1. Field of the Invention
The present invention relates to a photo printer, and more specifically, to a photo printer which is operated with a constant angular velocity, capable of registering the used color of the ribbon, and capable of detecting the amount of the ribbon used.
2. Description of the Prior Art
Along with the development of digital cameras, photo printers, which are able to print photos directly, become popular.
Please refer to
Please refer to
As shown in
Because the controller 30 can determine which dye frame is passing due to different penetrability of each dye frame in the dye region 40, the controller 30 is able to register the positions of the dye frames 32, 34, 36, 38 on the dye region 40 of the ribbon 20 by distinguishing four different sensing voltages. However, the yellow dye frame 32 generates the same sensing voltage with the over-coating dye frame 38. As a result, the controller 30 is required for discerning the order of the other two dye frames (the magenta dye frame 34 and the cyan dye frame 36) to distinguish the yellow dye frame 32 from the over-coating frame 38. The other way is arrange specific bar codes in the front of the yellow dye frame 32 and the over-coating dye frame 38 to distinguish between them. Except determining the amount of the dye region 40 of the ribbon 20, the controller 130 is only able to determine the positions of each dye frame in the dye region 40. After running out of the ribbon 20, if the printer 10 is still used without replacing the ribbon 20, the printer is likely to cease printing in the printing process and bewilder users.
It is therefore a primary object of the present invention to provide a photo printer which is operated with a constant angular velocity, capable of registering the used color of the ribbon, and detecting the amount of the ribbon used, to solve the above-mentioned problem.
According to the claimed invention, a method of registering the position of a ribbon by moving the ribbon with a constant angular velocity and detecting the amount of ribbon used in a photo printer is disclosed. The ribbon includes a plurality of dye regions each having a plurality of dye frames. The ribbon moves in a predetermined direction with a constant angular velocity, and a photo sensor for generating a sensing signal corresponding to the dye frames. The sensing signal has a first status with a low level voltage and a second status with a high level voltage. The method detects the length of time of the first status when the sensing signal changes its status from the second status to the first status. If the length of time of the first status is shorter than a threshold, the first dye frame of the dye region is registered, and the method then determines the amount of ribbon used based on the length of time of the first status. While one of the dye frames of the dye region is finished printing, the method determines the required moving time for the ribbon to register the start position of the subsequent dye frame of the dye region based on the length of time of the first status used to register the first dye frame of a dye region, the total length of the printed part of the dye frame, and the length from a non-printed part of the dye frame to the subsequent dye frame.
These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.
Please refer to
The ribbon 120 comprises a plurality of dye regions 140 in order. Each dye region 140 contains dye frames 132, 134, 136, 138 with different colors, such as the dye frame 132 with yellow; the dye frame 134 with magenta; the dye frame 136 with cyan; and the dye frame 138 being an over-coating dye frame. Each of the dye frames 132, 134, 136, and 138 is equipped with the separation regions 142, 144a, 144b, 144c in the front. The separation region 142 is black, and the other separation regions 144a, 144b, and 144c are transparent without any color. The lengths of the dye frames 132, 134, 136, 138 are much longer than that of the separation region 142, 144a, 144b, 144c. The controller 130 is used for controlling the photo printer 100 in operation in order to count and record the moving time of the ribbon 120. The heat printhead 126 is used for transferring the dye on the ribbon 120 onto the photos. The ribbon 120 moves at constant angular velocity, so that the heat printhead 126 is capable of transferring the dye on the dye frames 132, 134, 136, 138 in order onto a medium to generate a color pattern.
As shown in
Because of higher penetrability of the beam 125 against the yellow dye frame 132, over-coating dye frame 138, and the transparent separation regions 144a, 144b, 144c, a sensing signal with high level voltage is generated while the beam 125 is penetrating these dye frames 132, 138 or separation regions 144a, 144b, 144c. On the contrary, because of lower penetrability of the beam 125 against the magenta dye frame 134, the cyan dye frame 136, and the black bar region 142, a sensing signal with low level voltage is generated when the green beam 125 is penetrating these dye frames 134, 136, or the black bar region 142.
According to the present embodiment, while receiving status of the sensing signal from the photo sensor 124 is changed, the controller 130 records the changed status time Td of the sensing signal and compares the time Td with a threshold time Tth. For instance, while sensing the change of the sensing signal from high to low level, the controller 130 records the time Td in which the sensing signal is in the low level. The region corresponding to the sensing signal with low level is determined to be the black bar region 142 as long as it is detected that the time Td in the low level is shorter than the threshold time Tth. If detecting that the time Td in the low level is longer than the threshold time Tth, it means that the region corresponding to the sensing signal with low level is a magenta or cyan dye frame. At this moment, the controller 130 will ignore the time Td. As long as the controller 130 ensures that the time Td in the low level is shorter than the threshold time Tth, the yellow dye frame in a dye region has been registered. And the amount of the ribbon 120 used is able to be calculated according to the time Td. The details of the determination are as follows.
Please refer to
LB-Bar=RB-Bar-i□□×TB-Bar-i (Equation 1)
Where
Because ω and LB-Bar are constant, and TB-Bar-i=Td. As a result, RB-Bar-I is calculated.
From
πRB-Bar-i2−πRF-Axis2=i×LSet×d
where
Because RF-Axis, Lset, and d are constant, the number of i is able to be calculated wi B-Bar-i from equation 1. The controller 130 is able to determine which of the dye regions 140 the black bar region 142 passing through the photo sensor 124 belongs to. As a result, the number of the consumed dye regions 140 is calculated. After running out one of the yellow dye frame 132, the start position of the magenta dye frame 134 must be registered.
Please refer to
LY-Print is given, which stands for the length the yellow dye Y-Print frame 132 after being printed by the heat printhead 126. Because the heat printhead 126 is on the position 161 shown in
LY-remain=RY-remain×ω×TY-remain-i (Equation 3)
LB-Bar=RB-Bar-i×ω×TB-Bar-i (Equation 4)
TY-remain-i and TB-Bar-i respectively stand for the time it takes for LY-remain and LB-Bar to pass through the photo sensor 124. Because of constant angular velocity,
equation 5 is made by combining equations 3 and 4.
Because the ribbon is very thin, RB-Bar-i is assumed to be equal to RY-remain. As a result, equation 5 is able to be Y-remain simplified as
TY-remain-i=LY-remain×TB-Bar-i/LB-Bar. (Equation 6)
As mentioned before, the controller 130 has measured the time TB-Bar-i in which the ith black bar region passes through the photo sensor, and LY-remain and LB-Bar are known. As a result, the time TY-remain-i, which means the time it takes for the ribbon 120 moving with constant angular velocity to register the start position of the magenta dye frame, is obtained.
Similarly, the LM-Print is given, which stands for the length the magenta dye frame 134 after being printed by the heat printhead 126. And LM-remain which stands for the length from the heat printhead 126 to the subsequent cyan dye frame 136 is calculated by using following equations:
Because the ribbon is very thin, RB-Bar-i is assumed to be equal to RM-remain. As a result,
TM-remain-i=LM-remain×TB-Bar-i/LB-Bar
As mentioned before, the controller 130 has measured the time TB-Bar-i in which the ith black bar region passes through the photo sensor, and LM-remain and LB-Bar are known. As a result, the time TM-remain-i, which means the time it takes for the ribbon 120 moving with constant angular velocity to register the start position of the cyan dye frame 136, is obtained.
Similarly, the LC-Print is given, which stands for the length of the cyan dye frame 136 after being printed by the heat printhead 126. And LC-remain which stands for the length from the heat printhead 126 to the subsequent over-coating dye frame 138 is calculated in the same way as previous mathematical calculations with equations 3-6. As a result,
TC-remain-i=LC-remain×TB-Bar-i/LB-Bar
is concluded. In this way, the time TC-remain-i, which means the time it takes for the ribbon 120 moving with constant angular velocity to register the start position of the over-coating dye frame 138, is obtained, based on LC-remain, LB-Bar, and the time TB-Bar-i in which the ith black bar region passes through the photo sensor.
Each time TB-Bar-i, in which the ith black bar region passes through the photo sensor 124, can be obtained in advance. If lengths of LY-Print, YM-Print, LC-Print are given, the times TB-Bar-i, TY-remain-i, TM-remain-i, TC-remain-i can also be obtained. Such pre-obtained values can be stored in a memory of the printer 100. In this way, if the controller 130 detects the changed status time Td of the sensing signal and compares the time Td with the stored time TB-Bar-i, the amount of ribbon used and start position of each dye frame are easily obtained. Certainly, the controller 130 of the printer 100 can be designed to obtain such values as TB-Bar-i, TY-remain-i, TM-remain-i, TC-remain-i, through above comparison and mathematical calculations.
The above illustrative embodiment uses the green light emitting diode to be the light source as illustration. In fact, the present invention is beyond this limit. Other light sources with various colors for irradiating the ribbon are also used. For example, the red light emitting diode is able to be the light source. When the red light source irradiates the yellow, the magenta, the over-coating dye frames and the transparent separation region, their sensing signal is under the second status. When the red light source irradiates the cyan dye frame and the black bar region, the sensing signal is under the first status. In fact, the light source can be any light emitting diodes with various colors. Because when any light source emits lights against yellow, the over-coating dye frames and the transparent separation region, the sensing signal is under the second status. When any light source irradiates the black bar region, the sensing signal is under the first status. When the any light source irradiates the magenta and the cyan dye frames, the sensing signal is under the first or the second status. In addition, according to the illustrative embodiment, the photo sensor and the light source are set on different sides of the ribbon. In practice, the photo sensor and the light source are able to be set on the same side of the ribbon as long as a reflection device is set at the opposite side for reflecting the beam emitted by the light source to generate corresponding sensing signals.
Please refer to
Compared to the prior art, the present invention printer is able to measure the time in which the black bar region passes through the photo sensor and then, identify the amount of the ribbon used by taking advantage of the operation with constant angular velocity. Therefore, the user is able to know if there are enough dye regions in the dye region of the ribbon. Besides, the present invention is also able to identify the start position of each dye frame by taking advantage of the time for the black bar region to pass through the photo sensor. Consequently, the present invention is not only able to measure the amount of the ribbon used, but also identify the start position of each dye frame to meet the needs of registration without any extra hardware cost.
Those skilled in the art will readily observe that numerous modifications and alterations of the 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.
Number | Date | Country | Kind |
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092122824 | Aug 2003 | TW | national |