The main fault of the printer detection and repair
1, out of paper detector (PE detector)
The detector for the optical coupling device, installed in the feed slot, the printer function is to detect whether the current paper. When there is paper, the light-emitting diode light reflected by the paper, get photocell, it turns on, the +5 V signal to the CPU issue. If the user is not on paper or paper to the printer has been exhausted, LED light can not reach optical tube, so close, OV signal sent to the CPU, users receive a buzzer and warning lights of paper.
Out of paper detector is very easy to make mistakes, but generally very easy to solve, in the STAR Universal printer, the detector LED is generally smooth surface and by up to a certain point of view to place, easy covered with dust, blocking transmission of light paper, resulting in optical control constant for the closing. Here's one case of failure.
Failure phenomenon: a AR3200 printer, into the paper, every time only a few centimeters on the paper. Continuous by [wrapping paper / paper back / out of paper] key, although available on paper, but to press the paper does not lift rod, line is not on, the printer still reports out of paper.
First of all, AR3200 printer into the paper process is as follows: (1) short into the paper, paper delivered to the top of paper detector, detector paper confirmed after the next process, if the detector that no paper feed end action. (2) grow on paper, press the paper shot up, according to the first empty set of paper to print the paper sent to the location, online ready to print. In this failure, it is clear the implementation of the process repeated (1), which judgment-free paper as the printer end, it is not on-line printing. Failures are clarified, the rest of the work also is very simple, clean can be. Note that non-horizontal push STAR printers, in general, need to remove the rear cover can wipe, and then take the paper should be converted into a chain, expanding roller and the distance between the detector to operate.
Note that the detector false positives out of paper, not necessarily because the error detector itself caused. Use of color or character of the printing paper has been able to absorb more light, it will also lead to optical tube does not fully turn, use can not be online. At this time the general has the following three ways to choose:
(1) modify the EDS settings to detect invalid out of paper (see random manual setting method). The printer will print an unconditional on-line, regardless of whether the paper. However, this has a drawback is that when the user exhausted paper, the printer will also continue to be meaningless rubber roller on the print. Therefore, the user is generally not recommended to use this feature.
(2) find a way from the hardware, test paper from the optical signal-to-ground resistance of the transistor removed. To meet the signal is weak, can replace the resistor, replaced with a larger resistor values. +5 V power supply to improve its on the partial pressure, increase the signal value. This optical tube fully on, there are large current through the resistor has a higher signal value is same.
(3) STAR printer for new users, there is another option, is to make software changes. For example AR6400 printer, you can DOS QBASIC language changes under the EEPROM, so that the printer to adapt to weaker signals.
Second, press the paper lever position sensor
The detector is a mechanical switch. When the pressure down on paper when the switch lever to open, send +5 V signal; pressure rises when the switch is closed bar paper issued OV signal. Press the paper into the paper at the beginning of bar lift, feed the end of fall, if the user set in the EDS 1 / 6 inch sheet of paper blank, press the paper lever will remain for some time and then fall in the print process. If the rod can not place pressure on paper, printer error crash. Here are examples of a failure.
Failure phenomenon: a AR3200 printer, press the paper into the paper when the lift rod, the rack on the left the noise and then freezes.
AR3200 and AR3200 + type printer does not require special relays, but through a complex series of gear operation is complete, press the paper lever action. Specifically, it is when the characters in the feed rack car crash left the spring, push rod driver gear to press the paper left, and take the paper motor gear contact, then take the paper motor to drive the lever to press the paper to make it in place. Then the word car shifted to the right, stretching the spring, drive gear and motor gear disengagement take paper, press the paper lever to stop movement. This printer has been damaged gear, drive gear does not bring the paper-bar pressure, friction noise, due to press the paper detector bar can not be found in place, so that the printer freezes. Fault disappears after changing gear.
Third, adjust rod position detector Feed
The detector is a mechanical switch means for monitoring the user the choice of feed. When the user uses friction feed means, through the feed lever to adjust the switch is closed, OV signal sent to the CPU. On the contrary, if the user mode using the feed chain, then the switch is turned on, the +5 V signals to the CPU. Once the deformation of the switch, also will report the wrong signal.
