Ricoh AP 3800C [12/77] About calibration

Printing Guideline for Ricoh Color Products 2.01

4 About Calibration

To get expected and consistent colors together with ICC proÞ les it is necessary to

perform a calibration.

Note: Choose the same paper type for calibration as you want to use for your

prints.

4.1 Understanding Calibration

Calibration is the process of adjusting your output device (color copier or color laser

printer) to compensate for factors that affect the quality of a color print, e.g.

changes in environmental conditions etc. In addition, calibration is a process for

adjusting your output device to a certain color status. This status is deÞ ned by

gamma curves for the four colors yellow, magenta, cyan and black, the colors of

the toner. These gamma curves describe the color space or gamut of the output

device or, in other words, deÞ ne the range of colors that can be printed on it.

There are different methods of calibration for the different Ricoh products.

4.2 Calibration Methods

Auto Calibration Color Laser Printers usually calibrate themselves

during warm-up or after a certain amount of prints or changes of environmental

conditions. This process often is diplayed on the operation panel as ‚calibrating...‘.

The frequency of this auto-calibration can be set by the service technician.

AutoColorCalibration (ACC) Color Copiers usually have a calibration feature for

copy and print process, which can be performed by the user. It is a menu-driven

process run from the operation panel, which involves printing a calibration sheet,

placing it on the copier‘s platen glass and scanning it. By reading (scanning) it‘s

actual status from the calibration sheet and comparing it to the target the program

can then calculate and apply the necessary adjustments. Service technicians can set

parameters deÞ ning the calibration target.

Controller Calibration Depending on the type of controller connected to a

copier or printer, there are several types of more advanced, controller-panel-driven

or application-driven calibration methods. They always involve printing and reading a

calibration sheet and calculating the necessary adjustments by comparing the actual

to the target status. The calibration sheet is either read by the copier‘s platen glass

or a external densitometer. Application-based calibration give the user control over

measurement and target data.

Note: If more than one calibration method is executed, the order should be

from printing engine (Þ rmware based) to client PC (software based). E.g. if a copier/

controller offers both ACC and controller calibration, then start with the copier-panel-

driven (Þ rmware based) ACC calibration, and perform the (software based) controller

calibration afterwards.