有没有办法使用 ESC 命令获取热敏打印机的状态？

Question

I am adding a method to the library escpos-coffee , which returns the status of a thermal printer, ie whether it is online/offline, whether the paper is ending or the paper is finished, or whether the cash drawer is open/closed.

I have added a method "showPrinterStatus" to the escpos-coffee library, which is based on the ESC c 3 command, which sends the command to the printer in byte form. The Method supposedly enables the Roll paper near end sensor, as well as the Roll paper end sensor. Furthermore, I have added another method "transmitStatus", based on the GS r command, which transmits the paper sensor status for n=1 and n=49, and the status of the cash drawer for n=2 and n=50. Here's the code:

 /**
     *
     * @param nSignal
     * @return
     * @throws IOException
     * Method decides whether the printer should return an output paper-end signal to a parallel interface or not
     * input 1,2 4,8 to enable, 0 to disable
     */

    public EscPos showPrinterStatus(int nSignal)  throws IOException {
        write(27);
        write('c');
        write('3');
        write(nSignal);
        return this;
    }

    /**
     *
     * @param n
     * @return
     * @throws IOException
     * returns the status of the printer, 1 or 49 returns paper sensor status, 2 or 50 returns drawer kick-out connector status
     */
    public EscPos transmitStatus(int n) throws IOException{
      write(29);
      write('r');
      return this;
    }

I am using Device Monitoring Studio, and excpected that there would be some visible communication. It looks like the showPrinterStatus Method is sending a signal to the thermal printer, but the transmitStatus method doesn't seem to cause any communication at all. Also, if I check the cash drawer status und leave the cash drawer open, there is no communication at all, and the request is simply queued. Once I push the cash drawer back in, it takes 5-10 minutes for the command to be executed by the printer, which is still in the queue all this time.

Is there something I am forgetting in my implementation, or is there a better way than Device Monitoring Studio, to display the printer status?

Answer 1

I had the same problem, but I was connected via the usb, try with the serial port and then read from it. Im not a java developer but here is my solution in python

from serial import Serial
serial = Serial('/dev/ttyUSB0', 115200, timeout=.03)
serial.write(b'\x10\x04\x01')
serial.read()

another approach is via the terminal(if you are using linux)

echo -n '\x10\x04\x01' > /dev/usb/lp0 #assuming lp0 is your printer 

cat /dev/usb/lp0 

it outputs the data in the buffer it does not print it on the paper

Answer 2

If you are using usb interface, you can try to use usb4java lib, then you can read bytes from the printer, for me it works on linux and show when door is open or paper end..., but i haven't tested it on windows...

    UsbEndpoint endpointIn = iface.getUsbEndpoint(endpointAddressIn);
    UsbPipe pipeIn = endpointIn.getUsbPipe();
    pipeIn.open();
    byte[] data = new byte[1024];
    int received;
    received = pipeIn.syncSubmit(data);
    pipeIn.close();

complete code is on github: Usb Printer Status