JP2000326499A - Method and device for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alleviate the generation of a cockling phenomenon of a medium to be recorded by computing the printing rate on belt-shaped unit areas to be recorded based on an image data, selecting the printing mode based on the computed printing rate, utilizing the printing mode and recording on the unit areas. SOLUTION: A binary image data is received from an external computer terminal device or the like (S21), and the received data is analyzed by a CPU to provide a printing data for one band portion suitable for the recording by an ink jet (S22). The number of dots to be jetted based on the printing data is sensed (S23), and the printing rate is calculated based on the value of the number of dots and the number of dots to be jetted out in one band (S24). Also a printing mode to be adopted for one band is selected based on the printing rate (S25), and printing is carried out by driving respective heads based on the printing mode and the printing data (S26), and the printing is repeated until the completion of recording of all the bands (S27).

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 a single pass and a multi pass method.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, a recording head having a plurality of ejection ports (nozzles) for ejecting ink is repeatedly scanned in a direction different from the arrangement direction of the ejection ports to record an image. With the scanning, a partial image is formed in a band-shaped unit area (band). At this time, a so-called cockling phenomenon may occur in which the recording medium after ejection is deformed in a wave-like manner according to the amount of ink ejected from the ejection ports and the material of the recording medium.

It is known that such a cockling phenomenon can be prevented by adopting a multi-pass system in which the same band is divided into a plurality of scans and recorded.

[0004]

However, this multipath system has the following disadvantages.

[0005] The multi-pass method is a method in which one band is divided into a plurality of times for recording, and therefore requires a longer recording time than the single-pass method. For example, the two-pass method requires twice as long as the single-pass method and the five-pass method requires five times as much recording time.

In general, data transferred from a computer terminal connected to an ink jet recording apparatus includes vector data composed of line drawing information such as drawings designed by CAD, and image data composed of pictures and photographs. Data (bitmap data) exists. When image data is transferred, the amount of ink ejected inevitably increases, and the effect of preventing cockling by the multi-pass method is high. However, in the case of vector data with a small amount of ink ejected, cockling hardly occurs even in the single-pass system, but when the multi-pass system is adopted, only useless printing time is required, which is not efficient.

[0007] The present invention has been made in such a background, and by the processing on the ink jet recording apparatus side,
It is an object of the present invention to provide an ink jet recording method and apparatus capable of mitigating occurrence of a cockling phenomenon of a recording medium due to an amount of ink discharged from a discharge port and shortening an ink jet recording time as much as possible.

[0008]

In order to achieve the above object, an ink jet recording method according to the present invention is to repeatedly scan a recording head having a plurality of discharge ports for discharging ink in a direction different from the arrangement direction of the discharge ports. In the inkjet recording method of sequentially performing image recording for each band-shaped unit area, a printing rate of a band-shaped unit area of a recording target to be recorded by scanning of the recording head is calculated based on image data, and the calculated printing rate is calculated. A printing mode for the unit area is selected based on the printing rate, and recording of the unit area is performed in the selected printing mode.

The printing mode is selected from a single-pass system and a multi-pass system including at least a two-pass system.

For example, the occurrence of cockling can be suppressed by recording in a printing mode requiring a recording time, such as a multi-pass method, in a band-shaped unit area having a high printing rate. Conversely, recording is performed in a printing mode with a short recording time, such as a single pass method, for a band-shaped unit area having a low printing rate. As a result, the total recording time for one page can be reduced as much as possible as compared with the case where the multi-pass method is employed uniformly.

[0011] The ink jet recording apparatus according to the present invention comprises:
In an ink jet recording apparatus which repeatedly scans a recording head in which a plurality of ejection ports for ejecting ink are arranged in a direction different from the arrangement direction of the ejection ports to sequentially record an image in each band-shaped unit area, the plurality of recording heads are A carriage mounted and scanned on the recording medium, a conveying unit for conveying the recording medium in a direction substantially orthogonal to the scanning direction of the carriage, and performing ink ejection of the plurality of recording heads based on image data. Printing means, and printing control means capable of changing a printing mode for each band-shaped unit area corresponding to the scanning of the carriage, the printing control means,
A printing rate of a band-shaped unit area to be recorded is calculated based on the image data, a printing mode for the unit area is selected based on the calculated printing rate, and the unit area is selected in the selected printing mode. The carriage, the transporting means, and the printing means are controlled so as to perform the recording.

In this device, a table for selecting the printing mode according to the calculated printing rate may be used.

[0013] Further, a correction means for correcting the calculated printing rate based on various factors may be provided. The various factors are, for example, the type of the recording medium, the temperature and the humidity of the environment, and the like.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an ink jet recording apparatus according to the present invention. In FIG. 1, reference numeral 11 denotes a CPU (print control means) for controlling the operation of the entire apparatus and analyzing received binary image data and received data, and 12 a work area of the CPU 11 and suitable for recording by an inkjet head. The RAM is used as a temporary storage area for print data for one band. 1
Reference numeral 3 denotes an RO in which data such as a program for driving an ink jet recording apparatus and a print mode table (described later) for selecting a print mode based on a print ratio is written.
M, which is read and executed by the CPU 11. 1
Reference numeral 4 denotes an interface unit for connecting to an external computer terminal device or the like, through which binary image data is transferred. Reference numeral 15 denotes an LCD display device that performs display for a machine interface. Reference numeral 16 denotes a key operation unit for selecting various settings of the ink jet recording apparatus, and performs setting of a recording medium at the time of printing. Reference numeral 17 denotes a printing unit (printing means) using an inkjet head, and 18 denotes a CP.
This is a system bus that connects U11 to other elements.

The printing section 17 has a carriage (not shown) on which a plurality of ink jet heads are mounted. In the present embodiment, the ink jet head has four colors of black (K), cyan (C), magenta (M), and yellow (Y), and ink droplets are respectively formed corresponding to binarized image data. Discharge.

FIG. 2 shows a processing flow from reception of input binary image data to printing. FIG. 3 shows an example of a table referred to for selecting a print mode from a print ratio given in the process of FIG.

In the flow of FIG. 2, when input binary image data is received from an external computer terminal device or the like (S
21), the CPU 11 analyzes the received data and prepares one band of print data suitable for recording by the inkjet head (S22). Next, the number of ink dots to be ejected is detected based on the print data for one band (S23), and the printing rate is calculated from the value of the number of dots and the total number of ejectable dots in one band (S24). . Further, a printing mode to be adopted for the band is selected by referring to the table of FIG. 3 based on the printing rate (S25). Based on the selected print mode and print data, each head is driven to perform print processing (S26). This process is repeated until all bands have been recorded (S27).

In the example of the print mode table 30 shown in FIG.
If the printing rate is less than 30%, one pass is set; if it is 30 to 45%, two passes; if 45 to 60%, three passes; and if 60% or more, five passes. However, the number of divisions of the printing rate, the value of the printing rate at the boundary of the division, and the number of passes in each division range are merely examples, and the present invention is not limited to this example.

FIG. 4 is a diagram for explaining the print mode selection process shown in step S25 of FIG. In this example, it is assumed that the number of nozzles per color is 128, the print ratio of the nth band is calculated, and the print mode for that band is selected.

First, the printing rate is calculated from the number of ejection dots in the n-th band and the total number of dots. If the value is P,

P = number of ejection dots in the nth band / total number of dots

= Number of ejection dots in the n-th band / (128 ×
Effective print width (dot)). For example

Effective printing width: 10,000 dots

If the number of ejection dots: 400,000 dots, the printing rate value P is

P = 400,000 / (10,000 × 1)
28) = 0.312

→ The printing rate is about 31%.

Table 3 is based on the calculated printing rate.
With reference to 0, it is determined in which print mode the printing operation should be performed for the nth band. In this case, since the printing rate is 31%, the printing mode is “2 passes”.

Therefore, if a printing operation is performed on this band in two passes, cockling does not occur and the most efficient printing operation without a long printing time can be realized.

Further, a correction table may be provided which defines a correction coefficient for correcting the printing rate of the above-described table 30 based on the type of paper and other various factors. Generally, there are various types of recording media such as plain paper, coated paper, glossy paper, and film, and the likelihood of cockling varies depending on the type. The likelihood of cockling also changes depending on the temperature and humidity of the environment.

From this point of view, FIG. 5A shows a correction table 31 in which a correction coefficient for the printing rate is set according to the combination of the paper type and the temperature range of the environment. FIG. 5B shows a correction table 31 in which a correction coefficient of a printing rate is set according to a combination of a paper type and an environmental humidity range.
Is shown. Preferred values of these correction coefficients can be obtained experimentally. The numerical values shown are merely examples, and the present invention is not limited to these. If such correction tables 31 and 32 are prepared and the printing ratio is corrected before selecting the printing mode, it is possible to select a more appropriate printing mode.

Although the preferred embodiment of the present invention has been described above, various modifications and changes are possible. For example,
The conditions and result parameters of the tables shown in FIGS. 3 and 5 need not exist as independent tables, but may exist in a form incorporated in the condition determination and result processing in the control program. Therefore, in the present specification, parameters existing in such a program are considered to be tables in a broad sense.

[0033]

According to the present invention, in the processing of the ink jet recording apparatus, the printing rate of the band-shaped unit area is determined, the printing mode is selected based on the printing rate, and the printing operation is performed in the printing mode, whereby the cock is operated. The printing time can be reduced as much as possible while suppressing the occurrence of rings.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of an inkjet recording apparatus according to the present invention.

FIG. 2 is a flowchart showing a processing flow from input data reception to printing of the inkjet recording apparatus of FIG. 1;

FIG. 3 is a diagram showing a page for selecting a print mode from a calculated print ratio according to the embodiment of the present invention.

FIG. 4 is a diagram for explaining print mode selection in the embodiment of the present invention.

FIG. 5 is a diagram illustrating a correction table applied to a printing rate based on a combination of a paper type and a temperature and a paper type and a humidity according to the embodiment of the present invention.

[Explanation of symbols]

 11 CPU 12 RAM, 13 ROM 14 Interface unit (I / F) 15 Liquid crystal display (LCD) 16 Key operation unit (KEY) 17 Printing unit 30 Print mode table 31, 32 Correction table

Claims (6)

[Claims] 1. An ink jet recording method for repetitively scanning a recording head having a plurality of ejection openings for ejecting ink in a direction different from the arrangement direction of the ejection openings to sequentially record an image in each band-shaped unit area. A printing rate of a band-shaped unit area to be recorded by scanning of the recording head is calculated based on the data, and a printing mode for the unit area is selected based on the calculated printing rate. An ink-jet recording method, wherein the recording of the unit area is performed in a printing mode. 2. The ink jet recording method according to claim 1, wherein said print mode is selected from a single pass system and a multi-pass system including at least a two-pass system. 3. An ink-jet recording apparatus for repetitively scanning a recording head in which a plurality of ejection ports for ejecting ink are arranged in a direction different from the arrangement direction of the ejection ports to sequentially record an image in each of the belt-shaped unit areas. A carriage on which a plurality of recording heads are mounted and scanned over a recording medium; conveying means for conveying the recording medium in a direction substantially orthogonal to a scanning direction of the carriage; and the plurality of recording heads based on image data A printing unit that discharges ink, and a printing control unit that can change a printing mode for each band-shaped unit area corresponding to the scanning of the carriage, wherein the printing control unit performs printing on a printing target based on the image data. The printing rate of the band-shaped unit area is calculated, and a printing mode for the unit area is selected based on the calculated printing rate. The carriage to perform recording of the unit areas in the print mode, the ink jet recording apparatus characterized by controlling the conveying means and the printing means. 4. An ink jet recording apparatus according to claim 3, wherein said print mode is a single-pass system and a multi-pass system including at least a two-pass system. 5. The ink jet recording apparatus according to claim 3, further comprising a table for selecting the print mode according to the calculated print ratio. 6. An ink jet recording apparatus according to claim 3, further comprising a correction means for correcting the calculated printing ratio based on various factors.