U.S. patent application number 11/689115 was filed with the patent office on 2007-09-27 for image reading apparatus, image reading unit thereof, and reference member thereof for shading correction.
This patent application is currently assigned to CANON DENSHI KABUSHIKI KAISHA. Invention is credited to Tetsurou Ishikawa, Shinobu Kato, Takashi Machida, Taketo Ochiai, Jun Tanaka, Keiji Tsutaoka.
Application Number | 20070223061 11/689115 |
Document ID | / |
Family ID | 38533067 |
Filed Date | 2007-09-27 |
United States Patent
Application |
20070223061 |
Kind Code |
A1 |
Tanaka; Jun ; et
al. |
September 27, 2007 |
IMAGE READING APPARATUS, IMAGE READING UNIT THEREOF, AND REFERENCE
MEMBER THEREOF FOR SHADING CORRECTION
Abstract
An image reading apparatus which is capable of performing
accurate shading correction with simple arrangement while
preventing a reference member from being scratched and paper powder
and the like dust from being deposited on the reference member. The
image reading apparatus comprises an image reading unit. In the
image reading unit, a contact glass guides an original on an image
reading location. The contact glass is held by a glass holding
member. A line image sensor reads the image on the original
conveyed on the image reading location, through the contact glass.
The image reading unit further comprises a reference member whose
image is readable by the image sensor, and a moving mechanism to
move the image sensor so as to enable the image sensor to
alternatively read the original and a reference surface of the
reference member.
Inventors: |
Tanaka; Jun; (Chichibu-shi,
JP) ; Machida; Takashi; (Niiza-shi, JP) ;
Kato; Shinobu; (Yokohama-shi, JP) ; Tsutaoka;
Keiji; (Tokyo, JP) ; Ochiai; Taketo; (Tokyo,
JP) ; Ishikawa; Tetsurou; (Tokyo, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
CANON DENSHI KABUSHIKI
KAISHA
Chichibu-shi
JP
|
Family ID: |
38533067 |
Appl. No.: |
11/689115 |
Filed: |
March 21, 2007 |
Current U.S.
Class: |
358/497 |
Current CPC
Class: |
H04N 1/2034 20130101;
H04N 2201/044 20130101; H04N 1/203 20130101 |
Class at
Publication: |
358/497 |
International
Class: |
H04N 1/04 20060101
H04N001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2006 |
JP |
2006-079434 |
Mar 22, 2006 |
JP |
2006-079437 |
Sep 15, 2006 |
JP |
2006-251041 |
Claims
1. An image reading apparatus configured to read an image formed on
an original, while conveying the original along a conveying path,
comprising: an image reading unit including a contact glass
configured to guide an original to an image reading location, a
glass holding member configured to hold said contact glass, an
image sensor configured to read an image on an original conveyed to
the image reading location, through said contact glass, a reference
member whose image is readable by said image sensor, and a moving
mechanism configured to move said image sensor so as to enable said
image sensor to read alternatively the original conveyed on the
image reading location and said reference member, wherein
arrangement of said image sensor and said reference member is so
designed as to make a reference surface of said reference member
isolated from the conveying path.
2. An image reading apparatus according to claim 1, wherein the
reference surface of said reference member is held in close contact
with said contact glass.
3. An image reading apparatus according to claim 1, wherein said
reference member is disposed on said glass holding member.
4. An image reading apparatus configured to read an image formed on
an original, while conveying the original along a conveying path,
comprising: an image reading unit including a contact glass
configured to guide an original to an image reading location, a
glass holding member configured to hold said contact glass, an
image sensor configured to read an image on an original conveyed to
the image reading location, through said contact glass, a reference
member whose image is readable by said image sensor, and a moving
mechanism configured to move at least one of said image sensor and
said reference member relatively so as to enable said image sensor
to read alternatively the original conveyed to the image reading
location and said reference member, wherein arrangement of said
image sensor and said reference member is so designed as to make a
reference surface of said reference member isolated from the
conveying path, and said reference member is disposed on an
original conveying path-side surface of said contact glass.
5. An image reading apparatus configured to read an image formed on
an original, while conveying the original along a conveying path,
comprising: an image reading unit including a contact glass
configured to guide an original to an image reading location, a
glass holding member configured to hold said contact glass, an
image sensor configured to read an image on an original conveyed to
the image reading location, through said contact glass, a reference
member whose image is readable by said image sensor, and a moving
mechanism configured to move at least one of said image sensor and
said reference member relatively so as to enable said image sensor
to read alternatively the original conveyed to the image reading
location and said reference member, wherein arrangement of said
image sensor and said reference member is so designed as to make a
reference surface of said reference member isolated from the
conveying path, and said reference member is fixed to an opposite
surface of an original conveying path-side surface of said contact
glass.
6. An image reading apparatus configured to read an image formed on
an original, while conveying the original along a conveying path,
comprising: an image reading unit including a contact glass
configured to guide an original to an image reading location, a
glass holding member configured to hold said contact glass, an
image sensor configured to read an image on an original conveyed to
the image reading location, through said contact glass, a reference
member whose image is readable by said image sensor, and a moving
mechanism configured to move at least one of said image sensor and
said reference member relatively so as to enable said image sensor
to read alternatively the original conveyed to the image reading
location and said reference member, wherein said reference member
comprises a white coating film formed on an original conveying
path-side surface of said contact glass, and a protective member
covering at least a portion of said white coating film, for
protection of said white coating film.
7. An image reading apparatus configured to read an image formed on
an original, comprising: an image reading unit including a frame
that has an opening formed in an original conveying path side
thereof, and rotatably supports a pivot shaft of an image sensor
housed in said frame, a contact glass disposed on the opening of
said frame, configured to guide the original to an image reading
location thereon, and a reference member disposed within said
frame.
8. An image reading unit provided in an image reading apparatus as
claimed in claim 7.
9. An image reading apparatus for reading an image formed on an
original, while conveying the original, comprising: a contact glass
configured to have an original conveying surface on which an
original reading position and a reference member reading position
exist, and guide the original on the original conveying surface; an
image sensor configured to be capable of moving a reading position
thereof between a position opposed to the original reading position
and a position opposed to the reference member reading position,
and read the image formed on the original through said contact
glass guided on the original conveying surface of said contact
glass; and a shading correction reference member as a white
reference for said image sensor, wherein said shading correction
reference member comprises a white coating film formed on an
original conveying path-side surface of said contact glass, and a
protective member covering at least a portion of said white coating
film, for protection of said white coating film.
10. An image reading apparatus according to claim 9, wherein said
protective member is a substantially white adhesive tape.
11. An image reading apparatus according to claim 9, wherein said
protective member is substantially white, and wherein said shading
correction reference member has a transparent fixing member
provided between said protective member and said white coating
film, for fixing said protective member to a surface of said white
coating film.
12. An image reading apparatus according to claim 9, wherein said
shading correction reference member has a substantially white
fixing member provided between said protective member and said
white coating film, for fixing said protective member to a surface
of said white coating film.
13. An image reading apparatus according to claim 9, wherein said
shading correction reference member has a two-sided adhesive tape
for fixing said protective member, in a manner opposed to said
white coating film, to at least one of a portion of said white
coating film and a portion of said contact glass other than a
portion close to said reference member reading location.
14. An image reading apparatus according to claim 11, wherein said
fixing member is a two-sided adhesive tape.
15. An image reading apparatus according to claim 11, wherein said
fixing member is an adhesive.
16. An image reading apparatus according to claim 11, wherein said
protective member is a sheet form member.
17. An image reading apparatus according to claim 11, wherein said
protective member is a sheet metal member.
18. A shading correction reference member disposed at a reference
member reading location on a contact glass provided in an image
reading apparatus, comprising: a white coating film formed on an
original conveying path-side surface of the contact glass; and a
protective member covering at least a portion of said white coating
film, for protection of said white coating film.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image reading apparatus
configured to read an image formed on an original, while conveying
the original, an image reading unit thereof, and a reference member
thereof for shading correction.
[0003] 2. Description of the Related Art
[0004] In general, in an image reading apparatus configured to read
an image formed on an original, while conveying the original, the
original is illuminated with light from a light source, and
reflected light from the original is focused by a rod lens array or
the like, whereby the image on the original is read e.g. by a line
image sensor. However, due to variations in the amounts of light
from the light source and the variations in the performance of the
rod lens array and variations in the sensitivity of the line image
sensor, it is impossible to perform uniform image reading without
any correction.
[0005] To enable uniform image reading, image data obtained from an
output signal from the line image sensor when an original image is
read is corrected using shading correction data formed based on an
output signal from the line image sensor obtained when a white
reference member is read. When correction data for use in the
correction is captured, light amount adjustment for optimizing the
amount of light emitted from the light source to illuminate an
original, and gain adjustment for optimizing an amplification
factor for amplifying image signal output from the line image
sensor are carried out. Further, it is a general practice to
perform shading correction for correcting the variations in the
amounts of light from the light source and the variations in the
performance of the rod lens array and the variations in the
sensitivity of the line image sensor in association with each pixel
thereof. Hereafter, the correction including the light amount
adjustment and the gain adjustment performed so as to enable the
line image sensor to uniformly read image information from the
original will be referred to as "shading correction".
[0006] In an image reading apparatus of the above-mentioned type, a
member disposed in an original image reading position where the
line image sensor reads an image on an original, for supporting a
conveyed original from the reverse side of the same original has a
color (black in general) other than white for the purpose of
detection of a boundary between the original image and the
background image, detection of a skew-feeding of the original, and
prevention of lack of hiding of a reverse side image of the
original.
[0007] A description will be given of the schematic arrangement and
operation of a conventional typical image reading apparatus with
reference to FIG. 22.
[0008] The image reading apparatus 1000 shown in FIG. 22 is
configured to read image information on an original D by a line
image sensor 110 through a contact glass 150 while conveying the
original D. The image reading apparatus 1000 includes a pickup
roller 2 for picking up originals D, a feed roller 3 for feeding
the originals D picked up by the pickup roller 2, a retard roller 4
for separating the picked-up originals D one from another, and a
registration roller pair 5 and a convey roller pair 7 each formed
by a pair of rollers disposed at respective opposed locations, for
conveying the originals D.
[0009] First, before reading an image on an original D, the image
reading apparatus 1000 moves the line image sensor 110 in a
direction indicated by an arrow S in FIG. 18 and causes the line
image sensor 110 to read a reference member 170. The reference
member 170 is disposed at a location opposed to the line image
sensor 110 having been moved in the direction indicated by the
arrow S.
[0010] Then, image data obtained based on an output from the line
image sensor 110 when the line image sensor 110 has read the
reference member 170 is stored, as shading correction data for
shading correction, in association with each pixel of the line
image sensor 110. Thereafter, the image reading apparatus 1000
returns the line image sensor 110 to its original position
(original image reading position), and causes the line image sensor
110 to read the image on the original D, while conveying the
original D. During the operation for reading the original D, the
image data obtained from the output of the line image sensor 110 is
corrected by shading correction performed with reference to the
correction data stored in advance. It should be noted that whether
or not the line image sensor 110 has been moved to a reference
member reading position for reading the reference member 170 can be
determined based on an output from a position sensor 120. The
position sensor 120 is a means for detecting the position of the
line image sensor 110.
[0011] In the image reading apparatus 1000 configured as above, if
the line image sensor 110 deviates from the exact original image
reading position when the line image sensor 110 returns from the
reference member reading position to the original image reading
position, registration error occurs in original reading. This
registration error is generally prevented by positioning the line
image sensor 110 using the position sensor 120. The above-described
sequential operation is commonly performed in response to an
instruction from a control means, such as a CPU (Control Processing
Unit).
[0012] Some image reading apparatuses are configured such that not
a line image sensor but a reference member is moved between
original reading position and escape position. For example, a
technique has been proposed in which the reference member is
exposed into an original conveying path during a period of
reference member reading, and is retracted to a position where the
reference member does not contact with a conveyed original, during
a period of original reading (see e.g. Japanese Laid-Open Patent
Publication (Kokai) No. 2005-102017).
[0013] Conventionally, the reference member is disposed on the far
side of the original conveying path from the line image sensor, at
a location which enables the line image sensor to read the
reference member.
[0014] However, in the above-described prior art, paper powder and
the like dust comes to stay between the reference member and the
line image sensor as originals are conveyed, to make the reference
member soiled, which can often hinder accurate shading correction.
In such a case, a shading mechanism originally configured to
correct the variations in the sensitivity of the line image sensor
and the variations in the amount of light emitted from the light
source and the variations in the performance of the lens array
cannot operate accurately, causing variations in color and
brightness in a read image. This is a serious problem for an image
forming apparatus.
[0015] For this reason, when accurate shading correction cannot be
performed on images due to the above-mentioned soiling, a first
countermeasure is conventionally taken in which a user cleans the
reference member, and then reading is resumed.
[0016] Further, a second countermeasure has conventionally been
proposed in which the reference member is disposed at a location
which does not face the original conveying path and where dust and
dirt are difficult to attach, and the reference member is moved to
a reading position of the line image sensor when acquisition of
shading correction data is performed using the line image sensor
(see e.g. Japanese Laid-Open Patent Publications (Kokai) No.
H10-304195 and No. 2005-102017).
[0017] A conventional image reading apparatus of another type has
an image reading unit which causes the line image sensor 110 to
slidably move in a direction parallel to the contact glass 150
thereby enable the reading position of the image sensor to move
between the original reading position and the reference member
reading position. This type of image reading apparatus reads image
information from an original D by the line image sensor 110 through
the contact glass 150 while conveying the original D in a direction
indicated by an arrow `a` in FIG. 23. During this operation, a
light source incorporated in the line image sensor 110 illuminate
the original D through the contact glass 150. First, before
starting the reading of the original D, the image reading apparatus
moves the line image sensor 110 in a direction indicated by an
arrow b in FIG. 23, and causes the same to read a surface
(reference surface), which faces the contact glass 150, of the
reference member 170. Then, the image reading apparatus generates
shading correction data for use in shading correction, based on a
signal output from the line image sensor 110 having read the
reference surface, and stores the generated shading correction data
on a pixel-by-pixel basis.
[0018] Thereafter, the image reading apparatus returns the line
image sensor 110 to its original position to read the image on the
original D while conveying the original D in the direction of the
arrow a. During this image reading operation, the image reading
apparatus performs shading correction on image data generated based
on an output signal from the line image sensor 110, by referring to
the shading correction data stored in advance.
[0019] The reference member 170 used here is implemented e.g. by a
white film formed by silk printing or the like.
[0020] Japanese Laid-Open Patent Publication (Kokai) No. S62-098861
discloses a flat bed scanner which uses the aforementioned white
film as the reference member.
[0021] The image reading apparatus disclosed in
[0022] Japanese Laid-Open Patent Publication (Kokai) No.
2005-102017 is advantageous in that originals do not rub against
the reference member during conveyance, and hence the reference
member is difficult to be scratched or soiled. However, paper
powder produced and wafted during an original conveying period can
be deposited on the reference member, which necessitates periodic
cleaning of the reference member. In addition, since paper powder
is very fine, it is difficult to remove the paper powder deposited
on the reference member completely. Further, a mechanism for
causing the reference member to be exposed to the original
conveying path is necessitated, which can cause an increase in the
number of component parts and make the construction of the
apparatus complicated.
[0023] On the other hand, in the conventional image reading
apparatus shown in FIG. 22, since an original D rubs against the
reference member 170 during conveyance, the reference member 170
can be scratched, or dust, such as paper powder and swarf from
rollers, can be attached to the reference member 170. Therefore, if
shading correction is performed with reference to the reference
member 170 deprived of whiteness by being scratched or soiled,
lines or streaks appear on read original images.
[0024] Insofar as the first countermeasure is concerned, image
degradation due to maladjustment of shading correction cannot be
recognized until the read image is viewed. For this reason, in a
case where a large number of originals are continuously read, it is
difficult to recognize image degradation at an early stage of the
reading operation, and it is only after a long time that the
reading operation is restarted. Further, the user has to clean the
reference member manually, which is a nuisance to the user.
[0025] On the other hand, in the case of the second countermeasure,
a traveling path along which the reference member extends
continuous with the original conveying path and a standby location
of the reference member, and hence a tiny amount of dust, such as
paper powder, produced by conveyance of originals can enter the
traveling path and stay thereon. In this case, there is a fear that
the reference member moved into the original conveying path for
shading correction might be soiled by the remaining dust.
[0026] Further, white films formed by coating (painting or
printing) are liable to differ in thickness between individual
units thereof, and even an individual white film is apt to have
variation in thickness depending on the location thereon. The use
of such a white film as a white reference leads to a single image
which is partially degraded due to partial degradation of the image
reading performance or occurrence of an image reading apparatus
degraded in image reading performance.
SUMMARY OF THE INVENTION
[0027] The present invention provides an image reading apparatus
which is capable of performing accurate shading correction with
simple arrangement while preventing a reference member from being
scratched and paper powder and the like dust from being deposited
on the reference member, and an image reading unit thereof, as well
as a shading correction reference member thereof.
[0028] In a first aspect of the present invention, there is
provided an image reading apparatus configured to read an image
formed on an original, while conveying the original along a
conveying path, comprising an image reading unit including a
contact glass configured to guide an original to an image reading
location, a glass holding member configured to hold the contact
glass, an image sensor configured to read an image on an original
conveyed to the image reading location, through the contact glass,
a reference member whose image is readable by the image sensor, and
a moving mechanism configured to move the image sensor so as to
enable the image sensor to alternatively read the original conveyed
on the image reading location and the reference member, wherein
arrangement of the image sensor and the reference member is so
designed as to make the reference surface of said reference member
isolated from the conveying path.
[0029] With the arrangement of the first aspect of the present
invention, the image sensor and the reference member are arranged
such that the reference surface of the reference member is isolated
from the conveying path. More specifically, the reference member is
provided on the original conveying path-side surface of the contact
glass. Further, the reference surface of the reference member is
held in close contact with the contact glass. As a consequence, it
is possible to perform accurate shading correction with the simple
arrangement while preventing the reference member from being
scratched and paper powder and the like dust from being attached to
the reference member.
[0030] The reference surface of the reference member can be held in
close contact with the contact glass.
[0031] The reference member can be disposed on the glass holding
member.
[0032] With the arrangement of this embodiment, the reference
member can be disposed on the glass holding member. As a
consequence, in a state isolated from the conveying path, the
reference surface of the reference member can be protected from
being soiled by paper powder and the like dust. Therefore, it is
possible to perform accurate shading correction and dispense with
cleaning of the reference member.
[0033] In a second aspect of the present invention, there is
provided an image reading apparatus configured to read an image
formed on an original, while conveying the original along a
conveying path, comprising an image reading unit including a
contact glass configured to guide an original to an image reading
location, a glass holding member configured to hold the contact
glass, an image sensor configured to read an image on an original
conveyed to the image reading location, through the contact glass,
a reference member whose image is readable by the image sensor, and
a moving mechanism configured to relatively move the image sensor
and the reference member so as to enable the image sensor to
alternatively read the original conveyed to the image reading
location and the reference member, wherein arrangement of the image
sensor and the reference member is so designed as to make the
reference surface isolated from the conveying path, and the
reference member is disposed on an original conveying path-side
surface of the contact glass.
[0034] With the arrangement of the second aspect of the present
invention, it is possible to obtain the same advantageous effects
as provided by the first aspect of the invention.
[0035] In a third aspect of the present invention, there is
provided an image reading apparatus configured to read an image
formed on an original, while conveying the original along a
conveying path, comprising an image reading unit including a
contact glass configured to guide an original to an image reading
location, a glass holding member configured to hold the contact
glass, an image sensor configured to read an image on an original
conveyed to the image reading location, through the contact glass,
a reference member whose image is readable by the image sensor, and
a moving mechanism configured to relatively move the image sensor
and the reference member so as to enable the image sensor to
alternatively read the original conveyed on the image reading
location and the reference member, wherein arrangement of the image
sensor and the reference member is so designed as to make the
reference surface isolated from the conveying path, and the
reference member is fixed to an opposite surface of the contact
glass from an original conveying path-side surface thereof.
[0036] With the arrangement of the third aspect of the invention,
the reference member is fixed to the opposite surface of the
contact glass from the original conveying path-side surface
thereof. As a consequence, in a state isolated from the conveying
path, the reference surface of the reference member is protected
from being soiled by paper powder and the like dust. Therefore, it
is possible to perform accurate shading correction and dispense
with cleaning of the reference member.
[0037] In a fourth aspect of the present invention, there is
provided an image reading apparatus configured to read an image
formed on an original, while conveying the original along a
conveying path, comprising an image reading unit including a
contact glass configured to guide an original to an image reading
location, a glass holding member configured to hold the contact
glass, an image sensor configured to read an image on an original
conveyed to the image reading location, through the contact glass,
a reference member whose image is readable by the image sensor, and
a moving mechanism configured to relatively move the image sensor
and the reference member so as to enable the image sensor to
alternatively read the original conveyed on the image reading
location and the reference member, wherein the reference member
comprises a white coating film formed on an original conveying
path-side surface of the contact glass, and a protective member
covering at least a portion of the white coating film, for
protection of the white coating film.
[0038] With the arrangement of the fourth aspect of the present
invention, it is possible to obtain the same advantageous effects
as provided by the first aspect of the invention.
[0039] In a fifth aspect of the present invention, there is
provided an image reading apparatus configured to read an image
formed on an original, comprising an image reading unit including a
frame that has an opening formed in an original conveying path side
thereof, and rotatably supports a pivot shaft of an image sensor
housed in the frame, a contact glass disposed on the opening of the
frame, configured to guide the original to an image reading
location thereon, and a reference member disposed within the
frame.
[0040] With the arrangement of the fifth aspect of the present
invention, the image reading unit provided in the image reading
apparatus includes a frame that has an opening formed in an
original conveying path side thereof, and rotatably supports a
pivot shaft of an image sensor housed in the frame, a contact glass
disposed on the opening of the frame, for guiding the original to
an image reading location thereon, and a reference member disposed
within the frame. Therefore, it is possible to prevent paper powder
and the like dust attached to the upper surface of the contact
glass i.e. attached to originals being conveyed out of the frame
from entering the frame and from attaching to the white reference
member. Thus, accurate shading correction can be achieved without
necessitating cleaning of the reference member.
[0041] In a sixth aspect of the present invention, there is
provided an image reading unit provided in the image reading
apparatus according to the fifth aspect of the present
invention.
[0042] With the arrangement of the sixth aspect of the present
invention, it is possible to obtain the same advantageous effects
as provided by the first aspect of the invention.
[0043] In a seventh aspect of the present invention, there is
provided an image reading apparatus for reading an image formed on
an original, while conveying the original, comprising a contact
glass configured to have an original conveying surface on which an
original reading position and a reference member reading position
exist, and guide the original on the original conveying surface, an
image sensor configured to be capable of moving a reading position
thereof between the original reading position and the reference
member reading position, and read the image formed on the original
guided on the original conveying surface, through the contact
glass, and a shading correction reference member as a white
reference for the image sensor, wherein the shading correction
reference member comprises a white coating film formed on an
original conveying path-side surface of the contact glass, and a
protective member covering at least a portion of the white coating
film, for protection of the white coating film.
[0044] With the arrangement of the seventh aspect of the present
invention, the reference member is formed by affixing the
protective member, such as a white tape, to the white coating film,
so that even if the thickness of the white coating film formed by
painting or printing method is not uniform, the protective member,
such as a white tape, or the two-sided tape for affixing the
protective member to the white coating film functions like a back
light to reflect light having passed through the white coating
film, which makes it possible to maintain uniform whiteness of the
reference member, as viewed through the contact glass. This
enhances accuracy in shading correction, and therefore it is
possible to maintain stable image reading performance. Further, the
white coating film does not require high hardness and is allowed to
have a non-uniform thickness, so that it is possible to form the
white coating film by an inexpensive method. The protective member
suffices if only it can reflect light having passed through the
white coating film, and is not required to be formed high
dimensional accuracy. When a durable protective member formed e.g.
of metal is used, it is not necessary to carry out replacement of
the protective member, which provides an image reading apparatus
that is easy to manufacture and maintain.
[0045] The protective member can be a substantially white adhesive
tape.
[0046] The protective member can be substantially white, and the
shading correction reference member can have a transparent fixing
member provided between the protective member and the white coating
film, for fixing the protective member to a surface of the white
coating film.
[0047] The shading correction reference member can have a
substantially white fixing member provided between the protective
member and the white coating film, for fixing the protective member
to a surface of the white coating film.
[0048] The shading correction reference member has a two-sided
adhesive tape for fixing the protective member, in a manner opposed
to the white coating film, to at least one of a portion of the
white coating film and a portion of the contact glass other than a
portion close to the reference member reading location.
[0049] The fixing member can be a two-sided adhesive tape.
[0050] The fixing member can be an adhesive.
[0051] The protective member can be a sheet form member.
[0052] The protective member is a sheet metal member.
[0053] In an eighth aspect of the present invention, there is
provided a shading correction reference member disposed at a
reference member reading location on a contact glass provided in an
image reading apparatus, comprising a white coating film formed on
an original conveying path-side surface of the contact glass, and a
protective member covering at least a portion of the white coating
film, for protection of the white coating film.
[0054] With the arrangement of the eighth aspect of the present
invention, it is possible to obtain the same advantageous effects
as provided by the seventh aspect of the invention.
[0055] The above and other objects, features and advantages of the
invention will become apparent from the following detailed
description taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] FIG. 1 is a schematic side cross-sectional view showing the
internal construction of an image reading apparatus according to a
first embodiment of the present invention.
[0057] FIG. 2 is a schematic block diagram showing the electrical
configuration of the image reading apparatus in FIG. 1.
[0058] FIGS. 3A and 3B are cross-sectional views of an image
reading unit appearing in FIG. 1, in a state during an original
reading period, in which:
[0059] FIG. 3A shows the image reading unit as viewed vertically;
and
[0060] FIG. 3B shows the image reading unit as viewed
horizontally.
[0061] FIGS. 4A and 4B are cross-sectional views of the image
reading unit in a state during a reference member reading period,
in which:
[0062] FIG. 4A shows the image reading unit as viewed vertically;
and
[0063] FIG. 4B shows the image reading unit as viewed
horizontally.
[0064] FIGS. 5A and 5B are views of a drive section appearing in
FIG. 1 and component parts associated therewith as viewed from
above, in which:
[0065] FIG. 5A shows a state during the original reading period;
and
[0066] FIG. 5B shows a state during the reference member reading
period.
[0067] FIGS. 6A and 6B are views of the drive section and component
parts associated therewith, as viewed in an original conveying
direction, in which:
[0068] FIG. 6A shows a state in which the apparatus is closed
during the original reading period; and
[0069] FIG. 6B shows a state in which the apparatus is open during
the reference member reading period.
[0070] FIG. 7 is a diagram showing an output waveform obtained when
an image reading operation is performed by a line image sensor
while a pulse motor is rotated at a constant speed.
[0071] FIGS. 8A and 8B are partial vertical cross-sectional views
showing another example of the image reading unit, in which:
[0072] FIG. 8A shows a state during the original reading period;
and
[0073] FIG. 8B shows a state during the reference member reading
period.
[0074] FIGS. 9A and 9B are partial vertical cross-sectional views
showing still another example of the image reading unit, in
which:
[0075] FIG. 9A shows a state during the original reading period;
and
[0076] FIG. 9B shows a state during the reference member reading
period.
[0077] FIGS. 10A to 10D are partial cross-sectional views showing
an example of the layout of a reference member, in which:
[0078] FIG. 10A shows a case where the reference member is disposed
on an opposite surface of a contact glass from an original
conveying surface thereof;
[0079] FIG. 10B shows a case where the reference member is disposed
on an original conveying surface of a glass holding member;
[0080] FIG. 10C shows a case where the reference member is disposed
on an opposite surface of the glass holding member from the
original conveying surface thereof; and
[0081] FIG. 10D shows a case where a junction part is omitted from
the layout shown in FIG. 10B.
[0082] FIG. 11 is a schematic view of an image reading apparatus
according to a second embodiment of the present invention.
[0083] FIG. 12 is a schematic view of a variation of the image
reading apparatus in FIG. 11.
[0084] FIG. 13 is a schematic view of another variation of the
image reading apparatus in FIG. 11.
[0085] FIG. 14 is a schematic view of a line image sensor provided
in an image reading unit appearing in FIG. 11.
[0086] FIGS. 15A and 15B are cross-sectional views showing the
image reading unit and its surrounding, in which:
[0087] FIG. 15A shows a state during the original reading period;
and
[0088] FIG. 15B shows a state during a shading correction data
acquisition period.
[0089] FIG. 16 is a perspective view of the image reading unit.
[0090] FIG. 17 is a flowchart of a shading correction process
executed by a CPU.
[0091] FIGS. 18A and 18B are cross-sectional views showing the
image reading unit according to a variation and its surrounding, in
which:
[0092] FIG. 18A shows a state during the original reading period;
and
[0093] FIG. 18B shows a state during the shading correction data
acquisition period.
[0094] FIG. 19 is a schematic side view of an image reading
apparatus according to a third embodiment of the present
invention.
[0095] FIG. 20 is a schematic side view of a reference member
appearing in FIG. 19.
[0096] FIG. 21 is a schematic side view of a variation of the
reference member in FIG. 20.
[0097] FIG. 22 is a side view showing the internal construction of
a conventional image reading apparatus.
[0098] FIG. 23 is a schematic side view of an image reading unit of
the conventional image reading apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0099] The present invention will now be described in detail with
reference to the drawings showing preferred embodiments thereof. It
should be noted that the relative arrangement of the components,
the numerical expressions and numerical values set forth in these
embodiments do not limit the scope of the present invention unless
it is specifically stated otherwise.
[0100] FIG. 1 is a schematic side cross-sectional view showing the
internal construction of an image reading apparatus according to a
first embodiment of the present invention. The arrangement of the
image reading apparatus shown in FIG. 1 is given only by way of
example, but it is not limitative.
[0101] As shown in FIG. 1, the image reading apparatus 1 is
comprised of a pickup roller 2 that picks up originals D, a feed
roller 3 that feeds the originals D picked up by the pickup roller
2 into the apparatus 1, a retard roller 4 that separates the
picked-up originals D one by one, a pair of registration rollers 5
disposed at respective locations opposed to each other for
conveying an original D, an image reading unit 61 that reads image
information on the upper surface (surface on a front side) of each
original D conveyed by the registration roller pair 5, an image
reading unit 62 that reads image information on the lower surface
(surface on a reverse side) of each conveyed original D, and a pair
of convey rollers 7 disposed at respective locations downstream of
the image reading units 61 and 62 in a manner opposed to each other
for conveying the original D.
[0102] The image reading apparatus 1 has an upper frame 81
pivotally movable about a pivot shaft 81a and a lower frame 82
supporting the pivot shaft 81a, and coveys the original D through a
space enclosed by the upper frame 81 and the lower frame 82. The
upper frame 81 can be turned (opened/closed) manually so as to
allow an original D conveyed and jammed in the apparatus 1 to be
removed from the apparatus 1.
[0103] The upper frame 81 accommodates the feed roller 3, one of
the registration rollers 5, the image reading unit 61, and one of
the convey rollers 7, while the lower frame 82 accommodates the
retard roller 4, the other one of the registration rollers 5, the
image reading unit 62, and the other one of the convey rollers 7.
Portions (not shown) supporting the pivot shaft 81a are integrally
formed with the lower frame 82, and extend from the respective
sides (toward and away from the viewer viewing FIG. 1) in a manner
sandwiching the upper frame 81.
[0104] The image reading unit 62 is fixed to the lower frame 82. On
the other hand, the image reading unit 61 is movably supported on
the upper frame 81 by a plurality of swing arms 9. Each of the
swing arms 9 has one end thereof supported on the upper frame 81,
and the other end thereof supported on the image reading unit 61.
This makes the image reading unit 61 vertically movable, so that
reading of an image on a thick original and conveyance of the thick
original can be performed smoothly. The one end of each swing arm 9
has a snap-fit structure, which facilitates assembly.
[0105] A driving unit 10 is comprised of a drive mechanism and a
drive motor accommodated in the vicinity of the portions of the
lower frame 82 supporting the pivot shaft 81a, for driving the
protruding portions 18x and 18y of the respective slide cams 18
that protrude from the side surfaces of the respective image
reading units 61 and 62 in the same direction (toward the viewer as
viewed in FIG. 1). The pushing member 19 presses the protruding
portions 18x and 18y to drive these, whereby the image reading
units 61 and 62 are each switched from a state during the original
reading period to a state during the reference member reading
period.
[0106] Next, a description will be given of a sequence of
operations carried out by the image reading apparatus 1 for reading
an image on an original D.
[0107] First, the pushing member 19 as one of component parts
forming the driving unit 10 is caused to press the protruding
portions 18x and 18y to thereby cause the respective image reading
units 61 and 62 to move to the position where the reference
members, referred to hereinafter, are read by the line image
sensors, respectively. The image reading apparatus 1 generates
shading correction data, based on reading signals obtained by the
reading, and stores the generated shading correction data on a
pixel-by-pixel basis. Thereafter, pressing of the protruding
portions 18x and 18y by the pushing member 19 is stopped, and then
originals D are fed into the apparatus 1 by the pickup roller 2 and
the feed roller 3 and are separated one by one by the retard roller
4.
[0108] While being nipped and conveyed (in a sub-scanning
direction) by the registration roller pair 5 and the convey roller
pair 7, each original D is repeatedly scanned by the image reading
units 61 and 62 in a main scanning direction (i.e. in a direction
substantially orthogonal to the original conveying direction),
whereby images on the respective upper and lower surfaces of the
original D are read. It should be noted that during the original
reading period, image data generated based on an output signal from
the line image sensor of each of the image reading units 61 and 62
is subjected to shading correction with reference to the stored
shading correction data. After the images are read, the original D
is nipped and conveyed by the convey roller pair 7 and discharged
out of the apparatus 1. Generation and storage of the shading
correction data may be performed once for all loaded originals D at
the start of reading operation or may be repeatedly performed for
every several originals D.
[0109] FIG. 2 is a schematic block diagram showing the electrical
configuration of the image reading apparatus 1 in FIG. 1.
[0110] In FIG. 2, reference numeral 11 designates the line image
sensor (image sensor) provided in each of the image reading units
61 and 62. Reference numeral 111 designates a light source
incorporated in the line image sensor 11.
[0111] Reference numeral 100 designates an A/D converter section
that performs analog processing, such as amplification and black
level clamp, on the image signals received from the respective line
image sensors 11 and then A/D converts the signals. Reference
numeral 101 designates an image processing section that controls
the line image sensors 11, the light sources 111, the A/D converter
section 100, and so forth, and performs various kinds of image
processing (including shading correction) on image data obtained by
A/D conversion of the image signals.
[0112] Reference numeral 102 designates an image storage section
(image memory) that stores image data. Reference numeral 103
designates an interface section that connects the image processing
section 101 to an external host apparatus, a network, and so forth
via a signal line 109. Reference numeral 104 designates a control
section (CPU) that controls the overall operation of the image
reading apparatus 1. Reference numeral 105 designates a storage
section (working memory) used by the CPU 104 for operation.
[0113] The image processing section 101, the CPU 104, and the
working memory 105 are interconnected by a bus 108. The CPU 104 is
configured to be able to access the image memory 102 via the image
processing section 101. Therefore, the CPU 104 can perform
processing using image data stored in the image memory 102,
according to a program written in the working memory 105.
[0114] Reference numeral 112 designates a conveying motor for
conveying originals D. The conveying motor 112 operates under the
control of a motor driver 107 responsive to an instruction from the
CPU 104. A pulse motor 21 is one of the component parts forming the
driving unit 10. The pulse motor 21 causes rotating motion of the
pushing member 19 to thereby slide the slide cam 18, whereby each
of the line image sensors 11 is moved between an original image
reading position for reading an image on an original D and a
reference member reading position for reading the reference member.
The pulse motor 21 operates under the control of a motor driver 106
responsive to an instruction from the CPU 104.
[0115] Next, the arrangement of the image reading unit 62 appearing
in FIG. 1 will be described with reference to FIGS. 3A and 3B and
FIGS. 4A and 4B.
[0116] FIG. 3A is a vertical partial cross-sectional view of the
image reading unit 62 during the original reading period, while
FIG. 3B is a horizontal partial cross-sectional view of the same.
FIG. 4A is a vertical partial cross-sectional view of the image
reading unit 62 during the reference member reading period, while
FIG. 4B is a horizontal partial cross-sectional view of the same.
The image reading unit 61 and the image reading unit 62 are
identical in construction, and hence a description will be given of
the image reading unit 62 alone.
[0117] As shown in FIGS. 3A and 3B and FIGS. 4A and 4B, the image
reading unit 62 is comprised of the line image sensor 11 that reads
images, a frame 12 that accommodates the line image sensor 11, a
printed circuit board 13 that causes the line image sensor 11 to
operate, a flat cable 14 that connects between the line image
sensor 11 and the printed circuit board 13, a contact glass 15 that
guides an original D to an original image reading location 15a, a
glass holding member 16 that holds the contact glass 15, the
reference member 17 having a white reference surface, the slide cam
18 that moves the line image sensor 11 to a predetermined position,
and a tension spring 22 that urges the slide cam 18 to return the
line image sensor 11 from the predetermined position to its home
position.
[0118] As shown in FIGS. 3A and 4A, the frame 12 is formed with a
through hole 12a through which the flat cable 14 extends. The
through hole 12a is formed to have an eaves shape so as to prevent
the entry of dirt and dust.
[0119] The reference member 17 is disposed on the original
conveying surface of the contact glass 15 at a location different
from the original image reading location 15a. The white reference
lower surface of the reference member 17, as a portion close to the
location corresponding to the reference member reading position, is
held in intimate contact with the contact glass 15 by bonding,
adhesion using an adhesive tape, or any other suitable method.
Alternatively, the reference member 17 may be formed on the contact
glass 15 by coating (painting or printing). Therefore, the white
reference surface is prevented from being damaged even when a
conveyed original D rubs against the reference member 17, or from
losing whiteness due to attachment of paper powder or dirt
thereto.
[0120] The line image sensor 11 has protrusions 11a and 11b each
protruding rearward as viewed in FIG. 3B. The protrusion 11a is
fitted in a cam groove 18a formed in the slide cam 18. Further, the
protrusion 11a is fitted through an elongated hole 12b formed in
the frame 12, whereby the movement of the line image sensor 11 in
the main scanning direction is restricted. On the other hand, the
protrusion 11b is fitted in a cam groove 18b also formed in the
slide cam 18.
[0121] The slide cam 18 is formed with the cam grooves 18a and 18b
in which the protrusions 11a and 11b are fitted, respectively,
elongated holes 18c and 18d in which protrusions 12c and 12d
protruding from the frame 12 are fitted, respectively, and a hook
part 18e to which the tension spring 22 is hooked.
[0122] The slide cam 18 is under tension by the tension spring 22
held on a holding part 12e of the frame 12 by the tension spring 22
under tension acting in a direction indicated by an arrow f in
FIGS. 3B and 4B. During the original reading period, as shown in
FIG. 3B, the protruding portion 18y as one end of the slide cam 18
(the protruding portion 18x in the case of the image reading unit
61) is held in a state protruding from the frame 12. On the other
hand, during the reference member reading period, as shown in FIG.
4B, the protruding portion 18y as one end of the slide cam 18 (the
protruding portion 18x in the case of the image reading unit 61) is
held in a state retracted in the frame 12 of the image reading
units 62.
[0123] The slide cam 18 is thus slidably engaged with the line
image sensor 11, and is driven in the main scanning direction i.e.
the longitudinal direction of the line image sensor 11, whereby the
line image sensor 11 can be moved according to the shapes of the
cam grooves 18a and 18b in the sub scanning direction to one of the
original image reading position and the reference member reading
position.
[0124] Next, the arrangement of the driving unit 10 appearing in
FIG. 1 will be described with reference to FIGS. 5A and 5B and
FIGS. 6A and 6B.
[0125] FIGS. 5A and 5B are views of the driving unit 10 and
component parts associated therewith, as viewed from above, in
which FIG. 5A shows a state during the original reading period, and
FIG. 5B shows a state during the reference member reading
period.
[0126] As shown in FIGS. 5A and 5B, the protruding portion 18x is
an end portion of the slide cam 18 protruding from a side surface
of the image reading unit 62, and the protruding portion 18y is an
end portion of the slide cam 18 protruding from a side surface of
the image reading unit 61.
[0127] The driving unit 10 is comprised of the pushing member 19
for pushing in the protruding portions 18x and 18y, an eccentric
cam 20 for transmitting a driving force to the pushing member 19,
and the pulse motor 21 for rotating the eccentric cam 20 about a
pivot shaft 20b to actuate the pushing member 19.
[0128] The pushing member 19 has a contact surface 19a held in
contact with an eccentric cylindrical surface 20a of the eccentric
cam 20, and the contact surface 19b for being brought into contact
with the protruding portions 18x and 18y. The pushing member 19 is
configured such that the contact surface 19a held in contact with
the eccentric cylindrical surface 20a is pushed by the rotation of
the eccentric cam 20 about the axis of the pivot shaft 20b and is
rotated about the axis of the pivot shaft 19d. When the pushing
member 19 is rotated about the pivot 19d, the ends of the slide
cams 18 (protruding portions 18x and 18y) are protruded from the
respective image reading units 61 and 62 and/or are pressed into
the image reading units 61 and 62, respectively.
[0129] The image reading unit 61 and the image reading unit 62 are
arranged such that the protruding portion 18x of the image reading
unit 61 is positioned farther from the pivot 19d than the
protruding portion 18y of image reading unit 62 so as to make a
difference between the distance from the pivot 19d to the
protruding portion 18x and that from the pivot 19d to the
protruding portion 18y. Since the image reading units 61 and 62 are
thus positioned, during the original reading period, the pushing
member 19 is brought into contact with the protruding portion 18y
as shown in FIG. 5A, but on the other hand, the contact surface 19b
is kept from contact with the protruding portion 18x. As a
consequence, the image reading unit 61 movably supported by the
swing arms 9 is allowed to vertically move smoothly in accordance
with the varying thickness of originals.
[0130] FIGS. 6A and 6B are views of the driving unit 10 and
component parts associated therewith, as viewed in the original
conveying direction, in which FIG. 6A shows a state in which the
apparatus 1 is in closed state during the reference member reading
period, and FIG. 6B shows a state in which the apparatus 1 is
opened during the reference member reading period.
[0131] The state where the apparatus 1 is closed is defined as a
state in which the upper frame 81 and the lower frame 82 are held
in meeting contact with each other as shown in FIG. 1 and the
original conveying passage can normally function. On the other
hand, the state where the apparatus 1 is open is defined as a state
in which the upper frame 81 is in a lifted position by being turned
upward around the pivot shaft 81a, whereby the conveying passage is
kept open for cleaning.
[0132] As shown in FIGS. 6A and 6B, the pushing member 19 has a
sloping surface part 19c formed on a contact portion thereof facing
toward the image reading units 61 and 62, and for contact with the
protruding portion 18x. When the apparatus 1 is opened during the
reference member reading period, since the slide cam 18 is under
tension by the tension spring 22, the protruding portion 18x
pressed in by the pushing member 19 protrudes from the image
reading unit 61 in a state freed from the pressing force of the
pushing member 19. When the apparatus 1 is closed in this state,
there is a fear that the protruding portion 18x and the pushing
member 19 collides with each other, causing breakage, unless the
sloping surface part 19c is not formed on the pushing member
19.
[0133] However, according to the present embodiment, since the
pushing member 19 is formed with the sloping surface part 19c, the
protruding portion 18x protruding from the image reading unit 61 is
pressed in by being brought into abutment with the sloping surface
part 19c during the process of closing the apparatus 1, which makes
it possible to prevent breakage due to collision between the
protruding portion 18x and the pushing member 19. It should be
noted that by forming the end of the protruding portion 18x for
contact with the sloping surface part 19c to have a round shape
(angle R), it is possible to further enhance the effect of
preventing breakage due to collision between the protruding portion
18x and the pushing member 19.
[0134] With this arrangement, the image reading apparatus 1 can
drive the slide cams 18 of the respective two image reading units
61 and 62 by the single driving unit 10. This eliminates the need
for providing each of the two image reading units 61 and 62 with a
motor for driving the associated image reading unit and a driving
force-transmitting mechanism associated with the motor. As a
consequence, a space required for arranging the motor and the
driving force-transmitting mechanism can be reduced to thereby
achieve reduction of the size of the apparatus 1. Further, it is
possible to make the number of component parts of the apparatus 1
smaller than that of the conventional apparatus, thereby reducing
the price of the apparatus 1.
[0135] Furthermore, the slide cams 18 can be externally driven from
outside the respective image reading units 61 and 62 to thereby
shift the position of the associated line image sensor 11, so that
in a case where the image reading apparatus is a single-sided
reading apparatus, it is possible to form the apparatus 1 by the
upper frame 81 accommodating an image reading unit and the lower
frame 82 without an image reading unit, and provide the driving
unit 10 in the lower frame 82. Thus, the degree of freedom in
configuration of the apparatus 1 can be enhanced.
[0136] Next, an operation for detecting an operation starting
position of the pulse motor 21 will be described with reference to
FIG. 7.
[0137] FIG. 7 is a diagram showing an output waveform obtained when
an image reading operation is performed by the line image sensor 11
while the pulse motor 21 is rotated at a constant speed.
Specifically, the diagram shows changes in the output value common
to light-receiving elements of the line image sensor 11 with
respect to the number of steps of the pulse motor 21 (driving
amount of the driving unit 10) counted when an image reading
operation is performed by the line image sensor 11 while rotating
the pulse motor 21 at a constant speed.
[0138] As the pulse motor 21 is caused to perform one rotation, the
line image sensor 11 moves from the position not opposed to the
reference member 17 as shown in FIG. 3A to a position opposed to
the reference member 17 as shown in FIG. 4A, and then returns to
the position not opposed to the reference member 17 as shown in
FIG. 3A. In the meantime, a reading operation is performed by the
line image sensor 11, and the line image sensor output value as
shown in FIG. 7 is stored in the image memory 102. The line image
sensor output value is obtained by converting the line image sensor
output as an analog signal into digital data by the A/D converter
section 100 and then subjecting the digital data to offset
correction.
[0139] The CPU 104 performs processing for detecting a boundary
between image data obtained by reading the reference member 17 in
the position opposed to the reference member 17 and image data read
in the position not opposed to the reference member 17, from the
image data stored in the image memory 102. The CPU 104 stores
information on which pulse of the pulse motor 21 corresponds to the
detected boundary, and calculates a desirable stop position,
whereby it is possible to know the number of steps of the pulse
motor 21 required for moving the line image sensor 11 from the
current operation starting position to the original image reading
position or the reference member reading position. This step count
is equal to the driving amount of the driving unit 10.
[0140] A midpoint (1) between a boundary (A) detected when the line
image sensor 11 has moved from a position not opposed to the
reference member 17 as shown in FIG. 3A to a position opposed to
the reference member 17 as shown in FIG. 4A and a boundary (B)
detected when the line image sensor 11 has moved from the position
opposed to the reference member 17 to a position which ceases to be
opposed to the reference member 17 as shown in FIG. 3A can be
regarded as an optimum position for causing the line image sensor
11 to be opposed to the reference member 17.
[0141] On the other hand, a midpoint (2) between the boundary (B)
detected when the line image sensor 11 has moved from the position
opposed to the reference member 17 as shown in FIG. 4A to the
position not opposed to the reference member 17 as shown in FIG. 3A
and a boundary (C) detected when the line image sensor 11 has moved
from the position not opposed to the reference member 17 to the
position opposed to the reference member 17 as shown in FIG. 4A can
be regarded as an optimum position for causing the line image
sensor 11 to be not opposed to the reference member 17.
[0142] However, the size of the reference member 17 varies with
each image reading apparatus 1. Further, since the reading position
of the line image sensor 11 is moved by the pulse motor 21 via the
pushing member 19 and the slide cam 18, the distance of travel of
the line image sensor 11 varies.
[0143] To detect the optimum positions, the reading operation is
performed while rotating the pulse motor 21 at a constant speed,
and driving amounts L1 and L2 of the pulse motor 21 required for
moving the line image sensor 11 between the boundaries are each
determined as respective step counts based on the changes in the
output value shown in FIG. 7. Thus, driving amounts L+L1' and
L+L1+L2' of the pulse motor 21 required for moving the line image
sensor 11 from the current operation starting position of the pulse
motor 21 to the positions corresponding to the respective midpoints
(1) and (2) can be each determined as respective step counts.
[0144] As described above, it is possible to calculate the driving
amount for moving the line image sensor 11 to the midpoint (1) as a
driving amount for positioning the line image sensor 11 for the
reference member reading operation and the driving amount for
moving the line image sensor 11 to the midpoint (2) as a driving
amount for positioning the line image sensor 11 for the original
image reading operation, respectively. This eliminates the need for
additionally providing a position sensor for detecting the
operation starting position of the line image sensor 11.
[0145] Even when the line image sensor 11 is moved to the position
not opposed to the reference member 17, if an original D or the
like exists on the contact glass 15, the difference in brightness
between the surface of the original D and that of the reference
member 17 becomes so small that the boundaries cannot be detected.
Therefore, in this case, an error message may be displayed to
instruct or urge a user to remove the original D.
[0146] By the way, immediately after the power of the image reading
apparatus 1 is turned on, it is impossible to recognize the current
stop position of the pulse motor 21. This means that the position
of the line image sensor 11 cannot be determined. For this reason,
neither the light amount adjustment of the light source nor the
gain adjustment of the A/D converter section 100 can be performed
at this time point.
[0147] Therefore, in the operation for searching for the boundaries
detected when the line image sensor 11 passing over an area
including a portion opposed to the reference member 17 and a
portion not opposed to the reference member 17, a light amount set
value of the light source, a gain set value of the A/D converter
section 100, and the shading correction data are each set to a
preset initial value (particularly suitably, immediately after
assembling the apparatus 1 in a factory, for example). In
discriminating between a scan image read at "the optimum position
for causing the line image sensor 11 to be opposed to the reference
member 17 (the midpoint (1))" as mentioned above (hereinafter
referred to as "the scan image from the reference member 17") and a
scan image read at the other optimum position for causing the line
image sensor 11 to be not opposed to the reference member 17 (the
midpoint (2))" as mentioned above (hereinafter referred to as "the
scan image from the portion other than reference member 17"), a
method of utilizing the difference in magnitude between an output
from the line image sensor 11 and a predetermined threshold value
can be exemplified as an easy method to employ.
[0148] However, the influence of variation in the amount of light
from the light source or the like can make it impossible to
discriminate between the scan image from the reference member 17
and that from the portion other than the reference member 17 using
the preset initial values or the predetermined threshold value. In
such a case, it is possible to employ a method of storing the
maximum and minimum values of the output from the line image sensor
11 during one rotation of the pulse motor 21, and setting the
average value of the maximum and minimum values to the threshold
value, or a method of changing the light amount set value of the
light source and the gain set value of the A/D converter section
100 such that discrimination between the scan image from the
reference member 17 and that from the portion other than the
reference member 17 can be performed based on a predetermined
threshold value. The gain set value may be changed by adjusting an
amplifier that amplifies an analog signal before A/D conversion, or
by computing digital data after A/D conversion.
[0149] With the above-described arrangement, during the reference
member reading period before execution of the image reading
operation, the image reading apparatus 1 rotates the pulse motor 21
to bring the pushing member 19 and the slide cam 18 into the state
shown in FIG. 5B, thereby moving the line image sensor 11 to the
position opposed to the reference member 17 (see FIG. 4A). Then,
when the line image sensor 11 and the reference member 17 are
opposed to each other such that the reading effective range of the
line image sensor 11 is covered by the reference member 17, the
line image sensor 11 reads the reference member 17. As a
consequence, correction data generated based on the output from the
line image sensor 11 is stored on a pixel-by-pixel basis, as
shading correction data for use in shading correction. Thereafter,
the image reading apparatus 1 rotates the pulse motor 21 to bring
the pushing member 19 and the slide cam 18 into the state shown in
FIG. 5A, thereby moving the line image sensor 11 to the position
not opposed to the reference member 17 (see FIG. 3A).
[0150] According to the above-described embodiment, the line image
sensor 11 and the reference member 17 are arranged such that the
reference surface of the reference member 17 is isolated from the
conveying path for originals D. More specifically, the reference
member 17 is disposed on the original conveying surface of the
contact glass 15, with the reference surface thereof held in
intimate contact with the contact glass 15. This prevents the
reference surface from being scratched, and prevents deposition of
paper powder or the like, which obviates the necessity of cleaning
the reference member 17. This makes it possible to acquire shading
correction data without suffering from degradation of the whiteness
of the reference surface, and perform shading correction with
accuracy.
[0151] Although in the above-described embodiment, only the line
image sensor 11 is moved, this is not limitative. More
specifically, the line image sensor 11 and the glass holding member
16 may be relatively moved to thereby shift the line image sensor
11 between the position opposed to the reference member 17 and the
position not opposed to the reference member 17. For example, the
image reading unit may be configured such that only the glass
holding member 16 is moved during a transition period between the
original reading period shown in FIG. 8A and the reference member
reading period shown in FIG. 8B, or alternatively such that the
line image sensor 11 and the glass holding member 16 are both moved
during the transition period between the original reading period
shown in FIG. 9A and the reference member reading period shown in
FIG. 9B.
[0152] Further, although in the above-described embodiment, the
reference member 17 is provided on the original conveying surface
of the contact glass 15, this is not limitative. More specifically,
the reference member 17 can be disposed at any location on the
contact glass 15 or on the glass holding member 16 insofar as it is
off the original image reading location 15a. For example, as shown
in FIG. 10A, the reference member 17 may be disposed on the
opposite side of the contact glass 15 from the original conveying
surface thereof. Alternatively, the reference member 17 may be
disposed on the original conveying surface of the glass holding
member 16 as shown in FIG. 10B, or on the opposite side of the
glass holding member 16 from the original conveying surface of the
same as shown in FIG. 10C. In the case shown in FIG. 10B, the line
image sensor 11 has to move over a junction part 16a connecting
between the contact glass 15 and the reference member 17, which
increases the distance of travel of the line image sensor 11.
Therefore, the junction part 16a may be omitted as shown in FIG.
10D.
[0153] The reference member 17 disposed as shown in FIGS. 10B and
10D requires sufficient strength and thickness for preventing the
white reference surface thereof from being damaged by conveyed
originals D. In the cases shown in FIGS. 10A and 10C, the white
reference surface of the reference member 17 and the upper surface
of the contact glass 15 as the surface for reading originals D are
different in location from each other, and hence it is desirable to
select a thickness of the contact glass 15 and a shape of the glass
holding member 16 such that the surfaces of the two are both
brought into focus. This is because one of unevenesses which must
be corrected by shading correction is variation in the amount of
light from a rod lens array (not shown), but the profile of the
variation in the light amount (i.e. light amount distribution
profile) becomes different in a position away from a position in
focus, which makes the shading correction inaccurate. When the
variation in the amount of light from the rod lens array is small,
the reference member reading operation can be performed in a
position out of focus.
[0154] In the cases in FIGS. 10A and 10D as well, insofar as the
line image sensor 11 can be eventually moved between the position
opposed to the reference member 17 and the position not opposed to
the reference member 17, it doesn't matter whether the line image
sensor 11, the reference member 17, the glass holding member 16 or
the like moves in the vertical direction or any other direction, or
even perform rotation in the course of travel. Further, in the
cases in FIGS. 10A and 10D, the white reference surface of the
reference member 17 is exposed to the inner side of the image
reading unit 61 (62), and therefore there is no fear of the white
reference surface being damaged or paper powder or dust being
deposited on the white reference surface.
[0155] Although in the above-described embodiment, the sloping
surface part 19c is formed on the pushing member 19 so as to
prevent the protruding portion 18x of the slide cam 18 from being
broken when the apparatus 1 is opened during the reference member
reading period, this is not limitative, but in another embodiment,
the image reading apparatus 1 may be configured such that when the
apparatus 1 is opened/closed during the reference member reading
period, the opening/closing of the apparatus 1 is detected, and the
pulse motor 21 is caused to rotate to bring the pushing member 19
into the state shown in FIG. 5A, thereby preventing breakage of the
protruding portion 18x.
[0156] Detect means for detecting the opening/closing of the
apparatus 1 may be implemented by any type of detector, including a
microswitch, a photo-detector switch, and a magnetic detector
switch. Alternatively, determination as to the opening/closing of
the apparatus 1 may be performed by detecting that the read output
from the line image sensor 11 has assumed a value quite different
from one in the normal state. It is also possible to use a control
means implemented e.g. by the CPU or a combination of the control
means and a special-purpose electric circuit as a detect means for
detecting the opening/closing of the apparatus 1.
[0157] Further, although in the above-described embodiment, the
image reading apparatus is capable of double-sided reading of an
original D, it is to be understood that the present invention can
be applied to an image reading apparatus for single-sided
reading.
[0158] FIG. 11 is a schematic view of an image reading apparatus
according to a second embodiment of the present invention. The
arrangement of the image reading apparatus in FIG. 11 is
illustrated by way of example, and hence this is not
limitative.
[0159] As shown in FIG. 11, the image reading apparatus 1' is
comprised of a pickup roller 2' that picks up originals D, a feed
roller 3' that feeds the originals D picked up by the pickup roller
2' into the apparatus 1', a retard roller 4' that pairs with the
feed roller 3' to separate the picked-up originals D one by one, a
registration roller pair 5' for conveying the originals D while
correcting skew of ones conveyed thereto in a skewed state, a pair
of image reading units 61' and 62' that read images on the
respective upper and lower surfaces of each of the originals D,
convey roller pairs 7' that further convey the originals D, and a
discharge roller pair 8' that discharges the originals D out of the
apparatus. It should be noted that the image reading units 61' and
62' may be disposed at respective different locations in the
original conveying direction instead of being disposed at the same
location as shown in FIG. 11.
[0160] The image reading apparatus 1' is divided into an upper
frame 81' and a lower frame 82' by a conveying path along which
originals D are conveyed. This construction makes it possible to
open the conveying path by rotating the upper frame 81' around a
pivot shaft 81a' manually when jamming of a original D has occurred
in the image reading apparatus 1' during conveyance thereof, and
take out the jammed original from the conveying path.
[0161] In the following embodiment, each of the two image reading
units 61' and 62' reads images on respective originals conveyed,
one by one, by the associated line image sensor in an original
reading position. However, the present invention is not limited to
the present embodiment insofar as the apparatus is provided with at
least one image reading means requiring shading correction.
[0162] Further, in the following embodiment, the height of an
original discharging position with respect to an original stack
position is not particularly limited. For example, the original
discharging position may be provided below the original stack
position as shown in FIG. 12, or alternatively on the opposite side
of the image reading apparatus 1' from the original stack position
as shown in FIG. 13. Further, although in FIG. 11, each original is
passed between the image reading units 61' and 62' by horizontally
moving the original therethrough, the image reading apparatus 1'
may be configured such that original D is passed between the image
reading units 61' and 62' by vertically moving the original D
therethrough.
[0163] FIG. 14 is a schematic view of a line image sensor 44
provided in the image reading unit 62' appearing in FIG. 11.
[0164] It should be noted that the image reading unit 61' is
identical in construction to the image reading unit 62' except that
the image reading unit 61' reads not an image on the lower surface
of the original D but an image on the upper surface of the same,
and hence description thereof is omitted.
[0165] As shown in FIG. 14, the line image sensor 44 incorporates
an LED 442 as a light source, a lens array 443, and a light
receiving element 441.
[0166] In reading an original, the line image sensor 44 causes
reflected light from the original illuminated by the LED 442 to
form an image on the light receiving element 441 by the lens array
443 and converts the image into an electric signal to thereby
generate an image reading signal.
[0167] Next, a description will be given of the arrangement and
configuration of the image reading unit 62'.
[0168] FIGS. 15A and 15B are cross-sectional views showing the
image reading unit 62' and its surrounding in this embodiment, in
which FIG. 15A shows a state during the original reading period,
and FIG. 15B shows a state during a shading correction data
acquisition period.
[0169] As shown in FIGS. 15A and 15B, the image reading unit 62'
has a frame 42 that has an opening formed on a side thereof along
which an original D is conveyed, i.e. an upper side thereof, and
pivotally supports a pivot shaft 45 of the line image sensor 44
accommodated therein. The image reading unit 62' is further
comprised of a contact glass 41 fitted in the opening of the frame
42, for guiding the original D to the original reading location,
and a white reference member 43 for shading correction (hereinafter
simply referred to as "the white reference member 43) disposed
within the frame 42. This arrangement makes it possible to prevent
paper powder and the like dust deposited on an original D conveyed
to the upper surface of the contact glass 41, i.e. the outer side
of the frame 42, from contaminating the internal space of the frame
42 and attaching it to the white reference member 43. Further, the
arrangement makes it possible to carry out a shading correction
process, described in detail hereinafter, accurately without
necessitating cleaning of the white reference member 43.
[0170] The white reference member 43 is disposed such that when the
line image sensor 44 is rotated through 900, the reference surface
of the white reference member 43 faces a reading position of the
line image sensor 44.
[0171] The line image sensor 44 is disposed such that the distance
from the line image sensor 44 to the white reference member 43
during the shading correction data acquisition period (see FIG.
15B) becomes equal to an optical distance from the line image
sensor 44 to the surface of an original D (i.e. a distance
corrected in view of the glass thickness of the contact glass 15
disposed between the line image sensor 44 and the surface of the
original D) in the original image reading period (see FIG. 15A).
This is to equalize the reading conditions of the line image sensor
44, i.e. the focal position and the amount of illuminating light,
between during the original image reading period and during the
shading correction data period.
[0172] Alternatively, the difference in the amount of reflected
light due to the difference in the optical distance may be
corrected, instead of disposing the line image sensor 44 such that
the optical distance is equalized as described above. Reading of
the reference member 43 can be performed even in a position out of
focus, and therefore it is assumed that the reading position
includes positions deviated from the position in focus.
[0173] FIG. 16 is a perspective view of the image reading unit
62'.
[0174] As shown in FIG. 16, the image reading unit 62' has a sensor
rotating mechanism comprised of the pivot shaft 45 and a motor 46,
and is capable of rotating the reading position of the line image
sensor 44 through a desired angle. The sensor rotating mechanism
may include a transmission mechanism comprised of gears or the
like. Further, the motor 46 may be replaced by a solenoid, a rotary
solenoid, or the like actuator.
[0175] FIG. 17 is a flowchart showing the shading correction
process executed by the CPU.
[0176] As shown in FIG. 17, first, when a control means, not shown,
detects that a power switch, not shown, of the image reading
apparatus 1' has been pressed by the user, it turns on the power
supply to the electrical sections and components of the apparatus.
When the power supply is turned on (YES to a step S701), a motor
control section, not shown, drives the motor 46 to rotate the line
image sensor 44 into a state for acquisition of shading correction
data (step S702). When supplied with a driving current, the motor
46 starts rotation to rotate the line image sensor 44 until the
reading position of the line image sensor 44 reaches the position
for shading correction data acquisition (step S703).
[0177] Then, a sensor control section, not shown, delivers to the
line image sensor 44 a control signal for causing the line image
sensor 44 to read the white reference member 43 (step S704). In
response to this control signal, the line image sensor 44 starts
reading the white reference member 43, and generates a reading
signal through the reading operation (step S705). The sensor
control section converts the reading signal into digital data at an
A/D converter section, not shown, to thereby acquire the digital
data as shading correction data for each pixel corresponding to
each elements of the light receiving element 441 (step S706). The
shading correction data may be obtained by performing some
computation on the digital data generated through the A/D
conversion.
[0178] When acquisition of the shading correction data is
completed, the motor control section drives the motor 46 to rotate
the line image sensor 44 into a state for reading of an original
(step S707). When supplied with a driving current, the motor 46
resumes the rotation to rotate the line image sensor 44 until the
reading position of the line image sensor 44 returns to the
position for original reading (step S708).
[0179] Then, when an instruction for starting original reading is
input by the user (YES to a step S709), the sensor control section
delivers to the line image sensor 44 a control signal for causing
the line image sensor 44 to sequentially read conveyed originals
(step S710). Upon reception of this control signal, the line image
sensor 44 starts reading the originals, and sequentially generates
reading signals by reading images on the respective originals D
(step S711). The sensor control section converts the reading
signals into digital data at the A/D converter section, not shown,
to thereby acquire the digital data as original image data (step
S712).
[0180] When acquisition of original image data from entire surface
of one original D to be read in response to the reading instruction
from the user is completed, shading correction is performed on the
original image data based on the acquired shading correction data
(step S713), followed by terminating the present process. It should
be noted that the shading correction data acquisition process may
be started before reading of all the originals to be scanned is
completed.
[0181] According to the present process, first, the line image
sensor 44 is rotated until the reading position thereof reaches the
position for shading correction data acquisition (step S703), and
acquires shading correction data by reading the white reference
member 43 (step S706). Thereafter, the line image sensor 44 is
rotated until the reading position thereof returns to the position
for original reading (step S711), and reads originals D (step
S711). This makes it possible to achieve accurate shading
correction.
[0182] It should be noted, as shown in FIGS. 18A and 18B, that the
sensor rotating mechanism may have a pivot shaft 45' having a
pivotal axis thereof positioned apart from the longitudinal axis of
the line image sensor 44, in place of the pivot shaft 45 having a
pivotal axis thereof positioned close to the longitudinal axis of
the line image sensor 44. This makes it possible to swing the line
image sensor 44 about the pivot shaft 45'.
[0183] As described above, according to the present embodiment, the
line image sensor 44 is configured to perform rotation or swing
motion without performing linear motion. This makes the movement
range of the line image sensor 44 smaller than that in a case where
the line image sensor 44 is configured to perform linear motion,
and hence it is possible to reduce the size of the image reading
unit 62'. Further, the pivotal axis exists as fixed points of the
line image sensor 44, so that by leading a signal line from an area
close to the fixed point, it is possible to prevent occurrence of a
trouble due to a disconnection as a problem to be solved when using
such an apparatus that has a cable led out from the movable part
thereof.
[0184] FIG. 19 is a schematic side view of an image reading
apparatus according to a third embodiment of the present invention.
It should be noted that the arrangement of the image reading
apparatus in FIG. 19 is schematically illustrated by way of
example, and hence this is not limitative.
[0185] As shown in FIG. 19, the image reading apparatus 1'' is
comprised of a pickup roller 2'' that picks up originals D, a feed
roller 3'' that feeds the originals D picked up by the pickup
roller 2'' into the apparatus 1'', a retard roller 4'' that
separates the picked-up originals D one by one, a registration
roller pair 5'' provided for conveying the originals D, a contact
glass 15'' for guiding each original D to an image reading location
15a on an original conveying surface thereof, a reference member
17'' provided as a white reference in a reference member reading
location 8b on the original conveying surface of the contact glass
15'', and a line image sensor 11'' that reads image information on
the original D through the contact glass 15''. Further, the image
reading apparatus 1'' has a convey roller pair 7'' disposed
downstream of the line image sensor 11''.
[0186] The image reading apparatus 1'' is formed by an upper frame
81'' and a lower frame 82'', and the line image sensor 11'' is
supported in the lower frame 82'' in a manner movable between the
image reading location 15a and the reference member reading
location 8b.
[0187] With the above-described arrangement, the image reading
apparatus 1'' performs the following operation for reading images
on respective original D. First, before starting reading of the
originals D, the image reading apparatus 1'' causes a drive
mechanism, not shown, to move the line image sensor 11'' in a
direction indicated by an arrow b from a position opposed to the
image reading location 15a, and reads the reference member 17'' by
the line image sensor 11'' through the contact glass 15'' when the
line image sensor 11'' is brought to a position opposed to the
reference member reading location 8b. A portion of the lower
surface of the reference member 17'' corresponding to the reference
member reading location 8b and the vicinity of the portion provide
the reference surface. Shading correction data generated based on
an output from the line image sensor 11'' having read the reference
member 17'' is stored on a pixel-by-pixel basis. Thereafter, the
image reading apparatus 1'' causes the drive mechanism, not shown,
to return the line image sensor 11'' to the home position i.e. the
image reading location 15a.
[0188] After the above-described operation is completed, the image
reading apparatus 1'' takes in the originals D by the pickup roller
2'' and the feed roller 3'', and separates the originals D, one by
one, by the retard roller 4''. While being nipped and conveyed
(sub-scanned) by the registration roller pair 5 and the convey
roller pair 7, each original D has image information on its lower
surface read by the line image sensor 11'' in a main scanning
direction (i.e. in a direction substantially orthogonal to the
original conveying direction). During the image reading operation,
image data generated based on an output from the line image sensor
11'' is subjected to shading correction with reference to the
aforementioned shading correction data. After image reading is
completed, the original D which nipped and conveyed by the convey
roller pair 7'' is discharged out of the apparatus 1''.
[0189] FIG. 20 is a schematic side view of the reference member
17'' appearing in FIG. 19.
[0190] As shown in FIG. 20, the reference member 17'' is comprised
of a white film 71 formed on the original conveying surface of the
contact glass 15'' by silk printing (a kind of coating method) and
a tape member (adhesive tape) 72 having one adhesive face and
affixed to the upper surface of the white film 71 so as to prevent
the white film 71 from being worn by contact with conveyed
originals D.
[0191] For the tape member 72, there is used a member which looks
white as viewed from the adhesive-face side. When a light source
incorporated in the line image sensor 11'' irradiates light onto
the white film 71 through the contact glass 15'', the tape member
72 reflects only light having passed through the white film 71.
This makes the white film 71 of the reference member 17'', as
viewed through the contact glass 15'' from the side of the line
image sensor 11'', look even whiter, thereby reducing variations in
whiteness (variations within the member itself as well as between
individual units thereof). As a consequence, the whiteness of the
reference member 17'' becomes uniform.
[0192] Although in the above-described embodiment, the white film
71 is formed on the surface of the contact glass 15'' by silk
printing, other methods, such as painting or spray painting (also
included in coating method), may be employed to form the white film
71 on the surface of the contact glass 15''. The contact glass 15''
may be subjected to surface processing e.g. for roughening the
surface of the contact glass 15'' so as to obtain excellent
adhesion of the white film 71 to the contact glass 15''.
[0193] Although in the above-described embodiment, the reference
member 17'' is formed by affixing the white tape member 72 to the
white film 71, it suffices that the color of the tape member 72 is
substantially white. Further, as shown in FIG. 21, the reference
member 17'' may be formed by affixing a sheet form member 74 as a
protective member to the white film 71 using a double-sided
adhesive tape 73. In this case, when the sheet form member 74 is
substantially white, a transparent or white double-sided adhesive
tape 73 is used, and when the sheet form member 74 has a color
other than white, a substantially white double-sided adhesive tape
73 is used.
[0194] The sheet form member 74 may be bonded to the white film 71
by an adhesive. In this case, however, it is required to use a
substantially white sheet form member 74 so as to reduce the
influence of non-uniform application of the substantially white
adhesive. And transparent adhesive also require to use
substantially white sheet form member 74.
[0195] The sheet form member 74 may be formed by a member of sheet
metal, such as stainless, so as to suppress wear of the sheet form
member 74 due to rubbing with originals. When a sheet metal member
having a sufficient thickness is used, the sheet metal member is
fixed to a member other than the contact glass 15'', and hence it
is not required to affix or bond the sheet form member 74 to the
white film 71. In this case, it is more suitable if the lower
surface of the sheet metal is machined so as to cause diffuse
reflection of light. Further, a substantially white sheet or film
may be provided on the lower surface of the sheet metal. Even when
a sheet metal is laid on a white film, as mentioned above, and no
affixing or bonding to the white film is effected, the combination
of the white film and the sheet metal should be considered to be
included in the category of the reference member 17''.
[0196] The sheet form member 74 may be fixed by affixing the
double-sided adhesive tape 73 to a portion of the white film 71 or
the contact glass 15'' around the vicinity of the reference member
reading location 15a without affixing the double-sided adhesive
tape 73 to the white film 71 in the vicinity of the reference
member reading location 15a. In this case, the double-sided
adhesive tape 73 can have any color. Further, the protective
member, such as the metal plate or the sheet metal member, is not
required to cover the whole of the white film 71, but it suffices
that the protective member covers at least a portion thereof
corresponding to reading position of the line image sensor 11'' in
the reference member reading position.
[0197] Although in the above-described embodiment, the line image
sensor 11'' is movable, the image reading apparatus 1'' may be
configured such that the line image sensor 11'' is fixed and the
contact glass is movable, or both can be moved.
[0198] Further, the present invention can also be applied to a flat
bed scanner provided with an original conveying function.
[0199] Furthermore, the image reading apparatus 1'' may be
configured such that the line image sensor 11'' can move its
reading position not by transition or parallel displacement but by
performing rotation or other motion.
[0200] It is to be understood that the object of the present
invention may also be accomplished by supplying a system or an
apparatus with a storage medium in which a program code of
software, which realizes the functions of either of the above
described embodiments is stored, and causing a computer (or CPU or
MPU) of the system or apparatus to read out and execute the program
code stored in the storage medium.
[0201] In this case, the program code itself read from the storage
medium realizes the functions of either of the above described
embodiments, and therefore the program code and the storage medium
in which the program code is stored constitute the present
invention.
[0202] Examples of the storage medium for supplying the program
code include a floppy (registered trademark) disk, a hard disk, a
magnetic-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a
DVD-RAM, a DVD-RW, a DVD+RW, a magnetic tape, a nonvolatile memory
card, and a ROM. Alternatively, the program may be downloaded via a
network.
[0203] Further, it is to be understood that the functions of either
of the above described embodiments may be accomplished not only by
executing the program code read out by a computer, but also by
causing an OS (operating system) or the like which operates on the
computer to perform a part or all of the actual operations based on
instructions of the program code.
[0204] Further, it is to be understood that the functions of either
of the above described embodiments may be accomplished by writing a
program code read out from the storage medium into a memory
provided on an expansion board inserted into a computer or a memory
provided in an expansion unit connected to the computer and then
causing a CPU or the like provided in the expansion board or the
expansion unit to perform a part or all of the actual operations
based on instructions of the program code.
[0205] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all modifications, equivalent
structures and functions.
[0206] This application claims the benefit of Japanese Applications
Nos. 2006-79434 filed Mar. 22, 2006, 2006-79437 filed Mar. 22,
2006, and 2006-251041 filed Sep. 15, 2006, which are hereby
incorporated by reference herein in their entirety.
* * * * *