JP2003521394A - Printing machine for sheet processing - Google Patents

Abstract

The invention relates to a printing machine for processing sheets, comprising at least one flexographic or offset printing cylinder (2) and at least one impression cylinder (1) with at least one feed claw (5) for guiding the sheets. The invention provides a versatile offset or flexographic printing machine for guiding sheets that is simple to adjust and cost-effective to produce, as a result of the fact that, in the guiding position for the sheets, the feed claw is completely enclosed by the cylinder which is defined by the circumferential surface of the impression cylinder.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a sheet processing printing machine comprising at least one flexo or offset printing cylinder and at least one counter pressure cylinder having at least one sheet feeding grip.

[0002]

[Prior art]

Generally, four different printing methods are known. Firstly, letterpress printing methods are known in which the non-printed areas are recessed and are distinguished by the printing elements of the raised print. Lithographic printing is also known in which the printing elements and the non-printing parts of the printing body are (actually) in one plane. Gravure printing methods, in which the printing elements of the printing body are recessed, are particularly widespread in newspaper printing. Finally, so-called screen-printing or silk-screen printing methods are also known, in which at the place of printing, the color is transferred through the mesh holes of the print onto the material to be printed.

In addition to letterpress printing, letterpress printing methods include so-called flexographic printing or aniline printing in which the printed body is flexible.

At present, conventional offset printing is included in the lithographic printing field. By suitable treatment, the areas to be printed are made to attract oil, i.e. suck up the (ink-like) printing ink when filled with ink, while the areas not to be printed are oil repellent, i.e. Repel. In the case of sheet-fed printing machines or sheet-printing machines, the sheets are individually removed from the stack and transported by a transport cylinder to a crimping or counterpressure cylinder located opposite the printing cylinder. During this process, the printing ink already applied to the printing cylinder is transferred to the sheet.

Commercially available sheet-fed flexo and offset printing machines have a printing cylinder with at least one axially extending recess, a so-called plate mounting groove. A flexible printing plate is mounted in the plate mounting cylinder between two adjacent grooves.

To enable the transport of sheets, the counter pressure cylinder typically has a gripper consisting of a gripping arm and a gripping pad. The gripper is also located in a recess in the crimp cylinder. During the transport and the respective gripping process, the transported sheet is positioned such that its surface faces the counter pressure cylinder on the gripping pad. The gripping arm is pushing on the surface of the sheet away from the gripping pad. If the counterpressure cylinder now rotates, the sheet is conveyed by the gripper holding the sheet between the gripping pad and the gripping arm. All conventional sheet-fed offset printing or flexo printing machines to print the sheet as close as possible to the edge of the sheet and to improve positioning accuracy so that the sheet does not fold Has been taken into consideration. Therefore, the gripping arm that grips the sheet on the surface of the sheet remote from the counter pressure cylinder is always positioned outside the outer contour of the counter pressure cylinder, and the grip arm is projected above the recess in the counter pressure cylinder. . However, since the printing cylinder and the counter-pressure cylinder lie directly opposite one another, the result is that the gripping part always projects into the outer contour of the printing cylinder. This is not a disadvantage in conventional flexo or offset sheet printing machines. This is because, as described in the introduction, the printing cylinder or plate mounting cylinder has a recess in the form of a plate mounting groove into which a gripping portion protruding into the contour of the counterpressure cylinder can be inserted.

In contrast to sheet-fed printing machines, reel-fed printing machines have a print cylinder without depressions. Since it is not necessary to hold the individual sheets in the case of a reel-fed printing machine, the grip on the crimping or counterpressure cylinder can be dispensed with.
As a result, the parts of the grip do not project beyond the outer contour of the counter pressure cylinder,
The absence of recesses in the plate mounting cylinder does not prejudice. Instead of an installed plate, so-called sleeves with a cylindrical shape are used in reel-fed printing machines and surround the entire printing cylinder. In this way, for example, the paper on the reel can be continuously printed.

However, the known sheet feed offset and flexographic printing machines have disadvantages. That is, on the one hand, the flexible printing plates must be individually adjusted on the plate mounting cylinder, and on the other hand, in the rest position the gripping arms project beyond the outer contour of the counterpressure cylinder. The counter-pressure cylinders of the known offset and flexo sheet printing machines cannot be used for other printing methods, and the printing cylinders must have immutable depressions. However, such indentations are unacceptable, for example, in gravure printing where the printing cylinder must be dipped in the ink and the excess ink "wipe" away.

[0009]

[Problems to be Solved by the Invention]

It is therefore an object of the present invention to provide a sheet-fed offset printing or flexographic printing machine which is versatile, easy to adjust and inexpensive to manufacture.

[0010]

[Means for Solving the Problems]

This object is solved by the invention in that the gripping part is entirely arranged in the cylinder described by the peripheral surface of the counterpressure cylinder in the sheet feeding position.

The peripheral surface of the counterpressure cylinder is here understood to be the part of the surface of the counterpressure cylinder which is located opposite the printing cylinder. Alternatively, the counterpressure cylinder may comprise a region of smaller radius in which the peripheral surface of the counterpressure cylinder describes a cylinder of smaller radius. However, in this case it means the area on the counter pressure cylinder where the sheet is located during the printing process.

Since the gripper is now arranged in the contour of the counterpressure cylinder, ie, does not project above the recess, the recess in the printing cylinder or the respective plate mounting groove can be omitted if desired. Therefore, it is possible to use sleeves instead of flexible printing plates, as is already known in reel-fed printing presses.
However, it is not possible to use the entire outer printing surface of the sleeve, as it is necessary to leave a gap between the sheets so that the gripping arms engage between the sheets for transporting the sheets. As a result, the sleeve must also have non-printed areas. Therefore, at least in the flexographic printing method, the sleeve must be specially manufactured and used for sheet printing.

This novel arrangement of the offset and flexographic grips has the additional advantage that it makes it possible to use the counterpressure cylinder in other printing processes, for example in the gravure process. Therefore, for example, the flexographic cylinder or the offset printing cylinder can be easily replaced with the gravure printing cylinder without making any changes to the sheet feeding mechanism.

The counter pressure cylinder of the present invention can be used in both reel-fed and sheet-fed printing machines. In addition, it is possible to quickly change the sheet-fed printing machine to a reel-fed printing machine and vice versa, if desired. Preferably, when using the gripper of the present invention in a reel-fed printing press, a counter pressure cylinder for receiving the gripper by a device that can be combined with the gripper arm to increase the area printed on the web. May be at least partially closed.

Since the grips are arranged radially low, there is always a slight amount of bending of the sheet in the grip area, ie the edge area of the sheet. However, the bent portion does not unexpectedly affect the accuracy of alignment. further,
In this way, the edges of the non-printable sheet will always expand somewhat.

Due to the arrangement according to the invention, the paper supply made by the gripper is radially further inside the so-called printing area, ie the area on which the sheet is printed. When constructing a printing press, it must be taken into account that the printing area and the sheet feeding area have the same angular velocity but different rotational speeds. For this reason, in general, two separate drives (eg gear drives) must be provided, both for sheet feeding and for printing circumference.

For a fast and reliable gripping of the sheet, it is advantageous for the gripper to consist of a gripping arm and a gripping pad, at least so that the gripping arm is movable relative to the gripping pad. The gripping arm may be arranged, for example, so as to be rotatable around the rotation axis. As soon as the seat is located on the grip pad, the grip arm swings onto the grip pad so that the seat is clamped between the grip pad and the grip arm. When the printing cylinder and the counter pressure cylinder rotate at the same angular velocity and in opposite directions, the sheet is advanced between the printing cylinder and the counter pressure cylinder with the aid of a gripper to be printed at the same time.

It will be appreciated that alternatively the gripping arm may be fixed and the gripping pad movably arranged for a particular application. Alternatively, it is also advantageous for the gripping pad and the gripper to move in order to securely grip the sheet.

For some applications it is advantageous to place at least one cylinder in the path of the sheet. In this way, the printing cylinder is easily accessible in order to allow easy replacement of the printing plate or sleeve.

Particular preference is given to embodiments in which at least one flexographic or offset printing cylinder optionally equipped with an ink supply can be replaced by a gravure printing cylinder with a suitable ink supply. The printing press can be switched as needed depending on the application. Thus, for example, a plurality of flexographic or offset printing cylinders, or even gravure printing cylinders, can be selectively placed behind the corresponding drying device. If desired, it is possible to combine the gravure printing cylinder and the flexographic printing cylinder as a so-called sheet-fed mixed printing machine. A sheet-fed mixed printing press that combines the quality benefits of gravure printing with inexpensive flexo or offset printing can be easily implemented in accordance with the present invention.

Depending on the application, it is advantageous to adjust the gripper or the gripping pad, respectively, so as to position the gripping arm radially inside or outside the outer contour in the sheet feeding position, depending on the particular need. Is. Thus, when a plate mounting cylinder with recesses or plate mounting grooves is used as the printing cylinder,
The grip portion can be arranged so that the sheet is not folded or bent in the grip area. This is particularly advantageous when using fairly stiff sheets. In this case, the printing press is preferably equipped with at least one adjustable counterpressure cylinder so that the peripheral speed of the paper feed corresponds to the peripheral speed of the printing circumference, with at least some clearance between adjacent transport cylinders. It can be changed with.

[0022]

DETAILED DESCRIPTION OF THE INVENTION

Further advantages, features and possible applications will become apparent from the description of the preferred embodiment and the associated drawings.

In FIG. 1, the outer shape of the pressure-bonding or counter-pressure cylinder is indicated by the broken line 1. The dashed line 2 indicates the outer contour of the printing cylinder. The supplied sheet 3 is fixed at the position shown between the grip pad 4 and the grip arm 5. The gripping part, that is, the gripping pad 4 and the gripping arm 5 are connected to a counter pressure cylinder. When the printing cylinder 2 and the counter pressure cylinder 1 move at the same peripheral speed in the direction of the arrow, the sheet 3 moves between the printing cylinder and the counter pressure cylinder to print. It is clear that the gripping arm is arranged to pass radially inside the outer contour 1 of the counterpressure cylinder. Thus, as can be seen in the figures, the sheet necessarily bends or folds slightly in the end areas. Numerous tests have shown that this minimal sheet bending does not cause registration problems in flexographic or offset printing.

As already mentioned in the introduction, it is advantageous to be able to adjust the gripping pad. At the sheet feeding position of the gripping portion shown in FIG. 2, the gripping pad moves radially outward. This position substantially corresponds to the position of the gripper in a conventional sheet-fed printing press. As can be seen, the gripping arm projects above the recess of the counterpressure cylinder. At this position, the edge area of the sheet where printing is not possible is minimal.

Compared to the position shown in FIG. 1, this position has the advantage that the sheet does not fold in its end regions. However, this setting of the gripper is only possible when the corresponding printing cylinder has a recess 6, for example a plate mounting groove 6. Depending on the printing cylinder used, the optimum position of the gripper can always be set by adjustment.

According to the invention, the flexibility of sheet-fed flexographic and sheet-offset printers is greatly increased. Thus, for example, all known printing methods can be combined in one printing machine as desired. As mentioned above, in particular embodiments,
Have a retroactive replacement of the printing press. In this way, depending on the required printing, it is possible to select whether the printing is gravure printing, flexographic printing or offset printing in each individual printing stage component.

[Brief description of drawings]

[Figure 1]   4 illustrates an arrangement of gripping portions of the present invention.

[Fig. 2]   The other sheet supply position of the grip part is shown.

[Explanation of symbols]

        1 pressure cylinder         2 Flexographic printing or Oyaset printing cylinder         3 sheets         4, 5 sheet gripping parts (4 gripping pads, 5 gripping arms)

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Cleck, Herbert, Kei             65385 Rüdescha, Federal Republic of Germany             Im Am Rhein, Am Engelgra             Ben, 1 F-term (reference) 2C020 AA05

Claims (11)

[Claims] 1. A sheet processing printing machine comprising at least one flexographic or offset printing cylinder (2) and a counter pressure cylinder (1), wherein the counter pressure cylinder (2) comprises at least one sheet feed gripper (1). 4, 5), characterized in that, in the sheet feeding position, the gripping parts (4, 5) are arranged entirely within a cylinder described by the circumferential surface of the counterpressure cylinder (1). Machine. 2. The gripping part (4, 5) comprises a gripping arm (5) and a gripping pad (4).
2. Press according to claim 1, characterized in that it consists of at least a gripping arm (5) movable with respect to the gripping pad (4). 3. Printing machine according to claim 2, characterized in that the gripping pad (4) is movable with respect to the counterpressure cylinder (1). 4. A printing machine according to claim 1, wherein at least one printing cylinder (2) is arranged in the path of the sheet. 5. A printing machine according to claim 1, wherein at least one flexographic printing cylinder or offset printing cylinder (2) is replaceable with a gravure printing cylinder (2). 6. Printing machine according to claim 1, characterized in that there is at least one gravure printing cylinder (2). 7. The sheet feed position of the grips (4, 5) is adjustable, and there is generally at least one sheet feed position of the grips in a cylinder described by the circumference of the counter pressure cylinder (1). The printing machine according to claim 1, wherein the printing machine is a printing machine. 8. A printing machine according to claim 1, wherein at least one flexographic or offset printing cylinder (2) does not have a plate mounting groove (6). 9. A printing machine according to claim 1, wherein at least one flexographic printing cylinder (2) or offset printing cylinder is capable of receiving a sleeve. 10. Printing machine according to claim 1, wherein the printing machine is capable of supplying reels after the printing cylinders (2) have been replaced. 11. Printing machine according to claim 1, characterized in that separate drive systems are provided for sheet feeding and printing area.