HK1050571B - Image-making device with vcsel light resource array for machine plate - Google Patents

Description

Imaging device for printing plates with a VCSEL light source array

Technical Field

The invention relates to a device for producing images on a printing plate, comprising a VCSEL light source array and a projection optics for producing (n x m) image points on the printing plate, wherein n and m are natural numbers, n > 1, and m ≧ 1.

Background

The time for producing an image on a printing plate in a plate exposer or in a printing unit is determined primarily by the number of available image production channels (bellterungskanal). Accordingly, a typical imaging device has a plurality of light sources, wherein at least one light source is arranged corresponding to one imaging channel. An image point is projected on the surface of the printing plate through an image making channel, so that the printing point can be landed on the printing plate. The literature, which contains a large number of articles, relates to the production of images on printing plates using multiple beams of radiation.

For example, US 5,291,329 discloses a device for recording video, in which a plurality of two-dimensionally distributed laser light sources are projected onto a recording surface by means of a projection optics in order to generate a plurality of image points. Typically, the laser source is arranged in a fan-shaped region of a spherical housing, so that the main beam of each laser beam extends through the focal point of the first lens of the projection optics.

In order to achieve a small separation between the image points, a two-dimensional array of individual multimode laser diodes with individual collimating lenses is described in US 5,995,475. The array is projected onto the imaging medium with a substantial reduction in size. The projection optics comprise an anamorphic optical element for shaping the diverging laser beam into a beam shape.

Common to these imaging devices is that they use edge-emitting diode lasers for generating the laser radiation. However, edge-emitting diode lasers have the disadvantage that their laser beam has a large divergence angle and a high astigmatism, so that the beaming of the laser beam is very complicated and in most cases expensive optical lens systems have to be used. Furthermore, edge-emitting diode lasers must first be folded off the wafer and mounted before functional testing. Part of this manufacturing process is very laborious and therefore results in a reduced production margin and an increased laser cost.

Conventional semiconductor lasers are edge emitters, the propagation of light occurs perpendicular to the pn junction surface, and light emerges perpendicularly from the cleaved surface of the wafer. So-called Surface-Emitting Laser diodes (VCSEL Laser diodes) are also known, which emit perpendicularly to the wafer Surface, with the resonator axis parallel to the pn junction Surface. In the context of these descriptions and the inventive device, a VCSEL light source is understood to be all diode lasers whose emission direction is perpendicular to the active region. In this case, it can be in particular surface-emitting lasers in which the resonator length is less than the thickness of the active region, surface-emitting lasers in which the resonator is overall longer, or surface-emitting lasers with an external or coupled resonator (also known as NECSELs). Furthermore, a VCSEL light source can be a diode laser whose resonator is essentially parallel to the active region and is provided with a diffractive or reflective structure which couples out the laser radiation perpendicularly to the active region.

It is generally appropriate for VCSEL sources that the effective length of the resonator can be very short, typically only a few micrometers, and that high reflectivity resonator mirrors are required in order to obtain a small threshold current. Surface emitting laser diodes, i.e. VCSEL light sources, have a number of interesting properties. A large longitudinal module spacing is obtained by a very short resonator, typically below 10 microns in length, which promotes single mode emission above the laser threshold. A circular near field and a small beam divergence determined by a relatively large diameter are obtained by a typical rotationally symmetric resonator with a diameter of 6 to 8 microns. Furthermore, the design of the laser allows a simple integration of a two-dimensional VCSEL laser diode array in its entirety. Finally, testing of such lasers can be performed directly on the wafer after fabrication.

Typical layered structures of surface-emitting lasers are known to the expert and can be found in the corresponding literature (see, for example, "integration optelektronik" by k.j. ebeling, 1992, berlin Springer press). A two-dimensional array of individually addressable or controllable VCSEL light sources is described, for example, in EP 0905835 a 1.

But typical VCSEL light sources have only a small output power. In order to increase the achievable output power and to force laser oscillations in the fundamental mode, a special oscillator form for VCSEL layer structures is disclosed in US 5,838,715. The disadvantage of the above-described forms is, however, firstly the production effort.

In this connection, it is also known from the literature that the light emitted by a plurality of light-emitting diodes is brought together by means of corresponding projection light in order to generate an intense light beam. It is for example described in US 5,793,783 how light from a plurality of light sources or a sub-array of light sources in an array can be focused to an overlapping focal point.

Furthermore, it is common in the literature, for example from US 5,477,259, that an array of light sources can be combined from individual sub-array modules. This typically involves a row, i.e. a one-dimensional distribution of laser diodes, which are fastened side by side to a receiving element, thus forming a two-dimensional array of light sources.

The production of images with one-or two-dimensional arrays of image points on a printing plate typically proceeds according to two types of production imaging methods. The first method is based on the fact that the image light sources are arranged with their image points densely. In other words, the pitch of the dots of the image is equivalent to the pitch of the printed dots to be landed. By moving in two linearly independent directions that spread the surface, a two-dimensional plate of the image to be produced is depicted. The second type of image making method is characterized in that the distance between image points is larger than the distance between adjacent printing points to be landed. Thus, in order to achieve full image creation on a two-dimensional printing plate, it is required that the pixels of one defined image creation step fall between the pixels of the previous image creation step. This method is also called an interleaving method. US 4,900,130 is an example of such an interleaving method. In this document, one-dimensional and two-dimensional grid scan line interleaving methods for a one-dimensional or two-dimensional light source array are disclosed, the image points of which land on the image-forming medium at a greater distance than adjacent printed points.

Disclosure of Invention

The object of the present invention is therefore to provide a device for producing images on printing plates, which can be written by means of a plurality of imaging channels, the light of which has advantageous beam properties and the focal point of which can be produced by a simple light tool. Furthermore, a long system life can be achieved and maintenance in the event of partial failure can be relatively simple.

This object is achieved by an apparatus for producing an image on a printing form having the following features. The features of an advantageous embodiment and an expanded configuration of the device according to the invention are given below.

The device for producing an image on a printing plate according to the invention has a light source array and a projection optics for producing (n x m) image points on the printing plate, where n and m are natural numbers and n > 1 and m ≧ 1. The device is characterized in that the light source array comprises an array of (r x s) VCSEL light sources, at least two of which can be controlled independently of each other, wherein r and s are natural numbers and r ≧ n and s ≧ m. Surface emitting diode lasers (VCSELs) have beneficial radiation characteristics. Rays with small divergence angles are emitted due to the expansion of the emitting surface. The radiation quality and the shape of the emitted radiation are substantially determined by the size of the outcoupling surface. By selecting a specific size, a VCSEL beam (gaussian beam) is generated in the fundamental mode of the resonator, which is particularly advantageous for imaging printing plates due to the high depth of field. In contrast to edge-emitting lasers, the ray diameter and divergence angle are the same in the direction of the linearly independent expanded ray diameter, so collimation and focusing can be achieved with relatively simple optical elements (less asymmetric and/or aspherical elements) which may also be microlens arrays. By suitable contacting of the individual VCSELs in the array, it is ensured that the individual lasers can be controlled individually and independently of one another, so that the light intensity in the imaging channels, which are arranged in correspondence with the VCSEL light sources, can be varied.

In other words, an important idea of the invention is to use a VCSEL array for imaging on a printing plate, wherein a sufficiently high output power is generated for each imaging channel by the VCSEL transmitter in an advantageous resonator module. By means of an individually controllable array, the pixels can be provided in each imaging channel with an intensity corresponding to the imaging information requirement. In order to achieve a higher output power per imaging channel, it is advantageous to propose additional modules in addition to the fundamental mode of the resonator.

In particular, in order to increase the available power, the device for producing images on printing plates can be embodied in such a way that at least one image point on the printing plate is produced by collecting light emitted by a partial array of (r × s) VCSEL light sources, that is to say by at least two VCSEL light sources. By configuring a plurality of VCSEL light sources corresponding to one imaging channel in this way, the margin and the service life of the system are advantageously increased. When one VCSEL light source fails, other VCSEL light sources are available in an image production channel.

It is particularly advantageous if the device for producing images on printing plates is provided with a VCSEL light source array which is composed of a plurality of subarray modules. In other words, the total array of (r × s) VCSEL light sources may consist of individual strips or blocks, each containing a plurality of VCSEL light sources, e.g. s blocks with r surface emitters. Certain light sources can be replaced quickly, simply and economically in the event of partial failure thereof.

Advantageously, the printing plate has a row of n pixels with an adjacent dot spacing of 1.

In a further embodiment of the device according to the invention, which produces an elliptical focus on a printing plate, preferably with an ellipticity of at least 1%, due to the elliptical geometry of the surface emitter or due to a suitable light fixture, it is possible in this embodiment to achieve a higher energy density by means of a transverse (minor-axis) ray of the ellipse and a more favorable temporal energy input coupling in the printing plate by means of a longitudinal (major-axis) ray of the ellipse, depending on the direction of movement, than by using a circular ray which produces the same line width.

It is characteristic of VCSEL arrays that the substrate edge is free and does not function as an emitting surface as an edge-emitting laser. These edges can be machined very precisely so that the individual arrays can be positioned relative to each other. This makes it possible to arrange a plurality of one-dimensional or two-dimensional VCSEL arrays into one larger array, i.e. a plurality of sub-arrays into one (r x s) array of VCSEL light sources, wherein the regular transmitter geometry extends over the entire array. This allows a very large array to be obtained by modular construction, wherein, in the event of a single emitter on one module failing, the failure can be overcome by replacing only the relevant module.

Good cooling can be achieved if, in an advantageous embodiment of the device according to the invention for producing images, the VCSEL p-region is mounted facing downward (on a mount or a receiving element).

The two-dimensional arrangement of VCSEL light sources is determined by a uniform, approximately one-dimensional heat flow, the thermal resistance of which is lower than that of an edge-emitting diode laser array. The contact area between the heat-generating region and the heat sink is typically 0.1cm when using edge-emitting diode lasers²And typically 1.0cm when using a VCSEL array²。

It is to be mentioned in this connection that VCSELs, in contrast to edge-emitting diode lasers, furthermore have a relatively good reproducible ageing state. E.g. less sudden failures due to surface damage. This means that the overall lifetime of the VCSEL array is long, since all emitters are likely to fail after a long time; in contrast to surface damage by edge emitters, this surface damage occurs at a rate that is almost independent of aging. This reproducible ageing can advantageously be used by testing the power of one reference emitter, so that power losses due to ageing of the reference emitter and a set of correspondingly configured emitters can be compensated for without the power of the individual emitters having to be determined or measured.

In addition to the above-described scalability of the preferably individually controllable VCSEL array, it is of great interest that, due to the system-inherent properties of the VCSEL array, a lower-cost device is obtained compared to devices using edge-emitting laser diodes. In addition, the geometry of the VCSEL array is significantly smaller, so that a very compact imaging device for printing plates can be created.

In respect of the incoherent focusing of the light of at least two VCSEL light sources at the same point in an imaging channel, it is advantageous to control the VCSEL light sources in the partial array assigned to the imaging channel in such a way that the light emitted by one VCSEL light source has a fixed phase relationship with respect to the light emitted by a second VCSEL light source. A radiation having a high radiation quality and a high output power can be formed by making full use of the structural interference effect. In order to generate a defined image point, it is therefore necessary in this case to simultaneously control the respective VCSEL light sources. In other words, a plurality of emitters, i.e. VCSEL light sources, are grouped into one imaging channel.

The device according to the invention for producing an image on a printing form can be used particularly advantageously in a plate exposer or in a printing unit. It can be a plate exposer, but also a printing plate received on a curved receiving element, for example a cylinder. For the purpose of making an image, the two-dimensional surface of the printing plate is depicted by the image points of the device in a fast and a slow feed direction (linearly independent directions, not necessarily perpendicular to each other). The printing press according to the invention comprises at least one sheet feeder, a printing unit and a delivery (sheet-fed printing press), at least one printing unit of which has the device according to the invention for producing images on printing plates. Alternatively, a printing press for processing a web can have an apparatus according to the invention. The printing press is preferably a direct or indirect offset printing press, in particular an offset printing press.

The two-dimensional arrangement of the array can be advantageously carried out in such a way that the r columns (with s VCSEL light sources) are oriented substantially perpendicular to the fast feed direction and the s rows of the array are oriented substantially perpendicular to the slow feed direction. If the spacing of two adjacent surface emitters is q and the spacing of two lines on the printing plate is d, then preferably s is q/d. In order to produce an x-fold excess, s is preferably x q/d. In a geometric arrangement in which the maximum separation in the fast-forward direction of the two VCSEL light sources writing adjacent lines is less than s x q, low sensitivity to array inversion and small control errors in time can be achieved.

1:1 imaging can be achieved by using a very large array, for example, made up of a number of sub-array modules. In other words, the entire image area of the printing plate to be produced with a certain number of printing points is exposed by means of the same number of image production channels. This is advantageous in order to achieve a very fast plate exposer, in particular in the case of plate exposures. Due to the favorable radiation characteristics of VCSEL light sources, it is possible to use a relatively simple projection optics or to produce images directly without projection optics when the image production distance is small.

Advantageously, the at least one first light source is a reference emitter of one of the sub-arrays, and the input power is the input power of at least one further light source of the one sub-array when the output power deviates from a nominal value.

Advantageously, at least one light source of the VCSEL light source array produces short pulse radiation.

It is worth mentioning that the printing form not only relates to a conventional printing form, such as a conventional heat-sensitive printing form, but also to a rewritable printing form, a printing film or a film. When using printing plates for digitally imaging, the sensitivity of which is limited to a certain wavelength of the imaging light, VCSEL light sources with corresponding emission wavelengths have to be used. In certain applications, it may be advantageous to use these VCSEL light sources not in CW mode, i.e. for emitting continuous radiation, but for generating short-pulse radiation.

Drawings

Further advantages and advantageous embodiments and developments of the invention are given by the following figures and the description thereof. Specifically, the following steps are shown:

FIG. 1 is a schematic diagram of an apparatus of the present invention for producing an image on a printing plate having an array of VCSEL light sources and a projection optics for producing image spots on the printing plate;

FIG. 2 is a schematic representation of an advantageous embodiment of the device according to the invention for producing images on printing plates, with a VCSEL light source array and a projection optics, which comprises a plurality of partial arrays, which has individual components;

FIG. 3 is a schematic view of another embodiment of the apparatus of the present invention for producing an image on a printing plate, having an array of VCSEL light sources and a projection optics, the array comprising a plurality of sub-arrays, the projection optics having individual components;

FIG. 4 is a schematic illustration of an embodiment of a VCSEL light source array consisting of subarray modules in the device according to the invention for producing images on printing plates;

FIG. 5 is a schematic diagram of an embodiment including a reference transmitter output power detection layout, in the apparatus of the present invention having a VCSEL light source array composed of subarray modules;

fig. 6 shows a schematic representation of the use of the device according to the invention with a printing plate mounted on a cylinder.

Detailed Description

Fig. 1 shows a schematic representation of an inventive device for producing images on a printing plate, having a VCSEL light source array and a projection optics for producing image points on the printing plate. The light source array 10 has individual emitters that contain VCSEL light sources 12. These VCSEL light sources have, for example, a pitch p, and in the usual case the pitch of the emitters can also be different in two linearly independent directions spreading the surface. For example, fig. 1 shows an array of 3 × 5 VCSEL light sources 12, but in the general case the array 10 contains n × m VCSEL light sources 12, where n and m are natural numbers.

Image points 18 are generated on a printing form 16 by means of a projection optics 14, which have an adjacent image point spacing 1. In this case, it is immaterial to the nature of the device according to the invention whether the adjacent dot spacing 1 is equal to the printing dot spacing p to be printed or whether an adjacent dot spacing 1 is involved which is greater than the printing dot spacing p of the image to be produced. In this case, the image point is moved relative to the printing plate in such a way that the image is produced in an interlaced manner.

The VCSEL light sources 12 of the light source array 10 may be individually controlled. An imaging beam 110 of a VCSEL light source 12 representative of this is shown here. The light source array 10 is disposed on a power supply unit 112. The power supply unit 112 is connected to a control unit 116 via a connection 114 for exchanging data and/or control signals. As described above, devices, not shown in fig. 1, are provided here, which move the printing plate 16 relative to the image points 18 of the light source array 10 in order to deposit printing points on the printing plate 16. To densely fill a two-dimensional area of printing plate 16, a movement is defined in both a first direction 118 and a second direction 120 that spreads the surface of printing plate 16.

In a particularly advantageous embodiment of the invention, it is provided that the light source array 10 is arranged in such an expanded manner in one dimension of the two-dimensional printing form that the printing form is flat or at least partially curved, that the entire format width or page width, that is to say at least the width of the printing area on which the image is produced on the printing form 16, can be imaged substantially parallel. This allows the movement of the device in this direction for the production of images to be dispensed with, so that the production of images can be carried out quickly and accurately.

Fig. 2 shows a schematic representation of an advantageous embodiment of the device according to the invention for producing images on printing plates, with a VCSEL light source array and a projection optics, which comprises a plurality of partial arrays, which has individual components. Fig. 2 shows a light source array 10 containing individual VCSEL light sources 12, a projection optics 14 with individual components 122, and a printing plate 16. A subset of the total set of VCSEL light sources 12 forms a sub-array 124. Typically, these sub-arrays 124 oppose each other and complement each other into an overall set of VCSEL light sources 12. Fig. 2, for example, shows a light source array 10 of 3 × 5 VCSEL light sources 12. In the usual case, a light source array 10 is provided which is composed of n × m VCSEL light sources 12, where n and m are natural numbers. For example, a sub-array 124 comprises a column of three VCSEL light sources 12, i.e. in three different rows. Projection optics 14 are embodied here in part 122 in such a way that the light rays emitted by a partial array 124, in this case the image-producing light beam 126 of the partial array, are focused into an image point 18 on the printing plate. In other words, the VCSEL light sources 12 of a particular sub-array 124 are light sources for producing an imaging channel of an image spot 18 on the printing plate. As already mentioned elsewhere, it is immaterial in this connection whether the adjacent pixel pitch i on the printing plate is equal to or greater than the adjacent printed dot pitch p. The partial arrays 124 of the light source array 10 are preferably embodied in such a way that the light emitted by the VCSEL light sources 12 of the partial arrays 124 is focused into image points 18 on the printing plate 16, which image points 18 are located substantially in a straight line on the printing plate. This creates a set of image points that can be moved across printing plate 16 in linearly uncorrelated directions along the surface on which printing plate 16 is spread in order to produce grid scanlines or imaging lines on printing plate 16.

Fig. 3 shows a schematic representation of a further embodiment of the device according to the invention for producing images on printing plates, with a VCSEL light source array and a projection optics, which comprises a plurality of partial arrays, which has individual components. The device for producing images on printing plates comprises a light source array 10 with VCSEL light sources 12, a projection optics 14 with individual components 122, and a printing plate 16. For example, fig. 3 shows an array of 3 × 6 VCSEL light sources 12. Here, the light source array 10 has, for example, two 3 × 3 sub-arrays 124. Projection optics 14 are embodied such that a component 122 collects imaging radiation 126 of a sub-array 124 in a beam at an image point 18 on printing plate 16.

In an advantageous embodiment of the invention shown in fig. 2 or 3, at least one component 122 of the projection optics 14, which acts on a partial array 124 of the array 10 of VCSEL light sources 12, can also be implemented as a micro-optic. It is particularly advantageous that these parts 122 can be moved relative to one another.

Fig. 4 shows a schematic illustration of an embodiment of the device according to the invention for producing images on printing plates with a VCSEL light source array composed of subarray modules. The light source array 10 with the VCSEL light sources 12 is composed here, for example, of three light source modules 128, each of which light source modules 128 has five VCSEL light sources 12 arranged in a row. The light source modules 128 are arranged next to one another in such a way that a 3 × 5 light source array 10 is formed. It is preferable to use the surface of the power supply unit 112 of the light source array 10 as the receiving member 130. A reference emitter 132 may be determined for a light source module 128. The reference transmitter 132 is provided for detecting parameters that are significant for transmission. These parameters of significance for the emission are, for example, the supply current or the VCSEL light source output power.

Fig. 5 shows a schematic diagram of a further embodiment with a VCSEL light source array composed of subarray modules, including the output power detection arrangement of a reference transmitter. The apparatus for producing an image on a printing plate comprises a light source array 10 with VCSEL light sources 12, a projection optics 14 with individual components 122 and a printing plate 16. In the illustrated embodiment, the 3 × 6 VCSEL light source 12 array 10 is composed of two light source modules 128. These light source modules 128 each have 3 × 3 VCSEL light sources 12. One surface of the power supply unit 112 functions as a receiving member 130. The power supply unit 112 is kept connected to a control unit 116 by means of a connection 114 for exchanging data and/or control signals. A reference emitter 132 is provided on one of the light source modules 128. For example, it is shown here that the reference emitter 132 emits an imaging beam 134 for imaging the printing plate 16. A portion of the emitted light of the image-forming beam 134 is outcoupled and diverted to a detector 138 by means of a beam splitter 136 having a known splitting ratio. The signal from the detector 138 is passed via a connection 140 to the control unit for further processing. A regulation can thus be achieved by which the input power of at least one VCSEL light source, here the reference emitter 132, is changed as a function of the output power of the light source when the output power deviates from a nominal value. Furthermore, a reference emitter 132 of a partial array 128 of the array 10 of VCSEL light sources 12 can be used in the regulation in such a way that the input power of at least one further VCSEL light source of the partial array 128 is changed as a function of the output power of the reference emitter 132 when the output power deviates from a setpoint value.

It is also particularly advantageous if at least one component 122 of the projection optics 14 for a partial array 128 of the VCSEL light source array 10 can be moved in a displacement direction 142 in such a way that the position of the focal point arranged behind can be varied as a function of the distance of the array of VCSEL light sources 12 from the printing plate 16. In this connection, it is known to the expert that the measured distance between the light source 12 and the printing plate 16 can be used as an input variable in an autofocus device, in which case the device according to the invention for producing images on printing plates can be advantageously extended.

Instead of the output power detection arrangement shown in fig. 5, the output power of the at least one reference emitter 132 can also be measured directly on the VCSEL light source 12 on one resonator mirror.

In fig. 6, the image is shown being made on a printing plate which is positioned on a rotatable cylinder. In this case, the light source array 20 with VCSEL light sources 21 generates, for example, three imaging light beams 22, which are projected onto three image points 210 by means of a projection optics 24. The image points are advantageously equally spaced from one another and lie on an axis. The printing plate 28 is located on a cylinder 26, which cylinder 26 is rotatable about its axis of symmetry 25. This rotation is indicated by arrow B. The array of light sources 20 can be moved in a substantially linear path parallel to the drum axis of symmetry 25, which is indicated by the double arrow a. In order to produce images continuously or in pulses, the cylinder 26 with the printing plate 28 is rotated in a rotational movement B and the light source array 20 with the power supply unit 23 is moved in the longitudinal direction of the cylinder in the direction of movement a. This results in an image being made on the spiral path 212 around the axis of symmetry 25 of the cylinder 26. The path of the image point 210 is represented by line 212. In other words, after the image has been produced at three points in this case, the printing plate 28 and the image points 210 are moved relative to one another by a first determined amount with a vector component perpendicular to the direction determined by the straight line formed by the three image points, so that the next three points can be rewritten at another position of the printing plate 28. This results in so-called "grid scan lines" of image points. For each defined adjacent grid scanning line distance, i.e. adjacent pixel distance 1 and the number of pixels, a defined second value of the necessary movement is generated, which is parallel to the axis defined by the line formed by the three pixels, so that a densely formed image is formed, i.e. an image is formed at each defined printing point on printing plate 28.

In other words, if the light source array 20 is oriented such that n imaging rays 22 are generated, the axes of which are substantially parallel to the direction of movement a, then the n image points 210 move along n helical lines on the drum 26 rotating in the direction B. If one is looking at an azimuth, the n helices are interleaved. When the image points 210 generated by the n spirals are not arranged densely, viewed in this azimuth angle in the direction parallel to the axis of rotation 25, these spirals must have a lift corresponding to the feed rule in the interlaced grid scanning line method in order to avoid double writing of points on the surface of the cylinder 26.

The apparatus for making an image shown in fig. 6 may be implemented on a cylinder 26 in a printing apparatus. Such a printing unit may be a component of a printing press.

Reference numerals

10 light source array 12 VCSEL light source

14 projection optics 16 printing plate

18-pixel 110-system image beam

112 power supply unit

114 connection device for exchanging data and/or control signals

116 control unit 118 first direction of motion

120 second direction of motion 122 component

124 sub-array 126 sub-array image-making beam

128 light source module 130 receiving element

132 reference emitter 134 reference emitter imaging beam

136 beamsplitter 138 detector

140 direction of movement of the connecting means 142

20 light source array 21 VCSEL light source

22-system image beam 23 power supply unit

24 projection optics 25 axis of rotation

26 cylinder 28 printing plate

210 pixel 212 pixel path

q transmitter spacing l adjacent pixel spacing

p printing dot pitch A moving direction

Direction of rotation B

Claims (19)

1. Apparatus for producing an image on a printing plate, comprising an array of light sources and a projection optics for producing n x m image points on the printing plate, wherein n and m are natural numbers, n > 1, m ≧ 1; the method is characterized in that: the light source array comprises an array consisting of r × s VCSEL light sources, at least two of the r × s VCSEL light sources can be controlled independently of each other, wherein r and s are natural numbers, r is larger than or equal to n, and s is larger than or equal to m; the array of r x s VCSEL light sources is modularly constructed from a plurality of sub-arrays.

2. An apparatus for making an image on a printing plate according to claim 1, wherein: the printing plate has at least one defined image point, which is generated by collecting light emitted by one of the sub-arrays of r × s VCSEL light sources.

3. An apparatus for making an image on a printing plate according to claim 1, wherein: the printing plate has a row of n pixels with an adjacent dot spacing of 1.

4. An apparatus for making an image on a printing plate according to claim 2, wherein: the sub-array has at least one first and one second VCSEL light source, which are controlled such that the light emitted by the first VCSEL light source has a fixed phase relationship with respect to the light emitted by the second VCSEL light source.

5. An apparatus for making an image on a printing plate according to claim 1, wherein: the projection optics includes at least one component that acts on at least one of the plurality of sub-arrays and is a micro-optics component.

6. An apparatus for making an image on a printing plate according to claim 1, wherein: one of the sub-arrays has a VCSEL light source as a reference emitter for detecting parameters that are significant for the emission.

7. An apparatus for making an image on a printing plate according to claim 1, wherein: the projection optics have a component whose focal position can be varied as a function of the spacing of at least one light source of the VCSEL light source array relative to the printing plate.

8. An apparatus for making an image on a printing plate according to claim 1, wherein: the VCSEL light source array has at least one first light source having a regulating device that varies an input power as a function of an output power of the first light source when the output power deviates from a nominal value.

9. An apparatus for making an image on a printing plate according to claim 8, wherein: the at least one first light source is a reference emitter of one of the plurality of sub-arrays, and the input power is the input power of at least one other light source of the one sub-array when the output power deviates from a nominal value.

10. An apparatus for making an image on a printing plate according to claim 1, wherein: at least one light source of the VCSEL light source array produces short pulse radiation.

11. A plate aligner, characterized by: the plate exposer comprising at least one device for making images on a printing plate according to claim 1.

12. Printing device, its characterized in that: the printing unit has at least one device for producing images on a printing form according to claim 1.

13. Printing machine, having at least one feeder and one delivery, characterized in that: the printing press has at least one printing unit according to claim 12.

14. Apparatus for producing an image on a printing plate, comprising an array of light sources and a projection optics for producing n x m image points on the printing plate, wherein n and m are natural numbers, n > 1, m ≧ 1; the method is characterized in that: the light source array comprises an array consisting of r × s VCSEL light sources, at least two of the r × s VCSEL light sources can be controlled independently of each other, wherein r and s are natural numbers, r is larger than or equal to n, and s is larger than or equal to m; the array of r x s VCSEL light sources comprises a sub-array of at least two VCSEL light sources, the printing plate having at least one defined image point, said image point being generated by collecting light emitted by said sub-array of r x s VCSEL light sources; and the sub-array has at least a first and a second VCSEL light source, which are controlled such that the light emitted by the first VCSEL light source has a fixed phase relationship with respect to the light emitted by the second VCSEL light source.

15. Apparatus for producing an image on a printing plate, comprising an array of light sources and a projection optics for producing n x m image points on the printing plate, wherein n and m are natural numbers, n > 1, m ≧ 1; the method is characterized in that: the light source array comprises an array consisting of r × s VCSEL light sources, at least two of the r × s VCSEL light sources can be controlled independently of each other, wherein r and s are natural numbers, r is larger than or equal to n, and s is larger than or equal to m; the array of VCSEL light sources has at least one sub-array with a VCSEL light source as a reference emitter for detecting parameters which are relevant for the emission.

16. Apparatus for producing an image on a printing plate, comprising an array of light sources and a projection optics for producing n x m image points on the printing plate, wherein n and m are natural numbers, n > 1, m ≧ 1; the method is characterized in that: the light source array comprises an array consisting of r × s VCSEL light sources, at least two of the r × s VCSEL light sources can be controlled independently of each other, wherein r and s are natural numbers, r is larger than or equal to n, and s is larger than or equal to m; the array of VCSEL light sources has a sub-array, and the projection optics for the sub-array have a component whose focal position can be varied as a function of the distance of at least one light source of the VCSEL light source array from the printing plate.

17. Apparatus for producing an image on a printing plate, comprising an array of light sources and a projection optics for producing n x m image points on the printing plate, wherein n and m are natural numbers, n > 1, m ≧ 1; the method is characterized in that: the light source array comprises an array consisting of r × s VCSEL light sources, at least two of the r × s VCSEL light sources can be controlled independently of each other, wherein r and s are natural numbers, r is larger than or equal to n, and s is larger than or equal to m; the VCSEL light source array has at least one first light source having a regulating device that varies an input power as a function of an output power of the first light source when the output power deviates from a nominal value.

18. The apparatus of claim 17, wherein: the at least one first light source is a reference emitter of a sub-array of the VCSEL light source array, and the input power is the input power of at least one other light source of the sub-array when the output power deviates from a nominal value.

19. Apparatus for producing an image on a printing plate, comprising an array of light sources and a projection optics for producing n x m image points on the printing plate, wherein n and m are natural numbers, n > 1, m ≧ 1; the method is characterized in that: the light source array comprises an array consisting of r × s VCSEL light sources, at least two of the r × s VCSEL light sources can be controlled independently of each other, wherein r and s are natural numbers, r is larger than or equal to n, and s is larger than or equal to m; at least one light source of the VCSEL light source array produces short pulse radiation.