JP4185738B2 - Inkjet recording apparatus and inkjet recording method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus and an ink jet recording method, and more particularly to an ink jet recording apparatus and an ink jet recording method for performing preliminary ejection control.
[0002]
[Prior art]
The ink jet recording apparatus ejects ink as droplets from a plurality of nozzles arranged in a recording head, and records an image with dots formed on a recording medium. In recent years, it has rapidly spread due to the advantage that color recording can be easily performed.
[0003]
If the nozzles arranged in the recording head of the ink jet recording apparatus are left in a state where ink is not discharged for a long time, the ink collected in the vicinity of the discharge port may be hardened. When the ink is solidified, in the next ejection operation, the ink is not ejected, and the image is lost. Even if the ink does not reach a fixed state, dust is deposited near the discharge port, or the ink in the nozzle is thickened, so that an appropriate amount of ink is not discharged in the correct direction, and the formed image May be disturbed. Conventionally, various recovery processes have been performed in order to make a recording head in a state unsuitable for such an ejection operation suitable. For example, pre-discharge or pre-recording at a predetermined position before recording to discharge the thickened ink in the nozzles, or cover the nozzle surface with a cap and suck it. Among these, the preliminary ejection process is performed at regular intervals even during the recording operation.
[0004]
In a serial type recording apparatus in which a recording head scans a recording medium and performs recording, a preliminary discharge port is provided in advance in a place other than the recording area, and the recording head moves here to perform discharge operation several times. .
[0005]
FIG. 15 is a schematic diagram showing a scan pattern in a conventional serial type recording apparatus.
[0006]
The recording head H moves in the forward direction from the recording start position S1 and starts an ejection operation to record the recording portion D1 in one scan. Then, when it moves to the end S2 of the recording area, it moves to the preliminary ejection port PJ2 as it is and performs preliminary ejection. At this time, the paper is fed by the width of the recording head H. When the preliminary ejection is completed, the recording head H moves in the backward direction and records the recording portion D2. Further, the preliminary ejection is performed by moving to the preliminary ejection port PJ1. When a predetermined amount of paper is fed, it moves again in the forward direction and records in the recording unit D3.
[0007]
As described above, in the conventional recording method, for example, every time one scan recording is performed, the recording head moves to a predetermined preliminary discharge port to perform preliminary discharge. It is possible to control the number of preliminary ejections by detecting the amount of recording in one scan and detecting the nozzles used for recording, but in order to perform this control, the load of storing the recording status It is difficult to implement a device suitable for this processing. Therefore, generally, as described above, regardless of the use / non-use of nozzles and the amount of recording, the control that the recording head moves to the preliminary discharge port to perform preliminary discharge after recording for a certain time or constant scan. It has become.
[0008]
By the way, in recent years, there has been provided a recording apparatus that improves image quality by minimizing dots formed on a recording medium. The dots formed by such a recording apparatus have become small enough to be indistinguishable with the naked eye, and further reduction in diameter is expected in the future. In order to form such a small-diameter dot, the discharge port itself is reduced in diameter, and the amount of discharge per one time becomes very small. As described above, ink ejection is affected. Therefore, more frequent preliminary discharge processing is required.
[0009]
[Problems to be solved by the invention]
As described above, the conventional preliminary ejection is performed by moving the recording head at predetermined intervals to a predetermined preliminary ejection port other than the recording area. Therefore, the movement from the recording area to the preliminary ejection port and the movement from the preliminary ejection to the recording area are unrelated to actual recording. Further, since such a movement occurs, the total recording time becomes longer than when the preliminary ejection is not performed.
[0010]
In addition, the conventional preliminary ejection control is a control that performs preliminary ejection at regular intervals regardless of the recording amount and the use / non-use of the nozzles, and thus wastes ink.
[0011]
On the other hand, the diameter of dots has been reduced, and even if only one dot is shot on a sheet of paper on which nothing has been recorded, the dot that has been shot is extremely small and cannot be judged with the naked eye. There is no such thing as changing. Therefore, even if several dots are ejected in addition to the dots for forming the image in the recordable area on the paper surface, the image quality of the formed image does not deteriorate.
[0012]
Further, as the diameter of the dots is reduced, if the preliminary discharge that needs to be frequently performed is moved to the preliminary discharge port each time, the total recording time becomes further longer.
[0013]
The present invention has been made to solve such a problem, and provides an ink jet recording apparatus and an ink jet recording method in which wasteful recording head movement processing and wasteful ink processing are reduced in the preliminary ejection processing. The purpose is to do.
[0014]
[Means for Solving the Problems]
An inkjet recording apparatus according to the present invention creates recording data for driving each nozzle based on image data in an inkjet recording apparatus that performs recording by discharging ink to a recording medium from a plurality of nozzles arranged in a recording head. Recording data creation means for performing, and preliminary ejection pattern data creation means for creating preliminary ejection pattern data by deleting nozzles used in the recording data from a predetermined preliminary ejection pattern, and the recording data Recording is performed on a recording medium based on actual print data obtained by synthesizing the preliminary ejection pattern data .
[0015]
The inkjet recording method of the present invention is an inkjet recording method in which recording is performed by discharging ink to a recording medium from a plurality of nozzles arranged in a recording head, and recording data for driving the nozzles is generated based on image data. A recording data creation step, a preliminary ejection pattern data creation step of creating preliminary ejection pattern data by deleting nozzles used in the recording data from a predetermined preliminary ejection pattern, the recording data and the preliminary ejection And a recording step of recording on a recording medium based on actual print data obtained by synthesizing the pattern data .
[0016]
According to the above configuration, the preliminary ejection by the preliminary ejection pattern and the recording by the recording data can be simultaneously performed on the recording medium. Therefore, during the recording, the preliminary ejection is performed by moving to the preliminary ejection port every scanning. This eliminates the need to improve the recording throughput. In addition, the nozzle drive data creation means synthesizes the recording data and the preliminary ejection pattern to create nozzle drive data for driving each nozzle, so it is necessary to perform preliminary ejection for the nozzles that are recording. Preliminary discharge can be performed only for a proper nozzle. Therefore, compared to the preliminary ejection that has been performed regardless of whether or not it has been used up to now, waste of ink is eliminated, and the ink consumption can be suppressed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0018]
FIG. 1 is a perspective view showing an ink jet recording apparatus according to an embodiment of the present invention.
[0019]
An ink tank 101 is connected to the recording head 102 and supplies ink to the recording head 102. There are four ink colors, yellow (Y), magenta (M), cyan (C), and black (K).
[0020]
The recording head 102 has a plurality of ejection openings arranged on the surface facing the recording medium P. The ejection ports are arranged in the arrow Y direction, and the ejection port arrays are arranged in parallel in the arrow X direction for each ink color.
[0021]
A paper feed roller 105 feeds the recording medium P to the recording start position.
[0022]
Reference numeral 106 denotes a carriage which mounts the ink tank 101 and the recording head 102 and performs reciprocating scanning in the direction of arrow X along the guide rail 107. When the carriage 106 is scanned, ink is ejected from the recording head 102 to the recording medium P. When the carriage 106 moves to the other end of the recording medium P, the transport rollers 103 and 104 rotate to transport the recording medium P by a predetermined amount in the arrow Y direction. In this way, recording is performed on the entire recording medium P by alternately repeating recording by the recording head 102 and paper feeding by the transport rollers 103 and 104.
[0023]
h denotes a home position, which is a place where the carriage 106 waits after the recording operation is completed.
[0024]
FIG. 2 is a block diagram showing a recording system including the ink jet recording apparatus according to the embodiment of the present invention.
[0025]
The ink jet recording apparatus 1 is connected to a host computer 2 such as a personal computer by wire or wireless, and can send and receive data to and from each other. When image data created by the user on the host computer 2 is sent to the inkjet recording apparatus 1, the inkjet recording apparatus 1 creates recording data based on the image data and performs recording.
[0026]
The recording head has a plurality of ejection openings arranged as described above. Each ejection port communicates with an ink tank through an ink path, and ink is always filled up to the ejection port. A heating heater, which is an electrothermal converter, is provided corresponding to each discharge port. When the ink is discharged, the heating heater generates heat, and film boiling occurs in the ink. A predetermined amount of ink is ejected by the generation pressure of the bubbles generated by the film boiling. The ink ejection method of the present embodiment is a so-called bubble-through method, but the present invention is not limited to this, and other ink ejection methods such as a piezo method may be used.
[0027]
The amount of ink ejected from each ejection port of the recording head is assumed to be 1 to 2 pl. However, the present invention is not limited to this and may take any value.
[0028]
FIG. 3 is a block diagram showing an electrical configuration of the ink jet recording apparatus.
Reference numeral 300 denotes a CPU that controls the entire inkjet recording apparatus. The CPU 300 includes a ROM 301 and a random memory (RAM) 302. Then, a drive command is sent to each drive unit via the main bus line 305. Further, the main bus line 305 includes software processing means such as an image input unit 303 and an image signal processing unit 304 for inputting image data from the host computer, an operation unit 306, a recovery system control circuit 307, a head drive control circuit 315, Each of hardware processing means such as a carriage drive control circuit 316 in the main scanning direction and a paper feed control circuit 317 in the sub scanning direction can be accessed. A drive control program for head recovery processing is stored in the RAM 302 in advance, and recovery conditions such as preliminary ejection conditions are given to the recovery system control circuit 307, the recording head, the heat retaining heater, and the like as necessary. The recovery system motor 308 drives the recording head 313 and the cleaning blade 309, the cap 310, and the suction pump 311 that face and separate from the recording head 313 as described above. The head drive control circuit 315 executes the drive conditions of the ink ejection electrothermal converter of the recording head 313, and causes the recording head 313 to perform normal preliminary ejection and recording ink ejection.
[0029]
FIG. 4 is a schematic diagram showing a recording operation for each scan in the present embodiment.
[0030]
The recording head 102 moves in the forward direction from the recording start position, and records the area D1. When it moves to the end in the area D1, it stops at that position and waits for the recording medium to be fed. When the paper is fed, it moves in the backward direction to the start position of the area D2, which is the next recording portion, and the area D2 is recorded. Then, when recording is performed up to the end of the area D2, it stops at that position and waits for the recording medium to be fed. Then, the area D3 is recorded. Conventionally, every time one scan recording is performed, the preliminary ejection is performed by moving to the preliminary ejection port provided outside the recording area, but in the present embodiment, the preliminary ejection port is not provided outside the recording area. By performing preliminary ejection in the recording area, the recording throughput is improved.
[0031]
Hereinafter, the preliminary discharge control method in the present embodiment will be described.
[0032]
FIG. 5 is a flowchart showing the flow of processing from image data sent from the host computer until recording is performed.
[0033]
When image data is sent from the host computer to the inkjet recording apparatus, it is once converted into raster format recording data and stored in the reception buffer (step 501). Next, data is developed in the work buffer in units of rasters (step 502). When all the data is expanded on the work buffer side, the reception buffer is released and the newly transmitted image data is stored. On the other hand, the raster format recording data expanded in the work buffer is then converted into column format recording data and expanded in the print buffer (step 503). At this time, the ejection nozzles used in the next scan are detected in parallel during development and stored as preliminary ejection pattern mask information (step 504). At the same time, preliminary discharge pattern information of the scan width to be printed is created (step 506). The preliminary discharge pattern is determined from the preliminary discharge pattern information, the preliminary discharge pattern mask information, and the preliminary discharge pattern offset information (details will be described later). A buffer is created (step 505). The print buffer and the preliminary discharge pattern buffer are overlapped to create actual print data, which is developed in the actual print data buffer (step 507). Then, actual print processing is performed according to the actual print data. At this time, the start position of the preliminary ejection pattern is updated and stored as preliminary ejection pattern offset information (step 508).
[0034]
Next, in the above processing routine, when the recording data is developed in the print buffer in step 503, a method for developing the preliminary ejection pattern information that is simultaneously developed will be described in detail.
[0035]
FIG. 6 shows an image diagram stored in the print buffer in a raster format for one scan.
[0036]
Assume that the recording head has n nozzles in total, and in the same figure, the image data indicates that recording is performed by the fourth to xth nozzles.
[0037]
FIG. 7 is a diagram showing preliminary ejection pattern mask information.
[0038]
Separately from the print data raster-developed from the work buffer to the print buffer, the print data is developed in a column format, and preliminary ejection pattern mask information is created from the nozzles used for printing. In this example, since it is from the 4th to the xth, the preliminary ejection pattern mask information is a continuous dot row from the 4th to the xth.
[0039]
FIG. 8 is a diagram showing preliminary ejection pattern information.
[0040]
Preliminary ejection pattern information is created from the current preliminary ejection offset value (information indicating where in the preliminary ejection pattern for one period starts, details will be described later).
[0041]
The preliminary ejection pattern is determined by masking the preliminary ejection pattern information and the previously obtained preliminary ejection pattern mask information (see FIG. 7). In the case of this example, the preliminary ejection pattern information is evenly scattered from the nozzle 2 to the nozzle n−1. However, since the nozzle 4 to the nozzle x are used for recording an image, it corresponds to that portion. There is no need to perform preliminary discharge. Therefore, this portion of data is deleted.
[0042]
FIG. 9 shows the preliminary ejection pattern information after masking with the preliminary ejection pattern mask information. Thus, the ejection pattern from the nozzle 4 to the nozzle x is deleted. Next, the raster format recording data already stored in the print buffer and the masked preliminary discharge pattern data are overlapped to obtain actual print data to be actually recorded.
[0043]
FIG. 10 is a diagram showing actual print data obtained by synthesizing the recording data of FIG. 6 and the preliminary ejection pattern data of FIG. By storing this in the actual print buffer and executing the printing process, preliminary ejection can be realized on the paper surface. That is, the nozzles that perform recording are omitted because there is no need for preliminary ejection, and only nozzles that are not used for recording are subjected to preliminary ejection. Then, during one scan recording, only the nozzles that are not used for the scan recording perform preliminary ejection together. Accordingly, in addition to the original image, preliminary printing dots are printed in several places in the formed recording result. However, since the dot diameter is very small, even if one dot is scattered alone, the image quality is hardly affected.
[0044]
Next, a method for determining the preliminary ejection pattern information will be described. This changes the preliminary ejection interval from the basic pattern in accordance with the temperature of the recording head, and provides preliminary ejection pattern information suitable for the current state of the recording head.
[0045]
FIG. 11A shows the preliminary ejection reference pattern information stored in advance in the nonvolatile memory.
[0046]
The predischarge reference pattern information table stored in advance indicates the absolute position from the print start position in units of columns for all nozzles when the predischarge pattern cycle is f (n). As shown in FIG. 12A, the preliminary ejection pattern information according to this table is that nozzle No. 1 performs preliminary ejection at the n1 column from the recording start position K, and the nozzle number at the n2 column from the recording start position K. The two nozzles form a pattern for preliminary discharge.
[0047]
However, when the temperature of the recording head is high, the ink in the nozzles is not thickened, so the frequency of preliminary ejection may be less than when the temperature is low. Therefore, wasteful preliminary ejection can be reduced by adjusting the preliminary ejection pattern period according to the temperature of the recording head.
[0048]
FIG. 13 is a table that defines the preliminary ejection interval time for each head temperature. According to this table, the preliminary discharge interval time T is determined according to the head temperature. Further, from the current recording speed V (dot / sec), the period f of the preliminary ejection pattern is determined by the following equation.
f (m) = V × T (m)
Then, the absolute position information of each nozzle is calculated from the ratio of the obtained preliminary ejection pattern table period to the reference preliminary ejection pattern period f (n) to generate the preliminary ejection pattern table having the preliminary ejection pattern period f (m). (See FIG. 11B).
[0049]
Next, in the process of performing printing, in order to perform preliminary ejection at a predetermined time interval, it is necessary to shift the start position of preliminary ejection pattern data for each scan. This is done as follows.
[0050]
First, the recording start position of the first scan after receiving print data is set to zero. In the preliminary ejection pattern buffer, preliminary ejection patterns corresponding to the maximum width that can be printed in one scan are created in accordance with the resolution at that time. Since the absolute position is indicated in units of columns from the preliminary ejection pattern information, when the absolute position is included in the maximum print width from the recording start position, data is set to the corresponding address, that is, data for discharging one dot To.
[0051]
Next, when the preliminary discharge pattern data and the print data are overlapped with each other and the print data is expanded in the actual print buffer, the print width at that time, that is, the value of the column unit obtained by subtracting the print left end position from the print right end position is obtained and the preliminary discharge offset information is obtained. Add to. The initial value of the preliminary discharge offset information is 0.
[0052]
At the next print scan, the absolute position serving as a reference is obtained from this preliminary ejection offset information, and preliminary ejection pattern data is generated from that position. When the preliminary ejection offset information is updated from the left and right end positions of printing, if the preliminary ejection pattern period is exceeded, the reference value is returned to 0 and the table is rotated. As a result, preliminary ejection of each nozzle onto the paper surface can be performed periodically.
[0053]
FIG. 14 is a diagram showing how the preliminary ejection pattern offset changes from 1 scan to 4 scans.
[0054]
In this way, by creating preliminary ejection pattern data, it is possible to preliminarily eject appropriate nozzles in each scan.
[0055]
【The invention's effect】
As described above, since the preliminary ejection can be performed on the recording medium simultaneously with the recording operation by using the present invention, it is not necessary to perform preliminary ejection by moving to the preliminary ejection port for each scan during recording. Throughput can be improved. Furthermore, since preliminary ejection is not performed for the nozzles that perform recording, and preliminary ejection is performed only for the necessary nozzles, compared to preliminary ejection that has been performed regardless of use / non-use so far, Ink waste is eliminated and ink consumption can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a recording system including the ink jet recording apparatus according to the embodiment of the present invention.
FIG. 3 is a block diagram showing an electrical configuration of the ink jet recording apparatus.
FIG. 4 is a schematic diagram illustrating a recording operation for each scan in the present embodiment.
FIG. 5 is a flowchart showing a flow of processing from image data sent from a host computer to recording.
FIG. 6 is an image diagram stored in a print buffer in a raster format for one scan.
FIG. 7 is a diagram showing preliminary ejection pattern mask information.
FIG. 8 is a diagram showing preliminary ejection pattern information.
FIG. 9 is a diagram showing preliminary ejection pattern data after masking with preliminary ejection pattern mask information.
10 is a diagram showing actual print data obtained by synthesizing the print data of FIG. 6 and the preliminary ejection pattern data of FIG. 9;
11A is preliminary ejection reference pattern information stored in advance in a nonvolatile memory, and FIG. 11B is preliminary ejection pattern information obtained by changing the preliminary ejection pattern period from the reference pattern.
FIG. 12 is a diagram illustrating an actual dot arrangement based on preliminary ejection pattern information.
FIG. 13 is a diagram illustrating a relationship between a recording head temperature and a preliminary ejection interval time.
FIG. 14 is a schematic diagram showing a preliminary ejection pattern offset position for each scan.
FIG. 15 is a schematic diagram illustrating a conventional preliminary discharge method.
[Explanation of symbols]
101 Ink Tank 102 Recording Head 103 Conveying Roller 104 Conveying Roller 105 Feeding Roller 106 Carriage 107 Guide Rail 300 CPU
301 ROM
302 RAM
303 Image input unit 304 Image signal processing unit 306 Operation unit 307 Recovery system control circuit 308 Recovery system motor 309 Blade 310 Cap 311 Pump 313 Recording head 315 Head drive control circuit 316 Carriage drive control circuit 317 Paper feed control circuit

Claims (10)

In an inkjet recording apparatus that performs recording by discharging ink to a recording medium from a plurality of nozzles arranged in a recording head,
Recording data creating means for creating recording data for driving each nozzle based on image data;
Preliminary ejection pattern data creating means for creating preliminary ejection pattern data by deleting the nozzles used in the recording data from a predetermined preliminary ejection pattern;
And an ink jet recording apparatus that performs recording on a recording medium based on actual print data obtained by synthesizing the recording data and the preliminary ejection pattern data . The inkjet recording apparatus scans the recording head in a direction different from an arrangement direction of the nozzles, and performs a recording operation of ejecting ink onto the recording medium at the time of the scanning, and the recording medium as a scanning direction of the recording head. By alternately repeating the paper feeding operation of moving a predetermined amount in different directions, the recorded image is completed,
2. The recording data creating unit creates printing data in one scanning unit, and the preliminary ejection pattern data creating unit creates preliminary ejection pattern data in one scanning unit. Inkjet recording apparatus. Preliminary ejection pattern offset information creating means for storing how far the preliminary ejection pattern has been executed in one scan of the recording head and creating preliminary ejection pattern offset information excluding the previously executed portion at the next scanning Prepared,
The preliminary ejection pattern data generating means, based on data from the start of the preliminary ejection pattern indicated by the preliminary ejection pattern offset information creating means, according to claim 2, characterized in that to create the preliminary ejection pattern data Inkjet recording apparatus. The preliminary ejection pattern is for ejecting ink from the nozzles in a predetermined order at regular intervals,
Depending on the temperature and the recording speed of the recording head, according to any one of the claims 1, characterized in that in the preliminary ejection pattern comprises a preliminary ejection interval determining means for determining a discharge gap of the nozzle 3 Inkjet recording apparatus. The ink jet recording apparatus according to claim 4 , wherein the preliminary discharge interval determination unit increases the preliminary discharge interval as the temperature of the recording head increases. In an inkjet recording method for performing recording by discharging ink to a recording medium from a plurality of nozzles arranged in a recording head,
A recording data creation step for creating recording data for driving each nozzle based on image data;
A preliminary discharge pattern data creation step of creating preliminary discharge pattern data by deleting the nozzles used in the recording data from a predetermined preliminary discharge pattern;
A recording step of recording on a recording medium based on actual print data obtained by combining the recording data and the preliminary ejection pattern data;
Ink jet recording method characterized in that it comprises a. The inkjet recording method includes a recording operation in which the recording head is scanned in a direction different from the nozzle arrangement direction, and ink is ejected onto the recording medium during the scanning, and the recording medium is scanned in the scanning direction of the recording head. By alternately repeating the paper feeding operation of moving a predetermined amount in different directions, the recorded image is completed,
The recording data generation process creates the recording data in one scan unit, the preliminary ejection pattern data creation process in claim 6, characterized in that to create the preliminary ejection pattern data in one scan unit The inkjet recording method as described. A preliminary ejection pattern offset information creation step for storing how far the preliminary ejection pattern has been executed in one scan of the recording head, and creating preliminary ejection pattern offset information excluding a portion previously executed at the next scanning;
The preliminary ejection pattern data creation process, according to claim 7, characterized in that the basis of the data from the start of the preliminary ejection pattern shown preliminary ejection pattern offset information creating step creates said preliminary ejection pattern data Inkjet recording method. The preliminary ejection pattern is for ejecting ink from the nozzles in a predetermined order at regular intervals,
Depending on the temperature and the recording speed of the recording head, according to any one of the 6 to claim, characterized in that it comprises a preliminary ejection interval determination step of determining a discharge gap of the nozzle in the pre-discharge pattern 8 Inkjet recording method. The inkjet recording method according to claim 9, wherein the preliminary ejection interval determining step increases the preliminary ejection interval as the temperature of the recording head increases .

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