Information
-
Patent Grant
-
6776409
-
Patent Number
6,776,409
-
Date Filed
Monday, August 19, 200222 years ago
-
Date Issued
Tuesday, August 17, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 271 189
- 271 246
- 271 253
- 271 273
- 271 207
- 271 176
- 271 198
- 271 199
- 271 31
- 271 220
- 414 789
- 414 7907
-
International Classifications
-
Abstract
A batch sheet feeder has an upstream first conveyor section arranged to convey sheets singly in a downstream direction to a downstream second conveyor section. The second conveyor section has an upper second conveying section and a lower second conveying section forming a gap therebetween. The gap is largest at an upstream end of the second conveyor section and diminishes in size toward a downstream end of the second conveyor section. A gate positioned proximate the downstream end of the second conveyor section selectively blocks sheets fed along the second conveyor section. In another embodiment, the sheet feeder has a sheet conveyor, sheet sensor, and visual attribute sensor. The visual attribute sensor has a field of view covering an area of the conveyor at a certain downstream location so as to sense an area of any sheet on the conveyor at this downstream location. The visual attribute sensor can compare a sensed area of a sheet at the downstream location with a stored visual attribute. In this way, where the sheets of a batch are different, the visual attribute sensor can be used to verify that a sheet of a batch has visual characteristics matching those of the expected sheet at that ordinal position in the batch. This assists in ensuring a batch is not faulty. In a related method of verifying batches of sheets, for each sheet at a given ordinal position in each batch a visual attribute measure for at least an area of the sheet is obtained. A comparison is made of the visual attribute measure with a stored visual attribute measure. Each batch is selectively verified based on this comparison.
Description
FIELD OF THE INVENTION
This invention relates to a sheet feeder particularly useful in feeding batches of sheets and to a method of verifying batches of sheets.
BACKGROUND OF THE INVENTION
In known batch sheet feeders, sheets may be fed singly from a stack through parallel belts and counted while they are transported through the parallel belts. The sheets are then either fed individually to a target (e.g., a box between flights of a downstream conveyor) so as to be stacked in batches directly on the target, or fed and stacked onto some sort of drop table (e.g., a reciprocating table) to be dropped vertically onto or into their target as a batch.
One drawback with singly feeding sheets to the target is that the target area must not move or be obstructed during the entire time that a given batch is being fed. By stacking the batch on a drop table, this problem is avoided in that the entire batch is dropped to the target together as one group. However, the speed at which the batch drops is fixed (by gravity) and the feeding of sheets to the table must halt for the time it takes the drop table to open, the product to drop and the table to return to its ready position. Another drawback is that the target must be able to accept the product from the top. With both approaches, a further difficulty in stacking the sheets is in controlling the trailing edge of a sheet so that the next sheet does not crash into it. This difficulty increases with the speed of feeding.
While known batch sheet feeders count sheets to ensure there is a proper number of sheets in each batch, in many applications the sheets of a batch are printed differently. Thus, each sheet of a batch may be unique in the batch. In such applications, another problem is ensuring that each batch has a proper set of sheets. Another drawback with the noted types of batch sheet feeder is that they have no mechanism to address this problem.
This invention seeks to provide a batch sheet feeder that avoids at least one of these drawbacks.
SUMMARY OF INVENTION
According to the present invention, there is provided a batch sheet feeder comprising: an upstream first conveyor section arranged to convey sheets singly in a downstream direction to a downstream second conveyor section; said second conveyor section comprised of an upper second conveying section and a lower second conveying section forming a gap therebetween, said gap being largest at an upstream end of said second conveyor section and diminishing in size toward a downstream end of said second conveyor section; and a gate positioned proximate said downstream end of said second conveyor section for selectively blocking sheets from exiting said second conveyor section.
According to another aspect of the invention, there is provided a batch sheet feeder, comprising: a lower endless conveyor; an upper endless conveyor arranged with respect to said lower conveyor so as to form a sheet feed path between said lower conveyor and said upper conveyor for feeding sheets in a downstream direction; said lower conveyor substantially paralleling said upper conveyor along an upstream first section, said lower conveyor jogging away from said upper conveyor at an upstream end of a downstream second section so as to form a gap between said lower conveyor and said upper conveyor at said second section that is larger than any gap between said lower conveyor and said upper conveyor at said first section.
According to a further aspect of the invention, there is provided a sheet feeder, comprising: a sheet conveyor; a sheet sensor; a visual attribute sensor having a field of view covering an area of said conveyor at a certain downstream location so as to sense an area of any sheet on said conveyor at said downstream location, said visual attribute sensor for comparing a sensed area of a sheet at said downstream location with a stored visual attribute.
According to another aspect of the present invention, there is provided a method of verifying batches of sheets, comprising: for each sheet at a given sheet position in each batch of sheets: obtaining a visual attribute for at least an area of said each sheet; comparing said visual attribute with a stored visual attribute; and selectively verifying said each batch based on said comparing.
According to a further aspect of the invention, there is provided a method of verifying batches of sheets, comprising: conveying sheets in a sheet conveyor; sensing sheets with a sheet sensor; sensing a visual attribute with a visual attribute sensor having a field of view covering an area of said conveyor at a certain downstream location so as to sense an area of any sheet on said conveyor at said downstream location; verifying batches of sheets at a processor receiving an output from said visual attribute sensor and said sheet sensor.
Other features and advantages of the invention will be apparent after reviewing the description in conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
In the figures which illustrate example embodiments of the invention,
FIG. 1
is a perspective view of a sheet feeder made in accordance with this invention,
FIGS. 2 and 2
a
are schematic side views of
FIG. 1
,
FIG. 3
is a perspective end view of a portion of the feeder of
FIG. 1
,
FIG. 4
is a schematic side view of another embodiment of this invention,
FIG. 5
is a schematic side view of yet another embodiment of this invention, and
FIG. 6
is a schematic side view of a further embodiment of this invention.
DETAILED DESCRIPTION
Referencing
FIGS. 1 and 2
, sheet handling apparatus
10
comprises an in-feed sheet feeder
12
, a batch sheet feeder
14
, and a downstream target, such as boxes
15
between flights of flight conveyor
16
.
The in-feed sheet feeder may be of any type that will feed sheets singly to batch sheet feeder
14
. As illustrated, in-feed sheet feeder
12
has a stack
18
of sheets
20
supported by sheet guides
22
arranged such that the bottom sheet contacts a feed belt
23
. A motor
26
is provided to rotate a feed wheel
24
. If feed belt
23
is circulating, rotation of wheel
24
through an arc will feed a single sheet downstream. Such an in-feed sheet feeder
12
is further described in U.S. Pat. No. 4,651,983 to Long, the contents of which are incorporated by reference herein.
The batch sheet feeder
14
feeds sheets in a downstream direction D from the in-feed sheet feeder
12
to conveyor
16
. The batch sheet feeder
14
has a lower endless conveyor
30
and an upper endless conveyor
32
forming a sheet feed path between them. The conveyors
30
,
32
are driven by a motor
28
. Motor
28
also drives feed belt
23
. As is apparent from
FIGS. 1 and 3
, each of these conveyors comprises a plurality of endless belts
30
B,
32
B. The lower conveyor
30
substantially parallels the upper conveyor
32
along an upstream first section
34
. The lower conveyor
30
then wraps around separating support rolls
36
,
38
to jog away from the upper conveyor
32
. The separating support rolls are mounted on a base
37
, as is a backstop
66
; the base allows the downstream position of the separating support rolls (and the backstop) to be adjusted. The separating support rolls define an upstream end of a downstream second section
40
of the batch sheet feeder. With this arrangement, any gap between the upper
32
and lower
30
conveyors at the first section
34
is smaller than the gap
42
between these conveyors at the upstream end of the second section
40
.
The upstream end of the lower
30
and upper
32
conveyors is supported by in-feed support rolls
44
,
46
, respectively. The downstream end of these conveyors is supported by exit rolls
54
,
56
, respectively. Exit rolls
56
,
58
are mounted so that their spacing can be adjusted to some extent by screws
57
,
59
. However, any gap between the exit rolls
54
,
56
should be significantly smaller than gap
42
at the upstream end of second section
40
. In consequence, the gap
42
between the lower
30
and upper
32
conveyors is largest at the upstream end of the second section
40
and reduces in size toward the downstream end of the second section
40
.
An adjustable support roll
60
bears against the upper conveyor
32
at the second section
40
. The adjustable support roll may be adjusted in a direction toward or away from the lower conveyor
30
in order to selectively adjust the size of the gap
42
between the lower
30
and upper
32
conveyors.
Separating support roll
38
is upstream of separating support roll
36
. The lower conveyor
30
wraps around a downstream side of separating support roll
36
and around an upstream side of separating support roll
38
so as to form an “S” shape in the downstream conveyor. (In the right hand side view of
FIG. 2
, this appears as a backwards “S” shape.)
A retractable gate
62
is positioned proximate the downstream end of the second section
40
to selectively block sheets from exiting the batch sheet feeder
14
. A pneumatic valve
74
provides air pressure to reciprocate the gate. The gate depends from a bracket
72
and a guide
70
(
FIG. 3
) maintains the gate
62
in its proper orientation. Side sheet guides
73
(
FIG. 3
) are provided upstream of the gate
62
.
With reference to
FIG. 3
, each of the exit rolls
54
,
56
may be an undulating roll. These undulating rolls parallel each other with the peaks
76
of the upper undulating exit roll
56
aligned with the troughs
78
of the lower undulating roll
54
. The peaks of each undulating roll have gently sloped crowns
80
. Each belt
30
B,
32
B of the conveyors
30
,
32
wraps around one of these crowns. However, in order to accommodate gate
62
, no belt wraps around the central peak of the upper undulating exit roll
56
. This configuration of the exit rolls
54
,
56
allows the lower conveyor to project to, or above, the level of the upper conveyor at the exit rolls
54
,
56
. Thus, optionally, there may be no gap at all between the lower and upper conveyors at the exit rolls. Furthermore, with this arrangement, the belts self-centre on the crowns
80
of the peaks
76
. Optionally, in-feed support rolls
44
,
46
may be similarly configured undulating rolls.
A visual attribute sensor
82
and a sheet sensor
86
are positioned along the first section
34
of the batch sheet feeder. The visual attribute sensor may be a colour sensor of the type that, when prompted, memorises the colour currently within its field of view. After memorising a colour, the colour sensor outputs a “match” signal whenever it is subsequently prompted to sense the colour within its field of view and the colour it sees is the same as the memorised colour. A suitable colour sensor operating in this fashion is the CZ-K
198
series RGB digital fiberoptic sensor manufactured by Kayence Corporation of Japan. The visual attribute sensor has a mount
84
that allows its transverse and downstream position to be adjusted. A batch sensor
88
is positioned along the second section
40
of the batch sheet feeder.
A processor
90
receives an output signal from each of sheet sensor
86
and batch sensor
88
. The processor is also coupled for communication with visual attribute sensor
82
. The processor outputs control signals to each of motors
26
and
28
and pneumatic valve
74
. The processor also receives batch demand signals on control line
92
.
Sheet handling apparatus
10
may be operated with visual attribute sensor
82
active or inactive. It is assumed first that processor
90
is loaded with an indication visual attribute sensor is inactive. The processor is also loaded with an indication of the number of sheets that are to be in each batch and a stack
18
of sheets
20
is loaded into sheet guides
22
. The downstream position of base
37
is then adjusted so that the length of gap
42
between backstop
66
and gate
62
is sufficient to accommodate the length of the sheets
20
that are in stack
18
.
The processor
90
may then accumulate a first batch of sheets at the second section
40
of batch sheet feeder
14
. To do so, the processor ensures gate
62
is blocking the exit of the batch sheet feeder by sending an appropriate activation signal to the pneumatic valve
74
. The processor then activates motor
28
in order to circulate conveyors
30
and
32
(and feed belt
23
) and motor
26
to rotate feed wheel
24
in order to feed sheets singly between the conveyors
30
,
32
. The conveyors
30
,
32
entrain the sheets and move them in the downstream direction D toward the gate
62
. As sheets
20
pass sheet-sensor
86
, “sheet sensed” signals are sent to the processor. This allows the processor to keep track of the number of sheets that have been fed. After this number reaches the previously loaded number of intended sheets in each batch, the processor stops motors
26
and
28
.
As each fed sheet passes separating support roll
36
, it drops into the gap
42
between the upper
32
and lower
30
conveyors and then continues downstream until stopped by gate
62
. Adjustable support roll
60
creates a bend in upper conveyor
32
. This causes sheets feeding past support roll
60
to bend—as illustrated by sheet
20
B in
FIG. 2
a
. Once the trailing edge of a bent sheet enters gap
42
, the sheet naturally begins to straighten out to lose its bend; this urges the trailing edge of the sheet downwardly, thereby reducing the risk of the next upstream sheet crashing into the trailing edge of the straightening sheet. Because of the enlarged gap between the upper and lower conveyors in the second section
40
, the frictional contact of the lowermost and uppermost sheets accumulated in section
40
with respective conveyors
30
and
32
is reduced sufficiently to avoid bruising or spindling the sheets. Adjustable support roll
60
may be adjusted in accordance with the size of a batch: the larger the batch, the larger the gap
42
so as to control the frictional force on the uppermost sheet accumulated in section
40
. Additionally, the spacing between exit rolls
56
,
58
can also be adjusted in accordance with the size of the batch to control the frictional forces on the batch.
Backstop
66
precludes the possibility of the trailing edge of a sheet becoming entrained in the short upstream run of the lower conveyor
30
as it loops back from roll
36
to roll
38
.
Once an entire batch is in gap
42
and the processor has stopped motors
26
and
28
(thereby stopping the conveyors
30
,
32
), the processor causes the gate
62
to be retracted. Optionally, the processor may then control motor
28
to move conveyors
30
,
32
slowly in order to advance the accumulated batch sufficiently so that the batch is between the exit rolls
54
,
56
, whereupon the processor again stops the conveyors
30
,
32
. (A rotary encoder associated with motor
28
can be used to allow the processor to know how far it has advanced the batch.) In this situation, the front of the batch is tightly held between the exit rolls
54
,
56
(but the trailing edge of the batch has not passed batch sensor
88
).
When the processor
90
receives a batch demand signal on line
92
, it activates motors
26
and
28
to again begins circulating conveyors
30
and
32
so that the batch exits to conveyor
16
through the exit rolls
54
,
56
. In this regard, with the upper surface of the lower conveyor belts
30
B positioned below the lower surface of the upper conveyor belts
32
B, the sheets in the batch will be forced to assume an undulated shape as they pass through the exit rolls. This enhances the frictional engagement of the batch of sheets with the conveyor belts
30
B,
32
B and thereby assists in ensuring proper feeding. (Where in-feed support rolls
44
,
46
are similarly configured, in-fed sheets may also be forced to assume an undulated shape that enhances frictional engagement and thereby assists in ensuring proper feeding.)
When the trailing edge of a batch passes batch sensor
88
, the batch sensor signals processor
90
. This prompts the processor to extend gate
62
to again block the feed path. With both motors
26
and
28
activated, a new batch is accumulated in the second section
40
of the batch sheet feeder. The operation then repeats as aforedescribed.
The adjustment mechanism for adjustable support roll
60
may be a manually operated mechanism or an actuator controlled by processor
90
. In the latter case, where the ready position of a batch (i.e., the rest position of the batch while a demand signal is awaited) is such that the trailing edge of the batch is upstream of roll
60
, once a batch reaches the ready position, the processor may lower roll
60
to engage the batch more securely. This will allow a batch to be more securely ejected. Once the batch has been ejected, the processor would retract
60
back to a position for accumulation of tire next batch.
Optionally, two adjustable support rolls (not shown) may be provided at the downstream position of gate
62
, one on either side of the gate. If these additional rolls are provided, they may remain in a retracted position while gate
62
blocks the feed path, but may extend to push the conveyor belts
30
B or
32
B with which they are associated closer together when gate
62
is retracted. These two adjustable support rolls may therefore assist in ensuring that the batch is positively fed to the exit rolls
54
,
56
after the gate has been retracted. Also, if the feeder is equipped with these additional adjustable support rolls, the spacing between the exit rolls
54
,
56
may be increased. The increased spacing between the exit rolls helps ensure that the exit rolls are not so tightly spaced as to jam a developing batch against the gate with a force that will spindle sheets in the batch.
In the special case where the processor is loaded with an indication that a batch comprises only a single sheet, the processor can permanently raise gate
62
and, where it can control the position of roll
60
through an actuator, can lower roll
60
so that the conveyors
30
,
32
beneath the roll will pinch a single sheet. The operation of feeder
14
would also differ in that processor would simply operate motors
26
and
28
until batch sensor
88
is interrupted by a single sheet. Thereafter, on receipt of a demand signal, the sheet interrupting the batch sensor would be ejected and feeding would resume until the next sheet interrupted the batch sensor
88
.
Optionally, motors
26
and
28
could be replaced by a single motor with an appropriate drive train to obtain a desired speed ratio between (slower moving) feed wheel
24
and conveyors
30
,
32
.
Optionally, the flight conveyor
16
could move substantially in downstream direction D, rather than transversely to this downstream direction as is shown in FIG.
1
. For example, with reference to
FIG. 4
, a conveyor
116
conveys target boxes
115
in a target downstream direction DT. Target downstream direction DT crosses downstream direction D at a batch insertion station where a batch
120
is inserted into an open top of a box
115
. In this regard, conveyor
116
may operate continuously and the batch sheet feeder
14
controlled so that it ejects batches at a speed matched to that of the conveyor
116
. As a further example, with reference to
FIG. 5
, a batch deflector
225
is added to the output end of batch sheet feeder
14
. A conveyor
216
conveys boxes
215
in a downstream direction DT that crosses downstream direction D at a batch insertion station. The batch sheet feeder
14
is controlled so that a batch is projected with sufficient speed to be inserted into the open top of a box
215
as it passes. Again, the speed of feeding batches may be controlled to match that of a continuously operating conveyor. Unlike drop table batch sheet feeders, there is no requirement to feed to a target only from directly above; also, the speed of feeding may be greater than what can be achieved by gravity. And unlike batch feeders that stack a batch directly on to a target, there is no need to stop the target while the batch is fed. It will be apparent that, in fact, if desired, batch sheet feeder
14
may feed batches at high speed. This allows the batch sheet feeder
14
to place batches onto, or into, targets that continuously move past the exit rolls
56
,
58
. Further, these targets may move in, or substantially in, the downstream direction D of the batch sheet feeder
14
.
FIG. 6
wherein illustrates alternate arrangement for the batch sheet feeder. Turning to
FIG. 6
wherein like parts have been given like reference numerals, batch sheet feeder
214
differs from batch sheet feeder
14
of
FIGS. 1
to
5
in that the downstream second section
40
is separate from the upstream first section
34
. More particularly, the upstream section
34
is defined by conveyors
130
,
132
which ride on rolls
44
,
250
, and
46
,
252
, respectively. And the downstream section
40
is defined by conveyors
230
,
232
which ride on rolls
270
,
54
, and
272
,
56
, respectively. A suitable drive train may operatively couple the conveyors of the upstream section with those of the downstream section. With separate upstream
34
and downstream
40
sections, batch sheet feeder
214
omits the separating rolls
36
,
38
of
FIGS. 1
to
4
and so the length of the downstream section
40
is not readily adjustable. In other respects, the batch sheet feeder
214
operates in the same manner as batch sheet feeder
14
of
FIGS. 1
to
5
with sheets feeding singly along the upstream section and dropping into gap
42
and accumulating as a batch.
In the batch sheet feeder
214
of
FIG. 6
, the upper conveyor
132
could be replaced with a stationary sheet guide.
Where the sheets of a batch are visually different, the visual attribute sensor
86
may be used to help ensure each batch is properly constituted. For example, each sheet of a batch may have a different pattern of colours. This could occur where, for example, each sheet of a batch is a different advertisement. For such batches, the visual attribute sensor
86
could be the aforedescribed colour sensor.
Typically, sheets of a batch are printed such that each batch has the same set of sheets (e.g., the same set of advertisements) in the same order. To verify such batches, an area of one sheet (the “target” sheet) of a model batch is selected that is coloured distinctly from the same area of all other sheets of the batch. The target sheet will have a certain ordinal position in the batch. The processor
90
is then prompted to advance sheets of the first batch until the target sheet from the first batch (i.e., the sheet in the first batch that is at the certain ordinal position) is at a given downstream position. Colour sensor
82
is then moved in its mount
85
so that its field of view is aligned with the selected area of the target sheet; the colour sensor is then locked in its mount in that position. With the selected area of the target sheet within the field of view of the colour sensor, the colour sensor is prompted to memorise the colour(s) of that area of the target sheet. The processor is also prompted to memorise the ordinal position of the target sheet in the batch.
Conveniently, the sheet sensor
82
sends a signal to processor
90
each time it senses (a leading or trailing) edge of a sheet (such that the processor counts one sheet after receiving two consecutive signals from sheet sensor
82
). In such case, the given downstream location of the target sheet can be defined as the position at which the sheet sensor
86
senses the leading edge of the target sheet.
After the processor has memorised the noted parameters (of colour and ordinal position), whenever a batch is fed, the processor monitors for the leading edge of the target sheet (i.e., the sheet at the memorised ordinal position) in the batch and prompts sensor
82
to capture the colour of the selected area of that sheet. Provided the target sheet is, in fact, the intended sheet, the colour sensor will output a “match” signal. On the other hand, if the target sheet is not the intended sheet, the colour of the target sheet at the selected area will not match the memorised colour. In consequence, the processor will not receive the expected “match” signal. This will cause the processor to flag the current batch as faulty so that appropriate action can be taken.
While the example visual attribute sensor
82
is a colour sensor, other visual attribute sensors may be used. For example, the visual attribute sensor may be a visual pattern sensor for sensing the visual pattern within its field of view in addition to, or instead of, the colour. For example, the sensor could include a camera (such as a CCD camera) and output a “match” signal only when the (coloured) pattern within the field of view of the camera matched a memorised pattern. Alternatively, where the sheets included bar codes, the visual attribute sensor could be a bar code reader. Also, instead of the visual attribute sensor being a separate component, the sensor could be a combination of a visual sensor, such as a camera (at the location of sensor
86
) and the processor
90
. That is, the processor could process signals from a camera in order to store an initial (coloured) pattern and compare it with a current pattern.
Optionally, a visual attribute of more than one sheet, or indeed of all sheets, of a batch may be memorised and used as a metric of comparison with corresponding sheets of future batches to identify faulty batches. As a further option, the last sheet in each batch may be provided with a visible end-of-batch indicia positioned so that it will be in the field of view of the visual attribute sensor as this last sheet passes the sensor. In such instance, the processor learns from the sensor that the last sheet of a batch has been fed. Consequently, there is no need for the processor to be pre-loaded with the batch size and, indeed, this size may change from batch to batch.
Adjustable support roll
60
could be replaced with an adjustable support abutment having a low friction surface that makes sliding contact with the upper conveyor
32
.
Other modifications will be apparent to those skilled in the art and, therefore, the invention is defined in the claims.
Claims
- 1. A batch sheet feeder comprising:an upstream first conveyor section arranged to convey sheets singly in a downstream direction to a downstream second conveyor section; said second conveyor section comprised of an upper second conveying belt and a lower second conveying belt forming a gap therebetween, said gap being largest at an upstream end of said second conveyor section and diminishing in size toward a downstream end of said second conveyor section; a gate positioned proximate said downstream end of said second conveyor section for selectively blocking sheets from exiting said second conveyor section; and an adjustable support for adjusting a portion of said upper second conveying belt from a first position away from said lower conveying belt to a second position toward said lower second conveying belt in order to selectively adjust a size of said gap.
- 2. The feeder of claim 1 including a sheet sensor positioned along said first conveyor section.
- 3. The feeder of claim 2 including a batch sensor positioned along said second conveyor section.
- 4. The feeder of claim 2 further comprising a visual attribute sensor having a field of view covering an area of said first conveyor section at a certain downstream location so as to sense an area of any sheet at said downstream location.
- 5. The feeder of claim 4 further comprising a processor receiving an output from said visual attribute sensor and said sheet sensor.
- 6. The feeder of claim 5 wherein said one of said processor and said visual attribute sensor has an input for prompting the memorisation of a visual attribute within said field of view of said visual attribute sensor.
- 7. The feeder of claim 5 further comprising a mount for said visual attribute sensor permitting adjustment of said visual attribute sensor in said downstream direction and transversely of said downstream direction.
- 8. The feeder of claim 6 wherein said processor is for determining an error condition based on a timing of receipt of visual attribute signals received from said visual attribute sensor and sheet sensing signals from said sheet sensor.
- 9. The feeder of claim 8 wherein said determining comprises counting sheets based on sheet sensing signals received from said sheet sensor.
- 10. The feeder of claim 9 wherein said processor determines said error condition if a memorised visual attribute is not detected when a count of sheets is at a pre-set count.
- 11. The feeder of claim 1 wherein a downstream end of said upper second conveying section is supported by an upper undulating roll and a downstream end of said lower second conveying section is supported by a parallel lower undulating roll such that peaks of said upper undulating roll are aligned with troughs of said lower undulating roll.
- 12. The feeder of claim 11 wherein peaks of each undulating roll have crowns.
- 13. A batch sheet feeder comprising:an upstream first conveyor section arranged to convey sheets singly in a downstream direction to a downstream second conveyor section; said second conveyor section comprised of an upper second conveying section and a lower second conveying section forming a gap therebetween, said gap being largest at an upstream end of said second conveyor section and diminishing in size toward a downstream end of said second conveyor section; a gate positioned proximate said downstream end of said second conveyor section for selectively blocking sheets from exiting said second conveyor section; wherein said upstream first conveyor section and said downstream second conveyor section are comprised of an upper endless conveyor and a lower endless conveyor, said lower conveyor substantially paralleling said upper conveyor along said first section, said lower conveyor jogging away from said upper conveyor at an upstream end of said second section so as to form said gap; at least two support rolls around which said lower conveyor wraps so as to cause said jogging away of said lower conveyor, wherein said at least two support rolls comprise a downstream support roll and an upstream support roll and wherein said lower conveyor wraps around a downstream side of said downstream support roll and around an upstream side of said upstream support roll and wherein said upstream support roll is upstream of said downstream support roll.
- 14. A batch sheet feeder, comprising:a lower endless conveyor, an upper endless conveyor arranged with respect to said lower conveyor so as to form a sheet feed path between said lower conveyor and said upper conveyor for feeding sheets in a downstream direction; said lower conveyor substantially paralleling said upper conveyor along an upstream first section, said lower conveyor jogging away from said upper conveyor at an upstream end of a downstream second section so as to form a gap between said lower conveyor and said upper conveyor at said second section that is larger than any gap between said lower conveyor and said upper conveyor at said first section; at least two support rolls around which said lower conveyor wraps so as to cause said jogging away of said lower conveyor, wherein said at least two support rolls comprise a downstream support roll and an upstream support roll and wherein said lower conveyor wraps around a downstream side of said downstream support roll and around an upstream side of said upstream support roll and wherein said upstream support roll is upstream of said downstream support roll.
- 15. The feeder of claim 14 wherein said second section gap is largest at an upstream end of said second section and reduces in size toward a downstream end of said second section.
- 16. The feeder of claim 15 further comprising an adjustable support for adjusting a portion of said upper conveyor toward and away from said lower conveyor, said adjustable support positioned between said at least two support rolls and a downstream end of said second section.
- 17. A method of feeding sheets, comprising:conveying sheets singly in a downstream direction to a conveyor section having an upper endless belt and a lower endless belt forming a gap therebetween, said gap being largest at an upstream end of said conveyor section and diminishing in size toward a downstream end of said conveyor section; pressing said upper endless belt toward said lower endless belt between said upstream end of said conveyor section and said downstream end of said conveyor section in order to form a bend in said upper endless belt such that sheets entering said gap bend so that as a trailing edge of a sheet enters said gap, said trailing edge is urged downwardly as said sheet naturally begins to straighten out.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2392237 |
Jun 2002 |
CA |
|
US Referenced Citations (17)
Foreign Referenced Citations (2)
Number |
Date |
Country |
1084977 |
Mar 2001 |
EP |
2000331221 |
Nov 2000 |
JP |