A controller executes area defining processing for defining a middle area and two side areas, and ending processing. In a case where the document leading edge extends parallel to a main scanning direction, the controller executes the ending processing for non-skewed document. In a case where the document leading edge does not extend parallel to the main scanning direction, the controller executes the ending processing for skewed document. In which, the controller determines, in the middle area and the side areas, first, second, and third change positions, respectively, at each of which a type of a target read image data line changes from document data to document cover data, determines, based on the first change position and the second change position, whether a document has a rectangular shape, and ends the reading operation based on the third change position and the determination result as to the document shape.

An image reading apparatus includes a front-side reader, which includes a white LED configured to irradiate an original with light and a CMOS sensor configured to receive light that is reflected by the original. The front-side reader is configured to generate read data that represents a luminance value of an image on the original from the result of receiving light with the CMOS sensor. The image reading apparatus stores, in a non-volatile memory, a condition for determining whether there is a sub-scanning color shift, and uses a sub-scanning color shift detector to determine whether there is a sub-scanning color shift based on the read data obtained from the front-side reader and the condition stored in the non-volatile memory. When there is a sub-scanning color shift, the image reading apparatus corrects the sub-scanning color shift by correcting the read data with a color shift corrector.

An image forming apparatus includes a lens, first and second light sensors, a change amount detector, and a controller. The lens is in one of laser scanning systems. The first light sensor is in the one of the laser scanning systems at a position such that the scanning beam is incident on a detection surface thereof. The second light sensor is adjacent to the first light sensor and angled with respect to the first light sensor. The second light sensor is arranged such that the scanning beam is also incident on a detection surface thereof. The change amount detector is configured to detect a time interval of scanning of the first and second light sensors by the scanning beam. The controller is configured to perform an operation to calibrate the laser scanning systems when the time interval is equal to or greater than a first threshold value.

The image forming apparatus includes an image reading section and a control section. The image reading section reads a document placed on a contact glass to generate image data. The control section decides whether or not the document is present at a specified position of the contact glass and, upon deciding that the document is present at the specified position, erases handwritten images from the image data of the document read by the image reading section.

Provided is an image forming apparatus capable of accurately returning a carriage to a home position without having to turn ON a light source in the process of returning the carriage to the home position. A first reading-position-detection plate is arranged inside of a reading width of a line sensor and outside of a document-image-reading width. A second color region has a length that gradually increases in the main scanning direction as going away from the home position of the carriage. A reading-position-detecting unit detects the length in the main scanning direction of the second color region on the basis of output from the line sensor. A movement-distance-converting unit converts this length to a movement distance to the home position. A movement-control unit causes the carriage to move toward the home position just the movement distance.

An image forming apparatus including a photoconductor and a light emitting unit further includes a generating unit configured to generate correction data used for correcting a shift in the sub-scanning direction of a latent image to be formed on the photoconductor; a correcting unit configured to correct image data based on the correction data; and a control unit configured to control light emission of the light emitting unit so as to form the latent image on the photoconductor. The generating unit is configured to generate the correction data based on configuration information of the light emitting unit, information indicating time required for causing a plurality of light emitting elements to emit light, and information indicating a rotation speed of the photoconductor.

According to one embodiment, an image processing apparatus includes an input unit and a control unit. The input unit accepts a reference point of scaling for enlarging or reducing image data. The control unit performs inversion for inverting the image data according to the reference point in either or both of a main scanning direction and a sub scanning direction. The control unit performs scaling on the inverted image data generated by performing the inversion to generate scaled image data. The control unit performs inversion on the scaled image data again to generate non-inverted scaled image data.

An image forming apparatus including: a drive motor configured to rotate a rotary polygon mirror to deflect light beam; a signal generation unit configured to generate a rotation synchronous signal; and a rotation control unit configured to control a rotation speed of the rotary polygon mirror, wherein the rotation control unit executes a masking processing of masking control of the drive motor based on the rotation synchronous signal, wherein a time period of a first masking processing for a first rotation speed is shorter than a time period of a second masking processing for the second rotation speed, and wherein when the rotation speed of the rotary polygon mirror is changed from the first rotation speed to the second rotation speed, the rotation control unit switches the masking processing from the first masking processing to the second masking processing after reduction of the rotation speed of the rotary polygon mirror is started.

An image forming apparatus includes an image reading device; an image forming device including a photoconductor, a charger, an exposure device including a light-emitting element, a memory to store a first correction value for correction a light emission amount of the light-emitting element, and a driver to drive the light-emitting element, a developing device, a transfer device, and a fixing device. The image forming apparatus further includes a processor to calculate a second correction value for correcting the light emission amount, based on density data of image data of a predetermined pattern on a recording medium; calculate a third correction value for correcting the light emission amount, based on the first correction value and the second correction value; and determine, before calculating the third correction value, whether placement of the recording medium on the reading table is correct based on the density data.

Regarding an image forming apparatus for printing an input image and including a print head having a head sensor configured to sense information from the input image printed on a print medium, there is a method of determining a head sensor position parameter in the image forming apparatus. The method includes printing a first swath of the input image on the print medium and determining the head sensor position parameter by performing a sub-method. The sub-method includes capturing, via the head sensor, a target image from the printed first swath, comparing the target image to a reference image for the first swath based upon the input image, and determining the head sensor position parameter based on a relative shift between the target image and the reference image.