Document size detection device, image reading device, image forming apparatus, and document size detecting method

Patent metadata

Field	Value
Publication number	US-10855866-B2
Application number	US-201916575457-A
Country	US
Kind code	B2
Filing date	Sep 19, 2019
Priority date	Oct 15, 2018
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A document size detection device includes: a light source to irradiate a document with light; an imaging device to receive light reflected at the document; and circuitry to control switch on and off of the light source and movement in a sub-scanning direction of the light source, and determine a size of the document based on image data acquired by the imaging device. The circuitry is to determine a size in a main-scanning direction of the document based on: first image data acquired when the light source is switched off while the light source is at a first reading position; second image data acquired when the light source is switched on while the light source is at the first reading position; and third image data acquired when the light source is switched on while the light source is being moved from the first reading position to a second reading position.

First claim

The invention claimed is:

1. A document size detection device, comprising:
a light source configured to irradiate a document with light;
an imaging device configured to receive light reflected at the document; and
circuitry configured to control a switching on and off of the light source and movement in a sub-scanning direction of the light source, and determine a size in a main scanning direction of the document based on image data acquired by the imaging device,
wherein the circuitry is further configured to determine the size in the main-scanning direction of the document based on:
first image data acquired when the light source is switched off, while the light source is at a first reading position;
second image data acquired when the light source is switched on, while the light source is at the first reading position; and
third image data acquired when the light source is switched on, while the light source is being moved from the first reading position to a second reading position.

2. The document size detection device according to claim 1 , wherein the circuitry is further configured to divide, in the main-scanning direction, an acquisition area where each of the first image data, second image data, and third image data is acquired, into a plurality of divided areas.

3. The document size detection device according to claim 1 , wherein the circuitry is further configured to discretely divide, in the main-scanning direction, an acquisition area where each of the first image data, second image data, and third image data is acquired, into a plurality of divided areas.

4. The document size detection device according to claim 1 , wherein an acquisition time of each of the first image data, second image data, and third image data acquired by the circuitry corresponds to a plurality of cycles of a synchronization signal.

5. The document size detection device according to claim 1 , wherein the circuitry is further configured to acquire the third image data while a movement speed of the light source is accelerated.

6. The document size detection device according to claim 1 , wherein the circuitry is further configured to acquire the third image data successively a plurality of times.

7. The document size detection device according to claim 1 , wherein the circuitry is further configured to acquire the image data a plurality of times at a predetermined interval.

8. The document size detection device according to claim 1 , wherein, when the circuitry acquires a plurality of detection results corresponding to a plurality of reading positions, the circuitry is further configured to determine the size based on a most frequent detection result.

9. The document size detection device according to claim 8 , wherein, when the circuitry acquires A same number of different detection results, the circuitry is further configured to determine the size based on a most frequent detection result from which a detection result corresponding to the first reading position is excluded.

10. An image reading device comprising the document size detection device according to claim 1 , wherein the circuitry is further configured to read an image of a document having the size detected by the document size detection device.

11. An image forming apparatus comprising:
the image reading device according to claim 10 ; and
an image forming device configured to print, on a recording medium, an image read by the image reading device.

12. A document size detecting method, comprising:
controlling switching on and off of a light source that irradiates a document with light; and
controlling movement in a sub-scanning direction of the light source; and
determining a size in a main-scanning direction of the document based on image data acquired by an imaging device that receives light reflected at the document,
wherein the determining step includes
acquiring first image data when the light source is switched off, while the light source is at a first reading position;
acquiring second image data when the light source is switched on, while the light source is at the first reading position;
acquiring third image data when the light source is switched on, while the light source is being moved from the first reading position to a second reading position; and
determining the size in the main-scanning direction of the document based on the acquired first image data, the acquired second image data, and the acquired third image data.

13. The document size detecting method of claim 12 , wherein the step of acquiring the third image data comprises acquiring the third image away from the first reading position.

14. A non-transitory recording medium which, when executed by one or more processors, cause the processors to perform a document size detecting method comprising:
controlling a switching on and off of a light source that irradiates a document with light;
controlling movement in a sub-scanning direction of the light source; and
determining a size in a main-scanning direction of the document based on image data acquired by an imaging device that receives light reflected at the document,
wherein the determining step includes:
acquiring first image data when the light source is switched off, while the light source is at a first reading position;
acquiring second image data when the light source is switched on, while the light source is at the first reading position;
acquiring third image data when the light source is switched on, while the light source is being moved from the first reading position to a second reading position; and
determining the size in the main-scanning direction of the document based on the acquired first image data, the acquired second image data, and the acquired third image data.

Assignees

• Sasa Tomohiro
• Shirado Hiroki
• Oyama Tadaaki
• Ozaki Tatsuya
• Nambara Kohsuke
• Ricoh Co Ltd

Inventors

• Sasa Tomohiro
• Shirado Hiroki
• Oyama Tadaaki
• Ozaki Tatsuya
• Nambara Kohsuke

Classifications

• H04N1/0075

  Detecting a change in reflectivity · CPC title

• H04N1/00737

  using the scanning elements as detectors · CPC title

• H04N1/00708 Primary

  Size or dimensions · CPC title

• H04N1/00755

  Detecting an interruption of light · CPC title