JPS6328796B2 - - Google Patents

Abstract

PURPOSE:To character which has been printed is read immediately and the read result is compared with the print input signal; when a print miss is detected, a carriage is automatically returned to its original printing position to print the same character again, thereby attaining rechecking afterward.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer as a terminal device.

Conventionally, no printer of this kind has been developed that reads printed characters with a character reader immediately after printing and automatically verifies whether or not the intended characters have been printed. A printer with a front inserter that attaches a single-bit optical detection element to a movable scanning part such as a carriage, detects a previously printed specific mark with the optical detection element, and sets the next line to be printed. , printers are known that use detection elements similar to those described above to detect lines on forms, etc. when they are scanned in the horizontal direction by a carriage, etc., making it possible to perform an automatic tab set function. It goes without saying that the printer according to the present invention is different in nature in that it has no concept of print verification.

As a conventional printer incorporating the concept of print verification, for example, the one shown in FIG. 3 is known.

FIG. 3 is a block diagram showing a print check method in a conventional printer. In Figure 3,
Reference numeral 7 designates a print command generating section, 2 a circuit for instructing the amount of movement of a type wheel, 3 a print wheel driving and printing circuit, 4 a character wheel, 5 a wheel clock counter, and 6 a coincidence determination circuit.

First, when a command to print a desired character is issued from the print command section 7, the type wheel movement amount instruction circuit determines how far the type wheel should be rotated from its reference position in order to print the desired character. It is determined whether printing should be performed based on the position, and the rotation amount is instructed to the character printing wheel drive and printing circuit 3, and is also sent to the coincidence judgment circuit 6. When the printing wheel drive and printing circuit 3 receives the required rotation amount signal from the circuit 2, it rotates the type wheel 4 by the required amount of rotation in response to the signal and then performs the printing operation, so that the desired characters are printed. It turns out. When the printing operation is completed, the type wheel 4 must return to its original reference position to prepare for the next printing command. When the type wheel 4 rotates for this return, it generates a wheel clock pulse, which is counted by the wheel clock counter 5 and the resulting count value is sent to the coincidence judgment circuit 6. The coincidence judgment circuit 6 compares the information signal coming from the circuit 2 and the information signal coming from the circuit 5, and if they match, it is judged that the desired character has been printed correctly, and if they do not match, a printing error has occurred. and outputs a yes or no signal accordingly.

In such a conventional print check method, if the type wheel movement amount indicating circuit 2 and the wheel clock counter 5 each cause the same error by a corresponding amount due to external noise, etc.,
Even though the characters instructed to be printed and the characters actually selected and printed on the type wheel 4 do not match, the match determination circuit 6 cannot output an error signal. Furthermore, in the conventional checking method shown in Fig. 3, even if the selection of printing characters by rotating the type wheel 4 is checked correctly, there are hammer movements, ribbon movements, etc. before the characters are actually printed. If the operation is not normal, printing will not be performed correctly. Conventionally, there has been no system that has a check circuit for all of these operations, and in particular, no system that has taken into consideration the automatic check of the density of the ink on the ink ribbon.

Therefore, an object of the present invention is to provide a serial printer that makes it possible to compare characters instructed to be printed and printed characters.

Next, this invention will be explained in detail, but before that, an example of a character reader used in an embodiment of this invention and its mode of operation will be explained with reference to FIGS. 1 and 2. .

FIG. 1a is a top view of the platen and carriage in the printer, and is an enlarged partially cutaway view to show the state in which the optical character detection unit is attached to the printer carriage, and FIG. 1b is a front view of the paper guide, and is a diagram for more clearly showing the attachment location of the optical character detection section. Note that the relative relationship of dimensions in the figure is not accurate because this figure is only intended for easy understanding of the arrangement of the main parts.

In FIG. 1, 30 is a platen, 31 is a printing paper, 32 is a paper guide, 33 is an opening in the paper guide, 34 is an ink ribbon, 4 is a type wheel, 36 is a hammer, 37 is a type selection motor, and 38 is an opening in the paper guide. 39 is a shaft, 1 is an optical character detection section, and A to O are optical sensors.

In FIG. 1a, the paper guide 32 is shown to be located midway between the front surface of the carriage 38 (the position of the ink ribbon 34) and the printing paper 31, but this is for the sake of clarity. In reality, the paper guide 32 is integrally attached to the carriage 38, and when the carriage 38 moves in the left-right direction on the shaft 39, it moves in the left-right direction together with the carriage 38. As can be seen from the figure, the carriage 38 includes a type selection motor 37.
A hammer 36, a type wheel 4, an ink ribbon 34, and a paper guide 32 are mounted. Printing is accomplished by driving the hammer 36 and striking the type wheel 4, causing the type to impinge on the paper 31 on the platen 30 through the ink ribbon 34 and the aperture 33 in the paper guide 32. The paper guide 32 moves together with the carriage 38 to guide the surface of the paper 31 to be printed, and has an opening 33 through which the hammer 36 is inserted. It is ejected toward paper 31 so that printing can be performed. When one character has been printed, the carriage 38 moves to the right on the shaft 39 by one character's space, prints there, and then sequentially moves further to the right and prints the paper 3.
After reaching the rightmost end of paper 3, the carriage 38
It returns to the leftmost position of 1, and from there it moves to the right again, printing one character at a time. Therefore, for example, if the optical character detection section 1 is attached to the left edge of the opening 33 of the paper guide 32 as shown in the figure, after the hammer 36 prints on the paper 31 through the opening 33, When the carriage 38 moves to the right by one character's space, the optical character detection unit 1 also moves one character to the right together with the carriage 38, so that it detects the character that has just been printed on the paper surface of the paper 31. Scanning can be performed by optical sensors A to O in section 1.

FIG. 2 is a diagram for explaining a character reading operation of an optical character detection section attached to a horizontal scanning movable part such as a carriage of a printer. In FIG. 2a, 1 indicates an optical character detection section, and the detection section 1 is equipped with five optical sensors A to O, as an example. When the detection unit 1 moves to the right by a distance P (a space for one character), the five sensors A to O complete the reading scan of the character D. Figure 2b shows each sensor during the above-mentioned scanning.
FIG. 2 is a diagram showing read waveforms output by each
Each sensor outputs an output when scanning a character-shaped part, and takes a non-output state when scanning a blank part of the paper that does not correspond to the character-shaped part. _VH and _VL
indicates the threshold value used when digitizing the output of the sensor. When the output level is higher than V _H , it is expressed as a logic 1 indicating that there is a printed area, and when it is below V _L , it is expressed as a logic 0 indicating that there is no printing. It is expressed as If there is an output level between _VH and _VL , this is considered to be a half level. FIG. 2c is a diagram in which the output waveform of the sensor shown in FIG. 2b is read using sampling pulses and digitally stored in memory, and each square represents the capacity of 1 bit. A white square indicates no printing section, logic 0, a double hatched black grid indicates presence of a printing section, logic 1, and the shaded area indicates half level. The diagonal part of this half level is logic 1
In a memory that has only binary levels of 0 and 0, it may be treated as either level, but when using it as a standard for comparison with others, it is necessary to ignore it and not use it as a standard. .

Now that an example of a character reader and its mode of operation have been clarified, a description will be given of the printing error checking system which is the premise of the present invention, with reference to FIG.

FIG. 4 is a block diagram of a printing error check system which is the premise of this invention. In Figure 4,
16 is a print command generation unit, 17 is a lateral movement circuit,
8 is a printing wheel movement amount indicating circuit, 9 is an AND circuit, 10 is a printing wheel driving and hammer operation circuit, 12 is a printing paper, 13 is a printing pattern decoder, 14 is a digitizing memory, 15 is a coincidence judgment circuit, and 18 is a An optical detection circuit is shown.

First, it is assumed that the print command generation section 16 issues a print command for the letter D in response to an external command. Then, this command signal is delayed by one print cycle required for the printer to print one character (the delay circuit is not shown) and enters the print pattern decoder 13, which decoders the character D. When a print command signal is received, a digital signal is outputted in response to the print command signal, and the second
Digital information of the letter D as shown in FIG. c is stored. That is, in FIG. 2c, the white squares are stored as logic 0, the double hatched black parts are stored as logic 1, and the diagonal squares are stored as either logic 1 or 0, as appropriate.

On the other hand, the print command signal issued from the print command generation section 16 enters the lateral movement circuit 17, and the circuit 17 moves the carriage of the printer in the lateral direction by one character to print the current print from the previously printed character position. move the blank paper to the new printing position where it should be printed. Next, the print command signal is sent to the print wheel movement amount instruction circuit 8.
The circuit 8 then determines how much the type wheel 4 should rotate from its reference position in order to print the letter D, and sends the rotation amount signal to the AND circuit 9. to the print wheel drive and hammer operation circuit 10. This circuit 1
0, upon receiving the rotation amount signal, rotates the type wheel 4 by the required amount and then operates the hammer, so that the required character D is printed on the printing paper 12.
is printed on the paper.

Next, when the print command generation unit 16 issues a print command in response to a second external command, this command signal is transmitted to the lateral movement circuit 17 as before, and this circuit 17 moves the printer's carriage in the lateral direction by one character. , and move it from the position of the previously printed character D to the new printing position of the blank paper to be printed this time. At this time, the optical character detection section 1 is attached to the carriage of the printer and moves in the horizontal direction, so the optical sensors A to O in the detection section 1 scan the printed character D. I will do it. The optical detection circuit 18 thus detects the letter D scanning signal (FIG. 2b) from sensors A-O. Each time the carriage carrying the optical character detection unit 1 moves by a certain amount by the operation of the lateral movement circuit 17, the movement circuit 17 generates a sampling pulse (upper part of FIG. 2c). is simultaneously sent to digitizing memory 14 and optical detection circuit 18. Since the memory 14 has previously stored the print pattern code of the character D (FIG. 2c), this print pattern code is sequentially sampled by the sampling pulse from the moving circuit 17 and sent to the coincidence judgment circuit 15. The optical detection circuit 18 also samples the scanning signals from the sensors A to O using the sampling pulse from the moving circuit 17, digitizes it, and sends it to the coincidence determination circuit 15. In the match judgment circuit 15,
The output signals of both the memory 14 and the detection circuit 18 are sequentially compared, and as long as they match, the logic 1 output is sent to the AND circuit 9 as in the normal case. An output of 0 is sent to AND circuit 9 to close the inputs of print wheel drive and hammer operation circuit 10 to stop the next printing operation and to generate an alarm signal in any suitable manner. It goes without saying that the half-level storage locations indicated by the hatched areas in FIG. 2c are to be removed from the comparison.

Thus, the premise of this invention is to ensure that printing errors are completely checked by immediately mechanically reading the newly printed characters using a character reader and directly comparing the result with the print input signal. A new printer method has been revealed.

FIG. 5 is a block diagram showing one embodiment of the present invention. Most of the circuits are the same as those shown in FIG. 4, but the difference is that a print memory 20, a back direction instruction circuit 21, and an error judgment circuit 19 are added.

The operation of this circuit is as follows, and the same parts as in FIG. 4 will be briefly described.

First, it is assumed that the print command generation section 16 issues a print command for the letter D in response to an external command. This command signal is then delayed by the period of one print cycle required for the printer to print one character (the delay circuit is not shown) and is stored in the print memory 20. At the same time, the above print command signal is also delayed by one print cycle (the delay circuit is not shown) and sent to the print pattern decoder 13.
to go into. Then, the decoder 13 outputs a digital signal in response to the digitization memory 1.
4 stores digital information of the letter D as shown in FIG. 2c.

On the other hand, the print command signal issued from the print command generation section 16 enters the lateral movement circuit 17, which moves the printer's carriage 38 sideways by one character to prepare a new printing position, and also moves the printer's carriage 38 sideways by one character, and prepares a new printing position, and also moves the printer's carriage 38 sideways by one character. A command is sent to the movement amount instruction circuit 8, and the circuit 8
determines the amount by which the type wheel 4 should be rotated from the reference position in order to print the letter D, and sends this rotation amount signal to the print wheel drive and hammer operation circuit 10 via the AND circuit 9. This circuit 10 operates the hammer after rotating the type wheel 4 by a predetermined amount according to the received rotation amount signal.
The required character D is printed on the surface of the printing paper 12.

Next, when the print command unit 16 issues the next print command in response to a second external command, this command signal is transmitted to the lateral movement circuit 17 as before, and this circuit 1
Step 7 moves the carriage 38 of the printer in the horizontal direction by one character, but since the optical detection unit 1 is integrally attached to this carriage 38, the optical sensor A to O in the detection unit 1 is printed just now. The character D that has just been written will be scanned. The optical detection circuit 18 thus detects the letter D scanning signal (FIG. 2b) from sensors A-O. On the other hand, when the lateral movement circuit 17 moves the optical character detection section 1 in the lateral direction to scan the printed character D,
Sampling pulses are generated at appropriate intervals, and the sampling pulses are simultaneously sent to the optical detection circuit 18 and the digitizing memory 14. Thus, since the print pattern code of the character D (FIG. 2c) has been previously stored in the memory 14, this print pattern code is sequentially sampled using the aforementioned sampling pulse and sent to the coincidence judgment circuit 15. On the other hand, the optical detection circuit 18
Also, the scanning signals from sensors A to O are sampled using sampling pulses, digitized, and sent to the coincidence judgment circuit 15. Match judgment circuit 15
There is no problem if the two signals match, but if they do not match, the AND circuit 9 is closed and the next printing operation is stopped (up to this point the explanation is the same as in FIG. 4).
Further, the coincidence judgment circuit 15 operates the back direction instruction circuit 21 and sends a signal to the lateral movement circuit 17 to return the carriage 38 by one character. The coincidence judgment circuit 15 also sends a signal to the print memory 20 to operate it, calls up the already printed character D stored in the memory 20, sends a print signal through the print command generation section 16, and sends a print signal to the carriage 38.
The printing hammer in printed the letter D first,
The same letter D is printed over the same position.

In this way, in the past, humans visually checked whether the printed characters were clear or unclear, and if the characters were pale or unclear, they had to be manually reprinted, but this invention eliminates this hassle. did.

Further, according to the present invention, not only the printed characters are read by the character reading means, but also a character pattern digital signal is generated from the signal read and digitized by the character reading means and the signal of the character to be printed. Since the sharpness of the print is determined by comparing the signal outputted by the decoding means that outputs the , the sharpness can be determined extremely accurately.

As explained above, this invention can be applied in various ways and has excellent practical effects.

[Brief explanation of the drawing]

FIG. 1a is a top view of the platen and carriage in the printer, and FIG. 1b is a front view of the paper guide. FIG. 2 is a diagram showing the character reading operation of the optical character detection section, the read output, and the digitized information thereof. Fig. 3 is a diagram showing a printing check system in a conventional printer, Fig. 4 is a block diagram showing a printing error check system which is the premise of this invention, and Fig. 5 is a block diagram showing an embodiment of this invention. be. In the figure, 30 is a platen, 31 is a printing paper, 32 is a paper guide, 33 is an opening, 34 is an ink ribbon, 4 is a type wheel, 36 is a hammer, 37 is a type selection motor, 38 is a carriage,
39 is a shaft, 1 is an optical character detection unit, A to O are optical sensors, 7 is a print command generation unit, 2 is a type wheel movement amount instruction circuit, 3 is a print wheel drive and printing circuit, 4 is a type wheel , 5 is a wheel clock counter, 6 is a coincidence judgment circuit,
16 is a print command generation unit, 17 is a lateral movement circuit,
8 is a printing wheel movement amount indicating circuit, 9 is an AND circuit, 10 is a printing wheel driving and hammer operation circuit, 12 is a printing paper, 13 is a printing pattern decoder, 14 is a digitizing memory, 15 is a coincidence judgment circuit, and 18 is a 20 is a print memory, 21 is a back direction indicating circuit, and 19 is an error determining circuit.

Claims (1)

[Claims] 1. A printing means, a carriage for placing the printing means, a lateral movement means for moving the carriage in the lateral direction, and a plurality of cartridges attached to the carriage so as to move together with the printing means. a character reading means having a structure in which optical sensors are vertically arranged; a decoding means for receiving a signal of a character to be printed and outputting a character pattern digital signal; and a digitized output of the character reading means. Comparison means for comparing the character pattern digital signal outputted by the decoding means, and after printing by the printing means, when the printing means moves in the horizontal direction, the character reading means reads the printed characters and the result is read by the character reading means. The output signal of the decoding means is compared with the output signal of the decoding means in the comparison means, and when a discrepancy is detected, the carriage is returned by the lateral movement means to print the same printed character again at the same printing position. A serial printer characterized by: