Wider use of fast colour sensing
Original article date: September 1998
MTE Turck has introduced the R55 colour mark sensor for print verification label detection and web cutoff registration.
The Banner R55 colour mark sensor operating at extraordinary speeds of up to 10 000 operations per second is designed for printing presses and all types of labelling and sensing registration marks on packaging material. However its versatility opens up a much wider range of industrial applications.
The electronic design includes a solid-state emitter and receiver that allows the sort of colour mark resolution once only possible with incandescent systems. The R55 solid state light source can detect all colours found in contemporary print jobs even on extremely low contrast mark such as 20% yellow ink on newsprint.
The R55 has a response time of only 50us and can therefore fulfil the fastest requirements for users with high-speed production lines and web offset presses. The speed allows smaller colour marks to achieve the required throughput. In some cases colour marks can be eliminated using an “eye spot” on the package instead. It also includes a built-in 50ms delay and one-shot logic to allow an interface with slower input devices such as PLCs.
An advanced LED moving bar graph display indicates the contrast level between the colour mark and the background. It also indicates the sensor switch point making setup fast and easy. The sensitivity can be adjusted using a 15-turn knob. It works for all applications without the need to switch between multi-coloured LEDs. But when scanning difficult colour combinations new high power green LEDs are used which give a greater range of sensing contrast compared with red or blue.
The R55 has high tolerance to web flutter or other situations where there is a slight variation in the target distance. This is achieved by a focal point of 10mm and a depth of field of +/-3mm. The built-in analogue output enables the R55 to become a sensitive instrument that can measure surface brightness and texture consistency and perform colour recognition and surface mapping.
The R55 is designed to withstand impact and severe environmental conditions. It is also leak-proof and meets IP67 and NEMA6 standards. Rugged input and output circuitry prevents damage from high voltage transients or reverse polarity and provides noise interference immunity. Outputs are protected against stray pulses at switch-on as well as continuous overload at short circuits.
- MTE Turck
- George Perkins
- 01702 525186
September 1998