JP5276558B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can perform highly accurate temperature detection using a non-contact type temperature detection device and keeps it maintenance-free. <P>SOLUTION: A plurality of suction holes (220) are provided at the outer peripheral surface of a drawing drum 44. Suction pressure to suck a recording medium (14) is generated in suction holes in drawing areas immediately under inkjet heads 48Y, 48C, 48K and 48M. After the recording medium is delivered to a delivery drum 52, air is blown out from the suction hole so that ink mist or the like stuck in the suction hole may be discharged, and then a light receiving surface of a temperature sensor 206 is cleaned by a cleaning wind blown to the light receiving surface of the temperature sensor 206 from the suction hole. An existing constitution is utilized for a constitution to blow the cleaning wind to the light receiving surface and a constitution to switch the suction and the discharge. The cleaning of the light receiving surface is automatically carried out while the drawing drum 44 is operated. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly, to a maintenance technique for a temperature detection apparatus that detects the temperature of a medium transport member that transports a recording medium.

  In an image forming apparatus such as an electrophotographic apparatus, it is indispensable to include a temperature detection device in order to control the temperature of a conveyance drum that conveys a recording medium. Conventionally, contact-type temperature detection devices such as thermistors have been used, but problems such as detection performance deterioration due to dirt or scratches on the detection surface due to sliding with the transport drum, and wear due to sliding As a result, there has been a problem that the lifetime of the detection element is shortened. In recent years, a non-contact type temperature detecting device using a thermopile has been used as a non-contact type sensor that detects the amount of infrared rays emitted from the object to be measured.

  Patent Document 1 discloses that an electrophotographic image forming apparatus to which a thermopile type temperature sensor is applied as a means for detecting the surface temperature of a photoconductor in a non-contact manner needs to include cleaning of a lens positioned at a detection portion of the sensor. Even if the lens is soiled by paper dust or toner without sufficient maintenance, and the amount of infrared rays transmitted through the lens decreases and the detected temperature shifts to the lower side, the temperature on the surface of the photoconductor is reduced. A temperature control technique for controlling the temperature to about 35 to 45 ° C. is disclosed.

JP 2006-301012 A

  However, the temperature control of the printing drum of an inkjet printer used in commercial printing requires an accuracy of about ± 1 ° C. in consideration of the dot diameter variation formed on the recording medium. Insufficient accuracy. In addition, since inkjet printers for commercial printing use are extremely high in productivity and usage frequency compared to home printers and office printers, a large amount of paper dust and dust are generated.

  In an inkjet printer used for commercial printing, in order to perform high-precision temperature control using a non-contact type temperature detection device, the light receiving surface of the temperature detection device is frequently cleaned to ensure temperature detection accuracy. There is a need. However, in order to clean the light receiving surface of the temperature detection device, it is necessary to stop the device, and there is a concern that productivity may be reduced due to frequent cleaning. However, it is not desirable to stop the device as much as possible from the viewpoint of ensuring a certain productivity. In addition, a countermeasure for providing a temperature-detecting device with a dust-proof cover with an air blow is conceivable, but a compressor for blowing air to the light receiving surface must be prepared. Furthermore, depending on the configuration of the conveying member, it may be impossible to secure an appropriate installation location for the dust cover.

  The present invention has been made in view of such circumstances, and an image that appropriately performs maintenance of the temperature detection device provided in association with the medium transport unit and enables maintenance-free operation of the temperature detection device. An object is to provide a forming apparatus.

In order to achieve the above object, an image forming apparatus according to the present invention includes a conveyance unit that holds a recording medium and conveys the recording medium in a predetermined direction, a temperature detection unit that detects the temperature of the conveyance unit in a non-contact manner, And a cleaning unit that applies cleaning air to the temperature detection unit of the temperature detection unit from the transport unit to remove deposits attached to the temperature detection unit, and the transport unit holds a recording medium. It has a structure in which a suction hole for generating a suction pressure is provided on the medium holding surface, and the cleaning means includes a cleaning air jetting means for jetting cleaning air from the suction hole .

According to the present invention, since the cleaning air is applied from the conveying means to the temperature detecting portion of the temperature detecting means, the temperature detecting portion is maintained in a clean state and preferable temperature control is possible. Moreover, it is possible to clean the temperature detection unit using an existing configuration without providing a dedicated injection nozzle or the like for cleaning the temperature detection unit.

1 is an overall configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. Plane perspective view showing a configuration example of an inkjet head Partial enlarged view of the inkjet head shown in FIG. Plane perspective view showing another configuration example of the inkjet head shown in FIG. Plane perspective view showing still another configuration example of the inkjet head shown in FIG. Sectional drawing which follows the AA line in FIG. Main block diagram showing the system configuration of the inkjet recording apparatus Schematic configuration diagram showing the configuration around the drawing unit according to the first embodiment The block diagram which shows the example of arrangement | positioning of the heater shown in FIG. The block diagram which shows the example of arrangement | positioning of the temperature sensor shown in FIG. FIG. 8 is an exploded perspective view of the drawing drum shown in FIG. Schematic configuration diagram showing the configuration around the drawing unit according to the second embodiment The top view which shows the planar shape of the duct shown in FIG.

  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 a configuration diagram showing the overall configuration of the ink jet recording apparatus according to the present embodiment. The ink jet recording apparatus 10 shown in the figure forms an image on the recording surface of the recording medium 14 based on predetermined image data using an ink containing a color material and an aggregating treatment liquid having a function of aggregating the ink. This is a two-liquid aggregation type recording apparatus.

  The ink jet recording apparatus 10 mainly includes a paper supply unit 20, a treatment liquid application unit 30, a drawing unit 40, a drying processing unit 50, a fixing processing unit 60, and a discharge unit 70. Transfer cylinders 32, 42, 52, and 62 are provided as means for delivering the recording medium 14 conveyed upstream of the treatment liquid application unit 30, the drawing unit 40, the drying processing unit 50, and the fixing processing unit 60, and the treatment liquid. As means for conveying the recording medium 14 while holding the recording medium 14 in each of the coating unit 30, the drawing unit 40, the drying processing unit 50, and the fixing processing unit 60, impression cylinders 34, 44, 54, and 64 having a drum shape are provided. .

  The transfer cylinders 32, 42, 52, 62 and the impression cylinders 34, 44, 54, 64 are provided with grippers 80 </ b> A, 80 </ b> B that hold the leading end portion of the recording medium 14 at predetermined positions on the outer peripheral surface. The gripper 80A and the gripper 80B have the same structure for holding the leading end portion of the recording medium 14 between them, and the structure for transferring the recording medium 14 to / from a gripper provided on another impression cylinder or transfer cylinder, and The gripper 80 </ b> A and the gripper 80 </ b> B are arranged at symmetrical positions that are moved 180 ° in the rotation direction of the pressure drum 34 on the outer peripheral surface of the pressure drum 34.

  When the transfer cylinders 32-62 and the impression cylinders 34, 44, 54, 64 are rotated in a predetermined direction with the gripper 80A, 80B holding the leading end of the recording medium 14, the transfer cylinders 32-62 and the impression cylinder 34 are rotated. , 44, 54, 64, the recording medium 14 is rotated and conveyed along the outer peripheral surface.

  In FIG. 1, only the grippers 80 </ b> A and 80 </ b> B provided in the impression cylinder 34 are denoted by reference numerals, and the reference numerals of the other impression cylinders and the transfer cylinder grippers are omitted.

  When the recording medium (sheet) 14 accommodated in the paper supply unit 20 is fed to the treatment liquid application unit 30, the aggregation process is performed on the recording surface of the recording medium 14 held on the outer peripheral surface of the impression cylinder 34. A liquid (hereinafter simply referred to as “treatment liquid”) is applied. The “recording surface of the recording medium 14” is an outer surface in a state where the impression cylinders 34, 44, 54, 64 are held, and is a surface opposite to the surface held by the impression cylinders 34, 44, 54, 64. It is.

  Thereafter, the recording medium 14 to which the aggregation treatment liquid has been applied is sent to the drawing unit 40, and color ink is applied to the area of the recording surface to which the aggregation treatment liquid has been applied, thereby forming a desired image.

  Further, the recording medium 14 on which the image of the color ink is formed is sent to the drying processing unit 50, where the drying processing unit 50 performs the drying processing, and after the drying processing, the recording medium 14 is sent to the fixing processing unit 60 to perform the fixing processing. Applied. By performing the drying process and the fixing process, the image formed on the recording medium 14 is hardened. In this way, a desired image is formed on the recording surface of the recording medium 14, and after the image is fixed on the recording surface of the recording medium 14, it is conveyed from the discharge unit 70 to the outside of the apparatus.

  Hereinafter, each part (the paper feeding unit 20, the processing liquid coating unit 30, the drawing unit 40, the drying processing unit 50, the fixing processing unit 60, and the discharging unit 70) of the inkjet recording apparatus 10 will be described in detail.

(Paper Feeder)
The paper feeding unit 20 is provided with a paper feeding tray 22 and a feeding mechanism (not shown), and the recording medium 14 is configured to be fed one by one from the paper feeding tray 22. The recording medium 14 sent out from the paper feed tray 22 is positioned by a guide member (not shown) so as to be positioned at a position of a gripper (not shown) of the transfer drum (paper feed drum) 32 and temporarily stops.

(Processing liquid application part)
The processing liquid application unit 30 includes a pressure drum (processing liquid drum) 34 that holds the recording medium 14 delivered from the paper feeding cylinder 32 on the outer peripheral surface and conveys the recording medium 14 in a predetermined conveying direction, and a processing liquid drum. And a processing liquid coating device 36 for applying a processing liquid to the recording surface of the recording medium 14 held on the outer peripheral surface 34 of the recording medium 14. When the processing liquid drum 34 is rotated counterclockwise in FIG. 1, the recording medium 14 is rotated and conveyed in the counterclockwise direction along the outer peripheral surface of the processing liquid drum 34.

  In addition, there is provided an application roller moving mechanism that moves the application roller in the vertical direction (the normal direction of the outer peripheral surface of the treatment liquid drum 34), and an aspect in which collision between the application roller and the grippers 80A and 80B can be avoided. preferable.

  The processing liquid applied to the recording medium 14 by the processing liquid coating apparatus 36 contains a color material flocculant that aggregates the color material (pigment) in the ink applied by the drawing unit 40, and the processing liquid is applied on the recording medium 14. And the ink come into contact with each other, the separation of the color material and the solvent in the ink is promoted.

  The treatment liquid application unit 30 is preferably applied while measuring the amount of the treatment liquid applied to the recording medium 14, and the film thickness of the treatment liquid on the recording medium 14 is determined by the ink droplets ejected from the drawing unit 40. It is preferable to make it sufficiently smaller than the diameter.

(Drawing part)
The drawing unit 40 holds an impression cylinder (drawing drum) 44 that holds and transports the recording medium 14, a sheet pressing roller 46 for bringing the recording medium 14 into close contact with the drawing drum 44, and an inkjet that applies ink to the recording medium 14. Heads 48M, 48K, 48C, and 48Y are provided. The basic structure of the drawing drum 44 is the same as that of the processing liquid drum 34 described above, and a description thereof is omitted here.

  The sheet pressing roller 46 is a guide member for bringing the recording medium 14 into close contact with the outer peripheral surface of the drawing drum 44, faces the outer peripheral surface of the drawing drum 44, and delivers the recording medium 14 between the transfer drum 42 and the drawing drum 44. It is disposed downstream of the position in the transport direction of the recording medium 14 and upstream of the ink jet heads 48M, 48K, 48C, and 48Y in the transport direction of the recording medium 14.

  The recording medium 14 transferred from the transfer drum 42 to the drawing drum 44 is pressed by the sheet holding roller 46 when being rotated and conveyed with the leading end held by a gripper (reference numeral omitted), and the outer periphery of the drawing drum 44. Adhere to the surface. After the recording medium 14 is brought into close contact with the outer peripheral surface of the drawing drum 44 in this way, the recording medium 14 is sent to the print area immediately below the ink jet heads 48M, 48K, 48C, 48Y without being lifted from the outer peripheral surface of the drawing drum 44. It is done.

  The inkjet heads 48M, 48K, 48C, and 48Y correspond to inks of four colors, magenta (M), black (K), cyan (C), and yellow (Y), respectively, and the rotation direction of the drawing drum 44 (see FIG. 1 are arranged in order from the upstream side in the counterclockwise direction in FIG. 1, and the ink discharge surfaces (nozzle surfaces, denoted by reference numeral 100A in FIG. 2) of the ink jet heads 48M, 48K, 48C, and 48Y are illustrated in the drawing drum. The recording medium 14 is held so as to face the recording surface of the recording medium 14. The “ink ejection surface (nozzle surface)” is a surface of the inkjet heads 48M, 48K, 48C, and 48Y that faces the recording surface of the recording medium 14, and is a nozzle (not shown in FIG. This is the surface on which the reference numeral 102 is shown in FIG.

  Further, in the inkjet heads 48M, 48K, 48C, 48Y shown in FIG. 1, the recording surface of the recording medium 14 held on the outer peripheral surface of the drawing drum 44 and the nozzle surfaces of the inkjet heads 48M, 48K, 48C, 48Y are substantially parallel. In such a manner, it is arranged to be inclined with respect to the horizontal plane.

  The inkjet heads 48M, 48K, 48C, and 48Y are full-line heads having a length corresponding to the maximum width of the image forming area in the recording medium 14 (the length in the direction orthogonal to the conveyance direction of the recording medium 14). The recording medium 14 is fixedly installed so as to extend in a direction orthogonal to the conveyance direction of the recording medium 14.

  On the nozzle surfaces (liquid ejection surfaces) of the inkjet heads 48M, 48K, 48C, and 48Y, ink ejection nozzles are formed in a matrix arrangement over the entire width of the image forming area of the recording medium 14.

  When the recording medium 14 is conveyed to the printing area immediately below the ink jet heads 48M, 48K, 48C, 48Y, the image data is converted into the area where the aggregation processing liquid of the recording medium 14 is applied from the ink jet heads 48M, 48K, 48C, 48Y. Based on this, ink of each color is ejected (droplet ejection).

  When droplets of the corresponding color ink are ejected from the inkjet heads 48M, 48K, 48C, and 48Y toward the recording surface of the recording medium 14 held on the outer peripheral surface of the drawing drum 44, processing is performed on the recording medium 14. The liquid and the ink come into contact with each other, and an aggregation reaction of the color material (pigment-based color material) dispersed in the ink or the color material (dye-based color material) to be insolubilized appears, and a color material aggregate is formed. As a result, movement of the color material in the image formed on the recording medium 14 (dot misalignment, dot color unevenness) is prevented.

  In addition, since the drawing drum 44 of the drawing unit 40 is structurally separated from the processing liquid drum 34 of the processing liquid application unit 30, the processing liquid does not adhere to the ink jet heads 48M, 48K, 48C, and 48Y. In addition, the cause of abnormal ink ejection can be reduced.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special colors are used as necessary. Ink may be added. For example, it is possible to add an inkjet head that discharges light-colored ink such as light cyan and light magenta, and the arrangement order of the color heads is not particularly limited.

Although details will be described later, the ink jet recording apparatus 10 shown in this example includes a heater for heating the surface of the drawing drum 44 (not shown in FIG. 1 , indicated by reference numeral 204 in FIG. 8 ) , and drawing. A non-contact temperature sensor for detecting the surface temperature of the drum 44 (not shown in FIG. 1, illustrated with reference numeral 206 in FIG. 8), and cleaning air is applied to the detection portion of the temperature sensor. A cleaning function is provided. Based on the detection result by the temperature sensor, the heater is controlled so that the change in the surface temperature of the drawing drum 44 does not exceed a certain range.

(Dry processing part)
The drying processing unit 50 holds an impression cylinder (drying drum) 54 that holds and conveys the recording medium 14 after image formation, and a drying processing device 56 that performs a drying process for evaporating moisture (liquid component) on the recording medium 14. It has. The basic structure of the drying drum 54 is the same as that of the processing liquid drum 34 and the drawing drum 44 described above, and a description thereof is omitted here.

  The drying processing device 56 is a processing unit that is disposed at a position facing the outer peripheral surface of the drying drum 54 and evaporates moisture present in the recording medium 14. When ink is applied to the recording medium 14 by the drawing unit 40, the liquid component (solvent component) of the ink and the liquid component (solvent component) of the processing liquid separated by the aggregation reaction between the processing liquid and the ink are placed on the recording medium 14. Since it remains, it is necessary to remove such a liquid component.

  The drying processing device 56 performs a drying process for evaporating a liquid component existing on the recording medium 14 by heating with a heater, blowing with a fan, or a combination thereof, and a process for removing the liquid component on the recording medium 14. Part. The amount of heating and the amount of air supplied to the recording medium 14 are appropriately set according to parameters such as the amount of moisture remaining on the recording medium 14, the type of the recording medium 14, and the conveyance speed (interference processing time) of the recording medium 14. Is done.

  When the drying processing by the drying processing device 56 is performed, the drying drum 54 of the drying processing unit 50 is structurally separated from the drawing drum 44 of the drawing unit 40, and therefore, the inkjet heads 48M, 48K, 48C, 48Y. In this case, it is possible to reduce the cause of abnormal ink ejection due to drying of the head meniscus by heat or air blowing.

  In order to exhibit the cockling correction effect of the recording medium 14, the curvature of the drying drum 54 is preferably 0.002 (1 / mm) or more. Further, in order to prevent the recording medium from being curved (curled) after the drying process, the curvature of the drying drum 54 is preferably 0.0033 (1 / mm) or less.

  In addition, a means (for example, a built-in heater) for adjusting the surface temperature of the drying drum 54 may be provided, and the surface temperature may be adjusted to 50 ° C. or higher. By applying heat treatment from the back surface of the recording medium 14, drying is promoted and image destruction during the subsequent fixing process is prevented. In this embodiment, it is more effective to provide means for bringing the recording medium 14 into close contact with the outer peripheral surface of the drying drum 54. Examples of the means for bringing the recording medium 14 into close contact include vacuum suction and electrostatic suction.

  The upper limit of the surface temperature of the drying drum 54 is not particularly limited, but from the viewpoint of safety of maintenance work such as cleaning ink adhering to the surface of the drying drum 54 (preventing burns due to high temperature). It is preferably set to 75 ° C. or lower (more preferably 60 ° C. or lower).

  The recording drum 14 is held on the outer peripheral surface of the drying drum 54 configured in this manner so that the recording surface of the recording medium 14 faces outward (that is, in a state in which the recording surface of the recording medium 14 is convex). By performing the drying process while rotating and transporting, drying unevenness due to wrinkling and floating of the recording medium 14 is surely prevented.

(Fixing processing part)
The fixing processing unit 60 includes a pressure drum (fixing drum) 64 that holds and conveys the recording medium 14, a heater 66 that heats the recording medium 14 on which an image is formed and liquid is removed, and the recording And a fixing roller 68 that presses the medium 14 from the recording surface side. Since the basic structure of the fixing drum 64 is common to the processing liquid drum 34, the drawing drum 44, and the drying drum 54, description thereof is omitted here. The heater 66 and the fixing roller 68 are disposed at a position facing the outer peripheral surface of the fixing drum 64, and are sequentially disposed from the upstream side in the rotation direction of the fixing drum 64 (counterclockwise direction in FIG. 1).

  In the fixing processing unit 60, the recording surface of the recording medium 14 is subjected to a preheating process by the heater 66 and a fixing process by the fixing roller 68. The heating temperature of the heater 66 is appropriately set according to the type of recording medium, the type of ink (the type of polymer fine particles contained in the ink), and the like. For example, a mode in which the glass transition temperature and the minimum film forming temperature of the polymer fine particles contained in the ink are considered.

  The fixing roller 68 is a roller member for heating and pressurizing the dried ink to weld the self-dispersing polymer fine particles in the ink to form a film of the ink, and is configured to heat and press the recording medium 14. The Specifically, the fixing roller 68 is disposed so as to be in pressure contact with the fixing drum 64, and constitutes a nip roller with the fixing drum 64. As a result, the recording medium 14 is sandwiched between the fixing roller 68 and the fixing drum 64 and nipped at a predetermined nip pressure, and a fixing process is performed.

  As an example of the configuration of the fixing roller 68, there is an embodiment in which the fixing roller 68 is configured by a heating roller in which a halogen lamp is incorporated in a metal pipe such as aluminum having good thermal conductivity. By heating the recording medium 14 with such a heating roller, when thermal energy equal to or higher than the glass transition temperature of the polymer fine particles contained in the ink is applied, the polymer fine particles are melted to form a transparent film on the surface of the image. Is done.

  When pressure is applied to the recording surface of the recording medium 14 in this state, the polymer fine particles melted into the unevenness of the recording medium 14 are pressed and fixed, and the unevenness of the image surface is leveled, so that preferable glossiness can be obtained. A configuration in which a plurality of fixing rollers 68 are provided in accordance with the thickness of the image layer and the glass transition temperature characteristics of the polymer particles is also preferable.

  The surface hardness of the fixing roller 68 is preferably 71 ° or less. By making the surface of the fixing roller 68 softer, a follow-up effect can be expected for the unevenness of the recording medium 14 caused by cockling, and fixing unevenness due to the unevenness of the recording medium 14 can be more effectively prevented. .

  In the ink jet recording apparatus 10 shown in FIG. 1, an inline sensor 82 is provided at a subsequent stage (downstream in the recording medium conveyance direction) of the processing area of the fixing processing unit 60. The in-line sensor 82 is a sensor for reading an image formed on the recording medium 14 (or a check pattern formed in a blank area of the recording medium 14), and a CCD line sensor is preferably used.

  In the ink jet recording apparatus 10 shown in this example, the presence or absence of ejection abnormality of the ink jet heads 48M, 48K, 48C, and 48Y is determined based on the reading result of the inline sensor 82. Further, the in-line sensor 82 may include a measuring unit for measuring the moisture content, the surface temperature, the glossiness, and the like. In such an embodiment, parameters such as the processing temperature of the drying processing unit 50, the heating temperature of the fixing processing unit 60, and the pressure pressure are appropriately adjusted based on the moisture content, surface temperature, and gloss reading result, and the temperature inside the apparatus. The control parameter is adjusted as appropriate in accordance with the change and the temperature change of each part.

(Discharge part)
As shown in FIG. 1, a discharge unit 70 is provided following the fixing processing unit 60. The discharge unit 70 includes an endless conveyance belt 74 wound around the stretching rollers 72A and 72B, and a discharge tray 76 that stores the recording medium 14 after image formation.

The recording medium 14 after the fixing process sent out from the fixing processing unit 60 is transported by the transport belt 74 and discharged to the discharge tray 76 .

[Inkjet head structure]
Next, the structure of the inkjet heads 48M, 48K, 48C, 48Y provided in the drawing unit 40 will be described. Since the structures of the ink jet heads 48M, 48K, 48C, and 48Y corresponding to the respective colors are common, the ink jet head (hereinafter also simply referred to as “head”) is denoted by reference numeral 100 in the following. And

  FIG. 2 is a perspective plan view showing a structural example of the head 100. Hereinafter, in this specification, the same or similar parts as those described above are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 2, the head 100 is a full-line type head having a full width W plurality of nozzles 102 through a length corresponding to _m it is ordered structure of the recording medium 14 to the nozzle face 100A. The conveyance direction S of the recording medium 14 is sometimes referred to as a sub-scanning direction, and the direction M orthogonal to the conveyance direction S of the recording medium 14 is sometimes referred to as a main scanning direction.

In order to increase the dot pitch formed on the recording medium 14, it is necessary to increase the nozzle pitch in the head 100. As shown in FIG. 2, the head 100 of this example includes a nozzle 102 that is an ink discharge port, a pressure chamber 104 that communicates with each nozzle 102, a common channel that is not shown, and a supply that communicates with each pressure chamber 104. It has a structure in which a plurality of ink chamber units (droplet discharge elements as recording element units) 108 including ports 106 and the like are arranged in a matrix, so that they are arranged along the main scanning direction which is the longitudinal direction of the head 100. A high density of the projected nozzle spacing (projection nozzle pitch indicated by the symbol _{Pn in} FIG. 3) is achieved.

  The pressure chamber 104 communicating with the nozzle 102 has a substantially square planar shape, the nozzle 102 is provided at one of the diagonal corners, and the supply port 106 is provided at the other. The shape of the pressure chamber 104 is not limited to this example, and the planar shape may have various forms such as a quadrangle (rhombus, rectangle, etc.), a pentagon, a hexagon and other polygons, a circle, and an ellipse.

  FIG. 3 is an enlarged view of a part of the head 100 shown in FIG. As shown in the figure, the ink chamber unit 108 composed of the nozzles 102, the pressure chambers 104, and the like is arranged at a certain angle that is not orthogonal to the row direction and the main scanning direction along the main scanning direction (shown with reference numeral M). The high-density nozzle head of this example is arranged in a matrix with a fixed arrangement pattern along an oblique column direction (shown with reference numeral S ′) having θ (0 ° <θ <90 °). It has been realized.

That is, the projected nozzle pitch P _{n of} the nozzles projected so as to be aligned in the main scanning direction by a structure in which a plurality of ink chamber units 108 are arranged at a constant pitch d along a direction that forms an angle θ with respect to the main scanning direction. D × cos θ, and in the main scanning direction, each nozzle 102 can be handled equivalently as a linear array with a constant pitch P _n . With such a configuration, it is possible to realize a high-density arrangement of 2400 nozzles per inch (2400 nozzles / inch) that are projected so as to be aligned in the main scanning direction.

Note that mode of forming one or more nozzle rows through a length corresponding to the full width W _m of the recording medium 14 is not limited to this example. For example, instead of the configuration of FIG. 2, as shown in FIG. 4, a short head module 100 ′ in which a plurality of nozzles 102 are two-dimensionally arranged is arranged in a staggered manner and connected to be elongated. Thus, a line head having a nozzle row having a length corresponding to the entire width of the recording medium 14 as a whole may be configured.

  Further, as shown in FIG. 5, a line head may be configured by arranging short head modules 100 ″ that are less than the full width of the recording medium 14 in a line. In the figure, along the line direction (see FIG. 2). The arranged nozzles 102 are shown by oblique solid lines.

  6 is a cross-sectional view (a cross-sectional view taken along the line AA in FIG. 2) showing a three-dimensional structure of the head 100 (ink chamber unit 108) shown in FIG.

  The pressure chamber 104 communicating with the nozzle 102 communicates with the common flow path 110 via the supply port 106. The common channel 110 communicates with an ink tank (not shown) as an ink supply source, and the ink supplied from the ink tank is supplied to each pressure chamber 104 via the common channel 110.

  The vibration plate 112 constituting the upper surface of the pressure chamber 104 includes an individual electrode 114 and a common electrode 116, and a piezoelectric body having a structure in which a piezoelectric body 118 is sandwiched between the individual electrode 114 and the common electrode 116. The element 120 is joined. Further, the head 100 shown in FIG. 6 includes a nozzle plate 124 in which an opening 122 of the nozzle 102 is formed in a structure in which a flow channel structure such as the pressure chamber 104, the supply port 106, and the common flow channel 110 is formed. It has a joined structure.

  By applying a predetermined drive voltage between the individual electrode 114 and the common electrode 116, the piezoelectric element 120 and the diaphragm 112 are deformed, and the volume of the pressure chamber 104 changes accordingly. A pressure change occurs in the ink inside the pressure chamber 104 due to the volume change of the pressure chamber 104, and a volume of ink corresponding to the volume change of the pressure chamber 104 is ejected from the nozzle 102. After the ink is ejected, the pressure chamber 104 is filled with new ink from the common flow path 110 through the supply port 106 when the piezoelectric element 120 and the vibration plate 112 return to the original state.

  In this example, the piezoelectric element 120 is used as a means for generating ink ejection force to be ejected from the nozzles 102 provided in the head 100. However, a heater is provided in the pressure chamber 104 and the pressure of film boiling caused by heating of the heater is used. It is also possible to apply a thermal method that ejects ink.

[Explanation of control system]
FIG. 7 is a block diagram illustrating a schematic configuration of a control system of the inkjet recording apparatus 10. The inkjet recording apparatus 10 includes a communication interface 140, a system control unit 142, a conveyance control unit 144, an image processing unit 146, a head driving unit 148, and a storage unit (memory) 150 and a temporary storage unit 152.

  The communication interface 140 is an interface unit that receives image data sent from the host computer 154. The communication interface 140 may be a serial interface such as USB (Universal Serial Bus) or a parallel interface such as Centronics. The communication interface 140 may include a buffer memory (not shown) for speeding up communication.

  The system control unit 142 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 10 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. Further, it functions as a memory controller for the storage unit 150 and the temporary storage unit 152. That is, the system control unit 142 controls each unit such as the communication interface 140 and the transport control unit 144, performs communication control with the host computer 154, read / write control of the storage unit 150 and the temporary storage unit 152, and the like. A control signal is generated to control each part.

  Image data sent from the host computer 154 is taken into the ink jet recording apparatus 10 via the communication interface 140, and predetermined image processing is performed by the image processing unit 146.

  The image processing unit 146 has a signal (image) processing function for performing various processing and correction processes for generating a print control signal from the image data, and supplies the generated print data to the head drive unit 148. It is a control unit. Necessary signal processing is performed in the image processing unit 146, and the ejection droplet amount (droplet ejection amount) and ejection timing of the head 100 are controlled via the head driving unit 148 based on the image data. Thereby, a desired dot size and dot arrangement are realized. Note that the head driving unit 148 shown in FIG. 7 may include a feedback control system for keeping the driving conditions of the head 100 constant.

  Further, the conveyance control unit 144 controls the conveyance timing and conveyance speed of the recording medium 14 (see FIG. 1) based on the print control signal generated by the image processing unit 146. 7 includes a motor that rotates the impression cylinders 34, 44, 54, and 64 in FIG. 1, a motor that rotates the transfer cylinders 32 to 62, and a motor for the feeding mechanism of the recording medium 14 in the sheet feeding unit 20. In addition, a motor for driving the stretching roller 72A (72B) of the discharge unit 70 is included, and the conveyance control unit 144 functions as a driver for the motor.

  The storage unit 150 stores a program executed by the CPU of the system control unit 142, various data necessary for control of each unit of the apparatus, control parameters, and the like, and data is read and written through the system control unit 142. The storage unit 150 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used. Alternatively, a removable storage medium that includes an external interface may be used.

  The temporary storage unit (temporary storage memory) 152 functions as a temporary storage unit that temporarily stores image data input via the communication interface 140, a development area for various programs stored in the storage unit 150, and a CPU. It has a function as a calculation work area (for example, a work area of the image processing unit 146). As the temporary storage unit 152, a volatile memory (RAM) capable of sequential reading and writing is used.

  Further, the inkjet recording apparatus 10 includes a processing liquid application control unit 160, a drying processing control unit 162, and a fixing processing control unit 164, and in accordance with instructions from the system control unit 142, the processing liquid application unit 30 is provided. The operation of each part of the fixing processing unit 60 including the drying processing unit 50, the heater 66, and the fixing roller 68 (see FIG. 1) is controlled.

  Based on the print data obtained from the image processing unit 146, the processing liquid application control unit 160 controls the processing liquid application timing and also controls the application amount of the processing liquid.

  The drying process control unit 162 controls the timing of the drying process and also controls the processing temperature, the air flow rate, and the like, and the fixing process control unit 164 controls the temperature of the heater 66 and the pressing of the fixing roller 68. .

  The detection unit 166 is a processing block including the inline sensor 82 illustrated in FIG. 1 and a signal processing unit that performs predetermined signal processing such as nozzle removal, amplification, and waveform shaping on the read signal output from the inline sensor 82. Based on the detection signal obtained by the detection unit 166, the system control unit 142 determines whether there is an ejection abnormality of the head 100.

  The temperature detection unit 168 illustrated in FIG. 7 includes a plurality of temperature sensors provided in each part of the inkjet recording apparatus 10 such as temperature sensors that detect the surface temperature of the impression cylinders 34, 44, 54, and 64. ing. For example, the temperature detection unit 168 in FIG. 7 includes a temperature sensor 206 that detects the surface temperature of the impression cylinder (drawing drum) 44 illustrated in FIG.

  The temperature information obtained from the temperature detection unit 168 is sent to the system control unit 142, and the system control unit 142 stores the temperature information of each part of the device obtained from the temperature detection unit 168 in a predetermined storage unit as necessary. Then, a command signal is sent to the temperature control unit of each part of the apparatus. In the ink jet recording apparatus 10 shown in this example, as a temperature control unit, a heater control unit 170 and a cooling control unit (not shown in FIG. 7 and illustrated with reference numeral 402 in FIG. 12) are controlled. (Not shown).

  The heater control unit 170 is one of the temperature control units of each unit described above, and controls the heater 172 based on a command signal sent from the system control unit 142. The heater 172 shown in FIG. 7 heats the surface of the impression cylinders 34, 44, 54, 64 (halogen lamp, shown with reference numeral 204 in FIG. 8) and ink in the ink jet head. A heater, a heating device, and the like provided in each part of the apparatus such as a heater are included.

  Based on the command signal sent from the system control unit 142, the valve control unit 174 generates a control signal for performing opening / closing control and switching control of the control valve 176 provided in the flow path (pipe) of liquid or air. A control signal is sent to each control valve. The control valve 176 illustrated in FIG. 7 includes a valve (electromagnetic valve) for opening and closing an air flow path disposed in the pressure drums 34, 44, 54, and 64, a valve for switching the flow path, and the like. Yes.

  Based on the command signal sent from the system control unit 142, the pump control unit 178 generates a control signal for performing on / off control of the pump 180 and switching of the rotation direction (switching of pressurization / depressurization). The control signal generated by the pump control unit 178 is sent to a pump for generating an adsorption pressure for adsorbing the recording medium, a pump for performing maintenance of the inkjet heads 48M, 48K, 48C, and 48Y.

[First Embodiment, Description of Configuration for Cleaning Temperature Sensor]
Next, a configuration for cleaning the temperature sensor 206 that detects the surface temperature of the impression cylinder (drawing drum) 44 applied to the drawing unit 40 illustrated in FIG. 1 will be described in detail.

  FIG. 8 is a schematic configuration diagram around the drawing unit 40 extracted from FIG. 1 and the configuration around the drawing unit 40. Here, the description of the configuration already described with reference to FIG. 1 is omitted. Further, in FIG. 8, illustration of a part of the members illustrated in FIG. 1 is omitted.

  As shown in FIG. 8, the recording medium (shown with reference numeral 14 in FIG. 1) transferred from the transfer drum 42 to the drawing drum 44 is attracted and held on the outer peripheral surface of the drawing drum 44. 8 is a suction holding area in which the recording medium is sucked and held in the conveyance path of the recording medium. The area indicated by the arrow line pointing inward from the outer peripheral surface of the drawing drum 44 (the upper half area of the drawing drum 44 in FIG. 8). 200. In the drawing area immediately below the inkjet heads 48M, 48K, 48C, and 48Y, an image is formed on the recording medium, and the recording medium on which the image is formed is transferred to a transfer cylinder 52 provided on the rear stage side of the drawing unit 40. It is.

  The drawing drum 44 after the recording medium after drawing has been transferred to the transfer cylinder 52 has suction holes (not shown in FIG. 8) in the ink discharge area 202 provided on the rear side of the position where the recording medium is transferred. Air is ejected from (shown by reference numeral 220 in FIG. 9), and the ink clogged in the suction holes is ejected. In FIG. 8, an area indicated by an outward-facing arrow from the outer peripheral surface of the drawing drum 44 is an ink discharge area 202 where ink is discharged.

  That is, the flow path communicating with the suction hole is changed from a suction flow path (not shown in FIG. 8, indicated by reference numeral 236 in FIG. 11) to a discharge flow path (not shown in FIG. 8, reference numerals 244 and 254 in FIG. 11). The suction hole functions as an air outlet.

  A heater (halogen lamp) 204 for heating the outer peripheral surface of the drawing drum 44 is provided on the rear side of the ink discharge region 202. A detailed arrangement structure of the heater 204 illustrated in FIG. 8 will be described later.

  A non-contact infrared temperature sensor 206 for detecting the surface temperature of the drawing drum 44 is provided on the rear side of the heater 204. The temperature sensor 206 includes a thermopile element that detects an infrared ray amount (heat energy amount) emitted from the outer peripheral surface of the drawing drum 44, converts the heat energy into an electric signal, and outputs the electric signal. Further, the temperature sensor 206 is disposed close to the outer peripheral surface of the drawing drum 44 so that the infrared light receiving surface (detection surface) faces the outer peripheral surface of the drawing drum 44. The clearance between the temperature sensor 206 and the drawing drum 44 is appropriately set depending on the configuration of the detection system of the temperature sensor 206.

  Based on the detection result of the infrared temperature sensor 206, the heater 204 is controlled so that the surface temperature of the drawing drum 44 is maintained in the range of 29 ° C. to 31 ° C.

  The suction holes from which ink mist or the like has been discharged in the ink discharge region 202 can eject clean cleaning air (air) that does not contain ink or dust. By blowing this cleaning air onto the light receiving surface of the temperature sensor 206, paper dust and dust adhering to the light receiving surface are removed. That is, the suction holes provided in the outer peripheral surface of the drawing drum 44 for holding the recording medium also function as means for ejecting cleaning air for cleaning the light receiving surface of the temperature sensor 206.

  FIG. 9 is a diagram showing an arrangement relationship between the drawing drum 44 and the heater 204. As shown in the figure, the heater 204 has a drawing drum along a direction along the axial direction (lateral direction in FIG. 9) of the drawing drum 44 in which a plurality of suction holes 220 are arranged in a predetermined arrangement pattern on the outer peripheral surface. It is disposed so as to face the outer peripheral surface of the drawing drum 44 over a length corresponding to the total length of the axial direction 44. FIG. 9 shows a mode in which a plurality of (three) halogen lamps 204A, 204B, and 204C are arranged along the axial direction of the drawing drum 44 and correspond to the total length in the axial direction of the drawing drum 44. A mode in which one halogen lamp whose length corresponds to the entire length of the drawing drum 44 in the axial direction is also possible.

  FIG. 10 is a diagram showing an arrangement relationship between the drawing drum 44 and the temperature sensor 206. In this figure, parts common to those in FIG. 9 are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 10, suction holes 220 are provided on the outer peripheral surface of the drawing drum 44 in an area outside the area corresponding to the maximum size recording medium. The length in the axial direction of the drawing drum 44 illustrated with reference numeral W _{m in} FIG. 10 is the same as the width of the maximum size recording medium (the length in the direction orthogonal to the transport direction, W _m illustrated in FIG. 2). ).

Further, three temperature sensors 206A, 206B, and 206C are disposed at positions facing the outer peripheral surface of the drawing drum 44, corresponding to the three heaters 204A, 204B, and 204C shown in FIG. Three temperature sensors 206A, 206B, of 206C, a temperature sensor 206A and the temperature sensor 206C is provided at a position corresponding to the outside of the maximum width _{W m} of the recording medium, the temperature sensor 206B has a maximum width _{W m} of the recording medium Is provided at a position corresponding to the substantially central portion. That is, the detection result by the temperature sensor 206A is used for controlling the heater 204A, and the detection result by the temperature sensors 206B and 206C is used for controlling the heaters 204B and 204C, respectively.

  The temperature sensor 206 is a temperature sensor using a thermopile element in which two types of different metals or semiconductors are connected in series. Are fixed to a member having a small heat capacity, and these structures are covered with an infrared absorbing member.

  The temperature sensor 206 includes a lens or a filter that transmits only infrared rays emitted from the drawing drum 44 having a specific wavelength, and only infrared rays having a specific wavelength are absorbed by the infrared absorbing member. An electric signal corresponding to the temperature difference between the cold junction and the hot junction is output from the thermopile element. You may comprise so that the electrical signal corresponding to the absolute temperature corresponding to the other may be output on the basis of the absolute temperature corresponding to any one of a cold junction or a warm junction.

  That is, the temperature sensor 206 includes a temperature detection unit including a thermopile element, a lens or filter, and an infrared absorbing member, and a signal output unit that outputs an electrical signal corresponding to the detected temperature, and the drawing drum 44. The light receiving surface of the temperature detection unit is disposed so as to face the outer peripheral surface.

  The suction hole 220 that mainly blows the cleaning air to the temperature sensor 206A and the temperature sensor 206C is not blocked by the recording medium when holding the recording medium, and easily sucks ink mist. Therefore, before the cleaning air is blown to the temperature sensors 206A and 206C, air is blown from the suction holes to discharge ink mist and the like. When the cleaning air is blown to the temperature sensors 206A and 206C, the temperature sensors 206A and 206C are discharged. Adherence of ink mist or the like to 206C is prevented.

  In addition, by distributing a plurality of temperature sensors 206 along the axial direction of the drawing drum 44, the temperature distribution in the axial direction of the drawing drum 44 can be compensated, and the locality of each temperature sensor can be corrected. is there.

  In this example, a mode in which one temperature sensor 206 is provided for one heater 204 is illustrated, but a mode in which a plurality of temperature sensors 206 are provided for one heater 204 is also possible. Further, the apparatus includes a temperature sensor 206 that is smaller than the heater 204 and a scanning mechanism that scans the temperature sensor 206, and is configured to detect the temperature of the heating region of the plurality of heaters 204 while scanning the temperature sensor 206. Also good.

[Description of switching between suction and discharge]
Next, switching between suction and discharge in the suction hole 220 will be described. The inkjet recording apparatus 10 shown in this example includes a mechanism for switching between suction and discharge in the drawing drum 44, and switching between suction and discharge in the suction hole 220 is performed in accordance with the rotation of the drawing drum 44.

  FIG. 11 is an exploded perspective view showing the structure of the drawing drum 44. A flow path switching member 230 including a switching structure for switching between suction and discharge is attached to one end of the drawing drum 44 in the axial direction. In the figure, the drawing drum 44 and the flow path switching member 230 are shown separately.

  The flow path switching member 230 includes an electromagnetic valve 234 connected to the suction pipe 232 and a suction flow path 236 communicated via the electromagnetic valve 234, and a discharge (not shown) provided outside the drawing drum 44. An electromagnetic valve 242 connected to a discharge pipe 240 connected to the pump, a discharge flow path 244 communicated via the electromagnetic valve 242, and an electromagnetic valve 252 connected to a discharge pipe 250 connected to the discharge pump The discharge passage 254 communicated through the electromagnetic valve 252 has a circular shape substantially the same size as the bottom surface of the drawing drum 44, and the central portion 260 is fixed to the rotation shaft 262 of the drawing drum 44.

  The suction pipe 232 is a flow path that connects a flow path of the drawing drum 44 that communicates with the suction hole 220 illustrated in FIGS. 9 and 10 and a suction pump (not illustrated) installed outside the drawing drum 44. Further, the discharge pipe 240 is a flow path that connects the flow path of the drawing drum 44 and a discharge pump (not shown). The suction pump and the discharge pump are included in the pump 180 illustrated in FIG. A separate discharge pump may be provided for the discharge pipe 240 and the discharge pipe 250, or a common discharge pump may be provided for the discharge pipe 240 and the discharge pipe 250.

  The suction flow path 236 corresponds to the area where the recording medium is sucked and held, the discharge flow path 244 corresponds to the ink discharge area 202 where the ink mist is discharged, and the discharge flow path 254 is the area where the temperature sensor 206 is cleaned. It corresponds to.

  The suction flow path 236, the discharge flow path 244, and the discharge flow path 254 are grooves having a circular arc shape formed on the bottom surface side of the drawing drum 44 of the flow path switching member 230. A seal member (packing) is provided around the suction flow path 236, the discharge flow path 244, and the discharge flow path 254 to ensure airtightness.

  On the surface of the drawing drum 44 to which the flow path switching member 230 is attached, pipes 270, 272, 274, 276 (first pipe group 278) connected to a flow path (not shown) formed inside the main body 44A, and Pipes 280, 282, 284, and 286 (second pipe group 288) are provided. The drawing drum 44 has two recording medium holding areas in which suction holes (shown with reference numeral 220 in FIGS. 9 and 10) for holding the recording medium are disposed.

  In FIG. 11, the suction holes provided in the upper recording medium holding area communicate with the first piping group 278, and the suction holes provided in the lower recording medium holding area communicate with the second piping group 288. A plurality of grippers 80 that sandwich the leading end portion of the recording medium are arranged at equal intervals along the axial direction of the drawing drum 44 at the heads of the two recording medium holding areas.

  Each pipe of the first pipe group 278 and the second pipe group 288 communicates with connection ports 292, 294, 296, 298, 300, 302, 304, 306 provided in the connection member 290. The connection ports 292, 294, 296, and 298 (first connection port group 299) are communicated with the first piping group 278, and the connection ports 300, 302, 304, and 306 (second connection port group 307) are connected to the second piping group 288. Communicated with. The connection ports 292, 294, 296, 298, 300, 302, 304, and 306 are arranged on the circumference corresponding to the arc shapes of the suction flow path 236, the discharge flow path 244, and the discharge flow path 254. The connection ports 292, 294, 296, 298, 300, 302, 304, and 306 are provided with seal members for ensuring airtightness.

  A connecting member 290 that rotates together with the drawing drum 44 is attached to the end surface of the drawing drum 44 on the side where the structural flow path switching member 230 is provided. The connecting member 290 rotates with the drawing drum 44 while moving relative to the drawing drum 44. It slides on the channel switching member 230 that is fixedly arranged. When the first connection port group 299 of the connection member 290 reaches the position of the suction flow path 236 of the flow path switching member 230, the first connection port group 299 is connected to a suction pump (not shown) connected to the suction pipe 232. A suction pressure is generated in the suction hole communicating with the first connection port group 299.

  At this time, in the second connection port group 307 on the lower side, the connection ports 300, 302, and 304 reach the position of the discharge flow path 244, and the connection port 306 reaches the position of the discharge flow path 254 and discharge Air is ejected from a suction hole connected to a discharge pump (not shown) connected to the pipes 240 and 250 and communicating with the second connection port group 307.

  When cleaning air is blown from the discharge flow channel 254, the solenoid valve 242 of the discharge flow channel 244 is closed to concentrate the flow rate on the discharge flow channel 254, and stronger cleaning air is applied from the suction hole communicating with the discharge flow channel 254. It is good to spout.

  For example, according to the rotation of the drawing drum 44, the position of the discharge flow path 244 is reached in the order of the connection ports 306, 304, 302, 300. The electromagnetic valve 242 is kept open until the connection port 306 reaches the position of the discharge flow path 244 and then exits the position of the discharge flow path 244. The electromagnetic valve 242 is closed at the timing when the connection port 306 reaches the position of the discharge flow path 254, and the electromagnetic valve 252 is opened to concentrate the air supplied from the discharge pump to the discharge flow path 254.

  When the connection ports 304, 302, 300 reach the position of the discharge channel 244 before the connection port 306 exits the position of the discharge channel 254, each of the connection ports 304, 302, 300 is positioned at the position of the discharge channel 244. The electromagnetic valve 242 is opened only for a period necessary for discharging ink mist and the like from the timing of reaching.

  In addition, when it is not always necessary to clean the light receiving surface of the temperature sensor (shown with reference numeral 206 in FIG. 8), the light receiving surface of the temperature sensor may be cleaned only at the start of the job. . For example, the normal cleaning mode and the job start cleaning mode can be switched, and when the job start cleaning mode is set, the electromagnetic valve 252 is opened before the job starts to clean the light receiving surface of the temperature sensor. When the job is started, the electromagnetic valve 252 may be closed so that the light receiving surface of the temperature sensor is not cleaned.

  In addition, a switch for switching between the automatic cleaning mode and the manual cleaning mode is prepared in the user interface. In the automatic cleaning mode, the electromagnetic valve 252 is always opened. In the manual cleaning mode, the electromagnetic valve 252 is opened only during cleaning. You may comprise so that the solenoid valve 252 may be closed after completion | finish of cleaning.

  According to the inkjet recording apparatus 10 configured as described above, the surface temperature of the drawing drum 44 is detected by using a discharge function for discharging ink mist or the like clogged in the suction hole 220 for sucking the recording medium. Since the cleaning air is sent to the light receiving surface of the temperature sensor 206, the light receiving surface of the temperature sensor 206 is maintained in a clean state free from paper dust and dust, and the detection accuracy of the temperature sensor 206 is prevented from being lowered. Is done.

  Further, since the cleaning air is automatically sent while the drawing drum 44 is operating, it is not necessary for the user or service person to perform a cleaning operation by stopping the print job. Furthermore, since the function provided in the drawing drum 44 is used, it is not necessary to newly add a dedicated product such as a cleaning compressor or a spray nozzle.

  In this example, the ink jet recording apparatus 10 to which the impression cylinder conveyance method is applied is illustrated, but the conveyance method of the recording medium 14 is not limited to the impression cylinder conveyance method, and the recording medium is sucked and held on the conveyance belt. It is also possible to appropriately select a belt conveyance method for conveying the ink and other conveyance methods.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described. FIG. 12 is a configuration diagram showing a configuration around the drawing unit 40 of the inkjet recording apparatus 400 according to the second embodiment. In addition, the same code | symbol is attached | subjected to the part which is common in 1st Embodiment demonstrated previously, and the description is abbreviate | omitted.

  An inkjet recording apparatus 400 shown in FIG. 12 is provided with a cooling device 402 for cooling the surface of the drawing drum 44 and a duct 404 for sending cooling air from the cooling device 402 to the surface of the drawing drum 44. Further, an air flow path 406 for sending cooling air (cleaning air) from the duct 404 to the light receiving surface of the temperature sensor 206 and an air blowing fan 408 are provided, and the cooling air for cooling the surface of the drawing drum 44 is supplied from the temperature sensor 206. It is also used as a cleaning air for cleaning the light receiving surface. The direction indicated by the white arrow line in FIG. 12 indicates the flow direction of the cleaning air guided from the duct 404 to the light receiving surface of the temperature sensor 206.

  In the configuration shown in FIG. 12, the positions of the temperature sensor 206 and the heater 204 are interchanged with respect to the configuration shown in FIG. 8, but the air flow that sends the cleaning air to the light receiving surface of the temperature sensor 206 while avoiding the heater 204. If the path 406 is configured, the heater 204 and the temperature sensor 206 may be arranged as shown in FIG.

  The duct 404 is disposed so that the outlet of the cooling air is on the rear side of the ink discharge region 202, the air flow path 406 has a predetermined flow rate of the cleaning air sent to the light receiving surface of the temperature sensor 206, and The blower fan 408 is provided so as to have a predetermined flow rate, and the channel length, channel diameter, and channel shape are determined.

  FIG. 13 is a plan view showing a planar shape of the duct 404 (a planar shape viewed from the drawing drum 44 side). In FIG. 13, the drawing drum 44 disposed just above the duct 404 is indicated by a broken line.

  The duct 404 for sending the cooling air from the cooling device 402 has a structure in which an opening is widened in the axial direction of the drawing drum 44 from the vicinity of the drawing drum 44 so that the cooling air hits the entire surface of the drawing drum 44. On the other hand, the outlet opening has a narrowed shape so as to be the same as the outlet area of the cooling device 402 so as not to reduce the flow velocity of the cooling air, and the outlet area of the cooling device 402 and the area of the outlet opening substantially coincide. Yes. Furthermore, a plurality of blower fans 408 are provided over the entire width of the drawing drum 44 in order to assist the wind speed due to the pressure loss in the duct 404.

  According to the second embodiment, since the cleaning air is sent to the light receiving surface of the temperature sensor 206 using the configuration for cooling the surface of the drawing drum 44, a new configuration for cleaning the temperature sensor 206 is provided. The temperature sensor 206 can be cleaned using the existing configuration without any problems.

[Example of application to other device configurations]
In the above embodiment, an inkjet recording apparatus has been described as an example of an image forming apparatus. However, the scope of application of the present invention is not limited to this, and not only an inkjet system but also other systems such as a laser recording system and an electrophotographic system. The present invention can also be applied to an image forming apparatus. For example, a thermal transfer recording apparatus having a recording head with a thermal element as a recording element, an LED electrophotographic printer having a recording head with an LED element as a recording element, and a silver salt photographic printer having an LED line exposure head. The present invention can also be applied to a color image forming apparatus.

  In addition, in the interpretation of the term "image forming apparatus", it is not limited to the use of so-called graphic printing such as photographic printing or poster printing, such as a resist printing apparatus, a wiring drawing apparatus for an electronic circuit board, a fine structure forming apparatus, etc. An industrial use apparatus capable of forming a pattern that can be grasped as an image is also included.

<Appendix>
As can be understood from the description of the embodiment described in detail above, the present specification includes disclosure of various technical ideas including the invention described below.

  (Invention 1): Conveying means for holding a recording medium and conveying it in a predetermined direction, temperature detecting means for detecting the temperature of the conveying means in a non-contact manner, and from the conveying means to the temperature detecting portion of the temperature detecting means An image forming apparatus, comprising: a cleaning unit that applies cleaning air to the temperature detection unit to remove deposits attached to the temperature detection unit.

  Since the cleaning air is applied from the conveying means to the temperature detecting portion of the temperature detecting means, the temperature detecting portion is maintained in a preferable clean state, and preferable temperature control is possible.

  An image forming unit that forms an image on a recording medium conveyed by the conveying unit is provided, and an inkjet method, an electrophotographic method, or the like can be applied to the image forming unit.

  The “recording medium” in the present invention is a continuous sheet, a cut sheet, a seal sheet, a resin sheet such as an OHP sheet, a printed board on which a film, a cloth, a wiring pattern or the like is formed, an intermediate transfer medium, and any other material or shape. , Including various media.

  (Invention 2): In the image forming apparatus according to Invention 1, the conveying unit has a structure in which an adsorption hole for generating an adsorption pressure is provided on a medium holding surface on which a recording medium is held, and the cleaning unit includes: A cleaning air blowing means for blowing a cleaning air from the suction hole is included.

  According to this aspect, it is possible to clean the temperature detection unit using an existing configuration without providing a dedicated injection nozzle or the like for cleaning the temperature detection unit.

  The suction hole provided in the medium holding surface communicates with an internal flow path provided inside the medium holding member that holds the medium, and the internal flow path further generates a cleaning air through a predetermined connecting member. Connected to generating means.

  (Invention 3): In the image forming apparatus according to Invention 1 or 2, the image forming apparatus includes discharge air blowing means for discharging discharge air from the suction holes so as to discharge the liquid sucked into the suction holes, and the cleaning means includes In addition, the exhaust air blowing means is also used.

  In such an aspect, the temperature detection unit can be cleaned using an existing function.

  A flow path switching means for switching whether the suction flow path connected to the suction means communicates with the suction holes or whether the discharge flow path connected to the cleaning air generating means (discharge air ejection means) communicates with the suction holes; When holding the recording medium during drawing, the suction hole and the suction channel are communicated, and when the foreign matter in the suction hole is discharged and when the temperature detection unit is cleaned, the suction hole and the discharge channel are communicated. Thus, the flow path can be switched.

  (Invention 4): In the image forming apparatus according to Invention 3, the temperature detection unit is provided on the downstream side in the recording medium conveyance direction with respect to the processing region in which the exhaust air is ejected by the exhaust air ejecting unit. And

  According to this aspect, since the cleaning air is sent from the suction hole to the temperature detection unit after the foreign matter in the suction hole is removed, a preferable cleaning air not mixed in the temperature detection unit is applied.

  (Invention 5): In the image forming apparatus according to Invention 3 or 4, the cleaning unit ejects cleaning air having a flow velocity faster than the exhaust air ejected from the exhaust air ejecting unit.

  According to this aspect, it is possible to improve the cleaning efficiency by blowing strong cleaning air.

  (Invention 6): In the image forming apparatus according to any one of Inventions 1 to 5, the cleaning unit includes a normal operation mode in which a cleaning air is constantly generated, and a job start operation mode in which a cleaning air is generated at the start of the job. And a switching means for switching between.

( Invention 7): In the image forming apparatus according to any one of Inventions 1 to 6, the temperature detection unit corresponds to an infrared detection unit that detects infrared rays radiated from the transport unit and the detected amount of infrared rays. And a temperature information output unit that outputs temperature information of the conveying means.

  In this aspect, it is preferable that the temperature information output unit includes a thermopile element that outputs electrical energy (electric signal) corresponding to the amount of infrared rays (thermal energy).

  (Invention 8): In the image forming apparatus according to any one of Inventions 1 to 7, the temperature detection unit includes a first temperature detection unit configured to detect a temperature in an area inside the maximum size medium in the transport unit; And a second temperature detecting means for detecting the temperature of the area outside the maximum size medium in the transport means.

( Invention 9): In the image forming apparatus according to any one of Inventions 1 to 8, the transport unit has a drum shape and rotates in a state in which the recording medium is held on the outer peripheral surface, so that the recording medium rotates. It includes an impression cylinder that is conveyed along

  In this aspect, a plurality of recording medium holding areas for holding the recording medium are provided, and when one recording medium holding area is located in the image forming area, the other recording medium holding area is located in the arrangement area of the temperature detecting means. A configuration in which the recording medium is held in one recording medium holding area and image formation is performed and cleaning air is applied from the other recording medium holding area to the temperature detection unit is preferable.

  (Invention 10): In the image forming apparatus according to Invention 9, the pressure drum includes an adsorption hole that generates an adsorption pressure that acts on a recording medium on an outer peripheral surface, a flow path that communicates with the suction hole, and the flow path. And an adsorption pressure generating means for generating an adsorption pressure in the adsorption hole; an ejection means for communicating with the flow path and for blowing air from the adsorption hole; and the adsorption pressure generation means in communication with the flow path. Or switching means for switching the ejection means to communicate, and the flow path and the adsorption pressure generating means are in communication with each other so as to generate an adsorption pressure in the adsorption hole during conveyance of the recording medium. And switching control means for controlling the switching means so that the flow path and the ejection means communicate with each other when cleaning is performed.

  According to this aspect, it is possible to switch suction and discharge of the suction holes without applying a complicated flow path switching structure.

  (Invention 11): The image forming apparatus according to Invention 1, further comprising a cooling unit that applies cooling air to the conveying unit, and the cleaning unit detects the temperature of the cooling air applied from the cooling unit to the conveying unit. It is characterized by including an air flow path leading to the part.

  According to this aspect, the configuration for cooling the existing conveying means can be used for cleaning the temperature detection unit.

  An ink jet recording apparatus as one aspect of an image forming apparatus according to the present invention includes a nozzle (discharge port) for discharging ink droplets for forming dots and a pressure generating element (piezoelectric actuator or heating) for generating discharge pressure. A liquid discharge head (recording head) in which a large number of droplet discharge elements including a foaming heating element) are arranged at high density, and the liquid is based on ink discharge data (dot image data) generated from an input image. An ejection control unit that controls ejection of droplets from the ejection head, and forms an image on the recording medium by the droplets ejected from the nozzles.

  For example, color conversion and halftoning processing are performed based on image data (print data) input via the image input means, and ink ejection data corresponding to the ink color is generated. Based on this ink ejection data, the drive of the pressure generating element corresponding to each nozzle of the liquid ejection head is controlled, and an ink droplet is ejected from the nozzle.

  In order to realize high-resolution image output, a droplet discharge element (ink chamber unit) including a nozzle (discharge port) for discharging an ink liquid, a pressure chamber corresponding to the nozzle, and a pressure generation element ) Is preferably used.

  As a configuration example of such an ink jet recording head, a full line type head having a nozzle row in which a plurality of ejection openings (nozzles) are arranged over a length corresponding to the entire width of the recording medium can be used. In this case, a combination of a plurality of relatively short ejection head modules having a nozzle row less than the length corresponding to the entire width of the recording medium, and connecting them together, the nozzle having a length corresponding to the entire width of the recording medium as a whole There is an aspect that constitutes a column.

  A full-line type head is usually arranged along a direction perpendicular to the relative feeding direction (relative conveyance direction) of the recording medium, but has a certain angle with respect to the direction perpendicular to the conveyance direction. There may be a mode in which the head is arranged along the oblique direction.

  The conveying means for relatively moving the recording medium and the recording head includes an aspect for conveying the recording medium to the stopped (fixed) head, an aspect for moving the head with respect to the stopped recording medium, or a head Any of the modes in which both recording media are moved is included. When forming a color image using an ink jet recording head, a recording head may be arranged for each color of a plurality of inks (recording liquids), or a plurality of colors of ink are ejected from one recording head. It is good also as a possible structure.

  DESCRIPTION OF SYMBOLS 10,400 ... Inkjet recording device, 40 ... Drawing part, 44 ... Pressure drum (drawing drum), 168, 206 ... Temperature sensor, 174 ... Valve control part, 176, 234, 242, 252 ... Control valve (electromagnetic valve), 180 ... Pump, 220 ... Suction hole, 236 ... Suction channel, 244,254 ... Discharge channel, 402 ... Cooling device, 404 ... Duct, 406 ... Blower channel

Claims (9)

Conveying means for holding the recording medium and conveying it in a predetermined direction;
Temperature detecting means for detecting the temperature of the conveying means in a non-contact manner;
A cleaning unit that applies cleaning air to the temperature detection unit of the temperature detection unit from the transport unit, and removes adhering matter attached to the temperature detection unit;
Equipped with a,
The transport means has a structure in which a suction hole for generating suction pressure is provided on a medium holding surface on which a recording medium is held;
The image forming apparatus according to claim 1, wherein the cleaning unit includes a cleaning air ejection unit that ejects a cleaning air from the suction hole . The image forming apparatus according to claim 1 .
A discharge air blowing means for discharging a discharge air from the suction hole so as to discharge the liquid sucked into the suction hole;
The image forming apparatus according to claim 1, wherein the cleaning unit is also used as the discharge air ejection unit. The image forming apparatus according to claim 2 .
The image forming apparatus according to claim 1, wherein the temperature detection unit is provided on a downstream side in a recording medium conveyance direction with respect to a processing region where the discharge air is blown out by the discharge air blowing unit. The image forming apparatus according to claim 2 or 3 ,
The image forming apparatus according to claim 1, wherein the cleaning unit ejects cleaning air having a faster flow rate than the exhaust air ejected from the exhaust air ejecting unit. The image forming apparatus according to claim 1 ,
The image forming apparatus according to claim 1, wherein the cleaning unit includes a switching unit that switches between a normal operation mode in which a cleaning air is constantly generated and a job start operation mode in which a cleaning air is generated at the start of a job. The image forming apparatus according to any one of claims 1 to 5,
The temperature detecting means; an infrared detecting section for detecting infrared rays emitted from the conveying means;
A temperature information output unit for outputting temperature information of the conveying means corresponding to the detected infrared amount;
An image forming apparatus comprising: The image forming apparatus according to any one of claims 1 to 6,
The temperature detection means includes first temperature detection means for detecting the temperature of the inner area of the maximum size medium in the transport means;
Second temperature detection means for detecting the temperature of the area outside the medium of the maximum size in the transport means;
An image forming apparatus comprising: The image forming apparatus according to any one of claims 1 to 7,
The image forming apparatus according to claim 1, wherein the conveying unit includes a pressure drum that has a drum shape, rotates in a state where the recording medium is held on the outer peripheral surface, and conveys the recording medium along the rotation direction. The image forming apparatus according to claim 8 .
The impression cylinder has suction holes that generate suction pressure that acts on the recording medium on the outer peripheral surface;
A flow path communicating with the suction hole;
An adsorption pressure generating means communicating with the flow path and generating an adsorption pressure in the adsorption hole;
Ejecting means communicating with the flow path and ejecting wind from the suction hole;
Switching means for switching whether the adsorption pressure generating means communicates with the flow path or the ejection means communicates;
While the recording medium is being conveyed, the flow path and the adsorption pressure generating means are communicated so as to generate an adsorption pressure in the adsorption hole, and the flow path and the ejection means are communicated when the temperature detection means is being cleaned. Switching control means for controlling the switching means so as to
An image forming apparatus comprising:

Images