JP2000108324A - Ink jet recorder and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the quality of recorded image by performing the recording operation such that dots are imparted in the direction for increasing the density of a record data. SOLUTION: A logic control circuit 107 reads out an image data from an external memory 108 and converts it into a 2-bit data through an encoder 205. In this regard, three 2-bit data corresponding to dots being recorded are generated for one pixel and stored in an FIFO. It is outputted for each path and recorded by means of a head cartridge 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording method and apparatus for performing recording by discharging ink from a recording head onto a recording material.

[0002]

2. Description of the Related Art A recording apparatus such as a printer, a copying machine, a facsimile, etc., uses a recording element (a nozzle, a heating element, a wire, or the like) to form dots on a recording material such as paper or a plastic book board based on image information. , And an image composed of the dots is recorded. Such recording apparatuses can be classified into, for example, an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to the recording method. Among them, the ink jet type (ink jet printer) includes an ejection port (a nozzle ) To eject and fly ink (recording liquid) droplets,
This is attached to a recording material to record an image.

In recent years, a large number of recording devices have been used for output terminals and the like such as personal computers and image processing devices, and these recording devices require high-speed recording, high resolution, high image quality, low noise, and the like. Has been requested. The above-described ink jet recording apparatus can be cited as a recording apparatus that meets such requirements. In this ink jet recording apparatus, since recording is performed by discharging ink from the recording head, recording can be performed without contacting the recording material, and therefore, a very stable recorded image can be obtained.

In recent years, with the development of various digital cameras, digital videos, CD-ROMs and the like, pictorial image data can be easily handled on an application of a host computer. This allows
The printer, which is the output device, has been required to be capable of outputting pictorial images. Conventionally, such pictorial image output has been performed by a high-grade silver halide recording apparatus that inputs a digital image, or a sublimation recording apparatus that is limited to a photographic output using a sublimable dye. .

[0005]

In the above-mentioned conventional example, a recording apparatus dedicated to recording a photographic image or the like is very expensive. One reason is that the process is very complicated due to the use of the silver halide method, and the device is too large to be a desktop. Also, as is well known, even a type using a sublimation dye is very expensive in terms of both the cost of the main body and the running cost in proportion to the size of the recording medium, and can be used very easily for personal use. Was not. Also,
The greatest drawback of these recording devices is that they are designed on the premise of special recording media. In other words, since usable recording media are limited, in a personal process environment or general business use, ordinary paper is usually used to record documents and graphics, and photographic images are printed using special paper. It was extremely cumbersome to use and perform pictorially, and the operability was poor.

[0006] An ink jet printer is known as a recording apparatus in which the limitation on the recording material is reduced. In order to solve these problems, such an ink jet printer is required to improve image processing, use a colorant, and so on. In recent years, photographic images have been significantly improved in image quality due to improvements in recording materials and the like.

Further, among these color outputs, various studies have been made to improve the gradation of the color graphic output. For example, by increasing the printing resolution by increasing the printing resolution relative to the normal color printing mode, increasing the printing resolution of the printing apparatus, sending multi-valued image data to the printing apparatus as print data, and using sub-pixels. Improvements such as multi-value output have been proposed, and practical use has been achieved in recent years.

Further, a method has been put to practical use in which the ink discharge amount of the recording head is switched and the discharge amount is uniformly reduced relatively uniformly in the high resolution mode. Further, a recording head or the like capable of arbitrarily modulating an ink ejection amount from each nozzle has been proposed.

However, the above-mentioned conventional method has the following problems.

In the method of uniformly reducing the ink ejection amount, the printing is performed with the resolution increased in each of the main scanning direction and the sub-scanning direction.
There is a drawback that the recording speed is greatly reduced by reducing the feed amount in the sub-scanning direction. Also, increasing the resolution of the recording data greatly increases the amount of data, and the memory capacity for storing the recording data increases significantly.
The data transfer amount and transfer time in the interface are increased, and the load on the printer driver is increased. For example, if the resolution of the recorded data is doubled,
Since the data amount is doubled in both the main scanning direction and the sub-scanning direction of the recording data, the data amount is increased by a factor of four for convenience. Furthermore, since the recording dots are miniaturized in order to reduce the graininess (roughness) in the low-density part, many fine dots are similarly printed even in a high-density part where the graininess is not conspicuous. , Resulting in an inefficient one for the improvement in image quality as a whole.

As another method, there is a method of recording by using a mixture of large-sized large dots and small-sized small dots. According to such a method, inefficiency in image formation can be eliminated. However, this method can be easily realized when the number of recording nozzles is one for each color. However, when the number of nozzles increases, the method becomes more difficult as the number of nozzles increases. In general, the ejection of ink droplets from each nozzle is performed at a frequency of several Khz or more, and can be directly controlled by the CPU as long as the number of nozzles is small. Must be used together. When the ink ejection amount is modulated using such large dots and small dots, the dot size is switched by modulating a drive pulse for ejection or by switching a drive element in a nozzle used for ejection. Done in

When the latter driving element is switched, it is necessary to prepare a register in the recording head for each of the large dot and the small dot. The required number of registers will be an integral multiple of the recorded resolution. In this case, the circuit scale of the recording head is increased, and the cost of the recording head is increased. Also, in the former method of modulating the drive pulse, individual signal lines are required to individually control each nozzle, and a single signal line is usually required for several hundreds (for the number of nozzles). As a result, the number of contacts, the connection cable to the print head, the semiconductor for the driver of the print element, and the like are also required, resulting in a significant increase in cost.

If giving up printing by mixing large dots and small dots in one scan of the print head, the print head is scanned a plurality of times, and printing is performed by combining scanning of large dots and scanning of small dots. Will be. According to this method, large dots and small dots can be mixed in an image with a simple configuration. However, this method always performs a plurality of printing scans (multi-pass printing). Now, for example, even if a small dot is recorded for most of the addresses in one scan, and only one large dot exists in one scan, a total of two times to record that one large dot. Must be performed. Further, in reality, the more the number of times of multi-pass printing is increased, the longer the recording time becomes. Therefore, the number of times of multi-pass printing needs to be minimized. In this case, it is assumed that a problem occurs when, for example, printing is performed in two passes and gradation printing is performed from low density (white) to high density (maximum density). When a color (including a gray scale) starts to appear starting from a low density, recording is performed from the smallest small dot. Then, as the density of the image increases, small dots are recorded on grid points (virtual recording dot positions) at which recording can be performed by the recording head. After all the small dots have been recorded in this manner, the small dots and the large dots are mixedly recorded on the image. Then, it is assumed that when the image density further increases, a larger dot is printed and reaches the maximum density.

Here, the recording control of the recording apparatus is such that recording by large dots and recording by small dots are switched for each recording scan. When printing is performed under such conditions, the above-mentioned small dots are all printed on printable grid points, and when there is no large dot, useless printing scanning without print dots is performed as described above. In addition to this problem, 100% of prints (small dots) are concentrated in one print scan of two print scans, which is a characteristic feature of the original multi-pass printing. The so-called banding effect such as uneven discharge amount and uneven paper feed amount cannot be obtained.
Furthermore, since the recording ratio between each recording scan is not uniform, the error rate of the scanning with a high recording ratio cannot be reduced, or the instantaneous power increases at the time of high ratio recording scanning,
There was a problem that power consumption could not be reduced.

The present invention has been made in view of the above conventional example, and has as its object to provide an ink jet recording method and apparatus capable of recording an image at different gradations according to recording data.

An object of the present invention is to provide a simple configuration by performing ejection amount modulation for performing ink ejection for forming dots having different diameters, and providing print data in accordance with ink ejection timing of a desired dot diameter. It is another object of the present invention to provide an ink jet recording method and an apparatus which enable modulation of a dot diameter within one recording scan.

Further, it is an object of the present invention to perform recording by adding dots when the density of print data increases (darkens), thereby eliminating gaps in the recorded image and improving image quality. It is an object of the present invention to provide an ink jet recording method and a device therefor which can improve the recording quality.

[0018]

In order to achieve the above object, an ink jet recording apparatus according to the present invention has the following arrangement. That is, an ink jet recording apparatus that performs recording on a recording medium by discharging ink from each of a plurality of recording elements of a recording head, and an ink discharge amount changing unit that varies ink discharge from each recording element of the recording head. Modulation means for modulating recording data so as to provide recording dots in a direction in which the density of the recording data increases, timing control means for determining ink ejection timing of the ink ejection amount changing means, and modulation by the modulation means. Control means for controlling the recording of an image on the recording medium by outputting the recorded recording data in synchronization with the ejection timing determined by the timing control means.

In order to achieve the above object, the ink jet recording method of the present invention comprises the following steps.
That is, this is an ink jet recording method in which recording is performed on a recording medium by discharging ink from each of a plurality of recording elements of a recording head, and the recording data is modulated so as to provide recording dots in a direction in which the density of the recording data increases. An image is recorded on the recording medium by outputting the recording data modulated in the modulation step and the modulation step in synchronization with the ink ejection timing of each recording element of the recording head that makes the ink ejection amount different from each other. And a control step.

[0020]

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

FIG. 1 is a diagram showing a print / printer according to an embodiment of the present invention.
FIG. 1 is a block diagram illustrating a configuration of a system.

In FIG. 1, the host computer has:
Generally, it is configured to process various data with application software 102 that runs on an OS 101 (operating system). A description will now be given of a data flow in a case where image data created using the application software 102 for handling pictorial images is output to a printer device via a printer driver 103 and printed out.

If the image data processed by the application software 102 is a pictorial image, a multi-valued R
The data is sent to the printer driver 103 as GB data.
The printer driver 103 performs color processing on multi-valued RGB data received from the application software 102,
Further, halftone processing is performed to convert the data into binary CMYK data. The image data converted in this way is output via an interface for a printer in the host computer or an interface to a storage device for a file. In FIG. 1, the output is performed via an interface to the printer device.

In the printer, the controller software 1
Under the control of step 04, the image data is received, the print mode, the consistency of the ink jet cartridge, etc. are checked, and the received image data is passed to the engine software 105. The engine software 105 receives the received image data as a print mode or data structure designated by the controller software 104, generates an ink ejection pulse based on the image data, and outputs the pulse to the head cartridge 106. Meanwhile, the controller software and the engine software record and reproduce necessary image data and processing procedures in the memory device 108 through the logic control circuit 107. Further, necessary image data is read from the memory through the logic control circuit 107, and is sequentially transferred to the head cartridge 106 while being converted into a required format by the logic control circuit 107. Thus, the head cartridge 106 is configured to discharge ink of a corresponding color to record a color image on a recording material in accordance with the image data. Note that the cartridge 106 has an ink tank that stores ink of each color and a recording head that are integrally formed.

FIG. 2 is a diagram showing a mechanical configuration of a preferred ink-jet recording apparatus 200 of a cartridge exchange type according to an embodiment of the present invention, in which a front cover of the ink-jet recording apparatus is removed so that the inside of the apparatus configuration can be seen. Indicated by.

In FIG. 2, reference numeral 1 denotes a replaceable head cartridge (corresponding to 106 in FIG. 1). The cartridge 1 has an ink tank portion for storing ink and a recording head. Reference numeral 2 denotes a carriage unit, which performs recording by mounting the head cartridge 1 and moving in the left-right direction. Reference numeral 3 denotes a holder for fixing the head cartridge 1,
It operates in conjunction with the cartridge fixing lever 4. That is,
After the head cartridge 1 is mounted in the carriage unit 2, the head cartridge 1 is pressed against the carriage unit 2 by operating the cartridge fixing lever 4. Thus, the positioning of the head cartridge 1 and the electrical contact between the head cartridge 1 and the carriage unit 2 are obtained. Reference numeral 5 denotes a flexible cable for transmitting an electric signal to the carriage unit 2. A carriage motor 6 reciprocates the carriage unit 2 in the main scanning direction by its rotation. 7 is a carriage belt
Driven by the carriage motor 6 to move,
The carriage unit 2 is moved in the left-right direction. 8
Is a guide shaft for instructing the carriage unit 2 to be slidable. Reference numeral 9 denotes a home position sensor having a photocoupler for determining the home position of the carriage unit 2. Reference numeral 10 denotes a light shielding plate for detecting the home position. When the carriage unit 2 reaches the home position, the carriage unit 2 reaches the home position by shielding the photocoupler provided on the carriage unit 2 from light. Is detected.
A home position unit 12 includes a recovery mechanism for the recording head of the head cartridge 1 and the like. Reference numeral 13 denotes a discharge roller for discharging the recording medium. The discharge roller 13 sandwiches the recording medium with a spur unit (not shown) and discharges the recording medium out of the recording apparatus. An LF unit 14 conveys the recording medium by a predetermined amount in the sub-scanning direction.

FIG. 3 is a detailed view of the head cartridge 1 used in the embodiment of the present invention.

In the figure, reference numeral 15 denotes a replaceable black (Bk) ink tank. Reference numeral 16 denotes a replaceable ink tank which stores inks of C, M, and Y colorants. 1
A connection port (color material supply port) 7 of the ink tank 16 is connected to the head cartridge 1 and supplies a color material. 18
Denotes a connection port (color material supply port) of the ink tank 15. The color material supply ports 17 and 18 are connected to a supply pipe 20 and configured to supply a color material to the recording head unit 21. 19
Is a contact portion of an electric signal, which is connected to the flexible cable 5 (FIG. 2) so as to transmit various signals to the head cartridge 1.

FIG. 4 is a detailed view of the contact portion 19 of the head cartridge 1.

The contact portion 19 is provided with a plurality of electrode pads. Through the electric pads of the contact portion 19, signals relating to ink ejection, ID signals for recognizing the head cartridge 1, and the like are recorded by ink jet recording. It is connected and exchanged with the device main body.

Further, it is possible to detect whether or not the head cartridge 1 is mounted by checking the conduction state via the contact portion 19 shown in FIG.

FIG. 5 shows a printer driver 1 according to this embodiment.
13 is a flowchart illustrating an example of image processing by an image processing module in 03.

First, in step S101, a luminance / density conversion is performed to convert the luminance signal of RGB into a density signal of 24 bits in total of 8 bits for each of CMY or 32 bits in total of YMCK. Next, in step S102, a masking process is performed, and a correction process for unnecessary color components of the dye in each of the CMY colorants is performed. Next, step S10
Proceeding to step 3, UCR / RGB processing is performed to remove the background color and extract the black component. Then, in step S104, the driving amounts for the primary color and the secondary color are limited to each pixel. Here, the primary color is 300% and the secondary color is 40
Limit to 0%.

Next, in step S105, output gamma correction is performed so that the output characteristics are linear. Up to this point, an 8-bit multi-value output for each color is performed. Next, in step S106, halftone processing is performed on the 8-bit signal to convert the data of each color of CMYK into a 1-bit or 2-bit signal. At this time, in step S106, halftone processing is performed using an error diffusion method, a dither method, or the like.

FIG. 6 is a diagram showing the flow of signals inside the head cartridge of the printer of this embodiment.
Here, in particular, two ink ejection heaters are provided for one nozzle, and each heater has a different heat value. A case will be described in which the size of the ejected ink droplet (the size of the printed dot) is changed by switching the heater to be driven and printing is performed.

In FIG. 6, reference numeral 601 denotes a heater board of a recording head. Image data 621 to be recorded on the heater board 601 is transmitted serially from the printer in synchronization with a clock signal 622. This serial data is transferred to and held in the shift register 602. When all the serial data to be recorded at one timing is transferred to the shift register 602, a latch signal 623 is output from the recording apparatus main body, and the data held in the shift register 602 is synchronized with the latch signal 623. Are latched by the latch circuit 603. Next, the image data recorded in the latch circuit 603 is subjected to grouping designated so that dots are discretely present by various methods. Then, according to the block selection signal 624, the output of the latch circuit 603 is selected and output to each heater driver.
Reference numeral 605 denotes an odd / even selection circuit (Odd / Even Selector).
According to the selection signal 625, whether to drive the odd-numbered nozzles or the even-numbered nozzles of the recording head is selected. At this time, as an example of the circuit configuration of the recording head used in the embodiment of the present invention, two ejection heaters A and B for large dots and small dots are arranged corresponding to one nozzle. When the ink discharge amount is switched, the heater to be used is switched and modulated. In addition,
In another embodiment, a plurality of heating resistors are provided in one nozzle, and the amount of heat energy generated by changing the number of the heating resistors is changed to change the ink ejection amount. Is also good.

In this embodiment, the shift register 602 and the latch circuit 603 have the same number of bits as the number of nozzles. Shift the corresponding data to shift register 6
02 and the latch circuit 603, and the data corresponding to the large dots and small dots recorded in the second cycle are held in the shift register 602 and the latch circuit 603. Although printing is performed for columns, the shift register 602 and the latch circuit 603 may each be capable of holding a bit number that is twice the number of nozzles (when one pixel is composed of two bits).

It should be noted that various methods can be considered as a method of controlling the size of a dot to be printed based on the above configuration. Here, for example, when considering the nozzle 1, a heat enable signal (HEA) is considered. When the ejection heater A 607 is driven via the driver A 606 by the driver 627, the amount of ink ejected from the nozzle 1 increases to form a large dot, and the heat enable signal (HEB)
When the ejection heater 609 is driven via the driver B 608 by the driver 626, a small amount of ink is ejected from the nozzle 1 to form small dots. Similarly, when the ejection heater 611 is driven by the driver A 610, large dots are formed, and when the ejection heater 613 is driven by the driver B 612, small dots are formed.

In the above arrangement, the conditions for recording dots at designated positions on the recording material are as follows.

(1) The corresponding bit of each print data corresponding to each ejection nozzle latched by the latch circuit 603 is "1" (data is present).

(2) The block corresponds to the block selected by the block selection signal 624.

(3) The odd nozzle / even nozzle selection signal 625 corresponds to the nozzle position.

(4) Corresponding heat enable signal 6
26, 627 are input.

When the above four conditions are simultaneously satisfied, one of the ejection heaters A and B of the corresponding nozzle is driven, and a large dot or a small dot is output from the nozzle. That is, the dot diameter of the ink droplet ejected from the nozzle is determined depending on whether the heat enable signal input at that time is the signal 626 or the signal 627, and the print data is set to the high level (“ 1 ") determines where large and small dots are located.

Next, a specific printing example will be described with reference to FIGS. Here, in order to simplify the explanation, it is assumed that the recording head has only one nozzle. In these figures, grids indicated as grids indicate dot positions recorded by the recording head.

In FIG. 7, the grid spacing in the main scanning direction is 720 dpi (dots / inch). This nozzle 1 is the nozzle of block 1 here. Here, since there is only one nozzle, a selection signal 624 for selecting block 1 and a signal 6 for selecting odd-numbered nozzles
25 is turned on (high level) every time. Further, a portion indicated by “H” in the data indicated by the image data indicates that the recording data exists, and “L” indicates that there is no data. In the heat enable signal, “A” indicates that the ejection signal (large dot) is sent to the driver A, and “B” indicates that the ejection heat signal (small dot) is sent to the driver B.

As a result, as shown in FIG. 7, large dots and small dots are mixedly recorded in the same recording scan.
That is, when the heat enable signals A and B are output, the large dots 70 and 73 and the small dots 7
1,72 are recorded.

If only large dots are required, FIG.
When the image data corresponding to the nozzle is at the high level (H), the heat enable signal 627 may be output as shown in FIG.

Conversely, if only small dots are required, a heat enable signal 626 may be output when the image data corresponding to the nozzle is at a high level (H), as shown in FIG.

Next, a case where recording is performed by using a plurality of nozzles using a recording head having a plurality of noises will be described. When a plurality of nozzles are used, a plurality of block selection signals are required as compared with the case of one nozzle. Although there are several driving methods here, an example is shown in which a set selected by an odd signal and an even signal for adjacent nozzles is one block, and nozzle numbers are arranged in ascending order.

As shown in FIG. 10, in a print head having 16 nozzles, the number of blocks is "8". Here, the nozzle indicated by nozzle 1 and the adjacent nozzle (nozzle 2) are referred to as block 1, and the block numbers are sequentially increased to 2, 3, and 4 as the nozzle number increases. In the example of FIG. 10, block 1 (B1) to block 8 (B
8). In this state, nozzles satisfying the conditions of the image data at the high level (1), the heat enable signal on, the block selection signal, and the odd / even selection signal are driven to eject ink.

FIG. 10 shows all the nozzles 1 in one scan.
16 shows a case where ink is ejected from # 16 to dot printing.

First, when four signals of the image data, the heat enable, the block selection signal (B1), and the odd / even selection signal (odd) overlap with the nozzle 1 at the timing 80, the heat enable signal is changed to "A". Therefore, a driving signal is sent to the driver A connected to the discharge heater A in the nozzle 1, and a large dot is formed from the nozzle 1. At the next timing 81, the image data, the heat enable, the block selection signal (B5), and the odd / even selection signal (odd number) are given to the nozzle 9 of the block 5 (because the head is tilted).
When the four signals overlap, the heat enable signal is "B", so that a drive signal is sent to the driver B connected to the ejection heater B in the nozzle 1 and Dots are formed.

Next, the same processing is performed for the nozzle 2 of the block 1 and the nozzle 10 of the block 5, the driving up to the last nozzle 16 of the block 8 is completed, and recording of one cycle of a large dot, When one cycle of recording is completed, a total of 2
The recording for the cycle is completed.

FIG. 11 shows an image on which recording has been completed.

In FIG. 11, 720 dpi × 360 dpi
3 shows the arrangement of dots on the recording material when recording is performed in such a manner that the ejection timing of each nozzle is adjusted to an address corresponding to the resolution of. Note that FIG. 11 shows a state in which the large dot is recorded for two cycles and the small dot is recorded for two cycles in the print data “11” of all nozzles.

An application in an actual printer system will be described using such a system that can print large and small dots.

FIG. 12 shows a state where the head 10 is controlled by the control unit of the printer.
6 is a diagram showing the flow of data sent to the same reference numerals, and parts common to the above-described drawings are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 200 denotes a CPU, which controls the operation of the entire printer of the embodiment. FIG. 12 shows a signal flow of only a portion related to the gist of the present embodiment. A RAM 201 includes a print buffer 210 storing print data, conversion data 211 storing conversion data for converting pixel data, an encoding table 212, and a work area 213. Each pixel of the print data stored in the print buffer 210 is composed of 2 bits, and the gate array (GA) 202 reads the print data stored in the print buffer 210 by direct memory access (DMA). Here, as a form of the embodiment, the functions of the gate array 202 include a data converter 204, an encoder 205, and the like. In particular, parts other than these parts will be expressed as a gate array here. Here, data is usually read from the print buffer 210 in multiples of 16 bits. For this reason, the data arranged in a thick frame is read out by the gate array 202 in the data arrangement shown in FIG. Reference numeral 204 denotes a data converter for converting plane element data in accordance with the conversion data. The data converter 204 divides data of the recording pass when performing multi-pass printing. A decoder 205 encodes (modulates) 2-bit print data in accordance with the data table (modulation data) stored in the encode table 212. Reference numeral 206 denotes a register of the gate array 202, which includes a register 206a for storing thick dot forming data and a register 206b for storing small dot forming data.

FIG. 13 shows a portion (only 32 nozzles) of a recording head having, for example, 256 nozzles, and this head is inclined by a predetermined angle θ with respect to the scanning direction of the head (right horizontal direction in FIG. 13). It is arranged.

In FIG. 13, in the first cycle, the large dots of the nozzles 1 and 17 and then the nozzles 9 and 25
The two nozzles are simultaneously driven to discharge ink, such as a small dot, a large dot of the nozzle 2 and the nozzle 18, and a small dot of the nozzle 10 and the nozzle 26 next. In the next second cycle, nozzle 1 and nozzle 17
Ink is simultaneously ejected from each of the two nozzles, such as a small dot, a large dot of the nozzle 9 and the nozzle 25, and then a small dot of the nozzle 2 and the nozzle 12, so that an image of a total of 32 pixels is recorded. You.

In the third period, the large dots of the nozzles 1 and 17, the small dots of the nozzles 9 and 25, and then the nozzles 2 and 18 are the same as in the first period.
Two large nozzles are simultaneously driven to perform printing, as in the case of a large dot. In the example of FIG. 13,
This is shown in the case where the print data is all “11”.

In this embodiment, in order to express gradation by combining two dots from 2-bit print data, the print data is stored in the print buffer 21.
0, the register 206 of the gate array 202
The data converter 204 and the encoder 2
05, the data is converted and stored. that time,
Several methods are conceivable for one-pass printing and multi-pass printing. First, an embodiment for one-pass printing will be described.

FIG. 14 is a diagram showing an example in which each plane element read from the print buffer 210 is encoded using the encoder 205 with print data represented by 2 bits.

The printer of this embodiment receives the quaternary data (each pixel is represented by 2 bits) output from the printer driver 103 of the host computer, and writes it into the print buffer 210.
Next, the 2-bit encoder 205 encodes the print data in accordance with the contents stored in the encode table 212 according to the correspondence shown in FIG. The data is DMA-transferred to the register 206 of 202. At this time, the print data passes through the data converter 204 as it is in the case of one-pass printing. In the example of FIG. 14, the 2-bit data "1"
Although an example is shown in which large dots and small dots are assigned to “0” and only small dots are assigned to print data “01”, by changing the contents of the encoding table 212, the encoder 205 converts the data into 2-bit data. On the other hand, any encoded output can be obtained.

Next, the case of the multi-pass printing method will be described. In the case of multi-pass printing, as shown in FIG. 15, 1 / n of the length of the nozzle row used (n = n in the example of FIG. 15).
In 3), the recording medium is fed in the sub-scanning direction for each recording scan by the recording head, and interpolation data is printed to complete an image.

In FIG. 15, 1/3 of each printing scan is performed.
The recording medium is fed by a height corresponding to the height of the nozzle of
This shows a state in which recording (for one band) is performed in a pass. In the conventional printing method, when printing of the thinned image is completed in the printing scans in various scanning directions, the image is printed in the sub-scanning direction, and the image of the portion thinned out in the previous main printing scan is printed. Complete the record. In this embodiment, 2-bit data is output for each main scan recording in the same manner as described above, and an encoding function is added to the conventional thinning function (here, data conversion) to further increase the width of gradation expression. It is a big one.

The function will be described with reference to FIG.

In the embodiment, the print data is 2
Since the gradation is expressed by bits, thinning-out (data conversion) data is created by combining two bits and stored in the conversion data area 211 of the RAM 201.
As a method of creating this data, as shown in FIG. 17, for example, when printing is performed by three passes in the memory area 211, three sets of 2-bit data (aa (for the first print pass), bb (For the second print pass) and cc (for the third print pass)) are assigned so as to be equal in number.

Next, the three sets of 2-bit data are exchangeably shuffled. By repeating this at least a certain number of times, a random number table in which three sets of data are replaced in a random manner is completed as shown by 170, 171, and 172 in FIG. The data created in this way is stored in the conversion data area 211 of FIG. In the case of printing in three passes, print data is converted by the data conversion circuit 204 for print data of each print scan in accordance with the conversion data. This example is shown in FIG.

In FIG. 16, reference numeral 160 denotes an example in which print data (2 bits) is converted by data "aa" and further converted by the encoder 205 in accordance with the contents of the encoding table 212. Reference numeral 161 denotes data "bb".
The print data is converted by the
05 shows an example in which the print data is converted in accordance with the contents of the encoding table 212, and 162 shows an example in which the print data is converted in accordance with the data "cc" and further converted by the encoder 205 in accordance with the contents of the encoding table 212. . As a result, reference numeral 163 indicates a print example of each surface element of the print data printed by three printing scans.

In the example of FIG. 16, the print data is “0”.
If the print data is “0” (xx and no print dot), the print data is “01”, indicating the minimum density, and only one small dot is printed by printing in three passes, and the print data is “10”. In the case, large dot and small dot are 1 each
When the print data is “11”, the large dot 2
Each piece is overprinted, and one small dot is recorded. FIG. 16 shows only one example, and the present invention is of course not limited to this example.

The encoding table 2 of the RAM 101
By changing the encoding contents of the twelve, it is possible to select, for example, any one of the four combinations of the output results shown in FIG. 16 from a plurality of combinations.

In this way, after recording with small dots, if the density further increases (increases) and large dots are recorded, as shown in the recording example of FIG. Dots and large dots appear in pairs at different recording positions. By utilizing this, it is possible to perform recording without causing a gap between adjacent small dots.

FIG. 19 shows a case where a large dot is arranged at a position indicated by 190 and a small dot is not recorded at an adjacent position at 191. In this case, a gap is generated on the right side of the large dot. Become.

Therefore, in the present embodiment, when the gradation is expressed by using the sub-pixels (two large and small dots), when the 2-bit input in FIG. 16 changes from “10” to “10”, By recording one large dot and one small dot, the occurrence of gaps in the image due to one missing small dot is suppressed.

FIG. 20 shows that 2-bit data is "1"
FIG. 9 is a diagram showing a problem that occurs when recording is performed with one large dot when the recording is “0”. Data “10” is recorded between images with print data “01”, and the image density changes. This shows an example in which a gap has occurred in a portion of the print data according to the embodiment of the present embodiment in which, when the print data is "10", one large dot and one small dot are recorded and eliminated. 21.

Similarly, FIG. 22 shows an example of printing in a boundary region between a high-density portion and a low-density portion, and this portion is processed in the same manner as in FIG. There is a gap. FIG. 23 shows an example in which this is solved.

By performing printing with such a bit configuration, two-bit data is uniformly distributed in a random manner for each printing scan, so that the difference in the number of printing dots between each printing scan is almost eliminated. It can be eliminated.

Further, in this embodiment, the use of the 2-bit code encoding table allows the distribution of large and small dots to be incorporated into the 2-bit set and shuffled. For this reason, even when the numbers of large dots and small dots are extremely deviated, it is possible to equally distribute each dot size for each print scan. If this function is effectively used, the conventional dynamic range is 2 bits, the maximum is 2 dots, and the number of gradations is 3 gradations.
A head capable of recording large and small dots in the present embodiment,
By using multi-pass printing, encoding using 2-bit code, random conversion data, etc., it is possible to perform printing combining up to three large dots and three small dots at the maximum. As a combination, four out of 16 gradations can be freely selected. Further, by increasing the number of passes in multi-pass printing or increasing the number of 2-bit codes to 3 bits or 4 bits, it is possible to dramatically increase the gradation expression capability and increase the dynamic range. . Further, the number of gradations may be not limited to two, but may be a plurality of gradation modulations.

FIG. 24 is a flowchart showing a printing process in the ink jet printer according to the present embodiment.
This process is executed under the control of the CPU 200. This process starts when data from the host computer is received and print data for at least one scan or one page is stored in the print buffer 210.

First, in step S1, the drive of the carriage motor 6 is started to start the movement of the head cartridge 106. In step S2, it is checked whether or not the print timing by the head has come. When the print timing comes, the process proceeds to step S3, in which printing is performed for one column of nozzles of the head by driving the head (flow chart in FIG. 25), and in step S4, it is determined whether the printing process for one row has been completed. If the printing process for one line has not been completed, the process returns to step S2. However, if the printing process for one line has been completed, the process proceeds to step S5, in which carriage return and conveyance of the recording paper for a length corresponding to the recording width are performed. Proceed to step S6. In step 6, it is checked whether printing of one page has been completed. If the printing has not been completed, the process returns to step S1, and if completed, the process proceeds to step S7 to discharge the recorded paper.

Next, the head driving process in the ink jet printer according to the present embodiment will be described with reference to the flowchart of FIG.

First, in step S11, print data for one row of nozzles of the head is read from the print buffer 210, and the data is passed through the data converter 204 and encoded by the encoder 205.
02 are set in the registers 206a and 206b (this part is performed by DMA). These registers 206a,
The data set in 206 b is transferred to the shift register 602 of the head 106. In this embodiment, since each nozzle forms one gradation dot (up to two dots) by driving the heaters A and B, first, the driving timing of the heater A is determined in step S14. See if it has become. If so, the process proceeds to step S15, where the block select signal 624 and the even number
An odd signal 625 is output to determine which nozzles are driven simultaneously. Then, a signal 627 for driving the heater A is output. Thus, if the data corresponding to the selected nozzle is "1", a large dot is formed.

Then, the process proceeds to a step S16 to check whether it is the heater B drive timing, and if it is the heater B drive timing, the process proceeds to a step S17 to output the block select signal 624 and the odd / even signal 625, A nozzle for driving B is determined, and a heat signal 626 is output. Thus, if the data corresponding to the nozzle is "1", a small dot is formed by the nozzle.

The flow advances to step S18 to check whether or not all the nozzles of the head have been driven and printing has been performed. If so, the flow returns to the original processing. If not, the flow advances to step S14, and the flow advances to step S14. The timing of the heater A and the timing of the heater B are checked, and printing is sequentially performed by other nozzles.

FIG. 26 is a flowchart showing a process for performing printing by three passes in this embodiment, and the same parts as those in the above-mentioned flowchart are omitted.

Here, in step S21, n = 3 is set, and in step S23, step n is performed until n = 0.
It can be easily realized by driving the head up to 2-S5 '. At this time, data to be recorded corresponding to each recording scan is created by the data converter 204 and the encoder 205 in FIG.

The present invention brings about an excellent effect in a recording head and a recording apparatus that use thermal energy among ink jet recording methods.

FIG. 27 is a diagram showing the logic control circuit 107 in the embodiment of the present invention in more detail. The numbers assigned to the blocks and having the same function are the same as those in the other drawings. Note that the description of blocks described in other drawings is omitted here.

First, in FIG. 27, the print buffer sequence controller 270 reads out the image data temporarily stored in the external memory 108 and adjusts the timing for sending the data downstream of the circuit.
The address generation circuit 271 is controlled by the print buffer sequence controller 270, and actually gives an address to the external memory 108. Address generation circuit 2
The function of 71 makes it possible to correctly read temporarily stored image data. The FIFO 272 includes three FIFO circuits, two types of selectors before and after the three FIFO circuits, and one FIFO controller. FIFO
Reference numeral 272 selectively distributes a signal from an upstream (described later) 2-bit encoder output to each FIFO and rearranges data. The DMA controller 273 is connected to the external memory 1
In the embodiment of the present invention, the image data is transferred from the internal transfer of the image data to the head cartridge 106 without prompting the controller / engine software. . In the embodiment of the present invention, the heat enable controller 274 enables printing of different dot diameters by sequentially sending enable signals to the head cartridge 106 at the time of image printing. However, the control of the dot diameter here corresponds only to the physical diameter, and the correspondence of the print data to the dot diameter can be achieved by synchronizing with the heat data.

Next, the data flow of the logic control circuit 107 will be briefly described. The data sent from the host computer (not shown) is stored in the external memory device 10 of the printer device.
8 is temporarily stored. The CPU 200 temporarily stores the data temporarily again in the external memory while converting the temporarily stored data into data that can be processed by the printer device. The data is read from the external memory device 108 by the logic control circuit 107, and two bits adjacent to each other are grouped into one group together with predetermined mask data (shown in the drawing) in the logic control circuit 107. 2 bits to2
The data is transferred to the bit encoder 205. This transfer is a DM
This is performed by the A controller 273. 2 bits to2
The bit encoder 205 includes an encoding table 212
, And transmits the transferred data to the FIFO 272 as 2-bit data that matches the table value. F
The data sent to the FIFO 272 is sent to the FIFO1, FIFO2a, FIFO
2b. The allocated 2-bit data is combined into an output by a selector at the subsequent stage of the FIFO. The combined 2-bit data is sent to the head cartridge 106 in phase with the enable signal of the heat enable controller 274.

Here, the input to the encoder 205 is shown in FIG.
6, the output data 160, 161, 162 are sequentially generated by the encoder 205, and the output data 160, 161, 162 are respectively stored in FIFO1, FIFO2a, FIFO2.
b. At this time, if the stored FIFOs are exchanged, shuffling can be performed as shown in FIG. This is performed in parallel for the number of nozzles of the head, and if the data stored in the FIFO 272 is output in the order of multi-pass printing passes, the ink jet printing apparatus of the present embodiment can be realized.

The present invention brings about an excellent effect particularly in a recording head and a recording apparatus using a thermal energy among the ink jet recording methods.

The typical structure and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an 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 transducer, and the film is heated on the heat-acting surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with the drive signal, which is effective. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble,
Form at least one drop. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. Examples of the drive signal in the form of a pulse include U.S. Pat. Nos. 4,463,359 and 4,345.
No. 262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

The configuration of the recording head is not limited to the combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned specifications. U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,558,333 which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 459600 is also included in the present invention. In addition, for multiple electrothermal transducers,
JP-A-59-123670 which discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter, and JP-A-Showa No. Sho-A1 which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy corresponds to a discharge portion The present invention is also effective as a configuration based on Japanese Patent Publication No. 138461/1984.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recordable recording medium described in the present embodiment, a multiple recording head as disclosed in the above-mentioned specification is used. Either a configuration that satisfies the length by combination or a configuration as a single recording head integrally formed may be used.

In addition, a replaceable chip type recording head which can be electrically connected to the apparatus main body and supplied with ink from the apparatus main body by being attached to the apparatus main body may be used. A cartridge type recording head in which an ink tank is provided integrally with the recording head itself may be used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like to the configuration of the printing apparatus described above, since the printing operation can be further stabilized. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof. It is also effective to provide a preliminary ejection mode for performing ejection that is different from printing, in order to perform stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be a single recording head or a combination of plural recording heads. Alternatively, the apparatus may be provided with at least one of full colors by color mixture.

In the embodiments described above, the description is made on the assumption that the ink is a liquid. However, even if the ink solidifies at room temperature or lower, it is possible to use an ink that softens or liquefies at room temperature. Or, in the ink jet method, generally, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range.
It is sufficient that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent the temperature rise due to thermal energy as energy for changing the state of the ink from the solid state to the liquid state, the temperature is positively prevented.
Alternatively, in order to prevent evaporation of the ink, an ink which solidifies in a standing state and liquefies by heating may be used. In any case, the application of heat energy causes the ink to be liquefied by application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held in a liquid state or a solid state in the concave portion or through hole of the porous sheet. It is good also as a form which opposes an electrothermal transducer. 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 to the above, the recording apparatus according to the present invention may be provided not only as an image output terminal of an information processing apparatus such as a computer but also integrally or separately, a copying apparatus combined with a reader, etc. It may take the form of a facsimile machine having functions.

[0104]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to provide a computer (or CPU) of the system or apparatus.
And MPU) read and execute the program code stored in the storage medium.

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

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

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

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the program code is read based on the instruction of the program code. It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

As described above, according to the present embodiment, it is possible to record a plurality of types of recording dots on a recording medium with a simple circuit configuration even in one scanning recording.

Further, even when the number of dots of each size becomes unbalanced when multi-pass printing is performed, the dots of each size can be dispersed substantially evenly during each main scan of printing.

Further, by dispersing the dots using a thinning mask for multi-pass printing, the selection and distribution of dots can be performed simultaneously.

Further, by performing operations such as dot selection and distribution and path management by a logic control circuit realized by a gate array, a small and inexpensive recording apparatus can be provided.

[0114]

As described above, according to the present invention, there is an effect that an image can be recorded with different gradations according to recording data.

Further, according to the present invention, the ejection amount is modulated so as to perform the ink ejection for forming dots having different diameters, and the recording data is provided in accordance with the ink ejection timing of the desired dot diameter, thereby achieving a simple configuration. In addition, there is an effect that it is possible to perform modulation with different dot diameters within one recording scan.

Further, according to the present invention, there is an effect that the quality of a recorded image can be improved by performing recording by adding dots when the density of recording data increases (darkens). .

Further, according to the present invention, the operations such as decoding of image data and distribution of data of each pass at the time of multi-pass printing are realized by the gate array, so that the configuration can be downsized.

[0118]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a printing system including a host computer and a printer according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating an overview of a recording unit of the printer device according to the embodiment of the present invention.

FIG. 3 is a perspective view illustrating a configuration of a head cartridge according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating an electrical connection between a head cartridge and a printer according to an embodiment of the present invention.

FIG. 5 is a flowchart illustrating processing of print data in a printer driver according to an embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a base circuit of the head cartridge according to the embodiment of the present invention.

FIG. 7 is a diagram illustrating formation of recording dots in the printer device according to the embodiment of the present invention.

FIG. 8 is a diagram showing an arrangement of recording dots in the recording apparatus of the present invention.

FIG. 9 is a diagram showing an arrangement of recording dots by the recording apparatus of the present invention.

FIG. 10 is a view showing an arrangement of recording dots by the recording apparatus of the present invention.

FIG. 11 is a diagram showing an arrangement of recording dots by the recording apparatus of the present invention.

FIG. 12 is a block diagram of a recording data processing circuit in the recording apparatus of the present invention.

FIG. 13 is a diagram showing dots of simultaneous ejection and areas of recording data to be transferred.

FIG. 14 is a diagram illustrating D / A conversion indicating data in a 2-bit encoding table.

FIG. 15 is a diagram illustrating a multi-pass printing method.

FIG. 16 is a diagram showing data in a 2-bit encoding table.

FIG. 17 is a diagram showing how to make a random mask.

FIG. 18 is a diagram illustrating a print example according to an embodiment of the present invention.

FIG. 19 is a diagram illustrating a problem caused by printing in a conventional example.

FIG. 20 is a diagram illustrating a problem caused by printing in a conventional example.

FIG. 21 is a diagram illustrating a print example according to an embodiment of the present invention.

FIG. 22 is a diagram illustrating a problem caused by a conventional printing method.

FIG. 23 is a diagram illustrating a print example according to an embodiment of the present invention.

FIG. 24 is a flowchart illustrating a printing process in the inkjet recording apparatus according to the embodiment of the present invention.

FIG. 25 is a flowchart showing a head driving process in step S3 of FIG. 24;

FIG. 26 is a flowchart illustrating printing in three passes according to an embodiment of the present invention.

FIG. 27 is a diagram illustrating details of a logic control circuit according to an embodiment of the present invention.

[Explanation of symbols]

 1, 106 Head cartridge 6 Carriage motor 101 Host computer 103 Printer driver 200 CPU 201 RAM 204 Data converter 205 Encoder 206 Register 602 Shift register 607, 611 Discharge heater register A 609, 619 Discharge heater register B

Claims (9)

[Claims] 1. An ink jet recording apparatus which performs recording on a recording medium by discharging ink from each of a plurality of recording elements of a recording head, wherein the amount of ink discharged from each recording element of the recording head is different. An amount changing unit, a modulation unit that modulates recording data so as to add recording dots in a direction in which the density of the recording data increases, a timing control unit that determines an ink ejection timing of the ink ejection changing unit, and the modulation unit. An ink jet recording apparatus comprising: control means for controlling the recording of the image on the recording medium by outputting the modulated recording data in synchronization with the ejection timing determined by the timing control means. . 2. The ink jet apparatus according to claim 1, wherein the timing control unit determines two types of ink ejection timings for recording at least a large dot from the recording element and recording a small dot from the recording element. Item 2. An ink jet recording apparatus according to item 1. 3. The method according to claim 1, wherein the ink discharge amount changing unit includes a heating resistor having a different heating value or a plurality of heating resistors for one recording element to drive the heating resistors. 3. The ink jet recording apparatus according to claim 1, wherein the ink ejection amount is changed by changing the number. 4. The ink-jet recording method according to claim 2, wherein the control means expresses the recording data modulated by the modulation means at least by combining small dots or a combination of large dots and small dots. apparatus. 5. A print scan data creating means for further changing the print data based on each print scan to create data corresponding to each print scan, and based on the print data created by the print scan data create means. The inkjet recording apparatus according to any one of claims 1 to 4, further comprising a multi-pass control unit that performs printing by a plurality of print scans. 6. The control means has means for converting one pixel into data of a predetermined number of digits corresponding to each pass of a multi-pass, and storing the data for each pass in a recording order. The inkjet recording apparatus according to claim 5. 7. An ink jet recording method for recording on a recording medium by discharging ink from each of a plurality of recording elements of a recording head, the recording data being provided so that recording dots are provided in a direction of increasing the density of the recording data. And a control step of recording an image on the recording medium by outputting the recording data modulated by the modulation unit in synchronization with the ejection timing determined by the timing control unit. An ink-jet recording method, characterized in that: 8. A print scan data creating step of further changing the print data based on each print scan to create data corresponding to each print scan, and a print scan data creating step based on the print data created by the print scan data creating step. 8. The inkjet printing method according to claim 7, further comprising a multi-pass control step of performing printing by a plurality of printing scans. 9. The control step according to claim 8, wherein one pixel is converted into data of a predetermined number of digits corresponding to each pass of a multi-pass, and stored for each pass in a recording order. 3. The inkjet recording method according to item 1.