JPH0670098A - Picture reader - Google Patents

Abstract

PURPOSE:To improve the reproducibility and outward appearance of original pictures. CONSTITUTION:By main scanning signals R of first and second times outputted from a main scanning signal generation part 7, light receiving signals are synchronously outputted from image sensors 3 and 4 to a memory control part 5. The memory control part 5 successively reads the light receiving signals from the image sensors 3 and 4, converts them to digital. data (picture data) and stores them in the block memories 631, 641, 632 and 642 of a memory 6. Then, the memory control part 5 first reads the picture signals of the block memory 641, synchronously reads the picture signals of the block memory 631 and the picture signals of the block memory 642 and then, reads the picture signals of the block memory 632.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a plurality of image sensors arranged in the width direction of a document, and each image sensor sequentially scans the document from the same end side in the width direction to read the document, and the outside of an image forming apparatus or the like. The present invention relates to an image reading device that outputs read data to a device.

[0002]

2. Description of the Related Art Conventionally, in an image reading apparatus used in an image forming apparatus such as a facsimile, an image sensor composed of a photoelectric conversion element array in which photoelectric conversion elements such as photodiodes are arranged in a line is arranged in the width direction of an original. The document image is set in the width direction (hereinafter referred to as main scanning), and the image sensor or the document is moved to relatively scan in the length direction of the document (hereinafter referred to as sub scanning). I am trying to read. In addition, since the number of photoelectric conversion elements that can be mounted on a single image sensor is limited, if the document width is large, the number of pixels and length will be insufficient. Are arranged side by side, and these image sensors are simultaneously scanned in the same direction to read a document.

As described above, since the photoelectric conversion element array is sequentially scanned to read the original, each image sensor has a time difference between the timing on the reading start end side and the timing on the other end side. On the other hand, as described above, the image sensor and the document are relatively moved in the length direction of the document during this period. Therefore, a discontinuity of one line of the photoelectric conversion element array occurs at the boundary between the image sensors arranged in parallel. For example, as shown in FIG. 10, when the straight line S on the original G is read by the image sensors 1 to 4, discontinuity occurs in the output data of the straight line S due to the difference in the read timing generated at the boundary between the image sensors 1 to 4. When an image is formed from this output data, the original image is not accurately reproduced as shown in the lower part of FIG. 10, and the appearance is deteriorated.

As a countermeasure against this, the adjacent image sensors are arranged so that the main scanning directions thereof are alternately opposite to each other, the reading timings at the boundaries of the respective image sensors are made coincident with each other, and the output data of the image reading device is A device that eliminates the above discontinuity has been proposed (JP-A-2-202265).

[0005]

However, in the image reading apparatus described in Japanese Patent Laid-Open No. 2-202265, the main scanning directions of the adjacent image sensors are alternately opposite to each other. The wirings connected to one end become alternately opposite positions and become complicated. Further, when the reading loci of the respective image sensors are connected, the image is bent and the reproducibility and appearance of the image are deteriorated. Further, in order to eliminate this bending, it is disclosed that each image sensor is arranged so as to be inclined by an amount corresponding to the inclination of the reading locus of each image sensor. However, it is necessary to adjust the tilt of each image sensor, which is troublesome. Further, since the tilt adjustment is extremely small, it requires skill to perform the adjustment work.

An object of the present invention is to solve the above problems and to provide an image reading apparatus which is excellent in reproducibility and appearance of a document image.

[0007]

In order to achieve the above object, the present invention is an image reading apparatus for reading a document image by moving the document in the lengthwise direction of the document and receiving reflected light from the document. A first row arranged in the width direction having photoelectric conversion elements No. 1 to n arranged in one row in order from the front side in the width direction of the document, which generate an image signal according to the intensity. An image sensor and a second image sensor, a scanning means for scanning the photoelectric conversion element arrays of each image sensor in a direction from No. 1 to n at a predetermined speed in synchronization with each other, and first, second, third, fourth A storage unit having a memory block; an operation of writing an image signal captured by the first and second image sensors into the first and second memory blocks according to the scanning direction; and the first and second images. Writing means for alternately performing the operation of writing the image signal taken in by the sensor into the third and fourth memory blocks in accordance with the scanning direction, and the third memory block and the second memory block. And a reading unit for alternately performing an operation of reading the stored image signals in the written order and an operation of reading the image signals stored in the first memory block and the fourth memory block in the written order. The first and second image sensors are arranged such that the first photoelectric conversion element of the second image sensor is located next to the nth photoelectric conversion element of the first image sensor (claim 1).

The reading means continuously reads the image signals stored in the third memory block and the second memory block in the order in which they are written, and stores them in the first memory block and the fourth memory block. The image signals are continuously read in the order in which they are written (claim 2).

The reading means synchronously reads the image signals stored in the third memory block and the second memory block in the order in which they are written, and stores them in the first memory block and the fourth memory block. The image signals are read out in synchronism with the written order (Claim 3).

[0010]

According to the first aspect of the invention, the image signals captured by the first and second image sensors in the i-th scanning are stored in the first and second memory blocks, respectively, and i +
The image signals captured by the first and second image sensors in the first scan are stored in the third and fourth memory blocks, and the image signals captured by the first and second image sensors in the i + 2th scan are stored. It is stored in the first and second memory blocks. Since the scanning time of this image signal differs between the n-th photoelectric conversion element of the first image sensor and the first photoelectric conversion element of the second image sensor, the scanning time differs by the time during which the scanning of the photoelectric conversion element array makes one round. , There is a discontinuity. Therefore, when the i-th scanning is completed, the image signals stored in the third memory block and the second memory block are read out, and when the i + 1-th scanning is completed, they are stored in the first memory block and the fourth memory block. The image signal stored in the third memory block and the image signal stored in the second memory block are read out when the i + 2nd scan is completed. In this case, the data stored in the third memory block at the end of the i-th scanning is the image data obtained by the first image sensor in the (i-1) th scanning, and is also stored in the second memory block. The generated data is image data obtained by the second image sensor in the i-th scanning. Similarly, at the end of the (i + 1) th scanning,
Image data obtained at the i-th time of the first image sensor is stored in the first memory block, and image data obtained at the i + 1-th time of the second image sensor is stored in the fourth memory block.
At the end of the second scanning, the image data obtained at the (i + 1) th time of the first image sensor is stored in the third memory block, and the image data obtained at the (i + 2) th time of the second image sensor is stored in the second memory block. . The discontinuity is eliminated by reading these in the order described above.

According to the invention described in claim 2, the third aspect
The image signals stored in the memory block and the second memory block are continuously read out serially. Also, the first
The image signals stored in the memory block and the fourth memory block are continuously read out serially.

According to the invention of claim 3, the third aspect
The image signals stored in the memory block and the second memory block are synchronously read in parallel. Further, the image signals stored in the first memory block and the fourth memory block are synchronously read in parallel.

[0013]

First, a schematic structure of an image forming apparatus to which the image reading apparatus of the present invention is applied will be described with reference to FIG.

The image forming apparatus 71 includes a document reading section 73 and an image forming section 74. Note that, in FIG. 12, the document reading unit 73 and the image forming unit 74 are separated for easy understanding of the configuration.

The original reading section 73 is an optical system including an exposure lamp 75 for exposing the original and an image forming element 76 such as a rod lens array for forming an image of reflected light from the original on an image sensor array described later. Image sensor array 77 for taking in as image data from the image of the reflected light
And an image reading device including the above.

The image forming section 74 includes a photoconductor 81 and a charging section 8.
2, an LED array 83, a developing unit 84, a transfer unit 85, a cleaning unit 86 and the like.

Next, an outline of the image forming operation will be described. First, the document G is fed by the feed roller 78,
While being conveyed by the conveying roller pair 79 and the conveying roller 80, the light from the exposure lamp 75 is reflected by the original G, and the reflected light is focused by the equal-magnification image forming element 76 to form an image on the image sensor array 77. . On the other hand, the surface of the photoconductor 81 is uniformly charged by the charging unit 82, and then exposed by the image light from the LED array 83 that emits light based on the image data read by the image sensor array 77 to form an electrostatic latent image. Is formed. Further, the charged toner is supplied from the developing unit 84 to the photoconductor 81 and adheres to the electrostatic latent image, so that a toner image is formed.

On the other hand, a sheet is fed from the sheet feeding cassette 87 to the image forming section 74 by a sheet feeding means (not shown), and the toner image is transferred onto the sheet by the transfer section 85. Then, the paper is separated from the photoconductor 81, and after the toner image is fixed,
The image is ejected from the image forming unit 74 to the ejection tray 88. In addition,
The cleaning unit 86 cleans the toner remaining on the surface of the photoconductor 81 after the transfer.

Next, an embodiment of the image reading apparatus of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the image reading apparatus comprises an image sensor array 77 consisting of scanning type image sensors 1 to 4, a memory control section 5, a memory 6, a main scanning signal generating section 7 and the like. The image is read while the original is conveyed in the lengthwise direction and scanned. The sub-scan may be performed by relatively scanning the document, and thus the document may be fixed and the optical system and the image sensor array 77 may be moved.

The image sensor array 77 is composed of four image sensors 1 to 4 arranged in parallel in the main scanning direction. The image sensors 1 to 4 receive the reflected light from the document by n photosensors such as phototransistors arranged in parallel in the main scanning direction and read the document in pixel units. The original of the size is readable.

The photosensors in the image sensors 1 to 4 output a light receiving signal (analog signal) corresponding to the light receiving level to the memory control section 5, and the image sensor 1
As shown in FIG. 2, every time the main scanning signal R from the main scanning signal generator 7 is received, 2, 3, ...
Scanning is performed up to the first and nth pixels, and the light reception signal of each pixel is output to the memory control unit 5. Image sensor 2
The same applies to ~ 4.

The main scanning signal generator 7 includes the image sensor 1
The main scanning signal R is synchronously output to each of the image sensors 1 to 4 in order to perform the main scanning by each of .about.4, and the main scanning signal R causes the light receiving signal from each of the image sensors 1 to 4 to the memory control unit 5. Are output synchronously. The memory control unit 5 sequentially reads the light receiving signals from the image sensors 1 to 4, converts the received light signals into digital data (image data), and stores the digital data (image data) in association with each block of the memory 6 as described later.

The memory 6 is composed of a plurality of block memories 611.
~ 644. Each block memory 611-644
Stores the image data corresponding to each photo sensor in each image sensor 1 to 4, and has n memory areas.

Further, each block memory 611-644
Is for storing image data read by four consecutive main scans in association with each of the image sensors 1 to 4. That is, the block memories 611 to 614 respectively store the image data read by four consecutive main scans of the image sensor 1, and similarly the block memories 621 to 624, 631 to 634, 641 to 64.
Image data read by four continuous main scans of the image sensors 2 to 4 are stored in 4, respectively.

Further, the memory control unit 5 reads out the respective image data stored in a predetermined order described later from the block memories 611 to 644 and outputs them as output data to the image forming unit 74.

Further, the block memories 611 to 644 from which the image data has been read are sequentially updated to the newly read image data. For example, when the image data of the first main scan is read from the block memory 611, the image data read by the image sensor 1 in the fifth main scan is written in the block memory 611.

Next, an example of the operation of the image reading apparatus will be described with reference to FIGS. Note that, as shown in FIG. 3, only the straight line S parallel to the main scanning direction is drawn on the original G, and the others are left as a white background. Further, it is assumed that the reading of the straight line S is started from the i-th main scan and ended at the (i + 2) -th time.

First, the case of reading image data in binary black and white will be described. In this case, the memory controller 5
The signal output of the image data from each photo sensor is binary (1
Bit) to digitize,
One of the n memory areas of each block memory 611 to 644 can store 1-bit binary data.

When the i-th main scanning is performed by the main scanning signal R from the memory control unit 5, the reading of the straight line S of the original G is started, and the image data read by the image sensors 1 to 4 is controlled by the memory. The unit 5 outputs and writes to the block memories 611, 621, 631, 641 respectively.

At this time, the movement in the sub-scanning direction causes the movement in FIG.
As shown in, the reading area of the image sensor 1 is inclined with respect to the straight line S. Therefore, the memory controller 5 converts the binary digital data of 1 bit, and 0 is written in the 1st to jth positions of the block memory 611, and 1 is written in the j + 1th to nth positions. Here, 0 corresponds to white image data (hereinafter referred to as white data) and 1 corresponds to black image data (hereinafter referred to as black data). It becomes like 611. The same applies to the image sensors 2 to 4.

In this way, the block memories 611,
The first to jth parts of 621, 631, 641 are white data,
Black data is written in +1 to n-th.

Next, in the (i + 1) th main scan, the image data of the straight line S is stored in the block memories 612, 622, 63.
2 and 642, respectively, and black data is written.

Further, in the (i + 2) th main scan, i
Similarly to the case of the main scanning for the first time, the block memory 61
Black data is written in the first to j-th lines of 3,623,633,643, and white data is written in the j + 1 to n-th lines.
Is finished reading.

Then, in the (i + 3) th main scan, the white data from the image sensors 1 to 4 is transferred to the block memory 6
14, 624, 634, and 644 are output and written, respectively, and in the (i + 4) th main scan, they are again written to the block memories 611, 621, 631, and 641,
Hereinafter, the same process is repeated.

By the above operation, image data is written in each block memory of the memory 6, as shown in FIG.

Next, regarding reading of image data, FIG.
Will be explained. Note that, in FIG. 6, for convenience of description, the block memories read at the same timing are arranged in the horizontal direction.

After the completion of the writing of the image data by the i-th main scanning, the reading of the i-th image data from the memory 6 is started. At the time of the i-th reading, the image data is read from the block memories 612, 623, 634, 641. At this time, the block memory 61
2, 623, 634 include (i-3), (i-2),
(I-1) White data is written by the main scanning in the first time.

Then, when the writing of the (i + 1) th image data is completed, the (i + 1) th reading is performed, and the block memories 613, 624, 631, 642.
The image data from is read. At this time, white data is written in the block memories 613 and 624 by the (i-2) and (i-1) th main scanning.

Next, when the writing of the (i + 2) th image data is completed, the (i + 2) th reading is performed, and the block memories 614, 621, 632, 643.
The image data from is read. At this time, the white data of the (i-1) th main scan is written in the block memory 614.

Further, when the writing of the (i + 3) th image data is completed, the (i + 3) th reading is performed, and the block memories 611, 622, 633, 644 are executed.
The image data from is read. Next, when the writing of the (i + 4) th image data is completed, the (i + 4) th reading is performed, and the block memories 612 and 62 are
The image data from 3,634,641 is read.
At this time, the white data by the (i + 4) th main scan is written in the block memory 641. And
When the (i + 5) th writing of the image data is completed,
The (i + 5) th read is performed, and the image data is read from the block memories 613, 624, 631, 642. At this time, the block memories 631, 642
In, white data is written by (i + 4) and (i + 5) th main scanning.

By the above operation, the discontinuity of the read image data is eliminated as shown in FIG.

Next, a case of reading multi-valued (8-bit) image data in order to obtain image gradation data will be described. In this case, the memory control unit 5 is adapted to digitize the signal output of the image data from each photo sensor with 8 bits, and each block memory 611.
Up to 644 of the above n memory areas can store 8-bit data. Note that the image reading by the image sensors 1 to 4, the reading of the stored image data, and the like are basically performed by the same operation as in the case of the above-described binary.

In this case, in the i-th main scan, the reading area of the image sensor 1 is inclined with respect to the straight line S, as in the case of the binary value described above. Therefore, the memory control unit 5
Is converted into 8-bit digital data in the block memory 611, and 00H is stored in the block memory 611 between the 1st and the nth.
To FFH are written. Here, 00H is associated with white data and FFH is associated with black data, and the gradation data is represented by 01H to FEH in the meantime. When this is represented in the figure, the block memory 6 in FIG.
It becomes like 11. The same applies to the image sensors 2 to 4.

Then, i to (i +
3) The image data is written in the memory 6 as shown in FIG. 9 by the main scanning for the sixth time, and when the image data is read out in the order as shown in FIG. 10, the discontinuity as shown in FIG. 11 is eliminated. Output data is obtained.

As described above, even when the straight line S drawn on the original G is read by the plurality of image sensors 1 to 4, the read image data becomes a straight line without a step, so that the reproducibility and appearance are improved. A good image can be formed. Note that the image data after reading is inclined as shown in FIGS. 7 and 11, but the length of the photosensor in the sub-scanning direction is extremely smaller than the length of the image sensor in the main-scanning direction. However, the above inclination is also extremely small and does not hinder practical use.

It is to be noted that divided memories are provided for the image sensors 1 to 4, and the image data of the divided memories are output in parallel to the image forming section 74 while performing the same image data reading process as described above. You may do it.

The number of block memories of the memory 6 is not limited to the above. For example, if n image sensors are arranged side by side, n × n block memories may be provided.

[0049]

As described above, according to the present invention,
The image signal captured by the second image sensor is
The first and second memory blocks and the third and fourth memory blocks are alternately written for each scan, and the third and second memory blocks are written.
Since the image signal stored in the memory block and the image signal stored in the first memory block and the fourth memory block are read alternately, the reproducibility and appearance of the image signal can be improved. be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a timing chart showing a read timing from the image sensor.

FIG. 3 is an explanatory diagram showing a positional relationship between an image sensor and a document.

FIG. 4 is a straight line S read by the image sensor in the i-th main scan when image data is read in binary (1 bit).
3 is an explanatory diagram showing a memory block in which image data of FIG.

FIG. 5 is an explanatory diagram showing a memory in which image data read by an image sensor when image data is read in binary (1 bit) is written.

6 is an explanatory diagram showing an order of reading image data from the memory of FIG.

FIG. 7 is an explanatory diagram showing an image on which the read image data is printed.

FIG. 8 is a straight line S read by the image sensor in the i-th main scan when image data is read in multi-value (8 bits).
3 is an explanatory diagram showing a memory block in which image data of FIG.

FIG. 9 is an explanatory diagram showing a memory in which image data read by an image sensor when image data is read in multi-value (8 bits) is written.

10 is an explanatory diagram showing an order of reading image data from the memory of FIG.

FIG. 11 is an explanatory diagram showing an image on which read image data is printed.

FIG. 12 is a perspective view showing a schematic configuration of an image forming apparatus to which the image reading apparatus of the present invention is applied.

FIG. 13 is an explanatory diagram showing an image printed by a conventional image reading device.

[Explanation of symbols] [Explanation of symbols]

1-4 image sensor 5 memory control unit 6 memory 7 main scanning signal generation unit 611-614, 621-624, 631-634, 6
41-644 Block memory G Original S Straight line

Claims (3)

[Claims] 1. An image reading apparatus for reading an image of an original by moving the original relative to the original in the lengthwise direction of the original, receives reflected light from the original, and generates an image signal corresponding to the intensity of the original. First image sensor and second image sensor arranged in a row in the width direction, which have photoelectric conversion elements No. 1 to n arranged in a row in order from the front, and photoelectric conversion elements of each image sensor. Scanning means for scanning the columns in the direction from number 1 to number n at a predetermined speed in synchronization with each other, storage means having first, second, third and fourth memory blocks, and the first and second image sensors Writing the image signal captured by the first and second memory blocks according to the scanning direction, and setting the image signal captured by the first and second image sensors in the scanning direction. Therefore, writing means for alternately performing the operation of writing in the third and fourth memory blocks for each scan, and reading the image signals stored in the third memory block and the second memory block in the written order And a reading unit for alternately performing the operation and the operation of reading the image signals stored in the first memory block and the fourth memory block in the order in which they are written, and the first and second image sensors include the second unit. An image reading apparatus, wherein the first photoelectric conversion element of the image sensor is arranged next to the nth photoelectric conversion element of the first image sensor. 2. The reading means continuously reads the image signals stored in the third memory block and the second memory block in the order in which they are written, and stores them in the first memory block and the fourth memory block. The image reading apparatus according to claim 1, wherein the image signals are continuously read in a written order. 3. The reading means synchronously reads the image signals stored in the third memory block and the second memory block in the order in which they are written, and stores them in the first memory block and the fourth memory block. The image reading apparatus according to claim 1, wherein the image signals are read out in synchronism with the written order.