Image density correction device and image density correction method, and image reading device and image forming apparatus

An image reading device which irradiates a document and reads an image of the document with use of a photoelectric conversion element having first and second blocks and photoelectrically converting received light reflected from the document by correcting an output signal from the photoelectric conversion element, comprising:

• first means for obtaining an absolute value of an amplitude of each of first and second output signals output from the first block of the photoelectric conversion element;
• second means for comparing the absolute values with predetermined reference values to obtain differences thereof;
• first correction means for correcting the first and second output signals on the basis of the differences obtained by the second means;
• second correction means for correcting third and fourth output signals output from the second block on the basis of the differences obtained by the second means;
• transfer means for receiving the first and second output signals corrected by the first correction means and the third and fourth output signals corrected by the second correction means, and correcting a pixel arrangement of the output signals, thereby obtaining an original output signal, and then outputting the original output signal;
• and
• processing means for processing the original output signal which is output from the transfer means and has the original pixel arrangement.

An image reading device which irradiates a document and reads an image of the document with use of a quadruplex photoelectric conversion element for dividing image data into four groups and photoelectrically converting received light reflected from the document by correcting first, second, third, and fourth output signals from the quadruplex photoelectric conversion element, comprising:

• first correction means for dividing the first output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, comparing an absolute value of the control signal with a predetermined reference value, and correcting the divided image signal to have a predetermined voltage with use of an error signal obtained by the comparison;
• second correction means for dividing the second output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, comparing an absolute value of the control signal with the error signal obtained by the first correction means as a predetermined reference value, and correcting the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction means;
• third correction means for dividing the third output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, comparing an absolute value of the control signal with the error signal obtained by the first correction means as a predetermined reference value, and correcting the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as the reference value from the first correction means;
• fourth correction means for dividing the fourth output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, comparing an absolute value of the control signal with the error signal obtained by the first correction means as a predetermined reference value, and correcting the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as the reference value from the first correction means;
• transfer means for transferring the image signal corrected by the first correction means, the image signal corrected by the second correction means, the image signal corrected by the third correction means, and the image signal corrected by the fourth correction means by which a pixel arrangements of the image signals are corrected to an original one;
• and
• processing means for processing the output signals which are transferred from the transfer means and have the original pixel arrangement.

An image forming apparatus which irradiates a document and forms an image of the document on the basis of a corrected signal output from a photoelectric conversion element having first and second blocks and photoelectrically converting received reflected light from the document, comprising:

• first means for obtaining an absolute value of an amplitude of first and second output signals output from the first block of the photoelectric conversion element;
• second means for comparing the absolute values with predetermined reference values to obtain differences thereof;
• first correction means for correcting the first and second output signals on the basis of the differences obtained by the second means;
• second correction means for correcting third and fourth output signals output from the second block on the basis of the differences obtained by the second means;
• transfer means for receiving the first and second output signals corrected by the first correction means and the third and fourth output signals corrected by the second correction means, and correcting a pixel arrangement of the output signals, thereby obtaining an original output signal, and then outputting the original output signal;
• processing means for processing the original output signal which is output from the transfer means and has the original pixel arrangement;
• and
• image forming means for forming the image on the basis of the original output signal processed by the processing means.

An image forming apparatus which irradiates a document and forms an image on the basis of corrected first, second, third, and fourth output signals from a quadruplex photoelectric conversion element dividing image data into four groups and photoelectrically converting received light reflected from the document, comprising:

• first correction means for dividing the first output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, comparing an absolute value of the control signal with a predetermined reference value, and correcting the image signal to have a predetermined voltage with use of an error signal obtained by the comparison;
• second correction means for dividing the second output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, comparing an absolute value of the control signal with the error signal obtained by the first correction means as a predetermined reference value, and correcting the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction means;
• third correction means for dividing the third output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, comparing an absolute value of the control signal with the error signal obtained by the first correction means as a predetermined reference value, and correcting the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as the reference value from the first correction means;
• fourth correction means for dividing the fourth output signal output from the quadruplex photoelectric conversion element into an image signal and, a control signal, comparing an absolute value of the control signal with the error signal obtained by the first correction means as a predetermined reference value, and correcting the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as the reference value from the first correction means;
• transfer means for transferring the image signal corrected by the first correction means, the image signal corrected by the second correction means, the image signal corrected by the third correction means, and the image signal corrected by the fourth correction means by which a pixel arrangements in the output signals are corrected to an original one;
• processing means for processing the output signals transferred from the transfer means and have the original pixel arrangement;
• and
• image forming means for forming the image on the basis of the output signal processed by the processing means.

An image density correction device, comprising:

• a photoelectric conversion element having first and second blocks, to photoelectrically convert received light;
• a first circuit which obtains an absolute value of an amplitude of each of first and second output signals output from the first block of the photoelectric conversion element;
• a second circuit which compares the absolute values with predetermined reference values to obtain differences thereof;
• a first correction circuit which corrects the first and second output signals on the basis of the differences obtained by the second circuit;
• and
• a second correction circuit which corrects third and fourth output signals from the second block on the basis of the differences obtained by the second circuit.

An image reading device which irradiates a document and reads an image of the document with use of a photoelectric conversion element having first and second blocks and photoelectrically converting received light reflected from the document by correcting an output signal from the photoelectric conversion element, comprising:

• a first circuit which obtains an absolute value of an amplitude of each of first and second output signals output from the first block of the photoelectric conversion element;
• a second circuit which compares the absolute values with predetermined reference values to obtain differences thereof;
• a first correction circuit which corrects the first and second output signals on the basis of the differences obtained by the second circuit;
• a second correction circuit which corrects third and fourth output signals output from the second block on the basis of the differences obtained by the second circuit;
• a transfer circuit which receives the first and second output signals corrected by the first correction circuit and the third and fourth output signals corrected by the second correction circuit, and corrects a pixel arrangement of the output signals, thereby obtaining an original output signal, and then outputs the original output signal;
• and
• a processor which processes the original output signal which is output from the transfer circuit and has the original pixel arrangement.

An image reading device which irradiates a document and reads an image of the document with use of a quadruplex photoelectric conversion element for dividing image data into four groups and photoelectrically converting received light reflected from the document by correcting first, second, third, and fourth output signals from the quadruplex photoelectric conversion element, comprising:

• a first correction circuit which divides the first output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with a predetermined reference value, and corrects the dividing image signal to have a predetermined voltage with use of an error signal obtained by the comparison;
• a second correction circuit which divides the second output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with the error signal obtained by the first correction circuit as a predetermined reference value, and corrects the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction circuit;
• a third correction circuit which divides the third output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with the error signal obtained by the first correction circuit as a predetermined reference value, and corrects the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction circuit;
• a fourth correction circuit which divides the fourth output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with the error signal obtained by the first correction circuit as a predetermined reference value, and corrects the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction circuit;
• a transfer circuit which transfers the image signal corrected by the first correction circuit, the image signal corrected by the second correction circuit, the image signal corrected by the third correction circuit, and the image signal corrected by the fourth correction circuit by which pixel arrangements of the image signals are corrected to an original one;
• and
• a processor which processes the output signals which are transferred from the transfer circuit and have the original pixel arrangement.

An image forming apparatus which irradiates a document and forms an image of the document on the basis of a corrected signal output from a photoelectric conversion element having first and second blocks and photoelectrically converting received reflected light from the document, comprising:

• a first circuit which obtains an absolute value of an amplitude of first and second output signals output from the first block of the photoelectric conversion element;
• a second circuit which compares the absolute values with predetermined reference values to obtain differences thereof;
• a first correction circuit which corrects the first and second output signals on the basis of the differences obtained by the second circuit;
• a second correction circuit which corrects third and fourth output signals output from the second block on the basis of the differences obtained by the second circuit;
• a transfer circuit which receives the first and second output signals corrected by the first correction circuit and the third and fourth output signals corrected by the second correction circuit, and corrects a pixel arrangement of the output signals, thereby obtaining an original output signal, and then outputs the original output signal;
• a processor which processes the original output signal which is output from the transfer circuit and has the original pixel arrangement;
• and
• an image forming circuit which forms the image on the basis of the original output signal processed by the processor.

An image reading device which irradiates a document and reads an image of the document with use of a quadruplex photoelectric conversion element for dividing image data into four groups and photoelectrically converting received light reflected from the document by correcting first, second, third, and fourth output signals from the quadruplex photoelectric conversion element, comprising:

• a first correction circuit which divides the first output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with a predetermined reference value, and corrects the dividing image signal to have a predetermined voltage with use of an error signal obtained by the comparison;
• a second correction circuit which divides the second output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with the error signal obtained by the first correction circuit as a predetermined reference value, and corrects the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction circuit;
• a third correction circuit which divides the third output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with the error signal obtained by the first correction circuit as a predetermined reference value, and corrects the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction circuit;
• a fourth correction circuit which divides the fourth output signal output from the quadruplex photoelectric conversion element into an image signal and a control signal, compares an absolute value of the control signal with the error signal obtained by the first correction circuit as a predetermined reference value, and corrects the image signal to have a predetermined voltage with use of an error signal voltage obtained by the comparison of the absolute value and the error signal output as a reference value from the first correction circuit;
• a transfer circuit which transfers the image signal corrected by the first correction circuit, the image signal corrected by the second correction circuit, the image signal corrected by the third correction circuit, and the image signal corrected by the fourth correction circuit by which pixel arrangements of the image signals are corrected to an original one;
• a processor which processes the output signals which are transferred from the transfer circuit and have the original pixel arrangement;
• and
• an image forming circuit which forms the image on the basis of the output signal processed by the processor.