JP2010064402A - Discharge detecting device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of light emitting elements and the number of light receiving elements, and to highly accurately detect discharging. <P>SOLUTION: Light collimated through a collimator lens 22 from the light emitting element 21 aligns its optical path 25 against second mirrors 41-44 with respect to each turn table so as to correspond to each head and nozzle train by selecting the reflecting angle of a mirror 23 with a turn table 24. The second mirror with the turn table intersects its optical path 25 with the flying passage of ink droplets discharged from each nozzle by aligning the optical path 25 against immediately beneath the nozzle and against the corresponding one among the light receiving elements 31-34, resulting in making the detection of a discharged state and a non-discharged state possible by whether light interrupted by the ink droplets or not. Accordingly, the selection of the second mirrors 41-44 with each turn table or each nozzle train by the optical path 25 becomes possible according to the reflecting angle of the mirror 23, thus enabling to detect each nozzle train by a single LD (light emitting element) 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ejection detection apparatus and an image forming apparatus that detect abnormal ejection of ink using an optical sensor.

  2. Description of the Related Art Conventionally, in an image forming apparatus having an optical discharge detection mechanism using a light emitting element and a light receiving element, it is necessary to provide a pair of light emitting element and light receiving element for each recording element array (for example, nozzle array). It was necessary to accurately match the nozzle position.

  Thus, for example, Patent Document 1 describes a method in which a plurality of light paths are generated using a plurality of light reflecting means, and a head is operated in accordance with the light paths to perform detection. Patent Document 2 describes a method of generating an optical path surface by two or more reflections using two light reflecting means and detecting the optical path surface. Further, Patent Document 3 describes a method of detecting light even when the length of a recording element array (for example, nozzle array) is varied by providing a light reflecting means on the opposite side of the light emitting and light receiving elements.

Patent Document 4 describes a method for adjusting the drive current of a light emitting element so as to keep detection accuracy constant. Patent Document 5 describes a method required for a light receiving element when an ejection port or an ink droplet is small. Describes a method of detecting nozzle non-ejection by irradiating light.
JP 2006-7446 A JP 2004-291475 A JP 2007-152882 A JP 2006-187981 A JP 2006-159842 A

  However, in each of the above methods, the light-emitting element, the light-receiving element, and the light reflecting means are fixed, and if the optical axis is deviated, any method cannot be detected. .

  Patent Document 4 is a method of adjusting the drive current of the light emitting element so as to keep the detection accuracy constant. However, it varies depending on aging of the light emitting element, temperature change, and noise on the optical path (for example, dust). Can only prevent. Further, since the light emitting element and the light receiving element are in the vicinity of the recording element, it is necessary to newly add a shielding plate so as to protect against mist generated during printing.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of reducing the number of light emitting elements and light receiving elements and capable of performing ejection detection with high accuracy. .

  In order to solve the above-described problem, an ejection detection apparatus according to the present invention includes a plurality of recording units having recording elements that eject ink, a light emitting unit that emits a light beam, and a light beam emitted from the light emitting unit. And a plurality of first light beams that advance the light beam parallel to the longitudinal direction vertically below the plurality of recording means by changing the incident angle of the light beam that is rotated and incident. The second light reflection that causes the light beam to be incident on one of the first light reflecting means by changing the incident angle of the collimated light beam to the reflecting means and the condensing means that is rotated and incident. Means and one or more light receiving means for receiving the light beam.

  The first light reflecting means is characterized in that the light reflecting surface is directed in the opposite direction with respect to the recording means so as not to be affected by the mist generated from the recording element when ejection is not detected.

  A plurality of first light reflecting means is provided at a facing position across a plurality of recording means, and the incident light is reflected by any of the first light reflecting means and rotated to change the incident angle. Thus, a third light reflecting means for making the light beam incident on the light receiving means is provided.

  The third light reflecting means is characterized in that the light reflecting surface is directed in the opposite direction with respect to the recording means so as not to be affected by the mist generated from the recording element when ejection is not detected.

  The light reflecting means performs a rotating operation immediately before the ejection detection sequence of the recording means.

  In addition, an image forming apparatus according to the present invention includes any one of the above-described ejection detection devices.

  According to the present invention, it is possible to reduce the quantity of light emitting elements and light receiving elements and to perform discharge detection with high accuracy by providing light reflecting means for rotational control.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus. The image forming apparatus includes a document reading apparatus 102 having an automatic document feeder (ADF) 101 and an image forming apparatus main body 103 having a paper feed tray.

  In the document reading operation, a document set on the document table 104 of the ADF 101 or the document reading glass 105 of the scanner 102 is irradiated with light by a lamp 106, and the reflected signal is transmitted to a CCD (Charge Couppled Device) or CIS (Contact Image). Sensor).

  The read signal is converted into a digital signal by a device called AFE (Analog Front End) and transmitted to a controller (not shown) on the scanner or printer side. The transmitted scan signal (image data) is converted into printer image data by image processing by a controller, and transmitted to a PC (display), a printer engine (not shown), or the like. In the case of inkjet, the printer engine performs rendering processing (processing that replaces image data in the order of head transfer).

  In the printing operation on the paper, the printing paper 114 discharged from the paper feed tray 112 is sent to the paper conveyance belt 110, the printing paper is detected by the paper edge sensor 109, and the carriage 108 equipped with the head starts printing. When moved to the position, the print data subjected to the rendering process is transferred to the head and printing is started. After the printing is completed, the printing paper is discharged to the paper discharge tray 111.

  First, an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIG. 2 and FIG. 2 is a schematic three-dimensional view of the main part of the apparatus, and FIG. 3 is a schematic three-dimensional view of the main part showing the detection part of the discharge detection mechanism.

  The ink jet printer (image forming apparatus) includes heads (recording units) 11 to 14. The heads (recording means) 11 to 14 all have the same configuration, and a plurality of inks (printing colorants) 2 that eject ink (printing colorant) 2 onto a sheet (recording medium) 1 like the head 13 shown in FIG. A recording element (nozzle) 3 is provided.

  In addition, a discharge detection mechanism that detects the discharge state of the recording element (nozzle) 3 is provided. The discharge detection mechanism includes an LD (light emitting element) 21, a collimator lens 22, a mirror (light reflecting means) 23, a turntable (rotating means) 24, and a second mirror (light reflecting means) 41 with a turntable. 44 and PDs (light receiving elements) 31 to 34, and discharge failure is detected by a change in the output of a photosensor which is a light receiving element.

  Hereinafter, the discharge detection mechanism in the embodiment of the present invention will be described in detail.

  The light emitted from the LD (light emitting element) 21 is collimated by the collimating lens 22, and the reflection angle of the mirror (light reflecting means) 23 is selected by the turntable (rotating means) 24. The optical path 25 can be aligned with the second mirrors with a turntable (light reflecting means) 41 to 44 corresponding to the above.

  The second mirrors (light reflecting means) 41 to 44 with the turntable fly the ink droplets 2 ejected from the respective nozzles by aligning the optical path 25 directly below the nozzles and corresponding PDs (light receiving elements) 31 to 34. The ejection state and the non-ejection state can be detected based on whether or not the path 4 and the optical path 25 intersect and is blocked by the ink droplet 2.

  According to the said structure, according to the reflection angle of the mirror (light reflection means) 23, it is possible to select the 2nd mirrors (light reflection means) 41-44 with a turntable, ie, each nozzle row, according to the reflection angle, Each nozzle row can be detected by one LD (light emitting element) 21.

  Further, as shown in FIG. 4, by similarly arranging a mirror with a turntable on the PD (light receiving element) 31 to 34 side, the PD (light receiving element) 35 can be combined. FIG. 4 is a schematic three-dimensional view of the main part of the apparatus.

  In FIG. 4, third mirrors (light reflecting means) 51 to 54 with turntables are provided instead of the PDs (light receiving elements) 31 to 34 shown in FIG. 2, and the light is condensed on the PD (light receiving element) 35. (Light receiving element) 35 can be made one.

  In this way, by providing one or more mirrors (light reflecting means) 23 and the like so as to connect the LD (light emitting element) 21 and the PD (light receiving element) 35 with the optical path 25, the LD (light emitting element) 21 and the PD ( It is possible to reduce the number of light receiving elements) 35 and to separate them from the heads (recording means) 11 to 14, and thus prevent contamination due to mist generated from the heads (recording means) 11 to 14 during printing. It becomes possible to do.

  However, compared with LD (light emitting element) 21, PD (light receiving element) 35 and mirror (light reflecting means) 23, mirrors (light reflecting means) 41 to 44 and 51 to 54 are in the vicinity of heads (recording means) 11 to 14. Contamination due to mist is a concern.

  A method for preventing this will be described in detail with reference to a schematic plan view of an essential part showing a mirror (light reflecting means) 41 (42, 43, 44) portion of the discharge detection mechanism shown in FIGS. FIG. 5 is a schematic plan view of the main part of a mirror (light reflecting means) 41 (42, 43, 44) during ejection detection, and FIG. 6 is a mirror (light reflecting means) 41 during printing (other than ejection detection). (42, 43, 44) The main part schematic plan view is shown.

  In FIG. 5, a mirror (light reflecting means) 43 (41, 42, 44) has a double-sided configuration of a reflective surface 61 and a non-reflective surface 62, and is open from the inner wall 71 when detecting ejection. Thus, the optical path 25 goes in the direction of the head 13 (11, 12, 14).

  FIG. 6 shows the non-detection state, and the mirror (light reflecting means) 43 (41, 42, 44) directs the non-reflecting surface 62 toward the head 13 (11, 12, 14). The reflective surface 61 is protected. Similarly, the mirror (light reflecting means) 51 (52, 53, 54) can also be selected, and the same configuration is applied to the mirrors (light reflecting means) 41 to 44 and 51 to 54 with turntables. Can be considered.

  FIG. 7 is a block diagram showing a main part configuration including an electrical circuit of the discharge detection mechanism. Here, the operation of each block will be described with reference to FIG.

  Heads (recording means) 11 to 14 are mounted side by side for each color (for example, Y, M, C, K). A large number of recording elements (nozzles) 3 are arranged on the lower surface of each head (recording means) 11 to 14, and the heads (recording means) 11 to 14 are arranged so that the nozzle rows are parallel to each other. Has been. This is called a carriage, and the drive circuit 81 is driven by the output of the controller (CPU) 101 at a timing when the carriage and the paper (recording medium) 1 are moved by a moving means (not shown) controlled by the controller (CPU) 101. ˜84 are controlled, and the ink (printing colorant) 2 in the form of fine droplets is ejected from the recording elements (nozzles) 3 of the heads (recording means) 11 to 14 at predetermined timings, respectively. Recording medium) A desired image is recorded on 1.

  The LD (light emitting element) 21 emits light which is a means for detecting the ejection state of each recording element (nozzle) 3. The LD (light emitting element) 21 is controlled to be turned on / off by a controller (CPU) 101. The collimating lens 22 generates an optical path 25 in which the light emitted from the LD (light emitting element) 21 is converted into a parallel light flux and directs it in the direction of the mirror (light reflecting means) 23.

  The mirror (light reflecting means) 23 is rotated by a turntable (rotating means) 24, the rotation of which is controlled by a controller (CPU) 101, and mirrors (lights) corresponding to heads (recording means) 11 to 14 for detecting ejection. (Reflecting means) 41A to 44A are selected and the optical path 25 is directed. The mirror (light reflecting means) 23 is preferably capable of reflecting incident light without attenuation.

  The mirrors (light reflecting means) 41A to 44A are connected to turntables (rotating means) 41B to 44B that can be controlled by the controller (CPU) 101, respectively, and control their rotation angles. Further, any one of the mirrors (light reflecting means) 41A to 44A has the optical path 25 selected by the mirror (light reflecting means) 23, and the recording elements (nozzles) of the heads (recording means) 11 to 14 that perform corresponding ejection detection. ) The rotation angle is controlled by the controller (CPU) 101 so as to go to 3. Similarly, it is desirable that the mirrors (light reflecting means) 41A to 44A can reflect incident light without attenuation.

  The mirrors (light reflecting means) 51A to 54A are connected to turntables (rotating means) 51B to 54B that can be controlled by the controller (CPU) 101, respectively, and control their rotation angles. In addition, there is an optical path 25 in any of mirrors (light reflecting means) 51A to 54A corresponding to heads (recording means) 11 to 14 for detecting ejection, and the rotation angle is controlled by a controller (CPU) 101, and PD (light receiving) The optical path 25 is aligned with the (element) 35. Similarly, it is desirable that the mirrors (light reflecting means) 41A to 44A can reflect incident light without attenuation.

  The PD (light receiving element) 35 is a light receiving element made of a photodiode (or phototransistor), and receives the light in the optical path 25 emitted from the LD (light emitting element) 21. A change in the amount of light received by the PD (light receiving element) 35 is detected by the detection circuit 91 and fed back to the controller (CPU).

  Here, three mirrors (reflecting means) 23, 41A (42A, 43A, 44A), 51A (52A, 53A, 54A) are arranged on the optical path of the optical path 25, and the mirror (reflecting means) 41A (42A). , 43A, 44A) to the mirror (reflecting means) 51A (52A, 53A, 54A), a large number of recording elements (nozzles) 3 arranged on the lower surface of the head (recording means) 11 (12, 13, 14). The mirrors (reflecting means) 23, 41A (42A, 43A, 44A), 51A (52A, 53A, 54A) are controlled so as to be parallel to the nozzle rows of the first and second nozzles. Thereby, it intersects with the flight path 4 of the ink droplet ejected from the recording element (nozzle) 3 and changes whether or not the optical path 25 is shielded depending on the presence or absence of ejection, and the light reception of the PD (light receiving element) 35 accordingly. The amount changes.

  This change can be detected by the detection circuit 91, and is fed back to the controller (CPU) to determine whether the ejection is normal or abnormal by comparing with the controlled drive circuits 81 to 84. Whether the recording element (nozzle) 3 ejects normally or the recording element (nozzle) 3 ejects abnormally is stored in the storage element 102, and the control method for printing or maintenance of the recording element (nozzle) 3 is changed. To do.

  Next, the timing for operating the mirror (light reflecting means) will be described with reference to the flowchart showing the discharge detection flow of FIG. When the image forming apparatus performs ejection detection, it can be detected with high accuracy by performing the following sequence.

  First, the LD (light emitting element) 21 is driven (step S1). In order to select the head (recording means) 11 (12, 13, 14) (or nozzle row) to be detected, the mirror (light reflecting means) 23 is rotated (step S2).

  The optical path 25 is directed in the direction of the recording element (nozzle) 3 that rotates and detects one of the mirrors (light reflecting means) 41 (42, 43, 44) corresponding to the rotation (selection) of the mirror (light reflecting means) 23. (Step S3).

  One of the mirrors (light reflecting means) 51 (52, 53, 54) corresponding to the rotation (selection) of the mirror (light reflecting means) 23 is rotated to direct the optical path 25 to the PD (light receiving element) 35 (step). S4).

  The amount of light received by the PD (light receiving element) 35 is confirmed, and it is confirmed that the LD (light emitting element) 21 and the PD (light receiving element) 35 are connected by the optical path 25 (step S5). If the light emitted from the LD (light emitting element) 21 does not reach the PD (light receiving element) 35, the mirrors (light reflecting means) 23, 41 (42, 43, 44), 51 (52, 53, 54) are used. Adjust and rotate to allow light to reach (steps S2 to S5).

  When it is confirmed that the PD (light receiving element) 35 and the LD (light emitting element) 21 are connected by the optical path 25, the ink (printing colorant) 2 is ejected from the target recording element 3 (step S6). The amount of light received by the PD (light receiving element) 35 is confirmed, and it is determined whether or not the optical path 25 is blocked by the ink (printing colorant) 2 (step S7).

  If it is determined that the target recording element (nozzle) 3 is not shielded, it is determined that the target recording element (nozzle) 3 has abnormally discharged (including non-ejection), and is stored in the storage element (memory) 102. At the time of printing to be used, processing such as using an alternative recording element (nozzle) 3 is performed, or it is used for determining whether to perform maintenance during maintenance (step S8).

  On the other hand, when it is determined that the target recording element (nozzle) 3 has been blocked, it is determined that the target recording element (nozzle) 3 has normally ejected, and the target recording element (nozzle) 3 is stored. It is used to determine that the recording element (nozzle) 3 is ejected normally, or to determine that maintenance is not required during maintenance (step S9).

  Next, it is determined whether or not another recording element (nozzle) 3 of the same head (recording means) 11 (12, 13, 14) (or nozzle array) is detected (step S11). When detecting the same head (recording unit) 11 (12, 13, 14) (or nozzle row), the target recording element (nozzle) 3 is changed (steps S6 to S10) and executed repeatedly.

  On the other hand, when the recording element (nozzle) 3 to be detected does not exist in the same head (recording means) 11 (12, 13, 14) (or nozzle row), the target mirror (light reflecting means) 41 (42, 43, 44) is rotated to the protection position (step S11). Similarly, the mirror (light reflecting means) 51 (52, 53, 54) is rotated to the protection position (step S12).

  Subsequently, it is determined whether or not the next head (recording unit) 11 (12, 13, 14) (or nozzle row) is detected (step S13). When the next head (recording means) 12 (11, 13, 14) (or nozzle row) is detected, the mirror (light reflecting means) 23 is rotated and (S2 to S13) are repeatedly executed. When all the heads (recording means) 14 (11, 12, 13) and the recording elements (nozzles) 3 have been detected, the light emission of the LD light emitting element 25 is stopped (step S14).

  The target recording element (nozzle) 3 can be detected by the series of sequences described above.

  It is also possible to share ink droplets used in modes not directly related to printing, such as idle ejection (or pre-ejection), and also to perform main ejection detection. It is possible to save the amount of use and detection time.

  As described above, according to the present embodiment, the discharge detection mechanism of the recording unit including a plurality of light reflection units for rotation control is provided, the number of light emitting elements and light receiving elements is reduced, and discharge detection is performed with high accuracy. Can be done.

  In addition, detection accuracy can be improved by selecting the distribution of the detection optical path and adjusting the optical axis by controlling the rotation of the light reflecting means.

  Further, the number of light emitting elements can be reduced by distributing the detection optical path by controlling the rotation of the light reflecting means.

  Further, the number of light receiving elements can be reduced by condensing the detection optical path by controlling the rotation of the light reflecting means.

  Also, the detection accuracy can be improved by controlling the rotation of the light reflecting means before the detection operation.

  Further, by disposing the light reflecting means at the position where the light emitting element and the light receiving element are connected, it is possible to eliminate the need for highly accurate arrangement of the light reflecting means.

  In addition, since the light reflecting means can be controlled to rotate, mist contamination generated from the recording element can be prevented.

  Furthermore, since the light emitting element and the light receiving element can be arranged at positions away from the recording element, mist contamination generated from the recording element can be prevented.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments thereof, various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the invention as defined in the claims. is there.

1 is a schematic configuration diagram of an image forming apparatus. It is a block diagram which shows the discharge detection mechanism by the 1st Embodiment of this invention. It is a principal part perspective view of FIG. It is a block diagram which shows the discharge detection mechanism by the 2nd Embodiment of this invention. It is a block diagram which shows operation | movement of the discharge detection mechanism principal part. It is a block diagram which shows operation | movement of the discharge detection mechanism principal part. It is a block diagram which shows the principal part structure containing the electric circuit of a discharge detection mechanism. It is a flowchart which shows the discharge detection operation | movement of a discharge detection mechanism.

Explanation of symbols

1 paper (recording medium)
2 Ink (printing colorant)
3 Recording elements (nozzles)
4 Ink droplet flight path 11-14 Heads 1-4 (recording means)
21 LD (light emitting device)
23 mirror (light reflection means)
24 Turntable (Rotating means)
25 Optical path 31-34 PD5-8 (light receiving element)
35 PD (light receiving element)
41-44 Mirrors 1-4 with turntable (light reflecting means)
41A to 44A Mirrors 1 to 4 (light reflecting means)
41B-44B Turntables 1-4 (Rotating means)
51-54 Mirrors with turntable 5-8 (light reflection means)
51A to 54A Mirrors 5 to 8 (light reflecting means)
51B-54B Turntable 5-8 (Rotating means)
61 reflective surface 62 non-reflective surface 71 interior wall surface 81-84 drive circuits 1-4 (drive means)
91 Detection Circuit 101 Controller (CPU)
102 Memory element (memory)

Claims (6)

A plurality of recording means having recording elements for ejecting ink;
A light emitting means for emitting a light beam;
Condensing means for collimating the light beam emitted from the light emitting means;
A plurality of first light reflecting means for advancing the light beam parallel to the longitudinal direction vertically below the plurality of recording means by changing the incident angle of the light beam that is rotated and incident;
Second light reflecting means for causing the light beam to enter one of the first light reflecting means by changing the incident angle of the collimated light beam to the condensing means that is rotated and incident. When,
One or more light-receiving means which receives the said light beam, The discharge detection apparatus characterized by the above-mentioned.   2. The light reflecting surface of the first light reflecting means is directed in the opposite direction with respect to the recording means so as not to be affected by mist generated from the recording element when ejection is not detected. The discharge detection device described.   The plurality of first light reflecting means is provided at a facing position across the plurality of recording means, and is reflected by any one of the first light reflecting means to rotate and enter the incident light beam. The discharge detection apparatus according to claim 1, further comprising a third light reflecting unit that causes the light beam to enter the light receiving unit by changing an angle.   4. The third light reflecting means has a light reflecting surface directed in the opposite direction with respect to the recording means so as not to be affected by mist generated from the recording element when ejection is not detected. The discharge detection device described.   5. The discharge detection device according to claim 1, wherein the light reflection unit performs a rotation operation immediately before the discharge detection sequence of the recording unit.   An image forming apparatus comprising the ejection detection device according to claim 1.

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