Abstract: A method of making a physical unclonable function (PUF) having magnetic and non-magnetic particles is disclosed. Measuring both magnetic field and image view makes the PUF difficult to counterfeit. PUF may be incorporated into a user-replaceable supply item for an imaging device. A PUF reader may be incorporated into an imaging device to read the PUF. Other methods are disclosed.

Abstract: A physical unclonable function (PUF) imaged through two faces is disclosed. The PUF is difficult to counterfeit because the view through both faces must be duplicated for a successful counterfeit. PUF may be incorporated into a user-replaceable supply item for an imaging device. A PUF reader may be incorporated into an imaging device to read the PUF. Other systems and methods are disclosed.

Abstract: A physical unclonable function (PUF) located on a supply item for an imaging device is disclosed. The PUF has a toothed rack configured to mate with a gear. During reading operations, the gear turns and translates the PUF linearly under a magnetic sensor. This configuration is inexpensive and robust. Other devices are disclosed.

Abstract: A physical unclonable function formed by an injection molding machine is disclosed. A highly random distribution of magnetic particles is created by magnetizing magnetizable particles before feeding the particles into the injection molding machine due to turbulence within the injection molding machine. Plastic is also fed into the injection molding machine to suspend the particles. Other devices and processes are disclosed.

Abstract: An elongate physical unclonable function (PUF) is disclosed. The PUF has a longitudinal axis and contains a plurality of small magnetic particles. A much larger magnet is positioned on the longitudinal axis to indicate a home position. A low-cost linear translation mechanism may be used to read the PUF by referencing position information to the home position. Other devices are disclosed.

Abstract: A physical unclonable function (PUF) located on a supply item for an imaging device is disclosed. The PUF has a toothed rack configured to mate with a gear. During reading operations, the gear turns and translates the PUF linearly under a magnetic sensor. This configuration is inexpensive and robust. Other devices are disclosed.

Abstract: An outer sleeve of a magnetic roll for a dual component development electrophotographic image forming device according to one example embodiment includes a series of grooves in an outer surface of the outer sleeve. The grooves extend along an axial length of the sleeve and are spaced circumferentially from each other around the outer sleeve. The outer sleeve has a diameter of between 15 mm and 30 mm, inclusive. The grooves are present on the outer surface of the outer sleeve at a groove density of at least 1.91 grooves/mm of the circumference of the outer surface of the outer sleeve and a total indicated runout of the outer sleeve is 0.05 mm or less.

Abstract: A physical unclonable function (PUF) having magnetic and non-magnetic particles is disclosed. Measuring both magnetic field and image view makes the PUF difficult to counterfeit. PUF may be incorporated into a user-replaceable supply item for an imaging device. A PUF reader may be incorporated into an imaging device to read the PUF. Other systems are disclosed.

Abstract: A developer unit according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. A magnetic roll includes a stationary core and a sleeve positioned around the core that is rotatable relative to the core. The stationary core includes at least one permanent magnet having circumferentially spaced magnetic poles. An upper and a lower magnetically permeable metal shunt are positioned at each axial end of the magnetic roll. Each upper shunt and each lower shunt is positioned axially outboard of the core and in close proximity to the outer surface of the sleeve.

Abstract: An outer sleeve of a magnetic roll for a dual component development electrophotographic image forming device according to one example embodiment includes a series of grooves in an outer surface of the outer sleeve. The grooves extend along an axial length of the sleeve and are spaced circumferentially from each other around the outer sleeve. The outer sleeve has a diameter of between 15 mm and 30 mm, inclusive. The grooves are present on the outer surface of the outer sleeve at a groove density of at least 1.91 grooves/mm of the circumference of the outer surface of the outer sleeve and a total indicated runout of the outer sleeve is 0.05 mm or less.

Abstract: A magnetic roll for transporting a dual component developer mix according to one embodiment includes a core having at least one permanent magnet that has a plurality of circumferentially spaced magnetic poles generating a magnetic field. A cylindrical sleeve is positioned around the core. The sleeve is rotatable relative to the core about a rotational axis in an operative rotational direction. At portions of the magnetic roll positioned axially inward from axial ends of the core, a magnitude of a total magnetic field strength of the magnetic field decreases by 1.5 mT/degree or less in the operative rotational direction at a radius of 0.5 mm beyond an outer circumferential surface of the sleeve throughout an area of ±15 degrees from an angular position of the magnetic roll at which a tangential component of the magnetic field is equal to zero at a release pole of the plurality of magnetic poles.

Abstract: A developer unit according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. A magnetic roll includes a stationary core and a sleeve positioned around the core that is rotatable relative to the core. The stationary core includes at least one permanent magnet having circumferentially spaced magnetic poles. An upper and a lower magnetically permeable metal shunt are positioned at each axial end of the magnetic roll. Each upper shunt and each lower shunt is positioned axially outboard of the core and in close proximity to the outer surface of the sleeve.

Abstract: A developer unit for a dual component development electrophotographic image forming device includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. An axial sealing rib projects from an inner side of the housing toward the outer surface of a sleeve of a magnetic roll. The axial sealing rib extends along an axial length of the sleeve. A distal end of the axial sealing rib is positioned in close proximity to and spaced from the outer surface of the sleeve. The axial sealing rib is positioned to impede the flow of developer mix in the reservoir in a direction counter to an operative rotational direction of the sleeve.

Abstract: A developer unit for a dual component development electrophotographic image forming device according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. An auger is positioned to convey developer mix in the reservoir toward the outer surface of a magnetic roll on a front of the housing. A ledge on an inner surface of the housing extends axially with respect to the magnetic roll along a front of the reservoir. The ledge is positioned upstream from a trim bar and downstream from a pickup pole of the magnetic roll with respect to the operative rotational direction of the magnetic roll. The ledge has a concave curved inner surface that is open to the reservoir and extends from near the trim bar to near a front side of the auger.

Abstract: A method and apparatus for retracting a magnetic brush in an imaging device. The apparatus includes a housing containing carrier beads and toner particles; a magnetic structure at least partly disposed within the housing and generating at least one magnetic field; and an endless sleeve disposed around and rotatable about the magnetic structure, at least a portion of the sleeve extending from the housing. During toner development, the magnetic structure is in a first position for developing a magnetic brush of the carrier beads and toner particles along the portion of the sleeve extending from the housing which forms a developer nip with a photoconductor, and during a period of time when toner development is not to be performed, the magnetic structure is in a second position for retracting the magnetic brush by causing the carrier beads to be positioned against the portion of the endless sleeve extending from the housing forming the developer nip.

Abstract: A developer unit according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. A magnetic roll includes a stationary core and a sleeve positioned around the core that is rotatable relative to the core. The stationary core includes at least one permanent magnet having circumferentially spaced magnetic poles. An upper and a lower magnetically permeable metal shunt are positioned at each axial end of the magnetic roll. Each upper shunt and each lower shunt is positioned axially outboard of the core and in close proximity to the outer surface of the sleeve. A combination of the upper shunt and the lower shunt at each axial end of the magnetic roll surrounds greater than 180 degrees of the outer surface of the sleeve.

Abstract: A developer unit according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. A magnetic roll includes a stationary core and a sleeve positioned around the core that is rotatable relative to the core. The stationary core includes at least one permanent magnet having circumferentially spaced magnetic poles. At least one external shunt is composed of a magnetically permeable metal and is positioned at each axial end of the magnetic roll axially outboard of the core and in close proximity to the outer surface of the sleeve along a first circumferential portion of the core. At least one internal shunt is positioned at each axial end of the core inside of the sleeve. Each internal shunt has a shunt portion composed of a magnetically permeable metal and positioned along a second circumferential portion of the core.

Abstract: A method and apparatus for retracting a magnetic brush in an imaging device. The apparatus includes a housing containing carrier beads and toner particles; a magnetic structure at least partly disposed within the housing and generating at least one magnetic field; and an endless sleeve disposed around and rotatable about the magnetic structure, at least a portion of the sleeve extending from the housing. During toner development, the magnetic structure is in a first position for developing a magnetic brush of the carrier beads and toner particles along the portion of the sleeve extending from the housing which forms a developer nip with a photoconductor, and during a period of time when toner development is not to be performed, the magnetic structure is in a second position for retracting the magnetic to brush by causing the carrier beads to be positioned against the portion of the endless sleeve extending from the housing forming the developer nip.

Abstract: A toner formulation is disclosed comprising a binder and an IR absorbing black pigment at a concentration of 0.25-2.0% by weight, including one or more infrared transmissive pigments, wherein the infrared transmissive pigments are configured to provide a black color. Such toner formulation may provide a response to a toner patch sensor to indicate a mass per unit area of 0.1-1.5 mg/cm2 or a reflectance relative to a substrate to define a reflectance ratio that varies relative to L* values for the toner over the range L*=0-50 or a bulk reflectivity of greater than 6.0% for a portion of the wavelength range of 850-2000 nanometers.

Abstract: A black toner formulation includes at least one non-black colorant selected from the group consisting of dyes, pigments, and combinations thereof. The black toner formulation has a total pigment loading of about 2 percent to less than or equal to about 9.5 percent by weight of total weight of the black toner formulation.