JP2710943B2 - Inkjet printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly to a printer capable of performing full color printing and black and white printing.

[Conventional technology]

Conventionally, in inkjet printers that can not only draw black and white characters but also color graphics,
It is known that the printing speed of black-and-white characters and the printing speed of color graphics are the same, using black and white nozzles and color nozzles having the same performance.

[Problems to be solved by the invention]

In the conventional inkjet printer described above,
Since the printing speed of black-and-white characters and the printing speed of color graphics are the same, there is a disadvantage that the printing speed of black-and-white characters requiring high-density printing or high-speed printing is restricted.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer capable of high-density printing or high-speed printing of black and white characters while being capable of printing black and white characters and color graphics.

[Means for solving the problem]

An ink jet printer according to the present invention includes a black ink ejection head section having a plurality of recording nozzle rows having n nozzles, and a recording nozzle row having m nozzles (m <n) for each color required for color printing. And the black ink discharge head is moved at a higher speed in the black-and-white print mode than in the color print mode, and the printing timing is set for a plurality of recording nozzle arrays with the number of nozzles n according to the run. And a print control unit for setting.

[Action]

A black ink discharge head having a plurality of recording nozzle rows with n nozzles and a color ink discharge head having a recording nozzle row with m nozzles (m <n) enable monochrome printing and color printing. Further, in the black-and-white printing mode, the recording nozzle array having a large number of nozzles is run at a higher speed than in the color printing mode, so that higher-speed printing can be performed.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing an operation device of an embodiment of the ink jet printer of the present invention, FIG. 2 is an enlarged view of a recording head 6,
FIG. 3 is a block diagram showing an example of a print control unit, FIG. 4 is an enlarged view of a nozzle opening of the recording head 6, and FIG. 5 is a diagram showing another embodiment of the recording head 6.

In FIG. 1, a recording medium 1 such as a sheet of paper or a plastic sheet is supported by conveying rollers 2 and 3 composed of a pair of rollers arranged vertically and is conveyed in the direction of arrow A (sub-scanning direction). A guide shaft 4 is provided in front of the transport roller 3 in parallel with the transport roller 3, and a carriage 5 moves along the guide shaft 4 in the direction of arrow B (main scanning direction)
Reciprocate. A recording head 6 is mounted on the carriage 5. The recording head 6 is composed of a plurality of sets of heads that can be driven independently. In this embodiment, as shown in FIG. 2, 61 to 63 for black ink printing and 61 to 63 for yellow ink printing.
64 for printing magenta ink and 65 for printing cyan ink
66 and four sets of nozzle rows are arranged in the main scanning direction. This nozzle row has a nozzle opening in the sub-scanning direction,
As shown in FIG. 4, an electrothermal converter is provided at the nozzle opening of each of 61 to 63 for black ink printing and m for each of 64 to 66 for color. It has eleven. By driving the electrothermal transducer 40 based on the print data, flying ink droplets are formed, and recording is performed while attaching print dots in a predetermined pattern to the recording medium 1. As described above, the electrothermal converter is used in this embodiment, but in this case, the multi-nozzle structure can be easily achieved as compared with the piezoelectric converter, which is preferable for the printer of the present invention.

The scanning speed and print timing of the recording head 6 during this recording are controlled by a print control unit shown in FIG. In the case of this embodiment, the detector 31 detects a printing mode such as a monochrome printing mode or a color printing mode and outputs a detection signal 36 to the control unit 32. The obtained image information 35 is stored in the line memory 34 in advance, and upon receiving the detection signal 36, a nozzle selection control signal 37 indicating a nozzle corresponding to the print mode and a scanning speed corresponding to the nozzle are indicated. A print speed control signal 39 is output to the print drive unit 33, and a line memory read control signal 38 corresponding to the print speed control signal 39 is output to the line memory 34, and print information is output from the line memory 34 to the print drive unit 33.
, The recording head 6 is driven, and printing is performed while scanning in the main scanning direction at a constant speed.

The ink is supplied to the recording head 6 from an ink tank (not shown) through a flexible ink supply pipe 7.

 Next, the operation of the present embodiment will be described.

Here, the recording head 6 can print 16 dots per 1 mm, and three rows of nozzles 61 to 63 for printing black ink.
Nozzle number n of 256, nozzle row 64 to 6 for color ink printing
The nozzle number m of 6 is 128. In addition, the electrothermal converter 11
When a pulse voltage of 24 V and 10 μsec is applied at a frequency of 3 KHZ, first, the above-described print control unit performs a nozzle selection control signal 37 so that only the black ink nozzle rows 61 to 63 perform printing in the black and white print mode. Since the number of nozzle arrays is 61 to 63, a print speed control signal 39 is output so as to print at three times the speed in the color print mode.
At this time, the nozzle selection control signal 37 controls the ink ejection at an appropriate timing according to the interval between the nozzle rows on the recording head 6 so that the ink droplets are formed at 16 dots per mm in the main scanning direction. In the case of the color printing mode, nozzle rows 64 to 66 for color ink printing, and when using black ink, 128 nozzles of the nozzle row 63 for black ink printing are used, and auxiliary conversion, masking, After performing image processing such as (gamma) correction, the image data is stored in the line memory 34, and thereafter, a printing operation similar to that in the monochrome printing mode is performed.

In this embodiment, when the main scanning speed of the recording head 6 is set to 528 mm / sec in the black-and-white printing mode, and printing is performed in the forward and backward paths of the main scanning, the A4 size recording is laterally fed, thereby obtaining 4.3 sheets per minute. In addition, in the color printing mode, the same printing was performed at 187.5 mm / sec, and printing was performed on the outward path of the main scanning, whereby one full-color print was obtained in 1.5 minutes.

When the black-and-white printing mode has the same printing conditions as the color printing mode, that is, when there is one black ink printing nozzle row and the number n of the nozzles is equal to the number m of the color ink printing nozzle rows (m = n ) Has the same print speed, and cannot be expected to improve the speed in the black and white print mode.

Therefore, in the present invention, the number of nozzle rows for black and white ink is plural, and the number n of the nozzles is larger than the number m of nozzles for the nozzle row for color ink.

 FIG. 5 is a view showing another embodiment of the recording head 6.

Here, the nozzle rows 61, 62, 63 for black ink printing
Are arranged in parallel in the main scanning direction, and the nozzle rows 64, 65, 66 for color ink printing are arranged so as to overlap in the sub-scanning direction.

Further, when performing black ink printing in the color printing mode, the black ink printing nozzle array for the black and white printing is shared, but a separate nozzle array may be provided for the black ink printing for the color printing mode.

〔The invention's effect〕

As described above, the present invention includes a black ink ejection head unit having a plurality of recording nozzle arrays with n nozzles and a color ink ejection head unit having a recording nozzle array with m nozzles (m <n). Therefore, black-and-white printing and color printing can be performed. Further, in the black-and-white printing mode, a recording nozzle array having a large number of nozzles is run at a higher speed than in the color printing mode, so that higher-speed printing can be performed. Further, by setting the printing timing for the forward and backward paths of the main scanning as in claim 2, there is an effect that a printing speed comparable to that of a commercial copying machine can be obtained.

Further, by using the electrothermal conversion element of claim 3 as an ink discharge control means in a nozzle, multi-nozzles can be easily achieved, high-definition printing can be performed, and this is effective for a printer that is used in both monochrome and color.

[Brief description of the drawings]

FIG. 1 is a diagram showing an operating device of an embodiment of the ink jet printer of the present invention, FIG. 2 is an enlarged view of a recording head 6, FIG. 3 is a block diagram showing an example of a print control unit, and FIG. FIG. 5 is an enlarged view of a nozzle opening of the head 6, and FIG. DESCRIPTION OF SYMBOLS 1 ... Recording medium, 2, 3 ... Conveyance roller, 4 ... Guide shaft, 5 ... Carriage, 6 ... Recording head, 7 ... Ink supply pipe, 31 ... Detector, 32 ... Control part, 33 ... Print drive unit, 34 ... Line memory, 35 ... Image information, 36 ... Detection signal, 37 ... Nozzle selection control signal, 38 ... Line memory reading control signal, 39 ... Print speed control signal 40: Electrothermal converter, 61 to 63: Black ink nozzle row, 64 to 66: Color ink nozzle row.

Claims (3)

(57) [Claims] An ink jet printer in which a plurality of recording nozzle rows are arranged in parallel, and while reciprocating in the arrangement direction of the nozzle rows, ink is discharged by an ink discharge control means to perform dot matrix printing on a recording medium. A black ink discharge head section having a plurality of the recording nozzle rows having n nozzles, and a color ink discharge having the recording nozzle rows having m nozzles (m <n) for each color required for color printing. A head unit, and a print control unit that causes the black ink discharge head unit to run at a higher speed in the black-and-white print mode than in the color print mode, and sets print timing for a plurality of recording nozzle arrays with the number of nozzles n according to the run. An inkjet printer comprising: 2. The ink-jet printer according to claim 1, wherein in the black-and-white printing mode, the printing control section sets the printing timing in the forward and backward paths of the main scanning. 3. An ink jet printer according to claim 1, wherein said ink discharge control means is an electrothermal conversion element.