JP6028920B2 - Liquid ejector - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus.

Ink jet printers, which are examples of liquid ejecting apparatuses that form images by ejecting ink as liquid from a liquid ejecting head onto a recording medium such as paper conveyed along a support member, include light emitted from a light emitting element. In some cases, an optical sensor that receives light by a light receiving element detects a paper transport position, the presence of paper, and the width of the paper.
If ink mist generated by the ejection of ink droplets from the liquid ejecting head adheres to such an optical sensor, the detection accuracy is lowered.
Therefore, in Patent Document 1, a rotary scale and an optical sensor for detecting the paper transport position are built in a cover member and a floating ink mist adheres to the cover member. Discloses an ink jet printer that does not adhere to the ink. Such an optical sensor is irradiated from the light emitting unit and received by the light receiving unit inside the cover member.

JP 2007-62229 A

  However, when detecting the presence / absence of a sheet and the width of the sheet by the method of Patent Document 1, the cover member is irradiated and irradiated toward the sheet conveyed outside the cover member incorporating the optical sensor. Must be made of transparent material. Therefore, when ink mist adheres to a cover member incorporating an optical sensor, there is a problem in that the amount of light passing through the cover member decreases, and the accuracy of detecting the presence or absence of paper and the width of the paper decreases.

  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 liquid ejecting head that ejects liquid, a light emitting unit that emits light from the light emitting element through the first transparent member, and a light receiving unit that receives light through the second transparent member by the light receiving element, An optical detection unit that receives reflected light of the light emitted from the light emitting unit by the light receiving unit ; and a charging member that is provided in the optical detection unit and is charged by friction with air. The member and the second transparent member are made of a material in the order of the same polarity as the polarity of the mist generated when the liquid is ejected from the liquid ejecting head in the charging train. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is made of a material in an order of polarity opposite to the polarity of the mist.

According to this application example, the first transparent member and the second transparent member are made of a material that is in the same order as the polarity of the mist in the charging train. Thereby, since repulsive force is generated between the mist charged to the same polarity as the mist and the first transparent member and the second transparent member, it is suppressed that the mist adheres to the first transparent member and the second transparent member. The The charging member is made of a material that is in the order of the polarity opposite to the polarity of the mist in the charging train. As a result, an attractive force is generated between the mist charged to the same polarity as the mist and the charging member, so that there is a high possibility that the mist is attracted to the charging member and the mist adheres to the charging member. Therefore, since floating mist decreases, it can suppress that mist adheres to the 1st transparent member and the 2nd transparent member. Therefore, it can suppress that the detection accuracy by an optical detection part falls.

  Application Example 2 In the liquid ejecting apparatus, the charging member is a cover portion that surrounds the optical detection unit.

  According to this application example, an attractive force is generated between the mist charged to the same polarity as the mist and the cover portion, so that there is a high possibility that the mist is attracted to the cover portion side and attached to the cover portion. .

  Application Example 3 A third transparent member that is opposed to the first transparent member and the second transparent member and is held by the cover portion is provided, and the third transparent member has the same polarity as that of the mist in a charging column. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is made of a material in the order of polarity.

  According to this application example, the third transparent member is made of a material that is in the same order as the polarity of the mist in the charge train. Thereby, since repulsive force is generated between the mist charged with the same polarity as the mist and the third transparent member, it is possible to suppress the mist from adhering to the third transparent member.

  Application Example 4 A liquid ejecting head that ejects liquid, a light emitting unit that emits light from the light emitting element through the first transparent member, and a light receiving unit that receives light through the second transparent member by the light receiving element, An optical detector that receives reflected light of the light emitted from the light emitter by the light receiver; a cover that surrounds the optical detector; the first transparent member; and the second transparent member; A third transparent member held by a cover, wherein the third transparent member is in the same order as the polarity of the mist generated when the liquid is ejected from the liquid ejecting head in the charging column. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is made of a material, and the cover portion is made of a material having a polarity opposite to the polarity of the mist in the charging row.

  According to this application example, the third transparent member is made of a material that is in the same order as the polarity of the mist in the charge train. Thereby, since repulsive force is generated between the mist charged with the same polarity as the mist and the third transparent member, it is possible to suppress the mist from adhering to the third transparent member. Further, the cover portion is made of a material that is in the order of the polarity opposite to the polarity of the mist in the charge train. As a result, an attractive force is generated between the mist charged to the same polarity as the mist and the cover portion, so that the mist is attracted and attached to the cover portion. Therefore, the mist floating in the vicinity of the third transparent member is reduced, and the mist is prevented from adhering to the third transparent member. Thereby, it can suppress that the light quantity emitted from the light emission part and the light quantity of reflected light fall by the 3rd transparent member, and can suppress that the detection accuracy by an optical detection part falls.

  Application Example 5 A potential having a polarity opposite to the polarity of the mist is applied, a first sliding portion sliding with the third transparent member, a potential having the same polarity as the mist is applied, and the cover portion and the sliding portion are slid. The liquid ejecting apparatus comprising: a second sliding portion that moves.

  According to this application example, the first sliding portion slides with the third transparent member, and the second sliding portion slides with the cover portion, thereby removing the mist attached to the third transparent member and the cover portion. To do. Further, the third transparent member is strongly charged with the same polarity as the mist, and the cover is strongly charged with the opposite polarity to the mist. Thereby, since the repulsive force between the mist charged in the same polarity as the mist and the third transparent member is increased, it is possible to suppress the mist from adhering to the third transparent member. In addition, since the attractive force between the mist charged to the same polarity as the mist and the cover portion is increased, the amount attached to the cover portion is increased. As a result, mist floating in the vicinity of the third transparent member is reduced.

  Application Example 6 The liquid ejecting apparatus according to the application example, wherein the cover portion has conductivity and the cover portion is grounded.

  According to this application example, the cover portion has no electric potential and is opposite to the polarity of the mist, so that an attractive force can be always generated between the mist and the cover portion.

FIG. 3 illustrates an internal configuration of a printer. FIG. 3 is a cross-sectional view of a main part of the recording head. Sectional drawing explaining the structure of a piezoelectric vibrator. FIG. 3 is a block diagram illustrating an electrical configuration of a printer. The wave form diagram explaining the structure of an ejection drive pulse. (A) is the elements on larger scale of a linear scale, (b), (c) is a figure explaining the structure of a rotary encoder. (A) is a schematic diagram for explaining how positively charged ink is ejected from a recording head, and (b) and (c) are diagrams for explaining how positive charging is further enhanced in a mist. (A) is a figure which shows a paper edge part detection part and a cover part, (b) is the figure which expanded the part of a paper edge part detection part and a cover part. The perspective view of a cover part. (A) is a figure which shows the paper edge part detection part in Embodiment 2, a cover part, and a transparent member, (b) is a figure which shows the paper edge part detection part, cover part, and transparent member in Embodiment 3. (A) is a perspective view of a cover part and a transparent member in Embodiment 4, (b), (c) is a perspective view of a sliding part. FIG. 6 is a schematic diagram illustrating a paper edge detection unit, a cover unit, a transparent member, and a sliding unit in a fourth embodiment. FIG. 10 is a schematic diagram illustrating a sheet end detection unit, a cover unit, a transparent member, and a moving unit in Embodiment 5. FIG. 10 is a diagram illustrating that a charging member is provided in the vicinity of a paper edge detection unit in the sixth embodiment. (A) is a cross-sectional enlarged view of the charging member, (b) is an external view of the charging member.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
(Embodiment 1)
1A and 1B are diagrams illustrating an internal configuration of an ink jet printer 1 (hereinafter referred to as a printer) as a liquid ejecting apparatus, where FIG. 1A is a perspective view and FIG. 1B is a side view. The printer 1 has a recording head 2 that is a kind of liquid ejecting head and a carriage 4 to which an ink cartridge 3 that is a kind of liquid supply source is detachably attached, and a vertical direction of the recording head 2 during a recording operation. A platen 5 disposed below Z, a carriage moving mechanism 7 for reciprocally moving the carriage 4 in the paper width direction of the recording paper 6 (a kind of recording medium and landing target), that is, the main scanning direction X, and the recording paper 6 are provided. A paper feed unit 13 to be set, a transport unit 8 that transports the recording paper 6 in the sub-scanning direction Y orthogonal to the main scanning direction X, a paper discharge unit 14 that discharges the recording paper 6 that has been printed, and a transport unit 8 and a drive motor 15 that drives the paper discharge unit 14, and a transmission unit 16 that transmits the rotational driving force of the drive motor 15 from the transport unit 8 to the paper discharge unit 14.

  The carriage 4 is attached while being supported by a guide rod 9 installed in the main scanning direction X, and is moved along the guide rod 9 in the main scanning direction X by the operation of the carriage moving mechanism 7. It is configured.

  A home position serving as a base point for scanning of the carriage is set in an end area outside the recording area within the movement range of the carriage 4. In the home position in the present embodiment, a capping member 11 for sealing the nozzle forming surface (nozzle plate 50: see FIG. 2) of the recording head 2 and a wiper member 12 for wiping the nozzle forming surface are arranged. Yes. The printer 1 is bi-directional between when the carriage 4 moves from the home position toward the opposite end and when the carriage 4 returns from the opposite end to the home position. So-called bidirectional recording in which characters, images, etc. are recorded on the recording paper 6 is possible.

  The platen 5 is a plate-like member that is long in the main scanning direction X, and a plurality of support protrusions 5a protrude from the surface of the platen 5 at predetermined intervals along the longitudinal direction. Each support protrusion 5a protrudes upward in the vertical direction Z. The upper surface of each support protrusion 5a serves as an abutting surface that supports the recording paper 6, and partially supports the rear surface of the recording paper 6 (the surface opposite to the recording surface on which ink is landed). In addition, an ink absorbing material 5b is disposed on the surface of the platen 5 at a portion that is separated from each support protrusion 5a. The ink absorbing material 5b is made of a porous member having a liquid absorbing property made of, for example, felt or sponge.

  The transport unit 8 includes a transport drive roller 21, a transport driven roller 22, a shaft 23, a rotor 24, and a transport roller drive gear 25. The shaft 23 is rotatably supported on the upper frame 27 of the casing of the printer 1. The transport roller drive gear 25, the upper frame 27, the rotor 24, and the transport drive roller 21 are arranged so as to overlap in this order in the axial direction of the shaft 23 from the front side in FIG. The conveyance drive roller 21, the rotor 24, and the conveyance roller drive gear 25 are connected to a shaft 23 as a rotation axis.

  The rotor 24 is rotated by the driving force of the driving motor 15. Along with this, the transport drive roller 21 and the transport roller drive gear 25 also rotate integrally. The transport roller drive gear 25 meshes with the first transmission gear 37 of the transmission unit 16. Accordingly, when the transport roller drive gear 25 rotates, the driving force of the drive motor 15 is transmitted to the first transmission gear 37 of the transmission unit 16. The transport driven roller 22 is rotatably supported by the housing and is pressed toward the platen 5 by the pressing member 29.

  When the recording paper 6 is fed from the paper supply unit 13, the pressing member 29 presses the conveyance driven roller 22 toward the platen 5, whereby the recording paper 6 is sandwiched between the conveyance driven roller 22 and the platen 5. . When the transport driving roller 21 rotates in this state, the recording paper 6 is transported downstream in the sub-scanning direction Y, and the transport driven roller 22 rotates as the recording paper 6 moves.

  The paper discharge unit 14 includes a paper discharge drive roller 31, a paper discharge driven roller 32, a shaft 33, and a paper discharge unit drive gear 34, on the downstream side (paper discharge side) of the platen 5 in the conveyance path of the recording paper 6. Has been placed. The paper discharge drive roller 31 and the paper discharge unit drive gear 34 are each connected to a shaft 33 as a rotation shaft. The shaft 33 is rotatably supported by the upper frame 27. The paper discharge driven roller 32 is rotatably supported with respect to the upper frame 27, and rotates with the rotation of the paper discharge driving roller 31.

  The paper discharge unit drive gear 34 meshes with the second transmission gear 38 of the transmission unit 16. Accordingly, the driving force by the drive motor 15 is transmitted to the paper discharge unit drive gear 34 via the second transmission gear 38 of the transmission unit 16. When the paper discharge unit drive gear 34 rotates about the shaft 33, the paper discharge drive roller 31 also rotates integrally. When the recording paper 6 is fed from the platen 5 side, the recording paper 6 is sandwiched between the paper discharge driving roller 31 and the paper discharge driven roller 32. When the paper discharge driving roller 31 rotates in this state, the recording paper 6 is conveyed to the paper discharge side, and the paper discharge driven roller 32 rotates as the recording paper 6 moves.

  The transmission unit 16 includes a shaft 36, a first transmission gear 37, and a second transmission gear 38. The first transmission gear 37 and the second transmission gear 38 are arranged in this order from the front in FIG. 1B and are connected to a shaft 36 as a rotation axis. The shaft 36 is rotatably supported by the upper frame 27 of the housing.

  FIG. 2 is a cross-sectional view of a main part for explaining the configuration of the recording head 2. The recording head 2 includes a case 41, a vibrator unit 42 accommodated in the case 41, a flow path unit 43 joined to the bottom surface (tip surface) of the case 41, a cover member 45, and the like. . The case 41 is made of, for example, an epoxy resin, and a housing empty portion 44 for housing the vibrator unit 42 is formed therein. The vibrator unit 42 includes a piezoelectric vibrator 46 that functions as a kind of pressure generating means, a fixing plate 47 to which the piezoelectric vibrator 46 is joined, and a flexible cable 48 that supplies a drive signal to the piezoelectric vibrator 46. ing.

  FIG. 3 is a cross-sectional view in the element longitudinal direction for explaining the configuration of the vibrator unit 42. As shown in the figure, the piezoelectric vibrator 46 is a laminated piezoelectric vibrator formed by alternately laminating a piezoelectric body 67 with a common internal electrode 65 and individual internal electrodes 66. Here, the common internal electrode 65 is an electrode common to all the piezoelectric vibrators 46 and is set to the ground potential. The individual internal electrode 66 is an electrode whose potential varies according to the ejection drive pulse DP (see FIG. 5) of the applied drive signal. In the present embodiment, the free end portion 46a is a portion of the piezoelectric vibrator 46 from the tip of the vibrator to about half or about two-thirds of the vibrator longitudinal direction (direction perpendicular to the stacking direction). Yes. The remaining part of the piezoelectric vibrator 46, that is, the part from the base end of the free end 46a to the vibrator base end is a base end (fixed end) 46b.

  An active region (overlap portion) A in which the common internal electrode 65 and the individual internal electrode 66 overlap is formed in the free end portion 46a. When a potential difference is applied to these internal electrodes 65 and 66, the piezoelectric body 67 in the active region A is activated and deformed, and the free end 46a is displaced in the longitudinal direction of the vibrator to expand and contract. The base end of the common internal electrode 65 is electrically connected to the common external electrode 68 at the base end face portion of the piezoelectric vibrator 46. On the other hand, the tip of the individual internal electrode 66 is electrically connected to the individual external electrode 69 at the tip surface portion of the piezoelectric vibrator 46. Note that the distal end of the common internal electrode 65 is located slightly in front of the distal end surface portion of the piezoelectric vibrator 46 (base end side), and the proximal end of the individual internal electrode 66 is the boundary between the free end portion 46a and the proximal end portion 46b. Is located.

  The individual external electrode 69 (drive electrode) is a series of electrodes formed on the tip surface portion of the piezoelectric vibrator 46 and a wiring connection surface (upper face in FIG. 3) that is one side surface of the piezoelectric vibrator 46 in the stacking direction. The wiring pattern of the flexible cable 48 as a wiring member and each individual internal electrode 66 are electrically connected. And the part by the side of the wiring connection surface of this separate external electrode 69 is continuously formed from the base end part 46b toward the front end side. The common external electrode 68 is formed on the base end surface portion of the piezoelectric vibrator 46, the above-described wiring connection surface, and a fixed plate mounting surface (lower surface in FIG. 3) which is the other side surface of the piezoelectric vibrator 46 in the stacking direction. These are electrodes formed in series, and conduct between the wiring pattern of the flexible cable 48 and each common internal electrode 65. The portion on the wiring connection surface side of the common external electrode 68 is continuously formed from a little before the end portion of the individual external electrode 69 toward the base end surface portion side, and the portion on the fixing plate mounting surface side is It is continuously formed from a position slightly ahead of the distal end surface portion of the vibrator toward the proximal end side.

  The base end portion 46b is a non-operation portion that does not expand and contract even when the piezoelectric body 67 in the active region A is operated. A flexible cable 48 is disposed on the wiring connection surface side of the base end portion 46b, and the individual external electrode 69 and the common external electrode 68 and the flexible cable 48 are electrically connected on the base end portion 46b. Then, a drive signal is applied to each individual external electrode 69 through the flexible cable 48.

  The flow path unit 43 shown in FIG. 2 is configured such that the nozzle plate 50 is bonded to one surface of the flow path forming substrate 49 and the vibration plate 51 is bonded to the other surface of the flow path forming substrate 49. The flow path unit 43 is provided with a reservoir 52 (common liquid chamber), an ink supply port 53, a pressure chamber 54, a nozzle communication port 55, and a nozzle 56. A series of ink flow paths from the ink supply port 53 to the nozzle 56 through the pressure chamber 54 and the nozzle communication port 55 are formed corresponding to each nozzle 56.

  The nozzle plate 50 is a thin plate made of metal such as stainless steel in which a plurality of nozzles 56 are formed in rows at a pitch (for example, 180 dpi) corresponding to the dot formation density. The nozzle plate 50 is provided with a plurality of nozzle rows (nozzle groups) by arranging nozzles 56, and one nozzle row is composed of, for example, 180 nozzles 56.

  The diaphragm 51 has a double structure in which an elastic film 58 is laminated on the surface of the support plate 57. In the present embodiment, the vibration plate 51 is manufactured using a composite plate material in which a stainless steel plate, which is a kind of metal plate, is used as the support plate 57 and a resin film is laminated on the surface of the support plate 57 as an elastic film 58. The diaphragm 51 is provided with a diaphragm portion 59 that changes the volume of the pressure chamber 54. The diaphragm 51 is provided with a compliance portion 60 that seals a part of the reservoir 52.

  The diaphragm portion 59 is produced by partially removing the support plate 57 by etching or the like. That is, the diaphragm portion 59 includes an island portion 61 to which the tip end surface of the free end portion 46 a of the piezoelectric vibrator 46 is joined, and a thin elastic portion 62 surrounding the island portion 61. The compliance part 60 is produced by removing the support plate 57 in the region facing the opening surface of the reservoir 52 by etching processing or the like in the same way as the diaphragm part 59, and the pressure fluctuation of the liquid stored in the reservoir 52 is reduced. Functions as a damper to absorb.

  Since the tip surface of the piezoelectric vibrator 46 is joined to the island portion 61, the volume of the pressure chamber 54 can be changed by extending or contracting the free end portion 46a of the piezoelectric vibrator 46. As the volume changes, pressure fluctuations occur in the ink in the pressure chamber 54. The recording head 2 uses this pressure fluctuation to eject ink from the nozzles 56.

  The cover member 45 is a member that protects the side surface of the flow path unit 43 and the side surface of the head case 41, and is made of a conductive plate material such as stainless steel. A part of the cover member 45 in this embodiment is in contact with the peripheral portion of the nozzle forming surface in a state where the nozzle 56 of the nozzle plate 50 is exposed, and is electrically connected to the nozzle plate 50. . The cover member 45 is grounded, and is brought into contact with the nozzle plate 50 so as to be conductive. For example, static electricity generated from the recording paper 6 or the like is transmitted through the nozzle plate 50, or damage to the driving IC or the like. It is designed to prevent charging.

  FIG. 4 is a block diagram illustrating the electrical configuration of the printer 1. The external device 71 is an electronic device that handles images, such as a computer or a digital camera. The external device 71 is communicably connected to the printer 1 and transmits print data corresponding to the image or the like to the printer 1 in order to cause the printer 1 to print an image or text on a recording medium such as the recording paper 6. .

  The printer 1 in this embodiment includes a drive motor 15, a conveyance unit 8, a transmission unit 16, a paper discharge unit 14, a carriage movement mechanism 7, a linear encoder 10, a rotary encoder 26, a paper end detection unit 90, a head control unit 74, The recording head 2 and the printer controller 72 are included.

  The printer controller 72 is a control unit for controlling each part of the printer. The printer controller 72 includes an interface (I / F) unit 75, a CPU 76, a storage unit 77, and a drive signal generation unit 78. The interface unit 75 transmits and receives printer status data, such as sending print data and a print command from the external device 71 to the printer 1, and receiving the status information of the printer 1. The CPU 76 is an arithmetic processing unit for controlling the entire printer. The storage unit 77 is an element that stores a program for the CPU 76 and data used for various controls, and includes a ROM, a RAM, and an NVRAM (nonvolatile storage element). The CPU 76 controls each unit according to a program stored in the storage unit 77.

  The CPU 76 functions as a timing pulse generator that generates a timing pulse PTS from the linear encoder pulse output from the linear encoder 10. The CPU 76 controls the transfer of print data, the generation of the drive signal COM by the drive signal generation unit 78, and the like in synchronization with the timing pulse PTS. Further, the CPU 76 generates a timing signal such as a latch signal LAT based on the timing pulse PTS and outputs the timing signal to the head controller 74 of the recording head 2. The head controller 74 controls the application of the ejection drive pulse DP (see FIG. 5) of the drive signal COM to the piezoelectric vibrator 46 of the recording head 2 based on the head control signal (print data and timing signal) from the printer controller 72. I do.

  The drive signal generator 78 generates an analog voltage signal based on waveform data relating to the waveform of the drive signal. The drive signal generator 78 amplifies the voltage signal to generate a drive signal COM. This drive signal COM is applied to the piezoelectric vibrator 46 which is the pressure generating means of the recording head 2 in FIG. 2 during the printing process (recording process or jetting process) on the recording medium, and within a unit period which is a repetitive cycle. For example, a series of signals including at least one injection driving pulse DP shown in FIG. Here, the ejection drive pulse DP is for causing the piezoelectric vibrator 46 to perform a predetermined operation in order to eject ink droplets from the nozzles 56 of the recording head 2.

  FIG. 5 is a waveform diagram showing an example of the configuration of the ejection drive pulse DP included in the drive signal COM. In FIG. 5, the vertical axis represents potential and the horizontal axis represents time. In addition, the ejection drive pulse DP changes the potential from the reference potential (intermediate potential) Vb to the maximum potential (maximum voltage) Vmax and expands the pressure chamber 54 in FIG. 2 and the maximum potential Vmax. An expansion maintaining element p2 that maintains for a certain time, a contraction element p3 that rapidly contracts the pressure chamber 54 by changing the potential from the maximum potential Vmax to a minimum potential (minimum voltage) Vmin that is lower than the reference potential Vb, and a minimum. It includes a contraction maintenance (vibration hold) element p4 that maintains the potential Vmin for a fixed time, and a return element p5 that returns the potential from the minimum potential Vmin to the reference potential Vb. The ejection drive pulse DP in the present embodiment has a positive voltage waveform as a whole because the minimum potential (minimum voltage) Vmin is 0 or more, but for example, in relation to the bias voltage applied to the common external electrode 68, The structure which shows a negative value partially may be sufficient. In this case, the voltage of the ejection drive pulse DP is assumed to be positive on average.

  When the ejection drive pulse DP is applied to the piezoelectric vibrator 46, it operates as follows. First, the piezoelectric vibrator 46 contracts by the expansion element p1, and the pressure chamber 54 is expanded from the reference volume corresponding to the reference potential Vb to the maximum volume corresponding to the maximum potential Vmax. Thereby, the meniscus exposed to the nozzle 56 is drawn into the pressure chamber side. The expansion state of the pressure chamber 54 is maintained constant throughout the application period of the expansion maintaining element p2. When the contraction element p3 is applied to the piezoelectric vibrator 46 subsequent to the expansion maintaining element p2, the piezoelectric vibrator 46 expands, whereby the pressure chamber 54 has a minimum volume corresponding to the minimum potential Vmin from the maximum volume. Shrinks rapidly until The ink in the pressure chamber 54 is pressurized by the rapid contraction of the pressure chamber 54, and thereby, several pl to several tens pl of ink is ejected from the nozzle 56. The contraction state of the pressure chamber 54 is maintained for a short time over the application period of the contraction maintaining element p4, and then the return element p5 is applied to the piezoelectric vibrator 46 so that the pressure chamber 54 has a volume corresponding to the minimum potential Vmin. To the reference volume corresponding to the reference potential Vb.

  The position in the main scanning direction X of the carriage 4 in FIG. 1A is detected by the linear encoder 10 in FIG. 4, and the detection signal, that is, the linear encoder pulse is transmitted to the printer controller 72. The linear encoder 10 outputs a linear encoder pulse corresponding to the scanning position of the recording head 2 as position information in the main scanning direction X. That is, the linear encoder 10 functions as a detection device that detects the amount of movement of the carriage 4 and the recording head 2 mounted thereon. The linear encoder 10 includes a linear scale 17 stretched along the main scanning direction X on the inner wall of the back surface of the upper frame 27, and a linear sensor unit 18 attached to the back surface of the carriage 4. The detection method of the linear encoder 10 includes an optical method and a magnetic method, and the optical method is adopted in this embodiment.

  FIG. 6A is a partially enlarged view of the linear scale 17 of FIG. The linear scale 17 is a belt-like member that is long in the moving direction of the recording head 2, that is, in the main scanning direction X. In this embodiment, it consists of the scale center part 17a located in the center of the vertical direction Z, and the scale edge part 17b provided above and below this scale center part 17a.

  The scale central portion 17a is provided with a plurality of light shielding portions 80 that shield light at predetermined intervals along the main scanning direction X. The light shielding portion 80 is a portion printed in a long streak shape (filled with paint or the like) in the vertical direction Z of the scale central portion 17a. By providing a plurality of the light shielding portions 80 at regular intervals, a light transmitting portion 81 capable of transmitting light is provided between the adjacent light shielding portions 80. That is, in the scale center portion 17a, the light transmitting portions 81 and the light shielding portions 80 are alternately provided in a stripe shape along the main scanning direction X to form a detection pattern.

  In addition, when the scale center part 17a consists of an opaque material, the structure which makes a detection pattern by forming a slit-shaped through-hole as a translucent part is also employable, for example. The scale edge portion 17b is a portion not involved in position detection of the carriage 4 (recording head 2).

  The linear sensor unit 18 in FIG. 1B includes a light emitting unit 19 having a light emitting element that emits light and a light receiving unit 20 having a light receiving element that receives light. The light emitting unit 19 and the light receiving unit 20 are disposed so as to face each other with the scale central portion 17 a of the linear scale 17 interposed therebetween, and the optical axis of the light emitting unit 19 is directed to the light receiving unit 20.

  The light emitted (emitted) from the light emitting unit 19 is transmitted through the light transmitting unit 81 of the linear scale 17 and received by the light receiving unit 20, while being shielded by the light shielding unit 80 and not received by the light receiving unit 20. Then, the linear sensor unit 18 sends the linear encoder pulse to the position information of the carriage 4 in the main scanning direction X according to the difference between the light receiving state at the light transmitting part 81 and the light receiving state at the light shielding part 80 of the scale center part 17a. As output.

  6B and 6C are diagrams for explaining the configuration of the rotary encoder 26 in FIG. 4, FIG. 6B is a side view of the rotary encoder 26, and FIG. 6C is a diagram in FIG. It is a BB sectional view taken on the line in FIG. The rotary encoder 26 includes a rotary scale 39 provided on the outer peripheral edge of the rotor 24, a rotor central portion 24 a on the center side (shaft 23 side) of the rotary scale 39, and a rotary sensor portion 40.

  As shown in FIG. 6C, the rotary sensor unit 40 includes a light emitting unit 86 having a light emitting element that emits light, a light receiving unit 87 having a light receiving element that receives light, the light emitting unit 86, and the like. And a bracket 88 for holding the light receiving portion 87. The light emitting unit 86 and the light receiving unit 87 are fixed to the bracket 88 in a state of facing each other with the rotary scale 39 interposed therebetween. The bracket 88 is fixed to the upper frame 27 of the casing of the printer 1 in FIG.

  The optical axis of the light emitting unit 86 is directed to the light receiving unit 87. Light emitted (emitted) from the light emitting unit 86 is transmitted through the slit unit 83 of the rotary scale 39 and received by the light receiving unit 87, but is blocked by the light shielding unit 84 and is not received by the light receiving unit 87. Then, the rotary sensor unit 40 outputs a rotary encoder pulse as conveyance amount information of the recording paper 6 in the sub-scanning direction Y according to the difference between the light receiving state at the slit unit 83 and the light receiving state at the light shielding unit 84. It has become. Accordingly, the printer controller 72 can control the recording operation on the recording paper 6 by the recording head 2 while recognizing the conveyance amount of the recording paper 6 based on the rotary encoder pulse from the rotary sensor unit 40.

  The printer controller 72 in FIG. 4 detects the edge of the recording paper 6 from the change in the amount of light received by the paper edge detection unit 90, and the main scanning direction of the recording paper 6 based on the amount of movement of the carriage 4 by the linear encoder 10. The position of the end in X can be detected.

  FIG. 7A is a schematic diagram for explaining a state in which positively charged ink is ejected from the recording head 2. The common external electrode 68 of the vibrator unit 42 is grounded, and a positive voltage is applied to the individual external electrode 69. As a result, pressure fluctuation occurs in the ink in the pressure chamber 54 by the diaphragm 51 joined to the lower end portion of the vibrator unit 42 via the island portion 61, and the ink is ejected from the nozzle 56 formed in the nozzle plate 50. Is done.

  When a positive voltage is applied to the individual external electrode 69, the piezoelectric vibrator 46 and the pressure chamber 54 are insulated from each other, so that electrostatic induction is present in the vicinity of the island portion 61 in the ink in the pressure chamber 54. This induces a negative charge. A positive charge is induced in the ink in the vicinity of the nozzle 56 on the side opposite to the piezoelectric vibrator 46 in the nozzle communication port 55.

  Therefore, positively charged ink is ejected from the nozzle 56. When the nozzle plate 50 is grounded, the positive charge of the ink moves to the nozzle plate 50 side, but the ink is ejected from the nozzle 56 with the positive charge remaining. As a result, the ink ejected from the nozzle 56 is positively charged.

  The ink ejected from the nozzle 56 is separated into a main droplet 200, a so-called satellite droplet 201 smaller than the main droplet, and a mist 202 smaller than the satellite droplet 201. The main droplet 200, the satellite droplet 201, and the mist 202 fly in a positively charged state.

  FIGS. 7B and 7C are diagrams for explaining how the positive charge is further increased in the mist 202. FIG. The mist 202 in FIG. 7B is electrically configured in a double layer. The core portion 202a of the mist 202 is charged to positive polarity, the portion 202b on the surface side of the mist 202 is charged to negative polarity, and the air in contact with the mist 202 is charged to positive polarity.

  Since the moisture on the surface side of the mist 202 evaporates with a negative charge on the surface, a large amount of positive charge remains in the mist 202 of FIG. 7C, and the mist 202 is charged positively (Leonard). effect).

  Thus, after the ink is ejected from the recording head 2, the positively charged mist floats in the air due to the Leonard effect generated by the evaporation of the surface side of the mist. If the mist drifts in the air for a long time, the amount of evaporation increases, so the amount of mist charge increases.

  FIG. 8A is a diagram seen from the sub-scanning direction Y direction, and is a diagram showing a paper edge detection unit 90 that is an example of an optical detection unit, and a cover 93 that surrounds the paper edge detection unit 90. is there. The paper edge detection unit 90 is provided at the lower end in the vertical direction Z of the carriage 4 on the upstream side of the carriage 4 in the sub-scanning direction Y.

  FIG. 9A is a perspective view of the cover portion 93 provided at the lower end portion of the carriage 4 as viewed from the support protrusion 5a side. The outer shape of the cover part 93 is a cubic shape. A rectangular opening 94 is provided below the cover 93. FIG. 8A is a cross-sectional view taken along a cross-sectional position AA ′ indicated by a broken line in FIG.

  The paper edge detection unit 90 includes a light emitting unit 91 and a light receiving unit 92. As indicated by the broken line, the light emitted from the light emitting portion 91 and passing through the opening 94 is reflected by the recording paper 6 supported by the support protrusion 5a and passes through the opening 94 again and is received by the light receiving portion 92. .

  FIG. 8B is an enlarged view of the paper edge detection unit 90 and the cover unit 93 shown in FIG. The light emitting unit 91 includes a light emitting unit lens 91b as a first transparent member formed from a member having translucency, and a holding unit 91a having a light emitting element 91c such as a light emitting diode in the cavity. The light emitting part lens 91b condenses the light emitted from the light emitting element 91c on the platen 5 side and seals the cavity of the holding part 91a.

  The light receiving unit 92 includes a light receiving unit lens 92b as a second transparent member formed from a member having translucency, and a holding unit 92a having a light receiving element 92c such as a phototransistor in the cavity. The light receiving unit lens 92b condenses the reflected light reflected by the recording paper 6 on the light receiving element and seals the cavity of the holding unit 92a.

  In the charging train, the cover portion 93 is formed of a member that is easily charged to the minus side due to friction with air, and the light emitting portion lens 91b and the light receiving portion lens 92b are formed of members that are easily charged to the plus side due to friction with air. Is done. In the present embodiment, for example, the cover portion 93 is made of polyester, polyethylene, polystyrene, polypropylene, acrylic, vinyl chloride, Teflon (registered trademark), and the like, and the light emitting portion lens 91b and the light receiving portion lens 92b are made of glass or the like. Is done.

  Airflow is generated by the movement of the carriage 4 in the main scanning direction X and the conveyance of the recording paper 6. Therefore, as shown in FIG. 8B, the cover portion 93 is charged to the minus side due to friction with air, and the light emitting portion lens 91b and the light receiving portion lens 92b are charged to the plus side due to friction with air.

  Accordingly, repulsive force is generated between the positively charged light emitting unit lens 91b and the light receiving unit lens 92b and the positively charged mist 202, so that the mist 202 adheres to the light emitting unit lens 91b and the light receiving unit lens 92b. It is suppressed.

  In addition, since an attractive force is generated between the negatively charged cover portion 93 and the positively charged mist 202, the mist 202 is located on the inner side (paper end detection unit 90 side) or the outer side (paper end) of the cover portion 93. Adsorbed on the side opposite to the part detection unit 90). As a result, the mist 202 floating in the vicinity of the paper edge detection unit 90 is reduced, so that the mist 202 is prevented from adhering to the light emitting unit lens 91b and the light receiving unit lens 92b.

  FIG. 9B is a perspective view of the cover 95 having a cylindrical outer shape. In this embodiment, the outer shape includes the cover portion 93 having a cubic shape, but the opening 96 has a circular shape when viewed from the vertical direction Z through which light emitted from the light emitting portion 91 and reflected light pass. A cylindrical cover part 95 may be provided, and the light emitting part 91 and the light receiving part 92 may be surrounded.

  As described above, the printer 1 described in this embodiment includes the nozzle 56 in FIG. 2 that ejects ink as a liquid, the pressure chamber 54 that communicates with the nozzle 56, and the ink in the pressure chamber 54 that is driven by the application of a drive signal. The recording head 2 as a liquid ejecting head for ejecting ink from the nozzle 56 by driving the pressure generating means, and the first transparent member from the light emitting element 91c in FIG. 8B. The light emitting unit 91 emits light through the light emitting unit lens 91b, and the light receiving unit 92c receives light through the light receiving unit lens 92b as the second transparent member by the light receiving element 92c. A sheet end detection unit 90 that receives reflected light of the light by the light receiving unit 92 and a cover unit 93 that is a charging member that surrounds the sheet end detection unit 90 are provided.

  The light-emitting unit lens 91b and the light-receiving unit lens 92b are made of a material on the plus side that has the same polarity as the polarity of the drive signal in the charging row, and the cover portion 93 is opposite to the polarity of the driving signal in the charging row. It is composed of materials in the negative order of polarity.

  According to this configuration, since repulsive force is generated between the positively charged mist 202 having the same polarity as the drive signal, the light emitting unit lens 91b, and the light receiving unit lens 92b, the mist 202 is connected to the light emitting unit lens 91b and the light receiving unit. Adhering to the partial lens 92b is suppressed.

  Further, since an attractive force is generated between the positively charged mist 202 having the same polarity as the drive signal and the cover portion 93, the mist 202 is drawn toward the cover portion 93, and the mist 202 is attracted to the cover portion 93. There is a high possibility of adhesion. For this reason, since the mist 202 floating in the vicinity of the paper edge detection unit 90 decreases, it is possible to suppress the mist 202 from adhering to the light emitting unit lens 91b and the light receiving unit lens 92b. Accordingly, it is possible to suppress a decrease in detection accuracy by the paper edge detection unit 90.

  Further, the cover portion 93 may be grounded to the ground by making the surface conductive, for example, using a conductive plastic or coating the surface with a conductive material. Thereby, even when there is no friction with air, for example, when the operation is stopped, the cover portion 93 has no electric potential because it falls to the ground, and is at least minus the mist plus charge, so the mist and the cover portion An attractive force can always be generated during 93.

  In the present embodiment, the paper edge detection unit has been described as the optical detection unit. However, the present invention may be applied to the linear sensor unit 18 in FIG. 1B as the optical detection unit. That is, the linear sensor unit 18 is provided with a cover unit that covers the light emitting unit 19 and the light receiving unit 20, and the lens of the light emitting unit 19 and the lens of the light receiving unit 20 are in the same order as the polarity of the drive signal in the charge train. The cover portion that covers the light emitting portion 19 and the light receiving portion 20 is made of a material in the negative order, which is the opposite polarity to the polarity of the drive signal in the charging train.

  Further, the present invention may be applied to the rotary sensor unit 40 of FIG. 6B as an optical detection unit. That is, the rotary sensor unit 40 is provided with a cover unit that covers the light emitting unit 86 and the light receiving unit 87, and the lens of the light emitting unit 86 and the lens of the light receiving unit 87 are in the same order as the polarity of the drive signal in the charge train. The cover portion that covers the light-emitting portion 86 and the light-receiving portion 87 is made of a material that is in the order of the minus side having the opposite polarity to the polarity of the drive signal in the charge train.

(Embodiment 2)
In the first embodiment, the opening portion 94 is provided in the cover portion 93. In the second embodiment, a printer provided with a transparent member at a position facing the light emitting portion lens 91b and the light receiving portion lens 92b will be described.

  FIG. 10A is a view as seen from the sub-scanning direction Y, and shows the paper edge detection unit 90, the cover 93, and the transparent member 97 as the third transparent member in the second embodiment. FIG. 10A is a view in which a transparent member 97 is provided in a portion where the opening 94 in FIG. 8B is formed. The paper edge detection unit 90 has the same configuration as that described in the first embodiment. The paper edge detection unit 90 is provided at the lower end in the vertical direction Z of the carriage 4 on the upstream side of the carriage 4 in the sub-scanning direction Y.

  The transparent member 97 is held by the cover portion 93 with the periphery joined to the cover portion 93. The transparent member 97 is disposed at a position facing the light emitting unit lens 91b and the light receiving unit lens 92b. The light emitted (emitted) from the light emitting unit 91 passes through the transparent member 97, is reflected by the recording paper 6, and passes through the transparent member 97 again as reflected light and is received by the light receiving unit 92.

  As in the first embodiment, the light emitting unit lens 91b and the light receiving unit lens 92b are made of a material (for example, glass) in the order of the plus side having the same polarity as that of the drive signal in the charging train, and the cover unit 93 is In the electrification row, it is made of a material (for example, polyester) that is in the order of the minus side having the opposite polarity to the polarity of the drive signal.

  When an air flow is generated due to movement of the carriage 4 in the main scanning direction X or conveyance of the recording paper 6, the cover portion 93 is charged to the negative side due to friction with air, and the light emitting portion lens 91b and the light receiving portion lens 92b are Charges positively by friction with air.

  As a result, a repulsive force is generated between the positively charged mist 202 having the same polarity as that of the drive signal and the light emitting unit lens 91b and the light receiving unit lens 92b, so that the mist 202 is applied to the light emitting unit lens 91b and the light receiving unit lens 92b. Adhesion is suppressed.

  In the present embodiment, a transparent member 97 made of a material (for example, glass) that is in the order of the plus side, which is the same polarity as the polarity of the drive signal in the charging train, is opposed to the light emitting unit lens 91b and the light receiving unit lens 92b. The cover portion 93 is held and provided at a position to be operated.

  As a result, repulsive force is generated between the positively charged mist 202 having the same polarity as that of the drive signal and the transparent member 97, so that the mist 202 is prevented from adhering to the transparent member 97.

  In addition, as described above, the cover portion 93 is made of a material in the order of the minus side, which is the opposite polarity to the polarity of the drive signal in the charging train, so that the positively charged mist 202 is attracted to the cover portion 93. And is likely to adhere to the cover portion 93.

  Therefore, since the mist 202 floating in the vicinity of the transparent member 97 is reduced, the mist 202 is suppressed from adhering to the transparent member 97. As a result, the light emitted from the light emitting unit 91 and the amount of reflected light are suppressed from being reduced by the transparent member 97, and the detection accuracy for detecting the end of the recording paper 6 by the paper end detecting unit 90 is reduced. Can be suppressed. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

(Embodiment 3)
In the first embodiment and the second embodiment, the light emitting unit lens 91b and the light receiving unit lens 92b are formed by members that are in the positive order in the charging column. However, the light emitting unit lens, A light receiving unit lens may be formed.

  FIG. 10B is a diagram viewed from the sub-scanning direction Y, and is a diagram illustrating the paper edge detection unit 100, the cover unit 93, and the transparent member 97 according to the third embodiment. The cover 93 and the transparent member 97 as the third transparent member are the same as those described in the second embodiment. The paper edge detection unit 100 includes a light emitting unit 101 and a light receiving unit 102.

  The light emitting unit 101 includes a light emitting unit lens 101b as a first transparent member formed of a member having translucency, and a holding unit 101a having a light emitting element 101c such as a light emitting diode in a cavity. The light receiving unit 102 includes a light receiving unit lens 102b as a second transparent member formed of a light-transmitting member, and a holding unit 102a having a light receiving element 102c such as a phototransistor in a cavity. In the present embodiment, the light emitting unit lens 101b and the light receiving unit lens 102b are formed of members that do not define the order in the charging column.

  As in the second embodiment, the transparent member 97 is made of a material (for example, glass) in the order of the plus side that is the same polarity as the polarity of the drive signal in the charge train, and the cover portion 93 is driven in the charge train. It is comprised from the material (for example, polyester) in the order | rank of the minus side which is a polarity opposite to the polarity of a signal.

  Thus, when an air flow is generated, the cover 93 is negatively charged and the transparent member 97 is positively charged due to friction with air. Therefore, there is a high possibility that the mist 202 adheres to the cover portion 93, and the mist adheres to the transparent member 97 is suppressed. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

(Embodiment 4)
In the fourth embodiment, a printer having a configuration that slides with a cover portion and removes mist attached to the cover portion will be described. FIG. 11A is a perspective view of the cover 121 in the fourth embodiment and the transparent member 122 as the third transparent member as viewed from the platen 5 side. The transparent member 122 is located at the center in the sub-scanning direction Y and is held by the cover 121.

  FIG. 11B is a perspective view of the sliding portion 130. The sliding part 130 includes a fixing member 138, holding members 134, 135, 136, a first sliding part 132, and second sliding parts 131, 133.

  The sliding part 130 has a longitudinal direction along the sub-scanning direction Y. The first sliding part 132 is located in the center part in the sub-scanning direction Y, and the second sliding parts 131 and 133 are located on both sides of the first sliding part 132 in the sub-scanning direction Y.

  The 1st sliding part 132 and the 2nd sliding parts 131 and 133 are comprised from the some rod-shaped member 137 which has electroconductivity and has flexibility. The first sliding part 132 is held by a holding member 135 having conductivity, and the second sliding parts 131 and 133 are held by holding members 134 and 136 having conductivity, respectively. The first sliding part 132 and the second sliding parts 131 and 133 held by the holding members 134 to 136 form a so-called brush. The holding members 134, 135, and 136 are fixed to a non-conductor fixing member 138.

  The sliding portion 130 is provided on the platen 5 side so as to be movable in the vertical direction in the vertical direction Z. When the sliding portion 130 is in the upper position, when the carriage 4 moves in the main scanning direction X, the first sliding portion 132 slides on the surface 122a of the transparent member 122 in FIG. Two sliding portions 131 and 133 are slidable on the surfaces 121 a and 121 b of the cover portion 121.

  FIG. 12 is a diagram viewed from the main scanning direction X, and is a schematic diagram illustrating the sheet end detection unit 100, the cover unit 121, the transparent member 122, and the sliding unit 130 in the fourth embodiment. The paper edge detection unit 100 has the same configuration as that described in the third embodiment. The transparent member 122 is made of a material such as glass in the order of the plus side, which is the same polarity side as the polarity of the drive signal in the charging train.

  The cover portion 121 is made of a material such as polyester, acrylic, vinyl chloride, or Teflon (registered trademark) that is in the negative order of the polarity of the drive signal in the charge train. Accordingly, when an air flow is generated by the movement of the carriage 4 or the like, the transparent member 122 is positively charged and the cover portion 121 is negatively charged.

  A negative potential is applied to the first sliding portion 132 via the holding member 135, and a positive potential is applied to the second sliding portions 131 and 133 via the holding members 134 and 136.

  When the carriage 4 is moved in the main scanning direction X in a state where the sliding portion 130 is moved upward in the vertical direction Z, the first sliding portion 132 that is negatively charged becomes the surface of the transparent member 122 that is positively charged. The second sliding portions 131 and 133 that slide with 122a and are positively charged slide with the surfaces 121a and 121b of the cover portion 121 that is negatively charged.

  As described above, in the printer described in the present embodiment, the first sliding portion 132 that slides on the transparent member 122 by applying a negative potential that is a potential opposite to the polarity of the driving signal, and the polarity of the driving signal is the same. And a second sliding part 131, 133 that slides on the cover part 121 by applying a positive potential which is a polar potential.

  According to this configuration, the first sliding part 132 and the second sliding parts 131 and 133 slide with the transparent member 122 and the cover part 121, respectively, so that the mist 202 attached to the transparent member 122 and the cover part 121 is removed. Remove. Further, the transparent member 122 is strongly charged by a plus having the same polarity as the polarity of the drive signal, and the cover portion 121 is strongly charged by a minus having a polarity opposite to the polarity of the drive signal.

  As a result, the repulsive force between the positively charged mist 202 having the same polarity as that of the drive signal and the transparent member 122 as the third transparent member is increased, so that the mist 202 is prevented from adhering to the transparent member 122. it can. Further, since the attractive force between the positively charged mist 202 and the cover part 121 is increased, the amount attached to the cover part 121 is increased. Therefore, the mist 202 floating in the vicinity of the transparent member 122 is reduced, and the mist 202 can be prevented from adhering to the transparent member 122.

  The light-emitting unit lens 101b included in the light-emitting unit 101 and the light-receiving unit lens 102b included in the light-receiving unit 102 may be made of a material in the positive order having the same polarity as the polarity of the drive signal in the charging train. Thereby, since repulsive force is generated between the light emitting unit lens 101b and the light receiving unit lens 102b and the positively charged mist, it is possible to suppress the mist from adhering to the light emitting unit lens 101b and the light receiving unit lens 102b.

  The first sliding portion 132 and the second sliding portions 131 and 133 of this embodiment are composed of a plurality of flexible rod-shaped members. However, as shown in FIG. The part 142 and the second sliding parts 141 and 143 may be a sliding part 140 formed of a flexible plate-like member such as rubber. The 1st sliding part 142 and the 2nd sliding parts 141 and 143 perform the electroconductive process which coats the metal material which has electroconductivity on the surface, and have electroconductivity.

  The first sliding portion 142 is held by a holding member 145 having conductivity, and the second sliding portions 141 and 143 are held by holding members 144 and 146 having conductivity. The first sliding portion 142 and the second sliding portions 141 and 143 are fixed to the fixing member 147, and the sliding portion 140 is movable up and down in the vertical direction Z. Other configurations of the printer in the present embodiment are the same as the configurations of the printer 1 described in the first embodiment.

  In the present embodiment, a negative potential is applied to the first sliding portion 132 and a positive potential is applied to the second sliding portions 131 and 133, but the first sliding portion 132, the second sliding portion 131, Without applying a potential to 133, the first sliding portion 132 is made of a negative charging member such as acrylic fiber, and the second sliding portions 131 and 133 are made of a positive charging member such as nylon fiber or silk. May be.

(Embodiment 5)
In the fourth embodiment, the first sliding part 132 and the second sliding parts 131 and 133 slide with the transparent member 122 and the cover part 121, respectively, thereby removing the mist 202 attached to the transparent member 122 and the cover part 121. However, a member that moves below the transparent member 122 and the cover 121 without contacting the transparent member 122 and the cover 121 may be provided.

  FIG. 13 is a diagram viewed from the main scanning direction X, and is a schematic diagram illustrating the sheet end detection unit 100, the cover unit 121, the transparent member 122, and the moving unit 150 according to the fifth embodiment. The paper edge detection unit 100, the cover unit 121, and the transparent member 122 are the same as those described in the fourth embodiment.

  The moving part 150 includes first moving members 151 and 153 provided at positions facing the cover part 121 and a second moving member 152 provided at a position facing the transparent member 122. A positive potential is applied to the first moving members 151 and 153. A negative potential is applied to the second moving member 152. The moving unit 150 moves below the cover unit 121 and the transparent member 122 in the main scanning direction X without contacting the cover unit 121 and the transparent member 122.

  Thereby, an induced potential can be generated, and the chargeability of the transparent member 122 and the cover part 121 can be increased.

  Without applying a potential to the first moving members 151 and 153 and the second moving member 152, the second moving member 152 is constituted by a negative charging member such as polyethylene or polypropylene, and the first moving members 151 and 153 are made of nylon or glass. You may comprise by positive charging members, such as.

(Embodiment 6)
FIG. 14A is a diagram showing that the charging member 300 is provided in the vicinity of the paper edge detection unit 90 in the sixth embodiment. The configuration of the paper edge detection unit 90 is the same as that described in the first embodiment.

  The charging member 300 is provided on both sides of the paper edge detection unit 90 in the main scanning direction X of the carriage 4. The height of the charging member 300 in the vertical direction Z from the carriage 4 is substantially the same as the height of the paper edge detection unit 90. The charging member 300 is a member that is charged by friction with air.

  The light-emitting unit lens 91b and the light-receiving unit lens 92b in the paper edge detection unit 90 are formed of glass or the like that is on the plus side in the charge train. The charging member 300 is made of a material such as polyester, acrylic, vinyl chloride, or Teflon (registered trademark) that is in the negative order in the charging column. Accordingly, when an air flow is generated by the movement of the carriage 4 or the like, the light emitting unit lens 91b and the light receiving unit lens 92b of the paper edge detection unit 90 are positively charged, and the charging member 300 is negatively charged.

  Therefore, there is a high possibility that the mist 301 adheres to the charging member 300, and the mist 301 is prevented from adhering to the light emitting unit lens 91b and the light receiving unit lens 92b.

  As shown in FIG. 14B, a charging member 302 having a height in the vertical direction Z from the carriage 4 that is higher than that of the paper edge detection unit 90 may be provided. Further, as shown in FIG. 14C, a charging member 303 whose length in the main scanning direction X is longer than the height in the vertical direction Z may be provided.

  FIG. 15A is an enlarged cross-sectional view of the charging member 303a viewed from the sub-scanning direction Y. FIG. The charging member 303a is provided in the vicinity of the light emitting unit lens 91b and the light receiving unit lens 92b. As shown in FIG. 15A, a plurality of uneven portions 304 may be provided on the surface of the charging member 303a.

  FIG. 15B is an enlarged external view of the charging member 303b viewed from the sub-scanning direction Y. The charging member 303b is provided in the vicinity of the light emitting unit lens 91b and the light receiving unit lens 92b. As shown in FIG. 15B, a plurality of ribs 305 having protrusions extending on the surface of the charging member 303b may be provided.

  As described above, by providing the charging members 303a and 303b with the plurality of concave and convex portions 304 and the plurality of ribs 305, the surface area of the charging member is increased. It is suppressed that mist 301 adheres to 92b.

  In the linear sensor unit 18 and the rotary sensor unit 40 described in the first embodiment, the light emitting units 19 and 86 and the light receiving units 20 and 87 are arranged so as to face each other, but reflection of light emitted from the light emitting units 19 and 86 is reflected. The light may be arranged to be received by the light receiving units 20 and 87.

  In the first to fifth embodiments, the printer 1 that performs recording by moving the carriage 4 on which the recording head 2 is mounted in the main scanning direction X has been described. However, the present invention is a direction that intersects the direction in which the recording paper 6 is conveyed. The present invention is also applied to a recording apparatus that includes a recording head in which nozzles are arranged over the entire width of the recording area in the (main scanning direction X) and forms an image on the recording paper 6.

  In the above embodiment, the so-called longitudinal vibration type piezoelectric vibrator 46 is exemplified as the pressure generating means. However, the pressure generation means is not limited thereto, and for example, a so-called flexural vibration type piezoelectric vibrator may be employed. . In this case, the waveform of the drive signal (ejection drive pulse DP) illustrated in FIG. 5 is a waveform in which the direction of potential change, that is, the top and bottom are inverted. In addition, the pressure generation means includes a heating element that causes pressure fluctuations by causing ink to boil by heat generation, an electrostatic actuator that causes pressure fluctuations by displacing the partition walls of the pressure chamber by electrostatic force, etc. The present invention can also be applied to a configuration employing pressure generating means driven by application.

  The present invention is not limited to a printer as long as it is a liquid ejecting apparatus capable of controlling the ejection of liquid using a pressure generating means, and various ink jet recording apparatuses and recording apparatuses such as a plotter, a facsimile machine, and a copying machine. The present invention can also be applied to other liquid ejecting apparatuses such as a display manufacturing apparatus, an electrode manufacturing apparatus, and a chip manufacturing apparatus. In the display manufacturing apparatus, a solution of each color material of R (Red), G (Green), and B (Blue) is ejected from the color material ejecting head. Moreover, in an electrode manufacturing apparatus, a liquid electrode material is ejected from an electrode material ejection head. In the chip manufacturing apparatus, a bioorganic solution is ejected from a bioorganic ejecting head.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording head, 4 ... Carriage, 46 ... Piezoelectric vibrator, 54 ... Pressure chamber, 56 ... Nozzle, 90, 100 ... Paper edge detection part, 91, 101 ... Light emission part, 91b, 101b ... Light emission Lens, 91c, 101c ... light emitting element, 92, 102 ... light receiving part, 92b, 102b ... light receiving part lens, 92c, 102c ... light receiving element, 93, 121 ... cover part, 97, 122 ... transparent member, 130, 140 ... Sliding part, 131, 133, 141, 143 ... second sliding part, 132, 142 ... first sliding part, 300, 302, 303 ... charging member.

Claims (7)

A liquid ejecting head for ejecting liquid;
A light-emitting unit that emits light from the light-emitting element through the first transparent member; and a light-receiving unit that receives light from the light-receiving element through the second transparent member, and that reflects the light emitted from the light-emitting unit. An optical detector that receives light by
A charging member provided in the optical detection unit and charged by friction with air;
The first transparent member and the second transparent member are made of a material in the order of the same polarity as the polarity of mist generated when the liquid is ejected from the liquid ejecting head in the charging train.
The liquid ejecting apparatus according to claim 1, wherein the charging member is made of a material in an order of a polarity opposite to the polarity of the mist in the charging row. The liquid ejecting apparatus according to claim 1,
The liquid ejecting apparatus according to claim 1, wherein the charging member is a cover that surrounds the optical detection unit. The liquid ejecting apparatus according to claim 2,
The first transparent member, the second transparent member is opposed to the third transparent member held by the cover portion,
The liquid ejecting apparatus according to claim 1, wherein the third transparent member is made of a material that is in the same order as the polarity of the mist in the charge train. A liquid ejecting head for ejecting liquid;
A light-emitting unit that emits light from the light-emitting element through the first transparent member; and a light-receiving unit that receives light from the light-receiving element through the second transparent member, and that reflects the light emitted from the light-emitting unit. An optical detector that receives light by
A cover portion surrounding the optical detection unit;
A third transparent member facing the first transparent member and the second transparent member and held by the cover part,
The third transparent member is made of a material in the same order as the polarity of the mist generated when the liquid is ejected from the liquid ejecting head in the charging train, and the cover portion is in the charging train, A liquid ejecting apparatus comprising a material in the order of polarity opposite to the polarity of the mist. The liquid ejecting apparatus according to claim 3 or 4,
A first sliding part that is applied with a potential having a polarity opposite to the polarity of the mist and slides with the third transparent member;
A liquid ejecting apparatus comprising: a second sliding portion that is applied with a potential having the same polarity as the mist and slides on the cover portion. The liquid ejecting apparatus according to any one of claims 2 to 5,
The liquid ejecting apparatus according to claim 1, wherein the cover part is conductive, and the cover part is grounded. A liquid ejecting head for ejecting liquid;
A light-emitting unit that emits light from the light-emitting element through the first transparent member; and a light-receiving unit that receives light from the light-receiving element through the second transparent member, and that reflects the light emitted from the light-emitting unit. An optical detector that receives light by
A charging member provided in the optical detection unit and charged by friction with air;
The first transparent member and the second transparent member are made of a material on the same side as the polarity of mist generated when the liquid is ejected from the liquid ejecting head from the charging member in the charging train. A liquid ejecting apparatus.

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