JP2857283B2 - Image scanning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the rotation of a cylinder for recording image data sent from a data generator on a recording medium such as a photosensitive film fixed to the peripheral surface of the cylinder.
The present invention relates to an image scanning device that moves a recording head and the like.

[0002]

2. Description of the Related Art An outline of the structure and operation of an image scanning device used in a conventional output scanner will be described with reference to FIG. The image scanning device includes a cylinder rotating mechanism for rotating the cylinder 10 and a recording head moving mechanism for moving the recording head 12 in parallel with the central axis of the cylinder 10. The cylinder 10 is rotated at a constant speed by a cylinder motor 51 (the direction of this rotation is referred to as a main scanning direction).
The rotation angle is always detected by a rotary encoder 11 provided on the opposite side of the cylinder motor 51. The recording head 12 travels on a rail 52 provided parallel to the center axis of the cylinder 10 and is moved by a transverse motor (step motor) 13 via a ball screw 14 provided parallel to the rail 52 ( This direction is called the sub-scanning direction). As shown in FIG. 6, the recording head 12 usually has
A plurality of light emitting elements such as semiconductor lasers, LEDs, and the like, and recording elements 61 such as ink jet nozzles are provided in a line in the sub-scanning direction, and a plurality of scanning lines are recorded at one time by one rotation of the cylinder 10. It has become. Therefore, the recording head 12 intermittently moves in the sub-scanning direction in units of an amount corresponding to the pitch of the plurality of scanning lines in the sub-scanning direction (hereinafter, this is referred to as one movement unit).

The rotation of the cylinder 10 and the control of the movement of the recording head 12 are controlled by a control unit 18 provided with a microcomputer. In a conventional image scanning apparatus, the control of the movement of the recording head 12 is as follows. Was being done. A predetermined number (recording head 1)
When the image data Di (i = 1, 2, 3,...) Corresponding to the scanning lines of the number of the recording elements 61 provided in the second unit 2 are received, the control unit 18 causes the rotary encoder 11 to detect the origin of the cylinder 10. Wait to do. After the rotary encoder 11 detects the origin, the control unit 18 waits for the rotation of the cylinder 10 by a predetermined offset amount, and when the rotation position of the cylinder 10 reaches a predetermined recording start position, the recording head 12
Starts output of image data. Here, the control unit 1
8 does not detect whether or not the output of the image data Di has been completed. When the rotary encoder 11 next detects the origin, the control unit 18 sends the image data Di for the next predetermined number of scanning lines from the data generating device 19. Request to send +1 and receive it. Then, as in the previous cycle, the apparatus waits for the rotary encoder 11 to detect the next origin, and outputs image data Di + 1 after a predetermined offset after the detection of the origin.

[0004]

As described above, in the conventional image scanning apparatus, after the recording head 12 outputs the image data, the cylinder 10 is turned off while the image data is not output.
Rotate (this is called idle rotation). This is because the origin of the next rotary encoder 11 is detected (i.e., the cylinder 10) in order to confirm that the output of the current image data has ended without fail before accepting the next image data.
However, when the output area of the image data is sufficiently small, such idle rotation of the cylinder 10 is a waste of time.

The present invention has been made in order to solve such a problem, and when possible, can continuously output image data for each rotation without idling the cylinder. An image scanning device is provided.

[0006]

According to the present invention, there is provided an image scanning apparatus comprising: a recording medium fixed to a peripheral surface of a cylinder rotating in a main scanning direction which is a peripheral direction; An image scanning device for recording by a recording head that moves intermittently in units of one movement in a sub-scanning direction parallel to the central axis of (a), wherein a) the amount of image data in the main scanning direction sent from the data generation device From the time required to move the print head by one movement unit, it is determined whether or not the print head can move by one movement unit in the sub-scanning direction within the time when the print head during one rotation of the cylinder does not perform printing. Determining means, b) recording end detecting means for detecting that the recording of the image data in the main scanning direction has been completed, and c) recording by the recording end detecting means when the determining means determines that the image data can be moved. End characterized in that it comprises a immediate recording head movement control means for starting the movement of the first moving unit of the recording head after being detected.

[0007]

The output time of image data in the main scanning direction can be calculated from the amount of image data in the main scanning direction. Therefore, by subtracting the output time of the image data from the time required for one rotation of the cylinder, the time during which the cylinder rotates the non-recording portion (non-recording time) can be calculated. The determining means determines whether the recording head can complete the movement within the non-recording time by comparing the non-recording time with the time required for moving the recording head by one movement unit. When the recording head can be moved, the recording head starts moving immediately when the recording end detecting means detects that the output of the image data in the main scanning direction has been completed. Since the time required for moving the print head by one movement unit is shorter than the non-printing time, when the cylinder reaches the output start point of the scan data, the print head has already moved to the next position, and Scan data can be output immediately without performing unnecessary rotation.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The image scanning apparatus of the present embodiment is used for an output scanner for plate making, and as shown in FIG.
Rotary encoder 1 provided at one end of rotation shaft 0
1. Ball screw 1 arranged parallel to the axis of cylinder 10
4, a recording head 12 screwed to the ball screw 14, a transverse feed motor 13 for rotating the ball screw 14, and a control unit 28. The control unit 28 is mainly configured by a microcomputer 20, and further includes a flip-flop 21 responsive to an origin detection signal from the rotary encoder 11,
Receives the data from the current position counter 22 which counts the pulses generated for each predetermined minute angle, and the data from the data generator 19, separates the header data and the scan data (these will be described later), , A data reception interface (I / F) unit 27 provided between the data generator 19 and the scan data output unit 25, and counts the number of scan data sent to the recording head 12. And a step motor controller 26 for controlling a lateral feed motor (step motor) 26.

The operation of the image scanning apparatus according to the present embodiment having the above configuration at the time of outputting image data will be described with reference to the flowcharts of FIGS. First, the microcomputer 20 receives header data from the data generator 19 via the scan data output unit 25. The header data is data relating to information such as the size of an image to be output from now on, the offset of image recording on a recording medium, etc., and the image data in the main scanning direction (scanning data) is included in the image size information.
(The number of data in the main scanning direction). The microcomputer 20 extracts the value of the number of data in the main scanning direction from the header data (step S11),
The non-recording time t3 during the rotation is calculated (step S1).
2).

Here, the non-recording time t3 will be described. As shown in FIG. 4A, the entire circumference L of the cylinder 10
0, the recording medium 15 is wrapped around only a part L1, and the length L2 in the circumferential direction (main scanning direction) of the area (image recording area) 41 where an image is recorded is further reduced. Department. For this reason, the print head 12 actually outputs the scan data on the print medium 15 in FIG.
As shown in (b), the time t during which the cylinder 10 makes one rotation is t.
Only the part t2 (corresponding to L2) of 0 (corresponding to L0), and the recording head 12 does not output the scan data during the remaining time t3. This time t3 is the non-recording time. The time t0 required for one rotation of the cylinder 10 can be calculated from the rotation speed of the cylinder motor 51 for driving the cylinder 10 (see FIG. 5). It can be calculated from the diameter, the rotation speed thereof (the rotation speed of the cylinder motor 51), the number of data in the main scanning direction, and the pixel pitch of the recorded image in the main scanning direction. Therefore, the non-recording time t3 can be calculated as the difference (t0-t2).

Next, the microcomputer 20 determines the time t4 required for the recording head to move by one movement unit, the scanning line pitch of the recording image, the number of recording elements 61 of the recording head, and the Calculate from speed (step S
13). Then, it is determined whether or not the non-recording time t3 is longer than the horizontal feed time t4 of the recording head 12 (step S14). If the non-printing time t3 is longer, the print head 12 can complete the movement to the next position before the start of the output of the next scan data. The processing for this is shown in FIG.
This is performed after step S21 in FIG. However, if the time t4 required for the movement of the recording head 12 is longer than the non-recording time t3, the cylinder 10 must be idly rotated by one rotation, and the process proceeds to step S31 in FIG. 3B. .

First, the processing performed by the microcomputer 20 when t3> t4 will be described with reference to FIG. In this case, the microcomputer 20 first resets the flip-flop 21 (Step S21). When the rotary encoder 11 detects the origin of rotation of the cylinder 10 (Or in FIG. 4B), the flip-flop 21 is set, and the current position counter 22 starts counting (step S22). Thereafter, the microcomputer 20 constantly monitors the value of the current position counter 22, and determines whether or not the value of the current position counter 22 has become equal to the output start position count number (start position) (step S23). Here, the output start position count number is the count number of the rotary encoder 11 corresponding to the offset of the output start point (the angle between Or and St in FIG. 4B), and the offset amount is the header data. From the data generation device 19 as a part of When the value of the current position counter 22 becomes equal to the output start position count number, the microcomputer 20 sends a command to the scan data output unit 25 to start outputting the scan data. The scanning data output unit 25 sends the scanning data to the recording head 12 via the output counter 24, and the recording head 12 records an image on the recording medium 15 by each recording element 61 (step S).
24). During this time, the output counter 24 counts the number of scan data sent to the recording head 12, and the microcomputer 20 compares the count value with the number of data (predetermined number) in the main scanning direction (step S25). If the number of output data has not reached the predetermined number yet, the output of the scan data is continued (step S24).

When the number of output data reaches a predetermined number, the microcomputer 20 sends a command to the step motor controller 26, and
(Step S26)
At the same time, the process returns to the step S21 and the flip-flop 2
1 is reset and the detection of the origin Or of the next rotation is awaited. As described above, this routine (FIG. 3A) is executed only when the time t4 required for the horizontal movement of the recording head 12 in one movement unit is shorter than the non-recording time t3. At the time when the horizontal feed of the recording head 12 has been completed, the next output start point St has not yet reached the position of the recording head 12. Therefore, when the rotary encoder 11 detects the origin Or in step S22, it is the origin Or of the rotation immediately following the previously output rotation.
0 outputs the scan data continuously in the sub-scanning direction without performing idle rotation.

If it is determined in step S14 in FIG. 2 that the horizontal feed time t4 is longer than the non-recording time t3, the processing from step S31 in FIG. 3B is executed. Also in this case, at first, similar to the routine of FIG.
First, the flip-flop 21 is reset (step S
31) Then, the rotary encoder 11 detects the origin Or of the rotation of the cylinder 10, and the current position counter 22 starts counting (step S32). Then, it waits until the value of the current position counter 22 becomes equal to the predetermined output start position count number (start position) (step S33). The above is the same as the above routine. However, in this routine, when the value of the current position counter 22 reaches the output start position count number, the microcomputer 20 first resets the flip-flop 21 for detecting the origin, which will be described later (step S34). 25 to start outputting scan data (step S3).
5). The feature of this routine is that the recording head 12
Is not set to the end point of the output of the scan data, but to the point in time when the rotary encoder 11 detects the origin Or of the rotation of the cylinder 10 (step S36,
S37). Thereby, the microcomputer 20 outputs the output counter 24
Is released from the task of monitoring the value of, and other processing can be performed efficiently. The output of the scan data (step S35) automatically ends when the scan data output unit 25 runs out of scan data received from the data generator 19, but this naturally detects the origin Or in step S36. Exit before. After instructing the step motor controller 26 to feed the recording head 12 in the transverse direction, the microcomputer 20 returns to step S31 and returns to the origin O of the next rotation.
Wait for detection of r. For this reason, in this routine, the idle rotation of the cylinder 10 enters only one rotation during the output of the scan data in the main scanning direction. In the above embodiment, the microcomputer 20 executing the routine of FIG. 2 is used as the determination means, the output counter 24 and the microcomputer 20 checking the value in step S25 of FIG. And the microcomputer 20 performing the processing of S26 acts as a printhead movement control means.

In the above-described embodiment, an output counter 24 for counting the number of data actually output to the recording head 12 is provided to detect when the output of the scan data is completed in the routine of FIG. It was done by doing. However, the count value (end position count value) of the rotary encoder 11 at the time when the data output ends based on the number of data in the main scanning direction instead of the output counter 24 is calculated in advance, and the value of the current position counter 22 is set to the end position count. It may be determined that the output of the scan data has been completed when the value becomes equal to the value.

[0016]

According to the present invention, it is determined in advance whether or not the recording head can be moved within a non-recording time, and if it can be moved, the recording head is immediately moved when the output of the scan data is completed. Start moving. For this reason, the image data can be output quickly without causing unnecessary rotation of the cylinder during the output of the scan data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a plate making output scanner according to an embodiment of the present invention.

FIG. 2 is a flowchart of a first half of processing performed by a microcomputer of the plate making output scanner according to the embodiment;

FIG. 3 is a flowchart of the latter half of the processing performed by the microcomputer of the plate making output scanner according to the embodiment.

FIG. 4 is an explanatory diagram showing a relationship among a cylinder, a recording medium, and an output range.

FIG. 5 is a schematic configuration diagram of a plate making output scanner.

FIG. 6 is an explanatory diagram illustrating a state in which the recording head is recording an image on a recording medium.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Cylinder 11 ... Rotary encoder 12 ... Recording head 13 ... Horizontal feed motor 15 ... Recording medium 19 ... Data generation device 20 ... Microcomputer 21 ... Flip-flop 22 ... Current position counter 24 ... Output counter 25 ... Scan data output unit 28 ... Control Part 51: Motor for cylinder

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N 1/06 B41J 2/00-2/525 G03G 15/04

Claims (1)

(57) [Claims] An image data sent from a data generating device is transferred to a recording medium fixed on a peripheral surface of a cylinder rotating in a main scanning direction, which is a circumferential direction, by one movement unit in a sub-scanning direction parallel to a center axis of the cylinder. An image scanning device for recording by a recording head that moves intermittently every time, a) the amount of image data in the main scanning direction sent from the data generating device and the time required for moving the recording head by one movement unit Determining means for determining whether or not the recording head can move in the sub-scanning direction by one movement unit within a period during which the recording head during one rotation of the cylinder does not perform recording; and b) determining the image data in the main scanning direction. Recording end detecting means for detecting the end of recording; and c) when the judgment means judges that the recording is possible, immediately after the end of recording is detected by the recording end detecting means. An image scanning apparatus comprising: a recording head movement control unit that starts movement of a movement unit.