Abstract: A sensor is paired with an emitter, such as in a postage metering machine, and the sensor is calibrated for ambient light conditions. Ambient light is measured with a sensor while the emitter is unpowered. If the measured ambient light is less than a current trip level (voltage level at the sensor), then a current level of light is measured with the sensor while the emitter is powered. If the measured current level of light exceeds the current trip level, then the signal output from the sensor indicates that an object such as an envelope awaiting postage to be printed thereon is present at the sensor. The current trip level may be determined by measuring light at the sensor when the emitter is on and adding some voltage margin to it, but if the sensor is blocked during this calibration a default threshold is used as the current trip level.

Abstract: A sensor is paired with an emitter, such as in a postage metering machine, and the sensor is calibrated for ambient light conditions. Ambient light is measured with a sensor while the emitter is unpowered. If the measured ambient light is less than a current trip level (voltage level at the sensor), then a current level of light is measured with the sensor while the emitter is powered. If the measured current level of light exceeds the current trip level, then the signal output from the sensor indicates that an object such as an envelope awaiting postage to be printed thereon is present at the sensor. The current trip level may be determined by measuring light at the sensor when the emitter is on and adding some voltage margin to it, but if the sensor is blocked during this calibration a default threshold is used as the current trip level.

Abstract: Apparatus and method for monitoring print quality produced by a digital printing mechanism in real-time. Print quality is measured by: generating a background reflectance signal representative of the reflectance of a substrate; scanning the image to generate a post-print reflectance signal; comparing the reflectance signal with the post-print reflectance signal; and, if the post-print reflectance signal is greater than a predetermined fraction of said reflectance signal, generating an output signal indicative of poor quality. In one embodiment of the invention, the output signal is also generated if the post-print reflectance signal is less than a predetermined minimum value.

Abstract: Apparatus and method for monitoring print quality produced by a digital printing mechanism in real-time. Print quality is measured by: generating a background reflectance signal representative of the reflectance of a substrate; scanning the image to generate a post-print reflectance signal; comparing the reflectance signal with the post-print reflectance signal; and, if the post-print reflectance signal is greater than a predetermined fraction of said reflectance signal, generating an output signal indicative of poor quality. In one embodiment of the invention, the output signal is also generated if the post-print reflectance signal is less than a predetermined minimum value.

Abstract: Predetermined print control signals are provided to a digital printing mechanism that responds to the print control signals to print an image on a substrate. A reference signal is derived from said print control signals. The image is scanned to generate a post-print signal. The reference signal is compared with said post-print signal. If the reference signal and the post-print signal do not compare within predetermined standards, an output signal indicative of poor print quality is generated. The print mechanism can be incorporated into a postage metering system and the image can be a postal indicia. The postage meter is responsive to a signal generated as a function of the output signal to inhibit further printing of postal indicia. Prior to printing the image, a substrate upon which the image is to be printed is scanned to generate a reflectance signal, the reflectance signal being used to correct the post-print signal.

Abstract: Apparatus and method for monitoring print quality produced by a digital printing mechanism in real-time. Print quality is measured by: generating a background reflectance signal representative of the reflectance of said substrate; scanning the image to generate a post-print reflectance signal; comparing said reflectance signal with said post-print reflectance signal; and, if said post-print reflectance signal is greater than a predetermined fraction of said reflectance signal, generating an output signal indicative of poor quality. In one embodiment of the invention, the output signal is also generated if the post-print reflectance signal is less than a predetermined minimum value. In another embodiment of the invention, the print mechanism is comprised in a postage metering system and the output signal inhibits further printing.