JPH01189279A - Optical image reader - Google Patents

Abstract

PURPOSE:To execute color discrimination with a microdot, to improve accuracy and to cause a manufacturing cost to be inexpensive by arranging different kinds of light-emitting elements at the base edges of light-emitting fibers and causing the reciprocating quantity to be integer-fold or above of a pitch interval between respective light-emitting fibers. CONSTITUTION:For light-emitting fibers TYi and TRi, light-emitting elements LY1 and LY2 to emit a yellow wavelength light and light-emitting element LR1-LRns to emit a red wavelength light are alternately arranged every other line, light-emitting fibers RYi and RRi arranged corresponding to the light- emitting fibers are made into one group for plural lines, and they are connected to one light-receiving element PY and PR. A head supporting plate 14 to support an image reading head 3a is draw-energized through a spring 15 to a frame 1b of one side, a cam follower 16 is project-provided to the head supporting plate 14, on the other hand, an eccentric cam disk 18 is shaft-mounted to a rotary shaft 17 at one side of the frame 1b, and an eccentric distance between the center of the eccentric cam disk 18 and the center of the rotary shaft 17 is made to coincide with a pitch interval (a) of respective light-emitting fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device suitable for optically reading images of color originals.

[Prior Art] FIG. 1 shows an example of this type of optical image reading device. Although the illustrated apparatus is of a shuttle type, an image reading head 3 is disposed opposite to the front side of a platen roller 2 supported between frames 1a and 1b.
is configured to reciprocate in the axial direction of the platen roller 2 by driving the motor 4. As shown in FIG. 5, the image reading head 3 used in this device includes a large number of light emitting fibers Ti (i=an integer from 1 to n) and
and a number of light receiving fibers Ri corresponding to each light emitting fiber 1.
(i=an integer of 1 to n), and the light emitting fiber Ti
When light from each light-emitting element Li (i = an integer from 1 to n) is irradiated onto the document Y through The light is received by each light receiving element p*<i=an integer from 1 to n) through the light receiving fiber Ri. Then, an electric signal outputted from each light receiving element Pi according to the amount of received light is transmitted to each amplifier Ai.
(an integer from i-1 to n) is amplified and compared with a predetermined threshold value in each discrimination circuit Gi (i=an integer from 1 to n) in the next stage. It is determined whether the color is solid or black.

On the other hand, in the case of an image reading device with a color discrimination function for color images, FIG. 6 shows a schematic configuration of the main parts of the image reading head 3. A light emitting diode (LED) L that emits light with a wavelength of
Light emitting diodes (LEDs) LRi that emit red (R) wavelength light are arranged in pairs, respectively. In this case, at each movement point of the reading head 3, the light emitting element LYi (
or LRi> and the light emitting element LRi (or LY i>) in order. Then, the eight light emitting elements t-yi.

One light emitting fiber T that is shared by the light emitted from LRl
i, and the reflected light is received by the light receiving element Pi via the light receiving fiber R1 (not shown). Therefore, from each light receiving element Pi, this yellow (Y)
) and red (R), and the electrical signals are compared with a predetermined darkness value in each discriminator circuit Gi.
If both of the electrical signals in R) are at a lower level than a predetermined threshold, the color is black, conversely, if both are at a high level, the color is white, and if one is low and the other is high, the color is red. A determination is made.

[Problems to be Solved by the Invention] However, according to such a conventional optical image reading device, each light emitting fiber Ti of the image reading head 3 has a plurality of light emitting elements (in the above example, both light emitting elements Ly;
LR+) are arranged, so the number of inputs into each light emitting fiber Ti is halved, and if the diameter of the light emitting fiber is increased to increase the amount of light, color discrimination from minute dots will be hindered. . In particular, three light emitting elements (for example, yellow (Y), red (R), and blue (B) are added).

), this problem becomes even bigger. On the other hand, due to manufacturing reasons, a light emitting element Ly+ is placed at the base end of each light emitting fiber.

There is also the problem that manufacturing costs are high due to difficulty in accurately arranging the LRl.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and its purpose is to provide an optical image reading device having a high-performance color discrimination function at a low cost. is.

[Means for Solving the Problems] In order to achieve this object, an image reading device of the present invention has an image reading head and a platen disposed facing each other, and the image reading head has a plurality of light emitting fibers connected to the platen of a head base. They are arranged in rows at equal intervals at the end of the surface facing the surface, and the same number of light receiving fibers are arranged in pairs corresponding to each of the light emitting fibers, and multiple types of wavelength light are arranged at the same wavelength. Different types of light emitting elements are arranged correspondingly at the base end of each light emitting fiber so that the light is emitted from the end of the surface opposite to the platen surface of each light emitting fiber at equal pitch intervals, and the image reading head is provided with different types of light emitting elements. A driving source is connected so as to be able to reciprocate in the direction in which each of the light emitting fibers is arranged, and a linking mechanism between the driving source and the image reading head allows the amount of reciprocating movement of the image reading head to be adjusted between each of the light emitting fibers. The gist is that a movement amount control means is provided so that the amount of movement is an integral multiple or more of the pitch interval.

[Function] With such a configuration, according to the image reading device of the present invention, the reading head reciprocates the color document surface on the platen in the direction in which the light emitting fibers are arranged, and at this time, the light emitted from the tip of each light emitting fiber is emitted from the end of the light emitting fiber. The light emission timing of each light emitting element is controlled so that light of different wavelengths is irradiated onto the same reading point on the surface of the color document in an overlapping manner. Then, light of different wavelengths at the same reading point on the surface of the color original is detected through the light receiving fiber, and the desired color can be discriminated from the amount of the received light.

[Example] An example of the present invention will be described below with reference to the drawings. FIG. 2 shows a shuttle type image reading head used in the optical image reading apparatus of the present invention. The illustrated image reading head 3a has a large number of light emitting fibers T1. T2...Tn are arranged in rows at equal intervals, and the same number of light receiving fibers R1, R2...Rn are arranged in pairs corresponding to the eight light emitting fibers, and a head cover is placed above them. covered by 12. Further, a printed circuit board 13 is attached to one flat plate surface 11b of the head base 11, and a light emitting element consisting of a photodiode is fixed to the printed circuit board 13 corresponding to the base end of the light emitting fiber, and the light receiving element is fixed to the printed circuit board 13 in correspondence with the base end of the light emitting fiber. A light receiving element is fixed corresponding to the base end of the fiber. To explain this in more detail, in the present invention, every other light emitting fiber is colored yellow (
A light emitting element LY1.Y) that emits light with a wavelength of LY2...
・A light emitting element I R1 that emits red (R) wavelength light.
LR2... are arranged alternately. On the other hand, yellow (Y
) is a light-emitting fiber TY1. TY2...
A plurality of light-receiving fibers arranged corresponding to ... are combined into one and connected to one light-receiving element PY, and a light-emitting fiber TR that emits red (R) wavelength light
I.

A plurality of light-receiving fibers arranged corresponding to TR2... are also combined into one and connected to one light-receiving element PR. In this case, the former light-receiving element PY is a photodiode with excellent sensitivity to yellow (Y) light, and the latter light-receiving element PR is a photodiode with excellent sensitivity to red (R) light.

The configuration of an optical reading device to which this image reading head 3a is applied is the same as that shown in FIG.
A head support plate 14 supporting the frame 11a is pulled and biased by one frame 11a via a spring 15, and a cam follower 16 is protruded from the head support plate 14, while a rotation shaft 17 is attached to one side of the frame 11a. An eccentric cam disk 18 is pivotally attached, and the cam follower 16 is attached to the circumferential surface of the cam disk 18.
are in sliding contact so as to resist the traction force of the spring 15. In this case, the eccentric distance between the center of the eccentric cam disc 18 and the center of the rotating shaft 17 is
TY2. TR2, TY3... Matches the pitch interval a of TYn and TRn. Incidentally, the rotating shaft 17 and the motor 4 serving as a drive source are linked by a driven gear 20 that is pivotally attached to the rotating shaft 17 meshing with a driving gear 19 of the motor 4. Further, an encoder 21 having a pulse code surface in which a large number of slit grooves are radially opened is mounted on the rotating shaft 17, and a projector and a light receiver (not shown) are arranged opposite to each other with the pulse code surface in between. The light receiver detects the pulse frequency when the light from the projector is transmitted through or blocked by the slit groove on the pulse code surface at regular intervals as the encoder 21 rotates. Then, in synchronization with this detection signal, each of the light emitting elements LY1.
LR1, LY2. LR2, LY3...LYn, L
The structure is such that the light emission timing of Rn is controlled.

However, in the optical reading apparatus configured in this manner, the amount of movement of the image reading head 3a, which reciprocates in the axial direction of the platen roller 2 when the motor 4 is driven, is equal to the amount of eccentricity of the eccentric cam disk 18. It becomes double, that is, 2a maximum. Therefore, now the amount of movement of the reading head 10 is -a, ±0. ten a
Yellow (Y) or red (R) wavelength light is emitted from each light emitting fiber toward the Y surface of the document at three points. The order in which this wavelength light is emitted is that the light emitting fibers TYI and TR1 are emitted first, then TY2 and TR1 are emitted.
2 follows. Then, for example, if yellow (Y) light is irradiated onto a certain point on the document Y surface when the amount of movement of this reading head 3a is -a, this reading head 3a will move and the amount of movement will be -a. When it becomes O, the previous point will now be irradiated with red (R) light. Therefore, at each reading point on the original iY surface, yellow (Y
) light and red (R) light are sequentially irradiated.

As a result, yellow (Y) light and red (R) light are transmitted to the light receiving element P.
Each of the Y and PR lights are received, and as in the conventional case, the lights are converted into electrical signals and the colors are determined by comparing them with predetermined threshold values. Once one line has been read, the platen roller 2 is driven to move the document Y by the next one line, and the same operation is repeated.

Thus, in the present invention, the image reading head 3a is connected to each light emitting fiber TY1. TR1, TY2.
By reciprocating in the direction in which TR2... is arranged, it is possible to irradiate the same point on the document surface with light of different wavelengths in a superimposed manner, thereby making it possible to perform the desired color discrimination. In the above embodiment, the amount of movement of the image reading head is -a, ±
The case where color discrimination is performed at three points, Q and +a, has been described, but the discrimination points can be set to -a, -a/2, etc., for example. ±Q, +a/
2. By increasing the number of discrimination points such as +a, it is possible to discriminate colors in even finer divided areas. In addition, in the above embodiment, a light emitting element LY or LR is arranged in each light emitting fiber, and a plurality of light receiving fibers are connected together to a 1 g light receiving element PY or PR, but by reversing this, the light emitting fiber is Combine multiple pieces into one light emitting element LY or L
R, and the receiving fiber RY1. RR1,RY2. P
R2...RYn and RRn each have a light receiving element P.
It is also possible to arrange Y or PR. In this case, light is emitted simultaneously from each light emitting fiber, and each light receiving element PY
, PR can receive the light simultaneously, so the speed of color discrimination can be greatly increased.

In addition, this time we explained the photodetector separately into one for yellow (Y) and one for red (R), but if you use a photodiode with good sensitivity for both yellow and red light, one type of photodiode can be used. The light can be received by the light receiving element, and the light can be received without selecting the light to be received.

On the other hand, as shown in Figure 4, yellow (Y) light, red (R
) In addition to blue (B) light, if three types of light are used, more multi-stage color discrimination is possible and color discrimination close to full color is performed. In this case, the amount of movement of the reading head is three times the distance between each light emitting fiber! (3a) may be used.

Note that although the shuttle method has been described in the above embodiment, it goes without saying that it can also be applied to a serial method.

[Effects of the Invention] As described in the embodiments above, according to the image reading device of the present invention, a sufficient amount of light is ensured without increasing the diameter of each light emitting fiber, making it possible to distinguish colors from minute dots. The accuracy is extremely good. Furthermore, problems related to layout design of each light emitting element and light receiving element can be solved, and manufacturing costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of an image reading device according to an embodiment of the present invention, Fig. 2 is an exploded perspective view of a reading head used in this device, Fig. 3 is an explanatory diagram of the operating state, and Fig. 4 is An explanatory diagram of the operating state of an image reading head according to another embodiment of the present invention, FIG. 5 is an electrical control block diagram of a conventional image reading head, and FIG. 6 is a main part of a conventional image reading head with a color discrimination function. FIG. In the figure, 2 is a platen, 3a is an image reading head, 4 is a motor, 11 is a head base, TYi is a yellow (Y) light emitting fiber, TR: is a red (R) light emitting fiber, RY
l is yellow (Y) receiving fiber, RRl is red (R
＞ light receiving fiber, LY is a yellow (Y) light emitting element,
LR is a red (R) light emitting element, PY is yellow (Y)
A light receiving element, PR is a red (R) light receiving element, and Y is a document.

Claims (1)

[Scope of Claims] An image reading head and a platen are arranged to face each other, and the image reading head has a plurality of light emitting fibers arranged in rows at equal intervals at an end of a surface of the head base opposite to the platen surface, and The same number of light receiving fibers are arranged in pairs corresponding to each of the light emitting fibers, and the plurality of types of light having the same wavelength are arranged at equal pitch intervals and facing the platen surface of each of the light emitting fibers. Different types of light emitting elements are arranged correspondingly at the base end of each light emitting fiber so that light is emitted from the surface end, and a driving source is connected to the image reading head so that it can freely reciprocate in the direction in which each light emitting fiber is arranged. In addition, the linkage mechanism between the drive source and the image reading head is provided with movement amount control means such that the amount of reciprocating movement of the image reading head is an integral multiple or more of the pitch interval between the light emitting fibers. An optical image reading device characterized by: