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TSC Printer Gap Sensor Not Working – Blackmark Solution

One of the most common problems with TSC brand thermal printers (TE244, TTP-244 Pro, TC200, DA220, etc.): the printer doesn't detect labels correctly. Labels skip, leave gaps, or the "Error" light flashes.

The root cause of this problem is usually sensor type incompatibility or lack of calibration.

Gap Sensor vs Blackmark: Understanding the Difference

TSC printers have two different label detection methods:

FeatureGap (Space) SensorBlackmark (Black Mark) Sensor
Working principleDetects transparent gap between labelsDetects black line on back of label
Sensor typeTransmissive (transparent – light transmission)Reflective (reflection from black line)
Label typeStandard labels (with gaps between them)Continuous roll, labels with black line on back
Use caseAddress labels, barcode labels, shipping labelsReceipts, label rolls, custom-cut labels
⚠️ Most Common Mistake

You're using gap labels but the printer is in blackmark mode. Or you're using blackmark labels but in gap mode. Result: printer can't find the label, skips, gives error.

Problem Identification: What Are the Symptoms?

Gap Sensor Issues

Blackmark Sensor Issues

Solution 1: Set the Sensor Type Correctly

Using TSC Diagnostic Tool

Download TSC Diagnostic Tool – you can download it from TSC support page

Run the program and select the printer (USB connected)

Go to "Printer Configuration" tab

Check the "Sensor Type" setting:

  • Normal label → Select Gap
  • Label with black line on back → Select Black Mark
  • Continuous paper (uninterrupted) → Select Continuous

Click "Set" or "Apply" button

Click "Calibrate" button to start calibration ✅

From the Printer (Using Buttons)

You can also adjust settings on TSC printers using button combinations:

Turn off the printer

Keep pressing the FEED button while turning on the printer

Release the button when LED starts flashing

Printer will perform automatic calibration – it will advance a few labels

Calibration is complete when LED stays solid ✅

💡 Tip

On TSC TE244 and TTP-244 Pro models, pressing the FEED button for 3 seconds starts calibration. Some models may require PAUSE + FEED combination – check your manual.

Solution 2: Physically Clean the Sensor

If calibration doesn't work, the sensor may be dirty:

Turn off the printer and unplug it

Open the cover and remove the label roll

Find the sensor area – usually at the bottom of the label path

Wipe the sensor with a cotton swab moistened with isopropyl alcohol (99%)

Wait for it to dry (1-2 minutes)

Insert label roll and perform calibration ✅

⚠️ Warning

Never touch the sensor with metal objects. A scratched sensor can be permanently damaged. Use only soft cotton swabs.

Solution 3: Check Sensor Position

On some TSC models, the gap sensor can be moved horizontally. The gap section of the label must be directly above the sensor.

ModelSensor PositionAdjustable?
TSC TE244CenterNo (fixed)
TSC TTP-244 ProCenterNo (fixed)
TSC TC200/300AdjustableYes – sliding mechanism
TSC DA220CenterNo (fixed)
💡 Label Positioning

On models with fixed sensors, make sure the label roll is centered. If the label roll shifts to one side, it will disrupt sensor reading.

TSC Printer Sensor Settings with TSPL Commands

For technical users: TSC printers support the TSPL command language. You can send commands directly via terminal or TSC Diagnostic Tool:

GAP 3 mm, 0 mm       // Gap sensor: 3mm gap
BLINE 3 mm, 0 mm     // Blackmark sensor: 3mm black line
DIRECTION 1,0        // Print direction
CLS                  // Clear screen
PRINT 1,1            // Print 1 copy

Model-Based Troubleshooting Guide

TSC TE244

TSC TTP-244 Pro

TSC DA220

Work with Your TSC Printer on macOS

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Frequently Asked Questions

Are gap and blackmark sensors the same on my TSC printer?

No. Gap sensor (transmissive) detects the gap between labels via light transmission. Blackmark sensor (reflective) detects the black line on the back of the label via reflection. They are different physical sensors, but some models have a single sensor that supports both modes.

How many labels are wasted during calibration?

Usually 2-4 labels. This is normal, the sensor is learning the label size and gap.

Can I use a TSC printer on macOS?

Yes. TSC printers support ZPL emulation. You can use them on macOS without installing a driver with LabelInn.

Does TSC Diagnostic Tool work on macOS?

No, it only works on Windows. For sensor settings on macOS, you can use LabelInn or send TSPL commands via terminal.