摘要:
Developer density measuring apparatus comprising a transparent detection window confronting the interior of a developing device, illumination means for illuminating developer comprising a toner and a carrier accommodated in said developing device, and density determining means for determining developer density by the amount of light reflected from said developer measured through said transparent detection window, and wherein the surface of the transparent detection window on the side confronting the interior of the developing device is roughened.
摘要:
An image formation apparatus for forming a full color image in the four colors of cyan, magenta, yellow and black has a optical ATDC sensor attached in a cyan developing device to control the toner density under optical ATDC. A black developing device has the toner density controlled by AIDC. A standard develop efficiency .eta.STD of the cyan developing device obtained as a result of the AIDC is compared with a develop efficiency .eta. of black toner. The toner supply amount of the black developing device is determined according to the comparison result to supply the toner. Thus, an image formation apparatus is provided that can detect at favorable accuracy the toner density of a developing device incorporating a developer of which the toner density cannot be detected using optical ATDC to supply a required amount of toner.
摘要:
The image forming apparatus is provided with a detecting means for detecting transfer efficiency when transferring a toner image from a photosensitive member to a transfer sheet, and a developing efficiency changing means for changing developing efficiency based on the transfer efficiency detected by the detecting means, and corrects the toner consumption predicted by the predicting means based on the transfer efficiency as detected by the detecting means, so as to determine the amount of toner to be replenished. When the developing efficiency is changed based on the transfer efficiency, toner consumption also changes, and does not match the predicted toner consumption. According to the present invention, toner concentration in a developer can be even more accurately controlled by correcting the predicted toner consumption by the change in transfer efficiency. Detection of transfer efficiency is achieved by a method of indirectly detecting humidity in the apparatus, or a method of measuring the amount of toner transferred to a transfer member.
摘要:
In an electrophotographic image forming apparatus, a correction coefficient corresponding to each density level of toner consumption of a developing device is determined in accordance with a selected tone correction method, and/or the ratio of the emission period to the non-emission period of a light source. A toner consumption calculator multiplies the correction coefficients by the number of pixels of each density level of document image data, and determines the amount of toner consumed by the developing device from the sum total value of the multiplication results determined for each density level. A toner replenishment device resupplies toner to the developing device based on the determined amount of consumed toner. As a result, a constant toner concentration Tc normally can be maintained because toner is resupplied based on the calculated amount of toner consumption.
摘要:
An image forming apparatus, such as an electrophotographic copier, forms a test image on a photosensitive member, under constant image forming conditions, and the amount of toner adhering to the photosensitive member is detected. The detected amount of toner is converted into a developer toner concentration, based on a conversion standard. The toner concentration is used to control the operation of a toner replenishment device. The conversion standard is periodically corrected by forming a test image using a developer having a known toner concentration, detecting the amount of adhered toner, comparing the detected result to a standard value, and selecting one conversion standard table from among a number of different conversion tables.
摘要:
A printer control unit carries out a predetermined calculation based on the amount of adhering toner detected by an AIDC sensor and the surface potential of a photoconductor detected by a V sensor to correct the light emission intensity of a light source to prepare light emission characteristic data for .gamma. correction to obtain an optimal image. A .gamma. correcting unit corrects an image signal output from an image signal processing unit using the calculated light emission characteristic data for .gamma. correction to control the light source to emit light based on the corrected data. More specifically, since the .gamma. correction data is obtained by calculation, optimal .gamma. correction can always be carried out without a memory of a large capacity.
摘要:
Using an image forming apparatus, toner images are respectively formed on photosensitive drums of image forming units set along a transport belt, and the toner images are transferred onto the transport belt or a recording sheet transported on the transport belt to form a color image. The image forming apparatus is composed of a first density detecting sensor for detecting a density of a toner image formed on the recording sheet or the transport belt at the upstream side of each transfer position of at least one image forming unit which is located at the downstream side of a first image forming unit in a transport direction of the transport belt and which is selected as a subject of an image forming condition determination, a second density detecting sensor for detecting a density of the toner image formed on the recording sheet or the transport belt at the downstream side of the transfer position, and an image forming condition determining unit for comparing a detection value given by the first density detecting sensor with a detection value given by the second density detecting sensor and for determining an image forming condition in accordance with the comparison result for an image formation performed by the image forming unit selected as the subject.
摘要:
A digital copying machine develops an electrostatic latent image formed on a photosensitive drum with toner, and transfers the developed image onto a sheet. In forming images on the photosensitive drum successively, three types of test patterns are formed in order in intro-image areas between image forming areas, and AIDC is made. The first test pattern is a low-density pattern, the second test pattern is an intermediate-density pattern, and the third test pattern is a high-density pattern.
摘要:
A detection device used in an image forming apparatus, comprises a light-emitting element which emits light towards a toner pattern formed on an image carrier, a first light-receiving element which detects the light reflected from the toner pattern and a second light-receiving element which detects the light reflected from the toner pattern in a fashion different from the first light-receiving element. The detection device calculates the amount of toner of the toner pattern based on the output values from the first and second light-receiving elements as well as the position of the toner pattern based on the output value from the first light-receiving element.
摘要:
The present invention relates to an image forming apparatus for copiers, printers and the like. In the image forming apparatus, a standard pattern image, the density of which is detected by a sensor for controlling conditions of image forming operations, is formed on a photosensitive member. Density values are sampled at a plurality of sampling points on a standard pattern image by operating the sensor with a timing at which said sensor confronts said standard pattern image, and are mutually compared with each other. If the comparison result indicates that the timing of the sampling operation lags the standard pattern image, the sampling timing is corrected by eliminating the timing lag. The sampling operation of a subsequent sampling cycle is thereby conducted based on a corrected timing.