JP2000141715A - Recording method and recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering of image quality due to variation of a quantity of ejected ink by a method wherein a pseudo-intermediate operation and a resolution converting operation with respect to multi-value image data are executed in a real time basis and rising of a temperature of a recording head is suppressed. SOLUTION: Inputted multi-value image data is converted to dot data that is provided with pseudo-gradation conversion and resolution conversion by looking up a memory. The number of dots recorded by one scanning for recording based on the dot data is counted (S103, S104). A temperature of the recording head is estimated from the counted value (S106). It is determined whether or not the next recording is executed by one time scanning for recording or plural times of scannings for recording (S108, S109) in accordance with the estimated temperature of the recording head (S107).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method and apparatus for recording multi-valued image data and recording an image by a plurality of relative recording scans (multi-pass).

[0002]

2. Description of the Related Art In recent years, various printer devices have been widely used as output terminals of personal computers and the like. Some of such printers have a significantly higher resolution than the resolution of a display device such as a CRT or a liquid crystal, and many printers that exceed the resolution (resolution) of image data used in a host computer or the like have been developed. Have been.

By the way, in an apparatus for recording an image composed of a dot pattern on a recording medium, not limited to an ink jet recording apparatus which performs recording by an ink jet method, image data is thinned out and scanned by a plurality of scans (or passes). A printing method that is completed, that is, a so-called multi-pass printing is employed.

Such multi-pass printing not only reduces the power consumption of the power supply device by reducing the energy consumption of the print head in one print scan, but also reduces the cost of the power supply device. (Record element)
This is adopted for the purpose of reducing deterioration of image quality due to density unevenness caused by variation in the amount of ink ejected from the printer. For example, according to the method described in JP-A-59-16765, one scan (scan of the recording head)
Is calculated based on the total number of dots that can be printed and the number of dots to be printed, and if this duty is greater than or equal to a predetermined value corresponding to the capacity of the power supply, the scan is performed in one scan. Divide the number of elements to be driven into multiple
It describes that an image is printed by a plurality of printing scans.

[0005]

By the way, in a recording apparatus for recording an image consisting of a dot pattern on a recording medium, the dot size formed on the recording medium must be constant, and the image formed by a group of dots must be formed. Performances such as stable density, good gradation reproducibility, and good color reproducibility in a color printing apparatus are required. In particular, in an ink jet recording apparatus that discharges ink by using thermal energy, the ink discharge amount fluctuates due to the environmental temperature and the self-heating of the recording head due to the heat generation drive for ink discharge. Greatly affects various performances.

For example, Japanese Patent Application No. Hei 5-89791 discloses a temperature sensor provided on a print head and data on the temperature rise of the print head obtained from a dot counter for counting the number of ejection dots. A PWM driving method has been disclosed in which the ejection pulse amount is stabilized by changing the driving pulse width of the recording head based on the driving pulse width. Japanese Patent Application Laid-Open No. Hei 5-208505 discloses a method for calculating the temperature fluctuation of a printhead accurately at high speed based on the energy input to the printhead.

[0007] However, this Japanese Patent Application No. Hei 5-89791 is disclosed.
Patent Publication No. JP-A-2006-133556 discloses a PWM that stabilizes an ink ejection amount by changing a driving pulse width of a recording head.
In the driving method, when the self-temperature rise due to ink ejection for printing is large, such as when printing data in which the total number of dots to be printed in one main scan is large (duty is high). Was not very effective.

Japanese Patent Application Laid-Open No. 60-107975 discloses that the number of dots recorded by one nozzle in one scan is about one half of prescribed image data according to a predetermined image data arrangement. A multi-pass printing method is disclosed in which an image is completed by printing the remaining dots in the second scan. Further, Japanese Patent Application Laid-Open No. 7-52389 discloses that in multi-pass printing, a plurality of types of image data arrays for thinning out prescribed image data are prepared, and the pattern cycle of the thinning is changed to reduce the image quality deterioration due to density unevenness. A reduction approach is disclosed. According to this, since the total number of dots printed in one main scan is reduced, the effect of self-heating caused by ink ejection for printing is reduced, and performance such as density stability can be secured.

However, when multi-valued image data is input,
The multi-valued image data is subjected to pseudo gradation conversion processing with reference to a table or the like, and based on the result of resolution conversion, the above-mentioned Japanese Patent Application Laid-Open No. 60-107975 or Japanese Patent Application Laid-Open
In the case of performing multi-pass printing disclosed in Japanese Patent No. 389, 389, in order to adopt the technology disclosed in these publications, in real time, in synchronization with the movement of the carriage, for example, every (1/1200) inch. Control became necessary, and such control was extremely difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and performs a pseudo halftone process and a resolution conversion process on multi-valued image data in real time, suppresses a rise in the temperature of a recording head, and performs ink conversion. It is an object of the present invention to provide a recording method and a recording apparatus which can effectively reduce the deterioration of image quality due to the variation of the ejection amount.

It is another object of the present invention to provide a recording apparatus in which the most recently recorded
The current print head temperature is estimated based on the number of dots in the print scan, and based on the estimated temperature, whether the next print scan is performed by a plurality of print scans or by one print scan is performed. An object of the present invention is to provide a recording method and apparatus capable of recording a high-quality image while suppressing a rise in the temperature of the recording head.

[0012]

In order to achieve the above object, a recording apparatus according to the present invention has the following arrangement. That is, a printing apparatus for printing by relatively moving a print head having a plurality of print elements with respect to a print medium, and holding means for holding input multi-valued image data, read from the holding means A memory for converting multi-valued image data into dot data; inputting the multi-valued image data to an address of the memory and converting the multi-valued image data into dot data based on data read from the memory; Conversion means for converting, a counting means for counting the number of dots printed by the printing scan by the relative movement of the printing head, and a temperature for estimating the temperature of the printing head based on the count value counted by the counting means. Estimating means, printing control means for printing an image by one printing scan or a plurality of printing scans according to the temperature estimated by the temperature estimating means, At the time of printing by several printing scans, conversion control means for changing the dot data between a first printing scan and a second printing scan of the printing head, and dot data obtained under the control of the conversion control means. And a drive control means for outputting and driving corresponding to a plurality of print elements of the print head.

To achieve the above object, the recording method of the present invention comprises the following steps. That is, a printing method in a printing apparatus for printing by moving a printing head having a plurality of printing elements relative to a printing medium, wherein the multi-level image data is input to a memory address for converting the data into dot data. A conversion step of inputting the multi-valued image data and converting the multi-valued image data into dot data based on data read from the memory, and calculating the number of dots recorded by recording scan by relative movement of the recording head. A counting step of counting, a temperature estimating step of estimating the temperature of the recording head based on the count value counted in the counting step,
According to the estimation result in the temperature estimating step, a recording control step of recording an image by one recording scan, or a plurality of recording scans, and when recording by the plural recording scans, the dot data is A conversion control step of changing between the first print scan and the second print scan of the print head;
A drive control step of outputting and driving the dot data converted in the conversion control step in correspondence with the plurality of printing elements of the printhead.

[0014]

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

First, the basic configuration and operation of the ink jet recording apparatus according to the present embodiment will be described in detail with reference to FIGS.

FIG. 1 is a schematic view mainly showing the configuration of a recording section of an ink jet recording apparatus according to the present embodiment.
An inkjet head 111 having a resolution of dpi is provided.

In FIG. 1, reference numeral 111 denotes an ink jet head (recording head);
2, 103 and 104. Recording head 1
In each of Nos. 01 to 104, for example, 64 discharge ports are provided on the surface facing the recording paper 7 as the recording medium along the transport direction of the recording paper 7 (the sub-scanning direction indicated by A in the drawing). (Nozzle) is 600 dpi (dot /
Inches). Here, for example, the recording head 101 is a cyan head, the recording head 102 is a magenta head, the recording head 103 is a yellow head, and the recording head 104 is a black head.

The ink jet head 111 is mounted on the carriage 2, and the carriage 2 is slidably engaged with a pair of guide rails 3 extending in parallel with the recording surface of the recording paper 7. With this configuration, the ink jet head 111 can move along the guide rail 3, and discharge ink from the ink jet head 111 at the timing described later with the movement of the carriage 2 in the direction of arrow B. , Host computer 200
The image is recorded on the recording paper 7 based on the recording data sent from. After printing by one scan of the inkjet head 111 is completed, the printing paper 7 is conveyed by a predetermined amount (printing width) in the direction of arrow A (sub-scanning direction), and printing is started again. By repeating this series of operations (referred to as printing scan), printing is sequentially performed on the printing paper 7.
In the present embodiment, it is assumed that printing is performed by discharging ink every (1/1200) inch (that is, resolution of 1200 dpi) in the moving direction of the carriage 2 (referred to as the main scanning direction).

The recording paper 7 is conveyed by rotating a pair of conveying rollers 4 and 5 disposed above and below the recording surface. Also, the recording paper 7
A platen for maintaining the flatness of the recording surface is disposed on the back side of the recording surface.

Further, the movement of the carriage 2 is performed, for example, when the belt 6 attached thereto is moved by the carriage motor 2.
It becomes possible by being moved by the rotation of 0,
Similarly, the rotation of the transport rollers 4 and 5 can be achieved by transmitting the rotation of the paper feed motor 50 to them.

FIG. 3A shows the configuration of the ink jet head 111 as viewed from the recording paper 7 side. Reference numeral 101 denotes a recording head for discharging cyan ink (C), and similarly, reference numeral 102 denotes a magenta ink. A recording head for discharging ink (M), 103 is a recording head for discharging yellow (Y) ink, and 104 is a recording head for discharging black (K) ink.

FIG. 3B shows recording heads 101 to 1.
FIG. 4 is an enlarged view showing a surface of each of the recording papers 04 facing the recording paper 7.

In FIG. 3B, 64 discharge ports (N
63-N0) is of course equivalent to 600 dpi. Each of these recording heads 101 to 104 has
An ink path or a processing liquid path communicating with each of the 64 nozzles is provided, and thermal energy for discharging ink onto a substrate constituting the recording heads 101 to 104 is provided in correspondence with those flow paths. Is formed. These electrothermal transducers generate heat by an electric pulse applied in accordance with drive data, cause the ink to generate film boiling by the generated heat, and eject the ink from the nozzles by generating bubbles due to the film boiling. .
Further, in the recording heads 101 to 104, each of the flow paths communicating with the discharge ports is provided with a common liquid chamber commonly communicating with the flow path, and the ink or the processing liquid is supplied from the common liquid chamber in accordance with the discharge operation. It is supplied to each channel.

FIG. 2 is a block diagram showing a configuration of a control system in the ink jet recording apparatus shown in FIG.

The CPU 100 executes control processing for operating each unit and data processing for recording.
The OM 100A stores the processing procedure and the like.
Further, the RAM 100B is used as a work area for executing various processes performed by the CPU 100.

The recording data transferred from the host computer 200 is received by the CPU 100 and then stored in the image memory 222A. Subsequently, the drive data generation unit 222 reads out the print data stored in the image memory 222A based on an instruction from the CPU 100, and generates drive data for actually driving each of the print heads 101 to 104. The driving data is supplied to the driver circuit for each head of the head driver 111A. In accordance with the supplied drive data, the head driver 111A applies an electric pulse to the inkjet head 111 to cause each nozzle of each recording head to eject ink. The CPU 100 includes a carriage motor 20 for moving the carriage 2 and a paper feed motor 50 for rotating the transport rollers 4 and 5.
Is controlled via the motor drivers 20A and 50A.

In this embodiment, as shown by the pixel data 401 in FIG.
00, the size of one pixel is (1/300) inch square (that is, resolution 300 dpi × 300 dpi), and C,
It is assumed that print data of 4 bits (that is, 16 gradations) is transmitted for each color of M, Y, and K. Here, pseudo halftone processing and resolution conversion processing are performed for each recording data of each color, so that one dot is in the main scanning direction (1/1200) inch.
In the sub scanning direction (1/600) inch (that is, resolution 120
0 dpi × 600 dpi), and 1 for each color of CMYK
Driving data (4011-4) corresponding to the original one pixel data 401 represented by one bit per dot (that is, two gradations)
018), and recording is performed based on the drive data.

FIG. 4B shows the host computer 200.
, Pixel data 402 of one pixel (4 bits) having a pixel value of “8h” (“h” indicates a hexadecimal number)
(Resolution 300 dpi × 300 dpi) is the driving data (dot resolution 120
FIG. 9 is a diagram illustrating an example in which the drive data 403 is composed of 0 dpi × 600 dpi) and is converted into drive data 403 including 8 dots. In the converted drive data 403, the value is “1”.
h ”dot (represented by a black circle“ ● ”) 40
At positions 32, 4033, 4036, and 4037, ink is ejected, and dots whose values are "0h" (represented by white circles ") 4031, 4034, and 403"
In 5, 4038, ink is not ejected.

Here, various methods have been proposed as methods of the pseudo halftone processing and the resolution conversion processing. In the present embodiment, the recording data (4 bits per pixel) transmitted from the host computer 200 is transmitted from the host computer 200. Resolution 300dp
i × 300 dpi) is converted to 8 bits using drive data (resolution: 1200 dpi × 600 dpi) represented by 1 bit per dot prepared in advance in accordance with the value, and a pseudo-reference method is used to refer to a table. Halftone processing and resolution conversion processing are performed simultaneously. still,
Hereinafter, the previously prepared drive data represented by 8 bits (resolution 1200 dpi × 600 dpi), that is, a set of 8 dots will be referred to as a pattern.

FIGS. 5A to 5C show data of 4 bits per pixel (resolution 300 dpi.times.) In this embodiment.
FIG. 4 is a diagram illustrating an example of a correspondence relationship between an 8-bit pattern (dot resolution: 1200 dpi × 600 dpi) and an 8-bit pattern (300 dpi).

In FIG. 5A, with respect to pixel data 501 having a value of “0h”, patterns 501C (for cyan), 501M (for magenta), and 501M (for magenta) in which no ink is ejected are respectively applied to CMYK. 501Y (for yellow) and 501K (for black) are allocated.

As shown in FIG. 5B, when the value is "E
For the pixel data 515 of "h", patterns 515C, 515M, 515Y, and 515K in which ink is ejected at positions of six dots out of eight dots of one pattern.
Are assigned to the respective colors. Here, in the patterns 515C, 515M, 515Y, and 515K, the number of dots on which ink is ejected is the same, but the positions of dots on which ink is ejected are different for each of the colors CMYK.

Further, as shown in FIG.
For the pixel data 516 of "h", patterns 516C, 516M, 516Y, and 516K in which ink ejection is performed at all dot positions of one pattern for each of CMYK colors.
Is assigned.

FIG. 6 shows C (cyan) pixel data (resolution: 300 dpi × 300 dpi) of 4 bits per pixel sent from the host computer 200, and FIG. As a result of performing the pseudo halftone processing and the resolution conversion processing based on the correspondence shown in c), cyan drive data composed of an 8-dot (8-bit) pattern (resolution 1200 dpi × 600)
dpi), and the generated drive data and 64 ejection ports (nozzles: N0 to N0) of the print head 101.
N63).

In FIG. 6, similarly to FIG. 5, pixel data having a pixel value of "0h" is indicated by 501, a corresponding pattern is a pattern 501C, and a pixel value is "Eh".
Are denoted by 515, the corresponding pattern is denoted by a pattern 515C, the pixel data having the pixel value “Fh” is denoted by 516, and the corresponding pattern is denoted by a pattern 516C.

In the present embodiment, the pseudo halftone processing and the resolution conversion processing by referring to the table described above are performed by C
The configuration is such that the processing is executed in real time in synchronization with the movement of the carriage 2 every (1/1200) inch, instead of off-line processing by the PU 100 or the like. This is because the amount of data to be processed has increased remarkably due to the high resolution of the inkjet recording apparatus according to the present embodiment. This is because it is desired to avoid an increase in cost caused by providing the memory 222A.

In the present embodiment, the driving data generation unit 222 shown in FIG. 2 performs the pseudo halftone processing and the resolution conversion processing in real time, and FIG.
FIG. 2 is a block diagram for explaining an internal configuration of the device.

The read address control unit 701 includes CMYK
The four registers, one for CMYK and one for CMYK, are included for holding the addresses for reading the print data corresponding to the respective color inks from the image memory 222A.

In FIG. 7, reference numeral 701 denotes a read address control unit which controls the entire operation of the drive data generation unit 222.
From the drive data control unit (not shown), (1/1200) dpi
Signal PRTRG supplied for each (head scanning resolution)
Then, from the read addresses stored in the register corresponding to each color, an address storing print data corresponding to the color to be processed is selected and supplied to the address counter 702. A load signal RDTRG for causing the address counter 702 to hold the start address STRTAD [17: 0] is generated. continue,
At a predetermined timing, a clock signal CLK for address increment for the address counter 702 is generated.
The read address IMGAD [1
9: 0] is supplied. At this time, the read address IMGAD [19: 0] supplied from the address counter 702 to the image memory 222A is supplied from the lower 18 bits [17: 0] of the count output of the address counter 702 and the read address control unit 701. 2 bit signal COLO
This is a signal of 20 bits [19: 0] in total, where R [1: 0] is the upper two bits [18:19].

The signal COLOR [1: 0] is a signal indicating the color of the data to be processed. If the value is "0h", the processing of the cyan (C) color is performed. If the value is "1h", the magenta (M) ), Yellow (Y) if "2h",
“3h” indicates that the processing is black (K).

The image memory 222A is an image memory having a storage capacity of a total of 1024K words with 4 bits as one word. The input address is 20 bits and the output data is 4 bits.

FIG. 8 shows a resolution 300 dpi × 300 dpi transferred from the host computer 200 and C
FIG. 9 is a diagram illustrating how 4-bit data for each color of MYK is stored in an image memory 222A.

As is apparent from FIG. 8, in the present embodiment, the address "00000" of the image memory 222A is used.
h ”to“ 3FFFFh ”are storage areas for C (cyan) data, and addresses“ 40000h ”to“ 7FFFFh ”are stored.
FFh ”to the storage area of M (magenta) data, and addresses“ 80000h ”to“ BFFFFh ”to Y
(Yellow) data storage area, address "C0000"
h ”to“ FFFFFFh ”are storage areas for K (black) data.

Returning to the description of FIG.
Is a memory that stores 8-bit pattern data to be output corresponding to pixel data of each color, as described in FIG. This memory 703 stores 4-bit pixel data COD output from the image memory 222A.
E [3: 0] is the lower 4 bits, and a signal C indicating the color to be processed
An address signal MAD [5: 0] consisting of a total of 6 bits, with OLOR [1: 0] being the upper 2 bits, is supplied. The memory 703 is a memory for performing the pseudo halftone processing and the resolution conversion processing by referring to the table described above in real time, and has an input address of 6 bits and output data of 8 bits.
It is assumed that the CPU 100 has previously written the 8-bit pattern data shown in FIG. 4B or FIGS. 5A to 5C by the CPU 100.

FIG. 9 shows the state shown in FIG. 4B and FIG.
The pattern data shown in FIG.
It is a figure showing whether it is stored in 03.

In FIG. 9, 1 whose pixel value is "0h"
4-bit pixel C data (resolution 300 dpi x 300
pattern C0 (501C) assigned to dpi)
Are the drive data (501C1 to 501C) of 8 bits (1 dot / 1 bit) constituting the pattern 501C.
8) (resolution 1200 dpi × 600 dpi) as shown in FIG.
Are stored at the address “00h” of the memory 703 in a format arranged as shown by 901C. A pattern M0 (501M) assigned to 4-bit M data of one pixel having a pixel value of “0h” is the same as 901 in FIG.
It can be read that the data is stored at the address “10h” of the memory 703 in a format arranged as indicated by M.

In this embodiment, as shown in FIG. 10, the addresses “00h” to “0Fh” of the memory 703 correspond to the cyan pattern C0 to the pattern C0.
15 storage areas, from address “10h” to “1F”
h ”is the magenta pattern M0 to the pattern M15.
The addresses "20h" to "2Fh" are the storage areas for the yellow patterns Y0 to Y15, and the addresses "30h" to "3Fh" are the storage areas for the black patterns K0 to K15.
It is assumed that each pattern is stored in ascending order of the number from the lowest address of the memory 703.

Returning to the description of FIG. 7, the data output MDT [7: 0] of the memory 703, that is, the data signal for which the pseudo halftone processing and the resolution conversion processing by referring to the table have been completed are output to the 4-1 multiplexer 704, The data is supplied to the data latch group 706 via the 705. Here, the outputs of the multiplexers 704 and 705 are the signals PRT supplied every (1/1200) dpi from the control unit of the drive data generation unit.
A count output signal COLUMN [1: 0] of a 2-bit counter 707 for counting RG is input as a selection signal. That is, these multiplexers 704 and 705
If the value of the output signal COLUMN [1: 0] of the counter 707 is “1h”, the input of the terminal 1 is selected, if “2h”, the input of the terminal 2 is selected, if “3h”, the input of the terminal 3 is selected, and If it is “0h”, the input of the terminal 4 is selected and output to the output terminal Y.

A data latch group 706 to which data from the multiplexers 704 and 705 is supplied is a set of latch circuits for holding recording data to be supplied to the head driver 111A. The data latch group 706 is
It is composed of 64 D-type flip-flops,
Output signals HDT0, HDT1, H of each flip-flop
DT2,..., HDT63 correspond to the nozzles N0, N1, N2,.

As an input of each flip-flop constituting the data latch group 706, an output terminal Y of the multiplexer 704 is provided for the flip-flop corresponding to the nozzle numbers N0, N2, N4,.
Is supplied from the printer and the nozzle number N of each recording head
The data from the output terminal Y of the multiplexer 705 is supplied to the flip-flops corresponding to 1, N3, N5,. In addition, CLK of each flip-flop
As an input, a 32-bit decode signal obtained by decoding an address increment clock signal CLK generated by the read address control unit 701 by a 5-bit counter 708 by a 5-bit decoder 709 is supplied.

As shown in FIG. 7, in this embodiment, output data MDT7, MDT5, MDT3, and MDT1 of the memory 703 are input to the input terminals 1 to 4 of the multiplexer 704, and the input terminals 1 to 4 of the multiplexer 705 are input to the input terminals 1 to 4. Is the output data MDT6, MDT4, MDT of the memory 703
2, MDT0 is supplied. Therefore, MDT7, M
If any of DT5, MDT3, and MDT1 is HDT
0, HDT2, HDT4,..., Are sequentially latched every time the 5-bit counter 708 is counted up by the address increment clock signal CLK.
If any of T4, MDT2 and MDT0 is HDT
, HDT2, HDT4,... Are sequentially latched every time the 5-bit counter 708 counts up by one.

In the present embodiment, in order to generate data for 64 nozzles of the print head, print data having a resolution of 300 dpi.times.300 dpi is processed for 32 pixels of one bit of 4 bits. The unit 701 generates 32 address increment clock signals CLK per color.

In FIG. 7, the 2-bit signal COLOR [1: 0] indicating the color to be processed is decoded by the 2-bit decoder 710, which is the data signal HDT [0: 6].
3] to the head driver 111A to generate a latch signal.
0 at the falling edge of the signal at the output terminal A of the driver 111A.
(C) shows the driver 1 when the signal at the output terminal B falls.
The data signal HDT [0:63] corresponding to each color is supplied to the driver 111A (Y) at the falling edge of the signal at the output terminal C and to the driver 111A (K) at the falling edge of the signal at the output terminal D. ] Is latched.

In this embodiment, the read address control unit 701 generates the address STRTAD [17: 0] to be supplied to the address counter 702 by generating four PRTRG signals input from the control unit of the drive data generation unit. It shall be updated every time. This means that the resolution of the image data sent from the host computer 200 stored in the image memory 222A is 300 dpi × 300 dpi.
On the other hand, the resolution actually printed is 1200 dpi as shown in FIG. 4, and the magnification is equivalent to four times.

The configuration of the drive data generator 222 has been described above. FIG. 11 conceptually shows the internal operation of the drive data generator 222 and the procedure of data processing.
FIG. 12 is a timing chart of various internal signals referred to in the description of the drive data transfer circuit 222. In FIG. 12, the portion indicated by column 1 is a head driver corresponding to each column of data of two dots each of cyan (C), magenta (M), yellow (Y) and black for one column (column). The column 2 indicates the timing at which the next one column of print data is transferred.

FIG. 11 is a diagram for explaining the procedure of data processing in the drive data generation unit 222 according to the present embodiment.

The CO generated by the read address control unit 701
The LOR signal [1: 0] (“0h” (cyan) in FIG. 11) and the read start address STRTAD signal [17: 0] are combined, and the image memory 222A is output as the IMAGAD signal [19: 0].
(Here, “00000h” at first). Thus, the recording data transferred from the host computer 200 and stored in the image memory 222A, that is, the cyan pixel data CODE signal [3: 0] (“Eh” in FIG. 11) is read. Subsequently, the CODE signal [3: 0] is set to the lower 4 bits, and COLOR
An address signal MAD [5: which uses the signal [1: 0] as the upper 2 bits
0] (001110) is supplied to the address of the memory 703. As a result, the pattern data (8 bits) (the pattern C14 in the figure) corresponding to the recording data ("Eh") is read.

Further, one dot (resolution: 1200 dpi × 600 dpi) constituting the read pattern
Are 8-bit data represented by 1 bit (corresponding to data for 4 columns), and are output from multiplexers 704 and 705.
COLUMN signal [1: 0] (“1” in FIG. 11)
h)), the bit data of the required column is selected from the 8-bit pattern data to be the recording data. In FIG. 11, the print data for the nozzle N0 of the cyan print head is indicated by “0”, and the print data for the nozzle N1 is indicated by “1”.

In the embodiment of the present invention, when each pixel data of the input multi-valued image data is converted into a dot pattern with reference to the memory 703 and recorded, the recording is performed after the recording of one scan is completed. The number of dots is counted, and the duty of the dots in the printing scan is calculated based on the counted number of dots and the total number of dots that can be printed in one main scan. Then, based on the calculated duty, the temperature of the print head is estimated, and in accordance with the estimated temperature, drive data thinning processing is performed and printing is performed by multi-pass.

That is, in the ink jet recording apparatus of the present embodiment, the host computer 200 sends the image memory 2
When the transfer of the image data to the CPU 22A is completed, the CPU 10
No. 0 converts the image data into dot data, and records an image based on the converted dot data. When printing by one scan is completed in this manner, image data of each color printed by the immediately preceding print scan is read out, and a count value reference table (FIG. 13) stored in the ROM 100A or the RAM 100B based on the pixel values (codes). Of 320
With reference to 1), it is determined how many drive data (dots) are included in the dot pattern corresponding to the read pixel data. Such a process is performed on the image data of all the colors subjected to the printing scan, and the total number of dots of each color in the immediately preceding printing scan is obtained. The ratio of the total number of dots of each color and the total value to the total number of dots that can be printed by the print heads of the respective colors CMYK in one main scan, that is, the print duty of each color, is obtained. The temperature of the print head after the end is estimated. When the temperature is estimated to be equal to or higher than the predetermined temperature, the next printing scan is performed by multi-pass.

FIG. 13 is a view for explaining the data configuration of the count value reference table 3201 according to the present embodiment. Note that FIG. 13 shows an example of a dot pattern when the pixel data values are “0h”, “Eh”, and “Fh”. Portions common to FIGS. 5A to 5C have the same numbers. Is shown.

For example, for the patterns C0, M0, Y0, and K0 corresponding to the pixel value "0", there is no drive data to be recorded, as is clear from the dot patterns 501C, 501M, 501Y, and 501K. In the count value reference table 3201, “0” is written at a position corresponding to each pattern. Also,
Patterns C14, M14, Y corresponding to pixel value “Eh”
14 and K14, each of which has six drive data (dots), the count value reference table 3201
"6" is stored in the position corresponding to each of the patterns "." And "8" in the dot pattern corresponding to the pixel value "Fh". “8” is stored in the position corresponding to each pattern.

Therefore, the CPU 100 sets the image data 22
2A, the image data recorded in the immediately preceding recording scan is sequentially read out of the recording data received from the host computer 200, and from the information on the pixel values and colors of the recording data, the recording data recorded in the recording scan is read. In the count value reference table 3201
Can be determined with reference to

FIG. 14 shows the configuration of the CPU 10 according to this embodiment.
It is a flowchart which shows the procedure of data counting and duty calculation by 0. A program for executing this processing is stored in the ROM 100A.

In FIG. 14, first, at step S100
Then, of the image data stored in the image memory 222A, the area of the image data recorded by the immediately preceding recording scan is obtained, and the readout area is designated. Next, step S101
Then, the storage area (RAM 100B) of the count value corresponding to the image data of each color is all initialized to “0”. Then, the process proceeds to step S102, at which image data for one pixel of cyan is read from the area of the image memory 222A, and at step S103, the image data is converted into a dot pattern by referring to the count value reference table 3201 shown in FIG. Then, the number of drive data (dots) when converted to is obtained. Then, the process proceeds to step S104, and the value is added to the cyan counter. Next, proceed to step S105,
For example, in the example of FIG. 8, “20h” is added to the address of the image memory 222A, and the pixel address of the next cyan data in the image memory 222A is obtained.
Proceed to 2. Thus, in step S105, step S1
Steps S102 to S1 until all the pixel data of cyan, magenta, yellow and black in the area designated by 00 is read out and the total number of recorded dots is obtained.
Step 05 is repeated.

When the number of dots recorded in the immediately preceding recording scan corresponding to the pixel data of all the colors in the designated area is obtained in step S105, the process proceeds to step S106, and is obtained in step S104. From the total number of print dots of each color and the total number of dots that can be printed in one print scan, the duty at the time of printing the image data of each color was obtained, and based on this duty, printing was performed in the immediately preceding print scan. Estimate the temperature rise of the recording head.

Then, the process proceeds to a step S107 to check whether or not the estimated temperature of the recording head is equal to or higher than a predetermined temperature. If so, the process proceeds to step S108, and the next printing scan is
Set the recording mode to record by pass. on the other hand,
If it is estimated that the temperature is equal to or lower than the predetermined temperature, the process proceeds to step S109, and the print mode is set so that the next print scan is performed in one pass.

Such processing is performed after the end of each print scan, and if it is determined that the estimated temperature of the print head based on the number of dots printed by the immediately preceding print scan is equal to or higher than the predetermined temperature, the next print scan is performed. Recording by multi-pass is performed. Thereby, the temperature rise of the recording head can be suppressed within a predetermined range.

As described above, according to the present embodiment, it is possible to record an image with less influence of the self-heating of the recording head, so that a high-quality image can always be recorded.

In the above example, at least one of
When the temperature of the color print head is considered to be higher than the predetermined temperature, multi-pass printing is performed in the next print scan. For example, if the temperature of at least two color print heads becomes higher than the predetermined temperature. If so, multi-pass printing may be performed in the next printing scan.

In this embodiment, when the above-described multi-pass (two-pass) printing is performed, the pattern stored in the memory 703 for the pseudo halftone processing and the resolution conversion processing is changed for each scan (pass). Is done. That is, in the present embodiment, the mask pattern for thinning out the drive data is changed between the first pass and the second pass, and a dot pattern corresponding to one pixel data is printed in two scans. I have.

In this embodiment, the printing head temperature at the end of printing is calculated by calculating the duty based on the counted number of dots and the total number of printable dots in one scan (pass). The temperature of the recording head is estimated based on the calculated duty. Here, the correspondence between the duty and the temperature rise of the recording head is determined in advance based on calculations or experiments, and it is assumed that a table for estimating the temperature is stored in, for example, the ROM 100A.

In the present embodiment, the data counting means for counting the number of dots recorded immediately before the end of printing, the total number of dots printable by one main scan and the number of dots counted by the data counting means. Duty calculating means for calculating the duty based on the number, temperature estimating means for estimating the temperature of the recording means at that time based on the duty calculated by the duty calculating means, and recording means estimating the temperature estimating means Although the CPU 100 executes various functions such as a judging means for judging whether or not the temperature is equal to or higher than a predetermined value, a separate hardware means may be provided and executed if the processing speed is to be improved.

Further, in this embodiment, the image data for each color is transferred from the host computer. However, for example, a configuration in which drive data for a plurality of colors is generated from image data for one color may be used.

Further, in the present embodiment, Japanese Patent Application No. 5-89
A configuration may be used in combination with a PWM driving method as disclosed in JP-A-791. In such a case, a predetermined value may be set so that switching to multi-pass printing is performed when it is determined that the temperature of each print head after printing ends deviates from the temperature range in which the ejection amount can be corrected by PWM driving. .

Hereinafter, each embodiment in the case where such multi-pass printing is performed will be described.

[Embodiment 1] FIG. 15 is a diagram showing an example of this mask pattern. Here, a zigzag or inverted zigzag mask pattern is shown.

In FIG. 15, reference numeral 1301 denotes 300 dpi × 300 d input from the host computer 200.
It indicates the size of a pixel corresponding to pi, and this pixel data is represented by multi-valued 4 bits. 1302, as described above, converts 300 dpi multi-valued pixel data to 1200 dpi ×
A pattern represented by 8 dots of 600 dpi is shown.
302A denotes a mask pattern used in the first pass;
302B indicates a mask pattern used in the second pass.

In the pattern 1302A used in the first pass, 1312A, 1313A, 1316A, 1317A
The dot data corresponding to the positions indicated by. Are recorded without being thinned out.
The dot data corresponding to the positions indicated by 5A and 1318A are thinned out and forcibly become “0” data. Also,
In the pattern 1302B used in the second pass, 1311
The dot data corresponding to the positions indicated by B, 1314B, 1315B and 1318B are recorded without being thinned out, but are recorded at 1312B, 1313B, 1316B and 131.
The dot data corresponding to the position indicated by 7B is thinned out and forcibly becomes “0” data.

In the first embodiment, CPU 100
Before starting printing of the pass, a pattern obtained by ANDing the thinning pattern 1302A shown in FIG. 15 with the pattern for the pseudo halftone processing and the resolution conversion processing shown in FIG. 4B or FIG. Ask for. Next, before starting the printing of the second pass, the logical product of the thinning pattern 1302B shown in FIG. 15 and the patterns for the pseudo halftone processing and the resolution conversion processing shown in FIG. 4B or FIG. The obtained patterns are obtained, and each is written to the memory 703.

FIG. 16 is a diagram showing an example of the development of pattern data when the multi-valued pixel value of the recording data of each color of CMYK is "Eh". The parts common to FIG. They have the same numbers.

The pattern C14A, the pattern M14A, the pattern Y14A, and the pattern K14A are each a pattern 515C to 515K corresponding to the pixel data (Eh) and a thinning pattern 1302 of each color shown in FIG.
A pattern of the first pass corresponding to each color, which indicates a result of a logical product with A, a pattern C14B, a pattern M14
B, pattern Y14B and pattern K14B are patterns 515C to 515K corresponding to pixel data (Eh).
And a thinning pattern 1302B shown in FIG.
And the second pass pattern corresponding to each color, which shows the result of the logical product of

FIGS. 17A and 17B are diagrams for explaining how the calculation results of the logical product shown in FIG. 16 are stored in the memory 703, respectively.

FIG. 17A shows a state in which the result of the logical product of the pattern data and the thinning pattern 1302A (drive data of the first pass) is stored in the memory 703.
7B shows the pattern data and the thinned-out pattern 1302B
And the result of the logical product (drive data of the second pass) is stored in the memory 7
03 shows the state stored.

FIGS. 18 and 19 are views for explaining an example of the recording result in the first embodiment. FIG.
FIG. 19 shows print data for the first pass and second pass for cyan C data, and FIG. 19 shows a print result for cyan C data.

FIG. 20 is a timing chart of an internal signal in the drive data generation unit 222 at the time of printing in the first pass, and FIG. 21 is a timing chart of an internal signal in the drive data generation unit 222 at the time of printing in the second pass. Is shown.

As is apparent from a comparison between these timing charts and the timing chart of FIG. 12, for example, as shown by 1701 in FIG. 20 and 1801 in FIG. 21, the first pass is performed for the same cyan data (Eh). The other operation timings are the same as those in FIG. 12 except that different patterns are read out in the second pass and the second pass, respectively.

FIG. 22 shows CPU 200 according to the first embodiment.
Is a flowchart showing recording control for one band in a multi-pass according to the first embodiment, and a control program for executing this processing is stored in the ROM 100A.

This processing is performed in step S10 of FIG.
In the case where the multi-pass print mode is set in step 8, the process starts when image data for the next print scan starts to be received. Although FIG. 22 shows a case where image data is received from the host computer 200, the process may be started in a state where the image data is already stored in the image memory 222A. To S2 can be omitted.

First, in step S1, it is checked whether image data has been received from the host computer 200. If image data has been received, the flow advances to step S2 to store the received image data in the image memory 222A. In step S3, a predetermined amount of image data is stored in the image memory 222A or the host computer 200
When the start of the printing operation is instructed by inputting a printing start instruction from the printer or the like, the process proceeds to step S4, and the read address control unit 701 reads out the print data of each color for the next print scan from the image memory 222A. Set the address. Next, in step S5, the pattern data (see FIG. 9) stored in the image memory 703 is multiplied by, for example, mask data “01100110” in the example of FIG. 15, and the result is stored in the same address of the memory 703. Store. As a result, the above-described pattern data (drive data) for one pass is stored in the memory 703.

Thus, the process proceeds to step S6, in which the rotation drive of the carriage motor 20 is started, and the PRTRG signal is output to the read address control unit 701. As a result, the drive data generation unit 222 shown in FIG.
Image memory 22 received from host computer 200
2A, reading out the recording data (code) stored in
The data is developed into drive data according to the pattern data stored in the memory 703 and output to the head driver 111A. In this manner, each print head is driven in synchronization with the scan of the print head corresponding to each color (S7), and at step S8, 1 is set.
It is checked whether the recording for the pass has been completed, and if not completed, the processing of steps S7 and S8 is repeated.

When printing of one pass is completed in this way, the process proceeds to step S9, where the carriage 2 is returned to the home position. Then, the process proceeds to step S10, where the pattern data stored in the image memory 703 (see FIG. In the example of FIG. 15, the mask data of “10011001” for the second pass is multiplied, and the result is stored in the same address of the memory 703. Then, the process proceeds to step S11, and the second pass printing is performed in steps S11 to S12 in the same manner as in steps S6 to S8 described above. When the printing of the second pass is completed, the process proceeds to step S14, in which the carriage 2 is returned to the home position, the paper feed motor 50 is driven to rotate, and the print paper is conveyed by the print width to be printed in one scan. The printing process for one scan is completed.

Thus, the recording result as shown in FIG. 19 is obtained by the two scans.

In FIG. 18, for simplification of the explanation, the case where the recording paper is not conveyed in the sub-scanning direction between the first pass and the second pass is described. However, the present invention is not limited to this.

[Second Embodiment] In the first embodiment, the CPU is used for each scan (pass) of the print head.
100 is a memory 703 for logical product calculation and the calculation result
Was writing to. On the other hand, Embodiment 2
Now, a memory 1901 having twice the memory capacity is provided,
A case will be described in which pattern data for two passes is stored in the memory 1901, and printing is performed at high speed only by changing the read address of the memory 1901 for each pass.

The structure of the ink jet recording apparatus according to the second embodiment is substantially the same as that of FIG. 2 described above. However, in the second embodiment, the drive data generator has the structure as shown in FIG. Therefore, the difference from the configuration of the first embodiment is that a signal line for transmitting the SCAN signal to the drive data generation unit 223 is added.

FIG. 23 is a diagram showing the internal configuration of the drive data generation unit 223 according to the second embodiment. Portions in common with the configuration of FIG. 7 shown in the first embodiment have the same reference numerals. The description is omitted.

As is apparent from a comparison between FIG. 7 and FIG. 23, in the second embodiment, a memory 1901 for performing pseudo-halftone processing and resolution conversion processing by referring to a table in real time is provided. The storage capacity is twice as large as that of the first embodiment. The most significant bit of the address input of the memory 1901 includes the CPU 1
A SCAN signal controlled by 00 is provided.

In the second embodiment, the staggered / inverted staggered pattern shown in FIG. 15 is used as in the first embodiment. In the first embodiment, such pattern data is calculated for each scan (pass). In the second embodiment, the thinning patterns 1302A and 1302B, the pseudo halftone process, and the resolution conversion process are performed. AND calculation with the pattern for
100, and the calculation results are all stored in the memory 1901.

FIG. 24 is a diagram showing how the calculation results of the logical product are stored in the memory 1901 in the second embodiment.

The addresses "00h" to "0Fh" of the memory 1901 correspond to the patterns C0A to C15.
A, that is, a storage area for pattern data for the first pass cyan C, and a storage area for pattern data for magenta M for the first pass from addresses “10h” to “1Fh”;
Addresses “20h” to “2Fh” are storage areas for pattern data for yellow Y in the first pass, and addresses “30h” to “3Fh” are storage areas for pattern data for black K in the first pass. . Further, the upper addresses "40h" to "4Fh" correspond to the pattern C0B.
To pattern C15B, that is, pattern data for cyan C in the second pass, pattern data for magenta M in the second pass from addresses "50h" to "5Fh", and pattern data for magenta M in the second pass, and two paths for addresses "60h" to "6Fh" The storage area for the pattern data for the yellow Y of the eye and the addresses “70h” to “7Fh” is the pattern data for the black K of the second pass.

As described above, the switching of the pattern data of the first pass and the second pass is performed by the most significant bit ADRS6 (MAD6) of the address input of the memory 1901, that is, the CPU.
100 supplied to the drive data generation unit 223 from the SCA 100
It is controlled by whether the N signal is “1” or “0”. Therefore, the CPU 100 sets the value of the SCAN signal to “0” before the start of the first pass printing, and sets the value of the SCAN signal to “1” before the start of the second pass printing.
In the first pass, printing using the pattern data of the first pass is performed for each color, and in the second pass, printing using the pattern data of the second pass is performed.

This corresponds to, for example, the step S in the flowchart of FIG.
This can be easily realized by setting the SCAN signal to "0" in step S5 and setting the SCAN signal to "1" in step S10 for performing two-pass print scanning.

As is clear from the above description, in the second embodiment, it is not necessary to perform the logical product calculation and the writing to the memory for each scan (pass), and it is possible to perform recording at a higher speed. .

As described above, according to the second embodiment, when it is determined that the temperature of at least one of the CMYK color print heads is equal to or higher than the predetermined value, the next print scan is performed. Is switched to multi-pass printing, the duty in the next scan (pass) is reduced, and the effect of self-heating of the print head due to ink ejection is reduced. Also, logical product calculation and memory 703
Since it is not necessary to perform writing to the memory for each scan (pass), it is possible to prevent a decrease in throughput due to logical product calculation and writing to the memory 703.

[Embodiment 3] In Embodiments 1 and 2 described above, thinning is performed using a specific mask pattern such as a staggered or inverted staggered pattern. Depending on the pattern for the resolution conversion processing and the recording data, the data signal HDT for driving the nozzles and the mask pattern have the same period, and the recorded dot array forms a moiré pattern having a specific direction. A phenomenon called "."

Therefore, in the third embodiment, a plurality of thinning patterns are prepared, and each pattern is selectively used within one scan (pass) to prevent moire from occurring, and to prevent image quality degradation due to density unevenness. We propose a multi-pass printing method that reduces effectively.

The configuration of the control block of the ink jet recording apparatus according to the third embodiment is substantially the same as the configuration of FIG. 2 described above, but the configuration of the drive data generation unit 224 is the same as that of FIG.
And the SCAN signal line is supplied from the CPU 100 to the drive data generation unit, which is different from the configuration of the first embodiment.

FIG. 25 is a diagram for explaining another mask pattern example different from the mask pattern of the first embodiment and a recording example thereof.

In FIG. 25, similar to the case of FIG. 15, reference numeral 2101 denotes one pixel data (code) of the recording data received from the host computer 200;
Reference numeral 2 denotes a dot array when the pixel is subjected to pseudo halftone processing and recorded.

Thinning pattern 210 used in the first pass
In 2C, 2112C, 2113C, 2115C, 21
The recording data corresponding to the dot position of 18C is recorded without thinning, and 2111C, 2114C, 2116C,
The print data corresponding to the position 117C is thinned out to forcibly become “0” data. In the thinning pattern 2102D used in the second pass, 2111D, 2114D,
2112D, 2113D, and 2115D without thinning out print data corresponding to the positions of 2116D and 2117D.
D, the recording data corresponding to the position of 2118D is thinned out to forcibly become "0" data.

The logical product of these thinning patterns and the patterns for the pseudo halftone processing and the resolution conversion processing corresponding to the cyan data “Eh” shown in FIG. 4B or 5B is calculated. FIG. 26 shows an example of the result of the above.

FIG. 27 is a block diagram showing the internal configuration of the drive data generation unit 224 of the third embodiment. Components having the same functions as those of the components shown in the first and second embodiments are denoted by the same reference numerals. And description thereof is omitted.

As is apparent from FIG. 27, in the third embodiment, the memory capacity of the memory 2301 for performing the pseudo halftone processing and the resolution conversion processing by referring to the table in real time is the same as that of the first embodiment. The storage capacity is four times that of the case.

In FIG. 27, the SCAN signal controlled by the CPU 100 is stored in the sixth bit (MAD6) of the address input of the memory 2301, and the 1-bit counter 230 is stored in the most significant bit (7th bit: MAD7) of the address.
The PIXEL signal, which is the output signal of No. 3, is supplied.

The 1-bit counter 2303 receives, at its clock input, a signal COLUMN, which is output from the 2-bit counter 707 and indicates the column position to be printed, decoded and input. That is, the signal PRTR supplied from the CPU 100 every (1/1200) dpi
The result of counting G is input to an OR gate 2302, where a decoded signal is supplied. The output of the gate 2302 becomes “0” when the count value (COLUMN [1: 0] signal) of the 2-bit counter 707 is “0h”. Therefore, this 2-bit counter 707
Every time the count value becomes “0h”, that is, every four columns, the 1-bit counter 2301 counts.

FIG. 28 is a diagram showing data contents of memory 2301 in the third embodiment.

As is clear from the figure, the pattern for thinning out the zigzag and inverted zigzag patterns used in the second embodiment is provided at addresses “00h” to “7Fh” of the memory 2401 (based on FIG. 15). Is stored. That is, in the addresses “00h” to “3Fh” of the memory 2401, the cyan pattern data C0A to C1 for one pass are stored.
5A, magenta pattern data M0A to M15A,
Pattern data Y0A to Y15A for yellow and pattern data K0A to K15A for black are stored. In addition, from address “40h” of memory 2401 to “7F
h ”is the pattern data C0B for cyan for two passes.
To C15B, pattern data M0B to M1 for magenta
5B, pattern data Y0B to Y15B for yellow,
Pattern data K0B to K15B for black are stored.

Further, the address “80” of the memory 2301
From “h” to “BFh”, pattern data C0C to C15C for cyan for one pass, pattern data M0C to M15C for magenta, and yellow Pattern data Y0C to Y15C, and pattern data K0C for black
To K15C are stored in the address “C
From “0h” to “FFh”, the two-pass cyan pattern data C0D to C15D, the magenta pattern data M0D to M15D, and the yellow pattern data Y0
B to Y15D, black pattern data K0B to K15D
Is stored.

That is, after the scanning of one line is started,
Since the PIXEL signal is “0” in the first to fourth columns, the address “00h” of the memory 2301 shown in FIG.
The pattern data of addresses “80h” to “FFh” of the memory 2301 shown in FIG. 28 is read because the PIXEL signal is “1” in the next four columns. Will be recorded.

Of course, similarly, in the second pass printing, the pattern data C0B to C15B for cyan, the pattern data M0B to M15B for magenta, and the pattern data Y for yellow are printed in the first to fourth columns.
0B to Y15B, pattern data K0B to K15 for black
B is read from the memory 2301 and recorded, and the PIXEL signal is "1" from the fifth column to the eighth column, and the cyan pattern data C0D to C15D, the magenta pattern data M0D to M15D, and the yellow pattern It goes without saying that the data Y0D to Y15D and the pattern data K0D to K15D for black are recorded.

Further, during the recording of the first pass, the CPU 10
The fact that 0 sets the value of the SCAN signal to "0" and "1" at the time of recording in the second pass is the same as in the above-described embodiment.

FIG. 29 is a diagram showing an example of a timing chart of an internal signal of the drive data generating section 224 at the time of the first pass recording according to the third embodiment of the present invention, and FIG. FIG. 9 is a diagram illustrating an example of print data of an eye and a second pass.

In FIG. 29, as shown by 2501,
A pattern C14A based on the mask pattern in FIG. 15 is generated for the cyan data having the pixel value “Eh” in the first column, while the cyan data having the pixel value “Eh” in the fifth column 2502 shown in FIG. It can be seen that a pattern C14C based on the mask pattern of FIG.

FIG. 30 is a diagram showing an example of cyan print data in the first pass and cyan print data in the second pass in the third embodiment.

As is clear from FIG. 30, the first pass and the second pass
In each of the passes, in columns 1 to 4, FIG.
It can be seen that recording is performed with a pattern based on the mask pattern of No. 5, and that the columns 5 to 8 are recorded with a pattern masked based on the mask data of FIG. Thus, the mask data to be masked is changed every four columns, and printing is performed.

As is apparent from the above description, according to the third embodiment, two thinning patterns are used alternately every four columns, so that the data signals HDT [0:63] for driving the nozzles are used. Thus, it is possible to suppress the occurrence of moire caused by the mask pattern having the same period, and thereby to realize a multi-pass printing method in which deterioration of image quality due to density unevenness is effectively reduced.

[Fourth Embodiment] FIG. 31 is a block diagram showing an internal configuration of drive data generating section 222 according to a fourth embodiment of the present invention, and has the same functions as the components shown in the above-described embodiment. Are denoted by the same reference numerals, and their description is omitted.

In the fourth embodiment, 21-bit counters 3401 to 3408 are provided for counting the number of dots recorded in one recording scan.

In FIG. 31, counters 3401, 34
02 is a counter for counting the number of dots of cyan driving data, counters 3403 and 3404 are counters and counters for counting magenta driving data.
Reference numerals 05 and 3406 denote counters for counting the number of dots of yellow drive data, and counters 3407 and 3408 denote counters for counting the number of dots of drive data for black. A CLK signal for address increment for the address counter 702 is input to the clock signal of each of these counters, and an output signal of the multiplexers 704 and 705 is provided to a control input ENB for controlling the counting of the counters 3401 to 3408. SDO, SDE,
2-bit signal COLO indicating the color of the drive data to be processed
Each signal obtained by decoding R [1: 0] with a 2-bit decoder 710 is supplied via AND gates 3411 to 418.

The number of bits that can be counted by these counters is set to a value equal to or larger than the total number of dots that can be printed in one scan (pass).

For example, in the case of cyan data,
The number of dots in the upper line recorded in the 2 × 4 dot pattern is counted by the counter 3401, and the number of dots in the lower line is counted by the counter 3402. CPU 100 for controlling the inkjet recording apparatus
Can read the count value of each of these counters 3401 to 3408, and can read these counters 3401 to 344 at an arbitrary timing such as at the start of each printing scan.
It is assumed that the value of 08 can be reset to “0”.

That is, the CPU 100 reads out the count values of the counters 3401 to 3408 every time printing by each printing scan is completed, and shows the count value 3401 indicating the count value for the same color.
And 3402 (cyan), 3403 and 3404 (magenta), 3405 and 3406 (yellow), 3407 and 3408 (black), and a counter 3401. ~ 3
The count value of 408 is initialized. Subsequently, the print duty of each print head is calculated based on the count value for each color of CMYK and the total number of dots that can be printed by each print head, and the temperature at the end of printing in each print head of CMYK is calculated. Is estimated. As a result of this temperature estimation,
If it is determined that at least one temperature of each of the CMYK print heads is equal to or higher than a predetermined value, the print scan is switched from the next print scan to a multi-pass print scan. Since the operation of this multi-pass printing is the same as that of the above-described embodiment, the description is omitted here.

According to the third embodiment, the multi-valued image data is input, the pseudo halftone process and the resolution conversion process are performed on the multi-valued image data, and the multi-valued image data is recorded. Therefore, the processing speed can be further increased as compared with the case where the CPU 100 performs counting using software as in the above-described embodiment.

Further, according to the third embodiment, it is possible to immediately delete the recorded image data stored in the image memory 222A, so that the memory use efficiency of the image memory 222A can be improved. It also has the effect of being

In the drive data generation unit shown in FIGS. 7, 17 and 23 corresponding to the above-described embodiment, similarly to the third embodiment, a counter for counting the output signals of multiplexers 704 and 705 is used. 3401 to 3408
May be provided.

In each of the above-described embodiments, the drive data for each of CMYK colors is individually set on the assumption that the self-heating caused by the ink ejection from one print head hardly affects the temperature of another print head. Counting,
The temperature of each of the print heads of CMYK was estimated. However, when it is possible to predict in advance that the temperature rise of one recording head greatly affects the temperature of another recording head, such as when the recording heads of the respective colors are very close to each other,
Regardless of the number of drive data of each color, the number of drive data of all colors (the number of all dots) is counted. Then, the average temperature of all the print heads may be estimated based on the count value, and if the estimated average temperature is equal to or higher than a predetermined temperature, switching to multi-pass printing may be performed.

Also, based on the generally widely known fact that the density unevenness of the Y ink is hardly noticeable to human eyes,
As a result of estimating the temperature of each print head, for example, when it is estimated that only the temperature of the Y print head is equal to or higher than the predetermined temperature and the other print heads are assumed to be lower than the predetermined temperature, multi-pass printing is started. May not be performed.

On the other hand, when it is estimated that the temperature of at least one of the other recording heads except the Y recording head, ie, the C, M, and K recording heads, is higher than a predetermined temperature, Switching to multi-pass printing may be performed. Alternatively, without estimating the temperature of the Y print head,
The temperature of the print head may not be used as a material for determining whether or not to perform multi-pass printing.

Further, in this embodiment, an example of an ink jet recording apparatus has been described. However, the present invention is not limited to this, and may be applied to various printers such as a thermal printer, a thermal transfer printer, and a wire dot printer. It is possible.

Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), a device including one device (for example, a copying machine, a facsimile machine) Etc.).

An object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU or MPU) of the system or the apparatus. Is also achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) Performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The case where the CPU of the function expansion board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing is also included.

As described above, according to the present embodiment, the fluctuation of the ink ejection amount can be achieved without increasing the cost for a printing apparatus that performs the pseudo halftone processing and the resolution conversion processing by referring to the table in real time. Therefore, it is possible to provide a printing apparatus capable of performing multi-pass printing in which the deterioration of image quality due to image quality is effectively reduced.

[0148]

As described above, according to the present invention, pseudo halftone processing and resolution conversion processing are performed on multi-valued image data in real time, and the temperature rise of the recording head is suppressed, and ink ejection is performed. There is an effect that the deterioration of the image quality due to the fluctuation of the amount can be effectively reduced.

Also, according to the present invention, the 1
The current print head temperature is estimated based on the number of dots in the print scan, and based on the estimated temperature, whether the next print scan is performed by a plurality of print scans or by one print scan is performed. The determination has an effect that a high-quality image can be recorded while suppressing a rise in the temperature of the recording head.

[0150]

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an outline of a recording unit of an ink jet recording apparatus according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a main part of the inkjet recording apparatus according to the embodiment.

FIG. 3 is a diagram schematically illustrating a recording head used in the ink jet recording apparatus according to the embodiment.

4A and 4B are diagrams for explaining conversion from data transferred from a host computer to data for driving each nozzle of a print head. FIG. 4A illustrates pixel data of 300 dpi and dots for actual printing. FIG. 7B is a diagram illustrating a relationship between the pixel data “8h” and the corresponding pattern data.

FIG. 5 is a diagram for explaining a relationship between print data of each color sent from a host computer and data (pattern data) for driving each nozzle of a print head corresponding to each color.

FIG. 6 is a diagram illustrating a relationship between received data and a printing result in the inkjet printing apparatus of the present embodiment.

FIG. 7 is a block diagram illustrating a configuration of a drive data generation unit in the inkjet recording apparatus according to the present embodiment.

FIG. 8 is a diagram illustrating an example of storage in an image memory in the inkjet recording apparatus according to the present embodiment.

FIG. 9 is a diagram showing a state in which pattern data used to convert print data received from a host computer into print head drive data is stored in a memory.

FIG. 10 is a diagram showing storage contents of a memory in a drive data generation unit in the ink jet recording apparatus of the present embodiment.

FIG. 11 is a diagram conceptually illustrating a processing procedure in a drive data generation unit in the inkjet recording apparatus according to the present embodiment.

FIG. 12 is a timing chart illustrating an operation of a drive data generation unit in the inkjet recording apparatus according to the present embodiment.

FIG. 13 is a diagram illustrating a count value reference table referred to by a CPU according to the present embodiment.

FIG. 14 is a flowchart illustrating a procedure in which the CPU determines whether to perform multi-pass printing or one-pass printing in the present embodiment.

FIG. 15 is a diagram illustrating a thinning pattern for thinning a table reference pattern used in the first embodiment.

FIG. 16 is a diagram illustrating a thinned-out table reference pattern stored in the memory of the drive data generation unit in the first embodiment.

FIG. 17 is a diagram illustrating the storage contents of each path in the memory of the drive data generation unit according to the first embodiment.

FIG. 18 is a diagram illustrating an example of a print result of a first pass and a second pass in the inkjet printing apparatus according to the first embodiment.

FIG. 19 is a diagram illustrating an example of a printing result in two passes in the inkjet printing apparatus according to the first embodiment.

FIG. 20 is a timing chart showing an operation of the drive data generation unit in the first pass printing in the ink jet printing apparatus according to the first embodiment.

FIG. 21 is a timing chart illustrating a second-pass printing operation performed by the drive data generation unit according to the first embodiment.

FIG. 22 is a flowchart illustrating control processing by the CPU of the inkjet recording apparatus according to the first embodiment.

FIG. 23 is a block diagram illustrating a configuration of a drive data generation unit of the inkjet recording apparatus according to the second embodiment of the present invention.

FIG. 24 is a diagram illustrating data contents stored in a memory of a drive data generation unit according to the second embodiment.

FIG. 25 is a diagram showing a thinning pattern for thinning a table reference pattern used in the third embodiment.

FIG. 26 is a diagram showing a table reference pattern stored in the memory of the drive data generation unit and subjected to different thinning-out in the third embodiment.

FIG. 27 is a block diagram illustrating a configuration of a drive data generation unit according to the third embodiment.

FIG. 28 is a diagram illustrating data contents stored in a memory of a drive data generation unit according to the third embodiment.

FIG. 29 is a timing chart showing a printing operation in the first pass by the drive data generation unit according to the third embodiment.

FIG. 30 is a diagram illustrating an example of a recording result according to the third embodiment.

FIG. 31 is a block diagram illustrating a configuration of a drive data generation unit according to the third embodiment.

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Claims (16)

[Claims] 1. A printing apparatus for printing by moving a printing head having a plurality of printing elements relative to a printing medium, comprising: holding means for holding input multi-valued image data; A memory for converting the output multi-valued image data into dot data, and inputting the multi-valued image data to an address of the memory, and converting the multi-valued image data based on data read from the memory. Conversion means for converting to dot data; counting means for counting the number of dots printed by printing scan by relative movement of the printing head; and temperature of the printing head based on the count value counted by the counting means. A temperature estimating means for estimating, and a printing control means for printing an image by one printing scan or a plurality of printing scans according to the temperature estimated by the temperature estimating means. Conversion control means for changing the dot data between a first print scan and a second print scan of the print head during printing by the plurality of print scans; and And a drive control unit that outputs the dot data corresponding to the plurality of print elements of the print head and drives the drive. 2. The method according to claim 1, wherein the conversion control means converts the dot data recorded in each of the first recording scan and the second recording scan of the recording head so as to have a complementary relationship with each other. The recording device according to claim 1. 3. The printing control apparatus according to claim 1, wherein the printing control unit is configured to perform a first print scan of the print head and a second print scan during printing by a plurality of print scans.
3. The printing apparatus according to claim 1, wherein the content of the memory is changed before the second printing scan. 4. The printing apparatus according to claim 1, wherein the memory stores dot data corresponding to a first print scan and a second print scan of the print head with respect to the multi-valued image data, and the conversion control unit performs the first print scan. 3. The printing apparatus according to claim 1, wherein a read address of the memory by the conversion unit is changed between a scan and a second print scan. 5. The memory stores at least two types of dot data different from each other for a first print scan and a second print scan of the print head with respect to the multi-valued image data. 3. The printing apparatus according to claim 1, wherein the control unit changes a read address of the memory by the conversion unit according to a number of times of the print scan and a print position of the print head. 4. 6. The apparatus according to claim 1, wherein the dot data is data for converting at least one of a resolution and a gradation number of the multi-valued image data.
The recording device according to claim 1. 7. The recording apparatus according to claim 1, wherein the multi-value image data includes multi-value image data of a plurality of colors. 8. The memory stores dot data corresponding to each of a plurality of colors, and at least the multi-valued image data and color information indicating the color of the multi-valued image data are input as addresses of the memory. The recording apparatus according to claim 7, wherein the recording is performed. 9. A recording method in a recording apparatus for recording by moving a recording head having a plurality of recording elements relative to a recording medium, wherein the memory converts input multi-valued image data into dot data. A conversion step of inputting the multi-valued image data to the address and converting the multi-valued image data into dot data based on the data read from the memory; and recording by the recording scan by relative movement of the recording head. A counting step of counting the number of dots; a temperature estimating step of estimating the temperature of the print head based on the count value counted in the counting step; and one printing scan in accordance with the estimation result in the temperature estimating step. Or a printing control step of printing an image by a plurality of printing scans, and printing the dot data by the printing head during printing by the plurality of printing scans. A conversion control step of changing between a first print scan and a second print scan, and a drive control for outputting and driving the dot data converted in the conversion control step in accordance with a plurality of print elements of the print head. And a recording method. 10. In the conversion control step, when printing is performed by a plurality of printing scans, the contents of the memory are changed before the first printing scan and the second printing scan of the printing head. The recording method according to claim 9. 11. The memory according to claim 1, wherein the memory stores dot data corresponding to a first print scan and a second print scan of the print head with respect to the multi-valued image data. 10. The printing method according to claim 9, wherein a read address of the memory in the conversion step is changed between a scan and a second print scan. 12. The memory according to claim 1, wherein the memory stores at least two types of dot data different from each other for a first print scan and a second print scan of the print head with respect to the multi-valued image data. 10. The printing method according to claim 9, wherein in the control step, a read address of the memory in the conversion step is changed according to a number of times of the print scan and a print position by the print head. 13. The apparatus according to claim 9, wherein the dot data is data for converting at least one of a resolution and a gradation number of the multi-valued image data. The recording method described. 14. The multi-valued image data includes multi-valued multi-valued image data, and each of the multi-colored multi-valued image data is multi-valued multi-valued image data. The recording method according to any one of the above items. 15. The memory stores dot data corresponding to each of a plurality of colors, and at least the multi-valued image data and color information indicating the color of the multi-valued image data are input as addresses of the memory. The recording method according to claim 14, wherein recording is performed. 16. In the conversion control step, the dot data recorded in each of the first print scan and the second print scan of the print head are converted so as to have a complementary relationship with each other. The recording method according to claim 9.