JP2000171917A - Scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce the torque of a motor for driving a slider by sufficiently cooling a lighting driver by means of a small and lightweight heat radiation member. SOLUTION: This scanner is so constituted that an exposure lamp 50 for exposing a document D and the lighting driver 64 for driving the lighting thereof and a scanning optical element 51 for picking up the reflected light from the document D and directing the light toward a prescribed light receiving object, such as a CCD or photoreceptor, are included in the slider 31. The heat radiation member 52 of the lighting driver 64 is projected to the outside of the slider 31, by which the slider 31 is brought into contact with the atmosphere outside the slider and is easily subjected to heat radiation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner, and more particularly, to a scanner which scans an image of a document with a copying machine or an image reading device and uses the scanning light for copying, image recording, and image reading.

[0002]

2. Description of the Related Art A scanner has a scanning optical element such as a scanning mirror for picking up reflected light from the original and directing the reflected light from the original to a predetermined light receiving object, and the scanner is stopped by the movement of the slider. While exposing and illuminating the image with an exposure lamp, the reflected light from the document at each moving position is picked up while the scanning light is being picked up, and the scanning light is to be received, for example, a photoreceptor or recording medium for copying or other image formation, or image reading. The image formation or the image reading is performed toward the optical sensor for use.

Conventionally, fluorescent lamps have been used as exposure lamps,
In order to obtain high-luminance light emission, inverter driving is performed with an attenuation waveform. In this case, however, heat generation of the driver is a significant problem. For example, a heat dissipating member is provided in a lighting driver for driving the inverter. Cooling is performed, and a relatively large heat radiating member is used for the size of the lighting driver for sufficient cooling.

On the other hand, since the inverter drive is driven at a high frequency and is greatly affected by noise, it is preferable to shorten the harness for connecting to the exposure lamp. US Patent 495
No. 9737 proposes mounting a lighting drive device on a slider. According to this, the influence of noise can be reduced by shortening the harness.

[0005]

The present inventors have attempted to use the above-mentioned conventional lighting driver mounted on a slider. However, the lighting driver has a large weight due to having the large heat dissipating member, and a large torque motor is required to drive the slider having the large heat dissipation member with a predetermined accuracy. This leads to an increase in power consumption.

An object of the present invention is to provide a scanner capable of sufficiently cooling a lighting driver with a small and lightweight heat radiating member and reducing the torque of a motor for driving a slider.

[0007]

In order to achieve the above object, a scanner according to the present invention comprises an exposure lamp for exposing a document, a lighting driver for driving the same, and a light receiving object for picking up reflected light from the document. One of the features of the present invention is that the slider has a scanning optical element directed toward the slider and a heat radiation member of the lighting driver is provided so as to protrude outside the slider.

When the heat radiating member projects outside the slider as described above, the heat radiating member easily touches the atmosphere outside the slider and easily radiates heat. In addition, each time the slider moves and scans the original with the exposure lamp and the scanning optical element, the slider is moved. Since the outside atmosphere of the slider acts as a cooling airflow due to relative movement with the outside atmosphere, the heat of the cooling member is easily taken away, so the lighting driver can be sufficiently cooled by a small and lightweight heat dissipation member, and the lighting including the heat dissipation member The weight of the driver can be reduced, and the torque of the motor required to drive the scanner with predetermined accuracy can be reduced.

If the protrusion of the heat radiating member to the outside of the slider is a fin, heat radiation to the atmosphere outside the slider is high, and the heat radiating member can be made thinner and smaller, which is effective for reducing the driving torque of the slider. . When the fin is parallel to the moving direction of the slider, the relative movement direction between the fin and the atmosphere outside the slider when the slider moves is in the direction along the fin. Since it is in good contact with it without being disturbed, the heat is more easily taken away by the atmosphere outside the slider, the heat dissipation is improved, and the size of the heat dissipation member can be further reduced.

If the surface of the heat radiating member is black, even if it protrudes from the slider, it is possible to reduce the generation of irregularly reflected light in the optical path of the imaging optical system by reflecting scattered light and the like. It is possible to reduce the deterioration of the image quality. In particular, if the heat radiating member is located behind the scanning mirror, which is a scanning optical element, the heat radiating member is located outside the optical path of the imaging optical system and is separated from this optical path by the scanning optical element. The possibility of generating irregularly reflected light in the optical path can be almost eliminated.

Further objects and features of the present invention will become apparent from the following detailed description and drawings. Each feature of the present invention can be used alone or in various combinations in combination as far as possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to FIGS.

This embodiment is an example of a scanner for reading an image of a document in a digital copying machine. However, the present invention is not limited to this, and is generally applicable to scanners for reading an image with an analog copying machine, or for recording an image reading data on a recording medium or outputting the image data to another device alone. Can be.

As shown in FIG. 1, a digital copying machine according to the present embodiment has a photosensitive drum 1 substantially at the center of an apparatus main body 100.
Is installed so as to be driven to rotate in the direction of arrow a. Around the photosensitive drum 1, a charging device 2, a laser scanning optical system 3, a developing device 4, a transfer device 5, a paper separating device 6, and a residual toner on the photosensitive drum 1 for forming an image by an electrophotographic process. A cleaning device 7 for removing the residual charge, and an eraser 8 for removing the residual charge.

Since the principle of the electrophotographic process is well known, a detailed description will be omitted and a brief description will be given. The laser scanning optical system 3 receives an image signal of the document D read by the image reading device 30, outputs a laser beam modulated in accordance with the image signal, and outputs a laser beam modulated by the charging device 2 of the photosensitive drum 1. Is subjected to image exposure. As a result, an electrostatic latent image corresponding to the image of the document D is formed on the photosensitive drum 1. The electrostatic latent image is then developed with toner and visualized, and is transferred to a sheet conveyed by the transfer device 5 at a transfer portion between the transfer device 5 and the photosensitive drum 1.
Copied. The surface of the photoreceptor drum 1 after transfer is removed by a cleaning device 7 to remove residual toner, an eraser 8 is used to remove residual charge, and charged again by the charging device 2 to repeat image formation. The paper after copying by transfer is sent to a fixing device 18 by a conveyor belt 17 to apply heat, pressure,
Alternatively, the fixing process is performed by both of them, and the sheet is discharged to the discharge tray 20 outside the apparatus main body 100 by the discharge roller 19 after the fixing.

The apparatus main body 100 feeds the paper to be conveyed to the transfer section. It is provided together with the rollers 11 and 12. Sheets in the sheet cassettes 9 and 10 according to the selection of the sheet size are selectively fed one by one by one rotation of the corresponding sheet feeding rollers 11 and 12. The fed sheet is temporarily stopped by the timing roller 16, the leading end thereof is aligned with the nip, the skew is corrected, and the rotation of the timing roller 16 is restarted to feed the sheet and the sheet and the photosensitive drum 1. Synchronized with the visual image, the visual image is transferred and copied at a predetermined position on the sheet.

The apparatus main body 100 is mounted on a sheet feeding / conveying apparatus 200, and the sheets in the sheet feeding cassettes 21 to 23 held by the sheet feeding / conveying apparatus 200 are also supplied to sheet feeding rollers according to the selection of the sheet size. The light is sent out by one of the rotation drives 13 to 15 and is conveyed to the transfer section to be used for transferring a visual image.

The basic configuration of the image reading device 30 is shown in FIG.
As shown in FIG. 2, the first reciprocating movement in the direction of arrow b
, And a second slider 32.
The first slider 31 has an exposure lamp 50 for illuminating the document D as shown in FIGS. 1 and 3, and a CCD for reading an image which is a light receiving object by picking up reflected light from the document D at each moving position through the slit 54. The original D is scanned by a scanner provided with a scanning mirror 51 serving as a scanning optical element directed to the line sensor 25, and the scanning light of the original D is sequentially formed on the CCD line sensor 25.

Thus, the CCD line sensor 25 converts the image information of the document D to be imaged into an electric signal and sequentially inputs the electric signal to the laser scanning optical system 3. The laser scanning optical system 3 outputs laser light modulated according to the sequentially input image signal. This output is deflected by a scanning optical element such as a polygon mirror in the direction of the rotation axis of the photosensitive drum 1, and the image data for one line of the CCD line sensor 25 is shifted in the direction of the rotation axis on the photosensitive drum 1. The main scanning for writing is repeated. The rotation of the photosensitive drum 1 in the direction of the arrow a at the same time becomes the sub-scanning, the image of the document D is exposed on the surface of the photosensitive drum 1, and the corresponding electrostatic latent image is formed.

As shown in FIG. 1, the second slider 32 has a pair of return mirrors 27 and 28 for returning the scanning light from the scanning mirror 51 to the image forming lens 24 in a reverse direction. It is driven at half the moving speed V to keep the conjugate length of the imaging lens 24 constant. As shown in FIG. 2, each of the first and second sliders 31 and 32 has one end fitted to the slide shaft 33 and the other end received by the slide rail 34 so that the first and second sliders 31 and 32 are in a horizontal state as indicated by an arrow b. It is freely movable in the direction. The first and second sliders 31, 32 are driven and moved by one stepping motor M1.

The stepping motor M1 drives the pulleys 35, 36,
Drive pulley 37 driven via timing belt 47
The wire 38 wound in the middle is used. Drive pulley 37
Is located in the movement area of the first and second sliders 31 and 32, and the wire 38 has a pair of return pulleys with one end 38a of the wire 38 located outside the movement area of the first and second sliders 31 and 32. 39 and 40, the first slider 31 is folded around the return pulley 39 on the side of the first slider 31 and then folded back.
The side 8b is looped around the return pulley 40 on the second slider 32 side. Return pulley 3
The one end 38a side of the wire 38 turned back at 9 is fixed to the first slider 31 in the middle with a pin 61 or the like,
It is further extended and wound around one of the movable pulleys 41a, 41b provided at one end of the second slider 32 and rotatable relative to each other. And so on. The other end 38b of the wire 38 folded back by the return pulley 40 is wound halfway around the other movable pulley 41b at the end of the second slider 32 and fixed to a fixed portion on the side of the return pulley 40 with a pin 63 or the like. I'm wearing

As a result, the first slider 31 is moved at the same speed V as it is driven and moved by the stepping motor M1. On the other hand, the second slider 32 is moved by the wire 38 to the movable pulleys 41a, 41b.
Moves at the speed of V / 2 while rotating, and the moving speed becomes V / 2. The wire 38
A spring is provided between one end 38a and the other end 38b of the first and second portions and a fixing portion to the fixed portion, and the first and second sliders 31,
It is preferable to provide a buffer for simultaneous driving of 32.
When the first slider 31 is equipped with a CCD line sensor 25 or the like as a light receiving target for the scanner, an optical element for picking up reflected light from the document D is a selfoc lens or the like, and the scanning light is a CCD line sensor 25. It can also be configured to form an image directly on the
The slider 32 and the imaging lens 24 are unnecessary.

Exposure lamp 5 provided on first slider 31
Numeral 0 denotes a fluorescent lamp, which uses a lighting driver 64 ((a) in FIGS. 1, 3, and 4) that is driven by an inverter with an attenuation waveform in order to obtain high-luminance light emission. On the other hand, the inverter drive becomes a high-frequency drive and has a large influence of noise.
It is preferable to shorten a harness (not shown) for connection with the cable. Therefore, the lighting driver 64 is mounted on the first slider 31 as shown in FIGS. 1 and 3, and the exposure lamp 50 and the lighting driver 64 come close to each other, the harness connecting the both becomes short, and the influence of noise is reduced. Is to be reduced.

On the other hand, the lighting driver 64 that drives the exposure lamp 50 with an inverter with an attenuated waveform is problematic because the driver of the exposure lamp 50 generates a large amount of heat. When the weight increases, the first
There is also a problem that the weight of the slider 31 increases and the required torque of the stepping motor M1 for driving the slider 31 increases.

Therefore, in this embodiment, the stepping motor for driving the first slider 31 by sufficiently cooling the lighting driver 64 by the small and lightweight heat dissipating member 52 as shown in FIGS. The torque required for M1 can be reduced. Specifically, as shown in FIGS. 1 and 3 to 7, the heat radiating member 52 of the lighting driver 64 is provided so as to protrude out of the first slider 31. When the heat radiating member 52 projects outside the first slider 31, the heat radiating member 52 easily touches the outside atmosphere of the slider at the projecting portion 53 and radiates heat. Since the outside atmosphere of the slider acts as a cooling flow due to relative movement with respect to the outside atmosphere and heat is easily taken away, the lighting driver 64 can be sufficiently cooled by the small and lightweight heat dissipation member 52, and the lighting drive including the heat dissipation member 52 And the required torque of the stepping motor M1 for driving the first slider 31 as a scanner can be reduced.

Therefore, it is possible to reduce the size, cost and power consumption of the motor. The heat dissipating member 52 is preferably made of a material having good thermal conductivity, and the aluminum type is particularly preferable because it is lightweight. However, the present invention is not limited to this, and its material and form can be freely selected. In addition to the case where the atmosphere outside the slide is a cooling air flow, the heat radiation member
The heat dissipating effect is greatly increased.

In the embodiment shown in FIG. 1 to FIG.
As shown in FIGS. 4 (a) and 4 (b), the projections 53 of the second slider 31 outside the first slider 31 form a group of fins 53a. As a result, heat radiation to the atmosphere outside the slider is enhanced, and the heat radiation member 52 can be made thinner and smaller by that much, which is effective in reducing the driving torque of the first slider 31. When the fins 53a are parallel to the moving direction b of the first slider 31 as shown in FIG. 4A, the fins 53a when the first slider 31 moves are shown.
Since the relative movement direction between the fin 53a and the outside atmosphere of the slider is along the fin 53a, the wide flat portion of the fin 53a efficiently contacts the outside atmosphere of the slider without disturbing the outside atmosphere of the slider. The atmosphere is more likely to be deprived and the heat dissipation is improved.
2 can be further reduced in size. This is because even if the protrusion 53 does not take the form of the fin 53a, the first slider 3
In the case of the one formed long in the moving direction of 1, the same operation and effect is exhibited.

The surface of the heat radiating member 52 is black. Thus, even if the heat radiating member 52 protrudes from the first slider 31, it is possible to reduce generation of irregularly reflected light in the optical path of the imaging optical system by the imaging lens 24 and the like by reflecting scattered light and the like. In addition, it is possible to reduce the deterioration of image quality due to irregularly reflected light. In particular, when the heat radiating member 52 is installed behind the scanning mirror 51 as a scanning optical element as shown in FIGS. 1 and 3, the heat radiating member 52 is located outside the optical path of the imaging optical system. And scanning mirror 51
Therefore, the possibility that the heat radiation member 52 generates irregularly reflected light in the optical path can be almost eliminated.

In the embodiment shown in FIG.
2 is a plate member applied to the lower surface of the lighting driver 64 as shown in FIGS.
Are formed so as to form a protruding portion 53 integrally protruding downward. Each of the fins 53a may be post-mounted by welding, brazing, bonding, screwing, pinning, or the like. However, it is preferable to use an integrally molded product such as extrusion since the structure is simple and the cost is low.

In the embodiment shown in FIG. 5, the projecting portion 53 of the heat radiating member 52 made of a plate member is formed by fins 53a formed by bending both sides and fins 53a cut and raised therebetween. This does not complicate the structure. In the embodiment shown in FIG. 6, the radiating members 52 composed of plate members are attached to both side surfaces of the lighting driver 64 and extended downward to form the fins 53a to form the projecting portions 53, and the radiating members on both sides are formed. By connecting the plate 52 and the plate-shaped heat radiating member 52 applied to the lower surface of the lighting driver 64 at both ends thereof, the heat of the lighting driver 64 can be radiated and cooled. The lower surface of the heat radiating member 52 applied to the lower surface of the lighting driver 64 is also integrally formed as shown by a virtual line,
Or cut-and-raised or retrofitted fins 53a
May be provided to increase the number of fins 53a. In the embodiment shown in FIG. 7, the projecting portion 53 has the simplest shape, and the plate-shaped heat dissipating member 53 bonded to the lower surface of the lighting driver 64 is bent into an L shape to form the fin 53a. Is formed. Further, as shown by the imaginary line, a projection 53 formed by bending both sides to form two fins 53a.
It may be. In short, the shape and number of the protruding portions 53 may be variously designed according to the required heat radiation degree.

The projecting portion 53 of the heat radiating member 52 may project from any side of the first slider 31 to the outside. However, when projecting downward, the surrounding dead space can be effectively used, and the projecting portion can be projected over a wider range. Therefore, the lighting driver 64 mounted on the first slider 31 is easily cooled.

[0032]

According to the scanner of the present invention, the protrusion of the heat radiating member to the outside of the slider makes it easy to radiate heat by touching the atmosphere outside the slider. In addition, each time the slider moves, the atmosphere outside the slider acts as a cooling airflow to release heat. The motor required to heat the members easily, and to sufficiently cool the lighting driver with a small and lightweight heat dissipating member, reduce the weight of the lighting driver including the heat dissipating member, and drive the scanner with predetermined accuracy Therefore, the motor can be reduced in size, cost and power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a digital copying machine employing a scanner according to a representative embodiment of the present invention.

FIG. 2 is a perspective view showing a scanning optical system of the copying machine shown in FIG.

FIG. 3 is a cross-sectional view of the scanning optical system of FIG.

4A and 4B show the scanning optical system of FIG. 2, in which FIG. 4A is a bottom view mainly showing the first slider, and FIG. 4B shows one embodiment of a heat dissipating member provided in the first slider. FIG.

FIG. 5 is a cross sectional view showing another embodiment of the heat radiating member.

FIG. 6 is a perspective view showing another embodiment of the heat radiation member.

FIG. 7 is a side view showing another embodiment of the heat dissipating member.

[Explanation of symbols]

 D Document 3 Laser Scanning Optical System 24 Imaging Lens 25 CCD Line Sensor 30 Image Reader 31 First Slider 50 Exposure Lamp 51 Scanning Mirror 52 Heat Dissipating Member 53 Projection 53a Fin 64 Lighting Driver

Claims (5)

[Claims] 1. A scanner having an exposure lamp for exposing a document, a lighting driver for lighting and driving the same, and a scanning optical element for picking up reflected light from the document and directing the light to a light receiving object on a slider. A scanner wherein a member is provided so as to protrude out of a slider. 2. The scanner according to claim 1, wherein the protrusion of the heat radiating member outside the slider is a fin. 3. The scanner according to claim 1, wherein the protrusion is parallel to a moving direction of the slider. 4. The scanner according to claim 1, wherein the heat radiating member is black. 5. The scanner according to claim 1, wherein the heat radiating member is provided on a back of a scanning mirror as a scanning optical element.