Patent Description:
<CIT> discloses a method of transferring and mixing ink for printing comprising transferring ink from a supply container into a mixing area of a tank and transferring mixed ink from the mixing area to the printing device.

One of the challenges of inkjet printing is that pigment-based inkjet inks are prone to pigment settling. Inconsistent pigment loading in inkjet printing ink results in image quality anomalies. One approach is to mitigate pigment settling in inkjet inks prior to printing, e.g., to mix the ink in the supply container prior to evacuating the ink. For large commercial graphics printing devices, however, mixing the ink in the container prior to removing the ink from the container is often not practical. Supply containers for commercial graphic inkjet printers are commonly <NUM> to <NUM> liters in volume, and are not conducive to the shake mixing that might be effective for a smaller printer ink supply (e.g., an inkjet cartridge for a desktop printer). And while having a supply and return connection at the supply container to enable recirculation mixing within the ink supply is feasible for some commercial graphics printing applications, other applications utilize ink supply containers with a single connection to the printing system that does not facilitate recirculation mixing. For example, cost effective "bag in box" supply containers (in which a bag holding ink collapses as the ink is evacuated) typically have a single needle/septum connection with the printing system and thus are not conducive to ink recirculation.

To address these issues, various examples described in more detail below provide a system and a method for ink transfer and mixing when utilizing large ink supply containers common to commercial graphics printing. The disclosed solution addresses pigment settling/mixing for bag in box supplies by transferring a supply volume of new ink, at one time, into an intermediate tank with the shape of a funnel or an inverted cone. In examples, the ink flow enters the tank through an inlet tube that is elevated and angled away from the outlet port so that ink circulates up and radially around the intermediate tank to mix the new ink with resident ink from the printing device that is also being introduced into the tank. The transfer and mixing are done at a flow rate that allows the new ink and the resident ink to be well mixed prior to reaching an outlet port on the bottom of the intermediate tank and being pumped to printheads at the printing device.

In certain examples, the transferring of the new ink from the supply container to the mixing area includes transferring a total volume of new ink in the supply container without interruption. In certain examples, a sensor is utilized to determine ink level in the intermediate tank. Upon determination that mixed ink in the intermediate tank has dropped below a refill threshold level, the system initiates an additional transfer of ink to the mixing area from a new supply container. In yet another example, upon determination that mixed ink in the intermediate tank has dropped below an empty/stop operations threshold level, the system causes printing operations to stop so as to not damage the printing device.

In this manner, the disclosed method, ink mixing apparatus, and printing device provide for effective and efficient mixing in an intermediate tank of new ink from a supply container and resident ink already in the printing device. The disclosed method promotes consistent pigment uniformity for printing, and improved print quality. Users and providers of inkjet printer systems will appreciate these improvements in print quality, and will further appreciate the reductions in damage to printing system components and reductions in downtime afforded by the disclosed examples. Users and providers of inkjet printer systems will further appreciate that a series of ink supply containers can be staged and sequentially connected to the intermediate tank ready for access when the ink level in the intermediate tank reaches a threshold level. This allows for adding new ink to the printing system without interrupting printing operations. Installations and utilization of inkjet printers that include the disclosed method, ink mixing apparatus, and printing device should thereby be enhanced.

According to the invention, a method of transferring and mixing ink for printing is disclosed in independent claim <NUM>. A corresponding ink transfer and mixing apparatus is disclosed in independent claim <NUM>.

<FIG> is a block diagram depicting an example of an apparatus <NUM> for transferring and mixing inks for printing utilizing an intermediate tank. In this example, apparatus <NUM> includes an intermediate tank <NUM> for mixing new ink from a connected supply container and resident ink from a connected printing device. As used herein, "tank" refers generally to any receptacle or storage chamber capable of holding liquid ink. In examples, intermediate tank <NUM> may be a tank made of plastic or any other polymer composition. In other examples, intermediate tank <NUM> could be made of other materials such as a metal (e.g., aluminum or steel), ceramic, or glass.

As used herein, a "printing device" is synonymous with a "printer", and refers generally to any electronic device or group of electronic devices that consume a marking agent to produce a printed print job or printed content. In examples, a printer may be, but is not limited to, a liquid inkjet printer, a liquid toner-based printer, or a multifunctional device that performs a function such as scanning and/or copying in addition to printing. As used herein, a "print job" refers generally to content, e.g., an image, and/or instructions as to formatting and presentation of the content sent to a computer system for printing. In examples, a print job may be stored in a programming language and/or a numerical form so that the job can be stored and used in computing devices, servers, printers and other machines capable of performing calculations and manipulating data. As used herein, an "image" refers generally to a rendering of an object, scene, person, or abstraction such text or a geometric shape. In certain examples, a "printing device" may be a 3D printer. In certain examples, the printed print job or printed content may be a 3D rendering created by a 3D printer printing upon a bed of marking agent or other build material.

Intermediate tank <NUM> has a mixing area <NUM> that is formed by a funnel shaped, or inverted conical shaped, portion of intermediate tank <NUM>. In certain examples the mixing area <NUM> of intermediate tank <NUM> is made of the same material as the non-mixing areas (e.g., the portion above the mixing area) of the tank. In other examples, mixing area <NUM> may be made of different material than the non-mixing area. In certain examples, the mixing area portion <NUM> and non-mixing areas of intermediate tank <NUM> may be made from a same material, yet have different wall thicknesses.

Continuing at <FIG>, apparatus <NUM> includes a new ink supply inlet tube <NUM> for depositing into intermediate tank <NUM> the new ink from a connected ink supply container. In examples, new ink supply inlet tube <NUM> may be connected via tubing, e.g. new ink connective tubing (<NUM> FIG. 2A), to a "bag in box" supply container (a box container holding a collapsible bag, with the bag holding the new ink). The bag is to collapse as the ink is evacuated. In examples, new ink supply inlet tube <NUM> may be connected direct or indirectly, e.g., via removable new ink connective tubing (<NUM> FIG. 2A), to an ink supply container that has a single needle/septum connection with the tubing.

Apparatus <NUM> includes a resident ink supply inlet tube <NUM> for depositing into intermediate tank <NUM> ink, via resident ink connective tubing (<NUM> FIG. 2A), from a connected printing device (referred to herein as "resident ink"). In examples, the resident ink may be ink that originated from (e.g., was transferred to the printing device from) an ink supply container, but has circulated through the printing device as a result of a printing operation, a pre-printing operation (e.g., a print device warm-up routine), or a servicing operation (e.g., an ink spitting routine to clear a clogged printhead). In examples, resident ink supply inlet tube <NUM> may be connected directly or indirectly, to the printing device via connective tubing.

In examples, new ink supply inlet tube <NUM> and resident ink supply inlet tube <NUM> may be made of a metal, a plastic or other polymer, or any other material capable of transferring liquid ink into mixing area <NUM>. In certain examples, each of the new ink supply inlet tube <NUM> and the resident ink supply inlet tube <NUM> has a first length that extends upward from the tank bottom, and a second length that is angled outward towards a wall of the intermediate tank. In a particular example, the second length of one or both of new ink supply inlet tube <NUM> and resident ink supply inlet tube <NUM> are angled between <NUM> degrees and <NUM> degrees from vertical. This arrangement is to allow, with the assistance of a transfer pump to provide pressure, the new ink and the resident ink to be sprayed upon the interior walls of mixing area <NUM>. The new ink and the resident ink are to be sprayed upon the interior walls of funnel shaped, or inverted conical shaped, mixing area <NUM> with force sufficient to cause the new ink and the resident ink to circulate and mix in mixing area <NUM>.

Continuing at <FIG>, apparatus <NUM> includes an outlet port <NUM> that is situated at the bottom of intermediate tank <NUM>. Outlet port <NUM> is for sending the mixed ink to the printing device that was the source of the resident ink. The mixed ink is a mixture of new ink from the ink supply container and resident ink from the printing device, where the mixing occurs in funnel-shaped or inverted conical-shaped mixing area <NUM>.

<FIG> is a schematic diagram showing a cross-section view of an example of an apparatus <NUM> for transferring and mixing inks for printing. In this example, apparatus <NUM> includes an intermediate tank <NUM> that has a mixing area <NUM> formed by a funnel or inverted conical portion of the tank. Mixing area <NUM> is for mixing new ink and resident ink. In the example of <FIG>, the top or upper boundary <NUM> of the mixing area <NUM> is indicated by a horizontal broken line that extends across the diameter of intermediate tank <NUM>.

Apparatus <NUM> includes a new ink supply inlet tube <NUM> for depositing into intermediate tank <NUM> the new ink from a connected ink supply container (not shown in <FIG>), and a resident ink supply inlet tube <NUM> for depositing into intermediate tank <NUM> the resident ink from a connected printing device (not shown in <FIG>). In examples, the deposits of the new ink and the resident ink into mixing area <NUM> are contemporaneous to cause mixing of the new ink and the resident ink Apparatus <NUM> includes an outlet port <NUM> situated at the bottom <NUM> of intermediate tank <NUM>. Outlet port <NUM> is for sending the mixed ink to the connected printing device via a mixed ink outlet tubing <NUM>.

<FIG> is a schematic diagram showing a cross-section view of another example of an apparatus <NUM> for transferring and mixing inks for printing. In this example, apparatus <NUM> includes an intermediate tank <NUM> that has a mixing area <NUM> formed by a funnel or inverted conical portion of the tank. Mixing area <NUM> is for mixing new ink and resident ink. Apparatus <NUM> includes a new ink supply inlet tube <NUM> for depositing into intermediate tank <NUM> the new ink from a connected ink supply container (not shown in <FIG>), and a resident ink supply inlet tube <NUM> for depositing into intermediate tank <NUM> the resident ink from a connected printing device (not shown in <FIG>). Apparatus <NUM> includes an outlet port <NUM> situated at the bottom of intermediate tank <NUM>. Outlet port <NUM> is for sending the mixed ink to the connected printing device via a mixed ink outlet tube <NUM>.

<FIG> is a perspective view of an example an integrated component <NUM> that can be seated at the bottom of an intermediate tank <NUM> (<FIG>). In this example, integrated component <NUM> includes all or a portion of new ink supply inlet tube <NUM>, resident ink supply inlet tube <NUM>, and outlet port <NUM>. In an example, the integrated component may include a plastic or other polymer composition, metal, rubber (e.g., for a gasket or for a seating member), and/or other materials. In this example, each of new ink supply inlet tube <NUM> and resident ink supply inlet tube <NUM> has a first length <NUM> that is to extend upward from the tank bottom (<NUM> <FIG>), and a second length <NUM> that is to be angled outward towards a wall of intermediate tank <NUM> in the mixing area <NUM> (<FIG>). The angled structure allows, with the assistance of a transfer pump to provide sufficient pressure, the new ink and the resident ink to be sprayed upon the interior walls of intermediate tank <NUM> in mixing area <NUM>.

Returning to <FIG>, in examples new ink supply inlet tube <NUM> and resident ink supply inlet tube <NUM> each extend vertically though the bottom of the shaped intermediate tank, with each having a height <NUM> that is sufficient to extend into mixing area <NUM> well above the outlet port <NUM>. The heights of new ink supply inlet tube <NUM> and resident ink supply inlet tube <NUM> are to be tall enough to ensure the new ink and the resident ink will be deposited by new ink supply inlet tube <NUM> and resident ink supply inlet tube <NUM> onto the funnel or inverted conical shaped walls of intermediate tank <NUM> in the mixing area <NUM>. The new ink and the resident ink are to be deposited with sufficient force to cause the inks to circulate around, e.g., radially, the interior walls of the funnel or inverted conical shaped mixing area before exiting via outlet port <NUM>. In particular examples the heights of one or both of new ink supply inlet tube <NUM> and resident ink supply inlet tube <NUM> are between <NUM>% and <NUM>% of the height <NUM> of the mixing area <NUM>. In the example of <FIG>, the height <NUM> of the mixing area <NUM> is indicated by a broken line which extends vertically from bottom of intermediate tank <NUM> to the top upper boundary <NUM> of the funnel shaped or inverted conical shaped mixing area <NUM>. In the example of <FIG>, the top or upper boundary <NUM> of mixing area <NUM> is indicated by a horizontal broken line that extends across the diameter of intermediate tank <NUM>.

<FIG> is a schematic diagram showing a cross-section view of an example of an apparatus <NUM> for transferring and mixing inks for printing wherein the intermediate tank <NUM> is full after a transfer of all ink from an ink supply container. In this example "full" means that the ink has reached or exceeded a threshold of liquid volume that has been predetermined to be a maximum desired capacity for intermediate tank <NUM> (a "full threshold <NUM>). In this example the ink in intermediate tank <NUM> includes a first volume of ink <NUM> in the mixing area <NUM> denoted with horizontally hashed lines, and second volume of ink <NUM> in an area of intermediate tank <NUM> above mixing area <NUM>, the second volume of ink indicated by diagonal hashed lines.

In the example of <FIG>, "full" is actually a threshold volume point that is less than having intermediate tank <NUM> be filled to a point that is the maximum physically possible <NUM>. Overfilling intermediate tank <NUM> to the point of ink spillage or creating abnormal pressures in intermediate tank <NUM> would be a highly detrimental event in terms of damage to equipment, lost time, and ruined print jobs. Having the system recognize a "full" threshold be a detected volume that is less than actual physical capacity of intermediate tank <NUM>, then, affords margin for error such that a sensor error is less likely to result in damaged equipment.

<FIG> is a schematic diagram showing a cross-section view of another example of apparatus <NUM> for transferring and mixing inks for printing. In this example, apparatus <NUM>, upon a determination (e.g., receiving data originating from a sensor) that the mixed ink <NUM> in intermediate tank <NUM> is at or beneath the ink low threshold level <NUM>, initiates an additional transfer of ink into mixing area <NUM> from a new or fresh ink supply container. In this example the ink low threshold level <NUM> is a fluid level that is between a tank "full" level (<NUM> <FIG>) and a tank empty/stop operations level (<NUM> <FIG>), and has been predetermined to be an ideal level for initiating a resupply of intermediate tank <NUM>. Connecting a new or fresh ink supply container, directly or indirectly, to new ink supply inlet tube <NUM> (e.g. by connecting to new ink connective tube <NUM> that connects to new ink supply inlet tube <NUM>) at the time that "low" level <NUM> is indicated is to allow enough time for the refilling of mixing area <NUM> without having to stop printing operations. In other words, printing operations do not need to be suspended because at the "low" level <NUM> there is enough mixed ink in mixing area <NUM> to sustain printing operations through the refill process assuming the refill operation proceeds at an expected rate. Suspending print operations to enable refilling can be highly detrimental to commercial printing schedules. Causing refilling at a time that is far enough in advance of the ink level reaching an empty/stop operations level will result in significant savings in terms of time and increased productivity. In an example, "initiating" transfer may include sending a user message or instruction that a new or fresh ink supply container needs to be moved into proximity of intermediate tank <NUM>, and connected to new ink supply inlet tube <NUM>, e.g., via new ink connective tubing <NUM>. In another example, "initiating" transfer may include automatically moving a new or fresh ink supply container into proximity of intermediate tank <NUM>, and connecting the new ink supply container to new ink supply inlet tube <NUM> via new ink connective tubing <NUM>. It should be noted that while in the example of <FIG> the low threshold level is a level that is the top of funnel or inverted conical-shaped mixing zone <NUM>, in other examples the low threshold level could be a predetermined threshold level this higher than, or lower than, threshold level <NUM> depicted in <FIG>.

<FIG> is a is a schematic diagram showing a cross-section view of an example of an apparatus for transferring and mixing inks for printing, wherein the ink level in the intermediate tank has fallen below the low threshold level (<NUM> <FIG>) to an empty/stop operations level <NUM>, and printing operations are to be shut down. The change in ink levels may be due to the printing device having utilized the mixed ink that had resided in mixing areas <NUM> more before the ink level could be replenished by adding ink from a new ink supply container. In this example, upon determining the mixed ink <NUM> level in intermediate tank <NUM> is at or beneath the empty/stop operations level <NUM>, apparatus <NUM> causes an immediate cessation of printing operations. In one example, printing operations may only resume after there has been a transfer of additional ink from an ink supply container into intermediate tank <NUM>. Should the mixed ink <NUM> level drop below the output port <NUM>, output port <NUM> would draw air into the mixed ink output tubing <NUM> that leads to the printheads of the printing device and serious damage to the printing device, a ruined print job, and delays for repair may result. While in the example of <FIG> the empty/stop operations threshold level is a level that is roughly even with the height <NUM> of new ink supply inlet tube <NUM> and resident ink supply tube <NUM>, in other examples the stop operations threshold level could be a predetermined threshold level this higher than, or lower than, empty/stop operations threshold level <NUM> depicted in <FIG>.

In an example depicted in <FIG> ink transfer and mixing apparatus <NUM> may include a sensor <NUM> for determining ink levels in the intermediate tank <NUM>. In examples sensor <NUM> may be any sensor type that directs a sense beam <NUM> towards mixing area <NUM> to detect the level or volume of ink <NUM> in the intermediate tank <NUM>. In examples, sensor <NUM> may be an ultrasonic level sensor, a radar level transmitter, a guided microwave level transmitter, or any type of level or volume sensor. Moving to <FIG> in view of <FIG>, <FIG>, sensor <NUM> may direct a sense beam <NUM> towards mixing area <NUM> to detect that ink in intermediate tank is at an ink full threshold <NUM>, an ink low threshold level <NUM>, and/or an empty/stop operations level <NUM>.

<FIG> is a simple schematic diagram that illustrates an example of a printing system <NUM> that includes an intermediate tank <NUM> with a funnel or inverted conical shape mixing area <NUM> for mixing new ink <NUM> from an ink supply container <NUM> and resident ink <NUM> from a printing device <NUM>. In this example, printing device <NUM> may be an inkjet web fed printing device that delivers ink to media utilizing a set of printbars, with each printbar including a set of printheads <NUM>. In other examples, printing device <NUM> may be any other type of printing device that consumes liquid ink.

Intermediate tank <NUM> is connected by tubing to printing device <NUM> and new ink supply container <NUM>. Intermediate tank <NUM> includes a mixing area <NUM> formed by an inverted conical shape or a funnel shape for mixing new ink <NUM> and resident ink <NUM>. Intermediate tank <NUM> includes an outlet port <NUM> situated at the bottom <NUM> of tank bottom <NUM>, the outlet port <NUM> for sending mixed ink <NUM> to the printheads <NUM>.

Continuing at <FIG>, Printing system <NUM> includes a new ink supply inlet tube <NUM> connected to intermediate tank <NUM>. New ink supply inlet tube <NUM> is for streaming into the tank the new ink <NUM> from the connected ink supply container <NUM>. Printing system <NUM> includes a resident ink supply inlet tube <NUM> connected to intermediate tank <NUM> and printing device <NUM>. Resident ink supply inlet tube <NUM> is for streaming into the tank resident ink <NUM> from printing device <NUM>. In the example of <FIG> both the new ink supply inlet tube <NUM> and resident ink inlet tube have a first length that extends vertically from bottom of the conically shaped tank, and a second length that is angled from vertical, to cause the spraying of new ink <NUM> and resident ink <NUM> onto the interior walls of mixing area <NUM> of tank <NUM>.

Printing system <NUM> includes a transfer pump <NUM> connected to new ink supply inlet tube <NUM> and situated in line between ink supply container <NUM> and intermediate tank <NUM>. Transfer pump <NUM> is to cause the transfer of new ink <NUM> from ink supply container <NUM> to intermediate tank <NUM>. Printing system <NUM> includes a pressure pump <NUM> connected to resident ink supply inlet tube <NUM> and situated in line between printing device <NUM> and intermediate tank <NUM>.

Pressure pump <NUM> is to cause the transfer of mixed ink <NUM> from intermediate tank <NUM> to printing device <NUM> in order that mixed ink <NUM> can be ejected by printheads <NUM>. In this example pressure sensor <NUM> is connected to the tubing for connecting outlet port <NUM>, printing device <NUM>, and resident ink supply inlet tube <NUM>. Pressure sensor <NUM> is to measure the pressure at which mixed ink <NUM> is being provided to the printing device and/or the pressure at which resident ink being sent to mixing area <NUM> via resident ink supply inlet tube <NUM>.

Continuing at <FIG>, printing system <NUM> includes a filter <NUM> and a degas unit <NUM> that are connected by tubing with outlet port <NUM> and are connected by tubing with printing device <NUM>. Filter <NUM> is for removing contaminants from mixed ink <NUM> prior to the mixed ink being utilized in a printing operation at printing device <NUM>. Degas unit <NUM> is for removing bubbles in mixed ink <NUM> prior to the printheads <NUM> at printing device <NUM> ejecting mixed ink <NUM> upon a media.

<FIG> is a flow diagram of implementation of a method for transferring and mixing ink. In an example, ink is transferred from a supply container into a mixing area of an intermediate tank through a new ink supply inlet tube. The mixing area has a funnel shape or an inverted conical shape (block <NUM>).

Resident ink is transferred from a printing device into the mixing area through a resident ink supply inlet tube. The transfers of the new ink and the resident ink into the mixing area are contemporaneous and cause mixing of the new ink and the resident ink (block <NUM>).

Mixed ink is transferred from the mixing area to the printing device through an outlet port situated at bottom of the intermediate tank (block <NUM>).

<FIG> aid in depicting the architecture, functionality, and operation of various examples. In particular, <FIG> depict various physical and logical components. Various components are defined at least in part as programs or programming. Each such component, portion thereof, or various combinations thereof may represent in whole or in part a module, segment, or portion of code that comprises executable instructions to implement any specified logical function(s). Each component or various combinations thereof may represent a circuit or a number of interconnected circuits to implement the specified logical function(s). Examples can be realized in a memory resource for use by or in connection with a processing resource. A "processing resource" is an instruction execution system such as a computer/processor based system or an ASIC (Application Specific Integrated Circuit) or other system that can fetch or obtain instructions and data from computer-readable media and execute the instructions contained therein. A "memory resource" is a non-transitory storage media that can contain, store, or maintain programs and data for use by or in connection with the instruction execution system. The term "non-transitory" is used only to clarify that the term media, as used herein, does not encompass a signal. Thus, the memory resource can comprise a physical media such as, for example, electronic, magnetic, optical, electromagnetic, or semiconductor media. More specific examples of suitable computer-readable media include, but are not limited to, hard drives, solid state drives, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash drives, and portable compact discs.

Although the flow diagram of <FIG> shows specific orders of execution, the order of execution may differ from that which is depicted. For example, the order of execution of two or more blocks or arrows may be scrambled relative to the order shown. Also, two or more blocks shown in succession may be executed concurrently or with partial concurrence. Such variations are within the scope of the present disclosure.

It is appreciated that the previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the present disclosure.

Claim 1:
A method of transferring and mixing ink for printing, comprising:
transferring ink from a supply container into a mixing area (<NUM>) of a tank (<NUM>) through a new ink supply inlet tube (<NUM>), wherein the mixing area (<NUM>) has an inverted conical shape;
transferring resident ink from a printing device (<NUM>) into the mixing area (<NUM>) through a resident ink supply inlet tube (<NUM>),
wherein the transfers of the new ink and the resident ink into the mixing area (<NUM>) are contemporaneous and cause mixing of the new ink and the resident ink; and
transferring mixed ink from the mixing area (<NUM>) to the printing device (<NUM>) through an outlet port (<NUM>) situated at bottom of the tank (<NUM>).