Contrast Sensor (Colour Mark Sensor) for Packaging and Printing Machines
A contrast sensor – also called a colour mark sensor or registration mark sensor – detects printed eye-marks on film, foil and paper so that the machine cuts, seals or prints in exactly the right place. Voxintech supplies contrast sensors across India for form-fill-seal, flow-wrap, pouch-making and printing machines, with local technical support from Delhi NCR.
- Diffuse reflection detection – no separate reflector needed
- Selectable Light ON / Dark ON switching
- PNP open-collector output for direct PLC connection
- Quick teach-in setup on the machine
- Stable detection on glossy, matte and transparent films
- Compact, rugged housing for continuous packaging lines
Contrast Sensor Models
| Model | Detection | Output | Switching | Datasheet |
|---|---|---|---|---|
| VXT/CM-20PA | Diffuse reflection | PNP open collector | Light ON / Dark ON | Download PDF |
Contrast Sensor Applications
- Vertical and horizontal form-fill-seal (FFS) machines
- Flow-wrap and pillow-pack machines
- Pouch, sachet and bag-making machines
- Printing presses and registration control on flexible packaging lines
- Labelling and sleeving lines
How to Choose a Contrast Sensor
Check the contrast between the mark and its background, the web speed, the mounting distance and whether your PLC needs a PNP or NPN signal. If you are unsure, send us a sample of your printed film and we will recommend the right contrast sensor and settings.
Frequently Asked Questions
What is the difference between a contrast sensor and a colour sensor?
A contrast sensor detects the difference in brightness between a printed mark and the background, which makes it very fast and ideal for registration marks on moving film. A colour sensor identifies the actual colour of an object and is used for sorting or verification.
Is a colour mark sensor the same as a registration mark sensor?
Yes. Colour mark sensor, registration mark sensor, eye-mark sensor and contrast sensor are different names for the same type of sensor used on packaging and printing machines.
Can it detect marks on transparent or metallic film?
Yes. The sensor is designed for stable detection on glossy, matte and transparent films. For very reflective metallised film, mount it at a slight angle to avoid direct reflection.
Do you supply across India?
Yes. We supply contrast sensors from Delhi NCR to customers in all states. Call, WhatsApp or use the Get a Quote form for price and availability.