JPH02101868A - Original reader - Google Patents

Abstract

PURPOSE:To avoid occurrence of short-circuit and to ensure the reading even if a cable is worn by floating or connecting a core wire to ground at one side of a flat cable easily grounded to other member among flat cables prolonged from a read section of an original reader connecting to a copying machine or a printer. CONSTITUTION:Since flat cables C1-C3 connecting to a main scanning base reciprocating a subscanning part U, that is, a read section 1 are supported by a bottom face of a cable guide 25 for each main scanning, even if the main scanning base 1 is moved in the main scanning direction, they do not rub the bottom plate O in the case of feeding. However, since the flat cables rub the cable guide 25 at both sides depending on the way of wiring during the use for a long period, the sheath part is worn and the core wire may be in contact with the metal-made guide 25, short-circuited thereby disabling signal transmission/reception. Then wire codes C1a, C1b at both ends of the wider cable C1 are fixed at the bottom plate O and the main scanning base 1 by terminals N3, N4 to keep the core wire the same potential as that of the bottom plate O.

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 direction of arrow Y (main scanning direction) while illuminating the document to read a predetermined area, and then the reading device 10o is moved in the direction of arrow X (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, the flat cable is bent in the main scanning direction, and a support member is also used.

A device has also been devised that can improve the durability of the cable and reduce the size of the device by restricting its movement with a guide member or the like.

However, in the case of such conventional examples, the flat cable rubs against the guide member, which is usually made of metal, and the coating at the end of the cable wears out after long-term use, causing a short circuit at this part. There were cases where signals could not be exchanged.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to prevent reading problems even if the flat cable for wiring to the moving reading unit is worn out. (The objective is to provide a document reading device that can withstand long-term use.)

(Means for Solving the Problems) In order to achieve the above object, the present invention has a reading optical system and electrical parts of the reading optical system in order to guide the optical image of the original to the light receiving section. On the other hand, in a document reading device in which a reading section wired using a flat cable is moved at a predetermined speed, at least one side of the flat cable extending from the reading section is in a core grounded state or in a floating state. .

(Function) In the present invention having the above configuration, since the core wire on at least one side of the flat cable extending from the reading section is grounded or floated, the potential of this portion becomes the so-called earth potential, Even if the covering portion is worn and the core wire comes into contact with a guide member or the like, no short circuit will occur. Furthermore, since such core wires are not used for wiring, there is no possibility that signals cannot be exchanged in the above case.

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

1 to 11 show an embodiment of a document reading device according to the present invention, FIG. 2 is a plan view of the main part thereof, and FIG. 3 is a perspective view.

As shown in the figure, the main scanning metalwork of this embodiment is provided on a sub-scanning section U, and these constitute a reading section. The main scanning table 1 is mounted so as to be movable within a plane parallel to the document surface by the following configuration. First, the main scanning table 1 is placed on the imaging lens. It holds the C0D 20 and the like as a light receiving section and reciprocates on a pair of rails 2a and 2b of a sub-scanning section U provided in the main scanning direction (arrow A or B direction). The rails 2a and 2b are held between the sub-scan front side plate 3 and the rear side plate 4. 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 moving the wire pulley 5 press-fitted into the stepping motor M and the wire 6 wound around the pulley 22 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. A spring 7 and a tension spring 8 are interposed therebetween. Note that 19 is a fixing plate for fixing the spring 7 and the tension spring 8 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 sub-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 boob 915 is transmitted to the large pulley 13 by the timing belt 14 to rotate the sub-scanning wire boob 912, and the pulley 12 and the sub-scanning front and rear side plates 3 Wire 1 connected to .4
0.11, these front and rear side plates 3.4 are moved in the direction of arrow C.

In addition, in FIG. 3, Sl is a sensor that detects the stop position of the main scanning table 1. Scanning of the main scanning table 1 starts from this position, and the document is read from the position of the sensor S2 provided near the sensor S1. Start. Furthermore, S3 is a sensor that detects 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.

1 is a perspective view clearly showing the vicinity of a portion to which a flat cable is connected, FIG. 4 is a view taken in the Q direction in FIG. 1, and FIG. 5 is a view taken in the R direction in FIG. 1.

As shown in the figure, the flat cables C1, C2, and C3 wired from predetermined parts of the main body of the device are fixed to the bottom plate O 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 six directions of the arrows 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 21 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
Fix the flat cables CI and C2 to the bottom of the
The back plate 31 is fixed to the upper surface of the fixture 3o 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 the flat cable C2 is connected to the wiring cord to the fan 34 and the lamp 3.
Divided into 3 wiring codes. The flat cable c1 is folded back on the wiring guide 35 as shown in the figure,
It is connected to the lower printed circuit board PCB via connectors 36 and 37.

The width of the U-shaped cable guide 25 may be made slightly wider than the width of the flat cables 01 to C3. With this configuration, the flat cables 01 to C3 are supported by the bottom surface 25a of the cable guide 25, so
Even while the main scanning table l 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, 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 on both sides
Even if the coatings 1a and C1b are torn and come into contact with a metal part, the same problem will not occur because that part is at so-called earth potential. In this case, if only one side of the wiring cord is likely to wear out, a configuration in which only one side is grounded may be used. Further, the same effect can be obtained even if the wiring cords C1a and C1b are not grounded but are in a floating state (insulated state). Note that in devices that do not have a cable guide, the trajectory of the flat cable may pass through unexpected places, so if the above configuration is adopted, short circuits and the like can be similarly prevented.

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

In general, machines that are built lower in height will take up less space, have more freedom in installation, and are easier to operate. However, as shown in FIG. 5, if the height of the main body of the device is reduced without providing the fixing plate 32, the flat cables C1, C2 and the back plate 31 will move along the dashed line a in the figure as they move during reading. As shown, the flat cable C1°C2 bent and rubbed against the glass G on which the original is placed.
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 apparatus will become larger. Therefore, in this embodiment, the fixing plate 32 is bent downward as shown in the figure to press down the flat cables CI, C2 and the back plate 31, and the flat cables C1, C2 are
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 and 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 C1, C2, etc.

Here, we will discuss the effects of the back plate 27.31: (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 cables C1 and 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. 1 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 diagram of the device shown in FIG. 1 viewed from the direction of arrow T, with the slide member 44 fixed to the front and rear sub-scanning side plates 3 and 4 riding on the rail 9 and grounded. 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. 1, 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 in order from the inside to the outside in descending order of strength.

Furthermore, stable bending of the flat cables C1 to C3 is achieved by arranging the cables from the inside to the outside in order of widest width. 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 if the back plate 27
It may come off and cause a malfunction. Therefore, as in this embodiment, the back plates 27. Stack the flat cables 01 to C3, then attach the back plate 27 in order of widest width.
．． It is necessary to overlap the flat cables C1 to C3 to maintain a stable bent state.

Further, as shown in FIG. 11, by giving the back plate 27a a curvature in a 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 can be kept low, there is an 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 C1 to C3. As a result, the back plate 27 and the flat cable C
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 main scanning table 1 is too stiff, the main scanning table 1 will float up, resulting in what is called an out-of-focus state or hindering movement. 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, the flat cables C1 to C3 are
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. 2 and 6. (In order to have a configuration that does not protrude, it is necessary to place it in an area where it does not interfere with the movements of the sub-scanning unit U and the main scanning platform 1, so the width or height of the main body of the device increases as shown in Figure 2. ).

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 conventional devices that read images by scanning, even if the flat cable hit the frame at the home position, there was a run-up distance of several tens of millimeters, so it was not a problem as long as it did not hit at the position where reading started. However, in the device of this embodiment, the home position, that is,
In Fig. 2, the sub-scanning section U moves the main scanning platform 1 in the six directions of the arrows from the position detected by the sensor S3 to perform reading, so when the sub-scanning section U is at the home position, other flat cables are scanned. 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 C1 to C3 are provided in the frame 45, so that the flat cables 01 to C3 can be removed 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.

In addition, in the above embodiment, C0D20 is used as the light receiving section.
Although the description has been given by taking an example of a device for guiding a light image of an original document, the present invention is not limited to this, 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, at least other members of the flat cable extending from the reading section and the core wire on one side of the flat cable that is not grounded are grounded or floated. Even if the flat cable for wiring to the section is worn out, short circuits will not occur, and as a result,
This has the effect of allowing reliable reading over a long period of time.

[Brief explanation of the drawing]

1 to 11 show an embodiment of the document reading device according to the present invention. The figure is a plan view showing the main parts of the same embodiment, Figure 3 is a perspective view showing the device in Figure 2, and Figure 4 is the Q direction arrow in Figure 1 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. 1 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 l...Main scanning table (reading part) 2a, 2b...Rail 9...Sub rail 20...COD (light receiving part) 25...Cable guide 26...Fixing tool 32 ...Fixing plates A, B...Main scanning direction arrow C, D...Sub scanning direction arrow 25a...Bottom 27.31...Back plate 33...Lamp 6...Wire CI, C2 , C3...Flat cable C1a, C1
b...Wiring code U...Sub-scanning section Fig. 9 Fig. 10 Fig. 11 Fig. 12

Claims (1)

[Scope of Claims] In order to guide the optical image of the original to the light receiving section, a reading section having a reading optical system and wiring to the electrical components of the reading optical system using a flat cable is moved at a predetermined speed. What is claimed is: 1. A document reading device characterized in that a core wire on at least one side of a flat cable extending from the reading section is grounded or in a floating state.