How to send data between QThreads?

I have an event in one thread and need to invoke handler function in another. Usually I use function connect(), but in case of two threads I had an error:

QObject::connect: Cannot queue arguments of type 'QVector<unsigned char>'
(Make sure 'QVector<unsigned char>' is registered using qRegisterMetaType().)

I tried to use qRegisterMetaType(), but don't understood clearly how and where should I declare it. I wrote code sample, which just invoke execution in thread0 from thead1. I didn't include my attempts of using qRegisterMetaType() because they all failed =)

thread0.h:

#ifndef THREAD0_H
#define THREAD0_H

#include <QThread>
#include <QVector>

class thread0 : public QThread
{
    Q_OBJECT
public:
    thread0();
    ~thread0();

protected:
    void run() Q_DECL_OVERRIDE;

public slots:
    void printBuff(QVector<unsigned char> vec);
};

#endif // THREAD0_H

thread1.h:

#ifndef THREAD1_H
#define THREAD1_H

#include <QThread>
#include <QVector>

class thread1 : public QThread
{
    Q_OBJECT
public:
    thread1();
    ~thread1();

protected:
    void run() Q_DECL_OVERRIDE;

signals:
    void sendToPrint(QVector<unsigned char> vec);
};

#endif // THREAD1_H

main.cpp:

#include <QCoreApplication>
#include "thread0.h"
#include "thread1.h"
#include <QObject>
#include <QMetaType>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    thread0 *th0 = new thread0();
    thread1 *th1 = new thread1();

    QObject::connect(th1, &thread1::sendToPrint, th0, &thread0::printBuff);

    th0->start();
    th1->start();

    return a.exec();
}

and thread1.cpp:

#include "thread1.h"

thread1::thread1()
{

}

thread1::~thread1()
{

}

void thread1::run()
{
    QVector<unsigned char> vec = {0, 1, 2, 3};
    emit sendToPrint(vec);
}

P.S. If I use direct connection code works.

QObject::connect(th1, &thread1::sendToPrint, th0, &thread0::printBuff, Qt::DirectConnection);