JPH10254659A - Printer and operation method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer capable of dynamically and automatically adjusting the size of a reception buffer during the processing of a printing job. SOLUTION: Printing data from a host computer 1 are received in the reception buffer 7. When the free capacity of a memory 13 is sufficiently large, the reception buffer 7 is increased to a large size and data reception is accelerated. When a command interpretation part 17 reads the data from the reception buffer 1 and generates image data, an image buffer 11 is increased. When the free capacity becomes insufficient as a result, the data reception is restrained and a reception buffer size is reduced to a small size. When a printing control part 19 reads the image data from the image buffer 11 and starts printing, the size of the image buffer 11 is reduced. When the free capacity becomes sufficient as a result, the reception buffer 7 is enlarged to the large size again and the data reception is accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer for a computer system, and more particularly to control of a reception buffer for temporarily storing data received from a host computer.

[0002]

2. Description of the Related Art The printing apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 7-144442 can change the size, that is, the capacity of a receiving buffer according to a user command from a control panel or a host computer.

[0003]

However, in the prior art, the size of the receiving 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.

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 receiving buffer size for each individual job, and it is impossible to adjust the receiving buffer size according to the processing status during the processing of the job. is there.

It is an object of the present invention to provide a printer which can automatically and dynamically adjust the size of a receiving buffer during the processing of a print job.

[0006]

A printer according to the present invention comprises a receiving buffer securing means for securing a receiving buffer on a memory, an image generating means for reading received data from the receiving buffer and generating image data from the read data. Image buffer securing means for securing an image buffer for storing generated 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. Then, the receiving buffer securing means adjusts the size of the receiving buffer depending on the size of the image buffer.

According to the printer 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 receiving buffer is controlled depending on the size of the image buffer. Is adjusted in a dependent manner. Therefore, in the printer, according to the progress of the image data generation processing and the printing processing,
Although the free space in the memory changes, the size of the reception buffer varies according to the change in the free space. For example, if the free space is large, the size of the reception buffer becomes large, and if the free space is small, the size of the reception buffer becomes small. As described above, since the reception buffer size dynamically changes according to the free space of the memory, the memory utilization efficiency is always good.

In a preferred embodiment, the upper limit of the receiving 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]

FIG. 1 is a block diagram showing a functional configuration of a printer according to the present invention.

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
It 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. Memory 1
In order to secure the receiving buffer 7, the work area 9, and the image buffer 11 in 3 and control their sizes,
A process called a memory management unit 15 operates.

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 indicates whether or not to dot each pixel of the image to be printed. A set of binary values (hereinafter referred to as image data) is generated. 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
The image is actually formed using a color former on a hard copy medium such as paper. 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.

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 interpreter 17 reads out the print data. The work area 9 is a memory area for storing information necessary for the command interpretation unit 17 to generate image data from print data, such as a font downloaded from the host computer 1. The image buffer 11
This 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.

As described above, if the image buffer 11 is not secured to provide image data to the print engine 21 in synchronization with the speed of the print engine 21, the print engine 21 performs printing. This is because it cannot be executed normally.

For this reason, as shown in FIG. 2, the work area 9 and the image buffer 11 are preferentially reserved in the heap memory 13 at the required sizes, and the reception buffer 7 is reserved in the remaining area. Then, the memory 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. Memory management unit 15
In this way, the size of the image buffer 11 is adjusted according to the progress of the generation and reading of the image data, and further, the reception buffer 9 is ensured 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.

If the size of the reception buffer 9 does not exceed the upper limit, print data from the host computer 1 can be continuously received, and the size of the reception 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 the 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.

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. In addition,
n is the total capacity of the heap memory 13.

First, the memory management unit 15 compares the total size of the image buffer 11 and the work area 9 with a value (n−n2) obtained by subtracting the upper limit value n2 of the reception buffer size from the total capacity n of the heap memory 13. It is determined whether or not b is sufficiently small (b << (nn-2)) (step S1). In short, it is determined whether or not 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.

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. It does not affect the adjustment as much as the image buffer 11 does.
Therefore, in the following, in order to simplify the description, the size of the work area 9 is assumed to be constant, the size of the portion excluding the work area 9 from the total heap memory 13 is set to n, and the size of the image buffer 11 is set to b. Do.

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 receive buffer size a is increased in accordance with the increase in the amount of received data so that the receive buffer 7 can accept all the received data (S2). . Thus, increasing the reception buffer size a as much as possible and accepting data from the host computer 1 contributes to shortening the release time of the host computer 1.

While continuing to receive the print data, it is checked whether or not the receiving buffer size a has reached the large upper limit n2 (S3). If a has reached n2 (YES in S3),
Command host interface 3 to host computer 1
The reception of data from the server is temporarily stopped (S4).

In parallel with the above operation, the command interpreter 17
Reads out print data from the reception buffer 7 and interprets it to create 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).

If the image buffer size b is increased and becomes less than b << (n-n2) (NO in S1), that is, if the free space of the memory 13 becomes insufficient, the control shifts to step S6 to receive the data. The upper limit of the buffer size a is switched to the smaller upper limit n1. That is, first, it is determined whether the reception buffer size a has fallen below the small upper limit value n1 (S6), and if a does not fall below n1 (N in S6).
O), the data reception suspension is further continued (S7), during which the reception buffer 7 is reduced in accordance with the decrease in the data in the reception buffer 7 as in step 5 already described, and
The image buffer 11 is enlarged with an increase in the generated image data (S9). As a result, when the receiving buffer 7 is reduced to be smaller than n1 (YE in S6).
S), the reception from the host computer 1 is started again,
With the increase in the amount of received data, the receiving buffer size a is increased again (S10). Then, when the reception buffer size a exceeds n1 (YE in S11).
S), the reception is stopped again (S12), and the process proceeds to step S9.

As described above, while the image data increases and the free space is not sufficient, the reception and the reception stop are repeated within a range where the reception buffer size a does not exceed the small upper limit value n1. When printing is started (YES in S8), 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 amount of data 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. .

As described above, depending on the size of the image buffer 11, if the free space is sufficiently large, a relatively large receiving buffer 7 is secured. If the free space is not sufficiently large, The receive buffer size is dynamically adjusted so that the receive buffer 7 is kept relatively small.

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.

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. The total width n on the vertical axis is the total capacity of the memory 13, n
1 is the upper limit of the receive buffer size, n2 is the upper limit of the receive buffer size, a is the size of the receive buffer 7, and b is the size of the image buffer 11 (or the total size of the image buffer 11 and the work area 9). Show.

First, at T0 before the start of print data reception,
Since almost no data is stored in the memory 13, the reception buffer size a has the minimum value a0 and the image buffer size b has the minimum value b0. From this initial state,
When the reception of the print data is started, since the free space is sufficient, the reception is performed without limitation, the reception buffer size a increases at a stretch, and reaches the size a1 equal to the large upper limit n2 at the time T1.

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, as at time T2, the image buffer size b
Becomes large enough to be equal to (n-n1), 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. And time T
In 4, when the reception buffer size a falls below the small upper limit value n1, reception is started again, and the reception buffer size a increases.

Here, for example, when printing is started at the time point Tp, the image data stored in the image buffer 11 decreases rapidly, 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.

The process shown in FIG. 4 is an example, and the buffer size does not always change exactly as in FIG. However, according to the size of the image buffer, control is performed so that a reception buffer as large as possible can be secured within a range allowed by the free space.
One skilled in the art should understand.

Also, in the above description, the upper limit value of the receiving buffer size is switched between two levels, large and small, but it 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 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 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]

 DESCRIPTION OF SYMBOLS 1 Host computer 3 Host interface 5 Printer 7 Receive 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)

[Claims] 1. A memory, a receiving buffer securing means for securing a receiving buffer for storing received data on the memory, and an image generating means for reading received data from the receiving buffer and generating image data from the read data. And an image buffer securing means for securing an image buffer for storing the image data generated by the image generating means on the memory, wherein the image buffer securing means is configured in accordance with an amount of the generated image data. A printer for adjusting the size of the image buffer, wherein the receiving buffer securing unit adjusts the size of the receiving buffer depending on the size of the image buffer. 2. The printer according to claim 1, further comprising a work area securing means for securing a work area for storing data necessary for the image generating means on the memory, wherein the receiving buffer securing means comprises: A printer, wherein the size of the reception buffer is adjusted according to the size of the image buffer and the work area. 3. The printer according to claim 1, wherein the receiving buffer securing unit compares when the size of the image buffer is larger and when the size of the image buffer is smaller. And a printer that secures the reception buffer to a larger size. 4. The printer according to claim 1, wherein said receiving buffer securing means is configured such that a free space of said memory determined depending on a size of said image buffer is larger than a predetermined reference. Means for determining whether or not, as a result of the determination, when the free space is larger than a predetermined reference,
Means for controlling the upper limit of the size of the reception buffer to a predetermined large upper limit, and, as a result of the determination, when the free space is smaller than a predetermined reference,
Means for controlling an upper limit value of the size of the receiving buffer to a predetermined small upper limit value. 5. A method of operating a printer, comprising the steps of: securing a reception buffer for storing reception data in a memory in the printer; reading the reception data from the reception buffer; and generating image data from the read data. Allocating an image buffer for storing the image data generated by the image generating step on the memory; and storing the image buffer according to an amount of the image data generated by the image generating step. Adjusting the size of the image buffer; and adjusting the size of the reception buffer depending on the size of the image buffer.