JPH0372474B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a confirmation control method for a printing device used in a calculator or the like.

A type wheel with printed characters such as numbers and symbols formed on its outer periphery is rotated by a motor, and the position of the type wheel is determined by a timing pulse generated corresponding to the typed characters and a reset pulse generated once per rotation of the type wheel. In a conventional printing device that performs detection and then prints, the printing operation is performed immediately after detecting the reset pulse to print on recording paper.

This control method is effective if the reset pulse is used by a detector that does not generate erroneous signals, such as a photodetector or a magnetic detector, but chattering and bouncing always occur with mechanical contacts that require low cost. In addition, foreign matter such as dust sometimes causes poor contact, and the reset pulse may not be generated during normal operation. As described above, if the reset pulse is not generated at the normal position, there is a drawback that printing errors occur.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, it is an object of the present invention to provide a printing device that can perform normal printing even if an abnormal reset signal occasionally occurs.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a block diagram of an embodiment of the present invention. In the figure, the PCU is 1 chip in a normal calculator.
This is an arithmetic processing unit made up of LSi, and mainly consists of the following items.

That is, there is an arithmetic unit AC, which is composed of adders, judgment circuits, etc., and M, which performs calculation processing of the calculator and print control of the present invention, stores data input to the calculator and calculates the number of timing pulses. This is a storage unit consisting of a counter for counting, FF for storing flag information, etc. These usually consist of RAM (Random Access Memory). Next, there is a storage unit R that stores information for controlling the calculation unit AC and the storage unit M. This is read-only memory (ROM)
The instruction decoder and the like store at least the control information of the present invention as shown in the flowchart of FIG.

S is a detection circuit for detecting timing pulses and reset pulses from the printing section P.

P is a printing section, which is mainly composed of the following.

D is a type ring with type formed on the outer periphery.
MO is a motor for rotating the type wheel, and SO is a solenoid for driving the hammer H.

The TC is a code plate that generates pulses corresponding to the type by the rotation of the type wheel, and holes are provided at positions corresponding to the type.The light from the lamp L passes through the code plate TC, and the light is is a phototransistor
The light is received by HT and the timing pulse TP is input to the PCU section.

As shown in the figure, RC is a code plate that generates a signal once per rotation of the type wheel D on which a conductive pattern PC is formed, and is grounded via the contact piece GS by contact of the conductive pattern PC of the contact piece RS. , reset pulse
Generates RP and inputs it to the processing unit PCU.

D ₂ and D ₁ are drive circuits for driving the motor M and the hammer solenoid H, respectively.

Figure 2 shows the timing pulse TP from the printing section P.
and a timing chart of reset pulse RP.

In the figure, A is a timing chart when the reset pulse RC is normally output.

The figure below is a timing chart when the first reset pulse RP is not output normally.

C is a case where the first reset pulse RP was output normally, but the second reset pulse was not output normally.

The operations of the above three methods A, B, and C will be explained according to the flowchart shown in FIG.

When the motor MO is first driven and the type wheel D rotates, a timing pulse TP is output, so
The “TP=1” judgment instruction is executed, and TP becomes 1.
Otherwise, the execution of the "TP=1" instruction is repeated until TP becomes 1. When the TP pulse comes, "TP = 1" becomes YES, and "RP = 1"
The determination instruction is executed. Therefore, the "TP=1" command without the reset pulse is repeated until the TP pulse becomes "0", and when it becomes "0", the "TP=1" command is executed again until the TP pulse rises. Ru. If "TP=1" becomes YES, "RP=1" is executed, and if there is an RP pulse, "TPC=0" becomes YES and is executed.
This is a counter that counts TP, and it counts the number that corresponds to the number of printed characters, and in this case, it is 0.
It is a decimal counter that automatically resets to ``0'' when it counts up to 11 and reaches ``12.''
The contents of this counter are reset to "0" by execution of . This is the timing chart
This is the TPO timing pulse.

The next "TP=1" command is repeated until it becomes NO, and then the rising edge of TP is detected by the "TP=1" command. Until now, when the rising edge of TP is detected, the "TPC+1=TPC" command is executed, and the TPC counter content is incremented to "1".

The TPC content becomes “11” due to the next “TPC=11”
It is determined whether or not, and since it is NO, the next “TPC=
0” determines whether the TPC content is “0” or not.
Since it is NO, the same command as the previous one is executed. By repeating this, the timing pulse TP
Each time , the contents of the counter TPC are incremented by "+1".

With the instruction that the content of the counter TPC becomes "11", the process advances to YES, and the "TR=1" instruction is executed. There is no PR signal at TP ₁₁ in Figure 2 A, so it goes to NO and executes "TP=1" again, and when the next "TP=1" comes a TP pulse, "TPC+1=TPC" is executed and TPC
Since the counter is in decimal, 11+1=0, and the TPC counter becomes "0". In the next one, it is NO, and in “TPC=0”, it is YES, and the next “TR=1” instruction is executed, and in Figure 2 A, RP
Since is 1, the process advances to YES and the correct printing operation is performed. As above, reset pulse
At the first TPO after the RP starts up, the TPC counter becomes "0" and a correct counting operation corresponding to the type wheel D is performed, and normal correct printing is performed.

Next, the case where the portion of the reset pulse indicated by the dotted line in FIG. 2B is not output will be described.

When each command in the flowchart in Figure 3 is executed and repeated in the same way as the previous time, it advances to YES with "RP = 1", and "TPC = 0".
is executed and the contents of the counter TPC are reset to "0", which means that the position of TP ₁ is incorrectly detected (TPO) rather than the correct position of TPO.

The subsequent instructions are executed, the next instruction is repeated, and the timing counter TPC is incremented in synchronization with the TP pulse. Then proceed to YES with the command when TPC = 11,
"RP = 1" is executed, and as is clear from the diagram, (TP ₁₁ ) is originally TP ₀ , but since the RP pulse exists, it moves in the direction of YES, and the next "FER = 1" is It will be judged. This FER is an error flag, and currently this flag is "0".
The error flag is set to "1" when "FER=1" goes towards NO. Next “TPC=
0'' command resets the contents of TPC=11 to ``0'' and corrects the TP position. After that, the correct printing operation is performed repeatedly in the same manner as in the case of A and A.

Next, an explanation will be given of the operation when the reset pulse RP shown in FIG. 2C is not output normally for the second time.

YES if "RP=1" indicates that the command in the flowchart in Figure 3 will be repeated in the same way as the previous time.
The counter is reset when "TPC=0" in the direction of . Then the command is repeated,
When the TPC counter is incremented and becomes TPC = 11, the process advances to YES, and "RP = ₁ " is executed.
Proceeds to , is executed, TPC=0
Therefore, the next "RP=1" is executed. At this time, as shown in Figure C, RP is not output and progresses in the NO direction, and the error flag FER is determined.
The flag FER is set with "FER=1",
Processing is performed to confirm the RP once again.
In other words, "TPC = 0" is executed, but since TPC is originally 0, the following is repeated, and when TPC = 11, is executed,
Next is executed, and the RP at the time of TPO is determined by "RP = 1", but it will be correct from now on.
Since the RP pulse is being output, correct printing is performed by the printing operation that advances toward YES, and the error flag FER is set to "0" at the next "FER = 0".
and exit.

YES with "FER=1" occurs when an abnormal waveform of the RP pulse occurs twice in a row, and in this case, the printing operation is terminated without performing the printing operation as an error state.

As is clear from the above explanation, according to the present invention, even when the reset pulse RP is not output normally, the correct reset pulse is detected, and an extremely reliable printing device that can perform normal printing at any time is realized. can.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
Figures A, B, and C are timing charts for explaining the operation, and Figure 3 is a flow chart showing an example of control according to the present invention. PCU...Arithmetic processing unit, S...Detection circuit, RS,
GS...Touch piece, RC...Code plate, D...Type wheel.

Claims (1)

[Scope of Claims] 1. A type wheel having a plurality of type characters such as numbers and symbols formed on the outer periphery, a motor for rotationally driving the type wheel, and a timing pulse corresponding to each type by rotation of the type wheel. In a printing device having a reset pulse that is generated once per rotation of the type wheel and a timing generation circuit that generates the reset pulse, the timing position of the reset pulse is checked, and if the reset pulse is not in the normal position, a checking operation is performed again. and means for executing a printing operation if the reset pulse is at a normal position as a result of the reconfirmation operation. 2. The printing device according to claim 1, wherein if the printing device is not in the normal position in the reconfirmation operation, an error state is set.