JP2008012817A - Printer and data transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer discharging ink from its head, or the like, which can reduce a load to a CPU used for various kinds of controls, in a data transfer to the head. <P>SOLUTION: The printer provided with the head 6 for making printing on a printing medium by scanning the medium, based on data transferred, comprises: the CPU 2 for controlling the printer; a memory 5 for storing the data transferred to the head; and a transfer unit for transferring the data stored in the memory, to the head. The transfer unit executes the transfer of data to be used for one scanning of the head 1 without an intervention of the CPU after it is set up by the CPU. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet printer that discharges ink from a head unit, and more particularly to a printer that can suppress a load on a CPU used for various controls in data transfer to a head unit.

  2. Description of the Related Art Conventionally, ink jet printers are known in which a head including a plurality of nozzles that eject ink is moved relative to a print medium, and an image is formed on the print medium by ink ejected (ejected) from each nozzle. Yes.

  In such a printer, predetermined image processing is performed on the image data sent from the print request source, and the data is supplied to the head after the print data for the head is obtained. The data transfer to the head is divided into a plurality of times for the data for one scan (one pass) of the head due to the scale of the device such as a bus and a memory and the generation timing of print data to be transferred. Made.

For example, in the method described in Patent Document 1 below, the CPU responsible for controlling the printer generates an interrupt process at a rate of once every 8 fire cycles, takes out print data for 8 fires, and the data is once latched. Later, one fire is output to the print head.
JP 2000-33738 A

  However, in the conventional method described above, when transferring the data for one pass to the head, the CPU needs to intervene complicatedly, and the CPU is loaded.

  In addition, in this type of printer, there is a tendency to increase the number of nozzles and the number of heads, and accordingly, it is expected that the amount of data will increase and the control will become more advanced, and the load on the CPU will increase. The Therefore, a technique for reducing the CPU load in data transfer to the head is also desired in securing CPU resources.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet printer that discharges ink from a head unit, which can suppress a load on a CPU used for various controls in data transfer to the head unit, and the like. It is to be.

  To achieve the above object, according to one aspect of the present invention, there is provided a CPU including a head that scans a print medium based on transferred data and performs printing on the print medium, and a CPU that controls the printer. A memory for storing data to be transferred to the head; and a transfer unit for transferring the data stored in the memory to the head, wherein the transfer unit is used for one scan of the head. Data transfer is executed without intervention of the CPU after receiving the setting process by the CPU.

  Further, in the above invention, a preferred aspect is characterized in that a generation speed of data stored in the memory is faster than a transfer speed by the transfer unit.

  In the above invention, a preferred aspect is characterized in that the data transfer for one scan by the transfer unit is performed after the data for the one scan is stored in the memory.

  Furthermore, in the above invention, a preferred aspect is characterized in that two types of storage location and data length of the data to be transferred are set in the transfer unit by the setting process by the CPU. .

  Furthermore, in the above invention, a preferred aspect is characterized in that the two types of settings are for print data and for flushing data, respectively.

  In order to achieve the above object, another aspect of the present invention provides a control CPU, a memory for storing data, and a head that scans the print medium based on the data and prints on the print medium. In the data transfer method from the memory to the head in a printer comprising: a transfer of the data used for one scan of the head is performed without the intervention of the CPU after the setting process by the CPU That is.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a configuration diagram according to an embodiment of a printer to which the present invention is applied. The printer 1 shown in FIG. 1 is a printer according to the present embodiment. In the process of transferring data stored in the memory 5 to the head 6, the transfer setting process by the CPU 2 is performed only once for the data for one pass. The CPU load in the data transfer process is to be suppressed.

  A printer 1 according to the present embodiment is an ink jet printer as an example, and includes a CPU 2, an image processing unit 3, a DSP 4, a memory 5, a head 6, and the like as shown in FIG. A print request and its print data transmitted from the outside such as a host computer are stored in the memory 5 as input data. Thereafter, the received compressed print data is subjected to decompression processing, color conversion processing, halftone processing, pass separation processing, and data rearrangement processing by the image processing unit 3, DSP 4, etc., respectively. The subsequent data is output to the head 6 in an appropriate order. The head 6 sequentially ejects ink based on the transferred print data and executes printing on the print medium.

  The CPU 2 is a part that controls the operation of each part of the printer 1. As shown in FIG. 1, the image processing unit 3 includes a data reception unit 31, a decompression unit 32, a path decomposition unit 33, a rearrangement unit 34, a data transfer unit 35, a head output unit 36, and the like. Is composed of an ASIC.

  The data receiving unit 31 is a part that receives print data transmitted from a host computer or the like and stores the data in the memory 5 as input data. The decompressing unit 32 is a part that decompresses the received compressed print data.

  The pass separation unit 33 is a part that performs a process of dividing the print data after the halftone process for each scan (pass) of the head 6. The head 6 has a nozzle row having a plurality of nozzles for ejecting ink in the sub-scanning direction for each color, and sequentially ejects ink while moving in the main scanning direction. Since one line in the scanning direction) is printed by a plurality of scans (passes), it is necessary to distribute print data of one raster for each scan (pass), and such a pass separation process is performed.

  Next, the rearrangement unit 34 is a part that performs a process of rearranging the print data after the pass decomposition for each predetermined unit data.

  The data transfer unit 35 is a part for transferring the rearranged print data to the head 6 side, and is a characteristic part in the printer 1. Although the specific configuration and processing contents will be described later, when the print data for one pass stored in the memory 5 is transferred to the head output unit 36, only the transfer setting process by the CPU 2 is received once. Is executed by hardware.

  The head output unit 36 is a part that reads the print data transferred from the data transfer unit 35 and outputs it to the head 6 in an appropriate order. When the head 6 is multi-headed, the head output units 36 are provided as many as the heads 6. For example, when ten colors of ink are used in the printer 1 and three heads are provided, three head output units 36 are provided correspondingly.

  Next, the DSP 4 is a processor (Digital Signal Processor) that performs the color conversion process and the halftone process described above, reads predetermined print data stored in the memory 5, executes the process, and processes the processed data. Write back to the memory 5 again.

  The memory 5 is an external memory provided outside the image processing unit 3 and stores print data in a state received from the outside and in a state after the processing of each image processing described above in a predetermined area. Therefore, input data, decompressed data, data after halftone processing, data after pass decomposition, data after rearrangement processing, and the like are stored in the memory 5, respectively. The memory 5 is specifically composed of a RAM.

  Finally, the head 6 has a nozzle row for each ink color as described above, and sequentially ejects ink according to the print data sent from the head output unit 36 while moving in the main scanning direction to print on the print medium. This is the part to be implemented. The nozzle provided in the head 6 is provided with a piezo element (drive device). When a predetermined drive voltage (drive waveform) is applied from a control circuit (not shown), the piezo element The ink is distorted and discharged. Further, as described above, the head 6 may be a multi-head.

  FIG. 2 is a configuration diagram centering on the data transfer unit 35 which is a characteristic part of the printer 1. As shown in FIG. 2, the data transfer unit 35 issues a request to the memory 5 to read the print data after the rearrangement process described above, and the head output unit 36 reads the data read in response to the request from the head output unit 36. Forward to. At this time, the data transfer unit (for example, 128 bytes) from the memory 5 is larger than the data transfer unit (32 bytes) to the head output unit 36. In addition, the CPU 2 performs transfer setting for the data transfer unit 35, which is a start trigger for the transfer processing of print data for one pass. The head output unit 36 sequentially outputs the data received from the data transfer unit 35 to the head 6 at a predetermined timing.

  As shown in FIG. 2, the data transfer unit 35 includes a register 351 and a transfer unit internal memory 352. Contents such as “address 1”, “address 2”, “transfer length 1”, “transfer length 2”, “transfer destination”, and “pointer” are set in the register 351 according to the transfer setting of the CPU 2. “Address 1” and “Address 2” indicate addresses in the memory 5 from which data is read, respectively. “Transfer length 1” and “Transfer length 2” are “Address 1” and “Address 2”, respectively. This indicates the length of data read from the address indicated by “”.

  The data for one pass used by the head 6 includes print data for actual ink ejection and flushing data for nozzle flushing. Here, as an example, assume that flushing data comes at the beginning of each pass. , “Address 1” and “Transfer length 1” are set with the leading address of the area in the memory 5 in which the flushing data is stored and the length of the flushing data, respectively. In “address 2” and “transfer length 2”, the head address of the area in the memory 5 storing the print data of the pass and the length of the print data are set.

  Normally, the flushing data is common regardless of the path. In this case, the flushing data is stored in one place in the memory 5, and “address 1” and “transfer” are performed in the data transfer of any path in which flushing is performed. The same content is set for “length 1”. In a path where flushing is not performed, “transfer length 1” is set to 0. On the other hand, since the print data normally differs for each pass, different contents are set in “address 2” for each pass. “Transfer length 2” is usually the same value within the same print job.

  The “transfer destination” and the “pointer” are used to switch the data transfer destination when the head 6 has multiple heads and the head output unit 36 has a plurality.

  The transfer unit internal memory 352 is a RAM for buffering data read from the memory 5, and data transfer to the head output unit 36 is performed from here.

  As shown in FIG. 2, the head output unit 36 includes a buffer 361. The buffer 361 is a RAM that stores the data transferred from the data transfer unit 35, and outputs data to the head 6 from here. This buffer 361 is provided with two surfaces (areas), and when one side outputs data to the head 6, the other side is controlled to receive data transfer from the data transfer unit 35.

  As described above, the printer 1 according to the present embodiment having the configuration as described above is characterized by the data transfer processing to the head 6 side, and the contents thereof will be described below. FIG. 3 is a flowchart illustrating the processing in the data transfer unit 35. Here, data transfer for one pass will be described.

  First, the data transfer unit 35 receives a transfer setting process by the CPU 2 (step S1). As a result, the above-mentioned “address 1”, “address 2”, “transfer length 1”, “transfer length 2”, “transfer destination” are stored in the register 351 in the data transfer unit 35 described above for the data for the path. , “Pointer” and other contents are set. Simultaneously with the transfer setting by the CPU 2, the head output unit 36 is also instructed to output data to the head 6 for the path, and based on this, the head output unit 36 transfers the data to be output to the head 6. A request is sent to the unit 35.

  Upon receiving the request (step S2), the data transfer unit 35 starts reading data from the memory 5 for data to be transferred to the head 6 (head output unit 36). First, a request is made to the memory 5 to transfer data having a length set in “transfer length 1” in the register 351 from an address set in “address 1” in the register 351 (step S3). . Specifically, when flushing is first performed in the path, a data transfer request is made by designating the address in the memory 5 in which the flushing data is stored and the length of the flushing data.

  FIG. 4 is a diagram schematically illustrating the state of data stored in the memory 5. FIG. 4A shows the state of the print data and flushing data stored in the memory 5. As described above, the flushing data is common data regardless of the path. Is stored in one place. In the example in the figure, the setting contents of “address 1” and “transfer length 1” in the request (S3) to the memory 5 described above correspond to “address 1” and “transfer length 1” shown in FIG. In this request, a request is made to transfer data corresponding to the length of “transfer length 1” from the position of “address 1”.

  When data is transferred from the memory 5 in response to the request, the data transfer unit 35 receives the data and stores it in the transfer unit internal memory 352 described above (step S4). As described above, the transmission unit of data transmission from the memory 5 to the data transfer unit 35 is determined (for example, 128 bytes). Normally, data of “transfer length 1” is transmitted in one transfer process. Since it cannot be performed, the transfer from the memory 5 and the reception and storage by the data transfer unit 35 are repeated a plurality of times (No in steps S4 and S5).

  When the requested data “transfer length 1” is received and stored (Yes in step S5), the data transfer unit 35 switches the data read contents. That is, a request is made to the memory 5 to transfer data having a length set in the “transfer length 2” of the register 351 from an address set in the “address 2” of the register 351 (step S6). .

  Specifically, an address in the memory 5 storing the print data of the pass and the length of the print data are designated and a data transfer request is made. In the example shown in FIG. 4, for example, address 2 ”and“ transfer length 2 ”shown in FIG. 4A correspond to the contents set in“ address 2 ”and“ transfer length 2 ”, and the request Then, a request is made to transfer data corresponding to the length of “transfer length 2” from the position of “address 2”. As described above, the print data is normally stored at different addresses in the memory 5 for each pass. Therefore, in the transfer process for different passes, for example, “x” in FIG. Will be specified.

  When data is transferred from the memory 5 in response to the request, the data transfer unit 35 similarly receives the data and stores it in the in-transfer unit memory 352 (step S7). Also in this case, the data for “transfer length 2” is usually divided and transmitted a plurality of times. That is, the transfer from the memory 5 and the reception and storage by the data transfer unit 35 are repeated until all the data for “transfer length 2” is completed (No in steps S7 and S8).

  When the requested data of “transfer length 2” is received and stored (Yes in step S8), the process of reading data from the memory 5 for the path is completed.

  On the other hand, the transfer process of the data read into the data transfer unit 35 to the head output unit 36 is performed independently in parallel with the above-described read process (S3-S8). After the request from the head output unit 36 to the data transfer unit 35 described above, the data read from the memory 5 and stored in the transfer unit internal memory 352 is sequentially transmitted in a predetermined transmission unit (for example, 32 bytes). 36 and stored in the buffer 361 described above. When this transfer and storage are repeated and one buffer 361 is filled, a request to transfer data to the buffer 361 to be filled again is issued from the head output unit 36 to the data transfer unit 35. Similarly, the transfer and storage process is repeated. The switching of the transfer destination buffer 361, the transfer to the transfer destination, and the storage are repeated in the same manner, and all the data in the path is transferred to the head output unit 36.

  When there is one head 6, there is also one head output unit 36, and data transfer is repeated alternately with respect to the two-side buffer 361 described above. Further, when the head 6 is a multi-head, there are a plurality of head output units 36, which head output unit 36 is to be transferred according to the contents set in the “transfer destination” and “pointer” of the register 351 described above. Is determined, and based on this, the transfer destination is switched. For example, when there are three head output units A, B, and C, the “transfer destination” is set with contents indicating the transfer order such as “AAABBBCCCAAA...” And “ABCABCABC. , “Pointer” is set to indicate the position in the transfer order at that time.

  In this way, the transfer process to the head output unit 36 is performed, and the data output from the head output unit 36 to the head 6 is also performed in parallel, and when the buffer 361 is filled with data by the transfer, Data output from the buffer 361 to the head 6 is started.

  Each of the data transfer processes described above is executed, data for one pass is transferred from the memory 5 to the head 6, and ink ejection to the print medium for the pass is executed based on the transferred data. It will be.

  FIG. 4B schematically shows data for one pass sent to the head 6. In the example of the figure, the data of the path needs to be supplied to the head 6 in the direction indicated by the arrow in the figure. However, in the transfer process in the printer 1, the setting process (interrupt process) by the CPU 2 is performed during the transfer process. Is performed once at the timing indicated by A (data transfer start timing), and the rest is processed by hardware.

  In the printer 1, since the target path data is transferred one after another by the hardware after the setting process by the first CPU 2, the data of the path at the time of starting the transfer process for the path. Must already be generated and stored in the memory 5, or the speed at which data to be transferred is generated is faster than the transfer speed.

  As described above, in the printer 1 according to the present embodiment, the data transfer unit 35 configured by hardware is provided, and when the data for one pass is transferred to the head 6, first, the CPU 2. After receiving the setting process according to, the transfer is executed without the intervention of the CPU 2. Therefore, it is possible to suppress the load on the CPU as compared with the conventional method for data transfer to the head.

  In addition, two sets of contents (“address 1”, “address 2”, “transfer length 1”, “transfer length 2”) are set for the data read from the memory 5 and are switched to print data and flushing data. Therefore, it is only necessary to store the flushing data common to each pass in one place in the memory 5, and it is not necessary to add to the print data of each pass, and the necessary memory area is kept small. Can do.

  In addition, when there are a plurality of heads, data transfer to each head can be switched, and it is possible to deal with multiple heads.

  Further, the above two sets of settings can be applied not only to print data and flushing data but also to the case of repeatedly transferring two different patterns of print data. In this case as well, the effect of suppressing the memory area can be obtained. .

  In the present embodiment, the above two sets of data are set, but only one set of data may be set. In this case, the data of each path including the flushing data is stored in the memory 5 so as to be located continuously from a predetermined address. Even in this case, the above effect of reducing the CPU load can be obtained. Furthermore, three or more sets of data may be set.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

1 is a configuration diagram according to an embodiment of a printer to which the present invention is applied. FIG. 2 is a configuration diagram centering on a data transfer unit 35 that is a characteristic part of the printer 1; FIG. 5 is a flowchart illustrating an example of processing in a data transfer unit 35. It is the figure which illustrated typically the mode etc. of the data stored in the memory.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Printer, 2 CPU, 3 Image processing unit, 4 DSP, 5 Memory, 6 heads, 31 Data receiving part, 32 Decompression part, 33 Path decomposition | disassembly part, 34 Rearrangement part, 35 Data transfer part (transfer unit), 36 head Output unit (transfer unit), 351 register, 352 memory in transfer unit, 361 buffer

Claims (6)

A printer comprising a head that scans a print medium based on transferred data and prints on the print medium,
A CPU for controlling the printer;
A memory for storing data to be transferred to the head;
A transfer unit for transferring the data stored in the memory to the head,
The printer, wherein the transfer unit executes the transfer of the data used for one scan of the head without the intervention of the CPU after receiving the setting process by the CPU. In claim 1,
A printer, wherein a speed at which data stored in the memory is generated is faster than a transfer speed by the transfer unit. In claim 1,
The data transfer of one scan by the transfer unit is performed after the data for one scan is stored in the memory. In any one of Claim 1 thru | or 3,
Two types of storage locations and data lengths of the data to be transferred are set in the transfer unit by the setting process by the CPU. In claim 4,
The two types of settings are for print data and for flushing data, respectively. A data transfer method from the memory to the head in a printer comprising: a control CPU; a memory for storing data; and a head that scans the print medium based on the data and prints on the print medium. There,
Transfer of the data used for one scan of the head is performed without the intervention of the CPU after the setting process by the CPU.

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