JPH02101867A - Original reader - Google Patents

Abstract

PURPOSE:To eliminate the effect of the stiffness of wiring flat cable even at a low temperature and to smooth the movement of a read section by leading the flat cable to a side of a guide rail at the side supporting a read section freely movably. CONSTITUTION:Flat cables C1-C3 wired from a prescribed part of a reader main body are fixed to a bottom plate O by using a fixing jig 26 and fitted to a rear plate 27 made of an elastic metallic plate made of phosphorous bronze. The cables C1-C3 are fixed to the bottom of a U-shaped cable guide 25 in a circular-arc in the subscanning direction by a fixed jig 28 in the rear plate 27, in this case, the cables C1-C3 are folded at an angle of nearly 90 deg. at the left end of the guide 25 and moved in the direction of arrow C or D together with the subscanning part U. The guide 25 is provided to an area not interferred when the main scanning base 1 is moved in the main scanning direction to attain contactless constitution thereby avoiding a cause to a fault. Thus, the cables C1-C3 are supported at the bottom face of the guide 25 and do not rub the bottom plate O even if the main scanning base 1 is moved.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is applied to a reading optical system of a copying machine, or a copying machine,
The present invention relates to a document reading device connected to a printer or the like, and particularly to a document reading device equipped with a reading section that moves to guide an optical image of the document to a light receiving section.

(Prior Art) In recent years, copying machines have replaced the so-called analog copying machines, which form images by guiding the light image of the original onto a photoreceptor, by reading the original image using a reading means such as a COD image sensor The number of so-called digital copying machines that are composed of a document reading device that outputs a signal and a printer that forms a document image on recording paper in accordance with the electrical signal is increasing.

Conventionally, in such document reading devices, from the viewpoint of availability and cost reduction, as shown in FIG. 12, a very short C.
An OD is used as the reading means 100. When reading an image of a document, the reading device 100 is moved in the arrow Y direction (main scanning direction) while illuminating the document to read a predetermined area, and then the reading device 100 is moved in the arrow X direction (sub scanning direction). The entire surface of the document is read by repeating the operation of moving the scanner in the scanning direction and reading the next area. By adopting such a configuration, it is possible to provide a lightweight, compact, and inexpensive device.

(Problem to be Solved by the Invention) By the way, in such a conventional example, the reading means 10
0 is built into the reading section along with the illumination lamp, lens, etc., and since this reading section moves vertically and horizontally as mentioned above, it is necessary to connect the reading section with safe, compact, and durable wiring (power supply, signal reception). It is necessary to carry out (e.g. handing over).

However, in the past, in order to avoid applying extra force to the wiring cables, cables were routed by hanging them from the bottom of the device over a fairly long distance, or flat cables were used to prevent the flat cables from wandering. Because of this design, there were problems in that the cable was easily damaged and the device became larger.

Therefore, in recent years, it has become possible to improve the durability of the cable and downsize the device by bending the flat cable in the main scanning direction and restricting its movement with support members, guide members, etc. A device has also been devised.

However, in such a conventional example, the flat cable is guided between two rails on which the reading unit is placed, that is, below the reading unit, so that if the flat cable hardens at low temperatures, the cable and Due to the stiffness of the support member, the reading unit tends to lift off the rail, which causes the reading optical system to become out of focus and the movement of the reading unit to be inhibited, resulting in image distortion. Ta.

Therefore, the present invention has been made to solve the problems of the prior art described above, and its purpose is to eliminate the influence of the stiffness of the flat cable for wiring and to smoothly move the reading unit. The object of the present invention is to provide a document reading device that can perform high-quality reading without defocusing or the like.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a reading optical system and electric components of the reading optical system in order to guide the optical image of the document to the light receiving section. In a document reading device in which a reading unit wired using a flat cable is placed on a pair of Ω guide rails and moved at a predetermined speed, the reading unit is connected to one of the pair of guide rails. It is characterized in that the flat cable is held movably by the reader, and the flat cable is guided to the side of the guide rail on the side that holds the reading unit.

(Function) In the present invention having the above configuration, since the flat cable is led to the side of the guide rail on the side that movably holds the reading unit, the force in the direction of lifting the reading unit from the flat cable is reduced. When a cable is applied, a force acts in the direction of pressing the reader against the other guide rails, centering on the guide rail on the side that holds the reader. Therefore, this is particularly true in devices that bend flat cables in the direction of movement of the reader. teeth,
Even when a force is applied due to the strength of the body at low temperatures, it is possible to prevent the reading section from lifting up.

(Example) The present invention will be explained below based on illustrated embodiments.

1 and 2 are a plan view and a perspective view showing essential parts of an embodiment of a document reading device according to the present invention. As shown in the figure, the main scanning platform 1 of this embodiment is provided on a sub-scanning section U and serves as a reading section. And main scanning platform 1
is mounted so as to be movable within a plane parallel to the document surface using the following configuration. First, the main scanning table 1 holds a lens L for imaging, a C0D20 as a light receiving section, etc., and has a pair of rails 2a, 2b in a sub-scanning section U provided in the main scanning direction (direction of arrow A or B). It is placed on the ground and reciprocates in the same direction. These rails 2a and 2b are held between the sub-scan front side plate 3 and the rear side plate 4, and serve as guide rails. Main scanning for one line is performed by moving the main scanning table 1 back and forth in the directions of arrows A and B on these rails 2a and 2b. In this case, the reciprocating drive is performed by the wire pulley 5 and the pulley 22 press-fitted into the stepping motor M.
This is done by moving the wire 6 that is wound around the main scanning table 1 and connected to the main scanning table 1.

In this embodiment, the wire 6 is connected to the main scanning table 1 from both sides in the main scanning direction, and in this case, the spring 7 and the tension spring 8 having a predetermined spring constant are used.
is interposed.

Then, move the main scanning table 1 in the direction of the arrow to scan the CCD 20.
When performing reading, the main scanning table 1 is driven by the spring 7, and the vibration of the wire 6 due to the vibration generated by the stepping motor M or resonance with this vibration is absorbed by the spring 7, so the vibration of the wire 6 is It is not transmitted to the main scanning table 1.

Therefore, the main scanning table 1 moves smoothly along the rails 2a and 2b, and no vibration occurs in the C0D 20, so that a clear read image without expansion or contraction can be obtained. The tension spring 8 provided in the direction of arrow B is a weak spring that is almost the same as the spring 7, and is used to absorb the shock at the start of driving and the long-term elongation of the wire 6. Also, 19
is a fixing plate for fixing the spring 7 when the spring 7 and the tension spring 8 are stretched.

The sub-scanning front and rear side plates 3.4 are placed on a pair of sub-rails 9 provided in the anti-scanning direction (arrow C or D direction). Each time a main scan is performed, the motor 16 is rotated, and the rotation of the small pulley 15 is transmitted to the large pulley 13 by the timing belt 14 to rotate the sub-scanning wire pulley 12, and the pulley 12 and the sub-scanning front and rear side plates 3 are rotated. Wire 1 connected to .4
0°11 to move these front and rear side plates 3.4 in the direction of arrow C. Conventionally, it was said that if the drive side is reciprocated through an elastic or elastic body such as a spring, reading defects will occur due to transient vibrations, but springs 7 and 8 with appropriate spring constants are selected. Then, the main scanning table 1 can be moved smoothly without this unevenness.

In addition, in FIG. 2, S is a sensor that detects the stop position of the main scanning table 1. Scanning of the main scanning table 1 is started from this position, and the original is detected from the position of the sensor S, which is installed near the sensor S1. Start reading. Further, S3 is a sensor for detecting the stop position (home position) of the main scanning platform 1 in the sub-scanning direction, and is designed to detect the end of the sub-scanning section U as shown in FIG.

By the way, in an apparatus having such a configuration, the lamp 33 and the CCD 20 provided on the moving main scanning table 1 are
It is necessary to wire the electrical components such as those to supply power and exchange signals.

One way to supply power to moving objects is to use flat cables, which are made of multiple ribbon-shaped cords coated with vinyl or rubber, or flexible films, which have copper wires printed on the film (hereinafter collectively referred to as flat cables). However, digital and color reading requires a large number of signal lines, and also requires multiple cables with different pitches and thicknesses to match the elements and connectors used. The space for wiring made the device configuration large.

3 is a perspective view clearly showing the vicinity of the part to which the flat cable is connected, FIG. 4 is a view taken in the Q direction in FIG. 3, and FIG. 5 is a view taken in the R direction in FIG. 3.

As shown in the figure, the flat cables CI, C2, and C3 wired from a predetermined part of the main body of the device are fixed to the bottom plate 0 by a fixture 26, and are made from an elastic metal plate (phosphor bronze, stainless steel, etc.). The back plate 27 is fixed to the back plate 27 so as to be in close contact with each other, and the back plate 27 is further fixed with screws N1.
is fixed to the upper surface of the fixture 26. And back plate 2
Together with the flat cables 01 to C3, the flat cables 01 to C3 are fixed to the bottom 25a of the cable guide 25, which is made of metal and has a substantially U-shaped cross section, by a fixture 28 while drawing a circular arc in the sub-scanning direction. In this case, the flat cables 01 to c3 are connected to the cable guide 25.
The cable guide 25 is folded back in the direction of the arrow at an angle of approximately 90'' at the left end of the cable guide 25.As shown in FIG. The cable guide 25 is configured to move in the direction of arrow C or D together with the sub-scanning section U. In this case, the cable guide 25 is provided in an area where it does not interfere with the movement of the main scanning table 1 in the main scanning direction. , the main scanning table 1 and the cable guide 25 do not come into contact with each other, and this will not cause a malfunction.

The flat cable C3 has a wiring cord C3a connected to the motor 2J for adjusting the length of the spring 7 near the left end of the cable guide 25, and a wiring cord C3b connected to the stepping motor M.
It is divided into two parts. Note that 29 is a stopper for fixing the wiring cord C3 at the right end of the cable guide 25.

The flat cable C2 wired to the main scanning table 1 is fixed near the approximate center of the cable guide 25 with a fixture 30 together with a back plate 31 similar to the above-described back plate 27. Regarding this fixed part, as in the case of the fixing member 26, the fixing member 30
The flat cables C1 and C2 are fixed to the bottom surface of the
The back plate 31 is fixed to the upper surface of the fixture 30 using screws N2 (see FIG. 5), which will be described later. The flat cables CI, C2 and back plate 31 are folded back in the main scanning direction (direction of arrow B) as shown in FIG. 35, and for the flat cable C2, connect the wiring cord to the fan 34 and the lamp 33.
Divided into wiring codes. The flat cable c1 is
As shown, it is folded back on the wiring guide 35 and connected to the lower printed board PCB via connectors 36 and 37.

The width of the U-shaped cable guide 25 should be slightly wider than the width of the flat cables C1 to C3. With this configuration, the flat cables 01 to C3 are supported by the bottom surface 25a of the cable guide 25.
Even while the main scanning table 1 is moving in the main scanning direction, power is supplied without rubbing against the bottom plate O or the like. Note that the flat cable 01 that extends upward from the cable guide 25 is
~ Even when the bending state of C3 is disturbed and slightly shifted as shown by the two-dot chain line in Fig. 4, it is smoothly guided and the guide 25
This is to ensure that it fits within the In this case, depending on the wiring method, the flat cable may
Since it rubs against the cable guides 25 on both sides, the sheath may wear out, and the core wire may come into contact with the metal cable guides 25, resulting in a short circuit or an inability to exchange signals. Therefore, in this embodiment, in order to prevent such a failure from occurring, the wiring cords C1a and C1 at both ends of the widest flat cable C1 are arranged as shown in FIG.
1b on the bottom plate 0 side and the main scanning table 1 side with screws N3. N
4, and are configured so that they are at the same potential as the bottom plate O. Therefore, if the wiring code C at both ends is
Even if the coating of 1a and C1b is torn and comes into contact with a metal part, that part is at so-called earth potential, so there is no problem of insult.This configuration can be used even when a U-shaped cable guide is not used. It is valid.

Next, the effect of the fixing plate 32 will be described.

In general, machines that are built low in height also take up less space, have more freedom in installation, and are easier to operate. However, as shown in FIG. If the height is lowered, the flat cables C1, C2 and the back plate 31 will bend as shown by the dashed line a in the figure as they move during reading, and will rub against the glass G on which the original is placed, causing the flat cable C1° C2
This may obstruct the movement of the main scanning table 1 or cause dust to adhere to the lower surface of the glass G. On the other hand, if the position of the glass G is raised to prevent this, the main body of the device will become larger.Therefore, in this embodiment, the fixing plate 32 is bent downward as shown in the figure, and the flat cables CI, C2 and Press the back plate 31 down and connect the flat cables C1 and C2.
This structure prevents contact between the glass G and the glass G. Furthermore, at the position where the bending force is strongest, that is, near the end of the scan where the free length of the spring becomes short as shown by the two-dot chain line in FIG.
is located at a position where it does not push the flat cables C1-C2 or the back plate 31, and prevents the main scanning table 1 from being pushed up by the reaction force pushing the flat cables CI, C2, etc.

Here, we will discuss the effects of the back plates 27 and 31. (1) When the flat cable becomes stiff, specifically when the scanning length is long or the temperature is high (2) When the flat cable is left unused for a long time (3) If you have to use a cable that is already thin and weak, use a spring material (made of stainless steel or phosphor bronze with a thickness of 0.5 mm).
By inserting a back plate with a thickness of 1 to 0.3 mm, it is possible to prevent the flat cable C1°C2 from sagging as shown by the dotted line in FIG. If the cable is bent and the upper and lower cables come into contact, the cable sheathing is made of a material with a high coefficient of friction such as vinyl or rubber, so the cable may become stuck in contact, or the main scanning table may not move properly as the cable is not bent properly. However, as a countermeasure against this problem, the above configuration is very effective.

Similar to the grounding of the wiring at both ends of the flat cable C1 as described above, it is also very effective to use the back plate 27, 31 as a grounding line, so this will be described below.

FIG. 6 is a diagram of the device shown in FIG. 3 viewed from the direction of arrow S,
The main scanning table 1 is configured to be movable on rails 2a and 2b. That is, the rail 2a is moved by bearings 43a and 43b attached to shafts 39 and 40 fixed to the main scanning table 1, and bearings 43c attached to a shaft 42 fixed to a leaf spring 41 fixed to the main scanning table 1. The bearing 43d, which is also attached to the shaft 38,
is placed on the axis 2b, and as a result, the main scanning table 1 is placed on the first axis 2b.
It is constructed so that it can be moved extremely easily in the direction of arrow A or B in the figure. In this case, as shown in FIG. 6, the main scanning table 1 is connected to the rail 2a via bearings 43a to 43d
, 2b, so it is not grounded, which is undesirable in terms of noise. Similarly, FIG. 8 is a view of the device shown in FIG. 3 viewed from the direction of arrow T, with the slide member 44 fixed to the front and rear sub-scanning side plates 3.4 riding on the rail 9 and disconnected from the ground. It is not. Therefore, when reading is performed by repeating main scanning and sub-scanning, both the main scanning table 1, which moves in the main scanning direction, and the sub-scanning unit U, which moves in the sub-scanning direction, are in an electrically floating state because they are configured to be movable. easy to become. In this example,
As described above, in addition to using the wiring cords C1a and C1b at the ends of the flat cable C1 as grounding wiring, the impedance is further lowered by grounding the back plate 27.31. That is, as shown in FIG. 3, the back plate 27.31 is screwed with screws N1.

By tightening with N2 or pressing with the fixture 28 or the fixing plate 32, the member that moves during main scanning or sub-scanning (main scanning table 1 or sub-scanning section U) is brought to the same potential as the bottom plate O, that is, to the ground. It can be completely removed. in general,
Floating (not grounded and not used for signals)
Metal can easily become a source of noise, but since the planar metal is grounded using the above measures, it also has a shielding effect, making it strong against external noise, and also allowing noise generated by itself to escape. It becomes difficult.

In addition, this back plate 27.31 is a stacked flat cable 01.
~ It also performs the function of regulating the arbitrary movement of C3.

Next, back plates 27, 31 and flat cables 01 to C3
I will explain how to stack the .

As mentioned above, it is possible to wire the reader in a narrow area by stacking multiple flat cables, but in this case, as shown in Figure 9, the back plate 27, which is the strongest, is placed inside. , and further flat cable 01
-C3 are stacked one on top of the other in order of stiffness on the outside.

Further, the flat cables C1 to C3 are bent in a stable manner by arranging the cables from the widest to the outermost. That is, if the narrow flat cable C3 is placed inside as shown in FIG. 10, the back plate 27 may fall down in the width direction, or in extreme cases, it may come off the back plate 27, causing a malfunction. Therefore, backboard 27. Layer flat cables 01 to C3,
In order of width, back plate 27, flat cable 01~
Overlapping C3 is necessary to maintain a stable bending state.

Further, as shown in FIG. 11, by making the back plate 27a have a curvature in the direction perpendicular to the bending direction, and by making the bend direction the side that wraps the flat cables 01 to C3 inside, the flat cables C1 to C3 can be It can also be made difficult to come off from the plate 27a. This bending amount j is approximately 0.1 to 0.2 times the width i of the back plate 27a, which is effective. In this case, by giving the back plate a certain curvature, the curvature when the back plate 27a bends becomes almost constant. Also, since the height of the flat cables CI and C2 is kept low, there is also the additional effect that the wiring space can be narrowed. Note that the width of the back plate 27a may be wider than the width of the widest flat cable C1.

Next, the arrangement of the flat cable will be described using FIG. 6.

As shown in the figure, in this embodiment, a lens L and a CCD 20 for reading are arranged approximately in the center of the rails 2a and 2b that guide the main scanning table 1, and the two rails 2a
, 2b are arranged with flat cables 01 to C3. As a result, the back plate 27 and the flat cable 0
Even if 1 to C3 are too stiff, the main scanning table 1 will be lifted off the rails 2a and 2b because a force acts in the direction of the arrow (counterclockwise) centering on the rail 2a, which is supported at three points. There's no need to put it away. For example, when the flat cables 01 to C3 are used at low temperatures, they become hard and difficult to bend, so if the flat cables 01 to C3 are arranged between the rails 2a and 2b, If the stiffness of the main scanning table 1 is too strong, the main scanning table 1 may float up, resulting in what is called an out-of-focus state, or the movement of the main scanning table 1 may be obstructed. However, with this configuration, such a thing does not occur.

Next, a method of arranging flat cables 01 to C3 mainly in the sub-scanning direction (direction of arrow C or D) will be described.

In the apparatus according to the present invention, the feed amount in the sub-scanning direction needs to be extremely accurate. In addition, it is preferable in various respects that the size of the device body be small in terms of installation space and weight.

On the other hand, flat cables 01 to C3
The structure must be such that it can be bent freely with sufficient margin. In this embodiment, in consideration of these points, the flat cables 01 to C3 are configured to protrude from the sub-scanning section U in the direction indicated by the arrow, as shown by part E in FIGS. 1 and 6. (In order to have a structure that does not protrude, it is necessary to arrange it in an area where it does not interfere with the movements of the sub-scanning section U and the main scanning table 1, so the width or height of the main body of the device increases as shown in FIG. 1.) .

Incidentally, if an unexpected force is applied to the flat cables 01 to C3, for example, if the force is applied to the position indicated by the arrow F in FIG. 6, the position of the sub-scanning section U will shift and the read images will not be connected. In the case of devices that read images by scanning, which has traditionally been ignored, even if the flat cable hits the frame at the home position, there is a run-up distance of several tens of millimeters, so it is not a problem as long as it does not hit at the position where reading starts. However, in the device of this embodiment, the home position, that is,
In Fig. 1, the sub-scanning section U moves the main scanning platform 1 in the direction of the arrow from the position detected by the sensor S3 to perform reading, so when the sub-scanning section U is at the home position, other devices are connected to the flat cable. It is necessary to prevent members from touching and becoming disconnected from the next row. Therefore, in this embodiment, escape holes 45a for the flat cables 01 to C3 are provided in the frame 45, so that the flat cables C1 to C3 are provided even when the sub-scanning section U is at the home position.
It is configured so that the frame 45 or the like does not come into contact with it and apply external force. To achieve this purpose, the portion may be recessed, such as frame 45A in FIG. In particular, when the frame is made of resin or the like, a frame 45A shown in FIG. 7 is preferable from the viewpoint of ease of manufacture and strength.

Incidentally, in the above embodiment, the CCD 20 is used as the light receiving section.
Although the present invention has been described using an example of a device for guiding a light image of a document onto a photoreceptor, the present invention is not limited thereto, and can also be applied to a device that guides a light image of a document to a photoreceptor.

(Effects of the Invention) As described above, in the present invention, since the flat cable is guided to the side of the guide rail on the side that movably holds the reading section, the flat cable for wiring can be used even under low temperatures. The reading section can be moved smoothly by eliminating the influence of the stiffness of cables, etc., and as a result, it is possible to always perform high-quality reading without defocusing.

The present invention is particularly effective when applied to a device in which a flat cable extending from the reading section is bent in the direction of movement of the reading section together with an elastic support member.

[Brief explanation of drawings]

1 to 11 show an embodiment of a document reading device according to the present invention, FIG. 1 is a plan view showing the main parts of the embodiment, and FIG. 2 shows the device of FIG. 1. A perspective view, FIG. 3 is an enlarged perspective view showing the wiring state of the flat cable to the main scanning table and the sub-scanning section, and FIG. 4 is an enlarged perspective view showing the wiring state of the flat cable to the sub-scanning section. Fig. 5 is a view taken in the R direction of Fig. 3 showing the condition of the flat cable as the main scanning table moves, and Fig. 6 is a side view showing the state of the main scanning table being assembled to the sub-scanning section. 7 is a side sectional view showing another example of the frame, FIG. 8 is a front sectional view showing how the sub-scanning section is assembled to the main body rail, and FIG. 9 is a front sectional view showing how the sub-scanning section is assembled to the main body rail. Figure 10 is an explanatory diagram showing the state of the assembly. Figure 10 is an explanatory diagram showing the state of the back plate when the flat cable arrangement is changed. Figure 11 is an explanatory diagram showing another example of the back plate.
The figure is an explanatory diagram for showing a reading operation. Explanation of symbols 1...Main scanning table (reading section) 2a, 2b...Rail (guide rail) 6...Wire 9...Sub-rail 20...COD (light receiving section) 25...Cable Guide 25a... Bottom 26... Fixture 27.31
...Back plate 32...Fixing plate 33...Lamp 3B, 39.42...Shaft 41...Flat springs 43a, 43b, 43c, 43d...Bearing A,
B...Main scanning direction arrows C, D...Sub scanning direction arrows CL, C1, C3...Flat cable U...Sub scanning section Fig. 9 Fig. 10 Fig. 11 Fig. 12

Claims (2)

[Claims] (1) In order to guide the optical image of the original to the light receiving section, the reading section, which has a reading optical system and is wired to the electrical components of the reading optical system using a flat cable, is placed on a pair of guide rails. In a document reading device that moves at a predetermined speed, the reading section is held movably relative to one of the pair of guide rails, and a side of the guide rail on which the reading section is held is held. A document reading device characterized in that the flat cable is guided in the opposite direction. (2) The document reading device according to claim 1, wherein the flat cable extending from the reading section is bent together with an elastic support member in the direction of movement of the reading section.