A printing unit for the rotogravure printing of a sheet or roll material, comprising: - a printing roller, defining a printing roller rotation axis and an outer printing roller lateral surface; - a pressure roller comprising a pressure roller body and a pressure roller sleeve which is fitted, or fittable, onto said pressure roller body, said pressure roller body defining a pressure roller rotation axis and a pressure roller body lateral surface; said pressure roller sleeve having a tubular shape defining an outer sleeve lateral surface and an inner sleeve lateral surface, said pressure roller sleeve comprising an outer layer made of elastomeric material delimited by said outer sleeve lateral surface; - pressing means for pressing said pressure roller against said printing roller, so that a rotation of said pressure roller and of said printing roller is capable of feeding the sheet or roll material interposed between said outer printing roller lateral surface and said outer sleeve lateral surface according to a feeding direction of the material; - an electrostatic printing aid apparatus associated with said pressure roller and configured to transmit electrostatic charges having a first electrical polarity to said outer lateral surface of said sleeve; - an electrostatic bar arranged at the outlet with respect to said pressure roller according to said feeding direction of the material, and adapted to face said material, wherein said electrostatic bar is configured to transmit electrostatic charges having a second electrical polarity opposite to the first electrical polarity to said material, so as to neutralize residual electric charges having the first electrical polarity, which remained associated with said material downstream of said pressure roller; - an anti-static outlet bar interposed between said pressure roller and said electrostatic bar, said anti-static outlet bar comprising at least one row of electrodes and an electrostatic discharge generator, said electrodes being adapted to face said sheet or roll material at the outlet with respect to said pressure roller, and adapted to be excited, by means of said electrostatic discharge generator, with electrostatic charges of alternating sign over time, so as to remove both the positive and the negative charges from the material at the outlet with respect to the pressure roller. - a printing roller, defining a printing roller rotation axis and an outer printing roller lateral surface; - a pressure roller comprising a pressure roller body and a pressure roller sleeve which is fitted, or fittable, onto said pressure roller body, said pressure roller body defining a pressure roller rotation axis and a pressure roller body lateral surface; said pressure roller sleeve having a tubular shape defining an outer sleeve lateral surface and an inner sleeve lateral surface, said pressure roller sleeve comprising an outer layer made of elastomeric material delimited by said outer sleeve lateral surface; - pressing means for pressing said pressure roller against said printing roller, so that a rotation of said pressure roller and of said printing roller is capable of feeding the sheet or roll material interposed between said outer printing roller lateral surface and said outer sleeve lateral surface according to a feeding direction of the material; - an electrostatic printing aid apparatus associated with said pressure roller and configured to transmit electrostatic charges having a first electrical polarity to said outer lateral surface of said sleeve; - an electrostatic bar arranged at the outlet with respect to said pressure roller according to said feeding direction of the material, and adapted to face said material, wherein said electrostatic bar is configured to transmit electrostatic charges having a second electrical polarity opposite to the first electrical polarity to said material, so as to neutralize residual electric charges having the first electrical polarity, which remained associated with said material downstream of said pressure roller; - an anti-static outlet bar interposed between said pressure roller and said electrostatic bar, said anti-static outlet bar comprising at least one row of electrodes and an electrostatic discharge generator, said electrodes being adapted to face said sheet or roll material at the outlet with respect to said pressure roller, and adapted to be excited, by means of said electrostatic discharge generator, with electrostatic charges of alternating sign over time, so as to remove both the positive and the negative charges from the material at the outlet with respect to the pressure roller.