An image forming apparatus includes: a photoconductor that rotates about a first axis; an exposure portion that includes a substrate that includes a plurality of light emitting portions for exposing a surface of the photoconductor, and a support portion for supporting the substrate, and that moves between an exposure position where the photoconductor is exposed and a retracted position where the photoconductor is retracted from the exposure position; and a rotational member that has a second axis along the first axis, and that moves the exposure portion between the retracted position and the exposure position by rotation about the second axis.

A light emitting device configured to cause a series circuit in which an OLED is connected to a thin film transistor to emit light by applying a predetermined voltage to the thin film transistor includes: a forward direction voltage estimating unit configured to estimate a forward direction voltage in a case where the OLED is caused to emit light at a set light quantity; a driving current amount estimating unit configured to estimate a driving current amount required for causing the OLED to emit light at the set light quantity; a source-drain voltage calculating unit configured to calculate a source-drain voltage applied to the thin film transistor from the predetermined voltage and the forward direction voltage; and a gate-source voltage determining unit configured to determine a gate-source voltage of the thin film transistor corresponding to the source-drain voltage in a case where the driving current amount is a drain current.

An image forming apparatus includes a photosensitive member, light-emitting chips, and a controller integrated circuit (IC). Provided in each of the light-emitting chips are a plurality of light-emitting units that emit light for exposing the photosensitive member, a circuit unit that turns on and off the plurality of light-emitting units based on image data, and a storage unit that stores control data indicating a target amount of light of the plurality of light-emitting units. The light-emitting chips are arranged along a rotational axis direction of the photosensitive member. Each of the light-emitting chips is connected to the controller IC by a different one of a plurality of signal lines. In a case where the output control data is transmitted from the controller IC to each of the light-emitting chips via the different one of the plurality of signal lines, the transmitted control data is stored in the storage unit.

The image forming apparatus includes an exposure head. The exposure head includes an organic EL element array and a rod lens array, and forms an image on a photosensitive drum by irradiating light emitted from each organic EL element on the photoreceptor via each rod lens. In the exposure head, light emitting from the organic EL element is controlled by a controller. The controller generates a filter coefficient for correcting a spot shape based on the difference between the spot shape of the light spot on the photosensitive drum and the target spot shape on the photosensitive drum. It is noted that the difference is generated by the deviation between the distance from the organic EL element to the photosensitive drum, and the correct focus position.

An optical apparatus includes: a light source including multiple light-emitting points arrayed in a first direction; and an imaging optical system including multiple lens optical systems arrayed in the first direction. The imaging optical system forms images of the multiple light-emitting points on a light-receiving surface. In a first cross-section and in a second cross-section, half-value of a maximum value of angle of divergence of an imaging optical flux input to the light-receiving surface, resolution, and a size of each image of the plurality of light-emitting points formed on the light-receiving surface, satisfy predetermined conditions.

An exposure apparatus includes a chip with light-emitting elements arranged along an axial direction of a photosensitive member; a generation unit that generates a first synchronization signal synchronized with a second synchronization signal corresponding to a rotation speed of the photosensitive member; and a transmission unit that transmits a data signal to the chip during a line cycle. The second synchronization signal indicates a first or second cycle depending on the rotation speed. The second cycle is N times the first cycle. The first synchronization signal indicates the first cycle regardless of the rotation speed. When the photosensitive member rotates at a slower second rotation speed, the data signal of one line is transmitted to the chip during one of N line cycles; and a non-light-emission signal is transmitted during the remaining cycle(s) of the N line cycles.

An image forming apparatus includes: a photoconductor; a charging portion that charges a surface of the photoconductor; an exposure portion including a substrate including a plurality of light emitting portions for exposing the photoconductor; a developing portion that develops a latent image formed on the surface of the photoconductor with toner; a fan that generates an airflow for cooling the exposure portion; and a duct that communicates with the fan and communicates with the support portion, the duct guiding the airflow generated by the fan to the substrate; in which a part of the duct is formed by a charging support portion that supports the charging portion, a developing support portion that supports the development, and a duct portion, and a space between the duct portion and the charging support portion and a space between the duct portion and the developing support portion are sealed by a sealing member.

An image forming apparatus includes: a rotatable photoconductor; an exposure portion including a substrate on which a plurality of chips each including a plurality of light emitting portions that emit light for exposing the photoconductor is mounted, and a support portion configured to support the substrate; a fan configured to generate an airflow for cooling the exposure portion; and a duct configured to communicate with the fan and to communicate with the support portion to guide the airflow generated by the fan to the substrate.

An image forming apparatus includes an exposure light source including an organic light emitting element and a photoconductor configured to receive light emitted from the organic light emitting element, wherein a light emitting intensity of the organic light emitting element at end of supply of current to the organic light emitting element is defined as L.sub.0, a period from the end of supply of current to the organic light emitting element to quenching of the organic light emitting element is defined as T1, a period from start of supply of current to the organic light emitting element to the end of supply of current to the organic light emitting element is defined as T2, and T2 is larger than T1.

An exposure head includes: a light emitting chip including a plurality of light emitting portions arranged in a rotational axis direction of a photosensitive member and configured to emit light to expose the photosensitive member; a board on which the light emitting chip is mounted; a lens configured to condense the light emitted by the light emitting chip onto a surface of the photosensitive member; a housing configured to hold the board and the lens; a first adhesive configured to make the housing and the board adhere to each other, the first adhesive being cured at a first rate and having a cured elastic modulus of a first elastic modulus; and a second adhesive configured to make the housing and the board adhere to each other, the second adhesive being cured at a second rate and having a cured elastic modulus of a second elastic modulus, in which the second rate is higher than the first rate, and the first elastic modulus is higher than the second elastic modulus.