U.S. patent application number 16/664300 was filed with the patent office on 2020-02-20 for image reading device and image forming apparatus including the same.
The applicant listed for this patent is SHARP KABUSHIKI KAISHA. Invention is credited to SHOHICHI FUKUTOME, KENJI NAKANISHI, YASUHIRO SUTO, HISASHI YAMANAKA.
Application Number | 20200059570 16/664300 |
Document ID | / |
Family ID | 67060035 |
Filed Date | 2020-02-20 |
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United States Patent
Application |
20200059570 |
Kind Code |
A1 |
SUTO; YASUHIRO ; et
al. |
February 20, 2020 |
IMAGE READING DEVICE AND IMAGE FORMING APPARATUS INCLUDING THE
SAME
Abstract
An image reading device includes an image reader that scans a
document so as to read an image of the document. The image reader
includes a scanning body in which at least plural mirrors, a
condenser lens, and an image sensor are disposed. In the scanning
body, concerning positional relationships among the plural mirrors
as viewed from a main scanning direction, the plural mirrors are
disposed on two sides with respect to an imaginary line extending
along an optical axis of reflected light from the document. The
mirrors on a corresponding one of the two sides are disposed such
that a reflecting position of a mirror on a downstream side in a
traveling direction of the reflected light is positioned closer to
the document and also to the imaginary line than that of a mirror
on an upstream side in the traveling direction of the reflected
light.
Inventors: |
SUTO; YASUHIRO; (Sakai City,
JP) ; NAKANISHI; KENJI; (Sakai City, JP) ;
YAMANAKA; HISASHI; (Sakai City, JP) ; FUKUTOME;
SHOHICHI; (Sakai City, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHARP KABUSHIKI KAISHA |
Sakai City |
|
JP |
|
|
Family ID: |
67060035 |
Appl. No.: |
16/664300 |
Filed: |
October 25, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16218189 |
Dec 12, 2018 |
10477058 |
|
|
16664300 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 26/10 20130101;
G02B 17/06 20130101; H04N 1/0285 20130101; H04N 1/0283 20130101;
G02B 17/023 20130101; G02B 7/182 20130101 |
International
Class: |
H04N 1/028 20060101
H04N001/028; G02B 17/06 20060101 G02B017/06; G02B 7/182 20060101
G02B007/182 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2017 |
JP |
2017-253607 |
Claims
1. An image reading device comprising: an image reader that scans a
document so as to read an image of the document, the image reader
including a scanning body in which at least a light source, a
plurality of mirrors, a condenser lens, and an image sensor are
disposed, wherein the plurality of mirrors include at least a first
mirror on which reflected light from the document is incident
first, and a second mirror, in a traveling direction of the
reflected light, disposed on a downstream side from the first
mirror, the first mirror and the second mirror each include a
reflecting surface which reflects the reflected light, so as to
face each other, the first mirror is arranged closer to the
document than another mirror other than the second mirror, and the
second mirror is arranged closer to the document than the first
mirror.
2. The image reading device according to claim 1, wherein,
concerning positional relationships among the plurality of mirrors
as viewed from a main scanning direction, the plurality of mirrors
are disposed on two sides with respect to an imaginary line
extending along an optical axis of the reflected light from the
document, and the second mirror is positioned closer to the
document and also to the imaginary line than a third mirror
disposed on a same corresponding one of the two sides as the second
mirror, and is positioned on a downstream sides the third mirror in
the traveling direction of the reflected light.
3. The image reading device according to claim 1, wherein, among
the plurality of mirrors, the mirrors other than a mirror
positioned on the most upstream side in the traveling direction of
the reflected light and a mirror positioned on the most downstream
side have the same length in the main scanning direction.
4. The image reading device according to claim 2, wherein, among
the mirrors having the same length in the main scanning direction,
concerning widths of the mirrors in a direction perpendicular to a
longitudinal direction of the mirrors, the width of a mirror
positioned on the most downstream side in the traveling direction
of the reflected light is greater than the widths of the other
mirrors.
5. The image reading device according to claim 1, wherein,
concerning positional relationships among the mirrors and the image
sensor as viewed from the main scanning direction, the mirrors
positioned on the corresponding one of the two sides and the image
sensor are disposed on the upstream side in an image reading
direction of a sub-scanning direction with respect to the imaginary
line, the image reading direction being a direction in which the
image of the document is read.
6. The image reading device according to claim 1, wherein,
concerning positional relationships among the mirrors as viewed
from the main scanning direction, the mirrors positioned on the
corresponding one of the two sides do not overlap the condenser
lens in a sub-scanning direction.
7. The image reading device according to claim 1, wherein: the
plurality of mirrors further include the third, fourth and fifth
mirrors, and the reflected light from the document is sequentially
reflected by the first, the third, fourth, the second and the fifth
mirrors and light reflected by the fifth mirror is guided to the
condenser lens; and the mirrors positioned on the corresponding one
of the two sides are the second and the third mirrors, and mirrors
positioned on the other one of the two sides are the fourth and the
fifth mirrors.
8. An image forming apparatus comprising: the image reading device
according to claim 1.
Description
BACKGROUND
1. Field
[0001] The present application is a divisional application of U.S.
patent application Ser. No. 16/218,189, filed on Dec. 12, 2018,
which claims priority to Japanese Patent Application No.
2017-253607 filed in Japan on Dec. 28, 2017. The entire disclosure
of such parent application is incorporated herein by reference.
[0002] The present disclosure relates to an image reading device
and an image forming apparatus, such as a copying machine, a
multifunction device, and a fax machine, including the image
reading device.
2. Description of the Related Art
[0003] An image reading device including the following type of
image reader is known (see Japanese Unexamined Patent Application
Publication Nos. H5-30293 and H7-56242, for example). The image
reader scans a document so as to read an image of the document by
using an image sensor via plural mirrors and a condenser lens.
[0004] In the image readers of the image reading devices disclosed
in the above-described publications, light reflected by a document
is reflected multiple times by using one mirror. This configuration
disturbs the balance of the arrangement of plural mirrors. This
also varies the optical path lengths among the mirrors, thereby
failing to arrange the plural mirrors in a well-balanced manner.
The size of the image readers is thus increased, which also makes
the image reading devices larger.
[0005] It is thus desirable to arrange plural mirrors in a
well-balanced manner so as to reduce the size of an image reader
and also the sizes of an image reading device and an image forming
apparatus including the image reading device.
SUMMARY
[0006] According to an aspect of the disclosure, there is provided
an image reading device including an image reader that scans a
document so as to read an image of the document. The image reader
includes a scanning body in which at least a plurality of mirrors,
a condenser lens, and an image sensor are disposed. In the scanning
body, concerning positional relationships among the plurality of
mirrors as viewed from a main scanning direction, the plurality of
mirrors are disposed on two sides with respect to an imaginary line
extending along an optical axis of reflected light from the
document. A plurality of the mirrors on a corresponding one of the
two sides are disposed such that a reflecting position of a mirror
on a downstream side in a traveling direction of the reflected
light is positioned closer to the document and also to the
imaginary line than a reflecting position of a mirror on an
upstream side in the traveling direction of the reflected light.
According to another aspect of the disclosure, there is provided an
image forming apparatus including the above-described image reading
device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic front sectional view of an image
forming apparatus including an image reading device according to an
embodiment of the disclosure;
[0008] FIG. 2 is a schematic front sectional view of an image
reader included in the image reading device;
[0009] FIG. 3 is a front perspective view of the image reader
without a light source unit as viewed from obliquely upward;
[0010] FIG. 4 is a plan view of the image reader without the light
source unit as viewed from above; and
[0011] FIG. 5 is a schematic view of a reduction-type optical
system in the image reading device.
DESCRIPTION OF THE EMBODIMENTS
[0012] An embodiment of the disclosure will be described below with
reference to the accompanying drawings. In the following
description, components having the same name and the same function
are designated by like reference numerals, and thus, a detailed
explanation thereof will not be repeated.
[Image Forming Apparatus]
[0013] FIG. 1 is a schematic front sectional view of an image
forming apparatus 100 including an image reading device 200
according to an embodiment of the present disclosure. In FIG. 1,
the symbols X indicate the main scanning direction. The
double-headed arrow Y indicates the sub-scanning direction
perpendicular to the main scanning direction X, and the arrow Y1
indicates the direction in which a document G is read (also be
simply called the image reading direction Y1). The double-headed
arrow Z indicates the top-bottom direction and the vertical
direction. The image forming apparatus 100 according to the present
embodiment is a monochrome image forming apparatus. The image
forming apparatus 100 performs image forming processing in
accordance with image data read by the image reading device 200 or
image data transferred from an external source. The image forming
apparatus 100 may alternatively be a color image forming apparatus
that forms a multicolor or single-color image on a sheet P.
[0014] The image forming apparatus 100 includes a document feeder
108 and a body 110 of the image forming apparatus 100. The body 110
includes an image forming system 102 and a sheet transport system
103.
[0015] The image forming system 102 includes an exposure unit 1, a
developing unit 2, a photoconductor drum 3 which serves as an
electrostatic latent image carrier, a cleaning unit 4, a charger 5,
and a fixing unit 7. The sheet transport system 103 includes a
sheet feeder tray 81, a manual sheet feeder tray 82, a discharge
roller 31, and a discharge tray 14.
[0016] The image reading device 200 for reading an image of the
document G is provided on the top of the body 110. The image
reading device 200 includes a document table 221 (more
specifically, document glass) on which the document G is placed and
a document reading plate 222 (more specifically, document reading
glass). The document feeder 108 is provided above the document
table 221 and the document reading plate 222. In the image forming
apparatus 100, the image of the document G read by the image
reading device 200 is supplied to the body 110 as image data and is
recorded on a sheet P.
[0017] A sheet transport path W1 is provided in the body 110. The
sheet feeder tray 81 or the manual sheet feeder tray 82 feeds a
sheet P to the sheet transport path W1. The sheet transport path W1
guides the sheet P to the discharge tray 14 via a transfer roller
10 and the fixing unit 7. The fixing unit 7 heats a toner image
formed on the sheet P and fixes it on the sheet P. In the vicinity
of the sheet transport path W1, pickup rollers 11a and 11b, a
transport roller 12a, a registration roller 13, the transfer roller
10, a heat roller 71 and a pressure roller 72 in the fixing unit 7,
and the discharge roller 31 are disposed.
[0018] In the image forming apparatus 100, the sheet P fed by the
sheet feeder tray 81 or the manual sheet feeder tray 82 is
transported to the registration roller 13. Then, the sheet P is
transported to the transfer roller 10 by the registration roller 13
at a timing at which the sheet P will face the toner image formed
on the photoconductor drum 3. The toner image is then transferred
to the sheet P by the transfer roller 10. Thereafter, the sheet P
passes between the heat roller 71 and the pressure roller 72 of the
fixing unit 7 and is discharged to the discharge tray 14 via the
transport roller 12a and the discharge roller 31. If an image is
formed on the back side of the sheet P as well as on the front
side, the sheet P is transported back to a reverse sheet transport
path W2 from the discharge roller 31 in the reverse direction.
After the sheet P is turned over from the front side to the back
side via reverse transport rollers 12b, it is supplied again to the
registration roller 13. A toner image is transferred to the back
side of the sheet P and is fixed on the sheet P, as in the front
side, and then, the sheet P is discharged to the discharge tray
14.
[Image Reading Device]
[0019] The image reading device 200 includes an image reader 300
(more specifically, an image reading unit) that scans a document G
so as to read the image of the document G. The image reading device
200 scans the document G placed on the document table 221 while
moving the image reader 300 along the bottom surface of the
document table 221 in the image reading direction Y1 of the
scanning direction Y. In this manner, the image reading device 200
reads the image of the document G placed on the document table 221
by using a reduction-type image sensor 340 (an example of an image
sensor). Additionally, the image reading device 200 stops the image
reader 300 at a position under the document reading plate 222 and
causes the image reader 300 to scan a document G transported by the
document feeder 108 and passing on the document reading plate 222.
In this manner, by using the reduction-type image sensor 340, the
image reading device 200 reads the image of the document G
transported by the image feeder 108.
[0020] The image reader 300 is provided to be reciprocatable under
the document table 221 and the document reading plate 222 within a
housing 201 of the image reading device 200 in the sub-scanning
direction Y. The image reader 300 is driven by a driver, which is
not shown.
[Image Reader]
[0021] FIG. 2 is a schematic front sectional view of the image
reader 300 included in the image reading device 200. FIG. 3 is a
front perspective view of the image reader 300 without a light
source unit 310 as viewed from obliquely upward. FIG. 4 is a plan
view of the image reader 300 without the light source unit 310 as
viewed from above. FIG. 5 is a schematic view of a reduction-type
optical system in the image reading device 200. In FIG. 5, first
through fifth mirrors 321 through 325 with the mirror surfaces
facing upward are shown. In FIG. 5, a indicates the reading
effective width.
[0022] In the image reader 300, at least plural mirrors 320, a
condenser lens 330, and the reduction-type image sensor 340 are
provided. The image reader 300 reads an image by using the
reduction-type image sensor 340 via the plural mirrors 320 and the
condenser lens 330. The image reader 300 includes the light source
unit 310 (see FIG. 2), the plural mirrors 320, the condenser lens
330, the reduction-type image sensor 340, and a housing 350 (an
example of a scanning body).
[0023] The light source unit 310 illuminates the document G. The
light source unit 310 includes a pair of light sources 311 and a
pair of reflection members 312. The light sources 311 oppose the
document G. The light sources 311 are disposed at different
positions in the sub-scanning direction Y and are disposed on the
respective reflection members 312. The reflection members 312
reflect light from the light sources 311 and apply it to the
document G. The reflection members 312 are disposed on the top
surface of the housing 350.
[0024] The plural mirrors 320 are constituted by the first through
fifth mirrors 321 through 325 in this example. Reflected light L
from the document G is sequentially reflected by the first through
fifth mirrors 321 through 325 and the light reflected by the fifth
mirror 325 is guided to the condenser lens 330.
[0025] In the housing 350, concerning the positional relationships
among the plural mirrors 320 as viewed from the main scanning
direction X, the plural mirrors 320 are disposed on two sides S1
and S2 with respect to an imaginary line Q extending along the
optical axis of the reflected light L from the document G. More
specifically, concerning the positional relationships among the
plural mirrors 320 (first through fifth mirrors 321 through 325) as
viewed from the main scanning direction X, the mirrors (second
through fifth mirrors 322 through 325) other than the first mirror
321 which reflects the reflected light L from the document G are
disposed on the two sides S1 and S2 in the following manner. Among
the mirrors (second through fifth mirrors 322 through 325), the
mirrors disposed on the side S1 and those disposed on the side S2
with respect to the imaginary line Q are the same number or
substantially the same number. For example, if the number of
mirrors (second through fifth mirrors 322 through 325) other than
the first mirror 321 is an odd number, one more mirror can be
disposed on one of the two sides S1 and S2.
[0026] The condenser lens 330 concentrates and condenses the
reflected light L from the fifth mirror 325 to the reduction-type
image sensor 340. The reduction-type image sensor 340 converts the
reflected light L from the condenser lens 330 into an electric
signal. As the reduction-type image sensor 340, a sensor including
an imaging element, such as a charge-coupled device (CCD) or a
complementary metal-oxide semiconductor (CMOS), may be used.
[0027] Concerning the positional relationships among the plural
mirrors 320 as viewed from the main scanning direction X, the
plural mirrors on one of the sides S1 and S2 (second and fourth
mirrors 322 and 324 on the side S1 in this example) are arranged in
the following manner. The reflecting position of the mirror on the
downstream side (fourth mirror 324 in this example) in the
traveling direction E of the reflected light L is positioned closer
to the document G and also to the imaginary line Q than the mirror
on the upstream side (second mirror 322 in this example). This
makes it possible to arrange the mirrors (second through fifth
mirrors 322 through 325) other than the first mirror 321 in a
well-balanced manner. With this arrangement, the size of the image
reader 300 can be reduced, which also makes the image reading
device 200 smaller. Additionally, the phenomenon where the
reflected light L is blocked by the condenser lens 300 (vignetting)
can effectively be prevented. To put it more precisely, the first
through fifth mirrors 321 through 325 can be arranged in a
well-balanced manner. It is thus possible to reduce the size of the
image reader 300 using five mirrors.
[0028] The mirrors on the other side (third and fifth mirrors 323
and 325 on the side S2 in this example) are arranged such that the
reflecting positions of the mirrors are aligned or substantially
aligned in parallel with the imaginary line Q. This makes it
possible to arrange the mirrors 320 (first through fifth mirrors
321 through 325) in an even better-balanced manner. The size of the
image reader 300 can further be reduced.
First Embodiment
[0029] In the reduction-type optical system, as shown in FIG. 5,
the width in the main scanning direction X of the reflected light L
from the document G becomes narrower as the reflected light L is
separated farther from the document G. It is thus possible to make
the lengths D1 through D5 (D) in the main scanning direction X of
the plural mirrors 320 (first through fifth mirrors 321 through
325) shorter as the mirror is separated farther from the document
G. However, when the housing 350 of the image reader 300 is formed
with a mold, the following problem arises if, concerning the
positional relationships among the mirrors as viewed from the main
scanning direction X, the mirrors (fourth and third mirrors 324 and
323) closer to the document G overlap the mirrors (second and fifth
mirrors 322 and 325) separated from the document G in the
sub-scanning direction Y, as shown in FIG. 2. If the lengths D4 and
D3 (D) in the main scanning direction X of the mirrors (fourth and
third mirrors 324 and 323) closer to the document G are shorter
than the lengths D2 and D5 (D) in the main scanning direction X of
the mirrors (second and fifth mirrors 322 and 325) separated from
the document G, undercuts are formed in the housing 350 and a
certain undercut process may be required when forming the housing
350 with a mold.
[0030] In the present embodiment, among the plural mirrors 320
(first through fifth mirrors 321 through 325), the second through
fourth mirrors 322 through 324 other than the first mirror 321
positioned on the most upstream side (closest to the document G) in
the traveling direction E of the reflected light L and the fifth
mirror 325 positioned on the most downstream side (closest to the
condenser lens 330) have the same length in the main scanning
direction X (see FIG. 5). This avoids the formation of undercuts in
the housing 350. Additionally, the same mirror can be used for the
mirrors other than the first and fifth mirrors 321 and 325. In the
first embodiment, concerning the positional relationship between
the fourth mirror 324 and the second mirror 322 as viewed from the
main scanning direction X, the fourth mirror 324 closer to the
document G overlaps the second mirror 322 separated from the
document G in the sub-scanning direction Y. However, the lengths D2
and D4 of the second and fourth mirrors 322 and 324 in the main
scanning direction X are equal to each other. Likewise, concerning
the positional relationship between the third mirror 323 and the
fifth mirror 325 as viewed from the main scanning direction X, the
third mirror 323 overlaps the fifth mirror 325 in the sub-scanning
direction Y. However, the length D3 of the third mirror 323 in the
main scanning direction X is longer than the length D5 of the fifth
mirror 325 in the main scanning direction X. Additionally,
concerning the positional relationships among the plural mirrors
320 as viewed from the main scanning direction X, the first mirror
321 does not overlap any of the second through fifth mirrors 322
through 325 in the sub-scanning direction Y. With the
above-described positional relationships among the mirrors 320,
undercuts are not formed in the housing 350.
[0031] In the first embodiment, the lengths D1 through D5 (D) of
the first through fifth mirrors 321 through 325 in the main
scanning direction X are about 215 mm, 175 mm, 175 mm, 175 mm, 54.6
mm, respectively. The thicknesses of the first through fifth
mirrors 321 through 325 are all about 3.8 mm.
Second Embodiment
[0032] In the reduction-type optical system, as shown in FIG. 2,
the width of the reflected light L from the document G in the
direction perpendicular to the longitudinal direction becomes wider
as the reflected light L is farther separated from the document G.
In the present embodiment, among the second through fourth mirrors
322 through 324 having the same length D2 through D4 in the main
scanning direction X, the width W4 (W) of the fourth mirror 324 on
the most downstream side (closest to the condenser lens 330) in the
traveling direction E of the reflected light L is greater than the
widths W2 and W3 (W) of the second and third mirrors 322 and 323
(see FIG. 5). It is thus possible to handle the reflected light G
which becomes wider as it is separated farther from the document
G.
[0033] In the second embodiment, the widths W1 through W5 (W) of
the first through fifth mirrors 321 through 325 are about 7 mm, 7
mm, 7 mm, 9 mm, and 10 mm, respectively. The same mirror can be
used for the second and third mirrors 322 and 323.
Third Embodiment
[0034] In the present embodiment, concerning the positional
relationships among the mirrors and the reduction-type image sensor
340 as viewed from the main scanning direction X, the second and
fourth mirrors 322 and 324 located on the side S1 and the
reduction-type image sensor 340 are disposed on the upstream side
in the image reading direction Y1 of the sub-scanning direction Y
with respect to the imaginary line Q. With this configuration,
fewer components (parts) can be disposed on the downstream side
(side S2) in the image reading direction Y1 with respect to the
imaginary line Q. This can reduce the size of the housing 350 in
the sub-scanning direction Y on the downstream side (side S2). This
can also reduce the size of the image reading device 200 in the
image reading direction Y1 without decreasing the moving region of
the image reader 300 in the sub-scanning direction Y.
Fourth Embodiment
[0035] In the present embodiment, concerning the positional
relationship between the second and fourth mirrors 322 and 324 and
the condenser lens 330 as viewed from the main scanning direction
X, the second and fourth mirrors 322 and 324 disposed on the side
S1 do not overlap the condenser lens 330 in the sub-scanning
direction Y. Hence, the plural mirrors 320 (first through fifth
mirrors 321 through 325) can be arranged in an even better-balanced
manner, thereby making it possible to further reduce the size of
the image reader 300.
Other Embodiments
[0036] In the present embodiment, five mirrors are used. However,
more than or fewer than five mirrors may be used.
[0037] The present disclosure contains subject matter related to
that disclosed in Japanese Priority Patent Application JP
2017-253607 filed in the Japan Patent Office on Dec. 28, 2017, the
entire contents of which are hereby incorporated by reference.
[0038] The present disclosure is not restricted to the
above-described embodiments and may be embodied in other forms. The
embodiments are therefore to be considered in all respects as
illustrative and not restrictive. It should be understood by those
skilled in the art that various modifications, combinations,
sub-combinations and alterations may occur depending on design
requirements and other factors insofar as they are within the scope
of the appended claims or the equivalents thereof. The scope of the
disclosure is indicated by the appended claims and all changes
which come within the meaning and range of equivalency of the
claims are intended to be embraced therein.
* * * * *