JP2613205B2 - Dot matrix recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dot matrix recording method, and in particular, is constituted by N dot recording means arranged at a pitch n times a predetermined dot pitch P in the sub-scanning direction. The present invention relates to a dot matrix recording method in which a recording head performs dot recording at the dot pitch P in the sub-scanning direction.

[Related Art] Conventionally, an ink jet printer has been known as an apparatus using the above-described dot matrix recording method. In an ink-jet printer or the like, the dot recording units are arranged at a pitch wider than the required dot recording pitch as described above because it is difficult to arrange the dot recording units at such a narrow interval.

FIG. 2 shows an example of a conventional color ink jet printer. In the figure, reference numeral 1 denotes a platen, which is rotated by a motor 7 to convey a print sheet and perform recording sub-scanning.

Reference numeral 2 denotes a print head which performs reciprocal scanning along the platen 1 by the motor 8 via the belt 8a (printing main scanning). The recording position of the print head 2 is the photo sensor 4
Is detected by detecting the slit of the linear encoder plate 5 at the step S1.

The print head 2 is covered with a cap 3 for preventing the nozzles of the head from drying at a home position outside the platen 1. The opening and closing of the nozzle by the cap 3 is controlled by a motor 6.

The open / closed state of the cap 3 is detected by a sensor 10 such as a microswitch. Print head 2
Is detected by a sensor 11 such as a micro switch.

FIG. 4 shows the print head 2 from the lateral direction.
As shown, the print head 2 has an ink chamber 22 that receives ink supply from a main ink tank (not shown) via a supply unit 21.

The ink chamber 22 communicates with the nozzles 25 and supplies ink to each nozzle. Piezoelectric element 26 around the middle of nozzle 25
By driving the piezoelectric element 26, a pressure wave is generated in the nozzle and the ink droplet 24 is ejected.
Such a structure is provided for each color of ink.

FIG. 5 shows the head 2 from the recording medium. Pc indicates the pitch of each color nozzle. As shown, four nozzles 25 for each color are arranged in the vertical direction, and blocks of nozzles for each color are arranged in the main scanning direction. Here, the colors of the ink are four colors of yellow Y, magenta M, cyan C, and black B.

These mechanisms are controlled by the control unit shown in FIG.

In the above configuration, when the print paper is sent from the platen 1 in the sub-scanning direction by the line feed motor 7 and the paper sensor 9 detects the paper, printing is started.

First, the motor 6 operates to remove the cap 3 from the head. When the cap sensor 10 detects that the cap has been removed, the carriage motor 8 operates and the head 2 moves in the main scanning direction.

The encoder sensor 4 receives the ink discharge timing signal from the encoder 5 and discharges ink. The ink ejection timing signal also serves as a clock signal for the carriage motor 8.

As shown in FIG. 3 (A), the control section of the apparatus is constituted by a CPU 13 constituted by a microprocessor or the like, which controls the operation of each section of the apparatus.

Character and image data to be recorded are input from the input unit 16. The input unit 16 includes a keyboard and an interface circuit with a host system such as a computer.

Inkjet recording operation by printer head 2 is CP
It is controlled by U13 via a driver 17 which mainly performs conversion of voltage or current.

Various sensors 18 for detecting the operation of each part of the device including the cap sensor 10 and the like, and the linear encoder 5
The photo sensor 4 for detecting the position and controlling the recording position
Connected to CPU13.

A line feed motor 7 for rotating the platen 1 to feed paper and perform recording sub-scanning, and a carriage motor 8 for main scanning of the printer head 2 are driven by drive circuits indicated by reference numerals 14 and 15. And is controlled by the CPU 13.

In particular, the drive circuit 14 controls the carriage position based on the FG signal detected by the photo sensor 4.

In general, as a means for improving a recording speed in an ink jet printer, there are a method of reducing an ink ejection interval and a method of increasing the number of nozzles. In order to use heads having the same characteristics, it is necessary to increase the number of nozzles.

[Problems to be Solved by the Invention] Usually, the minimum dot pitch P to be printed is the same as the nozzle pitch Pn. However, in the case of a recording head in which this is difficult, Pn is n (integer) of P as described at the beginning. ) Times.
In such a configuration, one screen is printed by performing sub-scanning at appropriate constant intervals.

However, in this method, nozzles that move beyond the print screen at the start and end of printing are not actually used, so that useless scanning is required.

 This is illustrated by FIG.

6 (a) and 6 (b) show how dots are printed in the sub-scanning direction. The number indicates the number of scans in the main scanning direction. The minimum dot pitch is P, the nozzle pitch is
Indicated as Pn.

FIG. 6A shows the case where Pn = 3P, and FIG. 6B shows the case where Pn = 5P. The circles in the figure indicate the arrangement of the ink droplets to be printed in the sub-scanning direction, which are printed on one surface in the main scanning direction. A Pn = P head with four nozzles for each color can perform three scans, and 12 dots in the sub-scanning direction (effective range E) can be printed on a Pn = 3P head and a Pn = 5P head. Six scans are required. Such useless scanning of the print head on the recording medium has a problem that the printing time is lengthened.

[Means for Solving the Problem] In order to solve the above problems, the present invention comprises N dot recording units arranged at a pitch n times the predetermined dot pitch P in the sub-scanning direction. In the dot matrix recording system in which the dot recording at the dot pitch P is performed in the sub-scanning direction by the storage head, the main scanning by the recording head and the sub-scanning at the pitch P are alternately repeated n times, and then P ｛n (N-1 ) The configuration in which dot matrix recording is performed by repeating sub-scanning at a pitch corresponding to + 1 ° is adopted.

[Operation] According to the above configuration, after the sub-scanning of the pitch P is repeated n times and the area is filled with the predetermined area dots, P ｛n (N−1)
The operation of moving the recording head by +1｝ and moving to the unrecorded area reduces the number of dot recording means that are not used because they are off the screen, and unnecessary scanning can be prevented.

EXAMPLES Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

The printer itself may be the same as the conventional one shown in FIGS. 1 to 7, and a detailed description is omitted here.

 In the present invention, the printing scan is performed as follows.

FIGS. 1A to 1D show print examples of the embodiment.
1A to 1D, the number of nozzles of each color is four (=
In the case of N), the number indicates the number of main scans, and the arrow indicates the position of the uppermost nozzle. Here, the minimum print pitch is P, and the nozzle pitch of each color is Pn.

FIGS. 1 (a) to 1 (d) have the same format as FIG.
FIG. 1 (a) shows an embodiment in which Pn = 2P, FIG. 1 (b) shows an embodiment in which Pn = 3P, FIG. 1 (c) shows an embodiment in which Pn = 4P, and FIG. 1 (d) shows an embodiment in which Pn = 10P. is there. Here, the recording dot pitch P = 0.15 m
m, Pn = 1.5 mm.

In this embodiment, in order to perform recording sub-scanning in reciprocating printing with a recording head in which N nozzles are arranged at a nozzle pitch Pn that is n times the minimum dot pitch P (n is an integer of 2 or more), n times are required. The main scanning and the sub-scanning at the pitch P are performed, and then the sub-scanning is performed by the distance P {n (N-1) +1}.

For example, in FIG. 1 (b), after performing the main scanning with the pitch P sub-scanning n times three times, 10P (= ｛3
The sub-scan for (4-1) +1) is performed.

Hereinafter, one screen is printed by repeating this operation. In order to print one screen without waste by this method, Nd = kNn (k is a positive integer) must be satisfied with respect to the number of dots Nd in the sub-scanning direction of one screen.

In this embodiment, Nd is 480 points and k is 12. P is 0.1
Since it is 5 mm, the length in the sub-scanning direction is 72 mm.

As described above, one screen can be printed with the minimum number of scans.

The number of dots in the main scanning direction is 640 in this case. The dot pitches P in the main scanning direction and the sub-scanning direction are the same.
It is 0.15 mm, and the mesh ratio is 1: 1, so that the ratio of the screen width and length in the main scanning and sub-scanning directions is 4: 3.

The present invention is also effective in a rotary drum type printer in which the main scanning direction and the sub scanning direction are different from those of the embodiment. FIG. 1 (e) shows this rotary drum type printer.

The drum 25 is rotating at a constant speed in the main scanning direction.
The recording medium is fixed on the drum 25. The head 2 is intermittently sub-scanned in the direction perpendicular to the paper surface. The 16 nozzles shown have different ink colors, and four nozzles of the same color are arranged in the direction perpendicular to the plane of the drawing. The sub-scanning direction of the print head in FIG. 5 is located in the same direction as the direction perpendicular to the sheet of FIG. 1 (e).

Except that the main scan moves only in the same direction in the rotating system,
The operation is the same as in the above embodiment.

The minimum dot pitch P, the nozzle pitch Pn of the same color, the number N of nozzles of the same color, the number Nd of dots in the sub-scanning direction, and n are integers of 2 or more, and the main scanning is performed n times, and the sub-scanning of the pitch P is performed each time. . The above operation is repeated k times (k is a positive integer), and Nd lines are printed. By satisfying the relationship of Nd = kNn between them, head scanning on the recording medium can be minimized and one screen can be printed in the shortest time. Also, when Nd = kNn-d (d is a positive integer) and d is an extremely small number compared to Nd, one screen can be printed with almost minimum printing time. For example, when Nd = 480 and d = 2, the nozzle that scans the position beyond the print screen is not used only in the last one round of main scanning.

FIGS. 3B and 3C show an example of a processing procedure of the CPU 13 when the above-mentioned recording processing is controlled using the control system of FIG. 3A. Here, the processing when Pn = 2P in FIG. 1A is shown. FIGS. 3B and 3C are continuous at the same alphabetical position.

First, in steps S1 to S3 in FIG. 3B, the motor 7 is driven and the recording paper is fed by the platen 1 to a predetermined recording start position. The end of the feeding to the predetermined position is determined by the paper sensor 9 detecting the recording paper.

Next, in steps S4 to S6, the cap 3 is removed from the printer head 2 at the home position by the same procedure as described above.

Now that the recording is ready, the process proceeds to the recording process from step S7.

First, in step S7, the software counter S is reset to zero. The counter S is for counting the number of sub-scans.

Next, in step S8, the motor 8 is set to move the printer head 2 in the forward direction (the right direction in FIG. 2), and in step S9, the counter M for counting the number of main scans is reset.

In steps S10 to S12, printing is performed dot by dot while moving the printer head 2, and the counter M is incremented by one each time. When the count value of the counter M reaches Nm, indicating that the recording of one line has been performed, the third
The process moves to step S13 in FIG. Here, Nm is the number of recording dots in the main scanning direction.

In step S13, the motor 7 is driven by one dot pitch to perform one-dot sub-scan. This action is a step
In S14, it is counted in the counter S.

In step S15, the motor 8
Is switched so that the printer head 2 moves in the negative direction.

In steps S17 to S19, printing main scanning is performed in the same manner as in steps S10 to S12.

In step S20, the motor 7 is advanced by a pitch of 7 dots. That is, the printer head 2 is advanced from the position of reference numeral 2 to the position of reference numeral 3 in FIG.

In step S21, it is determined whether the number of sub-scans has reached Nd and printing of one page has been completed. Step S21
Is negative, the process of step S8 is repeated.

If step S21 is affirmative, it is checked in step S22 whether or not the printer head 2 is located at the home position. If there is no head at the home position, the printer head 2 is moved to the home position in step S23.

In steps S24 to S26, the cap 3 is put on the printer head 2 by the reverse operation of steps S1 to S3. At this time, if necessary, recovery processing of the printer head 2 is performed.

[Effects of the Invention] As is apparent from the above description, according to the present invention, the sub-scanning direction of the recording head constituted by N dot recording means arranged at a pitch n times the predetermined dot pitch P in the sub-scanning direction. In the dot matrix recording system for performing dot recording at the dot pitch P in the scanning direction, after the main scanning by the recording head and the sub-scanning at the pitch P are alternately repeated n times, P {n (N-1) +1} Since the dot matrix recording is performed by repeating the sub-scanning at the corresponding pitch, the sub-scanning at the pitch P is repeated n times to fill a predetermined area with dots, and then P ｛n (N
The operation of moving the recording head by -1) + 1 ° to the unrecorded area has the excellent effect of reducing the number of dot recording means that are not used because they are off the screen and can reduce unnecessary scanning. .

[Brief description of the drawings]

1 (a) to 1 (d) are explanatory diagrams showing a recording scanning system in the dot matrix recording system of the present invention, and FIG. 1 (e) is an explanatory diagram showing a different configuration in the dot matrix recording system of the present invention. FIG. 2 is an explanatory view showing the main configuration of the ink jet printer, FIG. 3 (A) is a block diagram of a control system for controlling the configuration of FIG. 2, and FIGS. 3 (B) and 3 (C). FIG. 4 is a flowchart showing a recording control procedure according to the present invention, FIG. 4 is an explanatory view showing the structure of the print head of FIG. 2, FIG. 5 is a front view showing the structure of the print head of FIG. 6 (a) and (b) are explanatory views showing a conventional ink jet recording system. 1 ... platen, 2 ... printer head 3 ... cap, 8 ... carriage motor 9 ... paper sensor, 10 ... cap sensor 11 ... home position sensor 13 ... CPU

Claims (1)

(57) [Claims] 1. A recording head comprising N dot recording means arranged at a pitch n times a predetermined dot pitch P in the sub-scanning direction.
In the dot matrix recording method for performing dot recording of the above, after the main scanning by the recording head and the sub-scanning of the pitch P are alternately repeated n times, the sub-scanning of the pitch corresponding to P {n (N-1) +1} is performed. A dot matrix recording method characterized by performing dot matrix recording by repeating the above operation.