Abstract: In a multi-stage roll magnetic brush type of developing device, at least two opposite direction rotation rolls which rotate in an opposite rotation direction to that of a photosensitive body are arranged adjacently and oppositely to a photosensitive body, and at least one same direction rotation developing roll which rotates in the same rotation direction as that of the photosensitive body is arranged adjacently, oppositely to the photosensitive body and upstream of the opposite direction rotation developing rolls in the rotation direction of the photosensitive body. Thus, the path of carrying the developer by the same direction rotation developing roll and the opposite direction rotation developing rolls can be optimized. In the wide area printing at high speed, an image with stabilized printing quality can be obtained without an increase in the production cost.

Abstract: A cleaning device for a dry electrophotographic device includes a cleaning brush brought into resilient contact with an object to be cleaned such as a photosensitive drum. A cleaning roll rotates while constantly being brought into contact with the cleaning brush and a cleaning blade is pressed against the cleaning roll to clean the cleaning roll. A rotation direction switching mechanism switches the rotation direction of the cleaning brush such that the rotation direction of the cleaning brush when cleaning the object, for example, during the formation of an image, is different from that when the brush is not cleaning the object.

Abstract: An image recording device of an optical beam scanning type comprising at least one variable frequency generating source which can arbitrarily change the recording density in the main-scanning direction and/or the recording density in the sub-scanning direction for recording an image with an arbitrary dimension without information on the original image.

Abstract: A scanning recording type printing method, in which sampled image of tone data is printed by controlling the scanning length and position of a dot which may include a plurality of different colors in the interior of a pixel such that the dots in two adjacent pixels are paired such that no interruptions exist between the dots.

Abstract: A toner of a first color incorporated into a development appartaus for second color is charged to a polarity opposite to a polarity of a charge of an electrostatic latent image for the second color by a frictional action with a toner in the development apparatus for the second color. The toner of the first color incorporated into the second development apparatus is caused to adhere to a charge-non-released region of a drum, whereby accumulation of the first toner in the second color development apparatus is prevented. The first and second toners are electrostatically transferred onto a paper by a bias electric field having a polarity opposite to that of the toner images, whereby at reversal development of the second color, the toner of the first color adhering to the charge-non-released region is prevented from being transferred onto the paper.

Abstract: A recording member (10) consists, for example, of one endless film-like belt that is folded in a recessed shape. A plurality of printing portions (1-4) are disposed in such a manner as to face the outer peripheral surface of the belt. This recording member is developed simultaneously by toners having different colors. The toner image is transferred to recording paper by transfer units that are disposed in such a manner as to face the upper projecting portion of the belt while interposing therebetween the recording paper that moves linearly along the upper part of the printing portions (1-5, 2-5, 3-5, 4-5).

Abstract: In an electrophotographic recording method in which electric charge is uniformly applied to the surface of a photoconductive drum, the drum surface is then exposed to a first information light beam to form a first negative latent image, the first negative latent image is developed with a first two-component developer, the drum surface is further exposed to a second information light beam to form a second negative latent image, and the second negative latent image is developed with a second two-component developer to produce a two-color toner image, the toner content in the second two-component developer is larger than that in the first two-component developer.

Abstract: Disclosed is a second toner developing apparatus for use in a two color electro-photographic recording apparatus in which a photosensitive drum is uniformly charged, subject to a first exposure, developed with a first toner, subject to a second exposure, and then developed with a second toner. The second developing apparatus is provided with a rotary sleeve for performing magnetic brush development and a fixed magnet disposed within the rotary sleeve. The fixed magnet includes a plurality of magnetic poles of the same polarity provided close to each other, so as to temporarily separate the second developer from the surface of the rotary sleeve at the position of these same polarity magnetic poles. An electrostatic attraction electrode attracts the first toner mixed in the thus separated second developer to thereby remove the first toner from the second developer.

Abstract: A laser beam printer comprises a single scanner deflecting a plurality of laser beams for the purpose of scanning, a laser beam position detector detecting the position of one of the deflected laser beams, and a plurality of delay circuits determining the recording starting timing of the plural laser beams in response to the output signal from the laser beam position detector. The surface of a photosensitive drum is scanned with the plural laser beams to sequentially form a plurality of electrostatic latent images corresponding to a plurality of predetermined colors respectively, and the latent images are sequentially developed with a plurality of color toners during one rotation of the photosensitive drum. The color toner images are simultaneously transferred onto a recording sheet to obtain a record printed in plural colors.

Abstract: In a method for electrophotography comprising an electrostatic transfer process, after an electrostatic latent image formed on a surface of a photoconductive and photosensitive member has been developed with toner, the surface of the photoconductive and photosensitive member and a toner image are charged at the same polarity as the electrostatic latent image and thereafter the toner image is electrostatically transferred onto a recording medium to obtain a record.

Abstract: A nonimpact printer in which electric charges are distributed over the surface of an electrophotographic photosensitive drum by a corona charger, the corona charged surface of the drum is exposed to a first information light, the induced latent image is developed by toner of a first color, the corona charged surface of the drum with the developed image of the toner of the first color is again exposed to a second information light, and the secondly induced latent image is developed by toner of a second color, so that a bicolor toner image is formed on the surface of the drum, which is transferred on a printing medium to obtain a print.

Abstract: A facsimile apparatus having a transmitting unit for scanning an image of a text to produce an image information signal and converting the image information signal to a coded information signal in a band compressed transmission system for transmission through a transmission line, and a receiving unit for decoding the coded information signal transmitted through the transmission line to reproduce the image information on a recording medium, the facsimile apparatus includes a memory having a memory capacity of at least one page information of the text for storing the information signals representing the image of the text to be transmitted and received.

Abstract: An electrostatic photographic method for reversal development using a magnetic brush, with the magnetic brush and photoconductive drum being grounded, and with the development being performed using a dry reversal developer comprising 100 parts by weight of a carrier having ferromagnetic properties and 1 to 10 parts by weight of a toner having a volume specific resistance falling within the range between 3.5.times.10.sup.9 and 1.times.10.sup.11 .OMEGA.-cm.

Abstract: A thermomagnetic recording apparatus, for example, facsimile receiver wherein the surface of a magnetic drum which is uniformly coated with a magnetic material is uniformly magnetized, the magnetized surface is locally heated to a temperature of at least a Curie point in accordance with facsimile signals by means of a thermal recording head, to reduce the coercise force and to invert the polarity of the magnetization, thereby forming a magnetic latent image, and the magnetic latent image is developed with magnetic toner.

Abstract: A developer level sensor installed on the sidewall of a developer container in a developing apparatus consists of an oscillator circuit with multiple coils, the mutual inductance of which is adjusted by a moveable electric conductor. The lower limit level of developer sensed may be adjusted by the positioning of a control plate.

Abstract: Apparatus for monitoring the concentration of toner in a mass of developer mix including the toner and carrier particles, having a sampling cylinder inside which the developer mix flows. An accumulating cylinder is disposed over the sampling cylinder. At the upper end part of the accumulating cylinder, a guide plate is disposed by which the developer mix is supplied to the accumulating cylinder. At the lower end part of the accumulating cylinder, a developer mix supplying roll is disposed by which the developer mix at a fixed flow rate is supplied to the upper end opening of the sampling cylinder. On the other hand, at the lower end opening of the sampling cylinder, there is disposed a magnet roll by which the developer mix at a fixed flow rate is discharged from inside the sampling cylinder.

Abstract: Electrophotography which employs a recording medium prepared by providing a photoconductor layer and a transparent electrical insulator layer on a support. In the electrophotography, a latent charge image is formed on the surface of the insulator layer of the recording medium by the steps of uniformly applying charges of one polarity to the recording medium in a dark place, exposing the recording medium to light reflected from an original image while applying charges of the same polarity to the recording medium at the same time, applying charges of opposite polarity to the recording medium in the dark place, and uniformly exposing the entire surface of the insulator layer of the recording medium to light.

Abstract: In an electronic photographing apparatus, the offset phenomenon which tends to occur due to the conveyance of a developed photosensitive paper by a guide roller and which results in the distortion in a reproduced image is prevented by electrically insulating the toner particles fixed on the photosensitive paper from the guide roller.