JPH03120061A - Serial printer - Google Patents

Abstract

PURPOSE:To allow using a printer with the quality of print kept even when a failure of dot printing occurs, by a method wherein, in the case when one of groups of print elements is used, the moving speed of a print head is reduced below the normal speed and the print element driving frequency is reduced. CONSTITUTION:A designating device, by which a user designates one of two groups of print elements when the user finds out a trouble in a printer, and a control device which controls transfer of print data to a print element driving circuit 41 or 42 according to the designation are provided. Thereby, the printing method can be temporarily changed over to the nearly same one as a conventional single-row head printer even when one of the two groups of print elements gets into trouble, so that the user is allowed to continues to use the printer without dot omission and with maintaining the printing quality by utilizing the group of print elements which is not in trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a serial dot matrix printer (hereinafter referred to as a two-row head printer) equipped with a print head in which a group of printing elements are arranged in parallel.

[Conventional technology]

A two-row head printer has a printing method that doubles the printing speed while using printing elements with the same performance by arranging two groups of printing elements in parallel and sharing dot printing between each printing element group. This is the printer used. Although this method can improve the printing speed, it also doubles the number of printing elements, which increases the number of mechanical parts inside the print head and electronic parts of the print element drive circuit. This will increase the failure rate of surrounding areas. As a result, the period until dot printing defects begin to occur tends to be shortened.

In conventional two-row head printers, when even one such failure occurs, the printer has no choice but to stop using the printer or continue to use it with the missing dot until the failed part is repaired or parts replaced.

[Problem to be solved by the invention]

The present invention has been devised in view of the above-mentioned problems, and provides a two-row head printer that can be used continuously while maintaining printing quality even if a dot printing defect occurs, if the failure is minor. The purpose is to

[Means to solve the problem]

In order to solve the above problems, the present invention provides a means for specifying which printing element of two printing element groups to use when a printer user discovers a failure, and a means for specifying which printing element to use from two printing element groups. Accordingly, means for controlling the transfer of print data to the print element drive circuit is provided.

[Effect]

By providing the above means, even if one of the two printing element groups fails, it is possible to pseudo-switch to the same printing method as the conventional single-row head printer.
It is possible to continue using the printer with print quality without missing dots by making use of the print element on the non-faulty side.

〔Example〕

(Example 1) Embodiments of the present invention will be described based on the drawings.

FIG. 1 is a view of a two-row print head, which has two rows of wire tips 103 and two rows of printing element groups 101 and 102, seen from the printing surface side, which is used in this embodiment.

Two printing element groups each having eight printing elements are arranged with an interval L between them. The distance NL is an integral multiple of the dot density in the horizontal direction of the printer, and the unit is "dot." Each printing element uses an impact method in which a wire is driven by an electromagnet and dots are printed on the medium via an ink ribbon or the like. . The name of each printing element group is such that the left side of FIG. 1 is "right" when viewed from the back of the print head toward the medium.

FIG. 2 is a diagram showing the configuration of this embodiment, in which 1 is a microprocessor (hereinafter referred to as MPU), 2 is an image buffer storing a print image, and 31 and 32 are print data gate means for the left print element, respectively. The printing data gate means 41 and 42 of the right printing element are respectively a left printing element driving circuit and a right printing element driving circuit 51 and 5.
2 is a left printing element group and a right printing element group each containing eight coils; 6 is a carriage motor that reciprocates the print head in the printing direction; 7 is a carriage motor drive circuit; and 8 is an operator who specifies the printing element group to be used. From the MPUI to the print data gate means 31.32, the signals 5ELL01.5EL102.5EL1 are sent to the panel, respectively.
03, 5EL201.5EL202.5EL203 are input, and a print element drive timing signal is supplied from the MPUI to the print element drive circuits 41 and 42. Also,
MPU 1 controls carriage motor drive circuit 7 .

Furthermore, the MPU 1 receives output from the operator panel 8.

FIG. 3 shows an example of the circuit of the print data gate means 31 and 32.
Eight of these circuits are arranged in each dot 31 and 32, and control the data flow of each dot.

11.13 in the same figure is a selector that selects 1 data from 2 data, and when input S is "1'', data of A is selected.
Output.

First, the operation of the circuit shown in FIG. 3 will be explained with reference to the waveform diagram shown in FIG. 4. 5ELIOI・5ELL02・5ELI
03 are all set to "1", one dot worth of print data is written into the D flip-flop 9 at the rising edge of the write signal WR. The output Q1 of the D flip-flop 9 is the output of the T flip-flop 10.
It is manually operated as a toggle trigger. One of the outputs Q2 and -Q2 of the T flip-flop 10 is selected by the selector 11 and input to the AND gate 12. On the other hand, Ql is manually input to the other input of the AND gate 12. That is, the output Y of the AND gate 12 is
As shown in the figure, every other "1" part of the output Q1 of the D flip-flop 9 is replaced with a "0" part.The selection of whether to replace the even numbered part or the odd numbered part is made by the signal 5ELIOI. The AND gate 12
The selector 13 further controlled by the signal 5EL102 selects one of the outputs and Ql. Finally, the signal 5ELL 03 controls whether the output of the selector 13 passes through the AND gate 14 or is blocked.

By combining the signals 5EL101, 5EL102, and 5EL103, the final output of this circuit is: - Only the odd numbers out of the "'1" of the human input data have passed. - Only the even numbers out of the input data 1111+. It is clear from the circuit diagram that the four values ``°0'' are selected regardless of the input data.

41 like this! In the constructed circuits of FIGS. 2 and 3, if the operator panel 8 specifies that both the left and right printing element groups are to be used, the MPU selects the print data selection means from the above-mentioned 5EL101/5EL102/5 so that the print data selection means becomes ■
ELI 03/5EL201/5EL202/5EL2
Set 03.

Then, before giving one print timing pulse to the print element group drive circuit 41.42, pattern data is read out from the image buffer 2 by 1 byte on the left side and 1 byte on the left side, and sent to the print data gate means 31.32. At this time, the read address from the image data 2 is determined according to the distance between the left and right printing element groups and the L dot1.For example, when the print head moves from left to right, the left printing element For the printing element group on the right side,
Since the same position is reached with a delay of the time corresponding to the printing of the L dot, it is sufficient to delay the progress of the read address from the image buffer 2 as much as possible.

Print data game 1/means 31.32 is set above ■
- The data passed according to the condition (■) is input to the printing element drive circuits 41 and 42. Print element drive circuit 41.42
is the printing element group 5 in synchronization with the timing signal from the MPU.
Drive 1.52.

At the same time as this data transfer/output operation is repeated at a cycle F, the MPU instructs the carriage drive circuit 7 to drive the carriage motor 6 at a speed S, so that one line of printing becomes (j
It becomes popular.

Due to the operation of the print data gate means 31 and 32, the fifth
As shown in the figure, pattern data (a
) is divided into (b) and (c). In other words, in (b), the first and third dots from the left in each row of the matrix in (a) are valid.
), in (C), the second and fourth dots are enabled (i.e., the front is closed), and these (b) and (C) are printed by the left and right printing elements nr, respectively. do.

Here, the original pattern (a) is a so-called half-dot pattern that prohibits the definition of adjacent dots in the horizontal direction, and in a printer that prints this as it is with a single row of heads, it is twice the maximum response frequency of each printing element. You can print with
In (b) and (C), there is a pattern in which one or more dots are not defined every four timings, and the printing element drive timing frequency F can be set to four times the maximum response frequency of each printing element. The moving speed S of the carriage is a value determined so that the dot printing density at this frequency F becomes a predetermined density. The steps up to this point correspond to normal operation as a two-row head printer.

Next, due to a paper jam, one or more wires in the left printing element group were broken, causing missing dots in the above normal printing mode, so only the right printing element group was used. The following explanation assumes that the operator panel 8 specifies the following.

At this time, the MPU controls the 5EL101 and 5E so that the print data gate means 31 enters the above-mentioned state (2), that is, input data is blocked, and the print data selection means 32 enters (2), that is, the state that allows input data to pass through.
LL 02/5ELI03/5EL201/5EL20
2.5 Set EL203.

Then, as in the case of using the left and right printing element groups described above, one printing timing pulse is applied to the printing element drive circuit 41.
．． 42, the pattern data is read out from the image buffer 2 by 1 byte on the left corner and 1 byte on the right side, and written to the print data gate means 31 and 32. There is no need to transfer it here because it is all blocked in , but in order to avoid complicating the control sequence and as necessary in the second embodiment described later, the same operation as in the above case is used.

The data that has passed through the print data gate means 32 according to the condition (2) is inputted to the print element drive circuit 42. The printing element group driving circuit 42 drives the right printing element group 52 in synchronization with the timing signal from the MPU.

It is clear that this data transfer/printing operation must be repeated at a cycle less than half of the cycle F in the above case in which left and right printing element groups were used, that is, the cycle F is Although this was achieved by driving the left and right printing elements alternately, in this case, the pattern data was shared to achieve this, and (a) in Figure 5 was printed as is. Because there is.

Similarly, the MPU instructs the carriage drive circuit 7 to drive the carriage motor 6 at a speed of S/2 or less.

In this way, even if the left printing element group fails, printing without missing dots can be performed using only the right printing element group.

Although we will not discuss in detail the case in which the right printing element group fails, it is clear that if the settings of the printing data gate means 103 and 203 are reversed to those in case 2, the rest is the same.

(Example 2) In Example 1, the printing elements were selected in units of printing element groups, but in Fig. 2, the designation from the operator panel 8 is to independently select left and right use and left use for each of the eight dot positions.・Enable to specify right use, and further increase MP
5ELI01, 5EL102, 5EL103 from U1
・5EL201・5EL202・5EL203 signal is 8
If the number of dots is prepared (Fig. 6), even if the failure location is scattered among the left and right printing element groups, if one of the two printing elements with the same vertical dot position is usable, then one can be used. There is no need to explain that printing is possible in the same way as in the example above.For example, in the print head diagram in Figure 1, the top three "left" bins and the bottom three
When the "right" bin of a book breaks, the print data gate means 31 for the top three bins is set to ■ and 32 is set to ■, and for the bottom three bins, 31 is set to ■ and 32 is set to For the two central lines, if 31 is set to ■ and 32 is set to ■, printing can be performed at a printing speed of S/2 in the same way as printing only on the left side or only on the right side in the first embodiment. The dot patterns printed at this time are distributed as shown in FIG. (b) for the pattern data on the image buffer (a)
The left printing element group is responsible for (c), and the right printing element group is responsible for (c).

〔Effect of the invention〕

As described above, according to the present invention, when a certain printing element becomes defective in a two-row head printer, the printing element located at the same vertical position as the defective printing element in the other printing element group operates. If possible, you can switch to a mode that uses only operational print elements to continue printing. Therefore, after a printer user discovers a malfunction in the print head such as a broken bottle or a clogged nozzle, he/she requests replacement parts from the manufacturer/seller and waits until the parts are delivered to the user. There is a high possibility that the worst inconvenience of having to live with the print results or giving up on using the printer can be eliminated.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the arrangement of printing elements as viewed from the printing surface side of an example of a two-row head to which the present invention is directed. FIG. 2 is a configuration diagram of the first embodiment of the present invention. FIG. 3 is a diagram showing an example of the circuit of the print data gate means. FIG. 4 is a voltage waveform chart of the print data gate means. FIGS. 5(a), 5(b), and 5(c) are diagrams showing examples of pattern sharing when left and right printing element groups are used. FIG. 6 is a configuration diagram of a second embodiment of the present invention. FIGS. 7(a), 7(b), and 7(c) are diagrams showing examples of pattern assignment in the second embodiment. that's all

Claims (3)

[Claims] (1) A serial printer having a print head in which two sets of print element groups are arranged in parallel, and whether only the first print element group or only the second print element group is used during printing; a printing mode specifying means for selecting and specifying whether to use both of the two sets, and one for each printing element, and according to the specification of the printing mode specifying means, passing, blocking, or one printing data bit. a print data gate means for controlling the passage of the print head; a carriage control means for reducing the print head movement speed than normal when only one of the print element groups is used in the above case; , printing element control means for lowering the printing element drive frequency than normal when only one printing element group is used. (2) The serial printer according to claim 1, wherein the printing mode specification means specifies one printing element group as a unit. (3) The serial printer according to claim 1, wherein the printing mode specification means specifies one printing element at a time.