JP2015164793A - Image formation device, discharge detection unit, and liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a waste liquid transferred to a wipe member is dropped from an end part or deposits and grows to contact with a nozzle surface when the liquid adhering to an impact member is wiped with the wipe member.SOLUTION: A discharge detection unit 100 includes a box shaped holder member 103. An island-like electrode holding part 104 is formed in the holder member 103. An electrode plate 101 is disposed on an upper surface of the electrode holding part 104 which faces a nozzle surface 41 of a recording head 4. A waste liquid receiving part 110 is formed by a groove formed in an area of the holder member 103 which is located between a periphery of the island-like electrode holding part 104 and an outer wall part 103a.

Description

  The present invention relates to an image forming apparatus, a discharge detection unit, and a liquid discharge apparatus.

  As an image forming apparatus such as a printer, a facsimile, a copying apparatus, a plotter, and a complex machine of these, for example, an ink jet recording apparatus is known as an image forming apparatus using a liquid ejecting apparatus including a liquid ejecting head for ejecting ink droplets. Yes.

  In such an image forming apparatus, a discharge detection device that detects a droplet discharge state from the head is provided, and when a nozzle that does not perform normal droplet discharge is detected, a head maintenance operation such as cleaning of the nozzle surface is performed. I have something to do.

  As a conventional ejection detection device, for example, ejection / non-ejection is detected by ejecting droplets from a recording head toward an electrode plate and measuring an electrical change when the droplets land on the electrode plate. What was made is known (patent document 1).

  In addition, there is also known one in which the electrode plate is cleaned by a wiping member that wipes in the same direction as the carriage movement direction (Patent Document 2).

Japanese Patent No. 4735120 JP 2004-306475 A

  When droplets are ejected onto a landing member such as the electrode plate described above and an electrical change of the landing member is read to detect the presence or absence of ejection, the droplet adheres to the landing member upon detection of ejection. Become. Therefore, as disclosed in Patent Document 2, cleaning is performed by wiping the landing surface with a wiping member.

  However, in the configuration disclosed in Patent Document 2, when the landing member is wiped with the wiping member, the liquid (waste liquid) that has landed on the landing surface flows down around the landing surface, or the same height as the landing surface. There is a problem that when a member is disposed, the material adheres to and accumulates on the member, and deposits come into contact with the landing surface or the nozzle surface to be transferred.

  The present invention has been made in view of the above-described problems, and an object thereof is to prevent problems caused by the accumulation of waste liquid around a landing member.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A liquid discharge head having a plurality of nozzles for discharging droplets;
Discharge detection means for detecting the presence or absence of droplet discharge from the liquid discharge head,
The discharge detection means includes
A landing member that is disposed in a region facing the liquid discharge head and has a landing surface on which droplets discharged from the nozzles of the liquid discharge head land;
Detecting electrical changes caused by the droplets ejected from the nozzles of the liquid ejection head landing on the landing surface, and detecting the presence or absence of the droplet ejection;
A wiping member that wipes and cleans the landing surface of the landing member;
At least the waste liquid receiving portions for receiving the waste liquid of the droplets are provided on both sides of the landing surface in the direction orthogonal to the moving direction of the wiping member.

  According to the present invention, it is possible to prevent problems caused by the accumulation of waste liquid around the landing member.

It is a plane explanatory view of a mechanism part of an example of an image forming apparatus to which the present invention is applied. It is block explanatory drawing with which the outline | summary of the control part of the apparatus is provided. It is explanatory drawing with which it uses for description of 1st Embodiment of this invention. It is a principal part perspective explanatory drawing similarly. It is front explanatory drawing similarly. It is a perspective explanatory view of the same discharge detection unit. It is an isometric view explanatory drawing similarly used for description of the wiper evacuation cover of a cleaning unit. It is an isometric view explanatory drawing used for effect | action description of the wiping operation | movement in the embodiment. 10 is a perspective explanatory view for explaining a comparative example 1. FIG. 10 is an explanatory perspective view for explaining a comparative example 2. FIG. It is a perspective explanatory view of the discharge detection unit in a 2nd embodiment of the present invention. It is principal part front explanatory drawing with which it uses for description of 3rd Embodiment of this invention. It is a plane explanatory view used for description of the relationship of the width of the direction orthogonal to the wiping direction of the electrode plate, wiper member, and waste liquid receiving part in the embodiment. It is explanatory drawing with which it uses for description of the relationship between the length of the nozzle row of the recording head and the length of an electrode plate in 4th Embodiment of this invention. It is a perspective explanatory view of the discharge detection unit in a 5th embodiment of the present invention. It is a perspective explanatory view of the discharge detection unit in a 6th embodiment of the present invention. It is a perspective explanatory view of the discharge detection unit in a 7th embodiment of the present invention. It is an isometric view explanatory drawing of the discharge detection unit in 8th Embodiment of this invention. It is sectional explanatory drawing in alignment with the electrode plate longitudinal direction of the discharge detection unit in 9th Embodiment of this invention. It is explanatory drawing of the nut holding part of the holder member of the discharge detection unit in 10th Embodiment of this invention. It is sectional explanatory drawing in alignment with the electrode plate longitudinal direction of the discharge detection unit in 11th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an image forming apparatus including a liquid ejection apparatus according to the present invention will be described with reference to FIG. FIG. 1 is an explanatory plan view of a mechanism portion of the image forming apparatus.

  This image forming apparatus is a serial type ink jet recording apparatus, and a carriage 3 is movably held by a main guide member 1 and a sub guide member (not shown) horizontally mounted on left and right side plates (not shown). Then, the main scanning motor 5 reciprocates in the main scanning direction (carriage movement direction) via a timing belt 8 spanned between the driving pulley 6 and the driven pulley 7.

  The carriage 3 is mounted with recording heads 4a and 4b (referred to as “recording head 4” when not distinguished), which are liquid ejection heads. For example, the recording head 4 ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). The recording head 4 is mounted with a nozzle row 4n composed of a plurality of nozzles arranged in the sub-scanning direction orthogonal to the main scanning direction and with the droplet discharge direction facing downward.

  The recording head 4 has two nozzle rows in which a plurality of nozzles are arranged. One nozzle row of the recording head 4a discharges black (K) droplets, and the other nozzle row discharges cyan (C) droplets. One nozzle row of the recording head 4b discharges magenta (M) droplets, and the other nozzle row discharges yellow (Y) droplets.

  As the liquid discharge head constituting the recording head 4, for example, a piezoelectric actuator such as a piezoelectric element, or a thermal actuator that uses a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor can be used. .

  On the other hand, in order to transport the paper 10, a transport belt 12, which is transport means for electrostatically attracting the paper and transporting the paper at a position facing the recording head 4, is provided. The transport belt 12 is an endless belt and is stretched between the transport roller 13 and the tension roller 14.

  The transport belt 12 rotates in the sub-scanning direction when the transport roller 13 is rotationally driven by the sub-scanning motor 16 via the timing belt 17 and the timing pulley 18. The conveyor belt 12 is charged (charged) by a charging roller (not shown) while moving around.

  Further, a maintenance / recovery mechanism 20 that performs maintenance / recovery of the recording head 4 on the side of the conveyance belt 12 is arranged on one side of the carriage 3 in the main scanning direction, and the recording head 4 is arranged on the side of the conveyance belt 12 on the other side. The empty discharge receptacles 21 for performing empty discharge are respectively disposed.

  The maintenance / recovery mechanism 20 includes, for example, a cap member 20a for capping the nozzle surface (surface on which the nozzles are formed) of the recording head 4, a wiper member 20b for wiping the nozzle surface, and an empty space (not shown) for discharging liquid droplets that do not contribute to image formation. It consists of a discharge receptacle.

  In addition, the discharge detection unit 100 constituting the discharge detection unit according to the present invention is arranged outside the recording area between the transport belt 12 and the maintenance / recovery mechanism 20 and in the area that can face the recording head 4. Yes.

  On the other hand, the carriage 3 is provided with a cleaning unit 200 which is a cleaning means for cleaning an electrode plate 101 (to be described later) of the discharge detection unit 100.

  An encoder scale 23 having a predetermined pattern is disposed between both side plates along the main scanning direction of the carriage 3. The carriage 3 is provided with an encoder sensor 24 composed of a transmissive photosensor that reads the pattern of the encoder scale 23. Provided. These encoder scale 23 and encoder sensor 24 constitute a linear encoder (main scanning encoder) that detects the movement of the carriage 3.

  Further, a code wheel 25 is attached to the shaft of the transport roller 13 and an encoder sensor 26 including a transmission type photo sensor for detecting a pattern formed on the code wheel 25 is provided. These code wheel 25 and encoder sensor 26 constitute a rotary encoder (sub-scanning encoder) that detects the amount and position of movement of the conveyor belt 12.

  In this image forming apparatus configured as described above, the sheet 10 is fed from the sheet feeding tray (not shown) onto the charged conveying belt 12 and sucked, and the sheet 10 is moved in the sub-scanning direction by the circular movement of the conveying belt 12. Be transported.

  Therefore, by driving the recording head 4 according to the image signal while moving the carriage 3 in the main scanning direction, ink droplets are ejected onto the stopped paper 10 to record one line. Then, after the sheet 10 is conveyed by a predetermined amount, the next line is recorded.

  Upon receiving a recording end signal or a signal that the trailing edge of the paper 10 has reached the recording area, the recording operation is finished, and the paper 10 is discharged to a paper discharge tray (not shown).

  Next, an outline of the control unit of the image forming apparatus will be described with reference to FIG. FIG. 2 is an explanatory block diagram of the entire control unit.

  The control unit 500 includes a main control unit 500A including a CPU 501 that controls the entire apparatus, a ROM 502 that stores programs executed by the CPU 501 and other fixed data, and a RAM 503 that temporarily stores image data and the like. Yes.

  Further, the control unit 500 includes a host I / F 506 that controls data transfer with a host (information processing apparatus) 600 such as a PC, an image output control unit 511 that drives and controls the recording head 4, and an encoder analysis unit 512. It has. The encoder analysis unit 512 inputs and analyzes detection signals from the main scanning encoder sensor 24 and the sub-scanning encoder sensor 26.

In addition, the control unit 500 includes a main scanning motor driving unit 513 that drives the main scanning motor 5, a sub scanning motor driving unit 514 that drives the sub scanning motor 16, an I / O 516 between various sensors and actuators 517, and the like. It also has.
It has.

  In addition, the control unit 500 includes a discharge detection unit 531 that measures (detects) an electrical change when a droplet reaches the electrode plate 101 of the discharge detection unit 100 to determine discharge / non-discharge. In addition, the control unit 500 includes a cleaning unit drive unit 532 that drives the drive motor 203 of the cleaning unit 200 that wipes the electrode plate 101 of the discharge detection unit 100.

  The image output control unit 511 includes data generation means for generating print data, drive waveform generation means for generating a drive waveform for driving and controlling the recording head 4, and head control signal for selecting a required drive signal from the drive waveform. And data transfer means for transferring print data. Then, a drive waveform, a head control signal, print data, and the like are output to a head driver 510 which is a head drive circuit for driving the recording head 4 mounted on the carriage 3 side, and printing is performed from the nozzles of the recording head 4. Droplets are ejected according to the data.

  The encoder analysis unit 512 includes a direction detection unit 520 that detects the movement direction from the detection signal, and a counter unit 521 that detects the movement amount.

  The control unit 500 controls the movement of the carriage 3 by controlling the driving of the main scanning motor 5 via the main scanning motor driving unit 513 based on the analysis result from the encoder analyzing unit 512. Further, the feeding control of the paper 10 is performed by controlling the driving of the sub-scanning motor 16 via the sub-scanning motor driving unit 514.

  When performing droplet ejection detection of the recording head 4, the main control unit 500 </ b> A of the control unit 500 moves the recording head 4 to eject droplets from the required nozzles of the recording head 4 to detect from the ejection detection unit 531. Control is performed to determine the droplet discharge state based on the signal.

  Next, a first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is an explanatory diagram for explaining the embodiment, FIG. 4 is an explanatory perspective view of the main part, FIG. 5 is an explanatory front view of the same, FIG. 6 is an explanatory perspective view of the discharge detection unit, and FIG. It is an isometric view explanatory drawing used for description of a retraction | saving cover.

  The discharge detection unit 100 includes a box-shaped holder member 103, and an electrode holding portion 104 that is an island-shaped landing member holding portion is formed in the holder member 103. An electrode plate (electrode member) 101 which is a landing member is held and arranged on the upper surface of the electrode holding unit 104 which can face the nozzle surface 41 of the recording head 4. The surface (opposite surface) of this electrode plate 101 is a landing surface for ejection detection.

  The holder member 103 is made of an insulating material such as plastic.

  The electrode plate 101 is a conductive metal plate, and is preferably formed of a material that is not easily rusted and hardly deteriorates with respect to ink. The electrode plate 101 can be formed of, for example, SUS304, a copper alloy with Ni plating, or Pd plating. Further, it is preferable to perform a water repellent treatment on the surface of the electrode plate 101 on which the droplets land.

  A lead wire 102 which is a wiring member drawn out to the outside is electrically connected to the electrode plate 101, and is connected to the discharge detection unit 531.

  The waste liquid receiving part 110 is formed by a groove formed between the periphery of the island-shaped electrode holding part 104 of the holder member 103 and the outer wall part 103a. That is, the waste liquid receiving part integrated with both sides of the end (side) in the direction intersecting the wiping direction of the wiper member 202 which is the wiping member of the rectangular electrode plate 101, and the wiping start side and the wiping end side in the wiping direction, respectively. 110 is formed (reference numbers are shown in four places for clarity).

  Further, the outer wall portion on the wiping direction end side by the wiper member 202 of the holder member 103 forms a wiper cleaner 111 which is a cleaning member for removing waste liquid (droplets attached to the wiper member 202) from the wiper member 202 and cleaning it. ing.

  The holder member 103 is connected to a waste liquid tube 112 that forms a flow path from the lower side of the waste liquid receiving portion 110 to a waste liquid tank (not shown). Although not shown, a suction pump is disposed on the flow path leading to the waste liquid tank, and the waste liquid accumulated at the bottom of the waste liquid receiving unit 110 is discharged to the waste liquid tank.

  On the other hand, the carriage 3 is provided with a cleaning unit 200 which is a cleaning unit including a wiper member 202 which is a wiping member for wiping off droplets attached to the surface (landing surface) of the electrode plate 101.

  The wiper member 202 is made of, for example, EPDM. EPDM is not so high in water repellency, and the water repellency on the surface of the electrode plate 101 can be higher than the water repellency of the wiper member 202. By making the water repellency on the surface of the electrode plate 101 higher than the water repellency of the wiper member 202, it becomes easier to wipe ink from the electrode plate 101.

  The wiper member 202 is attached to a timing belt 223 that is wound around the drive pulley 221 and the driven pulley 222. Then, the drive pulley 221 is rotated through the worm gear 224 and the gear 225 by the drive motor 203 which is a drive source attached to the carriage 3, so that the wiper member 202 circulates along with the timing belt 223 in the direction of arrow A in FIG. Moving.

  Further, a wiper retracting cover 204 that covers the wiper member 202 at the retracted position is provided. When the wiper member 202 is not used, the wiper member 202 is stored in the wiper retracting cover 204. Thereby, it is possible to prevent a small amount of waste liquid adhering to the wiper member 202 from being scattered during the carriage operation.

  As shown in FIG. 7, the wiper retracting cover 204 serves as a waste liquid receiving portion 204a that receives waste liquid that hangs down from the wiper member 202. The waste liquid receiving portion 204a is provided with an absorbing member 207 that absorbs and holds the waste liquid. Yes.

  The effect | action regarding the wiping operation | movement in this embodiment comprised in this way is demonstrated with reference also to FIG. FIG. 8 is a perspective view for explaining the same.

  Although details will be described later in the ejection detection operation, the presence or absence of droplet ejection is detected by an electrical change when droplets are ejected onto the electrode plate 101 one nozzle at a time.

  Since the droplets 120 remain on the electrode plate 101 by this discharge detection operation, as shown in FIG. 8, the wiping operation (cleaning) is performed by moving the wiper wiper member 202 in the nozzle arrangement direction to wipe the droplets 120 and cleaning them. Operation).

  At this time, the waste liquid 300 of liquid droplets transferred to the wiper member 202 may drop from the end of the wiper member 202 in the width direction (direction intersecting the wiping direction). And will not fall into the device. Further, it does not accumulate due to being received by the waste liquid receiving unit 110 and re-transferred to the wiper member 202 or contact with the nozzle surface 41.

  Here, the malfunction regarding the wiping operation | movement in a comparative example is demonstrated with reference to FIG.9 and FIG.10. FIG. 9 is an explanatory perspective view for explaining the first comparative example, and FIG. 10 is an explanatory perspective view for explaining the second comparative example. In addition, the same code | symbol is attached | subjected to the part corresponding to this embodiment, and description is simplified.

  In Comparative Example 1, the electrode plate 1101 is held by a holder member 1103 corresponding to the holder member 103 including the electrode holding portion 104 of the embodiment. A waste liquid receiving portion 1110 having a wider width in the direction orthogonal to the wiping direction than the electrode plate 1101 is provided on the wiping direction end side of the wiper member 202.

  In such a configuration, when the wiper member 202 is moved in the nozzle arrangement direction and the droplet 120 landed on the surface of the electrode plate 1101 is wiped and removed, the waste liquid transferred to the wiper member 202 has the wiping direction. The waste liquid 300 is dropped from the end in the intersecting direction. As a result, there is a problem that the inside of the apparatus becomes dirty.

  Further, the waste liquid transferred from the wiper member 202 may adhere to the deposit 301 at the connecting portion between the electrode plate 1101 and the waste liquid receiving portion 1110. When the deposit 301 grows, it re-transfers to the wiper member 202 and the wiping performance deteriorates, or it contacts the nozzle surface of the recording head 4 to destroy the meniscus, thereby causing an ejection failure.

  In Comparative Example 2, in the configuration of Comparative Example 1, a rib 1111 having a height similar to that of the electrode plate 101 is further provided in the middle of the longitudinal direction (wiping direction) of the electrode plate 101.

  Even in such a configuration, the waste liquid transferred from the wiper member 202 adheres to the rib 1111 and becomes the deposit 301. For this reason, the wiping performance is lowered by re-transferring to the wiper member 202, or the ejection failure is caused by contacting the nozzle surface of the recording head 4 to destroy the meniscus.

  On the other hand, in the present embodiment, the electrode plate 101 is particularly held by the island-shaped electrode holding portion 104 that is separated from the outer wall portion 103 a of the holder member 103. As a result, the entire periphery of the electrode plate 101 becomes the waste liquid receiving portion 110, so that dripping and accumulation of the waste liquid can be prevented, and problems such as those of Comparative Examples 1 and 2 do not occur.

  Here, returning to FIG. 4, an example of the discharge detection unit 531 will be described.

  As shown in FIG. 4, the discharge detection unit 531 includes a high voltage power source 701 that applies a high voltage VE (for example, 750 V) to the electrode plate 101. The high voltage power source 701 is on / off controlled by the main controller 500A.

  In addition, a band-pass filter (BPF) 702 that inputs a signal accompanying an electrical change when a droplet reaches the electrode plate 101, an amplifier (AMP) 703 that amplifies the signal, and A / D-converts the amplified signal. And an AD converter (ADC) 704. The conversion result of the ADC 704 is input to the main controller 500A.

  When performing ejection detection, the nozzle surface 41 of the recording head 4 and the electrode plate 101 are opposed to each other, a high voltage VE is applied to the electrode plate 101, and a potential difference is applied between the nozzle surface 41 and the electrode plate 101. At this time, the nozzle surface 41 of the recording head 4 is negatively charged, and the electrode plate 101 is positively charged.

  In this state, one or more droplets for detection are ejected from the recording head 4 for each nozzle.

  At this time, since the ejected liquid droplets are ejected from the nozzle surface 41 of the recording head 4 that is negatively charged, the liquid droplets are also negatively charged. When this lands on the positively charged electrode plate 101, the voltage of the high voltage VE applied to the electrode plate 101 fluctuates slightly.

  Therefore, the fluctuation (AC component) is extracted by the band pass filter 702, amplified by the amplifier circuit 703, A / D converted by the ADC 704, and input to the main controller 500A as a measurement result (detection result).

  The main control unit 500A determines whether or not the measurement result (variation) exceeds a preset threshold value. If the measurement result exceeds the threshold value, the main control unit 500A determines that ejection is in progress and exceeds the threshold value. If not, it is determined as non-ejection.

  In the present embodiment, since each nozzle is ejected and landed on the electrode plate 101, it takes about 0.5 to 10 msec to determine ejection / non-ejection of one nozzle. After the determination of ejection / non-ejection for all nozzles is completed, the high voltage VE applied to the electrode plate 101 is turned off.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 11 is a perspective explanatory view of the discharge detection unit in the same embodiment.

  In the embodiment, the guide portion 104 a that extends in the wiping direction to the outer wall portion 103 a on the wiping start side and the wiping end side of the wiper member 202 continuously to the electrode holding portion 104 a of the holder member 103 and guides the wiper member 202 is provided. Forming.

  In the direction orthogonal to the wiping direction, the guide portion 104a is disposed at the same position as the end of the electrode plate 101 (may be inside).

  Since it comprised in this way, the movement by the wiping start end and the end end side of the wiper member 202 becomes smooth.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 12 is an explanatory front view of a main part for explaining the embodiment, and FIG. 13 is an explanatory plan view for explaining the relationship between the width of the electrode plate, the wiper member, and the waste liquid receiving part in the direction perpendicular to the wiping direction.

  The width in the direction perpendicular to the moving direction (wiping direction) of the wiper member 202 that is the wiping member is W1, the width in the direction perpendicular to the wiping direction of the surface of the electrode plate 101 that is the landing surface is W2, and the waste liquid receiving unit 110 is wiped When the width in the direction orthogonal to the direction is W3, the relationship is W2 <W1 <W3.

  As a result, the entire surface (landing surface) of the electrode plate 101 can be wiped off, and the waste liquid dripping from both ends of the wiper member 202 can be reliably received by the waste liquid receiver 110.

  Note that the wiper member 202 does not need to be arranged in a posture orthogonal to the wiping direction, and can be arranged to be inclined in the wiping direction as shown in FIG. Even in this case, the width W1 is a width in a direction orthogonal to the wiping direction.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 14 is an explanatory diagram of the relationship between the length of the nozzle row of the recording head and the length of the electrode plate in the embodiment.

  When the length of the nozzle row of the recording head 4 is L1, and the length of the electrode plate 101 is L2, the relationship is L1 <L2.

  Thereby, it is possible to detect droplet discharge for all nozzles without moving the recording head 4 and the electrode plate 101.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 15 is a perspective explanatory view of the discharge detection unit in the same embodiment.

  In this embodiment, the landing surface is the entire surface of the electrode plate 101.

  By using the entire landing surface wiped by the wiper member 202 as an electrode surface, the contact pressure of the wiper member 202 can be made uniform as compared with the case where the landing surface is formed of a member made of a different material.

  In addition, when different types of materials having different landing surfaces are formed, gaps and steps are generated on the boundary surface due to the problem of dimensional accuracy of parts and the difference in thermal contraction rate, and waste liquid tends to accumulate. On the other hand, when the entire landing surface is a single member electrode surface, there are no such gaps or steps, and no waste liquid is deposited.

  Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 16 is a perspective explanatory view of the discharge detection unit in the same embodiment.

  In the present embodiment, the angle formed by the side surface 101a on the wiping start side by the wiper member 202 of the electrode plate 101 and the surface of the electrode plate 101 which is the landing surface is a right angle or an acute angle. However, the side (edge portion) 114 on the wiping start side by the wiper member 202 of the electrode plate 101 has a minute round shape.

  Thereby, the dirt adhering to the wiper member 202 can be scraped off by the edge portion 114, and the electrode surface can be cleaned well.

  In this case, if the edge portion 114 has an acute angle shape or a right angle shape with a sharp tip, the wiper member 202 may be damaged, and therefore, the edge portion 114 has a minute round shape that can exhibit a scraping function.

  Next, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 17 is a perspective explanatory view of the discharge detection unit in the same embodiment.

  In the present embodiment, the curved surface portion 115 is provided on the wiping start side by the wiper member 202. Here, the curved surface portion 115 is formed by the electrode holding portion 104.

  As a result, the wiper member 202 can smoothly move from the wiping start end side to the surface of the electrode plate 101, and vibration noise (so-called chattering) that may occur when the wiper member 202 has an edge portion as in the third embodiment. (Sound) does not occur.

  Next, an eighth embodiment of the present invention will be described with reference to FIG. FIG. 18 is an explanatory perspective view of the discharge detection unit in the same embodiment.

  In the present embodiment, the curved surface shape portion 115 of the seventh embodiment is continuously formed on the landing surface by the electrode plate 101.

  As described above, by forming the landing surface and the curved surface portion with a single electrode member, there is no seam, and accumulation of waste liquid and damage to the wiper member due to the seam can be prevented.

  Next, a ninth embodiment of the present invention will be described with reference to FIG. FIG. 19 is a cross-sectional explanatory view along the longitudinal direction (wiping direction) of the electrode plate of the discharge detection unit in the same embodiment.

  As described above, in the holder member 103, the electrode holding portion 104 that is an island-shaped landing member holding portion that holds the electrode plate 101 that is a landing member is provided.

  One end portion 400 a of the electrode plate 101 is held by the electrode holding portion 104 by a stepped screw member 401 and a nut 402. Note that the one end portion 400a and the other end portion 400b of the electrode plate 101 are portions where no landing surface is formed.

  Further, the round terminal 102a of the lead wire 102, which is a wiring member wound around the electrode plate 101 on the opposite side of the electrode holding portion 104 (outside the holder member 103), is sandwiched between the electrode holding portion 104 by the nut 402. It is fixed. Thereby, the electrode plate 101 and the lead wire 102 are electrically connected through the stepped screw member 401.

  Further, a seal member 403 such as an O-ring is provided at a portion where the stepped screw member 401 passes through the electrode holding portion 104 to prevent the liquid from moving to the lead wire 102 side.

  Here, the other end portion 400 b of the electrode plate 101 is inserted and held in a hook portion 404 provided in the electrode holding portion 104 of the holder member 103.

  Thereby, the height of the electrode plate 101 can be adjusted by adjusting the tightening amount of the stepped screw member 401.

As described above, the landing member is fixed to the holder member with the screw member and held, and the electrode plate and the wiring member wound around the outside of the holder member are electrically connected through the screw member. ,
With a simple configuration, electrical connection to an external wiring member can be performed while holding the landing member.

  Further, as in the present embodiment, by sealing the space between the screw member and the holder member with a seal member, particularly when the surface of the landing member is wiped with the wiping member to be cleaned, the liquid is separated from the landing member. Leakage to the outside through a screw member serving as a connection portion with the wiring member can be prevented and deterioration of the wiring member (such as rust and tearing of the coating) can be prevented, and the life of the device can be extended.

  Further, when the landing member is held by the holder member at two locations, the one end portion side is fixed with a screw member, and the other end portion side is hooked (engaged) and fixed, thereby fixing the number of screw members. This can reduce the man-hours for screw tightening and the cost of parts for screw members.

  Next, a tenth embodiment of the present invention will be described with reference to FIG. FIG. 20 is an explanatory view of a nut holding portion of the holder member of the discharge detection unit in the same embodiment, and corresponds to a portion when FIG. 19 is viewed from the arrow G direction.

  The electrode holding portion 104 of the holder member 103 is provided with a substantially rectangular rotation restricting portion 405 corresponding to the square nut 402 in a plan view for restricting the rotation of the nut 402.

  As a result, when the stepped screw member 401 is tightened, the rotation of the nut 402 is restricted, so that the stepped screw member 401 can be easily tightened.

  Next, an eleventh embodiment of the present invention will be described with reference to FIG. FIG. 21 is a cross-sectional explanatory view along the longitudinal direction (wiping direction) of the electrode plate of the discharge detection unit in the same embodiment.

  In the present embodiment, the electrode plate 101 is formed in a shape that follows the outer peripheral surface (including both side surfaces in the longitudinal direction) of the electrode holding portion 104 with a thin metal plate, and is slightly smaller than the electrode holding portion 104. .

  The one end portion 400a and the other end portion 400b of the electrode plate 101 are fixed to the holder member 103 by screw members 406 and 407, respectively. At this time, the electrode plate 101 is pulled between the fixed portions, and as a result, closely contacts the holder member 103. This makes it possible to stabilize the electrode plate shape.

  One screw member 406 passes through the holder member 103 and is connected to the round terminal 102a of the lead wire 102 in the same manner as in the ninth and tenth embodiments. The other screw member 407 is embedded in the holder member 103.

  In each of the above embodiments, the landing member is an electrode plate. However, the landing member is a resistor (resistive member), and discharge detection is performed by detecting a resistance value change between both ends due to droplet landing. The same applies to what is done.

  In the present application, the “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, and the like, and means a medium to which ink droplets or other liquids can adhere. , Recording media, recording paper, recording paper, and the like. In addition, image formation, recording, printing, printing, and printing are all synonymous.

  The “image forming apparatus” means an apparatus that forms an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics or the like. In addition, “image formation” not only applies an image having a meaning such as a character or a figure to a medium but also applies an image having no meaning such as a pattern to the medium (simply applying a droplet to the medium). It also means to land on.

  The “ink” is not limited to an ink unless otherwise specified, but includes any liquid that can form an image, such as a recording liquid, a fixing processing liquid, or a liquid. Used generically. For example, DNA samples, resists, pattern materials, resins and the like are also included.

  In addition, the “image” is not limited to a planar image, and includes an image given to a three-dimensionally formed image and an image formed by three-dimensionally modeling a solid itself.

3 Carriage 4, 4a, 4b Recording head 41 Nozzle surface 100 Discharge detection unit 101 Electrode plate (electrode member)
DESCRIPTION OF SYMBOLS 103 Holder member 104 Electrode holding part 110 Waste liquid receiving part 200 Cleaning unit 202 Wiper member (wiping member)

Claims (12)

A liquid discharge head having a plurality of nozzles for discharging droplets;
Discharge detection means for detecting the presence or absence of droplet discharge from the liquid discharge head,
The discharge detection means includes
A landing member that is disposed in a region facing the liquid discharge head and has a landing surface on which droplets discharged from the nozzles of the liquid discharge head land;
Detecting electrical changes caused by the droplets ejected from the nozzles of the liquid ejection head landing on the landing surface, and detecting the presence or absence of the droplet ejection;
A wiping member that wipes and cleans the landing surface of the landing member;
An image forming apparatus, wherein at least both sides of the landing surface in a direction orthogonal to the moving direction of the wiping member are provided with a waste liquid receiving portion for receiving the waste liquid of the droplets. The image forming apparatus according to claim 1, wherein the waste liquid receiver is provided over the entire circumference of the landing surface. The landing member is an electrode member,
Applying a potential difference between the nozzle surface of the liquid discharge head and the landing surface, and detecting an electrical change that occurs when a droplet discharged from the nozzle of the liquid discharge head lands on the landing surface, The image forming apparatus according to claim 1, wherein presence or absence of the droplet discharge is detected. The landing member is a resistance member,
3. The presence or absence of the droplet discharge is detected by detecting a change in resistance value that occurs when a droplet discharged from a nozzle of the liquid discharge head lands on the landing surface. Image forming apparatus. The width in the direction orthogonal to the moving direction of the wiping member is W1,
The width of the landing surface in the direction perpendicular to the moving direction of the wiping member is W2,
When the width in the direction orthogonal to the moving direction of the wiping member of the waste liquid receiving portion is W3,
W2 <W1 <W3
The image forming apparatus according to claim 1, wherein the image forming apparatus is related to 6. The image forming apparatus according to claim 1, wherein a length of the landing surface is longer than a length of the row of the plurality of nozzles. The image forming apparatus according to claim 1, wherein the landing member has a right angle or an acute angle formed by a side surface on the wiping start side by the wiping member and the landing surface. The image forming apparatus according to claim 1, wherein a curved surface portion is formed on a wiping start side of the wiping member. The image forming apparatus according to claim 8, wherein the landing surface and the curved surface shape portion are formed of the same member. A discharge detection unit that detects the presence or absence of droplet discharge from a liquid discharge head,
A landing member that is disposed in a region facing the liquid discharge head and has a landing surface on which droplets discharged from the nozzles of the liquid discharge head land;
Detecting electrical changes caused by the droplets ejected from the nozzles of the liquid ejection head landing on the landing surface, and detecting the presence or absence of the droplet ejection;
A wiping member that wipes and cleans the landing surface of the landing member;
Waste liquid receiving portions for receiving the waste liquid of the liquid droplets are provided on both sides in a direction orthogonal to the moving direction of the wiping member for wiping and cleaning at least the landing surface of the landing member, around the landing surface. Discharge detection unit characterized by. A discharge detection unit that detects the presence or absence of droplet discharge from a liquid discharge head,
A landing member that is disposed in a region facing the liquid discharge head and has a landing surface on which droplets discharged from the nozzles of the liquid discharge head land;
Detecting the electrical change caused by the liquid droplets ejected from the nozzles of the liquid ejection head landing on the landing surface, the presence or absence of the droplet ejection is detected,
A holder member for holding the landing member;
At least one end of the landing member is held by the holder member with a screw member;
The discharge detection unit, wherein the landing member and a wiring member wound around the outside of the holder member are connected via the screw member. A liquid discharge head for discharging droplets;
An ejection detection unit that detects the presence or absence of droplet ejection from the liquid ejection head;
A liquid ejection device comprising:
The discharge detection unit includes:
A landing member that is disposed in a region facing the liquid discharge head and has a landing surface on which droplets discharged from the nozzles of the liquid discharge head land;
Detecting electrical changes caused by the droplets ejected from the nozzles of the liquid ejection head landing on the landing surface, and detecting the presence or absence of the droplet ejection;
A wiping member that wipes and cleans the landing surface of the landing member;
A liquid discharge apparatus according to claim 1, wherein a waste liquid receiving portion for receiving the liquid waste liquid is provided at least on both sides of the periphery of the landing surface in a direction orthogonal to the moving direction of the wiping member.

Images