U.S. patent application number 09/766268 was filed with the patent office on 2001-08-23 for document feeding apparatus and image forming apparatus.
Invention is credited to Endo, Satoru, Fujita, Junichi, Hirota, Kazuhiro, Ito, Kazuaki, Kato, Nobutaka, Kato, Osamu.
Application Number | 20010016133 09/766268 |
Document ID | / |
Family ID | 18543449 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010016133 |
Kind Code |
A1 |
Hirota, Kazuhiro ; et
al. |
August 23, 2001 |
Document feeding apparatus and image forming apparatus
Abstract
An apparatus for feeding a both-sided document having images on
both sides thereof is provided with a document stand; a reading
section; a feeder having a feeding passage and to feed the
both-sided document from the document stand to the reading section
along the feeding passage; a pair of reversing rollers provided on
a reversing passage to reverse the both-sided document after an
image of the both-sided document is read at the reading section and
to reefed the reversed both-sided document from the reversing
passage to the feeding passage so that an image on another side of
the both-sided document is read at the reading section; a pair of
ejecting rollers provided on an ejecting passage and to eject the
both-sided document to a delivery section after the images on both
sides of the both-sided document are read at the reading section;
and a switching mechanism to connect an outlet passage of the
reading section to one of the reversing passage and the ejecting
passage; wherein one of the pair of reversing rollers and one of
the ejecting rollers are mounted coaxially on a shaft.
Inventors: |
Hirota, Kazuhiro; (Tokyo,
JP) ; Fujita, Junichi; (Tokyo, JP) ; Endo,
Satoru; (Tokyo, JP) ; Ito, Kazuaki;
(Kawagoe-shi, JP) ; Kato, Nobutaka; (Tokyo,
JP) ; Kato, Osamu; (Tokyo, JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN &
LANGER & CHICK, PC
767 THIRD AVENUE
25TH AVE
NEW YORK
NY
10017-2023
US
|
Family ID: |
18543449 |
Appl. No.: |
09/766268 |
Filed: |
January 19, 2001 |
Current U.S.
Class: |
399/374 ;
358/474; 399/367 |
Current CPC
Class: |
H04N 1/00655 20130101;
H04N 1/00572 20130101; H04N 1/0058 20130101; H04N 1/00602 20130101;
G03G 15/60 20130101; G03G 2215/00316 20130101; H04N 1/00631
20130101; H04N 1/00578 20130101 |
Class at
Publication: |
399/374 ;
399/367; 358/474 |
International
Class: |
G03G 015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 25, 2000 |
JP |
016291/2000 |
Claims
What is claimed is:
1. An apparatus for feeding a both-sided document having images on
both sides thereof, comprising: a document stand on which the
both-sided document is placed; a reading section at which an image
of the both-sided document is read by an image reader; a feeder
having a feeding passage and to feed the both-sided document from
the document stand to the reading section along the feeding
passage; a pair of reversing rollers provided on a reversing
passage to reverse the both-sided document after an image of the
both-sided document is read at the reading section and to reefed
the reversed both-sided document from the reversing passage to the
feeding passage so that an image on another side of the both-sided
document is read at the reading section; a pair of ejecting rollers
provided on an ejecting passage and to eject the both-sided
document to a delivery section after the images on both sides of
the both-sided document are read at the reading section; and a
switching mechanism to connect an outlet passage of the reading
section to one of the reversing passage and the ejecting passage;
wherein one of the pair of reversing rollers and one of the
ejecting rollers are mounted coaxially on a shaft.
2. The apparatus of claim 1, wherein the pair of reversing rollers
comprises a reversing driving-roller and a reversing driven-roller
and the pair of ejecting rollers comprises an ejecting
driving-roller and an ejecting driven-roller, and wherein one of
the reversing driving-roller and the ejecting driving-roller and
one of the reversing driven-roller and the ejecting driven-roller
are mounted coaxially on the shaft.
3. The apparatus of claim 2, wherein the ejecting driving-roller
and the reversing driven-roller are mounted coaxially on the
shaft.
4. The apparatus of claim 1, wherein the switching mechanism
comprises a switching gate swinging around a fulcrum thereof and
the fulcrum of the switching gate provided coaxially on the
shaft.
5. The apparatus of claim 1, further comprising: a pair of reading
section outlet rollers provided between the reading section and the
switching mechanism, the pair of reading section outlet rollers
including an outlet upper roller and an outlet lower roller; an
upper guide provided to the outlet upper roller; and an lower guide
provide to the outlet lower roller; wherein the upper guide and the
lower guide leads the both-sided document from the reading section
to the switching mechanism.
6. The apparatus of claim 5, wherein the outlet upper roller and
the outlet lower roller are brought in pressure contact with each
other by a ring-shaped spring.
7. The apparatus of claim 1, wherein the reversing passage
comprises a curved bent section having a curved concave section and
a fixed guide member provided at the curved concave portion of the
curved bent section.
8. The apparatus of claim 1, wherein the reversing passage
comprises a curved bent section having a curved convex portion and
a roller provided at the curved convex portion of the curved bent
section.
9. An image forming apparatus, comprising: an image reader to read
an image on a document; a recording device to record an image on a
recording sheet based on the image read by the image reader; and a
document conveying device to convey a both-sided document to the
image reader in such a way that images on the both-sided document
are read by the image reader, the document conveying device
comprising document stand on which the both-sided document is
placed; a reading section at which an image of the both-sided
document is read by the image reader; a feeder having a feeding
passage and to feed the both-sided document from the document stand
to the reading section along the feeding passage; a pair of
reversing rollers provided on a reversing passage to reverse the
both-sided document after an image of the both-sided document is
read at the reading section and to reefed the reversed both-sided
document from the reversing passage to the feeding passage so that
an image on another side of the both-sided document is read at the
reading section; a pair of ejecting rollers provided on an ejecting
passage and to eject the both-sided document to a delivery section
after the images on both sides of the both-sided document are read
at the reading section; and a switching mechanism to connect an
outlet passage of the reading section to one of the reversing
passage and the ejecting passage; wherein one of the pair of
reversing rollers and one of the ejecting rollers are mounted
coaxially on a shaft.
10. The image forming apparatus of claim 9, wherein the pair of
reversing rollers comprises a reversing driving-roller and a
reversing driven-roller and the pair of ejecting rollers comprises
an ejecting driving-roller and an ejecting driven-roller, and
wherein one of the reversing driving-roller and the ejecting
driving-roller and one of the reversing driven-roller and the
ejecting driven-roller are mounted coaxially on the shaft.
11. The image forming apparatus of claim 10, wherein the ejecting
driving-roller and the reversing driven-roller are mounted
coaxially on the shaft.
12. The image forming apparatus of claim 9, wherein the image
reader comprises an optical system fixed to be stationary so that
the image of the both-sided document is read though the optical
system while the both-sided document is fed by the feeder.
13. The apparatus of claim 9, wherein the switching mechanism
comprises a switching gate swinging around a fulcrum thereof and
the fulcrum of the switching gate provided coaxially on the
shaft.
14. The apparatus of claim 9, further comprising: a pair of reading
section outlet rollers provided between the reading section and the
switching mechanism, the pair of reading section outlet rollers
including an outlet upper roller and an outlet lower roller; an
upper guide provided to the outlet upper roller; and an lower guide
provide to the outlet lower roller; wherein the upper guide and the
lower guide leads the both-sided document from the reading section
to the switching mechanism.
15. The apparatus of claim 14, wherein the outlet upper roller and
the outlet lower roller are brought in pressure contact with each
other by a ring-shaped spring.
16. The apparatus of claim 9, wherein the reversing passage
comprises a curved bent section having a curved concave section and
a fixed guide member provided at the curved concave portion of the
curved bent section.
17. The apparatus of claim 9, wherein the reversing passage
comprises a curved bent section having a curved convex portion and
a roller provided at the curved convex portion of the curved bent
section.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a document feeding apparatus which
enables image reading by feeding an original document in order to
form an image by an image forming apparatus such as an
electrophotographic copying machine, a printer, a facsimile
machine, a compound machine having these plural functions, or a
printing machine, and to an image forming apparatus.
[0002] Some of document feeding apparatus provided in such an image
forming apparatus of a digital type separate to feed a single sheet
from the other document sheets stacked on the sheet feeding tray,
and are capable of reading the both sides of the document by
switching over the pathway between the ejecting passage and the
reversing passage.
[0003] In such a document feeding apparatus, the reversing rollers
and the ejecting rollers are arranged separately in the up-and-down
direction, therefore, the document feeding apparatus is made
large-sized in the height direction. Further, because the switching
gate for switching over the pathway between the ejecting passage
and the reversing passage is disposed at the upstream side of the
reversing rollers and the ejecting rollers, the document feeding
apparatus is made large-sized in the width direction.
[0004] In the reversing passage, a document sheet is conveyed in
direct contact with the guide ribs forming the reversing passage,
therefore, the resistance to conveyance is large, and the document
sheet skews, often to cause a paper jam to occur.
[0005] Further, a pair of ejecting rollers for ejecting a document
sheet after being read and an ejected sheet guide member for
guiding the document sheet to be ejected are provided, but the
ejecting rollers and the ejection guide members are mounted
separately; therefore, the document feeding apparatus is made
large-sized.
SUMMARY OF THE INVENTION
[0006] This invention has been made in view of the above-mentioned
points; it is an object of the invention to provide a document
feeding apparatus and an image forming apparatus, which make it
possible to make its size smaller by employing a part for common
use to plural members and reducing the number of parts, and also
make it possible to raise the document conveying ability.
[0007] In order to solve the above-mentioned problems and to
accomplish the object, this invention is made to have any one of
the following structures.
[0008] An apparatus for feeding a both-sided document having images
on both sides thereof, comprises:
[0009] a document stand on which the both-sided document is
placed;
[0010] a reading section at which an image of the both-sided
document is read by an image reader;
[0011] a feeder having a feeding passage and to feed the both-sided
document from the document stand to the reading section along the
feeding passage;
[0012] a pair of reversing rollers provided on a reversing passage
to reverse the both-sided document after an image of the both-sided
document is read at the reading section and to reefed the reversed
both-sided document from the reversing passage to the feeding
passage so that an image on another side of the both-sided document
is read at the reading section;
[0013] a pair of ejecting rollers provided on an ejecting passage
and to eject the both-sided document to a delivery section after
the images on both sides of the both-sided document are read at the
reading section; and
[0014] a switching mechanism to connect an outlet passage of the
reading section to one of the reversing passage and the ejecting
passage;
[0015] wherein one of the pair of reversing rollers and one of the
ejecting rollers are mounted coaxially on a shaft.
[0016] An image forming apparatus, comprises:
[0017] an image reader to read an image on a document;
[0018] a recording device to record an image on a recording sheet
based on the image read by the image reader; and
[0019] a document conveying device to convey a both-sided document
to the image reader in such a way that images on the both-sided
document are read by the image reader,
[0020] the document conveying device comprising
[0021] a document stand on which the both-sided document is
placed;
[0022] a reading section at which an image of the both-sided
document is read by the image reader;
[0023] a feeder having a feeding passage and to feed the both-sided
document from the document stand to the reading section along the
feeding passage;
[0024] a pair of reversing rollers provided on a reversing passage
to reverse the both-sided document after an image of the both-sided
document is read at the reading section and to reefed the reversed
both-sided document from the reversing passage to the feeding
passage so that an image on another side of the both-sided document
is read at the reading section;
[0025] a pair of ejecting rollers provided on an ejecting passage
and to eject the both-sided document to a delivery section after
the images on both sides of the both-sided document are read at the
reading section; and
[0026] a switching mechanism to connect an outlet passage of the
reading section to one of the reversing passage and the ejecting
passage;
[0027] wherein one of the pair of reversing rollers and one of the
ejecting rollers are mounted coaxially on a shaft.
[0028] Further, the above object may be attained by the following
preferable structures.
[0029] (1) A document feeding apparatus, which separates to feed a
single sheet from the other document sheets stacked on a sheet
feeding tray (document stand) and are capable of reading the both
sides of a document sheet, comprising
[0030] a document reading section arranged in the lower part and a
reversing passage and a pair of reversing rollers for reading the
both sides of the document sheet arranged in the upper part,
[0031] an ejecting passage and a pair of ejecting rollers arranged
at the downstream side of said document reading section, and
[0032] a switching gate for switching over the pathway from said
document reading section between said reversing passage and said
ejecting passage, wherein
[0033] the driven one of said pair of reversing rollers and the
driving one of said pair of ejecting rollers are arranged on the
same shaft.
[0034] According to the invention described in the structure (1),
the driven one of the pair of reversing rollers and the driving one
of the pair of ejecting rollers are disposed on the same shaft;
therefore, the number of parts is made smaller, and it is possible
to make the size in the height direction smaller.
[0035] (2) A document feeding apparatus as set forth in the
structure (1), wherein the supporting point (fulcrum) of the
aforesaid switching gate is provided on the aforesaid shaft.
[0036] According to the invention described in the structure (2),
the supporting point of the switching gate is provided on the shaft
on which the driven one of the pair of reversing rollers and the
driving one of the pair of ejecting rollers are provided;
therefore, the number of parts is made smaller, and it is possible
to make smaller the size in the width direction, on top of the
height direction.
[0037] (3) A document feeding apparatus, which separates to feed a
single sheet from the other document sheets stacked on a sheet
feeding tray, is provided with a reversing passage for reading the
both sides of a document sheet, and are capable of reading the both
sides of the document sheet, wherein
[0038] a conveyance-resistance reducing rolling bar for reducing
the resistance to conveyance of a document sheet is attached in
said reversing passage.
[0039] According to the invention described in the structure (3),
the resistance to conveyance of a document sheet in the reversing
passage can be reduced by the conveyance-resistance reducing
rolling bar; therefore, the conveying ability for a document is
improved, and it becomes possible to reduce the frequency of the
occurrence of a paper jam.
[0040] (4) A document feeding apparatus as set forth in the
structure (3), wherein the aforesaid reversing passage bends in the
shape of S, and at least in a part of the bending portions (curved
bent portions), the aforesaid conveyance-resistance reducing
rolling bar is disposed.
[0041] According to the invention described in the structure (4),
the reversing passage is s-shaped, and the conveyance-resistance
reducing rolling bar is disposed in the bending portion; therefore,
the apparatus is made compact, and the document conveying ability
in the bending portion is improved, to make it possible to reduce
the frequency of the occurrence of a paper jam.
[0042] (5) A document feeding apparatus as set forth in the
structure (3) or (4), wherein a plurality of the aforesaid
conveyance-resistance reducing rolling bars are provided between
the guide ribs forming the aforesaid reversing passage.
[0043] According to the invention described in the structure (5), a
plurality of the aforesaid conveyance-resistance reducing rolling
bars are provided between the guide ribs forming the aforesaid
reversing passage; therefore, the apparatus is made compact, and
the document conveying ability is improved, to make it possible to
reduce the frequency of the occurrence of a paper jam.
[0044] (6) A document feeding apparatus as set forth in any one of
the structures (3) to (5), wherein the aforesaid
conveyance-resistance reducing rolling bar is provided in such a
way that only a part of it is projected out of the aforesaid guide
ribs toward the reversing passage in order that a document sheet
may hit a portion of the rolling bar deviated to the sheet passing
side from the central line.
[0045] According to the invention described in the structure (6),
the conveyance-resistance reducing rolling bar is provided in such
a way that only a part of it is projected out of the guide ribs
toward the reversing passage side and a document sheet hits a
portion of the rolling bar deviated to the sheet passing side from
the central line; therefore, the apparatus is made compact, and the
document conveying ability is improved.
[0046] (7) A document feeding apparatus, which separates to feed a
single sheet from the other document sheets stacked on a sheet
feeding tray and are capable of reading the both sides of a
document sheet, comprising
[0047] a pair of outlet rollers for ejecting said document sheet
after said document sheet is read and an outlet guide member for
guiding a document sheet to be ejected, wherein
[0048] the shaft of one of said pair of outlet rollers is used also
as the mounting portion for said outlet guide member.
[0049] According to the invention described in the structure (7),
the shaft of one of the pair of outlet rollers is used also as the
mounting portion for the outlet guide member; therefore, the number
of parts is made smaller, and it is possible to make the size
smaller.
[0050] (8) A document feeding apparatus as set forth in the
structure (7), wherein the driving one and the driven one of the
aforesaid pair of outlet rollers are pressed to each other by a
ring-shaped spring.
[0051] According to the invention described in the structure (8),
the driving one and the driven one of the aforesaid pair of outlet
rollers are pressed to each other by a ring-shaped spring;
therefore, the pair of ejecting rollers are made to form a compact
unit.
[0052] (9) An image forming apparatus provided with a document
feeding apparatus as set forth in any one of the structures (1) to
(8).
[0053] According to the invention described in the structure (9),
the image forming apparatus can be provided with a document feeding
apparatus, which makes it possible to make its size smaller by
employing a part for common use to plural members and reducing the
number of parts, and also make it possible to raise the document
conveying ability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] FIG. 1 is a drawing showing the overall structure of an
image forming apparatus provided with an print sheet finishing
apparatus, a document feeding apparatus, and an image reading
apparatus;
[0055] FIG. 2 is a cross-sectional view of a document feeding
apparatus;
[0056] FIG. 3 is the plan of a document feeding apparatus;
[0057] FIG. 4 is the front view of the reversing-ejecting unit;
[0058] FIG. 5 is an enlarged cross-sectional view of the conveyance
section;
[0059] FIG. 6 is the rear view of the paper feed driving motor
section;
[0060] FIG. 7 is the rear view of the reversible driving motor
section;
[0061] FIG. 8 is an enlarged drawing of the reversing passage;
and
[0062] FIG. 9 is the front view of the conveyance-resistance
reducing rolling bars.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0063] In the following, an embodiment of an image forming
apparatus provided with a document feeding apparatus of this
invention will be explained on the basis of the drawings; however,
this invention is not to be limited to this embodiment.
[0064] FIG. 1 is a drawing showing the overall structure of the
image forming apparatus 1 equipped with the print sheet finishing
apparatus FS, the document feeding apparatus DF, and the image
reading apparatus (scanner) SC.
[0065] The image forming apparatus mainframe 1A shown in the
drawing is provided with the image processing section 2, the image
writing section 3, the image forming section 4, the high-voltage
power source section 5, the cassette sheet feeding section 6, the
fixing section 7, the sheet ejection section 8, and the
re-conveyance means (ADU) 9 for automatic duplex copying.
[0066] On the upper side of the image forming apparatus mainframe
1A, the image reading apparatus SC and the document feeding
apparatus DF are installed. To the upper left side, the side of the
sheet ejection section 8, of the image forming apparatus mainframe
1A, the print sheet finishing apparatus FS is connected.
[0067] The document sheet d, which is set on the document base of
the document feeding apparatus DF with the first side made to face
up, is conveyed to the direction of the arrow mark, and the image
of the one or both sides of the document is read by the CCD image
sensor C1 through the optical system of the image reading apparatus
SC.
[0068] The analogue signal obtained by the photoelectric conversion
by the CCD image sensor C1 is subjected to analogue processing, A/D
conversion, shading correction, image compression processing, etc.,
and then it is transmitted to the image writing section 3.
[0069] In the image writing section 3, the output light beam from a
semiconductor laser is applied to the photoreceptor drum 4A of the
image forming section 4, to form a latent image. In the image
forming section 4, the processes such as charging, exposure,
development, transfer, detachment, and cleaning are carried out,
and the image is transferred to the paper sheet S, which has been
conveyed from the cassette sheet feeding section 6. The paper sheet
S carrying an image is subjected to fixing in the fixing apparatus
7, and is conveyed from the sheet ejection section 8 to the print
sheet finishing apparatus FS. In other way, the paper sheet S
having an image on one side processed, which has been fed to the
re-conveyance means 9 by the ejecting passage switching plate 8A,
is subjected to duplex image processing in the image forming
section 4 again, and then, it is fed to the print sheet finishing
apparatus FS by the ejecting rollers 8B of the sheet ejection
section 8.
[0070] The print sheet finishing apparatus FS is mounted to the
upper left portion of the image forming apparatus mainframe 1A in a
manner capable of being mounted and dismounted. The print sheet
finishing apparatus SF is composed of the sheet conveyance means
10, the sheet ejection means 20, the after-print processing means
30, and the up-and-down moving ejection means 40, which are
arranged in the print sheet finishing apparatus mainframe 100.
[0071] In FIG. 1, in the right side inside the image forming
apparatus mainframe 1A, with respect to the image forming section 4
positioned at the center, in the lower part of the image forming
apparatus mainframe 1A in the height direction, there is provided
the cassette sheet feeding section 6, and in the upper part of it,
there are provided the fixing apparatus 7 and the sheet ejection
section 8. By this structure of vertical arrangement, the sheet
conveying passage (1) in the almost vertical direction is formed.
The paper sheet S, which has been conveyed out from the cassette
sheet feeding section 6, is conveyed along this upward-directing
sheet conveying passage and ejected to the outside of the image
forming apparatus mainframe 1A.
[0072] Approximately parallel to this sheet conveying passage (1)
in the vertical direction, the sheet conveying passage (2) by the
re-conveyance means 9 is formed.
[0073] By forming the above-mentioned sheet conveying passages (1)
and (2) in the vertical direction, a sheet conveying passage having
the shortest length from the cassette sheet feeding section 6 to
the sheet ejection section 8 is made up.
[0074] The sheet conveyance means 10 of the print sheet finishing
apparatus SF is contained in the space portion above the image
forming apparatus mainframe 1A as shown in the drawing. The sheet
entrance portion 11 of the sheet conveyance means 10 is adjacent to
the ejecting rollers 8B of the sheet ejection section 8 of the
image forming apparatus mainframe 1A. Further, in this state of
mounting, in the space portion at the upper left part of the image
forming apparatus mainframe 1A shown in the drawing, the sheet
ejection means 20 and the after-print processing means 30 of the
print sheet finishing apparatus SF are contained. The up-and-down
moving ejection means 40 composed of the plural trays for ejected
sheets (also called bins) 41 and the up-and-down movement driving
means 42 is located at the left side of the after-print processing
means 30 shown in the drawing.
[0075] In the following, the document feeding apparatus will be
explained on the basis of FIG. 2 to FIG. 8. FIG. 2 is a
cross-sectional view of the document feeding apparatus, FIG. 3 is
the plan of the document feeding apparatus, FIG. 4 is the front
view of the reversing-ejection unit, FIG. 5 is an enlarged
cross-sectional view of the conveyance section, FIG. 6 is the rear
view of the sheet feed driving motor section, FIG. 7 is the rear
view of the reversible driving motor section, FIG. 8 is an enlarged
drawing of the reversing passage, and FIG. 9 is the front view of
the conveyance-resistance reducing rolling bars.
[0076] In the document feeding apparatus DF, the document feeding
section 200, the ejection section 300, and the conveyance section
400 are arranged.
[0077] The document feeding section 200 comprises the sheet feeding
tray 201, on which a plurality of sheets of a document can be set,
and in this sheet feeding tray 201, a pair of regulation plates 202
for positioning document sheets in the width direction are provided
in such a manner as to be able to move in the width direction.
Further, in the sheet feeding tray 201, a plurality of rib-shaped
projections 201a, 201b, 201c, and 201d are provided respectively at
the positions with a short distance from the positions where the
trailing edges of the document sheets of the pertinent sizes come,
to prevent that a document sheet is made to move back to the
upstream direction by stopping the sheet at the time of
feeding.
[0078] The ejection section 300 comprises the output tray 301, and
this output tray 301 is disposed at the position under the document
feeding section 200. Onto the output tray 301, it is ejected the
document sheet having been conveyed by the conveyance section 400
in such a way that the one side or the both sides are read.
[0079] In the conveyance section 400, there are provided the
feeding passage P1, the ejecting passage P2, and the reversing
passage P3; the switching-over between the ejecting passage P2 and
the reversing passage P3 is carried out by the switching gate 401,
and the switching-over between the feeding passage P1 and the
reversing passage P3 is carried out by the switching gate 402.
Here, the switching gate 401 can swing as indicated with an arrow
mark around the shaft 431 so that the switching gate 401 can lead
the document from a document reading section 409 to one of the
reversing passage P3 and the ejecting passage P2. In the case where
only one side of an original document is read, the document sheet
fed from the document feeding section 200 passes the feeding
passage P1 and is ejected to the ejection section 300 through the
ejecting passage P2 which is switched over by the switching gate
401.
[0080] Further, in the case where both sides of an original
document are read, the document sheet fed from the document feeding
section 200 is conveyed once from the feeding passage P1 to the
reversing passage P3 to reverse the document sheet, wherein the
pathway is switched over to the reversing passage P3 by the
switching gate 402, and the reversed document sheet is conveyed
again to the feeding passage P1 to which the pathway is switched
over by the switching gate 402; then the first side of the document
sheet is read at the document reading section 409. After the first
side of the document sheet is read, the document sheet is led to
the reversing passage P3 to which the pathway is switched over by
the switching gate 401. When the document sheet is fed again from
the reversing passage P3 to the feeding passage P1, the document
sheet is reversed. Then, the second side of the document is read at
the document reading section 409. Thereafter, the document sheet is
ejected to the ejection section 300 by the switching gate 402
through the ejecting passage P2.
[0081] In the feeding section, the movable pressing plate 403, the
pickup roller 499, the feeding roller 404, the double-feed
preventing roller 406, the driving registration roller 405a, and
the driven registration roller 405b are arranged. The movable
pressing plate 403 is moved upward to press the document sheets to
the pickup roller 499 when the document is fed, and the pickup
roller 499 leads the top sheet to the feeding roller 404; thus, the
document sheets are fed one by one by the feeding roller 404 and
the double-feed preventing roller 406. This document sheet is
conveyed by the driving of the feeding roller 404 to the driving
registration roller 405a and the driven registration roller 405b,
the skew of the fed sheet is corrected by the driving registration
roller 405a and the driven registration roller 405b, the timing is
adjusted by the retard roller 407, and the document sheet is fed to
the document reading section 409.
[0082] As shown in FIG. 6, the movable pressing plate 403, the
feeding roller 404, and the driving registration roller 405a are
driven by the sheet feed driving motor M1, and by the rotation of
this motor M1, the torque limiter 411 is driven through the belt
410; the up-and-down movement driving shaft 412 of this torque
limiter 411 is rotated to make the movable pressing plate 403 move
upward, and the up-and-down movement driving shaft 412 acts as the
supporting point for the movable pressing plate 403 to move up and
down. By the rotation of this sheet feed driving motor M1, the
pulleys 414 and 415 of the feeding roller 404 and the driving
registration roller 405a are rotated through the belt 413; however,
because the one-way clutches 418 and 419 are provided at the roller
shafts 416 and 417 of the feeding roller 404 and the driving
registration roller 405a respectively, when the sheet feed motor M1
rotates in the direction to make the movable pressing plate 403
move upward, it is prevented the reverse rotation to the feeding
direction of the feeding roller 404 and the driving registration
roller 405a. By the reverse rotation of the sheet feed driving
motor M1, the pulleys 414 and 415 of the feeding roller 404 and the
driving registration roller 405a are rotated through the belt 413,
to rotate the feeding roller 404 and the driving registration
roller 405a.
[0083] The document reading section 409 is located at the lower
side, and the reversing passage P3 and the pair of reversing
rollers 420 for reading both sides of a document, and the pair of
ejecting rollers 430 are arranged in the middle part of the
conveyance section 400. Further, at the downstream side of the
document reading section 409, the ejecting passage P2 and the
outlet roller unit 421 are disposed, in which the switching gate
401 for switching over the pathway from the document reading
section 409 between the ejecting passage P2 and the reversing
passage P3 is disposed.
[0084] The outlet roller unit 421 comprises the pair of outlet
rollers 423 and the outlet guide members 424. The pair of outlet
rollers 423 comprise the driving one 423a and the driven one 423b,
and the shafts are used also for the mounting of the outlet guide
members 424, which reduces the number of parts and makes it
possible to make the apparatus small-sized. Further, the driving
one and the driven one of the pair of outlet rollers 423 are
pressed to each other by the ring-shaped spring 425, which makes it
possible to make the pair of outlet rollers 423 a compact unit.
[0085] The pair of reversing rollers 420 comprises the driving one
420a and the driven one 420b, and the pair of ejecting rollers also
comprise the driving one 430a and the driven one 430b. The driven
one 420b of the pair of reversing rollers 420 and the driving one
430a of the pair of ejecting rollers 430 are arranged on the same
shaft 431, and the driven one 420b is mounted rotatably around the
common shaft 431. Further, the supporting point (fulcrum) of the
switching gate is also provided on the common shaft 431, which
makes the number of parts small.
[0086] The driven one 430b of the pair of ejecting rollers 430 is
provided rotatbly around the shaft 432 as shown in FIG. 4 and FIG.
5, this shaft 432 being supported by the ejection guide member 433,
and is disposed in the ribs 433a of the ejection guide member 433.
The driving one 420a of the pair of reversing rollers 420 is
mounted on the shaft 434.
[0087] As shown in FIG. 3 and FIG. 5, the shaft 434 is supported by
the shaft 436 through the supporting members 435, and the shaft 436
is rotated in the forward and reverse direction by the reversible
driving motor M2 shown in FIG. 7. The shaft 436 and the shaft 434
is connected by the drive belt 437, and the rotating force of the
shaft 436 is transmitted to the shaft 434 through the belt 437 to
rotate it in the forward and reverse direction.
[0088] The pair of reversing rollers 420 and the pair of ejecting
rollers 430 are arranged in the vertical direction, which makes the
apparatus small-sized in the height direction, and the supporting
point (fulcrum) of the switching gate 401 is provided on the common
shaft 431, which makes the apparatus small-sized in the width
direction.
[0089] Further, by the shaft 436, the double-feed preventing roller
406, which is provided to its right, is supported through the stay
member 450, and the supporting point of the driving side is also
the supporting point of the double-feed preventing roller 406,
which makes it unnecessary to provide two shafts as the shaft 436
for the supporting point of the two rollers and makes it possible
to reduce the size.
[0090] As shown in FIG. 7, regarding the reversing rollers 420 and
the switching gate 402, the normal rotation of the reversible
driving motor M2 rotates the pulley 452 through the belt 451, and
rotates the shaft 436. Linked to this motion, the cam shaft 453 of
the switching gate 402 is rotated, and the switching gate 402 is
made to operate by the cam 454, to switch over the pathway to the
reversing passage P3. The reverse rotation of the reversible
driving motor M2 rotates the shaft 436 in the reverse direction
through the belt 451, and linked to this motion, the cam shaft 453
of the switching gate 402 is rotated reversely, and the switching
gate 402 is made to operate by the cam 454, to switch over the
pathway to the feeding passage P1.
[0091] At the time of ejection, by-the driving of the reading motor
M3 shown by the double dot and dash line in FIG. 5, the driving one
430a of the pair of ejecting rollers 430 is rotated, and a document
sheet is ejected by the rotation of the driving one 430a and the
driven one 430b in the direction of ejection.
[0092] At the time of reversing, the rotation of the shaft 436 is
transmitted to the shaft 434 through the belt 437, and it is
further transmitted from the driving one of the pair 420a of
reversing rollers 420 to its driven one 420b, to convey out a
document sheet by the driving one 420a and the driven one 420b;
next, the reverse rotation of the shaft 436 is transmitted to the
shaft 434 through the belt 437, and the reverse rotation is further
transmitted from the driving one 420a of the pair of reversing
rollers 420 to the driven one 420b, to reverse the document and
return the document sheet to the feeding passage P1 by the driving
one 420a and the driven one 420b.
[0093] In the reversing passage P3, the conveyance-resistance
reducing rolling bars 460 for reducing the resistance to conveyance
of a document sheet are mounted; in this embodiment, the reversing
passage P3 bends in S-shape, and in these two bending portions (two
curved bent sections), the conveyance-resistance reducing rolling
bars 460 are arranged. These plural conveyance-resistance reducing
rolling bars 460 are provided rotatably on the shaft 462 between
the guide ribs 461 forming the reversing passage P3 as shown in
FIG. 9.
[0094] As shown in FIG. 8, regarding the conveyance-resistance
reducing rolling bars 460, the shaft 461 is disposed in the concave
portion 461a of the guide ribs 461 in order that the document sheet
d may hit the portion of the rolling bars deviated to the sheet
passing side from the central line O of the rolling bars, that is,
the conveyance-resistance reducing rolling bars 460 are provided in
a manner such that only a part of them is projected out of the
guide ribs 461 toward the reversing passage.
[0095] As described in the above, only a part of the
conveyance-resistance reducing rolling bars 460 is projected out of
the guide ribs 461 toward the reversing passage, and a document
sheet hits the portion of the rolling bars deviated to the sheet
passing side from the central line O of the rolling bars;
therefore, the apparatus is made compact, and the document
conveying ability is improved, which makes it possible to reduce
the frequency of the occurrence of a paper jam. Further, the
reversing passage P3 is S-shaped, and the conveyance-resistance
reducing rolling bars 460 are disposed in each of the bending
portions; therefore, the apparatus is made compact, and on top of
it, the document conveying ability in the bending portions is made
higher.
[0096] Further, in the document feeding apparatus DF of this
embodiment, as shown in FIG. 3, the hinges 470 are provided at the
deep side; the document feeding apparatus DF is of such a type as
to be opened from the image forming apparatus mainframe 1A, by
lifting upward the front side of the main body 471 of the document
feeding apparatus.
[0097] Near the front side of the document reading section 409, the
bumping member 472, which bumps against the image forming apparatus
mainframe 1A at a point, is provided, and in order to apply a force
in the direction to lift up the main body 471 of the document
feeding apparatus, the mechanism 480 for applying a rotational
force by torsion acting upward against the weight of the main body
471 itself is provided.
[0098] The up-lifting mechanism 480 is composed of the shaft 481
for applying the rotational force arranged in such a manner as to
extend from the deep side of the main body 471 of the document
feeding apparatus to the front side, and the resilient member 482
arranged at the deep side of the main body 471 of the document
feeding apparatus for giving the shaft 481 a rotational force to
lift up the main body 471. The resilient member 482 is made up of a
coil spring, and the one end 482a is fixed to the main body 471 of
the document feeding apparatus and the other end 482b is fixed to
the shaft 481 for applying the rotational force by the screw 483,
to give the shaft 481 a force for lifting up the main body 471 by
torsion.
[0099] As described in the above, the transmission of force is
carried out by the shaft 481 for applying a rotational force, and
owing to the simple mechanism for lifting up composed of the shaft
481 for applying a rotational force and the resilient member 482
for giving the shaft 481 a force to lift up the main body by
torsion, the falling down by the self-weight of the main body 471
of the document feeding apparatus is prevented.
[0100] As described in the above, when the main body 471 of the
document feeding apparatus is closed, only the bumping member 472
bumps the image forming apparatus mainframe 1A at a point near the
front side of the document reading section 409, and the falling
down by the self-weight of the main body 471 of the document
feeding apparatus is prevented by the force to lift it up;
therefore, [it is possible to make the main body 471 brought into
contact with a point near the front side of the document reading
section reliably without adjustment], the ease of operation is
good, and the document conveying ability of is made higher.
[0101] Further, in this embodiment of the invention, a document
feeding apparatus connected to a copying machine is shown, but this
invention can be applied to a document feeding apparatus to be used
by being connected to an image forming apparatus such as a printer,
or a facsimile machine, a compound machine having these plural
functions, or a light-duty printing machine.
[0102] As described in the foregoing, according to a document
feeding apparatus of this invention, it is achieved to employ a
part common to a plurality of members to reduce the number of
parts, it is possible to make the apparatus small-sized, and also
it is possible to make the document conveying ability higher.
[0103] Further, owing to the above-mentioned document feeding
apparatus, for an image forming apparatus, it is achieved to employ
a part common to a plurality of members to reduce the number of
parts, it is possible to make the apparatus small-sized, and also
it is possible to make the document conveying ability higher.
* * * * *