WO2022229602A1 - Cleaning head for inkjet printing apparatus - Google Patents
Cleaning head for inkjet printing apparatus Download PDFInfo
- Publication number
- WO2022229602A1 WO2022229602A1 PCT/GB2022/050992 GB2022050992W WO2022229602A1 WO 2022229602 A1 WO2022229602 A1 WO 2022229602A1 GB 2022050992 W GB2022050992 W GB 2022050992W WO 2022229602 A1 WO2022229602 A1 WO 2022229602A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- nozzle
- cleaning head
- tapered
- head according
- opposed
- Prior art date
Links
- 238000004140 cleaning Methods 0.000 title claims abstract description 120
- 238000007641 inkjet printing Methods 0.000 title claims description 26
- 238000007639 printing Methods 0.000 claims description 24
- 238000012423 maintenance Methods 0.000 claims description 13
- 230000000541 pulsatile effect Effects 0.000 claims description 3
- 238000004891 communication Methods 0.000 claims description 2
- 239000000976 ink Substances 0.000 description 34
- 238000010926 purge Methods 0.000 description 11
- 239000003570 air Substances 0.000 description 7
- 239000012530 fluid Substances 0.000 description 6
- 239000002699 waste material Substances 0.000 description 5
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000010146 3D printing Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 2
- 238000011010 flushing procedure Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000001154 acute effect Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000001723 curing Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000003847 radiation curing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/135—Nozzles
- B41J2/165—Prevention or detection of nozzle clogging, e.g. cleaning, capping or moistening for nozzles
- B41J2/16517—Cleaning of print head nozzles
- B41J2/1652—Cleaning of print head nozzles by driving a fluid through the nozzles to the outside thereof, e.g. by applying pressure to the inside or vacuum at the outside of the print head
- B41J2/16532—Cleaning of print head nozzles by driving a fluid through the nozzles to the outside thereof, e.g. by applying pressure to the inside or vacuum at the outside of the print head by applying vacuum only
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/135—Nozzles
- B41J2/165—Prevention or detection of nozzle clogging, e.g. cleaning, capping or moistening for nozzles
- B41J2/16585—Prevention or detection of nozzle clogging, e.g. cleaning, capping or moistening for nozzles for paper-width or non-reciprocating print heads
- B41J2/16588—Print heads movable towards the cleaning unit
Definitions
- the present invention relates to a cleaning head for inkjet printing apparatus, particularly but not exclusively inkjet printing apparatus of the type having a printhead assembly within which there is provided a plurality of printing heads.
- Each printing head includes a nozzle plate on which there is defined an exterior nozzle orifice surface having a row of nozzle orifices through which ink is ejected under a microprocessor control.
- inkjet printing apparatus of the present type require regular maintenance and cleaning.
- droplets of ink become airborne as they are ejected and can adhere to the nozzle surface adjacent to and within the nozzle orifices.
- the build-up of ink and debris subsequently affects the ink injection performance to the extent that print quality reduces.
- the present invention is particularly directed to cleaning effectively the orifices and orifice surfaces of a nozzle plate without causing physical wear to the orifice surface while effecting efficient cleaning and reducing the need for additional maintenance. It will be understood by the skilled addressee that the terms ‘printing head’ and
- the term ‘wiping’ as applied to cleaning a surface with an elastomeric blade or with a material mop, has been used synonymously with ‘scraping’ which often implies the use of a rigid edge, however, is also used more broadly to describe the action of an ‘air-knife’ where a narrow blade of high velocity air is angularly directed onto a surface to remove debris therefrom.
- the term ‘scrape’ is also used to denote an action where high shear forces are brought to bear against a surface with the intended purpose of removing ink and/or debris from the subject surface.
- ink may comprise water-based inks, solvent based inks and inks having specialised characteristics relating to curing, such as ultraviolet UV radiation curing inks, and related to security features, most commonly, radiating under UV light.
- a cleaning head for cleaning an exposed exterior nozzle orifice surface of a nozzle plate of an inkjet print head, the cleaning head comprising: a body defining a vacuum port configured to be coupled to a vacuum source, the body having an exterior surface profiled to deflect the trajectory of air drawn into the vacuum port against the exposed exterior nozzle orifice surface of the nozzle plate as the nozzle plate moves relative to the cleaning head along a path substantially parallel to a longitudinal axis of the body so as to dislodge ink and accumulated debris from the exposed exterior nozzle orifice surface, said ink and debris dislodged from the orifice surface being drawn into the vacuum port (e.g. for collection in a fluid trap for disposal); wherein the body comprises: a nozzle portion; and a base portion supporting the nozzle portion.
- the vacuum port comprises an inlet slot (e.g. horizontal inlet slot) extending laterally between opposed first and second laterally spaced side walls of the nozzle portion.
- inlet slot e.g. horizontal inlet slot
- the nozzle portion defines: a tapered nozzle body defining an external airflow guide surface; and a nozzle tip surrounding the inlet slot.
- the nozzle tip is a tapered nozzle tip.
- the tapered nozzle body has an uppermost tapered section inclined to vertical at a steeper taper angle than a corresponding taper angle of a lowermost tapered section of the tapered nozzle tip.
- a cleaning head in which a nozzle with an inlet slot and an airflow guide surface is combined with an inclined droplet collection surface configured to both guide airflow towards the nozzle orifice surface and collect droplets attempting to travel down the sides of the nozzle.
- the proposed nozzle geometry has been found to allow a reduction in area of the inlet slot and increase in vacuum flow rate resulting in more effective cleaning and reduced cleaning head maintenance.
- the cleaning head is a contactless cleaning head (i.e. no part of the cleaning head makes physical contact with the inkjet printing head).
- the body comprises first and second opposed inclined end walls
- the body comprises first and second opposed inclined side walls.
- the uppermost tapered section of the tapered nozzle body has a taper angle (e.g. mean taper angle) A.
- the lowermost tapered section of the tapered nozzle tip has a taper angle (e.g. mean taper angle) B.
- the or each taper angle is an acute angle, measured from vertical (i.e. the smaller the value of the angle, the steeper the inclination of the taper).
- a ⁇ B i.e. taper angle A is steeper than taper angle B.
- the tapered nozzle tip has a substantially constant taper angle (e.g. a constant taper angle B).
- taper angle A 25-37°.
- taper angle B is substantially 49°.
- the tapered nozzle body comprises first and second opposed nozzle body end walls.
- the tapered nozzle body comprises first and second opposed nozzle body side walls.
- one or more (e.g. both) of the first and second opposed nozzle body end walls are inclined relative to vertical.
- one or more (e.g. both) of the first and second opposed nozzle body side walls are inclined relative to vertical.
- the nozzle tip comprises first and second opposed nozzle tip end walls.
- the nozzle tip comprises first and second opposed nozzle tip side walls.
- one or more (e.g. both) of the first and second opposed nozzle tip end walls are inclined relative to vertical.
- one or more (e.g. both) of the first and second opposed nozzle tip side walls are inclined relative to vertical. In one embodiment, one or more (e.g. both) of the first and second opposed nozzle body end walls have an uppermost tapered section inclined by a first taper angle (e.g. first mean taper angle) Ai.
- first taper angle e.g. first mean taper angle
- taper angle Ai 25-37°.
- taper angle Ai is substantially 31°.
- one or more (e.g. both) of the first and second opposed nozzle body side walls have an uppermost tapered section inclined by a second taper angle (e.g. second mean taper angle) A2.
- Ai A2.
- taper angle A2 17-25°. In one embodiment, taper angle A2 is substantially 21°.
- one or more (e.g. both) of the first and second opposed nozzle tip end walls are inclined by a first taper angle (e.g. first mean taper angle) Bi.
- taper angle Bi 39-59°.
- taper angle Bi is substantially 49°.
- one or more (e.g. both) of the first and second opposed nozzle tip side walls are inclined by a second taper angle (e.g. second mean taper angle) B2.
- taper angle B2 27-41°.
- taper angle B2 is substantially 34°.
- the uppermost tapered section of the tapered nozzle body is contiguous with the lowermost tapered section of the tapered nozzle tip.
- the tapered nozzle body and the tapered nozzle tip are formed as a single component.
- one or more (e.g. both) of the first and second opposed nozzle body side walls have a concave curved surface profile (e.g. with an angle of inclination to vertical which increases with increase distance from the bottom of the base portion).
- one or more (e.g. both) of the first and second opposed nozzle body end walls have a concave curved surface profile (e.g. with an angle of inclination to vertical which increases with increase distance from the bottom of the base portion).
- one or more (e.g. both) of the first and second opposed nozzle tip side walls have a concave curved surface profile (e.g. with an angle of inclination to vertical which increases with increase distance from the bottom of the base portion). In one embodiment, one or more (e.g. both) of the first and second opposed nozzle tip end walls have a concave curved surface profile (e.g. with an angle of inclination to vertical which increases with increase distance from the bottom of the base portion).
- the nozzle portion defines a passageway defining a tapered internal chamber section and an elongate entrance section connecting the inlet slot to the tapered internal chamber section.
- the base portion defines a vacuum source connection chamber and the tapered internal chamber section connects the elongate entrance section to the vacuum source connection chamber.
- the tapered internal chamber section is profiled to act as an internal airflow guide surface (e.g. to smoothly transition airflow passing from the elongate entrance section to the vacuum source connection chamber).
- the internal tapered chamber section comprises first and second opposed internal end walls.
- the internal tapered chamber section comprises first and second opposed internal side walls.
- one or more (e.g. both) of the first and second opposed internal end walls have a convex curved surface profile (e.g. with an angle of inclination to vertical which increases with increased distance from the bottom of the base portion).
- one or more (e.g. both) of the first and second internal side walls have a convex curved surface profile (e.g. with an angle of inclination to vertical which increases with increased distance from the bottom of the base portion).
- the inlet slot has a slot length S L (e.g. extending in the lateral direction) and a slot width Sw (e.g. extending in the longitudinal direction). In one embodiment, the ratio of the slot length S L to the slot width Sw is > 20 (e.g. 20- 30).
- the slot length S L is substantially 27x slot width Sw.
- the print head nozzle plate has an exposed exterior nozzle orifice surface width Pw and the slot length S L is greater than or substantially equal to Pw (e.g. substantially equal to Pw) .
- the inlet slot has a cross-sectional area SA ⁇ 2.6 mm 2 (e.g. ⁇ 2.0 mm 2 , e.g. ⁇ 1.8 mm 2 ).
- an inkjet printing apparatus having a printhead assembly, movable between a printing position and a maintenance position, comprising a plurality of printing heads each of the type having a nozzle plate on which there is defined an exposed exterior nozzle orifice surface, the orifice surface being formed with a row of nozzle orifices through which ink is ejected under microprocessor control; wherein the printing apparatus includes, at the maintenance position of the printhead assembly, a cleaning station comprising a plurality of laterally spaced cleaning heads (e.g.
- each cleaning head is a cleaning head in accordance with the first aspect of the present invention (e.g. in accordance with any embodiment of the first aspect of the present invention).
- the inlet slot has a vacuum flow rate (Fs) >13 litres/min (e.g. >20 litres/min, e.g. substantially 26 litres/min).
- spacing between an uppermost surface of the cleaning head and the exposed exterior nozzle orifice surface of the nozzle plate is in the range of 0.145mm - 0.435mm (e.g. 0.18mm - 0.27mm, e.g. substantially 0.225mm).
- the at least one vacuum source is a non-pulsatile vacuum pump.
- the at least one vacuum source is a constant-velocity vacuum pump (e.g. positive displacement pump or momentum transfer pump).
- the at least one vacuum source is a rotary vane vacuum pump. In one embodiment, the at least one vacuum source has a vacuum source inlet flow rate
- the inkjet printing apparatus includes a plurality of vacuum sources (e.g. as previously defined) and each of the plurality of cleaning heads is connected to a respective one of the plurality of vacuum sources.
- Figure 1A is a schematic perspective view of inkjet printing apparatus in accordance with an embodiment of the present invention including a printhead assembly and a cleaning station with the printhead assembly shown in a printing position;
- Figure IB is a schematic perspective view of the inkjet printing apparatus of Figure 1 A with the printhead assembly shown in a maintenance position;
- Figure 2A is a schematic side view of the cleaning station and printhead assembly of the inkjet printing apparatus of Figure 1 A when the printhead assembly is in the maintenance position;
- Figure 2B is a schematic partial perspective underside view of the printhead assembly and cleaning station of Figure 2A;
- Figure 2C is a schematic diagram illustrating a fluid circuit of the cleaning station of the inkjet printing apparatus of Figure 1A;
- Figure 3 is a schematic perspective view of components of the cleaning station of Figure 1A;
- Figure 4A is a schematic perspective view of a cleaning head of the cleaning station of Figure 1A;
- Figure 4B is a schematic plan view of the cleaning head of Figure 4A;
- Figure 4C is a schematic cross-sectional view of the cleaning head of Figure 4A along line A-A showing external angles and internal geometry thereof;
- Figure 4D is a schematic cross-sectional view of the cleaning head of Figure 4A along line B-B showing external angles and internal geometry thereof
- Figure 4E is a schematic cross-sectional view of the cleaning head of Figure 4A along line A-A showing external dimensions thereof;
- Figure 4F is a schematic cross-sectional view of the cleaning head of Figure 4A along line B-B showing external dimensions thereof;
- Figure 4G is a schematic cross-sectional view of the cleaning head of Figure 4A along line A-A showing internal dimensions thereof;
- Figure 4H is a schematic cross-sectional view of the cleaning head of Figure 4A along line B-B showing internal dimensions thereof;
- Figure 5 is diagrammatic perspective view of the cleaning head of Figure 4A showing flow trajectories of ambient air drawn into the vacuum port of the cleaning head and the pressure levels encountered.
- Figures 1 A and IB show inkjet printing apparatus 10 comprising an inkjet printhead assembly 20 movable across a print media on which ink for printing is to be applied.
- the inkjet printhead assembly 20 comprises a plurality of inkjet printing heads 30, each having a reservoir for ink fed from ink supply lines 40 and, as described hereinbelow, a printing surface comprising a nozzle plate 50 having an exposed exterior nozzle orifice surface 52 defining an array of orifices through which ink is ejected under microprocessor control.
- the printhead assembly 20 is also movable from its printing position ( Figure 1 A) to a maintenance position ( Figure IB) where purging and cleaning processes are performed.
- the maintenance position is defined by a purge tray 60 within which there is provided a contactless cleaning station 70 over which the inkjet printhead assembly 20 is moved reciprocally.
- the cleaning station 70 comprises an array of cleaning heads 80 mounted on an array block 90, the array of cleaning heads 80 being positioned to receive in close proximity respective printing heads 30 of the inkjet printhead assembly 20 during a cleaning cycle.
- Each cleaning head 80 includes a quick-connect coupling 82 provided for connecting a respective vacuum source to the cleaning head 80.
- Figure 2B shows a cleaning head 80 in juxtaposition to a nozzle plate 50 of an inkjet printing head 30.
- the inkjet printing head 30 includes a peripheral nozzle plate guard 32 configured to protect the nozzle plate 50 to be cleaned as the inkjet printing head 30 is moved progressively over the cleaning station 70.
- the exposed exterior nozzle orifice surface 52 corresponds to the visible part of the nozzle plate 50.
- vacuum source connecting pipes 72 (which pass through a side wall of the purge tray 60) connect to respective ones of the cleaning heads 80 via quick- connect couplings 82.
- Each of the cleaning heads 80 of the cleaning array is connected via its vacuum source connecting pipe 72 through a fluid trap 74 (via an air filter 73) to a respective vacuum source 75 of the cleaning station 70 (for simplicity only a single vacuum source and its associated parts are shown).
- Each fluid trap 74 is, in turn, connected to a common waste collection tank 77 via an ink separator drain pump 79.
- the waste outlet pipe 62 from the purge tank 60 also feeds to the common waste collection tank 77.
- each vacuum source 75 is a non-pulsatile, constant- velocity vacuum pump with sufficient rotor inertia to deal with vacuum pressure increases for short periods of time without dropping flowrate.
- each vacuum source 75 may be a rotary vane vacuum pump.
- the vacuum source 75 is set provide a vacuum source inlet (Fi) flowrate of substantially 36 litres/min in order to generate a flow rate at the inlet slot (Fs) of 26 litres/min at its respective cleaning head 80.
- Figures 3 and 4A-H show the array of cleaning heads 80 of the cleaning station 70 in more detail.
- each cleaning head 80 comprises a body 110 (formed as a single component, e.g. by 3D printing) having a longitudinal axis “A”.
- Body 110 defines a nozzle portion 120 featuring a vacuum port 130 configured to be coupled to vacuum source 75 via quick-connect couplings 82, and a base portion 140 supporting the nozzle portion 120.
- Nozzle portion 120 comprises: a tapered nozzle body 150 defining an external airflow guide surface 150A; and a tapered nozzle tip 160 surrounding a horizontal inlet slot 132 of the vacuum port 130 that extends laterally between opposed first and second laterally spaced side walls 122A, 122B of the nozzle portion 120.
- Tapered nozzle body 150 comprises inclined first and second opposed nozzle body side walls 152A, 152B having a first concave curved surface profile and inclined first and second opposed nozzle body end walls 154A, 154B (e.g. leading and trailing inclined nozzle body end walls relative to a forward direction) having a second concave curved surface profile.
- Tapered nozzle tip 160 comprises inclined first and second opposed substantially triangular nozzle tip side walls 162A, 162B and inclined first and second opposed substantially trapezoidal nozzle tip end walls 164A, 164B (e.g. leading and trailing inclined nozzle tip end walls relative to a forward direction).
- the first and second opposed nozzle tip end walls 164A, 164B are inclined by a first taper angle Bi and the first and second opposed nozzle tip side walls 162A, 162B are inclined by a second taper angle B2, wherein Bi > B2.
- the tapered nozzle body 150 has an uppermost tapered section 150’ inclined to vertical at a steeper taper angle than a corresponding taper angle of the corresponding adjacent section of the tapered nozzle tip 160.
- first and second opposed nozzle body end walls 154A, 154B have an uppermost tapered section 155A, 155B contiguous with tapered nozzle tip end walls 164A, 164B, the uppermost tapered sections 155A, 155B being inclined by a first taper angle Ai.
- the first and second opposed nozzle body side walls 152A, 152B have an uppermost tapered section 153 A, 153B contiguous with tapered nozzle tip side walls 162A, 162B, the upper most tapered sections 153 A, 153B being inclined by a second taper angle A2, wherein Ai > A2.
- taper angle Ai 31°
- taper angle A2 21°
- taper angle Bi 49°
- taper angle B2 34°.
- the inlet slot has a slot length SL (e.g. extending in the lateral direction) and a slot width Sw (e.g. extending in the longitudinal direction).
- the external dimensions of cleaning head 80 may be determined with reference to the slot inlet length “a” as illustrated.
- the value “a” is dependent upon the lateral width of the exposed exterior nozzle orifice surface 32 and is generally at least equal to this lateral width.
- nozzle portion 120 defines a passageway 134 defining a tapered internal chamber section 134A and an elongate entrance section 134B connecting the inlet slot 132 to the tapered internal chamber section 134A.
- Base portion 140 defines a vacuum source connection chamber 142 and the tapered internal chamber section 134A connects the elongate entrance section 134B to the vacuum source connection chamber 142.
- tapered internal chamber section 134A is profiled to act as an internal airflow guide surface to smoothly transition airflow passing from the elongate entrance section to the vacuum source connection chamber and comprises first and second opposed internal side walls 136A, 136B with a first convex curved surface profile and first and second opposed internal end walls 138A, 138B with a second convex curved surface profile.
- the internal flow path of chamber section 134A is sculpted by 3D printing to reduce turbulence at the inlet slot 132 and to ensure more constant air velocity at the inlet slot 132.
- the cross-sectional area SA of inlet slot 132 is extremely small compared to the internal cross-sectional area of its respective vacuum source connecting pipe 72 (approximately 3% of the internal area of the pipe 72) resulting in high air velocity at the inlet. This helps to create a large shear force at the printhead nozzle plate 50 to “scrape” the ink from the nozzle plate 50. The ink is pulled into the cleaning nozzle completely. It effectively works like an air knife, but in reverse (using negative vacuum pressure rather than positive pressure).
- the gap between the uppermost surface of the cleaning head 80 and the exposed exterior nozzle orifice surface of the nozzle plate 50 is maintained at all times at this constant distance (as set by a gauge block 100), ideally in the region of 0.145mm - 0.435mm and most preferably maintained at substantially 0.225mm. Within this range ensures that the negative pressure normal to the print head nozzle plate 50 is below the value that would pull ink out of the print head, whilst close enough to make the airflow into the inlet slot 132 shear the nozzle plate of the print head with a very high shear force.
- This distance is set using a high tolerance machined gauge block 100 (with a +/- 0.025mm height tolerance), which sets the nozzle height off the print head. Gauge block 100 is removed once the height is set, resulting in a completely contact-free assembly.
- the tapered nozzle body 150 is designed such that no ink is allowed to escape the cleaning nozzle inlet slot. If ink were to run down the outer face of the nozzle body 150 then it would cure on them and the print head cleaning would degrade over time due to the surface roughness of the cleaning nozzle changing, effecting ink wettability and airflow, possibly even blocking up the cleaning nozzle orifice eventually. A run of over 4000 cycles (5 year accelerated test) was conducted in testing and the cleaning nozzles remained clean throughout. This is in stark contrast to known cleaning systems which require manually nozzle cleaning at regular intervals.
- the inkjet printhead assembly 20 is moved from the printing position to the maintenance position passing over the cleaning station 70 to initiate a purge cycle above the purge tray 60.
- the vacuum source 75 is engaged to each cleaning head 80 of the cleaning station 70 and the inkjet printhead assembly 30 stops over the purge tray 60 to commence the purge cycle.
- Ink is initially flushed from within each printing head 30 out through the nozzle orifices of the exposed exterior nozzle orifice surface 52 into the purge tray. Ink that falls into the purge tray 60 is fed under gravity to a waste outlet pipe 62. When flushing is complete, a period is allowed to facilitate withdrawal of the ink meniscus back into the nozzle orifices 52 so that siphoning is prevented during the cleaning phase.
- the printhead assembly 20 is then traversed rearwardly (in the direction of the printing position) to the location where the cleaning heads 80 are mounted such that the exposed exterior nozzle orifice surfaces 52 of the respective printing heads 50 are brought into close proximity with the upper surface of the cleaning heads 80.
- Each printing head 30 is progressively moved passed its respective cleaning head 80 so that each nozzle orifice of the nozzle plate 50 is exposed to the high shear forces generated at the inlet slot 132 which act to scrape ink from the nozzle plate without the cleaning head 80 physically contacting the printing head 30.
- the removed ink and debris is drawn under vacuum through the vacuum port 130 and into respective fluid traps 74 where, once the level of accumulated ink has reached a sufficient volume, is pumped to the waste collection tank 77.
- the flushing step is recommenced once the printing head has moved over the purge tray.
- the number of repeats is predetermined according to the characteristic of the inks in use.
- Figure 6 is a diagrammatic illustration of fluid flow trajectories of ambient air under influence of the vacuum, generated via the vacuum port 130, around the cleaning head 80.
- First and second nozzle body end walls 154A, 154B are designed to deflect the air flow trajectory generated by vacuum port 130 upwardly against the nozzle plate 50 to generate sufficient shear forces to remove ink droplets and debris accumulated thereon.
- the curved profile of nozzle body end walls 154A, 154B are configured to smoothly guide airflow to an optimum angle for this purpose.
- the first and second opposed nozzle body side walls 152A, 152B act to supplement the airflow generated by end walls 154A, 154B.
- First and second nozzle tip end walls 164A, 164B and first and second nozzle tip side walls 162 A, 162B are designed to provide an inclined support surface for supporting ink droplets as they are drawn into inlet slot 132 of the vacuum port 130.
- the first and second nozzle tip end walls 164 A, 164B and first and second nozzle tip side walls 162 A, 162B are configured to discourage droplets from falling down the sides of the tapered nozzle body 150 whilst at the same time providing minimal disruption to the upward flow generated by nozzle body end walls 154A, 154B and nozzle body side walls 152A, 152B.
Landscapes
- Ink Jet (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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GB2316326.4A GB2620344A (en) | 2021-04-27 | 2022-04-20 | Cleaning head for inkjet printing apparatus |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB2106001.7A GB202106001D0 (en) | 2021-04-27 | 2021-04-27 | Cleaning head for inkjet printing apparatus |
GB2106001.7 | 2021-04-27 |
Publications (1)
Publication Number | Publication Date |
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WO2022229602A1 true WO2022229602A1 (en) | 2022-11-03 |
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Application Number | Title | Priority Date | Filing Date |
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PCT/GB2022/050992 WO2022229602A1 (en) | 2021-04-27 | 2022-04-20 | Cleaning head for inkjet printing apparatus |
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GB (2) | GB202106001D0 (en) |
WO (1) | WO2022229602A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003039710A (en) * | 2001-08-03 | 2003-02-13 | Hitachi Koki Co Ltd | Nozzle cleaning mechanism of ink jet head |
JP2011201308A (en) * | 2011-05-24 | 2011-10-13 | Ishii Hyoki Corp | Inkjet head wiping apparatus |
US20150144709A1 (en) * | 2013-11-22 | 2015-05-28 | Canon Kabushiki Kaisha | Liquid discharge apparatus and method for controlling the same |
WO2020058879A1 (en) * | 2018-09-18 | 2020-03-26 | Industrial Injket Limited | Printing apparatus with multi-head cleaning of inkjet printface and method of cleaning thereof |
WO2021008955A1 (en) * | 2019-07-12 | 2021-01-21 | Weidmüller Interface GmbH & Co. KG | Printer for printing plate-like print media, cleaning device for the printer and method for maintaining the printer |
-
2021
- 2021-04-27 GB GBGB2106001.7A patent/GB202106001D0/en not_active Ceased
-
2022
- 2022-04-20 GB GB2316326.4A patent/GB2620344A/en active Pending
- 2022-04-20 WO PCT/GB2022/050992 patent/WO2022229602A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003039710A (en) * | 2001-08-03 | 2003-02-13 | Hitachi Koki Co Ltd | Nozzle cleaning mechanism of ink jet head |
JP2011201308A (en) * | 2011-05-24 | 2011-10-13 | Ishii Hyoki Corp | Inkjet head wiping apparatus |
US20150144709A1 (en) * | 2013-11-22 | 2015-05-28 | Canon Kabushiki Kaisha | Liquid discharge apparatus and method for controlling the same |
WO2020058879A1 (en) * | 2018-09-18 | 2020-03-26 | Industrial Injket Limited | Printing apparatus with multi-head cleaning of inkjet printface and method of cleaning thereof |
WO2021008955A1 (en) * | 2019-07-12 | 2021-01-21 | Weidmüller Interface GmbH & Co. KG | Printer for printing plate-like print media, cleaning device for the printer and method for maintaining the printer |
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