DE102016221077A1 - Ambient light measurement at arc height - Google Patents

Abstract

The invention relates to a device for enabling visual assessment of print quality by operators with a sheet storage device (11) for receiving substrates (9) and a controllable light source (5, 5a, 5b) illuminating the sheet storage device (11). The invention is characterized in that a sensor device (6) is provided, which measures the light of the light source (5, 5a, 5b) at the level of the printing material (9) and is connected to a control computer (7), and in dependence the measured values of the sensor device (6) the light source (5, 5a, 5b) is controlled by the control computer (7).

Description

The present invention relates to a device for enabling the visual assessment of print quality by operators with a sheet deposition device for receiving substrates and a controllable light source illuminating the sheet deposition device.

A generic device is known from the prior art of the patent DE 10 2005 001 417 B4 known. This patent discloses a sheet tray of a printing press with a projection device on the front of the sheet filing desk and a camera arranged above the filing desk. The sheet storage desk thus represents the control station of a printing press. It is envisaged that a projector and a Farbprüfleuchte are combined in a projection lamp. In this way it is possible to project both an image on a printing sheet, which rests on the sheet support surface, as well as to judge the coloration of a printed sheet by means of standard light. In this case, the projector also performs the function of a color test light. In such a Farbprüfleuchte it is possible to control the illumination surface of the Farbprüfleuchte format dependent. In this way, the illumination surface can be adapted to the different sheet formats depending on the current print job. In addition, the color of the light can be chosen arbitrarily. Furthermore, the amount of light projected onto the sheet can be controlled. In this case, it is also possible for at least part of the image to be illuminated with white standard light, while display and operating elements are projected around the sheet.

From the publication DE 10 2010 044 736 A1 is a Farbprüfleuchte known, which works with LED bulbs. The aim is to compensate for the change in the color spectrum of the LED light source due to aging. At regular intervals, a recalibration of the LED bulbs takes place in order to eliminate the changes in the light spectrum due to aging processes. When recalibrating the LED bulbs, all the measurements made during the basic calibration are repeated and the new settings are stored in a microprocessor, which re-marshals the LED bulbs in terms of their light spectrum.

It is an object of the present invention to provide a device for enabling the visual assessment of the print quality by operators with a sheet storage device for receiving substrates and a sheet storage device illuminating, controllable light source, which is able to compensate for extraneous light or ambient light.

This object is achieved by claim 1, advantageous embodiments of the present invention will become apparent from the dependent claims and the drawings and the description.

In the apparatus according to the invention, a sensor device is provided, which may consist of a plurality of sensors which measure the light of the light source for illuminating the printing material in the optical assessment of the print quality at the level of the printing material. This means that the light that falls on the substrate is also measured precisely at this location. In this way, it is ensured that the light that leaves the light source is not measured, but that the light is measured, which actually hits the printing material together with the ambient light. In this way, the influences of the ambient light or the extraneous light are detected in a printing and taken into account in the measurement process. In this case, the sensor device is connected to a control computer, which in turn is in operative connection with the light source. In this way, it is possible for the control computer, on the basis of the measured values at the level of the printing material, to record the deviations from the standard light and to control the light source accordingly as a function of the measured values of the sensor device. In this way, the control computer can compensate deviations in the amount of the printing material to the standard light within the scope of the possibilities of the light source. This ensures that, in changing light conditions around the sheet storage device, the evaluation of the lying on the sheet storage device substrates always with standard light. This is important because the optical assessment of the print quality is dependent on the illumination of the substrate on the sheet storage device and in changing light, the operator can not objectively assess the print quality. The light source may consist of several partial light sources, such as e.g. consist of several LEDs or fluorescent tubes, which can be controlled differently. Thus, parts of the printing material can be specifically illuminated differently, if e.g. External light from a window hits only parts of the substrate. Thus, an effective compensation for partial external light is possible.

In a first embodiment of the present invention, it is provided that the light source consists of several LED lights. These LED lights have LEDs in the colors red, green and blue, which together trigger a white light. By appropriate control of the LED lights by the Control computer different white tones can be displayed and set the desired standard light. Furthermore, unlike other bulbs, LED lights are very energy efficient and durable.

Advantageously, it is additionally provided that the sensor device is part of a color measuring device movably arranged on the sheet depositing device. In order to measure the light of the light source at the level of the printing substrate, the sensors must be arranged correspondingly close to the sheet deposition device, so that they can detect exactly the light which impinges at the level of the printing material. One possibility for this is to use a color measuring device which is present in any case for color measuring operations and which is movably arranged on the sheet depositing device. In this case, the sensors for detecting the light of the light source are mounted on top of the side facing away from the sheet depositing device of the color measuring device. By moving the color measuring device, the sensors can be moved over the entire sheet storage device and thus over the entire substrate and thus made at many locations of the substrate corresponding measurements in the amount of the substrate. The detection of the measured light values by means of the sensors on the upper side of the color measuring device can be done simultaneously with the measurement of the color values on the printing material in one pass. In this way, an already existing color measuring device can be equipped with relatively few sensors in order to measure the light of the light source height of the printing material. There is no need to provide additional movement means which move the sensors over the sheet deposition device at the level of the printing material. If the extraneous light can not be compensated or can not be sufficiently compensated, a warning can be signaled to the operator. This warning can be done via a screen or a flashing signal from the light source of the color test light. Thus, a misjudgment of the substrate is avoided in insufficient lighting.

In a further embodiment of the present invention, it is additionally provided that the light source has additional warm white and / or cool white LEDs and / or UV LEDs in addition to LEDs in the colors red, green and blue. With the warm white and / or cold white LEDs, the light spectrum of the light source can be improved and brought closer to the optimal standard light. As a result, an optimum standard light for assessing the print quality by the operating staff can be achieved at the level of the printing material. The UV LEDs produce the after ISO standard 3664 (2009) prescribed UV light content. By variable control of the UV LEDs, the change in the color impression can be made visible by brighteners in the substrate.

In a further embodiment of the present invention, it is provided that the sensor device is mounted in or on the sheet storage device. In this embodiment of the present invention, the sensors of the sensor device are distributed over the surface of the sheet deposition device and mounted on this itself. So that the substrate still rests flat on the sheet storage device, the sensors are preferably recessed in recesses or recesses of the surface of the sheet storage device mounted so that the surfaces of the sensors flush with the surface of the sheet storage device and lie on one level. This ensures that the substrate rests flat on the sheet storage device. In this embodiment of the invention significantly more sensors are required compared to the embodiment with the sensors on a movably arranged color measuring device, since they are not movable and must be distributed over the entire surface of the sheet storage device. It is also possible to combine the mounted in or on the sheet storage device sensors with the sensors on the movably arranged colorimeter. Since the printers frequently leave sheets on the sheet storage area, it makes sense at certain intervals to remind the printer that he has to clear the area in order to allow an external light measurement. This can be done by optical or acoustic signals.

In a further embodiment of the present invention, it is provided that the sensor device is a camera which is directed onto the sheet deposition surface. In this case, the paint of the sheet storage area is to be designed so that the surface is suitable for the measurement process. Alternatively, there may be several white tiles used for measurement.

A further advantageous embodiment of the present invention is characterized in that the device has a camera for detecting operating processes of the operating personnel. In this embodiment of the present invention, a camera is mounted in the sheet storage, which detects operations of the operator. This allows the control of the light source depending on detected operations. Thus, the control computer, depending on the detected by the camera operations of the operator on the light source and off and make adjustments to the light source. If the operator removes himself from the print quality assessment device, he can the control computer automatically switch off the light source. Furthermore, the control computer, the light source z. B. then turn on when the camera detects operations in the setting of the coloring of the printing press. The presence of the operator can be detected via the camera itself or via additional IR sensors. Furthermore, the camera can also detect the support of a printed sheet on the sheet tray and then switch on the light source. In the opposite case, the light source is switched off. Furthermore, in certain states of the machine, such. B. operator errors, the LEDs of the light source are controlled such that the color of the light changes and by different colors corresponding settings, in particular errors in the machine, the operating personnel are displayed. However, primarily, the detection and operation operations of the operator serve to turn off the light source whenever there is no operation for judging the print quality by the operator, and thus energy can be saved. Furthermore, by switching off the light source extends the life of the light source used in the light source.

Advantageously, provision is also made for standard light values to be stored in the device in a memory and for measured processes by the sensor device to be mathematically compared with the stored standard values and for deviations determined the light source is controlled in such a way that the deviations are compensated or at least minimized. By means of the standard light values stored in the device, the light of the light source can be checked at regular intervals and, in the case of deviations from the standard light values, a corresponding adaptation of the light spectrum of the light source can be carried out by the control computer. This ensures that it is checked at regular intervals whether the light striking the substrate surface still corresponds to the standard light values. In case of deviations, the condition of the standard light is automatically restored. This can be done without intervention of the operator, so that operator error by incorrect adjustment of the light source can be avoided as in the prior art. In a further embodiment of the present invention, it is provided that the type of paper is input in an operating device or the type of paper is determined by a measuring operation with a colorimeter and depending on the paper type, the light type and brightness of the light source is adjusted by the control computer. Different types of paper are due to different optical paper properties, such. As UV brighteners, judged in different light. These different optical properties of the printing material can be considered according to the invention in that either the operator enters the paper type by means of an operating device such as touch screen in the control computer or the paper z. B. is determined by a measuring operation with a colorimeter and thus also the control computer is available. On the basis of the paper type determined in this way, the control computer can then automatically adapt the type of light and brightness of the light source, so that the light suitable for the paper type used is always used to assess the print quality.

In a further embodiment of the present invention, it is provided that in the control computer necessary for the assessment of print quality conditions are stored together with an associated print job and that when processing the print job, the stored conditions are read and the light source is automatically set by the control computer. This embodiment of the invention makes it possible to ensure that the print quality of a print job is judged under the conditions desired by the customer of the print job. Thus, together with the print job, the customer can supply corresponding data of conditions for judging the print quality, and these are then read out from the control computer together with the print job and automatically used to set the light source. These necessary conditions include matching conditions such as. B. Color temperature, brightness, UV content, etc.

The present invention will be described and explained in more detail with reference to several figures. Show it:

1 a control station of a printing machine with a controllable by a control computer light source and arranged in a sheet storage sensors for measuring the light of the light source at the level of the substrate,

2 a control station of a printing press, in which the sensors for detecting the light of the light source are arranged on top of a color measuring device,

3 a light source with red, green and blue LEDs and additional LEDs with cool white and warm white light and

4 a control station with sheet support, in which a substrate rests on the sheet storage.

In 1 is a helm 1 for a printing press 2 displayed. The steering position 1 is via a connection line 3 with the printing press 2 connected. In the helm 1 is a control computer 7 housed, which all functions of the printing press 2 can control. The control computer 7 is still used to receive operator inputs and is therefore with an operating device 12 connected. The operating device 12 includes a touch screen and a trackpad. Furthermore, the control computer 7 with a light source in the form of LED lights 5 connected, which on a shielding roof 4 of the helm 1 are attached. The at the bottom of the shielding roof 4 attached LED lights 5 are thus able to create a sheet storage area 11 illuminate. On the sheet storage area 11 can in 1 not shown printing material sheet 9 which the operating personnel would like to visually check in terms of print quality. In the sheet storage area 11 are distributed over the entire sheet storage area several light sensors 6 embedded, which with the surface of the sheet storage area 11 finish flush. The light sensors 6 are also with the control computer 7 connected and serve the light of the LED lights 5 capture. Because the light sensors 6 at the height of the sheet storage area 11 are arranged and thus also in height of a printing material sheet 9 , the light sensors can 6 that actually in height of the sheet storage area 11 existing light spectrum of the LED lights 5 to capture. This also ambient light and extraneous light is detected, which on the sheet storage area 11 incident. The thus detected light is from the control computer 7 with in the control computer 7 stored standard light values compared. For deviations between the standard light values and the measured values of the light sensors 6 can the control computer 7 the LED lights 5 automatically turn on and restore the standard light. On the right in 1 it can be seen that the LED lights 5 each consist of red, blue and green LEDs, which together generate controlled white light. The LED lights 5 are on the shielding roof 4 spread over the entire area, leaving the sheet storage area 11 in the lower part of the helm 1 can illuminate large areas and evenly. In the lower right half in 1 is the surface of the sheet storage area 11 shown in the top view, which of the LED lights 5 is illuminated. In addition, the light sensors 6 to detect whichever the light of an LED light 5 to capture. This ensures that the light of all LED lights 5 is captured and that of each of the LED lights 5 generated light is actually standard light.

In 2 is an alternative embodiment to 1 shown in place of the in the sheet storage area 11 recessed light sensors 6 a colorimeter 8th for detecting the light of the LED lights 5 which is above the sheet storage area 11 is movably arranged. This allows the colorimeter 8th the entire surface of the sheet storage area 11 run over. On the sheet storage area 11 facing away from the top of the colorimeter 8th are several light sensors 6 attached, showing the light of the LED lights 5 can capture. If the colorimeter 8th on the sheet storage area 11 the light spectra of all LED luminaires 5 be recorded. This process is on the right side in the lower half in 2 indicated where it can be seen that by means of the light sensors 6 on the colorimeter 8th always one row of LED lights 5 can be measured before the colorimeter 8th to the next row of LED lights 5 is moved laterally. In 2 This will be three columns of LED lights 5 recorded before the measuring process is completed.

3 shows an embodiment of the present invention, in which the colored LED lights 5 additional LED lights for the colors warm white 5a and / or cold white 5b assigned. In this way, additional white tones can be achieved through the warm white LED lights 5a and the cool white LED lights 5b generated by the existing red, green, blue LED lights 5 can not be generated. Thus, the spectrum of LED lights 5 through the warm white or cold white LED lights 5a . 5b extended. In addition, not yet shown UV LEDs are provided which make brighteners visible in the substrate.

4 provides substantially the same embodiment as in 2 is only located on the sheet storage area 11 a printing material sheet 9 , which of the LED lights 5 on the shielding roof 4 is illuminated. The substrate sheet 9 can from the colorimeter 8th be measured. In this case, the printing material sheet 9 from the colorimeter 8th initially measured in the unprinted state to detect paper properties such as optical brighteners. Since, depending on the paper properties, a different illumination for assessing the print quality is required, it can be ensured that the correct illumination depending on the substrate used 9 is ensured. Furthermore, the printing material sheet 9 from the colorimeter 8th can also be measured in the printed state in order to carry out a metrological assessment of the print quality by means of the color measuring device 8th make.

Furthermore, the show 4 as well as the 1 and 2 at the front of the shielding roof 4 a camera 10 What operations by the operator at the helm 1 detected. So z. B. be detected, whether the Operating staff at the helm 1 stands and a printing material sheet 9 wants to examine. If no operator is detected, the control computer 7 , which with the camera 10 connected to the LED lights 5 switch off and save electricity. This switching process can also be triggered by the fact that the camera 10 a printing material sheet 9 on the sheet storage area 11 recognizes. If no substrate sheet 9 rests, can also be the LED lights 5 from the control computer 7 be switched off, as obviously no sheet of printing material 9 can be assessed. By detecting the height of the printing material actually incident light can continue the inclination of the sheet storage area 11 be compensated automatically. Because the rear area of the sheet storage area 11 closer to the LED lights 5 is as the front area, the lighting conditions change in the rear area compared to the front area. These differences in the illumination of the sheet storage area 11 can by detecting the light through the light sensors 6 and a corresponding regulation by the control computer 7 be compensated automatically. This ensures that the lighting impression for the operating personnel in the front and rear of the sheet storage area 11 the same is.

LIST OF REFERENCE NUMBERS

1

 helm

2

 press

3

 connecting line

4

 Abschirmdach

5

 LED lights

5a

 warm white LED lights

5b

 cool white LED lights

6

 light sensors

7

 control computer

8th

 colorimeter

9

 printing material

10

 camera

11

 Sheet deposit area

12

 operating device

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005001417 B4 [0002]
• DE 102010044736 A1 [0003]

Cited non-patent literature

• ISO standard 3664 (2009) [0009]

Claims (11)

Device for enabling visual assessment of print quality by operating personnel with a sheet storage device ( 11 ) for receiving substrates ( 9 ) and a sheet storage device ( 11 ) illuminating, controllable light source ( 5 . 5a . 5b ), characterized in that a sensor device ( 6 ) is present, which the light of the light source ( 5 . 5a . 5b ) at the level of the substrate ( 9 ) and with a control computer ( 7 ), and in dependence on the measured values of the sensor device ( 6 ) the light source ( 5 . 5a . 5b ) by the control computer ( 7 ) is driven. Apparatus according to claim 1, characterized in that the light source from a plurality of light sources, in particular LED lights ( 5 ), and that the light sources are controlled differently by the control computer. Apparatus according to claim 1 or 2, characterized in that the sensor device ( 6 ) Part of a on the sheet storage device ( 11 ) movably arranged color measuring device ( 8th ). Device according to one of claims 2 to 3, characterized in that the light source next to LEDs ( 5 ) in the colors red, green and blue additionally warm white ( 5a ) and / or cool white LEDs ( 5b ) and / or UV LEDs. Device according to one of the preceding claims, characterized in that the sensor device ( 6 ) in or on the sheet storage device ( 11 ) is attached. Device according to one of the preceding claims, characterized in that the device is a camera ( 10 ), which serves for the detection of operating processes of the operating personnel and / or as a sensor device ( 6 ) serving the light of the light source ( 5 . 5a . 5b ) at the level of the substrate ( 9 ) measures. Apparatus according to claim 6, characterized in that the control computer ( 7 ) with the controllable light source ( 5 . 5a . 5b ), the sensor device ( 6 ) and the camera ( 10 ) is in operative connection and that the control computer ( 7 ) emits an optical or acoustic warning if the external light compensation is insufficient and / or the sheet storage device ( 11 ) is to clear for a measurement. Device according to one of the preceding claims, characterized in that standard light values are stored in the device in a memory and that after measuring operations by the sensor device ( 6 ) the measured values are mathematically compared with the stored standard values and the light source ( 5 . 5a . 5b ) is controlled such that the deviations is compensated or at least minimized. Device according to one of the preceding claims, characterized in that in an operating device ( 12 ) the paper type is entered or the paper type by a measurement process with a colorimeter ( 8th ) and, depending on the type of paper, the light type and brightness of the light source ( 5 . 5a . 5b ) by the control computer ( 7 ) is set. Device according to one of the preceding claims, characterized in that in the control computer ( 7 ) the conditions necessary for the assessment of the print quality are stored together with an associated print job, and when the print job is processed, the stored conditions are read out and from the control computer ( 7 ) the light source ( 5 . 5a . 5b ) is set automatically. Device according to one of claims 6 to 10, characterized in that the light source ( 5 . 5a . 5b ) depending on the camera ( 10 ) recorded activities of the operator by the control computer ( 7 ) is turned on and off and / or adjusted.

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