# US 2018/0302530 A1 · Image reading device, pressure plate opening/closing detection method, and image forming apparatus

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- Number: US 2018/0302530 A1
- Document ID: US20180302530A1
- Status: Published application
- Kind: A1
- Application number: 15/939,375
- Filed: 2018-03-29
- Published: 2018-10-18
- Earliest claimed: 2017-04-18
- Assignees: Ricoh Company, Ltd.
- Inventors: Tetsuo Inui; Susumu Miyazaki
- Web page: https://patentgrep.com/patent/US20180302530A1

## CPC

- H04N 1/401: Compensating positionally unequal response of the pick-up or reproducing head (H04N1/403 takes precedence)
- G03G 15/60: {Apparatus which relate to the handling of originals (for photographic purposes in general G03B)}
- H04N 1/00814: {according to a detected condition or state of the reading apparatus, e.g. temperature}
- H04N 1/40056: {Circuits for driving or energising particular reading heads or original illumination means (H04N1/401, H04N1/407 take precedence)}
- G03G 15/607: {for detecting size, presence or position of original}
- G03G 2215/00189: original moving
- G03G 2215/0129: horizontal medium transport path at the secondary transfer
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image reading device including a contact glass; a reading unit; a pressure plate; a pressure-plate opening/closing sensor, and circuitry. The circuitry determines a presence or absence of external light input to a space between the pressure plate and the surface of the contact glass based on image data obtained by the reading unit when the light source is turned off; compares read data according to light emitted from the light source and received by the image sensor when the pressure plate is closed, with read data of a reference value obtained when the pressure plate is completely closed, to obtain a difference and determine a state of the read data based on the difference; and determines whether the pressure plate is open or closed based on a determination result of the presence or absence of external light and on the difference.

## Claims

### Claim 1

An image reading device comprising:
a contact glass having a surface on which a document is disposed or along which the document moves;
a reading unit including a light source configured to emit light to the document on the surface of the contact glass and an image sensor configured to receive the light reflected by the document, the reading unit configured to obtain image data according to the light received by the image sensor,
a pressure plate moveable between a posture where the surface of the contact glass is closed and a posture where the surface of the contact glass is opened;
a pressure-plate opening/closing sensor configured to detect whether the pressure plate is closed; and
circuitry configured to
determine a presence or absence of external light input to a space between the pressure plate and the surface of the contact glass based on image data obtained by the reading unit when the light source is turned off,
compare read data of the light emitted from the light source and received by the image sensor when the pressure plate is closed, with reference read data of the light emitted from the light source and received by the image sensor when the pressure plate is completely closed, to determine a difference between the read data and the reference read data, and
determine whether the pressure plate is open or closed based on the presence or absence of the external light and the difference.

### Claim 2 (depends on 1)

The image reading device according to claim 1,
wherein the circuitry determines whether the pressure plate is open or closed only when the pressure-plate opening/closing sensor detects that the pressure plate is closed.

### Claim 3 (depends on 1)

The image reading device according to claim 1,
wherein the circuitry further includes an alarm to report that the pressure plate is open when detecting that the pressure plate is open.

### Claim 4

A method of detecting opening/closing of pressure-plate, used for an image reading device including
a contact glass having a surface on which a document is disposed or along which the document moves,
a reading unit including a light source configured to emit light to the document on the surface of the contact glass and an image sensor configured to receive the light reflected by the document, the reading unit configured to obtain image data according to the light received by the image sensor,
a pressure plate moveable between a posture where the surface of the contact glass is closed and a posture where the surface of the contact glass is opened, and
a pressure-plate opening/closing sensor configured to detect whether the pressure plate is closed,
the method comprising:
determining a presence or absence of external light input to a space between the pressure plate and the surface of the contact glass based on image data obtained by the reading unit when the light source is turned off;
comparing read data of the light emitted from the light source and received by the image sensor when the pressure plate is closed, with reference read data of the light emitted from the light source and received by the image sensor when the pressure plate is completely closed, to determine a difference between the read data and the reference read data; and
determining whether the pressure plate is open or closed based on the presence or absence of the external light and the difference.

### Claim 5 (depends on 1)

An image forming apparatus comprising the image reading device according to claim 1.