JP2008183742A - Apparatus and method for ink jet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To alleviate strike position deviation which may take place when using an inkjet recording apparatus of a drive system in which a plurality of outlet ports is divided into a plurality of blocks. <P>SOLUTION: Recording data for one column of a recording head is stored, and the stored recording data is divided for each block. The record data for each block is used to calculate the dot number for recording with ink discharge in each block. The recording data for each block from which the dot number is calculated is stored, and the drive order of each block is changed based on the calculated dot number of each block so that a block having a larger dot number may become close in drive order. In accordance with the changed drive order, a block-specifying signal which specifies the block to be driven and the block recording data corresponding to the block-specifying signal stored in the second memory means are successively transmitted to the recording head. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method for recording an image on a recording medium by dividing the plurality of recording elements in a recording head having a plurality of recording elements into a plurality of blocks and performing time-division driving for each block. About.

  An ink jet recording apparatus (ink jet recording apparatus) is designed to increase the recording speed by increasing the number of recording elements of the recording head and shortening the drive cycle of the recording head. In such a recording apparatus, when all the recording elements are driven simultaneously, the power consumption temporarily increases, which is disadvantageous in securing the power supply capacity.

As a countermeasure, there is a method of averaging power consumption by adopting a block driving method in which a plurality of recording elements are divided into a plurality of blocks and time-division driven for each block (for example, see Patent Document 1). In this block driving method, the recording elements for each divided block are time-division driven in a fixed order. When all the blocks are driven once, all the printing elements are driven. In a serial type recording apparatus, such driving is repeated while the recording head performs one scan.
Japanese Patent Laid-Open No. 5-220988 (page 5, FIG. 1)

  However, in the block driving method, the recording head moves in the scanning direction until the driving of all the blocks is completed. For this reason, the ink landing positions on the recording medium from the recording elements (nozzles) of different driving blocks are shifted by the amount of movement of the recording head corresponding to the shift of the driving timing between the blocks. FIG. 2 is a schematic diagram showing the landing position deviation of ink when an image is formed using a recording head that performs time-division driving for each block. In FIG. 2, images are recorded by sequentially driving from block 1 to block 8. As is apparent from this figure, the landing position from the nozzle of block 1 to the landing position from the nozzle of block 8. The landing position gradually shifts until. In the conventional block drive type ink jet recording apparatus, there is a case where such landing position misalignment becomes a problem.

  Accordingly, the present invention is to solve the above-described problems, and provides an ink jet recording apparatus and an ink jet recording method that alleviate landing position deviation in a block drive type ink jet recording apparatus.

In order to solve the above problems, the present invention reciprocates a recording head in which a plurality of recording elements are arranged in a line and the recording elements are divided into a plurality of blocks in a direction perpendicular to the arrangement direction of the recording elements. An inkjet recording apparatus that performs recording by time-division driving in units of blocks,
First storage means for storing recording data for one column of the recording head;
Counting means for dividing the recording data stored in the first storage means into the plurality of blocks and counting the number of dots to be recorded with ink ejection in each block from the recording data for each block;
Second storage means for storing recording data for each block in which the number of dots is counted by the counting means;
Based on the number of dots of each block counted by the counting means, changing means for changing the drive order of each block so that the block having a large number of dots is in a close drive order;
In accordance with the drive order changed by the changing means, a block specifying signal for specifying a block to be driven and print data of a block corresponding to the block specifying signal stored in the second storage means are sequentially supplied to the print head. A transfer means for transferring;
An ink jet recording apparatus characterized by comprising:

In another aspect of the present invention for solving the above-described problem, a recording head in which a plurality of recording elements are arranged in a line and the recording elements are divided into a plurality of blocks is arranged in a direction perpendicular to the arrangement direction of the recording elements. An ink jet recording method for performing time-division drive recording in units of blocks while reciprocally moving to
A first storage step of storing recording data for one column of the recording head in a first buffer;
A counting step of dividing the recording data stored in the first buffer into the plurality of blocks and counting the number of dots to be recorded with ink ejection in each block from the recording data of each block;
A second storage step of storing the recording data for each block in which the number of dots is counted in the counting step in a second buffer;
Based on the number of dots of each block counted in the counting step, a changing step of changing the drive order of each block so that the block having a large number of dots is in a close drive order;
In accordance with the driving order changed in the changing step, a block specifying signal for specifying a block to be driven and recording data of a block corresponding to the block specifying signal stored in the second buffer are sequentially transferred to the recording head. A transfer process to
It is an inkjet recording method characterized by having.

  According to the present invention, the driving order of each block is rearranged according to the number of recording dots of each block, and the block having a large number of recording dots is set to a near driving order, thereby landing on the recording medium by the movement of the recording head. Misalignment can be mitigated.

  Embodiments of the present invention will be described below with reference to the drawings.

  In this specification, “recording” not only forms significant information such as characters and graphics, but also forms images, patterns, patterns, etc. on a wide variety of recording media, regardless of significance, or It also represents the case where the medium is processed. It does not matter whether it has been made obvious so that humans can perceive it visually.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  The term “ink” should be broadly interpreted in the same way as the definition of “recording”. When applied to a recording medium, the “ink” forms an image, a pattern, a pattern, or the like, or processes the recording medium. It represents a liquid that can be subjected to the treatment. Examples of the ink treatment include solidification or insolubilization of the colorant in the ink applied to the recording medium.

<Outline of the present invention>
The present invention alleviates landing position misalignment in a block drive type ink jet recording apparatus that performs recording by time-division driving in units of blocks, and changes the drive order of blocks based on the number of dots to be recorded in each block. It is characterized by doing. FIG. 1 is a schematic diagram comparing landing position deviations during image formation in a conventional block driving type ink jet recording apparatus and a block driving type ink jet recording apparatus of the present invention. FIG. 1A shows a conventional landing position deviation, and FIG. 1B shows an example of the landing position deviation of the present invention. The dots on the same line in the figure indicate the same block, the black circles in the figure indicate dots that are recorded with ink ejection, the white circles indicate dots that are not recorded, and the numbers in the figure are each The number of dots (black circles) on which recording is performed in the block is shown. In FIG. 1B, blocks having a large number of dots that have been recorded are continuously recorded, so that it is possible to form an image in which the influence of the landing position deviation is mitigated compared to FIG.

(1) Description of Inkjet Recording Apparatus FIG. 3 is a schematic perspective view showing the configuration of an embodiment of a color inkjet recording apparatus (hereinafter referred to as a recording apparatus) to which the present invention can be applied. In this figure, 201 is a recording head, and a plurality of recording elements are arranged in a line. Reference numeral 202 denotes an ink cartridge. These are composed of ink tanks each containing four color inks (black, cyan, magenta, yellow). Reference numeral 103 denotes a paper feed roller that rotates in the direction of the arrow in the figure while holding the recording medium 107 together with the auxiliary roller 104 to feed the recording medium 107. Reference numeral 106 denotes a carriage, which moves the four ink cartridges 202 and the recording head 201 to be mounted together with recording. The carriage 106 is controlled so as to stand by at the home position indicated by the dotted line in the drawing when the recording apparatus is not performing recording or when the recovery operation of the recording head is performed.

  Prior to the start of recording, the carriage 106 positioned at the position (home position) in the figure moves in the X direction orthogonal to the arrangement direction of the recording elements when a recording start command is received. In this way, the recording apparatus drives the recording element provided in the recording head 201 to perform recording in an area corresponding to the recording width of the recording head on the recording medium. When recording to the edge of the recording medium is completed along the scanning direction of the carriage 106, the carriage 106 returns to the original home position, and the recording apparatus performs recording while moving the carriage 106 in the X direction again. The paper feed roller 103 rotates in the direction of the arrow shown in the drawing after the previous print scan is finished and before the next print scan is started to feed the paper in the Y direction by the required width. In this way, the recording on one recording medium is completed by repeating the scanning of the carriage 106 for recording and the paper feeding. A recording operation for ejecting ink from the recording head is performed based on control from a recording control means (not shown).

  Further, in order to increase the recording speed, the recording is not performed only when scanning in one direction, but is performed also in the backward scanning when the carriage is returned to the home position side after the recording in the forward scanning in the X direction is finished. It may be.

  In the example described above, the ink tank and the recording head are held on the carriage 106 so as to be separable. An ink jet cartridge in which an ink tank that stores recording ink and a recording head 201 that discharges ink toward the recording medium 107 are integrated may be used. Furthermore, a multi-color integrated recording head that can eject a plurality of colors of ink from one recording head may be used.

  Further, a capping unit (not shown) that caps the ejection port surface of the recording head is provided at a position where the above recovery operation is performed. In addition, a recovery unit (not shown) that performs a recovery operation of the recording head, such as removing thickened ink and bubbles in the recording head in a cap state by the capping means, is provided. Further, a cleaning blade (not shown) or the like is provided on the side of the capping unit, and the cleaning blade is supported so as to protrude toward the recording head 201, and can come into contact with the discharge port surface of the recording head. ing. Thus, after the recovery operation, the cleaning blade is projected into the moving path of the recording head, and unnecessary ink droplets and dirt on the front surface of the recording head are wiped off as the recording head moves.

(2) Description of Recording Head Next, the above-described recording head 201 will be described with reference to FIG. 4 is a perspective view of a main part of the recording head 201 shown in FIG. As shown in FIG. 4, the recording head 201 has a plurality of discharge ports 300 each formed at a predetermined pitch, and along the wall surface of each liquid passage 302 that connects the common liquid chamber 301 and each discharge port 300. A recording element 303 for generating ink ejection energy is provided. The recording element 303 and its circuit are made on silicon using semiconductor manufacturing technology. Further, a temperature sensor (not shown) and a sub-heater (not shown) are collectively formed on the same silicon by the same process as the semiconductor manufacturing process. A silicon plate 308 on which these electrical wirings are made is bonded to a heat radiating aluminum base plate 307. In addition, the circuit connection portion 311 on the silicon plate and the printed board 309 are connected by an extra fine wire 310, and a signal from the recording apparatus main body is received through the signal circuit 312. The liquid passage 302 and the common liquid chamber 301 are formed by a plastic cover 306 made by injection molding. The common liquid chamber 301 is connected via the ink tank, the joint pipe 304, and the ink filter 305, and ink is supplied to the common liquid chamber 301 from the ink tank. The ink supplied from the ink tank to the common liquid chamber 301 and temporarily stored enters the liquid path 302 by capillary action and forms a meniscus at the discharge port 300 to keep the liquid path 302 filled. At this time, when the recording element 303 is energized through the electrodes (not shown) and generates heat, the ink on the recording element 303 is rapidly heated to generate bubbles in the liquid path 302, and the bubbles expand to discharge ports. Ink droplets 313 are ejected from 300.

(3) Description of Control Configuration Next, a control configuration for executing recording control of each part of the recording apparatus will be described with reference to a block diagram shown in FIG. In the figure showing the control circuit, a CPU 501 executes control processing of the operation of the recording apparatus, data processing, and the like. The ROM 502 stores programs such as those processing procedures, and the RAM 503 as a storage unit of the present invention or a part of the storage unit of the present invention is used as a work area for executing these processes. Ink is ejected from the print head 201 by the CPU 501 supplying print data and drive signals to the head driver 504. The CPU 501 controls a carriage motor (CR motor) 507 for driving the carriage 106 in the main scanning direction via a motor driver 506, and a motor driver 508 for an LF motor 509 for conveying a recording medium in the sub scanning direction. Control through.

(4) Description of Gate Array Next, recording data generation in the control configuration will be described mainly with reference to the block diagram shown in FIG.

  Reference numeral 601 denotes a block for receiving data taken into the gate array by a data receiving block. Reference numeral 602 denotes a data analysis / decompression block that extracts recording data from received data. Reference numeral 603 denotes a first buffer, which stores this recording data as raster data. The raster data is stored for each color, and in subsequent block processing, the raster data is processed in time series for each color of Bk, C, M, and Y. The raster data stored in the first buffer 603 is subjected to column conversion in the raster-column conversion block 604 and stored as column data in the second buffer 605. At this time, the number of recording dots is counted (counted) from the column data after column conversion, and the dot count value is stored in the third buffer 606. The timing generation block 607 outputs the timing for generating print data in synchronization with the carriage motor 507 to the column data extraction block 608, the data expansion / extraction block 609, and the print data transfer block 611.

  The column data extraction block 608 reads the column data stored in the second buffer 605 based on the recording data generation timing generated by the timing generation block 607, and performs recording data extraction and mask processing. Next, in the data expansion / extraction block 609, the index data of the recording data for one column of the recording head 201 is expanded, and the recording data for each block is extracted and stored in the fourth buffer 610. Next, in the recording data transfer block 611, the recording data extracted from the fourth buffer 610 is read based on the recording data generation timing generated by the timing generation block 607 and sequentially transferred to the recording head 201.

(5) Description of Print Head Control FIG. 7 is a configuration diagram of a drive circuit that drives the print head 201. FIG. 8 is a timing chart for explaining the drive timing. As shown in FIG. 7, the recording head 201 has 64 recording elements divided into 8 by 8 by an 8-bit shift register 703 and three block division signals (BE0, BE1, BE2). Yes. When the heater 701 as a recording element is heated, film boiling occurs in the ink, and the ink can be ejected.

  As shown in FIG. 8, the recording data is serially transferred from the host to the shift register 703 using the clock signal (HCLK) and the recording signal (Si), and latched in the latch 702 by the latch signal (BG). Is done. The block division signal (BE0, BE1, BE2) is decoded into eight signals by the decoder 700, and becomes an enable signal (block designation signal) for each of the eight-divided heaters 701. Then, ejection control is performed in accordance with the calculation result of the logical product of the recording signal, the block designation signal for designating the block, and the heat pulse signal (HE).

  Next, an embodiment of a method for reducing the landing position deviation in the recording apparatus having the above configuration will be described.

(Example 1)
FIG. 9 is a block diagram for generating recording data. FIG. 9 shows the data development / extraction block 609, the fourth buffer 610, which is an HSRAM, and the recording data transfer block 611.

  The recording data 902 for each block is extracted from the recording data 901 for one column of the recording head 201 in the driving order of each block, and is temporarily stored in the fourth buffer 610. The number of recording dots in each block is counted from the recording data 902 for each block extracted at this time. Hereinafter, the count value is referred to as a dot count value 903. Using this dot count value 903, the drive order of each block is changed by a method described later and stored in the dot count comparison register 904.

  The dot count comparison register 904 stores a dot count value 906, an address 907 where the data is stored, and flag information 905 for confirming the presence or absence of the dot count for one column.

  The recording data transfer block 611 sequentially reads the recording data 908 stored in the fourth buffer 610 in accordance with the transfer timing input from the timing generation block 607 described above. Note that the recording data 908 corresponding to the address 907 is sequentially read out in the drive order of each block stored in the dot count comparison register 904 described above. Then, transfer 909 of the recording data to the recording head is sequentially performed.

  Next, the rearrangement method of the drive order of each block is demonstrated using the flowchart of FIG.

  Here, first, it is assumed that the dot count comparison register 904 stores dot count values and their address information in the order of “DOT_reg (α), DOT_reg (α−1)... DOT_reg (0)”. .

  First, in step S110, the number of recording dots of the recording data 902 for each block in the block to be rearranged in the driving order stored in the fourth buffer 610 is counted. Next, in step S120, a number that becomes “the total number of blocks−1” is substituted into α. In this embodiment, since the total number of blocks is “8”, α is “7”. Next, in step S130, it is confirmed whether or not there is data in DOT_reg (α) of the dot count comparison register 904.

  If there is no data in step S130, the dot count value counted in step S110 and its address information are substituted into DOT_reg (α) in step S170, and the process ends.

  If there is data in step S130, the dot count value of DOT_reg (α) is compared with the dot count value obtained in step S110 in step S140. If the dot count value DOT_reg (α) of the dot count comparison register 904 is larger, α−1 is set to α in step S150, and if α is not “0”, the process returns to step S140 by step S160. If α is “0”, in step S170, the dot count value counted in step S110 and its address information are substituted into DOT_reg (α), and the process ends.

  In step S140, if the dot count value obtained by counting in step S110 is larger, in step S180, the value of DOT_reg (α) is substituted into DOT_reg (α-1), and in the same way up to DOT_reg (0). Replace each other. Thereafter, in step S170, the dot count value counted in step S110 and its address information are substituted into DOT_reg (α), and the process is terminated.

  In this way, by updating the dot count value 903 of all blocks according to this flowchart, the dot count value and its address information are stored in the dot count comparison register 904 in descending order of the dot count value. Is done.

  In this embodiment, the dot count comparison register 904 rearranged in the order of the blocks having the largest dot count value is used to perform bidirectional printing so that the block is driven from the block having the largest dot count value in both the forward pass and the return pass. . More specifically, recording is performed by transferring the print data to the print head in the order of the dot count comparison register in the forward path and in the reverse order in the reverse path in accordance with the signal for determining the forward or backward path of the carriage received from the timing generation block 607. .

  In this embodiment, the driving order of the blocks is rearranged in descending order of the dot count value, but can be rearranged in ascending order.

(Example 2)
In Example 1, the driving order of each block was rearranged in descending order of the dot count value.

  In this embodiment, a block with a small number of recording elements to which ink is ejected is set as the first and last driving order in one cycle of time-division driving, and a block with a large number of recording elements to which ink is ejected is time-division driven. An intermediate driving order in one cycle was used. The remaining blocks are arranged in a driving order in which the number of recording elements on which ink is ejected is gradually reduced from the intermediate driving order block to the first and last driving order blocks. Using the dot count comparison register 904 with the drive order changed in this way, recording was performed in both forward and backward directions.

  FIG. 11 is a schematic diagram showing the dot count amount from each block recorded when the recording head reciprocates for Example 1 and Example 2. FIG.

(Example 3)
In the present embodiment, the dot count comparison register 904 of the first embodiment is used so that the recording order of each block in the forward path and the backward path can be changed from the order in which the dot count value is large or small. We recorded in the direction. More specifically, it is possible to change whether the recording data is transferred to the recording head in the order of the dot count comparison register or the reverse order in the forward path or the backward path.

It is the model which compared the landing position shift | offset | difference at the time of image formation in the conventional and the block drive type inkjet recording device of this invention. FIG. 6 is a schematic diagram illustrating an ink landing position shift when an image is formed using a block-driven recording head. 1 is a schematic perspective view showing a configuration of an embodiment of a color inkjet recording apparatus to which the present invention can be applied. FIG. 3 is a perspective view of a main part of the recording head. FIG. 3 is a block diagram illustrating a control configuration for executing recording control of each unit of the recording apparatus. It is a block diagram which shows the gate array in connection with recording data generation and control in a control structure. FIG. 3 is a configuration diagram of a drive circuit that drives a recording head. FIG. 3 is a diagram illustrating a drive timing chart of a recording head. It is a block diagram of a discharge order change part at the time of generating record data. It is a flowchart which shows the rearrangement method of the drive order of each block. FIG. 6 is a schematic diagram showing dot count amounts from each block recorded when the recording head in Example 1 and Example 2 reciprocates.

Explanation of symbols

201 recording head 303 recording element 501 CPU
503 RAM

Claims (6)

A recording head in which a plurality of recording elements are arranged in a line and the recording elements are divided into a plurality of blocks is driven by time-division driving in units of the blocks while reciprocating in a direction perpendicular to the arrangement direction of the recording elements. An ink jet recording apparatus for performing
First storage means for storing recording data for one column of the recording head;
Counting means for dividing the recording data stored in the first storage means into the plurality of blocks and counting the number of dots to be recorded with ink ejection in each block from the recording data for each block;
Second storage means for storing recording data for each block in which the number of dots is counted by the counting means;
Based on the number of dots of each block counted by the counting means, changing means for changing the drive order of each block so that the block having a large number of dots is in a close drive order;
In accordance with the drive order changed by the changing means, a block specifying signal for specifying a block to be driven and print data of a block corresponding to the block specifying signal stored in the second storage means are sequentially supplied to the print head. A transfer means for transferring;
An ink jet recording apparatus comprising:   2. The ink jet recording apparatus according to claim 1, wherein the changing unit changes the driving order so as to drive from a block having a large number of recording elements on which ink is discharged.   2. The ink jet recording apparatus according to claim 1, wherein the changing unit changes the driving order so as to drive from a block having a small number of recording elements on which ink is discharged.   The changing means sets a block having a small number of recording elements to be ejected ink as the first and last driving order in one cycle of time-division driving, and a block having a large number of recording elements to be ejected is time-division driven. An intermediate driving order in one cycle is used, and the number of printing elements on which ink is ejected from the intermediate driving order block to the first and last driving order blocks is reduced step by step. 2. The ink jet recording apparatus according to claim 1, wherein the driving order is changed so as to be the arranged driving order.   The inkjet recording apparatus according to claim 1, wherein the changing unit changes a driving order of each block according to a moving direction of the recording head. A recording head in which a plurality of recording elements are arranged in a line and the recording elements are divided into a plurality of blocks is driven by time-division driving in units of the blocks while reciprocating in a direction perpendicular to the arrangement direction of the recording elements. An inkjet recording method for performing
A first storage step of storing recording data for one column of the recording head in a first buffer;
A counting step of dividing the recording data stored in the first buffer into the plurality of blocks and counting the number of dots to be recorded with ink ejection in each block from the recording data of each block;
A second storage step of storing the recording data for each block in which the number of dots is counted in the counting step in a second buffer;
Based on the number of dots of each block counted in the counting step, a changing step of changing the drive order of each block so that the block having a large number of dots is in a close drive order;
In accordance with the driving order changed in the changing step, a block specifying signal for specifying a block to be driven and recording data of a block corresponding to the block specifying signal stored in the second buffer are sequentially transferred to the recording head. A transfer process to
An ink jet recording method comprising:

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