JP2000180776A - Optical scanner and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate heat radiation on the inside and the outside of an optical box by a cover which has good thermal conductivity. SOLUTION: A rotating polygon mirror 3 and an image-forming lens system 4 are incorporated in the optical box 10, and an aperture at the upper part of the optical box 10 is covered with a cover 20. The construction material of the cover 20 is material satisfactory in thermal conductivity, and the heat radiation on the inside and the outside of the optical box 10 is accelerated by covering the upper parts of a laser drive base plate 1c on the outside of the optical box 10 and a drive control board 11 which is the control part for the motor of the mirror 3 with the cover 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device used for an image forming apparatus such as a copying machine or a printer.

[0002]

FIG. 13 is a schematic view showing an image forming apparatus according to a conventional example.

The image forming apparatus A has a scanner section B serving as image reading means for reading image information on an image surface of a book document at an upper portion, and an image forming section C serving as image forming means at a lower portion. The sheet feeding device D is assembled below the sheet feeding device.

The scanner section B includes a scanning system light source 201,
The apparatus includes a platen glass 202, an original press 203 that can be opened and closed with respect to the apparatus main body 200, a mirror 204, a lens 205, a light receiving element (photoelectric conversion element) 206, an image processing unit, and the like. Then, a book document, a sheet document, or the like such as a book, thick paper, or curled paper is placed on the platen glass 202 with the document surface facing down. When the start key is pressed, the scanning system light source 201 scans the lower part of the platen glass 202 in the direction of arrow a to read image information on the document surface.

[0005] Image information of a document read by the scanning system light source 201 is processed by the image processing unit, is converted into an electric signal is transmitted to the optical scanning apparatus E _0. Here, the image forming apparatus A, the optical scanning apparatus E ₀ serves as a copier by forming an image by processing signals of the image processing unit, functions as a printer by forming an image by the output signal of the personal computer. Also, if an image is formed or a processing signal of the image processing unit is transmitted to a facsimile apparatus of another apparatus by a transmission signal from a facsimile apparatus of another apparatus, the apparatus functions as a facsimile apparatus.

On the other hand, a sheet feeding device D below the image forming section C is equipped with a sheet cassette 208. The sheet cassette 208 is composed of a lower cassette 208a and an upper cassette 208b, and one feeding unit. Is configured as Then, the sheets accommodated in the cassette are separated and fed one by one, and then conveyed by conveying rollers 212 and 213 which constitute conveying means, guided to registration rollers 214, and subjected to image formation by the registration rollers 214. The sheet is fed to the image forming section C in synchronization with the operation.

The image forming section C includes a photosensitive member 215, the optical scanning device E ₀ , a developing device 217, a transfer charger 218, and the like. Then, the light source 1 of the optical scanning device E ₀ is placed on the surface of the photoconductor 215 uniformly charged by the charger.
01 (see FIG. 14), a laser beam corresponding to the image information is scanned by a rotating polygon mirror 102 as a deflecting unit to form a latent image, and the latent image is formed on the latent image by a developing unit 217.
A toner image is formed on the sheet conveyed by the registration roller 214 in synchronization with the rotation of the photoconductor 215.
The transfer charger 218 transfers the toner image to the first surface of the sheet.

Reference numeral 219 denotes a conveyance belt for conveying the sheet on which the toner image is formed, 220 denotes a fixing device, and 221 denotes a discharge roller.

The sheet on which the toner image is formed is conveyed to the fixing device 220 by the conveyance belt 219 while being suctioned by the conveyance belt 219 by the sheet suction fan 210. Then, after being heated and pressed to fix the toner image on the sheet surface, the toner image is discharged and stacked by a discharge roller 221 on a tray 222 disposed outside the apparatus.

[0010] By such a series of processes, but to form an image on a sheet, a light source 101 of the optical scanning apparatus E ₀ described above causes heat by emission. In addition, the rotary polygon mirror 102, its motor 102a, and a drive control board 104 (see FIG. 14) for driving and controlling the motor are also provided.
Heat generation is caused by the rotation driving operation 02. The temperature rise due to such heat generation must be within a certain specification,
If the allowable value is exceeded, the operation and life of the device cannot be predicted.

As shown in FIG. 14, the rotating polygon mirror 102, the imaging lenses 103a and 103b, etc. are built in an optical box 110, and the upper opening of the optical box 110 is closed by a lid member 120. Motor 102a of rotating polygon mirror 102
As described above, the heat generated from the lid member 12 raises the temperature inside the optical box 110 and causes malfunction and shortens the life of the apparatus.
A heat radiating plate 121 for promoting heat radiation is brought into contact with the heat sink 0 to prevent the temperature inside the optical box 110 from rising.

[0012]

However, according to the above-mentioned prior art, a heat radiating plate or the like is brought into contact with a lid member for closing the upper opening of the optical box to prevent the temperature inside the optical box from rising. Etc. must be separately manufactured and assembled. Therefore, an increase in the number of parts and an increase in the complexity of the assembling process cannot be avoided.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and has a high performance by effectively avoiding a temperature rise due to heat generated by a driving unit or a light source of a rotary polygon mirror. An object of the present invention is to provide an optical scanning device and an image forming apparatus that have a long life and are low in cost.

[0014]

In order to achieve the above object, an optical scanning device according to the present invention comprises a light source for generating a light beam, a deflecting means for deflecting and scanning the light beam, and a driving means for driving the deflecting means. A driving unit, an imaging optical unit that forms an image of the light beam on the photoconductor via the deflection unit, an optical box that houses the imaging optical unit and the deflection unit, and a cover that closes an opening of the optical box. Wherein the cover is made of a material having good thermal conductivity, and also serves as a heat radiating member for promoting heat radiation of the light source and the driving means.

A light source for generating a light beam, a deflecting means for deflecting and scanning the light beam, a driving means for driving the deflecting means, and an image forming optical system for forming an image of the light beam on a photosensitive member via the deflecting means. Means, an optical box accommodating the imaging optical means and the deflecting means, and a cover for closing an opening of the optical box, wherein the cover is made of a material having good thermal conductivity, and The optical scanning device may further include a protruding portion that protrudes so as to cover the heat generating portion of the light source and the heat generating portion of the driving unit, which are disposed outside the box.

It is preferable that the projecting portion of the cover has a light source support for supporting the light source.

It is preferable that the projecting portion of the cover has a drive control board supporting portion for supporting the drive control board of the driving means.

Preferably, the cover is connected to a stay supporting the optical box.

[0019]

The cover for closing the opening of the optical box is made of a material having good heat conductivity, and also serves as a heat radiating member for efficiently discharging the heat generated from the drive section of the deflecting means in the optical box.

This cover not only closes the opening of the optical box, but also has a protruding portion for promoting heat radiation of the heat generating portion outside the optical box, thereby efficiently cooling the inside and outside of the optical box. That is, the projecting portions of the cover cover the heat generating portions such as the laser drive substrate of the light source disposed outside the optical box and the drive control board of the drive means, and promote the heat radiation of these.

Compared to a case where a heat sink or the like is manufactured and assembled separately from the cover, the number of assembly parts can be reduced, the assembly process can be simplified, and the manufacturing cost can be greatly reduced.

Further, by supporting the light source and the drive control board on the projecting shape portion of the cover, these supporting members are omitted, and it is possible to further contribute to reducing the number of assembly parts and simplifying the assembly process. In addition, by bringing the light source and the drive control board into contact with the cover, which is a heat dissipating member, the heat dissipating effect can be greatly improved.

Further, the optical box and the drive control board can be integrally attached to and detached from the image forming apparatus, and the efficiency of assembly and maintenance of the image forming apparatus can be improved.

Further, by connecting the cover to the stay supporting the optical box and releasing the heat of the cover to the stay, the heat radiation effect can be further improved.

[0025]

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

FIG. 1 shows an optical scanning device according to a first embodiment, in which a laser beam, which is a light beam generated from a semiconductor laser 1, is collimated by a collimator lens 1a and is linearly formed by a cylindrical lens 2. The light is condensed into a light beam and is incident on the reflection surface of the rotary polygon mirror 3 as the deflecting means. The reflected light is deflected and scanned by the rotation of the rotary polygon mirror 3 to become scanning light in a predetermined direction (main scanning direction). Image on the photoreceptor. The light beam that forms an image on the photoreceptor is mainly scanned by the rotation of the rotating polygon mirror 3, and
An electrostatic latent image is formed along with the sub-scan by the rotation of the rotating drum.

The semiconductor laser 1, the cylindrical lens 2, the rotary polygon mirror 3, the imaging lens system 4, and the like are mounted on the side and bottom walls of the optical box 10. The rotating drum is provided outside the optical box 10, and one end of the optical box 10 is provided with a window 10 a for extracting scanning light from the optical box 10.

The imaging lens system 4 comprises a spherical lens 4a and a toric lens 4b, and converts the scanning light scanned at a constant angular speed by the rotating polygon mirror 3 into a scanning light scanned at a constant speed on a rotating drum. Has functions.

The upward opening of the optical box 10 is
After the rotating polygon mirror 3 and the imaging lens system 4 and the like are assembled therein, the cover 20 is closed.

The motor 3a, which is a driving means for driving the rotary polygon mirror 3, is excited by a drive control board 11, which is a heat-generating portion disposed outside the optical box 10, and a drive current controlled by the drive control board 11. It has a magnetic circuit consisting of a stator and a rotor facing the stator.

The optical box 10 is fixed together with the drive control board 11 on a stay 30 provided in the apparatus main body of the image forming apparatus by a known method.

The semiconductor laser 1 is held by a laser holder 1b, is unitized by being integrally connected to the laser holder 1b and a lens barrel of a collimator lens 1a, and is a heating unit for emitting light from the semiconductor laser 1. A light source is constituted together with the drive board 1c.

During the operation of the optical scanning device, the inside of the optical box 10 is heated by the heat generated from the motor 3a of the rotary polygon mirror 3, and the light source including the semiconductor laser 1 and the laser driving substrate 1c and the motor 3a The atmosphere outside the optical box 10 is also heated by the heat generated from the drive control board 11, which is a control unit. For this reason, the imaging lens system 4 in the optical box 10
The temperature rise of the optical parts such as the above is remarkable, and there is a problem such as a malfunction or a short life due to the deterioration of the optical performance.

Therefore, in order to quickly release the heat generated inside and outside the optical box 10 and avoid deterioration of the optical performance due to the temperature rise, the cover 20 covering the optical box 10 is thermally conductive. The plate 20 is made of a material having good properties, for example, a non-ferrous metal such as aluminum, and the outer shape of the cover 20 is enlarged.
A protruding portion is provided not only to cover the upper opening of the optical box 10 but also to cover a heating portion such as the drive control board 11 and the laser drive substrate 1c disposed outside the optical box 10 (in FIG. 3, a solid line). Shown).

That is, the cover 20 functions as a heat radiating member for releasing heat generated from the motor 3a and the like in the optical box 10 and the drive control board 11 outside the optical box 10
, Which has a function as a heat radiating member for releasing heat generated from the laser drive substrate 1c and the like, and furthermore, a dust proof for preventing external dust and the like from entering the optical box 10; It also has an original cover function such as soundproofing for preventing noise such as wind noise and motor noise from leaking to the outside.

As described above, the projection for covering the heat generating portion outside the optical box is provided on the dust-proof and sound-proof cover, so that it can be multifunctionally used as a heat radiating member for promoting heat radiation inside and outside the optical box. The number of parts of the apparatus can be greatly reduced and the assembling process can be simplified as compared with the case where a heat sink is provided separately from the lid member as in the conventional example.

As a result, it is possible to greatly contribute to higher performance and lower cost of the optical scanning device and the image forming apparatus equipped with the same.

FIG. 4 shows a modification. In this embodiment, a heat radiating fin 41 is provided on a cover 40 similar to the cover 20 of FIG. It is needless to say that the radiation fins 41 are shaped so that the air flow smoothly flows, as shown in FIG. The heat radiation fins 41 increase the contact area with the atmosphere, and the heat radiation effect is further improved.

The radiation fins may be formed integrally when the cover is manufactured.

FIG. 6 shows a second embodiment. this is,
A support 5 which is a light source support for supporting the light source unit including the semiconductor laser 1 and the collimator lens 1a on the cover 50
1 are provided integrally. The light source including the semiconductor laser 1 and the laser driving substrate 1c generates heat itself. Since the light source and the cover 50 are always in contact, the heat radiation effect of the light source is much better than in the first embodiment.

The semiconductor laser 1, the collimator lens 1a,
Since the laser drive substrate 1c, the optical box 10, and the like are the same as those in the first embodiment, they are denoted by the same reference numerals, and description thereof is omitted.

FIG. 7 shows a third embodiment. this is,
The cover 61 covers a support 61 which is a drive control board supporting portion for supporting the drive control board 11 of the motor 3a of the rotary polygon mirror 3.
It is provided on the zero protruding portion. Since the cover 60 is in contact with the drive control board 11, the drive control board 1
1 is more efficiently dissipated. The support 61 of the cover 60 is used as a support surface of the drive control board 11 by bending the end of the cover 60 to near the bottom wall of the optical box 10.

In this configuration, the thickness of the entire optical scanning device is taken into consideration. However, as shown in FIG. 8, the drive control board 11 may be mounted upside down without bending the cover 60. In this case, since the cover 60 remains a flat plate, there is an advantage that the processing cost can be reduced.

Alternatively, as shown in FIG. 9, a suspension-shaped portion 62 suspended by the cover 60 may be provided so as to surround the drive control board 11. Since the drive control board 11 is in contact with the cover 60 and is surrounded by the suspension-shaped portion 62 of the cover 60, the heat radiation effect is further improved.

Rotating polygon mirror 3, motor 3a, optical box 10,
Since the drive control board 11 and the like are the same as those in the first embodiment, they are denoted by the same reference numerals and description thereof is omitted.

FIGS. 10 and 11 show a fourth embodiment. In this configuration, the cover 70 is in contact with a stay 80 provided on the apparatus main body of the image forming apparatus, and is connected by screws 81. Since the heat energy absorbed by the cover 70 can be transmitted to the apparatus main body of the image forming apparatus, the heat radiation effect is further improved. The stay 80 is preferably made of a non-ferrous metal or the like having good thermal conductivity, but is not limited to this.

FIG. 11 is an enlarged view of the connecting portion by the screw 81 of FIG.

Below the stay 80, an image forming section of the image forming apparatus is provided. This is composed of a rotating drum 91 holding a photoreceptor on the surface, a developing device 92, a transfer charger 93 and the like. The laser beam scanned by the rotating polygon mirror 3 forms a latent image on the charged photoreceptor, and a toner image is formed on the latent image by the developing device 92, and the registration roller 94 synchronizes with the rotation of the rotating drum 91. The toner image is transferred onto the first surface of the sheet by the transfer charger 93 on the conveyed sheet.

Reference numeral 95 denotes a transport belt for transporting a sheet on which toner is formed, reference numeral 96 denotes a fixing device, and reference numeral 97 denotes a discharge roller. The sheet on which the toner image has been formed is conveyed to a fixing device 96 by a conveying belt 95 and heated and pressed to fix the toner image on the sheet surface.
7, the sheet is discharged and loaded on a sorter arranged outside the machine.

FIG. 12 shows a modification of the fourth embodiment. This is one in which a cushion member 82 is interposed between the cover 70 and the stay 80. When the cover 70 and the stay 80 are directly fastened, a slight gap is generated in a microscopic view. Therefore, in order to transmit heat more efficiently, a member having a certain degree of elasticity and good thermal conductivity,
For example, silicon rubber is interposed as the cushion member 82.

When the cover 70 is provided with a light source support similarly to the apparatus shown in FIG. 6, if the semiconductor laser of the light source is of a type that applies a voltage to the package side, the cover 7
Voltage will also be applied to the entire zero. In such a case, if the stay 80 is an iron plate, it is very effective to interpose insulating silicon rubber or the like since the stay 80 may be grounded and the light source may be broken.

[0052]

Since the present invention is configured as described above, it has the following effects.

The temperature rise of the optical scanning device can be avoided very efficiently without using a separate component such as a heat sink. As a result, it is possible to realize an optical scanning device and an image forming apparatus that have high performance and long life and that are low in manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an optical scanning device according to a first embodiment.

FIG. 2 is a sectional view showing the apparatus of FIG. 1;

FIG. 3 is a plan view showing a cover of the apparatus of FIG. 1;

FIG. 4 is a cross-sectional view showing a modification of the first embodiment.

FIG. 5 is a plan view showing a cover of the apparatus of FIG. 4;

FIG. 6 is a partial cross-sectional view illustrating a main part of an optical scanning device according to a second embodiment.

FIG. 7 is a sectional view showing an optical scanning device according to a third embodiment.

FIG. 8 is a cross-sectional view illustrating a first modification of the third embodiment.

FIG. 9 is a cross-sectional view illustrating a second modification of the third embodiment.

FIG. 10 is a schematic diagram showing a fourth embodiment.

11 is a partially enlarged view showing a part of the apparatus of FIG. 10 in an enlarged manner.

FIG. 12 is a partial sectional view showing a modification of the fourth embodiment.

FIG. 13 is a schematic diagram illustrating an image forming apparatus according to a conventional example.

FIG. 14 is a partial plan view showing only the optical scanning device of FIG. 13;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 1a Collimator lens 1c Laser drive board 2 Cylindrical lens 3 Rotating polygon mirror 4 Imaging lens system 5 Folding mirror 10 Optical box 11 Drive control board 20, 40, 50, 60, 70 Cover 30, 80 Stay 41 Radiation fin 51 , 61 support body 62 suspension shape part 81 screw 82 cushion member

Claims (6)

[Claims] A light source for generating a light beam; a deflecting means for deflecting and scanning the light beam; a driving means for driving the deflecting means; and an image forming means for forming an image of the light beam on a photosensitive member via the deflecting means. An optical box containing the imaging optical unit, the imaging optical unit and the deflecting unit, and a cover closing an opening of the optical box, wherein the cover is made of a material having good thermal conductivity, and And an optical scanning device, which also serves as a heat radiating member for promoting heat radiation of the driving means. A light source for generating a light beam; a deflecting means for deflecting and scanning the light beam; a driving means for driving the deflecting means; An image optical unit, an optical box that houses the image forming optical unit and the deflecting unit, and a cover that closes an opening of the optical box; the cover is made of a material having good thermal conductivity; and An optical scanning device, comprising: a protruding portion that protrudes so as to cover a heat generating portion of the light source and a heat generating portion of the driving means disposed outside the optical box. 3. The projection of the cover has a light source support for supporting a light source.
The optical scanning device according to claim 1. 4. The optical scanning device according to claim 1, wherein the projecting portion of the cover has a drive control board supporting portion for supporting a drive control board of the driving means. 5. The optical scanning device according to claim 1, wherein the cover is connected to a stay supporting the optical box. 6. An image forming apparatus comprising: the optical scanning device according to claim 1; a rotating drum configured to rotate a photosensitive member; and an apparatus main body including the rotating drum and the optical scanning device.