JP2005007809A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely detect non-ejection of a recording head 23 in a simple structure. <P>SOLUTION: A liquid droplet detection section 31 is provided to a non-ejection detecting means 30 for detecting presence or absence of an ink droplet to be ejected from each ink nozzle of the recording head 23. At least one of the liquid droplet detection section 31 and the recording head 23 is disposed to be freely moved toward the other in the vertical direction. A positioning mechanism 38 for maintaining a distance between the liquid droplet detection section 31 of the non-ejection detecting means 30 and the recording head 23 to be in an adequate value is provided thereto. The detection of the non-ejection can be adequately performed irrespective of various conditions such as the vertical position of the recording head 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet recording apparatus that forms an image by ejecting ink droplets from a plurality of ink nozzles provided in a recording head toward a recording medium.
[0002]
[Prior art]
As one of output devices for computers and workstations, an ink jet recording apparatus that forms an image by ejecting ink droplets onto a recording medium such as recording paper is widely used. In this ink jet recording apparatus, a recording head is mounted on a carriage that reciprocates in the main scanning direction, and ink droplets as recording liquid are ejected from a plurality of ink nozzles provided in the recording head at an appropriate timing. The structure is made.
[0003]
On the other hand, such an ink jet recording apparatus is often provided with non-ejection detection means for checking whether or not ink droplets are normally ejected from each ink nozzle of the recording head. This non-ejection detection means is constituted by, for example, an optical system, emits detection light from the light emitting element to the ink droplets ejected from the recording head, and the detection light from the light emitting element is received by the light receiving element. The presence or absence of ink droplets is detected by receiving light. A so-called recovery operation is performed on the ink nozzles for which the non-ejection state has been detected by such non-ejection detection means, or ejection operations are performed so as to be complemented by other ink nozzles.
[0004]
[Problems to be solved by the invention]
However, as the image quality and speed are rapidly increased in recent years, the number of ink nozzles mounted on the recording head increases, and the ejected ink droplets tend to be finer. For this reason, it is becoming difficult to accurately detect the presence or absence of ink droplets by the non-ejection detection means described above. In particular, the recording head moves up and down in accordance with the recording conditions, and the distance from the recording medium is increased. In the configuration that can be changed, there is a possibility that the detection accuracy varies depending on the position of the recording head, or that a detection failure may occur if the distance is large.
[0005]
In view of the above problems, an object of the present invention is to provide an ink jet recording apparatus that can perform non-ejection detection of a recording head with high accuracy with a simple configuration.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in an ink jet recording apparatus according to a first aspect of the present invention, a recording head having a plurality of ink nozzles for discharging ink droplets onto a recording medium, and discharging from each ink nozzle of the recording head. In an ink jet recording apparatus comprising a non-ejection detection means for detecting the presence or absence of an ink droplet, the non-ejection detection means and at least one of the recording head is attached to be freely movable so as to be close to or away from the other In addition, a positioning mechanism is provided for holding the distance between the non-ejection detection means and the recording head at an appropriate amount.
[0007]
According to the ink jet recording apparatus according to claim 1 having such a configuration, the distance between the recording head and the non-ejection detection unit is directly and always held at a constant appropriate amount by the positioning mechanism, Non-ejection detection is performed well regardless of other various conditions.
[0008]
In the ink jet recording apparatus according to claim 2 of the present invention, the non-ejection detection means according to claim 1 emits detection light to the ink droplet ejected from the recording head, and the light emitting element. According to the ink jet recording apparatus of the second aspect, the light emitting element and the light receiving element are provided. The liquid droplet detecting unit includes a light receiving element arranged to receive the detection light from the light receiving element. In the non-ejection detection means provided with the droplet detection unit having the above, the action and effect can be obtained effectively.
[0009]
Further, in the ink jet recording apparatus according to a third aspect of the present invention, the positioning mechanism according to the first aspect includes a biasing member that presses the non-ejection detecting means to the recording head side, and a non-ejection detection that is pressed to the recording head side. And a guide member that guides and holds the means at a predetermined position with respect to the face surface of the recording head. Further, in the ink jet recording apparatus according to claim 4 of the present invention, the guide according to claim 3 is provided. The member includes a rail portion and a rail groove portion slidably provided between the recording head side and the non-ejection detection means side.
[0010]
According to the ink jet recording apparatus of the third or fourth aspect having such a configuration, a reliable operation and effect can be obtained by a positioning mechanism having a very simple configuration.
[0011]
On the other hand, in the ink jet recording apparatus according to claim 5 of the present invention, the rail portion in claim 4 is attached to a head holder that holds the recording head, and the ink jet recording according to claim 5 having such a configuration. According to the apparatus, the rail portion is easily and accurately provided to the recording head via the head holder.
[0012]
In the ink jet recording apparatus according to claim 6 of the present invention, the recording head according to claim 1 can change the distance from the recording medium by moving up and down in accordance with the recording conditions. Has been made.
[0013]
According to the ink jet recording apparatus of the sixth aspect having such a configuration, when the recording head moves up and down, the recording head is located between the recording head and the non-ejection detection unit regardless of the position. This distance is directly held at a constant appropriate amount by the positioning mechanism, so that non-ejection detection can be performed satisfactorily regardless of the position change of the recording head.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Prior to that, the overall structure of a plotter as an ink jet recording apparatus will be outlined.
[0015]
In other words, on the platen 12 of the plotter 10 shown in FIG. 1, recording is performed as a recording medium that is sandwiched between the conveying roller 13 and the pinch roller 14 and conveyed in the arrow X direction (sub-scanning direction). The paper P is configured to be placed thereon, and a scanning rail (guide rail) 15 extending in a substantially horizontal direction is stretched over a position above the platen 12. A carriage 16 is reciprocally mounted on the scanning rail 15 via a slide bearing, and is reciprocated in the arrow Y direction (main scanning direction) by a belt 17 using a motor (not shown) as a drive source. Thus, it is configured to scan.
[0016]
In addition, a recording head 23 including an ink tank 22 is mounted on the carriage 16 via a head holder 21 formed in a frame shape. The recording head 23 is configured to reciprocate in the print forming area together with the carriage 16, and the recording head 23 is provided with a number of ink nozzles (not shown). Ink droplets are ejected from the nozzle toward the recording paper P as a recording medium on the lower side in the figure.
[0017]
Then, the recording paper P is intermittently transported by the transport roller 13 and the pinch roller 14 according to image data sent from another personal computer or work station (not shown), and the recording head 23. Ink droplets are ejected from the ink nozzle selected based on the image signal sent to the recording head 23 toward the recording paper P, and a desired image is formed by repeating this scanning. It has become so.
[0018]
At this time, as shown in FIGS. 2 and 3, the recording head 23 described above is moved up and down in, for example, three stages by rotating the head lever 24 provided on the upper side of the head holder 21. Thus, the distance from the recording paper P can be changed according to various recording conditions such as the type of recording medium to be used. Since the recording head position adjusting structure using the head lever 24 has a well-known structure, a detailed description thereof will be omitted.
[0019]
Returning to FIG. 1 again, the non-ejection detection means 30 and the recovery device 40 are respectively arranged on the side of the recording paper P, that is, outside the print image area. Of these, the recovery device 40 performs the above-described recording head 23 at an appropriate timing such as before the start of printing when a predetermined amount of printing is performed, when a predetermined time has elapsed, or when designated by the user. It is configured to absorb ink from the ink nozzles or to wipe the face surface. Since the recovery device 40 also has a known configuration, a detailed description thereof will be omitted.
[0020]
On the other hand, the non-ejection detection means 30 has a configuration for detecting the presence / absence of ink droplets ejected from the ink nozzles of the recording head 23, and particularly as shown in FIGS. A known droplet detection unit 31 is provided. The schematic structure of the droplet detection unit 31 will be described. An LED 31b as a light emitting element and a photodiode 31c as a light receiving element are appropriately arranged in the sub-scanning direction (X direction) on the detection substrate 31a. The LED 31b and the photodiode 31c are arranged so as to oppose each other with a space therebetween, and are arranged so that the ink droplets ejected from the ink nozzles of the recording head 23 pass through the facing interval portion between the LED 31b and the photodiode 31c. Yes. When the inspection light emitted from the LED 31b is blocked by the passage of the ink droplet, a detection signal is output from the photodiode 31c, and the detection signal is sent to the main body control unit (not shown) through the connector 31d. It is supposed to be sent.
[0021]
Here, the droplet detection unit 31 of the non-ejection detection means 30 described above is attached to the recording head 23 so as to be freely movable so as to approach and separate from the recording head 23. That is, in addition to FIG. 2 and FIG. 3 described above, as shown in FIG. 6, a pair of fixed bearing plates 33 and 33 are formed on the frame substrate 32 on the main body side formed in a flat plate shape. It is arranged so as to face the scanning direction (X direction) at an appropriate interval, and the first support shaft 34 is rotatably spanned between both the bearing plates 33, 33, and A second support shaft 36 is rotatably attached to the first support shaft 34 via link plates 35 and 35. Further, the second support shaft 36 is attached with bearing plates 37a, 37a provided at one end edge portion of the holder plate 37, and the holder plate 37 is integrally formed with the bearing plates 37a, 37a. The second support shaft 36 is pivoted in the vertical direction.
[0022]
Furthermore, on the upper surface side of the holder plate 37, the above-described droplet detection unit 31 is fixed so as to be placed thereon. In other words, the droplet detection unit 31 fixed on the holder plate 37 can freely translate in the height direction via the link mechanisms 33, 34, 35, 36 to the frame substrate 32 on the main body side. It is configured as follows. The droplet detection unit 31 on the holder plate 37 configured to be freely parallel movable in the height direction as described above is applied to the recording head 23 by an urging member and a guide member that constitute a positioning mechanism 38 as described below. On the other hand, it is guided and held at a predetermined position, and the distance between the droplet detection unit 31 and the face surface of the recording head 23 is always held at an appropriate amount.
[0023]
That is, the positioning mechanism 38 is an urging member that is mounted in a compressed state between the end portion on the rotating side (right side in FIG. 2) of the holder plate 37 and the frame substrate 32 on the main body side. The coil spring 38a is provided, and the holder plate 37, that is, the entirety of the droplet detection unit 31, is pushed upward toward the recording head 23 side by a pressing force upward of the coil spring 38a. .
[0024]
Further, on the upper surface side of the holder plate 37, a pair of rail groove portions 38b, 38b constituting one side of the guide member are arranged to face each other with an appropriate distance in the main scanning direction (X direction). Each of these rail groove portions 38b, 38b is formed from a substantially rectangular parallelepiped block member attached so as to protrude upward. On the upper surface side of each of these rail groove portions 38b, 38b, the main scanning direction ( Concave grooves 38c, 38c extending substantially parallel to each other in the Y direction) are formed. In each of the concave grooves 38c, 38c, the edge portions of the rail portions 38d, 38d provided on the recording head 23 side so as to constitute the other side of the guide member are brought into contact.
[0025]
That is, on the lower surface side of the head holder 21 holding the recording head 23, a pair of rail portions 38d, 38d made of a thin plate member are separated by an appropriate distance in the sub-scanning direction (X direction) and substantially parallel. Opposed. The convex edge 38e forming the lower edge of each of the rail portions 38d is disposed so as to be at substantially the same height as the face surface 23a provided on the lower end surface of the recording head 23. The lower edge side convex edge 38e of each rail portion 38d and the concave groove 38c of each rail groove portion 38b described above are in the main scanning direction (Y direction) as shown in FIG. Are separated from each other.
[0026]
At this time, a guide convex edge 38f that continuously slopes upward is connected to the front end side and the rear end side (left end side and right end side in FIG. 2) with respect to the lower end side convex edge 38e of each rail portion 38d. Has been. When the recording head 23 moves in the direction of arrow A in FIG. 2 (the left direction in the figure) in order to perform the above-described undischarge detection, the guide convex edge 38f of each rail portion 38d becomes the rail groove portion 38b. The rail groove portions 38b are pushed downward by the guide convex edges 38f.
[0027]
After each rail groove 38b, that is, the holder plate 37 is pushed down in this way, as shown in FIG. 7, the lower edge side convex edge 38e of each rail 38d is formed on each rail groove 38b. It enters into and comes into contact with the concave groove 38c. In this abutting state, the face surface 23a on the recording head 23 side and the droplet detection unit 31 attached on the holder plate 37 side have the height of each rail portion 38d and the depth of the rail groove portion 38b. It is held in a state separated by a certain distance determined by this. That is, by appropriately setting the height of each rail portion 38d or the depth of each rail groove portion 38b, the positional relationship between the face surface 23a of the recording head 23 and the droplet detection unit 31 is always in an appropriate state. Will be held.
[0028]
As described above, in this embodiment, the distance between the face surface 23 a of the recording head 23 and the droplet detection unit 31 of the non-ejection detection unit 30 is directly and appropriately adjusted by the guide member constituting the positioning mechanism 38. Therefore, the non-ejection detection is always performed satisfactorily regardless of various other conditions such as the height position of the recording head 23.
[0029]
Further, the droplet detection unit 31 in the present embodiment includes a light emitting element 31b and a light receiving element 31c, and the non-ejection including the droplet detection unit 31 having such a light emitting element 31b and the light receiving element 31c. In the detection means 30, an action and an effect are obtained effectively.
[0030]
Further, the positioning mechanism 38 in the present embodiment uses a coil spring 38 a as a biasing member that presses the droplet detection unit 31 as the non-ejection detection means 30 toward the recording head 23, and a guide member of the positioning mechanism 38. Is composed of a rail portion 38d and a rail groove portion 38b that are slidable with respect to each other, and the liquid as non-ejection detection means 30 that is pressed toward the recording head 23 by the guide member of such a positioning mechanism 38. Since the droplet detection unit 31 is guided and held at a predetermined position with respect to the face surface 23a of the recording head 23, a reliable operation and effect can be obtained with an extremely simple configuration.
[0031]
In addition, in this embodiment, since the rail portions 38d and 38d constituting the guide member of the positioning mechanism 38 are provided in the head holder 21 that holds the recording head 23, the rail portions 38d and 38d, 38d is provided easily and with high accuracy.
[0032]
Further, the recording head 23 in the present embodiment is configured to move up and down so that the distance from the recording paper P as a recording medium can be changed according to the recording conditions. Regardless of the position of the upper and lower portions 23, the distance between the recording head 23 and the droplet detection unit 31 as the non-ejection detection means 30 is directly set to a constant appropriate amount by the positioning mechanism 38 described above. The non-ejection detection is satisfactorily performed regardless of the position of the recording head 23.
[0033]
On the other hand, in the embodiment shown in FIG. 8 and FIG. 9, three support pins 41, 42, 43 are erected on the frame substrate 32 on the main body side, and each of these support pins 41, Each of the three mounting holes penetratingly formed in the holder plate 44 that holds the droplet detection unit 31 is inserted in a loose-fitting state with respect to 42 and 43, whereby the liquid on the holder plate 37 is The droplet detection unit 31 is configured to be freely movable in the height direction.
[0034]
Further, the urging member constituting the positioning mechanism of the droplet detecting unit 31 on the holder plate 44 configured to be freely parallel movable in the height direction is attached to each of the support pins 41, 42, and 43 described above. The coil springs 45, 46, and 47 are configured. Further, the rail groove portions 48b and 48b constituting the guide member basically have the same configuration as that of the above-described embodiment, but the concave groove 48c provided in each of the rail groove portions 48b and 48b. , 48c is formed to have a width that expands toward the recording head 23 side (one end side in FIG. 8).
[0035]
This corresponds to the gaps between the support pins 41, 42, 43 and the mounting holes described above, and the holder plate 44 is rattled in the width direction due to the gaps between these members. However, the lower edge portion of each rail portion 48d provided on the recording head 23 side is guided by the enlarged portion of the concave groove 48c provided in each rail groove portion 48b, and stably in each concave groove 48c. It has been introduced.
[0036]
The invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0037]
For example, in the embodiment described above, the droplet detection unit 31 of the non-ejection detection unit 30 is provided so as to be freely movable in the height direction with respect to the recording head 23, but the recording head 23 side or both are directed toward the other side. It is also possible to configure so as to be freely movable.
[0038]
In the above-described embodiment, the present invention is applied to a plotter. However, the present invention is not limited thereto, and can be similarly applied to various other ink jet recording apparatuses. It can be done.
[0039]
【The invention's effect】
As described above, in the ink jet recording apparatus according to the first aspect of the present invention, the distance between the non-ejection detecting means for detecting the presence or absence of ink droplets ejected from each ink nozzle of the recording head and the recording head is set. By providing a positioning mechanism that keeps the proper amount at all times, it is configured to perform non-ejection detection well regardless of various conditions such as the height position of the recording head. A simple configuration can be performed with high accuracy, and the reliability of the ink jet recording apparatus can be greatly improved.
[0040]
Further, in the ink jet recording apparatus according to claim 2 of the present invention, since the non-ejection detection means in claim 1 has a droplet detection unit including a light emitting element and a light receiving element, such a light emitting element. The above-described effects can be obtained in the non-ejection detection means including the droplet detection unit having the light receiving element.
[0041]
Furthermore, in an ink jet recording apparatus according to a third aspect of the present invention, the positioning mechanism according to the first aspect includes an urging member that presses the non-ejection detection means to the recording head side, and the non-ejection detection that is pressed to the recording head side. And a guide member that guides and holds the means at a predetermined position with respect to the face surface of the recording head, and the ink jet recording apparatus according to claim 4 of the present invention is the above claim. 3 is provided with a rail portion and a rail groove portion slidably provided between the recording head side and the non-ejection detection means side, thereby providing a positioning mechanism having an extremely simple configuration. Therefore, the effects described above can be obtained easily and reliably.
[0042]
On the other hand, in the ink jet recording apparatus according to claim 5 of the present invention, the rail portion according to claim 4 is attached to a head holder that holds the recording head, so that the rail portion has the head holder with respect to the recording head. Therefore, the effects described above can be obtained with certainty.
[0043]
According to a sixth aspect of the present invention, there is provided an ink jet recording apparatus, wherein the recording head according to any one of the first to fifth aspects moves vertically with respect to the recording medium in accordance with a recording condition. The distance can be changed, and the distance between the recording head and the non-ejection detection means is always kept at a fixed and appropriate amount directly by the positioning mechanism, regardless of whether the recording head is in the vertical movement position. In addition, the above-described effects can be further enhanced because the non-ejection detection is performed satisfactorily regardless of the position change of the recording head.
[Brief description of the drawings]
FIG. 1 is an external perspective view illustrating a schematic structure of a plotter as an example of an ink jet recording apparatus to which the present invention is applied.
FIG. 2 is an enlarged front explanatory view showing a recording head portion mounted on the plotter shown in FIG. 1;
3 is an enlarged side view illustrating a recording head portion mounted on the plotter illustrated in FIG. 1. FIG.
FIG. 4 is an enlarged plan view showing a droplet detection unit mounted on a non-ejection detection unit in an enlarged manner.
FIG. 5 is an enlarged side view illustrating a droplet detection unit mounted on a non-ejection detection unit.
6 is an external perspective explanatory view showing a part of the positioning mechanism of the droplet detection unit shown in FIGS. 4 and 5. FIG.
FIG. 7 is an explanatory front view showing an enlarged view of a recording head portion when the recording head is in a non-ejection detection state.
FIG. 8 is an external perspective explanatory view showing a part of a positioning mechanism of a droplet detection unit according to another embodiment of the present invention.
FIG. 9 is an enlarged side view illustrating a recording head portion when the droplet detection unit positioning mechanism shown in FIG. 8 is provided.
[Explanation of symbols]
10 Plotter (inkjet recording device)
P Recording paper 21 Head holder 23 Recording head 23a Face surface 24 Head lever 30 Non-ejection detection means 31 Droplet detection unit 31a Detection substrate 31b LED (light emitting element)
31c Photodiode (light receiving element)
32 Main body side frame substrate 33, 34, 35, 36 Link mechanism 37 Holder plate 38 Positioning mechanism 38a Coil spring (biasing member)
38b Rail groove (guide member)
38c Concave groove 38d Rail part (guide member)
38e Lower edge side convex edge 38f Guide convex edge 41, 42, 43 Support pin 44 Holder plate 45, 46, 47 Coil spring (biasing member)
48b Rail groove (guide member)
48c groove

Claims (6)

A recording head having a plurality of ink nozzles for discharging ink droplets on a recording medium;
Non-ejection detection means for detecting the presence or absence of ink droplets ejected from each ink nozzle of the recording head;
In an inkjet recording apparatus comprising:
At least one of the non-ejection detection means and the recording head is attached so as to be freely movable so as to approach and separate from the other,
An ink jet recording apparatus, comprising: a positioning mechanism for maintaining an appropriate distance between the non-ejection detecting means and the recording head. The non-ejection detection means includes a light emitting element that emits detection light to the ink liquid droplet ejected from the recording head, and a liquid droplet that includes a light receiving element arranged to receive the detection light from the light emitting element. The inkjet recording apparatus according to claim 1, further comprising a detection unit. The positioning mechanism includes a biasing member that presses the non-ejection detection means toward the recording head,
And a guide member for guiding and holding the non-ejection detection means pressed to the recording head side to a predetermined position with respect to the face surface of the recording head. The inkjet recording apparatus according to 1. 4. The ink jet recording apparatus according to claim 3, wherein the guide member includes a rail portion and a rail groove portion slidably provided between the recording head side and the non-ejection detecting means side. The inkjet recording apparatus according to claim 4, wherein the rail portion is attached to a head holder that holds the recording head. 6. The structure according to claim 1, wherein the recording head is configured to be able to change a distance from the recording medium by moving up and down in accordance with recording conditions. 2. An ink jet recording apparatus according to 1.

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