Rohm Co., Ltd.

Hiroaki Hayashi

Takumi Yamade

Eiji Yokoyama

Teruhisa Sako

Takaya Nagahata

Hiromi Ogata

Hiroshi Fukumoto

Tomofumi Mishima

Tokihiko Kishimoto

Kunio Motoyama

Hideaki Hoki

Koichi Wada

Satoshi Miyajima

Tsutomu Hasegawa

Toshikazu Satake

A motor driving circuit generates pulse driving signals, and controls the ON/OFF state of a switching circuit connected to a coil of a motor which is to be driven, thereby controlling the conduction period of the motor. A driving signal generating circuit generates the driving signals such that they are pulse modulated according to the torque target value for the motor, and outputs the driving signals to the switching circuit. A current detection circuit detects the current flowing through the coil of the motor. A current limiting circuit controls the logical values of the driving signals generated by the driving signal generating circuit such that the current detected by the current detection circuit does not exceed a predetermined current upper limit. The current limiting circuit increases the current upper limit according to the time elapsed in the starting operation of the motor. After the starting operation of the motor, the current upper limit is set to a predetermined fixed value.

Motor driving circuit

A fan motor driving circuit controls an energized state of a fan motor by performing on and off control of a switching circuit connected to a coil of the fan motor of a driving object. A variable reference voltage circuit generates a voltage whose voltage level changes with time by charging or discharging a capacitor at the start of starting up the fan motor. A drive signal combining unit generates drive signals on the basis of the voltage when at least starting up, and performs on and off control of the switching circuit by the drive signals. An initialization circuit initializes the capacitor before starting up with a transition from off to on of a power supply voltage to be supplied to the fan motor driving circuit as a turning point.

Fan motor driving circuit

A drive circuit of a fan motor is provided. In an embodiment of the drive circuit, a first PWM comparator compares a temperature detection voltage with a cyclic voltage, and outputs a first PWM signal. A second PWM comparator compares a minimum frequency setting voltage indicating a minimum frequency of the fan motor, with the cyclic voltage, and outputs a second PWM signal. The drive circuit combines the first PWM signal and the second PWM signal by a logical operation, to drive the fan motor. The drive circuit includes a first logic gate which generates a logical sum of the first PWM signal and the second PWM signal, and a second logic gate which generates a logical product of the first PWM signal and an inverted signal of the second PWM signal. The drive circuit switches drive mode based on the first logic gate and the second logic gate.

Motor drive device and cooling device using the same

A drive signal generation circuit generates drive signals that control ON and OFF states of transistors of a H-bridge circuit, in accordance with a target value of torque. A driver circuit alternatively turns ON and OFF high side transistors, and low side transistors of the H-bridge circuit, based on the drive signals outputted from the drive signal generation circuit. The driver circuit immediately turns OFF the high side transistors, when an instruction is issued to stop a motor, and after a predetermined delay time &#x3c4;d has elapsed, turns OFF the low side transistors.

Motor drive circuit

A heater for fusing toner images onto recording paper is provided. The heater includes a supporting base that has an upper surface and a lower surface. The base has a relatively low thermal conductivity. The heater also includes a heating element formed on the upper surface of the base. A heat conductor is provided on the upper or lower side of the base. The heat conductor has a thermal conductivity greater than the thermal conductivity of the base.

Heater with improved heat conductivity

An image sensor according to the present invention includes a casing ( ), a light source disposed in the casing ( ) for emitting light toward an object (K) to be read, and an image sensor board ( ) provided, on an obverse surface thereof, with a plurality of light receiving elements ( ) for generating image signals upon receiving light reflected by the object (K). The image sensor board ( ) is disposed so that the obverse surface thereof is directed inwardly of the casing ( ). The substrate ( ) is provided with a light shielding layer ( ) for covering the reverse surface of the substrate at least entirely over a portion of the obverse surface where the plurality of light receiving elements ( ) are mounted, so that disturbing external light is prevented from entering inside the casing ( ).

Image sensor substrate and image sensor employing it

A method of making a casing of an image sensor is provided. The method includes the steps of preparing the casing, and applying a static electricity preventive to the casing. The casing is formed with a light passage configured to conduct light emitted from a light source. The static electricity preventive is applied to the inner surfaces of the casing defining the light passage. While the application of the preventive is performed, flashes formed at the light passage are removed.

Casing of image sensor and method of making the same

A thermal printhead ( ) comprises a substrate ( ), an electrode pattern ( ) formed on the substrate, including a common electrode and a plurality of individual electrodes, a heating resister ( )connected to the electrode pattern ( ), and a protective coating ( ) including a plurality of layers ( ) covering the electrode pattern ( ) and the heating resister ( ). The protective coating includes an outermost layer ( ) composed mainly of SiC and an admixture of carbon.

Thermal print head and method of manufacturing thereof

The thermal printhead ( ) includes an insulating substrate ( ), a heating resister ( ) formed on the substrate ( ), a first glass coat layer ( ) formed on the substrate ( ) for covering the heating resister ( ), and a second glass coat layer ( ) formed on the first glass coat layer ( ). The heating resister ( ) has a centerline average roughness not greater than 0.3 &mgr;m. The first glass coat layer ( ) has a centerline average roughness not greater than 0.1 &mgr;m.

Thick-film thermal print head and its manufacturing method

An electrical connection structure includes a circuit board provided at an edge thereof with a plurality of external connection terminals, a flexible flat cable provided at an edge thereof with a plurality of connection terminals in corresponding relationship to the external connection terminals of the circuit board, and a corresponding number of clips. Each of the clips has a first clamping portion open in a first direction for inserting the circuit board, and a second clamping portion open in a second direction opposite to the first direction for inserting the flexible flat cable.

Board-cable connection structure

A thermal printhead includes a head substrate ( ), a heating resistor ( ) provided on the head substrate, a plurality of individual electrodes ( ) connected to the heating resistor, and a common electrode ( ) connected to the heating resistor. The thermal printhead is further provided with a first coating layer ( ) covering the heating resistor, the individual electrodes and the common electrode, and a second coating layer ( ) which is formed on the first coating layer and made of sialon containing a conductive material as an additive. The first coating layer is formed with at least one through-hole ( ) or notch ( &prime;), so that the second coating layer is electrically connected to the common electrode via the through-hole or the notch.

Construction of thermal print head and method of forming protective coating

A thermal printhead (A) includes an insulating substrate (,) having an upper surface (,) and a side surface (,), and a heat retaining glaze layer (,) formed on the substrate (,). A heating resistor (,) is formed on the glaze layer (,). The thermal printhead (A) further includes a common electrode (,) and a plurality of individual electrodes. The common electrode (,) has a plurality of teeth (,) connected to the heating resistor (,), and a connecting portion (,) which connects the teeth (,) with each other. An electrode auxiliary layer (,) is formed on the connecting portion (,). The heating resistor (,) and the electrode auxiliary layer (,) are covered with an overcoat layer (,) which is, in turn, covered with a protective layer (,). The connecting portion (,) of the common electrode (,) directly contacts both the glaze layer (,) and the upper surface (,) of the substrate.

Thermal printhead and method of making the same

A thermal printhead,according to the present invention includes a multiplicity of heating elements,formed in a row on an obverse surface of an elongated substrate,at a portion which is offset widthwise toward one longitudinal side of the substrate, and a protective film,formed on the obverse surface of the substrate,at the widthwise offset portion for covering the heating elements,The protective film,is formed to extend on the obverse surface of the substrate,continuously from the widthwise offset portion onto one longitudinal side surface,of the substrate. A longitudinal edge,of the protective film,directed toward the other longitudinal side of the substrate,is tapered.

A thermal printhead according to the present invention includes a substrate, a plurality of heating elements formed on the substrate, at least one drive IC for driving the heating elements, and a sealing portion for sealing the drive IC. The sealing portion contains a resin material and a granular filler having an average grain size not greater than 10 &mgr;m.

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Kyoto, Japan

Hiroaki Hayashi