Toshiba Tec Kabushiki Kaisha

Tokyo Electric Co.

Canon Kabushiki Kaisha

Juntaro Oku

Tadao Kamano

Hiroshi Yamaguchi

Shinichiro Fujii

Takashi Kashiwagi

Masaaki Oyaide

Yasuhiro Suzuki

Sakae Shiida

Hitoshi Ushiogi

Akira Sato

Hidenobu Suzuki

Akira Nuita

Tsugio Narushima

Izumi Araki

Hiroaki Watanabe

Kyouichi Shibata

Akira Satou

A color image-forming apparatus including two drums, two scanners for forming latent images on the two drums, four developing devices for developing the latent images on the drums into toner images with four colors, an intermediate transfer belt successively passing the drums so that the toner images are successively transferred onto the belt, a transfer unit for transferring the toner image on the belt onto a recording medium, and a control unit controlling the two scanners to form patterns of first, second, third, and fourth colors and controlling timing at which the two scanners write on the drums such that the patterns approach one another.

Color image-forming apparatus controlling timing of color pattern formation

An ink-jet printer includes a rotary drum , having a dielectric peripheral surface , for rotating at a constant speed, a sheet loader for loading a sheet to the rotary drum , a sheet holding system for causing the sheet to be held on the peripheral surface of the rotary drum , and a print head section for printing an image on the sheet held on the peripheral surface of the rotary drum by jetting ink to the sheet while the rotary drum makes a predetermined number of rotations. Particularly, the sheet holding system includes a charging section and a supplementary charger section . The charging section is charges the peripheral surface of the rotary drum on an upstream side of the loading point where the leading end of the sheet loaded by the sheet loader contacts the peripheral surface of the rotary drum . The supplementary charger section charges the sheet to supplement the electrostatic attraction force attenuated during the rotation of the rotary drum

Ink-jet printer

An image forming method and apparatus uses an image forming unit including an image carrier and a write unit that forms an image on the image carrier. A moving member moves to transfer, at a transfer position, the image formed on the image carrier and a driving unit rotates and drives the image carrier. A control circuit controls rotation driving of the driving unit on the basis of a rotation state of the image carrier obtained during a predetermined time interval centered on the same rotation position of a preceding rotation as that of a current rotation.

Image forming method and apparatus with controlled image carrier rotation driving based on previous rotation state

An ink-jet printer includes a rotary drum,, having a dielectric peripheral surface,for rotating at a constant speed, a sheet loader,for loading a sheet to the rotary drum,, a sheet holding system for causing the sheet to be held on the peripheral surface,of the rotary drum,, and a print head section,for printing an image on the sheet held on the peripheral surface,of the rotary drum,by jetting ink to the sheet while the rotary drum,makes a predetermined number of rotations. Particularly, the sheet holding system includes a charging section,and a supplementary charger section,. The charging section,charges the peripheral surface,of the rotary drum,on an upstream side of the loading point where the leading end of the sheet loaded by the sheet loader,contacts the peripheral surface,of the rotary drum,. The supplementary charger section,charges the sheet to supplement the electrostatic attraction force attenuated during the rotation of the rotary drum

An ink-jet printer includes a rotary drum for rotating at a constant speed and holding a paper sheet on its peripheral surface, a print head having ink-jet nozzles aligned in the axial direction of the rotary drum to perform printing by spitting ink from these ink-jet nozzles on the paper sheet rotating together with the rotary drum, and a sheet feed-in mechanism for feeding a paper sheet from a cassette and a manual feed tray to the rotary drum. Particularly, the sheet feed-in mechanism has a loading roller unit for loading the paper sheet to the rotary drum, a pickup section for picking up a paper sheet from one of the cassette and the manual feed tray to strike the leading end of the paper sheet against the loading roller unit, and a control section for controlling the loading roller unit to feed, to the rotary drum, the paper sheet whose posture has been corrected upon strike by the pickup section. The pickup section has a paper feed path which guides the paper sheet picked up from one of the cassette and the manual feed tray to the loading roller unit via a merging point, and has a bend accepting space located at the merging point for accepting a bend of the paper sheet.

Ink-jet printer controlling application of printing medium to a rotary

A printing medium discharge apparatus used for discharging a printing medium from a rotary drum in an ink jet printer for printing a desired image onto the printing medium by an ink jet while holding the printing medium on the rotary drum, includes a printing medium carry and discharge device and a printing medium press device. The printing medium carry and discharge device carries thereon the printing medium from the rotary drum, on the printing medium an image having been printed, to make a non-image formation surface of the printing medium including no image formation region contact the printing medium carry and discharge device, and discharges the printing medium carried thereon to be moved apart from the rotary drum. The printing medium press device presses an image formation surface including an image formation region of the printing medium carried on the printing medium carry and discharge device, against the printing medium carry and discharge device, thereby to prevent the printing medium from floating up from the printing medium carry and discharge device while the printing medium is discharged by the printing medium carry and discharge device.

Printing medium discharge apparatus used in an ink jet printer

A power supply control apparatus, in which a high voltage generated by a switching transistor is prevented from being deviated from a nominal value, includes an arithmetic operator for controlling a duty ratio of switching operation of the switching transistor in response to a feedback value. The arithmetic operator includes a comparator for comparing a reference value with a digitized monitor voltage corresponding to the high voltage, and an adder for adding a minimum unit to the feedback value when the digitized monitor voltage is smaller than the reference value and for subtracting the minimum unit to the feedback value when the digitized monitor voltage is larger than the reference value. The result of addition from the adder is used for controlling the duty ratio of switching operation of the switching transistor.

High voltage power supply control apparatus

A high-voltage power source control device comprises a pulse generating section for holding duration data and periodically generating a switching pulse of a duration corresponding to the duration data, a monitor circuit for generating a monitor voltage corresponding to an output voltage of a high voltage power source, an A/D converter for outputting monitor voltage data based on a monitor voltage from the monitor circuit, and a processing section for deriving as adjustment data a difference between the monitor voltage data from the A/D converter and the reference voltage data, adding the adjustment data to the duration data, and setting the result of addition into the pulse generating section as new duration data to change the duty ratio of the switching pulse, thereby maintaining the output voltage of the high voltage power source at or near the reference voltage. The processing section in the control device has a shift register for decreasing the adjustment data at a preset rate.

High-voltage power source control device

A laser power control apparatus which comprises an exciting section for supplying a drive current to a laser oscillation device, a laser power controller for generating current designating data which is incremented and decremented in a binary order, first and second digital/analog converters respectively assigned to lower digits and higher digits of the current designating data, for performing digital-to-analog conversion on the lower-digit data and the higher-digit data, a current setting section for setting a level for the drive current in accordance with the sum of output voltages of the first and second digital/analog converters. In the apparatus, the current setting section has circuit constants which cause the ranges of the drive current for sequential two values of the higher-digit data to be overlapped with each other by a predetermined amount, and the laser power controller has a circuit for limiting the range of the lower-digit data to compensate the overlap of the drive current ranges.

Laser power control apparatus

A high voltage power supply controller includes a plurality of high voltage transformers, and causes the high voltage transformers to generate high voltages upon switching operations of corresponding switching transistors, to there by apply the high voltages to loads. The controller includes a plurality of monitor voltage detectors for respectively monitoring changes in high voltages generated in the high voltage transformers, a multiplexer for sequentially selecting monitor voltages from the monitor voltage detectors at predetermined timings so as to supply the selected monitor voltage to a common analog-to-digital converter, an arithmetic operator for comparing a digital value from the analog-to-digital converter with a predetermined reference value and adding a comparison operation result to a feedback value so as to obtain an output value, a plurality of latches for latching arithmetic outputs corresponding to the monitor voltages output from the arithmetic operator and supplying the latched values to the arithmetic operator as the feedback values, a reference counter for counting reference clocks, and an output control circuit for controlling duty ratios for the switching operations of the switching transistors on the basis of a predetermined frequency reference value, the values latched by the latches, and a count value from the reference counter.

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Numazu, Japan

Juntaro Oku