Abstract: An apparatus which detects a mass of marking material developed on a test patch recorded on a photoconductive surface. The apparatus includes a densitometer, a capacitor sensor and a controller. The densitometer is spaced from and adjacent to the photoconductive surface. The capacitor sensor is also positioned adjacent to the photoconductive surface and spaced therefrom. In operation, the densitometer generates a first signal proportional to the specular component of the total reflectivity of the material deposited on the test patch developed on the photoconductive surface. The capacitor sensor generates a second signal proportional to the mass of material developed on the test patch recorded on the surface. In response to these signals, the controller generates a first control signal as a function of the first signal received from the densitometer in response to the mass of material deposited on the test patch being less than a preselected mass.

Abstract: A printing machine of the type having a plurality of components for printing a document is disclosed. The printing machine includes an air source and a support member having a component mounted thereon. The support member is coupled to the air source which has output ports so that air flows from the output ports.

Abstract: An apparatus for illuminating a photoconductive surface. The apparatus includes a housing defining a chamber and an open end. An imaging device is placed in the housing chamber. The imager transmits light rays through the open end of the housing to the photoconductive surface. An air pump is coupled to the housing. The air pump maintains an outwardly directed flow of air from the open end of the housing so as to move particles away from the open end. Electrically biased electrodes are located between the imaging device and the photoconductive surface. They attract the particles so as to prevent the particles from contaminating the imaging device.

Abstract: An apparatus in which a rotabably mounted donor roll advances toner to an electrostatic latent image recorded on a photoconductive surface. The donor roll has a plurality of conductive electrodes mounted thereon which rotate in unison therewith. A resistive disk is connected electrically to each of the conductive electrodes. The resistive disk also rotates in unison with the donor roll. An electrically conductive brush is in sliding contact with the resistive member. A voltage source, mounted stationarily, is coupled electrically to the resistive member. The voltage applied to each conductive electrode varies as a function of the distance between the voltage source and that conductive electrode.

Abstract: An imaging member having a substrate with a photoconductive layer coated thereon is anisotropic. The anisotropic substrate is stiff along one axis and flexible along another axis. Reinforcing fibers are aligned in the substrate to achieve the relative stiffness.

Abstract: An apparatus for replenishing toner in a developer unit has a plurality of toner discharge units. A selected discharge unit is energized to dispense toner into the developer unit with the other discharge units being de-energized. After the energized discharge unit is substantially depleted of toner, another toner discharge unit is energized. The depleted toner discharge unit is removed and replaced with a new toner discharge unit.

Abstract: A color electrophotographic printing machine in which latent images having a resolution of at least 1.44 million pixels per square inch are recorded on a photoconductive member. Different color toner powder images are developed in superimposed registration with one another to form a composite multicolor image. The composite multicolor image is transferred from the photoconductive member to a receiving member. Toner particles which have a selected pigmentation and small volume average diameters are used to minimize curl of the receiving member.

Abstract: An apparatus which advances sheets from different stacks of sheets. In one mode of operation, two stacks of sheets are supported side by side. A sheet feeder associated with each stack of sheets advances successive uppermost sheets from the respective stack to a transfer station of a printing machine. Alternatively, a single sheet feeder mounted movably in the sheet feeding apparatus may be employed to advance successive sheets from each of the stack of sheets, in lieu two sheet feeders. In the absence of these stacks of sheets, another oversized stack of sheets may be positioned in the sheet feeder. This oversized stack of sheets extends from a first sheet storing section into a second sheet storing section. When two stacks of sheets are disposed in the sheet feeder, one stack is positioned in the first sheet storing section and the other stack is positioned in the second sheet storing section. In this way, the sheet feeding apparatus has capability of feeding multiple size sheets.

Abstract: A solid area process control for scavengeless development using a transport roll-to-donor roll DC bias as a control parameter in an electrophotographic printing machine is disclosed. The process develops a latent image of a solid area toner patch on a photoconductive belt. Once the patch is developed, the patch is measured with an infrared reflectance type sensor. The measured development mass is compared to a target value stored in the machine memory. A test of the comparison is performed by the process. If the result of the test is less than the target value, the transport roll-to-donor roll bias is increased and the process ends. If the result is more than the target value, the transport roll-to-donor roll bias is decreased and the process ends, otherwise the process stops because the measured development is acceptable. The process is run at predetermined intervals to maintain constant output from the electrophotographic printing machine.

Abstract: A method and apparatus for identifying surface relief features of a substrate processed in a printing machine, and adjusting the machine parameters as a function thereof, before the substrate is processed through the machine. The apparatus includes a light source positioned adjacent to the substrate surface. A light sensing device, in a light receiving relationship with the substrate surface, detects light reflected from the substrate surface. A signal is generated indicative of sensed light intensity with a first magnitude range indicating ridges and a second magnitude range indicating depressions. Control circuitry, electrically connected to the light sensing device, receives the signals of ridges and depressions, and discriminates between them to generate a set of signals indicating surface relief features of the substrate.

Abstract: An apparatus in which sheet basis weight is determined as a function of a change in angular velocity of a roller defining a nip through which the sheet passes. The sheet basis weight is calculated in response to the change in angular velocity of the roll before and after the sheet enters the nip. In an electrophotographic printing machine, the change in angular velocity of the fuser roll or pressure roll may be used to calculate the sheet basis weight.

Abstract: A multicolor electrophotographic printing machine employing a plurality of developer units. Each of the developer units is actuated to develop a selected latent image with the appropriately colored toner particles. The other developer units are de-energized. In the development mode, the electrode wires and the donor roll are electrically biased to suitable voltages. In the non-development mode, the electrode wires have only a DC voltage applied thereon with the AC voltage being turned off. Substantially, simultaneously therewith, the electrical bias on the donor roll is adjusted to prevent further development. In this way, the developer unit does not develop a latent image in the non-operable mode and does not attract toner particles thereto from the latent image.

Abstract: An apparatus in which an advancing copy sheet is disclosed. The apparatus includes a moving imaging member having a toner image thereon. The copy sheet contacts an imaging member to transfer a toner image from the imaging member to the copy sheet. A fusing member fuses the toner image to the copy sheet and advances the copy sheet at an adjustable velocity while the copy sheet receives the toner image from the imaging member. A controller communicates with the imaging member and the fusing member to maintain the velocity of the copy sheet with that of the imaging member. The velocity is maintained at a selected relationship. An imaging member drive moves the imaging member at a first velocity. The imaging member drive includes: a crystal clock that generates a fixed reference signal, a programmable divider which receives the signal and generates a control signal, and a servo motor responsive to the control signal. A fuser drive rotates the fuser roll to advance the sheet at a second velocity.

Abstract: An electrophotographic printing machine in which an electrostatic latent image recorded on a photoconductive member is developed with a liquid developer material. The liquid developer material is advanced by a substantially smooth donor roll from a supply to the latent image at a development zone. The liquid developer material on the donor roll is maintained at a thickness ranging from about 3 microns to about 10 microns.

Abstract: An apparatus which separates and advances successive individual sheets from a stack of sheets. The stack of sheets is supported on a tray which moves in upwardly direction to position the uppermost sheet in engagement with an endless belt. The endless belt moves in a recirculating path to advance successive sheets from the stack. A retard roller engages the endless belt to define a nip for separating any overlapped sheets. Interposed between the retard roller and the tray is a stationary guide member. As the sheet advances toward the nip from the stack, it engages the guide member and is guided toward the nip. A thin, flexible member has one end secured to the guide member. The other end of the flexible member is free and extends into the nip. The flexible member is interposed between the belt and the retard roller with the sheet passing between the belt and the flexible member into the nip.

Abstract: An apparatus in which a donor roll advances toner to an electrostatic latent image recorded on a photoconductive member. A plurality of electrode wires are positioned in the space between the donor roll and the photoconductive member. The electrode wires extend in a transverse direction relative to the longitudinal axis of the donor roll. The electrode wires are electrically biased to detach the toner from the donor roll so as to form a toner cloud in the space between the electrode wires and photoconductive members. Detached toner from the toner cloud develops the latent image. Electrode wires contact a portion of the surface of the donor roll. As the donor roll rotates, friction between the electrode wires and donor roll causes trapped debris to move away from the toner powder cloud region so as to minimize contamination produced streaks on the developed image.

Abstract: A printing machine in which a recording medium has a latent image recorded thereon. A housing stores a supply of liquid developer material therein. The housing is operatively associated with a donor member for substantially uniformly coating liquid developer material thereon. The donor member is spaced from the recording medium. As the donor member moves, it transports the developer material to a development zone wherein the latent image recorded on the recording medium attracts at least the toner thereto to form a developed image thereon. A multicolor image may be formed by repeating this process for different developer materials.

Abstract: An apparatus in which toner fines are recovered from a recirculating liquid transporting toner pellets cut from extruded toner. The recirculating liquid cleans the pellet cutter and forms a mixture of liquid and toner fines. The recovery unit is positioned between the pellet cutter and a station discharging the pellets. In this way, clean liquid flows into the pellet cutter during each cycle. The recovery unit has a housing defining a chamber having two sections. A sloping screen is located in the chamber covering one of the chamber sections. The mixture of toner fines and liquid is dispensed onto the screen. The liquid passes through the screen and is recirculated. Toner fines collect on the screen. A backwash system washes the toner fines from the screen into the other section of the chamber. The mixture of toner fines and liquid is pumped from the other chamber section into a separator. The toner fines are separated from the liquid and re-used in the extruder.

Abstract: An apparatus in which an electrostatic latent image recorded on a photoconductive member is developed with toner. A donor roll, spaced from the photoconductive member, transports toner to a development zone adjacent the photoconductive member. An electrode member is positioned in the development zone between the photoconductive member and the donor roll. The electrode member is electrically biased to detach toner from the donor roll so as to form a toner powder cloud in the space between the electrode member and the photoconductive member. A unitary magnetic roll is located in the housing to transport developer material to a reload zone where toner particles are attracted from magnetic carrier granules to the donor roll. The parameters are selected to optimize reload and suppress strobe lines.

Abstract: An apparatus in which an electrostatic latent image is developed with liquid toner. The apparatus has a liquid extruder that extrudes a thin film of liquid toner which is attracted to the electrostatic latent image forming a liquid image on a photoconductive surface. The extruder is electrically biased to a suitable magnitude and polarity to ensure that the liquid toner is attracted to the latent image. A vacuum is applied on the liquid toner as it is being attracted to the latent image so as to reduce the thickness of the layer coated thereon.