Provided is a technique for allowing a user to easily check the status of an image scanning apparatus. An image scanning apparatus is configured to transmit original document image data by storing, sequentially in a buffer, line data obtained by line-by-line scanning of an original document and transmitting the stored line data to a host computer sequentially line by line, and includes a control unit configured to perform control to transmit original document image data including notification image data to the host computer in a case where it is detected that the apparatus status of the image scanning apparatus is not normal during processing executed in response to a scan command received from the host computer, the notification image data being a notification of an error occurrence.

Provided is a technique for allowing a user to easily check the status of an image scanning apparatus. An image scanning apparatus is configured to transmit original document image data by storing, sequentially in a buffer, line data obtained by line-by-line scanning of an original document and transmitting the stored line data to a host computer sequentially line by line, and includes a control unit configured to perform control to transmit original document image data including notification image data to the host computer in a case where it is detected that the apparatus status of the image scanning apparatus is not normal during processing executed in response to a scan command received from the host computer, the notification image data being a notification of an error occurrence.

An image reading apparatus includes a transparent member, reading portion, a pattern, and a processor. The processor extracts a frequency component in an image of the pattern read by the reading portion in a period in which the reading portion reads an image of an original placed on the transparent member while moving in a first direction. The processor calculates a frequency component from the extracted frequency component in another position different from the position, in which the pattern is provided, with respect to the second direction crossing the first direction. The processor converts the calculated frequency component in the above-described another position into a time-series component. The processor corrects an image corresponding to the above-described another position by using the converted time-series component in the above-described another position.

An image reading apparatus includes a transparent member, reading portion, a pattern, and a processor. The processor extracts a frequency component in an image of the pattern read by the reading portion in a period in which the reading portion reads an image of an original placed on the transparent member while moving in a first direction. The processor calculates a frequency component from the extracted frequency component in another position different from the position, in which the pattern is provided, with respect to the second direction crossing the first direction. The processor converts the calculated frequency component in the above-described another position into a time-series component. The processor corrects an image corresponding to the above-described another position by using the converted time-series component in the above-described another position.

A print data editing device is configured to perform: editing print data such that when dots constituting an input image represented by the print data are compared by units of columns before and after the editing, a coincidence is maximized when an image of each column in the input image after the editing is the same position as an image of the corresponding column in the input image before the editing or is shifted by a corresponding shift amount in a sub-scanning direction relative to the image of the corresponding column in the input image before the editing. An absolute value of at least one of shift amounts for columns in the input image after the editing is one dot or greater. An absolute difference value for any two neighboring columns in a main scanning direction in the input image after the editing is one dot or less.

An image is read from a recording medium via first and second optical imaging systems disposed such that respective reading regions partially overlap each other in a principal scanning direction on a reading surface. A sum of distances over which first and second images captured by the first and second optical imaging systems, respectively, are displaced in the principal scanning direction with respect to a reference point included in a region in which the reading regions overlap each other is calculated. First and second distances, over which the first and second images are displaced in the principal scanning direction, respectively, are calculated using the sum and first and second reading angles at which the first and second optical imaging systems, respectively, read the reference point. Positions of the first image and the second image in the principal scanning direction are corrected using the first distance and the second distance, respectively.

An image is read from a recording medium via first and second optical imaging systems disposed such that respective reading regions partially overlap each other in a principal scanning direction on a reading surface. A sum of distances over which first and second images captured by the first and second optical imaging systems, respectively, are displaced in the principal scanning direction with respect to a reference point included in a region in which the reading regions overlap each other is calculated. First and second distances, over which the first and second images are displaced in the principal scanning direction, respectively, are calculated using the sum and first and second reading angles at which the first and second optical imaging systems, respectively, read the reference point. Positions of the first image and the second image in the principal scanning direction are corrected using the first distance and the second distance, respectively.

In an image-reading device, a counting unit counts a number of clock cycles of a spread-spectrum clock as a counter value. A correcting unit corrects one of the counter value and a reference clock cycle number based on a phase detected by the phase detecting unit when the counting unit counts. A comparing unit compares the counter value and the reference clock cycle number and determines whether the counter value and the reference clock cycle number satisfy a prescribed relationship. A time length setting unit sets a length of at least one of a reading time and an irradiation time based on: a timing when the counting unit starts counting to set the time length; and a timing when the comparing unit determines that the compared values satisfy the prescribed relationship, such that the time length set by the time length setting unit remains constant.

In an image-reading device, a counting unit counts a number of clock cycles of a spread-spectrum clock as a counter value. A correcting unit corrects one of the counter value and a reference clock cycle number based on a phase detected by the phase detecting unit when the counting unit counts. A comparing unit compares the counter value and the reference clock cycle number and determines whether the counter value and the reference clock cycle number satisfy a prescribed relationship. A time length setting unit sets a length of at least one of a reading time and an irradiation time based on: a timing when the counting unit starts counting to set the time length; and a timing when the comparing unit determines that the compared values satisfy the prescribed relationship, such that the time length set by the time length setting unit remains constant.

An optical writing device and an image forming apparatus incorporating the optical writing device. The optical writing device includes two or more light sources, a pixel clock generator to measure a scanning speed of one of the two or more light sources and generate a pixel clock of a cycle corrected according to the measured scanning speed, a pulse data generation and output unit to generate pulse width data and shift data for the pixel clock generated by the pixel clock generator to output the generated pulse width data and the generated shift data for each one of the two or more light sources, and a plurality of image pulse generation and output units to generate an image pulse. In the optical writing device, the plurality of image pulse generation and output units are supplied with the pixel clock in common.