JP5267134B2 - Liquid jet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet recording device that surely collects idly-ejected ink and ink mist. <P>SOLUTION: An idle ejection receiving part is disposed in a position that faces a line head on the back face side opposite to a mounting surface of a conveying part, and an ink mist suction duct is provided near the idle ejection receiving part. The idle ejection receiving part receives idly-ejected ink that has passed through suction holes of a conveyor belt. The ink and ink mist idly ejected from nozzles of a plurality of heads are thereby received surely by an idle ejection receiving part angle adjusting mechanism. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a liquid jet recording apparatus that ejects ink in an idle manner.

An ink jet printer has a configuration in which printing is performed by ejecting ink from nozzles of a recording head onto a sheet conveyed by a conveying unit such as a conveying belt. In such a printer, it is important to keep the ink ejection good by preventing the nozzles of the recording head from drying. Therefore, conventionally, an ink jet printer that periodically performs an operation (so-called “empty ejection” (synonymous with preliminary ejection)) forcibly ejecting ink from nozzles in an area other than on a sheet during a printing operation has been already known. ing.
In the case of a serial inkjet printer in which the recording head moves in a direction perpendicular to the paper conveyance direction, the recording head is moved to a position that does not face the conveyance belt that conveys the paper, and idle ejection is performed. In a line-type ink jet printer in which the head for ejecting liquid droplets from a line is configured over almost the entire width of the paper, if one of them is moved so that the recording head and the conveyor belt do not face each other, the structure becomes large. There is. In view of this, a technique is known in which ink is idlely ejected from a hole array formed of a plurality of suction holes formed in a conveyance belt.

  In Patent Document 1, it is possible to efficiently suck and discharge moisture and ink mist from the nozzle surface or the recording surface even if the number of nozzles of the droplet discharge head is increased or lengthened. There is disclosed a technique capable of maintaining high image quality and high reliability without increasing the size.

JP 2004-306270 A

  However, in the conventional idle discharge mechanism, the idle discharge receiving portion is disposed on the back surface opposite to the mounting surface of the conveyance portion and facing the line head. Although it is provided to receive the empty ejected ink that has passed through the hole, wind is generated by the rotation of the transport belt, and the ink ejected by the wind does not fall vertically, but in the transport belt rotation direction. If it accumulates while adhering to the side wall of the empty discharge receiving part, it will bend and adhere to the side wall etc. of the empty discharge receiving part, causing moisture to evaporate and causing ink thickening. If the ink is full before the detection is detected and overflows from the empty discharge receiver, or if thick ink adheres to a part near the full detection, the empty discharge receiver is not full but the full detection is detected. Caused by empty discharge Ink mist generated by the rotation of the conveyor belt is generated by the rotation of the conveyor belt, and the ink mist generated by the idle ejection does not fall vertically, but flows in the conveyor belt rotation direction and adheres to the conveyor belt, thereby conveying performance due to dirt on the back side of the paper. There were problems such as a drop in discharge and non-ejection due to contamination of the head surface adhering to the line head surface.

  The present invention has been made in view of the above circumstances, and its purpose is to reliably collect a prescribed amount by a mechanism that adjusts the angle of the idle ejection receiver according to the idle ejection ink that bends. It is an object of the present invention to provide a liquid jet recording apparatus that reliably collects ink ejected in an idle manner and an ink mist by means of an ink mist suction duct provided near the idle ejection receptacle and a mechanism for adjusting the angle of the ink mist suction duct. .

The invention according to claim 1 is a liquid ejection recording apparatus that performs printing by ejecting ink from a plurality of nozzles.
A plurality of suction holes penetrating the front surface side and the back surface side, holding the paper on the front surface and transporting it to the printing unit;
A suction means for sucking air from the back surface side of the transport belt through the suction holes and sucking the paper onto the surface of the transport belt;
It has a plurality of nozzles arranged in the paper passing width direction substantially orthogonal to the paper transport direction, and ejects ink from the plurality of nozzles to the paper transported to the printing unit in the suction state by the suction means and the transport belt. An inkjet head for printing at a printing position,
An empty discharge receiving portion that is disposed at a position corresponding to a plurality of nozzles on the inner side of the conveying belt, and receives ink ejected from the nozzles and passed through the suction holes of the conveying belt;
Ink is ejected from the nozzles at a timing when there is no paper at the print position and the suction hole of the transport belt is located at the print position, with the rotation timing of the transport belt and the ink discharge timing from the plurality of nozzles of the inkjet head. Control means for controlling
An idle discharge receiving angle adjustment mechanism for adjusting the angle of the idle discharge receiving portion with respect to the ink discharge direction from the inkjet head;
With
The idle discharge receiving portion is disposed along a direction orthogonal to the paper conveyance direction, and has an opening for receiving the idle discharged ink .
The mist recovery suction duct for recovering the mist generated at the time of preliminary ejection, a liquid jet recording apparatus characterized by comprising in the vicinity of the air discharge receiver.

A second aspect of the present invention is the liquid-jet recording apparatus according to claim 1, mist collecting suction duct, characterized in that provided in the vicinity of the downstream side of the air discharge receiving portion in the sheet conveyance direction.

According to a third aspect of the present invention, in the liquid jet recording apparatus according to the first or second aspect , the mist collection / suction duct includes a filter member provided inside the mist collection / suction duct.

According to a fourth aspect of the present invention, in the liquid jet recording apparatus according to any one of the first to third aspects, the mist collection / suction duct is detachable together with the idle discharge receiving portion.

  A mechanism that adjusts the angle of the idle discharge receiver according to the bent empty discharge ink reliably collects the specified amount, and the ink mist suction duct and ink provided in the vicinity of the empty discharge receiver according to the flowing ink mist By the mechanism for adjusting the angle of the mist suction duct, it is possible to reliably collect the ink and ink mist that are ejected in an idle manner.

1 is a schematic overall side view of a line-type inkjet image forming apparatus in an embodiment of the present invention. 1 is a schematic overall plan view of a line-type inkjet image forming apparatus. It is the schematic of an empty discharge droplet receiving part (a suction duct is included) structure. It is the schematic of an empty discharge droplet receiving part angle adjustment operation (suction duct). It is the schematic of empty discharge droplet receiving part scraping operation | movement. It is an empty discharge droplet receiving part angle adjustment operation flowchart.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic overall side view of a line-type inkjet image forming apparatus (having a plurality of recording heads in which nozzle rows are arranged orthogonal to the paper transport direction).

  FIG. 2 is a schematic overall plan view of a line-type inkjet image forming apparatus (having a plurality of recording heads in which nozzle rows are arranged orthogonal to the paper transport direction).

  This ink jet image forming apparatus is a line type ink jet image forming apparatus in which a head for ejecting liquid droplets from nozzles forms a line configuration over almost the entire width of a recording medium.

  The inkjet image forming apparatus includes an apparatus main body, a paper feed tray on which recording media are stacked and fed, a paper ejection tray on which printed recording media are ejected and stacked, and conveyance for conveying the recording medium from the paper feeding tray to the paper ejection tray. And a head unit that discharges and prints droplets on a recording medium during the conveyance, and a head cleaning device that cleans the nozzles of the head.

  The apparatus main body is composed of front and rear side plates and stays (not shown), and the recording medium loaded on the paper feed tray is sent to the transport unit one by one at the separation roller and paper feed roller.

  The transport unit includes a transport drive roller, a transport driven roller, and an endless belt, and the endless belt is stretched between the transport drive roller and the transport driven roller. A plurality of suction holes are formed on the surface of the endless belt, and a suction fan for sucking a recording medium is formed below the endless belt, and the recording medium on the endless belt is conveyed while being sucked by the suction fan. The Further, a conveyance guide roller is formed on a guide (not shown) by its own weight above the conveyance drive roller and the driven roller. When the transport driving roller is rotated by a motor (not shown), the transport slave roller and the transport guide roller are driven and rotated to transport the recording medium.

  A head unit for discharging droplets to be printed on a recording medium is formed on the upper part of the transport unit. Further, the head portion is movable in the recording medium passing direction, and is located up to the upper portion of the head cleaning device when the head nozzle surface is later cleaned. Move on the ride. In the head portion, a head for discharging droplets is formed over almost the entire width of the recording medium, and five heads are arranged in each row (heads 1, 2, 3, 4, 5). It is arranged in a row (heads a, b, c, d). Here, yellow (Y) and magenta (M) are used for the head a (1-5) and the head b (1-5), and cyan (C) is used for the head c (1-5) and the head d (1-5). ) And black (K), and a staggered arrangement forms an image line of 150 dpi. The head configuration is not limited to these examples, and a configuration in which two heads are arranged and one color ink is put in each head and the image resolution is increased may be used. Branch pipes for supplying ink to the respective heads are arranged for each color (branch pipes a to d) above the heads, and the branch pipes and the heads are connected by supply tubes. A sub tank is disposed upstream of the branch pipe, and a negative pressure appropriate to hold the meniscus of the nozzle of the head is maintained by a water head difference between the sub tank and the head. Further, a main tank for storing ink is arranged on the upstream side of the sub tank. Both are connected by a supply path using tubes.

  Further, the configuration of the head may be a single head in which nozzles are arranged over almost the entire width of the recording medium. One head has a droplet of one color. Here, four colors of yellow, magenta, cyan, and black are used, and the configuration of four heads is provided.

  A conveyance guide unit that discharges the recording medium to a sheet discharge tray is formed on the downstream side of the conveyance unit. The recording medium conveyed by the conveyance guide unit is discharged to a discharge tray. The paper discharge tray is composed of a pair of side fences that regulate in the width direction of the recording medium and an end fence that regulates the leading end of the recording medium.

  A head cleaning device for cleaning the nozzle surface of the recording head is provided at the lower portion of the conveyance guide portion. Head cleaning means a, b, c, and d are arranged in accordance with each head, and the head cleaning means is arranged in a staggered arrangement over almost the entire width of the recording medium in the same manner as the head (FIGS. 1 and 2). Suction pumps a, b, c, and d are arranged below the respective cleaning means for supplying ink to the head.

  After printing, when the head that discharges droplets is capped and ink is sucked, or when ink that adheres to the nozzle surface of the head is cleaned with a wiper blade (not shown), after the printing is stopped, the transport unit moves the transport driven roller. Is turned in the direction of the arrow downward B to secure the movement space of the head part. In addition, the conveyance guide portion arranged at the upper part of the cleaning device is also rotated at the fulcrum in the arrow C direction and released. After the conveyance unit and the conveyance guide unit are released, the head unit moves in the recording medium sheet passing direction A, moves to the upper part of the cleaning device, becomes fixed, and moves to the cleaning operation of each head.

Also, when performing idle ejection to restore the ejection performance from the recording head nozzles during printing, the multiple suction holes formed on the endless belt surface of the transport section restore the ejection performance of the nozzles from the head nozzles. It is also used to pass the ink ejected in order to pass. The ink ejected from the head after passing through the suction holes on the surface of the endless belt is received by the idle ejection receiver disposed in the same direction as the head arrangement direction.
Thereby, stable ink discharge can be performed.

FIG. 3 is a schematic diagram of a configuration of an empty discharge droplet receiving unit (including a suction duct).
Since the four colors of yellow, magenta, cyan, and black have four heads, it is necessary to have a structure corresponding to four colors for receiving the ejected droplets.

  Ink ejected idle from a recording head nozzle (not shown) passes through a conveyance belt suction hole and a conveyance face plate suction hole (not shown) and can be collected by an empty ejection droplet container. The empty discharge droplet container is a rectangular box-shaped member, and an opening is formed in the upper surface and the rotation shaft portion. The upper surface opening is disposed at a position opposite to a conveyance face plate opening (not shown).

  Since the empty discharge droplet container is detachably supported by the empty discharge droplet receiving support bracket, the empty discharge droplet container can be detached when the empty discharge droplet container is full, and a new empty discharge droplet container can be mounted. At this time, the waste liquid accumulated in the empty discharge droplet container can be discarded, and then the empty discharge droplet container that has been washed can be installed again.

  The full detection of the empty liquid drop container is performed by detecting the full capacity of the empty liquid drop container by using an empty discharge liquid full capacity detection sensor attached to the center of the empty discharge liquid receiving support bracket in the direction perpendicular to the paper transport direction. Thus, when full, the full empty discharge droplet container is displayed on an operation panel (not shown), so that a new empty discharge droplet container is replaced.

  Regarding the angle adjustment mechanism of the empty discharge droplet container, the empty discharge receiving rotation driving gear provided in the empty discharge droplet receiving support bracket, the empty discharge receiving rotation driving motor for driving the empty discharge receiving rotation driving gear, and the empty discharge By providing a scraping rotation reference position detection sensor for detecting the reference position of the receiving rotation drive gear, the reference angle of the empty discharge droplet container is detected, and the empty discharge receiving rotation drive motor is driven to thereby detect the empty discharge droplet. The angle of the container can be adjusted.

  In addition, a rotary shaft and a scraping plate-like member are provided in the empty discharge droplet container, and the rotation shaft rotates periodically so that the liquid droplets accumulated in the empty discharge droplet container are not accumulated unevenly. As a result, it is possible to level the accumulated liquid droplets biased by the scraping plate member provided on the rotating shaft. The scraping plate member may be an elastic material such as rubber. The rotary shaft is attached to the empty discharge droplet receiving support bracket, the scraping shaft driving gear is provided at the end of the rotating shaft, and further the scraping shaft driving motor and scraping rotational drive for driving the scraping shaft driving gear. By providing a scraping rotation reference position detection sensor for detecting the gear reference position, the reference position of the scraping plate-like member is detected, and the rotary shaft drive motor is driven to scrape and reciprocate the empty discharge container. Can be performed.

  Further, the suction duct has two configurations of a suction duct (1) and a suction duct (2). The suction duct (1) is provided with a filter for collecting ink mist and can be attached to and detached from a suction duct (2) (not shown). The suction duct (1) also has a detachable connection portion (not shown) that can be attached to and detached from the empty discharge droplet container. When the filter of the suction duct (1) is soiled, the suction duct (1) is sucked into the suction discharge droplet container. The suction duct can be attached again after being attached to and detached from the filter (2) and replaced with a new filter. When the empty discharge container is removed when it is full and a new empty discharge container is installed, the suction duct (1) and the empty discharge container can be replaced while being connected.

  Since the angle of the empty discharge droplet container can be adjusted, the angle of the suction duct (1) connected to the empty discharge droplet container can also be adjusted in conjunction. It is also possible to adjust the angle by driving the suction duct (1) separately from the angle adjustment of the empty discharge droplet container by a mechanism not shown.

  In the suction duct (2), a detachable (not shown) is connected to the suction duct (1) by a connecting portion, and is provided from the connecting portion to the fan suction port. The suction fan may be used in combination with the suction force of the paper suction fan, or may be independently provided with an ink mist suction fan. Since the suction duct (2) is movable by adjusting the angle, the suction duct (2) can be adapted to the angle adjustment by using a flexible material, a mechanism such as a bellows tube.

  FIG. 4 is a schematic diagram of the empty discharge droplet receiving unit angle adjustment operation (suction duct).

  In the idle ejection operation, due to the influence of the speed of the conveying belt (not shown), the idle ejection ink does not land on the bottom surface of the idle ejection droplet container due to the curved path of the idle ejection ink, etc. In some cases, therefore, curved empty discharge ink can be landed on the bottom surface of the empty discharge droplet container by changing the angle of the empty discharge droplet container according to conditions such as the speed of the transport belt. Similarly, the ink mist generated at the time of idle ejection is similarly curved due to the speed of the conveying belt (not shown), and further scatters and adheres to the surface of the conveying belt, resulting in a decrease in conveying performance due to dirt on the back surface of the paper and the head. Since there is a problem such as non-ejection due to head surface contamination due to adhesion to the surface, it is curved by varying the angle of the suction duct in conjunction with varying the angle of the empty ejection droplet container according to conditions such as the speed of the conveyor belt The empty ink mist thus collected can be collected by the suction duct without being scattered. As for the variable angle of the suction duct, the angle is changed in conjunction with the empty discharge droplet container in the illustration, but the angle of the empty discharge droplet container can be changed by providing a variable mechanism (not shown). The angle can be changed differently.

  The operation is to detect the reference positions of the idle discharge receiving rotation drive gear rack and the idle discharge receiving rotation drive gear rack and the idle discharge receiving rotation drive gear for driving the idle discharge receiving rotation drive gear rack provided on the empty discharge droplet receiving support bracket. By providing a scraping rotation reference position detecting sensor for detecting the reference angle of the empty discharge droplet container, the angle of the empty discharge droplet container is varied by driving the empty discharge receiving rotation driving motor. The angle to be set is set to be variable at a large angle in accordance with the conveyor belt speed, since the mist scattering decreases when the conveyor belt speed is low, and the mist scattering increases when the conveyor belt speed is high. It is also possible to adjust by other conditions, a control panel (not shown) or the like.

  As for the variable operation of the suction duct angle, the angle of the empty discharge droplet container can be varied by driving the empty discharge receiving rotation drive motor in the same manner as the empty discharge droplet container angle adjusting operation in order to attach the suction duct to the empty discharge droplet container. By doing so, the suction duct angle can be varied at the same time. The angle to be set is set to be variable according to the conveyance belt speed. It is also possible to adjust by other conditions, a control panel (not shown) or the like.

FIG. 5 is a schematic diagram of the scraping operation of the empty discharge droplet receiving portion.
In normal empty discharge operation, empty discharge ink may be piled up in a part as shown in the figure, so the empty discharge droplet container before the detection with the appropriate amount of empty discharge liquid full detection sensor operates normally In some cases, the empty main discharge ink may overflow, and by periodically rotating the rotating shaft, it becomes possible to smooth the uneven accumulated ink by the scraping plate member provided on the rotating shaft. . The scraping plate member may be an elastic material such as rubber. As for the rotational operation of the rotary shaft, a scraper rotary shaft drive gear is provided at the end of the rotary shaft, and further, a scraper rotary shaft drive motor for driving the scraper rotary shaft drive gear and a reference position of the scraper rotary drive gear are detected. By providing the scraping rotation reference position detection sensor, the reference position of the scraping plate-like member is detected, and the rotary shaft drive motor is driven to perform the scraping reciprocating operation in the empty discharge droplet container, thereby enabling the empty discharge liquid. The detection by the appropriate amount full detection sensor can operate normally.

  FIG. 6 is a flowchart of the empty discharge droplet receiving unit angle adjustment operation.

  First, after the start, the empty discharge receiver detects the reference angle of the empty discharge droplet container by the rotation reference position detection sensor and moves to the reference position (S601).

  When the printing speed is input through a control panel (not shown) or the like (S602, S603), the angle of the empty discharge droplet container is set by driving the empty discharge receiving rotation driving motor to the empty discharge receiving angle (setting value) corresponding to the printing speed. The variable discharge adjustment angle is varied and the process ends (S604, S605, S606).

  By inputting an arbitrary angle adjustment value of the idle discharge receiver via a control panel (not shown) or the like (S607), it is possible to adjust the idle discharge reception angle at an arbitrary set value regardless of the printing speed (S608). .

According to the present embodiment, the ink mist suction duct is provided adjacent to the idle ejection receiver having the receiving surface angle adjusting mechanism for the idle ejection receiver with respect to the angle in the ink ejection direction from the head, and the idle ejection is performed. Since the ink mist suction duct mechanism for adjusting the angle in conjunction with the adjustment of the receiving angle is provided, it is possible to reliably collect ink and ink mist that have been ejected idle and bent by the conveying air.
As a result, ink and ink mist ejected from the nozzles of a plurality of heads are reliably received by the idle ejection receiving part, and a specified amount of ink is collected and the inside of the machine is stained by the ink mist suction duct (recording head, transport belt, etc. ) Can be prevented.

  Each embodiment described above is a preferred embodiment of the present invention, and various modifications can be made without departing from the gist of the present invention.

Claims (4)

In a liquid jet recording apparatus that performs printing by ejecting ink from a plurality of nozzles,
A plurality of suction holes penetrating the front surface side and the back surface side, holding the paper on the front surface and transporting it to the printing unit;
A suction means for sucking air from the back surface side of the transport belt through the suction hole and sucking the paper onto the surface of the transport belt;
A plurality of nozzles arranged in a sheet passing width direction substantially orthogonal to a sheet conveying direction, and the plurality of nozzles for a sheet conveyed to the printing unit in an adsorbed state by the suction unit and the conveying belt; An ink jet head that ejects ink from the ink and performs printing at a printing position;
An empty discharge receiving portion that is disposed at a position corresponding to the plurality of nozzles on the inner side of the conveyance belt, and that receives ink discharged from the nozzles and passing through the suction holes of the conveyance belt;
The rotation timing of the transport belt and the discharge timing of ink from the plurality of nozzles of the inkjet head are the timing when there is no paper at the print position and the suction hole of the transport belt is disposed at the print position, Control means for controlling the ink to be ejected from the nozzles;
An idle discharge receiving angle adjustment mechanism for adjusting an angle of the idle discharge receiving portion with respect to an ink discharge direction from the inkjet head;
With
The idle discharge receiving portion is disposed along a direction orthogonal to the paper transport direction and has an opening for receiving the idle discharged ink,
A liquid jet recording apparatus comprising a mist collection / suction duct for collecting mist generated during the idle discharge in the vicinity of the idle discharge receiving portion.   2. The liquid jet recording apparatus according to claim 1, wherein the mist collection suction duct is provided in the vicinity of the downstream side of the idle discharge receiving portion in the paper transport direction. 3. The liquid jet recording apparatus according to claim 1, wherein the mist collection / suction duct is provided with a filter member inside the mist collection / suction duct . 4. The liquid jet recording apparatus according to claim 1, wherein the mist collection suction duct is detachable together with the idle discharge receiving portion . 5.

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