DE202008004285U1 - imaging - Google Patents

Abstract

An imaging device for imaging a printing form (12) positioned on a cylinder (11), comprising at least one imagesetter (13) and at least one imagesetter controller (21), the or each imagesetter (13) having a plurality of emitters (34), the exposure radiation for exposure the printing form (12) emit, and wherein the or each exposer (13) when moving relative to the printing plate to be exposed (12) linearly and the printing plate to be exposed (12) relative to the or each imagesetter (13) is rotatably movable thereby characterized in that:
a) the or each exposure controller (21) reads image data (23) from an image data device (22) which processes read image data (23) in a data restructuring unit (28) and provides resulting image data (29) to the respective imagesetter (13) for further processing;
b) the respective imagesetter (13) writes the resulting image data (29) into at least one intermediate memory (31), wherein output data of the or each temporary memory (31) after passing through a delay unit (32) and a pulse duration shaping unit (33) as drive signals for the emitter (34) of the respective imagesetter ...

Description

The The invention relates to an imaging device having at least one Imagesetter, in particular details of the control of the or each imagesetter in the manufacture of a printing form, wherein during the Bebierungsvorgangs a projection plane of exposure beams the or each imagesetter and a printing plate surface a relative movement to each other.

to Imaging of printing forms typically becomes imaging devices used with multi-channel imagesetters, which are laser light sources, in particular diode laser arrays or via fiber optic cables merged single laser, may have. Exposure beams emitted by the light sources of the respective imagesetter are typically provided with imaging optics for beam shaping and beam steering projected onto the printing plate surface, to image elements on the printing form by direct action on a Layer of the printing plate or by acting on a transfer layer to create. Depending on the intended printing process, the thus produced Image elements ink-accepting or color-repellent in the printing process.

In In an imagesetter, the light sources are typically linear arranged, the emitted exposure beams occur in one so-called emitter level and hit the printing form in one so-called projection level. This is the baying order the light channels on the imaging optics on the printing plate surface Scales projected. Typical imagesetters bring together with the imaging optics during the imaging process a relative movement between the printing plate and the projection plane the light sources through, leaving the entire area to be imaged is covered by the projections of the light sources.

A preferred embodiment of such an imaging device has a cylinder with high concentricity, on the a plate-shaped or sleeve-shaped Pressure form can be clamped or pushed. In the course of the Bebierungsvorgangs is along the cylinder surface a multiple light sources comprehensive exposure performed, so that its light beam projections during the exposure traversing in the tolerance range of the depth of focus to the printing plate surface run. In addition, the cylinder is in rotation with a constant as possible peripheral speed offset so that the picture elements in the form of a helix on the printing plate surface be set.

to Avoiding image errors requires that the imaging line the light channels on the printing surface during of such an imaging process the ideal course of a straight line approximated by appropriate measures. These For example, parallel to the axis of the Bebilderungszylinders run. Due to the manufacturing process, the light sources of the imagesetter can be used hard to line up with sufficient accuracy in an ideal line, so that the precision required for a picture reproduction achieved at the issuer level. Centers of adjacent emitter beams are often offset from each other and do not run on an ideal line. For multi-channel diode lasers, so-called Diode laser arrays, this property is also known as the smile effect.

DE 10124215A1 describes a Bebilderungseinrichtung with a drive device for the time delay of the triggering of adjacent adjacent light channels. The surface speed of the printing plate is essentially assumed to be constant.

Of these, The present invention is based on the object, a novel imaging device with at least one imagesetter to accomplish. This task is performed by an imaging device solved according to claim 1.

With The present invention, it is possible an individual On delay and on pulse duration adjacent Light channels for imaging their points of light on the printing form to provide in an ideal line. The surface speed the printing form can vary and the delay device the light channel control can with a speed independent Parameter set to be operated. In relation to the image resolution can the large geometric distances of the Points of light in the image plane orthogonal to the ideal imaging line be compensated. The density of the image points in combination with a tipping of the imagesetter line can be increased. The execution of data processing for the The imaging process used can be directly in the imagesetter control respectively.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below. An embodiment of the invention will be apparent to, but is not limited to explained in detail the drawing. Showing:

1 : a schematic representation of an imaging device according to the invention together with a cylinder to be imaged printing form receiving cylinder;

2 : a detail of the imaging device of the 1 ;

3 : another detail of the imaging device of the 1 ;

4 : another detail of the imaging device of the 1 ;

5 : an alternative to the detail of 4 ;

6 : another alternative to the detail of 4 ; and

7 : A schematic representation of an alternative imaging device according to the invention together with a cylinder to be imaged printing form receiving.

1 shows a highly schematic representation of an embodiment of an inventive imaging device 10 together with a cylinder 11 on which a printing plate to be imaged 12 is positioned. The imaging device 10 of the 1 includes a multi-channel imagesetter 13 with emitters or light sources not shown in detail.

According to 1 have the emitters or the light sources of the imagesetter 13 and thus the individual imaging channels of the same in a so-called emitter level 14 of the imagesetter 13 different degrees to each other or to an ideal emitter line 20 offset light exit positions 15 on. The light rays emitted by the emitters or light sources are transmitted via imaging optics 16 on the imaging level or projection level 17 the printing form 12 projected. In this projection plane 17 have adjacent points of light 18 orthogonal to a desired imaging line 19 Distances that can exceed the distance between two consecutive pixel rows. In doing so, the imaging line must 19 on the printing surface not parallel to the axis of the cylinder 11 run, but may also be arranged at an angle to her.

In the embodiment of 1 is an imagesetter control 21 from the imagesetter 13 separated and formed as a functionally separate unit. The imagesetter control 21 prepares from an image data device, preferably designed as an image data memory 22 received image data 23 , which may be optionally packed, for the imaging process so that the resulting data arrangement on the electronic processing in the imagesetter 13 and the nature of the imaging process is tuned. For this it is advantageous, but not mandatory, that image data 23 for a complete imaging cycle for exposure control prior to the exposure process.

The imagesetter control 21 receives the image data 23 from the image data memory 22 via an interface 24 and controls the imagesetter 13 via an interface 25 at.

For temporary storage of image data 23 is the imagesetter control 21 with at least one storage medium, in particular according to 2 with two storage media 26 and 27 , equipped. A data restructuring necessary for an exposure process takes place in the imagesetter 13 associated exposure control 21 about a data restructuring process in a data restructuring unit 28 ,

In the imaging device 10 of the 1 the imagesetter passes over 13 During the exposure process, the printing plate surface with a linear movement with the relative velocity v and requires due to the rotational movement of the cylinder at the speed n when imaging the reproduction of the image data in the form of a multi-track wide helix. For an output of the image data in this format form the so-called tilting and the so-called distortion of the image data 23 the necessary preparatory data restructuring operations in the data restructuring unit 28 the imagesetter control 21 ,

In this data restructuring process, in one variant, the optionally compressed image data are retrieved from the storage medium 26 into which the data has been loaded in a preparatory step, read out in blocks or in one piece, decompressed and by means of the data restructuring unit 28 the imagesetter control 21 restructured. These data adapted to the imaging process can then either according to the data path a) of 2 directly from the storage medium 26 to the imagesetter 13 be transferred, or there is a new buffering, either according to the data path b) in the separate storage medium 27 or according to the data path c) in the original storage medium 26 , From the storage media 26 . 27 The restructured image data may then later be relocated to the imagesetter at the time of the restructuring process 13 be transmitted. To reduce the data volume and transmission rates, the restructured image data may be compressed prior to each storage or transmission.

In general, the picture elements created in an imaging cycle can be printed on the printing form 12 include only parts, extracts or sections of the entire printed image. Here, either the respective image extracts are completely on the imagesetter control 21 or only image data excerpts of the exposure controller are loaded 21 transmitted data to the imagesetter 13 forwarded to image reproduction.

In general, the image data transmission can always be used for exposure control 21 upstream of the exposure process or temporally parallel to this process. In image data transmission, data compression methods can be used.

Table 1 below shows the image data color separation of a simple rectangular figure with 1-bit color depth. The gridded rectangle figure is highlighted in gray. Row column 1 2 3 4 5 6 7 8th 9 10 1 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 3 0 0 1 1 1 1 1 1 0 0 4 0 0 1 0 0 0 0 1 0 0 5 0 0 1 0 0 0 0 1 0 0 6 0 0 1 0 0 0 0 1 0 0 7 0 0 1 0 0 0 0 1 0 0 8th 0 0 1 1 1 1 1 1 0 0 9 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 Table 1

A Direction of movement of the light channel array relative to the printing plate surface runs from top to bottom in Table 1 Direction of lines 1 to 10.

Table 2 below illustrates that in the data restructuring unit 28 restructured image data after rendering it for output in the form of a helix during the imaging process. The limited resolution of this exemplary data set allows a stepped distortion of the rectangle figure to be displayed. Row column 1 2 3 4 5 6 7 8th 9 10 1 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 3 0 0 1 1 1 1 1 1 0 0 4 0 0 1 0 0 0 0 1 0 0 5 0 1 0 0 0 0 1 0 0 0 6 0 1 0 0 0 0 1 0 0 0 7 1 0 0 0 0 1 0 0 0 0 8th 1 1 1 1 1 1 0 0 0 9 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 Table 2

The image data restructuring outlined above can be extended to z. To compensate for image rendering errors, particularly cushions. or keystone distortion or so-called fan-out effects. additionally can be so-called spreads or scaling of the printed image form further process steps of image data restructuring. Farther is the arrangement Verzaden compensated.

This processed image data 29 are optionally compressed via the interface 25 and a data link with a high transfer rate to the imagesetter 13 transfer.

The imagesetter 13 the exposure device 10 optionally decompressed in one unit 30 this data stream from processed image data 29 and preferably combines it into FIFO-wide data words, these data words being embodied in at least one intermediate memory preferably designed as FIFO memory 31 to be written. The output data of this buffer 31 be after passing a delay unit 32 and a pulse duration shaping unit 33 as drive signals to the individual (1 to N) light sources or emitters 34 and thus the N light channels of the imagesetter 13 forwarded.

The readout clock for the or each cache 31 , hereafter called pixel clock, is an interpolated encoder signal 35 of the cylinder 11 won. The interpolation of the original encoder signal 36 takes place in an encoder interpolation unit 37 and matches the resolution of the encoder 38 to the desired resolution of the print image.

Typically, this will be the effective encoder signal frequency with the factor X in the encoder interpolation unit 37 to the pixel signal frequency 35 multiplied. Among the effective encoder pulses is in this context, for. B. understood the superposition of the signal edges of two offset encoder signals of the two lanes of a typical encoder. For the factor X: X = (A / 25.4 mm / in) · (U / I EFF ) where A is the desired image resolution in dpi, where U is the circumference of the cylinder 11 in mm and where I _EFF effective encoder pulses per revolution of the cylinder 11 are.

Phase-locked loop (PLL), delay-locked loop (DLL) circuitry, or the direct digital synthesis (DDS) method in the encoder interpolation unit is used for phase-constant frequency multiplication between the encoder signal and the pixel signal 37 used.

As already mentioned, this pixel clock signal becomes a read-out clock for the or each buffer 31 used. Another encoder interpolation unit 44 in turn multiplies again this pixel clock with the methods known from the encoder interpolation (PLL, DLL circuit or DDS) to a higher frequency clock, hereinafter Feintakt 39 called.

By using these interpolation methods, the higher frequency fine clock has 39 a fixed phase coupling to the pixel clock 35 so that channel-specific switch-on delays and pulse durations of a very high resolution can be realized with its help. The frequency ratio K of thus generated fine clock 39 at pixel rate 35 is independent of the surface speed of the forme cylinder 11 , Thus, the Anschaltverzögerungs- and pulse duration circuit can be operated with a constant, once determined parameter set, regardless of the surface velocity of the forme cylinder 11 is.

For example, the forwarding and electronic processing of the encoder signal takes place 36 as well as the pixel clock 35 and fine ticks 39 preferably with electronic components that guarantee a deterministic gate term.

In 4 the feint clock is ticking 39 a variety of delay counters 40 the delay unit 32 and a plurality of pulse duration counters 41 the pulse duration shaping unit 33 before each channel control. Each light channel or emitter 34 is each a delay counter 40 and a pulse duration counter 41 assigned. As a result, the delay of each channel in relation to its neighbors as well as the length of the switch-on duration can be parameterized individually via the counter values. The counter values can be determined once and used independently of the speed of the printing surface. With this arrangement, a maximum of one channel offset of one pixel pitch on the printing form can be compensated.

In 4 becomes the location of the memory tap from the cache 31 when reading data about the positioning of a reading pointer 42 and the location of memory access to the cache 31 when storing data about the positioning of a write pointer 45 certainly. An input interface 46 of the cache 31 serves for reading in data and an output interface 47 of the cache 31 is used to output data.

A larger geometric offset of the individual channels to one another can be achieved in a further variant according to the invention in accordance with FIG 5 outlined control architecture. Here each channel is its own cache 31 or FIFO memory assigned whose memory length determines the height of the geometric correction possibility. The location of the memory cell tap, ie the positioning of a read pointer 42 determines the amount of temporal pixel delay of the relevant channel in relation to the adjacent channels. If larger channel offsets occur only between channel sections, z. B. as a result of a production of channel arrays, which are then queued to a larger channel width, the section specific FIFO assignment is conceivable, ie each section or each array is a separate cache or FIFO memory 31 assigned.

These individual FIFO memories 31 be with the pixel clock 35 read out and the individual control signals channel-specific delay counters 40 and pulse duration counters 41 fed. These will turn with the fine clock 39 clocked. This variant also allows parameterization of the delay counters 40 regardless of the selected surface speed of the printing plate.

Alternatively to the previously listed variant of 5 can a greater delay in the control of each channel to each other also by shift registers 43 , as in 6 listed, can be achieved. In this case, the image data is from a FIFO memory 31 with the pixel clock 35 read out and with the hochfrequenteren Feintakt 39 in channel-specific shift registers 43 written which is the delay unit 32 form.

In this shift register 43 The binary image data in each Feintaktzyklus one memory location are moved further, so that each image data bit the entire memory length of its associated shift register 43 once through. The drive signals for a channel become from any memory cell, ie from any position within this individual shift register 34 , tapped.

By means of a pulse generator 41 , who also about the feintakt 39 can be clocked, the pulse length of the emitted beam can still be formed channel-individual. By the size of the shift register 43 can, adjusted to the ratio of fine tact 39 at pixel rate 35 to scale the maximum delay of a channel. To ensure a height adjustment of the pixels orthogonal to their ideal image line over an entire pixel pitch, the shift register should 43 have at least one storage depth of K elements.

If the activation duration of an emitted light beam requires an even higher temporal resolution, the pulse for the pulse duration shaping unit can 33 via a separate frequency multiplication of the pixel signal 35 be won.

This can either be done separately for fine clock generation in the encoder interpolation unit 44 respectively or the Feintaktzeugung be downstream, ie there is a further frequency multiplication of the fine clock 39 instead of. In this clocking principle of the pulse duration shaping unit 33 their parameterization remains independent of the selected surface speed of the printing form 11 ,

Alternatively to the in 5 and 6 a geometrical offset of adjacent channels, which goes beyond the pixel spacing, can also be directly compensated in the image data.

For this purpose, the known or measured deviation measure of individual or multiple channels of the imagesetter control 21 be known. The imagesetter control 21 Then, by shifting and extending the bit patterns, then arranges the frame data information to compensate for individual geometry properties for high quality imaging.

exemplary This image data manipulation is again on a rectangular figure described, their representation in a bitmap file simplified already reproduced in Table 3 below is, which corresponds in principle to Table 1.

In Table 3 below, however, is additionally the relative Arrangement of the light channels to each other strongly outlined deposited. The snapshot is intended to control the light channel line illustrate the image data from line 3.

Tabelle 3

Table 3

From the ideal imaging line orthogonal deviating pictures the light channels that go beyond a pixel pitch, can be corrected by manipulating the image data.

These The aim of manipulation is to temporally over it offset control of the individual channels an effective Activation of the pixels in the desired illustration line to reach. This can be the effective size the image data file can be extended.

The following Table 4 shows an example of the resulting arrangement of the image data extract from Table 3 to compensate for a light spot offset. The form of a projected light point arrangement to be compensated is listed superimposed in Table 3 in the form of strongly framed fields. Row column 1 2 3 4 5 6 7 8th 9 10 1 0 0 0 0 0 1 0 0 0 0 2 0 0 0 1 0 0 0 0 0 0 3 0 0 1 1 1 0 0 4 0 0 1 0 1 0 0 1 0 0 5 0 0 1 0 0 0 0 1 0 0 6 0 0 1 0 1 0 1 0 0 7 0 0 1 1 0 0 0 1 0 0 8th 0 0 1 1 1 0 0 9 0 0 0 0 1 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 Table 4

This image data manipulation may be the restructuring of the image data for its output in the form of a helix using an imaging device 10 to 1 be stored upstream or upstream. Row column 1 2 3 4 5 6 7 8th 9 10 1 0 0 0 0 1 0 0 0 0 2 0 0 0 1 0 0 0 0 0 0 3 0 0 1 0 1 1 0 0 4 0 0 1 0 1 0 0 1 0 0 5 0 1 0 0 0 1 1 0 0 0 6 0 1 0 0 0 1 1 0 0 0 7 1 1 0 1 0 0 0 0 0 0 8th 1 0 1 0 0 0 0 0 0 9 0 1 0 0 1 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 Table 5

In the above Table 5, the result of the required image data manipulations is summarized, which includes both the data output in the form of a helix and the compensation of light spot offsets of the imagesetter 13 to achieve a distortion-free reproduction of the screened image on the printing form 12 considered.

These Image data manipulation steps can in turn be supplemented to avoid image rendering errors such as B. pillow or keystone distortion or to compensate for fan-out effects. In addition, you can still spreads or scaling of the print image further process steps in the whole chain of image data processing.

In another variant of the invention the image data directly by the frequency ratio factor K stretched, d. H. each pixel line entry will be in the image data K-deposited.

After an optionally compressed transmission of this stretched data in the buffer 31 the imaging device 10 can do this directly with the feintakt 39 from this cache 31 be read out and forwarded via the pulse duration shaping unit for controlling the light channels. The image data thus present in the resolution of the fine clock can in turn be manipulated in such a way that fine corrections of the activation of the individual points of light for shifting the imaging point in the image plane below the pixel spacing are achieved.

The factor K determines the minimum discretization level of the geometric correction possible ness. If the invention is applied to the entire image data file, this increases by a factor of K. By compressing this data, the required storage volume can be greatly reduced.

Farther can not extend the data to the entire image data file, but partially transferred to the currently in the buffer Pixel line and directly following lines are applied. The Data manipulation for the correction of geometric offsets smaller the pixel pitch in the image plane is only on the currently read-out and data-multiplexed line, possibly also their directly following lines, applied.

Since these data lines, optionally compressed, are forwarded directly to the buffer of the imaging device, these data operations can advantageously be carried out directly in the main memory of the imagesetter controller 21 respectively. On the basis of the image data manipulation, a parameterization of the functional units is possible independently of the selected surface speed of the printing form.

In particular, the upper variant of the invention is suitable for arrangements in which the functional units imagesetter 13 and imagesetter control 21 form an assembly, ie the image data need not be transferred from a functionally separate unit via a high data rate data link, optionally with the use of compression techniques, during imaging between these devices.

In this solution, the image elements created in an imaging cycle on the printing form can also be used in this solution 12 only parts, extracts or sections of the entire print image include. In this case, either the relevant image extracts are completely loaded onto this module or only image data sections of the data transmitted to the module are forwarded to the light channels. The image data transmission to the module can take place before the exposure process or in parallel to this process.

The different drive architectures from previous points can also be used mixed.

The assignment of the featured functional elements to the aggregates exposure control 21 and imagesetters 13 can be carried out differently advantageous depending on the application. In this case, the functional separation of imagesetter control 21 and imagesetters 13 be completely canceled, ie the exposure control 21 including interface 23 and imagesetters 13 form a functional unit.

In another application of the invention, the density of the adjacent imaging points in the imaging line can be increased. According to 3 this is the line 20 the light channels of the imagesetter 13 with an interchannel distance of d tilted by an angle α.

By a drive delay of the individual imaging channels, the tilted light channel line 20 be projected into the desired Bebilderungsstraade. This reduces the distance of the individual pixels to x = d · cos (α) and thus increases the density of the pixels to each other. This can be used to fix banding effects.

Furthermore, the invention can be realized for triggering a cascade of a plurality of imaging heads, each of which may contain a plurality of light channels. By a series of several imagesetters 13 Side by side, a larger track width of the imaging can be achieved, which can be achieved a much shorter imaging time. 7 shows a possible arrangement of several multi-channel or single-channel imagesetters 13 , Exceeding in this arrangement, the light channel rows to each other in relation to the pixel spacing large distances, is suitable for. B. the above-described image data manipulation to compensate for the light channel distances.

10

The imaging

11

cylinder

12

printing form

13

imagesetter

14

emitter level

15

Light exit position

16

imaging optics

17

projection plane

18

light spot

19

Bebilderungslinie

20

emitter line

21

imagesetter

22

Image data storage

23

image data

24

interface

25

interface

26

storage medium

27

storage medium

28

Restructure Data Unit

29

edited image data

30

unit

31

cache

32

delay unit

33

Pulse duration shaping unit

34

emitter

35

Pixel Clock / interpolated encoder signal

36

original encoder signal

37

Enkoderinterpolationseinheit

38

encoder

39

fine clock

40

delay counter

41

pulse generator

42

read pointer

43

shift register

44

Enkoderinterpolationseinheit

45

write pointer

46

Input interface

47

O interface

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10124215 A1 [0006]

Claims (7)

Imaging device for imaging one on a cylinder ( 11 ) positioned printing form ( 12 ), with at least one imagesetter ( 13 ) and at least one exposure controller ( 21 ), wherein the or each imagesetter ( 13 ) several emitters ( 34 ), the exposure beams for exposure of the printing form ( 12 ), and wherein the or each imagesetter ( 13 ) during exposure relative to the printing form to be exposed ( 12 ) linear and the printing form to be exposed ( 12 ) relative to the or each imagesetter ( 13 ) is rotatably movable, characterized in that: a) the or each exposure controller ( 21 ) Image data ( 23 ) from an image data device ( 22 ), read in the image data ( 23 ) in a data restructuring unit ( 28 ) and resulting image data ( 29 ) the respective imagesetter ( 13 ) for further processing; b) the respective imagesetter ( 13 ) the resulting image data ( 29 ) in at least one cache ( 31 ), where output data of the or each buffer ( 31 ) after passing a delay unit ( 32 ) and a pulse duration shaping unit ( 33 ) as drive signals for the emitter ( 34 ) of the respective imagesetter ( 13 ) serve; c) a unit ( 37 ) of the respective imagesetter ( 13 ) from an encoder signal ( 36 ) of a cylinder ( 11 ) associated encoder ( 38 ) via an interpolation as read-out clock for the respective cache ( 31 ) a pixel clock ( 35 ), which determines the resolution of the encoder ( 38 ) to the desired resolution of the exposure; d) a unit ( 44 ) of the respective imagesetter ( 13 ) from the pixel clock ( 35 ) a higher frequency fine act ( 39 ) which generates a fixed phase coupling to the pixel clock ( 35 ), wherein the fine clock ( 39 ) the delay unit ( 32 ) and the pulse duration shaping unit ( 33 ) triggers emitterindividuell. Imaging device according to claim 1, characterized in that each emitter ( 34 ) of the respective imagesetter ( 13 ) an individual buffer ( 31 ) assigned. Imaging device according to claim 1, characterized in that the emitters ( 34 ) of the respective imagesetter ( 13 ) a common cache ( 31 ) assigned. Imaging device according to one of claims 1 to 3, characterized in that the unit ( 37 ) of the respective imagesetter ( 13 ) the pixel clock ( 35 ) generated by the fact that the encoder signal ( 36 ) is multiplied by a factor X, where X = (A / 25.4 mm / in) · (U / I EFF ) where A is the desired image resolution in dpi, where U is the circumference of the cylinder 11 in mm and where I _EFF effective encoder pulses per revolution of the cylinder 11 are. Imaging device according to one of claims 1 to 4, characterized in that the delay unit ( 32 ) of the respective imagesetter ( 13 ) emitter-individual delay counters ( 40 ) and the pulse duration shaping unit ( 33 ) of the respective imagesetter ( 13 ) emitter-individual pulse duration counters ( 41 ), which is the fine act ( 39 ) triggers emitterindividuell. Imaging device according to one of claims 1 to 4, characterized in that the delay unit ( 32 ) of the respective imagesetter ( 13 ) emitter-individual shift registers ( 43 ) and the pulse duration shaping unit ( 33 ) of the respective imagesetter ( 13 ) emitter-individual pulse duration counters ( 41 ), which is the fine act ( 39 ) triggers emitterindividuell. Imaging device according to one of claims 1 to 6, characterized in that it is the driving of a cascade of several imagesetters ( 13 ), which preferably each contain a plurality of light channels, serves.