Light beam scanning device and image forming device

Abstract

The utility model relates to a light beam scanning device and an image forming device, and the light beam scanning device comprises a light source which is used for emitting a light beam; the light deflection device is used for deflecting the light beam emitted by the light source to the photoreceptor; the first optical mechanism is used for imaging the light beam deflected by the light deflection device onto a scanning surface of a photoreceptor, the first optical mechanism comprises at least one imaging lens, and the imaging lens is provided with an incident surface, a positioning surface and an emergent surface; the imaging lens is characterized in that the imaging lens meets the following condition that L1 / L2 is larger than or equal to 0 and smaller than or equal to 0.3, L1 is the distance between the vertex of the incident plane of the imaging lens and the positioning plane of the imaging lens, and L2 is the distance between the vertex of the incident plane of the imaging lens and the vertex of the emergent plane of the imaging lens. The imaging lens has the advantages that the influence of the assembling error of the imaging lens is reduced, the optical property is improved, and the processing and injection molding of the imaging lens are simpler.

Description

Technical Field

[0001] The utility model relates to the technical field of scanning, in particular to a light beam scanning device and an image forming device. Background Art

[0002] The light beam scanning device is used in an electrostatic copying type image forming device such as a laser printer, a digital copier, etc., in which an electrostatic latent image is formed by a laser beam, and a visible (developed) image is obtained by developing the electrostatic latent image.

[0003] There are many kinds of light beam scanning devices in the prior art, such as the Chinese invention patent "Light Beam Scanning Device" with patent number ZL03160256.8 (authorization announcement number CN100501496C), and the Chinese utility model "Optical Scanning Unit, Imaging Device and Printer for Printer" with patent number ZL202222293610.8 (authorization announcement number CN217932420U). Both of the above patents disclose light beam scanning devices. In the prior art, the light beam is deflected by an optical deflection device, and the deflected light beam is imaged onto the scanning surface of the photosensitive body through an imaging lens. However, the imaging lens in the prior art is relatively curved, and the processing difficulty will increase due to the high precision requirements during the processing; and when the imaging lens is injection molded, due to the high degree of curvature, the plastic solution is not fully glued, which may affect the optical properties.

[0004] Therefore, the prior art needs to be further improved. Utility Model Content

[0005] The first technical problem to be solved by the present invention is to provide a light beam scanning device which is easier to process and can obtain good optical characteristics in view of the above-mentioned prior art.

[0006] The second technical problem to be solved by the present invention is to provide an image forming device using the above-mentioned light beam scanning device in view of the above-mentioned prior art.

[0007] The technical solution adopted by the utility model to solve the first technical problem is: a light beam scanning device, comprising:

[0008] A light source for emitting a light beam;

[0009] A light deflecting device, used for deflecting the light beam emitted by the light source onto the photosensitive body;

[0010] A first optical mechanism, used to image the light beam deflected by the light deflection device onto a scanning surface of a photosensitive body, wherein the first optical mechanism comprises at least one imaging lens, and the imaging lens has an incident surface, a positioning surface, and an exit surface;

[0011] It is characterized in that: the imaging lens meets the following conditions:

[0012] 0≤L1 / L2≤0.3

[0013] Among them, L1 is the distance between the vertex of the incident surface of the imaging lens and the positioning surface of the imaging lens, and L2 is the distance between the vertex of the incident surface of the imaging lens and the vertex of the exit surface of the imaging lens.

[0014] Preferably, both the incident surface and the exit surface of the imaging lens are convex surfaces.

[0015] In order to enable the light beam to be incident on the light deflection device, preferably, a second optical mechanism is further included, wherein the second optical mechanism includes at least one lens arranged between the light source and the light deflection device, and the lens is used to enable the light beam emitted by the light source to be incident on the light deflection device.

[0016] Preferably, the light beam scanning device further comprises a feedback mirror arranged facing the light deflecting device, and the feedback mirror can emit a feedback light beam to the light deflecting device.

[0017] In order to achieve light deflection, preferably, the light deflection device is a polygonal reflector.

[0018] The technical solution adopted by the utility model to solve the above second technical problem is: an image forming device, comprising:

[0019] A beam scanning device;

[0020] a photosensitive body, used for forming an image from the light beam scanned by the light beam scanning device;

[0021] A developing device for developing the image formed on the photosensitive body;

[0022] It is characterized in that: the light beam scanning device uses the above-mentioned light beam scanning device.

[0023] Compared with the prior art, the advantage of the present invention is that by setting the imaging lens to satisfy the condition: 0≤L1 / L2≤0.3, L1 is the distance between the vertex of the incident surface of the imaging lens and the positioning surface of the imaging lens, and L2 is the distance between the vertex of the incident surface of the imaging lens and the vertex of the exit surface of the imaging lens, the distance between the positioning surface of the imaging lens housing and the maximum cross-sectional thickness portion of the imaging lens is reduced, thereby reducing the influence of the assembly error of the imaging lens. Therefore, even if the main scanning axis of the light beam scanning device rotates, the change of the imaging lens surface can be suppressed to a very small amount, so as to improve the optical properties and make the imaging lens processing and injection molding simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1A schematic diagram of a light beam scanning device in an embodiment of the utility model;

[0025] Figure 2 for Figure 1 Schematic diagram of the structure of the imaging lens;

[0026] Figure 3 for Figure 2 Another perspective structural diagram of;

[0027] Figure 4 for Figure 2 A front view of

[0028] Figure 5 The results of the experiment using an imaging lens with L1 / L2>0.3 are shown in the figure;

[0029] Figure 6 This is a result diagram of an experiment using the imaging lens in the embodiment of the utility model; DETAILED DESCRIPTION

[0030] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0031] like Figure 1 As shown, the light beam scanning device in this embodiment includes a light source 1, a light deflection device 2, a first optical mechanism and a second optical mechanism.

[0032] The light source 1 is used to emit a light beam; the light deflection device 2 is used to deflect the light beam emitted by the light source 1 onto the photosensitive body 3; in this embodiment, the light deflection device 2 is a polygonal reflector, and the first optical mechanism is used to image the light beam deflected by the light deflection device 2 onto the scanning surface of the photosensitive body 3, and the first optical mechanism includes at least one imaging lens 4, and the imaging lens 4 has an incident surface 41, a positioning surface 42 and an exit surface 43; the second optical mechanism includes at least one lens 5 arranged between the light source 1 and the light deflection device 2, and the lens 5 is used to make the light beam emitted by the light source 1 incident on the light deflection device 2.

[0033] like Figures 2 to 4 As shown, in this embodiment, the incident surface 41 and the exit surface 43 of the imaging lens 4 are both convex surfaces, and the imaging lens 4 meets the following conditions:

[0034] 0≤L1 / L2≤0.3;

[0035] Wherein, L1 is the distance between the vertex of the incident surface 41 of the imaging lens 4 and the positioning surface 42 of the imaging lens 4 , and L2 is the distance between the vertex of the incident surface 41 of the imaging lens 4 and the vertex of the exit surface 43 of the imaging lens 4 .

[0036] In addition, the light beam scanning device further comprises a feedback mirror 6 arranged facing the light deflecting device 2 , and the feedback mirror 6 can emit a feedback light beam to the light deflecting device 2 .

[0037] The utility model also relates to an image forming device, which includes the above-mentioned light beam scanning device, a photosensitive body 3 for forming an image with the light beam scanned by the light beam scanning device, and a developing device for developing the image formed on the photosensitive body 3. The image forming device can be used in a printer, that is, the above-mentioned photosensitive body 3 is a photosensitive drum.

[0038] In a light beam scanning device, the first direction of light beam scanning is usually referred to as the main scanning direction. The second direction perpendicular to the first direction is usually referred to as the sub-scanning direction. In an image forming device, the sub-scanning direction corresponds to the conveying direction of the transfer material, and the main scanning direction corresponds to the direction perpendicular to the conveying direction in the plane of the transfer material. In the image forming device, the image surface corresponds to the transfer material surface, and the imaging surface corresponds to the surface where the light beam is actually imaged. The positioning surface of the above-mentioned imaging lens is located near the main scanning direction line, and the main scanning direction line passes through the midpoint of the maximum cross-sectional thickness of the imaging lens.

[0039] In order to verify the effect of the imaging lens in the utility model, two different experimental results are compared in this embodiment with L1 / L2>0.3 and 0≤L1 / L2≤0.3. The results obtained when L1 / L2>0.3 are as follows: Figure 5 As shown, the linearity is the difference ratio between the actual image height and the theoretical image height when the light deflection device deflects the light beam to the imaging lens. The linearity reaches (+0.5% / -0.2%), and the upper deviation reaches +0.5%, which deviates from the median. When 0≤L1 / L2≤0.3, the result is as follows Figure 6 As shown, the linearity error is about ±0.3%, which can improve the linearity non-centering situation and make the optical properties good.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A light beam scanning device, comprising: A light source (1) for emitting a light beam; A light deflecting device (2) for deflecting a light beam emitted by a light source (1) onto a photosensitive body (3); A first optical mechanism, used for imaging the light beam deflected by the light deflection device (2) onto a scanning surface of a photosensitive body (3), the first optical mechanism comprising at least one imaging lens (4), the imaging lens (4) having an incident surface (41), a positioning surface (42) and an exit surface (43); The feature is that the imaging lens (4) satisfies the following conditions: 0≤L1 / L2≤0.3 Wherein, L1 is the distance between the vertex of the incident surface (41) of the imaging lens (4) and the positioning surface (42) of the imaging lens (4), and L2 is the distance between the vertex of the incident surface (41) of the imaging lens (4) and the vertex of the exit surface (43) of the imaging lens (4).

2. The light beam scanning device according to claim 1, characterized in that: The incident surface (41) and the exit surface (43) of the imaging lens (4) are both convex surfaces.

3. The light beam scanning device according to claim 1, characterized in that: It also includes a second optical mechanism, which includes at least one lens (5) arranged between the light source (1) and the light deflection device (2), and the lens (5) is used to make the light beam emitted by the light source (1) incident on the light deflection device (2).

4. The light beam scanning device according to claim 3, characterized in that: The light beam scanning device further comprises a feedback mirror (6) arranged facing the light deflection device (2), and the feedback mirror (6) can emit a feedback light beam to the light deflection device (2).

5. The light beam scanning device according to claim 4, characterized in that: The light deflection device (2) is a polygonal reflector.

6. An image forming device comprising: A beam scanning device; A photosensitive body (3) used for forming an image from the light beam scanned by the light beam scanning device; A developing device, used for developing the image formed on the photosensitive body (3); It is characterized in that the light beam scanning device uses the light beam scanning device described in any one of claims 1 to 5.

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