JP3370645B2 - Device for managing the registration status of printing plates - Google Patents

Abstract

The arrangement has an attachment device for the front edge of the printing plate (1). The front edge has a stamped-out U-sh aperture (6,7) that can be brought into contact with a stop (4,5) on the plate cylinder. A transducer (8) detects the position o the plate in the attachment device, and detects the front edge outside the region with the aperture and produces a signal if the aperture is at a minimum predefined distance from the stop.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a printing machine according to the preamble of claim 1 and more particularly to a device for managing the registration position of a plate on the plate cylinder of a sheet offset printing machine. is there.

[0002]

In sheet-fed offset printing, the printing start edge of each plate is first fixed to a fixing device, then the plate is stretched around the outer periphery of the plate cylinder, and the printing end edge is fixed. Done. In order to ensure that the individual plates are in register with each other, the leading edge (printing start) is provided with a punching part, which is a registering pin on the plate cylinder or on the fixing device. Co-operates with a form stopper. The printing start edge of the plate is fixed only when the plate abuts the registering pin at its punched part.

In order to automate the plate exchange, a sensor detects the registration status of the plate on the plate cylinder and a corresponding fixing device for the printing start edge of the plate is applied when the plate is registered. It is known to operate only. A device of this kind is known in particular from EP 0551976 or EP 0581212. In these devices, the registering pin or part of the registering pin is arranged to be electrically isolated relative to the plate cylinder as well as to a fixing device for the print start edge, When the plate (punching part) comes into contact with the registration pin, the electric circuit is closed. However, the disadvantage here is that, for example, the presence of dirt as residual ink in the area of the register pin and / or the punched-out area can interrupt the current, which makes it impossible to detect the register status of the plate. Is to become. Damage to the plate in the area of the stamped part also hinders the current and thus the registration of the plate in contact with the stopper (register pin).

The known devices described above for determining the registration of the plates on the plate cylinder of the printing press are preferably used in semi-automatic or fully automatic plate changers. Corresponding to the signal emitted when the plates are registered, the fixing device for the printing start edge of the plates can be closed and subsequently the plate can be stretched to the outer circumference of the plate cylinder. This kind of device for determining the registration status is also assisted when manually changing the plate, i.e. when the operator inserts the plate in the fixing device for the printing start of the plate. And is meaningful. In this case too, the clamping action of the fixing device for the front edge of the plate is carried out only when it is confirmed that the registration has taken place. This can be done while the operator is manually controlling, for example, after the registration state is notified by the display. Also, if a corresponding operating device for the fixing device is assigned to the plate cylinder,
Automatic clamping of the fixing device for the printing start of the plate is also possible.

A disadvantage of the known register management device, in which the registration of the registered plates is confirmed by the connection of the electrical circuit, is that such devices cannot be used in the case of non-conductive plates. This is especially a problem with plates made of plastic film.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to develop an apparatus for managing the registration state of a plate on a plate cylinder of a printing machine based on the concept of claim 1 and to register the plate. The purpose is to enable easy and low-cost confirmation of the state.

[0007]

The above-mentioned problems can be solved by the constituent features described in the characterizing portion of claim 1. Developments of the invention are described in the dependent claims.

According to the invention, a signal generator is assigned to the plate cylinder, by means of which the position of the front edge of the plate occupies a certain area in the feed direction, or It is constructed so that a signal can be emitted when it is crossed. The signal generator according to the invention comprises:
It cooperates with the front edge of the plate outside the punching area assigned to the plate cylinder stopper. If the plate cylinder has two register pins axially spaced from each other, according to one embodiment of the invention, the signal generator to be placed is centered between these register pins. Can be provided. The signal generator is preferably arranged to emit a signal when the edge of the plate still has a certain distance from the punch in the region of the stop. An indication to indicate the registration position of the plate, or an automatic clamping of the fixing device for the front edge of the plate, is provided just as the signal generated by the signal generator remains unchanged for at least a predetermined time interval. When done.

At this time, the knowledge utilized by the present invention is that the plate having the punched portion in the stopper area will surely reach the stopper (register pin) if the propulsive force is continuously applied. is there. When manually changing the plate, i.e. when the plate is supplied to the plate cylinder by the operator, the operator must press the plate against the fixing device opening of the plate cylinder at predetermined time intervals. A signal is emitted by the signal generator of the present invention when the plate is inserted into the fixture with a predetermined minimum depth. If the operator pushes the plate further into the fixing device and this procedure is carried out without hindrance, when the plate exceeds the minimum depth that can be judged by the signal generator, the plate stops at its punching part ( It can be considered that the entire contact with the register pin). The minimum depth of the front edge of the plate in the fixture (measurement area of the signal generator), which can be determined by the signal generator, is determined by carrying out experiments.

The operator who manually replaces the plate does not contact the register pin with the register pin at a predetermined time interval, or inserts it with pressure into the open fixing device (clamp rail). If not, this is displayed on the corresponding display device and prompts the operator to repeat the feeding operation. Similar measures are also provided in an automatic plate changer in which the plates are fed by a transport means in the form of transport rolls, for example. The transport means also feeds the plate with a constant force towards the fixing device (clamp rail) opening so that the front edge of the plate is within the range of the clamp rail to the minimum depth defined by the signal generator (measuring area). It can be considered that the plate is in contact with the stopper even at the punching portion when the temperature reaches at. In this case too, the minimum depth, or the "plate present" signal emitted by the signal generator, should no longer change within a predetermined time. If the signal emitted by the signal generator changes with respect to the position of the plate, this is evidence that the plate feeding process has been compromised. In this case,
It is necessary to remove the plate again from the gripping area of the fixing device by the transport means and repeat the feeding process.

The signal generator of the present invention comprises a mechanical probe,
It can be configured as an optical or inductive sensor, or as a sensor mechanism operating on the light barrier principle. What is important here is to enable the signal generator to emit a signal just when the front edge of the plate occupies a certain minimum distance in the fixing device opening for the front edge of the plate. is there. The signal generator according to the invention can be mounted directly on the plate cylinder or inside a fixing device for the front edge of the plate. It is also possible to arrange the signal generator outside the plate cylinder and to be assigned (illuminated) to the plate cylinder only when a new plate is supplied. In this embodiment according to the invention, the signal generator is suspended on a frame-fixed shaft in front of the plate cylinder and when the plate cylinder is in a corresponding position where it is fed to the plate cylinder, It is assigned to the fixing device of the cylinder or plate cylinder. In this case, the signal generator (sensor) is preferably oriented by means of the centering means. As a result, the signal generator is assigned to the plate cylinder and then positioned in position with respect to the plate cylinder / fixing device so that the position measurement (measurement of the minimum insertion depth of the front edge of the plate) is accurate with respect to the plate cylinder. Guaranteed to be done in.

If the signal generator is located within the area of the plate cylinder, the signal is transmitted from the cylinder by a transducer mounted on the plate cylinder or by any suitable means for transmitting the signal. The evaluation circuit that processes the signal of the signal generator is
It is preferably arranged outside the plate cylinder and is directly connected to a control device (mechanical control device) which controls the plate changing process. The evaluation circuit also evaluates the signal with respect to time, i.e. whether the leading edge of the plate occupies, within a given time interval, the minimum depth defined by the position of the signal generator inside the fixing device. Done. If the signal of the signal generator does not change within a predetermined time, i.e. the front edge of the plate always has a predetermined minimum depth within this time, it represents the abutment of the registered plates. A corresponding signal for generating at the display device, and / or
Alternatively, a signal for automatically clamping the fixing device is generated and sent to the machine controller.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a plate 1, which has two U-shaped punches 6 and 7 at the print start edge. These punches 6, 7 cooperate in a manner known per se with stoppers 4, 5 which are designed as registration pins of the plate cylinder 2, which is drawn from above in FIG. FIG. 1 likewise shows a fixing device 3 for accommodating the front edge of the plate 1.
And the fixing device is configured as a clamping device, for example. In this embodiment, the stoppers 4 and 5 are directly provided on the fixing device (clamp rail).

A signal generator 8 is assigned to the plate cylinder 2 and the fixing device 3, which in the embodiment described here is designed as a distance sensor which operates on the principle of triangulation. There is. Therefore, the signal generator 8 makes it possible to confirm whether or not the object (front edge of the plate 1) is present in the position area 9 (measurement area or detection area) inside the fixing device 3.

If the front edge of the plate 1 is present in the fixing device 3, the signal generator 8 is arranged just when the front edge of the plate 1 reaches the position area 9 of the signal generator 8. Send a signal to the evaluation unit 10. If the front edge of the plate 1 is not inserted deep enough into the fixing device 3, the edge of the plate 1 cannot be detected by the signal generator 8 (positional area 9).

FIG. 2 illustrates the minimum depth of (the front edge of) the plate 1 inserted in the fixing device 3. The detection width of the signal generator 8 (position area 9) is determined by the plate 1 when the front edge of the plate 1 exists in the position area 9 of the signal generator 8 in relation to the stoppers 4, 5 in the fixing device 3. It is selected so that the distances a and b with the stoppers 4 and 5 can still be maintained in the area of the punched parts 6 and 7. In other words, this means that when the plate is in the position shown in FIG. 2, the signal generator 8 already emits a signal that "the plate is present". Therefore, the plate 1 is fully inserted in the fixing device 3 (minimum depth).

If both U-shaped punches 6, 7 have the same depth and the front edge of the plate 1 is oriented parallel to the axis of the plate cylinder 2, the distances a, b are the same. Is.
These intervals a and b are determined by conducting an experiment,
The size and shape of the U-shaped punched parts 6 and 7 and the size and shape of the stoppers 4 and 5 are determined.

When the plate 1 is fed by a predetermined force in the direction of the stoppers 4 and 5 (toward the fixing device 3) by manual or automatic feeding (conveying system), the contours of the punched portions 6 and 7 are finalized. Abutting the stoppers 4, 5. As shown in FIG. 3, at this time, the position region 9 of the signal generator 8 is located beyond the front edge of the plate 1, that is, the signal generator 8 continues to emit the signal "the plate is present".

When the detection signal is evaluated by the evaluation unit 10 which is arranged after the signal generator 8 and the signal generator 8 recognizes the presence of the plate 1 or the front edge of the plate 1, this signal is detected. It should be transmitted at least at predetermined time intervals. Only in that case, for example, a signal "the plate is in contact with the plate in the registered state" is sent to a display device (not shown) provided after the evaluation unit 10. When an actuator that automatically clamps the fixing device 3 is assigned to the fixing device 3, a signal "close the fixing device" may be transmitted.

So far, referring to FIGS. 1 to 3,
Plate 1 (its front edge) defined the minimum depth to be inserted into the open fixation device 3. The signal generator 8 emits the signal "plate present" only when the front edge of the plate 1 is ahead of the position area of the signal generator 8 inside the fixing device 3. The evaluation unit 10 after the signal generator 8 then checks whether the "plate present" signal remains unchanged within a predetermined time interval. If the "plate present" signal remains unchanged within this time interval, it can be considered that the plate 1 has been displaced from the position shown in FIG. 2 to the position shown in FIG. Can be considered to have contacted the stoppers 4 and 5. Since the plate 1 is usually inserted "from above" in the gripping area of the fixing device 3 in a normal sheet-fed offset printing press, at least the deadweight of the plate 1 presses it towards the fixing device 3. Therefore, if the frictional force against this gravity or additional carrying force is not too great, there is a "plate"
It can be considered that the plate comes into full contact with the stoppers 4 and 5 within the minimum time required to output the signal of.

4 and 5 show two possible arrangements of the signal generator 8 with respect to the fixing device 3. Without limiting the generality of the invention, in the embodiment of FIGS. 4 and 5, the fixing device 3 is configured as a clamp rail with a gripping area 11 in the form of a gap. The plate 1 (print start portion) is inserted into the grip area 11 and then clamped. Fixing devices of this kind are known per se and need no further explanation here.

In the embodiment shown in FIG. 4, the signal generator 8 is a plate.
It is arranged in the conveyance direction (supply direction) of 1, that is, in the extension of the gap-shaped gripping region 11. For this purpose, the fixing device 3 (clamp rail) has a notch 12 in the extension of the gripping area 11, through which a signal generator 8 which operates, for example, on the principle of triangulation, is located in the gripping area 11. The front edge of the plate 1 is detected (position area 9).

In the embodiment shown in FIG. 5, the signal generator 8 probes the front edge of the plate 1 in the gripping area 11 perpendicular to the feed direction. The notch 12 through which the measurement radiation of the signal generator 8 passes is correspondingly arranged perpendicular to the gap-like gripping region 11 in the fixing device 3 (clamp rail). In this embodiment, the signal generator 8 may be fixedly arranged on the fixing device 3 or on the plate cylinder 1, not shown. In a further development of the invention, the signal generator 8 is assigned to the fixing device 3 when the plate cylinder is in the angular position for feeding the plate, and the fixing device 3 is provided by additional means not shown. Also, it may be configured to be oriented with respect to the cutout portion 12. This makes it unnecessary to derive the signal of the signal generator 8 from the plate cylinder 1 which is rotatably supported. In this case, the evaluation unit 10 (see FIG.
5 (not shown in FIG. 5) can be directly connected to the signal generator 8. When the signal generator 8 is arranged on the rotatably mounted plate cylinder 1, the signal generator is arranged outside the range of the plate cylinder via a transducer or a suitable radio transmission medium. Connected with 10.

[Brief description of drawings]

FIG. 1 is a schematic view showing an operation method of a signal generator according to the present invention.

FIG. 2 is a schematic diagram showing the cooperation of the plate, the registration pin, and the signal generator.

FIG. 3 is a schematic diagram showing the cooperation of the plate, the registration pin, and the signal generator.

FIG. 4 is a schematic diagram showing a possible arrangement of signal generators for a fixation device.

FIG. 5 is a schematic diagram showing a possible arrangement of signal generators for a fixation device.

[Explanation of symbols]

1 Plate 2 Plate cylinder 3 Fixing device (clamp rail) 4,5 Stopper (registering pin) 6,7 Punching part 8 Signal generator 9 Position area (measurement area or probe area of signal generator 8) 10 Evaluation unit 11 Gripping region (clamping gap of the fixing device 3) 12 Notch portion a spacing (distance between punching portion 6 and stopper 4) b spacing (distance between punching portion 7 and stopper 5)

Front page continued (72) Inventor Helmut Schild Germany 61449 Steinbach / TS im Wingerzgrund 148 (72) Inventor Thomas Kleinschmid Germany 63110 Rotgau Kassel Strasse 29a ( 56) References JP-A-5-193114 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41F 33/14 B41F 27/12

Claims (7)

(57) [Claims] 1. A device for managing the registration of a plate on a plate cylinder of a printing press, in particular a sheet offset printing press, comprising a fixing device for the front edge of the plate. Has a U-shaped punching portion at the front edge, the punching portion being capable of contacting a stopper attached to the plate cylinder, and further comprising a signal generator for detecting the position of the plate in the fixing device. In the device according to claim 1, the signal generator (8) is outside the range of the punches (6, 7) cooperating with the stoppers (4, 5).
Of the signal is generated when the front edge of the punching portion (6, 7) has a predetermined minimum distance (a, b) from the stopper (4, 5). A device characterized in that it is possible to extract a signal from the container (8). 2. The two stoppers (4,5) are axially spaced from each other, and the signal generator is centrally located between the two stoppers (4,5). The device according to claim 1, characterized in that 3. The signal generator (8) is attached to the fixing device (3).
Or the apparatus according to 2. 4. The signal generator (8) is arranged outside the plate cylinder (2) and when the plate cylinder (2) is in a position for feeding the plate (1). 2. A plate cylinder (2) which can be assigned.
Or the apparatus according to 2. 5. The signal generator (8) comprises the plate (1).
5. The device according to claim 1, characterized in that it is configured as a distance probe for detecting the presence of a. 6. The signal generator (8) comprises the plate (1).
Device according to any one of claims 1 to 5, characterized in that it is configured as a sensor which cooperates with the contactlessly. 7. The signal emitted by the signal generator (8) is
An evaluation unit (1) placed after the signal generator (8)
0) The device according to any one of claims 1 to 6, characterized in that it is checked by 0) whether it has changed within a predetermined time.