Device for printing one or several objects moving in a feed direction

ES 2 289 360 T3

DESCRIPTION

Device for printing one or more objects that can move in a forward direction.

The invention relates to a device for printing one or more objects that can move in a forward direction, especially labels, containers, container sections, a strip or adhesive labels on a support strip, with a thermal printing head and means to feed the object to be printed to the thermal print head, as defined in particular in the preamble of claim 1.

Such a device is known for example from US 6431773 B1. In the case of the device according to DE 195 07 892 A 1, a label strip, consisting of a carrier strip with removable adhesive labels on it, is guided through between a thermal printing head and a printing cylinder. compression and is printed in the thermal or thermal transfer process. The labels are then separated from the support band by means of a separation device, the latter leading around a dispensing edge. The print head is stationary fixed in the device and remains during printing in the thermal process for the entire transport and printing time, on the label or the support strip.

Furthermore, devices according to the generic type are known, in which the printing head is raised from the label and from the support strip during the times when it is not printed.

The print speed of a thermal printer is limited in terms of print quality. Additionally, heat bar wear increases as speed increases.

Document US 6,431,773 B1 discloses a device for printing an object that can be moved in a forward direction, with a print head and means for feeding the object to the print head. In the described embodiments, the device is configured as a plotter ("plotter") having a print head. As a possible embodiment of the recording head, a thermal recording head is also mentioned in this document. The device comprises a frame defining a working support surface, as well as means for continuously conveying web-shaped work material, to be printed, in a first coordinate direction running in its longitudinal direction across the surface. work support. An elongated support with a first and a second end is attached to the frame and runs transversely across the working support surface. The print head is attached to the holder in such a way that it can move between its first and second ends. A control, in which graphic data is stored, provides instructions to the device to control the positional relationship of the print head with respect to the support and work material. During operation, the combined movement of the print head and work material, as instructed by the control, causes the print head to print successive linear sections of a graphic, which are oriented nearly perpendicular to the first direction of the print. coordinate.

The objective of the present invention is to improve a device of the type mentioned at the beginning in the sense that, without reducing the quality of the printing and / or without increasing the wear of the thermal bar, it offers a higher printing performance or labeling performance. .

This objective is solved by a device with the characteristics of claim 1. The thermal printing head of the device according to the invention is provided with a drive, by means of which the thermal printing head can move in parallel to the direction of advance of the object to be printed both in its feed direction and against its feed direction. The drive is assigned a control that controls it in such a way that the thermal print head has, in the event of a movement parallel to the direction of advance of the object, the same speed as the moved object or a lower speed than the moved object . Furthermore, the device according to the invention is characterized in that the thermal printing head, in case of moving against the direction of advance of the object, moves with a separation with respect to the object or adhesive labels therein.

In this regard, means for detecting the advance speed of the object to be printed may preferably be provided, which send measurement signals proportional to the advance speed to the control, the control controlling the movement of the print head as a function of the speed. progress detected.

A further advantageous configuration of the device according to the invention is characterized in that the drive, by means of which the print head can move in the direction of advance as well as against the direction of advance of the object to be printed, has a mechanism of connecting rod and crank or a piezoelectric actuator. With a crank-rod mechanism, particularly fast forward and backward-facing forward movements of the print head can be reliably carried out in parallel with the direction of advance of the strip. The same applies for a piezoelectric actuator.

An advantageous development of the device according to the invention also consists in that the stroke length of the crank-rod mechanism can be adjusted. This configuration makes it possible to adapt the forward and backward movement of the print head in parallel to the direction of advance of the object to be printed, for example as a function of the length of the label and / or the spacing of the adhesive labels on the strip, to be printed.

A preferred configuration of the device according to the invention also consists in that the print head is placed on a support housed in a sliding guide, which also supports the drive by which the print head can move towards the object to be printed and from the object. This drive can in this case have a toothed disk or a circular disk with an eccentrically arranged axis of rotation, by means of which the print head can be brought into contact with the object to be printed, against the effect of at least one element of rotation. spring, preferably a helical spring.

Instead of a compression cylinder, such a co3

ES 2 289 360 T3 mo is present in devices according to the conventional generic type that have a stationary print head, a plate-shaped counter bearing can be arranged in the device according to the invention, opposite the print head, on the one that slides the back side of the strip during its advance.

Other preferred and advantageous configurations of the device according to the invention are indicated in the dependent claims.

The invention is explained in more detail below with the aid of a drawing showing various embodiments. They show:

FIG. 1 a schematic representation, not scaled, of a device according to the invention according to a first embodiment, and FIG. 2, a schematic representation, not scaled, of a device according to the invention according to a second example of realization.

Figure 1 shows a device for printing adhesive labels 2 on a support strip 1. The labels 2 are placed on the strip 1 with an essentially uniform spacing from each other. The strip 1 is unwound from a supply roll 3 and fed to a printing mechanism. The printing mechanism consists of a printing head 4 in the form of a thermal printing head and a plate-shaped counter bearing 5, having a smooth surface, on which the rear side of the strip 1 slides during its advancement. The recording head 4 is configured in the form of a bar and extends transversely to the direction of advance of the strip 1, essentially over its width or the width of the labels. The printing head 4 presses the labels 2 with sufficient force against the fixedly arranged plate-shaped counter bearing 5 and prints them for example in the thermal or thermal transfer process. In the direction of movement of the web behind the printing mechanism, a relatively sharp deflection is provided in the form of a dispensing edge 6, in which the printed labels 2 can be detached from the carrier strip 1 in a manner known per se and taken out through an opening in the housing of the device and placed over an object to be marked. The support strip 1 is wound after deflection at the dispensing edge 6 on a winding roll 8 driven by a stepping motor 7 of a winding device. The rotational speed of the stepper motor 7 or of the winding roll 8 can preferably be continuously adjusted.

The thermal print head 4 is clamped on a plate-shaped support 9, which is housed in a sliding guide 10. The slide guide 10 shown schematically can be formed, for example, also of roller bearings. The support 9 is provided with a drive, by means of which it, and therefore the print head 4, can move in parallel in the direction of advance as well as against the direction of advance of the strip 1. This is indicated by the double arrow. In the embodiment shown, the drive comprises a stationary motor 11, preferably an electric motor, the motor shaft 12 of which drives a circular disk 13. The circular disk 13 has an eccentrically arranged stem 14 in which one end of an articulated rod 15 is articulated. The other end of the articulated rod 15 is articulated with a stem 16 placed in the support 9. The circular disk 13 with the stem 14 disposed eccentrically, the rod 15 articulated thereto and the support 9 housed in a sliding guide with the articulated stem 16 placed therein, therefore form a connecting rod and crank mechanism. The distance between the axis of rotation of the motor shaft 12 and the midpoint of the articulated rod 14 positioned in the circular disc 13 determines the stroke length of the connecting rod and crank mechanism.

In order to be able to move the print head 4 if necessary with different stroke lengths in the direction of advance as well as against the direction of advance of the support strip 1, the spacing of the articulated rod 14 with respect to the axis of rotation of the The drive shaft 12 is adjustable and the articulated stem 14 is correspondingly housed in the circular disc 13 so that it can be displaced as well as fixed.

A control 17 is assigned to the drive motor 11 which controls the drive in such a way that the print head 4, in case of movement in the forward direction of the support strip 1, has the same speed as the support strip 1 or a speed lower than the support strip 1. Reference numerals 18 and 19 designate a light-emitting emitting diode and a light-reacting receiver diode, which are part of a measuring device for detecting the speed of advance of the support strip 1. Labels 2 spaced from each other essentially uniformly or other markings spaced from one another evenly on the support strip 1 interrupt the reception of the light emitted by the emitting diode 18 in the receiving diode 19, if the strip is configured in such a way transparent. If the receiving diode is to receive the light emitted by the emitting diode due to light reflection on the labels 2 or the other unlabeled sections 20 of the support strip 1, then, unlike the representation in the drawing, it is arranged together with the emitting diode on the side of the support strip 1 facing the labels 2. As an alternative to diodes 18 and emitter and receiver, other means may also be used to detect the forward speed of the support strip, for example a dynamo or the like rolling on the support strip.

The receiver diode 19 or the dynamo deliver measurement signals, which are proportional to the speed of advance of the support strip 1. These signals are fed to the measuring and control device 17, which controls the speed of rotation of the motor shaft 12 and, thus, the translational movement of the support 9 and the print head 4, as a function of the detected advance speed of support strip 1.

The support 9 is equipped with a device by which the recording head 4 can move towards the support strip 1 and from the support strip 1. This device is also connected via a signal line 21 with the measuring and control device 17 and comprises an electric motor 26, preferably a stepper motor, and a circular disk 27 with eccentrically arranged axis of rotation. 28 designates a mounting configured on the support 9 for the motor 26. The support 9 is represented in the drawing in longitudinal section. The print head 4 is provided with rods 29, 30 which dis5

ES 2 289 360 T3 run parallel to each other, which are guided in sliding bearings configured in the support 9. The upper ends of the rods 29 are connected to each other through a transverse rod. Between the support and the transverse rod, a spring element 32 in the form of a helical spring is arranged, which moves the recording head 4 away from the strip. By means of the eccentrically mounted circular disc 27, which engages on the upper side of the transverse rod 31, the print head 4 can come into contact, against the effect of the helical spring 32, with the support strip 1 or the label 2 to be printed in each case.

The measuring and control device 17 controls the drives so that the print head 4, moving in the forward direction of the support strip 1, rests on an adhesive label 2 on the support strip, to be printed , and by moving against the direction of advance of the strip 1, it moves with a gap with respect to the support strip or the adhesive labels 2 therein.

The exemplary embodiment shown in FIG. 2 differs from the exemplary embodiment according to FIG. 1 only in that, instead of the electric motor 26, the circular disk 27 housed eccentrically, the mounting 28, the parallel guide formed by the rods 29, 30 and the transverse rod 31 as well as the spring element 32, at least one piezoelectric actuator 33 is used to raise and lower the recording head 4. The thermal print head 4, in figure 2, is fixed to at least one piezoelectric actuator 33, which in turn is clamped on the underside of the plate-shaped holder 9. The support 9 is in turn housed in a sliding guide 10. Instead of a slide guide 10, however, as already mentioned, a roller bearing can also be used.

The invention is not limited in its embodiment to the embodiments described above. Rather, various variants are conceivable within the framework of the inventive idea, as defined in the claims. Especially, the invention is not limited to the printing of adhesive labels on a carrier strip. The invention can also be applied also in the printing of continuous paper provided on one side with an adhesive (called for lamination), individually fed labels without backing paper as well as coatings of packages of paper or cardboard that are to be partially printed.

Reference number list

Support strip

Label

Provisioning roll

Print head (thermal print head)

Counter bearing

Vending edge

Stepper motor

Winding roll

Medium

Sliding guide

Motor ¹² Motor shaft

Circular disc

Articulated stem

Articulated rod

Articulated stem

Control (measuring and control device)

Emitting diode

Receiver diode

Strip section without label

Signal line

Signal line

Signal line

Signal line

Signal line

Electric motor

Circular disc

Fixation

Dipstick

Dipstick

Cross rod

Spring element (coil spring)