JP3278340B2 - Image reading device and image recording device - Google Patents

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 for reading an original image and an image recording apparatus for recording an image on a recording sheet.

[0002]

2. Description of the Related Art Conventionally, a printer that records an image on recording paper by a recording head by mounting a recording head such as an ink jet head or a thermal head on a carriage and moving the carriage has been used as an output device such as a personal computer or a word processor. It is used as

In such a printer, an image reading unit having a photoelectric conversion function is mounted on a carriage in place of a recording head, a document image is read, and image data obtained by reading is input to a personal computer, a word processor, or the like. Proposals have been made to use it as a scanner.

[0004]

In order for such a printer to function sufficiently as a scanner, it is necessary not only to read the original image as a binary image of black and white, but also as a multi-valued image including black and white and halftone density. Reading is demanded with the improvement of the processing capability of personal computers and the like.

[0005] However, in reading a multi-valued image, image processing of several times the amount of data is required for reading a binary image, and therefore both a binary image reading and a multi-valued image reading are possible. For this purpose, the apparatus must be configured in accordance with a multi-valued image reading operation with a large data amount, which causes, for example, an increase in memory capacity and an increase in processing time. When a device configured to read a multi-valued image is frequently used for reading a binary image, the configuration for reading a multi-valued image is useless and is not very preferable.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to enable not only binary reading but also multi-level reading of an original image with a simple configuration. Indicates the image data representing the original image
A line sensor for reading a document image; a first conversion unit for converting image data from the line sensor into multi-valued image data;
A second converting means for converting the image data from the line sensor into a binary image data, before according to the instruction of the multi-level read mode
The multi-value image data from the first conversion means is output to an external device.
The second conversion means in response to an instruction in the binary reading mode.
Output means for outputting the binary image data to an external device , for reading the original image when outputting the multi-valued image data .
Wherein the number of pixels the line sensor, and smaller than the picture <br/> prime of the line sensor used in the output of the binary image data to the reading of the original image are, and, a pixel located at the center of the line sensor The present invention provides an image reading apparatus to be used , and further includes a recording paper based on recording data from an external device.
In an image recording apparatus for recording an image on a recording paper ,
Conveying means for conveying in a direction, the conveyance of the said conveying means
A carriage which the recording head for image recording on recording paper is mounted, a second said carriage relative to the recording sheet
And a line sensor for reading an image instead of the recording head on the carriage.
The reading unit and can be mounted was example, a configuration for reading a document image by moving by the moving means the carriage in which the reading unit is mounted to the document conveyed by said conveying means, further, the multi-level Reading
Output multi-valued image data to external equipment
And removes the binary image data according to the instruction of the binary reading mode.
Output to external devices, and when outputting multi-valued image data
The number of pixels of the line sensor used for reading an image is 2
Used for reading the original image when outputting the value image data.
The number of pixels of the line sensor
An object of the present invention is to provide an image recording apparatus using a pixel located at the center of the in-sensor .

[0007]

FIG. 1 is a diagram showing the configuration of an image recording / reading apparatus to which the present invention is applied. Reference numeral 101 denotes an ink jet head (recording head) having 128 ink ejection ports.
It is configured to be removable. 104 and 105 are guide shafts which hold the carriage 103 so as to be movable in the axial direction, and 106 is a belt. The carriage motor 107 is used to reciprocate the carriage 103 in the direction of arrow b along the guide shafts 104 and 105. The driving force is transmitted to the carriage 103. Reference numeral 108 denotes a flexible printed card (FPC), which electrically connects the print head 101 and the control board 109. A paper feed roller 110 is rotated by the roller motor 102 and moves the recording paper 111 in the direction of arrow a.

The operation of recording an image will be described below. As described above, the print head 101 has 128 ink ejection ports. When the carriage 103 moves once (forward) from left to right in the figure, a maximum of 12
Eight lines of dot recording are performed. After one forward movement of the carriage 103 from left to right in the figure, the paper feed roller 110
Rotates to move the recording paper 111 by the recording width. Further, the carriage 103 is moved (returned) from right to left in the figure to prepare for the next image recording. The necessary recording on the recording paper 111 is performed by repeating the movement of the carriage 103 and the recording paper 111 a plurality of times.

In the above description, the operation of dot recording during the forward movement of the carriage 103 has been described, but reciprocal printing for dot recording may be performed not only at the time of forward movement but also at the time of backward movement.

As described above, the recording head 101 can be attached to and detached from the carriage 103, and in the present embodiment, a scanner unit 102 shown in FIG. The scanner unit 102 photoelectrically converts an image of a document conveyed by the paper feed roller 110 instead of the recording paper 111 and outputs the image as an electric signal.

In FIG. 2, reference numeral 201 denotes an LED for exposing a document to be read; 202, a field lens;
03 is a mirror, 204 is a master lens, LED2
The reflected light from the original document exposed by 01 is guided to the line sensor 205. The line sensor 205 has 128 pixels of photoelectric conversion elements arranged on one line, and outputs an analog image signal of a level corresponding to the density of a document image.

A reading operation in which the scanner unit 102 is mounted on the carriage 103 instead of the recording head 101 to read a document image will be described below.

The document is conveyed to a predetermined reading position by a paper feed roller 110 instead of the recording paper 111. The carriage 103 on which the scanner unit 102 is mounted moves forward from the left to the right in the drawing, similarly to the above-described recording operation. As a result, the image on the original is converted to a line sensor 205 with a width of 128 pixels.
Is read. After one forward movement of the carriage 103, the paper feed roller 110 rotates to move the document by 128 pixels, and moves the carriage 103 from right to left to prepare for the next image reading. Then, the image of the document is read by repeating the movement of the carriage 103 and the document a plurality of times.

In the above description, the original image is read during the forward movement. However, the image may be read not only during the forward movement but also during the backward movement.

The amount of movement of the original due to the rotation of the paper feed roller 110 by the roller motor 102 is equal to
Not only 8 pixels, but also, for example, 1/2 64 pixels or 1 pixel
A movement of 32 pixels of / 4 is possible.

As will be described later in detail, the scanner unit 102 has a binary reading mode in which an image is read as binary information of black and white, and an image having three or more values including an intermediate density, for example, 64 bits of 8-bit gradation. A reading operation is performed in a multi-value reading mode for reading as multi-value information.

FIG. 3 is a block diagram showing the entire apparatus of FIG. The recording head 101 or the scanner unit 101 is connected to the head connection unit 2 according to the purpose of use.

First, the operation when the present apparatus is used as a recording apparatus will be described together with the function and structure of each block. In this case, the recording head 101 is connected to the head connection unit 2.
Is connected.

Recording data for recording (or printing, hereinafter referred to as recording) such as characters or images is transmitted from the host computer 11 through an interface (I / F) 10 while being controlled by the host computer 11 and the arithmetic and control unit 8. The transfer is performed. The controller 5 receives the recording data, processes the recording data into dot data for dot recording on recording paper by the recording head 101, and stores the processed dot data in the memory 25. Further, the controller 5 reads the dot data from the memory 25 under the control of the arithmetic and control unit 8 and reads out the head connection line 3 (FPC 108 in FIG. 1),
The recording data is transferred to the recording head 10 through the head connection unit 2.
1 and characters or images are dot-recorded on the recording paper.

The roller motor 14 (corresponding to the roller motor 102 in FIG. 1) is rotated by the arithmetic control unit 8 and the motor driver 6 controlled by the controller 5 to feed recording paper.

The carriage 13 (corresponding to the carriage 103 in FIG. 1) is moved by driving the carriage motor 12 by the motor driver 7 controlled by the arithmetic control unit 8 and the controller 5.

Further, the recording paper or
It is detected whether an original for reading an image is set on a paper table (not shown), and whether the carriage 13 is at a start position.

The interface 10 receives not only the above-described characters and image data but also various parameters relating to image recording and reading from the host computer 11.
Various operation controls for image recording and reading are executed.

Next, the operation when this apparatus is used as an image reading apparatus will be described. In this case, the scanner unit 102 is connected to the head connection unit 2.

As described above, when operating as an image reading apparatus, the scanner unit 102 scans a document in the same manner as the movement of the recording head 1 during recording. LED 17 in scanner unit 102
(Corresponding to LED 201 in FIG. 2) irradiates the original,
A line sensor 18 having photoelectric conversion characteristics (corresponding to the line sensor 205 in FIG. 2) detects reflected light such as characters or images. The signal detected by the line sensor 18 is amplified by an amplifier 19 to an optimum level at a level handled by an analog / digital converter (hereinafter referred to as A / D) 20,
Input to D20. Here, the data converted into digital data is subjected to correction or image processing such as shading correction and binarization by the image processing IC 21 and transferred to the main unit as image data.

This transfer is performed by the host computer 11 via a path reverse to the flow of the recording data at the time of recording described above.
Will be sent to That is, the image data is stored in the memory 25 from the image processing IC 21 via the head connection unit 2, the head connection line 3, and the controller 5. Controller 5
Is a host computer 11 through an interface 10
The image data is sent while synchronizing with. At this time, the controller 5 transfers the image data received from the image processing IC 21 under the control of the arithmetic control unit 8 in a form that is easy to send through the interface 10 or a form that is easy for the host computer 11 to handle. .

Next, the switching operation of the number of read pixels when reading an image will be described. As described above, the present embodiment can operate in the binary reading mode and the multi-value reading mode. This reading mode is set in the host computer 1
1, the arithmetic control unit 8 controls the operation of the apparatus according to the mode.

For example, if the number of pixels of the line sensor 18 is 12
Assuming that there are eight, if the image reading is in the binary reading mode, the image reading operation is performed using the entire line sensor 18 as shown in FIG. FIG. 5 shows a read range RA when one line is scanned by using all 128 pixels of the line sensor 18. The amount of data at this time is 210 mm for one line (A4 size horizontal), and the resolution is 3
Assuming 60 dpi, 1 (bit) × 128 (pixel) × 360 / 25.4 × 210 (mm) = 380976.4 (bit) Expression (1) (FIG. 4), and a memory capacity of about 381 Kbits or more is obtained. Required. That is, it is sufficient that the memory 25 has a capacity of 1 Mbit.

Since the memory 25 is used when the main unit operates as a recording device, it is used.
This is the minimum required capacity used for other arithmetic control.

Next, the operation of the 8-bit multi-value read mode will be described. In the 8-bit multi-level reading mode, the data amount when reading is performed using all the pixels of the line sensor 18 can be calculated by multiplying the above equation (1) by 8 bits. That is, 8 × 380976.
4 = 3.05 Mbits is required, and the memory capacity must be greatly increased, resulting in an undesired configuration such as an increase in cost.

Therefore, in this embodiment, in the 8-bit multi-value read mode, as shown in FIG. 4 (2) or (3),
The number of pixels to be read is reduced to 64 or １ ／ of 32 for the total 128 pixels of the line sensor 18, thereby reducing the data amount per scan and using the memory 25 as it is. To read multi-valued images.

That is, for example, as shown in FIG. 4C, one of the parts of the line sensor 18 (any part may be used).
If / 4 is used, the memory capacity is 3.05M / 4 =
It suffices to have 762.5K bits. Therefore, by using the memory 25 having a memory capacity of 1 Mbit, a multi-valued image reading apparatus can be configured without increasing the cost.

Next, the configuration of the image processing IC 21 relating to the above-described binary and multi-value reading modes will be described with reference to FIG.

According to the instruction from the host computer 11, 2
In the case of operating in the value reading mode, an analog signal of an image obtained by reading all 128 pixels of the line sensor 18 is amplified by the amplifier 19 and converted into digital data by the A / D 20. At this time, the binary / multi-value selection circuit 32 selects the binary comparator 30 in the image processing IC 21 according to the instruction of the binary reading mode, and uses this binary comparator to convert the digital data into a predetermined threshold. Determined as white / black (binary) by value and 12
All eight pixels are output (FIG. 7 (1)).

On the other hand, in the case of operating in the multi-value reading mode, analog signals of the image obtained by reading with all 128 pixels of the line sensor 18 are amplified by the amplifier 19 and the A / A At D20, the data is converted into digital data (multi-value data). At this time, in accordance with the instruction of the multi-value reading mode, the binary / multi-value selection circuit 32 selects data for one-fourth of the total pixels of the line sensor 18 by the multi-value data selection circuit 31 in the image processing IC 21. Remaining 3
Discard / 4 data without using it. That is, FIG.
The data for 128/4 = 32 pixels shown in (3) is processed by the image processing IC 21 and output as multi-valued data ((2) in FIG. 7). Also, this 32 pixel range may use any part of the 128 pixels,
Needless to say.

In the scanning operation of the scanner unit in the multi-value reading mode, since the reading width per scan is 1/4 of that in the binary reading mode, the moving width of the original is also 1/4. The number of scans in the multi-value reading mode is 4 times larger than that in the binary reading mode.
The scanning operation is doubled.

With the above arrangement, binary reading of an image is performed.
Multi-value reading can be realized without greatly changing the configuration of the main unit as a recording device and without increasing the cost.

However, by using a specific part of the line sensor 18, the mechanical optical performance and accuracy of the apparatus can be maximized.

As shown in FIG. 8 (2), when a substantially uniform white original is read by the line sensor 18, the line sensor 18 receives reflected light having a mountain-like distribution from the original, thereby obtaining a line. The output of the sensor 18 also has an electric signal waveform having a peak distribution.

This is due to the influence of the optical characteristics of the LED 201, which is the light source of the optical system in FIG. 2, and the lens 202, mirror 203, and lens 204 for guiding the reflected light to the line sensor 18.

For example, as a characteristic of the lens 204, it is generally known that the intensity of light passing through the center of the lens is different from the intensity of light passing outside the lens (cosine cosine). 8 (2), the high level of the waveform in FIG. 8 (2) is the center of the lens 205 and the sensor 18, and the low level of the waveform is the outer part (both ends) of the lens 205 and the line sensor 18.

Accordingly, in the signal waveform shown in FIG. 8B, even if a substantially uniform amount of light is emitted from the document as reflected light, the outer portion (both ends) of the signal waveform is compared with the central portion. , The amount of reflected light received by the sensor 18 is small. This is an image reading device
This indicates that the resolution and gradation, which are the standards for performance and accuracy, are inferior in the outer portion (both ends) of the line sensor 18 than in the central portion.

From the above, 64 pixels located at the center of the lens 205 and the line sensor 18 or 32 pixels
Using pixels (FIG. 8 (1)) as effective pixels
This is a method of use in which the performance and accuracy are enhanced mechanically and optically.

FIG. 8B shows the center C of the line sensor 18.
An example is shown in which 32 pixels (all 64 pixels) on each of the left and right sides of P are used as effective pixels.

It has been described that the use of the central portion of the line sensor 18 provides higher performance and higher accuracy in consideration of the characteristics generated from the lens 205 and the like.
An example in which the use of the central portion of the sensor 18 achieves high performance and high accuracy by the configuration method according to D201 will be described below.

As described above, since the light source of the scanner unit 102 is the LED 201, the light source is constituted by almost points. According to this, as shown in FIG. 9, a portion where the distance from the LED 201 to the document is short and a portion where the distance is long, and the intensity of irradiation light has a strong and weak distribution. From this, the reflected light received by the line sensor 18 from the document can also have a peak-like intensity depending on the distance from the LED 201 to the document as described above, and the output waveform of the line sensor 18 is as shown in FIG. Similarly, it has a mountain-like waveform.

Here, it is needless to say that a high-level portion at the center of the peak waveform becomes a portion with a large amount of light, has a good S / N, and naturally has good gradation and the like.

Therefore, as in the previous embodiment, the line sensor 1
By using 64 central pixels or 32 pixels of 8 128 pixels as effective pixels, it is possible to configure a higher-performance and higher-precision image reading apparatus.

In the above description, 128 of the line sensor 18
The example in which 64 pixels are used as effective pixels among the pixels has been described. However, when 32 pixels are used as effective pixels, 16 pixels on the left and right of the center CP of the line sensor 18 (a total of 32 pixels) may be used.

The numbers of the left and right pixels based on the center CP do not necessarily have to be equal, but are appropriately selected according to the characteristics of each device.

In the above embodiment, a line sensor having 128 pixels is used. However, the number of pixels of the line sensor is not limited to this. Needless to say, it may be executed.

The present invention can be applied not only to a device for both image recording and image reading, but also to a device exclusively for image reading.

(Other Embodiments) In the embodiments described above,
The reading resolution by the scanner unit 102 is the same in the binary reading mode and the multi-value reading mode, but in the multi-value reading mode, the resolution is, for example, １ ／.
Then, 1/2 of all the pixels 128 of the line sensor 18 is used as the image reading width ((2) in FIG. 4). Thus, it is possible to adopt a configuration in which the entire data amount is set to the same data amount (と in the binary reading mode) as in the previous embodiment, and a multi-value reading operation is performed.

In the first embodiment, 3/4 data not used after the output of the A / D 20 is discarded.
1/4 available for line sensor 18, 3 remaining
It is also possible to make a configuration in which / 4 is disabled and a signal is output from the line sensor 18 and input to the amplifier 19 and further to the A / D 20.

[0055]

As described above, according to the present invention,
There is an effect that not only binary reading of an image but also multi-value reading can be realized with a simple configuration and excellently without significant cost increase.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image recording apparatus to which the present invention is applied.

FIG. 2 is an overall block diagram of the apparatus.

FIG. 3 is a structural diagram of a main part of a mechanical unit.

FIG. 4 is an explanatory diagram of the number of sensor pixels.

FIG. 5 is an explanatory diagram of a reading range.

FIG. 6 is an explanatory diagram of binary / multi-value selection.

FIG. 7 is an explanatory diagram of a reading range in a signal.

FIG. 8 is an explanatory diagram of a reading range.

FIG. 9 is an explanatory diagram of characteristics of irradiation light amount.

[Explanation of symbols]

 2 Head Connection 3 Head Connection 18 Line Sensor 101 Recording Head 102 Scanner Unit

Claims (10)

(57) [Claims] An image data representing a document image is sent to an external device.
A line sensor for reading a document image, a first conversion unit for converting image data from the line sensor into multi-valued image data, and binary image data from the line sensor. A second conversion means for converting the data into a multi-value reading mode,
Outputs multi-valued image data to external equipment, binary reading mode
The binary image data from the second conversion means in response to the instruction of
Output means for outputting to an external device, and before using for reading a document image when outputting multi-valued image data
The number of pixels serial line sensor, when the output of the binary image data
An image reading apparatus, wherein the number of pixels of the line sensor used for reading a document image is smaller than that of the line sensor , and a pixel located at the center of the line sensor is used . 2. The output means should output to an external device.
The image reading apparatus according to claim 1, characterized in that it comprises a storage means for storing the multivalued image data and the binary image data can. 3. A line sensor for outputting multi-value image data.
All pixels are used for reading the original image and the binary image data
At the output of the data, some pixels of the line sensor
The image reading apparatus according to claim 1, characterized by using the reading of the image. 4. The apparatus according to claim 1, wherein said line sensor is moved in a first direction.
First moving means, and second movement for moving the document in a second direction
2. The image according to claim 1, further comprising:
Reader. 5. The method according to claim 1, wherein the second step is performed when outputting multi-valued image data.
The amount of movement of the original by the moving means is output as binary image data.
The amount of movement of the original by the second moving means during
5. The image reading method according to claim 4, wherein
Taking device. 6. Recording based on recording data from an external device.
In an image recording apparatus for recording an image on a recording sheet, a conveying means for conveying the recording paper in a first direction , and an image recording apparatus for recording an image on the recording paper conveyed by the conveying means .
A carriage on which a recording head is mounted, and moving the carriage in a second direction with respect to the recording paper.
Moving means, the carriage and the recording head
Scanning unit with line sensor for reading an image instead
Can be attached to the original conveyed by the conveying means.
The carriage on which the reading unit is mounted is
Reading of the original image by moving by the moving means
And a multi-level reading mode instruction.
Output multi-valued image data to an external device, and
Output binary image data to an external device in accordance with the instruction of the
In addition, it is used for reading a document image when outputting multi-valued image data.
The number of pixels of the line sensor
Image of the line sensor used for reading the original image
Smaller than the prime number and the center of the line sensor
Characterized by using a pixel located at
Image recording device. 7. Multi-valued image data to be output to an external device and
And storage means for storing binary image data.
The image recording apparatus according to claim 6, wherein 8. The recording head is mounted on the carriage.
When the image is recorded on the recording paper,
Claims characterized by storing record data from equipment
Item 8. The image recording device according to Item 7. 9. When outputting multi-valued image data, a line sensor is used.
All pixels of the image are used for reading the original image,
When outputting data, some pixels of the line sensor
7. The image forming apparatus according to claim 6, which is used for reading an image.
Image recording device. 10. The method according to claim 1, wherein the multi-valued image data is outputted.
The amount of document transported by the transport means when outputting binary image data
Smaller than the document transport amount by the first transport unit in
The image recording apparatus according to claim 6, wherein: