JPH0354638B2 - - Google Patents

Description

[Detailed Description of the Invention] <Field> The present invention relates to a printing device, and particularly to a printing device such as an impact line printer, which generates noise during printing operation in printing mode and in which movable parts such as a type belt rotate continuously. This invention relates to an interlock control method for a printing device, in which an interrupt interlock is applied continuously to the opening and closing of a cover of a casing to prevent printing and to stop a movable part at least when the cover is fully open.

<Prior art and background> These printing devices are usually housed in a cover housing that also serves as soundproofing, and require operator intervention such as replenishing and removing paper, or adjusting the print and paper length format while viewing the print output. When printing, open the cover and operate the device, but if printing is in progress, it will make noise, and even when not printing, when changing the ribbon or converting the type belt, it is dangerous if the type belt is running, so it is necessary to stop it. However, type belt drive systems are usually designed to have a large inertia in order to stabilize the speed, so even when the switch is turned off, it does not stop easily, resulting in a loss of time.

As a countermeasure to the above, if we consider installing a status switch that detects the cover opening in conjunction with the cover opening operation, which must be opened in case of operator intervention, and stopping the motor drive when the cover is opened, there will be no problem while printing is stopped. If the motor is currently being printed, directly turning off the motor in response to the condition has the disadvantage that it cannot guarantee the normal completion of printing, and this is one of the control tasks of the microprocessor that is in charge of logic control. If such alarms and security monitoring are entrusted to the same level as other tasks, the monitoring check system and the execution system on the monitored side will have the same level of reliability, which is not very interesting as a monitoring system, but it is more reliable as a system. Another problem was that it was not worth having a microprocessor.

<Purpose and Features> In view of the above, the purpose of the present application is to run the monitoring system as a control program in the same microprocessor with the same level of reliability as the execution system in normal cases, but to monitor the time for predetermined items. It is an object of the present invention to provide a duplicative printing device by having a means and an instruction operation means from the means, and a feature of the present invention is that in order to achieve the above object, the printing device is mounted in a cover casing, and the printing device is mounted in a cover housing, and the printing device is installed in a cover housing, A printing device comprising a state detection means for detecting a state, and a control means for interrupting operation of the printing device in response to an open state signal of the state detection means, the control means being provided as the control means and configured to control the logic of the printing device. A first control means that operates via the control unit and controls the printing device to enter a stop mode immediately after completing one line of printing when the printing device is printing, and to cut off power supply to the movable portion to stop the printing device. and a second control means for directly cutting off the power to the movable part after a certain period of time longer than the one-line printing time, and the first The invention is characterized in that the control means is activated, and the second control means is also activated without being involved in the operation of the first control means.

<Embodiment> The figure is an explanatory diagram of an embodiment of the present invention, and shows a circuit diagram around the drive of a type belt traveling motor of a printing device.

As is clear from the diagram, the belt running motor 1 is a periodic or induction motor driven by a commercial frequency AC power source, and the relay contact is turned on during operation.
rl ₁ and rl ₂ are connected in series and control the power supply to the belt traveling motor 1 in a double manner.

On the other hand, interlock switch SW ₁ monitors the opening/closing status of the housing cover, and turns off when it is closed and turns off when it is open.
It becomes ON. The MPU2 is a logical control circuit for the printing device, and is connected to a higher-level device via an interface circuit (not shown in the figure), and performs printing for data acquisition, verification, printing, etc. based on control commands from the higher-level device. A device that controls the operation of each part of the printer, and also controls the operation of each part of the printer under control based on status signals and mode signals from each part of the printer, as well as operator operation signals from the operation panel. The drive stop control of the belt running motor based on the key is also one such control.
Based on the belt running motor control signal a created from the MPU2 under conditions such as [no print command] * [To time has elapsed since there was no print command] or [belt running motor stop] I turned off relay RL2 via transistor 3, opened RL ₂ , and stopped the pelt drive motor 1. However, although this allows fine-grained control, it is controlled by a program, so it can cause problems such as hardware failure of MPU2, incorrect execution of the program, etc. In addition, reliability compensation when viewed as a monitoring device due to delays caused by other failures, etc. is insufficient, so in the present invention, a dedicated monitoring circuit for such cases is replaced with such a logic system.
By having it together with the one via MPU2,
This means that a means is also provided to disconnect the drive power supply by rl ₁ after a predetermined period of time (independently of the status output condition on the logic system side), and relay RL1 is used.
Then, by holding the current up to the turn-off ampere turn with a time constant determined by the slow recovery capacitor _C1 and the internal resistance Ro of the coil of relay RL1, the current is passed through transistor 4 after switch SW1 turns off (cover open). The condition input for outputting output a to MPU2 is entered, but for a predetermined time relay RL is input.
Since the operation of step 1 is delayed and rl ₁ is kept ON, if the predetermined time T ₁ is set longer than the one-line printing time of the printing device, normally the output a from now on, that is, the stop condition on the logic side. Even if the cover is opened during one line printing, the printer will stop normally by disconnecting rl ₂ , but even if this does not work,
By disconnecting rl ₁ , the power supply to the belt running motor 1 can be cut off.

Regarding the relationship between the opening degree of the cover and the operating point of switch SW1, the turning point of switch SW1 is not placed between the fully closed cover and the partially closed cover, but is set between the fully open and partially closed cover. By placing the paper in the open position, it is possible to continue printing in a half-open state. When handling format paper, adjustments such as horizontal alignment of the paper and vertical alignment between the print line and the marked line can be made in almost the same way as before. It can be executed.

<Effects> As explained below, in the present invention, the stop circuit on the logic side is covered and the motor is directly stopped after a predetermined time without going through the MPU 2, so it is possible to perform fine stop control using the logic side, and it also solves the problem of lack of reliability. Since this can be supplemented by a direct stop means that is operated later, it is possible to provide a printing device that can perform motor stop control that is both serviceable and reliable.

[Brief explanation of drawings]

The figure is an explanatory diagram of one embodiment of the present invention. In the figure, 1 is a motor, 2 is a microprocessor (MPU) that controls the printing device, 3 and 4 are transistors, and SW ₁ is an interlock switch RL ₁ on the cover. RL ₂ indicates a relay, and RL ₁ and RL ₂ indicate the output contacts of each relay.

Claims (1)

[Scope of Claims] 1. A state detection means that is mounted in the cover housing and detects whether the cover is opened or closed, and which interrupts the operation of the printing device in response to an open state signal from the state detection means. In a printing device having a control means, the control means is provided as the control means, operates via a logic control section of the printing device, and when the printing device is printing, it enters a stop mode immediately after printing for one line is completed. and a second control means that directly cuts off the power supply to the movable part after a certain period of time longer than one line printing time; The first control means is actuated by an output generated by the detection means which detects that the cover is opened by a predetermined width or more, and the second control means is also actuated without being involved in the operation of the first control means. A printing device characterized by: