JP3204144B2 - Document feeder and image reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder for feeding a document and an image reading apparatus provided with the document feeder.

[0002]

2. Description of the Related Art In recent years, image reading apparatuses have been widely used for reading an image from a document. And, in order to automatically feed a document to the image reading apparatus,
A document feeder is often provided.

An image reading apparatus mainly used for business uses a document feeder capable of placing a large number of documents (for example, about several hundred to 1,000 sheets) on a hopper table at a time, thereby efficiently reading the documents. There is something that tries to realize.

Here, such a document feeder is generally required to satisfy the following conditions.

First, the angle (same as the angle of the hopper table) of the original toward the paper feed roller of the image reading apparatus must be within an allowable range from the ideal angle regardless of the amount of the original on the hopper table. Must. This is because, if the tolerance is out of the allowable range, a paper feeding error occurs, such as jamming of the document or feeding of the document at a time.

Second, it is desirable that the external dimensions be as small as possible in order to save installation space.

Third, it is desirable that the power for raising and lowering the original (hopper table) be as small as possible. This is because it is desired to save power consumption and reduce the size of the driving source.

On the other hand, conventional document feeders can be roughly classified into two types: a parallel lift type and a swing type.

In the parallel lift type, the originals are horizontally stacked in a box-shaped or frame-shaped magazine, and the magazines are moved up and down horizontally using an elevating means. To the next level.

However, according to such a configuration,
There are the following problems. That is, a distributed load due to the document acts on the magazine. When a large number of originals are placed, the distributed load becomes considerably large.

In the case of the parallel lift type, both reactive forces for supporting both ends of the document at both ends must be borne by the power of the driving source with respect to the distributed load.
Further, not only the manuscript but also the magazine itself must be raised and lowered. Therefore, the drive source must be able to generate a considerable power.

For this reason, there is a problem that the size of the document feeder becomes large, a large-capacity drive source is required, and power consumption is increased.

In the swing type, the end of the hopper table is pivotally supported on a fixed shaft support, and the hopper table is swung about the shaft support according to the amount of documents on the hopper table.

According to this configuration, even when a large amount of documents are placed on the hopper table, the reaction force on the shaft support portion of the reaction force against the distributed load due to the document is the static reaction force of the shaft support portion. It is burdensome, and the burden on the drive source is unnecessary. For this reason,
The power required for the drive source is smaller than that of the parallel lift type, which is preferable.

However, in such a configuration,
To keep the angle of the hopper table within the allowable range, the length of the hopper table (radius about the shaft support)
Must be lengthened, and the size of the document feeder increases.

Conversely, if the length of the hopper table is reduced, the angle at which the hopper table swings must be increased in order to cope with a large number of documents. However, the reading efficiency is greatly reduced.

[0017]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a document feeder which is compact and can suppress paper feed errors, and an image reading apparatus using the same.

[0018]

According to a first aspect of the present invention, there is provided a sheet feeding apparatus comprising: a table on which a document is placed; and elevating means for elevating the table. The elevating means swings the table when the table is located between the first position and a second position above the first position, and moves the table from the second position to the second position. The hopper table is horizontally moved when it is located between the third positions set above the position.

[0019]

According to a first aspect of the present invention, there is provided a sheet feeding apparatus comprising: a table on which an original is placed; and elevating means for elevating the table. When the table is rocked between the second positions above the first position, the table is swung so that the table is set above the second position from the second position. When between the positions, the hopper table is moved horizontally.

Therefore, when the amount of originals on the hopper table is large and the distance from the hopper table to the uppermost original is long, the hopper table is between the lower limit position and the switching position. At this time, since the amount of the original is large, the distributed load due to the original acting on the hopper table is large.

However, when the hopper table is between the lower limit position and the switching position, the hopper table is oscillated, so that the hopper table is oscillated similarly to the oscillating type document feeder. Only a small amount of power is required, and the drive source can be made compact.

When the amount of originals on the hopper table decreases, the hopper table is located between the switching position and the upper limit position. At this time, since the amount of the original is small, the distributed load due to the original is also small.
Not much power is needed for the drive source.

Further, the angle of the hopper table is maximum at the lower limit position, decreases from the lower limit position to the switching position, and is horizontal (angle 0) from the switching position to the upper limit position.

That is, if the angle of the hopper table is within the allowable range when the hopper table is at the lower limit position, the hopper table always has an angle within the allowable range at any position, and the paper feed error Can be suppressed.

In addition, in this way, not only can a large number of documents be accommodated, but also the length of the hopper table can be made substantially the same as the length of the documents, and the device can be made compact.

According to a third aspect of the present invention, there is provided an image reading apparatus including the above-mentioned document feeder, a group of conveying rollers for conveying the fed original, and a reading unit for reading the conveyed original.

Therefore, since the size of the document feeder is compact and feeding mistakes can be suppressed, the entire image reading device can be made compact and the document can be read efficiently.

Next, an embodiment of the present invention will be described with reference to the drawings. First, an overall image reading apparatus including a document feeder according to an embodiment of the present invention will be outlined with reference to FIG. As shown in FIG. 1, a document feeder A is provided in the image reading apparatus.

The document feeder A has a hopper table 1 on which about 1 to 1000 documents 2 are placed. The hopper table 1 is raised and lowered by lifting means including a hopper motor 3 as a drive source and a drive mechanism described later.

Here, the hopper table 1 is at the lower limit position S1 indicated by a solid line when the original 2 is placed at the maximum, and the front edge 1a of the hopper table 1 is directed downward and the rear edge 1b is directed upward. To take an inclined position.

The hopper table 1 is located at the lower limit position S1.
From above, and becomes horizontal at the switching position S2. Then, it rises horizontally from the switching position S2 to the upper limit position S3.

The hopper table 1 is moved up and down so that the uppermost document 2 is always at a certain level (a level in contact with the feeding roller 4).
From the switching position S2, from the switching position S2 to the upper limit position S3,
As the document is raised, the documents 2 on the hopper table 1 are fed one after another, and the amount of the document 2 on the hopper table 1 is reduced.

The lower limit position sensor 5 detects whether the hopper table 1 is at the lower limit position S1, and the switching position sensor 6 detects whether the hopper table 1 is at the switching position S2.

The hopper height sensor 7 illuminates a portion of the hopper table 1 where the document 2 is not placed, and receives the reflected light to detect the height of the hopper table 1.

The feeding roller 4 serving as feeding means has an arrow N
The document is rotated in one direction, and the uppermost document 2 is fed out in the direction of arrow M. In the vicinity of the feeding roller 4, a detector 8, which is pivotally supported at a middle corner thereof by a shaft support 9, is swingably supported. The lower end 8a of the detector 8 comes into contact with the uppermost document 2 and the document presence sensor 10 outputs whether the upper end 8b of the detector 8 has been detected.

Here, if there is at least one document 2 on the hopper table 1, the document 2 comes into contact with the lower end portion 8a, and the detector 8 swings around the shaft support 9. For this reason, the upper end 8 b is not detected by the document presence sensor 10.

Conversely, if there is no document 2 on the hopper table 1, the detector 8 does not swing, and the document presence sensor 10 detects the upper end 8b. That is, the document presence sensor 10
By monitoring the upper end 8b, it is detected whether there is at least one document 2 on the hopper table 1.

Next, the image reading apparatus will be described. Immediately beside the feeding roller 4, there are provided a separation roller 12 that rotates in the forward direction M of the document 2 and a retard roller 11 that rotates in the reverse direction.
15 and 16 are provided.

The separation roller 12 and the retard roller 11
When driven by the paper feed motor 13 and rotated, the transport rollers 14
15 and 16 are rotated by a transport motor 17.

The front side of the document 2 conveyed in the conveying direction M is read by the first reading unit 18, and the back side is read by the second reading unit 1.
Read at 9. The image signals output from these reading units are digitized by the reading control unit 20. Also,
The paper feed motor 13 and the transport motor 17 are
Driven by And each of the above elements is C
Digital image information output from the reading control unit 20 is controlled by the main control unit 22 having a PU and a RAM, and is processed by the main control unit 22.

Next, the driving mechanism will be described with reference to FIGS. As shown in FIG. 2, the document feeder according to the present embodiment includes:
It has a stationary chassis 30 and a sub-chassis 31 integrally formed with the chassis 30.

A hopper motor 3 composed of a pulse motor is fixed to the sub-chassis 31, and an output shaft 32 of the hopper motor 3 has a gear train 33 supported by the sub-chassis 31.
Are connected. The torque of the output shaft 32 is transmitted to a vertically rotating pinion 35 via a gear train 33. Of course, the pinion 35 is mounted on the shaft 34 so as to be rotatable with respect to the sub-chassis 31.

As shown in FIG. 3, one end of the end of the first link 37 on the rear edge 1b side of the hopper table 1 is provided on the chassis 30, and
It is pivotally supported by the shaft support 36. The other end of the first link 37 on the front edge 1 a side is pivotally supported by the first shaft 38 on the front edge 1 a side of the hopper table 1.

The drive mechanism has a second link 40 intersecting with the first link 37. One end of the second link 40 on the front edge 1a side of the hopper table 1 is provided on the chassis 30 and is pivotally supported by an immovable second shaft support 39.

The other end of the hopper table 1 on the rear edge 1b side is pivotally supported by the second shaft 41 on the rear edge 1b side of the hopper table 1.

A vertically long projection 45 is provided in the middle of the first link 37, and the first shaft support 36
An arc-shaped long hole 46 having a center at the center is formed. The bottom of the long hole 46 is a pin seat 47.

A connecting pin 44 protrudes from the middle of the second link 40 and is slidably engaged with the elongated hole 46.

Further, on the side surface of the first link 37, the first link
An arc-shaped rack 42 centered on the shaft support 36 is fixed by set screws 43, and the rack 42 is fixed to the pinion 35.
Is engaged.

Next, the operation of the driving mechanism will be described with reference to FIG. First, when a large number of documents 2 are placed on the hopper table 1, the hopper table 1 is at the lower limit position S1, as shown by the solid line in FIG. At this time, rack 4
The upper end of the pin 2 meshes with the pinion 35, and the connecting pin 44 is engaged with the top of the elongated hole 46. Also, hopper table 1
Is in the allowable range α.

Next, when the original 2 is fed out and decreases, the pinion 35 rotates and the rack 42 slowly rotates. Thereby, the hopper table 1 is moved to the lower limit position S
1 and a swing area T1 between the switching position S2. At this time, the connecting pin 44 remains stopped, and the elongated hole 46 slides upward with respect to the connecting pin 44. Accordingly, during this time, the second link 40 does not move at the position indicated by the solid line, and the power transmitted to the pinion 35 is
7, the hopper table 1 is simply the first shaft support 3
Only the swing about 6 is performed.

Next, as shown by the broken line, when the hopper table 1 reaches the switching position S2, the attitude of the hopper table 1 becomes horizontal. Further, as a result of sliding of the long hole 46 with respect to the connecting pin 44, the connecting pin 44 comes into contact with the pin seat 47 at the bottom of the long hole 46.

By this contact, the second link is connected to the first link 37.
The link 40 is connected, and the first link 37 and the second link 4
0 constitutes a parallel link mechanism. Therefore, after this, the power transmitted from the pinion 35 is transmitted not only to the first link 37 but also to the second link 40.

As a result, when the number of the originals 2 is further reduced and the hopper table 1 rises in the horizontal movement area T2 from the switching position S2 to the upper limit position S3, the hopper table 1 keeps the horizontal posture. . Thereby, the hopper table 1 can be raised horizontally in the horizontal movement area T2.

As described above, in the document feeder of this embodiment,
Both the swinging and the horizontal movement of the hopper table 1 are realized by only a single link mechanism, and a compact mechanism, with a small power and without increasing the angle or length of the hopper table 1. In addition, appropriate feeding can be performed.

The document feeder of this embodiment has the above-described configuration. Next, the operation of the document feeder will be described with reference to FIG.

Here, the document feeder of the present embodiment is adapted to cope with a large number of documents (about 1000) as described above. Is not always set to the original, and the hopper table 1 may have only a certain amount of the original 2 at the start of the operation. Regardless of the amount of the original 2, if the hopper table 1 is always moved from the lower limit position S1 as shown by the solid line in FIG. 3, a wasteful time is required until the uppermost original 2 reaches a predetermined level. Is consumed.

Therefore, in this embodiment, not only the lower limit position S1 but also the switching position S2 can be selected as the rising start height Hx of the hopper table 1. As a result, it is possible to save wasted time of ascent and to further enhance the working efficiency.

In step 1 of FIG. 4, the above-described starting height Hx is set, and the hopper table 1 is set at this height.

Next, the main controller 22 controls the hopper table 1
Is raised (step 2), and the output of the document presence sensor 10 is inspected (step 3). If manuscript 2 is "Yes",
After confirming that there is no abnormality in the height of the hopper table 1 indicated by the hopper height sensor 7 (step 4), the hopper table 1 is raised until the document 2 reaches the level of the feeding roller 4 (step 2).

Here, the main controller 22 does not need to monitor whether the hopper table 1 is in the swinging area T1 or the horizontal moving area T2. This is because the drive mechanism appropriately moves the hopper table 1 without the control of the main control unit 22.

When the original 2 reaches the level of the feed roller 4, the ascent of the hopper table 1 is stopped (step 5). The main control unit 22 uses the reading control unit 20 and the motor control unit 21 to transfer the document 2 fed from the feeding roller 4 one by one in the transport direction M by a pair of the separation roller 12 and the retard roller 11. Then, the first reading unit 18 and the second reading unit 19 read the front and back surfaces of the document 2 (step 6).

The above operation is repeated (steps 7 to 10). When the document 2 is no longer detected, the feeding and reading are completed (step 11), and the hopper table 1 is returned to the starting height Hx (step 12). ).

[0063]

The present invention has been configured as described above.
Even for a large number of documents, the power source of the driving source and the size of the hopper table are small, and the hopper table can be configured compactly.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a driving mechanism according to the embodiment of the present invention.

FIG. 3 is a side view of the driving mechanism according to the embodiment of the present invention.

FIG. 4 is a control flowchart of the document feeder according to the embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hopper table 2 original 3 hopper motor 4 feeding roller 36 first shaft support 37 first link 38 first shaft 39 second shaft support 40 second link 41 second shaft 44 connecting pin 46 long hole 47 pin seat

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-178473 (JP, A) JP-A-5-270667 (JP, A) JP-A-6-156749 (JP, A) JP-A-10-107 283457 (JP, A) Japanese Utility Model Application Hei 2-137331 (JP, U) Japanese Utility Model Application Hei 2-72236 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06T 1/00 420 B65H 1/14 322 H04N 1/00 108

Claims (4)

(57) [Claims] A table on which a document is placed; and elevating means for elevating the table, wherein the elevating means comprises:
When the table is located between the first position and a second position above the first position, the table is swung, and the table is moved from the second position to a position higher than the second position. A sheet feeding device, wherein the hopper table is horizontally moved when the hopper table is located between a third position set upward. 2. The sheet feeding device according to claim 1, further comprising a setting unit that sets a position at which the table is started to be raised by the lifting unit. 3. An image reading device, comprising: the sheet feeding device according to claim 1; a conveying roller group for conveying a fed document; and a reading unit for reading the conveyed document. 4. The apparatus according to claim 1, wherein the reading unit reads a first surface of the document.
3. The image reading apparatus according to claim 1, further comprising: a reading unit; and a second reading unit that reads a back surface of the document.