JP2006231666A - Inkjet recording device - Google Patents

Abstract

Ink jet capable of improving conveyance accuracy of a recording medium by suppressing the vibration of the conveyance belt by sucking the conveyance belt with a constant suction force without changing an adsorption force between the recording medium and the conveyance belt. A recording device is provided.
SOLUTION: A recording medium conveying means CV for conveying a recording medium P attracted to an endless conveying belt V by the action of static electricity, and ink droplets are ejected from nozzles onto the recording medium P conveyed by the recording medium conveying means CV. And an ink jet recording apparatus having a recording head HD for recording, wherein a magnetic layer having magnetism is formed on the conveyor belt V, and is opposed to the magnetic layer on the inner side of the conveyor belt V. A belt vibration suppression means AT that suppresses the vibration of the conveyor belt V by sucking the layer is provided.
[Selection] Figure 1

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to a transport apparatus that transports a recording medium placed on a transport belt.

In recent years, inkjet recording apparatuses that perform recording on a recording medium by ejecting ink droplets from nozzles have become widespread.
In this inkjet recording apparatus, conventionally, in a conveying apparatus that conveys a recording medium, a voltage is applied to an electrode provided on the conveying belt to adsorb the recording medium to the conveying belt, and the conveying belt is sucked to a belt suction unit. There is a technique for suppressing the vibration of the conveyance belt during conveyance of the recording medium (see, for example, Patent Document 1).
JP 2002-14574 (pages 6-7, FIG. 2 and FIG. 3)

In the transport apparatus described in Patent Document 1, the suction of the recording medium to the transport belt and the suction of the transport belt to the belt suction means are based on the action of electrostatic suction force.
Here, in the electrostatic attraction force, even if a voltage having the same value is applied to the electrodes, the adsorption force of the recording medium to the conveyance belt changes depending on the humidity, the material of the recording medium, and the like. Therefore, in order to always obtain a constant adsorption force, it is conceivable to change the voltage value applied to the electrode according to the humidity and the material of the recording medium.

  However, if the voltage value applied to the electrodes is changed, the suction force of the conveyor belt to the belt suction means changes, making it difficult to maintain a constant suction force. If this suction force is weakened, the effect of suppressing the vibration of the conveyor belt is reduced. Conversely, if the suction force is increased, the frictional resistance between the conveyor belt and the belt suction means increases, and the recording medium This hinders smooth transport.

That is, in the transport device described in Patent Document 1, when the suction force of the recording medium to the transport belt is changed, the suction force of the transport belt to the belt suction means also changes, and the transport accuracy of the recording medium is increased. There is an unsolved problem that it is difficult to improve.
The present invention has been made to solve the above-described problem, and suppresses vibration of the conveyor belt by sucking the conveyor belt with a constant suction force without changing the suction force between the recording medium and the conveyor belt. Another object of the present invention is to provide an ink jet recording apparatus capable of improving the conveyance accuracy of a recording medium.

  According to a first aspect of the present invention, there is provided a recording medium conveying means for conveying a recording medium attracted to an endless conveying belt by the action of static electricity, and ink droplets are ejected from the nozzles onto the recording medium conveyed by the recording medium conveying means. An ink jet recording apparatus having a recording head for recording, wherein a magnetic layer having magnetism is formed on the transport belt, and is opposed to the magnetic layer inside the transport belt, and the magnetic layer is formed by a magnetic force. A belt vibration suppression unit that sucks and suppresses vibration of the conveyor belt is provided.

In the first invention, the recording medium is conveyed by being attracted to the conveying belt by the action of static electricity. In addition, belt vibration suppression means for suppressing the vibration of the conveyor belt by attracting the magnetic layer by magnetic force is provided inside the conveyor belt having the magnetic layer.
That is, the suction force by which the belt vibration suppressing unit sucks the conveyance belt is not affected by the strength of the adsorption force of the recording medium to the conveyance belt. Therefore, it is possible to reduce the vibration of the conveyance belt without changing the adsorption force of the recording medium to the conveyance belt.

According to a second aspect, in the first aspect, the magnetic layer is formed on an inner peripheral surface of the transport belt.
In the second aspect of the invention, since the magnetic layer is formed on the inner peripheral surface of the conveyance belt, the belt vibration suppressing means disposed inside the conveyance belt attracts the magnetic layer to the inside and vibrates the conveyance belt. Can be suppressed.

  According to a third invention, in the first or second invention, the recording head is capable of forming dots in which the plurality of nozzles are aligned in one row in a main scanning direction orthogonal to the conveyance direction of the recording medium. The belt vibration suppressing means has a configuration in which the belt vibration suppression means is opposed to at least the area where the recording head performs recording on the recording medium along a direction crossing the conveyance direction. It is characterized by being arranged.

In the third aspect of the invention, the recording heads are arrayed over a distance over which the plurality of nozzles straddle the recording medium along a direction intersecting the recording medium conveyance direction. The belt vibration suppressing means is disposed so as to face the area where the recording head records on the recording medium from the inside of the conveyance belt.
Therefore, it is possible to apply a suction force to the conveying belt over the area where the recording head records on the recording medium.

According to a fourth invention, in any one of the first to third inventions, the belt vibration suppressing means is configured to form a magnetic circuit with a magnetic force generating portion and a magnetic yoke. .
In the fourth aspect of the invention, since the belt vibration suppressing means is configured to form a magnetic circuit with the magnetic force generator and the magnetic yoke, the magnetic flux leaking from the magnetic circuit can be suppressed low, and the magnetic force is reduced to the ink jet recording apparatus. It is possible to prevent other configurations and the influence on the environment outside the inkjet recording apparatus.

In addition, since the magnetic flux leaking from the magnetic circuit can be kept low, it is possible to efficiently apply the attractive force for attracting the conveyor belt.
A fifth invention is characterized in that, in the fourth invention, the magnetic force generator is formed of a permanent magnet.
In the fifth aspect of the invention, since the magnetic force generator is composed of a permanent magnet, it is possible to suppress vibration of the conveyor belt without requiring energy other than magnetism.

In a sixth aspect based on the fourth aspect, the magnetic force generator includes an electromagnet, a power source that supplies a current to the electromagnet, and a current adjusting unit that changes the amount of the current. It is characterized by that.
In the sixth aspect of the invention, the amount of current supplied from the power source to the electromagnet is adjusted by the current adjusting means. That is, it is possible to easily change the suction force with which the belt vibration suppressing means sucks the transport belt.

  Therefore, for example, the suction force can be set for each individual ink jet recording apparatus in accordance with the degree of vibration of the conveyance belt, and it is possible to reduce the variation in recording quality among the individual ink jet recording apparatuses. . Also, for example, if the supply of current to the electromagnet is stopped during maintenance such as exchanging the conveyor belt, the conveyor belt is released from the suction force from the belt vibration suppression means, and maintenance can be performed easily. Is possible.

According to a seventh aspect, in the fourth aspect, the magnetic force generation unit is a magnetic force generation roller that includes a cylindrical permanent magnet and is configured to be rotatable with the rotation of the conveyance belt.
In the seventh aspect of the invention, since the magnetic force generator is composed of a magnetic force generation roller that is provided with a cylindrical permanent magnet and can rotate as the conveyor belt rotates, the frictional resistance between the belt vibration suppression means and the conveyor belt is reduced. This can improve the conveyance accuracy of the recording medium.

According to an eighth invention, in any one of the first to seventh inventions, the belt vibration suppressing means is disposed in contact with the magnetic layer.
In the eighth aspect of the invention, since the belt vibration suppressing means is disposed in contact with the magnetic layer, leakage of magnetic flux between the belt vibration suppressing means and the magnetic layer can be minimized, and vibration of the conveyor belt can be efficiently performed. It is possible to reduce well.

A ninth invention is the invention according to any one of the first to seventh inventions, wherein the belt vibration suppressing means includes a nonmagnetic layer formed of a material having nonmagnetic properties and a low friction coefficient between the belt and the magnetic layer. And is arranged in contact with the conveyor belt.
In the ninth aspect of the invention, since the belt vibration suppression means is disposed in contact with the conveyance belt via the nonmagnetic layer, the frictional resistance between the belt vibration suppression means and the conveyance belt can be reduced, and recording is performed. The accuracy of conveying the medium can be improved.

  A tenth aspect of the invention is the linear scale according to any one of the first to ninth aspects, wherein the linear scale is disposed on the conveyance belt and has a plurality of scales formed at predetermined intervals along the conveyance direction of the recording medium. An encoder that optically detects a scale and outputs a detection signal; a conveyance position grasping unit that grasps a conveyance position of the recording medium that is sucked and mounted on the conveyance belt based on the detection signal; A head driving means for driving the recording head so that the ink droplets are ejected from the nozzles at a timing when the transport position grasped by the transport position grasping means becomes a transport position suitable for the recording; The linear scale is formed of a material having a magnetic property, faces the linear scale, and attracts the scale with a magnetic force to Characterized by being arranged to suppress scale vibration suppressing means the vibration of the near-scale.

  In the tenth invention, the encoder optically detects the magnetic scale formed on the linear scale and outputs a detection signal. The transport position of the recording medium is grasped based on the detection signal, and ink droplets are ejected toward the recording medium at a timing when the transport position becomes a transport position suitable for recording. Furthermore, a scale vibration suppressing means that suppresses the vibration of the linear scale by attracting the scale with a magnetic force is disposed to face the linear scale.

Therefore, the vibration of the linear scale is suppressed by the scale vibration suppressing means, the scale can be stably detected by the encoder, and the conveyance accuracy of the recording medium can be further improved.
An eleventh invention is characterized in that, in the tenth invention, the scale vibration suppressing means is configured to form a magnetic circuit by a magnetic force generating part and a magnetic yoke.

In the eleventh aspect of the invention, since the scale vibration suppressing means is configured to form a magnetic circuit with the magnetic force generator and the magnetic yoke, the magnetic flux leaking from the magnetic circuit can be suppressed low, and the magnetic force It is possible to prevent other configurations and the influence on the environment outside the inkjet recording apparatus.
In addition, since the magnetic flux leaking from the magnetic circuit can be kept low, it is possible to efficiently apply the attractive force for attracting the linear scale.

In a twelfth aspect based on the eleventh aspect, the magnetic force generator is formed of a permanent magnet.
In the twelfth aspect, since the magnetic force generator is composed of a permanent magnet, it is possible to suppress the vibration of the linear scale without requiring energy other than magnetism.
In a thirteenth aspect based on the eleventh aspect, the magnetic force generator includes an electromagnet, a power source that supplies current to the electromagnet, and current adjusting means that changes the amount of the current. It is characterized by that.

In the thirteenth aspect, the amount of current supplied from the power source to the electromagnet is adjusted by the current adjusting means. That is, it is possible to easily change the suction force for the scale vibration suppressing means to suck the linear scale.
Therefore, for example, the suction force can be set for each individual ink jet recording apparatus according to the degree of vibration of the linear scale, and it is possible to reduce the variation in recording quality among the individual ink jet recording apparatuses. . Also, for example, if the current supply to the electromagnet is stopped during maintenance such as replacing the linear scale, the linear scale is released from the suction force from the scale vibration suppression means, and maintenance can be performed easily. Is possible.

In a fourteenth aspect based on any one of the tenth to thirteenth aspects, the scale vibration suppression means is interposed between a nonmagnetic layer and a nonmagnetic layer formed of a material having a low friction coefficient. In contact with the linear scale.
In the fourteenth aspect, since the scale vibration suppression means is disposed in contact with the linear scale via the nonmagnetic layer, the frictional resistance between the scale vibration suppression means and the linear scale can be reduced, and recording is performed. Further improvement of the medium conveyance accuracy is achieved.

An embodiment of the present invention will be described with reference to the drawings, taking a line type ink jet recording apparatus as an example.
As shown in FIG. 1A, which is a plan view, and FIG. 1B, which is a front view, the ink jet recording apparatus 1 according to the first embodiment of the present invention includes a gate roller GR, a pressure roller PR, and a sheet conveyance. A section CV and a recording head HD are provided. In FIG. 1, the X direction indicates the conveyance direction of the recording paper P, and the Y direction indicates the main scanning direction orthogonal to the X direction.

Further, as shown in FIG. 2 which is a block diagram, the inkjet recording apparatus 1 has a recording information storage for storing recording information from a paper feeding unit KS, a transport unit driving motor Mo, a paper discharging unit EJ, and an external device. Part BF.
Here, the detail of each said structure is demonstrated.
As shown in FIGS. 1A and 1B, the recording head HD includes a head unit HDK that ejects black ink droplets, a head unit HDC that ejects cyan ink droplets, and a magenta ink droplet. And a head unit HDY that discharges yellow ink droplets.

Here, the arrangement of the nozzles provided in each head unit HDK, HDC, HDM and HDY will be described.
Each head unit HDK, HDC, HDM, and HDY has nozzles NZ that eject ink droplets of each color at predetermined intervals over a distance KY in the Y direction, as shown in FIG. 3 which is a bottom view of the recording head HD. It is formed with. This distance KY is the length of the nozzle row formed by arranging the nozzles NZ in the Y direction, and is the recording width in the Y direction of the inkjet recording apparatus 1.

In FIG. 3, the size of the nozzle NZ is exaggerated and the number thereof is reduced for easy understanding of the configuration.
The head units HDK, HDC, HDM, and HDY are arranged in this order so that the nozzle rows are aligned at predetermined intervals in the X direction over the distance KX.
Here, an area surrounded by the recording width KY in the Y direction and the distance KX is referred to as a recording area KR in the inkjet recording apparatus 1.

As shown in FIG. 1B, the recording head HD having the above-described configuration has a surface on which the nozzles NZ of the head units HDK, HDC, HDM, and HDY shown in FIG. 3 are formed on the paper transport unit CV. The nozzle surface NZP is arranged toward the recording surface PP of the recording paper P.
In addition, as these head units HDK, HDC, HDM, and HDY, a head unit that applies ink pressure by a piezoelectric element, a heating element, or the like to eject ink droplets can be employed.

As shown in FIG. 2, in the recording head HD having the above-described configuration, the head units HDK, HDC, HDM, and HDY are individually controlled by the head control unit HDD that has received a recording command from the CPU, and recording from an external device is performed. Based on the information, recording is performed by selectively ejecting ink droplets from the nozzle NZ.
As shown in FIG. 1A, the paper transport unit CV is disposed on the upstream side in the X direction of the drive roller DS and the drive roller DS to which power is transmitted from the transport unit drive motor Mo. A driven roller FS, a driving belt DS and a conveying belt V that is passed over the driven roller FS, and a charging roller SR that supplies electric charges to the conveying belt V.

Here, although not shown, the drive roller DS and the driven roller FS are rotatably held in the housing by a bearing.
Further, although not shown, the driven roller FS is applied with a force in the upstream direction in the X direction in order to apply tension so as not to loosen the conveying belt V that is passed between the driven roller FS and the driving roller DS.

The charging roller SR is disposed opposite to the driven roller FS connected to the ground so as to sandwich the conveying belt V and abut on the conveying belt V, and is connected to the belt charging power source PS.
In the belt charging power source PS, as shown in FIG. 2, charge supply to the conveyor belt V is controlled by a charging power source control unit PSD that receives a charging command from the CPU. The conveying belt V that has received the electric charge generates an adsorbing force that adsorbs the recording paper P.

  As shown in FIG. 2, the conveyance unit drive motor Mo is driven by a motor control unit MD that receives a conveyance unit drive command from the CPU, and drives the paper conveyance unit CV. The paper transport unit CV receives the recording paper P adsorbed and placed on the transport belt V by rotating the transport belt V counterclockwise as viewed in FIG. 1B by the power of the transport unit drive motor Mo. Transport in the X direction, which is the transport direction.

Further, as shown in FIGS. 1A and 1B, the paper transport unit CV controls an index sensor IS that outputs an index signal serving as a reference for the origin of rotation of the transport belt V and a transport position of the recording paper P. And a linear encoder LE that outputs a conveyance position signal.
The index sensor IS is composed of, for example, an optical sensor including a light emitting element such as a photo interrupter and a light receiving element, and is controlled by a sensor control unit SD shown in FIG. As shown in FIG. 1A, the index sensor IS outputs when the index part ID provided in a convex shape on one side edge of the conveyor belt V blocks the optical axis between the light emitting element and the light receiving element. Change the voltage. The index signal uses the change in the output voltage and triggers the timing for supplying the recording paper P to the paper transport unit CV.

  The linear encoder LE changes the output voltage in a pulse shape when the optical axis of the optical sensor is blocked and the amount of light received by the light receiving element changes by a predetermined amount. This linear encoder LE is controlled by the encoder control unit ED shown in FIG. 2, optically detects a scale engraved at a predetermined interval on a linear scale LS, which will be described later, and outputs an output voltage that changes in a pulse shape as a detection signal. To do.

  The linear scale LS is provided over the entire circumference of the outer periphery of the transport belt V on the side edge opposite to the side edge on which the index portion ID of the transport belt V is provided. This linear scale LS is a diagram showing the details of part C in FIG. 1 (a). As shown in FIG. 4, a plurality of scales SC are transported at a predetermined interval in the X direction on a scale substrate BS having optical transparency. It is engraved over the entire circumference of the belt V.

That is, when the conveyor belt V is rotated once, the output voltage output from the linear encoder LE is pulsed rising (ON state) and falling (OFF state) as many times as the number of scales SC.
Accordingly, by counting the detection signals after the above-described index signal is output, the transport position of the recording paper P that is sucked and placed on the transport belt V can be grasped.

In FIG. 4, the scale SC is hatched for easy understanding of the configuration.
Moreover, the broken line to which the code | symbol ST was attached | subjected in C part in Fig.1 (a) has shown the arrangement | positioning position of the scale suction part mentioned later.
As shown in FIG. 5 which is a diagram showing the details of the A part in FIG. 1B, the belt suction part AT has three magnetic force generating parts AG composed of the permanent magnet MG and the yoke YK in the transport direction. The support plate SB is arranged in parallel in the X direction.

As shown in FIG. 5, the yoke YK is formed with a concave end shape from a horizontal central portion YKc and side plate portions YKs1 and YKs2 extending upward from both ends in the X direction of the central portion YKc. A permanent magnet MG is disposed on the upper surface to form a magnetic circuit.
As shown in FIG. 5, the permanent magnet MG has an N pole and an S pole formed in the vertical direction, and has a thickness so as to be the same height as the upper surfaces of the side plate portions YKs1 and YKs2 in the state of being disposed on the yoke YK. Is set.

  Here, as shown in FIG. 5, the transport belt V includes a magnetic layer ML formed of a magnetic material such as a metal foil, and a belt layer VL formed of a dielectric material such as a resin outside the magnetic layer ML. , And is configured. As described above, when the charge is supplied from the belt charging power supply PS via the charging roller SR, the conveyance belt V is charged with the belt layer VL made of a dielectric, and the recording paper P is adsorbed to the belt layer VL. Is done. In FIG. 5, the thickness of the conveyor belt V is exaggerated for easy understanding of the configuration.

  In the belt attracting portion AT, the permanent magnet MG and the yoke YK are disposed in contact with the magnetic layer ML of the transport belt V as shown in FIG. At this time, the flow FL of magnetic flux from the N pole of the permanent magnet MG is divided into left and right within the bottom of the yoke YK as shown in FIG. 5, and flows along the shapes of the side plates YKs1 and YKs2 of the yoke YK, It reaches the south pole via the magnetic layer ML. The permanent magnet MG and the yoke YK have a predetermined gap between the permanent magnet MG and the inner side walls of the side plates YKs1 and YKs2 of the yoke YK in order to keep the leakage of magnetic flux from these inner side walls to the permanent magnet MG low. A gap is provided.

The belt suction portion AT having the above-described configuration is recorded with the conveyance belt V sandwiched inside the conveyance belt V, as shown in FIG. It is disposed at a position facing the head HD.
Further, as shown in FIG. 6A, the belt suction unit AT is configured so that the suction force for sucking the transport belt V acts over the entire distance KX of the recording area KR in the recording head HD described above. The quantity of generation part AG is set. In the present embodiment, an example in which the number of magnetic force generation parts AG is three is shown.

Further, as shown in FIG. 6B, which is a right side view of FIG. 6A, the belt suction portion AT is set such that the length in the Y direction straddles the recording width KY in the recording head HD. Yes. That is, the conveyance belt V receives a suction force over the entire distance KX of the recording area KR from the belt suction unit AT.
As the permanent magnet MG, samarium-cobalt magnets mainly composed of alloys such as samarium and cobalt, neodymium-based magnets mainly composed of alloys such as neodymium, iron and boron, iron, nickel, aluminum, cobalt, etc. A permanent magnet such as an alnico magnet having an alloy as a main component, or a ferrite magnet having an alloy such as iron oxide, barium, or strontium as a main component can be employed.

As a material for the yoke YK, a soft magnetic material whose main component is an alloy containing iron, nickel, cobalt, manganese, zinc, copper, aluminum, silicon, magnesium, or the like can be used.
In addition, as the magnetic layer ML, a metal foil, an amorphous foil, or the like whose main component is an alloy such as iron, nickel, or cobalt can be employed.

As shown in FIG. 7A, which is a DD cross-sectional view in FIG. 4, the scale suction unit ST has two magnetic force generators AG sandwich the linear encoder LE in the X direction below the linear scale LS. It is arranged like this.
Here, the linear scale LS is a scale substrate formed of a non-magnetic and light-transmitting resin film or the like as shown in FIG. A scale SC is formed on a BS by laminating at a predetermined interval in the X direction from a magnetic material such as a metal foil by an etching technique or a lithography technique.

  As shown in FIG. 7C, which is a left side view of FIG. 7A, each of the two magnetic force generators AG includes a permanent magnet MG and a yoke YK. It arrange | positions so that it may oppose. Since the permanent magnet MG and the yoke YK have the same configuration as the permanent magnet MG and the yoke YK in the above-described belt attraction unit AT, detailed description thereof will be omitted.

In this scale attracting part ST, the flow FL of magnetic flux from the N pole of the permanent magnet MG reaches the scale SC through the scale base BS from the yoke YK as shown in FIG. Through the scale substrate BS again and reach the S pole.
In FIG. 7C, the thickness of the scale base BS and the scale SC is exaggerated, and the hatching of the scale base BS and the scale SC is omitted for easy understanding of the configuration.

Further, the gap provided between the permanent magnet MG and the inner side walls of the side plates YKs1 and YKs2 of the yoke YK is set to a distance sufficiently larger than the thickness of the scale base BS, and leaks between the yoke YK and the scale SC. Magnetic flux is kept low.
As shown in FIG. 2, the operation of the paper feeding unit KS is controlled by a paper feeding control unit KSD that receives a paper feeding command from the CPU, and recording is performed from a paper cassette, a paper tray, etc. (not shown) in which the recording paper P is stored. The paper P is supplied one by one to a gate roller GR described later.

  As shown in FIGS. 1A and 1B, the gate roller GR is provided on the upstream side in the X direction of the paper transport unit CV, and includes a pair of rollers that rotate while contacting the outer periphery. Yes. The gate roller GR is skew-corrected to correct the inclination of the recording paper P with respect to the X direction and the positional deviation in the Y direction when the recording paper P is supplied by the paper supply unit KS so as to abut between the pair of rollers. I do.

As shown in FIG. 2, the gate roller GR is driven by a gate roller control unit GRD that receives a paper supply command from the CPU at a predetermined timing, and the recording paper P subjected to skew correction is fed to a paper transport unit. Supply to CV.
Here, as shown in FIGS. 1A and 1B, the ink jet recording apparatus 1 contacts the conveying belt V at a position on the sheet conveying portion CV that faces the driven roller FS with the conveying belt V interposed therebetween. A pressure contact roller PR is provided.

As shown in FIGS. 1A and 1B, the pressure roller PR rotates with the recording paper P sandwiched between the outer periphery of the pressure roller PR and the conveying belt V, thereby conveying the recording belt P. It is provided to increase the adhesion to V.
The paper discharge unit EJ shown in FIG. 2 is disposed on the downstream side in the X direction of the paper conveyance unit CV. The drive is controlled by the paper discharge control unit EJD that has received a paper discharge command from the CPU and is conveyed by the conveyance belt V. The discharged recording paper P is discharged out of the inkjet recording apparatus 1.

As shown in FIGS. 1A and 1B, the ink jet recording apparatus 1 having the above-described configuration is a recording paper P that is sucked and placed on the transport belt V and transported under the recording head HD in the X direction. Recording is performed by ejecting ink droplets toward the recording surface PP.
Here, as shown in FIG. 2, in the ink jet recording apparatus 1, the transport position of the recording paper P is grasped by the CPU based on the detection signal from the linear encoder LE. Then, the CPU transfers each head unit HDK, HDC, HDM to the recording head control unit HDD at the timing when the transport position of the recording paper P becomes a transport position suitable for the recording of each of the head units HDK, HDC, HDM, and HDY. And a recording command for instructing recording in HDY.

At this time, as shown in FIG. 2, the recording head HD is controlled by the recording head control unit HDD, and the head units HDK, HDC, HDM, and HDY are moved over the distance KY based on the recording information received from the external device. Thus, recording is performed by selectively ejecting ink droplets from the nozzles NZ arranged in an array.
That is, the ink jet recording apparatus 1 completes recording without moving the recording head HD by ejecting ink droplets from the nozzles NZ onto the recording paper P that is continuously or intermittently moved under the recording head HD by the conveyance belt V. To do.

In the first embodiment, the belt suction unit AT corresponds to the belt vibration suppression unit, and the scale suction unit ST corresponds to the scale vibration suppression unit.
In the ink jet recording apparatus 1 of the first embodiment, the recording paper P is sucked and transported on the transport belt V charged by the charging roller SR. A belt suction unit AT including a magnetic force generator AG is disposed inside the transport belt V having the magnetic layer ML, and the transport belt V is rotationally driven while being attracted to the belt suction unit AT by a magnetic force. The

That is, the belt suction force at which the belt suction unit AT sucks the transport belt V is not affected by the strength of the sheet suction force of the recording paper P to the transport belt V, and the belt suction force is adjusted independently of the sheet suction force. can do. Accordingly, it is possible to reduce the vibration of the conveying belt V without changing the adsorption force of the recording paper P to the conveying belt V.
Further, the belt suction portion AT faces the recording area KR of the recording head HD with the conveyance belt V interposed therebetween. Therefore, vibration can be suppressed over the entire recording area KR of the transport belt V, and the recording quality can be improved.

  The magnetic force generator AG is composed of a permanent magnet MG and a yoke YK, and the permanent magnet MG and the yoke YK are disposed in contact with the magnetic layer ML of the transport belt V. Accordingly, the leakage of magnetic flux generated between the permanent magnet MG and the magnetic layer ML can be suppressed to be extremely low, the vibration of the transport belt V can be efficiently suppressed, and the magnetism can be reduced to other configurations of the inkjet recording apparatus 1. It is possible to prevent the environment outside the inkjet recording apparatus 1 from being affected.

  The ink jet recording apparatus 1 includes a linear encoder LE and a linear scale LS. The transport position of the recording paper P is grasped based on the detection signal from the linear encoder LE, and the transport position is suitable for recording. The recording is performed by discharging ink droplets at the timing. Furthermore, a scale attraction part ST including a magnetic force generation part AG is arranged to face the linear scale LS, and the magnetic force generation part AG attracts the magnetic scale SC.

Accordingly, the vibration of the linear scale LS is kept low by the scale suction unit ST, the stable optical detection of the scale SC by the linear encoder LE becomes possible, and the conveyance accuracy of the recording paper P is further improved.
The scale attracting part ST is configured such that the magnetic force generating part AG attracts the scale SC via the nonmagnetic scale base BS. Therefore, the frictional resistance between the scale suction part ST and the linear scale LS is kept low, and the conveyance accuracy of the recording paper P is further improved, and the scale SC is damaged by friction with the magnetic force generation part AG. Thus, the life of the linear scale LS can be improved.

In the first embodiment, the number of the magnetic force generators AG in the belt suction unit AT is three. However, the number of the magnetic force generators AG is not limited to this, and any number may be used as long as the suction force can be generated over the entire recording region KR. It can be a number.
In this case, for example, if each head unit HDK, HDC, HDM, and HDY is provided at a position facing the nozzle row of each head unit HDK, HDC, HDM, and HDY, each head unit HDK, HDC, HDM, and HDY The vibration of the conveyor belt V can be suppressed directly below the nozzle row in HDY, and the recording quality can be further improved.

Further, for example, if the magnetic force generator AG is disposed in a portion having a large amplitude according to the vibration mode of the conveying belt V that vibrates between the driving roller DS and the driven roller FS, vibration of the conveying belt V is effectively suppressed. It becomes possible to do.
In the first embodiment, the strength of the magnetic attractive force generated from each of the three magnetic force generating parts AG in the belt attractive part AT is set to be equal. However, the present invention is not limited to this. The strength may be changed.

In this configuration, for example, the strength of the attractive force of the magnetic force generator AG located at the center of the three is made stronger than the attractive force of the other two magnetic force generators AG, thereby vibrating the conveyor belt V. Can be effectively suppressed at the central portion where vibration is most likely to occur between the driving roller DS and the driven roller FS.
In the first embodiment, in the belt attraction unit AT and the scale attraction unit ST, the magnetic force generation unit AG is disposed in contact with the magnetic layer ML and the scale substrate BS, respectively, but is not limited thereto. Instead, a gap may be provided between the magnetic force generator AG and the magnetic layer ML or the scale substrate BS within a range in which an attractive force can be secured.

According to this configuration, the frictional resistance between the magnetic force generator AG and the magnetic layer ML or the scale substrate BS can be reduced, and the conveyance accuracy of the recording paper P can be improved.
Further, in this case, a gap is provided between the permanent magnet MG having a large friction coefficient between the permanent magnet MG and the yoke YK and the magnetic layer ML or the scale substrate BS, and the yoke YK having a small friction coefficient is connected to the magnetic layer ML or the scale substrate BS. If it is made to contact | abut, it becomes possible to suppress the vibration of the conveyance belt V or the linear scale LS low, reducing frictional resistance.

Further, a non-magnetic material having a low friction coefficient such as a fluororesin on a contact surface of the magnetic layer ML and the scale base BS with the magnetic force generation part AG or a contact surface of the magnetic force generation part AG with the magnetic layer ML and the scale base BS. Or a friction plate PL made of a non-magnetic material having a low friction coefficient such as a fluororesin may be interposed as shown in FIG.
According to these configurations, the frictional resistance between the conveyance belt V and the belt suction portion AT can be reduced, and the vibration of the conveyance belt V or the linear scale LS can be further suppressed, and the conveyance accuracy of the recording paper P can be improved. Further improvement is achieved.

In particular, in the case of the configuration shown in FIG. 8A, the conveyor belt V or the linear scale LS of the friction plate PL is applied to the friction belt PL as shown in FIG. By carrying out chamfering or the like on the contacting end portion H, the conveyance accuracy can be further improved.
In the first embodiment, the scale SC is formed from a magnetic material such as a metal foil by an etching technique or a lithography technique. However, the forming method is not limited to this, and magnetic ink having magnetism is recorded by inkjet recording. The scale SC may be formed on the scale substrate BS by being discharged by the apparatus.

In the first embodiment, the permanent magnet MG is disposed on the bottom surface in the concave shape of the yoke YK in each of the belt suction unit AT and the scale suction unit ST. However, the present invention is not limited to this. As shown in FIG. 9, the permanent magnet MG may be interposed in the yoke YK.
According to this configuration, compared to the belt suction portion AT shown in FIG. 5, the contact area with the conveyance belt V can be reduced, and the conveyance accuracy can be improved by reducing the frictional resistance.

The permanent magnet MG is not limited to a permanent magnet. As shown in FIGS. 10A and 10B, a coil CL is formed by winding a conductive wire around an electromagnetic core CI or a yoke YK formed of a soft magnetic material. And it is good also as an electromagnet comprised by connecting the power supply DG to the edge part of this conducting wire.
According to these configurations, it is possible to easily change the attractive force generated from each of the magnetic force generators AG by adjusting the amount of current flowing through the coil CL. Moreover, if the supply of current to the coil CL is stopped at the time of maintenance such as removing magnetic powder adhered to the magnetic force generator AG or replacing the transport belt V, the operation can be easily performed. It becomes possible.

  In the first embodiment, the configuration of the scale attraction unit ST is configured such that the two magnetic force generation units AG sandwich the linear encoder LE in the X direction. However, the configuration is not limited thereto, and as illustrated in FIG. The two magnetic force generators AG may be configured to sandwich the optical axis BL of the linear encoder LE in the Y direction. If the optical axis BL is not blocked, the direction in which the two magnetic force generators AG sandwich the optical axis BL is an arbitrary direction. I do not care.

A second embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 12, which is a front view, the ink jet recording apparatus 10 according to the second embodiment is the same as the first embodiment except that the magnetic force generation part AG of the belt suction part AT according to the first embodiment is constituted by a magnetic force generation roller MR. It has the same configuration as the inkjet recording apparatus 1 in one embodiment.

Accordingly, parts corresponding to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
As shown in FIG. 13A, which shows the details of the J portion in FIG. 12, the magnetic force generation roller MR is configured such that the transport belt V is placed on each head unit HDK, HDC, HDM and HDY inside the transport belt V. The outer periphery of the magnetic force generation roller MR is disposed in contact with the conveying belt V at a position facing the sandwich.

The magnetic force generation roller MR is configured to be rotatable with the rotation of the conveyor belt V.
Further, as shown in FIG. 13B, which is an LL sectional view in FIG. 13A, the magnetic force generation roller MR is a cylindrical permanent magnet on the outer periphery of the hollow shaft HS formed from a magnetic material. The cap CP made of a magnetic material is fitted to the both ends of the hollow shaft HS, and a gap is provided between the ends of the permanent magnet MG. The hollow shaft HS and the cap CP constitute a yoke YK. In FIG. 13B, the cross-sectional details of the head unit HDY are omitted.

Here, as shown in FIG. 14A, which is a cross-sectional view taken along line OO in FIG. 13B, the permanent magnet MG has an N pole and an S pole formed in the thickness direction.
At this time, the flow FL of the magnetic flux from the N pole of the permanent magnet MG is axially directed through the hollow shaft HS as shown in FIG. Along the cap CP and the magnetic layer ML.

In the ink jet recording apparatus 10 according to the second embodiment, the belt suction unit AT is configured by a magnetic force generation roller MR that rotates with the rotation of the transport belt V. Therefore, the frictional resistance between the belt suction unit AT and the transport belt V is low. As a result, the conveyance accuracy of the recording paper P is further improved.
In the second embodiment, the case where the N pole and the S pole of the permanent magnet MG are formed along the thickness direction of the permanent magnet MG has been described as an example. However, the present invention is not limited to this, and FIG. As shown in FIG. 4, the N pole and the S pole may be alternately formed along the circumferential direction of the cylindrical shape.

In this case, as shown in FIG. 15B, which is a cross-sectional view, the magnetic force generation roller MR is fitted with a cylindrical permanent magnet MG on the outer periphery of a solid shaft NJ formed of a nonmagnetic material. The cap CP made of a magnetic material is placed on both ends of the shaft NJ so that the end of the cap CP is in contact with the end of the permanent magnet MG.
In this configuration, the flow FL of magnetic flux from the N pole of the permanent magnet MG reaches the S pole via the magnetic layer ML on the outer peripheral surface side of the permanent magnet MG as shown in FIG. It directly reaches the south pole on the inner peripheral surface side of the magnet MG.

Here, since the solid axis NJ is a non-magnetic material, it does not form a magnetic circuit.
Further, the cap CP in this case is provided to prevent the magnetic flux from largely leaking outside at the end of the permanent magnet MG with which the cap CP is in contact, and contributes to the attractive force of the transport belt V. Not.
In the second embodiment, the scale suction unit ST in the ink jet recording apparatus 1 of the first embodiment is adopted and the description thereof is omitted. However, the vibration reducing means of the linear scale LS is not limited to this, and FIG. As shown in FIG. 16 which is an RR cross-sectional view of the inside, a belt side edge suction part RM provided with a side edge suction magnet MG2 for sucking the side edge part of the transport belt V is employed without the scale suction part ST. May be.

In this case, the conveyor belt V has a bead portion BD that protrudes inwardly at both side edges of the conveyor belt V, as shown in FIG. 16B, which is a diagram showing details of the U portion in FIG. Is formed.
The bead portion BD is formed of, for example, a resin mixed with magnetic powder and is configured so that the flexibility of the transport belt V is not impaired.

As shown in FIG. 16A, the magnetic force generation roller MR is disposed such that the outer surfaces of the caps CP at both ends are in contact with the inner surface of the bead portion BD.
As shown in FIG. 16A, the side edge attracting magnet MG2 has a cylindrical shape, and extends from the outside of the cap CP on the linear scale LS side to the shaft portion JK of the cap CP. With a gap between them.

As shown in FIG. 16B, the side edge attracting magnet MG2 has an N pole and an S pole formed in the thickness direction, and the outer peripheral surface of the side edge attracting magnet MG2 contacts the bottom surface of the bead portion BD. The thickness is set so that it touches.
At this time, the flow FL of the magnetic flux from the N pole of the side edge attracting magnet MG2 reaches the bead portion BD from the left side surface of the cap CP through the inside of the cap CP as shown in FIG. It flows through the BD and reaches the S pole from the bottom surface of the bead portion BD.

According to the above configuration, the position of the transport belt V in the Y direction is regulated by the bead portion BD and the magnetic force generation roller MR. Therefore, the vibration of the conveyor belt V can be reduced, and the meandering of the conveyor belt V in the Y direction can be suppressed.
Furthermore, since the side edge of the conveyor belt V on which the linear scale LS is disposed is sucked by the side edge suction portion RM, vibration of the linear scale LS can be reduced.

Furthermore, since the linear scale LS is not configured to be attracted by a magnetic attraction force, the scale SC engraved on the linear scale LS need not have magnetism, and a widely used linear scale is adopted. The cost can be reduced.
In the above configuration, the linear scale LS straddles the suction area AW where the suction force acts on the bead portion BD from the viewpoint of effectively suppressing the vibration of the linear scale LS, as shown in FIG. Thus, it is preferable to be disposed on the conveyor belt V.

In the first and second embodiments, the magnetic layer ML is made of a metal foil. However, the present invention is not limited to this, and the magnetic layer ML may be made of a resin layer formed by mixing magnetic powder with a resin material.
According to this configuration, the flexibility of the conveyor belt V can be improved.
In the first and second embodiments, a line type ink jet recording apparatus including four types of head units HDK, HDC, HDM, and HDY for recording black, cyan, magenta, and yellow is described as an example. However, the present invention is not limited to this, and it may be configured to include any type of head unit such as six types obtained by adding a light cyan color and a light magenta color thereto, and the configuration of the belt suction unit AT can be configured accordingly. Change it.

In the first and second embodiments, the recording head HD is arranged with the arrangement direction of the nozzles NZ oriented in the Y direction. However, the present invention is not limited to this, and the recording head HD is arranged in an arbitrary direction intersecting the X direction. You may make it arrange | position toward. In this case, the nozzle pitch viewed from the conveyance direction of the recording paper P can be set short, and the recording resolution in the Y direction can be increased.
Further, the recording medium is not limited to the recording paper P, and any recording medium can be applied as long as ink droplets can adhere to form dots.

  In the first and second embodiments, the example in which the sheet conveyance unit CV is applied to the line-type inkjet recording apparatus has been described. However, the present invention is not limited to this, and the Y direction perpendicular to the conveyance direction of the recording sheet P is not limited thereto. The present invention can also be applied to a serial type ink jet recording apparatus that performs recording while scanning.

1 is an external view showing a main configuration of an ink jet recording apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a connection of control of main parts of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a recording head of the ink jet recording apparatus according to the first embodiment of the invention. FIG. 3 is a diagram illustrating a linear scale of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a magnetic force generation unit of a belt suction unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a belt suction unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a scale suction unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating another configuration of the magnetic force generation unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating another configuration of the permanent magnet of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating another example of a magnetic force generation unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating another configuration of the scale suction unit of the ink jet recording apparatus according to the first embodiment of the present invention. The front view of the inkjet recording device in 2nd Embodiment of this invention. The figure explaining the structure of the magnetic force generation roller of the inkjet recording device in 2nd Embodiment of this invention. The figure explaining the flow of the magnetic flux of the magnetic force generation roller of the inkjet recording device in 2nd Embodiment of this invention. FIG. 6 is a diagram illustrating another configuration of a magnetic force generation roller of an ink jet recording apparatus according to a second embodiment of the invention. The figure explaining the structure of the side edge suction part of the inkjet recording device in 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,10 ... Inkjet recording device, HD ... Recording head, HDK, HDC, MDM, HDY ... Head unit, V ... Conveyor belt, ML ... Magnetic layer, AT ... Belt suction part, AG ... Magnetic force generation part, MG ... Permanent magnet YK ... Yoke, ST ... Scale suction part, LE ... Linear encoder, LS ... Linear scale, SC ... Scale, MR ... Magnetic force generating roller

Claims (14)

Recording medium conveying means for conveying a recording medium adsorbed to an endless conveying belt by the action of static electricity, and a recording head for performing recording by ejecting ink droplets from nozzles onto the recording medium conveyed by the recording medium conveying means An inkjet recording apparatus comprising:
The conveyor belt is formed with a magnetic layer having magnetism,
An ink jet recording apparatus comprising belt vibration suppression means that opposes the magnetic layer on the inner side of the conveyor belt and that attracts the magnetic layer by magnetic force to suppress vibration of the conveyor belt.   The inkjet recording apparatus according to claim 1, wherein the magnetic layer is formed on an inner peripheral surface of the transport belt. The recording head spans the recording medium along a direction intersecting the transport direction so that the plurality of nozzles can form dots aligned in a single row in a main scanning direction orthogonal to the transport direction of the recording medium. Having a configuration arranged over a distance;
3. The ink jet recording apparatus according to claim 1, wherein the belt vibration suppressing unit is disposed so as to face at least a region where the recording head performs recording on the recording medium.   4. The ink jet recording apparatus according to claim 1, wherein the belt vibration suppressing unit is configured to form a magnetic circuit with a magnetic force generation unit and a magnetic yoke. 5.   The inkjet recording apparatus according to claim 4, wherein the magnetic force generation unit is formed of a permanent magnet.   5. The inkjet according to claim 4, wherein the magnetic force generator includes an electromagnet, a power source that supplies a current to the electromagnet, and a current adjustment unit that changes the amount of the current. Recording device.   The inkjet recording apparatus according to claim 4, wherein the magnetic force generation unit includes a cylindrical permanent magnet, and is a magnetic force generation roller configured to be rotatable with the rotation of the transport belt.   The inkjet recording apparatus according to claim 1, wherein the belt vibration suppressing unit is disposed in contact with the magnetic layer.   The belt vibration suppressing means is disposed in contact with the conveyor belt via a nonmagnetic layer formed of a material having nonmagnetic properties and a low friction coefficient between the belt and the magnetic layer. The ink jet recording apparatus according to claim 1. A linear scale disposed on the transport belt and having a plurality of scales formed at predetermined intervals along the transport direction of the recording medium; an encoder that optically detects the scale and outputs a detection signal; and the detection signal A transport position grasping means for grasping the transport position of the recording medium that is sucked and placed on the transport belt, and the transport position grasped by the transport position grasping means is a transport position suitable for the recording. A head driving means for driving the recording head so that the ink droplets are ejected from the nozzles at a timing that becomes,
The linear scale is formed of a material in which the scale has magnetism,
The inkjet according to any one of claims 1 to 9, further comprising a scale vibration suppressing unit that faces the linear scale and sucks the scale by a magnetic force to suppress vibration of the linear scale. Recording device.   The ink jet recording apparatus according to claim 10, wherein the scale vibration suppressing unit is configured to form a magnetic circuit with a magnetic force generation unit and a magnetic yoke.   The inkjet recording apparatus according to claim 11, wherein the magnetic force generation unit is configured by a permanent magnet.   The inkjet according to claim 11, wherein the magnetic force generation unit includes an electromagnet, a power source that supplies a current to the electromagnet, and a current adjustment unit that changes an amount of the current. Recording device.   14. The scale vibration suppression means is in contact with the linear scale through a nonmagnetic layer formed of a material having nonmagnetic properties and a low friction coefficient between the scale and the scale. The ink jet recording apparatus according to any one of the above.

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