# US 11,999,172 B2 · Pre-treatments for ink-jet printing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,999,172 B2 - Document ID: US11999172B2 - Status: Granted - Kind: B2 - Application number: 17/641,777 - Filed: 2019-09-23 - Published: 2023-11-16 - Granted: 2024-06-04 - Earliest claimed: 2019-09-23 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Hewlett-Packard Development Company, L.P. - Inventors: Sara Benito Echevarria; Marta Blanch Pinol; Cristina Crespi Argemi - Web page: https://patentgrep.com/patent/US11999172B2 ## CPC - B41J 2/2103: {Features not dealing with the colouring process per se, e.g. construction of printers or heads, driving circuit adaptations} - B41J 2/2114: {Ejecting specialized liquids, e.g. transparent or processing liquids (B41J2/211 takes precedence)} - B41J 11/0015: {for treating before, during or after printing or for uniform coating or laminating the copy material before or after printing (selective coating B41J2/2114)} - B41J 11/009: {Detecting type of paper, e.g. by automatic reading of a code that is printed on a paper package or on a paper roll or by sensing the grade of translucency of the paper} - B41J 2203/011: Inspecting the shape or condition, e.g. wrinkled or warped, of a medium to be printed before printing on it - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract Disclosed herein is a print head arrangement, a printing device and a method of operating a printing device. The print head arrangement comprises a main print head having a plurality of printing nozzles for ejecting a printing fluid and an auxiliary print head having a plurality of pre-treatment nozzles for ejecting a pre-treatment fluid. The print head arrangement further comprises a controller that is to obtain a print medium parameter and to select a subset of the plurality of pre-treatment nozzles for application of the pre-treatment fluid based on the print medium parameter. The print medium parameter characterizes a thermal inertia of the print medium. ## Claims ### Claim 1 A print head arrangement comprising: a main print head having a plurality of printing nozzles for ejecting a printing fluid; an auxiliary print head having a plurality of pre-treatment nozzles for ejecting a pre-treatment fluid; and a controller that is to obtain a print medium parameter and to select a subset of the plurality of pre-treatment nozzles for application of the pre-treatment fluid based on the print medium parameter, wherein the print medium parameter characterizes a thermal inertia of the print medium, wherein the thermal inertia is a measure of how fast a temperature of the print medium increases when heating the print medium based on a heat capacity and a thermal conductivity of the print medium. ### Claim 2 (depends on 1) The print head arrangement of claim 1, wherein the print medium parameter further characterizes a porosity of the print medium. ### Claim 3 A print head arrangement comprising: a main print head having a plurality of printing nozzles for ejecting a printing fluid; an auxiliary print head having a plurality of pre-treatment nozzles for ejecting a pre-treatment fluid; and a controller that is to obtain a print medium parameter and to select a subset of the plurality of pre-treatment nozzles for application of the pre-treatment fluid based on the print medium parameter, wherein the print medium parameter characterizes a thermal inertia of the print medium, wherein the print medium parameter further characterizes a porosity of the print medium, and wherein the printing nozzles are distributed over a first distance perpendicular to a scanning direction, the pre-treatment nozzles are distributed over a second distance perpendicular to the scanning direction, the second distance partially overlaps with first distance, and the subset of pre-treatment nozzles is distributed over a third distance that: partially overlaps with the first distance for a first type of print medium; completely overlaps with the first distance for a second type of print medium; and does not overlap with the first distance for a third type of print medium, the first, second and third types of print medium having different print medium parameters. ### Claim 4 (depends on 1) The print head arrangement of claim 1, wherein the controller is to determine a number of nozzles in the subset of pre-treatment nozzles based on the print medium parameter. ### Claim 5 (depends on 1) The print head arrangement of claim 1, wherein the controller is to determine an amount of pre-treatment fluid to be ejected from the subset of pre-treatment nozzles based on the print medium parameter. ### Claim 6 (depends on 1) The print head arrangement of claim 1, wherein the controller is to select a masking mode for the subset of pre-treatment nozzles based on the print medium parameter. ### Claim 7 A printing device comprising a print head carriage and a controller, wherein: the print head carriage is movable along a scanning direction; the print head carriage comprises a main slot that is to receive a main print head with a plurality of printing nozzles and an auxiliary slot that is to receive an auxiliary print head with a plurality of pre-treatment nozzles; and the controller is to determine a print medium parameter and to select a subset of the plurality of pre-treatment nozzles for application of the pre-treatment fluid based on the print medium parameter, wherein the print medium parameter depends on a thermal inertia of the print medium, wherein the thermal inertia is a measure of how fast a temperature of the print medium increases when heating the print medium based on a heat capacity and a thermal conductivity of the print medium. ### Claim 8 (depends on 7) The printing device of claim 7, wherein the auxiliary slot partially overlaps with the main slot in a direction perpendicular to the scanning direction. ### Claim 9 A printing device comprising a print head carriage and a controller, wherein: the print head carriage is movable along a scanning direction; the print head carriage comprises a main slot that is to receive a main print head with a plurality of printing nozzles and an auxiliary slot that is to receive an auxiliary print head with a plurality of pre-treatment nozzles; and the controller is to determine a print medium parameter and to select a subset of the plurality of pre-treatment nozzles for application of the pre-treatment fluid based on the print medium parameter, wherein the print medium parameter depends on a thermal conductivity of the print medium, wherein the subset of pre-treatment nozzles: partially overlaps with the printing nozzles along a media advance direction, perpendicular to the scanning direction, for a first type of print medium; completely overlaps with the printing nozzles along the media advance direction for a second type of print medium; and does not overlap with the printing nozzles along the media advance direction for a third type of print medium, the first, second and third types of print medium having different print medium parameters. ### Claim 10 (depends on 7) The printing device of claim 7, further comprising a media type detector that is to detect the type of print medium. ### Claim 11 (depends on 7) The printing device of claim 7, wherein the controller is to determine a number of passes of the print head carriage for applying the pre-treatment fluid based on the type of print medium. ### Claim 12 A method of operating a printing device, wherein the printing device comprises a set of print heads with a plurality of printing nozzles for ejecting a printing fluid and a plurality of pre-treatment nozzles for ejecting a pre-treatment fluid, the method comprising: determining a category that a print medium to be used with the printing device is associated with; selecting a pre-treatment scheme depending on the category of the print medium, wherein print media are grouped into the categories based on a thermal inertia of the print media, wherein the thermal inertia is a measure of how fast a temperature of the print medium increases when heating the print medium based on a heat capacity and a thermal conductivity of the print medium. ### Claim 13 (depends on 12) The method of claim 12, further comprising: repeatedly passing the set of print heads across the print medium in a scanning direction; and applying the pre-treatment fluid and the printing fluid onto the print medium according to the pre-treatment scheme, wherein, for a first category of print media, the pre-treatment scheme comprises: ejecting pre-treatment fluid from a first pre-treatment nozzle during a first pass of the set of print heads without ejecting printing fluid from printing nozzles aligned with the first pre-treatment nozzle along the scanning direction during the first pass; and ejecting pre-treatment fluid from a second pre-treatment nozzle during a second pass of the set of print heads and ejecting printing fluid from a printing nozzle aligned with the second pre-treatment nozzle along the scanning direction during the second pass. ### Claim 14 A method of operating a printing device, wherein the printing device comprises a set of print heads with a plurality of printing nozzles for ejecting a printing fluid and a plurality of pre-treatment nozzles for ejecting a pre-treatment fluid, the method comprising: determining a category that a print medium to be used with the printing device is associated with; selecting a pre-treatment scheme depending on the category of the print medium, wherein print media are grouped into the categories based on a heat capacity of the print media, the method further comprising: repeatedly passing the set of print heads across the print medium in a scanning direction; and applying the pre-treatment fluid and the printing fluid onto the print medium according to the pre-treatment scheme, wherein, for a first category of print media, the pre-treatment scheme comprises: ejecting pre-treatment fluid from a first pre-treatment nozzle during a first pass of the set of print heads without ejecting printing fluid from printing nozzles aligned with the first pre-treatment nozzle along the scanning direction during the first pass; and ejecting pre-treatment fluid from a second pre-treatment nozzle during a second pass of the set of print heads and ejecting printing fluid from a printing nozzle aligned with the second pre-treatment nozzle along the scanning direction during the second pass, wherein the pre-treatment scheme further comprises: for a second category of print media, for each pre-treatment nozzle from which pretreatment fluid is ejected during a pass of the set of print heads, ejecting printing fluid from a printing nozzle aligned with the respective pre-treatment nozzle along the scanning direction; and for a third category of print media, ejecting pre-treatment fluid from a set of pre-treatment nozzles during a pass of the set of print heads without ejecting printing fluid from any printing nozzle aligned with a nozzle of the set of pre-treatment nozzles along the scanning direction. ### Claim 15 (depends on 12) The method of claim 12, further comprising obtaining a fine-tuning parameter, wherein the fine-tuning parameter characterizes at least one of a thermal inertia and a porosity of the print medium and wherein the pre-treatment scheme is selected depending on the category of the print medium and the fine-tuning parameter.