US 6,642,492 B2 · Calibration apparatus for light emitting elements in an optical printer

Abstract

Calibration of the light emitting elements in an optical printer is carried out by mounting the optical printer on an external monitoring apparatus. The external monitoring apparatus comprises: a sensor mounting portion whereon a plurality of photosensors are mounted in a straight line; a signal processing circuit for processing the signals output from the photosensors; a reference voltage generating circuit; and a comparison and control circuit for comparing the output from the signal processing circuit with the reference voltage from the reference voltage generating circuit and outputting a signal based on the results of the comparison. The photosensors receive the light output from the light emitting elements, being subject to calibration, in the optical printer. The signal processing circuit comprises a plurality of integrating circuits which receive the signals output from the plurality of photosensors and integrate those signals over a prescribed period of time; and an arithmetic circuit for calculating the mean value of the output of the integrating circuits and outputting the calibration voltage.

Claims24

Dependent claims

An optical printer which forms images on a photosensitive body by the exposure of the photosensitive body, comprising:

an optical head for exposing the photosensitive body, the optical head including a light source, an optical shutter to control transmission and blockage of light from said light source, and a plurality of photosensors including a first photosensor to detect light, which was irradiated from the light source but has not yet passed through said optical shutter, and output a corresponding signal;
a reference value storing circuit for storing a value of a voltage;
and
a first comparison and control circuit for comparing the voltage of the signal outputted from said first photosensor with the value stored in said reference value storing circuit to control a quantity of light from said light source;
wherein said photosensitive body is exposed while the first comparison and control circuit performs said comparison and said control of light quantity.

2 more elements

An optical printer which forms images on a photosensitive body by the exposure of the photosensitive body, comprising:

an optical head which includes a light source, an optical shutter to control transmission and blockage of light from said light source, and a first photosensor to detect light and output a corresponding signal;
a reference value storing circuit for storing a value of a voltage;
and
a first comparison and control circuit for comparing the voltage of the signal outputted from said first photosensor with the value stored in said reference value storing circuit to control a quantity of light from said light source, wherein
said first photosensor carries out calibration of said light of said light source by detecting the light which was irradiated from said light source but has not yet passed said optical shutter to output the light,
said optical printer is of a line scanning type which forms images on said photosensitive body by irradiating each line with light and scans a prescribed number of lines, and
said optical shutter is a liquid crystal shutter.

4 more elements

Dependencies are inferred from the claim text.

Calibration apparatus for light emitting elements in an optical printer

Life of this patent

Calibration apparatus for light emitting elements in an optical printer

Life of this patent

Abstract

Claims24