Bookbinding apparatus that creates book by bonding a plurality of sheets using toner

1 . A bookbinding apparatus comprising:

a photosensitive member;

a light source that forms a first electrostatic latent image corresponding to an original area and a second electrostatic latent image corresponding to an adhesive area by irradiating the photosensitive member with light;

a developing member that forms a first toner image and a second toner image by developing the first electrostatic latent image and the second electrostatic latent image using toner;

a transferring member that transfers the first toner image and the second toner image formed by the developing member to a sheet;

a fixing unit that fixes the first toner image and the second toner image on the sheet; and

a bonding unit that creates a book by bonding a plurality of sheets on which the first toner image and the second toner image have been formed with use of the second toner image,

wherein

an irradiation amount of the light for forming the second electrostatic latent image is larger than an irradiation amount of the light for forming the first electrostatic latent image,

wherein the light source includes

a light emitting element, and

an optical system that directs light output from the light emitting element to a surface of the photosensitive member,

wherein, in a scanning direction of the light that is parallel to a rotation axis of the photosensitive member, the optical system has an image height defined as a position in the scanning direction within an image formation range extending from a writing start position to a writing end position of the light on the surface of the photosensitive member, the image height representing a coordinate along the scanning direction that increases from the writing start position toward the writing end position,

wherein a peak position at which an optical efficiency of the optical system between the light emitting element and the surface of the photosensitive member peaks in the scanning direction is located between (i) a center position of the image height of the image formation range and (ii) a surface area on the photosensitive member in which the second electrostatic latent image is formed.

2 . The bookbinding apparatus according to claim 1 , wherein

the light emitting element includes a projection surface on which at least two light emission points that are each capable of projecting an optical beam have been arranged, and

wherein the peak position is located between the center position of the image height and the surface area on the photosensitive member in which the second electrostatic latent image is formed, as a result of causing the light emitting element to rotate while using a direction of a normal to the projection surface as a rotation axis.

3 . The bookbinding apparatus according to claim 1 , further comprising

a rotation mechanism that causes the light emitting element to rotate such that the peak position is located between the center position of the image height and the surface area on the photosensitive member in which the second electrostatic latent image is formed.

4 . The bookbinding apparatus according to claim 1 , further comprising

a controller that controls the light source,

wherein the controller adjusts an area in which the second electrostatic latent image is formed on the surface of the photosensitive member in accordance with a size of the sheet.

5 . The bookbinding apparatus according to claim 4 , further comprising

a generation circuit that supplies a driving current to the light emitting element,

wherein the driving current supplied to the light emitting element during the light forming the second electrostatic latent image is larger than the driving current supplied to the light emitting element during the light forming the first electrostatic latent image.

6 . The bookbinding apparatus according to claim 1 , further comprising

a generation circuit that supplies a driving current to the light emitting element; and

a correction circuit that corrects the driving current in accordance with a scanning position of the light on the surface of the photosensitive member,

wherein

during a first period in which the light forms the first electrostatic latent image, the correction circuit corrects the driving current in accordance with a scanning position of the light so as to compensate for a variation in the optical efficiency in the scanning direction of the light that is parallel to the rotation axis of the photosensitive member, and

the generation circuit generates the driving current such that the driving current supplied to the light emitting element during a second period in which the light forms the second electrostatic latent image is larger than the driving current supplied to the light emitting element during the first period.

7 . The bookbinding apparatus according to claim 6 , wherein

during the second period, the light emitting element outputs the light of an upper limit value or a rated value that has been determined for the light emitting element.

8 . The bookbinding apparatus according to claim 1 , further comprising:

an adjustment circuit that adjusts an output amount of the light output from the light emitting element to a target light amount;

a correction circuit that corrects the output amount of the light output from the light emitting element in a case where the light irradiates an image forming area on the surface of the photosensitive member in accordance with an optical efficiency of the optical system; and

a disabling circuit that, in a case where the light output from the light emitting element forms the second electrostatic latent image, disables the correction circuit so that the irradiation amount of the light for forming the second electrostatic latent image becomes larger than the irradiation amount of the light for forming the first electrostatic latent image.

9 . The bookbinding apparatus according to claim 8 , further comprising:

a power source that supplies a power source voltage to one end of the light emitting element;

a driving circuit that is included in the adjustment circuit, has one end connected to another end of the light emitting element, and generates a driving current supplied to the light emitting element;

a resistor that is included in the correction circuit and is connected between the driving circuit and a frame ground; and

a reduction circuit that is included in the correction circuit and reduces the driving current,

wherein the disabling circuit includes a switch element that inhibits an action of the reduction circuit to reduce the driving current.

10 . A bookbinding apparatus comprising:

a first photosensitive member;

a first light source that forms a first electrostatic latent image corresponding to an original area and a second electrostatic latent image corresponding to an adhesive area by irradiating the first photosensitive member with light;

a first developing member that forms a first toner image and a second toner image by developing the first electrostatic latent image and the second electrostatic latent image using toner in a first color;

a first primary transferring member that transfers the first toner image and the second toner image formed by the first developing member to an intermediate transfer member;

a second photosensitive member;

a second light source that forms a third electrostatic latent image corresponding to the original area and a fourth electrostatic latent image corresponding to the adhesive area by irradiating the second photosensitive member with light;

a second developing member that forms a third toner image and a fourth toner image by developing the third electrostatic latent image and the fourth electrostatic latent image using toner in a second color;

a second primary transferring member that transfers the third toner image and the fourth toner image formed by the second developing member to the intermediate transfer member;

a secondary transferring member that transfers the first toner image, the second toner image, the third toner image, and the fourth toner image from the intermediate transfer member to a sheet;

a fixing unit that fixes the first toner image, the second toner image, the third toner image, and the fourth toner image to the sheet; and

a bonding unit that creates a book by bonding a plurality of sheets on which the first toner image, the second toner image, the third toner image, and the fourth toner image have been formed with use of the second toner image and the fourth toner image,

wherein

an irradiation amount of the light for forming the second electrostatic latent image is larger than an irradiation amount of the light for forming the first electrostatic latent image,

wherein the first light source includes

a first light emitting element, and

a first optical system that directs light output from the first light emitting element to a surface of the first photosensitive member,

wherein, in a scanning direction of the light that is parallel to a rotation axis of the first photosensitive member, the first optical system has a first image height defined as a position in the scanning direction within a first image formation range extending from a writing start position to a writing end position of the light on the surface of the first photosensitive member, the first image height representing a coordinate along the scanning direction that increases from the writing start position toward the writing end position,

wherein a first peak position at which an optical efficiency of the first optical system between the first light emitting element and the surface of the first photosensitive member peaks in the scanning direction is located between (i) a center position of the first image height of the first image formation range and (ii) a surface area on the first photosensitive member in which the second electrostatic latent image is formed,

wherein the second light source includes

a second light emitting element, and

a second optical system that directs light output from the second light emitting element to a surface of the second photosensitive member, and

wherein, in a scanning direction of the light that is parallel to a rotation axis of the second photosensitive member, the second optical system has a second image height defined as a position in the scanning direction within a second image formation range extending from a writing start position to a writing end position of the light on the surface of the second photosensitive member, the second image height representing a coordinate along the scanning direction that increases from the writing start position toward the writing end position, and

wherein a second peak position at which an optical efficiency of the second optical system between the second light emitting element and the surface of the second photosensitive member peaks in the scanning direction is located between (i) a center position of the second image height of the second image formation range and (ii) a surface area on the second photosensitive member in which the fourth electrostatic latent image is formed.

11 . The bookbinding apparatus according to claim 10 , wherein

the first optical system and the second optical system share a single rotatable polygonal mirror,

the first light emitting element includes a first projection surface on which at least two light emission points that are each capable of projecting an optical beam have been arranged,

wherein the second light emitting element includes a second projection surface on which at least two light emission points that are each capable of projecting an optical beam have been arranged,

wherein the first peak position is located between the center position of the first image height and the surface area on the first photosensitive member in which the second electrostatic latent image is formed as a result of causing the first light emitting element to rotate while using a direction of a normal to the first projection surface as a rotation axis, and

wherein the second peak position is located between the center position of the second image height and the surface area on the second photosensitive member in which the fourth electrostatic latent image is formed as a result of causing the second light emitting element to rotate while using a direction of a normal to the second projection surface as a rotation axis.

12 . The bookbinding apparatus according to claim 11 , wherein

a rotation direction of the first light emitting element is opposite to a rotation direction of the second light emitting element.