Optical scanner having heat flow channel to transfer heat to collimating lens

Abstract

The optical scanner (3) includes a light source (301), a collimator lens (302) for converting light radiated from the light source (301) into collimated light, and a deflector (310) located on a downstream side of the collimator lens (302) for deflecting the light in a main scanning direction (X). The optical scanner (3) comprises a heat flow channel (33) for transferring heat from the deflector to the collimating lens (302).

Description

Background Art

[0001] The electrostatic photographic printing device prints an image by developing the electrostatic latent image formed on the photoconductor into a visible toner image, and transferring and fixing the toner image to the printing medium. The printing device uses an optical scanner to irradiate the photoconductor with light modulated according to the image information. The optical scanner deflects the light irradiated from the light source in the main scanning direction through a deflector. The deflector includes a motor and a deflection mirror coupled to the rotating shaft of the motor. The deflection mirror includes a reflection surface that reflects the light emitted from the light source. When the deflection mirror rotates, the angle between the light and the reflection surface changes, so that the light can be scanned in the main scanning direction. The light reflected by the reflection surface forms a light spot on the photoconductor through an imaging optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Figure 1 is a schematic diagram of an example of an optical scanner.

[0003] Figure 2 It is taken along the line X1-X1' Figure 1 A cross-sectional view of an example of an optical scanner shown in FIG.

[0004] Figure 3 is a schematic diagram of an example of an optical scanner.

[0005] Figure 4 is a graph showing the temperature difference between the light source and the collimating lens when no heat flow channel exists.

[0006] Figure 5 is a graph showing the temperature difference between the light source and the collimating lens when a convection channel is present.

[0007] Figure 6 is a graph showing changes in the focus position on the object to be exposed and the main scanning beam diameter according to the image height on the object to be exposed.

[0008] Figure 7 is a graph showing changes in the focus position on the object to be exposed and deviations in the main scanning beam diameter.

[0009] Figure 8 is a schematic plan view of an example of an optical scanner.

[0010] Fig. 9 It is taken along the line X2-X2' Figure 8 A cross-sectional view of an example of an optical scanner shown in FIG.

[0011] Fig.10 is a schematic diagram of an example of an optical scanner.

[0012] Fig.11is a schematic diagram of an example of a printing apparatus using an optical scanner. DETAILED DESCRIPTION

[0013] The electrostatic photographic printing device forms an electrostatic latent image to print an image by scanning light on a photoconductor using an optical scanner, wherein the light is modulated according to an image signal; developing the electrostatic latent image into a visible toner image; and transferring and fixing the toner image to a print medium. The optical scanner includes a light source, a deflector for deflecting light in a main scanning direction, and an imaging optical system for scanning the deflected light at a constant speed on a photoconductor (an object to be exposed) to form an image. A collimating lens for converting divergent light from a light source into collimated light is disposed between the light source and the deflector.

[0014] The internal temperature of the optical scanner changes during printing due to external factors or heat generated by internal components, and the change may be as much as 50° C. depending on the printing speed. Factors that change the temperature of the optical scanner may include temperature changes in the external environment of the printing device, heat from a fuser, heat transfer from print media stacked on a paper output tray of the printing device after output, etc. In addition, heat generated by components included in the optical scanner, such as heat generated by a motor driver integrated circuit (IC) of a motor driving a deflector, may also be a factor that increases the temperature of the optical scanner.

[0015] The optical characteristics of the collimating lens are affected by temperature. When the internal temperature of the optical scanner increases, the refractive index and curvature of the collimating lens change, thereby changing the focal position of the optical system in the optical scanner. Then, the beam diameter on the photoconductor increases, and printing defects such as stripes along the sub-scanning direction appear in the printed image. In addition, when the optical scanner starts to operate, the temperature of the light source rises rapidly, and the temperature difference between the light source and the collimating lens also changes the focal position of the optical system. When the optical scanner adopts a long focal length optical system, the change in the focal position due to the temperature difference between the light source and the collimating lens may be greater, which in turn has a greater impact on the quality of the printed image.

[0016] The optical scanner according to the present disclosure has a structure that reduces the temperature difference between the light source and the collimating lens. According to some examples, the optical scanner includes a light source, a collimating lens for converting the light radiated from the light source into collimated light, a deflector located on the downstream side of the collimating lens for deflecting the light along the main scanning direction, and a heat flow channel for transferring heat from the deflector to the collimating lens. The deflector may include a deflecting mirror and a motor for rotating the deflecting mirror. When the optical scanner is driven, the light source and the motor are driven, and heat is generated from the light source and the motor driver IC for driving the motor. The heat generated from the deflecting mirror is transferred to the collimating lens through the heat flow channel. Accordingly, even when the temperature of the light source rises rapidly, the heat is transferred from the deflector to the collimating lens along the heat flow channel, whereby the temperature of the collimating lens also rises rapidly. Therefore, the temperature difference between the light source and the collimating lens can be reduced, and the change in the focal position caused by the temperature difference between the light source and the collimating lens can be reduced.

[0017] The heat flow channel can be implemented in various ways to transfer heat from the deflector to the collimating lens, for example, by convection or conduction. For example, the heat flow channel can be implemented by a convection channel, through which heat is transferred from the deflector to the collimating lens by convection. The optical scanner may include an optical frame, which includes a lower frame and an upper frame covering the upper portion of the lower frame, and forms a receiving space for accommodating a light source, a collimating lens, and a deflector. The convection channel can be formed by an upper wall of the upper frame that partially protrudes upward. The optical path between the collimating lens and the deflector is partially separated from the internal space of the optical scanner by a rib structure or the like, so that unnecessary light does not enter the deflector. Therefore, the convection heat transfer through the optical path may not be enough to increase the temperature of the collimating lens. The convection channel forms a heat transfer channel between the deflector and the collimating lens by convection, thereby reducing the temperature difference between the light source and the collimating lens. For example, the width of the convection channel on the collimating lens side may be less than the width on the deflector side. Accordingly, the heat from the deflector can be concentratedly transferred to the collimating lens.

[0018] For example, the heat flow path can be implemented by a heat conductor extending from the deflector toward the collimating lens and transferring heat by conduction. For example, the deflector can include a support plate on which the motor is supported. The heat conductor can be in contact with both the support plate and the collimating lens, or with one of them. The heat from the deflector can be directly transferred to the collimating lens via the heat conductor.

[0019] By dissipating the heat generated from the light source, the temperature difference between the light source and the collimating lens can be reduced. For example, the optical scanner may include a heat sink that contacts the light source and dissipates the heat generated from the light source. The heat sink may be arranged outside the optical frame. Accordingly, the heat generated from the light source may be dissipated to the outside of the optical scanner.

[0020] For example, the collimating lens may include a diffractive optical element (DOE) collimating lens. The DOE collimating lens may be a lens including a light incident surface on which a diffraction pattern is formed. When the temperature of the optical scanner is constant, the diffraction pattern may reduce the change in the focus position.

[0021] According to some examples, the optical scanner includes: a light source; a collimating lens for converting light radiated from the light source into collimated light; a deflector located on the downstream side of the collimating lens for deflecting the light along the main scanning direction; and an optical frame for forming a space for accommodating the light source, the collimating lens and the deflector, wherein the area of ​​the upper frame of the optical frame located between the deflector and the collimating lens partially protrudes upward to form a convection channel for transferring heat from the deflector to the collimating lens by convection. The optical scanner may include the above-mentioned thermal conductor. The optical scanner may include the above-mentioned heat sink.

[0022] According to some examples, the printing device includes a photoconductor and the above-mentioned optical scanner to form an electrostatic latent image by irradiating the photoconductor with light. Examples of the optical scanner and the printing device using the optical scanner are described below. Devices performing the same function are represented by the same reference numerals, and redundant descriptions thereof may be omitted.

[0023] Figure 1 is a schematic diagram of an example of the optical scanner 3 . Figure 2 It is taken along the line X1-X1' Figure 1 A cross-sectional view of an example of an optical scanner 3 is shown in FIG. Figure 1 In , X represents the main scanning direction, Y represents the optical axis direction of the imaging optical system, and Z represents the sub-scanning direction. Figure 1 , the upper frame 32 is shown. Figure 1 and Figure 2 The optical scanner 3 may include a light source 301, a collimating lens 302 for converting the light L radiated from the light source 301 into collimated light (see Figure 2 ), a deflector 310 for deflecting light on the downstream side of the collimating lens 302 along the main scanning direction X according to the traveling direction of the light L, and a heat flow channel 33 for transferring heat from the deflector 310 to the collimating lens 302.

[0024] The optical scanner 3 may include an optical frame 30, which forms a receiving space 34 to receive optical elements such as a light source 301, a collimating lens 302, a deflector 310, and an imaging optical system 390. The optical frame 30 may include a lower frame 31 and an upper frame 32, and the upper frame 32 covers an upper portion of the lower frame 31 to form the receiving space 34. Optical elements of the optical scanner 3 such as the light source 301, the collimating lens 302, the deflector 310, and the imaging optical system 390 may be supported by the lower frame 31. The optical frame 30 may include a supporting frame 35 coupled to an outer portion of the lower frame 31 in the main scanning direction X. The optical path 303 provides a passage through which the light L passes, and the optical path 303 is disposed between the collimating lens 302 and the deflector 310 in the receiving space 34 of the optical frame 30. The optical path 303 is partially separated from the receiving space 34 by a rib structure 304 so that unnecessary light does not enter the deflector 310. In other words, the optical path 303 has openings on the collimating lens 302 side and on the deflector 310 side, and may be formed by the bottom 305 of the lower frame 31 , the upper wall 329 of the upper frame 32 , and the rib structure 304 .

[0025] For example, the light source 301 can be a laser light source. For example, the light source 301 can be supported by the side of the lower frame 31 in the main scanning direction X. In these examples, the light source 301 can be coupled to the support frame 35. The light source 301 can be mounted on a light source driving circuit board (not shown), and the light source driving circuit board can be coupled to the support frame 35. Accordingly, the light source 301 can be accommodated in the accommodating space 34 of the optical frame 30. A cylindrical lens (not shown) can be arranged between the collimating lens 302 and the deflector 310. For example, the cylindrical lens can have a refractive power in the sub-scanning direction (Z direction). The cylindrical lens focuses the light L (i.e., collimated light) passing through the collimating lens 302 onto the reflective surface of the deflection mirror 314 of the deflector 310.

[0026] The deflector 310 may include a deflection mirror 314 for deflecting the light L along the main scanning direction X and a motor 315 for rotating the deflection mirror 314. The deflection mirror 314 includes a reflective surface. The motor 315 includes a stator (not shown) and a rotor (not shown) that rotates by electromagnetic interaction with the stator. The deflection mirror 314 is coupled to the rotation axis of the rotor of the motor 315. The deflector 310 may include a circuit board 312. The circuit board 312 may include a current supply circuit that provides current to the stator, and may include a motor drive IC 313 for driving the motor 315. The motor 315 and the circuit board 312 may be supported by a support plate 311. For example, the rotation axis of the rotor of the motor 315 may be supported by the support plate 311. The support plate 311 is coupled to the lower frame 31 of the optical frame 30. The support plate 311 may be made of a metal having high rigidity and high thermal conductivity.

[0027] The imaging optical system 390 forms an image of the light L deflected by the deflector 310 on the surface to be scanned of the object to be exposed (i.e., the outer circumferential surface of the photoconductor). The optical axis of the imaging optical system 390 extends in the Y direction perpendicular to the main scanning direction X. The imaging optical system 390 may be an f-theta (f-θ) lens that forms an image by scanning the light L at a constant speed on the object to be exposed. The imaging optical system 390 may have an optical shape formed based on, for example, the distance between the imaging optical system 390 and the light deflector 310 and the distance between the deflector 310 and the object to be exposed.

[0028] The collimating lens 302 may be, for example, a glass lens. In order to reduce costs, the collimating lens 302 may be a plastic lens. The collimating lens 302 may be a diffractive optical element (DOE) collimating lens. The DOE collimating lens may be a lens including a light incident surface on which a diffractive optical element is disposed and light is incident from the light source 301. When the temperature of the optical scanner 3 is uniform, the diffractive optical element may reduce the change in the focus position. The change in the focus position refers to the change in the focus position in the optical axis direction (Y). In the following, it is assumed that when the focus is formed on the object to be exposed, the change in the focus position is "0"; when the focus is formed in front of the object to be exposed, the focus position moves in the -Y direction; when the focus is formed behind the object to be exposed, the focus position moves in the +Y direction. The DOE collimating lens may be a plastic lens. In some examples, the collimating lens 302 may be a DOE collimating lens made of plastic.

[0029] When the optical scanner 3 and the printing device including the optical scanner 3 are in operation, the internal temperature of the optical scanner 3 may increase due to heat from the fuser, heat transfer from the print media stacked on the paper discharge tray of the printing device, heat from the motor driver IC 313 of the deflector 310, or the like. When the internal temperature of the optical scanner 3 increases, the refractive index and curvature of the collimator lens 302 may change. For example, when the internal temperature of the optical scanner 3 increases, the refractive index and curvature of the collimator lens 302 may decrease. Then, the focal position generated by the optical element of the optical scanner 3 may move toward the +Y direction. When the collimator lens 302 is made of plastic, the change in its refractive index and curvature is greater than that of the collimator lens 302 made of glass. When the internal temperature of the optical scanner 3 is substantially uniform, the diffractive optical element of the collimator lens 302 can reduce the change in the focal position caused by the change in the refractive index and curvature. The diffractive optical element of the collimating lens may be designed to reduce the change in the focal position when the temperature of the optical system in the optical scanner 3 including the light source 301 is uniform, by, for example, taking into account the change in the wavelength of the light L according to the temperature change of the light source 301. For example, when the internal temperature of the optical scanner 3 increases and the focal position generated by the optical element of the optical scanner 3 moves toward the +Y direction, the diffractive optical element of the collimating lens may be designed to reduce the amount of change in the focal position in the +Y direction.

[0030] However, the temperature of the light source 301 may rise rapidly when the optical scanner 3 starts to operate. Then, due to the characteristics of the laser light source 301, the wavelength of the emitted light may increase. The diffractive optical element of the collimating lens 302 is affected by the wavelength and the temperature. When the wavelength of the light incident on the diffractive optical element of the collimating lens 302 increases, the diffraction effect is greater than the refraction effect, so the focal position moves further in the -Y direction. In terms of the temperature difference between the light source 301 and the collimating lens 302, the focal position may move further as the temperature difference increases. The temperature difference between the light source 301 and the collimating lens 302 may be reduced to prevent the focal position from moving further.

[0031] In order to prevent the focus position from further moving, the temperature of the collimating lens 302 may be quickly increased by, for example, transferring heat from other optical elements in the optical scanner 3 to the collimating lens 302, thereby reducing the temperature difference between the light source 301 and the collimating lens 302. Among the optical elements of the optical scanner 3, the temperature of the deflector 310 increases rapidly. Therefore, the heat generated from the deflector 310 may be transferred to the collimating lens 302. In some examples, the optical scanner 3 may include a heat flow channel 33 to transfer heat from the deflector 310 to the collimating lens 302. The heat flow channel 33 may be implemented in various forms to transfer heat from the deflector 310 to the collimating lens 302 by, for example, convection and / or conduction.

[0032] For example, refer to Figure 1 and Figure 2 , the heat flow channel 33 can be implemented by the convection channel 320 to transfer heat from the deflector 310 to the collimating lens 302 by convection. The convection channel 320 can extend from the deflector 310 to the collimating lens 302. The convection channel 320 can be formed by the upper wall 329 of the upper frame 32 that partially protrudes upward. The convection channel 320 can be formed below the protruding portion 328 (protrusion) of the upper wall 329. When the deflector 310 is driven, heat is generated in the motor driver IC 313. The heat increases the temperature of the air around the deflector 310, and the high-temperature air flows along the convection channel 320 to the collimating lens 302 to increase the temperature of the collimating lens 302. Therefore, the temperature difference between the light source 301 and the collimating lens 302 can be reduced. The airflow generated by the rotation of the deflection mirror 314 promotes the movement of air through the convection channel 320. Therefore, heat transfer from the deflecting mirror 310 to the collimating lens 302 can be promoted.

[0033] The width of the convection channel 320 may be narrower on the collimating lens 302 side than on the deflector 310 side. For example, the convection channel 320 may include a first region 321 above the deflector 310 and a second region 322 extending from the first region 321 toward the collimating lens 302. The width of the second region 322 may be smaller than the width of the first region 321. In other words, the width W2 of the second end 324 of the convection channel 320 on the collimating lens 302 side may be shorter than the width W1 of the first end 323 on the deflector 310 side. Figure 1 and Figure 2 In the example shown, the width of the second region 322 of the convection channel 320 can gradually decrease from the deflector 310 side toward the collimating lens 302. Therefore, the heat from the deflector 310 can be concentratedly transferred to the collimating lens 302, so that the temperature difference between the light source 301 and the collimating lens 302 can be effectively reduced.

[0034] For example, the convection channel 320 may be disposed above the optical path 303 and communicate with the optical path 303. The optical path 303 may be a path for heat convection between the deflector 310 and the collimating lens 302. Therefore, the optical path 303 and the convection channel 320 may function as a convection heat transfer channel as a whole, and may effectively reduce the temperature difference between the light source 301 and the collimating lens 302.

[0035] Figure 3 is a schematic diagram of an example of the optical scanner 3. Figure 1 and Figure 2 Compared to the example of the optical scanner 3 shown in Figure 3 The convection channels 320 have different shapes. Figure 3A partial cross section of the convection channel 320 is shown in FIG. The following mainly describes the differences. Figure 3 , the convection channel 320 may include a first area 321 above the deflector 310 and a second area 322 extending from the first area 321 toward the collimating lens 302. The widths of the first area 321 are substantially the same. The widths of the second area 322 are substantially the same. The width of the second area 322 is shorter than the width of the first area 321. Therefore, the convection channel 320 is realized by the first area 321 having a first width and the second area 322 having a second width and being stepped with the first area 321. Through this structure, the heat from the deflector 310 can be concentratedly transferred to the collimating lens 302, so that the temperature difference between the light source 301 and the collimating lens 302 can be reduced.

[0036] Figure 4 is a graph showing the temperature difference between the light source 301 and the collimating lens 302 when the heat flow channel 33 is not present. Figure 5 is a graph showing the temperature difference between the light source 301 and the collimating lens 302 when the convection channel 320 is present. The test conditions are as follows.

[0037] Printing device: For A3

[0038] Print resolution: 600 dots per inch (dpi)

[0039] Print speed: 31 pages per minute (ppm)

[0040] Speed ​​of motor 315: 25,600 (rpm)

[0041] Light source 301: a laser diode with two light-emitting points

[0042] Collimating lens 302: DOE collimating lens

[0043] Test method: Print a test page continuously for 20 minutes at room temperature

[0044] exist Figure 4 and Figure 5 , T1 represents the temperature of the light source 301, T2 represents the temperature of the collimating lens 302, and T12 represents the difference between the temperature of the light source 301 and the temperature of the collimating lens 302. Figure 4 , without heat flow channel, T12 can reach up to 3.8℃. Figure 5 , in the case of the convection channel 320, T12 can reach up to 2.5°C, and the temperature difference is reduced by about 34%.

[0045] Figure 6is a graph showing changes in the focal position on the object to be exposed and the main scanning beam diameter according to the image height (position in the main scanning direction X) on the object to be exposed. Figure 7 is a graph showing changes in the focus position on the object to be exposed and deviations in the main scanning beam diameter. Figure 6 In the figure, the reference symbol D is shown with a number in parentheses, which indicates the image height on the object to be exposed. For example, D(150) indicates an image height of 150 mm and represents a position 150 mm away from the optical axis of the imaging optical system 390 in the main scanning direction X. Figure 6 and Figure 7 In FIG. 1 , R1 represents the process deviation of the change of the focus position generated during the manufacturing process of the optical scanner 3, and R1 may be approximately ±0.5 mm. R2 represents the change of the focus position when there is no heat flow channel 33. R3 represents the change of the focus position when there is a convection channel 320.

[0046] When there is no heat flow channel 33 and the temperature difference T12 between the light source 301 and the collimating lens 302 is about 3.8°C, R2 is about 1.4 mm, and considering the process deviation, the maximum value of the change in the focus position is about 1.9 mm. In this case, Figure 6 As shown in , the maximum value of the main scanning beam diameter is about 105 μm, and the deviation of the main scanning beam diameter is about 32 μm. For example, when the main scanning beam diameter is greater than 95 μm or the beam diameter deviation at each position in the main scanning direction X is greater than or equal to 20 μm, stripes along the sub-scanning direction may be generated in the printed image, resulting in poor printing quality.

[0047] like Figure 5 As shown in FIG. 3 , when the convection channel 320 is present, the temperature difference T12 between the light source 301 and the collimating lens 302 is at most 2.5° C. In this case, R2 is about 0.9 mm, and considering the process deviation, the maximum value of the change in the focus position is about 1.4 mm. In this case, as Figure 6 As shown in , the maximum value of the main scanning beam diameter is about 91 μm, and the deviation of the main scanning beam diameter is about 19 μm. Therefore, quality defects in the printed image can be reduced or avoided.

[0048] The above test results are summarized in Table 1.

[0049] [Table 1]

[0050]

[0051] As described above, by adopting the convection channel 320 as the heat flow channel 33, the change in the focal position, the increase in the beam diameter, and the deviation in the beam diameter according to the temperature difference between the light source 301 and the collimator lens 302 can be reduced, and the printing quality can be improved. In addition, since the deflector 310 as a heat source is larger in size than the collimator lens 302, the heat transfer efficiency can be improved by making the convection channel 320 narrower on the DOE collimator lens 302 side than on the deflector 310 side. By adopting the heat flow channel 33, a plastic collimator lens that is relatively sensitive to temperature but inexpensive can be used, and further, a plastic DOE collimator lens that can reduce the change in the focal position at a uniform temperature can also be used.

[0052] For example, the heat flow channel 33 may have a structure in which heat from the deflector 310 is transferred to the collimating lens 302 by conduction. Figure 8 is a schematic plan view of an example of the optical scanner 3 . Fig. 9 It is taken along the line X2-X2' Figure 8 A cross-sectional view of an example of an optical scanner 3 is shown in FIG. Figure 8 and Fig. 9 , the upper frame 32 of the optical frame 30 is omitted. Figure 8 and Fig. 9 , the heat flow channel 33 may include a heat conductor 33 extending from the deflector 310 toward the collimating lens 302. The thermal conductivity of the heat conductor 330 may be greater than the thermal conductivity of the optical frame 30. The heat conductor 330 may be made of, for example, a thin copper plate having high thermal conductivity. The heat conductor 330 may extend from the deflector 310 along the optical path 303. The heat conductor 330 may be supported by the lower frame 31, for example, by the bottom 305 of the lower frame 31. The heat conductor 330 may be in contact with at least one of the deflector 310 and the collimating lens 302. When the heat conductor 330 is not in direct contact with the deflector 310, one end of the heat conductor 330 may be located at a position adjacent to the deflector 310, for example, at the support plate 311. When the heat conductor 330 is not in direct contact with the collimating lens 302, the other end of the heat conductor 330 may be located at a position adjacent to the collimating lens 302.

[0053] In some examples, the thermal conductor 330 may be in contact with the deflector 310 and the collimating lens 302. The first end 331 of the thermal conductor 330 may be in contact with the support plate 311 of the deflector 310. For example, the first end 331 of the thermal conductor 330 may be in contact with the lower surface of the support plate 311, and may be coupled to the lower frame 31 together with the support plate 311 by means of screws S1 and S2. Therefore, a firm contact between the support plate 311 and the first end 331 of the thermal conductor 330 may be achieved. Since the support plate 311 is made of a metal having a high thermal conductivity and is supported by contacting with the circuit board 312, on which the motor 315 and the motor driving IC 313 generating a large amount of heat are mounted, the heat from the deflector 310 may be effectively transferred to the first end 331 of the thermal conductor 330 through the support plate 311. The second end 332 of the thermal conductor 330 may be in contact with the collimating lens 302. For example, the thermal conductor 330 extends from the first end 331 along the optical path 303 to below the collimating lens 302, and the collimating lens 302 may be in contact with the second end 332. The second end 332 of the thermal conductor 330 may be in contact with the non-optical region of the collimating lens 302 (i.e., the region through which the light L does not pass). The second end 332 of the thermal conductor 330 may have various shapes that can ensure as much contact area as possible with the non-optical region of the collimating lens 302. For example, the second end 332 of the thermal conductor 330 may have a shape that is consistent with the contour of the non-optical region of the collimating lens 302. Therefore, the heat from the deflector 310 may be transferred to the collimating lens 302 by conduction through the thermal conductor 330.

[0054] Although in Figure 8 and Fig. 9 Not shown, but reference Figures 1 to 3 The described convection channel 320 can be applied to Figure 8 and Fig. 9 . As the number of light emitting points in the light source 301 increases, the temperature of the light source 301 and the wavelength of the light increase when the light source 301 is driven. By combining the heat conductor 330 with the convection channel 320, the temperature difference between the light source 301 and the collimating lens 302 can be further reduced.

[0055] As an example method of reducing the temperature difference between the light source 301 and the collimator lens 302 , the heat generated from the light source 301 may be radiated to the outside of the optical scanner 3 . Fig.10 3 is a schematic diagram of an example of the optical scanner 3. Fig.10, the optical scanner 3 may include a heat sink 340 in contact with the light source 301, which dissipates the heat generated from the light source 301. The heat sink 340 may be made of a metal having a high thermal conductivity. For example, the heat sink 340 may include a hole 341, into which the light source 301 may be inserted. When the light source 301 is inserted into the hole 341, the outer surface of the light source 301 is in contact with the heat sink 340, and the heat generated from the light source 301 is transferred to the heat sink 340. The heat sink 340 is located outside the optical frame 30. For example, the heat sink 340 may be supported by a support frame 35 coupled to an outer portion of the lower frame 31 in the main scanning direction X. Therefore, the heat generated by the light source 301 may be dissipated to the outside, thereby preventing the temperature of the light source 301 from rising.

[0056] Although not shown in the figure, reference Figures 1 to 3 The described convection channel 320 can be applied to Fig.10 An example of an optical scanner 3 is shown in FIG. Figure 8 and Fig. 9 The described thermal conductor 330 can be applied to Fig.10 An example of an optical scanner 3 is shown in FIG. Figures 1 to 3 The convection channel 320 described in reference Figure 8 and Fig. 9 The described thermal conductor 330 can be applied to Fig.10 An example of the optical scanner 3 shown in . Therefore, the temperature difference between the light source 301 and the collimating lens 302 can be further reduced.

[0057] Fig.11 3 is a schematic diagram of an example of a printing device using an optical scanner 3. The printing device according to some examples is a monochrome printing device having a two-component developer including toner and a magnetic carrier. The color of the toner may be, for example, black. Fig.11 , the printing apparatus may include a photoconductor drum 1 and an optical scanner 3 that forms an electrostatic latent image by irradiating the photoconductor drum 1 with light.

[0058] The photoconductor drum 1 is an example of a photoconductor in which an electrostatic latent image is formed. The charging roller 27 is an example of a charger that charges the surface of the photoconductor drum 1 with a uniform surface electromotive force. The charging roller 27 rotates in contact with the photoconductor drum 1, and a charging bias is applied to the charging roller 27. The cleaning blade 28 cleans residual toner on the surface of the photoconductor drum 1 after, for example, a transfer process, as described below. Based on the rotation direction of the photoconductor drum 1, the static eliminator 29 can be set on the upstream side of the cleaning blade 28 to remove the residual potential on the photoconductor drum 1. For example, the static eliminator 29 can irradiate the surface of the photoconductor drum 1 with light. The optical scanner 3 forms an electrostatic latent image by irradiating the surface of the charged photoconductor drum 1 with light corresponding to the image information. Reference Figures 1 to 3 and Figures 8 to 10 The described optical scanner 3 can be used as the optical scanner 3 .

[0059] The developing device 2 may be a developing device including a photoconductive drum 1 and a developing roller 25. A developer is contained in the developing device 2. The developer is transported along a path inside the developing device 2, and in the process, the toner and the carrier are stirred together. The developing device 2 may include a stirring chamber 21 and a developing chamber 22. The developing roller 25 is installed in the developing chamber 22. The developing roller 25 is partially exposed to the outside of the developing chamber 22, and the exposed portion of the developing roller 25 faces the photoconductive drum 1. The stirring chamber 21 is separated from the developing chamber 22 by a partition wall 20. A first connecting portion and a second connecting portion (not shown) are respectively provided at opposite ends of the partition wall 20 in the longitudinal direction to connect the stirring chamber 21 and the developing chamber 22. A first conveying member 23 and a second conveying member 24 are respectively installed in the stirring chamber 21 and the developing chamber 22 to convey and circulate the developer inside the stirring chamber 21 and the developing chamber 22 along a path formed by the stirring chamber 21-first connecting portion-developing chamber 22-second connecting portion-stirring chamber 21. A portion of the developer conveyed in the developing chamber 22 adheres to the developing roller 25. The toner inside the developing chamber 22 adheres to the carrier by electrostatic force, and the carrier adheres to the surface of the developing roller 25 by the magnetic force of the developing roller 25. Therefore, a developing layer is formed on the surface of the developing roller 25. The developing roller 25 partially faces the photoconductor drum 1. The thickness of the developer attached to the surface of the developing roller 25 is adjusted by the adjusting member 26, and is conveyed to a developing area where the photoconductor drum 1 and the developing roller 25 face each other. According to the developing bias voltage applied between the developing roller 25 and the photoconductor drum 1, the toner is transferred from the developer layer on the developing roller 25 to the photoconductor drum 1, and a visible toner image is formed on the surface of the photoconductor drum 1.

[0060] The transfer roller 5 is an example of a transfer unit that transfers the toner image formed on the photoconductor drum 1 to the print medium P. The transfer roller 5 faces the photoconductor drum 1 and forms a transfer nip. A transfer bias is applied to the transfer roller 5, so that a transfer electric field is formed between the photoconductor drum 1 and the transfer roller 5. The toner image developed on the surface of the photoconductor drum 1 is transferred to the print medium P by the transfer electric field. The toner image transferred to the print medium P is attached to the print medium P by electrostatic force. The fuser 6 fuses the toner image to the print medium P by applying heat and pressure.

[0061] When the toner inside the developing device 2 is exhausted, the developer can be supplied from the developer container 4 to the developing device 2. A discharge port 41 is provided in the developer container 4. The developer container 4 may include a shutter 42 for selectively opening and closing the discharge port 41. The discharge port 41 and the developing device 2 may be connected by a developer supplying member 43. Under this configuration, the developer can be supplied from the developer container 4 to the developing device 2.

[0062] It should be understood that the various aspects, advantages and features described herein are not necessarily implemented or included in any one specific example, and the examples described herein should be considered descriptive. In fact, although various examples have been described and shown herein, it is obvious that other examples are also possible in terms of, for example, arrangement, replacement, combination and / or configuration. All corrections and modifications included in the scope of the subject matter disclosed herein are claimed. The description of each feature or aspect in each example should be considered to be applicable to other similar features or aspects in other examples. Although some examples are described with reference to the accompanying drawings, it should be noted that a person of ordinary skill in the art will consider various changes in form and detail within the scope of this disclosure.

Claims

1. An optical scanner, include: light source; A collimating lens, used to convert the light radiated from the light source into collimated light; a deflector located on a downstream side of the collimating lens, the deflector including a deflection mirror for deflecting the collimated light in a main scanning direction and a motor for rotating the deflection mirror; and A heat flow channel is used to transfer heat from the deflector to the collimating lens.

2. The optical scanner according to claim 1, comprising an optical frame for forming a receiving space to receive the light source, the collimating lens and the deflector, The optical frame includes a lower frame and an upper frame, the upper frame covers the upper portion of the lower frame, and in, The heat flow path includes a path for transferring heat from the deflector to the collimating lens.

3. An optical scanner as claimed in claim 2, wherein the channel is wider on the deflector side than on the collimating lens side.

4. The optical scanner of claim 2, wherein the channel is located above the optical path between the collimating lens and the deflector.

5. The optical scanner of claim 1, wherein the heat flow channel comprises a thermal conductor extending from the deflector toward the collimating lens.

6. The optical scanner according to claim 5, in: The deflector includes a support plate for supporting the motor; and The thermal conductor is in contact with at least one of the support plate and the collimating lens.

7. The optical scanner of claim 1, comprising a heat sink connected to the light source, the heat sink for dissipating heat from the light source.

8. The optical scanner of claim 7, comprising an optical frame for forming a receiving space to receive the light source, the collimating lens and the deflector, The optical frame includes a lower frame and an upper frame, the upper frame covers the upper portion of the lower frame, and in, The heat sink is located outside the optical frame.

9. The optical scanner of claim 1, wherein the collimating lens comprises a diffractive optical element (DOE) collimating lens.

10. An optical scanner, include: light source; A collimating lens, used for converting the light radiated by the light source into collimated light; a deflector, the deflector being located at a downstream side of the collimating lens and being used for deflecting the collimated light along a main scanning direction; as well as an optical frame for forming a space to accommodate the light source, the collimating lens and the deflector, Wherein, a region of the upper frame of the optical frame located between the deflector and the collimating lens partially protrudes upward to form a channel, and heat from the deflector is transferred to the collimating lens through the channel.

11. The optical scanner according to claim 10, in: The deflector comprises: A deflecting mirror for deflecting light; a motor for rotating the deflecting mirror; and a support plate for supporting the motor; and The optical scanner includes a heat conductor including one end connected to the support plate and extending toward the collimating lens to transfer the heat from the deflector to the collimating lens.

12. The optical scanner of claim 10, comprising a heat sink connected to the light source and located outside the optical frame, the heat sink for dissipating heat generated from the light source.

13. A printing device, include: Photoconductor; as well as an optical scanner for forming an electrostatic latent image by irradiating the photoconductor with light, the optical scanner comprising: light source; A collimating lens, used to convert the light radiated from the light source into collimated light; A deflector, the deflector being located at a downstream side of the collimating lens, the deflector comprising: a deflection mirror, for deflecting the collimated light along a main scanning direction; and a motor for rotating the deflecting mirror; and an optical frame for forming a space to accommodate the light source, the collimating lens and the deflector, Wherein, a region of the upper frame of the optical frame located between the deflector and the collimating lens partially protrudes upward to form a channel, and heat from the deflector is transferred to the collimating lens through the channel.

14. The printing device of claim 13, comprising a heat conductor extending from the deflector toward the collimating lens for transferring the heat from the deflector to the collimating lens.

15. The printing apparatus of claim 13, comprising a heat sink connected to the light source and located outside the optical frame, the heat sink for dissipating heat generated from the light source.

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