Ricoh Company, Ltd.

Kyocera Document Solutions Inc.

Shinichiro Yamada

Masanobu Fukushima

Shohtaroh Sohma

Katsuhisa Furuse

Koichi Hagino

Yasuhiro Ishizaka

Toshiya Murota

A multifunction peripheral includes an answerer identifying unit, a character data extracting unit, a correct/incorrect determining unit, a question data extracting unit, a question sheet image data creating unit, and an image formation control unit. The correct/incorrect determining unit determines answers on a question sheet as correct or incorrect based on characters extracted by the character data extracting unit. The question data extracting unit extracts a plurality of questions from question data stored in a storage unit in accordance with the ratio of correct answers determined by the correct/incorrect determining unit, for each of answerers identified by the answerer identifying unit. The question sheet image data creating unit creates image data of the question sheet with the questions, which are extracted from the question data by the question data extracting unit, arranged thereon.

Image forming apparatus

A DC-DC converter includes an error amplifying circuit to output an error signal by amplifying differences between a reference voltage and a feedback voltage for an output voltage generated by switching an output transistor between on and off, a triangular wave generation circuit to generate a triangular wave, a PWM comparison circuit to compares the triangular wave with the error signal and output a duty control signal having a duty ratio based on the comparison, a pulse width control circuit to control a pulse width of the duty control signal output from the PWM comparison circuit, and a drive circuit to drive the output transistor according to a signal output from the pulse width control circuit.

DC-DC converter

A switching power supply circuit for generating an output voltage at an output node based on an input voltage at an input node includes a reference voltage generating circuit configured to generate a reference voltage such that during an initial start-up period of the reference voltage a voltage rise rate of the reference voltage within a first predetermined period from a start point of the initial start-up period and a voltage rise rate thereof within a second predetermined period immediately preceding an end point of the initial start-up period are smaller than a voltage rise rate thereof in a period between the first predetermined period and the second predetermined period, a coil disposed between the input output nodes, and a switch circuit configured to switch on and off to control current through the coil in response to comparison between the reference voltage and a voltage proportional to the output voltage.

Switching power supply circuit

A switching regulator switches according to an input signal and performs PWM control with a PWM pulse signal. The switching regulator includes a pulse width limiting circuit that includes a reference current source, a constant current source, a capacitor, an inverting block including a first switch circuit to supply a constant current to the capacitor and a second switch circuit to discharge a voltage across the capacitor to a ground, a determination circuit to determine whether the voltage across the capacitor becomes a given value or greater, and a limiting circuit to limit a pulse width of the PWM pulse signal. The inverting block further includes either a third switch circuit configured to pass the given constant current or a switching control circuit configured to cause the first and second switch circuits to pass the given constant current regardless of the PWM pulse signal.

Growing community of inventors

Osaka, Japan

Shinichiro Yamada