EP0578042A2 - Method for controlling the column-by-column printing of a postal stamp image in a franking machine - Google Patents

Abstract

In a method for controlling the column-by-column printing of a postage-stamp image (14) in a franking machine, the image information is stored in coded form and, before the particular printing operation, is converted into binary signals for the activation of printing elements (d1-d240). Invariable image information and variable image information are converted separately from one another, the converted variable and invariable image information being composed during the printing of the postage-stamp image (14). A visual time sequence of the printing during the franking of post is thereby achieved. <IMAGE>

Description

The invention relates to a method for controlling the column-wise printing of a postage stamp image in a postage meter machine, in which the image information is stored in coded form and converted into binary signals for actuating printing elements before the respective printing process.

In this known method, a postage stamp image in the form of coded image information is kept in a memory for each possible postage value. When the postage stamp image is printed on an envelope, it is passed under a print head, the printing elements of which are arranged in a column transverse to the transport movement. Depending on the weight of the letter or the size of the envelope, a postage stamp image with the appropriate postage value is selected and printed. Before or during column-by-column printing, the coded image information is decoded, converted into binary data and binary signals are generated from these for driving the printing elements. If there are many different postage values or if the postage stamp image is to contain further variable image parts, such as a date, a memory with a large storage capacity or a large number of electronic memory modules must be provided for storing the coded image information. This increases the space required in a franking machine, the technical effort and the costs.

A further disadvantage is that the conversion of the coded image information for an entire postage stamp image is relatively time-consuming. The time required for coding increases the time between two prints in a postage meter machine, so that the throughput of letters per unit of time is restricted.

A method is known from US Pat. No. 4,580,144 in which the postage stamp image is composed of two partial images. The constant portion of the image is printed on an envelope by a first printing station. The postage value, which can change depending on the letter, is printed by a second printing station. The image information for the variable image part is available in coded form and is converted into binary signals for driving printing elements of a thermal transfer printhead during the printing process. By dividing the postage stamp image to be printed into two partial prints, the printing speed for the overall stamp can be increased. Since two printheads are used in this known solution, the technical outlay is great.

A printing method is known from DE 40 34 292 A1, in which a fixedly predetermined part of the postage stamp image is stored in the franking machine in a memory, while another part is kept ready in a data processing system arranged away from the franking machine. From the data processing system, data of the fixedly specified part are transmitted to the franking machine and assembled there before printing. The data of the predetermined part of the postage stamp image are stored in a non-volatile memory.

Furthermore, from DE 37 12 100 A1 a franking machine message printing system is known, in which the franking machine has a memory for advertising messages. These advertising messages can be modified, print data being transmitted to the memory from a remote station.

Furthermore, from EP 0 352 498 A1 a franking machine with a first memory is known, which stores fixed data of a printed image that is repeated with each franking. Modifiable data are stored in a second memory. The data from the two memories are overlaid for printing.

It is an object of the invention to provide a method for controlling the column-wise printing of a postage stamp image in a franking machine, in which a large number of different postage stamp images can be generated with little technical effort and a high throughput of letters can be achieved.

This object is achieved for a method of the type mentioned above in that unchangeable image information and changeable image information are implemented separately from one another and in that the converted changeable and unchangeable image information is put together during the printing of the postage stamp image.

The invention is based on the consideration that when the unchangeable image information and the changeable image information are converted into binary signals separately, it is possible to split the conversion process and to carry out the sub-processes at different times. For example, the unchangeable picture information, the recurring picture parts of the postage stamp image are implemented in a period in which no printing takes place, for example during the transport of envelopes to the printing station. This saves time for the conversion during the printing process and this can be carried out more quickly. The throughput of letters in the franking machine is thus increased. By combining the converted image information only during printing, the time between the definition of the variable image information to be printed, which depends, for example, on the weight of a letter, and the actual printing is minimized. This also increases the throughput of letters in the franking machine. The invention therefore merges the changeable and unchangeable image information in an optimal time, so that the franking of mail is accelerated overall.

Due to the separate treatment of unchangeable and changeable image information, the binary data of which are only combined during the printing of a postage stamp image, a large number of different postage stamp images can be generated by providing different sets with immutable or changeable image information. Neither a large storage volume nor a complicated hardware technology is required for this. The method can therefore be implemented with little technical effort.

In a preferred exemplary embodiment of the invention, the variable image information for each printing column is implemented separately between the printing of two printing columns, for example during the transport of the letter in the printing station for printing the postage stamp image. This changeable image information As is known, relate to the variable image portions of the postage stamp image, for example the postage value or a date. Since the amount of variable image information is generally smaller in relation to the unchangeable image information, it takes only a short time to convert the variable image information. This shortens the time required for converting coded image information into binary signals, which has a direct effect on the throughput of envelopes per unit of time. This further improves the throughput of the franking machine.

Another preferred embodiment provides that the variable image information is converted into binary data and stored in a memory prior to printing the postage stamp image, and that the binary signals are generated from the binary data. In this embodiment, the conversion process takes place before printing, i.e. the printing process can be carried out in an even shorter time, since no time has to be provided for the conversion during printing. This increases the throughput of the franking machine even further.

According to a further exemplary embodiment of the invention, the unchangeable coded image information is kept ready in a read-only memory. This image information is read from this ONLY read memory and decoded before the start of printing. The read only memory generally contains the control program for the microprocessor, under whose control the method according to the invention is carried out. The NUR read-only memory is generally arranged on a chip module and is replaced when the franking machine's work program is changed. With this The unchangeable image information for predetermined image portions of a postage stamp image can also be exchanged in a simple manner. Furthermore, since the coded, unchangeable image information can be taken directly from the read-only memory, intermediate storage of this image information is not necessary. This can save storage space or electronic components.

In a further embodiment of the invention, the unchangeable image information is converted into binary data from which binary signals are generated before a postage stamp image is printed. This ensures that when a postage stamp image is printed, data that has already been decoded can be accessed with respect to the constant image part. The time required for data conversion during printing can thus be saved. This improves the flexibility of the franking machine and further increases the throughput of envelopes per unit of time.

In another embodiment, the coded image information is provided with control characters which indicate whether the image information is variable or unchangeable. On the basis of these control characters, the type of image information that is usually stored in a memory can be recognized and the image information can be treated differently when read out. With the aid of the control characters, the image information can also be stored or buffered, depending on its type, in various memories or memory areas. The control characters can be attached to any image information, for example in the form of a control bit. The respective binary value then identifies the type of image information.

In a preferred embodiment, the control characters have a value that is not contained in the character set of the coded image information. As a result, the control character, for example a binary word with an 8-bit word length, can be arranged in the middle of a sequence of coded image information and can be recognized as control characters during analysis in the course of converting the image information into binary data.

A practical embodiment of the method according to the invention is characterized in that the unchangeable image information is converted column-wise sequentially in an address-oriented manner into binary data and examined for control characters, each address being assigned to a printing element such that when a predetermined window control character occurs, the associated address is temporarily stored as a window address becomes that before the printing of a line, the binary data of the unchangeable image information are provided sequentially in an address-oriented manner for printing for the printing elements in question, that when the printing program is executed and the window address is reached, a branch is made to a window program in which the changing image information is converted into binary data and are provided in an address-oriented manner for the printing elements in question, and that after the window program has been processed, the program branches back to the printing program .

In this embodiment of the invention, a minimal storage space is required for storing the coded image information and the binary data, the number of work steps being small and the required program parts having a simple, manageable structure.

In another embodiment, several window programs are kept ready, the respective start address of which is stored indirectly under the window address depending on the control character. Although this increases the memory requirement for a read-only memory in which the window programs are stored, it is possible to branch quickly to these window programs, the processing time of which influences the throughput of letters in the franking machine, without program parameters having to be determined and transferred to these window programs.

Furthermore, in one exemplary embodiment of the invention, a large number of sets of coded variable image information can be provided, which are assigned to different information of a control signal. This makes it possible to provide a set with variable image information depending on the information contained in the control signal. As information, the control signal can contain a postage value to be printed, a date, a time, a serial number of the franking machine, a running print number and / or a variable image part of a company cliché.

Furthermore, in an advantageous development of the invention, a plurality of sets of coded, unchangeable image information are kept available, which are optionally accessed. This makes it possible to readjust or change the recurring fixed parts of the postage stamp image if necessary. For example, the company cliché in the postage stamp image can be modified in this way.

In a preferred embodiment of the invention, run length coding is used to code the image information. This type of coding is characterized by high data compression, so that storage space can be saved. In addition, the decoding of the image information and the generation of binary data can be carried out with little expenditure of time and a few process steps. As a result, the conversion time required for decoding is short.

Figur 1

ein unter einem Druckkopf transportiertes Briefkuvert, das mit einem Postwertzeichenbild bedruckt wird,

Figur 2

ein Blockschaltbild eines Hardwareaufbaus einer Frankiermaschine, der zum Durchführen des Verfahrens nach der Erfindung verwendet wird,

Figur 3

schematisch die Umwandlung der unveränderlichen und veränderlichen Bildinformationen in Binärdaten,

Figur 4

ein Flußdiagramm eines Programms zum Umwandeln der unveränderlichen Bildinformationen in Binärdaten und zum Erzeugen des Zugriffs auf die veränderlichen Bildinformationen, und

Figur 5

ein Flußdiagramm eines Programms zum Erzeugen von Binärdaten aus den veränderlichen Bildinformationen während des Druckens.

An embodiment of the invention is explained below with reference to the drawings. It shows:

Figure 1

a letter envelope carried under a print head and printed with a postage stamp image,

Figure 2

2 shows a block diagram of a hardware structure of a postage meter machine which is used to carry out the method according to the invention,

Figure 3

schematically the conversion of the unchangeable and changeable image information into binary data,

Figure 4

a flowchart of a program for converting the unchangeable image information into binary data and for generating access to the changeable image information, and

Figure 5

a flowchart of a program for generating binary data from the variable image information during printing.

In FIG. 1, a letter envelope 10 is transported in a franking machine under a thermal transfer print head 12 in the direction of arrow 13 at a constant speed v and printed with a postage stamp image 14. The thermal transfer print head 12 has a thermal bar 16 with 240 printing elements d1 to d240 arranged next to one another. Each of these printing elements d1 to d240 has a heating resistor, which can heat the respective printing element d1 to d240 to a temperature at which the color of a thermal ink ribbon (not shown) passed under the thermal bar 16 melts and is thereby transferred to the envelope 10. In this way, the envelope is printed in columns like a grid during a transport movement. The columns s1, s2, s3, sj to sn are each printed approximately simultaneously by the printing elements d1 to d240, so that the printed image of a column, e.g. column sj, is straight. It should be noted here that the present invention can of course also be used for other printing processes, for example the ETR printing process (Electroresistive Thermal Transfer Ribbon).

The postage stamp image 14 has fixed, recurring image parts, such as a frame 18, a text 20, and a picture element 22. Further fixed picture parts can be, for example, company clichés, addresses and advertising information, which are not shown in FIG. 1 for reasons of clarity . Furthermore, the postage stamp image 14 contains variable image components in windows FE1, FE2, FE3. The window FE1 contains the current postage value, which is determined by the franking machine depending on the weight of the letter or its size. The window contains FE2 or FE3 franking machine-specific data that are changed depending on the franking machine operation.

FIG. 2 shows a block diagram of the hardware structure that can be used to carry out the method according to the invention. To control the course of the method, a microprocessor 24 is provided which accesses memory elements R1, R2, 26a to 26f, which will be described later. The microprocessor 24 communicates with peripheral modules, e.g. an electronic balance 28, which determines the weight of the envelope 10 to be printed with its content. Depending on this weight, the microprocessor 24 determines the postage value to be printed. Time data is transmitted to the microprocessor 24 via a clock module 25. An input keyboard 30 is used to manually control the operation of the franking machine.

A transport motor 32 is actuated via the input / output module and moves the envelope 10 under the print bar 16 of the thermal transfer print head 12. A coding module 33 detects the movement of the motor, as a result of which the exact position of the envelope 10 in the franking machine can be determined. A display 34 shows current operating states of the franking machine. This display 34 is also used to display the unchangeable and changeable image information, for example during editing. The input / output module also outputs binary data to a register 36 with a capacity of at least 50 bits, which are converted by a driver 38 into binary signals with which the printing elements d1 to d50 of the thermal transfer print head 12 are driven to print a column will.

The microprocessor 24 processes data stored in memory elements R1, R2, 26a to 26f. Two registers R1, R2 are volatile memories (RAM) and serve as working registers. A volatile pixel or pixel memory 26a contains in binary form in a column-wise arrangement corresponding to the printing, pixel data (binary data) from which the binary signals for controlling the printing elements d1 to d50 are generated directly. Each pixel in the pixel memory 26a can be addressed individually.

Data is temporarily stored in a volatile memory 26b serving as working memory for the microprocessor 24. The microprocessor 24 accesses a further memory 26c, which also serves as a working memory. This memory 26c is a non-volatile read / write memory. It can be designed as a battery-buffered memory or as an EEPROM. Changing image information, e.g. that of the windows FE1, FE2 and FE3, as well as image information which cannot be changed in an area S1.

Alphanumeric characters are stored in a character memory 26d as pixel data (pixels) in the form of binary data. The character memory 26d is designed as a read-only memory (ROM).

A program memory 26e, which is also in the form of a read-only memory (ROM), stores the program parts, during the execution of which the method according to the invention is executed. In one embodiment variant, the program memory 26e additionally contains the unchangeable image information for predetermined fixed image components, which are stored under the names assigned to them.

Furthermore, a booking memory 26f is provided, in which security-relevant data of the franking machine are stored, for example the sum of the used postage. The booking memory 26f is designed as a battery-buffered read / write memory.

For the sake of simplicity, FIG. 3 schematically shows the sequence of the method according to the invention for converting the coded image information into binary data for a column having only 50 pixels. In this embodiment, the printing elements d1 to d50 of the thermal bar 16 of the thermal transfer printing head 12 shown in the image part a) are arranged in a row.

A print pattern 40 of the column to be printed is indicated below the thermal transfer print head 12 in the image part b) of FIG. 3. The printing pattern consists of a distribution of colored printing dots, for example printing point 42, and unprinted printing dots, for example printing point 44. The printing dots are each printed by a printing element, e.g. the pressure point 42 through the pressure element d1. Each pressure point is a specifically addressable binary information, i.e. one bit assigned in the pixel memory 26a. The bits of a column can be addressed using a run variable A with the value range 1 to 50. The value of the run variable A is interpreted as the address for the printing elements d1 to d50.

It is assumed by way of example that the first four and the last 40 pressure points of the column are assigned to a recurring printing pattern which is designated by U. It is also believed that the fifth to the tenth pressure point (associated bits with run variable A = 5 to A = 10) form the variable print pattern of the window FE1.

The image part c) of FIG. 3 shows how the coded image information of the recurring print pattern U is converted into binary data and the occurrence of a window area is recognized. After editing, the unchangeable image information of the print pattern U is present in run-length-coded form as hexadecimal values in the working memory 26c. The coded image information is stored in bytes in a sequence with addresses a1 to a5 in area S1 for the column. The run length coding alternately specifies how many print dots are to be printed in color or non-color in succession. The entry "02" encoded in hexadecimal under address a1 means that the first two print points with addresses A = 1 and A = 2 (ie the run variable A has the value A = 1 or A = 2) should be printed in color. The run length X of the code "02" is therefore two. When the coded image information "O2" is converted, two bits with addresses A = 1, A = 2 are generated which have the value 1, so that the printing elements d1 and d2 assigned to the bits with addresses A = 1 and A = 2 are colored Generate pressure points. The same applies to the unchangeable image information loaded under address a2, with the difference that because of the alternating run length coding, the subsequent bits with addresses A = 3, A = 4 each contain the other binary value, ie 0. This means that no ink is transferred at the third and fourth pressure point, ie the printing elements d3 and d4 are not heated. A hexadecimal value "00" serves as a print control character for controlling the color change, ie it causes the switching of the printing element to non-heating and vice versa, where the run length X is zero. With the help of this print control character it is possible to form chains of pressure points of the same color information of any length. As a result, thermal print bars can be used with a number of print elements that is larger than the available value range of a byte.

As a result of the unchangeable image information, the hexadecimal value "51" appears at address a3. This value lies outside the defined value range of the run length coding, which for 50 printing elements ranges from hexadecimal "O1" to "32". Within the possible hexadecimal value range of a byte, which is known to range from "00" to "FF", values that occur outside the value range of the run length coding are interpreted as control characters. The first value "5" of the hexadecimal value "51" means that a window begins within which variable image information is to be provided. The second value "1" indicates the number of the window, i.e. on the window FE1. In this way, several windows can be marked. The method steps carried out when a control character occurs are explained later.

The value "28" occurring in the sequence of the unchangeable image information at the address a4 is interpreted so that the binary positions of the bits with the running variable A = 11 to A = 50 each have the value 1, i.e. the printing elements d11 to d50 transfer color to the envelope 10.

The value "F0" occurs at address a5, which in turn is interpreted as a control character. He has the Meaning that the end of the column has been reached. The run variable A is then to be reset to the initial value A1, and the conversion of the unchangeable image information into binary data for the next column can begin.

The lower image section d) of FIG. 3 schematically shows the conversion of the coded variable image information with the addresses b1 to b4 of the window FE1 into binary data. The variable image information is also encoded after the alternate run length coding and is converted in the manner described above. It should be noted that the value of the run variable A follows the value before the control character appeared.

FIG. 4 shows in a flowchart the program for generating binary data from the unchangeable image information and filtering out the control characters which indicate windows. This program is preferably carried out before switching on the printing operation, for example after a new postage stamp image has been defined or the existing postage stamp image has been modified. To change the postage stamp image, an editing program (not shown) is processed in which unchangeable and changeable image information is stored in the working memory 26c. After the start of the program in method step 50, the unchangeable image information belonging to a desired postage stamp image, which is stored, for example, in the working memory 26c, is selected and read out. After loading the coded data using the registers R1, R2 in method step 54, these print data are checked for control characters. If the control character with the meaning "end of image" occurs (process step 56), the program is ended in step 58. Otherwise, it is checked in method step 60 whether the control character with the meaning "end of column" has occurred. If this is the case, the process branches to step 62, the run variable A is reset to its initial value A = 1 and branches back to method step 54, and the system switches to the next column.

If the result in test step 60 is negative, it is checked in subsequent step 64 whether there is a control character which indicates a window in which variable image information is to be provided. If the answer is no, the coded print date examined is unchangeable image information and the method branches to step 66. There, the run length-coded data is decoded and the binary data is generated in accordance with the explanations for FIG. 3. In accordance with the run length X, the value A of the run variable is increased and then branched to step 54.

When the control character "window" occurs, step 68 is continued, in which the current value A 'of the run variable A is stored in the intermediate memory 26b. As mentioned, the control character contains a window number n as information, which is also stored. Since the length L, ie the number of pressure points or bytes, of the respective window is known in advance, the run variable A is increased by this amount and branched back to step 54. After all coded print data of the unchangeable image information have been analyzed and decoded, the program is exited at step 58. The binary data obtained during the decoding are stored in the pixel memory 26a.

In FIG. 5, the process steps that are carried out during printing are shown in a further flow chart. After the start of the program in step 70, the control signal coming from the electronic scale 28 is analyzed (method step 72) and the postage value to be printed is determined. Depending on this postage value, in method step 74, data in the working memory 26c with variable image information is accessed, which is assigned to this postage value. This data is provided as window print data for the window FE1 (method step 74). Access is by indexed addressing, as will be explained later in step 94.

In the subsequent step 76, a run variable C is loaded, which is interpreted as an address under which the binary data of the unchangeable image information are stored in the pixel memory 26a. This run variable C is in a fixed relationship to the run variable A mentioned above, which, as mentioned, is interpreted as the address for the binary data of a column. In method step 78, it is checked using the run variable C whether the postage stamp image has been printed. If this is the case, the printing program is ended in method step 80. Otherwise, it is checked in method step 82 whether an end of the column has been reached. If so, then all 50 binary information (bits) for printing a column is provided in register 36 (Figure 2) and that column can be printed in a single print. Then, in process step 86, the run variable C is set to the beginning of the next column.

If the answer is negative in step 82, the method branches to step 88. Here the value of the run variable A is determined from the current value of the run variable C. and in the subsequent step 90 checks whether the value A corresponds to the value A ', which was previously determined for this column in the program according to FIG. 4 (method step 68). If this is not the case, then binary data of an unchangeable image information are available. This binary data is loaded into the register 36 in step 92 and the run variable C is increased by 1. The method then branches back to method step 76.

If it is determined in step 90 that the current value of the run variable A corresponds to the value A ', the coded window print data provided in the work memory 26c in step 74 are decoded, converted into binary data by means of the run variable A in the address 36 in the address-oriented manner loaded and output at "column end" in step 84 to the thermal transfer print head 12. In step 94, the run variable C is also increased by the length L of the window FE1. Furthermore, an index variable I is increased by 1. This serves the purpose that when converting the coded window print data in the following column, the print data can be accessed by indexed addressing. The program then branches to step 76. If all print columns of the postage stamp image have been printed, the print program is exited at "end of image" (step 78).

In the present example, only coded print data were provided for a window FE1 and converted into binary data. Of course, further sets of print data for further windows, for example windows FE2 and FE3 (FIG. 1), can be provided in an analogous manner. In these or similar windows, the current date, the time, an ongoing Print number or a variable part of a corporate cliché can be printed.

In a variant of the previous exemplary embodiment of the invention, the unchangeable binary data, which are generated from the unchangeable runtime-coded image information by decoding, are temporarily stored in a first area of the pixel memory 26a. The changeable binary data obtained from the changeable image information are temporarily stored in a second area of the pixel memory 26a. When printing a column, the unchangeable and changeable binary data are read out from the first and second areas of the pixel memory 26a in the order specified by the control characters and written into the register 36 for printing a column. In this variant, the unchangeable and changeable image information is combined in register 36.

In another variant, the pixel memory 26a is divided into a plurality of memory areas, in accordance with the unchangeable and changeable image components. The division is made using the control characters. The variable image information can be stored in a memory area of the pixel memory 26a with fixed predetermined addresses corresponding to the pixels of the print image to be printed in columns. When changing the binary data of a window, the memory area is accessed via these fixed addresses and its data changed.

In a third variant, the unchangeable image information can be stored in a read-only memory, for example in the program memory 26e. When decoding the unchangeable picture information is on this Read-only memory 26e accessed. The intermediate storage of the run-length-coded, unchangeable image information can then be omitted. The corresponding memory area S1 of the working memory 26c can then be dispensed with.

Claims (18)

Method for controlling the column-wise printing of a postage stamp image (14) in a postage meter machine, in which the image information is provided in coded form and converted into binary signals for actuating printing elements (d1-d240) before the respective printing process, characterized in that unchangeable image information and changeable image information are separated are converted from one another and that the converted variable and unchangeable image information is put together during the printing of the postage stamp image (14). Method according to Claim 1, characterized in that the variable image information for each printing column (s1, s2, sj, sn) is implemented separately between the printing of two printing columns (eg sj, sj + 1). Method according to Claim 1, characterized in that the variable image information is converted into binary data and printed in a memory (26b) before the postage stamp image (14) is printed, and in that the binary signals are generated from the binary data. Method according to one of the preceding claims 1 to 3, characterized in that the unchangeable and changeable coded image information in separate areas of one non-volatile memory (26c) are available. Method according to Claim 1, characterized in that the unchangeable coded image information is kept ready in a ONLY read-only memory (26e) and is read out and decoded from it before the start of printing. Method according to one of Claims 1 to 5, characterized in that the unchangeable image information is converted into binary data from which binary signals are generated before a postage stamp image (14) is printed. Method according to one of the preceding claims, characterized in that the coded image information is provided with control characters (for example "51") which indicate whether the subsequent coded image information is variable or unchangeable. Method according to one of the preceding claims, characterized in that the image information is divided into the variable and unchangeable image information depending on the control characters. Method according to Claim 8, characterized in that the control characters have a value (for example "51") which is not contained in the character set of the coded image information. A method according to claim 9, characterized in that the unchangeable image information in a sequence (eg source addresses a1 to a5) are arranged in accordance with the column-wise printing, and control characters ("51") are inserted between the image information. Method according to claim 10, characterized in that the unchangeable image information is converted column-wise sequentially in an address-oriented manner into binary data and examined for control characters, each address (A) being assigned to a printing element, that when a control character (method step 64) occurs, the associated address as a window address ( A ') is temporarily stored in such a way that the binary data of the unchangeable image information are provided sequentially in an address-oriented manner for printing for the relevant printing elements (d1 to d256) in a print program, so that when the print program is executed and the window address (A') is reached a window program (method step 94) is branched, in which the variable image information is converted into binary data and is provided in an address-oriented manner for the printing elements in question, and that after the window program (94) has been processed, it leads to the printing program is branched back. Method according to Claim 11, characterized in that several window programs are kept ready, the respective start address of which is stored indirectly under the window address depending on the control character. Method according to one of the preceding claims, characterized in that a plurality of Sets of coded variable image information are provided, which are assigned to different information of a control signal. A method according to claim 13, characterized in that the control signal contains as information a postage value to be printed, a date, a time, a serial number of the franking machine, a running print number and / or a variable image part of a company cliché. Method according to claim 13 or 14, characterized in that the variable image information is accessed by indirect memory addressing. Method according to one of the preceding claims, characterized in that when sequential printing of a plurality of columns with increasing numbering, access to the variable image information takes place by means of indirect indexed memory addressing, the variable image information being converted into binary data in accordance with the number of the column to be printed. Method according to one of the preceding claims, characterized in that several sets of coded, unchangeable image information are kept available, which are optionally accessed. Method according to one of the preceding claims, characterized in that the run length coding is used for coding the image information.

Images