JPS6118802A - Position detecting apparatus - Google Patents

Abstract

PURPOSE:To detect the central position of a line width of a marking, by converting the first half of serial image signals in FN and the second half of it in RN. CONSTITUTION:A marking M moves with a movement of a sheet of recording paper. Movements of the marking M change consecutively the values of FN, RN, however, when the 24th bit of a line image sensor comes to be located just at the center of the line width of the marking M, or a little away to the rear of said center, the situations turn out to be as follows FN=RN or FN>RN, thus outputting a marking detecting signal. The center position of the marking M detects the timing accurately as it passes the 24th bit of the image sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a position detection device for image receiving paper such as a printer. The purpose is to perform printing and recording.

Configuration of conventional example and its problems Conventionally, in this type of position detection device, as a glorious element,
A single phototransistor or the like is used, the phototransistor receives reflected light from the marking on the image receiving paper, and the marking is detected only by turning on and off the output of the phototransistor. however,
With such conventional marking detection devices, it is difficult to detect markings with accurate positional accuracy in micron units.
C.

It could not be used in cases where three prints were to be accurately aligned on the receiving paper.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks of the prior art and to provide a position detection device that can accurately detect markings provided on recording paper in micron units.

Structure of the Invention A position detection device according to the present invention includes at least a line image sensor, a 2×n pit shift register, and a comparator for comparing a pair of n-bit outputs, and the serial image output of the line image sensor is compared with the serial image output of the line image sensor. The shift register inputs the first n bits of the serial image signal to an n-bit output F.
N, convert the latter n pits into n bit output RN,
The comparator compares FN and RN and generates a detection signal, allowing the making on the recording paper to be detected accurately in microns.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example in which the position detection device according to the present invention is applied to a thermal transfer printer.

A thermal head 20 has a plurality of heating elements 21 arranged in a line perpendicular to the drawing, and is movable to the position indicated by the dotted line 2A. 22 is an ink sheet coated with hot-melt ink; 23 is a take-up reel for the ink sheet 22;
4 is a supply roll for the ink sheet 22, and 27 is a platen roller, which is connected to a motor 32 by a one-way clutch. The ink sheet 22 and recording paper 25 are brought into close contact with each other and pressed against the thermal head 20.

10 drives the thermal head according to a recording signal;
This is a printing circuit that performs thermal transfer recording.

26 is a supply roll for the recording paper 25. A pressure roller 28 is designed to wrap the recording paper 25 around the platen roller 27, and these are the thermal heads 20. Ink/-t22. Ink sheet take-up reel 23. Ink sheet supply reel 24. Platen roller 27. Suppression roller 28. The printing circuit 10 constitutes a recording means, and the heating element 2 of the thermal head 2o is activated according to the recording signal.
1 is heated to melt and transfer the heat-melting ink of the ink sheet onto the recording paper 25 to perform recording. 30 is a capstan, and 40 is a pinch roller. The recording paper 25 is sandwiched between the capstan 30 and the pinch roller 31, and the capstan 3o is rotated by a motor 32 to cause the recording paper 25 to travel. , which constitutes a recording paper driving means. The thermal head 20 also serves as marking means for printing one or more markings on the recording paper 25 at regular intervals in the running direction of the recording paper 26 in order to detect the position of the recording paper 25. There is. Figure 3 is the first
This figure shows the state of a recorded image when recording is performed by the printer shown in the figure, and as shown in the figure, a marking M can be printed in the margin of the recording paper 26 other than the printing area E.

FIG. 4 shows a plan view of the ink sheet 22 used in the thermal transfer printer shown in FIG. 1. As shown in the figure, Y is yellow, M is magenta, and C is cyan. B is applied to a part of the edge of the sheet.
A plaque designated by L is coated with heat-melting ink. Using the part coated with black heat-melting ink shown in BL, ``Tsuna Marking M'' (not shown in Figure 3)
are printed by the thermal head 20.

Reference numeral 40 in FIG. 1 is a position detection device according to the present invention, which generates a detection pulse signal when detecting the center of the line width of a line-shaped marking M, and print timing control means 50. , position detection device 4 according to the present invention
The printing circuit 10 is controlled so that printing is started by the surfle head in synchronization with the marking detection signal of 0. Next, an embodiment of the position detection device according to the present invention will be described in detail with reference to FIGS. 9 and 6.

FIG. 5 is a block diagram showing a schematic configuration of an embodiment of a position detection device according to the present invention, and FIG. 6 is a diagram showing an operation timing chart of this embodiment. In FIG. 5, reference numeral 2 denotes a 64-bit lineage sensor, which is driven by a 64-pulse scanning signal SP. 1 is a magnifying lens, and marks M on the recording paper 25.
The marking M is enlarged and projected onto the line image sensor 2 by a magnifying lens 1 so that the line width direction of the marking M is in the main scanning direction of the line image sensor.
For example, the line width W = 120 μm width marking M is 10 μm.
The image is captured at m pitches and can be output from the line image sensor as a 12-bit serial image signal IM. It is a 3-digit, 2 x 8-bit shift register, which outputs the serial image signal of the line image sensor, outputs the first 8 bits as 8-bit output FN from QA2 to QH2, and outputs the latter 8 bits as QH1 to QA1.
It is designed to convert into an 8-bit output RN and output it.

4 is a comparator, which compares the 8-bit output RN and FN,
A detection signal CO8 is output when FN≧RN. Figure 7 shows the serial image signal Is of line image sensor 2 and the 8-bit output F of the shift register.
In other words, when a series of 7 real image signals is input to the shift register, the number of bits that go high on the 8-bit output FN will be the same as the number of bits that go high on the 8-bit output RN. When the number of bits exceeds the number of bits, FN≧RN and comparator 4
This is why it is designed to output the error determination signal CO8. Reference numeral 7 denotes a gate signal generator, which generates a gate signal GP at the 32nd pulse for the 64-pulse line image sensor scanning signal SP. It is ANDed with the signal GP and outputs Mo1, and the detection position is defined as the 24th bit on the line image sensor. Mo1 is input to an edge detection circuit 6 mainly composed of an inverter, and the edge detection circuit detects the rising edge of Mo1, and finally outputs a marking detection signal MO. Next, the marking detection process according to the embodiment of the present invention will be explained in more detail.1. FIG. 8 shows the positional relationship between the marking M having a line width of "W = 120/1 m width" in the example shown in FIG. 5, the image sensor, and the FN and RNO values at that time. is a − in the direction of the arrow in the figure as the recording paper moves.
Move to e.

I will do it. As the marking M moves, the values of FN and RN: change sequentially as shown in the figure.
When the 24th bit of the image sensor is located exactly at the center of the line width of marking M, or when it is located even slightly behind the center of the line width of marking M, FN=RN or FN)RN, and the marking detection signal Mo is output. That is, it is possible to accurately detect the timing at which the center position of the marking saw width passes the 24th bit of the image sensor. Note that the time it takes to scan a 64-bit line image sensor once is extremely fast compared to the moving speed of the recording paper with markings (
For example, a few MHz), the detection time delay due to scanning is not a problem at all. As explained above, the embodiment of the present invention shown in FIG. 5 makes it possible to accurately detect the timing at which the center of the line width of the marking M passes through a predetermined position of the line image sensor. That's why.

Next, the operation of the thermal transfer printer shown in FIG. 1 to which the embodiment of the present invention is applied will be explained in more detail. Note that FIG. 2 shows a timing chart of the operation of the printer shown in FIG. 1.

When a start button (not shown) is pressed, the device starts operating, and the motor 32 rotates at a predetermined speed to run the recording paper 25, which is sandwiched between the pinch roller 31 and the capstan 30, in the direction of arrow B. - As shown in FIG. 2, the printer 2o starts printing markings M in the margins other than the print area E, and prints a plurality of markings at predetermined intervals (FIG. 2a). At this time, the platen roller tti.

Since it is connected to the motor 32 via a one-way clutch, the platen roller is completely free.
It is pulled by the recording paper 25 and rotates.

At the same time, the position detection device 40 starts operating, and the marking M printed by the thermal head 21 is
After traveling the distance β shown in FIG. 3, as shown in FIG. 4Q detects marking M and generates a pulse. The printing timing control means 60 controls the printing circuit 10 so that the thermal head 2o starts printing the yellow image in synchronization with the detection signal Mo generated by the position detection device 40 (FIG. 2c), and , predetermined printing is performed from the detection of the first marking M until the detection of the next marking M, and this operation is sequentially repeated each time a marking M is detected, thereby completing the first printing of the yellow image. Further, the ink sheet 22 is sequentially wound up by an ink sheet winding roll 23. Next, the thermal head 20 is moved to the position indicated by the dotted line 2A, and the motor 32 is reversed. At this time, Inc.
・22 is stopped without scanning. The capstan 30 and the pinch roller 31 rotate in a direction opposite to that during printing, and cause the recording paper 25 to travel in a direction opposite to arrow B. At this time, the platen roller 27 is connected to the motor 32 via a one-way clutch, and moves the recording paper 25 along the arrow B.
Since the speed of the outer circumference of the platen roller is slightly faster than the running speed of the recording paper 25, the recording paper 25 sandwiched between the suppression roller 28 and the platen roller 27 is , always running in the direction opposite to arrow B, under tension. Note that the pressing force between the platen roller 27 and the suppression roller 28 is weak, so the recording paper 25 always slips between the platen roller 27 and the suppression roller 28, and the recording paper 25 always slips between the capstan 30 and the pinch roller 31. In between, there is no slippage at all, and the running speed of the recording paper 250 is always determined by the rotational speed of the capstan 30. After the recording paper 25 is run in the position before printing the marking M, the motor 32 is rotated normally again to run the recording paper 25 in the direction of arrow B. At the same time,
The position detecting device 40 starts operating and generates a detection signal MO when it detects the marking M, just like when printing a yellow image, and the timing control means 50 outputs a detection signal MO.
0, and the detection signal MO generated by the position detection device 40
The thermal head 20 starts printing a magenta image in synchronization with , and sequentially performs predetermined printing after detecting a marking M until detecting the next marking M.
The printing of the Kesian image after finishing the printing of the magenta image is also done.
Just like printing a magenta image, the position detecting means 40 detects the marking M and sequentially performs the printing in synchronization with the pulses generated.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention comprises at least a line image sensor, a 2×n-bit shift register, and a comparator for comparing a pair of n-bit outputs, and a serial image signal of the line image sensor. is input to the shift register, and the shift register converts the first n bits of the serial image signal into an n-bit output FN, the latter n bits into an n-bit output RN, and the comparator converts the first n bits into an n-bit output RN. This is to compare the RN and output a detection signal, and it is possible to accurately detect the center position of the line width of a marking made on recording paper or the like.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a thermal transfer printer to which an embodiment of the present invention is applied, FIG. 2 is a diagram showing an operation timing chart of the printer shown in FIG. 1, and FIG. 3 is a diagram showing the printer shown in FIG. FIG. 4 is a plan view of an ink sheet used in the printer shown in FIG. 1, FIG. 5 is a block diagram showing an outline of an embodiment of the present invention, and FIG. Operation timing chart of the embodiment of the present invention, seventh
The figure shows the relationship between the serial image signal and the output of the shift register in the embodiment of the present invention, and FIG. 8 is a diagram showing the process of detecting markings in the embodiment of the present invention. 40...Position detection device according to the present invention, 1...Magnifying lens, 2...Line image sensor, 3...
...Shift register, 4...Comparator, 5...
...Gate circuit, 6...Edge detection circuit, 7.
...Gate pulse generator. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure → Figure 3 Figure 6 320u/se 32pa/se Location Figure 7 Figure 8

Claims (5)

[Claims] (1) It consists of at least a line image sensor, a 2×n-bit shift register, and a comparator that compares a pair of n-bit signals, and inputs the serial image signal of the line image sensor to the shift register, Position detection in which the first n bits of the shift register are used as n-bit output FN, the latter n bits are used as n-bit output RN, and the comparator generates a detection signal by comparing FN and RN. Device. (2) When the total number of bits of the line image sensor is 2×m, m≧n (Claim No. 1)
The position detection device described in Section 1. (3) n-bit output FN output from shift register
is input to the comparator with the bit side corresponding to the leading side of the serial image signal as the LSB side, and the n-bit output RN is inputted to the comparator as the bit side corresponding to the leading side of the serial image signal as the MSB side, and FN≧RN The position detecting device according to claim 1 or 2, wherein the comparator generates a detection signal when . (4) A gate signal generator that generates a pulse signal at the m-th bit of the drive scanning pulse of the serial image sensor and a gate circuit are provided, and the pulse signal of the gate signal generator and the detection signal of the comparator are ANDed. The position detection device according to claim (1), (2), or (3), wherein the gate circuit outputs an output. (5) Claim no.
4) The position detection device described in section 4).