An exposure unit includes a light-emitting element array and a lens array. The light-emitting element array includes a plurality of light-emitting elements that are disposed in a first direction and each emit a light beam. The lens array faces the light-emitting element array in a second direction that is orthogonal to the first direction, and focuses the light beams emitted from the respective light-emitting elements. The following expression [3] is satisfied. A symmetric property, determined from the following expression [1], of a light amount distribution in the first direction of at least one of the light beams focused by the lens array satisfies the following expression [2].

S=|(HLHR)/(XE/2)|[1]

0S0.65[2]

LoLB[3]

Provided is an exposure unit that performs exposure of an image supporting member and includes a light-emitting element array, and a lens array. The light-emitting element array includes light-emitting elements that are disposed in a first direction and each emit a light beam. The lens array faces the light-emitting element array in a second direction that is orthogonal to the first direction, and focuses the light beams. The following expressions (1) and (2) are satisfied.

175 mL0L1250 m(1)

175 mL0L2250 m(2)

where L0 is a focal distance of the lens array in which a contrast, determined from a light amount distribution in the first direction of any of the light beams focused by the lens array, becomes maximum, and L2 is a distance from the lens array to the image supporting member.

A lens, a light scanning unit, and an electrophotography type image forming apparatus includes effective optical surfaces, wherein reference indicating portions to measure a decenter of the lens are arranged on the effective optical surfaces.

An LED light-emitting module is provided, including a glass substrate, a drive circuit, an LED light-emitting assembly, and a drive chip. The drive circuit is disposed on a side surface of the glass substrate. The LED light-emitting assembly includes a plurality of LED light sources arranged in an array manner. The LED light-emitting assembly is disposed on a surface of the drive circuit and is electrically connected to the drive circuit. The drive chip is connected to the drive circuit, and controls, by using the drive circuit, the LED light source in the LED light-emitting assembly to be turned on or off.

There is provided a light scanning apparatus that is free from main scanning jitter and allows size reduction of a deflector. The light scanning apparatus has a plurality of light sources, a deflector that deflects a plurality of light fluxes emitted from a plurality of light sources to scan a plurality of scanned surfaces along a main scanning direction, and a first stop arranged between the plurality of light sources and the deflector and provided with an aperture that regulates the width of the plurality of light fluxes with respect to the main scanning direction. The number of apertures of the first stop is smaller than the number of light sources.

A single-pass imaging system utilizes a two-dimensional (2D) light field generator (e.g., one or more VCSEL devices) to generate a modulated two-dimensional modulated light field in accordance with image data for a single row of pixels, and an anamorphic optical system that concentrates the two-dimensional modulated light field in a process direction such that a one-dimensional scan line image extending in a cross-process direction is generated on an imaging surface. The VCSEL array is configured using a scan line image data group made up of pixel image data portions, with associated groups of light emitting elements aligned in the process direction being configured by each pixel image data portion. Gray scaling is achieved either by turning on some of the light emitting elements of the associated group, or by turning the light emitting elements of the associated group partially on, e.g. using a common drive current.

An imaging device for projecting individually controllable laser beams onto an imaging surface movable in an X-direction. The device includes a plurality of semiconductor chips each comprising a plurality of laser beam emitting elements arranged in a main array of M.Math.N. The chips are mounted such that each pair of adjacent chips in the Y-direction are offset from one another in the X-direction and, if activated continuously, the emitted laser beams of the two chips of said pair trace on the imaging surface a set of parallel lines that are substantially uniformly spaced in the Y-direction. In addition to the M.Math.N elements of the main array, each chip comprises at least one additional column on one or each side, each additional column containing at least one selectively operable element capable of compensating for any misalignment in the Y-direction in the relative positioning of the adjacent chips on the support.

An imaging device is disclosed for projecting individually controllable laser beams onto an imaging surface that is movable relative thereto in X-direction. The device includes a plurality of semiconductor chips comprising a plurality of individually controllable laser emitting elements arranged in a two dimensional array of M rows and N columns. The chips are mounted on a support in at least one pair of rows, such that each pair of adjacent chips in Y-direction are offset from one another in the X-direction, and the laser beams are substantially uniformly spaced in the Y-direction. The chips are arranged such that corresponding elements in any group of three adjacent chips in the X and Y-directions lie at the apices of congruent equilateral triangles. A plurality of GRIN rod based lens systems focuses the beams for each of the chips onto the imaging surface.

The invention relates to a laser based printing apparatus (100) using laser light sources (111, 112, 113, 402, 404, 406, 604, 606, 808, 810) for supplying energy to a target object (120) to form an image. The printing apparatus (100) comprises a laser light source arrangement (110, 400, 600) comprising a plurality of laser light sources (111, 112, 113, 402, 404, 406, 604, 606, 808, 810) arranged such that laser beams (114, 410, 805, 806) of the laser light sources (111, 112, 113, 402, 404, 406, 604, 606, 808, 810) intersect a surface (121) of a target object (120) at different target points (123, 24, 125, 412, 414, 416, 616, 610, 802) along a moving direction (122), a transport mechanism (130) for moving the target object (120) and the laser light sources (111, 12, 113, 402, 404, 406, 604, 606, 808, 810) relatively to each other in the moving 10 direction (122) and a controlling arrangement (140), which is realized to control the laser light sources (111, 112, 113, 402, 404, 406, 604, 606, 808, 810) and/or the transport mechanism (130) based on image data (150) in such a way, that the energy level of a target point (123, 124, 125, 412, 414, 416, 616, 610, 802) is stepwise increased by irradiation of at least two different laser light sources along the moving direction (122). The invention also describes a method for controlling such a laser based printing apparatus (100).

An imaging device includes: M rotatable photosensitive drums, at least one display chip, at least one projection lens, and at least one beam deflection system. The light-receiving region of each photosensitive drum includes multiple light-receiving sub-regions. Each display chip includes at least two light-emitting regions arranged in a first direction. At least one projection lens is in one-to-one correspondence with the at least one display chip. Each projection lens is configured to form an image for a corresponding display chip. The at least one beam deflection system is in one-to-one correspondence with the at least one display chip. The beam deflection system is configured to deflect an image, which is formed by light from each light-emitting region in the display chip through a corresponding projection lens, to a corresponding light-receiving sub-region.