JP2014097642A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problems: waste liquid adheres to a wiping member, which wipes droplets for detecting droplet ejection adhered to an electrode plate, and to a cleaning member provided for cleaning the wiping member, may be solidified, and the wiping performance may decrease.SOLUTION: An ejection detecting unit 100, having an electrode plate 101 arranged outside a recording area, detects electric changes of the electrode plate 101 generated when the droplets ejected from the nozzles of a recording head 4 land on the electrode plate 101, while a potential difference between a nozzle face 41 of the recording head 4 and the electrode plate 101 is given with the nozzle face 41 of the recording head 4 opposed to the electrode plate 101, and detects ejection or non-ejection of droplets. A cleaning unit 200 includes a wiping member 202 for wiping the electrode plate 101. The wiping member 202 and the electrode plate 101 are relatively moved in parallel to a nozzle array direction to wipe the electrode plate 101.

Description

  The present invention relates to an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, 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 of a liquid discharge recording method using a recording head for discharging ink droplets. .

  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. There is what I did.

  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

  In the case where the presence or absence of discharge is detected by discharging a droplet onto the electrode plate as described above and reading an electrical change, the droplet adheres to the electrode plate as the discharge is detected. Here, the droplets ejected from each nozzle of the recording head for ejection detection are droplets having a minute droplet amount.

  Therefore, as disclosed in Patent Document 2, even if the wiping member is wiped in the same direction as the carriage movement direction, that is, the direction perpendicular to the nozzle arrangement direction of the recording head, the droplets on the electrode plate do not collect. , It adheres to a wiping member for every drop.

  As a result, the waste liquid of the liquid adhering to the wiping member is solidified, the wiping performance of the wiping member deteriorates with time, the electrode plate cannot be cleaned, and the discharge detection with high accuracy cannot be performed. There is.

  This invention is made | formed in view of said subject, and it aims at suppressing deterioration with time of the wiping performance of a wiping member.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A recording head having a plurality of nozzles for discharging droplets;
Discharge detection means for detecting the presence or absence of droplet discharge from the recording head, and
The discharge detection means includes
An electrode member disposed in a region facing the recording head and having droplets ejected from nozzles of the recording head landed;
A liquid droplet discharged from the nozzle of the recording head is applied to the electrode in a state where a potential difference is applied between the nozzle surface of the recording head and the electrode member, and the nozzle surface of the recording head is opposed to the electrode member. Detecting the electrical change of the electrode member that occurs when landing on the member, detecting the presence or absence of the droplet discharge,
A cleaning means for cleaning the electrode member of the discharge detection means;
The cleaning means includes
Having a wiping member for wiping the droplets adhering to the electrode member;
The wiping member and the electrode member are relatively moved in a direction parallel to the nozzle arrangement direction to clean the electrode member.

  According to the present invention, deterioration over time of the wiping performance of the wiping member can be suppressed.

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 explanatory drawing with which it uses for description of the recording head of the apparatus. It is block explanatory drawing with which the outline | summary of the control part of the apparatus is provided. FIG. 3 is an explanatory diagram including a carriage part, a side surface of a discharge detection unit, and a block circuit of a discharge detection unit for explaining the first embodiment of the present invention. FIG. 4 is a perspective view of the main part of the carriage part and the discharge detection unit. It is front explanatory drawing similarly. It is a perspective explanatory view of a discharge detection unit. It is an isometric view explanatory drawing used for description of a wiper evacuation cover. FIG. 5 is a perspective explanatory view for explaining the relationship among the sizes of ejection detection droplets, electrode plates, wiper members, openings, and wiper cleaners. It is a flowchart with which it uses for description of an example of discharge detection control and cleaning control by a control part. It is front explanatory drawing similarly. It is also a proof explanatory drawing. It is a perspective explanatory view similarly. It is a perspective explanatory view similarly. It is a perspective explanatory view similarly. It is a perspective explanatory view similarly. It is a perspective explanatory view similarly. It is a perspective explanatory view similarly. It is plane explanatory drawing with which it uses for description of the wiping direction (wiping direction) by the wiper member in a comparative example. It is front explanatory drawing similarly. It is front explanatory drawing similarly. It is plane explanatory drawing with which it uses for description of the wiping direction in this embodiment. It is a side explanatory view similarly. It is an isometric view explanatory drawing used for description of 2nd Embodiment of this invention. It is perspective explanatory drawing with which it uses for description of 3rd 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 to which the present invention is applied 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.

  As shown in FIG. 2, the recording head 4 has two nozzle rows Na and Nb in which a plurality of nozzles 4n are arranged. One nozzle row Na of the recording head 4a discharges black (K) droplets, and the other nozzle row Nb discharges cyan (C) droplets. One nozzle row Na of the recording head 4b discharges magenta (M) droplets, and the other nozzle row Nb 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 for cleaning an electrode plate 101 (described later) of the discharge detection unit 100.

  Further, an encoder scale 23 having a predetermined pattern is stretched between both side plates along the main scanning direction of the carriage 3, and the encoder sensor 24 is formed of a transmission type photosensor that reads the pattern of the encoder scale 23 on the carriage 3. Is 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.

The control unit 500 also includes a main scanning motor driving unit 113 that drives the main scanning motor 5, a sub scanning motor driving unit 114 that drives the sub scanning motor 16, and an I / O 516 between various sensors and actuators 517. It also has.
It has.

  In addition, the control unit 500 includes a discharge detection unit 521 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 522 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.

  The main control unit 500A of the control unit 500 moves the recording head 4 to perform droplet ejection from a required nozzle of the recording head 4 when performing droplet ejection detection of the recording head 4. Control is performed to determine the droplet discharge state based on the detection signal.

  Next, a first embodiment of the present invention will be described with reference to FIGS. FIG. 4 is an explanatory view including a carriage part and a side surface of the discharge detection unit and a block circuit of the discharge detection unit, and FIG. 5 is a perspective view of a principal part of the carriage part and the discharge detection unit, and FIG. It is front explanatory drawing similarly.

  In the discharge detection unit 100, an electrode plate 101, which is an electrode member, is disposed on the upper surface of the holder member 103 that can face the nozzle surface 41 of the recording head 4.

  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 is electrically connected to the electrode plate 101 and is connected to a discharge detection unit 531 described later in detail.

  Further, as shown in FIG. 7, the holder member 103 has an opening 110 formed on the end side in the wiping direction of the wiper member 202. Then, a wiper cleaner 111 which is a cleaning member for removing and cleaning waste liquid (droplets adhering to the wiper member 202) from the wiper member 202 is formed at a part (edge portion) of the opening 110. ing.

  The holder member 103 is provided with a waste liquid tube 112 that forms a flow path from the lower side of the opening 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 discharges the waste liquid accumulated at the bottom of the opening 110 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 for wiping off droplets attached to the 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 made 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 together 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. 8, 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.

  Here, the relationship among the sizes of the discharge detection droplet, the electrode plate, the wiper member, the opening, and the wiper cleaner will be described with reference to FIG. FIG. 9 is an explanatory diagram for explaining the same.

  The width L1 of the electrode plate 101 (the width in the direction orthogonal to the nozzle arrangement direction; the same applies hereinafter) L1 is larger than the diameter D of the discharge detection droplet (D <L1). In this case, it is preferable that the width L1 of the electrode plate 101 be sufficiently larger than the diameter D of the droplets in consideration of the droplet landing position accuracy, the carriage 3 stop position accuracy, the component accuracy, and the like.

  In the present embodiment, the two nozzle rows Na and Nb of the recording head 4 perform detection and ejection at the same carriage stop position, so the width L1 of the electrode plate 101 is (droplet diameter D + nozzle). The distance between the row Na and the nozzle row Nb).

  The width L2 of the wiper member 202 is wider than the width L1 of the electrode plate 101 (L1 <L2). Thereby, the wiping residue of the electrode plate 101 can be reduced.

  The width L3 of the wiper cleaner 111 is wider than the width L2 of the wiper member 202 (L2 <L3). Thereby, the waste liquid adhering to the wiper member 202 can be reliably scraped off and cleaned.

  The width L4 of the opening 110 is wider than the width L2 of the wiper member 202 (L2 <L4). Thereby, the whole area of the wiper member 202 in the width direction can be accommodated in the opening 110, and scattering of waste liquid can be prevented.

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

  As shown in FIG. 4, the discharge detection unit 231 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, an example of discharge detection control and cleaning control by the control unit will be described with reference to the flowchart of FIG. In addition, reference will also be made to the illustrations of FIGS.

  First, as shown in FIG. 11, the carriage 3 is moved to a position where the nozzle surface 41 of the recording head 4 a faces the electrode plate 101. Then, ejection detection is performed by ejecting droplets for ejection detection from the nozzle array Na of the recording head 4a, and then ejection detection is performed by ejecting liquid droplets for ejection detection from the nozzle array Nb of the recording head 4a. To do.

  Thereafter, as shown in FIG. 12, the carriage 3 is moved to a position where the nozzle surface 41 of the recording head 4 b faces the electrode plate 101. Then, ejection detection is performed by ejecting droplets for ejection detection from the nozzle array Na of the recording head 4b, and then ejection detection is performed by ejecting liquid droplets for ejection detection from the nozzle array Nb of the recording head 4b. To do.

  After the discharge detection, as shown in FIG. 6, the carriage 3 is moved to a cleaning position (wiping enable position) where the cleaning unit 200 faces the electrode plate 101.

  Then, the wiper member 202 in the retracted position as shown in FIG. 5 is moved at a speed V1 (in the direction of arrow A in FIG. 4) by driving the motor 203 as shown in FIGS. The member 202 wipes the surface of the electrode plate 101. At this time, the moving speed V1 of the wiper member 202 is, for example, about 50 to 200 mm / sec.

  Here, as shown in FIG. 15, the movement speed of the wiper member 202 is reduced to a speed V2 (V2 <V1) in the vicinity where the wiper member 202 wipes the electrode plate 101. This prevents the waste liquid adhering to the wiper member 202 from scattering. The moving speed V2 of the wiper member 202 at this time is set to 20 to 80% of the moving speed V1, for example.

  Thereafter, as shown in FIGS. 16 and 17, the wiper member 202 comes into contact with the wiper cleaner 111 and scrapes off the adhering waste liquid.

  As shown in FIG. 18, when the wiper member 202 passes through the wiper cleaner 111, the moving speed of the wiper member 202 is returned to the speed V1. Thereby, the wiper member 202 can be quickly returned to the retracted position.

  Thereafter, when the wiper member 202 returns to the retracted position covered with the wiper retracting cover 204, the drive motor 203 is stopped and the wiper member 202 is stopped.

  Thereafter, the suction pump (not shown) is driven to suck and discharge the waste liquid collected and accommodated in the opening 110 into a waste liquid tank (not shown).

  In this embodiment, the electrode plate 101 is wiped after all the nozzles Na and Nb of all the recording heads 4a and 4b have been detected for ejection, but one recording is performed. You may make it perform discharge detection and wiping for every head.

  However, the amount of ink adhering to the electrode plate with one head is usually small and difficult to clean (ink is difficult to collect into the waste liquid tank). The waste liquid can be collected more efficiently by performing the electrode cleaning after the detection.

  Next, the wiping direction (wiping direction) by the wiper member will be described with reference to FIGS. 19 to 21 are explanatory diagrams for explaining the wiping direction of the comparative example, and FIGS. 22 and 23 are explanatory diagrams for explaining the wiping direction of the present embodiment.

  First, in the comparative example shown in FIGS. 19 and 20, the wiper member 1202 and the wiper cleaner 1111 are formed with the longitudinal direction as the nozzle arrangement direction.

  Then, as shown in each figure (a), a droplet 800 for ejection detection is ejected onto the electrode plate 101. Thereafter, as shown in each figure (b), the wiper member 1202 is moved in the wiping direction orthogonal to the nozzle arrangement direction, and the droplet 800 on the electrode plate 1101 is wiped off. The wiper member 1202 further moves as shown in each figure (c), and the waste liquid 801 adhering to the wiper member 1202 is scraped off by the wiper cleaner 1111.

  At this time, the droplet 800 is a very small droplet amount, and since the wiping is performed in a direction orthogonal to the nozzle arrangement direction, the droplets 800 on the electrode plate 101 are not collected. Therefore, the waste liquid 801 is dispersed and adhered to the edge portion of the wiper cleaner 1111 in a line shape.

  As a result, the waste liquid 801 adhering to the edge portion of the wiper cleaner 1111 does not fall by its own weight, does not move even if it is forcibly sucked, and is fixed on the spot.

  When the next discharge detection operation is performed in a state where the waste liquid 801 is fixed in this manner, similarly, the new waste liquid is adhered and fixed so as to cover the already fixed waste liquid 801.

  When the waste liquid fixed to the edge portion of the wiper cleaner 1111 accumulates and grows in this way, it interferes with the nozzle surface 41 of the recording head 4 and the meniscus of the nozzle surface 41 of the recording head 4 is destroyed as shown in FIG. For example, stable droplet discharge cannot be performed.

  On the other hand, in the present embodiment, as shown in FIGS. 22A and 23A, a droplet 800 for ejection detection is ejected onto the electrode plate 101. FIG. Thereafter, as shown in each figure (b), the wiper member 202 is moved in the nozzle arrangement direction to wipe the droplets 800 on the electrode plate 1101. The wiper member 202 further moves as shown in each figure (c), and the waste liquid 801 adhering to the wiper member 202 is scraped off by the wiper cleaner 111.

  In this way, by moving the wiper member 202 in the nozzle arrangement direction and wiping the droplets 800 on the electrode plate 1101, the waste liquid 801 adhering to the wiper cleaner 111 is at one location as shown in each figure (c). It is gathered up.

  As a result, the waste liquid 801 adhering to the edge portion of the wiper cleaner 111 can fall by its own weight, and sticking and accumulation on the edge portion of the wiper cleaner 111 is reduced. As a result, by performing suction, the waste liquid can be easily discharged to the waste liquid tank.

  As described above, by cleaning the electrode member by relatively moving the wiping member and the electrode member in the direction parallel to the nozzle arrangement direction, the waste liquid in the cleaning member for cleaning the wiping member and the wiping member can be obtained. Adherence and growth are reduced, and deterioration over time of the wiping performance of the wiping member can be suppressed. Thereby, when performing droplet discharge detection, it becomes possible to perform discharge detection with high accuracy.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 24 is an explanatory perspective view for explaining the embodiment.

  In the present embodiment, the drive motor 203 as a drive source for moving the wiper member 202 is mounted on the carriage 3 in the first embodiment, whereas the drive motor 263 as a drive source is disposed on the apparatus main body side. ing.

  That is, the drive motor 263 is attached to the support member 261 provided on the apparatus main body side. The idler gear 262 rotatably supported by the support member 261 is rotated through the worm gear 266 and the gear 267 rotated by the drive motor 263.

  The idler gear 262 meshes with an idler gear 264 rotatably held on the carriage 3 side so as to be connected and disconnected. The idler gear 264 on the carriage 3 side meshes with the gear 265 of the drive pulley 221.

  When performing the wiping operation of the electrode plate 101, the wiper member 202 is moved by driving the drive motor 263 by moving the carriage 3 to the wiping position so that the idler gear 262 and the idler gear 264 mesh with each other. The plate 101 is wiped away.

  Thus, by arranging the drive motor for moving the wiper member on the apparatus main body side, the weight of the carriage can be reduced.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 25 is an explanatory perspective view for explaining the embodiment.

  In this embodiment, wiping is performed by moving the electrode plate side with respect to the wiper member.

  That is, the discharge detection unit 100 is disposed so as to be able to reciprocate in the nozzle arrangement direction (arrow B direction and arrow C direction). The discharge detection unit 100 is moved by a drive motor 273 through a pinion 271 and a rack 272 provided on the holder member 103 side.

  On the other hand, the wiper member 270 is provided on the carriage 3 so as to be rotatable in the arrow D direction. The wiper member 270 is provided with a waste liquid receiving member 274. Although not shown, the waste liquid receiving member 274 is provided with an absorbing member.

  When performing the wiping operation of the electrode plate 101, the ejection detection unit 100 is moved in the arrow B direction so that the wiping start position of the electrode plate 101 is opposed to the wiper member 270, and the wiper member 270 is moved in the arrow D direction. Rotate. As a result, the wiper member 270 hits and contacts the surface of the electrode plate 101.

  From this state, the electrode plate 101 is wiped by the wiper member 270 by moving the discharge detection unit 100 in the direction of arrow C. After wiping, the wiper member 270 returns to the state shown in FIG.

  By configuring in this way, the weight of the carriage can be reduced as compared with the second embodiment. However, since an actuator for rotating the wiper member and a mechanism for moving the discharge detection unit are required, the number of actuators is larger than that in the first embodiment.

  In the above-described embodiment, the electrode plate (electrode member) is disposed outside the recording area (outside the paper conveyance area), but the present invention is not limited to this. For example, the electrode member can be disposed in the sheet conveyance area by adopting a configuration in which the sheet is conveyed by an arrangement, a conveyance roller, and a platen member having a rib in the recording area on the upstream side of the image forming unit.

  In the above-described embodiment, an example in which the present invention is applied to a serial type image forming apparatus has been described. However, the present invention can be similarly applied to a line type image forming apparatus.

  Further, in the above embodiment, the electrode member (electrode plate) is used as the discharge detection unit, but other than this, it is used as a blank discharge receiver (a member that receives a droplet (empty discharge droplet) that does not contribute to image formation). You can also.

  That is, a potential difference is applied between the nozzle surface of the recording head and the electrode member, and empty discharge droplets discharged from the nozzles of the recording head land on the electrode member with the nozzle surface of the recording head facing the electrode member. Let

  In this way, by generating a potential difference between the nozzle surface of the recording head and the electrode member and performing idle ejection, the occurrence of mist is reduced.

  Also in this case, a cleaning means for cleaning the electrode member is provided, the cleaning means has a wiping member for wiping off the droplets adhering to the electrode member, and the wiping member and the electrode member are relative to each other in a direction parallel to the nozzle arrangement direction. By moving the electrode member cleanly, the electrode member is cleaned, so that the deterioration of the wiping performance of the wiping member over time can be suppressed as in the above embodiment.

  The above-described droplet discharge detection operation can be controlled by a computer using a program stored in the ROM of the control unit. This program can be provided by being stored in a storage medium, or provided by downloading through a network such as the Internet.

  Further, in the present application, “paper” is not limited to paper, but includes OHP, cloth, glass, a substrate, etc., 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)
110 opening 111 wiper cleaner (cleaning member)
200 Cleaning unit 202 Wiper member (wiping member)

Claims (10)

A recording head having a plurality of nozzles for discharging droplets;
Discharge detection means for detecting the presence or absence of droplet discharge from the recording head, and
The discharge detection means includes
An electrode member disposed in a region facing the recording head and having droplets ejected from nozzles of the recording head landed;
A liquid droplet discharged from the nozzle of the recording head is applied to the electrode in a state where a potential difference is applied between the nozzle surface of the recording head and the electrode member, and the nozzle surface of the recording head is opposed to the electrode member. Detecting the electrical change of the electrode member that occurs when landing on the member, detecting the presence or absence of the droplet discharge,
A cleaning means for cleaning the electrode member of the discharge detection means;
The cleaning means includes
Having a wiping member for wiping the droplets adhering to the electrode member;
An image forming apparatus, wherein the electrode member is cleaned by relatively moving the wiping member and the electrode member in a direction parallel to a nozzle arrangement direction. On the terminal side of the wiping direction of the electrode member by the wiping member, a member having an opening for receiving waste liquid is disposed,
The image forming apparatus according to claim 1, wherein a cleaning member that removes waste liquid adhering to the wiping member of the cleaning unit is provided in the opening. A diameter D of droplets ejected from the recording head landed on the electrode member;
A width L1 in a direction perpendicular to the nozzle arrangement direction of the electrode members;
A width L2 in a direction orthogonal to the nozzle arrangement direction of the wiping member;
A width L3 in a direction orthogonal to the nozzle arrangement direction of the cleaning member,
D <L1 <L2 <L3
The image forming apparatus according to claim 1, wherein the image forming apparatus has a relationship of: A diameter D of droplets ejected from the recording head landed on the electrode member;
A width L1 in a direction perpendicular to the nozzle arrangement direction of the electrode members;
A width L2 in a direction orthogonal to the nozzle arrangement direction of the wiping member;
A width L4 in a direction orthogonal to the nozzle arrangement direction of the openings,
D <L1 <L2 <L4
The image forming apparatus according to claim 2, wherein: The said cleaning means has a waste liquid receiving member which receives the waste liquid which hangs down from the said wiping member when the said wiping member is in the retracted position retracted from the electrode member. Image forming apparatus. The recording head is mounted and has a carriage that is reciprocated;
The image forming apparatus according to claim 1, wherein the cleaning unit is mounted on the carriage.   The image forming apparatus according to claim 1, wherein a driving source for operating the wiping member of the cleaning unit is disposed on the apparatus main body side.   7. The image forming apparatus according to claim 1, further comprising means for moving the electrode member relative to the wiping member of the cleaning means.   The image forming apparatus according to claim 1, wherein the wiping member has a higher water repellency than the electrode member. A recording head having a plurality of nozzles for discharging droplets;
An electrode member on which droplets ejected from the nozzles of the recording head land,
A potential difference is applied between the nozzle surface of the recording head and the electrode member, and droplets ejected from the nozzles of the recording head in a state where the nozzle surface of the recording head is opposed to the electrode member. To land on the member,
A cleaning means for cleaning the electrode member;
The cleaning means includes
Having a wiping member for wiping the droplets adhering to the electrode member;
An image forming apparatus, wherein the electrode member is cleaned by relatively moving the wiping member and the electrode member in a direction parallel to a nozzle arrangement direction.

Images