JPH0537578Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a color document reading device, and more particularly, to a color document reading device that performs color separation by reciprocating a color filter attached to the bobbin of a voice coil type linear motor. .

(Prior Art) Recently, with the diversification of information, the use of color information in office equipment such as personal computers has rapidly increased, and there is a demand for input devices for color originals. Therefore, a color document reading device has been developed as a color document input device.

Such a color document reading device stores the image information of the document in three primary colors (Yellow, Magenta, Cyan).
A color separation means is provided for separating the light into each color component and introducing the light of each color component to the line image sensor. Although there are various methods for this color separation means, the one that can color separate the image information for each line read from the original and can be miniaturized is a color filter installed on the optical path. There are methods for color separation by reciprocating movement, among which a color separation means using a voice coil type linear motor as shown in FIG. 6 has been proposed.

In FIG. 6, 1 is a color separation means, which includes a lens 2 into which reflected light from the document surface is introduced, and a line image sensor that photoelectrically converts the image formed by the lens 2. 3 and lens 2
and a filter body 4 disposed on the optical path between the line image sensor 3 and the line image sensor 3. Filter body 4
has a red filter 5 and a green filter 6 in a stripe pattern.
and blue filters 7 are arranged at predetermined intervals,
The filter body 4 is fixed to the upper part of a bobbin 9 of a voice coil type linear motor (hereinafter referred to as a linear motor) 8. At the bottom of the bobbin 9 is a coil 10.
The coil 10 is arranged in the magnetic circuit section of the linear motor 8, which is composed of a magnet 11 and a yoke 12. On the other hand, one end of a pair of leaf springs 13 and 14 is fixed to both sides of the upper end and both sides of the lower end of the bobbin 9, respectively, and the other end of the leaf springs 13 and 14 is fixed to a bracket 15.
are fixed to the upper and lower ends of the The bobbin 9 is held by the leaf springs 13 and 14 so as to be able to reciprocate in the vertical direction in the figure, and when the bobbin 9 is not in operation, the edge filter 6 of the filter body 4 is located on the optical path from the lens 2, and the bobbin 9 When activated, the three color filters are sequentially positioned on the optical path due to the reciprocating movement of the bobbin 9. The bobbin 9 moves in the vertical direction as the magnitude and direction of the electromagnetic force acting on the bobbin 9 change as the magnitude and direction of the drive current supplied to the coil 10 from a drive circuit (not shown) change. This allows the line image sensor 3 to read the reflected light (image information) from the document surface for each color component.

(Problem to be solved by the invention) However, in such a conventional color document reading device, the bobbin 9 is attached to the leaf springs 13 and 14.
Since the color document reader is supported movably in a predetermined direction (up and down), when the color document reader is transported or the color document reader is not used for a long period of time, the bobbin may be moved by an external force acting on the color document reader. There was a risk that the color separation means 1 would be damaged or the leaf springs 13 and 14 would be deformed due to large fluctuations in the color separation means 1.

Therefore, conventionally, when transporting the color document reading device, the bobbin 9 has been fixed with metal fittings, sponge, or the like. However, the method used for such metal fittings and sponges not only makes it difficult to attach and remove the metal fittings and sponges, resulting in poor work efficiency, but also is wasteful as the metal fittings and sponges are no longer needed after transportation. Furthermore, when the color document reading device is not used for a long period of time, it is common practice to reinstall the metal fittings and sponge, and in this case, there is no practical use in preventing deformation of the leaf springs 13 and 14.

(Purpose of the invention) Therefore, the present invention provides a short-circuit circuit that short-circuits the coil of a voice coil type linear motor, and a switching means that selectively switches the coil between the drive circuit and the short-circuit. By connecting the coil to a short circuit using a switching means when transporting the device or not using it for a long time, if the position of the coil changes, the current generated in the coil due to electromagnetic induction and the magnetic field will be reduced. To provide a color document reading device that can suppress the positional fluctuation of a coil by electromagnetic force, suppress the fluctuation of the bobbin, and prevent damage to color separation means and deformation of a leaf spring simply by switching using a switching means. The purpose is

(Structure of the invention) In order to achieve the above object, the invention provides a line image sensor that decomposes incident light into a plurality of pixels and converts it photoelectrically, and a light introducing means that introduces reflected light from a document into the line image sensor. and a filter body provided in the optical path introduced into the line image sensor by the light introducing means and having a plurality of different color filters arranged in a stripe shape in a predetermined movement direction, and a bobbin to which the filter body is attached. a voice coil type linear motor, the voice coil type linear motor is provided with a plate spring that supports the bobbin so as to be movable only in a predetermined movement direction, and a plate spring that is wound around the bobbin and placed and supplied in a magnetic field. A color document reader comprising a coil that changes the position of the bobbin in the predetermined movement direction by changing the current value, and a drive circuit that drives the bobbin by supplying the coil with a current whose magnitude and direction change. In the apparatus, a short-circuit circuit that short-circuits outlet ports at both ends of the coil; a switching means that selectively connects the short-circuit circuit and the drive circuit to the coil;
It is characterized by having the following.

Hereinafter, the present invention will be explained in detail based on embodiments.

1 to 4 are diagrams showing an embodiment of the present invention.

In FIG. 1, reference numeral 21 denotes a color document reading device, and a main body 21a of the color document reading device 21 includes a document presser 22, a document table 23, and an image reading means 2.
4 is provided.

The document presser 22 covers the entire surface of the document table 23, and one end thereof is rotatably supported by the main body 21a, and brings the set document into close contact with the document table 23. A glass plate is used as the document table 23, and is provided in a shape that closes an opening 21b at the top of the main body 21a.

The image reading means 24 includes a light source 31, mirrors 32, 3
3, 34, slit 35, carriage 36, 3
7, a lens 38, a color separation means 39, a line image sensor 40, etc., and reads the image information (color data) of the original (color original) set on the original platen 23.

The light source 31 is, for example, a fluorescent lamp, and emits light over the entire reading width of the document. light source 31
The light emitted from the mirror 3 is reflected on the document surface and
After being reflected by mirrors 33 and 34, the light passes through a slit 35 and is introduced into a lens 38. The light source 31 and mirror 32
is mounted on the carriage 36, and the mirror 33
and mirror 34 are mounted on a carriage 37. The carriages 36 and 37 are provided so as to be able to reciprocate in the direction of arrow P from the position shown in FIG. . Here, the moving amount and moving speed of the carriage 37 gradually lag behind the carriage 36. This amount of delay increases as the amount of movement of the carriage 36 increases, and the maximum amount of movement of the carriage 37 is approximately half that of the carriage 36. Therefore, regardless of the movement of the document reading position, the mirrors 32 and 3
The optical path length of the light reflected by the lenses 3 and 34 and introduced into the lens 38 through the slit 35 is always constant. Therefore, the line image sensor 40
An image can be formed with a constant focus on the top.

As shown in FIG. 2, the color separation means 39 is configured such that the light from the lens 38 passes through a filter body 41 and is introduced into the line image sensor 40, and the filter body 41 is a voice coil type linear motor. (hereinafter referred to as a linear motor) 42 is fixed to the upper part of a bobbin 43. Bobbin 4
A coil 44 is wound around the lower part of the coil 44, and when a predetermined current is passed through the coil 44, the bobbin 43 is driven according to the direction and magnitude of the current.
On the other hand, one ends of a pair of leaf springs 45 are fixed to both sides of the upper end of the bobbin 43, and one ends of a pair of leaf springs 46 are fixed to both sides of the lower end of the bobbin 43. The other ends of the leaf springs 45 and 46 are fixed to the upper and lower ends of a bracket 47, respectively. The leaf springs 45 and 46 are provided facing each other with the bobbin 43 in between, and the bracket 4
The bobbin 43 is moved back and forth (up and down) with the fixed end on the 7 side.
hold possible. Therefore, when a predetermined current is applied to the coil 44, the bobbin 43 held by the leaf springs 45 and 46 is driven in the vertical direction as shown by the arrow in FIG. 41 reciprocates in the right angle direction. In addition, leaf spring 4
Reference numeral 5 is made of a conductor, and by fixing the lead end of the coil 44 and the lead wire from the motor drive circuit 51 to the plate spring 45, a current can flow through the plate spring 45 to the coil 44.

The bobbin 43 is disposed within a magnetic circuit of a linear motor 42 composed of a yoke 48 and a magnet 49. That is, as shown in FIG. 3, the yoke 48 is formed into an E-shape having three arms, and magnets 49 are fixed to the insides of the two outer arms. The central arm of the yoke 48 is a bobbin 43 on which a coil 44 is wound.
has entered the lower cavity. In addition, the coil 44
The winding width on the bobbin 43 is shorter than the width of the magnet 49, and the width of the magnet 49 is set longer than the stroke width of the bobbin 43. In this way, a linear motor in which the winding width of the coil 44 around the bobbin 43 is shorter than the width of the opposing magnet 49 is generally referred to as a short coil type.

As shown in FIG. 4, the filter body 41 includes three colored filters, a red filter RF, a green filter GF, and a blue filter BF, which are spaced at predetermined intervals in the moving direction of the bobbin 43 (filter body 41). They are arranged in a striped pattern, and the filter body 41 is subjected to a light-shielding treatment (for example, coating with black paint) to block the transmission of light. Therefore, the portion of the filter body 41 that is sandwiched between the color filters RF, GF, and BF and subjected to light shielding processing constitutes a light shielding portion 41a, and the width of the light shielding portion 41a (width in the moving direction of the filter body 41) is set to a length that can completely block the light beam from the lens 38 based on the distance between the line image sensor 40 and the filter body 41.

On the other hand, as shown in FIG. 4, the line image sensor 40 includes CCDs (Charge Coupled Devices) 50, which are photoelectric conversion elements arranged in a row. It has a corresponding length. The light that has passed through the color filters RF, GF, and BF enters the CCD56, and the CCD
50 photoelectrically converts incident light to read image information.

Referring again to FIG. 3, a drive current is supplied from a motor drive circuit (drive circuit) 51 to the coil 44 of the voice coil type linear motor 42.
A short circuit 52 that shorts both terminals of the coil 44 is provided in parallel with the coil 44 . The short circuit 52 is provided with a switch 53, and when the switch 53 is closed, the coil 44 is short-circuited by the short circuit 52. The switch 53 is the color original reading device 21
It is provided in the operation section of the.

Next, the effect will be explained.

When the color document reading device 21 performs a reading operation, the switch 53 is turned off and the short circuit 52 is opened. Therefore, the coil 44 is supplied with a drive current from the motor drive circuit 51, and the bobbin 43
moves up and down. That is, the color document reading device 21 uses the image reading means 24 to main scan the document set on the document table 23, and also moves the carriages 36 and 37 in the direction of arrow P in FIG. Read information. The color original reading device 21 can read color originals and black and white originals, and when reading color originals, the filter body 41 is moved up and down and a red filter RF,
1 each for green filter GF and blue filter BF
Read three times in total.

Now, when a sine wave current is supplied as a drive current to the coil 44 from the motor drive circuit 51, the drive current flows to the coil 44 because the switch 53 is open, and the bobbin 43 moves back and forth depending on the magnitude and direction of the drive current. do. As the bobbin 43 reciprocates, each color filter RF is placed on the optical path passing through the lens 2.
GF and BF are sent sequentially and color separated.

Next, the switch 53 is turned on when transporting the color document reading device 21 or when the color document reading device 21 is not used for a long time. When switch 53 is turned on, coil 44 is short-circuited by short circuit 52 . In this state, the color document reading device 21
When an external force is applied to the bobbin 43 and the bobbin 43 moves in the vertical direction, the coil 44 cuts the magnetic field (magnetic flux) created by the magnet 49. Therefore, when the coil 44 cuts the magnetic flux of the magnet 49, an electromotive force is induced in the coil 44 by electromagnetic induction in a direction that blocks the change in the magnetic flux, and an induced current flows. Due to this induced current, the coil 44 receives an electromagnetic force in a direction opposite to the direction of movement caused by an external force, and the coil 44, that is, the bobbin 4
3 is moved in the opposite direction to the initial movement direction due to the spring force of leaf springs 45 and 46. After passing the initial equilibrium position (rest position), an electromotive force is generated in the coil 44 in the opposite direction to the previous direction, and an induced current due to this electromotive force flows in the opposite direction to the initial direction. Therefore, an electromagnetic force in the direction of the rest position acts on the coil 44 that has passed through the rest position. That is, when the bobbin 43 is moved by an external force, an induced current flows in the coil 44, and an electromagnetic force acts in a direction opposite to the direction in which the bobbin 43 moves. The electromagnetic force that acts on acts as a damping force. Therefore, the bobbin 43 receives a large damping effect in its damped vibration, and quickly stops at the initial equilibrium position (rest position). As a result, when the color document reading device 21 is transported, external force can be attenuated, and the color separation means 39 can be prevented from being damaged and the leaf springs 45 and 46 from being deformed. In particular, since it is not used with metal fittings, sponges, etc. as in the past, unreasonable force from these is not applied, and damage and deformation can be more reliably prevented. This improves work efficiency.

In the above embodiment, the short circuit 52 is turned on/off by the switch 53, but the present invention is not limited to this.
As shown in the figure, the coil 44 is connected to the motor drive circuit 5.
Alternatively, a relay 60 may be provided to selectively connect to the short circuit 52 and the short circuit 52, and the switching of the relay 60 may be linked to the power switch 61 of the color document reading device 21. That is, in FIG. 5, the normally closed contact 60a of the relay 60 is connected to the short circuit 52, and the normally closed contact 60b is connected to the motor drive circuit 51. The excitation coil 60c of the relay 60 is connected to the power supply circuit 62 of the color document reading device 21, and the power supply circuit 62 is supplied with external power via the power switch 61. Therefore, when the power switch 61 is turned on, an excitation current is supplied to the excitation coil 60c of the relay 60 via the power supply circuit 62, and the contact piece 60d of the relay 60 is separated from the normally closed contact 60a and connected to the normally closed contact 60b. be in contact with Therefore, when the power switch 61 is turned on, the coil 44 is connected to the motor drive circuit 51 and becomes operable.

On the other hand, when the power switch 61 is turned off, the excitation current to the relay 60 is stopped, and the contact piece 60d switches from the normally closed contact 60b to the normally closed contact 60a.
Therefore, the coil 44 is connected to the short circuit 52 in conjunction with the off operation of the power switch 61, and fluctuations in the bobbin 43 are suppressed.

Therefore, there is no need for an operation to switch the connection between the short circuit 52 and the coil 44 in addition to the on/off operation of the power switch 61, further improving work efficiency.

(Effects) According to the present invention, when the color document reading device is transported or not used for a long time, the coil can be short-circuited by the switching means, and fluctuations in the bobbin can be suppressed. Therefore, it is possible to prevent damage to the color separation means and deformation of the leaf spring with a simple operation.

Furthermore, compared to fixing the bobbin with conventional metal fittings or sponge, no excessive force is applied to the leaf spring or bobbin, making it possible to more reliably prevent damage or deformation of the leaf spring.

[Brief explanation of the drawing]

1 to 4 are diagrams showing an embodiment of the color document reading device of the present invention. FIG. 1 is a side cross-sectional view of the color image reading device, and FIG. A perspective view, FIG. 3 is a circuit diagram of the coil drive system of the voice coil type linear motor, and FIG. 4 is a front view showing the positional relationship between the filter body and the CCD. FIG. 5 is a circuit diagram of a drive system of a voice coil type linear motor in another embodiment of the color document reading device. FIG. 6 is a perspective view of a main part of color separation means of a conventional color document reading device. 21... Color document reading device, 24... Image reading means, 38... Lens (light introduction means), 39...
...Color separation means, 40...Line image sensor,
41...Filter body, 42...Voice coil type linear motor, 43...Bobbin, 44...Coil,
45, 46...plate spring, 50...CCD, 51...
...Motor drive circuit (drive circuit), {53...Switch, 60...Relay} (switching means), 61...Power switch.

Claims (1)

[Utility Model Registration Claims] (1) A color original reading device comprising a line image sensor which resolves incident light into a number of pixels and performs photoelectric conversion on the light, a light introducing means which introduces reflected light from an original into the line image sensor, a filter body in which a number of different color filters are arranged in a stripe pattern in a predetermined direction of movement and which is provided in a light path introduced into the line image sensor by the light introducing means, and a voice coil type linear motor having a bobbin to which the filter body is attached, wherein the voice coil type linear motor comprises a leaf spring which supports the bobbin so that it can move only in the predetermined direction of movement, a coil which is wound around the bobbin and placed in a magnetic field and which displaces the position of the bobbin in the predetermined direction of movement as the value of the current supplied thereto changes, and a drive circuit which supplies a current whose magnitude and direction changes to the coil to drive the bobbin, characterized in that the color original reading device further comprises a short circuit which shorts out the outlets at both ends of the coil, and a switching means which selectively switches between the short circuit and the drive circuit and connects the coil to the coil. (2) A color document reading device according to claim 1, wherein the switching means switches between the drive circuit and the short circuit in conjunction with the on/off of a power source for the color document reading device to connect to the coil.