JPH02111156A - Scanning control method and scanner - Google Patents

Abstract

PURPOSE:To reduce scanning deviation (recording deviation, read deviation) in the main scanning direction by regulating the scanning period during forward or return movement of a scanning element according to a data of a preset scanning period corresponding to number of scanning times or number of times of passing of a reference position. CONSTITUTION:A scanning period table 24 storing a time interval of a scanning (recording) timing signal SST, that is, a data of a scanning period corresponding to a count SCNO of a counter 23 has a forward moving area and a return moving area, either area is selected by designating the scanning direction (forward or return movement) with a scanning direction signal CW or CCW and a scanning period SCYC optimum to the present main scanning position is outputted by applying address designation of an area selected by the count SCNO. The scanning period is designated to the data of the scanning period in both the cases of forward and return movement so as to minimize the scanning deviation (recording deviation) of the forward movement and the return movement for each scanning number of times.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a scanning device applied to recording or reading images, and more particularly to a scanning device that performs scanning while reciprocating a scanning element.

BACKGROUND OF THE INVENTION FIG. 5 is a schematic perspective view of the mechanism of a conventional scanning device of this type. This scanning device is applied to an image recording device, and while reciprocating the scanning element in the direction indicated by the arrow (main scanning direction), the recording paper 40 is sequentially scanned by the scanning element. This is to record n pixels lined up in the sub-scanning direction).

Main scanning for recording is performed by moving the scanning element, but sub-scanning is performed by intermittently feeding the recording paper 40 in the direction of arrow a. This intermittent feeding of the recording paper 4o is performed by driving a pair of feed rollers 42 arranged above and below by a slide and knob motor (not shown) capable of intermittent feeding.

Upper and lower feed roller bears 41. , 42, a guide shaft 43, a steady rest shaft 44, and a recording timing index (hereinafter referred to as index) 45 formed with a scale are provided in parallel to the direction indicated by the arrow. This index 45 includes first slits 46 on the left and right that indicate the start and end of recording, and one pixel (bit).
A large number of second slits 47 indicating each recording timing are each formed by a method such as etching. A carrier 48 is attached to the guide shaft 43 so as to be movable forward and backward.

This carrier 48 is driven by a motor (not shown) and reciprocates in the direction indicated by the arrow (main scanning direction) while being guided by the guide shaft 43 and steady rest shaft 44. Still in career 4
8 includes a recording head 49 as the above-mentioned scanning element and a first
A detector 5o and a second detector 51 are provided.

The first detector 50 reads the first slit 46 on the index 45 to detect the recording start and end timing, and the second detector 50 reads the second slit 47 and detects the recording timing for each pixel. This is to detect.

In such a configuration, while the carrier 48 is moved to the right (backward movement) with the recording paper 4o stationary,
A scanning (recording) timing signal is continuously applied to the drive circuit of the recording head 49, and the recording head 49 sequentially records n pixels in the sub-scanning direction as a scanning unit. When the recording by this backward movement is completed, the recording paper 4o is moved in the direction of arrow a.
After moving the carrier 48 by a predetermined width, while moving the carrier 48 in the left direction (returning movement), a scan timing signal is continuously applied to the drive section of the recording head 49 to perform recording by a predetermined width. When the recording by this backward movement is completed, the recording paper 4o is moved by a predetermined width, and recording by the backward movement is started.

Figure 6 is an explanatory diagram of this recording, where one backward movement is performed in m columns (main scanning direction) and Xn rows (sub scanning direction).
images are recorded. The generation time of the scanning timing signal during the backward movement or backward movement is controlled by checking the position of the carrier based on the read value of the index 45 by the first detector 5o and the second detector 51. be done.

Problems to be Solved by the Invention The scanning (recording) pitch of such a scanning device varies depending on the application, but when applied to the recording section of a facsimile machine, the scanning pitch is as small as 0125, for example, and highly accurate scanning timing control is required. is required. However, the high-density, high-precision index 45 that satisfies these requirements is difficult to manufacture and must be expensive, resulting in a problem in that the price of the entire scanning device increases.

It is also conceivable to generate the recording timing signal at constant time intervals while the carrier is moving, without controlling the generation time of the scanning timing signal by detecting a slit corresponding to the scanning pitch. In this case, there is no need to provide high-density slits in the indicator, so the indicator becomes inexpensive.

However, as shown in Fig. 7, a scanning (recording) shift occurs in the main scanning direction between the forward movement and the width movement, and the continuity of the boundary between the recorded area due to the forward movement and the recorded area due to the sub-movement is impaired. This can lead to severe deterioration in image quality. FIG. 8 is a graph in which scanning deviations measured with such an actual apparatus are plotted for each main scanning position.

Such scanning deviation in the main scanning direction is mainly caused by one shift of the carrier.
Due to imperfections in the drive mechanism. That is, since the moving speed of the carrier is not strictly uniform within the scanning range, even if the cycle of the scanning timing signal is maintained strictly constant, the scanning pitch will be irregular. This variation in scanning pitch is not so large when only one of forward movement and backward movement is considered. However, since the degree of variation in the moving speed of the carrier differs between the forward movement and the backward movement, the degree of variation in the scanning pinch naturally also occurs. As a result, variations in scanning pitch depending on each movement direction are emphasized in some areas, resulting in a recorded image that becomes extremely unnatural.

The present invention has been made in view of the above-mentioned problems, and is caused by scanning deviation in the main scanning direction (recording deviation, reading It is an object of the present invention to provide a scanning control method and a scanning device that can significantly reduce the amount of deviation (shift).

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides data on scanning cycles that are preset corresponding to the number of scans or the number of times the reference position is passed for each case of forward movement and backward movement of the scanning element. Accordingly, during forward or backward movement of the scanning element, the scanning period of the scanning element is adjusted according to the direction of movement and the number of scans from the start of movement or the number of times the reference position is passed. be.

If the movement mechanism of the active scanner is specified, the scanning deviation characteristics will be approximately constant and reproducible. Therefore, for example, while the scanning element is moving forward and backward, scanning is performed at regular intervals to record or read an image, and the scanning deviation is measured from the image. Then, from this measurement data, in order to minimize the scanning deviation during movement in each direction, the necessary scanning period is set for each number of scanning, or for each of the multiple reference positions set in advance. If you set it and adjust the scan period as described above according to that data,
The reciprocating movement of the scanning element enables high-quality image recording or image reading with small scanning deviation.

It is of course possible to set the scanning cycle data for each number of scans in units of one scan, but even if it is set in units of multiple scans, scanning deviation can be sufficiently reduced.

Even if the interval between the reference positions is made sufficiently larger than the scanning pitch, the scanning deviation can be sufficiently reduced, so that an inexpensive index for detecting the reference position can be used. Further, the intervals between the reference positions do not necessarily have to be constant, and the intervals between some reference positions may be wide, and the intervals between other reference positions may be narrow.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view of a mechanical part of a scanning device according to an embodiment of the present invention. This scanning device is applied to an image recording device. FIG. 2 is a schematic block diagram of the control section of this scanning device.

In FIG. 1, ``■'' is a recording paper, and 2 is a pair of feed rollers for conveying the recording paper 1. In FIG. By driving this feed roller pair 2 by a step motor (not shown), the recording paper 1 is held between the feed roller pair 2 and the arrow a
direction (sub-scanning direction). 3 and 4 are guide shafts arranged parallel to the arrow direction (main scanning direction), respectively;
It is a steady rest shaft.

5 is a carrier, which can move forward and backward in the direction of the arrow while being guided by the guide shaft 3. The steady rest shaft 4 is connected to the carrier 5
This was provided to suppress vibration during movement. This carrier 5 is driven by a motor 7 via a belt 6. 8°9 is a pulley.

The carrier 5 is provided with a recording head 11 which is a scanning element for recording scanning. When a scanning timing signal (recording timing signal) is generated, this recording head 11 drives n recording elements (for example, heating resistor elements) lined up in the sub-scanning direction all at once according to an image signal, and scans n pixels. (recording).

A carrier left position detector 12 and a carrier right position detector 13 are provided at the left and right ends of the guide shaft 3, so that movement of the carrier 5 toward the end of the guide shaft 3 can be detected.

In FIG. 2, reference numeral 21 denotes a scanning timing generation circuit that generates a scanning timing signal (recording timing signal) SST. This scanning timing signal 21 is transmitted to the recording head 11.
1 drive circuit 22 as a scanning (recording) start signal. Note that one drive circuit n is generally integrated into the recording nozzle 11. B is a counter for counting the scanning (recording) timing signal SST.

2.1 is a scan period in which data of the time interval of the scan (record) timing signal SST, that is, the scan period (time interval from one scan start time to the next scan start time) is stored in correspondence with the count value SNO of the counter 23. It's a table. This table 2.1 has an area for forward movement and an area for forward movement, and one area is selected by specifying the scanning direction (distinction between forward movement and backward movement) using scanning direction signals cw and ccw, and the count value By addressing the area selected by 5CNO, the optimum scanning cycle 5CYC is output for the current main scanning position.

This scanning period data specifies the scanning period for each forward movement and backward movement so that the scanning deviation (recording deviation) between the forward movement and the backward movement is minimized for each number of scans.

Specifically, for example, an image is recorded at a constant scanning cycle while moving the carrier 5 in the forward or backward movement direction, and the actual scanning (recording) deviation from the recorded image is calculated by a count value of 5CN.
It is measured in association with O (number of scans). Then, in the range where the scanning deviation increases to the plus side (to the right in the forward movement), the scanning period is determined to be smaller than the standard to cancel it out, and in the range where the scanning deviation increases to the negative side (to the left in the forward movement), the scan period is determined to be smaller than the standard. Conversely, set the scanning period larger than the standard.

Note that such recording deviations are mainly caused by the drive mechanism of the carrier 5, and have a fairly high reproducibility for each individual scanning device. Furthermore, since the scanning deviation generally varies relatively slowly, in practice, even if the scanning period is set in relatively coarse units, the scanning deviation can be sufficiently corrected. Therefore, as the count value 5CNO, the lower one or several bits of the counter value may be removed, and the remaining upper focus may be used as the count value 5CNO, and the scan period data may be set for each of a plurality of scans.

5 is a control circuit which receives a recording operation start signal ST,
Detection signal 5LFT of carrier left position detector 12, detection signal 5RIT1 of carrier right position detector 13 and scanning (
Recording) Timing signal SST is input. From this control circuit section, a scanning direction signal CW (forward movement), CCW (return movement), a clear signal CR1 for the counter field, a timer start signal TST for the scanning timing generation circuit 21,
is output. The scanning direction signals cw and ccw are supplied to the drive control circuit 26 of the motor 7.

The scan timing generation circuit 2] is a timer 27 that counts the elapsed time from the time when the timer start signal TST is generated.
and the count value TIM of this timer 27 and the scanning period 5CYC
, and when they match, turns on the scanning (recording) timing signal SST.

The operation of the scanning device configured as described above will be described below.

When the recording operation start signal ST is turned on, the control circuit section first turns on the scan direction signal CCW that specifies the backward movement direction, and causes the motor drive circuit 2G to rotate the motor 7 in the reverse direction. As a result, the carrier 5 moves to the left in FIG. When the carrier 5 reaches the left end of the guide shaft 3, the detection signal 5LFT of the carrier left position detector 12 is turned on.

When the control circuit 5 detects that the detection signal 5LFT is turned on, it turns off the scanning direction signal CCW and turns on the scanning direction signal CW for specifying the forward movement direction.

As a result, the ham motor drive circuit 26 rotates the motor 7 in the forward direction, so that the carrier 5 begins to move in the right direction.

Further, the forward movement area of the scan period table 24 is selected. At the same time, the control circuit 5 clears the counter B by turning on the clear signal CR. Now, the preparation for recording by forward movement is completed, and the control circuit 5 starts controlling the scanning by the recording head 11.

After clearing the counter n, the control circuit 5 turns on the timer start signal TST to reset the timer 27 and start counting. From the scan period table 24,
A scanning cycle of 5 cyc corresponding to the count value 5CNO (zero here) is output.

The comparison circuit of the scan timing generation circuit 21 turns on the scan timing signal SST when the scan period 5 cyc and the count value TIM of the timer nail match.

Thus, the recording head 11 is driven by the drive circuit n and performs the first scan (recording).

By turning on this first scan timing signal SST,
Counter O counts up by 1.

Still, the control circuit 5 turns on the timer start signal TST again. Therefore, scan timing signal SST is turned off. As a result, when a time period equal to the scanning period of 5 cyc outputted from the scanning period table 24 has elapsed, the comparator circuit reaches a match, turns on the scanning quimming signal SST again, and performs the second scanning.

The counter n counts up by 1. The control circuit 5 turns on the timer start signal TST again. Therefore, scan timing signal SST is turned off. When a time equal to the scanning period 5CYC has elapsed, the scanning timing signal SST is turned on again, and the third scanning is performed.

By repeating the same operation, according to the scan period data corresponding to the number of scans stored in advance in the scan period table 24,
Recording is performed by forward movement while the scanning period is appropriately adjusted according to the main scanning position.

When the carrier 5 reaches the right end of the guide shaft 3, the detection signal 5RIT of the carrier right position detector 13 is turned on.

When the control circuit 5 detects that the detection signal 5RIT is on, it turns off the scanning direction signal CW and clears the carrier 5 and the n. It also controls a step motor (not shown) for driving the feed roller pair 2 so as to feed the recording paper 1 by a predetermined amount.

When the feeding of the recording paper 1 is completed, the control circuit 5 turns on the scanning direction signal CCW and moves the carrier 5 to the left (backward movement).
start. Further, in the scanning period table 24, the area for backward movement is selected.

After this, the same control as in the case of forward movement is performed by the control circuit section, and an image is recorded. Then, when the carrier 5 reaches the left end of the guide shaft 3 and the detection signal 5LFT is turned on,
The control circuit 5 controls the end of the recording operation due to the backward movement, controls the feeding of the recording paper, and starts the control of the forward movement.

Images are recorded while the recording head 11 is moved back and forth in this way, but as mentioned above, the scanning period is appropriately adjusted according to the main scanning position, which eliminates the problem of recording deviation (main scanning directional scanning deviation) is significantly reduced, and high-quality recorded images can be obtained.

FIG. 3 is a schematic perspective view of a mechanical section of a scanning device according to another embodiment of the present invention, and FIG. 4 is a schematic block diagram of a control section of the same scanning device, in which reference numerals in FIG. 1 or 2 are used. The same reference numerals indicate equivalent parts.

This scanning device is also applied to an image recording device.

In FIG. 3, an indicator 30 for scanning timing control is provided along the moving path of the carrier 5. This index I is provided with reference position marks 31 at regular intervals, and the intervals are sufficiently thicker than the recording pitch (pixel interval in the main scanning direction).

The index I having such a coarse reference position mark can be manufactured at a much lower cost than a conventional high-precision index having a mark for each pixel.

The carrier 5 is provided with a mark reader 32 for setting a reference position mark 31 on the index 30.

In FIG. 4, 33 is a counter for counting the mark detection signal MD of the mark reader 32. In FIG.

The count value MCN0 of this counter 33 is the number of reference position marks 3] that have been detected during backward movement or backward movement, and is roughly measured in units of intervals between the reference position marks 31, which are sufficiently larger than the pixel interval. It means the main scanning position.

34 is a scanning period table corresponding to each scanning period table in FIG. However, in this example, index 3
In order to measure the scanning position based on the reference position mark 31 on 0, the scanning period table 34 is designed to recover data of a scanning period determined in advance so that the scanning deviation between the respective reference position marks 31 is minimized. Stored in separate areas for movement and return movement. Selection of an area is made by scanning direction signals cw and ccw, and addressing of the selected area is made by count value MCN0.

The scanning timing generation circuit 21 and control circuit Z5 are the same as those shown in FIG. Also ST, 5LFT.

The 5RIT, CW, and CCW signals are the same as the corresponding signals in FIG.

The operation of the scanning device configured as described above will be described below.

When the recording operation start signal ST is turned on, the control circuit 6 first turns on the scanning direction signal CCW, and the morph drive circuit 26 causes the motor 7 to rotate in reverse. When the carrier 5 moves leftward and reaches the left end of the guide shaft 3, the detection signal 5LFT of the carrier left position detector 12 turns on.

When the detection signal 5LFT is turned on, the control circuit 5 turns off the scanning direction signal CCW and turns on the scanning direction signal CW for specifying the backward movement direction. As a result, the motor 7 rotates in the forward direction and the carrier 5 begins to move in the right direction. Further, the area for backward movement in the scanning period table 34 is selected. At the same time, the control circuit 5 turns on the clear signal CR to clear the counter 3.
Clear 3. This completes the preparation for recording by backward movement.

After clearing the counter, the control circuit 5 resets the timer capital by turning on the timer start signal TST,
Start counting. From the scan period table 34, the scan period 5 corresponding to the count value 5CNO (zero here)
CYC is output.

When a time equal to this scanning cycle of 5 cyc has elapsed, the comparison circuit matches and the scanning timing signal SS is output.
Turn on T. The first scan (recording) by the recording head 11 starts.

By turning on this first scan timing signal SST,
The control circuit 25 turns on the timer start signal TST again. Therefore, the scan timing signal SST is turned off. From this, when a time equal to the scan period 5CYC output from the scan period table 34 has elapsed, the scan timing signal SST is turned on again and the second scan is performed.

In this way, scanning progresses sequentially, but the counter 33 is set to 1 each time a mark detection signal is output from the mark reader 32.
Count up step by step. Therefore, each time the reference position mark on the index 30 is detected, the scanning period is reset.

By repeating the above-described operations, recording is performed by backward movement while the scanning period is appropriately adjusted according to the main scanning position. When the carrier 5 reaches the right end of the guide shaft 3, the carrier right position detector 13 outputs a detection signal 5RIT.
turns on.

The control circuit 5 turns off the scanning direction signal CW to stop the carrier, and at the same time turns on the clear signal CR to turn on the counter 33.
Clear. In addition, a step motor (not shown) for driving the feed roller bearer 2 is used to feed the recording paper 1 by a predetermined amount.
control.

When the feeding of the recording paper 1 is completed, the control circuit 5 turns on the scanning direction signal CCW and moves the carrier 5 to the left (backward movement).
start. Further, in the scanning period table 34, the area for backward movement is selected.

Thereafter, the same control as in the case of backward movement is performed by the control circuit 5, and an image is recorded. Then, when the carrier 5 reaches the left end of the guide shaft 3 and the detection signal 5LFT is turned on,
The control circuit 5 controls the end of the recording operation by backward movement, controls the feeding of the recording paper, and starts controlling the forward movement.

Images are recorded while reciprocating the recording head 11 in this way, but as described above, the scanning period is appropriately adjusted depending on the number of times the reference position mark 31 on the index 30 is detected (the number of times it passes). Without using expensive high-precision indicators such as
A high-quality recorded image with small scanning deviation in the main scanning direction can be obtained.

The scanning device of each of the above embodiments can be applied to an image reading device by providing a reading head configured to optically read a document using a photoelectric conversion element in place of the recording head 11 as a scanning element 2 on the carrier 5. It is possible.

Effects of the Invention As is clear from the above description, the present invention provides scanning cycle data that is set in advance in accordance with the number of scans or the number of times the reference position is passed in each case of forward and backward movement of the scanning element. During the forward or backward movement of the scanner, the period of scanning by the scanner is adjusted according to the direction of movement and the number of scans from the start of movement or the number of times the reference position is passed, without using an index, or By using an inexpensive index, it is possible to record or read a high-quality image with little scanning deviation.

[Brief explanation of the drawing]

1 and 2 are respectively a schematic perspective view of a mechanism section and a schematic block diagram of a control section of a scanning device according to one embodiment of the present invention, and FIGS. 3 and 4 are respectively according to another embodiment of the present invention. A schematic perspective view of a mechanical section of a scanning device and a schematic block diagram of a control section. FIG. 5 is a schematic perspective view of a mechanical section of a conventional scanning device. FIG. 6 is an explanatory diagram of recording by reciprocating movement. FIG. 8, which is an explanatory diagram of scanning deviation (recording deviation) in the scanning direction, is a graph showing the relationship between scanning deviation (recording deviation) and scanning position. 1... Recording paper, 2... Feed roller pair, 3... Guide shaft, 5... Carrier, 6... Belt, 7...
Motor, 11... Recording head (scanner), 12...
Carrier left position detector, 13... Carrier right position detector, 21... Scanning timing generation circuit, n... Recording head drive circuit, n... Counter, 24... Scanning period table, 5 ...control circuit, 26...motor,
Drive circuit, moss...under tie, 28...comparison circuit, addition/
. . . index, 31 . . . reference position mark, 32 . . . mark reader, 33 . . . counter, 34 . Figure 1: Name of the prior agent: Patent attorney Shigetaka Awano and 1 other person Figure: 50 finger sense 7 so itta Figure 5: AI Otsuroku Tsume ＼, fO 1st experience = vessel ＼ 45 舊e銚15 Kuiguyuku? , Figure Figure

Claims (4)

[Claims] (1) During the forward movement or backward movement of the scanning element, according to scanning period data set in advance in accordance with the number of scans for each case of forward movement and backward movement of the scanning element,
1. A scanning control method in a scanning device for image recording or image reading, characterized in that the period of scanning by the scanning element is adjusted according to the direction of movement and the number of scannings from the start of movement. (2) In each case of the forward movement and backward movement of the scanning element, according to the data of the scanning period set in advance corresponding to the number of times the scanning element passes through a plurality of reference positions, the A scanning control method in a scanning device for image recording or image reading, characterized in that the period of scanning by the scanning element is adjusted depending on the direction of movement and the number of times the reference position is passed from the start of movement. (3) means for causing the scanning element to scan in response to a scanning timing signal; means for reciprocating the scanning element along the recording paper or document; and during forward movement or backward movement of the scanning element; means for counting the scanning timing signals generated during the forward movement of the scanning element, and storing data of a scanning period corresponding to the counted value of the counting means for each of the forward movement and backward movement, and means for outputting data of a scanning period corresponding to the movement direction and the count value of the counting means during intermediate or backward movement; and means for generating the scanning timing signal at a period determined according to the output data of this means. Scanning device for image recording or image reading, characterized in that: (4) means for causing the scanning element to scan in response to a scanning timing signal; means for reciprocating the scanning element along the recording paper or document; and means for moving the scanning element back and forth along the recording paper or document; means for detecting passage; means for counting detection signals provided by the detection means during forward or backward movement of the scanning element; means for storing data on a scanning period corresponding to the counted value, and outputting data on the scanning period corresponding to the moving direction and the counted value of the counting means during forward or backward movement of the scanning element; A scanning device for image recording or image reading, comprising means for generating the scanning timing signal at a period determined according to output data of the means.