Method for controlling or regulating a folder of a printing press

A method and apparatus for controlling or regulating a folder of a printing press is disclosed. Setpoint fold values are generated on the basis of prepress stage data and printed copies are measured in the folded and/or partially folded state in order to determine actual fold values. The actual fold values which are determined in the process are compared with the corresponding setpoint fold values and, as a function of this comparison, the folder is set automatically in such a way that the actual fold values correspond to or are approximated to the setpoint fold values in subsequent printed copies.

This application claims the priority of German Patent Document No. 10 2005 013 361.4, filed Mar. 23, 2005, the disclosure of which is incorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method for controlling or regulating a folder of a printing press. Furthermore, the invention relates to a printing press having a folder.

Folders of printing presses serve to form folds on printed printing materials, a web-shaped printing material customarily being guided first of all through what is known as a folding former for fold formation according to the prior art, in order for a longitudinal fold to be formed in this way on the web-shaped printing material which has not yet been severed. Starting from the folding former, the web-shaped printing material is transported via several pull rolls in the direction of a cutting knife cylinder and a folding blade cylinder which interacts with the cutting knife cylinder, copies which are moved in the direction of a folding jaw cylinder with the aid of a folding blade cylinder being severed from the web-shaped printing material on the cutting knife cylinder. The copies which are severed from the web-shaped printing material on the cutting knife cylinder and are moved in the direction of the folding jaw cylinder by the folding blade cylinder are transferred to the folding jaw cylinder with formation of a first crossfold by the folding blade cylinder. Further, second crossfolds can be formed between the folding jaw cylinder and a gripper cylinder which interacts with the latter. The copies which have been provided in this way with a longitudinal fold and crossfolds can then be provided with second longitudinal folds while still in the region of a folding table which is connected behind the gripper cylinder, the second longitudinal folds running parallel to the longitudinal fold which was formed in the folding former.

If the fold formation is to be checked according to the prior art, a folded printed copy is removed from a printing press, unfolded and examined in the unfolded state by a printer. If the printer notices here that folds run obliquely, actuators for the folding former and/or the folding blade cylinder and/or the folding jaw cylinder and/or the folding table are adjusted manually by the printer in such a way that the desired fold is formed on subsequent printed copies. Here, the procedure is purely empirical according to the prior art, with the result that there are no reproducible results during the adjustment of the folder which is performed by the printer.

Proceeding from this, the present invention is based on the problem of providing a novel method for controlling or regulating a folder, and also of providing a printing press with a folder.

According to the invention, setpoint fold values are generated on the basis of prepress stage data, printed copies being measured in the folded and/or partially folded state in order to determine actual fold values, the actual fold values which are determined in the process being compared with the corresponding setpoint fold values, and, as a function of this comparison, the folder being set automatically in such a way that the actual fold values correspond to or are approximated to the setpoint fold values in subsequent printed copies.

In the context of the present invention, it is provided for the first time to regulate or control a folder on the basis of setpoint fold values which are generated from prepress stage data. For this purpose, printed copies are measured in the folded and/or partially folded state in order to determine actual fold values, the actual fold values which are determined in the process being compared with the setpoint fold values which are based on the prepress stage.

As a function of this comparison, actuating signals are determined for the actuators of the folder, in order to set the folder automatically in this way. As a result, it is possible to achieve reproducible results during the setting of folders. Furthermore, the method according to the invention can run fully automatically, with the result that an intervention by a printer is unnecessary.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following text, the present invention will be described in greater detail with reference toFIG. 1.

The principle method of operation of folders is known in principle to one skilled in the art addressed here and therefore does not require a detailed explanation. At this point, it is to be pointed out for the sake of completeness that a folder10for a printing press usually comprises a folding former11, a cutting knife cylinder12, a folding blade cylinder13, a folding jaw cylinder14and a gripper cylinder15. A printing material16is moved or guided through the folder10. What is known as a first longitudinal fold is produced in the region of the folding former11and what is known as a first crossfold is produced in the region between the folding blade cylinder13and the folding jaw cylinder14. In the exemplary embodiment shown, second crossfolds are produced between the folding jaw cylinder14and the gripper cylinder15. A folding table (not shown) can be arranged after the gripper cylinder15in order to produce second longitudinal folds which run parallel to the longitudinal fold which was produced in the folding former11.

The cutting knife cylinder12comprises at least one cutting knife17. Copies18can be severed with the aid of the cutting knives17from the printing material16which has been prefolded with a longitudinal fold in the region of the folding former11. The folding blade cylinder13comprises folding blades19and perforating needles20or grippers. The folding jaw cylinder14has folding jaws21,22and the gripper cylinder15has grippers23and folding blades24.

In order to provide a first crossfold, the cutting knife cylinder12, the folding blade cylinder13and the folding jaw cylinder14interact in such a way that, when a copy18is severed from the printing material16with the aid of a cutting knife17of the cutting knife cylinder12, the severed copy18is held at the start of the sheet by a perforating needle20or a gripper and is moved further by rotation of the folding knife cylinder13. As a result, the severed copy18is moved into a relative position between the folding blade cylinder13and the folding jaw cylinder14, which relative position is defined for the formation of the first crossfold, a folding blade19of the folding blade cylinder13pressing the copy18between opened first folding jaws21of the folding jaw cylinder14when this relative position is reached, whereas the perforating needle20or the gripper releases the copy18. The copy18′ which has thus been provided with the first crossfold and is held by the folding jaw cylinder14is then moved further in the direction of the gripper cylinder15by rotation of the folding jaw cylinder14.

In the exemplary embodiment ofFIG. 1, at least one second crossfold is formed between the folding jaw cylinder14and the gripper cylinder15. This takes place in that a copy18′ which is provided with a first crossfold is moved into a defined relative position between the folding jaw cylinder14and the gripper cylinder15, the first folding jaw21of the folding jaw cylinder14being opened in this relative position, a gripper23of the gripper cylinder15gripping that section of the copy18′ which is released by the first folding jaw21, and a folding blade24of the gripper cylinder15pressing the copy18′ between an opened second folding jaw22of the folding jaw cylinder14. The copy18″ which is provided thus with first and second crossfolds is subsequently released from the folding jaw cylinder14and fed to a further processing step, for example the formation of second longitudinal folds in the region of the folding table (not shown).

In the context of the present invention, it is provided to regulate a folder10of a printing press by the fact that setpoint fold values25are generated on the basis of prepress stage data, that printed copies are measured in the folded and/or partially folded state in order to determine actual fold values26, that the actual fold values26are compared with the setpoint fold values25in order to determine fold deviations27, and that, as a function of this comparison or of the fold deviations27, manipulated variables28,29,30and31are determined for the folder10, in order to set the folder10automatically in such a way that the actual fold values26correspond to or are approximated to the setpoint fold values25in subsequent printed copies.

The manipulated variables which are determined on the basis of the fold deviations27are manipulated variables28for the folding former11and/or manipulated variables29for the folding blade cylinder13and/or manipulated variables30for the folding jaw cylinder14and/or manipulated variables31for the gripper cylinder15. Furthermore, manipulated variables (not shown) can be generated for a folding table which is connected behind the gripper cylinder15. The manipulated variables28for the folding former11usually influence turner bars in a folder superstructure.

As has already been mentioned, it lies within the context of the present invention to generate the setpoint fold values25on the basis of prepress stage data. According toFIG. 1, this takes place in a setpoint generating device32which is supplied with digital prepress stage data, with the result that the setpoint generating device32can generate setpoint fold values25which are dependent on the printed image or subject on the basis of the prepress stage data. On the basis of the subject-based prepress stage data, setpoint spacings of setpoint folds which are to be performed in the folder10or setpoint fold lines with respect to a printed image or with respect to selected regions of a printed image are generated, with consideration of the longitudinal folds and/or crossfolds which are to be performed in the folder10as setpoint fold values25. During the determination of the actual fold values26, actual spacings of the actually performed actual folds or actual fold lines with respect to the printed image or with respect to the selected regions of the printed image are then determined on the folded or partially folded printed copy. This measuring of the printed copies in the folded and/or partially folded state takes place with the aid of at least one measuring device33.

In order to determine the fold deviations27, the actual spacings which are determined by measuring between the actually performed actual folds and the printed image and the generated setpoint spacings between the setpoint folds which are to be performed and the printed image are compared with one another, the fold deviations27being supplied to a regulating device34which then generates the manipulated variables28to31for the folder10on the basis of the fold deviations27.

In the context of the present invention, the actual fold values can be determined within the folder10in an online manner with respect to the folding process. Thus, for example, a measuring device can be integrated into the folder10in an adjoining manner to the folding former11, in order to measure the longitudinal fold which is produced in the region of the folding former11and to generate a corresponding actual fold value. Further measuring devices can likewise be integrated into the folder10, in order to generate, for example, corresponding setpoint fold values for first crossfolds which are produced between the folding blade cylinder13and the folding jaw cylinder14and for second crossfolds which are produced between the folding jaw cylinder14and the gripper cylinder15. A measuring device can likewise be integrated into the folding table (not shown), in order to measure the second longitudinal folds which are produced in the region of the folding table. In this case, the correspondingly folded or partially folded printed copy would accordingly be measured immediately after a fold has been performed, in order to provide a corresponding actual fold value for the previously performed fold. All the actual fold values are then determined online and automatically in the folder10and compared automatically with the corresponding setpoint fold values which are based on the prepress stage, for regulating purposes. The folder10is then regulated in a fully automated manner, without it being necessary for a printer to intervene.

As an alternative, the actual fold values can also be determined outside the folder10in an offline manner with respect to the folding process. In this case, for example, a folded printed copy is then removed by a printer and measured in the folded and partially folded state with the aid of corresponding measuring devices. Actual fold values which are measured in the process can then be used for the automatic setting of the folder10, as described above.

Accordingly, the present invention provides a method and apparatus for controlling or regulating a folder, in which setpoint fold values are generated on the basis of prepress stage data. Accordingly, the present invention establishes image data-based regulation or control of a folder.

List of Reference Numerals

25Setpoint fold value

26Actual fold value

32Setpoint generating device