Print apparatus may be used to print representations, such as text or images, onto print substrates. Print apparatus may include a print head to apply print agent to a print substrate. Print quality may be affected by air currents between the print head and the print substrate during printing.
Various examples will be described below with reference to the following figures, wherein:
Air currents between the print head 4 and the platen 2 may be generated when the print head 4 applies print agent to the print substrate 3. In particular, unsteady air flow (for example, turbulent air flow) between the print head 4 and the platen 2 may be caused by displacement of air between the print head 4 and the platen 2 as print agent is ejected from the print head 4. Unsteady air flow between the print head 4 and the platen 2 may result in inaccurate placement of print agent on the print substrate 3, potentially leading to a reduction in print quality. Actively drawing air from between the print head 4 and the platen 2 and into the inlet 6, however, may establish a steady air flow between the print head 4 and the platen 2, for example by reducing turbulence or causing a laminar flow, and thereby improving print quality.
The effectiveness of the steadying of the air flow may depend on the clearance C between the inlet 6 and the platen 2 as air is drawn into the inlet 6. For example, when the clearance C is relatively large (for example, greater than about 4 mm), more of the air drawn into the inlet 6 may flow from outside a printing zone (i.e. from outside the region between the print head 4 and the platen 2) than from within the printing zone. However, when the clearance C is relatively small (for example, no greater than about 4 mm), more of the air drawn into the inlet may flow from within the printing zone (i.e. from between the print head 4 and the platen 2) than from outside the printing zone. There may, therefore, be more effective steadying of the air flow (e.g. increased laminar flow or reduced turbulence) between the print head 4 and the platen 2 when the clearance C is relatively small. The suction device 5 may use less power to achieve a predetermined level of air flow steadying between the print head 4 and the platen 2 when the clearance C is relatively small in comparison to when the clearance C is relatively large.
Movements of the print head 4 may be controlled with a high level of precision, for example to enable precise control of the application of print agent to the print substrate 3. Accordingly, since the inlet 6 is movable with the print head 4 to vary the clearance C, the clearance C may also be set with a high level of precision. The print apparatus 1 may therefore enable precise targeting of a predetermined clearance C in order that more air is drawn into the inlet from within the printing zone than from outside the printing zone, thereby reducing the suction power used to achieve a predetermined level of steadying in the air flow between the print head 4 and the platen 2. This may be achieved without manufacturing the suction device 5 or any of its components to precise tolerances and/or without precisely controlling the position of the suction device 5 or any of its components within the print apparatus 1 (other than through movement of the print head 4).
The print apparatus 1 may comprise a component support structure such as a housing. The suction device 5 and the print head 4 may be separately mounted to the component support structure. That is to say, the suction device 5 and the print head 4 may be mounted to the component support structure independently of one another. The suction device 5 and the print head 4 may therefore be movable independently of one another.
In some examples, the inlet 6 is coupled to the print head 4 (as indicated by the dashed line connecting the inlet 6 to the print head 4 in
In some examples, the inlet 6 is an open end of a nozzle, the suction device 5 being to draw air from between the print head 4 and the platen 2 through the nozzle. In some examples, movement of the print head 4 causes movement of the nozzle.
In some examples, the nozzle is coupled to the print head 4 such that the open end of the nozzle is movable with the print head 4 to vary the clearance C. In some examples, the nozzle is attached to, or forms part of, the print head 4 (or the print head assembly comprising the print head 4) such that the open end of the nozzle is movable with the print head 4 to vary the clearance C.
In some examples, the nozzle and the print head 4 are independent components of the print apparatus 1, although movement of the open end of the nozzle towards the platen 2 is coupled to (e.g. caused by) movement of the print head 4 towards the platen 2. For example, it may be that the nozzle is not located on (i.e., is not attached to and does not form park of) the print head 4 (or the print head assembly), In some examples, the open end of the nozzle is movable towards the platen 2 by engagement of the print head 4 (or the print head assembly) with a portion of the nozzle. For example, the nozzle may be arranged (e.g. positioned) such that engagement of the print head 4 (or the print head assembly) with a portion of the nozzle causes movement of the open end of the nozzle towards the platen 2.
For example,
As further illustrated in
The print head assembly 18 may be a laterally stationary print head assembly. It may be that the laterally stationary print head assembly 18 does not move laterally (i.e. in a plane parallel to the platen 12 and/or the print substrate) during printing, although the laterally stationary print head assembly 18 is movable in a direction perpendicular to the platen 12. Alternatively, it may be that lateral movement of the laterally stationary print head assembly 18 is restricted during printing. For example, it may be that any lateral movement of the laterally stationary print head assembly 18 (i.e. the distance moved by the print head assembly 18 in a lateral direction) during printing is small in comparison to any movement of the laterally stationary print head assembly 18 in a direction perpendicular to the platen 12 (i.e. the distance moved by the print head assembly 18 in the perpendicular direction). In some examples, the print head assembly 18 is a substrate-wide print head assembly comprising a plurality of laterally stationery print heads supported by a substrate-wide print bar (sometimes known as a ‘page wide array’ (PWA) print apparatus). In some examples, small lateral movements of the (i.e. entire) substrate-wide print bar are possible, although lateral movement of the individual laterally stationery print heads relative to one another may be restricted or prevented.
In the example shown in
The nozzle 17 may be formed from a resilient polymeric material. The nozzle 17 may be manufactured by injection moulding, i.e. the nozzle 17 may be an injection-moulded nozzle 17.
The print apparatus 10 may comprise a component support structure such as a housing. The suction device 15 and the print head 14 and/or the print head assembly 18 may be separately mounted to the component support structure. That is to say, the suction device 15 and the print head 14 and/or the print head assembly 18 may be mounted to the component support structure independently of one another. The suction device 15 and the print head 14 and/or the print head assembly 18 may therefore be movable independently of one another.
As further illustrated in
The print head assembly 28 may be a laterally stationary print head assembly. It may be that the laterally stationary print head assembly 28 does not move laterally (i.e. in a plane parallel to the platen 22 and/or the print substrate) during printing, although the laterally stationary print head assembly 28 is movable in a direction perpendicular to the platen 22. Alternatively, it may be that lateral movement of the laterally stationary print head assembly 28 is restricted during printing. For example, it may be that any lateral movement of the laterally stationary print head assembly 28 (i.e. the distance moved by the print head assembly 28 in a lateral direction) during printing is small in comparison to any movement of the laterally stationary print head assembly 28 in a direction perpendicular to the platen 22 (i.e. the distance moved by the print head assembly 18 in the perpendicular direction). In some examples, the print head assembly 28 is a substrate-wide print head assembly comprising a plurality of laterally stationery print heads supported by a substrate-wide print bar (sometimes known as a ‘page wide array’ (PWA) print apparatus). In some examples, small lateral movements of the (i.e. entire) substrate-wide print bar are possible, although lateral movement of the individual laterally stationery print heads relative to one another may be restricted or prevented.
In the example shown in
The nozzle 27 may be formed from a resilient polymeric material. The nozzle 27 may be manufactured by injection moulding, i.e. the nozzle 27 may be an injection-moulded nozzle 27.
The print apparatus 20 may comprise a component support structure such as a housing. The suction device 25 and the print head 24 and/or the print head assembly 28 may be separately mounted to the component support structure. That is to say, the suction device 25 and the print head 24 and/or the print head assembly 28 may be mounted to the component support structure independently of one another. The suction device 25 and the print head 24 and/or the print head assembly 28 may, therefore, be movable independently of one another.
The print head assembly 38 may comprise a print head to apply print agent to the print substrate. For example, the print head assembly 38 may comprise a print head support (such as a print bar) to which the print head is attached. The print head assembly 38 may comprise a plurality of print heads attached to the print head support (e.g. the print bar).
The print apparatus 30 may comprise a component support structure such as a housing. The suction device 35 and the print head assembly 38 may be separately mounted to the component support structure. That is to say, the suction device 35 and the print head assembly 38 may be mounted to the component support structure independently of one another.
The open end 36 of the nozzle 37 may be biased away from the platen 32 but movable towards the platen 32 against the bias by engagement of the portion of the print head assembly 38 with the portion of the nozzle 37. For example, the nozzle 37 may be hinged to permit pivoting movement of the open end 36 of the nozzle 37 towards the platen 32 by engagement of the portion of the print head assembly 38 with the portion of the nozzle 37.
The nozzle 37 may comprise a distal portion defining the open end 36 and a proximal portion attached to the suction device 35. The distal portion may be hingedly attached to the proximal portion at a hinge such that the distal portion is pivotable relative to the proximal portion about the hinge. For example, as illustrated schematically in
As illustrated schematically in
The nozzle 37 may be formed from a resilient polymeric material. For example, it may be that the nozzle wall 40 (i.e. including any region 41 having a reduced thickness) is formed from a resilient polymeric material. The nozzle 37 may be manufactured by injection moulding, i.e. the nozzle 37 may be an injection-moulded nozzle 37.
It may be that the open end 36 is movable towards the platen 32 by engagement of the portion of the print head assembly 38 with a surface of the nozzle 37. The surface of the nozzle 37 may be an upper surface (e.g. an uppermost surface) of the nozzle 37. The surface of the nozzle 37 which is engaged by the portion of the print head assembly 38 may have a profile defined by a plurality of protrusions. The protrusions may be elongate ribs. The profile may be further defined by a plurality of recesses between the protrusions. In examples in which the protrusions are elongate ribs, the recesses may be elongate grooves. The protrusions may be arranged in a repeating pattern (i.e. a periodic array). Each protrusion may have a height (i.e., in a direction locally perpendicular to a profile of the nozzle 37) of at least about 0.5 mm, for example at least about 1 mm, for example from about 0.5 mm to about 2 mm. Accordingly, each recess ma have a depth (i.e., in a direction locally perpendicular to a profile of the nozzle 37) of at least about 0.5 mm, for example at least about 1 mm, for example from about 0.5 mm to about 2 mm. The protrusions and/or recesses may extend up to a distal-most tip of the nozzle 37.
The print head assembly 38 may be a laterally stationary print head assembly. It may be that the laterally stationary print head assembly 38 does not move laterally (i.e. in a plane parallel to the platen 32 and/or the print substrate) during printing, although the laterally stationary print head assembly 38 is movable in a direction perpendicular to the platen 32. Alternatively, it may be that lateral movement of the laterally stationary print head assembly 38 is restricted during printing. For example, it may be that any lateral movement of the laterally stationary print head assembly 38 (i.e. the distance moved by the print head assembly 38 in a lateral direction) during printing is small in comparison to any movement of the laterally stationary print head assembly 38 in a direction perpendicular to the platen 32 (i.e. the distance moved by the print head assembly 38 in the perpendicular direction). In some examples, the print head assembly 38 is a substrate-wide print head assembly comprising a plurality of laterally stationery print heads supported by a substrate-wide print bar (sometimes known as a ‘page wide array’ (PWA) print apparatus), In some examples, small lateral movements of the (i.e. entire) substrate-wide print bar are possible, although lateral movement of the individual laterally stationery print heads relative to one another may be restricted or prevented.
In some examples, a method (as illustrated schematically in
The method may comprise: moving the open end 36 of the nozzle 37 towards the platen 32 until a clearance between the open end 36 and the platen is no greater than about 4 mm, for example, no greater than about 3 mm, or no greater than about 2 mm. The method may comprise: moving the open end 36 of the nozzle 37 towards the platen 32 until the clearance between the open end 36 and the platen is from about 1 mm to about 4 mm, for example, from about 1 mm to about 3 mm, or from about 1 mm to about 2 mm, or from about 2 mm to about 3 mm. A minimum clearance of about 1 mm, for example, about 2 mm, may enable unimpeded passage of print substrate between the print head assembly 38 and the platen 32.
As illustrated schematically in
The width of the platen may be at least about 10 inches (i.e. about 25 cm), for example, at least about 20 inches (i.e. about 51 cm), or at least about 30 inches (i.e. about 76 cm), or at least about 40 inches (i.e. about 102 cm).
One example nozzle 56A is shown in more detail in
However, the presence of the elongate ribs 62 is optional. For example, nozzles may not be provided with protrusions such as ribs in examples in which the surface of the portion of the print head assembly which engages the nozzles is uniform (e.g. in examples in which the portion of the print head assembly which engages the nozzles does not have a recess). In such examples, the surface of the print head assembly and the top surfaces of the nozzles may be flush with one another on engagement.
It will be understood that various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of features described herein.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/067817 | 12/20/2019 | WO |