JPH0671947A - Ink jet printer - Google Patents

Abstract

PURPOSE:To print at high speed and density by using a line type ink jet printer having comparatively low density. CONSTITUTION:In an ink jet head 12, ink jet nozzles 13 are arranged in the direction of line at comparatively low density and at a dot pitch P with regular intervals. The head 12 is carried by a carriage 16. The carriage 16 can be driven to be sent at a divided pitch p obtained by further dividing the dot pitch P by an eccentric feed cam 18. On the other hand, a paper 11 is sent or returned for a predetermined quantity by a feed roller 29 or a return roller 20, and high density printing is performed by moving the paper 11 at each dot position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer, and more particularly to an improvement of a head feed and paper feed control mechanism for enabling high density dot printing by using an ink jet head in which ink jet nozzles are arranged at a low density.

[0002]

2. Description of the Related Art Printers that output desired characters, symbols, numbers, etc. on paper are widely used as output devices such as computers or word processors.
In recent years, such printers have also been used as label printers for various barcodes, block codes and the like.

In recent years, dot printers capable of printing all character fonts with arbitrary dot combinations have become mainstream. Further, among these dot printers, ink jet printers are noiseless and dot superposition is easy. Has many advantages.

However, in such an ink jet printer, since the structure of the ink jet head is relatively precise, it is difficult to arrange a large number of ink jet nozzles at a high density. Most type printers. According to this serial ink jet printer, an ink jet head having a single ink jet nozzle or a plurality of nozzles arranged in a column direction is used. Has been obtained.

[0005]

However, in such a serial type ink jet printer, there is a problem that the high speed and high density printing cannot be performed due to the limitation of the entire printing speed. In order to perform such high-speed and high-density printing, a head that can print multiple dots at a time in the row direction, which is conventionally known as a line printer, is provided, and high-speed printing is performed by alternately repeating one-line printing and paper feeding. Is preferably performed. However, in order to realize such a line type printer with an ink jet printer, it is necessary to arrange the ink jet nozzles at a high density in the row direction, and in practice, such a structure has been difficult. That is, when the line nozzle head is configured by an inkjet printer, the ink path becomes thin due to the high density arrangement, and as a result, there is a problem that clogging, defective ink ejection, and the like occur. Further, in a printer using an electrostrictive element for ejecting ink, it is not possible to obtain a structure in which a displacement amount of the electrostrictive element for obtaining a required volume change for each nozzle is secured in a high-density nozzle structure. was there.

Several proposals have been made in the past in order to eliminate the difficulty of such a line printer.

For example, it is possible to provide a substantially double-density line type printer by stacking two stages of ink jet heads arranged in a row direction at a relatively low density and staggering the positions of both nozzles.

However, in this double layered head,
The total number of inkjet nozzles is the same as that of the high-density head, manufacturing of the entire head is complicated, and a low-cost printer cannot be obtained.

For high density only, for example, the ink nozzles may be arranged obliquely to increase the distance between the nozzles to facilitate precision machining, or a plurality of heads may be arranged with a shifted pitch. However, in any case, the data processing at the time of printing becomes complicated, and when the number of nozzles themselves is large as in the above-described conventional apparatus, the manufacturing cost is increased even if the structure is slightly simplified. It did not lead to reduction, and was not very feasible as a practical device.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to reciprocate the entire head in the row direction within a dot interval while the nozzle density in the ink jet head is relatively low. It is an object of the present invention to provide an improved inkjet printer capable of high-speed and high-density printing by using a low-density nozzle head by being configured as a so-called shuttle type printer that operates.

[0011]

In order to achieve the above object, an ink jet printer according to the present invention is carried by a carriage in a state of facing a paper, and a plurality of ink jet nozzles are arranged at a dot pitch P at equal intervals in a row direction. Inkjet heads arranged in a row, a head feed mechanism for moving the inkjet heads in the row direction within the dot pitch P by a predetermined division pitch p, and the paper when the inkjet head is stationary at the division dot positions determined by each division pitch. And a paper feeding mechanism for controlling feeding or returning within a predetermined feeding range.

Further, the ink jet printer according to the present invention is carried by a carriage in a state of facing a paper, and a plurality of ink jet nozzles are arranged in a row direction at a dot pitch P of equal intervals, and the ink jet head is a dot. A head feed mechanism that moves a predetermined division pitch p in the row direction within the pitch P, a head column direction movement mechanism that moves the inkjet head in the column direction within a predetermined movement range, and a paper feed mechanism that controls the paper feed. It is characterized by including.

[0013]

Therefore, according to the present invention, while the ink jet head is stationary at the predetermined divided dot position, the paper is fed and driven in the predetermined feed range in the feed direction, and then the ink jet head is moved in the row direction by the division pitch p. It is possible to print at a high density by moving the sheet, returning the sheet in the returning direction to the predetermined feeding range again at this divided dot position, and repeating this.

Further, the paper is fed to a predetermined position by the paper feeding mechanism, the inkjet head is moved in the row direction by the division pitch p, and the inkjet head is moved within the predetermined movement range at the division dot position by a predetermined distance in the row direction. It was possible to print at high density by moving and repeating this.

As a result, according to the present invention, it is possible to move between the dot pitches P by the divided dot pitch p even with a relatively low density ink jet nozzle arrangement, so that it is possible to perform sufficiently high density printing. .

In particular, according to the present invention, although the principle of the conventional shuttle type printer is used, the printing procedure itself is such that the paper feed or return control is performed while the ink jet head is stationary at each divided dot position. The principle is different from the structure in which the inkjet head is controlled to move in the row direction by a predetermined distance at a predetermined range or at the divided dot position, and the head shuttles back and forth with the paper fixed in the conventional shuttle printer. There is.

The printer according to the present invention is particularly suitable for printing labels such as bar codes or block codes.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

(1) Embodiment of the Invention According to Claim 1 FIG. 1 shows a preferred embodiment of the ink jet printer according to the invention described in claim 1, in which the paper 11 is along the platen 10 in the direction of arrow ab. The paper is being fed or is being driven back. In this embodiment, the platen 10 is made of a flat plate, and the inkjet head 12 is provided on the platen 10 with the paper 11 sandwiched therebetween. The inkjet head 12 has a plurality of ink nozzles 13 arranged at predetermined intervals in the row direction cd as shown in the drawing. The interval between the nozzles 13 is equal to the dot pitch P.
Indicated by.

As is apparent from FIG. 1, the paper 11 in this embodiment is a label paper, and bar code labels 11a are sequentially arranged on the roll paper in a peelable manner.

The ink jet head 12 is fixed to a carriage 16 movable in the row direction by two guide shafts 14 and 15. The carriage 16 moves the ink jet head 12 in the arrow cd direction within the range of the dot pitch P. You can move to.

The head feed mechanism is a mechanism for moving the dot pitch P in the row direction cd by a predetermined division pitch p. In the embodiment, the head feed mechanism is always provided on the carriage 16 with an arrow c. Biasing spring 17 for giving a biasing force in the direction and left side wall 16 of carriage 16
and a feed cam 18 for pressing a. That is, the carriage 16 is always urged in the direction of arrow c by the urging spring 17 with the inkjet head 12 being carried, and its position is determined by the angle of the feed cam 18. Therefore, the feed cam 18 has an eccentric cam shape,
Although the eccentric feed cam 18 is not shown in detail, the eccentric feed cam 18 moves the position of the carriage 16 within the dot pitch P by intermittently feeding by 90 ° in the embodiment by a pulse motor or a rotary encoder. It is possible to control the movement to the predetermined four divided dot positions.

FIG. 2 shows the operation of the head feed mechanism according to the first aspect of the present invention, and the eccentric feed cam 18 is shown in FIG.
By rotating 90 ° at a time as in C and D, the position of the carriage 16 is sequentially fed and driven by the division pitch p in the direction of the arrow d. In the embodiment, for example, the nozzle 13 in the inkjet head 12 described above is used.
If the dot pitch P is 0.5 mm, the divided dot positions shown in FIG.
The carriage 16, that is, the inkjet head 12 can be fed and driven to each divided dot position at a division pitch p of 5 mm.

Therefore, in the embodiment, even if the nozzle array has a relatively low density of 0.5 mm dot pitch, the ink jet head 12 can be positioned at the 1/4 division dot position as described above, and therefore the actual print density can be obtained. Can be densified.

At each of the divided dot positions,
According to the invention described above, the paper 11 is controlled to be fed in the direction a or returned in the opposite direction b, and the feeding range is set to the arrangement pitch of the labels in the label printer of the embodiment.

In order to reciprocate the paper 11 as described above, a normal paper feeding mechanism is also used in this embodiment. In the embodiment, the feeding and returning rollers 19 and 2 are also used.
No. 0 is provided, and tension rollers 21 and 22 are arranged on both drive rollers 19 and 20 with a predetermined pressing force sandwiching the paper 11.

Therefore, when the paper 11 is fed normally, and when the print is fed in the direction of the arrow a at each divided dot position of the ink jet head 12, the roller 1 is used.
9 drives the paper 11 at a predetermined speed in the direction of a predetermined feed amount arrow a. At this time, the roller 20 gives a slight load to the paper 11 in order to give a free or predetermined back tension.

On the other hand, the paper 11 is returned to the arrow b for printing.
In order to return to the direction, the roller 20 drives the paper 11 back in the direction of the arrow b, and at this time, the roller 19 becomes free or a predetermined back tension is applied to the paper 1.
Load 1

FIG. 3 shows a label 1 according to the invention of claim 1.
When the nozzle 13 of the inkjet head 12 is at the divided dot position A, the sheet is fed and driven in the direction of the arrow to perform printing along the print line 101. Then, after the completion of the predetermined feeding range, the head 12
Is driven to be driven in the direction of arrow d to the position B by the rotation of the eccentric feed cam 18 by 90 °, where the paper is driven back in the direction of arrow b, at which time printing is performed along the print line 102. Similarly, the head 12 is sequentially fed to the divided dot positions C and D by the eccentric feed cam 18. By feeding and returning the paper 11, the printing along the printing lines 103 and 104 at this time is performed. In this way, while using the ink jet nozzles 13 arranged at a relatively low density, the head is fed in the row direction between the dot pitches to enable the desired printing action at the divided dot positions. Can be densified.

The above-described embodiment is an embodiment in which the ink jet printer according to the invention described in claim 1 is used as a label printer. However, not only the present invention but also ordinary character / symbol or numeral data is printed at high density. FIG. 4 shows a control circuit diagram of the ink jet printer according to the present invention having a page memory for storing one page of data.

In the figure, since the ink jet head 12 is moved in the row direction by the eccentric feed cam 18, the feed cam 18 is driven by the pulse motor 30 and the CPU 3
1 controls the drive of the motor 30 via the drive circuit 32. The print data is stored in the page memory 33, and the content is 16 rows × 16 columns as shown in FIG.
It has 00 × 2240 memory cells and internally stores dot information for one page. The CPU 31 reads, from the page memory 33, the necessary data for one line, that is, the line data corresponding to the divided dot positions where the inkjet nozzles 13 are statically positioned,
This is stored in the row register 34, and the ink ejection of the inkjet head 12 is controlled by the content of the row register 34.

The CPU 31 further drives and controls the motor 36 via the drive circuit 35, and thereby rotationally drives the above-mentioned feed and return rollers 19 and 20 to determine the feed position of the paper 11.

FIG. 6 is a flowchart showing the printing operation in this embodiment.

In step ST1, the ink jet nozzle 13 is at the leftmost position A, and at this time the CPU 31
From page memory 33 to 4 from the left end of one line of memory
The data for each column is read and stored in the row register 34. The ink jet head 12 has all the nozzles 13.
Jet control is performed in accordance with the contents of the row register 34 (ST2), and then the CPU 3 is operated after printing is completed.
1 determines whether this print is the last line of the page memory 33 (ST3). When the content of the page memory 33 is not the last line, the CPU 31 causes the motor 36 to rotate the roller 1
9 and 20 are driven to feed the paper for one line in the memory 33 (ST4). Then, the CPU 31 again reads the data every four columns from the left end of this new row (ST
5) This is sent to the row register 34, and printing is performed again in ST2. The above operation is sequentially repeated, whereby the printing of every four columns for one page at the divided dot position A is completed. In this state, the paper 1 of FIG.
1 is shown as print line 201.

In step 3 (ST3), when printing up to the last line of the divided dot position A is completed, the CPU 31
Rotates the eccentric feed cam 18 by 90 ° by the motor 30 and moves the head 12 right by one row (ST6). As a result, the nozzle 13 of the head 12 moves to the divided dot position B.
It has been moved to. And this divided dot position B
In the same way, the data in every 4 columns from the second column from the left end of the last row of the page memory 33 is read out and the row register 3
4 is stored (ST7). In this state, the CPU 31 issues a print command to the inkjet head 12 (ST
8) Next, it is determined whether or not this print line is the first line of the page memory 33 (ST9). If the printing at this time is not the first line, the CPU 31 gives a drive command to the motor 36,
Using the rollers 19 and 20, one line of the page memory 33,
The sheet 11 is fed back (ST10). Then, in the next line, new data is read again (ST11) as in step 7 (ST7) and printed (ST).
8). Then, this print line indicates a line print for one page at the divided dot position B, as indicated by reference numeral 202 in FIG. 7.

Then, the print line 202 is changed to the page memory 33.
When the first row of the
Is moved to the right by one column to move to the next divided dot position C (ST12).

As described above, the divided dot position C is again obtained.
The paper 11 is fed at, then the paper is fed back at the divided dot position D, and the desired print lines 203, 204
Printing is completed, which completes high-density printing using the low-density head.

According to this embodiment, in order to print, for example, A4 size (280 mm), if the print cycle of the head 12 is 0.2 mm second, {(0.2 ms × 8 dots / mm) × 280 (mm )}
X4 = 1.792 (seconds), and one page can be printed in about 5 seconds.

(2) Embodiment of Invention of Claim 2 FIG. 8 is a perspective view showing a preferred embodiment of an ink jet printer according to the invention of Claim 2. It should be noted that the same components as those in FIG.

The ink jet printer has four guide shafts 40, 41, 42, 43 extending in the vertical direction, and these guide shafts 40, 41, 42, 43 make a slide guide 44 having a U-shape in a front view. Are guided in the vertical direction ab. Then, the slide guide 44
Is fixed to a timing belt 47 wound around pulleys 45 and 46 arranged above and below, and a step motor 48 is connected to the pulley 46. Therefore, the timing belt 47 rotates a predetermined amount in the ab direction when the step motor 48 rotates a predetermined amount, and the slide guide 44 moves up and down ab by the predetermined amount rotation of the timing belt 47.
It is configured to slide along the guide shafts 40, 41, 42, 43 in a predetermined direction by a predetermined distance. The guide shaft 4
0, 41, 42, 43, pulleys 45, 46, step motor 48, and slide guide 44 constitute a head column direction moving mechanism.

Two guide shafts 14 and 15 are supported on the slide guide 44 substantially horizontally and in parallel, and the inkjet head 12 is slidably supported in the cd direction by these guide shafts 14 and 15. The carriage 16 can move the inkjet head 12 in the arrow cd direction within the range of the dot pitch P.

The head feed mechanism is a mechanism for moving the dot pitch P in the row direction cd by a predetermined division pitch p. In the present embodiment, the head feed mechanism is provided on the carriage 16 with an arrow. It is composed of a biasing spring 17 whose one end that applies a biasing force in the c direction is fixed to the slide guide 44, and a feed cam 18 that presses the left side wall 16a of the carriage 16. That is, the carriage 16 is always urged in the direction of arrow c by the urging spring 17 with the inkjet head 12 being carried, and its position is determined by the angle of the feed cam 18. Therefore, the feed cam 18 is formed into an eccentric cam shape, and although the eccentric feed cam 18 is not shown in detail in the drawings, the eccentric feed cam 18 is formed by a pulse motor or rotary encoder in the embodiment.
By intermittently feeding by 0 °, the eccentric feed cam 18 can control the position of the carriage 16 to be divided into four divided dot positions defined within the dot pitch P.

Next, the operation of this embodiment will be described.

When the label 11a is printed, when the nozzle 13 of the ink jet head 12 is at the divided dot position A, the slide guide 44 is vertically moved by the timing belt 47 which is rotated by the rotation of the step motor 48. Then, the slide guide 44 is moved in the direction of the arrow to print along the print line 101. Then, after the slide guide 44 has moved a predetermined distance, the head 12 is driven and driven to the position B in the arrow d direction by the 90 ° rotation of the eccentric feed cam 18, where the slide guide 44 is moved in the arrow b direction. The printing is performed along the print line 102. Similarly, the head 12 is sequentially fed to the divided dot positions C and D by the eccentric feed cam 18. By moving the slide guide 44 in the arrow a direction or the b direction, the print line 103 at this time,
Printing according to 104 is performed. In this manner, while using the inkjet nozzles 13 arranged at a relatively low density, the head is fed in the row direction between the dot pitches,
Since the desired printing action is possible at the divided dot positions,
It is possible to increase the density of actual printing.

Therefore, in the present embodiment, unlike the embodiment of the invention described in claim 1, it is not necessary to reciprocate the paper 11, and the head 12 is mechanically moved to improve the repeat accuracy. , The print quality is improved.

[0046]

As described above, according to the present invention,
High-density printing can be performed using a low-density line-type inkjet head that is easy and inexpensive to manufacture, and high-speed high-density printing can be performed with a head having a simple structure. Therefore, according to the present invention, high-speed printing can be performed with a small amount of electric power, so that it is possible to provide a miniaturized inkjet printer driven by a battery.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts showing a preferred embodiment of an inkjet printer according to the invention of claim 1.

FIG. 2 is an explanatory diagram showing a row direction movement operation of the head in the embodiment.

FIG. 3 is an explanatory diagram showing a state of head feeding and paper feeding when label printing is performed in the embodiment.

FIG. 4 is a block diagram of a preferred print control circuit of the present invention.

5 is an explanatory diagram showing an example of a page memory in FIG.

FIG. 6 is a flow chart for driving the control circuit of FIG.

FIG. 7 is an explanatory diagram showing a printing operation for one page according to the flowchart of FIG.

FIG. 8 is a perspective view of an essential part showing a preferred embodiment of the inkjet printer according to the invention of claim 2.

[Explanation of symbols] 10 platen 11 paper 12 inkjet head 13 inkjet nozzle 14, 15 guide shaft 16 carriage 17 biasing spring 18 eccentric feed cam 19 feed roller 20 return roller 40, 41, 42, 43 guide shaft 44 slide guide 44 45 , 46 pulley 48 step motor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area 8804-2C B41J 3/12 G

Claims (2)

[Claims] 1. An inkjet head in which a plurality of inkjet nozzles are arrayed in a row direction at a dot pitch P at equal intervals, the inkjet head being supported by a carriage in a state of facing a sheet, and the inkjet head is predetermined in the row direction within the dot pitch P. A head feed mechanism that moves the division pitch p, and a paper feed mechanism that controls the feed or return of the paper within a predetermined feed range when the inkjet head is stationary at the division dot position determined by each division pitch. Inkjet printer characterized by. 2. An inkjet head in which a plurality of inkjet nozzles are arrayed in a row direction at a dot pitch P at equal intervals, the inkjet head being supported by a carriage in a state of facing a sheet, and the inkjet head is predetermined in the row direction within the dot pitch P. An inkjet printer including: a head feed mechanism that moves the division pitch p; a head column direction movement mechanism that moves the inkjet head in a column direction within a predetermined movement range; and a paper feed mechanism that controls the paper feed. .