A light source includes a light emitting element, and an optical system that directs light output from the light emitting element to a surface of a photosensitive member. An irradiation amount of light for forming a second electrostatic latent image is larger than an irradiation amount of light for forming a first electrostatic latent image. A position at which a propagation efficiency of light peaks in a scanning direction of the light is located between a center of an image height of the optical system and a surface area in which the second electrostatic latent image is formed out of the surface of the photosensitive member.

An image forming apparatus includes an image forming portion, and a bonding portion including a pressurizing member and configured to bond sheets together. The bonding portion is configured to, in a state in which a succeeding sheet is stacked on a sheet stack that has been bonded in a previous bonding operation, perform a next bonding operation to bond a first surface of an uppermost sheet of the bonded sheet stack to a second surface of the succeeding sheet opposing the first surface. An amount of bonding toner that the image forming portion applies on the first surface per unit area of the first surface is smaller than an amount of the bonding toner that the image forming portion applies on the second surface per unit area of the second surface.

An image forming apparatus includes: a scanning unit configured to form latent images in a first region and in a second region of the photoreceptor; and a control unit configured to control a light emission luminance of the scanning unit. The control unit is further configured to set the light emission luminance of the scanning unit to a first light emission luminance when scanning of the first region is started, and set the light emission luminance of the scanning unit to a second light emission luminance higher than the first light emission luminance when scanning of the second region is started, and to decrease the light emission luminance of the scanning unit while the second region is being scanned, in a case where the second region is an upstream side of the first region in the scanning direction.

A booklet forming device includes a sheet support portion, and a bonding unit including a pressurizing member and configured to form a bonding layer. In a case of forming a first booklet including a first number of sheets, the bonding unit is operated under a first operation condition so that a thickness of the bonding layer positioned closest to the pressurizing member in the first booklet becomes a first thickness. In a case of forming a second booklet including a second number of sheets more than the first number of sheets, the bonding unit is operated under a second operation condition different from the first operation condition so that the thickness of the bonding layer positioned closest to the pressurizing member in the second booklet becomes a second thickness larger than the first thickness.

An image forming apparatus at least comprising: first image forming means for forming a first adhesive layer of a first toner on a sheet; and second image forming means for forming a second adhesive layer of a second toner on the first adhesive layer, adhesive image patterns are formed from the first and the second adhesive layer, the image forming apparatus further comprising specific booklet bonding means, wherein at least both the first and the second adhesive layer are formed on one of a first sheet and a second sheet that face each other in the sheet bundle, at least the first adhesive layer is formed on the other of the first sheet and the second sheet, and G1>G2 is satisfied, where G1 denotes a storage elastic modulus of the first toner, and G2 denotes a storage elastic modulus of the second toner.

An image forming apparatus comprises a rotationally driven photosensitive body, a charging device that charges a surface of the photosensitive body, an exposure light source that forms an electrostatic latent image by exposing the surface of the photosensitive body to light, a developing device that forms a toner image by developing the electrostatic latent image using toner, a transfer member that transfers the toner image to a sheet, a first memory that stores a cumulative image formation amount for each one of N exposure regions, and a control circuit that controls the exposure light source.

A sheet thermocompression apparatus for bonding a plurality of the sheets to one another, and configured to be compatible with the sheets with a plurality of prescribed sizes. The apparatus includes a loading portion to be loaded with the bundle of sheets each including the adhesion layer formed thereon and a thermocompression unit. The thermocompression unit includes (i) a pressing member pressing the bundle of sheets loaded on the loading portion in a loading direction of the sheets, a longitudinal direction of the pressing member is a direction along one edge of the sheets loaded on the loading portion, (ii) a heating source heating the pressing member, and (iii) a temperature measuring sensor arranged at a position not overlapping a minimum sheet with a minimum size of the prescribed sizes loaded on the loading portion in the loading direction, and detects a temperature of the heating source.

A method for controlling an image forming apparatus includes performing image formation on a sheet using a recording material, executing sheet processing for binding a plurality of sheets using the recording material, and storing a history of the image formation and a history of the sheet processing.

A sheet processing apparatus includes a center folder, a back-crimp binder, and circuitry. The center folder performs a center-folding process to form a fold portion on a sheet bundle including multiple sheets. The back-crimp binder includes a back-portion former and a crimp binder. The back-portion former forms a back portion of the fold portion on the sheet bundle subjected to the center-folding process. The crimp binder performs a crimp-binding process on the back portion of the sheet bundle subjected to the center-folding process. The circuitry is to cause the back-crimp binder to form a crimp mark parallel to the fold portion on the back portion of the sheet bundle.

A sheet processing apparatus includes: a center-folder to perform a center-folding process on a sheet bundle including multiple sheet materials; a back-crimp binder to: form a back portion on the sheet bundle subjected to the center-folding process; and perform a crimp-binding process on the back portion; and a controller configured to: cause the center-folder to perform the center-folding process; and cause the back-crimp binder to perform the crimp-binding process on the back portion while forming the back portion on the sheet bundle in the crimp-binding process.