DE102016015729A1 - sheet feeder - Google Patents

Abstract

The invention relates to a sheet feeder for a sheet-processing machine, with a stacking table, on which a stack of sheets to be processed can be placed, with tools that can be brought into contact with the stack to separate the respective uppermost sheet from the stack and for processing in the machine, wherein on the stacking table an arch detector is arranged, wherein the sheet detector is able to distinguish whether the stack comprises one or more sheets, and to trigger a shutdown when the stack comprises only a sheet or a sheet and in that the tools, in addition to transport tools, include a stylus that is placeable under the topmost arc of the stack to hold a second uppermost arc on the stack during transport of the topmost sheet by the transport tools, and wherein the shutdown operation precludes stopping of the stylus base prior to stopping includes the transport tools.

Description

The invention relates to a sheet feeder according to the preamble of claim 1.

From the DE 10 2004 015 335 A1 a sheet-fed printing machine is known in which a detector is arranged on a belt table, are conveyed on the sheet to be printed by a sheet feeder to a printing unit, which is adapted to detect a multiple arc and the last arc of a scale flow and detection of a last sheet to stop the pressurization of the arc-promoting suction belts with negative pressure and in this way to ensure that the last sheet can be exactly aligned in the transport direction as the preceding when reaching marks of a feed table.

The US 2004/0164481 A1 discloses a sheet feeder for a sheet processing machine, comprising a stacking table on which a stack of sheets to be processed is placeable, with tools which are brought into contact with the stack to separate the respective uppermost sheet from the stack and for processing in the Transport away machine, wherein an arch detector is arranged on the stacking table

The US Pat. No. 3,785,287 A teaches by means of an electric switch at last bow off cylinder.

The invention has for its object to provide a sheet feeder.

The object is achieved by the features of claim 1.

The advantages achieved by the invention are, in particular, that on the one hand the placement of the sheet detector on the sheet stack itself and on the other hand, the ability of the sheet detector to differentiate between a single sheet and multiple sheets on the stack, a recognition that the stack will be used up soon is made possible immediately before this event occurs. Components of the sheet feeder or the printing press, which could be damaged by further operation without bow, can thus be stopped in time; At the same time, however, it is possible to prevent the sheet feeder from already stopping before the stack has been completely used up and any residual sheets remaining make it difficult to refill the stack.

In particular, the components that can be protected from damage include first transport tools that are movable between a sheet receiving position on the stack and a sheet release position remote from the stack. Such transport tools must be lightweight, so they do not damage the sheet to be processed when contacting; At the same time, however, the lightweight construction increases the risk of damaging the transport tools when they collide against the stacking table or a pallet on which the stack has been loaded onto the stacking table rather than against a sheet of the stack, because the stacking table needs to be stacked being heavy and unyielding, and since the pallet is not part of the sheet feeder, there is no certainty that knocking against it will be possible without damaging the tools. To protect the first transport tools, therefore, the shutdown operation should include stopping them after releasing the last sheet in the sheet release position and re-reaching the sheet receiving position.

The transport tools may in particular be vacuum-actuated vacuum cleaner, in particular vacuum cleaner, which are proven for lifting individual sheets of a stack, however, tear in contact with an uneven or sharp-edged surface or buckling along their edges abutting the bow and thereby can be leaking.

Second transport tools, typically also suckers, in particular transport suction, can be provided for further transporting the sheet after release by the first transport tools. So that the last sheet of a stack can still be processed correctly after being picked up by the first tools, the shut-off process should include the stopping of the second transport tools only after the first transport tools.

As a further tool, a feeler foot can be provided in a manner known per se, which can be placed under the uppermost sheet of the stack, in order to keep a second uppermost sheet pressed against the stack during the removal of the uppermost sheet by the transport tools. As part of a shutdown of the button foot should be expediently stopped before the transport tools to prevent even during recording and Abtransports of the last bow, a striking the button foot to the stacking table.

Especially in order to prevent a strike of the button foot to the empty stacking table, it is important that the detector does not respond until the stack is completely used up, but is already able to detect if there is only one sheet left located in the stack.

The turn-off operation may also include outputting a turn-off signal to the sheet-processing machine, such as to stop printing units when sheets are out of sheet, or to relieve printing gap bounding cylinders from each other to prevent an impression cylinder from being contaminated by ink when it is not more is covered by a sheet to be printed.

Typically, the detector unit is an electronic camera that images the projected light distribution onto an array of photosensitive sensors.

To keep the evaluation simple, it is preferable that the light distribution is a line.

The light distribution projected onto the stack should overlap with a surface area where the transport tool contacts the stack. Thus, the height at which the transport tool must come into contact with the stack surface when picking up a sheet can be precisely estimated in advance and taken into account in controlling the movement of the transport tool.

If multiple transport tools are provided for receiving a sheet from the stack, the light distribution projected onto the stack should overlap with the surface areas contacted by both transport tools so that the height at which they come into contact with the sheet can be estimated for both transport tools.

If the plurality of transport tools for receiving a sheet are independently adjustable in height, it can be ensured even in the case of unevenness of the stack surface, that the transport tools get to grasp the sheet surface at the same time. This is particularly helpful when the transport tools are parallel with vacuum applied suction cups.

When the transport tools successfully grasp and lift a sheet, it also results in a displacement of the light pattern projected onto the surface of the sheet. If such a shift does not occur, if the transport tools have carried out the movement necessary for lifting a sheet, then either the stack has been used up or the lifting has failed for another reason. In one case as in the other case, the bow detector should be arranged to stop the button foot in such a case and prevent it from either resting on the table or a pallet lying on the table or the bow that should have been lifted on the table Holding piles.

For this purpose, the transport tools and the feeler should be independently movable, either by their own drives are assigned to them or they are connected to a common drive via couplings.

The invention also relates to a sheet-processing machine, for example a printing machine, in particular a sheet-fed press, with a sheet feeder as described above, in particular a sheet-processing machine in which movable components can be switched off by a shutdown signal of the sheet feeder.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below.

Show it:

1 a schematic representation of a sheet feeder and a sheet feeder of a sheet-fed printing machine in side view;

2 a schematic perspective view of a sheet stack in the sheet feeder and aligned on the sheet stack detector;

3 an image taken by a camera of the detector.

In the 1 partially illustrated sheet-fed printing machine comprises a sheet feeder 01 , a belt table 02 , a bow plant 03 and following the bow system 03 several works not shown here in detail, such as a printing unit 04 , Coating unit, drying plant, calibration factory or the like.

In the sheet feeder 01 is a stack 09 , for example, a sheet pile 09 on a stacking table 10 placed. The stacking table 10 is by means of a lifting device 11 height adjustable to the top bow 06 of the sheet pile 09 regardless of the number of sheets in the stack 09 on a fixed or slightly changeable, for the transfer of the bow to the belt table 02 to keep suitable height. In the presentation of the 1 lie the bows of the pile 09 directly on the stacking table 10 ; between stacks 09 and stacking table 10 but could also be a pallet on which the stack 09 to the stacking table 10 transported and deposited on it and whose height is unknown, so that from the position of the lifting device 11 not on the height of the pile 09 or the number in the stack 09 contained bow can be closed.

A front stop 16 defines a vertical plane in which the leading edges of the arc of the sheet pile 09 are positioned. A bow flap 17 is a flap shaft 18 between the in 1 shown, the front stop 16 rectilinearly upward extending position counterclockwise pivoted in a substantially approximately horizontal position, in which they transport the sheet to the downstream belt table 02 supported.

The sheet feeder 01 covers, here in a sheet separator 14 summarized, various tools for disassembling the stack 09 in individual sheets and for transporting the sheets to the printing units 04 and other works of the sheetfed press.

These tools include on the one hand several so-called suckers 12 , especially as a vacuum cleaner 12 trained tools 12 , in particular transport tools 12 moving over one in the transport direction 44 the bow rear edge 05 of the pile 09 arranged and movable in a substantially vertical direction. The vacuum cleaner 12 each one down, to the stack 09 open suction cup made of a flexible plastic, which are connected at its upper end with a common vacuum source. The vacuum must be sufficient to secure the suction cups to the stack 09 bow to be lifted 06 but he must not be so strong that he has the bow 06 pulls into the suction cup and thereby deformed. If not all the suction cups of the vacuum cleaner 12 abutting a bow to be lifted, the air flow over an uncovered suction cup can cause that in the other suction cups necessary for lifting vacuum is not reached. For a safe lifting of a bow 06 It is therefore important that all vacuum cleaners 12 to come in contact with him at the same time. For this purpose, every vacuum cleaner 12 with the help of its own drive, in particular a linear actuator, relative to the sheet separator 14 be mobile; Preferably, a common frame in which all the extraction sucker 12 held by means of a fast, powerful main actuator relative to the sheet separator 14 movable to the bow 06 from the pile 09 suck on and along the edge 05 lift, and to remove bumps at the top of the pile 09 balance and simultaneous contact of all vacuum cleaners 12 with the bow to be lifted 06 ensure the vacuum cleaner 12 adjustable with the help of auxiliary actuators relative to the frame, the latter may be slower and have a smaller stroke than the main actuator.

Another tool of the sheet separator 14 is as a button foot 15 trained tool 15 that is between one in 1 shown, along the edge 05 on the pile 09 pressing stop position and one opposite the stop position and raised against the sheet transport direction behind the edge 05 staggered rest position is movable. In the stop position the button foot becomes 15 placed when the topmost bow 06 of the pile 09 from the vacuum cleaners 12 along the back edge 05 has been raised to prevent underlying bow of the stack 09 be whirled up, if one behind the edge 05 at the height of the top of the stack 09 arranged blowing device 19 Air in one between the raised bow 06 and the rest of the stack 09 open gap 07 blows.

Furthermore, at the sheet separator 14 sucker 13 , especially as a transport vacuum 13 trained tools 13 , in particular transport tools 13 provided that a predominantly vertical movement in or against the sheet transport direction 44 To run. The transport suckers 13 wise as the vacuum cleaner 12 flexible suction cups on after lifting the vacuum cleaner 12 be subjected to negative pressure to the raised arc 06 to attract. At the same time the vacuum cleaner 12 no longer subjected to negative pressure, so they bend 06 release. The blower 19 in the gap 07 blown air lifts the bow 06 on its entire surface from the pile 06 and forms under the arch 06 an air cushion on which the bow 06 , driven by the horizontal movement of the transport suction 13 , over the then swung in the horizontal sheet flap 17 on the tape table 02 is pushed.

The sheet feeder 01 Subordinate belt table 02 is in the embodiment as Saugbändertisch 02 educated. It preferably comprises two rollers 20 ; 21 , For example, a drive roller 20 and a guide roller 21 , Between the two rollers 20 ; 21 extends a one- or multi-part table top 22 , The tabletop 22 forms the multiple perforated top of a suction box 23 , The drive roller 20 and the guide roller 21 are from at least one conveyor belt 24 entwined, like the tabletop 22 it is often broken through, so it is not on the tabletop 22 is firmly sucked, but a bow to the conveyor belt 24 is sucked.

The rotational speed of the conveyor belt 24 is generally smaller than the ratio of edge length of the arc 06 at the cycle time of the sheet separator 14 , so if the transport suckers 13 start a new arc 06 over the bow flap 17 slide, the previous sheet has not completely passed. So will on the conveyor belt 24 a submerged stream formed by arches in which the number of each other overlapping arc is variable depending on the rotational speed, edge length and cycle time.

The bow plant 03 to which the sheets of the circulating conveyor belt 24 be funded, includes a feed table 26 and, at one in the sheet transport direction 44 rear edge of the feed table 26 , Attacks 27 who from their in 1 shown, the conveying path of the bow blocking stop position are retractable to one of the stops 27 adjoining sheet the way to the subsequent printing unit 04 to release from the in 1 a transfer drum 29 , an impression cylinder 30 and a blanket cylinder 31 are shown.

An arch detector 32 , the z. B. on an underside of the sheet separator 14 can be arranged comprises at least one projection unit 33 , an electronic camera 34 and an evaluation unit 35 , in particular image evaluation unit 35 ; 2 shows an embodiment in which the image evaluation unit 35 several projection units 33 ; 33 '; ..., for example light sources 33 ; 33 ' , ... and cameras 34 ; 34 '; ... are assigned along the edge 05 are distributed to the top bow 06 on the stacking table 10 lying stack 09 over much of the back edge 05 across, preferably over its entire length and slightly beyond.

As light sources 33 ; 33 '; ... for the projection units 33 ; 33 , ... come in particular laser, z. As diode lasers, into consideration, which emit a focused light beam from a cylindrical lens or a rotating mirror in a plane 36 , in particular Strahlebene 36 is fanned out. In the case shown here, the plane runs 36 oblique to a surface normal of the arch 06 or the stacking table 10 while the optical axes 37 ; 37 '; ... the cameras 34 ; 34 '; ... lie parallel to the surface normal. Conversely, the surface normal in the ray plane could be the same 36 run and the optical axes 37 ; 37 '; ... be oriented to it at an angle, or it could be both the radiation planes 36 the projection units 33 ; 33 '; ... as well as the optical axes 37 ; 37 '; ... the cameras 34 ; 34 '; ... lie obliquely to the surface normals. In the one case as in the other case appears from the perspective of a camera 34 ; 34 '; ... and how in 3 shown a line 38 along which the Strahlebene 36 on the bow 06 hits, laterally offset against a line 39 along which the Strahlebene 36 on the stacking table 10 or the surface of a pallet next to the stack 09 meets.

If as shown here both lines 38 ; 39 are visible in the image, the offset d between the two is measurable on the basis of this one image and is taken by the image evaluation unit 35 evaluated.

The on the bow 06 projected lines 38 ; 38 '; ... may deviate from a straight-line course if the topmost bow 06 because of air bubbles in the stack 09 , not completely flat. A section 40 the line 38 in 3 corresponds to a survey caused by such air entrapment. The projected lines 38 . 38 ' , ... several light sources 33 ; 33 '; ... can from the evaluation unit 35 to a contiguous height profile of the stack 09 be merged for each of the several along the edge 05 arranged vacuum cleaner 12 . 12 ' the height of an immediately underlying surface area 42 ; 42 '; ... of the bow 06 indicates. The evaluation unit 35 controls the above-mentioned actuators of the individual vacuum cleaner 12 ; 12 '; .... according to the detected height differences between the surface areas 42 ; 42 '; ... so that all vacuum cleaners 12 ; 12 '; ... equidistant from the opposite surface areas 42 . 42 ' and if the frame 43 together with the vacuum cleaner 12 ; 12 '; ... is lowered to a bow 06 to suck in, all vacuum cleaners 12 ; 12 '; ... at the same time as the bow 06 get in touch.

If after contacting the vacuum cleaner 12 ; 12 '; ... with the bow 09 the frame 43 with the vacuum cleaners 12 ; 12 '; ... is raised, this leads to a strong shift of the projected lines 38 ; 38 '; ···· If the evaluation unit 35 after lifting the vacuum cleaner 12 ; 12 '; ... no shifting of the lines 38 ; 38 '; ... recognizes the height of the stack 09 but not yet zero, then is the lifting of the bow 06 failed, and the evaluation unit 35 causes an immediate stop of the tools 12 ; 13 ; 15 the sheet separator 14 as well as, at the latest after all correctly from the stack 09 transported away sheets are printed and the feed table 26 is empty, a stop of the printing unit 04 and all other works of the printing press.

If the remaining sheet count is not greater than 1, then the raised sheet is 06 the last of the pile 09 , In this case, the evaluation unit stops 35 the movement of the button foot 15 before this the stacking table 10 touched, and the movement of the vacuum cleaner 12 ; 12 ' ... after they have reached a raised position in which the bow 06 to the transport suction 13 is handed over. The blowing device 19 is activated again, and the transport suckers 13 carry out one last cycle of movement to the last bow 06 still on the belt table 02 eject. Only when pushing out the bow 06 has started, actually comes from the stack otherwise 09 covered surface of the stacking table 10 in the field of vision of the cameras 34 ; 34 ' , .... at this time are the button foot 15 and the vacuum cleaner 12 ; 12 '; ... through a Hitting the stacking table 10 Could be damaged, but already in peace.

The output to the printing machine shutdown signal causes a stop of the printing units 04 , immediately after the last, only after the output of the signal still from the stack 09 removed bow 06 has gone through this and has been printed properly.

LIST OF REFERENCE NUMBERS

01

sheet feeder

02

Belt table, suction belt table

03

sheet feeder

04

printing unit

05

Edge, rear

06

bow

07

gap

08

09

Pile, bow pile

10

stacking table

11

lifter

12

Tool, transport tool, vacuum cleaner, vacuum cleaner

13

Tool, transport tool, vacuum cleaner, transport vacuum cleaner

14

sheet separator

15

Tool, button foot

16

frontgauge

17

bow flap

18

flap shaft

19

blower

20

Roller, drive roller

21

Roller, guide roller

22

table sheet

23

suction box

24

conveyor belt

25

26

feed table

27

attack

28

29

transfer drum

30

Impression cylinder

31

Blanket cylinder

32

sheet detector

33

Projection unit, light source

34

camera

35

Evaluation unit, image evaluation unit

36

Level, radiation level

37

Axis, optical

38

line

39

line

40

section

41

42

surface area

43

frame

44

Sheet transport direction

12 '

Tool, vacuum cleaner, vacuum cleaner

33 '

Projection unit, light source

34 '

camera

37 '

Axis, optical

38 '

line

42 '

surface area

d

offset

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004015335 A1 [0002]
• US 2004/0164481 A1 [0003]
• US 3785287 A [0004]

Claims (11)

Sheet feeder ( 01 ) for a sheet-processing machine, with a stacking table ( 10 ) on which a stack ( 09 ) of sheets to be processed ( 06 ) is placeable with tools ( 12 ; 13 ; 15 ), with the stack ( 09 ) are brought into contact with the uppermost sheet ( 06 ) from the stack ( 09 ) and transported away for processing in the machine, wherein at the stacking table ( 10 ) an arc detector ( 32 ), characterized in that the arc detector ( 32 ) is able to distinguish whether the stack ( 09 ) one or more sheets ( 06 ) and trigger a shutdown when the stack ( 09 ) only one more sheet ( 06 ) or no bow ( 06 ) and that the tools ( 12 ; 13 ; 15 ) next to transport tools ( 13 ; 12 ) a button foot ( 15 ) located under the topmost arc ( 06 ) of the stack ( 09 ) is placeable during the removal of the top sheet ( 06 ) by the transport tools ( 12 ; 13 ) a second highest sheet on the stack ( 09 ) and that the switch-off process, the stopping of the button foot ( 15 ) before stopping the transport tools ( 13 ) includes. Sheet feeder according to claim 1, characterized in that the tools ( 12 ; 13 ; 15 ) first transport tools ( 12 ) between a sheet receiving position on the stack ( 09 ) and one from the pile ( 09 ) are movable, and that the switch-off process, the stopping of the first transport tools ( 12 ) after releasing the last sheet in the sheet release position and re-reaching the sheet receiving position. Sheet feeder according to claim 2, characterized in that the tools ( 12 ; 13 ; 15 ) second transport tools ( 13 ) for further transporting the sheets ( 06 ) after release by the first transport tools ( 12 ) and that the switch-off process, the stopping of the second transport tools ( 13 ) after the first transport tools ( 12 ) includes. Sheet feeder according to one of the preceding claims, characterized in that the switch-off comprises the outputting of a switch-off signal to the sheet-processing machine. Sheet feeder according to one of the preceding claims, characterized in that the sheet detector ( 32 ) a projection unit ( 33 ; 33 ' , ...) for projecting a light distribution onto the stack ( 09 ). Sheet feeder according to claim 5, characterized in that the light distribution is a line ( 38 . 38 ' ). Sheet feeder according to claim 5 or 6, characterized in that on the stack ( 09 ) projected light distribution with a surface area ( 42 ; 42 ' , ...) overlaps where the transport tool ( 12 ; 12 ' , ...) the stack ( 09 ) touched. Sheet feeder according to claim 7, characterized in that a transport tool ( 12 ; 12 ' , ...) to record a sheet ( 06 ) from the stack ( 09 ) are provided and on the stack ( 09 ) projected light distribution with that of both transport tools ( 12 ; 12 ' , ...) touched surface areas ( 42 ; 42 ' , ...) overlaps. Sheet feeder according to claim 7 or 8, characterized in that several transport tools ( 12 ; 12 '; ...) to record a sheet ( 06 ) from the stack ( 09 ) are independently adjustable in height. Sheet feeder according to claim 1 or claim 5 or claim 6 or claim 7, characterized in that the sheet detector ( 32 ), the button foot ( 15 ) when, in conjunction with a movement of the transport tools ( 12 ; 12 '; ...) expected movement of the light distribution is absent. Sheet feeder according to claim 10, characterized in that the button foot ( 15 ) and the transport tools ( 12 ; 12 '; ...,) are independently movable.

Images