In this script, we will manipulate the gap between the ticks on the x axis:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker

X = np.linspace(-15, 15, 1024)
Y = np.sinc(X)

ax = plt.axes()
ax.xaxis.set_major_locator(ticker.MultipleLocator(5))
ax.xaxis.set_minor_locator(ticker.MultipleLocator(1))

plt.plot(X, Y, c = 'k')
plt.show()

Now, smaller ticks are seen between the usual ticks:

We forced the horizontal ticks to appear by steps of 5 units. Moreover, we also added small ticks, appearing by steps of 1 unit. To do so, we perform the following steps: