Image input device and image input method

Abstract

There is provided an image input device in which a carriage mounted with an image sensor and three types of light source is moved in a sub-scanning direction of a document by a motor and the document is read in a line sequential manner. The image input device includes a controller controlling a driving of the motor, an operation of the image sensor, and lighting and extinguishing operations of the light source; and a detecting unit outputting an edge signal to the controller when detecting a movement of the carriage corresponding to one sub-scanning line. The controller is configured to sequentially light and extinguish the three types of light source whenever receiving the edge signal from the detecting unit so as to sequentially read out electric charge stored in the image sensor during the lighting period of the respective light source; and discard the electric charge stored in the image sensor during an intervening period before receiving a subsequent edge signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers refer to like elements.

FIG. 1 is a schematic diagram showing the arrangement of an image input device in accordance with an embodiment of the invention.

FIG. 2 is a diagram for explaining internal signal flows in the image input device in accordance with the present embodiment.

FIG. 3 is a diagram for explaining an operation of a CIS (contact image sensor) module reading out electric charge in accordance with the present embodiment.

FIG. 4 is a diagram for explaining an operation of an image sensor reading out electric charge in accordance with the known art.

Claims

1. An image input device in which a carriage mounted with an image sensor and three types of light source is moved in a sub-scanning direction of a document by a motor and the document is read in a line sequential manner, the image input device comprising: a controller controlling driving of the motor, operation of the image sensor, and lighting and extinguishing operations of the light source; anda detecting unit outputting an edge signal to the controller when detecting a movement of the carriage corresponding to one sub-scanning line,wherein the controller is configured to:sequentially light and extinguish the three types of light source whenever receiving the edge signal from the detecting unit so as to sequentially read out electric charge stored in the image sensor during the lighting period of the respective light source; anddiscard the electric charge stored in the image sensor during an intervening period before receiving a subsequent edge signal.

2. The image input device according to claim 1, wherein the three types of light source are LEDs of R, G, and B colors.

3. The image input device according to claim 1, wherein the detecting unit is an encoder that detects a predetermined rotation of the motor.

4. An image input method performed by an image input device in which a carriage mounted with an image sensor and three types of light source is moved in a sub-scanning direction of a document by a motor and the document is read in a line sequential manner, wherein the image input device is provided with a detecting unit outputting an edge signal to a controller when detecting a movement of the carriage corresponding to one sub-scanning line, andwherein the image input method comprising:sequentially lighting and extinguishing the three types of light source whenever receiving the edge signal from the detecting unit so as to sequentially read out electric charge stored in the image sensor during the lighting period of the respective light source; anddiscarding the electric charge stored in the image sensor during an intervening period between the time of reading out the electric charge stored in the image sensor during the lighting period of the last one of the three types of light source and the time of receiving a subsequent edge signal.