JPH08238806A - Method and apparatus for recording multicolor image - Google Patents

Abstract

PURPOSE: To improve a recording speed efficiently by changing a relative transfer speed between a head and a recording material every time of recording each color corresponding to the pitch of each color. CONSTITUTION: A printing control part 103 reads color image data stored in an image memory 109 synchronously with a line lock to generate a current passing pulse for controlling a head driving part 111. A transportation part 107 drives a motor 113 based on a print clock so that a printed matter is feedback-controlled. For the print clock which determines a transportation pitch in the sub-scanning direction, it is formed at different timing for each color, and its speed is increased in the order of KCMY. A relative transportation speed for each color is set higher when a color with a coarse pitch in the sub- scanning direction is recorded as compared with a color with a fine pitch so that the recording speed can be improved efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor image recording method and apparatus in which the pitch in the sub-scanning direction is different for each color.

[0002]

2. Description of the Related Art In recent years, various recording means capable of recording multicolor images have been proposed. When recording a multi-color image, since pixels are overlapped for each color, color misregistration easily occurs,
It may cause color moire. As means for avoiding color moire when recording a multicolor image, for example, Japanese Patent Application No. 6-
The image recording method disclosed in Japanese Patent No. 328117 can be used. In this recording method, a multi-color image is recorded by changing the pitch in the sub-scanning direction for each color, and the resolution image data is interpolated according to the position of the gradation image to 300 lines / inch. The set line pitch of Y, M, C, and K per unit length in the sub-scanning direction is 3
Convert to 00 lines / inch, 400 lines / inch, 500 lines / inch and 600 lines / inch. As a result, color moire is effectively avoided.

[0003]

As described above, in order to avoid color moire that occurs when recording a multicolor image, the data of the gradation image is interpolated according to the position of the gradation image, and the sub-pixels of each color are sub-processed. The pitch in the scanning direction is variable.
Conventionally, when a multicolor image is recorded, the recording speed of each color is set to the same speed because the pitch of each color in the sub-scanning direction is the same. However, when recording a multicolor image by changing the pitch in the sub-scanning direction for each color, it is not necessary to record at the same speed for each color, and it is possible to record at a different speed for each color. is there.

The parameters that determine the printing speed include the data transfer speed and the printing scan speed, and the printing speed can be increased by setting each parameter to a high speed. However, in recording each color, if the above parameters are uniformly set at high speed, the data processing mechanism and the transport mechanism are burdened, and the cost of the recording apparatus is increased.

Therefore, the present invention has been made in view of the above circumstances, and a multicolor image recording method capable of efficiently improving the recording speed when recording is performed by making the pitch in the sub-scanning direction different for each color. And to provide a device.

[0006]

In the multicolor image recording method according to the present invention, a head having a plurality of recording elements arranged in the main scanning direction and a recording material are relatively moved by a plurality of lines in the sub-scanning direction for each color. Is a multi-color image recording method in which the pitch of each color in the sub-scanning direction is made different, and the relative moving speed between the head and the recording material is recorded for each color according to the pitch of each color. It is different from.

Further, the relative movement speed between the head and the recording material when recording a color set at a coarse pitch is faster than the relative movement speed when recording a color set at a fine pitch. It has at least one set relationship. The multicolor image recording apparatus according to the present invention generates the first reference signal for controlling the conveyance of the recording material in the sub-scanning direction by making the pitch in the sub-scanning direction different each time each color is recorded. A signal generating means and a second reference signal for generating a second reference signal for selectively energizing the head, in which a plurality of recording elements are arranged in the main scanning direction, by a plurality of energizing pulses carrying image information of each color. A multicolor image recording apparatus for recording each color in a frame-sequential manner by including a generation unit, wherein the first reference signal generation unit is configured to control a conveyance speed of the material when recording a color set at a coarse pitch. A first reference signal having a different conveying speed each time each color is recorded so as to have at least one relationship set at a speed higher than the conveying speed of the recording material when recording a color set at a fine pitch. Generate Than it is.

[0008]

According to the above-mentioned means according to the present invention, when the multi-color image is recorded in the plane-sequential manner by making the pitches of the respective colors different from each other in the sub-scanning direction, the relative moving (conveying) speed of each color depends on the pitch of each color. Can be changed respectively. The relative movement (conveyance) speed for each color is set to be higher when a color having a coarse pitch is recorded than when a color having a fine pitch in the sub-scanning direction is recorded. The relative movement (conveyance) speed of each color does not have to be variable for all colors, but may be variable for at least one color.

In the case of the prior art in which each color is set to have the same pitch in the sub-scanning direction and each color is recorded in the field sequential manner, when recording all colors, the data transfer speed of each color image data and the relative movement in the sub-scanning direction. The (conveyance) speed is set to be equal. On the other hand, in the recording technology of the present invention, in which recording is performed with different pitches in the sub-scanning direction for each color,
Since the size of the image data carrying each color image information is different, the data transfer rate is different for each color.

When the transfer speed of the image data of each color is set on the basis of the speed at which the image data of a color having a large data size, that is, a color having a fine pitch is transferred at the same relative movement (conveyance) speed that is set. There is a margin in speed when transferring image data of a color having a small data size, that is, a color having a coarse pitch. If the transfer speed is made constant for each color, the relative moving (conveying) speed is shortened and some colors can be recorded. If the relative movement (conveyance) speed can be shortened, the recording time until the field sequential recording of each color is completed can be shortened.

When thin film transfer recording is performed by applying the present invention, the thin film transfer material is also peeled off at a high speed as the relative moving (conveying) speed increases, so that the shape of the recording dots becomes smooth and the image has a rough feeling. It will be reduced. As the recording element, a thermal head, a liquid crystal shutter, a PLZT shutter, a line head or a serial head using an LED head or an EL head, and further laser recording can be applied. Further, the recording device may be one that records in multi-color in a frame sequential manner, and can be applied to offset printing, gravure printing, stencil printing or screen printing.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which, in multi-color surface sequential recording in which the pitch in the sub-scanning direction is different for each color, the transfer speed of the transferred material in the sub-scanning direction is made different for each color. The gradation image is recorded by four color separation of black (K), cyan (C), magenta (M) and yellow (Y).

The line clock generator 101 which is the second reference signal generating means is a line clock (LINECL) which is the second reference signal for driving a head (not shown).
K) is generated and input to the print control unit 103. Also,
The print clock generation unit 105, which is a first reference signal generation unit, uses the first for setting the conveyance speed in the sub-scanning direction.
The print clock (PRNCLK) that is the reference signal of (1) is generated and input to the conveyance control unit 107.

The print control unit 103 reads out the image data of each color stored in the image memory 109 in synchronization with the line clock and generates energizing pulses for controlling the head drive unit 111. The head drive unit 111 selectively energizes a head (not shown) based on the energization pulse. The head has a plurality of heating resistors arranged in the main scanning direction.

The conveyance control unit 107 drives the motor 113 based on the print clock, and thereby the transfer target is controlled to be returned.

FIG. 2 shows the timing of the line clock, the print clock and the energizing pulse. The energizing pulse is shown as low active. At the timings shown in FIG. 2, the print pitch in the main scanning direction is constant for each color, and the transport pitch in the sub scanning direction is changed for each color. That is, the line clock is the same for each color, and the energizing pulse of the same timing is generated for each color in synchronization with the timing of the line clock.
On the other hand, the print clocks that determine the conveyance pitch in the sub-scanning direction are generated at different timings for each color, and the speeds are set to increase sequentially in the order of KCMY. The speed of the print clock generated for each color is inversely proportional to the conveyance pitch of each color in the sub-scanning direction.

In this embodiment, the pitches of KCMY in the sub-scanning direction are 600 lines / inch, 500 lines / inch, 400 lines / inch and 300 lines / inch, respectively.
Since it is set to inches, the print clock speed is set to increase sequentially in the order of KCMY.

3 and 4 show the flow of printing processing. First, the line clock speed is set (S101),
Set the transferred sheet to the initial position. After that, the paper feed speed for K color is set (S102), and K color is printed (S1).
03). When printing of the K color for a predetermined line is completed (S104
Yes), after the transfer target sheet is returned to the initial position, the paper feed speed for C color is set (S105), and C color is printed (S106).

When the C color has been printed for a predetermined number of lines (S1
07Yes), after returning the transfer target sheet to the initial position,
The paper feed speed for M color is set (S108), and M color is printed (S109). When printing of the M color for a predetermined line is completed (Yes in S110), the transfer target sheet is returned to the initial position, the Y-color paper feed speed is set (S111), and the Y color is printed (S112). After the printing of the Y color for the predetermined line is completed (S113 Yes), the printing process is ended.

Below, the pitch per unit length of each color of KCMY in the sub-scanning direction is 600 lines / inch,
500 lines / inch, 400 lines / inch and 30
The print speed when 0 line / inch is set will be described. The pitch in the main scanning direction is set to 300 dpi defined by the head arrangement pitch. The unit pulse of the print clock is defined by a feed pitch of 3000 lines / inch, so the number of pulses per line of each color of KCMY is 5 pulses / line,
6 pulses / line, 7.5 pulses / line and 10 pulses / line are set.

First, the line clock cycle is set prior to printing of each color, and then the print clock cycle is set. Since the transfer pitch of the transferred material is different for each color as described above, if the cycle of the line clock is set to 3300 μsec, the cycle of the print clock for each color of KCMY is 3300/5.
= 660 μsec, 3300/6 = 550 μsec, 3
300 / 7.5 = 440 μsec and 3300/10 =
It becomes 330 μsec.

Table 1 shows the recording time when the transport speeds of the respective colors in the sub-scanning direction are made different according to the pitch, as Example 1. As a comparative example, the recording time when the conveyance speeds of the respective colors are set to be the same is shown. In addition, as the second embodiment, the recording time when the transport speed is changed only for the Y color is shown.

[0023]

[Table 1]

As is clear from Table 1, the recording time can be shortened by making the carrying speed of each color different, or making the carrying speed different for at least one color.

In the above-described embodiments, the two-dimensional recording in which the one-dimensional array direction of the recording elements is defined as the main scanning direction and the direction orthogonal to the main scanning direction is defined as the sub-scanning direction has been described. However, it goes without saying that the one-dimensional array direction of the recording elements may be defined as the sub-scanning direction and the direction orthogonal to the sub-scanning direction may be defined as the main scanning direction.

[0026]

According to the invention described above, in the case where each color is recorded face-sequentially with different pitches in the sub-scanning direction for each color, the relative moving speeds in the sub-scanning direction are changed according to the pitch of each color. By varying, the recording time can be shortened efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a timing chart showing the timing of each signal generated in the block diagram shown in FIG.

FIG. 3 is a flowchart showing the flow of recording processing.

FIG. 4 is a flowchart showing the flow of recording processing.

[Explanation of symbols]

 101 line clock generation unit 103 print control unit 105 print clock generation unit 107 transport control unit 109 image memory 111 head drive unit 113 motor

Claims (3)

[Claims] 1. A head in which a plurality of recording elements are arranged in the main scanning direction and a recording material are relatively moved in the sub scanning direction by a plurality of lines to record each color in a plane sequential manner, and the pitch of each color in the sub scanning direction is set. A multicolor image recording method, wherein the relative moving speeds of the head and the recording material are made different each time each color is recorded according to the pitch of each color. 2. The relative movement speed between the head and the recording material when recording a color set at a coarse pitch is faster than the relative movement speed when recording a color set at a fine pitch. The multicolor image recording method according to claim 1, wherein the multicolor image recording method has at least one set relationship. 3. A first reference signal generating means for generating a first reference signal for controlling conveyance of a recording material in the sub-scanning direction by making the pitch in the sub-scanning direction different for each color, and a plurality of means. A second reference signal for selectively energizing the head, in which the recording elements are arranged in the main scanning direction, with a plurality of energizing pulses carrying image information of each color.
A multi-color image recording apparatus for recording each color in a field sequential manner by including the reference signal generating means of the above, wherein the first reference signal generating means of the material when recording a color set at a coarse pitch. A first conveying speed that differs each time each color is recorded so that there is at least one relationship that is set higher than the conveying speed of the recording material when a color whose conveying speed is set to a fine pitch is recorded.
A multicolor image recording apparatus, wherein the multicolor image recording apparatus is configured to generate the reference signal.