Ricoh Company, Ltd.

Kazuo Murai

Takashi Saitoh

Hiroshi Takahashi

Yutaka Hasegawa

Yukio Sakano

Shinji Yamakawa

Michiyoshi Tachikawa

Hiromi Okubo

Yoshio Kaneko

Takeshi Ukai

Toshiya Hikita

Midori Aida

Tadato Hashiguchi

Shinji Kato

Shigeo Kurotaka

Kenji Hashimoto

Hisao Murayama

Kyoji Omi

Kouji Ishigaki

Hiroyasu Sumida

Haruhiko Fukuda

Nobuo Kasahara

Yasushi Koichi

Yoshiki Yoshida

Kenichirou Asada

Takanori Itoh

Kenichi Mizuma

Kiyoshi Fukushima

Sumio Suzuki

An original image comprises a printed region on which a predetermined printed matter is realized and a background region on which no printed matter is realized. The shape of a peripheral zone in the original image comprises the shape of the background region, which shape exists particularly at the peripheral region of said original image. It is determined whether or not the original image comprises the special document by detecting the peripheral zone. Further, the original image has an outer-frame region, having a predetermined shape at the peripheral region of the original image. The determination is carried out using a result of measuring the width of the outer-frame region. Further, the width of the outer-frame region comprises a width along a direction substantially perpendicular to a direction extending along the outline of the original image.

Original-discrimination system for discriminating special document, and image forming apparatus, image processing apparatus and duplicator using the original-discrimination system

In a case where facsimile communications are executed via a communication line according to a specified communication protocol, in a machine in the receiving side, expanded functional information indicating the receiving form of the machine is stored in an expanded functional information memory, the expanded functional information stored in the expanded functional memory is returned by a control section to a machine in the transmitting side according to a request from the machine in the transmitting side, and then a facsimile message is received in the receiving form according to the expanded functional information notified from the machine in the transmitting side after a response is returned for controlling an output operation of a color printer.

Facsimile machine and facsimile communication system

An original image comprises a printed region on which a predetermined printed matter is realized and a background region on which no printed matter is realized. The shape of a peripheral zone in the original image comprises the shape of the background region, which shape exists particularly at the peripheral region of said original image. It is determined whether or not the original image comprises the special document by detecting the peripheral zone. Further, the original image has an outer-frame region, having a predetermined shape, at the peripheral region of the original image. The determination is carried out using a result of measuring the width of the outer-frame region. Further, the width of the outer-frame region comprises a width along a direction substantially perpendicular to a direction extending along the outline of the original image.

Original-discrimination system for discriminating special document, and

An image density control method applicable to an electrophotographic copier or similar image recorder for controlling the toner concentration of a two-component developer, i.e., a mixture of toner and carrier to maintain the density of a toner image produced by the developer constant. Predetermined calculations are performed on the basis of the output of a photosensor which is responsive to the toner images representative of reference patterns formed on a photoconductive element.

Image density control method for an image recorder

Image forming apparatus which adds identification information to

Image density control method for image recorder

A color image processing apparatus for automatically feeding a plurality of documents one at a time and processing images printed on the documents. The apparatus automatically discriminates an image as to chromatic/achromatic without errors and thereby executes optimal image processing matching the kind of an image without resorting to operator's manipulations.

Color image processing apparatus

A digital color converting apparatus applicable to a color copier and others for converting only a desired color included in a color image into another desired color. One of a plurality of input image signals which has the highest level is identified to determine a color to be rendered by the instantaneous signals and, then, whether the result of the identification and a color specified are coincident is determined. Hence, color conversion is effected only in those regions in which the image is regarded as being of the color specified. For color conversion, the input image signal associated with an original color to be changed is applied to an output terminal which is assigned to an alternative color while, at the same time, the input image signal associated with the alternative color is applied to an output terminal which is assigned to the original color, i.e., signals individually associated with the original and alternative colors are replaced with each other.

Digital color converting apparatus for color image processor

A color image generating apparatus has a memory circuit for memorizing at least a part of an original image in a test print mode operation of the apparatus. An output circuit is used for reading the memorized image from the memory circuit and repeatedly outputting this image, a plurality of times on one display. Image processing circuit for processing the image with a different print condition at each time of repeatedly outputting the image from the output circuitry is used. A plurality of sample images are each printed in a different print condition and displayed on one test sample print paper so that an optimal desired image is selected from the plurality of test sample images.

Color image generating apparatus

A printer structure relies on a laser modulator operating in response to image data cooperates with a rotary deflector for deflecting the modulated laser onto a recording medium with the rotation of the rotary deflector being controlled by a predetermined signal. A synchronizer receives the deflected laser irradiated from the rotary deflector in the vicinity of the recording medium and the synchronizer outputs a signal which defines a timing which the laser modulator uses to begin modulation. At least three memories are used which are each capable of storing the image data corresponding to one line defined by one deflection of the rotary deflector and a memory control device controls the writing of the image data inputted from an exterior of the printer in one memory means after switching the one memory to a write operation in synchronization with the rotary signal defining the one line. Subsequently, the image data which is written in the particular one memory is read after switching the one memory to a read operation and transferring the read image data to the laser modulator.

Printer

Processing used to represent a gradation by changing the number of black pixels and the number of white pixels in a matrix of 8.times.8 pixels. First, edge information sampled from the input data is allocated to corresponding pixel positions of the output data with priority. A residual gradation value is determined by subtracting a value corresponding to the edge information already allocated from the average gradation of the input data, and black pixels and white pixels are alternately allocated to the remaining pixel positions of the output data except for the edge region, in accordance with the ratio of the number of those remaining pixels to the residual gradation value. When the region except for the edge region is divided into a plurality of regions, an average gradation for each of the divided regions is determined and a residual gradation value is distributed to each of the divided regions in accordance with the ratio between the average gradations, followed by allocating black pixels and white pixels to each of the divided regions in accordance with the ration of the distributed residual gradation value to the number of pixels in that region.

Halftone digital image processing device

A recording image density control method for electrophotography comprising the steps of forming at least two latent electrostatic image patterns with different electric potentials on the surface of a photoconductor; developing the latent electrostatic images patterns to toner image patterns by use of toner contained in the developer; detecting data relevant to image density for each developed toner image pattern (such as the image density of each developed toner image pattern, for instance, by a toner image pattern, for instance, by a photosensor), with a different resolution for each image pattern; determining the ratio of the data for one image pattern to the data for the other image pattern by A/D conversion; and controlling at least one recording image density controlling parameter, such as the amount of the toner supplied to a development apparatus, in accordance with the ratio for controlling recording image density, whereby recording image density can be controlled.

Recording image density control method for electrophotography

An image density control method for electrophotography which controls at least one of various image density parameters in response to values detected from different pattern areas. The image density parameters include an amount of charge deposited on a photoconductive element by a charger, bias voltage for development, toner density in a developer, amount of toner supply to a developing unit and transfer potential. At least two pattern areas having different potentials are formed on the surface of the photoconductive element by at least one of various means for forming charge patterns which include controlling the energization of the charger, controlling an illuminating lamp and projecting an image pattern. At each of the pattern areas, at least one of values associated with an image density is detected which include a surface potential of the pattern area before development, toner density of the pattern area after development, a surface potential of the pattern area after development and an image density of an area of a transferred image which corresponds to the pattern area. The value associated with an image density is compared with a predetermined value and matched with specific one of the pattern areas.

Image density control method for electrophotography

An image density control method for an electrophotographic apparatus is disclosed which prepares a white pattern region and a black pattern region on a photoconductive element whose electrostatic latent images are far different from each other in potential. Values relating to image densities individually associated with the two pattern regions are sensed and, based on the sensed values, parameters relating to image processing which effect image density are controlled. When any of the sensed values does not lie in a predetermined range, it is suitably compensated.

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Tokyo, Japan

Kazuo Murai