Ink printing device and method for monitoring a chamber for airtightness

An ink printing device comprising:

• a printer housing in which is arranged a transport configured to transport a recording medium in the form of a web;
• a printer having configured to print to the recording medium;
• a dryer configured to dry and fix ink applied onto the recording medium, the dryer including:
• a dryer housing with two openings comprising an inlet slit and an outlet slit via which the recording medium is transported through the dryer,
• at least one heater and/or cooler configured to control a temperature of the dryer,
• at least one air supply configured to supply tempered air into the dryer housing, and
• at least one air exhaust configured to discharge operational exhaust air from the dryer housing;
• at least one temperature sensor arranged at a location outside of the dryer housing, in proximity to the at least one of the two openings of the dryer housing, the at least one temperature sensor being configured to measure a temperature at the location;
• and
• a controller communicatively coupled to the at least one temperature sensor and configured to:
• evaluate measured temperature values, compare a measured temperature value with at least one reference value, and generate an error signal based on the comparison,
• wherein at least one of the two openings has a tunnel-shaped collar, in the region of which the at least one temperature sensor is arranged,
• wherein the at least one temperature sensor comprises a first temperature sensor and a second temperature sensor arranged one after another in a flow direction with a predetermined clearance, and
• wherein the flow direction is a flow direction of a leakage air which is either created when a negative pressure is created in the dryer housing which results in an air flow from the printer housing into the dryer housing via the two openings or when operational exhaust air arrives as leakage air from the dryer housing into the printer housing via the two openings.