Minolta Camera Kabushiki Kaisha

Kaoru Takebe

Hiroshi Okamoto

Naoki Toyoshi

Kenji Tabuchi

Susumu Tanaka

Tomoaki Yokoyama

Mineyuki Sako

Taisuke Nagao

Shoichi Tsuge

Tetsuya Utsumi

An electrophotographic copying process produces a photocopy having a negative image in order to highlight information in a specified area. An original image is radiated onto a photosensitive medium to form a first image. A solid block is formed in the specified area of the first image. The first image is then transferred to blank paper. The original image is then radiated onto the photosensitive medium again and a portion of the image is erased in order to form a second image. The second image is then transferred to the sheet of paper having the first image. The resulting image formed on the sheet of paper includes a highlighted second image formed in the specified area.

Image highlighting method

By utilizing an electrophotographic image forming process, a reversal image can be obtained in the following manner:

Reversal image forming method

An image editing method utilizing an electrophotographic process, which method includes a first charging step of charging a photosensitive medium; a step of projecting an image onto the charged photosensitive medium to form an electrostatic latent image; a first developing step of developing the electrostatic latent image into a first powder image by the use of a first toner material having the same polarity as the charged polarity; a first transferring step of transferring the powder image onto a copying paper; a second charging step of again charging the photosensitive medium to a polarity the same as that of the charge established during the first charging step; a step of radiating rays of light to the charged photosensitive medium to remove the electrostatic charge at a specificed area of the photosensitive medium; a second developing step of developing the specified area of the photosensitive medium by the use of a second toner material different in color from the first toner material to form a second powder image; and a second transferring step of transferring the second powder image onto said copying paper so as to cover the first powder image which has been transferred onto the copying paper.

Image editing method

An image forming apparatus capable of producing both a normal image and a reversal image, is provided with a photosensitive member, a charger for charging the photosensitive member, an optical system for forming an electrostatic latent image on the photosensitive member, a first developing device for developing the electrostatic latent image using black toner, a second developing device for developing the electrostatic latent image using white toner, a white paper supply cassette for supplying a white paper into a transfer region confronting the photosensitive member, a black paper supply cassette for supplying a black paper into the transfer region, and a control system including a microcomputer for controlling the developing devices and the paper supply cassettes to form a black toner image on the white paper or a white toner image on the black paper.

Image forming apparatus

An image forming apparatus for use in an electrophotographic copying process and an image forming method for the apparatus, which are arranged to reproduce an image portion of an original document by a black developing material on a white paper sheet when an area of the image portion of the original document is below a predetermined level, and also, reproducing a background portion of the image by a white developing material on a black paper sheet when the area of the image portion of the original document is above the predetermined level, and thus, the black developing material or white developing material is selectively used according to percentages of image areas on the original document.

Image forming apparatus and image forming method employed therefor

The disclosure relates to a method, using an electrophotographic system, including a first process of transferring the image of an original document to a copy sheet and a second process of transferring a half-tone solid on a specified region of the image on the copy sheet transferred at the first process. Accordingly, for example, when a copy sheet is white, a black toner is used in the first image forming process, and a white toner is used in the second image forming process, a white half-tone solid of the white toner is superimposed on the black toner image. As a result, the black toner image formed on the specified region looks soft half-tone.

Image forming method

The invention relates to a method of forming monochromatic or dichromatic copy images with use of a developer composed of a high-resistivity magnetic carrier and a nonmagnetic insulating toner which are triboelectrically chargeable. An electrostatic latent image having at least three different levels of potentials is formed and the toner and carrier are adhered respectively onto first and second image portions.

Method of forming monochromatic or dichromatic copy images

The invention disclosed concerns a method of forming dichromatic copy images. An electrostatic latent image having a first image portion and a second image portion is formed. The first image portion is developed by a first magnetic brush developing device using at least a magnetic toner of first color triboelectrically chargeable to a specific polarity. The second image portion is developed by a second magnetic brush developing device using a mixture of a magnetic carrier substantially not triboelectrically chargeable with the magnetic toner and a non-magnetic toner of a second color triboelectrically chargeable to a polarity opposite to that of the magnetic toner by contact with the magnetic carrier.

Method of forming dichromatic copy images

An image forming method which includes following steps:

Image forming method using three component developer

A magnetic brush developing unit for an electrophotographic reproducing apparatus, the brush element being a nonmagnetic sleeve rotating around fixed magnets, together with a first agitator providing both lateral and progressive mixing of depleted developer (with addition of toner, if necessary) as it leaves the magnetic brush via a scraper blade, a second agitator for additional mixing of the freshened developer and for conveying same to a roll with axial channels on its surface. The channels supply the freshened developer to the sleeve to form a new brush for another pass at a photoconductor having the same or another latent image on it. All adjacent rotating members turn in particular directions to assist circulation of developer and to enhance efficiency of agitation.

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Osaka, Japan

Kaoru Takebe