JPH05301377A - Recording head - Google Patents

Abstract

PURPOSE:To simplify construction and reduce cost. CONSTITUTION:A plurality of nozzle driving parts 20, of which each part is equipped with a nozzle, are divided into two nozzle driving groups such as an old number group and an even number group. An odd number signal P1 being a driving signal of the odd number nozzle driving part group and an even number pulse signal P2 being a driving signal of the even number nozzle driving part group are made to have a switching waveform which drives each nozzle driving part group at different timing. For odd number nozzle driving parts 20 and even number nozzle driving parts 20, a driving circuit 22 is commonly by used (driving them by switching pulse signals P1, P2 with a switch driving circuit 23, and its structure will be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head applied to serial printers such as ink jet printers, thermal printers and dot impact printers.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing the basic construction of an ink jet printer, in which 1 is a recording head (print head).
Head main body 3 in which the head main body 1 is mounted, 4 is a main scanning direction of the carriage 3 (arrow X
A pair of guide shafts 5 for guiding the movement of the platen roller, which is rotationally driven by a drive gear 6, and 7 is a recording sheet.

In FIG. 1, the carriage 3 is moved in the main scanning direction X by receiving the driving force of a carriage driving motor (not shown), so that the print head 2 is scanned in the main scanning direction X. Further, the platen roller 5 is rotated in the sub-scanning direction Y by the drive gear 6 to feed the recording paper 7.

FIGS. 5 (a) and 5 (b) are explanatory views showing the structure of a print head for a conventional ink jet printer.
In FIG. 5A, a plurality of (n) noises 8 for ejecting ink as droplets are installed in a direction perpendicular to the main scanning direction X, and FIG. It is installed so as to be inclined with respect to the scanning direction X.

FIG. 6 is an explanatory view of a conventional nozzle driving section, in which n nozzle driving sections 9 provided with nozzles 8 are respectively connected to n driving circuits 11 via n connecting cables 10.
Independently connected to. Incidentally, D _{1 to} D _n in the figure are print data.

Since each nozzle 8 is provided with a drive unit 9, as shown in the timing chart of FIG. 7, the print data D _{1 to} D _{n are} printed at the positions of the print dots 12.
All nozzles were driven at once based on the.

[0007]

In the above-mentioned conventional technique, n connection cables 10 are provided corresponding to n nozzles 8.
And a drive circuit 11 are required, and the structure of the nozzle drive portion is complicated and the cost is increased in proportion to the number of nozzles 8.

An object of the present invention is to provide a recording head which can be simplified in structure and can be reduced in cost.

[0009]

In order to achieve the above object, the present invention provides a plurality of nozzles for an ink jet printer which is a dot forming section, a print heat generating section for a thermal printer, and a dot wire for a dot impact printer. It is characterized in that the drive signal of each dot forming portion group is a switching waveform for driving at a different timing for each dot forming portion group.

Further, the odd-numbered dot forming section and the even-numbered dot forming section are commonly used, and the driving sections are switched and driven at different timings to perform dot printing.

Further, the drive off time t _{off of the} drive signal
And the mechanical time constant or thermal time constant t _m of the recording head
It is characterized in that (t _off / t _m ) is smaller than 1/3.

[0012]

According to the above-mentioned means, the nozzle for the ink jet printer, the print heating portion for the thermal printer, and the dot wire for the dot impact printer are divided into a plurality of dot forming portion groups, for example, odd-numbered dot formation. Part and the even-numbered dot forming part can be used in common and can be switched and driven at different timings for each dot forming part group to perform dot printing. Can be reduced.

Even if the switching drive is performed at different timings as described above, the ratio (t _off) of the drive off time t _off in the drive signal of the dot forming section and the mechanical time constant or thermal time constant t _m of the recording head. By making / t _m ) smaller than 1/3, it is possible to prevent the recording head from returning to the initial state within the drive-off time, and prevent defective dot formation during one cycle of the recording operation.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a nozzle driving portion of a print head for an ink jet printer which is an embodiment of the present invention. The nozzle 8 in the installed state shown in FIG. 5 (a) or 5 (b) is shown. In the present embodiment, the n nozzle driving units 20 provided with are paired with even-numbered and odd-numbered nozzles 8 which are adjacent to each other, and drive circuits (n / 2) via connection cables (n / 2), respectively. / 2) connected to 22.

D _{1 to} D _n are dot signals, which enter the drive circuit 22 as print data corresponding to print character or graphic data, and drive the nozzle drive section 20.

Reference numeral 23 denotes a drive signal composed of an odd pulse signal P ₁ and an even pulse signal P ₂ which are switching waveforms for switching the active time t _on and the inactive time t _off shown in FIG. 2 at different timings. , A switching drive circuit for sending to the odd-numbered and even-numbered nozzle drive units 20, respectively, wherein the odd-numbered pulse signal P ₁ is connected to the common line C ₁ of the odd-numbered nozzle-driving unit 20, and the even-numbered pulse signal P ₂ is even-numbered. Is connected to the common line C ₂ of the nozzle drive unit 20 of FIG.

Numeral 24 is a data switch which, when the odd pulse signal P ₁ is active, makes the odd print data D ₁ , D ₃ , ... Valid, and when the even pulse signal P ₂ is active, The odd-numbered print data D ₁ , D ₃ , ... Are separated and the even-numbered data D ₂ , D ₄ ,.

Next, the operation of the above embodiment will be described.

Odd pulse signal P ₁ and even pulse signal P
_As shown in FIG. 2, ₂ is output at the period t ₁ and the switching time t ₂ , and the print data D ₁ , D ₂ ,
.., D _n are input, first, t _{on of the} odd pulse signal P ₁
, The even-numbered pulse signal P ₂ is t _off , so the odd-numbered print data (D ₁ , D ₃ , ...) Is valid, the odd-numbered nozzle drive unit 20 is driven, and the odd-numbered nozzles are driven. 8 is excited.

Next, when the odd pulse signal P ₁ becomes t _off ,
Since the even pulse signal P ₂ is t _on, the even-th print data _{(D 2, D 4, ...} ) becomes effective, so that the even-numbered nozzles 8 in the same manner as described above is excited. In this way, the nozzle 8 is excited for the required time (t ₂ ) repeatedly, and one printing cycle is completed.

In the timing chart of FIG. 2, taking the _first and second print data D ₁ and D ₂ as an example, the print data D ₁ and D ₂ are turned on at the first input and the print data D ₂ at the second input. It shows the case where it is turned on only.
The output data D ₁ and D ₂ to the second nozzle drive unit 20 are active for (t ₂ + t _on ) time at the first time and t at the second time.
The waveforms are _on and t _off . The first and second nozzle drive units 20 are both driven at the first time, and only the second nozzle drive unit 20 is driven at the second time, and the nozzle 8 is driven by the drive of this nozzle drive unit 20. You will be excited.

As described above, by dividing the nozzle 8 into n and switching the drive signal, the connection cable 21 and the drive circuit 22 can be reduced compared to the conventional example, and the cost can be reduced.

In the above embodiment, the dot forming portion of the print head has been described as the nozzle 8 for the ink jet printer, but by using the dot forming portion as the print heat generating portion, it can be applied to the print head of the thermal printer. Further, by using a dot wire for the dot forming section, it can be applied to a print head for a dot impact printer.

Further, in the above-mentioned embodiment, the nozzle 8 which is a dot forming portion is divided into two even-numbered and odd-numbered dot forming portion groups. However, the dividing method is not limited to the above two divisions, and the number of divisions is not limited to this. If the number is further increased, the number of constituent members can be further reduced.

By the way, as shown in FIGS. 3 (a) to 3 (c), active (driving) time t _on and inactive time t _off in the odd pulse signal P ₁ and the even pulse signal P ₂ ,
The relationship between the mechanical time constant of the print head (when the dot forming part is the nozzle or the dot wire) or the thermal time constant (when the dot forming part is the print heat generating part) t _{m (1, 2)} is shown in FIG. ) 、
As in (b), when t _off > t _m1 , pulse signals P ₁ and P ₂
There also rises at t _on, will revert to the initial state at t _off during or between which does not reach a predetermined printing temperature, the dot formation section does not reach the predetermined printing position and start-up the next t _on The target position and temperature will not be reached no matter how many times it is repeated.

However, as shown in FIGS. 3 (a) and 3 (c), t _off ≤
In the case of t _m2 , since the dot forming portion does not return to the initial state, the target printing position or printing temperature can be reached. Therefore, it is desirable to set the relationship of t _off / t _m ≦ 1/3.

[0028]

As described above, according to the present invention,
Driving the dot forming unit by dividing the plurality of dot forming units in the inkjet printer, the thermal printer, and the dot impact printer into a plurality of dot forming unit groups and driving each dot forming unit group at different timings. It becomes possible to make the parts common, and even if they are driven at different timings as described above, the drive off time t _off in the drive signal of the dot forming part and the mechanical time constant or thermal time constant t of the recording head are Ratio with _m (t _off /
By making t _m ) smaller than 1/3, the recording head does not return to the initial state within the drive off time, normal recording operation is possible, the configuration can be simplified and cost can be reduced. It is possible to provide various recording heads.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a nozzle driving portion of a print head for an inkjet printer that is an embodiment of the present invention.

FIG. 2 is a timing chart of printing in this embodiment.

FIG. 3 is a timing chart for explaining a relationship between a pulse signal and a time constant.

FIG. 4 is a perspective view showing a basic configuration of an inkjet printer.

FIG. 5 is an explanatory diagram showing a configuration of a print head for an inkjet printer.

FIG. 6 is an explanatory diagram of a conventional nozzle driving portion.

FIG. 7 is a timing chart of printing in the nozzle driving portion of FIG.

[Explanation of symbols]

2 ... Print head, 8 ... Nozzle (dot forming part), 20 ...
Nozzle drive part, 21 ... Connection cable, 22 ... Drive circuit,
23 ... Switching drive circuit, 24 ... Data switching device, P ₁ , P ₂ ...
Pulse signal (driving signal).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location B41J 2/30 9012-2C B41J 3/04 103 N 9211-2C 3/10 114 D

Claims (6)

[Claims] 1. In a recording head having a plurality of dot forming sections, the dot forming section is divided into a plurality of dot forming section groups, and a drive signal of each dot forming section group is supplied to each dot forming section group. A recording head having a switching waveform that is driven at different timings. 2. The recording head according to claim 1, wherein the dot forming portion is a nozzle for an ink jet printer that ejects ink as droplets. 3. The recording head according to claim 1, wherein the dot forming section is a print heating section for a thermal printer. 4. The recording head according to claim 1, wherein the dot forming section is a dot wire for a dot impact printer. 5. The dot printing is performed by making the driving units of the odd-numbered dot forming units and the even-numbered dot forming units common and switching the driving units at different timings to drive them. 1 recording head. 6. A drive off time t _{off of the} drive signal,
The ratio of the mechanical time constant of the recording head or the thermal time constant t _m (t
_2. The recording head according to claim 1, wherein _off / t _m ) is smaller than 1/3.