Sharp Kabushiki Kaisha Corporation

Kenji Sugimura

Masaru Tsuji

Hiroshi Tachiki

Atsuyuki Katoh

Yoshiya Kinoshita

Norihide Momose

Youichi Nakanishi

Shinji Matsuda

An original reading apparatus provided with an original placement portion on which an original is place, and an original size/type detecting portion for detecting a size and/or a type of the original placed on the original placement portion, includes: a display portion that performs color display; and a display control portion that changes a color of a display screen displayed on the display portion based on the size and/or the type of the original detected by the original size/type detecting portion.

Original reading apparatus

An image forming apparatus is provided with a high-voltage substrate, a motor and a DC power source. The high-voltage substrate has a developing positive bias circuit and a developing reverse bias circuit which are connected to each other in parallel, in which the developing positive bias voltage is combined with developing reverse bias voltage to generate developing bias voltage. The high-voltage substrate includes a interruption switch for interrupting a reverse current from the motor to the developing reverse bias circuit in a case where an interlock switch is turned off at the time of emergency stop, in which, when the reverse current is interrupted by the interruption switch, electric power that is accumulated in the capacitor is supplied to the developing positive bias circuit to apply the developing positive bias voltage as the developing bias voltage to the developing roller for a given length of time.

Image forming apparatus

By application of a voltage from a power source, a transfer roller carries out both transfers of (A) a first transfer for transferring a toner image on a photoreceptor to an intermediate transfer medium and (B) a second transfer for transferring overlapped color toner image on the intermediate transfer medium at once onto a recording sheet. A transfer voltage in accordance with, for example, a sheet thickness, as detected by sheet type detection of a sheet type detecting section is applied to the transfer roller in each stage. When the sheet type detecting section detects that the recording sheet is longer than a periphery of a fixing belt, a heater lamp is turned on in advance at any instant between a time when the recording sheet is brought into contact with the fixing roller and a time when the fixing roller completes one rotation, taking into consideration a time required for conduction of heat from the heater lamp to the fixing belt. As a result, it is possible to reduce ozone generated and make the device compact, and desirable transfer characteristics in accordance with a sheet type are obtained, thus realizing uniform fixing of an unfixed toner image onto the recording sheet, from the front end to the rear end.

Image forming apparatus having improved image transfer characteristics

An image forming apparatus which applies a voltage from a power source, to a transfer roller for performing a first transfer for transferring a toner image on a photoreceptor to an intermediate transfer medium, and a second transfer for transferring overlapped color toner image on the intermediate transfer medium to a recording sheet. A transfer voltage based on sheet thickness is detected by a sheet type detecting section and applied to the transfer roller in each transfer stage. When the sheet type detecting section detects that the recording sheet is longer than a periphery of a fixing belt, a heater lamp is turned on between a time when the recording sheet is brought into contact with the fixing roller, and a time when the fixing roller completes one rotation. As a result, it is possible to reduce ozone generated in the image forming apparatus and to make the apparatus compact. Further, with the image forming apparatus, desirable transfer characteristics in accordance with a sheet type are obtained, thus realizing uniform fixing of an unfixed toner image onto the recording sheet.

A printer with a plurality of ink ribbon cassettes is capable of printing characters or designs with a selected one of these ink ribbon cassettes. The printer includes a vertically movable cassette table on which the plurality of ink ribbon cassettes are mounted in a stacked relationship, a stepping motor, and a rotary cam mechanism for moving the cassette table up and down when the stepping motor drives to rotate the rotary cam mechanism. There is further provided a memory for pre-storing the rotational speed data for each rotational angle of the rotary cam mechanism according to a variation pattern of load applied to the stepping motor together with the rotation of the rotary cam mechanism. The rotational speed of the stepping motor is controlled accoding to the rotational speed data corresponding toe ach rotational angle of the rotary cam mechanism read out of the memory.

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Osaka, Japan

Kenji Sugimura