Glossmeter for providing a linear response corresponding to true gloss readings

• US 3,890,049 A
• Filed: 09/17/1973
• Issued: 06/17/1975
• Est. Priority Date: 09/17/1973
• Status: Expired due to Term

• Current Assignee: Donald S. Collins, Patrick J. Peoples
• Original Assignee: Donald S. Collins, Patrick J. Peoples
• Inventors: Collins, Donald S., Peoples, Patrick J.
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US05/397,993
• Time in Patent Office: 638 Days
• Field of Search: 356/199,200,209-212,207 350/63 250/227,559,561,571
• US Class Current: 356/429
• CPC Class Codes: G01N 21/57 Measuring gloss
• CPC Class Codes: G01N 33/346 Paper sheets

Abstract

A glossmeter which includes an optical head, designed to conform with TAPPI Standard 480, and an electrical console connected to the optical head by fiber optics. The optical head transmits signals corresponding to the gloss of a surface to the console. When the surface is that of a vibrating paper web, only those signals which correspond to the gloss of the surface in the measurement plane are selected by the electrical console for recording. A purge gas is introduced into the optical head to prevent the accumulation of particulate matter on the lens surface.

Claims

1. A glossmeter which comprises:

means to measure continuously the gloss of a surface of a web, and to provide a continuous electrical signal corresponding to the gloss of the measured surface;

means to define a measurement plane through which the web moves into and out of, the signals from the surface of the web corresponding to a true gloss reading when the web is in said measurement plane; and

means to select for recording only those signals of the continuously transmitted signals corresponding to the value of the gloss from the surface of the web passes through the measurement plane.

2. means to select for recording only those output signals corresponding to the value of the gloss on the surface of the web as it passes through the measurement plane.

3. The glossmeter of claim 2, wherein the means to pick and store includes a sample-and-hold circuit.

4. The glossmeter of claim 1, which includes means to provide a reference beam and a measuring beam, the measuring beam striking and emerging from the surface to be measured.

5. The glossmeter of claim 4, which includes means to attenuate the reference beam.

6. The glossmeter of claim 5, which includes means to attenuate optically the reference beam.

7. The glossmeter of claim 4, which includes means to receive the reference and measuring beams and to provide an output directly proportional to the difference between said beams.

8. The glossmeter of claim 7, wherein the means to receive the reference and measuring beams includes photocells in combination with a first differential amplifier.

9. The glossmeter of claim 8, which includes a sample-and-hold circuit which receives the output of the first differential amplifier.

10. The glossmeter of claim 9, which includes a second differential amplifier adapted to receive the output of the sample-and-hold circuit.

11. The glossmeter of claim 10, wherein the output of the second differential amplifier is a voltage.

12. The glossmeter of claim 1, which includes:

a source to provide a beam of energy;

means to split the beam of energy into a reference beam and a measuring beam;

first receiving means in optical alignment with the splitting means to receive the reference beam and direct the reference beam to a reference receptor;

second receiving means in optical alignment with the splitting means to receive the measuring beam and direct it to the surface of the moving web;

third receiving means to receive the measuring beam emerging from the surface of the moving web and to direct it to a measuring receptor; and

means to compare the signals received by the reference and measuring receptors.

13. The glossmeter of claim 12, wherein the reference and measuring receptors are photocells.

14. The glossmeter of claim 12, wherein the second and tHird receiving means define the measurement plane.

15. The glossmeter of claim 1, which includes means to purge the optical components of the glossmeter.

16. The glossmeter of claim 15, wherein the glossmeter includes baffles disposed therein to define a conduit through which the purge gas flows.

17. A glossmeter which comprises:

A. means to provide a reference beam and a measuring beam, the measuring beam striking and emerging from the surface of a web to be measured;

B. means to define a measurement plane through which the web moves into and out of, the signals from the surface of the web corresponding to a true gloss reading when the surface of the web is in said measurement plane; and

C. means to measure continuously the gloss of the surface of the web which includes;

18. The glossmeter of claim 17, wherein the means to measure includes:

photocells adapted to receive the reference and measuring beams and to provide an output directly proportional to the difference between said beams;

a first differential amplifier adapted to receive said output; and

a sample-and-hold circuit adapted to receive the output of the first differential amplifier and to output to a second differential amplifier only those signals corresponding to the gloss of the surface of the web as it passes through the measurement plane.

19. The glossmeter of claim 17, which includes means to purge the optical components of the glossmeter.

20. The glossmeter of claim 17, wherein the means to provide the reference and measuring beams and the means to define the measurement plane includes:

means to split a beam of energy into a reference and a measuring beam;

first receiving means in optical alignment with the splitting means to receive the reference beam and direct the reference beam to a reference receptor;

second receiving means in optical alignment with the splitting means to receive the measuring beam and direct it to the surface of the web;

third receiving means to receive the measuring beam emerging from the surface of the moving web and direct it to a measuring receptor; and

means to compare the signals received by the reference and measuring receptors.

21. A method of measuring the gloss of a moving surface which includes:

measuring continuously the gloss of a surface;

providing a continuous signal corresponding to the gloss of a measured surface; and

selecting for recording only those signals of the continuously transmitted signals corresponding to the value of the gloss as the web passes through the measurement plane.

22. The method of claim 21 which includes holding for a predetermined period of time those signals selected corresponding to the maximum gloss reading.

23. The method of claim 21, which includes:

providing a reference beam;

providing a measuring beam;

comparing the measuring and reference beams;

producing an output proportional to the difference between the measuring and reference beams; and

selecting for recording only those output signals of the continuously transmitted signals corresponding to the value of the gloss as the web passes through a measurement plane.

24. The method of claim 23, which includes optically attenuating the reference beam prior to the producing the output proportional to the difference between the reference and measuring beams.

25. The method of claim 21, which includes purging the optical surfaces of the glossmeter.