FR3057490A1 - MACHINE FOR PRINTING A PLURALITY OF OBJECTS AT LEAST PARTLY TRUNCONIC - Google Patents

Abstract

A printing machine (100) for printing a plurality of objects (5), each object having an outer surface (12) to be printed substantially frusto-conical, the printing machine comprising: - a frame (14), - at least one printing station (20C) having at least one inkjet printhead (40) adapted to eject ink jets (44) in a printing direction (D1), the ink jets being aligned in an alignment direction (A) perpendicular to the printing direction, and - a turnstile (16), and object holders mounted on the turnstile, the turnstile being rotatable relative to the frame about a turnstile axis (A2) for successively presenting each object in a printing position, the alignment direction being intended to be substantially parallel to a generator (G) of the object, the object carriers being adapted to rotate the objects on themselves relative to the print head. The turnstile axis is inclined with respect to a horizontal plane (P), and the alignment direction forms with the horizontal plane an oriented printing angle (γ) having an absolute value less than or equal to 2.5 °.

Description

057 490

59933 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number:

(to be used only for reproduction orders) (© National registration number

COURBEVOIE © IntCI ⁸ : B 41 F17 / 28 (2017.01)

PATENT INVENTION APPLICATION

A1

©) Date of filing: 13.10.16. © Applicant (s): MACHINES DUBUIT Company by ©) Priority: simplified actions - FR. @ Inventor (s): TROLIO DIDIER. ©) Date of public availability of the request: 20.04.18 Bulletin 18/16. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ©) Holder (s): MACHINES DUBUIT Joint-stock company related: simplified. ©) Extension request (s): ©) Agent (s): LAVOIX.

MACHINE FOR PRINTING A PLURALITY OF OBJECTS AT LEAST PART TRONCONIC.

FR 3 057 490 - A1 (h /) Printing machine (100) for printing a plurality of objects (5), each object having an external surface (12) to be printed substantially frustoconical, the printing machine comprising:

- a chassis (14),

- at least one printing station (20C) comprising at least one ink jet printing head (40) adapted to eject ink jets (44) in a printing direction (D1), the jets ink being aligned in an alignment direction (A) perpendicular to the printing direction, and

- a turnstile (16), and object holders mounted on the turnstile, the turnstile being movable in rotation relative to the frame around a turnstile axis (A2) for successively presenting each object in a printing position, the alignment direction being intended to be substantially parallel to a generator (G) of the object, the object holders being adapted to rotate the objects on themselves relative to the print head.

The turnstile axis is inclined relative to a horizontal plane (P), and the alignment direction forms with the horizontal plane an oriented printing angle (γ) having an absolute value less than or equal to 2.5 °.

Machine for printing a plurality of objects at least partially frustoconical

The present invention relates to a printing machine for printing a plurality of objects, each object having an external surface to be printed substantially frustoconical around an object axis, the external surface forming a predetermined angle with the object axis. , the printing machine comprising:

- a chassis,

- At least one printing station comprising at least one ink jet printing head suitable for ejecting ink jets in a printing direction, the ink jets being aligned in a perpendicular alignment direction to the printing department, and

- a turnstile, and object holders mounted on the turnstile and adapted to carry the objects respectively, the turnstile being movable in rotation relative to the frame around a turnstile axis to successively present each object in a printing position in which each object presented is facing the print head, the alignment direction being intended to be substantially parallel to a generator of the object presented, the object holders being adapted to rotate the objects respectively around the object axes with respect to the printhead, the object axes and the turnstile axis being substantially parallel to each other.

The invention also relates to a set of such a plurality of objects and of such a printing machine.

The invention finally relates to a corresponding process.

An inkjet printhead has rows of nozzles on its underside. The spacing between each nozzle is equal to the definition, in points per inch (DPI or dot per inch in English). The lower face comprises for example four rows of ninety nozzles each. The two outermost rows are, for example, spaced by 2.82 mm, while the nozzles, in the four rows, are spaced two by two by 0.0705 mm, which leads to a definition of 360 DPI.

The length of a row of nozzles is for example around 72 mm and the width of the underside is for example 17.2 mm. The width of the underside corresponds to the thickness of the print head. The alignment direction extends lengthwise from the underside.

To print objects of revolution, it is known to direct the ink jets towards a generator of the object, and to rotate this object around its axis of revolution.

To ensure good quality printing, the underside of the print head remains close to the surface to be printed, the alignment direction being substantially parallel to the generator in question.

To print a plurality of objects having a frustoconical surface, it is known to place these objects on a turnstile equipped with object holders, the turnstile being rotatably mounted around a horizontal axis to successively present the objects at printing stations , for example to perform a four-color printing.

To simplify construction and adjustments, the object carriers rotate the objects on themselves around an axis parallel to the axis of rotation of the turnstile, that is to say substantially horizontal. As the surface to be printed is frustoconical, the generator towards which the ink jets are directed is inclined relative to the horizontal. The print heads are therefore also inclined to preserve the above-mentioned parallelism between the direction of alignment of the print head and the generator of the objects to be printed.

However, it has been observed that the quality of the printing thus obtained is slightly degraded compared to that obtained using a similar device on cylindrical objects, to the point that the printing is sometimes not in accordance with quality specifications.

An object of the invention is therefore to overcome all or part of the above drawback, by proposing a machine for printing a plurality of objects having a frustoconical external surface making it possible to obtain a better print quality , substantially equivalent to that obtained on cylindrical objects.

To this end, the invention relates to a printing machine as described above, in which:

- the turnstile axis is inclined relative to a horizontal plane, and

- the alignment direction forms with the horizontal plane an oriented printing angle having an absolute value less than or equal to 2.5 °.

According to particular embodiments, the printing machine comprises one or more of the following characteristics, taken alone or in any technically possible combination:

- The printing station further comprises a frame, the printing head being mounted movable in translation relative to the frame in the direction of alignment;

- the alignment direction is substantially horizontal;

- A plurality of successive printing stations, each printing station comprising at least one ink jet printing head adapted to eject ink jets in a printing direction, the ink jets being aligned in an alignment direction perpendicular to the printing direction, the turnstile being adapted to present each object in successive printing positions in which each object is opposite one of the printing heads respectively , and in which the alignment direction of one of the print heads is intended to be substantially parallel to a generatrix of the object presented, each alignment direction forming with the horizontal plane an oriented printing angle having an absolute value less than or equal to 2.5 °;

- Said oriented printing angles respectively have algebraic values in a predefined orientation, the sum of the algebraic values being substantially zero; and

- the turnstile axis forms with the horizontal plane a turnstile angle less than or equal to 6 °.

The subject of the invention is also a set of a plurality of objects and a printing machine as described above, each object having a substantially frustoconical external surface around an object axis, the surface external forming a predetermined angle with the object axis, each object being, in the printing position, facing the print head, and the direction of alignment being substantially parallel to the generator of the object presented.

According to particular embodiments, the assembly includes the characteristic that the turnstile axis forms with the horizontal plane a turnstile angle less than or equal to 6 °.

The invention finally relates to a printing method for printing a plurality of objects, each object having an external surface to be printed substantially frustoconical around an object axis, the external surface forming a predetermined angle with the axis object, the method comprising the following steps:

- supply of a frame and at least one printing station comprising at least one inkjet printing head,

- Provision of a turnstile, and of object holders mounted on the turnstile to respectively carry the objects, the turnstile being movable in rotation relative to the frame around a turnstile axis, the object axes and the axis of turnstile being substantially parallel to each other,

- inclination of the turnstile axis relative to a horizontal plane,

- successive presentation of each object in a printing position in which each object presented is facing the print head,

ejection of ink jets by the print head in a printing direction, the ink jets being aligned in an alignment direction perpendicular to the printing direction, the alignment direction being substantially parallel to a generator of the object presented in the printing position, and the direction of alignment forming with the horizontal plane an oriented printing angle having an absolute value less than or equal to 2.5 °, and

- rotation of objects in the printing position by the object holders respectively around the object axes with respect to the print head.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the appended drawings, in which:

FIG. 1 is a perspective view of an assembly according to a first embodiment of the invention,

- Figure 2 is a partial front view of the assembly shown in Figure 1,

- Figure 3 is a partial side view of the assembly shown in Figures 1 and 2, and

- Figure 4 is a schematic view similar to Figure 3, but of an assembly according to a second embodiment of the invention.

Referring to Figures 1 to 3, an assembly 1 is described according to a first embodiment of the invention.

The assembly 1 comprises a plurality of objects 5 to be printed, and a printing machine 10 to print the objects.

Objects 5 are analogous to each other. Each object 5 has an outer surface 12 substantially frustoconical around an object axis Δ1. Each object 5 is for example a bottle.

The external surface 12 forms a predetermined angle a with the object axis Δ1 which defines the taper of the objects 5 (Figures 1 and 3).

The predetermined angle a is for example non-zero and less than or equal to 8.5 °.

The printing machine 10 comprises a frame 14, a turnstile 16 rotatably mounted on the frame around a turnstile axis Δ2, a plurality of object holders 18 fixed on the turnstile and adapted to carry the objects 5, and a plurality of printing stations 20A, 20B, 20C, 20D, 20E, 20F mounted on the chassis in a circular arc around the turnstile axis Δ2.

As can be seen in FIGS. 1 and 3, the turnstile axis Δ2 is inclined by a turnstile angle β relative to a horizontal plane P. By “inclined” is meant, for example, that the turnstile angle β is greater or equal to 0.5 °.

A horizontal direction X is further defined and located in the same vertical plane P ’as the turnstile axis Δ2. We also define a vertical direction Z and a direction Y such that the coordinate system X, Y, Z is orthogonal direct.

The turnstile 16 is for example of substantially circular shape, advantageously with a recess in the center.

The turnstile 16 is adapted to successively present each object 5 in a printing position in which the object presented is opposite one of the printing stations 20A to 20F. The turnstile 16 comprises a circular plate 22 extending perpendicular to the turnstile axis Δ2, on which the object holders 18 are mounted.

Each object holder 18 comprises for example a mandrel 24 on which one of the objects 5 is threaded.

According to a variant not shown, the object holders 18 are of the cap-tip type known in itself.

The object carriers 18 are regularly distributed on the turnstile 16 around the turnstile axis Δ2. Each object holder 18 is advantageously configured so that the object axis Δ1 of the object 5 carried is substantially parallel to the axis of the turnstile Δ2. In other words, the object holders 18 extend substantially perpendicular to the plate 22.

By "substantially parallel" in the present document is meant that the deviation from perfect parallelism does not exceed, for example, 0.5 °.

The printing stations 20A to 20F are advantageously similar to each other, except that they are configured to deposit specific inks, for example the three primary colors, white and black. In the example shown, there are six printing stations, because two of them are used to deposit a white ink, or one of them is a white ink and another is a varnish .

In the example shown, the printing station 20C is located substantially vertical to the turnstile axis Δ2. The printing stations 20B and 20A deviate angularly from the printing station 20C on one side with respect to the turnstile axis Δ2, while the printing stations 20D, 20E, 20F deviate angularly from the 'other side.

The printing stations 20A to 20F being structurally similar to each other, only the printing station 20C will be described below with reference to FIGS. 2 and 3.

The printing station 20C comprises a frame 30 fixed to the frame 14, a first support 32 (FIG. 3) mounted on the frame 30 and adjustable in height in the direction Z and in inclination around the direction Y thanks to two actuators 34 , 36. The printing station 20C also comprises a head support 38 mounted movable in translation relative to the support 32 in a direction D determined by the inclination of the support 32, and a print head 40 mounted on the support head 38.

A third actuator 42 mounted on the support 32 is adapted to ensure the aforementioned translation of the head support 38 and the print head 40 in the direction D.

According to a variant not shown, the printing station 20C comprises several printing heads offset in the direction D.

The print head 40 is suitable for projecting ink jets 44 (shown only in FIG. 4 similar to FIG. 3) in a printing direction D1.

The printing direction D1 is perpendicular to the direction D.

The ink jets 44 are emitted from a lower face 46 of the print head 40 and are aligned with each other in an alignment direction A extending in the direction of the length of the face lower.

The alignment direction A is perpendicular to the printing direction D1 and substantially parallel to a generator G of the external surface 12 of the object 5 located opposite the print head 40.

Thanks to the characteristics of the printing station 20C, the alignment direction A is adjustable in height in the direction Z and in inclination around the direction Y.

As the printing station 20C is situated vertically of the turnstile axis Δ2, the generator G aimed by the printing head 40 is an upper generator.

In the example shown, the turnstile angle β is substantially equal to the predetermined angle a, so that the generator G, and therefore the direction of alignment A, form with the horizontal plane P a printing angle γ substantially equal to 0 °. In other words, the turnstile axis Δ2 is inclined so that the upper generatrix of the object 5 situated opposite the print head 40 is substantially horizontal. Thus, the alignment direction A is itself substantially horizontal.

The other printing stations 20A, 20B, 20D, 20E, 20F not being situated vertically, above the objects 5 which they print, the printing heads 40 of these printing stations aim at generators which are not completely horizontal, but deviate very little from the horizontal. Two generators G1, G2 have been shown and are those targeted by the ink jets of the printing stations 20B and 20A.

The printing stations 20A, 20B are adjusted so that their alignment direction A is substantially parallel to the generators G1, G2. The alignment directions A of printing stations 20A, 20B are therefore not entirely horizontal, but form printing angles γ less than or equal to 2.5 ° in absolute value.

The operation of the assembly 1 is deduced from its structure and will now be described briefly.

The turnstile 16 places each object 5 successively in the printing positions located opposite the printing stations 20A to 20F. When one of the objects 5 is in one of the printing positions, its object holder 18 rotates it around the object axis Δ for the duration of the printing.

Beforehand, the turnstile 16 has been inclined so that the turnstile axis Δ2 forms with the horizontal plane P the turnstile angle β which is, in the example shown, equal to the predetermined angle a defining the taper of the objects 5.

Thus, the generators G, G1, G2 (and those not shown) targeted by the ink jets form the printing angles γ not deviating by more than 2.5 ° from the horizontal.

Thanks to the three actuators 34, 38, 42, the print heads 40 are positioned so that the alignment directions A are substantially parallel to the target generators. Thus, the alignment directions A of the printing stations 20A to 20F do not deviate more than 2.5 ° from the horizon.

This makes it possible to obtain ink jets 44 which are homogeneous with one another by the same print head 40, which ensures excellent printing quality for each print head 40 of the printing stations 20A to 20F. In fact, it has been observed that an inclination of less than 2.5 ° ensures a sufficiently homogeneous ejection pressure so that the ink jets 44 are themselves homogeneous in intensity and in direction. On the contrary, when the inclination of one of the alignment directions A is strictly greater than 2.5 °, it has been noticed that the print quality deteriorates rapidly.

The case where the turnstile angle β is substantially equal to the predetermined angle a is particularly advantageous when the printing machine comprises only a single printing station located substantially vertical to the turnstile axis Δ2, such as 20C printing station.

When the printing machine comprises other angularly spaced printing stations around the turnstile axis Δ2, it is advantageous to tilt the turnstile axis Δ2 so that the turnstile angle β is strictly less at the predetermined angle a, which constitutes a second embodiment of the invention, of which the assembly 100, described below, is an example.

The assembly 100, represented in FIG. 4, is analogous to the assembly 1 represented in FIGS. 1 to 3. The similar elements bear the same alphanumeric references and will not be described again. Only the differences will be described in detail below.

In the assembly 100, the turnstile 16 is inclined so that the turnstile angle β is not zero and strictly less than the predetermined angle a (while the turnstile angle β is substantially equal to the predetermined angle a overall 1).

Thus, the generator G targeted by the printing head 40 of the printing station 20C 5 is not substantially horizontal. The alignment direction A, parallel to the generator G, forms a printing angle γ which is negative in algebraic value in the orientation shown by the arrow F around the direction Y in FIG. 4.

The printing angles γ1, γ2 formed by the generators G1, G2 have algebraic values greater than the printing angle γ. It is therefore possible to choose the turnstile angle β so that the sum of the algebraic values of the printing angles is substantially zero, each printing angle itself being less than 2.5 ° in absolute value. By "substantially zero" is meant, for example, that the absolute value of the sum is less than or equal to 0.5 °.

In general, the turnstile angle β is chosen to be less than or equal to 6 ° so that the printing angles formed with the horizontal plane P by the generatrices targeted by the print heads are all less than or equal to 2.5 ° in ultimate value.

Such a configuration is particularly advantageous for machines comprising several printing stations, because it makes it possible to minimize the inclination of the alignment directions A relative to the horizontal.

Claims (9)

1 Printing machine (10) for printing a plurality of objects (5), each object having an external surface (12) to be printed substantially frustoconical around an object axis (Δ1), the external surface forming a predetermined angle (a) with the object axis (Δ1), the printing machine (10) comprising: - a chassis (14), - at least one printing station (20A to 20F) comprising at least one ink jet printing head (40) adapted to eject ink jets (44) in a printing direction (D1), the ink jets (44) being aligned in an alignment direction (A) perpendicular to the printing direction (D1), and - a turnstile (16), and object holders (18) mounted on the turnstile (16) and adapted to respectively carry the objects (5), the turnstile (16) being movable in rotation relative to the frame around a turnstile axis (Δ2) for successively presenting each object (5) in a printing position in which each object (5) presented faces the print head (40), the direction of alignment (A) being intended to be substantially parallel to a generator (G) of the object (5) presented, the object holders (18) being adapted to rotate the objects (5) respectively around the object axes (Δ1 ) relative to the print head (40), the object axes (Δ1) and the turnstile axis (Δ2) being substantially parallel to each other, characterized in that: - the turnstile axis (Δ2) is inclined relative to a horizontal plane (P), and - the alignment direction (A) forms with the horizontal plane (P) an oriented printing angle (γ) having an absolute value less than or equal to 2.5 °. 2, -Printing machine (10) according to claim 1, wherein the printing station (20A to 20F) further comprises a frame (30), the print head (40) being mounted movable in translation by relative to the frame (30) in the alignment direction (A1). 3, -Printing machine (10) according to claim 1 or 2, wherein the alignment direction (A) is substantially horizontal. 4, -Printing machine (10) according to any one of claims 1 to 3, comprising a plurality of successive printing stations (20A to 20F), each printing station (20A to 20F) comprising at least one ink jet printhead (40) adapted to eject ink jets (44) in a printing direction (D1), the ink jets (44) being aligned in an alignment direction ( A) perpendicular to the printing direction (D1), the turnstile (16) being adapted to present each object (5) in successive printing positions in which each object (5) is respectively opposite one of the print heads (40), and in which the alignment direction (A) of one of the print heads (40) is intended to be substantially parallel to a generator (G) of the object (5) presented, each alignment direction (A) forming with the horizontal plane (P) a printing angle (γ) oriented with an absolute value less than or equal to 2.5 °. 5. -Printing machine (10) according to claim 4, wherein said oriented printing angles (γ) respectively have algebraic values in a predefined orientation, the sum of the algebraic values being substantially zero. 6. -Printing machine (10) according to any one of claims 1 to 5, wherein the turnstile axis (Δ2) forms with the horizontal plane (P) a turnstile angle (β) less than or equal to 6 °. 7. - assembly (1; 100) of a plurality of objects (5) and a printing machine (1; 10) according to any one of claims 1 to 5, each object (5) having a outer surface (12) substantially frustoconical around an object axis (Δ1), the outer surface (12) forming a predetermined angle (a) with the object axis (Δ1), each object (5) being, in the printing position, facing the print head (40), and the alignment direction (A) being substantially parallel to the generator (G) of the object (5) presented. 8. - assembly (1; 100) according to claim 6, wherein the turnstile axis (Δ2) forms with the horizontal plane (P) a turnstile angle (β) less than or equal to 6 °. 9. - Printing method for printing a plurality of objects (5), each object (5) having an external surface (12) to be printed substantially frustoconical around an object axis (Δ1), the external surface ( 12) forming a predetermined angle (a) with the object axis (Δ1), the method comprising the following steps: - supply of a chassis (14) and at least one printing station (20A to 20F) comprising at least one inkjet printing head (40), - Supply of a turnstile (16), and of object carriers (18) mounted on the turnstile (16) to carry the objects (5) respectively, the turnstile (16) being movable in rotation relative to the frame (14) around a turnstile axis (Δ2), the object axes (Δ1) and the turnstile axis (Δ2) being substantially parallel to each other, - inclination of the turnstile axis (Δ2) relative to a horizontal plane (P), - successive presentation of each object (5) in a printing position in which each object (5) presented is opposite the print head (40), - Ejection of ink jets (44) by the print head (40) in a printing direction (D1), the ink jets (44) being aligned in an alignment direction (A) perpendicular to the printing direction (D1), the alignment direction (A) being substantially parallel to a generator (G) of the object (5) presented in the printing position, and the alignment direction (A) forming with the horizontal plane (P) an oriented printing angle (γ) having an absolute value less than or equal to 2.5 °, and 5 - rotation of the objects (5) in the printing position by the object holders (18) respectively around the object axes (Δ1) relative to the printing head (40). 1/4 2/4