The eDrex tool - Leaving Dinosaurs Behind

H. Pihlajamaa, EPO Director Patent Law

During the last few years the EPO has been investing in the overhaul of its IT systems with the major purpose to streamline the procedure by processing European patent applications electronically. A further aim of this exercise is to increase the accuracy of the publications of both patent applications and patent specifications. In order to achieve this, the Office, in a first step, discontinued its past practice governing the form of amendments and thus no longer accepts handwritten amendments in documents replacing parts of the European patent application (Rule 50(1) EPC in conjunction with Rule 49(8) EPC; see also the Notice from the EPO dated 8 November 2013, OJ 2013, 603). In a next step the Office has developed a tool for examiners to produce the Druckexemplar electronically (“eDrex”). This tool allows in particular for the electronic insertion of amendments by the Examining Division to the text of the patent intended for grant.

Yet concerns have been raised about the accuracy of the OCR source that eDrex uses and the ensuing risks for applicants.

The purpose of this article is to provide relevant technical information on the eDrex tool and its functionalities and to clarify certain legal aspects arising from the introduction of this new tool.

The eDrex tool

Documents may be filed with the EPO on paper, by fax, or electronically (pdf or xml); after filing they are included in the electronic file as an image. The new eDrex tool provides examiners with the possibility to edit the Druckexemplar electronically.

The examiner can make amendments to the Druckexemplar in two different ways. The first, image mode, works on the scanned image submitted by the applicant. Text can be deleted or added and all unamended text on the page remains as filed by the applicant. The second, text mode, is where the examiner can make changes to an OCRed version of the original page. Here, amendment is similar to editing with a traditional word processor where text can be added or deleted just like in MS Word. In addition to these two main ways of preparing the electronic Druckexemplar, there is also a bitmap mode which is used infrequently for amendments to drawings. Pages edited using image or bitmap mode are indicated as “AMENDED” in the header of the Druckexemplar. Pages edited using text mode/OCR data are specifically indicated by “AMENDED/OCR”.

Any amendments or corrections using the electronic tool are indicated by means of standard marks and any insertion is made in-line. Detailed explanations on the standard marks used are contained in the Guidelines for examination before the EPO, Annex to C-V. A further advantage of this tool is that all amended pages are tracked and this information is automatically transferred to the communication under Rule 71(3) EPC (forms 2004C or 2004W). This functionality immensely improves the quality and accuracy of this communication.

Relevant legal aspects

The text (Druckexemplar) issued with the communication under Rule 71(3) EPC can only be the subject of a decision to grant if approved by the applicant (Art. 113(2) EPC). Given the opportunities an applicant has at any stage up to and including the final approval to check the accuracy of the text of the patent, corrections in the patent documents after grant are no longer accepted and the responsibility for any remaining errors lies with the applicant (see decision G 1/10, OJ EPO 2013, 194).

During the electronic preparation of the Druckexemplar, alterations in the text of the patent may occur. These so-called formatting/editing errors may be characterized by e.g. the shifting of text lines outside the margins of a document with the consequence that they are deleted or any OCR errors on the pages that were edited in text mode. These alterations are typically neither indicated by standard marks in the Druckexemplar nor in Form 2004.

Although already contained in the text approved by the applicant, these errors may be corrected under Rule 140 EPC upon a careful assessment of all relevant circumstances of each case by the competent division (see Guidelines for examination before the EPO, H-VI, 4). This kind of correction can be carried out by the EPO of its own motion or at the request of the patent proprietor.

However, for the text in or around the amended part(s) of the text of the patent requests for correction of errors will in principle not benefit from this exceptional handling, even if they were introduced by the Examining Division or otherwise arose during the automated process of the Druckexemplar. It is expected that the applicant ensures that the amended part of the text is correct when receiving the communication under Rule 71(3) EPC. Substantive amendments deliberately introduced by the Examining Division are also not covered by the new Guideline since they do not qualify as formatting or editing errors.


The EPO strives to ensure the high quality of its work, including any OCR processing of application documents. The text version available to the Examiner when preparing the Druckexemplar in text mode comes from a high quality OCR conversion with a quality of 99.995% accuracy (the same standard as used for all A and B publications for the last 20 years). This is achieved at considerable expense by a combination of automated conversions and human intervention to verify areas where doubts occur. This is especially the case with certain letter combinations (e.g. “rn” vs “m”), with symbols (such as “μ”, “β” or “Å”) or with more complex text such as tables and mathematical or chemical formulae. In addition, examiners receive intensive training with the new tool.

When documents submitted to the EPO comply with the requirements of the EPC as regards text size and spacing, line spacing, quality of the print, margins etc., as well as by avoiding fax and paper submissions where possible (see in particular Rule 49 EPC), OCR errors will be reduced significantly, if not avoided.

The EPO trusts that this new key development will prove to be of long term benefit for all stakeholders in supporting the quality and efficiency of the patent grant procedure.