IMAGE READING DEVICE

Abstract

There is provided an image reading device, which comprises an illumination unit configured to diffuse light from light sources in a predetermined scanning direction to illuminate an object with diffused light, a reading unit having photoreceptors aligned in the predetermined scanning direction to receive light reflected from the object, a detection unit configured to detect lighting status of the light sources; and a controller that obtains an image of the object by using a normal one of the light sources as a main light source if at least one of the light sources is in an abnormal state.

Description

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 is a side cross section of an image reading device according to an embodiment.

FIG. 2A illustrates a configuration of a light guide in the image reading device.

FIG. 2B is a circuit diagram for explaining control of LEDs serving as a light source in the image reading device.

FIG. 3 illustrates a control system of the image reading device.

FIG. 4 is a flowchart illustrating a reading process executed by the image reading device to read an image from an original.

FIG. 5 is a flowchart illustrating an LED trouble check process executed under control of the image reading device.

FIG. 6 is an explanatory explanation for explaining reading regions to be applied depending on a state of an image sensor.

FIG. 7A is a conceptual illustration of a configuration of a contact image sensor unit.

FIG. 7B is an explanatory illustration for explaining a drawback of the image reading device shown in FIG. 7.

FIG. 8 is a part of a reading process executed by an image reading device according to a first variation of the embodiment.

FIG. 9 illustrates an example of a screen displayed on a LCD of the image reading device according to the first example to represent a region within which reading of an image can be performed properly.

FIG. 10 illustrates an example of a configuration of the image sensor having more than three reading units.

FIG. 11 is an example of a graph representing white levels and having a drop.

FIG. 12 is a variation of the light guide having light sources at its one end.

Claims

1. An image reading device, comprising: an illumination unit configured to diffuse light from light sources in a predetermined scanning direction to illuminate an object with diffused light;a reading unit having photoreceptors aligned in the predetermined scanning direction to receive light reflected from the object; anda controller that obtains an image of the object by using a normal one of the light sources as a main light source if at least one of the light sources is in an abnormal state.

2. The image reading device according to claim 1, further comprising a detection unit configured to detect lighting status of the light sources, wherein the controller is configured such that, in response to the abnormal state of the at least one light source of the light sources being detected by the detection unit, the controller controls the reading unit so that the reading unit obtains the image of the object on an opposite side with respect to the at least one light source in the abnormal state in the predetermined scanning direction.

3. The image reading device according to claim 1, wherein the controller defines a reading region within which the reading unit obtains the image of the object with reference to a position on the opposite side of the at least one light source in the abnormal state.

4. The image reading device according to claim 1, wherein: the reading unit is configured such that the photoreceptors are divided into a plurality of blocks each of which includes more than one photoreceptor;the controller is able to control the plurality of blocks concurrently; andthe controller operates not to provide a driving signal for one of the plurality of blocks corresponding to a side on which the at least one light source in the abnormal state lies in the predetermined direction.

5. The image reading device according to claim 1, further comprising a notification unit configured to notify a user to place the object on the opposite side of the at least one light source in the abnormal state.

6. The image reading device according to claim 1, wherein the controller turns off the at least one light source in the abnormal state.

7. The image reading device according to claim 1, wherein: the illumination unit includes a light guide which diffuses light from the light sources; andthe light sources are provided at both ends of the light guide.

8. The image reading device according to claim 1, wherein: the illumination unit includes a light guide which diffuses light from the light sources; andthe light sources are provided at one end of the light guide.

9. The image reading device according to claim 1, wherein each of the light sources includes a plurality of light-emitting devices.

10. The image reading device according to claim 9, wherein each of the plurality of light-emitting devices is a light-emitting diode.

11. The image reading device according to claim 9, wherein the plurality of light-emitting devices of each light source are light-emitting diodes respectively corresponding to primary colors of light.

12. The image reading device according to claim 9, wherein the controller uses all the light sources in a case where all the light sources are in a normal state.

13. An image reading device, comprising: an illumination unit configured to diffuse light from light sources in a predetermined scanning direction to illuminate an object with diffused light;a reading unit having photoreceptors aligned in the predetermined scanning direction to receive light reflected from the object;a detection unit configured to detect lighting status of the light sources, anda controller configured such that, in response to the abnormal state of the at least one light source of the light sources being detected by the detection unit, the controller controls the reading unit so that the reading unit obtains the image of the object on an opposite side with respect to the at least one light source in the abnormal state in the predetermined scanning direction.

14. An image reading device, comprising: an illumination unit configured to diffuse light from light sources in a predetermined scanning direction to illuminate an object with diffused light;a reading unit having photoreceptors aligned in the predetermined scanning direction to receive light reflected from the object;a detection unit configured to detect status of the reading unit; anda controller configured such that, in response to an abnormal state in at least a part of the reading unit being detected by the detection unit, the controller controls the reading unit so that the reading unit obtains an image of the object on an opposite side of the at least a part in the abnormal state in the predetermined scanning direction.

15. The image reading device according to claim 14, wherein: the reading unit has a plurality of reading blocks each of which has photoreceptors aligned in the predetermined scanning direction;the detection unit detects status of each block; andthe controller is configured such that in response to an abnormal state of at least one block of the plurality of reading blocks being detected by the detection unit, the controller controls the reading unit so that the reading unit obtains an image of the object on an opposite side of the at least one block in the abnormal state.

16. The image reading device according to claim 14, wherein the detection unit detects the at least a part of the reading unit is in the abnormal state by detecting a drop in output signals generated by the reading unit.

17. The image reading device according to claim 14, further comprising a notification unit configured to notify a user to place the object on the opposite side of the at least a part in the abnormal state.