adaptronic_label-printer/old_code/PRINTER_CONFIGURATION.md

Thermal Printer Paper Size Configuration Guide

Problem

When printing labels, the PDF is generated correctly at 35mm x 25mm, but SumatraPDF prints them scaled to the printer's currently configured paper size. This results in incorrectly sized labels.

Root Cause

SumatraPDF's noscale mode preserves the PDF content but still uses the Windows printer's configured paper size. If the printer is set to A4, Letter, or continuous roll, the label will be scaled to that size.

Solution

Configure your thermal printer in Windows with the correct paper size (35mm x 25mm).

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Quick Setup

Step 1: Run Configuration Helper

powershell -ExecutionPolicy Bypass -File configure_printer_paper_size.ps1

Step 2: Manual Configuration

For Citizen CTS-310 Printers:

1. Open Control Panel → Devices and Printers
2. Right-click Citizen CTS-310II → Printing Preferences
3. Under Page Layout or Paper Settings:
   • Paper Size: Custom
   • Width: 35mm (1.38 inches)
   • Height: 25mm (0.98 inches)
   • Orientation: Landscape
4. Click Apply → OK

For Zebra ZD420/ZD421 Printers:

1. Open Zebra Setup Utility (ZSU) or Settings
2. Select your printer
3. Configure Media:
   • Media Type: Label Stock (NOT Continuous)
   • Label Width: 35mm
   • Label Height: 25mm
4. Configure Print Quality:
   • Darkness: 10-15
   • Print Speed: 4 ips
5. Send to Printer

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Critical Settings

⚠️ Media Type MUST be "Labels" or "Label Stock"

• Correct: Media Type = Labels (enables gap sensor)
• Wrong: Media Type = Continuous (prints entire roll, ignores gaps)

Paper Dimensions

• Width: 35mm
• Height: 25mm
• Orientation: Landscape (35mm is width, 25mm is height)

Print Quality (Thermal Printers)

• Darkness: 10-15 (NOT DPI - thermal printers use darkness control)
• Speed: Medium (4 ips recommended)
• Resolution: 203-300 DPI (hardware fixed, not configurable)

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Verification

Test Your Configuration:

1. Start the GUI:

   python label_printer_gui.py
   

2. Add test data to C:\Users\Public\Documents\check.txt:

   COM-001;ART-123;SN-001;0;1
   

3. Check the printed label:

   • ✅ Should be exactly 35mm x 25mm
   • ✅ Should fit the label perfectly (no scaling)
   • ✅ Should stop at label gap (not continue on roll)

If Labels are Wrong Size:

• Too large → Printer paper size is too big (check Windows printer settings)
• Too small → PDF might be generated incorrectly (check pdf_backup/ folder)
• Continuous printing → Media Type is set to "Continuous" instead of "Labels"

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Windows Custom Paper Size (Advanced)

If your printer driver doesn't have 35mm x 25mm preset:

Create Custom Form:

1. Open Control Panel → Devices and Printers
2. Select any printer → Print Server Properties (top menu)
3. Check "Create a new form"
4. Form name: Label35x25
5. Width: 3.50 cm (35mm)
6. Height: 2.50 cm (25mm)
7. Click Save Form
8. Now this form will be available in all printer settings

Assign Form to Printer:

1. Right-click your thermal printer → Printer Properties (not Preferences)
2. Device Settings tab
3. Form to Tray Assignment → Select Label35x25
4. Apply → OK

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Troubleshooting

Problem: Labels still wrong size after configuration

Solution:

• Restart the printer
• Restart the print spooler: net stop spooler && net start spooler
• Check if driver supports custom sizes (some old drivers don't)

Problem: Printer prints continuously without stopping

Solution:

• Change Media Type from "Continuous" to "Labels"
• Enable gap sensor in printer settings
• Calibrate media (Zebra: hold feed button 2 seconds)

Problem: Dotted or poor quality text

Solution:

• Increase darkness setting (10-15 recommended)
• Clean printhead
• Check ribbon (thermal transfer) or label quality

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File Format (check.txt)

ARTICLE;NR_ART;SERIAL;TEMPLATE_TYPE;COUNT

Examples:

• COM-001;ART-123;SN-001;0;1 = 1 OK label (green checkmark)
• COM-002;ART-456;SN-002;1;2 = 2 NOK labels (red text + "NOK")

Template Types:

• 0 = OK template (green checkmark, "OK" text)
• 1 = NOK template (red text, red checkmark, "NOK" text)

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Technical Details

PDF Generation Pipeline:

1. SVG Template (conf/label_template_*.svg)

   • Dimensions: width="35mm" height="25mm"
   • Variables: {Article}, {NrArt}, {Serial}

2. CairoSVG Conversion

   • Converts SVG → PDF at 300 DPI
   • Preserves SVG dimensions (35mm x 25mm)

3. SumatraPDF Printing

   • Uses -print-settings noscale (no scaling)
   • Sends PDF directly to printer
   • Uses printer's configured paper size

Why Paper Size Configuration is Critical:

SumatraPDF's noscale tells it "don't scale the PDF content", but the printer driver still needs to know what paper size to use. If the driver thinks it's printing on A4 paper, it will center the 35mm label on an A4 page.

By configuring the printer with 35mm x 25mm paper, the driver knows to feed labels of that size, and SumatraPDF will print the PDF content unscaled to match.

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Support

For issues:

1. Check printer configuration: configure_printer_paper_size.ps1
2. Verify PDF dimensions: Open file from pdf_backup/ in Adobe Reader
3. Check logs: logs/print_log_YYYYMMDD.csv
4. Test with Microsoft Print to PDF first (configure it for 35mm x 25mm)