A pixel clock generating device includes a high-frequency clock generator, a comparer, a pixel clock generator, and a value switcher. The high-frequency clock generator is configured to generate a high-frequency clock. The comparer is configured to measure a time interval between a leading-end synchronizing signal and a trailing-end synchronizing signal in a main scanning and calculate an error between the time interval and a target value. The pixel clock generator is configured to generate a pixel clock based on the high-frequency clock and a pixel clock frequency and correct the pixel clock based on the error. The value switcher, including a plurality of groups of values with which the pixel clock is generated, is configured to switch between the plurality of groups of values according to a switching signal after the trailing-end synchronizing signal is inputted, the comparer calculates the error, and the pixel clock generator corrects the pixel clock.

In one embodiment, a control method for an image processing apparatus including a reading unit configured to read a document image and a printing unit configured to print the document image read by the reading unit is provided. The control method includes detecting an error in process of reading by the reading unit, causing the reading unit to perform reread processing for rereading the document image based on the error being detected, and refraining, in a case where the image processing apparatus operates in a mode in which the printing unit starts printing without waiting for the reading unit to complete reading a document image, from causing the reading unit to perform the reread processing based on the error being detected.

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.

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.

An image forming apparatus, including: an image signal generating portion configured to generate an image signal as bit data obtained by splitting image data by a predetermined integer value for each pixel; a first storage portion configured to store a profile indicating magnification correction data for each of a plurality of regions in a main scanning direction; and a second storage portion configured to store a partial magnification granularity being a size of a processing unit used for splitting a partial magnification correction start value, wherein the image signal generating portion calculates a split region boundary address indicating a main scanning position at which a scanning region on the surface of a photosensitive member to be scanned by a light beam is split in the main scanning direction for each partial magnification granularity based on the partial magnification correction start value extracted from the profile and the partial magnification granularity.

A first reference portion has a lower surface of a first color. A second reference portion is adjacent to the first reference portion in a first direction and has a lower surface of a second color. A data processing portion executes a color determination process of determining whether one or more reference pixel data of a reference area in line image data is data of the first color or the second color. A control device sequentially selects a plurality of drive operations from a plurality of trial drive operations and causes the unit drive device to execute the plurality of drive operations, thereby positioning a scanning unit at a home position. When causing the unit drive device to execute the plurality of drive operations, the control device outputs, to the unit drive device, a speed command signal of a different level according to a moving distance of the scanning unit.

A first reference portion has a lower surface of a first color. A second reference portion is adjacent to the first reference portion in a first direction and has a lower surface of a second color. A data processing portion executes a color determination process of determining whether one or more reference pixel data of a reference area in line image data is data of the first color or the second color. A control device sequentially selects a plurality of drive operations from a plurality of trial drive operations and causes the unit drive device to execute the plurality of drive operations, thereby positioning a scanning unit at a home position. When causing the unit drive device to execute the plurality of drive operations, the control device outputs, to the unit drive device, a speed command signal of a different level according to a moving distance of the scanning unit.

Microscope slide scanner. In an embodiment the microscope slide scanner comprises a single enclosure unit that includes at least one objective lens, at least one line scan camera, at least one communication port, and at least one processor. The line scan camera may be configured to capture image data of a sample as a plurality of image stripes via the objective lens. The communication port provides communication over a network. The processor may align the plurality of image stripes into a contiguous image of at least a portion of the sample, and executes a web server that provides an operator interface over the network to one or more remote devices.

In accordance with an embodiment, an image reading apparatus comprises a carriage, a stepping motor and a processor. The carriage acquires an image. The stepping motor moves the carriage. The processor outputs a first clock signal for driving the stepping motor if a present position of the carriage is unknown and outputs a second clock signal, of which a frequency is higher than that of the first clock signal, for driving the stepping motor if the present position of the carriage can be recognized.

In accordance with an embodiment, an image reading apparatus comprises a carriage, a stepping motor and a processor. The carriage acquires an image. The stepping motor moves the carriage. The processor outputs a first clock signal for driving the stepping motor if a present position of the carriage is unknown and outputs a second clock signal, of which a frequency is higher than that of the first clock signal, for driving the stepping motor if the present position of the carriage can be recognized.