JP4576798B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus capable of shortening data transfer time to a recording head and realizing high-speed image recording.
[0002]
[Prior art]
In an inkjet recording apparatus that records an image by scanning a recording head in which a plurality of nozzles that eject ink are arranged in a direction crossing the conveyance direction of the recording medium, the image quality is reduced by reducing streak patterns called banding. In order to improve image quality, a recording method that thins out pixels, generally called interleaved or staggered, is employed when performing image recording by ejecting ink from a recording head.
[0003]
Conventionally, a technique described in Patent Document 1 is known as a technique that employs such a recording method. Each of the nozzles based on the image data includes a pulse generation circuit that outputs a signal multiplied by a multiplier circuit as a data transfer start signal and outputs a phase difference signal of encoder outputs having different phases as an ink ejection signal. The ink ejection from the above is made valid or invalid only by selecting the ejection signal thinned out at a constant cycle. According to this, since it is possible to perform printing control of pixels recorded at an arbitrary phase by selecting the ejection signal thinned out at a constant cycle, there is an advantage that recording in a free format is possible. ing.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-6382
[Problems to be solved by the invention]
In Patent Document 1, ink ejection is performed by selecting an ejection signal that is thinned out at a constant period, and all data is transferred to the recording head. Data was also sent, and data transfer was wasted.
[0006]
In recent years, in order to realize high-speed and high-definition image recording, the number of nozzles of the recording head has been greatly increased to increase the density, and the amount of data sent to the recording head has also increased. Accordingly, an increase in data transfer time due to waste of data transfer has become a problem. Such an increase in the data transfer time leads to an increase in the image recording time by the recording head, resulting in a problem that the image recording speed is lowered.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording apparatus that eliminates waste of data transfer to a recording head and can shorten the data transfer time.
[0008]
[Means for Solving the Problems]
The above problems are solved by the following inventions.
[0009]
According to the first aspect of the present invention, a recording head in which a plurality of nozzles are arranged is scanned in a main scanning direction that intersects the conveyance direction of the recording medium, and ink is ejected from the nozzles at a predetermined timing based on the ejection signal and ejection data. An ink jet recording apparatus for recording an image by discharging
Image data storage means for storing image data;
Signal generating means for generating a data transfer start signal to the recording head;
A thinning pattern storage unit that stores a thinning pattern for thinning out pixels in the main scanning direction, and a timing control unit that controls a start timing at which the ejection signal is turned on / off by a thinning pattern selected from the thinning pattern storage unit. by performing the thinning on the basis of the thinning pattern which is pre-selected for the data transfer start signal, a first thinning means for generating the discharge signal decimated,
Pixels for thinning out pixel data of lines in the main scanning direction of the image data based on a preset thinning number for the image data stored in the image data storage means in accordance with the data transfer start signal Ink jet recording apparatus comprising: a second thinning unit that generates the thinned discharge data by skipping data and outputs only the thinned discharge data to the recording head It is.
[0011]
According to a second aspect of the present invention, the second thinning means includes a thinning step storage means for storing a thinning step, a start pixel storage means for storing a position of a pixel to start thinning, the thinning step storage means, based on the information of the start pixel storage unit, an ink jet recording apparatus according to claim 1, characterized in that it has a discharge data selection means for selecting data to be transferred to the recording head.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a schematic configuration diagram illustrating an example of an ink jet recording apparatus. In the figure, reference numeral 1 denotes a recording medium that is continuously fed out from the original winding wound in a roll shape, and 2a denotes a conveyance roller for conveying the recording medium 1 in the direction of the arrow X. The transport roller 2 a is driven by the drive mechanism 3.
[0014]
As shown in the figure, the drive mechanism 3 transmits a conveyance motor 30, a drive pulley 32 connected to the conveyance motor 30 via a drive shaft 31, and a driving force of the drive pulley 32 via a belt 33. A driven pulley 34 is provided, and the driven pulley 34 and the transport roller 2 a are connected by a rotating shaft 4. Reference numeral 2b denotes a driven roller that presses the recording medium 1 against the conveying roller 2a.
[0015]
A recording head 5 performs image recording by ejecting ink onto the recording medium 1. Here, the recording head 5 is composed of a plurality of heads formed by arranging a plurality of ink ejection openings for ejecting ink of each color YMCK. However, the recording head 5 has a plurality of ink ejection openings for ejecting ink of the same color of the same color. It may consist of a single recording head.
[0016]
In each color head of the recording head 5, for example, a large number of nozzle holes are arranged in the arrangement direction of ink discharge ports (also referred to as nozzle holes).
[0017]
The recording head 5 is mounted on a carriage 6, and the carriage 6 is configured to be able to scan in a main scanning direction orthogonal to the arrow X direction that is the conveyance direction of the recording medium 1 by the driving force of the driving motor 7. Yes. Specifically, the carriage 6 is fixed to a scanning belt 8, the scanning belt 8 is stretched around a driving pulley 9 and a driven pulley 10, and the driving pulley 9 is connected to a driving shaft 11 of a driving motor 7. Accordingly, when the drive motor 7 is driven, the scanning belt 8 moves and the carriage 6 moves in the main scanning direction.
[0018]
In order to detect the position information of the carriage 6, a linear encoder (not shown) is provided along the main scanning direction, and a linear encoder signal is read by a sensor provided on the carriage 6 according to the movement of the carriage 6. It is configured.
[0019]
A scanning guide 12 regulates the movement of the carriage 6 in the main scanning direction. Usually, two regulating rods are used.
[0020]
In order to perform image recording using the ink jet recording apparatus having the above configuration, a long recording medium 1 wound in a roll shape is transported by a predetermined amount in the sub-scanning direction (downward direction in the figure) by a transport roller 2a. . With the conveyance of the recording medium 1 temporarily stopped, the recording head 5 scans in the main scanning direction while being regulated by the scanning guide 12. At this time, the recording head 5 performs recording by moving in the main scanning direction while ejecting ink, and further obtains a predetermined image by feeding the recording medium 1 in a predetermined amount according to the pixel pitch in the sub-scanning direction.
[0021]
FIG. 2 is a block diagram showing an outline of a drive unit of the ink jet recording apparatus according to the present invention. An outline of drive control of the recording head 5 will be described with reference to FIG.
[0022]
A position information signal (encoder pulse) in the main scanning direction of the carriage 6 from a linear encoder not shown in FIG. 1 is input to an ejection signal generation unit 200 controlled by the processor 100. The ejection signal generation unit 200 outputs an ejection signal to the recording head drive circuit unit 300 in accordance with the position of the carriage 6 in the main scanning direction. Upon receiving this ejection signal, the recording head drive circuit unit 300 receives the recording head 5. A predetermined drive signal (drive pulse) is output.
[0023]
Further, the ejection signal generation unit 200 receives the encoder pulse and outputs a multiplied data transfer start signal for starting the transfer of ejection data to the recording head 5 to the ejection data generation unit 400. Upon receiving this data transfer start signal, the discharge data generation unit 400 reads out image data from the image memory 500 serving as image data storage means in a predetermined arrangement order under the control of the processor 100, and discharge data (drive pulse on / off). Signal) to the recording head 5. The recording head 5 is driven based on the driving pulse and the ejection data, and ejects ink toward the recording medium 1.
[0024]
Here, the configuration of the ejection signal generator 200 will be described in more detail with reference to FIG.
[0025]
In the figure, reference numeral 201 denotes a discharge reference signal generation unit (signal generation means) including a multiplication circuit that receives an input encoder pulse and multiplies it to generate an output pulse (discharge reference signal). The ejection reference signal generation unit 201 is controlled in response to the start command of the processor 100, and multiplies the encoder pulse to raise the multiplied pulse as shown in (1) of FIG. The number of multiplications here can be arbitrarily set, such as 2 times or 4 times.
[0026]
This ejection reference signal becomes a data transfer start signal for transferring ejection data to the recording head 5, and is output to the AND circuit 202 at the same time as being output to the ejection data generation unit 400 shown in FIG. 2.
[0027]
Further, the ejection reference signal generated by the ejection reference signal generation unit 201 is also output to the pattern selection counter 203. The ejection signal generation unit 200 also functions as a thinning pattern storage unit in the present invention, and stores a 4-bit ejection signal generation pattern value 204 written by the processor 100. The pattern selection counter 203 outputs a thinning pattern selection signal based on the ejection reference signal to the ejection pattern selector 205 that selects any ejection pattern from the ejection signal generation pattern value 204.
[0028]
A signal when the selected discharge pattern value “0001” is selected from the discharge signal generation pattern value 204 in the discharge pattern selector 205 is indicated by (2) in FIG. When “1”, the signal is on (rising), and when “0”, the signal is off. Thus, when the pattern value is “0001”, “1”, “0”, “0”, and “0” from the right of the pattern value, and therefore, one on (rising) signal and 3 are synchronized with the ejection reference signal. It becomes a signal which repeats this after one off signal. Thus, the ejection pattern selector 205 constitutes a timing control means for controlling the ejection signal start timing by the selected thinning pattern.
[0029]
The selected ejection pattern value output from the ejection pattern selector 205 is output to the AND circuit 202. The AND circuit 202 takes an AND of the discharge reference signal ((1) in FIG. 5) from the discharge reference signal generation unit 201 and the signal ((2) in FIG. 5) based on the selected discharge pattern value, and outputs this AND output. Output as a discharge signal. This is indicated by (3) in FIG. As a result, a discharge signal in which a predetermined number is thinned out is generated.
[0030]
The thinning pattern at this time can be appropriately changed by selecting a pattern value set in the ejection signal generation pattern value 204. For example, when the selected discharge pattern value “0010” is selected from the discharge signal generation pattern value 204 in the discharge pattern selector 205, “0”, “1”, “0”, and “0” from the right of the pattern value. Is as indicated by (2) in FIG. 5, and the ejection signal output from the AND circuit 202 is as indicated by (3) in FIG. This is a signal in which the start timing of the discharge signal is shifted by one discharge reference signal with respect to (2) and (3) in FIG.
[0031]
The recording head 5 repeats reciprocating movement along the main scanning direction, and records an image by landing ink at the same position at the time of both forward and backward. May not land at the same position. In such a case, by controlling the discharge signal start timing by changing the thinning pattern by selecting the pattern value set in the discharge signal generation pattern value 204, the ink can be used both when the recording head 5 moves forward and when it returns. Can be corrected so that they land at the same position.
[0032]
Next, the configuration of the ejection data generation unit 400 will be described in more detail with reference to FIG.
[0033]
In the ejection data generation unit 400, the image data development unit 401 reads the image data from the image memory 500 illustrated in FIG. 2 and takes the developed image data into the development memory 402 under the control of the processor 100. The image data once taken into the development memory 402 is read again and written into the buffer memory 403.
[0034]
At this time, the image data is written in the buffer memory 403 in units of one line in the main scanning direction (left and right direction in FIG. 6) shown in FIG. FIG. 6 shows image data for 8 × 8 pixels in which the main scanning direction is 8 pixels and the number of nozzles is 8.
[0035]
The ejection data thinning unit 404 reads out the image data from the buffer memory 403 and rearranges the data as follows. That is, data for eight pixels in the uppermost main scanning direction shown in FIG. 6 is read from the buffer memory 403, and data of one pixel at any one of the positions is first output to the recording head 5 as ejection data. .
[0036]
The discharge data generation unit 400 includes a thinning step register (thinning step storage unit) 407a, a discharge data transfer start position register (start pixel storage unit) 407b, and a register selection unit (discharge data) including a nozzle number and head number information storage unit 407c. Selection means) 407 is provided. The discharge data transfer start position register (start pixel storage means) 407b stores start pixel information (offset) that is a position of a pixel from which thinning is started. Of the data for eight pixels in the main scanning direction, The register selection unit 407 selects which pixel at which position to take out based on the ejection data transfer start position register 407b. For example, as shown in FIG. 7, when offset is “0”, the start pixel is the first pixel, and when “1”, the start pixel is the second pixel, “2” indicates that the start pixel is the third pixel, and “3” indicates that the start pixel is the fourth pixel.
[0037]
Next, the ejection data thinning-out unit 404 reads out the data for 8 pixels in the main scanning direction in the lower stage from the buffer memory 403, and outputs the pixels to the recording head 5 out of the data for 8 pixels in the upper stage. Is output to the recording head 5 as ejection data.
[0038]
By repeating this for the number of nozzles, image data for one vertical column in FIG. 6 is output to the recording head 5 as ejection data. The information on the number of nozzles is stored in the nozzle number and head number information storage unit 407c and is counted by the nozzle number counter 405.
[0039]
The thinning step register 407a stores the number (hstep) of counting the data transfer start signal (discharge reference signal) output from the discharge signal generator 200 and jumping in the horizontal direction (main scanning direction). In this embodiment, hstep indicates the case of quadruple interleaving stored from “1” to “4” as shown in FIG. 7, where “1” does not perform skipping, that is, does not perform decimation. "2" is a case where data is output by thinning out every other pixel, "3" is a case where data is output by thinning out every two pixels, and "4" is data thinned out every third pixel. Each case of output is shown. In FIG. 7, a pixel from which “◯” is read and a pixel from which “×” is not read are shown, and the horizontal numerical value at the top indicates the number of pixels in the horizontal direction.
[0040]
As described above, when the image data for one vertical column shown in FIG. 6 is output to the recording head 5 as ejection data, the ejection data thinning unit 404 then thins out pixels in accordance with the specified value of hstep. Output to the recording head 5 as ejection data. For example, in the case of hstep = 2, since data output is performed by thinning out every other pixel, one pixel in the main scanning direction is skipped from the position where the image data for one vertical column is output to the recording head 5 as ejection data. The image data for one vertical column is output as ejection data to the recording head 5 with respect to the pixels in the next column, and thereafter, the vertical column for the pixels in the column further skipped by one pixel in the main scanning direction from that position. The image data for the minute is output to the recording head 5 as ejection data. Information in the main scanning direction is stored in the nozzle number and head number information storage unit 407c and is counted by the main scanning direction counter 406.
[0041]
As a result, a predetermined number of image data is thinned out and output to the recording head 5 as thinned discharge data, so that image data is not output to the recording head 5 unnecessarily. The transfer time can be shortened.
[0042]
【The invention's effect】
According to the present invention, it is possible to provide an ink jet recording apparatus that can eliminate waste of data transfer to the recording head and can shorten the data transfer time.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an example of an inkjet recording apparatus. FIG. 2 is a block diagram illustrating an outline of a drive unit of the inkjet recording apparatus. FIG. 3 is a block diagram illustrating a configuration of an ejection signal generation unit. FIG. 5 is a block diagram illustrating a configuration of a generation unit. FIG. 5 is a timing chart illustrating a signal generation operation of an ejection signal generation unit. FIG. 6 is an explanatory diagram illustrating a method of writing image data. Figure explaining position [Explanation of symbols]
1: recording medium 2a: transport roller 2b: driven roller 3: driving mechanism 4: rotating shaft 5: recording head 6: carriage 7: driving motor 8: scanning belt 9: driving pulley 10: driven pulley 11: driving shaft 12: scanning Guide 100: Processor 200: Ejection signal generation unit 300: Printhead drive circuit unit 400: Ejection data generation unit 500: Image memory

Claims (2)

An image is recorded by scanning a recording head in which a plurality of nozzles are arranged in a main scanning direction that intersects the conveyance direction of the recording medium, and ejecting ink from the nozzles at a predetermined timing based on ejection signals and ejection data. An ink jet recording apparatus for performing
Image data storage means for storing image data;
Signal generating means for generating a data transfer start signal to the recording head;
A thinning pattern storage unit that stores a thinning pattern for thinning out pixels in the main scanning direction, and a timing control unit that controls a start timing at which the ejection signal is turned on / off by a thinning pattern selected from the thinning pattern storage unit. by performing the thinning on the basis of the thinning pattern which has previously been selected for the data transfer start signal, a first thinning means for generating the discharge signal decimated,
Pixels for thinning out pixel data of lines in the main scanning direction of the image data based on a preset thinning number for the image data stored in the image data storage means in accordance with the data transfer start signal Ink jet recording apparatus comprising: a second thinning unit that generates the thinned discharge data by skipping data and outputs only the thinned discharge data to the recording head . The second thinning means includes a thinning step storage means for storing a thinning step, a start pixel storage means for storing a position of a pixel to start thinning, and each information of the thinning step storage means and the start pixel storage means. based on, the ink jet recording apparatus according to claim 1, characterized in that it has a discharge data selection means for selecting data to be transferred to the recording head.

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