# US 2014/0192384 A1 · Exposing device and image forming apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0192384 A1
- Document ID: US20140192384A1
- Status: Published application
- Kind: A1
- Application number: 14/146,289
- Filed: 2014-01-02
- Published: 2014-07-10
- Earliest claimed: 2013-01-09
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Aihiko Numata
- Web page: https://patentgrep.com/patent/US20140192384A1

## CPC

- G03G 15/043: with means for controlling illumination or exposure (G03G15/041 takes precedence)
- G03G 15/0435: {by introducing an optical element in the optical path, e.g. a filter}
- G03G 15/04072: {by laser}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

Provided is an exposing device capable of enhancing usage efficiency of light and preventing degradation of imaging property due to a misalignment with a photosensitive drum. The exposing device includes: a laser array including multiple lasers arranged in a predetermined direction; and an optical system guiding light emitted from the each of the multiple lasers to a photosensitive member and focusing the light on the photosensitive member, in which the optical system includes multiple phase modulation elements to decrease a phase lag added in proportion to distance from a center axis that is defined by a principal light beam emitted from the each of the multiple lasers.

## Claims

### Claim 1

An exposing device, comprising:
a laser array including multiple lasers arranged in a predetermined direction; and
an optical system guiding light emitted from the each of the multiple lasers to a photosensitive member and focusing the light on the photosensitive member,
wherein the optical system includes multiple phase modulation elements to decrease a phase lag added in proportion to distance from a center axis that is defined by a principal light beam emitted from the each of the multiple lasers.

### Claim 2 (depends on 1)

The exposing device according to claim 1, wherein the multiple lasers are arranged in a longitudinal direction of the photosensitive member at regular intervals.

### Claim 3 (depends on 2)

The exposing device according to claim 2, wherein:
the multiple lasers are further arranged in a lateral direction of the photosensitive member at predetermined intervals;
an interval between two adjacent lasers in the lateral direction is larger than an interval between the two adjacent lasers in the longitudinal direction; and
a radius of the phase modulation element is larger than the interval between two adjacent lasers in the longitudinal direction.

### Claim 4 (depends on 1)

The exposing device according to claim 1, wherein:
the multiple lasers are arranged in a two-dimensional array; and
a number of the multiple lasers arranged in a lateral direction of the photosensitive member is equal to or larger than a value obtained by dividing an interval between two adjacent lasers in the lateral direction by an interval between two adjacent lasers in a longitudinal direction of the photosensitive member.

### Claim 5 (depends on 3)

The exposing device according to claim 3, wherein the multiple lasers comprise lasers facing a periphery of the photosensitive member in the lateral direction at a smaller interval in the lateral direction.

### Claim 6 (depends on 1)

The exposing device according to claim 1, wherein the phase modulation element comprises an axicon lens.

### Claim 7 (depends on 1)

The exposing device according to claim 1, wherein the phase modulation element comprises a gradient index lens.

### Claim 8 (depends on 1)

The exposing device according to claim 1, wherein the laser comprises surface-emitting laser.

### Claim 9 (depends on 8)

The exposing device according to claim 8, wherein the surface-emitting laser comprises a light source to emit a radially polarized beam.

### Claim 10 (depends on 9)

The exposing device according to claim 9, wherein the surface-emitting laser comprises a distributed feedback surface-emitting laser including an active layer and a two-dimensional photonic crystal.

### Claim 11 (depends on 10)

The exposing device according to claim 10, wherein:
the two-dimensional photonic crystal comprises a square lattice; and
a shape of a lattice point thereof has a four-fold rotational symmetry.

### Claim 12 (depends on 10)

The exposing device according to claim 10, wherein each of the multiple phase modulation elements corresponds to different one of the multiple lasers.

### Claim 13 (depends on 1)

An image forming apparatus, comprising:
the exposing device according to claim 1; and
a photosensitive member.