Exposure device having a plurality of first and second light emitting elements, LED head as the exposure device, image forming apparatus including the exposure device, and image reading apparatus

An exposure device, comprising:

• a first light emitting element substrate including a plurality of first light emitting elements arranged at an arrangement interval T in a longitudinal direction of the first light emitting element substrate;
• a second light emitting element substrate including a part in the longitudinal direction that overlaps with a part of the first light emitting element substrate so as to form an overlapping region;
• and
• a base on which the first light emitting element substrate and the second light emitting element substrate are placed;
• wherein the first light emitting element substrate and the second light emitting element substrate are shifted from each other in a direction perpendicular to the longitudinal direction;
• wherein the second light emitting element substrate includes a plurality of second light emitting elements arranged in the longitudinal direction, the second light emitting elements being arranged at the arrangement interval T at least outside the overlapping region;
• wherein when an interval between two of the second light emitting elements of the second light emitting element substrate disposed in the overlapping region is expressed as a specified interval TS, the specified interval TS and the arrangement interval T satisfy the following relationship:
• T≤TS≤2T,
• wherein the first light emitting element substrate has a fixed end portion fixed to the base, and a movable end portion movably placed on the base;
• wherein the second light emitting element substrate has a fixed end portion fixed to the base, and a movable end portion movably placed on the base;
• and
• wherein the movable end portion of the first light emitting element substrate and the fixed end portion of the second light emitting element substrate are located in the overlapping region.

An exposure device, comprising:

• a first light emitting element substrate including a plurality of first light emitting elements arranged at an arrangement interval T in a longitudinal direction of the first light emitting element substrate;
• and
• a second light emitting element substrate including a part in the longitudinal direction that overlaps with a part of the first light emitting element substrate so as to form an overlapping region,
• wherein the first light emitting element substrate and the second light emitting element substrate are shifted from each other in a direction perpendicular to the longitudinal direction;
• wherein the second light emitting element substrate includes a plurality of second light emitting elements arranged in the longitudinal direction, the second light emitting elements being arranged at the arrangement interval T at least outside the overlapping region;
• wherein when an interval between two of the second light emitting elements of the second light emitting element substrate disposed in the overlapping region is expressed as a specified interval TS, the specified interval TS and the arrangement interval T satisfy the following relationship:
• T≤TS≤2T;
• and
• wherein the light emission is switched between the first light emitting element of the first light emitting element substrate disposed in the overlapping region and the second light emitting element of the second light emitting element substrate disposed in the overlapping region.

An image reading apparatus, comprising:

• a first light receiving element substrate including a plurality of first light receiving elements arranged at an arrangement interval T in a longitudinal direction of the first light receiving element substrate;
• and
• a second light receiving element substrate including a part in the longitudinal direction that overlaps with a part of the first light receiving element substrate so as to form an overlapping region,
• wherein the first light receiving element substrate and the second light receiving element substrate are shifted from each other in a direction perpendicular to the longitudinal direction;
• wherein the second light receiving element substrate includes a plurality of second light receiving elements arranged in the longitudinal direction, the second light receiving elements being arranged at the arrangement interval T at least outside the overlapping region;
• wherein when an interval between two of the second light receiving elements of the second light receiving element substrate disposed in the overlapping region is expressed as a specified interval TS, the specified interval TS and the arrangement interval T satisfy the following relationship:
• T≤TS≤2T;
• and
• wherein a displacement amount ΔT is defined by ΔT=TS−T, and the displacement amount ΔT is smaller than or equal to 10 μm.

An image reading apparatus, comprising:

• a first light receiving element substrate including a plurality of first light receiving elements arranged at an arrangement interval T in a longitudinal direction of the first light receiving element substrate;
• a second light receiving element substrate including a part in the longitudinal direction that overlaps with a part of the first light receiving element substrate so as to form an overlapping region;
• and
• a base on which the first light receiving element substrate and the second light receiving element substrate are placed;
• wherein the first light receiving element substrate and the second light receiving element substrate are shifted from each other in a direction perpendicular to the longitudinal direction;
• wherein the second light receiving element substrate includes a plurality of second light receiving elements arranged in the longitudinal direction, the second light receiving elements being arranged at the arrangement interval T at least outside the overlapping region;
• wherein when an interval between two of the second light receiving elements of the second light receiving element substrate disposed in the overlapping region is expressed as a specified interval TS, the specified interval TS and the arrangement interval T satisfy the following relationship:
• T≤TS≤2T,
• wherein the first light receiving element substrate has a fixed end portion fixed to the base, and a movable end portion movably placed on the base;
• wherein the second light receiving element substrate has a fixed end portion fixed to the base, and a movable end portion movably placed on the base;
• and
• wherein the movable end portion of the first light receiving element substrate and the fixed end portion of the second light receiving element substrate are located in the overlapping region.

An image reading apparatus, comprising:

• a first light receiving element substrate including a plurality of first light receiving elements arranged at an arrangement interval T in a longitudinal direction of the first light receiving element substrate;
• and
• a second light receiving element substrate including a part in the longitudinal direction that overlaps with a part of the first light receiving element substrate so as to form an overlapping region, wherein the first light receiving element substrate and the second light receiving element substrate are shifted from each other in a direction perpendicular to the longitudinal direction;
• wherein the second light receiving element substrate includes a plurality of second light receiving elements arranged in the longitudinal direction, the second light receiving elements being arranged at the arrangement interval T at least outside the overlapping region;
• wherein when an interval between two of the second light receiving elements of the second light receiving element substrate disposed in the overlapping region is expressed as a specified interval TS, the specified interval TS and the arrangement interval T satisfy the following relationship:
• T≤TS≤2T;
• and
• wherein the light emission is switched between the first light receiving element of the first light receiving element substrate disposed in the overlapping region and the second light receiving element of the second light receiving element substrate disposed in the overlapping region.