This part is a kind of semiconductor called KRA021.

Function of this product has HIGH SENSITIVITY PHOTO INTERRUPTER.

Manufacturers : Kingbright Corporation

Image and pinout :

Some of the text within the PDF file :

Part Number: KRA021 *Application *Features 1.Copiers,printers and Fax Machines. 2.VCRs and CD players. 3.Various position detection sensor. *Dimensions 1.Compact package. 2.High sensing accuracy(Slit width:0.5mm). 3.Printed wiring board direct mounting type(with a locating pin). 3.Gap between light emitter and detector:5mm. 4.Compliant with European RoHS directives. 5.Housing UL rating:94V-0. 6.RoHS compliant. Note:All units are in millimeters unless otherwise indicated. *Absolute Maximum Ratings (Ta=25°C) Parameter Symbol Rating Unit Forward current[1] IF 30 mA Reverse voltage VR 5 V Input KingbrightPower dissipation Peak Forward Current [2] Collector-emitter voltage Emitter-collector voltage Output Collector current Collector power dissipation Operating temperature Storage [ ... ]

KRA021 PDF Datasheet Download