An image processing apparatus includes a document table, an image reading portion, a cover portion, a presser sheet, and a sheet winding portion. The presser sheet is provided on the cover portion, and contacts the document on the document table when the cover portion is positioned at the closing position. The sheet winding portion allows a first portion of the presser sheet to extend along the document table while holding a second portion of the presser sheet in a wound state. The sheet winding portion can feed the second portion when an external force is applied to the first portion. In the cover portion, a retreat space is formed so that the first portion of the presser sheet and a portion of the second portion fed from the sheet winding portion can retreat into the retreat space.

An image reading apparatus compares a difference in luminance value between a pixel of interest in image information acquired via a reading unit and a pixel separated from the pixel of interest by a first distance with a first threshold value. Further, the image reading apparatus compares a difference in luminance value between the pixel of interest and a pixel present within a range to a pixel separated from the pixel of interest by a second distance that is larger than the first distance with a second threshold value. The image reading apparatus determines whether or not the pixel of interest is an edge pixel at an original end portion based on results of those comparisons, and determines an original size based on a result of the determination.

An image reading device includes a reading member and a skew detector. The reading member reads an image of a passing document at a read position preset in a document transport path. The skew detector detects a skew of the document by selecting one of a first skew detection mode and a second skew detection mode based on information that specifies a method for detecting the skew of the document. The first skew detection mode is a mode in which the skew of the document relative to a transport direction is detected based on an image of a leading-edge section, in the transport direction, read by the reading member. The second skew detection mode is a mode in which the skew of the document relative to the transport direction is detected based on an entire image read by the reading member.

An image forming apparatus that reads a print position adjustment chart using an auto document feeder (ADF) and specifies an appropriate image reading size to include paper edges of the chart is provided.

An apparatus for defect detection in a printing system, comprising a sensor device for sensing a surface of a sheet and for generating data representing a height map of the sheet, and a processor device for processing the data from the sensor device, wherein the processor device is configured to analyze the height map to detect a presence of a deformation in the sheet. The processor device is further configured to, when a deformation is detected, to determine at least one property of the deformation, to classify the deformation with respect to a plurality of deformation classes by means of the at least one property of the deformation, and to determine a suitability of the sheet for printing based on the deformation class wherein the deformation has been classified.

An image reading apparatus which reads an image of a document is provided with a transport unit (rollers, and the like) which transports a document, a reading unit which reads a document, a double feeding detecting sensor (double feeding detecting unit) which can detect double feeding of a document, and a carrier sheet sensor (CS sensor) (sheet detecting unit) which detects a carrier sheet which is transported in a state of interposing a document between two transparent sheet portions. The CS sensor is provided at a position on the upstream side of the double feeding detecting sensor in the transport direction, in a transport direction of a document.

An image reading device includes a reading member and a skew detector. The reading member reads an image of a passing document at a read position preset in a document transport path. The skew detector detects a skew of the document by selecting one of a first skew detection mode and a second skew detection mode based on information that specifies a method for detecting the skew of the document. The first skew detection mode is a mode in which the skew of the document relative to a transport direction is detected based on an image of a leading-edge section, in the transport direction, read by the reading member. The second skew detection mode is a mode in which the skew of the document relative to the transport direction is detected based on an entire image read by the reading member.

Provided is a mechanism for setting whether to enable a shift function for shifting the sheet on which the image is printed in accordance with detection of the original.

An image forming apparatus of this invention includes abbreviated keys that realize abbreviated input of a transmission destination, an openable cover provided so as to cover the abbreviated keys, and first and second cover open/closed detection switches configured to output an open state and a closed state of the cover. When an operation of an abbreviated key is received, if the first and second cover open/closed detection switches indicate different detection results, mismatch information indicating that different output has been occurred from the first and second cover open/closed detection switches is stored in a non-volatile storage unit, and the image forming apparatus is restarted.

A sheet conveyance device includes a sheet placing portion, a guide member, a signal obtaining portion, and a notification portion. On the sheet placing portion, a sheet to be conveyed is placed. The guide member is disposed on the sheet placing portion so as to move in a width direction vertical to a sheet conveyance direction, and restricts, in the width direction, a position of the sheet on the sheet placing portion. The signal obtaining portion obtains an electric signal with a value corresponding to a position of the guide member. The notification portion, when a difference between the value and any of thresholds that are set in advance based on each sheet size in the width direction for determination of the size of the sheet, is equal to or smaller than a predetermined reference value, notifies that the sheet is separated from the guide member.