SCANNING LENS AND METHOD FOR MANUFACTURING SCANNING LENS

• US 20140160578A1
• Filed: 12/06/2013
• Published: 06/12/2014
• Est. Priority Date: 12/07/2012
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: JIBU, Yasuomi, WADA, Kazunobu
• Granted Patent: US 9,268,113 B2
• Time in Patent Office: Days
• US Class Current: 359/662
• CPC Class Codes: B29C 45/401 Ejector pin constructions or mountings
• CPC Class Codes: B29D 11/0048 Moulds for lenses moulds for plastic articles in general B29C33/00
• CPC Class Codes: B29L 2011/0016 Lenses
• CPC Class Codes: G02B 13/0005 having F-Theta characteristic scanning systems employing movable or deformable optical elements G02B26/10
• CPC Class Codes: G02B 26/125 Details of the optical system between the polygonal mirror and the image plane G02B26/123, G02B26/127 take precedence; F-Theta lenses G02B13/0005

Abstract

A scanning lens molded of resin includes: a lens portion having an elongate shape extending in a main scanning direction and having an optical surface; a slant portion having at least one slant surface slanting relative to the main scanning direction; and an ejector pin mark formed on the slant surface when thrusting out the scanning lens by ejector pins. The ejector pin mark is formed along a slanting direction of the slant surface.

Claims

1. A scanning lens molded of resin comprising:

a lens portion having an elongate shape extending in a main scanning direction and having an optical surface;

a slant portion having at least one slant surface slanting relative to the main scanning direction; and

an ejector pin mark formed on the slant surface when thrusting out the scanning lens by ejector pins,

wherein the ejector pin mark is formed along a slanting direction of the slant surface.

2. The scanning lens according to claim 1, wherein a parting line extending in the main scanning direction is provided on the scanning lens, wherein the slant portion has at least two slant surfaces which are spaced apart from each other in the main scanning direction, and each slant surface has an ejector pin mark, and wherein each slant surface and each ejector pin mark formed thereon is slanted in a direction away from the parting line toward inward of the scanning lens in the main scanning direction.

3. The scanning lens according to claim 2, wherein the slant surfaces and the ejector pin marks are provided symmetrically with respect to a center of the optical plane.

4. The scanning lens according to claim 1, wherein the slant portion is provided on each side in a sub-scanning direction of the lens portion, and wherein ejector pin marks formed on corresponding slant portions overlap each other as viewed from the sub-scanning direction.

5. The scanning lens according to claim 1, wherein the slant portion includes a pair of rib portions extending in the main scanning direction and provided on first and second sides of the lens portion which are located opposite to and away from each other in a sub-scanning direction, and wherein each of the pair of rib portions has at least one slant surface and an ejector pin mark formed thereon.

6. The scanning lens according to claim 1, wherein a surface of the ejector pin mark intersecting an optical axis direction is formed as a flat surface.

7. A method for manufacturing a scanning lens comprising a lens portion having an elongate shape extending in a main scanning direction and having an optical surface, and a slant portion having at least one slant surface slanting relative to the main scanning direction, the method comprising:

a first step of injecting resin into a mold having a mold area corresponding to a contour of the scanning lens; and

a second step of removing the scanning lens from the mold by moving ejector pins in an optical axis direction of the scanning lens,

wherein the ejector pins include at least one ejector pin having an end face shaped along a slanting direction of the slant surface, whereby the slant surface is pressed by the end face of the at least one ejector pin.

8. The method according to claim 7, wherein the at least one ejector pin is arranged at a position corresponding to each side in the main scanning direction of the lens portion, and the end face of the ejector pin is slanted in a direction away from a parting line of the scanning lens toward inward of the scanning lens in the main scanning direction.

9. The method according to claim 8, wherein the ejector pins are provided symmetrically with respect to a center of the optical plane.

10. The method according to claim 7, wherein the at least one ejector pin is provided at a position corresponding to each side in a sub-scanning direction of the lens portion, and wherein at least one ejector pin arranged at one side and at least one ejector pin arranged at another side overlap each other as viewed from the sub-scanning direction.

11. The method according to claim 7, wherein the end face of the at least one ejector pin is formed as a flat surface.