SU866532A1 - Electrophotographic apparatus - Google Patents

Description

(54) ELECTROPHOTOGRAPHIC APPARATUS

The invention relates to electrography and can be used to produce electrographic copies.

Electrographic devices are known that contain an origin table with axles mounted above it, an optical system for slit scanning of the image with input and output optical slits, an image carrier with an electrification arranged in front of the output optical slit, unit, manifestations with a toner metering unit, image transfer and fixing units j, a carrier cleaning unit, a control signal generating unit electrically connected to a high on voltage and by electrician 20

The disadvantage of these devices is the complexity of the automatic control system, which does not allow to regulate the potential of the cylinder charge when exposing originals of different 25 image densities, and the poor quality of the image during tone printing.

The purpose of the invention is to improve the quality of electrophotographic copying of originals of various image density.

The goal is achieved by introducing a control signal forming unit into the electrophotographic apparatus, which is a photocell made in the form of a plate with a photosensitive coating installed above the original table before the optical slug input and electrically connected to the toner metering unit, while the distance from of the photocell to the entrance optical slit is equal to the distance from the electrization to the INPUT optical slit, and the length of the photocell is not less than the length of the input optical slit.

Claims (2)

Depending on the origins density, the automatic system allows sensing the electrophotographic photosensitive layer with parameters guaranteeing high-quality obtaining of the latent electrostatic image, as well as bringing the concentration of toner in the developer to a value that guarantees the corresponding appearance of the latent electrostatic image. The input device of this cHCTeivbi is a linear photocell mounted in front of the exposure area of the original, originals reception desk. The photocell is a plate with photovoltaic properties, the plate length exceeds the width of the original being exposed. The plate is mounted so that “only the reflected light from the exposed original, illuminated by an additional illuminator, falls on it. When reflected light falls on the photosensitive photocell plate, the resistance of the plate changes in proportion to the intensity of the reflected light, which leads to a change in the amount of current transmitted through it, the value of the current density is an indicator of the original, which through the amplifier enters the electronic controller and then through the high voltage unit to the electrolytic charge device and via the time relay to the dispensing body assembly manifestations. The drawing schematically shows an electrophotographic apparatus. The device has selected components that automatically provide high-quality reproduction of originals: lined photocell 1, illuminators 2, optical system 3, cylinder 4 electrophotographic, amplifier 5 electronic regulator 6, high voltage unit 7 (BVN), time relay 8, electrizer 9, dispenser 10 toner, unit 11 of the appearance. The electrophotographic apparatus operates as follows. The original, passing along the plane of the original supply table, passes the photo element 1. Depending on the density of the original sections, its ohmic resistance varies, and, consequently, the current and passage of the ions through it. The change in current is amplified by amplifier 5 and fed to an electronic controller 6. The amplifier has an inversion. (Reverse) input, i.e. if the density of the original increases, the signal from the photocell decreases, and the signal from the amplifier will still be increased due to the presence of an inversion input. This means that the signal at the output of the amplifier varies in direct proportion to the density of the original, and not to the signal from the photocell. The electronic controller 6 controls the high voltage unit 7, which charges the electrophotographic layer of the cylinder 4 with an electrizer 9. The degree of charging of the electrophotographic layer depends on the density of the original. the higher the density of the original, the greater the charge current of the electrophotographic layer and vice versa. At certain values of filling the original with a tonal image (density), when the concentration of the developed powder to the developing mixture may not be enough to fully reproduce the original with increased density, the time relay 8 is switched on for a certain time and the dispenser 10 is prepared. the concentration of the developing mixture in site 11 of the application is necessary. The passage under the node of the original lighters 2 through the optical system 3 is exposed to the photosensitive surface of the cylinder automatically sensed by the required size, providing a high-quality invisible electrostatic image, which is manifested by the node 11, and the corresponding concentration in the developer. To ensure consistency in the operation of the photocell and the electrophotographic system, the photosensitive photocell plate has a coating with a spectral characteristic similar to the electrophotographic layer. For the synchronous issuance of a control signal to the electri- cator, the photocell is located at a distance from the optical entrance slit equal to the distance from the electrician to the entrance optical slit, thus avoiding the use of electronic delay systems. The tests of the proposed electrophotographic apparatus were made, the photoelectric density of the originals was used, which was a plate coated with amorphous selenium and having limited dimensions. Testing is successful, and after making a plate of the required length with photoelectric properties, the tests will be repeated to clarify and adjust the control system components. The proposed device will find wide application in electrophotographic apparatuses designed for tone: copying. Claim 1. Electrophotographic apparatus containing an origin table with illuminators installed above it, an optical system for slit scanning of the image with input and output. optical slots, image carrier with electrification arranged in technological sequence, installed in front of the output optical slit, development unit with toner metering unit, image transfer and image fixing units, carrier cleaning unit, control signal generation unit electrically connected to a high voltage source , and by an electrician, which is different in tbm, that, in order to improve the quality of copying originals of various image densities, the control signal formation unit L is a solar cell, made in the form plastinsy the photosensitive coating, mounted above the table for the original input to the optical gap and electrically associated with the dispenser the distance from the photocell to the entrance optical gap is equal to the distance from the electrosator to the optical output gap. 2. The device pop. 1, is different from the fact that the length of the photocell is not less than the length of the output optical slit. Sources of information, Q taken into account in the examination 1. U.S. Patent 3,586,908, cell.6 03 G 15/02, 1971.