EP4695093A1

EP4695093A1 - Printer for slab-shaped manufactured articles

Info

Publication number: EP4695093A1
Application number: EP24725008.7A
Authority: EP
Inventors: Davide Ferrari
Original assignee: Spider Jet Srl
Current assignee: Spider Jet Srl
Priority date: 2023-04-14
Filing date: 2024-04-12
Publication date: 2026-02-18
Also published as: IT202300007227A1; WO2024214061A1

Abstract

The printer (1) for slab-shaped manufactured articles comprises: a line of forward movement (8) of a slab-shaped manufactured article (M); a printing head (10) comprising: at least one base structure (11) arranged on top of the line of forward movement (8); a plurality of printheads (13) associated with the base structure (11) and adapted to dispense a printing fluid onto the slab-shaped manufactured article (M); and anti-crash means (16) associated with the base structure (11) and comprising a slab-shaped element (17) associated inferiorly with the base structure (11) and in a removable manner between a first position, wherein it is lowered and spaced apart from the base structure (11), and a second position wherein it is raised and placed in contact with the base structure (11) as a result of the crash of the printing head (10) with the slab-shaped manufactured article (M).

Description

PRINTER FOR SLAB-SHAPED MANUFACTURED ARTICLES

Technical Field

The present invention relates to a printer for slab-shaped manufactured articles. Background Art

There is a particular need in many industries to decorate slab-shaped manufactured articles by means of printers dispensing a printing fluid onto them.

The printing of slab-shaped manufactured articles is implemented to change the aesthetic appearance of the manufactured articles through the creation of special decorations and/or to make visible on the same manufactured articles commercial and/or merchandise information and/or the manufacturer’s logo.

In the context of this disclosure, the expression “slab-shaped manufactured article” should be understood to mean any product of flattened conformation having two dimensions of spatial extension (i.e., width and length) significantly bigger than the third dimension (i.e., thickness).

Particularly, within the scope of this disclosure, special slab-shaped manufactured articles made in sheets are referred to, that is, in which the thickness is extremely small compared to their length and width.

In this sense, sheet slab-shaped manufactured articles consist of, e.g., paper sheets, sheet metal, fabric elements.

Such slab-shaped manufactured articles are provided with a substantially flat printable surface on which printers dispense the printing fluid of the type, e.g., of an ink.

Printers for slab-shaped manufactured articles of known type generally comprise a line of forward movement defining a substantially horizontal supporting plane and on which the slab-shaped manufactured articles are placed with the printable face facing upwards.

The line of forward movement moves the slab-shaped manufactured articles along a substantially horizontal direction of movement to bring them to a printing head with which the printers of known type are provided.

The printing head comprises a base structure, arranged on top of the line of forward movement, and a plurality of printheads associated with the base structure and each comprising a plurality of dispensing nozzles adapted to dispense the printing fluid onto the slab-shaped manufactured article.

Preferably, the printing head is positionable on the line of movement as a result of relevant shift along one axis of shifting which is substantially horizontal and orthogonal to the direction of movement.

To improve the dispensing of the printing fluid from the dispensing nozzles and the quality of the decoration obtainable on the printable surface, it is preferred to place the dispensing nozzles very close to the printable surface.

During the mutual movement of the printing head and of the slab-shaped manufactured article, it may happen that the dispensing nozzles collide with any protruding portions of the slab-shaped manufactured article.

In particular, such protruding portions may consist of foreign products to the slabshaped manufactured article that have settled on the printable surface (i.e., glue) and/or of irregular portions of the slab-shaped manufactured article itself.

For example, in the case where the slab-shaped manufactured article is of the type of a sheet metal it often happens that the angular portions of the latter raise generating protruding portions.

Again, in the case where the slab-shaped manufactured article consists of a fabric it may happen that the latter partly folds on itself leading to the formation of protruding portions.

Conveniently, the printers of known type are provided with anti-crash means that are associated with the base structure of the printing head and that are usable to detect a crash of the latter with a protruding portion of the slab-shaped manufactured article. Generally, the anti-crash means of known type comprise a first anti-crash bar and a second anti-crash bar associated with a respective edge of the base structure arranged transversely to the axis of shifting.

The anti-crash bars detect any protruding portions from the manufactured article during the shift of the printing head in either way of shifting.

As a result of the anti-crash bars colliding with the slab-shaped manufactured article, the anti-crash means activate an emergency configuration of the printer.

Such an emergency configuration may, e.g., consist of a blockage of the mutual movement of the printing head and of the slab- shaped manufactured article and/or of an audible and/or visual alarm indicating the need to remove the slab-shaped manufactured article from the line of forward movement.

However, the printers for slab-shaped manufactured articles of known type do have some drawbacks that are mainly related to the possible damage that the dispensing nozzles may suffer during the use of such printers.

In particular, the anti-crash means with which the printers of known type are provided are unable to detect any protrusions that may form when the printheads and the relevant dispensing nozzles are arranged on top of the slab-shaped manufactured article.

For example, in the case where the slab-shaped manufactured article is of the type of a fabric, the latter may fold on itself under the nozzles.

In the case where the slab-shaped manufactured article is of the type of a sheet metal this may form folds under the nozzles.

Such protrusions arranged under the dispensing nozzles may nick and damage them, necessitating their repair or replacement.

Such maintenance procedures often turn out to be time-consuming and costly and inevitably lead to an aggravation of the cost of the printing procedure for the slabshaped manufactured articles.

Description of the Invention

The main aim of the present invention is to devise a printer for slab- shaped manufactured articles which allows reducing the occurrence of damage to dispensing nozzles.

Another object of this invention is to devise a printer for slab-shaped manufactured articles which allows detecting any protruding portions from the slab-shaped manufactured article that may be formed when the printing head is already placed on top of the slab-shaped manufactured article itself.

A further object of this invention is to devise a printer for slab-shaped manufactured articles which allows reducing the frequency of maintenance operations concerning the printing head, particularly the dispensing nozzles, and reducing their cost.

Another object of this invention is to devise a printer for slab-shaped manufactured articles which allows the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use, as well as cost- effective solution. The above objects are achieved by this printer for slab-shaped manufactured articles having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a printer for slab-shaped manufactured articles, illustrated by way of an indicative, yet non-limiting example in the attached tables of drawings in which:

Figure 1 is an axonometric, partly cutaway view of the printer according to the invention;

Figure 2 is a top, partly cutaway view of the printer according to the invention;

Figure 3 is an axonometric, partly cutaway view of the printer according to the invention from a different angle than Figure 1;

Figure 4 is a cross-sectional view of the printer according to the invention;

Figure 5 is an axonometric view of some components of the printer according to the invention;

Figure 6 is an axonometric view from below of some components of the printer according to the invention;

Figure 7 and Figure 8 are side, partly enlarged views of some components of the printer according to the invention in a first position and in a second position, respectively;

Figure 9 is a cross-sectional view of some components of the printer according to the invention.

Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally denotes a printer for slab-shaped manufactured articles.

Within the scope of this disclosure, it was considered that the printer 1 is used to dispense a printing fluid onto a slab-shaped manufactured article M for the purpose of decorating the slab-shaped manufactured article M and/or to display merchandise and/or commercial information on the outer surface of the latter.

With particular reference to the embodiment shown in the figures, the slab-shaped manufactured article M is made of sheet, that is, it is provided with an extremely small thickness with respect to its length and width. In this sense, the slab-shaped manufactured article M can, e.g. consist of a sheet of paper, a metal sheet or a piece of fabric.

This particular descriptive choice should not be seen as limiting but merely explanatory of a possible use of the printer 1.

In this regard, it is worth noting that alternative embodiments of the printer 1 may be provided wherein the slab-shaped manufactured article M has different conformation and, e.g., greater thickness than a sheet element.

The slab-shaped manufactured article M comprises a printable surface on which the printing fluid is dispensed through the printer 1.

The printer 1 comprises at least one base frame 2 for resting on the ground.

With particular reference to the embodiment shown in the figures, the base frame 2 comprises a plurality of supporting elements 3 on the ground and a plurality of containment walls 4, associated with the supporting elements 3 and defining a printing chamber 5 together with the latter.

The printing chamber 5 is provided with an inlet port 6 of the slab-shaped manufactured article M to be printed and with an outlet port 7 of the slab-shaped manufactured article M to be printed.

The printer 1 comprises at least one line of forward movement 8 associated with the base frame 2 and adapted to move the slab-shaped manufactured article M along a substantially horizontal direction of forward movement 9.

The direction of forward movement 9 runs from the inlet port 6 to the outlet port 7.

In actual facts, the line of forward movement 8 moves the slab-shaped manufactured article M towards the inlet port 6, within the printing chamber 5 and out of the latter through the outlet port 7.

Conveniently, the line of forward movement 8 is partly arranged within the printing chamber 5.

With particular reference to the embodiment shown in the figures, the line of forward movement 8 comprises a conveyor belt defining a substantially horizontal supporting plane of the slab-shaped manufactured article M.

When the slab-shaped manufactured article M is arranged on the line of forward movement 8, the printable surface is arranged substantially horizontally and faces upwards. The printer 1 comprises at least one printing head 10 associated with the base frame 2.

The printing head 10 is arranged within the printing chamber 5.

The printing head 10 comprises at least one base structure 11 arranged on top of the line of forward movement 8.

In detail, the printing head 10 comprises a base framework 12 associated with the base frame 2 and comprising the base structure 11.

With particular reference to the embodiment shown in the figures, the base structure 11 has a substantially flat conformation and is arranged substantially horizontally. Specifically, the base structure 11 comprises a first transverse side I la and a second transverse side 11b and a pair of longitudinal sides 11c.

The printing head 10 comprises a plurality of printheads 13 associated with the base structure 11 and adapted to dispense the printing fluid onto the slab-shaped manufactured article M.

Precisely, each printhead 13 comprises a plurality of downward-facing dispensing nozzles adapted to dispense the printing fluid onto the printable surface of the slabshaped manufactured article M.

Conveniently, the printer 1 comprises movement means 14a, 14b associated with the base frame 2 and adapted to move the printing head 10 in a sliding manner with respect to the line of forward movement 8 along a direction of shifting 15 substantially horizontal and substantially orthogonal to the direction of forward movement 9.

With special reference to the particular embodiment shown in the figures, the first transverse side I la and the second transverse side 11b are substantially orthogonal to the direction of shifting 15.

With special reference to the particular embodiment shown in the figures, the slabshaped manufactured article M is moved from the line of forward movement 8 as far as it is arranged in the proximity of the printing head 10.

At this point, the line of forward movement 8 is stopped and the printing head 10 is made to slide along the direction of shifting 15, positioning it on the line of forward movement 8 and, consequently, on the slab-shaped manufactured article M.

In this way, the printing head 10 is arranged on the slab-shaped manufactured article M during the dispensing of the printing fluid.

The movement means 14a, 14b comprise at least one sliding guide 14a, running along the direction of shifting 15, and one carriage 14b, associated with the sliding guide 14a in a sliding manner along the direction of shifting 15.

The sliding guide 14a is arranged on top of the line of forward movement 8.

The base framework 12 is mounted on the carriage 14b and is movable locked together with the latter while sliding along the direction of shifting 15.

Alternative embodiments of the printer 1 wherein the printing head 10 is stationary with respect to the base frame 2 and positioned on top of the line of forward movement 8 cannot however be ruled out.

In this particular embodiment, the dispensing of the printing fluid takes place during the forward movement of the slab-shaped manufactured article M along the direction of forward movement 9.

In actual facts, in this particular embodiment, the line of forward movement 8 is not blocked during the dispensing of the printing fluid.

In order to improve the dispensing of the printing fluid from the printheads 13 and to make of good quality the achievable decoration on the printable surface of the slab-shaped manufactured article M, it is preferred to place the printing head 10 very close to the printable surface.

In detail, the printheads 13 and their respective dispensing nozzles are positioned at a very small and predetermined distance from the printable surface of the slab-shaped manufactured article M during the mutual movement of the printing head 10 and of the slab-shaped manufactured article M.

The printing head 10 comprises anti-crash means 16 associated with the base structure 11 and adapted to detect the crash of the printing head 10 with the slabshaped manufactured article M and to activate an emergency configuration of the printer 1.

The slab-shaped manufactured article M may have portions protruding from the printable surface that raise upwards therefrom.

Such protruding portions may be generated during the movement of the slab-shaped manufactured article M towards the printing head 10 or may result from previous work operations carried out on the slab-shaped manufactured article M. The protruding portions may, e.g., consist of, glue drops or dirt, or they may consist of one or more folds of the slab-shaped manufactured article M.

In particular, in the case where the slab-shaped manufactured article M consists of a sheet of metal, the protruding portions may consist of the folds that may be created, for example, at the edges.

In the context of this disclosure, the crash of the printing head 10 with the slabshaped manufactured article M should be meant as the crash of the printing head 10 with a protruding portion of the slab-shaped manufactured article M of the type just described.

In this regard, it is worth mentioning how the predetermined distance at which the slab-shaped manufactured article M and the printing head 10 are maintained during mutual movement does not take such protrusions into account.

The anti-crash means 16 are adapted to detect such protrusions in order to safeguard all components of the printing head 10 and, in particular, the dispensing nozzles which are known to be particularly delicate.

The emergency configuration wherein the printer 1 is placed as a result of the detection of a crash may result, e.g., in the issuance of an audible and/or visual alarm and/or the blocking of the mutual movement between the printing head 10 and the slab-shaped manufactured article M.

In the particular embodiment shown in the figures, the emergency configuration involves blocking the mutual movement between the printing head 10 and the slabshaped manufactured article M.

Specifically, according to the preferred embodiment shown in the figures, the emergency configuration involves blocking the shifting of the printing head 10 along the direction of shifting 15.

According to the invention, the anti-crash means 16 comprise at least one slabshaped element 17 associated inferiorly with the base structure 11 and in a removable manner between at least a first position, wherein it is lowered and spaced apart from the base structure 11, and a second position, wherein it is raised and placed in contact with the base structure 11 as a result of the crash of the printing head 10 with the slab-shaped manufactured article M.

The slab-shaped element 17 comprises a plurality of housing openings 18 wherein the printheads 13 are at least partly inserted.

Specifically, the slab-shaped element 17 directly crashes with the slab-shaped manufactured article M if there is a protruding portion and raises by contacting the base structure 11.

The anti-crash means 16 according to the invention detect the positioning of the slabshaped element 17 in the second position and activate the emergency configuration of the printer 1.

The slab-shaped element 17 according to the invention preserves the printheads 13 since any protruding portions on the slab-shaped manufactured article M contact the slab-shaped element 17 without crashing with the printheads 13.

In addition, the slab-shaped element 17 also allows the detection of any protruding portions that may originate when the slab-shaped manufactured article M is already placed under the printheads 13.

Again, the special technical device of providing the slab-shaped element 17 with housing openings 18 enables the dispensing of the printing fluid from the printheads 13.

Preferably, each printhead 13 is placed where a respective housing opening 18 is located.

With special reference to the particular embodiment shown in the figures, the anticrash means 16 comprise at least one holding element 19a, 19b attached to the slabshaped element 17 and resting on the base structure 11.

The slab-shaped element 17 is suspended from the base structure 11 by interposition of the holding element 19a, 19b and kept in the first position by gravity.

In detail, the holding element 19a, 19b comprises at least one central pivot 19a, attached to the slab-shaped element 17, and at least one substantially hollow spacer body 19b, arranged around the central pivot 19a and resting on the base structure 11. Alternative embodiments of the printer 1 cannot however be ruled out wherein the anti-crash means 16 may be of a different type and, e.g., comprise an elastic connecting element positioned between the slab-shaped element 17 and the base structure 11 and adapted to keep the slab-shaped element 17 in the first position.

In this particular embodiment, the slab-shaped element 17, when crashing with a protruding portion of the slab-shaped manufactured article M, raises by compressing the elastic connecting element.

With special reference to the particular embodiment shown in the figures, it can be seen that the anti-crash means 16 comprise a plurality of holding elements 19a, 19b. Precisely, the anti-crash means 16 comprise a first row of holding elements 19a, 19b arranged at the first transverse side 11 a, a second row of holding elements 19a, 19b arranged at the second transverse side 11b and a third row of holding elements 19a, 19b arranged at a median plane of the slab-shaped element 17 and running substantially parallel to the first row and to the second row.

Advantageously, the slab-shaped element 17 comprises: at least one plate-shaped portion 20 arranged substantially horizontally and on which the housing openings 18 are formed; at least one spacer bar 21, 22 located between the plate-shaped portion 20 and the base structure 11 and developing substantially horizontally.

The spacer bar 21, 22 is placed in contact with the base structure 11 in the second position.

Preferably, the slab-shaped element 17 comprises at least two lateral spacer bars 21 associated with two opposite edges of the plate-shaped portion 20.

With special reference to the particular embodiment shown in the figures, the lateral spacer bars 21 are associated with the edges of the plate-shaped portion 20 arranged substantially orthogonal to the direction of shifting 15.

In other words, each of the lateral spacer bars 21 is arranged at a respective transverse side I la, 1 lb of the base structure 11.

Advantageously, each of the lateral spacer bars 21 comprises at least one oblique portion 21b facing downwards and outwards of the slab-shaped element 17.

The oblique portion 21b thus directed defines a guiding surface for any protruding portion present on the slab-shaped manufactured article M that wedges under the contacted lateral spacer bar 21 causing the slab-shaped element 17 to raise.

The special positioning of the lateral spacer bars 21 allows the presence of a protruding portion on the slab-shaped manufactured article M to be immediately detected as soon as the shifting of the printing head 10 on the line of forward movement 8 in either way of the direction of shifting 15 is activated.

In the case where the printing head 10 is always positioned above the line of forward movement 8 and the slab-shaped manufactured article M moves along the direction of forward movement 9, conveniently, the lateral spacer bars 21 are associated with two opposite sides of the base structure 11 arranged substantially orthogonal to the direction of forward movement 9.

Conveniently, each of the lateral spacer bars 21 comprises at least one housing recess wherein the plate-shaped portion 20 is arranged at least partly.

Advantageously, the slab-shaped element 17 comprises at least one central spacer bar 22 arranged along a median plane of the plate-shaped portion 20 and substantially parallel to the lateral spacer bars 21.

The first row of holding elements 19a, 19b is arranged at one of the lateral spacer bars 21, the second row of holding elements 19a, 19b is arranged at the other lateral spacer bar 21 and the third row is arranged at the central spacer bar 22.

Advantageously, the anti-crash means 16 comprise electrification means 23 of the base structure 11 and of the slab-shaped element 17.

The base structure 11 and the slab-shaped element 17 are electrically insulated in the first position and are electrically connected in the second position.

Conveniently, the spacer body 19b is made of electrically insulating material. Advantageously, the base structure 11 and the slab-shaped element 17 are made of an electrically conductive material.

Preferably, the electrification means 23 comprise at least one pair of conductor elements connected to an external source of electrification and associated with the base structure 11 and with at least one of the central pivots 19a, respectively.

Conveniently, the anti-crash means 16 comprise detecting means adapted to detect the passage of electric current between the base structure 11 and the slab-shaped element 17 in the second position.

In other words, when the slab-shaped element 17 is arranged in the second position, the electric circuit consisting of the slab-shaped element 17 and the base structure 11 closes, and the detecting means detect the passage of current within that circuit.

When the detecting means detect the passage of current between the base structure 11 and the slab-shaped element 17, the printer 1 is placed in the emergency configuration.

Conveniently, the printer 1 comprises auxiliary anti-crash means 24 arranged upstream of the printing head 10 along the direction of forward movement 9 and adapted to detect at least one protruding portion of the slab-shaped manufactured article M and to allocate the printer 1 in the emergency configuration.

Preferably, the auxiliary anti-crash means 24 comprise at least one detecting bar 24 arranged on top of the line of forward movement 8, developing substantially horizontally and arranged substantially orthogonal to the direction of forward movement 9.

In detail, the detecting bar 24 is arranged where the inlet port 6 of the printing chamber 5 is located.

With particular reference to the embodiment shown in the figures, the detecting bar 24 is movable between a first configuration, wherein it is placed at a predetermined height from the line of forward movement 8, and a second configuration, wherein it is placed at a greater height from the line of forward movement 8 than the predetermined height.

Specifically, the predetermined height is related to the thickness in the slab-shaped manufactured article M free of protruding portions.

The detecting bar 24 is placed in the second configuration as a result of the action exerted by a protruding portion on the detecting bar 24.

In detail, the detecting bar 24 is raised when it contacts a protruding portion of the slab-shaped manufactured article M.

The auxiliary anti-crash means 24 detect the positioning of the detecting bar 24 in the second configuration and position the printer 1 in the emergency configuration. The operation of the printer 1 according to the invention is as follows.

The slab-shaped manufactured article M is placed on the line of forward movement 8 and made to move forward from the latter towards the inlet port 6.

The slab-shaped manufactured article M, during its movement towards the inlet port 6, is placed where the auxiliary anti-crash means 24 are located.

If the auxiliary anti-crash means 24 detect a protruding portion from the slab-shaped manufactured article M, they position the printer 1 in the emergency configuration. Otherwise, the slab-shaped manufactured article M is moved until it is where the printing head 10 is located.

At this point, the line of forward movement 8 is blocked and the printing head 10 is progressively placed on the line of forward movement 8 thanks to the activation of the movement means 14a, 14b.

If, during such movement, the slab-shaped element 17 contacts a portion protruding from the slab-shaped manufactured article M, the slab-shaped element 17 itself is allocated into the second position and the anti-crash means 16 place the printer 1 in the emergency configuration.

Instead, the dispensing of the printing fluid onto the slab-shaped manufactured article M is continued and, then, the slab-shaped manufactured article M is moved away from the printing head 10 through the activation of the line of forward movement 8. It has in practice been ascertained that the described invention achieves the intended objects.

Specifically, the slab-shaped element that the printer according to the invention is provided with allows detecting the protrusions present on the slab-shaped manufactured article, including those that may form below the printheads when the printing head is positioned on top of the slab-shaped manufactured article.

In addition, the presence of the slab-shaped element positioned between the printheads and the slab-shaped manufactured article protects the dispensing nozzles from any protrusions that directly contact the slab-shaped element.

Therefore, the printer according to the invention allows the occurrence of damage to the dispensing nozzles to be reduced.

At the same time, the printer according to the invention makes it possible to reduce the frequency of the maintenance operations concerning the printing head, especially the dispensing nozzles, and to reduce their costs.

Claims

1) Printer (1) for slab-shaped manufactured articles, comprising: at least one base frame (2) for resting on the ground; at least one line of forward movement (8) associated with said base frame (2) and adapted to move at least one slab-shaped manufactured article (M) along a substantially horizontal direction of forward movement (9); at least one printing head (10) associated with said base frame (2) and comprising: at least one base structure (11) arranged on top of said line of forward movement (8); a plurality of printheads (13) associated with said base structure (11) and adapted to dispense at least one printing fluid onto said slab-shaped manufactured article (M); and anti-crash means (16) associated with said base structure (11) and adapted to detect the crash of said printing head (10) with said slab-shaped manufactured article (M) and to activate an emergency configuration of said printer (1); characterized by the fact that said anti-crash means (16) comprise at least one slabshaped element (17) associated inferiorly with said base structure (11) and in a removable manner between at least a first position, wherein it is lowered and spaced apart from said base structure (11), and a second position wherein it is raised and placed in contact with said base structure (11) as a result of the crash of said printing head (10) with said slab-shaped manufactured article (M), said slab-shaped element (17) comprising a plurality of housing openings (18) wherein said printheads (13) are at least partly inserted.

2) Printer (1) according to claim 1, characterized by the fact that said anti-crash means (16) comprise at least one holding element (19a, 19b) attached to said slabshaped element (17) and resting on said base structure (11), said slab-shaped element (17) being suspended from said base structure (11) by interposition of said holding element (19a, 19b) and kept in said first position by gravity.

3) Printer (1) according to claim 2, characterized by the fact that said holding element (19a, 19b) comprises at least one central pivot (19a), attached to said slab- shaped element (17), and at least one substantially hollow spacer body (19b) arranged around said central pivot (19a) and resting on said base structure (11).

4) Printer (1) according to one or more of the preceding claims, characterized by the fact that said slab-shaped element (17) comprises: at least one plate-shaped portion (20) arranged substantially horizontally and on which said housing openings (18) are formed; at least one spacer bar (21, 22) located between said plate-shaped portion (20) and said base structure (11) and developing substantially horizontally, said spacer bar (21, 22) being placed in contact with said base structure (11) in said second position.

5) Printer (1) according to claim 4, characterized by the fact that said slab-shaped element (17) comprises at least two lateral spacer bars (21), associated with two opposite edges of said plate-shaped portion (20).

6) Printer (1) according to one or more of the preceding claims, characterized by the fact that each of said lateral spacer bars (21) comprises at least one oblique portion (21b) facing downwards and outwards of said slab-shaped element (17).

7) Printer (1) according to one or more of the preceding claims, characterized by the fact that said anti-crash means (16) comprise electrification means (23) of said base structure (11) and of said slab-shaped element (17), said base structure (11) and said slab-shaped element (17) being electrically insulated in said first position and being electrically connected in said second position.

8) Printer (1) according to claim 7, characterized by the fact that said spacer body (19b) is made of an electrically insulating material and by the fact that said base structure (11) and said slab-shaped element (17) are made of an electrically conductive material.

9) Printer (1) according to claim 7 and 8, characterized by the fact that said anticrash means (16) comprise detecting means adapted to detect the passage of electric current between said base structure (11) and said slab-shaped element (17) in said second position.

10) Printer (1) according to one or more of the preceding claims, characterized by the fact that it comprises movement means (14a, 14b) associated with said base frame (2) and adapted to move said printing head (10) in a sliding manner with respect to said line of forward movement (8) along a direction of shifting (15) substantially horizontal and substantially orthogonal to said direction of forward movement (9).