JPH01114448A - Color ink-jet recorder - Google Patents

Abstract

PURPOSE:To produce a high-quality image without color smearing by scanning each line on a recording medium with ink-jet heads a plurity of times in a mixed-color mode so that the heads can output color ink at given time intervals. CONSTITUTION:A recording head unit 90 for color imaging has an array of four respective heads 9A, 9B, 9C, and 9D for cyan, magenta, yellow, and black, arranged along the scanning direction. This head unit is adapted to print a given pattern of ink dots on a recording medium 1 placed in front of it. Each line on a recording medium 1 is scanned with heads 9A, 9B, 9C, and 9D a plurality of times in a mixed-color mode so that the ink-jet heads can output color ink at given time intervals. Therefore, the limit of ink absorption of paper will not be exceeded, and a high-quality color image can be obtained without smearing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording device, and particularly to a color inkjet recording device that performs color printing.

[Prior Art] As shown in FIG. 2, red (hereinafter referred to as R), green (hereinafter referred to as G), and blue (hereinafter referred to as B) are complementary colors to Y, M, and C. Therefore, as shown in FIG. 3, in the case of a color recording apparatus, R is formed by overlapping yellow (hereinafter referred to as Y) and magenta (hereinafter referred to as M). Similarly, G is formed by overlapping Y and cyan (hereinafter referred to as C), and B is formed by overlapping C and M. Also, Y
When the three MC colors are superimposed, it becomes black, so in principle,
The three primary colors are sufficient, but the black created by mixing the three colors looks muddy. For this reason, color recording devices that use black ink are common.

[Problems to be Solved by the Invention] In the inkjet recording method, paper absorbs ink to form figures, characters, and symbols.

However, there is a limit to the ink absorption capacity of paper. Therefore, when shapes, characters, and symbols are formed by overlapping colors as in a color printer, the amount of ink on paper differs when printing with one color ink and when printing with two color inks overlapping. Therefore, if the ink absorption capacity of the paper exceeds the limit, the ink will smear and the image quality will be significantly degraded.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color inkjet recording apparatus that eliminates the above-mentioned deficiencies and forms colors with high image quality without bleeding even in, for example, two-color overlapping color mixing mode.

[Means for solving the problems] The present invention includes a plurality of inkjet heads corresponding to each color,
and means for causing the head to scan the same position on the recording medium multiple times so as to obtain a predetermined color ink ejection time interval between each inkjet head in a multi-color mixing mode.

[Function] According to the present invention, predetermined color ink is ejected between each inkjet head in the multi-color mixing mode, ``fli!''. 1
Spacing? The head is scanned over the same position on the recording medium multiple times so that tJ is reached.

[Example J] The present invention will be specifically described below with reference to the drawings. FIG. 1 shows an inkjet type color inkjet recording apparatus suitable for carrying out the present invention.

In FIG. 1, a recording medium 1 such as paper or a plastic sheet is supported by conveyance rollers 2.3 consisting of a pair of upper and lower rollers, and is moved by a conveyance roller 2 driven by a sheet feed motor 4 as indicated by the arrow It is transported in the A direction. A pair of guide shafts 5 are provided in front of and parallel to the conveyance roller 2.3, that is, a carriage 6 is driven by a carriage motor 7 along this guide shaft.
is reciprocated in the direction of arrow B via the wire 8.

A recording head unit 90, which is an inkjet head, is mounted on the carriage 6.

This recording head unit 90 is for creating a color image, and consists of four recording heads 9A, 9B, 9G, and 9D arranged in the scanning direction and recording with cyan, magenta, yellow, and black inks. ing. A recording section in which ink ejection ports are arranged is provided on the front surface of each recording head, that is, at a location facing the recording medium 1 at a predetermined interval (for example, 0.8 mm). That is, ink ejection ports are formed at a predetermined pitch on the surface of the recording unit facing the recording medium 1, and the electrothermal transducer (heating resistor, etc.) of each ink ejection port is driven (electrified heating) based on the recording information. ) to foam the ink, and the expansion pressure forms flying ink droplets, and recording is performed while the ink dots are attached to the recording medium 1 in a predetermined pattern.

Each recording head is equipped with a circuit board for a drive circuit (heat driver) for driving the recording head as described above.

In FIG. 1, the control circuit (CPU) of the recording apparatus and the ROM, RAM, etc. attached thereto are formed on a control board, and this control circuit receives command signals and data from a host machine 14 such as a computer. Receive the signal (recorded information),
Based on this, a heat voltage is applied to each of the recording heads 9A to 9D via the heat driver together with drive sources such as various motors.

An operation panel 160 attached to the exterior case (not shown) of the recording device includes an online/offline switching key 16.
In addition to keys such as A, line feed key 16B, form feed key 16c, and recording mode switching key 16D,
Several warning lamps such as an alarm lamp 16E and a power lamp 16F are provided.

FIG. 4 is a block diagram showing a control system of the inkjet recording apparatus of FIG. 1.

In Figure 4, CPU (microprocessor) 2
1 is connected to a host machine 14 such as a computer via an interface 22, and receives command signals (commands) and recorded information signals incorporated in a data memory 23 from the host machine, as well as ROMs such as a program memory 24 and a working memory 25. The recording operation is controlled based on a program stored in, for example, the one shown in FIG.

The CI'U 21 controls the carriage motor (Fig. 1) and the sheet feed motor 4 (Fig. 1) via the output boat 26 and the motor driver 27, and also controls the carriage motor 4 (Fig. 1) based on the recorded information stored in the data memory 23. The recording heads 9A to 9D are controlled via a head control circuit 29.

Reference numeral 30 in FIG. 4 is a sheet sensor that detects whether or not the recording medium l exists between the conveyance rollers 2 and 3 (FIG. 1), and sends a detection signal to the CPU 121 via the manual boat 31. is transmitted.

Each operation key 1B8 to 16 on the operation panel 160 described above
The output from D (FIG. 1) is connected to C via input port 32.
The signal is transmitted to the PU 21, and the output boat 3
An electrical signal is supplied via 6.

Reference numeral 33 in FIG. 4 is a dip switch provided on the bottom of the exterior, and its output is transmitted to the CPU 21 via an input port 34.

In FIG. 4, a logic drive voltage VCC (5V
), various motor drive voltages VM (30V), reset voltage rlEsET, heat voltage (head voltage) Vll(2) for heating the dot forming elements of each recording head.
5V) and backup voltage VD for recording head protection.
DI+ is output.

An embodiment will be described below with reference to the flowchart shown in FIG.

After the control unit initial processing (S101) when the power is turned on, C
The Pu 21 is idling while monitoring the input of control commands and print data from the host machine 14 connected to the printer via the interface 22 (5102).
).

In this embodiment, it is assumed that the color bit image settings with the host machine are executed according to the following specifications.

ESCr DATA LENGTII IMAG
E Takes the format of OAT.

ESCr indicates a color bit image setting command.

What is DATA LEN'GTH?
This 1-byte parameter indicates the total number of bytes of image data in the tree command.

The first "n" bytes of image data are red, the next "n" bytes of image data are green, and the last "n" bytes of image data are blue.

At 5102, the host machine 14 connected to the printer
When the print data is manually inputted from 5103, the CP
U21 stores data in the reception RG[l buffer provided in the data memory 23 as shown in FIG.

“#” corresponds to a recording dot. CPl] 21 determines whether the reception of prescribed print data from the host machine 14 is complete (51
Repeat steps 5102 to 5104 until 04).

When the CPII 21 finishes receiving the specified print data from the host machine 14, the CPII 21 transfers the data in the RGB buffer of the data memory 23 to the print YMCBk buffer provided in the data memory 23 using a conversion circuit as shown in FIG. The YMCBk data obtained by conversion (the conversion table is shown in FIG. 7) is stored separately as 1-pass printing information for the first color and 2-bus printing information for the second color, as shown in FIG.

ESCr 0811 (N to DAT8L) from the above host
GTII) AA to... (RDATA) CCI+...
・(G DATA)FOI+...(B D
ATA) is sent, the data is stored in the reception buffer as shown in FIG.

When expanding from IIGB to YMCBk, in this example, YMCBk heads 9A to 9D are mounted on the carriage as shown in FIG. 1, so there is a gap between each head. cpυ21 to correct the printing interval
When developing into YMCBk, data is stored while inputting 00 data in the print interval section in advance.

After storing the print data expanded from RGB to YMCBk,
The CPU 21 controls the start of printing (5106). 51
At step 06, the CPU 21 excites the carriage 7 in the right direction from the output boat 26 via the driver 27 in order to move the carriage 29 in the PT direction. Next 51
At 07, the control circuit 29 sends tl to the heads 9A to 9D.
Set the print data (first color print data expanded to YMCBk). After setting, in step 5108, a prescribed pulse is applied to the head. The pulse width at this time is defined by the following timer tl (5109).

After time-up, power to the head is cut off (5110).

5ill, the recording cycle counter provided in the working 25 is incremented by 1 each time the current is applied. The recording cycle counter determines whether printing is complete (511
2). If the recording cycle counter does not exceed the specified print dot value at 5112, the process returns to 5106;
Repeat operations 5106-5112. If the recording cycle counter exceeds the specified print dot value in 5112, the process advances to 5113, and the carriage motor 7 is excited to the left to move the carriage 29 in the CR direction from the output boat 26h) via the driver 27. Execute CR processing. Thereafter, when the CR process is completed, the recording medium fixing timer, which is a feature of the present invention, is turned on to allow time for the ink to be sufficiently absorbed by the paper to elapse (5114).

At 5115, the CpH 21 excites the carriage motor 7 in the right direction from the output boat 26 via the driver 27 in order to move the carriage 6 in the PT direction.

Next, in step 5116, the control circuit 29 sets print data (print data for the second color developed into YMCBk). After setting, in step 5117, a prescribed pulse is applied to the head. The pulse width at this time is determined by the next timer El.
(5118). After time-up, power to the head is cut off (5119).

At 5120, a working 25 is provided for each energization, and the recording cycle counter is incremented by 1. The recording cycle counter determines whether printing is complete (512
1). If the recording cycle counter does not exceed the specified print dot value in 5121, the process returns to 5115 and 5
Repeat operations 115-5121. If the recording cycle counter exceeds the specified print rate value in step 5121, printing of one line is completed.

[Effects of the Invention] As explained above, according to the present invention, recording without color bleeding can be performed.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a bubble jet type inkjet recording apparatus suitable for applying the present invention, Figures 2 and 3 are principle diagrams showing the subtractive color mixing method, and Figure 4 is a diagram of the control system of the recording apparatus. 5 is a flowchart for implementing the present invention, FIG. 6 is a logic circuit diagram for converting from RGB to YMCBk, FIG. 7 is a diagram showing the conversion table, and FIG. 8 is a buffer of this embodiment. It is a figure showing an example of information. 7... Carriage motor, 9... Recording head, 11... Heater, 13... Head drive circuit, 14... Host, 21... CPU Figure 3ARin-moa e Σ

Claims (1)

[Claims] A plurality of inkjet heads corresponding to each color, and means for causing the heads to scan the same position on a recording medium a plurality of times so as to obtain a predetermined color ink ejection time interval between each of the inkjet heads in a multicolor color mixing mode. A color inkjet recording device characterized by: