JP2002001926A - Ink jet printing apparatus and image forming method - Google Patents

Abstract

(57) [Summary] In an ink jet printing apparatus that performs so-called multi-pass printing, a head driving method such as block dispersion division driving in which only a position decimated for each scan (pass) is driven is limited. Therefore, it is possible to simplify or speed up the process of generating the mask table and to reduce the memory capacity. SOLUTION: A substantial mask by driving only a limited coordinate position typified by block dispersion division driving or the like by a single print scan and a mask by replacing print dots included in image data with non-print dots. The dot formation required for each print scan is performed by the logical product of This makes it possible to use a single mask table by a single generation process, regardless of the selection state of the nozzles to be used from a plurality of nozzles mounted in the sub-scanning direction to correspond to the sub-scanning direction registration process, Simplification and speeding up of the mask table generation processing can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printing apparatus and an image forming method for forming an image by discharging ink on a print medium. More specifically, the present invention relates to a method for scanning the same print area a plurality of times. This relates to data generation control in each scan when forming an image.

[0002]

2. Description of the Related Art In recent years, OA equipment such as a personal computer, a copying apparatus, and a word processor has become widespread. As one type of apparatus for performing image formation (printing) in these equipment, a digital image is printed by an ink jet system. Devices are rapidly developing and becoming popular. In particular, the colorization of OA equipment has been advanced along with the sophistication thereof, and accordingly, various color ink jet printing apparatuses have been developed.

In general, an ink jet printing apparatus includes a carriage on which a printing means (print head) and an ink tank are mounted, a conveying means for conveying a print medium, and a control means for controlling these. Such an apparatus serially scans a print head that ejects ink from a plurality of ejection ports as, for example, droplets in a direction (main scanning direction) orthogonal to a transport direction (sub-scanning direction) of a print medium, and performs printing between each main scan. The printing medium is intermittently transported by an amount equal to the width. Further, in the case of a color-compatible inkjet printing apparatus, a color image is formed by superimposing ink dots ejected by a print head corresponding to a plurality of colors.

As a method of discharging ink in an ink jet printing apparatus, a heating element (electric heat energy converter) is provided in the vicinity of a discharge port, and an ink is locally heated by applying an electric signal to the heating element. Using a thermal method in which a pressure change is caused and ink is ejected from an ejection port, or an electric pressure conversion means such as a piezo element,
A piezo method that applies mechanical pressure to ink to eject ink has been used. Generally, in the former thermal method, a print head can be manufactured by applying the same technology as the semiconductor manufacturing process, so that high-density mounting of fine nozzles corresponding to output of high-definition images is easy. It has the feature of. On the other hand, the latter piezo method has excellent discharge controllability and has a high degree of freedom in ink selection and a relatively long head life because it does not need to consider the action of heat.

In any case, the ink jet printing method prints characters and figures by discharging a very small amount of ink from a discharge port onto a print medium in accordance with a print signal, and is non-impact. It has advantages such as low noise, low running cost, easy downsizing of the device, and relatively easy colorization, so it is used together with a computer or word processor, or used alone. In a printing apparatus such as a copying machine, a printer, a facsimile, etc., which is used in the above-mentioned, it is widely used as an image forming means.

In the ink jet printing method,
In order to obtain color images with high color development without ink bleeding,
In some cases, special coated paper with an ink-absorbing layer is used, but recently, with the improvement of ink, etc., those that have the printability of so-called plain paper widely used in printers and copiers have also been put into practical use. Have been. Furthermore, it is desired to support various print media such as OHP sheets, cloths, plastic sheets, etc.
Development and commercialization of a printing apparatus that enables optimum printing regardless of the type of print medium even when a print medium having different ink absorption characteristics are selected as needed are being promoted. Also, regarding the size of the print medium, large-sized posters for advertisements and woven fabrics such as clothing have been required.

As described above, the demand for an ink-jet printing apparatus has been increasing not only in personal use and office use but also in a wide range of industrial fields as an excellent printing means, and it has been demanded to provide even higher-quality images. It can be said that the demand for the development is increasing.

In general, a color ink jet printing method uses three color inks of cyan (Cy), magenta (Mg) and yellow (Ye), and further uses four color inks added with black (Bk). To achieve color printing. In an ink jet printing apparatus that prints such color images, unlike a monochrome ink jet printing apparatus that prints only characters such as characters, numbers, and symbols, various elements such as color development, gradation, and uniformity are not used. Printing performance is required.

However, the quality of an image to be printed largely depends on the performance of the print head alone. That is, the shape of the ejection port of the print head, the electrothermal transducer (ejection heater) or the electric pressure transducer (piezo element) for generating energy used for ejecting ink.
Each nozzle (hereinafter referred to as an ejection port, a liquid path communicating with the ejection port, and an element that generates energy used for ink ejection) generated in the print head manufacturing process, such as variation in elements, etc. Such a difference affects the ejection amount and ejection direction of each of the ejected inks, resulting in unevenness in density of a finally formed print image, which causes deterioration in image quality. As a result, there is a “white” portion that cannot periodically satisfy the area factor of 100% in the head main scanning direction,
Conversely, dots overlap more than necessary or white streaks occur. These phenomena are usually perceived by the human eye as uneven density.

Therefore, a method called a multi-pass printing method has been proposed as a measure against such density unevenness. For simplicity, this method will be described by taking as an example a case where a print head having eight nozzles for discharging monochromatic ink is used. Further, here, a table mask method of generating pass data by thinning out print data using a random mask pattern in which print dots and non-print dots are arranged in a random manner, and implementing two-pass printing Will be described.

FIG. 1 is a diagram showing an example of a mask table for each print scan. Table head areas A and B are complementary mask tables used in the first and second passes, respectively. The table is one bit per dot,
“0” indicates a masking target, and “1” indicates a non-masking target. Each of the mask tables A and B is a table having a size corresponding to 12 pixels in the main scanning direction and 4 pixels in the sub-scanning direction. The tables are repeatedly developed in the main and sub-scanning directions and used as mask data. Here, the number of nozzles provided in the print head is eight, and the number of pixels corresponding to the paper transport amount in two-pass printing is 8/2 = 4, which is equal to the size of the tables A and B in the sub-scanning direction.

FIG. 2 is a diagram for explaining an aspect of print scanning using the mask table shown in FIG. For eight lines of data corresponding to eight nozzles, A and B are applied as mask patterns every four lines. In each print scan, mask processing of image data is performed using the stored mask table (processing for replacing dots to be printed with non-print dots in accordance with image data).
To generate and output data for each pass. Specifically, by calculating the logical product of the image data and the mask data, if the mask data is “1”, the image data is output as it is, and if the mask data is “0”, the image data is output. This is realized by always replacing data with “0”. All image areas are always masked in the order of A and B by two scans to generate print data.

In this way, by printing one line using two different nozzles, a high-quality image with reduced density unevenness can be formed. Also,
The multi-pass printing method suppresses bleeding by drying while drying the ink, and suppresses the temperature rise of the print head that causes ejection failure by reducing the number of print dots for each scan. Effects can be achieved at the same time. Here, the description has been made in the main scanning direction. However, printing is performed by thinning out continuous dots in the sub-scanning direction, so that higher image quality can be achieved.

As described above, the pass data for each scan is generated by thinning out the print data using a random mask pattern in which print dots and non-print dots are randomly arranged. In addition to the method of generating (called the table mask method),
A method of generating pass data by thinning out print data using a zigzag / inverted zigzag pattern (referred to as a fixed mask method) or a thinning process by focusing on print dots themselves corresponding to image data A method of generating data for each data (referred to as a data mask method) is known.

By the way, in a thermal type ink jet printing apparatus, a block division driving method is adopted mainly for the purpose of suppressing power consumption. In this method, a nozzle array arranged in a print medium transport direction (sub-scanning direction) is divided into a plurality of blocks, and each block is driven in a time-division manner, that is, with a time lag, and is briefly described below. I do.

FIG. 3 is a schematic diagram showing an example of a nozzle array in a print head, FIG. 4 is a diagram for explaining a standard block division driving mode for a print head having such a nozzle array, and FIG. It is a figure showing an example of allocation of a nozzle included.

FIG. 3 is a view of the print head as viewed from the side of the discharge port that discharges ink, for example, as droplets. In this example, 256 nozzles are provided in two rows, and these rows are formed. Even numbered nozzles (# 0, # 2,.
., # 254) and odd-numbered nozzles (# 1, # 3,.
# 255) are arranged with their positions shifted in the vertical direction (sub-scanning direction) in the figure. The interval between columns is equivalent to 8 pixels in the horizontal direction (main scanning direction) in the figure. These 256
The nozzles are divided into 16 blocks, and each block is assigned a nozzle as shown in FIG.
Then, using the print timing of the pixels arranged in the main scanning direction as a trigger, as shown in FIG.
6) Each nozzle is sequentially driven. Actually, each nozzle is, for example, 1.2 μm in the main scanning direction according to the block number.
m.

Here, as one method for improving the throughput of image formation, it is conceivable to increase the moving speed of the carriage for main scanning of the print head to shorten one scanning time. However, as the carriage moving speed increases, the time interval corresponding to the distance between adjacent blocks decreases, and it becomes difficult to secure a sufficient drive time (drive time of the discharge heater) for each block. Also,
In general, the upper limit of the stable driving frequency is about several tens of kHz, and if the moving speed of the carriage is increased, all the continuous pixels may not be formed stably.

As an effective method for avoiding these problems, a block distributed division driving method has been proposed.

FIG. 6 is an explanatory diagram of such block distributed division driving. In this driving method, eight even-numbered blocks and eight odd-numbered blocks are alternately driven in columns (columns) out of a total of 16 blocks. When focusing on a single nozzle, driving is performed every other pixel. become. Also, as compared with the standard block division driving (FIG. 4), it can be seen that the drivable time for each block is doubled.

FIG. 7 shows dot positions (coordinates) that can be driven in a single scan. Accordingly, even when the carriage is driven at a high speed, the driving intervals of the nozzles are expanded, the driving frequency of the head is maintained, and the required driving frequency of each block is maintained without causing the ink landing position deviation due to the deviation of the driving timing. Driving time can be secured.

[0022]

However, on the other hand, the following problems arise with the adoption of such block distributed division driving.

When a relative displacement between the print heads of each ink color occurs due to a mounting error of the print head or the like, this appears as a color shift, which greatly degrades the image quality. For this reason, in a serial scan type printer such as an ink jet printing apparatus, it is generally strongly desirable to perform dot formation position registration processing in the main scanning direction and the sub scanning direction. The registration processing in the main scanning direction is realized by adjusting the ejection timing in pixel units or minute time units smaller than the pixel formation time interval.

On the other hand, registration processing in the sub-scanning direction is realized by preparing several upper and lower nozzles among the mounted nozzles in advance for the registration processing, and selecting the nozzles actually used for printing among the mounted nozzles. Is done. Here, when the nozzles used for printing are sequentially shifted by making the registration in the sub-scanning direction function sequentially with respect to the block dispersion division drive, the dot position that can be driven in a single scan changes as shown in FIG. I do. In other words, this means that even if the same head drive is performed, the dot position that can be printed on the paper surface changes according to the registration processing state in the sub-scanning direction.

Thus, in the pass data generation processing by the table mask method described above, it is necessary to generate a mask table according to the registration value in the sub-scanning direction. Since the registration value of the print head for each ink color is independent, up to four types of mask tables are generated for four color inks. In addition, the table memory, which should have been required only one time, is expanded four times.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a mask table for a head driving method such as a block dispersion division driving for driving only a position thinned out for each scan. It is an object of the present invention to make it possible to simplify or speed up the generation processing of the data and reduce the memory capacity.

[0027]

In order to solve the above-mentioned problems, the present invention uses an ejection section in which a plurality of ejection ports for ejecting ink are arranged, and the ejection section is connected to the plurality of ejection ports. While scanning a plurality of times in a direction different from the arrangement direction, between each scan by transporting the print medium in an amount less than the arrangement width of the plurality of ejection ports in a direction orthogonal to the scanning direction, An ink jet printing apparatus for forming an image using different discharge ports for the same area on the print medium, wherein the image data is formed by performing image forming by the plurality of scans. A data output means for outputting data subjected to a masking process for setting a part in a non-printing state; Means for forming an image by driving the discharge unit based on a logical product of the pattern and the pattern determined according to the drive mode in order to perform a limited ink discharge in the mouth. I do.

Further, the present invention uses an ejection section in which a plurality of ejection ports for ejecting ink are arranged, and scans the ejection section a plurality of times in a direction different from the arrangement direction of the plurality of ejection ports. In addition, during each scan, the print medium is relatively conveyed by an amount smaller than the arrangement width of the plurality of ejection ports in a direction orthogonal to the scanning direction, so that different ejections are performed on the same area on the print medium. An image forming method for forming an image using an exit, wherein the image data is subjected to a masking process for setting a part of the image data relating to printing to a non-printing state in order to perform the image forming by the plurality of scans. A data output step of outputting the selected data, the masked data, and a driving mode for causing the plurality of ejection ports to perform limited ink ejection according to a position in a print area. Based on the logical product of the determined pattern Flip, characterized in that comprises and a step of forming an image by driving the discharge portion.

With these, the print head (ejection unit)
By the logical product of the substantial mask processing according to the driving mode and the mask processing for the image data, it is possible to form print dots in each print scan.

In the above-mentioned ink jet printing apparatus, the data output means includes means for storing a table of mask data used for performing the mask processing, and mask processing for performing mask processing on the image data with reference to the table. Means.

In the image forming method, in the data output step, mask processing may be performed on the image data with reference to a table of mask data used to generate the image data. it can.

According to these configurations, the present invention can be applied to a case where a table mask system for performing mask processing of image data by referring to a mask table is adopted.

Further, in the above, the discharge section is divided into a plurality of blocks each composed of a plurality of discharge port groups, and as the driving mode, in a single scan, of the plurality of blocks, May be selectively driven. That is, the present invention can be applied to a case where block distributed division driving for driving only a plurality of predetermined blocks is employed.

A mode for selectively driving a part of the plurality of blocks in the single scan;
And a mode for driving everything.

Further, in the above, the discharge section may include an element for generating thermal energy for causing film boiling of the ink as energy used for discharging the ink from the discharge port. That is,
The present invention can be applied to an ink jet printing apparatus provided with an electrothermal converter.

Alternatively, the ejection section may include an element that applies energy to the ink as energy used for ejecting the ink from the ejection port. That is, the present invention can be applied to an ink jet printing apparatus having an electric pressure conversion unit.

In this specification, "print"
(Sometimes referred to as "records") refers not only to the formation of significant information such as characters and figures,
It also refers to the case where images, patterns, patterns, etc. are widely formed on a print medium, or whether the medium is processed, irrespective of whether or not it has been exposed so that humans can perceive it visually. I do.

Here, the "print medium" is not limited to paper used in a general printing apparatus, but also broadly refers to a material that can accept ink, such as a cloth, a plastic film, and a metal plate.

Further, “ink” is to be interpreted broadly as in the definition of “print” described above, and is formed on a print medium to form an image, a pattern, or a pattern, or to process the print medium. Liquid that can be provided to

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

1) First Embodiment 1.1) Configuration of Printing Apparatus FIG. 9 schematically shows a configuration example of a printing section of an ink jet printing apparatus to which the present invention can be applied.

In FIG. 9, reference numeral 301 denotes a print head in which ink tanks in which color inks of four colors (Bk, Cy, Mg, Ye) are respectively enclosed, and a plurality of nozzles corresponding to each of the ink tanks are arranged. It is composed of four independent discharge units in the form of a so-called multi-nozzle head. It is assumed that the ejection unit constituting the print head 301 has 256 nozzles arranged in the print medium transport direction for four colors of Bk, Cy, Mg, and Ye.

302 supports the print head 301,
This is a carriage for moving this during a printing operation. The carriage 302 is at the home position HP shown in FIG. Reference numeral 303 denotes a transport roller, which rotates in the direction of the arrow in the figure while holding down the print medium 306 together with the auxiliary roller 304, and feeds the print medium 306 in the Y direction as needed. Reference numeral 305 denotes a feed roller that feeds the print medium 306 and plays a role in suppressing the print medium 306 similarly to the transport roller 303 and the auxiliary roller 304.

The basic printing operation in the above configuration will be described.

During standby, the carriage 302 at the home position HP moves in the X direction (main scanning direction) according to a print start command, and in the process, a plurality of nozzles of a discharge unit are driven in accordance with print data, thereby printing a print medium. Ink is ejected onto the 306 to perform a printing operation. When printing to the end in the X direction of the print medium 306 is completed, the carriage 302 returns to the home position HP. At this time, by rotating the transport roller 304 in the direction of the arrow, the print medium 306 is transported by a predetermined width in the Y direction (sub-scanning direction), and printing in the X direction is started again. By repeating such a scanning operation and a transporting operation, printing of image data is realized.

FIG. 10 is a block diagram showing a schematic configuration example of the overall control circuit of the ink jet printing apparatus shown in FIG.

The printing apparatus of this embodiment is connected via an interface 605 to a host apparatus 624 serving as a supply source of image data relating to printing. As the host device 624, a computer, an image scanner, a digital camera, or any other appropriate form can be used.

For example, a CPU 601 which can take the form of a microprocessor serves as a main control unit of the printing apparatus, and includes a ROM 602 storing a control program and an EEPROM 603 storing an updatable control program, a processing program, various constant data, and the like. And a RAM 604 for storing command signals and print information received from the host device 624 via the interface 605.
To control the printing operation based on the information stored in these memories. Further, the CPU 601
Output port 608 and carriage motor control circuit 61
By moving the carriage motor 611 through the output port 60,
The transport mechanism 612 including the transport roller 304 is operated by operating the transport motor 614 via the transport motor 8 and the transport motor control circuit 613. Further, the CPU 601
By driving the print head 301 via the print head control circuit 621 based on the print information stored in the RAM 604, a desired image can be printed on a print medium.

The power supply circuit 619 outputs a logic drive voltage signal Vcc (for example, 5 V) for operating the CPU 601 and the print head control circuit 621, various motor drive voltage signals Vm (for example, 24 V), and the print head 301.
A voltage signal Vh (for example, 12 V) for driving the ejection energy generating element (e.g., ejection heater) is output. Further, instruction information from the user input from operation keys 607 on the operation panel is transmitted to CPU 601 via input port 606. In addition, a command from the CPU 601 is transmitted to the LED control circuit 61 via the output port 609.
LED is lit in response to this,
When transmitted to the display control circuit 617, a message is displayed on the LCD 618. A CPU bus 623 connects the various components described above to one another.

The ink jet printing apparatus according to the present embodiment employs a multi-pass printing method in which the same print area is scanned a plurality of times to form an image. As described above, in multi-pass printing, a single line is formed using a plurality of nozzles, thereby suppressing density unevenness due to a slight difference in ink ejection amount and ejection direction for each nozzle, and simultaneously performing This is a printing method in which the print duty for each is reduced to prevent image quality deterioration due to ink bleeding or the like. In the present embodiment, a table mask method of generating pass data by masking image data using a mask table is adopted.

In the present embodiment, as described with reference to FIGS.
Each color discharge unit has 256 nozzles, which are divided into 16 blocks, and the even-numbered nozzles and the odd-numbered nozzles are arranged apart from each other by 8 pixels in the main scanning direction. Shall be. And mount 2
Of the 56 nozzles, only the adjacent 240 nozzles are involved in image formation, and the remaining 16 nozzles are used for registration processing in the sub-scanning direction. In other words, it is possible to shift up to eight nozzles vertically (in the sub-scanning direction) up to a maximum of eight nozzles and perform adjustment in 17 steps. The print resolution is 1200 dpi (dots / inch; reference value; the same applies hereinafter) in the main scanning direction, and 1200 dpi in the sub-scanning direction, which is equal to the nozzle array density of the ejection section.

The present embodiment also has a plurality of head drive modes corresponding to a plurality of carriage drive speeds. The carriage speed is selectively used in two stages: low-speed driving of 423 mm / s corresponding to 20 kHz driving for 1200 dpi, and high-speed driving of 846 mm / s corresponding to 40 kHz driving for 1200 dpi. The driving frequency of the print head is 20 kHz,
In the carriage low-speed drive, the standard block division drive (head standard drive mode) that always drives all blocks is used.
In the carriage high-speed drive, block distributed division drive (head distributed drive mode) for alternately driving even blocks and odd blocks is used. The modes of the block standard division drive and the block distribution division drive are the same as those described with reference to FIGS. 4 and 6, respectively.

Further, by combining the number of print passes and the head drive mode corresponding to the carriage speed in the above-described multi-pass printing, three types of print modes, "high-speed mode", "standard mode", and "high image quality mode" are provided. Have. The "high-speed mode" implements 4-pass printing in the head distributed driving mode, the "standard mode" implements 8-pass printing in the head distributed driving mode, and the "high image quality mode" implements 8-pass printing in the head standard driving mode. These are all unidirectional prints, and an image is formed only in the forward main scan.

The mode is selected by the host device 624.
Can be performed in response to a user's instruction via the operation panel or in response to a user's instruction input from operation keys 607 on the operation panel.

1.2) Generation of Print Data Hereinafter, an operation of generating print data in each print scan of the present embodiment will be described. Here, for simplicity, processing for a single ink color will be described.

FIG. 11A shows print data (pass data) for each print scan for realizing multi-pass printing.
FIG. 2 is a functional block diagram schematically illustrating a path data generation processing system for generating a path data. The illustrated processing system includes the hardware of the printing apparatus control system and the CPU 601 shown in FIG.
Can be realized as a part of a function (software) executed by the software.

Reference numeral 201 denotes a memory unit for temporarily storing image data that has been subjected to image processing for printing and that has been input from outside the path data generation processing system. The memory unit 201 may use a predetermined memory area of the RAM 604 in FIG. Reference numeral 202 denotes an input control unit;
The print data is written into the printer. An output control unit 203 performs read processing of print data based on the position of the print head 301 with respect to the print medium.

A table storage unit 204 stores a mask table. A mask processing unit 205 performs mask processing of image data as described later using a mask table in the table storage unit 204 to generate path data. The generated path data is supplied to the print head 301 via a head control block 622 which is a component of the print head control circuit 621.

An original table storage unit 206 in the control unit 208 stores table data (described later) on which a mask table is generated. 207 is the control unit 2
A table generation unit 08 generates a mask table based on the original mask table stored in the original table storage unit 206 and outputs the generated mask table to the table storage unit 204. The control unit 208 monitors the state of each unit described above and performs various controls related to path data generation in response to control signals from inside and outside the path data generation processing system. That is, for example, a mode switching signal (S0, S1) for generating a mask table or setting a drive mask (described later) according to a drive mode (head standard drive, block dispersion division drive, etc.) according to mode information. Control the output.

The head control block 622 drives the print head 301 in the drive mode selected according to the mode switching signal (S0, S1) for the pass data subjected to the mask processing by the mask processing unit 205.

FIG. 11B shows the correspondence between the contents of the mode switching signal and the drive mode or drive mode of the print head. Here, the combination of (S0, S1) = (1, 1) corresponds to the head standard drive mode. In this case, no drive mask is applied, and the pass data is supplied to the print head 301 as it is. In the “high image quality mode”, this combination is always used. (S0, S1) = (1,0)
The combination of and (S0, S1) = (0,1) corresponds to the block distribution division drive mode, and in the former, the odd-numbered block and the even-numbered block are arranged in order, whereas in the latter, the even-numbered block and the odd-numbered block are arranged. A substantial mask is applied to the path data so that the driving is performed in the order of the blocks. In the "standard mode", the combination is appropriately switched for each scan. Hereinafter, a basic path data generation operation of the entire path data generation processing system will be described.

When the raster-scanned binary image data is input from outside the pass data generation processing system, the image data is temporarily stored in the memory unit 201 via the input control unit 202. The output control unit 203 controls the memory unit 2 for each scan in accordance with the position of the nozzle group corresponding to each ink color on the print medium based on the print area control from the control unit 208.
The binary image data stored in 01 is sequentially read and output. Here, one data transfer unit is 240 pixel data corresponding to the number of used nozzles. Mask processing unit 20
In step 5, mask processing (replacement of print dots with non-print dots) of image data is performed using the mask table stored in the table storage unit 204 to generate and output pass data. Specifically, the logical product of the image data and the mask data is calculated, and the mask data is “1”.
, The image data is output as it is, and if the mask data is “0”, the image data is always replaced with “0”.

First, a description will be given of a table generation and a mask process using the table in the "high image quality mode" in which 8-pass printing is performed by standard head driving.

FIG. 12 is a diagram showing an example of a mask table for each print scan, in which A, B, C, D, E, F, G,
H is a complementary mask table used in the first pass, the second pass, the third pass, the fourth pass, the fifth pass, the sixth pass, the seventh pass, and the eighth pass, respectively. The table is 1
Bit / dot, “0” indicates a masking target, and “1” indicates a non-masking target. The mask tables A to H each have 1024 pixels in the main scanning direction,
This is a table having a size corresponding to 30 pixels in the sub-scanning direction, which is repeatedly developed in each direction and used as mask data. Since the number of nozzles used for printing is 240, the number of pixels corresponding to the paper transport amount in 8-pass printing is 240/8 = 30, which is equal to the size of the mask table in the sub-scanning direction.

The basic method of generating such a mask table will be described. The table generation unit 207 uses the original mask tables stored in the original table storage unit 206 to generate each of the mask tables A, B, C, D, and D.
E, F, G, and H are generated and output to the table storage unit 204. The original mask table is basically each 8-bit data composed of a random number sequence, and has a size corresponding to 1024 pixels in the main scanning direction and 32 pixels in the sub-scanning direction. 8
In pass printing, the remainder of each 8-bit data divided by “8” is “0”, “1”, “2”, “3”, “4”,
"5", "6", and "7" are generated. And the remainder "0", "1", "2", "3", "4", "5",
Eight tables A, B, and B that appropriately generate “1” that defines a non-mask target corresponding to each of “6” and “7”
C, D, E, F, G, and H are created and stored in the table storage unit 2
04. The duty (generation duty of non-mask data) of each table is substantially uniform, and is 12.5%
It is about. Each table size in the sub-scanning direction is 30 pixels.

FIG. 13 is a view for explaining a form of print scanning using the mask table shown in FIG.
For 240 lines of data corresponding to 240 used nozzles, mask tables A, B, C,
D, E, F, G, and H are sequentially applied as mask patterns. All image areas are always A, B, C, D, E, F,
Print data is generated by performing mask processing in the order of G and H.

The pass data for each print scan generated in this manner is output to a head drive block (print head control circuit 621), and a drive signal is applied to the print head 301 to form dots. In the “high image quality mode”, since the head standard drive is used, the above-described control unit 208 sends (S
(0, S1) = (1, 1) is always supplied so that all print dots based on the generated path data can be formed on the print medium surface in a single print scan. .

Next, the table generation and the mask processing using the tables in the "standard mode" and the "high-speed mode" characteristic of the present embodiment will be described. Here, the "high-speed mode" in which 4-pass printing is performed by block dispersion division driving will be mainly described in detail.

In the "standard mode" and the "high-speed mode", since the block dispersion division driving is performed, dots based on all the pass data are not formed in a single scan, and complementary dot formation is performed in a plurality of scans. Done. This is realized by thinning out the drive timing, which is substantially equivalent to masking the data, and is called a mask by the head drive (drive mask). FIG. 11 (A)
The control unit 208 generates a mask table for generating pass data in consideration of an image to be finally printed by the logical product of the pass data and the drive mask.
This makes it possible to cope with the same table generation processing regardless of the selection state of the used nozzle area in the mounted nozzle group depending on the registration in the sub-scanning direction. In other words, a common mask table can be used even when each ejection unit takes a different adjustment value of registration in the sub-scanning direction.

The driving mask by the block distributed division driving will be described with reference to FIG. 14 and FIG. The head is driven by scanning s (FIG. 14 (A)) in which even blocks and odd blocks are alternately driven in each column (column), and conversely, odd blocks and even blocks are alternately driven in each column (column). The driving scan t (FIG. 14B) is performed alternately. The control unit 208 described above controls the head control block 6
For S22, the combination of (S0, S1) = (1, 0) and the combination of (S0, S1) = (0, 1) are appropriately switched for each scan, thereby applying print data (dots) in scan s. The mask to be formed is a driving mask S
(FIG. 15A), the mask applied to the print data (dots) in the scan t is the drive mask T (FIG. 15A).
(B)).

FIG. 16 shows how the drive mask is used for each print scan. As shown in this figure, an area used in the order of the drive masks S, T, S, T and an area used in the order of the drive masks T, S, T, S alternately for four print scans. Exists. In any case, the used nozzle area can be driven 100% by the first pass and the second pass, and by the third pass and the fourth pass. The drive mask shown in FIGS. 15A and 15B is an example in the case where the registration value in the sub-scanning direction is for eight nozzles, and this corresponds to 256 mounted nozzles.
In this state, there are unused nozzles at the top and bottom of each of eight nozzles. As described above, when the used nozzle area in the mounting nozzle is changed by changing the registration value in the sub-scanning direction, the drive mask for each scan s and t changes as described with reference to FIG. . However, even if the area around the used nozzle changes due to the registration process, similarly, 100% of the area can be driven by the first pass and the second pass, and also by the third pass and the fourth pass. Absent.

Next, the most characteristic feature of this embodiment is
A virtual mask table that completes head drive data generation based on logical product with a drive mask will be described.

In the "high-speed mode", since 4-pass printing is performed, the mask table is composed of A, B, C, and D, which are used in the first, second, third, and fourth passes, respectively. . The table size in the sub-scanning direction is twice that of the high image quality mode (8-pass printing), and the mask tables A to D are respectively 102
It is a table of a size corresponding to 4 pixels and 60 pixels in the sub-scanning direction. The number of nozzles used for one print is 240
Therefore, the number of pixels corresponding to the print medium transport amount in 4-pass printing is 240/4 = 60, which is equal to the size of the mask table in the sub-scanning direction.

The basic table generation method is the same as that in the above-described “high image quality mode” in which 8-pass printing is performed by standard driving of the head. Each pass is handled by using the remainder obtained by dividing the value of the original mask table. 1 bit / dot to do
Of tables A, B, C, and D are generated. However, while the divisor is “8” in the “high image quality mode”, which is the same as the number of print passes, the divisor in the “high speed mode” in which 4-pass printing is performed by block distributed division driving is the number of print passes. Instead of "4", "1/2" which is 1/2 of the value is selected as the divisor. In other words, using the remainders “0” and “1” obtained by dividing the value of the original mask table by “2”, two tables A and C are generated that generate “1” indicating a non-mask corresponding to each. . The duties of A and C are almost equal, and are about 50%. Tables B and D are tables having the same contents as tables A and C, respectively. The table created in this way is table A (=
B) and table C (= D) are complementary,
Exactly the same path data is generated in the first pass and the second pass or in the third pass and the fourth pass. FIG. 17 shows an example of a mask table for each print scan generated in this manner.

FIG. 18 is a view for explaining a form of print scanning using the mask table shown in FIG.
The contents of the tables A, B, C, and D are applied as mask patterns every 60 lines to the data of 240 lines corresponding to the 240 used nozzles. All image areas are always subjected to mask processing in the order of A, B, C, and D to generate print data. Table A,
If mask processing is sequentially performed by B, C, and D, an image for 200% is formed (all print dots are formed twice), but this is avoided by a combination with a drive mask.

FIG. 19 shows an aspect of a mask operation for print data performed using the final mask formed by applying the mask table shown in FIG. 17 and the driving mask shown in FIG. 15A or 15B. FIG.

For data of 240 lines corresponding to 240 used nozzles, tables A, B,
C and D are applied as mask patterns. In the mask processing in each print scan, in addition to each mask table, a drive mask S or T by block distributed division driving is substantially applied. Thus, the final mask corresponding to four print scans is AS, BT, C
A region having the order of S and DT and a region having the order of AT, BS, CT and DS are alternately present. But,
Here, the tables A and B, the tables C and D are equal, and the tables A (or B) and C (or D) and the drive masks S and T are complementary (total of 100% duty). Therefore, in any case, it is possible to form a print dot with a duty of 100% in four scans. Similarly, even if the driving masks S and T change due to the difference in the area around the nozzle used in the sub-scanning direction registration process, the dot forming order is different in a minute point, but the scanning is performed four times. 1
It is still possible to form 00% of print dots.

Although the case where four-pass printing is realized by block distributed division driving in the "high-speed mode" has been described above, a very similar processing flow is performed in the "standard mode" in which eight-path printing is performed by block distributed divided driving. Becomes

That is, in this case, “4”, which is の of the number of print passes, is selected as the divisor at the time of table generation, and the remainder is set to “0”, “1”, “2”, or “3”. The four tables A, C, which generated "1" indicating a non-mask
Create E and G. Tables B, D, F, and H are the same tables as tables A, C, E, and G, respectively. The table created in this way is the table A (= B)
, Table C (= D), table E (= F), and table G (= H) are complementary, but a pair of continuous scans (a pair of first and second scans, a pair of third and Exactly the same pass data is generated in the four scan pairs, the fifth and sixth scan pairs, and the seventh and eighth scan pairs.

In the mask processing in each print scan, in addition to the mask table, a driving mask by block distributed division driving is substantially applied. As a result, a print dot with a duty of 100% can be formed by eight print scans. However, the print medium conveyance amount in 8-pass printing is 30 lines, which is not a multiple of the sub-scanning direction size 4 of the driving mask. Therefore, scanning s and scanning t are repeated alternately as in 4-pass printing. In this case, 100% area cannot be driven by continuous scanning. In other words, in the scanning t, the driving mask T shown in FIG. 15B is shifted by two pixels in the sub-scanning direction (vertical direction in the drawing), and as a result, the driving mask T becomes equivalent to the driving mask S.

Therefore, in practice, the control unit 208 always sends (S0, S1) = (S0, S1) to the head control block 622.
A combination of (0, 1) is used, and a scan s for driving the even-numbered block and the odd-numbered block is always executed, so that the drive masks S and T appear alternately. In this way, by performing print dot formation by logical product of the drive mask based on whether or not the print head can be driven and the print dot mask processing by the mask table, efficient pass data generation processing and reduction of the scale of memory and the like are performed. And cost reduction can be realized.

In addition to the block dispersion division driving method in which the driving mask shown in FIGS. 15A and 15B is formed by the driving method shown in FIGS. Similarly, in a system having a 50% drivable duty, for example, a system in which all blocks are driven every other row, image formation can be performed using the same mask table. This means that a common mask table generation process can cope with a head driving method (or a combination thereof) having the same drivable duty in each scan, which is a very flexible and effective method. It can be said.

As described in detail above, in the case of employing a print head driving method capable of driving only coordinate positions (print dots) limited in a single print scan, as represented by block dispersion division driving, etc. In consideration of completing the image by the logical product of the drive mask and the path data accompanying the above, by generating a mask table for generating the path data, the shift of the print use nozzle area in the mounting nozzles is performed. However, the same table can be used by the same generation processing, so that the mask table generation processing can be simplified and speeded up, and further, the cost can be reduced by using a common mask table for each ink color.

2) Second Embodiment In the first embodiment, the "high image quality mode" in which 8-pass printing is performed by the block standard division drive (carriage low speed) and the 8 in the block dispersion division drive (carriage high speed). The inkjet printing apparatus has three print modes, a "standard mode" for performing pass printing and a "high-speed mode" for performing four-pass printing by block dispersion division drive (carriage high speed), and performs one-way printing in all cases. . In the second embodiment of the present invention, an ink jet printing apparatus that performs reciprocal printing (bidirectional printing) in order to achieve an improvement in throughput will be described. explain.

First, registration processing in the sub-scanning direction in reciprocal printing will be described. The relative displacement of a plurality of ejection sections corresponding to each ink color due to a mounting error of the print head is different from that in the forward scan. It does not always coincide with the backward scan. This is mainly because the carriage on which the print head is mounted tilts during scanning, and the degree and direction of the tilt differ depending on the scanning direction. This means that when focusing on one ejection unit, the adjustment values of the registration for the forward scan and the backward scan take independent values, that is, the adjustment values of the registration may be different between the forward scan and the backward scan. means.

If the used nozzle area in the mounting nozzle is different between the forward scan and the backward scan, the same drive mask (scan s or scan t) is not obtained even when the same drive (scan s or scan t) is performed in the forward scan and the backward scan. Therefore, even if the scan s and the scan t are alternately performed as in the “high-speed mode” in the first embodiment, complementary driving is performed in the first pass (for example, the forward pass) and the second pass (for example, the return pass). It does not act as a mask, so that it is impossible to form print dots with a duty of 100%.

In order to avoid this, in the present embodiment, the output of the mode switching signals (S0, S1) is appropriately controlled, so that the scanning order is changed twice so as to be alternately switched. For example, by repeating the scanning s, the scanning s, the scanning t, the scanning t, the scanning s, the scanning s, the scanning t, and the scanning t in this order, the forward path always exists only twice in four scans for all the regions. Different scans s or t are performed for the scan (or the backward scan).
The drive masks for the scans s and t in accordance with the adjustment values of the sub-scanning direction registration in the forward scan are Sf and Tf, respectively, and the scan masks for the scans s and t in accordance with the adjustment values of the sub-scanning direction registration in the backward scan. Assuming that the driving masks are Sb and Tb, respectively, the driving masks Sf, Sb, Tf,
The regions in the order of Tb and the driving masks Sb, Tf, Tb,
The regions in the order of Sf and the driving masks Tf, Tb, Sf,
The regions in the order of Sb and the driving masks Tb, Sf, Sb,
And the regions in the order of Tf are repeatedly present. In all cases (areas), 100% areas can be driven by the first pass and the third pass, and the second pass and the fourth pass. In this way, the invention can be extended to reciprocal print scanning.

FIG. 20 shows a print scanning mode in which mask processing of image data using a mask table is performed, and a substantial mask (drive mask) is applied by driving the print head. In other words, by performing print dot formation by logical product of a drive mask based on whether or not the print head can be driven and a print dot mask process by the mask tables A to D, an efficient pass data generation process and a scale of a memory or the like are achieved. Cost reduction by reduction can be realized.

As described above, complementary driving is performed for each of a plurality of print scans in each of the forward and backward scan directions, and the arrangement of the mask table in the sub-scan direction is correspondingly performed. By changing, the same as unidirectional printing in round-trip printing,
Simplifying and speeding up the mask table generation process,
Cost reduction can be realized by using a common mask table for each ink color. Note that here, "High-speed mode"
Has been exemplified in the case of performing reciprocating printing, but it is needless to say that the present embodiment can be applied to other modes.

(Other Embodiments) In the first and second embodiments described above, the coordinate position (print dot position) on the surface of the print medium in a single print scan.
As an example of a method of driving by limiting a part of FIG.
Although the block distributed division driving shown in (A) and (B) has been described, the present invention is not limited to this. As described in the first embodiment, the same mask table generation method can cope with a method in which the drivable area in each print scan has the same duty. Further, it is apparent that the present invention can be extended to a case where the drivable area duty in each print scan is not 50%. Also, as for the pass data generation method, an example has been described in which a table mask method of generating pass data by masking image data with a mask table is used. All pass data generation methods, such as a fixed mask method that sorts print dots in rows or in a zigzag pattern, a data mask method that sorts print dots by focusing on only print dots, and a combination of these methods Can also be applied. The table size in the table mask method is not limited to the above embodiment.

Further, in the above-described two embodiments, the ink tank in which the four color inks are respectively enclosed is provided.
Independent 4 having the form of a so-called multi-nozzle head corresponding to each and having a large number of nozzles integrated therein
The case where the print head constituted by the three ejection units is used has been described. However, the ink colors are not limited to four colors, and light cyan (LC)
A configuration using a plurality of inks having different densities, such as y) and light-color inks such as light magenta (L-Mg), may be used. Further, the number of mounted nozzles is not limited to 256, and the number of nozzles used for image formation is not limited to 240. Further, the ink jet printing apparatus for printing one dot per pixel for each ink color has been described, but an ink dot may be superimposed on substantially the same pixel.

Further, the print head to be mounted is not limited to the one having one discharge unit for each color for the four colors as described above, and a plurality of sets of print heads corresponding to two or more discharge units for each color are provided. The present invention is also applicable to an equipped inkjet printing apparatus.

FIG. 21 is a schematic diagram showing a configuration example of a printing unit of an ink jet printing apparatus equipped with two sets of print heads. The carriage 302 has a first print head 301 and a second print head 307 mounted thereon, and has six colors (Bk, Cy, Mg, Ye, LC), respectively.
(y, L-Mg) ink.

FIG. 22 is a diagram showing an example of the arrangement of the ejection sections of the two sets of print heads. In this example, the arrangement of the ink colors is symmetrical. In this case, the mask table can also realize a function of distributing print dots to two sets of print heads.

Further, the form of the ink jet printing apparatus according to the present invention is not limited to the one provided integrally or separately as an image output apparatus of an information processing apparatus such as a computer or a word processor, but a copying apparatus combined with a reading apparatus. Or a facsimile machine having a communication function.

Further, the ink ejection section employed in the print head is used to generate energy used to eject ink, such as an electrothermal transducer (ejection heater) or an electric pressure transducer (piezo element). Of the above-described devices.

[0097]

As described in detail above, according to the present invention, an ejection section having a plurality of ejection ports for ejecting ink is used, and the ejection section is arranged with the plurality of ejection ports. The scanning is performed a plurality of times in a direction different from the scanning direction, and during each scanning, the printing medium is relatively conveyed in a direction orthogonal to the scanning direction by an amount smaller than the arrangement width of the plurality of ejection ports, so that the same printing medium is scanned. In forming an image using a different ejection port for an area, a mask process is performed on the image data so that a part of the image data relating to printing is in a non-printing state in order to perform image formation by the plurality of scans. Of the masked data and a pattern determined in accordance with a driving mode to cause the plurality of ejection ports to perform limited ink ejection in accordance with a position in a print area. A mask by driving only a limited coordinate position represented by block dispersion division drive or the like in a single print scan by driving the ejection unit based on In addition, by forming a dot necessary for each print scan by logical AND with a mask by replacing a print dot included in image data with a non-print dot, a sub-scan direction registration process is performed. Regardless of the selection state of the used nozzle from the plurality of nozzles mounted in the scanning direction, a single mask table by a single generation process can be used, which simplifies and speeds up the mask table generation process, and furthermore, An excellent effect that enables cost reduction by sharing a mask table for all ink colors, etc. Exhibit.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of a mask table for each print scan.

FIG. 2 is an explanatory diagram for explaining a print scanning mode using the mask table shown in FIG. 1;

FIG. 3 is a schematic diagram illustrating a print head that discharges ink from a discharge port side.

FIG. 4 is an explanatory diagram for explaining a standard block division driving mode for a print head having the nozzle arrangement shown in FIG. 3;

FIG. 5 is an explanatory diagram showing an example of allocating nozzles included in each block that is divided and driven as shown in FIG. 4;

FIG. 6 is an explanatory diagram for explaining a mode of block distributed division driving for a print head having the nozzle arrangement shown in FIG. 3;

FIG. 7 is an explanatory diagram showing dot positions (coordinates) that can be driven in a single scan of the block distributed division drive in FIG. 6;

FIG. 8 is an explanatory diagram for describing an inconvenience that may occur when block distributed division driving is performed on a configuration corresponding to a predetermined sub-scanning direction registration process.

FIG. 9 is a schematic diagram illustrating a configuration example of a printing unit of an inkjet printing apparatus to which an embodiment of the present invention can be applied.

10 is a block diagram illustrating a schematic configuration example of an overall control circuit of the inkjet printing apparatus illustrated in FIG.

FIGS. 11A and 11B are schematic configuration examples of a pass data generation processing system for generating print data for each print scan in multi-pass printing according to an embodiment of the present invention; FIG. 4 is a functional block diagram and an explanatory diagram showing correspondence between contents of a mode switching signal and a drive mode or a drive mode of a print head.

FIG. 12 is a diagram illustrating an example of a mask table for each print scan used in a “high image quality mode” in which 8-pass printing is performed by standard head driving according to an embodiment of the present invention.

FIG. 13 is an explanatory diagram for describing a print scanning mode in a “high image quality mode” using the mask table shown in FIG. 12;

FIGS. 14A and 14B are explanatory diagrams for describing block dispersion division driving performed in a “standard mode” and a “high-speed mode”.

FIGS. 15A and 15B are explanatory diagrams for describing a drive mask used in the block distribution division drive shown in FIGS. 14A and 14B.

FIG. 16 is an explanatory diagram for explaining a use state of a drive mask for each print scan in a “standard mode” and a “high-speed mode”.

FIG. 17 is a diagram illustrating an example of a mask table for each print scan used in a “high-speed mode” in which four-pass printing is performed by block distributed division driving according to an embodiment of the present invention.

FIG. 18 is an explanatory diagram for explaining a print scanning mode in the “high-speed mode” using the mask table shown in FIG. 17;

19 is a diagram showing the mask table shown in FIG. 17 and FIG.
FIG. 9 is a diagram for explaining a mode of a mask operation for print data performed using a final mask table formed by applying the drive mask shown in FIG.

FIG. 20 is an explanatory diagram for explaining an aspect of print scanning according to another embodiment of the present invention.

FIG. 21 is a schematic diagram illustrating a configuration example of a printing unit of an inkjet printing apparatus to which still another embodiment of the present invention can be applied.

FIG. 22 is a diagram showing an example of an arrangement of ejection units of two sets of print heads used in the configuration of FIG. 21;

[Explanation of symbols]

 201 memory unit 202 input control unit 203 output control unit 204 table storage unit 205 mask processing unit 206 original table storage unit 207 table generation unit 208 control unit 301, 307 print head 302 carriage 303 transport roller 306 print medium 605 interface 624 host device 601 CPU 602 ROM 603 EEPROM 604 RAM 608 Output port 610 Carriage motor control circuit 611 Carriage motor 613 Transport motor control circuit 614 Transport motor 612 Transport mechanism 621 Print head control circuit 622 Head control block 619 Power supply circuit 607 Operation keys 606 Input port 609 Output port 615 LED control circuit 617 Display control circuit 618 LCD 623 CPU bus

Claims (12)

[Claims] 1. An ejection unit having a plurality of ejection openings for ejecting ink is used, and the ejection unit is scanned a plurality of times in a direction different from the arrangement direction of the plurality of ejection openings. By transporting the print medium relative to each other in a direction orthogonal to the scanning direction by an amount smaller than the arrangement width of the plurality of discharge ports, a different discharge port is used for the same area on the print medium. An ink-jet printing apparatus for forming an image, wherein the image data is subjected to a masking process for setting a part of the image data relating to printing to a non-printing state so as to perform the image formation by the plurality of scans. A data output unit, and a driving mode for causing the plurality of ejection ports to perform limited ink ejection according to the position of the masked data and a print area. Based on the logical product of the determined pattern Flip, ink jet printing apparatus being characterized in that comprises a means for forming an image by driving the discharge portion. 2. The data output means includes: means for storing a table of mask data used for performing the mask processing; and mask processing means for performing mask processing on the image data with reference to the table. The inkjet printing apparatus according to claim 1, wherein: 3. The discharge section is divided into a plurality of blocks each including a plurality of discharge port groups, and as the driving mode, a part of the plurality of blocks is arranged for each column in a single scan. The inkjet printing apparatus according to claim 1, wherein the inkjet printing apparatus is selectively driven. 4. A mode for selectively driving a part of the plurality of blocks in the single scan and a mode for driving all of the plurality of blocks.
5. The inkjet printing apparatus according to claim 1. 5. The ink jet printer according to claim 1, wherein the discharge section has an element for generating thermal energy for causing film boiling of the ink as energy used for discharging the ink from the discharge port. An inkjet printing apparatus according to any one of the above. 6. The ink jet printing apparatus according to claim 1, wherein the discharge unit has an element for applying the energy used for discharging the ink from the discharge port to the ink. . 7. An ejection section having a plurality of ejection ports for ejecting ink, wherein the ejection section is scanned a plurality of times in a direction different from the direction in which the plurality of ejection ports are arranged. By transporting the print medium relative to each other in a direction orthogonal to the scanning direction by an amount smaller than the arrangement width of the plurality of discharge ports, a different discharge port is used for the same area on the print medium. An image forming method for forming an image, comprising outputting, to the image data, data obtained by performing a mask process for setting a part of image data relating to printing to a non-printing state in order to perform image formation by the plurality of scans. A data output step to be performed, the masked data, and a position determined in a print area in accordance with a driving mode for causing the plurality of discharge ports to perform limited ink discharge. Based on the logical product of the pattern, an image forming method characterized by equipped with a step of forming an image by driving the discharge portion. 8. The method according to claim 7, wherein in the data output step, mask processing is performed on the image data by referring to a table of mask data used for generating the image data with reference to the table. Image forming method. 9. The discharge unit is divided into a plurality of blocks including a plurality of discharge port groups, and as the driving mode, a part of the plurality of blocks is arranged for each column in a single scan. 9. The image forming method according to claim 7, wherein the image forming apparatus is selectively driven. 10. The image according to claim 9, further comprising a mode for selectively driving a part of the plurality of blocks and a mode for driving all of the plurality of blocks in the single scan. Forming method. 11. The ink jet printer according to claim 7, wherein the discharge unit has an element for generating thermal energy for causing film boiling of the ink as energy used for discharging the ink from the discharge port. The image forming method according to any one of the above. 12. The ink jet printer according to claim 7, wherein the discharge unit has an element for applying energy to the ink as energy used for discharging the ink from the discharge port.
0. The image forming method according to any one of the above.