JP2008183724A - Inkjet printer - Google Patents

Abstract

Provided is an ink jet printer in which a print medium is unlikely to float when transferred between transport belts in the upstream and downstream of the print medium transport direction.
A plurality of conveying units, each having a plurality of conveying belts (6, 7) arranged at a predetermined interval in a direction intersecting the printing medium conveying direction, are arranged along the printing medium conveying direction. When printing is performed by ejecting ink droplets from the inkjet heads 2 and 3 onto the print medium 1 that is electrostatically attracted and conveyed by the ink jet, the conveyance belt 6 on the upstream side in the print medium conveyance direction and the conveyance belt on the downstream side in the print medium conveyance direction 7 at the time of transfer between the conveying belts 6 and 7 upstream and downstream in the printing medium conveying direction by alternately superposing the conveying belts 6 and 7 in the direction intersecting the printing medium conveying direction. Since the print medium 1 is adsorbed by the transport belts 6 and 7 of the rendition style, it is possible to reliably prevent the print medium 1 from floating.
[Selection] Figure 1

Description

  In the present invention, for example, minute characters of liquid inks of a plurality of colors are ejected from a plurality of nozzles to form fine particles (ink dots) on a print medium, thereby drawing a predetermined character or image. The present invention relates to an ink jet printer.

Such an inkjet printer is generally inexpensive and can easily obtain a high-quality color printed matter. Accordingly, along with the widespread use of personal computers and digital cameras, it has become widespread not only in offices but also in general users.
Such an ink jet printer generally has an ink jet head head while a moving body called a carriage, which is integrally provided with an ink cartridge and an ink jet head, reciprocates on a print medium in a direction intersecting the transport direction. By ejecting (injecting) liquid ink droplets from the nozzles to form minute ink dots on the print medium, a predetermined character or image is drawn on the print medium to create a desired printed matter. ing. The carriage is equipped with four color (yellow, magenta, cyan) ink cartridges including black (black) and a print head for each color, so that not only monochrome printing but also full-color printing combining each color is easy. (Furthermore, 6 colors, 7 colors, or 8 colors in which light cyan, light magenta, etc. are added to these colors are also put into practical use).

  Further, in this type of ink jet printer in which printing is executed while reciprocating the ink jet head on the carriage in a direction intersecting with the conveyance direction of the print medium, the ink jet head is set to 10 to cleanly print the entire page. It is necessary to reciprocate several times to several tens of times. In contrast, in an inkjet printer of a type in which a long inkjet head (not necessarily integrated) having the same dimensions as the width of the print medium is disposed and the carriage is not used, the inkjet head is moved in the width direction of the print medium. There is no need, and so-called one-pass printing is possible, so that high-speed printing is possible. The former inkjet printer is generally referred to as a “multi-pass (serial) inkjet printer”, and the latter inkjet printer is generally referred to as a “line head inkjet printer”.

In such an ink jet printer, for example, an electric charge is applied to the transport belt to charge it, and a print medium made of almost an insulator is electrostatically adsorbed to the transport belt and transported, and ink droplets are ejected from the ink jet head onto the transported print medium. There are some which perform printing by discharging. In addition, there is also a type in which a print medium is adsorbed on a conveyance belt and conveyed by negative air pressure. Such a print medium conveying method is particularly effective in a line head type ink jet printer. The ink jet printer described in the following Patent Document 1 distributes a line head type ink jet head in two places on the upstream side and the downstream side in the transport direction of the print medium, and in the direction intersecting the transport direction of the print medium. Two sets of transport units arranged at a predetermined interval are arranged in the print medium transport direction corresponding to the ink jet head, and the print medium is electrostatically adsorbed to the transport belt and transported, and the transport unit is placed on the transported print medium. Printing is performed by ejecting ink droplets from two downstream inkjet heads. The inkjet head is disposed in a gap portion between the conveyance belts, and performs a so-called cleaning that recovers a nozzle defect using a cleaning unit disposed immediately below the inkjet belt.
JP-A-2005-75475

By the way, in the ink jet printer in which the transport units composed of a plurality of transport belts as described in Patent Document 1 are arranged in the print medium transport direction, for example, the print medium transport from the transport belt of the upstream transport unit in the print medium transport direction. When the print medium is transferred to the conveyance belt of the conveyance unit on the downstream side in the direction, when viewed from the width direction of the conveyance belt, the print medium is transferred from the conveyance belt on the conveyance unit in the conveyance direction to the conveyance unit on the downstream side in the conveyance direction. Transfer to the conveyor belt (if the print medium is viewed in plan, change to a linear shape). However, the printing medium on which ink droplets are ejected from the inkjet head upstream in the printing medium conveyance direction is wavy (cockling) due to swelling, and the portion that is swollen by the ink droplets and protrudes upward is the printing medium. Since it is on the conveyance belt of the conveyance unit on the downstream side in the conveyance direction, the transfer of the print medium is unstable and the float tends to occur. This floating of the print medium causes a conveyance failure of the print medium, so-called paper jam and image quality deterioration.
The present invention has been made paying attention to the above-described problems, and provides an ink jet printer in which the printing medium is unlikely to float when transferring between conveying belts upstream and downstream in the conveying direction of the printing medium. It is intended.

  In order to solve the above-described problems, an inkjet printer according to the present invention includes a plurality of conveyance units arranged along a print medium conveyance direction in which a plurality of conveyance belts are arranged at predetermined intervals in a direction intersecting the print medium conveyance direction. An inkjet printer that performs printing by ejecting ink droplets from an inkjet head onto a print medium that is adsorbed and conveyed by the plurality of conveyance belts, the conveyance belt of the upstream conveyance unit and the print medium conveyance direction A simultaneous suction area in which the print medium is simultaneously sucked by the transport belt of the downstream transport unit is provided.

According to the present invention, by providing the simultaneous suction area in which the print medium is simultaneously sucked by the transport belt of the upstream transport unit in the print medium transport direction and the transport belt of the downstream transport unit in the print medium transport direction, In the transfer between the conveyance belts upstream and downstream in the direction, the printing medium is unlikely to float.
In the ink jet printer of the present invention, in the simultaneous suction region, a direction in which the conveyance belt of the upstream conveyance unit in the print medium conveyance direction and the conveyance belt of the downstream conveyance unit in the print medium conveyance direction intersect with the print medium conveyance direction. It is characterized by being alternately polymerized and arranged.

According to the present invention, it is possible to reliably prevent the printing medium from floating when transferring between the conveyance belts in the upstream and downstream of the printing medium conveyance direction.
In the ink jet printer of the present invention, the transport belt adsorbs the print medium with electrostatic force.
Furthermore, the ink jet printer of the present invention is configured such that, in the simultaneous suction region, the two are mutually connected at the overlapping portion of the transport belt of the transport unit upstream in the print medium transport direction and the transport belt of the transport unit downstream in the print medium transport direction. Each of the conveyor belts is charged so as to have a reverse polarity.

According to these inventions, the print medium can be adsorbed by the electric field generated between the adjacent conveyance belts, so that the print medium can be more lifted when transferring between the conveyance belts upstream and downstream in the print medium conveyance direction. This can be prevented more reliably.
In the inkjet printer according to the aspect of the invention, it is preferable that the conveyance belt adsorbs the print medium with negative air pressure.

Next, a first embodiment of the inkjet printer of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the ink jet printer of the present embodiment, FIG. 1a is a plan view thereof, and FIG. 1b is a front view thereof. In FIG. 1, a print medium 1 is a line head type ink jet printer that is transported in the direction of the arrow in the figure from the right to the left in the figure, and is printed in a print area in the middle of the conveyance. However, the ink jet head of the present embodiment is arranged not only at one place but also at two places.

Reference numeral 2 in the figure denotes a first inkjet head provided on the upstream side in the conveyance direction of the print medium 1, and reference numeral 3 denotes a second inkjet head provided on the downstream side, and below the first inkjet head 2. Is provided with a first transport unit 4 for transporting the print medium 1, and a second transport unit 5 is provided below the second inkjet head 3. The first transport unit 4 includes five first transport belts 6 arranged at predetermined intervals in a direction intersecting with the transport direction of the print medium 1 (hereinafter also referred to as nozzle row direction). Similarly, the second transport unit 5 includes six second transport belts 7 arranged at predetermined intervals in a direction (nozzle row direction) intersecting the transport direction of the print medium 1. In this embodiment, a superposition part is formed in which the first transport belt 6 of the first transport part 4 and the second transport belt 7 of the second transport part 5 are superposed, and this superposition part constitutes the simultaneous adsorption region of the present invention. To do. Note that each of the first transport belt 6 and the second transport belt 7 has a single-layer belt made of an insulating resin such as PET, polyimide, or fluorine resin, or a surface layer that electrostatically attracts the print medium 1. These insulating resin layers and back layers are constituted by a two-layer belt having a resistance layer of 10 ¹⁰ Ω / □ or less, for example.

  The six second conveyor belts 7 as well as the five first conveyor belts 6 are arranged in a so-called staggered pattern so as to be alternately adjacent to each other. In the superposition part of the 1st conveyance part 4 and the 2nd conveyance part 5 which were mentioned above, it is the middle of the 1st inkjet head 2 and the 2nd inkjet head 3, and a printing medium conveyance line (meaning the conveyance height of the printing medium 1). A drive roller 8 is disposed below the first ink jet head 2, and an upstream first driven roller 9 a is disposed upstream of the first inkjet head 2 in the print medium conveyance direction and directly below the print medium conveyance line. A downstream first driven roller 9b is disposed downstream in the transport direction and upstream of the second ink jet head 3 in the print medium transport direction and immediately below the print medium transport line. The drive roller 8 and the upstream first follower are disposed. The first conveyor belt 6 is wound around the roller 9a and the first downstream driven roller 9b. An upstream second driven roller 10a is disposed upstream of the drive roller 8 in the print medium conveyance direction, downstream of the first inkjet head 2 and directly below the print medium conveyance line, and the second inkjet head. A downstream second driven roller 10b is disposed on the downstream side in the print medium transport direction 3 and directly below the print medium transport line, and is connected to the drive roller 8, the upstream second driven roller 10a, and the downstream second driven roller 10b. 2 The conveyor belt 7 is wound. As a result, the first conveying belt 6 of the first conveying unit 4 that is the upstream conveying unit in the printing medium conveying direction, and the second conveying belt 7 of the second conveying unit 5 that is the downstream conveying unit in the printing medium conveying direction, Are alternately superposed in the direction crossing the print medium conveyance direction.

  The drive roller 8 is connected to an electric motor (not shown). Therefore, when the drive roller 8 is rotationally driven by the electric motor, the first transport unit 4 configured by the first transport belt 6 and the second transport unit 5 configured by the second transport belt 7 are synchronized with each other and at the same speed. Move with. In order to charge the first conveying belt 6 and the second conveying belt 7 by a first charging roller 22 and a second charging roller 25, which will be described later, the upstream first driven roller 9a and the driving roller 8 are grounded.

  The first inkjet head 2 and the second inkjet head 3 are shifted in the transport direction of the printing medium 1 for each of four colors, for example, yellow (Y), magenta (M), cyan (C), and black (K). It is arranged. Ink is supplied to each inkjet head 2 and 3 from an ink tank of each color (not shown) via an ink supply tube. Each inkjet head 2, 3 is formed with a plurality of nozzles in the direction intersecting with the conveyance direction of the print medium 1 (that is, in the nozzle row direction), and a necessary amount of ink droplets are simultaneously applied from the nozzles to necessary locations. By discharging, minute ink dots are formed and output on the printing medium 1. By performing this for each color, it is possible to perform so-called one-pass printing by passing the print medium 1 conveyed by the first conveyance unit 4 and the second conveyance unit 5 once. That is, the area where the inkjet heads 2 and 3 are disposed corresponds to the printing area.

  As a method for discharging and outputting ink from each nozzle of the ink jet head, there are an electrostatic method, a piezo method, a film boiling ink jet method, and the like. In the electrostatic system, when a drive signal is given to the electrostatic gap, which is an actuator, the diaphragm in the cavity is displaced, causing a pressure change in the cavity, and ink drops are ejected from the nozzle by the pressure change. It is. In the piezo method, when a drive signal is given to a piezo element that is an actuator, the diaphragm in the cavity is displaced to cause a pressure change in the cavity, and ink droplets are ejected from the nozzle by the pressure change. . In the film boiling ink jet method, there is a minute heater in the cavity, the ink is instantaneously heated to 300 ° C. or more, the ink becomes a film boiling state, bubbles are generated, and ink droplets are ejected from the nozzle by the pressure change. That's it. The present invention can be applied to any ink output method, but is particularly suitable for a piezo element that can adjust the ejection amount of ink droplets by adjusting the peak value of the drive signal and the voltage increase / decrease slope.

  The first inkjet head 2 is formed only between the five first conveyance belts 6 of the first conveyance unit 4 and at both ends thereof, and the second inkjet head 3 is composed of six second conveyance belts of the second conveyance unit 5. It is formed only between the conveyor belts 7. This is because the inkjet heads 2 and 3 are cleaned by a cleaning unit, which will be described later, but in this way, one-pass printing cannot be performed with only one of the inkjet heads. For this reason, the first ink jet head 2 and the second ink jet head 3 are arranged so as to be shifted in the transport direction of the print medium 1 in order to compensate for the portions that cannot be printed with each other. All nozzles have independent actuators, each of which is provided with a selection switch.

  A first cleaning cap (not shown) for cleaning the first inkjet head 2 is disposed below the first inkjet head 2, and the second inkjet head 3 is disposed below the second inkjet head 3. A second cleaning cap (not shown) for cleaning is provided. Each of the cleaning caps is formed to have a size that can pass between the five first conveying belts 6 of the first conveying unit 4 and between the six second conveying belts 7 of the second conveying unit 5. is there. These cleaning caps, for example, have a rectangular bottomed cap body that covers the nozzles formed on the lower surfaces of the inkjet heads 2 and 3, that is, the nozzle surfaces and can be in close contact with the nozzle surfaces, and the ink disposed on the bottoms thereof. An absorber, a tube pump connected to the bottom of the cap body, and a lifting device for lifting and lowering the cap body are provided.

  Therefore, each cleaning cap is lifted by the lifting device and is brought into close contact with the nozzle surfaces of the inkjet heads 2 and 3. In this state, when the cap body is made negative pressure by the tube pump, ink droplets and bubbles are sucked out from the nozzles established on the nozzle surfaces of the ink jet heads 2 and 3, and the ink jet heads 2 and 3 can be cleaned. . When cleaning is completed, the cleaning cap is lowered. In some cases, the meniscus of each nozzle may be adjusted by stroking the nozzle surface with a wiper. In addition, when performing so-called flushing in which ink droplets are ejected in the absence of the print medium 1 to recover or maintain the nozzle in a normal state, the cleaning caps are not brought into close contact with the nozzle surfaces of the inkjet heads 2 and 3. May be.

  On the upstream side of the upstream first driven roller 9a, a pair of two gate rollers 14 that adjust the feeding timing of the printing medium 1 supplied from the feeding unit and correct the skew of the printing medium 1 are printed. It is provided so as to sandwich the medium transport line. The skew is a twist of the print medium 1 with respect to the transport direction. Further, two pairs of feed rollers 16 for supplying the print medium 1 are provided on the upstream side of the gate roller 14 so as to sandwich the print medium conveyance line. Reference numeral 15 in the drawing denotes a pressure roller that presses the printing medium 1 against the upstream first driven roller 9a and electrostatically attracts the printing medium 1 to the first conveying belt 6 as will be described later.

In the present embodiment, a first belt cleaning roller 11 is disposed below the first conveyance belt 6, and a second belt cleaning roller 12 is disposed below the second conveyance belt 7. These belt cleaning rollers 11 and 12 are composed of sponge rollers such as urethane that easily absorb ink.
In addition, a first flat surface restricting body 17 for restricting the flatness of the print medium 1 is provided below the print area by the first ink jet head 2 described above, and a second flat surface restricting body is provided below the print area by the second ink jet head 3. 18 is provided. These plane regulating bodies 17 and 18 are generally called platens, and support the trajectories of the conveyor belts 6 and 7 from below and regulate the flatness of the print medium 1 electrostatically attracted thereto.

  A first charging roller 22 as a charging means for charging the first conveying belt 6 is disposed below the upstream first driven roller 9a, and the first conveying roller 9a is sandwiched between the first conveying roller 9a and the first conveying roller 6a. It is in contact with the belt 6. A second charging roller 25 is disposed below the driving roller 8 as a charging unit that charges the second conveying belt 7 and is in contact with the second conveying belt 7 with the driving roller 8 interposed therebetween. Both the first charging roller 22 and the second charging roller 25 are connected to a power source 23, and positive and negative charges are alternately applied by an alternating voltage of about several kVp-p. Generally, these belts are composed of a medium / high resistance body or an insulator, and the surface (outer peripheral surface) of the first conveyance belt 6 and the second conveyance belt 7 are alternately charged to opposite polarities by a belt charging device. Then, for example, an electric field generated between adjacent polarities, that is, an electrostatic force becomes an adsorption force, and the print medium 1 can be electrostatically adsorbed. Note that the conveying belt charging method may be a DC voltage in addition to the alternating voltage. In this case, dielectric polarization occurs in the print medium 1 due to the potential of the transport belt, and a potential difference is generated between the polarized print medium 1 and the first transport belt 6 and the second transport belt 7, which becomes an adsorption force. The print medium 1 is electrostatically adsorbed on the surfaces of the first conveyance belt 6 and the second conveyance belt 7.

  Therefore, according to this ink jet printer, the surface of the first conveyor belt 6 is charged by the first charging roller 22 and the surface of the second conveyor belt 7 is charged by the second charging roller 25. When the printing medium 1 is fed and the printing medium 1 is pressed against the first conveying belt 6 by the pressure roller 15, the printing medium 1 is electrostatically adsorbed on the surface of the first conveying belt 6 by the above-described adsorption force due to the electric field. In this state, when the driving roller 8 is rotationally driven by the electric motor, the rotational driving force is transmitted to the upstream first driven roller 9a and the downstream first driven roller 9b via the first conveying belt 6.

  In this way, with the print medium 1 electrostatically adsorbed, the first conveyor belt 6 is moved downstream in the conveyance direction, the print medium 1 is moved below the first inkjet head 2, and the first inkjet head 2 is moved to the first inkjet head 2. Printing is performed by ejecting ink droplets from the nozzles formed. When the printing by the first ink jet head 2 is completed, the print medium 1 is moved downstream in the transport direction and transferred onto the second transport belt 7 of the second transport unit 5. As described above, since the surface of the second conveyance belt 7 is also charged by the second charging roller 25, the print medium 1 is electrostatically adsorbed on the surface of the second conveyance belt 7 by the adsorption force due to the electric field described above.

  In this state, the second conveying belt 7 is moved downstream in the conveying direction, the printing medium 1 is moved below the second inkjet head 3, and ink droplets are ejected from the nozzles formed on the second inkjet head 3. And print. When printing by the second ink jet head is completed, the print medium 1 is further moved downstream in the transport direction, and the print medium 1 is discharged from the outer peripheral surface of the second transport belt 7 to the paper discharge unit while being separated by a separation device (not shown). Make paper.

  When the first and second inkjet heads 2 and 3 need to be cleaned, the first and second cleaning caps 12 and 13 are raised as described above to raise the nozzle surfaces of the first and second inkjet heads 2 and 3. In this state, the cap body is brought into a negative pressure so that ink drops and bubbles are sucked out from the nozzles of the first and second ink jet heads 2 and 3 and cleaned. 2 Lower the cleaning caps 12 and 13.

  In the present embodiment, the overlapping portion of the first transport unit 4 and the second transport unit 5 includes the first transport belt 6 of the first transport unit 4 on the upstream side in the print medium transport direction and the downstream side in the print medium transport direction. Since the second conveying belt 7 of the second conveying unit 5 is alternately superposed in the direction intersecting the printing medium conveying direction, printing is performed from the first conveying belt 6 on the upstream side in the printing medium conveying direction. When the printing medium 1 is transferred to the second conveying belt 7 on the downstream side in the medium conveying direction, the printing medium 1 is simultaneously adsorbed by the first conveying belt 6 and the second conveying belt 7. Therefore, this region corresponds to the simultaneous adsorption region of the present invention. In particular, in the present embodiment, ink droplets are ejected from the first inkjet head 2 on the upstream side in the printing medium conveyance direction, and as a result, the portion of the printing medium 1 that swells and swells upward with the ink droplets is Since the other parts can be adsorbed by the second conveying belt 7 while being adsorbed by the first conveying belt 6, the printing medium 1 can be reliably prevented from floating.

  As described above, according to the ink jet printer of the present embodiment, a plurality of transport units in which the plurality of transport belts 6 and 7 are arranged at predetermined intervals in the direction intersecting the print medium transport direction are arranged along the print medium transport direction. When printing is performed by ejecting ink droplets from the inkjet heads 2 and 3 onto the print medium 1 that is transported by adsorbing the print medium 1 to the transport belts 6 and 7, transport upstream in the print medium transport direction By providing a simultaneous suction region in which the print medium 1 is simultaneously sucked by the belt 6 and the transport belt 7 on the downstream side in the print medium transport direction, the transfer between the transport belts 6 and 7 on the upstream and downstream in the print medium transport direction is performed. The printing medium 1 is unlikely to float.

Further, in the simultaneous suction region, the upstream conveying belt 6 in the printing medium conveying direction and the conveying belt 7 downstream in the printing medium conveying direction are alternately superposed in the direction intersecting with the printing medium conveying direction. It is possible to reliably prevent the printing medium 1 from being lifted when transferring between the conveying belts 6 and 7 in the upstream and downstream of the printing medium conveyance direction.
In addition, since the transport belts 6 and 7 adsorb the print medium by electrostatic force, the invention can be easily implemented.

  FIG. 2 shows another example of the conveying belt winding method. In FIG. 2a, one driven roller 51 is added above the driving roller 8, and the first conveying belt 6 from the driving roller 8 toward the upstream first driven roller 9a and the driving roller 8 toward the downstream second driven roller 10b. The second conveyor belt 7 is loosened in the shape of “8”. In FIG. 2b, two driven rollers 52 are arranged above the drive roller 8 in the print medium conveyance direction, and among these, the driven roller 52 on the upstream side in the print medium conveyance direction is connected to the first upstream side from the drive roller 8. The first conveyance belt 6 that is directed toward the driven roller 9a is wound, and the second conveyance belt 7 that is directed from the drive roller 8 toward the downstream second driven roller 10b is wound around the driven roller 52 that is downstream in the print medium conveyance direction. is there. These are all for increasing the winding angle of the conveyor belts 6 and 7 around the drive roller 8.

  Next, a second embodiment of the ink jet printer of the present invention will be described with reference to FIG. The original functional configuration of the ink jet printer of the present embodiment is the same as that of FIG. 1 of the first embodiment, so that the same components are denoted by the same reference numerals and detailed description thereof is omitted. . Further, the plan view of the ink jet printer of the present embodiment is the same as FIG.

  In the present embodiment, the first charging roller 22 is connected to the power source 23 as in the first embodiment, but the second charging roller 25 is connected to a separate power source 24. And in this embodiment, by adjusting the phase of the alternating voltage of these power supplies 23 and 24, as shown in FIG. 4, the superposition | polymerization part of the 1st conveyance part 4 and the 2nd conveyance part 5 which are simultaneous adsorption | suction area | regions 1, the first conveyance belt 6 of the first conveyance unit 4 on the upstream side in the printing medium conveyance direction and the second conveyance belt 7 of the second conveyance unit 5 on the downstream side in the printing medium conveyance direction are opposite to each other. The conveyor belts 6 and 7 are charged. In this case, since the adjacent conveyance belts 6 and 7 in the simultaneous adsorption region have opposite polarities, an electric field is generated between them, and the print medium 1 is adsorbed by this electric field, so the upstream side in the print medium conveyance direction It is possible to reliably prevent the printing medium 1 from being lifted when transferring from the first conveying belt 6 of the first conveying unit 4 to the second conveying belt 7 of the second conveying unit 5 on the downstream side in the printing medium conveying direction.

  As described above, according to the ink jet printer of the present embodiment, in addition to the operational effects of the ink jet printer of the first embodiment, at least in the simultaneous suction region, the first of the first transport unit 5 on the upstream side in the print medium transport direction. Because the respective conveying belts 6 and 7 are charged so that they are opposite in polarity at the overlapping portion of the conveying belt 6 and the second conveying belt 7 of the second conveying unit 5 on the downstream side in the printing medium conveying direction. The print medium 1 can be adsorbed by the electric field generated between the adjacent conveyance belts 6 and 7, so that the print medium 1 floats when transferring between the conveyance belts 6 and 7 in the print medium conveyance direction. Can be more reliably prevented.

  Next, a third embodiment of the ink jet printer of the present invention will be described with reference to FIG. The original functional configuration of the ink jet printer according to this embodiment is the same as that of FIG. 1 of the first embodiment except that the method for adsorbing the print medium onto the transport belt is different. The same reference numerals are given and detailed description thereof is omitted. The layout of the conveyor belts 6 and 7 is the same as that in the first embodiment.

  Each of the conveyor belts 6 and 7 of the present embodiment is provided with many small holes for air suction. FIG. 6 is a plan view in which the conveyor belt is removed from the plan view of FIG. 5a. A thin box-shaped duct 31 whose upper surface is a mesh is disposed in a portion immediately below the print medium conveyance line among the conveyance belts 6 and 7, and these ducts 31 pass through the plane regulation bodies 17 and 18. The common duct 32 is connected to the suction fan 19. FIG. 7 shows a cross section of the upstream side second driven roller 10a and the duct 31 as a representative of the joint portion between the duct 31 and the driven rollers 9b and 10a. As is clear from the drawing, the upstream second driven roller 10a and the interference portion of the duct 31 correspond to each other by cutting out the upstream second driven roller 10a.

  Therefore, in the ink jet printer of the present embodiment, when the air in the common duct 32 and the duct 31 is sucked by the suction fan 19, the print medium 1 is transferred to the transport belt 6 by the negative air pressure through the holes of the transport belts 6 and 7. 7 is adsorbed. Also in the present embodiment, in the overlapping portion of the first transport unit 4 and the second transport unit 5, the duct 31 of the first transport belt 6 of the first transport unit 4 on the upstream side in the print medium transport direction and the print medium transport Since the duct 31 of the second conveying belt 7 of the second conveying unit 5 on the downstream side in the direction is arranged in an overlapping manner in the direction intersecting the printing medium conveying direction, the second conveying belt 5 on the upstream side in the printing medium conveying direction is arranged. When the printing medium 1 is transferred from the first conveying belt 6 to the second conveying belt 7 on the downstream side in the conveying direction of the printing medium, the printing medium 1 is simultaneously sucked by the first conveying belt 6 and the second conveying belt 7.

Thus, according to the ink jet printer of this embodiment, since the conveyance belts 6 and 7 adsorb the print medium 1 with negative air pressure, the invention can be easily implemented.
In each of the above embodiments, only an example in which the ink jet printer of the present invention is applied to a so-called line head type ink jet printer has been described in detail. However, the ink jet printer of the present invention is not limited to a multi-pass type printer. The present invention can be applied to all types of inkjet printers that are attracted by a plurality of conveyance belts.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows 1st Embodiment of the inkjet printer of this invention, (a) is a top view, (b) is a front view. It is explanatory drawing which shows another example of the winding method of a conveyance belt. It is a schematic structure front view which shows 2nd Embodiment of the inkjet printer of this invention. It is explanatory drawing of the charging state of the conveyance belt of the inkjet printer of FIG. It is a schematic block diagram which shows 3rd Embodiment of the inkjet printer of this invention, (a) is a top view, (b) is a front view. It is explanatory drawing of the state which removed the conveyance belt from the inkjet printer of FIG. It is explanatory drawing of the engagement of the driven belt and duct of the inkjet printer of FIG.

Explanation of symbols

  1 is a print medium, 2 is a first inkjet head, 3 is a second inkjet head, 4 is a first transport unit, 5 is a second transport unit, 6 is a first transport belt, 7 is a second transport belt, and 8 is driven Rollers, 9a and 9b are first driven rollers, 10a and 10b are second driven rollers, 11 and 12 are belt cleaning rollers, 14 is a gate roller, 15 is a pressure roller, 16 is a feed roller, and 17 is a first plane regulator. , 18 is a second plane regulating body, 19 is a suction fan, 22 is a first charging roller, 23 and 24 are power supplies, 25 is a second charging roller, 31 is a duct, and 32 is a common duct.

Claims (5)

  Printing in which a plurality of conveying units having a plurality of conveying belts arranged at predetermined intervals in a direction intersecting the printing medium conveying direction are arranged along the printing medium conveying direction, and are sucked and conveyed by the plurality of conveying belts. An inkjet printer that performs printing by ejecting ink droplets from an inkjet head onto a medium, and the print medium is simultaneously adsorbed by the conveyance belt of the upstream conveyance unit in the print medium conveyance direction and the conveyance belt of the downstream conveyance unit in the print medium conveyance direction. An ink jet printer characterized in that a simultaneous suction area is provided.   In the simultaneous suction area, the conveyance belt of the upstream conveyance unit in the printing medium conveyance direction and the conveyance belt of the downstream conveyance unit in the printing medium conveyance direction are alternately superposed in the direction intersecting the printing medium conveyance direction. The inkjet printer according to claim 1.   The inkjet printer according to claim 2, wherein the conveyance belt attracts the print medium with electrostatic force.   In the simultaneous adsorption region, the respective conveying belts are configured such that both are opposite in polarity at the overlapping portion of the conveying belt of the upstream conveying unit in the printing medium conveying direction and the conveying belt of the downstream conveying unit in the printing medium conveying direction. The inkjet printer according to claim 3, wherein the inkjet printer is charged.   The inkjet printer according to claim 2, wherein the conveyance belt adsorbs a print medium with negative air pressure.

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