JP3574289B2 - Printer and method of adjusting reception buffer size in printer - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printer of a computer system, and more particularly to control of a reception buffer for temporarily storing data received from a host computer.
[0002]
[Prior art]
The printing apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 7-144442 can change the size, that is, the capacity, of the reception buffer according to a user command from a control panel or a host computer.
[0003]
[Problems to be solved by the invention]
However, in the related art, the size of the reception buffer is constant unless changed by the user. Users do not like the hassle of frequently changing the size of the receive buffer. However, the amount of print data from the host computer differs for each job.
[0004]
During processing of a print job, the memory is used for various purposes such as a reception buffer, an image buffer, and a work area. When the memory is used in a well-balanced and highly efficient manner for the plurality of uses in conformity with the job processing situation, the overall printing performance including the throughput and the host release time is the highest. Generally, the reception buffer size may be small for a print job with a small data amount, and it is preferable to secure a large reception buffer for a print job with a large data amount. However, in the related art, it is impractical for the user to set the reception buffer size for each job, and it is impossible to adjust the reception buffer size according to the processing status during the processing of the job. is there.
[0005]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a printer that can automatically and dynamically adjust the size of a reception buffer during processing of a print job.
[0006]
[Means for Solving the Problems]
A printer according to a first aspect of the present invention includes a receiving buffer securing unit that secures a receiving buffer on a memory, an image generating unit that reads received data from a receiving buffer, and generates image data from the read data. Image buffer securing means for securing an image buffer for storing image data in a memory, wherein the image buffer securing means adjusts the size of the image buffer according to the amount of generated image data, and The securing unit adjusts the upper limit of the size of the receiving buffer depending on the size of the image buffer according to the progress of the image data generation process and the printing process. When larger, compared when the size of the image buffer is smaller Te, and smaller the upper limit value of the receiving buffer in the range of less than the upper limit value said smaller, depending on the progress of the generation process and the print process, dynamically adjust the size of the receive buffer. A printer according to a second aspect of the present invention includes a receiving buffer securing unit that secures a receiving buffer in a memory, an image generating unit that reads received data from a receiving buffer, and generates image data from the read data, Image buffer securing means for securing an image buffer on the memory for storing the generated image data, wherein the image buffer securing means adjusts the size of the image buffer according to the amount of generated image data, The receiving buffer securing unit dynamically adjusts the size of the receiving buffer depending on the size of the image buffer according to the progress of the image data generation processing and the printing processing . Using at least two values that can be selected as the upper limit of the size, the image bar The upper limit of the size of the receiving buffer is selected from among the at least two values, depending on the size of the free space of the memory determined depending on the size of the In the range, the size of the reception buffer is dynamically adjusted according to the progress of the generation processing and the printing processing .
[0007]
According to the printer according to the first or second aspect of the present invention, the size of the image buffer is preferentially adjusted according to the amount of image data generated in the printer, and the size of the image buffer depends on the size of the image buffer. Then, the upper limit of the size of the reception buffer is adjusted subordinately. Therefore, in the printer, the free space in the memory changes according to the progress of the image data generation process and the printing process, and the upper limit of the size of the reception buffer varies according to the change in the free space. For example, if the free space is large, the upper limit of the size of the receiving buffer is also large, and if the free space is small, the upper limit of the size of the receiving buffer is small. As described above, the upper limit value of the reception buffer size dynamically changes according to the free space of the memory, and the size of the reception buffer is adjusted within a range equal to or less than the upper limit value, so that the memory use efficiency is always good. is there.
[0008]
In a preferred embodiment, the upper limit value of the reception buffer is switched between large and small depending on whether or not the free space in the memory is sufficiently large. Although this two-stage control is relatively simple, it can be expected that a considerably good result is obtained.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram illustrating a functional configuration of the printer of the present invention.
[0010]
The printer 5 connected to the host computer 1 receives the print data sent from the host computer 1 through the host interface 3. The print data is a stream of commands expressed in a language understood by the printer 5. The received print data is temporarily stored in the reception buffer 7 in the heap memory 13. The memory 13 is used for the work area 9 and the image buffer 11 in addition to the reception buffer 7. In order to secure the reception buffer 7, the work area 9, and the image buffer 11 in the memory 13 and control their sizes, a process called a memory management unit 15 operates.
[0011]
A process called a command interpreting unit 17 reads commands from the receiving buffer 7 in the order of reception, interprets the commands, and finally determines whether or not to dot each pixel of the image to be printed. (Hereinafter referred to as image data). The generated image data is stored in the image buffer 11 in the memory 13. Then, a typical hardware element called a print control unit 19 reads out image data from the image buffer 11 by a DMA method and sends it to the print engine 21. The print engine 21 actually forms an image on a hard copy medium such as paper using a color former. Normally, the print engine 21 fetches a medium at a specific speed to perform printing, and the print control 19 reads image data from the image buffer 11 in synchronization with the speed of the print engine.
[0012]
As is well known, the reception buffer 7 is a memory area for temporarily storing print data received from the host computer 1 until the command interpretation unit 17 reads out the print data. The work area 9 is a memory area for storing information necessary for the command interpreting unit 17 to generate image data from print data, such as a font downloaded from the host computer 1. The image buffer 11 is a memory area for temporarily storing the image data generated by the command interpretation unit 17 until the print control unit 19 reads out the image data. The work area 9 and the image buffer 11 should be reserved with priority over the reception buffer 7. If the work area 9 is not secured, the command interpreter 17 cannot operate.
[0013]
Further, as described above, unless the image buffer 11 is secured to provide image data to the print engine 21 in synchronization with the speed of the print engine 21, the print engine 21 normally executes printing. Because you can't.
[0014]
Therefore, as shown in FIG. 2, the work area 9 and the image buffer 11 are allocated in the heap memory 13 in a required size, and the reception buffer 7 is allocated in the remaining area. The management unit 15 operates. In particular, the required size of the image buffer 11 changes every moment. That is, if the command interpreter 17 newly generates image data, the image buffer 11 needs to be increased by the generated data amount. If the print controller 19 newly reads image data, the read image data is read. The image buffer 11 can be reduced by the data amount. The memory management unit 15 adjusts the size of the image buffer 11 according to the progress of the generation and reading of the image data as described above, and furthermore, makes the reception buffer 9 as large as possible depending on the change in the size of the image buffer 11. The upper limit value of the size of the reception buffer 9 is changed so as to secure the size.
[0015]
If the size of the receiving buffer 9 does not exceed the upper limit, print data from the host computer 1 can be continuously received, and the size of the receiving buffer 9 increases accordingly. When the size of the reception buffer 9 exceeds the upper limit, the memory management unit 15 instructs the host interface 3 to temporarily suspend reception. During the suspension, the print data is read from the reception buffer 9 to the command interpreting unit 17 and no new reception is performed, so that the size of the reception buffer 9 decreases. When the size of the reception buffer 9 falls below the upper limit, reception can be resumed.
[0016]
FIG. 3 is a flowchart showing a procedure for controlling the size of the reception buffer 7 performed by the memory management unit 15. In this procedure, the upper limit of the size of the receiving buffer 9 is controlled in two stages, that is, switching between a small upper limit n1 and a large upper limit n2 as schematically shown in FIG. Here, n is the total capacity of the heap memory 13.
[0017]
The memory management unit 15 first compares the total size b of the image buffer 11 and the work area 9 with a value (n−n2) obtained by subtracting the large upper limit value n2 of the reception buffer size from the total capacity n of the heap memory 13. It is determined whether it is sufficiently small (b << (n-n2)) (step S1). In short, it is determined whether there is enough free space in the memory 13 to secure the size of the reception buffer 7 up to the large upper limit n2.
[0018]
The work area 9 is an area for storing fonts downloaded from the host computer 1 and the like. Once the size is determined, it does not change significantly thereafter, so that the size of the reception buffer 7 can be dynamically adjusted. It does not affect as much as the image buffer 11. Therefore, in the following, for the sake of simplicity, the description will be made assuming that the size of the work area 9 is constant, the size of a portion excluding the work area 9 from the total heap memory 13 is n, and the size of the image buffer 11 is b. Do.
[0019]
If b << (nn-2) in step S1 (YES), it means that the memory 13 has a sufficient free space. In this case, the print data is received from the host computer 1 with a strict limit n2, and the reception buffer size a is increased in accordance with the increase in the amount of received data so that the reception buffer 7 can receive all the received data (S2). . As described above, increasing the reception buffer size a as much as possible and receiving data from the host computer 1 contributes to shortening the release time of the host computer 1.
[0020]
While continuing to receive the print data, it is checked whether or not the reception buffer size a has reached the large upper limit n2 (S3). If a has reached n2 (YES in S3), the host interface 3 is instructed. The reception of data from is temporarily stopped (S4).
[0021]
In parallel with the above operation, the command interpreter 17 reads out the print data from the reception buffer 7, interprets the print data, and creates image data. Therefore, while the data reception is stopped, the amount of print data in the reception buffer 7 decreases as the processing of the command interpreter 17 progresses. Therefore, the receiving buffer size a is also reduced in accordance with this reduction (S5). Conversely, since the amount of image data generated by the command interpreter 17 increases, the size b of the image buffer 11 is increased in accordance with the increase of the data so that all the image data can be stored in the image buffer 11. (S5).
[0022]
If the image buffer size b increases and does not satisfy b << (n−n2) (NO in S1), that is, if the free space of the memory 13 becomes insufficient, the control proceeds to step S6, where the reception buffer size a Is switched to the smaller upper limit n1. That is, first, it is determined whether or not the reception buffer size a is smaller than the small upper limit value n1 (S6). If a is not smaller than n1 (NO in S6), the data reception stop is further continued (S7). As in step 5 already described, the size of the reception buffer 7 is reduced as the data in the reception buffer 7 decreases, and the size of the image buffer 11 is expanded as the generated image data increases (S9). As a result, when the reception buffer 7 has shrunk and falls below n1 (YES in S6), reception from the host computer 1 is started again, and the reception buffer size a is increased again with the increase in the amount of reception data. (S10). When the reception buffer size a exceeds n1 (YES in S11), the reception is stopped again (S12), and the process proceeds to step S9.
[0023]
As described above, while the image data is increased and the free space is not sufficient, the reception and the reception stop are repeated within a range in which the reception buffer size a does not exceed the small upper limit value n1, during which the printing by the print engine 21 starts. When this is done (YES in S8), the control returns to step S1. When printing is started, the image data in the image buffer 11 is transferred to the print control unit 19, so that the data amount in the image buffer 11 decreases, and the image buffer size b also decreases accordingly. As a result, when the image buffer size b is sufficiently smaller than (n-n2) (YES in S1), the control returns to step S2, and the size a of the reception buffer 7 is controlled based on the large upper limit n2. .
[0024]
As described above, depending on the size of the image buffer 11, if the free space is sufficiently large, the receiving buffer 7 should be secured relatively large, and if the free space is not sufficiently large, the receiving buffer 7 should be secured. The reception buffer size is dynamically adjusted so as to ensure that is relatively small.
[0025]
In the above description of the operation, the size of the work area 9 is fixed. However, if the sum of the image buffer size and the work area size is set to b, it is possible to cope with a change in the work area size.
[0026]
FIG. 4 is a schematic diagram showing a specific example of a process in which the size of each buffer is automatically adjusted by the above-described control. The horizontal axis shows the elapsed time, and the vertical axis shows the amount of memory. On the vertical axis, the total width n is the total capacity of the memory 13, n1 is a small upper limit of the receive buffer size, n2 is a large upper limit of the receive buffer size, a is the size of the receive buffer 7, b is the size of the image buffer 11 (or , The total size of the image buffer 11 and the work area 9).
[0027]
First, since little data is stored in the memory 13 at T0 before the start of print data reception, the reception buffer size a is the minimum value a0 and the image buffer size b is also the minimum value b0. When the reception of the print data is started from this initial state, since the free space is sufficient, the reception is performed without limitation, the reception buffer size a increases at a stretch, and the size equal to the large upper limit value n2 at the time T1. reaches a1.
[0028]
Then, the reception stops, so that the reception buffer size a decreases and the image buffer size b increases with the progress of the image generation processing. Then, when the image buffer size b becomes large enough to be equal to (n-n1) as at time T2, the reception is stopped until the reception buffer size a falls below the small upper limit n1. Therefore, as shown at the time T3, the reception buffer size a decreases more and the image buffer size b increases more and more. Then, at time T4, when the reception buffer size a falls below the small upper limit value n1, the reception is started again, and the reception buffer size a increases.
[0029]
Here, for example, when printing is started at the time point Tp, the image data stored in the image buffer 11 rapidly decreases, and the image buffer size b also decreases. As a result, as shown at time T5, when the image buffer size b becomes sufficiently smaller than (n−n2), the reception is restarted and the reception buffer size a is increased. Then, as in time T6, as long as the image buffer size b is sufficiently small, the reception buffer size a is increased to the large upper limit value n2 at a stretch.
[0030]
It should be noted that the process shown in FIG. 4 is an example, and the buffer size does not always change exactly as in FIG. However, those skilled in the art should understand that the control is performed according to the size of the image buffer so that a reception buffer as large as possible can be secured within a range allowed by the free space.
[0031]
In the above description, the upper limit value of the reception buffer size is switched between two levels, but may be adjusted in more steps. That is, the size of the image buffer size b may be divided into multiple levels and determined, and the upper limit value of the reception buffer size may be switched in multiple stages according to the determination result.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a functional configuration of a printer according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram showing an area occupied by each buffer on a heap memory.
FIG. 3 is a flowchart illustrating a procedure of buffer size control according to the embodiment;
FIG. 4 is a schematic diagram illustrating a process of adjusting a buffer size according to the embodiment.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 host computer 3 host interface 5 printer 7 reception buffer 9 work area 11 image buffer 13 heap memory 15 memory management unit 17 command interpretation unit 19 print control unit 21 print engine

Claims (5)

Memory and
Receiving buffer securing means for securing a receiving buffer for storing received data on the memory;
Image generation means for reading received data from a reception buffer and generating image data from the read data;
Image buffer securing means for securing an image buffer for storing the image data generated by the image generating means on the memory,
The image buffer securing means adjusts the size of the image buffer according to the amount of the generated image data,
The reception buffer securing unit adjusts an upper limit value of the size of the reception buffer depending on the size of the image buffer according to the progress of the image data generation processing and the printing processing. When the size of the image buffer is larger, the upper limit value of the reception buffer is made smaller than when the size of the image buffer is smaller, and the generation process and the printing process are performed within a range equal to or less than the reduced upper limit. A printer which dynamically adjusts the size of the reception buffer according to a situation . Memory and
Receiving buffer securing means for securing a receiving buffer for storing received data on the memory;
Image generation means for reading received data from a reception buffer and generating image data from the read data;
Image buffer securing means for securing an image buffer for storing the image data generated by the image generating means on the memory,
The image buffer securing means adjusts the size of the image buffer according to the amount of the generated image data,
The receiving buffer securing means dynamically adjusts the size of the receiving buffer depending on the size of the image buffer according to the progress of image data generation processing and printing processing. Using at least two values that can be selected as the upper limit value of the size, the upper limit value of the size of the reception buffer is set according to the size of the free space of the memory determined depending on the size of the image buffer. Selecting at least one of at least two values, and dynamically adjusting the size of the reception buffer within a range equal to or less than the selected upper limit according to the progress of the generation processing and the printing processing. And the printer. The printer according to claim 1 or 2,
Work area securing means for securing a work area for storing data required for the image generating means on the memory,
A printer according to claim 1, wherein said receiving buffer securing means dynamically adjusts the size of said receiving buffer according to the size of said image buffer and work area. In the receiving buffer size adjusting method in the printer,
Securing a reception buffer for storing received data on a memory in the printer;
Reading received data from a receiving buffer and generating image data from the read data;
Securing an image buffer for storing the image data generated by the generating step on the memory;
A first adjusting step of adjusting the size of the image buffer according to the amount of image data generated by the generating step;
A second adjusting step of adjusting an upper limit value of the size of the reception buffer depending on the size of the image buffer in accordance with the progress of the image data generation process and the printing process , wherein the second adjustment is performed. When the size of the image buffer is larger, the step of reducing the upper limit of the reception buffer is smaller than when the size of the image buffer is smaller, and the generation is performed within a range equal to or smaller than the reduced upper limit. A method of adjusting the size of the reception buffer in a printer , wherein the size of the reception buffer is dynamically adjusted according to the progress of processing and printing processing . In the receiving buffer size adjusting method in the printer,
Securing a reception buffer for storing received data on a memory in the printer;
Reading received data from a receiving buffer and generating image data from the read data;
Securing an image buffer for storing the image data generated by the generating step on the memory;
A first adjusting step of adjusting the size of the image buffer according to the amount of image data generated by the generating step;
A second adjusting step of adjusting the size of the receiving buffer depending on the size of the image buffer according to the progress of the image data generating process and the printing process , wherein the second adjusting step is Using at least two values that can be selected as the upper limit value of the size of the receiving buffer, the upper limit decreases as the free space decreases according to the size of the free space of the memory determined depending on the size of the image buffer. The upper limit value of the size of the reception buffer is selected to be one of the at least two values so that the value becomes a smaller value, and the generation process and the printing process are performed in a range equal to or less than the selected upper limit value . A method for adjusting the size of a receiving buffer in a printer , wherein the size of the receiving buffer is dynamically adjusted according to the progress .

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