JPS61123545A - Printer - Google Patents

Abstract

PURPOSE:To obtain a dot matrix type printer which can prevent a loss time from to be generated by carrying out a printing of an inferior channel with a regular channel when a lack of dot is occured in some channel. CONSTITUTION:A normal printing is carried out when a carriage is displaced in the right direction, and a substitute printing is carried out when a channel miss is occured and the carriage is displaced in the left direction. To that end, a printing part of an inferior channel is substituted by the regular channel, after a blank is displaced by integral number times of a dot distance in a longitudinal direction relative to a print head, and the situation that the printer becomes in an unusable state till the service man arrives there is disolved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a dot matrix type printer.

(Prior Art) Dot matrix printers (wire dot printers, inkjet printers, thermal printers, thermal transfer printers, etc.) perform printing operations by forming characters and figures using a large number of dots.

For this reason, this type of printer usually has a plurality of dot forming mechanisms in one head.

However, the reliability of these dot forming mechanisms is not necessarily perfect. For example, in thermal printers and thermal transfer printers, the dot forming mechanism (heating element) is damaged due to deterioration over time, and in inkjet printers, the operation of the dot forming mechanism (ink ejection) may be affected due to dirt, air bubbles, or drying of the ink. It won't work properly'1
Further, in wire dot printers, the dot forming mechanism deteriorates over time due to damage or wear of the wire, and does not function properly.

(Problems to be Solved by the Invention) Conventionally, when such a trouble occurred, the print head was replaced with a new one, and the removed print head was discarded as a defective product.

For this reason, it was uneconomical. In addition, a service person had to come and replace the print head, which meant a lot of lost time for the user.

In the case of inkjet printers, even if dots are missing, they are usually equipped with a recovery mechanism, so this may recover the dots, but the recovery effect is not always sufficient. Due to the current situation, the above problem could not be avoided.

The present invention has been made in view of the above-mentioned problems, and its purpose is: (1) To eliminate the situation (loss time) in which the printer becomes unusable until a service person comes when a failure such as a missing dot occurs.

■When you don't want the printer to stop (such as when using it continuously), you can deal with missing dots by any chance.
To realize a printer capable of continuing perfectly normal recording in other respects, although the recording speed is reduced. That is, to realize a printer in which the print head can be replaced only after the operating rate of the printer has decreased.

■For users whose operating rate is not very high, even if a small number of channels have missing dots, they can continue normal printing without replacing the print head, and if the missing dots spread to a large number of channels, they can continue normal printing. To realize a highly economical printer that only needs to be replaced.

etc.

(Means for Solving Problems) The present invention, which solves problem E, is configured such that when a dot is missing in a certain channel in a dot matrix printer, printing of the defective channel is also performed using other normal channels. It is characterized by the fact that

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

This embodiment is a drop-on-demand type inkjet printer, and in the figure, numeral 1 is a recording paper on a platen, and recording is performed by ink droplets ejected from a print head 2. The print head 2 has a plurality of nozzles (channels) and is mounted on a carriage 3. Kii? The spool 3 is attached to a transfer belt 5, and the transfer belt 5 is wound between a drive pulley 6 attached to the output shaft of a pulse motor 4 and a tension pulley 7. This configuration allows the print head 2 to move within the AA' section.

Note that the BB' section within the AA' section is the section where the print head 2 runs opposite the recording paper 1, and the section @C is the section where the print head 2 sequentially ejects ink droplets from all channels to prevent clogging, etc. The spit position 11D, which detects missing dots (hereinafter referred to as channel mistakes), is the purge position where ink is forcibly discharged when there is a channel mistake.

Above, near the spit position C, there is a channel miss detector 8 that detects whether or not ink droplets are flying accurately.
and a position detector 9 for detecting that the print head 2 is at the spit position C are installed. Further, an ink reservoir 10 for receiving ink discharged from each nozzle and a position detector 11 for detecting that the print head 2 is at the purge position are installed near the purge position. Note that the channel miss detector 8 may be of any type, such as a rechargeable type or a charge measuring type. Further, the position detectors 9 and 11 are microswitches and charging detectors.

A magnetic detector or the like is used. Reference numeral 12 denotes a control unit that performs various controls, and this control unit 12 receives output signals from the channel miss detector 8, output signals from the position detectors 9 and 11, etc.
A control signal based on a predetermined sequence is sent to the motor drive unit 13.
The data is output to the head drive section 14, etc. Reference numeral 15 denotes a motor drive unit for feeding the recording paper, which drives a pulse motor (not shown) based on the output of the control unit 12. Further, 16 is a display unit that indicates that the print head 2 in which the channel error has occurred is in a recording mode (in this specification m*, this is called support mode), 16a is an indicator lamp, and 16b is a normal display unit. Recording mode (in Honkawa lIm,
This is called the normal mode and is a switch for forcibly transitioning from the normal mode (which is done when the head moves from left to right in the figure) to the support mode.

Next, the print head 2 used in this embodiment will be explained with reference to FIGS. 2 and 3. Inside the print head 2, there are a plurality of pressure chambers 21, nozzles 22, and supply passages 23.
, a common ink storage chamber 24 and an introduction passage 25 are formed. These pressure chambers 21 are formed in double rows in the direction of movement of the print head 2, and the number thereof is determined based on the relationship between stroke formation, and this figure shows an example of seven chambers. 26 is pressure! A coverslip 21 forms a side wall, and a piezoelectric transducer 27 (the same number as the pressure seedlings 21) is disposed on the coverslip 26, and these three constitute seven sets of flexible wall sections. Reference numeral 29 denotes an elastic plate constituting the upper lid of the ink storage chamber 24, and is configured in advance so that it can expand or contract depending on the amount of blank ink.

Reference numeral 30 denotes ink detection means provided on the upper surface of the elastic plate 29, which outputs a signal indicating the amount of ink in the ink storage chamber 24 to the control section 12. Reference numeral 31 denotes a balloon container for replenishing ink made of an elastic material, and the inside is heated to a predetermined pressure (for example, 0.6 to
0.1 kg/am2). 32 is a communication pipe that connects the introduction passage 25 with the balloon container 1131, and 33 is an automatic pulp provided in the middle of the communication pipe 32. Reference numeral 34 denotes a pulp operating means, which is controlled based on the output of the ink layer detection means 3o and outputs a signal for closing the automatic pulp 33 (1). Reference numeral 35 denotes a forced operating means for forcibly opening the automatic pulp 33 (configured within the head drive unit 14). This coercive means 35
The automatic pulp 33 is opened by the output signal of the 1ilIt11 section 12, and by the contraction of the balloon container 31, ink can be ejected from all nozzles 32 to the outside. The ink path up to the nozzle 22 can be purged.

Next, the operation of the ink jet printer having the above configuration will be explained with reference to FIG. Incidentally, during the printing operation, the action of ejecting ink droplets from the nozzle 22 and the action of replenishing ink from the ink storage v24 to each pressure chamber 21,
Since the automatic feeding of ink into the ink reservoir 1924 is the same as that of conventionally known inkjet printers,
The explanation thereof will be omitted here.

The inkjet printer according to the present invention performs a printing operation by moving the print head 2 in the sub-scanning direction under the control of the control unit 12. At this time, the control unit 12 moves the print head 2 to the spit position C at fixed time m<for example, 90 seconds).
move it to Since the print head 2 is stopped based on the detection signal from the position detector 9, the print head 2 is reliably stopped at position WIC. Next, the control unit 12 starts the spitting operation. That is, as shown in FIG. 4, a pulse signal S11. S12°S13.・
..., 5IN (N is the number of nozzles, in this example, 7
) is output from the head drive section 14 to the print head 2. When the ink droplets ejected from each nozzle penetrate after a certain period of time T2 and fly and collide with the channel miss detector 8, the channel miss detector 8 outputs a signal S20 shown in FIG. 4 to the control unit 12. . The control unit 12 generates drive pulses S11. S12. . . . monitors whether or not a pulse responding to S1N is present in the signal 820, and if there is no pulse missing, returns the print head 2 to the printing section and continues normal recording operation, while outputting a responding pulse. If even one is missing, it is determined that a channel error has occurred, and the print head 2 is moved to the purge position ff1D, the forced operation means 35 is activated, and the ink flow paths in the print head 2 are cleared all at once. Purge. This usually eliminates clogging and the like. After the purging operation is completed, the control unit 12 performs the spitting operation again and confirms that clogging and the like have been eliminated. After confirming that clogging and the like have been removed, the print head 2 is returned to the printing section BB' and the printing operation is performed again.

If the channel error is not resolved even after performing the above purge operation, the control unit 12 repeats the above purge operation, for example, three times. If this does not solve the problem of missing dots, a more powerful purge method (driving the print head 2 with high frequency) is applied if necessary, and if it still does not solve the problem, the system shifts to support mode. After transitioning to this support mode, the control unit 12 turns on the display lamp 16a (a buzzer or the like may also be used) and performs the recording operation as described below. In the following explanation, the print head 2 has seven vertical channels (Ch 1, Ch 2, ..., Ch 7 from the top, with the Chl side being the downstream side in the paper feeding direction), that is, the number of channels is Explanation will be given by taking seven print heads 2 as an example. In this support mode, when the carriage 3 is moved to the right in Fig. 1, a print signal is not sent to the channel where the channel error has occurred (here Ch5), and the normal channel (Oh5) is sent. Printing is performed by sending a print signal only to channels other than those in the other channels (first printing operation). Then, when moving the carriage 3 to the left in Fig. 1, first send the recording -1 upward in Fig. 1 by one dot (the nozzle interval), and then, while moving the carriage 3, The printing portion of channel Ch5 is printed on behalf of the adjacent normal channel Ch4. That is, the print signal that should be applied to channel Ch5 when the carriage 3 moves to the right is read out and applied to channel Ch4 when the carriage 3 moves to the left, thereby performing proxy printing (second printing operation). ). With the above-mentioned first and second printing operations, the printing of the - character is completed, so line feeding is performed after this printing operation. However, the line spacing in this case is one dot less than the normal line spacing.

By the way, if a channel error occurs in channel Ch1, the paper must be fed by one dot in the opposite direction (downward in Figure 1) before starting the second printing vJ process, and the paper Due to the structure of the feeding mechanism, paper feeding accuracy decreases and printing quality also deteriorates. Therefore, regarding the channel error in channel Ch 1, the paper is fed one dot less than the original paper feed amount during line feed, and the second printing operation is performed on channel Oh 2 more than the first printing operation. After performing this first, the paper is fed by one dot, and the first printing operation is performed thereafter. In this case, the reading of the print signal is the reverse of the above case.

FIG. 5 is a flowchart showing the above operation. According to such printing, a print signal is not sent to a channel where a channel error has occurred, and quality deterioration such as staining does not occur even when a channel error is determined due to ink scattering. Further, although the overall printing speed is reduced by approximately half, the effect of being able to perform complete printing even in abnormal situations is significant.

The print head 2 is inspected for channel errors at predetermined intervals as described above. Therefore, the control unit 12 can know that the channel error has been resolved for some reason. When the control unit 12 learns of this channel error,
Return from support mode to normal mode. Also, defects that cannot be detected by the channel error detector 8 (for example, a situation where the dot position is significantly deviated from the normal position)
If this occurs, the switch 16b can be used to forcibly shift to the support mode. In this case, the defective channel number is input by operating keys on an operation panel (not shown) (in this case, there is no automatic return to normal mode).

Although it is rare for a channel error to occur in multiple channels, even in such a case, substitute printing can be performed if a similar algorithm is determined in advance. In this case, it is preferable to decide which signal is applied to which normal channel so that printing can be performed on the normal channel at the fastest speed.

For example, if a channel error occurs in two channels, proxy printing may be performed using an algorithm as shown in FIG. This algorithm determines whether the two channel misses occur on adjacent channels or not.Channel Ch1. Whether at least one of Ch 2 is a channel miss, whether channel Ch1 is a channel miss, whether channel Ch7 is a channel miss,
The order of printing and paper feeding is determined based on the following four judgments.

Next, printing in the support mode will be explained in more detail using FIGS. 7 and 8. In FIG. 7, reference numeral 40 denotes a recording control unit which obtains a character pattern signal to be printed from a character pattern memory 42 based on print information given from an external device 41 such as a computer, and transmits this to each channel Ch1.
It is applied to one input terminal of the AND gates 43+ to 437 corresponding to ~Ch 7. 44 is a pattern memory, in the support mode, for example, the above-mentioned first and second patterns are stored.
This is for temporarily storing pattern signals used in the second printing operation when performing the second printing operation. 4
Reference numeral 5 denotes a clock generating section that generates clock pulses for controlling print timing, and the clock pulses from this generating section are inputted to the other input terminals of gates 431 to 437 and to the recording control section 40. Also, 461-467 are gates 431-
Amplify the output of 437 and use drive crystal 47r~4
This is an amplifier that feeds the 77. In comparison with the apparatus of FIG. 1, the recording control section 40. The memory 42° 44 and the clock generator 45 are included in the control unit 12, and the gate 43
1 to 437 and amplifiers 461 to 467 are head drive unit 1
4, and also Drive Crystal 47+~477
corresponds to the piezoelectric transducer 27.

In the circuit shown in FIG. 7, in the normal mode, character pattern signals read from the character pattern memory 42 are sent to the corresponding gates 431 to 437 in synchronization with clock pulses output from the clock generator 45. Printing is performed. Now, as shown in Figure 8 (a), 5 (horizontal)
The letter A formed by X7 (!1ffl) dots (
For example, when printing a black dot (the circle mark part is a black dot), in synchronization with the clock pulse, gates 431 to 437 are printed with ■,
■.

Character pattern signals are sent in the order of ■, (su, ■) and printing is performed (in the case of right-handed printing).
If a missing dot occurs in h5, the recording control section 40 stores the pattern data for channel Ch5 in the pattern memory 44, and prints on channels other than channel Ch5 by right-handed printing. After the paper has been fed by one dot, the pattern signal that should originally be given to channel Ch5 is given to channel Ch5 in the opposite direction to perform left-handed printing. That is, taking printing A as an example, the first printing operation prints a pattern in which the defective channel Ch5 shown in FIG. The pattern shown in FIG. 8(c) is printed using only the normal channel Ch4, and with the above two printing operations,
Printing of the character pattern shown in FIG. 8(a) is completed. The same applies when there is a channel error in another channel. However, as mentioned above, there are some differences in the algorithm depending on the channel. In addition, the capacity of the pattern memory 44 is selected to be large, and the printing pattern of the corresponding line (corresponding to FIG. The second printing operation may also be performed by reading data from the memory 44.

Incidentally, in the above embodiment, when a defective channel occurs, all normal channels except the defective channel are used, but printing may be continued using a continuous group of normal channels. . For example, if a missing dot occurs in the channel group 115, a series of normal channel groups C111, Ch2. Ch 3 and Ch
4 to print a 5x4 character dot pattern, or a series of normal channel groups Ch6 and Ch.
7 may be used to perform one printing operation of a 5×2 character dot pattern. Of course, in this case, if the pattern read from the character pattern memory 42 is divided into patterns that match the channel groups of the series of normal channel groups, that is, if the read pattern is 5×7, the ejection pattern is also divided. It will be used in a 5x7 configuration. When using this series of normal channel groups, due to the relationship with printing speed, a normal channel group with a large number of channels (in the above example, channels Ch1 to C
It is preferable to use a channel group consisting of h4).

In this embodiment, the normal mode is printed to the right and the support mode is printed to the left. However, the normal mode may be printed to the left and the support mode is printed to the right, or both normal mode and support mode may be printed in the same direction. Of course, it is possible. Also, depending on the purpose of the printer,
For example, in an EDP printer, it may be acceptable even if all channels are not completely aligned. In such applications, the support mode may not be entered until there is one channel error, and printing may continue in the normal mode with one missing dot. Furthermore, it may be possible to allow even two discontinuous dots to be missing. It is preferable to provide a switch inside the printer so that the operator can select these.

Further, although the above description was given in the case where the present invention is applied to an inkjet printer, the present invention is not limited to this and can be applied to other dot matrix type printers.

(Effects of the Invention) As explained above, according to the present invention, it is possible to realize a printer that can continue operation even if a channel error occurs, and therefore does not cause loss time as in the conventional printer and does not necessarily require replacing the print head. .

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
Figure 3 is a detailed explanatory diagram of the print head portion of the device; Figure 3 is an , FIG. 8 is an explanatory diagram of the operation of the circuit of FIG. 7. 1... Recording paper 2... Print head 3.
...Carriage 4...Pulse motor 5...Transfer belt 8...Channel miss detector 9.11...Position detector 1o...Ink reservoir 12...Control unit 13.15
...Motor drive section 14...Head drive section 16...Support mode display section 22...Nozzle 27...Piezoelectric conversion element 31
...Balloon container 33...Automatic valve 34...
Valve operation means 35... Forced operation means 40... Recording control section 41.
...External device 42.44...Memory 45...
Clock generator patent applicant Roku Konishi Photo Industry Co., Ltd. Representative Patent attorney Fuji Ijima 1 person'FIP, 1 diagram, 3 figures, pIA 4 figure, Figure 5

Claims (9)

[Claims] (1) A printer of a dot matrix type, characterized in that, when a missing dot occurs in a channel, printing on the defective channel is also performed using other normal channels. (2) The printer according to claim 1, wherein the printer is configured so that printing of the defective channel is performed by a specific normal channel. (3) When the carriage moves to the right, normal printing is performed, and when the carriage moves to the left, the printing paper and print head are moved by an integral multiple of the vertical dot interval for substitute printing. 3. The printer according to claim 2, wherein after the printer moves relatively, the printing performed by the defective channel is replaced by the normal channel. (4) During line feeding, first, for substitute printing, the recording paper and print head are moved relative to each other by an integer multiple of the vertical dot spacing than the normal line feeding, and the print head is moved relative to the print head by an integral multiple of the vertical dot spacing to compensate for the printing in the defective channel. After performing this on the normal channel, the recording paper and the print head are moved relative to each other by the integer multiple to complete line feeding and perform normal printing. printer. (5) The first aspect of the present invention is characterized in that it is provided with a notification means for indicating when a support mode is entered in which the part printed on the defective channel is printed on the normal channel.
The printer according to any one of items 1 to 4. (6) The printer according to any one of claims 1 to 5, further comprising a detector for detecting missing dots. (7) The printer according to claim 1, wherein when a dot drop occurs in a certain channel, printing is continued using a continuous group of normal channels. (8) The printer according to claim 7, wherein a normal channel group having a large number of channels is used as the series of normal channel groups. (9) The printer according to any one of claims 1 to 8, characterized in that the printer is configured to enter a support mode when the number of missing dots exceeds a certain number.