CUTTING PAPER - COUNTING - Image Counting

Image Counting

An important source of data is "image counters" found on many devices. Many laserprinters print a sample output sheet either when turned on or requested from the control panel. Some of these sheets have the number of images the printer has made in one corner. By collecting several of these (from the same printer) some time apart, you can see how much printing is done on it. If the sample sheet comes out every time the printer is turned on, turn this "feature" off to avoid printing it when not needed.

Copiers usually have a counter inside that records the number of images made, and as with the printers, you can see how much it is used, by simply subtracting an early count from a later one. Copier counters used to be mostly mechanical counters similar to car odometers, and were found by opening the front door of the copier. In recent years, however, more of the counters are electronic and so are accessed from the control panel. See the Copier listings in the Actions area for information about specific counters.

Capacity Ratings for Copiers

Copiers are rarely used as much as manufacturers say they can be used. On average, people only make about 15% as many copies as the machines are supposed to be capable of. A common recommendation is to try to get copiers that are rated for twice the capacity that you expect to use. However, people generally want a faster copier than this would lead to, so most people buy more copying capability than they really need.

The following table shows the average capacity cited by manufacturers for several hundred copiers.

Average Copier "Capacity"

Speed (cpm)	Images per Month	Images per Year
<10	4,100	49,000
10-19	10,500	126,000
20-30	25,700	308,000
31-45	55,400	665,000
46-69	124,600	1,495,000
70-90	144,800	1,737,000
>91	430,000	5,160,000

You are most likely to have information about image counts, so to arrive at estimates of paper use, you need a duplexing rate for each machine. All imaging equipment is rated by the speed of operation (number of images made per minute). Estimates of national average duplexing rates are shown below. For laser printers, they essentially never can duplex for machines less than 10 pages per minute (ppm); rarely for 10 to 20 ppm; sometimes for 20-30; and usually for machines that operate faster than 30 ppm.

Estimates of typical duplexing rates found in offices are few and of uncertain quality. The only widely known estimate for U.S. copiers is based on figures produced in 1990 and is shown below.

Estimated U.S. Copier Duplexing Rates

Segment	Speed cpm	Duplexing Rate
PC	<10	0.0%
1	10-19	1.8%
2	20-30	4.6%
3	31-45	11.0%
4	46-69	18.0%
5	70-90	38.0%
6	>90	55.4%
Average		26%

Source: BIS, Inc., Boston, MA, 1991.

The speed is the rated copies per minute that the copier makes, and the duplexing rate is the fraction of images made on duplexed paper.

Printers

For printer duplexing, you are probably best off observing any duplexing printers you have and estimating from that. An HP savings calculator from 1994 provides estimate for duplexing rates from 15% to 75%. Most printers don’t have a duplexing unit.

Fax Machines

Faxes are an interesting case in that the person who sends the fax doesn't use extra paper (unless there is a confirmation sheet), but the sender incurs most of the cost in the form of the phone charge. Many fax machines take about 20 seconds to send each page, though you can easily time your machine on several faxes to confirm this. The send time depends on the speed of connection and the resolution used.

You may find, or be able to generate, periodic reports of fax activity; these can provide records of pages per week for both incoming and outgoing faxes, and an indication of the balance among local, long-distance, and international faxes (which indicates cost). Your phone bill for the fax line may indicate total transmission time, which, divided by the time per sheet, indicate pages sent. While the sheets of paper used is due to the incoming (not outgoing) faxes, you can observe the ratio between these from activity reports. Imaging costs for fax machines are similar to those for printers (although thermal fax machines differ sometimes)

Other Measures

Another aspect of imaging on paper is the toner (ink) and equipment maintenance. Copier toner and maintenance often costs 1 to 3 cents/image. Laser printer cartridges often cost 1 to 2 cents/image, with ink jet printer costs similar. You can use the amount of toner or ink bought as an indication of the number of copies made. However, you might use it considerably slower or faster than average, so use such estimates cautiously.

Imaging Equipment