JP3562181B2 - Printer memory management method and memory management device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for managing a memory in a printer such as an inkjet printer.
[0002]
[Prior art]
2. Description of the Related Art In a serial printer such as an ink jet printer, image data necessary for final printing is developed in an image memory by interpreting print data received from a host computer. For example, the print mode includes a character mode for printing characters and a raster mode for printing an image, and image data is developed in an image memory according to each print mode. That is, image data to be printed and output are stored in a plurality of image buffers defined in the image memory, and serial printing is executed by sequentially transmitting the image data in each of the image buffers to the print head. You.
[0003]
Here, for example, a reception buffer memory for receiving print data from a host computer, a development buffer memory for developing final image data, a variable memory for storing various variables, and the like, for each data type to be stored. However, if separate memories are used, the structure becomes complicated and the manufacturing cost increases.
[0004]
Therefore, usually, as shown in FIG. 9, areas for storing various data are set in a memory 500 such as a RAM. Specifically, a BIOS (Basic Input / Output System) use area 510 is used as a reception buffer for temporarily storing print data and is used on the printer system. The common use area 520 is a use area for storing data and variables used in both the character mode and the raster mode. The character mode unique use area 530 includes, for example, a line buffer used for expanding one line of image data, a download area for storing data such as ANK characters downloaded from a host computer, and a character generation area for generating a character image. This is a use area used as a work area or the like. The image area 540 is a use area for developing final image data, and defines a plurality of image buffers 541 to 547. Then, also in the raster mode for printing the raster image data, the image data is developed in the image buffers 541 to 547 in the image area 540.
[0005]
[Problems to be solved by the invention]
In the related art, a BIOS use area 510, a common use area 520, a character mode unique use area 530, and an image area 540 are set on the memory 500 to store various data necessary for printing. Are formed by fixedly assigning addresses of the memory 500 in advance. Also, the set number of image buffers formed in the image area 540 is a predetermined fixed value. Therefore, in the related art, in both the character mode and the raster mode, the image data is developed using the same set number of image buffers 541 to 547 having the same buffer capacity.
[0006]
If the use area of the memory 500 is fixed in advance as in the prior art, the start addresses of the areas 510 to 540 are fixed, so that the data input / output program and the like can be easily performed using these fixed addresses. Can be created. However, if the used area of the memory 500 is fixed, not only does the use efficiency of the memory 500 decrease, but it is not possible to improve the throughput of print output.
[0007]
That is, for example, the character mode unique use area 530 is an area used exclusively in the character mode, and is not used in the raster mode for printing raster image data. Therefore, in the raster mode, the character mode specific use area 530 wastes memory resources and does not contribute to printing at all.
[0008]
Further, since the print head reads out the image data stored in each of the image buffers 541 to 547 and executes printing, the throughput of the print output depends on the set number of the image buffers. On the other hand, since the buffer capacity of the image buffer required for printing differs depending on the print mode and the print resolution, the number of image buffer settings that can be set in the image area 540 also differs. However, in the related art, there is a problem that the print output throughput cannot be improved because the set number of available image buffers is constant regardless of the print mode or the like.
[0009]
The present invention has been made in view of the above-described problems, and has as its object to provide a memory management method and a memory management device for a printer capable of efficiently using the memory of the printer and improving the throughput of print output. Is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, the use area of the memory is dynamically controlled according to the print mode. That is, the memory management method for a printer according to the present invention executes, at least in this order, an analysis step of analyzing print information based on print data and an area allocation step of allocating a use area of the memory based on print information. It is characterized by doing.
[0011]
The print information is a concept including, for example, a printing mode such as character printing or raster image printing, a printing resolution, and the like. By allocating the use area of the memory based on the analyzed print information, it is possible to provide an optimum memory space for the print without securing a use area unnecessary for the print on the memory.
[0012]
Also, Book According to the invention, the analyzing step analyzes the print mode and the resolution as print information, and the area allocating step sets a use area of the memory based on the print mode and sets an image buffer in the use area based on the resolution. Is set.
[0013]
Thereby, the used area of the memory can be dynamically allocated based on the print mode, and the image buffer is set based on the resolution, so that the image buffer can be formed to the maximum within the capacity of the used area. . That is, for example, 360 × 360 DPI and 720 × 720 DPI, the required buffer capacity of the image buffer differs depending on the printing resolution. However, since the image buffer can be set with the required buffer capacity for printing, Thus, the set number of image buffers can be dynamically controlled.
[0014]
Also, Preferred embodiment Then, the analyzing step includes a print mode determining step of determining whether the mode is a character mode for printing character data or a raster mode for printing raster image data based on print mode information in the print data; and And a resolution determining step of determining a printing resolution based on the resolution information of the character mode. The area allocating step includes, when it is determined that the character mode is set, a use area unique to the character mode and image data. An image area to be used for development is set as a use area in the memory. On the other hand, when it is determined that the raster mode is set, a use area setting for setting an image area to be used for image data development as the use area in the memory. A step according to the resolution in the image area. It is characterized by comprising a image buffer setting step of setting an image buffer having a fan capacity.
[0015]
The area to be created on the memory differs between the character mode for printing character data and the raster mode for printing raster image data. Therefore, in the character mode, an image area and a use area specific to the character mode, such as a work area for font development and a line buffer, are set. In the raster mode, an image area is set. Thereby, the memory can be used efficiently according to the print mode.
[0016]
Claim 3 In the use area setting step, the use area unique to the character mode and the image area used for developing the image data can be respectively set as the use areas in the memory in the initial state.
[0017]
That is, by setting the memory area setting for the character mode as the initial setting value, printing in the character mode with a high print frequency can be executed quickly without determining the print mode.
[0018]
Claims 4 Preferably, in the area allocation step, the use area is set in a variable address area in the memory. As a result, a used area can be secured based on the required memory amount.
[0019]
Specifically, the claims 5 The memory is partitioned into a plurality of blocks in advance, and a memory management unit for managing addresses and block use states of the respective blocks is provided, and the area allocation step is performed by the memory management unit. It is preferable to set the use area in units of the blocks to be used.
[0020]
For example, the memory is divided into a large number of blocks in a predetermined byte unit, and the address of each block and the use state of each block are managed by the memory management unit. Here, the “block use state” means whether or not a block is used, what a series of blocks are used for (for example, for image development), and the like. Therefore, in the area allocation step, when setting the used area, the memory management means is inquired about the presence or absence of a series of vacant blocks, and a response from the memory management means (address of a series of free blocks, permission of use of each block) Etc.) and set the necessary use area.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a block diagram of a serial printer to which the present invention is applied. The serial printer generally includes a printer controller 1 and a print engine 2. The printer controller 1 stores an interface (hereinafter referred to as “I / F”) 4 for receiving print data and the like from the host computer 3, a RAM 5 for storing print data and the like and providing a work area, and various control programs and the like. ROM 6, a control unit 7 for executing various data processing and the like in accordance with programs stored in the ROM 6, and an I / F 8 for performing communication between the printer controller 1 and the print engine 2. , 8, RAM 5, ROM 6, and control unit 7 are connected to each other via a bus 9.
[0022]
On the other hand, the print engine 2 includes a print head 10, a carriage mechanism 11, and a paper feed mechanism 12. The print head 10 has, for example, 64 or 128 nozzles arranged in a row in the sub-scanning direction (paper feed direction), and is configured as a serial print head. Then, ink droplets are ejected from each nozzle according to image data by an ink droplet ejection mechanism such as a piezoelectric vibrator or a heating element provided for each nozzle, and the ink droplets are ejected onto recording paper as a print storage medium. Printing is performed by landing and attaching. The carriage mechanism 11 includes a carriage on which the print head 10 is mounted, and a drive mechanism such as a carriage motor for driving the carriage, and drives the print head 10 in a main scanning direction orthogonal to the sub-scanning direction. . The paper feed mechanism 12 includes a paper feed roller and a drive mechanism such as a paper feed motor for driving the roller, and moves the recording paper at a predetermined pitch.
[0023]
FIG. 2 is a functional block diagram showing internal functions of the printer controller 1. First, the print data transmitted from the host computer 3 is stored in the reception buffer 20. The reception buffer 20 is formed in a predetermined area of the RAM 5 as a “memory” as described later. However, in FIG. 2, for convenience of explanation, the reception buffer 20 and the RAM 5 are illustrated separately. I have.
[0024]
The print data stored in the reception buffer 20 is analyzed by the analysis unit 21 as a print mode and print resolution as “print information”. The analysis unit 21 is mainly embodied by the control unit 7 and includes therein a print mode determination unit 22 for determining a print mode and a resolution determination unit 23 for determining a print resolution.
[0025]
Here, the print mode includes a raster mode for printing raster image data and a character mode for printing character data. As shown in FIG. 3, the structure of the print data differs depending on each print mode. In the case of the raster mode, the header information includes data type information RD1, compression mode information RD2, resolution information RD3, and raster height information RD4 as "print mode information", and is followed by raster data RD5. It becomes. Here, the data type information RD1 is indicated by a different control code for each type of print data, for example, “ESC ·”. The compression mode information RD2 is indicated by 2-bit data indicating a compression method. The resolution information RD3 includes a vertical print resolution and a horizontal print resolution, for example, 180 × 180 DPI, 360 × 360 DPI, and 720 × 720 DPI. The raster height information RD4 indicates the height of the raster, that is, how many dot lines of raster data. On the other hand, in the character mode, the data type information CD1 and the attribute information CD2 are added to the character data CD3 as header information. The attribute information CD2 is information indicating an attribute of a character, such as double-width characters and italics.
[0026]
Therefore, the analysis unit 21 can analyze the print mode and the print resolution based on the header information of the print data. Specifically, the print mode determination unit 22 determines whether the print mode is the raster mode or the character mode based on the data type information RD1 or CD1. This print mode determination result is output to the use area setting unit 32 described later. The resolution determination unit 22 determines a print resolution based on the resolution information RD3. Here, in the present embodiment, the print resolution in the character mode is fixed to, for example, 360 × 360 DPI. Therefore, when the character mode is determined, the print resolution is determined to be the fixed value. .
[0027]
The area allocation control unit 31 controls each use area set in the RAM 5 according to the analysis result of the analysis unit 21, and is embodied by the control unit 7. The area allocation control unit 31 includes a use area setting unit 32 and an image buffer setting unit 32. As will be described later, the use area setting unit 32 sets a use area such as an image area in the RAM 5 according to the print mode. Further, the image buffer setting unit 33 sets a plurality of image buffers in the image area according to the print resolution. Note that the image buffer can be expressed as a “print unit image data storage area”.
[0028]
The RAM 5 is roughly divided into a fixed address area 40 in which addresses are fixed and a variable address area 50 in which addresses can be changed. In the fixed address area 40, a BIOS use area 41 and a common use area 42 are fixed. Is set to As described in the related art, the BIOS use area 41 includes, for example, an area used on the system and the reception buffer 20, and the common use area 42 stores variables commonly used in both the character mode and the raster mode. This is an area to store. In the variable address area 50, a character mode unique use area 51 and an image area 52 are set according to the print mode.
[0029]
That is, as shown in FIG. 4, in the case of the character mode, a character mode unique use area 51 and an image area 52 are set. The character mode unique use area 51 includes, for example, a line buffer used for expanding one line of image data, a download area for storing data such as ANK characters downloaded from a host computer, and a character generation area for generating a character image. It is used as a work area or the like. The image area 52 is an area in which image data required for final printing is developed, and a plurality of image buffers 61 are set. Here, each image buffer 61 is set so as to obtain a memory height corresponding to the number of nozzles such as 128 bits and a memory width of 80 digits at a printing resolution of, for example, 360 × 360 DPI.
[0030]
On the other hand, in the case of the raster mode, an image area 53 is set in the variable address area 50. In other words, the image area 52 in the character mode is extended to the character mode specific use area 51. In the case of the raster mode, each image buffer 61 is set in the enlarged image area 53 with a buffer capacity corresponding to each print resolution. That is, as shown in the explanatory diagram of FIG. 7, the buffer capacity required for the image buffer 61 is different depending on the printing resolution of 180 × 180 DPI, 360 × 360 DPI, and 720 × 720 DPI, and therefore, it is possible to form the Also, the set number of the image buffers 61 is different. In the present embodiment, the image buffer 61 is set to the maximum extent in the image area 53 by the image buffer setting unit 33.
[0031]
The image processing section 70 performs necessary processing on the raster data RD5 and the character data CD3 in the print data to create image data, and stores the image data in the image areas 52 and 53 set in the RAM 5. . The image processing unit 70 is embodied by the control unit 7. For example, in the case of character data, the image processing unit 70 generates a character image based on a character code, performs necessary decoration processing, and writes the image in the image area 52. .
[0032]
Next, the operation of the present embodiment will be described. FIG. 5 is a flowchart showing the setting process of the used area and the image buffer setting process according to the present embodiment.
[0033]
First, this setting process is started when the power is turned on. In step (hereinafter abbreviated as “S”) 1, a character mode use area is set in the RAM 5 without determining the print mode. That is, since the character mode is set as the default value of the printer, character printing with a high printing frequency can be started quickly.
[0034]
In S2, the print data is read from the reception buffer 20, and by analyzing the print data, it is determined whether or not the mode has shifted to the raster mode. In the case of the character mode, since the use area setting for the character mode has already been set in S1, the character printing is performed by expanding the character data into image data and reading out each image buffer 61 in order in S3.
[0035]
On the other hand, if the mode has shifted to the raster mode, "NO" is determined in S2, and the process proceeds to S4, where the use area set for the character mode in S1 is released. As described above, since three types of print resolutions are prepared in the raster mode, there is a possibility that the print resolution has been changed by shifting to the raster mode. Therefore, in S5, it is determined whether or not the print resolution has been changed based on the resolution information RD3. If there is no change in the print resolution, that is, if the print resolution matches the print resolution in the character mode, “NO” is determined in S5, and the flow shifts to S8 described below to print the raster image. On the other hand, when a change occurs in the print resolution, the used area is released in S6, and in S7, the image buffer 61 is set to the maximum with a buffer capacity corresponding to the new print resolution. Then, in S8, the image data expanded and stored in the image buffer 61 is read out and the raster image is printed, and in S9, it is determined whether or not the mode has shifted to the character mode. If the mode has not been shifted to the character mode, that is, if printing in the raster mode is continued, “NO” is determined in S9, and the process returns to S5 to determine a change in print resolution. Therefore, even when a raster image having a different printing resolution is printed, a change in the printing resolution is determined in S5 and the used area is released in S6, so that the image buffer 61 is always buffered with a buffer capacity corresponding to the printing resolution. Can be set to the maximum.
[0036]
When the mode is shifted to the character mode, "YES" is determined in S9, and the process proceeds to S10. In S10, the used area is released and the process returns to S1. Thus, in S1, a character-mode use area (character-mode specific use area 51 and image area 52) is set in the RAM 5.
[0037]
According to the present embodiment configured as described above, the use areas 51, 52, and 53 for the RAM 5 can be set based on the print mode, and the image buffer 61 can be set based on the print resolution. As shown in (5), the RAM 5 can be used efficiently according to each print mode. That is, in the raster mode for printing raster image data, the character mode unique use area 51 can be released to set a large capacity image area 53, so that the use area of the RAM 5 is dynamically controlled according to the print mode. And the available memory resources can be increased without performing additional memory or the like.
[0038]
Further, since the image buffer 61 can be set to the maximum in the image area 53 with a buffer capacity corresponding to the print resolution, the number of image buffers 61 set can be dynamically controlled according to the print resolution. The print output throughput can be improved. That is, in the related art, even when the required buffer capacity differs due to the difference in print resolution, the number of image buffers to be set is fixed, so that it is impossible to improve the throughput of print output. The image buffer 61 can be set to the maximum with the required buffer capacity. Therefore, especially when the print resolution is low, the number of image buffers to be set can be increased to improve the throughput of print output.
[0039]
Next, a preferred specific mode of memory management will be described with reference to FIG. FIG. 8 is a conceptual diagram of the printer system. The control structure of the printer system includes a main module 70, a BIOS 71, and an OS (operating system) 72, which are hierarchized. The main module 70 is a main part of the print control program. The BIOS 71 is an interface between the main module 70, which is printer software, and printer hardware (such as the printer engine 2).
[0040]
The OS 72 corresponds to “memory management means”, and performs task management and memory management of the RAM 5. The task management is for managing each processing unit (task) executed at the time of printing. For example, a task of writing print data to the reception buffer 20, a task of expanding print data into intermediate code, a task of creating image data from intermediate code, a task of outputting image data to the print engine 2, and the like. Tasks are set for each process. Priorities are assigned to these tasks in advance. For example, a task of outputting image data to the print engine 2 is given priority over the use of the CPU. Upon completion of its own processing, each task relinquishes the right to use the CPU. As a result, another task obtains the right to use the CPU and executes its own process. When a CPU use request is issued from a task with a higher priority, that request is given priority. As a result, a multitask type printer controller 1 can be obtained.
[0041]
On the other hand, the OS 72 performs memory management of the RAM 5. The RAM 5 is divided into a large number of blocks 73 in predetermined byte units, for example. The OS 72 manages the addresses of all the blocks 72 and the block use state. The block use state is the address of a free block, the presence or absence of a series of free blocks, the type of data written in the block being used, and the like.
[0042]
The main module 70 returns the unnecessary block 72 to the OS 72 according to the print mode of the raster mode or the character mode, and requests the OS 72 to use a new empty block if necessary. . That is, the use areas 51, 52, and 53 described above are configured in units of blocks 72, and the OS 72 centrally manages addresses and the like of the blocks that configure the use areas 51, 52, and 53. It is. Therefore, the start addresses of the use areas 51, 52, 53 can be easily changed.
[0043]
It should be noted that those skilled in the art can make various additions, changes, and the like within the scope of the present invention without being limited to the above-described embodiment. For example, all or a part of the above-described use area setting processing and image buffer setting processing may be stored in the storage medium MM illustrated in FIG. 1, and the content of the storage medium MM may be executed by the control unit 7. It is. The storage medium MM is not limited to a tangible medium such as a CD-ROM, an FD, a ROM, and an IC card, but also includes a communication medium such as a download from a server via a network.
[0044]
In the above embodiment, the single RAM 5 is exemplified as the memory. However, the present invention is not limited to this, and can be applied to a case where an image area is set using a plurality of RAMs.
[0045]
Further, in the above-described embodiment, the case where the present invention is applied to an ink jet printer has been described as an example. However, the present invention can be applied to other serial printers and line printers such as a thermal printer.
[0046]
【The invention's effect】
As described above, according to the memory management method and the memory management device for a printer according to the present invention, the use area of the memory can be dynamically set based on the print information, so that the memory can be used efficiently. Can be. Further, since the image buffer can be dynamically set with a buffer capacity corresponding to the print resolution, the throughput of print output can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram of a serial printer to which an embodiment of the present invention is applied.
FIG. 2 is a functional block diagram illustrating functions in a printer controller.
FIG. 3 is an explanatory diagram showing a structure of print data.
FIG. 4 is an explanatory diagram showing a use area and the like set in a memory;
FIG. 5 is a flowchart showing a use area setting process and an image buffer setting process.
FIG. 6 is an explanatory diagram showing a comparison between states in which a use area set in a memory differs between a character mode and a raster mode.
FIG. 7 is an explanatory diagram illustrating a state in which the buffer capacity and the set number of the image buffer are different depending on the print resolution.
FIG. 8 is a conceptual diagram of a control system of a printer controller.
FIG. 9 is an explanatory diagram showing a use area allocation of a memory according to a conventional technique.
[Explanation of symbols]
1 Printer controller
2 Print engine
3 host computer
5 RAM
7 control section
20 Receive buffer
21 Analysis unit
22 Print mode determination unit
23 Resolution judgment unit
31 area allocation control unit
32 Usage area setting section
33 Image buffer setting section
40 Fixed address area
41 BIOS usage area
42 Common use area
50 Variable address area
51 Character mode unique use area
52 Image area (character mode)
53 Image area (raster mode)
61 Image Buffer
70 Main Module
71 BIOS
72 OS
73 blocks

Claims (8)

Managing the use area of a memory having a reception buffer area for receiving input print data and a use area where print data received in the reception buffer area is expanded into image data printable by a print head. A memory management method for a printer,
An analyzing step of analyzing print information based on the print data,
And a region allocation step of allocating the used area of the memory based on the print information,
The analyzing step includes a print mode determining step of determining whether the character mode to print character data or the raster mode to print raster image data based on print mode information in the print data,
In the area assigning step, when it is determined that the character mode is set, while setting a unique use area unique to the character mode and an image area used for developing image data as the use area in the memory, When it is determined that the raster mode is set, a use area setting step of setting an image area used for developing image data as the use area in the memory without setting the unique use area is provided . Printer memory management method. The analyzing step further includes a resolution determining step of determining a printing resolution based on resolution information in the print data,
Said area allocation step further, the memory management of the printer according to claim 1, characterized in that it comprises an image buffer setting step of setting an image buffer having the resolution buffer capacity according to the image area Method. The use area setting step, according to claim 1, as an initial state, and sets respectively the image region in the memory as the use area to be used for development of the image data with a unique specific use area to the character mode 3. The memory management method for a printer according to claim 1. It said area allocation step, the memory management method of the printer according to any one of claims 2 to 3, characterized in that setting the use area to change the address area in the memory. The memory is partitioned into a plurality of blocks in advance, and a memory management unit that manages an address of each block and a block use state is provided.
It said area allocation step, said by the block unit to be managed by the memory management unit, a memory management method of the printer according to any one of claims 2-3, characterized in that setting the use area. Managing the use area of a memory having a reception buffer area for receiving input print data and a use area where print data received in the reception buffer area is expanded into image data printable by a print head. A memory management device for the printer,
Analysis means for analyzing print information based on the print data,
Bei example a region allocation control means for allocating the used area of the memory based on the print information,
The analysis unit includes a print mode determination unit that determines whether a character mode for printing character data or a raster mode for printing raster image data based on print mode information in the print data,
The area allocation control means sets, in the memory, a unique use area unique to the character mode and an image area used for developing image data as the use area when the character mode is determined. A use area setting unit configured to set an image area used for developing image data in the memory as the use area without setting the unique use area when it is determined that the raster mode is set. The printer's memory management device. The analysis unit further includes a resolution determination unit that determines a print resolution based on resolution information in the print data, and the area allocation control unit further includes, in the image area, 7. The memory management device for a printer according to claim 6 , further comprising image buffer setting means for setting an image buffer having a buffer capacity. The memory is divided into a plurality of blocks in advance, and a memory management unit that manages an address of each block and a block use state is provided, and the area allocation control unit is configured to manage the block by the block unit managed by the memory management unit. 8. The memory management device for a printer according to claim 7 , wherein a use area is set.

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