JP2003080682A - Image processing apparatus, image processing method, recording apparatus, recording method program, storing medium for storing program code readable by computer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus in which granular feeling of dots can be decreased over the whole density region by setting amounts of forming low density dots and high density dots per unit area at an optimum, an image processing method, a recording apparatus, a recording method, a control program for controlling the recording apparatus and a storing medium for storing the program. SOLUTION: As the density level is increased, the amount of forming of the low density dots is gradually increased to the first maximum amount (200%) and then, it is gradually decreased and in a range (B) of the higher density level than a specified density level being at most the density level corresponding to the first maximum amount (200%), as the density level is increased, the amount of forming of the high density dots is gradually increased to the second maximum amount (100%) being smaller than the first maximum amount to determine the amounts of forming of the low density dots and the high density dots corresponding to the density level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and an image processing method for determining the formation amount of high density dots and low density dots on a recording medium according to the density level of input image data. The present invention relates to a recording device and a recording method using them, a program, and a storage medium storing a computer-readable program code.

[0002]

2. Description of the Related Art As a conventional ink jet recording apparatus, for example, three color inks of cyan (C), magenta (M) and yellow (Y) or four color inks of cyan, magenta, yellow and black (K) are used. There is one in which dots are formed by using ink and ejecting those inks onto a recording medium. In such a recording apparatus, dots may be conspicuous in the highlight portion (low-density area) of the image, resulting in an increased graininess.
As a method to reduce the graininess of such dots,
With respect to inks having low lightness such as cyan and magenta, there is a method of using a light ink having a low density of about ⅓ to ⅙ of the normal ink density. There are the following three recording methods using light ink. (1) Light ink is applied to the highlight portion, and light ink is applied to the shadow (high density area) in an overlapping manner. (2) Light ink is applied to the highlight area and dark ink is applied to the shadow area. (3) Light ink is applied to the highlight area, medium density ink is applied to the middle density area, and dark ink is applied to the shadow area.

[0003]

In the case of the recording method of the above (1), since the density of the shadow portion is increased by repeatedly striking the light ink, the consumption of the light ink becomes larger than usual, Running costs are high. Further, in order to secure the density, particularly when recording a secondary color or a tertiary color, the ink overflows due to an increase in the amount of ejected ink, and the image quality deteriorates. Also,
The usable recording medium is limited due to the relationship with the maximum ink ejection amount.

In the case of the recording method of the above (2), by selectively using the ink to be ejected in the highlight portion and the shadow portion, it is possible to reduce the graininess in the highlight portion, increase the density in the shadow portion and reduce the ink consumption amount. I am trying to achieve both. However, if the density of the light ink is made as thin as possible, the graininess of the highlight part will be reduced,
Since the density difference between the light ink and the dark ink becomes large, the dots become conspicuously large in the medium density area where the dark ink dots start to enter the light ink dot formation area. Further, when the density of the light ink is increased in order to reduce the graininess of the dots in the medium density area, the dots of the light ink are visible, and the dots in the highlight area are noticeably increased in graininess. I will end up.

In the case of the recording method of the above (3), by using the medium density ink, the granularity of dots in the medium density area is reduced, but for one hue, the dark ink, the medium density ink, Further, it is necessary to provide three types of recording heads for ejecting light ink and three types of ink, which causes a cost increase. Further, when performing image processing, it is necessary to have three color tables for one hue, which makes the image processing complicated.

Further, as a recording method which does not use light ink, in order to achieve the same image quality as that of (1), (2) and (3) using light ink, for example, ink droplets forming dots. Is a small droplet of about 0.5 pl (picoliter), and a dot smaller than usual is formed to reduce the graininess of the highlight portion. However, with this recording method, the recording resolution increases and the recording speed slows down,
Since it is difficult to stably land the ink droplets on the target landing position, and it is difficult to manufacture the recording head,
There is a possibility that cost may increase due to deterioration of the yield of the recording head.

An object of the present invention is to provide an image processing apparatus and image processing capable of reducing the granularity of dots over the entire density region by optimally setting the formation amounts of low density dots and high density dots. A method, a recording apparatus, a recording method, a control program for controlling the recording apparatus, and a storage medium storing the program.

[0008]

In order to achieve the above object, the present invention provides a low density per unit area of a recording medium according to a density level of input image data for recording an image on the recording medium. An image processing apparatus comprising a determination unit that determines the formation amount of dots and high-density dots, wherein the determination unit increases the formation amount of the low-density dots to a first maximum amount as the density level increases. In the range of the density level that is gradually increased and then gradually decreased, and is higher than a predetermined density level when the predetermined amount of the low-density dots is formed, the higher the density becomes, the higher the density becomes. Of the low-density dots and the high-density dots corresponding to the density levels by gradually increasing the formation amount of the dots to the second maximum amount that is smaller than the first maximum amount. Determination characterized in that it.

Further, according to the present invention, the formation amount of low-density dots and high-density dots per unit area of the recording medium is determined according to the density level of input image data for recording an image on the recording medium. An image processing method, wherein as the density level becomes higher, the formation amount of the low-density dots is gradually increased to a first maximum amount and then gradually decreased, and the low-density dots have a predetermined amount. In the range of the density level higher than the predetermined density level at the time of formation, as the density level becomes higher, the formation amount of the high-density dots is gradually increased to the second maximum amount smaller than the first maximum amount. It is characterized in that the formation amounts of the low-density dots and the high-density dots corresponding to the density level are determined by increasing the number of dots.

The recording apparatus of the present invention is a recording medium based on an image processing unit for executing the above-mentioned image processing method, and the formation amounts of low-density dots and high-density dots determined by the image processing unit. On the other hand, a recording unit for forming the low-density dots and the high-density dots is provided. Further, the recording method of the present invention is based on an image processing step for executing the image processing method, and the formation amount of low-density dots and high-density dots determined in the image processing step, with respect to the recording medium. And a dot forming step of forming the low-density dots and the high-density dots.

Further, the present invention uses a recording section for forming low density dots and high density dots on a recording medium,
A control program for controlling a recording device for recording an image on the recording medium, the unit area of the recording medium depending on a density level of input image data for recording the image on the recording medium. When determining the formation amounts of the low-density dots and the high-density dots with respect to, the formation amount of the low-density dots is first determined as the density level increases.
In the range of the density level higher than a predetermined density level when the low density dots are formed in a predetermined amount, the density level is gradually increased to the maximum amount and then gradually decreased, as the density level increases. The formation amount of the high-density dots is gradually increased to the second maximum amount, which is smaller than the first maximum amount, so that the low-density dots and the high-density dots corresponding to the density level per unit area. And a step of determining an amount of formation, which is executed by a computer. Further, the present invention is a computer-readable storage medium in which this control program is stored.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments of the characteristic constituent parts of the present invention, the embodiments of the basic constituent parts of the present invention will be described first with reference to FIGS. 1 to 10.

In the embodiments described below, a printer will be described as an example of a recording apparatus using the ink jet recording method.

In this specification, "print"
(In some cases, "recording") means not only the formation of significant information such as characters and figures, but also significant insignificance.
In addition, regardless of whether or not it is manifested so that it can be visually perceived by humans, images, patterns,
This also applies when forming a pattern or processing a medium.

Here, the "print medium" is not limited to paper used in a general printing apparatus, but is widely used to receive ink such as cloth, plastic film, metal plate, glass, ceramics, wood, leather, etc. Let's say what is possible.

Further, "ink" (sometimes referred to as "liquid") should be broadly construed in the same way as the definition of "print", and when applied to a print medium, an image, a pattern, A liquid that can be used for forming a pattern or the like, processing a print medium, or treating an ink (for example, solidifying or insolubilizing a coloring material in the ink applied to the print medium).

[Device Main Body] FIGS. 1 and 2 show a schematic structure of a printer using an ink jet recording system. In FIG. 1, the apparatus main body M1 of the printer in this embodiment
The outer shell of 000 is a lower case M1001 and an upper case M10.
02, access cover M1003 and discharge tray M10
It is composed of an exterior member including 04 and a chassis M3019 (see FIG. 2) housed in the exterior member.

The chassis M3019 is composed of a plurality of plate-shaped metal members having a predetermined rigidity, forms the skeleton of the recording apparatus, and holds each recording operation mechanism described later. Further, the lower case M1001 is a device body M1.
000 outer casing and the upper case M1002 form a substantially upper half outer casing of the apparatus main body M1000, respectively, and a hollow having a storage space for storing each mechanism described later by a combination of both cases. It has a body structure. An opening is formed in each of the upper surface and the front surface of the apparatus main body M1000.

Further, one end of the discharge tray M1004 is rotatably held by the lower case M1001 so that the opening formed in the front surface of the lower case M1001 can be opened and closed by the rotation thereof. Therefore, when performing the recording operation, the discharge tray M100
By rotating 4 toward the front side to open the opening, the recording sheets can be discharged from here and the discharged recording sheets P can be sequentially stacked.
Further, the discharge tray M1004 includes two auxiliary trays M
1004a and M1004b are housed, and by pulling out each tray as necessary, the supporting area of the paper can be expanded or reduced in three steps.

One end of the access cover M1003 is rotatably held by the upper case M1002 so that an opening formed on the upper surface can be opened and closed. By opening the access cover M1003, the inside of the main body is opened. It is possible to replace the recording head cartridge H1000 or the ink tank H1900, etc., stored in the cartridge. Although not particularly shown here, the access cover M10
When 03 is opened / closed, the projection formed on the back surface thereof rotates the cover opening / closing lever, and the open / closed state of the access cover can be detected by detecting the rotational position of the lever with a microswitch or the like. It is like this.

On the rear upper surface of the upper case M1002, there are a power key E0018 and a resume key E0019.
LED E0020 is provided, and when the power key E0018 is depressed, L
The ED E0020 is turned on to inform the operator that recording is possible. In addition, LED E0
Reference numeral 020 has various display functions such as changing the blinking method and color, and notifying the operator of printer troubles. Furthermore, the buzzer E0021 (Fig. 7) can be smoothed. When the trouble is solved, the resume key E0019 is pressed to restart the recording.

[Recording Operation Mechanism] Next, the recording operation mechanism in the present embodiment housed and held in the apparatus main body M1000 of the printer will be described.

As the recording operation mechanism in this embodiment, there are an automatic feeding unit M3022 for automatically feeding the recording sheets P into the apparatus main body, and recording sheets P fed one by one from the automatic feeding unit. A conveyance unit M3029 that guides the recording sheet P from the recording position to the discharge unit M3030 while guiding the recording sheet P to the predetermined recording position, and the recording sheet P that is conveyed to the recording position.
And a recovery unit (M5000) that performs recovery processing for the recording unit and the like.

(Recording Unit) Here, the recording unit will be described. The recording unit is a carriage M4001 movably supported by a carriage shaft M4021, and a recording head cartridge H1000 detachably mounted on the carriage M4001. Consists of.

Recording Head Cartridge First, the recording head cartridge used in the recording section will be described with reference to FIGS.

The printhead cartridge H1000 in this embodiment has an ink tank H1900 for storing ink and an ink tank H190 as shown in FIG.
A recording head H1001 that ejects ink supplied from 0 from nozzles according to recording information. The recording head H1001 is of a so-called cartridge type, which is detachably mounted on a carriage M4001 described later.

Recording head cartridge H10 shown here
In 00, in order to enable high-quality color recording of photo quality, as an ink tank, for example, an independent ink tank H1900 for each color of black, light cyan, light magenta, cyan, magenta, and yellow is prepared. As shown in, each of them is detachable from the recording head H1001.

As shown in the exploded perspective view of FIG. 5, the recording head H1001 has a recording element substrate H1100, a first plate H1200, an electric wiring substrate H1300, a second plate H1400, a tank holder H1500,
The flow path forming member H1600, the filter H1700, and the seal rubber H1800 are included.

On the recording element substrate H1100, a plurality of recording elements for ejecting ink on one surface of a Si substrate and electric wiring such as Al for supplying electric power to each recording element are formed by a film forming technique. A plurality of ink channels corresponding to the recording elements and a plurality of ejection ports H1100T are formed by a photolithography technique, and an ink supply port for supplying ink to the plurality of ink channels is formed so as to open on the back surface. Has been done. The recording element substrate H1100 is adhered and fixed to the first plate H1200, and an ink supply port H1201 for supplying ink to the recording element substrate H1100 is formed here. Further, a second plate H1400 having an opening is adhered and fixed to the first plate H1200, and the electric wiring board H13 is provided via the second plate H1400.
00 is held so as to be electrically connected to the printing element substrate H1100. This electric wiring board H1300
Is for applying an electric signal for ejecting ink to the printing element substrate H1100.
The electrical wiring corresponding to 0 and an external signal input terminal H located at the end of the electrical wiring for receiving an electrical signal from the main body
1301 and an external signal input terminal H1301
Is positioned and fixed on the back side of a tank holder H1500 described later.

On the other hand, a flow path forming member H1600 is fixed to a tank holder H1500 which detachably holds the ink tank H1900, for example, by ultrasonic welding, and an ink flow path H1501 extending from the ink tank H1900 to the first plate H1200. Is formed. Further, a filter H1700 is provided at the end of the ink flow path H1501 that engages with the ink tank H1900 on the ink tank side to prevent intrusion of dust from the outside. Further, a seal rubber H1800 is attached to an engaging portion with the ink tank H1900 so that evaporation of ink from the engaging portion can be prevented.

Further, as described above, the tank holder H1
500, flow path forming member H1600, filter H170
0 and the seal rubber H1800, and the recording element portion including the recording element substrate H1100, the first plate H1200, the electric wiring substrate H1300, and the second plate H1400 are bonded to each other by adhesion or the like. Thus, the recording head H1001 is configured.

(Carriage) Next, referring to FIG. 2, a carriage M40 on which the recording head cartridge H1000 is mounted.
01 will be described.

As shown in FIG. 2, a carriage M4001
Is engaged with the carriage M4001 and the recording head H10.
A carriage cover M4002 for guiding 01 to a predetermined mounting position on the carriage M4001, and a head set lever M4007 that engages with the tank holder H1500 of the recording head H1001 and presses the recording head H1001 to set it in the predetermined mounting position. Is provided. That is, the headset lever M4007 is rotatably provided on the carriage M4001 with respect to the headset lever shaft, and a spring-biased headset plate (not shown) is provided at an engaging portion with the recording head H1001. The recording head H1001 is mounted on the carriage M4001 while being pressed by the spring force.

A contact flexible printed cable (see FIG. 7, hereinafter, contact FPC) is provided at another engaging portion of the carriage M4001 with the recording head H1001.
E) is provided and contact FPC E
Contact part on 0011 and contact part (external signal input terminal) H1301 provided on the recording head H1001
And are in electrical contact with each other, so that various kinds of information for recording can be transmitted and received, and power can be supplied to the recording head H1001.

An elastic member such as rubber (not shown) is provided between the contact portion of the contact FPC E0011 and the carriage M4001, and the contact portion is formed by the elastic force of this elastic member and the pressing force of the headset lever spring. A reliable contact with the carriage M4001 is made possible. Furthermore, the contact FPC
E0011 is connected to a carriage substrate E0013 mounted on the back surface of the carriage M4001 (see FIG. 7).

[Scanner] The printer in this embodiment can also be used as a reading device by mounting a scanner on the carriage M4001 instead of the recording head cartridge H1000 described above.

This scanner is a carriage on the printer side.
It moves in the main scanning direction together with the M4001 and reads the document image fed in place of the recording medium in the process of moving in the main scanning direction. The reading operation in the main scanning direction and the sub scanning of the document By alternately performing the feeding operation in the direction, the image information of one original can be read.

FIGS. 6 (a) and 6 (b) show a scanner M600 for explaining the schematic structure of the scanner M6000.
It is a figure which shows 0 upside down.

As shown, the scanner holder M6001
Has a substantially box shape, and the optical system and processing circuit necessary for reading are housed inside. Further, when the scanner M6000 is mounted on the carriage M4001, the reading section lens M60 is provided in a portion facing the document surface.
06 is provided, and the lens M6006 converges the reflected light from the document surface to the internal reading unit to read the document image. On the other hand, the illumination unit lens M6005 has a light source (not shown) inside, and the light emitted from the light source is applied to the document through the lens M6005.

The scanner cover M6003 fixed to the bottom of the scanner holder M6001 is a scanner holder M6.
The inside of 001 is fitted so as to block light, and the louver-shaped gripping portion provided on the side surface improves the operability of attachment / detachment to / from the carriage M4001. Scanner holder M60
The external shape of 01 is substantially the same as that of the recording head H1001, and can be attached to and detached from the carriage M4001 by the same operation as that of the recording head cartridge H1000.

The scanner holder M6001 accommodates a substrate having a reading processing circuit, and a scanner contact PCB connected to the substrate is provided so as to be exposed to the outside, and the scanner M6000 is mounted on the carriage M4001. Scanner contact PC when installed
B M6004 comes into contact with the contact FPC E0011 on the carriage M4001 side, and the substrate is moved to the carriage M4.
It is adapted to be electrically connected to the control system on the main body side via 001.

[Structure of Electric Circuit of Printer] Next, the electric circuit structure in the embodiment of the present invention will be described. Figure 7
FIG. 3 is a diagram schematically showing an example of the overall configuration of an electric circuit in this embodiment.

The electric circuit in this embodiment is mainly composed of a carriage board (CRPCB) E0013 and a main PC.
It is composed of a B (Printed Circuit Board) E0014, a power supply unit E0015, and the like. Here, the power supply unit E0015 is connected to the main PCB E0014 and supplies various driving power supplies. Also,
The carriage board E0013 is a carriage M4001.
2 is a printed circuit board unit mounted on (FIG. 2), which functions as an interface for exchanging signals with the recording head through the contact FPC E0011, and also the encoder sensor E as the carriage M4001 moves.
A change in the positional relationship between the encoder scale E0005 and the encoder sensor E0004 is detected based on the pulse signal output from 0004, and the output signal is output to the main PCB E0014 through the flexible flat cable (CRFFC) E0012.

Further, the main PCBE0014 is a printed circuit board unit which controls the drive control of each part of the ink jet recording apparatus in this embodiment, and the paper edge detection sensor (P
E sensor) E0007, ASF (automatic paper feeder) sensor E0009, cover sensor E0022, parallel interface (parallel I / F) E0016, serial interface (serial I / F) E0017, resume key E0019, LED E0020, power key E
I / O ports for 0018, buzzer E0021, etc. are provided on the substrate. Furthermore, a motor (CR motor) E0 which is a drive source for main-scanning the carriage M1400
001, a motor (LF motor) E0002 serving as a drive source for conveying the recording medium, a motor (PG motor) E used for both the rotation operation of the recording head and the feeding operation of the recording medium
In addition to controlling these drives by being connected to 0003, an empty sensor E0006, a GAP sensor E000
8, PG sensor E0010, CRFFC E0012,
It has a connection interface with the power supply unit E0015.

FIG. 8 is a block diagram showing the internal structure of the main PCB E0014. In the figure, E1001 is C
This is a PU, and this CPU E1001 is a clock generator (CG) internally connected to an oscillator circuit E1005.
E1002 has its output signal E1019 to generate a system clock. In addition, the ROM E1004 and ASIC (Applicatio
n Specific Integrated Circuit) ASI connected to the E1006 according to the program stored in the ROM.
Control of C E1006, input signal E101 from power key
7, the input signal E1016 from the resume key, the cover detection signal E1042, the head detection signal (HSEN
S) The state of E1013 is detected, and the buzzer E0021 is driven by a buzzer signal (BUZ) E1018, and an ink emptyness detection signal (INKS) E1011 connected to the built-in A / D converter E1003 and a temperature detection signal by a thermistor. While the state of (TH) E1012 is detected, various other logical operations and condition judgments are performed to control the drive of the inkjet recording apparatus.

The head detection signal E1013 is sent from the recording head cartridge H1000 to the flexible flat cable E0012, the carriage substrate E0013 and the contact flexible print cable E0011.
Is a head mounted detection signal that is input via the in-empty detection signal E1011.
Analog signal and temperature detection signal E output from 0006
Reference numeral 1012 is an analog signal from a thermistor (not shown) provided on the carriage substrate E0013.

Reference numeral E1008 denotes a CR motor driver which uses a motor power source (VM) E1040 as a drive source
CR motor control signal E1036 from IC E1006
, The CR motor drive signal E1037 is generated, and C
The R motor E0001 is driven. E1009 is LF / P
A G motor driver, which uses a motor power source E1040 as a drive source and generates an LF motor drive signal E1035 in accordance with a pulse motor control signal (PM control signal) E1033 from an ASIC E1006, which drives the LF motor and also drives a PG motor. The drive signal E1034 is generated to drive the PG motor.

E1010 is a power supply control circuit,
Power supply to each sensor having a light emitting element is controlled according to a power supply control signal E1024 from C E1006.
Parallel I / F E0016 is ASIC E1006
The parallel I / F signal E1030 from the device is transmitted to the parallel I / F cable E1031 connected to the outside, and the signal of the parallel I / F cable E1031 is transmitted to the ASIC.
Transmit to E1006. Serial I / F E0017
Is the serial I / F signal E from the ASIC E1006.
1028 is transmitted to the serial I / F cable E1029 connected to the outside, and a signal from the cable E1029 is transmitted to the ASIC E1006.

On the other hand, from the power supply unit E0015, the head power supply (VH) E1039 and the motor power supply (VM) E
1040, the logic power supply (VDD) E1041 is supplied. In addition, the head power supply O from the ASIC E1006
An N signal (VHON) E1022 and a motor power supply ON signal (VMOM) E1023 are input to the power supply unit E0015 to control ON / OFF of the head power supply E1039 and the motor power supply E1040, respectively. Power supply unit E
Logic power supply (VDD) E10 supplied from 0015
41 is the main PC after the voltage is converted if necessary.
B E0014 is supplied to each part inside and outside.

The head power supply signal E1039 is sent to the flexible flat cable E0011 after being smoothed on the main PCB E0014 and used for driving the recording head cartridge H1000. E100
Reference numeral 7 denotes a reset circuit, which detects a decrease in the logic power supply voltage E1041 and detects the CPU E1001 and the ASIC E1.
A reset signal (RESET) E1015 is supplied to 006 to perform initialization.

This ASIC E1006 is a one-chip semiconductor integrated circuit, and the CP via the control bus E1014.
Controlled by the U E1001, the CR motor control signal E1036, the PM control signal E1033, the power supply control signal E1024, the head power ON signal E1022, the motor power ON signal E1023, etc. are output, and the parallel I / F E0016 and the serial I / F are output. F E0017
In addition to exchanging signals with the PE sensor E0007, a PE detection signal (PES) E1025 from the PE sensor E0007, an ASF sensor E
ASF detection signal (ASFS) E102 from 0009
6. Detecting the states of the GAP detection signal (GAPS) E1027 from the sensor (GAP) sensor E0008 for detecting the gap between the recording head and the recording medium and the PG detection signal (PGS) E1032 from the PG sensor E0010, Data representing the state is transmitted to the CPU E1001 through the control bus E1014, and based on the input data, the CPU E1001 controls the driving of the LED driving signal E1038 to blink the LED E0020.

Further, the encoder signal (ENC) E10
20 is detected to generate a timing signal, and the head control signal E1021 is used to generate the recording head cartridge H100
It interfaces with 0 and controls the recording operation. Here, the encoder signal (ENC) E1020 is an output signal of the CR encoder sensor E0004 input through the flexible flat cable E0012. Further, the head control signal E1021 corresponds to the flexible flat cable E0012 and the carriage substrate E001.
3 and the contact FPC E0011 to the recording head H1000.

FIG. 9 is a block diagram showing an internal configuration example of the ASIC E1006.

In the figure, regarding the connections between the blocks, only the flow of data relating to the control of the head and the mechanical parts of each part, such as recording data and motor control data, is shown, and the registers incorporated in each block are shown. In order to avoid complication of description in the drawings, control signals and clocks for reading and writing, and control signals for DMA control are omitted.

In the figure, E2002 is a PLL controller, and as shown in FIG. 9, an ASIC E1 is supplied by a clock signal (CLK) E2031 and a PLL control signal (PLLON) E2033 output from the CPU E1001.
A clock (not shown) that feeds most of 006
To occur.

Further, E2001 is a CPU interface (CPU I / F), and a reset signal E1015,
Soft reset signal (PDWN) E2032 and clock signal (CLK) E2 output from CPU E1001
031 and the control signal from the control bus E1014,
As described below, control such as register read / write for each block, clock supply to some blocks, acceptance of interrupt signals, etc. (all not shown) are performed, and interrupt signals (IN
T) E2034 is output to notify the occurrence of an interrupt in the ASIC E1006.

Reference numeral E2005 denotes a DRAM, which serves as a data buffer for recording, which is a reception buffer E2010,
Work buffer E2011, print buffer E201
4. A motor control buffer E for motor control, which has areas such as a data buffer E2016 for expansion.
2023, and a scanner capture buffer E2024, a scanner data buffer E2026, and a sending buffer E20, which are used in place of the recording data buffers described above, as buffers used in the scanner operation mode.
28 areas.

Further, this DRAM E2005 has a CP
It is also used as a work area necessary for the operation of the UE1001. That is, E2004 is a DRAM control unit, and the CPU E1001 via the control bus
Access to E2005 and DMA control unit E described later
The access from 2003 to the DRAM E2005 is switched to read / write from / to the DRAM E2005.

The DMA control unit E2003 receives a request (not shown) from each block, and outputs an address signal, a control signal (not shown) and write data E2038, E2041, E2044, E2 in the case of a write operation.
053, E2055, E2057, etc.
Output to 2004 for DRAM access. In the case of reading, read data E2040, E2043, E2045, E20 from the DRAM control unit E2004.
51, E2054, E2056, E2058, E205
9 is passed to the requesting block.

Further, E2006 is IEEE 1284I /
F, CPU via CPU I / FE 2001
Parallel I / F E0016 is controlled by the control of E1001.
Through a bidirectional communication interface with an external host device (not shown), and a parallel I / F during recording.
Received data from E0016 (PIF received data E2
036) is transferred to the reception control unit E2008 by the DMA processing, and the DRAM E20
The data (1284 transmission data (RDPIF) E2059) stored in the transmission buffer E2028 in 05 is D
It is transmitted to the parallel I / F by MA processing.

The E2007 is a universal serial bus (USB) I / F, which is controlled by the CPU E1001 via the CPU I / F E2001.
A bidirectional communication interface with an external host device (not shown) is performed through the FE0017, and at the time of printing, reception data (USB reception data E2037) from the serial I / F E0017 is received by the reception control unit E by DMA processing.
It is handed over to the 2008 and the DRAM is read at the time of the scanner reading.
Data stored in the transmission buffer E2028 in E2005 (USB transmission data (RDUSB) E2058)
Is transmitted to the serial I / F E0017 by the DMA processing. The reception controller E2008 has a 1284 I / F E2.
006 or received data (WDIF) E203 from the selected I / F of the USB I / F E2007
8) is written in the reception buffer write address managed by the reception buffer control unit E2039. E2009 is a compression / expansion DMA controller, CPU I / F E20
Under the control of the CPU E1001 via 01, the reception data (raster data) stored in the reception buffer E2010 is read from the reception buffer read address managed by the reception buffer control unit E2039, and the data (RDWK) E2040 is designated. It is compressed / decompressed according to the mode and is written in the work buffer area as a recording code string (WDWK) E2041.

E2013 is a recording buffer transfer DMA controller, which is a CPU via the CPU I / F E2001.
Under the control of E1007, the print code (RDWP) E2043 on the work buffer E2011 is read out, and each print code is adapted to the print buffer E201 which is suitable for the data transfer order to the print head cartridge H1000.
Rearranged to the address on 4 and transferred (WDWP E204
4) Do. Further, E2012 is a work clear DMA controller, which is a CP via the CPU I / F E2001.
The designated work fill data (WDWF) E2042 is repeatedly written in the area on the work buffer where the transfer by the recording buffer transfer DMA controller E2013 is completed under the control of the U E1001.

Reference numeral E2015 denotes a recording data expansion DMA controller, which is a CPU via the CPU I / F E2001.
Under the control of E1001, the recording code rearranged and written in the print buffer and the expansion data written in the expansion data buffer E2016 are triggered by the data expansion timing signal E2050 from the head controller E2018. Read and develop record data (RDHD
G) Write E2045 to column buffer write data (WDH
DG) E2047 is written in the column buffer E2017. Here, the column buffer E2017 is an SRAM that temporarily stores transfer data (expanded print data) to the print head cartridge H1000, and a handshake signal (not shown) between the print data expansion DMA controller E2015 and the head control unit E2018. ) Is shared by both blocks.

E2018 is a head controller, which is a CPU I /
By controlling the CPU E1001 via the F E2001, the print head cartridge H is sent via a head control signal.
In addition to the interface with 1000 or the scanner, the recording data expansion DM based on the head drive timing signal E2049 from the encoder signal processing unit E2019.
Data expansion timing signal E2 for A controller
050 is output.

At the time of printing, the expanded recording data (RDHD) E2048 is read from the column buffer in accordance with the head drive timing signal E2049, and the data is output to the recording head cartridge H1000 as the head control signal E1021. In the scanner reading mode, the captured data (WDHD) E2053 input as the head control signal E1021 is DR.
Scanner acquisition buffer E202 on AM E2005
DMA transfer to 4. E2025 is a scanner data processing DMA controller, and CPU I / F E2001
By the control of the CPU E1001 via the CPU, the read-out buffer read data (RDAV) E2054 stored in the scanner read-in buffer E2024 is read and processed data (WDAV) E205 obtained by performing processing such as averaging is read.
5 is written in the scanner data buffer E2026 on the DRAM E2005. E2027 is scanner data compression
The DMA controller controls the CPU E1001 via the CPU I / F E2001 to process the processed data (RDYC) E20 on the scanner data buffer E2026.
56 is read out, data compression is performed, and compressed data (W
DYC) E2057 is written and transferred to the sending buffer E2028.

Reference numeral E2019 denotes an encoder signal processing unit which receives the encoder signal (ENC) and receives the CPU E1.
In addition to outputting the head drive timing signal E2049 according to the mode determined by the control of 001, the information about the position and speed of the carriage M4001 obtained from the encoder signal E1020 is stored in the register, and the CPU E
1001. The CPU E1001 determines various parameters in the control of the CR motor E0001 based on this information. Further, E2020 is a CR motor control unit, which is a CPU via the CPU I / F E2001.
By the control of E1001, the CR motor control signal E103
6 is output.

A sensor signal processing unit E2022 is a detection signal E1033, E1025, E1026, which is output from the PG sensor E0010, PE sensor E0007, ASF sensor E0009, GAP sensor E0008, and the like.
Upon receiving E1027, these sensor information are sent to the CPUE10 according to the mode defined by the control of the CPUE1001.
01, the sensor detection signal E2052 to the LF / PG motor control DMA controller E2021
Is output.

The DMA controller E2021 for controlling the LF / PG motor is a CP via the CPU I / F E2001.
Under the control of the U E1001, the pulse motor drive table (RDPM) E2051 is read from the motor control buffer E2023 on the DRAM E2005 to output the pulse motor control signal E1033. In addition, depending on the operation mode, the sensor detection signal is used as a control trigger pulse. The motor control signal E1033 is output. Also, E203
An LED control unit 0 outputs an LED drive signal E1038 under the control of the CPU E1001 via the CPU I / F E2001. Further, E2029 is a port control unit, and CP via CPU I / F E2001.
Head power ON signal E1 by control of U E1001
022, the motor power supply ON signal E1023, and the power supply control signal E1024 are output.

[Printer Operation] Next, the operation of the ink jet recording apparatus according to the embodiment of the present invention configured as described above will be described with reference to the flowchart of FIG.

When the apparatus main body 1000 is connected to the AC power source, first, in step S1, a first initialization process of the apparatus is performed. In this initialization processing, the ROM and R of this device are
Check the electric circuit system such as AM check,
Confirm that this device can operate electrically normally.

Next, in step S2, the apparatus main body M100
Power key E001 provided on the upper case M1002 of 0
8 is turned on, it is judged whether the power key E00
When 18 is pressed, the process proceeds to the next step S3, where the second initialization process is performed.

In this second initialization processing, various drive mechanisms and recording heads of this apparatus are checked. That is, when initializing various motors and reading head information, it is confirmed whether or not the device can operate normally.

Next, in step S4, an event is waited. That is, the present apparatus monitors a command event from an external I / F, a panel key event by a user operation, an internal control event, and the like, and when these events occur, the process corresponding to the event is executed.

For example, when the print command event from the external I / F is received in step S4, the process proceeds to step S5, and when the power key event by the user operation occurs in the same step, the process proceeds to step S10. If any other event occurs in the same step, the process proceeds to step S11. Here, in step S5, the print command from the external I / F is analyzed, and the specified paper type,
The paper size, print quality, paper feeding method, etc. are judged, and the data showing the judgment result is stored in the RAM E2005 in the present apparatus, and the process proceeds to step S6. Next, in step S6, the paper feeding is started by the paper feeding method specified in step S5, the paper is fed to the recording start position, and the process proceeds to step S7. In step S7, the recording operation is performed. In this recording operation, the recording data sent from the external I / F is temporarily stored in the recording buffer, and then the CR motor E0001
Is started to start moving the carriage M4001 in the main scanning direction, and the print data stored in the print buffer E2014 is supplied to the print head H1001 to print one line and print data for one line. When the recording operation of 1 is completed, the LF motor E0002 is driven to rotate the LF roller M3001 and feed the paper in the sub-scanning direction. After that, the above operation is repeatedly executed, and when the recording of the recording data for one page from the external I / F is completed, the process proceeds to step 8.

In step S8, the LF motor E0002
Is driven, the paper discharge roller M2003 is driven, and the paper is repeatedly fed until it is determined that the paper has been completely discharged from the apparatus. At the end, the paper is completely discharged onto the paper discharge tray M1004a. Becomes

Next, in step S9, it is judged whether or not the recording operation of all the pages to be recorded is completed, and if the pages to be recorded remain, the process returns to step S5. Repeat the operation from S5 to S9,
When the recording operation of all pages to be recorded is completed, the recording operation ends, and then the process proceeds to step S4 to wait for the next event.

On the other hand, in step S10, the printer end process is performed to stop the operation of this apparatus. In other words, in order to turn off the power of various motors and heads, the power is turned off and then the power is turned off in step S4.
Go to and wait for the next event.

At step S11, event processing other than the above is performed. For example, processing corresponding to a recovery command from various panel keys of the apparatus or an external I / F or a recovery event internally generated is performed. After the processing is completed, the process proceeds to step S4 to wait for the next event.

One mode in which the present invention is effectively used is a mode in which the heat energy generated by the electrothermal converter is used to cause film boiling in the liquid to form bubbles.

(First Embodiment) Next, the first embodiment of the characteristic components of the present invention will be described.

[Head Structure and Recording Method] In this embodiment, as the recording head H1001 mounted on the carriage M4001, a recording head H having a structure as shown in FIGS. 11 to 13 is used. In the recording head H of this example, a plurality of ejection ports P capable of ejecting ink
Are formed so as to form two rows (hereinafter, also referred to as “nozzle rows”) L1 and L2. The nozzle rows L1 and L2 extend in the sub-scanning direction of the arrow B through which the recording medium is conveyed. The ejection ports P forming the nozzles have a pitch Py at an interval corresponding to 600 dpi in each of the nozzle rows L1 and L2.
As a result, 128 pieces (for 128 nozzles) each are formed. Further, the ejection openings P of the nozzle row L1 and the ejection openings P of the nozzle row L2 are displaced in the sub-scanning direction of the arrow Y by a half pitch (Py / 2) corresponding to 1200 dpi. Arrow X
Is the main scanning direction in which the recording head H moves back and forth. Then, by ejecting the same color ink from the ejection ports P of a total of 256 in these two rows, it is possible to record an image with a dot density of 1200 dpi in the sub-scanning direction. Therefore, the recording resolution in the sub-scanning direction is double that in the case where only one of the nozzle rows L1 and L2 is provided. In the case of this example, the diameter of the dot formed by the ink ejected from the nozzle is set to 45 μm for the reason described later. The interval corresponding to 1200 dpi is 21.7 μm.

Further, in the case of this example, the multi-pass printing method is adopted and the pixels on the same raster are printed by using a plurality of nozzles. For example, when the 8-pass unidirectional printing method or the 8-pass bidirectional printing method is adopted, the same raster is printed by using eight different nozzles by eight passes (scans) of the print head H. It is possible to suppress the influence of the image disturbance caused by the variation in the ink ejection direction at the nozzles. In the case of the unidirectional recording method, the recording operation is performed only when the recording head H scans in one direction, and in the case of the bidirectional recording method, the recording operation occurs when the recording head H scans in both directions.

Further, in the case of this example, as will be described later, the recording resolution in the main scanning direction is set to the basic recording density 1200d.
The recording resolution in the main scanning direction and the sub scanning direction is (2400 dpi × 1200).
dpi). Halftone (halftone level) is recorded using the error diffusion method (ED).

In the case of this example, the resolution of the image data input from the host device to the recording device is (600 ppi ×
It is 600 ppi). The recording device is shown in FIG.
As shown in (b), (2400 dpi × 1200 dpi)
In order to correspond to the recording mode of 4, the gradation expression is performed for each 4 × 2 recording area having 4 pixels in the main scanning direction and 2 pixels in the sub scanning direction. In other words, gradation expression is performed for each unit region (unit area) corresponding to a resolution of 600 ppi × 600 ppi. Note that the number of gradations represented in each unit area is 9 gradations of gradation levels 0 to 8. In the case of this example, six recording heads H are provided as shown in FIG.
Cyan (C), magenta (M), yellow (Y), black (K) ink, light cyan (Lc),
Light magenta (Lm) ink is ejected. The cyan (C), magenta (M), yellow (Y), and black (K) inks are dark inks having a relatively high dye density, and the light cyan (Lc) and light magenta (Lm) inks are dark inks. It is a light ink that has a density of 1/6 of the ink and a relatively low dye density. In this way, a color image can be recorded by ejecting different inks from each recording head H in which the two nozzle rows L1 and L2 are formed. Assuming that the recording mode is (1200 dpi × 1200 dpi), as shown in FIG. 22A, a 2 × 2 recording area (600 ppi × 600 ppi resolution) having two pixels in the main scanning direction and two pixels in the sub scanning direction. The gradation expression is performed for each unit area corresponding to.

In FIG. 13, h is a heater (electrothermal converter), which generates thermal energy used as ejection energy of the ink droplet I'in response to a drive signal. Ink I in the nozzle is generated by the heat energy of the heater h.
The film boiling occurs in the ink, and the foaming energy at that time causes the ink droplet I ′ to be ejected from the ejection port P.

[Relationship Between Amount of Deposition and Density] Next, the relationship between the amount of ink ejected onto the recording medium to form dots and the recording density will be described with reference to FIG.

Here, when the unit area corresponding to the resolution of 1200 dpi × 1200 dpi as shown in FIG. 22 is defined as one pixel, the dot amount is a dot having a size enough to fill the one pixel. It is an index showing how much (number) is formed with respect to the one pixel, and the ink ejection amount when one dot is formed per pixel is 100%. Therefore, the ink amount when two dots are formed per pixel is 200%, and the ink ejection amount when three dots are formed per pixel is 300%. As is clear from this, in FIG.
Since one dot is formed for each unit area of i × 1200 dpi, the implantation amount is 100%. In FIG. 22B, two dots are formed for each unit area of 1200 dpi × 1200 dpi. Therefore, the driving amount is 200%.

The method of defining the driving amount is not limited to this, and may be defined as follows. That is, as shown in FIG. 22, 600 dp
When the number of dots required to fill the unit area corresponding to the resolution of i × 600 dpi is formed in the unit area, the ejection amount may be defined as 100%. Specifically, as shown in FIG. 22A, 600 dpi × 600
When the four dots are formed in the unit area corresponding to the resolution of dpi, the ejection amount is set to 100%, and FIG.
When 8 dots are formed in a unit area corresponding to a resolution of 600 dpi × 600 dpi as shown in 2 (b), the amount of implantation is 200%. Therefore, 600d
5 in a unit area corresponding to a resolution of pi × 600 dpi
When the dots are formed, the shot amount is 125%, and when the seven dots are formed in the unit area, the shot amount is 175%.

As described above, in the present specification, the "implantation amount" is a predetermined unit area (such as a unit area corresponding to a resolution of 1200 dpi × 1200 dpi, a unit area corresponding to a resolution of 600 dpi × 600 dpi, etc.). Number of dots required to fill the unit area (N
When the number of pieces is formed for the unit area, the implantation amount is defined as 100%. Therefore, when 2N dots are formed in a predetermined unit area (unit area) that is set in advance, the amount of implantation is 200%, and 1.75N dots are formed in a predetermined unit area (unit area) that is set in advance. When the is formed, the driving amount is 175%.

As shown in FIG. 14, in the case of dark ink, the density can be increased almost linearly when the ink ejection amount is 0% to 100%. However, if the implantation amount exceeds 125%, the density hardly rises. Further, if the amount of ejection is 200% or more, not only the density is increased but the density is decreased, and the image quality is deteriorated due to the overflow of ink. Therefore, 2
Regarding the total amount of ink ejected during recording of the secondary color and tertiary color or more, it can be seen that there is not much merit in terms of image quality even if the ink is ejected by 125% or more.

On the other hand, in the case of the light ink, the density increase can be achieved almost linearly when the ink impact amount is 0% to 200%. Furthermore, if the amount of ejection is increased to 300%, the density itself hardly rises, and the ink may overflow from the recording medium to cause image quality deterioration. Therefore, as for the light ink, as long as the ink impact amount is used in the range of 0% to more than 200% and less than 300%, the density increase and the excellent gradation can be obtained as compared with the normal use of 100%. It will be.

In the present embodiment, the amount of dark ink and light ink ejected per predetermined unit area determined in advance is determined using a look-up table (LUT).

FIG. 15 is an explanatory diagram of a conventional LUT.
This LUT gradually increases the amount of light ink ejected according to the input gradation level (density level of input image data), and after setting the amount of ejection to the maximum amount of 100% to 130%, Gradually decrease. Also, with the input gradation level when the maximum amount of light ink is ejected as a boundary, the dark ink ejection starts, and the dark ink ejection amount is gradually increased according to the input gradation level. When it reaches the maximum, the amount of dark ink ejected becomes the maximum.

FIG. 16 shows an LU used in this embodiment.
It is explanatory drawing of T. In this LUT, the maximum ejection amount of light ink is 200% (first maximum amount). Therefore, as compared with the case of using the conventional LUT of FIG. 15, the input gradation level when the maximum amount of light ink is ejected increases and the dot density at that time also increases. Therefore, the input gradation level at the time of starting ejection of dark ink is increased. As a result, when the amount of light ink ejected is set to the maximum of 200% at the time of starting ejection of dark ink, as shown in the graph on the right side of FIG.
C2 has a relatively small difference (contrast) between the density of 0% and the density of the dark ink. Therefore, it is possible to make the dots inconspicuous and to reduce the graininess in the medium density region where the dark ink starts to be ejected. On the other hand, in the case of using the conventional LUT of FIG. 15, when the dark ink is started to be ejected and the ejection amount of the light ink is set to 100% of the maximum, as shown in the graph on the left side of FIG. Difference between the density of 100% light ink and dark ink (contrast)
Is relatively large C1 (> C2). As a result, the dots become conspicuous and the graininess becomes large in the medium density area where the dark ink starts to be ejected.

Further, when the LUT of FIG. 16 is used, since the input gradation level at the time of starting the ejection of the dark ink is increased, the change gradient of the ejection amount of the dark ink with respect to the input gradation level is as shown in FIG. This is larger than when using a conventional LUT. Therefore, as shown in FIG. 16, the middle density area after the dark ink is started to be ejected, that is, the density area (tone level width) A in which graininess is likely to be given is narrowed,
Moreover, the density region (tone level width) B on which the dark ink is ejected can be narrowed. As a result, it is possible to print a high-quality image with less graininess in all the density regions as compared with the case of using the conventional LUT of FIG. Further, in FIG. 16, the maximum amount of dark ink ejected is 1
It is set to 00% (second maximum amount).

As described above, in this embodiment, the LUT as shown in FIG. 16 is used when determining the formation amounts of the light dots (low density dots) and the dark dots (high density dots) for a predetermined unit area. In the LUT, the maximum ejection amount is 200% (first maximum amount) for the light ink whose density increases linearly up to at least 200% ejection amount.
Then, in the dark ink in which the density increases linearly up to the ejection amount of 100%, the maximum ejection amount is set to 100% (second maximum amount). This makes it possible to widen the range of gradation levels (density levels) that are formed only with light ink that is less prominent in graininess, while creating a gradation level (density level) that dark ink in which graininess is relatively more conspicuous is formed. Since the width of the image can be reduced, the graininess of the entire image can be reduced.

In the present invention, the predetermined gradation level at which the dark ink is started to be ejected is higher than the gradation level corresponding to the case where the maximum amount of light ink is ejected, as shown in FIG. It is preferable that the gradation level is low. That is, it is preferable to start the dark ink ejection before the light ink ejection amount reaches the first maximum amount (200%). However, if the gradation level at which the dark ink starts to be ejected is too low, that is, if the dark ink is ejected when the amount of light ink ejected is small, the graininess cannot be reduced. Therefore, as the predetermined gradation level at which the dark ink ejection is started, it is preferable to set at least the gradation level after the light ink ejection amount reaches 175%. When the dark ink is started to be ejected from the gradation level at which the light ink is ejected at 175% or more, the width of the density region formed by only the light ink is wider than in the conventional case, and the graininess is more noticeable. Since the density area where the dark dots are formed is narrowed, the graininess is reduced as a whole. In this way, by setting the predetermined gradation level at which the dark ink ejection is started to a gradation level lower than the gradation level corresponding to the case where the maximum amount of light ink is ejected, recording from light dots is performed. The color mixture at the joint to the recording by the dark dots becomes extremely smooth, and the quality of the recorded image becomes extremely high.

FIG. 17 is a diagram comparing the conventional LUT with the LUT used in the present invention. In particular, density areas A (medium density area after dark ink has begun to be ejected, that is, a density area where graininess tends to be noticeable), B (density area where dark ink is ejected), and corresponding density areas A ′ in the conventional LUT. , B'are compared. In the case of this example, the widths of the gradation levels corresponding to the areas A, A ′, B, and B ′ are A = 50, A ′ = 100, B = 95, and B ′ = 1.
75, and A <A 'and B <B'. As is apparent from the above, in the present invention, the density region (tone level width) B on which dark ink is ejected is made smaller and the density region (tone level width) A in which graininess is more noticeable than in the prior art. The graininess of dots is reduced by narrowing.

As the LUT used in this embodiment, as shown in FIG. 16, the ejection of dark ink is started before the ejection amount of light ink reaches the first maximum amount (200%). 17 may be used, or, as shown in FIG. 17, when the amount of light ink ejected reaches the first maximum amount (200%), ejection of dark ink may be started. As described above, in the present embodiment, as the predetermined gradation level (density level) at which the dark ink ejection is started, the density level equal to or lower than the density level corresponding to the first maximum amount which is the maximum ejection amount of the light ink, Alternatively, it may be set to a density level exceeding the density level corresponding to the first maximum amount. That is, the predetermined gradation level (density level) at which the dark ink ejection is started may be set to a density level higher than the predetermined density level when a predetermined amount of low-density dots are formed.

[Relationship between Pixel and Dot] When the recording resolution is 1200 dpi × 1200 dpi,
As shown in FIG. 19, the area A per pixel is 448 μm ²
Becomes Therefore, the minimum dot diameter required to fill one pixel is 30 μm, which is the diagonal distance of one pixel.
And the dot area S0 is 706.5 μm ² . This value is about 1.5 times the area per pixel (15
8%) or more. However, in reality, it is necessary to add about 10 μm as a mechanical error of the printer (such as ink landing accuracy in the recording head and paper feed error). Therefore, the optimum dot diameter is 40 μm. The area of the dot is 1257 μm ² , which is about 2.8 times the area A per pixel. In this way, the recording resolution is 12
In a high-resolution printer of 00 dpi × 1200 dpi or more, it is necessary to determine the dot diameter so that the dot area is 2.0 times or more per unit pixel area in order to secure the required resolution. If the dot diameter does not satisfy such a condition, the area factor is not sufficient, so banding (density unevenness in the main scanning direction), etc. may occur due to irregularities in dot landing accuracy, paper feed errors, and carriage movement errors. It is easy to happen.

20 and 21 are diagrams showing the relationship between the unit pixel area corresponding to the resolution and the dot area corresponding to the dot diameter. In this embodiment, the dot diameter is set to 45 μm so that one pixel can be sufficiently filled with one pixel in the resolution of 1200 dpi × 1200 dpi shown in FIG. From the area factor, the optimum resolution for a dot diameter of 45 μm is 120.
It becomes 0 dpi × 1200 dpi. In that case, the amount of ejected ink per pixel is 100%.

However, in the case of this embodiment, as described above, in order to reduce the graininess particularly in the medium density region, it is necessary to increase the maximum amount of light ink shot to 200%. Therefore, in the present embodiment, as shown in FIG. 22B, the resolution in the main scanning direction is set to 2400 dpi, which is twice 1200 dpi, resulting in a unit area in the main scanning direction (1200 dpi × 1200 d).
The dot ejection amount per 1 pixel area at the pi resolution) was doubled. Therefore, 2400 dpi
When a dot is printed at each of 8 pixels of 4 × 2 at a recording resolution of × 1200 dpi, it is 12
The ink ejection amount per pixel in the resolution of 00 dpi × 1200 dpi is 200%. And
In this case, dot area of 45 μm dot area 1590 μm
² is about 7 times the area 224 μm ² per pixel in the resolution of 2400 dpi × 1200 dpi.

[Method of Processing Input Image Data] FIG. 23 shows an image processing unit 230 for processing input image data.
3 is a functional block diagram for explaining the function of FIG. The image processing unit 230 is composed of a color processing unit 210 and a quantization unit 220, and has 8 bits (256 bits) for each color of R, G, and B that is input.
The image data of (gradation) is output as 4-bit data of each color of C, M, Y, K, Lc, and Lm. Further, the color processing section 210 is configured to include a color space conversion processing section 211, a color conversion processing section 212, and an output Γ processing section 213.

In such an image processing unit 230, the bit data of each color of R, G, B input from the external host device is first processed by the three-dimensional LUT of the color space conversion processing unit 211.
Is converted into 8-bit data of each color of R ', G', and B '. This processing is also called pre-stage color processing, and performs conversion processing for correcting the difference between the color space (color space) of the input image and the reproduction color space of the output device.

Next, R ', G', which have been subjected to the preceding color processing,
The 8-bit data of each color B ′ is converted into 8-bit data of each color of C, M, Y, and K by the three-dimensional LUT of the color conversion processing unit 212. This process is also called a post-stage color process, and is a color conversion process for converting an input RGB color to an output CMYK color. Furthermore, C (cyan) and M
The (magenta) data is separated into dark ink data and light ink data. At that time, the data for C (dark cyan) and Lc (light cyan) are shown in FIG. 16 or FIG.
Are separated as in the relationship of. Similarly, for the data for M (dark magenta) and Lm (light magenta), the ejection amounts of these dark and light inks are shown in FIG. 16 or FIG.
Separated as in the 7 relationship. Note that the LUTs in FIGS. 16 and 17 are 8 pixels (4 × 2) in FIG. 22B.
A predetermined unit area (600 pp
For each unit area corresponding to a resolution of i × 600 ppi),
Determine the amount of dark and light ink shot. Therefore, FIG.
The horizontal axis of the LUT of FIG. 6 and FIG. 17 is a value obtained by averaging the input gradation levels for every 8 pixels (4 × 2) included in the predetermined unit area.

C, M, Y, K, L subjected to post-stage color processing
The 8-bit data of each color of c and Lm is output Γ processing unit 213.
After the output Γ is corrected by the one-dimensional LUT, the quantization processing unit 221 performs binarization processing. In the case of the present embodiment, the relationship between the amount of light ink ejected per unit area and the light ink intex pattern indicating the light dot arrangement is as shown in FIG. That is, the number of dots formed in a unit area is increased to 0 to 8 as the amount of light ink ejected is increased to 0 to 200%. Note that, in FIG. 24, the index pattern shown by 9 levels of 0 to 8 has 9 gradations when 0 to 8 dots are formed for 8 pixels (4 × 2) of FIG. 22B. Equivalent to.

FIG. 26 shows each gradation level (density level).
It is a figure which shows the relationship with the index pattern of dark and light dots. Each gradation level shown in FIG. 26 and FIG.
7 corresponds to each gradation level in the LUT of the present invention, and each gradation level is converted into the index pattern of FIG. 26 based on this LUT. As is clear from FIG. 26, for light ink, in the range of gradation levels (density levels) 0 to 160, the number of light dots formed in a predetermined unit area increases from 0 as the gradation level increases. Gradually increase to eight,
A range of gradation levels higher than the gradation level 160 at which the formation amount per unit area reaches the first maximum amount (8) (160 to
In 255), the number of light dots formed in a predetermined unit area is gradually reduced from 8 to 0 as the gradation level becomes higher. For dark ink, the number of dark inks is increased from the gradation level after the gradation level 160 corresponding to the first maximum amount where the formation amount of the light ink is maximum, and the range of gradation levels (160 to 255)
In, the number of dark dots formed in a predetermined unit area is gradually increased from 0 to 4. Thus, the L of the present invention
When each gradation level is converted into an index pattern based on UT, the maximum number (8) of light dots formed in a predetermined unit area is the same as the number of dark dots formed in a predetermined unit area. It is twice the maximum number (4). Note that as is clear from FIG.
In the case of (4), the ejection amount is 100% when 4 dots are formed per unit area, and the ejection amount is 20% when 8 dots are formed per unit area.
It becomes 0%.

In the above, the amount of light ink shot is set to 2
Although the case where it is set to 00% has been described, the ejection amount of the light ink is not limited to 200%. 20 light ink
Even if 0% or more is used, the concentration will increase. Therefore, when the maximum ejection amount of light ink is set to 200% or more when the gradation level corresponding to the maximum ejection amount of light ink is the same as the gradation level at which ejection of dark ink is started, FIG. Since the density area (tone level width) B in which the dark ink is ejected is narrower, it is possible to further reduce the graininess. As described above, when the driving amount is 200% or more, the first maximum amount, which is the maximum formation amount of light dots per unit area, is smaller than the second maximum amount (100%), which is the maximum formation amount of dark dots per unit area. It will be more than double.

The light ink ejection amount may be 175% instead of 200%. That is, when the gradation level corresponding to the maximum light ink ejection amount and the gradation level at which dark ink ejection is started are the same, setting the maximum light ink ejection amount to 175% results in 200% Compared to the case, the density area (tone level width) B in which the dark ink is ejected shown in FIG. 17 becomes wider, but it is narrower than the density area (tone level width) B in the conventional LUT. Since the graininess can be sufficiently reduced, the maximum amount of light ink ejected may be at least 175% or more. In this way, when the driving amount is 175% or more, the first maximum amount, which is the maximum formation amount of light dots per unit area, is smaller than the second maximum amount (100%), which is the maximum formation amount of dark dots per unit area. 1.75 times or more.

As described above, according to this embodiment, as shown in FIG.
As shown in the LUT of FIG. 17 or for the light ink, as the density level increases, the formation amount of light dots is gradually increased to the first maximum amount (for example, 200%) and then gradually decreased. As described above, the formation amount of the light dots is determined. For the dark ink, the first
In a range of density levels higher than a predetermined density level (density level at which dark ink starts to be formed) equal to or lower than the density level corresponding to the maximum amount, as the density level becomes higher, the formation amount of dark dots is set to the first value. Maximum amount (20
The formation amount of dark dots is determined so as to gradually increase to the second maximum amount (100%) smaller than 0%. In this way, by determining the formation amount of the dark and light dots corresponding to each density level, the maximum formation amount of the light dots is increased and the density region formed by only the light ink dots is widened as compared with the conventional method. As a result, the density area in which the dark dots where the graininess is noticeable is formed is narrowed, and the graininess is reduced as a whole.

(Second Embodiment) As described above, FIG.
When the LUT of No. 6 is used, the input gradation level at the time when the dark ink is started is increased, and as a result, the medium density area after the dark ink is started, that is, the density area A in which the granular feeling is likely to be given. Can be narrowed, and the density area B where the dark ink is ejected can also be narrowed. on the other hand,
The upper limit of the maximum ink ejection amount is determined by the type of recording medium. Therefore, it is necessary to determine the input gradation level at the time of starting the ejection of the dark ink so as to reduce the graininess of the dots within the range of the maximum ejection amount. However, when the maximum ejection amount is increased to the upper limit value, when the secondary color or the tertiary color is expressed by the color mixture with other color ink, the image may be deteriorated due to the ink bleeding.

In this embodiment, in order to determine the input gradation level at the time when the dark ink is started to be ejected, an evaluation formula for digitizing the graininess is used. As the evaluation formula for quantifying the granularity, in addition to the evaluation formula using Granularity evaluation function, Dooly and Shaw using Wiener spectrum and VTF
Is known. In this case, Granular
An evaluation formula using the ity evaluation function was used. The evaluation formula evaluates graininess by using the Granularity evaluation function that incorporates human visual characteristics to the RMS graininess used as a measure for measuring graininess in silver halide photographic film. . Specifically, P ′ obtained by applying a visual filter to the image P, that is, an FFT (Fast Fourier Transform) spatial frequency component P ′ was obtained, and the standard deviation of the pixel values within the P ′ was taken as the granularity G. The observation distance in VTF (V) is assumed to be 28.6 cm. What is VTF (V)
It is a measurement of how many levels of brightness the human eye can discriminate for each spatial frequency (Dooly's approximation). The evaluation formula is shown below. The following formula is published in the document "High-quality inkjet printers and their evaluation" (Takeshi Makita, Atsushi Gota, Canon Inc.).

[0113]

[Equation 3]

I: pixel position in X direction j: pixel position in Y direction N: Size of image P in X and Y directions

Next, the correlation between the Granularity evaluation value (G) and the subject test was obtained. The printer used for the measurement is the Canon BJF-850 (6 color dark and light inkjet printer, resolution 1200dpi x 1200dpi, dot diameter 40μ.
m), the drum scanner is Howtek's ScanMaster 4500. In this measurement, the printer used a uniform density patch.
(Grayscale 50%) was output using K (black) ink, and the output image was read by a drum scanner having a resolution of 1000 dpi. The input image from the drum scanner was cut into 1024 x 1024 [pixels] and evaluated using the Granularity evaluation function. FIG. 25 shows the evaluation result.

From the Granularity evaluation value (G) of FIG. 25 and the result of the subject test, the evaluation value of the concentration area A in FIG.
It turns out that it needs to be kept below 0.6. More preferably, by controlling the content to be 0.4 or less, it is possible to reduce the graininess over the entire density region.

When determining the ink density, G
The ranularity evaluation function can be used as is.
For example, when determining the density of the light ink, the density of the light ink is diluted to ⅓, ¼, ⅕, ⅙ to determine whether dots are visible in the highlight area, In determining whether or not dark ink dots can be seen in,
Subjective evaluation and Granularity value are used together. This makes it possible to determine the density of the ink by comprehensively considering the graininess of the highlight portion and the medium density portion.

A granularity value is small over the entire density area by using the Granularity evaluation function (Granularity value 0.4 or less)
The ink density and dot diameter were examined so that As a result, in a 6-color dark / light inkjet printer like this example, the dot diameter is 30 μm (ejection amount 2 pl; bleeding rate is about 2.0), and the ink dilution ratio of the light ink is 1/3 of that of the dark ink. It was found that by using the above, the graininess can be reduced over the entire density region even when the maximum amount of light ink ejected is 100%.

In this embodiment, two types of ink having different densities are prepared only for cyan and magenta.
For yellow and black, it is also possible to use inks having different densities in combination. The ink is not limited to the combination of CMYK, and may be applied to other combinations, and it is also possible to use two kinds of inks having different densities for special colors such as gold and silver.

By the above image processing, high-definition image recording with little graininess can be performed over the entire density area.

(Other Embodiments) The recording head used in the present invention is not limited to an ink jet recording head for ejecting ink, but includes a plurality of various recording elements capable of forming dots on a recording medium. I wish I had it.

In the above embodiment, 600 dpi × 600.
Although it has been described that the gradation expression is performed for each unit area of dpi, the unit area (unit area) for which the gradation expression is performed is 600 dpi.
The area is not limited to i × 600 dpi. For example, gradation expression may be performed for each area of 1200 dpi × 1200 dpi, and the size of the unit area for gradation expression is. It is not limited to the numerical values in the above embodiment.

In the above description, for convenience, "600 dpi" is set.
The term “unit area (unit area) equivalent to a resolution of × 600 dpi” was used.
A unit area (unit area) corresponding to a resolution of 00 dpi is an area corresponding to (1/600) inch × (1/600) inch. Similarly, 1200 dpi × 1200 dpi
The unit area (unit area) corresponding to the resolution of i is (1 /
A unit area (unit area) corresponding to a resolution of 1200 dpi × 2400 dpi is (1/1200) inc.
It is an area equivalent to h × (1/2400) inch.

The object of the present invention is to supply a storage medium having a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to supply the computer (or CPU or MP
It goes without saying that U) 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 realizes the function 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, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD
-R, magnetic tape, non-volatile memory card, ROM, etc. can be used.

Moreover, not only the functions of the above-described embodiments are realized by executing the program code read by the computer, but also the OS (operating system) running on the computer based on the instructions of the program code. It is needless to say that this also includes a case where the above) performs a 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 in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that a case where the CPU or the like included in the function expansion board or the function expansion unit performs some or all of the actual processing and the processing realizes the functions of the above-described embodiments is also included.

(Others) The present invention is provided with a means (eg, electrothermal converter or laser beam) for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system. The present invention brings about excellent effects in a recording head and a recording apparatus of the type in which the state of ink is changed by the heat energy. This is because such a system can achieve high density recording and high definition recording.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal in a one-to-one correspondence
It is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the ink jet from the main body of the apparatus is electrically connected to the main body of the apparatus by mounting the recording head. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add ejection recovery means of the recording head, preliminary auxiliary means, etc. because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to control the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change of the ink from the solid state to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying thermal energy such as ink that is liquefied by applying thermal energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as a form of the ink jet recording apparatus of the present invention, in addition to the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function can be used. It may be a form or the like.

[0138]

As described above, according to the present invention, the maximum amount of light dots to be formed is increased so that the density region formed by only light ink dots is widened, and dark dots with a conspicuous graininess are formed. Since the formation amounts of the low-density dots and the high-density dots are optimally set so as to narrow the density region to be formed, it is possible to reduce the granularity of the dots over the entire density region.

[Brief description of drawings]

FIG. 1 is a perspective view showing an external configuration of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state where an exterior member of the printer shown in FIG. 1 is removed.

FIG. 3 is a perspective view showing an assembled state of the recording head cartridge used in the printer according to the embodiment of the invention.

FIG. 4 is an exploded perspective view showing the recording head cartridge shown in FIG.

5 is an exploded perspective view of the recording head shown in FIG. 4 as viewed from diagonally below.

6A and 6B are views showing the configuration of a scanner cartridge mountable on a printer according to an embodiment of the present invention in place of the recording head cartridge of FIG. 3, so that the scanner cartridge is turned upside down. FIG.

FIG. 7 is a block diagram schematically showing the overall configuration of an electric circuit in the printer of one embodiment of the present invention.

8 is a block diagram showing an internal configuration example of a main PCB in the electric circuit shown in FIG. 7. FIG.

9 is a block diagram showing an example of the internal configuration of an ASIC of the main PCB shown in FIG.

FIG. 10 is a flowchart illustrating an operation example of the printer according to the exemplary embodiment of the present invention.

FIG. 11 is a schematic configuration diagram of the recording head used in the first embodiment, which is a characteristic component of the present invention, as viewed from the nozzle side.

12 is an explanatory diagram when a plurality of recording heads in FIG. 11 is used.

13 is an enlarged cross-sectional view taken along the line XIII-XIII in FIG.

FIG. 14 is an explanatory diagram of the relationship between the impact amount of dark ink and light ink and the reflection density.

FIG. 15 is a conventional gradation level (density level)
FIG. 6 is a diagram showing a relationship between a dark ink and a light ink ejection amount.

FIG. 16 is a diagram showing the relationship between each gradation level (density level) and the amount of dark ink and light ink ejected in the first embodiment of the characteristic component part of the present invention.

FIG. 17 is an explanatory diagram of a specific comparative example of the conventional LUT and the LUT used in the present invention.

FIG. 18 is an explanatory diagram of a contrast difference between dark and light inks in FIGS. 15 and 16;

FIG. 19 is an explanatory diagram of a relationship between pixels and dots.

FIG. 20 is an explanatory diagram of a relationship between a dot area and a unit pixel area.

FIG. 21 is an explanatory diagram of a relationship between resolution and (dot area / unit pixel area).

22A and 22B are explanatory diagrams of the relationship between pixels and dots at different resolutions.

[Fig. 23] Fig. 23 is a block configuration diagram of an image data processing portion in the first embodiment of the characteristic configuration portion of the present invention.

FIG. 24 is an explanatory diagram of a light ink index pattern used in the image data processing portion of FIG. 23.

FIG. 25 is an explanatory diagram of the correlation between the value of the evaluation function of granularity and the subjective evaluation.

FIG. 26 is a diagram showing a relationship between each gradation level (density level) and an index pattern of dark and light dots.

[Explanation of symbols]

M1000 Main unit M1001 Lower case M1002 Upper case M1003 Access cover M1004 Ejection tray M2015 Paper interval adjusting lever M2003 Ejection roller M3001 LF roller M3019 Chassis M3022 Automatic feeding section M3029 Conveying section M3030 Discharging section M4000 Recording section M4001 Carriage M4002 Carriage cover M4007 Head Set lever M4021 Carriage shaft M5000 Recovery system unit M6000 Scanner M6001 Scanner holder M6003 Scanner cover M6004 Scanner contact PCB M6005 Scanner illumination lens M6006 Scanner reading lens 1 M6100 Storage box M6101 Storage box base M6102 Storage box cover M6103 Storage box cap M6104 Storage box spring E0001 Cat Edge motor E0002 LF motor E0003 PG motor E0004 Encoder sensor E0005 Encoder scale E0006 Ink end sensor E0007 PE sensor E0008 GAP sensor (paper gap sensor) E0009 ASF sensor E0010 PG sensor E0011 Contact FPC (flexible flexible cable) E0012 CRFFC (flexible flat cable) Carriage board E0014 Main board E0015 Power supply unit E0016 Parallel I / F E0017 Serial I / F E0018 Power supply key E0019 Resume key E0020 LED E0021 Buzzer E0022 Cover sensor E1001 CPU E1002 OSC (oscillator with built-in CPU) E1003 A / D (Built-in CPU) / D converter) E1004 ROM E1005 Oscillation circuit E1006 ASIC E1007 Reset circuit E1008 CR motor driver E1009 LF / PG motor driver E1010 Power supply control circuit E1011 INKS (ink end detection signal) E1012 TH (thermistor temperature detection signal) E1013 HSENS (head detection signal) ) E1014 control bus E1015 RESET (reset signal) E1016 RESUME (resume key input) E1017 POWER (power key input) E1018 BUZ (buzzer signal) E1019 oscillation circuit output signal E1020 ENC (encoder signal) E1021 head control signal E1022 VHON head ON signal) E1023 VMON (motor power ON signal) E1024 power control signal E1025 PES (PE detection signal) E1026 ASFS (ASF detection signal) E1027 GAPS (GAP detection signal) E0028 Serial I / F signal E1029 Serial I / F cable E1030 Parallel I / F signal E1031 Parallel I / F cable E1032 PGS (PG detection) Signal) E1033 PM control signal (pulse motor control signal) E1034 PG motor drive signal E1035 LF motor drive signal E1036 CR motor control signal E1037 CR motor drive signal E0038 LED drive signal E1039 VH (head power supply) E1040 VM (motor power supply) E1041 VDD (Logic power supply) E1042 COVS (cover detection signal) E2001 CPU I / F E2002 PLL E2003 DMA control unit E2004 DRAM control Part E2005 DRAM E2006 1284 I / F E2007 USB I / F E2008 Reception control unit E2009 Compression / expansion DMA E2010 Receive buffer E2011 Work buffer E2012 Work area DMA E2013 Record buffer transfer DMA E2014 Print buffer E2015 Record data expansion DMA E2016 Expansion data buffer E2017 column buffer E2018 head control unit E2019 encoder signal processing unit E2020 CR motor control unit E2021 LF / PG motor control unit E2022 sensor signal processing unit E2020 motor control buffer E2024 scanner acquisition buffer E2025 scanner data processing DMA E2026 scanner data buffer E2027 scanner data compression DMA E2028 sending bag FA E2029 Port control unit E2030 LED control unit E2031 CLK (clock signal) E2032 PDWM (software control signal) E2033 PLLON (PLL control signal) E2034 INT (interrupt signal) E2036 PIF reception data E2037 USB reception data E2038 WDIF (reception data / raster) Data) E2039 Receive buffer control unit E2040 RDWK (receive buffer read data /
Raster data) E2041 WDWK (Work buffer write data /
Recording code) E2042 WDWF (work fill data) E2043 RDWP (work buffer read data / recording code) E2044 WDWP (sorting recording code) E2045 RDHDG (recording development data) E2047 WDHDG (column buffer writing data / expansion recording data) E2048 RDHD (column buffer read data / developed recording data) E2049 Head drive timing signal E2050 Data developed timing signal E2051 RDPM (pulse motor drive table read data) E2052 Sensor detection signal E2053 WDHD (captured data) E2054 RDAV (capture buffer read data) E2055 WDAV (data buffer write data /
Processed data) E2056 RDYC (data buffer read data / processed data) E2057 WDYC (send buffer write data / compressed data) E2058 RDUSB (USB send data / compressed data) E2059 RDPIF (1284 send data) H1000 recording head cartridge H1001 recording Head H1100 Recording element substrate H1100T Ejection port H1200 First plate H1201 Ink supply port H1300 Electric wiring substrate H1301 External signal input terminal H1400 Second plate H1500 Tank holder H1501 Ink flow passage H1600 Flow passage forming member H1700 Filter H1800 Seal rubber H1900 Ink tank H1600d communication passage

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuji Konno             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Miyuki Fujita             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tetsuya Eedura             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tetsuhiro Maeda             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hiroshi Taka             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Mitsuhiko Masuyama             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2C056 EA04 EC69 EC74 ED03 ED05                       ED07 FA03 FA10 FA11 HA05                       HA22

Claims (33)

[Claims] 1. A determination means for determining the formation amount of low density dots and high density dots per unit area of the recording medium according to the density level of input image data for recording an image on the recording medium. In the image processing apparatus, the determining unit gradually increases the formation amount of the low-density dots to a first maximum amount and then gradually decreases as the density level increases, and In a range of a density level higher than a predetermined density level when a predetermined amount of dots are formed, as the density level increases, the formation amount of the high density dot is smaller than the first maximum amount. 2. An image processing apparatus, characterized in that the formation amounts of low-density dots and high-density dots corresponding to the density level are determined by gradually increasing the maximum amount. 2. The image processing apparatus according to claim 1, wherein the predetermined density level at which the high density dots are started to be formed is lower than a density level corresponding to the first maximum amount. 3. The formation amount of the low-density dots at the predetermined density level at which the high-density dots start to be formed is
The image processing apparatus according to claim 1 or 2, wherein the amount is at least twice the second maximum amount. 4. The formation amount of the low-density dots at the predetermined density level at which the high-density dots start to be formed is
The image processing device according to claim 1, wherein the image processing amount is 1.75 times or more of the second maximum amount. 5. The first maximum amount, which is the maximum formation amount of the low-density dots with respect to the unit area, is 1.75 with respect to the second maximum amount, which is the maximum formation amount of the high-density dots with respect to the unit area. The image processing device according to claim 1 or 2, wherein the number is doubled or more. 6. The first maximum amount, which is the maximum formation amount of the low-density dots per unit area, is twice or more the second maximum amount, which is the maximum formation amount of the high-density dots per unit area. The image processing device according to claim 1 or 2, wherein 7. The determining means determines the number of the low-density dots and the number of the high-density dots to be formed for the unit area, according to the density level. The image processing device according to 1 or 2. 8. The number of the low-density dots formed in the unit area in the case of the density level corresponding to the first maximum amount is the unit in the case of the density level corresponding to the second maximum amount. The image processing apparatus according to claim 7, wherein the number is equal to or more than 1.75 times the number of the high-density dots formed with respect to the area. 9. The density level at which the granularity G in the Granularity evaluation function is 0.6 or less is set as the predetermined density level at which the high-density dots start to be formed, and the Granularity evaluation function allows the image P to be visually recognized. The image processing apparatus according to claim 1, wherein a standard deviation of pixel values in the filtered image P ′ is represented as a granularity G by the following expression. [Equation 1] i: pixel position in X direction j: pixel position in Y direction N: size of image P in X and Y directions 10. The density level at which the granularity G in the Granularity evaluation function is 0.4 or less is set as the predetermined density level at which formation of the high-density dots is started. The image processing device described. 11. The low-density dots are ink dots formed by landing a light ink having a relatively low dye density on the recording medium, and the high-density dots are relative to each other. The image processing apparatus according to claim 1, wherein the ink dots are formed by landing a dark ink having a relatively high dye density on the recording medium. 12. An image processing method for determining the formation amount of low-density dots and high-density dots per unit area of the recording medium according to the density level of input image data for recording an image on the recording medium. When the density level is increased, the formation amount of the low-density dots is gradually increased to the first maximum amount and then gradually decreased, and the low-density dots are formed in a predetermined amount. In the range of the density level higher than the predetermined density level, the formation amount of the high-density dots is gradually increased to the second maximum amount smaller than the first maximum amount as the density level becomes higher. And then
An image processing method, characterized in that a formation amount of low-density dots and high-density dots corresponding to the density level is determined. 13. The image processing method according to claim 12, wherein the predetermined density level at which the high density dots are started to be formed is lower than a density level corresponding to the first maximum amount. 14. The method according to claim 12, wherein the formation amount of the low-density dots at the predetermined density level at which the high-density dots start to be formed is twice the second maximum amount or more. The described image processing method. 15. The formation amount of the low-density dots at the predetermined density level at which the high-density dots are started to be formed is 1.75 times or more of the second maximum amount. 13. The image processing method according to item 13. 16. The first maximum amount, which is the maximum formation amount of the low-density dots with respect to the unit area, is 1.75 with respect to the second maximum amount, which is the maximum formation amount of the high-density dots with respect to the unit area. The image processing method according to claim 12 or 13, characterized in that the number is twice or more. 17. The first maximum amount, which is the maximum formation amount of the low-density dots per unit area, is twice or more the second maximum amount, which is the maximum formation amount of the high-density dots per unit area. The method according to claim 1, wherein
The image processing method according to 2 or 13. 18. The number of the low-density dots and the number of the high-density dots to be formed in the unit area are determined according to the density level.
Alternatively, the image processing method described in 13 above. 19. The number of the low-density dots formed in the unit area in the case of the density level corresponding to the first maximum amount is the unit in the case of the density level corresponding to the second maximum amount. 2. The number is 1.75 times or more the number of the high density dots formed with respect to the area.
8. The image processing method according to item 8. 20. The density level at which the granularity G in the Granularity evaluation function is 0.6 or less is set as the predetermined density level at which formation of the high-density dot is started, and the Granularity evaluation function visually determines the image P. 13. The standard deviation of pixel values in the filtered image P ′ is defined as the granularity G and is expressed by the following equation.
The image processing method described in. [Equation 2] i: pixel position in X direction j: pixel position in Y direction N: size of image P in X and Y directions 21. The density level at which the granularity G in the Granularity evaluation function is 0.4 or less is set as the predetermined density level at which formation of the high-density dot is started. The described image processing method. 22. The low density dots are ink dots formed by landing a light ink having a relatively low dye density on the recording medium, and the high density dots are relative to each other. 13. An ink dot formed by landing a dark ink having a relatively high dye density on the recording medium.
The image processing method described in. 23. An image processing unit for executing the image processing method according to claim 12, and a formation amount of low-density dots and high-density dots determined by the image processing unit. And a recording unit for forming the low-density dots and the high-density dots on a recording medium based on the recording medium. 24. The recording section is an ink jet recording head capable of ejecting a light ink for forming the low density dots and a dark ink for forming the high density dots. 23. The recording device according to 23. 25. The recording apparatus according to claim 24, wherein the inkjet recording head has an electrothermal converter that generates thermal energy used to eject the light ink and the dark ink. . 26. An image processing step for executing the image processing method according to claim 12, and based on an amount of low density dots and high density dots formed in the image processing step. And a dot forming step of forming the low-density dots and the high-density dots on the recording medium. 27. The recording section is an inkjet recording head capable of ejecting a light ink for forming the low density dots and a dark ink for forming the high density dots. The recording method according to 26. 28. The recording method according to claim 27, wherein the inkjet recording head has an electrothermal converter that generates thermal energy used to eject the light ink and the dark ink. . 29. A control program for controlling a recording device for recording an image on a recording medium by using a recording unit for forming low-density dots and high-density dots on the recording medium, the control program comprising: According to the density level of the input image data for recording an image on the recording medium, when determining the formation amount of the low density dots and the high density dots per unit area of the recording medium, the density level becomes high. Therefore, the formation amount of the low-density dots is gradually increased to the first maximum amount and then gradually decreased, and the formation amount of the low-density dots is higher than the predetermined density level when the predetermined amount of the low-density dots is formed. In the range, the higher the concentration level,
The formation amount of the high-density dots is gradually increased to the second maximum amount, which is smaller than the first maximum amount, so that the low-density dots and the high-density dots corresponding to the density level per unit area. A control program that causes a computer to execute the step of determining the formation amount. 30. The control program according to claim 29, wherein the predetermined density level at which the formation of the high density dots is started is lower than a density level corresponding to the first maximum amount. 31. The formation amount of the low density dots at the predetermined density level at which the formation of the high density dots is started is at least twice the second maximum amount. The described control program. 32. The formation amount of the low-density dots at the predetermined density level at which the high-density dots start to be formed is 1.75 times or more the second maximum amount. 30. The control program according to item 30. 33. A storage medium storing a computer-readable program code, which stores the control program according to claim 29.