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Electrostatic chuck and heater for developing thermal paper substrate to detect missing ink jets

IP.com Disclosure Number: IPCOM000239677D
Publication Date: 2014-Nov-24
Document File: 4 page(s) / 155K

Publishing Venue

The IP.com Prior Art Database

Abstract

This idea proposes a way of combining an electrostatic hold-down system and heater on a single printed wiring board (PWB) for use in a missing jet detection system. The proposed system loads thermal paper onto a cart and holds it in place using patterned electrodes which create an electrostatic field. After the ink jet material is jetted onto the thermal paper, the cart is docked, the paper is heated using heaters on the cart and an imaging system is used to identify any missing jets. Two scenarios for the integrated hold-down and heating system are described. In the first scenario, the heaters and electrostatic traces are part of a multi-layer PWB. In the second scenario, the same traces are used for both resistive heating and electrostatic hold-down.

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Electrostatic chuck and heater for developing thermal paper substrate to detect missing ink jets

This idea proposes a way of combining an electrostatic hold-down system and heater on a single printed wiring board (PWB) for use in a missing jet detection system. The proposed system loads thermal paper onto a cart and holds it in place using patterned electrodes which create an electrostatic field. After the ink jet material is jetted onto the thermal paper, the cart is docked, the paper is heated using heaters on the cart and an imaging system is used to identify any missing jets. Two scenarios for the integrated hold-down and heating system are described. In the first scenario, the heaters and electrostatic traces are part of a multi-layer PWB.  In the second scenario, the same traces are used for both resistive heating and electrostatic hold-down.

This idea can be employed in a system for detecting missing jets in a 3D printer using, for example, clear ink jet material.  Detecting missing ink jets would be difficult due to the transparency of the clear material. If thermal paper was used in the detection process, it would be heated after depositing ink jet material to make missing ink jets visible.  This idea proposes a way to hold the thermal paper down and heat it which would result in a way to observe missing ink jets.

This idea describes how you would combine an electrostatic chuck and a heater on a single PWB to enable holding and developing thermal paper in a missing jet detector system.  In operation, the missing jet cart would be docked, loaded with thermal paper and a voltage applied between the electrodes to hold the paper flat and in place. A typical voltage differential between the holding “fingers” might be as high as 1000V. Since the cart has no electrical connections once un-docked, a capacitor on the cart could be used to maintain this DC voltage. Once the thermal paper is printed upon, the cart is again docked in the loading/imaging/unloading station and the heater energized to develop or darken the thermal paper. The developed image is then optically imaged by a camera or scanned with an optical sensor to generate an image file. The image file is then processed to detect missing jets.

Electrostatic chucks have been around since the early 1970’s.  They work by applying a voltage between inter-digitated electrodes buried under a dielectric layer to attract and hold any object with a dielectric constant greater than 1. 

Here is a link to how they work.  http://electrogrip.com/Egrip2013Support/Principles7faq2.pdf

Resistive heating of circuit boards (PWB’s or PCB’s) is also well known in the electronics industry.

This idea describes how you would combine an electrostatic chuck and a heater on a single PWB to enable holding and developing thermal paper in missing jet detector system.

In operation, the missing jet cart would be docked, loaded with thermal paper and a voltage applied between the electrodes to hold...