JP2005199606A - Image forming device and recording head control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device and a recording head control method that protect the recording face of the recording head and a recording element at the time when an abnormality occurs. <P>SOLUTION: The recording head 50 is composed of seven recording heads corresponding to seven colors and each head is provided with a recording paper detection sensor 51 in the upstream side of the recording paper transfer direction and a recording paper detection sensor 52 in the downstream side. The presence of the recording paper 16 in a printing position and the positions of the leading edge and rear edge can be detected by using the sensors 51 and 52. When a jam occurs and the transfer of the recording paper 16 is suspended, the position of the recording paper 16 is detected by using the sensors 51 and 52, and in accordance with the position of the recording paper 16 detected, the heads 50A, 50B, 50C and 50D are withdrawn from the printing position to a prescribed withdrawal position. On the other hand, the heads 50E, 50F and 50G not withdrawn are covered with a cap 53 to prevent the ink in the nozzles from getting thickened. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus and a recording head control method, and more particularly to a recording head control technique for protecting a recording element and a recording head from being damaged in an abnormal state such as a paper jam.

  In recent years, inkjet printers have become widespread as data output devices for images and documents. Ink jet printers drive recording elements (nozzles) of a recording head according to data, and eject ink from the nozzles to form data on recording paper. As an ejection means for ejecting ink, there are one using a PZT actuator or the like that applies a pressure wave to a pressure chamber communicating with a nozzle, and another using a heat source that generates bubbles by heating ink in the pressure chamber. When ink pressurized by the operation of these ejection units is ejected from the nozzles, data such as an image is formed on the recording medium.

  In an ink jet printer, a power interruption may occur during recording due to a jam (paper jam), a power failure (instantaneous power failure), or accidentally turning off the power. In such an abnormal state, the conveyance of the recording medium is interrupted, and the recording medium stops in a state of facing the recording head.

  If the recording medium is left facing the recording head due to a jam or the like, the remaining recording medium must be removed when the recording head is initialized when recording is resumed. When removing the recording medium, the recording head is temporarily retracted to a predetermined position in order to prevent the recording medium from coming into contact with the recording head to contaminate or damage the recording surface (recording element). Etc. have been devised.

  Also, in order to prevent ejection failure due to ink thickening (drying) in an ink jet printer, when ink ejection is not performed for a long time, the recording head is moved to a predetermined capping position and is protected by a protective member such as a cap. The recording surface of the recording head is covered to protect the recording surface and the recording element.

  Further, since ink can be dried even when an abnormality such as a jam occurs, it is necessary to perform the maintenance operation by eliminating the abnormal state at an early stage, or to protect the recording surface of the recording head using a protective member such as a cap. .

In the ink jet printer described in Patent Document 1, by providing a shutter that covers the nozzle surface, even when the power supply is momentarily cut off, the solenoid is automatically turned off and the shutter is automatically closed, and the nozzle surface is immediately covered. Prevents drying and protects the nozzle surface. It is possible to prevent clogging of the nozzle under any environment even when the power is suddenly turned off.
JP-A-6-143608

  However, when the recording head is protected using a cap when a jam occurs, an electric drive for moving the recording head to a predetermined position is required. Further, when capping is performed when the cover is opened at the time of jam release, the apparatus stops due to the occurrence of the jam, and the recording head is not capped unless the jam release operation is started.

  Also, when capping is performed with the stored reserve energy when the power supply is cut off when the recording head is not at the home position (predetermined capping position), the power supply is not turned off by the power switch but is operating. In some cases, it may not be possible to deal with the case where the outlet is unplugged.

  In the ink jet printer disclosed in Patent Document 1, it is necessary to provide a shutter in addition to a cap for performing maintenance such as preliminary discharge and suction, which increases costs. Further, when the power is momentarily cut off during suction performed with the head capped, the cap and the nozzle surface are in close contact with each other, so that the shutter may not close or the shutter and the cap may interfere with each other. Further, when a jam occurs during printing, a jammed paper may stick to the nozzle surface, and the paper may be pinched by the shutter, and the shutter may not be reliably closed.

  The present invention has been made in view of such circumstances, and an image forming apparatus and a recording apparatus that can protect the recording surface and the recording element of the recording head even when an abnormality occurs such as a jam or unexpected power interruption. It is an object to provide a head control method.

  In order to achieve the above object, the invention according to claim 1 is directed to a recording unit having a plurality of line-type recording heads in which a plurality of recording elements are arranged in the width direction of the recording medium, the recording medium, and the recording unit. Conveying means for relatively moving at least one of the recording medium in a direction substantially perpendicular to the width direction of the recording medium, upstream and downstream of the recording medium relative conveyance direction of each recording head, A detection means for detecting the recording medium when the recording head is at a predetermined recording position, a recording head movement driving means for moving the recording head from the recording position to a predetermined retracted position, and a relative relationship between the recording medium When the conveyance is interrupted, the recording head in the recording unit is controlled to selectively move to a predetermined retracted position according to the position of the recording medium detected by the detecting unit. It is characterized by comprising a head control unit, the.

  That is, in a recording means having a plurality of line-type recording heads having a predetermined length in the width direction of the recording medium, each recording head has the recording heads on the upstream side and the downstream side in the recording medium relative conveyance direction. A detecting means for detecting the position of the recording medium at the recording position is provided, and when the recording medium is interrupted by a jam or the like, the position of the recording medium is detected, and the position of the recording medium is Since the corresponding recording head is moved to a predetermined retracted position, it becomes easy to remove the recording medium in a state where the conveyance is interrupted or the recording medium that is jammed.

  Further, it is possible to prevent the recording surface of the recording head from being damaged or soiled by these recording media.

  Furthermore, since only the recording head that needs to be retreated is moved, the recording head moving drive means for moving each recording head can be reduced in size.

  Since the detection means are provided on the upstream side and the downstream side in the relative conveyance direction of the recording head, not only the presence / absence of the recording medium, but also the recording head under which recording head, etc. The position of the recording medium can be detected in detail.

  Further, the detection means can be used for both detection of a recording medium during conveyance (during normal conveyance) and detection of a recording medium during jamming.

  The line type recording head may include a full line type recording head corresponding to the full printable width of the recording medium, or a divided type head having a plurality of recording heads in the width direction of the recording medium. .

  The recording medium includes various media regardless of the material and shape, such as continuous paper, cut paper, sticker paper, resin sheet such as OHP sheet, film, cloth, and the like.

  As the detection means, a reflection type sensor or a transmission type sensor may be used. An image sensor such as a CCD may be used. Further, the detection means between adjacent recording heads may be shared.

  As a mode of selecting the recording head to be retracted, a head in which the recording medium is positioned may be selected, or heads before and after the recording medium may be selected in combination. Further, all heads may be selected.

  The predetermined retraction position may be an upper position of the recording head or a side position. Moreover, the position which combined the upper position and the side position may be sufficient.

  When an abnormal state such as a jam is detected, the conveyance of the recording medium by the conveying unit may be interrupted, the position of the recording medium may be detected, and the selected recording head may be automatically retracted. .

  In such a case of automatically retracting the recording head, upon receiving a detection signal of an abnormal state, the conveyance is immediately stopped and the position of the recording medium is determined from the detection signal for detecting the position of the recording medium. Then, it is only necessary to provide a control means for selecting the recording head to be retracted based on the detection result and controlling the recording head movement driving means to give a drive signal.

  According to a second aspect of the present invention, in the first aspect of the present invention, the recording head sealing means is mounted so as to cover the recording surface of the recording head, and the recording head control means is configured to perform relative conveyance of the recording medium. Control is performed so that the recording surface sealing means is attached to the recording surface of the recording head that is not moved by the recording head movement driving means when interrupted.

  That is, since the recording surface sealing means is attached to the recording surface of the recording head that is not moved to the retracted position when the conveyance of the recording medium is interrupted, the recording elements and recording surfaces of these recording heads can be reliably protected. Can do.

  In particular, in an ink jet recording apparatus that forms an image on a recording medium by ejecting ink droplets from nozzles of a recording head, if the ink is not ejected continuously, the ink in the nozzles thickens and causes the ejection failure. It becomes. Even if the non-ejection time is continued due to the interruption of conveyance of the recording medium, the recording element and the recording surface of the recording head are protected by the recording surface sealing means, and the viscosity increase of the ink in the nozzle is suppressed.

  The recording surface sealing means includes a cap that is attached to the nozzle surface in order to prevent thickening of ink in the nozzle in the ink jet recording apparatus and to protect the nozzle surface.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the detection means includes a plurality of detectors on the upstream side and the downstream side in the relative conveyance direction of the recording medium of each recording head. The detector is arranged at a position corresponding to the width of the recording medium along a direction substantially orthogonal to the relative conveyance direction of the recording medium.

  When the recording medium has a plurality of widths, detectors (sensors) may be arranged corresponding to the respective widths. For example, when there is a recording medium having a width substantially the same as the width of the recording head and a recording medium having a width that is approximately ½ of the width of the recording head, one at each of both ends and substantially the center of the recording head. It is sufficient to provide three (a total of six) detectors on the upstream side and the downstream side. In the case where there is only one type of recording medium width, two detectors (four in total) may be provided on each of the upstream side and the downstream side.

  According to a fourth aspect of the present invention, in the invention according to the second or third aspect, the recording surface sealing means includes a detected means that can be detected by the detector disposed at a diagonal position of the recording head. It is characterized by that.

  That is, by devising the arrangement of the detected means provided in the recording surface sealing means, it is possible to detect the recording medium and to detect the mounting of the recording surface sealing means using the detecting means, and the recording surface sealing means performs recording. It can be detected that the head is securely attached.

  At the diagonal position of the recording head, the recording means corresponding to the upstream detector in the recording medium conveyance direction is provided on one side in the longitudinal direction of the recording head, and the detected means corresponding to the downstream detector is the recording head. There is an aspect provided on the other side in the longitudinal direction of the head.

  In the detection of the recording medium, the detectors arranged diagonally corresponding to the recording means as described above do not turn on at the same time, so it can be determined that the recording surface sealing means has been detected.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the detection means is configured integrally with the recording head.

  In other words, the position of the head unit including the recording head can be detected by integrally configuring the detection means with each recording head. For example, the position of the recording head can be detected when each recording head returns from the retracted position to the recording position.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the recording head movement driving means releases a force that biases the recording head in a predetermined direction. And a mechanism for moving the recording head by elastic deformation generated in the recording medium.

  That is, since each recording head can be moved by a driving force generated by elastic deformation without electrical driving, each recording head can be reliably retracted even when the power is momentarily interrupted or unexpectedly interrupted.

  As an example of a mechanism by elastic deformation, a biasing mechanism that biases each recording head in a certain direction by an elastic force such as a spring is used. When the power is turned on, a force is applied in a direction (opposite) different from the biasing direction. When the recording head is held as it is applied (ie, the elastic deformation of the spring is held) and this holding is released in response to power-off, the recording head is moved in the biasing direction by the restoring force of the spring Can be made.

  According to the invention described in any one of claims 1 to 6 as shown in claim 7, the retreat mounted so as to cover the recording surface of the recording head at the retracted position of the recording head. It is characterized by having a recording surface sealing means.

  That is, even when each recording head is in the retracted position, the recording element and recording surface of the recording head are protected by the recording surface sealing means when retracted.

  The retraction recording surface sealing means may have the same configuration as the recording surface sealing means or a different configuration. For example, either one may be provided with a recovery operation function such as purge or suction in addition to the recording element recording surface protection function, and the other may be provided with only the recording element and recording surface protection function.

  It is preferable that the driving force by elastic deformation shown in claim 7 is used as the driving force for mounting the recording surface sealing means on the recording surface during retraction.

  According to the invention described in any one of claims 1 to 7 as shown in claim 8, there is provided a recording medium peeling means for peeling the recording medium attached to the recording surface of the recording head. It is characterized by that.

  That is, even if a jammed recording medium adheres to the recording surface, it can be surely peeled off. Further, if the recording medium remains attached to the recording surface, the recording medium may be sandwiched between the recording surface sealing means during retraction and the recording surface, and the effect of using the recording surface sealing means during retraction is effective. In some cases, the recording surface cannot be obtained, or the recording surface is soiled or damaged by the recording medium. That is, these problems can be prevented by the recording medium removing means.

  The recording medium peeling means may be integrated so as to serve as a recording surface sealing means during retraction, or may be configured to be attached to the recording surface sealing means during retraction.

  The invention according to claim 9 which achieves the above object is a recording means comprising a plurality of full-line type recording heads in which a plurality of recording elements are arranged on the recording surface over a length corresponding to the printable width of the recording medium. A recording head control method for an image recording apparatus comprising: a recording medium; and a conveying unit configured to relatively move at least one of the recording medium and the recording unit in a direction substantially orthogonal to a width direction of the recording medium. A transporting process in which the recording medium is relatively transported by the transporting means, and detection means provided on the upstream side and the downstream side in the recording medium relative transporting direction of each recording head in the transporting process. When the detection process for detecting the recording medium when each recording head is at a predetermined recording position and the relative conveyance of the recording medium by the conveying means are interrupted, the detection process by the detection process is interrupted. It is characterized in that it comprises a retraction stroke for retracting the recording head corresponding to the detected position of the recording medium to a predetermined holding position.

  According to a tenth aspect of the present invention, the invention according to the ninth aspect includes a maintenance step of performing maintenance of the recording head that has been retracted to a predetermined retracted position by the retracting step.

  That is, since only the retracted recording head that requires maintenance is configured to perform maintenance, it is possible to reduce consumption of ink and the like.

  According to the present invention, in an image recording apparatus including a recording unit having a plurality of line-type recording heads, the position of the recording medium is set on the upstream side and the downstream side in the recording medium relative transport direction of each head. Since the detecting means for detecting is provided, the position of the recording medium including the leading edge and the trailing edge of the recording medium can be detected in detail when each recording head is at the printing position. When the conveyance of the recording medium is interrupted, the position of the recording medium is detected by using the detection means, and the recording head is moved to a predetermined retracted position according to the detection position of the recording medium. It becomes easy to remove the interrupted recording medium. The recording head that is not retracted preferably has a recording surface sealing means.

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

[Overall configuration of inkjet recording apparatus]
FIG. 1 is an overall configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. As shown in the figure, the ink jet recording apparatus 10 includes a printing unit 12 having a plurality of printing heads provided for each ink color, and ink storage / loading for storing ink to be supplied to each printing head. A recording unit 16, a paper feeding unit 18 that supplies the recording paper 16, a decurling unit 20 that removes curling of the recording paper 16, and a nozzle surface (ink ejection surface) of the printing unit 12. The suction belt conveyance unit 22 that conveys the recording paper 16 while maintaining the flatness of the paper 16, the print detection unit 24 that reads the printing result by the printing unit 12, and the printed recording paper (printed material) is discharged to the outside. And a paper discharge unit 26.

  In FIG. 1, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 18, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  When multiple types of recording paper are used, an information recording body such as a barcode or wireless tag that records paper type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Therefore, it is preferable to automatically determine the type of paper to be used and perform ink ejection control so as to realize appropriate ink ejection according to the type of paper.

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine in the decurling unit 20. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  In the case of an apparatus configuration that uses roll paper, a cutter (first cutter) 28 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is disposed on the printing surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  After the decurling process, the cut recording paper 16 is sent to the suction belt conveyance unit 22. The suction belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least portions facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 are horizontal ( Flat surface).

  The belt 33 has a width that is wider than the width of the recording paper 16, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 1, a suction chamber 34 is provided at a position facing the nozzle surface of the print unit 12 and the sensor surface of the print detection unit 24 inside the belt 33 spanned between the rollers 31 and 32. Then, the suction chamber 34 is sucked by the fan 35 to be a negative pressure, whereby the recording paper 16 on the belt 33 is sucked and held.

  When the power of a motor (not shown in FIG. 1, not shown in FIG. 4) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, the belt 33 rotates counterclockwise in FIG. The recording paper 16 driven in the direction and held on the belt 33 is conveyed from right to left in FIG.

  Since ink adheres to the belt 33 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area). Although details of the configuration of the belt cleaning unit 36 are not shown, for example, there are a method of niping a brush roll, a water absorbing roll, etc., an air blow method of blowing clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  Although a mode using a roller / nip conveyance mechanism instead of the suction belt conveyance unit 22 is also conceivable, if the roller / nip conveyance is performed in the print area, the image easily spreads because the roller contacts the printing surface of the sheet immediately after printing. There is a problem. Therefore, as in this example, suction belt conveyance that does not bring the image surface into contact with each other in the print region is preferable.

  A heating fan 40 is provided on the upstream side of the printing unit 12 on the paper conveyance path formed by the suction belt conveyance unit 22. The heating fan 40 heats the recording paper 16 by blowing heated air onto the recording paper 16 before printing. Heating the recording paper 16 immediately before printing makes it easier for the ink to dry after landing.

  The printing unit 12 is a so-called full-line head in which a line-type head having a length corresponding to the maximum paper width is arranged in a direction orthogonal to the paper feeding direction (recording paper conveyance direction) (see FIG. 2). Although a detailed structure example will be described later, as shown in FIG. 2, each print head has an ink discharge port (nozzle) over a length exceeding at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10. ) Is composed of a plurality of line-type heads arranged.

  A print head corresponding to seven color inks is arranged in the printing unit 12 along the recording paper conveyance direction. A color image can be formed on the recording paper 16 by discharging the color ink from each print head while conveying the recording paper 16.

  As described above, according to the printing unit 12 in which the full line head that covers the entire width of the paper is provided for each ink color, the operation of relatively moving the recording paper 16 and the printing unit 12 in the recording paper transport direction is performed. The image can be recorded on the entire surface of the recording paper 16 only by performing it once (that is, by scanning once in the recording paper conveyance direction). Thus, high-speed printing is possible and productivity can be improved as compared with a serial (shuttle scan) type head in which the print head reciprocates in a direction substantially perpendicular to the recording paper conveyance direction.

  In this example, the configuration of seven color inks of black, cyan, magenta, yellow, light cyan, light magenta, and dark yellow is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and dark Red may be provided instead of yellow, or a configuration of standard colors (4 colors) of KCMY or a configuration of 6 colors excluding dark yellow may be used.

  As shown in FIG. 1, the ink storage / loading unit 14 has a tank for storing ink of a color corresponding to each print head, and each tank is communicated with each print head via a conduit (not shown). ing. Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means, etc.) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. doing.

  The print detection unit 24 includes an image sensor for imaging the droplet ejection result of the print unit 12, and functions as a means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor.

  The print detection unit 24 of this example is composed of a line sensor having a light receiving element array that is wider than at least the ink discharge width (image recording width) of each print head. The line sensor includes an R sensor row in which photoelectric conversion elements (pixels) provided with red (R) color filters are arranged in a line, a G sensor row provided with green (G) color filters, The color separation line CCD sensor is composed of a B sensor array provided with a blue (B) color filter. Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used.

  The print detection unit 24 reads a test pattern (or an actual image) printed by each color print head and detects ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like. In addition, the print detection unit 24 includes a light source (not shown) that irradiates light to the ejected dots.

  A post-drying unit 42 is provided following the print detection unit 24. The post-drying unit 42 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by blocking the paper holes by pressurization. There is an effect to.

  A heating / pressurizing unit 44 is provided following the post-drying unit 42. The heating / pressurizing unit 44 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 45 having a predetermined surface uneven shape while heating the image surface to transfer the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 26. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 10 is provided with a sorting means (not shown) for switching the paper discharge path in order to select the print product of the main image and the print product of the test print and send them to the discharge units 26A and 26B. Yes. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by a cutter (second cutter) 48. The cutter 48 is provided immediately before the paper discharge unit 26, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the cutter 48 is the same as that of the first cutter 28 described above, and includes a fixed blade 48A and a round blade 48B.

  Although not shown in FIG. 1, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders. Reference numeral 26B denotes a test print discharge unit.

  Next, the structure of the recording head 50 will be described. Since the structures of the recording heads 50A, 50B, 50C, 50D, 50E, 50F, and 50G provided for each ink color are the same, the recording head is represented by reference numeral 50 below. .

  The recording heads 50 are arranged in the order of black, cyan, light cyan, magenta, light magenta, dark yellow, and yellow from the upstream side in the recording paper conveyance direction (sometimes simply referred to as the upstream side). That is, the recording head 50A is black, 50B is cyan, 50C is light cyan, 50D is magenta, 50E is light magenta, 50F is dark yellow, and 50G is yellow. The above-described arrangement order of the print heads is merely an example, and a mode in which the print heads are arranged in an order other than this may be applied.

  Further, the recording head 50 includes a recording paper detection sensor 51 on the upstream side and a recording paper detection sensor 52 on the downstream side in order to detect the presence or absence of the recording paper in the print area. The recording paper detection sensors 51 and 52 are 51A, 51B,..., 51G, 52A, 52B,.

  In the recording paper detection sensors 51 and 52, a light emitting unit that emits detection light such as infrared light and a light receiving unit that receives the detection light are arranged in the same direction, and detection is reflected by an object to be detected such as the recording paper 16. A reflection sensor that detects the position of the recording paper 16 when the light receiving unit receives the light is applied. Of course, a transmission type sensor that detects the object to be detected by transmitting / blocking the detection light by arranging the light emitting unit and the light receiving unit to face each other may be applied.

  Each recording head 50 is provided with a cap 53 (53A, 53B, 53C, 53D, 53E, 53F, 53G) for the purpose of preventing ink drying and protecting the printing surface.

  In FIG. 2, the direction indicated by K indicates the conveyance direction of the recording paper.

  FIG. 3 is a perspective plan view showing an example of the structure of the recording head 50. In order to increase the dot pitch printed on the recording paper surface, it is necessary to increase the nozzle pitch in the recording head 50. As shown in FIG. 3, the recording head 50 of this example includes a nozzle 54 for ejecting ink droplets, a pressure chamber 55 corresponding to each nozzle 54, a supply port 56 for supplying ink from a supply system to the pressure chamber 55, and the like. A plurality of ink chamber units 57 are arranged in a staggered matrix, thereby achieving a high density of the apparent nozzle pitch.

  That is, in the recording head 50 in this embodiment, as shown in FIG. 3, a plurality of nozzles 54 that eject ink are arranged over a length corresponding to the entire width of the print medium in a direction substantially orthogonal to the print medium feed direction. This is a full line head having one or more nozzle rows.

  Although not shown, short two-dimensionally arranged heads may be arranged in a zigzag manner and connected to form a length corresponding to the entire width of the print medium.

  The pressure chamber 55 provided corresponding to each nozzle 54 has a substantially square planar shape, and nozzles 54 and supply ports 56 are provided at both corners on a diagonal line. Each pressure chamber 55 communicates with a common channel (not shown) through a supply port 56.

  An actuator (not shown) provided with individual electrodes is joined to a diaphragm (not shown) constituting the top surface of the pressure chamber 55, and the actuator is deformed by applying a drive voltage to the individual electrodes, so that the nozzle Ink is ejected from 54. When ink is ejected, new ink is supplied from the common flow path to the pressure chamber 55 through the supply port 56.

  As shown in FIG. 3, the ink chamber unit 57 is arranged along a row direction along a direction (main scanning direction) substantially perpendicular to the recording paper conveyance direction and an oblique column direction having a certain angle not orthogonal to the main scanning direction. It has a structure that is arranged in a grid with a fixed arrangement pattern, and with this structure, the nozzle rows projected so as to be aligned in the main scanning direction have a high density of 2400 nozzles per inch (2400 nozzles / inch). A nozzle configuration can be realized. Hereinafter, for convenience of explanation, it is assumed that the nozzles 54 are linearly arranged at regular intervals along the longitudinal direction of the head (main scanning direction). In the implementation of the present invention, the nozzle arrangement structure is not limited to the illustrated example.

  In this embodiment, a method of ejecting ink droplets by deformation of an actuator typified by a piezo element (piezoelectric element) is employed. However, when the present invention is implemented, ink is put into the pressure chamber (ink chamber) 55. A thermal system that has a heat source that generates bubbles by heating and discharges ink in the ink chamber by the energy generated by the bubbles may be applied.

  Further, the inkjet recording apparatus 10 is provided with a cap 53 as a means for preventing the nozzle 54 from drying or preventing an increase in ink viscosity near the nozzle 54 and a cleaning blade (not shown) as a means for cleaning the nozzle surface. Yes.

  The maintenance unit including the cap 53 and the cleaning blade can be moved relative to the recording head 50 by a moving mechanism (not shown), and is moved from a predetermined retracted position to a maintenance position below the recording head 50 as necessary. .

  The cap 53 is displaced up and down relatively with respect to the recording head 50 by an elevator mechanism (not shown). The cap 53 is raised to a predetermined raised position when the power is turned off or during printing standby, and is brought into close contact with the recording head 50 so that the nozzle surface (ink ejection surface) is covered with the cap 53.

  During printing or standby, if the frequency of use of a specific nozzle 54 is low and ink is not ejected for a certain period of time, the ink solvent near the nozzle evaporates and the ink viscosity increases. In such a state, ink cannot be ejected from the nozzle 54 even if the actuator operates.

  Before such a state is reached (within the range of viscosity that can be discharged by the operation of the actuator), the actuator is operated, and the cap 53 (ink receiver) is discharged to discharge the deteriorated ink (ink in the vicinity of the nozzle whose viscosity has increased). ), Preliminary discharge (purge, idle discharge, spit) is performed.

  Further, when air bubbles are mixed into the ink in the recording head 50 (in the pressure chamber 55), the ink cannot be ejected from the nozzle even if the actuator operates. In such a case, the cap 53 is applied to the recording head 50, and the ink (ink mixed with air bubbles) in the pressure chamber 55 is removed by suction with a suction pump (not shown), and the ink removed by suction is sent to the ink collection system. Deliver liquid.

  In this suction operation, the deteriorated ink with increased viscosity (solidified) is sucked out when the ink is initially loaded into the head or when the ink is used after being stopped for a long time. Since the suction operation is performed on the entire ink in the pressure chamber 55, the amount of ink consumption increases. Therefore, it is preferable to perform preliminary ejection when the increase in ink viscosity is small.

  The cleaning blade is made of an elastic member such as rubber, and can be slid on the ink discharge surface (nozzle plate surface) of the recording head 50 by a blade moving mechanism (wiper) (not shown). When ink droplets or foreign matter adheres to the nozzle plate, the nozzle plate surface is wiped by sliding the cleaning blade on the nozzle plate to clean the nozzle plate surface. It should be noted that when the ink ejection surface is cleaned by the blade mechanism, preliminary ejection is performed in order to prevent foreign matter from being mixed into the nozzle 54 by the blade.

  FIG. 4 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10. The inkjet recording apparatus 10 includes a communication interface 70, a system controller 72, an image memory 74, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, a head driver 84, and the like.

  The communication interface 70 is an interface unit that receives image data sent from the host computer 86. As the communication interface 70, a serial interface such as USB, IEEE 1394, Ethernet, and wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory (not shown) for speeding up communication may be mounted. Image data sent from the host computer 86 is taken into the inkjet recording apparatus 10 via the communication interface 70 and temporarily stored in the image memory 74. The image memory 74 is a storage unit that temporarily stores an image input via the communication interface 70, and data is read and written through the system controller 72. The image memory 74 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The system controller 72 is a control unit that controls each unit such as the communication interface 70, the image memory 74, the motor driver 76, and the heater driver 78. The system controller 72 includes a central processing unit (CPU) and its peripheral circuits, and performs communication control with the host computer 86, read / write control of the image memory 74, and the like, as well as a transport system motor 88 and heater 89. A control signal for controlling is generated.

  The motor driver 76 is a driver (drive circuit) that drives the motor 88 in accordance with an instruction from the system controller 72. 4 shows only the motor driver 76 and the motor 88, the system controller 72 controls a plurality of motor drivers and motors.

  The heater driver 78 is a driver that drives the heater 89 such as the post-drying unit 42 in accordance with an instruction from the system controller 72.

  The print control unit 80 has a signal processing function for performing various processing and correction processing for generating a print control signal from the image data in the image memory 74 according to the control of the system controller 72, and the generated print A control unit that supplies a control signal to the head driver 84. Necessary signal processing is performed in the print controller 80, and the ejection amount and ejection timing of the ink droplets of the recording head 50 are controlled via the head driver 84 based on the image data. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 80 includes an image buffer memory 82, and image data, parameters, and other data are temporarily stored in the image buffer memory 82 when image data is processed in the print control unit 80. In FIG. 4, the image buffer memory 82 is shown in a form associated with the print control unit 80, but it can also be used as the image memory 74. Also possible is an aspect in which the print controller 80 and the system controller 72 are integrated and configured with a single processor.

  The head driver 84 drives the actuator of the recording head 50 for each color based on the print data given from the print controller 80. The head driver 84 may include a feedback control system for keeping the head driving conditions constant.

  As will be described in detail later, when a jam occurs, the inkjet recording apparatus stops the operation of the suction belt conveyance unit, stops conveyance of the recording paper 16, detects the position of the recording paper 16, and based on the detection result. It has a function of selectively retracting the recording head 50.

  That is, when the conveyance of the recording paper 16 is interrupted, the recording paper detection signals of the recording paper detection sensors 51 and 52 are sent to the system controller 72, and the position of the recording paper 16 is determined in the system controller 72. A recording head to be retracted is selected based on the recording paper detection position. In order to operate the moving mechanism 90 of the selected recording head, a drive command is sent from the system controller 72 to the driver 92.

[First Embodiment]
Next, the ink jet recording apparatus according to the first embodiment of the present invention will be described. The ink jet recording apparatus 10 includes position detection means for detecting the position of the recording paper 16 in the print area. The position detection means detects the position of the recording paper 16 when an abnormality such as a jam (paper jam) occurs, and adjusts accordingly. Then, control of the recording head 50 is executed.

  Note that the printing area here refers to an area in which the printing surface (nozzle surface) of the recording head 50 and the recording paper 16 face each other and image formation is performed on the recording paper by ink ejected from the nozzles 54. .

  FIG. 5 shows recording sheet position detection for detecting the position of the recording sheet 16 in the printing area. In FIG. 5, the recording paper detection sensors 51A, 52A, 51B, 52B, 51C, 52C, and 51D indicated by diagonal lines are on, the leading edge of the recording paper 16 faces the recording head 50D, and the recording paper detection sensor 51D. And 52D (that is, below the recording head 50D).

  That is, by using the recording paper detection sensors 51 and 52 provided in each print head, the upstream recording paper detection sensor (head front sensor) 51 is turned on, and the downstream recording paper detection sensor (head rear sensor) 52 is turned on. When it is on, it is recognized that the recording paper 16 is under the print head. When the upstream recording paper detection sensor 51 is on and the downstream recording paper detection sensor 52 is off, it is recognized that the leading edge of the recording paper 16 is under the print head, and the upstream recording paper detection sensor 51 When the recording paper detection sensor 52 on the downstream side is off, it is recognized that the trailing edge of the recording paper 16 is under the print head. On the other hand, when the upstream recording paper detection sensor 51 is off and the downstream recording paper detection sensor 52 is off, it is recognized that there is no recording paper 16 under the print head.

  When an abnormality in conveyance of the recording paper 16 is detected during recording (bending or clogging of the recording paper 16), printing is stopped and the conveyance of the recording paper 16 is performed by a control system including the system controller 72 shown in FIG. Control is performed to stop the operation. In addition, control is performed by the control system so as to notify an abnormal state using an alarm or an error message.

  In order to resume printing, it is necessary to remove the cause of the abnormality and initialize the recording head 50 (initialization operation). For example, when a jam occurs, first, the recording paper 16 that is jammed in the print area that is the cause of the abnormality is removed, and the recording head 50 is initialized.

  FIG. 6 shows the operation of the recording head 50 when a jam occurs.

  When the jam occurs, the jammed recording paper 16 cannot be ejected by conveyance using the belt 33, so the paper ejection operation must be performed manually. The interval between the recording head 50 and the belt 33 is generally about several millimeters, which not only makes it difficult to remove the jammed recording paper 16 but also makes the print surface of the recording head 50 dirty when the jammed recording paper 16 is removed. The printing surface recording paper may stick and cannot be removed.

  Therefore, in the ink jet recording apparatus 10, when an abnormality such as a jam occurs, control is performed so that the recording head 50 is automatically retracted from the printing area to a predetermined retracting position.

  For example, when it is detected that the leading edge of the recording paper 16 is below the recording head 50D when a jam occurs, the recording heads 50A, 50B, 50C, and 50D are moved upward using the head moving mechanism 90 shown in FIG. Retreat to a predetermined retraction position. When the recording heads 50A, 50B, 50C, and 50D are retracted upward, the removal operation of the jammed recording paper 16 is facilitated.

  In addition to the upper position of the recording head 50, the predetermined retracted position may be a side position or a position where the upper position and the side position are combined.

  Although FIG. 6 illustrates a mode in which the recording heads 50E, 50F, and 50G are not retracted, the recording head 50 may be configured to be retracted. If the entire recording head 50 is retracted, it is not necessary to provide a retracting mechanism for each print head.

  Further, if the ejection is not performed for a certain time or more, the ink in the nozzle 54 is thickened, resulting in ejection failure (non-ejection). The same applies when the abnormal state canceling operation is not performed for a certain period of time. In order to prevent this, the ink jet recording apparatus 10 is controlled to perform capping in an abnormal state to prevent thickening of the ink in the nozzle 54 and protect the printing surface.

  For example, as shown in FIG. 6, the recording heads 50E, 50F, and 50G that are not retracted are immediately capped and capped. During the initialization operation, the capping print head does not perform the recovery operation, and only the print head that does not perform capping needs to perform the recovery operation.

  However, in the aspect in which the entire recording head 50 is retracted to the retracted position, capping cannot be performed when the retracted position is different from the capping position. Therefore, at the time of initialization, control is performed so that the recovery operation is performed for all the print heads.

  In the present embodiment, an example in which the recording paper detection sensors 51 and 52 are provided on the upstream side and the downstream side of each print head has been exemplified. However, the sensors between the print heads may also be used. For example, in the sensors 52A and 51B, the sensors 52B and 51C, etc., two sensors may be replaced with one sensor.

  In the present exemplary embodiment, an example in which the recording head 50 is retracted to the retracted position when an abnormal state occurs is illustrated, but the suction belt conveyance unit 22 may be moved. That is, at least one of the recording head 50 and the suction belt conveyance unit 22 may be moved to change the relative position between the recording head 50 and the belt conveyance unit 22.

  FIG. 7 shows the arrangement of the recording paper detection sensors 51 and 52 provided in the recording head 50. 7A) is a plan view of the recording head 50 as viewed from above, FIG. 7B) is a front view of the recording head 50 as viewed from the upstream side in the recording paper conveyance direction, and FIG. 7C) is a side view of the recording head 50.

  As shown in FIG. 7a), the recording paper detection sensor 51 includes a sensor 100 attached to one end of the recording head 50, a sensor 102 attached to the approximate center of the recording head 50, and the other of the recording head 50. It is comprised from the sensor 104 attached to the substantially edge part.

  The recording paper detection sensor 52 has the same configuration as the recording paper detection sensor 51, and includes a sensor 110 attached to one of the ends of the recording head 50, a sensor 112 attached to the approximate center of the recording head 50, The sensor 114 is attached to the other substantially end portion of the recording head 50.

  On the other hand, the cap 53 is provided with a light shielding plate 120 corresponding to the sensor 100 and a sensor plate 122 corresponding to the sensor 114. In other words, the cap 53 is provided with light shielding plates on the upstream side and the downstream side, respectively, and the upstream light shielding plate and the downstream light shielding plate are arranged at diagonal positions with respect to the recording head 50. Yes.

  In the inkjet recording apparatus 10, capping detection of the cap 53 can be performed in addition to the position detection of the recording paper 16 using the recording paper detection sensors 51 (100) and 52 (114) shown in FIG. 7.

  Next, recording sheet position detection and capping detection will be described in detail with reference to FIGS. FIG. 8 shows a case where the recording paper 16 is detected, and FIG. 9 shows a case where the cap 53 is detected.

  In FIG. 8, the sensor 102 and the sensor 112 are turned on. This shows a state where the recording paper 16 is positioned under the recording head 50. When the recording paper 16 is bent and conveyed due to skew, other sensors may be turned on. For example, when the recording paper 16 is skewed clockwise in FIG. 8, one of the sensor 100 and the sensor 114 may be turned on. If the position of the recording paper 16 is shifted toward the sensor 104, the sensor 104 and the sensor 114 may be turned on.

  That is, in order to detect that the recording paper 16 is under the recording head 50, at least the sensor 102 and the sensor 112 need only be turned on.

  Although not shown in the drawing, when detecting the leading edge of the recording paper 16, it is sufficient that at least one of the sensors 100, 102, 104 is on and all the sensors 110, 112, 114 are off. .

  Further, when detecting the trailing edge of the recording paper 16, it is sufficient that at least one of the sensors 110, 112, and 114 is on and all the sensors 100, 102, and 104 are off.

  FIG. 9 shows the time of detecting the position of the cap 53 (capping detection). In FIG. 9, the sensor 100 and the sensor 114 are on, and the other sensors are off.

  That is, the sensor 100 is turned on by the light shielding plate 120 provided on the cap 53, and the sensor 114 is turned on by the light shielding plate 122, which indicates that the recording head 50 is reliably capped. Further, when the cap 53 is moved from the capping position, it is possible to detect that the cap has been avoided without being a combination of ON / OFF of the sensor such that only the sensor 100 and the sensor 114 are ON and all other sensors are OFF. .

  That is, if the light shielding plate provided on the cap 53 is arranged so that the combination of ON / OFF of the recording paper detection sensors 51 and 52 cannot be realized by the detection of the recording paper 16, the cap 53 is reliably capped and retracted. It can be confirmed whether or not it was performed.

  In the present embodiment, an example in which six sensors are provided in one print head is illustrated, but the number of sensors may be two on the upstream side and two on the downstream side. However, in order to cope with a plurality of paper widths (especially in the case of two-row simultaneous conveyance), an aspect including at least six sensors is preferable.

  For example, in the aspect shown in FIG. 8, the sensor 102 and the sensor 112 may be omitted. In this case, it is necessary to set the distance between the sensor 100 and the sensor 104 and the distance between the sensor 110 and the sensor 114 to the distance corresponding to the minimum sheet width.

  The inkjet recording apparatus 10 configured as described above includes recording sheet detection sensors 51 and 52 on the upstream side and the downstream side in the recording sheet conveyance direction of each print head, and whether the recording sheet 16 is under the print head, Whether there is a leading edge or a trailing edge of the recording paper 16 can be detected. In an abnormal state such as a jam, the position of the recording paper 16 is detected by the recording paper detection sensors 51 and 52, and the print head under the recording paper 16 in the printing area is retracted to a predetermined retracting position, so that it is clogged. It is easy to remove the paper and the like, and it is possible to prevent the print surface of the recording head 50 from being soiled or damaged by the jammed paper.

  Further, since the print head that is not retracted (that is, the print head without the recording paper 16) is immediately capped using the cap 53, the ink in the nozzle 54 can be prevented from thickening (drying).

  On the other hand, when the cap 53 is provided with a light shielding plate at a position corresponding to the recording paper detection sensors 51 and 52, the recording paper detection sensors 51 and 52 detect whether or not capping and capping avoidance have been reliably performed. Can do. The light shielding plates 120 and 122 provided on the cap 53 are arranged so that the combination of ON / OFF of the recording paper detection sensors 51 and 52 at the time of capping detection is different from that when the recording paper 16 is detected. The

[Second Embodiment]
Next, an ink jet recording apparatus according to a second embodiment of the present invention will be described. The inkjet recording apparatus according to the second embodiment includes two caps in one recording head, and one cap can perform a capping operation without electrical driving. In the second embodiment, the overall configuration of the inkjet recording apparatus is the same as that of the inkjet recording apparatus 10 according to the first embodiment, and a description thereof will be omitted.

  FIG. 10 is a diagram illustrating two caps provided in the recording head 50. The cap 53 provided at the lower part of the recording head 50 functions as a main cap, and can perform a recovery operation such as suction in addition to capping.

  When the recording head 50 is moved to the first capping position by a first moving mechanism (not shown), the recording head 50 is mounted so as to cover the printing surface of the recording head 50 by a main cap moving mechanism (not shown). When the recording head 50 is capped by the main cap 53, the belt 33 (belt conveyance unit 22) may be moved.

  In addition, the recording head 50 includes a sub-cap 200 used for capping at the second capping position (recording head avoidance position in an abnormal state). The sub-cap 200 is used to prevent the print surface of the recording head 50 from drying in an abnormal state such as a jam or when the power is turned off. The subcap 200 does not have a function of performing a recovery operation such as suction.

  The sub cap 200 is supported by a V-shaped arm 204 that can be rotated about a rotating shaft 202, and is capped on the print surface of the recording head 50 by the rotation of the V-shaped arm 204. In the capped state, the sub cap 200 is biased by using a biasing mechanism 216 such as a spring so as to be pressed against the print surface of the recording head 50. The urging mechanism 216 is shown only in FIG. 10, and is omitted in FIGS.

  A sub cap drive mechanism (not shown) that rotates the rotation shaft 202 is provided to release capping at the second capping position. The sub-cap driving mechanism includes a motor serving as a driving force source, a coupling (coupling means) for coupling the rotating shaft and the motor, and the like.

  The second moving mechanism for moving the recording head 50 to the second capping position is provided with a solenoid 210 that operates when an abnormal state occurs or when the power is turned off, and a solenoid 210 is provided at one end, and responds to the operation of the solenoid 210. The recording head support member 214 rotates about the rotation shaft 212, and the recording head support member drive mechanism (not shown) that rotates the rotation shaft 212 is provided.

  Further, the recording head 50 is engaged with the other end of the recording head support member 214 so as to be rotatable by a rotation shaft 212, and the recording head support member 214 is biased in the direction indicated by L by the biasing mechanism 216. Has been.

  In FIG. 10, the solenoid 210 is activated (turned on), the recording head support member 214 is held by the operating element 220 by the electromagnetic force of the solenoid 210, and the recording head 50 is held at the capping position using the main cap 53. Is shown.

  11 to 14 show how the recording head 50 moves to the second capping position.

  FIG. 11 shows a state where capping by the main cap 53 is released from the state shown in FIG. When the solenoid 210 is turned off in this state, the operating element 220 moves in the direction indicated by M in FIG. 12, and the holding of the recording head support member 214 is released.

  When the holding of the recording head support member 214 is released, the urging mechanism 216 shown in FIG. 10 provided in the recording head support member 214 operates by elastic deformation using the urging force of the urging mechanism. The support member 214 is rotated in the clockwise direction. As a result, the recording head 50 is moved in the direction indicated by N in FIG.

  As shown in FIG. 14, when the recording head 50 is pressed against the end of the V-shaped arm 204 opposite to the end where the sub cap 200 is attached, the rotating shaft 202 rotates clockwise. The sub cap 200 is pressed against the printing surface of the recording head 50, and capping using the sub cap 200 is performed reliably.

  That is, when an abnormal state such as a jam occurs, the recording head 50 is moved to the second capping position by the force due to the elastic deformation of the biasing mechanism 216, and further capped using the sub cap 200 by the force due to the elastic deformation. .

  When the recording head 50 is moved to the second capping position in an abnormal state, the driving mechanism is cut and the driving head is cut to move the recording head 50 by a force (restoring force of a spring or the like) due to the elastic deformation. Is required. As the drive cutting means, an electromagnetic clutch 230, a one-way clutch or the like shown in FIG. 15 is used. Although not shown in FIG. 15, a driving unit including a motor and a driving mechanism for rotating the rotating shaft 212 to move the recording head 50 to the printing position is provided.

  That is, the electromagnetic clutch 230 is provided in the middle of driving of the rotary shaft 212, and when the recording head 50 is moved to the second capping, the electromagnetic clutch 230 is turned off and the recording head 50 is used by the above-described elastic deformation force. It is comprised so that it may drive.

  Similar to the recording head 50, the rotating shaft 202 of the subcap 200 is also provided with an electromagnetic clutch 232. In the capping operation, the electromagnetic clutch 232 is turned off and the subcap 200 is moved by an elastic force so that the recording head 50 is moved to the printing position. When returning, the electromagnetic clutch 232 is turned on, and the sub cap 200 is moved to a predetermined retracted position by a driving force of a motor or the like.

  Further, when the abnormal state is released, the recording head 50 is initialized, and the rotating shaft 202 is rotated counterclockwise by the driving mechanism of the rotating shaft 202 as shown in FIG. The used capping is released, and the rotation shaft 212 is rotated counterclockwise using the drive mechanism of the rotation shaft 212.

  Here, since the recording head 50 is structured to rotate with respect to the recording head indicating member 214, the position of the recording head 50 at the print position shown in FIG. It is necessary to fix the rotating shaft 216 to ensure accuracy.

  That is, when the recording head 50 is returned to the printing position after being avoided at the second capping position, the positional accuracy of the head surface of the recording head 50 is restricted. In addition, the clearance between the recording head 50 and the conveyance surface is also regulated within a certain range.

  When the recording head 50 is moved from the second capping position to the printing position, the recording head position, horizontality, and conveyance surface of the recording head 50 are adjusted by a recording head position correction member 236 provided in the ink jet recording apparatus main body or the recording head 50. The clearance is within a predetermined range.

  The recording head position correcting member 236 is installed at a position that does not hinder recording paper conveyance and printing. As shown in FIGS. 17 and 18, the recording head position correction member 236 may be in contact with the nozzle surface to obtain a predetermined positional accuracy, or may be in contact with the side surface of the recording head 50. A correction member activation mechanism that moves the recording head position correction member 236 may be provided, and the recording head position correction member 236 may be moved with respect to the fixed recording head 50.

  When the recording head 50 is moved to the printing position, the solenoid 210 is turned on, and the recording head support member 214 is held by the operating element 220.

  When the recording head 50 is held at the print position, capping is performed using the main cap 53, and the recording head 50 is subjected to a recovery operation such as purge or suction.

  With the above configuration, capping is automatically performed using the subcap 200 even when the power is normally turned off.

  That is, when the power is turned off, the solenoid 210 is turned off, and the holding of the recording head support member 214 is released. Therefore, the recording head 50 is automatically moved to the second capping position, and further automatically the subcap. 200 is used for capping.

  When the power is turned on, the capping using the sub-cap 200 is released by the initialization operation of the recording head 50, the recording head 50 is moved to the printing position, and printing can be performed when a predetermined recovery operation is completed.

  After the printing is completed, capping is performed using the main cap 53 to prevent drying of ink during printing standby and the printing surface is protected. When the power is turned off, capping is performed using the sub cap 200.

  In the control system of the inkjet recording apparatus 10 shown in FIG. 4, the solenoid 210 corresponds to the driver 92 and the second moving mechanism corresponds to the head moving mechanism 90. That is, when the power is shut off, the solenoid 210 operates in response thereto, the recording head 50 is moved using the urging force of the urging mechanism 216, and is sent from the system controller 72 when returning to the recording position. In response to the command signal, the rotation shaft 202 and the rotation shaft 212 are rotated by a motor or the like (not shown), and the recording head 50 returns to the recording position. When the recording head 50 returns to the recording position, the solenoid 210 operates in response to a command signal sent from the system controller 72, and the recording head 50 is held at the recording position.

  Although not shown in FIG. 4, the head moving mechanism 90 corresponds to a head holding mechanism, and the driver 92 has a control mechanism corresponding to a solenoid 210.

  Next, a modification of the second embodiment will be described with reference to FIGS.

  As shown in FIG. 19, when a jam occurs, the jammed recording paper 16 may stick to the print surface of the recording head 50. The recording paper 16 attached to the printing surface of the recording head 50 may be peeled off when the recording head 50 is retracted upward. However, if capping is performed without the attached recording paper 16 being peeled off, the recording head 50 is removed. The recording paper 16 is sandwiched between the printing surface and the sub-cap 200, and the recording paper 16 is not capped in a good state, and the recording surface 16 may damage the printing surface and nozzles of the recording head 50. .

  In order to avoid such a state, when the recording head 50 is retracted to the second capping position, the sub-cap 200 is provided with a sub-cap 200 for reliably removing the recording paper 16 attached to the recording surface of the recording head 50. A recording paper removing means (arm) 240 is provided.

  The arm 240 is provided on the opposite side of the rotation axis 202 of the subcap 200, and as shown in FIG. 20, the tip has a pointed shape so that the recording paper 16 can be reliably captured. The arm 240 shown in FIG. 19 is merely an example, and various methods can be applied, such as a mode in which an adhesive member is attached to the leading end, a mode in which static electricity generating means is provided at the leading end, and the recording paper 16 is captured by static electricity. It is.

  FIG. 20 shows a state in which the recording paper 16 attached to the recording head 50 is captured and peeled off from the recording head 50 while the recording head 50 is moved from the print position to the second capping position.

  FIG. 21 shows a state where the recording paper 16 attached to the recording head 50 is peeled off and the recording head 50 is capped by the subcap 200.

  In the ink jet recording apparatus configured as described above, in addition to the main cap 53 that performs capping by moving the recording head 50 to a predetermined position, a sub that can be capped on the recording head 50 by using a non-electrically moving means. The cap 200 is provided so that capping is performed with one of the sub caps 200 when an abnormal condition such as a jam occurs or when the power is turned off, so that capping is ensured not only when a jam occurs but also during an abnormal condition such as an unexpected power interruption. Is performed to prevent thickening (drying) of the ink and protect the printing surface.

  Note that it is preferable to include an arm 240 that is a recording paper removing unit that can reliably remove the recording paper 16 attached to the printing surface of the recording head 50.

  The scope of application of the present invention is not limited to an ink jet recording apparatus, and can be applied to a liquid discharge apparatus that discharges liquids such as water, chemicals, and processing liquid from discharge holes (nozzles) provided in a head.

1 is a basic configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. Block diagram showing an example of the structure of a recording head Plane perspective view showing structure example of recording head Main part block diagram which shows the system configuration | structure of the inkjet recording device which concerns on this embodiment. The figure explaining the recording paper position detection in the inkjet recording device which concerns on this embodiment Diagram for explaining the control of the print head when an abnormal condition occurs The figure explaining arrangement | positioning of the recording paper detection sensor provided in the recording head Diagram for explaining the position detection Diagram explaining capping detection The figure explaining the cap which concerns on 2nd Embodiment of this invention. The figure explaining the capping using the cap shown in FIG. The figure explaining the behavior at the time of solenoid OFF in the capping shown in FIG. The figure explaining the behavior of the recording head in the capping shown in FIG. The figure which shows the time of the capping completion using the cap shown in FIG. The figure explaining the electromagnetic clutch with which the recording head was equipped The figure explaining the electromagnetic clutch with which the cap shown in FIG. 10 was equipped. The figure explaining the correction member which regulates the position accuracy of the recording head in a printing position FIG. 17 is a diagram illustrating a state in which the recording head is aligned using the correction member illustrated in FIG. The figure explaining the modification of 2nd Embodiment of this invention The figure explaining the removal of the recording paper in the modification of 2nd Embodiment of this invention The figure which shows the time of the completion of capping in the modification of 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 12 ... Printing part, 50 ... Recording head, 51, 52, 100, 102, 104, 110, 112, 114 ... Recording paper detection sensor, 53, 200 ... Cap, 54 ... Nozzle, 72 ... System Controllers 120, 122 ... light shielding plate, 216 ... biasing mechanism, 240 ... recording paper removing means

Claims (10)

Recording means having a plurality of line-type recording heads in which a plurality of recording elements are arranged in the width direction of the recording medium;
Conveying means for relatively moving at least one of the recording medium and the recording means in a direction substantially perpendicular to the width direction of the recording medium;
Detection means provided on the upstream and downstream sides of each recording head in the relative conveyance direction of the recording medium, and detecting the recording medium when the recording head is at a predetermined recording position;
Recording head movement drive means for moving the recording head from the recording position to a predetermined retracted position;
When the relative conveyance of the recording medium is interrupted, control is performed so that the recording head in the recording means is selectively moved to a predetermined retraction position according to the position of the recording medium detected by the detection means. Recording head control means,
An image forming apparatus comprising: A recording surface sealing means mounted so as to cover the recording surface of the recording head;
The recording head control means controls the recording surface sealing means to be mounted on the recording surface of the recording head that is not moved by the recording head movement driving means when the relative conveyance of the recording medium is interrupted. The image forming apparatus according to claim 1.   The detection means has a plurality of detectors on the upstream side and the downstream side in the relative transport direction of the recording medium of each recording head, and the detector is in a direction substantially orthogonal to the relative transport direction of the recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed along a position corresponding to a width of the recording medium along the recording medium.   4. The image forming apparatus according to claim 2, wherein the recording surface sealing unit includes a detected unit that can be detected by the detector arranged at a diagonal position of the recording head.   The image forming apparatus according to claim 1, wherein the detection unit is configured integrally with the recording head.   6. The recording head moving drive unit according to claim 1, further comprising a mechanism for moving the recording head by elastic deformation generated when releasing a force for biasing the recording head in a predetermined direction. The image forming apparatus according to any one of the above.   The image according to any one of claims 1 to 6, further comprising a recording surface sealing means for retracting that is mounted so as to cover a recording surface of the recording head at the retracted position of the recording head. Forming equipment.   8. The image forming apparatus according to claim 1, further comprising a recording medium peeling unit that peels off the recording medium attached to the recording surface of the recording head. Recording means having a plurality of full-line type recording heads in which a plurality of recording elements are arranged on the recording surface over a length corresponding to the printable width of the recording medium, and at least one of the recording medium and the recording means A recording head control method for an image recording apparatus, comprising: conveying means for relatively moving one side in a direction substantially orthogonal to the width direction of the recording medium,
A transport step of relatively transporting the recording medium by the transport means;
In the transport process, the recording medium when each recording head is at a predetermined recording position is detected using detection means provided on the upstream side and the downstream side in the recording medium relative transport direction of each recording head. The detection process;
When the relative conveyance of the recording medium by the conveying means is interrupted, a retreating step for retreating the recording head corresponding to the detection position of the recording medium by the detection step to a predetermined retraction position;
A recording head control method.   The recording head control method according to claim 9, further comprising a maintenance step of performing maintenance of the recording head that has been retracted to a predetermined retracted position by the retracting step.

Images