JP3619665B2 - Deflection scanner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a deflection scanning apparatus that is used in a digital copying machine, a laser facsimile, a laser printer, a laser plotter, and the like and deflects and scans a light beam.
[0002]
[Prior art]
A deflection scanning device that deflects and scans a light beam with a rotary polygon mirror is used for a laser printer or the like. The deflection scanning device includes a rotating polygon mirror that deflects and scans a light beam, a rotating polygon mirror driving motor device that rotationally drives the rotating polygon mirror, and a motor device driving motor that drives the rotating polygon mirror driving motor device. And an optical box containing a rotating polygon mirror, a rotating polygon mirror driving motor device, a motor device driving IC, and the like.
[0003]
In recent years, demands for higher speed and higher definition are increasing in laser printers and the like. In order to achieve high speed and high definition in a laser printer or the like, it is necessary to rotate the rotary polygon mirror driving motor device at high speed. In addition, due to intensifying cost competition in recent years, many of the above optical boxes are made of plastic instead of metal, but a cover is used to suppress wind noise and dirt such as dust on the rotating polygon mirror. In many cases, the space around the rotating polygonal mirror is almost sealed.
Japanese Unexamined Patent Publication No. Hei 6-230306 has a rotary polygon mirror that deflects a light beam emitted from a light beam generating means, and a motor device that rotationally drives the rotary polygon mirror, and a driving IC for the motor device. The deflection scanning device is provided with a heat absorption member such as aluminum having a large heat capacity and / or thermal conductivity on the back surface of the mounting portion of the driving IC of the metal substrate. Has been described.
[0004]
[Problems to be solved by the invention]
In the deflection scanning device, the space around the rotary polygon mirror is made substantially sealed using the cover, so that heat is trapped inside the optical box, and heat is generated by the motor device driving IC and the bearing portion of the rotary polygon mirror. The temperature around the rotating polygon mirror may increase significantly, and the life of the rotating polygon mirror may decrease. Further, if measures such as providing a fan for such a problem are taken, the cost becomes very high.
[0005]
In the deflection scanning apparatus described in the above-mentioned Japanese Patent Application Laid-Open No. 6-230306, since a heat absorbing member such as aluminum having a large heat capacity and / or thermal conductivity is provided, the cost increases. Further, when the metal heat absorbing member is elastically pressed against the back surface of the metal substrate (usually a steel plate) of the motor device, there is a possibility that the metal substrate is deformed and that the rotating shaft of the rotary polygon mirror is tilted.
[0006]
In order to prevent this, it is conceivable to sandwich a member having a cushioning property and high thermal conductivity between the metal heat absorbing member and the metal substrate of the motor device. However, since the thermal resistance increases as the thickness of the member sandwiched between the metal heat-absorbing member and the metal substrate of the motor device increases in this way, in order to increase the heat absorption efficiency, It is necessary to make the member sandwiched between the heat absorbing member and the metal substrate of the motor device as thin as possible.
[0007]
However, the thinner the member sandwiched between the metal heat absorbing member and the metal substrate of the motor device, the lower the effect as a cushion, and the metal substrate of the motor device may be deformed by the rigidity of the heat absorbing member. In order not to apply an excessive force to the metal substrate of the motor device, it becomes necessary to strictly control the distance (dimensional tolerance) between the metal heat absorbing member and the metal substrate of the motor device. As a result, the material and thickness of the member sandwiched between the metal heat absorbing member and the metal substrate of the motor device must be balanced with the positional accuracy of the heat absorbing member with respect to the metal substrate of the motor device, which is extremely limited. Big and costly.
[0008]
In general, when a metal member is present in a state where it is not electrically grounded in the apparatus, it may be discharged at once when it is charged with static electricity and may cause damage to an electric circuit or the like.
An object of the present invention is to provide a deflection scanning apparatus that can reduce the temperature rise around the rotary polygon mirror and prevent the life of the rotary polygon mirror from being reduced.
[0009]
An object of the present invention is to provide a deflection scanning device capable of preventing static electricity from accumulating on a first heat absorbing member made of metal.
The invention according to claim 2 is to provide a deflection scanning device that can reduce the temperature rise around the rotary polygon mirror at low cost and prevent the life of the rotary polygon mirror from being reduced .
[0010]
Another object of the present invention is to provide a deflection scanning device that can further enhance the effect of heat absorption.
It is another object of the present invention to provide a deflection scanning apparatus that can provide one heat radiating portion outside the optical box and can obtain the effects of the deflection scanning apparatus according to claim 3 at a low cost. And
[0011]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 includes a rotary polygon mirror that deflects and scans a light beam from a light source, and a motor device that rotationally drives the rotary polygon mirror. In the deflection scanning apparatus provided above, a first heat absorbing member made of metal that is provided with a predetermined gap from the back surface of the metal substrate and that partially dissipates heat , the metal substrate, and the first heat absorbing member. A member having a high conductivity provided between the member and electrically connecting the metal substrate and the first heat-absorbing member, wherein the metal substrate is grounded .
[0012]
According to a second aspect of the present invention, in the deflection scanning apparatus according to the first aspect, the first heat absorbing member is made of a steel plate.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a first embodiment of the present invention. The first embodiment is an embodiment of a deflection scanning device of an image forming apparatus such as a laser printer, and is used for driving a motor device that constitutes a rotary polygon mirror 2, a motor device 3, and a motor device driving unit in an optical box 1. An IC 4 and a metal substrate 5 for a magnetic circuit are accommodated. A cover 6 is attached to the optical box 1 so that the inside of the optical box 1 is substantially sealed, and the metal substrate 5 is fixed to the optical box 1. The rotation shaft of the rotor 3a in the motor device 3 is rotatably supported by the optical box 1 with a bearing or the like, and the stator 3b of the motor device 3 is fixed to the metal substrate 5 so as to face the rotor 3a.
[0017]
A flange 7 is fixed to the rotation shaft of the rotor 3a, and the rotary polygon mirror 2 is fixed on the flange 7 concentrically with the rotation shaft of the rotor 3a. The rotor 3 a is fixed to the lower surface of the flange 7, and the motor device driving IC 4 is fixed to the metal substrate 5. Moreover, the heat absorption / radiation member 8 is made of, for example, a steel plate, and includes a heat absorption part 8a and a heat radiation part 8b. The heat absorbing portion 8a is disposed between the lower surface of the metal substrate 5 and the bottom surface of the optical box 1, and a predetermined gap is provided between the heat absorbing portion 8a and the lower surface of the metal substrate 5, so that the heat absorbing portion 8a and the optical box 1 A predetermined gap is provided between the bottom surface. The heat absorption / radiation member 8 is fixed to the optical box 1, and the heat radiation portion 8 a of the heat absorption / radiation member 8 is provided outside the optical box 1.
[0018]
The motor device 3 is driven by a motor device driving IC 4 to rotationally drive the rotary polygon mirror 2, and the deflection scanning device of the first embodiment is used in an image forming apparatus such as a laser printer so that laser light from a laser light source is emitted. Deflection scanning is performed by the rotary polygon mirror 2. The laser beam from the rotary polygon mirror 2 is condensed by a lens group and scans on the photoreceptor. Heat generated in the motor device driving IC 4 and the receiving portion of the rotary polygon mirror 2 is transmitted through the metal substrate 5 to the heat absorbing / dissipating member 8, and is released from the heat absorbing / dissipating member 8 a of the heat absorbing / dissipating member 8 outside the optical box 1. The Since the heat absorbing / dissipating member 8 is not in contact with the metal substrate 5, the metal substrate 5 is not deformed by the rigidity of the heat absorbing / dissipating member 8.
[0019]
The first embodiment includes a rotary polygon mirror 2 that deflects and scans a light beam from a light source (laser light from a laser light source), and a motor device 3 that rotationally drives the rotary polygon mirror 2. In the deflection scanning apparatus equipped with 3 on the metal substrate 5, heat absorption / radiation as a first heat absorption member made of metal which is provided with a predetermined gap from the back surface of the metal substrate 5 and partly radiates heat. Since the member 8 is provided, the temperature rise around the rotating polygon mirror can be reduced without causing the first heat absorbing member to touch the metal substrate and deform by applying extra force, and the life of the rotating polygon mirror is reduced. Can be prevented.
[0020]
In the first embodiment , since the first heat absorbing member 8 is made of a steel plate, the temperature increase around the rotary polygon mirror can be reduced at a low cost, and the life of the rotary polygon mirror can be prevented from being reduced. .
[0021]
In general, a polygon scanner in which a metal substrate of a motor device is a steel plate is often used. The first embodiment uses a steel plate that is the same as the metal substrate instead of using a heat absorbing member having a large heat capacity and / or thermal conductivity as in the deflection scanning device described in JP-A-6-230306. An endothermic effect is obtained.
[0022]
FIG. 2 shows a second embodiment of the present invention. In the second embodiment, a highly conductive member 9 is provided between the metal substrate 5 and the heat absorbing / dissipating member 8 in the first embodiment. The highly conductive member 9 is a leaf spring made of a phosphor bronze plate, and is elastically interposed between the metal substrate 5 and the heat absorbing / dissipating member 8. The heat absorbing / dissipating member 8 is electrically connected to the highly conductive member 9, and the metal substrate 5 is grounded via a harness (not shown). Therefore, the heat absorbing / dissipating member 8 is discharged to the ground side through the highly conductive member 9, the metal substrate 5, and the harness, and static electricity does not accumulate.
[0023]
This second embodiment is an embodiment of the invention according to claim 1, in the first embodiment, is provided between the heat absorbing-radiating member 8 as the first heat absorbing member and the metal substrate 5 Since the high-conductivity member 9 that electrically connects the metal substrate 5 and the first heat absorbing member 8 is provided, the same effect as the deflection scanning apparatus according to claim 1 can be obtained. In addition, static electricity can be prevented from being accumulated in the first heat absorbing member made of metal.
[0024]
FIG. 3 shows a third embodiment of the present invention. In the third embodiment, the heat absorbing portion 10a of the heat absorbing / dissipating member 10 is arranged on the motor device driving IC 4 with a predetermined gap in the first embodiment, and the heat dissipating portion of the heat absorbing / dissipating member 10 is arranged. 10 b is provided outside the optical box 1. The heat generated in the motor device driving IC 4 and the rotary polygon mirror 2 receiving part is transmitted through the metal substrate 5 to the heat absorbing / dissipating member 8 and released from the heat absorbing / dissipating part 8 a of the heat absorbing / dissipating member 8 outside the optical box 1. The heat generated in the motor device driving IC 4 (the most heat generating source around the rotary polygon mirror), which is one of the heat generating sources, is transmitted to the heat absorbing / dissipating member 10 and the heat absorbing / dissipating member 10 outside the optical box 1. Released from the heat radiating portion 10a. Since the IC package (IC 4 for driving the motor device) provided on the surface of the metal substrate 5 and the heat absorbing / dissipating member 10 are not in contact with each other, the IC package is pushed by the rigidity of the heat absorbing / dissipating member 10 and the metal substrate 5 Is prevented from deforming.
[0025]
In the third embodiment, in the first embodiment , a motor device driving IC 4 for driving the motor device 3 provided on the metal substrate 5, and a predetermined amount on the motor device driving IC 4. Since the heat absorption / radiation member 10 as the second heat absorption member provided with a gap is provided, the effect of heat absorption can be further enhanced.
[0026]
FIG. 4 shows a fourth embodiment of the present invention. In the fourth embodiment, in the first embodiment, one end portion of the heat absorbing member 11 is disposed on the motor device driving IC 4 with a predetermined gap, and the other end portion of the heat absorbing member 11 is configured to absorb heat and dissipate heat. It is fixed in contact with the member 8. The heat generated by the motor device driving IC 4 is transmitted through the heat absorbing member 11 and the heat absorbing / dissipating member 8 and released from the heat radiating portion 8 a of the heat absorbing / dissipating member 8 outside the optical box 1.
[0027]
In the fourth embodiment, in the first embodiment, since the heat absorbing member 11 as the second heat absorbing member is in contact with the heat absorbing-radiating member 8 as the first heat absorbing member, outside the optical box The number of heat dissipating sections can be reduced to one, and the effect of the deflection scanning device according to claim 4 can be obtained at low cost.
[0028]
Next, the temperature measurement results of the fifth embodiment a, sixth embodiment b, seventh embodiment c, and eighth embodiment d of the present invention will be described. FIG. 5 shows a fifth embodiment a. In the fifth embodiment a, a double-sided pressure-sensitive adhesive sheet 12 as a highly conductive member is provided between the metal substrate 5 and the heat absorbing / dissipating member 8 in the first embodiment. 12 are attached to the metal substrate 5 and the heat absorbing / dissipating member 8. The thickness of the heat absorbing / dissipating member 8 is 1.6 mm.
[0029]
The double-sided pressure-sensitive adhesive sheet 12 is a double-sided conductive tape X-7001 (copper-plated cloth) manufactured by Sumitomo 3M, and has a thickness of 0.1 mm. The double-sided pressure-sensitive adhesive sheet 12 has high conductivity and high thermal conductivity. Since the double-sided pressure-sensitive adhesive sheet 12 does not float electrically, high thermal conductivity is obtained while taking electrical conduction with the metal substrate 5. The heat absorbing / dissipating member 8 is made of aluminum.
In the sixth embodiment b, in the fifth embodiment a, the heat absorbing / dissipating member 8 is made of a steel plate.
[0030]
FIG. 6 shows a seventh embodiment c. In the seventh embodiment c, the double-sided pressure-sensitive adhesive sheet 12 as a highly conductive member is provided between the metal substrate 5 and the heat absorbing / dissipating member 8 in the fourth embodiment. 12 are attached to the metal substrate 5 and the heat absorbing / dissipating member 8. The heat absorbing / dissipating member 8 is made of a steel plate. The thickness of the heat absorption / radiation member 8 and the heat absorption member 11 is 1.6 mm. The heat absorbing member 11 is made of aluminum and has a thickness of 2 mm.
[0031]
FIG. 7 shows an eighth embodiment d. In the eighth embodiment d, in the fourth embodiment, the heat absorption / radiation member 8 is made of a steel plate, and a gap of about 0.4 mm is provided between the heat absorption member 11 and the metal substrate 5. The thickness of the heat absorption / radiation member 8 and the heat absorption member 11 is 1.6 mm. The heat absorbing member 11 is made of aluminum and has a thickness of 2 mm.
[0032]
FIG. 8 shows the temperature measurement results of the fifth embodiment a, the sixth embodiment b, the seventh embodiment c, and the eighth embodiment d. From this measurement result, the effect of reducing the temperature rise around the rotary polygon mirror is the same regardless of whether the heat absorbing / dissipating member 8 is made of aluminum or steel plate, and between the metal substrate 5 and the heat absorbing / dissipating member 8. Even if the double-sided pressure-sensitive adhesive sheet 12 as a highly conductive member is provided, or even if a gap is provided between the metal substrate 5 and the heat absorbing / dissipating member 8, the effect of reducing the temperature rise around the rotary polygon mirror is the same. I understand.
[0033]
【The invention's effect】
As described above, according to the first aspect of the present invention, the above configuration reduces the temperature rise around the rotary polygon mirror without causing the first heat absorbing member to be shaken by the metal substrate and applying an extra force to deform it. It is possible not only to prevent the life of the rotating polygon mirror from being reduced , but also to prevent static electricity from accumulating on the first heat absorbing member made of metal.
[0034]
According to the invention which concerns on Claim 2, the said structure WHEREIN: The temperature rise around a rotary polygon mirror can be reduced at low cost, and the lifetime reduction of a rotary polygon mirror can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a second embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a third embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a fourth embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a fifth embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a sixth embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a seventh embodiment of the present invention.
FIG. 8 is a diagram showing the temperature measurement results of the fifth to eighth embodiments.
[Explanation of symbols]
2 Rotating polygon mirror 3 Motor device 4 Motor device driving IC
5 Metal substrate 8 Heat absorption / radiation member 9 High conductivity member 10 Heat absorption / radiation member 11 Heat absorption member

Claims (2)

In a deflection scanning device having a rotary polygon mirror that deflects and scans a light beam from a light source and a motor device that rotationally drives the rotary polygon mirror, and the motor device is mounted on a metal substrate.
A first heat-absorbing member made of a metal which is provided with a predetermined gap from the back surface of the metal substrate and a part of which radiates heat externally ;
A highly conductive member provided between the metal substrate and the first heat absorbing member to electrically connect the metal substrate and the first heat absorbing member;
A deflection scanning apparatus characterized in that the metal substrate is grounded . In the deflection scanning apparatus according to claim 1, deflection run 査apparatus the first heat absorbing member is characterized by comprising a steel plate.

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