JP2001127963A - Image reading device, information processing system, image reading method and computer-readable storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read a monochromatic original at higher speed and also to improve the reading quality, even when a color original is read as a monochromatic original. SOLUTION: When a color original is read, a Red-LED 21, a Green-LED 22 and a blue-LED 23 are switched and turned on in sequence, independently of each other and the color original is read three times for a single line of the sensor secondary scanning direction to obtain R, G and B image information, respectively. When a monochromatic original is read, the LEDs 21, 22 and 23 are simultaneously turned on for a single line of the sensor main scanning direction, and the monochromatic original is read only once. Under such conditions, current consumption of LEDs 21-23 is made smaller than the current that is consumed, when these LEDs are turned on in sequence to keep the power consumption within its allowable range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, an information processing system, an image reading method, and a computer-readable storage medium used for the image reading apparatus, and more particularly, to an image reading apparatus capable of reading both a monochrome original and a color original. It is suitable for use in

[0002]

2. Description of the Related Art In recent years, with the rapid spread of personal computers, images such as photographs and illustrations are read by an image reading device called a scanner, and the read image information is processed by a computer, and is printed on a postcard or paper by a printer. Applications such as output are expanding. An image read by a scanner is roughly classified into a color image such as a photograph and a monochrome image such as a document.

FIG. 9 is a sectional view of an image reading apparatus such as a scanner. Reference numeral 210 denotes a sensor array corresponding to the length of the document to be read, and reference numeral 220 denotes a lens array for forming light from the surface of the document on the sensor of the sensor array 210. Reference numeral 303 denotes a transparent member that contacts the original surface.

An illumination device 1 is composed of a light guide member and a light source 20 such as an LED disposed on the side of the end of the light guide member, and is configured to guide the light emitted from the light source 20 in the document surface direction. I have. As the light source 20, LEDs that emit light of three colors, red, green, and blue, respectively, are used. Here, the sensor array direction of the sensor array 210 is defined as a sensor main scanning direction, and the document feeding direction is defined as a sensor sub-scanning direction.

When reading a color original, the LED for emitting three colors of red, green and blue is sequentially switched for one line in the sensor sub-scanning direction to illuminate the original, and light information from the original is transmitted to the sensor array. The signals are converted into color electric signals by 20 sensors.

When reading a monochrome original, the original is illuminated by sequentially switching the LEDs that emit light of three colors, red, green, and blue. One line in the sensor sub-scanning direction is red, green, or blue. By using only one color of illumination, the reading speed is three times faster than when reading a color original.

[0007]

In the above-mentioned prior art, when reading a monochrome document, one line in the sensor sub-scanning direction is illuminated with only one of red, green, and blue to read a color document. The reading speed is set to be three times the reading speed. On the other hand, on the printer side that outputs an image, the output speed in monochrome is overwhelmingly higher than the output speed in color. Therefore, even if the speed of reading a monochrome document is increased as described above, it is still slower than the output speed of the printer in monochrome, and when these image reading devices and the printer are used as a system, the requirements as a system are required. Sometimes I was not satisfied with the speed.

In the above-mentioned conventional example, even when a color original is read as monochrome, light information is obtained by illumination of only one of red, green and blue for one line in the main scanning direction of the sensor. The dropout color was different for each line, and good image reading could not be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to further increase the speed of reading a monochrome document, and to obtain a good image reading even when reading a color document as monochrome. The purpose is to enable.

[0010]

First, an image reading apparatus according to the present invention comprises a plurality of light sources each emitting light of a different wavelength, illumination means for irradiating a document, and sensor means for performing photoelectric conversion. When simultaneously turning on a plurality of light sources of the illuminating means and an optical means for imaging light from the original on the sensor means, the light conversion rate of at least one of the plurality of light sources is different. Control means for supplying a current value higher than the light conversion rate of the light source to the plurality of light sources.

Secondly, the control means is characterized in that, when the plurality of light sources are simultaneously turned on, a current value supplied to at least one of the plurality of light sources is reduced. Third, the plurality of light sources of the illuminating means emit light of wavelengths corresponding to red, green, and blue, respectively.
D is characteristic. Fourth, the red, green,
At least one of the LEDs that emit light having a wavelength corresponding to blue is characterized by being made of InGaN.
Fifth, it is characterized in that signal processing means for processing and transmitting image information obtained by the photoelectric conversion by the sensor means is provided.

Sixth, an information processing system according to the present invention includes any one of the above image reading apparatuses and an information processing apparatus for processing image information obtained by the image reading apparatus. It is characterized by points.

Seventh, the image reading method according to the present invention comprises the steps of: irradiating a document with a plurality of light sources each emitting light of a different wavelength; and obtaining image information by photoelectrically converting the light from the document. And supplying a current value to the plurality of light sources such that the light conversion rate of at least one of the plurality of light sources is higher than the light conversion rate of the other light sources when the plurality of light sources are simultaneously turned on. This is characterized by having the following.

Eighthly, the computer readable storage medium of the present invention provides a procedure for irradiating an original with a plurality of light sources each emitting light of a different wavelength, and a method for photoelectrically converting the light from the original to image information. And the step of obtaining, when simultaneously lighting the plurality of light sources, a current value at which the light conversion rate of at least one of the plurality of light sources is higher than the light conversion rate of the other light sources to the plurality of light sources. It is characterized in that a program for executing the supplying procedure is stored.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a flatbed scanner. Reference numeral 200 denotes an image sensor, which converts light information from a document into an electric signal. Also, 3
Reference numeral 01 denotes a drive motor for scanning the image sensor 200, reference numeral 302 denotes a drive belt, reference numeral 303 denotes glass for regulating the position of the document, and reference numeral 304 denotes a document pressing plate for pressing the document against the glass 303.

FIG. 2 is a perspective view of the image sensor 200. The image sensor 200 includes a sensor array 210
, A lens array 220 and the lighting device 1.

The sensor array 210 includes a plurality of linear photoelectric conversion elements 2 corresponding to the length of a document to be read.
11 are accurately arranged in a line on a sensor substrate 212 such as a glass epoxy material.

The lens array 220 includes a plurality of lens elements.

The lighting device 1 has red,
It is composed of an LED that emits light of three colors, green and blue, and a light guide that guides and emits linear light. Here, a type in which the LED which is a light source is installed on only one side of the light guide is shown, but an LED which is installed on both sides of the light guide may be used.

FIGS. 3A and 3B are diagrams for explaining an LED as a light source. FIG. 3A is a perspective view of a portion including the LED, FIG. 3B is a pattern diagram of the LED, and FIG.
(C) shows a circuit diagram of the LED.

21, 22, and 23 are red, green,
Red-LED, Green- emitting three colors of blue light
LED, Blue-LED, 24 is a Zener diode, 25 is an electrostatic guard ring, 26 is a lead, 27 is a white resin, and 28 is a positioning projection. LED 21,
Reference numerals 22 and 23 are attached to the leads 26 in the openings of the white resin 27 with an adhesive, and are electrically connected by wires, and the surfaces thereof are protected by a light transmitting resin.

The Red-LED 21 is a device made of InGaAlP, and the Green-LED 22 and Blue-LED 23 are devices made of a material such as InGaN. Generally, since InGaN is a thin film formed on a sapphire substrate, it is easily damaged by static electricity generated during handling or the like. Therefore, Gr is used as an electrostatic protection element.
A Zener diode 24 is connected in parallel with the een-LED 22 and the Blue-LED 23 on the circuit. The forward voltage of the InGaAlP-based Red-LED 21 is about 2.3 [V], while the GaInN-based Gr-LED 21 has a forward voltage of about 2.3 [V].
The forward voltage of the een-LED 22 and the Blue-LED 23 is as high as about 3.5 [V].

When reading an original, the image sensor 20
While scanning 0 in the sensor sub-scanning direction, the document is illuminated by the illumination device 1 built in the image sensor 200. Then, optical information from the original is transferred to the lens array 220.
Forms an image on the photoelectric conversion element 211 by the
1 converts the signal into an electric signal and transmits the signal to the system to read the entire document.

Here, the control means (not shown) controls the LEDs 21, 22, and 23 as follows when reading a color document and reading a monochrome document.

First, a case of reading a color original will be described with reference to FIG. When reading a color original, Red is applied to one line in the sensor sub-scanning direction.
-LED21, Green-LED22, Blue-L
The ED 23 is independently switched and sequentially turned on and read three times to obtain R, G, and B image information. In order to obtain a desired sensor output, LED 2
The lighting times of 1, 22, and 23 can be independently adjusted within the respective accumulation times.

Next, a case of reading a monochrome original will be described with reference to FIG. When reading a monochrome original, R is set for one line in the main scanning direction of the sensor.
ed-LED21, Green-LED22, Blue
-The LED 23 is turned on at the same time to read only once. At this time, the current consumption value of each of the LEDs 21, 22, and 23 is calculated as the current consumption value (40 [m
A]) (20 [mA]) so as to be within the allowable power value. In addition, LED21, 2
As in the case of sequential lighting, the lighting times of 2, 23 can be independently adjusted within the respective accumulation times.

FIG. 5 shows an example of the setting of the current consumption of each of the LEDs 21, 22, and 23 and the ratio of the amount of light emitted from the LEDs 21, 22, and 23 at that time. In the example shown in FIG. 5, when reading a monochrome document, three readings are performed once and the light amount ratio is × 1.7 compared to reading a color document. It is possible to increase the speed.

The current values 40 of the LEDs 21, 22, and 23 during sequential lighting (when reading a color original) are shown.
[mA], the total current value of the LEDs 21, 22, and 23 at the time of simultaneous lighting (when reading a monochrome original) is 6
Although it is as large as 0 [mA], if it is desired to set the same current value in the system, the total current value during simultaneous lighting (at the time of reading a monochrome original) may be set to 40 [mA].

Even in this case, if the total light amount ratio is set to be equal to or more than × 1, the speed can be increased correspondingly. Here, FIG. 6 shows the relationship between the current value of the LED and the relative light output. As shown by the solid line in FIG.
Green-LED 22 made of InGaN, Blue
-In the LED 23, the lower the current, the better the light conversion rate. Therefore, even if the current values of these LEDs 22 and 23 are reduced, the total light amount ratio can be easily set to x1 or more.

In the case of simultaneous lighting (at the time of reading a monochrome original), not all of the LEDs 21, 22, 23
It is not necessary to reduce the current value of the LED of the present invention in comparison with the current value at the time of sequential lighting (at the time of reading a color original), and the effect of the present invention can be obtained by reducing the current value of at least one LED. it can. In particular, Red-LED 21
Since the forward voltage is small, it can often be used within the allowable power value even if the current value is made the same as the current value during sequential lighting (at the time of reading a color original).

In this embodiment, the light source is LE
D was used, but EL (Electroluminesce)
nce) or the like. Further, the present invention is not limited to the one using the same-magnification optical system, and may use another optical system. For example, as shown in FIG. 7, light from a document illuminated by the
The present invention can be applied to a case where a reduction lens 230 for reducing and projecting on a photoelectric conversion element 211 such as D is used.

In the following, an information processing system comprising an image reading device 70 using the flatbed scanner described in the above embodiment and an information processing device 80 such as a personal computer with reference to FIG. An information processing system configured to transmit image information read by the reading device 70 to the information processing device 80 via a network will be described.

In the image reading device 70, 71 is C
It is a PU and controls the entire image reading device 70.
Reference numeral 72 denotes the flatbed scanner already described. 7
Reference numeral 3 denotes an analog signal processing circuit that performs analog processing such as gain adjustment on an analog image signal output from the flatbed scanner 70.

An A / D converter 74 converts the output of the analog signal processing circuit 73 into a digital signal. Reference numeral 75 denotes a digital image processing circuit,
Shading correction processing is applied to the output data of the D converter 74,
Image processing such as gamma conversion processing and scaling processing is performed.

An interface 77 outputs digital image data subjected to image processing by the digital image processing circuit 75 to the outside. As the interface 77, an interface conforming to a standard adopted by a personal computer such as SCSI or Bi-Centronics is used, and the interface 77 is connected to the information processing device 80 via the interface 77.

The analog signal processing circuit 73, A
/ D converter 74, digital image processing circuit 75, memory 7
6. The interface 77 and the like together constitute a signal processing means according to the present invention.

In the information processing apparatus 80, reference numeral 81 denotes an auxiliary storage device such as a magneto-optical disk or a floppy (registered trademark) disk drive. Reference numeral 82 denotes a display, which displays work on the information processing apparatus 80. A mouse / keyboard 83 is used to input commands and the like to the information processing apparatus 80. Reference numeral 84 denotes an interface for exchanging data, commands, status information of the image reading device 70, and the like with the image reading device 70. 85 is a CPU, 86 is a ROM, 87 is a RAM
It is.

In the information processing apparatus 80 as described above, an image reading instruction can be input to the image reading apparatus 70 by the mouse / keyboard 83. When an image reading instruction is input by the mouse / keyboard 83, the CPU 85 sends a reading command to the image reading device 70 via the interface 84. Then, the information processing device 80 controls the image reading device 70 according to the control program information stored in the ROM 86.

(Other Embodiments of the Present Invention) Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), one device (for example, (A copying machine, a facsimile machine).

Further, the functions of the above-described embodiment are implemented in an apparatus connected to the various devices or a computer in a system so that various devices are operated to realize the functions of the above-described embodiment. The present invention also includes a program which is provided by supplying program code of software for operating the above various devices in accordance with a program stored in a computer (CPU or MPU) of the system or apparatus.

Further, in this case, the program code of the software implements the functions of the above-described embodiment, and the program code itself and means for supplying the program code to the computer, such as the program The recording medium storing the code constitutes the present invention. As a recording medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-RO
M, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) or other operating system in which the program code runs on the computer. Needless to say, the program code is also included in the embodiment of the present invention when the functions of the above-described embodiment are realized in cooperation with the application software or the like.

Further, after the supplied program code is stored in a memory provided in a function expansion board of a computer or a function expansion unit connected to the computer, the function expansion board or the function expansion unit is specified based on the instruction of the program code. It is needless to say that the present invention is also applicable to a case where the CPU or the like provided for performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

It should be noted that the shapes and structures of the respective parts shown in the above-described embodiments are merely examples of the embodiment for carrying out the present invention, and the technical scope of the present invention is thereby reduced. It should not be interpreted restrictively. That is, the present invention can be embodied in various forms without departing from the spirit or main features thereof.

[0045]

As described above, according to the present invention, when a plurality of light sources are turned on simultaneously, the light amount can be increased by increasing the light conversion rate of at least one light source. The accumulation time can be shortened, and the speed of image reading can be further increased. Further, since a plurality of light sources that emit light of different wavelengths are simultaneously turned on, even when reading a color original as monochrome, it is possible to perform good image reading without dropout color.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a flatbed scanner that is an image reading device according to an embodiment of the present invention.

FIG. 2 is a perspective view of the image sensor 200.

FIG. 3 is a diagram illustrating an LED as a light source.

FIG. 4 is a diagram showing lighting timings of LEDs 21, 22, and 23;

FIG. 5 shows setting of current consumption of LEDs 21, 22, and 23;
It is a figure which shows an example with the light amount ratio emitted from LED21,22,23 at that time.

FIG. 6 is a diagram showing a relationship between a current value of an LED and a relative light output.

FIG. 7 is a schematic diagram of an image sensor using a reduction lens 230.

FIG. 8 is a diagram showing an information processing system including an image reading device 70 and an information processing device 80.

FIG. 9 is a schematic view illustrating a conventional image reading apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination device 20 Light source 21 Red-LED 22 Green-LED 23 Blue-LED 24 Zener diode 25 Electrostatic guard ring 26 Lead 27 White resin 28 Positioning convex part 70 Image reading device 71 CPU 72 Flatbed scanner 73 Analog signal processing circuit 74 A / D converter 75 digital image processing circuit 76 memory 77 interface 80 information processing device 81 auxiliary storage device 82 display 83 mouse / keyboard 84 interface 85 CPU 86 ROM 87 RAM 200 image sensor 210 sensor array 211 photoelectric conversion element 212 sensor substrate 220 Lens array 230 Reduction lens 301 Drive motor 302 Drive belt 303 Glass 304 Document holding plate

Claims (8)

[Claims] An illumination unit for irradiating an original; a sensor unit for performing photoelectric conversion; and an optic for imaging light from the original on the sensor unit. Means, when simultaneously lighting a plurality of light sources of the lighting means,
Image reading means for supplying to the plurality of light sources a current value at which the light conversion rate of at least one of the plurality of light sources is higher than the light conversion rate of the other light sources. apparatus. 2. The apparatus according to claim 1, wherein the control unit reduces a current value supplied to at least one of the plurality of light sources when the plurality of light sources are simultaneously turned on. Image reading device. 3. The image reading apparatus according to claim 1, wherein the plurality of light sources of the illuminating means are LEDs that emit light having wavelengths corresponding to red, green, and blue, respectively. 4. An LED that emits light having a wavelength corresponding to red, green, and blue is at least one of InG
The image reading device according to claim 3, wherein the image reading device is made of aN. 5. The image reading apparatus according to claim 1, further comprising signal processing means for processing and transmitting image information obtained by photoelectric conversion by said sensor means. 6. An information processing system comprising: the image reading apparatus according to claim 1; and an information processing apparatus that processes image information obtained by the image reading apparatus. . 7. A procedure for irradiating an original with a plurality of light sources each emitting light of a different wavelength, a procedure for photoelectrically converting light from the original to obtain image information, and a method for simultaneously turning on the plurality of light sources. Supplying a current value at which the light conversion rate of at least one of the plurality of light sources is higher than the light conversion rates of the other light sources to the plurality of light sources. 8. A procedure for irradiating an original with a plurality of light sources each emitting light of a different wavelength, a procedure for photoelectrically converting light from the original to obtain image information, and a method for simultaneously turning on the plurality of light sources. Supplying a current value at which the light conversion rate of at least one light source of the plurality of light sources is higher than the light conversion rate of the other light sources to the plurality of light sources. Characteristic computer-readable storage medium.