JP3350303B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly, to an ink jet recording apparatus in which a plurality of individual ink chambers each having a nozzle are arranged adjacent to each other to suppress crosstalk.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, dot recording is performed by ejecting ink droplets from nozzles of an ink jet head and attaching the ink droplets to a recording medium such as printing paper. In order to express characters, symbols, and the like using the dot pattern, multi-channel nozzles are arranged on a straight line, and ink is ejected from the nozzles according to print data. By the way, since the ink ejection is performed by pressurizing the ink chamber communicating with the nozzle of the ejecting channel by deformation of the electrostrictive element, the application of the driving voltage to a certain channel is performed not only to the channel but also to an adjacent channel. Affected, so-called crosstalk is a problem.

[0003] An example of an ink jet recording apparatus for reducing this crosstalk is described in Japanese Patent Publication No. 59-33117. In the ink jet recording apparatus described as an example in this publication, the timing of the drive voltage to the electrostrictive element is set to 1 between adjacent channels as shown in FIG.
The two adjacent channels are prevented from being driven simultaneously by performing three-division driving with a shift of / 3 cycle. When two adjacent channels are simultaneously driven, a small amount of ink is ejected from the adjacent non-driven channels due to crosstalk, which is prevented.

[0004]

In recent ink jet recording apparatuses, it is desired to further improve the printing quality and the printing speed. Further, there is a demand for downsizing of the head unit, which leads to downsizing of the apparatus body. With respect to the above-mentioned requirements, with respect to the configuration of the head, higher resolution and smaller head unit correspond to increasing the array density of the channels of the head, and improving the printing speed corresponds to increasing the number of channels. In fulfilling this requirement, considering the effects of crosstalk, the crosstalk includes the effects of the propagation of pressure waves generated in the drive channel and the effects of deformation of the channel itself. Both of these effects are related to the magnitude of their propagation and the spatial distance to the drive channel. Therefore, the above-mentioned requirement is such that the influence of crosstalk is even greater and covers a wider range. Therefore, the split driving alone is not enough to buffer the influence of crosstalk.

In the above-described ink jet recording apparatus, when there are many (3n) channels, no consideration is given to crosstalk between simultaneously driven channels. In other words, the speed of the ink to be ejected is different between the case where the drive channel is used alone and there is no drive channel in the vicinity, and the case where the drive channel is used nearby and another drive channel is used and the crosstalk is applied. The difference in the ink speed causes the position where the ink is attached on the recording medium to shift, which causes the quality of the recording result to deteriorate.
In this ink jet recording apparatus, only two channels at other timings exist between the channels driven at the same timing. Therefore, if the channels with the two channels interposed are driven at the same time, the influence of the crosstalk is reduced. It will happen.

This will be described with reference to the graph of FIG.
This graph shows a change in the ink speed when the number of simultaneously driven channels on both sides of the channel is increased based on the ink speed (5 m / sec) when only a certain channel is driven alone. is there. In this graph, an increase of 0.4 m / sec with respect to the reference speed can be seen when "one on both sides", that is, the measurement channel and one channel on both sides thereof are simultaneously driven. This is the contribution of crosstalk from the immediate neighbor. Then, when "two adjacent sides", that is, the measurement channel and two channels on both sides thereof are simultaneously driven, a speed increase of 0.2 m / sec is observed with respect to "two adjacent sides". Then, when "two adjacent sides", that is, three channels on both sides of the measurement channel are simultaneously driven, a speed increase of 0.1 m / sec is observed with respect to "two adjacent sides".

[0007] In the graph of FIG. 8, the acceleration is no longer observed after “5 on both sides”, so that it is necessary to provide at least four channels between them in order to make the influence of crosstalk negligible. . To achieve this by increasing the number of drive divisions, five or more divisions are required, which makes the control system very complicated. further,
Increasing the number of drive divisions increases the displacement of the ink attachment position on the recording medium. In order to correct this shift, it is conceivable to shift the opening position of the nozzle. However, this is contrary to the demand for downsizing the head and increases the cost.

There is another problem in increasing the number of drive divisions. If the number of drive divisions is large, the drive time of the channel immediately adjacent may partially overlap. In particular,
In today's inkjet printing apparatuses that require high-speed printing, the ratio AL / TL of the on-time (indicated by AL in FIG. 7) of the drive signal to the drive cycle (indicated by TL in FIG. 7) is compared. It is unavoidable that the driving time is duplicated. If the number of divisions is 5, for example, 1 → 3 →
An arrangement such as 5 → 2 → 4 can reduce duplication, but is not necessarily a solution for the following reasons.

FIG. 9 is a graph showing the result of measuring the effect on ink speed due to overlapping of drive times between adjacent channels. In this graph, the vertical axis represents the ink speed, and the horizontal axis represents the drive time deviation ratio ΔAL / AL. ΔAL represents a time difference from the rise of the drive pulse of the channel to be measured to the rise of the drive pulse of the adjacent channel. Here, AL is 10μ
The measurement was performed under the condition that ink speed of 5 m / sec can be obtained if the ink is ejected independently. From this graph, ΔAL / A
When L is 0, that is, when the drive times of both channels completely match, it is read that the ink speed is the fastest. But not only that, ΔA
It is also read that when the absolute value of L / AL approaches 1, that is, when the ratio of the overlapped portion is small, there is a negative crosstalk in which the ink speed is rather slower than that in the case of single ejection. That is, it is not always possible to say that the effect of crosstalk is small if the overlap of the drive time between the two channels is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and high quality recording results can be obtained by effectively eliminating crosstalk without excessively increasing the number of drive divisions. An object of the present invention is to provide an ink jet recording apparatus as described above.

[0011]

According to the present invention, there is provided an ink jet recording apparatus for ejecting ink from a plurality of nozzles onto a recording medium to perform recording.
The above-described separated common ink chambers and adjacent ones
Receive ink from different common ink chambers
They are arranged in a substantially column, and a plurality of the individual ink chambers, wherein the nozzle is provided in each, and a pressurizing means for pressurizing the individual ink chamber of the ink provided to each of the individual ink chambers, the individual ink Individual inns adjacent to each other in the row direction
Drive means for applying a drive signal at a different timing for each group while dividing each of the pressurizing means into three or more groups so that the pressurizing means of the work chamber do not belong to the same group , the number of the common ink chamber and the number group of said pressurizing means, both Ri number der other than times other integer, one group
One common ink chamber corresponding to the pressure means
Between the two individual ink chambers connected to the ink chamber, another shared
Make sure that the individual ink chambers connected to the
Characterized in that was.

(2) The present invention is the ink jet recording apparatus according to the above (1), wherein the number of the common ink chambers and the number of the groups of the pressurizing means are relatively prime.

(3) The present invention is characterized in that in the ink jet recording apparatus according to the above (1) or (2), the pressurizing means deforms a wall portion of the individual ink chamber.

In the ink jet recording apparatus of (1) or (2), when a drive signal is applied to the pressurizing means by the drive means, the ink in the individual ink chamber is pressurized by the pressurizing means. Therefore, ink is ejected from the nozzles of the individual ink chambers onto the recording medium, and recording is performed. Here, the individual ink chambers, so as not to receive a supply of ink that adjacent the same common ink chamber, conversion
In other words, ink from adjacent common ink chambers is different.
Since the ink chambers are arranged substantially in a row so as to receive the ink supply, no crosstalk occurs between adjacent individual ink chambers. Further, pressure means are adjacent in the column direction of the individual ink chambers
The pressure means of the individual ink chambers
In odd, is divided into three or more groups, and application of the drive signal to the pressurizing means by drive means, since it is made at different timings in the group your capital, the supply of ink from the same common ink chamber And at least one other individual ink chamber is the least common multiple of the number of common ink chambers and the number of pressurizing means groups between the individual ink chambers receiving and driven by the same timing signal. , And crosstalk hardly occurs. Here, since both the number of the common ink chambers and the number of the group of the pressurizing means are numbers other than the integral multiple of the other, the least common multiple of these is larger than any of them. Therefore, crosstalk is effectively suppressed without excessively increasing the number of common ink chambers and the number of pressurizing units.

In particular, as in the ink jet recording apparatus of (2), if the number of the common ink chambers and the number of the pressurizing means are relatively prime, that is, they have no common divisor other than 1, the least common multiple of these is given. Is equal to the product of these, and the crosstalk can be more effectively suppressed without excessively increasing the number of common ink chambers and the number of pressurizing units.

Further, in the ink jet recording apparatus of (1) or (2), as in (3), the ink can be ejected by the pressing means deforming the wall portion of the individual ink chamber.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the ink jet recording apparatus of the present invention will be described below in detail with reference to the drawings.

In the schematic perspective view of FIG. 1, a cylindrical platen roller 62 for conveying a printing paper S is provided in a casing 60 of the ink jet recording apparatus so as to be rotatable around an axis. A guide rod 64 and a guide rail 66 are arranged in parallel with the platen roller 62, and are provided so that the carriage 9 can move in parallel with the platen roller 62 while being supported by these.

The carriage 9 has a multi-channel ink jet head 10 for ejecting ink and an ink tank 12 for supplying ink. The carriage 9 is driven via a belt 70 by a CR motor 68 provided at a lower portion in the casing 60. Further, in the casing 60, a wiper 72, a purge pump 74, and a purge cap 76 are provided as a mechanism for recovering when the ink ejection state of the inkjet head 10 deteriorates.

As shown in FIG. 2, the ink jet head 10 has a piezoelectric ceramic plate 102, a cover plate 110, and a nozzle plate 114.

The piezoelectric ceramic plate 102 is formed of a lead zirconate titanate (PZT) -based ceramic material, and has a plurality of parallel grooves 103 having the same depth and cut by a diamond blade or the like. The partition 106 between the grooves 103 is polarized in the direction of the arrow 105. Metal electrodes 108 are formed on the upper half of both sides of each groove 103 by sputtering or the like. The cover plate 110 is formed of a ceramic such as alumina, and is adhered to the upper surface of the piezoelectric ceramic plate 102 with an epoxy-based adhesive.
03 is sealed. The grooves 103 whose upper surfaces are sealed by the cover plate 110 are alternately
Alternatively, it is used as the air chamber 127.

The nozzle plate 114 is made of plastic and is adhered to the front surfaces of the piezoelectric ceramic plate 102 and the cover plate 110. This nozzle plate 1
14 has nozzles 112 at positions corresponding to the individual ink chambers 104. Although only three individual ink chambers 104 and three nozzles 112 are shown in FIG. 2, actually, the number of the individual ink chambers 104 and the number of the nozzles 112 are larger, and they are arranged substantially in a line.

The ink jet head 10 has an ink manifold 14 for supplying ink from the ink tank 12 to the individual ink chamber 104. As shown in FIG. 3, the ink manifold 14 includes the individual ink chambers 1.
Outlet 1 connected to the end opposite to nozzle 112 of nozzle 04
A plurality of (for example, two) common ink chambers 18 and 19 are formed so as to extend in the column direction between the rows of 81 to 188 and 191 to 198.
A large number of branch paths are formed in a comb-like shape from 8, 19 to each feed port. Each feed port 181 to 188 and 191 to
198 is connected to the common ink chambers 18 and 19 which are sequentially different in the row direction of the feed port so that those adjacent to each other do not receive ink supply from the same common ink chamber. That is, when there are two common ink chambers, different common ink chambers are alternately connected to the feed ports in the column direction.

Each of the common ink chambers 18 and 19 is connected at one end to the ink tank 12 via the receiving port 16 and receives supply of ink from the ink tank. Interconnected feed ports, individual ink chambers 104 and nozzles 11
Reference numerals 2 each configure each channel of the inkjet head 10.

Next, the driving means of the ink jet recording apparatus will be described. As shown in the block diagram of FIG. 4, this driving means includes a head driving signal generating circuit 27 for supplying a driving signal to the metal electrode 108 of the individual ink chamber 104 of each channel based on print data supplied from a host computer such as a personal computer. And a clock 21 and a pulse width setting circuit 2
2 and a shift register 24. The head drive signal generation circuit 27 is formed by combining a known CPU, ROM, RAM and the like. The clock 21 is shown in FIG.
A reference signal as shown in FIG. The pulse width setting circuit 22 generates a signal having a time width AL as shown in FIG. 5B by being triggered by the reference signal of the clock 21. The shift register 24 has, for example, three terminals A, B, and C corresponding to the number of divisions of the channel drive described later.
The ON terminal is sequentially changed as shown in FIG.

Further, AND gates 25A, 25B, and 25C are provided for obtaining the logical product of the output of the clock 21, the output of the pulse width setting circuit 22, and the output of the head drive circuit 27, and their output signals are supplied to an amplifier 26A. , 26B, 2
The signal is amplified by 6C and applied to each metal electrode 108.

Here, the same number of AND gates and amplifiers are provided in one-to-one correspondence with the channels of the ink jet head 10, and are divided into, for example, three groups in accordance with the number of divisions of the channel drive described later. That is, the sending ports 181 to 188 and 191 to 198 of the channels in FIG.
Are similarly allocated to, for example, three groups (A, B, C) in order from one end of the column.

As a result, the outlets 181, 184, 18
7, 192, 195, 198 (hereinafter referred to as “Group A”), the metal electrodes 108 of each individual ink chamber 104
Similarly, an AND gate 25A and an amplifier 26A are connected. Outlets 183, 186, 191, 19
The same AND gate 25B and amplifier 26B are connected to the metal electrodes 108 of the individual ink chambers 104 corresponding to 4,197 (hereinafter referred to as "group B"), respectively.
Also, the outlets 182, 185, 188, 193, 196
(Hereinafter referred to as “group C”).
And the same number of AND gates 2
5C and an amplifier 26C are connected respectively. FIG.
Shows only one set of AND gates and amplifiers on behalf of each group.

Next, the operation of the ink jet recording apparatus will be described.

The basic operation of the ink jet recording apparatus is as follows.
By driving and controlling the carriage 9 and the inkjet head 10 in accordance with a command signal from a personal computer or the like while printing paper S is conveyed by the platen roller 62, characters, symbols, figures, and the like are printed and printed on the printing paper S. is there. When printing is performed, the printing paper S supplied from a paper supply cassette or the like is sent by the platen roller 62 to a position where a line to be printed faces the inkjet head 10 and is stopped there. Then, the CR motor 6 is moved within a range where the carriage 9 faces the printing paper S on the platen roller 6.
8, the ink jet head 10 is driven at a predetermined printing speed, during which the ink jet head 10 ejects ink in accordance with a command signal to perform printing.

The ejection of ink by the ink jet head 10 is performed as follows. When recording data is supplied from a personal computer or the like, the head driving circuit 27 (FIG. 4)
In accordance with the data, a voltage signal is applied to the metal electrode 108 (see FIG. 2) of the partition portion 106 defining the individual ink chamber 104 corresponding to the nozzle 112 to be ejected, via an AND gate or an amplifier. Therefore, the partition 106 is piezoelectrically deformed, and pressure is applied to the ink in the individual ink chamber 104. Due to this pressure, the nozzle 11
From 2, the ink in the individual ink chamber 104 is ejected and adheres to the printing paper S to perform print recording. After the ejection, the ink is supplied to the individual ink chamber 104 from the ink tank 12 through one of the common ink chambers 18 and 19 of the ink manifold 14.

Here, in this ink jet recording apparatus,
The timing of applying the voltage signal to the individual ink chamber 104 of each channel is divided into a plurality of, for example, three as shown in FIG. That is, the clock 21 (see FIG. 4) is
Is generated, the reference signal is supplied to the pulse width setting circuit 22 (see FIG. 4) and the shift register 24 (see FIG. 4).
See). For this reason, the width setting circuit 22 is triggered by each reference signal to generate a signal having a time width AL shown in FIG. 5B, and the AND gates 25A, 25B, 25
Supply to C. On the other hand, the shift register 24 sequentially turns on the three terminals A, B, and C according to the reference signal as shown in FIG.
5A, 25B and 25C.

The AND gate 25A receives the signal (FIG. 5 (b)) from the width setting circuit 22 and the A of the shift register 24.
The group A receives three inputs of a terminal signal (A in FIG. 5 (c)) and a drive signal (A in FIG. 5 (d)) from the head drive circuit 27, and obtains a logical product of the three signals via the amplifier 26A. Is supplied to the metal electrode 108 of the channel belonging to.
Here, each channel belonging to the group A is a head drive circuit 2
7 are driven by respective drive signals input to the corresponding AND gates 25A.

The AND gate 25B is connected to the width setting circuit 2
5 (FIG. 5 (b)), the B terminal signal of the shift register 24 (FIG. 5 (c)), and the driving signal from the head drive circuit 27 (FIG. 5 (d)). One input,
A signal is supplied to the metal electrode 108 of the channel belonging to the group B via the amplifier 26B based on these logical product. Here, each channel belonging to the group B is driven by a respective drive signal input from the head drive circuit 27 to each corresponding AND gate 25B.

Similarly, the AND gate 25C receives the signal of the width setting circuit 22 (FIG. 5B) and the C of the shift register 24.
The three groups of terminal signals (C in FIG. 5C) and a drive signal (C in FIG. 5D) from the head drive circuit 27 are received, and a logical product of these signals is input to the C group via the amplifier 26C. Is supplied to the metal electrode 108 of the channel belonging to.
Here, the channels belonging to the group C are the head drive circuit 27
Are driven by the respective drive signals input to the corresponding AND gates 25C.

Therefore, if the drive signal from the head drive circuit 27 to a certain channel belonging to each of the groups A, B, and C is, for example, as shown in FIG.
The output signals of A, 25B and 25C are as shown in FIG. 5 (e), and the corresponding channel is driven according to this. For this reason, channels belonging to different groups are not driven at the same timing.

This will be described with reference to the channel arrangement shown in FIG.
That is, channels belonging to the same A, B, and C groups,
The closest channels connected to the same common ink chambers 18, 19 are, for example, 181 and 184, and between them, 191, 182, 192, 183, 193
There are two channels. The five channels 181 and 184 are groups of drive timings A, B,
At least one of the common ink chambers 18 and 19 connected to C is different. The same applies to other channels.

Therefore, in this ink jet recording apparatus, the closest channel affected by crosstalk when each channel is driven is the channel that is five channels away. In the graph of FIG. 8, since “both sides 6” does not show an increase in speed with respect to “both sides 5”, it is understood that the influence of the crosstalk between the channels can be ignored.

The number "5" is obtained by subtracting 1 from the least common multiple "6" of the number "2" of the common ink chambers and the number "3" of the drive signal timing. If these two numbers are equal or one is an integral multiple of the other, it is not possible to take a sufficient interval between the channels having the same common ink chamber and the same drive timing unless the numbers themselves are increased. . On the other hand, if any combination is a number other than an integer multiple of the other number, the channel of the least common multiple of both can be interposed, and
Even if the number of both is not so large, a sufficient interval can be obtained. This effect is most pronounced when the numbers are relatively prime. For this reason, in the present embodiment, the number of common ink chambers is set to “2”, and the number of drive signal timings is set to “3”.

In this ink jet recording apparatus,
When the ratio AL / TL of the ON time AL of the drive signal to the drive cycle (denoted by TL in FIG. 5) is used under a relatively large condition, as shown in FIG. The driving time may partially overlap between the channels to which the channels belong. For this reason, the driving time may overlap between adjacent channels such as 181 and 191 in FIG. 3, but these adjacent channels are always connected to different common ink chambers 18 and 19, , No crosstalk occurs between them.

As described in detail above, in this ink jet recording apparatus, two common ink chambers 18 and 19 are provided in the ink manifold 14 connecting the ink tank 12 and the ink jet head 10, and the individual ink chambers 104 of the adjacent channels are formed. Be sure to use separate common ink chambers 18, 19
, And the driving signal application timing to the metal electrode 108 is divided into three groups A, B, and C, and each channel belongs to these groups in the order of A, B, C,. Therefore, there are five other channels between the channels that are supplied with ink from the same common ink chamber and are driven at the same timing, and that even when these are driven together, The speed does not increase due to crosstalk. That is, since the number of common ink chambers and the number of drive timings are mutually primed, it is necessary to provide a sufficiently large interval between channels that can receive crosstalk, despite that neither number is so large. It was done.

Even if the drive times of different groups partially overlap due to a large ratio of the on-time to the drive cycle, the individual ink chambers 104 of adjacent channels
Are always connected to separate common ink chambers 18, 19, so that there is no crosstalk between them.

Thus, there is provided an ink jet recording apparatus capable of obtaining a high quality print recording result by almost completely eliminating the speed fluctuation of the ejected ink due to the influence of crosstalk between the channels and the ink leakage from the non-driving channels. Have been.

The present invention is not limited to this embodiment, and it goes without saying that various improvements and modifications can be made without departing from the spirit of the present invention. For example, in this embodiment, the number of common ink chambers is set to 2 and the number of drive timings is set to 3. However, the present invention is not limited to this, and other numbers may be used unless one is an integral multiple of the other.

[0045]

According as the present invention has been described in the foregoing, and it both a number group of the pressing means constituting the individual number and the driving means of the common ink chamber is a number other than the other integral multiple, more Since it is preferably disjoint, a sufficient number of other channels are provided between channels driven at the same timing without excessively increasing the number of drives, and furthermore, crosstalk between adjacent channels is reduced. It is possible to provide an excellent ink jet recording apparatus which can completely eliminate and obtain a high quality recording result.
it can.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view illustrating the configuration of an ink jet recording apparatus.

FIG. 2 is an exploded perspective view illustrating the structure of the inkjet head.

FIG. 3 is a diagram illustrating a configuration of an ink manifold of the inkjet recording apparatus according to the present invention.

FIG. 4 is a block diagram illustrating a control system of the inkjet recording apparatus.

FIG. 5 is a timing chart showing various control signals in the ink jet recording apparatus.

FIG. 6 is a timing chart showing a state in which drive times are partially overlapped between different drive timing groups.

FIG. 7 is a timing chart showing an example of a drive signal in a conventional ink jet recording apparatus.

FIG. 8 is a graph illustrating the effect of crosstalk from a nearby channel.

FIG. 9 is a graph illustrating the effect of a partial overlap of drive times between adjacent channels.

[Explanation of symbols]

 18, 19 Common ink chamber 24 Shift register 27 Head drive circuit 104 Individual ink chamber 106 Partition wall 108 Metal electrode 112 Nozzle

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/175

Claims (3)

(57) [Claims] 1. An ink jet recording apparatus for recording by ejecting ink from a plurality of nozzles onto a recording medium, wherein ink is supplied from two or more separated common ink chambers and adjacent common ink chambers different from each other.
A plurality of individual ink chambers arranged in substantially a row so as to receive, and each provided with the nozzle ; and a pressurizing means provided in each of the individual ink chambers and pressurizing ink in the individual ink chamber, Addition of individual ink chambers adjacent in the column direction of the individual ink chambers
Driving means for dividing the pressure means into three or more groups and applying drive signals at different timings for each group so that the pressure means do not belong to the same group; the number of and the number group of said pressurizing means, both Ri number der other than times other integer, addition of one group圧手
One common ink in the individual ink chamber corresponding to the column
Between the two separate ink chambers connected to the
An ink jet recording apparatus, wherein an individual ink chamber connected to the ink chamber is located . 2. An ink jet recording apparatus according to claim 1, wherein the number of said common ink chambers and the number of said pressurizing means are mutually prime. 3. The ink-jet recording apparatus according to claim 1, wherein said pressurizing unit is configured to output said individual ink.
Characterized in that the wall of the room is deformed.
Liquid jet recording device.