Sharp Kabushiki Kaisha Corporation

Nippon Telegraph and Telephone Public Corporation

Masahiko Aiba

Isao Fujimoto

Takeshi Kasubuchi

Yoichi Yamamoto

Yuji Sumitomo

Rikuo Takano

Ikuo Umeda

Masaaki Kuranishi

Yoichi Shimazawa

Satoshi Murakami

Toshio Kobayashi

Hideyuki Miyake

Tomoo Makita

Yutaka Ohota

Yuhi Yui

Takasumi Wada

Hirokazu Fujita

Hiroji Iwai

Toshio Urakawa

Yukio Mizuno

Yutaka Ohta

Fumio Siozaki

Yuriko Kamei

Tokio Maezawa

Ken-ichi Morimoto

Koichi Furukawa

Kozo Kimura

Minoru Sakama

Mitsushi Matsunaga

Tokio Awata

Kouichi Moriyama

Naohiro Oku

Sumitaka Arikawa

Yuhkichi Tsuchida

Keniti Morimoto

Shoichi Matsunaga

A capacitive load driving circuit () for charging and discharging a capacitive load () is provided with a voltage divider () for dividing a power supply voltage (VH) into a plurality of different voltages (V&#x2013;V), a plurality of condensers () to which the voltages (V&#x2013;V) are respectively charged as terminal voltages, and a switch () for switching connections between the capacitive load () and the condensers (), the switch () sequentially connecting the condensers () in an ascending order of the terminal voltages so that electrostatic energy is supplied to the capacitive load () when the capacitive load () is charged, the switch () sequentially connecting the condensers () in a descending order of the terminal voltages so that electrostatic energy is collected from the capacitive load () when the capacitive load () is discharged. With this, it is possible to provide a capacitive load drive circuit having a simple circuit configuration and capable of efficiently collecting and reusing energy accumulated in the capacitive load, and a capacitive load driving method.

Capacitive load driving circuit, capacitive load driving method, and apparatus using the same

An ink jet printing apparatus and method for forming images by selectively actuating a multiple number of ink chambers. An amount of energy U0, which is determined by U0&equals;Ui&minus;Ud, is applied to each non-ejecting chamber, wherein Ui is the energy imparted to each ejecting chamber and Ud is the energy that is carried away by a single droplet of ink, when all the nozzles are driven to eject ink at a maximum ejection ratio, with the temperature rise of ink jet head being saturated.

Ink-jet head control method and ink-jet printer

A novel laser printer is disclosed, in which heat generating parts are positively cooled while reducing the noise generated by a blowing mechanism. A rotor of the motor for rotating a scanning mirror of a scanning device is surrounded by a cover. An air flow inlet port and an air flow outlet port are formed on the sides of the cover. The space in the proximity of the air flow inlet port and the air flow outlet port is divided by an air flow separation member. One longitudinal end of the air flow separation member is close to the rotor and the other longitudinal end and the lateral ends thereof are connected to the cover. The air flow separation member partially divides the rotating air flow generated around the rotor in the proximity of the air flow outlet port, and generates the discharge air flow, which in turn is discharged out of the cover. A suction air flow is introduced from the air flow inlet port to the interior of the cover which is now negative in pressure, in the form of the rotating air flow.

Laser printer capable of cooling heat generating parts as well as

A high-voltage power pack includes: a switching circuit for effecting switching control of a low-voltage d.c. signal to generate a low-voltage a.c. signal; a high-voltage transformer for increasing the voltage of the low-voltage a.c. signal outputted from the switching circuit to generate a high-voltage a.c. signal; a combination of a rectifying circuit and a low-pass filter for rectifying and smoothing the high-voltage a.c. signal to generate a high-voltage d.c. signal; resistors dividing the high-voltage d.c. signal obtained from and smoothed through the rectifying circuit and low-pass filter; a feedback circuit for controlling the switching circuit so that the potential at a divided point between the resistors may be kept constant; and an a.c. power source for applying an alternating current to the divided point, the alternating current having a frequency component transmissible through the low-pass filter, whereby an a.c. superimposed voltage made of the high-voltage d.c. signal with an a.c. voltage superimposed is obtained from the output side of the low-pass filter.

High-voltage power pack

It is an object of the invention to provide a LED write apparatus wherein the arrangement step of LED chips is eliminated by constituting the LED head by a single LED chip composed of LEDs and electrical connection of the respective LEDs with driving circuits is carried out with ease. A LED head chip is constituted in such a manner that 2400 LEDs in all whose width a is selected to be narrow, namely about 10 .mu.m are formed on a Si substrate having a smaller width (about 30 mm) than that of a photosensitive drum (length of A4 size: 210 mm) through a GaAs substrate and as well peripheral circuits including a driving circuit such as a transistor are integratedly formed on the Si substrate. The light from the LED head chip is magnified via a lens to form an image on the photosensitive drum.

LED write apparatus and method for making same

A laser beam printer includes a movable mirror which is rotated by a scan mirror motor. Laser light is alternately deflected toward an information reading station and an information writing station by applying the laser light to the movable mirror from a semiconductor laser. The laser light is switched between writing-use light and reading-use light at the time the movable mirror is rotated through a predetermined angle. In the laser beam printer having the semiconductor laser which is used for both writing and reading information, information is written and read out during one rotation of the movable mirror. It is therefore possible to perform a reading operation and a writing operation simultaneously by simply switching the laser light at the predetermined time depending on the rotation angle of the movable mirror.

Reading and writing apparatus with rotating mirror

An image forming apparatus comprising a laser optical system for optical scanning on a photosensitive drum. The laser optical system comprises a polygon mirror having mirror surfaces with an inclination of an angle .theta.. The polygon mirror is rotated with each mirror surface inclined by the angle .theta. to a line normal to the scanning plane, while the incident light beams to the polygon mirror are inclined by an angle 2.theta. to the scanning plane, so as to compensate the inclination of the mirror surfaces of the polygon mirror. In this way, the polygon mirror can be easily manufactured by plastic molding without damaging the mirror surfaces.

Polygon mirror, a scanning apparatus and an image forming apparatus

An image recording apparatus which is capable of recording an image by forming a dot for each pixel includes an interface (14) for receiving dot data having 300 dpi dot density, converting unit (15, 16, 17, 18) connected to the interface for converting the received data into dot data having 600 dpi dot density by replacing a dot of a focus pixel with a plurality of dots having patterns corresponding to dot patterns of areas containing the focus pixel, and a base engine unit (13) connected to the converting unit for forming an image in accordance with the converted dot data.

Image recording apparatus for providing high quality image

A sheet turning device in a sheet transporting path for receiving a sheet transported in a predetermined direction turning the sheet and transporting the sheet in the predetermined direction. A pair of rollers are provided with a belt extending between the rollers for turning the sheet. A switch is provided for stopping the sheet transported onto the lower inner surface of the sheet turning belt. A driving shaft circulates the sheet turning belt to transport the sheet kept on the lower inner surface of the sheet turning belt in a direction orthogonal to the predetermined direction. A pressing member is provided for stopping and pressing the sheet on the upper inner surface of the sheet turning belt, and a sheet transporting roller for transporting the sheet pressed by the pressing member in the predetermined direction.

Sheet turning device

An optical printer of the scanning type includes a light emitting element which is drivable in accordance with printing data for emitting light. The printer also includes an optical system which passes the light through the system to focus the light on a photosensitive member. A mirror is movably interposed between the optical system and the photosensitive member to deflect the beam from the optical system, thereby causing the beam to scan the photosensitive member at a high speed. To realize the scanning process, an operation assembly supports the mirror to pivotally move the mirror so that the mirror's reflecting surfaces faces toward the light emitting element by subjecting the mirror to a simple harmonic motion within a specified range of angles.

Optical printer of scaning type

A controlling apparatus for a laser diode which is used in a laser printer or the like to transmit laser beam light rays. According to the output characteristics of the laser diode, a bias is applied in the current region (from 0 to Ixm) of approximately 0 in radiation output. The control object period (from Ix to Ixm) is divided into many stages to perform the radiation output control so as to effect the high-precision output control without the provision of a more complicated circuit. The central processing unit outputs the control signal into the duty controlling means, so that the output of the laser diode may be automatically held constant in accordance with the predetermined process or the operation arranged in advance.

Controlling apparatus for laser diode

A frequency control device for use in a laser printer which comprises a modulator for modulating an original signal by a modulation signal so that the speed of the printing data of the laser printer is changed to compensate the change of the scanning speed of a light spot projected by a polygon mirror in the laser printer without using a f-.theta. lens.

Frequency converter for use in a laser printer

An ink liquid supply system for an ink jet system printer includes an ink intake needle formed in a body of the ink liquid supply system, and an ink cartridge removably mounted on the body of the ink liquid supply system. The ink cartridge includes an opening covered by a rubber seal through which the ink intake needle is inserted when the ink cartridge is mounted on the body of the ink liquid supply system. An ink liquid absorbing pad is attached to the rubber seal so as to cover the seal rubber. The ink liquid absorbing pad functions to prevent the ink liquid from dripping onto the body of the ink liquid supply system when the ink cartridge containing ink is denounted from the body of the ink liquid supply system.

Ink cartridge in an ink jet system printer

A ripple regulating system is disposed in a liquid supply system for minimizing pressure ripples generated by a pump employed in the liquid supply system. The ripple regulating system includes a pressure chamber of which one wall comprises a bellowphragm. A spring is secured to the bellowphragm to apply a predetermined pressure to the pressure chamber. A detection system is associated with the pressure chamber for detecting a balance pressure variation. When the balance pressure becomes higher than the preselected level, an adjusting system is operated to increase the depression pressure generated by the spring, thereby maintaining the constant flow rate supply.

Ripple regulating system in a liquid supply system

A solenoid drive system includes a driver circuit which functions to gradually increase current flowing through a solenoid coil. The attracting force created by the solenoid is proportional to the current flowing through the solenoid coil. When the attracting force becomes greater than a load including the plunger, the plunger moves toward the operating end. At a time when the plunger reaches the operating end, the current is still in the increasing curve and, therefore, an excess force is minimized. This functions to minimize noises created by the plunger movement.

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Nara, Japan

Masahiko Aiba