JPS62114374A - Detecting system for deterioration in original illuminating light source - Google Patents

Abstract

PURPOSE:To inform the lowering of the average light quantity of an original illuminating light source and the increase of unevenness in the light quantity by image-forming the image of a reference reflecting plate on an image sensor, deciding the abnormality of the average level of an output signal, and informing a deterioration in the original illuminating light source. CONSTITUTION:A reference reflecting plate 30 having a uniform reflectivity is provided under an upper part cover 14. An original reading part 12 is moved to its home position, and the reflecting plate 30 is read with the reading part 12. An averaging circuit 52 and an integration circuit 56 are operated being synchronized with the scanning of an image sensor 22. The average level of a read signal for one scanning line is found by the circuit 52, and also, a difference between the read signal and the average level is found by every picture element by a difference circuit 54. The integral value of the difference for one scanning line is found by the circuit 56. Comparators 58 and 60 compare the outputs of the circuit 52 and 56 respectively with each of their threshold values, and detect the lowering of the average light quantity in an original illuminating light source 20 and the unevenness in the light quantity and inform them to a display apparatus 66.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention can be used as a stand-alone device or as a digital copier,
The present invention relates to a scanner device that is incorporated into a facsimile machine and the like. More specifically, the present invention relates to a method for detecting deterioration of a light source for illuminating a document in a scanner device that reads a document using an image sensor.

[Prior art]

Such a scanner device uses a halogen lamp or a fluorescent lamp as a light source for illuminating the original, but when used for a long period of time, such a light source for illuminating the original deteriorates and the quality of the read image deteriorates.

Many conventional scanner devices do not have a means to automatically detect such deterioration of the document illumination light source, and they determine the deterioration of the document illumination light source from the deterioration of the scanned image quality and replace the document illumination light source. It is supposed to be done. However, since it relies on human judgment, it cannot be expected to accurately detect deterioration of the light source for document illumination, and it is easy to erroneously decide when to replace it.

There are also scanner devices that have means for detecting deterioration of a light source for document illumination. The deterioration detection means detects the amount of light from the light source for illuminating the original using a phototransistor or the like, and determines the deterioration of the light source for illuminating the original based only on the detected amount of light. However, even if the light source for document illumination deteriorates and the light intensity unevenness becomes severe, if the detected light amount is equal to or greater than a specified value, it is not determined that the document has deteriorated, and the timing for replacing the document illumination light source may be incorrect.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a deterioration detection method in a scanner device that can reliably detect and notify deterioration of a document illumination light source, taking into account not only a decrease in the light amount of the document illumination light source but also an increase in light amount unevenness. be.

〔composition〕

In order to achieve such an object, the deterioration detection method of a light source for document illumination according to the present invention uses a standard reflector with uniform reflectance and an average of the output signals of the image sensor in a scanner that reads a document with an image sensor. means for determining the level, means for determining the level variation from the average level of the output signal of the image sensor, means for determining the average level and level variation determined by each of the means, and notification means responsive to a determination result by the means, means for illuminating the standard reflector with a document illumination light source to form an image of the standard reflector on the image sensor, and determining the comparison level at that time. When the determining means determines that the average level determined by is abnormal, or that the level dispersion determined by the level dispersion determining means is abnormal, the notifying means It is characterized by notifying the deterioration of the light source.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a schematic configuration diagram showing a portion of a scanner device according to the present invention directly related to document reading and a portion for detecting deterioration of a light source for illuminating the document.

In this figure, 10 is the contact I on which the original is placed.
It is made of glass, and a document reading section 12 is sunk beneath it. 14 is an upper cover, and 16 is an openable/closable cover.

The document reading unit 12 reads the document through the contact glass 10 while moving rightward in the figure from the illustrated home position. The document reading section 12 includes a light source for document illumination (for example, a halogen lamp or a fluorescent lamp) 20, an image sensor (for example, a CCD sensor) 22, mirrors 24 and 26, and an imaging lens 28.

In order to detect deterioration of the light source 20, a standard reflector 30 with uniform reflectance is provided under the upper cover 14. When the original reading unit 12 is located at the home position, the standard reflector 3o is illuminated by the light source 20, and the image of the standard reflector 30 is formed on the image sensor 22 via the mirror 24, 26 and the imaging lens 28. The image sensor 22 outputs an output signal with a level proportional to the brightness of the front surface (lower surface) of the standard reflector JQ.

Reference numeral 40 denotes an amplifier that amplifies the output signal of the image sensor 22, and the amplified output signal of the image sensor 22 (hereinafter referred to as a read signal) is converted into a digital signal by the analog/digital converter 42.

50 is a circuit for detecting and notifying deterioration of the light source 20.

This circuit 50 includes an averaging circuit 22 that calculates the average level of the read signal in one scanning line, a difference circuit 54 that calculates the difference between this average level and the level of each pixel of the read signal, and cumulatively adds the difference for one scanning line. Integration circuit 5
6. A comparator 58 that compares the output signal (average level) of the averaging circuit 52 with a first threshold; a comparator 60 that compares the output signal (level variation) of the integration circuit 56 with a second threshold;
A logical sum circuit 62 which calculates the logical sum of the output signals of the comparators 58 and 60. The output signal of this OR circuit 62 is II I II
It is comprised of a display 1ψ movement circuit 64 that lights up a display 66 to notify of deterioration of the light source.

Note that the display 66 is arranged so that its light emission can be seen from the outside of the device.

Next, the light source deterioration detection notification operation will be explained.

Prior to the original reading operation, the original reading unit 12 is first moved to the illustrated home position, and the standard reflector 30 is read by the original reading unit 12.

An averaging circuit 52 and an integrating circuit 56 operate in synchronization with the scanning of the image sensor 22. Then, the average level of the read signal for one scanning line is determined by the averaging circuit 52. Further, a difference between the read signal and the average level is determined for each pixel by a difference circuit 54, and an integrated value (level variation) of the difference is determined by an integration circuit 56 for one scanning line.

After the average level and level variation of such read signals are determined, the comparators 58, 60 are activated. and,
If the average level is above the first threshold value, it is output from the LL I I+ signal comparator 58. Similarly, if the level variation is greater than or equal to the second threshold, the signal is output from the It I II signal comparator 60 .

When the light source 20 has not deteriorated, the average light amount is sufficient and the unevenness of the light amount is small, so the average level is less than the first threshold and the level variation is also less than the second threshold.

Therefore, the display drive circuit 64 does not turn on the display 66.

When the light source 20 deteriorates, the average amount of light becomes insufficient, the unevenness of the amount of light increases, or both. In this case, the OR circuit 6
2 outputs the LL I 11 signal. As a result, the display drive circuit 64 operates to turn on the display 66 to display a display to notify the deterioration of the light source 20.

In this way, not only the overall light amount of the light source 20 is checked, but also the unevenness of the light amount is checked, so that deterioration of the light source 2o can be reliably detected and notified to the user.

Note that the means for notifying the deterioration of the light source for document illumination may be an acoustic means such as a buzzer.

The average level or level variation of the read signal may be determined for two or more scanning lines.

Further, the circuit for detecting deterioration may be realized by a program using a microprocessor.

〔effect〕

As is clear from the above description, according to the present invention, in a scanner device, deterioration of the document illumination light source can be reliably detected by taking into account not only a decrease in the average light amount of the document illumination light source but also an increase in the unevenness of the light amount. Moreover, since the deterioration is determined based on the output signal of the image sensor for document reading, it is possible to detect deterioration in accordance with the conditions of actual document reading operation rather than using a separate image sensor. It is possible to achieve effects such as lowering the parts cost by 1-.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating a document Ml capturing portion and a portion for detecting deterioration of a scanner device to which the method for detecting deterioration of a light source for document illumination according to the present invention is applied. DESCRIPTION OF SYMBOLS 10...Contact 1-Glass, 12...Document reading unit, 20...Light source for illuminating the document, 22...Image sensor, 30...Standard reflector, 50...Circuit for deterioration detection notification, 52...・Average circuit. 54...Differential circuit, 56...Integrator circuit. 58.50... Comparator, 62... OR circuit, 64
...Display drive circuit, 66...Display device. Representative Patent Attorney Makoto Suzuki

Claims (1)

[Claims] (1) In a scanner that reads a document using an image sensor, a standard reflector having a uniform reflectance, means for determining the average level of the output signal of the image sensor, and a level from the average level of the output signal of the image sensor are provided. means for determining the variation in the average level and the variation in the level obtained by each of the above-mentioned means, and a notification means for responding to the judgment result by the judgment means; A reflector is illuminated to form an image of the standard reflector on the image sensor, and at that time, the average level determined by the means for determining the average level is abnormal, or the means for determining the dispersion of the level is determined. A method for detecting deterioration of a light source for illuminating an original, characterized in that when the determining means determines that the variation in the determined level is abnormal, the notifying means notifies the deterioration of the light source for illuminating the original.