JPH0596728A - Ink jet printer - Google Patents

Abstract

PURPOSE:To provide an ink jet printer in which resolution can be selected and printing can be carried out at a resolution higher than the interval of nozzles. CONSTITUTION:A rotary member 3 is disposed, rotatably in a plane parallel with a printing plane, in front of an ink jet head 1. First to eighth nozzles 4a-4h are arranged longitudinally (in subscanning direction) in series at predetermined intervals (a) in front of the rotary member 3. A servo motor is mounted on a carriage 5 with the rotary shaft thereof being coupled with the rotary member 3. The rotary member 3 is driven by means of the servo motor to rotate in a plane parallel with the printing face of a paper thus modifying the arranging angle of the plurality of nozzles 4a-4h arranged in series on the rotary member 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer adapted to print on paper by ejecting ink.

[0002]

2. Description of the Related Art In this type of ink jet printer, a plurality of nozzles are arranged in series in the vertical direction on the surface of an ink jet head which faces the paper. Then, during the lateral movement of the inkjet head, ink is ejected from each nozzle onto the paper, whereby printing is performed on the paper.

[0003]

Therefore, the vertical resolution of the printer is determined by the distance between the vertically adjacent nozzles, and the resolution can be changed as well as the resolution not less than the distance between the adjacent nozzles. It was also impossible to select arbitrarily.

The present invention has been made in order to solve the above problems, and an object thereof is to be able to select a required resolution and perform printing at a high resolution equal to or greater than the nozzle interval. To provide.

[0005]

In order to achieve the above object, in the present invention, an ink jet head is provided so as to be capable of reciprocating in the horizontal direction, and ink is ejected from nozzles arranged in series on the ink jet head in the vertical direction. In the ink jet printer adapted to print on the paper, the arrangement angle of the nozzles can be changed within a plane parallel to the printing surface.

[0006]

Therefore, according to the present invention, by changing the arrangement angle of the nozzles, the vertical interval between the adjacent nozzles is changed. Therefore, as the arrangement angle of the nozzles is lowered, the vertical interval between the adjacent nozzles becomes narrower and the resolution can be increased.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 3, the inkjet head 1 is supported so as to be capable of reciprocating in the lateral direction (main scanning direction) along two guide rods 2 arranged in parallel with each other, and as shown in FIG. A circular recess 6 is formed in the front part thereof. The front circular rotary member 3 is rotatably housed in the recess 6 in a plane parallel to the printing surface. The first to eighth nozzles 4a to 4h are arranged in series in the vertical direction (sub-scanning direction) on the front surface of the rotating member 3 at predetermined intervals a. Then, while the inkjet head 1 is reciprocally moved in the lateral direction within a predetermined area facing the paper Y, ink is ejected from the nozzles 4a to 4h onto the paper Y to perform printing.

A servo motor 7 such as a pulse motor is arranged on the carriage 5, and its rotation shaft is connected to the rotating member 3. Then, the driving of the servomotor 7 causes the rotating member 3 to rotate in a plane parallel to the printing surface of the sheet Y, thereby changing the arrangement angle of the plurality of nozzles 4a to 4h arranged in series on the rotating member 3. To be done.
Further, the arrangement angle of the nozzles 4 is set in a plurality of stages from a state where the arrangement direction line S of the nozzles 4 is 0 degree with respect to the vertical direction line F to a predetermined angle (45 degrees) in the counterclockwise direction in the drawing. It

FIG. 4 shows a circuit configuration of components related to the operation of changing the arrangement angle of the nozzles 4 of the ink jet printer. A CPU (Central Processing Unit) 8 controls the operation of the entire device based on a program stored in a ROM (Read Only Memory) 9. A RAM (random access memory) 10 stores data such as input image information.

The servomotor 7 is driven and controlled by the CPU 8 via the driver 11. The nozzles 4a to 4h of the ink jet head 1 are controlled by the CPU 8 through the driver 12 in terms of ink ejection timing. The buffer 13 is for temporarily storing the data of the ink ejection timing signal to be output to each of the nozzles 4a to 4h, and has therein the nozzles 4a to 4h.
4h number of 1st-8th storage areas 13a-1
3h are provided corresponding to the first to eighth nozzles 4a to 4h, respectively.

The selection key 14 is for selecting the resolution of the print image. Further, the ROM 9 stores data on the array angle of the nozzles 4 corresponding to the resolution of the print image, data on the ink ejection timing corresponding to the array angle, and the like. Then, by operating the selection key 14, the CPU 8 operates the servo motor 7 to rotate the rotating member 3 by a predetermined angle based on the program stored in the ROM 9, whereby the array angle of the nozzles 4 is set to a plurality of stages. Then, the resolution corresponding to the array angle is selected.

Here, when the arrangement direction line S of the nozzles 4 on the rotary member 3 forms an angle of 0 degree with the vertical direction line F, as shown by the solid lines in FIGS. The arrangement angle of the nozzles 4 is 0 degree), and the adjacent nozzles 4a to
Since the interval a of 4h is wide, the resolution of the printed image in the vertical direction is low. Further, as shown by the chain line in FIGS. 1 and 2, when the arrangement direction line S of the nozzles 4 on the rotating member 3 forms an angle of, for example, α degrees with respect to the vertical direction line F (hereinafter, simply the nozzle 4 Array angle is referred to as α degrees), and the adjacent nozzles 4a to
The vertical interval b of 4h is narrowed, and the vertical resolution of the printed image is improved. And the space | interval b can be represented as b = a * cos (alpha).

In the ink jet printer constructed as described above, in order to print on the paper Y, first, the desired resolution is selected by operating the selection key 14, and the arrangement angle of the nozzles 4 is selected. It is set to the angle corresponding to the resolution. Then, while the inkjet head 1 is reciprocally moved in the lateral direction within a predetermined area facing the paper Y, ink is ejected from the nozzles 4a to 4h onto the paper Y to perform printing.

Here, as shown in FIGS. 5A and 5B, the same image is printed with the arrangement angle of the nozzles 4 set to 0 degrees, and the arrangement angle of the nozzles is α degrees. Compare with the case of setting.

That is, when the arrangement angle of the nozzles 4 is 0 degree, for example, when an image as shown in FIG. 5A is printed (the black dots are the printing portion by ejecting ink), the buffer 13 is stored. Is input with the data of the ink ejection timing signal as shown in FIG. As shown in the figure, the first to eighth storage areas 13a to 13a of the buffer 13
In 13h, data of ink ejection timing signals output to the respective driving units of the first to eighth nozzles 4a to 4h are temporarily stored. H is an ink ejection signal, and L is an ink non-ejection signal. Also, T1, T
2, T3 ... Indicates the passage of time. That is, as the time passes, the first to eighth storage areas 13a of the buffer 13
~ 13h alternately outputs the ink ejection signal H and the non-ejection signal L to the respective drive units of the first to eighth nozzles 4a to 4h, and along with the lateral movement of the inkjet head 1, An image as shown in FIG. 5A is printed on the paper Y.

Further, as shown in FIG. 5 (b), when the arrangement angle of the nozzles 4 is α degrees, the buffer 13 shown in FIG.
The data of the ink ejection timing signal as shown in (b) is input. That is, as compared with the case where the arrangement angle of the nozzles 4 shown in FIG.
From the eighth storage area 13a to 13h to the first to eighth nozzles 4
The ink ejection timing signals output to the respective driving units a to 4h are deviated. That is, as shown in FIG. 5B, if the arrangement angle of the nozzles 4 is inclined, the lower nozzles 4 proceed later. Therefore, the timing is set so that the lower the nozzles 4 are ejected, the later the ink is ejected.

As a result, as shown in FIG. 5B, even when the arrangement angle of the nozzles 4 is α degrees, the print image does not tilt, and the same printing as when the arrangement angle of the nozzles 4 is 0 degree is performed. Not only can each nozzle 4a
Since the vertical interval b between 4h and 4h is narrow, the resolution of the printed image is improved.

As is clear from the above, when the arrangement angle of the nozzles 4 is α degrees, the entire vertical direction per scan of the ink jet head 1 is greater than when the arrangement angle is 0 degrees. Print width is narrowed. Therefore, when the inkjet head 1 is moved in the horizontal direction at the same speed as in the case where the arrangement angle of the nozzles 4 is 0 degree at the time of printing, the print image is compressed in the vertical direction and laterally spread.
Therefore, when the nozzle array angle is set to α degrees, it is necessary to reduce the moving speed of the inkjet head 1 or shorten the ink ejection timing cycle of the nozzle 4 in accordance with the array angle α. ..

As described above, by changing the arrangement angle of the nozzles 4, the distance a between the adjacent nozzles 4a to 4h is increased.
Even if the number is constant, printing can be performed at a high resolution equal to or greater than the interval a, and moreover, by changing the arrangement angle of the nozzles 4 to a plurality of stages, a plurality of resolutions can be selected and printing according to the purpose can be performed. It can be performed. Further, from another perspective, the print image can be reduced by changing the arrangement angle of the nozzles 4, and even in this case, the number of dots forming the print image does not decrease.
The resolution of the reduced print image does not decrease.

The present invention is not limited to the above-described embodiment. For example, as shown in FIG. 7, a flat rectangular rotating member 15 can be rotated at one end on the front surface of the ink jet head 1. 1 to 8 are provided on the rotating member 15
The nozzles 4a to 4h may be arranged in series, and the configurations of the respective parts may be arbitrarily modified and embodied without departing from the spirit of the present invention.

[0021]

As described above in detail, according to the present invention, it is possible to select the resolution, and it is possible to perform printing with a high resolution equal to or greater than the nozzle interval.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing an embodiment of an inkjet printer embodying the present invention.

FIG. 2 is a partial front view of the inkjet printer.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a block diagram showing a circuit configuration of components related to a change operation of an array angle of nozzles of an inkjet printer.

5A and 5B are views showing a printing state on a sheet by an inkjet printer, in which FIG. 5A is a printing state when the nozzle arrangement angle is 0 degree, and FIG. 5B is a printing state when the nozzle arrangement angle is α degree. It is a figure which shows a state.

6A and 6B show data of an ink ejection timing signal, in which FIG. 6A shows ejection timing signal data when the nozzle arrangement angle is 0 degree, and FIG. 6B shows when the nozzle arrangement angle is α degree. 6 is a diagram showing data of an injection timing signal in FIG.

FIG. 7 is a partial front view showing another embodiment of the present invention.

[Explanation of symbols]

1 inkjet head, 3 rotating members, 4a to 4h
First to eighth nozzles, Y paper.

Claims (1)

[Claims] 1. An inkjet printer in which an inkjet head is provided so as to be capable of reciprocating in a horizontal direction, and ink is ejected from nozzles serially arranged in a vertical direction on the inkjet head to perform printing on a sheet,
An ink jet printer characterized in that an arrangement angle of the nozzles can be changed in a plane parallel to a printing surface.