JP2012168469A - Scanner unit, laser scanning optical device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanner unit capable of suppressing a temperature rise in the scanner without enlarging the scanner while securing the dust resistance, and to provide a laser scanning optical device, and image forming apparatus.SOLUTION: The scanner unit includes: a polygon mirror 106; a motor 120 for rotatingly driving the polygon mirror 106; a substrate 102 in which a coil 120c of the motor 120 and a semiconductor element 130 for controlling the rotating drive of the motor 120 are disposed; and a storage housing 101 for storing the polygon mirror 106, the motor 120 and the substrate 102 in a dust-tight manner. The substrate 102 is disposed in the inner space of the storage housing 101 to halve the inner space into a first space A1 in which the motor 120 is disposed and a second space A2 in which the motor 120 is not disposed. The substrate 102 includes a plurality of heat radiating holes 104 for radiating the heat generated from the first space A1 in which the motor 120 is disposed, to the side of the space A2.

Description

  The present invention relates to a scanner unit, a laser scanning optical device, and an image forming apparatus.

  In the field of conventional laser scanning optical devices, for example, as disclosed in Japanese Patent Laid-Open No. 2000-338439 (Patent Document 1), a polygon in a space surrounded by a wall portion inside a casing covered with a cover is used. A configuration is disclosed in which a hole for heat dissipation is provided in a part of a cover corresponding to a space where no optical element such as a mirror or a lens system exists. Also disclosed is a configuration in which a hole, a notch, or the like is provided in the wall portion of the housing, and a space in which optical elements such as a polygon mirror and a lens system are present communicates with the outside of the housing.

JP 2000-338439 A

  In recent years, printing speeds have been increasing in image forming apparatuses such as laser printers and digital copying machines. In order to cope with this increase in speed, in the laser scanning optical device, a polygon mirror for deflecting and scanning the laser is rotated at a high speed.

  When the polygon mirror is rotated at a high speed, the amount of heat generated in the bearing portion and coil of the polygon motor and the driving semiconductor element portion of the polygon motor increases accordingly, and the temperature in the laser scanning optical device rises. As a result, there is a concern that thermal deformation of the scanning optical element or the like occurs, the beam irradiation position on the photoconductor changes, and the quality of the printed image in the image forming apparatus deteriorates.

  In particular, recently, in order to obtain high image quality, the resolution is increased and a high scanning density such as 1200 dpi is required, and it is necessary to maintain the beam irradiation position with high accuracy. For this reason, it is important to maintain the desired beam irradiation position by suppressing the temperature rise in the laser scanning optical apparatus.

  In the laser scanning optical apparatus disclosed in Japanese Patent Laid-Open No. 2000-338439 described above (Patent Document 1), a heat radiating hole is provided in a part of a cover corresponding to a space where there is no optical element such as a polygon mirror or a lens system. Therefore, the heat radiating holes are arranged outside the region where the optical elements such as the polygon mirror and the lens system exist. For this reason, the laser scanning optical device is enlarged in plan view.

  In addition, the space where the optical elements such as the polygon mirror and the lens system are present communicates with the outside through the holes and notches provided in the wall of the housing. Dust or the like adheres to the optical element. For this reason, the light quantity of the laser beam which irradiates the photoconductor decreases, and the quality of the printed image in the image forming apparatus deteriorates.

  An object of the present invention is to provide a scanner unit, a laser scanning optical device, and an image forming apparatus that can suppress an increase in temperature in the apparatus without increasing the size of the apparatus and ensuring dust resistance.

  The scanner unit according to the present invention is a scanner unit that deflects laser light emitted from a light source by a deflector, the deflector, a motor that rotationally drives the deflector, a coil of the motor, and A substrate on which a semiconductor element for controlling rotational driving of the motor is disposed; and a housing for housing the deflector, the motor, and the substrate in a dust-proof manner, wherein the substrate is an internal space of the housing case. The first space in which the motor is disposed is divided into a first space in which the motor is disposed and a second space in which the motor is not disposed, and the substrate is disposed in the first space in which the motor is disposed. A plurality of heat radiation holes for radiating the heat generated by the heat radiation to the second space side.

  In another embodiment, the housing case has a wall portion that partitions the first space in the first space into a first region in which the coil of the substrate is disposed and a second region in which the semiconductor element is disposed. A heat conducting member having better heat conduction than the substrate is disposed in the heat radiating hole provided in the substrate located in the first region.

  In another form, the heat conducting member is disposed in the second space on the opposite side of the first region across the substrate so as to cover the heat radiating hole.

  In another embodiment, the heat radiation hole provided in the substrate located in the first region covers both the surface and the end surface of the substrate in a state where the first space and the second space are communicated. The heat conducting member is disposed on the surface.

  In another embodiment, a heat radiating member is further arranged on the outer surface of the housing case that faces the second space.

  In another embodiment, the heat dissipation hole is disposed along a direction in which the heat dissipation member is provided.

  In the laser scanning optical device based on the present invention, the laser scanning optical apparatus includes a scanner unit in which a heat radiating fin is further provided on the outer surface of the housing case facing the second space, and a main body housing for housing the scanner unit, The main body housing includes an air inflow port for taking in air from the outside, and an open end of an air flow path formed by the heat radiating member faces the air inflow port.

  An image forming apparatus according to the present invention includes the above-described laser scanning optical device.

  According to the present invention, it is possible to provide a scanner unit, a laser scanning optical device, and an image forming apparatus that can suppress a temperature rise in the apparatus without increasing the size of the apparatus and ensuring dust resistance. Become.

It is a schematic block diagram which shows the color printer provided with the scanner unit and laser scanning optical apparatus in embodiment. It is sectional drawing of a laser scanning optical apparatus. It is a top view of a laser scanning optical apparatus. It is a bottom view of a laser scanning optical apparatus. It is a 1st perspective view of the scanner unit in an embodiment. It is a 2nd perspective view of the scanner unit in embodiment. It is a top view of the scanner unit in an embodiment. FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7. It is an expanded partial sectional view which shows the other heat conductive structure around the hole for heat radiation in embodiment. It is a top view which shows the relationship between the position of the hole for thermal radiation provided in the scanner unit in other embodiment, the position of a thermal radiation fin, and the position of the air inflow port provided in a laser scanning optical apparatus. It is a figure which shows an example of a heat conductive member material.

  Hereinafter, a scanner unit according to an embodiment of the present invention, a laser scanning optical apparatus including the scanner unit, and an image forming apparatus including the laser scanning optical apparatus will be described with reference to the drawings. Note that in the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated. In addition, it is planned from the beginning to use the structures in the embodiments in appropriate combinations.

  In the following, a color printer adopting a general full-color electrophotographic system is described as an example of an image forming apparatus, but the present invention is not limited to the full-color electrophotographic system. Also, it can be applied to a printer that employs one type of laser scanning optical device (such as black) that forms only a monochrome image. In addition to a printer, a scanner unit and a laser scanning optical device according to the present invention can be mounted on an image forming apparatus such as a copying machine or a FAX.

(See the overall configuration of the color printer 1, FIG. 1)
FIG. 1 shows a schematic configuration of a color printer 1 equipped with a laser scanning optical device 20 according to the present invention. The color printer 1 is configured to synthesize four color images in a tandem manner.

  An intermediate transfer belt 10 is disposed immediately above the four image forming stations 2 (2Y, 2M, 2C, 2K), and a laser scanning optical device 20 is disposed immediately below. Each image forming station 2 is provided with a photosensitive drum 3 (3Y, 3M, 3C, 3K), a developing device 4 (4Y, 4M, 4C, 4K), a charger (not shown), a residual toner cleaner, and the like. ing. Note that the image forming station 2K for forming a black image is configured in a large size so that a frequently used monochrome image can be formed at high speed.

  The laser scanning optical device 20 forms an image (electrostatic latent image) on each photosensitive drum 3 by the light beams By, Bm, Bc, and Bk emitted based on the Y, M, C, and K image data. This latent image is visualized with toner.

  The intermediate transfer belt 10 is stretched endlessly around the drive roller 11 and the support roller 12. On the intermediate transfer belt 10, the toner images of the respective colors formed on the respective photosensitive drums 3 based on the rotation in the arrow Y direction are sequentially primary-transferred and synthesized.

  The recording paper P is stored in the automatic paper cassette 5 and is fed one by one at a predetermined timing. The synthetic toner image is secondarily transferred onto the recording paper P from the intermediate transfer belt 10 at the secondary transfer position 13 via the paper passing path 6. The recording paper P that has been secondarily transferred is subjected to heat fixing of the toner by the fixing device 15 and then discharged from the discharge roller 16 onto the paper discharge unit 9.

  When performing double-sided printing on the recording paper P, the recording paper P is conveyed from the switchback roller 17 to the outside of the color printer 1, switched back, and returned to the secondary transfer position 13 via the reverse path 7. It is. Here, the recording paper P on which the toner image is secondarily transferred on the back surface is discharged from the discharge roller 16 onto the paper discharge unit 9.

(Schematic configuration of the laser scanning optical device 20, see FIGS. 2 to 4)
2 is a cross-sectional view of the laser scanning optical device 20, FIG. 3 is a plan view, and FIG. 4 is a bottom view. The laser scanning optical device 20 includes a light source unit 21, a scanner unit 100 including a polygon mirror 106 as an example of a deflector, first and second imaging lenses 31, 32, and a folding mirror 34 provided for each optical path. 35, 36 and the third imaging lens 33, and a housing 27 for holding these members. The detailed structure of the scanner unit 100 will be described later.

  The light source unit 21 includes a laser diode 22 (22Y, 22M, 22C, 22K), a composite mirror 23 (23Y, 23M, 23C), a folding mirror 24, and a cylindrical lens 25, and is mounted on a plate 26. Yes.

  The light beam emitted from the laser diode 22K is guided to the folding mirror 24. Further, the light beams emitted from the laser diodes 22C, 22M, and 22Y are reflected by the combining mirrors 23C, 23M, and 23Y, respectively, and guided to the folding mirror 24. Each light beam reflected by the folding mirror 24 is condensed in the sub-scanning direction Z (see FIG. 2) by the cylindrical lens 25 and guided to the same surface of the polygon mirror 106 with a predetermined angle in the sub-scanning direction Z.

  These light beams are deflected at a constant angular velocity in the main scanning direction X (see FIG. 3) based on the rotation of the polygon mirror 106, and pass through the first and second imaging lenses 31 and 32. The light beam Bk passes through the third imaging lens 33K, is reflected by the folding mirror 34K, and exposes and scans on the photosensitive drum 3K. The light beam Bc is reflected by the folding mirrors 34C and 35C, passes through the third imaging lens 33C, is further reflected by the folding mirror 36C, and exposes and scans the photosensitive drum 3C.

  The light beam Bm is reflected by the folding mirror 34M, passes through the third imaging lens 33M, is further reflected by the folding mirror 35M, and exposes and scans the photosensitive drum 3M. The light beam By is reflected by the folding mirror 34Y, passes through the third imaging lens 33Y, is further reflected by the folding mirror 35Y, and exposes and scans the photosensitive drum 3Y.

  In order to detect the writing position of each scanning line on each photosensitive drum 3, that is, to obtain a main scanning synchronization signal, the upstream side beam in the main scanning direction of the beam Bk deflected by the polygon mirror 106 is shown in FIG. As shown, the light is reflected by the detection mirror 37, condensed by the lens 38, and enters the sync signal detection light receiving sensor 39.

  The casing 27 is fixed to a frame (not shown) of the color printer 1 by, for example, screwing at three fixing points Z1, Z2, and Z3 (see FIG. 3).

  Further, as shown in FIG. 3, a partial magnification adjustment mechanism 45 and a skew adjustment mechanism 50 are installed as color misregistration adjustment (registration adjustment). The skew adjustment mechanism 50 includes a stepping motor 51 fixed to the casing 27 via a bracket 59 as a drive source. Detailed descriptions of the partial magnification adjustment mechanism 45 and the skew adjustment mechanism 50 are omitted.

(Scanner unit 100)
Next, the scanner unit 100 according to the present embodiment will be described with reference to FIGS. 5 and 6 are first and second perspective views of the scanner unit 100, FIG. 7 is a plan view of the scanner unit 100, and FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG.

  The scanner unit 100 deflects a laser beam emitted from a laser diode 22 (22Y, 22M, 22C, 22K) as a light source by a polygon mirror 106. The housing 101 has a cubic shape as a whole, and includes a cylindrical main body case 101b having an open upper surface and a case cover 101a. The case cover 101a is fixed to the main body case 101b with squares using screws or the like. The housing 101 is fixed to the housing 27 with screws using a flange portion 111f provided on the main body case 101b.

  On the side surface in the longitudinal direction of the main body case 101b, an elongated opening 103 through which laser light enters and exits is provided. On the upper surface of the case cover 101a, as an example of a heat radiating member, a plurality of heat radiating fins 101f extending along the diagonal direction are provided. The form of the heat dissipating fins 101f is not limited to the form shown in the figure, and is appropriately designed so that the cooling efficiency is maximized along the air cooling air flow direction employed in the laser scanning optical device 20. In consideration of cooling efficiency, the heat dissipating fins 101f may not be provided.

  A substrate 102 is accommodated inside the main body case 101b. The substrate 102 is arranged in the internal space of the housing 101 so as to be divided into a first space A1 and a second space A2 with the substrate 102 as a boundary. Specifically, a wall portion 107 standing from the bottom surface side is provided inside the main body case 101 b, and the substrate 102 is positioned using the top portion of the wall portion 107.

  A motor 120 for rotationally driving the polygon mirror 106 is disposed on the first space A1 side (in the drawing, the lower surface side of the substrate 102). In addition, on the surface of the substrate 102 on the first space A1 side, a coil 120c constituting the motor 120 and a semiconductor element 130 for controlling the rotational drive of the motor 120 are disposed.

  The first space A1 is partitioned into a first region A11 in which the coil 120c of the substrate 102 is disposed and a second region A12 in which the semiconductor element 130 is disposed by the wall portion 107 located substantially at the center.

  The substrate 102 is formed with a plurality of heat radiation holes 104 for radiating heat generated in the first space A1 in which the motor 120 and the semiconductor element 130 are disposed to the second space A2 side. As indicated by the arrows in FIG. 8, the heat generated by the motor 120 (particularly, the bearing portion and the coil 120 c) and the semiconductor element 130 by the heat radiating hole 104 is a second position located above the first space A <b> 1. Heat is dissipated toward the space A2. In addition, although the hole diameter of the hole 104 for heat dissipation is various according to an apparatus, it is about 1 mm-about 10 mm in diameter.

  Since the housing 101 needs to prevent dust from adhering to the polygon mirror 106 housed therein (dust-proof), the opening 103 is fitted with transparent glass or a resin member. The case cover 101a is attached to the main body case 101b so as to ensure airtightness.

  In the present embodiment, a heat conduction member 105 that is superior in heat conduction to the substrate 102 is disposed in the heat radiation hole 104 provided in the substrate 102 located in the first region A11. Specifically, a heat conducting member 105 is provided in the second space A2 on the opposite side of the first region A11 across the substrate 102 so as to cover the heat radiation hole 104.

  Glass epoxy resin is used for the substrate 102, and its thermal conductivity is about 0.35 W / mk. On the other hand, the heat conductive member 105 is made of heat conductive silicone that has better heat conductivity than the substrate 102. FIG. 11 shows a specific material of the heat conductive silicone and its heat conductivity. In addition, FIG. 11 is a figure which shows an example of a heat conductive member material.

  As described above, when the scanner unit 100 according to the present embodiment is used, the heat generated in the first space A1 by the convection is generated in the second space because the substrate 102 is provided with the plurality of heat radiation holes 104. Heat can be dissipated toward the space A2.

  Further, in the second space A2 on the opposite side to the first region A11 considered to have a large heat dissipation amount, heat dissipation silicone is disposed as the heat conductive member 105, so that heat dissipation provided on the upper surface of the case cover 101a. Heat can be efficiently transferred to the fins 101f. If necessary, the heat conducting member 105 can be provided also in the second space A2 on the opposite side to the second region A12.

  Further, since the heat radiation hole 104 provided in the first area A11 where the polygon mirror 106 is located is covered with the heat conducting member 105, the entry of dust and the like from the heat radiation hole 104 is prevented, and the polygon mirror It is also possible to prevent accumulation of dust or the like on 106.

  As a result, the scanner unit 100 which can suppress the temperature rise in the apparatus without increasing the size of the apparatus and ensuring the dustproof property, the laser scanning optical apparatus 20 using the scanner unit 100, and the laser A color printer 1 using the scanning optical device 20 can be provided.

  Since the housing 101 is provided so as to ensure airtightness, there may be a case where dust or the like does not pose a problem from the heat radiation hole 104 to the first area A11 where the polygon mirror 106 is located. .

  In this case, as shown in FIG. 9, in a state where the first space A1 and the second space A2 are communicated with the heat radiation hole 104 instead of the heat conductive silicone, the both surfaces and end surfaces of the substrate 102 are covered. A metallic heat conduction member 108 having better heat conduction than the substrate 102 may be provided. Copper is used as an example of the metal material. The thermal conductivity is about 398 W / mk. FIG. 9 is an enlarged partial sectional view showing another heat conducting structure around the heat radiation hole 104.

  Thereby, the amount of heat transfer around the heat radiating hole 104 is increased, and the heat generated inside the first space A1 by convection can be efficiently radiated toward the second space A2 side.

  Here, another embodiment will be described with reference to FIG. FIG. 10 is a plan view showing the relationship between the positions of the heat radiation holes provided in the scanner unit, the positions of the heat radiation fins, and the positions of the air inlets provided in the laser scanning optical device.

  As shown in FIG. 10, with respect to the positions of the plurality of heat radiation holes 104 provided in the substrate 102, the heat radiation holes 104 are arranged along the direction in which the heat radiation fins 101f are provided, so that heat can be radiated more efficiently. . 10 is formed so as to include an arc-shaped portion and a straight-shaped portion from one side in the longitudinal direction to one side in the short direction of the housing case 101. Has been.

  It is also possible to employ a configuration that promotes heat dissipation in the housing 27 of the laser scanning optical device 20 that houses the scanner unit 100. For example, as shown in FIG. 10, an air inlet 27 h that opens a part of the housing 27 and takes in air from the outside at a position where the opening end 101 h of the air flow path 101 g formed by the plurality of heat radiating fins 101 f faces. Is provided. By using the external fan 114 to send air (AF) from the air inlet 27h into the housing 27, the air (AF) passes through the air flow path 101g formed by the plurality of radiating fins 101f. It is possible to pass through and dissipate heat efficiently.

  In each of the above embodiments, the case where the polygon mirror 106 is used as an example of the deflector has been described. However, a resonant scanner, a galvanometer mirror, or the like can be used instead of the polygon mirror 106.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 color printer, 2, 2K image forming station, 3, 3C, 3K, 3M, 3Y photosensitive drum, 4 developing unit, 5 automatic paper feed cassette, 6 paper feed path, 7 reversing path, 9 paper discharge unit, 10 intermediate Transfer belt, 11 drive roller, 12 support roller, 13 secondary transfer position, 15 fixing device, 16 discharge roller, 17 switchback roller, 20 laser scanning optical device, 21 light source unit, 22, 22C, 22M, 22Y, 22K laser Diode, 23, 23C, 23M, 23Y Composite mirror, 24, 34, 35, 36, 34C, 35C, 34M, 34Y Folding mirror, 25 Cylindrical lens, 26 plate, 27 housing, 27A Polygon mirror housing housing, 27h Air Inflow port, 31 1st imaging lens, 32 2nd imaging lens, 33, 33C 33K, 33M, 33Y Third imaging lens, 34K, 35M, 35Y, 36C mirror, 37 detection mirror, 38 lens, 39 sync signal detection light receiving sensor, 43 heat radiation fin, 45 partial magnification adjustment mechanism, 50 skew adjustment mechanism 51 Stepping motor, 59 Bracket, 100 Scanner unit, 101 Housing, 101a Case cover, 101b Body case, 101f Radiation fin, 101g Air flow path, 101h Open end, 102 Substrate, 103 opening, 104 Heat dissipation hole, 105, 108 Thermal conduction member, 106 Polygon mirror, 107 Wall part, 111f Flange part, 114 External fan, 120 Motor, 120c Coil, 130 Semiconductor element.

Claims (8)

A scanner unit that deflects laser light emitted from a light source by a deflector,
The deflector;
A motor for rotationally driving the deflector;
A substrate on which a coil of the motor and a semiconductor element that controls rotation driving of the motor are disposed;
A housing for dust-proofing and housing the deflector, the motor, and the substrate;
The substrate is arranged so as to be divided into a first space in which the motor is disposed and a second space in which the motor is not disposed, with the substrate as a boundary, in the internal space of the housing case,
The substrate unit includes a plurality of heat radiation holes for radiating heat generated by the first space in which the motor is disposed to the second space side. The housing includes a wall portion that partitions the first space in the first space into a first region in which the coil of the substrate is disposed and a second region in which the semiconductor element is disposed.
2. The scanner unit according to claim 1, wherein a heat conduction member having better heat conduction than the substrate is disposed in the heat radiation hole provided in the substrate located in the first region.   3. The scanner unit according to claim 2, wherein the heat conducting member is disposed so as to cover the heat radiating hole in the second space opposite to the first region across the substrate.   The heat conduction member covers the both surfaces and the end surface of the substrate in a state where the first space and the second space are communicated with the heat radiation hole provided in the substrate located in the first region. The scanner unit according to claim 2, wherein   5. The scanner unit according to claim 1, wherein a heat radiating member is further disposed on an outer surface of the housing case facing the second space.   The scanner unit according to claim 5, wherein the heat radiation hole is disposed along a direction in which the heat radiation member is provided. The scanner unit according to claim 5 or 6,
A main body housing for accommodating the scanner unit,
The main body housing includes an air inlet for taking in air from the outside,
The laser scanning optical device, wherein an open end of an air flow path formed by the heat radiating member faces the air inlet.   An image forming apparatus comprising the laser scanning optical apparatus according to claim 7.

Images