DE102007060022B4 - Method for controlling the heat emission to a printing substrate in a fuser station of an electrographic printer or copier - Google Patents

Abstract

Method for controlling the heat output to a substrate in a fuser of an electrographic printing or copying device, are assigned to the individually operable heating modules (10) heating zones (2) on the substrate (1), each heat to the associated heating zones (2) emit the printing material (1), in which are provided as heating modules (10) infrared heaters, which are separately controllable, in which above the printing material (1) a transversely to the direction of movement of the printing material (1) movable Strahlungsumlenkeinheit (4) is arranged, the from the printing material (1) emanating heat rays (3) to a temperature sensor (5) which emits a dependent of the strength of the heat rays (3) measuring signal (SS), in which with a at the output of the temperature sensor (5) arranged controller (9 ) - from the measurement signal (SS) of the temperature sensor (5) per heating zone (2), a temperature actual value is determined, - this actual temperature value with one of the respective Hei zzone (2) predetermined temperature setpoint is compared and - in the case of deviation of the actual temperature value from the temperature setpoint, a deviation-dependent control signal (SI) for each heating module (10) is generated, the heat output of the heating module (10 ) controls.

Description

Electrographic printing or copying machines are known, see, for. B. WO 98/39691 A1 , In such a printing or copying machine are on a charge image carrier, for. B. a photoconductor belt, generated by a character generator charge images of the images to be printed. Subsequently, the charge image carrier is moved past developer stations, one per color. These transport z. B. toner and carrier existing developer to the charge image carrier. According to the charge images on the charge image carrier, the toner transfers to the charge image carrier and colors it. In the next step, the toner images are transferred to a substrate and fixed on it. The exact sequence of the printing process can be found in WO 98/39691 A1.

The fixation of the toner images on the substrate can be done on the principle of thermosetting. The toner images are melted into the substrate. For fixing z. B. fuser rollers, of which at least one is heated, are used. In another solution of thermosetting infrared heaters are used as heating sources. In this case, infrared radiators are arranged in the fuser above the side of the printing material on which the toner images are to be fixed, which emit infrared rays in the direction of the printing material. The infrared radiators can then be divided into groups, which are each assigned to a heating zone on the substrate.

In order to avoid excessive heating of the printing material, which in the worst case can lead to fire or damage to the printing substrate, it is known to measure the temperature of the printing material after fixing and to control the heating sources as a function of the measuring signal in such a way that damage to the substrate is omitted, but the toner images are sufficiently fixed in the substrate. As measuring means temperature sensors z. B. Infrared sensors are arranged above the substrate, which measure the emanating from the substrate heat rays. The measuring signal emitted by the temperature sensors is then used to control the heating sources.

A method of measuring the temperature of a continuous web of thin material is over DE 16 98 084 A ( US Pat. No. 3,535,630 A ) known. For this purpose, an infrared radiation sensor is arranged on one side of the web, which determines the temperature of the web as a function of the emanating from the web infrared radiation.

Other arrangements with which the temperature of a printing material can be measured, are out JP 2002-116655 AA (Abstract) and JP 2006-243 468 A (Abstract) known. The determination of the temperature of the printing material takes place in each case via the measurement of the infrared radiation emitted by the printing substrate.

DE 102 25 603 A1 and DE 101 45 002 A1 describe a device for fixing toner on a substrate in an electrographic printing module. For fixing a fixing roller is used. In order to increase the fixing speed, an additional heating of resonators is arranged before or after the fixing roller. The resonators are arranged offset to one another and are operated such that the maxima of the emitted microwaves are adjacent to each other, so that the most uniform possible temperature curve across the width of the substrate. The aim is thus to achieve a uniform heating across the width of the substrate.

In EP 0 263 896 A1 a measuring arrangement is described with which the temperature of the axle bearings can be measured when moving railway cars. For this purpose, emanating from the axis heat rays, here infrared rays, measured. The axle runs in a warehouse, which is held below the railroad car by a carrier. The emanating from the axis heat rays are passed through a vibrating mirror or a polygon mirror and a lens to an IR sensor and measured by this. Since the carriers are designed differently for different railway cars, but always the same measuring arrangement is to be used for measuring the temperature, the heat rays are scanned across the width of the bearing by the mirror. This ensures that even heat rays pass directly from the axis to the sensor.

DE 10 2004 040 777 A1 discloses an arrangement for determining the heat requirement, which have to apply the fixing means for fixing the toner images on a substrate. For this purpose, a reference radiation source irradiates the substrate. A temperature sensor measures the heat emitted by the substrate. An evaluation circuit determines the heat output requirement of the substrate from the measurement result.

To determine the temperature of the printing material over its entire width, across the width of the substrate several temperature sensors, eg. B. three temperature sensors are arranged. Each temperature sensor then measures a range of the printing material, hereinafter referred to as heating zone, and from the measured signals emitted by the temperature sensors, the temperature of the Bedruckstoffs can be determined. If the entire heating source is constructed such that a per heating zone provided separately controllable heating module, the respective heating zones can be supplied individually thermal energy.

In measurement arrangements with several temperature sensors along the width of the printing material, a problem then arises when substrates of different widths are to be processed. In the case of a printing material whose width is smaller than the maximum width of a printing material permitted for the printing, a measuring signal which does not depend exclusively on the temperature on the printing material is emitted in the edge region by the temperature sensors assigned to this region. If, in this case, the measuring signals are used to control the heating modules, this can damage the printing material.

The problem to be solved by the invention is to specify a method with which the temperature of a printing material of different width can be determined in order to be able to use the temperature signal to selectively control a heating source which heats the printing material over its entire width.

This problem is solved according to the features of claim 1.

An arrangement for detecting the temperature (referred to below as the measuring arrangement) of a moving printing material has a radiation deflecting unit which is movable transversely to the direction of movement of the printing material and directs the heat rays emanating from the printing material to a temperature sensor which emits a measuring signal dependent on the intensity of the heat rays , The advantage of this measuring arrangement is, inter alia, that only one temperature sensor is required and still the temperature can be determined over the entire width of the printing material. Furthermore, the measuring arrangement z. B. are arranged according to a fuser such that only a small footprint at the output of the fuser is necessary for them. For example, only the radiation deflecting unit needs to be placed adjacent to the substrate.

If the measuring arrangement is used in an electrographic printing or copying machine when operating a fuser for controlling the heat output of a heating module, a controller can be arranged at the output of the temperature sensor, which determines a temperature actual value from the measurement signal of the temperature sensor and this with a the heating module the heat source predetermined temperature setpoint compares and generates depending on the deviation of the two temperature values from each other a control signal for the heating module that controls the heat output of the heating module so that the predetermined temperature is maintained on the substrate.

If at least two individually operable heating modules per fixing station are provided, the heating zones are assigned to the printing material, the controller can determine from the actual temperature value of the respective heating zone and the temperature setpoint associated with the respective heating zone the control signal assigned to the respective heating module.

Further developments of the invention will become apparent from the dependent claims.

As a radiation deflecting unit, a rotating mirror, in particular a polygon mirror, can be used. This can be driven by a motor to detect the heat rays across the width of the substrate and forward it to a temperature sensor. The temperature sensor can, for. B. be a pyrometer.

The temperature sensor can be designed as an infrared sensor and measure the emanating from the substrate infrared rays. Then it is advantageous if an optical filter is arranged in front of the infrared sensor, which filters out the infrared rays from the heat rays.

In order to increase the accuracy of the measuring method, the controller can determine from the measuring signal per heating zone offset in time at least two actual temperature values, and from these the heating zone associated control signal. For example, the control signal associated with a heating zone can be determined from the mean value of the actual temperature values associated with the heating zone. As heating modules infrared radiators can be used, which are separately controllable. These can be realized as foil radiation modules.

With reference to an embodiment, which is illustrated in the figures, the invention will be further explained. Show it:

1 a schematic diagram of the measuring method according to the invention;

2 a perspective view of the measuring arrangement when using a polygon mirror as Strahlungsumlenkeinheit;

3 a block diagram of a control circuit that uses the measurement signal for controlling heating modules;

4 the temperature profile along a substrate.

The invention will be explained in connection with an electrographic printing or copying machine, in which on a substrate, for. As a paper web, toner images to be fixed by heat. This fixation can be done in a known manner using infrared radiators, which are arranged on the toner images having the side of the printing substrate in the fuser. To z. B. to avoid damage to the substrate, the temperature should be monitored in the fuser to control the infrared heaters so that these problems do not occur. However, the invention is not limited to this application.

Out 1 gives a schematic representation of the measuring method according to the invention. On a substrate 1 , z. B. a paper web is intended in three zones, in the following heating zones 2 called, the temperature to be monitored. The heating zones 2 are by a heat source, eg. B. by infrared radiators (not shown), heated. The of the substrate 1 emitted heat rays 3 be from a radiation deflecting unit 4 towards a temperature sensor 5 ( 2 ) redirected. The deflected measuring beam is in 1 with the reference numeral " 6 " designated. The radiation deflecting unit 4 It is moved so that it exceeds the width of the substrate 1 the heat rays emitted 3 to the temperature sensor 5 deflects. This results in a measurement line 7 , because of the forward movement of the printing material 1 diagonally across the substrate 1 runs. In 1 are three heating zones 2 intended. Of course, the number of heating zones 2 be chosen larger or smaller.

Out 2 the result is a perspective view of the measuring arrangement MA according to the invention. As a radiation deflecting unit 4 a rotating mirror can be provided; z. B. can be a polygon mirror 8th be used. From the substrate 1 be in a scanning area 6 the heat rays 3 from the polygon mirror 8th as measuring beam 6 to a temperature sensor 5 diverted. In front of the temperature sensor 5 For example, a filter can be arranged to only heat rays of a predetermined frequency range to the temperature sensor 5 to steer, z. B. can only the infrared rays to the temperature sensor 5 be steered. As a temperature sensor 5 a commercial temperature sensor can be used. If infrared rays are used in the measurement, a commercially available infrared sensor can be used as the temperature sensor.

In 2 is the beam path of the substrate 1 to the polygon mirror 8th and from there to the temperature sensor 5 shown. The polygon level 8th sequentially detects the heat rays 3 across the width of the substrate 1 and directs the heating zones 2 associated heat rays 3 to the temperature sensor 5 , Thus, it is possible that of the individual heating zones 2 emitted heat rays 3 evaluate consecutively to the individual heating zones 2 to control separately assigned heating modules.

3 shows a block diagram of a control circuit RS, with the heating zones 2 can be adjusted individually to a predetermined temperature setpoint. By the measuring arrangement, which the Strahlungsumlenkeinheit 4 and the temperature sensor 5 has, the temperature per heating zone 2 measured after each other and the control circuit RS supplied as a measurement signal SS. The control circuit RS can be used as a controller 9 have a conventional μController. The regulator 9 , which determines the temperature setpoints of each heating zone 2 z. B. contains in a memory, determined from the measurement signals SS, the actual temperature values, comparing per heating zone 2 the actual temperature values with the temperature setpoints and generates depending on a deviation in each case a control signal for the respective heating modules 10 for heating the printing material 1 , The evaluation of the measurement signals SS by the controller 9 takes place in a known manner.

With the invention, the control of the individual heating zones 2 made optimal according to the invention. One advantage is that the evaluation of the measurement signals SS to the width of the substrate 1 can be adjusted. As the width of the substrate 1 is known, the control circuit RS can be adjusted accordingly. The course of the temperature t can 4 be removed. Shown is the course of the temperature t plotted against the maximum width bm of the scanning of the printing substrate 1 through the radiation deflecting unit 4 , In the area I with the width b1, in the substrate 1 in the heating zones 2 is present, the radiated heat is high, in area II, in which no substrate 1 rests, the radiated heat falls to a smaller value.

The invention can be used in particular in a fuser of an electrographic printing device. The advantage is that the individual heating zones 2 can be adjusted in the fuser specifically with respect to the temperature. This will be an optimal fixation of the toner images on the substrate 1 regardless of the width of the substrate 1 possible. The fuser can have at least two, in particular three, heating zones 2 have, which can be controlled separately, so that on the substrate 1 an optimal fixation of the toner images takes place. Per heating zone 2 can z. B. several Auswertezeitpunke be selected to which the temperatures of the printing material 1 be determined.

LIST OF REFERENCE NUMBERS

MA

measuring arrangement

RS

control circuit

SI

control signal

SS

measuring signal

t

temperature

b

Width of the substrate

1

substrate

2

heating zone

3

heat rays

4

Strahlungsumlenkeinheit

5

temperature sensor

6

measuring beam

7

measuring line

8th

rotating mirror

9

regulator

10

heating module

Claims (9)

Method for controlling the heat emission to a printing substrate in a fuser station of an electrographic printing or copying device, in which individually operable heating modules ( 10 ) Heating zones ( 2 ) on the substrate ( 1 ), each of which transfers heat to the associated heating zones ( 2 ) on the substrate ( 1 ), in which as heating modules ( 10 ) Infrared radiators are provided, which are separately controllable, in which above the substrate ( 1 ) a transversely to the direction of movement of the printing substrate ( 1 ) movable radiation deflecting unit ( 4 ), which depends on the substrate ( 1 ) outgoing heat rays ( 3 ) to a temperature sensor ( 5 ) that deflects the heat rays ( 3 ) dependent measurement signal (SS), in which one with at the output of the temperature sensor ( 5 ) regulators ( 9 ) - from the measuring signal (SS) of the temperature sensor ( 5 ) per heating zone ( 2 ) a temperature actual value is determined, - this actual temperature value with one of the respective heating zone ( 2 ) is compared to the predetermined temperature setpoint and - in the case of deviation of the actual temperature value from the temperature setpoint, a deviation-dependent control signal (SI) for the respective heating module ( 10 ) is generated, the heat output of the heating module ( 10 ) controls. Method according to Claim 1, in which the radiation deflecting unit ( 4 ) a rotating mirror ( 8th ). Method according to Claim 1, in which the radiation deflecting unit ( 4 ) a polygon mirror ( 9 ). Method according to one of claims 1 to 3, wherein the temperature sensor ( 5 ) is an infrared sensor, the of the substrate ( 1 ) measures outgoing infrared rays. Method according to Claim 4, in which there is arranged in front of the infrared sensor an optical filter which is produced from the heat rays ( 3 ) filters out the infrared rays. Method according to one of claims 1 to 3, wherein the temperature sensor ( 5 ) is a pyrometer. Method according to one of the preceding claims, in which the controller ( 9 ) the measuring signal (SS) per heating zone ( 2 ) evaluated offset in time at least twice and used to determine the actual temperature value. Method according to Claim 7, in which the controller ( 9 ) that the heating module ( 10 ) associated control signal (SI) from the average of the heating zone ( 2 ) associated temperature actual values determined. Method according to one of the preceding claims, in which foil radiation modules are used as the infrared radiator.

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