diff --git a/erpnext/accounts/Print Format/SalesInvoice/SalesInvoice.json b/erpnext/accounts/Print Format/SalesInvoice/SalesInvoice.json
deleted file mode 100644
index d8642b1..0000000
--- a/erpnext/accounts/Print Format/SalesInvoice/SalesInvoice.json
+++ /dev/null
@@ -1,13 +0,0 @@
-{
- "creation": "2013-03-21 15:24:28", 
- "doc_type": "Sales Invoice", 
- "docstatus": 0, 
- "doctype": "Print Format", 
- "idx": 1, 
- "modified": "2014-05-13 16:07:19.310755", 
- "modified_by": "Administrator", 
- "module": "Accounts", 
- "name": "SalesInvoice", 
- "owner": "Administrator", 
- "standard": "Yes"
-}
\ No newline at end of file
diff --git a/erpnext/accounts/print_format/__init__.py b/erpnext/accounts/print_format/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/erpnext/accounts/print_format/__init__.py
diff --git a/erpnext/accounts/Print Format/Cheque Printing Format/Cheque Printing Format.json b/erpnext/accounts/print_format/cheque_printing_format/cheque_printing_format.json
similarity index 100%
rename from erpnext/accounts/Print Format/Cheque Printing Format/Cheque Printing Format.json
rename to erpnext/accounts/print_format/cheque_printing_format/cheque_printing_format.json
diff --git a/erpnext/accounts/Print Format/Payment Receipt Voucher/Payment Receipt Voucher.json b/erpnext/accounts/print_format/payment_receipt_voucher/payment_receipt_voucher.json
similarity index 100%
rename from erpnext/accounts/Print Format/Payment Receipt Voucher/Payment Receipt Voucher.json
rename to erpnext/accounts/print_format/payment_receipt_voucher/payment_receipt_voucher.json
diff --git a/erpnext/accounts/Print Format/POS Invoice/POS Invoice.json b/erpnext/accounts/print_format/pos_invoice/pos_invoice.json
similarity index 100%
rename from erpnext/accounts/Print Format/POS Invoice/POS Invoice.json
rename to erpnext/accounts/print_format/pos_invoice/pos_invoice.json
diff --git a/erpnext/accounts/print_format/sales_invoice/__init__.py b/erpnext/accounts/print_format/sales_invoice/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/erpnext/accounts/print_format/sales_invoice/__init__.py
diff --git a/erpnext/accounts/Print Format/SalesInvoice/SalesInvoice.html b/erpnext/accounts/print_format/sales_invoice/sales_invoice.html
similarity index 100%
rename from erpnext/accounts/Print Format/SalesInvoice/SalesInvoice.html
rename to erpnext/accounts/print_format/sales_invoice/sales_invoice.html
diff --git a/erpnext/accounts/print_format/sales_invoice/sales_invoice.json b/erpnext/accounts/print_format/sales_invoice/sales_invoice.json
new file mode 100644
index 0000000..37baa1c
--- /dev/null
+++ b/erpnext/accounts/print_format/sales_invoice/sales_invoice.json
@@ -0,0 +1,14 @@
+{
+ "creation": "2013-03-21 15:24:28",
+ "doc_type": "Sales Invoice",
+ "docstatus": 0,
+ "doctype": "Print Format",
+ "idx": 1,
+ "modified": "2014-05-13 17:51:43.245831",
+ "modified_by": "Administrator",
+ "module": "Accounts",
+ "name": "Sales Invoice",
+ "owner": "Administrator",
+ "print_format_type": "Server",
+ "standard": "Yes"
+}
diff --git a/erpnext/accounts/Print Format/Sales Invoice Classic/Sales Invoice Classic.json b/erpnext/accounts/print_format/sales_invoice_classic/sales_invoice_classic.json
similarity index 100%
rename from erpnext/accounts/Print Format/Sales Invoice Classic/Sales Invoice Classic.json
rename to erpnext/accounts/print_format/sales_invoice_classic/sales_invoice_classic.json
diff --git a/erpnext/accounts/Print Format/Sales Invoice Modern/Sales Invoice Modern.json b/erpnext/accounts/print_format/sales_invoice_modern/sales_invoice_modern.json
similarity index 100%
rename from erpnext/accounts/Print Format/Sales Invoice Modern/Sales Invoice Modern.json
rename to erpnext/accounts/print_format/sales_invoice_modern/sales_invoice_modern.json
diff --git a/erpnext/accounts/Print Format/Sales Invoice Spartan/Sales Invoice Spartan.json b/erpnext/accounts/print_format/sales_invoice_spartan/sales_invoice_spartan.json
similarity index 100%
rename from erpnext/accounts/Print Format/Sales Invoice Spartan/Sales Invoice Spartan.json
rename to erpnext/accounts/print_format/sales_invoice_spartan/sales_invoice_spartan.json
diff --git a/erpnext/buying/Print Format/Purchase Order Classic/Purchase Order Classic.json b/erpnext/buying/print_format/purchase_order_classic/purchase_order_classic.json
similarity index 100%
rename from erpnext/buying/Print Format/Purchase Order Classic/Purchase Order Classic.json
rename to erpnext/buying/print_format/purchase_order_classic/purchase_order_classic.json
diff --git a/erpnext/buying/Print Format/Purchase Order Modern/Purchase Order Modern.json b/erpnext/buying/print_format/purchase_order_modern/purchase_order_modern.json
similarity index 100%
rename from erpnext/buying/Print Format/Purchase Order Modern/Purchase Order Modern.json
rename to erpnext/buying/print_format/purchase_order_modern/purchase_order_modern.json
diff --git a/erpnext/buying/Print Format/Purchase Order Spartan/Purchase Order Spartan.json b/erpnext/buying/print_format/purchase_order_spartan/purchase_order_spartan.json
similarity index 100%
rename from erpnext/buying/Print Format/Purchase Order Spartan/Purchase Order Spartan.json
rename to erpnext/buying/print_format/purchase_order_spartan/purchase_order_spartan.json
diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index f575938..d8f210b 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -40,3 +40,4 @@
 erpnext.patches.v4_0.remove_india_specific_fields
 execute:frappe.delete_doc_if_exists("DocType", "Warehouse User")
 execute:frappe.db.sql("delete from `tabWebsite Item Group` where ifnull(item_group, '')=''")
+execute:frappe.delete_doc("Print Format", "SalesInvoice")
diff --git a/erpnext/selling/Print Format/Quotation Classic/Quotation Classic.json b/erpnext/selling/print_format/quotation_classic/quotation_classic.json
similarity index 100%
rename from erpnext/selling/Print Format/Quotation Classic/Quotation Classic.json
rename to erpnext/selling/print_format/quotation_classic/quotation_classic.json
diff --git a/erpnext/selling/Print Format/Quotation Modern/Quotation Modern.json b/erpnext/selling/print_format/quotation_modern/quotation_modern.json
similarity index 100%
rename from erpnext/selling/Print Format/Quotation Modern/Quotation Modern.json
rename to erpnext/selling/print_format/quotation_modern/quotation_modern.json
diff --git a/erpnext/selling/Print Format/Quotation Spartan/Quotation Spartan.json b/erpnext/selling/print_format/quotation_spartan/quotation_spartan.json
similarity index 100%
rename from erpnext/selling/Print Format/Quotation Spartan/Quotation Spartan.json
rename to erpnext/selling/print_format/quotation_spartan/quotation_spartan.json
diff --git a/erpnext/selling/Print Format/Sales Order Classic/Sales Order Classic.json b/erpnext/selling/print_format/sales_order_classic/sales_order_classic.json
similarity index 100%
rename from erpnext/selling/Print Format/Sales Order Classic/Sales Order Classic.json
rename to erpnext/selling/print_format/sales_order_classic/sales_order_classic.json
diff --git a/erpnext/selling/Print Format/Sales Order Modern/Sales Order Modern.json b/erpnext/selling/print_format/sales_order_modern/sales_order_modern.json
similarity index 100%
rename from erpnext/selling/Print Format/Sales Order Modern/Sales Order Modern.json
rename to erpnext/selling/print_format/sales_order_modern/sales_order_modern.json
diff --git a/erpnext/selling/Print Format/Sales Order Spartan/Sales Order Spartan.json b/erpnext/selling/print_format/sales_order_spartan/sales_order_spartan.json
similarity index 100%
rename from erpnext/selling/Print Format/Sales Order Spartan/Sales Order Spartan.json
rename to erpnext/selling/print_format/sales_order_spartan/sales_order_spartan.json
diff --git a/erpnext/stock/Print Format/Delivery Note Classic/Delivery Note Classic.json b/erpnext/stock/print_format/delivery_note_classic/delivery_note_classic.json
similarity index 100%
rename from erpnext/stock/Print Format/Delivery Note Classic/Delivery Note Classic.json
rename to erpnext/stock/print_format/delivery_note_classic/delivery_note_classic.json
diff --git a/erpnext/stock/Print Format/Delivery Note Modern/Delivery Note Modern.json b/erpnext/stock/print_format/delivery_note_modern/delivery_note_modern.json
similarity index 100%
rename from erpnext/stock/Print Format/Delivery Note Modern/Delivery Note Modern.json
rename to erpnext/stock/print_format/delivery_note_modern/delivery_note_modern.json
diff --git a/erpnext/stock/Print Format/Delivery Note Packing List Wise/Delivery Note Packing List Wise.json b/erpnext/stock/print_format/delivery_note_packing_list_wise/delivery_note_packing_list_wise.json
similarity index 100%
rename from erpnext/stock/Print Format/Delivery Note Packing List Wise/Delivery Note Packing List Wise.json
rename to erpnext/stock/print_format/delivery_note_packing_list_wise/delivery_note_packing_list_wise.json
diff --git a/erpnext/stock/Print Format/Delivery Note Spartan/Delivery Note Spartan.json b/erpnext/stock/print_format/delivery_note_spartan/delivery_note_spartan.json
similarity index 100%
rename from erpnext/stock/Print Format/Delivery Note Spartan/Delivery Note Spartan.json
rename to erpnext/stock/print_format/delivery_note_spartan/delivery_note_spartan.json