JP2001142023A - Laser scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laser scanner with improved heat radiating properties. SOLUTION: An optical box 50 is constituted of aluminum having high heat conductivity, and a motor 52 to which a polygon mirror 51 is attached is arranged inside the box 50. A cylindrical part 53a is provided on the flange 53 of the motor 52 so as to surround the lower part of the mirror 51 for the purpose of rectification. The periphery of the mirror 51 in the box 50 is covered with a cover member 54 consisting of aluminum for the purpose of tight sealing, and a cylindrical part 54a for rectification is provided inside the member 54. An aperture part 54b through which a laser beam is inputted/outputted is provided on the external wall of the member 54. In order to improve tight sealing properties, a sealing member 56 consisting of heat radiation rubber and having high heat conductivity is interposed between the box 50 and the member 54, and a sealing member 57 consisting of an O-ring for improving the tight sealing properties and having the high heat conductivity is interposed between the housing 50 and the motor 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art FIG. 3 is a partial sectional view of a laser scanning apparatus used in a conventional digital color copying machine or the like. The polygon motor unit is disposed inside the optical box 1, and the cover 2 prevents dust and the like from entering from outside. Inside the housing 4 of the motor 3, a polygon mirror 5 attached to a rotating part (rotor) of the motor 3 is arranged. O-ring 6 between motor 3 and optical box 1
a is interposed to enhance the airtightness.

The inner wall of the housing 4 has a cylindrical shape with an opening at the top to provide a rectifying effect, and an opening 4a for inputting / outputting laser light is provided on a side surface of the cylindrical portion. Is sealed by glass 7 from the outside of the housing 4. A cover member 8 is fitted on the housing 4, and an O-ring 6 b is interposed between the cover member 8 and the cylindrical portion of the housing 4 to improve the hermeticity of the housing 4 and the cover member 8. I have. Further, a lower portion of the motor 3 is projected outside the optical box 1 for heat radiation, and a radiation fin 10 is further provided.

In such a configuration, when the polygon mirror 5 is driven to rotate by the motor 3 and scans the laser beam toward the photosensitive drum, the number of rotations per second of the motor 3 is N (s ^-1 ). Is N = V × R / (2) where M is the number of surfaces of the polygon mirror 5, V is the transport speed in the sub-scanning direction, and R is the resolution in the sub-scanning direction.
(5.4 × M).

[0005] As the performance of the copying machine is improved, the transport speed and the resolution are improved, and accordingly, the rotation speed N of the motor 3 is also increased. When the number of revolutions N of the motor 3 increases, the noise of the rotation of the motor 3 and the wind noise of the polygon mirror 5 increase, causing a problem as noise. Also occurs.

As described above, the polygon mirror 5
In general, noise is prevented from leaking to the outside by sealing the periphery of the optical box, the rigidity of the optical box 1 is improved, and the vibration of the polygon mirror 5 serving as a sound source is hardly transmitted to the outside. In addition, as a countermeasure against heat generation, a radiating fin 10 is added to the motor 3 or a cover for rectification is provided around the polygon mirror 5 to reduce windage loss.

By taking such noise countermeasures, the noise is reduced, and the housing 4 of the motor 3 and the radiation fins 1
By changing the materials of the cover member 8 and the optical box 1 to aluminum having high thermal conductivity, heat generation can be reduced. In addition, heat radiation can be further improved by blowing air to the radiation fins 10 as necessary.

[0008]

However, in the above-mentioned conventional example, the polygon mirror 5 is used to reduce noise.
If the surrounding area is closed, the heat generated by the windage becomes difficult to be released. Of the heat generated by the windage of the polygon mirror 5, etc.,
The heat transferred to the cover member 8 is transferred to the motor 3
Otherwise, heat cannot be transferred to the radiation fins 10 and the optical box 1, and the heat radiation of the polygon mirror 5 becomes insufficient.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a laser scanning device in which the heat dissipation of a closed polygon mirror is improved.

[0010]

According to the present invention, there is provided a laser scanning apparatus having an optical box having a built-in polygon mirror connected to a motor, wherein the cover member covers the polygon mirror. A first seal member that seals the optical box and the motor, and a second seal member that seals the optical box and the cover member, wherein the optical box and the cover member have thermal conductivity. It is characterized by being made of a high material, and at least one of the first seal member and the second seal member is made of an elastic body having a high thermal conductivity.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a cross-sectional view of a digital color copying machine. The digital color copying machine has a digital color image reader section at the top and a digital color image printer section at the bottom. And is exposed and scanned by an exposure lamp 12 so that a reflected light image from the original S is
, And is condensed on the full-color sensor 14 to obtain a color-separated image signal. The color-separated image signal is processed by an amplifying circuit and a video processing unit (not shown) and then sent to a digital color image printer.

The digital color image printer section includes a photosensitive drum 15, a pre-exposure lamp 16 disposed around the photosensitive drum 15, a corona charger 17, and a laser scanning device 1.
8, potential sensor 19, four developing units 20y of different colors
(Yellow), 20c (cyan), 20m (magenta), 20b (black), light amount detecting means 21 provided on drum 15, transfer device 22, cleaning device 23
It is composed of

An image signal from the digital color image reader unit is converted into an optical signal at a laser output unit (not shown), and the converted optical signal is reflected by a polygon mirror 18a in a laser scanning device 18, and is converted into a light signal.
The light is projected onto the photosensitive drum 15 via the mirror b and the mirror 18c. During image formation, the photosensitive drum 15, which is a rotatably supported image carrier, is rotated in the direction of the arrow, and after the charge is removed by using the pre-exposure lamp 16, the photosensitive drum 15 is removed by using the corona charger 17. And a latent image is formed by irradiating each of the separated colors with a light image.

Next, predetermined developing units 20y, 20c, 20
By operating m and 20b, the latent image on the photosensitive drum 15 is developed, and a toner image based on resin is formed on the photosensitive drum 15. Subsequently, the developing devices 20y, 20c, 20m, 2
0b selectively approaches the photosensitive drum 15 in accordance with each separation color by the operation of the eccentric cams 24y, 24c, 24m, 24b.

Further, the toner image formed on the photosensitive drum 15 is transferred by a sheet cassette 25 to a sheet supplied to a position facing the photosensitive drum 15 via a transfer system and a transfer device 22. The transfer device 22 includes a transfer drum 22a, a transfer charger 22b, and an attraction roller 22 that is opposed to an attraction charger 22c for electrostatically attracting a sheet.
d, an inner charger 22e and an outer charger 22f, and a transfer sheet 22g made of a dielectric material such as a polycarbonate film is formed in a cylindrical shape in a peripheral opening area of a transfer drum 22a which is rotatably supported so as to be cylindrical. It is stretched integrally on top.
In this way, a desired number of color images are transferred to the sheet suction-conveyed to the carrier sheet 22g, and a full-color image is formed.

When the transfer of the four color toner images is completed, the sheet is separated from the transfer drum 22a by the separation claws 26,
The sheet is separated by the action of the separation push-up roller 27 and the separation charger 28, and is discharged to the tray 30 via the heat roller fixing device 29. On the other hand, after the image is transferred to the sheet, the photosensitive drum 15
After the residual toner remaining on the surface is cleaned by the cleaning device 23, the toner is again supplied to the image forming step.

When images are formed on both sides of a sheet, the sheet is ejected from the heat roller fixing device 29, and then the conveyance path switching guide 31 is driven immediately.
After being guided to the reversing path 33 once, the reversing roller 34 is rotated in the reverse direction so that the reversing roller 34 is retracted in a direction opposite to the direction in which the paper is fed, with the rear end of the paper being fed, and stored in the intermediate tray 35. Thereafter, an image is formed on the other surface by passing through the image forming step again.

Further, a fur brush 36 and a backup brush 37 are provided so as to be opposed to the carrier sheet 22g in order to prevent the powder from being scattered and adhered on the carrier sheet 12g, and to prevent oil from adhering to the sheet. Therefore, the oil removing roller 3 is set so as to face the carrier sheet 22g.
8. Cleaning is performed by providing a backup brush 39. Such cleaning is performed before or after image formation, and is performed as needed when a jam, that is, a paper jam occurs.

The gap between the carrier sheet 22g and the photosensitive drum 15 can be arbitrarily set by operating the eccentric cam 40 at a desired timing and operating the cam follower 41 integrated with the transfer drum 22a. For example, the interval between the transfer drum 22a and the photosensitive drum 15 can be increased during standby or when the power is turned off.

FIG. 2 is a sectional view of the laser scanning device 18 according to the present embodiment. The housing 50 is made of aluminum having a high thermal conductivity, and a polygon mirror 51 is provided inside the optical box 50. Mirror 51
Is attached to a rotor of a motor 52 arranged inside the optical box 50. Flange 53 above motor 52
Is provided with a cylindrical portion 53a so as to surround a lower portion of the polygon mirror 51 for rectification. The optical box 50
A cover member 54 made of aluminum for sealing is covered around the polygon mirror 51 inside, and a cylindrical portion 54 facing downward for rectification is provided inside the cover member 54.
a is provided, and an opening 54b through which laser light is input / output is provided on the outer wall 54 of the cover member. Outside the opening 54b, a glass 55 for sealing the opening 54b is provided. Further, a sealing member 56 made of a heat radiation rubber having a high thermal conductivity is interposed between the optical box 50 and the cover member 54 to improve the sealing property, and the sealing property between the optical box 50 and the motor 52 is improved. A sealing member 57 made of an O-ring and having a high thermal conductivity is interposed. Further, a lower portion of the motor 52 is projected outside the optical box 50, and a radiating fin 58 for further improving the heat radiation is provided.

Outside the opening 54b of the cover member 54, optical systems 59 and 60 for forming a laser beam emitted from a light source and scanned by the polygon mirror 51 on the photosensitive drum 15 are provided. Further, the optical box 50
Is sealed by a lid 61, and a laser circuit board 62 is arranged on the upper part of the lid 61.

In the laser scanning device 18 having the optical box 50 configured as described above, the noise generated by the polygon mirror 51 is cut off by the cover member 54 and the motor 52
Is generated from the optical box 50 through the radiation fins 58 or directly or through the seal member 57, and the heat generated in the polygon mirror 51 is released from the optical box 50 through the cover member 54 and the seal member 56. . In this case, even if one of the seal members 56 and 57 is a normal seal member having a low thermal conductivity, there is a certain effect.

[0023]

As described above, in the laser scanning device according to the present invention, since the heat generated by the polygon mirror and the heat generated by the motor can be transmitted to the optical box independently and released, the polygon mirror can be used. Temperature rise can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a digital color copying machine.

FIG. 2 is a cross-sectional view of the optical box in the present embodiment.

FIG. 3 is a sectional view of a conventional optical box.

[Explanation of symbols]

 Reference Signs List 18 laser scanning device 50 optical box 51 polygon mirror 54 cover member 55 glass 56, 57 seal member 58 heat radiation fin 59, 60 optical system 61 lid portion 62 circuit board

Claims (3)

[Claims] 1. A laser scanning apparatus having an optical box having a built-in polygon mirror connected to a motor, a cover member for covering the polygon mirror, a first seal member for sealing the optical box and the motor, and A box and a second seal member for sealing the cover member, wherein the optical box and the cover member are made of a material having high thermal conductivity, and at least one of the first seal member and the second seal member. One is a laser scanning device, which is made of an elastic material having high thermal conductivity. 2. The laser scanning device according to claim 1, wherein said optical box and said cover member are made of aluminum. 3. The laser scanning device according to claim 1, wherein said elastic body is rubber.