JPH11240227A - Printer and print system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high-speed printing by an inexpensive printer. SOLUTION: A printer 3 has a special hardware circuit 9. The special hardware circuit 9 receives a printing command from a host 1, processes image data thereby developing print images when the received command is a command sending the image data and, sends the image data to a printing mechanism 19 such as a printing head or the like. The special hardware circuit 9 sends the received command to a CPU 11 to process the command at the CPU 11 when the command is a command related to printing conditions or feeding of a paper, etc. The CPU 11 does not process the image data in principle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printer suitable for high-speed printing.

[0002]

2. Description of the Related Art A printer generally used in a computer system receives a series of print commands described in a predetermined printer control language from a host computer, interprets those print commands in order, and based on the interpretation result. Perform printing operation. Conventional printers use CP
U, ROM, built-in microcomputer consisting of RAM, etc., this microcomputer receives the print command from the host, interprets this, and drives and controls the mechanism such as the print head based on the interpretation result I have.

[0003]

Inevitably, the processing speed of the microcomputer in the printer is an important factor that affects the printing speed of the printer. Therefore, the conventional high-speed printer is equipped with a high-speed and high-performance CPU, but as a result, its price is considerably high.

Accordingly, it is an object of the present invention to provide a printer which is inexpensive and capable of high-speed printing.

[0005]

SUMMARY OF THE INVENTION The present invention provides a technique which is radically different from the conventional method of performing all command processing by a CPU. In general, a series of print commands received by a printer include a variety of print commands, such as a command for specifying various parameters relating to print conditions and the like, and a command for sending image data to be printed. Since most of this series of print commands is occupied by image data, most of the processing performed by the printer is also processing of image data.
The processing of the image data typically means extracting image data, which is usually compressed in a predetermined format and incorporated in a print command, from the command, decompresses the data, and drives a printing mechanism such as a print head. Data operations such as converting to a specific format suitable for printing (so-called “development of print image”) and transferring the print image to the print mechanism are performed in accordance with the operation timing of the print mechanism. . In the prior art, this image data processing is exclusively performed by the CPU. However, this processing is not particularly complicated processing for the CPU, but rather is an enormous repetition of simple data manipulation. However, the CPU is originally a device suitable for complicated processing and general-purpose usage, and cannot perform sufficiently high-speed operation in a task in which simple data manipulation is repeatedly performed. In such work, much of the work of the CPU is to move data into and out of the memory, and a huge number of times of data transfer is repeated sequentially through one CPU bus. Very high-speed processing cannot be expected due to restrictions on occupation time. On the other hand, among the print commands, commands that notify various parameters related to print conditions and the like have a small processing amount of each command, but have different processing contents for each command, and there are various commands. It is suitable for processing by the CPU.

Based on such reflection, the present invention mounts a dedicated hardware circuit for performing image data processing on a printer, and releases the CPU from the repetitive work of simple data operations. Since image data processing is performed by a dedicated hardware circuit, it is natural that high-speed printing can be performed as compared with the related art in which the processing is performed by a CPU. However, the advantages of the present invention are not limited thereto, and further, there is an advantage that the price increase due to this improvement is small. That is, since the processing content of the image data processing is relatively simple, the dedicated hardware circuit does not need to have such a complicated structure, and thus can be inexpensive. Also, since the printer CPU has been released from the image data processing, it does not need to be so high-speed and may be a low-cost one. Therefore, high-speed printing performance can be achieved without increasing the price as compared with the conventional technology using a high-speed CPU.

Although it is not impossible for dedicated hardware circuitry to perform all command processing, in a preferred embodiment, the dedicated hardware circuitry includes a print command that sends image data and a small number of other print commands. Only the commands are understood and processed, and a wide variety of other print commands are processed by the CPU. Then, the hardware circuit will not be unnecessarily complicated, and
The CPU can perform the type of command processing that the user is good at, and can most effectively achieve the above-described objects of high speed and low cost.

In a preferred embodiment, a dedicated hardware circuit communicates with a host computer to receive data, and determines whether or not the data is a predetermined command that can be processed by itself. Send to
Therefore, the CPU is not involved in the communication interface with the host computer, which leads to further higher speed.

In a preferred embodiment, the dedicated hardware circuit has its own memory separate from the RAM of the CPU.
The print image is sent to the printing mechanism without going through the printer. This configuration is also a device for releasing the CPU from image processing. In addition, as will be described later,
May generate a print image. In such a case, the print image generated by the CPU is received by the dedicated hardware circuit, developed in its own memory, and sent to the printing mechanism. This also reduces the load on the CPU and leads to higher speed.

In general, the order in which print commands are sent from the host is such that, for each page, a command group for specifying printing conditions and the like comes first, followed by a command for sending image data. Although this order is also adopted in the preferred embodiment of the present invention, the dedicated hardware circuit sends the command group for designating the printing conditions and the like to the CPU without understanding this (the dedicated hardware). Such a state of the circuit is referred to as a "give-up mode"), which allows the CPU to understand and process these commands. Then, the host-side printer driver wakes up the dedicated hardware circuit from the give-up mode before starting to send a command for sending image data after the command group for specifying the printing conditions is completed. A special command ("restart command") for instructing the CPU to do this is sent, and after this restart command, a considerable amount (for example, tens of bytes) of meaningless data (NU
LL data). With this command configuration, the dedicated hardware circuit wakes up from the give-up mode by the restart command immediately before receiving the image data command, but only meaningless data is sent until completely awakened. You will only receive image data commands after waking up. As a result, the dedicated hardware circuit can reliably enter the image data processing.

Further, in a preferred embodiment, the firmware of the CPU is fully prepared so that it can understand all commands that may come from the host and perform all processing including image data processing by the CPU. . Accordingly, even if the host-side printer driver is an old version and an image is sent using an old version of a print command that the dedicated hardware circuit cannot understand, the printer understands those print commands with the CPU and performs printing. The image can be expanded and printed normally. Also, for example, when the printer is connected to a network and receives image data (for example, an image of a banner) from the network OS of the network server instead of the printer driver, the printer processes the image with the CPU and prints the image. Is possible.

[0012]

FIG. 1 shows the configuration of an embodiment of the present invention.

A printer 3 is connected to the host computer 1 via a local interface or a network. The host computer 1 has a printer driver 5 for the printer 3. The printer driver 5 generates a series of print commands described in a predetermined printer control language that can be understood by the printer 3, and generates a series of print commands. A command is sent to the printer 3 through the OS.
In simple terms, a series of print commands is such that, for each page, a print command group for specifying print conditions and the like is sent first, and a print command group for sending image data follows.

In this embodiment, the image data embedded in the print command has been subjected to rasterization, color conversion, half-toning, interlacing, and the like on the printer driver 5 side (typically, It is assumed that the number of gradations of each color component value of each pixel is CMYK raster image data (two gradations or several gradations) which is the same as the expression capability of the printer 3 and is compressed by a certain method. However, this is not necessarily the case, and other image data forms (for example, full-color RGB raster data before color conversion, halftoning, or interlacing processing, for example) may be used. The degree of complexity of the image data processing to be performed on the printer 3 side varies depending on the form of the image data in the print command. In the case of the present embodiment, however, the printer 3 side performs color conversion, halftoning, and the like. Since there is no need to perform interlace processing, the image data processing is the simplest.

The printer 3 has a dedicated hardware circuit 9 for performing image data processing. This dedicated hardware circuit is, for example, an ASIC (Applicat
ionSpecific IC), not a computer that runs software on a CPU. On the other hand, CPU1
1, a microcomputer 17 including a ROM 13, a RAM 15, and the like are also mounted, and a dedicated hardware circuit 9 is connected to a bus of the CPU 11. The microcomputer 17 mainly performs processing (for example, print command processing relating to printing conditions and the like) that is not performed by the dedicated hardware circuit 9 among the processing that needs to be performed by the printer 3. Is programmed to process all types of print commands that the printer 3 may receive. Also, a printing mechanism 19 such as a print head for actually printing a print image on paper using a colorant.
Are also connected to the dedicated hardware circuit 9.

The dedicated hardware circuit 9 performs a communication interface process with the host computer to receive data from the printer driver 5, and a command for analyzing the received data and switching its transfer destination. An analysis circuit 13 is provided. A small number of predetermined print commands are registered in the command analysis circuit 23 in advance, and the command analysis circuit 23 determines whether the received data is the registered command. The registration commands include, first, CMY after rasterization, color conversion, halftoning, and interlace processing.
There is a print command (hereinafter, referred to as a “raster image command”) that sends K raster image data.
There are a few commands such as FF (form feed) and paper feed control. If the received command is a registration command, the command analysis circuit 13 transfers the raster image command to the print image developing circuit 15 and
The command for paper feed control is transferred to the CPU 11. Also, the received data does not correspond to the registration command (that is,
If the received data cannot be understood), the command analysis circuit 13 stops analyzing the data and the subsequent received data, and transfers all of the data to the CPU (this state is referred to as "give-up mode"). .

The dedicated hardware circuit 9 further includes a print image developing circuit 25, a memory for an image buffer 29, and a print image developing circuit 31. The print image expansion circuit 25 interprets the raster image command received from the command analysis circuit 23, extracts a CMYK raster image, decompresses and decompresses the raster image, and converts the format in the command into a format suitable for driving the printing mechanism 19. C
The image is recombined into a MYK raster image (hereinafter, referred to as a "print image"), and an image buffer 29 is secured in a memory, and the print image is developed in the image buffer 29. The print image transfer circuit 31 transfers the print image in the image buffer 29 to the print mechanism 19 in accordance with the operation timing of the print mechanism 31.

In the present embodiment, the image data processing in the print image expanding circuit 25 is as simple as the decompression of the compression and the rearrangement of the format as described above. This is preferable from the viewpoint of development. However, it is also possible to adopt a configuration in which part or all of the color conversion, half-toning, and interlace processing performed by the printer driver 5 can be performed by the print image developing circuit 25. In such a configuration, the load on the printer driver 5 is reduced, which leads to further speedup.

The dedicated hardware circuit 9 further includes a CP
The print image generated by U11 is stored in the image buffer 29.
And a CPU image development circuit 27 for developing the image data into the image data. The case where the CPU image development circuit 27 operates is that the host side printer driver 5 uses an old version print command that is not compatible with the printer 3 and is not registered in the dedicated hardware circuit. In the case where image data is sent, or when the printer 3 is connected to a network, the network
This is a case where image data such as a banner is received from S. In such a case, since the command analysis circuit 23 cannot understand the received data and enters the give-up mode and transfers all the received data to the CPU 11, the CPU 11 interprets the command of the received data and generates a print image. become. The print image generated by the CPU 11 is expanded in the image buffer 27 by the CPU image expansion circuit 27 and transferred to the printing mechanism 31 in the same manner as described above.

The microcomputer 17 including the CPU 11, the ROM 13, the RAM 15, and the like is programmed so as to be able to perform all kinds of command processing as described above.
Processing of commands related to FF and paper feed control is performed. In addition, as described above, processing of image data sent by an old version of a print command that cannot be understood by the dedicated hardware circuit 9 and image data sent from the network OS are also exceptionally performed.

Further, the microcomputer 17
Supplies a restart signal to the command analysis circuit 23 of the dedicated hardware circuit 9 in response to a predetermined restart command from the host computer 1 to wake up the command analysis circuit 23 from the give-up mode (that is, A process of returning to a state in which command analysis can be performed (return to the “normal mode” in the present invention) is also performed. Typically, this restart is used in the following situations.
That is, as described above, in a series of print commands from the printer driver 5, a command group for specifying printing conditions and the like comes first for each page, and a raster image command group follows. Since the command analysis circuit 25 of the dedicated hardware circuit 9 is in the give-up mode while a command group for specifying a printing condition or the like comes,
At the end of that, it is restarted so that subsequent raster image commands can be processed.

The operation of the printer 3 under the above configuration is as follows.
This will be further described with reference to FIGS. FIG. 2 is a state transition diagram of the command analysis circuit 23 of the dedicated hardware circuit 9, and FIG. 3 is a state transition diagram of the CPU 11.

When the power of the printer 3 is turned on, a reset signal is input to the dedicated hardware circuit 9 and the CPU 11, and both become idle states (states waiting for commands) 41 and 51. Thereafter, the printer driver 5 of the host sends a series of print commands. As described above, a command group for designating print conditions and the like comes first for each page, and thereafter, a raster image command group and the like. In this order, a command group for paper feed control and the like come, and an FF command comes at the end of each page.
At that time, the printer driver 5 sends the above-mentioned restart command after sending a command group for designating the first printing condition or the like before sending a subsequent raster image command group or the like. To this restart command, NULL data of an amount (for example, several tens of bytes) sufficient to cover the time required for restart (wake-up) of the command analysis circuit 25 is added.

When such a series of print commands comes,
The command analysis circuit 25 of the dedicated hardware circuit 9 analyzes the received data. However, when the command for designating the printing conditions or the like is first received, the command cannot be understood (not a registered command). The state shifts to the state 47 and returns to the head of the command and transfers the command to the CPU 11. Thereafter, the command analysis circuit 25 enters the state 49, stops the command analysis, and transfers all subsequent received commands to the CPU as they are.
The states 47 and 49 are the give-up mode 50 (the states other than the give-up mode 50 are the “normal mode” in the present invention).

As shown in FIG. 3, when the CPU 11 is in the idle state 51 at the time of startup, when a command group designating printing conditions and the like is transferred from the command analysis circuit 25, the CPU 11 enters the state 53, and Is performed. When each command processing is completed, the CPU 11 returns to the idle state 51 and repeats the operation of receiving and processing another command again. When the command group relating to the printing conditions and the like has been completed, the CPU 11 receives the restart command as described above. Therefore, the CPU 11 shifts to the state 59, outputs a restart signal to the command analysis circuit 23, and returns to the idle state 51 again.

As shown in FIG.
Receives a restart signal from the CPU 11 and returns to the idle state 41 (wakes up). During the delay time from the restart signal to the idle state 41, the NU attached to the restart command
The LL data is transferred to the CPU 11. When the CPU 11 receives the NULL data as shown in FIG. 3, the CPU 11 enters the state 55 and discards the NULL data. When the command analysis circuit 23 enters the idle state 41, the command analysis circuit 23 receives the remaining NULL data and enters the state 45, and
Read and discard the LL data. When the NULL data ends,
The command control unit 23 receives a raster image command, F
Since a registration command such as F or a command related to paper feed control is received, the state becomes state 43 and each reception command is processed. In this case, the raster image command is sent to the print image developing circuit 25, and the paper feed control and FF commands are transferred to the CPU 11. The print image developing circuit 25 interprets the raster image command and develops a print image. When receiving a command for paper feed control or FF, the CPU 11 enters the state 53 and processes each command.

As described above, high-speed printing is realized by the dedicated hardware circuit 9 and the CPU 11 sharing the appropriate processing.

The embodiment of the present invention has been described above.
These embodiments are merely examples for describing the present invention, and are not intended to limit the present invention only to these embodiments. Therefore, the present invention can be implemented in various forms other than the above-described embodiment.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a command analysis circuit 2 of a dedicated hardware circuit 9;
3 is a state transition diagram.

FIG. 3 is a state transition diagram of a CPU 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Host computer 3 Printer 5 Printer driver 9 Dedicated hardware circuit 11 CPU 17 Microcomputer 19 Printing mechanism 21 Host interface circuit 23 Command analysis circuit 25 Print image expansion circuit 27 CPU image expansion circuit 29 Image buffer 31 Print image transfer circuit

Claims (15)

[Claims] 1. A printer that receives a series of print commands and drives a print mechanism based on the print commands, processes image data embedded in the print commands to generate a print image to be sent to the print mechanisms. Printer with dedicated hardware circuitry to 2. The apparatus further comprises a microcomputer, wherein the dedicated hardware circuit includes a predetermined part of a variety of print commands included in the series of print commands, including a print command for sending the image data. 2. The printer according to claim 1, wherein only the print command is processed, and the microcomputer processes at least one of the various types of print commands except for the predetermined part of the print commands. 3. An interface circuit for receiving the series of print commands; a print image development circuit for processing the print command for transmitting the image data to generate the print image; A command analysis circuit that analyzes a print command received by the interface circuit, transfers a print command that sends the image data to the print image development circuit, and transfers the other print command to the microcomputer. Item 2. The printer according to Item 2. 4. The dedicated hardware circuit is a memory for expanding the print image, wherein the dedicated hardware circuit is a unique memory different from the memory of the microcomputer, and the print image is expanded in the unique memory. 3. A printer according to claim 2, further comprising a print image transfer circuit for transferring the print image to the printing mechanism. 5. The printer according to claim 4, wherein said dedicated hardware circuit further comprises a CPU image development circuit for receiving the print image generated by said microcomputer and developing the print image in said unique memory. 6. The dedicated hardware circuit receives the series of print commands, and in a normal mode, when the received print command is the predetermined partial print command, understands the received print command. When the received print command is not understood,
Thereafter, the mode is changed to the give-up mode, and the received command and the subsequent command are transferred to the microcomputer without understanding all the commands.The microcomputer understands and processes the command received from the dedicated hardware circuit, and 3. The printer according to claim 2, wherein when the received command is a predetermined restart command, a restart signal is given to the dedicated hardware circuit to return from the give-up mode to the normal mode. 7. The restart command is added with meaningless data of an amount sufficient to cover a time required for the dedicated hardware circuit to return from the give-up mode to the normal mode. 7. The printer according to claim 6, wherein the dedicated hardware circuit in the normal mode reads and discards the meaningless data. 8. The printer according to claim 2, wherein said microcomputer is capable of processing substantially all print commands that may be included in said series of print commands. 9. A print system comprising: a host computer having a printer driver; and a printer that receives a series of print commands generated by the printer driver and drives a printing mechanism based on the print commands. A dedicated hardware circuit for processing image data embedded in the print command to generate a print image to be sent to the printing mechanism. 10. The printer further includes a microcomputer, wherein the dedicated hardware circuit includes a predetermined command including a print command for transmitting the image data among various types of print commands included in the series of print commands. 10. The print system according to claim 9, wherein the microcomputer processes only a part of the print commands, and the microcomputer processes at least other print commands of the various types of print commands except for the predetermined part of the print commands. . 11. The printer driver, when sending the series of print commands, sends a predetermined restart command when switching from the other print command to the predetermined partial print command, The wear circuit receives the series of print commands, and in the normal mode, when the received print command is the predetermined partial print command, understands and processes the received print command, and executes the received print command. When the command cannot be understood, the mode is changed to the give-up mode, and the received command and subsequent commands are transferred to the microcomputer without understanding all the commands.The microcomputer receives the command from the dedicated hardware circuit. Understands and processes the command, and the received command is When a preparative command, the printing system according 請 10, wherein to said dedicated hardware circuit gives a restart signal to return from the give-up mode to the normal mode. 12. The printer driver adds, to the restart command, an amount of meaningless data sufficient to cover a time required for the dedicated hardware circuit to return from the give-up mode to the normal mode, 12. The printing system according to claim 11, wherein the computer and the dedicated hardware circuit in the normal mode read and discard the meaningless data. 13. A dedicated hardware circuit that receives a series of print commands and processes only a predetermined part of the various types of print commands included in the series of print commands, and the series of print commands. A microcomputer that processes other print commands except for the predetermined part of the various types of print commands included in the host computer, and sends the series of print commands to the printer. When sending the series of print commands, when switching from the other print commands to the predetermined part of the print commands,
A host computer that sends a reset command to instruct the microcomputer to restart the dedicated hardware circuit. 14. The host computer according to claim 13, wherein a predetermined amount of meaningless data to be discarded by said dedicated hardware circuit and said microcomputer is added to said restart command. 15. A dedicated hardware circuit that receives a series of print commands and processes only a predetermined part of various types of print commands included in the series of print commands, and the series of print commands. A microcomputer that processes other print commands except for the predetermined part of the various types of print commands included in the host computer, and sends the series of print commands to the printer. When sending the series of print commands, when switching from the other print commands to the predetermined part of the print commands,
A computer-readable recording medium carrying a printer driver program for causing a computer to function as a host computer that sends a reset command for instructing the microcomputer to restart the dedicated hardware circuit.