JPH0327462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a terminal breakage detection device for a sheet such as an ink donor film used in a thermal transfer recording device or the like.

In a thermal transfer recording device, an ink donor film coated with heat-melting or heat-sublimable solid ink is placed on recording paper (plain paper), and a heat pulse is selectively applied from the side of the ink donor film to melt the ink. Alternatively, information is recorded by sublimating it and transferring it to recording paper. The ink donor film is wound around a supply roll, and is used by being fed out in lengths necessary for recording. Since the supply roll is built into the apparatus, it is difficult for the operator to directly check the remaining amount of ink donor film. For this reason, it was not possible to detect that the ink donor film was running out during a recording operation, and a situation occurred in which recording suddenly became impossible. Therefore, a method has been proposed for detecting the end time of an ink donor film by providing a physically detectable mark near the end of the ink donor film, or at and near the end of the ink donor film.

For example, Utility Model Application Publication No. 1983-61824
No. 128400) discloses a device that is equipped with a roll paper having a cutout hole and an optical mark detection means section that optically detects the cutout hole to notify the user of the end of the roll paper. . Also, Utsukai Showa 52-
Publication No. 116234 (Utility Model Application No. 51-24243) discloses a device that detects seams as well as ends.
However, both of these were devices for detecting termination.

Incidentally, sheets such as ink donor films rarely break during use due to scratches or the like on the base paper. If the break occurs temporally before the detection of the end mark, it is naturally impossible to detect the end mark.

In such a case, the ink donor film becomes unable to feed the recording paper to the recording location due to the breakage, and the recording head is driven without contacting the recording paper. This not only makes it impossible to record an image, but also causes the problem that so-called dry printing adversely affects the life of the recording head. Of course, in a device that has a mechanism to detect the end mark with a transmission type photoelectric conversion element,
When the ink donor film breaks, the device detects this and warns the operator by performing a display operation similar to that used to indicate when the ink donor film is finished. However, in response to this warning display, the operator usually thinks that it is almost time to replace the ink donor film, and often continues recording in order to obtain the required number of recorded images. In this case, the same problem as described above occurred.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a sheet end breakage detection device that can distinguish and detect the end and breakage of a sheet.

In the present invention, there is provided a mark for detecting the end of a sheet provided at a distance from the end of the sheet, a sensor disposed in the supply path of the sheet supplied from the sheet supply means for detecting the absence of a sheet and detecting the mark, and a sensor based on the sensor. a signal output means for inverting and outputting an output signal both when detecting a sheet and when detecting a mark;
If the output of the signal output means is reversed and then returns to its original state within a predetermined time, it is determined that the sheet is at its end, and if the output does not return to its original state, it is determined that the sheet is broken. The above object is achieved by providing a determination means in a sheet end breakage detection device.

The present invention will be explained in detail with reference to Examples below.

FIG. 1 shows the vicinity of the end of a first type of ink donor film used in the end breakage detection device of this embodiment. On one side of the ink donor film 1, there is a non-recordable area 1A near the end.
Solid ink is uniformly applied except for. Recordable area 1 coated with solid ink
At the right end of B, there is _an electrical
An end mark 3 of a predetermined width that can be detected magnetically or optically is provided. When the remaining amount of the ink donor film becomes small as the ink donor film is used, the portion with the end mark 3 is unwound from the supply roll and detected by a detection means provided near the supply roll.

That is, this detection means inverts the logic of its detection output at the leading end of the end mark 3, and restores the logic of its detection output to the original logic at the rear end of the end mark 3 having a predetermined width. Through this detection operation, the thermal transfer recording apparatus indicates the end time of the ink donor film 1. At this point, in addition to the length from the detection means to the recording section, from the aforementioned end mark 3 to the boundary line 2.
Since the length L ₁ up to the end of the ink donor film 1 remains unused, the ink donor film 1 has enough room to record on several sheets of recording paper. Therefore, even after the display operation has been performed, the operator can obtain the required number of recorded images before replacing the ink donor film.

On the other hand, when the first type of ink donor film 1 is broken, the above-mentioned detection means inverts the logic of its detection output due to the breakage, and thereafter maintains that state. This detection operation determines whether the ink donor film 1 is broken.

FIG. 2 shows the vicinity of the end of the second type of ink donor film used in this example. At the right end of the recordable area 5B of the ink donor film 5, which is spaced a predetermined length _L2 from the boundary line 6 with the unrecordable area 5A, seven end marks 7 from which solid ink has been removed are indicated by arrows 8. They are arranged in a line in the longitudinal direction. In this embodiment, the predetermined length _L2 is set to 1 m. End mark 7 is a rectangular mark with a width of 5 mm in the direction of arrow 8 and a length of 10 mm in the direction perpendicular to this (width direction).
Arranged at mm intervals.

FIG. 3 shows a thermal transfer recording apparatus that uses the above-described first and second types of ink donor films 1 and 5 and is capable of distinguishing and detecting the termination and breakage of the ink donor films 1 and 5. For the sake of convenience, the explanation will proceed assuming that the second type of ink donor film 5 is used.

In this device, the ink donor film 5 is unwound from a supply roll 9 with its longitudinal direction aligned with the sub-scanning direction, passes through a detection section A and a recording section B in order, and then is wound onto a take-up roll. It's summery. The detection unit A includes a light source 12 that irradiates the side end of the ink donor film 5 on which the solid ink is applied, and a photo sensor 13 that is disposed at a position opposite to this with the ink donor film 5 interposed therebetween. The output of the photo sensor 13 is led to a detection circuit to individually detect the end and breakage of the ink donor film 5. The recording section B also includes a thermal head 14 that applies a heat pulse to the ink donor film 5, a back roller 15 that presses the ink donor film 5 against the thermal head 14, and a back roller 15 that drives the back roller 15 to transport the ink donor film 5. drive roller 16. In the recording section B, the recording paper 19 is fed by a pair of feed rollers 17 and 18 from a supply tray (not shown).
The thermal head 1 is sandwiched between the ink donor film 5 and the circumferential surface of the back roller 15.
4 and the cross roller 15. At this time, the melted or sublimated ink is transferred to the recording paper 19 according to the image information to perform thermal recording. After recording, the recording paper 19 passes between the back roller 15 and the drive roller 16, and then moves in the common tangential direction of the rollers 15 and 16 (direction of arrow 20) due to its own strength, and reaches the ink donor. It is separated from the film 5 and discharged onto a paper discharge tray (not shown).

Figure 4 shows the photo sensor 13 placed in the detection section.
The ink donor film 5 is
This figure represents a detection circuit that can distinguish between termination and breakage. This circuit is applied to the second type of ink donor film 5, and includes a ternary counter 22 that counts the number of rising edges of a signal input to a signal input terminal 21.
A flip-flop circuit 23 is set by the output of the carry signal from the ternary counter 22 and detects the end of the ink donor film, and a break detection circuit 24 detects breakage by a signal input to the signal input terminal 21. It is composed of. 3
The carry signal output from the decimal counter 22 is input to the input terminal 23S on the set side of the flip-flop circuit, and is input to the reset terminal R of the ternary counter and the reset terminal 23R on the reset side of the flip-flop circuit. , a reset signal 25 which changes to the H (high) level logic state is supplied by the operator's reset operation. In this detection circuit, a termination detection signal 23C is output from the positive logic output terminal Q of the positive logic output terminal 23Q and the negative logic output terminal 23 of the flip-flop circuit 23,
A break detection signal 2 is output from the output side of the break detection circuit 24.
4D is now being output.

FIG. 5 shows the waveform of the signal supplied from the photo sensor to the signal input terminal of the detection circuit. The photo sensor 13 shown in FIG. 3 detects the light beam emitted from the light source 12 when the ink donor film 5 has not reached its replacement time and is being transported normally without being broken. I can't. Therefore, in this case, the detection signal 26 which logically becomes H level at the time of detection is set as shown in FIG.
As shown in the figure, the output continues in a logical L (low) level state. Also, ink donor film 5
When the end mark 7 reaches its replacement time without causing any breakage, the photo sensor 13 intermittently detects the light beam that has passed through the end mark 7, and the detection signal 26 intermittently changes to H level as shown in FIG. 5b. Output a signal. Furthermore, if the ink donor film 5 breaks before it reaches its replacement time, the photo sensor 13 intermittently outputs an H level signal as a detection signal 26 as shown in FIG. output.

The operation of the detection circuit when each of these types of detection signals 26 is individually input to the detection circuit will be described next. FIG. 6a shows the temporal change in the signal supplied to the detection circuit from just before the end mark of the ink donor film reaches the detection section until it passes through the detection section. In this figure, before time _t1 , the ink donor film 5 (FIG. 2) has not yet reached its replacement time. The detection signal 26 inputted to the signal input terminal 21 at this time is an L level signal shown in FIG. 5a. The detection signal 26 is 3
The signal is supplied to both the advance counter 22 and the breakage detection circuit 24. The ternary counter 22 does not perform a counting operation in this state, and the input terminal 23S on the set side of the flip-flop circuit, which receives the H level carry signal, is maintained at the L level (sixth
Figure b). The flip-flop circuit 23 is composed of first and second NOR gates 23A and 23B whose output side is connected to the input side of the other logic element in a cross-over manner. In this state where the detection signal 26 is held at L level, the output terminal 23 connected to the output side of the first NOR gate 23A is at H level.
The output terminal Q connected to the output side of the second NOR gate 23B is held at the L level. At this time, the end detection signal 23C is held at the L level, and the subsequent circuit (not shown) to which this signal is input does not perform a warning display operation for detecting the rear end.

On the other hand, when the detection signal 26 held at the L level shown in FIG. Keep at potential. As a result, the signal input to the second inverter 24C is held at H level, and the break detection signal 24D appearing at its output side is held at L level. At this time, a subsequent circuit (not shown) to which this signal 24D is input does not perform control operations such as when the recording apparatus is stopped in an emergency due to breakage detection.

Now, the conveyance of the ink donor film 5 progresses without any trouble, and at time _t1, the end mark 7 is reached at the earliest point.
Suppose that the signal reaches the detection part A. From this time _t1 , the detection signal 26 changes to the pulse waveform shown in FIG. 5b, and the ternary counter 22 counts this every time the detection signal 26 changes to H level. At time t ₂ (FIG. 6a) when the photo sensor 13 detects the third end mark 7, the ternary counter 22
supplies an H level carry signal (FIG. 6b) to the input terminal 23S of the flip-flop circuit 23.
As a result, the flip-flop circuit 23 is set, and an H level termination detection signal 23C (FIG. 6d) is output from its output terminal Q. As a result, the subsequent circuit described above displays a warning indicating that the time for replacing the ink donor film 5 is approaching.
The operator does not need to immediately stop the recording apparatus when this warning is displayed, and can continue recording by the number of sheets of recording paper corresponding to a length of 1 m. After replacing the ink donor film, the operator presses a recovery button (not shown).
As a result, the reset signal 25 ( _sixth
(c) is supplied to the reset terminal 23R, and the flip-flop circuit 23 is reset.

On the other hand, when the detection signal 26 shown in FIG. 5B arrives at the termination detection circuit 24 from time _t1 , the output of the first inverter 24A periodically repeats the H level and L level states in response. however
Since the capacitor of the RC circuit 24B is discharged relatively slowly, the potential on the input side of the second inverter 24C (Fig. 6e) repeats a slight decrease periodically from, for example, 5V, Maintain level state. Therefore, the break detection signal 24D (sixth
The circuit shown in FIG. f) is held at the L level, and the subsequent circuit does not perform the above-mentioned control operation based on breakage detection.

On the other hand, suppose that the ink donor film 5 breaks at a time before the detection section A detects the end mark 7. As shown in FIG. 7a, the photo sensor 13 changes the detection signal 26 to H level at time _t4 when it detects this breakage. As a result, the output of the first inverter 24A of the breakage detection circuit changes intermittently to the L level, and the capacitor of the RC circuit 24B is discharged. As a result, the potential appearing on the input side of the second inverter 24C (Fig. 7b) gradually decreases from, for example, 5V, and at time _t5 , when the potential has decreased to a predetermined potential close to 0V, the potential is output from the second inverter 24C. rupture detection signal 24
D (FIG. 7c) changes from L level to H level. Subsequent circuitry thereby performs necessary control operations such as emergency stopping of the recording device. Note that if the ink donor film 5 is broken, the ternary counter 22 stops its counting operation when it counts one rising edge of the detection signal 26. Therefore, in this case, the flip-flop circuit 23 is not set and the H level termination detection signal 23C is not output.

In this way, according to the present invention, by detecting the mark provided on the sheet, both the end of the sheet and the break can be detected with one sensor, so it is possible to detect the end of the sheet and the break with a simple configuration. It has the effect of being able to distinguish between

In the embodiment, the end mark detection section is provided between the recording section and the supply roll, but it is of course possible to arrange it at other locations where the ink donor film is transported. In addition, in the embodiment, the distance L ₂ between the end mark and the unrecordable area was set to 1 m, but due to the relationship with the location where the end mark detection unit is installed, or when recording needs to be continued after the end mark is detected. Of course, it may be set to a different value depending on the number of sheets of paper. Further, in the embodiment, seven end marks are provided, and the end is detected when the third mark is counted by the counter. In general, it is considered preferable that the number of counts until the counter generates a carry for the number of end marks is based on equation (1).

Number of counts = (number of end marks - 1)/2
...(1) This is the case when the recording operation ends in the middle of counting end marks and the power to the device is turned off before the time to replace the ink donor film is displayed.
This is to ensure the end detection operation at the time of the next recording operation. The reason why the counter counts two or more marks is to prevent malfunctions due to noise. However, it goes without saying that the number of end marks and the count value of the counter can be set in any manner depending on the circuit configuration.

Further, in the embodiment, the end mark 7 is not provided within a predetermined length _L2 from the end of the recordable area 5B of the ink donor film 5. This is because there is generally no need for this, but the end mark 7
may be provided. By providing the end mark 7 up to or just before the end of the recordable area 5B, the end of the ink donor film 5 can be detected more stably. Further, the number of marks is continuously counted, and when a count value determined in relation to the size of a recorded image is reached, a replacement time can be displayed, and the ink donor film 5 can be used without wasting it.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention, and FIG. 1 shows the first embodiment used in this embodiment.
FIG. 2 is a plan view showing the vicinity of the end of a second type of ink donor film used in this embodiment, and FIG. A schematic configuration diagram of a thermal transfer recording device using film,
Figure 4 is a block diagram of a detection circuit that distinguishes and detects the end and breakage of the ink donor film, Figure 5 is a waveform diagram showing various waveforms of detection signals input to the detection circuit, and Figure 6 is a detection circuit. Various waveform diagrams for explaining the operation of the circuit to detect termination. FIG. 7 is various waveform diagrams for explaining the operation of the detection circuit for detecting a break. 5... Ink donor film, 7... End mark, 9... Supply roll, A... Detection section, 12...
...Light source, 13... Photo sensor, B... Recording section.

Claims (1)

[Scope of Claims] 1. A mark for detecting the end of a sheet provided at a distance from the end of the sheet, and a sensor disposed in the supply path of the sheet supplied from the sheet supply means for detecting the absence of a sheet and detecting the mark. , a signal output means that inverts and outputs an output signal both when the sensor detects a sheet absence and when a mark is detected, and when a change occurs in which the output of the signal output means returns to the original state within a predetermined time after being inverted; An apparatus for detecting a terminal end breakage of a sheet, comprising determining means for determining that the sheet is at its end, and determining that the sheet is broken if no change to return to its original state occurs.