica gel which is treated with phosphoric acid.
5. The apparatus according to claim 1 wherein said chemically active material comprises silica gel which is treated with phosphoric acid.
6. An electrophotographic apparatus for producing an image on a recording surface comprising: corona means for producing a charge on a recording surface; means for producing a flow of air having undesired gaseous components therein to and through said corona means over a predetermined path; filtering means positioned in said predetermined path between said means for producing a flow of air and said corona means so that said air flows through said filtering means, said filtering means comprising a carrier material treated with an acid to form a chemically active material to produce a chemical reaction with certain of said undesired gaseous components in said flow of air to prevent the formation of particulate material in said electrophotographic apparatus over an extended period of operation.
7. The apparatus according to claim 6 wherein said chemically active material comprises activated charcoal which is treated with sulfuric acid.
8. The apparatus according to claim 6 wherein one of said undesired gaseous components in said flow of air is ammonia and wherein said chemically active material produces a chemical reaction with the ammonia in said flow of air.
9. The apparatus according to claim 6 additionally comprising means to sense when said filtering means reaches end-of-life.
10. The apparatus according to claim 9 wherein said sensing means comprises means for sensing a color change when said filtering means reaches end-of-life.
11. The apparatus according to claim 9 wherein said sensing means comprises means to sense when said chemically active material reaches a predetermined concentration.
12. The apparatus according to claim 11 wherein said means to sense when said chemically active material reaches a predetermined concentration comprises an indicator material within said filtering means which changes color at said predetermined concentration and means to sense the color change.
13. The apparatus according to claim 12 wherein said indicator material comprises crystal violet.
14. The apparatus according to claim 12 wherein said chemically active material comprises silica gel which is treated with phosphoric acid and wherein said indicator material comprises crystal violet.
15. The apparatus according to claim 12 wherein said chemically active material comprises silica gel which is soaked in phosphoric acid and then vacuum dried and wherein said indicator material comprises crystal violet.
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US411987A US3862420A (en) | 1973-11-01 | 1973-11-01 | System to prevent the formation of particulate material in corona units |
FR7431441A FR2250216B1 (en) | 1973-11-01 | 1974-09-11 | |
IT27467/74A IT1027571B (en) | 1973-11-01 | 1974-09-19 | SYSTEM TO PREVENT THE FORMATION OF DEPOSITS IN COMBINATION WITH THE CORONA EFFECT |
JP49113981A JPS5828581B2 (en) | 1973-11-01 | 1974-10-04 | corona tie den sochi |
GB4411774A GB1444669A (en) | 1973-11-01 | 1974-10-11 | Corona discharge devices |
DE19742448761 DE2448761A1 (en) | 1973-11-01 | 1974-10-12 | ARRANGEMENT TO AVOID THE FORMING OF CORPUSCULAR MATERIAL IN CORONA Discharge DEVICES |
CA74212264A CA1049089A (en) | 1973-11-01 | 1974-10-25 | Particulate material in corona units |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US411987A US3862420A (en) | 1973-11-01 | 1973-11-01 | System to prevent the formation of particulate material in corona units |
Publications (1)
Publication Number | Publication Date |
---|---|
US3862420A true US3862420A (en) | 1975-01-21 |
Family
ID=23631093
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US411987A Expired - Lifetime US3862420A (en) | 1973-11-01 | 1973-11-01 | System to prevent the formation of particulate material in corona units |
Country Status (7)
Country | Link |
---|---|
US (1) | US3862420A (en) |
JP (1) | JPS5828581B2 (en) |
CA (1) | CA1049089A (en) |
DE (1) | DE2448761A1 (en) |
FR (1) | FR2250216B1 (en) |
GB (1) | GB1444669A (en) |
IT (1) | IT1027571B (en) |
Cited By (36)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2651310A1 (en) * | 1975-11-11 | 1977-05-18 | Tokyo Shibaura Electric Co | ELECTROPHOTOGRAPHIC COPIER |
US4040731A (en) * | 1975-04-04 | 1977-08-09 | Olympus Optical Co., Ltd. | Electrophotographic apparatus having a screen-type photoconductive drum |
US4117778A (en) * | 1974-10-30 | 1978-10-03 | Oki Electric Industry Co., Ltd. | High speed printer with arc preventing fluorocarbon gas |
US4143118A (en) * | 1977-08-08 | 1979-03-06 | Xerox Corporation | Apparatus and method for ozone reduction in electrostatographic reproduction equipment |
US4197568A (en) * | 1977-06-20 | 1980-04-08 | Konishiroku Photo Industry Co., Ltd. | Corona generating apparatus |
US4250431A (en) * | 1979-12-26 | 1981-02-10 | Joseph Sugarman | Particulate collector apparatus and method for ion generators |
US4388274A (en) * | 1980-06-02 | 1983-06-14 | Xerox Corporation | Ozone collection and filtration system |
US4585323A (en) * | 1984-12-12 | 1986-04-29 | Xerox Corporation | Corona generating device |
US4585322A (en) * | 1984-12-12 | 1986-04-29 | Xerox Corporation | Corona generating device |
US4585320A (en) * | 1984-12-12 | 1986-04-29 | Xerox Corporation | Corona generating device |
US4646196A (en) * | 1985-07-01 | 1987-02-24 | Xerox Corporation | Corona generating device |
US4679924A (en) * | 1986-06-26 | 1987-07-14 | Wamsley Allen W | Corona discharge photography |
US4680040A (en) * | 1986-01-17 | 1987-07-14 | Xerox Corporation | Multipurpose filtering material |
US4734721A (en) * | 1985-10-04 | 1988-03-29 | Markem Corporation | Electrostatic printer utilizing dehumidified air |
US4745282A (en) * | 1982-04-20 | 1988-05-17 | Ricoh Company, Ltd. | Ventilated corona charging |
US4772901A (en) * | 1986-07-29 | 1988-09-20 | Markem Corporation | Electrostatic printing utilizing dehumidified air |
US4809026A (en) * | 1986-07-29 | 1989-02-28 | Markem Corporation | Electrostatic printing utilizing a heated air flow |
US4809027A (en) * | 1986-07-29 | 1989-02-28 | Markem Corporation | Offset electrostatic printing utilizing a heated air flow |
US4841146A (en) * | 1987-08-03 | 1989-06-20 | Xerox Corporation | Self-cleaning scorotron with focused ion beam |
US5012094A (en) * | 1990-02-05 | 1991-04-30 | Hamade Thomas A | Electrostatic charging apparatus and method |
DE4104321A1 (en) * | 1990-02-13 | 1991-08-14 | Ricoh Kk | DEVICE FOR ELIMINATING OZONE PRODUCED IN AN IMAGING DEVICE |
US5077468A (en) * | 1990-02-05 | 1991-12-31 | Hamade Thomas A | Electrostatic charging apparatus and method |
US5087943A (en) * | 1990-12-10 | 1992-02-11 | Eastman Kodak Company | Ozone removal system |
US5118942A (en) * | 1990-02-05 | 1992-06-02 | Hamade Thomas A | Electrostatic charging apparatus and method |
US5128720A (en) * | 1991-01-18 | 1992-07-07 | Eastman Kodak Company | Device for collecting contamination products and ozone from a corona charger |
US5264989A (en) * | 1991-06-14 | 1993-11-23 | Bauer William S | Apparatus for treating the surface of formed plastic articles using corona discharge |
DE4314942A1 (en) * | 1993-05-06 | 1994-11-10 | Ahlbrandt Andreas | Separator in particular for ozone from gas |
US5607647A (en) * | 1993-12-02 | 1997-03-04 | Extraction Systems, Inc. | Air filtering within clean environments |
EP1000587A1 (en) * | 1998-11-16 | 2000-05-17 | ATMOS MEDIZINTECHNIK GmbH & Co. | Suction device |
US6070026A (en) * | 1999-05-10 | 2000-05-30 | Xerox Corporation | Charging device with separate pressure and vacuum air flows |
US20020062836A1 (en) * | 2000-11-27 | 2002-05-30 | Matsushita Electric Works, Ltd. | Ion generator and hairbrush using the same |
US20050162136A1 (en) * | 2004-01-22 | 2005-07-28 | Tatsuya Kubo | Photoconductor charging device and image forming device using same |
EP1728545A1 (en) * | 2005-05-31 | 2006-12-06 | M+W Zander Holding AG | Process and filter for removing gaseous substances from gaseous media |
US20130165036A1 (en) * | 2011-12-27 | 2013-06-27 | Fuji Xerox Co., Ltd. | Blower pipe, blowing device, and image forming apparatus |
US20140186069A1 (en) * | 2012-12-27 | 2014-07-03 | Brother Kogyo Kabushiki Kaisha | Charging Device Configured to Produce Corona Discharge |
US10278617B1 (en) * | 2013-03-15 | 2019-05-07 | Invoy Holdings, Llc | Method and apparatus for sensing ammonia in breath |
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US4466813A (en) * | 1982-06-11 | 1984-08-21 | International Business Machines Corporation | Plasticizer removal process and system |
JPS6183431U (en) * | 1984-11-02 | 1986-06-02 |
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US3306011A (en) * | 1964-05-28 | 1967-02-28 | Dvorkin Harry | Air filter for inflatable tires |
US3471695A (en) * | 1967-05-22 | 1969-10-07 | Xerox Corp | Corona charging apparatus with means to urge a flow of aeriform fluid across the corona wires |
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US3324291A (en) * | 1964-07-06 | 1967-06-06 | Xerox Corp | Corona generating device with means to cause air flow therethrough to maintain the parts free of dust accumulation |
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DE2064544A1 (en) * | 1970-12-30 | 1972-07-27 | Kalle Ag | Method and device for increasing the service life of a photoconductor layer |
US3736424A (en) * | 1971-12-03 | 1973-05-29 | Ibm | Corona discharge device |
-
1973
- 1973-11-01 US US411987A patent/US3862420A/en not_active Expired - Lifetime
-
1974
- 1974-09-11 FR FR7431441A patent/FR2250216B1/fr not_active Expired
- 1974-09-19 IT IT27467/74A patent/IT1027571B/en active
- 1974-10-04 JP JP49113981A patent/JPS5828581B2/en not_active Expired
- 1974-10-11 GB GB4411774A patent/GB1444669A/en not_active Expired
- 1974-10-12 DE DE19742448761 patent/DE2448761A1/en not_active Withdrawn
- 1974-10-25 CA CA74212264A patent/CA1049089A/en not_active Expired
Patent Citations (2)
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US3306011A (en) * | 1964-05-28 | 1967-02-28 | Dvorkin Harry | Air filter for inflatable tires |
US3471695A (en) * | 1967-05-22 | 1969-10-07 | Xerox Corp | Corona charging apparatus with means to urge a flow of aeriform fluid across the corona wires |
Cited By (43)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4117778A (en) * | 1974-10-30 | 1978-10-03 | Oki Electric Industry Co., Ltd. | High speed printer with arc preventing fluorocarbon gas |
US4040731A (en) * | 1975-04-04 | 1977-08-09 | Olympus Optical Co., Ltd. | Electrophotographic apparatus having a screen-type photoconductive drum |
DE2651310A1 (en) * | 1975-11-11 | 1977-05-18 | Tokyo Shibaura Electric Co | ELECTROPHOTOGRAPHIC COPIER |
US4197568A (en) * | 1977-06-20 | 1980-04-08 | Konishiroku Photo Industry Co., Ltd. | Corona generating apparatus |
US4143118A (en) * | 1977-08-08 | 1979-03-06 | Xerox Corporation | Apparatus and method for ozone reduction in electrostatographic reproduction equipment |
US4250431A (en) * | 1979-12-26 | 1981-02-10 | Joseph Sugarman | Particulate collector apparatus and method for ion generators |
US4388274A (en) * | 1980-06-02 | 1983-06-14 | Xerox Corporation | Ozone collection and filtration system |
US4745282A (en) * | 1982-04-20 | 1988-05-17 | Ricoh Company, Ltd. | Ventilated corona charging |
US4585323A (en) * | 1984-12-12 | 1986-04-29 | Xerox Corporation | Corona generating device |
US4585322A (en) * | 1984-12-12 | 1986-04-29 | Xerox Corporation | Corona generating device |
US4585320A (en) * | 1984-12-12 | 1986-04-29 | Xerox Corporation | Corona generating device |
US4646196A (en) * | 1985-07-01 | 1987-02-24 | Xerox Corporation | Corona generating device |
US4734721A (en) * | 1985-10-04 | 1988-03-29 | Markem Corporation | Electrostatic printer utilizing dehumidified air |
US4680040A (en) * | 1986-01-17 | 1987-07-14 | Xerox Corporation | Multipurpose filtering material |
US4679924A (en) * | 1986-06-26 | 1987-07-14 | Wamsley Allen W | Corona discharge photography |
US4772901A (en) * | 1986-07-29 | 1988-09-20 | Markem Corporation | Electrostatic printing utilizing dehumidified air |
US4809026A (en) * | 1986-07-29 | 1989-02-28 | Markem Corporation | Electrostatic printing utilizing a heated air flow |
US4809027A (en) * | 1986-07-29 | 1989-02-28 | Markem Corporation | Offset electrostatic printing utilizing a heated air flow |
US4841146A (en) * | 1987-08-03 | 1989-06-20 | Xerox Corporation | Self-cleaning scorotron with focused ion beam |
US5012094A (en) * | 1990-02-05 | 1991-04-30 | Hamade Thomas A | Electrostatic charging apparatus and method |
US5118942A (en) * | 1990-02-05 | 1992-06-02 | Hamade Thomas A | Electrostatic charging apparatus and method |
US5077468A (en) * | 1990-02-05 | 1991-12-31 | Hamade Thomas A | Electrostatic charging apparatus and method |
DE4104321A1 (en) * | 1990-02-13 | 1991-08-14 | Ricoh Kk | DEVICE FOR ELIMINATING OZONE PRODUCED IN AN IMAGING DEVICE |
US5128110A (en) * | 1990-02-13 | 1992-07-07 | Ricoh Company, Ltd. | Ozone removing device for image forming equipment |
DE4104321C2 (en) * | 1990-02-13 | 1992-08-06 | Ricoh Co., Ltd., Tokio/Tokyo, Jp | |
US5087943A (en) * | 1990-12-10 | 1992-02-11 | Eastman Kodak Company | Ozone removal system |
US5128720A (en) * | 1991-01-18 | 1992-07-07 | Eastman Kodak Company | Device for collecting contamination products and ozone from a corona charger |
US5264989A (en) * | 1991-06-14 | 1993-11-23 | Bauer William S | Apparatus for treating the surface of formed plastic articles using corona discharge |
DE4314942A1 (en) * | 1993-05-06 | 1994-11-10 | Ahlbrandt Andreas | Separator in particular for ozone from gas |
US5607647A (en) * | 1993-12-02 | 1997-03-04 | Extraction Systems, Inc. | Air filtering within clean environments |
EP1000587A1 (en) * | 1998-11-16 | 2000-05-17 | ATMOS MEDIZINTECHNIK GmbH & Co. | Suction device |
US6070026A (en) * | 1999-05-10 | 2000-05-30 | Xerox Corporation | Charging device with separate pressure and vacuum air flows |
US6907888B2 (en) * | 2000-11-27 | 2005-06-21 | Matsushita Electric Works, Ltd. | Ion generator and hairbrush using the same |
US20020062836A1 (en) * | 2000-11-27 | 2002-05-30 | Matsushita Electric Works, Ltd. | Ion generator and hairbrush using the same |
US20050162136A1 (en) * | 2004-01-22 | 2005-07-28 | Tatsuya Kubo | Photoconductor charging device and image forming device using same |
US7421222B2 (en) * | 2004-01-22 | 2008-09-02 | Ricoh Printing Systems, Ltd. | Electrophotographic device with contaminant-resistant photoconductor and charger |
EP1728545A1 (en) * | 2005-05-31 | 2006-12-06 | M+W Zander Holding AG | Process and filter for removing gaseous substances from gaseous media |
US20070065951A1 (en) * | 2005-05-31 | 2007-03-22 | Mzander Holding Ag | Method for Separating Gaseous Components from Gaseous Media and Filter for Performing the Method |
US20130165036A1 (en) * | 2011-12-27 | 2013-06-27 | Fuji Xerox Co., Ltd. | Blower pipe, blowing device, and image forming apparatus |
US9658558B2 (en) * | 2011-12-27 | 2017-05-23 | Fuji Xerox Co., Ltd. | Blower pipe, blowing device, and image forming apparatus |
US20140186069A1 (en) * | 2012-12-27 | 2014-07-03 | Brother Kogyo Kabushiki Kaisha | Charging Device Configured to Produce Corona Discharge |
US8965249B2 (en) * | 2012-12-27 | 2015-02-24 | Brother Kogyo Kabushiki Kaisha | Charging device configured to produce corona discharge |
US10278617B1 (en) * | 2013-03-15 | 2019-05-07 | Invoy Holdings, Llc | Method and apparatus for sensing ammonia in breath |
Also Published As
Publication number | Publication date |
---|---|
IT1027571B (en) | 1978-12-20 |
JPS5828581B2 (en) | 1983-06-16 |
DE2448761A1 (en) | 1975-05-07 |
JPS5075441A (en) | 1975-06-20 |
FR2250216B1 (en) | 1976-10-22 |
CA1049089A (en) | 1979-02-20 |
GB1444669A (en) | 1976-08-04 |
FR2250216A1 (en) | 1975-05-30 |
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