JP6519121B2 - Image forming apparatus, discharge detection unit, liquid discharge apparatus - Google Patents

Description

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

  For example, as an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, and a complex machine thereof, an ink jet recording apparatus is known as an image forming apparatus using a liquid discharge apparatus including a liquid discharge head which discharges ink droplets. There is.

  Such an image forming apparatus includes a discharge detection device that detects a droplet discharge state from the head, and when a nozzle whose droplet discharge is not normal is detected, maintenance and recovery operations of the head such as cleaning of the nozzle surface are performed. There is something that

  As a conventional discharge detection device, for example, a droplet is discharged from a recording head toward an electrode plate, and discharge / non-discharge is detected by measuring an electrical change when the droplet lands on the electrode plate. What was done is known (patent document 1).

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

Patent No. 4735120 gazette JP 2004-306475 A

  When droplets are discharged onto a landing member such as an electrode plate as described above and the electrical change of the landing member is read to detect the presence or absence of the discharge, the droplets adhere to the landing member along with the discharge detection. Become. Therefore, as disclosed in Patent Document 2, the landing surface is wiped and cleaned by the wiping member.

In order to solve the above problems, an image forming apparatus according to the present invention is:
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 is
It has an impacting member which is disposed in an area that can face the liquid ejection head, and has an impacting surface on which the droplets ejected from the nozzle of the liquid ejection head are impacted,
Detecting an electrical change caused by the droplets discharged from the nozzles of the liquid discharge head landing on the landing surface, and detecting the presence or absence of the droplet discharge;
A wiping member that wipes and cleans the landing surface of the landing member;
A wiper cleaner for removing the waste liquid adhering to the wiping member;
A waste liquid receiving portion is provided at least on both sides of the landing surface in a direction orthogonal to the moving direction of the wiping member, spaced from the landing surface, and receiving waste liquid from the droplets.
The wiper cleaner is disposed on an outer wall portion located downstream of the waste liquid receiving portion in the moving direction of the wiping member, and a part of the wiper cleaner is positioned above the landing surface.

  The present invention has been made in view of the above problems, and an object of the present invention is to be able to prevent a defect due to the accumulation of waste liquid around the impact member.

In order to solve the above problems, an image forming apparatus according to the present invention is:
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 is
It has an impacting member which is disposed in an area that can face the liquid ejection head, and has an impacting surface on which the droplets ejected from the nozzle of the liquid ejection head are impacted,
Detecting an electrical change caused by the droplets discharged from the nozzles of the liquid discharge head landing on the landing surface, and detecting the presence or absence of the droplet discharge;
It has a wiping member for wiping and cleaning the landing surface of the landing member;
A waste liquid receiving portion for receiving the waste liquid of the liquid droplets is provided at least 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 a defect due to the accumulation of the waste liquid around the impacting member.

FIG. 1 is a plan view of a mechanical portion of an example of an image forming apparatus to which the present invention is applied. FIG. 5 is a block diagram for explaining the outline of a control unit of the same device. It is an explanatory view provided for explanation of a 1st embodiment of the present invention. It is principal part perspective explanatory drawing similarly. FIG. It is perspective explanatory drawing of a discharge detection unit similarly. FIG. 7 is a perspective view of the wiper retractable cover of the cleaning unit. FIG. 14 is a perspective view for explaining the operation of the wiping operation in the embodiment. FIG. 10 is a perspective view for explaining the comparative example 1; FIG. 10 is a perspective view for explaining the comparative example 2; It is perspective explanatory drawing of the discharge detection unit in 2nd Embodiment of this invention. It is principal part front explanatory drawing used for description of 3rd Embodiment of this invention. It is a plane explanatory view which is provided for explanation of the relation of the width of the direction which intersects perpendicularly with the wiping direction of the electrode plate in an embodiment, a wiper member, and a waste fluid receptacle part. FIG. 16 is an explanatory diagram for describing a relationship between a length of a nozzle array of a print head and a length of an electrode plate in a fourth embodiment of the present invention. It is perspective explanatory drawing of the discharge detection unit in 5th Embodiment of this invention. It is perspective explanatory drawing of the discharge detection unit in 6th Embodiment of this invention. It is perspective explanatory drawing of the discharge detection unit in 7th Embodiment of this invention. It is perspective explanatory drawing of the discharge detection unit in 8th Embodiment of this invention. It is cross-sectional explanatory drawing which follows 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 cross-sectional explanatory drawing which follows the electrode plate longitudinal direction of the discharge detection unit in 11th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the attached 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 a plan view of the mechanical portion of the image forming apparatus.

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

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

  As a liquid discharge head constituting the recording head 4, for example, a thermal actuator using phase change due to film boiling of the liquid can be used using a piezoelectric actuator such as a piezoelectric element or an electrothermal conversion element such as a heating resistor. .

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

  The conveyance belt 12 is rotationally moved in the sub-scanning direction by the conveyance roller 13 being rotationally driven by the sub-scanning motor 16 via the timing belt 17 and the timing pulley 18. The transport belt 12 is charged (charged) by a charging roller (not shown) while rotating.

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

  The maintenance and 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 droplets not contributing to image formation. It is configured by a discharge receiver and the like.

  Further, outside the recording area between the conveyance belt 12 and the maintenance and recovery mechanism 20, the discharge detection unit 100 constituting the discharge detection means according to the present invention is disposed in an area which can face the recording head 4 There is.

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

  Further, an encoder scale 23 having a predetermined pattern formed thereon is disposed between the side plates along the main scanning direction of the carriage 3, and the carriage 3 has an encoder sensor 24 formed of a transmission type photosensor for reading the pattern of the encoder scale 23. It is provided. The encoder scale 23 and the encoder sensor 24 constitute a linear encoder (main scanning encoder) for detecting the movement of the carriage 3.

  In addition, a code wheel 25 is attached to the shaft of the conveyance roller 13, and an encoder sensor 26 formed of a transmission type photo sensor for detecting a pattern formed on the code wheel 25 is provided. The code wheel 25 and the encoder sensor 26 constitute a rotary encoder (sub scanning encoder) for detecting the movement amount and movement position of the conveyance 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 conveying belt 12 charged and attracted, and the sheet 10 is moved in the sub scanning direction by the circumferential movement of the conveying belt 12. It is transported.

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

  By receiving a recording end signal or a signal that the rear end of the sheet 10 has reached the recording area, the recording operation is ended, and the sheet 10 is discharged to a discharge tray (not shown).

  Next, an outline of a control unit of the image forming apparatus will be described with reference to FIG. The same figure is a block diagram of the whole control part.

  The control unit 500 includes a main control unit 500A including a CPU 501 for controlling the entire apparatus, a ROM 502 for storing fixed data and programs executed by the CPU 501, and a RAM 503 for temporarily storing image data and the like. There is.

  The control unit 500 also controls a host I / F 506 that transfers data to and from 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. Is equipped. The encoder analysis unit 512 receives and analyzes detection signals from the main scanning encoder sensor 24 and the sub scanning encoder sensor 26.

Further, the control unit 500 controls the main scanning motor drive unit 513 for driving the main scanning motor 5, the sub scanning motor driving unit 514 for driving the sub scanning motor 16, and the I / O 516 between various sensors and actuators 517. Also has.
Is equipped.

  The control unit 500 also includes a discharge detection unit 531 that measures (detects) an electrical change when a droplet lands on the electrode plate 101 of the discharge detection unit 100 and determines discharge / non-discharge. Further, 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 is a data generation unit that generates print data, a drive waveform generation unit that generates a drive waveform for driving and controlling the recording head 4, and a head control signal for selecting a required drive signal from the drive waveform. And data transfer means for transferring print data. The drive waveform, head control signal, print data, etc. are output to the 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. The droplets are discharged according to the data.

  The encoder analysis unit 512 also 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 driving and controlling the main scanning motor 5 via the main scanning motor driving unit 513 based on the analysis result from the encoder analysis unit 512. Further, by controlling the driving of the sub scanning motor 16 via the sub scanning motor driving unit 514, the sheet 10 is controlled to be fed.

  When the droplet discharge detection of the recording head 4 is performed, the main control unit 500A of the control unit 500 moves the recording head 4 and causes droplet discharge from a required nozzle of the recording head 4 to be detected by the discharge detection unit 531. Control is performed to determine the droplet discharge state according to a signal.

  Next, a first embodiment of the present invention will be described with reference to FIGS. 3 to 7. FIG. 3 is an explanatory diagram for explaining the embodiment, FIG. 4 is a perspective explanatory view of the same parts, FIG. 5 is a front explanatory view of the same, FIG. 6 is a perspective explanatory view of the discharge detection unit, and FIG. It is a perspective explanatory view provided to the explanation of a retreat cover.

  The discharge detection unit 100 has a box-shaped holder member 103, and an electrode holding portion 104 which 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 disposed on the upper surface of the electrode holding portion 104 which can face the nozzle surface 41 of the recording head 4. The surface (facing surface) of the electrode plate 101 is a landing surface for discharge detection.

  The holder member 103 is formed of, for example, an insulating material such as plastic.

  The electrode plate 101 is a conductive metal plate, and is preferably formed of a material that is resistant to rusting and that does not easily deteriorate with respect to the ink. The electrode plate 101 can be formed of, for example, SUS 304, a copper alloy plated with Ni, or a plated Pd. Further, it is preferable to subject the surface of the electrode plate 101 on which the droplets are landed to a water repelling treatment.

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

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

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

  A waste fluid tube 112 is connected to the holder member 103. The waste fluid tube 112 forms a flow path leading from the lower side of the waste fluid receiving portion 110 to a waste fluid tank (not shown). Then, 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 portion 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 means including a wiper member 202 which is a wiping member for wiping the liquid droplets adhering to the surface (landing surface) of the electrode plate 101.

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

  The wiper member 202 is attached to a timing belt 223 wound around a driving pulley 221 and a driven pulley 222. The wiper member 202 and the timing belt 223 rotate in the direction of arrow A in FIG. 3 by rotationally driving the drive pulley 221 via the worm gear 224 and the gear 225 by the drive motor 203 which is a drive source attached to the carriage 3. Moving.

  In addition, a wiper retractable cover 204 is provided to cover the wiper member 202 at the retracted position. When the wiper member 202 is not used, the wiper member 202 is stored in the wiper retraction cover 204. Thus, it is possible to prevent a small amount of waste liquid adhering to the wiper member 202 from being scattered during the operation of the carriage.

  As shown in FIG. 7, the wiper retractable cover 204 becomes a waste liquid receiving portion 204a for receiving waste liquid falling from the wiper member 202, and the waste liquid receiving portion 204a is provided with an absorbing member 207 for absorbing and holding waste liquid. There is.

  The operation related to the wiping operation in this embodiment configured in this way will be described with reference to FIG. FIG. 8 is a perspective view for explaining the same.

  In the discharge detection operation, although the details will be described later, the presence or absence of droplet discharge is detected by an electrical change when droplets are discharged onto the electrode plate 101 one by one.

  Since the droplets 120 are left 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 member 202 in the nozzle arrangement direction to wipe the droplets 120 and clean them. Operation).

  At this time, the waste liquid 300 of the droplets transferred to the wiper member 202 may drip from the end of the wiper member 202 in the width direction (direction intersecting with the wiping direction). Not be dropped into the device. In addition, the waste liquid receiving portion 110 prevents the toner from being redeposited and retransferred to the wiper member 202 or coming into contact with the nozzle surface 41.

  Here, the problem regarding the wiping operation in the comparative example will be described with reference to FIGS. 9 and 10. FIG. 9 is a perspective view for explaining the comparative example 1, and FIG. 10 is a perspective view for explaining the comparative example 2. The parts corresponding to the present embodiment are denoted by the same reference numerals to simplify the description.

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

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

  Further, the waste liquid transferred from the wiper member 202 may be attached 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 retransfers to the wiper member 202 to lower the wiping performance, or contacts the nozzle surface of the recording head 4 to break the meniscus or the like to cause 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 midway in the longitudinal direction (wiping direction) of the electrode plate 101.

  Also in this configuration, the waste liquid transferred from the wiper member 202 adheres to the rib 1111 and becomes a deposit 301. Therefore, the transfer to the wiper member 202 is performed again and the wiping performance is lowered, or the contact with the nozzle surface of the recording head 4 is caused to destroy the meniscus or the like to cause the ejection failure.

  On the other hand, in the present embodiment, in particular, the electrode plate 101 is held by the island-shaped electrode holding portion 104 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 the problems as in 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 supply 701 that applies a high voltage VE (for example, 750 V) to the electrode plate 101. The high voltage power supply 701 is on / off controlled by the main control unit 500A.

  Further, a band pass filter (BPF) 702 for inputting a signal accompanying an electrical change when a droplet lands on the electrode plate 101, an amplifier (AMP) 703 for amplifying the signal, and A / D conversion of the amplified signal And an AD converter (ADC) 704. The conversion result of the ADC 704 is input to the main control unit 500A.

  Then, when the ejection detection is performed, the nozzle surface 41 of the recording head 4 and the electrode plate 101 are opposed to each other, the 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 one nozzle at a time.

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

  Therefore, the variation (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 control unit 500A as a measurement result (detection result).

  The main control unit 500A determines whether or not the measurement result (the fluctuation part) exceeds the preset threshold value, and when the measurement result exceeds the threshold value, it determines that discharge is occurring, and the threshold value is exceeded. When there is no discharge, it is determined that there is no discharge.

  In the present embodiment, since one nozzle is discharged to land on the electrode plate 101, it takes about 0.5 to 10 msec to determine whether one nozzle is discharged or not. After the discharge / non-discharge determination for all the 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 view of the discharge detection unit in the embodiment.

  In the present embodiment, a guide portion 104 a which 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. It is formed.

  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 (it may be inside).

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

  Next, a third embodiment of the present invention will be described with reference to FIG. 12 and FIG. FIG. 12 is a front view showing the main part of the embodiment, and FIG. 13 is a plan view showing the width of the electrode plate, the wiper member and the waste liquid receiving portion in the direction orthogonal to the wiping direction.

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

  Thus, the entire surface (landing surface) of the electrode plate 101 can be wiped off, and the waste liquid hanging down from both ends of the wiper member 202 can be reliably received by the waste liquid receiving portion 110.

  The wiper member 202 does not have to be disposed in a posture orthogonal to the wiping direction, and as shown in FIG. 13, can be disposed inclined in the wiping direction. Even in this case, the width W1 is a width in the 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 view of the relationship between the length of the nozzle array of the recording head and the length of the electrode plate in the same embodiment.

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

  Thus, droplet discharge detection can be performed for all the nozzles without moving the recording head 4 or the electrode plate 101.

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

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

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

  In addition, in the case where materials of different types of landing surfaces are formed, a gap or a step is generated on the boundary surface due to a problem of dimensional accuracy of parts or a difference in thermal contraction rate, and waste liquid tends to be deposited. On the other hand, when the entire landing surface is made into an electrode surface of a single member, there is no such gap or level difference, and no accumulation of waste liquid occurs.

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

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

  As a result, 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-angled or right-angled shape with a pointed tip, the wiper member 202 may be damaged, so it has a small radiused shape that can exhibit the scraping function.

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

  In the present embodiment, the curved surface shaped portion 115 is provided on the wiping start side by the wiper member 202. Here, the curved surface shaped 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) which may occur in the case of the 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 a perspective view of the discharge detection unit in the embodiment.

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

  As described above, when the landing surface and the curved surface shape portion are all formed by a single electrode member, the joint is eliminated, and it is possible to prevent the accumulation of waste liquid and the damage of the wiper member caused by the joint.

  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 electrode plate longitudinal direction (the wiping direction) of the discharge detection unit according to the embodiment.

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

  The one end 400 a of the electrode plate 101 is held by the electrode holding portion 104 by the stepped screw member 401 and the nut 402. In addition, the one end part 400a and the other end part 400b of the electrode plate 101 are parts which do not form an impact surface.

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

  In addition, a seal member 403 such as an O-ring is provided in a portion where the stepped screw member 401 penetrates the electrode holding portion 104 to prevent the movement of the liquid to the lead wire 102 side.

  Here, the other end 400 b of the electrode plate 101 is inserted into the hooking portion 404 provided on the electrode holding portion 104 of the holder member 103 for positioning and holding.

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

As described above, since the landing member is fixed to and held by the screw member by the screw member, 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 made while holding the landing member.

  Further, as in the present embodiment, by sealing the space between the screw member and the holder member with the seal member, in particular, when the surface of the impacting member is wiped by the wiping member for cleaning, the liquid acts as the impacting member Leakage to the outside through the screw member serving as a connection portion with the wiring member can be prevented, and deterioration of the wiring member (rust, tearing of the coating, etc.) can be prevented, and the life of the device can be extended.

  In addition, when the landing member is held by the holder member at two places, the number of screw members is fixed by fixing the one end side with the screw member and hooking (engaging with) the other end side to the hook portion. Thus, it is possible to reduce the number of screw tightening steps and the cost of parts of the screw member.

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

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

  As a result, when the stepped screw member 401 is tightened, the rotation of the nut 402 is restricted, so 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 electrode plate longitudinal direction (the wiping direction) of the discharge detection unit in the embodiment.

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

  The one end 400 a and the other end 400 b 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 fixing points, and as a result, the electrode plate 101 adheres closely to the holder member 103. This makes it possible to stabilize the shape of the electrode plate.

  Note that one screw member 406 penetrates the holder member 103 and is connected to the round terminal 102 a of the lead wire 102 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 impacting member is described as an example of an electrode plate, but the impacting member is a resistor (resistance member), and discharge detection is performed by detecting a change in resistance between both ends due to droplet impact. The same applies to what is done.

  In the present application, the term "paper" does not limit the material to paper, but includes OHP, cloth, glass, a substrate, etc., and means recording to which ink droplets, other liquids, etc. can be attached. Recording media, recording paper, recording paper and the like. Also, image formation, recording, printing, printing, and printing are all synonymous.

  Further, “image forming apparatus” means an apparatus for forming an image by discharging a liquid to a medium such as paper, yarn, fiber, fabric, leather, metal, plastic, glass, wood, and ceramic. Moreover, “image formation” is not only applying an image having meaning such as characters and figures to a medium, but also applying an image having no meaning such as a pattern to a medium (simply, a droplet is used as a medium). It also means to land on

  Further, “ink” is not limited to what is called ink unless particularly limited, and all liquids that can form an image, such as those called recording liquid, fixing processing liquid, liquid etc. Used as a generic term. For example, DNA samples, resists, pattern materials, resins and the like are also included.

  Further, the “image” is not limited to a flat one, and includes an image given to a three-dimensionally formed one and an image formed by three-dimensionally shaping a solid itself.

Reference Signs List 3 carriage 4, 4a, 4b recording head 41 nozzle surface 100 discharge detection unit 101 electrode plate (electrode member)
103 holder member 104 electrode holding portion 110 waste liquid receiving portion 200 cleaning unit 202 wiper member (dipping member)

Claims (13)

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 is
It has an impacting member which is disposed in an area that can face the liquid ejection head, and has an impacting surface on which the droplets ejected from the nozzle of the liquid ejection head are impacted,
Detecting an electrical change caused by the droplets discharged from the nozzles of the liquid discharge head landing on the landing surface, and detecting the presence or absence of the droplet discharge;
A wiping member that wipes and cleans the landing surface of the landing member;
A wiper cleaner for removing the waste liquid adhering to the wiping member;
There is provided a waste liquid receiving portion which is disposed at a distance from the landing surface at least on both sides of the landing surface in the direction orthogonal to the moving direction of the wiping member, and receives the waste liquid of the droplets.
The wiper cleaner is disposed on an outer wall portion located downstream of the waste liquid receiving portion in the moving direction of the wiping member, and a part of the wiper cleaner is positioned above the landing surface. An image forming apparatus characterized by A waste fluid channel for discharging the waste fluid;
The said waste-liquid flow path is arrange | positioned in the movement direction of the said wiping member among the bottoms of the said waste-liquid receiving part in the part between the said impact member and the said wiper cleaner in the moving direction of the said wiping member. Image forming apparatus. The image forming apparatus according to claim 1, wherein the waste liquid receiving portion is provided over the entire circumference of the landing surface. The impact member is an electrode member,
A potential difference is applied between the nozzle surface of the liquid discharge head and the landing surface, and electrical changes generated when droplets discharged from the nozzles of the liquid discharge head land on the landing surface are detected. The image forming apparatus according to any one of claims 1 to 3, wherein presence or absence of the droplet discharge is detected. The impact member is a resistance member,
4. The apparatus according to any one of claims 1 to 3, wherein the presence or absence of the droplet discharge is detected by detecting a change in resistance generated when droplets discharged from a nozzle of the liquid discharge head land on the landing surface. Image forming apparatus described. The width of the wiping member in the direction orthogonal to the moving direction is W1,
The width of the landing surface in the direction orthogonal to the moving direction of the wiping member is W2,
Assuming that the width of the waste fluid receiving portion in the direction orthogonal to the moving direction of the wiping member is W3,
W2 <W1 <W3
The image forming apparatus according to any one of claims 1 to 5, which is related to The image forming apparatus according to any one of claims 1 to 6, 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 any one of claims 1 to 7, wherein an angle formed by the side surface of the wiping start side by the wiping member and the landing surface is a right angle or an acute angle. The image forming apparatus according to any one of claims 1 to 8, wherein a curved surface portion is formed on the wiping start side by the wiping member. The image forming apparatus according to claim 9, wherein the landing surface and the curved surface portion are formed of the same member. A discharge detection unit for detecting the presence or absence of droplet discharge from a liquid discharge head, comprising:
It has an impacting member which is disposed in an area that can face the liquid ejection head, and has an impacting surface on which the droplets ejected from the nozzle of the liquid ejection head are impacted,
Detecting an electrical change caused by the droplets discharged from the nozzles of the liquid discharge head landing on the landing surface, and detecting the presence or absence of the droplet discharge;
A wiping member that wipes and cleans the landing surface of the landing member;
A wiper cleaner for removing the waste liquid adhering to the wiping member;
A waste liquid receiving portion is provided at least on both sides of the landing surface in a direction orthogonal to the moving direction of the wiping member, spaced from the landing surface, and receiving waste liquid from the droplets.
The wiper cleaner is disposed on an outer wall portion located downstream of the waste liquid receiving portion in the moving direction of the wiping member, and a part of the wiper cleaner is positioned above the landing surface. Discharge detection unit. A discharge detection unit for detecting the presence or absence of droplet discharge from a liquid discharge head, comprising:
It has an impacting member which is disposed in an area that can face the liquid ejection head, and has an impacting surface on which the droplets ejected from the nozzle of the liquid ejection head are impacted,
The electrical change caused by the droplet discharged from the nozzle of the liquid discharge head landing on the landing surface is detected, and the presence or absence of the droplet discharge is detected.
A holder member for holding the impact member;
At least one end of the impacting member is held by the holder member by a screw member,
The screw member penetrates the holder member and is electrically connected to the wiring member outside the holder member.
A discharge detection unit characterized in that the impact member and the wiring member are electrically connected via the screw member. A liquid discharge head that discharges droplets;
A discharge detection unit that detects the presence or absence of droplet discharge from the liquid discharge head;
A liquid discharge device having
The discharge detection unit is
It has an impacting member which is disposed in an area that can face the liquid ejection head, and has an impacting surface on which the droplets ejected from the nozzle of the liquid ejection head are impacted,
Detecting an electrical change caused by the droplets discharged from the nozzles of the liquid discharge head landing on the landing surface, and detecting the presence or absence of the droplet discharge;
A wiping member that wipes and cleans the landing surface of the landing member;
A wiper cleaner for removing the waste liquid adhering to the wiping member;
A waste liquid receiving portion is provided at least on both sides of the landing surface in a direction orthogonal to the moving direction of the wiping member, spaced from the landing surface, and receiving waste liquid from the droplets.
The wiper cleaner is disposed on an outer wall portion located downstream of the waste liquid receiving portion in the moving direction of the wiping member, and a part of the wiper cleaner is positioned above the landing surface. Liquid discharge device.

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