JP5035483B2 - Liquid ejector - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus. More specifically, the present invention relates to a liquid ejecting apparatus that attaches liquid ejected from an opening of a nozzle plate attached to a liquid ejecting head to a recording material.

  In the liquid ejecting apparatus, when the liquid is adhered without leaving a margin at the peripheral edge of the recording material, an inevitable misalignment between the recording material and the liquid ejecting head is anticipated, and slightly smaller than the size of the recording material. Liquid is sprayed over a wide area. For this reason, in the vicinity of the both side edges and the front and rear edges of the recording material, the liquid is also ejected to the area where the recording material does not exist. Therefore, an absorbing member is disposed at a position facing the liquid ejecting head at a position farther than the recording material, and the liquid that has been ejected and does not adhere to the recording material is absorbed. Thereby, the surrounding contamination by the liquid which did not adhere to the recording material is prevented.

  By the way, when the liquid adheres to the recording material, the portion may be stretched to cause wrinkles on the recording material. When this wrinkle comes into contact with the absorbing member, the liquid already absorbed by the absorbing member contaminates the recording material. Therefore, in many liquid ejecting apparatuses, a gap of about 2 to 4 mm is provided between the recording material and the absorbing member in consideration of the height of the wrinkles of the recording material. Similarly, in order to prevent contamination due to contact, an interval of about 1 mm is also provided between the nozzle plate and the recording material. Therefore, there is an interval of about 3 to 5 mm between the nozzle plate and the absorbing member.

  On the other hand, for the purpose of improving the resolution of the image formed by the liquid on the recording material, the droplets ejected from the opening of the nozzle plate tend to be further miniaturized. Its size is about several pl. Since such a fine droplet has a very small mass, once it is ejected from the nozzle plate, it rapidly loses kinetic energy due to the viscous resistance of the atmosphere. For example, it has been found that a droplet of less than 8 pl has a velocity of approximately zero when it travels about 3 mm in the atmosphere. The fine droplets that have lost the kinetic energy in this way are almost balanced by the drop motion due to gravitational acceleration and the viscous resistance force of the atmosphere, and it takes a long time to finish dropping. The droplet until it falls will float in the air, which is called aerosol.

  Part of the aerosol generated in this manner floats to the outside of the liquid ejecting apparatus and adheres to the periphery. Most of the aerosol adheres to each part in the liquid ejecting apparatus. When aerosol adheres to the transport path of a recording material such as a platen, the recording material transported next is contaminated due to re-adhesion. In addition, when the aerosol adheres to an electric circuit, a linear scale, a rotary encoder, an optical sensor or the like mounted on the liquid ejecting apparatus, the apparatus itself may malfunction. Further, when the user touches the aerosol, the user's hand is soiled.

  Patent Document 1 discloses a liquid ejecting apparatus having a function of actively collecting aerosol by an electric field. In the liquid ejecting apparatus disclosed herein, an absorbing member is disposed at a position facing the nozzle plate for the purpose of adhering and absorbing droplets that have not adhered to the recording material. Further, a metal member serving as one electrode is disposed adjacent to the absorbing member, and a metal nozzle plate having an opening for ejecting liquid is used as the other electrode.

  When different voltages are applied to these electrodes and nozzle plate, an electric field is formed between them. On the other hand, the droplet ejected from the nozzle plate is charged to the same polarity as the nozzle plate by the so-called lightning rod effect at the moment of ejection from the nozzle plate. Therefore, even minute droplets that can become aerosols continue to fly toward the electrode without being decelerated by the action of the Coulomb force received from the electric field, and are adsorbed by the electrode having a potential opposite to its own charge. . Further, the liquid droplets adsorbed on the electrode are absorbed by the capillarity in the absorbing member disposed adjacent to the electrode.

JP 2004-202867 A

  As described above, it has been found that generation of aerosols floating by an electric field can be suppressed by utilizing the fact that the aerosol is charged. However, in the liquid ejecting apparatus having such a function, since a voltage is always applied, a new technical problem arises.

As one of them, when an electric field is generated over the entire period during which the liquid ejecting apparatus is activated, the power consumption increases. In addition, since a high voltage is applied to members such as electrodes that define an electric field, there is a possibility of electric shock when touched. Furthermore, since a high voltage source has a limited operating time, unnecessary electric field formation leads to a shortened device life.
In addition, since the recording operation is performed in the electric field used for collecting the aerosol, the effect of the electric field may be applied to the recording material, which may cause a conveyance failure of the recording material. In particular, when the recording material is thin and flexible, when the relative permittivity of the recording material is high due to surface treatment, coating layer formation, etc., or the recording material itself is a flexible and easily charged material such as a resin film In this case, the recording material itself is charged by the electric field and is attracted to the structure of the liquid ejecting apparatus. For this reason, the recording material may deviate from the conveyance path, resulting in a conveyance failure such as a so-called paper jam.
Furthermore, as another problem, the aerosol that has been suspended without adhering to the recording material may continue to retain kinetic energy by the electric field, and may adhere to an unintended region of the recording material. Such contamination is very conspicuous on the back side of the recording material to which no liquid adheres. Further, in the case where recording is also performed on the back side of the recording material, the contamination on the back side is not simply deteriorated in appearance. Thus, when the electric field is formed for the purpose of preventing contamination by aerosol, another unexpected contamination may occur.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A conductive nozzle plate having an opening; a liquid ejecting head that ejects liquid from the opening toward the recording material; and a liquid ejecting direction from the liquid ejecting head farther than the recording material, An absorbing member that is disposed opposite to the nozzle plate and absorbs liquid that has been ejected from the liquid ejecting head and has not adhered to the recording material; an electrode that is disposed adjacent to the absorbing member; and A potential difference generating means for applying a voltage to generate a potential difference between the nozzle plate and the electrode to form an electric field and electrically attracting the liquid ejected from the liquid ejecting head toward the electrode; A liquid ejecting apparatus comprising: a liquid collection control unit that controls a voltage application period of the potential difference generating unit.

  According to this application example, by controlling the voltage application of the potential difference generating means by the liquid collection control unit, the liquid collection function becomes effective as necessary, power consumption can be suppressed, and a period during which a high voltage is applied Is also controlled, which contributes to improving the safety of the liquid ejecting apparatus. Further, since the liquid collecting function becomes effective as necessary, contamination with liquid and conveyance failure of the recording material can be minimized.

[Application Example 2]
In the liquid ejecting apparatus, the liquid collection control unit selects a control mode from a control mode including at least one of the first control mode and the second control mode based on information on the recording object. A liquid ejecting apparatus that starts or stops the voltage application according to the selected control mode.
In this application example, the control mode related to the start and stop of voltage application is selected based on the information related to the recording material, so that the above-described effects can be achieved more appropriately according to the recording material.

[Application Example 3]
In the liquid ejecting apparatus, the liquid collection control unit applies the voltage after reaching the position where the liquid is ejected from the opening after the recording material comes into contact with the paper feed roller. Liquid ejecting device to start.
In this application example, since the voltage is applied before the liquid is ejected, the liquid collecting function is surely effective, and contamination by the liquid can be suppressed.

[Application Example 4]
In the liquid ejecting apparatus, the liquid collection control unit starts applying the voltage after the recording material comes into contact with a paper discharge roller.
In this application example, since the recording material is sandwiched by the paper discharge roller and the voltage is applied after the position is stabilized, even if the recording material has a characteristic of being easily charged, the recording material is caused by the electric field. Is attracted to the absorbing member to be contaminated, or it is reduced that the conveyance path is deviated from the conveyance path.

[Application Example 5]
The liquid ejecting apparatus, wherein the liquid collection control unit stops the voltage application after the recording object is out of a position where the liquid is ejected from the opening to the recording object.
Since the voltage application is stopped during the period when the liquid is not ejected, power consumption can be suppressed and the period during which the high voltage is applied is limited, which contributes to the improvement of the safety of the liquid ejecting apparatus. Further, since an effective electric field is formed before the liquid is ejected, the liquid can be collected effectively.

[Application Example 6]
The liquid ejecting apparatus, wherein the liquid collection control unit stops the voltage application when a housing of the liquid ejecting apparatus is opened.
In this application example, the electrodes and the like are prevented from being exposed while the voltage is applied, and the safety of the liquid ejecting apparatus is improved.

[Application Example 7]
The liquid ejecting apparatus, wherein the liquid collection control unit stops the voltage application when it is detected that an object other than the recording object has entered the housing of the liquid ejecting apparatus. .
In this application example, it is possible to prevent a short circuit caused by an intruder or an electric shock that may occur when the intruder is to be removed, and the safety of the liquid ejecting apparatus is improved.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. Therefore, a sub-combination of these feature groups can also be an invention.

FIG. 2 is a perspective view of an overview of a recording / reading multifunction peripheral. The perspective view which extracts and shows the internal mechanism of a recording part. The top view which shows a mode that the internal mechanism was seen from upper direction. The disassembled perspective view which shows the structure of a platen. The schematic diagram explaining operation | movement of an aerosol collection mechanism. The figure which shows typically the structure of the system containing a recording / reading multifunction device. The figure which shows the structure of the control system in a system typically. The flowchart which shows the control procedure of the recording part in a system. The figure which shows the timing of the start and the end of the operation period in each part of a recording part. FIG. 3 is a schematic cross-sectional view of the vicinity of a liquid ejecting head and a platen. FIG. 3 is a schematic cross-sectional view of the vicinity of a liquid ejecting head and a platen. The flowchart which shows the procedure of the additional control by the control part in continuous recording operation | movement.

  Hereinafter, although embodiment of this invention is described, the following embodiment does not limit the invention which concerns on a claim. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a perspective view illustrating an appearance of a recording / reading multifunction device 100 including a recording unit 110 as a liquid ejecting apparatus including an ink jet type liquid ejecting head according to an embodiment of the present invention. The recording / reading complex machine 100 ejects ink, which is liquid, from a liquid ejecting head, and records an image on a recording medium 150 as a recording object.

  In FIG. 1, the recording / reading multifunction machine 100 includes a recording unit 110 and an upper case 122 superimposed thereon. Further, the upper case 122 is a casing, and includes a reading unit 120 therein.

The recording unit 110 includes a lower case 112 and a feeding unit 210. The lower case 112 is a casing, and has a case bottom 111 at the lower part thereof.
The feeding unit 210 includes a paper support 212 and is provided on the rear side of the lower case 112. A front cover 114 is provided on the front surface of the lower case 112.

On the other hand, on the upper surface of the upper case 122, a reading table (not shown) on which a document to be read is placed is arranged, and an upper cover 124 that also serves as a document presser for pressing the document on the reading table is provided.
An operation panel 130 is provided on the front side of the upper cover 124. In addition to the display panel 132, the operation panel 130 is provided with a plurality of operation buttons 134, a pilot lamp 136, and the like. Can be displayed.

  In the recording / reading multifunction peripheral 100, the image on the document placed on the reading table with the upper cover 124 opened is read from the lower surface thereof. Further, the recording medium 150 loaded in the paper support 212 is conveyed forward in the recording unit 110, and an image is recorded in the middle thereof.

FIG. 2 is a perspective view showing the internal mechanism 200 of the recording unit 110 of the recording / reading multifunction peripheral 100 shown in FIG. FIG. 3 is a plan view showing the same internal mechanism 200 as viewed from above.
2 and 3, the internal mechanism 200 is sequentially disposed on the case bottom 111, a frame 202 substantially upright thereon, a feeding unit 210 disposed on the rear side of the frame 202, and a front side of the frame 202. A transport unit 220, a platen 230, and a discharge unit 240.

  The feeding unit 210 includes a paper support 212 that supports the back surface of the recording medium 150 that is vertically loaded, a side support 214 that positions the right side end of the recording medium 150, and a left side end of the recording medium 150. And a slide support 216 that prevents the recording medium 150 from tilting. The slide support 216 can be moved horizontally on the surface of the paper support 212, and even when a recording medium 150 having a different width is loaded, the slide support 216 can be brought into contact with the side end of the recording medium 150. The feeding unit 210 further includes a feeding roller hidden in the frame 202, and when the recording unit 110 performs a recording operation, a plurality of recording media 150 loaded in the paper support 212 are stored one by one in the internal mechanism 200. take in.

  The internal mechanism 200 also includes a horizontal paper support 211 that opens to the front. The paper support 211 supports the recording medium 150 loaded horizontally from the front of the internal mechanism 200 from below. Further, the recording medium 150 loaded in the paper support 211 can also be fed into the transport unit 220 using the feeding unit 210. The paper support 211 includes an extension 213 and can support the recording medium 150 longer than its own depth.

  The transport unit 220 includes a transport driven roller 224 that is disposed on the front side of the frame 202 and serves as a paper feed roller that is rotated in contact with the upper surface of the captured recording medium 150. A conveyance driving roller that is driven to rotate by a conveyance motor (not shown) is disposed immediately below the conveyance driven roller 224. Accordingly, the recording medium 150 taken into the internal mechanism 200 is pressed against the transport driving roller by the transport driven roller 224 and fed onto the platen 230 according to the rotation of the transport driving roller.

  The platen 230 includes a plurality of ribs 234 that protrude upward. The rib 234 has its tip abutted against the lower surface of the fed recording medium 150 to position the recording medium 150 in the height direction. The recording medium 150 that has passed over the platen 230 eventually reaches the discharge unit 240.

  The discharge unit 240 includes a discharge driven roller 244 that is disposed on the front side of the platen 230 and is rotated in contact with the upper surface of the recording medium 150 that has been fed through the platen 230. Immediately below the discharge driven roller 244 as a paper discharge roller, a discharge drive roller that is rotationally driven by a conveyance motor via a rotation transmission mechanism (not shown) is disposed. The recording medium 150 is pressed against the conveyance drive roller by the discharge driven roller 244 and sends the recording medium 150 to the front of the recording unit 110 according to the rotation of the discharge drive roller. A discharge tray 248 is disposed in front of the discharge unit 240, and the discharged recording medium 150 is accumulated on the discharge tray 248.

  Furthermore, the internal mechanism 200 includes a carriage 250 that reciprocates above the platen 230. The carriage 250 is mounted so as to move horizontally in the main scanning direction along a guide member (not shown) provided in the main scanning direction provided on the front side of the frame 202. Further, a timing belt 253 stretched between a pair of pulleys 251 is disposed on the front side of the frame 202. Further, the carriage 250 is connected to the timing belt 253 on the back surface thereof.

  On the other hand, since one of the pulleys 251 is rotationally driven by the carriage motor 255, the carriage 250 moves according to the displacement of the timing belt 253. Therefore, by controlling the operation and rotation direction of the carriage motor 255, the carriage 250 can be moved above an arbitrary area on the platen 230. The carriage 250 includes a liquid ejecting head (not shown) on the lower surface thereof.

  In the recording / reading multifunction device 100 including the internal mechanism 200 having the above-described structure, the recording medium 150 loaded in the front paper support 211 or the rear paper support 212 is fed one by one by the feeding unit 210. It is taken into the transport unit 220. The recording medium 150 taken into the transport unit 220 passes over the platen 230 and reaches the discharge unit 240, and is sent out of the internal mechanism 200 by the discharge unit 240.

  When the recording medium 150 exists on the platen 230, the carriage 250 ejects ink from the liquid ejecting head downward while reciprocating on the platen 230. Therefore, ink can be ejected and adhered to an arbitrary area on the surface of the recording medium 150. Further, while the recording medium 150 is intermittently conveyed one line at a time, the carriage 250 is reciprocated while the conveyance is interrupted, whereby an image can be recorded in a desired area on the entire surface of the recording medium 150.

  A control unit 260 that controls a series of recording operations as described above is mounted on the rear side of the frame 202. The control unit 260 causes the recording unit 110 to perform an appropriate operation based on an instruction input via the information processing apparatus connected to the recording / reading multifunction peripheral 100 or an instruction input from the operation panel 130. To control. The control unit 260 is also an interface that receives image information recorded by the recording unit 110. The image information received by the control unit 260 may include information relating to the recording object such as recording quality such as resolution and number of colors, dimensions, and materials in addition to information representing the image.

FIG. 4 is an exploded perspective view showing a detailed structure of the platen 230 in the internal mechanism 200. In the drawing, a liquid jet head 256, a control unit 260, and a voltage source 270 as a potential difference generating unit controlled by the control unit 260 are also shown in a simplified manner. Here, the liquid ejecting head 256 includes a nozzle plate 252 having an opening 254. Ink is ejected from the opening 254.
In FIG. 4, the platen 230 includes a platen main body 232, an electrode 310 and absorbing members 236 and 238 accommodated in the platen main body 232.

  The platen main body 232 is integrally formed of a resin material, and has a plurality of ribs 234 protruding upward from the upper surface thereof, and a wide accommodating portion 235 formed by including a bottom portion 231 and a side wall portion 233 that is depressed from the upper surface. And a narrow accommodating portion 237 formed on the side of the region where the rib 234 is formed. When the recording medium 150 shown in FIGS. 1 and 2 passes over the platen 230, the upper ends of the ribs 234 come into contact with the lower surface of the recording medium 150, and the recording medium 150 is positioned in the height direction.

  The absorbing members 236 and 238 have dimensions and shapes that fill the accommodating portions 235 and 237. The materials of the absorbing members 236 and 238 are selected with emphasis on the liquid absorption speed on the surfaces thereof. Here, since the amount of ink that can be held by the absorbing members 236 and 238 is limited, a waste liquid absorbing member (not shown) having a larger ink absorption capacity than the absorbing members 236 and 238 is separately disposed below the platen 230. ing.

  Further, the platen 230 includes an electrode 310 disposed under the absorbing member 236 inside the wide accommodating portion 235. The electrode 310 is disposed so as to substantially cover the bottom portion 231 of the housing portion 235. Further, at one end of the electrode 310, a connecting portion 312 that extends over the side wall portion 233 of the housing portion 235 and extends to the outside and a terminal portion 314 that is exposed to the outside of the platen 230 are integrally formed. A voltage can be applied to the electrode 310 by connecting to one end of the voltage source 270 operating under the control of the control unit 260 via the terminal unit 314. The other end of the voltage source 270 is connected to a nozzle plate 252 provided in the liquid jet head 256. Thereby, a potential difference is generated between the nozzle plate 252 and the electrode 310, and an electric field can be formed.

In addition, as a material of said absorption member 236,238, what foamed resin materials, such as polyethylene and a polyurethane, can be illustrated preferably. For the purpose of setting the absorbing member 236 to the same potential as the electrode 310, it is also preferable to form the absorbing member 236 from a conductive material having a surface resistance of 10 ⁸ Ω or less. Examples of such materials include those obtained by mixing a resin such as polyethylene and polyurethane with a conductive material such as metal and carbon and then foaming, and a resin foam material such as polyethylene and polyurethane having a conductive material such as metal and carbon. For example, an attached material or a plated material can be used. Moreover, what impregnated electrolyte solution to resin foam materials, such as polyethylene and a polyurethane, can also be used.

  On the other hand, as the material of the electrode 310, a metal having corrosion resistance to ink, such as gold, stainless steel or nickel wire, plate or foil, or wire, plate or foil plated with these metals, or these It can be formed of a net-like or lattice-like member combining these materials. As another embodiment, a conductive coating layer, a plating layer, a thick film layer, a thin film layer, or the like directly formed on the bottom portion 231 of the accommodating portion 235 of the platen 230 can be used as the electrode 310.

FIG. 5 is a schematic diagram for explaining the structure and operation of the aerosol collecting mechanism 300 including the platen 230, the nozzle plate 252, the control unit 260, and the voltage source 270.
In FIG. 5, the nozzle plate 252 is made of, for example, metal and has conductivity. The nozzle plate 252 is connected to the negative electrode of the voltage source 270. On the other hand, the positive electrode of the voltage source 270 is connected to the electrode 310 accommodated in the platen 230. The absorbing member 236 accommodated in the platen 230 so as to overlap the electrode 310 has conductivity, and the entire absorbing member 236 has the same potential as the electrode 310. Therefore, an electric field E due to the potential difference generated by the voltage source 270 is formed between the lower surface of the nozzle plate 252 and the surface of the absorbing member 236. The same function can be realized even if all the polarities are reversed and connected.

  The nozzle plate 252 is attached to the lower surface of the liquid jet head 256. In the recording operation, the ink 311 is ejected downward through the opening 254. Here, when the recording medium 150 supported by the platen 230 exists immediately below the opening 254, the ejected ink 311 adheres to the upper surface of the recording medium 150 to form an image 319. On the other hand, when the ink 311 is to be attached without providing a margin at the edge of the recording medium 150, the recording medium 150 is located immediately below a part of the openings 254 at the side edge and the front and rear ends of the recording medium 150. May not exist. In such a case, the ink 311 flies without adhering to the recording medium 150 while being ejected from the nozzle plate 252.

  The kinetic energy of the ink droplet 317 ejected from the opening 254 and not attached to the recording medium 150 is rapidly lost due to the viscous resistance of the atmosphere. For this reason, some ink droplets 317 lose their kinetic energy long before they reach the absorbing member 236. Here, since the mass of the ink droplet 317 is very small, when the kinetic energy is lost, the drop motion due to the gravitational acceleration and the viscous resistance force due to the atmosphere are almost balanced, and the subsequent drop speed becomes extremely slow. In this way, aerosol floating below the nozzle plate 252 is generated. In addition, a part of the ink droplet 317 may be broken to produce a satellite ink 315 that is a finer ink droplet, which also becomes an aerosol.

  However, in the aerosol collecting mechanism 300, an electric field E is formed between the surface of the absorbing member 236 and the lower surface of the nozzle plate 252. Therefore, the ink droplet 317 having the charge q obtains kinetic energy by the Coulomb force Fe (qE) received from the electric field E, moves down without being decelerated, and reaches the absorbing member 236.

  The ink 311 pushed out from the opening 254 forms an ink column 313 that hangs down from the nozzle plate 252 at the moment immediately before the ink 311 leaves the nozzle plate 252 and becomes an ink droplet 317. At this time, electric charges are accumulated between the tip A of the ink column 313 and the region B near the ink column 313 on the lower surface of the nozzle plate 252 by a so-called lightning rod effect. Due to the lightning rod effect, the ink droplet 317 is charged with a charge q larger than the charge corresponding to the horizontal cross-sectional area of the ink column 313. The lightning rod effect refers to a phenomenon in which the region B on the surface of the nozzle plate 252 that is surrounded by a cone having an apex angle of 50 ° to 60 ° with the tip A of the ink column 313 as a vertex contributes to charging of the ink droplets 317. As a result, the ink droplet 317 receives a larger Coulomb force and flies through the electric field E to the absorbing member 236.

FIG. 6 is a diagram schematically showing the structure of the system when operating the recording / reading multifunction device 100 including the recording unit 110 including the control unit 260 shown in FIG. is there.
6, in this system 500, the control unit 260 shown in FIG. 5 of the recording / reading multifunction peripheral 100 is connected to an information processing apparatus 510 as a host apparatus. The information processing apparatus 510 includes a keyboard 512 and a mouse 514 that are input means from the user, and a display device 520 that displays an image to the user.

  The information processing apparatus 510 also includes a disk drive 516 that reads / writes information from / to the recording medium 150 and a communication line (not shown) that can exchange information by communicating with the outside. Therefore, the information processing apparatus 510 prepares image information to be recorded in the recording unit 110 via the recording medium inserted in the disk drive 516, the communication line, etc., in addition to the image information created therein. Can do. Further, a program for controlling the recording / reading multifunction peripheral 100 can be acquired from outside and installed.

FIG. 7 is a diagram schematically showing the structure of the control system 600 in the system 500 shown in FIG.
In FIG. 7, the control unit 260 mounted on the recording unit 110 is a recording operation control unit 262 that controls the recording operation in the recording unit 110 and a liquid collection control unit that controls the operation of the voltage source 270 in the aerosol collection mechanism 300. Liquid collection operation control unit 264.

  Therefore, the recording operation in the recording unit 110 is executed in the recording unit 110 under the control of the recording operation control unit 262 in accordance with an instruction received by the control unit 260 from the information processing apparatus 510 serving as the host device. The voltage source 270 controls the start or stop of voltage application by the voltage source 270 in cooperation with the recording operation control unit 262 under the control of the liquid collection operation control unit 264.

FIG. 8 is a flowchart showing a procedure when the control unit 260 controls the operation of the aerosol collection mechanism 300.
7 and 8, the control unit 260 that has started the operation waits for a print instruction from a host device such as the information processing device 510 connected to the outside (step S101).
When a print instruction is received, first, record information to be printed on the recording medium 150 is acquired (step S102). The recording information includes information such as the printing resolution, the size of the recording medium 150, and the medium type related to the recording medium 150, in addition to the image information to be printed.

  Next, it is inspected whether or not the recording medium 150 to be subjected to the recording operation is loaded in the recording unit 110 (step S103). When the recording medium 150 is not loaded (step S103: NO), a message “recording medium replenishment” indicating that the recording medium 150 should be replenished is displayed (step S104) and the replenishment of the recording medium 150 is awaited. On the other hand, when the recording medium 150 is already loaded (step S103: YES), the process proceeds to the next step.

  Note that the information on the medium type may be acquired from the determination unit that determines the medium type of the recording medium 150 loaded in the recording unit 110. The medium type can be determined by measuring the relative dielectric constant, bending rigidity, optical surface gloss, light reflectance, etc. of the recording medium 150. In this case, the determination is performed after step S103 after the recording medium 150 is loaded.

Next, in step S105, a control mode corresponding to the acquired medium type information is selected. In the embodiment, as a control mode, a mode A that is a first control mode, a mode B that is a second control mode, and a mode C that is another control mode are provided. Table 1 shows the relationship between the medium type and the corresponding mode.
Mode A and mode B are modes in which voltage is applied and the period is controlled, and mode C is a mode in which no voltage is applied.

Plain paper is paper that has not been surface-treated or has a coating layer, special paper is paper that has been coated on the paper surface, and glossy paper is paper that has a coating on the surface. The glossy paper or matte paper that has been applied refers to a matte paper that has been coated on the surface of the paper.
Glossy film is made of a synthetic resin film, and the surface is glossy but opaque. The OHP sheet is made of a synthetic resin film, and the surface is glossy and transparent. And synthetic resin.

Here, when the relative permittivity of the recording medium 150 is high, for example, when a film of a synthetic resin is included, the recording medium 150 accumulates a large charge, so that it is attracted to the structure of the recording unit 110 by the action of an electric field. It becomes easy. Further, when the bending rigidity of the recording medium 150 is low, the recording medium 150 bends easily even if the action of the electric field on the recording medium 150 is small.
As described above, in the case where the recording medium 150 is bent greatly during conveyance, it is difficult to guide the leading edge of the recording medium 150 between the discharge driving roller 245 / discharge driven roller 244, and a conveyance failure (jam) is likely to occur. . The control mode selection of the aerosol collection mechanism 300 according to the present embodiment is set in view of the relationship between the type of the recording medium and the conveyance failure due to the electric field as described above.

  Specifically, mode B or mode C is selected for glossy films, OHP sheets, and sticker sheets containing synthetic resin depending on the ease of charge accumulation and bending rigidity. More specifically, it is preferable to select the mode C when the charge is easily accumulated and the bending rigidity is low.

In the case of mode A, the feeding unit 210 shown in FIG. 1 of the recording unit 110 is operated to start capturing the recording medium 150 (step S106).
The mode A will be described below with reference to FIGS. Mode A includes steps S106, S107, S108, S109, S110, S111, and S112.
When loading of the recording medium 150 is started, voltage application by the voltage source 270 is started via the liquid collecting operation control unit 264 (step S107). Here, the reason why the voltage application is started prior to the recording operation in which the aerosol is generated is that it may take time until the high voltage applied for forming the electric field is stabilized. In the above description, the operation in step S107 is described as “start voltage application”. However, if voltage application has already started, it means that voltage application is continued.

Further, following the start of voltage application, when the applied voltage is stabilized and aerosol collection by the action of the electric field becomes effective, ink ejection to the recording medium 150 in the recording unit 110 is started (step S108). .
The recording operation with ink ejection is continued while information on the image to be recorded remains (step S109). On the other hand, when there is no more information on the image to be recorded, the control unit 260 terminates ink ejection via the recording operation control unit 262 (step S110).

  However, even after the ink ejection is finished and no new aerosol is generated, the voltage application is continued until the predetermined period T elapses (step S111). This is because it takes a certain time for the aerosol generated in the vicinity of the nozzle plate 252 shown in FIG. 5 to reach the absorbing member 236 in the recording operation. Thus, when the predetermined period T during which the aerosol can reach the absorbing member 236 has elapsed, the voltage application by the voltage source 270 is also stopped (step S112). In this way, a series of control of the control unit 260 related to the recording operation and the liquid collecting operation control of the recording unit 110 is completed. Here, the predetermined period T may be 0 seconds.

Hereinafter, the control of the start and stop of voltage application in mode A will be described in more detail with reference to FIGS.
FIG. 9 is a diagram showing the start and end timings of the operation period in each unit of the recording unit 110 shown in FIG.
FIG. 10 is a schematic cross-sectional view of the vicinity of the liquid ejecting head 256 and the platen 230. FIG. 10A is a diagram illustrating the timing of voltage application start. FIG. 10B is a diagram illustrating the timing of voltage application stop. A two-dot chain line U indicates the position of the opening 254 at the uppermost stream, and a two-dot chain line L indicates the position of the opening 254 at the most downstream position.
In FIG. 10, the recording medium 150 is sent to the platen 230 by the conveyance driven roller 224 and the conveyance driving roller 225. The fed recording medium 150 is discharged by the discharge driven roller 244 and the discharge drive roller 245.

  In FIG. 9, the recording unit 110 that was initially in a standby state after waiting for a print instruction receives the print instruction (step S101), and starts acquiring record information (corresponding to step S102). Subsequently, when recording information capable of performing a certain amount of recording operation is acquired, a control mode corresponding to the acquired medium type information is selected (corresponding to step S105).

In parallel with the acquisition of the recording information, the recording medium 150 starts to be taken in and conveyed (step S106). Further, voltage application is started prior to ink ejection so that the applied voltage becomes stable when ink ejection to the captured recording medium 150 is started (step S107).
In FIG. 10A, the voltage can be applied after the recording medium 150 starts to be taken in and conveyed, but after contacting the conveyance driven roller 224, the tip of the recording medium 150 is the most upstream nozzle position. This is preferably performed until the position of the two-dot chain line U is reached (step S107). After the leading end of the recording medium 150 reaches the position of the two-dot chain line U, which is the position of the opening 254 at the most upstream, ink ejection is started (step S108).
The position of the two-dot chain line U is a position where the ink droplet 317 is ejected from the opening 254 onto the recording medium 150 and is the most upstream position.

Further, voltage application is continued even after the ejection of ink to the recording medium 150 is completed, and the voltage application is stopped after a predetermined period T (step S111).
In FIG. 10B, the application of the voltage is stopped after the rear end of the recording medium 150 passes through the position of the two-dot chain line L, which is the most downstream nozzle position (step S112).
The position of the alternate long and two short dashes line L is a position where the ink droplet 317 is ejected from the opening 254 to the recording medium 150 and is the most downstream position.

  When the recording medium 150 on which the ink has been ejected and the image is recorded is ejected from the recording unit 110, it is considered that the recording operation has been completed and the predetermined period T has not elapsed. Regardless, the power switch of the recording / reading multifunction peripheral 100 may be cut off. However, it takes time for the aerosol generated from the last ejected ink to reach the absorbing member 236 and be absorbed after the ink ejection is completed. Therefore, even if the power switch is shut off, it is preferable to maintain the voltage application until a predetermined period T elapses.

In FIG. 8, when the mode is other than mode A in step S105, the process proceeds to step S120.
In step S120, it is determined whether or not the liquid collection should be shifted to the execution step, and the determination result is shown in the flag (step S121 or step S122).
The information of the recording medium 150 acquired here is not based on the characteristic value of the recording medium 150 such as relative permittivity or bending rigidity, but directly displays the type of the recording medium 150 provided from the information processing apparatus 510. Information. Accordingly, the recording unit 110 determines whether or not the liquid collection should be shifted to the execution step directly from the acquired type information of the recording medium 150 (step S120), and indicates the determination result as a flag (step in mode B). In step S121 and mode C, step S122).

Mode B will be described in detail below. Mode B includes steps S121, S123, S124, S125, S126, S127, S109, S110, S111, and S112.
FIG. 11 is a schematic cross-sectional view of the vicinity of the liquid ejecting head 256 and the platen 230. FIG. 11A is a diagram illustrating the timing of starting voltage application. FIG. 11B is a diagram illustrating the timing of stopping the voltage application. The contents of the reference numerals in the drawing are the same as those in FIG.

After step S120, the print medium is taken in (step S123), and ink ejection is started (step S124).
The recording unit 110 waits for the arrival of the timing at which voltage application for liquid collection should be started while maintaining the state of the flag (step S125), and refers to the flag when the timing has arrived (step S126). If the flag is ON at the timing when voltage application should be started, voltage application is started (step S127), and liquid collection is executed.

In FIG. 11A, voltage application is performed after the leading edge of the recording medium 150 reaches the position of the discharge driven roller 244. In this case, the recording medium 150 is subjected to bending force due to the influence of the electric field. However, since the leading end of the recording medium 150 is nipped between the discharge driving roller 245 and the discharge driven roller 244, there is a risk of causing a jam. There is no sex.
Thereafter, the recording operation is continued (step S109). As shown in FIG. 11B, after ink ejection is completed (step S110), the voltage application is stopped when the rear end of the recording medium 150 is the most downstream opening position. This is performed after passing through the position of the two-dot chain line L (step S112).

In step S126, if the flag is OFF at the timing to start voltage application, voltage application (step S127) is not performed and the recording operation is continued (step S109). This mode becomes mode C.
In mode C, since no voltage is applied, the operations of step S111 and step S112 are virtually not performed.

Hereinafter, additional control for continuing the recording operation in step S109 will be described.
FIG. 12 is a flowchart showing an additional control procedure for continuing the recording operation in step S109 among the procedures shown in FIG.
As shown in FIG. 12, while the recording operation continues in step S109, the control unit 260 monitors whether or not the upper case 122 of the recording / reading multifunction peripheral 100 shown in FIG. Step S201).

  Here, when the upper case 122 is opened for some reason (step S201: NO), the control unit 260 stops the recording operation and stops the voltage operation when the voltage source 270 is applied (step S201: NO). Step S203). This prevents the recording operation from being performed with the upper case 122 opened and the recording head exposed. Further, exposure of a member to which a voltage is applied by the voltage source 270 can be prevented, and an electric shock or the like can be prevented in advance.

  In addition, the control unit 260 also monitors the presence of intruders inside the recording unit 110 (step S202). When it is detected that there is an intruder in the recording unit 110 (step S202: NO), the control unit 260 stops the recording operation and stops the voltage when the voltage source 270 is applied. (Step S203).

When the upper case 122 is closed and the intruder is removed (step S204: YES, step S205: YES), the recording operation is resumed (step S206).
The recording operation is not resumed unless the case is closed (step S204: NO) and the intruder is not removed (step S205: NO).

According to this embodiment, there are the following effects.
(1) By controlling the voltage application of the voltage source 270 by the liquid collection operation control unit 264, the liquid collection function can be validated as necessary, power consumption can be suppressed, and the period during which a high voltage is applied is also controlled. As a result, the safety of the recording unit 110 can be improved. In addition, since the collection function of the satellite ink 315 and the ink droplet 317 can be enabled as necessary, the recording unit 110 can be obtained in which the contamination by the satellite ink 315 and the ink droplet 317 and the conveyance failure of the recording medium 150 are minimized. Can do.

  (2) Since the control mode related to the start and stop of voltage application is selected based on the information related to the recording medium 150, the above-described effects can be achieved more appropriately according to the recording medium 150.

  (3) Since the voltage application is stopped during the period when the satellite ink 315 and the ink droplet 317 are not ejected, the power consumption can be suppressed and the period during which the high voltage is applied is limited. Can contribute. In addition, since an effective electric field is formed before the satellite ink 315 and the ink droplet 317 are ejected, the satellite ink 315 and the ink droplet 317 can be collected effectively.

  (4) Since the recording medium 150 is sandwiched by the discharge driven roller 244 and the voltage is applied after the position is stabilized, even if the recording medium 150 has a characteristic of being easily charged, the recording medium 150 is caused by the electric field. It is possible to reduce the occurrence of a conveyance failure caused by being attracted to the absorbing member 236 and being contaminated, or coming off the conveyance path.

(5) The electrode 310 and the like can be prevented from being exposed while a voltage is applied, and the safety of the recording unit 110 is improved.
In addition, if there is an intruder in the recording unit 110 that is operating, not only the normal recording operation cannot be performed, but the recording unit 110 may be damaged if the recording operation is continued. In addition, when a voltage is applied from the voltage source 270, the nozzle plate 252 and the electrode 310 may be short-circuited by an intruder. Further, when a user's hand or the like is inserted, an electric shock may occur. Therefore, by stopping the recording operation and voltage application when an intruder is detected, these failures can be prevented in advance.

  (6) A short circuit due to an intruder or an electric shock that may occur when the intruder is to be removed can be prevented, and the safety of the recording unit 110 can be improved.

(7) In the recording unit 110 capable of executing this procedure, a unit for detecting the characteristic value of the recording medium 150 may not be provided on the recording / reading multifunction device 100 side. Therefore, the structure of the recording / reading multifunction peripheral 100 can be simplified.
In addition, when the state of the flag is maintained and voltage application is interrupted or interrupted for some reason, appropriate voltage application can be resumed only by referring to the flag.

(8) Since droplets that are aerosolized and then float after being ejected from the liquid ejecting head can be collected, contamination by aerosol can be minimized.
In addition, even when the power of the liquid ejecting apparatus is turned off immediately after the recording operation, the aerosolized and floating droplets are collected, so that contamination by aerosol can be minimized.

Note that it is sufficient that at least two modes among mode A, mode B, and mode C are included, and the number of modes may be four or more.
Further, step S103 and step S104 are not necessary.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the gist thereof.
For example, in the above embodiment, the case where the relative dielectric constant or the bending rigidity of the recording medium 150 is selected as the characteristic value of the recording medium 150 has been described. However, the voltage source 270 is controlled using another characteristic value as an index. You can also. In addition, the voltage source 270 can be controlled in consideration of many types of characteristic values at the same time.

  In the above embodiment, the control unit 260 controls to start or stop the voltage application, but the applied voltage may be switched in a plurality of stages. That is, for example, the bending stiffness of the recording medium 150 may be classified into three types, and high voltage application, low voltage application, or stop may be selected according to the type. Further, characteristic values such as the relative dielectric constant and bending rigidity of the recording medium 150 may be measured each time, and an appropriate voltage may be applied accordingly.

Further, in the series of operations as described above, during the period when the voltage is applied to the electrode 310, the aerosol collecting mechanism 300 is operated by the display panel 132 or the pilot lamp 136 on the operation panel 130 of the recording / reading multifunction peripheral 100. It is also preferable to display that the voltage is applied to the electrode 310 by operating. Thereby, the user can be alerted to the electrode during voltage application.
In this way, by selecting a period effective for aerosol collection and applying a voltage, it is possible to reduce power consumption related to liquid collection. Moreover, the lifetime of the voltage source 270 can be extended by shortening the operating time. Furthermore, by reducing the period during which the voltage is applied, the chance of occurrence of electric shock or the like can be reduced.

  In addition, as an example of the liquid ejecting apparatus, the ink jet recording apparatus mounted as the recording unit 110 of the recording / reading multifunction machine 100 has been described as an example. However, as the liquid ejecting apparatus, a color material ejecting head is used as the liquid ejecting head. Color filter manufacturing apparatus for liquid crystal display, organic EL display having electrode material (conductive paste) jet head as liquid jet head, electrode forming apparatus such as FED (surface emitting display), bio-organic matter jet head as liquid jet head, and A biochip manufacturing apparatus equipped with a precision pipette can be exemplified. The recording material generally refers to a material to which the liquid ejected from the liquid ejecting head can be attached, and includes a circuit board, a disk-shaped optical recording medium, a preparation and the like in addition to the recording medium.

  Furthermore, although the present invention has been described using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. Further, it is apparent from the description of the scope of claims that the embodiment added with such changes or improvements can be included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 110 ... Recording part as a liquid ejecting apparatus, 150 ... Recording medium as a recording material, 224 ... Conveyance driven roller as a paper feed roller, 236, 238 ... Absorption member, 244 ... Discharge driven roller as a discharge roller, 252 ... Nozzle plate, 254 ... Opening, 256 ... Liquid ejecting head, 264 ... Liquid collection operation control unit as a liquid collection control unit, 270 ... Voltage source as potential difference generating means, 310 ... Electrodes, 311 ... Ink as liquid, 315 ... satellite ink as liquid, 317 ... ink droplet as liquid.

Claims (1)

A liquid ejecting head having a conductive nozzle plate having an opening, and ejecting liquid from the opening toward a recording material;
The liquid ejecting head from the liquid ejecting head is disposed at a position farther from the recording material and opposed to the nozzle plate, and absorbs the liquid that has not adhered to the recording material while being ejected from the liquid ejecting head. An absorbent member;
An electrode disposed adjacent to the absorbent member;
A potential difference is generated by applying a voltage to the electrode to generate a potential difference between the nozzle plate and the electrode to form an electric field, and electrically attracting the liquid ejected from the liquid ejecting head toward the electrode. Means,
And a liquid collection control unit for controlling the presence or absence of the voltage application of said potential difference generating means,
The liquid collection control unit generates a potential difference between the nozzle plate and the electrode when the liquid ejecting head ejects liquid toward a predetermined recording object;
A mode in which a potential difference is not generated between the nozzle plate and the electrode when the liquid ejecting head ejects liquid toward the recording material having a relative dielectric constant higher than that of the predetermined recording material. A liquid ejecting apparatus.

Images