Patent Description:
Ink jet printer systems typically use a columnar array of print elements or nozzles to be swept horizontally across a printed medium while the nozzles selectively print points that represent printed pixels. To achieve optimal quality and speed, some printer systems includes multiple ink reservoirs to allow switching between color modes to achieve different printing speeds. However, switching between different ink reservoirs can introduce air into the ink lines and reservoirs, thereby impacting printing quality. There exists a need to reduce the impact of air to printer systems while achieving a balance between printing speed and quality. A printing system which is capable of printing high quality images using several colored inks and printing images at high speeds with fewer colored inks is shown in <CIT>.

This document discloses embodiments related to methods, devices, and systems that use multiple selector valves to ensure that inks of different colors are returned to the proper reservoirs during recirculation. The disclosed techniques can ensure that primary ink reservoirs are not contaminated during print mode switches. Furthermore, the disclosed techniques allow fresh, degassed ink to be provided to the print heads after recirculation.

One aspect of the disclosed embodiments relates to a printer system that includes, for each of one or more ink color groups, a first primary ink tank holding a dark-colored ink, a second primary ink tank holding a light-colored ink, a first selector valve configured to change a state according to a print mode of the system, a first secondary ink tank connected to the first primary ink tank via the first selector valve, a second secondary ink tank connected to the first and second primary ink tanks via the first selector valve, a second selector valve connected to the first primary ink tank configured to return the dark-colored ink from the first or the second set of print heads to the first primary ink tank, and a third selector valve connected to the second selector valve and the second primary ink tank configured to either return the light-colored ink from the second set of print heads to the second primary ink tank or to direct the dark-colored ink to the second selector valve. The first secondary ink tank is configured to store the dark-colored ink and to provide the dark-colored ink to a first set of print heads. The second secondary ink tank is configured to store either the dark-colored ink or the light-colored ink and to provide the dark-colored ink or the light-colored ink to a second set of print heads according to the state of the first selector valve.

Another aspect of the disclosed embodiments relates to a method for switching a printing color of a printer system. The printer system comprises a first primary ink tank holding a dark-colored ink, a second primary ink tank holding a light-colored ink, a secondary ink tank, and a selector valve. The method includes drawing an existing ink from the secondary ink tank to either the first primary ink tank or the secondary primary ink tank based on a color of the existing ink, purging the existing ink from the secondary ink tank, operating the selector valve to fill the secondary ink tank with a different ink, flushing the secondary ink tank and corresponding ink lines using the different ink, and circulating the secondary ink tank and the corresponding ink lines to remove remaining air. The different ink is drawn from either the second primary ink tank or the first primary ink tank according to the color of the existing ink.

The details of one or more implementations are set forth in the accompanying attachments, the drawings, and the description below.

Ink jet printer systems are adapted for printing images using a carriage that holds a set of print heads across a printed medium while the print heads deposit ink as the medium moves. Such printer systems typically use different colored inks to achieve the desired images. In general, a greater number of colored inks leads to a higher-quality final image than those generated with fewer colored inks. In many applications, printer systems that support multiple modes, for example, one mode using a higher number of colored inks and one mode using a lower number of colored inks, can be used to adaptively achieve quality and speed according to the image.

In general, the printer system <NUM> prints images using various color groups, including black, yellow, cyan, magenta, and white. Dark-colored inks thus include at least black (BLK), yellow (Y), cyan (C), and magenta (M). To achieve a better printing quality, the printer system <NUM> also uses corresponding light-colored inks for each group, such as light black (LBLK), light yellow (LY), light cyan (LC), and light magenta (LM). In some implementations, the printer system <NUM> also uses the same color for the white color group. That is, there is no different between the dark-colored white and the light-colored white.

<FIG> illustrates an example schematic diagram of a printer system <NUM> that supports multiple printing modes to achieve an optimal combination of quality and speed. In <FIG>, there are two example primary ink reservoirs, also referred to as ink tanks, of the printer system <NUM>: the dark primary tank <NUM> and the light primary tank <NUM>. A set of secondary tanks are provided by the printer system <NUM>. A dark secondary tank <NUM> is connected to the dark primary tank <NUM>. A light/dark secondary tank <NUM> is connected to either the dark primary tank <NUM> or the light primary tank <NUM> via a selector valve <NUM>. The printer system <NUM> also includes a first set of print heads <NUM> and a second set of print heads <NUM>. The first set of print heads <NUM> takes ink from the dark secondary tank <NUM> and thus deposits dark colors (e.g., BLK, Y, C, or M) onto the printed medium. The second set of print heads <NUM> takes ink from the light/dark secondary tank <NUM> and thus is capable of depositing either light colors or dark colors onto the printed medium.

The selector valve <NUM> allows the printer system <NUM> to operate in at least two modes. For example, in the quality mode, the first set of print heads <NUM> receives dark-colored inks from the dark secondary tank <NUM> and the second set of print heads <NUM> receives light-colored inks from the light/dark secondary tank <NUM>, thereby printing images using eight colors. To switch to the fast mode, the selector valve <NUM> allows the light/dark secondary tank <NUM> to draw ink from the dark primary tank <NUM>. Both the first and second set of print heads <NUM>, <NUM> can receive dark-colored inks, thereby printing images using four colors only.

However, switching between the dark and light primary tanks can introduce additional air into the print heads, the ink lines, and the secondary tanks, which impacts the printing quality of the printer systems. To improve printing quality, reliability, and performance, printers are increasingly being designed to recirculate ink between the main ink supply and the inkjet print heads. The recirculation printer systems circulate ink through the print heads and return it to the ink tanks to carry away and filter out any particles or air introduced by the print nozzles. The recirculation can also keep ink temperature and viscosity uniform. Recirculation designs must ensure that inks are returned to the proper primary tanks without possibly contaminating the entire tank. When switching between the light and dark inks, however, the secondary tanks and corresponding ink lines may potentially contain a mixture of light and dark colors, posing a challenge for recirculation designs in multi-color printer systems. Disclosed herein are techniques that can be implemented in various embodiments to ensure that recirculation can be properly provided for printer systems that support multiple color modes for faster printing.

<FIG> illustrates an example schematic diagram of a recirculation printer system <NUM> that supports multiple printing modes in accordance with the present technology. The printer system <NUM> uses at least one dark primary tank <NUM> and one light primary tank <NUM>. A dark secondary tank <NUM> is connected to the dark primary tank <NUM>. A light/dark secondary tank <NUM> is connected to either the dark primary tank <NUM> or the light primary tank <NUM> via a selector valve <NUM>. The printer system <NUM> also includes a first set of print heads <NUM> and a second set of print heads <NUM>. The first set of print heads <NUM> takes ink from the dark secondary tank <NUM> and thus deposits dark colors (e.g., BLK, Y, C, or M) onto the printed medium. The second set of print heads <NUM> takes ink from the light/dark secondary tank <NUM> and thus deposits either light colors or dark colors onto the printed medium. The printer system <NUM> optionally includes a first tertiary tank <NUM> and a second tertiary tank <NUM> to draw fluids from a plurality of print heads at the same time.

To enable recirculation of the inks, the printer system <NUM> includes multiple selector valves <NUM>, <NUM> and ink lines to allow the ink from the secondary or tertiary tanks to return to the primary tanks. In some embodiments, the selector valve is a three-way solenoid valve to manage the selection of correct primary tanks to return the ink to. For example, as shown in <FIG>, the selector valve <NUM> is a three-way solenoid valve to select either the first tertiary tank <NUM> or the second tertiary tank <NUM> (via the selector valve <NUM>) so that dark ink can be returned to the dark primary tank <NUM>. The selector valve <NUM> is also a three-way solenoid valve to either return the light ink from the second tertiary tank <NUM> to the light primary tank <NUM>, or to direct the dark ink from the second tertiary tank <NUM> to the other selector valve <NUM>.

In some embodiments, a light secondary tank and a dark secondary tank can be organized in a pair so that a selector valve can control both for properly switching the colors. <FIG> illustrates a schematic diagram of a pair of secondary tanks and corresponding selector valves in accordance with the technology. In <FIG>, a dark secondary tank 307a is connected to a first valve <NUM> via ink line <NUM>. In a normal open (NO) state of the first valve <NUM>, the dark ink is fed back to the corresponding primary tank via ink line <NUM>. When the first valve <NUM> is energized, the first valve <NUM> turns into a normal closed (NC) state such that the first valve <NUM> is connected to a second valve <NUM>. The second valve <NUM> is also connected to a light secondary tank 307b that forms a pair with the dark secondary tank 307a. Thus, the second valve <NUM> controls a pair of light/dark secondary tanks 307a, 307b and can switch between them to draw ink to the correct primary tank to enable faster printing when necessary.

In some embodiments, the printer system determines when to perform color switch based on how much ink is left in the secondary tanks. For example, the secondary tanks can include a flow indicator that indicates the position of the ink, such as "Low" or "Full. " When the flow indicator indicates that the ink is low, the valve that controls the secondary tank can be operated to fill the secondary tank. At the same time, the valve draws ink from the other secondary tank in the pair as a part of the recirculation process.

In some embodiments, a primary tank may contain a large amount of ink, for example, <NUM> liters of ink. Contaminating the primary tanks causes a significant waste of the inks. Thus, the recirculation state must be set correctly so that inks from the secondary tanks are not sent to the wrong primary tank. In some embodiments, the printer system includes a computer system or a control device to ensure that there is no contamination when switching colors. <FIG> is a block diagram illustrating an example of the architecture for a computer system or a control device <NUM> of the printer system that can be utilized to implement various portions (e.g., controlling the array of nozzles) of the presently disclosed technology. In <FIG>, the control device <NUM> includes one or more processors <NUM> and memory <NUM> connected via an interconnect <NUM>. The interconnect <NUM> may represent any one or more separate physical buses, point to point connections, or both, connected by appropriate bridges, adapters, or controllers. The interconnect <NUM>, therefore, may include, for example, a system bus, a Peripheral Component Interconnect (PCI) bus, a HyperTransport or industry standard architecture (ISA) bus, a small computer system interface (SCSI) bus, a universal serial bus (USB), IIC (I2C) bus, or an Institute of Electrical and Electronics Engineers (IEEE) standard <NUM> bus, sometimes referred to as "Firewire. " The processor(s) <NUM> may include central processing units (CPUs), graphics processing units (GPUs), or other types of processing units (such as tensor processing units) to control the overall operation of, for example, the host computer. In certain embodiments, the processor(s) <NUM> accomplish this by executing software or firmware stored in memory <NUM>. The processor(s) <NUM> may be, or may include, one or more programmable general-purpose or special-purpose microprocessors, digital signal processors (DSPs), programmable controllers, application specific integrated circuits (ASICs), programmable logic devices (PLDs), or the like, or a combination of such devices. The memory <NUM> can be or include the main memory of the computer system. The memory <NUM> represents any suitable form of random access memory (RAM), read-only memory (ROM), flash memory, or the like, or a combination of such devices. In use, the memory <NUM> may contain, among other things, a set of machine instructions which, when executed by processor <NUM>, causes the processor <NUM> to perform operations to implement embodiments of the presently disclosed technology. Also connected to the processor(s) <NUM> through the interconnect <NUM> is a (optional) network adapter <NUM>. The network adapter <NUM> provides the computer system <NUM> with the ability to communicate with remote devices, such as the storage clients, and/or other storage servers, and may be, for example, an Ethernet adapter or Fiber Channel adapter.

<FIG> is a flowchart representation of a changeover process <NUM> that can be performed by a control device to switch from a light color to a dark color in accordance with the present technology.

Operation <NUM>: The printer system disables refilling of the light secondary ink tank.

Operation <NUM>: The printer system draws light ink from the secondary ink tank back to the primary ink tank until the flow indicator indicates that the tank is empty. The secondary ink tank is then purged to make sure the ink lines are empty as well. The purge operation is to ensure that there is no contamination in the ink lines after the recirculation. In some implementations, the purge operation can last around <NUM> to <NUM> seconds. If the printer system includes one or more tertiary tanks, the tertiary tanks are also purged. After the purge, ink bubbles may only present on the face of each print head in the color channel.

Operation <NUM>: The printer system is placed in a rest mode to allow ink to settle to low points of the secondary ink tank assembly. In some implementations, the printer system can rest between <NUM> to <NUM> minutes to allow the ink to settle. The assembly, including the ink lines and the tanks, can also be purged again after resting.

Operation <NUM>: After the purge operation is completed, the printer system energizes the selector valves to fill the emptied secondary ink tank with dark ink until ink level indicates "Full" position. The system then flushes the ink lines to make sure that any remaining light ink is pushed out.

Operation <NUM>: The printer system runs recirculation for a period of time (e.g., <NUM>-<NUM> minutes) to remove any remaining light ink or air, and to push the dark ink to the print heads. The system can also perform additional purge operations, if necessary.

<FIG> is a flowchart representation of a changeover process <NUM> that can be performed by the control device to switch from a dark color to a light color in accordance with the present technology.

Operation <NUM>: The printer system draws the dark ink from the secondary ink tank back to the primary ink tank until the flow indicator indicates that the tank is empty. In some embodiments, the secondary ink tank is then purged to make sure the ink lines are empty as well. Because there is a higher risk of contamination when switching from a dark color to a light color, additional purge time can be added to make sure that the ink assembly is clear. For example, the purge operation here can last about <NUM> seconds. If the printer system includes one or more tertiary tanks, the tertiary tanks are also purged. After the purge, ink bubbles may only present on the face of each print head in the color channel.

Operation <NUM>: The printer system is placed in a rest mode to allow ink to settle to low points of the secondary ink tank assembly. In some implementations, the printer system can rest for <NUM> minutes to allow the ink to settle. The assembly, including the ink lines and the tanks, can then be purged again.

Operation <NUM>: After the purge operation is completed, the printer system de-energizes the selector valves to fill the emptied secondary ink tank with light ink until ink level indicates "Full" position. The system then flushes the ink lines to make sure that any remaining dark ink is pushed out.

Operation <NUM>: Because there is a higher risk of contamination when switching from a dark color to a light color, the filling and flushing in Operation <NUM> are repeated again.

Operation <NUM>: The printer system runs recirculation for a period of time (e.g., <NUM> minutes) to remove any remaining light ink or air, and to push the light ink to the print heads. The system can also perform additional purge operations, if necessary.

The changeover processes depicted in <FIG> and <FIG> can be performed according to the desired printing quality and speed for the image.

<FIG> is an example schematic diagram of a recirculation configuration in accordance with the present technology. As shown in <FIG>, a degasser <NUM> is placed on an ink line between the primary ink tank <NUM> and a corresponding secondary tank (not shown). The placement of the degasser allows the recirculation process to provide freshly degassed paint to secondary tanks, thereby further enhancing the printing quality of the printer system.

<FIG> is a flowchart representation of a method <NUM> for switching a printing color of a printer system. The printer system comprises a first primary ink tank holding a dark-colored ink, a second primary ink tank holding a light-colored ink, a secondary ink tank, and a selector valve. The method <NUM> includes, at operation <NUM>, drawing an existing ink from the secondary ink tank to either the first primary ink tank or the secondary primary ink tank based on a color of the existing ink. The method <NUM> includes, at operation <NUM>, purging the existing ink from the secondary ink tank. The method <NUM> includes, at operation <NUM>, operating the selector valve to fill the secondary ink tank with a different ink. The different ink is drawn from either the second primary ink tank or the first primary ink tank according to the color of the existing ink. The method <NUM> includes, at operation <NUM>, flushing the secondary ink tank and corresponding ink lines using the different ink. The method <NUM> includes, at operation <NUM>, circulating the secondary ink tank and the corresponding ink lines to remove remaining air.

In some embodiments, the method includes disabling refilling of the secondary ink tank prior to drawing the existing ink. In some embodiments, drawing the existing ink includes determining an ink level of the secondary ink tank based on an indicator, and drawing the existing ink in case the ink level indicates that the secondary ink tank is empty. In some embodiments, the existing ink is a light-colored ink, and purging the existing ink can last between <NUM> to <NUM> seconds.

In some embodiments, the printer system further comprises a tertiary tank for drawing ink from a set of print heads, and the method further comprises purging the existing ink from the tertiary ink tank. In some embodiments, the method includes placing the printer system in a rest mode to allow the existing ink to settle to a low point of the secondary ink tank. In some embodiments, the printer system is placed in the rest mode for <NUM> to <NUM> minutes.

In some embodiments, the existing ink is a dark-colored ink and the different ink is a light-colored ink, and the method further comprises operating the selector valve to fill the secondary ink tank again; and flushing the secondary ink tank and corresponding ink lines using the light-colored ink again. In some embodiments, the secondary ink tank and the corresponding ink lines are circulated for <NUM> to <NUM> minutes.

From the foregoing, it will be appreciated that specific embodiments of the presently disclosed technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the appended claims.

The disclosed and other embodiments, modules, and the functional operations described in this document, for example, the control device, can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this document and their structural equivalents, or in combinations of one or more of them. The disclosed technology and other embodiments can be implemented as one or more computer program products, for example, one or more modules of computer program instructions encoded on a computer readable medium for execution by, or to control the operation of, a data processing apparatus. The apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, for example, a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.

The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, for example, an field programmable gate array (FPGA) or an application specific integrated circuit (ASIC).

Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, for example, magnetic, magneto optical disks, or optical disks. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including by way of example semiconductor memory devices, for example, EPROM, EEPROM, and flash memory devices; magnetic disks, for example, internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks.

Claim 1:
A printer system (<NUM>), comprising, for each of one or more ink color groups:
a first primary ink tank (<NUM>) holding a dark-colored ink;
a second primary ink tank (<NUM>) holding a light-colored ink;
a first selector valve (<NUM>) configured to change a state according to a print mode of the system (<NUM>);
a first secondary ink tank (<NUM>) connected to the first primary ink tank (<NUM>) via the first selector valve (<NUM>), the first secondary ink tank (<NUM>) configured to store the dark-colored ink and to provide the dark-colored ink to a first set of print heads (<NUM>);
a second secondary ink tank (<NUM>) connected to the first and second primary ink tanks (<NUM>, <NUM>) via the first selector valve (<NUM>), the second secondary ink tank (<NUM>) configured to store either the dark-colored ink or the light-colored ink and to provide the dark-colored ink or the light-colored ink to a second set of print heads (<NUM>) according to the state of the first selector valve (<NUM>);a second selector valve (<NUM>) connected to the first primary ink tank (<NUM>) configured to return the dark-colored ink from the first or the second set of print heads (<NUM>, <NUM>) to the first primary ink tank (<NUM>);
a third selector valve (<NUM>) connected to the second selector valve (<NUM>) and the second primary ink tank (<NUM>) configured to either return the light-colored ink from the second set of print heads (<NUM>) to the second primary ink tank (<NUM>) or to direct the dark-colored ink to the second selector valve (<NUM>); and
a control device configured to:
initiate, based on the print mode of the system (<NUM>), a changeover process for switching an ink stored in the second secondary ink tank (<NUM>); and
operate the third selector valve (<NUM>) to perform the changeover process, wherein the changeover process comprises:
drawing an existing ink from the second secondary ink tank (<NUM>) to a corresponding primary tank (<NUM>, <NUM>);
purging the existing ink from the second secondary ink tank (<NUM>);
filling the second secondary ink tank (<NUM>) with a different ink;
flushing the second secondary ink tank (<NUM>) and corresponding ink lines using the different ink; and
circulating the second secondary ink tank and the corresponding ink lines to remove remaining air.