JP3154245B2 - Image processing 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 processing apparatus for performing a decoding process and a recording process in parallel using a small-capacity memory.

[0002]

2. Description of the Related Art In a facsimile apparatus using a constant-speed printing printer such as a laser beam printer as a recording unit, an image for one page of a printed image is stored as pixel data between a decoding unit and the printer. Page buffer.

[0003] How to use a page buffer in this type of apparatus will be described by taking a reception operation as an example. First, the code data received by the modem is temporarily stored as a code in the storage image memory. When the code data for one page is accumulated, the decoding unit sequentially retrieves the code from the accumulated image memory in parallel with the reception operation, and once restores all the data for one page to pixel data, and stores the data in the page buffer described above. Store.

When one page of pixel data to be printed is stored in the page buffer, the one page of pixel data is sequentially read from the page buffer, transferred to a printer, and printed.

[0005]

However, in the above conventional example, a memory for one page for storing the pixel data is required, and the required capacity increases according to the paper size and the pixel density. For example, even at the coarsest standard resolution (8 pel, 3.85 line / mm) in a facsimile machine, the amount of A4 size pixel data is as large as about 2 megabits, and the printing paper width is B4 size. Or the resolution is 7.71 line of fine resolution
In the case of / mm, there is a disadvantage that a larger memory is required.

[0006] Facsimile machines having a page buffer also have the following problems.

First, even if an error occurs in the received image data, the pixel data must be sent to the printer without delay.

Second, when the number of lines of received image data exceeds the number of lines of recording paper, the following processing has to be performed. (1) Divided printing is performed on two or more pages. (2) Printing is performed by appropriately reducing the size of the image and storing it within one page. (3) Printing is performed within one page by cutting off the trailing end.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has as its object to provide an image processing apparatus that performs a decoding process and a recording process in parallel using a plurality of line buffer memories.

[0010]

[0011]

To achieve the above object, according to the Invention The image processing apparatus according to the present invention, the content of the image data
Regardless, a decoding unit that decodes one line of encoded image data within a predetermined time , a plurality of lines of image data from the decoding unit are stored, and one page of image data is stored. a line buffer memory is not a page buffer for storing the line buffer memory 1
Synchronize with the timing of recording the line image data
Instead, while there is free space in the line buffer memory,
A plurality of lines of image data are continuously decoded by the decoding means.
It is Goka, If there is no empty, image data to said decoding means
Control means for controlling the decoding of the data to be interrupted;
At this time, one line of the image data read from the line buffer memory is recorded for a fixed time regardless of the content of the image data, and without interruption during the recording of one page of image data. A page printer that records image data on recording paper at a constant speed.

[0012]

[0013]

[0014]

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment according to the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a schematic block diagram showing a configuration of a facsimile apparatus in a first embodiment. In FIG. 1, reference numeral 1 denotes a system control unit, which controls the entire apparatus. Reference numeral 2 denotes a large-capacity image memory for storing image data in the form of compression-encoded data. 3
Denotes a decoding unit that decodes the compression-encoded data to restore the original pixel data. Reference numeral 4 denotes a buffer control unit which receives the pixel data restored by the decoding unit 3 and stores the pixel data at a predetermined address of a line buffer 5 described later and a process of outputting print pixel data to the print control unit 6 in a predetermined order. I do. Reference numeral 5 denotes a line buffer having a capacity to store print pixel data for a plurality of lines.

Reference numeral 6 denotes a print control unit which fetches print pixel data from the line buffer 5 at regular intervals and controls one-page uniform-speed transport printing processing. Reference numeral 7 denotes a page printer which prints pixel data while conveying a recording sheet at a constant speed. Reference numeral 8 denotes a DMA controller, which transfers the encoded data stored in the image memory 2 to the decoder 3 by a direct memory access (DMA) transfer method. An operation unit 9 includes an operation instruction button, a display, and the like. Reference numeral 10 denotes a modem (modem). Reference numeral 11 denotes a network control unit which controls connection with a public line. Reference numeral 12 denotes an encoding unit that performs compression encoding processing on pixel data to be transmitted. A reading unit 13 reads a document.

The signals a, b, c, d, e, and f in FIG.
Has the following meanings. a is a one-line decoding start signal that outputs a pulse every time the decoding unit 3 starts decoding one line, b is a pixel signal of a decoding result, and c is a sampling clock of the pixel signal b. d is a one-line print synchronization signal output by the print control unit 6 described above, e is print data output in synchronization with the one-line print synchronization signal d,
f is a buffer full signal output from the buffer control unit 4 and notifies the decoding unit 3 that the line buffer 5 does not have enough capacity to store new image data.

FIG. 2 is a data flow showing processing from data reception to printing of a general facsimile apparatus using a page printer. As shown, the page buffer corresponds to the line buffer 5 shown in FIG. 1, and each process is constituted by the following three means. (1) The code data received by the modem 10 is sequentially stored in the image memory 2. When at least one page of code data to be printed is stored in the image memory 2 in parallel with this processing, the following processing is performed. Will be (2) The accumulated code data is input to the decoding unit 3 and decoded, and the decoding process is repeated until print pixel data corresponding to one page of the recording paper is accumulated in the page buffer. (3) When one page of pixel data is accumulated in the page buffer according to the above (2), the decoding unit 3 stops the process, and the print control unit 6 changes in synchronization with the conveyance of the recording paper at a constant speed. The reading of the pixel data from the page buffer is repeated to print one page.

In the above description, the buffer controller 4 is omitted for simplicity.

On the other hand, FIG. 3 is a data flow showing each process from data reception to printing in the first embodiment. (1) Similar to the above-described data reception processing (1), when at least one page of code data to be printed is stored in the image memory 2 in parallel with this processing, the following processing is performed. (2) The decoding unit 3 starts decoding the encoded data, and starts accumulating the print pixel data in the line buffer 5. At the same time, the printing control unit 6 reads out pixel data sequentially from the line buffer 5 and executes printing processing for one page. Therefore, at this time, if the time required for the decoding process for one line is always faster than the printing time corresponding to one line of the print control unit 6, valid data is not lost in the line buffer 5.

FIG. 4 shows a page printer having a sub-scanning resolution of 15.4 line / mm and a sub-scanning resolution of 3.85 line / mm.
FIG. 8 is a diagram illustrating print dots when an image of mm, 7.7 line / mm is printed. As shown, sub-scan resolution 3.85 lin
When printing one line of an e / mm image, the sub-scanning resolution is 1
A 5.4 line / mm printer will print the same line four times in a row.

Therefore, in this case, the decoding unit 3 shown in FIG.
The pixel data of one line stored in the line buffer 5 after decoding is read out four times consecutively by the print control unit 6 and printed.

The image to be printed has a sub-scanning resolution of 7.7.
If it is line / mm, the same line will be printed twice.

Generally, the printing time for one line of a laser printer is about 2 msec. Therefore, in the case of an image of 7.7 line / mm, it suffices to complete decoding of one line in about 4 msec. The decoding unit that satisfies the speed condition of the decoding process can be sufficiently realized if its structure is configured by wired logic.

FIG. 5 is a timing chart for explaining the operations of the decoding section 3, buffer control section 4, and print control section 6 shown in FIG.

First, in response to the signal a, the decoding unit 3 instructs the buffer control unit 4 to start decoding a new line.
Notify to The buffer control unit 4 thereby updates the storage destination address of the restored pixel data in the line buffer 5 and updates a counter (not shown) for counting the number of unprinted lines remaining in the line buffer 5.
At this time, if there is not enough free space in the line buffer 5 to store a new line, the buffer control unit 4
, The output of the pixel data is temporarily stopped by the signal f.

Next, the decoding section 3 outputs the decoded pixel data as a signal b and its sampling clock as a signal c. The pixel data output as a result of the decoding is output intermittently because the code data is output while sequentially decoding the code data.

In this way, the line buffer 5
Lines, the (N + 1) th line, the (N + 2) th line,..., Continue until a line corresponding to one page of the recording paper is decoded.

On the other hand, the print control unit 6 outputs 1
A signal d indicating a line printing start timing is output,
The buffer controller 4 sequentially reads out the print image data from the line buffer 5 and outputs it as a signal e in synchronization with the signal d. At this time, the buffer controller 4 reads the same line a plurality of times as shown in FIG. 4 according to the preset sub-scanning resolution of the print image. FIG. 5 shows an example in which an image of 7.7 line / mm is printed on a printer of 15.4 line / mm.

As described above, each time reading and printing corresponding to one line are completed, the buffer control unit 4 updates the counter for counting the number of unprinted lines remaining in the line buffer 5.

[Modification of First Embodiment] In the first embodiment,
Although the data of the reference line used for the decoding process of the two-dimensional code is assumed to be inside the decoding unit 3, the data of the reference line may be read from the line buffer 5 every time the data is needed.

Further, in the first embodiment, since the resolution of the code data and the resolution of the printer are different, the data is read out and printed a plurality of times for each restored line from the line buffer 5. By changing every predetermined line, without completely thinning the restoration line,
Reduction in the sub-scanning direction can be performed.

Further, reduction in the main scanning direction can be easily performed by performing processing such as pixel thinning when storing the data in the line buffer 5 from the decoding unit 3. This kind of reduction processing at the time of printing is necessary because the size of the recording paper may be smaller than the image size reserved for memory transmission when trying to print out the image reserved for memory transmission. This is the process.

Although a page printer is assumed as a printing device, a line buffer 5 in the embodiment can be used in a thermal head printer capable of performing intermittent transport printing by a stepping motor using thermal roll paper or the like.
By using the configuration of the constant speed transport printing using the above, it is possible to eliminate the feeding unevenness caused by the feeding error of the stepping motor.

As described above, according to the first embodiment, a facsimile apparatus using a page printer can be constructed with an extremely small-capacity line memory regardless of the size and resolution of an image to be printed. There is an effect that can be reduced.

Second Embodiment Next, a second embodiment according to the present invention will be described in detail with reference to the drawings.

FIG. 6 is a schematic block diagram showing the configuration of the facsimile apparatus in the second embodiment. In the figure, reference numeral 21 denotes a main control unit which controls the entire apparatus. 2
A reading unit 2 reads image data on a document and outputs image data in the form of a binary signal. A communication unit 23 sends and receives data to and from another communication device via a communication line. Reference numeral 24 denotes a data processing unit which encodes and decodes image data. An image memory 25 stores encoded image data. A line memory control unit 26 receives pixel data from the data processing unit 24 and stores the pixel data in the line memory 27.
To output print pixel data. Reference numeral 27 denotes a line memory having a capacity to store print pixel data for a plurality of lines. Reference numeral 28 denotes a printer unit which performs constant speed printing.

Hereinafter, an example of the data flow at the time of reception will be described with reference to FIG.
The operation in the second embodiment will be described with reference to FIG.

FIG. 7 is a flowchart showing the operation of decoding the code data in the image memory 25 and supplying the data to the line memory 27. FIG. 8 shows the printer unit 2.
8 is a flowchart showing the operation of reading out pixel data from the line memory 27 and printing.

First, in step S11, the received data is temporarily stored as coded data in the image memory 25 via the communication unit 23 and the data processing unit 24, and when one or more pages are stored, the image data in the image memory 25 is stored in step S12. The encoded data is read by the data processing unit 24, sequentially decoded, and supplied to the line memory 27 from the line memory control unit 26. Then, in step S13,
It is determined whether the processing for one page has been completed. If the processing has not been completed, it is checked in step S14 whether or not there is a free space in the line memory 27.

On the other hand, the printer section 28 detects the upper end of the recording paper in step S21 shown in FIG. 8, and detects the left end of the recording paper in the next step S22. Next, in steps S23 and S24, the data sub-scanning resolution and the drawing sub-scanning resolution of the printer unit 28 are set to be the same.
The same line is read out from the line memory 27 corresponding to the ratio, and printing is performed at a constant speed in a fixed time for one line.

At this time, if the data processing unit 24 can supply the image data to the line memory 27 faster than the reading speed of the printer unit 28, the data in the line memory 27 will not be lost.

This condition is expressed by the following equation.

T (SUP) ≦ R × A × T (PRT) Here, T (SUP) is a time for supplying one line in the main scanning, T (PRT) is a printing time for one line in the main scanning of the printer, and A is a printer. / R is the sub-scanning density ratio between image data and R is the reduction ratio in the sub-scanning direction at the time of data printing.

As a specific example, recording paper sizes A4, T (P
RT) = 2.709 (ms), using a printer unit 28 with a sub-scanning recording density of 15.4 line / mm, B4 size, sub-scanning density of 7.7 line
An example in which data of / mm is printed will be described.

First, the sub-scanning density ratio is given by the following equation, and the printer unit 28 draws the same line of image data twice.

A = 15.4 ÷ 7.70 = 2.00 Next, since reduced printing of B4 → A4 is performed, R = 9/11
From T (PRT) = 2.709 (ms), T (SUP)
= 4.43 (ms), and if the time required for one-line decoding is always shorter than 4.43 (ms), the data in the line memory 27 will not be lost.

Actually, since data of a plurality of lines can be stored in the line memory 6, it can be considered as an average of the time required for one-line decoding. Need not be.

As described above, according to the second embodiment, the printer unit 28 reads data from the line memory 27 and performs a printing operation in parallel with the supply of data to the line memory 27 by the data processing unit 24. As a fixed small-capacity line memory irrespective of the size and resolution of an image to be printed on a large-capacity page buffer, the memory capacity can be reduced and the cost can be greatly reduced.

Third Embodiment Next, a third embodiment according to the present invention will be described in detail with reference to the drawings.

FIG. 9 is a schematic block diagram showing the configuration of the facsimile apparatus in the third embodiment. In FIG. 1, reference numeral 101 denotes a system control unit, which includes an MPU, a ROM,
It is composed of a RAM and the like, and controls the entire system. 1
A reading unit 02 reads a document and outputs pixel data as serial binary data. A serial-parallel (S / P) conversion unit 103 converts serial data from the reading unit 102 into parallel data and outputs the parallel data to a line memory 104 described later. A line memory unit 104 temporarily stores a plurality of lines of pixel data. 1
An encoding unit 05 reads predetermined pixel data from the line memory 104 and performs a compression encoding process. 106
Denotes a decoding unit, which decodes encoded data from the image memory 111 described later at high speed, and stores the decoded pixel data in the line memory 104. 107 is parallel-
It is a serial (P / S) conversion unit, and a line memory 104
While reading out predetermined pixel data from the memory and outputting the data as a serial signal, the main scanning is also reduced by a process such as thinning out pixels for each predetermined pixel according to an instruction from the system control unit 101 as necessary.

Reference numeral 108 denotes a line buffer control unit which converts the output of the parallel-serial conversion unit 107 into parallel data as input data,
09, and the second process of sequentially reading already stored pixel data from the line buffer 109 in synchronization with the line synchronization signal from the page printer 110, converting the data into serial data, and outputting the converted data. Run. If necessary, sub-scanning is also reduced by processing such as thinning out lines in a certain pattern according to an instruction from the system control unit 101. A line buffer 109 temporarily stores print pixel data of a plurality of lines. 110
Reference numeral denotes a page printer which outputs a synchronization signal having a constant period for each print line and prints serial pixel data output from the line buffer 109. Reference numeral 111 denotes an image memory unit which stores image data as compressed code data.
M and the like. A modem unit 112 transmits and receives data via a line, and modulates and demodulates the data. A network control unit (NCU) 113 controls an electrical interface with a line.

An operation console 114 comprises operation keys, a display, and the like. Reference numeral 115 denotes a registration memory unit, which is a memory for storing management information and the like necessary for controlling the present system. An image management data storage unit 116 stores information necessary for managing image data. 11
Reference numeral 7 denotes a command / status control unit, which performs interface control such as commands and status between the system control unit 101 and the page printer 110. Reference numeral 118 denotes a system bus, which is a bus connecting the system control unit 101 and each member. An image bus 119 is a bus for transferring image data. Reference numeral 120 denotes a line. The SYNC signal in the figure is the page printer 11
This is a one-line synchronization signal from 0.

The above-described decoding unit 106 always requires that the time required for decoding one line is sufficiently shorter than the printing time of one line of the page printer 110. Actually, such a thing can be sufficiently realized by configuring with a wired-OR logic circuit.

Hereinafter, the receiving operation of the facsimile apparatus in the third embodiment will be described.

Since the arrival speed of the coded data from the line does not match the printing speed of the page printer 110, a reception process of encoding and storing the received data in the image memory 111;
It is composed of two independent printing processes for printing an image stored in the image memory 111 on recording paper.

First, regarding the receiving process, the NCU 11
3. The decoding unit 106 sequentially decodes the received coded data obtained via the modem unit 112, and the coding unit 105 sequentially codes only normal lines except for error lines according to a predetermined code format. Then, the image data is stored in the image memory 111. Then, after receiving one page, the number of accumulated lines is counted and stored.

In order to determine the end of one page of the received image data, the RTC signal (CCI
TT-T. 4) may be detected.

Here, since the printing unit is a page printer that counts and stores the normal number of lines, it is necessary to determine before dividing the number of pages of the recording paper that one received page should be divided before printing. It is. Further, management information of the image memory is created in the image management data storage unit 116.

FIG. 10 is a diagram showing a format example of the management information described above. In the figure, one image management record 201 is generated for each reception, and one
11 to manage the received image data. The items included therein include a mode indicating the attribute of the file (for example, reception, transmission, etc .: this concept is also applied to memory transmission, memory copy, etc.) and page management records 202, 20.
3, 204, and the like.

Next, the page management records 202 and 20
Reference numerals 3 and 204 are generated each time one page is received, and manage one page of received image data in the image memory 109.
The items included therein include a pointer to a page management record of the next page, a mode (for example, an encoding method, a main scanning width, a density in the sub-scanning direction, etc.), a page number, block information, and a line counted at the time of accumulation described above. There are numbers. Then, an end code (NULL) is set in the part of the pointer to the page management record of the last page.

The block information is stored in the image memory 11
A memory block number, which is a serial number when 1 is divided into blocks of a certain size, is managed, and the system control unit 101 can calculate a physical address in the system from the number and the block size. .

The block management table 205 stores the number information of the memory block constituting one page of the received image data in the image memory 111. From the top of this table 205, memory blocks 0, 1, 2
.., Etc., areas are statically allocated to each memory block. Each area stores a pointer to the area of the next block, and an end code (NULL) is set in the area of the last block.
That is, an unused memory block in the image memory 111 can be obtained by searching for a free area from the top of the block management table 205.

Accordingly, to read one page of image data in the image memory 111, the page management record 20
If the first block number is obtained from the block information in 2, 203, and 204 and the pointer is sequentially traced from the area of the corresponding block in the block management table 205, data for one page can be obtained.

Thereafter, when one page of the received image to be printed is accumulated in the image memory 111, the printing process is started in parallel with the above-mentioned receiving process. First, the size of the recording paper attached to the page printer 110 is read via the command / status control unit 117 to obtain the recording paper length.
Further, the number of accumulated lines is obtained from the page management record. Based on such information, it is determined whether or not to perform the division print processing, the reduced print processing, the trailing end line truncation print processing, and the like. Here, assuming that the number of storage lines is N [lines], the recording paper length is M [lines], and the reduction ratio by the reduction unit is R [%], when N ≦ M, printing is performed at 1: 1. N> M,
In the case of N ≦ M × 100 / R, one page is reduced and printed using the reducing means. In the case of N> M × 100 / R, division printing is performed at equal magnification on two or more pages of recording paper.

When the page printer 110 is loaded with a plurality of types of recording paper, the page printer 110 is caused to select one of the plurality of types of recording paper via the command / status control unit 117. During printing, the number of storage lines is N [lines], and the length of each recording paper is M1, M2,.
n [lines] (M1 <M2 <... <Mn) and an allowable reduction ratio is R [%].
1 page is printed at the same magnification. When N> M1 and N ≦ M2, printing is performed on the recording paper M2 at the same size as one page. N ≦ Mn
In the case of × 100 / R and N> Mn, one page is reduced and printed on the recording paper Mn by using the reducing means. N> Mn × 100
In the case of / R, two or more pages are printed on the recording paper Mn at the same magnification.

Here, the number N of image data lines is small recording paper Mi [line] and large recording paper Mi + 1 [line] (Mi <
When the condition of Mi <N <Mi + 1 is satisfied as (Mi + 1), it may be possible to set by an operator's operation whether to perform reduced printing on the small recording paper Mi or equal-size printing on the large recording paper Mi + 1. . Further, a memory for storing the reduction ratio R [%] may be provided in the registration memory unit 115 so that the operator can freely change the value using the console 114.

Reference numeral 301 shown in FIG. 11 is a diagram showing a display example of the operation console unit 114 in this case. Further, a memory for storing whether or not to perform the above-described reduction processing may be provided in the registration memory unit 115 so that the operator can freely change the value using the console 114 (FIG. 1).
302 and 303 shown in FIG. 1).

Further, the reduction ratio by the above-mentioned reduction means is set to Rl
from im [%] (Rlim <100%) to 100%
If a means that can be set in a plurality of stages or linearly is provided and the maximum value of Rlim is automatically selected as the value of R used for reduction determination, optimal reduction printing can be performed according to the recording paper length.

In the trailing edge truncation processing, when the number of storage lines is N [lines], the recording paper length is M [lines], and the trailing edge truncation amount is L [lines], if N ≦ M, all pages are printed on one page. Print the line. If N> M1 and N ≦ M + L, print from the top of the image to N lines on one page,
The remaining printing is not performed. In the case of N> M + L, printing is performed at equal magnification on two or more pages of recording paper. Note that a memory for storing the trailing edge cut-off amount L [line] at this time may be provided in the registration memory unit 115 so that the operator can freely change the value using the console 114. FIG. 11 shows a display example of the operation console unit 114 in this case.
04.

Further, a memory for storing whether or not to perform the above-mentioned trailing end truncation processing may be provided in the registration memory unit 115 so that the operator can freely change the value using the console 114. (305 shown in FIG. 11)
And 306).

In the above-described reduction processing, the main scanning direction and the sub-scanning direction are performed in order to match the cooperation coefficient. However, when the main scanning direction can be printed at the same magnification (for example, A4 data is converted to A4, letter, legal, ), A reduction process in only the sub-scanning direction may be performed.

Hereinafter, the printing process in the third embodiment will be described.

The storage location of the memory image can be determined by following the block management table 205 based on the block information in the page management records 202, 203, and 204 as described above.

First, the code data of the received image stored in the image memory 111 is decoded by the decoding unit 106, and the decoding result is sequentially stored in the line memory unit 104. One line of the stored pixel data is converted into serial data by the parallel-serial converter 107 and sent to the line buffer controller 108. The line buffer control unit 108 stores the data in the line buffer 109. Note that a series of processing (decoding → P / S conversion → storage in the line buffer) is sequentially executed each time the line buffer 109 becomes empty.

On the other hand, in parallel with the above processing, the line buffer control unit 108 stores the data in the line buffer 109 in synchronization with the vertical synchronizing signal SYNC of a fixed cycle requesting the output of one line of print data from the page printer 110. The received image data is sequentially read and output. At this time, the same line is read and output a plurality of times if necessary according to the resolution of the received image. Further, this processing is temporarily stopped when a received image corresponding to the recording paper length recognized in advance by the system control unit 101 at the time of recording is decoded.

The decoding / printing parallel processing may use the interrupt function of the system control unit 101. For example, an interrupt is generated for each value (several msec) shorter than the printing speed of one line.

FIG. 12 is a flowchart showing the parallel processing of decoding / printing using the interrupt function. FIG.
Is a management table format created in order to use each line in the line buffer 109 for parallel processing of decoding / printing, and exists in the RAM of the system control unit 101.

In the decoding unit 401 shown in FIG. 13, the operating state indicates whether the decoding unit 401 is operating (ON) or inactive (OFF). Line # 0, line # 1,..., Line #n indicate what state each line is in. Here, “OFF” is an empty state, that is, a state that may be used for the next decoding process, and “REF” is being used as a reference line in the decoding process (in the case of the MR mode or the MMR mode), COD
"E" is being decoded in the decoding process.

Similarly, in the printing section 402, the operating state means that the printing section 402 is in operation (ON) or in suspension (O
FF). Line # 0, line # 1,..., Line #n indicate what state each line is in. Here, “OFF” indicates an empty state, “ON” indicates a print preparation line, and “PRN” indicates printing.

Reference numeral 403 shown in FIG. 13 denotes a ring queue buffer for controlling the sequentially decoded lines to be printed in order.
The print lines are managed by the print pointer 404, respectively.
Each time one-line decoding is completed, a line number is set and the decoding pointer 405 is incremented. On the other hand, the print pointer 404 fetches the line number from the queue buffer 403, sets a NULL code indicating the meaning of empty each time printing of the line is completed, and increments the pointer. Further, the print pointer 404 cannot pass the decode pointer 405, and the decode pointer 405 cannot start the decoding process of the next line unless the next area is a NULL code.

In the initial state, the operation state of both the decoding unit 401 and the printing unit 402 in the line buffer management table is [O
FF], and the state of each line in the line buffer is also [OF]
F], the ring queue buffer 403 is all filled with NULL codes. And when you start printing,
The operation states of the decoding unit 401 and the printing unit 402 are set to “ON”.

The operation will be described below with reference to the flowchart shown in FIG.

When an interrupt is generated by a timer (not shown), the process proceeds to step S101 to check whether or not the decoding unit is currently decoding. If decoding is being performed, that is, if it is busy, the processing from step S102 to S106 is skipped. However, since the decoding process of the embodiment is sufficiently faster than the interrupt generation interval, it is not skipped by this determination. Here, if decoding is not being performed, the process proceeds to step S102 to search for an empty line buffer. That is, both the decoding unit 401 and the printing unit 402 of the line buffer management table look for a line that is “OFF”. If there is a space, in step S103, there is still a line to be decoded, that is, whether the line for one page of the image memory has been decoded (whether the number of lines stored in the memory has been decoded), or the number of lines corresponding to the recording paper length. Is determined, and if either of the conditions is satisfied, the process proceeds to step S105, where the operation state of the line buffer management table of the decoding unit 401 is set to “OFF” and the decoding unit 401 is set to the sleep state. I do.

However, if this decoding line does not reach either of the two values, the process proceeds to step S104 to acquire an empty line and start the decoding process (issue a start trigger to the decoding processing unit). . At this time, a “CODE” code indicating that decoding is being performed is set in an area of a predetermined line of the line buffer management table of the decoding unit 401. Also, a “REF” code indicating that the area is being used as a reference line is set in the area of the previous decoding line. Then, “OF” is displayed in the area of the previous reference line.
F "is set. In step S106, the previous decoding line is set as a print preparation line. That is, the line number is set in the area of the ring queue buffer 403 indicated by the decoding pointer 405, and the decoding pointer 405 is incremented. At this time, an “ON” code indicating that printing is possible is set in an area of a predetermined line of the line buffer management table of the printing unit 402.

Next, in step S107, the printing unit 40
Check if 2 is currently printing. Here, if printing is in progress, the processing from steps S108 to S111 is skipped. If printing is not being performed, the process proceeds to step S108 to determine whether there is a print preparation line, that is, whether the area of the ring queue buffer 403 indicated by the print pointer 404 is not a "NULL" code. If there is a print preparation line, the process proceeds to step S109, and the printing process of the line is started. At this time, a “PRN” code indicating that printing is being performed is set in an area of a predetermined line of the line buffer management table of the printing unit 402. However, if there is no print preparation line, the process proceeds to step S110, and it is checked whether the decoding unit 401 is paused. If the decoding unit 401 is paused, printing of one page of recording paper is completed. If the printing is not paused, the process proceeds to step S111 to open the printing end line. At this time, an “OFF” code indicating that there is an empty area in a predetermined line area of the line buffer management table of the printing unit 402 is set.

Further, in the case of division printing, it can be realized by repeating the above processing. However, when the compression mode of the image memory is MR or MMR, it must be managed as the last line reference line of the previous page.

Since the operation speed of the page printer 110 as a printing unit is constant, print data must not be lost inside the line buffer 109 during printing of one page of recording paper. Therefore, if the error line is removed at the time of reception as described above, a series of processing “decoding → P / S conversion →
"Storing in line buffer" enables printing to a page printer that prints at a constant speed without having a page buffer.

FIG. 14 is a diagram showing the flow of processing of received image data in the third embodiment. In the figure, 50
1 is a line, 502 is an NCU / modem, 503 is a decoding unit, 504 is a coding unit, 505 is an image memory, 506 is a decoding unit, 506 is a line buffer, and 508 is a laser beam printer.

This control can be applied to a copy operation. First, the data read by the reading unit 102 is S /
The data is converted into parallel data by the P conversion unit 103 and sequentially stored in the line memory unit 104. On the other hand, encoding section 105
Sequentially encodes the read data stored in the line memory unit 104 and stores the encoded data in the image memory unit 111. Thus, all originals are stored in the image memory unit 111.

As in the case of the reception, the image management data storage unit 1
In 16, management information of the copy image is created. The printing operation is the same as the printing process in the receiving operation described above. At this time, after the reading of the original is completed, before the original is printed, when the accumulation line satisfies the conditional expression for performing the reduction processing, a means for notifying the operator of the fact is provided. The setting may be made by the operation of. 3 shown in FIG.
07 is a diagram showing a display example of the operation console unit 114 at this time.

Similarly, when the storage line satisfies the conditional expression for performing the rear end truncation processing, a means for notifying the operator of the fact that the accumulation line satisfies the conditional expression for performing the rear end truncation processing is provided. May be set by an operator's operation. Reference numeral 308 shown in FIG. 11 shows a display example of the operation console unit 114 at this time.

FIG. 15 shows the page printer section 110.
6 is a timing chart showing the operation of FIG. The page printer unit 110 outputs a synchronization signal SYN every time one line is printed.
C is output every T time. Every time this SYNC is received, the line buffer control unit 108 reads out and outputs one line of print data from the line buffer 109 with a delay of a certain time t. Therefore, in the case of the third embodiment, T
The data of the new print line must be stored in the line buffer 109 within the time.

In FIG. 15, the page printer 110
This is an example in which the resolution of the print image is the same as that of the print image. When the resolution of the print image is １ ／, each print line is output twice.

As described above, according to the third embodiment, the received image data is coded and stored in the image memory except for the error line while decoding the received image data, and the factors at that time are counted and stored. When printing the image data of one page, the process of storing the pixel data in the line buffer and the reading of the pixel data from the line buffer to the page printer while decoding the compressed and coded data in the image memory are performed. By executing the printing process in parallel, a low-cost page printer type facsimile apparatus can be realized.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings.

First, the outline of the printing operation of the laser beam printer (LBP) will be described with reference to FIG. The recording paper 607 is conveyed from the paper feed cassette 608 to the position of the registration roller 603 by the paper feed roller 604. On the other hand, an electrophotographic process of charging (by corona discharge or the like), exposure (by laser beam scanning), and development (toner adhesion) is performed on the surface of the photosensitive drum 601.

The laser beam is turned on / off according to a laser drive signal (not shown) generated based on a video signal as image data, and is irradiated onto the photosensitive drum 601 by a polyhedral mirror (not shown) rotating at a constant speed. .
At this time, by rotating the photosensitive drum 601 at a constant speed, the vertical direction (the longitudinal direction of the recording paper) is synchronized with the laser beam scanning.

The registration roller 603 is connected to the photosensitive drum 60.
The recording paper 607 is sent out such that the leading edge of the image formed on the recording paper 1 coincides with the leading edge of the recording paper. Then, the charger 60
5, the image is transferred onto the recording paper, and the fixing roller 602
After fixing, the paper is discharged.

That is, once the printing operation is started, it is necessary to transfer the image line data to the LBP without delay while synchronizing with the line-by-line laser beam scanning.

On the other hand, the facsimile apparatus starts printing after decompressing the compressed image data coming from the line. However, the arrival speed of the image line data is not constant, and the decompression processing speed for each line varies depending on the data, and cannot be directly transferred to the LBP. Therefore, as a means for solving such a problem, a memory (hereinafter, a page buffer) for storing one page of print image data has been provided.

FIG. 17 is a diagram showing signals exchanged between the LBP control unit and the LBP in the facsimile machine. In the figure, a / PRNT signal is a signal that the LBP control unit instructs the LBP to start or continue a printing operation. When this / PRNT signal is asserted (meaning that the signal is valid), the recording paper 607 is fed from the paper feed cassette 608 to the position of the registration roller 603 by the paper feed roller 604. The / VDO signal is a signal representing image data to be printed by the printer. The / BD signal is a main scanning synchronization signal, and indicates that the laser beam is the starting point of the main scanning. The / TOP signal is a sub-scanning synchronization signal. After a certain period of time after receiving the / TOP signal, the LBP control unit synchronizes with the / BD signal and outputs the / VDO signal.
Output a signal.

FIG. 18 is a diagram showing a time relationship between the / VDO signal and the / BD signal. As shown, assuming that the period of the / BD signal is T time, the / VDO signal is output t hours after the / BD signal, and ends within T time.

FIG. 19 shows a time relationship among the / PRNT signal, the / TOP signal, and the / VDO signal. Here, a case where a plurality of pages are continuously printed will be considered.

First, when the LBP control unit asserts the / PRNT signal for printing the Nth page, / T
An OP signal is returned. The LBP control unit negates (means to invalidate) the / PRNT signal, and after a predetermined time,
The / VDO signal is output in synchronization with the / BD signal from the BP. This / PRNT signal must be negated within a certain time (time T2) after the / TOP signal is returned.

This is because the LBP starts the feeding operation of the next page regardless of whether the image data of the next page is ready. Conversely, if the image data for the next page is ready, the maximum printing throughput can be obtained by asserting the / PRNT signal again within a certain time (T1 time) after the / TOP signal returns. Becomes

That is, in the fourth embodiment, when the image data of the next page is prepared, the / PRNT signal for instructing the continuation of printing is asserted during printing, so that the maximum capacity of LBP ( It is an object of the present invention to provide a facsimile apparatus capable of extracting the number of print pages per unit time).

The configuration of the facsimile apparatus according to the fourth embodiment is the same as that of the above-described third embodiment, and a description thereof will be omitted. Further, the process of encoding and storing the received data in the image memory 111 and transferring the data to the line buffer 109 is also a third process.
This is the same as the embodiment, and the data transfer from the line buffer 109 to the LBP will be described below in detail.

First, after the printing process is started, the / PRNT signal is asserted when a predetermined number of lines of pixel data are accumulated in the line buffer 109. After that, a control signal is exchanged with the LBP. This process takes several milliseconds
This is performed by an interrupt function generated every time.

FIG. 20 is a flowchart showing the above-described LBP control interrupt processing. First, after asserting the / PRNT signal, the control variable mode is set to "0" to enable interrupt processing. Here, when an interrupt occurs, the process proceeds to step S1201, and the control variable m
Check the value of mode. As a result, if the value is “0”, the process proceeds to step S1202, where the sub-scanning synchronization signal / TO
It is checked whether P has been received. If P has not been received, the process returns from the interrupt processing. However, if it has been received, the process proceeds to step S1203, where "1" is set in the control variable mode.
The T signal is negated and the routine returns.

If the control variable mode is "1" in the above step S1201, step S12
The process proceeds to 05, and it is checked whether the next page is determined. Here, if it is determined, the process proceeds to step S1206, asserts the / PRNT signal, and proceeds to step S1207.
Then, “2” is set to the control variable mode, and the process proceeds to step S1208.

On the other hand, in the above-mentioned step S1201, the case where the control variable mode is "2" and the step S12
If the next page has not been determined in 05, the process advances to step S1208 to check whether the printing time for one page has elapsed. As a result, if the time has not elapsed, the process returns as it is, but if the time has elapsed, the process returns from the interrupt processing and stops the interrupt. When printing a plurality of pages, the above processing is repeated.

As described above, if the / PRNT signal is asserted within the time T1 shown in FIG. 19 in step S1206, the / TOP signal of the next page is immediately returned in step S1202. The printing ability (the number of printed pages per unit time) will be achieved.

Here, the printing operation of the line buffer control unit 108 will be described with reference to FIG. From the page printer 110, a main scanning synchronization signal / BD is output every T time every time one line is printed. After a lapse of a predetermined time after receiving the / TOP signal, every time the / BD signal is received, the line buffer control unit 108 reads out and outputs one line of print data from the line buffer 109 with a delay of a predetermined time t.

Therefore, in the case of this example, data of a new print line must be stored in the line buffer 109 within the time T. This is an example in which the resolution of the page printer is the same as that of the print image. When the resolution of the print image is １ ／, each print line is output twice. .

Further, as shown in FIG. 22, even after the detection of the / TOP signal, until the next page is prepared, that is,
The / PRNT signal until "the page management record of the page being printed is not an end code but a pointer is linked to the page management record of the next page" and "the page determination code of the page management record of the next page is ON". Is asserted to issue a print continuation instruction to the LBP. If the above condition is not satisfied by the time T2, the / PRNT signal may be temporarily negated.

Here, the above-mentioned T2 time is a time during which the printing operation can be stopped on the page by negating the / PRNT signal within this time after receiving the / TOP signal. / PR after T2 time has passed
If the NT signal is negated, the LBP will start feeding the next page regardless of whether the image data of the next page is ready. If the above condition is satisfied during the subsequent printing, the / PRNT signal is asserted again.

FIG. 23 is a flowchart showing the LBP control interrupt processing in the above-described example. First, in step S1301, the value of the control variable mode is checked, and the process branches depending on the value. If the value is "0", the process advances to step S1302 to check whether the sub-scanning synchronization signal / TOP has been received. If not, the process returns from the interrupt process. However, if received, the process proceeds to step S1303, and the T2 timer is started. Then, in step S1304, "1" is set to the control variable mode, and the routine returns.

If the control variable mode is "1" in step S1301, the process proceeds to step S1305 to check whether the T2 timer has timed out. If the timeout has not occurred, the process returns as it is. If the timeout has occurred, the process proceeds to step S1306 to check whether the next page has been determined. As a result, if it is determined, the process proceeds to step S1312. If it is not determined, the process proceeds to step S1307.
In step S1308, the control signal mode is set to "2", and the process returns.

In step S1301, if the control variable mode is "2", the process advances to step S1310 to check whether the next page is determined. as a result,
If it is determined, the process proceeds to step S1311,
Assert the PRNT signal, and in step S1312,
"3" is set to the control variable mode. On the other hand, if it has not been determined, and if the control variable mode is “3” in step S1301 described above, step S1301 is executed.
The process advances to step 1313 to check whether the printing time for one page has elapsed. Here, if the time has not elapsed, the process returns as it is, but if the time has elapsed, the process returns from the interrupt processing and stops the interrupt.

As described above, according to the fourth embodiment, the LBP
Can be realized in the printing of the received image, and the disadvantage that the LBP printing speed cannot keep up with the arrival speed of the received image can be solved.

[Modification of Fourth Embodiment] In the fourth embodiment,
Although the LBP is used as the page printer, the present invention is not limited to this, and can be applied to, for example, a thermal transfer printer, an inkjet printer, or a thermal printer. Originally, these printers do not need to record one page at a constant speed unlike LBP, but printing quality can be improved by recording one page at a constant speed using this system.

FIG. 24 is a diagram showing an example using an ink jet printer. In the figure, 701 is an ink jet cartridge, 702 is a paper feed roller, 703 is a recording paper, and 704 is a paper feed cassette.

According to the modified example, there is an advantage that the conveyance of the next recording sheet and the preparation of the ink jet (for example, positioning of the ink jet head, etc.) can be performed when printing of the next page is started immediately upon reception.

In the fourth embodiment, the explanation has been given only for the receiving operation. However, the memory copying, that is, the original is read by the scanner and stored in the image memory, and the number of copies designated by the key on the console is printed. It can also be applied to cases. In this case, whether or not the above-described next page is determined is reduced each time the designated number of copies is set in the counter and one page is printed, and if the counter value is not zero, it may be considered that the next page is determined.

Note that the present invention may be applied to a system composed of a plurality of devices or to an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the above is achieved by supplying a program to a system or an apparatus.

[0128]

As described above, according to the present invention,
By performing decoding processing and recording processing in parallel using a plurality of line buffer memories, the cost of the apparatus can be reduced. Normally, every time one line is recorded,
Decodes image data while synchronizing with page printer
In the apparatus for decoding, the decoding unit starts decoding for each line.
Start timing is for each line of the page printer
Time so that it is slightly earlier than the start of
Ming must be designed accurately. In contrast
Thus, according to the present invention, a plurality of line buffer memories are provided.
And one line of decoding is
Faster than the recording time of the
Control for synchronizing with the page printer is necessary.
No need to check if there are free lines in multiple line buffer memories
Simple control to control the execution interruption of compounding depending on
Therefore, the design of the apparatus can be performed very easily.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating a configuration of a facsimile apparatus according to a first embodiment.

FIG. 2 is a data flow showing general printing processing at the time of reception.

FIG. 3 is a data flow showing a printing process at the time of reception in the first embodiment.

FIG. 4 is a diagram for explaining a sub-scanning resolution and the number of times of printing.

FIG. 5 is a timing chart showing decoding and printing operations in the first embodiment.

FIG. 6 is a schematic block diagram illustrating a configuration of a facsimile apparatus according to a second embodiment.

FIG. 7 is a flowchart illustrating an operation of supplying data to a line memory.

FIG. 8 is a flowchart illustrating an operation of printing data in a line memory.

FIG. 9 is a schematic block diagram illustrating a configuration of a facsimile apparatus according to a third embodiment.

FIG. 10 is a diagram illustrating a configuration of management information of an image memory according to a third embodiment.

FIG. 11 is a diagram illustrating a display example of a console unit in the third embodiment.

FIG. 12 is a flowchart illustrating an interrupt process according to the third embodiment.

FIG. 13 is a diagram showing a table for managing parallel processing of decoding and printing.

FIG. 14 is a diagram showing a flow of processing of received image data in the third embodiment.

FIG. 15 is a timing chart showing the operation of the page printer unit.

FIG. 16 is a diagram showing a recording paper transport system inside a printer in a fourth embodiment.

FIG. 17 is a diagram illustrating signal lines for controlling a printer according to a fourth embodiment.

FIG. 18 is a timing chart of image data in the main scanning direction.

FIG. 19 is a timing chart of image data in the sub-scanning direction.

FIG. 20 is a flowchart illustrating an interrupt process according to the fourth embodiment.

FIG. 21 is a timing chart of image data in the main scanning direction.

FIG. 22 is a timing chart of image data in the sub-scanning direction.

FIG. 23 is a flowchart showing an interrupt process in the fourth embodiment.

FIG. 24 is a diagram illustrating a modified example of the printer in the fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 System control part 2 Image memory 3 Decoding part 4 Buffer control part 5 Line buffer 6 Print control part 7 Page printer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuyuki Hirai 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Takeshi Toyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-4-57465 (JP, A) JP-A-4-156766 (JP, A) JP-A-5-244426 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 1/41-1/419

Claims (3)

(57) [Claims] 1. A predetermined value regardless of the content of image data
A decoding unit for decoding one line of encoded image data within a time period , and a page buffer for storing the image data from the decoding unit for a plurality of lines and storing the image data for one page No line buffer memory and the line buffer memory records one line of image data.
The line buffer is not synchronized with the recording timing.
While there is free space in the flash memory, a plurality of
Is decoded continuously image data in, it is no vacant
Lever, interrupt the decoded image data to said decoding means
Control means for controlling the image data read out from the line buffer memory in units of one page. At this time, one line of the image data read out from the line buffer memory is recorded regardless of the content of the image data. An image processing apparatus comprising: a page printer that records for a fixed time and records image data on recording paper at a constant speed without interruption during recording of one page of image data. 2. The image processing apparatus according to claim 1, wherein the page printer is a laser beam printer. 3. The image processing apparatus according to claim 1, further comprising storage means for storing coded image data to be decoded by said decoding means.