Patent Publication Number: US-2006012625-A1

Title: Print system capable of detecting an abnoraml print condition

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a print system capable of detecting an abnormal print condition, and more particularly, to a print system capable of detecting an abnormal print condition according to a physical parameter variation rate.  
      2. Description of the Prior Art  
      In a normal inkjet printer, most of the ink jets are produced by piezoelectric materials and bubble materials. This means that the inkjets have a smaller volume and produce lower noises than a dot matrix printer. This also means, however, that the inkjets generate more heat. Today&#39;s technology often focuses on the heat generated by the inkjets. For example, a prior art temperature sensor feeds back detected temperature of the inkjets to the controller of the print system through an analog-to-digital converter (ADC). This can determine whether the temperature of the print system is higher than a normal temperature range and therefore if the whole print system is able to operate safely. If the temperature of the inkjets reaches the upper limitation of the operation temperature, the controlling end can send an immediate command to stop or slow down the operation of the print system. The quality of the ink drops is improved because the ink drops will not be affected due to excess temperatures. However, if a certain inkjet has too much current because the inkjet is short, the driving circuit of the inkjet becomes overheated because of the excess current. If only detected temperature of inkjets is used for determining whether the operation is stopped or slowed down then, even though the temperature of the inkjets has not reached the upper limitation, it is possible that the driving circuit of the inkjet will still be broken because of the current. Obviously, this situation cannot be detected. Furthermore, because today&#39;s technology focuses only on the heat generated by the inkjets, it ignores the heat generated by other devices (for example, the motor driving device and the power supplying device). Therefore, the whole print system may not operate as well as expected due to the heat. As mentioned above, not only heat generated by the inkjet but also heat generated by other devices should be considered. This can ensure the whole print system is of the highest quality.  
     SUMMARY OF THE INVENTION  
      It is therefore one of the primary objectives of the claimed invention to provide a print system capable of detecting an abnormal printing condition according to a physical parameter variation rate, to solve the above-mentioned problem.  
      According to an exemplary embodiment of the claimed invention, a print system is disclosed. The print system comprises: a print module for printing an image; a motor driving module for driving the print module to print the image; a detecting module for detecting a physical parameter of a component of the print system; and a control module electrically connected to the detecting module for controlling an operation of the print system.  
      In addition, a method for controlling a print system is disclosed. The method comprises: detecting a first physical parameter and a second physical parameter of a component of the print system; utilizing the first physical parameter and the second physical parameter to generate a physical parameter variation rate; and adjusting an operation of the print system according to the physical parameter variation rate.  
      These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram of a print system according to the present invention.  
       FIG. 2  is a flow chart of an operation of the print system shown in  FIG. 1 .  
       FIG. 3  is a block diagram of a detecting module according to the present invention.  
       FIG. 4  is a temperature curve of the print system in a normal condition.  
       FIG. 5  is a temperature curve of the print system in an abnormal condition.  
       FIG. 6  is a diagram of a normal temperature variation rate in each operational mode of the print system. 
    
    
     DETAILED DESCRIPTION  
      Please refer to  FIG. 1 , which is a block diagram of a print system  10  according to the present invention. The print system  10  comprises a printing module  12  for printing an image, a motor driving module  14  for driving the printing module  12  to print the image, and a power supplying module  16  for supplying needed power of an operation of the print system  10  and for supplying needed power of ink drops. This enables the printing module  12  to cooperate with the motor driving module  14  in order to spray the ink drops on corresponding media.  
      The print system  10  further comprises a detecting module  18  for detecting a physical parameter of a component of the print system  10 . The detecting module  18  comprises a first detector  20 , a second detector  22 , and a third detector  24  for respectively detecting the physical parameters of the printing module  12 , the power supplying module  16 , and the motor driving module  14 , where the physical parameters can be voltage, current, or temperature. Therefore, the above-mentioned detectors could be voltage detectors, current detectors, or temperature detectors. The detecting module  18  further comprises an analog multiplexer  26  for receiving the physical parameters detected by the first detector  20 , the second detector  22 , and the third detector  24 , sampling the physical parameters, and selecting to output the physical parameters. In addition, the detecting module  18  further comprises an analog-to-digital converter (ADC)  28  for receiving the sampled physical parameters transferred from the analog multiplexer  26  and for transforming the sampled physical parameters into digital data. The print system  10  further comprises a control module  30  electrically connected to the detecting module  18  for controlling the print system  10 . For example, the control module  30  can control the printing module  12  and the motor driving module  14  so that the printing module  12  can be driven by the motor driving module  14  to spray the ink drops on the corresponding media. Furthermore, the control module  30  can obtain a physical parameter variation rate according to the detected physical parameters of the detecting module  18  and can adjust the operation of the print system  10  according to the physical parameter variation rate. The print system  10  further comprises a memory module  32  for storing a normal physical parameter variation rate. The control module  30  comprises a physical parameter variation rate calculator  34  for receiving data transferred from the ADC  28  and performing a calculation on detected physical parameters of the detecting module  18  to generate the physical parameter variation rate, and a data comparator  36  for comparing the physical parameter variation rate generated by the physical parameter variation rate calculator  34  with the normal physical parameter variation rate stored in the memory module  32 . Here, the control module  30  can adjust the operation of the print system  10  according to the comparison result. The print system  10  further comprises a display module  38  for displaying the operation of the print system  10 .  
      Please refer to  FIG. 2 , which is a flow chart of the operation of the print system  10  shown in  FIG. 1 . The flow chart comprises the following steps:  
      Step  100 : The control module  30  controls the analog multiplexer  26  to select either the printing module  12  or the power supplying module  16  or the motor driving module  14  to be detected;  
      Step  110 : One of the detectors corresponding to the selected device in step  100  (i.e. either the first detector  20  or the second detector  22  or the third detector  24 ) detects the selected device at a first timing to obtain a first physical parameter and transfers the first physical parameter into the analog multiplexer  26 ;  
      Step  120 : The analog multiplexer  26  transfers the first physical parameter and information of the first timing to the ADC  28 ;  
      Step  130 : The ADC  28  transforms the first physical parameter into a first digital data and transfers the first digital data to the physical parameter variation rate calculator  34  of the control module  30 ;  
      Step  140 : The detector corresponding to the selected device in step  100  detects the selected device at a second timing to obtain a second physical parameter and transfers the first physical parameter into the analog multiplexer  26 ;  
      Step  150 : The analog multiplexer  26  transfers the second physical parameter and information of the second timing to the ADC  28 ;  
      Step  160 : The ADC  28  transforms the second physical parameter into a second digital data and transfers the second digital data to the physical parameter variation rate calculator  34  of the control module  30 ;  
      Step  170 : The physical parameter variation rate calculator  34  utilizes a difference between the second timing and the first timing to divide another difference between the second transformation data and the first transformation data to generate a physical parameter variation rate and transfers the physical parameter variation rate to the data comparator  36 ;  
      Step  180 : The data comparator  36  compares the physical parameter variation rate generated by the physical parameter variation rate  34  with the normal physical parameter variation rate transferred from the memory module  32 ; if the physical parameter variation rate belongs to a range of the normal physical parameter variation rate, the operation of the print system  10  is continued normally and the steps  100 - 180  are repeated, and if the physical parameter variation rate does not belong to a range of the normal physical parameter variation rate, proceed to step  190 ;  
      Step  190 : The operation of print system  10  is stopped, and the control module  30  controls the display module  38  to display a message of stopping the operation of the print system  10 .  
      Here, we continue to discuss the operation of the print system  10 . Please refer to  FIG. 3 , which is a block diagram of a detecting module  18  according to the present invention. The analog multiplexer  26  can simultaneously receive the physical parameters, which are detected by the first, second, and third detectors  20 ,  22 , and  24  respectively, generated by the printing module  12 , the power supplying module  16 , and the motor driving module  14 . In this embodiment, physical parameter signals can be amplified by an amplifier and then transferred into the analog multiplexer  26 . On the other hand, the analog multiplexer  26  can receive a selecting signal transferred from the control module  30  and output one of the physical parameter signals of the first detector  20 , the second detector  22 , and the third detector  24  to the ADC  28  according to the selecting signal. In other words, the signal from a selected device is transferred to the ADC  28  for undergoing physical parameter variation rate calculation. For example, if the physical parameter variation rate of the printing module  12  has to be calculated, the control module  30  outputs a selecting signal to the analog multiplexer  26  to select the printing module  12 . The analog multiplexer  26  then outputs the first physical parameter, which is received by the first detector  20  at the first timing, and the second physical parameter, which is received by the first detector  20  at the second timing, to the ADC  28 . Please note that the time interval between the first timing and the second timing can be determined by design demands, i.e. the sampling time interval of the physical parameters can be determined by demands. Furthermore, if multiple physical parameter variation rates have to be obtained, a series of physical parameter signals can be outputted to the ADC  28  under a limitation of a specific time interval in order to calculate the needed multiple physical parameter variation rates. In addition, the analog multiplexer  26  can not only select one of the three physical parameter signals to be outputted to the ADC  28 , but can also transfer two or all three physical parameter signals to the ADC  28 . This depends on the devices needed to calculate the physical parameter variation rate. In this embodiment, the printing module  12 , the power supplying module  16 , and the motor driving module  14  are utilized for an illustration, however other printing devices can have their physical parameters detected. Furthermore, the physical parameters can be temperatures, voltages, or currents.  
      The ADC  28  transforms the first physical parameter into the first digital data, transforms the second physical parameter into the second digital data, and transfers the first digital data and the second digital data to the physical parameter variation rate calculator  34  of the control module  30  for undergoing calculation. The physical parameter variation rate calculator  34  utilizes the difference between the second timing and the first timing to divide the difference between the second transformation data and the first transformation data in order to generate a physical parameter variation rate. The equation is illustrated as follows: 
 
Physical parameter variation rate=(Second digital data−First digital data)/(Second timing−First timing) 
 
      The physical parameter variation rate calculator  34  then transfers the physical parameter variation rate to the data comparator  36 , which then compares the physical parameter variation rate with the normal physical parameter variation rate. If the physical parameter variation rate lies between an upper limitation and a lower limitation of the normal physical parameter variation rate, this represents that the physical parameter variation rate belongs to a range of the normal physical parameter variation rate. Therefore, the control module  30  controls the printing system  10  to continue the operation of the print system  10  normally. On the other hand, if the physical parameter variation rate is higher than the upper limitation of the normal physical parameter variation rate or below the lower limitation of the normal physical parameter variation rate, the control module  30  stops the operation of the print system  10  and controls the display module  38  to display a message of stopping the operation of the print system  10 .  
      Please refer to  FIG. 4  and  FIG. 5 .  FIG. 4  is a temperature curve of the print system  10  in a normal condition.  FIG. 5  is a temperature curve of the print system  10  in an abnormal condition. As shown in  FIG. 4 , when the print system  10  is in a normal condition and peripheral circuits are in a standby mode, the power consumption is at its lowest. The temperature variations of the peripheral circuits can therefore be maintained in a certain range substantially, (here, the temperature variation is shown as a slope in the figure). When the print system  10  is in the printing mode, the temperature of the peripheral circuits increases and is then maintained in a certain range. This is because the ink can only be ejected if the temperature is higher than a certain temperature. The temperature variation rate is theoretically in a normal range. Finally, once the print system  10  has completed the operation the print system comes back to the standby mode. The temperature of the print system  10  returns to the original temperature and the temperature variation rate is maintained. Please refer to  FIG. 5 . When the print system  10  is in an abnormal operation (for example, the device is short or broken), the peripheral devices may have abnormal temperature variation. At this time, the temperature variation rate may be over the normal range. As shown in  FIG. 5 , there are two abnormal temperature variation conditions. If the peripheral devices have an abnormal temperature variation rate, even though the current temperature is normal the device may still be broken. Any sudden rise of the temperature or the current is a sign that indicates the corresponding device may have shorted or broken. This holds true even if the current temperature or current is not high. Therefore, the present invention temperature variation rate can be utilized for preventing the above-mentioned situation. Furthermore, as shown in  FIG. 4  and  FIG. 5 , temperature is detected for calculating the physical parameter variation rate. In addition, the voltage or current can also be utilized for calculating the physical parameter variation rate, and thus omitted here.  
      Please refer to  FIG. 6 , which is a diagram of a normal temperature variation rate in each operational mode of the print system  10 . The corresponding normal temperature variation rates can be set in the memory module  32  according to different operation modes. As shown in  FIG. 6 , in the standby mode, the absolute value of the normal temperature variation rate is less than the value NS 1 . When the temperature rises in the printing mode, the normal temperature variation rate is between the values NS 2  and NS 3 . When the temperature does not vary much in the printing mode, the absolute value of the normal temperature variation rate is less than the value NS 4 . When the temperature decreases in the printing mode, the normal temperature variation rate is between the values NS 5  and NS 6 . Once the print system  10  has completed the printing operation and come back into the standby mode, the absolute value of the normal temperature variation rate is less than the value NS 1 . Please note that the setting of the normal temperature variation rates can be determined according to different operational modes, the detected devices, and the detected physical parameters.  
      Please note that in the present invention, the temperature variation rate can be ignored. That is, even when the temperature variation rate is not calculated, the present invention can still achieve the above-mentioned function. For example, the present invention can directly compare the physical parameters transferred from the first detector  20 , the second detector  22 , and the third detector  24  with normal (theoretical) physical parameters. The present invention can directly compare the first (or the second) physical parameter with the normal physical parameter. The present invention can then utilize the comparison result to adjust the operation of the print system  10 .  
      In contrast to the prior art, the present invention print system can utilize the physical parameter variation rates of each device to ensure each device can operate in a stable operational range. In another situation, if the physical parameter variation rate of one of the devices is over the normal range, the control module reacts according to the above-mentioned situation to ensure that the whole function is not affected. Furthermore, the present invention removes the disadvantage of only detecting the temperature of devices of the print system in order to adjust the print system. The present invention can therefore prevent the devices from broken thereby extending the devices&#39; lives and increasing the whole printing quality.  
      Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.