JP2016182720A - Droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet discharge device which can measure an interval between a medium support section for supporting a medium and a droplet discharge section for discharging droplets to the medium supported by the medium support section with a simple configuration.SOLUTION: A droplet discharge device comprises: a medium support section which is formed with a reflection pattern in which a high reflection part with a high reflectance and a low reflection part with a low reflectance are repeatedly arranged; a droplet discharge section which discharges droplets to a discharge area of a medium supported by the medium support section; a detection section which detects a light amount of reflection light of the light emitted to the medium support section or the medium supported by the medium support section; and a control section which performs an operation so that an interval D between the detection section and the medium support section becomes shorter as a light amount difference ΔLV between the light amount of the reflection light from the low reflection part and the light amount of the reflection light from the high reflection part detected by the detection section is larger.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a droplet discharge device such as a printer.

  2. Description of the Related Art Conventionally, as an example of a droplet discharge device, an ink jet printer that forms characters and images by discharging ink as an example of a droplet onto a medium such as a T-shirt is known.

  In such a printer, a medium support unit that supports the medium, a droplet discharge unit that discharges ink onto the medium, an optical detection unit for detecting whether the medium is supported by the medium support unit, And a carriage that reciprocates in the width direction while supporting the droplet discharge section and the detection section (for example, Patent Document 1).

  In such a printer, as the carriage moves in the width direction, the amount of reflected light when irradiating light toward the medium and the reflected light when irradiating light toward the medium support portion are reduced. Depending on the difference from the light quantity, it is detected whether or not the medium is supported by the medium support part, or the size of the medium supported by the medium support part is detected.

Japanese Patent Laid-Open No. 2007-222304

  By the way, in the printer as described above, when the interval between the droplet discharge unit and the medium support unit (the interval between the detection unit and the medium supported by the medium support unit) becomes wide, along with the ink discharge of the droplet discharge unit. As a result, a lot of ink mist smaller than the ink ejected from the droplet ejecting section is generated, which may contaminate the internal configuration of the printer and the medium. In addition, when the above interval is not an appropriate interval, the ink ejected from the droplet ejection unit supported by the carriage reciprocating in the width direction toward the medium is landed with a deviation from the original landing position. There is a risk of reducing the print quality.

  That is, the interval between the droplet discharge unit and the medium support unit (the interval between the detection unit and the medium supported by the medium support unit) is one of the important printer parameters when printing on the medium. . For this reason, in a printer that cannot detect the interval between the droplet discharge unit and the medium support unit, it is difficult to set the interval between the droplet discharge unit and the medium support unit to an appropriate value.

  This situation is not limited to the printer as described above, and liquid droplet ejection is performed by ejecting liquid droplets from a liquid droplet ejection section disposed on a medium supported by the medium support section at a distance from the medium support section. In the apparatus, it is a common problem.

  The present invention has been made in view of the above circumstances. The purpose is to provide a liquid droplet ejection device capable of measuring the distance between a medium support unit that supports a medium and a liquid droplet ejection unit that ejects liquid droplets onto a medium supported by the medium support unit with a simple configuration. There is to do.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A droplet discharge device that solves the above problems includes a medium support unit that supports a medium, a droplet discharge unit that discharges droplets to a discharge region of the medium supported by the medium support unit, and the medium support unit or Based on the detection result of the detection unit that detects the amount of reflected light of the light irradiated toward the medium supported by the medium support unit, the interval between the detection unit and the medium support unit is calculated. A reflection pattern in which a high-reflectance part having a high reflectance and a low-reflection part having a low reflectance are repeatedly arranged, and the arithmetic part is configured to detect the detection part. As the light amount difference between the light amount of the reflected light from the low reflection portion and the light amount of the reflected light from the high reflection portion detected by (1) increases, the calculation is performed so that the interval becomes narrower.
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In general, when the detection unit detects the amount of reflected light, if the distance between the detection unit and the medium support unit (reflection pattern) is narrow, the amount of reflected light increases, while the interval is wide. Reduces the amount of reflected light. For this reason, it is conceivable to calculate the interval between the detection unit and the medium support unit based on the magnitude of the amount of reflected light that is the detection result of the detection unit.

  Here, depending on the installation environment of the droplet discharge device, when ambient light is incident on the detection unit, the actual light amount (light reception amount) detected by the detection unit is from the high reflection unit and the low reflection unit. The amount of light differs from the amount of reflected light. As a specific example, the amount of light detected when the detection unit sets the high reflection unit as a detection target is the amount of reflected light in the high reflection unit when the detection unit emits light toward the high reflection unit, and The amount of light is the sum of the amount of disturbance light.

  In addition, the amount of light detected when the detection unit targets the low reflection portion is the amount of reflected light at the low reflection portion when the detection portion emits light toward the low reflection portion, and the amount of disturbance light. The amount of light is added to the amount of light. Therefore, for example, the interval is calculated based only on the amount of reflected light from the high reflection unit detected by the detection unit, or the interval is calculated only based on the amount of reflected light from the low reflection unit detected by the detection unit. In such a case, an error may occur in the calculated interval according to the amount of disturbance light.

  Therefore, in the above configuration, the interval is calculated according to the light amount difference that is the difference between the light amount of the reflected light at the high reflection portion detected by the detection portion and the light amount of the reflected light from the low reflection portion. Therefore, the interval can be calculated after subtracting the influence of disturbance light. Therefore, according to this configuration, the detection unit and the medium support unit can be configured with a simple configuration without newly providing a detection unit for measuring the distance to the medium support unit according to the light receiving position of the reflected light in the detection unit. Can be measured. In addition, it is usually possible to measure the interval between the droplet discharge unit and the medium support unit based on the interval between the droplet discharge unit and the detection unit determined by the design and the interval between the detection unit and the medium support unit. it can.

  In the droplet discharge device, the medium support unit moves in a first direction while supporting the medium, and the first support unit supports the droplet discharge unit and the detection unit. It is preferable that the apparatus further includes a carriage that reciprocally moves in a second direction that intersects the direction, and in the reflection pattern, the high reflection portion and the low reflection portion are repeatedly arranged in the second direction.

  According to the above configuration, when the carriage is moved in the second direction, the amount of reflected light from the high reflection portion and the low reflection portion can be detected. That is, it is not necessary to newly provide a separate configuration for detecting the amount of reflected light from the high reflection portion and the low reflection portion, and the amount of reflected light can be easily detected.

  In the liquid droplet ejection apparatus, the medium support portion is recessed at the end in the first direction so as to be away from the carriage in a direction intersecting both the first direction and the second direction. It is preferable that an installed retracting portion is formed, and the reflection pattern is formed in the retracting portion.

  According to the above configuration, when the detection unit detects the amount of reflected light from the reflection pattern, the retraction unit of the medium support unit and the detection unit supported by the carriage overlap in the first direction. In this state, the carriage is moved in the second direction. For this reason, it is possible to cause the detection unit to detect the amount of reflected light with a sufficient space between the detection unit and the medium support unit as compared with the case where the retracting unit is not formed.

In the droplet discharge device, it is preferable that the droplet discharge unit is arranged on the first direction side of the detection unit in the carriage.
According to the above configuration, since the droplet discharge unit is arranged on the first direction side of the detection unit, the detection unit is not overlapped with the medium support unit in the first direction. Can detect the amount of reflected light.

  In the liquid droplet ejection device, the medium support unit is mounted on the mounting table on which the medium is mounted and the mounting table so as to border the discharge area, thereby pressing the medium against the mounting table. It is preferable that the reflection pattern is formed in a region facing the detection unit of the frame.

According to the above configuration, since the medium is pressed against the mounting table by the frame body, the medium can be more reliably supported as compared with the case where the medium is mounted on the mounting table.
The droplet discharge device preferably further includes a control unit that restricts the discharge of the droplets of the droplet discharge unit based on the interval calculated by the calculation unit.

  According to the above configuration, droplets are ejected based on the detection result of the detection unit when the interval between the droplet ejection unit and the medium support unit is an inappropriate interval, for example, when the interval is unreasonably wide. Can limit that.

FIG. (A) is a front view showing a partial configuration of the printing apparatus, (b) is a plan view of a printing unit provided in the printing apparatus. (A)-(c) is an exploded perspective view of the medium support part with which a printing apparatus is provided. FIG. 3 is an enlarged plan view showing one corner (left front corner) of a frame body of a medium support portion. FIG. 2 is a block diagram illustrating an electrical configuration of the printing apparatus. (A) shows a state where the distance between the detection unit and the medium support unit is narrow, and (b) shows a light amount distribution in the width direction in this state. (A) shows a state where the distance between the detection unit and the medium support unit is wide, and (b) shows a light amount distribution in the width direction in this state. A map showing the relationship between light intensity difference and interval. It is a figure explaining the effect | action of a printing apparatus, Comprising: (a) shows the partial plane of a printing apparatus, (b) shows the partial side surface of a printing apparatus. It is a figure explaining the effect | action of a printing apparatus, Comprising: (a) shows typically the cross section of the reflective pattern orthogonal to a conveyance direction, (b) shows the light quantity distribution in the width direction.

  Hereinafter, an embodiment in which a droplet discharge device is embodied in a printing device will be described with reference to the drawings. Note that the printing apparatus of the present embodiment is an ink jet printer that forms characters and images by ejecting ink as an example of droplets onto the surface of a fabric (such as a T-shirt) as an example of a medium.

  As shown in FIGS. 1 and 2, the printing apparatus 10 includes a printing unit 20 that performs printing on a medium M such as a T-shirt, a medium support unit 30 that supports the medium M, and a transport unit that transports the medium support unit 30. 40 and an operation unit 50 for performing various settings of the printing apparatus 10.

  In the following description, the width direction of the printing apparatus 10 is the width direction X (+ X, −X), the front-rear direction of the printing apparatus 10 is the transport direction Y (+ Y, −Y), and the vertical direction of the printing apparatus 10 is the vertical direction. The vertical direction is Z (+ Z, −Z). Here, the width direction X, the transport direction Y, and the vertical direction Z are orthogonal to each other.

  As shown in FIG. 2A, the printing unit 20 includes a droplet discharge unit 21 that discharges droplets (ink), an optical detection unit 22 that includes a light emitting unit 221 and a light receiving unit 222, and droplet discharge. A carriage 23 that supports the unit 21 and the detection unit 22, and a guide shaft 24 that supports the carriage 23 so as to reciprocate in the width direction X are provided.

  The printing unit 20 includes a driving pulley 25 provided at one end in the width direction X, a driven pulley 26 provided at the other end in the width direction X, and a timing belt that is hung on the driving pulley 25 and the driven pulley 26. 27 and a carriage motor 28 for driving the drive pulley 25.

  The droplet discharge unit 21 is formed with a nozzle (not shown) that opens to face the medium support unit 30. As shown in FIG. 2B, the droplet discharge unit 21 is disposed so as to be positioned on the + Y side in the transport direction from the detection unit 22. Then, the printing unit 20 prints on the medium M by causing the droplet discharge unit 21 to discharge droplets to the print area PA (discharge area) of the medium M supported by the medium support unit 30.

  The light emitting unit 221 of the detecting unit 22 irradiates (projects) diffused light toward the medium support unit 30 or the medium M supported by the medium support unit 30 as indicated by a one-dot chain line in FIG. In addition, the light receiving unit 222 of the detection unit 22 receives the reflected light of the diffused light emitted by the light emitting unit 221 as indicated by a two-dot chain line in FIG. 2A, and determines the light amount (the amount of received light) of the reflected light. To detect. That is, the detection unit 22 in the present embodiment is a diffuse reflection type optical sensor that irradiates diffused light toward a detection target and receives the reflected light.

  2A and 2B, the drive pulley 25, the driven pulley 26, the timing belt 27, and the carriage motor 28 are provided on the back side of the carriage 23 (conveying direction -Y side). . The timing belt 27 is connected to the back portion of the carriage 23.

  Thus, when the carriage motor 28 rotates, the timing belt 27 mounted on the drive pulley 25 and the driven pulley 26 rotates, and the carriage 23 connected to the timing belt 27 has a width that is the longitudinal direction of the guide shaft 24. Move in direction X. Here, the carriage 23 moves in the width direction + X or moves in the width direction −X according to the rotation direction of the carriage motor 28. In this respect, in the present embodiment, at least one of the width direction + X and the width direction −X corresponds to an example of a “second direction”.

  As shown in FIGS. 2 and 3A, 3 </ b> B, and 3 </ b> C, the medium support unit 30 is configured so that the medium M is placed thereon and the medium M is pressed against the stage 31. A frame 32 that is mounted on the mounting table 31 and a support table 33 that supports the mounting table 31 from below vertically are provided.

  As shown in FIG. 3C, the mounting table 31 has a substantially rectangular plate shape in which the transport direction Y is the longitudinal direction and the width direction X is the short direction. On the mounting table 31, a convex portion 311 that is slightly smaller than the outer shape of the mounting table 31 in plan view is formed to protrude toward the side opposite to the support table 33 (vertically upward).

  As shown in FIG. 3A, the frame body 32 has substantially the same shape as the mounting table 31 in plan view. The frame 32 is formed with an opening 321 for engaging the convex portion 311 of the mounting table 31 and exposing the print area PA of the medium M when the frame 32 is mounted on the mounting table 31. Thus, the frame body 32 is mounted on the mounting table 31 so as to border the medium M. In the following description, the state in which the medium M is sandwiched between the mounting table 31 and the frame body 32 of the medium support unit 30 is referred to as being supported by the medium support unit 30.

  As shown in FIGS. 3A and 4, the surface 322, which is a region that can face the detection unit 22 supported by the carriage 23, in the frame 32, has a vertical direction at an end on the transport direction + Y side. A retracting portion 323 that is recessed in the direction Z (vertically below) away from the carriage 23 in Z is formed across the width direction X.

  On the other end side (−X side) in the width direction X of the retracting portion 323, a reflection pattern RP is formed in which a high reflection portion RP1 having a high reflectance and a low reflection portion RP2 having a low reflectance are repeatedly arranged in the width direction X. ing. As shown in FIG. 3A, the reflection pattern RP has a shorter length in the width direction X than the frame body 32. FIG. 4 is an enlarged plan view of the left front corner portion of the frame body 32.

  The reflection pattern RP may be formed directly on the frame body 32 (medium support portion 30), or formed by attaching a film on which the reflection pattern RP is formed on the frame body 32 (medium support portion 30). Also good.

  Furthermore, the reflectance of the high reflection part RP1 of the reflection pattern RP is higher than the reflectance of the low reflection part RP2, and the detection unit 22 determines the amount of reflected light in the high reflection part RP1 and the amount of reflected light in the low reflection part RP2. It is sufficient that the high reflection part RP1 and the low reflection part RP2 have a difference in reflectivity to such an extent that they can be discriminated. That is, the reflectance of the high reflection part RP1 does not necessarily have to be larger than 0.5, and the reflectance of the low reflection part RP2 does not necessarily have to be less than 0.5.

  Examples of the high reflection portion RP1 include a white portion colored white and a specular reflection portion that specularly reflects irradiated light. Further, as the low reflection part RP2, a black part colored in black, a diffuse reflection part that diffusely reflects the irradiated light, and an inclination that reflects the irradiated light to a position shifted from the light receiving part 222 of the detection unit 22 An inclined portion having a reflecting surface can be given.

  In the present embodiment, the high-reflection portions RP1 and the low-reflection portions RP2 having the same width in the width direction X are alternately arranged. However, the high-reflection portions RP1 and the low-reflection portions RP2 have regularity. Need only be arranged to repeat. For example, when the low reflection part RP2 is expressed by “0 (zero)” and the high reflection part RP1 is expressed by “1”, the reflection pattern RP of the present embodiment is expressed by “101010...” In the width direction X. However, it may be as follows. That is, the reflection pattern RP may be “001001...” Or “110110.

  As shown in FIGS. 1 and 2A, the transport unit 40 includes a base 41 that supports the medium support unit 30 (support base 33) so as to be movable in the transport direction Y, and the medium support unit 30 with respect to the base 41. A transport motor 42 that moves in the transport direction Y, a lift motor 43 that moves the medium support unit 30 in the vertical direction Z with respect to the base 41, and a case 44 that covers the rear portion of the base 41.

  As shown in FIG. 1, the base 41 is formed so as to protrude forward and rearward from the front and back surfaces of the printing apparatus 10. Here, when the medium support portion 30 is supported at the front portion of the base portion 41, the medium support portion 30 is exposed.

  For this reason, in this case, the user can set the medium M on the medium support unit 30 or remove the medium M from the medium support unit 30. In this regard, as shown in FIG. 1, the position where the medium support portion 30 is supported by the front portion of the base portion 41 is also referred to as a “set position”. At the set position, the position of the medium support unit 30 in the vertical direction Z is appropriately changed so that the user can easily set the medium M. On the other hand, when the medium support portion 30 is supported at the rear portion of the base portion 41, the medium support portion 30 is covered with the case 44.

  As a mechanism for moving the medium support unit 30 (support base 33) in the transport direction Y and the vertical direction Z, the rotational motion of the transport motor 42 and the lifting motor 43 is a straight line of the medium support unit 30 (support base 33). Any mechanism that converts to motion may be used. For example, a mechanism using a pulley and a belt may be used, or a mechanism using a rack and a pinion may be used.

  Then, the transport unit 40 drives the transport motor 42 to move (transport) the medium support unit 30 (support base 33) in the transport direction Y. Here, the direction in which the medium support unit 30 is transported is different depending on the rotation direction of the transport motor 42. In addition, the transport unit 40 drives the lifting motor 43 to move (lift) the medium support unit 30 (support base 33) in the vertical direction Z. Here, the direction in which the medium support unit 30 is moved up and down differs depending on the rotation direction of the lift motor 43.

  When the medium support unit 30 moves in the vertical direction Z, the interval between the droplet discharge unit 21 and the medium support unit 30 and the interval between the detection unit 22 and the medium support unit 30 are changed. That is, the lifting motor 43 corresponds to an example of an “adjustment unit” that adjusts the distance between the droplet discharge unit 21 (detection unit 22) and the medium support unit 30.

  Note that since the printing apparatus 10 of the present embodiment is a so-called serial printer, during the printing of the medium M, the conveyance operation of the medium support unit 30 (medium M) in the conveyance direction −Y and the width direction of the carriage 23 are performed. The movement to + X and -X is performed alternately. In the following description, the transport amount in the transport operation of the medium support unit 30 that is performed alternately with the movement operation of the carriage 23 during printing is also referred to as “unit transport amount”. The unit transport amount is set according to the length of the nozzle row formed in the droplet discharge unit 21.

  In the printing apparatus 10 according to the present embodiment, when printing is started after the medium M is set on the medium support unit 30 at the set position, first, the conveyance direction −Y is set so that the medium support unit 30 is supported by the rear portion of the base 41. Moved to. Thereafter, the printing unit 20 performs printing on the medium M supported by the medium support unit 30 while moving the medium support unit 30 in the transport direction + Y. In this regard, in the present embodiment, the transport direction + Y corresponds to an example of “first direction”.

Next, the electrical configuration of the printing apparatus 10 will be described with reference to FIG.
As shown in FIG. 5, the printing apparatus 10 includes a control unit 60 that comprehensively controls the apparatus. The detection unit 22 is connected to the input side interface of the control unit 60, while the detection unit 22, the droplet discharge unit 21, the carriage motor 28, the transport motor 42, and the lifting motor 43 are connected to the output side interface of the control unit 60. Has been.

  Thus, the control unit 60 controls the driving of the droplet discharge unit 21, the carriage motor 28, the transport motor 42, and the lifting motor 43 based on the detection signal from the detection unit 22, that is, the amount of reflected light from the detection target. To do. Specifically, the control unit 60 allows or restricts the droplet discharge of the droplet discharge unit 21 based on the interval between the detection unit 22 and the medium support unit 30 (reflection pattern RP).

  In the following description, the carriage motor 28 is driven to cause the droplet discharge unit 21 to discharge droplets toward the medium M while moving the carriage 23 in the width direction + X or the width direction −X. It is also called “printing operation (ejection operation)”. In addition, while moving the carriage 23 in the width direction + X or the width direction −X, irradiating light toward the reflection pattern RP or the medium M formed on the frame body 32 and detecting the amount of the reflected light. It is also called “detection operation”.

  Now, like this embodiment, using the detection part 22 which irradiates light toward a detection target and detects the light quantity of the reflected light from the detection target, the space | interval of the detection part 22 and the medium support part 30 is set. As a measuring method, for example, a method of calculating the interval according to the amount of reflected light from the detection target can be considered.

  That is, when the interval between the detection unit 22 and the medium support unit 30 is narrow, most of the light emitted from the detection unit 22 toward the medium support unit 30 is reflected toward the detection unit 22, and thus the detection unit 22. The amount of reflected light detected by is likely to increase. On the other hand, when the interval between the detection unit 22 and the medium support unit 30 is wide, most of the light emitted from the detection unit 22 toward the medium support unit 30 is not reflected toward the detection unit 22. The amount of reflected light detected is likely to decrease.

  Thus, it can be said that the smaller the distance between the detection unit 22 and the medium support unit 30, the greater the amount of reflected light detected by the detection unit 22 when irradiating the medium support unit 30. Therefore, a method is conceivable in which the calculation is performed such that the greater the amount of reflected light that can be detected by the detection unit 22, the narrower the distance between the detection unit 22 and the medium support unit 30.

  However, in this calculation method, when disturbance light may enter the detection unit 22, the amount of reflected light detected by the detection unit 22 is larger than the actual amount of reflected light, so that the interval is reduced. There is a risk of being. Therefore, in the present embodiment, in order to calculate the interval between the detection unit 22 and the medium support unit 30 while suppressing the influence of disturbance light, the interval is calculated as described below.

  Next, with reference to FIGS. 6-8, the calculation method of the space | interval D of the detection part 22 and the medium support part 30 in this embodiment is demonstrated. Here, FIGS. 6 and 7 show the arrangement relationship and the light amount distribution between the detection unit 22 and the reflection pattern RP when the distance D between the detection unit 22 and the medium support unit 30 (reflection pattern RP) is different. . 6A and 7A show the reflection pattern RP so as to have a thickness in the vertical direction Z for easy understanding of the explanation.

  Further, the interval D between the detection unit 22 and the medium support unit 30 in the present embodiment is the interval D between the detection unit 22 and the reflection pattern RP formed on the retracting unit 323 of the frame body 32, and hence the following description. Then, the interval D between the detection unit 22 and the medium support unit 30 is also referred to as “the interval D between the detection unit 22 and the reflection pattern RP”.

  As shown in FIG. 6A, when the interval D between the detection unit 22 and the reflection pattern RP is the first interval D1, the light amount distribution of the reflected light from the reflection pattern RP in the width direction X is as shown in FIG. The light quantity distribution is as shown in FIG. That is, when the high reflection part RP1 is a detection target, the light diffused toward the high reflection part RP1 is easily reflected by the high reflection part RP1, and the amount of reflected light LV detected by the detection part 22 is large. Become.

  On the other hand, when the low reflection portion RP2 is a detection target, the light diffused and irradiated toward the low reflection portion RP2 becomes difficult to be reflected by the low reflection portion RP2, and the amount of reflected light LV detected by the detection portion 22 is small. Become. Thus, in the case shown in FIG. 6, the maximum light amount LV1 that is the amount of reflected light when the high reflection portion RP1 is the detection target and the minimum amount that is the light amount of the reflected light when the low reflection portion RP2 is the detection target. A light amount difference ΔLV that is an absolute value of a difference from the light amount LVs is a first light amount difference ΔLV1.

  As shown in FIG. 7A, when the distance D between the detection unit 22 and the reflection pattern RP is the second distance D2 wider than the first distance D1, the distance from the reflection pattern RP in the width direction X The light quantity distribution of the reflected light is a light quantity distribution as shown in FIG. That is, when the high reflection part RP1 is a detection target, the light diffused toward the high reflection part RP1 is easily reflected by the high reflection part RP1, and the amount of reflected light LV detected by the detection part 22 is large. Become.

  However, compared with the light amount distribution shown in FIG. 6B, the light amount LV (maximum light amount LVl) of the reflected light in the high reflection portion RP1 is reduced. This is because the distance D between the detection unit 22 and the reflection pattern RP is widened, so that a part of the light diffused from the detection unit 22 is applied to the low reflection unit RP2 adjacent to the high reflection unit RP1 to be detected. This is because it becomes easy to enter, and the reflected light from the low reflection part RP2 cannot be received by the detection part 22.

  On the other hand, when the low reflection portion RP2 is a detection target, the light diffused and irradiated toward the low reflection portion RP2 becomes difficult to be reflected by the low reflection portion RP2, and the amount of reflected light LV detected by the detection portion 22 is small. Become. However, compared with the light amount distribution shown in FIG. 6B, the light amount LV (minimum light amount LVs) of the reflected light in the low reflection part RP2 is increased. This is because the distance D between the detection unit 22 and the reflection pattern RP is widened so that a part of the light diffused from the detection unit 22 is applied to the high reflection unit RP1 adjacent to the low reflection unit RP2 to be detected. This is because the light that is incident and reflected by the high reflection portion RP <b> 1 is received by the detection unit 22.

  Thus, in the case shown in FIG. 7, the maximum light amount LV1 that is the amount of reflected light when the high reflection portion RP1 is the detection target, and the minimum light amount that is the reflection light when the low reflection portion RP2 is the detection target. A light amount difference ΔLV that is an absolute value of a difference from the light amount LVs is a second light amount difference ΔLV2 that is less than the first light amount difference ΔLV1.

  Therefore, in the control unit 60 of the present embodiment, when the light amount difference ΔLV is large, calculation is performed so that the interval D between the detection unit 22 and the reflection pattern RP is narrower than when the light amount difference ΔLV is small. It was decided. In this regard, in the present embodiment, the control unit 60 corresponds to an example of a “calculation unit”. In practice, it is desirable to calculate the interval D with reference to the map shown in FIG.

  The map shown in FIG. 8 shows the amount of reflected light LV (minimum amount of light LV1) when the high reflection portion RP1 is a detection target and the amount of reflected light LV (minimum amount of light LVs) when the low reflection portion RP2 is a detection target. The relationship between the light amount difference ΔLV and the distance D between the detection unit 22 and the reflection pattern RP is shown. As shown in FIG. 8, the first interval D1 when the first light amount difference ΔLV1 is smaller than the second interval D2 when the second light amount difference ΔLV2 is smaller than the first light amount difference ΔLV1. It is narrower.

  According to this map, when the light amount difference ΔLV can be calculated based on the detection result of the detection unit 22, the interval D according to the light amount difference ΔLV can be acquired. The map shown in FIG. 8 obtains the relationship between the light amount difference ΔLV and the interval D by acquiring the light amount distribution when the interval D between the detection unit 22 and the reflection pattern RP is changed in advance through experiments or the like. It is desirable to keep it. That is, the light amount difference ΔLV and the interval D do not necessarily have a linear relationship.

  Further, since the interval D obtained in this way is the interval D between the detection unit 22 and the reflection pattern RP, the interval D between the droplet discharge unit 21 and the medium support unit 30 or between the droplet discharge unit 21 and the medium support unit 30. When it is desired to obtain the distance D between the supported medium M, it is desirable to appropriately correct the distance D between the detection unit 22 and the reflection pattern RP.

  That is, in the direction in which the detection unit 22 and the reflection pattern RP face each other (vertical direction Z), the distance between the reflected light receiving surface of the detection unit 22 and the nozzle formation surface of the droplet discharge unit 21, What is necessary is just to correct | amend by acquiring previously the space | interval of the surface 322 and the formation surface of the reflective pattern RP in the retracting part 323, and adjusting the space | interval to the said space | interval D.

Next, the operation of the printing apparatus 10 of the present embodiment will be described with reference to FIGS.
In the printing apparatus 10 of the present embodiment, when printing on the medium M, the medium support unit 30 is moved to the set position, and the medium M is set by the user. Then, in accordance with a print instruction from the user, the medium support unit 30 is transported from the set position in the transport direction −Y.

  Specifically, as shown in FIG. 9A, the medium support unit 323 so that the retracting unit 323 of the frame 32 of the medium support unit 30 and the detection unit 22 supported by the carriage 23 overlap in the transport direction Y. The unit 30 is transported from the set position in the transport direction -Y. Here, when the medium support unit 30 is transported in the transport direction −Y, the carriage 23 is moved to the end in the width direction X so that the carriage 23 does not overlap the medium support unit 30 in the width direction X. Is desirable. Subsequently, with the movement of the carriage 23 in the width direction X (+ X), the detection operation is performed so that the detection unit 22 crosses the frame 32 in which the reflection pattern RP is formed in the width direction X.

  Here, as illustrated in FIG. 9B, in the detection operation, the interval D between the detection unit 22 and the reflection pattern RP is wider than the interval between the detection unit 22 and the surface of the frame body 32. For this reason, in the detection operation, a sufficient distance can be provided between the detection unit 22 and the frame 32 (retraction unit 323) on which the reflection pattern RP is formed, and the detection unit 22 and the frame 32 are in contact with each other. The situation to do is avoided.

  Then, by performing the detection operation, for example, a light amount distribution as shown in FIG. 10B is obtained for the reflection pattern RP shown in FIG. Here, for easy understanding of the explanation, the reflection pattern RP is shown in FIG. 10A so as to have a thickness in the vertical direction Z, and FIG. 10B shows the detection operation under different conditions (three conditions). The light quantity distribution obtained when performing is shown.

  In FIG. 10B, the light amount distribution when the interval D between the detection unit 22 and the reflection pattern RP is the first interval (hereinafter also referred to as “first interval D1r”) is indicated by a solid line. The light amount distribution when the interval D is a second interval wider than the first interval D1r (hereinafter also referred to as “second interval D2r”) is indicated by a broken line. The distance D is a third distance (hereinafter also referred to as “third distance D3r”) equal to the second distance D2r, and disturbance light corresponding to the light quantity LVd is incident on the detection unit 22. The light quantity distribution is indicated by a one-dot chain line.

  Here, as shown in FIG. 10B, the light quantity LVd is a difference between the light quantity LV indicated by a broken line and the light quantity LV indicated by a one-dot chain line. In addition, the first interval D1r, the second interval D2r, and the third interval D3r are not estimated values calculated based on the detection result of the detection unit 22, but are actual values.

  First, as a comparative example, a case will be described in which the distance D between the detection unit 22 and the reflection pattern RP is acquired according to the maximum light amount LV1 that is the amount of reflected light when the high reflection portion RP1 is a detection target. In this case, the calculation is performed so that the interval D between the detection unit 22 and the reflection pattern RP becomes narrower as the maximum light quantity LVl increases.

  In FIG. 10B, when the interval D between the detection unit 22 and the reflection pattern RP is the first interval D1r indicated by the solid line, the maximum light amount LV1 is set as the first maximum light amount LV11. Further, when the interval D is the second interval D2r indicated by a broken line, the maximum light amount LVl is the second maximum light amount LVl2 less than the first maximum light amount LVl1, and the interval D is a third dotted line. In the case of the interval D3r, the maximum light amount LVl is set to a third maximum light amount LVl3 that is larger than the first maximum light amount LVl1.

  That is, the magnitude relationship of the distance D between the actual detection unit 22 and the reflection pattern RP is “the first distance D1r <the second distance D2r = the third distance D3r”. The magnitude relationship is “third maximum light amount LVl3> first maximum light amount LVl1> second maximum light amount LV12”.

  For this reason, in the comparative example, when the disturbance light is not detected by the detection unit 22 at the point where the first maximum light amount LVl1 is larger than the second maximum light amount LVl2, "first interval D1r <second interval". The interval D can be calculated to satisfy the actual relationship of “D2r”. However, when the disturbance light is detected by the detection unit 22 in that the third maximum light amount LV13 is larger than the second maximum light amount LV12, the actual value of “second interval D2r = third interval D3r”. The interval D cannot be calculated so as to satisfy the relationship.

  In contrast, in the present embodiment, the maximum light amount LV1 that is the amount of reflected light when the high reflection portion RP1 is the detection target, and the minimum light amount that is the light amount of the reflected light when the low reflection portion RP2 is the detection target. An interval D between the detection unit 22 and the reflection pattern RP is acquired according to a light amount difference ΔLV that is an absolute value of a difference from LVs. In this case, as shown in FIG. 8, the calculation is performed so that the interval D between the detection unit 22 and the reflection pattern RP becomes narrower as the light amount difference ΔLV increases.

  In FIG. 10B, when the distance D between the detection unit 22 and the reflection pattern RP is the first distance D1r indicated by the solid line, the light amount difference ΔLV becomes the first light amount difference ΔLV1. When the distance D is the second distance D2r indicated by a broken line, the light quantity difference ΔLV is a second light quantity difference ΔLV2 that is less than the first light quantity difference ΔLV1, and the distance D is a third dotted line. When the distance is D3r, the light amount difference ΔLV is a third light amount difference ΔLV3 that is equal to the second light amount difference ΔLV2.

  In other words, the magnitude relationship of the interval D between the actual detection unit 22 and the reflection pattern RP is “first interval D1r <second interval D2r = third interval D3r” and the magnitude relationship of the light amount difference ΔLV. “First light amount difference ΔLV1> second light amount difference ΔLV2 = third light amount difference ΔLV3”.

  For this reason, in the present embodiment, when the disturbance light is not detected by the detection unit 22 in that the first maximum light amount LVl1 is larger than the second maximum light amount LVl2, “first interval D1r <second The interval D can be calculated so as to satisfy the actual relationship of the interval D2r. Further, even when the disturbance light is detected by the detection unit 22 at a point where the third maximum light amount LV13 is equal to the second maximum light amount LV12, the actual value of “second interval D2r = third interval D3r” is satisfied. The interval D can be calculated so as to satisfy the relationship.

  Then, after the interval D between the detection unit 22 and the reflection pattern RP is calculated, if the interval D is an appropriate interval, a printing operation is started, and the interval D is an inappropriate interval. The printing operation is not started. Thus, for example, when the droplets are ejected from the droplet ejection unit 21 in a state where the distance D is too wide, the generation of a large amount of mist that is smaller than the droplets is suppressed.

According to the embodiment described above, the following effects can be obtained.
(1) According to a light amount difference ΔLV that is an absolute value of a difference between a reflected light amount LV when the high reflection portion RP1 is a detection target and a reflected light amount LV when the low reflection portion RP2 is a detection target. Thus, the interval D between the detection unit 22 and the reflection pattern RP is calculated. For this reason, the distance D can be calculated after subtracting the influence of disturbance light. According to this, the detection unit 22 and the detection unit 22 can be configured with a simple configuration without newly providing a distance sensor or the like that measures the distance to the medium support unit 30 according to the light reception position of the reflected light in the light reception unit 222 of the detection unit 22. The distance D from the reflection pattern RP can be measured. Further, usually, the distance between the droplet discharge section 21 and the medium support section 30 is determined based on the distance between the droplet discharge section 21 and the detection section 22 determined by design and the distance D between the detection section 22 and the reflection pattern RP. The interval can be measured.

  (2) Since the high reflection part RP1 and the low reflection part RP2 are arranged in the width direction X in the reflection pattern RP, the detection operation can be performed when the carriage 23 is moved in the width direction X. That is, it is not necessary to newly provide a separate configuration for detecting the light quantity LV of the reflected light from the high reflection part RP1 and the low reflection part RP2, and it is possible to easily detect the light quantity LV of the reflected light.

  (3) The retracting portion 323 is provided at the end of the frame body 32 in the transport direction −Y, and the reflection pattern RP is formed in the retracting portion 323. Therefore, when the detection unit 22 detects the light quantity LV of the reflected light from the reflection pattern RP, the retracting unit 323 of the medium support unit 30 and the detection unit 22 supported by the carriage 23 overlap in the transport direction + Y. In such a state, the carriage 23 is moved in the width direction X. For this reason, it is possible to perform the detection operation with a sufficient space between the detection unit 22 and the medium support unit 30 as compared with the case where the retracting unit 323 is not formed.

  (4) Since the droplet discharge unit 21 is arranged on the transport direction + Y side with respect to the detection unit 22, the detection operation is performed in a state where the medium support unit 30 and the droplet discharge unit 21 do not overlap in the transport direction Y. It can be carried out. That is, contact between the medium support unit 30 and the droplet discharge unit 21 can be avoided.

(5) Since the medium M is supported by the mounting table 31 and the frame body 32, the medium M can be supported more reliably than when the medium M is mounted on the mounting table 31. .
(6) The printing operation is limited according to the interval D between the droplet discharge unit 21 and the medium support unit 30 acquired based on the detection result of the detection unit 22. For this reason, for example, when the user sets the medium M on the medium support unit 30, the printing operation is executed with an unreasonably wide space D, for example, when the medium support unit 30 is moved vertically downward. Thus, an increase in the amount of mist generated can be suppressed.

In addition, you may change the said embodiment as shown below.
It is desirable that the mounting table 31 and the frame body 32 can be changed according to the size of the medium M and the size of the image to be printed on the medium M. In this case, it is desirable that the mounting table 31 be detachable from the support table 33.

  When the frame 32 having a different size is used, the reflection pattern RP formed on the frame 32 according to the size of the frame 32 (the size in at least one of the transport direction Y and the width direction X). The arrangement of the high reflection part RP1 and the low reflection part RP2 may be changed. For example, when the frame 32 includes a small frame, a medium frame, and a large frame, the reflection pattern RP formed on the small frame is “001001. The reflection pattern RP formed on the large frame may be “011011...” And the reflection pattern RP formed on the large frame may be “110110.

  According to this, the size of the frame 32 can be specified by whether the minimum unit of the repetition rule of the reflection pattern RP is “001”, “011”, or “110”.

  In addition, when a different reflection pattern RP is formed depending on the type of the frame body 32, the reflection pattern RP of the frame body 32 that can be used in advance may be registered in the printing apparatus 10. According to this configuration, it is possible to prevent printing when the frame body 32 that cannot be used is mounted on the mounting table 31 of the medium support unit 30.

  -You may connect the mounting base 31 and the frame 32 via a hinge (hinge). In this case, when the frame body 32 rotates relative to the mounting table 31, the frame body 32 is attached to the mounting table 31 or the frame body 32 is removed from the mounting table 31.

The reflection pattern RP may be formed across the width direction X in the retracting portion 323.
The reflection pattern RP may be arranged in the transport direction Y in the frame body 32. In this case, the detection operation is performed by transporting the medium support unit 30 in the transport direction Y.

  In the above embodiment, the printing operation is performed when the medium support unit 30 moves in the transport direction + Y. However, the printing operation may be performed when the medium support unit 30 moves in the transport direction -Y. . In this case, it is desirable that the droplet discharge unit 21 is arranged in the transport direction −Y rather than the detection unit 22.

  In the state where the medium support unit 30 is most vertically raised, it is desirable that the distance D between the detection unit 22 and the reflection pattern RP (retraction unit 323) is larger than “0 (zero)”. Further, it is preferable that the detection unit 22 protrudes most toward the medium support unit 30 in the carriage 23 as compared with other components such as the droplet discharge unit 21.

  According to this, even when the medium support unit 30 is closest to the carriage 23 in the vertical direction, it is possible to prevent the detection unit 22 and the retracting unit 323 from contacting each other in the detection operation. In addition, it is possible to prevent a situation in which another constituent member such as the droplet discharge unit 21 contacts the retracting unit 323.

In the transport direction Y, the droplet discharge unit 21 may be disposed at the same position as the detection unit 22.
The retraction part 323 may not be provided in the frame body 32. In this case, it is desirable to form the reflection pattern RP at the end of the frame 32 on the transport direction −Y side.

  The frame body 32 may not be provided on the medium support unit 30. In other words, the medium M may be simply placed on the placement table 31. In this case, it is desirable to form the reflection pattern RP on the medium support unit 30 (for example, the mounting table 31).

  Furthermore, in this case, not only the change in the interval between the droplet discharge unit 21 and the medium support unit 30 due to the driving of the elevating motor 43 but also the droplets by exchanging the medium support unit 30 (for example, the mounting table 31). It is also possible to detect a change in the interval when the interval between the ejection unit 21 and the medium support unit 30 changes. That is, the above embodiment is a printing apparatus in which the medium support part 30 or a part of the medium support part 30 can be replaced even if the distance between the droplet discharge unit 21 and the medium support part 30 cannot be changed. Applicable if available.

  The printing apparatus 10 may perform unidirectional printing in which droplets are ejected to the droplet ejection unit 21 only when the carriage 23 moves in one direction of the width direction + X and the width direction −X. May move in both the width direction + X and the width direction -X, and bi-directional printing in which droplets are ejected by the droplet ejection unit 21 may be performed.

The medium M is not limited to a fabric such as a T-shirt, and may be another medium M. For example, it may be paper or a resin film.
The printing apparatus 10 may not be a serial printer that ejects ink while the droplet discharge unit 21 reciprocates in the width direction X. For example, a line printer that ejects ink in a state where the droplet discharge unit 21 has a length corresponding to the entire width of the medium M and is fixedly arranged may be used.

  The detection unit 22 may be a line sensor in which a plurality of light emitting units 221 and light receiving units 222 are arranged in the width direction X. According to this, it is possible to irradiate light toward the reflection pattern RP and detect the amount of reflected light without moving the detection unit 22 in the width direction X.

  The printing apparatus 10 may be a droplet discharge device that discharges droplets toward the medium M. That is, the liquid ejected by the droplet ejection unit 21 is not limited to ink, and may be, for example, a liquid material in which functional material particles are dispersed or mixed in the liquid. For example, recording is performed by ejecting a liquid material in which a material such as an electrode material or a color material (pixel material) used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display is dispersed or dissolved. It may be configured.

  DESCRIPTION OF SYMBOLS 10 ... Printing apparatus (an example of a droplet discharge device), 21 ... Droplet discharge part, 22 ... Detection part, 221 ... Light emission part, 222 ... Light reception part, 23 ... Carriage, 30 ... Medium support part, 31 ... Mounting stand, 32 ... Frame body, 323 ... Retraction unit, 60 ... Control unit (an example of a calculation unit), D ... interval, D1 ... first interval, D2 ... second interval, LV ... light amount, LVl ... maximum light amount, LVs ... Minimum light quantity, ΔLV ... light quantity difference, ΔLV1 ... first light quantity difference, ΔLV2 ... second light quantity difference, ΔLV3 ... third light quantity difference, M ... medium, PA ... printing area (an example of ejection area), RP ... reflection Pattern, RP1 ... high reflection part, RP2 ... low reflection part, X ... width direction (an example of the second direction), Y ... conveyance direction, + Y ... conveyance direction (an example of the first direction).

Claims (6)

A medium support for supporting the medium;
A droplet discharge unit that discharges droplets to a discharge region of the medium supported by the medium support unit;
A detection unit that detects the amount of reflected light of the light irradiated toward the medium support unit or the medium supported by the medium support unit;
A calculation unit that calculates an interval between the detection unit and the medium support unit based on a detection result of the detection unit;
The medium support portion is formed with a reflection pattern in which a high reflection portion having a high reflectance and a low reflection portion having a low reflectance are repeatedly arranged.
The calculation unit calculates the interval so that the larger the light amount difference between the amount of reflected light from the low reflection unit detected by the detection unit and the amount of reflected light from the high reflection unit is, the narrower the interval is. A droplet discharge device characterized by the above. The medium support portion moves in a first direction while supporting the medium, and
A carriage that reciprocates in a second direction that intersects the first direction while supporting the droplet discharge unit and the detection unit;
The droplet ejection apparatus according to claim 1, wherein the reflection pattern includes the high reflection portion and the low reflection portion that are repeatedly arranged in the second direction. The medium support portion is formed with a retracting portion that is recessed so as to be away from the carriage in a direction intersecting both the first direction and the second direction at an end portion in the first direction. And
The droplet discharge device according to claim 2, wherein the reflection pattern is formed in the retracting portion. The droplet discharge device according to claim 3, wherein the droplet discharge unit is disposed closer to the first direction than the detection unit in the carriage. The medium support unit includes a mounting table on which the medium is mounted, and a frame body that presses the medium against the mounting table by being mounted on the mounting table so as to border the discharge area. ,
The liquid droplet ejection apparatus according to claim 1, wherein the reflection pattern is formed in a region of the frame that faces the detection unit. The control part which restrict | limits discharge of the droplet of the said droplet discharge part based on the said space | interval which the said calculating part calculated is provided. The control part as described in any one of Claims 1-5 characterized by the above-mentioned. Droplet discharge device.