JPS5882780A - Recording paper detector for printer - Google Patents

Abstract

PURPOSE:To simplify the treatment of host side by sending out a recording paper end signal corrected for the length to a print allowable position from a counting means on the basis of the final detection signal from a recording paper sensor provided at the stage behind the printing position. CONSTITUTION:A recording paper 1 is detected by a recording paper sensor 5 consisting of a photo diode and a photo transistor, provided at the stage A behind a printing position P. When recording paper exists, the detection signal X becomes ''1'', but when no recording paper exists, it becomes ''0''. As printing starts, a vertical spacing number corresponding to the length (l) from the position of the recording paper sensor 5 to the print allowable position B is preset in mu CPU11 functioning as a counter and a final detection signal X(=0) from the recording paper sensor 5 is put in the I of I/O port, whereupon the count is deducted and the count content is line-fed until 0 is reached. When the count content becomes ''0'', the output of the ''0'' of the I/O port becomes ''0'' and a recording paper end signal Z is sent through an OR gate 12 to the host side.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording paper presence/absence detection device for a printer.

FIG. 1 shows a schematic diagram related to recording paper in a general printer. Recording paper (1) is fed in the direction of the arrow by a platen (2) and a paper pail roller (3). Here, in printers such as inkjet printers, the print position P
If you print with the print head (4) when there is no recording paper (1) in the printer, the platen (2) will be smeared with ink, so the recording paper sensor (
5). In this case, the recording paper sensor (5) should be installed on the recording paper (1) at the most permissible position where K can be printed, and at the 9th position where it can be held down by the TTF paper pail roller (3) and guide (6).
Ideally, it should be installed in position B. However, due to restrictions such as the print head (4) and guide (6), the position, BK
In reality, the recording paper sensor (5) is installed at the position shown at A. As a result, the printing operation progresses, and when the end of the recording paper (1) reaches position A, it is detected by the recording paper sensor (5) and becomes K. However, the position B that should be detected is a distance of one length. Therefore, the detection output of the recording paper sensor (5) cannot be used as it is as a recording paper end signal, and this length of 1 minute must be counted by a μCPU, a counter, or the like. However, as shown in Figure 2, when connecting a printer (7) to a host (8) such as a t-computer, the printer (7)
This process is performed on both the host (8) side and the host (8) side, making the processing on the host (8) side complicated.

The present invention has been made in view of the above points, and even if a recording paper sensor is provided at a stage distant from the printing position, it is possible to obtain a recording paper end signal corresponding to an appropriate printing permissible position. It is an object of the present invention to provide a recording paper presence/absence detection device for a printer that can simplify processing on the host side.

A first embodiment of the present invention will be described based on FIGS. 3 to 7. 11 of FIG. 1 shall be used. first,
As shown in Fig. 3, the recording paper sensor (5) placed in the position is a reflective photosensor mainly consisting of a photodiode (9) and a phototransistor (g). 1), the phototransistor (2) of K is turned on and the detection signal X becomes H level, but when there is no recording paper (1), the transistor α1 is turned off? Then, the detection signal X becomes L level (see Figure 4).
. This detection signal X is transmitted to the printer's μCPU (11
)'s I10 boat has a large IK input. Here, this μCPU (11) acts as a counting means in which the number of line feeds corresponding to 1 minute of length is preset by a print signal, and the output from O of the Nirbort of μCPUQ@ is a detection signal. It is input to an OR gate (6) together with X. A recording paper end signal 2 is output from this OR gate C1e.

In such a configuration, when printing, the detection signal
Printing will not start unless the signal indicates an H level. Therefore,
When the recording paper (1) is detected by the recording paper sensor (5) when setting the recording paper (1), the recording paper (1) is moved to the vapor pail roller (3) t shown at position C in FIG. 1 based on auto-setting or auto-sheet feeding. automatically wrapped. When printing starts, the contents of the counter are first preset. When printing one line, the presence or absence of the recording paper (1) is checked depending on whether the detection signal is 1 or 0 as shown in Figure 7. I10 boat 0 to 1 (H
level) continues to be output. When the recording paper (1) runs out in the positioner, it is detected by the recording paper sensor (5), and when X becomes 0 as the end detection signal, the 9 counter is preset for each feed from the next line feed. 1 is subtracted from the contents. Then, when line feeding is performed until the counter contents become 0, the output of O of the VO port of the μCPU (11) becomes O. At this time, since the detection signal X has already been set to 0, the recording paper end signal 2 from the OR gate (2) also becomes 0, which means that there is no more paper.

In other words, although the recording paper sensor (5) is installed at a position farther from its original position, the length of 1 minute is μC.
When the end of the recording paper (1) reaches the printing permissible position B as shown in FIG. 1 (4) under the control of the PUQ1), a recording paper end signal 2 is generated by correcting the detection signal X by two minutes. will be output. Therefore, it is only necessary to notify the host side that the recording paper (1) has run out using this recording paper end signal 2, and there is no need for the host side to independently count and correct the length by 1 minute. The processing can be simplified.

Next, a second embodiment of the present invention will be described with reference to FIGS. 8 and 9. This embodiment uses a shift register (to) as a counting means. That is, the shift register (to) has n D flip-flops (14) to (1
4n) connected in series, the D terminal detection signal X of the first D flip-flop (141) is input, and the clock signal is input in common. The output xn of the final stage D flip-flop (14n) is used as the recording paper end signal Y.

In such a configuration, now, for example, length I is 2 inches and 61. Assuming that the minimum pinch for line feed is 1 inch, there are 12 lines, so the number of shift stages of the shift register (2) is set to 12, and a D flip-frog α♦ of n■12 values is used. Then, in the shift register (to), the p detection signal X is shifted by the shift pulse generated every time the pulse motor drives the line 7 (-) pulse, and becomes the recording paper end signal YFiH level.

However, when the end of the recording paper (1) passes the position person,
The detection signal X goes to the L level, but the recording paper end signal Y remains at the H level. After that, as the line feed continues, the D flip-flop α◆ is sequentially shifted to the L level, and when the line feed for 12 lines is performed, the output of the D flip-flop (14sx) is X11%, that is, the recording paper end signal Y also goes to L level, indicating that there is no paper left. When the recording paper end signal Y reaches the L level, the end of the recording paper (1) is located at the printing permissible position B, and the length of 7 minutes is corrected.

By the way, in the case of this embodiment, if the length between the printing permissible position B and the position C of the paper pail roller (3) in FIG. 1 is m, then the shift register (2 ) as shown in Figure 10, the shift register (
If connected to the latter stage of b), it is also possible to control when recording paper (1) is set. That is, when setting the recording paper (1), after detection by the recording paper sensor (5), the shift register (2)
) and shift register (c) by shift by pn + m' and send by length t + m, shift register (to)
This outputs a printable signal W from the output terminal.

In the present invention, as described above, the recording paper sensor is provided at a position downstream from the printing position, and the length up to the printing permissible position is calculated by the counting means based on the final power detection signal from the recording paper sensor. After correction, the paper end signal is finally output, so it can be processed on the printer side, and only this paper end signal needs to be sent to the host, simplifying the processing on the host side. It is something that can be done.

[Brief explanation of the drawing]

Figure 1 is a schematic side view of the printer's recording paper-related parts;
3 is a circuit diagram showing the first embodiment of the present invention, FIG. 4 is an explanatory diagram of its operation, FIG. 5 is a block diagram, seG is a timing chart, and FIG. 7 is a block diagram showing a conventional example. 8 is a circuit diagram showing a second embodiment of the present invention, FIG. 9 is a timing chart, and FIG. 10 is a block diagram showing a modification. 1... Recording paper, 2... Platen, 5... Recording paper sensor, 11... μCPU (counting means), 13...
・Shift register (counting means) ]J Figure (a) (&) 5Z Figure 1, 3

Claims (1)

[Claims] A recording paper sensor is provided that is located after the printing position on the platen and detects the end of the recording paper, and based on the end detection signal from this recording paper sensor, the recording paper for the length from the recording paper sensor position to the printing permissible position is installed. 1. A recording paper presence/absence detection device for a printer, characterized in that a counting means for counting feed is provided, and the output of the counting means is used as a recording paper end signal.