EP1785375B1

EP1785375B1 - Sheet article feeding apparatus and sheet article feeding method

Info

Publication number: EP1785375B1
Application number: EP06023572A
Authority: EP
Inventors: Katsuhiko Kondo; Masahiro Takeo; Kenichi Ikegami
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2005-11-15
Filing date: 2006-11-13
Publication date: 2009-04-08
Anticipated expiration: 2026-11-13
Also published as: DE602006006132D1; JP2007137533A; EP1785375A1; JP4572161B2

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet article feeding apparatus and a sheet article feeding method. More specifically, the present invention relates to a sheet article feeding apparatus and a sheet article feeding method for drawing out one by one a plurality of sheet articles stacked on a stacker and feeding them to a predetermined handling portion.

2. Description of the Related Art

A sheet article feeding apparatus for drawing out a sheet article such as an envelope from a stacker by a suction belt which sucks the sheet article utilizing sucking action of a negative pressure chamber is known.
Such sheet article feeding apparatus fall roughly into two groups depending on the state of the sheet articles to be fed on the stacker. One is a group of sheet article feeding apparatus used on the understanding that edges on at least one side of the sheet articles are aligned on the stacker. For example, Japanese Patent Application Laid-open No. Hei 07-080416 discloses a sheet article feeding apparatus used on the understanding that leading edges of sheet articles are aligned. On the other hand, Japanese Utility Model Application Laid-open No. Sho 62-186833 discloses a sheet article feeding apparatus used on the understanding that trailing edges of sheet articles are aligned. The other is a group of sheet article feeding apparatus which allow misalignment of leading edges and trailing edges of sheet articles.
In the former sheet article feeding apparatus, a suction range of the chamber can be made as large as possible within a minimum size of sheet articles to be handled. Because, in such a sheet article feeding apparatus, the chamber does not suck the subsequent sheet article, it can be avoided to draw out two sheet articles at the same time. Further, in the sheet article feeding apparatus, the suction range can be at least substantially as large as the minimum size of sheet articles. Therefore, even when a relatively thick sheet article is handled, the sheet article feeding apparatus can suck the sheet article with reliability.
However, such a sheet article feeding apparatus has to be provided with a special mechanism for aligning the edges of the sheet articles. Alternatively, an operator has to align the edges of the sheet articles manually or otherwise in advance of the feed.
On the other hand, the latter sheet article feeding apparatus can eliminate the above-described additional mechanism or trouble. However, in this sheet article feeding apparatus, a suction range of the chamber is limited in order to prevent the subsequent sheet article from being sucked at the same time. The suction range in this case is, for example, a portion where sheet articles of the minimum size always overlap within a maximum size of sheet articles to be fed. The overlap portion is considerably smaller than the minimum size of the sheet articles. Therefore, such a conventional sheet article feeding apparatus which allows misalignment of leading edges and trailing edges of sheet articles has a problem that, in particular, a thick sheet article can not be sucked with reliability.
Accordingly, a sheet article feeding apparatus is desired which, even when leading edges and trailing edges of sheet articles to be fed are misaligned, can feed with reliability the sheet articles to a subsequent handling portion without drawing out two sheet articles at the same time or without failing to suck the sheet articles.
US-A-4,357,007 discloses a sheet article feeding apparatus according to the preamble of claim 1.

SUMMARY OF THE INVENTION

An exemplary feature of the present invention is to provide a sheet article feeding apparatus and a sheet article feeding method which are capable of reliably feeding, even when leading edges and trailing edges of sheet articles to be fed are misaligned, the sheet articles to a subsequent handling portion without drawing out two sheet articles at the same time or without failing to suck the sheet articles.
A sheet article feeding apparatus according to the invention is defined in claim 1, and a sheet article feeding method according to the invention is defined in claim 10; the depending claims are related to advantageous developments of the invention.
More specifically, a sheet article feeding apparatus according to the present invention detects a position of a sheet article that is being transported, and, based on the result of the detection, controls a first suction portion and a second suction portion. Therefore, the sheet article feeding apparatus according to the present invention can, even when leading edges and trailing edges of sheet articles to be fed are misaligned, feed with reliability the sheet articles to a subsequent handling portion without drawing out two sheet articles at the same time or without failing to suck the sheet articles.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a plan view of an exemplary structure of a sheet article feeding apparatus according to an embodiment of the present invention;
FIG. 2 is an exemplary control block diagram of a control portion for controlling the sheet article feeding apparatus illustrated in FIG. 1;
FIG. 3 is a flow chart illustrating typical operation of the sheet article feeding apparatus according to the embodiment of the present invention;
FIG. 4 is a timing chart illustrating operation sequence of the sheet article feeding apparatus according to the embodiment of the present invention when the sheet article feeding apparatus feeds an ordinary sheet article;
FIG. 5 illustrates an operation of the sheet article feeding apparatus according to the embodiment of the present invention when the sheet article feeding apparatus feeds the ordinary sheet article;
FIG. 6 illustrates an operation of the sheet article feeding apparatus according to the embodiment of the present invention when the sheet article feeding apparatus feeds the ordinary sheet article;
FIG. 7 illustrates an operation of the sheet article feeding apparatus according to the embodiment of the present invention when the sheet article feeding apparatus feeds the ordinary sheet article;
FIG. 8 is a timing chart illustrating operation sequence of the sheet article feeding apparatus according to the embodiment of the present invention when the sheet article feeding apparatus feeds a thick sheet article;
FIG. 9 illustrates an operation of the sheet article feeding apparatus according to the embodiment of the present invention when the sheet article feeding apparatus feeds the thick sheet article;
FIG. 10 is a plan view of an exemplary structure of a sheet article feeding apparatus with a sensor for sensing the thickness of a sheet article provided on a separation roller; and
FIG. 11 illustrates a downstream side chamber with the inside thereof partitioned by a partition.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1 is a plan view of an exemplary structure of a sheet article feeding apparatus according to an embodiment of the present invention. The sheet article feeding apparatus includes a stacker 10 for stacking thereon sheet articles 1 in a vertically standing state, a draw-out portion 20 for drawing out one by one the sheet articles 1 stacked on the stacker 10, and a transport portion 40 for transporting the drawn-out sheet articles 1 to a downstream handling portion which is not shown.
The stacker 10 includes a conveyor belt 11, a support plate 12, and a guide plate 13. The conveyor belt 11 transports the sheet articles 1 toward the draw-out portion 20. The support plate 12 is provided so as to be movable in a state perpendicular to the conveyor belt 11, and is in contact with a back of the stacked sheet articles 1 to support the sheet articles 1 such that the sheet articles 1 do not fall down. The guide plate 13 guides leading edges of the sheet articles 1. The conveyor belt 11 and the support plate 12 are driven by a same motor (not shown) as a driving source and move at a same speed.
The draw-out portion 20 includes a sheet article pressure sensing sensor 21, an upstream side chamber 22, a downstream side chamber 23, a first solenoid valve 24, a second solenoid valve 25, a suction belt 26, pickup rollers 27, and a separation roller 28. It is to be noted that the upstream side chamber 22 and the first solenoid valve 24 form a first suction portion (upstream side suction portion) while the downstream side chamber 23 and the second solenoid valve 25 form a second suction portion (downstream side suction portion).
The sheet article pressure sensing sensor 21 is disposed at an upstream side edge of the suction belt 26. The sheet article pressure sensing sensor 21 includes a pressure sensing lever 21a and a sensing sensor 21b. The pressure sensing lever 21a is biased toward the stacker 10 (to the left in Fig. 1) by a spring 21c. The pressure sensing lever 21a is not sensed by the sensing sensor 21b when there are no sheet articles 1, but, when the sheet articles 1 are in contact with the pressure sensing lever 21, the pressure sensing lever 21a is pressed toward the right in Fig. 1, and is sensed by the sensing sensor 21b.
The upstream side chamber 22 is disposed so as to be opposed to the stacker 10 with the suction belt 26 therebetween, and is connected to a negative pressure source which is not shown. A suction surface 22a having a large number of holes (not shown) is formed on the upstream side chamber 22 on a side facing the suction belt 26. A suction range of the suction surface 22a is set to be a maximum range with which only a first sheet article 1a can be sucked and a second sheet article 1b on the stacker 10 is not sucked. For example, the suction range may be a portion where the sheet articles 1 of a minimum size always overlap within a maximum size of the sheet articles 1 to be fed.
The downstream side chamber 23 is provided on a downstream side of the upstream side chamber 22, and is connected to another negative pressure source which is not shown. A suction surface 23a having a large number of holes (not shown) is formed on the downstream side chamber 23 on a side facing the suction belt 26. A suction range of the suction surface 23a is set to be a range from a leading edge position of the sheet articles 1 stacked on the stacker 10 to the pickup rollers 27.
The first solenoid valve 24 is provided between the upstream side chamber 22 and the negative pressure source related to the first solenoid valve 24 and makes the internal pressure of the upstream side chamber 22 negative pressure or atmospheric pressure. Negative pressure refers to pressure below atmospheric pressure.
The second solenoid valve 25 is provided between the downstream side chamber 23 and the negative pressure source related to the second solenoid valve 25 and makes the internal pressure of the downstream side chamber 23 negative pressure or atmospheric pressure.
The suction belt 26 is an endless belt having suction holes 26a for sucking the sheet articles 1 formed all around the perimeter thereof. The suction belt 26 is driven by a servo motor 29 and rotates along the suction surfaces 22a and 23a.
The pickup rollers 27 are provided in a transport area for the sheet articles 1 of the suction belt 26, and transports the picked-up sheet articles 1 toward the downstream transport portion 40. It is to be noted that the distance from an upstream edge 23d of the downstream side chamber 23 to the pickup rollers 27 is set to be shorter than a minimum length of the sheet articles 1 to be fed. The pickup rollers 27 include a driving roller 27a driven by a motor 30, a driven roller 27b in contact with the driving roller 27a, a support arm 27c for movably supporting the driven roller 27b, and a spring 27d for biasing the support arm 27c in a predetermined direction.
The separation roller 28 is provided between the stacker 10 and the pickup rollers 27 at a position downstream from an upstream edge 22b of the upstream side chamber 22 by the minimum length of the sheet articles 1. The separation roller 28 separates the first sheet article 1a and the second sheet article 1b and prevents two sheet articles 1 from being fed at the same time. Predetermined load is imposed on the separation roller 28 in a direction of the suction belt 26. The separation roller 28 rotates in a direction opposite to the direction of feed of the sheet articles 1.
Photoelectric sensors 31 to 34 for sensing a position of the sheet articles 1 being transported are disposed in the transport area for the sheet articles 1 of the suction belt 26. The photoelectric sensor 31 detects whether a leading edge of the first sheet article 1a is picked up by the pickup rollers 27 or not. The photoelectric sensor 32 is provided at a position upstream from the separation roller 28 by a predetermined distance. The photoelectric sensor 32 detects whether the leading edge or a trailing edge of the first sheet article 1a reaches a predetermined position of the suction surface 23a of the downstream side chamber 23. The photoelectric sensor 33 detects the trailing edge of the first sheet article 1a. The photoelectric sensor 34 detects whether the leading edge of the first sheet article 1a reaches the separation roller 28 or not.
FIG. 2 is an exemplary control block diagram of a control portion 50 for controlling the sheet article feeding apparatus illustrated in FIG. 1. The control portion 50 is equipped with, for example, a sequencer and a microcomputer which exercise control based on a program, and controls the whole sheet article feeding apparatus. The sheet article pressure sensing sensor 21, the photoelectric sensors 31 to 34, a mode selector switch 35, and the like are connected to an input side of the control portion 50. A motor for driving the conveyor belt 11 and the support plate 12, the first solenoidvalve 24, the second solenoid valve 25, the servo motor 29, the motor 30, and the like are connected to an output side of the control portion 50.
Results of, for example, the sheet article pressure sensing sensor 21, the photoelectric sensors 31 to 34, and the mode selector switch 35 are inputted to the control portion 50. Based on the inputted results, the control portion 50 controls the first solenoid valve 24 and the second solenoid valve 25 to make the internal pressure of the upstream side chamber 22 and the internal pressure of the downstream side chamber 23 negative pressure or atmospheric pressure.
The mode selector switch 35 is for selecting a mode for handling ordinary sheet articles 1 or a mode for handling thick sheet articles 1. The mode selector switch 35 may be formed of, for example, an operation button or the like.
FIG. 3 is a flow chart illustrating typical operation of the sheet article feeding apparatus described above. First, the control portion 50 confirms a handling mode which is now selected by the mode selector switch 35 (Step S1) . Then, the control portion 50 determines whether the selected handling mode is the mode for handling the ordinary sheet articles 1 or the mode for handling the thick sheet articles 1 (Step S2). The control portion 50 executes feed suitable for each handling mode (Step S3 and Step S4).
It is to be noted that, in the above, ordinary sheet articles refer to sheet articles which are thinner than a predetermined thickness, and thick sheet articles refer to sheet articles which are thicker than the predetermined thickness.
In the following, operation of feeding the ordinary sheet articles 1 and operation of feeding the thick sheet articles 1 of the sheet article feeding apparatus are described in this order.
First, operation of feeding the ordinary sheet articles 1 (detailed operation of Step S3 in FIG. 3) is described in the following mainly with reference to a timing chart of FIG. 4. The sheet articles 1 stacked on the stacker 10 are made to start moving by the conveyor belt 11 and the support plate 12 toward the draw-out portion 20 (at T1 in FIG. 4). Then, the rightmost sheet article 1a presses the pressure sensing lever 21a. When the sensing sensor 21b senses displacement of the pressure sensing lever 21a, the control portion 50 stops driving the conveyor belt 11 and the support plate 12 (at T2 in FIG. 4).
In this case, as illustrated in FIG. 5, the control portion 50 makes only the internal pressure of the upstream side chamber 22 negative pressure and makes the internal pressure of the downstream side chamber 23 atmospheric pressure. More specifically, almost as soon as the sensing sensor 21b senses the pressure sensing lever 21a, the first sheet article 1a is sucked only by the suction surface 22a of the upstream side chamber 22.
After the sensing sensor 21b senses the pressure sensing lever 21a and after a short time period Tw for suction, the servo motor 29 is driven and the suction belt 26 starts rotation to start transport of the first sheet article 1a (at T3 in FIG. 4).
Then, when the photoelectric sensor 32 senses the leading edge of the first sheet article 1a, the control portion 50 makes the internal pressure of the downstream side chamber 23 negative pressure, and the leading edge of the first sheet article 1a is sucked (at T4 in FIG. 4) . More specifically, in this case, as illustrated in FIG. 6, the first sheet article 1a is sucked by both the upstream side chamber 22 and the downstream side chamber.23.
Then, when the photoelectric sensor 34 senses the leading edge of the first sheet article 1a, in other words, when the first sheet article 1a reaches the separation roller 28, as illustrated in FIG. 7, the control portion 50 switches the internal pressure of the upstream side chamber 22 to atmospheric pressure (at T5 in FIG. 4). In this case, as described above, the separation roller 28 is provided at a position downstream from the upstream edge 22b of the upstream side chamber 22 by the minimum length of the sheet articles 1. Therefore, even when the first sheet article 1a is of a minimum size, the upstream side chamber 22 does not suck the second sheet article 1b.
Then, when the photoelectric sensor 31 senses the leading edge of the first sheet article 1a, in other words, when the first sheet article 1a is picked up by the pickup rollers 27, the control portion 50 switches the internal pressure of the upstream side chamber 22 and the internal pressure of the downstream side chamber 23 to atmospheric pressure. Further, the control portion 50 stops the servo motor 29 as the driving source of the suction belt 26 (at T6 in FIG. 4). The first sheet article 1a is captured by the pickup rollers 27 which always rotate at the same speed as that of the suction belt 26, and is transported to the downstream transport portion 40.
Then, when the photoelectric sensor 32 detects the trailing edge of the first sheet article 1a, the control portion 50 makes the internal pressure of the upstream side chamber 22 negative pressure and the second sheet article 1b is sucked (at T7 in FIG. 4). After a short time period Tw for suction, the, control portion 50 rotates the servo motor 29 and feed of the second sheet article 1b by the suction belt 26 is started (at T8 in FIG. 4).
It is to be noted that, when the second sheet article 1b is separated by the separation roller 28 after the second sheet article 1b is pulled together with the first sheet article 1a by friction, the photoelectric sensor 32 does not detect the trailing edge of the first sheet article 1a during the feed of the first sheet article 1a. In this case, the control portion 50 may switch the internal pressure of the upstream side chamber 22 to negative pressure based on detection of the trailing edge of the first sheet article 1a by the photoelectric sensor 33 to thereby suck the second sheet article 1b.
Next, operation of feeding the thick sheet articles 1 (detailed operation of Step S4 in FIG. 3) is described in the following mainly with reference to a timing chart of FIG. 8. Operation of feeding the thick sheet articles 1 while being transported is the same as that of feeding the ordinary sheet articles 1 illustrated in the timing chart of FIG. 4. However, operation of starting transport is different. More specifically, when the thick sheet articles 1 are fed, the control portion 50 makes not only the internal pressure of the upstream side chamber 22 but also the internal pressure of the downstream side chamber 23 negative pressure as illustrated in FIG. 9 at the start of transport of the first sheet article 1a by the suction belt 26 (at T3' in FIG. 8). More specifically, the thick sheet article 1 is sucked by the two chambers at the start of transport, and thus, it is not removed easily from the suction belt 26.
In addition, in this case, the thick sheet articles 1 are heavy, and, because of their thickness, the distance between the second sheet article 1b and the suction surface 23a of the downstream side chamber 23 is larger than that in the case of the ordinary sheet articles 1. Therefore, when, for example, the second sheet article 1b is larger in size than the first sheet article 1a, it is extremely unlikely that the second sheet article 1b is sucked together with the first sheet article 1a.
In the sheet article feeding apparatus according to this embodiment described above, only the internal pressure of the upstream side chamber 22 is made to be negative pressure at the start of operation of the suction belt 26 when the ordinary sheet articles 1 are fed. Further, the suction range of the suction surface 22a is set to be a range with which only the first sheet article 1a is sucked and the second sheet article 1b on the stacker 10 is not sucked. Therefore, even when the sheet articles 1 are stacked on the stacker 10 with the leading edges and the trailing edges of the sheet articles 1 misaligned, the sheet article feeding apparatus does not suck the first sheet article 1a and the second sheet article 1b at the same time.
In addition, in the sheet article feeding apparatus, not only the internal pressure of the upstream side chamber 22 but also the internal pressure of the downstream side chamber 23 is made to be negative pressure when the photoelectric sensor 32 senses the leading edge of the first sheet article 1a. Because the first sheet article 1a is strongly sucked by the two chambers while being transported, the first sheet article 1a is not removed easily from the suction belt 26.
On the other hand, in the sheet article feeding apparatus, not only the internal pressure of the upstream side chamber 22 but also the internal pressure of the downstream side chamber 23 is made to be negative pressure at the start of operation of the suction belt 26 when the thick sheet articles 1 are fed. Because the thick sheet article 1 is sucked by the two chambers, the thick sheet article 1 is not removed easily from the suction belt 26.
In other words, the sheet article feeding apparatus according to this embodiment described above can, even when leading edges and trailing edges of sheet articles to be fed are misaligned, feed with reliability the sheet articles to a subsequent handling portion without drawing out two sheet articles at the same time or without failing to suck the sheet articles.
Further, because the sheet article feeding apparatus is provided with the mode selector switch 35 for selecting the mode for handling ordinary sheet articles or the mode for handling thick sheet articles, feed suitable for the thickness of the sheet articles 1 to be fed can be selected.
Further, the sheet article feeding apparatus makes the internal pressure of the downstream side chamber 23 atmospheric pressure when the first sheet article 1a is picked up by the pickup rollers 27. Therefore, the sheet article feeding apparatus can prevent breakage of the sheet articles 1 and decrease in the speed of transport due to suction by the downstream side chamber 23 during pickup.
Further, in the sheet article feeding apparatus, the pickup rollers 27 are provided in the transport area for the sheet articles 1 of the suction belt 26. Because the sheet article feeding apparatus can make short the distance from the upstream side chamber 22 and the downstream side chamber 23 to the pickup rollers 27, shorter sheet articles 1 can be fed.
Further, in the sheet article feeding apparatus, the distance from the upstream edge 23d of the downstream side chamber 23 to the pickup rollers 27 is set to be shorter than the minimum length of the sheet articles 1 to be fed. Therefore, the first sheet article 1a and the second sheet article 1b are not sucked by the downstream side chamber 23 at the same time.
It is to be noted that the mode selector switch 35 is not limited to the operation button described above. For example, as illustrated in FIG. 10, the mode selector switch 35 may be a sensor 36 provided on the separation roller 28 or the like for detecting the thickness of the sheet articles 1. In this case, the control portion 50 can automatically select a handling mode based on the result of detection by the sensor 36. The above structure saves an operator trouble, decreases human error such as a mistake in selecting a mode, and shortens time necessary for feeding the sheet articles 1.
Further, as described with reference to FIG. 4, when the photoelectric sensor 32 senses the leading edge of the first sheet article 1a, the leading edge is sucked by the downstream side chamber 23. However, in this case, the sheet articles 1a has not reached a downstream portion of the downstream side chamber 23, and thus, atmospheric pressure which flows in from the downstream portion decreases the negative pressure in the downstream side chamber 23. Therefore, as illustrated in FIG. 11, the inside of the downstream side chamber 23 is partitioned by a partition 23c having a small vent hole 23b formed therein. The partition 23c suppresses decrease in the negative pressure in the downstream side chamber 23.
It is to be noted that, although, in the above description, each of the first suction portion and the second suction portion includes a chamber and a solenoid valve, the structures of the first suction portion and the second suction portion are not necessarily limited thereto.
The sheet article feeding apparatus described above may be applied to any apparatus for feeding a sheet article to a subsequent handling portion. For example, the sheet article feeding apparatus may be applied to an apparatus for counting or sorting paper money or gift certificates. In particular, the sheet article feeding apparatus is suitable as a mail processor which is required to feed one by one with reliability sheet articles of various sizes with their leading edges not so aligned.

Claims

A sheet article feeding apparatus, comprising:
a suction belt (26) which takes a first sheet article (1a) from a stack and transports the sheet article;

a first suction portion (22) which sucks the sheet article onto the suction belt (26);

at least one second suction portion (23) provided on a downstream side of the first suction portion (22) in a transporting direction;

at least one position detecting portion (31-34) which detects a position of the sheet article (1) that is being transported; and

a control portion (50) which controls the first suction portion (22) and the second suction portion (23) based on a result of detection of the position detecting portion, characterized in that when a leading edge of the sheet article reaches the position of a separation roller (28) which separates one sheet article from stacked sheet articles, the control portion (50) controls the first suction portion to stop suction of the sheet article onto the suction belt.
A sheet article feeding apparatus according to claim 1, wherein the position detecting portion (32) is provided at a predetermined position in a suction area of the second suction portion.
A sheet article feeding apparatus according to claim 1, wherein the position detecting portion (31) is provided at a position corresponding to a position where a leading edge of the sheet article is picked up.
A sheet article feeding apparatus according to claim 1, wherein the position detecting portion (34) is provided at a position corresponding to a separation roller (28) which separates one sheet article from stacked sheet articles.
A sheet article feeding apparatus according to claim 1, wherein, when a leading edge of the sheet article reaches a predetermined position in a suction area of the second suction portion (23), the control portion (50) controls the second suction portion (23) to suck the sheet article (1) onto the suction belt.
A sheet article feeding apparatus according to claim 1, wherein, when a leading edge of the sheet article is picked up, the control portion (50) controls the second suction portion (23) to stop suction of the sheet article onto the suction belt.
A sheet article feeding apparatus according to claim 1, wherein, when a trailing edge of the sheet article reaches a predetermined position in a suction area of the second suction portion (23), the control portion controls the first suction portion (22) to suck a sheet article subsequent to the sheet article onto the suction belt.
A sheet article feeding apparatus according to claim 1, wherein, when the suction belt (26) starts transport of the sheet article, the control portion controls the first suction portion (22) to suck the sheet article onto the suction belt if the sheet article is thinner than a predetermined thickness, and the control portion controls the first suction portion (22) and the second suction portion (23) to suck the sheet article onto the suction belt if the sheet article is thicker than the predetermined thickness.
A sheet article feeding apparatus according to claim 1, further comprising a roller (27) for picking up a sheet article whose whole length is on the suction belt.
A sheet article feeding method for transporting a sheet article by sucking a first sheet article from a stack onto a suction belt by a suction portion, comprising the steps of:
detecting a position of a sheet article that is being transported; and

controlling a suction portion (22) on an upstream side and a suction portion (23) on a downstream side in a transporting direction based on a result of detection of the position, characterized by controlling the suction portion on the upstream side (22) to stop suction of the sheet article onto the suction belt, when a leading edge of the sheet article reaches the position of a separation roller (28) which separates one sheet article from stacked sheet articles.
A sheet article feeding method according to claim 10, wherein the step of controlling the suction portion comprises the step of controlling the suction portion on the downstream side (23) to suck the sheet article onto the suction belt, when the sheet article reaches a predetermined position in a suction area of the suction portion on the downstream side.
A sheet article feeding method according to claim 10, wherein the step of controlling the suction portion comprises the step of controlling the suction portion on the downstream side (23) to stop suction of the sheet article onto the suction belt, when a leading edge of the sheet article is picked up.
A sheet article feeding method according to claim 10, wherein the step of controlling the suction portion comprises the step of controlling the suction portion of the upstream side (22) to suck a sheet article subsequent to the sheet article onto the suction belt, when a trailing edge of the sheet article reaches a predetermined position in the suction area of the suction portion on the downstream side (23).
A sheet article feeding method according to claim 10, wherein the step of controlling the suction portion comprises the step of, when the suction belt starts transport of the sheet article, controlling the suction portion on the upstream side (22) to suck the sheet article onto the suction belt if the sheet article is thinner than a predetermined thickness, and controlling the suction portion on the upstream side (22) and the suction portion on the downstream side (23) to suck the sheet article onto the suction belt if the sheet article is thicker than the predetermined thickness.