JP2001328256A - Ink jet printer and its recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a recording method which enables optimum recording even to media easy to bleed or media on surfaces of which ink is easy to remain. SOLUTION: A recording head 1 is constituted of a plurality of ink discharge elements arranged in a medium transfer direction. The medium is transferred by a quantity smaller than an arrangement length of the ink discharge elements. Moreover, all dots are recorded by a plurality of the number of recording times in a horizontal scanning direction to the same scanning part while dots to be recorded by one horizontal scanning are thinned. Further, a density of recording dots by one horizontal scanning is changed stepwise, e.g. sequentially decreased or increased to the medium transfer direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer for thinning out dots to be recorded in the main scanning direction and complementing all dots with a plurality of lines, and a recording method therefor.

[0002]

2. Description of the Related Art Conventionally, a serial type ink jet printer has the following system. That is, a recording head is provided in which a plurality of ink ejection nozzles are arranged at a predetermined pitch in the medium transport direction (sub-scanning direction), and the recording head scans in the main scanning direction orthogonal to the medium transport direction. Thereby, a recording area (hereinafter, referred to as a band) corresponding to the length of the nozzle row by the plurality of nozzles is recorded in one scan, and after one scan is completed, the medium is conveyed by the band width.
In this method, the next printing scan is executed to form an image.

Conventionally, dots recorded in one printing scan are thinned out in the main scanning direction and printed, and the medium transport amount during one printing scan is made smaller than the band width, so that the previous printing scan is performed. In some cases, a recording control method is performed in which a part of the area recorded by thinning out the dots is re-scanned and the dots thinned out in the previous scan are complementarily recorded.

[0004]

However, in the above-described conventional print control system for complementary printing of thinned dots, dot thinning is performed evenly for a plurality of ejection nozzles. The amount of ink applied is almost equal in any area, and when printing a high-density image by performing multiple scans of conventional thinning printing, a print scan is performed on a medium to which a large amount of ink has already been applied. .

For example, in the case where the recording medium is formed only of a base paper having no ink holding layer and the applied ink diffuses and permeates a relatively wide area into the medium (for example, high quality paper). In addition, the application of a large amount of ink causes the medium to bend, and the printing scan is performed in that state, causing a shift in the print dot position, and the deterioration of the print image quality such as contamination due to the contact of the printhead with the medium. there were. This has become remarkable by increasing the recording density in order to improve the image quality of the conventional device.

On the contrary, when the recording medium has an ink holding layer such as an OHP film, but the limit of the holding layer is relatively small, and the ink applied to the surface of the ink holding layer easily remains. Has the following problems. That is, if the amount of ink applied at the end of the ink divided and applied in a plurality of printing scans is large, the amount of ink remaining on the surface of the holding layer also increases, and the ink permeates into the ink holding layer or dries on the medium surface. Image quality such as lack of surface ink due to transfer to a transport mechanism that comes into contact with the image recording surface, such as a transport roller for transporting the media, as well as contamination due to retransfer from the transport mechanism to the medium by transporting the media before These have become more prominent due to the improvement in recording density of the conventional apparatus and the shortening of the medium transport time for improving the recording speed.

[0007]

The present invention employs the following structure to solve the above-mentioned problems. <Structure 1> A head in which a plurality of ink ejection elements are arranged in the medium transport direction is provided, dots to be printed in one main scan are thinned out, and all dots are printed in the same scanning portion by printing in a plurality of main scan directions. A recording method for an ink jet printer, wherein the density of recording dots in one scan is changed stepwise in the medium transport direction.

<Structure 2> In the recording method for an ink jet printer described in Structure 1, the medium is conveyed by an amount shorter than an array length of a plurality of ink ejection elements.

<Structure 3> A head having a plurality of ink ejection elements arranged in the medium conveyance direction is provided, and the arrangement length of the plurality of ink ejection elements is divided into a plurality of blocks so that medium conveyance for each block is performed. In addition, in an ink jet printer that prints out all dots by printing out dots in one main scan and printing out in a plurality of main scanning directions in the same scanning portion, dots to be thinned out in a main scanning direction of each block in a plurality of blocks A mask data storage unit having a plurality of mask data corresponding to the positions, and configured such that the number of dot positions to be thinned out of each mask data is sequentially different in the medium transport direction for each block, and a plurality of mask data are used. And a control unit for controlling the drive of the head so that the recording data for each block gradually increases or decreases according to the type of the medium. Inkjet printer according to claim.

<Structure 4> In the recording method of the ink jet printer according to structure 1 or 2, the position of the recording dot in the main scanning direction is different from an adjacent line in the medium transport direction. .

<Arrangement 5> A head having a plurality of ink ejection elements arranged in the medium conveyance direction is provided, and the arrangement length of the plurality of ink ejection elements is divided into a plurality of blocks, and the medium conveyance for each block is performed. In addition, in an ink jet printer that prints out all dots by printing out dots in one main scan and printing out in a plurality of main scanning directions in the same scanning portion, dots to be thinned out in a main scanning direction of each block in a plurality of blocks A first mask data storage unit having a plurality of mask data corresponding to the positions, and configured so that the number of dot positions to be thinned out for each mask data is sequentially different along the medium transport direction for each block; 1
The number of dot positions to be thinned out is the same as the number of dot positions to be thinned out, and the second mask data storage portion having different dot positions to be thinned out and a plurality of mask data are used, and the print data for each block is gradually increased according to the type of medium. Alternatively, the head drive control is performed so as to decrease gradually, and the drive control of the head is performed using the mask data of the first mask data storage unit and the mask data of the second mask data storage unit alternately line by line along the medium transport direction. An ink jet printer comprising: a control unit for performing an operation.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to specific examples.

FIG. 1 is a conceptual diagram showing a specific example of a recording method of an ink jet printer according to the present invention. Prior to this, the configuration of an apparatus for realizing the recording method of the ink jet printer of the present example is described. Will be described.

<Structure> FIG. 2 is an external view of an apparatus mechanism of an ink jet printer. The illustrated apparatus includes a recording head 1, a carriage 2, an ink tank 3, an SP motor (space motor) 4, and an LF motor (line feed motor).
5, carriage shaft 6, recording medium 7, transport roller 8
Consists of Since these mechanisms have a known configuration, an outline of the operation will be mainly described.

In such a configuration, the carriage 2 on which the recording head 1 is mounted is driven by the SP motor 4 to
Reciprocal scanning is performed along a carriage shaft 6 which is supported in the lateral direction of the apparatus, and ink droplets are ejected onto a recording medium 7 placed at a position facing the recording head 1 to form an image.

The recording medium 7 is fed into the apparatus from the rear of the apparatus, and transport rollers 8 driven by the LF motor 5
Is transported toward the front of the apparatus. The transport rollers 8 are arranged on the upstream and downstream sides of the recording head 1 along the transport direction, and the recording medium 7 is nipped by a pair of rollers arranged so as to contact the front and back surfaces of the medium. Is carried out.

Next, a control mechanism for realizing the recording method of the ink jet printer of this embodiment will be described.

FIG. 3 is a block diagram of a control mechanism in the ink jet printer. The device shown in FIG.
0, data buffer 11, data mask unit 12, raster-column conversion unit 13, line buffer 14, head drive circuit 15, buffer control unit 16, SP motor control unit 1.
7, an LF motor control unit 18, an I / F control unit 19, and an operation panel 20.

The control unit 10 has a built-in CPU, and has a function of controlling the respective units in an integrated manner. The recording data received from the external device is stored in the data buffer 11 by the control unit 10. The data stored in the data buffer 11 is input to the raster-column conversion unit 13 via the data mask unit 12. The data mask unit 12 is a main component of this specific example, and has a function of executing data thinning processing according to print scanning.

The raster-to-column conversion unit 13 stores a predetermined amount of the print data processed by the data mask unit 12, and executes conversion of raster format data into column format data corresponding to the arrangement of the ejection nozzles of the head. I do.

The recording data converted into the column format is 1
The data amount required for scanning is sequentially stored in the line buffer 14 having a memory capacity for storing the data amount. The flow of recording data from the data buffer 11 to the line buffer 14 is synchronized by the control unit 10 with each processing unit.

The SP motor control unit 17 drives the SP motor 4 according to an instruction from the control unit 10 and outputs a head drive timing signal synchronized with the rotation of the SP motor 4 to the buffer control unit 16 and the head drive circuit 15. . Buffer control unit 1 receiving this head drive timing signal
6 sequentially transfers the print data stored in the line buffer 14 to the head drive circuit 15 in synchronization with the timing signal, and the head drive circuit 15 prints a head drive signal for driving the ejection nozzles corresponding to the print data. Output to head 1.

The recording head 1 drives a corresponding discharge nozzle according to the input head drive signal, and discharges ink as droplets. Further, the LF motor control unit 18 conveys the recording medium 7 by rotating the LF motor 5 by an amount corresponding to the specified conveyance amount in accordance with an instruction from the control unit 10.

The I / F control section 19 controls the interface of the present apparatus with a higher-level device, and print data and control commands transferred from the higher-level device are transmitted to the I / F.
The data is input to the control unit 10 via the control unit 19 and the control unit 10
, The processing is appropriately executed. The operation panel 20 is used by an operator to manually set an operation mode of the apparatus, a recording medium selection, and the like.

Next, the nozzle arrangement of the recording head 1 will be described. FIG. 4 is an explanatory diagram showing an example of thinning out recording dots by nozzle position. The recording head 1 of this specific example has 16 nozzles # 1 to # 16 as ejection nozzles as ink ejection elements, and each nozzle has a pitch corresponding to the image recording density (recording density in the medium transport direction). Are arranged in a line along the transport direction of the medium. Each nozzle has 4
Control is performed by dividing each nozzle into four blocks.

Next, the details of the data mask section 12 will be described. FIG. 5 is a configuration diagram of the data mask unit 12. As shown, the data mask unit 12 includes an input buffer 21,
Mask data storage 22, selector 23, arithmetic circuit 28
Consists of

The input buffer 21 is a buffer for holding recording data to be converted. Mask data storage 2
Numeral 2 stores mask data for data calculation for thinning out the print data, so that the mask data corresponding to the divided block by the ejection nozzle position of the print head 1 described above can be individually stored. It has a plurality of storage memories.

That is, the mask data storage section 22 includes a first block mask data memory 24, a second block mask data memory 25, a third block mask data memory 26, and a fourth block mask data memory 27. I have. The selector 23 is a selector for selecting an output from the first to fourth block mask data memories 24 to 27 and outputting the selected output to the arithmetic circuit 28.
The switching signal input to the selector 23 is input from the control unit 10.

In this specific example, in order to thin out the recording dots based on the nozzle positions as shown in FIG. 4 as the mask data for each block, the value of one word (16 bits) is used as the mask data in the first block. AAAAh for the mask data memory 24, 4514h for the mask data memory 25 for the second block, 1001h for the mask data memory 26 for the third block, and 0040h for the mask data memory 27 for the fourth block. are doing.

Further, the arithmetic circuit 28 is configured to perform an AND operation for each bit of the mask data and one word of the recording data from the input buffer 21. Here, the recording data is a binary image in which one bit corresponds to one pixel, and a bit value of 1 indicates recording and a bit value of 0 indicates non-recording.

Returning to FIG. 3, the configuration of the raster-column conversion unit 13 has a 16-bit × 16-bit matrix memory, and sequentially writes 16 words of recording data into this matrix. Is bit-sliced and sequentially output as one word. The writing to the matrix memory is controlled by the control unit 10 for each word, and the reading from the matrix memory is executed by the raster-column conversion unit 13 by writing 16 words, and the completion of the reading is notified to the control unit 10. It has become.

That is, in the configuration of the first embodiment, a plurality of mask data corresponding to the dot positions to be thinned out in the main scanning direction of each block in the plurality of blocks are stored in the first block mask data memory 24 to the fourth block mask data memory. 2
7 and a mask data storage unit 22 configured such that the number of dot positions to be thinned out of each mask data sequentially changes in the medium transport direction for each block.
However, using a plurality of mask data in the mask data storage unit 22, the drive control of the recording head 1 is performed so that the recording data for each block gradually increases or decreases according to the type of the medium.

<Operation> As a method of printing scan and medium conveyance, in the apparatus of this configuration, after one thinning printing scan,
The medium is conveyed by an amount corresponding to one block (4 nozzles) of the printhead, and the next thinning print scan is repeated. The print area of one block is printed four times, and the area is printed. Is completed. Further, in the four printing scans, the amount of ink applied in each printing scan is sequentially reduced.

First, recording data in raster format received from an external device is sequentially stored in the data buffer 11.

FIGS. 6 and 7 are explanatory diagrams showing the recording data array in the data buffer 11. FIG. Data buffer 11
As shown in the figure, the storage method of the recording data is as follows: the first word (D1, 1) and the second word (D1, 2) in word units (in this specific example, 16 bit units) from the data of the first line of the recording image. ) ... are stored in this order. Here, the first line is the top line of the image, the first word (D1, 1), the 151st word (D2, 1), and the 301st word (D3,
1),... Are defined in advance as the left end of the image. In the case of this specific example, one line is composed of 150 words, and one dot is one dot.
and the width of the image is 240
It is assumed that there are 0 pixels. The storage area before the storage position of the first word is prepared in advance as a storage area for NULL data (non-recorded data) for one word.

The control unit 10 stores the received print data in the data buffer 11, and starts time-division processing in parallel with storage of the received print data from the time when sufficient data for executing the print scan is stored. Then, the data necessary for the printing scan is read from the data buffer 11 and transferred to the raster-column conversion unit 13 via the data mask unit 12.

When the data of the 600th word (D4, 150) is stored, reading of the print data for the first scan of the print scan is started.

The control unit 10 outputs a switching signal of the selector 23 to the data mask unit 12 so as to use the mask data corresponding to the first block among the mask data stored in the data mask unit 12.

Thereafter, the 451st in the data buffer 11
The data of the word (D4, 1) is read and written to the data mask unit 12. The data mask unit 12 writes the written data and the first block mask data memory 2.
The arithmetic circuit 28 performs an AND process on the mask data of No. 4 and outputs the processed data to the raster-column conversion unit 13.
The raster-column conversion unit 13 stores the input data in an internal matrix memory.

The control unit 10 outputs the 301st word (D3,
1), 151st word (D2,1), 1st word (D2
The same data is read out in the order of (1, 1) and written to the data mask section 12. After that, assuming that the nozzles of the second to fourth blocks are located outside the image range, NULL data is read out and written to the data mask unit 12 12 times so that the nozzles of these blocks are not printed.

Thereafter, the above operation is repeated, and data for one scan up to the 150th word (D1, 150) is written in the data mask section 12, and the converted data is stored in the line buffer 14.

After the data for one scan is completely stored in the line buffer 14, the control unit 10 sends the medium conveyance to the LF motor control unit 18 so that the position where the image edge should be recorded coincides with the position of the nozzle # 4. An instruction is sent, and after the medium is conveyed to a predetermined position, the start of driving is notified to the SP motor control unit 17.

A recording head drive timing signal is output from the SP motor control unit 17 in synchronization with the rotation of the SP motor 4, and the line buffer 14 is synchronized with the timing signal.
Then, the recording data is read out in units of one word and transferred to the head driving circuit 15. The head drive circuit 15 outputs a drive signal to a nozzle to be printed according to the value of the print data, so that an image corresponding to the print data is formed on the medium.

In the first scanning, data obtained by processing the data of lines 4 to 1 of the recording data in the data mask unit 12 are recorded correspondingly to the nozzles # 1 to # 4 located in the first block of the head.

At the end of recording for one scan, the SP motor 4 stops and returns to the home position for the next scan. At the same time, the control unit 10 causes the LF motor control unit 18 to execute medium conveyance for one block of the nozzle of the recording head 1.

Next, a process for converting print data of the second scan is started. In the case of the second scan, the nozzles used by the print head 1 correspond to the first and second blocks # 1 to # 8, and the control unit 10 firstly uses the first block mask data memory 24 as the mask data of the data mask unit 12. Is set to use the mask data of No. 1, and the four words from the 1051th word (D8, 1) to the 601st word (D5, 1) are sequentially stored in the data mask unit 12 in the same procedure as in the first print scan. Writing is done.

Thereafter, the data of the mask data memory 25 for the second block is selected as the mask data,
4 from word (D4,1) to first word (D1,1)
Words are sequentially written to the data mask unit 12. As for the nozzles # 9 to # 16, NULL data is written as non-printing data for eight words as in the case of the first scanning.

After the processing of the raster-column conversion unit 13 is completed, the mask data is again selected for the first block mask data memory 24, and the 1052th word (D8, 2) to the 602nd word (D8, 2) of the recording data are obtained. D5, 2) are sequentially written into the data mask section 12, and the mask data is selected for the second block mask data memory 25, and the 452th word (D4, 2) to the second word (D1, 2) of the recording data is selected. 2) 4 words and 8 words of NULL data are sequentially written into the data mask unit 12. This operation is performed for one scan width of data (the 150th word (D1, 15
After execution up to 0)), the control unit 10 starts the second recording scan.

In the second print scan, the nozzles # 1 to # 4 of the print head 1 use the mask data memory 2 for the first block to store the data corresponding to the eighth to fifth lines of the print data.
The data processed by the mask data of No. 4 is recorded, and the nozzle #
5 to # 8 record data obtained by processing data corresponding to the fourth line to the first line of the recording data with the mask data in the second block mask data memory 25.

After the second print scan, the medium is transported by one block, and the data of the third scan is processed.

In the third scan, the first scan of the data mask
The data of the twelfth line to the ninth line of the recording data is processed by the mask data of the block mask data memory 24, and the data of the eighth to fifth lines of the recording data are processed by the mask data of the second block mask data memory 25. Is processed by the mask data of the mask data memory 26 for the third block to process the data of the fifth line to the first line of the print data, and the nozzles # 1 to # 12 are used to process the data of the twelfth line to the first line, respectively. Record the corresponding data.

In the fourth scan, the first scan of the data mask
The mask data of the block mask data memory 24 processes the data of the 16th to 13th lines of the recording data, and the mask data of the second block mask data memory 25 processes the data of the 12th to 9th lines of the recording data. The data of the eighth to fifth lines of the print data are written in the mask data of the third block mask data memory 26, and the fourth to first lines of the print data are written in the mask data of the fourth block mask data memory 27. Are processed, and data corresponding to the 16th line to the 1st line of the recording data is recorded in the nozzles # 1 to # 16, respectively.

In the scans after the fourth scan, the print scan is performed using all the nozzles of the head. The same processing as described above is performed while sequentially shifting the print data read position by four lines for each print scan. Will be executed.

When such processing is performed, for example, assuming that the print data is a solid fill, the position of the print dot in one print scan is the position of ● shown in FIG. Accordingly, printing is performed such that the density of dots to be printed stepwise toward the first to fourth nozzles decreases.

FIG. 1 is a conceptual diagram showing a printing result when a plurality of such printing scans are performed while the medium is conveyed. In each print scan, dot positions that have not been printed in the previously executed print scan are complemented and printed so that a print area of one block is controlled so as to be completed in four print scans. Control is performed so that the density of the recording dots sequentially decreases.

In the above specific example, an example in which the number of recording dots decreases as the medium is transported has been described. On the contrary, the recording density can be changed so as to sequentially increase, and this example will be described next. I do.

In the above description, as shown in FIG. 4, the mask data in the first block mask data memory 24 is used for the nozzles of the first block (nozzles # 1 to # 4). The mask data memory 25 for the second block is used for the nozzles of two blocks, the mask data memory 26 for the third block is used for the nozzles of the third block, and the mask data memory 27 for the fourth block is used for the nozzles of the fourth block. Although the selector 23 is controlled to use the data, the selection order is set to the fourth block nozzle in the fourth block.
The mask data memory 27 for the block is used, and thereafter, the mask data memory 26 for the third block is used for the nozzles of the second block, the mask data memory 25 for the second block is used for the nozzles of the third block, and the nozzles of the fourth block are used for the nozzles of the fourth block. Is the first
The block mask data memory 24 is changed to use each. Thus, it is easy to realize that the density of the recording dots recorded in the recording area of one block in four scans is sequentially increased for each scan.

FIG. 8 is an explanatory diagram showing an example of thinning out the recording dots based on the nozzle position when the recording density is changed so as to be sequentially increased.

In such a case, the control of the selector switching signal to the selector 23 is performed by the control unit according to the recording medium selection command transferred prior to the recording data from the host device via the I / F control unit 19. 10 is performed.

FIG. 9 is a flowchart showing the control switching operation. By specifying a medium to be recorded by an operator in a device driver program operating on a higher-level device, the device driver program outputs a recording medium selection command to the present device to select a medium specified by the operator. .

The output recording medium selection command is sent to the I / F
The control unit 10 received via the control unit 19 determines that the recording medium has been switched (step S1), and analyzes the medium type specified by the recording medium selection command (step S1).
2) It is determined whether the designated medium is plain paper having no ink holding layer or OHP paper having an ink holding layer (step S3).

In step S3, if the designated medium is plain paper, the control unit 10 controls the first block mask data memory 24 to the fourth block mask data so that the recording dot density of a plurality of scans in one block is sequentially increased. The selector 23 is switched and controlled so that the block mask data memory 27 corresponds to the nozzles of the first to fourth blocks, respectively (step S4).

On the other hand, when the designated medium is OHP in step S3, the control unit 10 controls the first block so that the recording dot density of one block in a plurality of scans is sequentially reduced.
The selector 23 is switched and controlled such that the block mask data memory 24 to the fourth block mask data memory 27 correspond to the nozzles of the fourth to first blocks, respectively (step S5).

After such switching control is completed,
By transferring the print data, a print operation is performed according to the correspondence between the set nozzle block and the mask data.

The switching of the selector 23 is controlled by a recording medium selection command transferred from a higher-level device as described above.
It is also performed by inputting the medium type from 0. That is, when the medium designation is input from the operation panel 20 (step S6), the recording medium designation value is analyzed and the corresponding switching control is performed in the same manner as the processing after step S2 described above.

The setting of the control operation of the selector 23 is set, for example, in a state corresponding to plain paper at the time of initial setting of the apparatus, and when there is no recording medium selection command or input from the operation panel 20, It operates with the initial settings.

As described above, according to the type of the medium, the dot density recorded in one of a plurality of recording scans is sequentially reduced or
Can be switched to increase or not.

Further, in this specific example, an image is formed by complementing with four printing scans. However, the number of divisions of the nozzle block of the head is changed, and the number of data mask units 12 of the number of blocks is changed. This can be easily dealt with by extending the mask data so that it can be selected and changing the medium transport amount during one scan to one corresponding to the width of one block.

For example, with the same number of nozzles 16 as in this specific example,
When the number of blocks is eight, the data mask unit 12 is changed to a configuration in which eight types of mask data can be stored and selected.
The mask data may be switched and used for each line, and the medium transport amount between the printing scans may be set to two nozzles.

Further, in this example, only one recording head 1 has been described for simplicity. However, even when a plurality of recording heads 1 are mounted on the carriage 2, the data buffer 11 and the data mask unit 12, By providing a raster-column conversion unit 13, a line buffer 14, and a head driving circuit 15 for each recording head, it is possible to cope with a plurality of colors as a color ink jet printer and easily cope with an apparatus having a plurality of heads. It is possible.

<Effects> As described above, according to the first embodiment, the density of dots recorded in one main scan is changed stepwise in the medium transport direction (sub-scan direction), and one band area of an image is changed. Is recorded in a plurality of main scans, the amount of ink applied to the recording medium can be changed in the plurality of main scans.

For example, in the case where the recording medium is formed only of a base paper having no ink holding layer and the applied ink diffuses and permeates a relatively wide area inside the medium (for example, high quality paper), Is to sequentially increase the amount of ink applied to one medium in the medium transport direction so as to sequentially increase the amount of ink applied to the medium for each recording scan. Thus, by suppressing the deflection of the medium during the next printing scan, it is possible to improve the accuracy of the printing position, prevent the medium from being stained by the rubbing of the printing head, and improve the image quality.

Conversely, in the case of a medium (for example, an OHP film) which has an ink holding layer but has a relatively small limit of the holding amount and the ink applied to the surface of the ink holding layer easily remains (for example, an OHP film), it is applied in one scan. By sequentially reducing the ink amount in the medium transport direction, the ink amount applied to the medium is sequentially reduced for each printing scan. As a result, the longer the amount of ink initially applied, the longer the time until the recording surface of the medium comes into contact with a transport mechanism such as a transport roller, and the more time it takes to absorb and fix the ink, Deterioration of image quality such as lack of surface ink due to transfer to the image transport mechanism, and contamination due to retransfer from the transport mechanism to the medium can be prevented.

<< Embodiment 2 >><Structure> FIG. 10 is a configuration diagram of a data mask section in an ink jet printer of Embodiment 2.

The data mask section of the specific example 2 includes a first mask data storage section 31, a second mask data storage section 32,
A first selector 33, a second selector 34, a third selector 35, an input buffer 21, and an arithmetic circuit 28 are provided.
Further, since the block diagram of the control mechanism in the specific example 2 is the same as that in FIG. 3 of the specific example 1, the description will be made with reference to FIG.

The first mask data storage section 31 and the second mask data storage section 32 include memories for holding data having the same number of mask positions and different mask positions (dot positions to be thinned out). That is, the first mask data storage unit 31 stores the first block mask data memory (#
1) 36th to fourth block mask data memory (# 1)
39, and the second mask data storage unit 32 includes first block mask data memories (# 2) 40 to 40 which are different from the mask data of the first mask data storage unit 31, respectively.
A fourth block mask data memory (# 2) 43 is provided.

The first selector 33 and the second selector 34 receive the outputs of the mask data memories of the first mask data storage unit 31 and the second mask data storage unit 32 in response to a selection instruction from the control unit 10, respectively. It is based on the selection. That is, the relationship between the first mask data storage unit 31 and the first selector 33 and the relationship between the second mask data storage unit 32 and the second selector 34 are the same as the relationship between the mask data storage unit 22 and the selector 23 in the first embodiment. Is the same as

The third selector 35 is a selector that selects the output of the first selector 33 and the second selector 34 and outputs the selected output to the arithmetic circuit 28. The selection is instructed by the control unit 10. It is configured as follows. The input buffer 21 and the arithmetic circuit 28 have the same configuration as in the first embodiment.

As described above, the data mask unit of the second embodiment is different from the data mask unit 12 of the first embodiment in that the mask data memory is divided into a plurality of tables for each block (the first block mask data memory (# 1)). 36 to the fourth block mask data memory (# 1) 39, and the first block mask data memory (# 2) 40 to the fourth block mask data memory (# 2) 43. # 3 for selecting whether to use # 1 / # 2)
Is provided.

<Operation> In the specific example 2, the basic operation is similar to that of the specific example 1, and the control unit 10 writes the recording data from the data buffer 11 to the data mask unit 12 and selects the written data. The processing flow is to perform arithmetic processing on the mask data and transfer the processing result to the raster-column conversion unit 13.

The difference from the first embodiment is that, in the first embodiment, prior to transfer of one block (four lines), the control unit 10 selects mask data corresponding to the block and transfers the selected mask data. In this example, two mask data are prepared for one block, and the mask data is alternately provided for each line. I use it by switching.

FIG. 11 is an explanatory diagram showing an example of thinning out the recording dots by the nozzle position in the specific example 2. In the illustrated case, the first mask data is used as the mask data of the data mask unit 12.
AAAh is set as the first block mask data memory (# 1) 36 of the mask data storage unit 31, and 5555h is set as the first block mask data memory (# 2) 40 of the second mask data storage unit 32. Hereinafter, the second block mask data memory (# 1) 37 is 28C2h, and the second block mask data memory (# 1) is
2) 41 is 1451h, the third block mask data memory (# 1) 38 is 8008h, the third block mask data memory (# 2) 42 is 4004h, and the fourth block mask data memory (# 1) 39 is 0100h. , Fourth
The block mask data memory (# 2) 43 is 0080
The value is set as h.

Next, the flow of the mask data processing is shown in FIG.
This will be described using the memory array of the data buffer 11 in FIG. In the first scan, the control unit 10 controls the data (the 451st word (D4, 1) to the 1st word (D1, 1)) corresponding to the nozzles # 1 to # 4 of the first block, as in the first example.
1)) is written in the data mask section 12, and the second to fourth blocks write NULL data for 12 words outside the print area.

In the case of writing the first block, the control unit 1
0 outputs a selection signal for selecting data of the first mask data storage unit 31 of the first block to the data mask unit 12 first. Then, the 451st word (D4, 1)
Is written to the data mask unit 12.

Next, the mask data of the first block mask data memory (# 2) 40 of the first block is selected as the mask data, and the data of the 301st word (D3, 1) is written into the data mask section 12. Similarly, the first again
Mask data memory for the first block of the block (# 1)
36, data of the 151st word (D2, 1) is written, and the mask data memory for the first block (# 2) 40 is selected, and the first word (D1, 1) is selected.
Write the data of

By repeating such a data processing operation for one band, the data of the fourth line printed by nozzle # 1 and the data of the second line printed by nozzle # 3 are all for the first block. Mask data memory (# 1)
Mask processing is performed using the 36 mask data,
The data of the third and first lines recorded by the nozzles # 2 and # 4 are respectively stored in the first block mask data memory (#
2) Mask processing is performed using 40.

By performing the above-described operation for each nozzle block in the same manner, it is possible to perform a masking process as indicated by a circle in FIG. In addition, by using the mask patterns # 1 and # 2 interchanged for each ink color and using them, 2
Colors can be recorded at complementary positions.

Further, in the above description of the specific example 2, the example in which the recording dots are reduced as the medium is transported is described. However, when the recording density is sequentially increased, the same as in the specific example 1 is performed. it can. That is, the first selector 33 and the second selector 34 of the first block mask data memory (# 1) 36 to the fourth block mask data memory (# 1)
4) 39 and mask data memory for first block (# 2)
40th to fourth block mask data memory (# 2) 43
, The recording density can be gradually increased.

<Effects> As described above, according to the specific example 2, in addition to the configuration of the specific example 1, the position of the recording dot in the main scanning direction is different from the adjacent line in the medium transport direction. As is clear from FIG. 11, the recording dots in one operation are not adjacent to each other in the main scanning and sub-scanning directions, and the degree of overlapping of the recording dots in one scanning with the adjacent dots can be reduced. . Accordingly, in a medium which is easily blurred, in addition to the effect of the specific example 1 in which the dot shape can be prevented from being distorted due to the interference between the dots and the color blur, the image quality of the formed image can be further improved. .

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a recording method of an ink jet printer according to a first embodiment of the present invention.

FIG. 2 is an external view of an apparatus mechanism of the inkjet printer.

FIG. 3 is a block diagram of a control mechanism in the inkjet printer.

FIG. 4 is an explanatory diagram showing an example of thinning out recording dots based on nozzle positions in a specific example 1.

FIG. 5 is a configuration diagram of a data mask unit of a specific example 1.

FIG. 6 is an explanatory diagram (part 1) illustrating a print data array in a data buffer.

FIG. 7 is an explanatory diagram (part 2) illustrating a recording data array in a data buffer.

FIG. 8 is an explanatory diagram showing an example of thinning out recording dots based on nozzle positions when the recording density is changed to be sequentially increased in the first specific example.

FIG. 9 is a flowchart illustrating a control switching operation according to the first embodiment.

FIG. 10 is a configuration diagram of a data mask unit in the ink jet printer according to the second embodiment.

FIG. 11 is an explanatory diagram showing an example of thinning out recording dots based on nozzle positions in specific example 2.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 recording head 7 recording medium 10 control unit 12 data mask unit 22 mask data storage unit 23 selector 24, 36, 40 first block mask data memory 25, 37, 41 second block mask data memory 26, 38, 42 Third block mask data memory 27, 39, 43 Fourth block mask data memory 31 First mask data storage unit 32 Second mask data storage unit 33 First selector 34 Second selector 35 Third selector

Claims (5)

[Claims] 1. A head having a plurality of ink ejection elements arranged in a medium transport direction, wherein dots to be recorded in one main scan are thinned out, and all dots are recorded by recording in a plurality of main scan directions in the same scanning portion. A recording method for an ink jet printer, comprising: changing the density of recording dots in one scan stepwise with respect to the medium transport direction. 2. The recording method for an ink jet printer according to claim 1, wherein the transport of the medium is performed by an amount shorter than an arrangement length of a plurality of ink ejection elements. 3. A head having a plurality of ink ejection elements arranged in a medium conveyance direction, wherein an arrangement length of the plurality of ink ejection elements is divided into a plurality of blocks, and medium conveyance is performed for each block. In addition, in an ink jet printer that thins out dots to be printed in one main scan and prints all dots by printing in a plurality of main scanning directions on the same scanning portion, the dots to be thinned out in the main scanning direction of each block in the plurality of blocks A mask data storage unit having a plurality of mask data corresponding to the positions, and configured such that the number of dot positions to be thinned out for each mask data is sequentially different in the medium transport direction for each block; and And a control unit for controlling the driving of the head so that the recording data for each block gradually increases or decreases according to the type of the medium. Jet printer, characterized in that there was e. 4. The recording method for an ink jet printer according to claim 1, wherein positions of the recording dots in the main scanning direction are different from adjacent lines in the medium transport direction. 5. A head comprising a plurality of ink ejection elements arranged in a medium conveyance direction, wherein an arrangement length of the plurality of ink ejection elements is divided into a plurality of blocks, and the medium is conveyed for each block. In addition, in an ink jet printer that thins out dots to be printed in one main scan and prints all dots by printing in a plurality of main scanning directions on the same scanning portion, the dots to be thinned out in the main scanning direction of each block in the plurality of blocks A first mask data storage unit having a plurality of mask data corresponding to the positions, and configured such that the number of dot positions to be thinned out for each mask data is sequentially different along the medium transport direction for each block; A second mask data storage unit having the same number of dot positions to be thinned out as the first mask data storage unit and having different dot positions to be thinned out; The number of mask data is used to control the drive of the head so that the recording data for each block gradually increases or decreases in accordance with the type of the medium, and the first mask data storage unit and the second mask data storage are performed. An ink jet printer, comprising: a control unit for controlling the driving of the head by alternately using the mask data of the units for each line along the medium transport direction.