JPH08116411A - Original reader - Google Patents

Abstract

PURPOSE: To read a lengthy original by reading the original at constant speed and storing image data tentatively to a buffer of a prescribed capacity smaller than that of a page memory. CONSTITUTION: The reader is provided with a scanner, a buffer, a coder, a memory and a CPU. A state button is depressed at the time t0 (A) to set a line synchronizing signal (B) used to start the scanner, an image data output signal (C) and a coder operating signal (D) to start a coder to a high level at a time t1 . When the buffer is idle, the compression coding is stopped for a prescribed clock S1. The line synchronizing signal and the image data output signal are set to a low level at the time t6 and the coder operating signal is set to a low level at the time t7 . The scanner and the coder are started to apply compression coding to image data sequentially and the coded data are stored in the memory, then a lengthy original is read.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading device, and more particularly to a document reading device which conveys a document at a constant speed and reads the document.

[0002]

2. Description of the Related Art In recent years, a document reading apparatus such as a facsimile has been developed which is provided with a page memory capable of conveying a document at a constant speed to read the document and storing image data for one page of the read document. This document reading device conveys a document at a constant speed, reads the document, temporarily stores image data for one page in a page memory, encodes the image data, and stores the code data in the memory.

When the page memory is used in this manner, it is not necessary to stop the reading operation during the reading of one page of a standard size document (for example, A3, A4, etc.), so that the time required for reading is shortened.

Document reading devices for reading a document at a constant speed are disclosed in Japanese Patent Laid-Open Nos. 4-373248 and 4-43.
-373251, JP-A-4-373252, JP-A-4-373261, JP-A-5-030
262, JP-A-5-030307, and JP-A-5-030308.

[0005]

However, in the document reading apparatus which stores the read image data in the page memory, only the image data having a predetermined capacity can be input. Therefore, image data exceeding this capacity cannot be read. Further, in a document reading apparatus that conveys a document at a constant speed, the document reading cannot be interrupted during the reading, so that it is not possible to wait for the recovery of the capacity of the page memory.

Therefore, in the above-mentioned document reading apparatus which conveys a document at a constant speed to read the document and store the image data in the page memory, the length of the readable document is limited.

For example, a standard size document of A3 size has a resolution of 4
When accumulating at 00 ppi, the capacity of this page memory is designed to be about 4 Mbytes as shown in the equation (1).

(297 mm × 420 mm) × 15.748 dots / 8 bits = 3927 Kbytes (1) Therefore, read a document that exceeds approximately 4 Mbytes. I can't.

The length of a document that can be stored in a 4 Mbyte page memory is as follows when the resolution is 400 ppi.
It can be obtained by the equation (2).

(Length of storable original) ≦ (4 Mbytes / reading width) (2) The present invention has been made to solve the above problems, and the original reading is interrupted. An object of the present invention is to provide a document reading device that can read a document (hereinafter referred to as a long document) longer in one direction than a standard document at a constant speed.

[0011]

In order to achieve the above object, the invention of claim 1 conveys a document at a constant speed until the trailing edge of the document is detected, reads the document, and outputs image data. A moving original reading unit, a buffer storage unit having a predetermined capacity for temporarily storing the image data, and the image data compressed and encoded based on the amount of the image data stored in the buffer storage unit. Along with
A compression coding means for temporarily stopping the compression coding and a memory means for storing code data compressed and coded by the compression coding means are provided.

According to a second aspect of the present invention, an original moving type original reading unit that conveys an original at a constant speed to read the original, and outputs the image data, and a predetermined capacity for temporarily storing the image data. Buffer storage means, compression encoding means for compressing and encoding the image data based on the amount of image data stored in the buffer storage means, and temporarily stopping the compression encoding; Memory means for storing code data compression-encoded by the encoding means, input means for inputting range information corresponding to the reading range of the document, and reading corresponding to the range information input by the input means Control means for controlling the compression encoding means so as to compress and encode the image data in the range.

[0013]

According to the document reading apparatus of the present invention, the document reading means conveys the document at a constant speed until the trailing edge of the document is detected, reads the document and outputs image data, and the image data has a buffer of a predetermined capacity. It is temporarily stored in the storage means. The compression encoding means compresses the image data based on the amount of the image data stored in the buffer storage means, and temporarily stops the compression encoding. The code data compression-coded by the compression-encoding means is stored in the memory means.

Since the original is read until the trailing edge of the original is detected, the entire original can be read.

According to the document reading apparatus of the second aspect, the range information corresponding to the reading range of the document is input by the input means. The document is conveyed by the document reading unit at a constant speed, the document is read, image data is output, and the image data is temporarily stored in a buffer storage unit having a predetermined capacity. The compression encoding means compresses the image data based on the amount of the image data stored in the buffer storage means, and temporarily stops the compression encoding. At this time, the compression encoding means is controlled by the control means so as to compression encode the image data of the reading range corresponding to the range information input by the input means. The code data compression-coded by the compression-encoding means is stored in the memory means.

As described above, the compression encoding means is controlled so as to compression encode the image data of the reading range corresponding to the range information inputted by the input means, so that the memory means corresponds to the reading range of the original. Only the code data to be stored can be stored.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, the present invention is applied to a facsimile machine and a copying machine (hereinafter simply referred to as a facsimile machine).

As shown in FIG. 1, this facsimile apparatus includes a scanner 10 as a document reading means for reading a document at a constant speed and outputting image data, and the scanner 10 is connected to a bus 40. The scanner 10
It is connected to a buffer 12 for temporarily storing the image data output by the scanner 10 with a predetermined capacity smaller than the amount of image data for one page of the original. This buffer 12 is connected to the bus 40 and
It is connected to an encoder 14 as an encoding means for compressing and encoding the image data output from the. The encoder 14 is connected to the bus 40. This encoder 14
The code data compressed and encoded by the
The code data is stored in the memory 16 as a memory means such as a DRAM or a hard disk that stores a large amount of code data.

Further, this facsimile apparatus is provided with a key input section 32 provided on a control panel (not shown) for setting a document reading mode (hereinafter referred to as a reading mode) such as resolution and magnification. The key input unit 32 is connected to the control unit 30 of the panel that controls the entire operation panel. The control unit 30 of the panel is connected to the bus 40 and also to the display unit 34 for displaying the reading mode.

Further, the bus 40 is connected to a modem 36 that modulates / demodulates the code data stored in the memory 16. The modem 36 is connected to a line control unit 38 that inputs / outputs a network-controlled (NC) digital signal to / from a public line 42 (may be a dedicated line). In addition, the bus 40
It is connected to a decoder 24 which decodes the coded data stored in the memory 16 into image data. The decoder 24 is connected to a buffer 26 that temporarily stores the decoded image data. This buffer 26 is
It is connected to a printer 28 that prints a copy of the document.

Further, the facsimile apparatus of this embodiment is
A CPU 18, a ROM 20, and a RAM 22 are provided, each of which is connected to the bus 40. This R
The OM 20 stores a processing program described later and the like.

As shown in FIG. 2, the scanner 10 of the present embodiment is a movable document type having an automatic document feeding mechanism (ADF), and is a document placing table 4 on which a document 46 is placed.
4, a pair of rollers 48 for drawing in the document 46, a registration sensor 50 for detecting the leading edge of the document 46, a line image sensor 54 for reading each line of the document, and a white plate 52. The white plate 52 is fixedly installed right above the line image sensor 54 to prevent the original from floating and is used as a reference plate for white correction before the start of reading.

Further, the scanner 10 has an irradiation lamp 56 for irradiating a document, a pair of rollers 58 for discharging the document 46, an exit sensor 46 for detecting the trailing end of the document, and the document after the reading. A document receiving table 62 for placing the document is provided.

When one or more originals are placed on the original placing table 44 of the scanner 10 and a start button (not shown) is pressed, the first original 46 is drawn by the roller 48 and the registration sensor 50 is turned on. Manuscript 46
Reaches the top of the line image sensor 54. The original 46 irradiated by the irradiation lamp 56 is read line by line by the line image sensor 54, and after the leading end of the original 46 reaches the roller 58, the original power of the roller 58 passes through the exit sensor 60 and the reading is completed. 46
Is discharged to the document receiving tray 62. Then, the second and subsequent documents are read in the same procedure as the first document.

Therefore, in the scanner 10 of the present embodiment, the document is read during the document reading from the time when the leading edge of the document 46 reaches the line image sensor 54 to the time when the trailing edge of the document 46 passes over the line image sensor 54. 46 is conveyed at a constant speed.

As shown in FIG. 3, this scanner 10
Is electrically connected to the line image sensor 54, CCD control unit 64, image control unit 66, CPU 68, ROM 70, motor driver 72, motor 74, I / O interface unit 76, sensors 78 and lamp ballast 80. .

The black and white image information signal read by the line image sensor 54 is converted into an electric signal, and the CCD control unit 6
In 4, the signal is A / D converted into a digital signal after analog processing such as noise removal. The white correction unit 66A in the image control unit 66 corrects the irradiation light amount difference, the digital signal 66B waveform-shapes the digital signal, and the SG unit 66C performs density processing and binarization.

In the digital signal output from the SG unit 66C (see FIG. 4D), one bit is assigned to one pixel, and the bit corresponding to the synchronous clock signal shown in FIG. A number (a signal representing white or black) is transmitted in sequence, the effective portion is taken out by the line synchronization signal shown in FIG. 4B, and the binarized image data is stored in the buffer 12 bit by bit. . The data bus 40
Is connected to the I / O interface section 76, and the CPU 1
8 is an image data output signal (see FIG. 6).
Scanner 1 only when (see (C)) is at high level
0 outputs the image data to the buffer 12.

In this embodiment, the CPU 68 executes the process shown in FIG.
The synchronous clock shown in (A) is output at 5 MHz,
The time required to transfer one pixel is 0.2 μs.
The number of dots per line is A when the width of the document 46 is
3, when the resolution is 400 ppi, it is 4864 dots. Therefore, the transfer time per line is calculated by the equation (3).

0.2 μs × 4864 = 972.8 μs (3) Since the time for which the line synchronization signal is at the low level for one line is set to 27 μs, it is necessary to read one line. Time is about 1m as calculated by equation (4)
s.

972.8 μs + 27 μs = 999.8 μs (4) The following Table 1 shows an example of the reading mode that can be entered by the operator from the key input unit 32.

[0032]

[Table 1]

In the present embodiment, as shown in Table 1 above, the reading modes that can be input from the key input unit 32 include the document size, the designated page, the range information, and the composition.

As items, the document size includes A3, A4,
There are B4 and long originals, which can be selected respectively. The item range information includes the number of starting lines and the number of ending lines. The number of start lines is for designating a reading start position B described later, and the number of end lines is for designating a reading end position E described later (see FIG. 10). The item designation page is for designating on which page of the document the range information is set. A plurality of designation pages and range information can be designated.

In addition, there is nothing and existence in the composition of items,
Each can be selected. For example,
When this compositing is selected in the copy mode to be described later, as shown in FIG. 11, the reading range A of a predetermined page of the document and the reading range B of another predetermined page are combined and printed. .

The key input section 32 can also be used to input resolution, reduction ratio, density, distinction between character and photograph, etc., as in a general document reading apparatus. Further, the document sizes and the like shown in Table 1 are for facilitating the understanding of the contents of the present embodiment, and are not limited to these.
For example, B5 may be added to the document size item, or the reading range may be designated as an area (input coordinates).

The facsimile apparatus of this embodiment is capable of both facsimile (facsimile mode) and copying (copy mode). The copy mode and the facsimile mode will be described.

First, the operator places one or a plurality of documents on the document mounting table 44 of the scanner 10. And
The operator sees the display on the display unit 34 while watching the key input unit 3
After the selection of the copy mode or the facsimile mode and the reading mode such as the magnification and the size of the sheet are set by 2, the start button (not shown) is pressed to activate the facsimile apparatus.

When the copy mode is input from the key input unit 32, the image data read by the scanner 10 is encoded by the encoder 14 and stored in the memory 16. The coded data stored in the memory 16 is decoded into image data by the decoder 24 and then output to the printer 28 via the buffer 26. In this way, the original is copied. In this embodiment, when a plurality of originals are placed on the original placing table 44, the so-called sort copy method in which the originals 46 are read in ascending order and printed on the paper in descending order can be adopted.

On the other hand, when the facsimile mode is input from the key input unit 32, the code data stored in the memory 16 is modulated by the modem 36 and then output to the public line 42 through the line control unit 38. . In this example,
A so-called memory storage type transmission (transmission reservation) system in which code data is stored in the memory 16 and then transmitted can be adopted, and time designation transmission or broadcast transmission can also be performed by this system.

Next, the operation of this embodiment will be described. In the present embodiment, a standard document or a long document is read according to the reading mode input from the key input unit 32, and the code data thereof is stored in the memory 16.

When the power of the facsimile machine is turned on,
When the document reading process routine of FIG. 12 is executed and a start button (not shown) of the key input unit 32 is pressed (step 200), the reading mode is fetched from the control unit 30 of the panel in the next step 202.

Next, at step 204, it is judged whether the document size is a standard size (A3, A4, or B4). In the case of affirmative determination, A3 and A which will be described later in step 208.
Standard document mode processing for reading standard documents such as 4 (see FIG. 1)
3) is performed to end the processing routine. On the other hand, in the case of negative determination, it is determined in the next step 206 whether range information has been input. When a negative determination is made in step 206, a long document rear edge detection mode process (see FIG. 14) for reading a long document from the document front edge to the document rear edge, which will be described later, is performed in step 210, and the processing routine ends. On the other hand, if an affirmative decision is made in step 206,
Processing of a long document range designation mode for reading a reading range of a long document described later in step 212 (see FIG. 15)
Then, the processing routine is ended.

The details of step 208 will be described. In step 208, a subroutine for reading the standard size document shown in FIG. 13 is started.

First, in step 300, the line sync signal and the image data output signal for outputting the image data to the buffer 12 are set to a high level. As a result, the scanner 10 reads the document line by line and outputs the image data to the buffer 12.

At the next step 302, the encoder operation signal for activating the encoder 14 is set to the high level. As a result, the encoder 14 starts compression encoding of the image data output from the buffer 12.

In the next step 304, it is judged whether or not the reading of one page of the original has been completed by the detection or non-detection of the rear end of the original by the exit sensor 60 (see FIG. 2). When the affirmative judgment is made in step 304, the routine proceeds to step 310, and when the negative judgment is made, the routine proceeds to next step 306.

In step 306, it is determined whether or not the buffer 12 is empty (no image data). When the determination is affirmative, the encoder operation signal is set to low level in the next step 308 to maintain low level for a predetermined clock. do it,
Return to step 302.

The determination in step 306 is based on the buffer 1
This is to prevent the compression encoding from being performed assuming that the image data (see FIG. 4C) is input while 2 is empty. On the other hand, when a negative determination is made in step 306, the process returns to step 304.

In step 310, the line sync signal and the image data output signal are set to low level. As a result, the scanner 10 finishes reading the document.

In the next step 312, it is judged whether or not the buffer 12 is empty, and if it is empty, the encoder operation signal is set to the low level in the next step 316. As a result, the encoder 14 ends the compression encoding. On the other hand, when it is determined in step 312 that the encoder is not empty, the encoder operation signal is maintained at the high level, and the compression encoding by the encoder 14 is continued until the buffer 12 is empty.

In the next step 318, it is judged whether or not there is a manuscript of the next page, that is, whether or not the registration sensor 50 (see FIG. 2) has detected the manuscript of the next page, and in the case of a negative judgment, This processing routine ends. On the other hand, if the determination is affirmative, the process returns to step 300, and the original of the next page is processed in the same manner as above.

The timing of the above processing routine will be described in detail. As shown in FIG. 6 (A), the start button is pressed at time t ₀ (step 200), FIG. 6 (B),
As shown in (C) and (D), the line sync signal, the image data output signal, and the encoder operation signal are set to the high level at time t ₁ (steps 300 and 302).

When the buffer 12 becomes empty at time t ₂ , time t ₃
The compression encoding is stopped during the predetermined clock S1 up to (steps 306 and 308). This means that time t ₄ and time t ₅
Is the same. At time t ₆ the line synchronizing signal and the image data output signal is driven to a low level (step 310), the encoder operation signal is set to low level at time t ₇ (step 312, 314, 316).

Next, the details of step 210 will be described.
In step 210, as shown in FIG. 14, a subroutine for reading is executed until the trailing edge of the long document is detected. This is the scanner 10 as shown in FIG.
Is to start reading from the leading edge F of a long document and continue reading until the trailing edge R is detected.

In step 320, a limit line number n, which is a limit line number that can be counted by a counter (not shown) of the encoder 14, is initialized. That is, when a long original is read, the number of processing lines e compression-coded by the encoder 14 exceeds the limit number of lines n, and a counter (not shown) may not be able to count. Therefore, in step 320, the limit line number n is initialized, the counter is reset when the process line number e exceeds the limit line number n, and the CPU 18 adds the process line number each time the reset line number is reset. The total number of processing lines is counted by the encoder 14
It is possible to read the original with the number of processing lines larger than the limit number of lines.

In the next step 300, the line sync signal and the image data output signal for outputting the image data to the buffer 12 are set to the high level, and the step 30
In step 2, the encoder operation signal is set to high level, and in step 3
In step 22, the number of processing lines e compressed and encoded is counted.

Next, at step 324, the number of processing lines e
Is equal to the limit line number n. If an affirmative decision is made, in step 326 the encoder operation signal is set to a low level, the limit line number n is reset (the counter is initialized again, and the total number of processing lines of the encoder 14 is counted), Return to step 302. On the other hand, when a negative determination is made in step 326, the next step 3
At 28, it is determined whether the exit sensor 60 (see FIG. 2) has detected the trailing edge of the document.

In step 328, if the affirmative judgment is made, the routine proceeds to step 310, and if the negative judgment is made, the routine proceeds to step 306.

In step 306, it is determined whether or not the buffer 12 is empty, and if the determination is affirmative, the next step 308
In step 3, the encoder operation signal is set to the low level to maintain the low level for a predetermined clock, and the process returns to step 302. When the determination is negative, the process returns to step 302. Note that the processing after step 310 is the same as that in the case of FIG. 13, so description thereof will be omitted.

The timing of the above processing routine will be described in detail. As shown in FIG. 7 (A), the start button is pressed at time t ₀ (step 200), FIG. 7 (B),
As shown in (C) and (D), the line sync signal, the image data output signal, and the encoder operation signal are simultaneously set to the high level at time t ₁ (steps 300 and 30).
2).

When the buffer 12 becomes empty at time t ₂ , time t ₃
The compression encoding is stopped during the predetermined clock S1 up to (steps 306 and 308). This means that time t ₄ and time
t _5, time t ₈ and time t _9, the time t ₁₀ and time t _11, the time t ₁₄ and time t ₁₅ and time t ₁₇ and time t _{1 8,} the same for.

At time t ₆ , the processing line number e is the limit line number n.
When it becomes equal to, the limit line is reset for a predetermined clock S2 until time t ₇ (steps 324, 32).
6). This is the same for time t ₁₂ and time t ₁₃ .

At time t ₁₆ , the line sync signal and the image data output signal are set to the low level (step 31
0), the encoder operation signal is set to the low level at time t ₁₉ (steps 312, 314, 316).

Next, the details of step 210 will be described.
In step 210, as shown in FIG. 15, a subroutine of the range designation mode process of the long document is executed.
As shown in FIG. 10, this is to read a reading range from a predetermined reading start position B to a predetermined reading end position E of a long document.

In step 320, the limit number of lines n is fetched, and in the next step 330, the key input unit 32
The number m of lines to be skipped and the number k of read lines (see FIG. 10) are calculated from the range information input from.

Next, at step 332, the line sync signal is set to high level. This causes the document 46 to start moving in a predetermined direction (direction of arrow A in FIG. 10).

In step 334, the number l of lines moved by the scanner 10 is counted, and in the next step 335, it is determined whether or not the number l of lines is equal to the number m of lines to be skipped. If an affirmative decision is made, in the next step 336 the image data output signal is made high. As a result, the reading is skipped from the leading edge of the document to the number of lines m, and the image data from the reading start position B (see FIG. 10) is output. On the other hand, when a negative determination is made in step 335, since the reading start position B has not been reached, the process returns to step 334.

In step 338, the encoder operation signal is set to high level. As a result, the encoder 14 starts the compression encoding and the counting of the number of processing lines e.

At the next step 340, the number of processing lines e
Is equal to the limit line number n. When a positive determination is made, the encoder operation signal is set to low level in step 326, the limit line number n is reset, and the process returns to step 338. On the other hand, when a negative determination is made, it is determined in the next step 342 whether or not the line number 1 is equal to the sum of the skipped line number m and the read line number k, and the read end position E (FIG. 10). Refer to the above).

If an affirmative decision is made in step 342, the operation proceeds to step 310. On the other hand, step 34
When a negative decision is made in step 2, the next step 306
Go to.

In step 306, it is determined whether or not the buffer 12 is empty. If the determination is affirmative, then the next step 308
In (3), the encoder operation signal is set to the low level and maintained at the low level for a predetermined clock, and the process returns to step 338. When the determination is negative, the process returns to step 340. Note that the processing after step 310 is the same as that in the case of FIG. 13, so description thereof will be omitted.

The timing of the above processing routine will be described in detail. As shown in FIG. 8 (A), the start button is pressed at time t ₀ (step 200), and as shown in FIG. 8 (B). , The line sync signal is set to high level at time t ₁ . As shown in FIGS. 8C and 8D, the time
At t ₂ , the image data output signal and the encoder operation signal are simultaneously set to the high level (steps 336 and 33).
8). In this way, since the image data is not output from time t ₁ to time t ₂ , the number of lines m is skipped. The compression coding stop time S1 and the limit line resetting time S2 are the same as those described with reference to FIG.

At time t ₁₁ , when the number of lines counted from time t ₁ becomes (m + k), the line sync signal and the image data output signal are set to low level (step 310).
At time t ₁₂ , the encoder operation signal is set to the low level (steps 312, 314, 316).

Although the range information is input by the number of lines in this embodiment, the reading start position or the reading end position may be specified by a length of several centimeters from the leading edge of the document.

Further, in the present embodiment, the range information is designated with the leading end as the reference, but it may be designated with the trailing end as the reference.

Further, in the present embodiment, an example in which the image data is output from the range start position has been described. However, the number of start and end lines to be compression-encoded is calculated in advance, and the encoder 14 calculates the read range. The image data may be compression-encoded.

The encoding system of the encoder 14 is as follows.
Any one of so-called modified Huffman (MH), modified read (MR), modified modified read (MMR), and the like can be used.
Coded data obtained by these coding methods are not fixed lengths, and the time required for compression is different, so the time for processing one line is not constant. Therefore, in the present embodiment, the worst speed of the encoder 14 (so-called 1 bit in which white and black alternately appear every 1 bit shown in FIG. 4D in the case of compressing and encoding one line at the latest time) (When the image information of the ladder) is set to 1.25 ms / line,
The maximum speed (when one line is compressed and coded at the earliest time and in the case of the image information shown in FIG. 4D in which only white and black does not appear) is set to 0.5 ms / line.

Further, in this embodiment, the buffer 12 having a capacity of about 800 Kbytes is used. Also, when the address value of this buffer 12 increases and reaches the last address,
The next address is operated as a so-called ring buffer in which the first address is designated. Therefore, it is possible to prevent the overflow of the image data temporarily stored in the buffer 12 when the encoder 14 is performing the compression coding at the worst speed.

The capacity of the buffer 12 required for each line when the encoder 14 operates at the worst speed is obtained by the equation (5). As described above, the reading speed of the scanner 10 is about 1 ms / line, and the image data amount that cannot be processed when the encoder 14 is compression-coding at the worst speed of 1.25 ms / line is 0.25 ms for 1 ms. There are 4864 dots per line.

4864 × 0.25 ÷ 1.25 ÷ 8 = 121.6 (bytes) (5) Since 6614 lines can be read with A3 paper and a resolution of 400 ppi, it is the maximum at the end of reading for the entire A3 paper. Then, the number of bytes in Expression (6) is stored in the buffer 12.

121.6 bytes × 6614 = 804262.4 bytes (6) = 785.4125 Kbytes Therefore, if the capacity of the buffer 12 having a capacity of about 800 Kbytes is used, one page of an A3 original document is included in a long document. Even if the minute range is in the 1-bit ladder state described above, the image data does not overflow. Further, the state of the 1-bit ladder does not continue from the leading edge to the trailing edge of the long document, and further works to reduce the image data temporarily stored in the buffer 12 (compression coding average speed of the encoder 14). Is designed to be at the maximum speed side rather than the worst speed side), so that the buffer 12 does not overflow even for a long original that exceeds one A3 original page.

Buffer 1 having a capacity of about 800 Kbytes
2 is much smaller than a page memory (capacity: 3927 Kbytes) that can store image data for one page of a document used in a general facsimile apparatus. Therefore, in this embodiment, the product cost can be reduced. The capacity of the buffer 12 is not limited to 800 Kbytes, and may be less than 800 Kbytes.

In the facsimile apparatus using the page memory as described above, since the sequential processing is performed as shown in FIG. 5, the reading start time t1 to the reading end time
It is the total of the reading processing time A up to t2, the control processing time p by the CPU from the reading end time t2 to the coding start time t3, and the compression coding processing time B from the coding start time t3 to the coding end time t4. Processing time X is required. On the other hand, in this embodiment, the reading by the scanner 10 and the encoder 1
4 and the compression encoding by 4 are activated at the same time to perform parallel processing (see FIG. 6). Therefore, the processing time Y required to process one page of the original document is the reading processing time C + the encoding delay time Q.
(Time to process the image data remaining in the buffer 12), and the processing time from the document reading to the compression encoding is shortened as compared with the case where the page memory is used.

As described above, according to this embodiment, the buffer 1
Since the image data temporarily stored in 2 is compressed and encoded by the encoder 14 and stored in the memory 16, the original can be read until the trailing edge of the original is detected. As a result, a long original can be read and the buffer capacity can be economically designed even if the scanner for conveying the original at a constant speed and reading the original has a smaller buffer capacity than the page memory.

Since the encoder 14 compresses and encodes the image data of the range information corresponding to the reading range input by the key input unit 32, only the code data of the reading range can be stored in the memory 16. . As a result, the memory 16 can be effectively used, paper can be saved in the copy mode, and communication time can be shortened in the facsimile mode.

Further, even when the encoder 14 has a limit on the number of limit lines that can be processed, the limit line can be reset, so that it is possible to read a long original beyond the limit number of lines.

[0088]

As described above, according to the first aspect of the invention, since the original is read until the trailing edge of the original is detected, it is possible to obtain the effect that the entire original can be read.

According to the second aspect of the invention, the compression encoding means is controlled so as to compression encode the image data of the reading range corresponding to the range information inputted by the input means. Can obtain the effect that only the code data corresponding to the reading range of the original can be stored.

[Brief description of drawings]

FIG. 1 is a block diagram showing a copying machine / facsimile apparatus to which the present invention can be applied.

FIG. 2 is a configuration diagram showing a schematic configuration of a scanner of this embodiment.

FIG. 3 is a block diagram showing the electrical configuration of the scanner of this embodiment.

FIG. 4 is a timing diagram showing timings of a synchronization clock, a line synchronization signal, and an image information signal.

FIG. 5: Start button when using page memory,
It is a timing diagram which shows the timing of a line synchronization signal and an encoder operation signal.

FIG. 6 is a timing chart showing timings of a start button, a line synchronization signal, an image data output signal, and an encoder operation signal when reading a standard document.

FIG. 7 is a timing chart showing the timings of a start button, a line synchronization signal, an image data output signal, and an encoder operation signal when reading until the trailing edge of a long document is detected.

FIG. 8 is a timing chart showing timings of a start button, a line synchronization signal, an image data output signal, and an encoder operation signal when reading a reading range of a long original.

FIG. 9 is a conceptual diagram of a long original when reading is performed until the trailing edge is detected.

FIG. 10 is a conceptual diagram of a long original when reading a reading range.

FIG. 11 is a conceptual diagram when a document is combined.

FIG. 12 is a flowchart showing a flow of document reading processing according to the present embodiment.

FIG. 13 is a flowchart showing a subroutine of step 208 of FIG.

FIG. 14 is a flowchart showing a subroutine of step 210 of FIG.

15 is a flowchart showing a subroutine of step 212 of FIG.

[Explanation of symbols]

 10 Scanner (Original Reading Means) 12 Buffer (Buffer Storage Means) 14 Encoder (Compression Encoding Means) 16 Memory (Memory Means) 18 CPU (Control Means) 20 ROM (Control Means) 32 Key Input Unit (Input Means)

Claims (2)

[Claims] 1. A document moving-type document reading unit that conveys a document at a constant speed to read the document and outputs image data until a trailing edge of the document is detected, and a predetermined capacity for temporarily storing the image data. Buffer storage means, compression encoding means for compressing and encoding the image data based on the amount of image data stored in the buffer storage means, and temporarily stopping the compression encoding, A document reading apparatus comprising: a memory unit that stores code data that has been compression-encoded by the compression encoding unit. 2. A manuscript moving type manuscript reading unit that conveys a manuscript at a constant speed to read the manuscript and output image data, a buffer storage unit having a predetermined capacity for temporarily storing the image data, and the buffer. Compression encoding means for compressing and encoding the image data based on the amount of image data stored in the storage means, and temporarily stopping the compression encoding; and compression encoding by the compression encoding means. Memory means for storing the encoded data, input means for inputting range information corresponding to the reading range of the original, and image data of the reading range corresponding to the range information input by the input means A document reading apparatus comprising: a control unit that controls the compression encoding unit so that the data is encoded.