Abstract: An electrophotographic device includes a control section configured to control operations of a charging unit, an exposure unit, and other units to satisfy a desired condition.

Abstract: A highly accurate sensor for monitoring the color density of various etchants in etchant regeneration systems is disclosed. The sensor comprises a Pyrex or equivalent tubular sensing chamber and a light cell housing surrounding a portion of the chamber. The chamber contains a rodlike extension extending into the interior of the chamber. The housing accommodates a light source, preferably an LED or laser, and a photodetector, optically coupled through an aperture in the housing. Two such sensors are used in a regeneration apparatus attached to an etching machine used for etching copper, iron, stainless steels or other materials. In another embodiment, multiple sensors are used to detect multiple constituents of the etchant depending on the material being etched and the etchant used. A system employing two sets of sensors is particularly applicable to etchants that pass one color of light well when fully regenerated and another color of light well when fully spent.

Abstract: A liquid developing device comprises a storage tank, a concentration sensor, a level sensor, a concentrated-ink supply pump, a carrier supply pump, an ink discharge pump, and a controller. The storage tank stores ink, including toner and carrier, for developing a photoconductor. The concentration sensor measures a concentration of ink to be supplied to the photoconductor. The level sensor measures the amount of ink stored in the storage tank. The concentrated-ink supply pump sends concentrated ink to the storage tank. The carrier supply pump sends carrier to the storage tank. The ink discharge pump discharges excessive ink from the storage tank. Based on measurement value and amount from the concentration tank and the level sensor, the controller controlls the concentrated-ink supply pump, the carrier supply pump, and the ink discharge pump, so that the concentration and amount of ink stored in the storage tank is retained at a predetermined level.

Abstract: The invention relates to a liquid toner and imaging apparatus provided with an imaging surface having a liquid toner image formed thereon on fibrous toner particles and carrier liquid. The fibrous toner particles can be composed of a polymer portion and pigment dispersed therein, where the polymer portion comprises a surface of the fibrous toner particles and is insoluble in the carrier liquid at temperatures below 40° C., so that the polymer portion will not dissolve or solvate in storage. The polymer portion also is solvatable by the carrier liquid only at temperatures above 50° C. The carrier liquid has, as a major component, first liquid hydrocarbon having a first rate of evaporation, and, as a minor component, second liquid hydrocarbon having a second rate of evaporation which, at room temperature, is at least an order of magnitude less than the first rate of evaporation.

Abstract: A toner developability sensor and method sense toner developability of liquid ink in an ink reservoir of a liquid ink image forming system. The toner developability sensor includes a power supply, a first electrode having at least one surface in contact with the liquid ink and connected to the power supply, and a second electrode spaced from the first electrode. When a potential difference is applied between the first and second electrodes, a developed toner layer is formed on the first electrode. A sensor senses at least one characteristic of the developed toner layer formed on the first electrode. The sensor detects characteristics of the developed toner layer that are directly related to the developability of the toner.

Abstract: A wet type electrophotographic image forming apparatus is capable of indicating timing of replacement of filter due to influence of solvent used in the process of image formation whereby to cause degradation of image quality or fatigue of parts and to restrict discharged vapor concentration of collected solvent. The image forming apparatus employing an ink containing a solvent includes a liquefying device for cooling the solvent evaporated during an image forming process and collecting liquefied solvent, an air pump sucking vapor left unliquefied by the liquefying device and maintained in a vapor state, a pressure sensor detecting a suction pressure of the air pump, and alarm device for comparing an absolute value of a pressure data generated by the pressure sensor and indicative of the suction pressure and a predetermined pressure range and generating an alarm when the absolute value of the pressure data is output of the pressure range.

Abstract: An attriter which applies a strong stress to a liquid developer, sufficient for generating the chemically non-equilibrium state therein, is parallel-connected with a developing unit, so that the stress is applied to a part of the liquid developer carried from a storage tank to a developing tank. However, in order to suppress crushing of the toner due to the application of excessive stress, the operation of the attriter is controlled in the following manner. That is, a charge quantity detection unit which detects the toner charge quantity of the liquid developer in the developing tank is provided, and based on the detection result thereof, the attriter is controlled.

Abstract: A concentration sensor 11y and a level sensor 12y measure the toner concentration and the volume of a developing solution in a storage tank 3y. A carrier feed pump 6 and a toner feed pump 7y are driven and controlled in real time based upon values detected by the sensors 11y and 12y during the printing operation, in order to feed a concentrated toner or a liquid carrier into the storage tank 3y to maintain the volume and the toner concentration of the developing solution in the storage tank 3y within predetermined ranges. The concentration and the volume are adjusted in real time during the printing operation which therefore needs not be interrupted for adjusting the developing solution. This makes it possible to continue the printing operation for extended periods of time.

Abstract: A developer circulation system includes a storage tank which stores a developer, a development device, a developer supply passage through which the developer is supplied to the development device from the storage tank, a developer return passage through which the developer is returned to the storage tank from the development device, a circulation pump, and an agitation member which agitates the developer in the storage tank. An outlet of the developer return passage and an opening of the developer supply passage are located in the storage tank, so as to promote a flow of the developer generated by the rotation of the agitation member, at positions furthest from each other along a flow of the developer from the outlet of the developer return passage and the opening of the developer supply passage.

Abstract: An image forming apparatus includes an image processing circuit for, when a determination circuit for determining an image signal determines that the image signal is an image signal that makes a liquid toner film have a predetermined thickness or less, performing predetermined processing for the image signal, an electrostatic latent image forming section for forming an electrostatic latent image on the image carrier by irradiating the image carrier with a light from exposure means on the basis of the image signal subjected to the predetermined processing, a developing unit for developing the image on the image carrier by using the liquid toner in accordance with the electrostatic latent image, and a transfer section for transferring the image on the image carrier onto the recording medium. With this arrangement, a sharp image can be formed by removing low-density areas produced in liquid toner.

Abstract: An ink delivery system and an ink delivery method are disclosed.

Abstract: An imaging system for effecting electrostatic printing of an image, wherein the imaging system includes at least one contact electrostatic printing engine operable in a novel fashion upon a copy substrate, for imaging and development of a latent image representative of the image, and subsequent transfer of the developed image to the copy substrate. The developed image is created by separating and selectively transferring portions of a high solids content secondary toner cake layer in correspondence with the image and non-image regions of the latent image. A toner cake layer delivery apparatus draws from a supply of high solids content liquid developing material to form a primary toner cake layer on a receiving surface of a receiving member. The primary toner cake layer is subject to uniform charging to a first polarity followed by an induced charge of a second, opposing polarity to a selectable depth.

Abstract: The wet type image forming apparatus includes: a columnar body (3) fixed within an ink tank (1); a plurality (n) of reed switches (4) to (6) that are arrayed in upper and lower directions in the columnar body (3) and respond to a magnet; a float (7) which has a magnet and is floated within the ink tank (1) and moved upwardly or downwardly along the columnar body (3) in association with an increase or a decrease of an ink amount; an ON/OFF state detecting circuit (8) for detecting the ON/OFF states of the reed switches (4) to (6); a memory (10) for setting the correspondence relation between a combination of the ON/OFF states of the reed switches (4) to (6) and the ink amounts at n×2 steps and storing it therein; and a remaining amount judging device (9) for judging the ink amounts at the n×2 steps, by referring to the memory 10, in accordance with the ON/OFF information of the reed switches (4) to (6) sent by the ON/OFF state detecting circuit (8).

Abstract: In a wet-type developing unit (300), a plating roller (400) is disposed parallel to a development roller (110) at a predetermined distance. The plating roller (400) is connected to a variable power source (402) controlled by a voltage controller (404). The plating roller (400) is supplied with a voltage from the variable power source (402) and has an electric potential higher than that of the development roller (110) to move charged particle toners included in a liquid developer film adhered on the development roller (110) toward the development roller (110). The plating roller (400) reduces thickness of the liquid developer film and increase a solid component ratio of the liquid developer film. When the solid component ratio is large, pressure given by a squeezed roller (118) can be smaller.

Abstract: The present invention provides a toner concentration measuring apparatus capable of precisely measuring the concentration of toner in a developer and having first and second light guiding devices whose end surfaces project into a duct traversed by developer fluid and a light receiving device for receiving light transmitted from the first light guiding device to the second light guiding device.

Abstract: Disclosed is a method and apparatus for printing an image on a print medium with a liquid developer which comprises a liquid carrier and a toner dispersed in the liquid carrier. The printing method has: forming a toner image probably containing the liquid carrier, from the liquid developer; removing the liquid carrier from the toner image; transferring the toner image to the print medium; projecting light radiation on the toner image to be transferred, to measure the optical reflection from the toner image to be transferred; and estimating transfer suitability of the toner image to be transferred, by means of the measured optical reflection from the toner image to be transferred, for appropriately controlling the extent of the removing of the liquid carrier The printing apparatus has an optical instrument which projects light radiation on the toner image to be transferred and measures the optical reflection from the toner image to be transferred, in order to appropriately control the carrier remover.

Abstract: A developing unit using a developing liquid and an image forming apparatus including the same are disclosed. The developing unit includes a developing roller made up or a core formed of metal or similar conductive material and a roller portion formed of silicone rubber, urethane rubber or similar elastic material. The roller portion has a volume resistivity ranging from 0 &OHgr;·cm to 107 &OHgr;·cm. The developing roller with this configuration reduces irregular development.

Abstract: A method of controlling an ink agitator of a wet-type electrophotography printer. The method includes the steps of checking and determining the extent of the printer non-usage time during the printer initialization operation, selecting the driving time of the ink agitator according to the extent of the non-usage time from the first step, and driving the ink agitator according to the ink agitator driving time selected at the second step. Here, the printer non-usage time determining step determines whether the non-usage time is a first selection time, a second selection time, or a third selection time and sets a first, second and third ink agitator driving time according to the length of the non-usage time. Accordingly, because the ink agitator is driven according to the non-usage time of the printer, it is able to completely dissolve deposition and lumps of ink even when the non-usage time is substantially long.

Abstract: A liquid level detector includes an electrode portion including a substrate, a first electrode plate separated a predetermined distance from the substrate, a hollow second electrode plate extending from the substrate to the first electrode plate and having an opening corresponding to the outer circumferential surface of the first electrode plate, and a liquid level detecting portion which detects the presence of the liquid at the detection position from a change in electrostatic capacity measured by the first and second electrode plates. Thus, the level of liquid stored in the container can be detected from outside of the container in a non-contact manner, simplifying the structure of the apparatus and preventing the generation of an error in measuring the liquid level due to ink adhering to the container.

Abstract: A developer circulation system includes a storage tank which stores a developer, a development device, a developer supply passage through which the developer is supplied to the development device from the storage tank, a developer return passage through which the developer is returned to the storage tank from the development device, a circulation pump, and an agitation member which agitates the developer in the storage tank. An outlet of the developer return passage and an opening of the developer supply passage are located in the storage tank, so as to promote a flow of the developer generated by the rotation of the agitation member, at positions furthest from each other along a flow of the developer from the outlet of the developer return passage and the opening of the developer supply passage.

Abstract: Disclosed is image forming apparatus, including a photoconductor, a charger charging the surface of the photoconductor, a light source exposing the charged surface of the photoconductor to light to form a latent image, a developing unit supplying a liquid developing agent containing a liquid component and a solid component onto the photoconductor so as to convert the latent image into a visible image, a liquid component adjusting unit for adjusting the weight of the liquid component of the liquid developing agent on the surface of the photoconductor to meet the relationship of 0.1≦Ml/Ms≦4.0, where Ms represents the weight of the solid component of the developing agent supplied onto the photoconductor, and Ml represents the weight of the Liquid component of the developing agent, and a transfer unit transferring the visible image onto an image carrier.

Abstract: A liquid electrophotographic developing apparatus capable of preventing image drift and reducing the load in the squeezing process is disclosed. A developing roller faces a photoreceptor belt with a predetermined spacing to supply a liquid developer to the photoreceptor belt while rotating at a peripheral velocity in the opposite direction to that of the photoreceptor belt in a developing region thereon. A peripheral velocity ratio of the peripheral velocity to a moving velocity of the photoreceptor belt is determined so as to maximize a solid component ratio of a developed toner layer on the photoreceptor belt.

Abstract: An image formation apparatus includes a latent image carrier which is rotatable, a developing unit which supplies a liquid developer to the latent image carrier and develops a latent image formed on the latent image carrier, the liquid developer containing solvent and toner particles, a collecting unit which collects solvent vapor of the liquid developer, a separating unit which separates the solvent vapor from air collected by the collecting unit, a sensor which measures a density of solvent vapor in the separating unit, and a control unit which controls a rotational speed of the latent image carrier in accordance with the density of solvent vapor measured by the sensor.

Abstract: A liquid developing device comprises a storage tank, a concentration sensor, a level sensor, a concentrated-ink supply pump, a carrier supply pump, an ink discharge pump, and a controller. The storage tank stores ink, including toner and carrier, for developing a photoconductor. The concentration sensor measures a concentration of ink to be supplied to the photoconductor. The level sensor measures the amount of ink stored in the storage tank. The concentrated-ink supply pump sends concentrated ink to the storage tank. The carrier supply pump sends carrier to the storage tank. The ink discharge pump discharges excessive ink from the storage tank. Based on measurement value and amount from the concentration tank and the level sensor, the controller controlls the concentrated-ink supply pump, the carrier supply pump, and the ink discharge pump, so that the concentration and amount of ink stored in the storage tank is retained at a predetermined level.

Abstract: An apparatus for measuring the concentration of developer in a liquid printer, the apparatus includes a housing, a developer film forming device installed in the housing for forming a developer film, and a sensing device including a light source unit for emitting colored light corresponding to a range of wavelengths for which the light transmissivity is relatively low to a developer film of a selected color developer, and a photodetector installed corresponding to the light source unit and receiving the light emitted by the light source unit and transmitted through the developer film. Thus, a thin developer film is formed and the concentration of developer is measured by emitting light in a range of wavelengths for which the selected color developer has a relatively low light transmissivity to the developer film. The affect by the toner mixed with other color is relatively less and the concentration of developer can be measured close to the actual concentration although the developer is contaminated.

Abstract: A device for measuring the concentration of a developer liquid for a liquid-type printer, including a container having a discharge portion, first and second rotary members rotatably installed in the container with a predetermined space, and a supply portion for supplying the developer liquid containing toner particles and liquid carrier into the space between the first and second rotary members. A concentration detector is provided for detecting the concentration of the developer liquid by emitting light onto the developer liquid flowing along the space between the first and second rotary members, and receiving the light passed through the developer liquid. In the concentration measuring device, the space between the first and second rotary members can be adjusted to be smaller, and the concentration of a developer liquid having a low light transmittance can also be measured.

Abstract: A concentration sensor 11y and a level sensor 12y measure the toner concentration and the volume of a developing solution in a storage tank 3y. A carrier feed pump 6 and a toner feed pump 7y are driven and controlled in real time based upon values detected by the sensors 11y and 12y during the printing operation, in order to feed a concentrated toner or a liquid carrier into the storage tank 3y to maintain the volume and the toner concentration of the developing solution in the storage tank 3y within predetermined ranges. The concentration and the volume are adjusted in real time during the printing operation which therefore needs not be interrupted for adjusting the developing solution. This makes it possible to continue the printing operation for extended periods of time.

Abstract: In response to a print end instruction from a controller, a development controller checks if the ink density is proper. If the ink density is out of proper range, a circulation path switching valve is turned on to continue ink density adjustment processing even after printing ends. The ink circulation path is switched to allow the ink to flow directly to an ink tank. The ink stored in a supply path from the valve to a developing unit and in the developing unit is returned to the ink tank. In this state, the ink density adjustment processing is performed. A transmission type density sensor senses the current density of X %, and sends the density to the development controller. The development controller retrieves proper density range data of N %-M % from a density adjustment table and compares the sensed density with the proper density range data. If X %>M %, L ml of diluted ink solution is supplied by a supply pump. If X %<N %, K ml of ink dye is supplied by the supply pump.

Abstract: The wet type image forming apparatus includes: a columnar body (3) fixed within an ink tank (1); a plurality (n) of reed switches (4) to (6) that are arrayed in upper and lower directions in the columnar body (3) and respond to a magnet; a float (7) which has a magnet and is floated within the ink tank (1) and moved upwardly or downwardly along the columnar body (3) in association with an increase or a decrease of an ink amount; an ON/OFF state detecting circuit (8) for detecting the ON/OFF states of the reed switches (4) to (6); a memory (10) for setting the correspondence relation between a combination of the ON/OFF states of the reed switches (4) to (6) and the ink amounts at n×2 steps and storing it therein; and a remaining amount judging device (9) for judging the ink amounts at the n×2 steps, by referring to the memory 10, in accordance with the ON/OFF information of the reed switches (4) to (6) sent by the ON/OFF state detecting circuit (8).

Abstract: An automatic developing apparatus is provided with a developing tank, a reserve tank, a pump, a piping which connects the reserve tank and the pump and whose one end is disposed above the developing tank, a first electrode provided in the piping, a second electrode provided within the developing tank, and a sensor which is electrically connected to the first electrode and the second electrode.

Abstract: A testing method for a liquid developer which adjusts a narrow gap formed between circumferences of two moving elements, applies different electric potentials to surfaces of the two moving elements to generate an electric field at the narrow gap, and applies the liquid developer to at least one of the two moving elements at a position upstream from the narrow gap in a moving direction of the two moving elements. Further, the method measures one of 1) a thickness, 2) a weight per unit area, and 3) a volume per unit area of liquid developer adhered to the circumferences of the two moving elements at a position downstream from the narrow gap in the moving direction of the moving elements, and calculates a ratio of one of 1) the thicknesses, 2) the weights, and 3) the volumes of the liquid developer between the two moving elements according to a measuring result in the measuring step.

Abstract: A developer liquid squeegee apparatus for a liquid electrophotographic printer includes a wrap-around developer liquid removal arrangement for removing a wrap-around developer liquid. The removal arrangement compensates for malfunction or poor operation of an air nozzle for spraying airtoward the wrap-around developer liquid on both edges of a first squeegee roller usually provided in a development arrangement to avoid a wrap-around problem.

Abstract: An imaging system for effecting electrostatic printing of an image, wherein the imaging system includes at least one contact electrostatic printing engine operable in a novel fashion upon a copy substrate, for imaging and development of a latent image representative of the image, and subsequent transfer of the developed image to the copy substrate. The developed image is created by separating and selectively transferring portions of a high solids content secondary toner cake layer in correspondence with the image and non-image regions of the latent image. A toner cake layer delivery apparatus draws from a supply of high solids content liquid developing material to form a primary toner cake layer on a movable donor member. The primary toner cake layer is subject to uniform charging to a first polarity followed by an induced charge of a second, opposing polarity to a selectable depth.

Abstract: A liquid material supplier capable of effectively preventing a liquid material, such as ink, held on a surface of a liquid material holding member from drying and an image forming apparatus provided with the same. The supplier includes a liquid material holding member for holding a liquid material on a surface thereof. The liquid material holding member is rotatable in a predetermined direction and supplying, during rotation, the liquid material to a member to be supplied at a given supply position. The supplier further includes a supply station for supplying the liquid material to the surface of the liquid material holding member and a regulating member for regulating the liquid material on the liquid material holding member to a specified thickness. The regulating member is disposed at a position downstream of the supply station and upstream of the supply position in the direction of rotation of the liquid material holding member.

Abstract: A liquid electrophotographic imaging apparatus support system using a network contains an upgrade support server including a database for storing information on developer products in order to provide a service supporting upgrade of data to calculate densities with respect to developer products, and an upgrade support engine connected to a network for supporting access to and search of the database; and a liquid electrophotographic imaging apparatus including a communication device for connecting to the upgrade support server through the network, searching the information on the developer products stored in the database by exchanging information with the upgrade support engine, and downloading the density calculating data with respect to a desired developer product.

Abstract: A toner concentration measuring method and apparatus by which the concentration of toner in solvent can be detected accurately with a simple construction without being influenced by a variation of the conductivity caused by a variation of the amount of ions in the solvent. A stepped dc voltage is applied from a high dc voltage generation section between a pair of electrodes placed in solvent, and very weak current which flows in a circuit formed from the pair of electrodes is measured by a current measuring section. The solvent between the pair of electrodes is replaced into an equivalent circuit, and a capacitance of the equivalent circuit is calculated in accordance with a circuit equation to determine the amount of ions in the solvent. Further, in accordance with a function expression wherein the ion amount and a resistance of the equivalent circuit are used as parameters, a toner concentration from which an influence of a variation of the amount of ions in the solvent is eliminated is determined.

Abstract: Conserving a resource in an image-forming device is accomplished by reducing a wasteful or unused portion in a thin layer of liquid toner developer. Based upon the size of an image-carrying medium, the thin layer of the liquid toner developer is variably formed.

Abstract: An image forming apparatus having an improved developer density detecting device for detecting density of a liquid type developer without using an optical sensor. Density of the liquid type developer is detected based upon viscosity of the liquid type developer, which is obtained by sensing pressures, for example, of the liquid type developer sent by a pump and flowing through a developer circulating pipe and applying pressure data obtained by sensing pressures to a predetermined formula. The viscosity can also be obtained by dropping a steel ball, or moving a steel ball, through the liquid type developer and measuring an induced current in a coil based on movement of the steel ball. The viscosity can also be obtained by measuring torque of a device rotating with the liquid type developer.

Abstract: An image forming apparatus having an improved developer density detecting device for detecting density of a liquid type developer without using an optical sensor. Density of the liquid type developer is detected based upon viscosity of the liquid type developer, which is obtained by sensing pressures, for example, of the liquid type developer sent by a pump and flowing through a developer circulating pipe and applying pressure data obtained by sensing pressures to a predetermined formula. The viscosity can also be obtained by dropping a steel ball, or moving a steel ball, through the liquid type developer and measuring properties based on movement of the steel ball. The viscosity can also be obtained by measuring torque of a device rotating with the liquid type developer.

Abstract: A technique for detecting the toner solids concentration of a liquid toner uses electrostatic sensing and avoids reliance on optical transmission paths, which tend to clog and lead to undertoning or overtoning. The toner solids concentration is instead detected by measuring the residual electric potential of a developed area on an image bearing member. The residual electric potential has been discovered to correlate well with the toner solids concentration.

Abstract: A method for detecting the concentration of an ink liquid including charged particulates is disclosed. A first and a second electrodes are immersed in the ink liquid within an ink chamber. The second electrode is cleaned before a voltage pulse having a predetermined pulse width is applied to the first electrode. The voltage pulse causes a current flowing through the second electrode and a discharging current is detected. The concentration of the charged particulates in the ink liquid is detected from a peak value of the discharging current.

Abstract: A method for controlling concentration of a developer in a developing reservoir of a wet printer includes the steps of counting image data output from a system controller to a laser scanning unit to form an electrostatic latent image on a photosensitive medium, calculating the amount of a consumed toner supplied from the developing reservoir to the photosensitive belt according to a value counted in the counting step of formation of the electrostatic latent image, and supplying toner from a toner supplying unit into the developing reservoir to refill the amount of the consumed toner calculated in the calculation step. The developer also includes a liquid carrier element. Thus, the ratio of the toner to liquid carrier element in the developing reservoir may be maintained within a predetermined range, without having an additional apparatus for measuring the concentration of the developer.

Abstract: An apparatus for measuring the concentration of a liquid developer of an image processor includes: a housing; a rotating roller disposed inside the housing, a driving source for rotating the roller; a developer supplier for supplying the developer to the roller such that a developer film can be formed as the roller rotates, and a sensor for sensing an amount of light transmitted through the developer film by directing light to the developer film and receiving the light transmitted through the developer film.

Abstract: An electrophotographic image generation device such as an electrophotographic printer comprises an image bearing belt, a development section, a toner image transfer section, a toner concentration sensor, and an electrical charge control section. A latent image due to variations in electric potential is formed on the image bearing belt by irradiation of photo image light. The development section applies a liquid developing agent on the surface of the image bearing belt and thereby changes the latent image into a visible toner image. The toner image transfer section transfers the toner image on the surface of the image bearing belt to the surface of a sheet and thereby executes printing to the sheet. The toner concentration sensor detects the concentration of toner particles in the liquid developing agent.

Abstract: A wet-type plate-making machine is disclosed in which the amount of a developer in a developing tank and the toner concentration of the developer are maintained constant. In accordance with the detection values of two liquid level detection switches mounted in the developing tank, the developer is supplied from a developer refill pump thereby to maintain a constant amount of developer. The toner concentration of the developer is maintained constant by supplying the toner from a toner refill pump when the detection value of a concentration detection unit of light-transmission type is low, and by supplying the developer from a developer refill pump when the detection value of the concentration detection unit is high. In the case where the developer concentration or the toner concentration fails to change in this control operation, an alarm signal is outputted indicating that the developer bottle or the toner bottle, as the case may be, is empty.

Abstract: Changes in toner developability of toners in a liquid toner system are determined and compensated for by sensing the toner concentration and liquid toner volume in a tank, based on changes in the toner concentration and toner mass in the tank. Based on the foreground areas for a color separation layer corresponding to a particular toner, the developed area for that toner for one or more printed pages can be determined. From the developed area and the consumed mass of toner, a developed mass per unit area (DMA) can be determined. Based on the determined DMA, the sensed toner concentration and a voltage differential, the developability of the toner can be determined. Based on a target DMA, the sensed toner concentration and the determined developability of the toner, a new voltage differential can be determined.

Abstract: A contact electrostatic printing (CEP) apparatus and method provide custom color capabilities. Custom colors can be provided by combining two or more toner layers of different color. Correction of custom color toner patches can also be performed by combining toner layers. Controllable toner applicators apply toner patches in any desired size, shape or density on a support.

Abstract: In order to detect a toner density in a liquid developer accurately while lowering the influence of ions on the liquid developer, the toner density detecting apparatus 11 detects a toner density in a liquid developer obtained by mixing charged toner particles in a carrier solution. The first and second electrodes 12 and 13 are opposed to each other with a liquid developer therebetween and connected to the first DC power source (V.sub.1) thereby to apply the first electrical field to the liquid developer. The toner density detecting apparatus 11 further includes the third and fourth electrodes 14 and 15 opposed to each other in the direction orthogonal approximately to the direction in which the first and second electrodes 12 and 13 are opposed to each other and connected to the second power sources (V.sub.2, V.sub.3, V.sub.4) thereby to apply the second electrical field.

Abstract: A control apparatus for controlling a concentration of a solute having a predetermined optical absorption characteristic is disclosed. A cell holding member has a plurality of cells formed therein, one of which is placed at a predetermined detection position so that the solution flows through that cell. A concentration of the solute is detected based on the intensity of light that has passed through the cell placed at the predetermined detection position. A cell changer replaces the cell with another cell by moving the cell holding member when a detected concentration has not changed as expected.

Abstract: Toning apparatus for toning an electrostatic latent image, having image and background portions at different potentials on an imaging surface. The apparatus comprises an endless toning surface coated with a layer of concentrated toner and engaging the imaging surface at a toning region. The apparatus additionally comprises a source: of voltage connected to the toning surface and electrifying the toning surface to a voltage operative to selectively transfer at feast a portion of the layer to image: portions on the imaging surface. A developed mass per unit area (DMA) controller having an input indicative of the DMA on the imaging surface is operative to adjust the DMA on the toning surface in response to the input.