JPH01232077A - Serial printer with detecting function for paper jamming - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to paper jam detection in serial printers.

Conventional technology Traditionally, serial printers obtain driving force from a motor.
One line is printed on the recording paper while the head is sequentially moved one character at a time from left to right, and when the head is moved in the opposite direction and returned to the home position, the paper is fed by one line. When the head returns to the home position, the home switch detects this and sends a signal to turn off the motor, thereby stopping the motor. The operation from starting the motor to printing one line and feeding the paper, stopping the motor, and starting the next one is one cycle. Therefore, by repeating this cycle and printing by changing the lines one after another on the recording paper, the necessary records will be one.
You will be qed.

Problems to be Solved by the Invention However, in this type of printer, the head moves from left to right when printing, and moves in the opposite direction when feeding paper, so if the recording paper somehow moves against the head, If the paper gets caught, it can easily get caught and cause a paper jam. When such a paper jam occurs, even if the head driving motor is in operation (on state), it does not rotate smoothly and even stops rotating. Therefore, the time required for the head to return to the home position is prolonged, or the head does not return to the home position. Note that the motor will not turn off unless the head returns to the home position because the home switch will not be operated. At this time, a large mechanical load is applied to the motor and an overcurrent flows. If left as is, a mechanical load will be applied and overcurrent will flow, causing the temperature of the motor to rise excessively. Therefore, the operator needs to be careful about the paper jam, and if it is discovered, immediately turn off the power and remove it using tweezers or the like. However, if paper jams occur repeatedly, it is not always possible to detect them early, which may shorten the lifespan of the printer, and furthermore, there is a risk that the printer may be destroyed due to the delay in detection.

The present invention has been made by focusing on these conventional problems, and includes a paper jam detection function that can prevent paper jams from shortening their lifespan and destroying them by detecting paper jams early and taking appropriate action. The purpose is to provide a real printer.

Means for Solving the Problems Means for achieving the above object will be explained below with reference to FIG. 1 which clearly shows the present invention.

This serial printer with a paper jam detection function has a timer 5 that reduces the time after the head and recording paper drive motor 12 are started.
4 and a timer reset means 56 that resets the timer 54 after the motor 12 is turned off, a specified time required for printing and paper feeding for one line has elapsed from the time indicated by the timer 54 while the motor 12 is operating. a timer set-up determining means 58 for determining whether the timer 54 has been set up; a timer set-up signal generating means 60 for generating a signal to turn off the motor 12 and indicate a paper jam when the timer 54 is set up; A paper jam indicator 52 is provided to indicate a paper jam.

Operation With the above configuration, the timer set-up determination means 58 determines the time required for printing and paper feeding for one line while the motor 12 is operating from the time indicated by the timer 54 after the start of the head and recording paper drive motor 12. It can be determined whether the specified time has elapsed. Normally, when a specified time required for printing and paper feeding for one line is reached after the motor 12 is started, the home switch is activated and the motor 12 is turned off and stopped. However, when a paper jam occurs, the motor 12 does not rotate smoothly and even stops, so the specified time required for printing and paper feeding for one line elapses while the motor 12 is operating, and the timer 54 is set up. Then, the timer set-up signal generating means 58 turns off the motor 12,
Create a signal to indicate a paper jam. This timer setup signal turns off the motor 12 even if the home switch is not active. Additionally, a paper jam indicator 52 indicates a paper jam. Further, the timer reset means 56 resets the timer 54 when the motor 12 is turned off due to the function of the home switch.

The next line can then be printed.

Example Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 2 is a perspective view showing the internal structure of a thermal dot printer to which the present invention is applied, and FIG. 3 is a cross-sectional view showing the drive circuit and the like. In the figure, 10 is a thermal dot printer, 12 is a head and recording paper drive motor installed on a mounting stand 14, and 16 is a head main body. This head body 16 is an FPC (flexible printed circuit board) that connects to the head unit 18 and each head included therein.
A guide pin 26, which is made up of a support plate 20, etc., and horizontally hung on left and right support frames 22 and 24 fixed to the installation stand 14, respectively;
It is supported by the head feed screw 28. Moreover, the head body 1
6 is fitted into the spiral groove 30 cut on the outer periphery of the head feed screw 28. Further, these guide pins 26, head feed screws 28, etc. are arranged parallel to the surface of the platen 32. Therefore, when the motor 12 is driven, the head feed screw 28 receives the driving force and rotates, causing the head main body 16 to rotate.
is moved along the surface of the platen 32 in the six directions of arrows. At this time, when a thermal head drive signal is applied, each head prints one line on the recording paper attached to the platen 32 while sequentially moving from left to right one character at a time. When one line of printing is completed, the direction of rotation of the motor 12 is always the same, but the pawl of the head body 16 is switched, so the head body 1
6 returns in the opposite direction and simultaneously feeds the paper by one line. When the head body 16 reaches the home position B, the home switch 3
4, the motor 12 is turned off and its rotation stops. These operation signals pass through FPC36 etc.
It is applied from an external drive circuit 38. Note that 40 is a terminal circuit board for operating the printer 10.

This drive circuit 38 is centered around a CPU (central processing unit) 42, includes an amplifier circuit 44 consisting of a transistor array, a motor drive circuit 46, and a tachogenerator waveform shaping circuit 48.
, a printing pulse width control circuit 50, and the like.

Moreover, the CPU 42 has a ROM (read-only memory),
RAM (readable and writable memory), 1. Includes O (input/output port), etc. This CPLJ 42 corresponds to the brain, and executes overall control according to program instructions, performs deception and logical operations, and temporarily stores the results. It also controls peripheral devices. The ROM stores a control program for overall control, a paper jam removal program, print data, etc.

Further, the RAM stores measurement data calculated by the CPtJ42, print data converted from the measurement data, and the like. Furthermore, 1. 0 is the CPU 42, main circuit, etc., and other circuits 44, 46.
Connect with 48.50 etc.

A thermal head drive signal and a motor drive output signal are sent from the drive circuit 38 configured in this manner to the printer 10.
Conversely, a home switch signal and a tacho generator signal are sent from the printer 10 to the drive circuit 38. That is, CPU4
For example, if one word (one data) has an 8-bit configuration, the print data signal output from the transistor array 44
After that, it is converted into 7 glue head drive signals, and 8
The above-mentioned FPC3 including two signal lines (one is a ground line)
6 to each of the seven heads each having an array of heating diodes in the printer 10.

Note that a +5V common power line is connected to each head. Further, the motor control signal output from the CPU 42 is converted into a motor drive signal by a motor drive circuit 46, and is input to the motor 12 in the printer 10. Note that a +5V power line is connected to the motor 12. Conversely, when the head main body 16 presses the home switch 34 from the printer 10, a home switch signal for turning off the motor 12 is input to the CPU 42. Then, a motor stop signal of 25 m5 is output as a motor control signal, and the motor drive signal is turned off. Also, printer 10
The tachogenerator signal @ (TG multiplied signal is shaped by the tachogenerator waveform shaping circuit 48, becomes a timing signal, and enters the CPU 42. Based on this timing signal, the timing for displaying the print data as dots on the recording paper is determined. , a pulse signal according to the head drive signal flows to each head.Incidentally, the tachogenerator
2, the rotational speed of the motor after starting, that is, the position of the head main body 16, becomes clear from the tachogenerator signal. Note that a ground wire is connected to the home switch 34 and the tachogenerator. Furthermore, since the printing pulse width control circuit 50 is connected to the CPtJ 42, it is possible to adjust the pulse width according to the external temperature and change the heat generation time of each head. Therefore, after starting the motor, printing 22...2 characters for one line, and feeding the paper,
If the relationship between the above-mentioned signals is not shown in a timing chart for one cycle from when the motor stops to when it starts the next time, it will be as shown in FIG. 4.

Note that the CPU 42 of this drive circuit 38 has I.

Further, a paper jam indicator 52 consisting of an LED (light emitting diode) or the like is further connected through 0.

Next, the paper jam handling operation will be explained.

FIG. 5 is a flowchart of a paper jam removal program consisting of steps P1 to P8. After the recording paper is installed in a predetermined position of the printer 10, first, the motor drive signal is turned on at Pl, the head and recording paper drive motor 12 are started, and the printer 10 is started. Next, at P2, a timer that measures the time after the motor 12 is started is started. Next, printing for one line is started at P3. Next, in P4, it is determined whether a specified time required for printing and paper feeding for one line has elapsed from the time indicated by the timer while the motor 12 is operating. In the case of No, the process goes to P5 and it is determined whether printing for one line has been completed. Furthermore, in the case of No, the process returns to P3, and printing for one line is performed while repeating each determination in P4 and P5. Normally, when a specified time required for printing and paper feeding for one line □ after starting the motor 12 is reached, the home switch 34 is activated and the motor 12 is turned off and stopped. However, when a paper jam occurs, the motor 12 does not rotate smoothly and even stops rotating, so that the specified time required for printing and feeding one line of paper elapses while the motor 12 is operating. The timer is set up. Then, YES is determined in P4,
Go to P6. At P6, the motor stop signal is turned on for 25 m5 to turn off the motor 12. Further, a signal indicating a paper jam is given to the paper jam indicator 52 to display the paper jam. Therefore, paper jams are reliably detected early and the operating motor 12 is immediately turned off even if the home switch 34 does not work. At the same time, the operator's attention is called to the operator's attention by displaying the paper jam, so that the jam can be promptly removed. If YES in previous P5, P
1 and reset the timer after the motor 12 is turned off. Next, in P8, it is determined whether continuous printing is to be performed. If YES, the process returns to Pl and starts printing the next line. In this way, by repeating printing by sequentially changing lines, a record is created on the recording paper.

According to the present invention described in detail, in order to reliably detect a paper jam at an early stage, immediately turn off and stop the operating head and recording paper drive motor, and further display the paper jam, Shortening and destruction of the serial printer due to paper jams can be prevented, and work efficiency is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a serial printer with a paper jam detection function according to the present invention. FIG. 2 is a perspective view showing the internal structure of a thermal dot printer to which the present invention is applied, and FIG. 3 is a block diagram showing its driving circuit, etc. Figure 4 is a timing chart showing the relationship between each cycle of operation signals necessary for printing one line and feeding paper in the same printer. Figure 5 is a timing chart stored in the ROM included in the drive circuit. 3 is a flowchart of a paper jam removal program.

Claims (1)

[Claims] a timer for measuring time after the head and recording paper drive motor are started; and a timer setup determining means for determining whether a specified time required for printing and paper feeding for one line has elapsed while the motor is operating from the time indicated by the timer. , a timer setup signal generation means for generating a signal to turn off the motor and indicate a paper jam when the timer is set up; a paper jam indicator for receiving the timer setup signal and indicating a paper jam; A serial printer with a paper jam detection function, characterized by comprising a timer reset means for resetting.