EP0938415B1 - Machine for printing flat objects, in particular envelopes, with printing drum and thickness compensating device - Google Patents

Abstract

The invention concerns a machine comprising two feed rollers (3, 14), one of which at least is a power-operated roller, and a rotating printing drum (6) co-operating with a counter-printing power-operated roller (17). The rollers (17, 14) are borne by the ends of a lever consisting of two yokes, pivoting in its middle (11) and articulated thereat by an articulation with adjustable stop; The displacement of said feed roller (14) following the passage of an envelope (24') between the feed rollers (3, 14) causes the lever to pivot thereby bringing about a corresponding displacement of the counter-printing roller (17), if the latter has not already been displaced by at least said corresponding displacement during the passage of a preceding object (23').

Description

The present invention relates to machines printing of flat objects and, more particularly, mail processing machines for affix a cancellation or franking mark on envelopes, by printing using a rotary marking drum cooperating with a counter roller allowing to obtain the counter-impression effort.

EP-A-0547922, among many others, promotes such an object printing machine thick dishes (in particular envelopes) various brought successively along a table to the by means of a feeding mechanism and printed by means of a printing mechanism, the feeding mechanism comprising at least two rollers, of which at least one roller motorized, between which the objects pass, the printing mechanism comprising a rotating drum and a motorized counter-printing roller.

Machines printing marks cancellation or postage using a rotary drum today use a motorization to train the envelopes and another to drive the print drum. The movement of the drum is described precisely in document WO-A-96/26502. The print drum drive motor performs violent work of acceleration to allow the drum to meet the letter in synchronism perfect. In addition, to allow processing of thick envelopes, the drive motor of the print drum should move the roller from against-printing. As the latter is plated strongly against the drum, the work to be done suddenly by the drive motor is very important.

On the other hand, more and more stepper motors for drum motorization printing. If these have large advantages, they are nevertheless relatively sensitive sudden changes in load.

The object of the present invention is to overcome these various disadvantages, and to significantly decrease the work to be done by the drive motor of the printing drum.

The invention achieves its object in the context of a machine of the type defined above thanks to a device automatic and simple thickness compensation, at know that the axes of the counter-impression roller and one of the two feed rollers are carried by the ends of a lever pivoting in the middle and articulated at this point by a stop joint, such that the movement of said feed roller by following the passage of an object between the two rollers feed causes a pivoting of the lever and therefore a corresponding movement of the counter-impression roller, if it has not already been moved minus said corresponding displacement during the passage of a previous object.

In other words, instead of the work of displacement of the counter-impression roller is carried out by the drive motor of the printing drum, it is partly carried out by the roller motor and the envelope itself when it passes through the feed rollers. So there is a decrease in the required power of the engine drum and increase in the same proportions of the power of the engine driving the envelopes. The technologies of the two engines being very different, economical for envelope training and expensive for driving the printing drum, the present invention thus reduces significantly the cost of the machine.

Advantageously, said compensating lever thick consists of two articulated screeds one on the other by a joint. A screw crosses an extension of one of the yokes to lean on the other, in order to constitute a stop adjustable of said articulation.

Preferably springs remind respectively the rollers carried by the lever towards the contact with the counter roller and the drum printing.

Advantageously, the counter-impression roller is motorized by the motor of the feed roller by means a pulley belt assembly.

• la figure 1 est une vue en coupe développée d'une machine d'impression conforme à l'invention,
• la figure 2 est une vue de devant de la machine de la figure 1,
• la figure 3 est une vue en perspective du levier compensateur conforme à l'invention,
• la figure 4 est une vue schématique de devant de la machine de la figure 1, montrant une première étape du trajet d'une d'enveloppe, à son insertion,
• la figure 5 est une vue analogue de la machine de la figure 1, montrant une seconde étape du trajet d'une d'enveloppe, pendant son impression,
• la figure 6 est une vue analogue de la machine de la figure 1, montrant une troisième étape du trajet d'une enveloppe, après son impression,
• la figure 7 est une vue analogue de la machine de la figure 1, montrant l'arrivée d'une nouvelle enveloppe plus mince que l'enveloppe qui vient d'être imprimée,
• la figure 8 est une vue analogue de la machine de la figure 1, montrant l'arrivée d'une nouvelle enveloppe plus épaisse que l'enveloppe qui vient d'être imprimée.

Other characteristics and advantages of the invention will appear on reading the following description of an exemplary embodiment, referring to the appended drawings in which:

• FIG. 1 is a developed sectional view of a printing machine according to the invention,
• FIG. 2 is a front view of the machine of FIG. 1,
• FIG. 3 is a perspective view of the compensating lever according to the invention,
• FIG. 4 is a schematic front view of the machine of FIG. 1, showing a first step in the path of an envelope, when it is inserted,
• FIG. 5 is a similar view of the machine of FIG. 1, showing a second step in the path of an envelope, during its printing,
• FIG. 6 is a similar view of the machine of FIG. 1, showing a third step in the path of an envelope, after it has been printed,
• FIG. 7 is a similar view of the machine of FIG. 1, showing the arrival of a new envelope thinner than the envelope which has just been printed,
• Figure 8 is a similar view of the machine of Figure 1, showing the arrival of a new envelope thicker than the envelope which has just been printed.

The mail processing machine has a main structure formed by two plates vertical parallel front 1 and rear 1 'connected by spacers 2. This box structure allows the mounting and guiding the various components of the machine.

A horizontal table 22 is mounted at the front, perpendicular to the plate 1, for guiding the envelopes to be printed.

The envelope feed mechanism includes the motor roller 3 mounted at the front of the plate 1 on the shaft 4 which is rotated by the motor 5, arranged at the rear of the plate 1 '.

The printing mechanism includes the drum 6 which is engraved with the mark to be printed. The drum is also mounted on the front of the plate 1, on the shaft 7 rotated by the motor 8 arranged at the rear.

Optionally, an ejection mechanism envelope not shown, conventionally consisting of rollers, can be placed downstream of the mechanism printing.

Figure 3 shows the realization of the lever articulated constituting the compensating device of the invention. It consists of two U-shaped yokes 9 and 10, with cut angles, head to tail mounted and articulated one and the other on an axis 11 screwed into the plate 1 (cf. figure 1) and parallel to trees 4 and 7. The yoke upper 10 wears, on an extension 25 of its back disposed on the side of the joint 11, a screw 12 of which the end 26 is in contact with the inside of the back of the opposite lower clevis 9. The joint 11 is therefore an articulation with adjustable stop allowing the lever constituted by the yokes 9, 10 not to function only in one direction of rotation.

Clevis 9 carries at its end opposite to the articulation 11 a swiveling axis 13 crossing the plate 1 by an appropriate light 27 and at the front end of which is mounted a roller 14. The roller 14 is free and in contact pressure with the drive roller 3 by the action of a tension spring 15 connecting the yoke 9 to a dowel 28 mounted in the plate 1 (see figure 1).

The yoke 10 carries at its end opposite to the joint 11, at the same distance as the axis 13, an axis swiveling 16 on which is mounted the roller counter-printing 17. The counter-printing roller 17 is in contact pressure with the printing drum 6 by the action of a tension spring 18 connecting the clevis 10 to a dowel 29 mounted in the plate 1 (cf. figure 1)

Rotation of the counter-impression roller 17 simultaneous with that of the roller 3 is provided by the motor 5 by means of the assembly consisting of pulleys 19.21 mounted on the respective shafts 4, 16 and of the belt 20 (figure 1).

Figure 4 illustrates the first step in inserting an envelope. Envelope 23 from of a classic unstacking system that does not part of the invention is supported by feed rollers 3 and 14. The rotation of the roller 3 is provided by the motor 5 by means of the shaft 4. The thickness of the envelope 23 constrains the roller 14 to move in the direction of arrow 30, i.e. to rise from its rest position. From this done, yoke 9 rotates clockwise around axis 11, and through the contact of the screw 12 with the inner face of the yoke 9, the yoke 10 also rotates clockwise around the axis 11. Thus, the counter-impression roller 17 moves away of the printing drum 6, downwards, by the value of the thickness of the envelope 23, since the axes of rotation of the rollers 14 and 17 are arranged at equal distances from the axis 11.

Figure 5 shows the next step. The drum 6 is rotated by the motor 8 by through the shaft 7. The envelope 23 is now engaged both in the feed rollers 3, 14 and between the printing drum 6 and the roller counter-printing 17, and the envelope 23 receives printing the drum 6.

Then, as shown in Figure 6, the envelope 23 leaves the feed rollers 3, 14: the action of the return spring 15 brings the roller 14 to the contact of the roller 3, while the counter-impression roller 17 is still in contact with the envelope, which is made possible by the articulation relating to stop of the yokes 9 and 10. Therefore, the mechanism is ready to receive a new envelope.

Figure 7 shows the arrival of an envelope 24 ' thinner than the envelope 23 'which preceded it and is being ejected. Naturally, the roller 14 is free to mount the desired thickness, thanks to the joint 11 which is not blocked because the counter drum 17 had already been moved down a distance corresponding to the thickness of envelope 23 ′, greater than that to which the roller 14 to let the envelope 24 'pass.

Figure 8 shows the opposite case of the arrival of an envelope 24 "thicker than the envelope 23 "which preceded it. The displacement of the roller 14 upwards, larger than in the case previous, is done and therefore spreads even more the roller 17 and the drum 6 from each other, without harmful impact on the previous 23 "envelope, makes printing of it complete.

Claims (5)

1. Machine for printing flat objects (23, 24) of various thicknesses successively fed the length of a table (22) by means of a feed mechanism and printed by means of a printing mechanism, the feed mechanism comprising at least 2 rollers (3, 14), including at least one motorized roller (3), between which the objects (23, 24) pass, the printing mechanism comprising a revolving printing drum (6) and a motorized counter-printing roller (17),
   characterized in that the axes (16, 13) of the counter-printing roller (17) and one (14) of the two feed rollers are supported at the ends by a lever (9, 10) pivoting at its middle and joined at this place by a stop (11, 12) joint, such that the shifting of the said feed roller (14), subsequent to the passage of an object (23, 24) between the two feed rollers (3, 14), causes pivoting of the lever (9, 10) and thus a corresponding shifting of the counter-printing roller (17), if this was not already shifted by at least the corresponding shifting upon-the passage of a preceding object.
2. Machine according to Claim 1, characterized in that said lever is comprised by two covers (9, 10) joined to one another by a joint (11).
3. Machine according to Claim 2, characterized in that a screw (12) crosses an extension of one (10) of the covers in order to be pressed against the other (9), in order to comprise an adjustable stop of the joint (11).
4. Machine according to any of the preceding claims, characterized in that the springs (15, 18), respectively return the rollers (14, 17) toward contact with the opposing roller (3) and the printing drum (6).
5. Machine according to any of the preceding claims characterized in that the counter-printing roller (17) is powered by motor (5) of feed roller (3) by means of a belt-pulley assembly (19, 20, 21).

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