JP2005238740A - Image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable it to make a non-discharge detecting operation for a recording head 16 stably performed for a long time. <P>SOLUTION: The ink-jet recording device is installed in a carriage 13 so as to make at least a liquid-droplet detection part 31 of a non-discharge detecting device 30 move free back and forth along the sub-scan direction. The detecting device 30 is made move back and forth only inside the carriage 13 by making the liquid-droplet detection part 31 of the device 30 move back and forth toward the sub-scan direction using a non-discharge driving means 27, thereby, regardless of the moving state of the carriage 13 itself, the movement of the non-discharge detecting device 30 is well maintained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet 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.

  As one of output devices of 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 an ink liquid as a recording liquid is provided at appropriate timing from a plurality of ink nozzles provided in the recording head. The droplet is ejected.

  On the other hand, such an ink jet recording apparatus is often provided with non-ejection detecting means for checking whether or not ink droplets are normally ejected from each ink nozzle provided in the recording head. The non-ejection detection means includes, for example, an optical droplet detection unit, and moves the carriage to which the recording head is attached in the main scanning direction so that the ink nozzles of the recording head are positioned immediately above the droplet detection unit. At the same time, ink droplets are ejected from the ink nozzles of the recording head, and at the same time, detection light is emitted from the light emitting elements of the droplet detection unit toward the ink droplets, and the detection light is emitted by the light receiving elements. 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.

  However, in the conventional non-ejection detection means configured to move the carriage in the main scanning direction in this way, the carriage moves due to dirt or the like adhering to the guide rail (shaft) that movably supports the carriage. The speed may fluctuate or become uneven, which may result in inaccurate detection of ink droplets by the non-ejection detection means described above, or it may take time to control the convergence of the stop position and increase the time for non-ejection detection. May cause problems.

  In addition, ink droplets ejected from the recording head float in a mist state and adhere to the light-emitting and light-receiving elements that constitute the droplet detection unit of the non-ejection detection means, thereby causing non-ejection. There is a possibility that the detection sensitivity of the detection means is lowered.

JP2001-171097

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an ink jet recording apparatus that can stably perform a non-ejection detection operation for a recording head over a long period of time.

  In order to achieve the above object, in the ink jet recording apparatus according to claim 1 of the present invention, a recording head having a plurality of ink nozzles arranged in a line along the sub-scanning direction is attached to a carriage, and the recording is performed. A plurality of ink nozzles in the head are appropriately selected based on image formation information, and ink droplets are ejected onto a recording medium transported in the sub-scanning direction. An ink jet recording apparatus that detects the presence or absence of ink droplets ejected from each ink nozzle of a head based on a detection signal output from a droplet detection unit provided in a non-ejection detection unit. The non-ejection detection means is mounted so that at least the droplet detection section can reciprocate along the sub-scanning direction.

  According to the ink jet recording apparatus of the first aspect having such a configuration, since the non-ejection detection means is reciprocated only inside the carriage, the non-ejection detection means moves regardless of the movement state of the carriage itself. It is designed to be well maintained.

  In the ink jet recording apparatus according to a second aspect of the present invention, the non-ejection detection means according to the first aspect reciprocates between a standby position stored in the carriage and a detection position exposed outside the carriage. It is configured as follows.

  According to the ink jet recording apparatus of the second aspect having such a configuration, when the non-ejection detection is not performed, the non-ejection detection means is maintained in the protection state at the standby position stored in the carriage. Adhesion of ink droplets and other dusts ejected from the head is well prevented.

  Furthermore, an ink jet recording apparatus according to a third aspect of the present invention comprises a non-ejection driving means for reciprocating the non-ejection detection means according to the first aspect, wherein the non-ejection detection means moves the recording medium in the sub-scanning direction. A sub-scanning motor for feeding out is provided as a drive source, and an intermittent mechanism is provided to transmit or block the rotational output from the sub-scanning motor side to the droplet detection unit of the non-ejection detection means. ing.

  According to the ink jet recording apparatus of the third aspect having such a configuration, the discharge failure driving means is moved using the already provided sub-scanning motor, and it is necessary to provide a dedicated drive motor or the like. Disappears.

  Furthermore, in the ink jet recording apparatus according to claim 4 of the present invention, the non-ejection detection means in claim 1 includes an optical non-ejection detection mechanism having a light emitting element and a light receiving element. In the ink jet recording apparatus according to claim 5, the optical axis connecting the light emitting element and the light receiving element of the non-ejection detecting means in claim 4 is arranged so as to be substantially orthogonal to the row direction of the plurality of ink nozzles in the recording head, and It is configured to move in the column direction of the ink nozzles. In the ink jet recording apparatus according to claim 6 of the present invention, the optical axis connecting the light emitting element and the light receiving element of the non-ejection detecting means in claim 4 is in the row direction of the plurality of ink nozzles in the recording head. The ink nozzles are arranged at an appropriate angle, and are configured to move in the row direction of the ink nozzles.

  As in the ink jet recording apparatus according to claim 4, claim 5, or claim 6 having such a configuration, the present invention can be satisfactorily applied to various types of optical non-ejection detection means. Is possible.

  As described above, the ink jet recording apparatus according to the first aspect of the invention is capable of reciprocating at least the droplet detection portion of the non-ejection detection means along the sub scanning direction with respect to the carriage reciprocating in the main scanning direction. The non-ejection detection means is reciprocated only within the carriage by moving the droplet detection portion of the non-ejection detection means back and forth in the sub-scanning direction. Since it is configured to maintain good movement of the discharge detection means, it is possible to stably perform the non-discharge detection operation for the recording head over a long period of time, and greatly improve the reliability of the ink jet recording apparatus. Can do.

  According to a second aspect of the present invention, there is provided an ink jet recording apparatus in which the non-ejection detection means according to the first aspect is reciprocated between a standby position stored in the carriage and a detection position exposed outside the carriage. When non-ejection detection is not performed, the non-ejection detection means is protected at the standby position stored in the carriage, and the ink droplets and other dusts ejected from the recording head are prevented well. The effects described above can be further enhanced.

  Furthermore, an ink jet recording apparatus according to a third aspect of the present invention uses, as a drive source, a sub-scanning motor that feeds a recording medium in the sub-scanning direction to the non-ejection driving unit that reciprocates the non-ejection detection unit in the first aspect. And an intermittent mechanism for transmitting or interrupting the rotation output from the sub-scanning motor side to the droplet detection section of the non-ejection detection means is eliminated, thereby eliminating the need for a dedicated drive motor or the like. Therefore, the above-described effects can be reliably obtained with a simple configuration.

  Furthermore, the ink jet recording apparatus according to claim 4 or claim 5 or claim 6 of the present invention can be satisfactorily applied with various structures to the optical non-ejection detection means. In addition to the effects described above, the usefulness of the ink jet recording apparatus can be further enhanced.

  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 using roll paper will be outlined.

  That is, the recording paper P as a recording medium pulled out from a roll body (not shown) is held on the platen 11 of the plotter 10 shown in FIG. P is conveyed in the sub-scanning direction (perpendicular to the paper surface) while being sandwiched between a conveying roller and a pinch roller (not shown) that are rotationally driven by a sub-scanning motor described later.

  Further, a long and narrow scanning rail (guide rail) 12 is suspended above the platen 11 so as to extend in a substantially horizontal direction. A carriage 13 is mounted on the scanning rail 12 so as to be reciprocally movable through a slide bearing portion. The carriage 13 reciprocates in the main scanning direction (left-right direction on the paper surface) according to a scanning belt 15 using a main scanning motor 14 as a drive source. It is made the structure to do.

  A recording head 16 having an ink tank is mounted on the carriage 13. The recording head 16 is configured to reciprocate in the print forming area together with the carriage 13 described above. The recording head 16 is provided with a plurality of ink nozzles as described later in a plurality of rows. Ink droplets are ejected from each of these ink nozzles toward a recording sheet P disposed on the lower side in the figure as a recording medium.

  Such a printing operation (image forming operation) using the recording head 16 corresponds to a control program in the ROM 22 by the CPU 21 in the printing control means 20 as shown in FIG. 2, for example, the flow shown in FIG. The control operation at that time is performed based on the control information stored in the nonvolatile memory 24 while using the RAM 23 as a working memory.

  More specifically, a drive command is issued from the sub-scanning motor control means 26 to the sub-scanning motor 27 in accordance with a command or image data sent from the host side such as another personal computer or workstation to the CPU 21 described above. In accordance with the drive command, the recording roller P is intermittently conveyed by rotationally driving the conveyance roller and the pinch roller described above. On the other hand, the main scanning motor control means 28 issues a drive command whose position is controlled to the main scanning motor 14 based on the position detection signal from the encoder 29, and the driving of the main scanning motor 14 as described above. The main scanning of the recording head 16 is performed. At the same time, an ink nozzle is selected based on the image signal sent to the recording head 16, and ink droplets are ejected from the selected ink nozzle toward the recording paper P. By repeating such a control operation, a desired image is formed.

  Further, the plotter 10 is provided with an undischarge detection device 30 which is an example of an undischarge detection means for detecting the presence or absence of ink droplets discharged from each ink nozzle provided in the recording head 16. Yes. The undischarge detection device 30 according to the present embodiment is attached to the carriage 13 described above, and is configured to reciprocate in the main scanning direction as the carriage 13 moves. In addition, the discharge failure detection device 30 is mounted inside the carriage 13 so as to be reciprocally movable in the sub-scanning direction, and is configured to be reciprocated in the sub-scanning direction by a discharge failure driving means described later. ing.

  In the present embodiment, the discharge failure detection operation by the discharge failure detection device 30 moves the carriage 13 to the side of the platen 11 described above, and the ink absorber 17 (see FIG. 1) disposed outside the printing area. This is performed in a state where the recording head 16 is disposed at the upper position.

  The undischarge detection device 30 in this embodiment includes a known optical droplet detection unit 31 as shown in FIGS. 3 and 4. The schematic structure of the optical droplet detection unit 31 will be described below. On the detection substrate 31a, an LED 31b as a light emitting element and a photodiode 31c as a light receiving element have an appropriate interval in the main scanning direction. The ink droplets ejected from the ink nozzles of the recording head 16 described above pass through the facing interval between the LED 31b and the photodiode 31c. When the inspection light emitted from the LED 31b is blocked by the passage of the ink droplet, an ink droplet detection signal is output from the photodiode 31c through the connector 31d.

  The ink droplet detection signal output from the photodiode 31c is sent to the CPU 21 via the amplification / comparison circuit 32 and the I / O port 33 of the print control means 20 shown in FIG. A so-called recovery operation is performed on the ink nozzle whose state is detected, or a complementary ejection control operation is performed by another ink nozzle. The printing control means 20 at this time may be provided on the apparatus main body side or may be provided so as to be mounted on the carriage 13 described above.

  On the other hand, the optical axis 31e connecting the light emitting element 31b and the light receiving element 31c of the undischarge detection device 30 in the present embodiment has a plurality of inks provided on the recording head 16, as shown in FIG. The nozzle rows 16a, 16b,... Are arranged substantially in parallel along a direction (horizontal direction in FIG. 5) substantially orthogonal to the arrangement direction (vertical direction in FIG. 5), and the ink nozzle rows 16a, 16b. The undischarge detecting device 30 is moved along the arrangement direction of.

  In the present embodiment, the ink nozzle rows 16a, 16b,... Have, for example, six rows (six colors) of cyan, magenta, yellow, black, light cyan, and light magenta. 16a, 16b,... Extend in the paper feed direction (vertical direction in FIG. 5) which is the sub-scanning direction. The number of nozzles in each of the ink nozzle rows 16a, 16b,... At this time is set to “256” in the present embodiment, and a total of 256 nozzles from the first nozzle to the 256th nozzle. Ink nozzles are provided in each nozzle row.

  Note that the same configuration is adopted even in the case where the ink nozzle rows are configured in four rows (four colors) and in which the recording head is provided separately for each color. Further, the optical axis 31e of the discharge failure detection device 30 described above is arranged so as to form an appropriate angle with respect to the arrangement direction of the plurality of ink nozzle rows 16a, 16b,. It is also possible to adopt a configuration in which the discharge detection device 30 is moved along the arrangement direction of the ink nozzle rows 16a, 16b,.

  On the other hand, the undischarge detecting device 30 described above is attached to the carriage 13 via an undischarge driving means 34, and the auxiliary discharge means 34 is driven by the driving force of the undischarge driving means 34 at a lower portion of the carriage 13. It is configured to reciprocate in the scanning direction.

  That is, as particularly shown in FIGS. 6 and 7, a small-diameter non-ejection detection support shaft 34a extends along the main scanning direction at the front portion of the carriage 13 in the sub-scanning direction (paper feeding direction). It is provided to extend. A large-diameter non-ejection detection drive shaft 34b is provided on the rear side portion of the carriage 13 in the sub-scanning direction (paper feeding direction) so as to extend along the main scanning direction. The detection drive shaft 34b is arranged so as to swing in the vertical direction about the non-ejection detection support shaft 34a.

  The non-ejection detection drive shaft 34b is connected to the output shaft of a solenoid 34c disposed immediately above the non-ejection detection drive shaft 34b. The ejection detection drive shaft 34b is swung in the vertical direction. That is, the operation of the solenoid 34c causes the non-ejection detection drive shaft 34b to move to the standby position (see FIG. 7) stored on the inner side of the carriage 13 and the non-ejection detection drive shaft 34b from the inner side of the carriage 13. It is configured to reciprocate in the vertical direction between the detection position (see FIG. 8) where a part (lower part) is exposed to the outside.

  Further, a pair of non-ejection detection drive belts 34d and 34d extending in the sub-scanning direction are spanned between the non-ejection detection support shaft 34a and the non-ejection detection drive shaft 34b. The non-ejection detection drive shaft 34b is rotationally driven, so that both the non-ejection detection drive belts 34d and 34d are driven.

  The pair of non-ejection detection drive belts 34d and 34d are arranged apart from each other in the main scanning direction by an amount corresponding to the interval between the light emitting element 31b and the light receiving element 31c of the optical droplet detecting unit 31 described above. A detection substrate 31a of the optical droplet detection unit 31 is attached between the pair of non-ejection detection drive belts 34d and 34d so as to be spanned in the main scanning direction. Accordingly, as described above, the non-ejection detection drive belts 34d and 34d are driven by the belt so that the entire optical droplet detection unit 31 is reciprocated in the sub-scanning direction.

  On the other hand, the sub-scanning motor 27 described above is disposed at a lower position on the back side in the paper feeding direction with respect to the carriage 13 (see FIG. 8), and a timing belt 27c is provided on the output shaft 27a of the sub-scanning motor 27. The drive roller 27d is connected through the. The drive roller 27d is disposed obliquely below the pair of driven rollers 34e and 34e attached to both end portions in the axial direction of the non-ejection detection drive shaft 34b. As described above, when the non-ejection detection drive shaft 34b swings and the driven rollers 34e and 34e move up and down, the driven rollers 34e and 34e are driven to rotate away from the drive roller 27d. Switching between a standby position (see FIG. 7) where the force is cut off and an inspection position (see FIG. 8) that can be in pressure contact with each other and transmit the rotational driving force is performed. Is configured.

  That is, at the standby position in FIG. 7 in which the above-described non-ejection detection drive shaft 34b and the driven rollers 34e, 34e are swung so as to float upward by the operation of the intermittent mechanism, the non-ejection detection device 30 is a carriage. 13 and the non-ejection detection drive shaft 34b and the non-ejection detection drive belts 34d and 34d are blocked from rotating, whereby the non-ejection detection device 30 is stopped. If the entire discharge failure detection device 30 is stored inside the carriage 13 as described above, the discharge failure detection device 30 is protected from the external environment, and adhesion of ink mist and the like discharged from the recording head 16 is prevented. Is prevented.

  On the other hand, at the inspection position in FIG. 8 where the non-ejection detection drive shaft 34b and the driven rollers 34e, 34e are swung downward, the non-ejection detection device 30 is exposed from the carriage 13 to the lower side. At the same time, the non-ejection detection drive shaft 34b and the non-ejection detection drive belts 34d, 34d are put in a rotational drive state, and as a result, the non-ejection detection device 30 is switched to a state of moving in the sub-scanning direction.

  Here, the carriage 13 is provided with one or more positioning projection plates 13a having an appropriate positional relationship with respect to the ink nozzle rows 16a, 16b,. It is attached so as to protrude downward from the lower end surface side. The positioning projection plate 13a moves from the first nozzle in each of the ink nozzle rows 16a, 16b,... At a predetermined constant speed toward the upstream side in the movement direction of the discharge failure detection device 30. A position that is arranged at a position separated by the area a and crosses the optical axis 31e that connects the light emitting element 31b and the light receiving element 31c when the discharge failure detection device 30 performs inspection movement in the sub-scanning direction as described above. It is arranged to become. And the detection control using the said undischarge detection apparatus 30 in the time of the positioning protrusion board 13a moving the above-mentioned uniform speed movement area | region a at a constant speed from the position which crossed the optical axis 31e of the undischarge detection apparatus 30. Is configured to start.

  Note that the home position (HP) of the undischarge detecting device 30 at that time is further from the arrangement position of the positioning projection plate 13a to the upstream side in the moving direction of the undischarge detecting device 30. It is set at a position separated by the acceleration area required for

Next, an undischarge detection operation using such an undischarge detection device 30 will be specifically described with reference to FIG.
As shown in FIG. 9, when non-ejection detection control is started by the CPU (step 1), first, the carriage 13 is moved to the non-ejection detection position as shown by the arrow in FIG. (Step 2), the recording head 16 is disposed above the ink absorber 17 disposed outside the printing area on the side of the platen 11. If the distance between the recording head 16 and the recording paper P is sufficiently large, the undischarge detection position can be set on the recording paper P only by setting the recording paper P on the platen 11. It can be set at an arbitrary position.

  Next, the discharge failure detection device 30 in the standby position in FIG. 7 is lowered to the detection position in FIG. 8 by operating the solenoid 34c of the discharge failure drive means 34 (step 3). As a result, the driven rollers 34e and 34e of the non-ejection detection drive shaft 34b come into contact with the drive roller 27d, and the rotational driving force from the sub-scanning motor 27 is non-ejection through the drive roller 27d, the driven roller 34e and the non-ejection detection drive shaft 34b. This is transmitted to the detection drive belts 34d, 34d side, and the undischarge detection device 30 is moved in the sub-scanning direction (step 4).

  In moving the discharge failure detection device 30 in the sub-scanning direction, first, the carriage 13 increases the movement speed of the discharge failure detection device 30 until reaching the positioning projection plate 13a, and then reaches a constant speed. The detection device 30 is moved at a fixed speed set appropriately. The undischarge detection device 30 reaches the position of the first nozzle in each of the ink nozzle rows 16a, 16b,... By moving the above-mentioned constant velocity moving region a in the sub-scanning direction. From this point, detection control using the discharge failure detection device 30 is started. Since the constant velocity moving area a at this time is a known distance set in advance, high-accuracy positioning can be easily performed by managing the movement time of the discharge failure detection device 30.

  Next, ink discharge is started from each ink nozzle of the recording head 16 (step 6), and the non-discharge detection device 30 is moved in the sub-scanning direction from the above-described home position (HP) position. Whether or not ink is ejected from the nozzles is confirmed (step 7). More specifically, after a predetermined time after the positioning projection plate 13a is recognized by the discharge failure detection device 30, the first of the ink nozzle rows 16a, 16b,. ) Is ejected from the first (lower end position in FIG. 5) nozzle in the ink nozzle row 16a, and the ejection is confirmed. Next, ejection from the first nozzle in the second ink nozzle row 16b is performed, and the ejection is confirmed. Then, when the discharge from the first nozzle in the sixth (right end position in FIG. 5) ink discharge is performed and the discharge confirmation is completed, the second (second from the left end position in FIG. 5) is completed. The ejection from the second nozzle in the ink nozzle row 16b is performed, and the ejection is confirmed. By repeating this, ejection confirmation up to the 256th nozzle in the sixth (rightmost position in FIG. 5) ink nozzle row 16b is sequentially performed.

  Incidentally, if the discharge frequency of the recording head 16 at that time is 15 KHz, the ink discharge interval is 66.7 μs, and the continuous discharge of each first nozzle in the first to sixth nozzle rows described above. It takes 400 μs. When the nozzle resolution is 600 DPI and the nozzle interval is 42.3 μm, the moving speed of the discharge failure detection device 30 may be set to 105.8 mm / sec.

  With such discharge confirmation, for example, as shown in FIG. 11, the detection signal waveform (as a result of the discharge confirmation) (see FIG. 11A) with respect to the moving speed of the discharge failure detection device 30 described above (see FIG. 11 (b)) is obtained.

  At this time, from when the ink ejected from each ink nozzle of the recording head 16 crosses the optical axis 31e connecting the light emitting element 31b and the light receiving element 31c of the discharge failure detection device 30, the sensor output changes. Since a delay occurs in the sensor response time and the amplifier circuit, the discharge confirmation is performed in consideration of the delay time.

  Further, when the discharge failure detection operation is actually performed by the discharge failure detection device 30, the sub-scanning motor 27 and the like are controlled with reference to the response time t stored in the nonvolatile memory. For example, as shown in FIG. 12, after a time t corresponding to the response time has elapsed from when the discharge trigger signal (see FIG. 12A) becomes active, the output from the comparator over a certain period of time. Monitor whether the signal (see FIG. 12 (b)) has changed (see FIG. 12 (c)), and if no change in the signal is seen, determine that the nozzle is in an undischarged state. The nozzle row and number are stored in the storage element.

  When discharge confirmation for all ink nozzles is completed (step 8 in FIG. 9), the sub-scanning motor 27 is decelerated and stopped (step 9 in FIG. 9). Next, the sub-scanning motor 27 is reversed, the undischarge detection device 30 is returned to the home position (HP) (step 10 in the figure), and the undischarge detection operation using the undischarge detection device 30 is completed. (Step 11).

  Thus, in this embodiment, since the undischarge detection device 30 is reciprocated only within the range of the carriage 13, the undischarge detection device 30 is favorably maintained regardless of the movement state of the carriage 13 itself. It is like that.

  Further, the discharge failure detection device 30 according to the present embodiment is configured to reciprocate between a standby position stored in the carriage 13 and a detection position exposed to the outside of the carriage 13 to detect discharge failure. When it is not performed, the discharge failure detection device 30 is maintained in a protected state at the standby position stored in the carriage 13, and thus adhesion of ink droplets and the like ejected from the recording head 16 is well prevented. .

  Further, the discharge failure driving means 30 in the present embodiment is configured to be detected and moved using a sub-scanning motor 27 that feeds the recording paper P as a recording medium in the sub-scanning direction. There is no need to provide a drive motor or the like, and a simple configuration can be obtained.

  Furthermore, in the present embodiment, the undischarge detection device 30 includes an optical non-discharge detection mechanism having a light emitting element 31b and a light receiving element 31c, and is suitably applied to an optical undischarge detection device. It is possible.

  On the other hand, the embodiment according to FIG. 13 in which the same reference numerals are assigned to the same components as those in the above-described embodiment is a case where the platen roller 41 is used, and the platen roller 41 is an undischarge driving means. It is used as. That is, the driven rollers 42 and 43 for moving the undischarge detection device 30 in the main scanning direction are pressed against the platen roller 41.

  By adopting such a configuration, it is possible to perform the discharge failure detection operation at an arbitrary position in the print area as long as the recording paper P is set on the platen roller 41. Therefore, for example, test printing is performed. It is possible to simultaneously perform the discharge failure detection operation.

  Further, in the embodiment shown in FIG. 14, the optical axis 31 e of the optical droplet detection unit 31 of the discharge failure detection unit 30 is parallel or slightly inclined with respect to the nozzle row of the recording head 16. The undischarge detection means 30 is arranged and moved in a direction substantially orthogonal to the nozzle row of the recording head 16. Also in such an embodiment, the same operation and effect as the above-described embodiment can be obtained.

  The invention made by the inventor has been specifically described based on the embodiment. However, the invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, in the above-described embodiment, the present invention is applied to a plotter, but the present invention is not limited thereto, and is similarly applied to various other ink jet recording apparatuses. It is something that can be done.

  The image forming apparatus according to the present invention described above can be widely applied to a wide variety of ink jet recording apparatuses such as printers as well as ink jet recording apparatuses such as plotters.

It is front explanatory drawing showing the schematic structure of the plotter as an example of the inkjet recording device to which this invention is applied. FIG. 2 is a block diagram illustrating a schematic configuration of a print control device mounted on the plotter illustrated in FIG. 1. FIG. 3 is an enlarged plan view illustrating a droplet detection unit mounted on the undischarge detection device. FIG. 6 is a side elevational view showing an enlarged droplet detection unit mounted on the undischarge detection device. FIG. 2 is a bottom explanatory view showing a recording head portion mounted on the plotter shown in FIG. 1. It is bottom explanatory drawing which represented typically the structure of the undischarge detection apparatus in one Embodiment of this invention from the bottom face side. It is side surface explanatory drawing which represented typically the standby state of the undischarge detection apparatus in one Embodiment of this invention represented by FIG. It is side surface explanatory drawing which represented typically the undischarge detection state of the undischarge detection apparatus in one Embodiment of this invention represented by FIG. It is a flowchart showing an example of the non-discharge detection operation | movement by the non-discharge detection apparatus in one Embodiment of this invention. FIG. 10 is an explanatory plan view schematically illustrating a start operation of a discharge failure detection operation by the discharge failure detection apparatus illustrated in FIG. 9. It is a diagram showing the timing of the non-discharge detection operation | movement by the non-discharge detection apparatus in one Embodiment of this invention. It is a diagram showing an example of processing operation of a discharge failure detection signal in a discharge failure detection device according to an embodiment of the present invention. It is side surface explanatory drawing which represented typically the undischarge detection state of the undischarge detection apparatus in other embodiment of this invention. FIG. 6 is an explanatory bottom view showing a recording head portion in another embodiment of the present invention.

Explanation of symbols

10 Plotter (inkjet recording device)
11 Platen P Recording paper (Recording medium)
DESCRIPTION OF SYMBOLS 13 Carriage 13a Positioning projection board 14 Main scanning motor 16 Recording head 16a, 16b Ink nozzle row 17 Ink absorber 20 Printing control means 27 Sub scanning motor 27c Timing belt 27d Drive roller 30 Undischarge detection device 31 Optical droplet detection part 31a Detection board 31b LED (light emitting element)
31c Photodiode (light receiving element)
31e Optical axis 34 Undischarge drive means 34a Non-discharge detection support shaft (intermittent mechanism)
34b Non-ejection detection drive shaft (intermittent mechanism)
34c Solenoid (intermittent mechanism)
34d Non-ejection detection drive belt 34e Driven roller

Claims (6)

A recording head in which a plurality of ink nozzles are arranged in a row along the sub-scanning direction is attached to the carriage,
A plurality of ink nozzles in the recording head are appropriately selected based on image formation information, and the ink droplets are ejected onto a recording medium conveyed in the sub-scanning direction.
In the inkjet recording apparatus configured to detect the presence or absence of ink droplets ejected from each ink nozzle of the recording head based on a detection signal output from a droplet detection unit provided in the non-ejection detection unit,
An ink jet recording apparatus, wherein at least a droplet detection portion of the non-ejection detection means is attached to the carriage so as to be reciprocally movable along a sub-scanning direction.   The non-ejection detection means is configured to reciprocate at least between a standby position where the droplet detection unit is housed inside the carriage and a detection position exposed to the outside of the carriage. The ink jet recording apparatus according to claim 1. A non-ejection drive unit that reciprocates the non-ejection detection unit, and the non-ejection detection unit includes a sub-scanning motor that feeds the recording medium in a sub-scanning direction as a drive source;
2. The ink jet according to claim 1, wherein an intermittent mechanism is provided to transmit or block the rotational output from the sub-scanning motor side to a droplet detection portion of the non-ejection detection means. Recording device.   The ink jet recording apparatus according to claim 1, wherein the liquid droplet detection unit of the non-ejection detection unit includes an optical non-ejection detection mechanism having a light emitting element and a light receiving element. The optical axis connecting the light emitting element and the light receiving element is arranged so as to be substantially perpendicular to the row direction of the plurality of ink nozzles of the recording head, and the liquid droplet detection unit of the non-ejection detection means is provided on the ink nozzle. The ink jet recording apparatus according to claim 4, wherein the ink jet recording apparatus is configured to move along a column direction. The optical axis connecting the light emitting element and the light receiving element is arranged so as to form an appropriate inclination angle with respect to the row direction of the plurality of ink nozzles of the recording head, and the droplet detection unit of the non-ejection detection means The ink jet recording apparatus according to claim 4, wherein the ink jet recording apparatus is configured to move in a row direction of the ink nozzles.

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