Sensorless function monitoring of drying via plausibility monitoring of power consumption

Patent metadata

Field	Value
Publication number	US-9375952-B2
Application number	US-201514823373-A
Country	US
Kind code	B2
Filing date	Aug 11, 2015
Priority date	Aug 12, 2014
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

In a method or device to determine a lift state of a recording medium from a surface of a heating saddle of an inkjet printing system, the recording medium being directed past the surface for drying, an index for power consumption of the heating saddle is determined including a determination of a time curve of the electrical power consumed by the heating saddle. The power consumption of the heating saddle depends on a desired temperature of the heating saddle. The lift state of the recording medium is determined based on the index for the power consumption.

First claim

We claim as our invention:

1. A method to determine a lift state of a recording medium from a surface of a heating saddle of an inkjet printing system, the recording medium being directed past the surface of the heating saddle for drying, comprising the steps of:
determining an index for power consumption of the heating saddle, the determining of the index for the power consumption including a determination of a time curve of the electrical power consumed by the heating saddle, the power consumption of the heating saddle depending on a desired temperature of the heating saddle; and
determining a lift state of the recording medium based on the index for the power consumption without using a sensor to measure a temperature of the recording medium.

2. The method according to claim 1 wherein the lift state includes at least one of the following states:
the recording medium rests on a surface of the heating saddle;
the recording medium is not in direct contact with the surface of the heating saddle; and
after being directed past the heating saddle, the recording medium has a degree of moisture that is greater than or equal to a predefined moisture threshold.

3. The method according to claim 1 wherein the index for the power consumption includes an index for electrical power consumed by the heating saddle in a predefined time period.

4. The method according to claim 1 wherein the index for the power consumption:
depends on the desired temperature;
increases if the desired temperature increases; and
decreases if the desired temperature decreases.

5. The method according to claim 1 wherein a temperature of the heating saddle is regulated relative to the desired temperature.

6. The method according to claim 1 wherein:
an electrical heating of the heating saddle is activated if a temperature of the heating saddle reaches or falls below a lower temperature threshold;
the lower temperature threshold is less than the desired temperature;
the electrical heating of the heating saddle is deactivated if the temperature of the heating saddle reaches or exceeds an upper temperature threshold; and
the upper temperature threshold is greater than the desired temperature.

7. The method according to claim 6 wherein the index for the power consumption includes at least one of:
a frequency of the activation of the electrical heating of the heating saddle;
a time interval between two successive activations of the electrical heating of the heating saddle;
a duration of the electrical heating of the heating saddle; and
an electrical energy consumed by the heating saddle per time unit upon heating.

8. The method according to claim 1 additionally including
comparing the index for the power consumption with a predefined power threshold; and
determining the lift state of the recording medium depending on whether the index for the power consumption is greater than or less than the predefined power threshold.

9. A method to determine a lift state of a recording medium from a surface of a heating saddle of an inkjet printing system, the recording medium being directed past the surface of the heating saddle for drying, comprising the steps of:
determining an index for power consumption of the heating saddle, the determining of the index for the power consumption including a determination of a time curve of the electrical power consumed by the heating saddle, the power consumption of the heating saddle depending on a desired temperature of the heating saddle;
determining a lift state of the recording medium based on the index for the power consumption including determining that a negative pressure is applied to the heating saddle in order to draw the recording medium onto a surface of the heating saddle, and on the basis of the index for the power consumption, determining that the recording medium is not in direct contact with the surface of the heating saddle; and
thereupon inducing a printing process of the inkjet printing system to be interrupted.

10. A controller for a dryer of an inkjet printing system, the dryer including a heating saddle with a surface heated to a desired temperature, the controller performing the steps of:
determining an index for power consumption of the heating saddle while a recording medium is directed past the surface of the heating saddle for drying, the determining of the index for the power consumption including a determination of a time curve of electrical power consumed by the heating saddle, the power consumption of the heating saddle depending on the desired temperature of the heating saddle; and
determining a lift state of the recording medium from a surface of the heating saddle based on the index for the power consumption without using a sensor to measure a temperature of the recording medium.

11. An inkjet printing system, comprising:
a plurality of inkjet print heads followed by a dryer comprising a heating saddle with a surface heated to a desired temperature; and
a controller for the dryer which determines an index for power consumption of the heating saddle while a recording medium is directed past the surface of the heating saddle for drying, the index for the power consumption including a determination of a time curve of electrical power consumed by the heating saddle, the power consumption of the heating saddle depending on the desired temperature of the saddle, and the controller determining a lift state of the recording medium from a surface of the heating saddle based on the index for the power consumption without using a sensor to measure a temperature of the recording medium.

Assignees

• Oce Printing Systems Gmbh & Co Kg
• Oce Printing Systems Gmbh & Co Kg

Inventors

• Biglari Mehrad
• Heimbach Robert
• Lang Robert

Classifications

• B41J11/0085

  Using suction for maintaining printing material flat (on rotatable drums B41J13/226) · CPC title

• B41J11/002 Primary

  Curing or drying the ink on the copy materials, e.g. by heating or irradiating · CPC title

• B41J11/00242 Primary

  Controlling the temperature of the conduction means · CPC title