An image reading apparatus which reads an image includes a first pixel that includes a first light receiving element which performs photoelectric conversion; a second pixel that includes a second light receiving element which performs photoelectric conversion; a first reading circuit that includes a first capacitor which is electrically connected to the first pixel and a first amplifier having an input terminal which is electrically connected to the first capacitor; a second reading circuit that includes a second capacitor which is electrically connected to the second pixel, a second amplifier, and a first switch which switches whether or not to electrically connect the second capacitor to an input terminal of the second amplifier; and a second switch that switches whether or not to electrically connect a first node between the first capacitor and the first amplifier to a second node between the second capacitor and the second amplifier.

A circuit that includes: a photodiode configured to absorb photons and to generate photo-carriers from the absorbed photons; a first MOSFET transistor that includes: a first channel terminal coupled to a first terminal of the photodiode and configured to collect a portion of the photo-carriers generated by the photodiode; a second channel terminal; and a gate terminal coupled to a first control voltage source; a first readout circuit configured to output a first readout voltage; a second readout circuit configured to output a second readout voltage; and a current-steering circuit configured to steer the photo-carriers generated by the photodiode to one or both of the first readout circuit and the second readout circuit.

A circuit that includes: a photodiode configured to absorb photons and to generate photo-carriers from the absorbed photons; a first MOSFET transistor that includes: a first channel terminal coupled to a first terminal of the photodiode and configured to collect a portion of the photo-carriers generated by the photodiode; a second channel terminal; and a gate terminal coupled to a first control voltage source; a first readout circuit configured to output a first readout voltage; a second readout circuit configured to output a second readout voltage; and a current-steering circuit configured to steer the photo-carriers generated by the photodiode to one or both of the first readout circuit and the second readout circuit.

A method for correcting in-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured in-track position for each of the alignment marks. The measured in-track positions for the alignment marks are compared to reference positions to determine measured in-track position errors. An in-track position correction function is determined responsive to the measured in-track position errors, wherein the in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

A circuit that includes: a photodiode configured to absorb photons and to generate photo-carriers from the absorbed photons; a first MOSFET transistor that includes: a first channel terminal coupled to a first terminal of the photodiode and configured to collect a portion of the photo-carriers generated by the photodiode; a second channel terminal; and a gate terminal coupled to a first control voltage source; a first readout circuit configured to output a first readout voltage; a second readout circuit configured to output a second readout voltage; and a current-steering circuit configured to steer the photo-carriers generated by the photodiode to one or both of the first readout circuit and the second readout circuit.

A method for correcting in-track position errors in a digital printing system having a linear printhead includes printing a test target including a plurality of alignment marks. A data processing system is used to automatically analyze a captured image of the printed test target to determine a measured in-track position for each of the alignment marks. The measured in-track positions for the alignment marks are compared to reference positions to determine measured in-track position errors. An in-track position correction function is determined responsive to the measured in-track position errors, wherein the in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

A color printer includes image forming assemblies, a contact image sensor (CIS) and a processor. The image forming assemblies generate image forming substances, which have different colors and are transfer-printed onto a belt assembly. The CIS detects the image forming substances on the belt assembly passing by the CIS to obtain a detected result. The processor electrically connected to the CIS receives the detected result and determines whether an arrangement of the image forming substances with a same color satisfies a predetermined angle of the CIS according to the detected result.

A circuit that includes: a photodiode configured to absorb photons and to generate photo-carriers from the absorbed photons; a first MOSFET transistor that includes: a first channel terminal coupled to a first terminal of the photodiode and configured to collect a portion of the photo-carriers generated by the photodiode; a second channel terminal; and a gate terminal coupled to a first control voltage source; a first readout circuit configured to output a first readout voltage; a second readout circuit configured to output a second readout voltage; and a current-steering circuit configured to steer the photo-carriers generated by the photodiode to one or both of the first readout circuit and the second readout circuit.

A circuit that includes: a photodiode configured to absorb photons and to generate photo-carriers from the absorbed photons; a first MOSFET transistor that includes: a first channel terminal coupled to a first terminal of the photodiode and configured to collect a portion of the photo-carriers generated by the photodiode; a second channel terminal; and a gate terminal coupled to a first control voltage source; a first readout circuit configured to output a first readout voltage; a second readout circuit configured to output a second readout voltage; and a current-steering circuit configured to steer the photo-carriers generated by the photodiode to one or both of the first readout circuit and the second readout circuit.

An image reading apparatus includes a reader, a reference plate, a transportation mechanism, and a processor. The reader reads a line image in a main scanning direction. The transportation mechanism transports the reader in a sub-scanning direction. The processor reads a first number of line images across a first line width in the sub-scanning direction from the reference plate, on each block that results from division in the sub-scanning direction, which is performed by causing the reader to be transported using the transportation mechanism. Thus, the processor detects foreign matter on each block that is set to be on the reference plate, selects a reading block for reading shading data, from a block on which the foreign matter is not present, and reads the first number of line images, as the shading data, across a second line width that is narrower than the first line width.