Ink buildup sensor arrangement

Patent metadata

Field	Value
Publication number	US-10124584-B2
Application number	US-201715715693-A
Country	US
Kind code	B2
Filing date	Sep 26, 2017
Priority date	Jun 5, 2014
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A continuous ink jet print head (10), including: an ink droplet generator (116) configured to emit an ink droplet (158) along an undeflected droplet flight path (30); a charge electrode (118) configured to impart a charge to the ink droplet; deflector plates (120A, 120B) adjacent the undeflected droplet flight path, downstream from the charge electrode, and configured to deflect the ink droplet to a deflected droplet flight path that lies within a range of deflected flight paths bounded by at least deflected droplet flight path and a most deflected droplet flight path; a gutter (122) configured to receive an ink droplet traveling along the undeflected droplet flight path; and an ink buildup sensor (102) configured to detect an accumulation of ink (140) relative to a droplet flight path disposed within the range of deflected flight paths.

First claim

The invention claimed is:

1. A continuous ink jet print head, comprising:
an ink droplet generator configured to emit ink droplets along a droplet flight path;
a charge electrode configured to impart a charge to at least some of the ink droplets;
at least one deflector plate adjacent the droplet flight path, downstream from the charge electrode, and configured to deflect at least some of the ink droplets to a deflected droplet flight path;
a gutter configured to receive ink droplets not intended for printing; and
an ink buildup sensor configured to detect an accumulation of ink on a print head surface.

2. The continuous ink jet print head of claim 1 , wherein the ink buildup sensor comprises a light detector and a light emitter, wherein the light emitter and the light detector are configured such that the accumulation of ink reduces an amount of emitted light that is detected by the light detector.

3. The continuous ink jet print head of claim 2 , wherein the ink buildup sensor is configured to detect the accumulation of ink on an internal surface of the print head that is downstream of the deflector plates and external to an interior of the gutter.

4. The continuous ink jet print head of claim 3 , wherein the ink buildup sensor comprises a housing comprising a light emitting end and a light detecting end, wherein light emitted by the light emitter is emitted from the light emitting end in a direction generally transverse to the undeflected droplet flight path and is gathered by the light detecting end and delivered to the light detector.

5. The continuous ink jet print head of claim 4 , wherein the light emitter emits light into an emitter transparent cover disposed in the light emitting end, wherein the emitter transparent cover reflects the emitted light toward a sensor transparent cover disposed in the light detecting end, and wherein the sensor transparent cover reflects the light emitted from the emitter transparent cover and directs it toward the light detector.

6. The continuous ink jet print head of claim 2 , wherein the ink buildup sensor is configured to detect the accumulation of ink on an internal surface of the print head adjacent an inlet of the gutter.

7. The continuous ink jet print head of claim 2 , wherein the gutter is positioned between the light emitter and the light detector such that the accumulation of ink on an external surface of the gutter is effective to reduce the amount of emitted light that is detected by the light detector.

8. A continuous ink jet printing system, comprising the continuous ink jet print head of claim 2 and a controller in signal communication with the ink buildup sensor and configured to generate a signal indicative of the change in the amount of light sensed by the ink buildup sensor.

9. A continuous ink jet print head, comprising:
an ink droplet generator configured to emit an ink droplet along an undeflected droplet flight path;
a charge electrode configured to impart a charge to the ink droplet;
deflector plates adjacent the undeflected droplet flight path and configured to deflect the ink droplet to a deflected droplet flight path that lies within a range of deflected flight paths;
a gutter configured to receive an ink droplet traveling along the undeflected droplet flight path; and
an ink buildup sensor configured to infer an accumulation of ink that grows in a direction toward an ink droplet in flight on the deflected droplet flight path.

10. The continuous ink jet print head of claim 9 , wherein the ink buildup sensor comprises a light detector, and the ink buildup sensor is configured to generate a signal indicative of a reduction of light received by the light detector as a result of the accumulation of ink.

11. The continuous ink jet print head of claim 10 , wherein the ink buildup sensor is configured to generate an alarm signal when the signal indicative of the reduction of the light indicates a reduction in the light that exceeds a threshold value.

12. A continuous ink jet printing system, comprising the continuous ink jet print head of claim 10 and a controller in signal communication with the ink buildup sensor and configured to generate an alarm when the signal indicative of the reduction of the light indicates a reduction in the light that exceeds a threshold value.

13. The continuous ink jet print head of claim 9 , wherein the light detector comprises an image detector.

14. The continuous ink jet print head of claim 9 , wherein the ink buildup sensor comprises a light emitter disposed on an opposite side of the gutter than the light detector.

15. The continuous ink jet print head of claim 14 , wherein the ink buildup sensor comprises at least one reflecting surface configured to reflect light emitted from the light emitter.

16. A continuous ink jet print head, comprising:
an ink droplet generator configured to emit ink droplets along a droplet flight path;
a charge electrode configured to impart a charge to at least some of the ink droplets;
at least one deflector plate adjacent the droplet flight path, downstream from the charge electrode, and configured to deflect at least some of the ink droplets to a deflected droplet flight path;
a gutter configured to receive ink droplets not intended for printing;
an ink buildup sensor configured to detect an accumulation of ink on a print head surface; and,
wherein the ink buildup sensor is configured to detect the accumulation of ink on an internal surface of the print head that is downstream of the deflector plates and external to an interior of the gutter.

17. The continuous inkjet print head of claim 16 , where the ink buildup sensor configured to detect an accumulation of ink on a print head surface via a change in an amount of light sensed by the ink buildup sensor.

18. The continuous inkjet print head of claim 17 , wherein the ink buildup sensor comprises a light detector and a light emitter, wherein the light emitter and the light detector are configured such that the accumulation of ink reduces an amount of emitted light that is detected by the light detector.

19. The continuous ink jet print head of claim 16 , wherein the ink buildup sensor is configured to detect the accumulation of ink on an internal surface of the print head adjacent an inlet of the gutter.

20. The continuous inkjet print head of claim 19 , wherein the gutter is positioned between a light emitter and a light detector such that the accumulation of ink on an external surface of the gutter is effective to reduce the amount of emitted light that is detected by the light detector.

Assignees

• Videojet Technologies Inc

Inventors

• Smith Robert
• Omer Salhadin

Classifications

• B41J2/085

  Charge means, e.g. electrodes · CPC title

• B41J2/09

  Deflection means · CPC title

• B41J2/185

  Ink-collectors; Ink-catchers · CPC title

• B41J2/02

  generating a continuous ink jet · CPC title

• B41J2/04561

  detecting presence or properties of a drop in flight · CPC title