Browse Prior Art Database

Improved Copier Background Measurement Technique

IP.com Disclosure Number: IPCOM000048734D
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 3 page(s) / 27K

Publishing Venue

IBM

Related People

Bankert, NR: AUTHOR [+2]

Abstract

The improved technique described involves substantially simultaneous reflectance measurements of original paper and the same paper after passing through a copier. This is accomplished by cutting the copy paper and passing a part through the copier.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 54% of the total text.

Page 1 of 3

Improved Copier Background Measurement Technique

The improved technique described involves substantially simultaneous reflectance measurements of original paper and the same paper after passing through a copier. This is accomplished by cutting the copy paper and passing a part through the copier.

The present procedure for measuring the amount of background produced on a copy sheet by a plain paper copier comprises the following steps:
(1) Measure paper reflectance at specified areas on a paper;
(2) Use the pre-measured paper in a copier to copy an "all-white"

master;
(3) Measure paper reflectance at the same specified areas on the

resulting copy; and
(4) Subtract the second reflectance value from the first to

obtain the background measurement.

The above procedure has several disadvantages. The measuring technician sometimes fails to insert the all-white master when copying on the pre-measured sheet. When first testing new machines requiring adjustments, feed errors frequently invalidate pre-measurements. Each of these cases requires an entirely new set of pre-measurements.

The delay between pre-measurement and post-measurement introduces errors of variation. For example, colorimeter drift over a 24-hour period can change the reflectance standard deviation by 0.05. Repeatability errors of measurement in calibrating the colorimeter and placement of the paper to be measured can affect the standard deviation by 0.03.

Reproducibility errors of measurement, caused by the calibration of the colorimeter by others between pre-and-post measurements, can affect the standard deviation by as much as 0.10.

The measurements per se cause a change in the humidity and paper fiber color. This affects the standard deviation by 0.02.

The aging of the paper between measurements can cause a significant change in the humidity of the paper.

The amount of time delay between pre-and post-measurements varies from a few minutes to several days, e.g., over a weekend. Recalibrating the colorimeter for post-measurements may require a significant period of time.

The new procedure comprises the following steps (see the figure):
(1) Number the top and bottom corners of e...