A printing system includes: a first printing unit that performs printing on a medium on the basis of first printing data; a first inventing unit that is located downstream from the first printing unit in a transportation direction specific to the medium and performs an inverting operation that is an operation of inverting front and back sides of the medium; a second printing unit that is located downstream from the first inverting unit in the transportation direction and performs printing on the medium on the basis of second printing data; and a control unit that determines whether the first inverting unit needs to perform the inverting operation, on the basis of whether the second printing data indicates a printing page for the front or back side of the medium.

An image reading apparatus includes an imaging device, a first communication device capable of communicating at a first communication speed according to a first communication protocol, a second communication device capable of communicating at a second communication speed lower than the first communication speed according to a second communication protocol different from the first communication protocol, a first processor to separately transmit a first image acquired by imaging a first surface of a medium by the imaging device, and a second image acquired by imaging a second surface of the medium by the imaging device, via the first communication device, and a second processor to transmit a combined image acquired by combining the first image and the second image via the second communication device.

An image reader includes a first judging section which judges whether a newly captured image is an image obtained by page-turning of a book to a destination position of the page; a temporary storage section which temporarily stores the newly captured image as a previous captured image when it is judges that the newly captured image is not an image obtained by page-turning to a destination position; a second judging section which, prior to temporarily storing the newly captured image as a previous captured image, judges whether, based on a latest image temporarily stored as a previous captured image and the newly captured image to be temporarily stored, the latest captured image and the newly captured image are an image of same pages; and a determining section which determines the latest captured image as a storage target when it is judged that the latest captured image and the newly captured image are not an image of a same page.

An image reading apparatus to read a sheet being conveyed includes a memory and a reading device to read one side of the sheet in units of a line area orthogonal to a conveyance direction of the sheet. A read image of a first region corresponding to a leading edge side of the sheet in the conveyance direction is stored into the memory. A read image of a second region subsequent to the first region is not stored. A read image of a third region subsequent to the second region and corresponding to a trailing edge side of the sheet in the conveyance direction is stored in the memory. Each read image is an image read by the reading device. Predetermined processing is performed based on the read image of the first region and the read image of the third region stored in the memory.

An image reading apparatus includes an imaging device, a first communication device capable of communicating at a first communication speed according to a first communication protocol, a second communication device capable of communicating at a second communication speed lower than the first communication speed according to a second communication protocol different from the first communication protocol, a first processor to separately transmit a first image acquired by imaging a first surface of a medium by the imaging device, and a second image acquired by imaging a second surface of the medium by the imaging device, via the first communication device, and a second processor to transmit a combined image acquired by combining the first image and the second image via the second communication device.

An image processing apparatus includes a size acquisition unit and a decision unit. The size acquisition unit acquires first size information indicating a first sheet size of a first sheet surface read by an image reading unit. The decision unit decides second image information indicating a second image size of a second image to be stored of a second sheet surface different from the first sheet surface based on first image information indicating a first image size of a first image to be stored based on the first size information.

A printing system includes: a first printing unit that performs printing on a medium on the basis of first printing data; a first inventing unit that is located downstream from the first printing unit in a transportation direction specific to the medium and performs an inverting operation that is an operation of inverting front and back sides of the medium; a second printing unit that is located downstream from the first inverting unit in the transportation direction and performs printing on the medium on the basis of second printing data; and a control unit that determines whether the first inverting unit needs to perform the inverting operation, on the basis of whether the second printing data indicates a printing page for the front or back side of the medium.

An image reading apparatus to read a sheet being conveyed includes a memory and a reading device to read one side of the sheet in units of a line area orthogonal to a conveyance direction of the sheet. A read image of a first region corresponding to a leading edge side of the sheet in the conveyance direction is stored into the memory. A read image of a second region subsequent to the first region is not stored. A read image of a third region subsequent to the second region and corresponding to a trailing edge side of the sheet in the conveyance direction is stored in the memory. Each read image is an image read by the reading device. Predetermined processing is performed based on the read image of the first region and the read image of the third region stored in the memory.

An image processing apparatus includes a size acquisition unit and a decision unit. The size acquisition unit acquires first size information indicating a first sheet size of a first sheet surface read by an image reading unit. The decision unit decides second image information indicating a second image size of a second image to be stored of a second sheet surface different from the first sheet surface based on first image information indicating a first image size of a first image to be stored based on the first size information.

An image forming apparatus includes an image forming section and a controller. The image forming section forms an image on a first sheet or a second sheet. The controller controls the image forming section. The first sheet is a blank sheet. The second sheet is a reused sheet. The controller refers to reference images each belonging to any of a plurality of categories to determine whether or not the image belongs to any of the categories. The controller directs the image forming section to form the image on the second sheet when determining that the image does not belong to any of the categories. The controller directs the image forming section to form the image on the first sheet and stores the image as a reference image when determining that the image belongs to any of the categories.