EP-4737876-A1 - METHOD FOR DETECTING A GAS EMISSION AND DETECTING DEVICE

EP4737876A1EP 4737876 A1EP4737876 A1EP 4737876A1EP-4737876-A1

Abstract

The present invention relates to a method for detecting a gas emission from a system, the method comprising the steps of providing a transparent or translucent carrier with a thermochromic layer on one side of the carrier and a heater on either side of the carrier, the thermochromic layer having an initial colour, placing the side of the carrier supporting the thermochromic layer facing the system, heating the thermochromic layer with the heater, the thermochromic layer colour changing to another colour due to an increase of temperature, operating the system, detecting a gas emission by determining a colour change of the thermochromic layer viewed through the transparent or translucent carrier due to the cooling of the thermochromic layer by the gas emission from the system. The invention also relates to a detecting device to detect gas emission.

Inventors

DEPAYE, Thibault
HEUSSCHEN, Kevin

Assignees

Schaeffler Technologies AG & Co. KG

Dates

Publication Date: 20260506
Application Date: 20241030

Claims (15)

A method for detecting a gas emission from a system (12), the method comprising the steps of - Providing a transparent or translucent carrier (14) with a thermochromic layer (16) on one side (141) of the carrier (14) and a heater (18) on either side (141, 142) of the carrier (14), the thermochromic layer (16) having an initial colour, - Placing the side (141) of the carrier (14) supporting the thermochromic layer (16) facing the system (12), - Heating the thermochromic layer (16) with the heater (18), the thermochromic layer (16) colour changing to another colour due to an increase of temperature, - Operating the system (12), - Detecting a gas emission (13) by determining a colour change of the thermochromic layer (16) viewed through the transparent or translucent carrier (14) due to the cooling of the thermochromic layer (16) by the gas emission from the system (12).
The method of the preceding claim, wherein the carrier (14) has an additional layer (34) of opaque colour paint, the thermochromic layer (16) being between the opaque colour paint layer (34) and the carrier (14).
The method of the preceding claims, wherein a power supply (20) is adjustable to change the sensitivity of detecting the gas emission.
The method of any one of the preceding claims, further comprising detecting and evaluating colour distribution of thermochromic layer (16), with an optical device (24) and/or with naked eye (26), through the carrier (14) and heater (18).
The method of any one of the preceding claims, wherein the color change due to the cooling of the thermochromic layer (16) is reversible.
The method of any one of the preceding claims, wherein the gas emission is a gas leakage or a gas ejection.
The method of the preceding claim, wherein the system (12) is a printhead with a matrix of ejection nozzles, the method detecting gas ejection and/or gas leakage through the printhead.
The method of the preceding claim, comprising an evaluation algorithm comprising: - After heating the thermochromic layer (16) and before operating the printhead, the method further comprising a step of taking an initial image (40) of the side (141) of the carrier (14) supporting the thermochromic layer (16), the initial image (40) being taken through the carrier (14), - Operating the printhead comprises setting all of the ejection nozzles of the matrix to the closed state and then enabling an ejection pressure, - Determining a colour change comprises taking a test image (42) of the thermochromic layer (16) through the carrier (14) after operating the printhead and identifying the areas with colour changes (43) between the test image (42) and the initial image (40).
The method according to the preceding claim, further comprising correlating the area(s) (431) with colour change(s) with the nearest nozzle(s) to tag the nozzle(s) as being not able to close.
The method according to the three preceding claims, further comprising determining area (432) of colour change that is not in an expected nozzle place and correlating said area with a leak in a sealing material of the print head.
The method of any one of the four preceding claims, comprising an evaluation algorithm comprising - After heating the thermochromic layer (16) and before operating the printhead, the method further comprising a step of taking an initial image of the side (141) of the carrier (14) supporting the thermochromic layer (16), the initial image (50) being taken through the carrier (14), - Operating the printhead comprises setting all of the ejection nozzles of the matrix to the eject state and then enabling an ejection pressure, - Determining a colour change comprises taking a test image (52) of the thermochromic layer (16) through the carrier (14) after operating the printhead and identifying the areas without colour changes (53) between the test image (52) and the initial image (50).
The method according to the preceding claim, further comprising correlating the area(s) (53) without colour change(s) with the nearest nozzle(s) to tag the nozzle(s) as being not able to eject.
A detecting device (10) to detect gas emission (13) from a system (12), the device comprising - a transparent or translucent carrier (14), - a transparent or translucent heater (18) on either side (141, 142) of the carrier (14), - a thermochromic layer (16) on one side (141) of the carrier (14), the thermochromic layer (16) having an initial colour, the thermochromic layer colour being configured ∘ to change to another colour due to an increase of temperature caused by the heater (18), and ∘ to change to the initial color due to the cooling of the thermochromic layer (16) by the gas emission from the system (12).
The device (10) of the preceding claim, wherein the carrier (14) is rigid or flexible and/or is held by a support structure (15) that is rigid or articulated.
The device (10) of the two preceding claims, wherein the heater (18) is a transparent conductive coating or a wired conductor.

Description

Technical field The invention relates to a method and a device for detecting a gas emission from a system. Prior art In the field of printheads, such systems are tested once manufactured. Currently, this test process is done with the same powders that are used for printing. The problem is that these powders are expensive and toxic. The debugging operator needs to wear proper personal protective equipment and clean the print head after debugging. This is annoying and time consuming. Moreover, problems in the ejection matrix of the printheads are only revealed at a late stage of the manufacture. Therefore, there is a need to develop a method to test the ejection matrix as soon as they are manufactured, before installing them in the print head. More generally, there is a need to develop a method to test a system at an early manufacturing stage. This test method also needs to be safe for the operator, so that there is no need to wear personal protective equipment. Disclosure of the invention A first object of the invention is to provide a method for detecting a gas emission from a system, the method comprising the steps of providing a transparent or translucent carrier with a thermochromic layer on one side of the carrier and a heater on either side of the carrier, the thermochromic layer having an initial colour; placing the side of the carrier supporting the thermochromic layer facing the system; heating the thermochromic layer with the heater, the thermochromic layer colour changing to another colour due to an increase of temperature; operating the system; detecting a gas emission by determining a colour change of the thermochromic layer viewed through the transparent or translucent carrier due to the cooling of the thermochromic layer by the gas emission from the system. According to an embodiment, the carrier has an additional layer of opaque colour paint, the thermochromic layer being between the opaque colour paint layer and the carrier. According to an embodiment, a power supply is adjustable to change the sensitivity of detecting the gas emission. According to an embodiment, the method further comprises detecting and evaluating colour distribution of thermochromic layer, with an optical device and/or with naked eye, through the carrier and heater. According to an embodiment, the color change due to the cooling of the thermochromic layer is reversible. According to an embodiment, the gas emission is a gas leakage or a gas ejection. According to an embodiment, the system is a printhead with a matrix of ejection nozzles, the method detecting gas ejection and/or gas leakage through the printhead. According to an embodiment, the method further comprises an evaluation algorithm comprising: After heating the thermochromic layer and before operating the printhead, the method further comprising a step of taking an initial image of the side of the carrier supporting the thermochromic layer, the initial image being taken through the carrier,Operating the printhead comprises setting all of the ejection nozzles of the matrix to the closed state and then enabling an ejection pressure,Determining a colour change comprises taking a test image of the thermochromic layer through the carrier after operating the printhead and identifying the areas with colour changes between the test image and the initial image. According to an embodiment, the method further comprises correlating the area(s) with colour change(s) with the nearest nozzle(s) to tag the nozzle(s) as being not able to close. According to an embodiment, the method further comprises determining area of colour change that is not in an expected nozzle place and correlating said area with a leak in a sealing material of the print head. According to an embodiment, the method further comprises an evaluation algorithm comprising After heating the thermochromic layer and before operating the printhead, the method further comprising a step of taking an initial image of the side of the carrier supporting the thermochromic layer, the initial image being taken through the carrier,Operating the printhead comprises setting all of the ejection nozzles of the matrix to the eject state and then enabling an ejection pressure,Determining a colour change comprises taking a test image of the thermochromic layer through the carrier after operating the printhead and identifying the areas without colour changes between the test image and the initial image. According to an embodiment, the method further comprises correlating the area(s) without colour change(s) with the nearest nozzle(s) to tag the nozzle(s) as being not able to eject. The invention also relates to a detecting device to detect gas emission from a system, the device comprising a transparent or translucent carrier, a transparent or translucent heater on either side of the carrier, a thermochromic layer on one side of the carrier, the thermochromic layer having an initial colour, the thermochromic layer colour being conf