Abstract: An apparatus for facilitating creation of an improved quality reproduction of an original to be copied includes a first sensor for producing a signal in accordance with the density of the background or nonimage are of the original, a second sensor for producing a signal in accordance with the color of its background, and electronic circuit means for generating a bias voltage based on the sensed density and color of the background of the original for application to a developing apparatus.

Abstract: This specification discloses a developer supply device which supplies separately toner and carrier of a two-component developer and in which supply of toner is controlled in accordance with the variation in volume of the developer within a developing device and supply of carrier is controlled in accordance with the variation in density of the toner.

Abstract: A toner concentration control apparatus of the type for allowing developer to pass through a chute, which is capable of detecting stopping of the flow of the developer in the chute, clogging of the chute with the developer, or coating of a viewing window formed in the chute with the developer, and upon occurrence of such abnormalities, minimizing the trouble therefrom in the operation of the copying machine, in which light from a single light source is simultaneously detected by two photosensors, the light striking one of the photosensors directly and the other after being reflected from the developer comprising toner and carrier particles as the developer passes a viewing window in the chute provided for the detection of the toner concentration within the copying machine, and the output of the photosensors is compared with each other and the concentration of toner in the developer can be determined and adjusted by the comparison value.

Abstract: An automatic development control system having a sensor providing a signal representative of developed toner mass on a patch sample on the photoreceptor. The signal is conveyed to a comparator through signal processing circuits for comparing with a reference signal. The signal processing circuits include digital to analog circuitry also capable of providing analog to digital conversion. The reference signal represents an undeveloped photoreceptor signal normalized to accommodate changing photoreceptor, sensor and operating environment characteristics. A dispenser solenoid activates a toner dispenser through an interrupt mechanism in given increments of time depending upon the error signals generated by the comparator.

Abstract: A photoconductive drum (32) is charged, radiated with a light image of an original document (34) and developed to produce a toner image. The density of the toner image is sensed and additional toner fed to a developing unit (37) if the sensed density is below a predetermined value. The sensed toner density is compensated for variations in charge potential, light image intensity, electrostatic image potential, developing bias voltage, power supply voltage and/or sensor output so as to be independent of these variables.

Abstract: A program controlled multiple stream liquid application process in which longitudinal asynchronism between the application of the portions of liquid is reduced by intermittently or continuously detecting the emission of a test stream at each liquid application station, generating, in response to said detection, an electrical signal indicating the time of emission of each test stream with one or more reference times and thereby to generate a correction signal indicative of the extent of longitudinal asynchronism, and modifying the program control in response to the correction signal. A complementary apparatus is also disclosed. In a separate aspect, multiple stream liquid application apparatus includes means coupling the conveyor and the liquid applicator means so that lateral displacement of the conveyor induces a corresponding displacement of the liquid applicator means.

Abstract: An apparatus and method for detecting the concentration of toner in a multi-component developer of an electrophotographic copying machine utilizes a source of illumination for projecting light onto the developer, and a receiving element for measuring the intensity of light of a predetermined wavelength reflected from the developer, the predetermined wavelength being of a value selected to maximize the intensity of reflected light in response to variations in toner concentration substantially independently of the reflection characteristics of the developer. The amount or concentration of toner in the developer is varied--by the addition of suitable amounts of toner--with the measured intensity of the received reflection of light of the predetermined wavelength.

Abstract: A powdered developer (26) comprising carrier and toner particles is caused to flow by gravity downwardly through a passageway (71). A transparent electrode (62) is disposed in the passageway (71). A light source (64) and photosensor (66) are arranged on opposite sides of the electrode (62) for sensing an amount of attracted toner. The electrode (62) is first de-energized and cleaned by aprtially restricting the passageway (71) below the electrode (62) and allowing developer (26) to accumulate in the passageway (71) from the restriction upwardly past the electrode (62) while a restricted amount of developer (26) flows downwardly through the restriction. Then, the restriction is removed and the passageway (71) blocked above the electrode (62), allowing the accumulated developer (26) to flow downwardly past the electrode (62). Then, the passageway (71) is completely unblocked and the electrode (62) energized with an electric potential causing toner to be attracted thereto.

Abstract: In a system for developing electrostatic images on a moving photoconductive support by contact with a brush of two-component developer powder carried on a moving surface, in which the toner content of the powder is controlled in response to optical sensings of the reflectance of the brush at a location just beyond the developing zone, objectionable fluctuations of the toner concentration are avoided by shaping the developer brush to a constant layer thickness, for instance by reducing its thickness to about 0.5 to 0.6 mm, as the brush is being transported from the developing zone so that the sensings of the reflectance will occur at a constant distance from the brush. As an aid for adjusting or checking the operation of the toner control system, a reference surface having the same reflectance as a developer layer of the prescribed thickness and toner concentration is inserted in place of the brush at the location where reflectance is sensed.

Abstract: An electrophotographic apparatus of the two-component, dry developer and reusable photoconductor type, having a developer unit, and replenisher for supplying toner to the developer unit. The replenisher includes a first supply of virgin toner, and a second supply of used toner. A toner feed device operates to simultaneously feed toner to the developer unit from the first and second replenisher supplies. The proportion of toner fed from the first and second supplies is variable; however, such proportion requires that virgin toner must always be fed. Used toner is provided by collecting toner at the apparatus' cleaning station. Toner-low indication is provided for only the first supply, so as to prevent the feeding of only used toner. A toner concentration sensor signals the need to feed the combination of virgin/used toner to the developer unit.

Abstract: A method and apparatus to detect the toner concentration of two component dry developer comprising toner and carrier includes the use of a toner catcher having a conductive member and which is capacitively charged. The developer is applied to the catcher, which traps the toner to determine the toner content.

Abstract: A toner concentration detecting apparatus comprises a rotatable probe having a toner-receiving face, a case housing the probe, means attached to the case for detecting an amount of toner on the toner-receiving face, and a port formed in the case for discharging stray toner particles from the case. The toner-receiving face is put in contact with a magnetic brush of a developer mechanism, separates toner particles from a developer and receives them. The detecting means includes a light-emitting element for applying light to the toner-receiving face and a light-receiving element for receiving the light reflected by the toner-receiving face and converting the light into an electric signal. The stray toner discharging port extends in the direction in which acts centrifugal force generated by the rotation of the probe and is located near the light-emitting and light-receiving elements.

Abstract: A toner concentration control device comprises a toner supply mechanism for supplying a toner to a developing device, a probe for picking up the toner in the developing agent after development is effected and a control mechanism for controlling the toner supply mechanism. The probe has parallel grooves on the outer peripheral surface thereof which constitute a toner pickup surface. An amount of toner picked up is optically detected and the control mechanism controls the toner supply mechanism based on the result of detection. By so doing, an amount of fresh toner corresponding to an amount of toner spent by development is supplied from the toner supply mechanism to a developing agent in the developing device to maintain constant the toner concentration in the developing agent in the developing device.

Abstract: The magnetic brush development apparatus for developing a latent electrostatic image on a photoconductive material by a magnetic brush formed on a development sleeve comprises a hopper whose outlet for supplying one-component type magnetic developer to the development sleeve is positioned in proximity to the surface of the development sleeve, and a developer detecting apparatus comprising a light emitting element and a light receiving element is positioned in proximity to the outlet of the hopper and the surface of the development sleeve. The light emitting element and the light receiving element are positioned so as to hold therebetween a transparent container for allowing the developer to pass therethrough.

Abstract: A device for detecting toner concentration in a developing solution for developing an electrostatic image includes a casing having a small drainage hole formed at a top portion thereof so that a certain amount of a developing solution will always be present in the casing even when a tank containing a major portion of the developing solution used is made empty for some reason. A lamp and a lightsensitive element are mounted in the casing at locations below the drainage hole so that they may remain submerged in the solution within the casing at all times, thereby to prevent toner particles in the solution from adhering to the active surface of the former and hence errors in the detection due to the adhesion of toner particles. Alternatively, a pair of light transmission members in the form of bundles of optical fibers may be submerged in the solution within the casing, instead of the lamp and element, in order to allow the latter to be disposed externally of the casing.