Exposure head and image-forming apparatus

An exposure head, which exposes a rotating photosensitive member, comprising:

• a plurality of light emitting element array chips arranged in a staggered manner around an imaginary line along a rotation axis of the photosensitive member;
• and
• a circuit board on which the plurality of light emitting element array chips are mounted, the plurality of light emitting element array chips including a first light emitting element array chip and a second light emitting element array chip arranged in a position different from a position of the first light emitting element array chip, each of the first light emitting element array chip and the second light emitting element array chip including:
• a light emitting area including a plurality of light emitting portions;
• and
• a sealing material for covering the light emitting area,
• wherein each of the first light emitting chip and the second light emitting chip includes a first long side and a second long side, and wherein a first distance from a first side to one long side of the sealing area which is proximate to the first side is shorter than a second distance from a second side to another long side of the sealing area which is proximate to the second side, and
• wherein a third distance from the first side to one long side of the light emitting area which is proximate to the first side is shorter than a fourth distance from the second side to another long side of the light emitting area which is proximate to the second side, and
• wherein a distance from the one long side of the sealing area to the one long side of the light emitting area is shorter than a distance from the another long side of the sealing area to the another long side of the light emitting area, and
• wherein a distance from the first side of the first light emitting chip to the imaginary line is shorter than a distance from the second side of the first light emitting chip to the imaginary line, and
• wherein a distance from the first side of the second light emitting chip to the imaginary line is shorter than a distance from the second side of the second light emitting chip to the imaginary line.

An image forming apparatus comprising:

• a photosensitive drum;
• a charger configured to uniformly charge a surface of the photosensitive drum;
• an exposure head configured to expose the surface of the photosensitive drum with light in accordance with an image signal to form an electrostatic latent image, the exposure head including:
• a plurality of light emitting element array chips arranged in a staggered manner around an imaginary line along a rotation axis of the photosensitive drum;
• a circuit board on which the plurality of light emitting element array chips are mounted, the plurality of light emitting element array chips including a first light emitting element array chip and a second light emitting element array chip arranged in a position different from a position of the first light emitting element array chip, each of the first light emitting element array chip and the second light emitting element array chip including:
• a light emitting area including a plurality of light emitting portions;
• and
• a sealing material for covering a light emitting face of the light emitting area and a side face of the light emitting area,
• wherein each of the first light emitting chip and the second light emitting chip includes a first long side and a second long side, and
• wherein a first distance from a first side to one long side of the sealing area which is proximate to the first side is shorter than a second distance from a second side to another long side of the sealing area which is proximate to the second side, and
• wherein a third distance from the first side to one long side of the light emitting area which is proximate to the first side is shorter than a fourth distance from the second side to another long side of the light emitting area which is proximate to the second side;
• wherein a distance from the one long side of the sealing area to the one long side of the light emitting area is shorter than a distance from the another long side of the sealing area to the another long side of the light emitting area, and
• wherein a distance from the first side of the first light emitting chip to the imaginary line is shorter than a distance from the second side of the first light emitting chip to the imaginary line, and
• wherein a distance from the first side of the second light emitting chip to the imaginary line is shorter than a distance from the second side of the light emitting chip to the imaginary line;
• a developing device configured to develop the electrostatic latent image with toner to form a toner image;
• a transfer device configured to transfer the toner image onto a recording medium;
• and
• a fixing device configured to apply heat and pressure to the toner image to fix the toner image to the recording medium.