DE3007801A1 - Synchronising image transfer cylinders - uses sensors detecting peripheral markings to produce signals controlling rotational speeds - Google Patents

Abstract

The image transfer system comprises a number of transfer cylinders (1-3) which are to be driven synchronously. Each cylinder carries markings (10-12) around its periphery which are detected by a sensor (13-15) which produces signals in response to the passing markings. The signals represent the angular position of that cylinder relative to a reference and are fed into a control circuit (16) which adjusts (7-9) the drive (4-6) of one or more cylinders so as to correct any deviation from their desired relative angular posn. The markings may have binary characteristics and may be arranged in axially adjacent peripheral series, each acting on its own detector, so that, at any moment, a number of simultaneous signals is produced by each sensor which together represent a multi-bit code.

Description

Printing machine assembly, cylinder therefor and method too

its manufacture.

The invention relates to the control for congruence on a Printing machine arrangement with a number of transfer cylinders or transfer rollers, which should be driven synchronously.

In a printing press with several transfer cylinders for partial images or image extracts are provided which are successively transferred or applied UTn then together to produce the overall picture, which is a black-and-white picture or a color image, the difficulty of maintaining arises the correct position of the imprint with respect to the partial images relative to one another. Not only the respective angular speeds of the transfer cylinders or rollers, but also the respective instantaneous relative angular position must be precisely determined will. Ps mechanical control systems are known in which changes in the instantaneous relative angular position of the individual transfer cylinders a constant visual inspection of the final print image for deviations be monitored. However, these systems have the disadvantage that the reaction to Deviations very much is slow and that when there is a deviation occurs, relatively large amounts of the printed matter are lost before a correct setting of the corresponding angular position of the transfer cylinder or forme cylinder is restored.

There are also automatic control systems or regulation systems for synchronization the operation of a number of printing units with multiple rollers has been developed. For example, Rls Patent 3,896,377 gives a method for measuring the relative angular positions of two cylinders, at which a counter the passage counts consecutive black and white lines of a grid or grid, which is arranged on the circumference of one of the cylinders, the leading edge of a white mark on one cylinder shows the flow of pulses to the counter for the counting grid of the second cylinder is free.

British Patent 1,434,875 shows a number of devices for scanning a pattern or an arrangement of marks on the circumference of a cylinder, for example photoelectrically. The ones given in the cited publications Methods use a count to indicate the relative position between several rotating cylinders.

Furthermore, US Pat. No. 3,675,098 shows a digital control system, in each of which digital signals an instantaneous angular position or phase position of the various printing units in one machine and each digital signal is differentially compared with a digital reference signal which is a reference phase setting reproduces. The printing press control device never contains a pulse generator, expediently a conventional binary-coded decimal walker disc, which with the drive speed of the printing press is driven by, for example is directly coupled to the main drive shaft of the printing machine, so that one receives a digital signal which corresponds to the actual value of the phase adjustment or Corresponds to the angular position of the printing press. This arrangement has the disadvantage that no devices for scanning marks or indicators on the circumference of the cylinder oler <1er roller of the printing unit are provided, so that not the same accuracy is achievable, which in itself by measuring the relative positions of the image-transmitting Circumferential surfaces themselves would be achievable.

The invention is intended to solve the problem in a printing machine arrangement the relative angular positions of the individual transfer cylinders or forme cylinders with high precision with a comparatively simple design of the detector circuits to be able to adjust.

This object is achieved according to the invention by the in the characterizing part of the appended claim 1 specified features solved.

Fs are al-so characteristic display means or marks along the tJmfanges the transfer cylinder or forme cylinder arranged, which the respective Identify the angular positions of the cylinders or rollers. The brands are involved a detector, which detects the passage of the marks as the rollers rotate or cylinder responds and generates a signal that has the shape of a multi-digit Code word has that of the relevant angular position of the cylinder or the roller is equivalent to. The signals can be sent to a control circuit to correct the deviation the relative angular positions of the individual cylinders or rollers are supplied, where an adjustment is made to the drive of one or more of the cylinders or rollers will.

Suitable means of display or marks can be sections of the perimeter area which have characteristic properties that belong to one or the other assume two states, with the marks in rows on the circumference at an axial distance are provided side by side. Each of the series can be linked to a separate Detector or scanning means cooperate based on the respective property of the responding under it passing surface, so that the respective instantaneous Scanning result with respect to the rows to a characteristic grouping at the same time occurring scanning pulses of the detectors of the detector arrangement leads. never pulse grouping In its entirety, forms a multi-digit code word for the precise determination of the angular position of the cylinder or the roller.

The various multi-digit code words which are used by the detector arrangement of the individual rollers or cylinders are delivered, preferably arrive at one Comparator, in which relative angular positions by comparing the multi-digit words to be established. The comparator can then send one or more correction signals generate, for example, an instantaneous angular position of a roller or of one cylinder is used as the reference signal, while the drives of the others Rolls or cylinders are adjusted according to size and direction to such an extent that that deviations are corrected.

According to another embodiment, the multi-digit digital words from the detector devices assigned to the individual rollers or cylinders the comparator led, which also multi-digit digital words from an independent Signal generator are supplied. The comparator then supplies control signals as a function of deviations between the digital words indicating the respective actual positions ind the reference word to correct the drive of the individual cylinders as necessary.

r; em According to another embodiment, which is again designed differently, a thin-walled transfer cylinder or forme cylinder in a printing machine or a printing unit of the type described above are used and carries his around tTmfanqes series of surface areas that are characteristic in the axial direction template different light reflection, which with an electro-optical scanning device cooperate.

It is also possible to create characteristics that are characterized by different surface areas Generate patterns of electrical charge, these charge marks with a cooperate electrostatic scanning device.

There is also the possibility of surface areas of the cylinder or whale characteristic groups of markings influencing a magnetic field to form, which cooperate with a magnetic scanning device. Deepened Areas of the roller or cylinder surface which are below the magnetic scanning device run through, a change in the magnetic field which can be used for the formation of signals Bring about the field of the scanning device. A channel or a roller that can be used for this purpose a cylinder can have a pattern of electrically insulating surface areas on it a cylindrical support, the insulating surface areas correspond to the recessed surface areas made on the cylinder surface should be. Then the carrier is electrolytically coated with a metal coating provided to form the finished cylinder.

In addition, it should be noted with regard to advantageous refinements and further developments the printing machine assembly referred to the appending claims, their content is hereby expressly made part of the description without being affected by it Ask to repeat the wording.

Exemplary embodiments are described below with reference to the drawing explained. The figures show: FIG. 1 a schematic illustration of a printing machine arrangement, Fig. 2 a schematic perspective view of a forme cylinder or a roller, which is provided with three rows of marks interacting with scanners, Fiq. Figure 3 is a development of a surface portion of a five-row roller of brands, Fig. 4 is a schematic representation of an atis section of the cylinder or roller surface in cooperation with an electro-optical scanner, Fig. 5 is a schematic illustration of a part of a roller or a cylinder with Surface areas that interact with an electrostatic scanner, Fig. 6 is a schematic illustration of a roller with patterns of surface areas; cooperating with a magnetic scanner, Fiq. 7 is a schematic illustration another embodiment of an electro-optical scanner and FIG. 8A schematically Illustrations to explain up to 8D of the various steps involved in creating the project a marked cylinder.

Figure 1 shows a schematic representation of three transfer cylinders or forme cylinders 1, 2 and 3, which are, for example, conventional screen printing cylinders or transfer cylinders such as those used in electrostatic printing will. Each of these cylinders is set in rotation by means of a drive, where the drives are marked with 4, 5 and 6. Each of the drives has at least a rod input 7 or 8 or 9, which is used to control the speed of the relevant Drive for the cylinder can be acted upon.

Characteristic markings are denoted by n, 11 and 1 and arranged along the circumference of each of the cylinders, w <> - up further down in the individual will be received. markers never work with detector devices 13 or 14 or 15 together. Detector devices never consist of several individual scanners or detectors, their OUT-outputs with a central signal processing unit 16 are connected. In the embodiment of Figure 1, the output provides one Reference detector 17 reference signals, which are generated, for example, by marks 18, which are provided on a Bezuqswalze 19, which by a drive 20 with constant Speed is applied.

The detector devices connected to the central signal processing unit 16 13, 14 and 15 monitor the respective instantaneous angular positions of the cylinders 1 or 2 or 3 and make it possible to derive the speed of the relevant cylinder. By comparing the signals representing the angular position with respect to the cylinder 1 it is immediately possible to determine whether the current angular positions the cylinders 2 and 3 coincide with the angular position of the cylinder 1 or whether one or both of cylinders 2 and 3 is leading or lagging cylinder 1. If the latter is the case and there is no synchronism, the central Signal processing unit 16 a correction & ignal provided, which to the control inputs 8 and 9 of the cylinders 2 and 3, so that the speed cylinders 2 and 3 are increased or decreased, whereby the correction lasts as long as until the current angular position of the cylinder is set so that a There is synchronism with cylinder 1.

Deviating from an arrangement in which a cylinder is used as a reference is used, according to another embodiment, a train signal generator are used, which Stel.lungssignale generated that formed accordingly are like that Position signals, which from the detector devices 13, 14 and 15 are offered, whereby the drives 4, 5 and 6, which the cylinders 1, 2 and 3 are assigned to be controlled so that the current angular positions the cylinder correspond to the reference signal value, which is a synchronization angular position represents. For example, it can be used as a reference signal generator or synchronizing signal generator a fin device with a reference mark drum 19 can be provided on the pattern of marks 18 are provided and which of a drive 20 with constant speed is driven. The reference marks are scanned by the scanning device 17, which presents signals at its output, which also. the signal processing unit 16 are fed. The latter supplies the inputs 7, 8 and 9 of the drives 4 or 5 or 6 such control signals that the angular positions of the cylinders or rollers 1, 2 and 3 always match the angular position of the drum L9.

Figure 2 shows schematically one of the cylinders, for example the cylinder 1, which carries a circumferential marking 10, which in the present case consists of three all around extending rows 10a, 10b and 10c consists, the three rows in axial Are arranged spaced apart. Brands never have the shape of strings lighter and darker areas with a certain minimum length, which is shown in Figure 1 with r. is called. Each of the three rows 10a, 10b and 10c is separated by q one of three light-sensitive detectors scanned in the actuator device 13 are summarized by the block symbols 13a, 131) and 13c are symbolized. Each angular position 0 of the cylinder relative to the zii the vertical line X-X given reference position is characterized by a characteristic Combination of three white or black marks 21a, 21b and 21c marked. It goes without saying that in FIG. 2 the dimensions of the marks or marking areas are exaggerated relative to the dimensions of the cylinder. In practice it is possible Make markings that are 50 microns in the circumferential direction, for example measure up, so that in the case of a cylinder with a total circumferential length of, for example 1000 mm an accuracy or resolution of 360. 60 50/6 @@ minute / 50 um mark results. Each search for a specific angular position causes the detector device 13 for generating an output signal which has the form of a digital code word has, in which, for example, the dark areas are represented by the binary value 1 and the light areas are represented by the binary value 0. With a corresponding Number of rows corresponding to output signals of the detector device 13 with a sufficient number of digits it is possible to achieve a very high accuracy or To achieve resolution. For example, for the C, accuracy just mentioned from one minute to the clear identification of the rotary positions over a full one Fourteen digits of the signal are necessary for one revolution, corresponding to fourteen rows.

FIG. 3 shows an example of the so-called Gray code with five rows of marks 23 to 26. If a dark marking area has the digital value 0 and a lighter Marking area identifies the digital value 1, then the place which is indicated by the arrow 27 is identified by the code 11110, the position accordingly the arrow 28 through the code 11100 and the position corresponding to the arrow 29 through signaled the code lllNl. The so-called Gray code has the rigidity that when transition from one code word to the next only changed one binary digit so that no indefinable intermediate values can occur. The usage such a code for the coding of angular positions is known per se. With code words that have only five digits, usually none Achieve sufficient accuracy, since for a desired accuracy, as si As mentioned above, fourteen digits are necessary. Dic sampling is for example carried out along the line 31, the detector device 3n in the present Cases contains five scanners or individual detectors.

Figures 4, 5 and 6 show various modified embodiments for markings and associated scanning systems.

In Figure 4, a cylinder wall 33 is shown on which marks in Shape of patterns of certain paint particles 34 are attached, such as by means of a certain photo-etching technique can be generated. The scanner or detector uses two light guides 35 and 36, each about 50 in diameter Have microns. At the end of the light guide 35 there is a light source and at the end of the light guide 36, an electro-optical element is attached, which generates an electrical pulse when light hits the element. Is located If there is no marking 34 in the area of the beam path, the incident light beam will be 37 is reflected from the surface of the cylinder 33 and emerges as a reflected light beam 88 into the light guide 36 in order to reach the electro-optical element and there to generate an output pulse that is a binary I, for example. Is a If paint marking is present, the incident light beam 37 is partially absorbed and partially reflected. The reflected light beam 38 then has considerable lower intensity, so that no output pulse is excited, which is a binary one 0 corresponds.

Figure 5 shows an embodiment in which the markings as a pattern of electrically insulating particles 40 are applied, which are on the surface of the cylinder 41 are located. The insulating particles or paint particles 40, which migrate together with the surface of the cylinder 41 in the direction of arrow 42, are electrostatically charged by means of a corona generator 43, the metallic Surface of the cylinder 41 does not accept any charge, so that an electrostatic scanner or detector 44 can make a distinction. The output impulses which correspond approximately to a binary 1 or a binary 0, are presented at the output 45 and each deliver one digit of a multi-digit Code words, which reproduces the respective angular position of the cylinder 41.

In Figure 6, a scanning system is shown in which the markings in the form of a pattern of recesses 50 are attached, which in the surface of the cylinder 5 are either present or absent. A magnetic scanner r,? responds to these markings. Each scanner consists of a thin rod 53 made of ferromagnetic material, the rod being surrounded by a winding 54 which is connected to an oscillator 55. The passage of a recess 50 under the rod 53 results in a change in the magnetic field distribution, which can be detected by the oscillator 55 so that at an output terminal 56 a pulse appears, which represents either a binary 1 or a binary 0.

In the described embodiments, each marking line is made scanned by a separate scanner. never from the scanners or detectors formed detector devices each deliver groups of sampling pulses, which overall represent the distinguishing signal that has the shape of a multi-digit Word corresponding to a very specific angular position of the cylinder.

Figure 7 shows an electro-optic scanner or detector which can be used in connection with a cylinder 51 ', in the surface of which the markings are provided as a pattern of recesses 50 '. In the present case, made by a light source 57 Gehrauch, the radiation of which by means of an optical Systems 58 and 61 through a semi-transparent mirror 60 onto the cylinder 51 'projects or focuses wirtl. Part 59 'of the radiation bundle (approx half of the radiation of the radiation beam 59) winl from the mirror 60 in the direction deflected to the left, while the meil bundle 59 '' that is allowed through, a picture on the Surface of the cylinder 51 'forms. Ain't no If there is a recess, then a part of the reflected reed becomes part of the semitransparent one Mirror 60 again as a radiation bundle 59 '' '(shown in dashed lines in FIG. 7) reflected and projected onto a photodiode 63 by an optical system 62, which is operated in its saturation state and generates a diode current, which depends on the size of the irradiated surface.

The generation of an output signal as a function of the diode current takes place in the signal processing unit 64 indicated schematically. Is a There is a recess 5n 'below the lens 61, a larger surface area becomes irradiated, as indicated at 65 and this results in a larger surface area a projected beam 66 emerging from the semi-transparent mirror 6Q is reflected as a radiation beam 67 and to a larger light spot on the Photodiode 62 leads. This causes a correspondingly larger diode current. It results There is thus a clear distinction between the presence and the absence of Recesses in the wall of the cylinder 51 '.

FIGS. 8A to 8D illustrate a preferred embodiment the production of a thin-walled cylinder, which with a pattern of recesses is provided in connection with detector devices in the Atisführungformen according to Figures 6 and 7 are effective in the manner indicated or with certain Layers, for example lacquer layers, can be filled and then with detector devices cooperate, as shown in Figures 4 or 5. For example, can the surface of a copper carrier body 70 with rows of insulating spots or Islands 71 according to the pattern of the recesses in the wall of the thin-walled Cylinder are provided. Then the cylinder body, such as using Nickel, deposited electrolytically on the support body in an ithlicher way. First As shown in Figure 8B, there will be no material 72 on the insulating islands 71 deposit yourself. However, if the deposition continues, so grow the areas above the insulating islands 71 gradually close and a cylinder is formed 73 with surface recesses 74 on the carrier body 70. Finally, FIG. AD shows a cross-section through the cylinder wall 75 of one according to that given here Process manufactured cylinder. islands 71 are extraordinarily thin and the never Recesses 7 ', which arise on the back of the cylinder, are therefore extraordinary flat.

Claims (12)

Claims 1. Printing machine arrangement with a number synchronously Transfer cylinder to be matched, characterized in that at least one the transfer cylinder (1, 2, 3) has a large number of clear markings (10a, lOb, lOc), which around the cylinder circumference and at a distance from each other are arranged so that each of the markings has a different angular position of the cylinder in question identified and that one or more detector devices (13, 14, 15) are provided which examine or examine the markings and each generate or generate a signal that has the shape of a unique, multi-digit code word corresponding to the respective different angular position of the cylinder in question. 2. Arrangement according to claim 1, characterized by a control unit (16) for the automatic adjustment of the drive (4, 5, 6) of one or more of the named cylinder (1, 2, 3) as a function of the output signals of the detector device or the detector devices (13, 14, 15). 3. Arrangement according to claim 2, characterized in that at least two transmission cylinders are each provided with the markings and that the Control unit (16) contains a comparison device, which the signals accordingly receives the multi-digit code words and a comparison of the signals generated by the signals Again, any angular positions of the associated cylinders are made, depending on one or more correction signals for setting the drive from the comparison one or more of the cylinders depending on deviations from the current one relative angular positions of these cylinders to restore their synchronism is generated or will. 4. Arrangement according to claim 3, characterized by an unair-dependent Reference signal source (17, 18, 19, 20) which is sent to the comparison device of the control unit (16) supplies multi-digit reference word signals which correspond to the multi-digit reference word signals are compared, the detector devices assigned to the individual 7th cylinders (13, 14, 15) are presented, the correction signal or the correction signals depending on deviations between the detector signals and the signals the reference signal source is generated. 5. Arrangement according to one of claims 1 to 4, characterized in that that the markings are formed on cylinder flat cuts, which with respect to of a characteristic figure have two different states, wherein the markings in a plurality of rows extending around the IT perimeter and are arranged at an axial distance next to each other and each row with a separate one Scanner or detector cooperates on the characteristic in question Property responds in such a way that the detectors together the d (Tn pertaining Form cylinder associated detector device and in a certain scanning moment as a result of the scanning of the rows of marks, a group of scanning pulses present which represents the output signal of the detector device. 6. Arrangement according to claim 5, characterized in that the cylinder surface sections Include about fourteen rows of marks, so that code words with fourteen digits result, which indicate the respective angular position of the cylinder in question. 7. Arrangement according to claim 5 or 6, characterized in that the Surface sections which are axially spaced apart over the Rows of marks along a characteristic pattern stronger and less smelly Form light-conducting areas, which with an electro-optical scanning device cooperate (Figure 4 ß. Arrangement according to claim 5 or 6, characterized in that the surface sections, which are axially adjacent to one another, across the rows of marks a characteristic Patterns relating to an electrical charge distribution D work that with an electrostatic Scanning device interacts (Figure 5). 9. Arrangement according to claim 5 or 6, characterized in that the Surface sections which are axially adjacent to one another over the rows of marks a characteristic pattern of influencing the magnetic field distribution form structures which cooperate with a magnetic scanning device (Figure 6). 10. Cylinder for a printing machine arrangement, in particular according to one of claims 1 to 9, characterized in that extending around len cylinder circumference a plurality of single markings are provided at a distance from one another in this way are, d each marking indicates a certain angular position of the cylinder, the markings as a pattern of recessed and non-recessed surface areas the cylinder surface are formed. 11. Cylinder according to claim 10, characterized in that the recess areas are tlaß in a plurality of rows of marks extending around the circumference of the cylinder are arranged, with the individual0 rows of marks lying next to one another at an axial distance. 12. A method for producing a cylinder according to claim lfl or 11, characterized in that a cylinder support body with patterns electrically insulating surface areas is provided, which with the on the cylinder surface align to hildenden recessed areas and that then to education the Cylinder wall metal is deposited electrolytically, which is in the area of the insulating Areas formed wells (Figures 8A to 8D).