JP3570597B2 - Vibration control device for copier - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vibration damping device for a copying machine that scans a document using a scanner device.
[0002]
[Prior art]
In recent copiers, a guide rod is arranged in the scanning direction below a platen glass, and one end of a first scanner and a second scanner are slidably attached to the guide rod, and each scanner is reciprocally scanned along the guide rod. A so-called platen-fixed type document reading device that irradiates a photoconductor drum with a light image from a document placed on a platen glass through a lens and thereby performs copying by using the lens is often used. . The scanner driving method of the above-described document reading apparatus includes a one-side driving method and a two-side driving method. The one-side drive system is a system in which a wire or a timing belt is disposed near a guide rod, and one end of a scanner is fixed to the guide rod to perform reciprocal scanning. In this method, compared with a double-sided driving method in which both ends of the scanner are fixed to a wire or a timing belt, the driving system requires only half, so that the whole unit can be downsized and the wiring of the wire or the timing belt can be simplified. is there. However, as a structural defect, there is a problem that the impact at the time of starting or stopping the scanner amplifies the vibration at the free end side, and deteriorates the quality of the formed image.
[0003]
As a conventional technique for solving the above-mentioned problems, as described in Japanese Utility Model Laid-Open No. 3-105842, the first and second mirror units of the optical system of a copying machine are mounted on the same guide shaft. First and second slide members are provided for sliding along the first and second slide members, and one of the slide members is provided with a fitting concave portion, and the other slide member is provided with a fitting convex portion which is fitted in the above-mentioned fitting concave portion so as to be tightly fitted therein. There is known a cushion absorber for an optical system of a copying machine, which functions as a kind of air damper when a fitting concave portion and a fitting convex portion are fitted to each other to improve the vibration at the time of stopping and the accuracy of a stopping position. However, the above-mentioned invention has a problem that the structure is complicated and the cost is high.
[0004]
Further, as described in Japanese Utility Model Laid-Open Publication No. 3-56945, in an optical scanning device that reciprocates and scans an original surface by exposure, a leaf spring and an elastic rubber are provided between a holding body and an apparatus main body. 2. Description of the Related Art There is known a scanning optical device for preventing a collision between a holder and an apparatus main body when a system returns to a home position. However, the above-described invention is not intended for the scanner driving method, particularly for the one-sided driving method. When the scanner is used for the one-sided driving method, vibrations in a direction perpendicular to the moving direction of the optical system are hardly absorbed. There is.
[0005]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems. In a copying machine having a scanner of one end supporting type, one end of the scanner is supported by a guide rod and the other end is a free end, In this position, a vibration damping device for a copying machine that can absorb the vibration of the scanner, can be installed in the body of the copying machine in a small space, and can achieve a large vibration suppression effect at a small cost. The purpose is to provide.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, an invention according to claim 1 is a copying machine that scans a document while performing slit exposure with a first scanner traveling at a speed V and a second scanner traveling at a speed V / 2 to form an image. in machine, the first scanner and the second scanner is supported at one end on the same guide rod and the other end is a free end, at least the first scanner, the free at the free end opposite to the position at the home position of its contacting the end, characterized in that a resilient member Ru pressed against the guide rod direction.
[0007]
According to a second aspect of the present invention, in order to solve the above-mentioned problem, in the first aspect of the present invention, a material of the elastic body is a foam material, and a polyester film is attached to a surface of the elastic body.
[0008]
According to a third aspect of the present invention, in order to solve the above-mentioned problem, in the first aspect of the present invention, the elastic body is a leaf spring material.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a vibration damping device for a copying machine according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing an example of a copying machine having an optical unit of a one-side belt drive system. A first scanner 1 and a second scanner 2 that scan an original while performing slit exposure have a first scanner slide member 3 and a second scanner slide member 4 attached to one end, respectively. The first scanner slide member 3 has a cylindrical shape, and a center hole is slidably inserted into and supported by the guide rod 5. The second scanner slide member 4 is a flat U-shaped member formed by bending both ends of a long plate at right angles, and has a hole at the center of the bent portions 6 at both ends. It is slidably inserted into and supported by the guide rod 5. The bent portions 6, 6 of the second scanner slide member 4 are located on both sides of the first scanner slide member 3 with a sufficient dimensional allowance. The scanner 2 moves between the bent portions 6 at both ends.
[0010]
Rotational force of a motor (not shown) is transmitted to the first scanner 1 and the second scanner 2 via wires or belts wound on a plurality of pulleys (not shown), and the first scanner 1 and the second scanner 2 It is possible to reciprocate along. As is well known, the second scanner 2 can reciprocate along the guide rod 5 at half the speed of the first scanner 1.
[0011]
FIG. 2 is a side view showing an example of a scanning optical system used in the copying machine according to the present invention. A first scanner 1 and a second scanner 2 are arranged below a contact glass 15 on which a document 16 is placed. The first scanner 1 has an exposure lamp 11 and a first mirror 12, and the exposure lamp 11 and the first mirror 12 can be moved integrally. The first mirror 12 reflects light reflected from the document 16 in the horizontal direction. Further, the second scanner 2 has a second mirror 13 and a third mirror 14, and these second and third mirrors 13, 14 are integrally movable. The second and third mirrors 13 and 14 are obliquely arranged so that their reflection surfaces are at right angles to each other, and fold the reflected light from the first mirror 12 in the horizontal direction. Both the first scanner 1 and the second scanner 2 receive the rotational force of the motor via a wire rope or a belt, and move while sliding along the guide rod 5. At this time, in order to keep the optical distance from the original 16 being exposed to the photosensitive drum 25 constant, the first scanner 1 is moved by a wire rope or a wire rope so as to move at twice the speed of the second scanner 2. The belt is hung on a plurality of pulleys (not shown).
[0012]
The illumination light emitted from the exposure lamp 11 is reflected by a document 16 placed on a contact glass 15, and the reflected light is reflected by a first mirror 12, a second mirror 13, and a third mirror 14 in that order, and the lens 17 The light is reflected by the fourth mirror 18, the fifth mirror 19, and the sixth mirror 20 in this order, passes through the dustproof filter 21, and projects an original image on the photosensitive drum 25. The scanning control of the scanning optical system is performed by feedback control based on a pulse corresponding to the scanning distance output from an encoder or the like built in the motor. The fourth, fifth, and sixth mirrors 18, 19, and 20 are fixed.
[0013]
Here, the clearance between the inner diameter of the first scanner slide member 3 or the second scanner slide member 4 of the guide rod 5 and the outer diameter of the guide rod 5 is a very important factor. If the clearance is too large, the vibration at the time of activation of the scanner is amplified, and the free end 10 of the first scanner 1 vibrates, thereby deteriorating the quality particularly at the leading end of the image. On the other hand, if the clearance is too small, the sliding resistance between the guide rod 5 and the scanner increases, so that the scanners 1 and 2 are locked, which deteriorates the quality of a part or the whole image and also makes the scanning impossible. There is also.
[0014]
In consideration of the use environment of the copying machine, the difference between the maximum temperature and the minimum temperature is about 40 degrees, and since the first scanner 1 has the exposure lamp 11, the first scanner slide member 3 is particularly It is more easily heated and undergoes considerable thermal expansion.
[0015]
For example, when the material of the guide rod 5 is polyoxymethylene (POM) plastic, when the thermal contraction and thermal expansion at an inner diameter of 16 mm are calculated, the inner diameter Φ after the thermal expansion becomes
Φ = 16 × (1 + αΔT)
Substituting α = 10 × 10 ⁻⁵ (1 / K) into this equation, the guide rod 5 shrinks by 0.024 mm under an environment of 10 ° C., and expands by 0.024 mm under an environment of 60 ° C. It expands by 056 mm. However, this is the case where the heat shrinkage at room temperature is set to zero.
[0016]
In the above case, when the clearance is increased by 0.05 mm with respect to the normal temperature, the waveform indicating the vibration at the time of starting the scanner at the free end 10 of the first scanner 1 is as shown in FIG. FIG. 3 shows a waveform indicating the vibration at the time of starting the scanner at the free end 10 of FIG. The horizontal axis indicates the lapse of time from the start of the scanner, and the vertical axis indicates the amount of electrical conversion of the vibration amount at the free end 10 of the first scanner 1. As is clear from the figure, the vibration before the clearance between the inner diameter of the first scanner slide member 3 and the outer diameter of the guide rod 5 increases (FIG. 3) is smaller than the vibration after the clearance increase (FIG. 4). It can be seen that if the clearance is too large, the vibration at the free end 10 when the scanner is activated is amplified, and the quality particularly at the leading end of the image is reduced.
[0017]
As described above, it is difficult to set the clearance between the inner diameters of the first and second scanner slide members 3 and 4 and the outer diameter of the guide rod 5, and it is necessary to select a material having a small thermal expansion even when selecting a material. As a result, it has conventionally been necessary to produce expensive materials with high precision dimensions. Further, even when a component made of an expensive material with high precision dimensions is used in a high temperature state, the operation performance of the scanner is reduced, which causes a deterioration in image quality.
[0018]
In order to suppress the vibration at the free end 10 of the scanner when the scanner is started as described above, an elastic body 7 is attached to the side surface of the optical unit frame 9 on the free end 10 side of the first scanner 1 as shown in FIG. The first scanner 1 is brought into contact with the first scanner 1 at the home position. In the present embodiment, an example is shown in which a foam material made of foamed polyethylene is used as the elastic body 7 and a polyester film 8 is attached to the surface thereof.
[0019]
FIG. 5 shows an example in which foamed polyethylene 21 is used as the elastic body 7. One end of the polyester film 8 is adhered to one surface of the rectangular parallelepiped foamed polyethylene 21 with a double-sided tape or the like, and as shown in FIG. Is attached with double-sided tape. The middle portion 24 of the polyester film 8 is inclined, and the rear end of the polyester film 8 is attached to the side surface of the optical unit frame 9 with a double-sided tape or the like.
[0020]
By making the distance between the free end 10 side of the first scanner 1 and the side surface of the optical unit frame 9 slightly smaller than the thickness of the foamed polyethylene 21, near the home position, the first scanner 1 Since the scanner moves while receiving a compressive force due to the elastic force, a good vibration damping effect can be obtained when the scanner is started, and the image is not disturbed. The polyester film 8 serves to reduce the frictional resistance between the free end 10 of the first scanner 1 and the elastic body 7 when the first scanner 1 returns to the home position. It is provided to reduce wear and fatigue.
[0021]
FIG. 6 is a perspective view showing a leaf spring 23 as another example of the elastic body 7. As described above, when the elastic body 7 is the leaf spring 23, it is possible to further increase the durability and the life margin compared to the case where the polyester film 8 is attached to the surface of the foamed polyethylene 21. .
[0022]
FIG. 7 shows that the inner diameter of the center hole of the both-end bent portion 6 of the first scanner slide member 4 is increased, the clearance is increased by 0.05 mm with respect to the room temperature as in the case of FIG. 6 is a waveform showing vibration at the time of starting the scanner at the free end 10 of the first scanner 1 when the body 7 is mounted. When the elastic body 7 is used in this manner, the vibration at the time of starting the scanner at the free end 10 of the first scanner 1 is clearly reduced as compared with the case where the clearance is increased without applying the elastic body 7 (FIG. 4). However, it can be seen that there is almost no difference from FIG. 3 showing the vibration waveform before the clearance is increased. That is, it is shown that by applying the elastic body 7 as in the present invention to a copying machine, a sufficient vibration damping effect can be obtained even if the clearance between the scanner slide member and the guide rod increases. The present invention can provide a copying machine that does not lower the scanning performance even when the environment is deteriorated due to a temperature change or the like by adding inexpensive parts to the copying machine.
[0023]
The present invention is not limited to the above-described embodiment. For example, as the elastic body 7, a foamed material obtained by foaming a synthetic resin other than foamed polyethylene, or a material formed of a synthetic resin in a non-foamed state is used. Alternatively, the surface of the elastic body 7 may be covered with a synthetic resin film other than the polyester film. Further, the vibration damping device of the free end 10 of the first scanner 1 has been described. However, the vibration damping device of the second scanner 2 having the same configuration can be used. It is also possible to use both types of vibration damping devices.
[0024]
【The invention's effect】
According to the first aspect of the present invention, in the copying machine, the original is scanned by the first scanner traveling at the speed V and the second scanner traveling at the speed V / 2 while performing slit exposure to form an image. 1 scanner and the second scanner is supported at one end on the same guide rod and the other end is a free end, in contact with at least a first scanner, this free end at the free end opposite to the position at the home position of its above due to the provision of the elastic body Ru pressed against the guide rod direction, can absorb the vibrations of the scanner, it is possible to prevent deterioration of image quality.
[0025]
According to the second aspect of the present invention, in the first aspect of the present invention, since the material of the elastic body is a foam material and a polyester film is attached to the surface thereof, the vibration of the scanner can be absorbed, and furthermore, it is possible to reduce the vibration. It can be easily incorporated into the main body of the copying machine in a small space, and a large vibration damping effect can be achieved at a small cost.
[0026]
According to the third aspect of the present invention, in the first aspect of the present invention, since the elastic body is a leaf spring material, the vibration of the scanner can be absorbed, and the space can be saved in the main body of the copying machine. It can be incorporated, and a large damping effect can be achieved at a small cost.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a vibration damping device for a copying machine according to the present invention.
FIG. 2 is a side view showing an embodiment of a scanning optical system of the copying machine according to the present invention.
FIG. 3 is a graph showing an example of a vibration waveform at a free end of a first scanner.
FIG. 4 is another graph showing an example of a vibration waveform at a free end of the first scanner.
FIG. 5 is a perspective view showing an example of an elastic body that can be used in the vibration damping device of the copying machine according to the present invention.
FIG. 6 is a perspective view showing another example of an elastic body that can be used in a vibration damping device of a copying machine according to the present invention.
FIG. 7 is a graph showing an example of a vibration waveform at the free end of the first scanner when the vibration damping device of the copying machine according to the present invention is used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st scanner 2 2nd scanner 5 Guide rod 7 Elastic body 8 Polyester film 10 Free end 16 Document 21 Foamed polyethylene 23 Leaf spring material

Claims (3)

In a copying machine that scans an original with a first scanner that runs at a speed V and a second scanner that runs at a speed V / 2 while performing slit exposure while forming an image, the first scanner and the second scanner have one end identical. supported by the guide rod, the other end is a free end, provided with at least a first scanner, in contact with the free end at the free end opposite to the position at the home position of its elastic body Ru pressed against the guide rod direction A vibration damping device for a copying machine. 2. A vibration damping device for a copying machine according to claim 1, wherein said elastic body is made of a foam material, and a polyester film is attached to a surface of said foam body. 2. A vibration damping device for a copying machine according to claim 1, wherein said elastic body is a leaf spring material.

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