JPH0623931B2 - Scan position controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scanning position control device, and more particularly to a scanning position control device for controlling a scanning position of a scanning body by an encoder means.

[Prior Art] Conventionally, various recording devices such as an inkjet printer, a wire dot printer, or a typewriter are known. Most of these have a configuration in which a recording head is mounted on a carriage and one-way or reciprocal recording is performed by scanning the recording medium.

For scanning control in these apparatuses, that is, control of the recording position on the recording medium, a configuration is well known in which the carriage is driven by a pulse motor and the recording timing, that is, the recording position is determined according to the drive control pulse.

Further, a configuration is known in which the scanning position is controlled by an encoder. In this case, a detector such as a photocoupler is mounted on the carriage, and the position is detected by scanning an encoder plate provided with a large number of markers such as slits, and position control is performed based on this.

An example of this conventional encoder type position control is shown in FIGS. 1 (A) to 1 (C).

As shown in FIG. 1, the slit plate E has a large number of slits s.
Are arranged at a pitch SP, and these are scanned in the directions of arrows A and B by the photocouplers P ₁ and P ₂ provided on the carriage on which the recording head is mounted. In order to prevent the positional deviation of the slit width on the forward path and the backward path, and to surely return the carriage to the recording start position at the time of carriage return, the photocouplers P ₁ and ₂ are displaced in the traveling direction as shown in the drawing. It is attached. The detection outputs of the photocouplers P ₁ and P ₂ are out of phase with each other when the carriage advances in the direction of arrow A and when it advances in the direction of arrow B, as shown in FIGS. 1B and 1C, respectively. Therefore, by utilizing this, the slit count number can be discriminated between the forward pass and the backward pass, and the slit can be returned to a predetermined recording start position. As a result, carriage return is performed even in the middle of the recording line to perform the backward recording.

However, since the photocoupler is mounted on the carriage by the above method, unless the sliding backlash, dimensional accuracy, etc. of the carriage are strictly controlled, an error will occur in the count number of the slit when returning from the middle of the carriage recording line. , The next recording may be misaligned. In view of this point, if the sliding play of the carriage is reduced too much, the driving load will increase or the manufacturing cost will increase. Therefore, in the prior art, naturally there was a limit in reducing the pitch SP of the slits in order to increase the recording resolution and accuracy.

The above-mentioned drawbacks are not limited to the recording device and the like, but are common to the device for controlling the scanning position by using the encoder for image reading and the like.

[Objective] The present invention has been made in view of the above drawbacks of the related art. With a simple and inexpensive structure, the scanning accuracy can be improved even if the accuracy of the mechanism is somewhat poor, and high speed, high accuracy and An object of the present invention is to provide a scanning position control device capable of performing scanning control with a large degree of freedom.

[Examples] Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 2 is a perspective view showing the structure around the carriage of a recording apparatus that employs the scanning position control device of the present invention.

The carriage 1 is slidably supported by guide bars 7 and 8 provided on left and right frames 6. The carriage 1 is driven by the DC motor 4 via the belt 3 attached to the carriage 1, scans the recording paper on the platen 9, and records by the recording head 2. Any of various recording methods such as ink jet and wire dot can be used for the recording head 2, and recording control is performed via a cable 13.

A detection unit 20 is provided below the carriage 1 so as to project therefrom. The detection unit 20 is composed of two arms as shown in the drawing, and the photocouplers 10 and 11 are provided on the two arms. The slit plate 12 provided on the left and right frames 6 is fitted between the arms of the detection unit 20.
The slits provided on the slit plate 12 are scanned by the photocouplers 10 and 11 with the movement of.

The structure of the slit plate 12 as the encoder plate is shown in FIG. As shown in the figure, the slit plate 12
Has slits as two series of markers. Of these, the lower slits SL1 to SLn are relatively long openings that divide the recording area into some zones for recording control, and the slits SL1 to SLn are moved in the R direction or the L direction by the photocoupler 11. Scanned along.

Further, the upper slits S1 to Sn are provided in large numbers at equal pitches corresponding to recording positions (not shown), and the slits S1 to Sn are scanned by the upper photocoupler 10. However, among the slits S1 to Sn, one or a plurality of slits corresponding to the ends of the lower slits SL1 to SLn are thinned out. That is, the pitch is set to double at this thinned-out portion. Figure 3 (A)
Then, fictitious slits LS1 to LSn (not shown) which should originally exist at equal pitches are shown in this blank portion. The ends of the lower slits SL1 to SLn are formed so as to be within the width of the above-mentioned aerial slits LS1 to LSn in the left-right direction.

The slit plate shown above may be formed by punching a slit made of plastic such as polystyrene. Further, it goes without saying that a pattern may be printed on the transparent plastic plate to form the slit. Alternatively, the slit portion may not be translucent, but only this portion may be configured to be light-shielding. Further, the slit plate 1 in which slits are formed by a magnetic method or the like depending on the type of detector
2 may be used.

FIG. 3B shows the detection output when the slit plate 12 is scanned by the photocouplers 10 and 11. Fig. 3 (B)
The upper row shows the detection signal TP of the photocoupler 10, and the lower row shows the detection signal TR of the photocoupler 11. 3 (A) and 3 (B) show the slits and the detection pulses in a vertical relationship.

FIG. 4 shows the configuration of the control system of the recording apparatus of the present invention. In the figure, reference numeral 31 is a control device 31 using a microprocessor, to which a RAM (random access memory) 33 and a ROM (read only memory) 34 are connected for control operation. A control procedure, which will be described later, is mainly stored in the ROM 34 as a program, and is stored in the RAM 3
Recording data is stored in 3. A timer 32 is connected to the control device 31 for the control described later.
The timer 32 can also be configured as software. However, the thick signal lines in FIG. 4 are data buses for exchanging data.

The hardware mechanism is controlled by the controller 31 via the interface 35.

Here, in the recording mechanism, the DC motor 4 for driving the carriage scan, the driving unit 40 of the recording head 2, and the driving unit 42 for driving the platen 9 are simply shown as blocks. These are driven by drive circuits 37, 39, and 41 in accordance with the control signals output from the interface 35, respectively.

The interface 35 includes the photocouplers 10 and 1 described above.
The output of No. 1 is input through known amplifiers 10A and 10B, respectively. Here, the output signals TP and TR of the amplifiers 10A and 10B are shown as the photocoupler 10 and the photocoupler 11, respectively. Further, a switch 36 for manual control by the operator is connected to the interface 35.

Next, the operation of the above configuration will be described in detail.

The carriage 1 is driven by the DC motor 4 to scan left and right along the platen 9, and the scanning speed is a predetermined signal TP obtained by detecting the slits S1 to Sn of the slit plate 12 by the photocoupler 10. Counting is performed by the counting means. If the speed is faster than the reference value, the DC motor 4 is turned off, and if the speed is slower than the reference value, the DC motor 4 is turned on.

The driving unit 40 of the recording head 2 is driven according to the recording data in the RAM 33, and the driving timing is synchronized by the output signal TP of the same photocoupler 10,
Recording is performed at a predetermined position (dot) on the recording paper on the platen 9 corresponding to the positions of the slits S1 to Sn.

Recording is also performed at the positions of the imaginary slits LS1 to LSn of the slit plate 12, and the recording position is controlled by using the timer 32. For example, if recording is performed in the R direction from the left side in FIG. 3A and the slit S18 is detected by the output signal TR, the control device 34 starts the timer 32 here. When the timer 32 counts the time during which the carriage 1 moves from the slit S18 to the position of the imaginary slit LS by the predetermined speed of the carriage 1 controlled as described above, the control device 31 is connected via the signal line Tl in FIG. The device signal is output to. The timing control device 31 uses the interface 35 to connect the recording head 2
Drives the driving unit 40 of R to move R at the position of the imaginary slit LS2.
Recording is performed based on the recording data stored in the AM 33.

Return control of the carriage 1, in particular, a recording line ends within the scanning range of the carriage, and carriage return is performed from the middle of the scanning range for recording the next line. The midway return is the lower slit SL1 of the slit plate 12. ~ SLn
On the basis of the output signal TR obtained by scanning by the photocoupler 11. For example, when recording is advanced in the R direction of FIG. 3 (A) and the recording data of the row is completed at the recording position within the slit SL2, the carriage 1 is further advanced and the slit SL3 is moved. The DC motor 4 is inverted when the left end is detected by the output signal TR, and the carriage 1 is returned. In order to return to the predetermined recording line start position, the output signal TP indicating the number of slits S1 to Sn is not counted from the returned position to perform position control, but the upper slit is detected when the right end of the slit SL is detected. This is done by starting the counting of. That is, counting for returning from the slit S37 to the recording start position is started.

By such control, a backlash of the carriage 1 and a count error generated when the carriage 1 returns due to a mechanical operation error can be eliminated, and the position control of the next row can be reliably performed. In particular, when returning, the right side end portions of the lower slits SL1 to n of the slit plate 12 are detected and then the upper slits S1 to Sn are counted to perform the position device, so that an accurate return operation can be performed. Moreover, since the slits corresponding to the right end portions of the slits SL1 to SLn are thinned out as the aerial slits LS1 to LSn, even if the carriage 1 is slanted due to backlash or the like, the slit SL1 is formed.
The counting error of the upper slit, which is caused by the fact that the slits S1 to Sn can be detected or not detected at the right end portion of ~ SLn, can be completely removed, and the position control becomes more accurate. According to such a method, even if there is some play in the carriage or a mechanical operation error, or even if the slit pitch for controlling the upper recording position is made fine to improve the recording accuracy and resolution, There is no occurrence of misalignment of recording due to such a count error.

In the above embodiment, the configuration in which only one upper slit corresponding to the end of the lower slit is omitted is illustrated, but if a detection error occurs due to the accuracy of the carriage, a larger number of upper slits may be omitted. You may

Further, in the above embodiments, the upper slit is provided according to each recording position, but this does not necessarily have to match the actual recording resolution, and it should be configured to be an integral multiple of the recording resolution. Good.

Further, in the above embodiment, DC is used as the carriage driving means.
Although the motor is exemplified, it goes without saying that a pulse motor or the like may be used.

As described above, the carriage return can be performed for each zone indicated by the lower slit of the slit plate 12, and the recording speed can be increased. Moreover, as described above, high-quality recording can be performed by highly accurate recording position control based on accurate encoder slit count. Further, the present invention can be implemented with a slight change in hardware and software, which is useful for cost reduction.

The above-described technique of the present invention can be implemented regardless of various recording methods such as ink jet recording, heat sensitive recording, discharge breakdown recording and the like. Further, the present invention can of course be implemented in an impact recording device such as a daisy printer instead of dot recording, or a device that performs scanning for purposes other than recording such as image reading.

[Effect] As is clear from the above description, according to the present invention, in the scanning position control device for controlling the scanning position of the scanning body by the encoder means, the markers provided in the scanning region of the scanning body are counted. A counting unit, a first marker group that divides the scanning region of the scanning body into a plurality of zones, and a first marker group that prevents counting errors of the counting unit when the scanning body is reversed. At least one of the portions corresponding to the zone end portion is removed, and an encoder plate provided with a second marker group having an equal pitch determined corresponding to the scanning resolution of the scanning area, and the first and second encoder plates The encoder means is composed of first and second detectors for detecting the marker group, and the first marker group is used by the first detector when the scanning body is reversed. When the end of the zone is detected, the second detector detects the second marker group, and the counting means starts counting the second marker group to control the position of the scanning body. Since a structure including a control means for controlling the structure is adopted, even if the accuracy of the mechanism is slightly poor due to the simple and inexpensive structure, the scanning accuracy can be improved, the high speed,
It is possible to provide an excellent scanning position control device that can perform scanning control with high accuracy and a high degree of freedom.

[Brief description of drawings]

FIG. 1A is an explanatory view for explaining the configuration of a conventional scanning position control device, FIGS. 1B and 1C are diagrams for explaining a conventional scanning position control operation, and FIG. FIG. 3 is a perspective view of an embodiment of a recording apparatus adopting the scanning position control device of the present invention, FIG. 3 (A) is an explanatory view showing the structure of the slit plate in FIG. 2, and FIG. 3 (B) is 3A is a diagram showing the scanning output of the slit plate, and FIG. 4 is a block diagram showing the control system of the apparatus shown in FIG. 1 ... Carriage 10, 11 ... Photo coupler 12 ... Slit plate 31 ... Control device 32 ... Timer

Claims (1)

[Claims] 1. A scanning position control device for controlling a scanning position of a scanning body by an encoder means, a counting means for counting markers provided in a scanning region of the scanning body, and a scanning region of the scanning body in a plurality of zones. In order to prevent a counting error between the first marker group to be divided and the counting means when the scanning body is inverted, at least one of the first marker group is removed at a portion corresponding to the zone end portion. And an encoder plate provided with a second marker group having an equal pitch determined corresponding to the scanning resolution of the scanning region, and first and second encoder plates for detecting the first and second marker groups.
While the encoder means is configured from the detector of, when detecting the zone end of the first marker group by the first detector when the scanning body is inverted,
A control means is provided for detecting the second marker group by the second detector, starting counting of the second marker group by the counting means, and controlling the position of the scanning body. Characteristic scanning position control device.