EP1661716B1 - Method of driving a thermal transfer print head - Google Patents

Description

The present invention relates to a method for driving a printhead which operates on the thermal transfer principle with a plurality of printing elements, wherein in a determining step the first amount of energy to be supplied to a first printing element is determined in a first feeding step, in a further determining step to supply the one printing element associated in a further feeding step further amount of energy is determined and in the first supply step, the first amount of energy is supplied to the first printing element to transfer color from a printhead associated ink carrier device to the color carrier associated substrate for generating a pixel of a first printed image and in the further supply step, the further amount of energy associated printing element is supplied to transfer color of the ink carrier device to the substrate for generating a further pixel of the printed image, wherein the printed image a first subarea and a further subarea of different print image type, the first pixel is assigned to the first subarea, and the further pixel is assigned to the further subarea. It further relates to a printer which is suitable for carrying out the method according to the invention.

In such thermal transfer printers, as z. B. from the EP 0 536 526 A2 are known to obtain a high-quality image, the respective printing element of the printhead must be supplied with a comparatively precisely metered amount of energy to reliably melt the color particles in the desired amount or spatial extent of the carrier material of the ink ribbon. Depending on the current temperature of the respective pressure element more or less energy must be supplied to achieve the optimum melting temperature.

The control of the printing elements is usually optimized at the factory to a specific type of ribbon with a particular color. In order to determine the required amount of energy for a respective pixel of the print image to be generated, a predetermined determination algorithm and a correspondingly matched printing parameter set are generally used.

However, there is the problem that there are different requirements for the nature of the pixels generated on the substrate for different types of printed image. Thus, in particular with so-called two-dimensional barcodes, there are high demands on sharpness and contrast in the region of the edges of the rectangles or squares generated over the pixels. This applies both in the direction of printing and across it. In contrast, these stringent requirements for so-called one-dimensional barcodes usually only exist in one direction, usually the printing direction. In the case of text or free graphics, in turn, other requirements have to be met.

In order to meet these different requirements as far as possible, a compromise solution or a solution tailored to a specific type of print image is selected, which, however, leads to unsatisfactory results, for example in partial areas of a mixed print image with different print image types.

On the other hand, although it is possible to select a control of the print head for all print image types, which provides a satisfactory result for the print image type with the highest requirements, as can be seen from the GB 2169 771 A is known, which discloses a method of the type mentioned. However, this is usually undesirable from an economic point of view, since then in areas with lower requirements, a correspondingly increased effort is operated.

The present invention is therefore based on the object to provide a method or a printer of the type mentioned, which or which does not have the above-mentioned disadvantages or at least to a lesser extent and in particular a simple and economical improvement of the print image quality Print images of different print image type allows.

The present invention solves this problem starting from a method according to the preamble of claim 1 by the features stated in the characterizing part of claim 1. It solves this problem further starting from a printer according to the preamble of claim 19 by the features stated in the characterizing part of claim 20.

The present invention is based on the technical teaching that it is possible to easily improve the print image quality in print images of different print image types if the first amount of energy in the determination step is determined as a function of the print image type of the first print image in the region of the first image point.

As a result, it is possible in a simple manner to achieve an optimized print quality for print images of different print image types and mixed print images with regions of different print image types.

The method according to the invention can be used if entire print images are to be printed with in each case changing print image type. However, its use is particularly advantageous when the first printed image subregions different Druckbildart having. The first amount of energy is then preferably determined as a function of the print image type of the subarea to which the first pixel is assigned.

The first amount of energy can be determined in any suitable manner. Thus, different pressure parameters and / or different determination algorithms can be provided to determine the first amount of energy for different types of print images.

For this purpose, it is preferably provided that the first amount of energy in the determination step is determined using a first set of pressure parameters as a function of the print image type at the location of the first image point.

The pressure parameters contained in the pressure parameter set may be any desired parameters which can be used to determine the correct control values for the pressure elements. For example, it may be directly to voltages and / or currents and / or pulse lengths, etc., which could be used directly to control the printing elements. Preferably, the first set of pressure parameters is an energy parameter set, since the corresponding control parameters can be calculated quickly from this independently of the structure of the print head.

In preferred variants of the method according to the invention, it is provided that the first amount of energy is determined in the determination step using a first print parameter set, the first print parameter set having different sub-parameter sets associated with different print image types, and the first amount of energy being determined at least using that sub-parameter set which is the local print image type associated with the first pixel.

In other variants of the method according to the invention it is provided that the first amount of energy is determined in the determination step using a detection algorithm, wherein different print image types associated determination algorithms are provided and the first amount of energy is determined at least using that determination algorithm, which the print image type at the location of the first pixel assigned. For example, the respective determination algorithm can each work with the same set of pressure parameters. In the simplest case, the determination algorithms differ only by factors or summands. However, it can also be provided that the respective determination algorithms differ in their basic structure.

The first amount of energy can be determined in such a way that in each case only the first amount of energy corresponding to the print image type at the first pixel is determined in the determination step. In other words, for a specific print image to be generated in the determination step, a single correct drive set with the first energy quantities can be generated directly for all first pixels of the print image to be generated.

In other variants of the invention, however, it can also be provided that a first amount of energy for several or all different types of print images is determined for the first pixel, and then a selection of the first amount of energy for use in the delivery step takes place in a selection step subsequent to the determination step, which is associated with the printed image type at the location of the first pixel. In other words, for example, for a particular print image with the parameters or determination algorithms for different print image types, a plurality of drive sets having the first amounts of energy for all first pixels of the print image to be generated can be generated. From these control sets, the one which corresponds to the printed image type at the location of the respective pixel is then selected and used at a later time.

In particularly advantageous variants of the method according to the invention, it is provided that first a first print parameter set characteristic of the color carrier device is read from a first store assigned to the color carrier device and the first amount of energy is then determined using at least the first print parameter set.

The assignment of the first memory to the ink carrier device makes it possible to exchange the first memory together with the color carrier device used. Thus, in each case, energy parameters that are precisely matched to the ink carrier device being used can be automatically used in a simple manner. This makes it possible, inter alia, to use color carrier devices with different colors, without the need for a complex modification of the firmware of the control of the print head would be required.

According to the invention, it is therefore provided on the one hand that a first print parameter set characteristic of the color carrier device is read from a first store assigned to the color carrier device in a reading step preceding the determination step, and the first amount of energy is determined in the determining step using at least the first print parameter set.

The first memory may be associated with the color carrier in any suitable manner. It only has to be ensured that the first memory can be read out by the print head drive during or after the assignment of the ink carrier device to the print head. Preferably, the first printing parameter set in the reading step is therefore read from the first memory, which is arranged on the ink carrier device.

The first memory may be any suitable memory that can be read in any suitable manner. For example, it may be one or more electronic, electromagnetic, optical memory modules, etc. Preferably, it is one or more memory chips that can be contacted and read out by suitable means. However, it may also be a, preferably suitably coded, mark whose information content is detected by optical means.

The ink carrier device can likewise be any suitable device with a color carrier carrying the ink to be removed. By way of example, the ink carrier device may be an ink ribbon cassette with a color ribbon as ink carrier.

This ink carrier device may be exchangeable in any suitable manner, i. H. be designed removable from the printhead. If a new color carrier device is assigned to the print head, for example a new color ribbon cassette is used, then, as mentioned, a connection to the first memory is preferably automatically established in order to be able to read out print parameters from the first print parameter set. This can be done for example by corresponding contact elements on the ink carrier device, which are contacted automatically when mounting the ink carrier device to the printer.

Preferably, the first set of pressure parameters comprises at least one first part parameter set, which in turn comprises at least one first pressure parameter as a function of at least one first state parameter prevailing in the region of the print head. This makes it possible to quickly and easily respond to different states of the printer or its environment, for example, to different temperatures or printing speeds.

The first pressure parameter can be stored as a continuous function of the relevant state parameter. In the case of further variants of the method according to the invention, on the other hand, it is provided that the first partial parameter set for a plurality of discrete values of the first state parameter comprises at least one assigned first pressure parameter value, so that, if appropriate, the relevant pressure parameter value can be taken directly from the partial parameter set without further calculations.

In this case, a correspondingly large number of pairs of values can be provided in order to remove the relevant pressure parameter value directly from the partial parameter set with sufficient accuracy. In order to reduce the memory overhead, however, it is preferably provided that intermediate values of the first pressure parameter value are determined by interpolation in the determination step for values of the first state parameter lying between the discrete values of the first state parameter.

The first state parameter can be any state parameter that influences the printing process or its result. Preferably, the first state parameter is a temperature in the region of the printhead, since this has an immediate influence on the additional energy to be expended for printing. Likewise, the first state parameter may be a relative velocity of a medium, for example a substrate to be printed, with regard to the printing element and / or the ink carrier device. This can be, for example, the feed rate of the medium to be printed or the relative speed between the print head and the ink carrier, etc.

As already explained above, the respective printing element must be supplied with a comparatively precisely metered amount of energy during the printing process in order to reliably melt the color particles in the desired amount or spatial extent of the ink carrier. Depending on the current temperature of the pressure element, more or less energy must be supplied in order to achieve the optimum melting temperature.

The current temperature of the printing element can hardly or only with considerable effort determine directly. Among other things, it depends on the temperature of the surrounding areas of the print head. On the other hand, it depends on the previously supplied to the respective pressure element energy. In preferred variants of the method according to the invention is therefore carried out in the determination step or to take place Energy supply to at least the first pressure element in at least one of the first supply step preceding feed step taken into account. With this consideration of the printing history, it is possible to estimate the energy required for the optimum printing with simple means and high accuracy.

Depending on the control of the printing elements, the determination of the energy required for optimum printing can be carried out in advance for the entire print image. In the determination step, the energy supply to be performed at least to the first pressure element is then taken into account in at least one feed step preceding the first feed step. If the determination of the energy required for the optimum printing takes place during the printing process, the energy supplied to at least the first printing element in at least one feed step preceding the first feeding step is then taken into account in the determining step.

It may be sufficient to consider only the respective pressure element. Preferably, however, one or more adjacent printing elements are taken into account in order to estimate the energy supplied by them. Preferably, in the determination step, therefore, the energy supply to be made or to take place is taken into account for at least one second pressure element adjacent to the first pressure element in at least one feed step preceding the first feed step.

In this case, the energy supply which has taken place or is to take place for the pressure element and / or its neighbor is preferably taken into account in the last supply step before the first supply step. Further preferably, the power supply to and / or to the power element and / or its neighbor is taken into account in the penultimate supply step prior to the first supply step. This can be particularly good estimates of the optimal amount of energy to be supplied.

In particularly preferred variants of the method according to the invention with consideration of the print history, it is provided that the first print parameter set comprises a plurality of energy supply values for different energy supply constellations in at least one previous feed step. In this way, the energy value to be supplied to the pressure element can then be calculated in a simple manner as a function of the recorded or registered printed history.

Preferably, in the determining step, the first amount of energy is determined using at least the first set of pressure parameters by a maximum of a predetermined amount of energy to be supplied is deducted for the energy supply in at least one previous supply step to at least the first pressure element. This makes it possible to determine the required optimum amount of energy particularly easily and quickly.

The present invention further relates to a printer having a thermal transfer printing device comprising a printhead having a plurality of printing elements and a processing unit connected to the printhead for driving the printhead. Furthermore, the printer comprises a color carrier device, preferably removable, associated with the print head. The processing unit is configured to determine the first quantity of energy to be supplied to a first pressure element and to trigger the supply of the first quantity of energy to the first pressure element in order to transfer color from the color carrier device to a substrate assigned to the color carrier device for producing a first image point of a first print image. According to the invention, the processing unit is designed to determine the first amount of energy as a function of the print image type of the first print image in the region of the first image point.

This printer is suitable for carrying out the method according to the invention. With it, the advantages and variants of the method according to the invention described above can be realized to the same extent, so that in this regard reference is made to the above statements.

The first printed image preferably has partial regions of different print image types, and the processing unit is designed to determine the first amount of energy as a function of the print image type of the partial region to which the first pixel is assigned. In this case, the processing unit preferably uses at least one first parameter set of pressure parameters.

This first set of pressure parameters preferably has sub-parameter sets assigned to different print-image types, and the processing unit is designed to determine the first amount of energy at least using the sub-parameter set associated with the print-image type at the location of the first pixel. Additionally or alternatively, determination algorithms associated with different print image types can be provided and by which the processing unit can be used to determine the first amount of energy in the manner described above.

In particularly advantageous variants of the printer according to the invention, a first memory assigned to the color carrier device is provided, in which a first print parameter set characteristic of the color carrier device is stored. Furthermore, the processing unit is designed to read the first set of pressure parameters and to determine the first amount of energy using at least the first set of pressure parameters.

Preferably, the first memory is therefore connected to the color carrier device as described above. Furthermore, the processing unit is preferably designed for the above-described determination of intermediate values of the first pressure parameter value for values of the first state parameter lying between the discrete values of the first state parameter by interpolation.

In order to be able to take into account the printing history as described above, the processing unit is preferably designed to take account of the previous energy supply to at least the first printing element. Further preferably, the processing unit is designed to take into account the preceding energy supply to at least one second pressure element adjacent to the first pressure element. In this case, the processing unit is preferably designed to take into account the last energy supply that has taken place and / or to take into account the penultimate energy supply.

Furthermore, the processing unit is preferably designed to read the first memory in a read step triggered by at least one predeterminable event. Such a predeterminable event may be any temporal or non-temporal event. For example, it may be provided that the event is the achievement of certain predefinable times. Likewise, the event may be the occurrence of a specific predefinable operating state of the printer. For example, the reading step may occur every nth power-up (with n = 1, 2, 3, etc.) of the printer. After all, the event can of course also be a specific input from a user or from a remote data center.

The first event is preferably the connection of the first memory to the processing unit. In other words, the reading step is triggered by connecting the first memory to the processing unit. In this way it can be ensured that with each new or renewed insertion of a color carrier device the correct print parameters are read and available for control.

The pressure parameter set or individual pressure parameters can be read out again from the first memory for each control. Preferably, the first set of pressure parameters in the reading step is read from the first memory and stored in a second memory connected to the processing unit, which is then accessed in the further process sequence for the control. As a result, faster processing times can be achieved since such a second memory in the printer, for example, a faster memory, which is often present anyway in the printer, can be addressed faster. The cost of the first memory, especially its fast response, can then be kept low.

The printer according to the invention can basically be used for any desired applications. It can be used particularly advantageously in connection with a franking machine. This applies in particular if, as described above, different print-image type-dependent print parameters are used. In the case of a postage meter machine, this can be used, for example, by using different printing parameters when producing one-dimensional or two-dimensional barcodes than when generating text or free graphics. The printer according to the invention is therefore preferably designed as a printer unit of a franking machine.

The present invention accordingly also relates to a franking machine with a printer according to the invention. Furthermore, the present invention relates to a color carrier device, in particular ribbon cassette, for a printer according to the invention which has the features of the ink carrier device described above in connection with the printer according to the invention. Finally, it further relates to a printing device for a printer according to the invention, which has the features of the printing device described above in connection with the printer according to the invention.

Figur 1

eine schematische Darstellung einer bevorzugten Ausführungsform des erfindungsgemäßen Druckers, mit dem eine bevorzugten Ausführungsform des er- findungsgemäßen Verfahrens zum Ansteuern eines Druckkopfes durchgeführt werden kann;

Figur 2

ein schematisches Ablaufdiagramm einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens zum Betreiben eines Druckers unter Verwendung einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens zum Ansteuern eines Druckkopfes, die mit dem Drucker aus Figur 1 durchgeführt wird;

Figur 3

eine schematische Darstellung eines Druckbilds, das mit dem Drucker aus Figur 1 unter Verwendung des erfindungsgemäßen Verfahrens erzeugt wurde;

Figur 4

ein schematisches Ablaufdiagramm einer Ausführungsform eines Verfahrens zum Betreiben eines Druckers, die mit dem Drucker aus Figur 1 durchgeführt wird.

Further preferred embodiments of the invention will become apparent from the dependent claims and the following description of preferred embodiments, which refers to the accompanying drawings. Show it

FIG. 1

1 is a schematic representation of a preferred embodiment of the printer according to the invention, with which a preferred embodiment of the invention inventive method for driving a print head can be performed;

FIG. 2

a schematic flow diagram of a preferred embodiment of the method according to the invention for operating a printer using a preferred embodiment of the method according to the invention for driving a print head, with the printer from FIG. 1 is carried out;

FIG. 3

a schematic representation of a printed image, with the printer off FIG. 1 was generated using the method according to the invention;

FIG. 4

a schematic flow diagram of an embodiment of a method for operating a printer, with the printer off FIG. 1 is carried out.

FIG. 1 shows a schematic representation of a franking machine 1 with a preferred embodiment of the printer according to the invention 2. The printer 2 is operated according to a preferred embodiment of the method according to the invention for operating a printer. Here is also a preferred embodiment of the method according to the invention for driving a print head use.

The printer 2 represents the printer unit of the franking machine 1. In addition to the printer 2, the franking machine 1 also comprises further components, such as an input / output unit 1.1, a security module 1.2 in the form of a so-called PSD or SAD, in short a so-called SD, and a communication unit 1.3.

Via the input / output unit 1.1, for example a module with keyboard and display, a user can enter information into the franking machine 1 or information can be output to a user. The security module 1.2 provides security functionalities for the physical and logical security of the security-relevant data of the franking machine 1. Via the communication unit 1.3, the franking machine 1 can be connected, for example, via a communication network with remote devices, for example a remote data center.

The printer 2 comprises inter alia a processing unit 1.4, a print head 2.1 and a color carrier device in the form of an ink ribbon cassette 3. The processing unit 1.4 is a central processing unit of the franking machine 1, which, among other functions, controls the printing head 2.1 during printing.

The printhead 2.1 comprises a power supply device 2.2 which supplies a series of n printing elements 2.3, 2.4, 2.5 with energy. The power supply device 2.2 is controlled accordingly by the processing unit 1.4.

The ink ribbon cassette 3 is assigned to the print head 2.1 such that its ribbon 3.1 contacts the printing elements 2.3, 2.4, 2.5 of the print head 2.1 with its rear side. For printing, the printing elements 2.3, 2.4, 2.5 driven by the processing unit 1.4 supplied by the power supply device 2.2 each with a precisely metered amount of energy to melt locally color particles of the ink layer 3.2, which is located on the ink carrier 3.3 of the ink ribbon 3.1. These color particles are then transferred to a substrate 4, here a letter to be franked, transferred. The letter 4 is for this purpose passed past the print head 2.1 and pressed by pinch rollers against the intermediate ribbon 3.1.

The ink ribbon cassette 3 has a first memory 3.4, which is automatically connected to the processing unit 1.4 when the ink ribbon cassette 3 is assigned to the printer 2, in other words when the ink ribbon cassette 3 is inserted into the franking machine 1. In the first memory 3.4, the ink ribbon cassette 3 associated printing parameters are stored as a first set of printing parameters, which, as will be explained in more detail below, be used to control the print head 2.1.

FIG. 3 shows a first printed image in the form of a franking imprint 4.1 according to the specifications of Deutsche Post AG, which was created with the printhead 2.1 on the letter 4. The franking impression 4.1 comprises different subregions 4.2 to 4.5 of different print image type. Thus, the first subarea 4.2 is a two-dimensional barcode and the second subarea 4.3 is a one-dimensional barcode, while the third and fourth subareas 4.4 and 4.5 are each an area with text and free graphics.

With regard to sharpness and contrast of the printed image 4.1, there are different requirements for the subregions of different types of printed image. Thus, the two-dimensional barcode 4.2 has high requirements for sharpness and contrast in the area of Edges of the rectangles or squares created over the pixels. This applies both in the direction of printing and across it. In contrast, these strict requirements in the one-dimensional barcode 4.3 usually only in one direction, usually the printing direction. In the case of the text or the free graphics of subsections 4.4 and 4.5, in turn, other requirements must be met. This is taken into account by the present invention in that the activation of the print head 2.1 takes place as a function of the print image type at the location of the respective pixel to be generated.

The following is with reference to the FIGS. 1 to 3 a preferred embodiment of the method according to the invention for operating a printer using a preferred embodiment of the method according to the invention for driving a print head described with the printer 2 from FIG. 1 is carried out.

First, the procedure is started in a step 6.1. In a joining step 6.2, the ink ribbon cassette 3 is inserted into the franking machine 1 in such a way that it is correctly assigned to the print head 2.1. Here, as described above, the first memory 3.4 is automatically connected via corresponding contact elements with the processing unit 1.4.

In a step 6.3, the processing unit 1.4 checks whether reading of the print parameters from the first memory should take place. This is the case, on the one hand, when the described insertion of a ribbon cassette 3 has been detected as a first event. Likewise, it is stipulated that the reading should take place each time the franking machine 1 is switched on. Turning on the franking machine 1 thus also represents an event triggering the reading of the printing parameters. It is understood that in other variants of the invention, other temporal or non-temporal events can be defined which trigger the reading of the printing parameters, as described in the beginning already described.

If the reading of the printing parameters is to take place, the processing unit 1.4 automatically reads the first printing parameter set from the first memory 3.4 in a reading step 6.4. The processing unit 1.4 stores the second memory 1.5 connected to the processing unit 1.4 in the form of a volatile main memory of the franking machine 1. It should be understood, however, that in other variants of the invention it may also be provided that the second memory is a non-volatile one Storage is. Incidentally, it may also be sufficient to read the printing parameters from the first memory only every time a ribbon cassette is detected.

In a step 6.5 it is checked whether a printing operation should be carried out, for example, a letter 4 is to be franked. If this is the case, the first print element of the print head 2.1 to be triggered in accordance with the print image 4.1 to be generated is first selected in a step 6.6.

In a determination step 6.7, the processing unit 1.4 then estimates, on access to the first set of pressure parameters stored in the second memory 1.5, the optimum first amount of energy with which the selected pressure element must be supplied in order to produce a high-quality franking imprint on the letter 4.

In order to enable a determination of the optimal first amount of energy adapted to the type of print image, the first set of print parameters has a separate subparameter set for each print image type to be expected. In the present case, this is thus a first partial parameter set for the print image type "two-dimensional barcode", a second partial parameter set for the print image type "one-dimensional barcode" and a third partial parameter set for the print image type "text and free graphics".

Depending on which print image type is assigned to the location of the currently considered first pixel of the first print image, the processing unit 1.4 accesses the partial parameter set of the first print parameter set assigned to this print image type in order to estimate the optimum first energy quantity. The estimation of the first amount of energy will be explained in more detail below.

It is understood here that in other variants of the invention it can also be provided that the determination of the optimal first amount of energy adapted to the print image type can also be achieved by different or additional to the use of the respective print image type associated partial parameter sets different determination algorithms for the optimal first amount of energy be used. Different print image types are then assigned different determination algorithms which the processing unit then uses as a function of the print image type of the current image point.

In a step 6.8, the processing unit then checks whether another printing element of the print head 2.1 is to be controlled. If this is the case, jump back to step 6.6, in which then the next to be controlled pressure element of the print head 2.1 is selected.

In this way, for each pixel of the first printed image 4.1 to be created, all the optimum first amounts of energy for the control of the printing elements are determined in advance. In other words, the drive sequences for the print head 2.1 are determined in advance.

In a step 6.9 comprising all feed steps for the print image 4.1 to be created, the processing unit 1.4 then controls the energy supply device 2.2 in such a way that in each case a corresponding first amount of energy is supplied to the individual printing elements. The determination of the amount of energy in advance for the entire print image has the advantage that a fast printing process can be achieved.

It is understood that in other variants of the invention it can also be provided that not only an optimal first amount of energy is determined using a partial parameter set corresponding to the current print image type of the first pressure parameter set. Rather, a separate optimum first amount of energy can be calculated for each partial parameter set. For the three different print image types of the first print image 4.1 (two-dimensional barcode, one-dimensional barcode, text / free graphics), therefore, three optimal first amounts of energy are calculated per pixel using the respective partial parameter set.

In this way, in the case of these variants, three different print image types assigned to the print image 4.1 are ultimately determined for the print head 2.1. In the step in which the energy supply to the individual printing elements then takes place, a selection of the corresponding control sequence, which is then taken from the actually used optimal first amount of energy for this pixel depending on the print image type of the current pixel in a selection step.

The printing is done column by column. In this case, all printing elements of the print head 2.1 to be triggered in accordance with the print image 4.1 to be generated are actuated to generate a print column in a drive sequence. To generate the next printing column, all printing elements of the print head 2.1 to be triggered according to the print image 4.1 to be generated are then in turn controlled in a further drive sequence.

If no further printing element is to be actuated, for example because all the columns of the printed image 4.1 have been printed or a cancellation has taken place, then in a step 6.10 it is finally checked whether the method sequence should be ended. If this is the case, the procedure ends in a step 6.11. Otherwise, jump back to step 6.3.

In the following, the example of a first pressure element 2.3 explains in more detail how the estimation of the first amount of energy E is carried out by the processing unit 1.4 in the determination step using the first pressure parameter set and a corresponding determination algorithm.

The amount of energy E _{p, a} to be supplied to the pressure element 2.3 depends, on the one hand, on the optimum temperature of the first pressure element 2.3 required for optimum melting of the color particles and, on the other hand, on the current temperature of the pressure element 2.3. The closer the actual temperature of the pressure element 2.3 is to the required optimum temperature of the first pressure element 2.3, the lower the actual amount of energy E _{p, a to be supplied} .

The current temperature of the pressure element 2.3 depends on the one hand on the current temperature in its environment, which is detected in the present case by a temperature sensor 2.6 in the print head 2.1. Furthermore, it depends on the relevant printed history of the printing element 2.3 and its two adjacent printing elements 2.4 and 2.5. If energy was supplied to the printing element 2.3 or one or both adjacent printing elements 2.4 and 2.5 in a preceding feeding step, a certain residual energy surplus is still stored in the printing element 2.3, which is expressed in an elevated temperature.

Since this residual energy surplus is degraded by heat transfer to the environment comparatively quickly, it is sufficient in the present example, only the control of the printing element 2.3 and its two adjacent printing elements 2.4 and 2.5 in the immediately preceding last drive sequence, ie the last printed pressure column, and the control of Pressure element 2.3 even in the penultimate Ansteuersequenz, ie the penultimate printed pressure column to take into account in order to obtain a sufficiently accurate estimate of the required amount of energy E _{p, a} .

It goes without saying, however, that in other variants of the invention an even more retrospective or a less extensive consideration of the printed history can be provided. This can in particular of the type of Printhead, especially the prevailing heat transfer conditions, depend.

wobei:

E_max

: Energie, die einem Druckelement zugeführt werden muss, wenn ihm während der letzten und vorletzten Ansteuersequenz und seinen unmittelbaren Nachbarn während der letzten Ansteuersequenz keine Energie zugeführt wurde;

ΔE_p,v :

Energieabschlag für eine Ansteuerung des Druckelements in der letzten Ansteuersequenz;

ΔE_p,vv :

Energieabschlag für eine Ansteuerung des Druckelements in der vorletzten Ansteuersequenz;

ΔE_pn,v :

Energieabschlag für eine Ansteuerung eines unmittelbar benachbarten Druckelements in der letzten Ansteuersequenz;

s_p,v

: Wahrheitswert der Ansteuerung des Druckelements in der letzten Ansteuersequenz;

s_p,vv

: Wahrheitswert der Ansteuerung des Druckelements in der vorletzten Ansteuersequenz;

s_pnl,v

: Wahrheitswert der Ansteuerung des unmittelbar links benachbarten Druckelements in der letzten Ansteuersequenz;

s_pnl,v

: Wahrheitswert der Ansteuerung des unmittelbar rechts benachbarten Druckelements in der letzten Ansteuersequenz.

In the determination step 6.7, the processing unit 1.4 estimates the amount of energy E _{p, a} currently to be supplied taking into account the print history of the printing element 2.3 and its two adjacent printing elements 2.4 and 2.5 according to the following equation: $$e_{p.a}=e_{\mathrm{Max}}-\left(s_{p.v}\cdot \Delta e_{p.v}\right)-\left(s_{pnl.v}\cdot \Delta e_{pn.v}\right)-\left(s_{pnr.v}\cdot \Delta e_{pn.v}\right)-\left(s_{p.vv}\cdot \Delta e_{p.vv}\right).$$

in which:

E _max

: Energy to be supplied to a printing element when it has not been energized during the last and penultimate driving sequence and its immediate neighbors during the last driving sequence;

ΔE _{p, v} :

Energy discount for a control of the printing element in the last drive sequence;

ΔE _{p, vv} :

Energy discount for a control of the printing element in the penultimate drive sequence;

ΔE _{pn, v} :

Energy discount for a control of an immediately adjacent printing element in the last drive sequence;

s _{p, v}

: Truth value of the drive of the print element in the last drive sequence;

s _{p, vv}

: Truth value of the driving of the printing element in the penultimate driving sequence;

s _{pnl, v}

: Truth value of the drive of the immediately left adjacent printing element in the last drive sequence;

s _{pnl, v}

: Truth value of the control of the immediately right adjacent pressure element in the last drive sequence.

The truth values in each case have the value "1" if the relevant activation actually took place, or the value "0" if the relevant activation did not take place. The truth values are logged by the processing unit 1.4 in the second memory 1.5. At each completion of a printing operation, they are set by the processing unit 1.4 to the value "0", if it is assumed that the time to the next printing process is so long that the residual energy surplus has been reduced by heat transfer to the environment. If this is not the case, this can be reset also be delayed in order to work with the optimal amount of energy even in a fast subsequent further printed image.

In each determination step 6.7, the relevant truth values for the printing elements to be considered are read from the second memory 1.5. In the present case, this results in 16 possible different previous constellations with different values for the amount of energy E _{p, a} currently to be supplied

$$\Delta E_{p,vv}=E_{pn,v}-E_{\min },$$

$$\Delta E_{pn,v}=\frac{E_{p,v}-E_{pn,v}}{2},$$

wobei:

E_max

: Energie, die einem Druckelement zugeführt werden muss, wenn ihm während der letzten und vorletzten Ansteuersequenz und seinen unmittelbaren Nachbarn während der letzten Ansteuersequenz keine Energie zugeführt wurde;

E_p,v

: Energie, die einem Druckelement zugeführt werden muss, wenn eine Ansteuerung des Druckelements in der letzten Ansteuersequenz erfolgte;

E_pn,v

: Energie, die einem Druckelement zugeführt werden muss, wenn eine Ansteuerung des Druckelements und seiner beiden Nachbarn in der letzten Ansteuersequenz erfolgte;

E_min

: Energie, die einem Druckelement zugeführt werden muss, wenn eine Ansteuerung des Druckelements und seiner beiden Nachbarn in der letzten Ansteuersequenz erfolgte und eine Ansteuerung des Druckelements in der vorletzten Ansteuersequenz erfolgte.

The energy discounts are calculated according to the following equations: $$\Delta e_{p.v}=e_{\mathrm{Max}}-e_{p.v}.$$

$$\Delta e_{p.vv}=e_{pn.v}-e_{\min }.$$

$$\Delta e_{pn.v}=\frac{e_{p.v}-e_{pn.\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="imgf0001.png"\; state="\{\{state\}\}">v</figure-callout>}}}{2}.$$

in which:

E _max

: Energy to be supplied to a printing element when it has not been energized during the last and penultimate driving sequence and its immediate neighbors during the last driving sequence;

_{Ep, v}

: Energy to be supplied to a printing element when driving of the printing element occurred in the last driving sequence;

E _{pn, v}

: Energy to be supplied to a printing element when driving of the printing element and its two neighbors occurred in the last driving sequence;

E _min

: Energy that must be supplied to a printing element, when a control of the printing element and its two neighbors in the last drive sequence was carried out and a control of the printing element in the penultimate drive sequence was carried out.

The energy values E _max , E _{p, v} , E _{pn, v} and E _min thus represent energy supply values for different energy supply constellations in preceding energy supply steps, from which the energy premiums for the respective print histories can be determined. Table 1: First partial parameter set 10 ° C 20 ° C 30 ° C 40 ° C 50 ° C 55 ° C E _max [μJ] 133 mm / s 294 277 247 202 159 110 150 mm / s 293 280 248 199 159 110 Ep _{, v} [μJ] 133 mm / s 179 168 160 136 109 80 150 mm / s 183 168 156 136 109 80 E _{pn, v} [μJ] 133 mm / s 135 120 104 104 81 60 150 mm / s 125 108 104 97 79 60 E _min [μJ] 133 mm / s 91 76 71 85 66 50 150 mm / s 87 68 67 75 62 50

The energy values E _max , E _{p, v} , E _{pn, v} and E _min represent pressure parameter values in the form of energy parameter values stored in the first pressure parameter set. In the present example, the print parameter set has a number of sub-parameter sets in which discrete energy values E _max , E _{p, v} , E _{pn, v} and E _min are stored for two different feed rates of the letter 4 and a number of different temperatures of the print head 2.1. Table 1 below shows an example of a first partial parameter set.

The energy values E _max , E _{p, v} , E _{pn, v} and E _{min of} the first partial parameter set are matched to the ink ribbon cassette 3 and the ink ribbon 3.1, in particular the color particles of the ink layer 3.2. Furthermore, they are tuned to a specific type of printed image to be generated, namely the generation of a two-dimensional barcode.

The first set of pressure parameters also comprises two further sub-parameter sets whose energy values E _max , E _{p, v} , E _{pn, v} and E _{min are} likewise respectively matched to the ink ribbon cassette 3 and the ink ribbon 3.1. This is a second subparameters set, which is further tuned to the generation of a one-dimensional barcode, and a third subparameters set, which is further tuned to the generation of text and free graphics.

The temperature of the print head 2.1 and the feed rate of the letter 4 each represent a prevailing in the region of the print head state parameters that flow into the determination of the currently supplied amount of energy E _{p, a} . The temperature of the print head 2.1 is detected by the temperature sensor 2.6 and forwarded to the processing unit 1.4. The feed rate of the letter 4 is detected by the sensor 1.6 and also passed on to the processing unit 1.4.

It goes without saying that other variants of the invention may additionally or alternatively also take into account other state parameters which have a corresponding influence on the printed result.

When determining the amount of energy E _{p, a} currently to be supplied, the processing unit 1.4 first of all selects the corresponding partial parameter set in accordance with the type of print image currently to be generated. On the basis of the values supplied by the temperature sensor 2.6 and the sensor 1.6, he then extracts the corresponding energy values E _max , E _{p, v} , E _{pn, v} and E _min from the selected partial parameter set.

In the event that the values of the temperature sensor 2.6 or of the sensor 1.6 are between the values of the selected partial parameter set, the processing unit 1.4 determines an intermediate value for the respective energy value E _max , E _{p, v} , E _{pn, v} and E _min by linear Interpolation.

It goes without saying, however, that in other variants of the invention, another way of determining such intermediate values may be provided. Likewise, a correspondingly fine subdivision of the stored energy values E _max , E _{p, v} , E _{pn, v} and E _{min can be} provided, so that the determination of such intermediate values for an estimate with sufficient accuracy is unnecessary.

If the correct energy values E _max , E _{p, v} , E _{pn, v} and E _min have been determined in this way, the processing unit still reads the truth values s _{p, v} , s _{p, vv} , s _{pnl, v} and _{p that} belong to the pressure element 2.3 s _pnl, from the second memory 1.5 and then calculates the equations (1) to (4) the pressure element 2.3 currently supplied amount of energy E _{p, a} . This is then used as described above to control the printing element 2.3.

The described use of energy parameter sets has the advantage that regardless of the structure of the print head 2.1, the processing unit 1.4 can quickly calculate the corresponding activation parameters on the basis of corresponding characteristics of the print head 2.1, which can also be stored in the second memory. Alternatively, the energy supply device 2.2 can also be designed for this conversion, so that the processing unit 1.4 only has to transmit the energy amount E _{p, a} currently to be supplied to the energy supply device 2.2.

The following is with reference to the FIGS. 1 . 3 and 4 an embodiment of a method for operating a printer described with the printer 2 from FIG. 1 can be carried out.

First, the procedure is started in a step 106.1. In a connecting step 106.2, the ink ribbon cassette 3 is inserted into the franking machine 1 in such a way that it is correctly assigned to the print head 2.1. Here, as described above, the first memory 3.4 is automatically connected via corresponding contact elements with the processing unit 1.4.

In a step 106.3, the processing unit 1.4 checks whether reading of the print parameters from the first memory is to take place. This is the case, on the one hand, when the described insertion of a ribbon cassette 3 has been detected as a first event. Likewise, it is stipulated that the reading should take place each time the franking machine 1 is switched on. Turning on the franking machine 1 thus also represents an event triggering the reading of the printing parameters. It is understood that in other variants of the invention, other temporal or non-temporal events can be defined which trigger the reading of the printing parameters, as described in the beginning already described.

If the reading of the printing parameters is to take place, the processing unit 1.4 automatically reads the first printing parameter set from the first memory 3.4 in a reading step 106.4. The processing unit 1.4 stores the second memory 1.5 connected to the processing unit 1.4 in the form of a volatile main memory of the franking machine 1. It should be understood, however, that in other variants of the invention it may also be provided that the second memory is a non-volatile one Memory is. Incidentally, it may also be sufficient to read the printing parameters from the first memory only every time a ribbon cassette is detected.

In a step 106.5, it is checked whether a printing process should be carried out, for example, a letter 4 should be franked. If this is the case, the first print element of the print head 2.1 to be triggered in accordance with the print image to be generated is first selected in a step 106.6.

In a determination step 106.7, the processing unit 1.4 then estimates, on access to the first set of pressure parameters stored in the second memory, the optimum first amount of energy with which the selected printing element must be supplied in order to produce a high-quality franking imprint on the letter 4. How the estimation of the first amount of energy takes place has already been described in detail above in connection with the exemplary embodiment FIG. 2 explained, so that only reference is made to the above statements.

In a feed step 106.8, the processing unit 1.4 then controls the power supply device 2.2 in such a way that a corresponding first amount of energy is supplied to the selected pressure element.

In other words, in the present example, immediately before the activation of each pressure element, a determination of the first amount of energy takes place. This has the advantage that the temperature of the print head 2.1 to be taken into account when determining the first amount of energy is included in the determination with greater accuracy. Furthermore, the actual print history and not just the preselected print history can be considered, i. The failure of individual or multiple actuators can be recorded and taken into account.

In a step 106.9, the processing unit then checks whether a further printing element of the print head 2.1 is to be controlled. If this is the case, the system jumps back to step 106.6, in which case the next print element of the print head 2.1 to be controlled is selected.

The printing is done column by column. In this case, to generate a print column in a drive sequence, all the print elements 2.1 of the print head 2.1 to be triggered in accordance with the print image to be generated are actuated. To generate the next printing column, all printing elements of the print head 2.1 to be triggered according to the print image to be generated are then in turn driven in a further drive sequence.

If no further printing element is to be controlled, for example because all the columns of the printed image have been printed or a cancellation has taken place, it is finally checked in a step 106.10 whether the method sequence should be ended. If this is the case, the procedure ends in a step 106.11. Otherwise, it jumps back to the step 106.3.

The present invention has been described above with reference to an example in which the amounts of energy for the entire print image are predefined ( FIG. 2 ) were determined. It is understood, however, that in other variants of the invention, another approach may be provided. For example, the determination of the amounts of energy can be carried out in advance for the respective printing gaps. The determination of the amounts of energy can in particular already take place while the drive sequence for the preceding pressure column is still running, so that no appreciable loss of time is associated with this.

The present invention has been described above solely by way of examples using energy parameter sets. It is understood, however, that in other variants of the invention it can also be provided that any parameters which can be used to determine the correct drive values for the printing elements can be used as printing parameters. For example, it may be directly to voltages and / or currents and / or pulse lengths, etc., which could be used directly to control the printing elements.

Furthermore, the present invention has been described above solely by means of an example with a franking machine. It is understood, however, that the invention can also be used for any other applications.

Claims (38)

1. Method for actuating a print head (2.1) which operates according to the thermal transfer principle and comprises a plurality of printing elements (2.3, 2.4, 2.5), in which method

   - in a first determination step (6.7) the first quantity of energy to be supplied to a first printing element (2.3) in a first supply step (6.9) is determined,

   - in a further determination step (6.7) the further quantity of energy to be supplied to an associated printing element (2.3, 2.4, 2.5) in a further supply step (6.9) is determined, and

   - in the first supply step (6.9) the first quantity of energy is supplied to the first printing element (2.3) in order to transfer ink from an ink carrier device (3) assigned to the print head (2.1) onto a substrate (4) assigned to the ink carrier device (3) to produce a first pixel of a printed image (4.1), and

   - in the further supply step (6.9) the further quantity of energy is supplied to the associated printing element (2.3, 2.4, 2.5) in order to transfer ink from the ink carrier device (3) onto the substrate (4) to produce a further pixel of the printed image (4.1),

   characterised in that

   - the printed image (4.1) comprises a first sub-region (4.2, 4.3, 4.4, 4.5) and a further sub-region (4.2, 4.3, 4.4, 4.5) of different printed image type,

   - the first pixel is assigned to the first sub-region (4.2, 4.3, 4.4, 4.5), and

   - the further pixel is assigned to the further sub-region (4.2, 4.3, 4.4, 4.5),

   - different requirements in terms of contrast and sharpness are defined for the different printed image types, and

   - the first quantity of energy is determined in the first determination step (6.7) as a function of the printed image type of the printed image (4.1) in the first sub-region (4.2, 4.3, 4.4, 4.5) and

   - the further quantity of energy is determined in the further determination step (6.7) as a function of the printed image type of the printed image (4.1) in the further sub-region (4.2, 4.3, 4.4, 4.5).
2. Method according to claim 1, characterised in that the first quantity of energy is determined in the determination step (6.7) using a first printing parameter set as a function of the printed image type at the location of the first pixel.
3. Method according to claim 2, characterised in that the first printing parameter set is an energy parameter set.
4. Method according to any one of the preceding claims, characterised in that

   - the first quantity of energy is determined in the determination step (6.7) using a first printing parameter set, wherein

   - the first printing parameter set comprises sub-parameter sets assigned to different printed image types, and

   - the first quantity of energy is determined at least using that sub-parameter set which is assigned to the printed image type at the location of the first pixel.
5. Method according to any one of the preceding claims, characterised in that

   - the first quantity of energy is determined in the determination step (6.7) using a determination algorithm, wherein

   - determination algorithms assigned to different printed image types are provided, and

   - the first quantity of energy is determined at least using that determination algorithm which is assigned to the printed image type at the location of the first pixel.
6. Method according to claim 4 or 5, characterised in that

   - in the determination step (6.7) a first quantity of energy for the first pixel is determined in each case for different printed image types, and

   - in a selection step following the determination step (6.7) there is selected for use in the supply step that first quantity of energy which is assigned to the printed image type at the location of the first pixel.
7. Method according to any one of the preceding claims, characterised in that

   - in a reading step (6.4) preceding the determination step (6.7) a first printing parameter set characteristic of the ink carrier device (3) is read from a first memory (3.4) assigned to the ink carrier device (3), and

   - the first quantity of energy is determined in the determination step (6.7) using at least the first printing parameter set.
8. Method according to claim 7, characterised in that the first printing parameter set is read in the reading step (6.4) from the first memory (3.4) which is arranged on the ink carrier device (3).
9. Method according to claim 7 or 8, characterised in that the first printing parameter set comprises at least a first sub-parameter set, wherein the first sub-parameter set comprises at least a first printing parameter as a function of at least a first state parameter prevailing in the region of the print head (2.1).
10. Method according to claim 9, characterised in that the first sub-parameter set comprises, for a plurality of discrete values of the first state parameter, in each case at least one associated first printing parameter value.
11. Method according to claim 10, characterised in that, in the determination step (6.7), intermediate values of the first printing parameter value are determined by interpolation for values of the first state parameter which lie between the discrete values of the first state parameter.
12. Method according to any one of claims 9 to 11, characterised in that the first state parameter is a temperature in the region of the print head (2.1) or a relative speed of a medium (4) relative to the printing element (2.3) and/or the ink carrier device (3).
13. Method according to any one of the preceding claims, characterised in that in the determination step (6.7) the energy supply to at least the first printing element (2.3) in at least one supply step preceding the first supply step (6.9) is taken into account.
14. Method according to claim 13, characterised in that in the determination step (6.7) the energy supply to at least a second printing element (2.4, 2.5) adjacent to the first printing element in at least one supply step preceding the first supply step (6.9) is taken into account.
15. Method according to claim 13 or 14, characterised in that the energy supply that has taken place in the last supply step before the first supply step (6.9) is taken into account.
16. Method according to any one of claims 13 to 15, characterised in that the energy supply that has taken place in the penultimate supply step before the first supply step (6.9) is taken into account.
17. Method according to any one of the preceding claims, characterised in that

    - the first quantity of energy is determined in the determination step (6.7) using a first printing parameter set, wherein

    - the first printing parameter set comprises a plurality of energy supply values for different energy supply constellations in at least one preceding supply step.
18. Method according to any one of the preceding claims, characterised in that in the determination step (6.7) the first quantity of energy is determined by subtracting from a predefined maximum quantity of energy to be supplied a deduction for the energy supply to at least the first printing element (2.3) that has taken place in at least one supply step preceding the first supply step (6.9).
19. Printer, comprising

    - a printing device which operates according to the thermal transfer principle and which comprises a print head (2.1) comprising a plurality of printing elements (2.3, 2.4, 2.5) and a processing unit (1.4) connected to the print head (2.1) for actuating the print head (2.1), and

    - an ink carrier device (3) assigned to the print head (2.1), wherein

    - the processing unit (1.4) is designed to determine the first quantity of energy to be supplied to a first printing element (2.3) and to trigger the supply of the first quantity of energy to the first printing element (2.3) in order to transfer ink from the ink carrier device (3) onto a substrate (4) assigned to the ink carrier device (3) to produce a first pixel of a printed image (4.1),

    - the processing unit (1.4) is designed to determine the further quantity of energy to be supplied to an associated printing element (2.3) and to trigger the supply of the further quantity of energy to the associated printing element (2.3) in order to transfer ink from the ink carrier device (3) onto the substrate (4) to produce a further pixel of the printed image (4.1),

    characterised in that

    - the printed image (4.1) comprises a first sub-region (4.2, 4.3, 4.4, 4.5) and a further sub-region (4.2, 4.3, 4.4, 4.5) of different printed image type,

    - the first pixel is assigned to the first sub-region (4.2, 4.3, 4.4, 4.5), and

    - the further pixel is assigned to the further sub-region (4.2, 4.3, 4.4, 4.5),

    - different requirements in terms of contrast and sharpness are defined for the different printed image types, and

    - the processing unit (1.4) is designed to determine the first quantity of energy as a function of the printed image type of the printed image (4.1) in the first sub-region (4.2, 4.3, 4.4, 4.5) and

    - the processing unit (1.4) is designed to determine the further quantity of energy as a function of the printed image type of the printed image (4.1) in the further sub-region (4.2, 4.3, 4.4, 4.5).
20. Printer according to claim 19, characterised in that the processing unit (1.4) is designed to determine the first quantity of energy using a first printing parameter set as a function of the printed image type at the location of the first pixel.
21. Printer according to claim 20, characterised in that the first printing parameter set is an energy parameter set.
22. Printer according to any one of claims 19 to 21, characterised in that

    - the processing unit (1.4) is designed to determine the first quantity of energy using a first printing parameter set, wherein

    - the first printing parameter set comprises sub-parameter sets assigned to different printed image types, and

    - the processing unit (1.4) is designed to determine the first quantity of energy at least using that sub-parameter set which is assigned to the printed image type at the location of the first pixel.
23. Printer according to one of claims 19 to 22, characterised in that

    - the processing unit (1.4) is designed to determine the first quantity of energy using at least one determination algorithm, wherein

    - determination algorithms assigned to different printed image types are provided, and

    - the processing unit (1.4) is designed to determine the first quantity of energy at least using that determination algorithm which is assigned to the printed image type at the location of the first pixel.
24. Printer according to claim 22 or 23, characterised in that

    - the processing unit (1.4) is designed to determine in each case a first quantity of energy for the first pixel for different printed image types, and

    - the processing unit (1.4) is designed to select for use in the supply step that first quantity of energy which is assigned to the printed image type at the location of the first pixel.
25. Printer according to any one of claims 19 to 24, characterised in that

    - a first memory (3.4) assigned to the ink carrier device (3) is provided, in which there is stored a first printing parameter set characteristic of the ink carrier device (3), and

    - the processing unit (1.4) is designed to read the first printing parameter set and to determine the first quantity of energy using at least the first printing parameter set.
26. Printer according to claim 25, characterised in that the first memory (3.4) is connected to the ink carrier device (3).
27. Printer according to claim 25 or 26, characterised in that the first printing parameter set comprises at least a first sub-parameter set, wherein the first sub-parameter set comprises at least a first printing parameter as a function of at least a first state parameter prevailing in the region of the print head (2.1).
28. Printer according to claim 27, characterised in that the first sub-parameter set comprises, for a plurality of discrete values of the first state parameter, at least one associated first printing parameter value.
29. Printer according to claim 28, characterised in that the processing unit (1.4) is designed to determine, by interpolation, intermediate values of the first printing parameter value for values of the first state parameter which lie between the discrete values of the first state parameter.
30. Printer according to any one of claims 27 to 29, characterised in that the first state parameter is a temperature in the region of the print head (2.1) or a relative speed of a medium (4) relative to the printing element (2.3) and/or the ink carrier device (3).
31. Printer according to any one of claims 19 to 30, characterised in that the processing unit (1.4) is designed to take into account the energy supply to at least the first printing element (2.3) that has taken place beforehand.
32. Printer according to claim 31, characterised in that the processing unit (1.4) is designed to take into account the energy supply to at least a second printing element (2.4, 2.5) adjacent to the first printing element (2.3) that has taken place beforehand.
33. Printer according to claim 31 or 32, characterised in that the processing unit (1.4) is designed to take into account the last energy supply that has taken place.
34. Printer according to any one of claims 31 to 33, characterised in that the processing unit (1.4) is designed to take into account the penultimate energy supply that has taken place.
35. Printer according to any one of claims 19 to 34, characterised in that

    - the processing unit (1.4) is designed to determine the first quantity of energy using a first printing parameter set, and

    - the first printing parameter set comprises a plurality of energy supply values for different energy supply constellations in at least one preceding energy supply.
36. Printer according to any one of claims 19 to 35, characterised in that the processing unit (1.4) is designed to determine the first quantity of energy in that it is designed to subtract from a predefined maximum quantity of energy to be supplied a deduction for at least one preceding energy supply to at least the first printing element (2.3).
37. Printer according to any one of claims 19 to 36, characterised in that it is designed as a printer unit of a franking machine (1).
38. Franking machine comprising a printer (2) according to any one of claims 19 to 37.

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