Patent Application
20200062005
Priority is claimed to European Patent Application No. EP 18 191 042.3, filed on Aug. 27, 2018, the entire disclosure of which is hereby incorporated by reference herein.
The present invention relates to a method for determining wearing of a printing apparatus, to a printing apparatus including a printing mechanism for printing label paper and to a system including a printing apparatus and a computing cloud.
The section introduces aspects that may be helpful in facilitating a better understanding of the invention. Accordingly, the statements of this section are to be read in this light and are not to be understood as admission about what is in the prior art.
A printing apparatus for printing label paper includes a label paper driving mechanism, which is for transporting the printing material. The printing material is a strip of multiple consecutive self-adhesive labels which is wind up to a roll. The roll includes a backing strip, the so-called liner paper, wherein the labels are stuck to the backing strip and are separated from one another. Self-adhesive label paper rolls without a backing strip, the so-called linerless label paper rolls, include a running, adhesive strip of printing material. The label paper roll is unwind in the printing apparatus and transported by the label paper driving mechanism through the printing apparatus to a print head. The print head prints information on the label paper and then, the label is ejected in an eject section of the printing apparatus. For both cases, liner and linerless label paper, the paper is transported by a driven roller, which is a platen roller or a drawing off roller. Further rollers exist for defining the path of the label paper through the printing apparatus. During time and by printing multiple labels, especially driven rollers are subject to wearing and thus need to be replaced from time to time.
A printing apparatus is known from EP1278641B1. The printing apparatus has multiple rollers in a paper driving mechanism. In case of wearing of the rollers, they can be replaced conveniently and without tools by an operator.
The question how to determine if a roller needs to be replaced is not really addressed in the art. Common methods are to replace certain parts of the printing apparatus after a certain time or a certain number of operating hours. As the wearing is subject to the size and quality of the label paper, the quality of the rollers and the printing apparatus itself and other parameters like printing speed and the like, such a time cannot be exactly determined and there is a risk that parts are replaced to early or too late. Other methods are that if the printed image shows some defects, certain parts of the printing apparatus, which are subject to wearing, are replaced. In this case, a number of labels have been printed and do not have an adequate quality.
An embodiment of the present invention provides a method that determines wearing of a printing apparatus. The method includes: controlling a motor of a label paper driving mechanism of the printing apparatus using motor control data; determining a label start indicator; determining a label end indicator; determining a label length indicator corresponding to a length covered by a rotation of the label paper driving mechanism of an unweared printing apparatus between the label start indicator and the label end indicator based on the motor control data; storing the label length indicator; and determining a wearing indicator of the printing apparatus based on stored label length indicators, including the label length indicator.
The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and/or illustrated herein can be used alone or combined in different combinations in embodiments of the invention. The features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following:
Embodiments of the present invention determine and give information about wearing of parts of a printing apparatus, especially about wearing of driven rollers.
An embodiment of the present invention concerns a method for determining wearing of a printing apparatus. The method includes the step of controlling a motor of a label paper driving mechanism of the printing apparatus using motor control data. The method further includes the steps of determining a label start indicator and determining a label end indicator. The label start indicator indicates the start position of a label and the label end indicator indicates the end position of the same label. As the label paper roll as described above includes multiple successive labels, it is understood that multiple label start indicators and multiple label end indicators are determined when a label paper roll is transported through the printing apparatus. In one embodiment, a label start indicator and a label end indicator are determined from sensor signals of different sensors. In one embodiment, a label start indicator and a label end indicator are determined from sensor signals of the same sensor, e.g. a label edge sensor. It is clear to a person skilled in the art that the first indicator which is received is a label start indicator and a consecutive indicator which is received is a corresponding label end indicator. In one embodiment, the label start indicator indicates the start position of a label and the start position of a consecutive label is uses as label end indicator. It is clear that the label end position of the previous label is at a defined distance to the label start position of the consecutive label. The method further includes the step of determining a label length indicator. In one embodiment, the label length indicator corresponds to the length covered by the rotation of the label paper driving mechanism of an unweared printing apparatus between the label start indicator and the label end indicator based on the motor control data, which means between the time a label start indicator is determined and a label stop indicator is determined. In other words, according to one embodiment, if there is an unweared printing apparatus, its behavior of the label paper driving mechanism is known. By applying motor control data to a motor of the driving mechanism, a driven roller is driven. By using the motor control data, the rotation of the driven roller can be calculated. The label length indicator is calculated as a function of this rotation. The label length indicator is a calculated length of paper, which is transported according to the motor control data by a driven roller of an unweared printing apparatus. In one embodiment, the label length indicator is simply the number of degrees the driven roller has turned according to the motor control data. In this embodiment, the transported label length is not explicitly calculated. The label length indicator is stored in the next step. From the stored label length indicators, a wearing indicator of the printing apparatus is determined. In one embodiment, multiple and historic label length indicators are compared in order to determine the wearing indicator.
Wearing of the label printing apparatus and especially of the label paper driving mechanism may have multiple sources. A driven roller like a platen roller or drawing off roller is e.g. made of a synthetic material. During time, this material may harden and therefore its friction coefficient may decrease. Further, abrasion may affect and reduce the diameter of the roller slightly. This may lead to the fact that the paper length transported per rotation of the driven roller slightly decreases during time. Further, the motor is coupled to the driven roller by a coupler, which may be affected by wearing effects.
On the other hand, the motor controller drives the label paper driving mechanism based on an input of a label edge sensor or a blackmark sensor. The motor and the print head are controlled until the label printing is finished. As long as the above mentioned wearing effects are small, they do not affect the printed image. If these effects are too big, the printed image is affected, as the wearing effects cannot be addressed by the motor controller. This means, the control data sent to the print head are correlated with the motor control data, but the label is not transported in a way the motor control data suggest, which worsens the quality of the printed image. Also the calculated label length indicator gives not the real label length but a label length derived from the motor control data, which would be realistic without any wearing. The time which is needed for the transportation of one label is derived from the label start indicator and the label stop indicator. If the same label is transported in the label paper driving mechanism once in a label paper driving mechanism without any wearing and once in a label paper driving mechanism which suffers from wearing, the time between the label start indicator and the label end indicator slightly increases, if the motor is operated by the same speed in both cases. As a consequence, the label length indicator also slightly increases. These label length indicators are stored. By inspecting the shift of the label length indicator during time, a measure for wearing of the printing apparatus is established. Of course, different label lengths have to be taken into account, but as the shift of the label length indicator caused by wearing is much less than the length difference from one label to another, different label lengths can be handled by the method. The above is true for the case that the label length indicator is a number of degrees turned by a driven roller and for the case that a label length is derived therefrom by assuming an unweared system.
According to one embodiment, the label start indicator and the label end indicator are determined by a label edge sensor or a blackmark sensor. The label edge sensor or the blackmark sensor are needed for controlling the printing process. The output of the sensor is used to coordinate the control of the print head. Thus, no additional sensor hardware is needed for the method. The hardware output of the label edge sensor or the blackmark sensor can be reused as input for the method.
According to one embodiment, the printing apparatus has an internal clock and the label start indicator and the label end indicator are time stamps based on the internal clock of the printing apparatus. The internal clock of the printing apparatus may also be a time source provided by an external entity but used by the printing apparatus as internal time reference.
According to one embodiment, the label length indicator corresponds to the number of rotations of a platen roller and/or drawing off roller of the label paper driving mechanism within the time frame between the label start indicator and the label end indicator. It is understood that the number of rotations does not mean an integer number of full rotations of the roller. Rather, it is a measure how much degrees the roller rotated. It is not necessary to calculate a real length from the number of rotations and the diameter of the unweared platen roller and/or drawing off roller.
According to one embodiment, the step of storing the label length indicator includes the step of updating with a determined label length indicator an envelope function representing historic label length indicators of a predefined time interval. It is advantageous to evaluate a statistical value of the label length indicator. Therefore, an envelope function (envelope curve, envelope) is used to reflect multiple label length indictors calculated during a defined time interval to represent a statistic of this measure. It is not necessary to determine and store a label length indicator of each and every label which is printed. Therefore, according to one embodiment, in order to safe computational power, only one label length indicator is determined each minute or one label length indicator is determined for every tenth or twentieth label. To generate an envelope of the label length indicator in the printer reduces storage which is needed to store the label length indicator information. According to one embodiment, the envelope is stored as numeric data, e.g. as a matrix or a vector.
Subject to average use conditions, the printing apparatus is used between three and five hours a day. A platen roller or drawing off roller needs to be replaced after one year. Thus, it is sufficient to generate and store a couple of label length indicators and/or envelopes thereof once a day, or once every couple of days in order to determine the wearing indicator.
According to one embodiment, local maxima of the envelopes are determined.
According to one embodiment, label length indicators are transmitted to a computing cloud or to a server. According to one embodiment, the envelopes are transmitted to a computing cloud or a server. According to one embodiment, the local maxima of the determined envelopes are transmitted to a computing cloud or a server. According to one embodiment, these transmissions are executed on a regular basis, e.g. every day or every week. According to one embodiment, these transmissions are executed as requested by a network.
According to one embodiment, the wearing indicator is determined on the basis of the shift of the label length indicators. According to one embodiment, the wearing indicator is determined on the basis of the shift of the corresponding envelopes. According to one embodiment, the wearing indicator is determined on the basis of the shift of the maxima of corresponding envelopes.
According to one embodiment, the label length indicator, the corresponding envelope and/or the maxima of the corresponding envelope are compared to length data of a data base related to the label. From the label length indicator and the diameter of the driven roller, e.g. the platen roller or the drawing off roller, a real distance which is covered by the roller between the label start indicator and the label stop indicator is calculated. As from the data base a real label length is known, the difference between the distance covered by the roller and the length of the label gives a measure for wearing of the label paper driving mechanism. As wearing effects increase, the difference between the distance covered by the roller and the label length increases.
According to an embodiment of the invention, a printing apparatus is provided. The printing apparatus includes a printing mechanism for printing label paper, in particular in the form of label paper rolls. The printing apparatus includes a print head unit for printing on the label paper, e.g. via thermal direct printing or thermal transfer printing or the like. A label paper driving mechanism of the printing apparatus includes at least a motor and a driven transport roller, in particular a driven platen roller (print roller) or a driven drawing off roller. The printing apparatus further includes a label edge sensor and/or a blackmark sensor. A label edge sensor is able to detect an edge of a label which sticks on a liner paper. In most cases, the same label edge sensor is used to detect a front edge and a rear edge. Alternatively, a separate label edge sensor may be used for detecting the front edge and the rear edge. The label edge sensor detects the edge of the label when the label passes the sensor during transport in the label path of the printing apparatus. A blackmark sensor is a sensor which detects a mark, which is usually a black bar at the edge of the label on the front side or the rear side of the label paper roll. Of course, a blackmark may also indicate the middle of the label. In this case, if the middle of the label and also the label length is known, also the front edge and the rear edge is known. The printing apparatus further includes a processor with at least an input for receiving motor control data and an input for receiving an output of the label edge sensor and/or blackmark sensor. The processor further includes a calculator for calculating a label length indicator. Basis for the calculation of the label length indicator are motor control data and the received signal of the label edge sensor and/or the blackmark sensor. In one embodiment, the label length indicator is a real length of the label. In one embodiment, the label length indicator is a measure which directly corresponds to the label length, e.g. a number of turns of a driven roller which transports the label paper or a number of degrees the driven roller has rotated to pass the label below the label edge sensor from the front edge to the rear edge. The label length indicator for describing the length of the label are calculated on the basis an unweared printing apparatus. This means, no wearing effect is considered when calculating the label length indicator irrespective of the fact if the printing apparatus suffers from wearing or not. The label length indicator corresponds to the length covered by the rotation of the label paper driving mechanism, in particular the platen roller and/or the drawing off roller, when the label paper driving mechanism is controlled by the motor control data between the time of receiving a label start indicator and a label end indicator from the label edge sensor and/or blackmark sensor. As described above, also if a label start indicator and a label end indicator may be the same output signal of the label edge sensor and/or blackmark sensor, it is known if the front edge or the rear edge is detected, as a rear edge always follows a front edge. The printing apparatus further includes a storage for storing label length indicators.
According to one embodiment, the printing apparatus has an internal clock and the label start indicator and the label end indicator are time stamps based on the internal clock of the printing apparatus. The internal clock of the printing apparatus may also be a time source provided by an external entity but used by the printing apparatus as internal time reference.
According to one embodiment, the processor includes an envelope calculator for determining an envelope representing label length indicators calculated during a predetermined time interval and for calculating local maxima of the envelope.
According to one embodiment, the processor further includes a determinator for determining a wearing indicator of the printing apparatus based on stored historic length indicators, envelopes and/or maxima of envelopes.
According to one embodiment, the printing apparatus includes a transmitter for repeatedly transmitting label length indicators and/or envelopes representing label length indicators and/or local maxima of the envelopes representing label length indicators to a computing cloud. In particular, the transmitter is a LAN, WLAN or other network technology which provides access to the internet and/or to a computing cloud.
An embodiment of the present invention further provides a system for determining wearing of a printing apparatus. The system includes at least one printing apparatus as described above. The system further includes a computing cloud. The computing cloud includes at least one data storage unit which includes at least one memory device. The memory device is configured to store instructions and data. The computing cloud further includes at least one computer processing unit configured to execute the instructions which are stored in the at least one memory device. The computing cloud is configured to receive label length indicators and/or envelopes representing label length indicators and/or local maxima of envelopes representing label length indicators. The computing cloud is configured to detect shift of the received label length indicators and/or the received envelopes and/or the received local maxima. The computing cloud is further configured to determine a wearing indicator of at least one printing apparatus based on the detected shifts. The computing cloud is further configured to instruct at least one client device associated with the computing cloud if the wearing indicator reaches a first threshold and/or the deviation of the wearing indicator reaches a second threshold.
Embodiments of the present invention are described below in relation to the drawings. The description and drawings merely illustrate principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
A first envelope 30, 31, 32 representing the label length indicators determined during a first time interval and a second envelope 36, 37, 38 representing the label length indicators determined during a second time interval are shown. The first section 30 of the first envelope represents label length indicators that were determined during a first time interval when a first label type E1 was printed. The second section 31 of the first envelope represents label length indicators that were determined during a first time interval when a second label type E2 was printed. The third section 32 of the first envelope represents label length indicators that were determined during a first time interval when a third label type E3 was printed. The label length L of the third label type E3 is the longest, the label length L of the first label type E1 is the shortest. The first section 36 of the second envelope represents label length indicators that were determined during a second time interval when a first label type E1 was printed. The second section 37 of the second envelope represents label length indicators that were determined during a second time interval when a second label type E2 was printed. The third section 38 of the second envelope represents label length indicators that were determined during a second time interval when a third label type E3 was printed. Each section 30, 31, 32, 36, 37, 38 of an envelope has a corresponding (local) maxima 33, 34, 35, 39, 40, 41. The maximum 39 of the first section 36 of the second envelope representing label length indicators that were determined during the second time interval when the first label type E1 was printed is shifted by a distance d1 to the right on the x-axis compared to the maximum 33 of the first section 30 of the first envelope representing label length indicators that were determined during a first time interval when the first label type E1 was printed. This shift of the maximum 33, 39 between the first time interval and the second time interval in x-direction to the right indicates that the platen roller or drawing off roller needs more turns (more degrees of rotation) to transport a label of the first label type E1. From this, it is clear that in the second time interval more wearing is present in the printing apparatus than in the first time interval. The same result is discovered when the distances d2, d3 between the maxima 34, 40, 35, 41 of the first time interval and the second time interval with regard to the other two label types E1, E2 are evaluated.
The functions of the various elements shown in the Figures, including any functional blocks, may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, the functions may be provided, without limitation, by digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), and non volatile storage. Other hardware, conventional and/or custom, may also be included.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those of ordinary skill within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below. Additionally, statements made herein characterizing the invention refer to an embodiment of the invention and not necessarily all embodiments.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18 191 042.3 | Aug 2018 | EP | regional |
