JPH1172728A - Multi-beam deflecting and scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the inclination of the side wall of an optical box during the adjusting work of a beam interval. SOLUTION: A multi-beam source unit 1 for generating plural laser beams is integrally formed by a laser holder 11a incorporating a multi-beam laser and a lens barrel 12a for holding a collimator lens 12, etc., before screwing it to the side wall 8a of an optical box 8, by pushing the head T of a rotary jig on the laser holder 11a and rotating it, the adjustment of a beam interval is performed. Since there is a fear of tilt of the side wall 8a of the optical box 8 by the pressing force of the rotary jig during the work, a reinforced rib 9a is provided in the portion exerted by the pressing force and its rigidity is strengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-beam deflection scanning device used for a laser beam printer, a digital copying machine, and the like.

[0002]

2. Description of the Related Art In recent years, in order to increase the recording speed of a laser beam printer, a digital copying machine, or the like, a multi-beam deflection scanning apparatus for simultaneously writing a plurality of lines using a plurality of laser beams has been developed.

In this method, a plurality of laser beams separated from each other are simultaneously scanned. As shown in FIG. 9, for example, two laser beams (light beams) are generated from a multi-beam light source unit 101, and these are generated. After being collimated by a collimator lens, the light is radiated to the reflecting surface of a rotary polygon mirror 103 via a cylindrical lens 102, and is imaged on a photosensitive member of a rotating drum (not shown) via an image forming lens 104 and a folding mirror 105.

The two laser beams are incident on the reflecting surface of the rotating polygon mirror 103 in a state where they are separated from each other in the direction along the rotation axis of the rotating polygon mirror 103 (Z-axis direction), and the main scanning direction is orthogonal to the Z axis. (In the Y-axis direction) and the rotating polygon mirror 10
An electrostatic latent image is formed on the photoconductor along with the main scanning in the Y-axis direction by the rotation of No. 3 and the sub-scanning in the Z-axis direction by the rotation of the rotary drum.

[0005] The cylindrical lens 102 condenses each laser beam linearly on the reflection surface of the rotary polygon mirror 103. This is because the point image formed on the photoreceptor
It has a function of preventing distortion from occurring due to the tilting of the rotary polygon mirror 103. The imaging lens 104 includes a spherical lens portion and a toric lens portion, which have a function of preventing distortion of a point image on the photoconductor similarly to the cylindrical lens 102, and that the point image is formed on the photoconductor. It has a so-called Fθ function that corrects scanning at a constant speed in the main scanning direction.

[0006] The two laser beams are separated by a detection mirror 106 below the main scanning plane at the end of the main scanning plane (XY plane) in the Y-axis direction, introduced into the optical sensor 107, and written by the controller. It is converted into a start signal and transmitted to the multi-beam light source unit 101. Upon receiving the write start signal, the multi-beam light source unit 101 starts writing modulation of each laser beam.

By adjusting the timing of the write modulation of each laser beam in this manner, the write start (write) position of the electrostatic latent image on each line formed on the photosensitive member is controlled.

[0008] The cylindrical lens 102, rotating polygon mirror 103, image forming lens 104, folding mirror 105 and the like are assembled on the bottom wall of the optical box 108. After assembling the optical components into the optical box 108, the upper opening of the optical box 108 is closed by a lid member (not shown).

The multi-beam light source unit 101 is shown in FIG.
As shown in FIG. 3, the laser beam source includes a multi-beam laser 110 that emits a plurality of laser beams simultaneously.
12 as an integrated unit with the optical box 1
08 side wall 108a.

Before fixing the laser holder 111 to the optical box 108, a rotating jig (not shown) is pressed against the laser holder 111 as shown by an arrow A while emitting the multi-beam laser 110, and is rotated around its central axis. Rotation is performed to adjust the angle in the arrangement direction (laser array) of the emission points of the plurality of laser beams of the multi-beam laser 110, and to adjust the beam interval so that the interval between the writing lines on the photoconductor matches the design value. Is performed.

[0011]

However, according to the above prior art, when assembling the multi-beam light source unit to the optical box as described above, the multi-beam light source unit is rotated while emitting the multi-beam laser. It is necessary to adjust the beam interval between a plurality of laser beams.
If the laser holder or the like is directly gripped and rotated by hand, workability is poor and extremely inefficient. Therefore, a method is employed in which the rotary jig is pressed against the laser holder to rotate it. At this time, due to the pressing force acting on the laser holder, as shown by a broken line in FIG. There is an unsolved problem that the beam 108a falls inward and the beam interval cannot be adjusted accurately.

In recent years, an optical box made of resin is often used for cost reduction and weight reduction. In such a case, the side wall of the optical box is relatively soft. For this reason, when the rotating jig for adjusting the beam interval is pressed, the side wall of the optical box is elastically deformed as shown by the broken line in FIG. 8, and when the pressing force of the rotating jig is released after the adjustment, the original Return to shape. That is, even if the beam spacing on the surface of the rotating drum is adjusted to a predetermined value using the rotating jig, the optical axis of each laser beam is pressed because the rotating jig is pressed and the side wall of the optical box is elastically deformed. The direction changes, and as a result, the incident position on the imaging lens shifts, the imaging position on the rotating drum changes, and this greatly affects the beam interval.

The accuracy of the beam interval on the rotating drum must be controlled very strictly so that the allowable value of the error is several μm or less. If the side wall of the optical box is tilted during the adjustment of the beam interval as described above, it is sufficient. Accuracy cannot be achieved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has a high performance in which the beam interval between a plurality of light beams can be adjusted very simply, quickly and with high precision. It is an object of the present invention to provide a multi-beam deflection scanning device.

[0015]

In order to achieve the above object, a multi-beam deflection scanning apparatus according to the present invention comprises: a light source for generating a plurality of light beams; a light source holding member for holding the light beam; Scanning means for deflecting and scanning the beam, and an optical box for accommodating the scanning means, wherein the light source holding member is supported on a side wall of the optical box, and the side wall reduces a beam interval between the plurality of light beams. It is characterized in that a projection is provided for locally increasing the rigidity at a portion where the pressing force of the rotating jig for rotating the light source acts for adjustment.

It is preferable that a cylindrical portion for covering the light source holding member is provided integrally with the projecting portion of the side wall of the optical box.

[0017]

In the multi-beam light source unit, the beam interval is adjusted by rotating the light source for generating a plurality of light beams relatively to the side wall of the optical box. This adjustment operation is performed in a step of assembling the light source holding member holding the light source to the optical box, and is easily and quickly performed by pressing the rotating jig against the light source holding member temporarily fixed to the side wall of the optical box and rotating it. . However, if the rigidity of the side wall of the optical box is low, the side wall is inclined by the pressing force of the rotating jig, and the optical axis direction of each light beam changes, resulting in a significant error.

Therefore, a projection is provided on the side wall of the optical box at a position where the pressing force of the rotating jig acts, and the rigidity of the side wall is locally enhanced. Thereby, it is possible to avoid inclination of the side wall of the optical box during the adjustment operation of the beam interval, and to obtain sufficient accuracy.

[0019]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a multi-beam deflection scanning apparatus according to an embodiment. The multi-beam deflection scanning apparatus includes two light beams, ie, laser beams P ₁ and P ₁ from a multi-beam laser 11 as a light source of a multi-beam light source unit ₁ . P ₂ is generated,
After being collimated by a collimator lens 12, the light is irradiated on a reflecting surface 3 a of a rotary polygon mirror 3, which is a scanning means, via a stop 13 and a cylindrical lens 2, and is passed through an image forming lens system 4 on a rotating drum 5. Image.

The two laser beams P ₁ and P ₂ are incident on the reflecting surface 3a of the rotary polygon mirror 3 in a state of being separated in a direction (Z-axis direction) along the rotation axis of the rotary polygon mirror 3, and respectively enter the Z-axis. Is scanned in the main scanning direction (Y-axis direction) orthogonal to the direction of the arrow. Form a latent image.

The cylindrical lens 2 condenses each of the laser beams P ₁ and P ₂ linearly on the reflecting surface 3 a of the rotary polygon mirror 3. This has the function of preventing the point image formed on the photoreceptor from being distorted due to the tilting of the rotary polygon mirror 3 as described above, and the imaging lens system 4 includes a spherical lens 4a. And a toric lens 4b.
Like the cylindrical lens 2, it has a function of preventing distortion of a point image on the photoconductor, and a function of correcting the point image so as to be scanned at a constant speed in the main scanning direction on the photoconductor.

The two laser beams P ₁ and P ₂ are respectively separated below the main scanning plane by the detection mirror 6 at the end of the main scanning plane (XY plane) in the Y-axis direction, and traverse the main scanning plane. The light is introduced into the optical sensor 7 on the opposite side, converted into a write start signal by a controller (not shown), and transmitted to the multi-beam laser 11. The multi-beam laser 11 receives the write start signal and
_1, starts the write modulation P _2.

By adjusting the timing of the write modulation of the laser beams P ₁ and P _{2 in} this manner, the write start (write) position of the electrostatic latent image formed on the photosensitive member is controlled.

A cylindrical lens 2, a rotary polygon mirror 3,
The imaging lens system 4 and the like are mounted on the bottom wall of the optical box 8 shown in FIG. After assembling each optical component to the optical box 8, the upper opening of the optical box 8 is closed by a lid member (not shown).

The multi-beam laser 11 emits a plurality of laser beams at the same time as described above. As shown in FIG. 2, a lens barrel incorporating a collimator lens 12 via a laser holder 11a serving as a light source holding means. The optical box 8 is assembled to the side wall 8a as a unit integrally connected to the optical box 12a.

When assembling the multi-beam light source unit 1, the laser holder 11 a holding the multi-beam laser 11 is attached to the opening 8 b provided on the side wall 8 a of the optical box 8.
Into the laser holder 11a and the collimator lens 12
After adjusting the focus and the optical axis of the collimator lens 12 by covering the lens barrel 12a, the lens barrel 12a is bonded to the laser holder 11a. Subsequently, the laser holder 11
By rotating a as shown by an arrow R (see FIG. 5), the arrangement direction of the laser array is adjusted, and the two laser beams P ₁ and P generated from the multi-beam laser 11 are adjusted.
A so-called beam interval adjustment operation for matching the beam interval ΔP of ₂ with the design value on the rotating drum 5 is performed.
Tighten the screw 11b and place the laser holder 11a in the optical box 8
To the side wall 8a.

Inside the side wall 8a of the optical box 8, there are provided a pair of reinforcing ribs 9a which protrude in the optical axis direction from the side of the opening 8b. The rigidity of 8a is locally enhanced. Outside the side wall 8a, a pair of pedestals 9b protruding from the back side of each reinforcing rib 9a in the optical axis direction is disposed, and the plate-shaped portion of the laser holder 11a is brought into contact with them (see FIG. 3). ).

A pair of heads T of the rotary jig for adjusting the beam interval is pressed against the laser holder 11a from outside each pedestal 9b. Since the reinforcing ribs 9a for enhancing the rigidity in the optical axis direction are provided inside each pedestal 9b, each reinforcing rib 9a is only compressed by the pressing force of the rotating jig, and the optical ribs are different from the conventional example. There is no possibility that the side wall 8a of the box 8 is elastically deformed.

Next, a procedure for assembling the multi-beam light source unit 1 to the optical box 8 will be described.

As described above, the cylindrical portion of the laser holder 11a that holds the multi-beam laser 11 is inserted into the opening 8b of the side wall 8a, and the plate-shaped portion of the laser holder 11a contacts the pedestal 9b. The lens barrel 12a of the collimator lens 12 is placed over the tip of the laser holder 11a, and focus adjustment and optical axis alignment of the collimator lens 12 are performed.
Is adhered to the laser holder 11a. Subsequently, the head T of the rotating jig is pressed against the laser holder 11a and rotated, thereby adjusting the beam interval on the rotating drum 5. The head T of the rotating jig vertically holds the laser holder 11a,
By pressing the same height as the pedestal 9b, the entire laser beam light source unit 1 is pressed against the side wall 8a. This is because the screw 11b is used to adjust the laser holder 11 after rotation adjustment.
This is for the same as in the state where a is assembled to the optical box 8.

Since the reinforcing rib 9a is provided at the same height as the pedestal 9b, the rotating jig compresses the reinforcing rib 9a. That is, the pressing force applied to the optical box 8 by pressing the head T of the rotating jig only compresses the reinforcing rib 9a, and the deformation of the side wall 8a of the optical box 8 hardly occurs. In this state, by rotating the multi-beam light source unit 1 around its optical axis,
Adjust the interval (beam interval) between scanning lines on the photoconductor. After adjusting the beam interval, the screw 11b is tightened to release the pressing of the rotating jig, and the assembly is completed.

According to the present embodiment, by preventing the optical box from being deformed by the rotating jig, it is possible to prevent the occurrence of an error due to the deformation of the optical box returning when the pressing force of the rotating jig is released, and to prevent the beam from being deformed. The interval can be adjusted with extremely high precision.

The use of the rotary jig improves the efficiency of beam spacing adjustment work, reduces assembly costs, and achieves sufficient accuracy. Therefore, the performance and cost of the multi-beam deflection scanning device are reduced. Can greatly contribute to

FIGS. 6 and 7 show a modification. This is configured such that a cylindrical portion 9c integral with the reinforcing rib 9a is disposed on the side wall 8a of the optical box 8, and the cylindrical portion 9c covers around the laser holder 11a. The cylindrical portion 9c further enhances the rigidity of the optical box 8 together with the reinforcing ribs 9a, and prevents the outside air from entering through the opening 8b of the optical box 8, thereby enhancing the dustproofness of the optical box 8,
It serves to prevent the internal rotating polygon mirror 3 and the imaging lens system 4 from being contaminated by floating dust and the like.

As a result, it is possible to greatly contribute to further improving the accuracy of the multi-beam deflection scanning device, reducing maintenance costs and extending the service life.

[0037]

Since the present invention is configured as described above, the following effects can be obtained.

The inclination of the side wall of the optical box can be avoided, and the operation of adjusting the beam interval can be performed very simply, with high accuracy, and quickly. This greatly contributes to the cost reduction and high accuracy of the multi-beam deflection scanning device.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a multi-beam deflection scanning device according to an embodiment.

FIG. 2 is an exploded perspective view showing only a multi-beam light source unit of the apparatus of FIG. 1 in an exploded manner.

FIG. 3 is a sectional view showing a second device.

FIG. 4 is a sectional view showing the second device in an assembled state.

FIG. 5 is a diagram illustrating an operation of adjusting a beam interval.

FIG. 6 is an exploded perspective view showing a modification.

FIG. 7 is a sectional view showing the device of FIG. 6;

FIG. 8 is a partial schematic cross-sectional view showing a multi-beam light source unit according to a conventional example.

FIG. 9 shows the entire multi-beam deflection scanning apparatus of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-beam light source unit 2 Cylindrical lens 3 Rotating polygon mirror 4 Imaging lens system 8 Optical box 9a Reinforcement rib 9b Base 9c Cylindrical part 11 Multi-beam laser 11a Laser holder 11b Screw 12 Collimator lens

Claims (2)

[Claims] A light source that generates a plurality of light beams, a light source holding member that holds the light beams, a scanning unit that deflects and scans the plurality of light beams, and an optical box that houses the scanning unit; The light source holding member is supported on a side wall of the optical box, and the side wall increases rigidity at a portion where a pressing force of a rotating jig for rotating the light source acts to adjust a beam interval of the plurality of light beams. A multi-beam deflection scanning device comprising a protrusion for locally strengthening. 2. The multi-beam deflection scanning device according to claim 1, wherein a cylindrical portion that covers the light source holding member is integrally provided at a protruding portion of the side wall of the optical box.