JPH0572495A - Laser beam printer - Google Patents

Abstract

PURPOSE:To eliminate the adverse influence of dirt upon picture representing performance owing to the sticking of dust on a polygon mirror in operation by providing a scanner motor with a cover made of general resin. CONSTITUTION:A polygon mirror 19 is fixed on the rotor of the scanner motor 18. A holder 25 clamps and holds optical path formation glass 26 made of optical glass and is fitted and elastically mounted in a holder cut part 27b that the cover 27 has and right and left, and upper grooves 27a. The cover 27 and holder 25 are both made of general resin, e.g. polypropylene. The cover 27 has a screw hole 27d and is clamped and fixed to the screw hole 18b of a fitting flange part 18a with a setscrew 28. The cover 27, holder 25, and glass 26 constitute the dust-protective structure of the polygon mirror 19. The thickness of the holder 25 is selected so that a bare hand in not able to touch the glass 26 even when the window part of the holder 25 is picked up with fingers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a scanner motor having a polygon mirror of a laser beam printer,
The present invention relates to a product that solves the problem that dust adheres to a polygon mirror during actual operation, which interferes with regular drawing performance.

[0002]

2. Description of the Related Art The market for laser beam printers of this kind is in the future, and the frequency of use has been small in the past, and it is rare that dust adheres to the polygon mirror during actual operation and the regular printing performance is hindered. Met. Therefore, it was installed naked inside a simple case that surrounds the entire optical system including the lens. This is also advantageous in terms of price, since no parts are required,
As the frequency of use has increased in recent years, defective display in the market is becoming a problem.

This means that it is not easy to restore a once-dirty polygon mirror to the normal drawing state. Cleaning the mirror surface is almost impossible on the market, and the entire motor including the polygon mirror is inevitably replaced. This is not preferable because it imposes a huge burden on the customer.

In the conventional example, Japanese Patent Publication No. 1-28318 (Title of Invention: Laser Unit), Japanese Utility Model Publication No. 63-41.
There are No. 72 (new model name: optical scanning device) etc., but these are not for dirt on the mirror.

Also, there is Japanese Patent Laid-Open No. 58-46317 (the title of the invention: a laser scanning optical system), which is provided with a partition wall around the mirror to prevent wind damage and not to prevent stains.

Further, in Japanese Laid-Open Patent Publication No. 58-220117 (Title of Invention: Optical Deflection Device), a polygon mirror is housed in a casing, but it is required to maintain rotational stability in a vacuum state. Is.

[0007]

SUMMARY OF THE INVENTION As described above, it is an object of the present invention to provide a structure that prevents dust from adhering to a polygon mirror even under various environments. However, due to the mechanism of generation of dirt, the polygon mirror of several thousand to ten thousand revolutions creates positive and negative pressure in the surroundings, which causes the introduction of the outside air and the exhaust flow, and the dust mixed in the outside air is reflected on the mirror surface. It is to attach. Since it is difficult to eliminate the positive and negative pressure of the mirror, it is necessary to prepare a cover for protecting the mirror from the outside air while ensuring the passage of the laser light, but the polygon mirror that rotates from several thousand to ten thousand thousand revolutions vibrates. This is a protective structure that satisfies the three requirements of dust protection, vibration, and noise.

[0008]

[Means for Solving the Problems] This is to prepare a protective cover and mount it in advance. However, in addition to satisfying the above three points, productivity and price must be taken into consideration, and simple mounting is required. I have to.

In terms of productivity, it should be mounted on a scanner motor that has been assembled in the form of a conventional scanner motor.
In terms of price, minimize the number of parts, prepare a molding cover made of general-purpose resin, and further form an optical path window made of optical glass. To hold this glass, a general-purpose resin molding holder is attached by elastic attachment to the cover. With the structure.

[0010]

With the above contents, by mounting the scanner motor so as to surround the polygon mirror of the scanner motor, a simple and inexpensive dustproof structure without vibration can be obtained.

[0011]

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

FIG. 1 is an explanatory view of the overall structure of a laser beam printer. The exterior frame 1 has an optical unit 2 and a reversing mirror storage portion 2a, and the photosensitive drum 13 is provided substantially at the center.
Is located. 3 is a developing unit, 4 is a paper passage portion, 5 is a paper feed roller, 6 is a paper feed cassette, 7 is paper, 8 is a paper ejection tray, 9 is a paper ejection roller, 10 is a fixing unit, 11 is a cleaning unit, Reference numeral 12 is an erase lamp, 15 is a static eliminator, and 16 is a charger.

The laser beam printer consisting of these main units writes a picture on the drum 13 with a laser beam, adheres the toner to the surface of the drum 13 by the developing device 4, transfers it onto the paper, and fixes it with a heater. The unit 10 fixes and discharges the sheet.

The present invention relates to the scanner motor portion inside the optical unit 2 in this, and when explained in detail of each portion from FIG. 2 to FIG. 5, FIG. 2 shows a simple lid on the upper surface of the optical unit. A top view of the state in which the scanner motor 18 having a polygon mirror 19 in the optical box 17, lenses 20, 21, and a condenser lens unit 2 are shown.
2. It has a light emitting unit 23. Polygon mirror 1
In the state of the simple lid attached to the optical box 17, as shown in FIG. 3, the final surface portion 9 of each surface divided into several parts is the worst. Dirty, in this state you can not write a regular picture.

This is because, as described above, the outside air moves due to the rotation of the polygon mirror by several thousand, and dust is also attached at that time.

FIG. 4 is a perspective view in which the scanner motor with the cover attached is exploded for each part. The polygon mirror 19 is fixed to the rotor of the scanner motor 18. 1
Reference numeral 8a is a mounting flange portion, and 18b is a cover mounting screw hole.

Reference numeral 25 denotes a holder for holding the optical path forming glass made of optical glass (even if it is made of resin, there is no problem), and holding notches 27b for the holder in the cover 27, and left and right and upper portions. It is fitted and mounted in the provided groove 27a.

This is a holder 2 part 2 on the other side in order to sandwich it.
5a and both are connected by a thin part 25d,
Glass holding portion 25c having a step on the surface of the window portion 25b
To form a groove 26a.
It is intended to be attached to the. Cover 27, holder 25
Both of them can be made of general-purpose resin, so-called polypropylene, etc., they have good moldability, they are cheap, and they are easy to land on.

FIG. 5 is a partial cross-sectional view of this optical path portion, showing in detail the relationship between the groove 27a, the glass 27 and the holder 25. 28 is a set screw, which is discharged from the cover,
It is a mounting portion having a screw hole 27d. It is fixed by being tightened in the screw hole 18b formed in the flat mounting flange portion 18a.

[0020]

As described above, the dustproof protection structure of the polygon mirror, which is composed of the cover 27, the holder 25, and the glass 26 made of general-purpose resin, can be manufactured at a low price and can be assembled and manufactured in the conventional scanner motor. It has a structure that can be installed after the scanner motor is assembled without any hindrance to the process, and it is possible to easily assemble required models and unnecessary models.

Further, when the surface of glass is touched with bare hands, fingerprints are attached, which is also one of the causes of defective drawing.
The structure is such that the holder is sandwiched and the thickness of the window portion of the holder 25 is selected so that even if the holder 25 is sandwiched and held, the bare surface does not touch the surface of the glass 26. So it's safe.

Since the cover 27 and the flange portion 18a are in flat contact with each other, the dust sealing condition is more than sufficient.
For laser beam printers that are heavily used,
It is possible to provide an inexpensive and highly productive dustproof cover that is easy to use with a cover or the like.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the overall structure.

FIG. 2 is an optical system unit box diagram.

FIG. 3 is a diagram showing stains on a polygon mirror.

FIG. 4 is an exploded perspective view of a scanner motor.

FIG. 5 is a sectional view of an optical path.

[Explanation of symbols]

18 ... Scanner motor, 19 ... Polygon mirror, 25
… Holder, 26… Glass, 27… Cover.

Claims (5)

[Claims] 1. A scanner motor having a polygon mirror for scanning a laser beam is provided with a general-purpose resin cover in order to prevent the polygon mirror from being contaminated, and an optical glass is placed in the optical path. This glass is made of a general-purpose resin. A laser beam printer, which is held by the holder and attached to the cover described above. 2. The laser beam printer according to claim 1, wherein the stain-proof covers such as glass are constructed as a motor having a polygon mirror and are detachable after the inspection is completed. 3. The holder for holding the glass is characterized by ensuring a thickness such that a finger or the like cannot be easily touched in order to prevent contamination of human contact oil when the glass is incorporated. Item 2. A laser beam printer according to item 1. 4. The laser beam printer according to claim 1, further comprising a cover having a substantially sealed structure for preventing outside air circulation due to positive and negative pressure generated by rotation of the polygon mirror. 5. The laser beam printer according to claim 1, wherein each component has an elastic structure that does not resonate due to vibration generated by rotation of the polygon mirror.