Disclosed is a blade for a saddle folding unit that can saddle-fold a sheet. At the edge of a folding side of the sheet in the blade, a protrusion portion protruding in a pushing direction of the blade is provided.

A sheet processing apparatus, including: a rotary member pair configured to nip a sheet conveyed in a conveyance path and rotate to fold the sheet; and a guide portion provided between one rotary member of the rotary member pair and the conveyance path, the one rotary member including: a first part; and a second part, wherein a first distance between the first part and a rotary shaft center of the one rotary member is greater than a second distance between the second part and the rotary shaft center, and wherein the guide portion is positioned at a first position in case that the second part is positioned at a first rotational position, and the guide portion is positioned at a second position different from the first position in a distance from the rotary shaft center in case that the second part is positioned at a second rotational position.

Examples of a method for detecting misalignment cause a printer to print a calibration pattern on a recording medium sheet. The calibration pattern includes graduated measurement scales positioned so that: when the calibration pattern is printed without misalignment on a recording medium sheet of predetermined dimensions, matching graduations of plural measurement scales in the calibration pattern are printed at respective reference locations on the recording medium sheet that correspond to corners of the recording medium sheet (or to spaced positions along a line where folding of the recording medium sheet by a folding apparatus is intended to take place). When the calibration pattern is printed with misalignment on a recording medium sheet of predetermined dimensions, non-matching graduations of the plural measurement scales are printed at the reference locations on the recording medium sheet.

An image forming device includes: a post processor that performs post processing for folding or forming crease on an adjustment sheet including a reference mark and an adjustment pattern filled in with black, across the adjustment pattern based on a predetermined reference position; an image reader that reads an image of the adjustment sheet under a condition that an orientation of the adjustment sheet is changed according to the post processing type or characteristics of the adjustment sheet which is placed on the platen so that the reference mark is in a predetermined direction; a position identifying unit that identifies a fold line or crease position based on the fold line or crease that appears in the adjustment sheet; and a position adjusting unit that adjusts a fold or crease position of the post processor based on a difference between the fold or crease position and the reference position.

A printing apparatus capable of producing a product having the optimum image layout dependent on a discharge destination even when saddle-stitching is canceled due to input of image data for sheets in excess of a limit of a saddle-stitchable number of sheets. The number of output sheets per one copy is calculated based on image data. When the number of output sheets per one copy exceeds a saddle-stitchable number of sheets, it is selected whether to perform the center folding processing on the sheets on which images are printed without performing the saddle stitching processing thereon or to perform neither the saddle stitching processing nor the center folding processing on the sheets on which images are printed.

An apparatus includes: a unit that provides an instruction on creasing and folding positions on paper set such that the distance between fold crease and fold line positions is meaningful; a unit that acquires a read image by reading paper that has been subjected to creasing and folding processes in accordance with the creasing and folding positions in an open state; a unit that analyzes the read image to detect two streaks corresponding to the fold crease and the fold line from the read image, and that specifies the position of one of the two streaks as the fold crease position and the position of the other as the fold line position on the basis of the creasing and folding positions; and a unit that outputs correction information about at least one of the creasing and folding positions such that the fold crease and fold line positions match each other.

An image forming apparatus determines whether crease processing at a plurality of portions set on the sheet includes crease processing on two, front and back surfaces of the sheet; determines, if it is determined that crease processing includes crease processing on the two surfaces of the sheet, whether a connected post-processing apparatus that performs crease processing on a sheet can perform crease processing on the two, front and back surfaces of the sheet by one feeding; and controls, if it is determined that the connected post-processing apparatus cannot perform crease processing on the two surfaces by one feeding, to change, to one of the front and back surfaces of the sheet based on attribute information of the sheet, a surface to be processed in crease processing at the plurality of portions.

A method of self-adaption adjustment for post-printing treatment including steps of S1: printing a plurality of identifiers on a paper sheet for positioning actual locations of treatment on the paper sheet; S2: detecting the identifiers on the paper sheet, and locating the actual locations to be treated according to the locations of the identifiers and/or relative locations among the identifiers; and S3: adjusting locations of treatment from a post-printing treatment mechanism to the paper sheet according to the actual locations output in step S2. A system of self-adaption adjustment for post-printing treatment including a printing module, a detection module, a treatment module, a driving module and a post-printing treatment mechanism. The method and system realize the self-adaption adjustment, which effectively solves the problems that an actual value after skewing or stretching or shrinking the actual printing content is inconsistent with a theoretical value of typesetting, thus effectively improving the production efficiency and production quality, which has favorable economic and social benefits. The method and system can be widely applied in various post-printing treatment systems.

A method of forming an image and a crease on media by an image forming system includes forming a crease formation pattern on an impression media received by an impression member. The method also includes forming the image on an image forming blanket of an intermediate transfer member by a print unit. The method also includes pressing the media against the impression member by the image forming blanket to transfer the image onto the media and to establish contact with the crease formation pattern to form the corresponding crease on the media.

An image forming apparatus includes an image forming portion, a fixing portion configured to heat the toner image formed on the sheet by the image forming portion and fix the toner image to the sheet, a folding portion configured to fold the sheet having passed through the fixing portion such that a surface of the sheet to which the powder adhesive is applied is inside, and a bonding portion configured to heat the sheet folded by the folding portion and bond the sheet by the powder adhesive. A relationship of Tmax1>Tmax2 is satisfied, where Tmax1 (? C.) is a highest temperature of the powder adhesive when being heated by the fixing portion and Tmax2 (? C.) is a highest temperature of the powder adhesive when being heated by the bonding portion.