JP2005219230A - Printer and printing control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To print a high-quality image with accurate gradation in a printer which forms one pixel by using a plurality of shots. <P>SOLUTION: This printer comprises: a printing data reception part 5 for receiving printing data; a printing-data analysis part 6 for extracting a shot pattern by analyzing the printing data received by the reception part 5; a printing control part 7 for setting a printing scanning direction, according to a position of a carriage; and a shot-pattern changing part 8 for changing the shot pattern, when the printing scanning direction set by the control part 7 is different from a printing scanning direction suitable for the shot pattern. Thus, the printer forms the shot pattern for ejecting an ink droplet, from the first shot. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printing apparatus and a printing control method for forming one pixel by a plurality of shots.

A printing apparatus such as an ink jet printer moves a recording head along the main scanning direction and moves a printing medium such as recording paper along the sub-scanning direction.
In conjunction with these movements, ink droplets are ejected from the nozzle openings of the recording head, thereby recording images, characters, and the like on the print medium.
The ink droplets are ejected, for example, by expanding and contracting a pressure generating chamber that communicates with the nozzle opening. The expansion / contraction of the pressure generating chamber is performed using, for example, deformation of the piezoelectric vibrator.

In the recording head described above, the piezoelectric vibrator is deformed in accordance with the supplied drive pulse, thereby changing the volume of the pressure chamber, and this volume change causes pressure fluctuations in the ink in the pressure chamber. Drops are ejected.
Then, a printing apparatus that supplies gradations to the print image by supplying necessary drive pulses to the piezoelectric vibrator based on the print data, thereby varying the amount of ink droplets ejected from the nozzle openings according to the gradations (For example, refer to Patent Document 1).

Further, as a technique for expressing gradation by varying the amount of ink ejected to one pixel, one pixel is formed by a plurality of ink droplets, and the number of ejections of the plurality of ink droplets is varied to create a gradation. There is a technique called multi-shot that expresses a tone (see, for example, Patent Document 2).
For example, FIG. 6 shows a case where gradation expression is performed by ejecting (dropping) ink droplets up to three times per pixel. This printer head unit has a plurality of (four nozzles A, B, C, D), and each nozzle forms a different pixel. In the example shown in FIG. 6, nozzle A has 3 shots (3 discharges), nozzle B has 2 shots (2 discharges), nozzle C has 1 shot (1 discharge), and nozzle D has 4 levels without shots. Each pixel having a tone is formed.
JP 2003-285453 A JP 2002-301811 A

By the way, as described above, the relationship between the driving pulse (head applied voltage) supplied to the printer head unit and ink droplet ejection when performing multi-shot in which the number of ink droplets ejected to each pixel is different will be described. .
FIG. 7 is an explanatory diagram showing the relationship between the drive pulse supplied to the printer head unit, the waveform indicating the surface state of the ink, and the ink state at the nozzle opening of the printer head unit.

As shown in FIG. 7, when a drive pulse is not applied to the printer head, the ink is held in the nozzle opening and is in a standby state. At the rising edge of the pulse when the drive pulse is applied, the ink temporarily enters the nozzle opening. Be drawn.
Then, the ink in the nozzle opening is vigorously ejected to the outside at the trailing edge of the pulse when the driving pulse is interrupted. After the ink droplets are ejected, residual vibration remains on the ink surface.

  Since the next shot is affected by the residual vibration, the waveform width (PW2, PW3) and period (PD2, PD3) of the drive pulse after the second shot are changed to the waveform width (PW1) of the first shot. Different from the period (PD1) (see FIG. 6A), the ink droplet ejection amount can be accurately adjusted in the second and subsequent shots by controlling the phase and timing of ink droplet ejection.

  For this reason, in order to accurately perform gradation expression and print a high-quality image, it is desirable to eject the first ink droplet from the first shot. Therefore, as shown in FIG. 6A, in the case of nozzle B (1 shot) and nozzle C (2 shots), the drive pulse is applied so that the first ink droplet is ejected from the first shot.

  However, in order to shorten the printing time, in today's printing apparatuses, printing scanning is performed by reciprocation of the printer head unit. In the backward scanning (from left to right) as shown in FIG. In the case of (2 shots) and nozzle C (1 shot), the waveform after the second shot is applied during the first ink droplet ejection without residual vibration, and a desired ink amount cannot be obtained. For this reason, there is a problem that a high-quality image having an accurate gradation cannot be printed.

  The present invention has been made in view of the above problems, and can form a shot pattern for ejecting ink droplets from the first shot in both reciprocating scans, and has an accurate gradation. A printing apparatus and a printing control method capable of printing a high-quality image are provided.

  A printing apparatus according to the present invention is a printing apparatus that forms one pixel by a plurality of shots, and includes a print data receiving unit that receives print data, and a print data analysis unit that analyzes the print data and extracts a shot pattern A print control unit that sets a print scan direction, and a shot pattern change unit that changes the shot pattern when the print scan direction set by the print control unit is different from the print scan direction suitable for the shot pattern. It is characterized by having.

With this configuration, the shot pattern changing unit changes the shot pattern for forming the pixel to a shot pattern suitable for the print scanning direction, so that the first ink droplet can be ejected from the first shot. Thereby, since a desired ink amount can be obtained, a high-quality image having an accurate gradation can be printed.
Further, since the printing apparatus can directly recognize the position of the carriage, the print scanning direction can be set so that the extra movement of the carriage is reduced, and the printing process can be speeded up.

  The print control method according to the present invention is a print control method for forming one pixel by a plurality of shots, the step of receiving print data, and the step of analyzing the received print data and extracting a shot pattern And a step of setting a print scan direction, and a step of changing the shot pattern when the set print scan direction is different from a print scan direction suitable for the shot pattern. .

With this control method, the shot pattern for forming the pixel can be changed to a shot pattern suitable for the printing scanning direction, and the first ink droplet can be ejected from the first shot. Thereby, since a desired ink amount can be obtained, a high-quality image having an accurate gradation can be printed.
Further, the print scanning direction can be set so that the extra movement of the carriage is reduced, and the printing process can be speeded up.

According to the present invention, when ink droplets are ejected, control can be performed so that the ink droplets are ejected from the first shot that forms a pixel, and high-quality images with accurate gradation can be printed. Can do.
In addition, since the printing apparatus itself can directly recognize the position of the carriage, the print scanning direction can be set so that the extra movement of the carriage is reduced, and the printing process can be speeded up.

Hereinafter, embodiments of a printing apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a printing apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the printing apparatus 1 is connected to a host computer 2 via a wired cable, a wireless network, or a network such as a LAN.
The host computer 2 includes a print data creation unit 3 and a data transmission unit 4.
The printing apparatus 1 includes a print data receiving unit 5, a print data analyzing unit 6, a print control unit 7, a shot pattern changing unit 8, a printer head unit 9, and a carriage motor unit 10.

  In the host computer 2, the print data creation unit 3 creates print data of a predetermined shot pattern. The data transmission unit 4 transmits the data created by the print data creation unit 3 to the printing apparatus 1.

  On the other hand, in the printing apparatus 1, the print data reception unit 5 receives the print data transmitted from the data transmission unit 4 of the host computer 2. Then, the print data analysis unit 6 analyzes the print data received by the print data reception unit 5, extracts a shot pattern, and outputs the shot pattern to the print control unit 7.

  The print control unit 7 confirms the current position of the carriage on which the printer head unit 9 is mounted, determines in which direction the reciprocation scans is more suitable, and sets the print scanning direction. For example, when the current position of the carriage is the left end, the print scanning direction is set to the backward direction (the direction from left to right) so that the print scanning is executed from the left end position.

The shot pattern changing unit 8 outputs the shot output from the print control unit 7 when the shot pattern of the received print data is not a pattern suitable for the print scanning direction set by the print control unit 7 as described above. The pattern is changed so as to be a pattern suitable for the scanning direction (for example, rearrangement so as to be a reverse pattern).
Then, the print control unit 7 generates a drive pulse corresponding to the shot pattern suitable for the print scanning direction, and outputs this drive pulse to the printer head unit 9.

The printer head unit 9 drives the printer head unit by the drive pulse output from the print control unit 7.
The carriage motor unit 10 drives the carriage motor in the print scanning direction set by the print control unit 7.

Next, a printing control method by the printing apparatus according to the embodiment of the present invention will be described with reference to FIGS.
2 is a flowchart illustrating a printing control method according to an embodiment of the present invention, FIG. 3 is a diagram illustrating a state during forward printing scan, and FIG. 4 is a diagram illustrating a state during backward printing scanning. FIG. 5 is a diagram illustrating rearrangement by the shot pattern changing unit.

First, the print data creation unit 3 of the host computer 2 generates data including a shot pattern suitable for a predetermined print scanning direction as print data (step S1), and the print data is transmitted from the data transmission unit 4 to the printing device. 1 (step S2).
Here, the predetermined print scanning direction is the forward direction (the direction from right to left), and the shot pattern shown in FIG. 3 is applied. This shot pattern is for four pixels in the vertical direction according to the number of nozzles of the printer head unit 9. One pixel consists of three horizontal shot data, and the ink ejection (shot) signal is represented by “1” and the non-ejection signal is represented by “0”.

In the example shown in FIG. 3, the nozzle A has 3 shots (3 discharges), the nozzle B has 2 shots (2 discharges), the nozzle C has 1 shot (1 discharge), and the nozzles D have no shots. Each pixel having a tone is formed.
Note that the number of shots of each nozzle A, B, C, and D varies depending on the gradation of each pixel of the image to be printed.
In the shot pattern, the first shot is always the ejection signal “1” except when there is no shot. That is, the first shot in the shot pattern of FIG. 3 (the vertical column at the right end) has an ejection signal of “1, 1, 1, 0”.

Then, the printing apparatus 1 receives the print data transmitted from the data transmission unit 4 as described above at the print data reception unit 5 (step S3).
The received print data is input to the print data analysis unit 6, analyzes the received print data, extracts a shot pattern, and outputs it to the print control unit 7 (step S4).

  On the other hand, the print control unit 7 confirms the current position of the carriage on which the printer head unit 9 is mounted, and which direction should be scanned by reciprocation (for example, the carriage travel distance to the print start position is short) Direction) is set, and the print scanning direction is set (step S5).

Next, it is determined whether or not the set print scanning direction matches the predetermined print scanning direction (forward direction) (step S6).
At this time, if the set print scanning direction is a predetermined print scanning direction (forward direction) (YES), a process of step S8 described later is executed. If the set print scanning direction is not the predetermined print scanning direction (forward direction) (NO), the process of step S7 described later is executed.

  When the set print scan direction is not the predetermined print scan direction (forward direction), the print data changing unit 8 reverses the predetermined print scan direction that is a shot pattern corresponding to the set print scan direction ( Rearrangement is performed as shown in FIG. 5 so as to obtain a shot pattern suitable for the backward direction (see FIG. 4) (step S7).

That is, as shown in FIG. 5, a shot pattern (I) for generating a driving pulse (I) at the time of forward printing scanning is referred to as a shot pattern (II) for generating a driving pulse (II) at the time of backward printing scanning. Rearrange as follows.
In this way, by rearranging the shot patterns, the driving pattern for driving the printer head unit 9 is reversed, and the first shot (vertical one column at the left end) is also obtained during the backward printing scan shown in FIG. , “1, 1, 1, 0”.

  The print control unit 7 converts the shot pattern into a drive pulse, outputs the drive pulse to the printer head unit 9, and outputs a command for driving the carriage motor in the set print scanning direction to the carriage motor unit 10. (Step S8).

  The printer head unit 9 drives the head with the drive pulse output from the print control unit 7 (step S9). That is, an ink droplet is ejected by applying an applied voltage of a driving pulse to the piezoelectric vibrator of each nozzle.

On the other hand, the carriage motor unit 10 drives the carriage motor in the print scanning direction according to the command output from the print control unit 7 (step S10).
Thus, for example, as shown in FIG. 3 or FIG. 4, from the nozzles A, B, C, and D of the printer head unit 9, the nozzle A is 3 shots (3 times ejection), and the nozzle B is 2 shots (2 times ejection). The nozzle C forms one shot (one discharge), and the nozzle D forms pixels with four levels of gradations without shots on the printing medium, and executes printing processing.

  As described above, according to the printing control method by the printing apparatus 1 according to the present embodiment, the print data changing unit 8 uses the shot pattern (first shot) suitable for the print scanning direction as the shot pattern for forming pixels. However, the first ink droplets can be ejected from the first shot. Thereby, since a desired ink amount can be obtained, a high-quality image having an accurate gradation can be printed.

Further, when the printing apparatus 1 moves the carriage by autonomous control by an operation other than the printing operation, the host computer 2 cannot directly know the current position of the carriage, and therefore the printing control unit 7 of the printing apparatus 1. It is useful to set the print scan direction.
As described above, as an example in which the printing apparatus 1 moves the carriage by autonomous control, a cleaning operation of the printer head unit that is executed every certain operation time of the printing apparatus 1 can be cited. The cleaning operation forcibly moves the carriage to a predetermined position. For example, if the predetermined position is the left end, the print scanning direction is changed to the backward direction (from left to right so that the printing scan is executed from the left end position. Set to the direction of heading. Thus, by setting the print scanning direction, extra movement of the carriage is reduced, and the printing process can be speeded up.

  In the above embodiment, the predetermined print scanning direction set by the host computer 2 is the forward direction (the direction from right to left), but it may be set to the backward direction (the direction from left to right).

In the above embodiment, an example in which a pixel having four levels of gradation is formed by three shots is described, but the number of shots for forming one pixel may be any other number.
Furthermore, in the above-described embodiment, the example in which the shot pattern is changed to the optimum shot pattern by rearranging the shot pattern has been described. However, another change method may be applied depending on the shot pattern expression method.
Further, the number and configuration of the nozzles can be any number and configuration, and in the case of color printing, it may be applied to the gradation expression of each color.

  The printing apparatus according to the present invention is not limited to an inkjet printer, and may be any printing apparatus that forms one pixel by a plurality of shots.

1 is a block diagram illustrating a printing apparatus according to an embodiment of the present invention. 4 is a flowchart illustrating a printing control method according to an embodiment of the present invention. It is a figure explaining the state at the time of the forward direction printing scan by embodiment of this invention. It is a figure explaining the state at the time of backward printing scanning by embodiment of this invention. It is a figure explaining rearrangement of the shot pattern by an embodiment of the invention. It is a figure explaining the method of forming the pixel with a gradation by multi-shot. It is explanatory drawing which shows the relationship between the drive pulse which drives a head, the waveform showing an ink surface state, and the ink state of a nozzle opening part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing apparatus 2 Host computer 3 Print data creation part 4 Print data transmission part 5 Print data reception part 6 Print data analysis part 7 Print control part 8 Shot pattern change part 9 Printer head part 10 Carriage motor part

Claims (2)

A printing apparatus for forming one pixel by a plurality of shots,
A print data receiving unit for receiving print data;
A print data analysis unit that analyzes the print data and extracts a shot pattern;
A print control unit for setting the print scanning direction;
A printing apparatus comprising: a shot pattern changing unit configured to change the shot pattern when a printing scanning direction set by the printing control unit is different from a printing scanning direction suitable for the shot pattern. A printing control method for forming one pixel by a plurality of shots,
Receiving print data; and
Analyzing the received print data and extracting a shot pattern;
Setting a print scanning direction;
And a step of changing the shot pattern when the set print scanning direction is different from a printing scan direction suitable for the shot pattern.