Image forming apparatus, image forming system to determine image category for using first sheet and second sheets

An image forming system, comprising:

• an image forming apparatus comprising an image forming section configured to form an image on a first sheet or a second sheet;
• and
• a server configured to exchange data with the image forming apparatus through a network, wherein
• the image forming apparatus further comprises:
• a first controller configured to control the image forming section;
• a first feed cassette configured to house the first sheet;
• and
• a second feed cassette configured to house the second sheet,
• the first sheet is a blank sheet of which the image has not been formed on either side of the first sheet,
• the second sheet is a reused sheet of which one side has been used, an image has been formed on only the one side of the second sheet, and the image has not been formed on another side of the second sheet,
• the second feed cassette houses the second sheet such that the image is to be formed on the other side on which an image has not been formed,
• the image forming section does not form the image on the one side of the second sheet but forms the image only on the other side of the second sheet,
• the server comprises a second controller configured to refer to reference images each belonging to any categories to determine whether or not the image belongs to any of the categories,
• the second controller
• determines whether or not an image determination function is active when a start signal for starting processing is inputted, the image determination function determining whether or not the image indicated by image data belongs to any of a of the categories,
• directs the image forming section to form the image indicated by the image data when determining that the image determination function is not active, and
• refers to the reference images each belonging to any of the categories to determine whether or not the image indicated by the image data belongs to any of the categories when determining that the image determination function is active,
• the second controller calculates, for each of the categories, probability that the image belongs to a category when determining whether or not the image belongs to any of the categories, and determines that the image belongs to the category as long the probability is equal to or greater than a threshold even when the image is of a different color from the reference images, of a different shape from the reference images, includes a space instead of a character relative to the reference images, or is missing a portion of a character relative to the reference images,
• the second controller, when determining that the image belongs to two or more of categories, determines that the image belongs to a category with the highest calculated probability from the two or more of the categories,
• the first controller
• directs the image forming section to form the image on the second sheet when the second controller has determined that input information inputted according to an operation of a user does not include an instruction to form the image on the first sheet and the image does not belong to any of the categories,
• directs the image forming section to form the image on the first sheet when the second controller has determined that the input information does not include an instruction to form the image on the second sheet and the image belongs to any of the categories, and
• informs the user whether the image is to be formed on the first sheet or the second sheet when the second controller has determined that the input information includes the instruction to form the image on the first sheet and the image does not belong to any of the categories,
• the second controller stores the image as a reference image to increase a number of categories when, after the user has been informed in a case where the input information includes the instruction to form the image on the first sheet and the image is determined not to belong to any of the categories, the operation of the user includes the instruction to form the image on the first sheet and the image is formed on the first sheet,
• the first controller informs the user whether the image is to be formed on the first sheet or the second sheet when the second controller has determined that the input information includes the instruction to form the image on the second sheet and the image belongs to any of the categories, and
• the second controller deletes the reference image in the category to which the image belongs to decrease the number of the categories when, after the user has been informed in a case where the input information includes the instruction to form the image on the second sheet and the image is determined to belong to any of the categories, the operation of the user includes the instruction to form the image on the second sheet and the image is formed on the second sheet.