JPS6197620A - Rotary polygon mirror - Google Patents

Abstract

PURPOSE:To sharply improve the influence of the contamination of a mirror surface and at the inside of a motor due to dust in the atmosphere, by making clean air to flow into a space formed by brackets from vent windows through dust-proof filters and cooling the motor with the air. CONSTITUTION:When a rotary polygon mirror 41 is rotated by means of an outer rotor motor 43, air flows are produced in the tangential direction of the periphery of the mirror 41 and negative-pressure conditions are produced in brackets 50 and 51 acting as covers. Therefore, clean air flows into a space formed by the brackets 50 and 51 from vent windows 58 and 59 through filters 60 and 61 and cools the motor 43. Since the motor 43 and rotary polygon mirror 41 rotate in the air flow flowing into the space from the vent windows 58 and 59 and the dust-proof filters 60 and 61 are provided at the windows 58 and 59, the invasion of dust incorporated in the outside air into the motor 43 can be prevented sufficiently. Moreover, since the plane reflecting mirrors of the rotary polygon mirroor 41 are arranged around the rotating peripheral surface of a rotor, the whole constituting body including the motor can be miniaturized relatively.

Description

Detailed Description of the Invention (Industrial Application IP) This invention is an information recording method in which a light beam whose light intensity is modulated by an information signal is converted into a scanning light, and this is projected and recorded onto a photosensitive recording medium. This invention relates to a rotating polygon mirror used in an optical scanning system of an apparatus.

(Prior Art) As this type of information recording device, a so-called laser printer device that prints using, for example, a laser beam as a light beam is well known.

FIG. 2 is a diagram showing the main parts of a typical configuration example of a laser COM, which is a type of laser printer device.

Here, in order to facilitate understanding of the present invention, Masuso's laser COM will be briefly explained.

The laser OOM is a computer output microfilm device that uses a laser as a scanning light to record print data (variable information) from a computer on a microform together with desired form data (fixed information).

1 is an argon (Ar) laser for recording;
The light beam of the back edge color is intensity-modulated by a video signal to be described later by a light modulator z, and then passes through a first dichroic mirror 3. On the other hand, the red laser beam from the reading helium neon laser 4 passes through the first reflecting mirror 5 and enters the first dichroic mirror 8, where it is reflected.
It is combined with the recording light beam that has passed through the first dichroic mirror 3 and enters the rotating polygon mirror 7 via the second reflecting mirror 6. In this case, the first dichroic mirror 8 is configured to transmit evening light and green light and reflect red light.

The rotating polygon mirror 7 is rotated at a constant speed in a predetermined direction by a motor 9 which is rotated by electric power supplied from a rotating mirror drive circuit 8. Therefore, the combined light beam incident on each mirror surface of the rotating polygon mirror 7 is reflected and deflected (hereinafter referred to as "horizontal deflection") by each mirror surface, and is one-dimensional with a repetition period for each reflected light beam by each mirror surface. After being converted into a combined light beam as scanning light, the light passes through a focusing optical system 10 and enters a second dichroic mirror 11 . The second dichroic mirror 11 has a characteristic of transmitting back edge color light for recording and red light for reading, and partially reflecting red light for reading. Therefore, among the combined light beams incident on the second dichroic mirror 10, the W green light beam and the red light beam are transmitted toward the galvanometer mirror 12, but a portion of the red light beam is reflected and transmitted to the linear encoder 18. It is also incident on

This galvano mirror 12 is a galvano mirror drive device 14
The recording light beam is deflected in a direction substantially perpendicular to the horizontal deflection direction (hereinafter referred to as "vertical deflection") by a sawtooth drive signal supplied from the recording light beam. The galvanomirror drive device 14 is driven and generates a drive signal based on a clock signal generated from a clock signal generation device 15, which will be described later. For example, this clock signal is generated by a vertical address signal generation circuit 16. A vertical address signal is generated by counting in the vertical deflection period, and the drive device 14 is driven by this address signal to generate a drive signal.

The light beams of back edge color light and red light that are vertically deflected by the galvanometer mirror 12 are converted into one-dimensional scanning light by the rotating polygon mirror 7, and thus become two-dimensional scanning light by this vertical deflection and then sent to the third dichroic mirror 17. The light beams are separated into back-edge color light beams and red light beams.

The two-dimensional scanning light of the light beam of the back edge color light transmitted through the third dichroic mirror 17 is imaged onto a recording material, for example, a film F, by an imaging optical system, and scanned by raster. On the other hand, the other two-dimensional scanning light of red light separated by the third dichroic mirror 17 passes through the third reflecting mirror 19,
The light enters the form slide 20A.

The form slide device zO usually includes a plurality of frequently used form slides 20A and 20B.

... are set, and these form slides 2
0A, 20B,... have different slide images,
For example, different entry frames each consisting of a large number of vertical and horizontal ruled lines are recorded. Then, one of the sheets can be selectively moved to a position where it can be scanned with two-dimensional scanning light. Further, the form slides 20A, 20B, . . . can be arbitrarily attached and detached and replaced as required.

In the illustrated example, there are two form slides 20A and BOB.
5 are set, and the light beam transmitted through one slide 2OA is extracted as an electric signal by the first photomultiplier tube 21. This electrical signal is a video signal corresponding to a frame image consisting of ruled lines and the like.

On the other hand, the red light beam separated by the second dichroic mirror 11 enters the linear encoder 1B and scans it one-dimensionally. This linear encoder 18
A large number of transparent and opaque linear gratings are formed parallel to the horizontal deflection direction and arranged in a striped pattern at equal pitches. A clock pulse signal is extracted by photoelectrically converting the pulsed light obtained by scanning the linear encoder 18 with the horizontally polarized scanning light by the second photomultiplier tube 2z. This clock pulse signal is supplied to a phase-coupled clock oscillator 23 to oscillate a clock signal for synchronizing and timing the operation of each part of the laser OOM. in this case,
The linear encoder 18, the second photomultiplier tube 22, and the clock oscillator z8 constitute the clock signal generator 15.

At the timing of the clock signal obtained by this device 15, character information corresponding to coded data from a character information source such as a magnetic tape is read out as a video signal from a character generator 24, which will be described later. The video signal from this character generator z4 is supplied to a signal synthesis circuit 25. This circuit 25 also includes a first photomultiplier tube 2.
1 is amplified by an amplifier 26 and then waveform-shaped by a level slicer 27. A form signal obtained by amplifying the output from the amplifier 26 is supplied, so that the video signal and the form signal are synthesized here.

The video signal synthesized in this way is modulated by a driving circuit z
8 to a light modulator z, which modulates the intensity of the recording light beam. Therefore, the rask image projected onto the film F is an image in which print data from a computer or the like is written at a predetermined position within the entry frame of the form selected by the form slide. Then, the image is recorded on this film F.

In the scanning optical system of an optical scanning type information recording device including such a laser OOM, the rotating polygon mirror 7, which is one of the main components of the optical scanning system, is generally used for rotating it. It has an integrated structure housed in a case together with the motor 9.

FIG. 3 shows an outline of a conventional configuration example in a perspective view.

That is, the rotating polygon mirror 7 in the conventional information recording device of this type is connected to the rotating shaft 8 of the rotor of the inner rotor type motor 9.
1 and housed in a case 32, and the motor 9 is fixed to this case 3z. The rotational circumference 83 of the rotating polygon mirror 7 is an optical window formed in the case 3z in order to introduce a light beam to the mirror surface of the rotating polygon mirror 7 or to extract a light beam that is incident on the mirror surface and reflected. .

(Problems to be Solved by the Invention) Generally, this type of rotating polygon mirror is used in a high-speed rotation state. In addition, as shown in FIG. 8, a sealed case 82
The temperature of the rotary drive motor 9 tends to rise because the machine is busy at home.

Furthermore, due to the high-speed rotation, the atmosphere is pushed in the direction of rotation by the adjacent mirror-surface joint top 84, so the atmosphere in the rear region of the joint top 84 becomes negative pressure, and grease, etc. scattered from the bearings is collected here. Lubricant particles and dust in the atmosphere are sucked in and adhere to the mirror surface in the negative pressure area.
There were problems such as causing pollution.

(Means for Solving the Problems) An object of the present invention is to provide a rotating polygon mirror having a novel configuration that can solve the problems of the conventional rotating polygon mirrors as described above.

The rotating polygon mirror of the present invention uses an outer rotor type motor as a rotational drive source, and has a large number of flat reflecting mirrors arranged in a polygonal shape on the circumferential surface of the rotor along the rotation direction of the rotor of the motor, and fixed By means of a bracket that fixedly supports the child inside the rotor, both sides including the reflecting plane mirror mounting part are sealed and enclosed so that only the mirror surface of the plane reflecting mirror is exposed. It is characterized by having a ventilation window equipped with a dust filter on one side.

(Function) According to this configuration, the bracket is formed in a sealed structure so that only the mirror surface of the plane reflector attached to the rotor is exposed, and the ventilation window is provided in the bracket, so that the rotation The rotation of the child creates a negative pressure inside the bracket, causing atmospheric air to flow into the bracket, thereby producing a cooling effect. Furthermore, since the bracket is provided with a filter, contamination inside the motor can be prevented.

(Example) This invention will be described in detail below based on examples.

FIG. 1(A) shows the configuration of one embodiment of the present invention along the center line Y
A partial cross-sectional view is shown with the boundary between 2 and 3, and drawing (B) is an external appearance view thereof.

In both of these figures, 41 is a rotating polygon mirror.

The rotating polygon mirror 41 has a structure in which a large number of plane reflecting mirrors 44 are attached to a yoke part, that is, a rotor 42 of a so-called outer rotor type motor 48 in which a yoke part 4z of an outer frame rotates. That is, each plane reflecting mirror 44 is connected to the rotor 4
They are arranged in a polygonal shape in the direction along the rotational circumferential side of the rotor 4z by mirror mounting members 45 fixed to the rotor 4z,
It rotates as the rotor 42 rotates. 46 is a stator;
A bearing 4 is provided on the fixed shaft 47 so that the rotor 42 rotates about the center line X of the fixed shaft 47.
8 supports the rotating shaft 47 of the rotor 4z.

50 and 51 are brackets having fixed bearing parts 52 and 53 that hold and fix the fixed shaft 47 of the stator 46.

The rotor 42 is surrounded from both sides by exposing only the mirror surfaces of the brackets 52 and 58 so that there is no problem with the input and reflection of incident light from the outside on the plane reflecting mirror 44 of the rotating polygon mirror 41 of the brackets 52 and 58. An outer rotor type motor 43 consisting of a rotor 42 and a stator 46 is hermetically sealed by this bracket.

Further, at mutually opposing ends of each bracket 50 and 51, a flange portion 54 having a diameter larger than the outer circumferential diameter of the rotating polygon mirror 4.1 is provided.
, 55 are fixedly installed, the atmosphere inside the motor 48 is sufficiently discharged to the outside as the rotating polygon mirror 41 rotates. In addition, 56, 5? is a pin for fixing the fixed shaft 47 to the fixed bearing parts 52 and 58. Further, each of the brackets 50 and 51 is provided with a plurality of ventilation windows 58 and 59. In this example,
Although the ventilation windows 58 and 59 are shown as being formed concentrically with respect to the axis, they may be installed at any location, for example, on the peripheral sides of the brackets 50 and 51. Dust filters 60 and 61 are attached to each of these ventilation windows 58 and 59, respectively.

In the configuration of the rotating polygon mirror as described above, when the rotating polygon wire 41 rotates due to the rotation of the motor 48, an air current is generated in a substantially tangential direction of the circumferential surface, and the inside of the brackets 50 and 51 forming the cover is in a negative pressure state. become.

Therefore, clean air flows through the dust filters 60 and 61 from the ventilation windows 58 and 59 to the brackets 50 and 51.
The air flows into the space formed by the air, and this becomes a continuous air flow that cools the motor.

That is, the motor 48 and the rotating polygon mirror 41 rotate in the airflow of the atmosphere flowing in through the ventilation windows 58 and 59, and since the ventilation windows 58 and 59 are equipped with dust filters 60 and 61, outside air is Intrusion of dust inside the motor 48 can be sufficiently prevented.

(Effects of the Invention) According to the present invention, not only can a sufficient cooling effect be obtained against the temperature rise of the motor that rotates the rotating polygon mirror, but also
Since the air passing through the interior of the motor and the mirror surface of the rotating polygon mirror is cleaned by the dust filter, the influence of contamination of the mirror surface and the interior of the motor due to dust in the atmosphere can be greatly reduced.

Moreover, an outer rotor type motor is used as the rotational swivel power source,
Since the individual plane reflecting mirrors of the rotating polygon mirror are arranged on the rotating peripheral surface of the rotor, there is an effect that the entire groove assembly including the motor can be made relatively compact.

[Brief explanation of drawings]

FIG. 1(A) is a front view partially showing an example of the configuration of an embodiment of the present invention, FIG. 1(E) is a side view of FIG. 1(A), and FIG. FIG. 8 is a diagram showing a schematic configuration of an example of an optical travel type information recording device using a rotating polygon mirror. FIG. 8 is a perspective external view showing an example of sweeping of a conventional rotating polygon mirror. 41...Rotating polygon mirror 42...Rotor 48.
...Outer rotor type motor 44...Flat reflecting mirror 45...Mirror mounting member 46...Stator 47...Fixed shaft 48...
・・Bearing 49 ・Rotating shaft 50 , 51 ・
... Bracket) 52.58 ... Fixed bearing part 54
, 55... Flange portion 56, 57... Fixed bottle 58, 59... Ventilation window 60, 61.
...Dust-proof filter. Patent applicant: Fuji Photo Film Co., Ltd. Figure 2F Figure 3

Claims (1)

[Claims] 1. An outer rotor type motor is used as a rotational drive source, and a large number of plane reflecting mirrors are arranged in a polygonal shape on the circumferential surface of the rotor along the rotation direction of the rotor of the motor, and a stator is attached to the rotor. Both sides, including the reflecting plane mirror mounting part, are hermetically surrounded by a bracket fixedly supported inside so that only the mirror surface of the plane reflecting mirror is exposed, and at least one of the brackets is provided with a dustproof filter. A rotating polygon mirror characterized by having a ventilation window.