JP5282585B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that idle ejection droplets do not go straight due to an air stream caused by the circumvolution of a conveyance belt and adhere on the wall surface of an idle ejection receiving part when idle ejection is carried out through an opening part of the conveyance belt, so that waste liquid substances are eccentrically accumulated in an idle ejection receiver. <P>SOLUTION: The idle ejection receiver 201, which is disposed so as to face a head module 51 for ejecting liquid droplets through the conveyance belt 43, is detachably mounted to a bracket 202, and held rotatably with respect to a rotating shaft 211. The idle ejection receiver 201 is disposed to tilt to the ejection direction of idle ejection droplets ejected from the head 101 of a head module 51 to an suction hole 46 or the opening part 47 of the conveyance belt 43, the idle ejection droplets not contributing to image formation, so that the bias of landing points is reduced by tilting the idle ejection receiver 201 when the flying direction of the idle ejection droplets slants. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus provided with a recording head for discharging droplets.

  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. . This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected onto a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

  In the present application, the “image forming apparatus” of the liquid discharge method is an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or the like. In addition, “image formation” means not only that an image having a meaning such as a character or a figure is imparted to the medium but also an image having no meaning such as a pattern is imparted to the medium (simply liquid. It also means that a droplet hits the medium). “Ink” is not limited to ink, but is used as a general term for all liquids capable of image formation, such as recording liquid, fixing processing liquid, and liquid. DNA samples, resists, pattern materials and the like are also included.

  In such an image forming apparatus (hereinafter, also simply referred to as “inkjet recording apparatus”), the recording head is caused by the evaporation of the solvent from the nozzle because of recording by discharging ink from the nozzle onto the paper. There is a problem in that a recording failure occurs due to a discharge failure due to an increase in ink viscosity, solidification of ink, adhesion of dust, and mixing of bubbles.

  For this reason, in order to maintain the ink droplet ejection state from the recording head satisfactorily, a so-called idle ejection operation (preliminary ejection operation) is performed in which droplets that do not contribute to image formation (empty ejection droplets) are ejected during a printing operation or the like. I am doing so.

  In the serial type image forming apparatus, since the recording is performed while moving the recording head, the position where the idle ejection is performed is set in an area outside the sheet conveying path by the conveying means for conveying the sheet, and the recording head reciprocates. Since idle ejection can be performed outside the transport path as a process of the operation, the interruption time of the printing operation is short, and there is almost no problem that the printing speed is lowered.

  On the other hand, in a line type image forming apparatus that forms an image without moving the recording head (fixed state), if an empty ejection position is set outside the paper conveyance path, the printing operation is interrupted. Since it is necessary to move the recording head to the idle ejection position outside the conveyance path, there is a problem that considerable time loss occurs and continuous printing and high-speed printing are not realized.

  Therefore, as described in Patent Documents 1 and 2, conventionally, in an opening such as a preliminary discharge hole provided in a conveyance belt that conveys easily or a plurality of air suction holes formed in the conveyance belt. It is known that ink is ejected idly toward the ink and is received by an ink receiving member arranged to face the recording head via a conveying belt.

JP 2006-159556 A JP 2007-168277 A

  However, in the prior art, an empty discharge receiver that receives empty discharged ink (empty discharge droplets) that has passed through an opening such as a suction hole of the transfer belt at a position opposite to the recording head on the back side of the transfer belt. The empty discharge droplets do not advance straight due to the air flow caused by the circular movement of the conveyor belt, but adhere to the wall surface of the empty discharge receiving portion, and the moisture etc. evaporates, resulting in thickening of the ink waste liquid. Therefore, when the full discharge detection of the empty discharge receiving part is detected, it overflows from the empty discharge receiving part, or conversely, if thick ink adheres to a part near the full detection, the empty discharge receiver is full. However, there are issues such as detecting fullness.

  In addition, when the paper is sucked onto the transport belt by air suction, if the idle discharge receiving portion is arranged in the suction transport belt, the empty discharge receiving portion interferes with the suction of the paper, and the suction force of the paper is reduced. Or the like, the paper floats up, a jam occurs, or the mist generated by the idle discharge cannot be sufficiently collected in the idle discharge receiving portion.

  The present invention has been made in view of the above problems, and an object of the present invention is to reliably collect empty discharged droplets by an empty discharge receiver.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A recording head for discharging droplets;
Conveying means for conveying a recording medium;
An empty discharge receiver that is disposed at a position facing the recording head via the conveying unit and receives empty discharged droplets that do not contribute to image formation discharged from the recording head toward the opening of the conveying unit. ,
The idle discharge receiver is arranged to be inclined with respect to the discharge direction of the empty discharge droplets from the recording head.

  Here, the idle discharge receptacle may be configured such that the inclination angle is changed according to the printing speed.

  Further, the idle discharge receiver may be provided with a leveling member for leveling the surface of the stored empty discharge droplets.

  According to the image forming apparatus of the present invention, since the empty discharge receiver is disposed so as to be tiltable with respect to the discharge direction of the empty discharge droplets, the empty discharge receiver is inclined and bent by the airflow caused by the movement of the conveying means. It is possible to reliably receive and collect the generated empty ejection droplets.

1 is a schematic configuration diagram illustrating an overall configuration illustrating an example of an image forming apparatus according to the present invention. It is a typical plane explanatory view of the device. It is explanatory drawing which shows an example of a head module. It is explanatory drawing which shows an example of a head. It is a plane explanatory view showing an example of a conveyance belt. It is a plane explanatory view showing other examples of a conveyance belt. It is a plane explanatory view showing the composition of the idle discharge receiving part concerning a 1st embodiment of the present invention. It is front explanatory drawing similarly. It is explanatory drawing with which it uses for description of the inclination angle adjustment of an empty discharge receptacle. It is explanatory drawing with which it uses for description of operation | movement of a leveling member. 2 is an explanatory block diagram illustrating an example of a control unit of the image forming apparatus. FIG. It is a flowchart with which it uses for description of angle adjustment control of the idle discharge receptacle by the same control part. It is typical front explanatory drawing of the conveyance unit part in 2nd Embodiment of this invention. It is a plane explanatory drawing similarly. It is typical front explanatory drawing of the conveyance unit part in 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 according to the present invention will be described with reference to FIGS. 1 is a schematic configuration diagram for explaining the overall configuration of the image forming apparatus, and FIG. 2 is a schematic plan explanatory diagram of the apparatus.

  This image forming apparatus is a line type image forming apparatus, and includes an apparatus main body 1, a paper feed tray 2 on which paper P is stacked and fed, a paper discharge tray 3 on which printed paper P is discharged and stacked, and paper P An image forming unit 5 that includes a head module 51 that constitutes a recording head that discharges and prints droplets on a sheet P that is transported by the transport unit 4. The head cleaning device 6 that is a maintenance / recovery mechanism that performs maintenance / recovery of each recording head of the image forming unit 5 after printing is completed or at a required timing, a conveyance guide portion 7 that opens and closes the head cleaning device 6, and the image forming unit 5 An ink tank unit 8 composed of sub-tanks that supply ink to the head module 51, and a main tank that supplies ink to the ink tank unit 8. And a tank unit 9.

  The apparatus main body 1 includes front and rear side plates and stays (not shown), and the sheets P stacked on the sheet feed tray 2 are fed one by one to the transport unit 4 by the separation roller 21 and the sheet feed roller 22. Is done.

  The transport unit 4 is disposed on the back surface side of the transport belt 43, a transport drive roller 41 </ b> A, a transport driven roller 41 </ b> B, a transport belt 43 as an endless transport means wound around these rollers 41 </ b> A and 41 </ b> B. A platen member (belt guide member) 45 is provided. As shown in FIG. 5 or 6, a plurality of suction holes 46 are formed on the surface of the transport belt 43, and a suction fan 44 that sucks the paper P is disposed below the transport belt 43. . Further, conveyance guide rollers 42A and 42B are respectively held on guides (not shown) on the conveyance driving roller 41A and conveyance driven roller 41B and are in contact with the belt 43 by their own weight.

  The conveyance belt 43 is rotated by the rotation of the conveyance drive roller 41 </ b> A by a motor (not shown), and the sheet P is sucked onto the conveyance belt 43 by the suction force generated by the suction fan 44. It is conveyed by movement. The transport driven roller 41 </ b> B and the transport guide rollers 42 </ b> A and 42 </ b> B rotate following the transport belt 43.

  An image forming unit 5 composed of a plurality of head modules 51 for discharging droplets to be printed on the paper P is disposed above the transport unit 4 so as to be movable in the arrow A direction (and the reverse direction). The image forming unit 5 is moved to above the cleaning device 6 during the maintenance and recovery operation (during cleaning), and is returned to the position shown in FIG. 1 during image formation.

  As shown in FIGS. 3 and 4, the image forming unit 5 arranges a plurality of heads 101 in which a plurality of nozzles 102 for ejecting liquid droplets are arranged in two rows on the nozzle surface 104, and ink is applied to each head 101. A head module 51A, 51B, 51C, 51D integrated with a distribution / branching member 54 is provided with a recording head unit 50 that is arranged and attached to a line base member 52 along the sheet conveyance direction.

  Here, one of the two nozzle rows of the head modules 51A and 51B ejects yellow (Y) droplets and the other of the magenta (M) droplets, and the two nozzle rows of the head modules 51C and 51D. On the other hand, cyan (C) droplets are discharged, and on the other hand, black (K) droplets are discharged. That is, in the image forming unit 5, two head modules 51 that discharge droplets of the same color are arranged side by side in the paper transport direction, and the two head modules 51 form a nozzle row corresponding to the paper width. It has a configuration.

  On the upstream side of the image forming unit 5, a sub tank (ink tank) 81 of the ink tank unit 8 (only one ink tank is indicated for convenience in the drawing) is disposed, and the sub tank is connected via a supply tube 82. Ink is supplied from 81 to the branching member 54 of each head module 51, and a negative pressure with respect to each head of the head module 51 is formed by a water head difference between the ink tank 81 and the head module 51. The ink tank unit 8 is arranged so as to be movable in the direction of arrow A together with the image forming unit 5. Note that the supply tube 82 from the ink tank 81 to the head module 51 is shown as being connected from above the head module 51 for easy understanding, but in reality, the longitudinal direction of the head module 51 (the direction orthogonal to the paper transport direction). ) Is connected to the end.

  Further, a main tank unit 9 serving as an ink storage unit is disposed on the upstream side of the ink tank 81, and ink is supplied from the main tank (ink cartridge) 91 to the sub tank 81 through the supply tube 92.

  On the downstream side of the transport unit 4, a transport guide portion 7 that discharges the paper P to the paper discharge tray 3 is provided. The paper P guided and conveyed by the conveyance guide unit 7 is discharged to the paper discharge tray 3. The paper discharge tray 3 includes a pair of side fences 31 that regulate the width direction of the paper P and an end fence 32 that regulates the front end of the paper P.

  The maintenance / recovery mechanism (head cleaning device) 6 includes four rows of cleaning units 61 </ b> A to 61 </ b> D corresponding to each head module 51 constituting the recording head unit 50 of the image forming unit 5, and one cleaning unit 61. The head module 51 includes a cap member 62 for capping the nozzle surface corresponding to each head 101 and a wiping member (wiper member) 64 for wiping the nozzle surface. The cap member 62 of each cleaning means 61 can be moved up and down independently for each row. Further, below the cleaning unit 61, suction pumps 63 </ b> A to 63 </ b> D, which are suction units for sucking ink from the nozzles with the cap member 62 capping the nozzle surface of the head 101, are arranged.

  Further, in this image forming apparatus, after the printing is finished, when the nozzle surface of each head of the head module 51 that discharges droplets is capped by the cleaning unit 61, or ink is sucked from the nozzle, or the head module 51 When the ink adhering to the nozzle surface of each head is cleaned with a wiping member, as shown in FIG. 1, after the printing is stopped, the entire transport unit 4 rotates in the direction of arrow B with the transport driven roller 41B as a fulcrum, A space for moving the image forming unit 5 is ensured by making the space between the image forming unit 5 larger than that at the time of image formation. At this time, the conveyance guide plate 71 of the conveyance guide portion 7 disposed on the upper portion of the head cleaning device 6 is also rotated upward in the direction of arrow C at the fulcrum 72, and the upper portion of the head cleaning device 6 is opened.

  Then, after the transport unit 4 and the transport guide portion 7 are released (released), the image forming unit 5 moves in the paper passing direction (arrow A direction), is stopped above the head cleaning device 6, and is cleaned. 61 rises and shifts to the cleaning operation (maintenance recovery operation) of each head module 51.

Next, the configuration of the idle discharge receiving portion according to the first embodiment of the present invention in this image forming apparatus will be described with reference to FIGS. 7 is an explanatory plan view showing the structure of the empty discharge receiving portion, and FIG. 8 is an explanatory front view.
First, as shown in FIG. 1 and FIG. 2 described above, the nozzles of the head 101 are arranged on the back side of the transport belt 43 with the transport belt 43 and the platen member 45 sandwiched between the head modules (recording heads) 51. An empty discharge receiver (waste liquid receiver) 48 that receives droplets (empty discharged droplets) that do not contribute to image formation discharged from the empty discharge operation 102 is provided.

  Here, as shown in FIG. 5, when a belt that also serves as the suction hole 46 without using an opening dedicated for idle ejection is used as the conveyance belt 43, the head 101 of the head module 51 is rotated during one rotation of the conveyance belt. The suction holes 46 are arranged so that one or more suction holes 46 always face each other at positions corresponding to the nozzles 102. Further, as shown in FIG. 6, the conveying belt 43 may be configured to have an empty discharge opening 47 corresponding to each head 101. In any configuration, by performing idle ejection at the timing when the suction hole 46 or the opening 47 is opposed to the nozzle 102, the idle ejection droplets are sucked into the suction hole 46 or the opening 47 and the platen member 45 of the transport belt 43. The ink is discharged toward the empty discharge receiving portion 48 through an opening (not shown) provided in the.

  As shown in FIGS. 7 and 8, the idle ejection receiver 48 includes an idle ejection receiver 201 that receives idle ejection droplets ejected from the head 101 of the head module 51. The empty discharge receiver 201 is a substantially rectangular box-shaped member that is arranged along a direction orthogonal to the sheet conveyance direction and has an open top surface, and is detachably attached to the support bracket 202.

  In this empty discharge receptacle 201, a full detection sensor 203 for detecting that the waste liquid of empty discharge droplets stored therein is full is disposed at a substantially central portion in a direction orthogonal to the paper transport direction. Yes. When the full detection sensor 203 detects fullness, it can be replaced with a new empty discharge receiver 201 by displaying the full empty discharge receiver on an operation panel, which will be described later, or mounted again after cleaning. it can.

  The idle discharge receptacle 201 is disposed so as to be able to incline with respect to the discharge direction of the empty discharge droplets by being rotatably supported with a support bracket 202 and a rotation shaft 211 of a leveling member described later. The idle discharge receiver rotation drive motor 204 rotates the idle discharge receiver rotation drive gear 206 attached to the motor gear 205 and the support bracket 202 to rotate the idle discharge receiver 201 and change its inclination angle. be able to. Further, a reference position detection sensor 207 for detecting the rotation reference position of the idle discharge receiver 201 is provided opposite to the idle discharge receiver rotation driving gear 206, and the idle discharge receiver is set based on the reference position detected by the reference position detection sensor 207. The rotation angle of the idle discharge receiver 201 is adjusted by controlling the drive motor for rotation 204.

  Further, a rotary shaft 211 is inserted into the empty discharge receiver 201, and a plate-like leveling member 212 for leveling the waste liquid deposits of empty discharge droplets in the empty discharge receiver 201 is disposed on the rotary shaft 211. ing. Note that “leveling” is not limited to flattening, but means reducing unevenness of the waste liquid deposit.

  Then, the leveling member 212 is rotated (reciprocally oscillated) by rotationally driving the leveling member rotation driving gear 216 attached to the motor gear 215 and the rotating shaft 211 by the leveling member rotation driving motor 214. it can. Further, a reference position detection sensor 217 for detecting the rotation reference position of the leveling member 212 is provided opposite to the leveling member rotation drive gear 216, and the leveling member is based on the reference position detected by the reference position detection sensor 217. The leveling member 212 is reciprocally swung by drivingly controlling the rotation driving motor 214 to level the unevenness of the surface of the waste liquid deposit in the empty discharge receptacle 201.

Next, the inclination angle adjustment of the idle discharge receptacle will be described with reference to FIG.
As shown in FIG. 9A, when performing the idle ejection operation, the flying path of the idle ejection droplet 301 is curved due to the influence of the circular movement of the transport belt 43, and the idle ejection droplet 301 is ejected idle. Instead of landing on the bottom surface of the receptacle 201, the landing is made on the inner surface 201a side. Here, the empty discharge droplets 301 discharged into the empty discharge receiver 201 are thickened due to evaporation of moisture and the like, and the fluidity is lowered and accumulated (the waste liquid in such a state is accumulated as “ Therefore, when the landing position of the empty ejection droplet 301 is shifted, the waste liquid 302 is also shifted.

  Therefore, as shown in FIG. 9B, the empty discharge receiver 201 is rotated (swinged) in the direction of the arrow and is inclined by the required inclination angle θ, so that the flight path is curved and flies. The droplet 301 can also land on the bottom surface side of the empty discharge receiver 201. In this case, since the curve of the flight path of the empty ejection droplet 301 depends on conditions such as the speed of the conveyor belt 43, the inclination angle of the idle ejection receiver 201 is determined according to conditions such as the speed (printing speed) of the conveyor belt 43. By changing the above, the flight path of the empty discharge droplet 301 can be directed to the bottom surface of the empty discharge receiver 201 more reliably.

Next, the leveling operation by the leveling member 212 in the idle discharge receptacle 201 will be described with reference to FIG.
When idle discharge is performed on the empty discharge receiver 201, as shown in FIG. 10A, if the empty discharge droplets 301 are discharged to the same location, the waste liquid 302 may be partially piled up. . Then, the accumulation of the waste liquid 302 proceeds without the full detection sensor 203 detecting fullness, and the empty discharge droplet 301 overflows from the empty discharge receiver 201.

  Therefore, as shown in FIG. 10B, the leveling member 212 is periodically swung so that the raised waste liquid 302 is leveled. Thereby, the full tank detection by the full tank detection sensor 203 can be accurately performed. The leveling member 212 may be an elastic material such as rubber.

Next, an overview of the control unit of the image forming apparatus will be described with reference to a block diagram shown in FIG.
The control unit 500 includes a CPU 501 that also functions as a unit for controlling the idle ejection operation according to the present invention that controls the entire apparatus, a ROM 502 that stores programs executed by the CPU 501 and other fixed data, and image data. RAM 503 for temporary storage, rewritable non-volatile memory 504 for holding data while the apparatus is powered off, image processing for performing various signal processing and rearrangement on image data, and other entire apparatus And an ASIC 505 for processing input / output signals for control.

  In addition, the head driving control unit 508 including a data transfer unit for driving and controlling each head 101 of each head module 51 constituting the recording head unit 50 and a driving signal generating unit, and each head 101 of the recording head 51 are driven. A head driver (driver IC) 509 for driving, an image forming unit moving motor driving unit 511 for driving an image forming unit moving motor 510 for moving the image forming unit 5, and transport for driving the transport belt moving motor 512. A belt moving motor driving unit 513, a suction motor driving unit 515 for driving the suction motor 514 for the suction fan 44, and an I / O 516 for inputting information from various sensors.

  Here, in the I / O 516, as sensor information, an environmental sensor (not shown) for detecting an environmental temperature and an environmental humidity, a paper sensor 521 (see FIG. 1) for detecting a paper provided in the recording head unit 50, and an idle discharge are performed. In addition, various detection signals from the phase sensor 522 for detecting the position of the suction hole 46 or the opening 47 of the transport belt 43, the full detection sensor 203 of the idle discharge receiving portion 48, the reference position detection sensors 207 and 217, etc. A detection signal is input.

  The control unit 500 is connected to an operation panel 517 for inputting and displaying information necessary for the apparatus.

  Here, the control unit 500 prints data including image data from the host side such as an information processing device such as a personal computer (hereinafter referred to as a PC), an image reading device such as an image scanner, and an imaging device such as a digital camera. The data is received by the host I / F 506 via a cable or a net.

  The CPU 501 reads and analyzes the print data in the reception buffer included in the host I / F 506, performs data rearrangement processing and the like (some image processing in some cases) by the ASIC 505, and the head. The image data is transferred to the drive control unit 508. The conversion of the print data for image output into bitmap data (print raster data) is performed by developing the image data into bitmap data using a printer driver on the host side and converting the bitmap data (print raster data) of the print data. After the creation, the print raster data is transferred to this apparatus.

  At this time, the CPU 501 analyzes in parallel the discharge nozzles used at the time of printing based on the image data, and creates an empty discharge pattern corresponding to the nozzle use frequency. The idle ejection pattern has a pattern and an amount of drops so that the drops do not concentrate in one place or a specific line or texture is not formed so that it is difficult to be recognized by human vision. The created idle ejection pattern is combined with the image data and transferred to the head drive control unit 508 as print raster data.

  Upon receiving the print raster data, the head drive control unit 508 sends this dot pattern data (print raster data) as serial data to the head driver 509 in synchronization with the clock signal, and also outputs a latch signal at a predetermined timing. The data is sent to the head driver 509.

  The head drive control unit 508 includes a ROM (can also be configured by the ROM 502) that stores pattern data of drive waveforms (drive signals), and a D / A converter that D / A converts the drive waveform data read from the ROM. A waveform generation circuit including an A converter and a drive waveform generation circuit including an amplifier and the like are included.

  The head driver 509 receives a clock signal from the head drive control unit 508 and serial data as image data, and a latch circuit that latches the register value of the shift register using a latch signal from the head drive control unit 508. A level conversion circuit (level shifter) that changes the output value of the latch circuit, an analog switch array (switch means) that is controlled to be turned on / off by the level shifter, and the like, and controls on / off of the analog switch array. As a result, a required drive waveform included in the drive waveform is selectively applied to the actuator means of the head unit 51 to drive the head, and the image data is printed to form a dot pattern.

  Further, the main control unit 500 adjusts the inclination angle of the idle discharge receiver 201 by driving and controlling the idle discharge receiver rotation drive motor 204 via the idle discharge receiver drive unit 531, and also performs a smoothing member rotation drive motor. 214 is driven and the leveling member 212 is periodically swung to level the surface of the waste liquid 302 of the empty discharge receptacle 201.

Here, an example of the inclination angle adjustment control of the idle discharge receiver by the control unit will be described with reference to the flowchart of FIG.
First, after the idle discharge receiver 201 is moved to the reference position, it is determined whether or not the inclination angle of the idle discharge receiver 201 is arbitrarily set. Note that an instruction whether or not to arbitrarily set the tilt angle is input from the operation panel 517, for example.

  If the tilt angle is not arbitrarily set, the idle discharge receiver 201 is rotated (moved) according to the printing speed to obtain a required tilt angle θ. That is, when the printing speed is fast (for example, a predetermined printing speed V1 or more), the inclination angle of the idle discharge receiver 201 is moved to a large value (the inclination angle θ is set to θ1). Further, when the printing speed is normal (for example, a predetermined printing speed V2 (V2 <V1)), the inclination angle θ of the idle discharge receiver 201 is moved inward (the inclination angle θ is changed to θ2 (θ2 <θ1)). To do.) Further, when the printing speed is not normal (for example, when the printing speed V3 (V3 <V2) set in advance), the inclination angle θ of the idle discharge receiver 201 is moved to a small value (the inclination angle θ is changed to θ3 (θ3)). <Θ2)).

  If the tilt angle is arbitrarily set, the input of the set angle is awaited, and the idle discharge receiver 201 is moved so as to be the input angle θ.

  As described above, since the empty discharge receiver is disposed so as to be tiltable with respect to the discharge direction of the empty discharge droplet, the empty discharge receiver is tilted to ensure that the empty discharge droplet that is bent by the airflow caused by the movement of the conveying means is reliably generated. Can be received and collected, and the bias of landing of empty discharge droplets can be reduced, and the full tank detection can be performed accurately, so the life of the empty discharge receiver is extended and the full tank detection becomes inaccurate. It is possible to prevent the waste liquid from overflowing.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a schematic front view of the transport unit portion in the embodiment, and FIG. 14 is a plan view of the same.
First, the housing 601 that forms a suction path for generating suction force on the transport belt 43 is provided. In the housing 601, an empty discharge receiving portion 611 that faces each head module 51 via the transport belt 43 is provided. In addition to the arrangement, a conveyance suction fan 602 which is a conveyance suction force generating means for generating a suction force for sucking the sheet by the conveyance belt 43 is disposed.

  The idle discharge receiver 611 generates an attractive force on the conveyor belt 43 and forms an attractive path for generating an attractive force for sucking empty discharged droplets, and the empty discharge receiver 613 facing each head module 51 in the housing 612. Each empty discharge receiver 613 is provided with a guide member 614 that expands upward in a substantially V shape. In the lower portion of the housing 612, the idle discharge suction fan is an idle discharge suction force generating means for generating a suction force for causing the conveyance belt 43 to suck the sheet and sucking the empty discharge droplets toward the idle discharge receiver 613. A suction force is generated in the housing 612 by disposing 615 and rotationally driving the suction fan 615.

  The side covers 603 and 603 of the housing 601 are shared with the housing 612 for the idle discharge receiving portion 611 disposed in the housing 601. Each empty discharge receptacle 613 is connected to a waste liquid storage unit (not shown) via a waste liquid tube 616.

  With this configuration, the empty discharge droplets are discharged from each head 101 of the head module 51 toward the suction hole 46 or the opening 47 of the transport belt 43 at a predetermined timing during the empty discharge operation. Fly toward the empty discharge receptacle 613. At this time, since the suction fan 614 is driven to rotate, a suction force is generated in the housing 612 in the direction toward the empty discharge receiver 613, and the suction hole 46 or the opening of the conveyor belt 43. The empty discharge droplets that have passed through 47 (and the opening (not shown) of the platen member 45) are guided by the guide member 614 and reliably collected in the empty discharge receiver 613. On the other hand, the gas accompanying the suction is sucked into the suction fan 615.

  At this time, since the idle discharge receiving suction fan 615 and the transport suction fan 602 are independent, the suction force can be individually controlled. Therefore, the suction force by the idle discharge receiving suction fan 615 is made larger than the suction force by the transport suction fan 602. That is, according to an experiment, when the suction force on the transport belt 43 in a place other than the idle discharge receiver 613 was measured using a digital force gauge, the suction force corresponding to one A4 sheet was 4 to 8 N. . Subsequently, when the reliability test was performed by adjusting the suction force on the idle discharge receiver 613 stepwise, if the suction force equivalent to one A4 sheet on the idle discharge receiver 613 is 8 N or more, the sheet floats. It has been found that good results can be obtained with little cockling and mist scattering. Therefore, it is preferable to set the suction force by the suction fans 615 and 602 so that the suction force on the idle discharge receiver 613 is approximately twice as much as the suction force other than the idle discharge receiver 613.

  In this way, the suction force generating means for transport that generates the suction force that causes the transport means to suck the recording medium, and the suction force that causes the transport means to suck the recording medium and suck the empty discharge droplets toward the empty discharge receiver. By including the generated suction force generating means for empty discharge, it is possible to reliably collect the empty discharge droplets in the empty discharge receiver.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 15 is a schematic front view of the transport unit unit in the same embodiment.
Here, a mist separator 621 as gas-liquid separation means is disposed above the idle discharge receptacle 613 in the second embodiment so that air (gas), idle discharge droplets and mist can be separated efficiently. Yes. Here, the mist separator 621 has a shape in which the plate-like members are alternately crossed in the suction direction, and the droplets and mist adhere to the plate-like members in the path that is elongated by this, and the attached droplets and mist are: Finally, it is collected in the empty discharge receptacle 613.

DESCRIPTION OF SYMBOLS 4 ... Conveyance unit 5 ... Image forming unit 43 ... Conveyor belt 44 ... Suction fan 46 ... Suction hole 47 ... Opening part 48 ... Empty discharge receiving part 50 ... Recording head unit 51, 51A, 51B, 51C, 51D ... Head module 101 ... Head 102 ... Nozzle 201 ... Empty discharge receiver 202 ... Bracket 203 ... Full tank detection sensor 212 ... Leveling member 602 ... Transport suction fan 611 ... Empty discharge receiver 612 ... Empty discharge receiver 615 ... Empty discharge suction fan

Claims (3)

A recording head for discharging droplets;
Conveying means for conveying a recording medium;
An empty discharge receiver that is disposed at a position facing the recording head via the conveying unit and receives empty discharged droplets that do not contribute to image formation discharged from the recording head toward the opening of the conveying unit. ,
The image forming apparatus, wherein the idle discharge receiver is disposed so as to be inclined with respect to a discharge direction of the empty discharge droplets from the recording head.   The image forming apparatus according to claim 1, wherein an inclination angle of the idle discharge receiver is changed according to a printing speed.   3. The image forming apparatus according to claim 1, wherein the idle discharge receiver is provided with a leveling member for leveling a surface of the stored empty discharge droplets.

Images