Apparatus for and method of recording image

Abstract

An image recording apparatus (1) causes a recording head (20) to move through a distance corresponding to one half of the recording width of the recording head (20) in a sub-scanning direction each time a recording drum (10) makes one rotation. This, light emitting devices (23, 24) record two line data in advance, and thereafter following light emitting devices (21, 22) record the same line data repeatedly at the same position. This increases the energy of laser light beams given to a recording position on a printing plate (P) to accomplish the recording of an image with reliability. The recording speed is not extremely decreased because not all light emitting devices (21 to 24) are used to make the repeated recordings at the same position on the printing plate (P). Further, the construction of optical systems and driving systems in the image recording apparatus is not complicated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the construction of an image recording apparatus according to a preferred embodiment of the present invention;

FIG. 2 is a timing diagram showing the timings of transfer and recording of line data in a first recording mode;

FIG. 3 shows line data recorded on a printing plate during the second rotation of a recording drum in the first recording mode;

FIG. 4 shows line data recorded on the printing plate during the third rotation of the recording drum in the first recording mode;

FIG. 5 is a timing diagram showing the timings of transfer and recording of line data in a second recording mode;

FIGS. 6A through 6D show the write and read operations of buffer memories in the second recording mode;

FIG. 7 shows line data recorded on the printing plate during the second rotation of the recording drum in the second recording mode;

FIG. 8 shows line data recorded on the printing plate during the third rotation of the recording drum in the second recording mode;

FIG. 9 shows line data recorded on the printing plate during the fourth rotation of the recording drum in the second recording mode;

FIG. 10 is a timing diagram showing the timings of transfer and recording of line data in a third recording mode;

FIGS. 11A through 11D show the write and read operations of buffer memories in the third recording mode;

FIG. 12 shows line data recorded on the printing plate during the second rotation of the recording drum in the third recording mode;

FIG. 13 shows line data recorded on the printing plate during the third rotation of the recording drum in the third recording mode;

FIG. 14 shows line data recorded on the printing plate during the fourth rotation of the recording drum in the third recording mode;

FIG. 15 shows a recording head including a two-dimensional array of light emitting devices; and

FIG. 16 shows an example of line data provided to the light emitting devices when four repeated recordings are made using the recording head including the two-dimensional array of light emitting devices.

Claims

1. An image recording apparatus for recording an image on a recording medium by scanning a surface of the recording medium with a light beam, comprising: a recording head including a plurality of light sources each for emitting a light beam toward the recording medium;a moving part for moving said recording head relative to the recording medium in a main scanning direction and in a sub-scanning direction orthogonal to said main scanning direction; anda controller for controlling said moving part so that said recording head moves through a distance corresponding to one N-th of a recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction, to thereby cause said recording head to make N repeated recordings at the same position on the recording medium, where N is an integer not less than two and different from the number of said light sources.

2. The image recording apparatus according to claim 1, wherein said light sources are arranged in said sub-scanning direction in said recording head, andsaid integer N is a submultiple of the number of said light sources included in said recording head.

3. The image recording apparatus according to claim 2, further comprising a setting part for setting the value of said integer N.

4. The image recording apparatus according to claim 3, wherein said setting part sets the value of said integer N, based on information about the sensitivity of the recording medium or a given recording intensity.

5. The image recording apparatus according to claim 4, further comprising a distribution part for distributing data to said light sources so that said recording head records the same data at the same position on the recording medium.

6. The image recording apparatus according to claim 5, wherein said distribution part includes (N+1) buffers for temporarily holding data to provide the data to said light sources, and performs the process of writing the same data into N out of the (N+1) buffers and reading data from the remaining one buffer while changing the combination of the N buffers in order.

7. The image recording apparatus according to claim 6, wherein each of said light sources is capable of continuously changing the intensity of the light beam.

8. The image recording apparatus according to claim 1, wherein said controller is capable of switching between a first mode in which said controller controls said moving part so that said recording head moves through a distance corresponding to the recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction, and a second mode in which said controller controls said moving part so that said recording head moves through a distance corresponding to one N-th of the recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction.

9. The image recording apparatus according to claim 1, wherein said controller is capable of switching between a mode in which said controller controls said moving part so that said recording head moves through a distance corresponding to one N-th of the recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction, and another mode in which said controller controls said moving part so that said recording head moves through a distance corresponding to one M-th of the recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction, to thereby cause said recording head to make M repeated recordings at the same position on the recording medium, where M is the number of said light sources arranged in said sub-scanning direction.

10. The image recording apparatus according to claim 1, wherein said light sources are arranged in a two-dimensional array extending in said main scanning direction and in said sub-scanning direction in said recording head, andsaid recording head uses some of said light sources different in main scanning position from each other to make repeated recordings at the same position on the recording medium.

11. The image recording apparatus according to claim 10, wherein said light sources are distributed to and disposed in a predetermined number of main scanning positions in said recording head, andsaid recording head uses at least some of said light sources disposed in all of said main scanning positions to make repeated recordings at the same position on the recording medium.

12. An image recording apparatus for recording an image on a recording medium by scanning a surface of the recording medium with a light beam, comprising: a recording head including a plurality of light sources each for emitting a light beam toward the recording medium;a moving part for moving said recording head relative to the recording medium in a main scanning direction and in a sub-scanning direction orthogonal to said main scanning direction; anda controller for controlling said moving part,said controller being capable of switching between a mode in which said controller controls said moving part so that said recording head moves through a distance corresponding to a recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction, and another mode in which said controller controls said moving part so that said recording head moves through a distance corresponding to one M-th of the recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction, to thereby cause said recording head to make M repeated recordings at the same position on the recording medium, where M is the number of said light sources arranged in said sub-scanning direction.

13. A method of recording an image on a recording medium by scanning a surface of the recording medium with a light beam, comprising the steps of: (a) setting the recording medium in a position opposed to a recording head including a plurality of light sources; and(b) emitting a light beam from said recording head toward the recording medium while moving said recording head relative to the recording medium in a main scanning direction and in a sub-scanning direction orthogonal to said main scanning direction,in said step (b), said recording head moving through a distance corresponding to one N-th of a recording width of said recording head in said sub-scanning direction each time said recording head makes a single scan in said main scanning direction, to thereby make N repeated recordings at the same position on the recording medium, where N is an integer not less than two and different from the number of said light sources.