JP2011218748A - Liquid ejecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejecting apparatus which can prevent failure caused by variations in the distance between a plurality of head units and between recording heads.SOLUTION: In adjacent head units 5U, each head unit 5U is mounted to a second head mounting member 15 so that a relative position in a first direction of nozzles 17 in nozzle groups adjacent to each other in the first direction is deviated only an offset amount δ1 corresponding to a relative displacement amount in the first direction of each head unit 5U to a normal formation pitch.

Description

  The present invention relates to a liquid ejecting apparatus including, for example, an ink jet recording head, and more particularly to a liquid ejecting apparatus including a plurality of liquid ejecting heads.

The liquid ejecting apparatus includes a liquid ejecting head and ejects various liquids from the liquid ejecting head. As a typical example of this liquid ejecting apparatus, for example, an ink jet recording head (hereinafter simply referred to as a recording head) is provided, and liquid ink is dropped from the recording head onto recording paper or the like as an ejecting target. And an image recording apparatus such as an ink jet recording apparatus (hereinafter simply referred to as a printer) that performs recording by forming dots by jetting and landing.
In recent years, this liquid ejecting apparatus is applied not only to an image recording apparatus but also to various manufacturing apparatuses such as a display manufacturing apparatus.

The printer includes a recording head (so-called serial head) that is shorter than the width of a recording medium (liquid ejection target) such as paper or a resin film, a head moving mechanism that reciprocates the recording head in the head scanning direction, and a recording medium. Is provided in a direction perpendicular to the head scanning direction to carry out sub-scanning and the like, and by sequentially repeating ink ejection and recording medium conveyance (sub-scanning) in the main scanning of the recording head to the recording medium The image is recorded.
However, this method has a limitation in the scanning speed of the recording head. For example, when an image is recorded on the entire surface of a relatively large size recording medium, there is a problem that much time is required. .

For this reason, in recent years, a plurality of recording heads each having a nozzle group in which a plurality of nozzles are arranged in the first direction are attached to the carriage in the first direction, and the first of the nozzle groups formed by these recording head groups. The head unit whose total length in the direction corresponds to the maximum recording width of the recording medium is relative to the second direction that intersects (ideally orthogonal) the first direction without moving the recording unit in the first direction. There has been proposed a configuration in which ink is ejected while moving in a moving manner (Patent Document 1).
According to this configuration, the recording time can be shortened compared to a configuration using a serial head.

JP 2009-137091 A

However, in a printer that performs recording using a plurality of recording heads as described above, for example, each recording head or carriage constituting the head unit is thermally expanded due to a change in environmental temperature or heat generation of the recording head itself. For this reason, there is a possibility that the interval between the recording heads fixed to the carriage may fluctuate.
For example, if the temperature inside the printer rises higher than the environmental temperature in the process of attaching each recording head to the carriage, the interval between the adjacent recording heads A and B becomes wider than the interval at the time of attachment. As shown in the schematic diagram of FIG. 8, the nozzles of each recording head also move relatively from the position indicated by the broken line to the position indicated by the solid line.
As a result, the ink deviates from the original landing position on the recording medium, resulting in dot density, which appears as a streak in the image recorded on the recording medium, which may reduce the recording quality. In particular, the above-described problem occurs when an image is printed by each recording head using the same color ink.

  A similar problem also occurs in a printer in which a plurality of head units each having a plurality of recording heads mounted in the first direction with respect to the head mounting member are further arranged in the first direction with respect to the carriage. In this printer, the distance between the head units in the carriage may fluctuate, and the distance between the recording heads in the head mounting member may fluctuate.

  The present invention has been made in view of such circumstances, and an object of the present invention is to prevent problems caused by fluctuations in the interval between a plurality of head units and, further, fluctuations in the interval between recording heads. It is an object of the present invention to provide a possible liquid ejecting apparatus.

The liquid ejecting apparatus according to the present invention employs the following means in order to solve the above problems.
In the liquid ejecting apparatus according to the invention, the liquid ejecting head having a nozzle group in which a plurality of nozzles ejecting liquid to a liquid ejecting target are arranged in a first direction at a constant formation pitch is provided on the first head mounting member. A plurality of head units arranged along the first direction are attached to the second head attachment member along the first direction, and moved relative to the liquid ejection target in the second direction intersecting the first direction. A liquid ejecting apparatus including a liquid ejecting head unit that ejects liquid from the nozzle while the nozzles of the nozzle group corresponding to the same type of liquid adjacent to each other in the first direction in adjacent head units. Off corresponding to the relative displacement amount of the head units in the first direction with respect to the normal formation pitch of each nozzle constituting the same nozzle group in the relative position in one direction. Tsu preparative amounts only shifted so that each head unit is characterized in that is attached to the second head mounting member.

The amount of displacement is from the environmental temperature when the operation of attaching the head unit to the second head attachment member is performed in the manufacturing process of the liquid ejecting head to the temperature inside the apparatus (specified temperature) assumed in the liquid ejecting operation. This is the relative displacement in the first direction between the head units due to thermal expansion that occurs when the change occurs.
The offset amount is a value determined based on the displacement amount, and may be a value equal to the displacement amount, or a value that is slightly different from the displacement amount in consideration of an error in the displacement amount, etc. You may do it.

  According to the above configuration, at the time of the liquid ejecting operation, the nozzles adjacent to each other in the first direction between the head units, for example, due to thermal expansion are aligned at a regular formation pitch in the first direction, and the dots land on the liquid ejecting target. The intervals can also be made constant. Thereby, the density of dots can be reduced, and for example, streaks can be prevented from occurring in an image or the like formed on the liquid ejection target.

  Further, in each of the head units, the relative positions in the first direction of the nozzle groups of the nozzle groups corresponding to the same type of liquid adjacent in the first direction in the adjacent liquid ejecting heads constitute the same nozzle group. Each liquid ejecting head is attached to the first head mounting member so as to be shifted by an offset amount corresponding to the relative displacement amount of the liquid ejecting heads in the first direction with respect to the normal formation pitch of each nozzle. It is characterized by that.

The displacement amount is from the environmental temperature when the operation of attaching the liquid ejecting head to the first head attaching member in the head unit manufacturing process is performed to the temperature inside the apparatus (specified temperature) assumed in the liquid ejecting operation. This is a relative displacement amount in the first direction between the liquid jet heads due to thermal expansion that occurs when the change occurs.
The offset amount is a value determined based on the displacement amount, and may be a value equal to the displacement amount, or a value that is slightly different from the displacement amount in consideration of an error in the displacement amount, etc. You may do it.

  According to the above configuration, during the liquid ejecting operation, the nozzles adjacent in the first direction between the liquid ejecting heads are aligned at a regular formation pitch in the first direction, for example, due to thermal expansion, and land on the liquid ejecting target. The dot spacing can also be made uniform. Thereby, the density of dots can be reduced, and for example, streaks can be prevented from occurring in an image or the like formed on the liquid ejection target.

FIG. 2 is a diagram illustrating a schematic configuration of a printer according to an embodiment of the invention. It is the enlarged plan view which looked at the head part from the nozzle formation surface side. It is the top view which expanded and showed the area | region A in FIG. It is the top view which expanded and showed the area | region B in FIG. It is the top view which expanded and showed the area | region C in FIG. FIG. 6 is a duplex diagram illustrating a state in which a part of a ruled line is formed using nozzles at portions where nozzle row end portions between adjacent print heads overlap each other. FIG. 6 is a duplex diagram illustrating a state in which a part of a ruled line is formed using nozzles at portions where nozzle row end portions between adjacent print heads overlap each other. FIG. 9 is a duplex diagram for explaining a state in which a part of a ruled line is formed using nozzles at portions where nozzle row end portions between adjacent print heads overlap in a conventional configuration.

The best mode for carrying out the present invention will be described below with reference to the drawings.
It should be noted that in the embodiments described below, there are various limitations as preferred specific examples of the present invention, or the scope of the present invention is limited to these unless otherwise specified in the following description. However, the present invention is not limited to this embodiment.

In the present embodiment, an image recording apparatus which is one form of a liquid ejecting apparatus, and more specifically, an ink jet printer (hereinafter referred to as a printer) including a plurality of ink jet recording heads (hereinafter simply referred to as recording heads) as a liquid ejecting head. Will be described as an example.
FIG. 1 is a diagram illustrating a schematic configuration of a printer 1 according to an embodiment of the present invention. Specifically, FIG. 1A is a schematic side view of the printer 1, FIG. 1B is a schematic plan view of the printer 1, and FIG. 1C is a schematic view of the head unit 5 viewed from the nozzle forming surface side. FIG.

The printer 1 (liquid ejecting apparatus) of the present embodiment is a unit image that is used after being cut out on a strip-shaped printing tape 2 that is a kind of recording medium (a liquid ejecting target), for example, a surface of a packaging such as food or a bottle The sticker-like label affixed to is printed by an inkjet method.
The printing tape 2 is roll paper (continuous paper) with release paper.
Then, the printer 1 continuously prints an image as a label in a direction in which the printing tape 2 is continuous.

The printer 1 in this embodiment is schematically configured by a control unit (printer controller) (not shown), a transport unit 3, a drive unit 4, and a head unit 5.
The transport unit removes the print tape 2 in the direction in which the print tape 2 continues (second direction; hereinafter referred to as the transport direction) from the supply roll 7 arranged on the upstream side to the take-up roll 8 side on the downstream side. Sent (direction indicated by black arrow in FIG. 1).
The transport unit 3 includes a pair of upper and lower feed rollers 9a and 9b, a pair of upper and lower feed rollers 10a and 10b, a suction table 11 and the like. The feeding rollers 9a and 9b are rotated by a driving motor (not shown) with the printing tape 2 nipped between each other, and the printing tape 2 is fed from the supply roll 7 and fed to the suction table 11 side which is a printing area.

  The suction table 11 is a member that supports the printing tape 2 from the back surface opposite to the printing surface on which ink is landed during the printing operation. The suction table 11 is provided with a large number of suction ports 13 on the entire upper surface thereof, and the printing tape 2 supplied to the upper surface is sucked through the suction ports 13 from below by a suction mechanism (not shown) during the printing operation. It is comprised so that it may contact | adhere to the upper surface. A platen heater 12 is disposed inside the suction table 11. As will be described later, the platen heater 12 heats the atmosphere inside the printer until the internal temperature of the printer 1 reaches a specific temperature before the printing operation, and promotes drying of images printed on the printing tape 2. For this purpose, the printing tape 2 is heated.

  The delivery rollers 10a and 10b are rotated by a drive motor (not shown) with the print tape 2 nipped between each other, and send the printed print tape 2 from the printing region side to the take-up roll 8 side. The printing tape 2 sent out from the printing area is taken up by the take-up roll 8.

  The drive unit 4 is a moving mechanism for moving the head unit 5 in a second direction (head scanning direction) corresponding to the transport direction of the printing tape 2. The drive unit 4 includes a total of two guide rails 14 extending along the transport direction, one on each side of the suction table 11 in the first direction, and the head unit 5 is provided along the guide rails 14. It can be moved in the head scanning direction.

  The head unit (liquid ejecting head unit) 5 is landed by ejecting ink onto the printing tape 2 disposed on the suction table 11 while being moved in the head scanning direction by the drive unit 4 while being guided by the guide rail 14. By doing so, dots are formed, and an image or the like is printed on the printing tape 2 by the collection of dots.

For example, four head units 5U are attached to the carriage (second head attachment member) 15 on the back surface side (the suction table 11 side) of the head unit 5.
Each head unit 5U is configured by attaching, for example, three or four recording heads (liquid ejecting heads) 16 to a head attaching plate (first head attaching member) 6.
That is, the head unit 5 has a configuration in which, for example, 15 recording heads 16 are attached to the carriage 15 via, for example, four head units 5U.

FIG. 2 is a plan view of the head unit 5 as viewed from the bottom surface side (nozzle formation surface side).
As shown in FIG. 2, each recording head 16 intersects the carriage 15 in the head scanning direction so that the adjacent recording heads 16 are alternately arranged in two stages in the head scanning direction (lateral direction in FIG. 2). Are arranged at regular intervals along the first direction (vertical direction in FIG. 2).

More specifically, a plurality of recording heads 16 (m) to 16 (n) are provided for the head mounting plate 6 (j), and a recording head 16 (m-1) is provided for the head mounting plate 6 (j-1). Etc., the recording head 16 (n + 1) and the like are respectively arranged and fixed with respect to the head mounting plate 6 (j + 1).
In the same head mounting plate 6, the recording heads 16 adjacent to each other are arranged at regular intervals along a first direction intersecting the head scanning direction so that the recording heads 16 are alternately arranged in two stages in the head scanning direction. Has been.

  In addition, each head mounting plate 6 is arranged in a line along the head scanning direction between adjacent head mounting plates 6. The recording head 16 arranged on the most side in the scanning direction on each head mounting plate 6 has two stages in the head scanning direction with respect to the recording head 16 arranged on the most other side in the adjacent head mounting plate 6. It is arranged to become.

For example, the recording head 16 (m) of the head mounting plate 6 (j) partially overlaps the recording head 16 (m-1) of the head mounting plate 6 (j-1) in the first direction. Are arranged on one side of the head scanning direction.
On the other hand, the recording head 16 (n) of the head mounting plate 6 (j) is in the head scanning direction so as to partially overlap the recording head 16 (n + 1) of the head mounting plate 6 (j + 1) in the first direction. It is arranged on the other side.
Then, as described above, as a whole of the head unit 5, all the recording heads 16 are arranged at regular intervals along the first direction so that the adjacent recording heads 16 are alternately arranged in two stages in the head scanning direction. Are arranged side by side.

  The head unit 5 can be ejected over the entire width of the printing tape 2 by one movement in the head scanning direction, that is, the total length of the nozzle group including the nozzles 17 of each recording head is as follows. Each recording head 16 is arranged so as to be larger than the width of the printing tape 2.

The head attachment plate 6 is a plate-like member used for indirectly attaching the plurality of recording heads 16 to the carriage 15 and is formed of the same material as the carriage 15, for example.
And as shown in FIG. 2, it forms in the shape of a double collar, a parallelogram, etc. That is, when the plurality of head mounting plates 6 are arranged in a line along the first direction with respect to the carriage 15, the adjacent head mounting plates 6 do not overlap (interfere) in the thickness direction. The shape is partially overlapping in the direction.
As described above, with respect to each head mounting plate 6, a plurality of recording heads 16 are arranged at regular intervals along the first direction so as to be alternately arranged in two stages in the head scanning direction.

  Each head mounting plate 6 is formed with positioning holes H1 on both ends in the head scanning direction (two in total). The carriage 15 has eight positioning holes H2 corresponding to the head mounting plates 6. Then, each head mounting plate 6 is arranged with respect to the carriage 15 so that the positioning holes H1 and H2 coincide with each other, and the locating pin R is inserted into the positioning holes H1 and H2, thereby the head mounting plate. 6 is positioned and fixed to the carriage 15 with high accuracy.

  The recording head 16 includes a pressure chamber communicating with the nozzle 17 and pressure generating means for causing pressure fluctuations in ink in the pressure chamber (for example, a piezoelectric vibrator, a heating element, etc., neither of which is shown). By applying a drive signal from the control unit to the pressure generating means and driving the pressure generating means, a printing operation (liquid that ejects ink (a kind of liquid in the present invention) from the nozzles 17 and lands on the printing tape 2. (Injection operation).

On the nozzle forming surface 18 of each recording head 16, a plurality of nozzles 17 for ejecting ink are provided in the first direction to form a nozzle row (a type of nozzle group), and a plurality of nozzle rows are provided in the head scanning direction. In this embodiment, four rows are formed.
One nozzle row includes, for example, 360 nozzles 17 (# 1) to 17 (# 360) provided at a pitch corresponding to 360 dpi, that is, at an interval of 70 μm. In each recording head 16, one nozzle row corresponds to each ink type, that is, each ink color.
In the present embodiment, each recording head 16 has a total of four columns corresponding to four colors of ink, yellow ink (Y), magenta ink (M), cyan ink (C), and black ink (K). Nozzle rows are formed side by side in the head scanning direction.

FIG. 3 is an enlarged plan view showing a region A in FIG.
4 is an enlarged plan view showing a region B in FIG.
FIG. 5 is an enlarged plan view showing a region C in FIG.

In FIG. 3, the arrangement relationship of the nozzles of the recording head 16 (m−1) of the head mounting plate 6 (j−1) and the recording head 16 (m) of the head mounting plate 6 (j) will be described as an example. .
In FIG. 4, the arrangement relationship of the nozzles of the recording head 16 (n) of the head mounting plate 6 (j) and the recording head 16 (n + 1) of the head mounting plate 6 (j + 1) will be described as an example.
In FIG. 5, the arrangement relationship of the nozzles of the recording head 16 (n−1) and the recording head 16 (n) of the head mounting plate 6 (j) will be described as an example.

Also, in the combination of other adjacent head mounting plates (recording heads), the arrangement relationship is such that the ends of the nozzle rows overlap as described below.
3 to 5, the vertical direction of the paper surface is the first direction, the upper side of the paper surface is one side of the first direction, and the lower side of the paper surface is the other side of the first direction.

As shown in FIG. 3, the recording heads 16 at both ends of the adjacent head mounting plates 6 are adjacent to each other so that the positions in the first direction of the end portions of the nozzle rows overlap each other.
In the present embodiment, among the adjacent head mounting plates 6 (recording heads 16), in the nozzle row of the recording head 16 (m-1) of the head mounting plate 6 (j-1) on one side in the first direction, The head mounting plate on the other side with respect to the arrangement region in the first direction of the four nozzles 17 (# 357), 17 (# 358), 17 (# 359), and 17 (# 360) located at the other end The four nozzles 17 (# 1), 17 (# 2), 17 (# 3), and 17 (# 4) located at one end in the nozzle row of the recording head 16 (m) of 6 (j) The arrangement areas in the first direction overlap.

  More specifically, the nozzles of the recording head 16 (m) of the head mounting plate 6 (j) with respect to the nozzles 17 (# 357) of the recording head 16 (m-1) of the head mounting plate 6 (j-1). 17 (# 1) is in a correspondence relationship. Similarly, the nozzle 17 (# 2) of the recording head 16 (m-1) corresponds to the nozzle 17 (# 358) of the recording head 16 (m-1), and the nozzle 17 ( The nozzle 17 (# 3) of the recording head 16 (m) corresponds to # 359), and the nozzle 17 of the recording head 16 (m) corresponds to the nozzle 17 (# 360) of the recording head 16 (m-1). (# 4) corresponds.

Further, as shown in FIG. 4, one end of the nozzle row of the recording head 16 (n) of the head mounting plate 6 (j) and the nozzle row of the recording head 16 (n + 1) of the head mounting plate 6 (j + 1). Similarly, in the overlap region with the other side end, four sets of nozzles 17 are in a correspondence relationship.
That is, the nozzle 17 (# 357) of the recording head 16 (n) of the head mounting plate 6 (j) corresponds to the nozzle 17 (# 1) of the recording head 16 (n + 1) of the head mounting plate 6 (j + 1). The nozzle 17 (# 358) of the recording head 16 (n) corresponds to the nozzle 17 (# 2) of the recording head 16 (n + 1) and corresponds to the nozzle 17 (# 3) of the recording head 16 (n + 1). The nozzle 17 (# 359) of the recording head 16 (n) corresponds to the nozzle 17 (# 359) of the recording head 16 (n), and the nozzle 17 (# 360) of the recording head 16 (n) corresponds to the nozzle 17 (# 4) of the recording head 16 (n + 1). ing.

Further, as shown in FIG. 5, even within the same head mounting plate 6 (j), one side end of one nozzle row and the other side end of the other nozzle row are located between adjacent recording heads 16. Similarly, in the overlap region, four sets of nozzles 17 are in a correspondence relationship.
That is, the nozzle 17 (# 357) of the recording head 16 (n-1) corresponds to the nozzle 17 (# 357) of the recording head 16 (n) of the head mounting plate 6 (j), and the recording head 16 ( The nozzle 17 (# 358) of the recording head 16 (n-1) corresponds to the nozzle 17 (# 2) of n), and the recording head 16 corresponds to the nozzle 17 (# 3) of the recording head 16 (n). The nozzle 17 (# 359) of (n-1) corresponds to the nozzle 17 (# 360) of the recording head 16 (n-1) to the nozzle 17 (# 4) of the recording head 16 (n). ing.

3 to 5, for the sake of convenience, the nozzle row (in this embodiment, black ink (K)) located in the nozzle row located on the rightmost side (the most upstream side in the print tape conveyance direction) of the left recording head. Corresponding relationship between the corresponding nozzle row) and the nozzle row (the nozzle row corresponding to yellow ink (Y) in the present embodiment) located on the leftmost side (the most downstream side in the printing tape conveyance direction) of the right recording head. However, in practice, the nozzle rows corresponding to the same type (same color) have the above-described correspondence.
Further, the number of nozzles in the region where the end portions of the nozzle rows overlap between adjacent print heads is not limited to the example. Of course, it is also possible to adopt a configuration in which the ends of the nozzle rows do not overlap.

Here, conventionally, the arrangement pitch in the first direction of the nozzles adjacent in the first direction between the adjacent head mounting plates (recording heads) is constant at the formation pitch P of each nozzle constituting the same nozzle row. (In the configuration in which the nozzles in the nozzle rows overlap between adjacent recording heads, the positions of the centers of the corresponding nozzles in the first direction coincide). That is, each recording head 16 is attached to the carriage 15 via the head attachment plate 6 so that the entire nozzles 17 of the recording head 16 of each head attachment plate 6 are arranged at a specified pitch P in the first direction. .
However, for example, when the temperature inside the printer rises during the printing operation, the carriage 15, the head mounting plate 6 or the recording head 16 thermally expands, so that the adjacent head mounting plate 6 or the recording head 16 in the first direction. In some cases, the relative positions may fluctuate away from each other. As a result, the arrangement pitch of the nozzles 17 is changed from the regular pitch P, so that the dots that land on the printing tape 2 are sparse and dense, and the image quality of the printed image or the like may be reduced.

  On the other hand, in the printer 1 according to the present embodiment, the nozzles 17 adjacent in the first direction between the adjacent head mounting plates 6 (meaning nozzles that are adjacent to each other in a configuration that is not offset. In the example of FIG. 3, each head is set such that the distance between the nozzle 17 (# 357) of the recording head 16 (n) and the nozzle 17 (# 2) of the recording head 16 (n + 1) is offset by δ1 in a direction approaching each other. A mounting plate 6 is disposed on the carriage 15.

  Furthermore, in the printer 1 according to the present embodiment, the nozzles 17 adjacent in the first direction between the adjacent head mounting plates 6 in the same head mounting plate 6 (the nozzles that are adjacent to each other in a non-offset configuration). For example, in the example of Fig. 5, δ2 is set so that the distance between the nozzle 17 (# 2) of the recording head 16 (n-1) and the nozzle 17 (# 357) of the recording head 16 (n) approaches each other. Each recording head 16 is disposed on the head mounting plate 6 so as to be offset by a distance.

The offset amounts δ1 and δ2 are such that, for example, the adjacent head mounting plates 6 (recording heads 16) are relatively displaced in the first direction due to thermal expansion of the carriage 15, the head mounting plate 6 or the recording head 16 during the printing operation. It is determined based on the amount to be. That is, the relative position in the first direction of the nozzles adjacent in the first direction between the adjacent head mounting plates (recording heads) is the normal formation pitch of each nozzle constituting the same nozzle row (70 μm in this embodiment). On the other hand, the head mounting plates or the recording heads are shifted by offset amounts δ1 and δ2 corresponding to the relative displacement amounts in the first direction due to thermal expansion during the printing operation.
Therefore, the arrangement pitch P ′ in the first direction between the nozzles adjacent in the first direction between the adjacent head mounting plates (recording heads) is represented by P−δ1 or P−δ2.

  For example, the displacement amount between the recording heads is the environment when the operation of attaching each recording head 16 to the head mounting plate 6 and further mounting the head mounting plate 6 to the carriage 15 in the manufacturing process of the head unit 5 is performed. Relative displacements between the head mounting plates 6 and between the recording heads due to thermal expansion caused by a change of ΔT ° C. from a temperature (for example, 23 ° C.) to a temperature (specified temperature) assumed in the printing operation inside the printer 1. It is.

For example, the overall length of the carriage 15 in the first direction is L, the arrangement pitch of the head mounting plates 6 is HP, the linear expansion coefficient of the carriage 15 is α (1 / ° C.), and the linear expansion coefficient of the head mounting plate 6 is β (1 / ° C)
Displacement amount D1 = (α × L × ΔT) + (β × HP × ΔT)

Similarly, for example, the total length in the first direction of the head mounting plate 6 is M, the arrangement pitch of the recording heads 16 is HQ, the linear expansion coefficient of the head mounting plate 6 is β (1 / ° C.), and the linear expansion of the recording head 16 is performed. If the coefficient is γ (1 / ° C),
Displacement amount D2 = (β × M × ΔT) + (γ × HQ × ΔT)

The values of the offset amounts δ1 and δ2 are determined in consideration of the displacement amounts D1 and D2.
For example, the values of δ1 and δ2 may be equal to the relative displacement amounts D1 and D2 in the first direction between the head mounting plates and the recording heads due to thermal expansion during the printing operation (δ1 = D1, δ2 = D2), and values that slightly vary from the displacement amount in consideration of displacement errors and displacement between the heads due to other factors may be adopted (δ1 = D1 + α, δ2 = D2 + β).
In the present embodiment, δ1 = D1 and δ2 = D2 are employed.

In order to shift the arrangement pitch between the adjacent head mounting plates 6 by the offset amount δ1, the arrangement pitch HP of the eight (four pairs) positioning holes H2 formed in the carriage 15 is not a constant pitch but a constant. The pitch is shifted stepwise from the arrangement pitch HP by an offset amount δ1. That is, assuming that the arrangement pitch between the head mounting plates 6 is HP, the arrangement pitches in the first direction of the eight (four pairs) positioning holes H2 are HP, HP-δ1, and HP-2 × δ1.
Thus, each head mounting plate 6 is positioned and fixed to the carriage 15 in a state where the arrangement pitch between the head mounting plates 6 is reliably shifted by the offset amount δ1.
Similarly, a method for positioning and fixing the recording head 16 with respect to the head mounting plate 6 is also performed using a positioning hole (not shown) and a locate pin.

Next, the operation of the printer 1 having the above configuration will be described.
The head unit 5 before starting printing is waiting at the home position. In this embodiment, the temperature inside the printer 1 is a specified temperature (the head mounting plates 6 adjacent to each other due to thermal expansion are relatively δ1 in the first direction, and the recording heads 16 are relatively δ2 in the first direction. Is heated by the platen heater 12 until the temperature is displaced.
As a result, the carriage 15, the head mounting plate 6 and the recording head 16 are thermally expanded, and the arrangement pitch between the head mounting plates and between the recording heads can be made equal to the regular pitch P at the earliest possible stage. it can.
Therefore, it is possible to start the printing operation more quickly.

  When the printing operation is started, the head unit 5 is scanned by the drive unit 4 along the guide rail 14 from the downstream side in the transport direction of the printing tape 2 to the upstream side. By this scanning, for example, a ruled line composed of dot rows arranged in a first direction with a predetermined color is printed, and this ruled line is continuously formed in the head scanning direction (second direction), whereby a predetermined tape on the printing tape 2 is formed. A case where the range is filled will be described.

FIG. 6 is a schematic diagram for explaining a state in which a part of the ruled line is printed by the nozzles 17 where the nozzle row end portions corresponding to the black ink (K) between the adjacent recording heads overlap each other.
As shown in FIG. 6, when printing a part of the ruled line in the overlapping region, first, even-numbered nozzles 17 (in this example, 16 (m)) located in the head scanning direction ahead ( In this example, ink is ejected from the nozzle 17 (# 2) and nozzle 17 (# 4) to form dots on the printing tape 2.

Next, when the head unit 5 and the print tape 2 are relatively moved by a distance in the second direction between the nozzle rows, a recording head 16 (in this example, 16 (m− Ink is ejected from the odd-numbered nozzles 17 (# 357) and nozzles 17 (# 359)) of 1)) to form dots on the printing tape 2.
In this way, the dots formed on the printing tape 2 by ejecting ink from the adjacent recording heads are arranged along the first direction. A ruled line extending in the first direction is printed by these dot groups.

Here, in the printer 1 according to the present embodiment, the relative position in the first direction of the nozzles adjacent in the first direction in the adjacent head mounting plates 6 is the normal formation pitch of each nozzle constituting the same nozzle row. It is shifted from P by an offset amount δ1 corresponding to the relative displacement amount of the head mounting plates 6 in the first direction due to thermal expansion or the like during the printing operation.
Furthermore, the relative positions in the first direction of the nozzles adjacent in the first direction in the recording heads 16 adjacent in the same head mounting plate 6 are relative to the normal formation pitch P of each nozzle constituting the same nozzle row. The recording heads 16 are shifted by an offset amount δ2 corresponding to the relative displacement amount in the first direction between the recording heads 16 due to thermal expansion during the printing operation.

Therefore, during the printing operation, the nozzles adjacent in the first direction are arranged at the regular pitch P between the head mounting plates 6 and between the recording heads 16 due to the thermal expansion, and the interval between the dots that land on the printing tape 2. Can be evenly aligned.
Thereby, the density of dots can be reduced, and streaks can be prevented from occurring in a printed image or the like.

  It should be noted that ink is ejected from the odd-numbered nozzles 17 (in this example, the nozzles 17 (# 1) and 17 (# 3)) of the recording head 16 positioned further in the head scanning direction to form dots on the printing tape 2. After the formation, ink is ejected from the even-numbered nozzles 17 (in this example, the nozzles 17 (# 358) and 17 (# 360)) of the recording head 16 located rearward in the head scanning direction onto the printing tape 2. In some cases, dots are formed.

In the printer 1 according to the above-described embodiment, an example has been described in which the arrangement pitch in the first direction between the adjacent head mounting plates 6 is shifted so as to decrease stepwise by the offset amount δ1 with respect to the normal arrangement pitch HP. However, it is not limited to this.
Conversely, the arrangement pitch in the first direction between the adjacent head mounting plates 6 may be shifted from the normal arrangement pitch HP so as to increase step by step by an offset amount δ1.
Alternatively, an arrangement pitch deviation amount in the first direction generated between the head mounting plates 6 may be measured in advance by an experiment or the like, and an increase / decrease in the offset amount may be mixed according to the deviation amount. That is, since there is a certain tendency in the arrangement pitch deviation amount in the first direction generated between the head mounting plates 6, it is possible to obtain an appropriate arrangement by grasping the tendency of the deviation quantity to occur. It is.

Similarly, an example has been described in which the arrangement pitch in the first direction in the adjacent recording heads 16 in the same head mounting plate 6 is shifted from the regular arrangement pitch HQ so as to decrease step by step by an offset amount δ2. However, it is not limited to this.
Conversely, the arrangement pitch in the first direction between the adjacent recording heads 16 may be shifted from the normal arrangement pitch HQ so as to increase step by step by an offset amount δ2.
Alternatively, an arrangement pitch deviation amount in the first direction generated between the recording heads 16 in the same head mounting plate 6 is measured in advance by an experiment or the like, and an increase / decrease in the offset amount is mixed according to the deviation amount. You may do it. That is, since there is a certain tendency in the arrangement pitch deviation amount in the first direction generated between the recording heads 16, it is possible to obtain a suitable arrangement by grasping the tendency of the deviation quantity to occur. .

For example, when the head unit 5 is scanned along the guide rail 14, the posture of the head unit 5 may meander (rotate in the horizontal direction). That is, the head unit 5 is not always perpendicular to the guide rail 14 (scanning direction), but is seen to move while swinging with an amplitude (angle) of about 1 degree (deg), for example.
In such a case, the head unit 5 is arranged so as to intersect with the guide rail 14 so as to be slightly inclined (for example, about 89 degrees). As a result, the head unit 5 moves while swinging, so that the head unit 5 does not always intersect the guide rail 14 (scanning direction) at an angle of 90 degrees or more. That is, as shown in FIG. 7, the head unit 5 is arranged so as to always intersect at an angle of 88 to 90 degrees with respect to the scanning direction (left and right direction on the paper surface).
This state is substantially the same as the state shown in FIG. 6, that is, the state in which the relative displacement in the first direction between the head mounting plates 6 (recording heads 16) is generated due to thermal expansion or the like.
Therefore, the inclination of the head unit 5 with respect to the guide rail 14 is corrected by adjusting the offset amounts δ1 and δ2 to be reduced stepwise in accordance with the inclination of the head unit 5 with respect to the guide rail 14 (scanning direction). It becomes possible. That is, between the head mounting plates 6 and between the recording heads 16, the nozzles adjacent in the first direction are arranged at the regular pitch P, and the interval between the dots that land on the printing tape 2 can be made uniform.
Thereby, the density of dots can be reduced, and streaks can be prevented from occurring in a printed image or the like.

The arrangement layout of the recording heads 16 and the number of the recording heads 16 are not limited to those exemplified in the above embodiments, and any configuration can be adopted.
In the above embodiment, the configuration in which the atmosphere inside the printer is heated by the platen heater 12 until the specified temperature is reached is exemplified, but the present invention is not limited to this.
A configuration in which the printing operation is waited until the temperature inside the printer reaches a specified temperature without using the platen heater 12 may be employed.

In the above-described embodiment, the ink jet printer has been described as an example of the liquid ejecting apparatus. However, the liquid ejecting apparatus is not limited to the ink jet printer, and may be an apparatus such as a copying machine or a facsimile.
In the above-described embodiment, the roll-shaped printing tape 2 has been described as an example of the recording medium. However, a cut sheet or a film material may be used.

  In the above-described embodiment, the liquid ejecting apparatus that ejects a liquid such as ink has been described as an example of the liquid ejecting apparatus. However, the liquid ejecting apparatus ejects or discharges liquid other than ink. Can be applied. The liquid that can be ejected by the liquid ejecting apparatus includes a liquid material in which particles of the functional material are dispersed or dissolved, and a gel-like fluid.

In the above-described embodiment, as the liquid ejected from the liquid ejecting apparatus, not only ink but also a liquid corresponding to a specific application can be applied. By providing the liquid ejecting apparatus with an ejecting head capable of ejecting a liquid corresponding to the specific application, ejecting the liquid corresponding to the specific application from the ejecting head, and attaching the liquid to a predetermined object, A given device can be manufactured.
For example, a liquid ejecting apparatus disperses (dissolves) a material such as an electrode material and a color material used in manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display (FED) in a predetermined dispersion medium (solvent). It is applicable to a liquid ejecting apparatus that ejects a liquid (liquid material).

In addition, the fluid ejecting apparatus may be a liquid ejecting apparatus that ejects a bio-organic matter used for biochip manufacturing, or a liquid ejecting apparatus that ejects a liquid that is used as a precision pipette as a sample.
In addition, transparent resin liquids such as UV curable resin to form liquid injection devices that pinpoint lubricant oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. May be a liquid ejecting apparatus that ejects a liquid onto the substrate, a liquid ejecting apparatus that ejects an etching solution such as acid or alkali to etch the substrate, or a fluid ejecting apparatus that ejects gel. The present invention can be applied to any one of these liquid ejecting apparatuses.

  DESCRIPTION OF SYMBOLS 1 ... Printer (liquid ejecting apparatus), 2 ... Printing tape (liquid ejecting object), 5 ... Head part (liquid ejecting head part), 5U ... Head unit, 6 ... Head mounting plate (first head mounting member), 15 ... Carriage (second head mounting member), 16 ... recording head (liquid ejecting head), 17 ... nozzle, P ... formation pitch, δ1, δ2 ... offset amount

Claims (2)

A plurality of liquid ejecting heads having a nozzle group in which a plurality of nozzles that eject liquid to a liquid ejecting target are arranged in a first direction at a constant formation pitch are arranged in a first head mounting member along the first direction. A plurality of the head units are attached to the second head attachment member along the first direction, and the liquid is ejected from the nozzle while relatively moving in the second direction intersecting the first direction with respect to the liquid ejection target. A liquid ejecting apparatus including a liquid ejecting head unit,
The relative positions in the first direction of the nozzle groups of the nozzle groups corresponding to the same-type liquid adjacent in the first direction in the adjacent head units with respect to the normal formation pitch of each nozzle constituting the same nozzle group The liquid ejecting apparatus, wherein each head unit is attached to the second head attachment member so as to be shifted by an offset amount corresponding to a relative displacement amount of the head units in the first direction.   In each of the head units, each nozzle in which the relative positions in the first direction of the nozzle groups of the nozzle groups corresponding to the same type of liquid adjacent in the first direction in the adjacent liquid ejecting heads constitute the same nozzle group. The liquid ejecting heads are attached to the first head mounting member so as to be shifted by an offset amount corresponding to the relative displacement amount of the liquid ejecting heads in the first direction with respect to the regular formation pitch. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus.

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