JPH0434344B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document reading device in a so-called digital copying machine, facsimile machine, etc.

As the above reading device, a solid-state image sensor such as a CCD with a large number of dot-like photodetectors arranged in the main scanning direction,
By forming an image of the original to be read with a lens and transporting the original in the sub-scanning direction, or by moving the image sensor and lens together in the sub-scanning direction,
Devices that read the entire surface of a document are known, but in order to image the width of the document in the main scanning direction on the image sensor at once, a lens with a long focal length is required, which increases the size of the device, and the image sensor However, it is difficult to increase this number, and therefore it is difficult to improve the resolution of reproduced images. There is also a device in which a movable reading head is configured with a small image sensor and a lens with a short focal length, and this head is moved back and forth in the main scanning direction, and the document is conveyed equally with rollers in the double scanning direction to read the entire surface of the document. However, this method has the disadvantage that it cannot read thick originals such as books, and even very thin originals tend to jam in the conveyance means, and the originals tend to wrinkle.

The main object of the present invention is to provide a document reading device that solves the various disadvantages mentioned above.

In order to achieve the above object, the present invention provides a reading carriage for reading a document, a first guide member for guiding the movement of the reading carriage in a first direction, and a movable base on which the reading carriage and the first guide member are mounted. and a second guide member that guides movement of the movable base in a second direction perpendicular to the first direction, and includes an operation of moving the reading carriage in the first direction and a movement of the movable base in the second direction. A document reading device that reads a document by repeatedly performing a moving operation includes a drive motor for moving the reading carriage and the movable base, and a first guide that engages with the drive motor and the reading carriage. a driving force transmitting member extending along the member and extending along the second guide member to form a closed loop; a first inhibiting means for inhibiting movement of the reading carriage in the first direction; a second prohibition means for prohibiting movement of the stand in the second direction; the second prohibition means is actuated to cause the drive motor to move the drive force transmission member, thereby causing the reading carriage to move in the first direction. The movable base is moved in the second direction by activating the first inhibiting means and moving the driving force transmitting member by the drive motor.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of the main parts of an embodiment of the present invention, as viewed in the main scanning direction (X direction), that is, a direction perpendicular to the sub-scanning direction (Y direction), and FIG. 2 is an illustration of the same embodiment. FIG. 3 is a perspective view of the main parts of the same embodiment, and is a view taken in the sub-scanning direction, that is, a direction perpendicular to the main scanning direction.

In the figure, O is a document to be read that is placed stationary on a document table glass 1 fixed to a box body 2 of the main body of the document reading apparatus. 3 is a movable carriage. A small lamp 4, a mirror 5, a short focal length lens 6, and a CCD 7 are fixed to the carriage 3. The light from the document O illuminated by the lamp 4 is reflected by the mirror 5 in a direction parallel to the document placement surface of the document table, and is reflected by the lens 6.
be oriented towards. The lens 6 forms an optical image of the document on the light-receiving surface of the CCD 7, on which a large number of point-like light-receiving elements are arranged in a row. The CCD 7 self-scans this image in the direction in which the light-receiving elements are arranged, and forms an electric signal corresponding to the image. A desired image is printed out using this signal.

The movable carriage 3 is mounted on a movable base 8 so as to be movable in the X direction (the left-right direction in FIG. 2, which is a direction parallel to the document placement surface of the document table 1). That is, 9 is a sliding bearing fixed to the carriage 3, and this bearing 9 is slidably fitted to a linear guide rail 10 fixed to the movable base 8. The rail 10 is oriented in the X direction. Therefore, if the stand 8 is stopped, the carriage 3 will be guided by the rail 10
It is movable in the direction.

The carriage 3 is also movable in the Y direction (the left-right direction in FIG. 1, that is, the direction perpendicular to the X direction, and this direction is also parallel to the document placement surface of the document table 1). In detail, a sliding bearing 11 is fixed to the movable base 8, and this bearing 11 is attached to the linear guide rail 1 fixed to the box 2 of the main body of the device.
2 is slidably fitted. rail 1
2 is oriented in the Y direction. Therefore, the carriage 3 is stopped with respect to the platform 8, and the carriage 3 is stopped with respect to the platform 8.
If you move it in the Y direction under the guide of the rail 12,
The carriage 3 moves in the Y direction.

Now, the arrangement direction of a large number of light receiving elements of the CCD 7 is made to correspond to the Y direction. In other words,
When each light-receiving element of the CCD 7 is projected onto the document placement surface of the document table 1 by the lens 6 and mirror 5, the projected images of each light-receiving element are aligned in a line in the Y direction. Δl in Figure 1
is the array length of the above-mentioned large number of light-receiving element projection images, in other words, an image of a very narrow portion of the document O having a length of Δl is imaged on the light-receiving element array of the CCD 7 at one time,
It is converted into an electrical signal. Then, the carriage 3 is guided by the rail 10 as described above.
is moved in steps in the direction. In other words, it moves while repeating an operation of moving a predetermined minute distance in the X direction and stopping for a predetermined short time. And at the above stop
The CCD self-scans and reads a very narrow portion of the document with a length of Δl. When this reading is completed, the carriage 3 moves in the X direction by the predetermined minute distance, and this minute distance is set in accordance with the resolution required for the image to be reproduced. As above, move the carriage 3 to
When reading from one end to the other end in the X direction of an area with a width of Δl of the document O is completed, the carriage 3 is moved backward in the X direction, and then moved a distance of Δl in the Y direction, or Or, first move the distance Δl in the Y direction, then move back in the X direction, and then
By moving it forward in the X direction again as described above, an area having a width of Δl adjacent to the document area that has been read is read from one end to the other end in the X direction. After repeating this operation and reading the entire document O from one end to the other in the Y direction and from one end to the other in the X direction, the carriage 3 returns to the original in both the X and Y directions. and return to the initial starting position. When the carriage 3 moves in the Y direction, the CCD does not self-scan, and the document is not read.

Incidentally, the signal obtained by reading a very narrow width part of the document having the length Δl is sent to the printer as the carriage 3 moves forward in the X direction, and the image is simultaneously generated. Alternatively, the above signal may be transmitted to the memory circuit as the carriage 3 moves forward in the X direction, and the
Information regarding an area with a width of Δl from one end to the other in the direction is temporarily stored in a memory circuit, and is transmitted to the printer while the carriage 3 is moving back in the X direction and reading the document area adjacent to the above area. Alternatively, the signal may be transmitted to a memory circuit as the carriage 3 moves two-dimensionally to temporarily store information on the entire surface of the document in the memory circuit, and then read the entire surface of the document. After completion, the desired image may be transmitted to a printer and printed out. In the above example, the backward movement speed in the X direction and the movement speed in the Y direction of the carriage 3 are faster than the forward movement speed in the X direction, which reduces the time required to read the entire document surface. is shortened. Alternatively, move the carriage 3 forward in the X direction to read an area with a width of Δl from one end of the document in the
The carriage 3 is moved forward a distance of Δl in the X direction, and then the carriage 3 is moved backward in the same step movement as in the forward movement. Repeat this movement, and during this return movement also during the short stop mentioned above.
The original may be read by scanning the CCD by itself. In any case, the movable reading head constituted by means 3 to 7 only needs to read a small area, such as a document, at a time, so it is small and lightweight, and can be moved reliably in steps.

Next, a mechanism for moving the carriage 3 in the X direction and the Y direction will be explained. The mechanism described below is 1
It is possible to move the carriage 3 in both the X direction and the Y direction with the flexible indexing member of the book, and there is no need to mount a motor for moving the carriage 3 on the stand 8 or the carriage 3, and therefore these movable objects It is possible to reduce the weight of the machine and improve the accuracy of movement.

In FIG. 3, 13 to 17 are timing pulleys. The pulley 13 is fixed to the output shaft of a pulse motor 19 that can rotate in both forward and reverse directions. The pulley 14 is rotatably arranged in a fixed position.
The pulleys 13 and 14 are arranged so as not to mechanically interfere with the table 8, and are therefore preferably arranged further outside of both ends of the movement range of the table 8 in the Y direction. Pulley 15, 16, 17
are each rotatably mounted on a shaft fixed to the stand 8. The pulleys 15 and 17 are arranged on one side of the table 8 in the X direction, and the pulley 16 is arranged on the other side. Pulley 15, 17,
The pulley 16 is arranged so as not to mechanically interfere with the movement of the carriage 3 on the platform 8. Therefore, the pulleys 15, 17, and 16 are arranged further outside the movement range of the carriage 3 in the X direction. It is preferable that the 18 is a substantially endless timing belt with pulleys 13, 15, 16, 1
7 and 14 in that order. Pulley 13,
between pulleys 17 and 14; between pulleys 14 and 15; between pulleys 17 and 14;
Between the pulleys 13 and 13, the belt 18 is stretched parallel to the rail 12, in other words, in the Y direction.
The belt 18 is stretched parallel to the rail 10 between the pulleys 16 and 16 and between the pulleys 16 and 17, in other words, in the X direction. The belt 18 is fixed to a hanging plate 22 fixed to the carriage 3 between the pulleys 15 and 16. (See Figure 1). Pulley 16, 17
The belt 18 may be fixed to the hanging plate 19 between the two ends.

In FIG. 1, 20 is an electromagnet, which is fixed to the carriage 3. When the electromagnet 20 is activated, it is attracted to the magnetic guide rail 10 and the carriage 3 is moved to the stand 8.
Fixed so that it does not move relative to. Further, in FIG. 2, 21 is an electromagnet, which is fixed to the movable table 8. When the electromagnet 21 is activated, it is attracted to the magnetic guide rail 12, and the table 8 is moved against the rail 12.
In other words, it is fixed so that it does not move relative to the main body of the reading device.

Now, when the reading switch is turned on, the electromagnet 21 is activated and the table 8 is fixed in an immovable state. However, since the electromagnet 20 is not activated, the carriage 3 remains movable relative to the platform 8. Next, the pulse motor 19 is operated to drive the pulley 13 to rotate intermittently in the counterclockwise direction. As a result, the carriage 3 moves forward (step movement) in the X direction as described above, and an area of width Δl of the document is read from one end to the other end in the X direction as described above. When this reading is completed, the rotation direction of the motor 19 is reversed while the magnet 21 is activated and the magnet 20 is not activated, the pulley 13 is rotated clockwise, and the carriage 3 is moved back in the X direction, returning to the forward movement starting position. Bring it back. When the carriage 3 returns to the original forward movement starting position, the motor 19
stops once, the magnet 21 is deactivated, and the stand 8
is movable along the rail 12, and the magnet 20 is actuated to fix the carriage 3 to the base 8. In this state, when the motor 19 is operated and the pulley 13 is rotated counterclockwise, the stand 8 moves forward in the Y direction with the carriage 3 stopped above it, and when the stand 8 moves forward a distance Δl, the motor 19 is stopped. At the same time, the magnet 21 is activated and the magnet 2
0 is inactive and the above operation can be repeated again.
After the entire document has been scanned, the carriage 3
moves back in the X direction and returns to the forward movement starting position at the last reading operation, then the magnet 21 is deactivated, the magnet 20 is activated, the motor 19 rotates the pulley 13 clockwise, and the table 8 is rotated. With the carriage 3 fixed thereon, it is moved back in the Y direction to return the carriage 3 to the forward movement starting position at the time of the first reading. In the above operation, when the carriage 3 moves backward in the X direction, and when moving back and forth in the Y direction, the pulses applied to the motor 19 are lower than when the carriage 3 moves forward in the X direction. By making the pulse interval of the voltage shorter, thereby making the rotational speed of the pulley 13 faster in the former case than in the latter case, the carriage 3 can be moved back and forth in the X direction and back and forth in the Y direction. The speed of the movement is made faster than the forward movement speed in the X direction as described above.

In the above-mentioned operation, when the forward movement of the carriage 3 in the X direction is completed, the carriage 3 is moved backward and then moved forward by Δl in the Y direction. However, when the forward movement of the carriage 3 in the X direction is completed, the magnet 21 is Then, the magnet 20 is activated to rotate the pulley 13 counterclockwise to move the table 8 forward in the Y direction by Δl, and then the magnet 21 is activated again, the magnet 20 is deactivated, and the pulley 13 is rotated clockwise. The carriage 3 may be rotated to move the carriage 3 backward in the X direction. At this time, if the pulse interval of the pulse voltage applied to the motor 19 is the same as that when the carriage 3 moves forward, and the document is read as described above when the carriage 3 moves backward in the X direction, the entire surface of the document can be read. Time is further reduced.

Although a pulse motor is used as the motor 19 in the above example, a DC motor can also be used as the motor 19, and the rotation angle of this DC motor can also be controlled using an encoder connected to the motor shaft. .

Further, in the above example, magnets 20 and 21 were used as means for fixing the carriage 3 to the stand 8 and the stand 8 to the rail 12, respectively.
Instead of 1, the following means can also be adopted. That is,
An electromagnetic clutch is interposed between the pulley 16 and its support shaft 16', and when the clutch operates, the pulley 16
is non-rotatably fixed to the fixed shaft 16' and is rotatable when the clutch is inactive. on the other hand,
The sliding load of the platform 8 on the rail 12 is made larger than the sliding load of the carriage 3 on the rail 10. Thus, when the electromagnetic clutch is inactive, if the pulley 13 is rotated in the forward or reverse direction, the carriage 3 will reciprocate on the platform 8 while the platform 8 is stopped relative to the rail 12, and the electromagnetic clutch will be actuated to rotate the pulley 13 in the opposite direction. 13 is rotated in forward and reverse directions, the carriage 3 is fixed to the table 8 and the table 8 moves back and forth. Thus, the electromagnetic clutch is turned on and off at the same time as the magnet 20.

In the above example, a substantially endless belt 18 (both ends of one end belt may be connected to the hanging plate 22) is stretched to form a T-shaped closed loop, and In this example, the carriage 3 is moved two-dimensionally without installing a motor in either the carriage 3 or the carriage 3.

Further, in the above example, a wire may be used instead of the timing belt, and a normal wire pulley may be used instead of the timing pulley.

Furthermore, a so-called area type CCD can also be used as the CCD.

In addition to the usual monocular lens, the lens in the above example includes multiple small-diameter imaging elements such as a bar lens and a converging light transmitter (self-occurrence product name) in a single row.
It is also possible to replace the imaging optical system with an imaging optical system bundled in a plurality of arrays.

As described above, according to the present invention, the reading carriage can be moved in the X direction and the Y direction using one drive motor, and the cost of the apparatus can be reduced by eliminating the need for an expensive drive motor.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the main part of the embodiment of the present invention as seen in the X direction, Fig. 2 is an explanatory diagram of the main part of the embodiment as seen in the Y direction, and Fig. 3 is an explanatory diagram of an example of the carriage moving mechanism. FIG. 1 is a fixed document table, 3 is a carriage, 6 is a lens, 7 is a CCD, 8 is a movable table, 10 and 12 are guide rails, 13 to 16 are timing pulleys, 18
1 is a timing belt, and 19 is a motor.

Claims (1)

[Scope of Claims] 1. A reading carriage for reading a document, a first guide member for guiding the movement of the reading carriage in a first direction, a movable base on which the reading carriage and the first guide member are mounted, and a movable base for mounting the reading carriage and the first guide member. a second guide member that guides movement of the movable base in a second direction orthogonal to the first direction, and an operation of moving the reading carriage in the first direction and an operation of moving the movable base in the second direction. In a document reading device that reads a document by repeatedly performing the above steps, a drive motor for moving the reading carriage and the movable base; a driving force transmitting member that extends along the second guide member and forms a closed loop; a first inhibiting means that inhibits movement of the reading carriage in the first direction; a second prohibition means for prohibiting movement in two directions, and the reading carriage is moved in the first direction by actuating the second prohibition means and moving the drive force transmission member by the drive motor. . A document reading device, wherein the movable table is moved in a second direction by activating the first inhibiting means and moving the driving force transmitting member by the drive motor.