JP2002341271A - Deflecting scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a BD slanting slit plate in an optical box for a multi-beam laser and to facilitate BD writing timing adjustment. SOLUTION: The optical box is provided with a positioning means for arranging the BD slanting slit at a specific position and a fixing means for fixing it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection scanning apparatus using a multi-beam laser used for an image forming apparatus such as a laser beam printer and a laser facsimile.

[0002]

2. Description of the Related Art In recent years, the use of a plurality of light sources has been studied along with the high performance and high functionality of an image forming apparatus.
In particular, the use of multi-beam lasers having a plurality of laser emission points is increasing.

FIG. 5 shows a conventional deflection scanning apparatus. A light source unit S0 includes a multi-beam laser 101 having a plurality of laser emission points, and a plurality of laser beams emitted from the multi-beam laser 101. Laser beam L0, for example, in the case of two beams, two laser beams A and B are collimated by a collimator lens 101a, condensed into a linear beam by a cylindrical lens 102, and incident on a reflection surface of a polygon mirror 103. I do.

The polygon mirror 103 is rotated at a high speed by the rotation of a motor 107 rotating at a high speed. The reflected light is deflected and scanned to form an image on a photosensitive drum on a rotating drum Do via an imaging lens 104.

A part of the laser light deflected by the polygon mirror 103 is reflected by the BD mirror 105, passes through the BD slit 106a, and passes through the condenser lens 106b
And enters the BD sensor 106c.

The plurality of laser beams incident on the BD sensor are converted from optical signals into electrical signals in a processing circuit, and are transmitted to the multi-beam laser 101 as scanning start signals. After receiving the scanning start signal, the multi-beam laser 101 starts writing modulation based on image information transmitted from the host computer.

[0007]

However, in the above conventional example using a multi-beam laser, the laser light emitted from a plurality of laser emission points may have a BD timing shift between the plurality of beams for various reasons. As a result, image defects occur due to a periodic writing position shift.

For example, as shown in FIG. 8, when a horizontal line is created by two laser beams A and B, the left side is a normal image, and the right side is two beams, and the writing start position is periodic by ΔL mm. Shows a defective image when the writing position is shifted.

As a countermeasure method, means for electrically adjusting the BD writing timing of each of the multi-beams by an electric means and a slit of a BD slit plate through which a plurality of multi-beams pass to the BD sensor are provided. There is a mechanical means for tilting by an angle.

The present invention is directed to a mechanical means for inclining the slit of the BD slit plate by a predetermined angle,
This realizes a method for easily configuring the D slit plate at a predetermined position of the optical box.

[0011]

In order to achieve the above object, a deflection scanning apparatus according to the present invention comprises a sheet-shaped BD slit plate having a BD slit formed at a predetermined inclination angle with respect to the scanning direction of a scanning lens. A positioning means for arranging the BD slit at a predetermined position in the optical box and a fixing means for patch-locking by a fixing elastic arm extending from the optical box. It is characterized by.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 and 2 show an embodiment of the present invention, FIG. 1 is a main sectional view, and FIG. 2 is a top view thereof.

Since the configuration of the entire apparatus is the same as that of the conventional example, a detailed description is omitted.

In the figure, reference numeral 1 denotes an optical box formed of a resin material;
a is an abutting reference wall for positioning, 1b is a bullet arm for locking a patch formed integrally with the optical box, 2 is a BD slit plate formed of a pressed member made of a sheet metal material, and 2a is a scanning direction of a scanning lens. A BD slit inclined at a predetermined angle with respect to the BD slit;
c is a BD sensor.

As shown in FIG. 3, the inclination angle of the BD slit 2a provided on the BD slit plate 2 is set to a predetermined required angle.

For example, when the inclination angle of the BD slit indicated by the solid line is changed to the inclination angle indicated by the two-dot chain line, the BD of each laser spot of a plurality of multi-beam laser beams is changed.
The timing of passing through the slit changes, and the timing of the time when the light enters the BD sensor 106c changes.

For example, in the case of two laser beams A and B, the laser light passing through the BD slit 2a is received by the BD sensor 106c, and an electric signal having a rising waveform as shown in FIG. 4 is output.

In FIG. 4, L is the slice level, and T is the time interval between the two laser beams A and B when they are converted into electric signals by the BD sensor and output. .

When the inclination angle of the BD slit in FIG. 3 is increased from 2a indicated by the solid line to 2a1 indicated by the two-dot chain line, the time interval T between A and B is extended to T1.

As shown in FIGS. 1 and 2, the BD slit plate 2 is provided on a positioning abutment reference wall 1 a provided on the optical box 1.
Is pressed against and inserted into the optical box 1 so that the patch arm locking arm 1b formed integrally with the optical box 1 can hold and fix the BD slit plate 2.

As a result, the BD can be easily and accurately positioned.
The slit plate 2 can be mounted on the optical box 1.

Further, the present invention can be used for various apparatuses only by changing the BD slit plate in accordance with the BD timing of the multi-beam to be used.

(Second Embodiment) FIG. 3 is a main sectional view showing a second embodiment of the present invention, and FIG. 4 is a perspective view of a BD slit plate.

Since the configuration of the entire apparatus is the same as that of the first embodiment, a detailed description is omitted.

In the figure, reference numeral 3 denotes an optical box formed of a resin material;
Reference numeral a denotes an abutting reference wall for positioning, reference numeral 4 denotes a thin BD slit plate made of a sheet metal material and has an elastic force, and reference numeral 4a denotes a resilient arm for integrally fixing a patch. In the above configuration, the positioning abutment reference wall 3 provided on the optical box 3.
By simply inserting the BD slit plate 4 into a, the patch is fixed by the locking arm 4a.

Compared with the first embodiment, there is no need to provide a resilient arm for locking in the optical box, and the optical box may have a simple shape. In addition, because of the springy thin plate, the locking force can be increased as compared with the resin arm.

[0027]

As described above, according to the present invention, (1) an expensive electric circuit which can be used for various devices only by replacing the BD slit plate in accordance with the BD timing of the multi-beam to be used. This eliminates the need for troublesome electrical adjustment means, and realizes a low-cost mechanical means.

(2) The BD slit plate can be easily and accurately mounted on the optical box.

As described above, a low-cost and highly reliable deflection scanning device can be realized, the timing between multiple beams can be easily adjusted, and a high-quality image can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view according to a first embodiment of the present invention.

FIG. 2 is a top view according to the first embodiment of the present invention.

FIG. 3 is a sectional view according to a second embodiment of the present invention.

FIG. 4 is a perspective view according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram according to the first embodiment of the present invention.

FIG. 7 is a top view showing a conventional example.

FIG. 8 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 optical box 1a abutment reference wall 1b bullet arm 2 BD slit plate 2a BD slit 106b BD lens 106c BD sensor

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G02B 7/00 H04N 1/036 Z 5C072 H04N 1/036 B41J 3/00 D 1/113 H04N 1/04 104A F-term ( Reference) 2C362 AA07 AA10 BA04 BA48 BB30 BB31 BB38 2H042 AA09 AA15 AA24 2H043 AE18 AE23 2H045 AA01 BA22 BA33 CA88 CA98 DA02 5C051 AA02 CA07 DB00 DB02 DB22 DB24 DB30 DC04 DC07 DE02 5C072 AA03 HA02BAO

Claims (4)

[Claims] 1. A light source unit having a plurality of laser emission points, a deflection scanning means for deflecting a plurality of laser beams emitted from the light source unit by a polygon mirror and forming an image with a scanning lens, and writing the plurality of laser beams A device in which synchronization detection means for controlling the start synchronization by a horizontal synchronization signal is housed in an optical box. A BD sensor for receiving the laser beam of the synchronization detection means and a BD slit plate for passing the laser beam to the BD sensor are provided in the optical box. Stored in the BD
A deflection scanning device, wherein a BD slit provided in a slit plate is formed in a slit shape inclined at a predetermined angle θ with respect to a scanning direction of a scanning lens, and at an angle of 0 ° <θ <90 °. 2. The deflecting device according to claim 1, wherein the optical box is provided with positioning means for arranging the BD slit plate at a predetermined position and fixing means for locking the BD slit. Scanning device. 3. The deflection scanning device according to claim 1, wherein an elastic arm for patch-locking the BD slit is integrally provided in the optical box. 4. The BD slit plate is formed of a thin sheet metal member having elasticity, and a locking portion for locking the patch is integrally formed by an extended portion of the BD slit plate. The deflection scanning device according to claim 1.