Provided are: an exposure device being configured to perform multiple exposure with the second light-emitting element array to a place exposed with the first light-emitting element array; and a controller configured to transmit a signal for controlling the exposure device, in which the exposure device sets a first pulse signal for light emission of the first light-emitting element array, based on a first delay time and a first pulse width, sets a second pulse signal for light emission of the second light-emitting element array, based on a second delay time, different from the first delay time, and a second pulse width, identical to the first pulse width, and starts and terminates light emission of each of the first light-emitting element array and the second light-emitting element array, according to the set first pulse signal and second pulse signal.

An image forming apparatus includes a housing having an opening, a cover movable between an open position and a closed position, a first photoconductive drum and a second photoconductive drum, a first exposing head having a first boss and rotatably coupled to the cover, a second exposing head having a second boss and rotatably coupled to the cover, and a cam rotatably coupled to each of the first exposing head and the second exposing head. The cam is configured to rotate each of the first exposing head and the second exposing head. The cam includes (i) a first elongated hole into which the first boss fits and extending a direction intersecting a movement direction in which the cam moves and (ii) a second elongated hole into which the second boss fits and extending in a direction intersecting the movement direction of the cam.

A light-emitting device includes: a first light- emitting unit that extends in one direction and has a first emission surface located along the one direction, the first emission surface emitting light; a second light-emitting unit that is located in the one direction with respect to the first light-emitting unit, that extends in the one direction, and that has a second emission surface located along the one direction, the second emission surface emitting light; a first cleaning unit that is capable of moving in the one direction and an opposite direction that is opposite to the one direction to clean the first emission surface; a second cleaning unit that is capable of moving in the one direction and the opposite direction to clean the second emission surface; and a transmission unit that extends from the first cleaning unit and the second cleaning unit in the one direction and that transmits a moving force for moving the first cleaning unit and the second cleaning unit to the first cleaning unit and the second cleaning unit.

An exposure device includes: a substrate that includes a plate-shaped main body that extends in one direction, a plurality of light emitting elements that are mounted on one surface of the main body, and a heating element that is mounted on the other surface of the main body and generates heat in accordance with light emission of the light emitting element; a housing that extends in the one direction, has a frame shape in which a through hole is formed, and to an inside of the through hole of which the substrate is fixed so that a thickness direction of the main body is a penetrating direction of the through hole; and a first contact member that extends in the one direction, and is in contact with at least a portion of the heating element and the main body at a different position in the one direction.

An exposure device includes: a substrate that includes a main body extending in one direction, light emitting elements on one surface of the main body, and a heating element on the other surface which generating heat upon emission of the light emitting elements; a housing having a frame shape which a through hole, to an inside of which the substrate is fixed so that a thickness direction of the main body is a penetrating direction of the through hole; a facing member fixed to the housing and opposing to the other surface; and a contact member contacting to the facing member and the heating element. An injection portion to inject a soft member as the contact member is formed between the substrate and the facing member on the facing member or the housing. When viewed a substrate side through the injection portion, the contact member covers partially the heating element.

An exposure device includes: a substrate that includes a plate-shaped main body that extends in one direction, a plurality of light emitting elements that are mounted on one surface of the main body, and a heating element that is mounted on the other surface of the main body generates heat in accordance with a light emitting operation of the light emitting elements; a housing that includes resin and that extends in the one direction, has a frame shape in which a through hole is formed, and to an inside of the through hole of which the substrate is fixed so that a thickness direction of the substrate is a penetrating direction of the through hole; and a suppression member that extends in the one direction, is fitted in the through hole, and suppresses thermal deformation of the housing.

An image forming apparatus includes a photosensitive member that is rotatable, a substrate, a lens array, a holder, and a conductive member provided on the holder. The substrate includes a plurality of light-emitting elements, a driver integrated circuit (IC), and a wiring pattern. The plurality of light-emitting elements is arrayed in a rotational axis direction of the photosensitive member to emit light to which a surface of the photosensitive member is exposed. The driver IC drives the plurality of light-emitting elements. The wiring pattern includes a supply line that supplies power to the driver IC and a ground wire that grounds the driver IC. The lens array collects the light emitted from the plurality of light-emitting elements on the photosensitive member. The holder holds the substrate and the lens array, is grounded, and is made of metal. The conductive member electrically connects the holder and the ground wire.

A light-emitting device includes: a first light-emitting unit that extends in one direction and that has a first emission surface that emits light located along the one direction; a second light-emitting unit that is located in the one direction with respect to the first light-emitting unit, that extends in the one direction, and that has a second emission surface that emits light located along the one direction; a cleaning unit that is capable of moving in the one direction and an opposite direction that is opposite to the one direction to clean the first emission surface; a transmission part that extends from the cleaning unit in the one direction and that transmits a moving force for moving the cleaning unit to the cleaning unit; and an extending part that extends from the transmission part in the one direction to elongate the transmission part. When the cleaning unit is positioned furthest in the opposite direction, an end of the extending part in the one direction is located further in the one direction than a midpoint between an end of the first light-emitting unit in the one direction and an end of the second light-emitting unit in the one direction.

According to an embodiment, a signal generation circuit includes a generation unit configured to generate a second clock signal from division of a first clock signal and generate a timing signal with a cycle length that is a sum of a predetermined number of half-cycle periods of the second clock signal. A period changing unit of the signal generation circuit is configured to adjust the cycle length of the timing signal by changing a length of at least one half-cycle period of the second clock signal. An output unit of the signal generation circuit is configured to output the second clock signal and the timing signal.

A light emitting device, includes: a base plate extending in a first direction; multiple light emitting units arranged on a surface of the base plate while being shifted from each other in the first direction, and each including a support body extending in the first direction and multiple light sources supported on the support body while being arranged in the first direction; and a flow path disposed over the surface of the base plate to surround at least part of the light emitting units and allowing air to flow therethrough in the first direction.