JPS6061262A - Gearless driving flexographic press - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to rotary printing presses, and in particular to the registration of such presses.

Regarding n).

If there is accurate registration of the position of the printing master or plate and the medium on which it is printed, the printing press will only give acceptable results. In various types of printing plates, there are other components that must also be maintained in precise registration with the printing master, such as blankets in rotary printing presses.

Traditionally, rotary printing presses have required precise transmission systems to enable the register of the rollers once installed, and there have also been limitations as to the accuracy with which the registration of the print can be adjusted. This is because the smallest incremental change in registration is the difference between the print master carrier, the regular plate cylinder, and the printed media carrier, the normal pressure cylinder.
r) to the pitch of the transmission device. A subsidiary problem arising from this case is that the ``make ready'' applied to the cylinder below the cylinder and/or plate is
J or "Packing sheet (backing 5h
eet) J must be precisely controlled.

This is because small variations in the radial spacing of the plate surface from the axis of rotation of the plate cylinder cannot be corrected to an accuracy finer than the pitch of one tooth of the transmission.

Traditionally, the task of assembling printing plates for precise printing registration involves correcting the surface speed of the printing plate and the printed media supported on the pressure cylinder for maintained printing registration. In order to be able to do this, it was necessary to accurately determine this 16" radial distance from the plate cylinder to the plate surface.

For effective printing, some rolling surfaces must always be in same-part contact with each other, and the contact between all rolling surfaces must be [scrub-free (scr.
(7) It should be a pure rolling contact.

Accordingly, one aspect of the invention is to provide a plate cylinder, a rotating support for the material to be printed, a second motor driving said support for the material to be printed, and a motor for driving said first and second The position of the plate of said plate cylinder with respect to said rotary support can be controlled precisely by controlling the rotational position of said plate cylinder with respect to said rotary support without requiring any mechanical interconnection between said plate cylinder and said support. A rotary printing press is provided, comprising: control means for ensuring synchronization of the rotary printing press;

When the printing press is a multicolor printing press and a plurality of different plate cylinders, each supporting a different color, must be registered very precisely with respect to the images printed by the other plates, The aforementioned problem becomes very serious.

A second aspect of the invention provides a rotating support for the material to be printed, a plate cylinder capable of supporting a plate over a portion of its cylinder surface for rolling contact in the nip of image transfer; a first motor that drives the cylinder; a second motor that drives the rotary support;
a motor and control means for controlling the position of the plate cylinder with respect to the rotating support, the control means maintaining a positional relationship at a constant surface speed of the plate cylinder over a first sector of rotation of the plate cylinder; death,
and at the end of the first sector of one rotation of said plate cylinder and said first sector in the next successive rotation of said plate cylinder.
To change the time delay between the start of a sector,
A rotary printing press is provided, characterized in that the printing press is effective for varying the speed of the forme cylinder over a second sector of rotation of the forme cylinder.

The invention will be further described with reference to the accompanying drawings.

Referring to FIG. 1, a continuous web of material to be printed, for example a continuous web of plastic packaging material (not shown)
A pressure cylinder 1 is shown supporting the .

A continuous plastic web is printed in at least two colors. The drawing shows a plate cylinder 2 carrying a plate 3 applicable to one of these colors. The drawing also shows the ink roller 4, which applies plate 3 ink. Preferably, an anilox roller is shown.

In a conventional rotary printing press, the plate cylinder 2 is a pressure cylinder (rotatable around a rotating shaft 5a in FIG. 1).
The anilox ink roller 4 is mechanically connected by a transmission to the main shaft 5 of the plate cylinder 2.
to provide scrub-free contact between the finely engraved anilonx roller and the resilient flexographic printing plate 3. The plate cylinder 2 can be separated from contact with the pressure cylinder l for the purpose of changing or accessing the components of the printing press, and the anilox ink roller 5 can, for example,
The arrangement is such that it can be separated from the plate printer 2 in order to stop the supply of ink to the plate 3 during operation or during the process of changing plates when assembling the machine for printing. . It is still possible according to the invention to be able to separate the forme cylinder 2 from the pressure cylinder 1 and the ink roller 4 from the forme cylinder 2.

However, instead of the conventional transmission between the pressure cylinder 1 on the one hand and the ink roller 4 on the other hand, the rotary printing press according to the invention uses three precisely controlled drive motors for each revolution. Connect to components.

The pressure cylinder l is thus rotated by its electric drive motor 6. This electric drive motor 6 can be drivingly engaged with a toothed pulley 7 of a drive shaft 5F of the pressure cylinder via a belt 8 with a thread. The forme cylinder 2 is in this case directly driven by its own digitally controlled electric motor 9 on the forme cylinder drive shaft 10-1, and the ink roller 4 is likewise driven by its own digitally controlled electric motor 9 on the ink roller drive shaft 12. It is directly driven by a digitally controlled electric motor 11.

Early opening mechanical coupling 13 to allow easy removal and replacement of the plate cylinder 2 and ink roller 4
are in this case provided on drive shafts 10 and 121- along with drive motors 9 and 11.

At each end of the plate cylinder drive shaft 10 there is a respective booking carrier 14. The booking carrier 14 is rotated by the rotation of the pressure cylinder l by the lead screw 15 rotated by the steppani motor 16.
5a and away from it.

Similarly, there is a respective booking carrier 17 at each end of the ink roller drive shaft 12. The printing carrier 17 is connected to the plate cylinder drive shaft 1 by means of a lead screw 10 driven by a stepper motor 19.
0 rotation axis and away from it.

The improvement according to the invention controls the rotational speed and rotational position of the motors 9 and 11 with respect to the rotational speed and rotational position of the pressure cylinder 1 (with reference in this case to the angular position and speed of its drive motor 6). For this purpose, a master control device, schematically illustrated as control device 20 in this case, is required. Controller 20 also controls the operation of "booking" stepper motors 16 and 19. The control connections between the control device 20 and the various motors 6.9.11.16 and 19 are schematically illustrated at 21 in FIG.

Each of the drive motors 6.9 and 11 is equipped with an encoder or "position resolver".
) is combined with J. This position resolver provides an accurate indication of the rotational position of the motor shaft and generates pulses which are applied to the control device 20 which in turn - Make it possible to guarantee accurate registration of the mutual positions of the ink rollers 4.

Booking carrier 14 for Bk cylinder 2
and feedback of the position of the carrier 17 for the ink rollers 4 is provided by a proximity detection system (proximi
ty detection system) 22 and also a proximity detection system 23 for the ink roller booking number carrier 17. The proximity sensor 23 of the ink roller's booking carrier 17 indicates that the carrier 17 is the printing cylinder's booking carrier 17.
Detecting when the carrier 14 reaches the vicinity of the upright portion,
A proximity sensor 22 in the plate cylinder booking gear 14 then senses when the gear 14 approaches an upright portion (not shown) of the machine frame 24.

Control device 20 preferably includes a microprocessor. This microprocessor has three motors 6
．． 9 and 11, and also in response to a print advance or "print retard" given by the operator. , making it possible to vary the rotational positional relationship.

This microprocessor also controls the so-called "decking" J movement of the deck of the plate cylinder defined by the carrier 14 and the deck of the ink roller defined by the carrier 17 in the "booking" step 7.・Motor (s
teppernotor) l'6 and 19 can be activated separately.

Such position response and maintenance control systems are well known in the art and the detailed circuitry thereof does not form part of the present invention. For example, similar circuits for precisely controlling the position of movable elements are disclosed in the following U.S. patents: U.S. Pat. No. 4,090,116 (
D. L. Lippitt, published May 16, 1987)
, U.S. Pat. No. 4,099,107 (J. Eder, 1
7 yl 4 E1, published in 1978), US Patent No. 4,
344.

127 inches (G, H, Mc Daniel, 1982.8
No. 4,357,561 (V.R. Fenci, No. 211, Nov. 1982)
.

For the sake of completeness, the following US patent specification may be mentioned which shows the use of electronic position control in printing systems: US Pat. No. 4,377.847 (R,A,Da
niel et al, published March 22, 1983)
, U.S. Patent No. 4,277.191 (G.W. Davi
et al., published July 7, 1981) and U.S. Pat. No. 4,114,750 (H.S. Baecke
T, al., published September 1911, 1978).

Surprising features of the invention are as follows.

That is, the precise alignment of the rotary components of the printing press, in this case represented by the pressure cylinder l, the plate cylinder 2 and the anilox ink roller 4, simply drives these various rotary components. This can be achieved and maintained by using the electronic control unit 20 of the motors 6.9 and 11. The cost of supplying a conventional transmission of sufficiently high quality to withstand rapid wear during use of the printing press, and the precise registration of the plate cylinder 2 with respect to the pressure cylinder l when the plate cylinder returns after printing. In order to achieve this, and also if possible to vary the gear ratio when installing plate cylinders with different radial dimensions, the necessary front losses are controlled by the control device 20 and by the plate cylinder 2 and the ink rollers. 4 duplicated drive motors 9 and 11 save.

Precise positional synchronization of the forme cylinder 2 and ink roller 4 with respect to the pressure cylinder 1 ensures that the forme cylinder 2
After removal from its printing position, the necessary registration is maintained by the control device 20 so that the plate cylinder can be restored to printing without the need for reregistering the printing press; It can also be seen that a scrub-free m-rolling contact between the finely engraved ink-bearing anilox ink roller 4 and the elastic plate 1/xo printing plate 3 on the plate cylinder is ensured.

The use of separate stepper motors 1-16 and 19, controlled by a control device 20, for printing the ink roller 4 and the form cylinder 2 makes it possible to improve the inking system of a multicolor printing press with respect to a common pressure cylinder 1. and the control device 2o can signal the simultaneous booking of all the plate cylinders, which means that all colors return simultaneously during printing. This saves considerable time in the booking process compared to manual booking. In manual booking, the operator carefully positions each plate cylinder (by alignment of the gear teeth of a conventional printing press) at a precise spacing from the axis of rotation 5a of the pressure cylinder and in precise angular alignment. Must-have.

Additionally, virtually simultaneous redecking of all colors allows each of the plate cylinders to
m) to provide on-the-run registration of the printing, and subsequently the individual plate cylinders 2
Achieving precise registration by adjusting the position of
It is well within the capabilities of the designer of controller 20. In order to ensure a "scrub-O-free" rolling contact between the ink rollers 4 and the plate 3 during such "on-the-fly" printing registration adjustments, the controller 20 adjusts to changes in the position of the plate cylinder. It must be possible to change the rotational position of the ink roller responsively (in proportion to the diameters of the ink roller 4 and of the form cylinder 2).

The registration of the print can also be achieved by manually setting cylinders 1 and 2 while stationary and (if necessary) by adjusting the control device 20 before restarting the press. When the rotation of cylinders 1 and 2 resumes, it can be ensured that the mutual rotational position of cylinders 1 and 2 provides a pure rolling contact with precise printing registration in their circumferences.

Another advantage of the system according to the invention is that the repetition length re
The conventional limit on the minimum incremental change in registration (peat length) no longer exists.

Traditionally, mechanical limitations in the pitch of the gear teeth have precluded fine tuning of the repeat length (so that printing plates can be stacked to large diameters and therefore large circumferences), but motor 6. If the number of pulses generated per revolution of 9 and 1 is large enough, it is easy to adjust the variation virtually infinitely, and the pulses from the various motors by the operator providing suitable input signals to the controller 20. It only requires a simple change in the multiplication ratio of the correlation.

Also, fine adjustment of printing is facilitated. This is because fine adjustment (to accuracy smaller than l-tooth pitch) conventionally involved axial repositioning of the helical transmission driving the plate cylinder, but according to the present invention, it simply adjusts the speed of the plate cylinder. Such adjustment was made possible by temporarily changing and repositioning it with respect to the pressure cylinder by the necessary increments.

Further advantages of the system according to the invention are: (a) The change of plate cylinders is very rigid.

This is because conventional plate shillings must be equipped with a transmission device that is common to all existing plate cylinders of a given size, and the transmission device must be installed before the plate cylinder is installed in the printing press. It didn't happen (
(b) upon cleaning the transmission and ensuring realignment of the transmission and returning the plate cylinder to the pressure cylinder-L;
Since it is unnecessary to ensure realignment of the conductor, the time for cleaning the machine (e.g. to change the ink color) is reduced: (C) Transfer of the machine to the conductor The problem of providing protection is eliminated: (d) Due to the very fine speed ratio adjustment possible by the electronic control unit 20, small variations occurring in the plate/plate cylinder combination can be compensated for, so that printing Changing the thickness of the plate and the thickness of the support sheet of the plate cylinder 1- is easy; and (e) the "chatter pattern" in the printed product caused by the resonance of the conducting device.
' occurrence, and also the overall vibration level in the printing press is reduced. This elimination of vibrations in the transmission further reduces the wear of the bearings and also of other relevant components of the machine, which affect the positioning and movement of the forme cylinder and/or the ink roller.

Due to the ease of very fine adjustments, very small changes in the diameter of the forme cylinder can be compensated for, for example after regrinding of the forme cylinder, so that the useful life of a given forme cylinder can be Use with a printing machine according to the invention can be extended considerably.

FIG. 2 shows the functionality of any equipment present in the printing press of FIG. 1, in which case the control device 2o is of a suitable type.

In any case, the explanation of
The controller 2o is capable of maintaining and/or restoring registration by small changes in the rotational speed of the plate cylinder 2 and the ink roller, assuming that the rotational speed of the plate cylinder 2 and the ink roller are substantially uniform throughout each cycle. there were.

Using any of the features illustrated in FIG.
The positional relationship of the form cylinder 2 with respect to 1 only needs to be maintained during the rolling of the sector AB of the form cylinder past the printing nip. During this rolling action, first of all the main design is printed on the medium to be printed in contact with the first version or the first version area 3a, and then after there is a gap corresponding to the sector BA, the auxiliary design is printed. The plate or plate area 3b prints a small panel at the edge of the media to be printed (e.g. a "registered trademark" is printed on the edge of the bag, or alignment marks on an optical film are detected by a photoelectric transducer). (for example, a series of plastic packaging bags).

While the main panel is printed from the plate or plate area 3a and the auxiliary panel is printed from the auxiliary plate or plate area 3b, there is no precise registration of the position of the plate cylinder 2 and the medium to be printed. Not, of course, in the case of multicolor printing presses.

There must be precise registration of the other plate cylinders used and the media being printed. however,
While the sector BA is rolled past the printing nip, no printing takes place and there is no relief printing plate area across the sector BA, so that the speed of the plate cylinder 2 can be varied as required.

This possibility of changing the speed increases the repetition length, i.e. the distance of the printing material between two successive images of either part of the plate or plate part 3a or 3b, and therefore the distance printed by the plate or plate part 3a. Main panel and plate or plate part 3b
change the spacing between the auxiliary panel printed by
By increasing the rotational speed of the plate cylinder 2 over the sector BA to reduce the repetition length, or by decreasing the rotational speed of the printing cylinder 2 over the sector BA to increase the repetition length, it is possible to , is particularly useful. However, the rotational speeds must be precisely synchronized when sector AB is in the nip.

Therefore, to facilitate any repeat length variations illustrated in FIG. If it is not possible to maintain precise positional synchronization of the plate cylinder 2 during rolling, and the rotation of the plate cylinder as the sector BA (hereinafter referred to as the "variable speed sector") rolls past the printing nip. The speed can be increased or decreased and precise positional registration is restored at the ends of the variable speed sector so that the auxiliary panels can be accurately printed onto the packaging material.

FIG. 3 illustrates the possibility of varying the repetition length to achieve the desired result. Curve 31 shows the shortest repeat delay length, curve 32 shows a somewhat longer repeat length, and curve 33 shows the shortest repeat delay length.
shows an even longer repeat length, and curve 34 represents the third
The longest length of the four repetition lengths depicted in the figure is shown. The vertical axis represents the surface speed of the printing press and the horizontal axis represents the angular position of the plate cylinder.

The rolling of the sector at various constant speeds past the printing nip is represented by the distance X on the horizontal axis, and the rolling of the sector at various variable speeds is represented by the distance Y on the horizontal axis. As can be seen, the time period of each interval It varies depending on when. Expect the material being printed to be a continuous web17
and it spans a sector of constant speed printing plate 3a, 3
Taking into account that it moves with a speed v1 equal to the surface speed of b, the repetition length of the material is e.g. The 'ri' varies according to the particular envelope chosen for the sector of variable speed.

In a conventional printing press, such a change in the repeat length and perhaps also the aforementioned change in the spacing between each image of the main panel and the next successive image of the auxiliary panel eliminates one plate cylinder and creates a different In contrast to this, it is necessary to replace the plate cylinder with another plate cylinder having a different diameter, thus making it possible to change the repetition length even though the plate cylinder operates at a constant speed. The printing machine described with reference to FIG.
(with a disadvantage of several tens of minutes), and allows the repeat length to be changed by the first activation of the switch.

Also, instead of the two plates or plate areas 3a, 3b,
There is a continuous version over [sectors of constant velocity],
Any of the equipment illustrated in FIG. 2 may be useful when changing the repeat length between an image printed by the plate and the next image printed by the plate.

As can be seen from the above description, although the printing press according to the invention offers advantages in particular with respect to the printing of packaging materials, it is nevertheless suitable for printing pastes in monochrome or multicolor printing presses for other applications. A facility for changing alignment electronically offers a significant improvement over conventional direct conduction systems, which provide very limited printing opportunities.

Particularly useful possibilities of the printing press according to the invention are as follows. In other words, conventionally, in order to change the repetition length,
Many different plate cylinders of different diameters can be used in one set,
In contrast, the printing press according to the invention (equipped with variable speed sector J) does not require changing of the plate cylinders, and the speed A single river large diameter plate cylinder (1/ In fact, the so-called "foil r-plate carrier" system of plate mounting allows plates of any size to be supplied precisely to the circumference of the plate cylinder. (attached to a sheet of carrier foil, this foil can then be easily attached to the plate cylinder and the flexographic plate is mounted on cylinder 1) for the "de-inking" movement of the plate cylinder or the "printing" movement of the ink roller. ” Interlocking would be unnecessary. In this way, a very simple printing press with fixed sleeve plate cylinders and ink rollers is possible. The carrier foil for the form cylinder ensures precise positioning of the form with respect to a lateral reference axis or baseline of the form cylinder by using some clamping or pinning system.

In the description of
9 has been described as a Nutepper motor, it is of course possible to use any type of servo motor in place of the Stepper motor.

Instead of directly coupling the ink roller motor 11 to the first plate cylinder motor 9 as described above, according to another modification, the ink roller motor 11 is controlled responsively to the main drive motor 6 with a sufficiently high precision. and is responsively controlled to the main drive motor 6 of the pressure cylinder 1 to maintain pure roll contact between the printing form cylinder 2 and the ink roller 4.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of the inking unit and plate cylinder assembly of a multicolor printing press, the pressure cylinders of which are also shown, and which is in accordance with the invention. FIG. 2 is a side view showing details of the printing cylinder and adjacent plate cylinder and illustrating another embodiment of the invention. FIG. 3 is a plot of the circumferential velocity of the printing plate versus each velocity of the eye, and is applicable to the embodiment of FIG. 2. 1 Pressure cylinder 2nd plate cylinder 3rd plate 3a 1st plate area 3b Auxiliary plate or plate area 4 4 Engi roller, anilox ink roller 5 Main shaft 5a Rotating shaft 6 Electric drive motor 7 Tooth I/I pulley 8 Toothed belt 9 Digitally controlled electric motor 10 Drive shaft 11 Digitally controlled electric motor 12 Drive shaft 13 Open mechanical joint 14 Soaking carrier 15 @screw 16 Stepper Φ motor I7 Stepper Φ motor 18 Lead screw 19 Stepper Φ motor 20 Control device 21 Control connections 22 Proximity detection system, proximity sensor 23 Proximity detection system, proximity sensor 24 Machine frame 31 Curve 32 Curve 33 Curve 34 Curve Vl Speed X Interval Y 1ift interval

Claims (1)

Claims: l. A forme cylinder, a rotary support for the material to be printed, a first motor for driving said forme cylinder, and a second motor for driving said support for the material to be printed. Precisely controlling the relative rotational position of the motor and the first and second motors to achieve the rotation of the motor with respect to the rotary support without the need for a mechanical interconnection between the plate cylinder and the support. A rotary printing press characterized in that it comprises a control means for ensuring synchronization of the position of the plates on the plate cylinder; 2. The rotating support is a pressure cylinder, and the plate cylinder is arranged to form a printing nip between a plate thereon and a medium passing over the pressure cylinder. The rotary printing machine according to item 1. 3. further comprising an ink roller, said ink roller being arranged in rolling contact with the plate on said plate cylinder and driven by a third motor; The rotary printing press according to claim 2, which is effective for maintaining rolling contact between the ink roller and the plate cylinder by controlling the position of the ink roller. 4. The plate cylinder or the plate. 4. A method according to claim 1, further comprising means for moving each of the cylinders into a printing position with respect to the rotary support, the means for moving said plate cylinders being controlled by said control means. 5. A rotary printing press comprising means for moving said ink roller into contact with a plate on said plate cylinder, said means for moving said ink roller being under the control of said controller. 6. The rotary printing press is a multicolor printing press and includes at least two plate cylinders, each of said plate cylinders, cylinders supports plates for printing different colors from the plates of said plate cylinder or each other said plate cylinder, each said plate cylinder having its own first motor, and said control means controlling said plate cylinder. as claimed in claim 2.3 or 5; A rotary printing press as claimed in claim 4 when dependent on claim 2 or 3. 7. A rotary support for the material to be printed and its for rolling contact in the image transfer nip. a plate cylinder capable of supporting a plate over a portion of the cylinder surface; a first motor for driving said plate cylinder; and said rotational support; a second motor for driving said plate cylinder; and a position of said plate cylinder with respect to said rotational support. control means for maintaining the positional relationship at a constant surface velocity of the plate cylinder over a first sector of rotation of the plate cylinder;
111 The speed of the plate cylinder is increased over a second sector of rotation of the plate cylinder in order to change the time delay between the end of the sector and the start of the first sector in the next successive rotation of the plate cylinder. A rotary printing press characterized in that it is effective for changing. 8. Claim 7, wherein there is a plurality of said plate cylinders and said control device is effective for varying the position and rotational speed of each of said plate cylinders with respect to the movement of the common said rotating support. The multicolor rotary printing machine described in Section 1. 9. A multicolor rotary printing press according to claim 8, wherein the rotary support is a pressure cylinder and each of the plate cylinders is characterized by a respective printing nip with the pressure cylinder. 10. A rotary printing press substantially as hereinbefore described with reference to and illustrated in FIG. 1 of the accompanying drawings. 11. A rotary printing press according to claim 10, modified substantially as hereinafter described with reference to FIGS. 2 and 3 of the accompanying drawings. 12. A plastic packaging material printed by the printing machine according to any one of claims 1 to 11. 13. A web of plastic packaging material printed using a rotary printing press according to any of claims t-12.