CA1042655A - Magnetic brush roll having resilient polymeric surface - Google Patents
Magnetic brush roll having resilient polymeric surfaceInfo
- Publication number
- CA1042655A CA1042655A CA215,044A CA215044A CA1042655A CA 1042655 A CA1042655 A CA 1042655A CA 215044 A CA215044 A CA 215044A CA 1042655 A CA1042655 A CA 1042655A
- Authority
- CA
- Canada
- Prior art keywords
- magnetic brush
- roll
- brush roll
- resilient
- resilient polymeric
- 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
Links
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
- G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
- G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration
- G03G15/0928—Details concerning the magnetic brush roller structure, e.g. magnet configuration relating to the shell, e.g. structure, composition
Abstract
MAGNETIC BRUSH ROLL HAVING RESILIENT POLYMERIC SURFACE
Abstract of the Disclosure A magnetic brush roll of an electrostatic reproduction machine is formed of a non-magnetic core with a resilient polymeric material such as polyurethane, for example, on its surface. The polyurethane surface is textured to provide a desired roughness, is non-abrasive, and is abrasion resistant. Carbon is added to the polyurethane to render it conductive.
Abstract of the Disclosure A magnetic brush roll of an electrostatic reproduction machine is formed of a non-magnetic core with a resilient polymeric material such as polyurethane, for example, on its surface. The polyurethane surface is textured to provide a desired roughness, is non-abrasive, and is abrasion resistant. Carbon is added to the polyurethane to render it conductive.
Description
~04Z65S
1 Specification In well-known electrostatic printing processes, a surface bearing a latent electrostatic image is developed by applying a developer material comprising toner and a carrier material to the surface.
The small toner particles are held onto the surfaces of the relatively larger carrier particles by electrostatic forces, which develop from the contact between the toner and carrier particles producing tri-boelectric charging of the toner and carrier to opposite polarities.
A portion of the applied triboelectrically charged toner is selec-tively attracted to the image areas of the surface, and the remainderof the developer material is removed and allowed to recirculate to form subsequent images.
In order to assure clear, sharp images, it is necessary that the toner obtain a high triboelectric charge prior to development. This has generally been effected in prior devices by selecting toner and carrier materials which are widely separated in the triboelectric series and by causing agitation and stirring of the developer material prior to development. Further, the ratio of toner to carrier in the developer material or mix is closely controlled. However, even when the most optimum materials and mixing devices are utilized, the triboelectric charge of the toner for a given toner-carrier ratio is often insufficient to provide uniform high quality copy output.
~04Z65S
1 Various prior art developing mechanisms ;ncorporate a magnetic brush comprising a cylindrical member or roll rotatably mounted relative to a fixed magnetic field generating means onto which multicomponent magnetic developer material is delivered. The magnetic field generating means creates a magnetic field causing the magnetic developer to form in bristle-like arrays over the surface of the cylindrical member or roll as it is rotated into contact with an electrostatic latent image-bearing surface.
For the surface of a magnetic brush roll to transport the mag-netic developer to an electrostatic latent image-bearing surface, it has previously been suggested in U.S. patent 3,040,704 to Bliss to form the roll with a roughened external surface. However, attempts to roughen the surface of the roll, which is formed of a non-magnetic material such as aluminum, brass, or other soft alloy, by cutting grooves, serrations, or knurls therein have resulted in the surface being rapidly worn down by the abrasive action of the developer material.
It also has been previously suggested in U.S. patent 3,219,014 LE9-73-01~ - 2 -1 to Mott et al to sandblast the surface of a magnetic brush roll to roughen the surface in a uniform pattern. However, sandblasting does not make the surface rough enough. Furthermore, the wear of the sand-blasted surface results in polished high spots to reduce the transport capability for the developer material by the sandblasted surface.
Instead of forming the roughened surface directly in the magnetic brush roll by grooves, serrations, knurls, or sandblasting, it has previously been suggested in U.S. patent 3,246,629 to Shelffo to bond a layer of irregular shaped particles to the surface of the magnetic brush roll. This provides a random roughened surface.
In transporting the developer material to the electrostatic latent image-bearing surface, the developer material is moved either uphill or downhill depending on how the entire machine is arranged.
When the developer material is moved uphill, the surface of the magnetic brush roll must be rough enough to enable the carrier par-ticles to not slide relative thereto while being advanced uphill by the magnetic brush roll.
While the magnetic brush roll of the aforesaid Shelffo patent provides a roughened surface, this surface lacks the desired properties of being non-abrasive and resilient. The abrasive surface of the magnetic brush roll of the aforesaid Shelffo patent causes wear on the carrier particles of the developer material, particularly in the slight clearance area between the magnetic brush roll and the electro-static latent image-bearing surface since the abrasive surface causes the carrier particles to rub against each other and against the surface of the magnetic brush roll. Lack or resiliency in the surface of the magnetic brush roll of the aforesaid Shelffo patent prevents the sur-face of the magnetic brush roll from giving to a slight degree when a plurality of the carrier particles are disposed in engagement with each other between the magnetic brush roll and the electrostatic latent image-bearing surface with a slightly greater overall distance than the clearance.
LE9-73-012 - 3 _ 1 The present invention satisfactorily solves the foregoing pro-blems by providing a roughened surface which is both resilient and non-abrasive as well as being abrasion resistant. The resilient and non-abrasive surface of the magnetic brush roll of the present in-vention increases the life of the carrier particles by reducing wear of the carrier particles. Thus, wear on the carrier particles is reduced not only by the non-abrasive surface of the magnetic brush roll of the present invention, but its resiliency prevents wear when the carrier particles are within the clearance area in which they tend to have the greatest rubbing relation with the magnetic brush roll and with each other.
Even though the surface of the magnetic brush roll of the present invention is both resilient and non-abrasive~ it still is rough. As a result, it provides the desired surface to enable the magnet;c brush roll to advance the developer material or mix in an uphill direction so that the carrier particles, which have the toner par-ticles thereon, are advanced to the clearance area between the mag-netic brush roll and the electrostatic latent image-bearing surface.
The present invention provides the improved magnetic brush roll through having a resilient polymeric material secured to a non-magnetic core. Because it is necessary to have a bias on the magnetic brush roll, at least the surface of the resilient polymeric material must be conductive. In its preferred form, the resilient polymeric material of the magnetic brush roll of the present invention is homo-geneous and conductive throughout.
An object of this invention is to provide a magnetic brush roll having a non-abrasive and resilient surface that is rough or tex-tured.
Another object of this invention is to provide a magnetic brush roll having a resilient polymeric material as its surface.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular 1 description of preferred embodiments of the invention, as illustrated in the accompanying drawing.
In the drawing:
FIGURE 1 is a schematic sectional view of a portion of an electro-static reproduction machine having the magnetic brush roll of the present invention.
FIGURE 2 is a fragmentary perspective view of a portion of one form of the magnetic brush roll of the present invention.
FIGURE 3 is a fragmentary sectional view of another form of the magnetic brush roll of the present invention.
Referring to the drawing and particularly FIGURE 1, there is shown a portion of an electrostatic reproduction machine 10 having a photoconductor drum 11, which functions as the electrostatic latent image-bearing surface. The photoconductor drum 11 is rotated clock-wise by being driven from a main power source.
The developer material, which comprises a mix of carrier parti-cles and toner part;cles, is stored in a sump portion 14 of a magnetic brush developer station 15. The toner particles are supplied to the sump portion 14 from a toner cartridge (not shown) by a metering cylinder (not shown) of a replenisher (not shown), which has an agitator (not shown), through an opening 16 in the magnetic brush developer station 15 to the sump portion 14 of the magnetic brush developer station 15. Counter rotating augers 17 and 18 stir the freshly added toner with the developer material in the sump portion 14 to assure complete mixing thereof as well as to enhance the triboelectric charging of the developer material.
The developer material is metered from the sump portion 14 to a transport portion 19 of the magnetic brush developer station 15 by a metering gate 20. The transport portion 19 of the magnetic brush developer station 15 ~as a transport roll 21 disposed therein beneath a magnetic brush roll 22.
The transport roll 21, which rotates at a speed less than the ~042655 rotational speed of the magnetic brush roll 22 to provide a surface velocity of the transport roll 21 no greater than the surface velo-city of the magnetic brush roll 22, rotates clockwise while the mag-netic brush roll 22 rotates counterclockwise. The transport roll 21 surrounds a fixed drum 23 which has magnets 24 on a portion of the surface thereof to aid in holding the developer material on the trans-port roll 21 until the developer material is advanced to a position adjacent the oppositely rotating magnetic brush roll 22.
As the developer material is advanced by the transport roll 21 to the magnetic brush roll 22, the developer material is attracted to the magnetic brush roll 22 by magnets 25, which are fixed and disposed within the magnetic brush roll 22. The magnets 25 may be of any suitable type as long as they cause the developer material to adhere to the magnetic brush roll 22 and have a bristle-like array adjacent the photoconductor 11.
As shown in FIGURE 2, the magnetic brush roll 22 includes a core 26 of a non-magnetic material such as aluminum, for example. The core 26 is closed at its ends by plates 27.
A shaft 28 extends from the plate 27 at one end of the core 26 and is driven from a main power source by a chain passing around a sprocket on the shaft 28. The transport roll 21 is driven in unison with the magnetic brush roll 22 through the same chain cooperating with a shaft 29 of the transport roll 21. The other plate 27 is rotatably supported by a bearing on a fixed shaft 30 (see FIGURE 1) on which the magnets 25 are supported.
The core 26 of the magnetic brush roll 22 has a sleeve 31 of a resilient polymeric material secured thereto. The sleeve 31 has its surface textured so as to be roughened to a desired extent. The roughness pattern in the sleeve 31 can be uniform or non-uniform.
One suitable example of the resilient polymeric material of the sleeve 31 is polyurethane. The sleeve 31 is homogeneous and is conductive so that a desired bias can be applied to the magnetic 1 brush roll 22. ~hile polyurethane is not conductive, carbon is added thereto to insure that the sleeve 31 is conductive.
One means of forming the sleeve 3i is to use Norton Company's AH299 grinding tube as a mold. The tube is machined to an outer diameter of 2.4 inches and then grit blasted to produce a random, textured surface on the tube as the mold. Then, DuPont 958-202 steel blue Teflon** release coat is applied to the surface of the mold.
The mold is then dip coated twelve times within a conductive polyurethane solution with the mold being inverted after each of the dips. The conductive polyurethane solution is prepared by adding one hundred parts by weight of Hughson Chemical Company's TS-1525-37 urethane lacquer resin, 8.3 parts by weight of Cabot Corporation's Vulcan* XC-72 conductive carbon black, 100 parts by weight of toluene, and 100 parts by weight of isopropyl alchohol with-in an attritor and running the attritor at full speed for one hour~
After each coating of the conductive polyurethane solution is formed on the mold, it is air dryed for at least fifteen minutes before an additional coat is applied by dipping. After every fourth dip and after air drying, the mold is placed in an air circulating oven and allowed to dry for at least fifteen minutes at 150 F to remove any residual solvent.
This forms the sleeve 31, which is removed from the mold. After turning the sleeve 31 inside out, the sleeve 31 is deposited over the core 26, which has been adhesive coated by spray coating with EC2290 modified epoxy adhesive of 3M and completely dried. The sleeve 31 is expanded by air to be able to fit over the core 26. After the sleeve 31 has been disposed over the core 26, it is cured for one hour at 300 F.
Tests have indicated that the tensile strength of the sleeve 31 is 4,000 p.s.i. with an ultimate elongation in excess of 800 per cent. 0 The tear strength of the sleeve 31 is 330 pounds per inch thickness, * Trade Mark *** Registered Trade Mark ~04Z655 1 and it has a hardness of 65 on a shore A durometer. Its volume resisti-vity is 104 ohm-cm.
Accordingly, the magnetic brush roll 22 has a surface, which is rough or textured, non-abrasive, and abrasion resistant. At the same time, the sleeve 31 is resilient and is conductive throughout. This permits the required bias to be applied to the magnetic brush roll 22.
As the magnetic brush roll 22 advances the developer material toward the photoconductor drum 11, it passes a bead control device 32. The bead control device 32 limits the thickness of the developer material on the magnetic brush roll 22 prior to being advanced into the position adjacent the photoconductor drum 11.
The magnetic brush developer station 15 supports a pile fabric seal 33, which is made of a material such as Kodel*, for example. The purpose of the seal 33, which engages the photoconductor drum 11, is to prevent a toner cloud from escaping from the magnetic brush develo-per station 15.
After the magnetic brush roll 22 has advanced the developer material past the photoconductor drum 11, the developer material remaining on the magnetic brush roll 22 is released after passing the last of the magnets 25 and returned to the sump portion 14 of the magnetic brush developer station 15.
The magnetic brush developer station 15 also supports a blade scraper 34, which is conductive coated Mylar, adjacent the photo-conductor drum 11 and spaced slightly therefrom. The purpose of the blade scraper 34 is to keep the toner and carrier particles from escaping from the magnetic brush deve10per station 15.
A seal 35, which is spaced slightly from the photoconductor drum 11, also is supported by the magnetic brush developer station 15 and is passed by the photoconductor drum 11 after the photoconductor drum 11 moves past the scraper 34. The seal 35, which also is * Trade Mark 1104'~655 1 conductive coated Mylar**, likewise functions to keep the toner and carrier particles from escaping from the magnetic brush developer sta-tion 15.
Instead of the magnetic brush roll 22 having the sleeve 31, which is homogeneous polyurethane with carbon, a magnetic brush roll 37 (see FIGURE 3) could be employed in which the core 26 would again be used. The core 26 would have a layer 38 of polyurethane without carbon thereon so that the layer 38 would not be conductive. Then, a layer 39 of polyurethane with carbon could be applied to the layer 38 by being painted thereon. The layer 39 would need to be only about .001" thick.
Thus, the magnetic brush roll 37 would be conductive only along its surface. However, this is sufficient to provide the desired bias thereon.
The sleeve 31 of the magnetic brush roll 22 or the layer 38 of the magnetic brush roll 37 must be at least .010" thick and is pre-ferably at least .015" thick. While the sleeve 31 of the magnetic brush roll 22 or the layer 39 of the magnetic brush roll 37 has a hardness of 65 on a Shore A durometer, it should be understood that either could have a hardness up to 95 on a Shore A durometer and still have sufficient resiliency.
While the resilient polymeric material has been described as being polyurethane, it should be understood that any other resilient poly-meric material having the desired properties could be employed. This includes the capability of having a conductive material such as carbon, for example, added without the material losing its other desired pro-perties of being resilient, non-abrasive, and abrasion resistant. Thus, any synthetic rubber having the properties of being resilient, non-abrasive, and abrasion resistant could be utilized, for example, The rubber could be dip-coated on a textured core of a non-magnetic material, for example, to have the desired roughness. It is necessary that any ** Registered Trade Mark 1 resilient polymeric material be non-abrasive and abrasion resistant as well as having a sufficient roughness to permit the developer material to have a foothold on the magnetic brush roll.
While the roughness of the material can be within varying ranges, it is preferred that the roughness be no greater than that produced by a molding from a fifty grit sandpaper. The roughness preferably is no less than that produced by ninety grit sandpaper.
While the sleeve 31 has been described as being formed through a dipping process on a mold and then removing the sleeve 31 for appli-cation on the core 26, it should be understood that any other suitable process could be employed. For example, the material could be injection molded around a core or a sleeve could be extruded with the material having to be thermoplastic in nature to allow the desired roughness to be embossed in its surface.
While the present invention has been shown and described as having the developer material moved uphill by the magnetic brush roll, it should be understood that the magnetic brush roll of the present invention could be utilized where the developer material is moved downhill. This would be particularly useful in a relatively high speed machine.
An advantage of this invention is that it reduces the wear of the developer material. Another advantage of this invention is that it is particularly useful in moving a material uphill to an electrostatic latent image-bearing surface.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be under-stood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.
1 Specification In well-known electrostatic printing processes, a surface bearing a latent electrostatic image is developed by applying a developer material comprising toner and a carrier material to the surface.
The small toner particles are held onto the surfaces of the relatively larger carrier particles by electrostatic forces, which develop from the contact between the toner and carrier particles producing tri-boelectric charging of the toner and carrier to opposite polarities.
A portion of the applied triboelectrically charged toner is selec-tively attracted to the image areas of the surface, and the remainderof the developer material is removed and allowed to recirculate to form subsequent images.
In order to assure clear, sharp images, it is necessary that the toner obtain a high triboelectric charge prior to development. This has generally been effected in prior devices by selecting toner and carrier materials which are widely separated in the triboelectric series and by causing agitation and stirring of the developer material prior to development. Further, the ratio of toner to carrier in the developer material or mix is closely controlled. However, even when the most optimum materials and mixing devices are utilized, the triboelectric charge of the toner for a given toner-carrier ratio is often insufficient to provide uniform high quality copy output.
~04Z65S
1 Various prior art developing mechanisms ;ncorporate a magnetic brush comprising a cylindrical member or roll rotatably mounted relative to a fixed magnetic field generating means onto which multicomponent magnetic developer material is delivered. The magnetic field generating means creates a magnetic field causing the magnetic developer to form in bristle-like arrays over the surface of the cylindrical member or roll as it is rotated into contact with an electrostatic latent image-bearing surface.
For the surface of a magnetic brush roll to transport the mag-netic developer to an electrostatic latent image-bearing surface, it has previously been suggested in U.S. patent 3,040,704 to Bliss to form the roll with a roughened external surface. However, attempts to roughen the surface of the roll, which is formed of a non-magnetic material such as aluminum, brass, or other soft alloy, by cutting grooves, serrations, or knurls therein have resulted in the surface being rapidly worn down by the abrasive action of the developer material.
It also has been previously suggested in U.S. patent 3,219,014 LE9-73-01~ - 2 -1 to Mott et al to sandblast the surface of a magnetic brush roll to roughen the surface in a uniform pattern. However, sandblasting does not make the surface rough enough. Furthermore, the wear of the sand-blasted surface results in polished high spots to reduce the transport capability for the developer material by the sandblasted surface.
Instead of forming the roughened surface directly in the magnetic brush roll by grooves, serrations, knurls, or sandblasting, it has previously been suggested in U.S. patent 3,246,629 to Shelffo to bond a layer of irregular shaped particles to the surface of the magnetic brush roll. This provides a random roughened surface.
In transporting the developer material to the electrostatic latent image-bearing surface, the developer material is moved either uphill or downhill depending on how the entire machine is arranged.
When the developer material is moved uphill, the surface of the magnetic brush roll must be rough enough to enable the carrier par-ticles to not slide relative thereto while being advanced uphill by the magnetic brush roll.
While the magnetic brush roll of the aforesaid Shelffo patent provides a roughened surface, this surface lacks the desired properties of being non-abrasive and resilient. The abrasive surface of the magnetic brush roll of the aforesaid Shelffo patent causes wear on the carrier particles of the developer material, particularly in the slight clearance area between the magnetic brush roll and the electro-static latent image-bearing surface since the abrasive surface causes the carrier particles to rub against each other and against the surface of the magnetic brush roll. Lack or resiliency in the surface of the magnetic brush roll of the aforesaid Shelffo patent prevents the sur-face of the magnetic brush roll from giving to a slight degree when a plurality of the carrier particles are disposed in engagement with each other between the magnetic brush roll and the electrostatic latent image-bearing surface with a slightly greater overall distance than the clearance.
LE9-73-012 - 3 _ 1 The present invention satisfactorily solves the foregoing pro-blems by providing a roughened surface which is both resilient and non-abrasive as well as being abrasion resistant. The resilient and non-abrasive surface of the magnetic brush roll of the present in-vention increases the life of the carrier particles by reducing wear of the carrier particles. Thus, wear on the carrier particles is reduced not only by the non-abrasive surface of the magnetic brush roll of the present invention, but its resiliency prevents wear when the carrier particles are within the clearance area in which they tend to have the greatest rubbing relation with the magnetic brush roll and with each other.
Even though the surface of the magnetic brush roll of the present invention is both resilient and non-abrasive~ it still is rough. As a result, it provides the desired surface to enable the magnet;c brush roll to advance the developer material or mix in an uphill direction so that the carrier particles, which have the toner par-ticles thereon, are advanced to the clearance area between the mag-netic brush roll and the electrostatic latent image-bearing surface.
The present invention provides the improved magnetic brush roll through having a resilient polymeric material secured to a non-magnetic core. Because it is necessary to have a bias on the magnetic brush roll, at least the surface of the resilient polymeric material must be conductive. In its preferred form, the resilient polymeric material of the magnetic brush roll of the present invention is homo-geneous and conductive throughout.
An object of this invention is to provide a magnetic brush roll having a non-abrasive and resilient surface that is rough or tex-tured.
Another object of this invention is to provide a magnetic brush roll having a resilient polymeric material as its surface.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular 1 description of preferred embodiments of the invention, as illustrated in the accompanying drawing.
In the drawing:
FIGURE 1 is a schematic sectional view of a portion of an electro-static reproduction machine having the magnetic brush roll of the present invention.
FIGURE 2 is a fragmentary perspective view of a portion of one form of the magnetic brush roll of the present invention.
FIGURE 3 is a fragmentary sectional view of another form of the magnetic brush roll of the present invention.
Referring to the drawing and particularly FIGURE 1, there is shown a portion of an electrostatic reproduction machine 10 having a photoconductor drum 11, which functions as the electrostatic latent image-bearing surface. The photoconductor drum 11 is rotated clock-wise by being driven from a main power source.
The developer material, which comprises a mix of carrier parti-cles and toner part;cles, is stored in a sump portion 14 of a magnetic brush developer station 15. The toner particles are supplied to the sump portion 14 from a toner cartridge (not shown) by a metering cylinder (not shown) of a replenisher (not shown), which has an agitator (not shown), through an opening 16 in the magnetic brush developer station 15 to the sump portion 14 of the magnetic brush developer station 15. Counter rotating augers 17 and 18 stir the freshly added toner with the developer material in the sump portion 14 to assure complete mixing thereof as well as to enhance the triboelectric charging of the developer material.
The developer material is metered from the sump portion 14 to a transport portion 19 of the magnetic brush developer station 15 by a metering gate 20. The transport portion 19 of the magnetic brush developer station 15 ~as a transport roll 21 disposed therein beneath a magnetic brush roll 22.
The transport roll 21, which rotates at a speed less than the ~042655 rotational speed of the magnetic brush roll 22 to provide a surface velocity of the transport roll 21 no greater than the surface velo-city of the magnetic brush roll 22, rotates clockwise while the mag-netic brush roll 22 rotates counterclockwise. The transport roll 21 surrounds a fixed drum 23 which has magnets 24 on a portion of the surface thereof to aid in holding the developer material on the trans-port roll 21 until the developer material is advanced to a position adjacent the oppositely rotating magnetic brush roll 22.
As the developer material is advanced by the transport roll 21 to the magnetic brush roll 22, the developer material is attracted to the magnetic brush roll 22 by magnets 25, which are fixed and disposed within the magnetic brush roll 22. The magnets 25 may be of any suitable type as long as they cause the developer material to adhere to the magnetic brush roll 22 and have a bristle-like array adjacent the photoconductor 11.
As shown in FIGURE 2, the magnetic brush roll 22 includes a core 26 of a non-magnetic material such as aluminum, for example. The core 26 is closed at its ends by plates 27.
A shaft 28 extends from the plate 27 at one end of the core 26 and is driven from a main power source by a chain passing around a sprocket on the shaft 28. The transport roll 21 is driven in unison with the magnetic brush roll 22 through the same chain cooperating with a shaft 29 of the transport roll 21. The other plate 27 is rotatably supported by a bearing on a fixed shaft 30 (see FIGURE 1) on which the magnets 25 are supported.
The core 26 of the magnetic brush roll 22 has a sleeve 31 of a resilient polymeric material secured thereto. The sleeve 31 has its surface textured so as to be roughened to a desired extent. The roughness pattern in the sleeve 31 can be uniform or non-uniform.
One suitable example of the resilient polymeric material of the sleeve 31 is polyurethane. The sleeve 31 is homogeneous and is conductive so that a desired bias can be applied to the magnetic 1 brush roll 22. ~hile polyurethane is not conductive, carbon is added thereto to insure that the sleeve 31 is conductive.
One means of forming the sleeve 3i is to use Norton Company's AH299 grinding tube as a mold. The tube is machined to an outer diameter of 2.4 inches and then grit blasted to produce a random, textured surface on the tube as the mold. Then, DuPont 958-202 steel blue Teflon** release coat is applied to the surface of the mold.
The mold is then dip coated twelve times within a conductive polyurethane solution with the mold being inverted after each of the dips. The conductive polyurethane solution is prepared by adding one hundred parts by weight of Hughson Chemical Company's TS-1525-37 urethane lacquer resin, 8.3 parts by weight of Cabot Corporation's Vulcan* XC-72 conductive carbon black, 100 parts by weight of toluene, and 100 parts by weight of isopropyl alchohol with-in an attritor and running the attritor at full speed for one hour~
After each coating of the conductive polyurethane solution is formed on the mold, it is air dryed for at least fifteen minutes before an additional coat is applied by dipping. After every fourth dip and after air drying, the mold is placed in an air circulating oven and allowed to dry for at least fifteen minutes at 150 F to remove any residual solvent.
This forms the sleeve 31, which is removed from the mold. After turning the sleeve 31 inside out, the sleeve 31 is deposited over the core 26, which has been adhesive coated by spray coating with EC2290 modified epoxy adhesive of 3M and completely dried. The sleeve 31 is expanded by air to be able to fit over the core 26. After the sleeve 31 has been disposed over the core 26, it is cured for one hour at 300 F.
Tests have indicated that the tensile strength of the sleeve 31 is 4,000 p.s.i. with an ultimate elongation in excess of 800 per cent. 0 The tear strength of the sleeve 31 is 330 pounds per inch thickness, * Trade Mark *** Registered Trade Mark ~04Z655 1 and it has a hardness of 65 on a shore A durometer. Its volume resisti-vity is 104 ohm-cm.
Accordingly, the magnetic brush roll 22 has a surface, which is rough or textured, non-abrasive, and abrasion resistant. At the same time, the sleeve 31 is resilient and is conductive throughout. This permits the required bias to be applied to the magnetic brush roll 22.
As the magnetic brush roll 22 advances the developer material toward the photoconductor drum 11, it passes a bead control device 32. The bead control device 32 limits the thickness of the developer material on the magnetic brush roll 22 prior to being advanced into the position adjacent the photoconductor drum 11.
The magnetic brush developer station 15 supports a pile fabric seal 33, which is made of a material such as Kodel*, for example. The purpose of the seal 33, which engages the photoconductor drum 11, is to prevent a toner cloud from escaping from the magnetic brush develo-per station 15.
After the magnetic brush roll 22 has advanced the developer material past the photoconductor drum 11, the developer material remaining on the magnetic brush roll 22 is released after passing the last of the magnets 25 and returned to the sump portion 14 of the magnetic brush developer station 15.
The magnetic brush developer station 15 also supports a blade scraper 34, which is conductive coated Mylar, adjacent the photo-conductor drum 11 and spaced slightly therefrom. The purpose of the blade scraper 34 is to keep the toner and carrier particles from escaping from the magnetic brush deve10per station 15.
A seal 35, which is spaced slightly from the photoconductor drum 11, also is supported by the magnetic brush developer station 15 and is passed by the photoconductor drum 11 after the photoconductor drum 11 moves past the scraper 34. The seal 35, which also is * Trade Mark 1104'~655 1 conductive coated Mylar**, likewise functions to keep the toner and carrier particles from escaping from the magnetic brush developer sta-tion 15.
Instead of the magnetic brush roll 22 having the sleeve 31, which is homogeneous polyurethane with carbon, a magnetic brush roll 37 (see FIGURE 3) could be employed in which the core 26 would again be used. The core 26 would have a layer 38 of polyurethane without carbon thereon so that the layer 38 would not be conductive. Then, a layer 39 of polyurethane with carbon could be applied to the layer 38 by being painted thereon. The layer 39 would need to be only about .001" thick.
Thus, the magnetic brush roll 37 would be conductive only along its surface. However, this is sufficient to provide the desired bias thereon.
The sleeve 31 of the magnetic brush roll 22 or the layer 38 of the magnetic brush roll 37 must be at least .010" thick and is pre-ferably at least .015" thick. While the sleeve 31 of the magnetic brush roll 22 or the layer 39 of the magnetic brush roll 37 has a hardness of 65 on a Shore A durometer, it should be understood that either could have a hardness up to 95 on a Shore A durometer and still have sufficient resiliency.
While the resilient polymeric material has been described as being polyurethane, it should be understood that any other resilient poly-meric material having the desired properties could be employed. This includes the capability of having a conductive material such as carbon, for example, added without the material losing its other desired pro-perties of being resilient, non-abrasive, and abrasion resistant. Thus, any synthetic rubber having the properties of being resilient, non-abrasive, and abrasion resistant could be utilized, for example, The rubber could be dip-coated on a textured core of a non-magnetic material, for example, to have the desired roughness. It is necessary that any ** Registered Trade Mark 1 resilient polymeric material be non-abrasive and abrasion resistant as well as having a sufficient roughness to permit the developer material to have a foothold on the magnetic brush roll.
While the roughness of the material can be within varying ranges, it is preferred that the roughness be no greater than that produced by a molding from a fifty grit sandpaper. The roughness preferably is no less than that produced by ninety grit sandpaper.
While the sleeve 31 has been described as being formed through a dipping process on a mold and then removing the sleeve 31 for appli-cation on the core 26, it should be understood that any other suitable process could be employed. For example, the material could be injection molded around a core or a sleeve could be extruded with the material having to be thermoplastic in nature to allow the desired roughness to be embossed in its surface.
While the present invention has been shown and described as having the developer material moved uphill by the magnetic brush roll, it should be understood that the magnetic brush roll of the present invention could be utilized where the developer material is moved downhill. This would be particularly useful in a relatively high speed machine.
An advantage of this invention is that it reduces the wear of the developer material. Another advantage of this invention is that it is particularly useful in moving a material uphill to an electrostatic latent image-bearing surface.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be under-stood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (10)
1. In an electrophotographic development apparatus of the magnetic brush type having:
a surface on which a latent image is formed;
a rotatably mounted hollow roll including a core of non-magnetic material and a resilient polymeric material secured to said core to form the surface of said roll;
said resilient polymeric material having at least its surface electrically conductive;
said resilient polymeric material having its surface non-abrasive, abrasion resistant, and rough;
magnetic means disposed within said core for creating a magnetic field in the path of the periphery of said roll;
and means to bring a developer material into contact with the surface of said resilient polymeric material of said roll, said roll being disposed and adjacent said surface on which the latent image is formed so that said roll can transport the developer material in a brush-like configuration to the surface on which the latent image is formed.
a surface on which a latent image is formed;
a rotatably mounted hollow roll including a core of non-magnetic material and a resilient polymeric material secured to said core to form the surface of said roll;
said resilient polymeric material having at least its surface electrically conductive;
said resilient polymeric material having its surface non-abrasive, abrasion resistant, and rough;
magnetic means disposed within said core for creating a magnetic field in the path of the periphery of said roll;
and means to bring a developer material into contact with the surface of said resilient polymeric material of said roll, said roll being disposed and adjacent said surface on which the latent image is formed so that said roll can transport the developer material in a brush-like configuration to the surface on which the latent image is formed.
2. The apparatus according to claim 1 in which said resilient polymeric material of said roll is electrically conductive throughout its entirety.
3. The apparatus according to claim 2 in which said resilient poly-meric material comprises a single homogeneous layer on said core.
4. The apparatus according to claim 3 in which said resilient poly-meric material has a hardness no greater than 95 on a Shore A durometer.
5. The apparatus according to claim 5 in which said layer of resilient polymeric material is at least .010" thick.
6. The apparatus according to claim 5 in which said layer of resilient polymeric material is polyurethane having an electrically conductive material disposed throughout.
7. The apparatus according to claim 2 in which said resilient poly-meric material comprises:
a first homogeneous layer secured to said core;
and a second layer secured to said first layer, said second layer being electrically conductive.
a first homogeneous layer secured to said core;
and a second layer secured to said first layer, said second layer being electrically conductive.
8. The apparatus according to claim 7 in which:
said resilient polymeric material is polyurethane;
and said second layer includes an electrically conductive material in said polyurethane.
said resilient polymeric material is polyurethane;
and said second layer includes an electrically conductive material in said polyurethane.
9. The apparatus according to claim 8 in which said resilient poly-meric material has a hardness no greater than 95 on a Shore A durometer.
10. The apparatus according to claim 1 in which said resilient polymeric material is polyurethane.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US431275A US3863603A (en) | 1974-01-07 | 1974-01-07 | Magnetic brush roll having resilient polymeric surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1042655A true CA1042655A (en) | 1978-11-21 |
Family
ID=23711222
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA215,044A Expired CA1042655A (en) | 1974-01-07 | 1974-12-02 | Magnetic brush roll having resilient polymeric surface |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US3863603A (en) |
| JP (1) | JPS5342419B2 (en) |
| CA (1) | CA1042655A (en) |
| FR (1) | FR2257103B1 (en) |
| GB (1) | GB1449393A (en) |
| IT (1) | IT1027650B (en) |
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| JPS4960534A (en) * | 1972-10-11 | 1974-06-12 | ||
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| US3959573A (en) * | 1974-04-26 | 1976-05-25 | Xerox Corporation | Biasable member and method for making |
| JPS50155235A (en) * | 1974-06-04 | 1975-12-15 | ||
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| JPS5634913Y2 (en) * | 1978-03-30 | 1981-08-17 | ||
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| US4564283A (en) * | 1984-06-22 | 1986-01-14 | Xerox Corporation | Blade cleaner apparatus for removing toner from a charge-retentive surface |
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| IL111846A0 (en) * | 1994-12-01 | 1995-03-15 | Indigo Nv | Imaging apparatus and intermediate transfer blanket therefor |
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| US4974027A (en) * | 1989-02-06 | 1990-11-27 | Spectrum Sciences B.V. | Imaging system with compactor and squeegee |
| US4999677A (en) * | 1989-02-06 | 1991-03-12 | Spectrum Sciences B.V. | Imaging system with rigidizer |
| US5047808A (en) * | 1989-02-06 | 1991-09-10 | Spectrum Sciences B.V. | Image transfer apparatus including a compliant transfer member |
| US4985732A (en) * | 1989-03-08 | 1991-01-15 | Spectrum Sciences B.V. | Electrostatic separator |
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| US5202729A (en) * | 1990-10-26 | 1993-04-13 | Canon Kabushiki Kaisha | Developing apparatus having a coated developing roller |
| DE69119612T2 (en) * | 1991-03-26 | 1996-12-12 | Indigo Nv | IMAGE GENERATION SYSTEM WITH AN INTERMEDIATE TRANSFER ELEMENT |
| US6146803A (en) * | 1991-03-28 | 2000-11-14 | Indigo N.V. | Polymer blend liquid toner compositions |
| US6623902B1 (en) * | 1991-03-28 | 2003-09-23 | Hewlett-Packard Indigo B.V. | Liquid toner and method of printing using same |
| USRE37859E1 (en) | 1991-07-09 | 2002-09-24 | Indigo N.V. | Development control system |
| CA2113169C (en) * | 1991-07-09 | 2003-05-27 | Benzion Landa | Latent image development apparatus |
| US5571645A (en) * | 1993-03-12 | 1996-11-05 | Indigo N.V. | Printing with increased color density |
| US5697027A (en) * | 1995-09-20 | 1997-12-09 | Bridgestone Corporation | Developing roller employing an elastic layer between conductive shaft and outer conductive layer and developing apparatus |
| US5851719A (en) * | 1995-12-18 | 1998-12-22 | Fuji Xerox Co., Ltd. | Developing sleeve for electrophotography and process for image formation |
| JP2003533741A (en) | 2000-05-17 | 2003-11-11 | ヒューレット−パッカード・インデイゴ・ビー・ブイ | Fluorescent liquid toner and printing method using the same |
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| JP4467944B2 (en) * | 2002-10-30 | 2010-05-26 | キヤノン株式会社 | Developer carrier and developing device |
| JP4937600B2 (en) | 2006-02-13 | 2012-05-23 | 株式会社リコー | Developing device, process cartridge, and image forming apparatus. |
| DE102007027473A1 (en) | 2007-06-14 | 2008-12-18 | Manroland Ag | Technically produced functional components |
| CN103797422B (en) | 2011-09-09 | 2017-07-18 | 惠普深蓝有限责任公司 | Method and apparatus for concentrating the ink for electrostatic printing processes |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3455276A (en) * | 1967-05-23 | 1969-07-15 | Minnesota Mining & Mfg | Magnetically responsive powder applicator |
| US3543720A (en) * | 1968-02-29 | 1970-12-01 | Eastman Kodak Co | Apparatus for development of electrostatic images |
| US3457900A (en) * | 1968-02-29 | 1969-07-29 | Eastman Kodak Co | Single magnetic brush apparatus for development of electrostatic images |
| US3643629A (en) * | 1969-10-20 | 1972-02-22 | Minnesota Mining & Mfg | Magnetic powder applicator |
| US3641969A (en) * | 1969-12-18 | 1972-02-15 | Plastic Coating Corp | Toner unit for photoelectrostatic reproduction |
| US3823688A (en) * | 1972-01-26 | 1974-07-16 | Xerox Corp | Magnetic brush assembly |
-
1974
- 1974-01-07 US US431275A patent/US3863603A/en not_active Expired - Lifetime
- 1974-11-22 FR FR7441912A patent/FR2257103B1/fr not_active Expired
- 1974-12-02 CA CA215,044A patent/CA1042655A/en not_active Expired
- 1974-12-11 GB GB5365574A patent/GB1449393A/en not_active Expired
- 1974-12-13 IT IT30510/74A patent/IT1027650B/en active
- 1974-12-27 JP JP14913574A patent/JPS5342419B2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1449393A (en) | 1976-09-15 |
| JPS50115040A (en) | 1975-09-09 |
| IT1027650B (en) | 1978-12-20 |
| JPS5342419B2 (en) | 1978-11-11 |
| FR2257103B1 (en) | 1976-10-22 |
| DE2460782A1 (en) | 1975-07-10 |
| US3863603A (en) | 1975-02-04 |
| DE2460782B2 (en) | 1976-07-22 |
| FR2257103A1 (en) | 1975-08-01 |
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