GPI coverage and content

You can use Global Patent Index (GPI) to carry out detailed searches in the EPO's worldwide bibliographic (DOCDB), legal event (INPADOC) and full-text data sets, and download or visualise the search results for statistical analysis.

Current content: 156 511 693 patent documents

This week's update (14/06/2024 12:00 CET):

200 241 new documents added

1 026 356 documents amended

GPI key values

Run regular monitoring (e.g. monthly or quarterly) of technical areas or companies

Use built-in charts to visualise technical trends and patenting activity of companies

Choose the data you want to see and download to focus on what you are interested in

Run data quality assessments to measure the risk of incomplete search results

EP 0004573 B1 19811014 - XEROGRAPHIC COPIER

Title (en)

XEROGRAPHIC COPIER

Publication

EP 0004573 B1 19811014 (EN)

Application

EP 79100715 A 19790309

Priority

US 89495578 A 19780410
US 89495678 A 19780410
US 89495778 A 19780410

Abstract (en)

[origin: EP0004573A1] In a test cycle, either at the end of a short copy production run or during an interruption in a longer copy production run, a xerographic copier is arranged to produce a toned test patch (30) in an otherwise cleaned imaging area (28) of the photoconductor (26). The optical density of both the cleaned and test areas are sensed by an electro-optic system to provide output signals indicating the respective densities. These signals are compared in a control circuit primarily to provide output signals indicating requirement for replenishment of the developer mix with toner.

IPC 1-7

G03G 15/00

IPC 8 full level

G03G 15/00 (2006.01)

CPC (source: EP)

G03G 15/5041 (2013.01); G03G 2215/00042 (2013.01)

Designated contracting state (EPC)

BE CH DE FR GB IT NL SE

DOCDB simple family (publication)

EP 0004573 A1 19791017; EP 0004573 B1 19811014; DE 2960963 D1 19811224

DOCDB simple family (application)

EP 79100715 A 19790309; DE 2960963 T 19790309