Oki Data Corporation

Oki Electric Industry Co., Ltd.

Noboru Otaki

Minoru Isobe

Masato Sakai

Yoshitatsu Okiyama

Hisao Ono

Yoshiharu Momiyama

Shinichi Murakami

Makoto Yabuki

Hiroyuki Inoue

Shigeki Nakajima

Kazuyoshi Yoshida

Atsushi Kurabayashi

Masato Nagata

Fumiaki Yoshida

Norio Ebata

Makoto Otake

Katsuyuki Ito

Shinichi Katakura

Matsusaburo Noguchi

Hiroshi Konishi

Koji Ida

Joji Tadokoro

Syuichiro Ogata

Shuichiro Ogata

Syuiti Fujikura

A color image forming apparatus includes a carrier belt which runs along a transport path of a recording medium to transport the recording medium. A number of image-forming sections are aligned in the transport path. Each of the plurality of image-forming sections forms a toner image of a corresponding color included in an image signal. A plurality of transfer units are provided, with each being disposed to oppose a corresponding one of the number of image-forming sections. Each of the number of transfer units transferring the toner image of the corresponding color to the recording medium. A fixing unit is provided that fixes the toner image to the recording medium. A controller is provided that detects a number of colors in the image signal. The controller sets one set of speeds from a plurality of different sets of speeds in accordance with the number of colors. Each set of speeds includes a speed of the carrier belt, a speed at which each of the image-forming sections forms a respective toner image of a corresponding color, and a speed of the fixing unit. The speed of the carrier belt, the speed at which each of the image-forming sections forms a respective toner image of a corresponding color, and the speed of the fixing unit of any one respective set of speeds are substantially equal to each other.

Color image forming apparatus having a controller for setting printing

A medium transporting mechanism is used in a color image forming apparatus and a color image reading apparatus. The medium transporting mechanism includes a medium holding section and a rotary transporting section. The medium holding section holds a print-medium by clamping the leading end of the print-medium. The rotary transporting section supports the medium holding section thereon and rotates so that the medium holding section travels around a platen in such a manner that the print-medium slides on at least a part of the platen and the medium holding section travels in a loop-like path which is shorter than a maximum dimension of the print-medium in a direction of travel of the print-medium. A color image recording section is located to oppose the platen so that a print-medium passes between the color image recording section and the platen. The color image recording section prints images of yellow, magenta, cyan in sequence and in register on the print-medium. A monochrome image recording section such as an electrophotographic printer may be provided in addition to the color image recording apparatus. The electrophotographic printer prints a black image only. When printing a color image, the electrophotographic printer prints a black image at a high speed and the color image recording section prints images of other colors such as yellow, magenta, and cyan at a slow speed, thereby speeding up overall printing speed in color printing operation.

Image forming apparatus

A color image forming apparatus provides the prolonged life of the photosensitive drums, carrier belt, and toner of the respective colors and improves the quality of the printed color image. A carrier belt transports a recording medium placed thereon so that the recording medium passes through a plurality of printing mechanisms which print images of different colors on the recording medium in superposition. Each printing mechanism prints an image of a corresponding color. The printing mechanism is adapted to be moved into its operative position where the photosensitive drum of the printing mechanism is in contact with the carrier belt to print the image on the recording medium, and into its non-operative position where the photosensitive drum of the printing mechanism is not in contact with the carrier belt. A controller receives print data from a host device such as a personal computer and checks each page of the print data to determine whether any one of a predetermined plurality of colors is missing in the page. If a particular color is missing in the print data, then the controller outputs an UP signal to a positioning mechanism for a corresponding printing mechanism. If the color is not missing, then the controller outputs a DOWN signal. The printing mechanism moves a corresponding printing mechanism into the operative position if the UP signal is received from the controller and into its operative position if the DOWN signal is received.

Color image forming apparatus having a printing mechanism selectively

An image recording apparatus includes a rotating photosensitive drum, a developing unit, a neutralizing device, and a transferring device. An electrostatic latent image is formed on a charged surface of the rotating photosensitive drum, the electrostatic latent image being developed by a developing unit and subsequently transferred by a transferring device to a print medium. The neutralizing device neutralizes the charged surface of the photosensitive drum at the point on the surface disposed downstream of the developing unit and upstream of the transferring device with respect to rotation of the photosensitive drum. A controller controls the neutralizing device according to characteristics of the print medium such as size, material, insulation, and transparency. The neutralizing device may be operated in different modes. For example, the neutralizing device may neutralize an entirety of the charged surface of the photosensitive drum only if the print medium is of a predetermined characteristic, i.e., an insulating sheet such as a transparent OHP sheet or may neutralize only selected parts of the charged surface of the photosensitive drum according to a width of the print medium.

Image recording apparatus having a neutralizing device

A copier, scanner, or printer has serial scanning and/or printing heads. A uniform relative motion is maintained in a longitudinal direction between the head(s) and the scanning and/or printing media. The head(s) move cyclically back and forth at an acute angle to the longitudinal direction, so that each scanning element and/or each printing element scans or prints a pixel line perpendicular to the longitudinal direction. The acute angle and the rate of relative uniform motion are preferably adjustable according to the width of the area to be scanned or printed. For color copying, scanning, or printing, the scanning and/or printing elements are grouped according to color, and are aligned so that the same pixel lines are scanned or printed in different colors.

Serial copier, scanner, and printer employing continuous media transport

A toner image fixing device in an electrophotographic image forming apparatus has a heating roller containing a heater and a backup roller, a surface of which is in contact with a surface of the heating roller. A toner image on the paper is fixed by causing the paper to pass through a contacting portion of the heating roller and the backup roller. The toner image fixing device also has a driving device for supplying driving power to the heating roller or the backup roller to rotate both the heating roller and the backup roller, and a controller. The controller controls the driving section in such a way that both the heating roller and the backup roller begin to rotate intermittently immediately after an electric power supply switch of the apparatus is turned on and heat generation from the heater is initiated, and subsequently begin to rotate continuously when the backup roller achieves one revolution by the intermittent rotation. Alternatively, the rotation speed of the heating roller and backup roller is gradually and continuously increased immediately after electric power is initiated and subsequently reach a constant speed.

Toner image fixing device with rotational control of fixing rollers

A recording apparatus according to the invention includes a first recording device arranged in a first path and a second arranged upstream of the first recording device. A second path has a first end and a second end. A first feed-direction-switching device is arranged upstream of the first recording device and the second path, and downstream of the second recording device. The first feed-direction-switching device directs the medium either to the first recording device or into the first end of the second path. A second feed-direction switching device is arranged downstream of the first recording device and directs the leading end of the medium into the second end of the second path when the first and/or second recording device completes recording of the information on the first side of the medium. The medium is then transported face down through the second path back to the first path for recording on the second side thereof. A method of recording includes first, second, and third mode operations. A medium is printed in monochrome and/or in color in the first and/or second mode. The medium is then transported face down through the second path back to the first path for printing operation performed by the first and/or second recording devices.

Image forming apparatus having a plurality of image forming sections

An electrophotographic recording apparatus that removes reverse-charged toner that is charged with a polarity opposite to a polarity of a normal-charged toner. The apparatus includes a carrier belt; a transfer roller for carrying the toner adhering to the surface of the photosensitive body toward the carrier belt; a transfer power supply for applying to the transfer roller a first voltage that causes the normal-charged toner adhering to the surface of the photosensitive body to be transferred to the recording medium on the carrier belt, and a second voltage, of opposite polarity to the first voltage, that causes the reverse-charged toner adhering to the surface of the photosensitive body to be transferred to the carrier belt; and a carrier belt cleaning blade. A control circuit controls an operation of the transfer power supply, whereby the first voltage is applied to the transfer roller during an image-forming stage, and the second voltage is applied to the transfer roller during a reverse-charged toner removing stage. For example, the normal-charged toner may have a negative polarity, the reverse-charged toner may have a positive polarity, the first voltage may be positive, and the second voltage may be negative.

Electrophotographic recording apparatus having reverse-charged toner

A color printer arranges respective printing mechanisms for printing yellow, magenta, cyan, black and rotatably arranges below the respective printing mechanisms a carrier belt attaching a recording medium thereto and moving it. The carrier belt is formed with timing marks, and photointerrupters are provided to read the timing marks. DIP switches are formed for setting positional errors of the respective printing mechanisms. Printing timings of the respective printing mechanisms are controlled on the basis of the read outputs of the timing marks from the photointerrupters and the set values in the DIP switches.

Color printer correctable positional errors in respective printing

A sheet feed mechanism for feeding sheets one at a time, comprising a hopper loaded with a stack of sheets, a feed roller disposed near the outlet of the hopper, and a resilient tongue held in resilient contact with the central section of the feed roller. The central section of the feed roller is provided with an alternate circumferential arrangement of low friction portions and high friction portions. The friction coefficients between the sheet and the low friction portions is smaller than that between the sheet and the tongue, and the friction coefficient between the sheet and the high friction portions is greater than that between the sheet and the tongue.

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Tokyo, Japan

Noboru Otaki