An exposure head that exposes a photosensitive member to light includes a plurality of light-emitting element array chips mounted on one surface of a board, a connector mounted on the other surface of the board, and a first driver IC and a second driver IC that are connected to the connector and drive the light-emitting element array chips, wherein the first driver IC is placed on one side of the board with respect to the connector in the longitudinal direction of the board, and the second driver IC is placed on the other side of the board with respect to the connector in the longitudinal direction of the board.

A printer includes at least a first printhead and a second printhead, each of which is operatively connected to a source of aqueous ink having a color that is different than the color of aqueous ink connected to the other printhead. A first source of infrared (IR) radiation is positioned between the first and second printheads and a second source of IR radiation follows the first and second printheads. The first source of IR radiation is tuned to heat color pigment particles in the aqueous ink connected to the first printhead only and the second source of IR radiation is tuned to heat color pigment particles in the aqueous ink connected to the second printhead only.

A printer includes at least a first printhead and a second printhead, each of which is operatively connected to a source of aqueous ink having a color that is different than the color of aqueous ink connected to the other printhead. A first source of infrared (IR) radiation is positioned between the first and second printheads and a second source of IR radiation follows the first and second printheads. The first source of IR radiation is tuned to heat color pigment particles in the aqueous ink connected to the first printhead only and the second source of IR radiation is tuned to heat color pigment particles in the aqueous ink connected to the second printhead only.

A liquid ejection device that ejects an ultraviolet-curable liquid includes an inkjet head, which is an ejection head that ejects the ultraviolet-curable liquid; a scanning driver that causes the inkjet head to perform a main scan; an ultraviolet generator; and a light source driver; where the ultraviolet generator irradiates the ultraviolet while moving in the main scanning direction together with the inkjet head; the ultraviolet generator includes a plurality of UV LED elements; the plurality of UV LED elements are arranged such that a light emitting range overlaps a range of the nozzle row in a sub scanning direction; and the light source driver drives the plurality of UV LED elements such that an illuminance at an end portion in the sub scanning direction is larger than an illuminance at a central portion in the light emitting range.

An image forming apparatus includes a print head, a detector, and a controller. The print head includes one or more light emitting element arrays, each light emitting element array includes a plurality of light emitting elements. The detector is configured to detect an emission time of the print head that emits light according to image data. The controller is configured to control a time interval to a print start corresponding to second image data, the second image data following first image data, based on a detection result of an emission time corresponding to the first image data.

An image forming apparatus includes a print head, a detector, and a controller. The print head includes one or more light emitting element arrays, each light emitting element array includes a plurality of light emitting elements. The detector is configured to detect an emission time of the print head that emits light according to image data. The controller is configured to control a time interval to a print start corresponding to second image data, the second image data following first image data, based on a detection result of an emission time corresponding to the first image data.

The present disclosure is drawn to printing systems. In one example, a printing system can include a first excimer irradiation source positioned to irradiate a media substrate. Additionally, an inkjet print head can be positioned with respect to the excimer irradiation source to form a printed image on the media substrate after irradiation with the excimer irradiation source.

An image forming apparatus includes a first light source, a second light source, an optical sensor, a storage, and a hardware processor, wherein the storage stores a first threshold for determining a type of the recording material based on the basis weight, and the hardware processor calculates a first transmittance from the mount of the first emission light and the amount of the first transmission light, calculates a second transmittance from the amount of the second emission light and the amount of the second transmission light, derives a first basis weight corresponding to the first transmittance and a second basis weight corresponding to the second transmittance, by using predetermined determination criteria, determines the type of the recording material based on the first basis weight and the second basis weight, and derives the basis weight according to the determination criteria based on the determined type of the recording material.

An image forming apparatus includes a first light source, a second light source, an optical sensor, a storage, and a hardware processor, wherein the storage stores a first threshold for determining a type of the recording material based on the basis weight, and the hardware processor calculates a first transmittance from the mount of the first emission light and the amount of the first transmission light, calculates a second transmittance from the amount of the second emission light and the amount of the second transmission light, derives a first basis weight corresponding to the first transmittance and a second basis weight corresponding to the second transmittance, by using predetermined determination criteria, determines the type of the recording material based on the first basis weight and the second basis weight, and derives the basis weight according to the determination criteria based on the determined type of the recording material.

An image forming apparatus includes an exposure head having an odd number of chips in each of which a plurality of light emitting elements configured to expose a photosensitive member are arrayed at intervals corresponding to a first resolution in an intersecting direction intersecting with a rotation direction of the photosensitive member. An even number of chips of the odd number of chips are arranged on one side of the printed circuit board in the rotation direction, and a remaining odd number of chips of the odd number of chips are arranged on another side of the printed circuit board. A center of an intensity of a light amount of the odd number of chips in the rotation direction is shifted to a side of the even number of chips with respect to a center of the printed circuit board in the rotation direction.