JPH04346564A - Method and device for reading image - Google Patents

Abstract

PURPOSE:To reduce the power consumption by securing a constitution where a light emitting part does not substantially emit the light at the parts outside a medium and a shielding cover is not needed when the image of the medium is read. CONSTITUTION:When a reading operation is started, a light emission control means 21 emits the light at each prescribed light emitting part 15 set in the main scanning direction. Based on this light emitting operation, the presence or absence of a medium 13 is detected by a medium detecting means 22. A medium position computing means 23 detects the position of the medium 13 set in the main scanning direction based on the output signal of the means 22. A reed control means 24 emits the light through the part 15 only at a part opposite to the medium 13 and its periphery and also scans the medium 13 in the subscanning direction to read the medium 13.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device and an image reading method for reading images from a medium.

0002

2. Description of the Related Art Today, image reading devices for reading image data on media are used in copying machines, image scanners, and the like. In such image reading devices,
There are types in which the image sensor for reading image data is fixed and the medium side is transported to read the data, and there are types in which the medium side is fixed and the image sensor is moved to read the data.

[0003] Here, an example of an image reading device in which the medium side is fixed and the image sensor side is moved will be described. 2 and 3 are diagrams showing such a conventional image reading device, with FIG. 2 being an explanatory diagram as seen from the top side, and FIG. 3 being an explanatory diagram as seen from the side. The illustrated device includes a housing 1, a glass 2, a medium 3, an integrated contact sensor 4, and a lid 7. The housing 1 forms the outer frame of the image reading device, and a glass 2 is provided on the top surface of the housing 1. The integrated contact sensor 4 includes a plurality of LED (light emitting diode) array light emitting sections 5 and a contact image sensor 6 including a plurality of pixels. The LED array light emitting unit 5 and each pixel of the contact image sensor 6 are provided continuously in the main scanning direction A of the image reading device, and
The D array light emitting section 5 is arranged along both sides of the contact type image sensor 6. Further, the lid 7 is provided above the glass 3 so as to be openable and closable with respect to the housing 1, and has a white back surface.

FIG. 4 shows a circuit diagram of the LED array light emitting section 5. That is, four of each LED array light emitting section 5 are connected in series to form one block, and a plurality of this one block are connected in parallel to a power source. In addition, 8 in the figure is 1
This is a current limiting resistor connected in series to the LED array light emitting section 5 of the block. Also, although omitted in the drawing,
In addition to this, a control circuit is provided that performs reading processing of the medium 3 based on the output signal of the integrated contact sensor 4 and also controls the movement of the integrated contact sensor 4.

Next, the operation will be explained. First, the medium 3 to be read is set on the glass 2 surface with the data reading surface facing downward (glass surface side). Then, the lid 7 is closed so that the reading surface of the medium 3 comes into close contact with the glass 2, and the medium 3 is held down by the lid 7. Next, when a reading start instruction is given from a host device (not shown) or an operation switch provided on the image reading apparatus itself, the image reading apparatus starts reading the medium 3.

In this reading operation, all the LED array light emitting sections 5 on one line in the main scanning direction emit light, and the light reflected from the medium 3 is received by the contact image sensor 6. That is, L
The ED array light emitting unit 5 emits light all at once from one end C to the other end D, and the emitted light passes through the glass 2 surface as shown by the arrow of the integrated contact sensor 4 in FIG.
The reflected light passes through the two glass surfaces again and is taken into the contact image sensor 6. Here, if the medium 3 is smaller than the glass surface 2, the irradiated light from the LED array light emitting unit 5 will protrude outside the medium 3, but this protruding portion will be reflected by the white surface of the lid 7 and will be directed to the contact image sensor 6. It is captured. In this way, the white surface of the lid 7 is also used as a non-data portion of the medium 3. In addition, in such a case, the lid 7
If reading is performed without closing the medium 3, all of the light emitted from the LED array light emitting unit 5 is irradiated outside the medium 3 and does not enter the contact image sensor 6, so the portion outside the medium 3 is considered black. .

After reading one column of data on medium 3,
The integrated contact sensor 4 is moved in the sub-scanning direction B by an amount according to the reading density (generally, an amount determined by dpi (dots/inch)). After that, the leading edge of the medium 3 is read line by line in the main scanning direction in the same manner as described above.
By reading the area from the front end to the trailing edge F, the reading operation for one sheet of medium 3 is completed.

[0008]

However, in the conventional image reading device described above, when reading the medium 3, first the lid 7 is opened, then the medium 3 is set, and then the lid 7 is closed before reading. There was a problem with poor operability due to the processing involved. Here, if the reading process is performed without closing the lid 7, the light emitted from the LED array light emitting unit 5 will directly enter the eyes of the operator in the area outside the medium 3, which will be extremely dazzling, and the operator will not be able to see the medium 3. The worker had to turn his face away from the machine, and in this case too, there was a problem in that the work efficiency was extremely poor. Furthermore, since the irradiation outside the medium 3 is wasted light that does not contribute to reading, there is also the problem that it goes against the demand for power saving in image reading devices.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an image reading device and an image reading method that can improve work efficiency and reduce power consumption to the necessary minimum. With the goal.

0010

[Means for Solving the Problems] An image reading device of the present invention includes a plurality of light emitting sections provided in the main scanning direction, receiving reflected light irradiated onto a medium from the light emitting sections, and reading the medium. In the image reading device, the image reading device includes a light emitting control unit that causes only a predetermined light emitting unit to emit light from the plurality of light emitting units, and a medium that detects the presence or absence of a medium in a main scanning direction based on an output signal of the image sensor. a detection means, a medium position calculation means for detecting a medium position in the main scanning direction based on an output signal of the medium detection means, and a medium position calculated by the medium position calculation means,
The present invention is characterized in that the light emitting section emits light only in a portion directly facing the medium and its vicinity, and further includes a reading control means for scanning the medium in the sub-scanning direction and reading the medium.

[0011]

In the image reading apparatus of the present invention, when a reading operation is started, the light emission control means causes each predetermined light emitting section in the main scanning direction to emit light. When the presence or absence of the medium is detected by the medium detection means based on this light emission, the medium position calculation means detects the medium position in the main scanning direction based on the output signal of the medium detection means. The reading control means causes the light emitting unit to emit light only in a portion directly facing the medium and its vicinity based on the medium detection position, and reads the medium by scanning the medium in the sub-scanning direction. Therefore, when reading an image of the medium, the light emitting section hardly emits light in the area outside the medium, eliminating the need for a shielding lid and saving power.

0012

Embodiments Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an image reading device of the present invention. The illustrated device includes a housing 11, a glass 12, a medium 13, an integrated contact sensor 14, and a control section 20. Housing 11, glass 12, medium 13
The structure of the integrated contact sensor 14 is as follows:
Since the configurations are the same as those of the glass 2, medium 3, and integrated contact sensor 4, detailed description thereof will be omitted here. That is,
The integrated contact sensor 14 includes a plurality of contact image sensors 16 arranged in a line in the main scanning direction, and a plurality of light emitting sections (LED array light emitting sections) provided in a row on both sides of the contact image sensor 16 in the sub scanning direction. ) 15.

The control section 20 is composed of a light emission control means 21, a medium detection means 22, a medium position calculation means 23, and a reading control means 24. The light emission control means 21 is
It is a control means for causing the light emitting sections 15 to emit light in each predetermined light emitting section 15 in the main scanning direction, and is composed of a latch and a shift register circuit, etc., which will be described later. The medium detection means 22 detects the medium 13 in the main scanning direction based on the output signal of the image sensor 16.
This is a means for detecting the presence or absence of a signal, and is composed of an adder, etc., which will be described later. When the medium 13 is detected by the medium detection means 22, the medium position calculation means 23 controls the light emission of the light emitting section 15 so that it emits all light near the detection section of the medium 13, and controls the light emission based on the output signal of the image sensor 16 due to this light emission. , a means for detecting the position of the medium 13 in the main scanning direction, and is composed of a processor and the like. The reading control means 24 is means for scanning the medium 13 in the sub-scanning direction and reading the medium 13 based on the medium position calculated by the medium position calculation means 23, and is composed of a processor, a pulse motor, etc. .

FIG. 5 shows a specific configuration of the light emission control means 21. That is, the light emission control means 21 includes a latch and shift register circuit 25 that respectively control the light emission of each light emitting section (light emitting element) 15. Further, numeral 26 in the figure indicates a current limiting resistor connected in series with each light emitting section 15. The latch and shift register circuit 25 includes a serial data signal input terminal SIN for lighting the light emitting section, a clock signal input terminal CK for data shifting, an output enable signal input terminal OE, and a data latch signal input terminal LH.

FIG. 6 shows a concrete block diagram of the reading section in the embodiment apparatus. The device shown in the figure includes a central processing unit (CPU) 27 and a read-only memory (ROM).
28, a random access memory (RAM) 29, a synchronization signal generation section 30, a line counter circuit 31,
A medium detection register 32, an adder 33, an image sensor counter circuit 34, a pulse motor control section 35,
It consists of a pulse motor 36, a contact type image sensor 16, a line buffer 37 for read data, and an upper interface section 38.

The central processing unit 27 includes the medium position calculation means 2
3 and the read control means 24, and also controls the pulse motor control section 35 and the like via the bus 39. The read-only memory 28 is a memory that stores reading programs and the like, and the random access memory 29 is a memory that stores read data and the like. The synchronization signal generation section 30 is a circuit that generates a synchronization signal for synchronizing the drive amount of the integrated contact sensor 14 and the scanning of the medium 13 under the control of the pulse motor control section 35 . The line counter circuit 31 is a circuit that counts which line the contact image sensor 16 scans in the sub-scanning direction.

The medium detection register 32 and the adder 33 are circuits that constitute a feature of the present invention. It is configured to set information indicating that a medium is present in the medium detection register 32 when one or more bits of white data (medium present data) are present. The image sensor counter circuit 34 is a circuit that counts the contact type image sensor 16 in the main scanning direction, that is, it specifies which pixel among a plurality of pixels the output of the contact type image sensor 16 is output from. be. Further, the pulse motor control unit 35 is a circuit that controls the pulse motor 36 to drive the contact image sensor 16 in the sub-scanning direction, and the read data line buffer 37 is a circuit that controls the pulse motor 36 to drive the contact image sensor 16 in the sub-scanning direction. The upper interface section 38, which is a buffer circuit for holding image data, is an interface circuit to a higher-level device such as a microcomputer.

Next, the operation will be explained. First, Figure 5
The operation of the light emission control means 21 shown in FIG. First, the serial data signal for lighting the light emitting section is converted into one bit by the clock signal for data shifting input from the serial data signal input terminal SIN for lighting the light emitting section of the latch and shift register circuit 25 to the clock signal input terminal CK for data shifting. Input one by one. When the light emission data for one column is completed, the data is stored in the register by a latch signal input from the data latch signal input terminal LH. Next, when the output enable signal is input to the output enable signal input terminal OE, the light emission data stored in the register is notified to each light emitting section 15, and only the light emitting section 15 at the specified position emits light. . By repeating this operation row by row, a predetermined light emitting section 1 is set in the main scanning direction.
Only 5 can be controlled to emit light.

FIG. 7 is an explanatory diagram of the reading operation of the apparatus of the present invention. In order to read the medium 13 as shown in this figure, it is necessary for the integrated contact sensor 14 to move from the movement position G to the position H. Here, first, reading starts from medium 13.
Suppose that it starts before the tip G of . Initially, only each point (number of N-1 points) obtained by dividing one line in the main scanning direction into N is made to emit light. Further, as for the value of N, the brightness and light amount of the light emitting unit 15 are evaluated, and the maximum number is set so that the brightness does not bother the user during operation. In this way, the light emitting section 15 emits light at each point, but the integrated contact sensor 14
Since the medium 13 does not exist at the light emitting point until reaching the point, the light from the light emitting section 15 does not enter the image sensor 16 as reflected light, and the entire row in the main scanning direction is black data (medium not detected).

When the integrated contact sensor 14 reaches the H point, the 1/N division point that overlaps the medium 13 portion changes to white data (medium detection). As a result, the adder 33
sets a medium presence signal in the medium detection register 32 when there is one or more bits of white data in one column of image data. By setting the medium detection register 32, the central processing unit 27 starts reading data from the medium 13. Further, when reading the next line in the main scanning direction, the light emitting sections 15 up to the 1/N dividing point on both sides of the H point in the main scanning direction are controlled so as to emit all light. As a result, a portion where several dots or more of black data are consecutive is determined to be a portion outside the medium 13, and the light emitting portion 15 to be emitted in the next line is determined. In this way, by detecting the position of the medium 13 in the main scanning direction and controlling the light emission of the next line, and by performing this up to the I point, the light emitting section 12 is placed only within the approximate outline of the medium 13.
5 light emission can be performed. Since black data continues after point I, it is determined that reading of the medium 13 has been completed, and the light emitting section 15 does not emit light thereafter.

FIG. 8 is an enlarged view of section J in FIG. 7. In this figure, thick solid lines 39 indicate light emitting parts 15
The thin solid line 40 indicates the trajectory of light emitted at each predetermined point.
is the reading line in the main scanning direction, and the dotted line 41 is the medium 13
The light emitting section 15 is shown fully emitting light below the figure. In this way, until the medium 13 is detected, the light emitting section 15 emits light at each predetermined point, and after the detection, almost only the portion of the medium 13 emits light completely. Therefore, data can be read from the medium 13 without causing the light emitting section 15 to emit much light in the area outside the medium 13.

In the above embodiment, an example was shown in which the medium 13 side is fixed and the sensor side is moved; however, the present invention is not limited to this, and the structure may be such that the medium 13 side is conveyed and read by the sensor. Also, the same effect as the above embodiment is achieved.

[0023]

[Effects of the Invention] As explained above, according to the image reading device and the image reading method of the present invention, the light emitting section is configured to hardly emit light in areas other than the reading medium when reading an image, which was previously necessary. There is no need for a lid to block the irradiation light from the light emitting part, eliminating the need to open and close the lid and also preventing the operator from being dazzled, resulting in a significant improvement in work efficiency. Furthermore, since unnecessary light emission is eliminated, power consumption can be reduced to the necessary minimum. Moreover, by holding the medium by hand, the reading surface does not have to be particularly horizontal; for example, the image reading surface can be vertical (the image reading device is installed vertically). As the scope of use expands, it can be expected to be used in a variety of applications.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an image reading device of the present invention.

FIG. 2 is a configuration diagram of a conventional image reading device viewed from the top side.

FIG. 3 is a side configuration diagram of a conventional image reading device.

FIG. 4 is a circuit diagram of a light emitting unit of a conventional image reading device.

FIG. 5 is a specific configuration diagram of the light emission control means of the image reading device of the present invention.

FIG. 6 is a specific configuration diagram of the image reading device of the present invention.

FIG. 7 is an explanatory diagram of the reading operation of the image reading device of the present invention.

8 is an enlarged explanatory diagram of the J portion in FIG. 7. FIG.

[Explanation of symbols]

13 Medium 15 Light emitting part 16 Close-contact image sensor 21 Light emission control means 22 Medium detection means 23 Medium position calculation means 24 Read control means

Claims (2)

[Claims] 1. A plurality of light emitting units provided in the main scanning direction; receiving reflected light irradiated onto a medium from the light emitting units;
The image reading device includes an image sensor that reads the medium, and a light emission control means that causes only a predetermined light emitting section to emit light from the plurality of light emitting sections, and an output signal of the image sensor to read the medium in the main scanning direction. a medium detection means for detecting the presence or absence of the medium; a medium position calculation means for detecting the medium position in the main scanning direction based on the output signal of the medium detection means; and a medium position calculation means for detecting the medium position in the main scanning direction based on the medium position calculation means An image reading device comprising: a reading control means that causes a portion of the portion directly facing the medium and its vicinity to emit light, scans the medium in a sub-scanning direction, and reads the medium. 2. A plurality of light emitting units provided in the main scanning direction; receiving reflected light irradiated onto a medium from the light emitting units;
An image reading method comprising: an image sensor that reads the medium; the plurality of light emitting units emit light only in a portion directly facing the medium and its vicinity; the medium is scanned in a sub-scanning direction; An image reading method characterized by reading a medium.