Oki Electric Industry Co., Ltd.

Oki Data Corporation

Takehiko Okubo

Katsuyuki Ito

Shinichi Katakura

Jiro Tanuma

Shigeki Nakajima

Naoji Akutsu

Toshikazu Ito

Kazuhiko Itoh

Toshiro Murano

Koichi Negishi

A sensor detects the leading edge of the print medium. A position counter counts a time length required for the print medium to advance from where the print medium is detected by the sensor to the photosensitive drum. The position counter also counts a time length for the print medium to advance past the photosensitive drum. The distance of the toner image from the leading edge of the print medium is determined on the basis of the image data of print data. A row counter counts the number of dots in a direction in which the print medium is transported and a column counter counts the number of dots in a direction perpendicular to the direction the print medium is transported. The distance between the first line of an image data and the line in which a first dot to be printed in the image data is determined on the basis of the contents of the column counter and the row counter. The controller switches the transferring device from the constant current control mode to the constant voltage control mode immediately before the first line is printed on the print medium, thereby allowing transferring of the toner image in accordance with the distance of the toner image from the leading edge of the print medium.

Electrophotographic printer having transferring device with control mode

A multivoltage power supply which can output a plurality of high voltages in parallel. The voltage values of the respective outputs are feedback to an A/D converter. Each feedback signal is converted to a digital signal and the difference between the digital signal and a corresponding predetermined output voltage is then calculated in the form of a digital value. This digital value is inputted to a corresponding auto-reload timer, whereby a pulse signal having a pulse width corresponding to the digital value is output at a predetermined frequency.

Multivoltage power supply and control method thereof

An electrophotographic printer capable of changing its printing speed includes a change signal generating circuit for generating a speed change signal, a head scan cycle setting circuit for setting a cycle time of a scan line of an LED array head, and a motor speed setting circuit for setting a rotation speed of a photosensitive drum. Since the head scan cycle setting circuit and the motor speed setting circuit are activated in response to the speed change signal outputted from the change signal generating circuit, the operations of the photosensitive drum and the LED array head are synchronized with each other, so that the printer can print a fine image on a recording medium. The printer control unit including those circuits also includes control circuits for controlling a constant current supplied to a transfer roller, and for controlling a temperature of fixing rollers, to avoid unevenness of printing.

Electrophotographic printer and method for controlling the same

In an electrophotographic recording device which includes a number of consumable parts, there is provided a first memory for storing a currently integrated total number of prints, and a number of prints at replacement of each consumable part. A second memory stores a number of lifetime prints, which is a conversion of the life of each part into a number of prints. A processor performs a first calculation to calculate a number of prints for replaced consumable parts after such replacement and a second calculation to calculate a wear rate of the replaced consumable parts from the number of lifetime prints read out from the second memory, and from the number of prints calculated by the first calculation. An indication section indicates the wear rate obtained from the second calculation. The number of prints stored in the first memory for the consumable parts at replacement is written into the current total number of prints.

Electrophotographic recording apparatus indicating a wear rate for

An electrophotographic printer comprises an access cover for opening and closing an upper opening of a cavity in an enclosure, a rotatable head holder supported at one adjacent to the inner surface of the access cover, an optical print head provided on the inner surface of the head holder, and a process cartridge containing a photosensitive drum provided so that it can be inserted and removed through the upper opening. The optical print head may have holes provided at both ends thereof, and the process cartridge may have pins which are engageable with the holes on the optical print head, thereby to facilitate alignment between the optical print head and the photosensitive drum. The optical print head may have a surface electrode, and the enclosure may have a pressure-contact type connector, so that when the head holder is closed, the surface electrode of the optical print head and the pressure-contact type connector of the enclosure are connected to enable supply of electric power and print signals to the optical print head.

Growing community of inventors

Tokyo, Japan

Takehiko Okubo