U.S. patent application number 15/251202 was filed with the patent office on 2016-12-22 for scanner.
The applicant listed for this patent is FUNAI ELECTRIC CO., LTD.. Invention is credited to Ryuichi AIKAWA, Manabu UCHIYAMA.
Application Number | 20160373600 15/251202 |
Document ID | / |
Family ID | 53268720 |
Filed Date | 2016-12-22 |
United States Patent
Application |
20160373600 |
Kind Code |
A1 |
UCHIYAMA; Manabu ; et
al. |
December 22, 2016 |
SCANNER
Abstract
A scanner including: a medium which is conveyed in a first
direction along a conveying path; a read unit disposed in a second
direction perpendicular to the first direction; a light emitting
unit that emits first light to the read unit across the conveying
path; and a detection unit that detects a length of the medium in
the second direction, based on information on an intensity of the
first light detected in the second direction.
Inventors: |
UCHIYAMA; Manabu; (Osaka,
JP) ; AIKAWA; Ryuichi; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUNAI ELECTRIC CO., LTD. |
Osaka |
|
JP |
|
|
Family ID: |
53268720 |
Appl. No.: |
15/251202 |
Filed: |
August 30, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14724317 |
May 28, 2015 |
9438760 |
|
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15251202 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N 1/00734 20130101;
H04N 1/00737 20130101; H04N 2201/0081 20130101; H04N 1/3263
20130101; H04N 1/0075 20130101; H04N 1/00713 20130101; H04N 1/0071
20130101; H04N 1/00769 20130101; H04N 1/00755 20130101; H04N
1/00748 20130101 |
International
Class: |
H04N 1/00 20060101
H04N001/00; H04N 1/32 20060101 H04N001/32 |
Foreign Application Data
Date |
Code |
Application Number |
May 28, 2014 |
JP |
2014-110019 |
Jun 11, 2014 |
JP |
2014-120877 |
May 12, 2015 |
JP |
2015-097709 |
Claims
1. A scanner comprising: a medium which is conveyed in a first
direction along a conveying path; an image read unit disposed
extending in a second direction perpendicular to the first
direction and horizontal to the medium which is conveyed; a first
light emitting unit that emits first light to the image read unit
across the conveying path at a position upstream of the conveying
path relative to a position at which an image is read out from the
medium by the image read unit; and a detection unit that detects a
length of the medium in the second direction, based on an intensity
of the first light received by the image read unit.
2. The scanner according to claim 1, wherein the first light
emitting unit emits the first light in a manner that a direction in
which the first light travels and a direction in which the medium
is conveyed form an acute angle.
3. The scanner according to claim 1, further comprising a second
light emitting unit disposed along a same side as the image read
unit relative to the conveying path, wherein the first light
emitting unit stops emitting the first light after the detection
unit detects the length; the second light emitting unit starts
emitting second light to the medium after the detection unit
detects the length; and the image read unit receives a portion of
the second light reflected by the medium, to read the medium, the
second light being emitted by the second light emitting unit.
4. The scanner according to claim 1, wherein the detection unit
includes a line sensor, and detects the length of the medium in the
second direction, based on the information on the intensity of the
first light received by the line sensor.
5. The scanner according to claim 4, wherein the detection unit
detects the length of the medium in the second direction, based on
whether the intensity of the first light received by the line
sensor is higher than a threshold which is higher than an intensity
of a portion of the first light, emitted by the first light
emitting unit, which has transmitted through the medium and
received by the line sensor, and lower than the first light emitted
by the first light emitting unit and received by the line
sensor.
6. The scanner according to claim 1, further comprising a third
light emitting unit disposed along a same side as the image read
unit relative to the conveying path, wherein the first light
emitting unit includes a reflective unit which reflects, to the
detection unit, a portion of third light emitted by the third light
emitting unit, to send fourth light, and the detection unit detects
an edge of the medium, based on information on an intensity of the
fourth light.
7. The scanner according to claim 6, wherein the detection unit
senses the edge of the medium, based on information on an intensity
of a portion of the third light diffusely reflected by the
medium.
8. The scanner according to claim 7, wherein the image read unit
receives light at a first time and a second time later than the
first time, and if an intensity of the light received by the image
read unit at the first time is higher than a threshold and an
intensity of the light received by the image read unit at the
second time is lower than or equal to the threshold, the detection
unit detects that passage of the edge at a time between the first
time and the second time.
9. The scanner according to claim 8, further comprising a white
surface part having a white surface facing the third light emitting
unit, disposed along an opposite side to the image read unit
relative to the conveying path, wherein the third light emitting
unit emits the third light to the white surface part if the
detection unit detects the edge, and in a state where an opposite
surface of the medium to a read surface is facing the white surface
part, the image read unit receives the portion of the third light
diffusely reflected by the medium, to read the medium.
10. The scanner according to claim 9, wherein the reflective unit
and the white surface part are disposed side by side along the
conveying path, the image read unit is further movable along the
conveying path, the image read unit (i) receives, at a position
facing the reflective unit, the portion of the third light
reflected by the reflective unit, (ii) moves to a position facing
the white surface part if the detection unit detects the edge, and
(iii) reads the medium at the position facing the white surface
part.
11. The scanner according to claim 9, wherein the threshold is
higher than an intensity of a portion of the third light reflected
by the white surface part and received by the image read unit, and
lower than an intensity of the portion of the third light reflected
by the reflective unit and received by the image read unit.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present applications are based on and claim priorities
of Japanese Patent Application No. 2014-110019 filed on May 28,
2014, Japanese Patent Application No. 2014-120877 filed on Jun. 11,
2014, and Japanese Patent Application No. 2015-097709 filed on May
12, 2015. The entire disclosures of the above-identified
applications, including the specifications, drawings and claims are
incorporated herein by reference in their entirety.
FIELD
[0002] The present invention relates to a scanner.
BACKGROUND
[0003] A scanner (generally, also referred to as an image reading
apparatus) which reads an image of a document is known. Also, a
scanner (hereinafter, also referred to as an "ADF scanner"),
equipped with auto document feeder (ADF), which reads images of a
plurality of documents, while sequentially conveying the plurality
of documents to be read, is known.
[0004] Prior to reading a document while conveying it, the ADF
scanner detects a size of the document. One of its purposes is to
detect a document jam. Document jam refers to a failure of a
conveyance mechanism for conveying a document along a conveying
path, which is also known as a manuscript jam or a paper jam.
Occurrence of a document jam may cause folding or tearing of the
document. A scanner can detect a document jam, based on a size of
the document conveyed and a conveyance distance of the
document.
[0005] Patent Literature (PTL) 1 discloses a technique of receiving
light reflected by an edge of the document conveyed, thereby
detecting the edge of the document using a document read
sensor.
CITATION LIST
Patent Literature
[0006] [PTL 1] Japanese Patent No. 5211960
SUMMARY
Technical Problem
[0007] Conventionally, a sensor for detecting a document size and a
sensor for reading the document are separately provided, ending up
with an increase in manufacturing cost.
[0008] Thus, an object of the present invention is to provide a
scanner which properly detects a document size, using a document
read sensor.
Solution to Problem
[0009] To achieve the above object, a scanner according to one
aspect of the present invention is a scanner including: a medium
which is conveyed in a first direction along a conveying path; a
read unit disposed in a second direction perpendicular to the first
direction; a first light emitting unit that emits first light to
the read unit across the conveying path; and a detection unit that
detects a length of the medium in the second direction, based on
information on an intensity of the first light detected in the
second direction.
[0010] According to this configuration, the scanner can detect a
width of a medium based on a position of a portion of the read unit
which the emitted light has failed to reach as a result of the
emitted light being blocked by the medium. The read unit is
disposed in the width direction of the medium perpendicular to the
direction of medium conveyance so as to read media. The position of
the portion of the read unit which does not receive the emitted
light corresponds to the width of the medium which is conveyed.
Thus, the scanner can detect the medium width based on the position
of the portion of the read unit that does not receive the emitted
light, and know the medium size from the medium width using a
predetermined relationship therebetween. Thus, the scanner can
properly detect the medium size.
[0011] For example, the first light emitting unit emits the first
light in a manner that a direction in which the first light travels
and a direction in which the medium is conveyed form an acute
angle.
[0012] According to this configuration, the scanner can detect the
width of a medium, while reducing its effects on the reading of the
medium by the read unit. The light emitting unit is disposed in the
manner that the direction in which the light emitted by the light
emitting unit travels and the direction of medium conveyance form
an acute angle. Thus, the read unit can read the medium as is
conventional after the medium width is detected. Thus, the scanner
can properly detect the medium size, using the read unit.
[0013] For example, the scanner further includes a second light
emitting unit disposed along a same side as the read unit relative
to the conveying path, wherein the first light emitting unit stops
emitting the first light after the detection unit detects the
length; the second light emitting unit starts emitting second light
to the medium after the detection unit detects the length; and the
read unit receives a portion of the second light reflected by the
medium, to read the medium, the second light being emitted by the
second light emitting unit.
[0014] According to this configuration, the scanner can detect a
width of a medium to be read, prior to reading the medium, and
thereafter read the medium as is conventional. Desirably, the read
unit reads the medium, using only the light emitted by the second
light emitting unit disposed along the same side as the read unit
relative to the conveying path, so that the read unit can more
properly read colors of the medium. To that end, the scanner stops
the first light emitting unit from emitting light when the read
unit reads the medium, allowing the read unit to more properly read
an image of the medium.
[0015] For example, the detection unit includes a line sensor, and
detects the length of the medium in the second direction, based on
the information on the intensity of the first light received by the
line sensor.
[0016] According to this configuration, the scanner can detect the
width of the medium based on a position of a portion of the line
sensor, included in the read unit, which has received the emitted
light or a position of a portion of the line sensor which does not
receive the emitted light, as a result of the emitted light being
blocked by the medium and consequently failing to reach the portion
of the line sensor.
[0017] For example, the detection unit detects the length of the
medium in the second direction, based on whether the intensity of
the first light received by the line sensor is higher than a
threshold which is higher than an intensity of a portion of the
first light, emitted by the first light emitting unit, which has
transmitted through the medium and received by the line sensor, and
lower than the first light emitted by the first light emitting unit
and received by the line sensor.
[0018] According to this configuration, the detection unit can
determine, relative to the threshold, an intensity of the light
received by the receiver unit, thereby more properly detecting the
medium width.
[0019] For example, the scanner further includes a third light
emitting unit disposed along a same side as the read unit relative
to the conveying path, wherein the first light emitting unit
includes a reflective unit which reflects, to the detection unit, a
portion of third light emitted by the third light emitting unit, to
send fourth light, and the detection unit detects an edge of the
medium, based on information on an intensity of the fourth
light.
[0020] According to this configuration, the scanner can properly
sense the top edge of the medium, using the read unit mounted on
the scanner to read a medium. The read unit senses the top edge of
the medium, based on whether the read unit receives the light
reflected off the reflective unit. Since the read sensor can detect
the top edge of the medium, the scanner is not required to
separately mount a medium sensor. Thus, the read sensor can be used
also as a medium sensor as well as reducing erroneous detection of
the top edge of a medium.
[0021] For example, the detection unit senses the edge of the
medium, based on information on an intensity of a portion of the
third light diffusely reflected by the medium.
[0022] According to this configuration, the scanner can properly
sense the top edge of a medium, using the read unit mounted thereon
to read media. The read unit receives the light diffusely reflected
by a medium when reading the medium, whereas receiving the light
specularly reflected by the reflective unit if no medium is at the
reading location. The detection unit uses this feature to
distinguish between the light diffusely reflected by a medium and
the light specularly reflected by the reflective unit, and sense
the top edge of the medium when a receiver unit 164 in a state for
receiving light specularly reflected has changed to a state for
receiving light diffusely reflected. The read sensor can detect the
top edge of the medium as such. This obviates the need for
separately mounting a medium sensor. Thus, the read sensor can be
used also as a medium sensor as well as reducing erroneous
detection of the top edge of a medium.
[0023] For example, the read unit receives light at a first time
and a second time later than the first time, and if an intensity of
the light received by the read unit at the first time is higher
than a threshold and an intensity of the light received by the read
unit at the second time is lower than or equal to the threshold,
the detection unit detects that passage of the edge at a time
between the first time and the second time.
[0024] According to this configuration, the scanner senses the top
edge of the medium, based on intensities of the light obtained by
the receiver unit receiving the light two times. Specifically, if
the receiver unit receives the light specularly reflected by the
reflective unit at the first time of the two times, and receives
the light diffusely reflected by the medium at the second time of
the two times, the scanner senses that the top edge of the medium
has passed a predetermined position at a time between the two
times. This can more precisely reduce erroneous detection of the
top edge of a medium.
[0025] For example, the scanner further includes a white surface
part having a white surface facing the third light emitting unit,
disposed along an opposite side to the read unit relative to the
conveying path, wherein the third light emitting unit emits the
third light to the white surface part if the detection unit detects
the edge, and in a state where an opposite surface of the medium to
a read surface is facing the white surface part, the read unit
receives the portion of the third light diffusely reflected by the
medium, to read the medium.
[0026] According to this configuration, the scanner reads a medium,
using a white surface as a background. This allows the scanner to
read colors of the medium more properly.
[0027] For example, the reflective unit and the white surface part
are disposed side by side along the conveying path, the read unit
is further movable along the conveying path, the read unit (i)
receives, at a position facing the reflective unit, the portion of
the third light reflected by the reflective unit, (ii) moves to a
position facing the white surface part if the detection unit
detects the edge, and (iii) reads the medium at the position facing
the white surface part.
[0028] According to this configuration, by moving the read unit,
light emission to the reflective unit and to the white surface part
can be conducted properly.
[0029] For example, the threshold is higher than an intensity of a
portion of the third light reflected by the white surface part and
received by the read unit, and lower than an intensity of the
portion of the third light reflected by the reflective unit and
received by the read unit.
[0030] According to this configuration, the detection unit
determines, relative to the threshold, an intensity of the light
received by the receiver unit, thereby more properly detecting an
edge of the medium. Thus, the scanner can reduce erroneous
detection of the top edge of the medium.
Advantageous Effects
[0031] According to the present invention, a scanner which properly
detects a document size using a document read sensor is
achieved.
BRIEF DESCRIPTION OF DRAWINGS
[0032] These and other objects, advantages and features of the
invention will become apparent from the following description
thereof taken in conjunction with the accompanying drawings that
illustrate a specific embodiment of the present invention.
[0033] FIG. 1 is an external view of a scanner according to an
embodiment 1.
[0034] FIG. 2 is an external view of the scanner according to the
embodiment 1 with a cover unit open.
[0035] FIG. 3 is a bottom view of the cover unit of the scanner
according to the embodiment 1
[0036] FIG. 4 is a top view of a main unit of the scanner according
to the embodiment 1.
[0037] FIG. 5 is a cross-sectional view of the scanner according to
the embodiment 1, taken along V-V in FIG. 1.
[0038] FIG. 6 is a flowchart illustrating a document size detection
process performed by the scanner according to the embodiment 1.
[0039] FIG. 7 is a first schematic diagram illustrating a method
for detecting a document size according to the embodiment 1.
[0040] FIG. 8 is a second schematic diagram illustrating the method
for detecting the document size according to the embodiment 1.
[0041] FIG. 9 is a diagram illustrating processing for detecting a
document width from an intensity of light received by a receiver
unit according to the embodiment 1.
[0042] FIG. 10 is a diagram illustrating correspondence between
document width and document size according to the embodiment 1.
[0043] FIG. 11 is a third schematic diagram illustrating the method
for detecting the document size according to the embodiment 1.
[0044] FIG. 12 is an external view of a scanner according to an
embodiment 2.
[0045] FIG. 13 is a cross-sectional view of the scanner according
to the embodiment 2, taken along XIII-XIII in FIG. 12.
[0046] FIG. 14 is an external view of a scanner according to an
embodiment 3.
[0047] FIG. 15 is an external view of the scanner according to the
embodiment 3 with a cover unit open.
[0048] FIG. 16 is a bottom view of the cover unit of the scanner
according to the embodiment 3.
[0049] FIG. 17 is a top view of a main unit of the scanner
according to the embodiment 3.
[0050] FIG. 18 is a cross-sectional view of the scanner according
to the embodiment 3, taken along XVIII-XVIII in FIG. 14.
[0051] FIG. 19 is a functional block diagram of the scanner
according to the embodiment 3.
[0052] FIG. 20 is a flowchart illustrating a document-edge
detection process performed by the scanner according to the
embodiment 3.
[0053] FIG. 21A is a first schematic diagram illustrating a method
for detecting the top edge of a document, performed by a read unit
according to the embodiment 3.
[0054] FIG. 21B is a second schematic diagram illustrating the
method for detecting the top edge of the document, performed by the
read unit according to the embodiment 3.
[0055] FIG. 22 is a schematic diagram illustrating a method for
reading a document, performed by the read unit according to the
embodiment 3.
[0056] FIG. 23 is an external view of a scanner according to an
embodiment 4.
[0057] FIG. 24 is a cross-sectional view of the scanner according
to the embodiment 4, taken along XXIV-XXIV in FIG. 23.
DESCRIPTION OF EMBODIMENTS
[0058] Hereinafter, embodiments according to the present invention
are to be described, with reference to the accompanying drawings.
The embodiments described below are each merely preferred
illustration of the present invention. Values, shapes, materials,
components, arrangement and connection between the components,
steps, and the order of the steps described in the following
embodiments are merely illustrative and not intended to limit the
present invention. The present invention is indicated by the
appended claims. Thus, among components of the embodiments below,
those not recited in any one of the independent claims are not
necessary to achieve the present invention but are described as
components for preferable embodiments.
Embodiment 1
[0059] In the present embodiment, a scanner which properly detects
a document size, using a document read sensor, will be described.
The scanner is an ADF scanner which reads documents while
sequentially conveying them by ADF. The scanner corresponds to a
scanner. A document is also referred to as a medium.
[0060] FIG. 1 is an external view of the scanner according to the
present embodiment. FIG. 2 is an external view of the scanner
according to the present embodiment with a cover unit open. FIG. 3
is a bottom view of the cover unit of the scanner according to the
present embodiment. FIG. 4 is a top view of a main unit of the
scanner according to the present embodiment.
[0061] As shown in FIGS. 1 and 2, a scanner 1 includes a cover unit
11 and a main unit 15.
[0062] The main unit 15 includes glass platens 24 and 27 and a read
unit 32. FIG. 3 shows a view looking above the main unit 15 from
positive Z-direction. It should be noted that the positive
Z-direction may be referred to as up direction and negative
Z-direction may be referred to as down direction.
[0063] The read unit 32 is a sensor for reading an image of a
document to be read. The read unit 32, specifically, includes a
light emitting unit (not shown, corresponding to a light emitting
unit 62 described below) which emits light for reading a document,
and a receiver unit (not shown, corresponding to a receiver unit 64
described below) which receives light. A portion of the light
emitted by the light emitting unit is reflected by the document to
be read or a roller 36, and received by the receiver unit. In
response to the receipt of the light, the receiver unit outputs a
voltage depending on an intensity of the light received. It should
be noted that the light emitting unit may also be referred to as a
light source B or a second light emitting unit. The light emitted
by the light emitting unit is also referred to as second light.
[0064] The light emitting unit is achieved by a light source such
as a light emitting diode (LED). The light emitting unit may
include a light guide onto which the light from the light source
incident, or an optical system for condensing or diffusing the
light from the light source. The light emitted from the light
emitting unit may have any color (a wavelength), including, for
example, white.
[0065] The receiver unit is achieved by a line image sensor (also,
simply referred to as a line sensor), which is an image sensor
disposed in a main-scan direction (Y direction). The line sensor,
for example, includes a plurality of optical sensors disposed side
by side. The read unit 32 is achieved by, for example, a CIS
(contact image sensor) image sensor or a CCD (charge coupled
device) image sensor.
[0066] In the following, description is given, assuming that the
line sensor includes the plurality of optical sensors disposed side
by side. However, the present invention is not limited to this
configuration. Additionally, the description is given, assuming
that the lengthwise of the receiver unit is perpendicular to a
direction of document conveyance. However, the present invention is
not limited to cases where these directions are strictly
perpendicular to each other, but including cases where they are
substantially perpendicular to each other.
[0067] The read unit 32 is movable in a sub-scan direction (X
direction). The read unit 32 moves to a position underneath the
glass platen 24 to read a document conveyed by ADF. The read unit
32 moves within a region underneath the glass platen 27 to read a
document placed on the glass platen 27.
[0068] The glass platen 24 is a light transmissive member through
which the light emitted by the read unit 32 and its reflected light
pass when the read unit 32 reads the document conveyed by ADF.
[0069] The glass platen 27 is a light transmissive member through
which the light emitted by the read unit 32 and its reflected light
pass when the read unit 32 reads the document placed on the glass
platen 27. The glass platens 24 and 27 are each made of a
transparent glass plate.
[0070] The cover unit 11 includes a paper input tray 12, a paper
output tray 14, a paper input slit 23, a light emitting unit 34,
the roller 36, a paper output slit 25, and a white surface part 28.
FIG. 4 shows a view looking underneath the cover unit 11 from the
negative Z-direction.
[0071] The paper input tray 12 is a tray for placing the document
to be read thereon. A plurality of documents may be placed on the
paper input tray 12. Documents placed on the paper input tray 12
are conveyed by a conveying unit (not shown) sheet-by-sheet,
passing through paper input slit 23 and the paper output slit 25,
to the paper output tray 14. A document is read by, for example,
the read unit 32 between the paper input slit 23 and the paper
output slit 25. The conveying unit is a roller, for example.
[0072] The light emitting unit 34 is a light source which emits
light to the read unit 32. The light emitting unit 34 is used to
detect a length of a document to be read (hereinafter, also
referred to as a document width) in a width direction (Y direction)
perpendicular to the direction of document conveyance (X
direction). The light emitting unit 34, as with the light emitting
unit of the read unit 32, includes an LED, a light guide, an
optical system, or the like. The light emitting unit 34 may also be
referred to as a light source A or a first light emitting unit. The
light emitted by the light emitting unit 34 is also referred to as
first light. Operation of the light emitting unit 34 will be
described in detail below.
[0073] The roller 36 is for holding a document conveyed by ADF
against the glass platen 24 so that the document does not curl up
from the glass platen 24 when the document is read. The roller 36
has a white surface. This allows the read unit 32 to read the
document using the white surface as a background, thereby properly
reading colors of the document.
[0074] The white surface part 28 is a surface used as a background
when the read unit 32 reads a document placed on the glass platen
27. The white surface part 28 has a white surface facing the read
unit 32 for the same reason as for the roller 36.
[0075] The paper output tray 14 is a tray on which a read document
is placed.
[0076] The scanner 1 also includes a detection unit (not shown).
The detection unit detects the document width, based on a position
of a portion of the receiver unit in the width direction of the
document at which the light emitted toward the receiver unit is
blocked by the document.
[0077] FIG. 5 is a cross-sectional view of the scanner according to
the present embodiment, taken along V-V in FIG. 1.
[0078] A conveying path 21 shown in FIG. 5 is a conveying path
extending from the paper input tray 12 to the paper output tray 14,
along which the document to be read is conveyed by a conveying unit
22. The document is conveyed along the conveying path 21, passing
proximate the read unit 32, the light emitting unit 34, etc.
[0079] Plural documents 52 are placed on the paper input tray 12
with faces to be read by the scanner 1 up.
[0080] The conveying unit 22 feeds one sheet of document of the
plural documents 52 placed on the paper input tray 12 by conveying
the document along the conveying path 21. One or more of the
conveying units 22 are provided so as to convey the document along
the conveying path 21.
[0081] The paper input slit 23 is an opening through which a
document is conveyed from the paper input tray 12. A document
having passed through the paper input slit 23 is read while being
conveyed proximate the read unit 32, the light emitting unit 34,
and the roller 36.
[0082] The read unit 32 is provided along one side relative to the
conveying path 21. The light emitting unit 34 and the roller 36 are
provided along the other side relative to the conveying path 21,
the other side being opposite to the side along which the read unit
32 is provided.
[0083] The paper output slit 25 is an opening through which the
read document is conveyed to the paper output tray 14. A document
having passed through the paper output slit 25 is placed on top of
a document 54 on the paper output tray 14.
[0084] FIG. 6 is a flowchart illustrating a document size detection
process performed by the scanner according to the present
embodiment.
[0085] In step S101, the light source A (the light emitting unit
34) starts emitting light. At this point in time, the document to
be read has not reached proximate the read unit 32. The conveying
unit 22 advances the document to be read along the conveying
path.
[0086] In step S102, a width of the document to be read is
detected. At this point in time, the document to be read has
reached proximate the read unit 32. A portion of the light, emitted
by the light emitting unit 34, has reached the receiver unit, and
the rest of the light is blocked by the document or has transmitted
through the document and has reached the receiver unit. Here, the
conveying unit 22 may suspend from conveying the document. This is
so that the width of the document to be read can be accurately
detected.
[0087] In step S103, the light source A stops emitting light. This
is performed if the document width is detected in step S102.
[0088] In step S104, the light source B (the light emitting unit
62) starts emitting light. It should be noted that steps S103 and
S104 may be performed concurrently or step S104 may be performed
prior to step S103.
[0089] In step S105, for example, the read unit 32 reads the
document, utilizing the light emitted from the light source B. The
conveying unit 22 advances the document along the conveying
path.
[0090] In step S106, the scanner 1 stops the light source B from
emitting light. This is performed after the reading of the document
is completed.
[0091] FIG. 7 is a first schematic diagram illustrating the method
for detecting the document size according to the present
embodiment. FIG. 7 shows positional relationship between the
document and the read unit 32 and so on and states of operation of
the read unit 32 and so on in step S101 of FIG. 6.
[0092] As shown in FIG. 7, the read unit 32 includes the light
emitting unit 62 and the receiver unit 64.
[0093] The light emitting unit 62 is disposed at a proper angle at
a proper position for emitting light to a predetermined position on
the conveying path.
[0094] The receiver unit 64 receives light and outputs a voltage
depending on an intensity of the light received. Specifically, the
receiver unit 64 outputs a greater voltage for a higher intensity
of the light received. The receiver unit 64 is disposed at a proper
angle at a proper position for receiving a portion of the light,
emitted by the light emitting unit 62, which has been reflected
(diffusely reflected) by the document. Specifically, the receiver
unit 64 reads the document 61 by reading colors of a document 61 at
a predetermined reading location 68 on the conveying path.
[0095] A detection unit 66 detects the document width, based on a
position, of a portion of the receiver unit 64 in the width
direction of the document, at which the emitted light is blocked by
the document. Specifically, the detection unit 66 detects, as the
width of the document 61, a length of the document in the direction
(Y direction) perpendicular to the direction of document conveyance
(X direction), based on a position of a portion of the receiver
unit 64 that has received the emitted light or a position of a
portion of the receiver unit 64 that has received a portion of the
emitted light that has transmitted through the document 61. It
should be noted that the direction of document conveyance may also
be referred to as a first direction and a direction perpendicular
to the first direction in a plane parallel to a document surface is
also referred to as a second direction.
[0096] Specifically, the detection unit 66 obtains the voltage
output by the receiver unit 64 in response to the receipt of light.
Then, the detection unit 66 determines that the emitted light has
been received by the receiver unit 64 if the obtained voltage is
greater than a predetermined threshold. The detection unit 66
determines that the emitted light is not received by the receiver
unit 64 if the obtained voltage is less than or equal to the
threshold. Herein, the case where the emitted light is not received
by the receiver unit 64 includes a case where the emitted light is
blocked by the document 61 and consequently the receiver unit 64
receives no light, and a case where the emitted light transmits
through the document 61 and consequently the receiver unit 64
receives the transmitted light having a lower intensity than the
emitted light.
[0097] The threshold is set properly to be a value that is lower
than the intensity of the emitted light received by the receiver
unit 64 and higher than the intensity of the transmitted light
received by the receiver unit 64.
[0098] The detection unit 66 detects the width of the document 61,
based on the number of optical sensors, among the plurality of
optical sensors included in the receiver unit 64, which have
received the emitted light as a result of a portion of the emitted
light being blocked by the document 61. It should be noted that, at
this time, the detection unit 66 can, alternatively, detect the
width of the document 61 based on the number of optical sensors
excluding those that have received the emitted light.
[0099] The light emitting unit 34 is disposed at a proper angle at
a proper position for emitting light to the receiver unit 64.
Specifically, the light emitting unit 34 is disposed such that the
direction in which light emitted by the light emitting unit 34
travels and the direction of conveyance of the document 61 form an
acute angle. In doing so, the detection unit 66 can detect the
width of the document 61 and the read unit 32 can thereafter read
an image of the document 61, without the read unit 32 moving.
[0100] The light emitting unit 34 emits the light to the receiver
unit 64. The document 61 has not reached a position above the read
unit 32, and thus does not block the light emitted by the light
emitting unit 34. The receiver unit 64 receives the light emitted
by the light emitting unit 34. Here, the optical sensors included
in the receiver unit 64 receive the light emitted by the light
emitting unit 34, without obstruction by the document 61.
Consequently, the optical sensors each output a voltage exceeding
the threshold.
[0101] The detection unit 66 obtains the voltages output by the
optical sensors included in the receiver unit 64 and determines
that the document 61 has not reached a position above the read unit
32 yet, from a fact that the obtained voltages exceed the
threshold. Thus, at this point in time, the detection unit 66 does
not detect the width of the document 61.
[0102] FIG. 8 is a second schematic diagram illustrating the method
for detecting the document size according to the present
embodiment. FIG. 8 shows positional relationship between the
document and the read unit 32 and so on and states of operation of
the read unit 32 and so on in step S102 of FIG. 6.
[0103] As shown in FIG. 8, the light emitting unit 34 emits light
to the receiver unit 64, as with FIG. 7. The document 61 is
conveyed by the conveying unit 22, having reached a position to
block a portion of the emitted light. However, the document 61 has
not reached the reading location 68 yet. The detection unit 66
detects the width of the document 61 as follows, while an edge of
the document 61 ahead in the forward direction of document
conveyance is behind the reading location 68 in the direction of
document conveyance.
[0104] Some of the optical sensors included in the receiver unit 64
can receive the emitted light while, on the contrary, the remaining
optical sensors cannot since the document 61 is blocking the
emitted light. It should be noted that the remaining optical
sensors receive no light if the document 61 is impervious to light.
On the other hand, if the document 61 is permeable to a portion of
light, the remaining optical sensors receive transmitted light that
has a lower intensity than the emitted light. Thus, the some
optical sensors output voltages greater than the threshold whereas
the remaining optical sensors output voltages lower than the
threshold.
[0105] The detection unit 66 obtains the voltages output by the
plurality of optical sensors included in the receiver unit 64.
Then, the detection unit 66 recognizes that the document is present
above the read unit 32 due to a fact that some of the voltages
obtained are greater than the threshold while the rest of the
voltages are lower than the threshold.
[0106] In this case, the detection unit 66 detects the width of the
document 61, based on the number of optical sensors that have
output voltages greater than the threshold or based on the number
of optical sensors that have output voltages less than or equal to
the threshold.
[0107] FIG. 9 is a diagram illustrating processing for detecting
the document width from an intensity of the light received by the
receiver unit according to the present embodiment. Part (a) of FIG.
9 is a top view of a portion of the main unit 15, including the
glass platen 24, in the positional relationship in step S102 of
FIG. 6.
[0108] As shown in (a) of FIG. 9, the document 61 has been
conveyed, passed underneath the light emitting unit 34, and
approached a position above the read unit 32.
[0109] Part (b) of FIG. 9 depicts voltages output by the plurality
of optical sensors included in the receiver unit 64 in the
positional relationship illustrated in (a) of FIG. 9. The direction
(Y direction) in which the optical sensors are disposed side by
side is indicated on the horizontal axis and the voltages are
indicated on the vertical axis.
[0110] As shown in (b) of FIG. 9, among the plurality of optical
sensors, optical sensors that are at positions where the emitted
light is blocked by the document 61 output lower voltages than a
threshold T, whereas the other optical sensors at the other
positions output voltages greater than the threshold T. The
detection unit 66 detects a document width W (the width in Y
direction), based on the number of optical sensors that have output
the voltages less than the threshold. It is apparent from (b) of
FIG. 9 that the detection unit 66 can, alternatively, detect the
document width W, based on the number of optical sensors that have
output the voltages greater than the threshold.
[0111] FIG. 10 is a diagram illustrating a correspondence chart T10
between a document width and a document size according to the
present embodiment. In the correspondence chart T10, predetermined
types of papers and lengths of sides of the papers (the vertical
length and the horizontal length) are corresponded.
[0112] If detected the document width in step S102, the detection
unit 66 determines whether the document width matches any one of
the lengths of the sides indicated in the correspondence chart T10.
Then, if the document width matches any one of the lengths, the
detection unit 66 may determine the document 61 to be of a
corresponding paper type of the matched length.
[0113] For example, if the detection unit 66 detects the document
width of 210 mm in step S102, the detection unit 66 may determine
the paper type of the document 61 to be "A4." Additionally, the
detection unit 66 may detect the length of the other side (the
length of the document in the direction of document conveyance) of
the document to be 297 mm.
[0114] It should be noted that, considering a reading error, the
determination as to whether the document width W matches any one of
the lengths of the sides in the correspondence chart T10 may permit
an error within about a few percent. Alternatively, even if the
document width W matches none of the lengths in the correspondence
chart T10, a length having a smallest difference from the document
width W or a length having a difference within a predetermined
permissible range in the correspondence chart T10 may be determined
to be the document size.
[0115] FIG. 11 is a third schematic diagram illustrating the method
for detecting the document size according to the present
embodiment. FIG. 11 shows positional relationship between the
document and the read unit 32 and so on and states of operation of
the read unit 32 and so on in step S105 of FIG. 6.
[0116] The light emitting unit 62 emits the light for reading the
document. The document 61 is conveyed by the conveying unit 22 and
a portion of which is on the reading location 68. In other words,
the figure shows a state in which the edge of the document 61 ahead
in the forward direction of document conveyance has already passed
the reading location 68. The document 61 reflects (diffusely
reflects) a portion of the light emitted by the light emitting unit
62. The receiver unit 64 receives the portion of the light, emitted
by the light emitting unit 62, which has been reflected by the
document 61.
[0117] The portion of the light reflected by the document 61
mirrors the colors of the document 61. The receiver unit 64 can
read a read surface of the document 61 by reading the conveyed
document 61 line by line.
[0118] The scanner 1 is configured to detect a document jam, taking
into account the length of the document in the direction of
document conveyance detected by the detection unit 66.
Specifically, if the edge of the document ahead in the forward
direction of document conveyance has passed above the read unit 32
and then the document has been conveyed by the length of the
document in the direction of document conveyance, and the document
is still remaining above the read unit 32, the scanner 1 may
determine that a document jam is occurring on the conveying
path.
[0119] As described above, the scanner according to the present
embodiment can detect a width of a document based on a position of
a portion of the line sensor, included in the document read sensor,
which the emitted light has failed to reach as a result of the
emitted light being blocked by the document. The document read
sensor is disposed in the width direction of the document
perpendicular to the direction of document conveyance so as to read
documents. The positions of the optical sensors forming the line
sensor which do not receive the emitted light correspond to the
width of the document which is conveyed. Thus, the scanner can
detect the document width based on the positions of the optical
sensors that do not receive the emitted light, and know the
document size from the document width using a predetermined
relationship therebetween. Thus, the scanner can properly detect
the document size, using the document read sensor.
[0120] Moreover, the scanner detects the width of a document, while
reducing its effects on the reading of the document by the read
unit. Desirably, when the read unit reads a document, the linear
sensor receives light used only for reading the document. If the
document width is detected while the top edge of the document is
behind the reading location, the read unit can thereafter read the
document as is conventional. Thus, the scanner can properly detect
the document size, using the document read sensor.
[0121] Moreover, the scanner detects the width of a document, while
reducing its effects on the reading of the document by the read
unit. The light emitting unit is disposed in the manner that the
direction in which the light emitted by the light emitting unit
travels and the direction of document conveyance form an acute
angle. Thus, even if the read unit is fixed relative to the
conveying unit, the read unit can read the document as is
conventional after the document width is detected. Thus, the
scanner can properly detect the document size, using the document
read sensor.
[0122] Moreover, the scanner can detect a width of a document to be
read, prior to reading the document, and thereafter read the
document as is conventional. Desirably, the read unit reads the
document, using only the light emitted by the second light emitting
unit disposed along the same side as the read unit relative to the
conveying path so that the read unit can more properly read colors
of the document. To that end, the scanner stops the first light
emitting unit from emitting light when the read unit reads the
document, allowing the read unit to more properly read an image of
the document.
[0123] Moreover, the scanner can detect the width of the document
based on a position of a portion of the line sensor, included in
the document read sensor, which has received the emitted light or a
position of a portion of the line sensor which does not receive the
emitted light, as a result of the emitted light being blocked by
the document and consequently failing to reach the portion of the
line sensor.
[0124] Moreover, the detection unit can determine, relative to the
threshold, an intensity of the light received by the receiver unit,
thereby more properly detecting the document width.
Embodiment 2
[0125] In the present embodiment, a scanner which properly detects
a document size using a document read sensor, will be described.
The scanner is an ADF scanner which reads documents while
sequentially conveying them by ADF from the rear side of the
scanner to the front side.
[0126] FIG. 12 is an external view of the scanner according to the
present embodiment. FIG. 13 is a cross-sectional view of the
scanner according to the present embodiment, taken along XIII-XIII
in FIG. 12.
[0127] As shown in FIGS. 12 and 13, a scanner 2 includes a paper
input tray 12A, a paper output tray 14A, a conveying unit 22A, a
read unit 32A, a light emitting unit 34A, and a roller 36A. The
components referred to by the same reference signs as those
according to the embodiment 1 will be described, focusing on
different functionality. Descriptions of the same features as the
embodiment 1 are omitted.
[0128] The paper input tray 12A is a tray for placing a document to
be read thereon. The paper input tray 12A is provided on the rear
side of the scanner 2. A plurality of documents may be placed on
the paper input tray 12A.
[0129] The paper output tray 14A is a tray on which a read document
is placed. The paper output tray 14A is provided on the front side
of the scanner 2.
[0130] The conveying unit 22A feeds one sheet of document of
documents placed on the paper input tray 12 by conveying the
document along a conveying path 21A. The conveying path 21A is a
substantially linear path extending from the paper input tray 12A
provided on the rear side of the scanner 2 to the paper output tray
14A provided on the front side of the scanner 2.
[0131] The read unit 32A is provided along one side relative to the
conveying path 21A. The light emitting unit 34A and the roller 36A
are provided along the other side relative to the conveying path
21A, the other side being opposite to the side along which the read
unit 32A is provided.
[0132] As described above, according to the present invention, even
an ADF scanner which has the linear conveying path can properly
detect a document size, using the document read sensor.
[0133] While the scanner according to the embodiment of the present
invention has been described above, the present invention is not
limited to the embodiment.
[0134] Some or the whole of the embodiment described above can
also, but not limited to, be described as follows:
[0135] (1) A scanner including: a conveying unit which conveys a
document to be read along a conveying path; a read unit for reading
an image of the document, the read unit including a line sensor in
a width direction of the document, the direction being
perpendicular, in a plane parallel to a document surface of the
document, to a direction in which the document is conveyed; a first
light emitting unit which emits light to the read unit, the first
light emitting unit being disposed in the width direction and along
an opposite side to the read unit relative to the conveying path;
and a detection unit which detects a length of the document in the
width direction, based on a position, in the width direction, of a
portion of the line sensor, at which the light emitted is blocked
by the document.
[0136] (2) The scanner according to (1), wherein the read unit
reads the document by sequentially reading a portion of the light
reflected at a position of a portion of the document conveyed, the
position being at a predetermined reading location on the conveying
path, and the detection unit detects the length of the document in
the width direction while an edge of the document ahead in the
forward direction of document conveyance is behind the reading
location.
[0137] (3) The scanner according to (2), wherein the first light
emitting unit emits the light in a manner that the direction in
which the emitted light travels and the direction of document
conveyance form an acute angle.
[0138] (4) The scanner according to (2) or (3), further includes a
second light emitting unit which emits light to the document
conveyed after the detection unit detects the length, the second
light emitting unit being disposed along the same side as the read
unit relative to the conveying path, wherein the first light
emitting unit stops emitting the light after the detection unit
detects the length, and the read unit reads the document by
receiving, by the line sensor, the portion of the light, emitted by
the second light emitting unit, which has been reflected by the
document.
[0139] (5) The scanner according to any of (1) to (4), wherein the
detection unit detects the length of the document in the width
direction, based on a position of a portion of the line sensor
which has received the light emitted or a position of a portion of
the line sensor, excluding the portion of the line sensor which has
received the light emitted.
[0140] (6) The scanner according to any of (1) to (5), wherein the
detection unit detects the length of the document in the width
direction, based on whether an intensity of the light received by
the line sensor is higher than a threshold which is higher than an
intensity of a portion of the light, emitted by the first light
emitting unit, which has transmitted through the document, and
lower than an intensity of the light emitted by the first light
emitting unit and received by the line sensor.
[0141] According to the above-described (1), the scanner can detect
the width of the document based on the position of the portion of
the line sensor, included in the document read sensor, which the
emitted light has failed to reach as a result of the emitted light
being blocked by document. The document read sensor is disposed in
the width direction perpendicular to the direction of document
conveyance so as to read the document. The position of the portion
of the line sensor included in the document read sensor, which does
not receive the emitted light corresponds to the width of the
document which is conveyed. Thus, the scanner can detect the width
of the document based on positions of the optical sensors that do
not receive the emitted light, and know a document size from the
document width using a predetermined relationship therebetween.
Thus, the scanner can properly detect the document size, using the
document read sensor.
[0142] According to the above-described (2), the scanner detects
the document width, while reducing its effects on the reading of
the document by the read unit. Desirably, when the read unit reads
a document, the linear sensor receives light used only for reading
the document. If the document width is detected while the top edge
of the document is behind the reading location, the read unit can
thereafter read the document as is conventional. Thus, the scanner
can properly detect the document size, using the document read
sensor.
[0143] According to the above-described (3), the scanner detects
the document width, while reducing its effects on the reading of
the document by the read unit. The light emitting unit is disposed
in a manner that the direction in which the light emitted by the
light emitting unit travels and the direction of document
conveyance form an acute angle. Thus, even if the read unit is
fixed relative to the conveying unit, the read unit can read the
document as is conventional after the document width is detected.
Thus, the scanner can properly detect the document size, using the
document read sensor.
[0144] According to the above-described (4), the scanner can detect
a width of a document to be read, prior to reading the document,
and thereafter read the document as is conventional. Desirably, the
read unit reads the document, using only the light emitted by the
second light emitting unit disposed along the same side as the read
unit relative to the conveying path so that the read unit can more
properly read colors of the document. To that end, the scanner
stops the first light emitting unit from emitting light when the
read unit reads the document, allowing the read unit to more
properly read an image of the document.
[0145] According to the above-described (5), the scanner can detect
the width of the document based on a position of a portion of a
line sensor which has received the emitted light or a position of a
portion of the line sensor which does not receive the emitted
light, as a result of the emitted light being blocked by the
document and consequently failing to reach the portion of the line
sensor included in the document read sensor.
[0146] According to the above-described (6), the detection unit
determines, relative to the threshold, an intensity of the light
received by the receiver unit, thereby more properly detecting the
document width.
Embodiment 3
[0147] In the present embodiment, a scanner which properly detects
a size of a document using a document read sensor, and uses the
document read sensor also as a document sensor as well as reducing
erroneous detection of the top edge of the document, will be
described. It should be noted that the scanner may be achieved
independently as a scanner which uses the document read sensor also
as the document sensor as well as reducing an erroneous detection
of the top edge of a document.
[0148] The scanner is an ADF scanner which reads documents while
sequentially passing them by ADF.
[0149] FIG. 14 is an external view of the scanner according to the
present embodiment. FIG. 15 is an external view of the scanner
according to the present embodiment with a cover unit open. FIG. 16
is a bottom view of the cover unit of the scanner according to the
present embodiment. FIG. 17 is a top view of a main unit of the
scanner according to the present embodiment.
[0150] As shown in FIGS. 14 and 15, a scanner 101 includes a cover
unit 111 and a main unit 115.
[0151] The main unit 115 includes glass platens 124 and 127, a read
unit 132, and a moving unit 133. FIG. 16 shows a view looking above
the main unit 115 from positive Z-direction. It should be noted
that the positive Z-direction may be referred to as up direction
and negative Z-direction may be referred to as down direction.
[0152] The read unit 132 is a sensor for reading a document to be
read. The read unit 132, specifically, includes a light emitting
unit (not shown, corresponding to a light emitting unit 162
described below) which emits light for reading the document, and a
receiver unit (not shown, corresponding to a receiver unit 164
described below) which receives a reflected portion of the light
emitted by the light emitting unit. A portion of the light emitted
by the light emitting unit is reflected by the document to be read,
or a reflective unit 134 or a white surface part 136 of the cover
unit 111, and received by the receiver unit. In response to the
receipt of the light, the receiver unit outputs a voltage depending
on an intensity of the light received.
[0153] The light emitting unit is achieved by a light source such
as a light emitting diode (LED). The light emitting unit may
include a light guide onto which the light from the light source
incident, or an optical system for condensing or diffusing the
light from the light source. The light emitted from the light
emitting unit may have any color (a wavelength), including, for
example, white.
[0154] The receiver unit is achieved by a line image sensor, which
is an image sensor aligned in a main-scan direction (Y direction).
The read unit 132 is achieved by, for example, a contact image
sensor (CIS) unit.
[0155] The read unit 132 is mounted on the moving unit 133 and
movable along with a movement of the moving unit 133. The read unit
132 moves to a position underneath the glass platen 124 to read a
document conveyed by ADF. The read unit 132 moves within a region
underneath the glass platen 127 to read a document placed on the
glass platen 127.
[0156] The moving unit 133 is a carriage which moves in a sub-scan
direction (X direction). The moving unit 133 has the read unit 132
mounted thereon and moves to change place of the read unit 132 to a
position so that the read unit 132 can properly read a
document.
[0157] The glass platen 124 is a light transmissive member through
which the light emitted by the read unit 132 and its reflected
light pass when the read unit 132 reads the document conveyed by
ADF.
[0158] The glass platen 127 is a light transmissive member through
which the light emitted by the read unit 132 and its reflected
light pass when the read unit 132 reads the document placed on the
glass platen 127. The glass platens 124 and 127 are each made of a
transparent glass plate.
[0159] The cover unit 111 includes a paper input tray 12, a paper
output tray 114, a paper input slit 123, the reflective unit 134, a
white surface part 36, a paper output slit 125, and a white surface
part 128. FIG. 17 shows a view looking underneath the cover unit
111 from the negative Z-direction.
[0160] The paper input tray 112 is a tray for placing the document
to be read thereon. A plurality of documents may be placed on the
paper input tray 112. Documents placed on the paper input tray 112
are conveyed by a conveying unit (not shown) sheet-by-sheet,
passing through paper input slit 123 and the paper output slit 125,
to the paper output tray 114. A document is read by, for example,
the read unit 132 between the paper input slit 123 and the paper
output slit 125. The conveying unit is a roller, for example.
[0161] The reflective unit 134 is a reflective member which
reflects, to the receiver unit, a portion of the light emitted by
the light emitting unit. The reflective unit 134 is used to detect
the top edge of the document to be read. Desirably, the reflective
unit 134, but not limited to, specularly reflects light. The
reflective unit 134 is made of, for example, a mirror, or a metal
or a stone that is finely polished (mirror finished). Operation of
the reflective unit 134 will be described in detail below. The
reflective unit 134 corresponds to a first light emitting unit.
[0162] The white surface part 136 is a surface used as a background
when a document conveyed by ADF is read. The white surface part 136
has a white surface facing the read unit 132. This allows the read
unit 132 to properly read colors of the document.
[0163] The white surface part 128 is a surface used as a background
when the read unit 132 reads a document placed on the glass platen
127. The white surface part 128 has a white surface facing the read
unit 132 for the same reason as for the white surface part 136.
[0164] The paper output tray 114 is a tray on which a read document
is placed.
[0165] FIG. 18 is a cross-sectional view of the scanner according
to the present embodiment, taken along XVIII-XVIII in FIG. 14.
[0166] A conveying path 121 shown in FIG. 18 is a conveying path
extending from the paper input tray 112 to the paper output tray
114, along which the document to be read is conveyed by a conveying
unit 122. The document is conveyed along the conveying path 121,
passing proximate the read unit 132, the reflective unit 134,
etc.
[0167] Plural documents 152 are placed on the paper input tray 112
with faces to be read up.
[0168] The conveying unit 122 feeds one sheet of document of the
plural documents 152 placed on the paper input tray 112 by
conveying the document along the conveying path 121. One or more of
the conveying units 122 are provided so as to convey the document
along the conveying path 121.
[0169] The paper input slit 123 is an opening through which a
document is conveyed from the paper input tray 112. A document
having passed through the opening is read while being conveyed
proximate the read unit 132, the reflective unit 134, and the white
surface part 136.
[0170] The read unit 132 is provided along one side relative to the
conveying path 121. The reflective unit 134 and the white surface
part 136 are provided along the other side relative to the
conveying path 121, the other side being opposite to the side along
which the read unit 132 is provided.
[0171] The paper output slit 125 is an opening through which the
read document is conveyed to the paper output tray 114. A document
having passed through the paper output slit 125 is placed on a
document 154 on the paper output tray 114.
[0172] FIG. 19 is a functional block diagram of the scanner
according to the present embodiment.
[0173] As shown in FIG. 19, the scanner 101 includes the conveying
unit 122, the read unit 132, the moving unit 133, and a detection
unit 166. The read unit 132 includes a light emitting unit 162 and
a receiver unit 164. The light emitting unit 162 corresponds to a
third light emitting unit. The light emitted by the light emitting
unit 162 is also referred to as third light. It should be noted
that detailed descriptions of the functional blocks already set
forth will be omitted.
[0174] The receiver unit 164 receives light and outputs a voltage
depending on an intensity of the light received. Specifically, the
receiver unit 164 outputs a greater voltage for a higher intensity
of the light received. The receiver unit 164 also determines the
intensity of a portion of the light, emitted by the light emitting
unit 162, which has been reflected off the white surface, to be a
reference value. A voltage output by the receiver unit 164 in
response to the receipt of light that has an intensity equivalent
to the reference value is predetermined to be a reference voltage.
The reference voltage is adjustable and is, for example, 500 mV.
Adjusting the voltage that is output by the receiver unit 164 in
response to the receipt of the light reflected off the white
surface is also expressed as adjusting white balance.
[0175] Given the reference value and the reference voltage
determined as such, a voltage output by the receiver unit 164 in
response to the receipt of the portion of the light, emitted by the
light emitting unit 162, which has been reflected (diffusely
reflected) off a colored surface falls within a range of 0 or
greater and 500 mV or less. A voltage output by the receiver unit
164 in response to the receipt of the portion of the light, emitted
by the light emitting unit 162, which has been reflected
(specularly reflected) off the reflective unit 134 is above the
reference voltage of 500 mV, such as 700 mV, for example. This is
because light specularly reflected has a higher intensity than
light diffusely reflected.
[0176] The detection unit 166 senses whether the top edge of the
document has passed a predetermined position along the conveying
path 121, based on an intensity of the light received by the
receiver unit 164. The predetermined position is a position at
which the read unit 132 reads a portion of the document conveyed.
The detection unit 166 has a threshold voltage to determine whether
the receiver unit 164 has received the light specularly reflected
or whether the receiver unit 164 has received the light diffusely
reflected. The threshold voltage is a predetermined voltage that is
greater than the reference voltage and less than a voltage output
by the receiver unit 164 in response to the receipt of the light
specularly reflected.
[0177] The detection unit 166, specifically, obtains a voltage
output by the receiver unit 164 and compares the obtained voltage
with the threshold voltage to detect the top edge of the document
to be read. If the voltage output by the receiver unit 164 is
greater than the threshold voltage, the detection unit 166
determines that the top edge of the document has not passed the
predetermined position. On the other hand, if the voltage output by
the receiver unit 164 is less than the threshold voltage, the
detection unit 166 determines that the top edge of the document has
already passed the predetermined position and the document is
present at the predetermined position. When the detection unit 166
obtains a voltage output by the receiver unit 164 multiple times
and if detected an obtained voltage that is greater than the
threshold voltage and then detected an voltage that is less than
the threshold voltage, the detection unit 166 detects that the top
edge of the document has passed the predetermined position.
[0178] FIG. 20 is a flowchart illustrating a document-edge
detection process performed by the scanner according to the present
embodiment. Referring to the figure, for example, a process by
which a document is read while being conveyed along the conveying
path 121 is to be described. In step S201, the detection unit 166
adjusts white balance.
[0179] Specifically, the read unit 132 moves to a position
underneath the white surface part 136 or the white surface part
128. Then, the light emitting unit 162 emits light. A portion of
the light is reflected by the white surface part 136 or the white
surface part 128 and received by the receiver unit 164, and then
the receiver unit 164 outputs a voltage depending on an intensity
of the light received. A user adjusts the reference voltage in the
detection unit 166, such that the voltage output by the receiver
unit 164 is 500 mV. It should be noted that the reference voltage
may be adjusted by the detection unit 166 independently.
[0180] In step S202, the conveying unit 122 starts conveying a
document to be read. The processing of steps S203 through S206
(described below) proceeds while the document is being conveyed
along the conveying path.
[0181] In step S203, the read unit 132 moves to a position (a
top-edge sensing location) for detecting the top edge of the
document. Specifically, the top-edge sensing location is a position
at which the receiver unit 164 receives a portion of light, emitted
by the light emitting unit 162, which has been specularly reflected
by the reflective unit 134.
[0182] In steps S204 and S205, the read unit 132 performs detection
operation for detecting the top edge of the document, using the
light emitting unit 162 and the receiver unit 164. The detection
operation is now described in detail, with reference to FIGS. 21A
and 21B.
[0183] FIG. 21A is a first schematic diagram illustrating the
method for detecting the top edge of the document, performed by the
read unit according to the present embodiment. FIG. 21A shows the
scanner 101, magnifying a portion including the read unit 132 which
includes the light emitting unit 162 and the receiver unit 164, and
the reflective unit 34. FIG. 21A shows a state in which a document
161 conveyed along the conveying path 121 has not reached the
predetermined position yet.
[0184] The light emitting unit 162 emits light to a predetermined
position on the conveying path 121.
[0185] The reflective unit 134 is disposed at a predetermined angle
.theta. relative to X axis. The angle .theta. is set to a proper
angle for reflecting, by the reflective unit 134 to the receiver
unit 164, a portion of the light emitted by the light emitting unit
162. Specifically, the angle .theta. depends on installation angles
and installation locations of the light emitting unit 162 and the
receiver unit 164. The position of the read unit 132 shown in FIG.
21A corresponds to the top-edge sensing location.
[0186] As shown in FIG. 21A, prior to the arrival of the top edge
of the document 161 at the predetermined position, the portion of
the light emitted by the light emitting unit 162 travels to the
reflective unit 134 and is specularly reflected by the reflective
unit 134. Then the reflected portion of the light travels to the
receiver unit 164 and is received by the receiver unit 164. Herein,
the portion of the light, emitted by the light emitting unit 162,
which has been reflected by the reflective unit 134, is also
referred to as fourth light. In other words, the reflective unit
134 reflects, to the receiver unit 164 (the read unit 132), the
portion of the light emitted by the light emitting unit 162,
thereby sending the fourth light.
[0187] At this time, the receiver unit 164 outputs a voltage
greater than the reference voltage. The detection unit 166 obtains
the voltage output by the receiver unit 164, and, since the voltage
is greater than the reference voltage, determines that the top edge
of the document 161 has not passed the predetermined position yet.
In this case, the scanner 101 performs the detection operation
(step S205) again.
[0188] FIG. 21B is a second schematic diagram illustrating the
method for detecting the top edge of the document, performed by the
read unit according to the present embodiment. FIG. 21A shows a
state in which the document 161 conveyed along the conveying path
121 has passed the predetermined position.
[0189] As shown in FIG. 21B, the portion of the light emitted by
the light emitting unit 162 is diffusely reflected by the document
161 the top edge of which has passed the predetermined position. A
portion of the diffusely reflected light, which travels to the
receiver unit 164, is received by the receiver unit 164. At this
time, the receiver unit 164 outputs a voltage lower than the
reference voltage. The detection unit 66 obtains the voltage output
by the receiver unit 164 and, since the voltage is lower than the
reference value, determines that the top edge of the document 161
has already passed the predetermined position. In this case, the
scanner 101 ends the detection operation, and proceeds to step
S206.
[0190] It should be noted that if obtained a voltage output by the
receiver unit 164 multiple times, the detection unit 166 can
determine a point in time at which the light emitted by the light
emitting unit 162 is blocked by the document 161 between the state
illustrated in FIG. 21A and the one illustrated in FIG. 21B. The
detection unit 166 can then determine this point in time to be a
point in time at which the top edge of the document 161 has just
passed the predetermined position.
[0191] While the detection unit 166 obtains a voltage multiple
times, it should be noted that obtaining a voltage at least twice
is sufficient for the detection unit 166 to make the above
determination. Specifically, the detection unit 166 obtains a
voltage output by the receiver unit 164 twice, and if an intensity
of the reflected light received by the receiver unit 164 first time
is higher than the threshold and an intensity of the reflected
light received by the receiver unit 164 is lower than or equal to
the threshold, the detection unit 166 senses that the top edge of
the document has passed the predetermined position between the time
at which the first reflected light is received and the time at
which the second reflected light is received.
[0192] Returning to FIG. 20, in step S206, the read unit 132 reads
the document 161. The read operation is now described in detail,
with reference to FIG. 22.
[0193] FIG. 22 is a schematic diagram illustrating a method for
reading a document, performed by the read unit according to the
present embodiment.
[0194] If the top edge of the document 161 is detected in step
S105, the read unit 132 moves to a position underneath the white
surface part 136. The position of the read unit 132 shown in FIG.
22 is also referred to as an ADF reading location.
[0195] The read unit 132 at the ADF reading location reads the
document 161. Here, the reading of the document 161 starts at a
point in time at which the top edge of the document 161 has passed
the predetermined position. This point in time is determined to be
a point in time taken from the point in time at which the detection
unit 66 has detected the top edge of the document 161 in step S205
to a point in time at which the document 161 has been conveyed to
the predetermined position (i.e., a distance between the top-edge
sensing location and the ADF reading location/a conveying
speed).
[0196] Here, the read unit 132 reads the document 161, using the
white surface part 136 as a background, thereby more properly
reading colors of the document 161.
[0197] It should be noted that the read unit 132 does not
necessarily use the white surface part 136 as a background when
reading the document 161. For example, the read unit 132 may stay
at the ADF reading location when reading the document 161, using
the reflective unit 134 as a background. In that case, compared to
when reading the document using the white surface part 136 as a
background, the read unit 132 may not be able to read the colors of
the document properly. This is because the read unit 132 converts
the intensity of the light reflected by the document 161 into
readings (colors), in an attempt to read the document 161 using the
white surface as a background. If the read unit 132 failed to read
the colors accurately, alternatively, right colors can be obtained
by properly correcting the readings.
[0198] It should be noted that the white surface part 136 may be
moved while keeping the position of the read unit 132.
Specifically, the white surface part 136 may be moved to a position
between the reflective unit 134 and the read unit 132. In this case
also, the document 161 can be read, using the white surface part
136 as a background.
[0199] As described above, the scanner according to the present
embodiment can properly sense the top edge of a document, using the
read unit which is mounted thereon to read documents. The read unit
receives the light diffusely reflected by a document when reading
the document, whereas receiving the light specularly reflected by
the reflective unit if no document is at the reading location. The
detection unit uses this feature to distinguish between the light
diffusely reflected by a document and the light specularly
reflected by the reflective unit, and sense the top edge of the
document when the receiver unit 164 in a state for receiving light
specularly reflected has changed to a state for receiving light
diffusely reflected. The read sensor can detect the top edge of the
document as such. This obviates the need for separately mounting a
document sensor. Thus, the read sensor can be used also as a
document sensor as well as reducing erroneous detection of the top
edge of a document.
Embodiment 4
[0200] In the present embodiment, a scanner which properly detects
a size of a document using a document read sensor, and uses the
document read sensor also as a document sensor as well as reducing
erroneous detection of the top edge of the document, will be
described. It should be noted that the scanner may be achieved
independently as a scanner which uses the document read sensor also
as the document sensor as well as reducing an erroneous detection
of the top edge of a document.
[0201] The scanner is an ADF scanner which reads documents while
sequentially passing them by ADF from the rear of the scanner to
the front.
[0202] FIG. 23 is an external view of the scanner according to the
present embodiment. FIG. 24 is a cross-sectional view of the
scanner according to the present embodiment, taken along XXIV-XXIV
in FIG. 23.
[0203] As shown in FIGS. 23 and 24, a scanner 102 includes a paper
input tray 112A, a paper output tray 114A, a conveying unit 122A, a
read unit 132A, the moving unit 133A, a reflective unit 134A, and a
white surface part 136A. The components referred to by the same
reference signs as those according to the embodiment 3 will be
described, focusing on different functionality. Descriptions of the
same features as the embodiment 3 are omitted.
[0204] The paper input tray 112A is a tray for placing the document
to be read thereon. The paper input tray 112A is provided on the
rear side of the scanner 102. A plurality of documents may be
placed on the paper input tray 112A.
[0205] The paper output tray 114A is a tray on which a read
document is placed. The paper output tray 114A is provided on the
front side of the scanner 102.
[0206] The conveying unit 122A feeds one sheet of document of
documents placed on the paper input tray 112A by conveying the
document along a conveying path 121A. The conveying path 121A is a
substantially linear path extending from the paper input tray 112A
provided on the rear side of the scanner 102 to the paper output
tray 114A provided on the front side of the scanner 102.
[0207] The read unit 132A is provided along one side relative to
the conveying path 121A. The reflective unit 134A and the white
surface part 136A are provided along the other side relative to the
conveying path 121A, the other side being opposite to the side
along which the read unit 132A is provided.
[0208] The moving unit 133A moves the read unit 132A along the
conveying path 121A between a position facing the reflective unit
134A and a position facing the white surface part 136A.
[0209] As described above, according to the present invention, even
an ADF scanner which has the linear conveying path can use the read
sensor also as a document sensor as well as reducing erroneous
detection of the top edge of a document.
[0210] Some or the whole of the embodiment described above can, but
not limited to, be described as follows:
[0211] (1) A scanner including: a conveying unit which conveys a
document to be read along a conveying path; a read unit which
includes a light emitting unit which emits light to a predetermined
position on the conveying path and a receiver unit which receives
the light, the read unit being disposed along one side relative to
the conveying path; a reflective unit which reflects, to the
receiver unit, a portion of the light emitted, the reflective unit
being disposed along the other side relative to the conveying path,
the other side being opposite to the side along which the read unit
is disposed; and a detection unit which senses whether an edge of
the document ahead in the forward direction of document conveyance
has passed the predetermined position, based on an intensity of the
light received by the receiver unit.
[0212] (2) The scanner according to (1), wherein the reflective
unit specularly reflects the portion of the emitted light to the
receiver unit, the detection unit detects that the intensity of the
light received by the receiver unit is lower than a threshold as a
result of the portion of the emitted light being diffusely
reflected by the document conveyed to the predetermined position,
thereby sensing that the edge of the document ahead in the forward
direction of document conveyance has passed the predetermined
position.
[0213] (3) The scanner according to (2), wherein the receiver unit
receives the light at a first time and a second time later than the
first time, the detection unit detects that an intensity of the
light received by the receiver unit at the first time is higher
than the threshold and an intensity of the light received by the
receiver unit at the second time is lower than or equal to the
threshold, thereby sensing that the edge has passed the
predetermined position at a time between the first time and the
second time.
[0214] (4) The scanner according to (2) or (3), further includes a
white surface part having a white surface facing the light emitting
unit, the white surface part being disposed along an opposite side
to the read unit relative to the conveying path, wherein the light
emitting unit emits the light to the white surface part if the
detection unit detects the edge, the receiver unit reads the
document by receiving the portion of the light, emitted by the
light emitting unit, which has been diffusely reflected by a read
surface of the document while an opposite surface of the document
to the read surface is facing the white surface part.
[0215] (5) The scanner according to (4), wherein the reflective
unit and the white surface part are disposed side by side along the
conveying path, the read unit is further movable along the
conveying path, the read unit (i) receives, at a position facing
the reflective unit, the light reflected off the reflective unit,
(ii) moves to a position facing the white surface part if the
detection unit detects the edge, and (iii) reads the document at
the position facing the white surface part.
[0216] (6) The scanner according to (4) or (5), wherein the
threshold is higher than the intensity of light, which is a portion
of the emitted light which has been reflected by the white surface
part and received by the receiver unit, and lower than the
intensity of the light which is a portion of the emitted light
which has been reflected by the reflective unit and received by the
receiver unit.
[0217] (7) The scanner according to (1) to (6), wherein the read
unit is a contact image sensor (CIS) unit.
[0218] According to the above-described (1), the scanner can
properly sense the top edge of the document, using the read unit
mounted on the scanner to read a document. The read unit senses the
top edge of the document, based on whether the read unit receives
the light reflected off the reflective unit. Since the read sensor
can detect the top edge of the document, the scanner is not
required to separately mount a document sensor. Thus, the read
sensor can be used also as a document sensor as well as reducing
erroneous detection of the top edge of a document.
[0219] According to the above-described (2), the scanner can
properly sense the top edge of a document, using the read unit
mounted thereon to read documents. The read unit receives the light
diffusely reflected by a document when reading the document,
whereas receiving the light specularly reflected by the reflective
unit if no document is at the reading location. The detection unit
uses this feature to distinguish between the light diffusely
reflected by a document and the light specularly reflected by the
reflective unit, and sense the top edge of the document when the
receiver unit 164 in a state for receiving light specularly
reflected has changed to a state for receiving light diffusely
reflected. The read sensor can detect the top edge of the document
as such. This obviates the need for separately mounting a document
sensor. Thus, the read sensor can be used also as a document sensor
as well as reducing erroneous detection of the top edge of a
document.
[0220] According to the above-described (3), the scanner senses the
top edge of the document, based on intensities of the light
obtained by the receiver unit receiving the light two times.
Specifically, if the receiver unit receives the light specularly
reflected by the reflective unit at the first time of the two
times, and receives the light diffusely reflected by the document
at the second time of the two times, the scanner senses that the
top edge of the document has passed a predetermined position at a
time between the two times. This can more precisely reduce
erroneous detection of the top edge of a document.
[0221] According to the above-described (4), the scanner reads a
document, using a white surface as a background. This allows the
scanner to read colors of the document more properly.
[0222] According to the above-described (5), by moving the read
unit, light emission to the reflective unit and to the white
surface part can be conducted properly.
[0223] According to the above-described (6), the detection unit
determines, relative to the threshold, an intensity of the light
received by the receiver unit, thereby more properly detecting an
edge of the document. Thus, the scanner can reduce erroneous
detection of the top edge of the document.
[0224] According to the above-described (7), using a CIS unit
included in a conventional scanner, the scanner can use the read
sensor also as the document sensor as well as reducing erroneous
detection of the top edge of a document.
[0225] Moreover, each of the devices described above may be
configured as, specifically, a computer system which includes a
microprocessor, a read only memory (ROM), a random access memory
(RAM), a hard disk drive, a display unit, a keyboard, a mouse, etc.
The RAM or the hard disk drive stores a computer program. Each
device performs its functionality by the microprocessor operating
according to the computer program. Here, the computer program is,
to achieve predetermined functionality, a combination of
instruction codes indicating instructions to the computer.
[0226] Furthermore, some or the whole of the components included in
each of the devices described above may be formed by one system LSI
(Large Scale Integration). The system LSI is a super multi-function
LSI fabricated by integrating a plurality of components on one
chip, and is, specifically, a computer system which includes a
microprocessor, a ROM, a RAM, etc. The RAM stores a computer
program. The system LSI performs its functionality by the
microprocessor operating according to the computer program.
[0227] Furthermore, some or the whole of the components included in
each of the devices described above may be formed by an IC card or
a single module detachable from the device. The IC card or the
module is a computer system which includes a microprocessor, a ROM,
a RAM, etc. The IC card or the module may include the super
multi-function LSI described above. The IC card or the module
performs its functionality by the microprocessor operating
according to a computer program. The IC card or the module may be
of tamper-resistant.
[0228] Moreover, the present invention may be implemented in the
methods described above. Moreover, the present invention may be
achieved in a computer program implementing such methods via a
computer, or may be implemented in a digital signal including the
computer program.
[0229] Furthermore, the present invention may be achieved in a
non-transitory computer-readable recording medium storing the
computer program or the digital signal, such as a flexible disk, a
hard disk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, BD (Blu-ray
(registered trademark) Disc), and a semiconductor memory.
Alternatively, the present invention may be implemented in the
digital signal stored in such a non-transitory recording
medium.
[0230] Moreover, the present invention may be achieved in
transmitting the computer program or the digital signal via an
electric communication line, a wireless or wired communication
line, a network represented by the Internet, data broadcast,
etc.
[0231] Moreover, the present invention may be achieved in a
computer system which includes a microprocessor and a memory. The
memory may store the computer program and the microprocessor may
operate according to the computer program.
[0232] Moreover, the program or the digital signal may be
transferred via the network or the like or transferred in the
non-transitory recording medium, and executed in another
independent computer system.
[0233] Furthermore, the above-described embodiments may be
combined.
[0234] Although only some exemplary embodiments of the present
invention have been described in detail above, those skilled in the
art will readily appreciate that many modifications are possible in
the exemplary embodiments without materially departing from the
novel teachings and advantages of the present invention.
Accordingly, all such modifications are intended to be included
within the scope of the present invention.
INDUSTRIAL APPLICABILITY
[0235] The present invention is applicable to a scanner which
properly detects a document size, using a document read sensor.
Specifically, the present invention is applicable to an ADF
scanner.
* * * * *