JPH026918A - Lens holding structure for scanning optical device - Google Patents

Abstract

PURPOSE:To hold a lens without exerting any adverse influence while holding position accuracy by fixing the lens to a holder detachable from a housing and positioning the lens by making the lens abut on positioning reference members provided on the housing side. CONSTITUTION:While the plane parts 9a and 9b of the lens 9 are allowed to about on the positioning members 8a and 8b, the positioning reference seat 10f of the lens holder 10 is allowed to abut against a fitting height reference seat 8e provided on the housing 8. A lens holder 10' is incorporated from above as well as the lower-stage side holder 10. Then the two holders 10 and 10' are fixed to the housing with screws 11g from above in the state wherein the plane parts of the lenses 9 and 9' held there are pressed against the reference members 8a and 8b at the same time. Thus, the front-rear and right-left directional positioning of the lenses to the housing is performed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a scanning optical device such as a laser beam printer, and particularly to a lens holding structure for holding and fixing a lens system.

(Prior Art) Conventionally, as this type of scanning optical device, there is one shown in FIG. 6, for example. Namely.

Reference numeral 1 denotes a semiconductor laser light source, which is fixed inside a housing (not shown). Inside the housing, a polygon mirror 3 is provided which is rotationally driven by a drive motor (not shown) in order to scan the beam emitted from the laser light source 1 in the axial direction of the photosensitive drum 2. Also,
Inside the housing, there is a collimator lens 4 that converts the laser beam into parallel light. A cylindrical lens 5 for condensing this parallel light onto the surface of the polygon mirror 3, a spherical lens 6 having fθ characteristics for condensing this condensed light beam conjugately on the photoreceptor drum z, and Aspherical Dolly lenses 7 are respectively arranged to constitute an imaging lens system.

The positioning and fixing of such an imaging lens system is performed, for example, as shown in FIG. That is, the lens 9 has plane parts 9a that are perpendicular to each other.

9b is formed, and these flat parts 9a, 9b are provided on the housing 8 with an abutment surface 8a for positioning and fixing.
, 8b to position it in the horizontal Y direction fF: U, After that, the not-illustrated recess provided in the housing 8 is the height reference seat [ζ plane part 9 (marked with :). Place it in the vertical direction and raise it to 1.

It was glued and fixed by 1° to an adhesive seat (not shown) that was 1° lower than this.

(Problem to be solved by the invention 11.) However,
For example, the fixing means for the imaging lens system as described above is
When applied to a scanning optical device using a plurality of di-beams, that is, when scanning optical devices are vertically stacked in two stages as shown in Fig. 6, consider the following example. When the imaging lens system is fixed to the housing by considering the extension of λ, as shown in FIG. The J&V structure is such that the lenses 9' are directly stacked and fixed in place with adhesive.

However, this method causes the following problems.

(1) As the number of multiplier lenses increases, extremely high precision pressure is required for the horizontality and f-plane degree of each cemented surface, resulting in an increase in cost.

(2) Also, 1 in the product direction.・Since the thickness of the lens increases and the height of the lens increases, the height of the lens increases by 1. It becomes easier to fall over, that is, it becomes difficult to maintain verticality.

(3) The lens group i- is attached to a height reference seat (not shown) provided in the housing 8;・Nzu 9,1
/ lenses 9', so if the machining accuracy of any one of the above parts is incorrect,
This would require replacing the entire thing, which would increase production costs. ＜ 、、、I have risen twice.

The present invention has been made to solve the problems described in -F, in a method for multiple loading and fixing of lens groups,
It is an object of the present invention to provide an inexpensive optical lens holding structure that can accurately maintain positional accuracy in the horizontal and vertical directions and does not adversely affect the optical path.

Another object of the present invention is to provide 1.1 in case a defective part occurs. −
It is an object of the present invention to provide a lens holding structure that allows only the relevant parts to be quickly replaced even in the event of a failure.

(Large Means for Solving the Problem) In order to achieve the above object, the present invention includes a light source that emits a plurality of beams and a plurality of lenses that converge each of the beams. Yes 12, use the lens as a vino,
In a scanning optical device which is stacked and arranged in a direction perpendicular to the scanning plane of the lens, each of the lenses is held by a holder that is detachable from the housing, and the lens is fixed to the housing via the holder. Common 1. :,
The lens is positioned by bringing the lens held by the holder into contact with a positioning reference member provided on the L housing side.

(Function) In the present invention, which corrects the above structure, there is no need to perform extremely high-precision processing on the lens and lens holder, and furthermore, defective parts can be easily replaced by simply removing the holder. It is.

(Example) The present invention will be explained below based on the illustrated example. In FIG. 5, the present invention is applied 1. In the same figure, 1 and 1' are l/-the light sources, which are vertically stacked in two stages.

The two I/-the beams A and A' emitted from these light sources are collimated by lenses 4 and 4', respectively.
The light passes through the cylindrical lenses 5 and 5', is reflected by the mirror surface of the polygon mirror 3 which is rotationally driven by a motor (not shown), becomes a scanning light, and is conjugated onto the photosensitive drum 2 via the imaging lens system R. The light is focused. Also scanned 1
A part of the /-zabino is captured by a not-shown optical sensor by a not-shown BD mirror to generate a horizontal synchronizing signal.

FIG. 1 shows a first embodiment in which the present invention is applied to an imaging lens system H, in which (a) is a perspective view and (b) is a front view. In the figure, 9 and 9' are planar arch-shaped plate lenses, and lens holders 10 and 10' on the upper and lower side, respectively.
are kept separately. To explain the lens holder by taking the lower lens holder 10 as an example, this holder lO is a plate-like member to which the lower surface of the lens 9 is fixed.

A positioning reference seat 10c is formed on the upper surface of the lens 9, with which the lower surface of the lens 9 comes into contact, and an adhesive dust 10d slightly lower than the positioning reference seat 10c is formed, and is formed by integral molding. Further, screw holes lo for fixing to the housing 8 are provided at both ends of the lens holder 10.
g is provided.

For mounting, height reference seats 10e and lOf are provided around the upper and lower openings of each screw hole 10g.

Furthermore, an escape hole 10a is provided at one end of the lens holder 1O, through which a reference member 8a protruding from the housing 8 passes.

On the other hand, the upper lens holder 10' has the same structure as the lower lens holder 1O, but in the case of the upper lens holder 10', the upper surface of the lens 9' is adhesively fixed to the lower surface of the upper lens holder 10'. The lenses 9 and 9' are mounted so as to face the lower lens holder 10.

Positioning reference seats 10c protruding from both ends of the upper and lower lens holders 10.10' abut against each other to determine the relative positional relationship between the two holders 10.10'.

On the other hand, the housing 8 has a columnar positioning reference member 8a for horizontally positioning the lenses 9 and 9'.
and 8b are provided to protrude vertically, and a height reference seat 8e is provided for mounting to vertically position the lens holder IO.

A specific procedure for fixing the lens holder and the lens held thereon to the housing is as follows.

First, to the positioning reference members 8a and 8b.

The positioning reference seat 10f of the lens holder 10 is attached to the height reference seat 8e provided in the housing 8 with the flat portions 9a and 9b of the lens 9 in contact with each other.

Next, a lens holder 10' is assembled from above in the same manner as the holder 10 on the lower stage side.

That is, to the positioning reference members 8a and 8b.

The flat parts 9'a and 9'b of the lens 9' are brought into contact with each other, and the positioning reference seat 10' of the lens holder 10' is moved.
When attaching the lens holder 10, the lens f is brought into contact with the height reference seat 10f.

Finally, the two holders 10°lO' are in a state in which the flat parts of the respective lenses 9 and 9' held therein are simultaneously pressed against the reference members 8a and 8b, that is, they are properly protruded. It is fixed to the housing 8 from above with the screw 11g while a force is applied so as to make it appear as follows.

Therefore, as described above, a plurality of lenses are positioned in the same row by the positioning reference members 8a and 8b.
It is possible to position a plurality of lenses with respect to the housing in the front, rear, left and right directions with high precision. Furthermore, the positioning reference seat surface of the lens holder and the mounting provided on the housing are such that the height reference seat surface is formed parallel to the laser beam scanning surface, that is, perpendicular to the laser beam scanning surface. Since it is coaxially fixed to the housing with two screws, it can be assembled and disassembled very easily.

(Other Embodiments) FIG. 2 shows a second embodiment of the present invention, and FIG.
is a perspective view, and (b) is a front view. The same members as those in the first embodiment are designated by the same reference numerals and repeated explanations will be omitted, and parts with different configurations will be explained.

The difference from the first embodiment is that the lens holder to, io'
For fixing the lens to the housing 8, height reference seats 8f and 8'f are provided for each lens holder. That is, the lens holders 10 and 10' have no portions that attach vE to each other.

In this case, when mounting the housing, it is necessary to provide as many height reference seats as there are lens holders. However, by doing this, when the lenses overlap in many stages, it is possible to reduce the dimensional error in the distance between the height reference planes of the laser beam scanning height position of each stage and the mounting of the housing. In the i-th embodiment, the 1/ns had a two-stage configuration, so
The above points can be ignored, but since there are many 1/ lenses, the 1/ lens holders are close to each other by R12, so the dimensional tolerances accumulate and the 6 housing The mounting method is similar to the second embodiment in that the dimension of the positioning reference seat of the lowest lens holder is removed from the height reference plane (4).

By taking this, you can reduce the V dimensional error.

Figure 3 shows @33 actual results of the present invention, and Figure (a)
The perspective view 2(b) is a front view. The same members as those in the second practical example are given the same reference numerals, and repeated explanations are omitted.
The different configuration parts will be explained.

The 8 parts that differ greatly from the first embodiment are the engagement holes 1()e and 1, O' at both ends of each lens holder.
e, and these engagement holes 10e, j,
Due to the engagement between O'e and the engagement pins 8e and 8'e protruding from the housing 8, the nozzling 8 is forced to
- The above-mentioned retaining hole 1Oe is used for downward positioning.

10'e is an oblong hole to accommodate dimensional errors in the 1/lens holder, etc.

1. Therefore, in this embodiment 'c', the lens is
It becomes possible to perform positioning (l-bottom, front and back, left and right) with high precision. Furthermore, in the first and second embodiments, if the lowest lens is found to be defective, there is the inconvenience that the F-most lens holder cannot be replaced unless all lens holders are removed. However, in the first aspect of the present invention, the lens holders can be attached to the housing without drying out from each other, so handling is convenient.

FIG. 4 shows a fourth embodiment of the present invention.
) is a perspective view, and (b) is a front view. The same members as those in the third embodiment are designated by the same reference numerals, and repeated explanations will be omitted, and parts with different configurations will be explained.

The major difference between the third embodiment and the third embodiment is that the Howe lens 12 to which the lens holder is attached is housed in the removable housing of the scanning optical device. The housing 12 is positioned in the horizontal direction by engagement between a retaining pin 8h protruding from the mA8 and an engagement hole (not shown) provided in the housing 12. The vertical positioning is performed with crystal precision by bringing the height reference socket i into contact with the 12 prongs outside the positioning reference of the housing 1z.

For example, the third embodiment can be used to create multiple lens cannons that can be stacked as is. As the TT increases, the length of the positioning reference member provided in the housing becomes longer, making it difficult to mold the body. In addition, dimensional accuracy and ease of assembly will deteriorate.1.1. Therefore, by making the housing to which the lens holder is attached a separate member as in this embodiment, this problem can be solved and the ease of assembly and disassembly can be improved.

In the above embodiment, the 1/lens holder and the lens were constructed as separate members, but a molded structure by integral molding may also be used.

Furthermore, one example in which the present invention is applied to a g-image lens has been described. collimator lens, cylindrical lens,
Of course, it can also be used in optical systems such as reflective mirrors.

(Effects of the invention:!!) The present invention consists of the following structure and operation:
The l/ns held in the housing 1
．． , each time it comes into contact with a generally angular positioning reference member, it is possible to install a 1/2 lens without reducing the accuracy of the positioning without increasing the production cost. It is possible to maintain accurate position. At 4,
In the event that a defect occurs in the lens, it is possible to easily replace only the affected part with a normal one.

[Brief explanation of the drawing]

Figure m1 shows an embodiment according to the present invention.
(a) is a perspective view, (h) is a front view, (C) is a plan view with the lower lens holder visible, and FIGS. 2 to 4 each show other embodiments of the present invention. 1 and 4 (each figure (a) is a perspective view, (b) is a hemostasis diagram,
FIG. 5 is a perspective view of a scanning optical device according to the present invention (!), FIG. 6 is a perspective view of a conventional laser beam scanning device, FIG. 7 is a perspective view of a conventional lens holding structure, and FIG. is a reference diagram of a plurality of lens fixing and holding structures. Explanation of symbols 1...Laser light source 2...Photoconductor drum 3...
・Polygon mirror 6.7.9...Imaging lens 8...Housing 8a, 8b...Positioning reference member 8e...Mounting is done using height reference seats 9a, 9'a, 9b, 9'b-・-Plane part 10.10'
... Lens holder No. 7 N C Figure 8 Teitouri Uchu Masao) (Method) 6. Subject of correction (1) Column 7 of "Brief explanation of drawings" in the specification. Contents of correction (1) Details Immediately divide "reference" by j in the third line of page 15 of the book.

Claims (1)

[Claims] Scanning optics that includes a light source that emits a plurality of beams and a plurality of lenses that converge the beams, the lenses being stacked in a direction perpendicular to the scanning plane of the beams. In the apparatus, each of the lenses is held by a holder that is detachably attached to the housing, and the lens is fixed to the housing via the holder, and the lens is positioned on the holder using a positioning reference member provided on the housing side. A lens holding structure for a scanning optical device, characterized in that the lens holding structure is carried out by bringing a held lens into contact with each other.