JP3201151B2 - Optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device, and more particularly, to a mirror mounting structure for changing a path of a light beam in an optical device.

[0002]

2. Description of the Related Art Conventionally, a scanning optical apparatus applied to an electrophotographic image forming apparatus such as a laser printer, a copying machine, a facsimile machine, etc., has an upper surface open as disclosed in Japanese Utility Model Laid-Open No. 2-64959. In a box-shaped housing case, a rotating polygon mirror having a hexagonal shape in plan view as a deflector rotated by a motor mounted on the bottom surface thereof and a lens group as a scanning optical system such as an fθ lens are fixedly provided. A laser unit including a semiconductor laser element as a light source and a collimating lens is mounted on one side wall surface of the housing case, and a light beam emitted from the laser unit is modulated according to image data to be a rotating polygon mirror. The light beam reflected here is changed its course by a mirror provided in the housing case via a lens group such as an fθ lens. It is known that light is condensed (imaged) on the surface of a rotating photosensitive drum through a window hole formed in one side of a housing case from the mirror.

[0003] In this case, the above publication discloses that the rear surface of a mirror, whose surface is in contact with a support reference surface provided on the inner surface of the housing case, is fixed to the inner surface of the housing case by a spring plate whose base is fastened with screws. Is disclosed.

[0004]

However, this spring plate has to be screwed to the housing case one by one, which requires a lot of time for the mounting operation, the mirror is shifted to the left and right, etc. There has been a problem that the mirror cannot be prevented from falling off from the supporting portion of the housing case. The present invention has been made in order to solve these technical problems, and an object of the present invention is to provide an optical device that can easily mount a mirror and can prevent the mirror from falling off or moving. Things.

[0005]

In order to achieve the above object, in the optical apparatus according to the first aspect of the present invention, a mirror for changing the course of a light beam is mounted on a housing case via a mounting member made of a spring plate. In the optical device to be mounted,
A board of a spring plate mounting bracket is configured to be inserted into a mounting hole formed in a housing case, and the substrate has a retaining locking claw for locking to a step formed in the mounting hole. while providing the front Stories substrate a resilient locking piece provided with a position regulating portion for preventing the lateral displacement of the pressing portion and a mirror for pressing toward the mirror based support portion provided in the housing case from the back side Are provided integrally.

[0006] The optical device according to the second aspect is the first aspect.
In the invention of the above, the substrate of the mounting bracket made of spring plate,
To prevent the mirror from falling off the housing case.
And a drop-off prevention piece for providing the same.

According to a third aspect of the present invention, there is provided an optical device according to the first or second aspect.
And have our invention of claim 2, wherein in the vicinity of the mounting holes in the housing case, the guide piece for guiding and supporting the back of the substrate of Preparative securing fixture is obtained form standing 設形.

An optical device according to a fourth aspect is the optical device according to the third aspect.
In the invention, the guide piece is provided with the retaining locking claw.
And a guide groove for guiding the
You.

[0009]

Next, an embodiment of the present invention will be described. FIG. 1 is a schematic sectional side view of a laser beam printer 1 as an image forming apparatus, and FIG. 2 is a sectional side view of a scanning optical device.

In the printer 1 of this embodiment, a paper feed cassette 3 as a paper feed unit is detachably mounted on the upper side of one side of the main body case 2, and the paper feed roller 4 and the separation pad 5 are used to mount the paper feed cassette 3 inside the paper feed cassette 3. P as a recording medium laminated on a sheet
Are separated one by one and sent to the image forming unit 9 via the feed roller pair 6.

The image forming unit 9 includes a rotating photosensitive drum 7 as a photosensitive member and a transfer roller 8 as a transfer unit.
And a developing device unit 12 including a toner cartridge 10 and a developing roller 11 at a position close to the paper feed cassette 3 side, and a charging device 13 and a cleaning device 14 on the lower surface side of the photosensitive drum 7 as one kit in a case. To form a single unit.

On the discharge side of the image forming unit 9, a fixing device 17 including a heating roller 16 and a pressing roller 15 is disposed.

Below the image forming unit 9, a scanner unit 18 as a scanning optical device for scanning a laser beam toward the lower surface of the photosensitive drum 7 is provided with a top plate of a downwardly open housing case 30. It is detachably mounted on the upper surface of the flat plate portion 2b of the main frame 2a of the main body case 2 with the upper side 30a.

A laser beam emitted from a scanner unit 18 to be described later is applied to the surface of the photosensitive drum 7 charged in advance by the charging device 13 in accordance with image data transmitted from an external device such as a host computer (not shown). Irradiate light to form an electrostatic latent image on the surface of the photosensitive drum 7;
Then, after the developing roller 11 is rotated to supply a charged powdery toner to develop the latent image into a visible image, the transfer between the photosensitive drum 7 and the transfer roller 8 is performed. The toner image is transferred to the sheet P supplied to the portion, and then passes between the heating roller 16 and the pressing roller 15 in the fixing device 17 to apply heat and pressure to the transferred toner image. To fix the toner image on the paper P. After that, the paper discharge tray 63 is passed through the paper discharge roller pair 62.
Is to be discharged.

A control board 60 and a high-voltage board 61 for applying a high voltage to the charging device 13 and the transfer roller 8 are arranged below the main frame 2a. Next, the configuration of the scanner unit 18 will be described with reference to FIG.
This will be described with reference to FIGS. FIG. 3 is a cross-sectional view of FIG.
FIG. 2 is a bottom view of the inside of a housing case 30 made of glass-reinforced plastic mixed with short glass fibers, which is a downward open box shape, as viewed in the direction of the arrow I.

In the scanner unit 18, a laser light emitting unit 20, a rotating polygon mirror 27 as a deflector, f
The components including the θ lens 21, the cylindrical lens 22, the folding mirror 23, the writing signal (BD) mirror 25, the writing signal (BD) detection sensor 26, and the like are placed in a downwardly open box-shaped housing case 30. 30a
And is fixed to the inner surface (lower surface) of the.

A laser emitting unit 20 in which a semiconductor laser as a light source and a collimate lens (both not shown) are built in a block body 28 is disposed on one side far from the photosensitive drum 7 and is provided with the top plate 30a. Is screwed and fixed to the lower surface. On the back of the block 28, the printed wiring board 2
9 are attached.

A rotary polygonal mirror 27 such as a six-sided mirror, which is rotated in a substantially horizontal direction by a drive motor 31 fixed to the inner surface of the top plate 30a, enters the laser emitting unit 20 toward the mirror surface. The optical axis of the light beam is the photosensitive drum 7
Are arranged so as to be substantially parallel to the rotation axis. The light beams reflected by the mirror surface of the rotary polygon mirror 27 are attached at both ends to mounting brackets 32a, 32b, 33 made of leaf springs.
a, 33b, through an fθ lens 21 and a cylindrical lens 22 fixed to a mounting slit hole (not shown) of the top plate 30a, and by a folding mirror 23, the photosensitive drum 7
Is reflected in the lower surface direction. A long window hole 34 is formed in the top plate 30a of the housing case 30 near the lower surface of the photosensitive drum 7 in a direction parallel to the axis of the photosensitive drum 7, and the cover for covering the window hole 34 is provided. Through the plate 24, the deflected light beam scans the lower surface of the photosensitive drum 7 along the axial direction of the photosensitive drum 7.

The distance between the optical axis of the lens 21 and the imaging spot on the surface of the photosensitive drum 7 is determined by the fθ lens 21 and the principal ray reflected by the reflecting surface of the rotary polygon mirror 27 which is a deflector. Deflection angle θ with the optical axis of fθ lens 21
Has the property of being proportional to

A BD (Beam Detector) mirror 25, which is also fixed by a leaf spring (not shown), is disposed near one end in the longitudinal direction of a folding mirror 23 to be described later. A write start position signal (BD signal) for detecting a write start position in the horizontal direction of the photosensitive drum 7 in the light beam emitted from the unit 20 is
The light is input to the BD detection sensor 26 through the path of the rotary polygon mirror 27, the fθ lens 21, the cylindrical lens 22, the BD mirror 25, the slit body 35, and the condenser lens 36. A laser driving board (printed wiring board) 37 for processing the signal input to the BD detection sensor 26 and driving the laser light emitting unit 20 contacts an end surface of a rib protruding downward from the inner surface of the top plate 30a. They are brought into contact with each other and fixed with screws 38.

A window hole 34 through which a light beam radiated toward the photosensitive drum 7 through the lens group and the folding mirror 23 passes is provided at a front side of the top plate 30a of the housing case 30 (in the photosensitive drum 7). In the inclined portion 50 on the (closer side), it is formed in the left and right longitudinal direction along the axis of the photosensitive drum 7 so as not to protrude outside the peripheral side wall 30b of the housing case 30.

From the left and right longitudinal ribs 51 projecting upward from the inclined portion 50, a pair of left and right engaging claw blocks 52, 52 are formed so that their engaging surfaces (lower surfaces) are approximately 60 degrees with respect to the surface of the inclined portion 50. A glass plate or a glass plate attached to the surface of the inclined portion 50 at the locking surface of each locking claw block 52 at an acute angle of an angle θ1 such as a degree (see FIG. 5). , An outer corner portion (an inclined portion 5) at one longitudinal side edge of the light-transmitting cover plate 24 made of a material such as a transparent synthetic resin plate.
0 (the corner on the side away from the surface of 0). Also, at the positions facing each other (the opposite faces) with the left and right locking claw blocks 52, 52, the base ends 53a of the substantially U-shaped elastic locking pieces 53, 53 in side view are provided on the outer surface of the peripheral side wall 30b. The fixed side is provided (see FIGS. 3 and 5). At this time, the outer surface of the elastic locking piece 53 on the free end 53b side is elastically bent toward the surface of the inclined portion 50 at the outer corner at the other longitudinal edge parallel to the longitudinal one edge of the cover plate 24. The free end 53b is formed so as to extend at an acute angle of an angle θ2 such as approximately 60 degrees with respect to the surface of the inclined portion 50 so as to be pressed.

Next, the mounting structure of the folding mirror 23 to the housing case 30 will be described with reference to FIGS. The folding mirror 23 is elongated parallel to the longitudinal direction of the cover plate 24 and the cylindrical lens 22 and has a substantially rectangular cross section. As shown in FIGS. 4 and 5, a top plate 30a of the housing case 30 is provided.
First reference support portions 5 integrally formed on the left and right sides of the inner surface
4, the surface side (reflection surface side) of the folding mirror 23 is supported,
The end face of the thickness of the folding mirror 23 is supported by the second reference support portion 55, and as shown in FIG.
Are inclined with respect to the surface of the top plate 30a so that the light beam emitted from the top plate goes to the cover plate 24.

A pair of right and left spring plate mounting brackets 56 for supporting the left and right sides of the folding mirror 23 are shown in FIGS.
As shown in FIG. 6, a vertical board 57, an elastic locking piece 58 formed by bending from the board 57, and a falling-off prevention piece 59 are provided. As shown in FIG. Each of the mounting brackets 56 has an elastic locking piece 58 and a falling-off prevention piece 59 formed symmetrically with respect to the substrate 57. In the middle of each of the substrates 57, a retaining locking claw 57a which can be locked in a stepped portion 65a formed in a mounting hole 65 to be described later is cut and raised.

Each elastic locking piece 58 has a protruding pressing portion 58a for pressing the back surface of the folding mirror 23 against the first reference supporting portion 54 and the second reference supporting portion 55, and a longitudinal portion of the folding mirror 23. It is integrally provided with a position restricting portion 58b for preventing lateral displacement that comes into contact with the end surface in the direction.

Further, each of the falling-off preventing pieces 59 is
7 is formed so as to be bent by approximately 90 degrees from the side surface, and the housing case 30 is mounted on the main body frame 2a so that the top plate 30a thereof is positioned above (the state in which FIG. 5 is upside down).
In order to prevent the folding mirror 23 from falling off in the direction away from the top plate 30a even when a downward impact force acts, the side view L
A holding portion 59a having a letter-shaped notch is formed.

The lower end of the substrate 57 is formed with a chamfered portion 57b so as to be shorter on the side of the drop-off preventing piece 59, and a knob 57c is formed at the upper end of the substrate 57 by bending.

On the other hand, the top plate 30a of the housing case 30
A pair of left and right mounting holes 65 in the form of a horizontal slit
, Guide pieces 66 for guiding and supporting the back surface of the substrate 57 of the mounting bracket 56 are provided on the opposite sides of the first reference support portions 54, respectively. A vertically long guide groove 66a for guiding the locking claw 57a to the step portion 65a is formed.

With this configuration, when mounting the long folding mirror 23 on the left and right with the housing case 30 arranged with the top plate 30a facing down, first,
The reflecting surface of the turning mirror 23 is in contact with the reference support portion 54, and the mirror is placed on the second reference supporting portion 55 such that the end surface on the thickness side of the turning mirror 23 is in contact with the second reference support portion 55. Then, the knob 57c is pinched by a finger. The retaining claw 57a is fitted in the guide groove 66a, and the mounting hole 6 is kept in an oblique posture with the long foot side of the substrate 57 first.
Insert into 5.

Next, the knob 57c is pinched by a finger so that the position restricting portion 58b of the elastic locking piece 58 comes into contact with the longitudinal end face of the folding mirror 23, and is pushed into the mounting hole 65 while changing the posture of the substrate 57. And the retaining locking claw 57
a is locked to the stepped portion 65a and cannot be removed, and the pressing portion 58a of the elastic locking piece 58 elastically presses the back surface of the folding mirror 23, and the folding mirror 23 is moved to the first reference support portion 54. And the second reference support portion 55 can be closely contacted without play.

In this way, when the folding mirror 23 is mounted on the housing case 30 via the mounting bracket 56, it is possible to eliminate the troublesome work of screwing and the like and to mount the folding mirror 23 with one touch. And
To assemble the scanner unit 18 as the scanning optical device with the printer 1, a pair of front and rear tie bars 40 and 41 are previously attached to the upper surface (outer surface) of the top plate 30 a of the housing case 30 with screws 42, 43, 44 and 45. The housing case 30 is turned upside down and the top plate 3
0a is arranged so that the inner surface thereof faces upward (see FIG. 3), and the above components and the printed wiring board 37 are disposed on the inner surface of the top plate 30a.
Is fixed.

Next, the pair of tie bars 40 and 41 are set on a predetermined jig for performance inspection, the intensity of the light beam emitted from the laser emitting unit 20 is set, and then the fθ lens 21 and the cylindrical The fixing posture of the lens 22 or the like is inspected, and the position of the slit body 35 is adjusted so that the BD signal is received by the BD detection sensor 26, and then the slit body 35 is fixed with an adhesive.

Thereafter, a sealing material 46 such as a sponge material made of a synthetic resin is placed over the free edge of the peripheral side wall 30b of the housing case 30.
0 is turned downward (top plate 30a is turned up) (see FIGS. 4 and 5), and placed on the upper surface of the flat plate portion 2b of the main frame 2a in the main body case 2 made of synthetic resin. , 41 are fixed to predetermined positions such as the stepped portion 2c of the main frame 2a with screws 47, 48.

With this configuration, the optical systems such as the laser light emitting unit 20, the rotary polygon mirror 27, and the fθ lens 21, which are the components of the scanning optical device, are all mounted on the box-type housing case 30 with the bottom open. The window hole 34 that is covered with the light beam and passes through the locking claw block 52 and the substrate 57
And the elastic locking piece 53, is covered with the cover plate 24 which is brought into close contact with the surface of the inclined portion 50.
Since the seal member 46 is interposed and fixed between the upper surface of the flat plate portion 2b and the upper surface of the flat case portion 2a, it is possible to save the trouble of mounting a separate lid on the upper surface of the conventional upwardly open box-shaped housing case. Housing case 3
The toner leaking from above the housing case 30
Of the scanning optical device in the housing case 30 can be completely prevented.

Incidentally, the optical components such as the semiconductor laser, the respective lenses, and the mirrors may be displaced with the passage of time, which may hinder the operation as the scanning optical device. In such a case, it is possible to replace only the defective optical component. However, since the mounting accuracy of the optical component is required at the time of replacement, the entire unit of the scanning optical device is usually replaced. At this time, the top plate 3 of the housing case 30 is
If a plurality of tie bars 40, 41 are mounted on the upper surface of the main frame 2a,
The housing case 30 can be mounted simply by fixing it with a small number of screws at appropriate locations, and the mounting operation can be simplified.

As another embodiment, the housing case 30
Needless to say, the laser light emitting unit 20 may be fixed to one outer side of the peripheral side wall. Also,
It is needless to say that the present invention can be applied to a scanning optical device in an electrophotographic image forming apparatus such as a facsimile and a copying machine, and other optical devices used for image processing and the like. In this case, when the folding mirror has a short length such as a rectangular shape or a square shape in plan view, elastic locking pieces 58,
58, a drop-off preventing piece 59 is provided therebetween, and a pair of elastic locking pieces 58, 58 are provided with a pressing portion 58a and a position regulating portion 5b.
May be configured to be symmetrical.

[0037]

As described above, according to the first aspect of the present invention,
The optical device according to the invention described above is an optical device in which a mirror for changing a path of a light beam is attached to a housing case via a mounting member made of a spring plate. The board is provided so as to be fitted into a drilled mounting hole, and the substrate is provided with a retaining locking claw for locking to a step formed in the mounting hole, while the mirror is mounted on the housing from the rear side thereof. the elastic locking pieces and a position regulating portion for preventing the lateral displacement of the pressing portion and a mirror for pressing against the reference support portion provided on the case before Symbol substrate is obtained integrally provided.

Therefore, by simply inserting the board of the mounting bracket into the mounting hole of the housing case, the retaining locking claw of this substrate can be locked to the step in the mounting hole and cannot be removed. . The pressing portion of the elastic locking piece of the substrate presses the rear surface of the mirror toward the reference support portion of the housing case, and the locking latch claw is locked to the step portion, so that the mirror is rattled. And can be fixed to the housing case. Moreover, the position regulating portion in the elastic locking piece, Ru can be prevented from moving displacement of the mirror in the horizontal direction.

[0039] As this, according to the present invention, while there shall be attached to one mounting bracket to the housing case in one-touch, not only presses the mirror based support unit also prevents Re not a horizontal It is possible to achieve a plurality of functions (actions).

An optical device according to a second aspect is the optical device according to the first aspect.
The optical device according to claim 1, wherein the mounting plate is made of a spring plate.
In addition, the mirror is prevented from falling out of the housing case.
A drop-off prevention piece for stopping is further provided.

Therefore, according to this configuration, the mounting metal
The fixture is provided with a drop-off prevention piece so that the housing
Even if impact force acts on the case, etc., the mirror can be
It does not come off.

The optical device according to the third aspect is the first or the second aspect.
The optical device according to claim 2, wherein in the vicinity of the mounting holes in the housing case, the guide piece for guiding and supporting the back of the substrate of Preparative securing fixture is obtained form standing 設形.

[0043] According to this configuration, at the time of fixation of the mirror abuts the back of the substrate to the guide piece, because the bending deformation of the substrate to the guide-way is restricted, the thickness of the substrate and the elastic latching pieces Even if the mirror is thin, there is an effect that the mirror can be firmly pressed and fixed.

The optical device according to the fourth aspect is the third aspect.
In the optical device of (1), the guide piece is provided with the retaining member.
Guide grooves for guiding the pawls to the step are further provided.
It is.

According to this configuration, the housing case is
Lock when inserting the board into the mounting hole
Insert the board with the claws along the guide groove of the guide piece.
The effect is that it can be mounted securely and easily without error.
Is played.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a laser printer.

FIG. 2 is a side sectional view of the scanning optical device.

FIG. 3 is a view taken along line III-III in FIG. 2;

FIG. 4 is a plan view of a main part.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a perspective view of a mounting portion of a mounting bracket and a housing case.

FIG. 7 is a cross-sectional view showing a housing case mounting portion to the main body frame.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 printer 18 scanner unit 20 laser light emitting unit 21 fθ lens 23 folding mirror 24 cover plate 25 writing signal mirror 26 BD detection sensor 27 rotating polygon mirror 30 housing case 30 a top plate 54 first reference support 55 second reference support 56 Mounting bracket 57 Substrate 57a Retaining locking claw 58 Elastic locking piece 58a Pressing section 58b Position restricting section 59 Fall-off prevention piece 65 Mounting hole 65a Step 66 Guide piece 66a Guide groove

Claims (4)

(57) [Claims] In an optical apparatus in which a mirror for changing the course of a light beam is attached to a housing case via a mounting member made of a spring plate, a substrate of a mounting member made of a spring plate is perforated in the housing case. The board is provided so as to be fitted into a mounting hole, and the substrate is provided with a retaining locking claw for locking to a step formed in the mounting hole, and the mirror is provided on the housing case from the back side thereof. optical apparatus being characterized in that provided integrally with the front Stories substrate a resilient locking piece provided with a position regulating portion for preventing the lateral displacement of the pressing portion and a mirror for pressing against the reference support portions. 2. A mounting plate made of a spring plate, comprising:
Prevents the mirror from falling out of the housing case
A drop-off preventing piece is further provided.
2. The optical device according to 1. Wherein the in the vicinity of the mounting holes in the housing case, preparative with claim 1 or claim a guide piece for guiding and supporting the back of the substrate of metal, characterized in that form standing 設形 2 optical device according to. 4. The retaining piece is provided on the guide piece.
A guide groove for guiding to the step portion is further provided.
The optical device according to claim 3, wherein