JPH0829889A - Damping device for moving optical system - Google Patents

Abstract

PURPOSE:To obtain a damping device for a moving optical system in a copying machine capable of securing stable traveling over a long term. CONSTITUTION:The moving optical system of a one-side driving system is equipped with traveling bodies 1 and 2 where a light source illuminating an original to be read and an optical member such as a mirror reflecting the reflected light from the original or an image sensor, etc., are mounted, a guiding member 4 disposed on both sides of the traveling bodies 1 and 2 and guiding the traveling bodies 1 and 2 to freely move back and forth in a subscanning direction, and a driving means coupled with only one side of the traveling bodies 1 and 2. The optical system is provided with a movable pulley 26 on the driven side of the traveling bodies 1 and 2 and a wire 40 extended in the subscanning direction by winding its one part round the movable pulley 26 at least by more than one round and stretched to impart component force in the direction of the guiding member 4 to the movable pulley 26, and at least one end of the wire 40 is locked on device main bodies 29 and 32 through an elastic member 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention exposes and scans an original by, for example, first and second optical systems that move at a speed ratio of 2: 1 to sequentially form an image on a light receiving portion such as a photoconductor and a CCD image sensor. The present invention relates to a vibration damping device for a moving optical system in a copying machine, a document image reading device, or the like.

[0002]

2. Description of the Related Art Generally, in this type of copying machine, digital scanner, etc., for example, a first optical system including a lamp and a first mirror and a second optical system including a second mirror are movably provided to expose a document. At the time of scanning, the first optical system and the second optical system are moved in the same direction at a speed relationship of 2: 1 so that the original image is formed on the photoconductor or the like while keeping the optical path length constant. More specifically, as shown in Japanese Patent Laid-Open No. 55-121430, a drive-side guide shaft and a driven-side guide shaft are provided on both sides of the first and second optical systems, and
The optical system is driven by a wire provided on the drive side guide shaft side. The first and second optical systems are slidably supported on the drive-side guide shaft by two slide bearings, respectively, and on the driven-side guide shaft, one rolling bearing (roller bearing or ball bearing). Supported by bearings).

Such a one-sided drive type moving optical system is
For example, it is configured as shown in FIG. First, a first optical system 1 on which a lamp (not shown) and a first mirror (not shown) are mounted is provided. Further, a second optical system 2 having a second mirror (not shown) mounted thereon is provided. A drive-side guide shaft 3 (guide member) and a driven-side guide shaft 4 (guide member) that guide the movement of the first and second optical systems 1 and 2 (running body) are provided in parallel on both sides. There is. Here, the drive side guide shaft 3 has a circular cross section, and one side of the first optical system 1 is supported by two slide bearings 5a and 5b slidably fitted to the drive side guide shaft 3. ing. Similarly, the one side of the second optical system 2 also has two slide bearings 6a, 6a slidably fitted on the drive side guide shaft 3.
supported by b. On the other hand, the driven guide shaft 4 is a plate having a square cross section, and the other sides of the first, second optical systems 1 and 2 are slid on the driven guide shaft 4 by one slide bearing 7, 8. It is movably supported (it may be rotatably supported by rolling bearings).

A first wire 9 is provided on the drive side of the first and second optical systems 1 and 2, that is, on the drive side guide shaft 3 side. For this reason, the first drive pulley 12 is provided on the drive shaft 11 of the motor 10 (driving means) which is a forward / reverse step motor as a drive source, and the first wire 9 is wound around the first drive pulley 12 a plurality of times. Has been. Then, one end side of the first wire 9 is pulled out from the fixed end 13 of the apparatus main body and is wound around a movable pulley 15 rotatably attached to the second optical system 2 by a half round, and thereafter, is fixed by the wire clamp portion 14. It is fixed to the first optical system 1, passes through a fixed pulley 16, and is wound around a first drive pulley 12. After passing through the first drive pulley 12, the first wire 9 passes through the fixed pulley 17 and the fixed pulley 18 and then the movable pulley 15
It is wound around a half circumference and is fixed to a fixed end 20 of the apparatus main body via a spring 19.

That is, in the case of such a system, the drive-side bearing is composed of a bush that fits with a shaft having a circular cross section, and the drive-side guide shaft 3 and the slide bearing 5 are provided.
There is always a gap between a and 5b. Due to this gap, vibration is generated when the first and second optical systems 1 and 2 move, and it is known that this vibration is particularly remarkable on the driven side. When this vibration occurs, the first and second optical systems 1 and 2
In this case, the driven side is advanced or delayed with respect to the driving side, and the original image is read in this state, so that the original is read twice or overwritten.

Then, the above-mentioned Japanese Patent Laid-Open No. 55-12143.
In Japanese Patent No. 0, the magnetic means is provided on the driven side of the first and second optical systems to suppress the vibration. In addition, as disclosed in Japanese Utility Model Laid-Open No. 54-181949,
There is also a system in which a driven device of the two optical systems is provided with a vibration damping device in which a wire for urging the first and second optical systems in a fixed direction and a spring are combined. However, in the case of these methods, the action of suppressing the vibration on the driven side is only passive, and the damping effect thereof is insufficient. This is the actual exploitation 54
As shown in Japanese Patent Publication No. 181949, even when the driving force acts on the driven side as well, the wire has an open loop configuration, and the optical system is driven via the spring. There is a drawback that it increases.

On the other hand, as shown in Japanese Patent Laid-Open No. 58-95762, a double-sided wire drive system has been proposed in which wires are provided on both sides of the first and second optical systems to drive them. This method has been put to practical use in a copying machine in which the optical system moves at a high speed of 150 to 300 mm / sec, but 5 to 5
This is an excessive configuration for a device in which the optical system moves at a low speed of about 0 mm / sec, and the structure becomes complicated.

It is also proposed to improve the system of FIG. 11 so that only the first optical system 1 is driven by both sides and the second optical system 2 is driven by one side as shown in FIG. . First, the second wire 21 is also provided on the driven side of the first optical system 1, that is, on the driven side guide shaft 4 side. The second wire 21 uses the step motor 10 for the first wire 9 as a common drive source, and is wound around the second drive pulley 22 provided on the drive shaft 11 a plurality of times. And
One end of the second wire 21 is fixed and pulled out by the wire clamp portion 23 of the first optical system 1, wound around the second drive pulley 22 via the fixed pulley 24, and then passed through the fixed pulley 24 again to the other end. The other end is fixed to the wire clamp portion 23 by being wound around the fixed pulley 25 on the side. That is, the second wire 21 is wound in a closed loop.

However, even if only the first optical system 1 is of the double-sided driving type in this way, it is disadvantageous in terms of space in view of the driving force transmission path and the like.

[0010]

In consideration of such a point, as a driving method, for example, a one-side driving method as shown in FIG. 11 and a method of providing a vibration damping mechanism for suppressing the vibration on the driven side is proposed. Considered good. In this respect, Shokai 5
According to Japanese Patent Laid-Open No. 4-181949, a one-sided drive system is provided with a vibration damping mechanism. That is, the one-sided drive system has the same configuration as that shown in FIG.
On the driven side of the traveling body, a vibration damping device is provided which is a combination of a wire, a spring and a pulley for constantly urging the driven side end portion in a fixed direction. Specifically, as shown in FIGS. 2 and 3 of the publication, a large-diameter pulley and a small-diameter pulley are coaxially attached to the driven side of the second traveling body, and the timepiece is operated during the sub-scanning. The large-diameter pulley draws out the first wire, the small-diameter pulley winds up the second wire, and the second wire is pulled toward the pulley. The opposite sides of the first and second wires are respectively wound around other large-diameter pulleys and small-diameter pulleys attached to the main body of the apparatus, and these pulleys also rotate clockwise,
The large-diameter pulley winds the first wire pulled out,
The small diameter pulley is adapted to pull out the second wire.
The reverse operation is performed during the return operation.

However, in such a mechanism, the two large-diameter pulleys and the first wire are for winding the second wire pulled out during the sub-scanning around the small-diameter pulley attached to the apparatus main body side during return traveling. It is a mechanism. Therefore, such a vibration damping device also requires a mechanism unrelated to vibration damping, and cannot be said to have a simple structure.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is provided with a light source for illuminating an original to be read, an optical system member such as a mirror for reflecting light reflected from the original, an image sensor, and the like. A one-sided drive system including a body, guide members disposed on both sides of the traveling body to guide the traveling body to reciprocate in the sub-scanning direction, and drive means connected to only one side of the traveling body. In the moving optical system, a movable pulley is provided on the driven side of the traveling body, and a part of the movable pulley is wound more than at least one round to extend in the sub-scanning direction, and the movable pulley is arranged in the guide member direction. It is characterized in that a wire stretched so as to give a component force is provided, and at least one end of this wire end portion is locked to the apparatus main body via an elastic member.

[0013]

The vibration such as advance or delay in the sub-scanning direction that may occur on the driven side of the running body can be balanced and suppressed on both sides of the running body in the sub-scanning direction by the wire with the elastic member, so that stable running can be performed. It is possible to perform stable reading, especially to prevent floating of the movable pulley from the guide member, and not to drive the driven side and to urge only in a fixed direction. Since unnecessary parts are not needed, the structure is simple, the cost is low, and the space is small.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, in this embodiment, the first optical system 1
The present invention is applied to a copying machine or the like in which a traveling body is composed of the second optical system 2 and the second optical system 2, and these are sub-scanned at a speed ratio of 2: 1 as in the case of FIG. The same parts as those shown in FIG. 11 are designated by the same reference numerals. First, a movable pulley 26 is rotatably attached to a fixed shaft 27 at the driven-side end of the first optical system 1. That is, the movable pulley 26 moves together with the first optical system 1. And this movable pulley 2
On the driven side where 6 is provided, one second wire 40 is provided along the sub-scanning direction.

Here, the tension spring 41 is attached to the second wire 40.
The tension given by the (elastic member) is set to be the same as the tension of the first wire 9 on the drive side in order to balance the first optical system 1. here,
So that a downward force acts on the movable pulley 26,
The locking point is set lower than that of the movable pulley 26 so as to extend obliquely downward to the locking points from the movable pulley 26 to the fixed ends 29 and 32 (apparatus main body) at both ends of the second wire 40 (wire). That is, in the present embodiment, the vibration on the driven side in the vertical direction is also suppressed.

In such a configuration, when the drive shaft 11 is rotated in the predetermined direction by the step motor 10, the first
The wire 9 is wound up in a predetermined direction by the drive pulley 12. As a result, the movable pulley 15 moves in the arrow A direction while rotating, and moves the second optical system 2 in the arrow A direction. By moving the movable pulley 15 in the arrow A direction in this way, the wire clamp portion 14 of the first optical system 1 is also pulled in the arrow A direction. As a result, the first optical system 1
Also moves in the direction of arrow A. At this time, the action of the movable pulley 15 provided in the second optical system 2 causes the first optical system 1 and the second optical system 2 to move.
The optical system 2 moves while maintaining a speed relationship of 2: 1. In this way, the first and second optical systems 1 and 2 have the arrow A
Are driven in the sub-scanning direction.

At this time, the first optical system 1 is driven by the first wire 9 on the driving side, but on the driven side, the second wire 40 and the tension spring 41 (elasticity) from both sides in the sub scanning direction with respect to the movable pulley 26 portion. Since the tension is applied by the (members), it is driven in a balanced state. In this respect, for example, the actual exploitation Sho 54-181949
This is different from the one in which the driven side is urged only in one fixed direction as shown in Japanese Patent Publication No. In this way, since the first optical system 1 moves in the direction of arrow A, there is no occurrence of vibration such as delay or advance to the driven side by driving it on one side. Therefore, the document reading is stably and accurately performed.

By the way, in FIG. 1, although the bearing spacing between the slide bearings 5a and 5b for the first optical system 1 is shorter than the bearing spacing between the slide bearings 6a and 6b for the second optical system 2, Since the moving speed of the first optical system 1 is faster, it has an irrational configuration. However, when the traveling space of the optical system is small as compared with the length of the original, this combination inevitably results. Under such a structure, for example, in the case of a copying machine, the first and second optical systems 1 and 2 continuously perform exposure scanning at a constant speed, so that they are delayed or advanced to the driven side of the first and second optical systems 1 and 2. Occurs periodically, and this becomes vibration. On the other hand, even with the same configuration, in an image reading device such as a digital scanner, the writing speed and the capacity of the buffer memory and the frame memory in the connected device (host machine, printer, plotter, display, etc.) As a result, the optical system is stopped and started (temporarily stopped, restarted) while the document is being read. At the time of this stop and restart, the gaps of the slide bearings 5a to 6b with respect to the drive-side guide shaft 3 cause advance or delay on the driven side of the first and second optical systems 1 and 2, and do not read or read the original twice. Will occur. Here, the vibrations (advance or delay) generated on the driven side of the first and second optical systems 1 and 2 are the sliding bearings 5a, 5b, 6a, 6 of the optical systems 1, 2.
It is inversely proportional to the bearing spacing of each b, and is proportional to the gap between the drive side guide shaft 3 and the slide bearings 5a to 6b. Numerically, when the manuscript size A4 is 297 mm long and the running space of the optical system is 400 mm, if the gap between the shaft and the bearing is about 0.03 to 0.05 mm, the first optical The amount of advance or delay on the driven side of the system 1 is 0.2 to 0.5 mm, and the amount of advance or delay on the driven side of the second optical system 2 is 0.03 to 0.07 mm.
About. As a result, it can be said that the vibration damping device may be omitted for the second optical system 2.

However, in this embodiment, the movable pulley 26 and the one second wire 40 are provided together with the tension spring 41 only on the driven side of the first optical system 1, so that The vibration (advance or delay) on the driven side can be suppressed. Therefore, JP-A-58-9576
Compared to the double-sided wire drive system as shown in Japanese Patent Publication No. 2 publication, its configuration is extremely simple. Further, compared to the system shown in FIG. 12 in which only the first optical system is driven on both sides, no drive path is required on the driven side, and the space is small and simple and economical. Furthermore, compared with Japanese Utility Model Laid-Open No. 54-181949, which is a one-sided drive system and is provided with a vibration damping device on the driven side,
Unlike the publication, the first optical system is not biased only in a fixed direction, but is balanced in both directions by a single second wire 40, so that no unnecessary parts are needed and the configuration is simple. It will be In this way, the vibration on the driven side of the first optical system 1 is suppressed, so that the original can be read stably and accurately, and double reading and over-reading can be eliminated.

As a means for suppressing such vertical vibration, there is, for example, one disclosed in Japanese Patent Publication No. 60-29932. This is because the optical system drive wire is tilted and stretched with respect to the guide rail so that the optical system exerts a turning force that pushes the roller against the guide rail on the driven side with the guide rail on the drive side as a fulcrum. Is. However, since this is the same as pressing the driven side of the optical system against the guide rail from above,
The damping effect is small with respect to the vibration in the sub-scanning direction on the driven side due to the gap between the bearing on the driving side and the guide rail, which is a drawback of the conventional one-sided driving system as described above. Further, since this method is effective at the position where the largest vibration is generated at the specific scanning start position and reversal start position, it can be used only in a copying machine or the like that exposes and scans a document at a stretch. This is not effective for an image reading apparatus in which the optical system repeatedly stops and starts in the middle of.

However, in this embodiment, since the second wire 40 is constructed as shown in FIG.
A force that pushes down 6 is generated. Therefore, the slide bearing 7 on the driven side of the first optical system 1 is pressed onto the driven guide shaft 4 and prevented from floating. FIG. 4B shows a state of the second wire 40 and the like when the first and second optical systems 1 and 2 are started, and FIG. 4A is a second state when the first and second optical systems 1 and 2 are returned. The state of the wire 40 and the like is shown. Here first
When the optical system 1 reaches the position shown in FIG. 4 (a) or (b), the second
The inclination angle of the wire 40 is maximized, and the force for pressing the slide bearing 7 against the driven guide shaft 4 is increased. here,
Since the damping effect of the second wire 40 stretched obliquely is only in the vertical direction, even if the pressing force becomes strong, the image reading will not be proportionately improved. Therefore, it is sufficient that the second wire 40 has the minimum pressing force required for vertical damping. In this way, according to the present embodiment, by only providing one second wire 40 on the driven side, it is possible to reduce the number of wires in the sub-scanning direction and the vertical direction.
The vibration damping function can be exerted in the direction, and the image reading can be performed in a more stable state.

Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the first and second optical systems 1,
In particular, the case where 2 is included, particularly the case where both scan with a speed ratio of 2: 1, is taken into consideration. Specifically, in the embodiment, the movable pulley 43 is provided on the shaft 42 fixed to the end of the second optical system 2 on the driven side, and the second wire 40 is moved from the movable pulley 26 side to the movable pulley 43. After passing through in a state of being in contact with the upper side, it is engaged with the fixed end 32 side obliquely below.

According to this structure, the vibration in the sub-scanning direction and the vibration in the vertical direction on the driven side of the first optical system 1 are suppressed at the same time, while the vibration on the driven side in the vertical direction of the second optical system 2 is suppressed. Can be suppressed, and more stable image reading becomes possible. Here, the amount of vibration of the second optical system 2 in the sub-scanning direction can be ignored because it is very small as described above, and the driven side of the second optical system 2 is the same as in the present embodiment. Any material can be used as long as it can suppress vertical vibration.

FIG. 7 is a view corresponding to FIG.
(a) shows the return time, and (b) shows the start time. Also in this case, when the first and second optical systems 1 and 2 are positioned in the illustrated state, the inclination angle of the second wire 40 becomes maximum, and the force for pressing the slide bearings 7 and 8 against the driven guide shaft 4 becomes strong.
However, even if the pressing force is increased as described above, the effect does not increase correspondingly. If it is too strong, the frictional force is increased and the load on the motor 10 is increased. Therefore, the minimum pressing force required for damping can be applied from the second wire 40. That is, the second wire 40
The second wire 40 may be stretched so that the pressing force is at the minimum necessary when the gradient angle of is minimum.

Next, a third embodiment of the present invention will be described with reference to FIGS. In this embodiment, the second wire 40 is used not only for the movable pulley 26 of the first optical system 1 but also for the second optical system 2.
The movable pulley 43 is also wound (the winding direction is from the bottom in the figure, but may be from the top). That is, the second embodiment is further improved. According to the second embodiment, the vibration suppression of the first optical system 1 in the vertical and horizontal directions and the second vibration
Vibration of the optical system 2 in the vertical direction is suppressed. However, from a practical point of view, the sliding bearings 6a and 6b on the driving side of the second optical system 2 and the driving side guide shaft 3 are considered in terms of design, processing, cost, and space. If the gap between the sliding bearings 6a and 6b is shortened, or the vibration (advancing in the sub-scanning direction) such as advance or delay on the driven side cannot be ignored,
The vibration cannot be suppressed.

Therefore, in this embodiment, the second wire 40 is wound around the movable pulley 43 on the driven side of the second optical system 2 several times.
The state is the same as the driven side of the first optical system 1.
As a result, even when the vibration on the driven side of the second optical system 2 becomes conspicuous, the vibration in the sub-scanning direction such as advance or delay on the driven side is suppressed by the second wire 40.

In this case, the second wire 40 is moved from the movable pulleys 26 and 43 to the fixed ends 29 and 32 as shown in FIG.
If it is stretched so as to face downward, it is possible to suppress both the vertical scanning vibration and the vertical scanning vibration on the driven side of the first and second optical systems 1 and 2.

In these embodiments, the one-side wire drive system is used, and the first and second reciprocating movements are performed at a speed ratio of 2: 1.
Although the example of application to the optical systems 1 and 2 has been shown, the driving means is not particularly limited.

[0029]

As described above, the present invention provides a traveling body equipped with a light source for illuminating an original to be read, an optical system member such as a mirror for reflecting the reflected light from the original, an image sensor, and the like, and a traveling body of this traveling body. In the moving optical system of the one-sided drive system, which is provided on both sides, the guide member that guides the traveling body so as to reciprocate in the sub-scanning direction, and the drive means connected to only one side of the traveling body, A movable pulley is provided on the driven side of the body, and at least a part of the movable pulley is
A wire wound so as to be wound more than the circumference and extended in the sub-scanning direction and stretched so as to give a component force in the guide member direction to the movable pulley, and at least one end of this wire end portion is provided through an elastic member. Since it was locked to the device body,
Vibrations that may occur on the driven side of the moving body, such as advance and delay in the sub-scanning direction, can be balanced and damped on both sides of the moving body in the sub-scanning direction using a wire with an elastic member, and stable image reading can be achieved by stable running. In particular, it is possible to prevent the movable pulley from floating from the guide member, and not to drive the driven side, and to urge only in a fixed direction. Since unnecessary unnecessary parts are not required, the structure is simple, the cost is low, and the space is small.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a front view showing a part of the device in an enlarged manner.

FIG. 3 is a front view of a driven side.

FIG. 4 is a front view at the time of returning and starting.

FIG. 5 is a plan view showing a second embodiment of the present invention.

FIG. 6 is a front view thereof.

FIG. 7 is a front view when returning and when starting.

FIG. 8 is a plan view showing a third embodiment of the present invention.

FIG. 9 is a front view thereof.

FIG. 10 is a front view showing a modified example.

FIG. 11 is a plan view showing a typical example of a one-side drive system.

12 is a plan view showing the improved system of FIG. 11. FIG.

[Description of Reference Signs] 1 first optical system (running body) 2 second optical system (running body) 3 drive side guide shaft (guide member) 4 driven side guide shaft (guide member) 10 motor (driving means) 26 movable pulley 29 Fixed End (Device Main Body) 32 Fixed End (Device Main Body) 40 Second Wire (Wire) 41 Tension Spring (Elastic Member)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H04N 1/10 1/107 H04N 1/10

Claims (1)

[Claims] 1. A traveling body equipped with a light source for illuminating an original to be read, an optical system member such as a mirror for reflecting light reflected from the original, an image sensor, and the like, and the traveling bodies provided on both sides of the traveling body. In a moving optical system of a one-sided drive system, which includes a guide member that guides a body to reciprocate in a sub-scanning direction and a drive unit that is connected to only one side of the traveling body, a movable pulley is provided on a driven side of the traveling body. A wire is provided so that a part of the movable pulley is wound more than at least one turn to extend in the sub-scanning direction, and a wire is stretched to give a component force to the movable pulley in the guide member direction. A vibration damping device for a moving optical system, wherein at least one end of the end portion is locked to the main body of the device via an elastic member.