JP2000203093A - Printing output apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a printing speed greatly. SOLUTION: Each of a head control circuit and a head transmission memory are set by two systems. A CPU 1 alternately repeats transmission of image data to a first head control circuit 3a and transmission of image data to a second head control circuit 3b. During the transmission of image data to the first head control circuit 3a by the CPU 1, a direction conversion process at the second head control circuit 3b and a process for storing printing output data obtained by the conversion process into a second head transmission memory 4b are carried out. During the transmission of image data to the second head control circuit 3b by the CPU 1, a direction conversion process at the first head control circuit 3a and a transmission process for printing output data obtained by the conversion process to a first head transmission memory 4a are carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a print output apparatus for printing out image data such as drawings created by a CAD system or the like using, for example, an ink jet head or the like. The present invention relates to a print output device in which the direction of the dot arrangement is different from the direction of the dot arrangement of the data to be printed out.

[0002]

2. Description of the Related Art In a print output device such as a raster plotter using an ink jet head or a thermal head, a print scan of a print head on a print sheet is performed once.
Generally, print output for several to several tens of lines corresponding to the number of nozzles of the recording head is performed. In this case, a dot row direction conversion circuit (head control circuit) for vertically and horizontally converting the data in order to match the horizontal reference bitmap data developed in the image memory with the direction (vertical direction) of the nozzles of the recording head. After the direction of the dot row of the data is changed through the data, the data is stored in the head transfer memory and finally transferred to the print head.

[0003]

However, in a conventional print output apparatus, after writing data to a head control circuit that performs vertical / horizontal conversion of data, the vertical / horizontal conversion is performed by this circuit, and then the data is written to a head transfer memory. Since the operation is performed, the next data cannot be written to the head control circuit until the converted data is completely transferred from the head control circuit to the head transfer memory. For this reason, there is a problem that it takes too much time from reading of the data to be converted to completely writing the converted data in the head transfer memory. Therefore, the conventional print output device has a problem that the upper limit of the print speed of the inkjet head is limited by the time required for writing to the head transfer memory, and the print speed cannot be sufficiently improved.

[0004] The present invention has been made in view of such problems, and an object of the present invention is to provide a print output apparatus capable of greatly improving the printing speed.

[0005]

According to the present invention, there is provided an image memory for storing image data to be printed and output in the form of bitmap data, and a direction of arrangement of dot rows of image data serving as an access unit of the image memory. Dot row direction conversion means for converting the direction of the arrangement of dot rows of print output data, which is a unit of print output, data transfer means for reading image data from the image memory and transferring the read image data to the dot row direction conversion means, A head transfer memory for storing print output data obtained by the direction conversion by the dot row direction conversion means; and a recording head for executing a print output operation based on the print output data appropriately transferred from the head transfer memory. A print output device, comprising two systems each of said dot row direction conversion means and head transfer memory,
The data transfer means alternately repeats transfer of image data to the first dot row direction conversion means and transfer of image data to the second dot row direction conversion means. During the transfer of the image data to the dot row direction converting means, the direction conversion processing in the second dot row direction converting means and the processing for storing the print output data obtained by this in the second head transfer memory are executed. During the transfer of the image data to the second dot row direction conversion unit by the data transfer unit, the direction conversion processing in the first dot row direction conversion unit and the first head transfer of the print output data obtained by this. And performing a transfer process to a memory.

According to the present invention, there are provided two systems of dot row conversion means and a head transfer memory, and the first (second) dot row conversion means performs direction conversion processing and transfers to the first (second) head transfer memory. During the data transfer of the second (first)
Since the process of transferring the next image data to the dot row conversion means is executed, the process of data direction conversion does not have to wait at each stage, and the prompt conversion process of the data to be converted can be performed. Will be possible. As a result, the printing speed can be significantly improved as compared with the related art.

The image memory and the first and second head transfer memories are, for example, band memories having a capacity corresponding to a capacity printed and output by one or several scans of the recording head. The second dot row direction converting means performs a direction changing process on the image data of the band printed and output by the scanning of the next recording head, and performs the first and second
In the head transfer memory.

Further, for example, the first and second head transfer memories respectively store image data of a plurality of colors having different combinations, and print output data stored in the first head transfer memory. And the print output data stored in the second head transfer memory is data that is arranged in a staggered manner for each line on the output image.
A clear color image can be obtained with a small memory capacity.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a main configuration of an inkjet plotter according to one embodiment of the present invention. The CPU 1 is a CAD system (not shown)
Image data provided in the form of vector data, compressed image data, or the like from an image scanner or the like is developed on the main memory 2 in the form of bitmap data. Also, CPU
Reference numeral 1 denotes a data transfer unit that appropriately reads out bitmap data stored in the main memory 2 and transfers the data to the head control circuits 3a and 3b alternately. The head control circuits 3a and 3b are dot row direction conversion means, execute a vertical / horizontal conversion process internally, and transfer the converted print output data to the head transfer memories 4a and 4b, respectively. Also,
The head control circuits 3a and 3b include a head transfer memory 4a,
Data to be output is read from 4b and transferred to the inkjet head 5. The head control circuit 3a and the head transfer memory 4a, and the head control circuit 3b and the head transfer memory 4b can be formed of the same gate array. An encoder output from a linear encoder 6 including a scale and a sensor is supplied to the CPU 1. The CPU 1 generates a timing fence signal based on the encoder output and supplies the timing fence signal to the inkjet head 6. The ink jet head 6 performs a process of taking in data to be output and a print output operation based on the timing fence signal.

FIG. 2 is a diagram schematically showing an image of image data to be printed out. Now, assuming that the range that can be printed by one scan of the inkjet head 5 is one band, the images 10 to be printed out are sequentially formed by the reciprocating operation of the head 5 in the horizontal direction as indicated by the arrow in the drawing. To go. FIG. 3 is a diagram showing bit map data for one band stored in the main memory 2 in correspondence with an actual drawing. Now, assuming that the number of nozzles of the head 5 is 64, the bitmap data for one band is 6 bits.
That is, 4 lines × the number of horizontal dots. Here, assuming that one word, which is the unit of access, is 32 bits, and if n lines of data are stored in one line, the number of horizontal dots is 32n dots. Hereinafter, for convenience of explanation, the i-th line is Li, the j-th word is Wj,
A bit is represented by Bk, and one-word data as a unit of access is represented by Li / Wj.

On the other hand, the print output data stored in the head transfer memory 4a is, for example, as shown in FIG.
The third word is data L0 / W0, L1 / W0, L2
/ W0,..., L31 / W0 is composed of 32 bits of data obtained by collecting B31, and the second word is also composed of B30 of those data, consisting of 32 bits of data. In the print output data stored in the head transfer memory 4b, for example, as shown in FIG. 4B, the first word is data L32 / W0, L33 / W0, L34 / W.
.., L63 / W0 consist of 32-bit data collected from B31, and the second word also consists of 32-bit data collected from B30 of those data.

In order to perform such a vertical / horizontal conversion, each of the head control circuits 3a and 3b is provided with, for example, a vertical / horizontal conversion circuit as shown in FIG. In the case of this example, 32 words of image data Li / Wj to Li + 31 /
Wj is read continuously and each of the registers 11 ₀ , 11 ₁ , 1
1 _2, ..., stored in 11 _31, each of the registers 11 _0, 11 _1,
11 _2, ..., 11 by reading the data serially in order from ₃₁ to 32 bit, the print output data aspect conversion is obtained, which is the head transfer memory 4a, 4
b.

Next, the operation of the plotter thus configured will be described. FIG. 6 is a timing chart showing the operation of the plotter in comparison with a conventional example. First,
The conventional transfer timing will be described with reference to FIG.
Since only one system was provided, CPU 1
32 words of data L0 / W0 are supplied to the head control circuit 3a.
After writing the data of L31 / W0, the head control circuit 3a is in a standby state until the head control circuit 3a completes the vertical / horizontal conversion and the transfer of the print output data to the head transfer memory 4a. Therefore, for example, in order to store data of 64 lines × 64 dots from L0 / W0 to L63 / W1 in the head transfer memory 4a, the CPU 1 controls the head control circuit 3
a time T1 required for writing 32 words of data to a,
A time T3, which is four times the time obtained by adding the time T2 required to transfer data after conversion from the head control circuit 3a to the head transfer memory 4a, is required.

On the other hand, according to the plotter of this embodiment, as shown in FIG. 1B, the CPU 1 accesses the main memory 2 to access the data L0 / W0 to 32-word data L0 / W0.
L31 / W0 is continuously read and the head control circuit 3a
After the head control circuit 3a converts the 32 words of data L0 / W0 to L31 / W0 into vertical and horizontal data and transfers the data to the head transfer memory 4a, the next data L
32 / W0 to L63 / W0 can be written to the head control circuit 3b. While the head control circuit 3b vertically and horizontally converts the data L32 / W0 to L63 / W0 for 32 words and transfers the data to the head transfer memory 4b,
The CPU 1 sets the next 32 words of data L0 / W1 to L0
31 / W1 can be read continuously and written to the head control circuit 3a. In this case, the same amount of data as described above, that is, data of 64 lines × 64 dots from L0 / W0 to L63 / W1 is transferred to the head transfer memories 4a and 4b.
Requires only T4 = 4T1 + T2,
Significant time reduction is possible.

The transfer timing from each of the head transfer memories 4a and 4b to the ink jet head 5 may be set at an arbitrary timing when all the data of the next band is stored in each of the head transfer memories 4a and 4b. This timing may be given from the head 5 in synchronization with the timing fence signal. 1 on the head 5 side
If a memory having the capacity of the band is mounted, the data can be transferred collectively at the time of non-recording operation when the head 5 returns.

In the above embodiment, as shown in FIG. 7A, the upper half (data without hatching) of one band is stored in the first head transfer memory 4a, and the lower half is stored. (The data shaded) is transferred to the second head transfer memory 4
b, the left half is stored in the first head transfer memory 4a and the right half is stored in the second head transfer memory 4a, as shown in FIG.
May be stored in the head transfer memory 4b.
Also, as shown in FIG. 3C, data stored in the first head transfer memory 4a and data stored in the second head transfer memory 4b
May be arranged in a zigzag pattern.

In the above-described embodiment, a color image is not described for simplicity of explanation. However, when a color image is printed out, the head transfer memories 4a and 4b described above are stored in, for example, C (cyan). ), M (magenta), Y (yellow), and K (black). In order to improve the clarity of a color image, when printing six colors in which LC (light cyan) and LM (light magenta) are added to CMYK, CMY is used as the first head transfer memory 4a.
A second head transfer memory 4 having memories for four colors of K
b is provided with memories for four colors of LCLMYK. Then, as shown in FIG. 7C, the head transfer memory 4
If the stored data of a and 4b are arranged in a staggered grid pattern, the sharpness can be improved by alternately changing the combination of colors without preparing memories for six colors in the memories 4a and 4b. It is possible to print out a high color image.

The nozzle rows of the head 5 do not need to be strictly arranged in a straight line. Normally, the nozzles may be arranged in a staggered or oblique manner due to the arrangement space. In this case, it is sufficient to add a space bit to the data converted vertically and horizontally, and it goes without saying that this case is also included in the present invention.

In the above embodiment, the capacity of the band memory is described as the capacity printed in one scan of the ink jet head. However, the capacity of the band memory is limited to several scans of the ink jet head, for example, 2 times. It may have a capacity of data to be printed in each scan.

[0020]

As described above, according to the present invention, there are provided two systems of the dot string conversion means and the head transfer memory, and one dot string conversion means performs the direction conversion processing and the data transfer to the corresponding head transfer memory. Is performed, the process of transferring the next image data to the other dot string converting means is executed, so that the conversion is performed without waiting at each stage of the data direction converting process. This makes it possible to quickly convert the data to be processed, thereby greatly improving the printing speed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main configuration of an inkjet plotter according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a printing operation of the plotter.

FIG. 3 is a diagram showing bit map data for one band stored in a main memory.

FIG. 4 is a diagram showing print output data for one band stored in a head transfer memory.

FIG. 5 is a block diagram of a vertical / horizontal conversion circuit provided in a head control circuit.

FIG. 6 is a timing chart showing data conversion timing of the plotter.

FIG. 7 is a diagram showing an example of an arrangement of data stored in two head transfer memories.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... Main memory, 3a, 3b ... Head control circuit, 4a, 4b ... Head transfer memory, 5 ... Ink jet head

Claims (3)

[Claims] An image memory for storing image data to be printed and output in the form of bitmap data, and a print output as a unit of print output indicating a direction of arrangement of dot rows of image data as an access unit of the image memory. Dot row direction converting means for converting the direction of the arrangement of dot rows of data; data transfer means for reading image data from the image memory and transferring the read image data to the dot row direction converting means; A print output device comprising: a head transfer memory that stores print output data obtained by the conversion; and a recording head that executes a print output operation based on print output data appropriately transferred from the head transfer memory. A column direction conversion unit and a head transfer memory, each of which includes two systems; The transfer of the image data to the direction conversion means and the transfer of the image data to the second dot row direction conversion means are alternately repeated, and the transfer of the image data to the first dot row direction conversion means by the data transfer means Between the second dot row direction conversion means and the process of storing the print output data obtained by this in the second head transfer memory, the second dot row by the data transfer means. During the transfer of the image data to the direction converting means, the direction conversion processing in the first dot row direction converting means and the processing for transferring the print output data obtained thereby to the first head transfer memory are executed. A printout device characterized by the following. 2. The image memory and the first and second head transfer memories are band memories having capacities corresponding to capacities printed and output by one or several scans of a recording head. The second dot row direction conversion means performs a direction conversion process on the image data of the band printed and output by the scanning of the next recording head and stores the image data in the first and second head transfer memories. The print output device according to claim 1. 3. The first and second head transfer memories respectively store image data for a plurality of colors having different combinations, and print output data stored in the first head transfer memory; 3. The print output apparatus according to claim 1, wherein the print output data stored in the second head transfer memory is data arranged in a staggered manner for each line on an output image.