JP3978805B2 - Printing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing apparatus that prints print data via a memory.
[0002]
[Prior art]
A facsimile apparatus as an example of a communication apparatus can be connected to a computer such as a personal computer, and decompresses the print data so as to print the print data such as characters and figures which are compressed and transmitted from the computer. However, there are those equipped with a serial type printing device capable of printing on paper. This printing apparatus includes, for example, a CPU that controls the entire apparatus, a decompression unit that decompresses compressed print data, a DMA controller that directly controls transfer of decompressed print data to a memory, and print data for one band. It has a storage area that can be stored, a memory that has a work area for various data processing by the CPU, and a print section that prints print data on paper by driving the print head.
[0003]
In the printing apparatus having such a conventional configuration, the received print data is automatically decompressed by the decompression unit and directly written into the storage area of the memory via the DMA controller, and then the print data is read from the storage area. The printing operation is performed by driving the print head while reading. When the printing operation for one band is completed, the DMA controller directly writes the printing data for the next band in the storage area of the memory, and performs the printing operation for the next band in the same manner as described above.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional printing apparatus, the print data is automatically decompressed by the decompression unit and then directly written into the memory. Therefore, the print data has been altered before decompression due to external factors such as noise during transfer. In this case, if the modified print data is decompressed as it is and directly written in the memory, the print data may be expanded to the work area of the CPU in some cases. There is a problem that an abnormal behavior appears in the processing operation of the CPU to be controlled, and as a result, an abnormal operation may occur in the apparatus.
[0005]
SUMMARY An advantage of some aspects of the invention is that it provides a printing apparatus that can avoid development of print data in a work area of a CPU.
[0006]
[Means for Solving the Problems]
To achieve the above object, a printing apparatus according to a first aspect of the present invention has a storage area for storing print data to be printed on a recording medium, and a memory having a work area for various data processing. And a writing means for writing print data to the memory, a reading means for reading the print data from the memory, and a printing means for printing the print data read by the reading means on the recording medium. an apparatus, said reading means, among the print data to be printed by said printing means, each write is completed to the memory of the print data of a predetermined amount by said writing means, the written The print data is read out before the completion of writing of the print data for the predetermined amount by the writing means. When it is determined to be written to, the predetermined amount of stopping the writing of the print data, without being read by the reading means with respect to the predetermined amount of print data, write stop moving to the next writing process Have means.
[0007]
According to this printing apparatus, before completion of the writing of all the predetermined amount of print data, if the print data is written in the work area of the memory, the writing of the print data of the predetermined amount is stopped, the predetermined amount Since the print data is not read by the reading means and the process proceeds to the next writing process, even if the print data is altered and written in this work area, the development of the print data in the memory is avoided. Therefore, the processing operation of the CPU that performs various data processing in the work area of the memory is not abnormal, and the occurrence of abnormal operation in the apparatus can be prevented.
[0008]
According to a second aspect of the present invention, there is provided a printing apparatus having a storage area for storing print data to be printed on a recording medium, and working for various data processing partitioned by the storage area and partitions. A memory having an area; a writing means for writing print data into the memory; a reading means for reading print data from the memory; and a printing means for printing the print data read by the reading means on the recording medium. a printing apparatus equipped with said reading means, said out of the print data to be printed by the printing means, for each write to the memory of the print data of a predetermined amount by said writing means is completed The written print data is read out, and when the print data is written by the writing means, the write area is stored in the memory. Write area determination means for determining whether the area is a work area or a work area, and before the writing of all the predetermined amount of print data by the write area determination means is completed, When it is determined that the data is to be written into the work area of the memory, writing of the predetermined amount of print data is stopped, and the predetermined amount of print data is not read by the reading unit, and the process proceeds to the next writing process. Writing stop means.
[0009]
According to this printing apparatus, before the completion of writing all the print data for a predetermined amount, it is determined whether or not the print data is written in the work area of the memory based on the partition. Writing of the print data to the memory is stopped, and the predetermined amount of print data is not read by the reading means, and the process proceeds to the next writing process, so that development of the print data in the memory is avoided. Therefore, the CPU does not cause any abnormality in the processing operation of the CPU that performs various data processing in the work area of the memory, and the occurrence of abnormal operation in the apparatus can be prevented.
[0010]
Furthermore, a printing apparatus according to a third aspect is the printing apparatus according to the first or second aspect, wherein the printing data is transferred to the writing means while decompressing the compressed printing data. Has thawing means.
[0011]
According to this printing apparatus, in addition to the effect of the printing apparatus according to claim 1 or 2, since the compressed print data is delivered to the writing means while being decompressed, the decompression result cannot be predicted. Even with such modified print data, development of the print data in the work area is reliably prohibited.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.
[0013]
FIG. 1 is a block diagram of a facsimile apparatus having a printing apparatus according to the present invention. I have. The CPU 1, NCU 2, RAM 3, modem 4, ROM 5, EEPROM 6, gate array 7, codec 8, and interface 9 are connected to each other by a bus line. The bus line includes an address bus, a data bus, and a control signal line. A reading unit 11, a printing unit 12, an operation unit 13, and a display unit 14 are connected to the gate array 7. A telephone line 15 as an example of a communication line is connected to the NCU 2. A personal computer 31 can be connected to the interface 9.
[0014]
The CPU 1 controls the entire facsimile apparatus. The NCU 2 is connected to the telephone line 15 and performs network control. The RAM 3 stores various data and provides a work area for the CPU 1. The modem 4 performs modulation of transmission data, demodulation of reception data, and the like. The ROM 5 stores various programs executed by the CPU 1. The EEPROM 6 stores various data and flags. The gate array 7 functions as an input / output interface for the CPU 1 and performs printing processing and the like. The codec 8 performs encoding of transmission facsimile data. The reading unit 11 takes in read data from a read document. The printing unit 12 prints print data on a recording sheet as a recording medium using a print head or the like. The operation unit 13 includes a group of key switches and the like, and outputs a signal corresponding to a user operation. The display unit 14 includes an LCD and the like, and is controlled by the CPU 21 to perform various displays.
[0015]
FIG. 2 is a block diagram of the print processing unit realized by the gate array 7 in FIG. 1, and the main points of the printing apparatus according to the present invention will be described based on this figure. The RAM 3 is printed by the print head. In addition, there is a storage area for storing print data for one band and a work area as a work area for various data processing by the CPU 1. These areas are assigned addresses for each byte. It is configured to be partitioned by partitions based on pointers.
[0016]
That is, the DMA controller 23 has a pointer composed of a register or the like, generates a write address and a read address for the RAM 3 based on the value of the pointer, and print data writing reaches the final address of the storage area. It is determined whether or not. The initial value of this pointer is set by the CPU 1 and may be the first real address of the storage area, or may be 0 or 1, for example. For example, when four storage areas are set corresponding to four colors of cyan, magenta, yellow, and black for color printing, the initial values are set by the CPU 1 to pointers corresponding to the respective storage areas. The Further, when one storage area is set for monochrome printing, only one pointer is provided. In the following description, the case of monochrome printing will be described in order to facilitate understanding of the contents.
[0017]
When the print data is written, the DMA controller 23 increments the pointer by 1 for every writing of 1 byte, that is, 8 bits. When all the storage areas are used by this writing, the pointer reaches a predetermined value. Therefore, it can be determined that if more writing is performed, the print data is written in the work area. If the print data is correct, all the print data for one band should be able to be written in the storage area, and overflowing from the storage area means that the print data is abnormal. When the predetermined value is reached, the subsequent print data is not written to the RAM 3 for that band. That is, the boundary between the fixed storage area and the work area is a partition.
[0018]
At the time of reading the print data, the DMA controller 23 increments the pointer by a predetermined number for every reading of 1 byte, that is, 8 bits. The predetermined number is determined by the number of pixels in the main scanning direction, that is, the raster direction. For example, when the number of pixels is 1728, the number is 216 bytes, and is incremented by 216. As a result, the print data in the sub-scanning direction of the print head, that is, the print head arrangement direction is read and stored in the register of the print control unit 24. The print head has 64 inkjet nozzles corresponding to black arranged in the sub-scanning direction, and pixels for 64 lines are printed by one main scanning, which corresponds to one band.
[0019]
The CPU 1 manages the address of the RAM 3 based on the program stored in the ROM 5, and calls the program or data stored in the work area while designating the address to the RAM 3 via the DMA controller 23. Various data processing is executed.
[0020]
The gate array 7 is schematically configured as a hard logic circuit having an I / F control unit 21, a data decompression unit 22, a DMA controller 23, and a print control unit 24. The CPU 1 is connected to the internal bus line of the gate array 7.
[0021]
The I / F control unit 21 is connected to the personal computer 31 via the interface 9, and controls transfer of compressed data via the interface 9 to the data decompression unit 22.
[0022]
The data decompression unit 22 transfers the print data compressed in the TIFF format to the DMA controller 23 based on the timing signal while automatically decompressing the print data.
[0023]
The DMA controller 23 writes or reads the print data transferred from the data decompression unit 22 directly to or from the RAM 3, and generates prints for each band while generating addresses assigned to each area of the RAM 3. Write or read data. Further, when writing the print data to the RAM 3, it is determined whether the write area is a storage area or a work area based on the pointer partitioned by the partition, and the print data is written to the work area. If it is determined, the writing is stopped.
[0024]
The print control unit 24 drives and controls the print head of the print unit 12 based on the print data for one band read from the RAM 3 by the DMA controller 23. As a result, print data for one band such as characters and figures is printed on the paper, and the characters and figures are displayed on the entire paper by repeating the printing operation for one band.
[0025]
In other words, the DMA controller 23 realizes a writing area determination means for determining whether a print data writing area is a memory storage area or a work area on the basis of the partition and prints in the work area. When it is determined that the data is to be written, a writing stop means for stopping the writing is realized. The DMA controller 23 also realizes writing means for writing print data to the memory and reading means for reading print data from the memory. The data decompression unit 22 implements a data decompression unit that delivers the print data to the writing unit while decompressing the compressed print data. The print control unit 24 and the print unit 12 realize a printing unit that prints print data on a recording medium.
[0026]
Next, the main points of the operation of the printing apparatus configured as described above will be described with reference to FIG.
[0027]
FIG. 3 is a flowchart showing the printing operation of the printing apparatus according to the present invention. As shown in this figure, first, the compressed print data is sent from the personal computer 31 to the interface 9 and the I / F control unit 21. When transferred to the data decompression unit 22, the data decompression unit 22 transfers the print data to the DMA controller 23 while decompressing the print data by decompression based on the compression format (S1).
[0028]
When the print data is transferred, the DMA controller 23 generates a write address for designating a write area of the RAM 3 based on the pointer (S2).
[0029]
Further, the DMA controller 23 determines whether or not the write address generated by the DMA controller 23 exists in the storage address assigned to the storage area of the RAM 3 based on the pointer (S3).
[0030]
When the write address exists in the storage address (S3: YES), the DMA controller 23 writes the print data in the storage area specified by the write address (S4).
[0031]
Through such processing, when the CPU 1 determines that writing of print data for one band has been completed by a command from the DMA controller 23 (S5: YES), it sends a read request signal to the DMA controller 23, The DMA controller 23 sequentially reads the print data for one band from the storage area of the RAM 3 based on the timing signal (S6).
[0032]
The print control unit 24 drives the print head based on the sequentially read print data, whereby the print data for one band is printed while the print head moves in the main scanning direction with respect to the paper (S7). .
[0033]
When the printing operation for one band is completed, the CPU 1 determines whether or not the DMA controller 23 waits for writing of print data for the next band (S8). If there is no print data waiting for writing (S8: YES), the main routine of this printing process is terminated.
[0034]
In S8, when the DMA controller 23 waits to write the print data for the next band (S8: NO), the process returns to S2 and continues.
[0035]
If the writing of print data for one band has not been completed in S5 (S5: NO), the process returns to S2 and continues.
[0036]
In S3, if the write address generated by the DMA controller 23 does not exist in the storage address and is an address designating the work area of the RAM 3 provided as the work area of the CPU 1 (S3: NO), the next S4 In step S9, writing of print data to the RAM 3 by the DMA controller 23 to be executed is stopped (S9). After the writing is stopped, the process returns to step S2 to continue the process. That is, the overflowed print data is not written in the RAM 3.
[0037]
Therefore, according to such a printing apparatus, external data such as noise is added to the print data before decompression from the interface 9, and modified data that cannot predict how the data will be developed in the RAM 3. Even if it becomes, since the data writing to the work area assigned to the RAM 3 is avoided, there is no abnormality in the processing operation of the CPU 1 or the like that performs various data processing in the work area. Generation of operation can be prevented.
[0038]
Even when some print data is about to be written to the work area of the CPU 1, other print data is normally written to the storage area without being developed in the work area. Based on the print data normally written in the storage area, the print operation can be continued without stopping.
[0039]
In this embodiment, the print data is compressed in the TIFF format. However, the print data is not particularly limited, and may be compressed in the JPEG or GIF format.
[0040]
In the above embodiment, the case of monochrome printing has been described. However, the same applies to color printing, and it may be determined whether or not the partition is exceeded by a storage area pointer adjacent to the work area.
[0041]
In the above embodiment, the partition is set and the storage area and the work area are fixed, but the boundary between the storage area and the work area may be set flexibly by the CPU 1.
[0042]
【The invention's effect】
As described above, according to the printing apparatus of the first aspect of the present invention, when the print data is written in the work area of the memory before the writing of all the print data for the predetermined amount is completed, the predetermined amount. The writing of the print data is stopped, and the predetermined amount of print data is not read by the reading means, and the process proceeds to the next writing process. Therefore, the print data may be altered and written to this work area. However, since the expansion of the print data into the memory is avoided, the processing operation of the CPU that performs various data processing in the work area of the memory is not affected, and the occurrence of the abnormal operation in the apparatus is prevented. Can do.
[0043]
According to the printing apparatus of the second aspect of the present invention, it is determined on the basis of the partition whether or not the print data is written in the work area of the memory before the completion of writing the print data for a predetermined amount. When writing to the work area, the writing of the print data to the memory is stopped, and the predetermined amount of print data is not read by the reading means, and the process proceeds to the next writing process. Since development to the memory is avoided, it is possible to prevent abnormal operation in the apparatus without causing any abnormality in the processing operation of the CPU that performs various data processing in the work area of the memory.
[0044]
Furthermore, according to the printing apparatus of the invention described in claim 3, in addition to the effect of the printing apparatus described in claim 1 or 2, the compressed print data is delivered to the writing means while being decompressed. Therefore, even if the print data has been modified so that the decompression result cannot be predicted, the development of the print data in the work area is surely prohibited.
[Brief description of the drawings]
FIG. 1 is a block diagram of a facsimile apparatus including a printing apparatus according to the present invention.
FIG. 2 is a block diagram of a print processing unit provided in the facsimile apparatus shown in FIG.
FIG. 3 is a flowchart showing a printing operation of the printing apparatus according to the present invention.
[Explanation of symbols]
1 CPU
3 RAM
5 ROM
7 Gate array 16 Print processing unit 22 Data decompression unit 23 DMA controller

Claims (3)

A memory having a storage area for storing print data to be printed on the recording medium, and a work area for various data processing;
Writing means for writing print data into the memory;
Reading means for reading print data from the memory;
A printing apparatus comprising printing means for printing the print data read by the reading means on the recording medium,
The reading unit, of the print data to be printed by said printing means, each write is completed to the memory of the print data of a predetermined amount by said writing means, reading the written print data Is configured to issue,
If it is determined by the writing means that the print data is written to the working area of the memory before the completion of writing the print data for the predetermined amount, the writing of the predetermined amount of print data is stopped, A printing apparatus comprising: a writing stop unit that shifts to the next writing process without reading the predetermined amount of print data by the reading unit . A memory having a storage area for storing print data to be printed on a recording medium, and a work area for various data processing partitioned by the storage area and partitions;
Writing means for writing print data into the memory;
Reading means for reading print data from the memory;
A printing apparatus comprising printing means for printing the print data read by the reading means on the recording medium,
The reading unit, of the print data to be printed by said printing means, each write is completed to the memory of the print data of a predetermined amount by said writing means, reading the written print data Is configured to issue,
Writing area determination means for determining, based on the partition, whether the writing area is a storage area of the memory or a work area when print data is written by the writing means;
Before the writing area the predetermined amount completion of writing all the print data by determining means, when the print data is determined to be written in the work area of the memory, to stop the writing of the predetermined amount, the A printing apparatus comprising: a writing stop unit that shifts to a next writing process without reading a predetermined amount of print data by the reading unit .   The printing apparatus according to claim 1, further comprising a data decompressing unit that delivers the print data to the writing unit while decompressing the compressed print data.

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