JP2001328246A - Ink-jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording device capable of certainly detecting lift-up of a recording medium from a platen before collision with an ink-jet head, and capable of certainly preventing the collision of the ink-jet head with the lift-up. SOLUTION: This device comprises a carriage 16 for supporting a plurality of ink-jet heads 10 having a plurality of ink-jet nozzles 10a for jetting an ink, reciprocally movable in the main scanning direction parallel witch the facing recording medium surface, a control means 34 for controlling the reciprocal movement of the carriage, and a collision alarm sensor 40 disposed forward in the movement direction with respect to the ink-jet heads 10 at the time of moving the carriage 16, for detecting lift-up of a paper as a recording medium by a predetermined amount or more between the two ink-jet nozzles 10a-10a disposed at both ends in the sub scanning direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly, to an ink jet head having a plurality of ink jet nozzles, a carriage holding the ink jet head and capable of reciprocating in the main scanning direction, and reciprocating the carriage. Control means for controlling the movement, and while moving the carriage to at least one of the reciprocating movement, ejects ink from the inkjet head toward the recording medium to record an image on the recording medium, The present invention relates to an ink jet recording apparatus that conveys a recording medium by a predetermined width in a sub-scanning direction at every predetermined number of movements.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, a carriage holding an ink jet head is moved in a first direction parallel to a recording medium surface in order to accurately and accurately record an image on an opposing recording medium. While recording an image by reciprocating along the main scanning direction as described above, it is necessary to maintain the gap between the plurality of inkjet nozzles of the inkjet head and the recording medium at an optimal gap for recording.
This optimum gap is very narrow and must be kept constant over the recording range. For this reason, the recording medium is usually placed on a platen to maintain its flatness.

[0003]

However, the recording medium often floats on the platen for various reasons. If the recording medium floats greatly, the carriage that reciprocates as described above or the ink jet head mounted thereon may collide with the raised portion. As a result, the precision inkjet nozzle may be damaged.

A collision warning sensor for preventing such a collision is already known from Japanese Patent Application Laid-Open No. Sho 64-45677. This conventional collision warning sensor has a contact piece extending toward the recording medium from the tip of the inkjet head that moves relatively to the recording medium on the platen. Then, when the recording medium rises on the platen and the gap between the recording medium and the tip of the inkjet head becomes smaller than a predetermined value, the contact piece is moved earlier than the tip of the inkjet head collides with the floating portion of the recording medium. By contacting the floating portion of the recording medium and stopping the movement of the ink jet head, collision between the ink jet head and the recording medium is prevented.

However, this conventional collision warning sensor is effective when the floating of the recording medium from the platen extends in a direction intersecting with the moving direction of the ink jet head. If it extends along the direction of travel,
If it occurs in the form of a dot at a position slightly displaced from the tip of the contact piece, there is a high possibility that it cannot be detected.

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances. In any state of the rising of a recording medium from a predetermined position such as on a platen, the ink jet head is required to be moved before the ink jet head collides with the rising. It is an object of the present invention to provide an ink jet recording apparatus capable of surely detecting the above-mentioned lifting and reliably preventing the collision of the ink jet head with the rising of the recording medium.

[0007]

In order to achieve the object of the present invention as described above, an ink jet recording apparatus according to the present invention comprises: an ink jet head having a plurality of ink jet nozzles for jetting ink; A carriage that holds and reciprocates in a first direction parallel to a facing recording medium surface; a control unit that controls the reciprocation of the carriage; Between the two inkjet nozzles located at both ends in a second direction intersecting with the first direction, the inkjet head being opposed to the first direction by a predetermined amount or more of the recording medium facing the inkjet head. And a collision warning sensor for detecting paper floating.

According to the ink jet recording apparatus having such a configuration, it is possible to detect the floating of the recording medium that causes a collision over the recording width of the ink jet head, that is, the entire width of the ink jet nozzle array. To play.

In the ink jet recording apparatus according to the present invention having such a configuration, the control means moves the carriage when the collision warning sensor detects that the paper floats above the predetermined amount. Is preferably stopped.

In order to achieve the object of the present invention as described above, the ink jet recording apparatus according to the present invention also comprises:
An inkjet head having a plurality of inkjet nozzles for ejecting ink; a head holder that holds the inkjet head and is capable of reciprocating in a direction perpendicular to the surface of the recording medium facing the inkjet head; A carriage for holding and reciprocating in a first direction parallel to the facing recording medium surface;
Control means for controlling reciprocation of the carriage; both ends in a second direction intersecting with the first direction, provided on the head holder so as to be located forward of the ink jet head when the carriage is moved. And a collision warning sensor for detecting a floating of a predetermined amount or more of the recording medium facing the ink jet head between the two ink jet nozzles located at the same position.

According to the ink jet recording apparatus having such a configuration, it is possible to detect a floating of the recording medium that causes a collision over the recording width of the ink jet head, that is, the entire width of the ink jet nozzle array. To play.

In the ink jet recording apparatus according to the present invention having such a configuration, when the collision warning sensor detects the floating of the paper by the predetermined amount or more, the control means controls the movement of the carriage. Movement can be stopped. Further, the head holder can be kept away from the recording medium. Furthermore, the movement of the carriage can be stopped, and the head holder can be moved away from the facing recording medium.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically shows a main part of an ink jet recording apparatus according to an embodiment of the present invention, in which (A) is a front view, (B) is a plan view,
(C) is a right side view; FIG. 2 is an enlarged schematic left side view of a main part of the ink jet recording apparatus; FIG. 3 is an ink jet head of a head holder of the main part of the ink jet recording apparatus. FIG. 4A is an enlarged partial cross-sectional view showing a state where a collision warning sensor of a main part of an ink jet recording apparatus has been operated; And FIG. 4B is an enlarged partial plan view showing a state in which the carriage has stopped moving immediately after the collision warning sensor of the main part of the ink jet recording apparatus has been operated.

First, referring to FIGS. 1 to 3,
A schematic configuration of a main part of the inkjet recording apparatus according to the present embodiment will be described.

This ink jet recording apparatus has six ink jet heads 10K, 1K each provided with a plurality of ink jet nozzles 10a each having a predetermined arrangement.
0C, 10M, 10LC, 10LM, and 10Y. The ink jet head 10K is black, 10C is cyan, 10M is magenta, 10LC is light cyan,
LM corresponds to light magenta, 10Y corresponds to yellow, and these inkjet heads 10K, 10C, 1
0M, 10LC, 10LM, and 10Y are arranged on the head holder 14 in a predetermined arrangement. It is not shown from a main ink bottle containing black ink, cyan ink, magenta ink, light cyan ink, light magenta ink, and yellow ink mounted on a fixed frame (not shown) of the ink jet recording apparatus. The ink of the corresponding color is supplied by the ink supply pump through a flexible ink supply tube (not shown) having flexibility.

The carriage 16 is movable in a predetermined range by a pair of guide rods 18a and 18b extending along a main scanning direction (a left-right direction in FIG. 1A) as a first direction. Supported. More specifically, in this embodiment, a pair of guide bars 18a, 1
8b is vertically separated in the sub-scanning direction (the vertical direction in FIG. 1A) as the second direction,
Are a plurality of rollers 16b, 16a provided above and below
, Are movably supported in the main scanning direction along upper and lower guide rods 18a and 18b.

The carriage 16 has a rectangular frame shape, and a head holder 14 for holding six ink jet heads is arranged in the center space. The head holder 14 has a pair of upper and lower guide rods 14a and 14b that are inserted into a pair of thrust bearings 20a and 20b provided on the upper and lower beams of the carriage 16, respectively. The pair of guide rods 14a and 14b extend in a direction intersecting the main scanning direction and the sub-scanning direction, that is, a direction intersecting the recording medium surface.
a, a pair of thrust bearings 20a, 20b
Is guided in a predetermined range along the arrow, so that the inkjet head 10 can be moved in the direction of moving toward or away from the recording medium (the left-right direction in FIG. 3).

FIG. 3 shows a solid line of the head holder 14 and the guide rod 14a when the head holder 14 and the guide rod 14a are closest to the recording medium 24. The guide rod 14a is indicated by a two-dot chain line. Note that the position of the other guide rod 14b relative to the recording medium 24 is different from that of the guide rod 14a.
The illustration is omitted because it is the same as the case of FIG.

This ink jet recording apparatus includes an ink jet head contacting / separating mechanism for moving the head holder 14 toward and away from the recording medium 24 within a predetermined range.
This ink jet head contact / separation mechanism includes a head holder 1
4 has a biasing means UM for biasing the recording medium 4 away from the recording medium 24. In this embodiment, the urging means U
M is a pair of guide rods 14a, 14b of the head holder 14.
And a pair of thrust bearings 20a, 20b of the carriage 16
And a compression coil spring wound around the pair of guide rods 14a and 14b.

The ink jet head contact / separation mechanism further comprises:
Behind the pair of guide rods 14a, 14b of the head holder 14, there is a pair of head holder driving rods 26a, 26b extending along the main scanning direction, and a pair of head holder driving Both ends of the rods 26a and 26b are rotatably supported by the carriage 16. An eccentric cam 28 is fixed to the pair of head holder driving rods 26 a and 26 b, and the peripheral surface of the eccentric cam 28 contacts the rear surface of the head holder 14.

A pair of head holder driving rods 26a, 26b
, A timing belt 30 is wound around the eccentric cams 28 in order to rotate them synchronously. A pulse motor 32 is connected to the lower head holder driving rod 26b. The driving force generated by the forward / reverse rotation of the pulse motor 32 causes synchronous forward / reverse rotation of the lower head holder driving rod 26b and the upper head holder driving rod 26a via the timing belt 30. By the forward / reverse rotation of the pair of head holder driving rods 26a, 26b, the eccentric cam 28 causes the head holder 14 to approach the recording medium 24 against the urging force of the urging means UM and the urging force of the urging means 26. From the recording medium 24 is performed.

The pulse motor 32 is connected to the control means 34 and is controlled by the control means 34. Control means 3
4 is also connected to known driving means (not shown) for the six inkjet heads 10.

The carriage 16 is driven by a known driving means 36, and is supported by a pair of guide rods 18a and 18b and is capable of reciprocating in the main scanning direction.

The driving means 36 includes a pair of pulleys (not shown) provided at both ends in the main scanning direction, a timing belt (not shown) which is wound around the pair of pulleys and is fixed to the carriage 16, and a pair of pulleys. And a pulse motor (not shown) for driving one of them. The pulse motor of the driving means 36 is also connected to the control means 34,
The driving is controlled by the control means 34.

In this embodiment, a pair of collision warning sensors 40 are provided on both sides of the head holder 14 in the main scanning direction. This pair of collision warning sensors 4
Numeral 0 is disposed outside the six inkjet heads 10 in the main scanning direction. A pair of collision warning sensors 40
Are arranged upside down, but the configuration and operation are the same. This is because the configuration of the pair of collision warning sensors 40 is made common and the number of parts is reduced, thereby lowering the manufacturing cost.

Each of the pair of collision warning sensors 40 is provided between the ink jet nozzles 10a (ink jet head 10K) located at least at both ends in the sub-scanning direction (the direction intersecting the reciprocating direction of the carriage 16).
Inkjet head 10a located at the uppermost position
And the ink jet head 10Y positioned at the lowest position of the ink jet head 10Y) to detect the floating of the recording medium 24 by a predetermined amount or more.

More specifically, each of the pair of collision warning sensors 40 includes a fixed plate 42 fixed at a predetermined position on both sides of the head holder 14 in the main scanning direction which is the reciprocating direction of the carriage 16. A detection piece 46 on a plate supported by the fixed plate 42 so as to be rotatable about a rotation center line 44 extending in the sub-scanning direction;
Elastic holding means 48 for elastically holding at a predetermined rotation position toward the camera, and rotation detecting means 50 for detecting the rotation of the detecting piece 46 by a predetermined amount or more against the elastic holding force of the elastic holding means 48.
And

The detection piece 46 is configured so that its own center of gravity G is arranged on the rotation center line 44. For this reason, the detection piece 46 is rotatably supported on the fixed plate 42 most stably, that is, without being affected by disturbance (for example, inertial force due to reciprocal movement or stoppage of the carriage 16). I have.

The elastic holding means 48 is an elastic member stretched between the fixed plate 42 and the detecting piece 46, and is constituted by a tension coil spring. The elastic holding means 48
The detection piece 46 is urged against the fixed plate 42 by a predetermined elastic force to hold the detection piece 46 at a predetermined rotation position (sensor home position) and to detect the detection piece 46 by a disturbance equal to or less than the predetermined elastic force. This prevents the rotation of the sensor 46 from the sensor home position by the predetermined amount or more and the detection by the rotation detecting means 50.

In this embodiment, the elastic force exerted by the elastic holding means 48 on the detecting piece 46 is set between approximately 0.5 g and approximately 10 g.

At the sensor home position, the detection piece 46 is disposed at substantially 90 degrees with respect to the recording medium 24 facing the same, as is apparent from FIG.

The rotation detecting means 50 has a photo interrupter 54 fixed on the fixing plate 42 and a swinging piece 52 formed integrally with the detecting piece 46. Each member of the rotation detecting means 50 causes the swinging piece 52 to move along the optical path of the photo-interrupter 54 while the detection piece 46 is rotated by a predetermined amount or less, including when the detection piece 46 is held at the sensor home position. When the detection piece 46 is rotated by a predetermined amount or more from the sensor home position, the swing piece 5
2 is configured so that the light interrupted state of the photo interrupter 54 is released. Then, when the rocking piece 52 releases the light interrupted state of the photo interrupter, a collision warning signal indicating that the rotation has been performed by a predetermined amount or more is generated. This collision warning signal is applied to the control means 34.

In FIG. 1A, the position of the uppermost ink jet nozzle 10a in the sub scanning direction in the ink jet head 10K positioned at the uppermost position in the sub scanning direction is indicated by a one-dot chain line HP. Have been.
Further, the position in the sub-scanning direction of the ink jet nozzle 10a located at the lowermost end in the ink jet head 10Y located at the lowest position in the sub scanning direction is pointed out by the one-dot chain line LP.

As is apparent from FIGS. 1A and 1C, the detection piece 46 has two ink jet nozzles 1 located at both ends in the sub-scanning direction, that is, at the upper end and the lower end.
0a, and extend upward and downward beyond the both ends.

In particular, the detection piece 46 is located at the position H of the ink jet nozzle 10a located at the upper end in the sub-scanning direction.
A predetermined distance X extends further upward from P. It is preferable that the predetermined distance X is set to an extent corresponding to the length of the inkjet nozzle row of at least one inkjet head. That is, in the intermittent paper conveyance at the time of image recording, it is preferable that the intermittent paper conveyance is set to the extent corresponding to the conveyance amount per one time in the one-pass printing mode having the largest conveyance amount.

In front of each ink jet head 10,
A flat platen 22 that supports the recording medium 24 is disposed.

The recording medium 24 in this embodiment is
It has a web shape having a width of a predetermined length in the main scanning direction on the platen 22, and is moved upward along the sub-scanning direction on the platen 22 by a known recording medium conveying means (not shown) during image formation. The paper is conveyed intermittently downward from the printer at intervals and widths according to various recording modes. The material of the recording medium 24 is not particularly limited as long as ink droplets ejected from the inkjet nozzle 10a adhere thereto, and may be paper, cloth, or a plastic film, for example.

The surface of the platen 22 has a number of suction holes (not shown), and these suction holes are connected to a known negative pressure means (not shown), for example, a suction fan. Therefore, the recording medium 24 disposed on the surface of the platen 22 is subjected to
The negative pressure is set so as not to adversely affect the conveyance of the recording medium 24 by a known recording medium conveying means (not shown).

Next, the operation of the main part of the ink jet recording apparatus according to this embodiment will be described.

In the ink jet recording apparatus,
When the recording medium 24 is not placed on the platen 22,
In addition, while it is not necessary to form an image, the carriage 1
Reference numeral 6 denotes a standby position provided at one end in the main scanning direction. This standby position is called a carriage home position. Further, the head holder 14 is set at a position (the position shown by a two-dot chain line in FIG. 3) most retracted rearward (rightward in FIG. 3) relative to the carriage 16 by the urging force of the urging means 26. Called head home position.

The head holder 14 is provided inside the carriage 16 according to various statuses such as when the carriage 16 is located at the carriage home position, when performing head maintenance, when recording an image, and the like. Move within a predetermined range.

When the recording medium 24 is supplied onto the platen 22 from above in the sub-scanning direction by the recording medium conveying means from a state where the recording medium 24 is not placed on the platen 22, the carriage 16 moves in the main scanning direction. Then, an operation for detecting the state of the recording medium 24 supplied onto the platen 22 such as the width of the recording medium 24 and the state of skew is started. The control unit 34 controls the pair of the recording medium 24 until the leading end of the recording medium 24 that has reached above the platen 22 reaches the inkjet nozzle 10a located at the uppermost end HP of the inkjet head 10K located at the upper end in the sub-scanning direction. The detection output of the collision warning sensor 40 (rotation detecting means 50) is ignored.

When the recording medium 24 is stored in a roll shape, the recording medium 24 that has just reached the platen 22 has a strong curl at the tip. Due to this curl, there is a high possibility that the leading end of the recording medium 24 does not sufficiently adhere to the platen 22 and rises. Further, the platen 22 has a weak suction force with respect to the recording medium 24 that has just reached the leading end, which also causes the paper to float.

However, as described above, the recording medium 2
Even if the recording medium 4 rises above the platen 22, if it does not reach the ink jet nozzle 10a located at the upper end HP, the recording medium 24 and each ink jet head 10 do not collide with each other. The detection output of the system warning sensor 40 (rotation detecting means 50) is set to be ignored.

When a desired image is recorded on the recording medium 24 on the platen 22, first, the head holder 14 is moved to an optimum position in the carriage 16 for performing an image. Thereafter, the carriage 16 reciprocates for image recording. During the movement, the predetermined ink is ejected from the predetermined inkjet head 10 into a predetermined image area of the recording medium 24 by an instruction of the control unit 34. Let it.

Next, the operation of detecting the lifting of the recording medium 24 from the platen 22 will be described with reference to FIG.

In FIG. 4A, the image is recorded while the carriage 16 moves in the left (Y) direction in the figure.
Inkjet nozzle 1 of inkjet head 10M
FIG. 4B is a diagram illustrating a state in which the collision warning sensor 40 detects the lifting of the recording medium 24 that causes a collision at the front end of the recording medium 24a. In FIG. FIG. 16 is a diagram showing a state in which the movement of No. 16 is stopped. In FIG. 4A, the sensor home position of the detection piece 46 of the collision warning sensor 40 is indicated by a two-dot chain line.

T1 is the gap between the ink jet nozzle 10a and the recording medium, t2 is the gap between the front end of the detecting piece 46 located at the sensor home position and the recording medium 24, t3
Indicates the gap (detection distance) between the front end of the detection piece 46 and the recording medium 24 when the collision warning signal is output from the collision warning sensor 40. Here, t1
A description will be given of the relationship between the dimensions t3 to t3 as t2 <t3 ≦ t1.

As described above, the pair of collision warning sensors 4
Since the zero detection piece 46 is elastically held at the sensor home position by the elastic force of the elastic holding means 48,
The gap at t2 does not change regardless of the vibration or the wind pressure applied to the detection piece 46 during the reciprocation of the carriage 16.

If a float 24a floating by t4 (t4> t1) from the surface of the recording medium 24 occurs within the range of the movement trajectory of the front edge of the detection piece 46 accompanying the movement of the carriage 16, the float is generated. Regardless of the shape of the detecting piece 24a, as shown by the solid line in FIG.
Collides with the float 24a of the recording medium 24, and the detection piece 46 rotates around its rotation center line 44 as shown by the arrow Z against the elastic force of the elastic holding means 48. In addition, the detecting piece 46 is rotated by a predetermined rotation amount or more. This means that the collision warning sensor 40 has detected that the gap between the front end of each ink jet nozzle 10a of each ink jet head 10 and the recording medium 24 is longer than the detection distance t3, that is, that there is a possibility of collision. Means.

When the amount of rotation of the detecting piece 46 from the sensor home position exceeds a predetermined amount, the swinging piece 52 does not block the optical path of the photo interrupter 54, so that a collision warning signal is generated from the photo interrupter 54 and the control Sent to the means 34.

The control means 34 having received the collision warning signal
Immediately stops the image recording operation and stops the movement of the carriage 16 in the Y direction. As a result, FIG.
As shown by a solid line in (B), the movement of the carriage 16 is stopped before the float 24a of the recording medium 24 collides with the inkjet head 10M, and the inkjet head 10 is damaged, the already recorded image is rubbed, and the like. Quality can be prevented beforehand.

In this embodiment, the control means 34 having received the collision warning signal further controls the head holder 14 to move in the direction away from the recording medium 24 (upward in FIG. 4B). Do. By separating the inkjet head 10 from the recording medium 24 in this manner, the floating of the inkjet head 10 and the recording medium 24
Can be reduced.

The control means 34 further moves the carriage 16 in the -Y direction opposite to the Y direction, moves at least to a position where each ink jet head 10 does not face the recording medium 24, and stops at that position. As a result,
The operator can easily open the exterior cover (not shown) of the ink jet recording apparatus and easily attach or detach the portion of the recording medium 24 on the platen 22 where the floating 24a is formed, to the platen 22. .

After the operation is completed, it is preferable that the operator closes the outer cover and turns on an operation start switch (not shown) to control the ink jet recording apparatus to resume the image recording operation. .

The control means 3 having received the collision warning signal
No. 4, the carriage 16 can be reversed in the −Y direction without moving the head holder 14 in the direction of separating from the recording medium 24. However, in this case, the detection piece 46 of the collision warning sensor 40 is
4a, the control means 34 generates a collision warning signal again by rotating by a rotation amount equal to or more than a predetermined amount. From the time of reception to the time when the carriage 16 whose movement direction is reversed is moved to a position not facing the recording medium 24 and stopped at that position, the collision warning signal from the collision warning sensor 40 is ignored. I do.

While the carriage 16 is reciprocating in the main scanning direction and performing image recording, when the moving direction of the carriage 16 is reversed or stopped.
An inertial force exceeding the elastic holding force of the elastic holding means 48 is generated in the detection piece 46 of the collision warning sensor 40, and the collision warning sensor 40
Does not detect the floating 24a of the recording medium 24, the detection piece 46 may be rotated by a predetermined rotation amount or more. As a countermeasure, the control means 34 controls the collision warning sensor 40 before and after the reversal of the moving direction of the carriage 16 during image recording and before and after the movement is stopped.
It is preferable to set so as to ignore the collision warning signal from.

Further, the control means 34 further controls the carriage 16 to move outside the both ends of the recording medium 24, that is, to move the carriage 16 between It is preferable to take the above-described countermeasures even when the device is located in an area not facing the H.24.

In this embodiment, the detection piece 4
Numeral 6 extends further upward from the position HP of the inkjet nozzle 10a located at the upper end in the sub-scanning direction by a distance corresponding to the recording medium transport amount per one time in the one-pass printing mode. As a result, it is possible to detect in advance whether or not the recording medium 24 to be supplied to the area facing the inkjet head 10 has a paper float.

Further, while the carriage 16 is moving outside the image recording area while recording the image while moving along the main scanning direction, the control means 34 detects the collision warning sensor. Although the detection piece 46 may be rotated by a rotation amount equal to or more than a predetermined amount even if the detection means 46 does not detect the floating 24a of the recording medium 24, the control means 34 may be controlled in the same manner as in the above-described countermeasure. It is also conceivable to set so that the collision warning signal from the collision warning sensor 40 is ignored.

In the present embodiment, the collision warning sensor 40 is fixed to the head holder 14, but this always keeps the detection distance constant even if the thickness of the recording medium used for recording changes. It is effective in doing. However, the present invention is not limited to this, and the collision warning sensor 40 may be fixed to the carriage 16.

As described above in detail, the ink jet recording apparatus according to the present invention can be described as follows.

(1) An ink jet head having a plurality of ink jet nozzles for ejecting ink; holding the ink jet head and reciprocating in a first direction (main scanning direction) parallel to the surface of the recording medium facing the ink jet head A movable carriage; control means for controlling reciprocal movement of the carriage; and a second means provided to be located forward of the inkjet head in the movement direction when the carriage is moved, and intersecting the first direction. Between the two ink jet nozzles (between HP and LP) located at both ends in the direction (sub-scanning direction or paper transport direction), the ink jet head detects a floating of a predetermined amount or more of the recording medium facing the ink jet head. And a collision warning sensor.

(2) The ink jet recording apparatus according to (1), wherein the control means stops the movement of the carriage based on a detection output from the collision warning sensor.

(3) an ink-jet head having a plurality of ink-jet nozzles for ejecting ink; and a head holder for holding the ink-jet head and capable of reciprocating in a direction perpendicular to the surface of the recording medium facing the ink-jet head. A carriage that holds the head holder and that can reciprocate along a first direction parallel to the facing recording medium surface; control means for controlling the reciprocation of the carriage; and movement of the carriage Sometimes, the inkjet head is provided on the head holder so as to be located forward of the inkjet head, and the inkjet head is opposed between two inkjet nozzles located at both ends in a second direction intersecting with the first direction. A collision warning sensor for detecting paper floating of a predetermined amount or more of the recording medium being driven;
An ink jet recording apparatus comprising:

(4) The control means stops the movement of the carriage when receiving a collision warning signal from the collision warning sensor that detects the floating of the paper by the predetermined amount or more.
The ink jet recording apparatus according to the item (3), wherein:

(5) The control means separates the head unit holder from the recording medium when receiving a collision warning signal from the collision warning sensor, which detects that the paper floats more than the predetermined amount. The inkjet recording apparatus according to the above (3) or (4).

(6) The control means reverses the moving direction of the carriage when receiving a collision warning signal from the collision warning sensor that detects the floating of the paper by the predetermined amount or more. The inkjet recording apparatus according to any one of the above items 1) to 5).

(7) When the image is recorded, the control means may receive a collision warning signal from the collision warning sensor when the carriage is located in an area other than the image recording area on the recording medium. The inkjet recording apparatus according to any one of (1) to (6), wherein the movement of the carriage is not stopped.

(8) When recording the image, when the carriage is located in a region not facing the recording medium, the control means may move the carriage even if a collision warning signal is received from the collision warning sensor. The inkjet recording apparatus according to any one of the above (1) to (6), wherein the recording is not stopped.

(9) The control means is arranged so that the leading end of the recording medium conveyed along the second direction reaches one of the two ink jet nozzles located at both ends in the second direction. The ink jet recording apparatus according to any one of the above items (1) to (8), wherein the carriage is not moved.

(10) The collision warning sensor is provided with the second
A plate-shaped detection piece extending between two ink jet nozzles located at both ends in the direction of, and a fixed plate that supports the detection piece rotatably about an axis parallel to the second direction, Elastic holding means for elastically holding the plate-shaped detection piece at a predetermined position (sensor home position); rotation detection means for detecting rotation of the detection piece by a predetermined amount or more;
The inkjet recording apparatus according to any one of the above items (1) to (9), comprising:

(11) The detection piece extends further from the position of the ink jet nozzle on the upstream side in the conveyance direction of the recording medium toward the upstream side from the two ink jet nozzles located at both ends in the second direction. The ink jet recording apparatus according to the above (10), wherein

(12) The detection piece (10) or (1), wherein the detection piece is configured so that its center of gravity substantially coincides with its own rotation center line.
An ink jet recording apparatus according to item 1).

(13) The elastic holding means is an elastic member bridged between the detecting piece and the fixing plate, wherein any of the above (10) to (12) is provided. 2. The ink jet recording apparatus according to claim 1.

(14) The ink jet recording apparatus according to the item (13), wherein the elastic member is a tension coil spring.

(15) The elastic member exerted on the detecting piece by the elastic member is approximately 0.5 g to approximately 10 g, and the elastic member exerts an elastic force of approximately 0.5 g to approximately 10 g.
An ink jet recording apparatus according to item 4).

(16) The ink-jet head according to any one of the above items (1) to (15), wherein the ink-jet head has a plurality of ink-jet heads each having a plurality of ink-jet nozzles. 3. The ink jet recording apparatus according to claim 1.

[0080]

As described above in detail, according to the present invention, at least within the range of movement of the ink jet head, no matter how the recording medium rises from a predetermined position such as on a platen. In addition, the lifting can be detected before the ink jet head collides with the lifting, and the collision of the inkjet head with the lifting of the recording medium can be prevented.

[Brief description of the drawings]

FIG. 1A is a schematic front view of a main part of an ink jet recording apparatus according to an embodiment of the present invention; FIG. 1B is a schematic front view of a main part of the ink jet recording apparatus of FIG. FIG. 2 is a schematic plan view; and (C) shows (A)
FIG. 2 is a schematic right side view of a main part of the inkjet recording apparatus of FIG.

FIG. 2 is an enlarged schematic left side view of a main part of the ink jet recording apparatus of FIG. 1 (A).

FIG. 3 is an enlarged longitudinal sectional view showing a part of an ink jet head contact / separation mechanism of a head holder of a main part of the ink jet recording apparatus of FIG. 1 (A).

FIG. 4A is an enlarged partial plan view showing a state where a collision warning sensor of a main part of the ink jet recording apparatus of FIG. 1A is operated; and FIG. 1
FIG. 3A is an enlarged partial plan view illustrating a state in which the movement of the carriage has stopped immediately after a collision warning sensor of a main part of the inkjet recording apparatus of FIG.

[Explanation of symbols]

10a Inkjet nozzle 10K, 10C, 10M, 10LC, 10LM, 10Y
Inkjet head 14 Head holder 16 Carriage 22 Platen 24 Recording medium 34 Control means 40 Collision warning sensor 44 Rotation center line 46 Detecting piece 48 Elastic holding means 50 Rotation detecting means 52 Rocking piece

Claims (3)

[Claims] An inkjet head having a plurality of inkjet nozzles for ejecting ink; a carriage holding the inkjet head and capable of reciprocating in a first direction parallel to a surface of a recording medium facing the inkjet head; Control means for controlling reciprocal movement of the carriage; provided so as to be located forward of the ink jet head in the movement direction when the carriage is moved, and located at both ends in a second direction intersecting the first direction. An ink jet recording apparatus, comprising: a collision warning sensor for detecting a floating of a predetermined amount or more of a recording medium facing the ink jet head between two ink jet nozzles. 2. The ink jet recording apparatus according to claim 1, wherein the control unit stops the movement of the carriage based on a detection output from the collision warning sensor. 3. An ink jet head having a plurality of ink jet nozzles for ejecting ink; and a head holder holding the ink jet head and capable of reciprocating in a direction perpendicular to a surface of a recording medium facing the ink jet head; A carriage that holds the head holder and that can reciprocate along a first direction parallel to the facing recording medium surface; a control unit that controls the reciprocation of the carriage; The inkjet head is provided on the head holder so as to be located forward of the inkjet head, and the inkjet heads face each other between two inkjet nozzles located at both ends in a second direction crossing the first direction. A collision warning sensor for detecting a floating of a predetermined amount or more of the recording medium. Inkjet recording device.