EP0089642B1

EP0089642B1 - A printing machine for labels, tags, cards or the like either for distributing the printed labels or separating such labels from the siliconized support

Info

Publication number: EP0089642B1
Application number: EP19830102706
Authority: EP
Inventors: Emilio Negri
Original assignee: Italora SpA
Current assignee: Italora SpA
Priority date: 1982-03-18
Filing date: 1983-03-18
Publication date: 1985-08-28
Also published as: DE3360645D1; EP0089642A1; IT8221186V0

Description

This invention relates to machines for printing and handling self-adhesive labels, tags, cards or the like for use in identifying articles. For example, these machines are used in preparing tags for cloths articles, or in packaging prepared foods in supermarkets.
The known point and cliche type printing machines are capable of printing self-adhesive labels, tags, cards or the like providing the same either in the form of a roll or previously cut one by one. However such machines (see U.S. Patent N. 4,218,030 to Avery) succeed in providing with printing also the separation of the label only by presetting a complicated labyrinth about the drive roller upstream of the printing device.
Therefore, it is the object of the present invention to provide in a simple and economical way a printing machine allowing both the supply of just printed self-adhesive labels, tags, cards or the like together with the associated support, and the supply of these labels separated from said support.
The above object has been achieved by providing a printing machine, in which the assembly comprising the drive roller for moving the web and the pressure roller adhering to said drive roller is made movable, so that it can be placed at a first position immediately upstream of the printing head and at a second position downstream of the doctor blade, so that the web encircles in the second position the drive roller around a substantial proportion of its periphery.
It is provided in such cases that the printing needle head may be preceded by a buffer or cliché printing device, which presets the fixed text for each label of the like.
Preferably, the second position for the above mentioned roller assembly is such that the web traction produced by the final take up roller will provide a component pressing the pressure roller against the drive roller, thus increasing the web adhesion thereon.
An improvement to the present invention further provides that the take up roller, instead of being conventionally driven by an asynchronous motor through a clutch, is driven by a D.C. motor developing two torques, that is a minor torque when the printing device is writing and the web is stand-still, and a major torque when the stepper motor operating the drive roller moves the web to the next line or to the next label.
The present invention will be more clearly explained with reference to an exemplary embodiment that has been shown in the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of the printing machine according to the invention; and
Fig. 2 is an enlarged view showing the assembly comprising the pressure roller and drive roller.

Referring to the accompanying drawings, it will be seen that reference numeral 10 designates a roller having a web 11 of labels, tags, cards or the like wound up thereon. This web 11 is stretched by a known type of tensioning device comprising an arm 18 oscillating about a pin 12 and carrying a roller 13 which, when required, can recover some length of web 11 holding it taut upstream of the drive roller 20.
Then, this web 11 travels some free distance, during which provision can be made for performing one or more printing operations of a fixed term by means of a cliché or buffer, schematically shown at 19.
Then, said web 11 is caused to pass between the drive roller 20 made of rubber or other high adhesion material, which is driven by a stepper motor (not shown). A pressure roller 21 is pressed against this roller 20 and mounted to resiliently urge against said roller 20. This pressure is exerted, for exmaple, by a spring schematically shown at 22 of Fig. 2.
The whole assembly comprising said rollers 20 and 21 is movable between two positions; that is to say, a position indicated by full line in Fig. 1 immediately upstream of the printing head 14, and another position downstream of the doctor blade 15. This last position has been shown by dash-dot line. Said second position is selected so that the traction force F produced by the motor of the take up roller 17 will produce a component P tending to move said pressure roller 21 near the drive roller 20, thus increasing the adhesion of the web on said roller.
Immediately downstream of the roller assembly 20, 21 a needle printing head 14 is disposed for printing a text which may time by time vary. Downstream of said head 14 a doctor blade 15 is provided for label separation, then a cutting device 16.
During operation, when only the label printing is desired, the web 11 will follow the following path: from said roller 10 the web is caused to pass about roller 13, then between said two rollers 20 and 21, in their full line position, whereupon each label or the like is printed by said head 14, then cut by the cutting device 16.
During the path between said roller 13 and the two rollers 20 and 21 a repetitive printing of an always identical text can be carried out by means of the buffer or cliché 19. This will shorten the printing times of the needle head 14, which can then provide only for writing the variable poriton of each text on the label.
When desiring to provide also for separating the self-adhesive labels, tags or cards from the siliconized support use will be made of doctor blade 15, causing the web 11 to follow a new path, after displacing said rollers 20 and 21 to the second position thereof shown by dash-dot line in Fig. 1. The web will now follow the following path: from roller 10 to roller 13, then directly to the two printing devices 19 and 14, then to doctor blade 15 for separation. Now, the web 11 has to undergo a sudden change in direction, in order to provide the label separation, then winds up on a substantial portion of the drive roller 20 and on the pressure roller 21 resiliently pressed against the roller 20, and finally winds up on the take up roller 17. As it will be seen, in both cases the direction of rotation of roller 20 remains unchanged.
The take up roller 17 may be driven by an asynchronous motor through a clutch limiting the take up torque and preventing the web movement during the writing period of each line.
However, the take up roller could also be operated by a D.C. motor supplied with two current values, so as to provide two different torques, the minor of which will be effective as the printing device is writing, that is when the stepper motor is at stand-still this torque will only serve to maintain the web at stretched out condition. The other higher torque will be effective when said stepper motor rotates and will serve to increase the force required for separation of the label or the like.

Claims

1. A printing machine comprising a drive roller (20) for moving a web (11) and a pressure roller (21) pressing said web (11) against the drive roller (20), characterized in that the assembly comprising the drive roller (20) and pressure roller (21) is movable from a first position immediately upstream of a printing head (14) of the machine to a second position, not interfering in the path of said web (11) before said web reaches said printing head (14) that is a position downstream of a doctor blade (15) for the separation of labels or the like from the web (11), the web (11) encircling in said second position the drive roller around a substantial proportion of its periphery.

2. A printing machine according to Claim 1, characterized in that the printing head is a needle head which is preceded by a buffer or cliche printing device presetting the fixed text for each label or the like.

3. A printing machine according to Claim 1 or Claim 2, characterized in that the second position for the roller assembly (20, 21) is such that the traction provided by the final take up roller (17) will produce a component (P) pressing the pressure roller (21) against the drive roller (20), thus increasing the adhesion of the web (11) thereon.

4. A printing machine according to any of the preceding claims, characterized in that the take up roller (17) is driven by a D.C. motor capable of developing two torques, that is a minor torque when the printing device is writing and the web (11) is stationery, but stretched out, and a major torque when a stepper motor operating the drive roller (20) advances by one or more steps for reaching the next line or the next label.